How to Repair Water-Damaged Bathroom Drywall

Water damage in a bathroom is a ticking clock. Because bathrooms are inherently humid environments, drywall that has been soaked through rarely dries out completely on its own. Left unaddressed, it becomes a breeding ground for mold and structural rot that will eventually compromise your wall studs and finishings. Successful repair requires moving past the surface level. You are looking to cut out the rot, expose the framing to verify it is dry, and replace the board with moisture-resistant material. Do this correctly and the wall will be as sturdy as the day it was framed; leave behind hidden moisture and you will be repeating this project in six months.

1. Cut to Solid Drywall. Use a utility knife to cut away loose tape, bubbling paint, and soft drywall. Keep cutting until you reach solid, dry drywall that shows no signs of discoloration or crumbling.
2. Check Studs for Moisture. Remove any damp insulation or debris from the wall cavity. Inspect the wall studs for signs of rot or persistent moisture before proceeding.
3. Cut Your Patch Tight. Measure the opening and cut a piece of moisture-resistant green board or cement board to fit. Aim for a snug fit with a sixteenth-inch gap around the edges for the joint compound.
4. Screw Patch Flush. If the edges of the patch do not fall directly over a stud, screw wooden backing strips to the existing studs inside the cavity. Screw the new drywall patch firmly into the studs and backing strips.
5. Feather Edges Smooth. Apply fiberglass mesh tape to the seams. Apply a thin layer of moisture-resistant joint compound over the tape, feathering the edges outward to blend with the existing wall.
6. Prime and Paint. Once the final coat of mud is dry, sand the area smooth with fine-grit sandpaper. Apply a high-quality moisture-resistant primer followed by bathroom-grade paint.