The challenges of a embracing a circular economy

Regulatory changes are driving developers to look more closely at material reuse rather than disposal, but old habits are hard to break, finds Kristina Smith

Almost overnight, as the world emerged from Covid, Roy Fishwick noticed a change in attitudes towards reused steel.

“Back in 2016, 2017, I was talking through regulations and reasons to reuse steel sections, but failing to convince people,” recalls the managing director of Cleveland Steel and Tubes. The firm’s core business has always been based on reused steel pipes. “If you go back three years, we sold almost no reuse sections. Now people are asking me about it all the time.”

It is likely that the driver for this uptick in interest was the Greater London Authority’s (GLA’s) requirement for Circular Economy Statements – as part of the planning process for larger developments. The statements specify how a project will reduce waste throughout its life cycle. After four years of engagement and consultation, they went live in March 2022.

“Often, 70 to 80 per cent of a building is concrete. It’s very rare that that gets reused”

Katherine Adams, Reusefully

Katherine Adams, director at Reusefully, a consultancy set up three and a half years ago to advise on reuse in construction, has also noticed the recent shift in attitudes: “Whether it’s a massive change, I don’t know… but there’s a lot more understanding of the topic, and a lot more people talking about it and trying to do a bit more.”

If construction went further with circularity, the impacts would be significant. In its report Closing the Circle, published in October last year, contractor Mace calculates that circularity in London alone could keep 13.8 million tonnes of material, worth £1.25bn, in the construction supply chain over the next 10 years. This would save 11 million tonnes of carbon.

Circularity starts by keeping materials and resources in use for as long as possible, according to the Circular City Centre of the European Investment Bank. For buildings, it means designing in flexibility and adaptability. For infrastructure, it requires investing more in ongoing maintenance and timely repairs. Where buildings or structures must be replaced, a circular approach involves the reuse of the elements making up that building or piece of infrastructure, as close as possible to their source. This might require some remanufacturing – reclaiming materials and components, then refurbishing them and reusing the parts that still have life alongside new ones.

A different issue is recycling, such as using secondary plastic encased within virgin material for a window frame, or melting down scrap steel to process into new sections. Meanwhile, downcycling uses material for a lower-value application, for instance, breaking up concrete to use as fill below a building or road.

There is a tendency in construction to construe recycling as a circular-economy exercise, but this would be misleading, says Eoin Bailey, UK innovation and circular economy lead at Celsa Steel UK. “A circular approach would mean designing products and elements that don’t need to be replaced every so many years, perhaps even moving to a materials-as-a-service model,” says Bailey. In this model, the manufacturer owns the door, window or boiler and rents it out to the user.

Reuse now

To help meet the GLA’s mandate for circularity statements, Reusefully and others carry out predemolition audits that identify which elements of a building can be reused. Working with the developer, Reusefully’s aim, says Adams, is to identify five or six materials that can be realistically prioritised. “If you can make that work, then they can become ‘business as usual’ and you can move forward with other things,” she says.

Steel is perhaps the easiest material to reuse (see box, below). GPE is one of the developers leading the charge on this. For instance, structural steel from the demolition of its City Place House in the City of London has been stored, tested and retained to be used again in its next development on that plot, as well as another at 180 Piccadilly.

“You can demolish a building with no requirement to recover any material. The clock only starts ticking when you’re putting the building up”

Roy Fishwick, Cleveland Steel and Tubes

Other materials that may be reused include carpet and ceiling tiles, and raised access flooring. Timber is not reused as much as it should be, says Adams, and neither are mechanical and electrical elements. This is because timber would have to be carefully removed, graded and tested, which would make it expensive to reuse. Mechanical and electrical items would require repair and/or remanufacture and testing. And old mechanical and electrical items might not align with current standards.

A small number of kitchens and sanitaryware may be reused, and older bricks, but not new ones. The lime mortar used for laying older bricks is easier to remove than modern mortar, meaning that older bricks can be removed intact.

“Often, 70 to 80 per cent of a building is concrete. It’s very rare that that gets reused,” says Adams. Once concrete has been poured (usually on site), it is bonded by a chemical process and there is no way for the constituent parts to be separated and then to remake wet concrete. Reusefully has put forward a proposal with the Concrete Centre, the main development body for the UK concrete sector, to create technical guidance and standards on how precast concrete could be reused.

Asphalt is one of the materials most recycled directly back into the built environment for the same purpose. Relaying it on the road from which it was planed is possible – if the logistics are right. “Asphalt is 100 per cent recyclable, 100 per cent of the time,” says Mark Flint, technical director at FM Conway. “It is the most recycled material on the planet. The bitumen may fail at some point, but aggregate won’t.”

“The reason why [circularity] is a challenge is that the economics we have got are not aligned”

Eoin Bailey, Celsa Steel UK

FM Conway set a new record with Westminster City Council in January, when it used 92 per cent recycled material to resurface in Elmfield Way. The contractor deployed warm mix asphalt, which requires less energy to manufacture, thereby reducing carbon emissions. It then added polymer modified bitumen to the asphalt mix to prolong the life of the road.

National specifications for highways now allow 20 per cent recycled asphalt planings (RAP) in the surface course and 50 per cent in the binder course. Higher proportions may be included by applying for a ‘departure from standard’. This process works well, says Flint, but could be made more efficient were it possible to apply for departures on an annual basis rather than project-by-project.

London-based FM Conway is working with Westminster Council on the Piccadilly Underpass, and with National Highways on the A34. In both cases it is removing RAP from the road, processing it and returning it to the same stretch of road. “It is the first time National Highways and Westminster have achieved full circularity,” says Flint.

Data from two of FM Conway’s plants at Heathrow and Erith illustrate how the use of
RAP has risen. In 2015/16, the average RAP content of asphalt produced from these plants was 19 per cent; in the past year it was 28.2 per cent.

Barriers or excuses?

Adams believes that most of the perceived barriers to reuse and recycling have been overcome or could easily be hurdled.

The steel industry has demonstrated how standards and specifications could be met for reused materials. A technical expertise body, the Steel Construction Institute is producing its second edition of P427, Structural Steel Reuse, which sets out principles for the assessment, testing and design of reused steel. The UK steel industry has also worked with the European committees updating EN 1090, which covers technical requirements for steel structures, to ensure that it allows for the reuse of steel.

“Technically, the issues are all resolved, which means they are resolved in terms of insurers – they are concerned with supplying compliant materials and having them installed in a compliant way,” says Fishwick.

Although demolition audits can be tricky, with varying amounts of information about an existing building available, companies such as Reusefully and Material Index are proving they can be done. Material exchanges – where reusable items can be listed and acquired – have been around for 20 years, says Adams.

“There’s nothing new about them and it’s not rocket science, but you do need critical mass,” she says. “If you want to specify anything from them, you need surety of supply so that it’s less risky.”

Currently, the main barrier to circularity is cost. Dismantling a building carefully takes more time and requires better access and cranage. Fishwick cites the case of a building where the top few storeys were being removed and would have yielded 60 tonnes of reusable steel – but the cost to hire a tower crane to do that would have been an unviable £300,000.

Current construction contracts don’t work with circularity. If contractors are bidding to construct a building where some material will be reused – with exact proportions to be determined after demolition – they must add in cost to cover that additional risk. If more planning authorities were to call for circularity statements, as the GLA has done, that would accelerate change, according to Adams. “It has to come down to policy and planning, although this won’t happen any time soon,” she says.

Changes to the sustainability certification scheme BREEAM, to include indicators for circularity, would help. But although the Building Research Establishment – which provides independent testing, inspection and certification services in the industry – has considered such changes, there is no news on whether they will be implemented.

The push to net-zero emissions could also act against circularity, according to the experts. Decarbonsiation and circularity are often assumed to be two sides of the same coin. But embodied carbon that is lost or saved during demolition or dismantling does not currently count towards the carbon output of new developments. Using software or in-house tools, most big developers and their designers are measuring embodied carbon up to construction handover, as well as operational carbon. “You can demolish a building with no requirement to recover any material. The clock only starts ticking when you’re putting the building up,” says Fishwick.

That is set to change. The Royal Institution of Chartered Surveyors’ second edition of its Whole Life Cost Assessments for the Built Environment was published on 1 July. Changes in this document will mean reuse of buildings and materials can be incentivised, says Bailey. True circularity, though, will require a seismic shift. “The reason why it’s a challenge is that the economics we have got are not aligned,” he says. “The greenhouse gas protocol and net zero is a distraction from the true circular economy. If you decarbonise the current linear process, you will still generate waste. We need to decarbonise the circular economy.”