Holes in drywall are easily repaired if you use the right material and techniques. A secure fit is necessary to prevent future shifting and cracking in or around the patch area. Backing supports and keeps the drywall patch piece in place. Any type of wood can be used for backing, but shims or lath are an ideal choice of material. Shims are 1-to-2-inch strips of pine that are wedge shaped and about a foot long, and that are usually no thicker than 1/2 inch at the thickest point.
Prepare the Hole
Cut the hole’s edges to create straight and even sides using the drywall keyhole saw. Make the hole a little larger if necessary, straight and even sides make it easier to fit the replacement drywall piece.
Smooth the drywall edges around the hole using the drywall rasp. Drag the rasp along each cut edge removing any lumps or loose chunks of drywall material from each edge of the opening.
Remove excess paper facing material from the outside edges of each side of the opening. Cut the excess facing paper with a razor knife being careful not to remove any drywall from the sides of the opening.
Measure the two long sides of the opening that are opposite each other with a tape measure. Write the measurements lightly on the wall next to each measured side with a pencil.
Install the Shim Backing
Cut two lengths of shim, 4 inches longer than each opening measurement. Use a wood saw to cut the shims at the appropriate length. It is important that each shim piece is at least 4 inches longer than the opening measurement.
Maneuver the shim pieces completely inside the opening and into the space behind the drywall. Position each shim piece along the cut edge of the opening so that half of the shim’s width is behind the drywall and half is visible in the opening.
Screw the shims in place by pulling them firmly against the backside of the drywall and inserting a drywall screw through the drywall adjacent to the opening and into the shim. Tightening the screw sucks the shim firmly against the backside of the drywall. The head of the screw should be set so it does not stick up above the surface of the drywall. Insert screws above, below and along the side of the opening through the shims every two or three inches, or as needed to secure the shims firmly to the existing drywall.
Install the Drywall Patch
Measure to determine the dimensions of the patch opening. Transfer those measurements to the backside of a piece of drywall using a pencil and straight edge.
Cut the drywall along the pencil lines with a razor knife. Score the backside of the piece of drywall deeply enough to break through the paper baking. Gently break the drywall along the cut lines, folding the drywall along the cut line.
Turn over the piece of drywall and gently cut through the front facing paper along each fold. Remove and discard the excess drywall pieces. Remove any excess drywall from all of the cut edges with the drywall rasp.
Place the drywall patch into the opening; hold it in place while you insert screws through the drywall patch and into the shim backing behind the patch. Insert a screw every two to three inches along the cut edge to secure the patch.
Apply drywall joint tape with drywall compound to each seam of the patch and allow the tape to completely dry. Continue to coat the entire patch with thin layers of drywall compound. Allow each coat to dry completely, and lightly sand to remove excess drywall compound.