Circle forward: A retrospective investigation of the successes and barriers to implementing circular economy

Circular economy is no longer a new idea for the built environment. Across the industry, there is growing recognition that we need to design and deliver buildings in a way that reduces waste, keeps materials in use for longer, and supports the transition to net zero. The bigger challenge is how we move from ambition to action, and what successful circularity actually looks like when it is tested on real projects.

This is the focus of Cundall’s Circle Forward campaign. Through a series of project reviews, industry roundtables and conversations with clients, consultants, contractors and supply chain representatives, we are exploring how circular economy principles are being applied in practice, where the recurring challenges sit, and what needs to happen next to make circularity a more consistent part of project delivery. The purpose of the campaign is also to share this knowledge and practical learning more widely across the UK, helping to build confidence, accelerate adoption and support the wider shift towards making circular economy principles the norm within the built environment.

We begin with a retrospective review of five completed UK projects that implemented circular economy principles, drawing on the conversations with project delivery teams to identify recurring success, barrier and lessons learned. By speaking with members of the design teams involved, we wanted to understand which measures made the biggest difference, what barriers shaped decision-making, and what lessons could help inform future projects. These findings are helping to shape the next stages of Circle Forward by grounding the campaign in practical project experience.

The conversations explored several recurring themes that are central to improving circular economy outcomes: 

• The circularity measures that were applied on the project
• The biggest circularity wins
• The greatest facilitators of these wins
• The biggest obstacles to delivering circular outcomes
• The impact of circular economy principles on the project's programme
• What could have been done to improve circular economy outcomes
• Likelihood of including circular economy principles in future projects 

Together, these reflections provide a practical starting point for the campaign: a clearer view of what is already working, where the industry continues to face barriers, and how future conversations can focus on the actions needed to turn circular economy principles into everyday project practice.

What we learnt from the project review

Across all five projects, circular economy principles were actively incorporated into project delivery, demonstrating that these approaches are moving beyond pilot initiatives and into mainstream practice. Each project incorporated measures such as design for disassembly, adaptability and flexibility, alongside the use of reclaimed, reused or lower-carbon materials. This suggests that these approaches are no longer seen as niche or experimental; they are becoming part of the wider conversation around good design and responsible delivery.

However, the review also showed that some circular economy strategies remain harder to deliver than others. Off-site reuse of existing materials was the least commonly adopted measure, featuring in three of the five projects despite being widely recognised as one of the highest-impact circular economy interventions. While material reuse is often one of the most impactful ways to reduce waste and embodied carbon, it can also be one of the most complex to coordinate. Lead times, storage, logistics and procurement route all influence whether reuse is practical. The lesson is clear: these opportunities need to be explored early, before key procurement decisions become fixed. 

What circularity measures were applied on this project?

Client mandate and organisational buy-in emerged as the most consistently cited enablers of successful circular economy implementation across the projects reviewed. These were consistently identified as key enablers of successful circular economy implementation. Client leadership matters because it sets the ambition, shapes the brief and influences the teams appointed to deliver the work. Where circularity is supported from the outset, project teams are better placed to make decisions that align with those ambitions. 

What helped make the wins possible?

What was the biggest obstacle to delivering circular economy outcomes?

When teams reflected on their biggest successes, reused, recycled and low-carbon materials came through strongly. This is not surprising. Material choices are tangible, measurable and often easier to point to as evidence of circular delivery. But it also raises an important question for the industry: why are these solutions not yet the default? If reused and lower-carbon materials are consistently seen as successful interventions, then the next challenge is to strengthen the systems, supply chains and confidence needed to make them easier to specify and deliver.

By contrast, measures such as design for disassembly, adaptability, flexibility and material passports were less often described as standout project wins, even where they had been applied. This may be because their benefits are not always immediate. Designing for future recovery, reuse or flexibility can create long-term value, but that value may only become visible decades later. It is a reminder that some of the most important circular economy decisions made today may not be fully appreciated until much later in a building’s life.

Encouragingly, all five project teams said they would be very likely to apply circular economy principles again on future developments. This is an important finding. It suggests that, despite the challenges, teams are seeing value in circular approaches and are gaining confidence in how they can be integrated into project delivery.

What is still getting in the way?

While the review highlighted plenty of positive momentum, it also reinforced that circular economy delivery is not always straightforward. Programme risk came through as one of the most common concerns. On paper, this might seem slightly contradictory, as the circular economy measures that were ultimately delivered often had little or no impact on project timelines. But the reason is important: in several cases, measures that were seen as too risky for programme were not taken forward at all.

This shows how perceived risk can shape circular economy outcomes before a project ever reaches delivery. If a material or approach is thought to create uncertainty around availability, procurement or lead-in times, it may be discounted early, even if it could have offered carbon, waste or resource efficiency benefits. Examples included higher recycled-content materials such as concrete, steel and aluminium, where concerns around procurement routes and supply chain readiness influenced decision-making.

That is why earlier engagement with contractors, suppliers and material marketplaces was such a consistent theme in the conversations. Many circular interventions depend on knowing what is available, when it can be sourced, how it can be tested, and whether it can be integrated into the project without creating avoidable cost or programme pressures. The earlier those conversations happen, the more opportunity there is to turn circular ideas into viable project decisions.

There was a recurring message: circular economy principles are gaining traction, but they need the right project conditions to succeed. Strong client leadership aligned project teams and early supply chain involvement can make the difference between circularity being treated as an aspiration and being embedded as part of delivery. As Circle Forward continues, these insights give us a practical basis for deeper conversations with the industry about how we remove barriers, manage perceived risks and make circular design easier to implement on future projects.