ROBUST ARCHITECTURE. LOW-TECH DESIGN

EDELTRAUD HASELSTEINER

Editor Edeltraud Haselsteiner

Authors Thomas Auer, Gaetano Bertino, Edeltraud Haselsteiner, Anna Heringer, Johannes Kisser, Andrea Klinge, Steffi Lenzen, Bernhard Lipp, Ute Muñoz-Czerny, Eike RoswagKlinge, Ursula Schneider, Helmut Schöberl, Bertram von Negelein, Robert Wimmer, Maria Wirth, Thomas Zelger

Project editing Steffi Lenzen, Anne SchäferHörr (project management), Cosima Frohnmaier (project examples), Jana Rackwitz (copy editing German edition and layout), Charlotte Petereit and Selma Popp (editorial team), Sandra Leitte (proofreading German edition)

Translation into English Susanne Hauger, New York (US)

Copy editing (English edition) Stefan Widdess, Berlin (DE)

Proofreading (English edition) Meriel Clemett, Bromborough (GB)

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Robust Architecture

The energy transition today can only succeed with some measure of technology. The dependencies that Ivan Illich presented are therefore unavoidable. Central to his thoughts on Energy and Equity [1], however, is the reduction of the per-capita energy allotment to a level that does not exceed the amount critical to societal wellbeing. Low-tech design and robust architecture, as elucidated by this publication, take up this question. The hope that technology represents the sole solution for the climate crisis, on the other hand, relegates the responsibility to future generations.

What are responsibility and equity in construction? And does the issue not go beyond this, requiring a limitation to more modest means, a reversion to local building traditions and the potentials of simplicity?

Take a centuries-old farmhouse in the Alps, built according to the artisanal tradition of solid timber from the surrounding forest. It is situated so that the location allows for an orientation optimised against weather influences and capable of withstanding other adverse conditions (e.g. the danger of winter avalanches) as much as possible. The ground plan concept varies with size, but as a rule boils down to what is necessary to accommodate a residence and livestock under one roof, so that in winter the living spaces adjacent to the livestock pens can benefit from the animals’ body heat. The kitchen and its hearth are positioned so that

appropriate ventilation flaps can be used to heat other living spaces next to or above it. Long-lasting wood protection is provided by appropriate constructive means, such as large roof overhangs. This is obviously simple, yet functional, aesthetic, intrinsically valuable and extremely efficient in multiple respects.

But the farmhouse is not the only building that works like this. Observations of old stone houses in Wales and Tuscany as well as clay buildings in East Asia and Africa yield similar insights. Built with craftsmanlike precision, using whatever was locally available, these houses are geared toward actual requirements and optimised for relevant weather conditions. For this reason, a lot of these houses are still around, and have stood the test of time remarkably well in many respects.

Nowadays, placing even a single opening into a building envelope in accordance with standards has become a science. Aside from a knowledge of diverse rules and regulations, it generally requires specialised technical literature offering pages-long guidance. Last but not least, the users need voluminous handbooks to operate the buildings in compliance with the rules. This seems absurd, but is in many regards a feature of contemporary practice – all around the world, in fact. Thanks to globalisation, industrialisation and rationalisation of building production, traditional building culture and its associated knowledge and crafts-

“A low-energy policy allows for a wide choice of lifestyles and cultures. [...] If, on the other hand, a society opts for high energy consumption, its social relations must be dictated by technocracy, and will be equally distasteful whether labelled capitalist or socialist.” [1]

Ivan Illich

The basic reflections and the idea for this publication were created during a study sponsored by the research programme “Stadt der Zukunft” (City of the Future) by the Austrian Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK). The editor thanks the sponsor for its support and the publisher for the chance to realise this project as well as for the excellent collaboration during its creation.

manship have gradually been lost. The separation of ground plan and facade and the detachment from locally anchored and traditional building methods have led to a building method that is supposedly egalitarian. The use of “smart technology” in the building sector has removed the effort to produce heat and fresh air from human activity. At the same time, demand for comfort and expectations of year-round uniform comfort levels have risen, while the willingness to work with natural seasonal or weather-related temperature fluctuations and cycles has fallen. Conversely, increasing sensory overload and the accelerating pace of living have led to a growing desire for sensory experiences and resonance [2]. We want experiences such as a fire in a log burner that slowly warms a room. As glass high-rises in desert regions, specialised high-tech facades in salt-laden sea air and oversized villas in the sprawling developments outside metropolitan centres arise, gobbling fossil fuels for air conditioning, paving over large tracts of land and leading to exploding maintenance costs, the question to ask is whether this building approach is really sensible in the long term. How is it possible that all the energy-saving measures implemented over the last few decades have led to the consumption of ever more energy? And in these days of climate and energy crises, is it not high time to return to locally adapted and needoriented building methods in order to arrive, if possible, at a new, robust architecture? An architecture that meets today’s requirements and demands for comfort, but that once again guarantees long-lived, intrinsically valuable buildings – or better yet: restores the value of existing buildings – by taking into account simple low-tech parameters. Resilient buildings of natural materials

that do not end up in hazardous waste landfills at the end of their service life, but whose components are rather reused or allocated to biological material loops. That would be wonderful!

Low-tech design is intended to pull the value of natural building materials and buildings, a high regard for craftsmanship and a conscious appreciation of nature and our ecosystem more solidly into focus. With this in mind, we have gone in search of reliable criteria, scrutinised design processes and found exemplary projects that show that this method of building is not only possible, but actually even relatively simple. Low-tech construction can be much more than – as is commonly assumed – just foregoing automatic ventilation. However, the examples also illustrate that, in view of existing norms, standards and funding guidelines, low-tech buildings are possible only after a careful assessment by the clients of the costs and risks involved. The only way to exit from the spiral of energy dependence is via a sweeping paradigm shift. We need robust architecture that lasts a long time, consumes few resources and is needoriented and resilient. We need it so that the building sector will soon no longer be responsible for immense energy consumption and waste removal costs. We need it so that, from an architectural perspective, we can look forward to a positive future.

Edeltraud Haselsteiner & Steffi Lenzen

July 2022 Notes

Illich 1978 [2] Rosa 2016

About 4,000 used timber window frames from all EU countries form the approx. 3,000 m2 area of the glass facades on the administrative headquarters of the Council of the European Union in Brussels (BE) 2015, Philippe Samyn & Partners with Studio Valle and BuroHappold

1

Direct solar-gain zeroenergy houses, Trin (CH) 1994, Andrea Rüedi. The solar buildings in Trin are considered pioneering structures in solar architecture. They cover all heating requirements through incident solar radiation and passive

thermal storage. Largescale glazing of the south facade, a directly sun-exposed floor of polished and darkcoloured concrete as well as indirectly heated solid walls and ceilings of limestone make houses without conventional heating possible.

things is seen as responsible for the rise in allergies [4].

Increasingly, planners and architects are tending toward a stronger reduction of “technology”, instead favouring low-tech design over highly complex, automationand technology-dependent building concepts.

Eco tech, low tech, high tech

In the 1970s, as a reaction to the oil crisis of that era, the first reform movements toward an environmentally oriented low-tech architecture were created. Their goal was to present an ecologically sound alternative to the expansive and increasingly industrially oriented building industry. The countertrend was expressed primarily in the form of do-it-yourself initiatives in residential construction, based on environmental building methods using natural materials. This first “energy crisis” also brought the issue of forward-looking concepts for energy supply into the consciousness of broad swaths of the population. The first attempts to experiment with thermal collectors in self-build groups eventually resulted in a broad and extremely successful DIY initiative for solar collectors. While the potential of passive solar-energy utilisation was recognised quite early in architectural circles, the first step toward solar technology was taken with the implementation of solar collectors. Since then, the development of “eco or green technology” has progressed by leaps

and bounds. In pursuit of maximum energy efficiency, passive-house building concepts were developed in which heat loss is significantly reduced thanks to a completely airtight building envelope. The building functions using automated ventilation but no conventional heating. The energy response of a building due to climatic conditions, its structural form or its usage can now be determined very precisely through building simulations. Meanwhile, owing to advances in energy efficiency technologies, even positive-balance plus-energy buildings are now possible.

Energy-saving construction

In the early 1990s, climate engineering and new computer simulation options were linked with a revolutionary change in building design: “With the aid of computer simulations, we are in a position to adapt buildings to natural energy flows. New concepts of passive modulation can be developed. The implementation of novel technologies during the design can make technology in the finished building largely unnecessary. Intelligent design makes the building itself into a climate device: Rooms become ventilation channels, windows and doors become valves, ceilings turn into light reflectors and facades into heaters.” [5]

Developments of recent years, however, have pointed in a different direction. Today, technology largely makes up for caprice in design. A comfortable interior

READ = Renewable Energies in Architecture and Design. The text was developed by Thomas Herzog in 1994/95 within the framework of a READ Project of the European Commission DG XII, and the wording was discussed and agreed upon in collaboration with leading European architects.

2 a—b Autonomous energy residence, Maladers (CH) 2011, Matthias Stöckli Architektur. Building upon the first experimental solar houses by Andrea Rüedi in Trin, numerous successor structures were created that furthered the development of autonomous energy construction and solar architecture. The building concept relies on direct solar gain with thermal storage in floors, walls and ceilings and natural thermal lift. A photovoltaic array on the south side delivers electricity; cooking is done with wood only in winter, otherwise with solar electricity.

climate, lighting and heated spaces can be produced anywhere, regardless of the surrounding conditions and outdoor climate. The prevailing question is not one of feasibility, but rather of cost and the affordability of comfort.

But the initial approaches to energy-efficient building in the early 1990s were based strongly on building concepts optimised for the passive use of solar energy or environmental cycles without the implementation of technology. The preamble of the “European Charter for Solar Energy in Architecture and Urban Planning”, adopted by the READ (Renewable Energies in Architecture and Design) Group in 1996, reads: “Roughly half of the energy consumed in Europe is used to run buildings. A further 25 % is accounted for by traffic. Large quantities of non-renewable fossil fuel are used to generate this energy, fuel that will not be available to future generations. The processes involved in the conversion of fuel into energy also have a lasting negative effect on the environment through the emissions they cause. In addition to this, unscrupulous, intensive cultivation, a destructive exploitation of raw materials, and a worldwide reduction in the areas of land devoted to agriculture are leading to a progressive diminution of natural habitats. This situation calls for a rapid and fundamental reorientation in our thinking, particularly on the part of planners and institutions involved in the process of construction. The form of our future built environment must be based on

a responsible approach to nature and the use of the inexhaustible energy potential of the sun. The role of architecture as a responsible profession is of far-reaching significance in this respect. Architects must exert a far more decisive influence on the conception and layout of urban structures and buildings, on the use of materials and construction components, and thus on the use of energy, than they have in the past. The aim of our work in the future must, therefore, be to design buildings and urban spaces in such a way that natural resources will be conserved and renewable forms of energy – especially solar energy – will be used as extensively as possible, thus avoiding many of these undesirable developments.” [6]

Energy-saving building concepts of the 1990s were characterised by their ambition to make optimal use of the sun as an energy source and to establish a “solar architecture”. In this context, the direct solar-gain houses in Trin and subsequent buildings are considered pioneers of solar architecture (Figs. 1 and 2). By now, the implementation of components for the utilisation of solar energy is an inherent partt of every design. However, the focus has noticeably shifted from an architecture and design oriented toward solar gains to the solar technology itself. That is to say that building concepts are usually reduced to “making room” for technical components for the use of solar energy, solar collectors and PV panels.

The Sustainable Low-tech Building

Edeltraud Haselsteiner

The goal of sustainable construction is to implement a mutually balanced combination of ecological, economic and social sustainability and insure its continuation over the entire life cycle of the building. To this end, sustainable low-tech building concepts question the use particularly of information and communications technology (ICT) and building automation systems as a long-term best approach to sustainable construction.

System limits and the role of technology in the life cycle

Though ICT systems offer options for building optimisation, their “intelligence” lies in carefully thought-out design. In his book Low-Tech Light-Tech High-Tech. Bauen in der Informationsgesellschaft (Building in the Information Society), Klaus Daniels provides the first comprehensive look at the entry of information technology into the building sector in the German-speaking sphere, an important milestone in the development of so-called “smart” building technology:

“Intelligently designed and operated buildings, often falsely referred to as “smart buildings”, are characterised not only by their highly interconnected information, communications and building automation systems, but primarily by the fact that they are capable of serving user needs directly from the environment, bypassing the utilisation of technical installations.” [1] In order to be able to not only maintain,

but properly use buildings throughout their entire lifetime requires a well thoughtout and forward-looking design concept. Energy efficiency during operations should be valued just as highly as the consumption of embodied energy or the recyclability of materials. The same is true for sustainable low-tech buildings. The overarching question is, of course, what temporal or spatial dimensions define the limits of “low tech”. In concrete terms, it must be clarified whether the technology input should only be included when it can be directly connected to the construction, operation or deconstruction of the building, or whether the technological component of the manufacture of the building materials and parts should also be considered. One can also differentiate between assessments in the temporal dimension, along life cycle phases, or in the spatial, according to distance from the building.

The life cycle is roughly subdivided into four phases: Design and manufacture (raw materials) – assembly, construction and renovation – use, operation and maintenance – deconstruction and disposal. Different life cycle phases require different forms of technological input (Fig. 2). In the operations phase, a look at the technological contributions can be further simplified by considering the spatial distance to the building [2]:

• Technology directly in or on the building or plot (heating, ventilation system, collectors, etc.)

materials from the original industrial building and materials from buildings destroyed in the war. An additional goal of the renovation was to create a renewed awareness of recycling and reuse.

• Amount of neighbourhood technology required for the building (energy distributor, water and sewer connections, etc.)

• Amount of municipal /urban technology required for the building (energy supply, waste disposal and recycling, etc.)

• Amount of supra-regional technology required for the building (extraction of energy source material, etc.)

Technological contributions during the design and in material/commodity production

According to the estimates of international experts, the share of global emissions due to information and communications technologies (ICT) now lies in the 2.1– 3.9 % range [3]. The upper limit of this estimate for the carbon footprint of computers, servers and the Internet thereby exceeds the 3 % contribution (as of 2018) to global greenhouse gas emissions of planetwide air traffic. In addition, the energy consumption of ICT grows by 9 % annually [4]. In the absence of targeted regulatory measures, ICT emissions will rise. Nevertheless, the direct and indirect environmental impact of the increasing use of digital media is being constantly underestimated.

2 Life cycle phases and technology used (examples)

Design and Manufacture

With regard to the comparability and ecological balance assessment, and also as a starting point for design decisions, however, this spatial categorisation provides little relevant information. For the following investigation of low-tech concepts, therefore, a material-related approach has been chosen. Significant technological contributions are those that can be proportionately attributed to a building and are either generated in the building itself or in its immediate surroundings in connection with its construction, use or deconstruction throughout its entire life cycle.

For the past few decades, digital technologies have played an important role throughout building planning. All design processes are now carried out with the help of CAD programs, various design software tools and electronic aids. In the past years, the use of building simulations to estimate the thermal-energetic behaviour of a building and the utilisation of Building Information Modelling (BIM) has also increasingly become the norm.

A considerable technological contribution is therefore already generated in the conceptual and design phases. The extraction of raw materials, material manufacture and transport account for further sizeable inputs due to technology. The criteria of

Assembly, construction, renovationUse, operation and maintenance

Design: ITMachines for excavation and site preparation

Technology used in extraction of raw materials

Technology used in construction, assembly and installations

Deconstruction and disposal

Technology used to produce building materials and components

Transport of commodities and materials

Technology used to renovate the building structure

Transport of people, building materials and components

Technology linked to building use

Equipment and components used in building operations, control and regulation (heating, cooling, ventilation, lighting, etc.)

Equipment and components used for upkeep and maintenance

Transport of people and goods for operations, upkeep and maintenance

Deconstruction planning / organisation

Technology used in deconstruction and disposal

Technology employed in reutilisation, recycling, reuse, etc.

Transport of waste, materials and components

1 a—b Klan Kosova Television Studio, Pristina (RKS) 2017, ANARCH, Astrit Nixha. A former industrial building in Pristina was renovated for the private television station TV Klan using primarily natural local materials, recycled demolition

The term “low tech” in architecture is currently not precisely defined. Rather, it signals a reassessment of the assumption that technology represents a cure-all for society, and expresses an experimentation with other options through greater utilisation of nature-based solutions, the use of natural materials and a preference for analogue processes. However, this is less a complete rejection of technology per se or of its evaluation in and of itself, and more about a holistic consideration of complete systems with regard to the goals of regenerative sustainability.

Regenerative sustainability aspires to the creation of auto-regenerating social and ecological systems. In this sense, natureand biology-based solutions, local environmental resources as well as social and cultural potential represent the weightbearing pillars of an integrated low-tech overall concept. The three aspects of sustainability – ecology, economy and social concerns – form the framework. However, since regional building traditions require more personal responsibility and activity on the one hand, and represent multiple fundamental building blocks of low-tech building concepts on the other, an expansion of the framework to include what scientific-political discourse dubs the fourth pillar (the “cultural” or “political-procedural” component of “institutions”, that is to say, “participation”) is essential [9]. Figure 4 gives an overview of examples of low-tech options that could make contributions toward the achievement of sustainability goals.

Low-tech architecture aims to maximise the use of local resources, natural elements and active principles in order to avoid the excessive consumption of energy and resources. The critical stance towards implemented technology is intended to scrutinise its effective contributions to the overall system and, with a view to the entire life cycle, demand more efficiency, social acceptance and health and well-being. Therefore, based on the four sustainability aspects, sustainable low-tech design can be characterised by the following basic design strategies:

• Ecology = a climate and resourceonserving building method that broadly employs available environmental conditions (climate, location and origin) for its operations and makes significant contributions to the regeneration of the ecosystem

• Economy = a sufficient, robust and costeffective building method that targets a reduced technological footprint throughout the whole life cycle (production –operation – deconstruction)

• Social concerns = a needs-based and socially equitable building method that provides for an agreeable level of comfort, provisioning and waste removal while simultaneously eliminating potential for harm and competition with others for food for this and future generations

• Participation / culture = a simple, understandable, locally proven building method based on personal responsibility, which promotes self-build construction, DIY maintenance and upkeep and the regional building culture

Aspects

and possible impact levels of low tech (examples)

A Ecological quality ECOSYSTEM — climate, regeneration, resilience RESOURCES — form, energy, recycling systems

B Economic quality

ROBUSTNESS — life cycle costs, homogeneity, quality SIMPLICITY — functionality, maintenance, servicing

C Social quality

SUFFICIENCY — minimisation of requirements, area consumption, intensity of use HEALTH — natural commodities, material, relationship between humans and nature

D Participation / process quality

RECYCLABILITY — flexibility of use, deconstruction, documentation RESPONSIBILITY — adaptation to climate change, (building) culture, equity

Low-tech matrix

In the following sections, these individual facets will be examined in greater detail and explained by way of a comprehensive low-tech matrix (Fig. 5 and Fig. 8, p. 30f.).

Location, climate and ecosystem

Low-tech design strategies take a sitespecific approach. In this approach, local environmental resources are chosen as the means or catalysts of an energy-efficient and ecological initial design. For example, depending on the site, wind, sun, soil or water could represent the resources driving a holistic approach to a supply and waste removal solution, or locally available building materials could form the foundation for the basic design of the building. In contrast to technology-driven concepts, which tend towards a broad compartmentalisation against environmental influences that are unstable or hard to calculate in order to ensure that comfort standards remain constant, low-tech concepts rely on sufficiency and resilience. The goal is to make use of the dynamic ecological unity formed by people, building, location, nature and ecosystem and to develop optimised concepts based on it.

Robustness and resource conservation

High-quality building standards and construction details based on structures of proven craftsmanship are guarantors of robustness and a long (service) life. Beyond this, carefully thought-out and scrupulously executed structural details can reduce the use of technologically costly building equip-

ment. Among the central goals are a sufficient and resource-conserving use of primary materials and the avoidance of emissions in all life cycle phases. This includes avoiding transport routes as well as doing without large-scale earth-moving and excavation. Additional characteristics of a low-tech design concept are material homogeneity, measures taken to reduce complexity in building details and the conscious decision to allow for “ageing” such as the greying of facades, as long as there are no associated impairments to the structure.

Energy and supply

Low-tech design relies on harnessing simple active principles and employing natural renewable environmental resources to supply buildings efficiently and based on a sufficient use of technology. An (energy-) efficient building method and an energetically optimised form create the starting point for as low a demand as possible for additional energy in the operations phase. Site-specific factors such as microclimate and topography join regionally available energy and environmental potentials (sun, earth, groundwater, wind, internal heat sources, seasonal and daily rhythms, etc.) as well as the efficient use of natural material and primary resource characteristics to form the supporting pillars of an energy concept based on low tech. In addition, it is important to harmonise eventual supply and removal cycles in the building with those of the surrounding buildings and the location (exhaust heat – heating / cooling, combined

5 Low-tech matrix (abbreviated version)

Design Strategies

Edeltraud Haselsteiner

Climate and location-optimised building form

“You cannot implement things after the fact that were not factored in at the beginning. So if the climate is not already part of the early design phase, its influences on factors like form and typology are not taken into account and must be compensated for later with technological measures in or on the building.” [1] If technology is to be used in a meaningful way, therefore, climate is the critical design factor. The morphological configuration of the building is an especially dominant variable.

Bioclimatic building on Tenerife

In the south of Tenerife, one of the Canary Islands, a total of 25 bioclimatic houses were built that test the various options to address the climatic conditions of the location (Fig. 1). All the buildings are rented out on a temporary basis as holiday homes. The bioclimatic house is protected from the strong Tenerife winds by high, circular walls of volcanic stone. At the same time,

air chambers and air circulation allow these double-skin stone walls to regulate the indoor climate. The building has neither heating nor air-conditioning. Green flat roofs, rainwater recovery, electricity from the neighbouring wind farm and building materials from the excavated ground combine with additional design solutions to yield this sustainable overall concept.

Cultural and Tourism Centre in Terrasson

The creation of the Culture and Tourism Centre in Terrasson in the Dordogne marks the first time in architectural history that gabion walls have been used for their energy-absorbing mass. The unworked stone placed within the wire mesh comes from a nearby rock quarry. The building concept itself is based on the principle of a greenhouse. In winter, direct insolation heats the natural stone wall and a portion of the ground slab; in summer, water from the natural stone wall and from surrounding trees supplies evaporative cooling (Fig. 2). Openings between the walls and the glass

1 a–c

Bioclimatic building, ITER Park holiday house, Granadilla, Tenerife (ES) 2000, Ruiz Larrea & Asociados

Low tech: Building form and surface optimised to the microclimate of the location, use of regional materials and excavated ground substance, natural regulation of the indoor climate

2 Cultural and tourism centre, Terrasson (FR) 1994, Ian Ritchie

Architects

Low tech: Large thermal storage mass, optimised solar gains, natural ventilation, cooling via water evaporation

3 a–b

Grüne Erde-Welt commercial building, Pettenbach (AT) 2018, architekturbüro arkade with terrain: integral designs

Low tech: Recycling of the previous building, natural lighting and ventilation via green atria, optimised and site-adapted structure

Grüne Erde-Welt follows the central theme of the business, which is to live and operate in connection with nature and people (Fig. 3). The sales and workshop building stands on the site of a former building so as not to burden additional green spaces. All the concrete from the demolition was recycled and reused in the new building. The structure is optimised in many details in order to keep the ecological footprint as small as possible. Natural materials such as timber and sheep’s wool determine the building concept. The structure is nestled within a 5-ha garden complex of native plants and trees. Indoors, thirteen organically connected green atria generate an agreeable interior climate and provide natural lighting and ventilation.

4 Single-family house STONE TERRACE, Hiroshima (JP) 2008, Kazuhide Doi Architects

Low tech: Climateand site-adapted architecture, use of available materials (stone masonry) and traditional building technology, natural ventilation, cooling and heating

forest

streetwater 4

basin 3

water garden cool breeze from the water 2 b

removal a Design Strategies

terrace

House on a terraced slope in Hiroshima

The concept of Stone Terrace, a singlefamily house, takes up the functional principles of rice terraces and confers the advantages of light, water and wind for agricultural production onto architecture. The location has a humid, subtropical climate with hot summers and frequent precipitation even during the “dry” months. In summer, the building is cooled via natural thermal lift: On the north side, air that has been cooled above a pool of water is drawn in, while warm air can escape along the ceiling on the south. The sloped roof shades the interior in the summer and maximises sunlight in winter (Fig. 4).

Energy Potential of the Environment

Edeltraud Haselsteiner

Sun houses

Hungarian architect Pierre Robert Sabady is considered one of the pioneers of solar architecture in Europe. In the 1970s, he published an article enumerating the “seven pillars of the bio-solar house” [1]. In the article, he uses his single-family bio-solar house Hälg in Lucerne, which he designed in 1977, to explain how buildings can be energetically optimised. With a trapezoidal ground plan, he references Socrates’ original concept (see p. 56). While the broader south side is generously glazed, the narrower north side, which accommodates secondary rooms, is practically windowless. The ground plan is organised so that the stairwell, cellar and attic form interior buffer zones, while a generous conservatory in front of the south facade represents an outer buffer zone or greenhouse (Fig. 1). This basic principle of solar architecture has remained unchanged through the present and is among the most efficient types of energy-conserving construction. Houses heated by the sun do better in terms of life cycle costs than comparative conventional buildings, and their global warming potential is lower than that of normal low-energy and passive houses [2].

Communal living project near Vienna

After the oil crisis of the 1970s and a massive rise in oil prices, energy-saving buildings and alternatives to oil as a heating fuel became a dominant theme, especially in the construction of single-family homes. In

1984, Georg W. Reinberg realised a communal living project that married the principles of solar architecture and demands for healthful building materials to a community resolved on codetermination. The form of these buildings, placed in a stacked arrangement along a narrow, long, southfacing slope, was based on the need to achieve large sun-exposed surfaces while minimising mutual shading (Fig. 2). The individual buildings themselves are subdivided into three thermal zones: Conservatories and large glazed surfaces to the south, a middle zone including the sanitary core designed for the highest temperatures, and storage rooms on the north side.

Direct solar gain house

In the early 1990s, the development of direct solar-gain houses (Fig. 1, p. 10) that had been begun by Andrea Rüedi with his experimental solar buildings in Trin made it possible to establish appropriately constructed and designed houses optimally oriented toward the sun and without the need

1 Section and floor plan, bio-solar house Hälg near Lucerne (CH) 1977, Pierre Robert Sabady

1 North-oriented buffer zone

2 South-oriented buffer zone/ conservatory

3 Warm air solar heating roof

4 Central hearths

5 Living room

6 Dining area

7 Kitchen

Low tech: Solar architecture, sustainable materials

for conventional heating. The five-storey single structure in Zweisimmen follows in the tradition of this basic idea (Fig. 3). Its western facade is slightly twisted towards the south in order to gain longer sun exposure during the winter. The solid timber construction is combined with a timberconcrete composite ceiling and a rammed earth floor to provide the necessary mass for energy storage, while the stairwell serves as a buffer zone for the interior rooms on the north side. Adhesives and chemical additives were avoided entirely to ensure a healthy indoor environment. The solid tim-

ber walls are joined with dowels, meaning that the building can be disassembled and its materials can be reutilised after deconstruction. Interior heat sources, in conjunction with the sun, suffice to keep the house at a comfortable temperature year-round. The building has neither central heating nor ventilation.

Residential building in Paris

The fact that solar architecture with passive components, based on an energetically optimised orientation and ground plan concept, can function in a densely built-up

3 a–b

Office and residence building, direct solar-gain house in Zweisimmen (CH)

2014, N11 Architekten

Low tech: Solid timber construction with no central heating

4 a–b

Residential building, Paris (FR) 2013, Babled Nouvet Reynaud Architectes

Low tech: Passive solar architecture, natural ventilation

2 a–b Communal living project, Purkersdorf near Vienna (AT) 1984, Reinberg ZT GmbH

a urban environment even as social housing is demonstrated in a building by Babled Nouvet Reynaud Architectes in Paris (Fig. 4, p. 59). The double facade incorporating usable conservatories with living spaces arranged behind them faces south to benefit from solar irradiance. The conservatories function as climatic buffers; a fibre-reinforced concrete slab acting as a storage wall absorbs the radiative heat intensified by the outer pane and releases it later into the living spaces [3].

Active energy facades

Even though solar thermal energy and photovoltaics have by now made technically mature and affordable solutions for harvesting solar energy available, there have been repeated initiatives to utilise the vertical facade surfaces for energy generation as well. An active energy facade system developed by Rudolf Schwarzmayr controls the solar influx through moveable louvres on the facade (Fig. 5). These employ the solid walls directly to store energy and are therefore also well-suited for renovations, since they can be mounted onto pre-existing solid walls. During times of energy demand and solar irradiation, the louvres open automatically to allow the heat to penetrate into the wall. Depending on the temperature and weather, the function of the facade components can be expanded beyond energy generation to simultaneously include shading and cooling. A corresponding building prototype is currently being tested and evaluated [4]. As in other active energy systems such as solar thermal energy and photovoltaics, the issue of whether this can be classified as low tech is a question

of definition. If the focus is predominantly on the longevity and robustness of the overall system, then the implementation of technological means must be viewed in those terms and in those of energy usage.

Passive solar energy facades

Phase change or viscoelastic materials, also called latent heat storage materials due to their properties, are able to store thermal energy during phase transitions, for example when changing from a solid to a liquid state, without themselves heating up. This has huge advantages for lightweight construction: Heat can be stored in significantly less mass and volume, since the storage capacity of these materials increases by multiples in the vicinity of their melting point. Architect Dietrich Schwarz developed a passive solar facade component with an integrated heat storage module based on salt hydrate crystals. The crystals absorb heat during the day and re-emit it into the interior as radiant heat when the room temperature drops. Anteriorly placed prismatic glass reflects the light of the high summer sun, but allows the rays through when the incident angle is small,

5 a–b Garden studio research building, Thermocollect active energy facade, Rudolf Schwarzmayr

6 Senior citizens’ residences, Domat / Ems (CH) 2004/2015, Dietrich Schwarz

7 Natural ventilation schematic a wind-driven ventilation

b thermal-lift-driven ventilation

c ventilation via wind and thermal lift combined

8 Qaa reception hall in a house with a wind tower (malqaf) and a windcatcher (badgir)

9 Natural ventilation, water evaporation and thermal storage masses that cool termite mounds in hot climates

as in winter. This passive solar architectural concept was employed, among other places, in a senior citizens’ residence in Domat-Ems (Fig. 6) and in the new Marché International office building near Winterthur [5].

Natural ventilation

The positive effects produced by the natural ventilation of indoor spaces, or airing out rooms by opening windows, are not merely environment and energy-related.

From the perspective of the residents, these actions are seen as a chance to make direct contact with nature or to satisfy their need for fresh air. The natural movement of the air comes from pressure differentials that result from temperature differences. As a consequence, natural ventilation can occur either through wind or through thermal lift (Fig. 7).

Using wind forces or natural air currents to ventilate and cool the interior spaces of buildings has a similarly ancient tradition as does solar architecture. In the Persian Gulf and in the regions of the Mediterranean, wind towers are among the hallmarks of classical architecture. Their ability to cool rooms makes them the precursors of air conditioners. Their function relies entirely on thermal lift, specifically on the fact that warm air rises, while the denser cold air sinks toward the ground. Ventilation openings, which can vary in design depending on the location and the wind conditions, “catch” the “cool breeze” skimming along the ground or coming from the sea and channel it through the building. During windless periods, the stack or chimney effect supplies the necessary air exchange:

Heat, which has been stored throughout the day in the solid walls, is emitted into the space and drawn upward. At the same time, fresh and cool air flows in through doors and windows to replace it. This principle of natural cooling is often supported by combining it with water evaporation. In such cases, air from the wind tower is channelled through a damp cellar or over water-filled basins. The water evaporates in the cool but dry air and cools it even further (Fig. 8). In the design of natural ventilation systems, an exact climatic and usage-specific analysis is therefore needed so that the prevailing local air current conditions are understood. It is now possible to use computer simulations to analyse airflow and its effects in response to various influencing factors. Natural ventilation requires a driving force which guides air currents through a building by pressure or suction. Pressure differentials produced at the building envelope by thermal lift and wind can provide this. The strength of the suction effect depends on the temperature difference and the effective height. For this reason, tall buildings are especially wellsuited to a ventilation concept that relies on thermal lift.

Over the course of evolution, nature has developed numerous methods for protection against heat and cold that can be useful in architecture, as well. The Trinervitermes termite colonies in Africa, for example, build mounds more than 30 m high and tunnel down to the groundwater (Fig. 9). By means of a clever ventilation system, the structure is naturally conditioned through water evaporation and the resulting evaporative cooling [6].

isierung_id3512.pdf?m=1646386494& (last accessed 03.05.2022)

[7] Hülsmeier, Petzinka In: Detail 6/2001

Hülsmeier, Frank; Petzinka, Karl-Heinz: Sanierung der Gebäudehülle. In: Detail 6/2001, p. 1084–1094

[8] Bathen 2022

Bathen, Anette: “Kreative und gemeinschaftliche Kirchenumnutzungen | Urbane Produktion.ruhr“. On 11 January 2022

https://urbaneproduktion.ruhr/kreativeund-gemeinschaftliche-kirchenumnutzungen/ (last accessed 25.03.2022)

[9] Detail 5/2014

Fisch, Rainer: Kirchenumnutzung — sakral profan suboptimal. In: Detail 5/2014, p. 398–404

Renovation Strategies

[1] Wilke 2013

Wilke, Sibylle: Bauabfälle. Umweltbundesamt. Dessau-Roßlau 2013. www.umweltbundesamt.de/daten/ressourcen-abfall/verwertung-entsorgungausgewaehlter-abfallarten/bauabfaelle (last accessed 17.02.2021)

[2] Auer, Franke 2020

Auer, Thomas; Franke, Laura: Robuste Architektur. In: Bundesinstitut für Bau-, Stadt- und Raumforschung (eds.), Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019, Publication series Zukunft Bauen: Forschung für die Praxis. Bundesinstitut für Bau-, Stadt- und Raumforschung (Federal Institute for Research on Building, Urban Affairs and Spatial Development). Bonn 2020, p. 40–52

Klinge 2020

Klinge, Andrea: Weniger Technik — mehr Gesundheit. In: Bundesinstitut für Bau-, Stadt- und Raumforschung (eds.): Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019, Publication series Zukunft Bauen: Forschung für die Praxis. Bundesinstitut für Bau-, Stadt- und Raumforschung (Federal Institute for Research on Building, Urban Affairs and Spatial Development). Bonn 2020, p. 82 – 97

C ASSESSMENTS

Low Tech in the Context of International Building Evaluation Systems and Standards

[1] Global Status Report 2017

UN Environment and International Energy Agency: Towards a zero-emission, efficient, and resilient buildings and construction sector. Global Status Report 2017; www.worldgbc.org/newsmedia/global-status-report-2017 (last accessed 02.02.2021)

[2] Brown et al. 2018

Brown, Martin et al.: Sustainability, Restorative to Regenerative. An exploration in progressing a paradigm shift in built environment thinking, from sustainability to restorative sustainability and on to regenerative sustainability. Published by COST Action CA16114 RESTORE, Vienna 2018. www.eurestore. eu/wp-content/uploads/2018/ 05/

RESTORE_booklet_print_END.pdf (last accessed 01.05.2021)

Cole 2012

Cole, Raymond J.: Regenerative design and development: current theory and practice. In: Building Research & Information, Vol. 40, No. 1, 2012, p. 1–6 doi:10.1080/09613218.2012.617516

Reed 2007

Reed, Bill: Shifting from ‘sustainability’ to regeneration. In: Building Research & Information Vol. 35, Nr. 6, 2007, p. 674–680 doi: 10.1080/09613210701475753

[3] Endres 2020

Endres, Elisabeth: Hightech versus Lowtech oder einfach nur robust?. In: Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019. Bundesinstitut für Bau-, Stadt- und Raumforschung (Federal Institute for Research on Building, Urban Affairs and Spatial Development). Published by the Federal Institute for Research on Building, Urban Affairs and Spatial Development. As of January 2020. Bonn 2020, p. 74 – 81

[4] Daniels 2000

Daniels, Klaus: Low-Tech — Light-Tech — High-Tech. Building in the Information Age. 1st corrected edition. Basel et al. 2000, p. 218

[5] Haselsteiner et al. 2021

Haselsteiner, Edeltraud et al.: Drivers and Barriers Leading to a Successful Paradigm Shift toward Regenerative Neighborhoods. In: Sustainability, Vol. 13, No. 9, 2021, Art. No. 9, doi: 10.3390/su13095179

[6] Reed et al. 2009

Reed, Richard et al.: An International Comparison of International Sustainable Building Tools. European Real Estate Society (ERES), eres2009_331, Jan. 2009.

https://ideas.repec.org/p/arz/wpaper/ eres2009_331.html (last accessed 02.03.2021)

SBi, GXN 2018 Statens Byggeforskningsinstitut (SBi); GXN (eds.): Guide to sustainable building certifications. Copenhagen 2018

[7] Forsberg, de Souza 2021 Forsberg, Mara; de Souza, Clarice Bleil: Implementing Regenerative Standards in Politically Green Nordic Social Welfare States: Can Sweden Adopt the Living Building Challenge? In: Sustainability. Vol. 13, No. 2, 2021, Art. No. 2, doi: 10.3390/su13020738

[8] SBi, GXN 2018 (see note [6]) Berardi 2012 Berardi, Umberto: Sustainability Assessment in the Construction Sector: Rating Systems and Rated Buildings. In: Sustainable Development, Vol. 20, No. 6, 2012, p. 411–424 doi: https://doi.org/10.1002/sd.532

E STRATEGIES

[1] Sölkner et al. 2014 Sölkner, Petra Johanna et al. 2014.: Innovative Gebäudekonzepte im ökologischen und ökonomischen Vergleich

über den Lebenszyklus. Publication series Berichte aus Energie- und Umweltforschung 51/2014, Vienna 2014 (last accessed 29.11.2021) https://nachhaltigwirtschaften.at/resources/hdz_pdf/ berichte/endbericht_1451_innovative_ gebaeudekonzepte.

pdf?m=1469660917& [2] Rüdi, Watter, Schürch 2016

Rüdi, Andrea; Watter, Jörg; Schürch, Peter: Solararchitektur: Häuser mit solarem Direktgewinn. Zurich 2016

[3] Endres 2020

Endres, Elisabeth: Hightech versus Lowtech oder einfach nur robust? In: Lowtech im Gebäudebereich: Technical symposium TU Berlin 17.05.2019, 1st edition, as of January 2020, Bundesinstitut für Bau-, Stadt- und Raumforschung, eds. Bonn: Bundesinstitut für Bau-, Stadt- und Raumforschung, 2020, p. 74–81 [4] Endres 2019

Endres, Elisabeth: Parameters to Design Low-Tech Strategies. Presentation at the Powerskin Conference. Delft Jan. 2019 http://pure.tudelft.nl/ws/files/69585347 /679_3_679_3_10_20190325.

pdf#page=289 (last accessed 30.09.2021)

[5] Endres 2017

Endres, Elisabeth: Parameterstudie LowTech Bürogebäude. Technical University of Munich. Chair of Building Technology and Climate Responsive Design. Munich 2017, p. 60 https://docplayer.org/165733295Parameterstudie-low-tech-buerogebaeude.html (last accessed 30.09.2021)

[6] see Note [3], p. 80

[7] Krause, Leistner, Mehra 2020 Krause, Pia; Leistner, Philip; Mehra, Schew-Ram: Einsatz und Auswirkung von Vegetation bei autochthonen Bauten. In: Bauphysik 4/2020, p. 184–195 doi: 10.1002/bapi.202000015

[8] Oswalt 1994

Oswalt, Philipp: Wohltemperierte Architektur. Neue Techniken des energiesparenden Bauens. Heidelberg 1994, p. 55 [9] ibid. [10] ibid.

[11] Erber, Roßkopf-Nachbaur 2021 Erber, Sabine; Roßkopf-Nachbaur, Thomas: Low-Tech Gebäude. Prozess Planung Umsetzung. Commissioned by the Climate and Energy Committee / Environmental Commission of the International Lake Constance Conference IBK, Constance 2021 [12] ibid.

[13] Brown et al. 2018

Brown, Martin et al.: Sustainability, Restorative to Regenerative. An exploration in progressing a paradigm shift in built environment thinking, from sustainability to restorative sustainability and on to regenerative sustainability. COST Action CA16114 RESTORE. Vienna 2018

Authors

Edeltraud Haselsteiner

Edeltraud Haselsteiner studied architecture at TU Wien and earned her doctorate in the theory of architecture. She is a project leader, researcher, exhibition curator and an architecture journalist for sustainable architecture, urban planning and mobility. She is the founder of the research institute URBANITY, which equally addresses issues of gender, participation, the history and theory of architecture and art.

Thomas Auer

Thomas Auer is Professor of Building Technology and Climate Responsive Design at TU Munich and an executive at Transsolar. He works with renowned architecture firms all over the world on prize-winning projects that are characterised by innovative design and integral energy concepts. In his research he focuses on resource consumption, residential quality and robustness. He is a member of the Akademie der Künste (Academy of Arts) and of the Bundesstiftung Baukultur (Federal Building Culture Foundation) convention.

Gaetano Bertino

Gaetano Bertino studied structural engineering and architecture with a specialisation in forensic engineering. He is currently a project manager at alchemia-nova and is completing his doctoral degree at the University of Natural Resources and Life Sciences in Vienna on the topic of circular solutions for sustainable architecture.

Anna Heringer

For Anna Heringer, architecture is a tool for improving living conditions. Her buildings in Bangladesh, Ghana, Austria, Germany and other locations represent a global strategy for sustainability that is based on the utilisation of local resources. Among other places, she has taught and is teaching at Harvard University, ETH Zurich and the University of Art and Design in Linz and is the recipient of numerous prizes including the New European Bauhaus Award, the Obel Award and the Aga Khan Award for Architecture.

Johannes Kisser

Johannes Kisser studied technical chemistry. In 1998 he began working in the waste industry, and was soon dedicating himself to circular economy solutions. He has initiated many projects, and is also an evaluator, consultant and lecturer. After many years as the CEO, he was made Technical Director of the alchemia-nova group in 2019. His strong systems approach combines innovation with inspirations from nature and with social transformation.

Andrea Klinge

Andrea Klinge is a Professor of Circular Construction at the University of Applied

Sciences and Arts in Basel. Her teaching and research are focused on recycling-oriented low-tech construction based on natural building materials. Andrea Klinge worked in various architecture firms in London, Rome and Berlin for over ten years, after which she established the research division at ZRS Architekten in 2013.

Steffi Lenzen

Steffi Lenzen studied architecture at the RWTH Aachen University and in Paris. She worked as an architect for several years before she completed practical training at DETAIL, where she has since worked as an editor. In 2019, she became team leader of the editorial department. Her special interests include timber construction and topics connected with sustainability.

Bernhard Lipp

Bernhard Lipp studied technical physics at TU Wien. He is the managing director of the Austrian Institute for Building Biology and Ecology (IBO) and founding member of the ÖGNB, as well as a member of the klimaaktiv executive committee. He researches comfort and stress and develops quality assurance concepts for buildings and environmental criteria for residential funding.

Ute Muñoz-Czerny

Ute Muñoz-Czerny is an architect and an anthropologist. She conducts research in the areas of indoor air quality, user comfort and energy efficiency. In 2013, she completed her education as a specialist in clay at the Handwerkskammer Koblenz. Ute MuñozCzerny is qualified to issue building certifications (klimaaktiv, ÖGNB).

Eike Roswag-Klinge

Eike Roswag-Klinge is a professor at TU Berlin and has been the director of the Natural Building Lab there since 2017. He is a founding member of ZRS Architekten Ingenieure in Berlin (2003). For more than 20 years he has been working with communities of different cultural and climatic backgrounds to create futureproof, climate and resource-oriented architecture based on natural raw materials.

Ursula Schneider

Since 2000, Ursula Schneider has been the director of POS architekten. For over 30 years, her focus has been environmental and climatesensitive architecture. Starting in 2001, she has increased her work in the areas of innovative and applied building research and consulting on the topics of passive houses, daylight architecture, the plus-energy standard, CO2-neutral construction, Cradle to Cradle, recyclability, user comfort and the greening of buildings. In the context of her active engagement as a teacher and lecturer she communicates her values for a future-oriented architecture.

Helmut Schöberl

Helmut Schöberl has been working in building physics for over 25 years. Schöberl & Pöll GmbH is one of the major building physics firms in Austria, and has been doing pioneering work in numerous passive house projects for more than 20 years. Helmut Schöberl is active on technical standards committees at Austrian Standards and has received many prizes, among them three Staatspreise (national awards), which are among the highest distinctions conferred by the Republic of Austria.

Bertram von Negelein

Bertram von Negelein has a diploma in biology and is employed in the public relations department of Transsolar.

Robert Wimmer

Robert Wimmer studied mechanical engineering and process engineering at TU Graz and TU Wien and earned his doctorate with a thesis entitled “Flex-Fuzzy Logic Expert System, ein integrativer Ansatz zur Bewertung von technischen Systemlösungen aus dem Gesichtspunkt nachhaltiger Entwicklung” (Flex-Fuzzy Logic Expert System, an integrative approach to the evaluation of technical system solutions from the perspective of sustainable development). He is the director of the scientific research association GrAT – Gruppe Angepasste Technologie (Adapted Technology Group). Robert Wimmer coordinates (inter)national development and demonstration projects with an emphasis on system solutions for sustainable development through adapted technologies. He also does consulting work for businesses and agencies and teaches at various universities.

Maria Wirth

Maria Wirth studied Environmental Technology & International Affairs at TU Wien. She is currently a project manager and researcher at alchemia-nova, specialising in the use of nature-based solutions for improvements in urban water management as well as circular food systems.

Thomas Zelger

Thomas Zelger has held an endowed professorship for energy-efficient and user-friendly buildings and neighbourhoods at the University of Applied Sciences Technikum Wien since 2016. Before that, he did research and practical work for over 20 years at the Austrian Institute for Building Biology and Ecology (IBO) in the fields of passive house construction, plus energy construction, building ecology, comfort research and building physics. Thomas Zelger publishes on the topics of comfort, building ecology, plusenergy neighbourhoods and environmental passive house building part catalogues.