There are just a few small problems standing in the way.
TreeHugger loves tall wood construction, and we have always been big fans of Peter Busby of Perkins+Will. (See my interview of him here.) Busby is now working for the Delta Group in Vancouver, proposing a 40 storey tall wood tower. Busby is quoted in an article by Kerry Gold in the Globe and Mail:
“It’s the tallest we think we can technically make with wood today,” Mr. Busby says. “We believe we can go somewhere between 35 and 40 storeys.”
They plan to take energy standards to an unprecedented level, with a rigorously high passive house envelope of about a foot-thick to reduce energy consumption. The building will mostly be made out of cross-laminated timbers (CLT) and dowel laminated timbers (DLT), manufactured in B.C. and culled from damaged trees.
“We want a zero carbon building in operation,” Mr. Busby says.
Busby explains that timber structures are safe and fire retardant because they are designed with a sacrificial layer that turns to carbon, insulating the wood. This is well documented, the way heavy timber buildings have been engineered for a century.
But there are issues. The building codes have just been revised to permit wood structures up to twelve storeys with wood elements exposed, like they are here, and up to 18 storeys when the wood is all enclosed in gypsum board, like it was at the Brock Commons towers. It took years of work to get the codes to this point. There are “peer review” processes that permit variances from the code, but I suspect that 40 storeys with exposed wood is a serious stretch.
There are also zoning issues on this site; it has a height limit of 14 storeys. Sean Pander, the city’s green building program manager and a big supporter of wood construction, says, “Sustainability and low carbon is a city-wide priority, so any application for a project like that is great; it needs to look at that, but also the neighbourhood fit and affordability piece has to be there. That’s the single biggest challenge.”
Really, between the building code and zoning approvals, we could be talking years here. I can’t help but think this is a bit of a stalking horse for the developer, Bruce Langereis, who is certainly getting a lot of publicity like this page in what’s called Canada’s National Newspaper, and who is not putting all of his eggs in one basket.
However, if the public process vetoes it, they will find a Plan B. He suggested a massive block of five-storey buildings that would form canyons, which he says is far less appealing. Later, in an e-mail, he said he’d be “disappointed” if their tower project didn’t pass, though, “as our goal is to demonstrate that traditional tower-base forms that we are accustomed to can be built in a low-carbon manner.”
He’s referring to the Vancouver model building, where there is a base that fills the block at street level and a tower above. I wonder if it is really suitable for wood, which I think lends itself to forms like you find in Paris or Vienna, as I wrote in With wood on the rise, it’s time to bring back the Euroloaf. Even Brent Toderian, who was chief planner and proponent of the Vancouver model, has written that there are different ways to approach these things.
Height and density have a relationship, one that can be over-simplified or mischaracterized, but it’s important to note that they aren’t the same thing. You can have density without height, and yes, you can have height without density.
As I have said before about tall timber, I can’t help but think that 40 storeys is too much of a wood thing.
Source: Tree Hugger