44 14 Create Building- Component Exchanges What if building components were sold and resold and resold again? To reuse building materials, they need to be recovered, inspected, stored, and resold. Institutions that make this exchange, verification, and revaluing possible could be exciting new actors in the material supply chain. Building-component exchange companies survey buildings that are to be demolished or renovated and assess the feasibility of reclaiming components; act as experts in carefully extracting and transporting the materials; sort, clean, and store the components; and build a client pool of contractors and designers to whom they can resell. Their role as guarantors for the resold components is equally important. Without a legal entity that can be held liable in the event of failure, building components—especially structural assemblies that need to be retested—often cannot be reused. Specifications also play an important role in facilitating or hindering reuse. They could be assessed and potentially rewritten to enable the use of reclaimed materials wherever possible by, for example, allowing for irregular lengths. 1 1 Maarten Gielen, lecture at ETH Zurich, April 1, 2015.