For those who are not following on Twitter or have otherwise missed it for some reason, this week I am battling it out online in the inaugural Saint Gobain Debate. I am proposing the motion that: ‘There is no useful definition of what a sustainable building is’, which is being opposed by Jon Chadwick of Associated Architects.

You can follow the debate, contribute and vote here.

Otherwise here is a copy of my opening argument:

There is no useful definition of what a sustainable building is.

In order to have a definition of what a ‘sustainable building’ is we must first have a definition for ‘sustainable’. A widely recognised definition is that of ‘sustainable development’ taken from the Brundtland Commission report Our Common Future:

“Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”

In this context however, ‘development’ is human development, not the bricks and mortar development of real estate. The Brundtland Definition is big picture stuff and cannot so easily be applied to individual buildings. Nevertheless, we should respect the principle. All human activity has impacts, construction and operation of buildings particularly so. We must certainly work hard to deliver functional and cost effective buildings at the lowest possible impact.

We have at our disposal numerous means of assessing impacts. BREEAM, the BRE Environmental Assessment Method, is probably the most comprehensive. BREEAM has been refined over many years to assess a building’s impacts in: energy and water use, health and wellbeing, pollution, transport, materials, waste, ecology and management. However, even this comprehensive checklist of impacts does not make BREEAM a measure of how sustainable the finished building might be.

Whilst BREEAM is one of the better checklists, we often see sustainable credentials claimed on much more flimsy grounds, such as the Passivhaus Standard or even Building Regulations SBEM. Referring to these limited issue assessments as making a building sustainable misleads the public and potential purchasers. It creates belief that buildings can magically become sustainable through the addition technology fixes to address headline issues like carbon emission.

That road leads to Eco-Bling. It is now common to see specious claims to sustainability made on the grounds of urban wind power or city centre biomass heating.

Focusing on any limited range of issues, without considering the entire system within which buildings exist, can lead to perversely un-sustainable outcomes. The principal competitor to BREEAM is LEED, ‘Leadership in Energy & Environmental Design’. Despite its arresting name, recent research by Professor John Schofield in the USA reveals that a high LEED score has no statistically significant impact on primary fuel consumption, nor carbon emissions associated with a building.

If an internationally recognised ‘sustainability’ rating system has no discernible impact on its eponymous objectives, there can be no justification for any claim on lesser grounds.

So, what is the alternative? The Oxford English Dictionary defines ‘sustainable’ as “to be capable of enduring”. Thus, before labelling a building ‘sustainable’, we must consider its useful longevity. We need to have some measure of the period over which the impacts will amortise. In other words, we need to assess the quality of the design and its appeal to society. Whether it is best fitted to the occupants’ needs or is simply a money spinner for a developer. Most importantly, we need to assess whether the design is sufficiently flexible for a building to endure through numerous incarnations.

I suggest that some of the most sustainable buildings in UK cities today are Georgian terraced houses. The Georgian design ideals of proportion, space and light ensured that many buildings were valued by subsequent generations. Not only for their beauty. These buildings have proven sufficiently flexible to be reincarnated as shops, offices, multiple dwellings, museums and many other uses. Far from conforming to a modern checklist approach to sustainability, these buildings were simply designed thoughtfully with their future users in mind.

I believe that this is the key to sustainable buildings. A sustainable building is one that its occupants will want to go on occupying. A sustainable building is one that enables its occupants to be more comfortable and more productive, as well as consuming less energy and less resources. Sustainable buildings bring business enhancing performance benefits to commercial occupiers. How can any building be sustainable that does not contribute to the social development of its occupants and its neighbours?

Without assessing longevity, social contribution and business performance benefits equally with impacts and costs, we cannot make any judgements about a building’s real worth.

At least for now, there truly is no useful definition of what a sustainable building is!