Q. We used exterior high-gloss enamel to paint the wooden posts that support the roof of our open-front porch. Before painting we sanded and primed the wood, but now the bottom of each post is peeling, with the paint coming off in large chunks. I think moisture collecting at the bottom may cause this. What can we do to prevent it and eliminate the need for repainting each year?

A: Moisture most probably is causing your problem, and using a high-gloss enamel makes the problem worse because it seals the surface more than a latex paint will. The moisture probably is getting inside the post and saturating the wood behind the paint.

After scraping the paint off down to the bare wood, do a thorough job of caulking all around the base down to the base of the post to keep water from seeping from underneath. Use a good grade of butyl rubber or silicone rubber (the paintable kind) compound, and be sure you also caulk all joints and seams in the post itself. Then prime and paint again.

Q: I want to remove rust stains from my concrete patio. My local hardware store suggested covering the stains with sand, then pouring bleach over the sand, but this did not work. They also suggested a strong acid etching solution (sold for use on concrete), but I am afraid to try this because it might kill the plants and shrubs nearby. Can you suggest a safe and effective way to remove rust stains?

A: I have two suggestions that sometimes work -- but rust stains are hard to remove from concrete so I can't say for sure whether these methods will work. First, try removing the stains by treating with oxalic acid. It comes in crystal form. Mix the crystals with hot water, then scrub this on over the stain. Allow to dry, then rinse off with plain water. This bleach often works on rust stains. If this doesn't do the trick, try a regular rust-stain remover -- the kind sold in hardware stores for use on rusty metal. Spread on liberally, then scrub off according to the directions on the container.

Q: The outside of my house is covered with cedar shakes that were stained a dark burgundy color when the house was built in 1955. I would now like to stain them a much lighter color -- white or close to it. Can this be done and, if so, what should I use?

A: To go from a dark color to a much lighter one, you will have to use an opaque paint, or one of the so-called heavy-bodied shingle stains. These are actually more like a paint than a true stain in that they have enough pigment to cover a big change in color, and they are better for the shingles than a regular house paint. Heavy-bodied stains come in oil or latex base, but you probably will find the latex easier to work with. You will need at least two coats. I suggest using one with some color in it -- not straight white.

Q: Our kitchen counter has a wooden chopping block built into the top. Over the years this has become stained and scratched. How can it be restored and refinished, and still used as a chopping block?

A: A wooden chopping block is best not covered with a finish of any kind; it should be scrubbed regularly to keep it clean. If yours if badly stained and worn, sand with medium grit paper and finish with a finer grit paper, then scrub it with a detergent solution and rinse thoroughly. Some people prefer to seal the surface with a thin coating of boiled linseed oil. Heat the oil carefully in a double boiler and apply to the wood while still warm. Let it soak in for about 15 minutes, then wipe off the excess with a clean cloth. Repeat three or four times, or until no more oil is absorbed, then buff with dry cloths.