The Influence of the Vernacular by roalbak

Fig. 1

Cover. House in Tehuantepec. Taken by author

The Influence of the Vernacular Building traditions in contemporary housing architecture of hot climates in Mexico

Rodrigo Alba Krasovsky FS 110370

WS16 - SS19

Doctoral Thesis To obtain the degree of Doctor of Philosophy in Architecture and Planning

University of Liechtenstein Graduate School

Supervisor: Prof. Dipl. Arch. ETH/SIA Dietrich Schwarz Second supervisor: Dr. Carlos Estuardo Aparicio Moreno

Date of submission: 14/05/2019

ACKNOWLEDGEMENTS

Throughout this journey that began three years ago, I have received a lot of support and

assistance. I would first like to thank my supervisor and mentor Prof. Dietrich Schwarz, who has advised and encouraged me since I arrived at the University of Liechtenstein. His guidance in academia and practice has shaped my path through sustainable architecture, and I will always be grateful for all the shared experiences and knowledge, hoping that our collaboration continues in the future.

My sincere gratitude to my second supervisor Dr. Carlos Aparicio, whose deep knowledge

of the Monterrey Metropolitan Area and his research served as a reference for this study. Thanks for his continuous support and insightful comments and advice. 4

I would also like to thank the professors and staff of the University of Liechtenstein. Peter

Staub, Esther Kind, Ines Hartmann, Jeannette Risch, Carmen Rist, Cornelia Faisst, Anne Brandl, Anne-Sophie Zapf, Christoph Michels, among many others have supported me in many different ways. My thanks also goes to all my PhD colleagues, for the exchange of ideas and thoughts, especially to Laura Baumgärtner and Roope Jaakonmäki for their insights and friendship.

To Gabriela Cortés, who has been like part of my family since I arrived in Liechtenstein,

and has always helped me inside and outside of the University. Thanks also to the Hasler family, for their friendship and support throughout the years in this country.

I would also like to acknowledge all the students from the Studio Schwarz, where I had

the chance to be an assistant professor. Their projects and visions for Mexico City and the Istmo de Tehuantepec are an inspiration for my work and this dissertation.

I gratefully acknowledge the funding received from CONACYT for the completion of my

dissertation. I am also grateful to all the participants and interviewees of this research. Thanks to all the people that opened the door of their houses and supported this study.

Thanks to all my friends from the University and in Mexico who have always backed me

up. Special thanks to Sebastian Bobadilla who contributed in the analysis of the results of the preliminary study in this dissertation, and for all the helpful discussions.

Lastly, I would like to thank all my family. My parents Enrique and Ivonne and my sister

Carina, for all their love and for always supporting and cheering every decision that I have taken. Most of all I would like to thank my wife Gabriela, because without her help and support this work would not have been possible. She has not only encouraged and advised me in every decision; she also helped me during the field research and has accompanied me in every step of this process. Finally, to our son Leonardo who has been our motor and everyday inspiration.

ABSTRACT

The patterns that have determined the building traditions in Mexico have transformed through-

out time. Before the 20th century, climate and local physical and socio-cultural conditions played a primordial role in their development. However, due to different reasons, but mainly because of the fast and uncontrolled growth of settlements and the predominance of a specific sector of the building material industry, the vernacular influence was left behind. The purpose of this research is to assess the reasons and consequences of such transformation within the housing sector.

As background, the development of building traditions in the country is examined in relation

to the climate. The analysis of the main factors that have shaped them since the first settlers until today gives a general overview of the raised problem. A preliminary study displays the importance of building 6

materials in this context. The intention of the study, which was carried out through an online questionnaire is to understand the publicâ&#x20AC;&#x2122;s preference of building materials in the country and the factors that have more influence over their decisions while choosing them.

For the main section of the research, two case studies were selected to give an example of two

regions in the country, which developed by following different patterns. One of them is the Monterrey Metropolitan Area (MMA) with a semi-arid climate, and the other is the Istmo de Tehuantepec (IT) in Oaxaca with a tropical climate. After a contextual analysis, six contemporary housing constructions with notorious vernacular characteristics and three conventional cement-based constructions were assessed per case study through field research. Their thermal performance was measured during extreme conditions in summer. The effects on the comfort and quality of life of the inhabitants were evaluated through surveys and interviews. The information was complemented through mappings, observations and architectural drawings.

The most significant findings display that the indoor and outdoor conditions remained mostly

out of comfort ranges in both, the vernacular and conventional cases. However, the overall perception of the inhabitants concerning their comfort and quality of life was significantly more positive in the vernacular typologies, which was mainly associated with the sensation of freshness and a relation to nature in both of the case studies. The results also demonstrate no significant difference between socio-economic groups in relation to the house and their quality of life. Nevertheless, in relation to the neighbourhood the most influencing factor in the MMA was associated with security and in the Istmo region with social relations, which is at the same time reflected in their architecture and urban configurations.

Moreover, the results show a positive response from the users toward environmentally sus-

tainable solutions in architecture regardless of location, housing type, or socio-economic background. Therefore, the results also reflect a conscious reaction to the vernacular influence and the benefits that such building traditions might have over the environment, but also over the comfort and life quality of the users in the future.

TABLE OF CONTENTS

ABSTRACT

1. INTRODUCTION

1.1

DEFINITION OF TERMS

1.2

THE STRUCTURE OF THE DISSERTATION

1.3

THE PROBLEM: THE LOSS OF LOCAL BUILDING TRADITIONS

1.4

EXISTING LITERATURE

1.5

THE QUESTIONS AND THE METHODOLOGY

INTERPRETATIVE - HISTORICAL ANALYSIS

MEASUREMENTS AND SURVEYS

QUALITATIVE INTERVIEWS

2. BACKGROUND: THE DEVELOPMENT OF BUILDING TRADITIONS IN MEXICO

2.1

PRE - COLONIAL ERA

2.1.1 ARIDOAMERICA

THE CLIFF SETTLEMENTS

THE OPEN SETTLEMENTS

2.1.2 MESOAMERICA

THE OLMEC CULTURE

THE MIXTEC AND ZAPOTEC CULTURES

THE MAYAN CULTURE

THE AZTEC CULTURE

2.2

SPANISH COLONIZATION

THE SPANISH CITIES

THE HACIENDAS

THE INDIAN TOWNS

2.3

19TH AND 20TH CENTURIES

THE GROWTH OF URBAN SETTLEMENTS

64 67

THE CEMENT ERA

2.4

THE REVIVAL OF VERNACULAR BUILDING TRADITIONS

21ST CENTURY

THE SOCIO - ECONOMIC DISTRIBUTION

THE SEARCH OF SUSTAINABLE SOLUTIONS

A PRELIMINARY STUDY ON BUILDING MATERIAL PREFERENCE

2.5

THE STUDY

THE RESULTS

THE CONCLUSIONS

3. CASE STUDIES: HOUSING ANALYSIS ACCORDING TO SOCIO - CULTURAL FACTORS, 100 SITE, CLIMATE, MATERIALS, AND TECHNOLOGY

3.1

THE STUDY

DEFINITION OF THE CASE STUDIES AND SAMPLES

THE FIELD RESEARCH

3.2

CASE STUDY 1: SEMI -ARID CLIMATE: MONTERREY METROPOLITAN

102 103 104 107

AREA, NUEVO LEON

3.2.1 SOCIO - CULTURAL CONTEXT

109

SECURITY AND CLOSED STRUCTURES

110

EXTERNAL INFLUENCE AND PROGRESS

116

121

3.2.2 SITE AND CLIMATE

BUILDING ADAPTATION TO THE SITE AND CLIMATE

125

3.2.3 CONSTRUCTION MATERIALS AND TECHNOLOGY

133

NATURAL RESOURCES, BUILDING MATERIALS, AND TECHNIQUES

135

MATERIAL INDUSTRY AND MARKET IN THE 21ST CENTURY

141

3.2.4 GARCÍA

147

HOUSE 1

148

HOUSE 2

152

HOUSE 3

156

3.2.5 MONTERREY

161

HOUSE 4

162

HOUSE 5

166

HOUSE 6

170

3.2.6 SANTIAGO

175

HOUSE 7

176

HOUSE 8

180

HOUSE 9

184

188

3.3

CASE STUDY 2: TROPICAL CLIMATE: ISTMO DE TEHUANTEPEC, OAXACA

3.3.1 SOCIO - CULTURAL CONTEXT

189

INDIGENOUS, SPANISH, AND EXTERNAL INFLUENCE AND RITUALS

191

COMMUNITY, COMMUNALITY, AND SEMI - OPEN STRUCTURES

197

205

3.3.2 SITE AND CLIMATE

BUILDING ADAPTATION TO THE SITE AND CLIMATE

209

EARTHQUAKES AND STRUCTURAL KNOWLEDGE

215

217

3.2.3 CONSTRUCTION MATERIALS AND TECHNOLOGY

NATURAL RESOURCES, BUILDING MATERIALS, AND TECHNIQUES

218

MATERIAL INDUSTRY AND MARKET IN THE 21ST CENTURY

221

3.3.4 TEHUANTEPEC

227

HOUSE 10

228

HOUSE 11

232

HOUSE 12

236

3.3.5 JUCHITÁN

241

HOUSE 13

242

HOUSE 14

246

HOUSE 15

250

3.3.6 ASUNCIÓN IXTALTEPEC

255

HOUSE 16

256

HOUSE 17

260

HOUSE 18

264

4. RESULTS: THE EFFECTS OF THE VERNACULAR INFLUENCE ON THE USERS

268

271

4.1

CHARACTERISTICS OF THE HOUSES AND THE INHABITANTS

MONTERREY METROPOLITAN AREA

273

ISTMO DE TEHUANTEPEC

275

277

4.2

COMFORT 4.2.1 RELATION OF RESULTS BETWEEN ARID AND TROPICAL CLIMATES

279

4.2.2 RELATION OF RESULTS BETWEEN VERNACULAR AND

283

CONVENTIONAL TYPOLOGIES MONTERREY METROPOLITAN AREA

283

ISTMO DE TEHUANTEPEC

287

292

4.3

QUALITY OF LIFE 4.3.1 RELATION OF RESULTS BETWEEN INHABITANTS ACCORDING

293

TO SOCIO - ECONOMIC SEGMENTATION MONTERREY METROPOLITAN AREA

293

ISTMO DE TEHUANTEPEC

298

4.3.2 RELATION OF RESULTS BETWEEN INHABITANTS ACCORDING

303

TO VERNACULAR AND CONVENTIONAL TYPOLOGIES

MONTERREY METROPOLITAN AREA

303

ISTMO DE TEHUANTEPEC

305

308

4.4

SUSTAINABILITY

MONTERREY METROPOLITAN AREA

309

ISTMO DE TEHUANTEPEC

311

314

4.5

THE FINDINGS

MONTERREY METROPOLITAN AREA

315

ISTMO DE TEHUANTEPEC

319

CONCLUSIONS

323

5. CONCLUSIONS: WHY SHOULD WE APPLY VERNACULAR BUILDING TRADITIONS IN 326 TODAYâ&#x20AC;&#x2122;S ARCHITECTURE?

EXPECTED CONTRIBUTIONS

331

FUTURE RESEARCH

334

6. LIST OF REFERENCES

338

7. LIST OF FIGURES

348

8. LIST OF TABLES

352

9. APPENDIX

353

I. PRELIMINARY STUDY: BUILDING MATERIAL PREFERENCE QUESTIONNAIRE

II. COMFORT AND LIFE QUALITY SURVEY

1 INTRODUCTION

CONTEXT THE DEVELOPMENT OF BUILDING TRADITIONS IN MEXICO

1.1

DEFINITION OF TERMS

VERNACULAR When speaking about â&#x20AC;&#x153;vernacularâ&#x20AC;?, one may think of something from the past, but in reality, it may refer as well to something related to the present or the future. From its etymology vernacular, from the Latin, means native to a place and was mainly used for languages (Harper, 2017). It was until later that it was used in other disciplines like arts and architecture. Therefore in architecture, it refers to constructions that are adapted to a place, built with building techniques suited to local materials and reacting to local conditions. It is not to be confused with architecture built without architects as proposed by Bernard Rudofsky (1964), as vernacular architecture can be design by anyone, hopefully, architects as well. The reason that it is seen as something from the past is that usually architecture before used to respond to the immediate context, resulting in a local building tradition. With territory invasions and the mix of different cultures at first, then with the industrial revolution and lately with raise of globalization, the idea of vernacular has been left behind, giving space to conventional designs, materials and styles. Nevertheless, the influence of the native, the autochthonous: the vernacular can still be found in many of the contemporary constructions, which in the cases of this thesis refers to constructions from the 21st century.

Fig. 2

Rural landscape in Nuevo Leon. Taken by author

Climate Tropical Wet and dry (Aw) Rainforest (Af) Monsoon (Am) Arid Hot desert (BWh) Hot steppe (BSh)

Fig. 3

Kรถppen-Geiger classification world map. Made by the author with information from Peel, Finlayson, &

McMahon (2007)

BUILDING TRADITIONS Since most the population spend most of their lives within residential-use constructions, this study will be based on housing typologies. It is also the first building typology that existed, because of the human necessity of dwelling. It, therefore, accounts for the most significant proportion of buildings worldwide. So when the concept is addressed within the text, this study is referring mainly to the ones related to residential use. Moreover, the term “tradition” can be taken from its etymology denoting a practice that has been handed down from generation to generation (Harper, 2017). It is therefore defined by culture, and it can be autochthonous, imposed, or it can be taken from somewhere else, but it stays in a place for an extended period of time. When the two terms are combined, they refer then to specific building techniques and styles that have been used in residential constructions through different generations.

HOT CLIMATES According to the Köppen-Geiger climate classification, the most widely used worldwide, hot climates belong to two different groups: the tropical and the arid climates. These climates are characterized by having an annual average temperature higher than 18 °C. In broad terms, the first group is characterized by having higher levels of humidity and rain, while the second has dryer periods and less humidity (Newman, 2002). These climates are mainly located in countries that are between or close to the tropics, including regions of Central and South America, Africa, South Asia and Oceania (figure 3). This classification was based on the weather conditions that match the soils and vegetation of the Earth and therefore are also a reference of the ecosystems and the available natural resources. The groups and sub-categories that integrate the hot climates are:

group A: Tropical/mega thermal climates Tropical wet and dry climate (Aw) Tropical rainforest climate (Af) Tropical monsoon climate (Am)

group B: Dry arid and semiarid climates Hot desert climate (BWh) Hot steppe climate (BSh)

1.2

THE STRUCTURE OF THE DISSERTATION

1. Introduction | The Influence of the Vernacular

This research is organized in five chapters. The first chapter gives an introduction to the

subject. The most important terms used throughout the dissertation are defined. Then, the main problem that the study is confronting is presented, which is the partial loss of vernacular building traditions and some of its consequences. Following, the main existing literature that has been focused on the same problematic since the past century is discussed. Most of this framework is focused on the topic of regionalism and on publications that have similarly studied the contextualization of typologies within a specific culture and climate. However, a complementary approach is proposed to address the research gap. This chapter, therefore, also contains the methodology and the research questions that will be answered with the different steps of the study.

The second chapter gives a chronological background of the development of building tra-

ditions in Mexico. The most representative studies on the subject concerning the climate and the inhabitants, which include archaeological and socio-cultural findings, are presented. The general socio-economic situation is also described, as it is one of the main variables in which the research is based for comparison. Given the lack of existing graphical information on the topic, the research

is complemented with own interpretations depicted in the form of mappings and architectural drawings. The last section of the chapter is a preliminary study on the subject of building materials, as they represent one of the most critical factors that define the vernacular and conventional building traditions.

In the third chapter, the two case studies, which serve as examples to answer the main re-

search question are presented. In the first section of the chapter, the explanation of the main study and the methodology that were followed are further extended. Then, each of the case studies is analysed in terms of their socio-cultural context, their situation in the landscape and the climate, and according to the availability of materials and technologies. The information is concluded by interpreting existing texts and mappings, and through interviews with stakeholders in the communities. Then, the information from the nine typologies that were measured and analysed during the field research is summarized in the form of architectural drawings, the description of the interior and exterior conditions and through observations.

The fourth chapter displays the results of the comfort survey and the qualitative inter-

views that were carried out with the inhabitants of the 18 houses. The results are compared between the two case studies, and they are also analyzed in relation to socio-economic segmentation, and type of construction: vernacular or conventional. The results of a follow-up question on the topic of sustainability are also presented as a complement of the preliminary study, and as a prelude to the conclusions. Finally, in the fifth chapter, the conclusions and expected contributions, as well as suggestions for future studies on the subjected are established.

1.3

THE PROBLEM: THE LOSS OF LOCAL BUILDING TRADITIONS

1. Introduction | The Influence of the Vernacular

Nowadays, new constructions are often designed and built without considering the differ-

ent climates, the physical conditions and the local cultural context of their locations. That has not only led into repercussions to the energy consumption during the buildingÂ´s lifespan, but it has also affected the comfort and life quality of its users. A way to address this problem is to look into the local building traditions that have survived throughout the years before they are lost before they fade within the conventional building solutions that prevail in architecture today. In that sense, we must look back and learn from vernacular architecture. It might be necessary to move back to pre-industrial times to learn how to achieve a balance, but the real challenge is to move forward to achieve this goal (Hyde, 2008).

The industrial revolution marked a turning point in the partial loss of local building tra-

ditions, as cheap fossil fuels allowed new materials like steel, cement and glass to be developed. It also became much more accessible to transport those materials. The import of goods proliferated and paralleled to the import of styles and designs. The search for comfort modified as well the built environments, as mechanical heating and cooling systems, replaced passive solutions in buildings.

Regardless of the location of a construction, it was easier to keep a space warm or cold, so people could stop paying attention to the natural means of doing it, with the aid of the sun and natural ventilation. That allowed architects and builders, in general, to copy designs and apply the same materials and technology from place to place, creating a new building tradition.

Amos Rapoport (1969, p. 6) explained the loss of tradition as a regulator because of three

reasons.

“The first reason is the greater number of building types, many of which are too complex to build in traditional fashion… The second reason is the loss of common shared value system and image of the world, with a consequent loss of an accepted and shared hierarchy and generally a loss of goals shared by de-signers and the

public. This results in the disappearance of that spirit of cooperation, which makes people respect the rights of adjoining people and their buildings, and ultimately the right of the settlement as a whole… The third reason for the disappearance of tradition as a regulator is the fact that our culture puts a premium on originality, often striving for it for its own sake. As a result, society becomes dissatisfied with traditional forms, and the vernacular process can no longer work.”

The limitation of searching for local answers started to vanish, and global trends started

to shape our lives, and it has become a constant until today. That brought first questions mainly on identity, on the importance of keeping local traditions as part of social and economic development of a place. However, it then became also a central question on the search of solutions for climate change and the sustainability of our world. We realized that we clearly do not have enough resources and fossil fuels to continue with this pace and that the building sector has become one of the main contributors to this problem. This dissertation is written in a time when the United Nations and the World Meteorological Organization warn us about the repercussions that our actual life-style can have on the future of our natural and physical environment, having as a reference the pre-industrial temperature levels (Ipcc, 2018). Therefore, this study in-tends to give a possible solution within the building sector, which is to look for the influence that vernacular building tra-

ditions might have in contemporary architecture and how can this contribute to a low-energy and low-carbon architecture.

Unfortunately, there are many social barriers to sustainable development in architecture.

There have been significant technical and economic advances regarding this matter, nevertheless, the adoption of practices in construction remains low (Hoffman & Henn, 2008). Therefore, the aim of this research is not only to display the ecological benefits of applying vernacular principles, which has been widely studied but also to analyze the social factors that affect the decision-making process in its application and the social benefits that come after their construction. Further on, the goal is to asses built case studies where vernacular principles have been implemented to understand the conditions within a specific context. Also to create a research framework that could be repeated in other countries to study the influence that the vernacular has had in the contemporary architecture and the comfort and life quality of the users in different locations.

1. Introduction | The Influence of the Vernacular

1.4

EXISTING LITERATURE

There have been several researchers, theorists and practitioners that have address the

problem of losing local building traditions in architecture. Probably some of the first thoughts on the topic came together with modernism. On a time when an international style was promoted within architecture schools around the world, the topic of regionalism and the sense of place gained importance, as a response to the loss of identity in architecture. The written work of Lewis Mumford (1941), Paul Ricoeur (1965), Christian Norberg-Schulz (1980) and Juhani Pallasmaa (1988) were some of the most influential that attacked these questions. There were also architects that tried to address it in some way in their buildings like Alvar Aalto, Aldo van Eyck and even Le Corbusier. In Mexico, probably the most well-known example is Luis Barragan, who contextualized the international style into the Mexican landscape with the use of colors, courtyards and nature, taken from local cultural traditions.

One of the first architects to emphasize the importance of climate and local building ma-

terials in architecture was Hassan Fathy. His work demonstrates how useful passive design principles can be in the development of feasible solutions in contemporary architecture in the Arab

region (Fathy, 1986). His work also came on a time when the ideals and practices of modernism were questioned, and his ideas influenced the discussed topic about regionalism in architecture. Within the same context, Victor Olgyay (1963) published his book “Design with climate: bioclimatic approach to architectural regionalism”, where he defined different strategies to follow by the architect during the decision-making process depending on the measured meteorological data of a specific location. This approach was followed and extended later on by a number of scholars including B. Givoni (1969) and M. DeKay & G. Z. Brown (2013), among the most prominent. Lately, different scientific publications addressed these methods to underline the importance of defining bioclimatic design concepts and strategies after learning from vernacular cases. Authors like Carrazco (2004), Manríquez, Fuentes & Guerrero (2006), Omer (2008) and Sourbon & Helsen (2011) contributed to this topic.

There have also been several scholars that have worked over a historical-interpretative

approach by analysing typologies that appeared with specific regions and were part of a vernacular building tradition. Some of this research, such as the compilation of vernacular architecture by Oliver (2003), Rapoport (1969), and by Weber & Yannas (2014), can serve as a base to understand the

1. Introduction | The Influence of the Vernacular

physical and cultural factors connected to a specific typology. In addition, there are organizations such as ICOMOS or the Society of Architectural Historians that have focused on the preservation of heritage and also the study of such typologies. More recently the subject has been treated in the book “Habitat: Vernacular architecture for a changing planet”, where Sandra Piesik (2017) increases this compilation of typologies dividing them by climates, but as well includes a section with examples of contemporary architecture, underlining the importance of the adaptation of local or regional knowledge into today’s situation.

According to Lindsay Asquith and Marcel Vellinga (2006), there has been an increasing in-

terest in studies that document a specific building tradition (mainly non-western) within a regional context. In Mexico, there has been a research community dedicated to the study of vernacular forms and bioclimatic architecture in the region. The studies from V. Prieto & S. Carrillo (1978), V. Fuentes & M. Rodríguez (2006) and G. Torres Zarate (2009) show examples of architecture that is built as a reaction to the local and climatic conditions. They also explain how can these typologies improve the comfort and in a way the life quality of their users. That contributes to a growing net-

work of researchers and practitioners in the country that are searching to bring back the values of local building traditions in an effort to achieve low energy architecture, but also to shape a local identity again.

The majority of the studies are focused on a specific typology of vernacular architecture

and the qualities of such constructions, so they are based on interpretative-historical research (Groat & Wang, 2002). Nevertheless, there is a lack of scientific information on how to translate those qualities into contemporary architecture. Therefore, there lies an opportunity to research on the specific influence on how this learning has been applied as good-practice in later times and on how the design strategies from vernacular building traditions can still be used to achieve a more sustainable architecture in the future. Besides, most of the existing studies, even though they achieved their purpose, do not take the users into account, but rather physical and typological analysis based on empirical data. Therefore, a way to address the subject is to use a mixed methods approach, where a historical interpretation is made, experimental data is acquired, but also an indepth analysis of the users is included. In that way, we can better understand the social conditions that lead to a particular building tradition and the consequences that this can bring in terms of comfort and life quality. The specific research questions and the methodology to do so will be explained next.

1.5

THE QUESTIONS AND THE METHODOLOGY

1. Introduction | The Influence of the Vernacular

This study was carried out with a mixed methods design, having as a base a multiple case

study approach. Within the different case studies, quantitative and qualitative strategies were used to answer the research question:

How can the influence of the vernacular be identified in contemporary architecture and how does it affect the users in hot climates?

In order to give an answer to the primary research question, two different case studies

were chosen in Mexico: one with semi-arid climate and one with tropical climate. For the arid climate, the case of the metropolitan area of Monterrey in the state of Nuevo Leon was analyzed. For the tropical climate, a region called Istmo de Tehuantepec in the state of Oaxaca was selected. These locations were chosen given their importance in the national context and because their territory includes regions with the different climate subcategories. These are states that are not only

distinct because of their climate, but they also have a relatively different culture, which is related to their geographical position in the country and to their economy. The focused was then on three municipalities that corresponded to different climate subcategories or areas with high socio-economic contrast in each of the case studies.

Within the case studies, different housing typologies were chosen to demonstrate the ex-

tent of the vernacular influence in todayâ&#x20AC;&#x2122;s architecture. Three housing samples and its users were analyzed in each municipality. In total, eighteen single-family houses and their users were analysed with a mixed methodology design, combining qualitative and quantitative approaches. In relation to the mixed methodology approach, L. Groat and D. Wang (2002) suggest that it represents the most complete level of integration among two or more research designs. The advantage of such approach is that the strengths of each research design can complement each other, while the weaknesses of each design can be substantially offset. Three methodological steps were primarily used. The first was an interpretative-historical analysis conducted in the context of the Mexican territory and then in each of the case studies. The second was comfort measurements and surveys that were performed in each of the samples. Finally, qualitative interviews were carried out with the users to investigate the factors that most significantly influence their quality of life. The different steps were based on sub-research questions.

INTERPRETATIVE-HISTORICAL ANALYSIS

How have vernacular building traditions been applied in contemporary constructions in Mexico and in the case studies?

To better understand the development of building traditions, a historical analysis was first

done in Mexico as a contextual approach to the subject. Self-interpretation was mainly reflected in mappings and drawings that accompanied the written description. The analysis of the national context and a preliminary questionnaire-based study that was performed nationwide served as a prelude to the main study. The interpretative-historical analysis was then focused on a regional

scale. The natural and socio-cultural contexts in relation to their building traditions were examined in detail for each of the case studies. The information was supported with interviews with the community and with further regional mappings, some of them elaborated with the aid of the geographic information system (GIS) from Nuevo Leon and Oaxaca. The mappings served as a base for determining the extent of the field research. Finally, the interpretative-historical approach was focused on a typological scale for the physical analysis of the houses, mainly through architectural drawings, photographs and interviews with the inhabitants.

MEASUREMENTS AND SURVEYS

How has the vernacular influence affected the comfort of the users of the selected houses in the case studies?

1. Introduction | The Influence of the Vernacular

One of the factors that affect the life quality and that is in a significant part determined

by the design of a building is the comfort and indoor environment quality (Soares, Fraga, Delgado, & Ramos, 2015). Therefore, simple measurements and surveys in each of the housing samples were performed to analyse deeper this important hygrothermal aspects and their effect on the users. The physical aspects to relate between the interior and exterior of the dwellings were air temperature, surface temperature, relative humidity, illuminance and air velocity. The overall comfort satisfaction of the occupants, their usual behaviour in the house, and the reaction to uncomfortable conditions were also evaluated through a survey. The measurements and the surveys were performed during summer, as it is the critical season in hot climates when the environmental conditions are out of the comfort ranges, and a more significant dissatisfaction of the users can be expected.

QUALITATIVE INTERVIEWS

How has the vernacular influence affected the quality of life of the users of the selected houses in the case studies?

There have been several studies that tried to find indicators to define a personâ&#x20AC;&#x2122;s quality

of life, a topic that has become primordial in the sustainable planning discussion. Nevertheless, there is still no accepted framework or system to evaluate its relation to the built environment (van Kamp, Leidelmeijer, Marsman, & de Hollander, 2003). That is why parallelism between the qualitative and quantitative factors is essential. In that context, for the qualitative research, structured interviews were conducted. The aim was to understand their perception towards their life quality and to see in what extent the architecture and the surroundings of their house affected this quality. In that sense, the comfort questionnaire was extended to include open-ended questions that added the qualitative approach to the study. The results of the surveys and the interviews were analysed according to socio-economic segmentation and to typology: vernacular or conventional. The results also intend to give an answer to the last sub-research question:

Why should we apply vernacular traditions in todayâ&#x20AC;&#x2122;s architecture?

2 BACKGROUND

THE DEVELOPMENT OF BUILDING TRADITIONS IN MEXICO

CONTEXT THE DEVELOPMENT OF BUILDING TRADITIONS IN MEXICO

Even though the local building traditions have to be understood per region, there is a

general cultural context that can be explained within the limits of the whole nation, and that is greatly dependent on several social and natural conditions of the territory. For thousands of years, its inhabitants were nomadic groups of hunter-gatherers that adapted to different ecosystems. With time, some of the groups adopted agriculture, as the primary means of subsistence and with that the definition of two areas: Aridoamerica and Mesoamerica. The first one located on the North of Mexico, predominated by arid climates, kept the groups of nomadic character. The second one, with tropical and temperate climates, is where the most important ancient civilization flourished (Solanes Carraro & Vela RamĂrez, 2000). This division marked the first clear definition of building traditions in Mexico.

The second important event that transformed the building traditions in the territory was

the Spanish colonization (1521-1810 AD). The cultural imposition was very much reflected in architecture. The import of new materials, technologies, typologies and even ideologies affected in many ways the building culture from that time; nevertheless it was adapted in many cases to the local natural and social conditions of each town or region. The class and socio-economic division started to become more differentiated concerning building practices during this period. Domestic spaces began to reflect the aspirational character of the builders and residents towards European standards. A distinction between the most luxurious palaces and the most humble shacks was usual to identify society (Beezley, 2011). This classism where the European or foreign lineage is seen as superior is common until nowadays and has remained as one of the main parameters that define the building traditions in the country.

The next vital transformations of the building traditions in Mexico occurred in the 19th

and 20th century with different kinds of revolutions. After Mexicoâ&#x20AC;&#x2122;s war of independence (18101821 AD), the ideals of converting the country into a prosperous nation were baffled by decades of internal conflicts, political disorder, and invasions, generating countless population loss and economic recession in most parts of the country. The country lost almost half of its territory to the United States and was ruled for several years by the French (MCCAA, 2000), who were expelled only to be ruled by Porfirio Diaz, a dictator who was overthrown by the Mexican Revolution. The main consequence of those years of war in relation to the building dynamics was the social segregation

Fig. 4

Paquime (I. Merodio, 2008)

and the uneven distribution of land and resources that benefited just a few. The democracy that followed for the rest of the 20th century was led mainly by the elite, which as explained by Luis E. Carranza (2010) kept an economic development based on the exploitation of the working class. All of this in combination with the search of modernization started to shape the distribution and image of cities and towns, guided by the private sector, public housing programmes and informality.

Parallel to the tremendous social and political changes in the country, the population had

to deal with another type of revolution. As in many parts of the world, the industrial revolution affected in many ways the building sector. This was the time where the vernacular traditions started to change or disappear through the influence of modernization. The revolution of building materials came first with the production of materials with high-embodied energy like steel, glass, and concrete, which started to shape the building dynamics. Then, the 20th century was distinguished by the proliferation of industrial systems and mass production (T. Smith, 1993), where cheap fuels, labour, and materials, mainly cement, were primordial to keep up with the rapid growth of population and construction in the country. The mentality of growing without limits was acquired by various groups of the population that saw the United States as the role model to imitate (Carranza,

2. Background | The Influence of the Vernacular

2010). An ideology flourished, where material possessions and housing define social status. This, of course, had a significant impact on the way settlements expanded, on peopleÂ´s behaviors and their philosophy towards quality of life and comfort.

In general, the architecture of the 21st century in Mexico has followed the patterns from

the past century, where the climate is not considered, where cheap and high-embodied-energy materials are preferred, where buildings are defined by socio-economic status and where the foreign is more embraced than the local. Nevertheless, there is a tendency to change this position towards more sustainable solutions. However, in order to understand the influence that vernacular building traditions have in contemporary architecture, the main physical and cultural factors that have influenced the building traditions in Mexico until today have to be considered. This chapter collects those key elements to serve as a general contextual overview to grasp the main common aspects of the historical conditions of the case studies. In addition, it provides examples of passive design strategies and building techniques from typologies that were developed in hot climates and that are adapted to their specific location.

2.1

PRE-COLONIAL ERA

Most of the architectonic history from the pre-colonial era and during early times from

the Spanish colony is documented only through Archaeological findings. So the record that we have of the constructions is based many times on hypotheses made by the archaeologists and historians after the excavations and analysis of a specific site, and therefore they should be taken with care, as they represent a subjective perspective. One of the most important texts, for example, was written in the 16th century by Fray Bernardino de Sahagun and was called â&#x20AC;&#x153;General History of the Things of New Spainâ&#x20AC;? where he described many of the pre-colonial settlements. However, there is a lack of information related to specific aspects of the constructions. In other cases, the authors who documented the findings were more interested in religious, military or civic characteristics of the culture (GarcĂa Targa, 2006). That happened because many of the constructions that survived through time were dedicated to such uses and there is not as much documented history about residential use constructions. Mainly, because they were built with materials that degraded faster, so they had a shorter lifespan. Nevertheless, there have been findings that demonstrate the main building traditions of certain periods that have transcended through time and that have influenced architecture until today.

Aridoamerica

Mesoamerica

Climate Tropical Wet and dry (Aw) Rainforest (Af) Monsoon (Am) Arid Hot desert (BWh) Cold desert (BWk) Hot steppe (BSh) Cold steppe (BSk)

Fig. 5

Arid and tropical climates in Mexico. Made by author with information from GarcĂa (2004)

200 km

The territory where Mexico stands today was culturally divided into two distinct areas de-

fined by Paul Kirchhoff for their study. The first, Aridoamerica, extends to the north of the country and to the south of what today is the United States of America. There, we mainly found nomadic societies due to the extreme characteristics of the arid climates that could not settle mainly due to the lack of water and the variations of high and low temperatures. Nevertheless, there were also sedentary societies in a small area that was denominated Oasisamerica where the existence of water made cultivation possible. The second zone is Mesoamerica, which mainly comprises the tropic zone and where most of the sedentary cultures established. As can be seen in figure 6, cultural differentiation was mainly motivated by the rainfall and humidity regime. Even though these cultures had to deal sometimes with the problem of having too much rainfall and floods, the tropical climate favors the adaptability of human beings and the obtaining of natural resources for their survival (Amador, 2008). The following description gives a subjective selection of what could be considered the main cultures that established in Mexico and the most representative building traditions within arid and tropical climates.

2.1.1 ARIDOAMERICA

As earlier explained, this region was mainly defined because the hot arid climates pre-

dominated, which made it difficult for sedentary settlements to establish. These climates are characterized by hot days and colder nights with low levels of precipitation. The high temperatures at day cause low humidity, generally between 10 and 30%. As temperatures drop at night due to the rapid radiation loss, the humidity rises. Nevertheless, the precipitation is irregular and not reliable (Gabler, Petersen, Trapasso, & Sack, 2008). The small amount of recorded pre-colonial architecture in this region tended to respond to the extreme climatic conditions. Due to these conditions, such regions were only inhabited with a tiny fraction of the population, which was mainly nomad (Ooi, 1993). The low population can explain the small number of built vernacular examples that can still be studied. Nevertheless, these examples have demonstrated how thermal comfort could be achieved in such climates.

Anasazi

Mesa Verde

Chelly Canyon

Chaco Canyon

Oasisamerica Pueblo Grande

Castillo de Montezuma Mesa Grande Gila Cliff

Hohokam

Casa Grande Morollon

Trincheras

Paquime Cueva de la Olla Cueva Grande Huapoca

Cuarenta Casas

Aridoamerica

Chichimecas

Mesoamerica Tenochtitlan

Chichen Itza Mayapan

El Tajin

Coba Totonaca

Aztec

Olmec La Venta S. Lorenzo Zapotec Mixtec Monte Alban Guiengola Tututepec Tehuantepec

Mayan Palenque

Tikal

Main Cultures Important settlement

Copan

Mesoamerica Mayan Olmec Zapotec Mixtec Totonaca Aztec Aridoamerica Chichimecas Morollon Hohokam Anasazi

Fig. 6

Main cultures that developed in Aridoamerica and Mesoamerica. Made by author with information from

Alchetron (2019) and Fernรกndez Lรณpez (2018)

200 km

According to Carrillo Cázeres after a text by Fray Guillermo de Santa María (2003), the no-

madic tribes that lived in the North of Mexico were named Chichimecas by the Spanish colonizers that found them in the 16th century. Apart from some writings that described them, there are only a few physical traces of their way of living. They were warriors and hunter-gatherers who lived mainly in caves and didn’t have a developed culture, in comparison to the inhabitants of Mesoamerica. Another critical difference is that they did not have any religious rituals, which in the case of Mesoamerica was one of the primary parameters in the definition of their culture and therefore their architecture.

In contrast, in the region known as Oasisamerica, there are still several archaeological

sites that reflect the establishment of more developed cultures. Even though there are some variations between the archaeological sources, the most important and commonly cited are Anasazi, Morollon, and Hohokam. They have found several aspects that differentiate them from one another like their rituals, tools, and ceramics; nevertheless, they have all similarities when comparing their building traditions. They all developed two types of settlements with some variations: the ones that were dug into cliffs or used existing caves on mountain bases and the ones that were built using the earth and stones of flat plateaus and built on top. As the majority of the vernacular architecture around the world, the materials of the constructions were chosen depending on availability. As these cultures developed surrounded by deserts, three materials became the principal source for the constructions: sandstone, clay and in fewer quantities wood.

The first type of settlement, the cliff dwellings as they are commonly referred, were devel-

oped mainly in canyons where the inhabitants were naturally shadowed and some-how protected from the harsh conditions of the desert and the neighbouring tribes. Within these types of structures, there were also two types of constructions that are linked to the building traditions of the cultures that built them. The Anazasis and Hohokams used mostly masonry for the walls, and the Morollons used cob technique (Gamboa Carrera & Gutierrez Vacío, 2016). However, many similarities led to conclude that there was significant influence between one another like the distribution of the dwellings, the partition walls, the slab and roof systems and the shape and proportion of the openings.

THE CLIFF SETTLEMENTS

Examples of cliff dwellings where masonry was used can be found in Mesa Verde, Chelly

Canyon, Gila Cliff and Castillo de Montezuma. This building technique was developed over the years, first with one stone thick walls that used a large proportion of clay mortar and could not support more than one story. Then, with two and three layers of stone, which allowed them to have higher construction. Finally, they improved into compound walls with a core of rubble and mortar and two layers of stone veneer by side that used fewer mortar joints. The width changed depending on the story, but they had up to 60 cm at the base. Sometimes stone buttresses were added to provide even more stability (Schreiber, 1997), which not only permitted more stories, but it also provided high thermal mass that enhanced the thermal comfort of the dwellings. In some cases, the walls were furthered covered

Similar examples where cob technique was used instead of masonry to build the walls can

be found in Cuarenta Casas, Cueva Grande, Cueva de la Olla and Huapoca. This technique consists

2. Background | The Influence of the Vernacular

of piling thick mud stabilized with natural vegetable fibers with the hands, placing it on a row and then doing the same on top until forming a wall. Depending on the height, the walls had a thickness from 40 to 120 cm (Brown, 1998). In some of the caves they incorporated stones into the mud mixture and in other cases they built-in wooden posts that allowed them to reduce the thickness of the wall. It can be inferred that the heavyweight envelope had an excellent insulation value and high thermal mass. Due to the technical development of this type of walls, and the extreme climate conditions, the openings were relatively small. All of the mentioned sites were located on a 50 km radius close to each other; they were related and therefore shared building traditions with one of the main settlements from that time, which was called Paquime.

In both cases, many partition walls were made with bajareque a technique that consists

of a series of sticks or reeds that are interwoven and the covered with a layer of clay mortar. This technique is much lighter than the stone or rammed earth walls, and therefore was used to reduce loads in the constructions. Also for the construction of the ceilings and roof, the same technique was used in both cases. They used mainly pinewood, which was often brought from up to 70 km

Fig. 7

Construction section of a typical cliff dwelling. Made by author with information from Gamboa Carrera &

Gutierrez Vacio (2016)

scale 1:50

001.001.0.0 noisreVrehsilbuPSG

away. First, they placed the main layer of trunks supported on the walls, which regularly spanned not more than 3 meters; then a layer of reed or sticks in the other direction and above they poured a layer of clay mortar, which they refined until achieving a flat surface. The same applied at all levels, although sometimes the surface of the cave was used as a roof for the last level.

THE OPEN SETTLEMENTS

The second type of settlement was developed in extensive flat areas like plateaus and val-

leys, close to irrigated rivers or streams. This condition was probably related to a period with more stability where there was less conflict with nomadic groups, so the sites were more accessible to reach. It also generated an increase in population and a more advanced society. They started to develop more complex urban structures with plazas and kivas that were circular constructions where they performed rituals and religious ceremonies (Lรณpez Austin, Lรณpez Lujan, & Ortiz De Montellano, 2005). The materiality and building techniques that were used did not differ significantly with the previously mentioned. The use of stone and rammed earth remained similar, dependent on the culture.

2. Background | The Influence of the Vernacular

Some of the most studied examples of this type of settlements were built with cob as the

primary building technique, as seen in Mesa Grande, Pueblo Grande, Taos Pueblo, and Paquime, where the later was considered the most developed. Even though they shared building traditions with the cliff dwellings before mentioned, there were differences. One of them was the configuration. They had the advantage of not having limited space, so instead of building in a row, their rooms were arranged around a courtyard, which created colder microclimates. Another difference is that apart of using the cob technique for wall construction, they also introduced rammed earth (Bagwell, 2004). This technique consists of pouring layers of a mixture of gravel, sand, lime, and water into a wooden framework and compacting them every 20-30 cm until the desired wall height is reached. Most of the structures had one level, but some reached 4 or more levels. Even though they designed procuring solar gains, as these were minimal during the cold season in winter, they introduced the first heating systems from the region. In some dwellings, an oven was used to heat the buildings, and according to a study made by Hodgson, S. (2002), this was the first city to develop a geothermal heating system for most of the buildings. They also had advanced irrigation

Fig. 8 (1997)

Construction section of a typical dwelling from Paquime. Made by author with information from Schreiber scale 1:50

systems that allowed them to establish for a more extended period.

Examples of the same type of open settlements but built mainly with masonry were Gran

Quivira, Chetro Ketl and Pueblo Bonito. The two later have gained recognition, due to their size and complexity. As described by Schreiber (1997) in his study about the Anasaziâ&#x20AC;&#x2122;s engineering, they were built in a valley along the Chaco Canyon, where they took the limestone to build with. They used mainly the compound wall system with two types of limestone. The roofs for the dwellings used the same wooden system that was explained before, but they also introduced a different system for the round structures, which consisted of wooden beams that formed a hexagon perimeter, where the next layers were rotated and reduced in size to form a dome as it can be observed in figure 8. Another development that can be seen, as described with Paquime, is the clear relation to the sun. The orientation of the buildings became a primordial element in their planning, probably not only because of comfort reasons but also because of a whole cosmology that connected their inhabitants with nature.

2.1.2

2. Background | The Influence of the Vernacular

MESOAMERICA

Many of the dominant cultures from the pre-colonial era developed within tropical re-

gions. These areas are characterized by having high temperatures along the year during day and night. They also have high levels of precipitation, and therefore also high levels of humidity, which both of them can fluctuate depending on the sub-climate (Newman, 2002). The settlements were developed close to bodies of water like rivers, lakes and the ocean, so in many cases, they had to deal with floods and the excellent management of water. On the other hand, these climates also favored agriculture and the formation of tropical forests and rainforests, where they took their resources and the materials to build their dwellings, which were mainly: tropical wood, palm trees, clay and in less quantity stone. All these factors together with the search of comfort and the cultural aspects within the household started to shape the building traditions in Mesoamerica.

There were many similarities between the building traditions of each culture of the tropi-

cal regions. Many of their constructions from our imaginary are massive, stone pyramids and complex structures; nevertheless, these represent only a fraction of the life of that time. Those constructions were mainly dedicated to religious ceremonies, rituals and the governing class, but the rest of every-day life, where the settlements and dwellings were located, happened on the outsides of those sites. Unfortunately, in every case, they were built with perishable materials, so finding ancient dwellings that have not been affected by nature or by human activities is an unusual event. However, the documented examples suggest certain trends in materials, building techniques, size and distribution over time, presenting just some variations dependant on the culture (Solanes Carraro & Vela RamĂrez, 2000). Besides, many of the building traditions from that era, have survived by passing from generation to generation and they are still vivid until nowadays, representing an essential part of the vernacular influence in that region.

THE OLMEC CULTURE

The first culture to establish, and that nowadays is considered the mother of all civiliza-

tions of Mesoamerica was the Olmec Culture. The first inhabitants settled in strategic positions close to the rivers. In San Lorenzo, the first registered settlement, their houses were placed over rammed earth mounds and consisted of one rectangular room built with wood as the main structure, tied with fiber ropes. The walls were covered with reed, which was sometimes covered with mud (bajareque). The roofs were always covered with palm leaves. This typology represented the base of the housing building tradition of all the cultures that flourished in the tropical regions of Mesoamerica approximately between the 19th century BC and the 16th century AD. The reason to conserve a similar building tradition within different cultures for an extended period of time can have many explanations and can be interpreted in many ways, but it is undoubtedly correlated with the use of local resources concerning the needs of the society from that time.

Within the Olmec Culture, this typology was slightly transformed throughout time. The

social stratification gave the first notorious difference. Bigger houses were found on higher terraces on the hill, closer to the ceremonial sites, which probably belonged to the elite group (J. E. Clark,

1994). Those houses also had more rooms, and even though the materials were kept the same, there was a differentiation on the precision of the construction, which indicates skilled labor. The platforms of rammed earth from where the houses were erected began to have distinctions in levels, which speaks of a possible hierarchy of spaces. Later, another variation was introduced within that social group, which was the use of stone for the base of the house. Bentonite, basaltic rocks, and limestone were brought from the coasts to build terraces and low walls that kept the houses safer from floods and protected the bajareque walls from humidity. These technological improvements can be seen in later periods in La Venta and even within the neighboring Totonaca Culture in El Tajin, which shared very similar physical and social conditions.

In La Venta, a site that became the capital of the Olmec culture, archaeologists have found

evidence of what could be the first multi-family structures. The presence of domestic groups with larger buildings that show an internal division of space coincides with the increase in population density in the capital. The materials and building techniques were the same, but their internal differentiation reflects the functional differences and possibly status of the occupants. They are indicators of huge domestic groups (around 40 to 70 inhabitants) that on the terraces and top of

2. Background | The Influence of the Vernacular

the plateau and had a greater workforce than the nuclear families (Cyphers, 2016).

The renovation of the Olmec residential structures was typical in all of the social classes

and involved changes in their design and size to adjust to the greater or lesser needs of the inhabitants, following the family demographic cycle. As the villages grew, in some of them the family organizations sought-after expanding their size and labor force to increase their productive power; thus, the domestic unit expanded to group several nuclear or extended families, which include other relatives, as well as parents and children. This could be achieved by expanding the space of the room to accommodate more members, or by building new dwellings next to the existing, which generated a shared courtyard. The communities expanded then with sets of family territories, a common practice that has lasted in the region until today (Solanes Carraro & Vela RamĂrez, 2000).

The outside space of the houses became the focus of everyday activities and domestic

practices. It was the space where inhabitants probably spent most of the time; as it was used for food processing, cooking, eating, and for the manufacture of textiles, stone tools, baskets, and

Fig. 9

Construction section of a typical Olmec dwelling. Made by author with information from Solanes Carraro

& Vela RamĂrez (2000)

scale 1:50

pottery. For the lower social class, the burials of family members were also done adjacent to the houses, which speaks about the importance of rituals within the residential space, A common characteristic from most of the cultures in Mesoamerica (Joyce, 2011). The inhabitants created an intimate link with their piece of land, which a reflection of their cosmology and religious believes. The relation to death was a primordial aspect that affected the building traditions in that entire region, and it is one of the main influences that has transcended in their architecture until nowadays.

THE MIXTEC AND ZAPOTEC CULTURES

The influence of the Olmec culture can be found in every subsequent civilization that es-

tablished parallel or after them, not only in architecture but also in religious, scientific and social development. In the area surrounding Monte Alban, the capital of the Zapotec Culture, there were found remains of houses made of wood, bajareque, and palm, which had tools from the Gulf of Mexico. What makes anthropologists suppose an influence of the Olmec culture and its traditions

2. Background | The Influence of the Vernacular

in architecture and art (Campero, 2011). At the same time, the Zapotec Culture profoundly influenced the Mixtec Culture and the other way around, even though they were in constant conflict for territory. These two civilizations established and lived almost parallel in what today is the state of Oaxaca.

Probably the main alteration that these cultures introduced into the housing typology was

the use of adobe blocks for the construction of walls. This technique consists of mixing clay with straw or natural fibers and forming blocks with a wooden framework and leaving to get dry with the aid of the sun. This type of construction was found mainly in the central valleys of Oaxaca, which do not have a tropical climate. It also extended widely to other central areas of Mexico, where it influenced the building traditions of other cultures from that region. It used a similar type of wooden structure like the Olmec houses, but instead of covering the roof with palm leaves, it was covered with woven straw (Daneels, 2015). However, it can be inferred that this building technique was later taken and adapted in the coastal areas of Oaxaca, on sites like Guiengola and Tututepec, because nowadays it remains as one of the main techniques that are used in that tropical region.

Fig. 10

Construction section of a typical Zapotec dwelling. Made by author with information from Daneels (2015) scale 1:50

THE MAYAN CULTURE

The Mayan Culture is one of the most studied ancient civilizations by archaeologists and

scholars around the world and therefore there is more documented information about their architecture and building typologies. However, there are some sites like Palenque or Tikal that lay in the middle of the rainforest, where the enormous amount of trees and high vegetation, together with the high humidity, destroy and make difficult the location and conservation of archaeological remains (Alfonso, 1991). This contrasts with areas that have facilitated the findings in the central and north of the Yucatan Peninsula and even in Guatemala and Honduras, where there is evidence of single and multi-family structures.

The Mayans were very careful in the election of materials depending on the external con-

ditions. According to a study made by Viqueira & Freixanet (2006), the election of materials depended on the height where the constructions were built. The structure was built mainly with tropical wood, and the roofs were covered with palm leaves like in the past example. Though, the

2. Background | The Influence of the Vernacular

material on the walls changed. In the lower heights, they were made of wooden sticks or reed. In the medium heights they covered them with mud (bajareque), and in the high parts, they used complete wooden planks. They did not leave a significant proportion of openings to the outside, only 20 â&#x20AC;&#x201C; 30% ratio. The chosen materials protected the interior of sun exposure and increased the thermal mass of the envelope, depending on each case. When it was necessary the ventilation was allowed in between the structure and on top of the roof. As the interior, had almost no partitions, it enhanced crossed ventilation and in that way, generated a cooler micro-climate (Yuan, 2002). The pitched roof had, depending on the amount of rain, a bigger or smaller slope that went from 50 to 70%.

The smallest unit of the Mayan residential typology frequently had only one floor with

a rectangular and compact shape. It consisted of only one room, sometimes partitioned into two spaces: one for sleeping on mats rolled out on the floor and the other for any other activity when it could not be performed outside. There have also been findings in the North of Yucatan, close to Mayapan, where the houses presented an oval shape but were built with the same materials and

Fig. 11 (2016)

Construction section of a typical oval Mayan dwelling. Made by author with information from Carballo scale 1:50

techniques. These two typologies belonged probably to the lower class of the population. Like in the Olmec Culture there are findings of sets of constructions that belonged to different family members, which formed courtyards or patios. The house was mostly seen as a place of shelter and protection because many of their activities were performed outside (Abrams, 1994). Different from the Olmecs, the Mayans buried the death below the houses and included altars as part of the internal distribution, a tradition that later combined with the Spanish culture and was reflected in the architecture of the region until today.

Also on the north of Yucatan and close to Chichen Itza, there have been findings of an en-

tirely new typology that belonged to a higher class and was denominated Tandem. It was built over a stone platform and consisted of a one-floor structure with a U shape, which created a covered loggia that contained stone benches. The internal space was divided into several rooms, and in some cases, stone columns helped to separate the uses and the internal and external spaces (GarcĂa Targa, 1992). In some cases from the late periods, the walls were entirely built with masonry, and the roofs had probably only one slope, still built with wood and covered with palm leaves. The use of exterior covered spaces became a primordial element in the building traditions of the region,

2. Background | The Influence of the Vernacular

which was later on complemented by similar typologies that were later imported with the Spanish colonization.

THE AZTEC CULTURE

The Aztec Empire was the last important civilization to flourish in Mesoamerica, before

the arrival of the Spaniards. It is believed that they lived as a culture for around two centuries, but their organized structure and dominance over other cultures, allowed them to grow relatively fast and expand their territories. Even though they established mainly in Tenochtitlan, what today is Mexico City, they also extended their domain to different regions of the Gulf of Mexico and the Pacific Coast like Tehuantepec in the State of Oaxaca. Their architecture can be mainly found in the central areas of the country, but the influence that it brought to the building traditions, can be perceived until today. Some of the main elements that transcended were the floor plan distribution, the use of materials and the use of colors.

Fig. 12

Construction section of a typical Mayan Tandem dwelling. Made by author with information from GarcĂa

Targa (1992)

scale 1:50

The homes of the low and high classes were similar in layout and pattern but different in

size, decoration, and construction materials. The houses of the elite were made of tezontle (volcanic stone), and limestone with wooden slabs and the interior walls were painted with colorful murals. The homes of the lower class were modest. They lived in calpullis (Multi-family structures), and their houses were made of adobe bricks, wood, and straw. The finishes were done with clays or stuccos. They painted their walls using lime and natural pigments like blue indigo and red cochineal. They also used brown and ochre clays to paint the door and window frames and the plinths. The use of color was sometimes related to magical and hierarchical aspects (Prieto & Carrillo, 1978).

Excepting the palaces, the Aztec residential spaces had usually only one floor. One resi-

dential unit consisted of different rooms interconnected and sometimes they had an open central space, which could be shared with other units. In contrast with other cultures, they started to have clear differentiation in the uses of the spaces. Regularly they would use one room as a sleeping area, another room was the kitchen, and adjacently they had an eating space. There was usually

2. Background | The Influence of the Vernacular

a different room dedicated to shrines for their gods and offerings for their ancestors. A separate room contained the baths, and sometimes they even had a different space to exchange goods and products (Aguilar-moreno, 2007). This way of life, the household dynamics and the characteristics of the typologies also found similarities with the ones from the colonial period that started to shape the building traditions in the following centuries.

Fig. 13 (1978)

Construction section of a typical Aztec dwelling. Made by author with information from Prieto & Carrillo scale 1:50

2.2

SPANISH COLONIZATION

2. Background | The Influence of the Vernacular

Upon their arrival to Mesoamerica, the Spaniards found a divided territory that was ruled

by the Aztecs. Excluding the Aztec region, most parts of the territory had scattered populations without clear organization, with only the remnants of what once were more magnificent civilizations. The Spaniards took at first most of these people as allies, who saw them probably as deities. These internal conflicts, together with their military supremacy, made it relatively easy to get control over the Aztecs. However, the battles combined with other problems like epidemics (which were brought by the Spaniards) and drought, reduced the Mesoamerican population by up to 80%. So the first solution of the conquerors to the problem of dispersion consisted in grouping the indigenous people into new settlements that were called â&#x20AC;&#x153;Indian townsâ&#x20AC;?. This allowed the Spaniards to have better control over them and to quickly teach them the Christian doctrine (de la Torre Villar, 1995). The cities and towns were laid out according to a regular and strict plan that was implemented across the Spanish colonies and was stated in a document called the Laws of the Indies (R. C. Smith, 1995). These interventions can be considered the first great influence that would mark Mexican urbanism and architecture until today.

The planning of cities and towns involved first the precise location of the site according

to the physical conditions and the climate and close to existing pre-colonial settlements. The laws established the introduction of a rectangular grid, in the direction of the cardinal points, forming first the streets of the new settlement. In hot climates, the streets were narrower than in cold or template climates. The central space had to be dedicated to a public plaza, and a church was built beside. The other plots that surrounded the plaza were dedicated to the civil authority. The rest of the blocks, which were around 40 meters long in the case of the towns and 80 to 100 meters long in the case of the cities, were divided in 4 and distributed among the population. The ones closer to the center belonged to the most powerful families and the ones farther to the lower classes (Torres Urquijo & Fernández Christlieb, 2006). At the beginning of the colony the Spaniards and the “Indians” as they called the local people, did not mix.

Most of the Spanish immigrants lived in the centers of the big cities; some others lived in

rural houses called haciendas, and just a few soldiers lived in small fortress-towns called presidios. Most of the settlements were located in temperate climates, as ordered in the Laws of the Indies. Mexico City, Guadalajara, and Puebla were the most populated and where the elite lived. Nevertheless, there were also strategic locations that obliged them to establish in tropical and arid climates like the cases of Merida and Veracruz in the tropical south of the territory or like Zacatecas and Monterrey in the north. Most of the indigenous population lived in “Indian Towns” that worked as satellite settlements on the outside of the cities, and therefore most of them were also located in temperate climates. However, there were also many, as we can see in figure 18, that were scattered along the territory. This created a clear differentiation between the social classes and also the way of living, including housing typologies and the building traditions.

THE SPANISH CITIES

To be able to understand the building traditions that the Spaniards brought to New Spain,

as they called the territory where today Mexico is located, we have to understand as well their history and the cultures that influenced their architecture. By the time they arrived in America, Spain

Santa Fe

Monterrey

Durango Zacatecas S.L.Potosi

Guadalajara

Merida

Guanajuato Morelia

Mexico Puebla

Veracruz

Oaxaca

San Cristobal

Guatemala Planta abierta techo plano Planta abierta techo inclinado Planta cerrada techo plano Planta cerrada techo inclinado

Spanish cities and Haciendas Settlement Spanish city Hacienda with open floorplan and flat roof Hacienda with open floorplan and sloped roof Hacienda with closed floorplan and flat roof Hacienda with closed floorplan and sloped roof Climate Hot arid Hot tropical

Fig. 14

Map of Mexico with Spanish cities and haciendas. Made by author with information from Kusuhara (2010)

200 km

had just completely expelled the Arabs from the Iberian Peninsula and achieved their unification after the Middle Ages. The Arabs had been partially ruling that territory for around seven centuries, which was before occupied by the Romans, who were also there for approximately seven centuries as well. In between and before, other cultures inhabited it like the Visigoths and the Celts, but they did not have the influence and the extension of the other two cultures. This mixture of styles and building traditions were developed over time in climates and physical contexts that found similarities with the ones encountered in America, and therefore it was easier to adapt such building traditions to an entirely new territory.

The population from Spain that arrived in Mexico came at first mainly from AndalucĂa,

because all the ships departed from there and it was where the merchants that started to bring goods from the colony were established. AndalucĂa was the region with the most significant Arab influence in Spain, and therefore when the new immigrants started to settle in the center of the cities, they built with very similar typologies like the ones found in cities like Seville or Cordoba. Together with their new floorplan distribution they also brought new building techniques into the residential typologies that were never used before by the locals like the use of roofing tiles, burned brick, iron, and carved wood. There were also other that turned to be similar between both cultures like the use of stone, adobe, and plastering (Prieto & Carrillo, 1978).

The most common typology used among the Spaniards was the patio or courtyard house.

This typology has its roots in arid climates, like the ones found in large part of the Arab region in the North of Africa. The courtyard helps to create a microclimate, serving as a passive cooling strategy in the constructions, thus ideal for hot climates. Even though these Spanish constructions were somehow imported, they had to adapt them to the specific physical conditions from each site and sometimes even to the skills of the labor, which was in most of the cases the indigenous people. So, the availability of materials, the building techniques, and the climate started to have a significant influence over the new constructions that created a differentiation among the typologies in the different cities. Most of them belonged to one family, and sometimes the servants also lived there. Less common were the collective courtyard houses called vecindades, which were generally used as lodges and were owned by the church (Rebolledo, 1998). Nevertheless, this typology was an

essential influence for future multi-family structures that were developed in Mexican cities after the colonial period.

The typical courtyard house consisted of a one or two-floor construction that filled the

whole footprint of the building plot leaving a patio in the center or in the shape of a “U” or “L”, where the rest of the sides were surrounded with perimeter walls forming then the patio. The ground floor sometimes contained commercial spaces to the street. The entrance to the house was always through a vestibule called zaguán. The vestibule was connected to the adjacent rooms or to a semi-open hallway that surrounded the courtyard called portico, which distributed the rest of the spaces of the house (Pacheco León, 2000). The rooms frequently had relatively high ceilings from around 4 to 6 meters, depending on the climate. In the case of the houses with two floors, the sleeping rooms were located in the second and were also distributed through a portico. In the rooms that were facing the street, they incorporated balconies sticking out of the facade, a new element, also taken from the Arab architecture. They also introduced iron for the handrails and frames around the windows, ornaments that became later on primordial to the building traditions in Mexico.

2. Background | The Influence of the Vernacular

Depending on the location there were some variations of the typology. The walls and the

colonnades were most of the time built with masonry and adapted to the stones from each place. The limestone was preferred because of its malleability, but in the central regions of Mexico, they also used volcanic stones like tezontle and cantera. The walls were regularly built with one layer of big irregular stones joined with clay mortar and in some cases with a compound wall with two layers of smaller stones by side and a central layer of rubble and clay mortar. In the case where stones were not available, or it was too expensive to build with, it was replaced with adobe blocks. This was very common in the north of Mexico, where big blocks called sillar were also used to increase the thermal mass of the constructions. In some cases, but less commonly, they were built with burned bricks. Sometimes and also depending on location, the walls were plastered with clay and lime to reduce erosion. The percentage of openings also varied. In arid climates, it was relatively small to the outside around 20 to 30%, and it increased on the façades of the courtyard, where a fountain was typically placed in the middle to raise humidity (Carrazco & Morrillon, 2004). In tropical climates, the percentage increased to the outside and towards the courtyard to enhance

Fig. 15

Construction section of a typical Spanish elite dwelling. Made by author with information from Pacheco

Leรณn (2000)

scale 1:50

natural ventilation.

Typically the ceilings and roofs were built with wood as the main structure. The ceilings

were done with a layer of beams or trunks supported over the walls, then a layer of cut wood on the other direction, on top a layer of poured clay mortar and then a layer of burned clay flat tiles. The flat roofs, which were more common in arid and temperate climates, were built with a similar technique, but on top of the wooden beams they added secondary beams, then a layer of tiles and on top a layer of mixed clay and straw as insulation. The thickness changed depending on the climate, and they stamped it to achieve the necessary inclination to channel the water. They used a mix of burned barley and pine wood ashes as a waterproof layer. On locations with much rain, sloped roofs were preferred. In such cases, they used a similar technique, but they formed triangles with the wooden beams then added the same layers as explained before and on top a layer of roof tiles. The type of wood that they used the most was cedar, oak and other types of pine (Moya Olmedo, 2013), but they also adapted to what was available in the region.

2. Background | The Influence of the Vernacular

Throughout the colonial period, the Spanish cities in Mexico started to incorporate traits

from the different architectonic styles from Europe. This could be seen especially religious or government buildings, but also in some residential buildings from the elite. The main architectonic elements that reflected this transformation were the colonnades, the arches and the ornaments from the faรงades. In the beginning, the proportions and the physical characteristics of these elements were based on Renaissance principles following the classical architectonic orders. Then, on the 18th century the showy ornaments with floral and vegetal patterns, typical from the baroque style, started to appear more often, evidencing, even more, the difference of social strata in relation with architecture (Pacheco Leรณn, 2000).

THE HACIENDAS

The Spanish cities were the places where the commercial activities and exchange of prod-

ucts took place, but the extraction and production of goods happened in the rural areas. There, a new typology originated and was called hacienda. These were large pieces of land with plantations,

Fig. 16

Construction section of a typical hacienda dwelling from arid climates. Made by author with information

from King (n.d.)

scale 1:50

mines, factories or the combination of any of them and they also had a residence or villa of the Spanish elite who owned them, which were called casa grande, but are commonly known also as hacienda. Slavery was prohibited, but the people working in these areas belonged to the lowest socio-economic sector of the population.

According to a study conducted by I. Kusuhara (2010), these types of buildings were rep-

licated in different parts of the country, with modification mainly on the shape depending on the climate. They had a similar configuration and building techniques as the constructions from the cities, but with the main difference that they were regularly bigger and wholly detached. The typical arrangement of the floor plan in arid climates was closed with a courtyard in the middle; they also had regularly flat roofs. The common arrangement in tropical climates was open in the shape of “I” “L” or “U”, with sloped roofs. In both cases loggias were placed on one or both sides of the construction, de-pending on the orientation to avoid direct solar irradiation in the rooms. The opening also followed the same patterns as before: in tropical climates, it was common that the rooms had openings to both sides to allow crossed ventilation, while in arid climates the percentage of openings was smaller.

2. Background | The Influence of the Vernacular

The building materials were also used depending on availability. The use of stone was

common in the south and central areas of the country, while the clay was used more on the north. A new building technique also appeared within these constructions. In some cases rammed earth walls were built, as a division between rooms or as perimeter walls to delimit the plot. This technique consists of a mix of clay, lime, sand, and water, which is poured inside a wooden framework and then stamped in layers of 20 to 30 cm. This technique was observed in places where water was not available in large quantities and probably is why it was preferred over Adobe (Casa de la Ciudad, 2018). Another technique that was used before by the Spaniards mainly in religious and government buildings, which is the use of stone or brick vaults for the roof, can also be found in isolated cases of this type of residence.

Fig. 17

Construction section of a typical hacienda dwelling from tropical climates. Made by author with informa-

tion from Kusuhara (2010)

scale 1:50

Indian Towns Settlement Indian town Climate Hot arid Hot tropical

Fig. 18

Map of Mexico with the indian towns around 1800 AC. Made by author with information from El Colegio

Mexiquense (2019)

200 km

THE INDIAN TOWNS

It was not always possible for the Spaniards to relocate the Indians from their original set-

tlements, many times they encountered resistance among the people, but when it was possible the towns followed the same urban patterns from the Spanish cities with a church and a plaza as the central elements, a and grid of streets as the organizational principle. In those cases the people had to rebuild their houses, so they did exactly as they knew, keeping the same building traditions and typologies depending on the region and on the availability of the materials on site. They also kept their social and political structure (Torres Urquijo & Fernández Christlieb, 2006), so initially, the result regarding the building traditions, was a repetition of what they had before but following the new grid that was imposed. This generated transformations mainly on the urban level in the dynamics to the street, and the transitions from public, semi-public, semi-private and private, but the building techniques, the materials, and floor plan distribution remained the same.

With time the people in these towns started to incorporate behavioral aspects from the

Spanish culture. Catholic rituals started to replace the Indian’s past customs. The European way of life became an aspiration. Different casts started to mix, and cultures started to merge. All of this was reflected later on in their building traditions. Mestizos was the name given to the children of the Spaniard with the Indians, a mixture of two cultures that generated a “new” race. The same happened with the vernacular architecture of the territory. The three hundred years of colonization resulted in an architecture that took characteristics from the pre-colonial and the Spanish building traditions. It also resulted in a very uneven socio-economic distribution of the population. By the beginning of the 19th century, the population distribution was composed of 59% Indians 22% mestizos and 18% Spaniards. From that 18% that represented most of the elite, just a few started to accumulate the concentration of economic resources and land. The rest of the “marginal elite” allied with the mestizos and Indian population and started the civil war that resulted in the independence of Mexico from Spain (Jauregui, 2010).

2.3

19th AND 20th CENTURIES

2. Background | The Influence of the Vernacular

Little changed concerning socio-economic organization in the following decades after the

independence, in the first half of the 19th century. The power and resources stayed in the hands of just a few, most of them were part or related to the Catholic Church, which continued to be the most important institution in the country. The haciendas system continued to dominate the rural areas of the territory, increasing even the inequality between social classes. The political instability generated even more division that was taken advantage of by The United States that took a significant part of the territory in the Texas War of Independence (1836) and the Mexican-American War (1846-1848). All of this together with several epidemics caused a decrease in population and delayed economic growth in most of the country (Burian, 2015). However, the states that made up the north of Mexico to the new border saw an opportunity on the economic growth of the United States and started to develop differently than the rest of the country. This proximity would also influence their culture and building traditions creating a clear differentiation from other regions in Mexico until today.

The second half of the 19th century was marked by the division between government and

church, by some years of French occupation and by the beginning of industrialization and open markets. When the liberal party came to power, they established a series of reforms that sought to bring progress by taking the authority and properties from the church, by the exploitation of agricultural land, by bringing education to all the population and by putting an end to traditions. However, they could not implement them as wished and encountered opposition from many groups. This division resulted in the invasion by the French, who took control of the territory between 1862 and 1867. This occupation generated some changes in the urban morphology of Mexico City and influenced some of the residential typologies from that region. However, the south and north of Mexico, that in that point remained challenging to access also continued with their transformations. After the French occupation and some years of political instability, Porfirio Diaz, came to power and stayed there for more than 30 years.

At the end of the century, the economy finally stabilized. The global economy accelerated,

and Mexico established itself as an important exporter of raw material, mainly to France and the United States that started to be seen as role models to follow. This, on the one hand, brought economic growth to the country and the elite, but on the other hand, it also produced an increasing demand for labor. The indigenous and mestizo workers in the haciendas and industries were heavily exploited (Arnold & Frost, 2009). Some of their leaders, then, started to claim for better labor conditions and the property of the land. They, together with other political groups that wanted to give an end to the dictatorship gave rise to several coups and internal conflicts that are known as the Mexican Revolution. These civil movements that reflected a highly corrupted political system developed parallel to an exponential increase of industrialization and population that were characteristic of the 20th century.

The exponential increase of population, which happened mainly in urban settlements and

on the second half of the 20th century, also generated a directly proportional increase of housing constructions as it can be seen in Figures 19 and 20. An urban settlement as defined by INEGI (1994) corresponds to a population of more than 2,500 inhabitants. Given the exponential growth of housing constructions, from this point on it is not possible to generalize on the housing typologies and passive design strategies that prevailed over the country, but it is, to point out the building

Urban and rural population growth 90 mi.

80 mi.

70 mi.

Population

60 mi.

50 mi.

40 mi.

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20 mi.

1980

1990

2000

2010

1980

1990

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10 mi.

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Urban population Rural population

Inhabited housing constructions growth 30 mi.

25 mi.

Number of inhabited housing constructions

20 mi.

15 mi.

10 mi.

inhabited housing constructions

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5 mi.

1900

2. Background | The Influence of the Vernacular

Year

Fig. 19

Urban and rural population growth in Mexico. Made by author with information from INEGI (1994)

Fig. 20

Inhabited housing constructions growth in Mexico. Made by author with information from INEGI (1994)

techniques that resulted from the use of industrialized building materials, which almost substituted the use of natural-low-carbon materials. It is also possible to explain the public and private policies that led to uncontrolled growth of the urban sprawl in cities favoring the development of single-family houses in the form of social housing, suburbs, gated communities, and slums. The transformation of the building traditions also affected the towns and rural areas, where the local knowledge and vernacular building solutions started to get lost, mainly because they were seen as something negative, as the representation of a society that has not progressed. All of these started to give space to generic constructions that did not respond anymore to the local context and the climate.

THE GROWTH OF URBAN SETTLEMENTS

Depending on the size and population growth, most of the Latin American towns and

cities that were founded during the colony with the Spanish urban grid have fol-lowed specific patterns for their expansion. At the beginning of the 20th century, most of the towns and cities in Mexico were still relatively small and followed a concentric ring system that prevailed during the past two centuries, where the elite occupied the residential spaces closer to the center, and the social classes and favorable conditions de-creased towards the exterior. In many small towns, this system prevailed during most of the century. In the small settlements where the grid was not imposed the towns grew more organically, however, the pattern where the high classes occupied the most desirable and larger pieces of land remained the same. In some specific cases of big cities like in Monterrey, Guadalajara and Mexico City, industrialization and commercial areas and urban axis started to appear changing the morphology and therefore the system or pattern of growth. However, in general, this urban and industrial expansion was delayed because of the Mexican Revolution.

The Mexican Revolution was articulated based on a complex cultural discourse that pro-

moted the recovery of the past and indigenous identity and traditions. It also encouraged a transformation of the socio-economic system where the conditions and life quality of the lower social classes would be improved. Nevertheless, the new government based their ideology on a neoliberal conception of progress, where industrialization and consumption were seen as a solution. They de-

veloped a massive program of construction that included infrastructure, hospitals, schools and of course housing in which, with rare exceptions, traditional building materials and systems seemed to have disappeared (Vizcarra de los Reyes, 2017). This generated in some way an opposite effect from the original discourse because the gap between socio-economic classes grew even further. Quality of life was disguised with an ideology similar to The American Dream, in which living in or close to the productive cities, owning a car and a house would lead to a better life, which in most of the cases did not happen.

Since the 1920s and until the 1950s the model of expansion in fast-growing Latin Ameri-

can cities got more complex, as explained first by Griffin and Ford (1980) and complemented later also by Ford (1996). The Spanish center became an active Central Business District (BCD) with commercial, gathering and governmental spaces. This activity was extended through the axis that connected the center with another commercial area and all of them surrounded by the elite residential zone. On a second ring, there was a zone with less density and with a residential area from high and medium class. The third ring was the area with the fastest growth, where the public programs of infrastructure and housing for the working class started to appear. However, a large

2. Background | The Influence of the Vernacular

part of the workers was unable to afford the rents in any of these rings, so a fourth ring, where the big industries were located, started to become inhabited with informal settlements or slums. In many cases, they were even controlled by the federal government, which in order to avoid strikes and social movements, started to give away land on the outside of the city. Then the new residents received as a â&#x20AC;&#x153;giftâ&#x20AC;? electricity, access to water and infrastructure in exchange for electoral support. They also received bags of cement, concrete blocks and corrugated steel sheets to build their homes (Beezley, 2011). This practice continued through decades, and the provision of building materials by governments is usual until today. This short-term thinking and political oriented development have shaped since then in a significant way the materiality and image of cities, towns, and slums.

The second half of the 20th century was characterized by an exponential growth of the

urban population, which increased ten times its size. From that point on many of the cities started to grow with a polycentric system. Different economic and commercial centers started to scatter guided by public policies and private investment. This generated suburbanization of the elite and high classes that moved from the BCD to single-family houses in the periphery, and in many cases

into gated communities. Other neighbourhoods from lower socio-economic classes followed the same pattern, increasing, even more, the urban sprawl, until reaching other towns and municipalities, incorporating them into a Metropolitan Area (Sousa Gonzáles, 2008). In many cases, marginalized groups occupied the original CBD’s, which became the historic centers, renting a space in the old vecindades or in the uninhibited Spanish residences that were subdivided. The process varied depending on the city, but in most cases, it was characterized by a fragmented grow in which social inequality divided the cities into segregated islands (Buzai, 2016).

The intervention of the government in the housing sector had a significant influence over

this type of growth. The intervention ranged from direct housing construction by federal public agencies and the various financial mechanisms used to give credits to particulars and the private sector, up to the set of policies related to the possession, valorization, and use of the land and administration of national reserves. In the 1960s, housing policy received a substantial boost with the housing financing program. Its initial purpose was to facilitate the purchase of social housing and significantly increase its construction to generate jobs and thus generate growth effects in other industrial branches. With this program, bank loans for public and private organizations were exponentiated. However, the loans for the acquisition of housing only benefited people with sufficient income to guarantee the payment of the loan. Therefore, it was not consistent with the initial idea of benefiting large population sectors. This caused the segment with the lowest economic resources to informally try to meet their housing needs, near the cities with the increasing construction of slums and in rural areas with the construction of “lost villages” far from infrastructure and basic needs (INEGI, 1994). In 1972 the National Workers’ Housing Fund Institute was founded, a public institution that since then has become the largest source of mortgages and loans in the country with over 10 million housing loans, until 2018 (INFONAVIT, 2018a).

On the two last decades of the 20th century the urban population in the country doubled,

but on the other hand, the urban sprawl grew seven times (SEDESOL, 2012). That is primarily due to the financing policies that began in the 1960s and continued until the beginning of the 21st century. During these decades, the number of homes exceeded population growth, being most of them single-family houses, which led to a decrease in the number of inhabitants per household. By the end of the 20th century, the country’s population almost reached 100 million. There were 55

Tijuana Cd. Juarez

Hermosillo

Chihuahua

Reynosa

Torreon

Monterrey

Saltillo

S.L.Potosi

Tampico Cancun

Leon Merida

Queretaro Guadalajara Toluca Mexico

Veracruz

Cuernavaca Puebla

Acapulco

Villahermosa Oaxaca

Merida

Metropolitan Areas Inhabitants + 1,000,000 500,000 - 1,000,000 200,000 - 500,000 100,000 - 200,000 Climate Hot arid Hot tropical

Fig. 21

Map of Mexico with metropolitan areas with more than 100,000 inhabitants. Made by author with informa-

tion from INEGI (2000)

200 km

Metropolitan areas with more than 100,000 people (INEGI, 2000), where almost 40% of the population of the country was concentrated. All of them followed similar patterns to the ones explained before. 15 of these cities were developed within arid climates, and the other 15 grew within tropical climates. If we also add the towns and small cities that were developed in these climates, it means that a large percentage of the housing constructions in the country were built in areas where physical and climate conditions were not ideal for human settlements, so an architectural response of adaptation to these local conditions could be expected. The search of industrialized solutions that could be replicated massively to meet the fast and disorganized growth generated a building tradition where the use of reinforced concrete, bricks, and concrete blocks became a generalized answer that was replicated throughout the country, regardless climate, culture or socio-economic position.

THE CEMENT ERA

With the arrival of modernization, the idea of progress was reflected in architecture,

through the replacement of natural materials, which were employed throughout human history, by those produced as a result of the Industrial Revolution. There was one specific material that transformed the building tradition and the country’s landscape: cement. Even though this material was invented in 1845 in England as Portland cement, it was introduced in Mexico by the end of the 19th century. The production of this material was only possible after industrialization because its process involves the burning of fossil fuels in a rotary kiln (Vidaud, 2013). Its main component, called clinker, is obtained by mixing limestone and clay and heating them at very high temperatures (1400 – 1600 ˚C), which makes it a great source of pollution and energy consumption. However, it earned acceptance in the Mexican market very fast. When cement is combined with other aggregates and water, it creates concrete, mortar, and plaster, which have been used in many forms in the housing sector.

On the first decade of the 20th century, concrete was mainly used for the production of

moldings that served as imitations of carved stones and tiles as ornamental parts of the façade. So

in the housing sector, it was first targeted to the high socio-economic class. The use of reinforced concrete, with steel rods, was at the beginning implemented in big infrastructure projects, which allowed the growth of the internal cement industry. Cemex opened the first plant in 1906, a company that would become the largest cement producer in Mexico and the fifth worldwide, and another two companies followed in the subsequent years. It was then that concrete started to be used as blocks for the construction of walls for the elite residences and soon the material gained a reputation as a symbol of high social status (Fry, 2008). The production was then partially interrupted because of the Mexican Revolution, but it was revived by the early 1920s.

Since then, the fast growth of the cement industry can be attributed to many factors,

like the availability of raw materials and cheap oil in the country, or the diffusion of concrete by recognized architects from that time, but probably one of the main reasons, was the marketing strategies used by the industry and construction stakeholders. As described by Walker (2000) and by Fry (2008), the propaganda that was distributed during the first decades of use was focused on the health benefits of the material, its malleability and ornamental features, its low price, and most importantly on its physical properties, like durability and structural resistance. This factor became

2. Background | The Influence of the Vernacular

primordial towards its acceptability, also demonstrated by a study that will be explained in the next section. This way of promotion arguably targeted mainly the low and mid-socio-economic classes, because they were the ones that until that point built with perishable and high-maintenance materials like clay, wood, reed and palm leaves. One example can be found in one of the articles of the journal “Cement: Towards a refinement of construction” distributed between 1925 and 1932. The article stated:

“The concrete post has an advantage over other types, which is that of a depreciation factor which is practically null; that is to say, it acquires greater consistency with time, and can thus be considered to have an indefinite life” (Cemento Portland, 1928, as cited in Walker, 2000, p. 93)

The same Journal published another article that also stated its benefits concerning durability and earthquakes, which were very common in the Pacific coast and central regions of Mexico, including Mexico City:

“In the landscape of Santa Cruz, in the Colonia del Valle,… there is a cheerful bungalow, which despite its small proportions, was built by its owners to resist the calamities which we refer to as time, rain, earth tremors, humidity, rats, etc. etc. It is built of concrete blocks” (Cemento Portland, 1925, as cited in Walker, 2000, p. 93)

This second article, when referring to a bungalow built by its owner, points out a situation

that became very common in the housing sector in Mexico: self-construction. This market, which belongs to the low socio-economic classes, became probably the most important for the cement industry in the country. It has been noted that even with economic crisis it is a market that remains stable (Salomón, 2006). It is also the market where most of the construction workers belong to, given the low salaries that this sector receives. Therefore, the creation of a building tradition, which is mostly based on products where cement is used, would be reflected in the majority of constructions in the country. This influence was also possible through self-construction manuals that were highly distributed by the main cement private companies, sometimes even with the aid of the public sector. These manuals explained step by step the construction of a house with the use of cement in the form of reinforced concrete for the foundations, floor, columns, slabs, and roof; with concrete blocks and mortar for the construction of walls and with the use of plaster as a finishing. This type of construction became the base for most of the housing typologies in the country. Depending on the socio-economic class the size, the finishing and sometimes the material to build the walls changed, but the building technique and the process of construction, which is explained in figure 22, remained the same.

The use of cement boosted then together with the urban sprawl expansion from the sec-

ond half of the 20th century, which was explained before. Its characterizing grey color started to fill the mountains and hills, which were covered with slums. Prefabricated reinforced concrete pieces assembled with prefabricated gypsum panels supported the ideology of mass production that occupied other sections of the landscape with repeated typologies of social housing. It also accompanied the suburbanization into the gated communities of the elite, who disguised the concrete structures and block walls with veneers, moldings and colorful plasters that mimicked pre-Hispanic, colonial or other imported traditions. Together with steel and glass it also became the symbol of strength and progress in low and high-rise buildings in the city. With time the same building

2. Background | The Influence of the Vernacular

Fig. 22

Steps to self-build a dwelling. Made by author with information from CEMEX (2017)

Predominant materials in walls (1930-2010) 25,000

Number of inhabited housing constructions

20,000

15,000

10,000

2010

2000

1990

1980

1970

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Year

Concrete block or brick Adobe Wood Bajareque Carrizo or Bambo

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Reinforced concrete Asbestos or metal sheet Burned clay tiles Wood and palm leaves

2010

2000

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Number of inhabited housing constructions

2. Background | The Influence of the Vernacular

Year

Fig. 23

Predominant materials in walls in Mexico (1930-2010). Made by author with information from INEGI (2010)

Fig. 24

Predominant materials in roofs in Mexico (1970-2010). Made by author with information from INEGI (2010)

technique was also brought into towns and the rural areas that started to receive all the influence of the cities. In short words, it became the base of a generic building tradition that was and still is repeated throughout the whole country.

It can be argued that the use of cement in its different forms has become a vernacular

tradition because the extraction of raw material and many times the production are done locally. Nevertheless, by the definition of vernacular that is used for this study, the application of this building technique has lacked the adaptation to the local conditions, mainly in regions with arid and tropical climates. This is mainly because of the thermal properties of the material, and because the majority of times the typologies that surged with its application are not suited to those climates. This will be further explained in detail with the different case studies in the following chapters. Moreover, the production of the material, which in the case of Mexico involves the burn of fuel oils, petroleum coke, coal, tires and other industrial waste (Jacott, Reed, Taylor, & Winfield, 2003), contributes in a great extent to the carbon footprint that affects, among other things, climate change.

THE REVIVAL OF VERNACULAR BUILDING TRADITIONS

The previously mentioned problems that arose after industrialization and grew after the

second half of the 20th century, with the extreme use of energy and resources and the loss of vernacular traditions, have been noted by people around the world that have attempted to solve them or minimize them. In relation to architecture and construction, there have been several efforts that have aimed to bring back vernacular traditions. First in search of local identity in the 1940s with the architectural regionalism that originated as a response to the international style of the modern movement, and second as part of the environmental movements that started in the 1960s around the world. In Mexico, during the 20th century, there were several important references from these movements; however, their influence stayed within a relatively small proportion of the population, mainly within the high social classes and the architecture and academic community.

The search of regionalism in Mexican architecture is related to the work that originated

with Luis Barragan, who sought to bring a regional identity in architecture in the country. Then different architects like his disciple Ricardo Legorreta, or Teodoro Gonzalez de Leon, Pedro Ramirez Vazquez, Antonio Atollini, and several others, also spread it. Even though their work serves as an essential reference of the vernacular influence, it remained as described by Curtis (1986) a mix of two ideals that opposed: traditional and modern, which resulted in modern regionalism or regionalist modernism. On the one hand it evoked pre-Hispanic and colonial architecture with the use of colors, patios, and in some cases local materials, and on the other hand, it kept the search of simple and somehow monumental forms of modernism. It created then a new building tradition which belonged mainly to the elite, but which started to be replicated by other architects along the country and became a common topic in architecture universities. It then arguably lost in most of the cases its values as regional, because this tradition became a style that was implemented in houses regardless of the natural or social context of the place.

In the 1960s regionalism took part of the environmental movements that sought to achieve

low energy and low carbon constructions based on the adaptation to a specific climate. The term bioclimatic architecture was for example used by Olgyay (1963), to define a type of design that

2. Background | The Influence of the Vernacular

was based on following passive strategies to achieve comfort depending on the climate. In Mexico these ideals arrived within the next decades; however, they were only followed and were focused on a tiny part of the population and mainly studied in the academic community. In was not until 1979, when Valeria Prieto published “Vivienda Campesina en Mexico” and in 1981 “Manual para la Construccion de la Vivienda Rural”, that specific attention was given to the vernacular building traditions from specific communities, concerning their culture and climate. In 1984 INFONAVIT published “Regionalización de materiales y especificaciones de la vivienda” with similar intentions in relation to the applied building materials in social housing.

The publications came as a response to the self-construction manuals that were distribut-

ed by the cement industry and other public and private organisms and promoted a homogenized or generic architecture. These publications served as a base for further studies on the topic and as a mean to document vernacular building tradition for their preservation; nevertheless, they did not gain the recognition or diffusion of the other manuals. As it was explained before, the tendency

to build with cement or other industrialized materials and building traditions continued to prevail throughout the 20th century. It was not only until the 21st century that movements related to sustainability, including the search of vernacular traditions, started to gain a social character and began to be implemented with repercussions in public and private sectors (Moreno, Cerutti, GutiĂŠrrez, & Olea, 2014).

2.4

21ST CENTURY

2. Background | The Influence of the Vernacular

The new millennium started with a similar situation than the past two decades, where

economic and population growth thrived the fast and unplanned decisions in the building sector. Even though there was a change of party in the federal government after 70 years of rule of the Institutional Revolutionary Party (PRI), what was described by Mario Vargas Llosa as the â&#x20AC;&#x153;perfect dictatorshipâ&#x20AC;? (El Pais, 1990), the new government followed up with the neoliberal strategies from the past century. They set as one of their main goals the intensification of mass social housing by financing 750,000 new houses per year within the first sexenio (six-year presidential term), and this number increased with the next presidential term. These financial supports were targeting the population that earned more than three minimum wages (MW), so around 30 to 40% of the population that were below this line had to buy or rent by self-financing (Hastings, 2011). Consequently, if we add the dwellings that were built by the other sectors of the population, we come to an increase of 69% of dwellings in the first 15 years of the century, from 21.5 to 31.95 million dwellings to meet the needs of around 126 million people (INEGI, 2015). Also during these years, there were no regulations that encouraged the developers to build sustainably, so this led to further expansion of urban horizontal carpets, talking little or no care about urban and architectonic qualities.

Despite the arguably adverse scenario that the housing sector has had during the past dec-

ades regarding building traditions, there have been lately efforts by several stakeholders to achieve a more sustainable future. On the one hand, public and private sector introduced new technologies and policies to improve energy consumption in the construction sector and on the other hand some brought back vernacular building traditions and passive design strategies. The cement industry, for example, has become more efficient by investing in research programs and their production processes, reducing their electricity and fuels consumption considerably (Jacott et al., 2003). The governments and other public institutions have incorporated a series of regulations and policies in their building codes that encourage the use of natural building materials and eco-technologies. They have also partnered with the academic and private sector to look for solutions that improve the efficiency of settlements and the life quality of their inhabitants (Herbert, Belsky, & DuBroff, 2012; Ziccardi, 2015). Moreover, there have been several architects that have promoted the use of vernacular traditions in different regions in Mexico, giving solutions for the different socio-economic sectors of the population given the relatively large gap that exists between low and high classes, and that is clearly reflected in the housing sector and the quality of life of the inhabitants.

THE SOCIO-ECONOMIC DISTRIBUTION

There has been a relatively large gap between socio-economic classes since the coloniza-

tion that started as a cultural dominance and has prevailed impacting every aspect of the society, not only in Mexico but it has become a pattern in Latin America. According to Stanford professor Terry Karl (2002), â&#x20AC;&#x153;Latin America is the most unequal region in the worldâ&#x20AC;?, which has led to an unjust society. Its countriesâ&#x20AC;&#x2122; economy and public policies work through the influence of the private sector, which always favors the elite group. Therefore any try to reduce the gap between classes has been affected by a corrupted cycle that neither right nor left political ideologies have been able to overcome. This is most clearly reflected in the wages, which at the same time are reflected in other sectors. When speaking about the housing sector, this inequality is exemplified in cities where informal settlements develop side by side with gated communities from the elite, or even in the rural areas where the haciendas system remains similar until nowadays. It is at the same time reflected in the building traditions that show different patterns depending on the socio-economic group.

The minimum wage (MW) in Mexico, as of January 2017, was 80 Mexican Pesos (MXN) per

day. According to a national survey that measures the incomes and outcomes of the households in Mexico (INEGI, 2016a), more than half of the total wealth of the population is concentrated within one fifth of the households that are on top of the socio-economic class, which are the ones earning in average more than 10 MW. The other 48.8% of the wealth is distributed among the other four-fifths of the population. One-fifth of the households that represent the lower socio-economic classes earn in average less than 2 MW. This survey takes into consideration the income received from jobs, remesas (international transfers), property rent and any other ordinary income. It divides the results into ten equal groups, called deciles, which makes it impossible to determine the wealth of the very top and bottom of the samples. However, some estimations calculate that the wealthiest 1% earn around 22% of the total income (Esquivel Hernandez, 2015). The distribution of the average income per household in Mexico can be observed in the following table: less than 2 MW. This survey takes into consideration the income received from jobs,

remesas (international transfers), property rent and any other ordinary income. It divides the results into ten equal groups, called deciles, which makes it impossible to determine the wealth of the very top and bottom of the samples. However, some estimations calculate that the wealthiest 1% earn around 22% of the total income (Esquivel Hernandez, 2015). The distribution of the average income per household in Mexico can be observed

2. Background | The Influence of the Vernacular

in the following table: Decile

Income per month

Income per day

Equivalent in MW

% of Income

$2,722

$91

1.13

1.8%

$4,735

$158

1.97

3.1%

III

$6,306

$210

2.63

4.1%

$7,852

$262

3.27

5.1%

$9,604

$320

4.00

6.2%

$11,612

$387

4.84

7.5%

VII

$14,144

$471

5.89

9.1%

VIII

$17,794

$593

7.41

11.5%

$24,014

$800

10.01

15.5%

$56,285

$1,876

23.45

36.3%

Table X Distribution of the working population by income If we take into consideration that the average housing rent in Mexico was around $2000 MXN per month in 2015 (Ziccardi, 2015) and the average household had 3.9 persons, we can understand the difficult living circumstances of a significant proportion of the population and the high rate of self-construction. From the total amount of dwellings that were built that year, the residents built 65% by themselves. From that number, around 50% is self-construction, and the other 50% is done with external aid. Private developers built the other 35% of the total but most of them financed by public instituTable 1 Distribution of the working population by income. Made by author with information from INEGI (2016) tions (Softec S.C., 2016). This reflects the great social division that exists in the country, but it also shows that the decision-making process in the construction sector in the country falls on a more significant proportion in the residents of the houses. According to INEGI (2015), detached single-family houses accounted for 92.2% of the total housing constructions, followed by apartment units with 5.2% and units in a

If we take into consideration that the average housing rent in Mexico was around $2000

MXN per month in 2015 (Ziccardi, 2015) and the average household had 3.9 persons, we can understand the difficult living circumstances of a significant proportion of the population and the high rate of self-construction. From the total amount of dwellings that were built that year, the residents built 65% by themselves. From that number, around 50% is self-construction, and the other 50% is done with external aid. Private developers built the other 35% of the total but most of them financed by public institutions (Softec S.C., 2016). This reflects the great social division that exists in the country, but it also shows that the decision-making process in the construction sector in the country falls on a more significant proportion in the residents of the houses.

According to INEGI (2015), detached single-family houses accounted for 92.2% of the total

housing constructions, followed by apartment units with 5.2% and units in a vecindad with 2%. The census does not show a specific distribution of the type of dwellings by economic segmentation; however, it can be inferred that it is directly related to the income per household. In Mexico, the size of the dwelling can also be a sign of economic status. The results of a national survey carried out by UNAM (Ziccardi, 2015) show the dwellingsâ&#x20AC;&#x2122; area per household as follow: 17.6% less than 40m2, 19.9% between 41- 60m2, 13.6% between 61-75m2, 12.4% between 76-90m2, 12.4% between 91-120m2, and 8.3% more than 120m2. There is also a homologated classification of housing market segmentation in Mexico, which resulted from an agreement between private and public stakeholders (Softec S.C., 2016). There are six housing categories that correspond to the price and therefore to the annual income of the households (Table 1). This classification can give an approximate estimation of the typologies per socio-economic group and will be used in this study to define the case studies in the following chapters. Table 2 gives an overview of the main characteristics of each housing typology.

The socio-economic differentiation can also be measured by the degree of marginaliza-

tion. This measure differentiates the areas of the territory according to the overall impact of the deficiencies that the population seems to have, as a result of the lack of access to education, residence in inadequate housing, the perception of insufficient monetary income and those related to living in small settlements (Bustos, 2011). It divides the population into five strata: very high, high, medium, low and very low degree of marginalization. Concerning dwellings, it takes into

can give an approximate estimation of the typologies per socio-economic group and will be used in this study to define the case studies in the following chapters. The following table gives an overview of the main characteristics of each housing typology: Type

Area

Economic

< 30 m²

Popular

30 - 50 m²

Traditional

50 - 75 m²

Middle

65 - 130 m²

Residential

65 - 150 m²

Residential-plus

100 - 350 m²

Characteristics 1-2 Rooms. not tiled. Mostly self-built detached or in slums. Single family Kitchen, living-dining area, 1-2 rooms,1 bath, 1 parking, tited, all services. Mostly mass social housing or self-built single family / apartment. Kitchen, living-dining area, 2-3 rooms,1 bath, 1 parking, tiled, all services. Mostly mass social housing, self-built detached or close to CBDs single family / apartment. Kitchen, living room, dining room, 2-4 rooms,1-2 baths, 1-2 parking, tiled, all services. Mostly self-built detached, close to CBDs or in gated communities single family / apartment. Kitchen, family, living room, dining room, 34 rooms,3-4 baths, 2-4 parking, tiled, all services. Mostly detached in suburbs, close to CBDs or in gated communities single family / apartment. Kitchen, family, living room, dining room, 35 rooms,3-5 baths, 3-6 parking, maidroom , tiled, all services. Mostly detached in suburbs or in gated communities single family / apartment.

Income < 2 MW

2-5 MW

5.5-10 MW

10-26 MW

26-65 MW

>65 MW

Table X Market segmentation in Mexico

2. Background | The Influence of the Vernacular

The socio-economic differentiation can also be measured by the degree of marginalization. This measure differentiates the areas of the territory according to the overall consideration thedeficiencies percentage of dwellings without piped sewage, electricity; also of the impact of the that the population seemswater, to have, as aand result of the lack access education, residence inadequate housing, the perception insufficient ones withto earth flooring (without anyin covering), because this increases the risk of of health problems. monetary income and those related to living in small settlements (Bustos, 2011). It diThe last factor that it counts and that is very common in the country is overcrowding, which means vides the population into five strata: very high, high, medium, low and very low degree of that more than two persons sleep dwellings, in one room.itAccording to this index the results of the degree marginalization. Concerning takes into consideration the percentage ofof dwellings without piped water, sewage,18% andvery electricity; alsohigh, the ones earth16.3% flooring marginalization by municipality indicate: high, 16.6% 38.4%with medium, low, (without any covering), because this increases the risk of health problems. The last factor and 10.7% very low degree of marginalization, with Chiapas and Oaxaca having the most municithat it counts and that is very common in the country is overcrowding, which means that palities degree andinDistrito Federal and Nuevo with very degree. more with than very two high persons sleep one room. According to Leon this index the low results of the degree of marginalization by municipality indicate: 18% very high, 16.6% high, 38.4% medium, 16.3% low, and 10.7% very low degree of marginalization, with Chiapas and OaxaThese types of values and indexes, among others, reflect a quantitative social and ecoca having the most municipalities with very high degree and Distrito Federal and Nuevo nomic of adegree. country’s population; however, they are not necessarily related to the qualLeondistribution with very low

ity of life of the inhabitants. Many of the accounted factors have a negative or positive effect on

These types of values and indexes, among others, reflect a quantitative social and their lives; nevertheless, depending on their interpretation, they are in many cases seen as a measeconomic distribution of a country’s population; however, they are not necessarily relature of progress. However, it is arguably and in some extension, the same kind of progress that was

Table 2 Market segmentation in Mexico. Made by author with information from Softec S.C. (2016) 41

promoted with the ideals of modernity, where excessive consumption overpasses the real needs of the population. This problem of perception in relation to architecture can be seen for example in the building materials, where the use of concrete blocks is classified better as the use of adobe or reed, regardless the climate or the cultural context. Therefore, there is a need to further study the qualitative implications of housing and its effects within the population. In relation to this study, it will be later on demonstrated how are the influence of the vernacular and the quality of life perceived, understood and translated differently depending on the region and socio-economic position of the population.

THE SEARCH OF SUSTAINABLE SOLUTIONS

In Mexico, the new millennium also started with social and political pressure that urged

for sustainable answers to the uncontrolled growth of settlements. On the one hand, The United Nations Framework Convention on Climate Change in 1992 and The Kyoto Protocol in 1997, established several goals and regulations that had to be accomplished by the countries and parties involved to reduce the CO2 and other emissions and therefore global warming starting from 2005 (UNFCCC, 2008). On the other hand, there was pressure produced by an internal market that was not satisfied with the living conditions mainly in urban settlements, which caused 14% of the total dwellings of the country to be abandoned by 2010 (Ziccardi, 2015). As in most of the developing countries with fast population growth, the construction and transport sector contribute to a relatively large proportion of the emissions. In addition, the increasing fossil fuel prices forced the market to search on renewable solutions. All of these have impacted, in many cases, positively the housing sector in the country.

The public sector has introduced different policies that aim to solve some of the before

mentioned problems. INFONAVIT for instance, partnered with several private energy and construction consultants like Passive House, GOPA and GIZ, to implement a series of regulations that force developers to build social housing more sustainably, in order to receive financial benefits and for the consumers to receive financing. Based on an index, they rate from A to G, different aspects related to location, building materials, passive and active low energy systems, and community

engagement among others. This means for example that new developments should be close to services and infrastructure such as schools, medical services, parks, sources of employment, etc. They should incorporate when possible low-carbon materials and passive design strategies depending on the location and climate. They should also add equipment to reduce energy and water consumption (INFONAVIT, 2014). These programmes also seek to increase the coverage of the credits given to lower socio-economic sectors of the population, which gives an alternative to the population that earns less than 2 MW (SEMARNAT, 2017), regularly living in slums. Moreover, they have also implemented initiatives to renovate underused settlements, improving the shared and public spaces, adding services and incorporating systems to reduce energy and water consumption.

The search for vernacular solutions has also played an essential role in the quest to reduce

the impact of climate change. In 2014 INFONAVIT partnered with architects around the country to make 32 proposals, related to the 32 states, for low budget single-family housing. It had the aim to promote a regional design, adapting the projects to the natural and cultural context. The proposals were afterwards complemented by 80 other proposals that were adapted to a specific municipality and to a specific climate that sought to give a base for vernacular self-constructions (INFONAVIT,

2. Background | The Influence of the Vernacular

2018b). It is not the aim of this study to analyze the results of these initiatives, which should be assessed with care before their construction, however, they set an important reference for future housing projects and building traditions in those regions. Two subjective selections can be seen in figure 25 and 26, one that was designed for a community located in the state of Sinaloa in the north of Mexico with hot arid climate, and the other for a rural settlement in the state of Quintana Roo in the south of the country with hot humid climate.

The Mexican pavilion for the 15th exhibition of the Venice Biennale serves as an excellent

compilation of the different efforts that have been lately done in Mexico in regards to vernacular architecture and community building, a crucial aspect of the Mexican culture since the pre-Hispanic era. It was as described by Rafael Tovar y de Teresa, a sample of the work of architects that have understood todayâ&#x20AC;&#x2122;s challenges and have integrated them in different planes with the real needs of society (SecretarĂa de Cultura, 2016). In relation to housing, it showed, for example, the work of Valeria Prieto, whose academic work, has influenced the preservation of vernacular traditions. It also showed projects that in conjunction with the community and studios from different

blisherVersion 0.0.100.100

herVersion 0.0.100.100

Fig. 25

Section of the proposal by Pascal Arquitectos for the state of Quintana Roo (INFONAVIT, 2018)

Fig. 26

Section of the proposal by Casa Publica for the state of Sinaloa (INFONAVIT, 2018) scale 1:100

architecture universities had been built in accordance to a specific context. Finally, it presented the work of different architecture offices like Root Studio, Laboratorio de Arquitectura Básica, Comunal and Arquitectos Artesanos, whose projects have demonstrated how has the influence of the vernacular been applied in contemporary architecture, achieving low-carbon constructions, comfort and life quality. However, as Juan Jose Santibáñez, the leading architect at Arquitectos Artsanos, has suggested, the greatest challenge is that vernacular building traditions can be accepted within the everyday life by a more significant percentage of the population (Santibáñez Garcia, 2008). Therefore to better understand the users should be an important step in achieving this goal.

2. Background | The Influence of the Vernacular

2.5

A PRELIMINARY STUDY ON BUILDING MATERIAL PREFERENCE

Building traditions are highly dependant on the available building materials. As already

explained, one of the disadvantages of using industrialized building materials is their high embodied energy. This means the total energy and total carbon emissions that are involved since the extraction of the raw material, its production, transportation and durability until its end use or disposal. Therefore to achieve a low energy and carbon construction the use of building techniques suited to locally resourced natural materials is primordial (Morel, Mesbah, Oggero, & Walker, 2001; Venkatarama Reddy & Jagadish, 2003). Research regarding this topic is usually carried out from an objective perspective underlining the benefits of using low energy and low carbon materials, but studies on the usersâ&#x20AC;&#x2122; cognition are generally not considered (Zhao, He, Johnson, & Mou, 2015). In Mexico, there is a significant cultural barrier that takes architects, builders, but also public in general away from traditional knowledge and materials. It is normal that people try to adapt their way of life adopting different influences and cultures, rather than the vernacular (SantibĂĄĂąez Garcia, 2008). The use of vernacular building tradition has gained a cultural connotation related to a low social class or to a society that has not progressed, so one hypothesis was that part of this study would display these phenomena.

As architects and planners, we are usually confronted during the building design process

with the actual needs and preferences of the potential users and clients. Therefore, we should consider the social preference of such techniques and materials, and the reasons behind it. A number of studies have addressed the issue by analyzing cases where the architects or designers have primary decision-making authority for material selection (Wastiels & Wouzers, 2008). Nevertheless, there are a significant proportion of constructions worldwide that are done by self-builders or only with the aid of contractors, and therefore the user or developer mainly takes the decisions. In developing countries like Mexico, this phenomenon grows proportionally with the informal settlements; while in countries with developed economies, self-builders emerge looking for alternatives to the mainstream market (Benson & Hamiduddin, 2017; Jeffreys et al., 2014).

Since the 20th century concrete has been established as the primary material used in the

building sector in the country. It is estimated that roughly 70% of the housing constructions in urban settlements and an increasing number in rural areas have it as the predominant material for the envelope (Fry, 2008). Other materials that were and are still used in housing construction are burned brick, stone, adobe, wood and bamboo, reed or straw (INEGI, 2010). Even though glass

2. Background | The Influence of the Vernacular

is not included in the Mexican census as a building material, it has earned popularity as the main façade element, causing an important repercussion in the building’s costs, durability and carbon emissions and it was therefore considered for this study. It has been demonstrated that decisions about characteristics of materials such as physical properties, costs, cultural context and appearance among others are regularly present during the design process while choosing the materials to be used (Wastiels & Wouzers, 2008). However, other environmental factors should be considered; specifically, those related to building materials’ life cycle, such as embodied energy and carbon emissions.

In this study, online questionnaires were carried out based on the hypothetical case of

building a new housing construction. Real behavior was assessed through a speculative scenario, a common methodology in decision research (Kühberger, Schulte-Mecklenbeck, & Perner, 2002). We aimed to answer mainly two questions: (1) Which factors most influence the decision-making process of people while choosing building materials? (2) How do people update their preferences after acknowledging facts about the chosen materials?

THE STUDY

100 participants living in Mexico partook in the study. The participants were recruited

through the crowdsourcing online platform Clickworker (www.clickworker.com). Internet-based studies have demonstrated to be as accurate as laboratory experiments in behavioral research, plus it allows access to a large volume of subjects (Crump, McDonnell, & Gureckis, 2013). The sample was limited to the users of this platform, which were mainly economically active adults. We decided not to exclude any participant based on previous knowledge, location or other demographic factors since these variables could not correlate with the randomized conditions by design (see below). The survey took approximately 5 minutes to complete and the minimum time threshold for valid results was 2 minutes (participants who completed the study in less than 2 minutes were excluded from analyses).

After a series of demographic questions, participants were asked to give information about

their type and condition of dwelling and if they would rely on an architect, a contractor, family or just on their own while building a new house or building. For the next phase, preferences regarding different materials that are commonly used on the buildingâ&#x20AC;&#x2122;s substructure and in the shell as exterior and interior finishes were elicited. Regardless of the configuration, a buildingâ&#x20AC;&#x2122;s embodied impact concentrates on the materials of the substructure and the cladding of the shell (Basbagill, Flager, Lepech, & Fischer, 2013). Participants were asked to rank these materials in order of preference for the exterior of their dwelling. They were also asked to rank the factors that affect their choice of material the most, among physical properties, costs, cultural context, appearance, and environmental factors. The study then included an experimental section. After indicating their choice, the participants were randomly assigned to one of four groups.

A standard construction of one square meter of the shell of a building was compared based

on four factors: typical durability (physical property), price (costs), trend (cultural context) and embodied carbon emissions (environmental factors). The four factors that were randomly shown to the participants can be seen in the following figures:

Typical durability of building materials stone

concrete

Building material

ďŹ red brick

wood

glass

adobe

reed/straw

Typical durability (years)

Average price of materials per m2 reed/straw

adobe

ďŹ red brick Building material

concrete

wood

stone

price / m2 ($/m2)

Fig. 27

Typical durability of materials. Made by author with information from eTool (2017)

Fig. 28

Average price of materials per m2 in Mexico. Made by author with information from Insucons (2018)

2,000

1,800

1,600

1,400

1,200

1,000

800

600

400

glass

200

2. Background | The Influence of the Vernacular

Predominant material in walls concrete

ďŹ red brick

Building material

stone

adobe

wood

reed/straw

45%

40%

30%

25%

20%

15%

10%

glass

percentage of dwellings (%)

Embodied carbon emissions reed/straw

adobe

Building material

wood

stone

concrete

glass

carbon emissions (kgC/m2)

Fig. 29

Predominant material in walls in Mexico. Made by author with information from INEGI (2016)

Fig. 30

Embodied carbon emissions. Made by author with information from Hammond & Jones (2008)

100.0

90.0

80.0

70.0

60.0

50.0

40.0

30.0

20.0

10.0

ďŹ red brick

After receiving the information, the participants were finally asked once again to rank the

materials according to preference to measure their update in preferences after seeing the information provided to them in each condition. Based on a previous study (Sunstein, Bobadilla-Suarez, Lazzaro, & Sharot, 2016), we entered the results into an analysis of variance (ANOVA) with fact type as a between-subjects factor with four levels (trend, durability, price, and carbon emissions) with participantsâ&#x20AC;&#x2122; update as the dependent measure. The estimation errors were defined as: 1-(Pearson correlation of first estimate with the presented fact in each condition). We also analysed how the influencing factors are related to other covariates such as gender, age, and income level with a follow up analysis based on multiple linear regression.

THE RESULTS

The specific characteristics of the participants living in Mexico were as follows: gender:

68 males and 32 females; age: 54 were 18-29 years old, 42 were 30-49 years old, and 4 were 50-64 years old; occupation: 20 were employed in education or health, 32 in technical or professional

2. Background | The Influence of the Vernacular

services, 3 in farming, fishing or forestry, 7 in sales or tourism, 11 in construction or maintenance, 3 in production or transportation, 4 in the government, 2 worked as freelancers, 23 were students and 4 were unemployed; household monthly income: 4 earned less than MXN 2K, 4 earned MXN 2K-3.9K, 6 earned MXN 4K-5.9K, 22 earned MXN 6K-9.9K, 28 earned MXN 10K-$19.9K, 26 earned MXN 20K-$49.9K and 9 earned more than MXN 50K; type of home: 69 were living in a single family-house detached, 19 were living in an apartment in a multi-storey building, 7 were living in a multiplex house (row house, duplex, triplex, etc.) and 4 were living in a vecindad. The average household size reported by the participants was 3.37 persons per unit.

When hypothesizing about building a new house or building, 63 participants reported that

decisions regarding building materials would solely be taken by their own or a family member, 19 would also include an architect or a contractor in the decision-making process and only 18 would leave the decision exclusively to the architect or contractor. When ranking the materials of preference that they would use the most on the shell of their dwelling, these were:

1.Concrete (x 2.31, s = 1.79)

2.Fired brick (x 2.9, s = 1.79)

3.Stone (x 3.26, s = 1.4)

4.Wood (x 3.83, s = 1.38)

5.Adobe (x 4.49, s = 1.75) 6.Glass (x 5.13, s = 1.67)

7.Reed/Straw (x 5.82, s = 1.55).

When ranking the factors that affected their decision the most, these were:

1.Physical properties (x 1.91, s = 1.15)

2.Costs (x 2.61, s = 1.28)

3.Appearance (x 2.64, s = 1.25)

4.Environmental factors (x 3.57, s = 1.08)

5.Cultural Context (x 4.14, s = 1.13).

The results were entered into a one-way ANOVA (see Fig. 5). For this model, the be-

tween-subjects factor of fact type was significant (F(3, 95) = 5.108, p = 0.003, partial eta squared = 0.139) and so was the estimation error nuisance variable (F(1, 95) = 8.132, p = 0.005, partial eta squared = 0.079). After observing the fact that was randomly selected for each participant, the rankings of materials slightly changed as a reaction to the new acquired information. The group that expressed a more significant update of preference was the one that observed the information about carbon emissions. Therefore, the fact that had the most influence over the participantsâ&#x20AC;&#x2122; update was the environmental factor, followed by the physical property (durability), the cultural context (trend) and price, as it can be seen in figure 31.

To follow up on these results, a series of multiple linear regressions were implemented

with the backward elimination method (see (Draper & Smith, 2014)) in SPSS. The full model included as predictors the estimation error nuisance variable, gender, age, income level, the five influencing factors (i.e., physical properties, costs, cultural context, appearance, environment), and three of the four independent variables (i.e., durability, price, carbon emissions) using the trend

Estimated marginal means of update .60

2. Background | The Influence of the Vernacular

Estimated marginal means

.50

.40

.30

.20

.10

0.0 durability

price

trend

carbon emissions

fact

Fig. 31

Estimated marginal means of update for each condition given by fact type (durability, price, trend and

carbon emissions). The error bars are 95% confidence intervals of the marginal means.

variable as a baseline for the model. The best performing model resulted in one with age (B = 0.01, t = 3.063, p = 0.003, 95% CI = [0.004, 0.017]), price (B = -0.255, t = -3.85, p < 0.001, 95% CI = [-0.387, -0.124]), and estimation error (B = 0.267, t = 5.026, p < 0.001, 95% CI = [0.162, 0.373]), as predictor variables. Care should be taken when interpreting these effects due to the multiple comparisons nature of the backward elimination method.

THE CONCLUSIONS

The current building traditions in Mexico are correlated with its pre-colonial, colonial and

post-colonial history; however, most of the building techniques are dependent on practices that developed with modernity and with the use of cement. Therefore with this preliminary study, we wanted to research on the factors that could influence the potential use of natural materials and vernacular building techniques in the future. Thus it was focused on possible decision-makers in the building industry within the national context, regardless of occupation or previous knowledge. The results of the surveys show that 63% of the participants would rely on their own decisions while choosing materials to build a new housing construction. This number is related to the high rates of self-construction in the country and shows the importance of this market. The results also show that concrete was the highest ranked among the preference of building materials and as expected, the ranking followed the same patterns from the national census, which as previously stated favours the use of industrialized materials.

The findings express that physical properties, such as durability and resistance, were by

far the most influential factors reported by the participants when choosing a material. This can be explained because the search of these characteristics is embedded in a cultural context of a society that is greatly concerned on a false idea of progress and in some regions to bad experiences related to earthquakes. This is for example how concrete industries established in the market, as suggested by Walker (2000), using these characteristics for its propaganda. Nevertheless, the update in preference was influenced more by other factors. For example, acknowledging evidence concerning carbon emissions of materials can have a more significant influence on the update of preference in comparison to other types of evidence like durability, trend or price. The latter had

almost no influence on the participants’ update of preference. These results could be explained, because the Mexican society is more and more concerned about climate change and environmental factors, however, it can also be suggested that they are a consequence of confirmation bias. This theory states that recognizing information about an existing belief generates less influence on our change of mind than on receiving information about something which we know less (Nickerson, 1998). In the case of Mexico, there is less information about carbon emissions, than there is for example about the prices of building materials. According to a study by Rohracher & Ornetzeder (2002), environmental awareness is directly related to the economic level of the population. This could explain the high influence that this factor had on the participants’ preference, however, this question will be resumed with the case studies in the next chapters.

This study could serve as a basis for material producers to understand the factors to focus

on while developing a sustainable product, similar to what the cement industry did during the 20th century. The findings of the study show that focusing on information that is not common for the decision-makers might result in a higher influence for the update of preferences. This might also have implications for policy makers, to know on what factor to focus on promoting the use of

2. Background | The Influence of the Vernacular

low-carbon building materials. In the case where architects and planners are involved in the decision-making process of constructions, it is primordial to have a better understanding of the clients’ needs and preferences and to know what type of information has more influence over the clients’ decisions, in order to promote building techniques suited to locally resourced natural materials.

A goal from this study was to dig into the previously mentioned challenges that vernac-

ular traditions will have in Mexico while trying to overcome social barriers in the building sector. Thus, it serves as a preliminary approach within a national context. However, the use of building materials related to building traditions has to be analysed within a more local context and a specific climate. There are also other variables that could be considered depending on what is measured, like supply and availability of materials, aesthetic attributes, or specific building regulations, as users’ choice may vary greatly depending on the location. This is why on the next chapters I will further focus on specific housing examples from the 21st century, in which different building techniques and materials were used for their construction. Two regions will be assessed, one with arid climate and the other with tropical climate. This allowed me to have a more personal approach

with the users, which led to further conclusions, not only about the use of low-carbon building materials but also about aspects of comfort and life quality, which are also directly connected to the building traditions of the country.

3 CASE STUDIES HOUSING ANALYSIS ACCORDING TO SOCIO - CULTURAL FACTORS, SITE, CLIMATE, MATERIALS AND TECHNOLOGY

Nowadays, dwellings are built by following different patterns, which have so many inter-

connections and variables that they hinder the study of building traditions. As before explained, these patterns have shifted throughout time, from solving the basic needs of society into complex structures influenced by a significant amount of factors. Amos Rapoport (1969), suggested that the factors that define the dwellings could be classified into three groups to simplify their study. The first, are the socio-cultural factors, which are not explicitly related to the constructions or the physical environment, such as rituals, religion, socio-economic structure, social relations, and values. The second group are the physical factors related to the natural environment, including climate and the building site, like temperature, humidity, light, precipitation, air movement and vegetation. The third group includes factors that are related to both social and natural environments and that refer directly to the construction, like availability of materials and technologies.

This classification served as a base for a study that was performed to assess the influence

of the vernacular in the current building traditions in Mexico. Two case studies were selected to give an example of two regions in the country, which developed by fol-lowing different patterns. This first part of the study follows an interpretative-historical, typological and physical analysis that will give an objective and quantitative perspective to the reader. This chapter then shows a contextual overview of the natural and cultural factors that affected the building traditions in both of the case studies. Then, through the assessment of different housing typologies, an evaluation is presented regarding their building techniques, orientation, form, indoor microclimate and other physical characteristics that might affect the comfort and life quality of its occupants. However, in addition to the methodology that is suggested by Rapoport, this study also considered the response and opinion of the occupants that was part of the field research, and which assessment will be presented together with the overall results as part of the next chapter.

Fig. 32

19th century house in Garcia, Nuevo Leon. Taken by author

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3.1

THE STUDY

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102

There are significant differences in Mexico between the north and the south that corre-

spond, as explained before, to a cultural division that was mainly caused by the geographical and climate conditions of both areas. The north, distinguished by its arid environment and lack of water, remained for an extended period an isolated region with less cultural development than the south. Nevertheless, mainly due to its proximity to the United States border, the north presented a very fast development after industrialization. The south, with a slower economic development and a more considerable degree of marginalization, kept a more traditional character, also related to the vast indigenous past. These differences can also be perceived in the building traditions and the development of the housing sector. Therefore, this research is focused on one case study from the north and one from the south to better understand the influence of the vernacular in the building traditions of a particular context and their effect on the occupants.

DEFINITION OF THE CASE STUDIES AND SAMPLES

The definition of the cases studies was dependent first on the climate and second on find-

ing two regions that represent the earlier described characteristics from the north and the south of Mexico. The first case study representative of the north, which is located within an arid climate, is the Monterrey Metropolitan Area, in the state of Nuevo Leon. It is the third largest metropolitan area and one of the richest, industrialized and â&#x20AC;&#x153;Americanizedâ&#x20AC;? cities of the country (Contreras, 2009). The second case study representative of the south, which is located within a tropical climate, is the region called Istmo de Tehuantepec, in the state of Oaxaca. In comparison to Monterrey, it is a region with a much slower economic and industrial development, and its customs and traditions are much more rooted in local culture (Jimenez Vera, 2012).

The different socio-cultural and physical factors that influenced the building traditions of

the case studies were studied and related to the previous historical analysis of the national context. Then, through a series of mappings, following a study from Aparicio-Moreno (2012), areas with high levels of economic contrast were selected. This information was visualized using the Geographic information system (GIS) software called Map-Info, using information from the National Population Census of 2010. The mappings showed the degree of marginalization, which was an important parameter because the typologies or samples to be studied were classified according to the socio-economic status, one of the most important factors defining the building traditions and the life quality in Mexico (Ziccardi, 2015). These mappings were overlapped with information regarding climate and different physical factors, which helped us to determine three municipalities per case study for further analysis with field research.

The samples in this part of the study refer to the specific housing typologies that were as-

sessed to exemplify the current building traditions in each of the case studies. Given the relevance of the proportion of single-family houses in the country (92.2%), we decided to focus on this type of dwelling. Three samples were selected per municipality. After visiting the areas with high socio-economic contrast and speaking to the community, the samples were selected according to the building techniques and materials. Given the few cases where vernacular techniques and materials

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were used for the construction, they were known by the community and represented the primary parameter to have a selection of samples. The samples were then classified according to the market segmentation that was explained in the previous chapter, but which can be found once again summarized in table 3. In every municipality, the goal was to analyze one dwelling and household from a low socio-economic class, represented for this study by the economic, popular and traditional types and one from a high socio-economic class, represented by the middle, residential and summarized in figure X. In every municipality, the goal was to analyze one dwelling and residential-plus types. The third sample to class, analyze in every municipality was abyconventional type, household from a low socio-economic represented for this study the economic,

popular traditional types and one where from athe high socio-economic class, represented which was and determined by selecting a case primary building material was concrete,by rethe middle, residential and residential-plus types. The third sample to analyze in every gardless of the market segmentation. municipality was a conventional type, which was determined by selecting a case where the primary building material was concrete, regardless of the market segmentation. Type

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Area

Characteristics

Income

Economic

< 30 m²

Mostly self-built detached or in slums

< 2 MW

Popular

30 - 50 m²

2-5 MW

Traditional

50 - 75 m²

Middle

65 - 130 m²

Residential

65 - 150 m²

Residential-plus

100 - 350 m²

Mostly mass social housing or self-built Mostly mass social housing, self-built detached or close to CBDs Mostly self-built detached, close to CBDs or in gated communities Mostly detached in suburbs, close to CBDs or in gated communities Mostly detached in suburbs or in gated communities

5.5-10 MW 10-26 MW 26-65 MW >65 MW

The Field Research

THE FIELD RESEARCH Nine housing typologies were selected per case study, eighteen in total, to be further analyzed and compared. After the consent of the occupants, the field study consisted of collecting information regarding the different factors that defined the dwellings, and that might Nine have housing typologies were per case eighteen total, to be further anasome influence inselected the comfort andstudy, life quality ofinthe users. Concerning the construction, wereoftaken, and analyses of the building techniques and lyzed and compared.measurements After the consent the occupants, the field study consisted of collecting materials were done with the aid of the residents in order to elaborate floor plans and information regarding the different factors that defined the dwellings, and that might have some sections for their study. In relation to climate, in addition to the plans, comfort measinfluence in the life performed quality of the users.relate Concerning the construction, measurements urements andcomfort surveysand were which the physical environmental conditions of the outside andofinside of the dwellings be materials further correlated thethe occupants’ were taken, and analyses the building techniquestoand were donetowith aid of the response to them. Finally, regarding some of the socio-cultural factors that might repreresidents in order to elaborate floor plans and sections for their study. In relation to climate, in sent the influence of the vernacular in the building traditions, a photographic survey of addition to the plans, comfort measurements surveys performed which relate the physithe surrounding and the image of the cityand were usedwere to interpret the aesthetical factors that were reflected in eachofofthe the samples. interviews were carried outto cal environmental conditions outside and Also, insidequalitative of the dwellings to be further correlated with the occupants to determine their understanding of their building traditions and the effects of the built environment in their quality of life. Table 3 Market segmentation summary. Made by author with information from Softec S.C. (2016) One of the functions of the built environment is to create an internal microclimate different from the outside. The aim of the physical measurements that were performed in each dwelling was to determine the relation of the indoor and outdoor climates. For such measurements, the study was based on the method proposed for the adaptive thermal comfort approach by M. Humphreys and F. Nicol in 1972, and that has been subsequently developed since then (Nicol, Humphreys, & Roaf, 2012). According to that approach,

the occupants’ response to them. Finally, regarding some of the socio-cultural factors that might represent the influence of the vernacular in the building traditions, a photographic survey of the surrounding and the image of the city were used to interpret the aesthetical factors that were reflected in each of the samples. Also, qualitative interviews were carried out with the occupants to determine their understanding of their building traditions and the effects of the built environment in their quality of life.

One of the functions of the built environment is to create an internal microclimate differ-

ent from the outside. The aim of the physical measurements that were performed in each dwelling was to determine the relation of the indoor and outdoor climates. For such measurements, the study was based on the method proposed for the adaptive thermal comfort approach by M. Humphreys and F. Nicol in 1972, and that has been subsequently developed since then (Nicol, Humphreys, & Roaf, 2012). According to that approach, Level II measurements were performed on each of the housing samples to determine the indoor and outdoor air temperature, surface temperature, relative humidity, illuminance and air velocity. These are the factors that have a physical influence over the comfort of humans. Thus the results of such measurements were used for the next part of the study to relate them with the occupants’ satisfaction. The indoor equipment was placed in the centre of the room that was used the most by the occupants in each of the samples. The outdoor equipment was placed under a shadow. The study was performed in some of the warmest periods of the year for each of the regions. In the case of Monterrey, the field research was carried out during August and in Istmo de Tehuantepec during September of 2018. The study in each sample was also carried out during the warmest hours of the day, in between 1 and 4 pm, as one of the goals was to determine the relation of the dwellings to the hot climate conditions during the worst-case scenario.

Comfort can be defined as the physical and mental state in which humans express sat-

isfaction with their surrounding physical environment. In architectural studies, this concerns everything related to the indoor qualities of the space. In that sense, from a quantitative approach and following the methodology from the adaptive thermal comfort model, the occupants’ comfort can be measured with the aid of a comfort survey (Brager & de Dear, 2001). For this part of the study, we surveyed one adult occupant per sample. Before carrying out the survey, the occupant

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was asked to manipulate the building components of the house like windows, doors, and blinds, as they would typically do, but without using air conditioning or any mechanical systems. After a series of demographic questions, they were asked to state their level of satisfaction or dissatisfaction on a 7-point sensation scale in relation to the space where they spent most of the time in their house. Then they were asked to state the factors for dissatisfaction. Finally, they were asked to state if their comfort level affected their quality of life and how, which took the survey into the second part of the study with the occupants, which were qualitative interviews.

The qualitative part of the study consisted of structured interviews that aimed to un-

derstand the relation between the built environment and the occupant’s quality of life and their knowledge regarding vernacular building traditions and sustainability. Following the study by Ziccardi (2015), in which the factors that influence the quality of life in housing construction according to different regions in Mexico were analyzed, this part of the study complements their findings by focusing on a specific context. The interviews were based on four questions; however, if necessary, remarks were made allowing further exploration on the topic after the participant’s responses. The four questions were: (1) What means quality of lie to you? (2) Which aspects of your

3. Case Studies | The Influence of the Vernacular

106

neighbourhood have an effect on your quality of life? (3) Do you think that the way in which your house is designed and built has an effect on your quality of life? In what sense”? (4) What means sustainable architecture to you? The surveys responses and critical answers and aspects within the interviews were transported into a matrix that allowed a detailed comparison of the samples per case study and also a comparison between both of the case studies. As mentioned, the results of this part of the study will be presented in the next chapter.

3.2

CASE STUDY 1 SEMI -ARID CLIMATE: MONTERREY METROPOLITAN AREA, NUEVO LEON

The Monterrey Metropolitan Area (MMA) has a relatively short history in comparison to many

other cities in Mexico. Its urban morphology, which started after colonization, was transformed from being a scattered town into a relatively poor Spanish city and then into becoming after industrialization one of the largest and most important cities in terms of economic development in the country. After the 20th century, the city followed similar patterns to the ones described in the previous chapter, where an uncontrolled growth generated an extended carpet of single-family houses, generally segmented according to socio-economic class and guided by the American dream. This fast growth reflects in the little development of vernacular cultures and building traditions. Cement and concrete frame structures, also accompanied the fast development, filling up the urban landscape. However, there are still some good examples of constructions that have adapted to the different climates and natural resources from the region, and which constitute an essential source for this study to understand how could building traditions develop for the future.

According to the Mexican Census Authority (INEGI), since 2010, the Monterrey Metropolitan

Area is composed of twelve municipalities, as it can be seen in figure 33. The municipalities that were

107

selected for this study, which were the focus of the field research, are García, Monterrey and Santiago, which correspond respectively to the three climates that predominate the region: hot arid (BWh), hot semi-arid (BSh), and humid subtropical (Cwa). Given the different natural conditions, one of the aims of the study was to compare building techniques in the three municipalities and the ways of adaptation to the climate and the immediate context. This region was described in the 19th century by the Mexican writer Manuel Payno as one of the most picturesque and diverse regions of the country in terms of nature, landscapes and architecture (Guerrero Aguilar, 2007). The built environment’s relationship to natural diversity was somehow lost in the 20th century; however, it is a potential that exists and should be considered.

3.2.1 SOCIO-CULTURAL CONTEXT

The socio-cultural factors have dictated in a significant proportion the development of

the Monterrey Metropolitan Area and the configuration of the residential sectors, as well as the form, distribution and aesthetics of the dwellings. It can be argued that many conditions related to the social and economic distribution of the population have been the primary influence of the evolution of the built environment. Since its foundation there has been a division of social groups, first it was an ethnical differentiation, and then it was transformed into a socio-economic division. This unchained other types of phenomena like insecurity and a closed social structure, which were reflected in the housing typologies and the in general in the city, creating a segregated space and society. According to Gonzalez Arellano and Villeneuve (2007), other important dimensions that have structured the socio-residential space in Monterrey is the idea of progress. This dimension is related to the fast economic growth of the region, which attracted population from all over the country competing for job opportunities and searching for the “American Dream”. Immigration generated a combination of different cultural traditions that started to shape the local culture. The influence of the American culture can also be perceived in different aspects from the society’s way of life, including the family structure and the social dynamics, which affect of course the housing typologies.

Fig. 33

Municipalities that form the Monterrey Metropolitan Area (MMA). Made by author with information from

INEGI (2010)

10 km

109

SECURITY AND CLOSED STRUCTURES

The first Spanish groups to arrive in 1577, settled in between to two small water bodies

from the Santa Lucia river and the main river that flows through the region, today called Santa Catarina. Before the arrival of the Spaniards, there were only nomadic tribes, called Chichimecas, living in the region. They were warriors that moved around the region, and they had only temporary constructions. When the conquerors arrived in the region, the indigenous population was either eliminated or taken as slaves. However, for the following decades, there was a constant struggle between the native and the Spanish groups (Guajardo, 1995). The first Spanish constructions reacted to this state of conflict, and the search for protection was the first socio-cultural factor that defined the dwellings from that period, a characteristic that continues to shape the typologies until nowadays.

In 1596 Monterrey was officially founded led by twelve Spanish families. Nevertheless, in

addition to the social conflicts, the extreme climatic conditions and several floods caused by the

3. Case Studies | The Influence of the Vernacular

110

overflow of the river generated a continued development of the settlements. The housing typologies had very few openings to the outside, which were covered with iron protections, also called burglar bars. The closed form not only responded to the Indian attacks but also the hot climate conditions. It was not until the second half of the 18th century that Monterrey started to have an economic growth, which corresponded to the discovery of several mines in its vicinity. It was also then that the urban structure was clearly defined according to the Laws of the Indies. The urban grid started to shape the morphology of the city, but the typologies kept the protective characteristic; closed to the street and opened to the central courtyards. The socio-spatial segregation was also reflected at an urban level. The river became a physical division between the Spanish city to the north and the indigenous settlement to the south (Aparicio-Moreno, 2012). The indigenous groups that were brought from the central region of Mexico represented the labour force that helped to build the new city.

The 19th century, in contrast to the rest of Mexico, represented a time of economic growth

for the MMA. Its distance from the independence war and conflicts region kept it economical-

ly safe. It was even greatly benefited from the Mexican-American War in 1848, which changed the borderline to the United States; a country that was growing exponentially and that opened a new commercial market with Mexico especially through Monterrey. It was then that the hacienda system expanded in the region in the form of industries, with the typical typology of a protected courtyard house for the owners, surrounded by the dwellings of the workers. From that point on, industrialization started to guide the future of the city. The incorporation of the railway and the consolidation of big industries generated exceptional economic growth, which also led to a more significant gap between socio-economic groups. Apart from the haciendas, the first suburbs started to appear away from the Spanish city. They consisted of segregated neighbourhoods for the elite and others for the working class. A steady but slow expansion continued, interrupted by the Mexican Revolution (1910-1917) and the United States economic depression (1930s). However, an enormous development and an uncontrolled urban expansion continued after the 1940s, which also marked the beginning of a polycentric expansion that developed into one of the biggest Metropolitan Areas of the country.

Insecurity became one of the main issues that the MMA faced with its urban expansion.

The increasing rate number of official complaints related to robberies, homicides and sexual crimes grew proportionally or even exceeded the population growth rate since the 1940s. Some of the causes at that time were associated with family fragmentation, the socio-cultural characteristics of the immigrant population, low levels of education and above all the inequality and the impossibility of overcoming the poverty levels of certain groups (Garza & Paniagua, 1995). Lately, insecurity has also been directly linked to drug cartels. Whatever the reason is, it has influenced in a considerable proportion the urban development and the built environment, especially in the housing sector. Fences and dividing walls started to mark a clear differentiation between the public and private space. The single-family houses, which represented the majority of the constructions in the city, can be divided into four typologies, all of them defined by this division or segregation of space.

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SPANISH CITY TYPOLOGY

The first typology was the previously mentioned, built on the perimeter of the block. It

was facing the street but with very few openings that were protected by burglar bars. It sometimes had a central courtyard and if this was not possible because of space a small patio or garden was left behind the construction as shown in the diagram in figure 34. This typology was typical within the high socio-economic class that inhabited the Spanish cities, which can also be defined as the first central business districts (CBD). It then developed as a similar typology within the low socio-economic groups. For example in the slums, because of a lack of space, houses were also built to the perimeter of the streets, also with small openings, protected by fences or any different kinds of lattices.

3. Case Studies | The Influence of the Vernacular

112

Fig. 34

Schematic representation of the Spanish City typology urban distribution. Made by author

SUBURBS TYPOLOGY

The second typology that appeared together with the suburbs and with the increasing use

of cars was characterized by pushing the house back in the building plot or at least the ground floor to leave space to park. Then, part of the faรงade was substituted with gates. Sometimes space was left for a small garden in front of the house, typical of the North American style. If that was the case, the perimeter of the street was protected with a wall or with a fence, also leaving a gate for the cars. By 2015 around 60% of the households in the region had at least one car, which is a very high proportion in comparison to other areas of the country (Ziccardi, 2015). Some variations of this typology can be observed in figure 35.

113

Fig. 35

Schematic representation of the suburbs typology urban distribution. Made by author

GATED COMMUNITIES TYPOLOGY

The third typologies that appeared reacting to the security problems were the gated com-

munities. This configuration, which is also typical from the suburbs, consists of a piece of land surrounded by walls and with restricted access. The land has its own street configuration, and the building land is subdivided in parcels. There are two types of gated communities: the ones where the parcels are sold with already built units, typical from the mass social housing, and the ones that are sold as land, which generally correspond to a higher socio-economic market. This gives, depending on the size of the plots, a certain freedom to the owners and therefore to the housing typologies, which generally follow different kinds of patterns.

3. Case Studies | The Influence of the Vernacular

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Fig. 36

Schematic representation of the gated community typology urban distribution. Made by author

DETACHED TYPOLOGY

The last typology corresponds to bigger pieces of land also surrounded by walls or fences,

but only with one single-family house. This typology is typical from the elite located in the suburbs or rural areas. However, it can also correspond to rural typologies from lower socio-economic classes.

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Fig. 37

Schematic representation of the detached typology urban distribution. Made by author

All of these urban and rural solutions and their variations, which reacted to a pure sense

of security, have contributed to creating a very complex and segregated structure of the MMA. As several authors have noted (Angotti, 2013; Vesselinov, Cazessus, & Falk, 2007) these solutions increase the sense of inequality in the population. They have also become a cycle as they generate more insecurity in the public space. The plazas and streets become unused spaces in between walls, without much activity and surveillance. They also become unattractive spaces for walking, increasing the insecurity again for the people without a car. However, the close urban structures in the MMA as in many parts of Mexico have constituted a significant part of the building traditions since its foundation, and therefore they are part of the vernacular culture. At the same time the urban isolation, together with other types of influences, brought effects in the social relation and the family structure, which will be explained in the next section.

EXTERNAL INFLUENCE AND PROGRESS

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116

The Indigenous and Spanish influence in Monterrey was not as developed as in many

other cities of the country. When the Spaniards arrived, it was not easy for the few new inhabitants to establish as it had been in other regions. From several descriptions of the Spanish city from the 17th century, it can be inferred that it was relatively poor, in comparison to other Spanish Cities in the north like Zacatecas or San Luis Potosi. The economy at that time was based on cattle and the exploitation of small lead and silver mines. Most of the production was done in the haciendas, which were located along the valley. Some of them were also located in Garcia and some others in Santiago. The commercial activities were carried out mainly in the city of Monterrey, which also served as a transit location in between mining routes. The same happened with Garcia that was established as a satellite town close to Monterrey. The mestizo culture was produced by the different groups that arrived from other parts of the country. As there was not a strong pre-existing local culture, immigration and external influences played a primordial role in the growth of the city and the social structure, with a considerable impact in the housing sector.

The Spanish influence, however, as in the whole country, can be perceived in many aspects

of the culture including some aspects of the house. The internal distribution of the houses with the

separation of activities into different rooms comes from the Spanish tradition. By the 17th century, most of the houses had a rectangular shape and a simple distribution consisting of one living space, one kitchen and one or two living rooms (Cavazos Garza, 1995). The zaguán or entrance hall was also incorporated in the most prominent residences. In contrast with other regions in Mexico, religious rituals did not influence the housing typologies and distribution of spaces. As there was almost no influence from the indigenous culture, the rituals also followed the Spanish Catholic tradition. The church was a specific place for the ceremonies, and cemeteries were locations for burials, and the community shared both of them.

As already mentioned, the economic development and population growth in the MMA

started on the second half of the 19th century, together with industrialization, the railway network, and close relation with the United States. By the beginning of the 20th century, Monterrey had been established as a “City of Progress” according to the Mexican press and business leaders from that time (Contreras, 2009). The neoliberal economy that was stated in the country together with the industrial expansion in the MMA, which generated a considerable amount of jobs, produced an atmosphere similar to that of the American Dream. National immigrants from all over the country, but mainly from the neighbouring states, started to arrive searching for new opportunities. Nevertheless, as in many industrial cities from the United States following the same model, the economic benefits were only distributed among a small part of the population, so for a significant proportion, it was not easy to establish. Besides, the housing demand overpassed the supply, and informal settlements started to appear.

According to a study from J. Balan as declared by Zúñiga (1995), with a representative

sample data from 1965, 69% of the adults living in the MMA were immigrants. From that total, 70.1% arrived from the neighbouring states, mainly from San Luis Potosi, Coahuila, Tamaulipas, and at last Zacatecas. These groups usually represented the lower strata of the socio-economic distribution. Thus, the mestizo influence can be perceived more within these groups. The American influence was more notorious within the high socio-economic classes. The relation is closer because these groups of the population go and come back from the northern country for holidays, school and business. In Monterrey, there are more American shops and companies than in any other city in Mexico, and even companies established in the MMA share the ideals of the US busi-

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ness sector, as most of their owners have studied in that country. Lorenzo Zambrano, the owner of CEMEX, one of the biggest cement companies in the world, once stated in an interview: “Mexico isn’t Latin America, Mexico is North America, and that’s the end of the discussion”. The supremacy of the private sector in the region with American influences contributed in a great way to the urban development of the city, and the housing typologies. On the one hand, by transmitting the consumption ideals to the population, for example with building materials such as cement and steel. On the other hand, the elite groups started to import traces of what was trendy in the northern country. Gated communities and housing suburbs filled up the urban sprawl. Shopping streets and malls became the central gathering spaces, and the segregation between social classes became even more notorious (Contreras, 2009).

Social status, which is represented by material possessions, became a pillar in the search

for progress. Owning a single-family house, a car, and achieving independence from the parents would become primordial steps in achieving this goal. A statistic that reflects it is that in 1950 only 37.2% of the dwellings were occupied by their owners and in 2010 this number increased to 85.4% (INEGI, 2010). Public programmes of regularization of informal settlements, which started in the 1970s (Villarreal G., 1995), also al-lowed this number to be so high in comparison to the country’s housing property average of 72.3%. However, it reflects the aspirational mentality of the population. Another number that is above the national average (92.2%) is the percentage of single-family houses: in the municipality of Monterrey, it is 93.7%, in Santiago 97.8%, and Garcia 99.3%. The socio-economic disparity within these three municipalities increased together with the urban sprawl, which can be observed in figure 38. In contrast with other regions of the country, the size of the houses is also bigger. According to the study by Ziccardi (2015), which took a representative sample of houses from different regions in Mexico, the houses in the Northern area of Mexico are bigger; where 47.8% of the houses have more than 75m2 whereas in the south only 16.3% have more than that area.

Apart from the presented facts and suggestions from other authors, the influence of im-

migrants and from the US culture in the housing sector cannot be generalized. It is clear that it affected the social characteristics of the population like the family structure and the social relations among and between the different socio-economic groups; which created a different social

Fig. 38

Level of marginalization in the MMA. Made by author with information from INEGI (2010)

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Climate Hot arid (BWh) Hot semi-arid (BSh) Humid subtropical (Cwa)

dynamic from the rest of the country. As stated, this affected the urban development of the MMA, but also specific characteristics of the housing typologies. Some of these include the size, the internal distribution, the materiality and many other aspects related to the aesthetics. The analysis of the specific cases according to municipality will help to clarify some of the influences that were mentioned. Apart from these socio-cultural influences, there are also physical characteristics from the region, which will be explained next and that affected the development of the building traditions of the Monterrey Metropolitan Area.

3.2.2 SITE AND CLIMATE

The physical characteristics of the region and its climate have significantly influenced

the development of the urban sprawl and in some extension the typology of the constructions. One of the main characteristics of vernacular architecture is the capacity of adaptation to the local natural context, and therefore the analysis of such conditions is primordial to understand the past and potential influences for the housing sector. The MMA is located on a region with three physiographic regions: the valley, the hills and the mountain ranges (Barbarín Castillo, 1995). The valley is where the Spaniards first settled and where most of the built environment has developed, close to the rivers and streams that flow through the region. The hills, even though they represent a physical limitation, they have been almost swallowed by the urban sprawl. The mountain ranges do represent the physical barrier that has given shape to the urban environment; however, a large amount of area from the mountain skirts has also been already constructed over.

In relation to climate, the MMA is precisely located in a climate transitions zone in be-

tween hot arid and humid subtropical areas. Its location along a valley generates a mixture of hot arid and hot, humid air circulation and pressure. The first circulation comes from the Coahuila Desert on the northwest, and it is predominant during late autumn, winter, and spring. The second one comes from the Mexican Gulf on the South East (Limón Rodríguez & Leal Iga, 1995) and

Fig. 39

Climate in the MMA. Made by author with information from INEGI (2010)

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Average temperature per hour in Monterrey. Made by author with information from Venture (2019)

Fig. 41

Maximum and minimum average year temperature in Monterrey. information from Venture (2019)

Fig. 42

Average wind speed in Monterrey. Made by author with information from Venture (2019)

is predominant in summer and the beginning of autumn, which correspond with the period with precipitation. Due to this condition, the MMA has characteristics from dry and humid climates. The presence or lack of water has represented a problem since the foundation of the city.

The great extension of the urban sprawl with around 74 km on its longest distance makes

it possible to spread along the three predominant climate zones of the region: Hot Arid (BWh), which corresponds to the municipality of Garcia, Hot Semi-Arid (BSh), which corresponds to the municipality of Monterrey, and Humid Subtropical, which corresponds to the municipality of Santiago. Even though the climate patterns are very similar given their proximity, there are some variations. These small variations affect the comfort perception of humans directly, and therefore they should also be reflected in the design strategies that should modify different aspects of the housing typologies in each of the municipalities.

TEMPERATURE

The temperature ranges are almost the same in the three cities with average variations

of around 12°C between day and night. During summer temperatures frequently reach more than 35°C, and during winter it can regularly drop to less than 10°C. Thus, if we take a thermal comfort range between 20°C and 24°C, the most uncomfortable periods of the year concerning temperature are during most hours of the days in summer, and during the nights in winter.

WIND

The predominant winds are directly related to climate circulation, which was previously

mentioned. The winds from the north and northwest that come mainly from the Coahuila desert are predominant from November until February, while the winds coming from the coast, from east and southeast are predominant for the rest of the year. The average wind speed is almost constant ranging from 2.5 m/s to 4.0 m/s.

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Sun path in Monterrey. Made by author with information from Sun Earth Tools (2019)

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Comfort according to humidity in Monterrey. Made by author with information from Venture (2019)

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Average rainfall in Monterrey. Made by author with information from Venture (2019)

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SOLAR RADIATION

The solar radiation, which is dependent on the sun movement, is higher in summer reach-

ing an average of 7.5 KWh/m2 and lower in winter with an average of 3.9 KWh/m2. Because of the MMA location in the latitude 25º 45’, the sun is almost all the time in the southern sky reaching its lowest point in the winter solstice with a solar elevation angle of 42º and its highest point with 88º in the summer solstice.

DEW POINT, HUMIDITY, AND PRECIPITATION

The most considerable difference among the three cities is their dew point levels, which

is what makes the differentiation between dry and humid environments and that also affect the comfort of humans considerably. The dew point is the temperature at which air needs to be cooled down in order to condensate; therefore it also determines the evaporation point of sweat from the skin, which has the function of cooling down the body. The lower the dew point, which is the case of Garcia, the drier it feels. The higher the dew point, which is the case of Santiago, the more humid it feels, also affecting the levels of precipitation (Ventures, 2019). The average total accumulation of rainfall in Garcia is 85 mm, in Monterrey 97 mm, and in Santiago 107 mm. This difference in dew point is why even though the temperatures are similar between the three cities the perception for humans is not the same. This difference can also be more clearly perceived in the vegetation and the soil, with the desert region to the west and a greener region to the east.

ADAPTATION TO THE SITE AND CLIMATE

In general terms, with some exceptions, the built environment in the MMA has not been

adequately adapted to the natural context. First of all, since its foundation, the management of water has represented a problem. On the one hand, the long periods without precipitation and in-

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Situation Map Topography line River Underground river Highway Train track

correct management of the water resources has caused droughts during several periods, affecting not only agriculture and industries but also the water supply in the housing sector. On the other hand, the intense rains in summer, which are affected by the formation of hurricanes on the Gulf of Mexico, have caused the overflow of the rivers on several occasions. The Spanish city, for example, had to be re-built and relocated several times because of this reason. This condition mainly affected the building sector before the construction of the dam system that started in the 1950s (Esparza Hernandez, Valdés Lozano, Cantú Martínez, & de la Mora, 2014); however, there are still areas of risk close to the water bodies that are still affected until nowadays. The last two hurricanes that caused numerous damages due to the overflow of Santa Catarina River were registered in 1988 and 2010. In relation to the typologies, the reaction to the low levels of precipitation has been the use of flat roofs since the first constructions appeared. The storage of rainwater has never been a characteristic of the typologies; however, it still represents a potential mainly during the humid season to store for use during the dry season.

On an urban level, the adaptation to the terrain and topography has also presented diffi-

culties in several regions of the metropolitan area, mainly due to the fast and uncontrolled urban expansion that started since the second half of the 20th century. In the 1950s the population in the MMA had around 500,000 inhabitants distributed in around 5,000 hectares, and by 2015 it had 5.1 million inhabitants distributed in around 100,000 hectares (Flores, 2017; Garza, 1998). That means that the population multiplied by around ten times but the urban sprawl expanded by around twenty times. By the 1980s the urban sprawl had reached the natural limits to the west and south. The hills were partly built mostly by irregular settlers; however, developers also saw the opportunity to exploit the views of the valley by developing gated communities higher in the terrain (Ortega García, 2001). Altitude and inaccessibility added another level of complexity for the introduction of infrastructure and also for the housing typologies. During the 1990s and 2000s, the expansion continued through the valley to the northeast and around and over the hills and mountain skirts in every other direction.

Finally, in the typological level, the adaptation to the climate is hardly perceived in the

MMA. The extreme climate conditions generate discomfort for humans most of the time while being outside. According to regular values from ASHRAE 55, a standard that predicts comfort based

Fig. 46

Situation map of the MMA with topography, urban sprawl and rivers. Made by author with information

from INEGI (2010)

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Fig. 47

Psychrometric chart and design strategies of outdoor measured yearly values in Monterrey. Made by author

with information from Milne (2018)

on temperature, clothing level, metabolic activity, air velocity, humidity, and mean radiant temperature, only around 13% of the time the MMA has comfortable levels for the majority of the population (values were taken with the aid of the software Climate Consultant; see (Milne, 2018)). That means that one of the purposes of the built environment should be to help the users to meet comfortable conditions for the other 87% of the time. The indoor comfort can be achieved by using different design strategies that can naturally keep a temperature and humidity balance inside of the constructions. For the diverse conditions of the MMA, these strategies can slightly vary, for example in the case of the three studied municipalities that have different humidity levels. Some of these strategies, which are much dependent on the natural surroundings, the form, the orientation and the envelope of the house, have been used since the foundation of the city; however, as stated by different authors (Esparza Hernandez et al., 2014; King, n.d.), with the fast growth of the housing sector during the 20th and 21st century, they have been left behind.

Given the temperature conditions of the three municipalities, the comfort strategies to be

followed can be divided into two periods. The first one corresponds to the colder and drier period between November and March and the second one to the hotter and more humid period between April and October. The basic principles for comfort that can be achieved in different ways are to promote heat gains for the cold period and to avoid them and to enhance ventilation for the hot period. The only difference between design strategies in Garcia, Monterrey and Santiago would rely on various ways to control humidity; however, when analysing the three climates in a psychrometric chart, the variations do not represent any significant change on the predicted comfort of the users. Thus, the following design strategies for housing typologies can be and have been applied for the entire Monterrey Metropolitan Area. The psychrometric chart in figure 44 shows the measured year values of the centre of Monterrey according to temperature, relative humidity and humidity ratio. To achieve comfort for all the values that are outside of the comfort zone, there are several passive and active design strategies that can be implemented, which are shown by the different colored areas.

One of the strategies to control heat gains and ventilation depends on the orientation

of the dwellings. The ideal orientation for these climate conditions would be predominantly to

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the south, which minimizes the sun exposure through the openings in summer and maximizes it in winter. Depending on the sun inclination, overhangs, any shading device, or even trees can be used during hot periods to reduce the exposure. The openings to south and southeast orientations are also ideal because prevailing winds in summer come from that direction. As dew points are higher during that period, the wind in combination with the evaporation of sweat generates a cooling effect on the body, therefore enhancing the sensation of comfort. This strategy is clearly not always possible to follow, as many conditions can influence the orientation, mainly within the urban context. The cardinal orientation of the urban tissue in Monterrey started by following the grid imposed by the Laws of Indies, which allowed many of the buildings in a block to have a south orientation. In the 20th century, the urban tissue started to follow other patterns like the limits of the haciendas, the rural roads that adapted to the topography and the train lines, which started to create a chaotic network (Aparicio-Moreno, 2012). Later on, like in the case of Santiago, the settlements extended together with the direction of the highways and the valley, so the orientation according to the sun and wind were in most of the cases not taken into account.

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Given the extreme temperatures and their fluctuation between day and night, other com-

fort strategies are the use of building materials with low thermal conductivity and high thermal mass. Thermal conductivity is related to the heat transmittance between the outside, and inside temperature, thus, it relates mainly to the envelope of the constructions. Low thermal conductivity in a house can also be expressed, as insulation. In the MMA this strategy is more useful in the cold period if there is no use of mechanical systems, as the openings are more likely to remain closed. Thus, if heat gains are endorsed on the inside, it is easier to prevent heat transmittance to the outside. In summer it is more challenging to avoid heat gains on the inside if there are no cooling strategies; as natural ventilation usually is promoted, the inside and outside temperatures remain similar. Therefore, the heat transmittance between inside and outside is minimized. If heat gains are not controlled on the inside, the insulation of the house can even create a contrary effect by not allowing the heat to go out and contributing to overheating of spaces (Wassouf, 2014).

The use of high thermal mass materials is related to their heat storage capacity, and there-

fore it relates to all the materials that are used for the envelope and interior components. Regard-

less of the period of the year, heat is stored during the day in the material, when high temperatures are regular, and it is released with lower temperatures at night. Therefore it is an excellent strategy for this region. However, in summer it also works better when combined with cooling strategies. In the MMA the use of clay tiles, sillar and adobe were widespread before industrialization. These materials, based on clay and rock, have relatively good insulation and thermal mass values (Fathy, 1986); however, their use was almost entirely replaced by reinforced concrete and hollow concrete blocks during the 20th century. This replacement not only affected the interior comfort of the dwellings but it also considerably increased the embodied energy of constructions. The specific characteristics of building materials and their availability in the MMA will be further explained in the next section.

Given the difficulties of avoiding heat gains during summer, passive cooling strategies

are needed to achieve a comfortable indoor environment for the users. The most common strategy in the MMA is the use of courtyards. The Spaniards imported the courtyard typology, but its influence, with different variations, has been part of the building traditions in the region until today. Its primary function concerning comfort is to create a microclimate different from the usual ambient conditions. In order to better do so, the courtyard has to remain shaded, and trees are typically used for this reason. In the Spanish typology (Spanish Cities and Haciendas), a single line of rooms was built around the courtyard connected through a corridor, which allowed crossed ventilation enhancing comfort during the humid season. In the dryer region like the case of Garcia, a fountain was generally placed in the courtyard to add humidity to the microclimate, creating a similar effect through crossed ventilation (Rajapaksha & Rajapaksha, 2008). When the typologies started to change according to the growth of the Metropolitan Area (Spanish cities, suburbs, gated communities, and detached), the courtyards were incorporated in different ways. Figure 45 shows an example of a typical courtyard house, where many of the previously mentioned passive design strategies were used.

According to the predicted mean vote (PMV), if the previously mentioned design strate-

gies were followed, the indoor conditions would still be uncomfortable for 32% of the time during the cold period (Nov-Mar), and for 65% during the hot period (Apr-Oct); see (Milne, 2018). In winter this 32% corresponds to sleep time, so thermal comfort is usually achieved by adding

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clothes and bedding. In summer, however, it is more difficult to cool down the house and the body; therefore mechanical cooling systems are needed. This does not mean that 65% of the time the air conditioning has to be turned on, but it can be used for a short period to regulate the indoor temperature and humidity. Nevertheless, in the case of the MMA, mechanical cooling systems have replaced many times the use of passive strategies, minimizing the adaptation to the climate. The problem is also that these systems require a significant part of the energy that buildings consume (Howe, Gerrard, Fucci, & Association, 2010). That is of course in the case where such systems are affordable; however, in the MMA only 39.8% of the houses have a mechanical cooling system (INEGI, 2015). Thus, the adaptation to climate, regardless of the use of mechanical systems, should play an essential role in the building traditions in the region.

3.2.2 CONSTRUCTION, MATERIALS AND TECHNOLOGY

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A determining factor that has shaped the building traditions in the MMA is the availa-

bility of building materials and the role that the construction industry has played in that matter. Since the pre-colonial era, local materials have constituted the primary source for constructions in the region. However, their extraction, production, end use, and application have presented several transformations. Wood, for example, was the first material used by the nomadic tribes from the region. However, since the colonial period, it has only played a secondary role in the construction sector. Limestone has been by far the raw material that has been used the most in the housing sector in the MMA, mainly in the form of aggregates. Limestone is also used for the production of glass, another industry established in the region after industrialization. Finally, steel is another material that was extensively produced in the region, and that was an important part of the industrial and economic growth of the MMA in the 20th century. Even though most of the raw materials come from local sources, their production process and application have generated several problems in the region concerning pollution, energy use and the adaptability to the climate.

Fig. 48

Typical floorplan of a courtyard house in the MMA. Made by author

Thick walls high thermal mass

Loggia sun control

Fountain evaporative cooling

One row crossed ventilation

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Orientation south-north

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Building a sense of community | The Influence of the Vernacular

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Vegetation Agriculture

Irrigation Seasonal Cattle Pasture Forest Pine Ayarin

Pine - Oak Oak - Pine Oak Shrubbery Submontane Desertic Rosetofilo Thorny Sarco Crasicaule Secondary vegetation Arboreal Shrubby Herbal Physiognomy Subinerme ^^ ^^ ^^

Izotal

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NATURAL RESOURCES, BUILDING MATERIALS AND TECHNIQUES

The geographical position of the MMA, in a transition region between climates, and its

geological history, has generated a very diverse availability of natural resources. Most parts of the subsoil and superficial soils from the region were mainly formed during the Cretaceous Era when the territory was still covered by oceans, which produced sedimentations that led to the formation of limestone and shale. Later during the Palaeocene period, movements in the earth led to the lifting of the sediments, creating the four mountain ranges that surround the metropolitan area: Sierra de la Silla, Sierra Madre Oriental, Sierra de la Mitras, and Sierra el Fraile. The majority of the soils in the valley were then formed during the Quaternary period, by the erosion of the sediments in the mountain ranges that left a layer of sand, clay and lime called alluvium and colluvium (BarbarĂn Castillo, 1995). The organic layer that is the last to form on top is dependant on the presence of water, which together with the temperature also determines the vegetation.

The vegetation then corresponds to three previously mentioned predominant climates.

On the west with a hot arid climate, where Garcia is located, prevails the presence of desert shrubs and with few exceptions, there is almost no agricultural land. In the hot semi-arid climate, which covers most of the MMA, there is a variety of vegetation that corresponds to the height. In the flat regions, hills, and mountain skirts dominate the submontane shrubs with the presence of small trees from species like ebony or mesquite. The high areas, mainly in the Sierra Madre Oriental, located to the south of Monterrey, are covered with forests, mostly from pine and oak. Finally, in the east, where Santiago is located, and that has a humid subtropical climate, there are also different species of shrubs; however, most of the land is covered with agricultural and cattle fields. The urban areas have already anthropogenic soils that have been modified several times, and they are mainly used to host ornamental species (Woerner PetrĂĄn, 1995).

The nomadic tribes that were hunter-gatherers, which lived in the region before the ar-

rival of the Spaniards, used the vegetation that was found in the surface for their constructions. They built very basic dwellings by arranging sticks and tree branches in a conic shape. They organized their temporary dwellings by groups of 15 huts in a row or a semi-circular arrangement

Fig. 49

Vegetation in the MMA. Made by author with information from INEGI (2010)

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Building a sense of community | The Influence of the Vernacular

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Geomorphology Quaternary

Lacustrine Alluvium Colluvium Travertine Terciary Conglomerate Cretaceous

Superior Sandstone - shale Shale - sandstone Limestone - shale Limestone - silstone Inferior Limestone - shale Limestone - dolomite Limestone Limestone - flint Jurasic Shale - sandstone Limestone Gypsum - Limestone

9 8

(Guajardo, 1995). As they never established, they could not develop any further their culture, which was vanished with the arrival of the Spaniards. However, the way of construction did not change considerably for the first decades. The new settlers that included the Spaniards and some Indians also had to build with what was available and without so many economic resources. The building traditions at the beginning were, therefore, a combination of the Spanish knowledge together with the construction workers knowledge, who were mainly native from Tlaxcala, a state located in the centre of the country that had its own pre-colonial culture (Salinas Quiroga, 1981). Wood continued to be used as a primary element for a short period in the region. It then became a secondary element in the construction of roofs until the early 20th century. Then, its structural function was wholly replaced by reinforced concrete and its use until nowadays is focused on the construction of formwork to pour concrete.

According to descriptions from the 17th century (Cavazos Garza, 1995), the majority of the

houses by that time were built with bajaraque, a technique that also used sticks and branches and an additional layer of clay, which served partly as insulation and thermal mass. The structure was made with wood from oak trees. The roofs were covered with reed, which was probably found in the more humid regions from the east. They were pitched because they could not hold any water. The houses from the Spaniards of the high socio-economic classes, which included the governing groups and the owners of the haciendas, were built with adobe. This technique was used in the south of Mexico before their arrival, but that had also been used in Spain for several centuries. They used clay and lime that were taken from the alluvium layer, combined with hay and water, and poured into a wooden form to make bricks, which were used to build the walls. Then, the walls were also covered with a lime mortar. The roofs were built with wooden trunks placed horizontally supported by the walls. They could be almost flat because they were built with a secondary layer of wooden planks and on top another layer of clay and lime-stone aggregates. The doors and windows were made with mesquite wood. This type of construction was ideal against the extreme variations of temperature because it constituted a considerable layer of insulation and thermal mass. In addition, some of them were built with the traditional courtyard typology, which added a cooling passive strategy.

Fig. 50

At the beginning of the 18th century, limestone started to be used in the form of big blocks

Geomorphology in the MMA. Made by author with information from INEGI (2010)

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that were called sillar, which was possible because a quarry was installed on a small hill located to the south of the city called Loma Larga (Martinez, 1997). The blocks even though they were not as compact as adobe, they still represented a suitable material for thermal insulation and mass, apart from having larger durability. Lime mortar was used to fix the blocks together and as a finishing for the interior and exterior of the walls. Natural pigments were added, giving a colourful image to the city. Together with the economic growth of the MMA in the 18th and 19th century, sillar became the most popular material to build in the region. According to Canales (2006), in the 1900 census, there were 6,542 houses in Monterrey, and among them, 197 had two floors, 16 had three, and 1 had four. Canales also writes that in the same year, a local newspaper reported that almost all of the houses were built with sillar, they had colourful faรงades and they were adorned with marble and luxury stones. It pointed out that the demand of sillar was so high that it had doubled the price from 6 years before.

During the 19th century, burned bricks made from clay were also used for the construction

of walls but in fewer quantities; however, by the end of the century, the technique started to get popularity as a response to the high demand of sillar. The first brick industry, Ladrillera Monterrey,

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was founded in 1890. It was promoted and pushed for-ward by investors from the United States, who saw Monterrey as an ideal production and distribution centre for the region (Leal Martinez, 1986). The clay that was taken from the valley was also burned to produce floor and roof tiles. The use of the latter was not so usual in the MMA as most of the roofs were flat. Nevertheless, in the 20th century, they found a significant market in other parts of the country, where the Roman-Arabic tradition, which as brought by the Spaniards, was more common. Lately, with the North American influence, burned brick is used as a veneer or finishing for the faรงades, adding some insulation and thermal mass to the house. The use of brick soon replaced the predominance of the sillar and the adobe in the region; however, concrete, a new material that appeared with industrialization, rapidly took over the construction market that grew exponentially since the 1940s. This growth was led by CEMEX, a company that was founded in 1906.

Concrete is created with a mixture of gravel, sand, cement, and water. In the MMA the first

three elements come from limestone. Gravel and sand are obtained by crushing and pulverizing

tion, which as brought by the Spaniards, was more common. Lately, with the North American influence, burned brick is used as a veneer or finishing for the facades, adding some insulation and thermal mass to the house. The use of brick soon replaced the predominance of the sillar and the adobe in the region; however, concrete, a new material that appeared with industrialization, rapidly took market that grew the stone, and cement is produced by elevating it to over very the highconstruction temperatures. The mineral that exponentially since the 1940s. This growth was led by CEMEX, a company that was is found extensively in the subsoils of the region represented the base for the modernization of founded in 1906. settlements. In the MMA it was mainly extracted from the Sierra de las Mitras and Cerro del Topo Concrete when is created with sprawl a mixture of gravel, sand, cement, and water. MMA Chico. However, the urban reached those regions, the quarries becameIna the danger and the first three elements come from limestone. Gravel and sand are obtained by crushing a high source of pollutants, so they had to be relocated to San Miguel and the Huasteca (Guerra and pulverizing the stone, and cement is produced by elevating it to very high temperaGarcía, The latter recently closed in 2015 to the of same (Muñiz & García, tures.1999). The mineral thatwas is found extensively in thedue subsoils the reasons region represented the base Cement, for the modernization of as settlements. the MMA itchapter, was mainly extracted from 2015). in all of its forms, explained inInthe previous gave the possibility to the have Sierra de las Mitras and Cerro del Topo Chico. However, when the urban sprawl reached an easy-to-build frame construction, which was established as the primary building technique of those regions, the quarries became a danger and a high source of pollutants, so they had the Even though can be considered a local material, energy for The transportation, tocountry. be relocated to SanitMiguel and the Huasteca (Guerrasaving García, 1999). latter wasit recently closed in 2015 duefor toits the same reasons (Muñiz & García, 2015). in all needs a considerable amount production, contributing significantly to theCement, CO2 emissions. of its forms, as explained in the previous chapter, gave the possibility to have an easy-toThe main form of concrete for the construction of walls is the hollow block, a material that is not build frame construction, which was established as the primary building technique of the entirely adequate for the region because of its low thermal insulation and thermal mass in comparcountry. Even though it can be considered a local material, saving energy for transportaison to other materials that have been usedfor throughout historycontributing in the region.significantly Table 4 showstotypical tion, it needs a considerable amount its production, the

CO2 for emissions. Themost mainused form of concrete for the construction of walls isisdependant the hollowon values some of the materials in construction. Thermal insulation block, a material that is not entirely adequate for the region because of its low thermal the thickness and the thermal conductivity, while thermal mass is dependant on the thickness, the insulation and thermal mass in comparison to other materials that have been used density and thehistory heat capacity of the materials. throughout in the region. Table X shows typical values for some of the most used materials in construction. Thermal insulation is dependant on the thickness and the thermal conductivity, while thermal mass is dependant on the thickness, the density and the heat capacity of the materials. Material Air at 20°C

Thickness

Thermal Conductivity

Density

Heat Capacity

(m)

k = (W/ m ºC)

(kg/m )

J/kgºC

0.03

1.20

1,000

240

1,420

Thatched roof

0.05

0.07

Pinewood

0.12

0.13

610

1,420

0.4

0.58

1,698

1,000

Adobe Compressed earth block

0.15

0.66

2,050

1,000

Massive concrete block

0.12

0.91

1,400

1,000

Burned brick

0.12

0.96

1,800

800

Glass

0.03

1.10

2,500

840

Concrete hollow block

0.15

1.20

1,700

840

Reinforced concrete

0.1

1.40

2,100

840

Sillar

0.4

1.40

2,180

1,000

0.02

50.00

7,800

480

Metallic sheet

(Fuentes Freixanet, 2000; Roux Gutierrez, Velazquez Lozano, & Rodriguez Deytz, 2015)

Table 4 Thermal conductivity and mass of common building materials. Made by author with information from Fuentes Freixanet (2000) and Roux Gutierrez, Velazquez Lozano 67 & Rodriguez Deytz (2015)

139

The use of limestone in the MMA was also dedicated to the production of flat glass for

its use in windows. Another material that drastically increased its use after industrialization and that has been widely used in the MMA. Glass is generally produced by melting silica sand, sodium carbonate and limestone. The central element used for its industrial production, silica sand, was obtained from Coahuila, the neighbouring state. These conditions made it possible for the first glass industry, Vidriería Monterrey (today Vitro), to establish in the country, whose focus was first, the production of bottles, and by the middle of the 20th century, also the construction sector (Salomón, 2003). The influence of glass in the housing typologies from the MMA has gradually modified the façades and sometimes even the form and orientation of the constructions. However, due to its high costs this influence can be perceived more within the high socio-economic classes. Only a small part of the population can afford the predominance of glass façades in search of transparency and views. The sense of security and the climate are other factors that probably have prevailed as determining aspects in the construction of dwellings, reflected in the relation between openings and walls. Arguably, in general, façades from single-family houses in the MMA have a small proportion of openings, and if they are open, they face a private garden or courtyard.

3. Case Studies | The Influence of the Vernacular

140

The soils of Nuevo Leon and a large part of the Northeast of Mexico also have a rich me-

tallic mineral content, which made it also possible for the mining industry to flourish in the region (Rojas Sandoval, 1998). Iron, which was found over the region, was the first metal to be used in the housing constructions in the MMA in the 18th century for the production of burglar bars and railings. As already explained, they were used for protection and had influence from the Spanish tradition. In the 19th century industrialization made possible the alloy of iron and carbon (also found in the region) to produce steel, which added malleability, elasticity, and resistance to the previously used technique. From the 20th century steel became a primordial material for the construction sector. The main industry, Fundidora de Fierro y Acero de Monterrey, was founded in 1900, which acted as a pillar of economic growth of the city. Since then, steel has represented a vital part of the market in the building industry (Campos Serna, 1992); yet, in the housing sector, it has mainly been used only as reinforcement for concrete structures in the form of rebars. Meanwhile, Iron kept the same protective function, and it is still used nowadays.

MATERIAL INDUSTRY AND MARKET IN THE 21ST CENTURY

The material industry has significantly driven the construction market in Mexico, but in

the MMA, which has been a centre of modernization, it is more clearly perceived. Since the 20th century, end products like adobe, sillar, and cut wood, which were extensively used in the region before industrialization, are in general not well accepted among the occupants, builders, and construction workers. Few companies, who knew how to take advantage of the regional natural resources, the low prices of energy sources and labour, and the fast growth of cities, have absorbed the market. These companies are focused mainly on cement, steel and glass products. As previously mentioned, their marketing campaigns, as in the case of cement, also contributed to their constant inclusion to the market and to create a consolidated building tradition.

According to the National Census (INEGI, 2015), by 2015 there were 1,200,907 in-habited

dwellings in the MMA. From that total 97.3% used brick or concrete block as the primary material for the construction of walls, 1.8% used adobe and wood, and only 0.2% used bajareque or reed. Even though the difference between brick and concrete blocks is not specified, there have been reports that confirm the predominance of concrete in the construction sector (Campos Serna, 1992; Guerra GarcĂa, 1999). For the roof construction 92% used reinforced concrete, 7% used metallic or asbestos sheet, and only 0.1% used wood and compacted earth. Finally, for the floor, 98.6% were built with concrete, from which 39.6% was left exposed, and 58.9% had tiles or wooden flooring; the other 0.8% had compacted earth floor. These numbers, together with the existing reports can give us a clear idea of the market in the MMA.

The local industries that lead the construction material market processing can be observed

in figure 48. Many of them are still the pioneer industries within their sectors, which is the case of CEMEX with cement products and concrete, Vitro with glass and Lamosa with flooring and tiles. There are also other industries that incorporated later but that have taken over the market, which is the case of Ladrillera Mecanizada, with brick products and Ternium with steel production. The map also shows the extraction points within the region. Sand and gravel, mainly from limestone, have been the most extracted materials essentially for their use in the cement and concrete indus-

141

calcite

CEMEX

gypsum phosphorite

HIDALGO

limestone

limestone aggregates

gypsum

SIERRA EL FRAILE Y SAN MIGUEL

gypsum

limestone aggregates

shale aggregates

lime adobe

LADRILLERA MECANIZADA

LADRILLERA STA. CLARA

CERRO DEL TOPO CHICO VITRO CALIDER

SOLVAY

marble

EL ALCALI

limestone aggregates

INDUSTRIALIZADORA DE CALIZA

limestone aggregates

SIE

RRA L

TERNIUM

AS M

ITR AS

limestone aggregates

VITRO

limestone

limestone aggregates

LA HUASTECA

CEMEX LAMOSA

CEMEX

shale aggregates

142 Building a sense of community | The Influence of the Vernacular

TERNIUM

Pb, Zn

Material Industry Rocks aggregates bank Productive Inactive Mines Productive Inactive Industry Non-metal processing Metal casting

marble

MINERA DEL NORESTE

try. Although it has traditionally been a local product, the regional shortage and the prohibition of extraction have turned it into an essential source of imports and exports, which has increased its value almost six times in 25 years. Massive extraction has physically altered rivers and mountains, has increased the number of sediments in the air and has caused erosion (Torres, 2017).

These problems, together with the high amount of energy use and CO2 emission in the

production of concrete, have urged the search on new solutions. However, it is not easy to modify an established market. According to Felix Guerra, the owner of the only compressed earth blocks (CEB) industry in the MMA, there have been several obstacles that have hampered their attempts to enter into the housing market. His company called Arqime, located in Garcia produces blocks by compressing clay and aggregates, taken from the alluvium layer, and lime with high hydraulic pressure. This process generates a material with very low embodied energy, high insulation properties and very high thermal mass, which is adequate for the climate in the region. Because of its high compression, it is much more durable than adobe, yet, their resemblance is very similar. Thus, its social acceptance has been very low because people relate it with adobe, a material associated with low socio-economic classes and going against the idea of progress. Another obstacle reported by Felix Guerra is its acceptance among construction workers. As it is a material with a considerable amount of mass that makes it very heavy, it is more difficult to carry it, so there have been regular complaints within the construction sites where it has been used. The last obstacle reported is the price, because it has been challenging to compete with the prices of the big and already long-established industries (F. Guerra, personal communication, August 2, 2018).

Wood is another material that has been tried to enter the housing market without success.

According to Gonzalo Chapela (2012), wooden construction are hardly appreciated in the real estate market, mainly by a perception of perishability and precariousness. This rejection can be seen, for example, in the restrictions imposed by financial institutions to give mortgages for houses that have been built with wood. However, there is a great potential in the use mainly of pinewood for the construction sector in Mexico, for example in the production of beams, as it has been done in many other countries. Nowadays the main niche of pinewood in the country is the production of formwork, secondarily the production of doors and windows, and thirdly the flooring. Another important niche is the production of furniture. In Nuevo Leon, they are typically fabricated

Fig. 51

Material extraction and industry over geomorphology map in the MMA. Made by author with information

from INEGI (2010)

10 km

143

Building a sense of community | The Influence of the Vernacular

144

with oak, ebony, and mesquite, however, a significant part of the extraction is done illegally, and reforestation is not a common practice. The mountain range located to the south of the MMA is covered with forests that could be used for construction; nevertheless, this resource is not sustainably exploited. Otherwise, it could represent a very feasible alternative to the frame reinforced concrete construction that is the basis of the current building traditions in the country. It could be a renewable solution that requires just a fraction of the embodied energy, and that existed in the region since the foundation of the city.

145

Fig. 52

Satellite image of the MMA (Google, 2019)

10 km

Building a sense of community | The Influence of the Vernacular

146

3.2.3 GARCIA

Garcia has a relatively long history, which developed parallel to the city of Monterrey

along with the Spanish domination. It was founded in the 16th century as a cross-roads village. In the following centuries the population expanded because two haciendas were established; however, the economy (based on agriculture and cattle) and urban growth remained relatively low until the 20th century (J. G. Garza, 2018). It was then when this municipality took part in the industrial expansion of the region and started to serve as a satellite town to the urban sprawl from the other municipalities. Its extension followed similar patterns to the ones described by Griffin and Ford (1980). It maintained one CBD inhabited mainly by the elite groups, descendants of Spanish families, where courtyard typologies were developed and are still present until today. The peripheries started to be filled with suburbs typologies that increased with the financing programmes offered by INFONAVIT and the government. More recently the urban sprawl continued to be filled with gated communities with social housing that were developed by companies that targeted the industry workers. Further away there are also rural detached typologies, which were also part of this study.

This municipality is located on the aridest region of the MMA. It stands in between two

climates, the hot desert (BWh) and the hot steppe (BSh). The three selected houses, which can be seen in figure 50, where the measurements and interviews were carried out, are located within the hot desert climate (BWh). The first two houses have an evident influence of the vernacular. They were both built with adobe, and have several features that respond to the socio-cultural history of the city, the site and the climate in which they were built. They had, therefore, a better thermal performance than the third example. The first house that corresponds to the residential plus segmentation is located in the CBD, characterized by its artificially maintained vegetation, which resembles an oasis in the satellite image. The second house, from a lower socio-economic segmentation, is located in the rural region of the municipality. The third house that can be classified as a conventional house is one of the repeated typologies that were developed as part of the suburbs, which are depicted by the grey landscape in the satellite image.

Fig. 53

Satellite image of Garcia, NL (Google, 2019)

147

HOUSE 1

Segmentation

3. Case Studies | The Influence of the Vernacular

148

Builder Year of construction

Residential-plus Architect / Owner 2006

Construction area

314.4 m2

Loggia/terrace area

315.2 m2

Garden/open area

355.7 m2

Inhabitants

3 (104.8 m2 / person)

Exterior walls

Adobe (60 cm)

Interior walls

Adobe (60 cm)

GSPublisherVersion 0.0.100.100

Plaster Walls structure Roof Interior floor Exterior flooring Windows

Gypsum based mortar Burned brick Pinewood beams, Pinewood planks (3 cm), reinforced concrete (10 cm) Polished cement screed (8 cm) Shale Pinewood doors, no glazing

Fig. 54

Axonometric view of house 1. Made by author

Fig. 55

Ground floor plan of house 1. Made by author

Fig. 56

Transversal section of house 1. Made by author

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150

Fig. 57

Exterior facade of house 1. Taken by author

Fig. 58

Courtyard loggia of house 1. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (living room) 28.9 °C Temperature

Temperature 33.4 °C

34.2 % Relative humidity

Relative humidity 34.1 %

19.5 °C Dew point

Dew point 15.5 °C Illuminance 1600 lux

45 lux Illuminance

Wind speed 0.62 m/s

0.26 m/s Wind speed

Wall outer surface temperature 42 °C

31 °C Wall inner surface temperature

Roof outer surface temperature -

37 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The house stands where an old casona used to be. The ruins of the old house inspired

the owner, who tried to translate the vernacular style into a contemporary construction. All the building materials were taken from the region and adapted according to comfort and structural needs. The windows, doors, and most of the furniture pieces are reused. The thick adobe walls with a relatively small proportion of openings give considerable thermal mass to the construction, which contributes, together with the high ceilings, to having a temperature difference of 4.5 °C between the interior and exterior. The density is also reflected on the surface temperature of the facade wall, which had a difference of 11 °C between interior and exterior. The space of the house, which the interviewee uses the most is the living room, where the measurements were taken, and the loggia. The user sometimes prefers the latter because it is brighter and it feels fresher, which was attributed to the wind and the general natural ambience of the courtyard (J. Garcia, personal communication, August 8, 2018).

151

HOUSE 2

Segmentation

3. Case Studies | The Influence of the Vernacular

152

Builder Year of construction

Traditional Self-built 2000

Construction area

70.5 m2

Loggia/terrace area

32.4 m2

Garden/open area Inhabitants

aprox. 3000 m2 8 (8.8 m2 / person)

Exterior walls

Compressed earth blocks (20 cm)

Interior walls

Compressed earth blocks (15 cm)

GSPublisherVersion 0.0.100.100

Plaster Walls structure Roof

None Reinforced concrete frame construction Reinforced concrete beam and EPS system (18 cm), partly with clay tiles

Interior floor

Cement screed (7 cm), ceramic tiles

Exterior flooring

Cement screed (7 cm), ceramic tiles

Windows

Aluminum frame, single glazed

Fig. 59

Axonometric view of house 2. Made by author

Fig. 60

Ground floor plan of house 2. Made by author

Fig. 61

Transversal section of house 2. Made by author

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154

Fig. 62

Exterior facade of house 1. Taken by author

Fig. 63

Courtyard loggia of house 1. Taken by author

COMFORT MEASUREMENTS

Exterior average values (Loggia)

Interior average values (living room) 31.2 °C Temperature

Temperature 33.6 °C

35.5 % Relative humidity

Relative humidity 35.4 %

18.3 °C Dew point

Dew point 14.2 °C

70 lux Illuminance

Illuminance 1650 lux Wind speed 0.6 m/s

0.22 m/s Wind speed

Wall outer surface temperature 37 °C

30 °C Wall inner surface temperature

Roof outer surface temperature 47 °C

38°C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The house is built with compressed earth blocks (CEB) that were produced on site, with

raw materials also extracted from the site. They have a considerable high density that enhances the delay of temperature transmission between outside and inside, which is perceived on the wall surface temperature difference of 7 °C. However, the inhabitants normally leave the doors and windows open to allow ventilation, and this is why the inner and outer values are similar. The CEBs are used as a replacement of adobe blocks, which was a local building technique that required more maintenance and had less durability. Apart from the use of local materials, the house has also an aesthetic influence from the colonial style, characterized mainly by the loggia, the burglar bars, the clay tiles, and the distribution of the space. Nevertheless, the house is relatively small in comparison to the Spanish typologies. The overcrowding of the space reflects the low socio-economic position of the inhabitants, who prefer to stay outside or in the loggia most of the time during the day to avoid overheating and discomfort (F. Guerra, personal communication, August 2, 2018).

155

HOUSE 3

Segmentation

3. Case Studies | The Influence of the Vernacular

156

Builder Year of construction

Popular Developer / self-built 2000

Construction area

50.5 m2

Loggia/terrace area

9.6 m2

Garden/open area Inhabitants

38.0 m2 2 (25.3 m2 / person)

Exterior walls

Concrete hollow blocks (15 cm)

Interior walls

Concrete hollow blocks (15 cm)

GSPublisherVersion 0.0.100.100

Plaster/finishing Walls structure Roof Interior floor Exterior flooring Windows

Cement based mortar/vinyl paint Reinforced concrete frame construction Reinforced concrete (12 cm) Cement screed (7 cm), ceramic tiles Concrete pavement Aluminum frame, single glazed

Fig. 64

Axonometric view of house 3. Made by author

Fig. 65

Ground floor plan of house 3. Made by author

Fig. 66

Transversal section of house 3. Made by author

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158

Fig. 67

Exterior facade of house 3. Taken by author

Fig. 68

Kitchen/entrance of house 3. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (living room) 32.0 °C Temperature

Temperature 33.1 °C

33.1 % Relative humidity

Relative humidity 35.7 %

14.1 °C Dew point

Dew point 13.9 °C Illuminance 1260 lux

40 lux Illuminance

Wind speed 1.85 m/s

0.25 m/s Wind speed

Wall outer surface temperature 37 °C

35 °C Wall inner surface temperature

Roof outer surface temperature -

38 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The house was built as part of a ‘progressive’ housing system launched by INFONAVIT, in

which basic housing units were built repeatedly one after the other, with the idea of a future extension by the owners. The house was then a result of the mass production process that took place in the region at the end of the 20th century. The building materials and technique were based on the cement ready-to-build model which was described in the previous chapter. The inhabitants extended years later part of the kitchen, a bathroom, and changed partly the facade, which added certain identity to the house. Nevertheless, as described by one of the users, the house is very hot; one of the reason why the overall satisfaction of the user was relatively low. (H. Lomas, personal communication, August 3, 2018). A possible explanation is the small difference between interior and exterior temperature and humidity values. In contrast with the other two typologies, the ceilings are very low, and the surface temperature of the walls is very similar on the interior and exterior, which reflects the low thermal mass and conductivity of the hollow concrete blocks.

159

Building a sense of community | The Influence of the Vernacular

160

3.2.4 MONTERREY

Monterrey is the capital of the State of Nuevo Leon, and therefore it centralizes most

part of the political and economic power. It is also the oldest settlement of the region, where the town of Santa Lucia was established in 1577, and some years later the Spanish city of Monterrey. The first settlement was located close to the river Santa Catarina, where the symbol that shows typology number 5 is positioned over the satellite image (figure 66). The city then started to grow exponentially towards the peripheries, hand by hand with industrialization and modernity, as explained in the previous sections. At the end of the 20th century, it also started to extend along the valley to the south, where examples 4 and 6 are located, until reaching the municipality of Santiago. In every other direction, it also expanded â&#x20AC;&#x153;absorbingâ&#x20AC;? the neighbouring municipality, creating a relatively large Metropolitan area. It is also, therefore, one of the densest municipalities. Apart from the mountain ranges, it was left without almost no space to build, which has lately urged for solutions to densify it vertically to meet the needs of the still growing population. 161

This municipality has a hot steppe (BSh) climate. It is located within a transition region

between an arid and a subtropical climate and therefore has characteristics from both of them. The comfort measurements and interviews were performed during one of the warmest periods of the year, but also one with the most precipitation, which was reflected on the relatively high humidity that is shown in the results. The fourth and fifth studied typologies have a more direct influence of the vernacular, which can be found in the building materials, their form, and relation to the context. The fourth house, which corresponds to a high socio-economic segmentation, is located within a gated community, and it is an example of vernacular principles that are applied together with contemporary technologies (high-tech). The fifth house, from a lower socio-economic segmentation, is located in the historic district or CBD. It is one of the few examples in the city where sillar, the big limestone blocks, were still used for the construction. The sixth case is a typical example of a mass production typology, built by developers within a gated community targeting a high socio-economic group, and therefore defined in this study as a conventional typology.

Fig. 69

Satellite image of Monterrey, NL (Google, 2019)

HOUSE 4

Segmentation

3. Case Studies | The Influence of the Vernacular

162

Builder Year of construction

Residential-plus Architect / Owner 2014

Construction area

213.4 m2

Loggia/terrace area

115.8 m2

Garden/open area

385.6 m2

Inhabitants

3 (71.1 m2 / person)

Exterior walls

Cavity wall with massive concrete blocks (40 cm)

Interior walls

Concrete hollow blocks (15 cm)

GSPublisherVersion 0.0.100.100

Plaster Walls structure Roof Interior floor Exterior flooring Windows

Cement based mortar Reinforced concrete frame construction Pinewood beams, Pinewood planks (3 cm), r. concrete (10 cm), EPS (5 cm) Cement screed (7 cm), marble plates Cement screed (7 cm), ceramic plates PVC frame, double glazed

Fig. 70

Axonometric view of house 4. Made by author

Fig. 71

Ground floor plan of house 4. Made by author

Fig. 72

Transversal section of house 4. Made by author

N 1:200

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164

Fig. 73

Courtyard facade of house 4. Taken by author

Fig. 74

Dinning room/kitchen of house 4. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (living room) 31.4 °C Temperature

Temperature 35.3 °C

44.8 % Relative humidity

Relative humidity 40.4 %

19.0 °C Dew point

Dew point 20.7 °C Illuminance 1600 lux

380 lux Illuminance

Wind speed 0.45 m/s

0.2 m/s Wind speed

Wall outer surface temperature 37 °C

32 °C Wall inner surface temperature

Roof outer surface temperature -

33 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house is built as a typical courtyard typology, with the reference of a Spanish haci-

enda. Its design includes passive principles, as the use of the shaded courtyard with the pool for passive evaporative cooling. It has also an ideal orientation and uses a series of overhangs to avoid solar gains. The walls are built with a double layer of massive material separated by an air gap, which adds a considerable amount of thermal mass and insulation to the construction. However, in contrast with traditional typologies, it has big openings, which is possible because the doubled glazed windows have relatively good thermal values in comparison to conventional glazing. Another difference is the airtightness of the envelope, which allows more controlled management of the indoor temperature. This is how the users can optimize the use of the air conditioning system, which according to one of the users it is only turned on during short periods during the day (D. Gonzalez, personal communication, August 17, 2018). Nevertheless, the measurements were taken with open windows, which explains the relatively high indoor temperature values registered.

165

HOUSE 5

Segmentation

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166

Builder Year of construction Construction area Loggia/terrace area Garden/open area Inhabitants

Traditional Self-built 1956 - renovated 2000 90.0 m2 53.0 m2 2 (45.0 m2 / person)

Exterior walls

Sillar (60 cm)

Interior walls

Sillar (60 cm)

GSPublisherVersion 0.0.100.100

Plaster

Walls structure Roof Interior floor Exterior flooring Windows

Gypsum based mortar Sillar Reinforced concrete (12 cm) Rammed earth (20 cm), clay tiles clay tiles Iron frame, single glazed

Fig. 75

Axonometric view of house 5. Made by author

Fig. 76

Upper floor plan of house 5. Made by author

Fig. 77

Ground floor plan of house 5. Made by author

Fig. 78

Transversal section of house 5. Made by author

N R

GSPublisherVersion 0.0.100.100

1:200

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168

Fig. 79

Exterior facade of house 5. Taken by author

Fig. 80

Living room of house 5. Taken by author

COMFORT MEASUREMENTS

Exterior average values (Street)

Interior average values (living room) 29.4 °C Temperature

Temperature 32.4 °C

45.2 % Relative humidity

Relative humidity 43.6 %

16.2 °C Dew point

Dew point 17.4 °C Illuminance 1650 lux

300 lux Illuminance

Wind speed 0.42 m/s

0.35 m/s Wind speed

Wall outer surface temperature 42 °C

33 °C Wall inner surface temperature

Roof outer surface temperature -

37 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house is located within the dense urban grid of the Barrio Antiguo (spanish for old

neighbourhood), where the Spanish elite once settled, but that was replaced by low socio-economic groups after the elite migrated to the peripheries. The main elements where the influence of the vernacular is evident is the use of sillar as the main material for the wall construction and the use of the patio to enhance natural ventilation. The high thermal mass of the envelope is reflected on the relatively high temperature difference (9 °C) between the inner and outer wall surface. On the opposite, even though the wind speed was relatively low, it was maintained similar on the outside and the inside. That was possible due to the large openings and the distribution of the space in one row, which allows crossed ventilation. As explained by the owner, the air circulation considerably improves the thermal sensation, which can be very hot during some periods of the day. He also assured that the material responded always adequately to external conditions that can also be cold during winter (G. Tovar, personal communication, August 26, 2018).

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HOUSE 6

Segmentation

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170

Builder Year of construction

Residential-plus Developer 2010

Construction area

228.7 m2

Loggia/terrace area

46.2 m2

Garden/open area

47.5 m2

Inhabitants

3 (76.2 m2 / person)

Exterior walls

Concrete hollow blocks (15 cm), partly limestone veneer (2 cm)

Interior walls

Concrete hollow blocks (15 cm)

Plaster/finishing

GSPublisherVersion 0.0.100.100

Walls structure Roof

Cement based mortar/vinyl paint Reinforced concrete frame construction Reinforced concrete (12 cm)

Interior floor

Cement screed (7 cm), ceramic tiles

Exterior flooring

Cement screed (7 cm), ceramic tiles

Windows

Aluminum frame, single glazed

Fig. 81

Axonometric view of house 6. Made by author

Fig. 82

Upper floor plan of house 6. Made by author

Fig. 83

Ground floor plan of house 6. Made by author

Fig. 84

Transversal section of house 6. Made by author

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172

Fig. 85

Exterior facade of house 6. Taken by author

Fig. 86

Dinning room of house 6. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (dinning room) 31.5 °C Temperature

Temperature 32.2 °C

42.6 % Relative humidity

Relative humidity 42.4 %

14.8 °C Dew point

Dew point 15.4 °C Illuminance 1470 lux

150 lux Illuminance

Wind speed 0.35 m/s

0.12 m/s Wind speed

Wall outer surface temperature 42 °C

36 °C Wall inner surface temperature

Roof outer surface temperature -

38 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The house is part of a horizontal condominium or gated community that has 200 repeated

residential-plus units. They are built with the conventional building concrete-based technique that is used for most of the constructions in the MMA. The design and distribution respond to a typical suburbs market looking, as previously mentioned, for a lifestyle similar to the ‘American dream’. However, it has also some characteristics that show an intention to adapt to a local identity, for example, the use of limestone as part of the aesthetics of the facade. Still, the adaptation to the climate is hardly perceived. The low thermal mass and insulation of the envelope cause the conditions on the outside and inside to be very similar. The general distribution of the floor plan, the orientation of the house, and the openings do not enhance natural ventilation, which was very poor, as reflected on the measured values. Those conditions produce discomfort on the occupants, who prefer to use the air conditioning during most of the day (L. Moyar, personal communication, August 26, 2018).

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Building a sense of community | The Influence of the Vernacular

174

3.2.5 SANTIAGO

Santiago is part of the MMA since 2010, so it was one of the last to be incorporated into the

Metropolitan area. Its history also started as an hacienda that belonged to one of the families that founded the city of Monterrey. It slowly developed into a colonial town with a relatively small population. In contrast with every other municipality from the MMA, Santiago has kept a provincial character since then. Given its relatively long distance to the area where most industries flourished during the 20th century, the urban growth remained stable, and instead, the population focused for a long time on a rural economy. Lately, there have also been an efforts to promote tourism, taking advantage of the picturesque town and the rich natural resources. It has also become a weekend destination for many inhabitants of the other municipalities. The water body that can be seen in figure 84 is a dam, part of a system that supplies water to the MMA, which has also become one of the attractions of the floating population. It was also built to control the floodings that affected for centuries the settlements on the valley (Esparza Hernandez, Valdés Lozano, Cantú Martínez, & de la Mora, 2014).

175

Most of the municipality has a humid subtropical climate (Cwa). Even though it is consid-

ered a different climate, the exterior conditions showed similar patterns to the other two climates, as previously expected. The comfort measurements were carried out in three typologies with very different characters. The first one, house number 7, is a rural detached typology located relatively far from the urban settlement. The owners, who followed vernacular principles together with new technologies, have taken advantage entirely of the site resources to create a self-sustainable unit. The next house, number 8, is located in the centre of the old Spanish town, today the CBD. It was first built in the 1940s with sillar, and it was lately completely renovated, but the owners restored the facade, kept a similar configuration and as they declared, the identity of the old house. The last house from this case study is again part of a gated community, where developers built repeated residential-plus typologies targeting the “American dream” market.

Fig. 87

Satellite image of Santiago, NL (Google, 2019)

HOUSE 7

Segmentation

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176

Builder Year of construction

Residential Contractor / Owner 2003

Construction area

150.0 m2

Loggia/terrace area

84.9 m2

Garden/open area Inhabitants

aprox. 8000 m2 2 (75.0 m2 / person)

Exterior walls

Compressed earth blocks (20 cm)

Interior walls

Compressed earth blocks (15 cm)

GSPublisherVersion 0.0.100.100

Plaster Walls structure Roof

None Reinforced concrete frame construction Reinforced concrete beam and EPS system (18 cm), partly with clay tiles

Interior floor

Cement screed (7 cm), ceramic tiles

Exterior flooring

Cement screed (7 cm), ceramic tiles

Windows

PVC frame, double glazed

Fig. 88

Axonometric view of house 7. Made by author

Fig. 89

Ground floor plan of house 7. Made by author

Fig. 90

Transversal section of house 7. Made by author

1:200

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178

Fig. 91

Exterior facade of house 7. Taken by author

Fig. 92

Living room of house 7. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (living room) 29.8 °C Temperature

Temperature 32.3 °C

43.5 % Relative humidity

Relative humidity 45.3 %

13.5 °C Dew point

Dew point 13.8 °C Illuminance 1625 lux

25 lux Illuminance

Wind speed 0.71 m/s

0.6 m/s Wind speed

Wall outer surface temperature 35 °C

30 °C Wall inner surface temperature

Roof outer surface temperature 48 °C

34 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The house is built following different passive and active strategies to work as an off-the-

grid example. That means that the owners generate the energy that they consume, they take the water from a natural source and produce most of the food that they consume. The walls were built with compressed earth blocks, with materials taken from the region. The same for the wood that was used for beams and the furniture. The energy is produced with solar panels and with a water mill that uses the flow of a stream. The water is canalized into a pond with an aquaponic system, where fish, roots and vegetables are produced. The indoor values showed a relatively high temperature during the day. However, the owner stated that with natural ventilation, with the aid of a fan, a comfortable sensation is achieved during the day and even more during the night. This could be attributed to the relatively high humidity values during the summer in this region. In addition, during winter, the heat is easily maintained inside the house, so overall he rated it as very comfortable (J. Villarreal, personal communication, August 7, 2018).

179

HOUSE 8

Segmentation

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180

Builder Year of construction

Traditional Self-built aprox. 1940 - renovated 2007

Construction area

90.0 m2

Loggia/terrace area

34.4 m2

Garden/open area Inhabitants

310.0 m2 4 (22.5 m2 / person)

Exterior walls

Partly Sillar (60 cm), partly clay hollow block (20cm)

Interior walls

Partly Sillar (60 cm), partly clay hollow block (15 cm)

GSPublisherVersion 0.0.100.100

Plaster

Walls structure Roof Interior floor Exterior flooring Windows

Gypsum based mortar Partly Sillar, partly reinforced concrete frame construction Reinforced concrete beam and EPS system (20 cm) Cement screed (7 cm), ceramic tiles Concrete tiles Iron frame, single glazed

Fig. 93

Axonometric view of house 8. Made by author

Fig. 94

Ground floor plan of house 8. Made by author

Fig. 95

Transversal section of house 8. Made by author

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12 :54

1:200

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182

Fig. 96

Exterior facade of house 8. Taken by author

Fig. 97

Interior corridor of house 8. Taken by author

COMFORT MEASUREMENTS

Exterior average values (Street)

Interior average values (living room) 29.6 °C Temperature

Temperature 32.8 °C

45.8 % Relative humidity

Relative humidity 47.9 %

16.6 °C Dew point

Dew point 18.2 °C Illuminance 1400 lux

15 lux Illuminance

Wind speed 0.38 m/s

0.12 m/s Wind speed

Wall outer surface temperature 41 °C

30 °C Wall inner surface temperature

Roof outer surface temperature -

34 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house is located in the centre of Santiago, where most of the houses are built with

the typical colonial style of the region. Even though it is a renovation, it constitutes an important example of how can pre-industrial building techniques have been maintained until today. According to the owner, sillar cannot be obtained anymore in the region, and that is why they chose a different solution during the renovation. Nevertheless, the facade where the massive stone was used, showed relatively good values for heat transmittance, with a difference of 11 °C between the inner and outer surface. Nevertheless, the compact form and the spatial configuration did not allow proper natural ventilation, which together with the high indoor temperature and the low illuminance, generated sometimes discomfort for the inhabitants during the day. Still, the overall satisfaction of the interviewee was regarded as comfortable throughout the year (L. Lopez, personal communication, August 23, 2018).

183

HOUSE 9

Segmentation

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184

Builder Year of construction

Residential-plus Developer 2010

Construction area

298.7 m2

Loggia/terrace area

69.4 m2

Garden/open area

85.9 m2

Inhabitants

4 (74.7 m2 / person)

Exterior walls

Concrete hollow block (15 cm)

Interior walls

Concrete hollow block (15 cm)

Plaster/finishing

Cement based mortar

GSPublisherVersion 0.0.100.100

Walls structure Roof Interior floor Exterior flooring Windows

Reinforced concrete frame construction Reinforced concrete beam and EPS system (20 cm) Cement screed (7 cm), partly ceramic tiles, partly laminated Partly ceramic tiles, partly asphalt Aluminium, single glazed

Fig. 98

Axonometric view of house 9. Made by author

Fig. 99

Upper floor plan of house 9. Made by author

Fig. 100 Ground floor plan of house 9. Made by author Fig. 101 Transversal section of house 9. Made by author

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1:200

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186

Fig. 102 Exterior facade of house 9. Taken by author Fig. 103 Dinning room of house 9. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (dinning room) 32.2 °C Temperature

Temperature 32.3 °C

52.4 % Relative humidity

Relative humidity 54.5 %

29.5 °C Dew point

Dew point 20.2 °C Illuminance 1510 lux

55 lux Illuminance

Wind speed 0.78 m/s

0.08 m/s Wind speed

Wall outer surface temperature 39 °C

32 °C Wall inner surface temperature

Roof outer surface temperature 44 °C

38 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house is a typical example in which the developers sought to give a vernacular ap-

pearance to the facade, but it is built as a conventional cement-based construction. The measurements were taken when the air conditioner was turned off, and some of the windows were open. That could explain the similar values between outside and inside. However, as noted by one of the users, the overheating of the house is common when the AC is off, and the humidity can get very high. That is why they usually use it during day and night. The wind speed was relatively low on the inside, which can be explained by the configuration of the space and the orientation, another reason of discomfort as regarded by the interviewee (J. Moreno, personal communication, August 24, 2018). Regardless this situation, the overall comfort was rated above neutral, which was also attributed to other factors related to the quality of life of the city and to the neighbourhood, which will be reviewed on the results chapter.

187

3.3

CASE STUDY 2 TROPICAL CLIMATE: ISTMO DE TEHUANTEPEC, OAXACA

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188

Some of the most ancient civilizations in Mexico established in the region called Istmo de Te-

huantepec (IT). In contrast with the north of the country, it has a very long pre-industrial history. The influence of the indigenous cultures is still present in many aspects of the society including its building traditions and rituals in the houses. Nevertheless, their traditions were transformed with the Spanish colonization and are still changing significantly together with globalization. Even though it is very rich in natural resources, it has remained relatively poor in terms of economic resources in comparison to the rest of the country. That has caused a slower urban development, except for some periods of the 20th century, when oil extraction generated a rise of the economy and the population. The natural conditions make it also a region where it has been challenging to develop. On the one hand, the extremely humid and hot climate has impacted different aspects of every-day living. On the other hand, it is a highrisk seismic area, where earthquakes have affected the constructions in many occasions along history. However, it is also a region where community structures have reacted cohesively to these obstacles and almost every aspect of their lives.

According to INEGI (2015), the region that is defined as Istmo in Oaxaca is formed by 41 munic-

ipalities. However, most of the settlements and population are concentrated on the south, close to the

Pacific Ocean, which was the centre of this study. The analysis and the mappings are focused on sixteen municipalieties that are shown in figure 101. The field research was carried out in three municipalities that have a long history and areas with high socio-economic contrast, which are Tehuantepec, Juchitan de Zaragoza, and Asuncion Ixtaltepec. The three municipalities are located, as most of the settlements of the region, within a tropical wet and dry climate (Aw). These are also municipalities that were recently profoundly affected by a series of earthquakes that hit the region on September 2017, and therefore a considerable proportion of dwellings have been rebuilt or are still in the process of construction. A goal of this study was then to understand better the factors that have influenced the building traditions of the area throughout history and the ones that have a more significant influence over the new constructions.

3.2.1 SOCIO-CULTURAL CONTEXT

The interaction between the family and community structures, guided by indigenous and

colonial influences, has played a primordial role in the development of the housing typologies in the region. The socio-cultural context in Oaxaca is perfectly described by Maldonado Alvarado (2010) in three words: community, communality and colonialism. He does that in the context of education; however, these three words also represent some of the main factors that have influenced the housing sector. Community refers to a non-centralized structure of social organization that has explicitly predominated in this region since the establishment of the pre-colonial cultures. Communality refers to the collective system, in which tasks and resources are distributed and shared within each community. Finally, colonialism refers to the imposition of a culture that started with the Spanish domination, but that continues in different forms until nowadays. It may also refer to the parallel development of traditions and rituals from the indigenous, Spanish and other external cultures that have interwoven between one another.

189

INDIGENOUS, SPANISH, AND EXTERNAL INFLUENCE AND RITUALS

Different scattered groups from different cultures inhabited the Istmo before the arrival of

the Spaniards (Gómez Martinez, 2005). The first recorded groups to establish were the Mixe-Zoque, which were related to the Olmec Culture around 4,000 years ago. The next groups were the Ikooks or Huaves as they are commonly known, which probably came from Central America and settled along the coast. Consequently, the Zapotecs arrived from the centre of Oaxaca where their capital Monte Alban was founded. They became the most influential and most populated group from the region. It was also the predominating and ruling culture when the Spaniards arrived. According to Gomez Martinez, it is frequently believed that the Aztecs had control over the region; however, there is no archaeological or ethnohistorical evidence from that asseveration. Moreover, it has been demonstrated that even though there were a series of fragmented Zapotec settlements along the region when the Spaniards arrived, they all responded to one ruler called Cosijopí (de la Cruz, 1983). Even though the Spaniards imposed their culture as thoroughly as they could, there was much opposition from the existing inhabitants, who tried to maintain as much as possible their believes and traditions.

191

The influence of the Zapotec culture, which has some relation to the Mixe-Zoque and

Olmec Cultures, is reflected until today in the rituals and activities that are performed inside and outside of the house. The natural space, which is the exterior area of the houses, has always represented the primary space for activities within the house-holds in the IT. Marcus Winter’s (1986, 2004) archaeological work stands out for its detailed description of domestic units. The findings from the Zapotec Culture in Oaxaca were very similar to the ones from the Mixe-Zoque Culture in El Carrizal in the Istmo region. In general, the typical elements that he found in the majority of the units consisted of a closed rectangular space, which was dedicated mainly to sleep, external ovens dedicated to cooking and burning pottery, exterior wells to store grains, an exterior dump, and exterior space for burials. In some residential units, which probably belonged to the elite, several enclosed spaces were arranged to form a central courtyard, and one of the spaces was dedicated to burials. This basic configuration has evolved adapting to different circumstances, but the division of activities, having the exterior space as a primary element has endured until today.

Fig. 104 Municipalities of the Istmo region. Made by author with information from INEGI (2010)

10 km

In the Zapotec Culture, nature was part of their religion. As described by Marcus & Flan-

nery (1994), they had an animatistic religion, attributing life to different elements of nature. They worshipped, for example, corn, animals, lightning, and earthquakes. They also worshipped their ancestors who were depicted in the form of pottery figurines that were kept close to their burials next to the house or even inside of one of the rooms. The burials were also covered with offerings like pottery and precious stones. The different rituals related to death were then mixed with the Catholic rituals that were imposed by the Spaniards. After the 17th century, the burials were assigned to a cemetery; however, the space in the house dedicated to the worship of the death and their representation stayed in the form of altars, which occupied a primordial spot. The figurines also stayed as part of the altar and the interior space, but were then dedicated to Jesus, Mary and different saints. The rituals of the transition process to death also took and still take place regularly inside of the house. Therefore the main space of the house had to be relatively big to host the family and friends that visited during the funerary process, and also the spirits of the ones that are already gone (Peterson Royce, 2013). This main space was and is still called Yoo Bidó, which in Zapotec means house of saints.

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192

After the Spaniards took Tenochtitlan in 1521, they started to consolidate their power

along the Mexican territory. When they arrived in the Istmo in Oaxaca, they found a series of scattered groups along the rivers and streams, a situation that hindered the tributary and spiritual control of the natives or Indians, as the Spaniards used to call them. Nevertheless, different epidemics generated a severe decrease in the Indian population, which the Spaniards took advantage of to congregate the survivors into towns (Gerhard, 1975). It was then that different Indian towns were founded in the region like Juchitan, Salina Cruz, Ixtepec and Asunción Ixtaltepec. Tehuantepec (name given by the Aztecs), which was the main settlement of the Zapotec Culture, is where the majority of the Spaniards in the region also settled (Prévôt-Schapira, 2009). Since then called Villa de Tehuantepec, it acquired the typical features of the Spanish city. A rectangular grid, which was adapted to the terrain, guided the urban structure at first. The Spaniards and the elite lived close to the centre differentiating their housing typologies from the rest of the population. The grid was also imposed in the different Indian towns across the region; however, all of them had a predominance of indigenous population, which was also reflected in the housing typologies and block structure.

Fig. 105 Typical adaptation of the Zapotec dwelling into the urban grid imposed by the Spaniards. Made by author with information from Winter (2010) and Prévôt-Schapira (2009)

water well

oven room patio

193

Yoo Bidรณ

1:200

Altar

During the 17th and 18th centuries, the economic and population growth of the region

was low but stable. The economy was basically based on agriculture, cattle, fish and sand (GĂłmez Martinez, 2005). Most parts of the productive land were distributed in the form of haciendas. The region was part of a commercial route between the centre of Mexico, the Gulf of Mexico, and Central America. However, the severe climate conditions and the constant presence of epidemics hindered its commercial potential and further economic growth. By the end of the 18th century, it was one of the less populated regions of the country. The distribution of the population was 79.2% Indians, 8.3% Spaniards, and 12.4% Mestizos (Reina, 1999). That of course was reflected in the settlements, which maintained an indigenous predominance with a particular combination of traditions. The typologies also maintained their clear differentiation, which was explained in the previous chapter, between the haciendas, the Spanish city concentrated mainly in Tehuantepec, and the Indian Towns, which were distributed everywhere else.

Istmo, which means Isthmus, is the narrowest region in Mexico between the Pacific and

the Atlantic Oceans. After Mexicoâ&#x20AC;&#x2122;s independence, this condition generated interest between different countries like the United States, France, and England to establish an interoceanic commer-

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194

cial route. For this reason, by the end of the 19th century, a railway route was installed with private American investment. The commercial impetus, supported by a neoliberal model of consumption, resulted in economic growth. The settlements that benefited the most and that first to experience urban growth were Tehuantepec, Ixtepec, and Juchitan, where the wealthiest families established. The temporary economic growth ended with the opening of the Panama Canal in 1915. From that point on, the change of mentality, in which European and American models are followed in search of progress started to hit as well this region. Indigenous and Spanish traditions started slowly to be combined with foreign influences. However, an oligarchy of Zapotec groups also flourished, which helped to keep their traditions and language alive until today (Reina, 1999).

Until the 1940s the economic and population growth almost stopped, having even a de-

crease of population in the region. From that point onwards, the economy started again to rise, due to the construction of highways that connected the region with Central America and the rest of Mexico and also based mainly on the extraction and processing of oil. These activities first started on the Atlantic coast, but between 1974 and 1983, a refinery was built in Salina Cruz. In

those two decades, the population almost doubled in the south region, from around 120,000 to 230,000 inhabitants, concentrated mainly in the cities of Salina Cruz, Juchitan, and Tehuantepec. The immigration came mainly from the region and the neighbouring states. (Hernández García, Lelis Zaragoza, Alonso Gutiérrez, Islas Rivera, & Torres Vargas, 2006). The uncontrolled growth started to affect the social and urban fabrics in the cities. Self-constructed neighbourhoods started to fill the land, and territorial conflicts started to spread among the inhabitants. Different groups began to express their dissatisfaction. A movement led by the workers, farmers, and students party (COCEI) arose many questions regarding the search for progress. A text written by Carlos Monsivais (1983, p. 14), reflects perfectly the situation that was lived in the streets of Juchitan, but that was also taking place in other cities of the region. Some of the questions posted by Monsivais are:

“How can a non-urban town be urbanized and technified? How to go from a self-consumption economy to an industrial performance system? How can local ideologies persist in an increasing integrated country? Is it possible to save traditions? Does a religious verb like “save” apply to this context? Will indigenous identities survive or will they continue to be transformed? Will they resist to the industrial devastation? Will they resist to the migrations due to hunger and repression? Will they resist to the external learning of the ones that leave and come back “kwnowing different things”?”

After the 1990s, the economic, population and urban growth stabilized. Unlike what hap-

pened regularly in the rest of the country, despite the substantial changes in society, there is still a strong attachment to indigenous traditions in the region. The different social and political movements, together with the communal and cultural support have been essential in the further development of the region (Prévôt-Schapira, 2009). According to the census (INEGI, 2015), around 34% of the population in the region still speak an indigenous language, and around 66% considered

195

Population growth 350,000

300,000

200,000

150,000

100,000

Population

Year

Fig. 106 Population growth . Made by author with information from INEGI (2010)

2015

2010

2005

2000

1995

1990

1985

1980

1975

1970

1965

1960

1955

1950

1945

1940

1935

50,000

1930

3. Case Studies | The Influence of the Vernacular

196

Number of inhabitants

250,000

themselves indigenous. This attachment to their roots can still be perceived in the rituals, the festivities, and the family and social relations; however, many other aspects have yielded to a global culture, one example is clothing. As explained by Julia Lopez, a clothing manufacturer, owner of the local brand called Xhiurabe, the Istmo has a long history of textile and clothing makers. She assured that the market, mainly among young consumers, had been absorbed by global brands and trends and that textiles and even traditional outfits, had been lately imported as imitations from China. Nevertheless, she thinks that lately there has been a revival of traditions in the region, which was pushed forward after the earthquakes of September 2017, when local production gained again interest, which helped the local market (J. Lopez, personal communication, March 21, 2018).

A similar situation happened with architecture at the end of the 20th century and begin-

ning of the 21st century. Building traditions were replaced in many cases by the generic concrete cubic constructions that filled the entire Mexican landscape. Many typological and building material conditions were modified due to similar factors like the ones that affected the urban sprawl in the MMA, previously described in the last section. However, there are still significant differences that have to do mainly with the influence of the vernacular cultures, which have left and still leave a more notorious presence in the constructions. Another critical difference is that in contrast with the MMA, there has not been a significant influence of private developers in the construction sector. Even though more than 99% of the constructions in the region are single-family-houses (INEGI, 2015), they are mostly developed by the owners, which gives certain personal identity to the constructions in opposition to the repetitive typologies that have filled the land of other regions in central and northern Mexico. As in the case of clothing, local building traditions have been re-valued after the earthquakes; however, there are still many other factors that continue to influence their transformation, and that will be explained in the next sections.

COMMUNITY, COMMUNALITY, AND SEMI-OPEN STRUCTURES

Mesoamerican communities of the Istmo Area were formed by several families that lived

close together and that shared power, tasks, festivities and territory, having as a base their social tissue. According to Maldonado (2010), these shared characteristics that define communality are

197

3 500

198 Building a sense of community | The Influence of the Vernacular

500

7 9 8

Topography line River Underground river Highway Train track

still present in many of the rural towns of the region and in general in a great part of the society, where women have a primordial role. Power is shared in the form of assemblies, where all the community participate in making decisions. Tasks are shared with an organizational form called tequio, where the different members of the society work for free and share their knowledge to achieve common goals. Festivities, which are mainly religious, are shared and celebrated together by all the members. Finally, the territory is shared in the form of ejidos, where the property of the productive land is equally divided among the families. Maldonado explains that opposite to communality, there also exists individualism, which was mainly introduced with the â&#x20AC;&#x153;westernizationâ&#x20AC;? of the culture and the urban way of life. Therefore, even though communality and the sense of open structures still exist in different forms, it is getting lost, giving more and more space to individualized and closed structures.

The same phenomenon can be perceived in the urban and housing configuration. The

Mesoamerican built space of the communities was considered open, as the constructions were scattered freely adapted to the landscape. As explained, the areas of the house were separated, and the different daily activities were mainly performed outside, many times together with the community. Another variation was the houses that were separated by a close distance, which probably belonged to different members of the family (Winter, 1986). This practice is also common until nowadays, as it is usual to find different generations living in different structures within the same plot. The trees became the main elements for the positioning of the constructions, as their shadow was essential to keep a microclimate, where the daily outdoor activities took place. With the arrival of the Spaniards, loggias also became an essential element to give shadow to outdoor spaces. They also introduced a more closed typology and urban structure, which marked the beginning of the transitions into a more individualized culture.

Probably the main element that modified the spatial configuration of the settlements with

colonization was the street grid system, which predominates in the region until today. The streets and the division of the blocks gave a limitation for the positioning of the new constructions when the Indians were relocated into towns. The open and divided spaces remained, but within a contained territory that was not anymore shared. That created a condition of a semi-open block configuration, which was in the majority of times delimited by constructions on the outside perimeter

Fig. 107 Situation map of the IT with topography, urban sprawl and rivers. Made by author with information from INEGI (2010)

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but remained scattered to the inside. The growth within the plot generally followed a construction process that consisted of adding separate rooms or volumes depending on the needs of the families. That means adding, for example, a separate bathroom, kitchen or sleeping rooms for a different generation of the family.

Security, as in the case of the MMA, also became an essential aspect after the fast urban

and population growth from the 20th century; however, it did not generate the same effect of social segregation. There are, for example, almost no gated communities in the region; nevertheless, most of the plots are protected with a gate or a fence. In many cases, the windows are also protected with burglar bars. On the same way, opposite to what happened in the MMA, the car did not play a primordial role in the development of the settlements. They are generally parked on the streets, so in most cases, they do not occupy an area of the plot. For this reason, the normal growth and division of cities do not apply the same to this context. Apart from some specific cases in Tehuantepec and Juchitan, there is no clear distinction between the CBD and the suburbs.

Even though there are not significant differentiations between the socio-economic classes

in comparison to other regions of the country, there is a disparity in the degree of marginalization that has generated areas of contrast within the settlements. The main differences can sometimes be found in size and the finishes of the constructions, but in general, the housing typologies have followed similar forms between the different groups. According to Ziccardi (2015) the Mexican southern region keeps the lowest percentages of the country in terms of housing size. The most significant proportion of the inhabited dwellings, 26.9% have less than 40m2; 26% have from 41 to 60 m2; 20.4% from 61 to 90 m2; 4.2% from 91 to 120 m2; and only 0.3% have more than 120 m2. These numbers represent a slower economic development, but also a different life style in which the everyday needs are perceived in a different way in comparison for example to the north of the country. In the Istmo region, because of the similar conditions among most of the dwellings, it is not so easy to define a segmentation of typologies; however, based on the division made for the MMA several patterns can be organized to enunciate three main housing types.

Fig. 108 Degree of marginalization in the IT. Made by author with information from INEGI (2010)

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SEMI - OPEN TYPOLOGY

This type represents the majority of the constructions in the region. It has as a base the

variation from the Mesoamerican open structures that was adapted to the street system after the arrival of the Spaniards. The density of volumes within the plots is dependent on the economic situation and the needs of each family. They have regularly one storey, but in some cases, they reach two or three stories. The remaining open space kept its function as a central gathering area for the different members of the family and the neighbours, where most of the communal activities take place. The main volume faces the street typically, and additional volumes are placed depending on the trees or the relation to the neighbouring constructions.

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Fig. 109 Schematic representation of a semi-open typology urban distribution. Made by author

CLOSED TYPOLOGY

As there was only a small Spanish population in the region, the typical closed courtyard

typology, which was replicated along the country, did not appear so often in the Istmo Area. It was mainly introduced in the centre of Tehuantepec, where this population was mainly established. The closed typologies also appeared in some cases in Salina Cruz and Juchitan, where the high density in some areas mostly with informal settlements forced the inhabitants to build very tight configurations.

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Fig. 110 Schematic representation of closed typologies in an urban context. Made by author

DETACHED TYPOLOGY

These typologies are mainly the reflection of the individualized and â&#x20AC;&#x153;westernizedâ&#x20AC;? cul-

tures that have extended lately along the region. It belongs mainly to families from a high socio-economic sector. It has an evident influence on the suburban ideal; however, they only appear rarely, distributed in different areas of the settlements.

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Fig. 111 Schematic representation of detached typologies in an urban context. Made by author

As explain by Maldonado (2010), the tendency to move into cities or to transform the rural into urban has caused a distancing of man from nature. It has determined the transition of open community structures where the activities are done outside into closed individualized structures where life happens mainly indoor. The modern city that can be observed in Mexico is characterized as the opposite of the rural community. It is the opposition between individualization and collective life, between the unwillingness to govern and the lengthy and costly exercise of free service to the community, between contact with nature and its disappearance under the asphalt. In this region, there has been a constant struggle between these two worlds, so the search for a balance remains inevitable to meet the future needs of the population.

3.2.2 SITE AND CLIMATE

The area of study can be considered problematic in terms of physical habitability. There

are mainly two factors that have hindered and shaped the building dynamics in the region: the uncomfortable climate conditions and the earthquakes. It is also a region that has remained somehow isolated. Most of the settlements are located on a plain that is surrounded by mountain ranges, the one called Sierra Atravezada to the north, and the Sierra Madre de Oaxaca and Sierra Madre del Sur to the west. It is also surrounded by rainforests to the north, west, and east, and by the Pacific Ocean to the south. That means that it is mainly bounded by large uninhabited regions, keeping it relatively far away from Oaxaca City, the capital of the state, and other important cities and commercial nodes. All of these conditions have significantly affected the development of building traditions within the housing sector.

The predominant wet and dry climate (Aw) is mainly generated by hot air circulation com-

ing from the Gulf of Mexico to the north, which in summer is humid and in winter is dryer. The region is also affected by a climate phenomenon called El NiĂąo that occurs in intervals of around ten years producing strong winds and rain. On the one hand, the region has been therefore affected many times by floods through its history, and on the other, it has also suffered from long periods

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Fig. 112 Average temperature per hour in Tehuantepec. Made by author with information from Venture (2019) Fig. 113 Maximum and minimum average year temperature in Tehuantepec. Information from Venture (2019) Fig. 114 Average wind speed in Tehuantepec. Made by author with information from Venture (2019)

of draughts (Briones Gamboa, 2008). These climate conditions remain almost the same within the three different cities where the field research was carried out (Tehuantepec, Juchitan de Zaragoza, and Asuncion Ixtaltepec). Thus, similar reactions or adaptations to the climate could be expected in the housing sector.

TEMPERATURE

The temperature as in most hot humid climates is characterized for being relatively high

and constant throughout the year. There are only small variations between day and night from around 6°C to 9°C. The average high temperatures during the day vary only from 30°C to 35°C and the average low temperatures at night vary from 22°C to 26°C. Therefore there is almost no clear differentiation between seasons in relation to temperature. If we contemplate that the thermal comfort range for humans is between 20°C and 24°C, most of the year would be considered hot and probably uncomfortable. Thus, creating microclimates with passive cooling strategies is primordial in this region to achieve thermal comfort in the buildings. 207

WIND

This region is considered one of the windiest of the world. The predominant wind comes

mainly from the north, from the Gulf of Mexico and through the entire isthmus. The period from October to April usually is windier, when in average wind speed usually ranges from 5.6 m/s to 7.8 m/s; however, it can sometimes reach up to 60 m/s. These strong winds are also related to the El Niño phenomenon, and their regularity has been increasing lately (Briones Gamboa, 2008). The rest of the year the average speed ranges from 3.9 m/s to 7.1 m/s

SOLAR RADIATION

The solar radiation is higher in winter reaching an average of 7.1 KWh/m2 and lower in

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Fig. 115 Sun path in Tehuantepec. Made by author with information from Sun Earth Tools (2019) Fig. 116 Comfort according to humidity in Tehuantepec. Made by author with information from Venture (2019) Fig. 117 Average rainfall in Tehuantepec. Made by author with information from Venture (2019)

summer, which matches with the cloudy period, with an average of 4.5 KWh/m2. The region is located within the 16th parallel north, which means that the sun has regularly a relatively low inclination. It reaches its lowest point in the winter solstice with a solar elevation angle of 50ยบ.

DEW POINT, HUMIDITY, AND PRECIPITATION

Another characteristic of the climate from this region is that the dew point remains rel-

atively high throughout the whole year. Thus there is a constant high relative humidity, which also generates high levels of discomfort for humans. Around 76% of the time throughout the year conditions are muggy, oppressive or unbearable and during summer months, June to September, this occurs 100% of the time (Ventures, 2019). During those months it is also when high levels of precipitation are common, with an average total rainfall accumulation that ranges from 150 mm to 210 mm. During the rest of the year, the chances of precipitation remain very low. The high dew point levels are also reflected in the vegetation of the place, generating the right conditions for crops to grow, which need relatively less irrigation. That has been taken advantage of by the inhabitants of the region who have used the land for production.

BUILDING ADAPTATION TO THE SITE AND CLIMATE

Since the Spaniards arrived and the new towns were shaped, there was a relatively good

adaptation to the site and the extreme climate conditions. The physical isolation of the region led to certain independence in terms of management of regional natural resources and water. From the beginning, the inhabitants took advantage of the abundant natural surroundings to gradually improve their life quality. Until the 1960s, apart from the social difficulties that were produced with colonization, the IT had a controlled, sustainable development, based on regional production and consumption of goods and services. Such development was also reflected in architecture, where a careful selection of building materials and design strategies can be observed in most of the constructions that were built during that period. Most of the problems in the building sector that can be perceived nowadays arose with the uncontrolled growth of the population that began in the

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1970s, which are characterized by very short-term planning and urban sprawl, and the different consequences that this type of growth entails.

On an urban level the rigid grid that the Spaniards imposed adapted perfectly to the flat

landscape where the towns were established. In most of the cases, it created a clear block organization and hierarchy of spaces. However, the orthogonal grids were also disrupted after the urban expansion and followed different patterns, mainly in the case of Juchitan, Tehuantepec, and Salina Cruz, which were the cities that suffered a greater transformation after the 1960s. It was also then that natural borders like rivers and hills were overpassed or were â&#x20AC;&#x153;swallowedâ&#x20AC;? by the (in most of the cases) informal settlements. The incorrect management of resources, for example, their disposal, has caused since then many problems like the blockage and contamination of rivers and water bodies. This transition from rural to urban and the migration from rural towns to the city had an adverse effect on the overall economy. As suggested by Michel & RibardiĂ¨re (2017), the cities could not offer enough services and jobs for the entire population, while the rural family businesses started to decay. Moreover, the new inhabitants regularly settled on the peripheries, far away from the urban resources of the central business districts. 211

In relation to climate, the typical housing typologies that were built in the IT before the

1960s had several characteristics, which responded adequately to the non-comfortable ambient conditions. According to average values from the standard ASHRAE 55, only around 2.5% of the time throughout the year there are comfortable levels for the majority of the population (values were taken with the aid of the software Climate Consultant; see (Milne, 2018)). Therefore, one of the purposes of the built environment should be to help the users to meet comfortable conditions for the other 97.5% of the time. To do so, several passive design strategies have been followed in the region, but that can be summarized in mainly two aspects: avoiding internal heat gains and maximizing natural cooling and ventilation.

In contrast with the MMA, there is no cold period during winter. There are high tempera-

tures that are maintained along the year with only small variations between day and night. Regularly, during the night, there are comfortable ambient temperatures; however, during the day, the high temperatures together with high levels of humidity and solar radiation generate overheating

Fig. 118 Climate in the IT. Made by author with information from INEGI (2010)

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Fig. 119 Psychrometric chart and design strategies with measured yearly outdoor values from Tehuantepec . Made by author with information from Milne (2018)

HUMIDITY RATIO - GRAMS OF MOISTURE PER KILOGRAM OF DRY AIR

inside the buildings. One strategy to avoid it, was for example to place the cooking area, which generates heat, on a separate space outside. In the same way, most of the activities were carried out on the courtyard, under the shadow of a tree, a loggia or a separate roof (Jimenez Vera, 2012). The use of ham-mocks is therefore also very common on the interior and exterior spaces for sleeping and resting. As explained by Jimenez Vera, many people used to sleep outside, where temperatures are generally lower and more comfortable than in the interior.

The ideal orientation that was generally sought was north-south, with overhangs to the

south façade to minimize sun exposure. When possible large openings were placed to the north, where the prevailing winds come from and therefore maximizing natural ventilation. Even though, there can be many obstacles that block the winds; they are the best way to get a cooling effect on the body in hot-humid climates. Several studies have demonstrated (Kiamba, Rodrigues, & Benson, 2014; Nedhal, Wan Harum, & Syed Fadzil, 2011; Stathopoulos, 2009) that when kept at velocities from 0.2m/s up to maximum 5.0m/s, wind can significantly improve the comfort satisfaction. It can generate a reduction that equals up to 7°C on the thermal sensation. Nevertheless, north winds have to be managed with care in the region, because they can achieve higher speeds that can be uncomfortable and even dangerous for the users and the constructions.

As it can be seen in the psychrometric chart (figure 116), most of the measured climatic

values are somehow constant, keeping temperatures from 20 to 30°C with high levels of relative humidity throughout the year. This condition implies that most of the values stay outside of the comfort zone of humans. The passive design strategies to achieve comfort are therefore very limited, having natural adaptive ventilation as the most effective. The few values with lower temperatures are “easily” countered with solar gains and high thermal mass. However, comfort during the days with high temperatures can only be achieved with the use of dehumidification and air conditioning systems (Milne, 2018).

According to Szokolay (2000), there has been a conventionally accepted stereotype for

housing design in hot-humid climates, where lightweight constructions with low thermal mass were believed to have a better thermal performance than heavyweight constructions with high thermal mass. However, according to his studies and several others, both types of constructions

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perform good depending on several factors. Low thermal mass constructions that are constantly ventilated tend to follow the outdoor conditions and fluctuations closely, while with high thermal mass it can be easier to control and manipulate the dissipation and storage of heat. Nevertheless, if there is not a correct control from the users, for example, by not allowing night ventilation, high thermal mass can easily lead to overheating. In the case of the IT, most of the traditional houses were built on the ground, with adobe as the primary building material for walls and clay tiles as the main covering material for the roof. That means that most of the constructions were heavyweight and therefore the thermal performance depended on the correct ventilation of the spaces. In that sense, the transition from natural materials to the use of concrete as primary building material did not represent a significant variation in terms of thermal performance. However, it did imply a considerable increase in the grey energy of the constructions.

One more passive strategy that was used in the region to control the heat inside of the

constructions was the use of high ceilings. Typically, the houses were built with mono or dualpitched roof to avoid the concentration of water during the months with high precipitation. The roof height varied depending on the programme and the proportion of the room. The main volume

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regularly had from 4 to 6m height. Due to the physical properties of fluids, the warmer masses tend to rise, and therefore the heat was kept higher than the level of the users. Even though this only keeps a small temperature difference between the lower and higher air volumes (around 1 to 2Â°C), it has also represented a good strategy for heat dissipation in similar climates (GuimarÄ es, Carvalho, & Santos, 2013).

Even if the previously mentioned design strategies were followed, the indoor conditions

would still be uncomfortable for 67% of the time throughout the year; see (Milne, 2018). Comfortable conditions would generally be achieved by night, while during the day comfort would only be possible with the use of dehumidification and mechanical cooling systems. However, in the region, only around 9.4% of the housing constructions have an air conditioning system (INEGI, 2015), so the main strategy in most of the typologies for cooling is natural ventilation. Thus the transition from open and semi-open typologies into close structures, and outdoor into indoor life, affects the comfort of the inhabitants, as it is complicated to avoid and control heat gains in the interior of buildings. Understanding building and every-day traditions is therefore primordial to maintain

comfortable conditions in this type of climate and specifically in the IT.

EARTHQUAKES AND STRUCTURAL KNOWLEDGE

According to Kovach (2004), almost one-third of the total seismic activity in Mexico is

originated along the coast of Oaxaca, which is caused by the subduction of the Cocos tectonic Plate underneath the North American Plate. The plate motion provokes small earth movements almost every day; however, several strong earthquakes of magnitude 7.0 or more in the Richter scale are regularly reported (at least 25 in the past 100 years). The last strong earthquake occurred on the 7th of September 2017. The earthquake that had a magnitude of 8.2 and its subsequent aftershocks left extensive damages over the region. A significant number of constructions were partially or totally destroyed, which raised many questions regarding the building technologies that have been used over the past decades and the structural knowledge that has spread along the region.

It is believed as explained by Kovach that earthquakes in the region have affected not only

the built environment but also the entire culture since the first settlers arrived. As recorded in some archaeological sites of the Zapotec Culture like Monte Alban, there are indications of modifications in the structures of some of the main constructions possibly as a reaction to earthquakes (Villalobos PĂŠrez, 1986). One example is the evolution of wooden roofs and their efficient load distribution, and another example is the inclusion of buttresses as reinforcement of walls. However, there is no further evidence in this region regarding housing constructions from that time, and therefore it is not clear if the structural knowledge was shared among the whole population.

Most of the traditional houses that were built before the 1960s were not entirely ad-

equate for the seismic conditions. Most of them shared characteristics that are usually considered acceptable in seismic design. For example, they were generally divided into different volumes that had a compact shape. They also had relatively short spans, and the proportion of their sides kept a relation of less than 1:3, which is the maximum recommended for earthen constructions (Minke, 2001). However, as observed on site, the main problems among those buildings were that their walls lack tension elements and that the roof, which was heavyweight, was many times not con-

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Fig. 120-127

Situation of some buildings in the IT after the earthquake of September 2017. Taken by

author in March 2018.

nected to the walls or any vertical element. On the one hand, the walls were built regularly with adobe or brick; materials that react correctly to compression forces but that are not flexible. They normally did not use wood, bamboo or steel, materials that are typically added to complement the tension forces of the structure (Blondet, Vargas, Tarque, & Iwaki, 2011). On the other hand, the roofs that were regularly built with wood were only superimposed on the walls. Therefore, the different movement of the structural elements that lacked connection caused in many cases the roofs to collapse.

The shift on the use of natural materials to reinforced concrete after the 1960s, was in

many cases also a reaction to the lack of structural knowledge, as explained by Filiberto Lara, an experienced civil engineer that worked in the region after the 2017 earthquakes. The reinforced concrete has the advantage of being a monolithic structure that reacts to compression and tension forces. However, he is convinced that the use of steel as reinforcement has not been adequately done in the region. The fear among the inhabitants has made them over-reinforce the structures, which is also dangerous if it is not supervised and calculated. As he explained, residents themselves have built the majority of the constructions without a professional opinion, and the general structural knowledge varies from town to town. That also contributed to the fact that some towns were more affected than others with the last earthquake. The engineer also suggested that the same phenomenon is currently perceived, as there was a lack of training or information after the 2017 earthquake, the same mistakes are in many cases being repeated. The need of short term solutions and the lack of economic support has characterized the new construction process that has since then developed, and which is again reflected in the poor structural decisions that are being taken (F. Lara, personal communication, March 21, 2018).

3.2.3 CONSTRUCTION, MATERIALS AND TECHNOLOGY

The remote location and the physical isolation of the region generated a dependence on

local natural resources for constructions since the first settlers arrived. For many centuries natural materials like wood, reed, and earth constituted the primary sources for their constructions. How-

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ever, this changed during and after the urban expansion that started in the 1960s, where cement and steel, as it had had already happened in most of the country, became predominant. In contrast with the MMA or many other regions in the country, there was not an essential development of building material industries. This situation forced the import of materials from other regions like cement, pinewood and steel, which elevated the costs and grey energy of the constructions. It also forced in less proportion the further development of small local producers like in the case of brick, adobe, and tropical wood. Nevertheless, this has also produced a shortage in the supply of materials. A situation that became clear after the earthquakes of September 2017, when the high demand for materials and workforce generated a rise in prices and delays in many of the constructions (Chaca, 2017).

NATURAL RESOURCES, BUILDING MATERIALS AND TECHNIQUES

Even though the region is very rich in natural resources, which was taken advantage of

by the inhabitants for many centuries, it has not been exploited lately as other regions to meet

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the needs of the construction sector. The diverse geological characteristics of the region include sedimentary, igneous (intrusive) and metamorphic rocks, with ages ranging from the Precambrian to the Quaternary periods (Ramírez Hernández & Chávez González, 2003). Some of the igneous rocks, which was the first layer to form and that constitute the largest part of the subsoil, are still superficial and is where the granite, gravel, and sand are taken nowadays for construction purposes. The mountain ranges to the west were mainly formed during the Cretaceous period and consist of sediments where limestone can be obtained. The rest of the mountainous region to the north was formed during the Tertiary period and is rich in minerals. Finally, the area where most of the settlements were established was formed during the Quaternary period and consisted of an alluvium layer of sand, clay and lime, which has also been used in the construction sector.

The alluvium layer is also where most agriculture is obtained and where cattle are kept.

The rest of the organic layer that surrounds the region to the north corresponds to the rainforest vegetation characteristic of hot-humid climates. Among all the species that are found in the rainforest the most common that are used for construction are Guanacaste and Cocohite. To the south,

there is vegetation typical from the coast, with palm trees being one of the most common sources for construction in the region. Oak and pine can also be obtained in the district of Juchitan and Tehuantepec for construction purposes. However, they are mostly obtained from the Sierra Mixe, located to the north of the region. Even though there are ideal conditions for the controlled development of reserves, the unsustainable cut of trees and the frequent fires have caused a considerable reduction of resources (INEGI, 1997).

Although there is no physical archaeological record of the building materials from the

first inhabitants (Mixe-Zoque) that settled along the river Los Perros, it has been noted that they were influenced by the Olmec Culture (GonzĂĄlez & Winter, 2010). They possibly shared also similar building techniques, so they probably built using wood and earth as their primary sources to create bajareque walls, and wood and reed for the roof. The Huave culture that established along the coast also used palm wood doubtlessly for their constructions and palm leaves to cover them, a common practice that is still seen among the inhabitants until nowadays. After the arrival of the Zapotecs, the development of building traditions possible followed the evolution of the already advanced culture, also adding complexity to the housing structures. The first Zapotec settlers, who came from the central region of Oaxaca, probably introduced the adobe technique, which became predominant for the construction of walls in the region. The houses from the elite were built over a stone plinth, and the walls were covered with an earthen plaster (Winter, 1986). The pitched roofs were still covered with reed or palm leaves. This typology was called Yoo SiiĂąa, which in Zapotec means house of clay with palm roof (FAHHO, 2018).

When the Spaniards arrived in the region, the typologies from the high classes started to

transform. The adobe technique was in many cases replaced by burned bricks, which added resistance and durability to the wall constructions. The walls were plastered and painted mostly with one or two colors, influenced by the Zapotec and Aztec cultures. The palm or reed roofing also started to change. The structural beams, called morillos, were covered with wooden planks, known as biliguanas, which were then covered with a layer of clay, and then burned clay tiles were placed on top, a technique that was taken from the Arab culture and which the locals called tejavana. The floors were also covered with flat clay burned tiles. The doors and windows were also made out of wooden planks and branches. All the materials were collected from the site or very close to it. The

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stones were taken from the rivers, the clay was taken from the alluvium layer, and the wood was cut from the surrounding rainforest. This typology, which as explained before consisted of different volumes, soon became the standard of the region. Regardless the social class, it also became an aspiration to the inhabitants, who found with it a collective identity, recognizing it as the casa Tehuana, explicitly named after the region of the Istmo de Tehuantepec (Jimenez Vera, 2012).

During the 1940s another significant transformation began in terms of building materials

and techniques with the introduction of cement into the market. In 1942 the only cement industry from the region was opened (Martínez Laguna, Sánchez Salazar, & Casado Izquierdo, 2002). At first, it supplied cement mainly for the big infrastructure projects; however, soon it also altered the housing sector. Concrete played as in many other regions in Mexico a primordial role in the urban expansion that started in the 1960s. As already explained, concrete blocks and reinforced concrete structures, started to replace the adobe and brick walls. Many times, what was kept the same was the form, the distribution of the houses, the clay tiles on the roof and the floors and the colors and details that ornamented the façades. Nevertheless, sometimes the techniques, form, and materials were completely exchanged by cubic volumes made out almost totally with concrete. The wood on the doors and windows was replaced by glass, aluminium and iron. Also, ceramic tiles replaced the clay tiles. The problem in this region is that in contrast with the MMA almost none of these materials are extracted or produced locally. Except for cement, most of the materials like steel, glass, aluminium, iron and ceramics, have to be imported sometimes from far distances, which again increases the energy consumption and carbon emissions. Moreover, the generic construction techniques are transforming the regional identity into, arguably, towns without an architectural identity and aesthetic harmony.

MATERIAL INDUSTRY AND MARKET IN THE 21ST CENTURY

Industrialized materials have entirely absorbed the housing construction market in the

region. There are just a few independent producers that still work with traditional materials and building techniques. According to for example to Naymar Antonio Ortiz, a local producer of adobe blocks, the knowledge and the local building traditions are getting lost. She is the leader of the organization Yoó Béñe, the Zapotec words for “adobe house”, which was created after the earthquake

Fig. 128 Vegetation in the IT. Made by author with information from INEGI (2010)

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as an attempt to promote the production and use of adobe for the reconstruction of some damaged properties. The organization also encouraged the work with tequio, in which the community shares the labour. As Naymar explained, the economic support given by the government after the earthquake was not sufficient, and besides, the prices of materials and labour rose exponentially, so they emerged as an alternative low budget and sustainable solution to the problem. Nevertheless, most of the people that lost their houses were looking for immediate solutions and took what was readily available in the mass market, which was concrete, steel, and in a few cases burned brick. Therefore, she believes that vernacular building techniques will soon be forgotten in the region (N. Antonio Ortiz, personal communication, September 26, 2018).

According to the National Census (INEGI, 2015), by 2015 there were 86,751 inhabited

dwellings in the studied region. From that total 96.0% used brick or concrete block as the primary material for the construction of walls, 1.8% used adobe and wood, and 1.3% used bajareque or reed. For the roof construction 78.3% used reinforced concrete, 14.4% used metallic or asbestos sheet, 6.3% used the traditional tejavana, and 4.7% used card-board or waste materials. Finally, for the floor, 94.6% were built with concrete, from which 79.1% was left exposed, and 15.5% had tiles or wooden flooring; the other 4.9% had compacted earth floor. According to the SecretarĂa de Desarrollo Agrario, Territorial y Urbano (2017), an instance from the Mexican Government, 31,519 were affected with the earthquakes of September 2017 in the Istmo de Tehuantepec in Oaxaca. Many of those constructions were built before the 1960s in the traditional style. Therefore, even though there has not been a national census after the earthquake, it can be expected that the number of houses with natural materials was reduced, and the use of reinforced concrete increased in the new constructions.

With a lack of competition in the building material sector, there have been some com-

Fig. 129 Material extraction and industry over geomorphology map in the IT. Made by author with information from INEGI (2010)

10 km

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has been guided by the continuous search of their users to maintain the existing traditions. Others have preferred to look for solutions that will give a new identity to the city based on modern and post-modern principles. However, there are also people that have expressed the ideal to maintain a balance, to take advantage of new technologies and materials but without forgetting the principles of the vernacular building traditions.

According to the National Census (INEGI, 2015), by 2015 there were 86,751 inhabited

dwellings in the studied region. From that total 96.0% used brick or concrete block as the primary material for the construction of walls, 1.8% used adobe and wood, and 1.3% used bajareque or reed. For the roof construction 78.3% used reinforced concrete, 14.4% used metallic or asbestos sheet, 6.3% used the traditional tejavana, and 4.7% used cardboard or waste materials. Finally, for the floor, 94.6% were built with concrete, from which 79.1% was left exposed, and 15.5% had tiles or wooden flooring; the other 4.9% had compacted earth floor. According to the SecretarĂa de Desarrollo Agrario, Territorial y Urbano (2017), an instance from the Mexican Government, 31,519 were affected with the earthquakes of September 2017 in the IT. Many of those constructions were built before the 1960s in the traditional style. Therefore, even though there has not been a national census after the earthquake, it can be expected that the number of houses with natural materials was reduced, and the use of reinforced concrete increased in the new constructions.

With a lack of competition in the building material sector, there have been some com-

panies that have taken advantage of the excess of demand after the earthquake. The cement and aggregates industry, for example, massively increased their sales in the region, and the prices were elevated up to 30% (LĂłpez, 2017). That has also generated a transformation of the urban morphology. The gaps that were left by the collapsed constructions are now being filled by considerably smaller volumes that meet only the fundamental needs of the inhabitants, who will have to wait for a possible extension in the future. In many cases, the restoration or reconstruction of dwellings has been guided by the continuous search of their users to maintain the existing traditions. Others have preferred to look for solutions that will give a new identity to the city based on modern and post-modern principles. However, there are also people that have expressed the ideal to maintain a balance, to take advantage of new technologies and materials but without forgetting the principles of the vernacular building traditions.

Fig. 130 Satellite image of the Istmo region in Oaxaca (Google, 2019)

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11 10

3.3.3 SANTO DOMINGO TEHUANTEPEC

The city of Tehuantepec also gave the name to the entire Isthmus region. It has a long

pre-hispanic history. After several centuries of occupation of the Mixe-Zoque culture, the Zapotecs started to dominate the territory. They established their main settlement of the region 10 km Northwest from todayâ&#x20AC;&#x2122;s city centre, on a site called Guiengola, where the rests of the ceremonial complex can be found until today. The Spaniards chose then a close location to spread their dominion. They established an urban grid that can be seen (figure 128) on the east of the river, where today still stands the central plaza and the municipality. By the beginning of the 20th century, the urban sprawl started to extend to the west of the river, where the studied typologies are located. In these two areas of the city there are still many tehuana houses, which conserve the clear influence of the pre-colonial and colonial architecture; most of them built with colorful plastered adobe or burned brick walls and wooden and clay-tile-roofs. The rest of the urban sprawl that extends further east and west was mostly developed between 1980 and 2000, when the population doubled, from 28,443 to 57,153 inhabitants (INEGI,1980, 1990, 2000). Most of the exponential growth followed the cement-based way of construction, and part of it took the form of irregular settlements that still occupy different areas of the city.

The area of the city where the measurements and interviews were performed, was consid-

erably damaged with the earthquakes of September 2017. The first two cases, houses 10 and 11, almost entirely collapsed with the earthquake; however, their owners decided to re-build them with very similar style, and building techniques. They even reused the material that could be recovered from the old constructions, which were considered as the traditional typologies. One of the main reasons to build it similarly, as stated by two of the owners, was because of the comfort that they offered in comparison to other types of constructions, and to the adaptability to the climate. The city has a Tropical hot and dry climate (Aw), where it is complicated to achieve indoor comfort. The third studied typology was recently constructed as a cubic concrete construction. It did not suffer considerable damage with the earthquake; however, its comfort conditions are relatively worse than the other two examples from Tehuantepec.

Fig. 131 Satellite image of Tehuantepec, Oaxaca (Google, 2019)

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HOUSE 10

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Segmentation Builder Year of construction

Middle Architect / Owner Around 1800 - re-built 2018

Construction area

132.0 m2

Loggia/terrace area

151.1 m2

Garden/open area Inhabitants

42.5 m2 3 (43.0 m2 / person)

Exterior walls

Adobe (70 cm) / burned brick (15)

Interior walls

Burned brick (15 cm)

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Plaster

Walls structure Roof

Gypsum based mortar Burned brick Pinewood trunks (morillos), planks (biliguana), earth (10cm), clay tiles

Interior floor

Rammed earth, clay tiles

Exterior flooring

Rammed earth, clay tiles

Windows

Guanacaste doors, no glazing

Fig. 132 Axonometric view of house 10. Made by author Fig. 133 Ground floor plan of house 10. Made by author Fig. 134 Transversal section of house 10. Made by author

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Fig. 135 Exterior facade of house 10. Taken by author Fig. 136 Interior of Yoo Bidรณ of house 10. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (living room) 32.2 °C Temperature

Temperature 37.5 °C

46.5 % Relative humidity

Relative humidity 52.7 %

20.4 °C Dew point

Dew point 22.5 °C Illuminance 1500 lux

90 lux Illuminance

Wind speed 0.65 m/s

0.48 m/s Wind speed

Wall outer surface temperature 38 °C

34 °C Wall inner surface temperature

Roof outer surface temperature -

34 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

Apart from the extension that was built on the second floor, the house was re-built with

the traditional distribution and style. The main volume, which is the central area of the house is the Yoo Bidó, a space that acts as living, sleeping and altar room. The toilet and conventional sleeping rooms occupy separate volumes, and the kitchen is outside under a roof to avoid overheating. The terrace/loggia represents the largest area of the house as it is where the users spent most of their time. If they are indoor they stay in the Yoo Bidó, which, regardless of the relatively high measured temperature, is regarded as the most comfortable space of the house. This comfort is mainly achieved through natural ventilation, which was relatively high and consistent during the measured time (1 pm to 4 pm). As noted by one of the users, the air circulation is constant throughout the year and the space is kept fresh. The high ceiling (5.8 m. in the highest point) also contributed and the relatively good illuminance, also contributed to the comfort sensation (A. Palacios, personal communication, September 24, 2018).

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HOUSE 11

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232

Segmentation Builder Year of construction

Traditional Self-built 1895 - re-built 2018

Construction area

71.4 m2

Loggia/terrace area

42.7 m2

Garden/open area Inhabitants

161.2 m2 5 (14.3 m2 / person)

Exterior walls

Adobe (90 cm), burned brick (15 cm)

Interior walls

burned brick (15 cm)

Plaster GSPublisherVersion 0.0.100.100

Walls structure Roof Interior floor

Exterior flooring Windows

Gypsum based mortar Burned brick Pinewood trunks (morillos), planks (biliguana), earth (10cm), clay tiles Rammed earth, clay tiles Cement screed (7cm) Guanacaste doors, no glazing

Fig. 137 Axonometric view of house 11. Made by author Fig. 138 Ground floor plan of house 11. Made by author Fig. 139 Transversal section of house 11. Made by author

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Fig. 140 Exterior facade of house 11. Taken by author Fig. 141 Interior of Yoo Bidรณ of house 11. Taken by author

COMFORT MEASUREMENTS

Exterior average values (Loggia)

Interior average values (living room) 32.5 °C Temperature

Temperature 36.5 °C

50.5 % Relative humidity

Relative humidity 51.4 %

21.7 °C Dew point

Dew point 23.1 °C Illuminance 1600 lux

80 lux Illuminance

Wind speed 0.43 m/s

0.28 m/s Wind speed

Wall outer surface temperature 37 °C

34 °C Wall inner surface temperature

Roof outer surface temperature -

35°C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

In this house, most elements were recovered after the earthquake, as well as the materials

for the roof and the floor. The owners also recovered materials from other collapsed constructions in the neighbourhood. In that way, they could re-build the house almost as it was before. In this example, the main room is also the Yoo Bidó, where three of the inhabitants sleep and spend most of their time. The other spaces, a sleeping room, the kitchen and the loggia/terrace are mostly used by the other two inhabitants of the house. The interviewee rated the interior space as neutral in regard to her overall satisfaction, as during some periods of the year the room was too hot (A. Figueroa, personal communication, September 25, 2018). An explanation could be the relatively low air circulation that does not provide enough ventilation. The 90 cm adobe walls provide high thermal mass; however, in this climate, this strategy can generate overheating if there is not correct ventilation. That is why the temperature difference between the inner and outer surface is relatively small (3 °C), and the indoor temperature is relatively high, which generates discomfort.

235

HOUSE 12

Segmentation

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236

Builder Year of construction

Residential self-built 2003

Construction area

136.0 m2

Loggia/terrace area

49.2 m2

Garden/open area

26.6 m2

Inhabitants

3 (45.3 m2 / person)

Exterior walls

Concrete hollow blocks (15 cm)

Interior walls

Concrete hollow blocks (15 cm)

Plaster/finishing

Cement based mortar/vinyl paint

GSPublisherVersion 0.0.100.100

Walls structure Roof Interior floor Exterior flooring Windows

Reinforced concrete frame construction Reinforced concrete (12 cm) Cement screed (7 cm), ceramic tiles Concrete pavement Aluminum frame, single glazed

Fig. 142 Axonometric view of house 12. Made by author Fig. 143 Upper floor plan of house 12. Made by author Fig. 144 Ground floor plan of house 12. Made by author Fig. 145 Transversal section of house 12. Made by author

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Fig. 146 Exterior facade of house 12. Taken by author Fig. 147 Interior room of house 12. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (sleeping room) 34.6 °C Temperature

Temperature 36.3 °C

50.1 % Relative humidity

Relative humidity 53.0 %

22.7 °C Dew point

Dew point 22.7 °C Illuminance 1500 lux

70 lux Illuminance

Wind speed 0.40 m/s

0.26 m/s Wind speed

Wall outer surface temperature 38 °C

34 °C Wall inner surface temperature

Roof outer surface temperature -

40 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house belongs to a family that arrived in Thuantepec from a different state, and

therefore, they built their house with their known building traditions. That means as a conventional cement-based compact structure, which is common in the entire country. However, as stated by one of the users, the house does not respond adequately to the climate. The interior spaces are usually too hot, which affects their life quality, and that is why the overall comfort satisfaction was regarded as very uncomfortable. The measurements show that the interior temperature was constantly similar to the outside , but the air circulation was lower. Nevertheless, the user considered that there were no adequate terraces or open spaces in the house, a reason why she preferred to be usually on her mother’s neighbouring house. (M. L. Aguilar, personal communication, September 26, 2018). The measurements were carried out in the sleeping room, where she spent most of the time while being in the house. A problem observed in that room, located on the second floor, was the relatively high roof inner surface (40 °C), with a relatively low hight, generating radiant heat.

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14 15

3.3.4 JUCHITAN DE ZARAGOZA

Juchitan, the same as Tehuantepec, had a substantial proportion of Zapotec population

before the 20th century. It developed as an Indian town, where the typical Spanish grid guided the urban distribution. The first transformation of the city came together with the railway when the city extended to the Northeast towards the railway station. The second significant transformation occurred during the 1980s, along with the refinery that was installed in Salina Cruz, when the city drastically expanded in every direction. As previously explained, this event generated a dichotomy between the indigenous and the new population that came from different cities and towns from around the region. The city completely changed its character from urban to rural. This transformation is still undergoing, mainly after the earthquakes of September 2017, which considerably affected this municipality.

The selected typologies give an idea of the different influences that have predominated in

the city in the urban and rural areas. The first house, number 13, located in the CBD, has an evident influence of the Spanish typology because of its building materials, techniques, proportions, and facade elements. The second house, number 14, corresponds to a rural environment and to a lower socio-economic segmentation. It is built as the traditional indigenous construction that uses the available materials from the site, resulting in a lightweight structure. These two houses react in different ways to the extreme conditions of the Tropical wet and dry climate (Aw). However, natural ventilation is the principal mean used for cooling. The third example, number 15, is a typical example of a conventional self-built construction that has been built over several years, depending on the economic possibilities of the users. Many of these constructions are characterized for its cubic forms, for the cement-based building techniques, and for being unfinished. This situation increased after the 2017 earthquakes given the fast construction process that is undergoing in the city, and the availability of materials and construction knowledge. However, the adaptability of these type of constructions to the culture, site, and climate is not ideal, as regarded by some of its users.

Fig. 148 Satellite image of Juchitan, Oaxaca (Google, 2019)

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HOUSE 13

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Segmentation Builder Year of construction Construction area Loggia/terrace area Garden/open area Inhabitants

Middle Architect 2003 130.0 m2 1.8 m2 125.2 m2 3 (43.3 m2 / person)

Exterior walls

Burned brick (15 cm)

Interior walls

Burned brick (15 cm)

Plaster

Cement based mortar

GSPublisherVersion 0.0.100.100

Walls structure Roof Interior floor Exterior flooring Windows

Reinforced concrete frame construction Pinewood beams, clay tiles (2 cm), r. concrete (10 cm), clay arabic tiles Cement screed (7 cm), ceramic tiles Rammed earth, clay tiles Guanacaste wood, single glazed

Fig. 149 Axonometric view of house 13. Made by author Fig. 150 Upper floor plan of house 13. Made by author Fig. 151 Ground floor plan of house 13. Made by author Fig. 152 Transversal section of house 13. Made by author

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Fig. 153 Exterior facade of house 13. Taken by author Fig. 154 Dining room of house 13. Taken by author

COMFORT MEASUREMENTS

Exterior average values (courtyard)

Interior average values (dinning room) 31.2 °C Temperature

Temperature 34.4 °C

47.0 % Relative humidity

Relative humidity 48.2 %

24.4 °C Dew point

Dew point 21.6 °C Illuminance 1580 lux

40 lux Illuminance

Wind speed 1.05 m/s

0.35 m/s Wind speed

Wall outer surface temperature 33 °C

32 °C Wall inner surface temperature

Roof outer surface temperature -

32 °C Ceiling inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The house, which apart from the colors resembles a Spanish city typology, faces a court-

yard where a big nut tree gives shadow to most of the open space and the facade. During the measurements, the inside temperature remained lower than the outside, which is something common throughout the year according to the interviewee. The wind speed was relatively low in comparison to the outside values. That can be explained by the position of the windows in relation to the predominant winds, which was not ideas and did not allow crossed ventilation. However, that situation is usually complemented with the aid of a fan according to the user. The general indoor ambience was regarded as fresh, which was the main reason for the user to rate his overall satisfaction as very comfortable throughout the year (J. Magarino, personal communication, September 23, 2018). The heavy mass of the construction did not play a primordial role on the indoor temperature behaviour. That can be observed in the temperature surface, which remained similar on the inside and outside.

245

HOUSE 14

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246

Segmentation

Economic

Builder

Self-built

Year of construction

2007 (wooden-palm volume) - 2018 (cement-based volume)

Construction area

37.0 m2

Loggia/terrace area

7.8 m2

Garden/open area Inhabitants

252.0 m2 3 (12.3 m2 / person)

Exterior walls

Reed (2 cm)

Interior walls

None

Plaster

None

GSPublisherVersion 0.0.100.100

Walls structure Roof

Mezquite wood trunks and branches Mezquite wood trunks, palm leaves

Interior floor

Soil

Exterior flooring

Soil

Windows

None

Fig. 155 Axonometric view of house 14. Made by author Fig. 156 Ground floor plan of house 14. Made by author Fig. 157 Transversal section of house 14. Made by author

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Fig. 158 Exterior facade of house 14. Taken by author Fig. 159 Interior space of house 14. Taken by author

COMFORT MEASUREMENTS

Exterior average values (Garden)

Interior average values (living room) 31.9 °C Temperature

Temperature 32.6 °C

59.4 % Relative humidity

Relative humidity 62.1 %

22.1 °C Dew point

Dew point 23.5 °C Illuminance 1650 lux

300 lux Illuminance

Wind speed 1.74 m/s

0.56 m/s Wind speed

Wall outer surface temperature 32 °C

29 °C Wall inner surface temperature

Roof outer surface temperature 44 °C

29 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The wooden-palm house was built in 2007 by one of the owners together with his fami-

ly and neighbours, with materials also acquired from the community, by a previously mentioned practice known as tequio. Therefore its construction was done almost without monetary resources. After the earthquakes of 2017, the family also built a small cement-based room next-by as a precaution measure, where they sometimes sleep. However, the interviewee stated that it was regularly too hot and that she preferred the wooden-palm space, which was regarded as fresher and rated as very comfortable throughout the year. (S. Salinas, personal communication, September 29, 2018). Regardless of the relatively high indoor temperature, the low thermal mass and the openings in between the reed from the facade allowed relatively good ventilation, which is ideal for this type of climate. The indoor illuminance was also more adequate in comparison to other measured examples, which can also contribute to the sensation of comfort.

249

HOUSE 15

Segmentation

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250

Builder Year of construction

Middle Self-built 1981-2002 -2015

Construction area

105.0 m2

Loggia/terrace area

13.45 m2

Garden/open area

125.0 m2

Inhabitants

3 (35.0 m2 / person)

Exterior walls

Concrete hollow blocks (15 cm)

Interior walls

Concrete hollow blocks (15 cm)

GSPublisherVersion 0.0.100.100

Plaster/finishing Walls structure Roof Interior floor Exterior flooring Windows

Partly none, partly cement based mortar/vinyl paint Reinforced concrete frame construction Reinforced concrete (10 cm) Cement screed (7 cm) Cement screed Iron frame, single glazed

Fig. 160 Axonometric view of house 15. Made by author Fig. 161 Upper floor plan of house 15. Made by author Fig. 162 Ground floor plan of house 15. Made by author Fig. 163 Transversal section of house 15. Made by author

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Fig. 164 Courtyard facade of house 15. Taken by author Fig. 165 Living room of house 15. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (dinning room) 36.0 °C Temperature

Temperature 35.8 °C

55.0 % Relative humidity

Relative humidity 50.2 %

25.5 °C Dew point

Dew point 23.9 °C Illuminance 1580 lux

35 lux Illuminance

Wind speed 0.82 m/s

0.09 m/s Wind speed

Wall outer surface temperature 39 °C

34 °C Wall inner surface temperature

Roof outer surface temperature -

37 °C Ceiling inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house has been twice extended to accommodate more members of the family. It

stands on a plot that was shared by three generations. There were four houses within the plot; however, two of them suffered severe damage with the 2017 earthquakes, and are currently not inhabited. The measured conditions were very poor in terms of comfort. During the measurements, the house was overheated with a slightly higher temperature inside than outside. The indoor illuminance was also low to perform any daily activity, so the light was on most of the time while being indoors. The interior ventilation was relatively low, and the surface temperatures were high. According to one of the users, this situation was common, and that is why they spent most of their time outside on the courtyard or the terrace. The overall satisfaction in the indoor space was therefore rated as uncomfortable (A. Carrasco, personal communication, October 2, 2018). Overheating was then caused by a combination of factors, which in this case also included the production of heat in the kitchen, adjacent to the space where the measurements were done.

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16 17

3.3.5 ASUNCION IXTALTEPEC

Asuncion Ixtatepec is the municipality that was most affected by the earthquakes of Sep-

tember 2017, when almost 80% of the constructions were partially or entirely damaged. That has caused since then a continuous construction and renovation process, which has changed the image of the city. Its history dated from the 16th century when it was established as an Indian town. In contrast with the previous two municipalities, Asuncion Ixtaltepec had since then relatively controlled and stable growth. It kept a relatively high proportion of indigenous population, which is reflected until today in their traditions and lifestyle. Many of the damaged constructions were built with vernacular building techniques. The walls were made with adobe or burned bricks, and the sloped roofs were the typically called tejavana. The urban structure also used to maintain mainly the semi-open configuration, where a few relatively small volumes were distributed in each plot around fruit trees, and several plots formed a block. Some of the plots are being rebuilt with similar configurations, and the houses are rebuilt with the traditional style and building materials; however, the majority is following the cement-based type, compacting all the spaces in one volume.

This municipality also has a Tropical wet and dry climate (Aw), with relatively high tem-

peratures throughout the year, and challenging to reach comfort values. The examples where the measurements and interviews were performed are located to the west of the river Los Perros, which divides the city into two. The three cases are close to the CBD, where a greater influence of the vernacular is still present in the constructions. The first two, number 16 and 17, were damaged with the earthquake and rebuilt with a similar configuration and style than before. The first one with more economic resources than the second, but with the same goal of keeping a local identity, as stated by the two interviewed users. The third case, number 18, was built entirely new and different from the previously collapsed house. The adaptability to the site and the weather is also different, which was reflected in the results.

Fig. 166 Satellite image of Asuncion Ixtaltepec, Oaxaca (Google, 2019)

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HOUSE 16

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256

Segmentation Builder Year of construction

Residential Architect / Owner 2018

Construction area

81.7 m2

Loggia/terrace area

32.4 m2

Garden/open area Inhabitants

273.2 m2 2 (40.8 m2 / person)

Exterior walls

Burned brick (15 cm)

Interior walls

Burned brick (15 cm)

GSPublisherVersion 0.0.100.100

Plaster Walls structure Roof Interior floor Exterior flooring Windows

Partly cement-based mortar and vinyl paint Reinforced concrete frame construction Zapotillo trunks (morillos), planks (biliguana), r. concrete, EPS (3 cm), clay tiles Cement screed (7 cm), onyx tiles Cement screed (7 cm), clay tiles Aluminium, double glazed

Fig. 167 Axonometric view of house 16. Made by author Fig. 168 Ground floor plan of house 16. Made by author Fig. 169 Transversal section of house 16. Made by author

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Fig. 170 Exterior facade of house 16. Taken by author Fig. 171 Kitchen/dinning room of house 16. Taken by author

COMFORT MEASUREMENTS

Exterior average values (street)

Interior average values (dinning room) 34.9 °C Temperature

Temperature 36.8 °C

51.5 % Relative humidity

Relative humidity 54.3 %

25.6 °C Dew point

Dew point 26.0 °C Illuminance 1700 lux

45 lux Illuminance

Wind speed 0.94 m/s

0.46 m/s Wind speed

Wall outer surface temperature 35 °C

33 °C Wall inner surface temperature

Roof outer surface temperature 43 °C

34 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house was built by reusing as much material as possible from the collapsed construc-

tion, which included some of the bricks, the floor and roof clay tiles, the lintels, and the doors. All other materials were acquired from the region. Despite the relatively high measured temperature values, the overall satisfaction of the space was rated as very comfortable by the user. That was mainly attributed to different factors like the area where it is located, the quality of the space, the freshness and the good ventilation (A. S. Chavez, personal communication, September 30, 2018). The latter could be corroborated with the measured values, in which the wind speed was relatively constant thanks to the crossed ventilation that was kept through the loggia, the kitchen/dining space and the street. In this case the difference in the surface temperature of the walls did not show a representative value; however, the temperature difference from the roof was relatively high (9 °C), which could be attributed to the high thermal mass of the clay tiles and the and the high thermal resistance of the EPS panels.

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HOUSE 17

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Segmentation Builder Year of construction

Traditional Self-built aprox. 1920 - 2018

Construction area

70.5 m2

Loggia/terrace area

28.2 m2

Garden/open area Inhabitants

118.3 m2 3 (23.5 m2 / person)

Exterior walls

Burned brick (15 cm), Stone tiles (2 cm)

Interior walls

Burned brick (15 cm)

GSPublisherVersion 0.0.100.100

Plaster

Walls structure Roof Interior floor Exterior flooring Windows

Gypsum based mortar Reinforced concrete frame construction Cedar trunks (morillos), planks (biliguana), r. concrete, clay tiles Cement screed (7 cm), ceramic tiles Cement screed (7 cm) Iron frame, single glazed

Fig. 172 Axonometric view of house 17. Made by author Fig. 173 Ground floor plan of house 17. Made by author Fig. 174 Transversal section of house 17. Made by author

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Fig. 175 Exterior facade of house 17. Taken by author Fig. 176 Courtyard loggia of house 17. Taken by author

COMFORT MEASUREMENTS

Exterior average values (Street)

Interior average values (living room) 31.2 °C Temperature

Temperature 35.8 °C

46.5 % Relative humidity

Relative humidity 54.5 %

20.9 °C Dew point

Dew point 22.7 °C Illuminance 1400 lux

85 lux Illuminance

Wind speed 1.12 m/s

0.44 m/s Wind speed

Wall outer surface temperature 35 °C

31 °C Wall inner surface temperature

Roof outer surface temperature -

32 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

The house was partially destroyed with the earthquakes of 2017; however, many materials

were rescued and used for the new construction. The Yoo Bidó, which is the space used as sleeping, living and altar room was completely rebuilt and is where the measurements were taken. The other spaces that collapsed were also built in the same positions as before. According to the interviewed user, the house had everything they needed, and that is why they did not want to change it considerably. The overall satisfaction in the house was rated as very comfortable, even though the user spent most of his time on the terrace. The user stated that he usually opened all the doors and windows during the day to keep a good air circulation, which was also reflected on the measured values with an average wind temperature of 0.68 m/s. Another important factor for the user while rebuilding the house was the hight of the roof, which was 4.50 m on the highest point, and contributes significantly to the sensation of comfort. (J. C. Santos, personal communication, October 1, 2018).

263

HOUSE 18

Segmentation

3. Case Studies | The Influence of the Vernacular

264

Builder Year of construction

Middle Architect/Contractor 2018

Construction area

90.0 m2

Loggia/terrace area

34.6 m2

Garden/open area Inhabitants

438.1 m2 2 (45.0 m2 / person)

Exterior walls

Concrete hollow block (15 cm)

Interior walls

Concrete hollow block (15 cm)

Plaster/finishing

Cement based mortar

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Walls structure Roof

Reinforced concrete frame construction Reinforced concrete (10 cm)

Interior floor

Cement screed (7 cm), ceramic tiles

Exterior flooring

Cement screed (7 cm), ceramic tiles

Windows

Aluminium frame, single glazed

Fig. 177 Axonometric view of house 18. Made by author Fig. 178 Ground floor plan of house 18. Made by author Fig. 179 Transversal section of house 18. Made by author

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266

Fig. 180 Exterior facade of house 18. Taken by author Fig. 181 Living room of house 18. Taken by author

COMFORT MEASUREMENTS

Exterior average values (Street)

Interior average values (living room) 34.5 °C Temperature

Temperature 34.8 °C

46.0 % Relative humidity

Relative humidity 47.8 %

21.2 °C Dew point

Dew point 22.1 °C Illuminance 1290 lux

130 lux Illuminance

Wind speed 1.05 m/s

0.38 m/s Wind speed

Wall outer surface temperature 39 °C

36 °C Wall inner surface temperature

Roof outer surface temperature -

42 °C Roof inner surface temperature

User’s overall comfort satisfaction

very uncomfortable -3

uncomfortable -2

slightly uncomfortable -1

neutral uncomfortable 0

slightly comfortable +1

comfortable +2

very comfortable +3

This house was built as a reaction to the fear that was left after the earthquakes of 2017.

Its compact volume and the use of a reinforced concrete structure was primordial to the users that used to live in a traditional house before the earthquake. As stated by one of the owners, even though they do not find it completely comfortable, it gives them a sense of security, which was important for their quality of life. The low height of the ceilings and the high indoor temperatures were regarded as the most significant factor for the sensation of discomfort. Nevertheless, in the living room, where the interviewee spent most of the time, there was relatively good ventilation, which was valued as an essential factor for comfort. The air circulation was enhanced by an electronic fan, which the user kept on most of the time. Similar to the other two examples from Asuncion Ixtaltepec, the interviewed user preferred to stay outside of the house, as she considered it more comfortable than the inside (I. A. Pinon, personal communication, October 3, 2018).

267

4 RESULTS THE EFFECTS OF THE VERNACULAR INFLUENCE ON THE USERS

One of the ultimate goals of sustainable architecture is to improve the quality of life of

the users. According to the World Health Organization (1999) as described by Soares et al (2015), quality of life is defined as “an individuals’ perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns.” Therefore, the place where the majority of today’s society spends most of their time, namely the house and its surroundings, is expected to have a significant influence over their perception of life, health, and well-being. Within the house, there are plenty of factors that can affect the judgment of the inhabitants such as the psychological state of the members of the family or community, their personal believes, their social relations or the indoor environmental conditions, which produce thermal and visual comfort, or discomfort over the users. Thus, there is a consensus within the research community that objective and subjective indicators are necessary to measure the person’s relation to its environment (Cummins, 2000).

This study is concerned with the factors that are directly related to the architecture of

the house and the immediate physical surroundings. In this chapter, the results of the measured indoor physical conditions, the comfort survey, and the interviews with the inhabitants in each of the case studies are presented and compared. The intention is to understand better the effects of using vernacular building traditions and building techniques in opposition to the conventional constructions over the users’ comfort and quality of life. It is also to show the results of the study in two different locations, one with hot arid climate and the other with hot tropical climate, and to find correlations to their historical background and between one another. Moreover, the results concerning the quality of life between users with low and high socio-economic contexts are investigated and compared. Finally, the relation and views of the users towards sustainability and its relation to vernacular traditions are presented as a prelude to the final conclusions.

Fig. 182 User. Taken by author

269

Vernacular

High socio-economic segmentation

Low socio-economic segmentation

Conventional

10.

11.

12.

13.

14.

15.

16.

17.

18.

Garcia

Monterrey Metropolitan area

Monterrey

Santiago

Tehuantepec

Asuncion Ixtaltepec

Fig. 183 Matrix of the axonometric views of the studied typologies. Made by author

Istmo de Tehuantepec

Juchitan

4.1

CHARACTERISTICS OF THE HOUSES AND THE INHABITANTS

For this part of the study, eighteen houses were measured and studied, and one inhabitant per

house was interviewed. The houses, which were presented in the previous chapter, are shown in figure 181 as a diagrammatic summary for the reader to make an easier correlation to the furthered mentioned cases. Each house was assigned a number from 1 to 18, so in this chapter, the inhabitants are also numbered according to each of their dwellings. In this section, the general characteristics of the typologies and the inhabitants are presented separately for each of the case studies. However, this diagram already shows the first visual comparison and result between the selected houses. As suggested by Rapoport (1969), the form of the house can give a clear insight into a specific site and culture when following vernacular principles. As observed in the diagram, and without going into detail, all the examples that are classified as vernacular have a noticeable relation to their historical, physical and social contexts, which were described in the previous chapters. In contrast, the cases that are classified as conventional share similarities regardless of the region where they were built, which is more evident in the Istmo region simply because of the roof shape. Another visual distinction is the size of the construction that reflects the discrepancy between the socio-economic segmentation. Further relations that cannot be perceived with an axonometric view will be made in the following sections.

271

4 4

Predominant materials in roof

5 5

0 CEB

Garden area

Adobe

More than 100 m2

81 - 100 m2

Ceramics

Soil

61 - 80 m2

Wood

41 - 60 m

Fired brick

Wood

Construction area

Residential-plus

Residential

Middle

Traditional

Popular

Fired clay tiles

21 - 40 m2

Stone/Sillar

Economic

Number of houses

Less than 20 m2

Number of houses

Contractor

Architect

Developer

Concrete

Number of houses

More than 120 m2

91 - 120 m2

76 - 90 m2

61 - 75 m2

Self-built

Number of houses

Stone

Number of houses

More than 300 m2

201 - 300 m2

151 - 200 m2

101 - 150 m2

41 - 60 m2

Less than 40 m2

Number of houses

Concrete

Reed/Straw

Adobe/CEB

Wood

Fired clay tiles

51 - 100 m2

Less than 50 m2

Number of houses

272

Stone

Concrete

Number of houses

Building a sense of community | The Influence of the Vernacular

Primary designer/builder Segmentation

Terrace area

Predominant materials in exterior walls

Predominant materials in ďŹ&#x201A;oor

Fig. 184 Summary of results of the specific characteristics of the houses in the MMA. Made by author

MONTERREY METROPOLITAN AREA

The specific characteristics of the houses are as follow: primary designer/builder: 3 houses

were designed by architects and built by contractors, 3 were self-designed and built, and 3 were built by developers. Socio-economic segmentation: 4 were classified as residential-plus (high), 1 was residential (high), 3 were traditional (low), and 1 was classified as popular (low). The year of construction was: 4 were built between 2000â&#x20AC;&#x201C;2009, 3 were built between 2010-2018, and 2 were built in the 20th century but renovated/extended between 2000-2009. The average construction area was 167.4.0 m2 (s = 100.0), and the average occupation was 3.4 (s = 1.9) inhabitants per household with an average of 55.9 m2 (s = 31.9) per person; the average terrace area was 78.7 m2 (s = 97.5), and the average garden area was 1,364.0 m2 (s = 2,660.9). Nevertheless, the garden and terrace average areas are not representative as their standard deviation (s) are significantly higher than the median between the measured values.

From the six houses that are defined as vernacular: predominant material for the walls:

2 have sillar, 2 have compressed earth blocks, 1 has adobe, and 1 has massive concrete blocks; predominant materials for the roof: 3 of them use wood and concrete, and 3 of them use only reinforced concrete; predominant materials for the indoor floor: 3 of them use ceramic tiles, 1 uses fired clay tiles, 1 uses stone, and 1 uses polished concrete; plaster: 3 of them use gypsum-based mortar, 1 uses cement based mortar, and 2 do not use mortar; windows: 2 of them use PVC frame double-glazed, 2 of them use iron frame single-glazed, 1 uses aluminium frame single-glazed, and 1 uses pinewood doors without glazing. For the three typologies defined as conventional: predominant materials for the walls: The 3 of them use hollow concrete blocks; predominant materials for the roof: the 3 of them use reinforced concrete; predominant materials for the indoor floor: the 3 of them use ceramic tiles; plaster: the three of them use cement-based plaster; windows: the 3 of them use aluminium frame single-glazed. A summary of the total results for the nine typologies can be seen in figure 182, which can be used for easier comparison with the typologies from the Istmo region.

273

4 4

Predominant materials in roof

5 5

Fig. 185 Summary of results of the specific characteristics of the houses in the IT. Made by author Reed/Straw

Garden area

Adobe/CEB

More than 100 m2

81 - 100 m2

Ceramics

Soil

61 - 80 m2

Wood

41 - 60 m

Fired brick

Wood

Construction area

Residential-plus

Residential

Middle

Traditional

Popular

Fired clay tiles

21 - 40 m2

Stone

Economic

Number of houses

Less than 20 m2

Number of houses

Contractor

Architect

Developer

Concrete

Number of houses

More than 120 m2

91 - 120 m2

76 - 90 m2

61 - 75 m2

Self-built

Number of houses

Stone

Number of houses

More than 300 m2

201 - 300 m2

151 - 200 m2

101 - 150 m2

41 - 60 m2

Less than 40 m2

Number of houses

Concrete

Reed/Straw

Adobe/CEB

Wood

Fired clay tiles

51 - 100 m2

Less than 50 m2

Number of houses

274

Stone

Concrete

Number of houses

4. Results | The Influence of the Vernacular

Primary designer/builder Segmentation

Terrace area

Predominant materials in exterior walls

Predominant materials in ďŹ&#x201A;oor

The specific characteristics of the inhabitants that partook in the study in the MMA are as

follow: Gender: 5 female, and 4 male; Age; 2 are 30-49, 3 are 50-64, and 4 are 65 or older; Occupation: 2 work as salesman/woman, 2 work in the construction sector, 1 works in the industry sector, 1 works in the agriculture/fishing sector, 2 are retired, and 1 is unemployed.

ISTMO DE TEHUANTEPEC

In the IT, the specific characteristics of the studied houses are as follows: primary de-

signer/builder: 5 houses were self-built, 3 were designed by an architect and built by contractors, and 1 was designed and built by contractors. Socio-economic segmentation: 2 were classified as residential (high), 4 were middle (high), 2 were traditional (low), and 1 was classified as economic (low). The year of construction was: 2 were built between 2000â&#x20AC;&#x201C;2009, 2 were built between 20102018, and 4 were rebuilt in 2018, after they were totally/partially damaged during the earthquakes of 2017. The average construction area was 94.8 m2 (s = 33.7) and the average occupation was 3.0 (s = 0.9) inhabitants per household with an average of 33.7 m2 (s = 13.5) per person; the average terrace area was 44.1 m2 (s = 43.5), and the average garden area was 173.6 m2 (s = 128.8).

From the six typologies that are defined as vernacular: predominant material for the

walls: 2 have burned bricks, 2 have adobe, 1 has burned bricks and stone, and 1 has wood and reed; predominant materials for the roof: 2 of them use wood, concrete and clay tiles, 2 of them use wood, earth and clay tiles, 1 of them uses concrete and clay tiles, and 1 of them uses wood and palm leaves; predominant materials for the indoor floor: 4 of them use fired clay tiles, 3 of them use ceramic tiles, 1 uses polished concrete, and 1 has just soil; plaster: 3 of them use gypsum-based mortar, 2 use cement based mortar, and 1 do not use mortar; windows: 2 of them use iron frame single-glazed, 1 uses aluminium frame double-glazed, 2 use wood doors without glazing, and 1 does not have windows. For the three typologies defined as conventional: predominant materials for the walls: The 3 of them use hollow concrete blocks; predominant materials for the roof: the 3 of them use reinforced concrete; predominant materials for the indoor floor: 2 of them use ceramic tiles, and 1 uses cement screed; plaster: the three of them use cement-based plaster; windows: 2 of

275

them use aluminium frame single-glazed, and 1 uses iron frame single-glazed.

The specific characteristics of the inhabitants that partook in the study in the Istmo region are as follow: Gender: 4 female, and 5 male; Age; 1 is 18-29, 2 are 30-49, 5 are 50-64, and 1 is 65 or older; Occupation: 2 work in the agriculture/fishing sector, 1 works in the education sector, 1 works as administrator, 1 works as technician, 1 is retired, and 2 are unemployed.

4. Results | The Influence of the Vernacular

276

4.2

COMFORT

As already explained, comfort among other factor affects the quality of life, but at the same

time, several aspects have an influence over comfort. As stated by Ogoli (2007, p. 3), Humphreys defined comfort as â&#x20AC;&#x153;the absence of discomfort, and discomfort is alleviated by making adjustmentsâ&#x20AC;?. Discomfort in hot climates is regularly produced because of the thermal sensation that is generated by outdoor and indoor conditions such as air temperature, surface temperature, humidity, and air velocity. It can also be produced by low or high illuminance, noise or different psychological reasons. The adjustments according to Humphreys, in opposition to turning on the air conditioning, can be to open/close windows and doors to allow natural ventilation or to adjust the shading devices. The adjustments can also be related to self-behaviour like shifting position in the house, changing clothes, or modifying the activities in the house, which are many times embedded in the culture of a society. All of these factors were taken into account for the measurements and the surveys to the inhabitants. The results were compared between the MMA and the IT to better understand the different factors and usersâ&#x20AC;&#x2122; behaviour in relation to both climates. The results between the vernacular and conventional typologies are also presented to project the advantages or disadvantages of using certain building materials and techniques for the housing constructions in each of the climates.

277

Monterrey Metropolitan Area - Outdoor measured average values City

Air temperature

Relative humidity

Wall surface temp.

Wind speed

Illuminance

Garcia

33.4 °C

35.1 %

38.7 °C

1.0 m/s

1503 lux

Monterrey

33.3 °C

41.5 %

40.3 °C

0.4 m/s

1573 lux

Santiago

32.5 °C

49.2 %

38.3 °C

0.6 m/s

1512 lux

Total Avg.

32.9 °C

41.9 %

39.1 °C

0.67 m/s

1529 lux

Monterrey Metropolitan Area - Indoor measured average values Air temperature

Relative humidity

Wall surface temp.

Wind speed

Illuminance

Garcia

City

30.7 °C

34.3 %

32.0 °C

0.24 m/s

52 lux

Monterrey

30.8 °C

41.2 %

33.7 °C

0.22 m/s

277 lux

Santiago

30.2 °C

47.2 %

30.7 °C

0.27 m/s

32 lux

Total Avg.

30.5 °C

40.9 %

32.1 °C

0.24 m/s

120 lux

4. Results | The Influence of the Vernacular

278

Istmo de Tehuantepec - Outdoor measured average values City

Air temperature

Relative humidity

Wall surface temp.

Wind speed

Tehuantepec

36.8 °C

Juchitan

34.2 °C

Illuminance

52.4 %

33.7 °C

0.49 m/s

1533 lux

53.5 %

34.7 °C

1.2 m/s

1603 lux

Ixtaltepec

35.8 °C

52.2 %

36.3 °C

1.04 m/s

1463 lux

Total Avg.

35.6 °C

52.7 %

36.2 °C

0.91 m/s

1533 lux

Istmo de Tehuantepec - Indoor measured average values City

Air temperature

Relative humidity

Wall surface temp.

Wind speed

Illuminance

Tehuantepec

33.1 °C

50.7 %

34.0 °C

0.34 m/s

80 lux

Juchitan

33.0 °C

50.5 %

31.7 °C

0.33 m/s

125 lux

Ixtaltepec

33.4 °C

49.3 %

33.3 °C

0.51 m/s

87 lux

Total Avg.

33.2 °C

50.2 %

33.0 °C

0.39 m/s

97 lux

4.2.2 Relation of results between conventional All average values have a standard deviation vernacular of CV < 1 unlessand otherwise indicated typologies

it has beenmeasured proofedaverage in several Table 5 As MMA - Outdoor values research studies (Chandel, Sharma, & Marwah, 2016; Gulati R, 2014; Manríquez et al., 2006), the use of vernacular principles in architecTable 6 MMA - Indoor measured average values ture usually lead to better indoor comfort conditions for the inhabitants, in comparison Table 7 where IT - Outdoor average to cases suchmeasured principles arevalues not applied. Vernacular principles belong to a specific region; whymeasured in this average sectionvalues the results are compared separately for the Monterrey Table 8this IT - is Indoor Metropolitan Area and the Istmo region. The intention for this part of the study is to show a comparison of the objective comfort measurements and surveys, but also the point of view of some of the inhabitants towards their perception of comfort in relation

As an indicator of comfort this study considers the values proposed in the adaptive comfort

model ASHRAE Standard 55-2010. According to Milne (2018):

“In naturally ventilated spaces where occupants can open and close windows, their thermal response will depend in part on the outdoor climate, and may have a wider comfort range than in buildings with centralized HVAC systems. This model assumes occupants adapt their clothing to thermal conditions, and are sedentary (1.0 to 1.3 met). There must be no mechanical Cooling System, but this method does not apply if a Mechanical Heating System is in operation.”

According to this standard, acceptable comfort temperatures range from 18.9 to 29.7 °C in the

case of the MMA, and from 22.8 to 29.5 °C in the case of the IT, both with 90% of acceptability limits. Comfort in relation to relative humidity is more difficult to determine; however, 50 % can be taken as a standard for comfort (Nicol, 2004). The farther a value gets from this number, the more uncomfortable it gets. As previously mentioned, airspeed can increase comfort when kept from 0.2 to a maximum of 5.0 m/s. Finally, the comfort levels of illuminance depend on the undertaken activity; however, in the house they usually range from 100 to 300 lux during the day.

4.2.1 RELATION OF RESULTS BETWEEN ARID AND TROPICAL CLIMATES

The arid climate that is represented for this study by the Monterrey Metropolitan area

has as before mentioned 3 different climate subcategories. For that reason, the humidity values varied significantly between the three cities. The tropical climate, which is represented by the IT de Tehuantepec region presented similar conditions between the three selected cities. However, the eighteen comfort measurements were carried out on almost consecutive sunny days at the same time of the day (in between 1 and 4 pm) to guarantee similar climate conditions. The recorded exterior and average interior values are shown in tables 5 – 8. An important value to observe

279

Variables that are adjusted when feeling uncomfortable

8 8

7 7

6 6

3 5

0 Low ceilings

Fig. 186 Summary of the relation of comfort results between the MMA and the IT. Made by author Reasons for discomfort

0 3

shower the ﬂoor

Sometimes humid

Turn lights on

Low ventilation

Change clothes

Yoo Bido

Ofﬁce

Living room

Dining room

-1

Low Illuminance

A/C

Kitchen

Sleeping room

-2

Sometimes hot

2 Terrace

Answers frequency

-3

Answers frequency

Ofﬁce

Living room

Dining room

Sleeping room

Kitchen

Terrace

Sometimes very hot

Answers frequency

-1

-2

-3

Answers frequency

Turn fan on

Answers frequency

Not cozy

Sometimes humid

Low ventilation

Low Illuminance

Sometimes hot

Sometimes very hot

Answers frequency

Operate windows

Take a shower

Turn lights on

Change clothes

A/C

Turn fan on

Operate windows

Answers frequency

280

Answers frequency

4. Results | The Influence of the Vernacular

Monterrey MMA Metropolitan Area Istmo Istmo de Tehuantepec

Spaces where the participants usually spend most of their time in the house

Overall comfort sensation throughout the year

is the relative humidity, which represents the most significant distinction between the climates. The most significant gap stands in between the cities of Garcia in the MMA and Juchitan in the IT. Nevertheless, during the period of the year when the measurements were performed, the values remain usually within the comfort zone. As observed, most of the average values were higher in the IT, which reflect the conditions of discomfort that the inhabitants are subject to. However, the airspeed values were also higher, which significantly contributes to improving the comfort sensation outside and inside of the constructions.

As previously mentioned, apart from the physical outdoor and indoor conditions, the be-

haviour of the users and their usual position in the house significantly contributes to their sensation of comfort. When asking the participants about the spaces where they spend most of the time while being in their house, the answer that appeared the most in the case of the MMA was the terrace (5 times), followed by the kitchen (4 times), the sleeping room and the dining room (3 times each). In the case of the IT, most of the participants included the terrace (7 times) as part of the spaces, followed by the Yoo Bidรณ (4 times) and the living room and dining room (2 times each). The results in both regions show the importance of the outside covered space as part of their everyday life, which is usually used as the space for gatherings. In the IT most of the participants reported that they spend more time outside than inside of the house, which can be explained because of the high indoor temperatures and low levels of natural ventilation. The traditional space Yoo Bidรณ was the favourite indoor space for the users in the only four typologies that still had it. In the MMA, the kitchen was the indoor space that appeared the most, even though it usually is one of the hottest areas in the houses, and therefore one of the most uncomfortable.

When asking the inhabitants about their usual level of activity in those spaces, the an-

swers that appeared in the case of the MMA were sitting/laying down (6 times), standing with low activity (2 times), and standing with mid-activity (1 time). In the IT the answers that appeared were sitting/lying down (8 times), and standing with low activity (1 time). These results show that in most cases the users usually do not produce excessive heat because of their level of activity, which would be a very plausible reason for discomfort. The only difference between both regions is that in the IT the users lay down on hammocks, which appear as part of the furniture in all of the

281

studied houses, and are specially made to allow ventilation. They represent an essential part of the vernacular culture of the region.

The next questions were about their overall comfort satisfaction in those spaces through-

out the year and the reasons for discomfort. In the MMA the answers were: Very comfortable (3 times), comfortable (3 times), slightly comfortable (2 times) and slightly uncomfortable (1 time). The main reasons for discomfort were that the sensation was either hot or too hot (4 times), that there was low illuminance (2 times), low ventilation (2 times), that the space was sometimes humid (1 time), and that it was not cosy (1 time). In the IT the answers for the overall comfort satisfaction of the users were: Very comfortable (5 times), slightly comfortable (1 time), neutral (1 time), uncomfortable (1 time), and very uncomfortable (1 time). The main reason for discomfort was that the sensation was either hot or too hot (4 times), and the feeling of oppression because of low ceilings (1 time). As expected, in both regions the high temperatures generate discomfort; however, a more detailed analysis of the differences between the typologies, which has to do with the, building materials and techniques, is shown in the following section.

4. Results | The Influence of the Vernacular

282

Finally, when asking them what do they adjust when feeling uncomfortable, the answers

in the MMA were: open/close the windows (9 times), turn on the fan (8 times), turn on the air conditioner (5 times), change clothes (4 times), turn light on (1 time), and take a shower (1 time). In the IT the answers were: open/close the windows (7 times), turn on the fan (4 times), change clothes (4 times), water the floor (2 times), and turn on the air conditioner (1 time). These results show first the importance of natural ventilation for the users in both cases, as the most common adjustments are to operate the windows and turn on the fan. In the case of the IT, this is usually the most feasible solution to alleviate the hot sensation; however, in the MMA it is not always the best solution, as sometimes airtightness and thermal mass are needed to avoid heat transfer between the inside and the outside. The results were also closely consistent with the statistics, which show that a higher proportion of houses in the MMA have an air conditioning system (39.8 %) than in the IT (9.4 %), even though the comfort condition in the latter can be considered as worse. A graphical summary of the answers in both regions can be found in figure 184.

4.2.1 RELATION OF RESULTS BETWEEN VERNACULAR AND CONVENTIONAL TYPOLOGIES

As it has been proofed in several research studies (Chandel, Sharma, & Marwah, 2016; Gu-

lati R, 2014; Manríquez et al., 2006), the use of vernacular principles in architecture usually lead to better indoor comfort conditions for the inhabitants, in comparison to cases where such principles are not applied. Vernacular principles belong to a specific region; this is why in this section the results are compared separately for the Monterrey Metropolitan Area and the Istmo region. The intention for this part of the study is to show a comparison of the objective comfort measurements and surveys, but also the point of view of some of the inhabitants towards their perception of comfort in relation to their house.

MONTERREY METROPOLITAN AREA

The results of the measurements of the indoor conditions in the MMA show that in aver-

age there was a better performance in the typologies that were defined as vernacular. A summary of the average indoor values can be seen in table 9, where for example, the indoor air temperature shows only a relatively small difference between the vernacular and conventional cases. Both of them are above comfort values. However, when relating the indoor and outdoor average temperatures (table 10), the difference between the typologies increases. When observing the relative humidity, both cases stay under comfort values, and the difference between exterior and interior is irrelevant. The indoor façade wall surface temperature also stays above comfort levels in both cases; however, the difference of 3 °C between them is considerably high in relation to regular values. The average indoor roof temperature in the vernacular typologies was 35.5 °C, and in the conventional ones, it was 38.0 °C. Some of the outside roof surface temperature values could not be obtained due to accessibility problems, and therefore the difference between temperatures cannot be calculated. The indoor average wind speed was also higher in the vernacular typologies, even when the outdoor values were higher in the conventional cases. Finally, the indoor average illuminance levels stayed within comfort levels in the vernacular cases, while in the conventional

283

the the difference difference of of 3 3 °C °C between between them them is is considerably considerably high high in in relation relation to to regular regular values. values. The average The average indoor indoor roof roof temperature temperature in in the the vernacular vernacular typologies typologies was was 35.5 35.5 °C, °C, and and in in the the conventional conventional could could not not be be

ones, ones, it it was was 38.0 38.0 °C. °C. Some Some of of obtained due to accessibility obtained due to accessibility

the the outside outside roof roof surface surface temperature temperature values values problems, and therefore the difference problems, and therefore the difference bebe-

tween tween temperatures temperatures cannot cannot be be calculated. calculated. The The indoor indoor average average wind wind speed speed was was also also highhigher in in the the vernacular vernacular typologies, typologies, even even when when the the outdoor-recorded outdoor-recorded values values were were higher higher in in er

the cases. Finally, the conventional conventional cases. Finally, the the indoor indoor average average illuminance illuminance levels levels stayed stayed within within comcomtypologies it stayed below. fort levels in the vernacular cases, while in the conventional typologies it stayed below. fort levels in the vernacular cases, while in the conventional typologies it stayed below. Indoor average average values values Indoor Typology Typology Vernacular Vernacular Conventional Conventional

Indoor average values

Air Air temperature temperature 30.1 °C °C 30.1

Relative Relative humidity humidity 41.5 % % 41.5

Wall Wall surface surface temp. temp. 31.0 °C °C 31.0

Wind Wind speed speed 0.29 m/s m/s 0.29

Illuminance Illuminance 139 lux lux 139

31.6 31.6 °C °C

42.7 42.7 % %

34.3 34.3 °C °C

0.14 0.14 m/s m/s

82 82 lux lux

Difference Difference between between indoor indoor and and outdoor outdoor average average values values

Difference between indoor and outdoor average values

Typology Typology Vernacular Vernacular Conventional Conventional

Air Air temperature temperature -3.3 -3.3 °C °C

Relative Relative humidity humidity -0.3 -0.3 % %

Wall Wall surface surface temp. temp. -8.0 -8.0 °C °C

Wind Wind speed speed -0.24 -0.24 m/s m/s

Illuminance Illuminance -1448 -1448 lux lux

-0.6 -0.6 °C °C

-1.5 -1.5 % %

-5.0 -5.0 °C °C

-0.5 -0.5 m/s m/s

-1332 -1332 lux lux

All average values have a standard deviation of CV < 1 unless otherwise indicated

The The temperature temperature difference difference between between the the exterior exterior and and interior interior surfaces surfaces is is an an imimportant parameter to observe in this region because it reflects the thermal resistance and to observe in thisbetween region because it reflects the thermal resistance and portant parameter The temperature difference the exterior and interior surfaces is an important mass of the walls. All of the outer walls of the vernacular typologies were built with highmass of the walls. All of the outer walls of the vernacular typologies were built with highparameter to observe in this adobe, region because it reflects the thermal resistance and mass of the walls. density materials, materials, namely sillar, compressed compressed earth blocks, and massive massive concrete density namely adobe, sillar, earth blocks, and concrete

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blocks, all of with a heat capacity 1000 J/kgºC, thermal All of the walls of the vernacular withand high-density materials, namely blocks, allouter of them them with a typical typical heat typologies capacity of ofwere 1000built J/kgºC, and thermal conductivities conductivities that range from 0.5 to 1.2 W/ m ºC. All the walls from the conventional cases were built that range 0.5 to 1.2 W/ blocks, m ºC. All walls concrete from theblocks, conventional cases were built heat adobe, sillar,from compressed earth andthe massive all of them with a typical with hollow concrete blocks, with a typical heat capacity of 840 J/kgºC, and thermal with hollow concrete blocks, with a typical heat capacity of 840 J/kgºC, and thermal conconcapacity andThe thermal range from 0.5 to 1.2inW/house m ºC.1, Allbuilt the walls ductivityofof of1000 1.2 J/kgºC, W/ m m ºC. ºC. best conductivities measurementthat results were observed ductivity 1.2 W/ The best measurement results were observed in house 1, built with thick blocks, in house 8, with cm both of them from thecm conventional cases wereand built hollow concrete blocks, withwalls; a typical heat with 60 60 cm thick adobe adobe blocks, and inwith house 8, built built with 60 60 cm sillar sillar walls; both of capacity them of with a temperature difference of 11 ºC. Apart from the thermal benefits of those materiwithJ/kgºC, a temperature difference of 11 of ºC.1.2 Apart thebest thermal benefits of thosewere materi840 and thermal conductivity W/ mfrom ºC. The measurement results observed in house 1, built with 60 cm thick adobe blocks, and in house 8, built with 60 cm sillar walls; both

of them with a temperature difference of 11 ºC. Apart from the thermal benefits of those materials, the results of the interviews also show considerable acceptability from the inhabitants. Inhabitant 107 107

2, for example, stated, in relation to compressed earth blocks:

“The house is very comfortable because it is built with a natural material, that is earth, which creates a thermal envelope.”

Inhabitant 5 made a comparison between the houses that were built with sillar, usually

located in the centre of Monterrey, with the “new” houses that are being built on the outsides of the city, referring to the mass produced social housing

Table 9 MMA - Indoor measured average values according to building type Table 10 MMA - Difference between indoor and outdoor average values according to building type

“The houses were much fresher before because they were made out of sillar and they were much larger. The new houses that they are building on the outskirts are rubbish. They are very small, and it seems that they are built out of paper.”

For the average indoor surface temperature of the roofs, the best performance was record-

ed in the houses 4, 7 and 8, where EPS insulation was used. EPS is clearly, not a vernacular material; however, together with the reinforced concrete slabs or beams, it acts as a substitute to the mixture of earth and straw that was used on the roof of the houses during pre-industrial times, adding even thermal resistance to the envelope. Inhabitant 7 made a remark regarding this material:

“Even though the roof is insulated with a material that comes from petroleum, the product itself helps to save energy, and therefore it is good.”

It can also be observed that the average relative humidity had a minimal variation from

the outside to the inside in both cases. That is probably because the measurements were taken during naturally ventilated conditions. Only in the case of Garcia, the out-door and indoor values were relatively low as expected, given the arid climate conditions. However, there were no remarks from the inhabitants regarding this topic. Only inhabitant 9, who lives in the conventional typology in Santiago, reported high indoor humidity as one of the reasons for discomfort.

Other reasons for discomfort that were reported by the inhabitants of the conventional

typologies were: Sometimes very hot (house 6 and 9), low illuminance (house 3 and 6), bad ventilation (house 3), and not cosy (house 3). The overall comfort satisfaction of the inhabitants of the conventional cases was: slightly uncomfortable (house 3), and slightly comfortable (house 6 and 9). When asking them what do they adjust when feeling uncomfortable, the answers were: Operate windows (every house), turn on fan (house 3 and 6), turn on AC only at night (house 6 and 9), turn on lights (house 3), and change clothes (house 6). The overall comfort satisfaction of the inhabitants of the vernacular cases was: very comfortable (house 1, 7 and 8), and comfortable (house 2, 4 and 5). Their reasons for discomfort were reported as: sometimes hot (house 2 and 5), low illuminance (house 2), and low ventilation (house 4). When asking them what do they adjust

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Answers frequency (6 inhabitants)

4. Results | The Influence of the Vernacular

Vernacular typologies Conventional typologies

Predominant materials in exterior walls 5

Overall comfort sensation throughout the year 5

Reasons for discomfort

Fig. 187 Summary of the relation of comfort results between the vernacular and conventional typologies in the

when feeling uncomfortable, the answers were: Operate windows (every house), turn on fan (every house), change clothes (house 4,5 and 8), turn on AC (house 4 and 5), turn on lights (house 2, and 8), and take a shower (house 4).

The results also show that most of the inhabitants in the MMA cases relate the comfort or

discomfort that is experienced in the house with their quality of life. When the inhabitants were asked if the way in which the house was designed has an effect on their quality of life, and if yes, to state the reasons, the answers were correlated or include the words: “comfortable”/“not comfortable”, “Good distribution”, “ambience”, “basic needs”, “garden/nature”, “tranquillity”, “accessibility”, “aesthetics”, “spacious”, “small” and “unhealthy materials”. The number of times these words appeared or were embedded in the answers from the vernacular cases were: comfortable (6 times), garden/nature (3times), good distribution (2 times), tranquillity (1 time), accessibility (1 time) and aesthetics (1 time). An example is the answer of inhabitant 4:

“Yes, the house improves my quality of life. Because of the trees and the interior garden, it is very fresh... Also because of the tranquillity of the neighbourhood.” 287

The number of times these words appeared or were embedded in the answers from the

conventional cases were: comfortable (1 time), uncomfortable (2 times), basic needs (1 time), small (1 time), unhealthy materials (1 time).

ISTMO DE TEHUANTEPEC

The results of the measurements of the indoor conditions in the IT show a better perfor-

mance in the typologies that are defined as vernacular than the conventional. A summary of the average indoor values can be seen in table 11, where for example, the average indoor air temperature shows a difference of 2.7 ºC between typologies, which is a considerably high number when speaking about thermal comfort. However, both values are above the regular comfort zone. The

relation between outdoor and indoor temperatures (table 12), which is a more robust value, also shows a considerably larger value in the vernacular typologies. When observing the indoor relative humidity, both cases are very close to the standard comfort value of 50%, also because the average outside values were close to that number during that time of the year. The average indoor façade wall surface temperature also stays above comfort levels in both cases. When comparing the difference between the outside and inside surface temperatures, the conventional cases had a slightly better performance than the vernacular. The average indoor roof temperature in the vernacular typologies was 32.7 °C, and in the conventional ones, it was 39.7 °C. The indoor average wind speed the vernacular typologies was 32.7 °C, and in the conventional ones, it was 39.7 °C. The the vernacular was 32.7 °C, and Finally, in the conventional ones, illuminance it was 39.7 °C. The was alsoaverage higher typologies in the speed vernacular typologies. the indoor average stayed indoor wind was also higher in the vernacular typologies. Finally, levels the inindoor average wind speed was also higher in the vernacular typologies. Finally, the indoor average levels stayed within levels in the vernacular cases, within comfortilluminance levels in the vernacular cases, whilecomfort in the conventional topologies it stayed below. door average illuminance levels stayed within comfort levels in the vernacular cases, while in the conventional topologies it stayed below. while in the conventional topologies it stayed below.

Indoor average values Indoor average values Typology Typology Vernacular Vernacular Conventional Conventional

Indoor average values

Air temperature Air temperature 32.3 °C 32.3 °C 35.0 °C 35.0 °C

Relative humidity Relative humidity 51.4 % 51.4 % 51.0 % 51.0 %

Wall surface temp. Wall surface temp. 32.2 °C 32.2 °C 34.7 °C 34.7 °C

Wind speed Wind speed 0.43 m/s 0.43 m/s 0.24 m/s 0.24 m/s

Illuminance Illuminance 107 lux 107 lux 78 lux 78 lux

Difference between indoor and outdoor average values Difference between indoor and outdoor average values

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Typology Typology Vernacular Vernacular Conventional Conventional

Difference between indoor and outdoor average values

Air temperature Air temperature -3.3 °C -3.3 °C -0.6 °C -0.6 °C

Relative humidity Relative humidity -2.5 % -2.5 % +0.7 % +0.7 %

Wall surface temp. Wall surface temp. -2.8 °C -2.8 °C -3.1 °C -3.1 °C

Wind speed Wind speed -0.52 m/s -0.52 m/s -0.51 m/s -0.51 m/s

Illuminance Illuminance -1465 lux -1465 lux -1378 lux -1378 lux

All average values have a standard deviation of CV < 1 unless otherwise indicated

As explained in the previous chapter, the materials from the envelope and their thermal As explained in the previous chapter, the materials from the envelope and their thermal mass do not play a significant role in the thermal performance of the constructions. That mass do not play a significant role in the thermal performance of the constructions. That in the relatively low difference between from the exterior and interior can be reflected As explained in the previous chapter, the materials the envelope and theirwall thermal can be reflected in the relatively low difference between the exterior and interior wall surfaces. In fact, the conventional cases, all built with hollow concrete blocks, showed mass do not significant role incases, the thermal performance of the constructions. That can be surfaces. In play fact, athe conventional all built with hollow concrete blocks, showed very similar results than the vernacular cases built with materials like burned bricks, very similar results thanlow thedifference vernacular cases built with materials likewall burned bricks, reflected in the relatively between the exterior and interior surfaces. In fact, adobe, stone and wood and reed. The most significant difference was observed on the adobe, stone and wood and reed. The most significant difference was observed on the roofconventional interior surface, thehollow vernacular cases, built with very several layers (wood, the cases, where all builtall with concrete blocks, showed similar results than the roof interior surface, where all the vernacular cases, built with several layers (wood, earth/concrete, and burned clay tiles), had a considerably better performance than the vernacular cases and builtburned with materials like burned bricks, adobe, better stone and wood and reed. earth/concrete, clay tiles), had a considerably performance thanThe the most conventional cases, built with only one layer (reinforced concrete). The best result for conventional cases, built with onlyonone layer (reinforced concrete). Thethe best result forcases, significant difference was observed interior surface, where vernacular the roof surface temperature (29.0 °C) the wasroof observed in house 14, built all with several layers the roof surface temperature (29.0 °C) was observed in house 14, built with several layers of palm leaves, a significantly lowerand temperature that all the cases. Thebetter built with severalwhich layershad (wood, earth/concrete, burned clay tiles), hadother a considerably of palm leaves, which had a significantly lower temperature that all the other cases. The comfort sensation that the material produced was noted by the interviewee. Apart from performance than the conventional cases, built with onebylayer concrete). The best comfort sensation that the material produced wasonly noted the (reinforced interviewee. Apart from the wooden/palm construction, the house had also a room built with concrete hollow the wooden/palm construction, the house had a room built with concrete hollowlayers result the roof surface temperature (29.0 °C) wasalso observed in house 14, built with several blocks.for When comparing both constructions inhabitant 14 stated: blocks. When comparing both constructions inhabitant 14 stated: of palm leaves, which had a significantly lower temperature that all the other cases. The comfort “The palm house is very fresh, and it is better for my health and my son’s health. I like it “The palm house is very fresh, and it is better for my health and my son’s health. I like it more than the concrete house… the concrete house is too hot.” more than concrete house… concrete is too hot.” Table 11 IT the - Indoor measured averagethe values accordinghouse to building type An important factor for comfort inoutdoor this climate the according correct to ventilation of the spaces. between indoor and average is values building type Table 12 IT - Difference An important factor for comfort in this climate is the correct ventilation of the spaces. In this regard, the houses that had better performance were the ones where the openings In this regard, the houses that had better performance were the ones where the openings were mainly oriented north-south. In the vernacular cases, these were houses 10, 16 and were mainly oriented north-south. In the vernacular cases, these were houses 10, 16 and 17. In the conventional cases, it was house 18. However, the best indoor result (0.56 m/s) 17. In the conventional cases, it was house 18. However, the best indoor result (0.56 m/s) was again recorded in house 14, due to the air permeability of its envelope and because was again recorded in house 14, due to the air permeability of its envelope and because the outdoor values were also the highest given its rural context, where the elements that

sensation that the material produced was noted by the interviewee. Apart from the wooden/palm construction, the house had also a room built with concrete hollow blocks. When comparing both constructions inhabitant 14 stated:

“The palm house is very fresh, and it is better for my health and my son’s health. I like it more than the concrete house… the concrete house is too hot.”

An important factor for comfort in this climate is the correct ventilation of the spaces. In

this regard, the houses that had better performance were the ones where the openings were mainly oriented north-south. In the vernacular cases, these were houses 10, 16 and 17. In the conventional cases, it was house 18. However, the best indoor result (0.56 m/s) was again recorded in house 14, due to the air permeability of its envelope and because the outdoor values were also the highest given its rural context, where the elements that can block the wind currents are less than in an urban context. In most of the typologies. Only typology 15 recorded very low average values of air circulation (0.09 m/s). All the other typologies kept indoor values above 0.2 m/s, which are recommended to improve the comfort satisfaction. Most of the inhabitants in this region also reported to spend some time of the day on the terrace/garden, which can be explained because of cultural reasons, but also for reasons related to comfort and ventilation as exemplified by inhabitant 15, who stated:

“I am already used to the heat, but inside of the house the wind doesn’t go through. That’s why I prefer to be outside on the hammock.”

The overall comfort satisfaction of the inhabitants of the vernacular cases was: very com-

fortable (house 10, 13, 14, 16 and 17), and neutral (house 11). The reasons for the discomfort of the inhabitants of house 11 were reported as: sometimes hot and sometimes cold. When asking the inhabitants what do they adjust when feeling uncomfortable, the answers were: Operate windows (house 10, 11, 13, 16 and 17), turn on fan (house 10, 11 and 13), change clothes (house 11 and 16), and water the floor (house 10 and 11). The overall comfort satisfaction of the inhabitants of the conventional cases was: slightly comfortable (house 18), uncomfortable (house 15), and very uncomfortable (house 12). Their reasons for discomfort were reported as: very hot (house 12 and 15),

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4. Results | The Influence of the Vernacular

Vernacular typologies Conventional typologies

Predominant materials in exterior walls 5

Fig. 188 Summary of the relation of comfort results between the vernacular and conventional typologies in the IT.

sometimes hot (house 18), low ventilation (house 15), and low ceilings (house 15 and 18). When asking them what do they adjust when feeling uncomfortable, the answers were: Operate windows (house 15 and 18), turn on the fan (house 15 and 18), turn on AC (house 12), and change clothes (house 15). It can be noted that none of the typologies except for house 12, has a mechanical air conditioning system, which as mentioned by one of the inhabitants is turned on most of the time when the family is in the house:

â&#x20AC;&#x153;The house is very hotâ&#x20AC;Ś The heat makes me grumpy. I have to turn on the AC all the time while we are in the house.â&#x20AC;?

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4.3

QUALITY OF LIFE

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Different studies suggest that quality of life is subject, culture and time dependent, and there-

fore it should be measured and compared within a specific context in relation to a precise period of time. It is assumed that quality of life can vary according to a comparative perception between situation from past and present, from expectations for the future, and from the comparison to others (van Kamp et al., 2003). Some of the existing indexes and indicators for quality of life are based on objective values and statistical data, in which such subjective and contextual relations are generally not considered. Thus, a qualitative approach serves as a complement to the measured values within a given framework. In this part of the study the results of the interviews with the inhabitants, in relation to their house and quality of life, are shown and compared as an addition to the comfort survey results.

It has also been suggested (Sirgy, Phillips, & Rahtz, 2013) that certain variables have a more

significant relationship to a subjectsâ&#x20AC;&#x2122; quality of life, and one of them is the economy. This argument is taken in this research to compare two regions that have had a very different development closely tied to their economy. The MMA is considered a rich region and the IT is considered a poor region. Within each of the case studies the comparison is done between the inhabitants from the low and high socio-eco-

nomic segmentation, in which the typologies were classified. The other variable that was taken, as a factor for comparison, is the subject of this thesis, which is the influence that vernacular building traditions might have over the inhabitants’ quality of life in contrast with conventional ways of construction.

4.3.1 RELATION OF RESULTS BETWEEN INHABITANTS ACCORDING TO SOCIO - ECONOMIC SEGMENTATION

The field research was focused on regions with significant economic contrast in each of

the case studies. In Mexico this contrast is usually measured with the levels of marginalization, which was the indicator used to determine the municipalities and the areas where the typologies were assessed. The typologies were then classified by the housing market segmentation (Softec S.C., 2016). The low socio-economic segmentation refers to the economic, popular, and traditional types, which are characterized for having less than 90 m² of construction area, and normally belong to families with an income of less than 10 minimum wages per day (around 42 USD, as of January 2017). The high socio-economic segmentation corresponds to the middle, residential, and residential-plus types, which are characterized for having more than 90 m² of construction area, and normally belong to families with an income of more than 10 minimum wages per day. The results are presented separately for each of the studied regions.

MONTERREY METROPOLITAN AREA

From the nine studied cases in the MMA, 5 correspond to a high socio-economic segment

and 4 to a low socio-economic segment. From the high socio-economic segment, 3 are located inside of gated communities, 1 is located in the central business district (CBD), and 1 is situated in a rural context. 4 of them correspond to the residential-plus sector, and 1 to the residential sector. From those cases, 3 were self-commissioned, and built by architects, and 2 were built by

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developers. From the low socio-economic segment, 2 are located in the CBD, 1 is located in the suburbs, and 1 is situated in a rural context. 3 of them correspond to the traditional sector, and 1 to the popular sector. From those cases 3 houses were self-built and 1 house (house 3) was built by developers but extended and renovated by the owner. These results reflect a typical situation in the MMA. Architects are hired by high socio-economic classes, and sometimes by developers. Most of the houses from the low socio-economic levels are either self-built or part of a mass-constructed social development.

From the high socio-economic segmentation, the average construction area was 241.0 m2

(s = 66.9) and the average occupation was 3 (s = 0.7) inhabitants per household with an average of 80.4 m2 (s = 13.8) per person; the average terrace area was 126.3 m2 (s = 108.6), and the average garden area was 1,774.0 m2 (s = 3,483.3). From the low socio-economic segmentation, the average construction area was 75.3 m2 (s = 18.9) and the average occupation was 3.75 (s = 2.4) inhabitants per household with an average of 25.4 m2 (s = 14.9) per person; the average terrace area was 19.1 m2 (s = 13.8), and the average garden area was 850.25 m2 (s = 1,438.6). Nevertheless, the average garden area is not representative as the cases from the rural context significantly increase

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the standard deviation (s). The result that better shows the disparity that exists between the socio-economic segments between the selected houses is the average area per person. This discrepancy is even more dramatic when taking the extreme cases, which are 104.8 m2 (house 1), and 8.8 m2 (house 2) per person.

What means quality of life to you?

To understand if there is a conscious relation between the built environments to the qual-

ity of life of the inhabitants, the approach was first to ask the meaning that they give to the term quality of life. The concepts that were given have been grouped into the following terms: “well-being”, “health”, “comfort”, “tranquillity”, “needs”, “security”, “free time”, “Business”, “financial solvency”, and “nature”. The concepts that appeared or were embedded in the answers from the high socio-economic segment were: needs (3 times), well-being (2 times), tranquillity (2 times), security (2 times), comfort (2 times), health (1 time), free time (1 time), business (1 time), and nature (1 time). The concepts that appeared or were embedded in the answers from the low socio-econom-

ic segment were: needs (2 times), well-being (2 times), tranquillity (2 times), comfort (2 times), health (1 time), and financial solvency (1 time).

It can be observed that the only term that was not included in the answers from the high

socio-economic segment was “financial solvency”, and within the low socio-economic segment the concepts that were not included are “security”, “free time” “business” and “nature”. The results also show that the concepts that are shared between the two groups are: “needs”, “well-being”, “tranquillity”, “comfort”, and “health”. There are slight differences in how the interviewees perceived those concepts; however, most of the answers were relatively short, and both groups used similar words to define what quality of life meant to them.

For example, the “needs”, which was the most frequent concept, can significantly vary

from person to person, and following Maslow’s principles, they can range from basic physiological needs to complex self-actualization needs, and could include almost all of the given answers. According to Hagerty (1999), meeting Maslow’s proposed needs is the path to a good quality of life, but reaching all needs is dependant on the level of economic welfare. Therefore, for this group, only answers that made a direct reference to the word “needs” or basic physiological needs were comprised. For the high socio-economic segments, the answers included: “having everything that you like and according to your needs” (inhabitant 4), “meeting all the basic needs like walking, eating, and sleeping” (inhabitant 6), and “having everything you need” (inhabitant 9). For the high socio-economic segments the answers included: “eating, resting, and having everything you need” (inhabitant 3), and “that the house has everything you need, and that it has big spaces” (inhabitant 8). All answers shared similarities and referred to the subject but the last one, which was referred to material possession, the house.

Another complex concept, which can encompass different meanings, is “well-being”. De-

pending on the source, it can be used as a synonym or confused with comfort. However well-being is commonly related to happiness, and positive experiences or ideas, while comfort refers more to a physiological sensation in relation to the physical environment. In many studies health is also considered to be part of well-being (Pinto, Fumincelli, Mazzo, Caldeira, & Martins, 2017). In this context “well being” was used for similar answers regardless the socio-economic position (inhab-

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Health

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4. Results | The Influence of the Vernacular

High socio-economic segment Low socio-economic segment

Construction area per person

What means quality of life to you? 5

Which aspects of your neighbourhood have an effect on your quality of life?

Fig. 189 Summary of the relation of quality of life results according to socio-economic segmentation in the MMA.

itants 3, 4, 6, and 8), which included: “to feel good” “to live well”, and “to be pleased”. The concept comfort was also used similarly by both groups (inhabitants 1, 2, and 4) with answers that included the term, like “being comfortable” or “feeling comfortable”. Finally, the concept “health” appeared 1 time in both groups (inhabitants 5 and 9), both referring to “being healthy” as an essential part of life quality.

Which aspects of your neighbourhood have an effect on your quality of life?

The second open question that was asked to the inhabitants was focused on a more di-

rect relation between quality of life situated in a specific context. The answers were also grouped into concepts, which included “security”, “insecurity”, “car dependence”, “green areas”, “distance to services”, “busy neighbourhood”, “calmed neighbourhood”, and “lack of water”. For the high socio-economic segment, the order of the concepts according to frequency was: security (3 times), car dependence (3 times), far from services (2 times), insecurity (1 time), green areas (1 time), busy neighbourhood (1 time). For the low socio-economic segment the frequency of the concepts was: Insecurity (3 times), car dependence (2 times), busy neighbourhood (2 times), far from services (1 time), close to services (1 time), calmed neighbourhood (1 time), and lack of water (1 time).

It can be noted that for these results there is a more significant difference between the

groups according to socio-economic segmentation. Concepts related to security were the most common among the answers from both groups; however, in the high socio-economic segment there are more answers (inhabitants 4, 6, and 9) with a positive connotation, describing it as: ”a very safe neighbourhood”, and “it is safe”. These inhabitants are precisely the ones that live within gated communities. The inhabitant from house 7, which is in a rural context, included “it (the quality of life) is affected by insecurity” in his answer. The three answers from the low socio-economic sector (inhabitants 3, 5, and 8) had a negative connotation with the answers: “the insecurity”, and “it is not safe”. The first case is located in the suburbs and the other two cases within the CBD.

Other concepts that are correlated and that were important for both of the groups were:

“car dependence”, and “distance to services”. Regardless of the socio-economic sector, the de-

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pendence on the car had a negative connotation (inhabitants 1, 2, 3, 7, and 9), which was related directly to being far from the city or from the services (inhabitants 3, 7, and 9). The cases correspond to locations in the suburbs, the rural context, and a gated community respectively. An example is the answer from inhabitant 3:

“What affects me the most is that everything is far away, and I have to use the car for everything.”

Only one of the inhabitants (inhabitant 5), who lived in the CBD of Monterrey, gave a pos-

itive answer regarding the location of the house in relation to the “distance to services”. However, he also associated it with a negative connotation related to a “busy neighbourhood”, the same as inhabitant 1, and inhabitant 8, that had a similar reaction concerning the visitors in the centre of Garcia and Santiago respectively. As an example the answer from inhabitant 5 was:

“it is good because everything is close. Everything is within walking distance. The bad thing is that lately there are a lot of people coming. It was better before, more calmed.”

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ISTMO DE TEHUANTEPEC

From the nine studied cases in the IT, 6 correspond to a high socio-economic segment and

3 to a low socio-economic segment. From the high socio-economic segment, all of the cases are located in the central areas of the cities. 4 of them correspond to the middle sector, and 2 to the residential sector. From those cases 4 were self-commissioned, and built by architects, and 2 were self-built. From the low socio-economic segment 2 are located in central areas of the cities, which correspond to the traditional sector, and 1 is located in a more rural context and corresponds to the economic sector. All of those houses were self-built. In this region, there are almost no houses built by developers, so there is a low percentage of the population that can commission their homes, and the rest are self-built.

From the high socio-economic segmentation, the average construction area was 112.5 m2 (s = 23.5) and the average occupation was 2.7 (s = 0.5) inhabitants per household with an average of 42.3 m2 (s = 3.9) per person; the average terrace area was 47.1 m2 (s = 53.6), and the average garden area was 171.7 m2 (s = 157.1). From the low socio-economic segmentation, the average construction area was 59.6 m2 (s = 19.6) and the average occupation was 3.7 (s = 0.9) inhabitants per household with an average of 26.2 m2 (s = 17.5) per person; the average terrace area was 26.2 m2 (s = 17.5), and the average garden area was 177.2 m2 (s = 68.3). In contrast with the MMA, in this region, the differentiation between socio-economic classes is not so notorious, which is reflected in the size of the houses, and apart from the slums, in the relatively equal distribution of the urban space. The construction area per person also has less discrepancy than in the MMA, even when taking the extreme cases, which are 45.3 m2 (house 12) and 12.3 m2 (house 14) per person

What means quality of life to you?

The same questions were asked to the inhabitants of the houses in the IT The concepts

that were given have been grouped into the following terms: “needs” “well-being”, “health”, “comfort”, “tranquillity”, “stability”, “financial solvency”, “family”, and “happiness”. The concepts that appeared or were part from the answers from the high socio-economic segment were: needs (4 times), well-being (3 times), health (2 times), comfort (2 times), stability (1 time), and financial solvency (1 time). The concepts that appeared or were embedded in the answers from the low socio-economic segment were: needs (2 times), family (2 times), comfort (1 time), health (1 time), tranquillity (1 time), well-being (1 time), and happiness (1 time).

Most of the answers were very similar to the ones given by the inhabitants in the MMA.

Most of the terms that were shared by both groups in the IT also signify the most representative factors in this region according to their frequency of appearance, which are “needs”, “well-being”, “health”, and “comfort”. Most of the answers to refer to those concepts were also very similar, with short expressions or sentences like “to feel good”, “to meet the basic needs”, “being healthy”, and “being comfortable” among others. Examples of more elaborated answers regarding those concepts were given by inhabitant 13 and 16:

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by author 1

0 Happiness

Health

Comfort

Calmed neighbourhood

More than 100 m2

81 - 100 m2

61 - 80 m2

0 41 - 60 m2

Family

21 - 40 m2

Tranquility

Less than 20 m2

Number of houses (4 houses)

Wellbeing

Needs

Answers frequency (4 inhabitants)

More than 100 m2

81 - 100 m2

61 - 80 m2

41 - 60 m2

21 - 40 m2

Less than 20 m2

Number of houses (5 houses)

Neighbours

Answers frequency (4 inhabitants)

Financial solvency

Stability

Health

Answers frequency (5 inhabitants)

Security

TrafďŹ c

Comfort

Gatherings

Calmed neighbourhood

Close to services

Neighbours

Comfort

Wellbeing

Needs

300

Insecurity

Security

Answers frequency (5 inhabitants)

4. Results | The Influence of the Vernacular

High socio-economic segment Low socio-economic segment

Construction area per person

What means quality of life to you? 5

Which aspects of your neighbourhood have an effect on your quality of life?

Fig. 190 Summary of the relation of quality of life results according to socio-economic segmentation in the IT. Made

“Quality of life is first to satisfy your basic needs, to be in good health and physical condition, and finally to maintain a good mental state.”

“It is to have well-being and to satisfy your physical, somatic, physiological, psychological, ontological and psychic needs.”

Another result to be noted is the different concepts that appeared in this region within the

low socio-economic segment, which were “family”, and “happiness”. Family was the only concept associated directly with a social relation, even if it is implicit in some of the other concepts. It appeared as part of the answers of inhabitants 11 and 17:

“It is to be comfortable, to be fresh, and to be good in the house and with my family”

“Quality of life is to be happy, and enjoying what one has together with the family”

The term happiness is usually associated in scientific literature to well-being (Pinto et al.,

2017), and it is subject to a question that has been posted in several studies: Will greater wealth produce greater happiness? (Diener & Suh, 2003). This question even if it is not the focus, it is inherent to this research, but in relation to quality of life.

Which aspects of your neighbourhood have an effect on your quality of life?

The answers for the second question were grouped into the following concepts “securi-

ty”, “insecurity”, “distance to services”, “busy neighbourhood”, “calmed neighbourhood”, “neighbours”, “gatherings”, “comfort” and “traffic”. For the high socio-economic segment, the order of the concepts by frequency was: security (3 times), neighbours (3 times), close to services (2 times), gatherings (2 times), insecurity (1 time), calmed neighbourhood (1 time), comfort (1 time), and traffic (1 time). For the low socio-economic segment the frequency of the concepts was: Neighbours (3 times), Security (2 times), calmed neighbourhood (1 time).

The answers in the IT had also similarities to the ones from the MMA, and they were

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also similar between the high and low socio-economic segments. “Neighbours” was the term that appeared the most within the two groups. It can be noted that it is also a concept that is directly connected to social relations, and that did not appear in the answers from the MMA inhabitants. However, the concept had different connotations depending on the inhabitant. For 4 of them, the relationship with the neighbours had a positive effect on their quality of life. Their answers included “the interaction with the neighbours is good” (inhabitant 17), “the neighbours are friendly” (inhabitant 16), and “the neighbours are there when something is needed” (inhabitant 18). Inhabitant 13 gave a more complex answer, which also involved the concept of “comfort”, “security”, and “gatherings”:

“Safety is very important. Juchitan is not safe, but this area is safer. That is why we keep a good relationship with the neighbours that we trust. For that reason, we normally gather in the houses… and the climate is normally pleasing for the gatherings.”

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For two of the inhabitants the relation with the neighbours has an adverse effect over

their life quality, as stated by inhabitant 11 and 14:

“The neighbourhood is calmed, but the interaction with the neighbours is difficult.”

“I don’t like the people from the community because they are always divided by politics.”

Security was also an important aspect for both of the groups. In contrast with the answers

from the inhabitants of the MMA, most of the responses in this region regarding that concept had a positive connotation.

4.3.2

RELATION OF RESULTS BETWEEN INHABITANTS ACCORDING TO VERNACULAR AND CONVENTIONAL TYPOLOGIES

As previously mentioned, studies comparing vernacular and conventional constructions

are often focused on objective variables related to comfort. However, there are other benefits and disadvantages of using certain building techniques, materials, forms, and spatial distributions, which are related to the users’ perception concerning their quality of life. In this section, the results are shown for the third answer that was asked to the inhabitants in both of the case studies, which is a direct association between their immediate physical environment, namely their house and its effects on their quality of life. The question that was posted, which is divided into two part is:

“Do you think that the way in which your house is designed and built has an effect on your quality of life? In what sense”?

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MONTERREY METROPOLITAN AREA

The answers of the inhabitants from the cases in the MMA were correlated or include the

concepts: “comfortable”, “not comfortable”, “distribution”, “ambience”, “needs”, “courtyard/garden”, “tranquillity”, “accessibility”, “aesthetics”, “size”, and “building materials”. The order of the concepts by frequency of appearance in the answers from the vernacular cases was: comfortable (5 times), courtyard/garden (3 times), building materials (2 times), size (2 times), tranquillity (2 times), ambience (1 time), accessibility (1 time) and distribution (1 time). In the conventional cases the order of the concepts by frequency was: uncomfortable (2 times), size (2 time), needs (1 time), comfortable (1 time), building materials (1 time), accessibility (1 time).

The results show that most of the inhabitants in the MMA cases relate the comfort or

discomfort that is experienced in the house with their quality of life. In five of the vernacular cases and in one of the conventional cases, the inhabitants made a positive reference to the concept of comfort. The most common word that was used by the inhabitants to express such sensation was “fresh”. It appeared as a description of the house (inhabitants 2, and 6), in relation to the building materials (inhabitants 1, and 5) and as a relation to the courtyard and the natural surroundings (inhabitants 1 and 4). The answer of inhabitant 1 also included concepts related to the size and the general ambience as essential aspects:

“Yes, it has an effect in every sense. First of all because of the spaciousness and the energy that can be felt. Also because it is built with very thick adobe walls it is very fresh. Also because of the interior courtyard that gives peace and tranquillity.

In one of the conventional cases (Inhabitant 3), the reference to the size, the building ma-

terials, and comfort, appeared with a negative connotation in relation to the quality of life of the inhabitant. She stated:

“Yes, it sometimes affects it, because it is small. I would prefer to have one more

4. Results | The Influence of the Vernacular

304

room. It is also very hot inside, so I prefer to be outside most of the time. Also, the materials that they used (the developers) affect health ”

A concept that appeared in both groups (inhabitants 6 and 7), which is not directly related

to comfort is accessibility. In both of the cases, the interviewees were older than 65 years, so the mobility inside of the house was directly linked to their life quality. The answer of inhabitant 6 also included the concepts of size and comfort as part of her answer:

“Yes, because the house is spacious, but I don’t have to go up the stairs to go to my room. Also because the house is fresh”

text:

Inhabitant 7 also included concepts related to the distribution and to the natural con-

“Yes, because it was designed according to my age. It is functional because it was built only on one floor… The architecture is important for life quality, but also the (natural) surroundings.”

A graphical summary of the frequency of the concepts in this section is presented in figure

189, together with the results from the IT.

ISTMO DE TEHUANTEPEC

When the inhabitants were asked if the way in which the house was designed and built

has an effect on their quality of life, and if yes, to state the reasons, the answers were correlated or included the concepts: “comfortable”, “not comfortable”, “ambience”, “well-being”, “spacious”, “small”, “height”, “needs”, “family”, and “building materials”. According to frequency, the concepts that appeared or were embedded in the answers from the vernacular cases were: comfortable (6 times), building materials (2 times), well-being (2 times), needs (2 times), and ambience (1 time). The order in which the concepts appeared in the answers from the conventional cases was: uncomfortable (2 times), height (2 times), size (2 times), building materials (1 time), needs (1 time), and family (1 time).

The results in the IT also show, as it was the case in the MMA, that most of the inhabitants

relate the comfort or discomfort that is experienced in the house with their quality of life. In all of the vernacular cases, the effect was positive in relation to comfort. In 3 of the cases, the sensation was also associated with the word “fresh” and in the other 3 cases the house was described as “comfortable”, or “very comfortable”. In the case of inhabitant 13, his answer was also complemented with the concept of materials and ambience in relation to well-being:

“Yes, the space is very fresh and the materials and the way the interior is designed help me feel fine.”

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Monterrey Metropolitan Area Conventional typologies

Vernacular typologies

5 Answers frequency (3 inhabitants)

4 3 2 1

2 1 Accesibility

Needs

Size

Building materials

Comfortable

Distribution

Accesibility

Ambience

Tranquility

Size

Building materials

Comfortable

306

Istmo de Tehuantepec Conventional typologies

Vernacular typologies

Do you think that the way in which your house is designed and built has an effect on your quality of life? 6

5 Answers frequency (3 inhabitants)

4 3 2 1

3 2 1 Family

Needs

Size

Building materials

Height

Ambience

Needs

Wellbeing

Building materials

0 Comfortable

Uncomfortable

Answers frequency (6 inhabitants)

4. Results | The Influence of the Vernacular

0 Courtyard/garden

Uncomfortable

Answers frequency (6 inhabitants)

Do you think that the way in which your house is designed and built has an effect on your quality of life?

Fig. 191 Summary of the relation of quality of life results between vernacular and conventional typologies in the MMA and the IT. Made by author

In two of the conventional cases (inhabitant 12 and 18) the feeling of discomfort was

directly related to the height of the ceiling. An example is inhabitant 18, who even though gave a positive connotation to the size of the space, also had a negative sensation associated with the temperature, which at the same time she linked with the low height:

“Yes, I like that the spaces are big. However, it sometimes affects it because it is too hot. I think it is because the ceilings are too low. I would prefer them higher.”

Another concept that appeared in both groups (inhabitants 11, 15, and 17), and which

was an important factor when defining quality of life during the first question, is “needs”. For both inhabitants 11 and 17 the concept was defined shortly as “meets the basics” and “it has enough, the necessary”. However, inhabitant 15 added another concept related to size and in relation to his family:

“Yes, my house has the basics, but I think it should be bigger, because I have a lot of sons, and I would like to host them all when they come to visit.” 307

4.4

SUSTAINABILITY

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308

As previously mentioned in the study on building material preference (section 2.4), the exist-

ing research is extensive concerning the relation between sustainability and vernacular architecture; however, studies on the usersâ&#x20AC;&#x2122; cognition towards the subject are usually not contemplated. The conclusions from the results of that preliminary study suggest that there might be a lack of information regarding low-energy and carbon emissions in the general population in the country, which are subjects directly related to environmental sustainability. Such information is essential when reflected in the high percentage of self-construction and potential decision-makers within the general population. Another preliminary conclusion was that environmental awareness is directly related to the economic level of the population (Rohracher & Ornetzeder, 2002). That is why; the last question that was asked to the inhabitants was posted as a follow-up to that preliminary study on the quest to understand the position of the users towards sustainability.

Moreover, sustainability as a concept goes far beyond the environmental factors. As previously

suggested in this research or by citing the words of Marcel Vellinga (2015):

A large extent also depends on other, social, cultural, and economic factors. Indeed, these factors may be much more crucial. The cost of labor, the availability of resources, the social needs and aspirations of the owners, the cultural values associated with materials and technologies; all those aspects play an equally important role in determining whether a form of architecture is sustainable or not.

Thus, the intention was also to investigate if any of those factors are also part of the users’

cognition in relation to the concept. It is also to assess the different points of view of the inhabitants regarding their economic positions and according to their context; therefore, the results to this question are presented separately for the MMA and the IT. The question was:

What means sustainable architecture to you?

MONTERREY METROPOLITAN AREA

The answers of the inhabitants from each of the selected samples in the MMA were also

grouped into concepts, which included: “natural materials”, “traditional architecture”, “self-production”, “natural resources”, “economic value”, “energy savings”, “construction quality”, and “quality of life”. One of the inhabitants did not know the concept. The order of the concepts by frequency of appearance in the answers from the high socio-economic segment was: natural materials (3 times), economic value (2 times), natural resources (2 times), traditional architecture (1 time), self-production (1 time), energy production (1 time), and does not know (1 time). For the inhabitants living in the houses classified as low socio-economic segment, the order of the concepts by frequency was: economic value (2 times), energy savings (1 time), natural materials (1 time), construction quality (1 time), quality of life (1 time), and traditional architecture (1 time).

The only concept that was repeated two times in both of the groups was “economic value”.

However, it was observed differently in both groups. Both of the inhabitants from the high socio-economic sector, perceived it as something achievable. Inhabitant 1, for example, referred it to traditional building techniques and to natural materials, which can be considered “low tech” and

309

are from his point of view not expensive:

“It is architecture that can be done with local materials like adobe. Like it was done in traditional architecture. So, sustainability is not expensive as people think.”

Inhabitant 4, on the other hand, perceived it as expensive but necessary:

“It is excellent when you can apply sustainability in architecture. It is expensive, but necessary to be able to conserve the resources of the planet.”

Both cases from the low socio-economic segment described it as something difficult to

get. Inhabitant 8, for example, related it also to traditional architecture:

“I think architecture was more sustainable before, because of the materials they used, and they also used less energy. For this house we tried to get sillar to build the extension, but it is very difficult to find it in the region and very expensive.”

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310

Inhabitant 3, described it also as expensive, but she was the only interviewee in the MMA

who related it to the concept of quality of life:

“It is architecture that has all the means to be able to live better, but it is very expensive.”

The other important concept, which was the most frequent among the high socio-eco-

nomic segment, is natural materials. Apart from the before mentioned answers where it was included, the answer from inhabitant 7 demonstrated a high level of knowledge regarding the concept in relation to environmental factors:

“Sustainable architecture is achieved when you are able to self-maintain the house and its inhabitants. For example, in this house, this is done by carrying water from

the stream with hammer pumps. Also with the self-production of food with the aquaponics systems. Apart from that the house is built with natural materials, and I produce my own electricity with solar panels.”

A graphical summary of the frequency of the concepts in this section is presented in figure

190, together with the results from the IT.

ISTMO DE TEHUANTEPEC

The answers from the inhabitants in the IT were grouped into the following concepts:

“natural materials”, “self-production”, “future generations”, “natural resources”, “construction quality”, and “quality of life”. There were also 3 inhabitants that did not know the concept. The order of the concepts by frequency of appearance in the answers from the high socio-economic segment was: natural resources (3 times), does not know (2 times), self-production (1 time), natural materials (1 time), and future generations (1 time). For the inhabitants living in the houses classified as low socio-economic segment, the order of the concepts by frequency was: natural resources (1 time), future generations (1 time), natural materials (1 time), construction quality (1 time), quality of life (1 time), and does not know (1 time).

In this region, the only concept that appeared more than one time was “natural resourc-

es”. The relation to this concept was perceived in different ways and served as a relation to other concepts, such as “next generations”, which was the only concept introduced different from the ones that were also used in the MMA. There was no noticeable differentiation in the use of the concept between the two groups. For example, inhabitant 11 stated:

“Sustainable architecture is when you can take advantage of the natural resources and you can maintain them so that they can also be used by our children and the next generations”

And the answer from inhabitant 13 was:

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and the IT. Made by author 2

Does not know

Quality of life

Construction quality

High socio-economic segment Does not know

Quality of life

Construction quality

Traditional architecture

Future generations

Energy savings

Economic value

Natural materials

Answers frequency (4 inhabitants)

Natural materials

Answers frequency (3 inhabitants)

312 Does not know

Energy production

Self-production

Traditional architecture

Natural resources

Economic value

Natural materials

Answers frequency (5 inhabitants)

High socio-economic segment

Natural resources

Does not know

Future generations

Self-production

Natural materials

Natural resources

Answers frequency (6 inhabitants)

4. Results | The Influence of the Vernacular

Monterrey Metropolitan Area Low socio-economic segment

What means sustainable architecture to you?

Istmo de Tehuantepec

Low socio-economic segment

What means sustainable architecture to you?

Fig. 192 Summary of the relation of sustainability results according to socio-economic segmentation in the MMA

“It is architecture in which there is a careful and conscious use of natural resources. The resources are going to be finished, so it also implies the reuse of resources, so that there are still enough for the future generations.”

The concept of quality of life was related by one of the inhabitants (inhabitant 17) in this

region, who also included the quality of the construction in the answer:

“Sustainability is good in architecture because it helps to improve the quality of the building materials and the quality of life of the inhabitants of the house”

It can be noted, as it was the case in the MMA that there were more inhabitants from the

houses classified as high socio-economic segment that reported not to know the concept than there were in the low socio-economic segment.

313

4.5

THE FINDINGS

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314

The field study represented the most important part of this dissertation in the quest to answer

the main research question. In general, it can be stated that the results of the study reflected the expectations in both of the case studies when comparing the vernacular with the conventional cases. In overall, the houses with vernacular characteristics had better thermal performance and greater acceptance from the inhabitants. However, the results from the measurements do not show a significant difference between the cases, which could be explained by the occupantsâ&#x20AC;&#x2122; behavior and the way they respond to the exterior climate. Another unexpected finding is that when comparing the inhabitants from the high and low socio-economic segments, there were some discrepancies with previous studies and the preliminary findings also in both cases. More significant differentiation between both groups was expected; nevertheless, their answers and treated concepts remained similar in most of the questions. In the following sections, a summary of the results is displayed for each of the case studies. The main findings are presented separately, given the different contextual background of both regions, but a mutual conclusion is also done to display the differences and similarities between them and their relation to the national context.

MONTERREY METROPOLITAN AREA

The results for the MMA showed that the construction materials played a primordial role

on the interior thermal performance of the studied houses. Also, they have a major impact on the positive or negative sensation expressed by the inhabitant towards their overall comfort satisfaction throughout the year. The materials that were mainly used on the envelope of the typologies defined as vernacular were sillar, adobe and CEB, which have a high density, contributing to a relatively high thermal mass and resistance. Given the semi-arid climate with high temperature variations, those characteristics are essential to delay the heat transmittance between the inside and the outside. Therefore, the difference between their interior and exterior surface temperatures, as observed in table 13, was higher than in the cases defined as conventional, which were mainly built with cement-based materials, namely concrete hollow blocks. The table shows a summary of the results, where the best values for each measurement correspond mainly to the vernacular typologies. However, in all of the houses, the interior temperatures remained above comfort values.

Summary of measurements

315

In Air T

Air T Δ

In wall surf. T

Wall surf. T Δ

In roof surf. T

In wind speed

In Illuminance

House 1

28.9 °C

4.5 °C

31.0 °C

11.0 °C

37.0 °C

0.26

House 2

31.2 °C

2.4 °C

30.0 °C

7.0 °C

38.0 °C

0.22

House 3

32.0 °C

1.1 °C

35.0 °C

2.0 °C

38.0 °C

0.25

House 4

31.4 °C

3.9 °C

32.0 °C

5.0 °C

33.0 °C

0.2

380

House 5

29.4 °C

3.0 °C

33.0 °C

9.0 °C

37.0 °C

0.35

300

House 6

31.5 °C

0.7 °C

36.0 °C

6.0 °C

38.0 °C

0.12

150

House 7

29.8 °C

2.5 °C

30.0 °C

5.0 °C

34.0 °C

0.6

House 8

29.6 °C

3.2 °C

30.0 °C

11.0 °C

34.0 °C

0.12

House 9

31.2 °C

1.1 °C

32.0 °C

7.0 °C

38.0 °C

0.08

Vernacular typologies In Air T

Air T Δ

In wall surf. T

Wall surf. T Δ

In roof surf. T

In wind speed

In Illuminance

Conventional typologies House 10 32.2 °C

5.3 °C

34.0 °C

4.0 °C

34.0 °C

0.48

House 11

32.5 °C

4.0 °C

34.0 °C

3.0 °C

35.0 °C

0.28

House 12

34.6 °C

1.7 °C

34.0 °C

4.0 °C

40.0 °C

0.26

3.1 °Cmeasured 32.0cases °C 1.0 °C °C 0.35 40 House 13 The 31.2 best°Cof the nine concerning indoor32.0 comfort in the MMA was house 1,

House 14

31.9 °C

0.7 °C

29.0 °C

3.0 °C

29.0 °C

0.56

300

which is also depicted in table 13. This house showed a better performance in the air and wall temHouse 15 36.0 °C -0.2 °C 34.0 °C 37.0 °C 0.09 35 5.0 °C

House 16 34.5 °C between 2.3 °Coutside 33.0 2.0 °C 34.0 °C 0.46 indoor climate. 45 perature difference and°Cinside and therefore achieving a colder House 17

31.2 °C

4.6 °C

31.0 °C

4.0 °C

32.0 °C

0.48

This adapts to °C the outdoor conditions3.0due design0.38 strategies that House house 18 34.5 °C better 0.3 36.0 °C °C to the passive 42.0 °C 130 were used in its construction, which include:

Table 13 Summary of measurements in the MMA

1. Orientation - The house runs along the east-west axis, therefore minimizing sun exposure in walls and openings during summer. 2. Thermal mass - The house is built primarily with adobe 60 cm thick walls, and massive concrete roof, which have a high density and thermal capacity. Thus, it can balance the temperature fluctuations between day and night. 3. Openings - There is a small area proportion of the windows and doors that face the exterior, and even though they do not have glass, they are protected with thick wooden shutters and doors. 4. Configuration - The courtyard is used as a passive cooling strategy as it maintains a cooler micro-climate than the street. The loggia further enhances the conditions by protecting the interior faรงade from the sun. 5. Space distribution - The single-room linear distribution with a U-shape allows crossed-ventilation when it is needed (in summer mainly throughout the night). 6. Height - The warmer air remains up due to the high ceiling with almost 5m. It also keeps the radiant heat transmitted through the roof farther away from the inhabitants.

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316

Fig. 193 Axonometric view of house 1

Another important aspect that contributed to the good performance of the house was the

occupants’ behaviour. The way in which the inhabitants use the space and the way they operate the different components of the house (windows, shutters, and mechanical systems) can have a significant impact on their thermal comfort and the energy demand of the building (Haldi & Robinson, 2011). In the case of the MMA the inhabitants should try to avoid heat gains in the interior of the house during summer. A common mistake that was perceived in the vernacular and conventional cases without an air conditioning system was the opening of windows during the day to ventilate the house. As it is an arid climate the air movement does not contribute considerably to the comfort sensation. Therefore the recommended strategies, which were also mainly followed by the inhabitants of house 1, as stated in the comfort survey, include:

1. Openings - The windows and doors should remain open during the night or when the outdoor temperature drops below 24ºC, and no cooling system is in operation. If the indoor temperature is already below that value, the openings should remain closed during the day, when the outdoor temperatures are higher. 2. Shutters - Outdoor shutters can prevent solar heat gains and should be kept closed during summer when there is direct sun exposure. 3. Indoor activity – Indoor physical activities, artificial lights, or any other action that produce heat should be minimized during the day. Cooking should be done preferably in a separate or isolated room, as in the case of house 1. 4. Fan – it can be used as a ventilation measure when there is high humidity during summer. 5. Cooling systems – They can be used for a short period if the indoor temperatures rise, but after the temperature drops below 24ºC, the other steps can be followed.

Even though most of the measured values were above comfort levels as illustrated in table

13, the sensation of “freshness” was reported by 5 of the 6 inhabitants of the vernacular cases who experienced in general comfortable conditions. The positive assessment was mainly attributed to the building materials and the house configuration. The inhabitants of the conventional cases reported mostly uncomfortable overall conditions related mainly to the building materials, the hot indoor temperature, and the size of the spaces. It can be noticed in the results of the interviews that there is a general preconception about the vernacular way of building, which is regularly seen

317

as more comfortable. That could explain the relatively significant difference between the measured values and the overall sensation of the inhabitants, who could be biased by their previous beliefs.

Another representative variable that was compared is the disparity between the high and

low socio-economic segments. The results show that in the MMA the construction and terrace area, and therefore, the area per person, represented the most significant difference between both groups. The most notorious being house 1 and house 2 with 104.8 and 8.8 m2 per person respectively, as it can be observed in table 14. As mentioned before, the size of the house is an essential measure of social status in the region, which was also reflected in the selected examples.

Summary of areas

4. Results | The Influence of the Vernacular

318

Segmentation

Inhabitants

m2 house

m2 terrace

m2 garden

m2/person

House 1

Residential-plus

314.4 m2

315.2 m2

355.7 m2

104.8 m2

House 2

Traditional

70.5 m2

32.4 m2

3000.0 m2

8.8 m2

House 3

Popular

50.5 m2

9.6 m2

38.0 m2

25.3 m2

House 4

Residential-plus

213.4 m2

115.8 m2

385.6 m2

71.1 m2

House 5

Traditional

90.0 m2

0.0 m2

53.0 m2

45.0 m2

House 6

Residential-plus

228.7 m2

46.2 m2

47.5 m2

76.2 m2

House 7

Residential

150.0 m2

84.9 m2

8000.0 m2

75.0 m2

House 8

Traditional

90.0 m2

34.4 m2

310.0 m2

22.5 m2

House 9

Residential-plus

298.7 m2

69.4 m2

85.9 m2

74.7 m2

Inhabitants

m2 house

m2 terrace

m2 garden

m2/person

High socio-economic segmentation Segmentation Low socio-economic segmentation

House 10

Middle

132.0 m2

151.1 m2

42.5 m2

44.0 m2

House 11

Traditional

71.4 m2

42.7 m2

161.2 m2

14.3 m2

House 12

Residential

136.0 m2

49.2 m2

26.6 m2

45.3 m2

House 13

Middle

130.0 m2

1.8 m2

125.2 m2

43.3 m2

Economic

37.0 m2

7.8 m2

252.0 m2

12.3 m2

House 14

Another important difference is the view of the inhabitants towards security, the most im-

House 15 factor thatMiddle 3 of life for 105.0 m2 groups 13.5 m2 neighbourhood 35.0 m2 portant affects the quality both inm2 relation125.0 to the House 16

Residential

81.7 m2

32.4 m2

273.2 m2

40.9 m2

House 17

Traditional

70.5 m2

28.2 m2

118.3 m2

23.5 m2

together with the car dependence. For the inhabitants living in gated communities, the concept had a 18 positive connotation; while for2 the other90.0 cases rural) House Middle m2 (suburbs, 34.6 CBD, m2 and438.1 m2the connotation 45.0 m2 was negative, related to insecurity. For both groups, life quality is linked with meeting their needs and their well-being, which is directly related to comfort. Finally, the view toward sustainability among both groups is also similar; nevertheless, its economic value is seen as a barrier, which is perceived as unachievable for the low socio-economic segment.

Table 14 Summary of areas in the MMA

ISTMO DE TEHUANTEPEC

The results for the thermal performance measurement in the IT display a relatively small

differentiation between the values from the vernacular and conventional cases as it is displayed in table 15. However, the reports from the inhabitants showed a significant difference concerning their overall comfort satisfaction. Most of the inhabitants from the vernacular cases reported very comfortable conditions, while the inhabitants from the conventional cases reported uncomfortable or very uncomfortable conditions, which was mainly attributed to the hot indoor climate and the low ceilings. Dislike the MMA, the materials from the envelope did not represent objectively an important determinant for comfort, because given the tropical climate, the temperatures in natIn Air T

Air T Δ

House 1ventilated 28.9 °C 4.5 °C urally constructions House 2

31.2 °C

2.4 °C

In wall surf. T

31.0high °C remain

Wall surf. T Δ

11.0 °C throughout

30.0 °C

day

In roof surf. T

In wind speed

In Illuminance

37.0 °C and night.

0.26 Nevertheless,

45 the “natural

38.0 °C

0.22

7.0 °C

materials”, namely wood, and reed,2.0 generated a 38.0 positive connotation towards House 3 32.0 °C adobe, 1.1stone, °C 35.0 °C °C °C 0.25 40 the 33.0 °C effect of the house on the quality of life of the inhabitants, also associated with the sensation of House 4

31.4 °C

3.9 °C

32.0 °C

5.0 °C

0.2

380

House 5

29.4 °C

3.0 °C

33.0 °C

9.0 °C

37.0 °C

0.35

300

House 6 “freshness”.

31.5 °C

0.7 °C

36.0 °C

6.0 °C

38.0 °C

0.12

150

House 7

29.8 °C

2.5 °C

30.0 °C

5.0 °C

34.0 °C

0.6

House 8

29.6 °C

3.2 °C

30.0 °C

11.0 °C

34.0 °C

0.12

House 9

31.2 °C

1.1 °C

38.0 °C

0.08

32.0 °C 7.0 °C Summary of measurements

In Air T

Air T Δ

In wall surf. T

Wall surf. T Δ

In roof surf. T

In wind speed

In Illuminance

House 10

32.2 °C

5.3 °C

34.0 °C

4.0 °C

34.0 °C

0.48

House 11

32.5 °C

4.0 °C

34.0 °C

3.0 °C

35.0 °C

0.28

House 12

34.6 °C

1.7 °C

34.0 °C

4.0 °C

40.0 °C

0.26

House 13

31.2 °C

3.1 °C

32.0 °C

1.0 °C

32.0 °C

0.35

House 14

31.9 °C

0.7 °C

29.0 °C

3.0 °C

29.0 °C

0.56

300

House 15

36.0 °C

-0.2 °C

34.0 °C

5.0 °C

37.0 °C

0.09

House 16

34.5 °C

2.3 °C

33.0 °C

2.0 °C

34.0 °C

0.46

House 17

31.2 °C

4.6 °C

31.0 °C

4.0 °C

32.0 °C

0.48

House 18

34.5 °C

0.3 °C

36.0 °C

3.0 °C

42.0 °C

0.38

130

Vernacular typologies Conventional typologies

Another important factor for comfort in this region was the configuration of the volumes

in the plot. As already stated, correct ventilation is an essential mean to achieve comfort, and it is usually higher in the exterior shadowed spaces. That is why most of the inhabitants reported spending most the time on the terrace or garden. A semi-open configuration, which was found in 4

Table 15 Summary of measurements in the IT

319

of the 6 vernacular cases, is then the best to enhance outside movement. The 3 conventional cases had a closed configuration, in which all the uses of the house are compacted within one volume. This not only subtracts importance from the outside space but also enhances a disconnection with nature. The best performance was found in house 14, which is also shown in table 15. The house that could be called the most primitive has an evident influence from a local knowledge related to the coast. This house complies with most of the passive design strategies that are ideal to maintain an interior comfort balance. In contrast with the MMA, these strategies remain the same throughout the year and can be listed as:

1. Orientation – Usually a north-south orientation is ideal to minimize sun exposure, however this house’s facade creates a lattice effect that could work for any orientation. 2. Thermal mass – The house has a low thermal mass, which can be ideal in this climate to enhance natural ventilation. It also has the best values for indoor surface temperatures, which is due to the good insulation properties of the envelope materials. 3. Openings – The lattice effect of the façade, without the use of glass allows relatively good natural ventilation, which is ideal in humid climates to improve the comfort sensation due to evapo-

4. Results | The Influence of the Vernacular

320

rative cooling of the body. 4. Configuration – The separation of activities into different volumes is primordial as it promotes the use of outside spaces and segregates the concentration of activities and heat gains. 5. Interior space distribution – The completely open floor plan without divisions is a perfect combination with the lattice effect, as it improves crossed ventilation. 6. Height –The high ceilings create a stack effect that maintains the warm air and the radiant heat from the roof far away from the inhabitants.

As explained in the previous section, the behaviour of the inhabitants also had an impact

on their comfort sensation. However, according to the results, discomfort in this region is most likely to be associated with the design of the house rather than the daily decisions of the users. In contrast with the MMA, the opening of doors and windows, which was the first reaction of the inhabitants, has regularly a positive effect on the indoor conditions. Inhabitant 14, showed similar conducts to the rest of the interviewees, who acted mostly in accordance with the expected strategies that can be followed to improve the comfort sensation, which include:

1. Openings – In most of the cases, windows and doors should remain open during day and night when natural ventilation is taken as the main strategy for cooling. In the case of house 14 this was not necessary due to the composition of the facade. 2. Outdoor activity – A common behaviour of the inhabitants in the region is to go outside to perform their activities, like cooking, eating and resting. In addition in the case of house 14 the toilet and working spaces were also external. 3. Indoor activity - Indoor activities are normally minimized, and appropriate furniture like hammocks are used to promote the evaporative cooling of the body. In house 14 there was a notorious preference of the wooden-palm volume and most of the activities were performed there including sleeping. 4. Fan – It is the principal mean to enhance ventilation, as the air speed is normally not sufficient to achieve comfort, however in house 14 it was not necessary as the average wind speed was relatively high. 5. Cooling systems – They are not so common in the region and should be used only when there is a tight envelope and preferably insulated to control the temperature balance.

321

Fig. 194 Axonometric view of house 14

When analysing the other important variable of the hypothesis, there was no significant difference Segmentation

Inhabitants

m2 house

m2 terrace

m2 garden

m2/person

Residential-plus

314.4 m2

315.2 m2

355.7 m2

104.8 m2

between high and low socio-economic segmentation. For example, in contrast with the MMA, House 1

there no notorious variation in the the m2 houses or32.4 them2area per person both House was 2 Traditional 8 size of 70.5 3000.0 m2 between 8.8 m2 House 3

Popular

50.5 m2

9.6 m2

38.0 m2

25.3 m2

House 4

Residential-plus

213.4 m2

115.8 m2

385.6 m2

71.1 m2

House 6status. Residential-plus social

228.7 m2

46.2 m2

47.5 m2

76.2 m2

House 7

Residential

150.0 m2

84.9 m2

8000.0 m2

75.0 m2

House 8

Traditional

90.0 m2

34.4 m2

310.0 m2

22.5 m2

House 9

Residential-plus

69.4 m2

85.9 m2

74.7 m2

groups as it can be seen in table 16. Another fact that can be observed is that there are no examples classified as there2is no evident between ofm2 the house and House 5 as residential-plus, Traditional 90.0relation m2 0.0 m2 the size 53.0 45.0 m2the

4 Summary 298.7 m2 of areas

Segmentation

Inhabitants

m2 house

m2 terrace

m2 garden

m2/person

House 10

Middle

132.0 m2

151.1 m2

42.5 m2

44.0 m2

House 11

Traditional

71.4 m2

42.7 m2

161.2 m2

14.3 m2

House 12

Residential

136.0 m2

49.2 m2

26.6 m2

45.3 m2

House 13

Middle

130.0 m2

1.8 m2

125.2 m2

43.3 m2

House 14

Economic

37.0 m2

7.8 m2

252.0 m2

12.3 m2

House 15

Middle

105.0 m2

13.5 m2

125.0 m2

35.0 m2

House 16

Residential

81.7 m2

32.4 m2

273.2 m2

40.9 m2

House 17

Traditional

70.5 m2

28.2 m2

118.3 m2

23.5 m2

House 18

Middle

90.0 m2

34.6 m2

438.1 m2

45.0 m2

322 4. Results | The Influence of the Vernacular

High socio-economic segmentation Low socio-economic segmentation

The answers and the concept treated by both groups had similarities. The majority of the

inhabitants also related the term quality of life with meeting their needs and their well-being; however, also the family and the neighbours were concepts that constantly appeared in the answers from both groups. In this region, the answers were not necessarily associated with the building technique or materials, but most of them had a notorious reflection of the culture. Security was also an important concept with a positive connotation that had an effect on their quality of life. Finally, the interviewees had also similar views towards the concept of sustainability regardless of their socio-economic position. In most of the cases, it was seen as something necessary to be able to conserve the natural resources for future generations.

Table 16 Summary of areas in the IT

CONCLUSIONS

The main hypothesis of the study, as many other researchers have demonstrated, was that

the vernacular cases would have a better comfort performance than the conventional cases, which would be reflected in the quality of life of the inhabitants. Therefore, this hypothesis was proven and was, in general, valid for both of the case studies. The measured parameters were air temperature, surface temperature, humidity, illuminance, and air velocity. In the region with a semi-arid climate (the MMA), there was a more notorious differentiation than in the region with a tropical climate (the IT) regarding the air and surface temperatures. Nevertheless, in all of the eighteen measured houses, the indoor temperature values remained outside of the usually desirable comfort levels. The same happened in most of the cases with the illuminance and ventilation values. This situation was also expected given the extreme outdoor conditions during summer months, in which the measurements were taken.

However, an important finding is that the comfort sensation of the inhabitants and its

effect on their life quality was significantly higher in the vernacular cases. That can be explained because the use of natural materials in buildings can generate a positive effect on the well-being and cognition of the users. Studies regarding this subject are generally situated in the design of hospitals and health spaces, but might as well apply to the psychological effects in homes (Halpern & Volskunskil, 1997; Rice, Kozak, Meitner, & Cohen, 2006). The results display that most of the inhabitants from the vernacular cases in both of the case studies relate their comfort sensation with the concept of â&#x20AC;&#x153;freshnessâ&#x20AC;?, which at the same time is in many cases associated with a positive effect in their life quality in relation to the built environment. Apart of the building materials, the concept was linked to the configuration of the floor plan, the outside space, and the room height, which are essential aspects to consider while designing in both of the regions. It can also be noted that, even though the temperatures and humidity are generally higher in the IT, the use of air conditioning is more common in the MMA, and it was also reflected within the selected cases.

Further conclusions reveal that in the semi-arid climate the usersâ&#x20AC;&#x2122; behavior has a more

323

significant effect over the indoor conditions and their comfort than in the tropical climate. That can be explained because in both regions the first reaction of the majority of the inhabitants to hot indoor environments is to open the doors and windows, regardless of the housing type. That has a direct effect over the indoor air temperature and the air movement, which normally has a positive effect in tropical climates and a negative effect in arid climates. However, the subject can be further investigated to correlate it with the loss of traditional knowledge for each of the cases.

Another important finding is that even though the conventional cement-based con-struc-

tions have better acceptability during the decision-making process, as it was demonstrated with the preliminary study, further results from the case studies show that the inhabitants of the typologies defined as vernacular valued more the construction once inhabited. These results can also be matched with the ones proposed by Ziccardi (2015). She found that in the north region of Mexico only 57.6% of the inhabitants are satisfied with the building materials of their house, while in the south region 66.4% are satisfied, which could be explained by a higher percentage of constructions with natural materials.

4. Results | The Influence of the Vernacular

324

Another hypothesis of this study was that the quality of life would be dependent on the

socio-economic level, and therefore a considerable difference between the answers from high and low socio-economic groups and between the MMA and the IT was ex-pected. However, this hypothesis was proven mostly to be wrong in this research. Most of the answers between both groups in the two case studies shared significant similarities. Most of the interviewed inhabitants regardless of location and socio-economic position included terms like “needs”, “well-being”, “tranquillity”, and “comfort”, when referring to their quality of life. The most notorious difference within the groups in the MMA was the view towards the concept of security, while in the IT there was no significant difference. The most significant difference between both of the case studies was that in the IT many of the answers included terms related to social relations, a factor that proofed to be more influential within this culture, which was part of the hypothesis.

Moreover, in contrast with the findings from the preliminary study, the results of the field

research showed that there was also no significant difference in the views towards sustainability

between the low and high socio-economic sectors. The preliminary study and previous research (Rohracher & Ornetzeder, 2002) suggested that environmental awareness is directly related to the economic level of the population. However, for the case of the MMA and the IT, it could be argued that the knowledge of the inhabitants regarding sustainability was dependent on age rather than socio-economic position. It can then be concluded from the results of the preliminary study and the field research that there is an increasing conscious concern from the general population in Mexico regarding sustainability. As most of this population is formed by decision-makers in the construction sector, there is a chance to further promote the influence of the vernacular in the future building traditions in the housing constructions in the country.

325

5 CONCLUSIONS WHY SHOULD WE APPLY VERNACULAR BUILDING TRADITIONS IN TODAYâ&#x20AC;&#x2122;S ARCHITECTURE?

From the earliest records of housing constructions in Mexico, building traditions during

the pre-colonial era were manifested by region, with a notorious division between the north, Aridoamerica, and the south, Mesoamerica. They were mainly dependent on the availability of resources and technology, but there is also evidence of their differentiation according to the site and the climate in search of comfort. When the Spaniard colonized the country, they introduced new materials and construction techniques, as well as a completely new culture that modified the way of life of the natives, including their settlements. However, the differentiation between building traditions in relation to the site, the climate, and the regional needs remained. The socio-economic segregation increased, also reflecting in architecture with a division of Spanish and Indian typologies, which the same as the culture, started to merge with time but keeping a vernacular character depending on the region.

After Mexico’s independence, the cultural and socio-economic partition between the

north and the south of the country continued to develop with variations. The north was guided by an influence of the “American” culture, hand-by-hand with industrialization. In contrast, the south experienced slower growth, with a still significant influence of the indigenous culture. However, in both regions, the building traditions in the housing sector after the 1950s were partially substituted by a conventional way of construction that is based in cement as the primary material for the different elements that constitute the house. The cement era, as described in this study, was a consequence of several factors, but mainly due to the strategic positioning of the concrete industry in the country, which had the self-construction housing sector as the principal driver of this construction system. In addition, the uncontrolled growth of settlements generated urban “carpets”, where single-family houses predominated in the landscape.

The standardized building solutions that were and are still regularly used have many ad-

vantages, apparently reducing costs and time of construction. Nevertheless, they usually have a significant proportion of embodied energy and do not react correctly to the climate, causing uncomfortable conditions for the inhabitants, which at the same time affects their quality of life. This study starts from this premise and suggests that the discomfort tends to increase in places with hot climates, where overheating of the buildings is very common in summer. It is therefore centred in the implications that using vernacular building traditions, in oppositions to the described conven-

Fig. 195 House in Oaxaca designed by Arquitectos Artesanos. Taken by author

327

tional techniques might have over the users of housing constructions. Building materials play then a primordial role in the energy and carbon emissions that are produced in housing constructions, and they also have a primary role in the comfort, identity and general appearance of a house.

A preliminary study was first conducted within the national context, in which 100 partic-

ipants were surveyed to understand the decision-making process and the building material preferences better while building a new housing construction. The objective was also to understand which factors could affect their decision the most. The preliminary finding displayed a significant preference in concrete, due to its physical properties like resistance and durability. However, after acknowledging information about price, durability, trend and carbon emissions, the latter had a more significant influence over the update in preference, suggesting an increasing concern from the people over environmental factors. The study served then as a prelude in understanding the users, which in the case of Mexico are usually the decision-makers while building a house.

Nevertheless, the use of building materials and building traditions can significantly vary

depending on local or regional conditions like culture, climate, and availability of resources and

5. Conclusions | The Influence of the Vernacular

328

technology. For this reason, two case studies were selected, one form the north of the country, the Monterrey Metropolitan Area (MMA), mostly with a hot semi-arid climate, and one from the south, the Istmo de Tehuantepec (IT), with a hot tropical climate. The primary purpose was to investigate the influence of the vernacular in contemporary housing constructions and its implications within a specific context. The main research question that was answered with this part of the study was:

How can the influence of the vernacular be identified in contemporary architecture and how does it affect the users in hot climates?

To be able to identify the vernacular influence within a specific context, a methodology

was proposed based on a previous study by Amos Rapoport (1969). A detailed analysis of a determined region is divided into three groups. The first one includes the main socio-cultural context, which relates mainly to the historical and actual population of the place. The second one is the

analysis of the site and the climate, which is related to the historical and actual physical environment of the territory. The third group refers to the construction materials and technology, which again is associated with the historical and actual availability of natural and human resources. In the case of this study, the information was complemented with mappings, graphs and architectural drawings, which helped to synthesize the main aspects of the analysis better.

The analysis for the MMA displayed that for the socio-cultural context the development

of society and partly of their building traditions was dependent on security issues that generated closed social and physical borders. The region has been subject to continuous internal conflicts since the arrival of the Spaniards, which produced a notorious socio-economic segmentation. The settlements started then to develop through spatial segregation, which was further increased with the population expansion that followed a deep industrialization process. This process was guided by an ideal of progress similar to the American Dream, with a notorious external influence from the United States, and from the National immigrants that arrived from other regions. As a result, the urban sprawl grew exponentially, with mainly four different housing systems that were recognized within the Metropolitan Area, which are the Spanish city typology, the suburbs typology, the gated communities and the detached typologies.

The analysis for the MMA also showed that the development of the settlements was linked

for an extended period to the climate and the physical conditions of the site; however, they stopped to be determinant factors together with the drastic urban growth. The bioclimatic evaluation indicated that there are two periods to consider while designing, a colder and drier period between November and March, and a hotter and more humid period between April and October. Given the relatively high temperature variations between day and night, it was considered that the control of solar gains and thermal mass are ideal strategies to follow. The latter was usually achieved with the use of two materials that were commonly available in the region, adobe and sillar. The second one was based on limestone, which is the primary element to produce concrete and glass. These two materials, together with steel, replaced almost entirely the use of natural materials in the region, which became the hub of some of the most important building and material industries in the country. That has not only brought pollution problems, but it also contributed to the fast and uncontrolled growth of the grey horizontal sprawl that predominates in the landscape until today.

329

The analysis for the IT showed that the socio-cultural context has been mainly shaped by

Indigenous, Spanish and external influences and rituals. In the region prevails a direct influence of three pre-Hispanic cultures, the Mixe-Zoque, the Huave, but mainly the Zapotec. Their culture was based on a communal way of life, where the public and semi-public spaces played a primordial role in their activities, which was and is still reflected in the distribution of the settlements until today. With the Spanish occupation, the native identity was transformed into the form of Indian towns, which slowly started to incorporate traits of the European culture. However, the most significant transformation occurred also after industrialization, principally as the result of an uncontrolled population growth that was produced by a refinery that brought labor immigration to the region. The built environment was also transformed with the external influence following a similar process than in the MMA but on a smaller scale. The semi-open housing systems that predominated were gradually replaced by closed structures and detached typologies typical of the generic Mexican landscape.

The previously described semi-open structures and the outside activities were also a re-

flection of the climate in the IT. The high temperatures and humidity throughout the year usually

5. Conclusions | The Influence of the Vernacular

330

generate uncomfortable indoor conditions for the inhabitants. According to the bioclimatic analysis, natural ventilation is the best strategy to follow to achieve comfort. It has been determined that air conditioning and dehumidification systems are regularly also needed; however, they are not common in the region. Through further analysis and conversations with the inhabitants, it was also determined that the earthquakes had had an important influence in the building traditions. Nevertheless, there is no adequate structural knowledge, which has generated an architecture of fear. That together with the cement industry predominance in the country has also provoked that the local materials and technologies (like adobe, tropical wood, burned bricks and tiles) have been replaced with cubic, reinforced, concrete structures. These systems are usually not only inadequate for the climate, but they have also transformed the local identity of the housing constructions, affecting in some way the comfort and quality of life of the inhabitants.

To better understand the effect of the vernacular influence over the inhabitants of con-

temporary housing constructions a field research was carried out in each of the case studies. Eighteen houses were analyzed and measured to get quantitative values that could be related to the

inhabitantsâ&#x20AC;&#x2122; comfort satisfaction. The samples were divided by socio-economic segmentation and defined as vernacular or conventional, based on the building materials and building techniques. The inhabitants were also interviewed in relation to comfort, quality of life, and sustainability to complement the study with a qualitative approach. The primary findings showed an agreement with the main hypothesis, which was that the vernacular cases would have a better performance than the conventional cases. Even though the indoor conditions stayed mostly off the comfort values, the responses from the inhabitants were significantly more positive in the vernacular cases mainly due to a sensation of freshness and a relation to nature, which, in short, answers the second part of the main research question. The implications of the analysis and the findings are explained in the following section.

EXPECTED CONTRIBUTIONS

Some of the advantages of applying vernacular building traditions in contemporary archi-

tecture have been examined throughout the dissertation. Apart from displaying the environmental benefits that have already been widely studied, the purpose of this study was to investigate the socio-cultural causes and effects of their application. The aim was also to provide a mixed mythology approach that can serve as a base for further studies on the topic. As previously mentioned, the research has to be contextualized to a specific region, as solutions regarding sustainability are dependent on the deficits of the site and culture. However, similar problems and solutions can be expected, mainly in those regions with similar backgrounds. Like Mexico, many other countries have gone through a swift transformation with regularly negative local implications. To quote some of the most important researchers in the topic, Vellinga, Oliver, & Bridge (2007, p. 12):

â&#x20AC;&#x153;Given the fact that the vast majority of population growth will take place in those regions where vernacular traditions are still dominant, it would seem that the conservation, regeneration, and development of vernacular traditions is essential to meet the future challenge of the housing worldâ&#x20AC;?.

331

Many of those countries are located in regions with hot climates, where the extreme conditions generate a social, economic and environ-mental impact. Therein lies the urgency to search for existing solutions that any builder can apply to improve the comfort and life quality of the inhabitants.

First of all, the results of the analysis of the development of building traditions in Mex-

ico can serve to anyone interested in the historical background of the country. It can be useful for architects, engineers, anthropologist, archaeologist, etc., as it gathers the findings of many disciplines to give an explanation to the partial loss of vernacular traditions. That chapter is also essential as it can act as a contextual base for any further study that aims to focus on any other region in the country, mainly if it lies on a territory with hot climate. Moreover, it complements the lack of existing graphical information on the subjects throughout mappings and architectural drawings. The further analysis of the case studies might have similar implications but positioned within a specific context. Hopefully, the analysis also serves as a base for architecture students, builders, policy-makers or any other decision-maker in the building sector in the MMA and the IT, as it synthesizes the main aspects to take into account before designing and building a dwelling.

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Another expected contribution of the analysis is to extend the regional knowledge and

practices so that they can be considered in other areas with similar contexts. For example tequio, a common practice from the Ismto region, in which tasks are exchanged among the society, could serve as an example for other cultures of a successful communal way of labour. It represents an alternative solution, which not only activates the local economy, including the building sector but also enhances social relations within the community. Another example that can be observed in the IT is the distribution of spaces in the traditional house, in which the outside dynamics are maximized and the interior space is minimized. The main interior space of the house, the Yoo BidĂł, serves as a gathering and sleeping space, and principally as an altar room. This distribution can also serve as an alternative solution for tropical climates, or as a an example of an atypical combination of uses.

The goal of the field research is to display examples of how the vernacular building tradi-

tions are still applied in contemporary constructions and in todayâ&#x20AC;&#x2122;s way of life. Most of these hous-

es can be added to the examples of good practice that are usually studied when treating the subject of vernacular architecture. However, it also adds a multidisciplinary approach that many of the existing studies lack when analyzing specific typologies or cultures. The results of this approach mainly demonstrate that regardless of the socio-economic position, the vernacular influence has the potential to improve the comfort and quality of life of the inhabitants when comparing them to conventional housing constructions. Therefore, the main expected contribution of the study is to aid in the process of bringing back vernacular building traditions in architecture towards a more balanced relationship with nature.

Another aim is to keep open the topic of regionalism and its effect on the architectural

identity of a place. Even though it was not the main focus of this study, there is an implicit critique to the conventional cement-based building constructions, which apart from their high-embodied energy and their lack of response to the climate, they have generally erased or reduced the regional identity of the settlements in the country. Then, the search for vernacular solutions is also a search for an identity that seems to struggle with the goals of contemporary architecture. Therefore, it is not a romantic view as proposed by Frampton (1987), but more a quest to find a balance between, the past and the future. It is best described by Jimenez Vera (2012, p. 29), when relating to the situation that has gradually transformed the built landscape of the Istmo de Tehuantepec:

â&#x20AC;&#x153;The search for an architectural identity is not at odds with contemporaneity. There must be a well-understood balance between our cultural roots, which are very strong, and our present. So it is not about recreating a set, but it is to pave the way to this society that for years has managed to adapt maintaining its solid culture as a basis of strength, power and welfare. To assume our cultural and patrimonial rescue it is necessary to understand the invaluable legacy that we have. We will have to learn from each traditional detail, without altering its patterns, and then incorporate them into the current designs, creating contemporary architecture that will live up to its legacy.â&#x20AC;?

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FUTURE RESEARCH

The extents and methodology of this dissertation could be further revised. As in any

other research, there are limitations that could be complemented in future studies with similar approaches. However, it is essential that further research on the topic continues with a multidisciplinary approach and with additional focus on quantitative and qualitative analysis as a mixed methodology widens the spectrum when relating socio-cultural and environmental factors. As it was suggested by Marcel Vellinga (2015), when focusing only on technological or physical performance aspects of the constructions, the importance of the embodied culture and the users are usually neglected, which limits or distorts the research. Therefore, there is a need to incorporate a holistic and integrated view on a regional scale to the analysis of any typology or sample in the future.

Nevertheless, there is also a need to relate and analyze specific characteristics of the ty-

pologies or specific behaviours of the inhabitants if the goal is to narrow the study into specialized

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topics. For example, in the case study of the MMA there were only two houses with a courtyard typology, which did not signify a representative sample to obtain conclusions relating the shape of the building with the comfort and effect on the quality of life of the inhabitants. Therefore, future research in that region or arid climates could be specially centred on the relation of already studied essential features of the buildings. In the IT, for example, further research could be focused on the effect of social relations in vernacular architecture, and on how social behaviours affect the comfort and quality of life of the inhabitants. The point is as already determined, that there are many factors that influence sustainability, so a precise focus on each of the factors is also needed to be able to asses the different solutions for the future.

In general, many variables could be related when comparing vernacular and conventional

cases in their inhabitants. For example, the samples in this study were divided by socio-economic segmentation, but the results did not display any significant differences between the two groups. Therefore, further research could also be focused on different independent variables, such as age group, gender, or specific location within a given community. Other socio-cultural values that

were not included in the surveys could also be added, such as religion and political affiliation, to search for other types of relations between the social environment and the inhabitantsâ&#x20AC;&#x2122; behaviour. Furthermore, other programmes could also be investigated, for example, office, commercial, or industrial buildings where a significant amount of energy is consumed worldwide, and where the comfort and quality of life of the users are also essential for sustainable development.

Other recommendation is that ideally, the comfort measurements should be carried out

or simulated throughout the whole year to be able to more precisely analyze the response of the building materials, forms and techniques to the climate conditions. Other equipment could also be added to measure more physical values in the houses, such as the temperature of different surfaces, energy consumption, air quality or noise, which could implicate more detailed explanations of the comfort parameters. The interviews and surveys with the inhabitants could also be carried out in different conditions, for example during winter, as responses may vary depending on the comfort levels that are experienced at the moment of the field study.

Another possibility for future research is to further focus on the economic ad-vantages or

disadvantages of using vernacular building traditions. It is usually implied, as it is also reflected in the results of this research, that sustainability is expensive and sometimes difficult to achieve within low socio-economic segments of the population. However, research focused in other developing countries (Gavieta, 1991; Shafii, Arman Ali, & Othman, 2006) suggests that using passive strategies, and vernacular materials and techniques can contribute to achieving affordable housing and costs savings in comparison to other types of constructions. Therefore, further studies in Mexico can also include the Life-Cycle Cost Analysis (LCCA) of the buildings.

Moreover, it is also essential to further analyze the consequences of self-building con-

cerning the future development of vernacular traditions and sustainability. The analysis and the results of the preliminary study display the significant percentage of the population in Mexico of self-builders. This situation is prevalent in developing countries, so it also accounts for a considerable proportion worldwide. It is a niche that has to be further studied, as it represents the majority of the constructions and therefore it has a significant impact in a countryâ&#x20AC;&#x2122;s environment, image and its society. So, in the case where architects and planners are not considered during the pro-

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cess, there is a need to further research on other possible influences, that can affect the cognition of the builders and that promote the use of building techniques suited to locally resourced materials.

Finally, future research regarding vernacular building traditions should keep evolving

together with the application of new technologies. By applying traditional knowledge in combination with new findings in the building sector, it should be every day easier to meet comfort requirements and to improve the life quality of users in buildings, while at the same time keeping a balance with the needs of our natural environment. So, to answer the question posed in the title of this chapter, we should apply vernacular building tradition in todayâ&#x20AC;&#x2122;s architecture because it implies that the socio-cultural and the physical context in which we are designing was taken into account. It also suggests that lessons have been learned from successful examples, but also from mistakes of the past, and therefore there is a possibility that we can better answer the challenges of the future.

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7 LIST OF FIGURES

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Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 31

House in Tehuantepec. Rural landscape in Nuevo Leon Kรถppen-Geiger classification world map Paquime Arid and tropical climates in Mexico Main cultures that developed in Aridoamerica and Mesoamerica Construction section of a typical cliff dwelling Construction section of a typical dwelling from Paquime Construction section of a typical Olmec dwelling Construction section of a typical Zapotec dwelling Construction section of a typical oval Mayan dwelling Construction section of a typical Mayan Tandem dwelling Construction section of a typical Aztec dwelling Map of Mexico with Spanish cities and haciendas Construction section of a typical Spanish elite dwelling Construction section of a typical hacienda dwelling from arid climates Construction section of a typical hacienda dwelling from tropical climates Map of Mexico with the indian towns around 1800 AC Urban and rural population growth in Mexico Inhabited housing constructions growth in Mexico Map of Mexico with metropolitan areas with more than 100,000 inhabitants Steps to self-build a dwelling Predominant materials in walls in Mexico (1930-2010) Predominant materials in roofs in Mexico (1970-2010) Section of the proposal by Pascal Arquitectos for the state of Quintana Roo Section of the proposal by Casa Publica for the state of Sinaloa Typical durability of materials Average price of materials per m2 in Mexico Predominant material in walls in Mexico Embodied carbon emissions Estimated marginal means of update for each condition given by fact type

Cover 12 14 28 32 34 37 39 43 45 47 49 51 54 57 59 61 62 66 66 70 74 76 76 87 87 92 92 93 93 96

Figure 32 19th century house in Garcia, Nuevo Leon Figure 33 Municipalities that form the Monterrey Metropolitan Area (MMA) Figure 34 Schematic representation of the Spanish City typology urban distribution Figure 35 Schematic representation of the suburbs typology urban distribution Figure 36 Schematic representation of the gated community typology urban distribution Figure 37 Schematic representation of the detached typology urban distribution Figure 38 Level of marginalization in the MMA Figure 39 Climate in the MMA Figure 40 Average temperature per hour in Monterrey Figure 41 Maximum and minimum average year temperature in Monterrey Figure 42 Average wind speed in Monterrey Figure 43 Sun path in Monterrey Figure 44 Comfort according to humidity in Monterrey Figure 45 Average rainfall in Monterrey Figure 46 Situation map of the MMA with topography, urban sprawl and rivers Figure 47 Psychrometric chart and design strategies of outdoor measured yearly values in Monterrey Figure 48 Typical floorplan of a courtyard house in the MMA Figure 49 Vegetation in the MMA Figure 50 Geomorphology in the MMA Figure 51 Material extraction and industry over geomorphology map in the MMA Figure 52 Satellite image of the MMA Figure 53 Satellite image of Garcia Figure 54 Axonometric view of house 1 Figure 55 Ground floor plan of house 1 Figure 56 Transversal section of house 1 Figure 57 Exterior facade of house 1 Figure 58 Courtyard loggia of house 1 Figure 59 Axonometric view of house 2 Figure 60 Ground floor plan of house 2 Figure 61 Transversal section of house 2 Figure 62 Exterior facade of house 2 Figure 63 Courtyard loggia of house 2 Figure 64 Axonometric view of house 3 Figure 65 Ground floor plan of house 3 Figure 66 Transversal section of house 3 Figure 67 Exterior facade of house 3 Figure 68 Kitchen/entrance of house 3 Figure 69 Satellite image of Monterrey Figure 70 Axonometric view of house 4 Figure 71 Ground floor plan of house 4 Figure 72 Transversal section of house 4 Figure 73 Courtyard facade of house 4 Figure 74 Dinning room/kitchen of house 4 Figure 75 Axonometric view of house 5 Figure 76 Upper floor plan of house 5 Figure 77 Ground floor plan of house 5 Figure 78 Transversal section of house 5 Figure 79 Exterior facade of house 5 Figure 80 Living room of house 5 Figure 81 Axonometric view of house 6 Figure 82 Upper floor plan of house 6 Figure 83 Ground floor plan of house 6 Figure 84 Transversal section of house 6 Figure 85 Exterior facade of house 6 Figure 86 Dinning room of house 6

100 108 112 113 114 115 118 120 122 122 122 124 124 124 126 128 133 134 136 142 144 146 148 149 149 150 150 152 153 153 154 154 156 157 157 158 158 160 162 163 163 164 164 166 167 167 167 168 168 170 171 171 171 172 172

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Figure 87 Satellite image of Santiago Figure 88 Axonometric view of house 7 Figure 89 Ground floor plan of house 7 Figure 90 Transversal section of house 7 Figure 91 Exterior facade of house 7 Figure 92 Living room of house 7 Figure 93 Axonometric view of house 8 Figure 94 Ground floor plan of house 8 Figure 95 Transversal section of house 8 Figure 96 Exterior facade of house 8 Figure 97 Interior corridor of house 8 Figure 98 Axonometric view of house 9 Figure 99 Upper floor plan of house 9 Figure 100 Ground floor plan of house 9 Figure 101 Transversal section of house 9 Figure 102 Exterior facade of house 9 Figure 103 Dinning room of house 9 Figure 104 Municipalities of the Istmo region Figure 105 Typical adaptation of the Zapotec dwelling into the urban grid imposed by the Spaniards Figure 106 Population growth Figure 107 Situation map of the IT with topography, urban sprawl and rivers Figure 108 Degree of marginalization in the IT Figure 109 Schematic representation of a semi-open typology urban distribution Figure 110 Schematic representation of closed typologies in an urban context Figure 111 Schematic representation of detached typologies in an urban context Figure 112 Average temperature per hour in Tehuantepec Figure 113 Maximum and minimum average year temperature in Tehuantepec 350 Figure 114 Average wind speed in Tehuantepec Figure 115 Sun path in Tehuantepec Figure 116 Comfort according to humidity in Tehuantepec Figure 117 Average rainfall in Tehuantepec Figure 118 Climate in the IT Figure 119 Psychrometric chart and design strategies with measured yearly outdoor values from Tehuantepec Figure 120–127 Situation of some buildings in the IT after the earthquake of September 2017 Figure 128 Vegetation in the IT Figure 129 Material extraction and industry over geomorphology map in the IT Figure 130 Satellite image of the Istmo region in Oaxaca Figure 131 Satellite image of Tehuantepec Figure 132 Axonometric view of house 10 Figure 133 Ground floor plan of house 10 Figure 134 Transversal section of house 10 Figure 135 Exterior facade of house 10 Figure 136 Interior of Yoo Bidó of house 10 Figure 137 Axonometric view of house 11 Figure 138 Ground floor plan of house 11 Figure 139 Transversal section of house 11 Figure 140 Exterior facade of house 11 Figure 141 Interior of Yoo Bidó of house 11 Figure 142 Axonometric view of house 12 Figure 143 Upper floor plan of house 12 Figure 144 Ground floor plan of house 12 Figure 145 Transversal section of house 12 Figure 146 Exterior facade of house 12 Figure 147 Interior room of house 12

174 176 177 177 178 178 180 181 181 182 182 184 185 185 185 186 186 190 193 196 198 200 202 203 204 206 206 206 208 208 208 210 212 216 220 222 224 226 228 229 229 230 230 232 233 233 234 234 236 237 237 237 238 238

Figure 148 Figure 149 Figure 150 Figure 151 Figure 152 Figure 153 Figure 154 Figure 155 Figure 156 Figure 157 Figure 158 Figure 159 Figure 160 Figure 161 Figure 162 Figure 163 Figure 164 Figure 165 Figure 166 Figure 167 Figure 168 Figure 169 Figure 170 Figure 171 Figure 172 Figure 173 Figure 174 Figure 175 Figure 176 Figure 177 Figure 178 Figure 179 Figure 180 Figure 181 Figure 182 Figure 183 Figure 184 Figure 185 Figure 186 Figure 187 Figure 188 Figure 189 Figure 190 Figure 191 Figure 192 Figure 193 Figure 194 Figure 195

Satellite image of Juchitan Axonometric view of house 13 Upper floor plan of house 13 Ground floor plan of house 13 Transversal section of house 13 Exterior facade of house 13 Dining room of house 13 Axonometric view of house 14 Ground floor plan of house 14 Transversal section of house 14 Exterior facade of house 14 Interior space of house 14 Axonometric view of house 15 Upper floor plan of house 15 Ground floor plan of house 15 Transversal section of house 15 Courtyard facade of house 15 Living room of house 15 Satellite image of Asuncion Ixtaltepec Axonometric view of house 16 Ground floor plan of house 16 Transversal section of house 16 Exterior facade of house 16 Kitchen/dinning room of house 16 Axonometric view of house 17 Ground floor plan of house 17 Transversal section of house 17 Exterior facade of house 17 Courtyard loggia of house 17 Axonometric view of house 18 Ground floor plan of house 18 Transversal section of house 18 Exterior facade of house 18 Living room of house 18 User Matrix of the axonometric views of the studied typologies Summary of results of the specific characteristics of the houses in the MMA Summary of results of the specific characteristics of the houses in the IT Summary of the relation of comfort results between the MMA and the IT Summary of the relation of comfort results between the vernacular and conventional typologies in the MMA Summary of the relation of comfort results between the vernacular and conventional typologies in the IT Summary of the relation of quality of life results according to socioeconomic segmentation in the MMA Summary of the relation of quality of life results according to socioeconomic segmentation in the IT Summary of the relation of quality of life results between vernacular and conventional typologies in the MMA and the IT Summary of the relation of sustainability results according to socioeconomic segmentation in the MMA and the IT Axonometric view of house 1 Axonometric view of house 14 House in Oaxaca designed by Arquitectos Artesanos

240 242 243 243 243 244 244 246 247 247 248 248 250 251 251 251 252 252 254 256 257 257 258 258 260 261 261 262 262 264 265 265 266 266 268 270 272 274 280 286 290 296 300 306 312 316 321 326

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Table 1 Distribution of the working population by income Table 2 Market segmentation in Mexico Table 3 Market segmentation summary Table 4 Thermal conductivity and mass of common building materials Table 5 MMA - Outdoor measured average values Table 6 MMA - Indoor measured average values Table 7 IT - Outdoor measured average values Table 8 IT - Indoor measured average values Table 9 MMA - Indoor measured average values according to building type Table 10 MMA - Difference between indoor and outdoor average values according to building type Table 11 IT - Indoor measured average values according to building type Table 12 IT - Difference between indoor and outdoor average values according to building type Table 13 Summary of measurements in the MMA Table 14 Summary of areas in the MMA Table 15 Summary of measurements in the IT Table 16 Summary of areas in the IT

82 84 104 139 278 278 278 278 284 284 288 288 315 318 319 322

9 APPENDIX

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APPENDIX I

PRELIMINARY STUDY: BUILDING MATERIAL PREFERENCE ONLINE QUESTIONNAIRE

Informed Consent PURPOSE: The purpose of this study is to determine the social preference of building materials in new constructions in the United States and the factors that influence decisions while choosing the materials. The results of this study will contribute to scientific knowledge, but will probably have no benefits or risks to you as a participant. The entire study should take about 5 minutes to complete. CONFIDENTIALITY: Any information that you provide will be kept strictly private, confidential, and anonymous. Your name will not be attached to your survey responses in any way. Results from this study will be presented as statistical summaries, but no information will be presented about individual participants. If you decide to take part, you are still free to withdraw at any time and without giving a reason. Nevertheless, you have to complete the survey in order to get your Clickworker fee. Many of the questions are optional, so in many cases, you can also skip to the next part of the survey. I give my consent to participate in this study. I have read and understood the above information. Do you agree to participate in this questionnaire? ___ Yes ___ No

1. What is your sex? ___ Male ___ Female 2. What is your year of birth? ________________________________________________________________

3. What is your place of birth? ________________________________________________________________

4. Please indicate your occupation ___ Management, professional, and related ___ Service ___ Sales and office ___ Farming, fishing, and forestry ___ Construction, extraction, and maintenance ___ Production, transportation, and material moving ___ Government ___ Student ___ Retired ___ Unemployed ___ Other________________________________________________________

5. Please indicate the answer that includes your entire household yearly income before taxes. Information about income is very important to understand. Would you please give your best guess? ___ Less than $2,000 ___ $2,000 to $3,999 ___ $4,000 to $5,999 ___ $6,000 to $9,999 ___ $10,000 to $19,999 ___ $20,000 to $49,999 ___ More than $50,000

6. Counting everyone you included, how many people live usually in your home? ________________________________________________________________

7. What best describes your type of home? ___ Single-family house ___ Apartment in a multi-storey building ___ Multiplex house (row house, duplex, triplex, etc.) ___ Unit in a vecindad ___ Other________________________________________________________

8. If you would build your own house/building, how would decisions be taken? Choose one or more options. ___ by your own ___ by your family ___ by an architect or designer ___ by contractor(s) ___ Other________________________________________________________

9. If you could choose the building materials of your house/building, what would you choose mainly for the exterior? Please rank them in order of preference. Drag and drop into the desired position.

(randomized order)

______ Adobe ______ Stone ______ Wood ______ Bamboo/reed ______ Concrete ______ Glass ______ Fired brick ______ Other

10. Which are the factors that affect the most your material choice? Please rank them in order of importance. Drag and drop into the desired position.

(randomized order)

______ Physical properties (structural/durability) ______ Costs ______ Cultural context (trend/tradition) ______ Appearance ______ Environmental factors (energy/carbon emissions) ______ Other

11. Facts

(Only one fact per participant with randomized order)

Stone, concrete and fired brick are the materials from the list with the higher typical life expectancy.

Concrete, burned brick, and stone are the most used materials in construction in Mexico.

Bamboo, straw, adobe, and burned brick are usually the cheapest materials to build with in Mexico.

The use of concrete, fired bricks and glass affect usually climate change the most.

12. After the given information, If you could choose the building materials of your house/building, what would you choose mainly for the exterior? Please rank them in order of preference. Drag and drop into the desired position.

(randomized order)

______ Adobe ______ Stone ______ Wood ______ Bamboo/reed ______ Concrete ______ Glass ______ Fired brick ______ Other

APPENDIX II

COMFORT AND QUALITY OF LIFE SURVEY

Informed Consent PURPOSE: The purpose of this study is to determine the perception of comfort and quality of life of the inhabitants in contemporary construction in the Monterrey Metropolitan Area / Istmo de Tehuantepec. Indoor and indoor environment measurements will be performed to determine the air temperature, relative humidity, illuminance level, and air velocity. A survey will be carried out with one of the inhabitants. The results of the study will contribute to the scientific knowledge however they will probably represent a benefit or risk to you as participant. The study takes 3 hours to be completed. CONFIDENTIALITY: Results from this study will be presented as statistical summaries, but no information will be presented about individual participants without previous consent. I give my consent to participate in this study. I have read and understood the above information. Do you agree to participate in this study? ___ Yes ___ No

1. What is your sex? ___ Male ___ Female

2. What is your year of birth? ________________________________________________________________

3. What is your place of birth? ________________________________________________________________

4. In what year was the house built? ________________________________________________________________

5. Please indicate your occupation ______________________________________________________________

6. Counting everyone you included, how many people live usually in your home? ______________________________________________________________

7. In which space(s) do you spend most of your time while being in your house? ______________________________________________________________

8. How would you describe your activity in that space? ___ Sitting/lying down ___ Stading with low actuvity ___ Stading with mid actuvity ___ Stading with high actuvity

9. What is your general comfort satisfaction in the house? ___ very comfortable (+3) ___ comfortable (+2) ___ slightly comfortable (+1) ___ neutral (0) ___ slightly uncomfortable (-1) ___ uncomfortable (-2) ___ very uncomfortable (-3)

10. When it is not comfortable, what is the main reason? Choose one or more options. ___ Hot / very hot ___ Cold / very cold ___ The materials are hot ___ The materials are cold ___ The humidity is low ___ The humidity is high ___ There is too much light ___ There is not enough light ___ There is too much wind ___ There is not enough wind ___ It is very loud ___ It is not cosy ___ Other ________________________________________________________________

11. What do you usually adjust when it is not comfortable? Choose one or more options. ___ Open / close windows ___ Open / close shutters ___ Turn on the fan ___ Turn on the air conditioner ___ Turn on the heater ___ Turn on the lights ___ Change clothes ___ Other ________________________________________________________________

12. What means quality of life to you? ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________

13. Which aspects of your neighbourhood have an effect on your quality of life? ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________

14. Do you think that the way in which your house is designed and built has an effect on your quality of life? In what sense? ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________

15. What means sustainable architecture to you? ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________

Measurements: Outdoor air temperature_______________________________ Indoor air temperature _______________________________ Outdoor relative humidity _______________________________ Indoor relative humidity _______________________________ Outdoor illuminance _______________________________ Indoor illuminance _______________________________ Outdoor wind speed _______________________________ Indoor wind speed _______________________________ Outdoor wall surface temperature _______________________________ Indoor wall surface temperature _______________________________ Outdoor roof surface temperature _______________________________ Indoor roof surface temperature _______________________________

Building Materials: Exterior walls_______________________________________________________________________________________________ Interior walls_______________________________________________________________________________________________ Roof________________________________________________________________________________________________________ Outside floor_______________________________________________________________________________________________ Inside floor_________________________________________________________________________________________________ Windows____________________________________________________________________________________________________

Observations: ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________

Architectural drawings:

DECLARATION OF AUTHORSHIP

The Influence of the Vernacular: Building traditions in contemporary housing architecture of hot climates in Mexico

I hereby declare that the present doctoral thesis is entirely my own work and without the use of any unauthorized assistance. Any content which has been taken verbatim or paraphrased from other sources has been identified as such. This thesis has not been submitted in any form whatsoever to an examining body.

Rodrigo Alba Krasovsky