In our first Thought Leadership article on the World Green Building Council (WorldGBC) global #CircularityAccelerator programme, WSP share their knowledge and reflections on the circular built environment.
It is easy to feel like you’re going round in circles when talking about a circular built environment. Isn’t it somehow contradictory to design buildings for the longest life possible, while also ensuring that they can be disassembled when they become obsolete? Or to propose that the future lies with modular systems, when the past tells us that long-span structures tend to be easier to adapt and reuse? Or to call for “loose fit” buildings when they usually need more structural materials, increasing their embodied carbon?
Yet it’s not surprising that there are different approaches. The sheer variety of our built environment suggests that we have never created the perfect building. By extension, there is unlikely to be a magic formula for ensuring that buildings and their components stay in use for as long as possible. When WSP’s thought leadership magazine, The Possible, set out to define “the ultimate flexible building”, it concluded that there could be no such thing.
It is useful to look at this through the lens of heritage buildings. On one level, they are the great survivors, and can offer clues as to why some buildings endure while others perish. Large, column-free structures such as Victorian warehouses have proved almost endlessly adaptable. Likewise, buildings made from robust, easy-to-maintain materials like stone and concrete have an in-built advantage. Character is a more nebulous architectural quality, but perhaps the most important. “If people don’t find a building useful and comfortable, and a delight, then they won’t make the effort to adapt and maintain it,” points out WSP heritage expert Nick Corbett.
Advances in analysis and modelling are bringing a more science-based approach to heritage work and also opening up new possibilities. At the flagship Centre Block rehabilitation at the Canadian parliament in Ottawa, for example, WSP’s research showed that heritage masonry walls could be insulated without increasing the risk of condensation, mould or freeze-thaw damage, challenging received wisdom. “This is not a sweeping conclusion [but] it does show that, by basing decisions on analysis rather than gut instinct, we can come up with better, more sustainable and enduring solutions,” says Martin Sing, team lead for sustainability and energy. Put simply, the more we are able to analyse, the less we may need to build.
Emerging technologies also have implications for how we design longevity into new buildings. Modular systems were once dismissed as inflexible, but projects such as InnoCell, a 17-storey residential and co-working tower at Hong Kong Science Park, show how digital tools can enable plug-in modules to be swapped out, reconfigured or reused at a different location. “Each steel module is simply bolted to its neighbours,” explains Richard Chan-Hang Lee, WSP managing director of building structures in the China region. “If completely different modules were one day needed, then the existing ones could be removed from around the core, layer by layer.”
This acknowledges another fundamental lesson from the past: sometimes buildings do cease to perform a useful function. To design one without considering how it could be dismantled is to ignore the fact that the future rarely unfolds in the way we expect. This has become a particularly urgent problem in the rapidly expanding engineered timber sector. Some estimates put the volume of recycled wood products as low as 30%, with most timber structures either burnt or sent to landfill at the end of their life, releasing the carbon they have sequestered back into the atmosphere. “The way that most timber buildings are currently designed, with no thought for how the components might be recovered and reused, makes this a certainty,” says Thomas Musson, a structural engineer and consultant with WSP in the Netherlands. The solution, he adds, will combine traditional knowhow and pragmatic forethought with digital twins, QR codes and cloud databases.
In short, circularity requires us to learn from the past, use all available tools in the present, and try to predict an uncertain future. In this, at least, the built environment never changes.
