Interior walls with water damage can easily grow mold and will have to be repainted. Unfortunately, drywall does not withstand water damage well. Drywall is relatively inexpensive, so it is best to replace the damaged sections. Not only will you have a completely new surface to paint, but you’ll also be able to open the wall cavity to make sure that the wall is completely dry.
Step 1: Wearing a high quality face mask and gloves, cut away the water damaged sections of drywall with a drywall saw. Discard the water damaged drywall, following any disposal requirements set by your waste management company.
TIP: If the drywall has begun to grow mold, be sure to clean the interior wall cavity and allow it to dry out completely before continuing. Wet walls should also dry completely before drywall is added to the wall cavity. Having a strong fan circulate the air will speed drying times and reduce the chance of greater water damage.
Step 2: Extend the cut away area that encompasses all of the water damage so it begins and ends on a stud with the drywall saw. You can use a stud finder for this step. Also remove any fasteners sticking out from the studs with a screwdriver or hammer.
Step 3: Cut a patch to fit the water damaged area with the drywall saw. Lift it into place and secure the drywall to the studs with drywall screws spaced every 8 inches around the vertical perimeters.
Step 4: Screw into any studs that the drywall spans, spacing the screws every 14-16 inches.
Step 5: Fill the screw heads with joint compound using a putty knife. Place sticky drywall mesh on any drywall seams, with half of the width of the drywall tape on either side of the drywall.
Step 6: Using a 6 inch drywall putty knife, apply a layer of joint compound over the mesh drywall tape. Try to feather the edges to conceal the seam. Allow the joint compound to dry.
Step 7: Sand the joint compound patches until they are smooth and blend with the rest of the wall. To cover the drywall mesh tape, you may have to add and sand several layers of joint compound to fully conceal the drywall seam.
TIP: Now is the time to add any wall texture, so the patch will match the areas of the wall not affected by water damage.
Step 8: When the wall is dry and properly patched, cover the entire wall, not just the patch with primer, then paint the wall as desired.
TIP: If your paint matches exactly, you should only have to paint the wall with water damage. Of course, if you can’t find matching paint, you will have to paint the entire room.