Nearly a quarter of the United States’ waste stream is attributed to construction and demolition. For an interview for REVOVLE, Daniel Overbey shares how circular economy is already transforming the built environment.
The urgency to adopt circular strategies has never been greater. And as we move towards LEED v5, the upcoming iteration of the widely recognized green building rating system, Daniel Overbey, Director of Sustainability at Browning Day, LEED (Leadership in Energy and Environmental Design) Fellow, sheds light on this pivotal shift.
LEED building certification is a globally recognized green building program developed by the U.S. Green Building Council (USGBC). It provides a framework for evaluating the environmental performance of buildings and encourages sustainable design practices across various types of construction projects. It is awarded based on a point system, where buildings earn credits for meeting specific prerequisites in categories such as energy efficiency, water conservation, materials sourcing, and indoor environmental quality.
In this conversation, Overbey details the importance of minimizing waste, reusing materials, and leveraging third-party validated programs to ensure circularity in construction throughout the whole lifecycle of buildings.
First question: How would you define the circular economy in the context of the built environment, and what are some key principles that can drive its implementation?
As it relates to the building sector, the circular economy can be realized through the pursuit of strategies that minimize waste through the construction process, reduce the need for new materials, and seek to maximize opportunities where existing building materials, components, and resources are reused, repaired, and recycled. For new building products and materials, we must leverage rigorous third-party validated programs that better ensure circularity in construction with regard to manufacture, transport, installation, and end-of-life outcomes.
Philosophically, the tenets of circular economy are embedded in the ideology defined by William McDonough and Michael Braungart in their 2002 book, Cradle to Cradle: Remaking the Way We Make Things. That book had a profound influence on my perspective on building design and construction.
For new building products and materials, we must leverage rigorous third-party validated programs that better ensure circularity in construction with regard to manufacture, transport, installation, and end-of-life outcomes.
The notion that design is the first signal of human intention; that the concept of waste is human-made because in nature waste for one system will be food for another system; that everything we make should be reconstituted into either a natural or technical metabolism.
We did not call it ‘circularity’ back then, but this book established the foundation for many sustainability principles that have developed today – including regenerative design and circular economy.
What are the main barriers or challenges hindering the adoption of circular economy practices in the built environment, and how can they be overcome?
Nobody is going to argue with the notion that the built environment should move toward deeper circularity. Construction and demolition waste (CDW) constitutes nearly a quarter of the United States’ waste stream. The US Environmental Protection Agency put this number at around 600 million tons.
Globally, the percentage is even higher as around a third of all solid waste is from construction. However, some countries are setting ambitious goals and demonstrating that deep reductions in CDW are possible.
Nobody is going to argue with the notion that the built environment should move toward deeper circularity.
CDW constitutes the largest solid waste stream in the European Union (EU). This was identified and clarified, then the EU set a goal to reduce CDW by 70% by the year 2020.
Regulation, management protocols, and guidelines followed. The result: many countries in the EU have exceeded this 70% target, achieving a nearly 90% reduction. The initiatives and programs vary, though at their core, they harmonize around reuse, recycling, and material recovery. This constitutes great success, but it was driven by a regulatory framework.
What is the greatest barrier to achieving deeper circularity on building projects? Time and time again, success in realizing sustainability objectives on building projects boils down to financial resources. Our economies are strained, budgets for our capital projects are extremely tight, and many of our countries are struggling with inflation. Every building project is confronted with budgetary challenges. As a result, the gravity will fall to the regulatory ‘floor.’
The EU raised the floor thoughtfully, and now we see the ingenuity of the market figuring it out. This is our classic ‘carrot and stick’ dynamic. Infuse financial incentives into the market to make the pursuit of the construction industry’s circularity best practices more economically variable than the ‘business as usual’ approach, then the market will transition faster.
What are some financial incentives that encourage circular economy practices in the built environment?
There are many examples of green financing programs. Again, I could point to Europe as a leading example where, for instance, the European Investment Bank has raised over €10 billion in green bonds and is now the world’s largest issuer. The World Bank is another example.
Tax incentives have proven to be very effective. In the US, a transition to the circular economy was a driver for the recent Inflation Reduction Act and Bipartisan Infrastructure Law – through which $48 billion was allocated to the building sector, specifically.
Do you see any emerging business models that can advance the circular economy?
In terms of business models, I see the McDonough and Braungart notion of ‘products-as-a-service’ starting to take hold in the building sector. Renting or leasing has been common in the automotive industry and housing sector for a long time. We see the products-as-a-service model with technology and e-waste because it allows manufacturers to salvage key elements. We trade in our smartphones for a discount toward the price of a new smartphone.
What could such a model mean in the building construction industry? Some product manufacturers are already implementing reclamation and recycling programs. Interface is doing this with carpet. Armstrong has a well-established ceiling tile recycling program. Many others are doing likewise.
We see the products-as-a-service model with technology and e-waste because it allows manufacturers to salvage key elements.
The New York City Economic Development Corporation recently found that masonry comprised 35% of the city’s CDW – more than wood, metals, roofing, and drywall combined. Can we commoditize and reconstitute masonry? This ‘waste’ could potentially become ‘food’ in a technical metabolism. But the economics must work for there to be wide-sale uptake.
In addition to regulatory context and financial frameworks, we have green building rating systems. Products like the LEED rating system offer stakeholders an ‘easy button’ to pursue sustainability without too many blind spots. Historically, LEED certification has left something to be desired regarding circular buildings. As a LEED Fellow, what are your thoughts on the impending changes coming with LEED version 5 and circularity?
Internationally, about a billion square feet of building space become LEED-certified every three years. LEED building certification has transformed the market in ways that are easy to take for granted.
For instance, Environmental Product Declarations have been around in some form since the 1980s, but they did not become commonplace until LEED started utilizing them about a decade ago. The Forest Stewardship Council was founded in the early 1990s, but their chain-of-custody protocol was not widely utilized until LEED incorporated it. There will always be critics but show me something more transformative to the global building sector than LEED certification and BREEAM.
LEED v5 will continue to incentivize building reuse and this matters a lot for circularity and the reduction of embodied carbon.
LEED v5 will continue to incentivize building reuse and this matters a lot for circularity and the reduction of embodied carbon. For new construction projects, the Optimize Building Products “super credit” (for example, pulls a lot of things together under a single credit and offers up to five points) in the BD+C version of the upcoming LEED v5 rating system will likely leverage existing single- and multi-attribute building product certifications such that teams can easily advance circularity throughout the technical specifications of building projects.
By specifying, say, GreenCircle Closed-Loop certification, Cradle to Cradle Gold certification, or products that come from TRUE Zero Waste manufacturers, teams can systematically ensure that an increasing proportion of a building’s products and materials are procured through leaders in the industry who have gone through third-party verification that their offerings are the real deal. If this sounds simple, that’s intentional. The market likes simplicity. We need the path of circular buildings to be simplified.
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