Tightening the belt on construction waste requires close scrutiny from the outset
Footprint spent the day in Oxford last Wednesday at a three-part workshop organised by environmental charity BioRegional, comprised of a breakfast workshop about the Olympic Park, a seminar with case studies, and a visit to Oxford Wood Recycling. The breakfast event, which was part funded by the European Regional Development Fund (ERDF) and hosted by solicitors Blake Lapthorn, attracted almost thirty people for an early 7:30 am start: a mix of construction industry professionals, including civil and mechanical engineers, specialist consultants, and local councillors. The only architect present was speaker Gary Wilburn of Southampton-based HPW Architecture. Clearly this subject still requires awareness-raising in the profession.
Main speaker Jonathan Essex, BioRegional’s sustainable construction manager, reflected on his experience dealing with construction waste on the London 2012 Olympic Park project. Jonathan highlighted the major challenges as team motivation, storage, health and safety, materials liability and quality control. As a starting point, clarification of terminology is critical. Reclamation, reuse, recycling and recovery (downcycling) were identified as separate processes requiring separate targets. Reclamation and reuse allow a greater carbon reduction over the processing requirements of recycling and recovering, hence maximising these was a major concern. This strategy was in accordance with the now legal obligations of DEFRA’s Waste Hierarchy released in March 2011 (below).
The construction waste figures of the Olympic Park present an interesting picture. The site demolition phase exceeded its target of 90% recycle and reuse. From the 220 buildings demolished on the site, over 98% of the material was diverted from landfill – a tonnage of over 400,000. However, despite this significant achievement at the outset, only 0.5% was actually reused. There is a long way to go on this front. Each material type had its own story; an example of minor timber reuse was the salvage of a timber truss, although its final whereabouts were unknown.
Similarly, brick reclamation was a missed opportunity. Of the 1.35 million bricks deemed reusable, a demolition-led approach meant only 0.4 million bricks were reclaimed for reuse. Examples such as this account for the disparity between recycling and reuse rates; time constraints always favour the former and reuse requires more forward planning which has yet to make its way into practice.. A greater reuse success story is the reclamation of the steel portal frame buildings on the site – seven were flat-packed as whole buildings including cladding and sold to a specialist company. Unlike the case of the bricks, the time taken over dismantling was deemed worthwhile because of the value of a whole building product.
Reuse was particularly hindered by the diminishing local reclamation and salvage industry which is not geared for the types of materials which could be reclaimed from the Olympic Park’s post-industrial landscape. Indeed the wider reuse supply chain lacks resources, from reclamation workers to storage to end-users. On-site storage was at a premium – the large volumes of soil and aggregates required at the park meant storage could only be justified for what would be recycled and recovered on the site.
As for waste during the construction process, wheelie bins at workstations, an engaged workforce and a cross-contamination penalty system ensured on-site segregation was successful. Materials were then inspected and where possible reused elsewhere on site. The construction waste amount of 28,971 tonnes was easier to handle when compared to demolition waste.
Matching offer to need was the big reuse challenge at the Olympic Park, but there are some success stories to tell. Excess insulation was donated to HEET, a not-for-profit organisation that installs free loft insulation. Similarly, good timing allowed a collaboration with the local Arcola Theatre, who were in desperate need of resources for their renovation. The Olympics example demonstrates that the greatest success stories derive from community engagement combined with awareness of what is available on site. An inventory of nearby projects enables demand to be identified, but this requires resources and advance planning.
At the follow on seminar, Nicole Lazarus, also of BioRegional, gave a glimpse into lessons of community engagement from the ongoing Bicester eco-town project, where the first phase of 400 homes from the masterplan is due to start on site in October. Having already involved the community in a number of demonstration projects, there are aspirations for an on-site reuse centre, which is attracting a wide buy-in. In later stages, community involvement will be deeper still, with some homes available under a “self-finishing initiative”.
Gary Wilburn of HPW Architecture gave some insight into his experience of ‘Creative use of waste in the Design Process’. He argued that in the current professional arena, where many firms claim sustainability expertise, underlining a creative waste strategy when pitching to clients might give that competitive edge. However, the Olympics example demonstrates the creative limitations caused by issues such as health and safety: the reuse of logs for brown roof habitats on the Media Centre took three and a half months of paperwork just to move them from A to B.
The event concluded with a tour around Oxford Wood Recycling centre, by project co-founder Richard Snow, who explained that the project deals mostly with reuse and recovery (downcycling) than recycling. The project’s mission is two-fold: to salvage wood in the greater area around Oxford and to encourage and support re-employment in the area, giving it recognised Social Enterprise status.
A modest operation, the centre itself is a 2000 square foot industrial shed based in Milton Park several miles south of Oxford. Its caged trucks return three collections a day, although 89% of this material is rejected and ferried straight out to timber recycling points. On arrival at the centre, the material is weighed and audited for report back to the supplier and then is de-nailed and sorted. A range of products from sawn timber to ex-scaffold boards are then priced at 60 per cent of the going market rate.
Currently Oxford Wood Recycling is operating at capacity and lacks space to increase collection, confirming the expansion needs of the UK’s fledgling reclamation industry also apparent during BioRegional’s experience at the Olympic Park.
In summary, the event’s focus on reuse sparked an intriguing discussion: can architects feasibly embrace a ‘Lego-style’ of reusable architecture, especially in the context of a temporary, high capacity event such as the Olympics? Could the sustainable Olympics of the future actually be housed in a ‘travelling circus’ of demountable structures? The concept of reuse clearly as a long way to go.
For more on reuse and recycling, see the full BioRegional report.