Rashmi Rungta, a PGD student at the Cambridge Institute of Sustainability Leadership, discusses the value of re-using waste in construction
When Britain declared a climate and ecological emergency in 2019, it signalled a national willingness to confront uncomfortable truths. Yet while announcing targets is easy, achieving them is not. Nowhere is this gap between ambition and practice more glaring than in construction, a sector that shapes the built environment even as it quietly fuels some of our greatest environmental and economic inefficiencies.
Construction consumes resources with an extraordinary appetite. Globally, the industry is responsible for roughly 40% of carbon emissions and waste. In the United Kingdom, construction and demolition refuse accounts for nearly two-thirds of the country’s total waste stream. The absurdity peaks with one statistic: more than 10% of building materials purchased in the UK never make it into a structure. They go straight to the landfill. At a time of housing shortages, strained budgets and mounting climate pressures, such wastefulness is more than an environmental concern; it is an economic failure.
And yet this is not an inevitable cost of development. It is the result of choices made long before the first digger arrives on site. This is why cities and local authorities, especially influential ones such as the Westminster City Council, hold the key. National governments may set high-level direction, but local authorities determine what gets built, how it is built and what happens to the materials left behind. If Britain is to achieve a circular, resource-efficient construction sector, reform must begin at the local level and be supported at the national level.
I know this because I have spent the past two decades working across technology, governance and transformation, and more recently through my postgraduate research at the Cambridge Institute for Sustainability Leadership (CISL). That work, alongside my participation in Westminster’s Citizens’ Climate Assembly in the record-breaking summer of 2023, exposed a simple truth: the UK cannot hope to reach circularity until it can consistently measure the waste produced on construction sites. Today, most cities cannot. They are trying to solve a materials crisis with almost no reliable data.
A personal lens on a public problem
The Westminster Climate Assembly provided an unusually candid snapshot of how communities, businesses, and policymakers grapple with the realities of climate change. Among all, the strongest recommendation was for the council to steer construction firms toward circular, low-waste practices. My professional experience and academic work highlighted the gap between what citizens demanded and what local authorities could deliver in a visible manner.
That gap is why I chose Westminster City Council as the subject of my research. It is a borough unlike any other: politically symbolic, densely built, architecturally significant and economically powerful. If any local authority can model what effective construction governance looks like, it should be the Westminster City Council. And yet, Westminster, like most local authorities, lacks the systems to consistently monitor its construction waste. Without measurement, circularity remains more slogan than strategy.
My connection to CISL has only sharpened that view. Following from my work with Westminster, I’m currently collaborating with CISL’s Living Lab for innovation in the built environment to develop a case study for my Diploma in Sustainability Leadership. This case study will showcase how the CISL Entopia Building integrated circularity into its development to achieve award-winning outcomes and what can be learnt from this project and the wider sectoral context to scale action.
Through the CISL Living Labs, my aim is to share CISL’s achievement in demonstrating circularity within a historical building, showcasing, in practice, how heritage, innovation and waste reduction can coexist. If the renovation of a century-old building can achieve nearly 44,000kg of material diverted from landfill, representing ~86,000kg of CO2e avoided, the wider industry has little excuse for not doing the same. But inspiration must be matched with governance, and governance begins with data.
Waste isn’t a by-product — it’s a system design failure
Construction waste is often explained away as an unfortunate but unavoidable by-product of materials breaking, designs changing, timelines slipping, and budgets tightening. Such reasoning is tidy but wrong. Waste begins not on a construction site but on the architect’s desk, in procurement protocols and in planning assumptions that hard-wire linearity into a project before ground is even broken.
The deeper problem is that most local authorities cannot confidently state what is leaving their sites. Waste reporting is patchy. Data is often self-reported and rarely interrogated. Even the sector’s favourite performance metric, the “recovery rate” (% of waste recycled compared to total waste generated), is optimistic to the point of distortion. Much of what qualifies as recovered material is merely crushed into low-grade fillers and used in roads or as backfill; this is downcycling, not circularity. Genuine reuse remains the exception.
The economic system compounds the problem. Developers respond rationally to incentives: the cheapest, quickest route is usually linear. Circular design remains unattractive because the system prioritises short-term savings over lifetime value. Cultural assumptions reinforce this inertia. Reused or repurposed materials are often viewed as risky or inferior; methodologies like design-for-disassembly remain relatively niche.
Funders or insurance firms are reluctant to endorse circular construction, viewing it as higher risk and thus leading to increased premiums or even uninsurability. While councils often set ambitious sustainability targets, they often lack the necessary monitoring infrastructure to enforce them. For example, the London Plan may require 95% reuse, recycling or recovery, but without measurement, enforcement is little more than hope.
The truth is unavoidable: construction waste is not the result of sloppy site management but of systemic, long-standing governance failure. Better bins will not fix it; better systems might.
Circular construction isn’t a burden, but a competitive advantage
The irony is that circular construction is not a financial sacrifice. It is a missed opportunity hiding in plain sight. Cities experimenting with circular models report that projects become more resilient, and exposure to volatile global supply chains shrinks. Treating waste as a resource, not debris, unlocks innovation.
Technologies once considered niche, such as material passports, modular assembly, design for disassembly, and bio-based materials, are rapidly becoming central to responsible construction. Developers who adopt these methods win credibility in a market increasingly shaped by ESG scrutiny and investor expectations. Workers benefit too. Roles in digital modelling, reverse logistics and materials recovery offer cleaner, safer and more resilient jobs than many traditional site roles.
Cities reap the wider benefits: cleaner air, fewer lorries, less noise, and the potential to reclaim land for biodiversity and public use. Circularity is not merely environmentally virtuous. It is economically rational and socially desirable.
So, what’s holding us back?
Not technology, not developer hostility, and not money; waste itself is costly. The real barriers are institutional and cultural.
Circularity is seldom mentioned in client briefs, supply chains are fragmented, and the industry struggles with persistent skills gaps. Councils lack standardised monitoring systems, leaving sustainability conditions unenforced. Responsibility for waste is diffused across so many actors that no one is truly accountable. The system, by design, allows waste to flourish unchecked.
Unless this governance architecture changes, waste will continue to win.
Why cities hold the levers of change
Local authorities are the key points of contact through which every construction project must pass. They approve planning applications, negotiate with developers and enforce the rules, if they choose to. Crucially, they shape local markets.
With consistent construction waste monitoring systems, councils could establish reliable baselines, set enforceable circularity targets and provide evidence-backed guidance to developers. Such systems would curb greenwashing, build public trust and help align planning departments, environmental teams and procurement processes. This would also begin to overcome other existing obstacles, setting and enforcing targets in other contexts has seen great levels of innovation to break down barriers and enable rapid change.
This is not a radical proposal. Councils already monitor noise, dust, traffic and hours of operation on building sites. Adding waste is a logical extension. The upfront investment is modest; the long-term savings are substantial.
Transforming construction waste management does not require dismantling existing institutions. It requires clarity, coordination and the discipline to apply rules consistently.
Progress towards a practical, governable path forward
In a major step forward, in November 2025, Westminster City Council updated its ‘Code of Construction’ to require developers to submit circular economy statements, pre-demolition audits, and site waste management plans in accordance with the London Plan 2021 before starting the construction. It also announced that it will now, for the first time, conduct site visits to audit compliance with these documents. Westminster residents and businesses have been invited to provide their views on these changes. I am pleased to have been part of this initiative and to have utilised my studies at CISL to provide evidence that enabled this development to occur.
Scaling impact
This is not the end; it is now imperative that Westminster’s leadership is translated across other Local Authorities and at a national level. Through my upcoming case study of the CISL Entopia Building’s circularity approach, I aim to further amplify this knowledge and leverage the Living Lab network to build confidence and provide evidence of the opportunities achievable through transformation.
The post Are we missing the economic value of construction waste? appeared first on Planning, Building & Construction Today.
