How to Replace Rotten Wall Sheathing Inside

Turn off the electricity to the room. Perform the work during daylight hours and run an extension cord to the room if you require additional light or power. During replacement of the interior wall sheathing and cleanup, you will expose electrical outlets and wiring that could shock you if they remain live.

Remove every face plate for light switches and electrical outlets using a screwdriver. Set aside to clean and reuse if they are still in solid condition.

Turn off the furnace or air conditioner and open a window to allow ventilation during the repair. Set a box fan in the window, pointing outward, if you have an available extension cord. Cut a sheet of plastic to hang, covering the doorway and block vents or registers to prevent dust, debris and especially mold spores from getting into uncontaminated areas. Highly airborne, by definition mold accompanies rot; preventing excess movement during cleanup is important. Use duct tape, thumb tacks or similar methods to hang the plastic.

Remove the wall sheathing according to the type of material. Watch for wiring or ducts as you work to avoid damage. Rigid boards or paneling pry away easily, starting at a rotten area and working back with a pry bar or the claw end of a hammer. For drywall, work similarly, removing the material in chunks rather than large sheets since the drywall will prove more soggy or crumbly. Throw the wall covering waste immediately into a large plastic trash bag to contain the mess and any mold. Work back to good wall covering, ending on studs well into healthy wall.

Pull all insulation present out of the wall. Pry rigid foam insulation away or simply tug on fiberglass. Throw the insulation away -- trying to save it isn't worth the cost as it is hard to clean. Remove any exposed nails, screws or staples that held either the wall covering or insulation in place.

Inspect the uncovered wall framing. Identify and correct any current sources of moisture; small leaks can be sealed with a bit of caulk. Large holes may need repair from the exterior. Consult a professional for extensive exterior repair.

Look closely for mildew and mold. Mildew especially, which is a type of mold, may resemble dirt or ink. Spray a solution of bleach and warm water, at a ratio of 10 parts water to 1 part bleach, on a small patch of suspected mold or mildew to test. If it lightens visibly, it's mold or mildew.

Spray the entire surface of the wall cavity down with a light but steady coat of the bleach water solution. This kills the mold spores before removal as well as weighing the spores down to discourage release into the air.

Scrub over the surfaces with a soft-bristled brush. Keep a bucket of clean bleach water to rinse the brush in continuously. Cross-contamination of surfaces is a concern with mold, so keeping your brush clean as much as possible is best.

Remove the rotten and moldy debris after all rot is removed and mold cleaned away. Pull the plastic doorway down as well to allow air circulation inside the room. Allow the exposed wall cavity to dry thoroughly -- 24 to 48 hours is ideal -- to avoid encouraging a resurgence of mold growth due to the dampness once it's enclosed.

Replace insulation inside the wall. Cut rigid foam insulation to fit between the studs, full length from ceiling to floor, using a utility knife. Glue and attach the insulation against the rear of the wall cavity. Install fiberglass insulation by cutting with a utility knife or scissors and pressing into place or stapling the vapor barrier to the front of the studs. Cover the entire surface of the opening with a sheet of plastic, which forms another vapor barrier. Staple through the plastic to secure to the face of the studs. This will prevent future wall sheathing rot in this location.

Cut and install replacement wall sheathing. Measure and cut sheets of paneling and glue before attaching to the wall. Reinforce with nails driven into the studs beneath. Cut drywall by scoring the material and snapping to break. Hang horizontally, driving screws through the drywall into the studs. Tape, mud and sand all joints and screw heads before priming and painting. Install other wall coverings according to directions.