Water damaged drywall should always be fixed as soon as possible. If left unattended, mold can develop or water can reach your studs and cause structural damage. Luckily, most water-damaged drywall can be fixed relatively easily.
Find the Source of the Water
Before repairing the drywall, it is very important to find the cause of the water damage. If you repair drywall without fixing the root of the problem, you will just wind up having to fix it again later. Faulty pipes or a leaky roof is often the cause. If you are unable to find the cause, consult a professional.
Cut out the Damaged Drywall and Inspect
Using a utility knife cut a hole around the damaged area of drywall and remove it. Inspect the area inside the wall for any sign of damage to the studs. Studs must be replaced or repaired if there is any sign of water damage. Additionally, look for water damage not visible from the outside. If you see signs of moisture inside the wall, wait until it dries before continuing. A fan can be used to speed up the drying process.
If the damaged area is large, it may be easier to replace entire sections of drywall. However, if the area is small, cut a piece of replacement drywall larger than the current hole. Trace the outline of your piece on the wall around the hole and cut out that outline. Now you have a perfectly sized replacement piece. If there is a stud available, use drywall screws to attach your replacement drywall to the stud. Otherwise, use a piece of plywood as a backer board to screw into.
Tape and mud the seams of the drywall patch using a drywall knife. Once the area around the patch is smooth and blends into the surrounding wall, you can paint the patched area to match the rest of the wall. Periodically inspect the patched area to ensure that the water damage does not return and that no mold forms.
“How to Repair a Water-Damaged Wall : How-To : DIY Network.” DIY Network – Home Improvement How-To & Projects : DIY Network. N.p., n.d. Web. 20 Oct. 2010. http://www.diynetwork.com/how-to/how-to-repair-a-water-damaged-window/index.html.
“Fixing Damaged Drywall Surface | Drywall & Plaster | This Old House.” Home Improvement and Remodeling: This Old House. N.p., n.d. Web. 20 Oct. 2010. http://www.thisoldhouse.com/toh/asktoh/question/0,,216603,00.html.