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Our little house project involves a lot of concrete. How much is a lot? Well I think I heard an actual number of yards at some point, but it gave me a mild panic attack and I’ve now blocked that number out. Plus, unless you’re a concrete contractor you probably don’t relate to yards of [...]
Our little house project involves a lot of concrete. How much is a lot? Well I think I heard an actual number of yards at some point, but it gave me a mild panic attack and I’ve now blocked that number out. Plus, unless you’re a concrete contractor you probably don’t relate to yards of concrete.
Because we’re on a hill (a gentle hill, but still a hill), to build our house we need a series of retaining walls. So when people see our plans for the first time, one of top-three initial comments is something like, “holy crap, how long are those walls?”
The back retaining walls will stretch about 150 feet, give or take. These are eight feet tall and roughly 10″ thick. Then there are a series of lower walls…maybe 70 additional linear feet that wrap around the southeast side of the house. A couple of these are pretty impressive–16 inches thick so they double as seating for the outdoor spaces.
The majority of the concrete will be board-formed. If you’re not familiar with this technique I’ll attempt to briefly explain it. Most modern concrete walls are built with smooth sheets of coated plywood. When it’s setting, concrete of course picks up whatever texture is next to it. So smooth plywood gives a smooth wall.
Board-forming, on the other hand, is how concrete walls were formed way back when. It involves building the forms out of timbers/wood planks, rather than plywood. So when the forms are pulled off, you’re left with a wall that now has wood grain, as well as more texture on the concrete from where it seeped through the wood joints.
Generally speaking, board-forming is rare. Not impossible to find, but not something most concrete contractors do on a daily basis. So yes, it’s modestly more expensive to build walls this way. We’re crazy about how this looks though, and definitley looking forward to the walls being built, likely in the next couple of weeks.
My sense of things is that board-forming is a bit more common in the northwest of the country. There are great examples from Cutler Anderson and Bohlin Cywinski Jackson in particular. And closer to home, Nystrom Olson is doing some really impressive stuff.
Matt, our architect, is I think beside himself with anticipation about the walls. The other night on the phone he said some version of, “I can’t even let myself think about those walls. They’re going to be very cool.”