Could sustainably-grown wood formed into panels replace steel as the structural material of choice for taller buildings? The manufacturers of cross-laminated timber, or CLT for short, aim to find out.
Resembling sheets of very large plywood, CLT is an engineered product that is built from planks of wood about an inch thick. They are laid perpendicular to each other side to side, with grains crossing on each layer, and glued together to form panels which can then be cut to any size necessary. The new panels are strong enough to replace the steel typically used as a structural element in building construction, only requiring a small amount of the metal in the form of brackets and other hardware.
Pete McCrone from Innovative Timber Systems in Montana thinks CLT is the way to go. “This is the way we ought to be building,” he said to The New York Times. McCrone’s company wants to be first timber company to manufacture the product in the United States.
In the United Kingdom, a nine-story apartment building in London is constructed entirely of CLT from the second story up, making it one of the tallest wooden residential buildings in the entire world. Because CLT has been in use in Europe for long enough, builders understand the technology and concerns about structural integrity and fire protection have been addressed. Here in the U.S., builders are a little more hesitant to embrace the materials. “In a very short space of time they get it, because it’s simple — it’s large panels held together with large screws,” said McCrone.
However, CLTs do use a lot of wood. In fact, a single wall made from CLT can use six times as much wood to construct as a conventionally-framed wall. But that’s not necessarily a bad thing, because not only is wood a renewable resource but it is also nowhere near as harmful to the environment as mining the iron ore for steel can be.
The mining of iron ore to make steel can lead to all kinds of environmental damage, including deforestation, mountaintop removal, surface and groundwater destruction, and wildlife habitat interruptions. Mining can leave behind a trail of desolate land void of life or the ability to rehabilitate itself as well as contaminate water sources for animals and people alike. Sustainably growing, managing, and harvesting wood from trees can be done in a responsible and environmentally-friendly way.
As a resident of California, my immediate thoughts run to CLTs ability to withstand earthquakes. Can the technology survive the shaking of a west coast earthquake without falling over onto the neighboring building? Most apartment buildings here, while built fifty to sixty years ago, have been able to deal with the ground moving beneath them on a regular basis. If CLTs can do that and be more eco-friendly than the mining of iron ore, then I am all for it. Bring on my wooden apartment building!
Watch a video about Cross-Laminated Timber technology:
[via The New York Times]
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