Posted on August 1, 2011 by Scott Gibson
Thaddeus Cox’s 1944 Cape Cod in Portland, Oregon, has a roof that needs some attention. Not only is the roof under-insulated, but it’s currently covered in two or three layers of asphalt shingles installed over the original layer of cedar. Roof sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen.
consists of 1-in. thick boards.
The International Energy Conservation Code recommends R-38 for the roof in this Climate Zone 4 house, far more than the R-11 batts Cox thinks are currently in place.