How A Flooded Basement Affects Drywall
Any time your basement floods, it creates problems. Not just the abundance of water, but the rise in humidity and moisture can set the stage for problems such as mold. Moldy rooms are the most common water related problem with basements, but if there is a close second, it would have to be the effect of water on your basement drywall.
Of course this happens if the basement has been finished or partially finished, and is a problem because of all the floors in your home, the basement is the most prone to water damage, and will in all likelihood see the most water if and when a leak or flood happens. Now granted, it is usually only the bottom few inches of the drywall that is damage, but that is usually enough to ruin the drywall completely, and the repairs involved may be considerable both in time and expense.
Once water gets into drywall, you begin to see any number of effects, from softening of the drywall, to water stains, and the drywall may even begin to swell and come apart. Worse, you now have water within your walls, which means that the walls will need to be opened up in order to fully negate all of the basement water damage which may have occurred.
The good news is that you probably will not have to replace all of the drywall in the water damaged basement. Drywall may be effectively cut and patched, and once it has been filled and painted, it will look just as it did before there was a problem. Of course it should go without saying that no drywall repairs should be affected until the source of the flooding has been addressed, since there is little point in making repairs when damage is only going to be reinflicted.
Water damaged drywall should be cut away about a foot above the water line, the highest point of the water damage. Use a jigsaw to cut through the drywall. You will need to use a prybar and hammer to remove the drywall from the studs. All nails and screws should also be removed.
Make all measurements of the opened area, and then cut a piece of drywall to fit exactly, or as exactly as possible. Attach the drywall using galvanized screws wherever there are studs behind it. Screws should typically be applied every eight to ten inches. Make sure all ends meet correctly.
Use drywall tape over the seams between the boards, and then spread joint compound over the tape using a drywall knife. Make sure it is smooth and flat. The compound should set for about four hours, and then properly sanded down in preparation for painting. Apply as many layers as needed to get the desired effect before paint goes down.