Exterior, Cabin Building Type, and House Building Type “If you look closely at the concrete wall, the curvature is based on one really simple formal move,” says Massie. “In front, the roof is about 11 feet high, and in back, about 9 feet. If you could imagine just pinching the back of the building, that linear distance would have to go somewhere, hence the curve.” That arc continues inside as the wall nearest to the guest sleeping area. “It’s really interesting to feel that wall dimpling toward you,” says Wooten. “It changes as you walk from the bedroom to the guest bath—it starts with a dramatic curve and gradually flattens out.”  Photo 7 of 12 in A Hybrid Prefab Home in Upstate New York