Cross Laminated Timber is Ready for Prime Time

CLT showroomLloyd Alter/CC BY 2.0

Thousands of houses were destroyed in the 2009 Italian earthquake. Instead of rebuilding the houses in block, over 4000 have been built in cross laminated timber, or CLT. It is a favorite material of mine; it is made of wood, which sequesters carbon dioxide for the life of the building; it is incredibly strong; we have shown buildings like Waugh Thistleton's timber tower that is nine storeys high. It replaces concrete, which is responsible for as much as 5% of the world's CO2 and the excavation of mountains worth of aggregate. It is fast flatpack design and construction; the timber tower was built by four workmen in a month. This three storey showroom at the XTLEXPO in Milan was assembled by two men in ten hours.

Not only that, but in North America the Mountain pine beetle is ravaging the forests, and if the wood is not cut it will rot, releasing all of its captured CO2. CLT provides a use for that wood. If new construction used it instead of concrete or steel, or even traditional wood stud, we could go a long way to using this stuff before it is worthless.

Finger jointsLloyd Alter/CC BY 2.0

I always thought that the technology came from Austria, but northern Italy is a hotbed of CLT. The Italians produce the equipment needed to make the stuff and The Timber Machinery Alliance will sell you a complete turnkey package starting at about 2 million euros. The consortium of manufacturers provide a finger jointer that makes long pieces of wood out of what you or I would use as kindling. Then a robot pushes it all together and move it to a press that cranks that applies tonnes of pressure and turns it into a panel. It then moves to a CNC router that carves out the window openings and lays in grooves for electrical wiring and plumbing as if you were printing a circuit board. Finally a sander gives it a furniture-like finish.

finger jointerFinger jointer/ Lloyd Alter/CC BY 2.0

Perhaps I am overwhelmed by the shock of the new here, but I can't help thinking that this is the ultimate prefab product. It is not the usual old material assembled in a factory instead of on site, but an entirely new way of building, using a new material that is perfectly adapted to computer controlled design and construction. It is cheap to ship and easy to assemble. I wish I had 2 million euros, because this is the future of building in North America, and in such undersupply; after all there are five factories just in northern Italy, and as far as I know, only two in Canada and one in the United States. That's too little and given the mountain pine beetle situation, way too late.

CLT pressLloyd Alter/CC BY 2.0

Tags: Green Building | Italy


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