Maxine Perella finds out how the construction industry is adopting a circular approach for its materials and waste
Collectively, the construction, demolition and excavation sectors are the largest contributors of waste in the UK. It is estimated that together they generate around 80 million tonnes of waste every year. According to Wrap, the body that advises on waste and resource issues, managing and disposing of unwanted materials costs the construction industry the equivalent of 30% of pre-tax profits.
Although good progress has been made by the sector in terms of landfill diversion, with recycling rates at around 90%, a stronger business case is now emerging to push construction waste not just up the waste hierarchy, but beyond it.
Going in circles
One approach gaining traction is to apply the circular economy model to construction. This aspires to design waste out of not just the construction process, but the entire lifecycle of a building. Work undertaken by Wrap indicates that, in the built environment, lifetime maintenance and management costs are around five times those of construction. The adoption of lifecycle thinking - such as designing for deconstruction so that components and materials can be disassembled, reused or reassembled - can not only help reduce these costs over the long-term, but retain the resource value embedded in structures.
Such a fundamental rethink represents a challenging proposition but, as interest grows in the circular economy, moves are being made to examine how feasible this shift is, led in part by the UK Contractors Group (UKCG). Last year, it published a beginner's guide to circular principles in sustainable construction. Simon Nathan, head of policy at UKCG, believes the concept is likely to have "profound effects" on the delivery of construction projects. "While UKCG have other existing workstreams on waste and materials, it was considered that a working group on the circular economy was needed to examine the wider issues," he says.
The group is seeking to define what the circular economy means for UKCG members and to identify opportunities. In terms of immediate priorities, the UKCG is looking to establish current practices and develop training materials to engage members, as well as their suppliers and clients, to encourage uptake. Asked where he sees greatest appetite for circular economy thinking in the supply chain, Nathan replies: "There are isolated examples, with construction industry suppliers beginning to develop and offer circular economy solutions and service offerings that respond to this agenda. To make it happen it requires the buy-in of all parties."
One contractor keen to push forward on this agenda is Balfour Beatty Construction Services UK. The company's director of sustainability, Paul Toyne, says it is still "early days" for the industry. "If you think about all the different components you find in buildings, companies are looking at leaner ways of manufacturing their products - but that doesn't necessarily consider the afterlife use," he says.
Toyne maintains that, for a circular economy to work in construction, contractors need to have confidence that the products or materials they use, both in the building frame and the internal fixtures, will retain their value when the time comes for deconstruction or adaptation - often several decades later.
"If you've got materials that are embedded in the building ... we don't know what the value of those materials might be in 50 or 60 years' time," Toyne says. "The effort that goes into designing buildings to deconstruct, or to take those elements out, is handicapped by the fact we can't predict the future."
Balfour Beatty's first venture to deliver a building capable of being deconstructed can be viewed at its flagship project, St James's Market in central London. The company's commercial redevelopment for the Crown Estate incorporates into the build, timber, slate and stone sourced from the client's forests and quarries. At the same time, waste minimisation techniques, such as off-site prefabrication, salvage and reinstallation activities are being pursued.
Balfour Beatty is also employing building information modelling (BIM) to store component details, including maintenance and ownership.
Internally the contractor has identified 16 potential opportunities for circular construction, four of which it has prioritised. These centre on:
- design - standardisation, design for deconstruction, easy repair/life extension, flexibility and biomimicry;
- waste - waste as a resource, zero waste, research and development, new materials and manufacture to design;
- energy innovation - energy efficiency, not just in terms of energy use in operation, but in build and decommissioning; and
- dematerialisation - reviewing what is built and how it is built.
On a wider level, one development that could provide an industry framework for more circular buildings is RE-Fab - a protocol that looks to reduce whole-life costs through increased use of adaptation and refurbishment. The organisation behind this concept, the Alliance for Sustainable Building Products (ASBP), hopes it will enable new models of financing, such as product leasing.
So far, RE-Fab has received funding from Innovate UK to undertake a series of feasibility studies and is now looking to take its work into the wider community.
"We want to create a framework for better decision making - we are talking about reframing the whole way building [work] is done," says Gary Newman, executive chair at ASBP. The principles of RE-Fab have already been reflected in Chobham Manor Marketing Suite, a demountable showroom at the Queen Elizabeth Olympic Park. Developed by Suitebox and ES Global, the building uses standard construction materials and components that have been adapted to suit the requirements of reuse.
Chobham Manor also employs a novel on-ground foundation system of steel padfeet to save on the cost of complex foundations and slash onsite build time. Using this approach, buildings can be constructed with a design life of between six months and 60 years. Graham Hilton, director at ASBP and co-founder of RE-Fab, hopes the project will challenge the view that buildings are permanent, fixed structures. They can and should be more fluid, he says, describing demountable builds as "Lego for adults".
More emerging best practice should start to appear with Innovate UK's latest funding competition - it is investing up to £4 million in collaborative research and development projects that lead to better whole-life performance of buildings. The government-sponsored agency, formerly the Technology Strategy Board, is interested in proposals that can either show evidence of, or improve, a building's whole-life performance or stimulate customers to procure and manage better solutions - this might involve product leasing or performance-based contracts.
Dr Mike Pitts, lead specialist for sustainability at Innovate UK, believes construction represents one of the biggest opportunities in the circular economy due to how much material it consumes. "How can we get a building to have lower running costs, lower impacts and better performance over its lifecycle?" he asks.
Much of this links back to design. Here, building material suppliers have a key a role to play, according to Charlie Law, founder of Sustainable Construction Solutions. "Material suppliers have to come up with solutions that can be taken down and are demountable because a lot of what they design at the moment goes up and is fixed in place," he says.
Some of the solutions mooted appear simple. These include bolted rather than welded connections for steel beams, and "glueless" substitutes for traditional brick-bonding agents of cement and sand. Although there are a few products on the market designed with disassembly in mind, such as demountable ceilings and leasable carpet tiles, these are geared more towards internal fittings. "There's only a limited range of materials available that are able to be used in a circular way at the moment. Questions need to be asked by designers and clients to push industry forward to develop these solutions," Law says.
A move away from composite structures such as foam insulated metal panels that are difficult to separate out for recovery or reuse might also be beneficial. But whether you design for durability, deconstruction or adaptation, much depends on the intended use of the building, the tenancy and the land it sits on, as well as the governance and legal structures in place when preparations are made for materials to be reclaimed at the end of their use phase.
Toyne at Balfour Beatty believes the most sustainable building in terms of its foundations is one that is built to last but with adaptation built in. "That functionality, so that a building's use can change over time, is key. That would help in terms of its longevity and that's a fundamental challenge back to designers."
Echoing this, Law says that perceptions need to be changed on the future financing of this type of property. "Investors think they own the bricks and mortar in a building ... but the asset is the space. You don't need to own the bits that make up that space; it's the space itself that you own. It's trying to work out how those contractual agreements work over the long term, and how the building changes hands over that lifetime."
Here, the UK could learn from the Netherlands, which is pioneering some interesting work in the ownership of the materials in buildings.
Dutch firm Delta Development Group sees buildings as "material banks" and believes developers should start tapping into the residual value of materials tied up in commercial real estate. By taking a more inclusive supply chain approach to material specification, the company has created supplier material lease agreements. This means that, in effect, large parts of the buildings that Delta develops are now owned by individual suppliers. This has led to several benefits, including lower costs for changing interiors or workplaces, lower rates for tenants and a reduction in real estate investment risk.
Another circular exemplar is Villa Welpeloo in the Enschede region of the Netherlands. It is a house and art studio designed and constructed by Superuse Studios. It is notable not just because 60% of the house is built from locally salvaged materials, but because they were sourced through the use of satellite technology. The agency employs Google Earth to identify waste stock in nearby industrial zones so that it can access high-quality materials cost-effectively.
Superuse Studios has scaled up its materials recovery strategy and has created an open-source online tool called Harvestmap.org. Visitors to the site can identify large quantities of waste materials, including plastics, wood, metals and chemicals, that are available for local collection. The work of Superuse has been picked up by the Ellen MacArthur Foundation as having significance for creating circular economies in buildings through the optimisation of material flows.
Meanwhile, the Dutch-based Circle Economy Institute has developed ACT (assessing circular trade-offs), a tool for assessing end-of-life scenarios and has done some initial application work in the construction sector. It looked at options from the downcycling of construction and demolition waste for road-based aggregates to the reuse of concrete blocks to identify the best economic solution for a specific situation.
It found that, from a circular perspective, recycling is still a form of value destruction since all the embodied energy is wasted. As concrete is responsible for 25% of energy use in the building and demolition sector in the Netherlands, reusing concrete blocks can reduce that impact and save significantly on production costs.
In the UK, there are still many barriers to address. UKCG's Nathan cites a lack of knowledge, institutionalised mind-sets, the perception that circular products may be inferior, insurance issues, and the need to address supply and demand cycles.
It is a view shared by Law, who believes the construction industry is some way off making that shift: "In the next few years I would hope to see a lot more people thinking seriously about how they can make their products more circular and see some of these ideas incorporated into buildings. It's definitely getting some traction out there. I think everyone can see the benefits of it - material suppliers are seeing it because they can see potential for getting their raw materials back and, if they've got issues with future security of supply, this is a way they can guarantee that."
He adds that customers will stand to gain too. "There are benefits for the client especially around things like the service type model agreement. It could be that they end up paying less for the installation of the product and that the actual cost of [it] ends up in the operational budget. The capital expenditure for a building becomes less, the operational expenditure might be a bit more ... but that means they've got a building that is always going to function."
Maxine Perella is a freelance journalist.