Step 8 · Repair the Access Wall
After confirming there are no leaks, you can repair the access wall. Re-insert the piece of drywall you cut out earlier. Secure it by screwing it to the studs or by adding small wood backing strips for support if it's not between studs. Apply drywall tape over the seams, then spread a thin layer of joint compound over the tape with a putty knife. Allow it to dry completely as per the manufacturer's instructions. Apply two to three more coats, sanding lightly between each coat, until the patch is smooth and flush with the surrounding wall. Prime and paint to match.