Remove old, peeling finish before restaining wood deck

Q. My deck, made of pressure-treated wood, was finished about two years ago with a solid-color, oil-based stain. The stain is peeling to the bare wood, especially when I try to scrub off mold stains. How can I refinish the deck so it won’t peel? Can I use a rotary sander to remove peeling stain, do I need a primer, and how do I clean it?

A. Many experts agree that the best finish for pressure-treated wood is a semi-transparent stain. This stain penetrates into the wood and generally won’t peel, unlike some solid-color stain, which basically lays on the surface of the wood like paint and can peel and flake under some conditions.

Semi-transparents usually don’t last as long as properly applied solid colors, often about three years for semis compared with five years or more for top-quality solids.

Unfortunately, you can’t use a semi-transparent stain or try a solid color again without removing all the old, peeling finish.

You should definitely not use a sander or scraper to remove the old finish, since breathing particles of pressure-treated wood can cause several serious respiratory diseases.

The best bet is to remove the old finish with a good chemical remover.

When using any chemical stripper or deck-finish, it is extremely important to carefully read the directions and cautions and follow them. If in doubt about any part of the process, it is best to have an experienced deck contractor do the work.

After removing the old finish, the wood should be cleaned thoroughly and allowed to dry out. Primers are not needed with stains.

If the deck develops mildew or mold stains, they can be removed with any good bleach-type deck cleaner. Again, read the directions carefully; some cleaners require scrubbing, a few are just sprayed on, allowed to work for a given time, then are flushed off.

If you like the new finish on your deck, save the label from a stain container and use the same product when re-coating.

Q. Our cat sneezed on a painted wall, leaving stains that I don’t know how to remove. This is not a joke, the cat was sick.

A. Most wall paint is washable to some extent, some more than others.

When stains do occur on a painted surface, it is always best to try and remove them immediately; sometimes some warm water on a well-wrung-out sponge will do the job for stains of the type you have.

Since the stains are old, mix a teaspoon of dishwashing detergent in a pint of warm water. Use a clean sponge, dip it into the solution, and wring it out thoroughly. Wipe over the stain gently; too much rubbing might remove the paint.

If this doesn’t work, a touch-up is the best bet. If you have some leftover matching paint, or have saved the label and color information from the original paint containers, this shouldn’t be too difficult.

If the stains have left a residue, sand the area lightly with 200-grit sandpaper until it is smooth. Apply a coat of a stain-killer primer to keep the stains from bleeding through the new paint. When the primer is dry, carefully brush fresh paint over the stained area. Smooth out the edges so they blend into the rest of the paint and let dry. A second coat of paint might be needed to fully blot out the stains.

The touched-up area probably won’t exactly match the rest of the wall, but should be close enough to be hardly noticeable. If you are still not satisfied, you will probably have to paint the entire wall or room.