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Guest blogger Paul Mathers, Programme Manager, Landscape and Regeneration, WRAP

The potential to reuse on site materials in brownfield redevelopment projects has yet to be fully explored. Soil on such sites is often of poor quality or contaminated requires remediation before construction work can begin.

Traditional practice has been to excavate the material, dispose of it to landfill and replace it with imported virgin topsoil. WRAP ‘trailblazer’ trials have shown that, when mixed with existing materials on site, quality compost (produced to the BSI PAS 100 specification) can be used to efficiently and cost effectively manufacture new topsoil. This is a solution that needs to be agreed on at the earliest opportunity before the site is cleared, replacement material is imported, and construction starts.

A series of trials at brownfield developments - including the regeneration of Lambton Cokeworks near Chester-Le-Street and Cronton Colliery in Merseyside – have demonstrated that the use of compost in soil manufacture is not only environmentally advantageous but it’s practical and cost effective too. At Lambton, our research estimated savings in the region of £1.2 million - compared with the alternative of importing topsoil.

And at Cronton Colliery – where quality compost was used as part of a sustainable regeneration programme that turned a brownfield site into an informal country park – the design team saved £19,700 per hectare by choosing to manufacture soil - a saving of 88%.

These are just two examples of what can be achieved by embedding sustainable design policies into building projects. By prioritising the efficient use of materials from the outset of every project, designers can reduce waste, maximise the use of recycled content, use fewer natural resources - and save significant costs.

Trailblazer case studies and compost specification guidelines are available here.