You had a roof leak and wound up with a water stain on your ceiling. You got out the touchup paint, gave the stained area a quick coat of matching color, and, in only an hour or so, the paint became completely dry. To your dismay, however, the stain returned as soon as the paint dried. Well, it doesn't have to be that way. Using a few simple precautions you can rid yourself of stains forever - easily and inexpensively.
A roof leak isn't the only cause of water stains. Flooding and pipe leaks can cause a similar result. The technique required to make a good repair is the same in each case.
You can use any good "stain-killing" paint on just about any ceiling or wall surface and completely hide a stain - no trick here. However, it is better to take a few precautions beforehand. Not doing so could mean peeled paint a few days, weeks or months down the road. No sense in doing the job twice. Doing it right the first time can save time and aggravation. Here are a few things that you need to do before you repaint a water-stained ceiling: Clean the surface, dry the area out completely and check the stained surface (once it has been dried) to determine if it is stable enough to hold the new coat of paint.
CLEANING THE SURFACE
Make sure the area to be painted is clean and free of oil, grease, dust, wax and dirt. The degree of cleanliness is not always easy to determine by visual inspection. Sometimes you must simply rely on the cleaning process. For example: a coat of wax might be cleaned from a surface and disappear without notice, hidden within the foam of a spray cleaner. Bottom line: Clean whether it looks like it needs it or not.
If mildew exists, use our famous formula to rid the area of the black, smelly stuff. Here's what to do: Mix one-third of a cup of powdered laundry detergent and a quart of liquid chlorine bleach into three quarts of hot water. Add the bleach to the water first and then the detergent. Mix the contents thoroughly and pour into a spray bottle. Next, spray the concoction onto the affected surface. Re-spray as often as possible to keep the surface slightly wet until the black spores turn white. Then rinse with fresh water and towel-dry. What you believe to be mildew might, in fact, be a black algae. As a precaution, take an extra step. Once you've used our mildew formula, re-clean the area with an algaecide. Stop by your local pool store - that's where you'll find it.
Caution: Algaecide is a pesticide and is poisonous. Be careful to exactly follow the manufacturer's precautions.
Plain old-fashioned household ammonia is another great cleaner. If no mildew exists ammonia is your very best bet.
DRYING THE SURFACE
This step is more critical than cleaning. Paint simply will not stick to a wet surface, no matter how clean it is. Plus, you can't test to be sure that the surface is sound until it is completely dry. Naturally, you will first want to ensure that the source of the leak has been completely repaired. If a winter leak is repaired after the rainy season, the leak should be water-tested to be certain that it was properly repaired.
Recently, we had our roof patched. We made a minor modification that required about 50 feet of repair. It rained the following day and water poured through. The patch was redone and it rained again. The second time the repair held. We were fully prepared to water-test the area after the second repair. We hadn't thought of doing so after the first one. Live and learn.
Anyway, once the leak is stopped and the stained area has been thoroughly cleaned, you must dry the area completely. A hair dryer is ideal for small areas (a foot or so in diameter) or a heat gun can be used for larger ones (up to several feet). If an area is very wet, a dehumidifier might have to be used. Whatever it takes, keep in mind that paint will not stick to a wet surface.
BEING CERTAIN THAT THE SURFACE IS SOUND
Wallboard that has been wet sometimes becomes seriously damaged - not every time, but often enough to warrant taking an extra step. Perform the following steps to ensure that the surface to be painted is sound. You will need a short length of duct tape and a razor knife: First, use the razor knife to cut an "X" in the center of the damaged area. Next, firmly press the duct tape against the center of the X. Finally, pull the tape away. If the surface is secure it will remain in place. If damage has occurred, the surface will pull away with the tape. If the surface pulls away you will need to replace the damaged material and then paint. Again, you can paint if you wish. However, chances are you will be back at it again.