Recycling is rarely the first thing people think of when they see an old block of council flats being knocked down. But for many demolition contractors, it is becoming a fundamental part of their work.
One such company is John F Hunt, which is in the process of knocking down four tower blocks in east London in one of the first phases of the £600m Canning Town and Custom House Regeneration Programme. As part of the project’s environmental requirements, all of the rubble and debris from the demolition will be sorted and recycled on-site – and the recycled materials are being put to immediate use.
As part of the project’s environmental requirements, all of the rubble and debris from the demolition will be sorted and recycled on-site
Hardcore from the demolished towers is passed through a concrete crusher to process it to the required grade, in this case 6F2 material. It is then spread around the site in a thick blanket to provide a working platform, which will then be used by the piling rigs needed to construct foundations for the structures replacing the tower blocks.
The recycling aspect of such a project begins long before this point. As part of its Site Waste Management Plan and to comply with its ISO 14001 procedures, John F Hunt works out a demolition recovery index at the tender stage of a development. This gives the company a rough estimate of how much material it expects to recycle on the scheme, complete with target percentages to aim for.
The result is that 100% of the concrete, brick and metal arising from the demolition is recycled. The metal is loaded into skips and transferred to scrap merchants for reprocessing, while the concrete is either sold back to the construction industry or, as in the case of the firm’s Canning Town project, utilised on-site for the benefit of subsequent works.
Where in the past the client had to pay for importing such material to install a mat for the rig, we now process this material on-site
John F Hunt managing director John Hall says: “This is now becoming the need on most of our projects. Where in the past the client had to pay for importing such material to install a mat for the rig, we now process this material on-site. This has considerably reduced lorry movements on the road, leading to less traffic and reduced CO2 emissions, and it also saves a lot of material and financial resources.”
Hall adds that on an average full demolition project typically including asbestos removal and soft strip, the company is able to achieve a recycling percentage of up to 99% by weight. This is partly driven by ambitious client targets, such as those of Newham Borough Council, which is overseeing the Canning Town development.
A council spokesman says: “John F Hunt is a contractor experienced in demolition and committed to recycling, reflecting Newham Council’s commitment to increasing recycling rates. This aspect is hugely important to the council and can be seen in the contract we have with John F Hunt.
“This places a requirement on the contractor to provide evidence of the quantity of materials that have been recycled once the project is complete. For example, crushed concrete could be used for hardcore, slabs or even a road construction base.”
Although this emergent aspect of its business is not without its costs and challenges, John F Hunt sees the long-term benefits of its recycling commitment.
Hall says: “There have been a few challenges in the past where not many parties associated with these projects were aware of the recycling process. Now all the major contractors are aware of how the process works. This has opened new avenues, and allowed many companies to generate employment and revenue through waste recycling.
“There are additional costs associated with this. But by recycling, we are saving time for our clients, using fewer man-hours and ultimately saving valuable material and financial resources in the best interest of the environment.”