Dario Cottafava
2020
In this publication, we argue that calling a building circular is not enough. Designers and decision-makers need a way to test what the claim means. The built environment produces more than a quarter of EU waste, relies heavily on virgin resources and leaves large volumes of material difficult to recover at the end of a building’s life. Existing indicators often focus on material flows—virgin input, unrecoverable waste and product life—but those measures are necessary rather than sufficient.
A building is not simply a collection of kilograms. Materials of equal mass can carry very different embodied-energy and carbon impacts. And a component that looks recyclable on paper can still be difficult to recover because of its connections to the rest of the building. We set out to bridge that gap between environmental impact and design choice.
We combined the Material Circularity Indicator with embodied energy, embodied carbon-dioxide assessment and Design for Disassembly criteria. This produced two related tools: the Building Circularity Indicator (BCI) and Predictive BCI (PBCI), each available in full and simplified versions. At the macro level, they include energy and carbon rather than mass alone. At the meso level, they ask whether components can realistically enter reuse or recycling chains. At the micro level, they connect future recovery to decisions about materials, connections, access, flexibility and building layers.
We tested the approach on eight demonstrator projects across European climate zones. The cases showed major differences in embodied impact and in circularity scores depending on whether mass, energy, carbon and recoverability were considered. The simplified version was particularly useful when detailed data existed for only a few dozen components. But the tests also made clear that an indicator is only as reliable as its boundaries and assumptions; interpretations of disassembly criteria can significantly change a result.
Our contribution is a way to make circularity visible without losing future recovery or environmental impact. For scores to guide design rather than decorate it, practitioners need clear boundaries, a minimum set of assessed components and precise definitions of whether they are judging a material, a component or its relation to the building as a whole.