Painting Over Water-Stains

A water-stain is the discoloration that exists on your wall after it gets wet. These stains are usually caused by a leaking roof or pipes and typically have a yellowish-brown coloration which is most prominent along the edge of the stain.

The first thing to do is fix the root cause of the water leak. You don't want to spend time and money fixing a water-stain only to have it reoccur from another leak.

Once you've fixed the cause of the leak, you can repair the water-stain. If the sheetrock or wall is severely damaged, then you may need to replace the sheetrock. Otherwise, simply painting over the water-stain should suffice. However, you must use a special primer in order to block the stain from bleeding through to the surface again. The best stain-blocking primers are alcohol-based. My favorite is called "BIN", a product made by Zinsser. It smells pretty bad, but dries in 45 minutes and will block any stain from bleeding through. (It will also block lipstick, smoke-stains and marker). The next best primers are oil-based. Zinsser makes a product called "Cover Stain". It doesn't work quite as well as BIN, but is still effective. Many companies make water-based primers they claim to be "stain-blocking", but in our experience, water-based primers are not nearly as effective as alcohol or oil-based products.

Tip: use a disposable brush or roller to paint the alcohol or oil-based primer. It is far better for the environment to throw away a cheap brush then to use solvents to clean the brush.

If you don't use a special stain-blocking primer, the stains will continue to bleed through your paint to the surface. Each time it will take couple days, but it will keep coming through. So just throw a coat of BIN over the stain and re-coat with the wall paint.