Off-site innovation

Off-site construction systems (OSC) may reduce on-site waste by up to 90 per cent, according to a series of studies commissioned by waste and Resources Action Programme (WRAP).

The construction industry is beginning to embrace OSC methods, resulting in better prediction, quality control as well as health and safety. The new case studies, undertaken by Mtech, consultants for OSC, suggest that at least five different OSC systems could also significantly improve waste management.

Light steel frame construction of wall panels and floor cassettes can reduce wasted materials by up to 70 per cent compared with traditional construction and the small amount of waste produced can be re-used or recycled.

Modular construction moves nearly all the manufacturing activity to within the factory. The controlled environment reduces the risk of producing waste through errors or accidents and wastage on site is reduced by 70 to 90 percent.

Precast concrete for structural and ornamental elements is the most widely-used OSC product. It eliminates the need for temporary works such as scaffolding and supports and allows manufacturers to identify faults in the design stage. Waste generated on site is reduced by up to 50 percent.

Volumetric pods, or small, factory-made units fully furnished with furniture and bathroom or kitchen appliances, are commonly used on building sites with significant repetition of design. By producing the units in a controlled environment, production times are improved and waste is reduced by up to 50 percent.

Timber frames to replace floor cassettes and wall panels can be mass produced in a controlled environment. The technique improves quality control and reduces the amount of waste produced on site by up to 40 percent.

These various OSC methods could prove very useful to the construction industry as it endeavours to meet the government's target of cutting waste in half by 2012. As Mervyn Jones, Programme Manager for Waste Minimisation and Management at WRAP observes: "These five studies provide practical examples of how and where each system can really save on waste. The results are extremely positive and show that a real difference can be achieved."