I admit it: I’m an unabashed proponent of the use of wood as a building material. “Wood is good.” From an environmental standpoint, there’s a lot to like: wood is renewable, has a low carbon footprint, and markets for wood products provide an incentive to grow and maintain forests, a fact that’s not often considered in forestry debates. Research on the production, manufacture, and disposal of wood products – so-called life cycle analysis – suggests that compared to steel and concrete, wood-based construction requires a lot less energy and results in significantly lower CO2 emissions. Read an article about Forest Products Life Cycle Analysis here (see page 5).
So when I hear about the potential for developing multi-story apartment complexes and other tall buildings with wood, I get pretty excited. The reason for all this excitement is cross-laminated timber (CLT). CLT is an engineered wood product, basically a wooden panel made of boards that are placed cross-wise to each other, which increases strength and stability. Hence the moniker “plywood on steroids.” CLT was actually developed in the 1990s in Switzerland, but has recently gained traction in both Europe and North America with changes in building codes permitting wooden structures taller than 4 or 6 stories.
Potential advantages of CLT in high rise construction include lower costs, faster build times, and improved environmental performance, including much lower embedded carbon emissions compared to steel or concrete. Of interest to folks in the Pacific Northwest, the material is made from softwood structural lumber, and we do a good job of producing that. Naturally, the public will be very concerned about how these structures would do in a fire or an earthquake. Perhaps surprisingly, the answer may be: pretty darn well.
I don’t know if CLT is a blip on the radar or a long term trend, but it’s an interesting story.
Some links:
Michael Green’s TED talk: Why we should build wooden skyscrapers
Six story wood buildings a game changer
Why these stunning wood skyscrapers could dominate the skylines of the future