When a Building Comes Down, Where Do Its Materials Go?

To understand buildings, consider cities. They are evolving, iterative systems whose peripheries and hinterlands are implicated in their growth, demanding material flows of natural resources and the expenditure of energy. So too with buildings, although such thinking is relatively new. And, as urban development marches on, it is as important to analyze the embodied energy and material output of buildings when they come down as when they go up. Such flows are sometimes redirected into recycled products, but more often they terminate in landfills, waterways, or worse.

As the environmental crisis worsens, we must ask: Can we reduce our demand on new resources? Need our built environment be in perpetual flux, an endless succession of destruction and rebuilding? For Kiel Moe, professor of architecture at McGill University, the discourse surrounding demolition and recycling is “fundamental to an ethos of planned obsolescence” and isn’t “a viable way to think about sustainable construction.” Resisting this “cycle of buildings” assigns greater importance to the architectural imagination— something that should excite designers. Creative reuse, retrofitting, and, most importantly, designing programmatically versatile buildings that last should be architects’ main objectives.

But the demolition-construction cycle also entails pragmatic challenges, which may offer important—albeit fundamentally incremental—solutions to our waste predicament. Design for disassembly should become part of architectural practice, and planning to systematically sort materials during demolition can make it easier to repurpose them. The high environmental and logistical cost of removal, transportation, and processing of materials for recycling should also give pause to wrecking-ball zealots.

Ultimately, once building materials are untethered to a structure, they will find a new home, preferably in an up-, re-, or downcycled context.