Repairing Sheathing

Once the old roof has been torn off, repair any damaged sections of sheathing. Inspect the plywood and planks; repairs are usually relatively easy and quick.

A roof does not have to be as firm as a floor, but it should be strong enough to hold the roofing without sagging. If the roof has dips that can be spotted from the ground, be sure to make repairs in those areas.

If the edge along an eave is rotted or otherwise damaged, be sure to inspect the fascia board and rafter ends as well. This is a common location for rot. Replace any damaged fascia boards. If rafter ends are rotted 2 inches deep or less, you may be able to solve the problem by applying liquid wood hardener. Or cut away the damaged area and install a "sister" piece alongside the rafter. Then cover the rafters with fascia and soffit boards. Repair sheathing with plywood that is the same thickness as the existing sheathing if possible. Pressure-treated plywood is affordable and will prevent rot.

Checklist

Time
Once you have the materials, less than an hour for most sheathing repairs

Tools
Tape measure, circular saw, framing square, layout square, chalkline, drill, hammer, screwdriver

Skills
Basic measuring and cutting

Prep
Remove shingles, flashings, and nails

Materials
1/2-inch or 3/4-inch plywood or OSB (oriented strand board) to match the existing sheathing, 2X6 boards, 16d nails or 3-inch deck screws, 8d nails or 2-inch deck screws, underlayment