Materials

Up

The construction industry uses about 6 tonnes of material per person per year in the UK. About 20% of this is for infrastructure and over 50% is for repair and maintenance of the existing building stock (if DIY and other unrecorded works are included). The quarrying of 250-300 million tonnes of material in the UK each year for aggregates, cement and bricks imposes significant environmental costs.

If a sustainable construction project aims to minimise the environmental impact of the proposed development over its design life, then considerable care must be taken to select the most appropriate materials, in terms of the impacts of their manufacture, use and final disposal or recycling.

It is not sufficient to state that materials are "recyclable". Practically all materials fit this description but only a tiny fraction of them actually are recycled. It is important that materials should, as far as is practical, be kept separate and be clearly labelled to facilitate recycling at the end of their useful life. Even this will, of course, not guarantee that they will be recycled but it is the responsibility of everyone involved at every stage of a sustainable construction project to ensure that they have acted to the best of their ability to minimise the current and future impact of the development.

The selection of appropriate materials depends on the financial, environmental and operational performance of competing products, as well as on the criteria set out for the development. For example, there is no point in reducing the materials intensity of the wall design at the expense of its insulating effect, as to do so would lead to a greater environmental impact over the design life of the building. Similarly, it would be unwise to invest the limited resources of a project in expensive gimmicks of limited practical value, such as photovoltaic cells, when the overall impact of the development could be more effectively reduced by investing the money elsewhere.

About 10% of national energy consumption is used in the production and transport of construction products and materials. To reduce this, materials should be sourced as locally as possible and great care should be taken before "thermal mass" is cited as an environmental benefit. A recent large development claimed that the extensive use of concrete throughout the building made it sustainable by providing a large thermal mass, deliberately overlooking the huge embodied energy of the material and associated environmental impacts.

Selection of materials depends on the nature of the development and the aims of the project but with a reasonable amount of care and a pragmatic approach, it is possible to make significant environmental improvements at little or no extra cost.

Further information from materials@sustainableconstruction.co.uk