Sustainable architecture uses building methods that people can go on using with the skills and resources available to them. It defines an approach that seeks to bridge the gap between the declining viability of traditional solutions and the inaccessibility of many modern alternatives. Sustainable architecture is context-specific. It also implies an approach that in a development context goes beyond the project phase. Sustainable architecture recognizes that while the product may wear out over time, the process remains. This process can then be repeated without resort to major external inputs. Sustainable architecture brings together at least five key characteristics: (a) environmental sustainability – avoids depletion of natural resources and contamination of the environment; (b) technical sustainability – uses skills which can be shared and locally accessible tools; (c) financial sustainability– works with accessible financial resources and/or traded services and expertise; (d) organizational sustainability – brings together different stakeholders without, for example, the need to call on outside expertise; and (e) social sustainability – ensures that the overall process and product fit within the needs of society and satisfies them.
Sustainable architecture: (1) makes substantial use of locally available materials and local means of transport; (2) uses resources that are available in sufficient quantity to satisfy a general demand and not damage the environment; (3) only uses equipment that is easily available; (4) uses skills that can be realistically developed in the community; (5) can be afforded within the local socio-economic context; (6) produces a durable result; (7) responds to and resists the effects of the local climate; (8) and can be replicated by the local community.
Many successful examples of sustainable architecture already exist and match these criteria. Amongst the many natural building techniques and styles are: straw-bale, cob, light clay, timber framing, log construction, cord wood, thatch, earth bags, rammed earth, cob ovens, clay infill, sustainable design and building, photovoltaics, plasters and finishes, sacred space, bamboo construction, living roofs, baubiologie, waste treatment systems, sites, earth sculpture, engineered building materials and other natural, bio/agri-based and recycled building materials, feng shui, permaculture, and eco-villages.
Traditional planning and building methods were often good examples of sustainable architecture in their time, and represented good uses of local resources matched with local skills. But factors such as demographic growth, shifts from rural to urban areas, natural and human-made resource depletion, and significant changes in expectations and lifestyles, all combine in their various ways to erode the viability of traditional approaches to shelter provision. Local approaches to achieving shelter that have in many instances been sustainable over many centuries are now unable to cope with the sheer concentration of people who require housing or lack of local resources. Taken together, all these changes mean that a building method that worked well in the past in its given context may have now become difficult to afford, build and maintain, and it may no longer meet the desired requirement of the family or community. In this environment, new solutions and approaches that seem genuinely sustainable are hard to find. Where they exist, they need to be encourages to keep pace with growing needs.
The Gaia Group (architects for building biology) pioneers ecological house design, housing developments, and space for human habitation in general.
The "Woodless Construction" Programme in West Africa has gradually introduced the skills to ensure technical and organization sustainability for the construction of vault and dome roofed buildings using simple, hand-made unstabilized mud bricks. Six years after construction began on Ecolonia, a project of 100 demonstration houses in the Dutch town of Alphen aan de Rijn, non-toxic, chalk-composite building blocks, solar boilers and roof-mounted heaters, internal warm walls and natural ventilation systems have quickly become market-place items. But other features like the vegetation-covered roofs, which cost more than traditional tiles roofs and have no added insulation value, are unlikely to gain commercial popularity.
The new Environmental Studies Center (ESC) at Oberlin College, Ohio was designed with the following criteria: (1) discharged no wastewater; (2) generated more electricity than it used; (3) used no materials know to be carcinogenic, mutagenic or endocrine disrupters; (4) used energy and materials with great efficiency; (5) promoted competence with environmental technologies; (6) used products and materials grown or manufactured sustainably; (7) was landscaped to promote biological diversity; (8) promoted analytical skill in assessing full costs over the lifetime of the building; (9) promoted ecological competence and mindfulness of place; and (10) became in its design and operations, genuinely pedagogical; and met rigorous requirements for full-cost accounting.
Green building strategies used in the following areas were:
[Materials Selection]
: The building was designed to use materials with low embodied fossil energy, with preference given to those that were grown or produced locally. Materials that are not biodegradable are considered "products of service" and are leased from the manufacturer to be eventually returned and remanufactured into a new product.
[Energy Efficiency]
: The ESC is designed to be a net energy exporter. Advanced energy modelling techniques have allowed the design team to significantly reduce the building's energy load. The building employs both passive and active solar techniques. New non-toxic PV panels on the southward curving main roof will generate electrical power. Passive solar design strategies include southern exposure for winter heat gain and protective overhanging eaves on the southern facade to protect the building's interior from the high summer sun. Heat pumps will transfer heat from southern to northern spaces as necessary. In addition, geothermal wells will allow the building to benefit from stable underground temperatures. The building's HVAC system will give individual spaces control over their own heating and cooling. Data panels in the entry atrium will display the building's energy use, water use and greenhouse gas emissions.
[Indoor Air Quality]
: Fresh air will be delivered throughout the building via an underfloor plenum.
[Water Use and Wastewater Recycling]
: The Living Machine contained within the building will eliminate the need for chemical treatment of wastewater. Modelled after nature's wetlands, the Living Machine's system of purification tanks holds a remarkable diversity of plants, algae, snails, fish and micro-organisms which effectively remove bacteria from the building's sewage and wastewater. The tanks will eventually empty into an exterior pond where grey water will then be recycled back into the building's toilets.