If your roof has water damage, you will need to remove the drywall and let the inside of the roof dry out. If not, mold may grow inside your ceiling. Correct the initial cause of the leak to avoid future damage. If you are not sure where the leak is, ask a professional roofer or plumber to inspect your home. If you notice mold development anywhere in your home, hire a professional mold-removal contractor to get rid of it immediately.
- Push gently over the area to determine the magnitude of water damage. You have to remove and place sections of plasterboard that are soft or severely arched.
- Use a knife to mark a line around the entire damaged area.
- Break apart the area within the score lines with a hammer and remove all damaged plaster.
- Reach inside the hole to find the wooden posts closest to the edges of the hole. Use the knife and hammer to remove the plaster up to the wooden posts, leaving a square or rectangular hole in the ceiling.
- Remove some gypsum (drywall) panels in the middle along the uprights on each side of the hole (leaving half of the exposed beam showing to allow for installing screws to secure the new piece of gypsum).
- Set fans and dehumidifiers up to dry the interior ceiling area. If the outside air is dry, open the windows and doors to let fresh air in. Depending on the magnitude of the water damage, it could take several days for everything to dry completely. The goal is to avoid the development of mold after closing to the ceiling. Do not proceed until the interior of the roof is dry.
- Cut a new piece of plaster to fit the hole. Use drywall screws and a drill to attach to wood. Install screws every four to six inches along the outer edges of the hole where the wooden crossbars are. This will strengthen the connection between the existing roof and the new part.
- For normal ceiling, use a 6-inch gypsum knife to compound on each joint. Place a section of drywall tape over the composite and wipe it flat. Fill in all heads from the screws. Wait for the joint compound to dry completely (usually 24 hours). Use a 12-inch gypsum knife to apply a second layer of compound over the entire area, this time leaving a thick, soft layer. Allow to dry and then sand the area with 150 grit sandpaper.
Prime and paint as normal. If you notice rusty or yellowish water stains showing through the composite joint, use a special concealed primer (available from hardware stores). Ask the staff or check the label to verify the primer is specifically designed to conceal water stains.