September 27, 2021

Closing the loop: Why the construction industry must embrace the circular economy to become truly sustainable

Stephen Hemmings, head of environment and sustainability at drywall construction materials manufacturer, Siniat, outlines why the construction sector needs to look beyond simply new homes’ performance and instead, towards the circular economy in order to become truly sustainable.


In January, the government published its response to the Future Homes Standard, confirming that all new homes should meet net zero by 2025. As part of this, new homes will be required to be highly energy efficient, with low carbon heating.

While new homes’ performance is a crucial factor in the journey towards net zero, the construction industry must look far beyond this and put in place more ambitious, and wider, sustainability strategies. Only by doing this can it become truly sustainable. One of the best ways we can achieve this is through embracing the circular economy. It’s essential that the industry not only considers changes in the way it designs and builds new developments, but also what happens to building materials at the end of their life.

Beginning at the end

While this might not be the most natural thought process for developers – with their main focus tending to centre on delivering the best product for customers – considering what happens when a building is no longer fit for purpose, at the beginning of its journey, is crucial.

From the outset, building designers and developers should be planning for the deconstruction of a building at the end of its life, rather than demolition. This process begins at the design and specification stage, where materials should be selected for their ability to be recycled, rather than simply on product performance.

We took this learning from our involvement in Gypsum to Gypsum – an EU Commissioned research project set up to explore how to move to a closed-loop model of material use. The same study identified that closed-loop recycling reduces the whole life carbon of projects, compared to traditional approaches – important findings when you consider that whole life carbon assessment is becoming a key consideration for developers. While this study looked at gypsum – the main component in plasterboard – its suggestions can be applied more widely. In fact, the closed loop model is already being used across different areas of the construction sector, particularly around plastics.

Change through collaboration

Of course, using recyclable materials alone doesn’t equal progress. Certain building materials are, in principle, infinitely recyclable, yet a huge percentage still aren’t collected for recycling at the end of their life. So, this change of approach requires the entire supply chain – from manufacturers and recyclers, to specifiers and architects, to contractors and installers – to get on board and adopt a circular model of material use. This isn’t always easy and requires a lot of education, training, and continued collaboration.

For manufacturers like us, closed-loop recycling is more or less cost neutral but we are driven to pursue it to achieve circular economy advantages. It also ensures we’re not reliant on large quantities of virgin material. As a result, this is something we have prioritised over the past few years and now our plasterboard has post-consumer recycled content of over 20% as standard – around twice the sector average. We expect this figure to rise to 30% by 2025. This hasn’t been an easy journey though and has required substantial investment over a number of years.

For others, such as onsite workers, the motivations for adopting the circular model might not be as immediately apparent. However, the importance of cross supply chain collaboration is obvious when you consider one of the core challenges of recycling gypsum. Contamination with other materials poses a huge problem, disruptive to productivity, so the cleanest possible sources from well-segregated gypsum collections are preferred. Unfortunately, this is not always happening in practice. It sounds simple, but it’s quite common for products like empty sealant packages to be thrown into plasterboard skips onsite, which then slows recyclers down when having to separate this. Here, training and awareness are needed at site level to ensure that nothing other than plasterboard goes in the plasterboard skip, for example.

Having the right infrastructure in place is also key. At Siniat, we’ve invested in our own waste recovery business to ensure a consistent supply of post-consumer gypsum is returned from sites back into our manufacturing process.   Our manufacturing plants have been upgraded to facilitate this and we’ve just had the green light on planning permission for a new advanced facility in Bristol, specially designed for using high quantities of recycled material.

Closing the loop

While adopting a circular model in the construction sector won’t be an overnight job, it’s vital. Ultimately, if we can get the whole industry working together, on both a macro and micro scale, change will start to happen. They say slowly but surely wins the race, but with huge targets in place for the sector over the next decade, we don’t have time to sit back and simply wait – action needs taking now. For architects and developers in particular, taking a holistic view of a building’s lifecycle, from design through to deconstruction, is an important place to start.