How do we design out waste in the circular economy?
Charlie Law
Construction waste is often assumed to be the result of the building contractor’s inefficiencies, but much of the waste that is produced is actually as a result of the design. More than 80 million tonnes of waste is estimated to have been produced by the construction industry in 2011, therefore to achieve a circular economy with zero waste it is essential that the building, the individual elements within it and the packaging these components arrive in are well designed.
WRAP (the Waste and Resources Action Programme) has produced a lot of information on Designing for Resource Efficiency which is specifically aimed at architects and other members of the design team, but they could also easily be adopted by materials manufacturers to improve their products and packaging. The guides cover five key areas:
Design for re-use and recovery
Make the best use of the existing resources on the site. If there are existing buildings on the site, can these be refurbished, or elements of the structures reused? Can certain elements be salvaged such as the bricks, or at the very least recycled into aggregate for use on the site? Can the excavated material be reused elsewhere on the site, such as in landscaping? For packaging, could we design for reuse and return, rather than disposal?
Design for off-site construction
Prefabrication is a great way to reduce construction waste on site. Steel frames are already a good example for this, but more could be done to encourage prefabrication of concrete and timber structures. Highly serviced areas could also all be prefabricated (such as WCs, kitchens, etc.) and new façade systems could be made to measure and created to go up more efficiently to avoid waste.
Design for materials optimisation
Make the most efficient use of resources. Design door and window openings to tie in with the façade dimensions (e.g. brickwork) so minimal cutting is required. This can also mean designing for optimum service life.
Design for waste efficient procurement
Design the building so it can be built as efficiently as possible. Think about the formwork required for in-situ concrete structures (20% of BAM construction waste is timber, much of which comes from formwork). Post tensioned structures with flat slabs reduce formwork waste and aid services installation.
Design for flexibility and deconstruction
This ensures whole life waste is reduced. An example is by using relocatable partitions where there is a probability that spaces will be reconfigured. Designing for deconstruction also allows for the materials to be easily reused at the end of the building’s life. For example laying bricks in lime mortar means they could be dismantled more easily.
BAM would add one more to these.......
Finalise design before construction
Late changes in design may require rework of already constructed areas and reduce the scope for off-site construction.
Thinking ahead will ensure a lean, less wasteful construction process, with minimal environmental impact and lower production costs. By encouraging not only designers, but also manufacturers, suppliers and contractors to design and plan for resource efficiency, we are moving closer towards a circular economy and more sustainable buildings.
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