Repairing Sheathing

Examine the plywood, planks, fascia, soffits, and other areas of sheathing that may need to be repaired, then follow the steps to get it fixed.


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.


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

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

Basic measuring and cutting

Remove shingles, flashings, and nails

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

Step 1

Check for damage. Look for places where the sheathing is rotted or discolored from water damage. Poke with a screwdriver; if it goes in easily, the wood is rotted. You can also inspect from inside the attic. Shine a flashlight at the sheathing and rafters and poke with a screwdriver.

Step 2

Remove the damaged area. Use a chalkline or a pencil and framing square to mark a rectangle around the damaged area that spans from the inside of a joist to the inside of another joist. (Do not attempt to cut along the center of the joists.) Use a circular saw to cut out the rectangle.

Step 3

Pull out the damaged plywood and inspect the rafters below. If they are slightly rotted, install long sister rafters, made of boards the same width as the rafters, alongside them instead of the nailers shown in the next step. Attach the sisters from inside the attic. If the damage is extensive, call a carpenter for advice.

Step 4

Attach pieces of 2X6 alongside the insides of the rafters to provide a nailing surface for a plywood patch. Attach the nailers with 16d nails or 3-inch screws.

Step 5

Cut a patch to fit snugly (but not so tightly that you have to pound it into place). Set it in place and drive 8d nails or 2-inch screws into the rafters and nailers.

Step 6

Cover the patch with underlayment. The patch and the surrounding sheathing should look and feel fairly level.

Comments (2)
sgfsd wrote:

Download over 16,000 WOODWORKING PLANS at here Woodworking guide offers anyone of any skill level the ability to build amazing projects. The guide is extra helpful because it offers more detailed explanations, videos and blueprints then your typical woodworker magazine . Hope it will help you next time !

6/9/2016 01:41:13 PM Report Abuse
carold362436 wrote:

The picture guide is very helpful to actual showing how the job is suppose to be done

4/22/2012 05:37:24 PM Report Abuse
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