If only 10% of construction materials are currently not recycled, that鈥檚 probably because there isn鈥檛 much of it that can practically be recovered. Maybe so, but the Department for the Environment, Food & Rural Affairs (Defra) has a Waste Prevention Programme that envisages persuading the industry to go beyond crushing waste materials for aggregates or hardcore.
It looks to a world in which buildings are designed to be disassembled and their components reused, and later this year Defra will publish a 鈥榬oadmap鈥� towards achieving zero avoidable construction waste by 2050.
This is all part of the drive to get the UK to 鈥榥et zero carbon emissions鈥� by mid-century, a policy that is making demands on many industries to rethink time-honoured ways of working.
Defra says its aim is to reduce construction waste and increase the reuse of materials at their highest value, which means 鈥渄esigning buildings for adaptability and deconstruction, increased reuse of components, use of materials that can be reused and recycled, and improved demolition systems鈥�.听
It sees the industry鈥檚 problem as partly one of over-consumption. According to Defra鈥檚 waste prevention programme, construction uses more resources than any other industrial sector and is also the largest generator of waste, at more than 60 million tonnes of non-hazardous waste each year in England alone.
On top of that, Defra says 15% of materials supplied are wasted during the construction process and around 50,000 buildings are demolished annually. And although it concedes that 90% of construction waste is recycled or recovered, it seems this is not enough.
As it explains: 鈥淢uch of this is 鈥榙owncycling鈥欌�� for instance, when waste is used to fill holes on sites or is crushed into aggregate, which is inefficient in terms of the energy used to create these materials.鈥�
And for anyone who gives little thought to how construction materials are made, it adds: 鈥渢he manufacture of construction materials is responsible for 11% of global CO2听emissions鈥�. At least 25% (and in some cases up to 60%) of a building鈥檚 whole life emissions derive from its materials, says Defra.
Defra believes emissions could be reduced by nearly 80 million tonnes of CO2听between 2023 and 2032 if ways were found to reuse construction materials.听
The programme also contains a not-very-veiled threat that the Ministry of Housing, Communities & Local Government will encourage local authorities to use the planning system to promote a preference for reuse and refurbishment of existing buildings and set targets for the amount of carbon emitted in the manufacture of materials used in new developments.
However as Defra admits, reusable components do not have much market value at present: 鈥淟ow rates of reuse can also be attributed to the high volume, low value nature of most construction materials, which means that reused materials are not price competitive, as well as a lack of information on materials that are available for reuse, and unreliable markets for secondary material.鈥�
Defra proposes that buildings should be designed to be disassembled rather than demolished and that the industry and government should oversee 鈥渁 shift in the design of construction products to encourage greater reuse and use of recycled materials鈥�.听
Examples include windows designed to be dismantled and precast concrete panels听
designed for reuse and 鈥渆ncouraging a shift towards recyclable materials and those with high recycled content鈥�.
And here comes the kicker. If these efforts at encouragement do not work, the government will consult on bringing at least some construction and demolition materials within the extended producer responsibility (EPR) regime by the end of 2025.
听EPR is an idea borrowed from the electrical and electronic goods industry and which is soon to be extend to packaging. It essentially means that a producer becomes responsible for the safe and legal recycling or disposal of anything it puts on the market.
The producer has to arrange for unwanted materials to be collected and under the EPR system the cost of dealing with these also falls on the producer.
When EPR for plastic in construction was first floated by ministers in 2019, Robbie Staniforth, head of policy and innovation at Ecosurety 鈥� a compliance scheme for EPR for electrical goods, packaging and batteries 鈥� said measures to address construction鈥檚 estimated 50,000 tonnes of plastic packaging waste generated each year were laudable but diverted attention from the sector鈥檚 much larger waste management issues.听
Staniforth said that cement-based products with specific waste management issues were most likely to become liable for EPR.
He said an EPR regime should funnel money from product manufacturers to the waste management industry but also provide incentives to choose reusable or recyclable products.
鈥淭he prevalence of short-life buildings that are down-cycled into aggregate could be reduced if the government is bold enough to implement comprehensive producer responsibility,鈥� Staniforth said.
He wondered whether charges should apply to the manufacturer, supplier or builder and concluded that, 鈥渆mbedding the environmental cost at a stage where quantity surveyors, buyers and architects can see it seems sensible鈥�.
EPR fees could also be used to even-up prices between established building materials that have benefitted from years of development and economies of scale and newer 鈥榲irtuous鈥� materials that lack the scale to compete.
Howard Button, chief executive of the National Federation of Demolition Contractors, wonders if the government has thought through any connection between its policies on waste and demolition and those on encouraging prefabrication and off-site construction.
鈥淒isassembling buildings is probably a good idea but if you are going to do that someone has to want the materials at the end,鈥� he says.
鈥淒emolition contractors will sell anything they can but if there is no value in it they can鈥檛. Defra don鈥檛 seem to get that. They seem to think that everything has a value, but it doesn鈥檛.鈥�
Button says trouble will really come when in the fullness of time prefabricated building have to be demolished.
鈥淵ou can recycle stuff from old buildings, but what about the composites now used, or polystyrene which if used with a screen adheres to concrete. That will be a big issue in future,鈥� he says.
鈥淲hen you come to demolish a building you have no idea what is in there and it would help if they brought back site management waste plans 鈥� which were there once but seemed to have been dropped 鈥� or pre-demolition audits.鈥�
In the long term a demolition contractor might be less needed but there would be more demand for disassembly engineers, 鈥渁nd the industry will adapt to that鈥�, Button says.
Brian Berry, chief executive of the Federation of Master Builders, says the United Nations Climate Change conference later this year is bound to focus on decarbonisation in the built environment among its themes and Defra鈥檚 consultation forms part of that.
Berry calls for 鈥渁 national retrofit strategy that shows UK leadership on the challenge of reducing energy demand in existing homes鈥�.听
He notes though that the majority of a building鈥檚 whole life carbon emissions come from the production of the materials used, which means the industry 鈥渕ust work with government to find sustainable solutions to this issue鈥�.听
Berry adds: 鈥淎ny policies to drive change should have local builders at their heart, who form 99% of the construction industry. The benefits of reducing waste for local builders include healthier margins that unlock more resource to invest back into training.鈥�
Other industries from electronics to textiles are being forced to rethink how they use and dispose of materials as policymakers strive for zero-carbon measures. It looks like construction鈥檚 turn is coming.
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