Circular economy is a term that has been applied to construction over several years. It is only now, with a greater awareness of the need to reduce our carbon footprint, that the principles of the circular economy are passing from research projects into commercial applications.
Several new organisations have emerged that are championing circular economy principles, and these are mentioned in the references below. Our intention is not to repeat those ideas here but rather give the project manager’s perspective and understanding on the challenges and opportunities that the circular economy brings to construction. Each of the following areas are highlighted by the UKGBC as being central to the achievement of a circular economy.
Designing out waste
Construction is a hugely wasteful activity. Be it demolition waste, new materials that do not fit, packaging, installations that are not of the correct quality or human error, all contribute to construction waste. While site operations of main and sub-contractors have become better organised, there is still room for improvement.
As climate change awareness and Net Zero gain momentum, there is a growing expectation that the carbon case to demolish an existing asset is fully understood before anew buildings is commissioned.
The lowest footprint building is the one that uses existing materials or creates a new building from materials that have already been used.
Designing for resource efficiency
There is a limit to the resources that we should use in the creation of buildings. Hence, our focus must be on making the most of those resources as efficiently as possible. This applies to the materials used in the construction of the building and of the energy used to keep the building habitable.
Many of the most significant improvements can only be achieved at RIBA stage 0 to RIBA Stage 2. After these stages, the building is taking shape and decisions to avoid new building or upcycle existing materials will be missed.
Designing for deconstruction and disassembly
Should a new build be the only sustainable solution, the design needs to recognise that it will one day be decommissioned, and the components hopefully incorporated in a subsequent building. This has a major impact on the choice of materials and the way that they are joined to each other. A simple example of which could see a steel framed building unbolted, and the steel either reused in its original form or melted down into new products in the future. Concrete, on the other hand, may be crushed at the end of its life but is not easily combined into new products.
Using more renewable energy
Renewable energy now accounts for a much larger part of the UK’s energy supply. Existing buildings that utilise fossil fuels as their primary energy source will need to move to renewable energy sources.
Reducing embodied carbon over a whole building lifecycle
Different elements of a building are going to need to be replaced at different points. For instance, cladding features may be designed with a lifespan of 25 years, whereas services may fail after 20 years of continuous use. Hence, the planning of realistic strategies for replacing key elements is becoming all the more critical. Similarly, the need to hold information about a building in a more transparent manner will change the way in which Operating and Maintenance information is stored and updated. There is now talk of passports being developed for building components. How and where these are stored is a challenge.