Arrow-right Camera
News >  Features

Home Do-It: Prime before painting water-stained ceiling

Q. Some shingles blew off our roof in a storm and we had a leak that left a water stain on a bedroom ceiling. The roof has since been repaired and we want to get the ceiling back in shape. Can we just paint over the stain?

A. If you paint directly over the water stain, it is almost certain to show through the paint. The best bet is to apply a stain-killer primer first.

Stain-killer primers such as Bulls Eye 1-2-3 and Kilz are sold at most home centers and paint stores. Shellac is also sometimes used to seal stains but is flammable and has more odor than some of the stain blockers.

However, if you just seal over the stain you probably won’t get a smooth paint job. Make sure the stain has thoroughly dried before you apply the primer. If any moisture is present in the drywall or plaster when the sealer is applied, the sealer will probably peel as the moisture forces its way out.

When you are sure the stain is dry, the best bet is to seal the entire ceiling. Of course, it is very important to protect the floor or you are almost certain to get difficult-to-remove drips. Spread plastic sheets on the floor, overlapping the edges and taping them to keep them in place. Extend the floor cover up the walls about a foot and tape it in place.

Apply the primer just as you would apply paint, cutting in the edges with a brush, then using a roller to prime the large inner area. When the primer coat is dry, the stain should not be visible.

Any good latex ceiling paint can be used to finish the project.

When priming and painting ceilings, use a roller with a long handle and work from the floor as much as possible. Cutting in the edges, using a brush, usually must be done from a stepladder. When painting from a stepladder, make sure the paint container and tools are well secured and the floor is adequately protected against spills and drips.

Q. We have concrete steps to our front porch. A big chunk broke off the corner of top step and shattered. Can I repair this myself?

A. To fix the step, you need to make a mold or form to shape the patch and help hold it in place while it dries.

You can make the mold from boards or pieces of plywood held in place with bricks, stones, concrete blocks or whatever heavy objects you can find.

Wipe the inside surface of the mold with automobile engine oil to make the boards easier to remove when the patch dries.

To make the patch, you need a bag of concrete mix, sold at home centers and hardware stores. You’ll probably have to buy a 50-pound or 60-pound bag – much more than you’ll need, but you can mix only enough to make the repair. You will also need a small mason’s trowel, called a pointing trowel, to apply and smooth the mixed concrete.

For best results, also buy a bottle or small can of concrete bonder, a liquid that can be brushed on the broken area or mixed in with the patching concrete (follow instructions on the container).

An alternative method of insuring good adhesion of the patch is to drive several screws into the broken area, letting them protrude about half way. When the patch is applied, the protruding screws grip and hold it in place. Special screws, called Tapcon screws, are available for concrete and are sold at many home centers and on the Internet. A masonry drill bit and power drill is needed to provide pilot holes for the screws.

Put the dry mix in a bucket or other container, add a small amount of water, and stir with a stick or other tool. You want a stiff mix, not a slurry, so only a little water is needed. Pack the patching material into the mold, making sure the entire mold is filled so there are no voids when you remove the boards.

Test the patch with a finger to make sure it is well dried before removing the mold.