If a water leak damaged your drywall, you'll want to repair or replace it. Otherwise, mold may grow on the drywall before it has a chance to dry out completely. Plus, you don't want to look at an ugly water stain. You might be able to fix the problem yourself, or you may be better off calling a contractor if you're not handy with tools. The first step is to determine the extent of damage.
Inspect The Drywall
Water damage takes different forms. If you're lucky, you'll only have to deal with an ugly surface stain. However, since drywall is so porous, there's a good chance the water will have soaked into the drywall material and caused some damage. In addition to looking for water stains, look for bubbles and bumps on the drywall that indicate swelling due to water absorption. Also, press on the drywall to see if it feels smooth and hard or if it is bumpy, soft, or crumbly. Next, look for signs of mold. Keep in mind, if the back of your drywall is wet, or if the space between the walls is wet, the back of your drywall may be covered with mold. If you've had a big leak, it's worth the effort to remove a small part of the drywall so you can see what is going on between the walls.
Cover A Water Stain
If the drywall appears to be in good shape except for the surface stain, all you have to do is cover the stain. House paint won't work because the stain will eventually bleed through. Instead, buy a can of drywall stain sealer at the home improvement store. It goes on just like paint. Once it's dry, then you can apply a new layer of regular paint and the drywall will look good as new.
Repair Damaged Drywall
If part of the drywall has soaked up a lot of water and it looks warped and bumpy, then the best way to fix the problem is to cut out the damaged area and put in a new section of drywall. If you just seal the stain, the wall will look bumpy when you paint it. The bumps appear because the drywall expands when it soaks up water. Then when the water dries up, the bumps get hard. If the bumps are confined to the surface, you might be able to shave them off with a paint scraper and smooth over the top before you seal the stain.
If the damage extends to deeper layers of the drywall, then the only way to get a smooth surface again is to cut out the damage. Cut out a portion that's a little larger than the damaged area. Then cut out a piece the same size from a new sheet of drywall. Fit the new piece in the wall and hold in it place with drywall tape. Next, apply joint compound, or drywall mud, over the tape and repaired area. Use a straight edge to stretch the mud out and make it level with the surrounding drywall. You'll need to act quickly before the mud dries and gets too hard to work with.
If you have several sections of damaged drywall, or if there is a lot of mold growth, you may want to call a contractor for help. You'll have to be meticulous in your work or the wall will not look smooth once you've applied a coat of paint. The last thing you want is to do all that work only to see the repairs showing through the paint when you're finished. For assistance, talk to a professional like Mike's Drywall Service Inc.