Sustainable construction methods

The Future: Making Buildings Greener

A great deal of modern building practice has waste 'built-in'. For example, it is cheaper to over order materials and then throw them away than risk keeping contractors idle on site; for this reason, 30% of the expensively produced, new materials used in a typical construction are thrown away.

Sustainable construction

Engineers like Halcrow Yolles' Tai Hollingsbee have spent many years investigating how our buildings and construction practices could be made more sustainable. They believe that we need to see a fundamental shift in the way buildings are designed:

• Many tall buildings are still clad in un-shielded single glazing – which causes over-heating in summer and provides poor insulation in winter
• Poor placement of windows – and deep, square floorplans, mean we still rely on artificial lighting during the day
• Large commercial buildings create vast amounts of heat, most of which is simply lost to the atmosphere. A combined heat and power system would allow this heat to be recycled and used to warm local houses for example

Over the past decade, engineers are rediscovering ancient techniques in heat and air-flow management that have largely been undermined by the advent of air-conditioning. These include creating 'heat sinks' that use cooler night air to reduce the temperature of incoming air during the day.

Barriers to sustainable construction

Although the sustainability imperative is gaining in importance, there are still major barriers preventing this 'new style' engineering practice becoming the norm.

Chief amongst these is economic: due to the extra consideration needed to design and build sustainably, the most efficient buildings cost more. Although the long term running costs should be (far) lower, for developers this currently is less of an incentive. Moves for buildings to be rated according to their on-going performance may change this.

Other factors are social but no less important; for example, we are used to the instant response of air-conditioning and central heating; persuading people to wear jumpers in offices in winter will require a major sociological shift. Similarly, in many developing nations, air-conditioning is seen not just as a necessity but as a status symbol.

As with so many ‘green issues’, engineers have the means to make our built environment more efficient, but need the support of society to do so.