Repairing large holes in drywall—anything over six inches—is different from fixing a small hole in drywall. Small holes can be patched over with drywall tape or a self-adhesive drywall patch, but large holes need a more rigid material to span over the larger opening.
The simplest solution is also the best: cutting a patch from another piece of drywall and securing it with wood backing strips and drywall screws. Once the patch is in place, tape and “mud” (apply joint compound) over the seams, just like when installing new drywall. The result is a permanent repair that is just as strong as the surrounding surface, and, if you finish the patch carefully, it will not be visible.
Prepare the Opening
Trim the edges of the hole to create straight sides and a square or rectangular overall shape. Use a framing square and a pencil to mark cutting lines on the drywall. Then cut along the lines with a drywall saw.
Install the Backing Strips
Cut two pieces of lumber or plywood a few inches longer than the long sides of the hole (if it’s a rectangle). Place one piece into the hole, parallel to one of the long sides, so the strip is centered over the drywall edge (half is behind the drywall and half is exposed).
Secure the strip with drywall screws driven through the drywall and into the strip. Keep the screws about 1 inch from the drywall edge, and space them about 6 inches apart. Repeat the same process to install the other backing strip along the opposite edge of the hole.
Install the Drywall Patch
Cut a piece of drywall to fit the hole. It doesn’t have to be a snug fit, but the seams should be not more than about 1/8 inch wide. Position the patch over the hole and secure it to the backing strips with screws. Keep the screws about 1 inch from the edges of the patch and space them 6 inches apart.