Five top tips for building a circular economy

With the built environment demanding nearly half of the worlds extracted materials and generating around a third of the world’s waste, there is an urgent need to apply circular economy principles if the worst impacts of the climate crisis are to be averted.

In his latest book, The Handbook to Building a Circular Economy, AECOM Sustainability Director David Cheshire explains how a transition to a more regenerative model is urgently needed to tackle the climate crisis, before it’s too late.

This transformation will require systemic changes, starting from the decision on whether to build in the first place, right through to the way that we engage with the supply chain and how we deal with the end of the (first) life of buildings, elements, components and materials.

New planning policies are now driving change. The new London Plan includes circular economy policies that prioritise retention and refurbishment over demolition, disposal and new build. The policies ask for design teams to undertake pre-refurbishment / pre-demolition audits and reclamation of materials that are being stripped out. It requires buildings to be designed for adaptability, flexibility, and disassembly, whilst considering the whole life impacts from the embodied carbon of construction, the operational impacts, and the end-of-life plan for the building.

The London Plan’s circular economy design policy uses a diagram (Figure 1) from my first book, Building Revolutions, that summarises the design principles that have to be implemented. All projects that are referable to the Greater London Authority now have to provide a Circular Economy Statement that demonstrates how the proposals integrate the design principles and respect the hierarchy of retention and refit over new build.

Here are top five tips for transitioning to a more circular built environment:

1. Refurbish over new build: repurposing and refurbishing existing buildings is going to become increasingly important. The operational carbon emissions of a new building are far lower now thanks to a far cleaner, greener electricity grid and efficient building design. This has made the embodied carbon impacts – the emissions associated with pouring concrete, forging steel and extruding aluminium – far more important. Refurbishing instead of building new will save over half the embodied carbon, when compared to a new building. In the future, we are likely to see developers actively looking for buildings that are ripe for refurbishment rather than re-development.
2. Pre-refurbishment / pre-demolition audits: a detailed review of all the building elements and materials in a building before it is refurbished or demolished is essential to reclaim as much as possible and avoid everything being crushed and shredded and treated as waste. The audits should identify what can be reclaimed for reuse either on or off site and identify potential new uses, destinations or brokers for each item. There are now brokers, such as GlobeChain, who have created a reuse marketplace that redistributes unneeded items to those that need them. It has over 10,000 members and has diverted over 6.1 million kilograms of resources from landfill, creating savings of over €4.4 million for charities.
3. Use reclaimed components: the concept of mining the urban environment for components and materials from existing buildings is gaining traction. There are already manufacturers who will take waste and turn it back into new products: RMF will collect tiles from demolition and construction sites, clean them up, test their integrity, rewarranty them, and sell them for substantially less than the equivalent new product.
4. Use biocomposites: some manufacturers are making biologically-derived products. Biomanufacturing company Biohm has created an insulation board that is grown from mycelium – the fungal threads of mushrooms and other fungi. The product performs better than many other insulation products and is naturally fire-retardant – a crucial requirement to meet new regulations. Amazingly, rather than emitting carbon in manufacture, it actually locks away carbon into the material, making it a carbon sink. Using more biocomposites will radically reduce the embodied carbon impacts of the built environment.
5. Design for the next life: to be truly circular, designers have to be thinking about the next life for the building, its elements and materials to abolish the concept of waste entirely. Therefore, buildings should be designed to be more adaptable to reduce the risks of obsolescence and should be designed for disassembly to allow components to be reclaimed for reuse in the future.

Applying circular economy principles to the built environment could radically reduce its carbon footprint, slash demand for new materials and turn waste into a resource. With the climate crisis looming, we have to move away from the disposable, linear economy to a longer-term solution.

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