By: Lloyd Alter
Three years ago I wrote about Waugh Thistleton’s Timber Tower, what was to be the tallest wood residential building in the world. It’s up now, and Craig Liddell, commercial director for KLH UK, the builder, spoke at the Green Building Festival in Toronto. The building is a remarkable mix of design and wood technology, all completely invisible to the people inside.
The building is made from prefabricated cross-laminated timber (CLT) panels, made in Austria from sustainably harvested lumber. They are strong; Craig says they can go up to fifteen stories. They are fire resistant; unlike steel, it doesn’t lose its strength when it gets hot. In a fire, the char that forms on it is actually an insulator.
The panels are connected with angles, and proprietary connectors; here you can see a balcony detail, with waterproofing applied on site after the panels are connected. The amount of waste from the entire construction process could fit in a wastebasket.
I think it unfortunate that they covered up all of that warm wood; it was gorgeous and now the same view just shows ordinary drywall. But that was evidently the point, to show that a building made of wood was in the end, looked no different than conventional construction.
Except there is one big difference: the manufacture of concrete is a huge producer of carbon dioxide, aggregate mining scars our countryside and it takes four times as long to build. Wood is renewable and building with it sequesters carbon dioxide for the life of the building, in this case a difference of 306 tonnes of CO2.
In my post of a few years ago asking, Concrete: Can it be Green?, a commenter responded:
Concrete isn’t a benign substance, but then I don’t know what human-made material IS, and our urbanized & urbanizing reality dictates that we use it. I love wood, but there are just some structures you just can’t build out of sticks!
KLH and Thistleton Waugh demonstrate that you can do a lot more than we thought. With so much wood going to waste because of pine beetle infestation, it is a shame that they don’t do this in North America.