How to Level a Plywood or OSB Subfloor Using Asphalt ...
Dec 10, 2011· Shingles would still be needed, but I could have gotten away with fewer, resulting in less time and weight. One inch of shingles is a lot of shingles, and my floors were off in more than one direction in some areas, so the upper layers of shingles were often cut at angles to match the slope.