Reusability by Design
by Michael Cockram
The U.S. waste stream from demolition and construction amounts to about 150 million tons (136 million metric tons) annually. About 92 percent of this waste goes into landfills. In other industrialized nations, architects, the building sector, and regulators are doing more than in the United States to create a culture of building construction that reduces the future waste stream.
One strategy for such a reduction is to create buildings with components that are accessible to future recovery. In typical U.S. construction, too much material is trapped within building systems, making downstream disassembly impractical.
Germany has made significant strides in waste recovery in disassembling buildings. Working with a building environment in which 75 percent of structures are masonry, the Germans have a recovery rate in excess of 95 percent for many structures. They are also emphasizing the use of new technologies incorporating specialized machines to assist in dismantling buildings. These machines could cut in half the time needed to dismantle a building. This would be a critical advance because one of the main economic disadvantages of disassembly is that it tends to take much longer than simple demolition.
Germany also leads the way in requiring "extended producer responsibility" in manufacturing. Industrial producers are made responsible for the eventual disassembly and recovery of materials from the products they produce. This has inspired innovations in car design and construction, some of which could transfer into building construction practice.
Key features of this approach include: 1) identifying materials (especially plastics) so their composition is evident, 2) using fewer fasteners and using fasteners that are easily disassembled, 3) selecting reusable or recyclable materials, 4) reducing the number of types of materials, and 5) eliminating toxic materials as much as possible. >>>
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Components such as fixtures and windows are easily reused while adhesives and fasteners send aluminum siding to the scrap yard.
Photo: Michael Cockram
Older buildings often yield good quality materials, but the use of small pieces rather than sheet materials makes deconstruction labor intensive.
Photo: Michael Cockram
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