How to Remove Siding and Repair Sheathing
If you've found a section of sheathing that has succumbed to rot, it's in your best interest to fit it right away.
Before installing new siding, you will need to remove some of the old siding. Unfortunately, this can reveal rotted sheathing. If you come across a bad patch, don't ignore it. The rot can get worse and even spread. However, replacing a small section of sheathing is fairly simple. Below, we show you how to get the job done in just four steps.
Before you start, determine which wood pieces will stay and take care not to damage them while removing siding. A flat pry bar and hammer will take care of most of the job, but special tools can help speed up the removal.
Have a plan for disposing of the old siding. Unless the area to be stripped is small, you will probably want to rent a roll-off trash container. Arrange to have it delivered as close to the site as possible and create plank paths for wheelbarrows so you can fill the bin without damaging your yard. Place drop cloths or plastic sheeting on the ground to minimize cleanup later.
Plan to cover the bare sheathing with building wrap on the same day that you remove the old siding.
Step 1: Find Stud Edge
If a section of sheathing is rotted or otherwise damaged, cut out an area that spans from stud to stud. To find the edge of a wall stud, drill a finder hole near a sheathing nail. It may take a couple of holes to find the edge.
Step 2: Remove Damaged Section
Cut out the rotted section along the inside edge of adjacent studs. This is easy work with a reciprocating saw, using the side of a stud as a guide. Remove the sheathing and any nails.
Step 3: Attach Nailers
Where you cut alongside a stud, cut 2X4 nailers several inches longer than the opening's height. Hold each piece tight against the sheathing above and below and flush with the stud. Attach each nailer by driving 16d nails or 3-inch deck screws every 12 inches or so.
Step 4: Drive New Sheet
Cut plywood (pressure-treated, to be safe) about 1/4 inch shorter and narrower than the opening. Use shims to position it with 1/8-inch gaps all around. If needed, attach strips to the nailer so the patch is flush. Drive 2-1/4-inch deck screws about every 8 inches.