Wednesday, June 6, 2012
Skyscrapers of Wood
Years ago I worked in new construction. I didn't do it for long; it was hard work, and, as a plumbing apprentice, the pay was low. But it gave me an appreciation for construction techniques. (It also gave me sore knees and bruises on my shoulders from carrying around 22 foot lenghts of pipe.)
Even after I was out of construction, I remained interested in new innovations.
So I was astonished to read in yesterday's New York Times about Cross-Laminated Timber, or CLT, which is so strong that it forms the basis for a nine-story residential tower in London. A wooden skyscraper!
Widely used in Europe, CLT consists of panels of multiple layers, up to 6 inches thick. Within each panel, layers of wood boards are glued together. The grain of the wood in each layer is perpendicular to the adjacent layer, giving the panels tremendous strength. The result is a substance strong enough to replace steel, yet made from sustainable resources!
Trees, of course, absorb carbon dioxide, so CRT has a low carbon footprint. And the panels (which look rather like giant, thick plywood) are made to size and cut in advance. This makes construction faster. As with any pre-fabricated building, the panels are simply bolted together.
The article even claims that CRT panels are slow to burn: as the outer layer becomes charred, it protects the inner core from heating.
The use of CRT panels is just beginning in the United States. So far I haven't heard any negatives about the use of CRT. I'd be interested in seeing a building constructed with this technology.
Manufacturing CRT in the USA might also solve an environmental problem: we have millions of dead pine trees, killed by beetles, still standing and posing a fire threat. Recycling some already-dead trees into CRT could be part of the solution.
Has anyone heard an negatives about CRT technology?