As we continue to watch a zero-energy home get built in my hometown of Boulder, Colo., I’m digging the opportunity to learn more about building materials that I’ve seen in finished form but never in process. I like the new perspective.
Recently I took my camera over and caught the crew pouring concrete into foam panels called Insulated Concrete Forms (ICFs). While I was there, Scott Rodwin and Ron Flax of Rodwin Architecture talked about why they like these ICFs. They have great thermal mass, strength, and sound and wind protection. (All key…the home is being built in one of Boulder’s famous wind alleys, where it can blow up to 130 mph.) And because they’re shipped flat and assembled onsite, there’s much less construction waste.
Ron was happy because the foam insulation on either side of the concrete kept it cool and manageable on a hot summer day, when pouring concrete (especially in arid Colorado) can be a nightmare. “This is essentially a concrete wall, with the blessings and curses of concrete,” he told me.
Scott and Ron chose Quadlock panels because they allow for easier engineering—which, Ron adds, “is helpful when working with a house as structurally complex as this one.” The house is three stories, on a hill, with huge windows and a lot of steel. All this made advance planning crucial. “When planned in advance, things like windows, vent pipes, electrical conduits and attachment points are super easy with ICFs,” Ron told me. “But when thought about too late, they are problematic at best, and nearly impossible at worst. While it’s relativity easy to carve out the foam and install wiring and plumbing inside the rooms, exhaust vents, moving windows or any interior-to-exterior penetration is another story entirely.”
On the scene? All was well. Panels up, concrete in, no punctures necessary.