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Defining ‘Sustainable’ Housing

The Need: ‘Sustainable’ Housing

2.1 Defining ‘Sustainable’ Housing

In broad terms, if something is sustainable it means that it is able to be sustained, that is, to continue indefinitely in its current state or mode of operation. Thus, sustainable

development would be development that was able to continue in a similar manner indefinitely. Referred to more accurately as ecologically sustainable development, to reinforce that the development relies on the environment’s ongoing ability to support it, one of the best-known definitions comes from the 1987 World Commission on

Environment and Development Report Our Common Future (World Commission on Environment and Development, 1987), also known as the Brundtland report, which defines it as:

“….development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” (p. 43)

The Australian Government has defined ecologically sustainable development as:

“…using, conserving and enhancing the community’s resources so that ecological processes, on which life depends, are maintained and the total quality of life, now and in the future, can be increased” (Department of Sustainability, Environment, Water, Population and Communities, 1992).

The concept of sustainability has, since the 1980s, also become increasingly associated with a concept of integrating the economic, social and environmental spheres of human activity, also referred to as the ‘triple bottom line’ (Elkington, 1998). The rationale behind this is that an activity can only be considered truly ‘sustainable’ if due consideration is given to economic viability, social considerations and protection of the environment. In the context of buildings, ‘sustainable’ must encompass consideration of not just

environmental impacts, but also social impacts for builders, neighbours and occupants, and the need to be economically viable during construction but also ongoing operation.

Many and varied attempts to define sustainable housing have been made. The

environmental aspects of sustainability continue to be by far the most common aspect of sustainability to be considered, as compared to the economic or social benefits of a potential construction project (Bourdeau et al., 1998; Essa & Fortune, 2008). This in part explains why the terms ‘sustainable’ and ‘green’ are often used seemingly

interchangeably.

For example, Hoffman and Henn (2008, p. 5) emphasise the environmental dimensions of sustainability in their definition of ‘green’ (or sustainable) building noting it is:

“...a term encompassing strategies, techniques and construction products that are less resource-intensive or pollution-producing than “regular” construction. In some cases, this involves merely ‘doing without’ extra spaces, finishes or appliances. In others, it substitutes a less polluting product for more polluting ones (e.g., low-VOC paint). More integrated strategies reconfigure a space to take advantage of unique site attributes (e.g., facing glass towards the sun path to use natural or

‘passive’ solar heat gain instead of using natural gas or electricity to heat a space) or reconfigure design parameters to take advantage of building system synergies (e.g., downsizing the boiler after extra insulation has been added to the exterior shell)” (Hoffman and Henn, 2008, p.5).

The definition provided by Kats et al. (2003, p1) is more holistic, suggesting that sustainable buildings should be sensitive to:

“…environment; resource & energy consumption; impact on people (quality and healthiness of work environment); financial impact (cost-effectiveness from a full financial cost-return perspective); the world at large (a broader set of issues, such as ground water recharge and global warming, that a

government is typically concerned about).”

Such conceptual definitions, however, provide little practical guidance to assist building designers and contractors to actually design and build such homes. Government and industry bodies have attempted to increase the uptake of more sustainable building practice by fleshing out these definitions, either through regulatory mechanisms or

sustainable building rating tools which articulate specific elements or performance criteria of sustainable buildings. Particularly active in this regard have been the various Green Building Councils which have been established around the world and which have developed voluntary rating tools for various building types. These tools, which were developed both to standardise assessment methods and to reduce the scope for ‘green washing’ by allowing a mechanism for independent verification of sustainability claims, tend to focus on the building designs rather than actual performance. The tools typically provide ‘checklists’ of elements that can be adopted, with a certain number of points to be obtained to achieve a particular rating. These various mechanisms are elaborated on further in section 2.3.

While the various tools and regulatory mechanisms provide somewhat different interpretations of sustainability in a context of buildings, there are numerous areas of commonality. Kats et al. (2003) claim that there is a broad general agreement of the attributes a sustainable building should embody, even if there is still not consensus on their exact weightings, which are typically based on consensus best judgement rather than scientific determination. Of course, it is extremely difficult to prescribe universal criteria or weightings given that different regions will have widely varying climatic zones, locally available materials and the like. For example, conservation of water is more important in countries with highly variable rainfall such as Australia, than it is in places such as Europe.

However, Woolley (2005) notes that few attempts to interpret green building are holistic in their approach, and argues that greater harmonisation and development of common baseline standards and methods is required before promulgating further tools and assessment methods.

Martin and Pears (2005) analysed several of the earlier versions of Australian and

international sustainable housing rating schemes to identify themes and common criteria.

They aggregated the commonly recurring concepts, see Table 1. Additional, less commonly acknowledged criteria, are discussed following the table.

Table 1 – Summary of typical sustainable housing criteria in rating tools (adapted from Martin and Pears, 2005)

Theme Commonly occurring criteria

Land/site  Selecting sites that are less environmentally sensitive or have lower ecological value (for example, selection of brownfield sites over agricultural or purpose-cleared land) and/or sites that do not worsen urban sprawl (i.e. favouring denser urban environments)

 Maintaining and/or planting as high a ratio as possible of either native/localised and/or productive plants (fruits/vegetables) on unbuilt areas of the site

 Reducing the percentage of impermeable surfaces as much as possible to minimise impacts to hydrological cycles

 Reducing the floor plan of the building as much as possible Water  Reducing water consumption per person/per bed space

 Using water conservation fixtures (eg AAA-rated or 3 WELS rated shower heads)

 Collecting rainwater on-site

Energy  Reducing greenhouse gas emissions

 Encouraging the highest possible use of renewable energy

 Ensuring building envelope performance is optimal

 Providing a clothesline/drying space

 Providing energy efficient appliances (such as white goods) or, if not provided, providing education material on energy efficient appliances to occupants

 Reducing energy use for hot water production

 Providing energy efficient lighting

Materials  Choosing building materials from ‘better’ sources; that is, in accordance with relevant publications in that country (eg the Your Home Technical Manual in Australia)

 Using timber from reliable low-impact sources (preferably with

Theme Commonly occurring criteria

Forestry Stewardship Council certification)

Transport  Building within close proximity to facilities (such as convenience store, post office, bank, medical facilities, parks/play areas)

 Ensuring proximity to adequate public transport for travel to work/school

Interior/

indoor

environmental quality

 Using low volatile organic compound (VOC) products such as paints

 Managing combustion products (such as appropriate use of flues)

 Maximising daylighting in the home while avoiding glare and excessive heat

Waste  Providing recycling facilities

 Providing composting facilities

 Reducing sewage production and potable water use (such as waterless sewage systems)

 Treating wastewater on-site or using for landscaping

 Implementing waste management strategies during construction Other  Providing adequate outdoor space (such as patios)

It is apparent from Table 1 that a noticeable gap in the various tools and checklists analysed at that time was any recognition of issues relating to the social (as opposed to environmental) dimension of housing, or exploration of the economic dimension relating a triple bottom line approach. This narrow interpretation of ‘sustainable’ to emphasise the environmental dimension of sustainability, while neglecting the social and economic aspects, remains a limitation of the majority of sustainable building definitions and approaches. A building with minimal environmental impact but that later adversely

impacted the health of future occupants can hardly be considered to be a truly sustainable proposition. Similarly, in the case of housing in Australia, affordability is also regularly raised as an issue of concern from a social equity perspective (Senate Select Committee on Housing Affordability, 2008; Housing Industry Association, 2008a; Australian Bureau of Statistics, 2010a).

The Your Home Technical Manual (Reardon et al., 2008) is an exception to the above observation, addressing a number of social considerations associated with sustainable housing, which it notes include:

 Adaptability – the need to design houses which are flexible and can respond to changing needs of occupants, without complicated and costly alterations. This may include features such as home offices or designing a larger family home that can be easily divided into smaller units when children move away. In addition, as much as possible, houses should be designed to be ‘universal’, meaning they can be used by as many people as possible without the need for specialisation, and ‘accessible’ to allow for access and mobility (including by disabled persons); or at least able to be adapted if required. This includes features such as avoiding stairs, having wide openings, and shelves and benches at an appropriate height (Palmer & Ward, 2011);

 Safety – a significant proportion of accidents and injuries occur in the home. Safety considerations such as unobstructed access, guarding, slip resistant surfaces, electrical safety, night lighting, hot water system settings, avoiding level changes and the like, should be paramount during design and retrofitting (Woodcock et al., 2011);

and

 Security – helping to prevent crime by facilitating surveillance through window

placement; installation of appropriate locks, screens, alarms; controlling access, such as with fences or gardens; and designing outdoor spaces to foster a sense of

communality (Woodcock et al., 2011).

Other less commonly identified sustainability criteria in the various tools include designing for local environmental risks. For example, in many parts of Australia, it is important to design a home that can withstand bushfires, as was tragically reinforced during the major bushfires in Victoria in early 2009 (Building Commission, 2010). This may include

considerations such as a fire resistant building envelope, selection of appropriate vegetation for landscaping, provision of evacuation paths and defensible spaces and selection of non-combustible materials (Prelgauskas, 2011). In future, given expectations of rising ocean levels and increased extreme weather events associated with climate change, designing homes in appropriate locations and that are better able to withstand extreme climatic conditions could also be considered to be an important form of

insurance.

The above discussion lists a range of points that can be considered when designing a sustainable house. However, it is important to stress that a ‘sustainable’ building should be holistic in its approach, with its focus not confined to individual factors such as energy, water or indoor air quality, in isolation (such as ‘passive solar’ buildings). The

interdependence of, and potential for synergies between, sustainable features should be

understood. It is also critical that sustainability features should be fully integrated with the design, rather than a series of ‘tack-ons’, or what Barnett and Browning (2007) refer to as a ‘50 stupid things’, piecemeal approach to building. This allows sustainable buildings to compete on cost and to avoid sustainability features being removed during cost-cutting exercises (Kats et al., 2003).

As an example, Rocky Mountain Institute et al. (1998) cite a New Zealand developer who used to offer a package of ‘green specification’ options including double-glazed windows, heat-recovery ventilation, energy conservation features, water-efficient plumbing and solar hot water, adding about $10,000 in cost to the original $220,000 standard price.

However, because these features were not implemented in an integrated manner, the ability to realise potential cost-savings such as the ability to downsize or eliminate mechanical systems, was lost.