How to … keep down the cost of sustainability

Sustainability is often seen as not economically viable, especially in the wake of the Peabody Trust's now infamous BedZED project, which created environment-friendly housing but went over-budget. But this need not be the case.

To keep the expense of a project under control, it is vital to be clued up on official sustainability standards from the outset and to set clear targets.

Cracking the EcoHomes code
The Housing Corporation requires all its grant-funded housing to achieve a "pass" rating in the EcoHomes benchmark set by research body BRE. This standard has a very flexible scoring method and – given a well-located site – a "good" or "very good" score can be achieved without going beyond what is required by ordinary Building Regulations on energy performance.

The government's Sustainable Buildings Task Group, charged with making recommendations for sustainability for all new and existing public buildings, has called for a new code with higher benchmarks for good practice in energy, water, waste and material. The proposed code would require a best practice standard that included a contribution from renewable energy: solar roof panels, for instance.

It can be advisable to insist on a post-construction EcoHomes assessment, though, which is what English Partnerships does. Levels of sustainability can be significantly different once a project has been completed from those set during planning because of changes during contract stages. Many much-hyped, mainly non-domestic, buildings have been found to be up to three times more wasteful than expected. And houses recently tested as part of the review of Part L of the Building Regulations, for airtightness in construction, were found to be three times less effective than supposed.

Tools for the job
Other specific measures can help rein in costs. Some sustainable infrastructure such as combined heat and power systems – which are up to 98% efficient at converting gas into heat and electricity – even pay for themselves. CHP systems need not add to the cost of a project because they can be outsourced to investors or suppliers.

And recent data prepared for the Department of Trade and Industry and National Trust has demonstrated that on sizeable projects – 500 units or more, say – the supplementary costs of sustainability strategies can be kept to a minimum.

A combined heat and power system need not add to costs because it can be outsourced

The ZEDfactory kit – a database of sustainable construction materials put together by the architect of BedZED – shows that bulk buying can contribute significantly to the sustainability of projects and need not increase costs.

Be sure to set clear objectives during the procurement process for contractors and the supply chain so they do not default to their normal products, believing anything they don't usually use will be overly expensive or will complicate construction.

Champion the cause
One of the best ways to ensure that sustainability remains a guiding goal of the project is to pick a sustainability champion who should impose specific benchmarks and targets on the design team.

They should be aware of any future requirements that could have an impact on the scheme – such as the current review of Part L, which will increase the minimum standard of energy performance by some 20-25% in 18 months' time, well within the lifetime of many current projects.

A sustainability champion should be informed about forthcoming European legislation on environmental liability, toxic substances and waste – all of which could significantly affect construction methods and costs.