The need for a circularity measurement framework

The construction industry is at a turning point. The linear economic model of ‘take-make-use-dispose’ is unsustainable and carbon intensive; it’s one of the main reasons why our industry is currently responsible for over 50% of global material waste. 

Moving from a linear to a circular way of thinking in construction will require a change in how we approach projects. The reuse and recycling of materials must be prioritised from the start of a project if we want to reach net zero. 

Recently we have made significant strides in our ability to reclaim and reuse material as an industry, driven in part by a rise in closed-loop schemes and technology, such as material passports, which have enabled more circular treatment. However, at present, there is no industry defined metric for a 100% circular building.

Supporting policies and regulatory frameworks have a pivotal role in driving circular construction practices. Luisa Ramos Steiner, Senior Sustainability Manager shares her thoughts on how Governments and bodies must create a uniform standard for circularity, that incentivises adoption of circular approaches.

Key principles for measurement

In order to define industry-wide targets for circularity, we’re first going to have to agree on the principles and factors that make it up. The UK Green Building Council’s (UKGBC) article, ‘What Does it Mean to be 100% Circular?’, provides a strong starting point for this discussion, identifying potential metrics for the polar extremes of a 0% circular building and a 100% circular building, including:

• Material waste and retention
• Adaptability and disassembly
• Materials passporting
• Building in layers
• Demolition vs. deconstruction 
• Dematerialisation

These measures provide a useful checklist to consider when aiming for a circular project. This is not entirely straightforward since prioritising certain areas of circularity may come at the expense of others. For example, a commitment to retaining an existing structure may limit the potential for adaptable design. 

We attempted to build upon the discussion with our recent report, Closing Material Loops, developed in partnership with Arup. We took the criteria outlined by UKGBC and attempted to create a Red, Amber, Green (RAG) scorecard, giving a weighted rating for each one. This type of scorecard could play a foundational role in solidifying an industry standard for a circular economy. 

Have circularity in your sights from the start 

With circularity forming such an important part of the route to Net Zero, it should be a key metric for the success of a project from the outset, in the same way that carbon and green building certifications are currently. If you can fully commit to reuse from inception, you can maximise the carbon savings and resource efficiency across a project’s lifecycle. That said, it is never too late to implement circular practices. 

There are multiple (often legacy) projects which we began without specific consideration for circularity, but later, through collaboration with our clients, we explored options to trial materials passports. These allowed us to catalogue and track individual building components, capturing invaluable data and supporting the project being part of a circular construction economy. Best practice for circularity will require projects to pursue accredited circularity requirements at the design stage. 

Putting a number on it 

Defining and weighing up the factors that contribute to a circular building is challenging, which is why a quantitative legislative approach has not yet been formalised. However, we’re seeing public and private organisation make a start. For example, the London Plan’s Circular Economy Statement was a huge step forward in mandating requirements to build in a less linear way. The positive intention behind policies like this is vital to improving broad adoption of circularity. The next step to ensure that material reuse meets the scale required to reach broader net zero ambitions is to attach empirical targets that allow the industry to build clear roadmaps to adoption.