Eco Façades as a Feature in the City Sustainability Ana Lídia Virtudes C-Made - Centre of Materials and Building Technologies, Department of Civil Engineering and Architecture, University of Beira Interior, Covilhã, Portugal
Maria Manso C-Made - Centre of Materials and Building Technologies, Department of Civil Engineering and Architecture, University of Beira Interior, Covilhã, Portugal
ABSTRACT: Cities are dominated by building structures to the detriment of natural elements such as water, vegetation or soil, causing problems of congestion, pollution and lack of green spaces. In the domain of urban rehabilitation eco façades are surprising and unexpected concepts. Given the most recent and compulsory Portuguese urban rehabilitation principles and their emphasis upon the improvement of green spaces in historic areas, eco façades can be an opportunity to bring life, beauty and health to the city. This paper aims to reflect on the benefits of eco façades as a feature in the city sustainability, especially in the urban rehabilitation, identifying the advantages of their utilization as an enhancement of the quality of city image, especially in dense urban areas.
1 INTRODUCTION Vegetation has been used in buildings and as part of the construction of cities for many centuries. Historical examples, like the vegetation in the Hanging Gardens of Babylon, the grape vines climbing the buildings walls in the Greek and Roman Empires (Newton et al., 2007), and the climbing plants covering European and American building façades of the 19th century, have revealed the use of plants as ornamental elements of buildings envelope. In the beginning of the 20th century, the Garden Cities of Ebenezer Howard demonstrated that was possible to use green elements as part of town planning. Since the Industrial Revolution, urban population has increased significantly. Nowadays, more than half of the world´s population lives in urban areas, which occupy around three per cent of the earth´s land area. Urban density was followed by new organizational models based on the expansion and dispersion of cities. Urban expansion is causing severe functional and ecological problems, like: increasing levels of pollution (water, air, noise, soils or aesthetic) and energy consumption, lack of amenities, traffic congestion, unhealthy housing, under-utilization of infrastructures, high maintenance costs and absence of green spaces. All these problems have called into question the meaning of the city and its interaction with nature. Consequently, one of the main goals now, in terms of urban sustainability, is to concentrate activities instead of promoting urban expansion. This containment or even a shrinking process of cities will consequently lead to the resizing of urban perimeters (Rogers & Gumuchdjian, 1997). In this context, it is becoming important to redefine public spaces, making them more dynamic, inhabitable and sustainable (AA.VV., 2008a).
2 CITY SUSTAINABILITY VERSUS URBAN REHABILITATION 2.1The sustainability in the urban context Since the 1990s, the concept of urban sustainability has been discussed. Nowadays, city pol policies must follow a sustainable development, making an effort to achieve social justice, sustai sustainable economies and environmental sustainability (AA.VV., 1994), as decided in the Aalborg European Conference on Sustainable Cities & Towns in 1994. Building structure dominates the urban environment to the detriment of natural natural elements. However vegetation should be an important tool to achieve urban sustainability. Vegetation has several benefits (social, economic, environmental, cultural and aesthetic) with the urban context (Fig. 1). One of the social and economic benefits of the application of vegetation is the improvement of property value (Ichihara et al., 2011), since the building scale until the neighbourhood in which it is integrated. Consequently, rehabilitated buildings contribute to making a dynamic perspective in the he city environment. The integration of plants in the urban context, contributes positively to the local environment. Vegetation is a climate moderator, helping to reduce the imperviousness of soil and contributing to storm water management, improving the air quality through the production of oxygen, aabsorption of pollution like CO2 and heavy metals (Bruse et al., 1999) and trapping dust particles. parti Green elements can also function as acoustic curtains, while promoting urban biodiversity (flora and fauna), allowing llowing the presence of several species of plants, birds, bees and other beneficial insects (Weiler et al., 2009). Vegetation has an undeniable therapeutic benefit, contributing to the health and well well-being of citizens by enhancing urban spaces.
Property valorization Urban enhancement
Biodiversity
Acoustic protection
Vegetation benefits
Air quality
Therapeutic effect
Climate moderator Stormwater management
Figure 1. Vegetation benefits to the urban context.
2.2 Sustainable urban rehabilitation: the Portuguese example In Portugal, the building construction sector has seen a significant growth in the last decades. Between 1971 and 2001, the number of dwellings has doubled. Simultaneously, Portugal is one of the countries of European Union which has less investment in rehabilitation, needing urgent intervention in the renovation and repair of most of Portuguese buildings. The dimension of urban spaces (villages, towns towns or cities) is three times higher than needed which leads to waste of infrastructures, discontinuity of the urban fabric and urban voids. The most recent town planning policies are directed towards the encouragement urban cont continuity and the preservation off historical parts of cities. In this domain, the new town planning strategies are focused on two main goals, the rehabilitation of consolidated areas and the prese preservation of cultural heritage. For the first time urban rehabilitation is being included as part of planning instruments, such as detailed local plans (Urban Rehabilitation Plan and Heritage Safeguarding Plan). In the U Urban Rehabilitation Plan, sustainability in its tree fundamental aspects (financial, social, cultural and environmental) is defined ed as a principle of urban rehabilitation (Fig. ( 2).
Responsability Coordenation
Subsidiarity
Equity
Fair consideration
Urban Rehabilitation Principles
Intergenerational integration
Sustainability Protection of existing Integration Contracting Figure 2. Sustainability as a principle inciple of Urban Rehabilitation in Portugal.
3 THE IMPROVEMENT OF CITY´S ITY´S IMAGE WITH ECO FAÇADES 3.1Benefits of eco façades There are several justifiable objections to the lack of greenery in cities despite of the benefits referred before. Given that historical areas are characterized by a compact urban fabric, high density constru construction and narrow winding streets, is often impractical impractical to insert green spaces in these areas. Since the 1980s, facade greening began to be used in Europe, particularly in Germany, and is becoming popular all over the world. The use of eco façades in the contemporary city is on the cutting edge of urban n rehabilitation strategies. Eco façades are vertical surfaces which have plants growing on them or integrated within them.. This is why these systems can be part of a greening strategy in dense urban areas, without the use of space at street level, which is i scarce in these cases.
The integration of eco façades, especially in the consolidated urban fabric, contributes to the improvement of the urban environment, qualifying the city´s image, combining new materials with old facades, and creating more pleasant public spaces for the citizens. At the same time eco façades introduce nature into the daily life of citizens (Blanc, 2011a) 2011a), and can be an eco-friendly friendly product (Bianchini et al., 2012). More than a vertical surface with plants, eco façades can be a living livin wall, bringing life, beauty and health to the city with the ability to change its visual characteristics such as its co colour, shape, variety, size or vigour (Figs ( 3-4). These characteristics improve the aesthetic value of urban spaces, which becomes more stimulating for citizens.
Figures 3-4. Living wall of Pacha - The Driver, London, United U Kingdom (Authors, 2011)
3.2Eco façades applications There are several green walls systems on the market, which can be subdivided mainly in two types, the traditional green façades and the new living walls. The concept of eco façades goes further than the typology of green wall system. It refers to innovative ve solutions of integrating vegetation on walls in a sustainable perspective. However, coating buildings surfaces with vegetation is only considered sustainable if there are concerns with environmental, socioeconomic and aesthetic aspects. There are several al applications of eco façades in the urban context, which improve not only the aesthetic of the construction itself, but also the urban surrounding. Eco façades can be used in different urban scales, improving a building façade, a street or an infrastructure. infrastruct The European Environmental Agency building, situated in Copenhagen, is an example of the application of an eco façade in an existing building. The project of architect Johanna Rossbach associates the map of Europe with natural elements organized in chromatic ch scale, emphasizing plants biodiversity and evoking the symbolic value of the building function (Figs ( 5-6). 6). In the case of the recovery of Rue d’Alsace, in Paris, France, it can be understood how the iintegration of a vertical garden in a blank wall of a narrow street can ameliorate the visual co comfort, the natural illumination of the space and the sense of security to the pedestrians who cross this street (Figs 7-8). The bridge wall of Pont Max Juvenal, situated in Aix en Provence, in France, reveals an interesting option of refurbishing an extensive concrete surface of an urban infrastructure with an eco façade. This solution change entirely the image of the place, improving aesthetically the entire urban area in which it is integrated (Figs 9-10). 9
Figures 5-6.. European environment agency building before and after the green façade, Copenhagen, Copenhagen, Denmark (5. EEA, 2012 and 6. Authors, 2010)
Figures 7-8. Integration of a living wall in a street recovery, before and after the intervention,, Rue d’Alsace, Paris, France (Blanc, 2011b). 2011
Figures 9-10. Coverage of a bridge with a living wall, before and after the intervention, Pont Max JuvJu enal, Aix en Provence, France (Blanc, 2012).
4CONCLUSIONS Vegetation can contribute significantly to enhance buildings envelope and be an important strategy of sustainable urban rehabilitation. In the field of urban rehabilitation the application of eco façades is still a new concept. However, its use of eco façades results not only as the presence of green elements in the urban space but also as feature in the city´s sustainability. Eco façades can improve the urban environment through the introduction of vegetation in the city context. On the other hand, they contribute to property valorisation and to the enhancement of the building in which they are integrated and also of the surrounding area. Independently of the element scale and the surface in which they are inserted, eco façades are an important tool of urban rehabilitation. They can improve aesthetically a building façade, a street or an infrastructure giving a new identity to urban spaces, linking “buildings to landscape and culture to nature” (Dunnett et al., 210: 260). However, eco façades can only contribute to the urban environment if they are implemented on a significant scale (AA.VV., 2008b). This reason explains how is important that stakeholders engaged in urban planning policies, instruments and projects, using eco façades and other strategic tools, in order to achieve urban sustainability. 5 ACKNOWLEDGEMENTS This work was developed in the context of a interdisciplinary research project, PTDC/ECM/113922/2009, studying the benefits of green surfaces in buildings, in C-Made / Centre of Materials and Building Technologies in a partnership the School of Agriculture of the Polytechnic Institute of Castelo Branco. REFERENCES AA.VV. 1994. Carta das cidades europeias para a sustentabilidade. Conferência europeia sobre cidades sustentáveis, 27 Maio de 1994. Aalborg, Dinamarca. AA.VV. 2008a. Urban landscapes sostenibilidad. Barcelona : Equipo editorial Monsa, 2008. AA.VV. 2008b. Introduction to Green Walls Technology, Benefits & Design. s.l. : Green Roofs for Healthy Cities, 2008. www.greenroofs.org. Bianchini, Fabricio e Hewage, Kasun. 2012. How "green" are the green roofs? Lifecycle analysis of green roof materials. 2012. pp. 57-65. Vol. 48. Blanc, Patrick. 2011a. Vertical Garden, Patrick Blanc, Resources, Vertical Garden concept. [Online] 2011. http://www.verticalgardenpatrickblanc.com/#/en/resources (accessed 19.12.2011).
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