Q: Three years ago a clear wood preservative was sprayed on my new house and wood deck. This summer we have noticed a green, slimelike coating on areas that remain wet for long periods of time. We want to put on a semitransparent stain and wood perservative again, but before we do I would like to remove the fungustype growth. Can you tell me how to do this?

A: Scrub the affected areas with a mildewcide of the kind sold for use in and around swimming pools and shower areas. This will kill the fungus and remove most of the green slime, but the growth will come back if you don't take steps to correct the conditions which caused it. You say some sections remain wet for long periods. This may mean you will have to improve drainage in these areas or do some pruning of growth to allow sunlight and air to filter through. Fungus will not grow if surfaces are dry and sunlight gets to them.

Q: After 12 years, the original baked enamel finish on my aluminum storm and screen door has begun to chip and peel. I want to repaint it now. What kind of paint should I use, and what preparation is needed before the paint is applied?

A: The preparation will depend on how bad the chipping and peeling are. If most of the paint is still adhering, a light sanding is probably adequate, except where the chips have left a depression. These edges will have to be sanded more to feather out the recess so it won't show through when painted over. If there is a lot of chipping and peeling it may be better to get all the old paint off. Either way, scrape off all the old finish you can, sand the entire surface to get it smooth, then apply a coat of metal primer suitable for use on aluminum. Finish with two coats of exterior trim paint or enamel in the color of your choice.

Q: The hardwood floor in the bedroom of my apartment was scraped, shellacked and waxed two years ago. A few months ago someone spilled a solution of chemical cleaner and Clorox on this floor, which left white spots over half the room. Is there any way to get rid of these spots without scraping the floor and shellacking again?

A: Shellac turns white when water is spilled and not immediately wiped up - and Clorox would bleach it so quickly that I'm afraid the white spots are permanent. You will have to sand the finish off the re-apply shellac to get rid of them. As a rule, the only satisfactory way to do this is to refinish the entire floor, but if there are not too many spots and if you are willing to see some difference in shading you may be able to get by with sanding the spots to the bare wood and then touching these up. If clear shellac doesn't bring the color back to the same as the rest of the floor, you could try using orange shellac or a mixture of orange and white shellac.

Q: In the area of the city where I live we have a problem with water in the basements following every heavy rain. Most of the basements have stone foundations, but none that I know of have sump pumps installed. I realize that these pumps will not get to the root of the problem and will only remove the water after it has entered, but it seems this would be better than bailing the water out with buckets. Do you know of any reason a sump pump should not be installed, or why none of these houses have them?

A: I can think of no reason why not - unless there is a serious problem of water disposal. In other words, a sump pump will pump the water out of the basement, but it has to empty somewhere. Some local ordinances forbid emptying the water into a regular sewer, or even into the street, so disposal can become a problem. The only solution in some cases is to dig a deep dry well or drainage pit at least 10 feet away from the foundation and lower than it - but even this can be a problem in areas where the soil itself is saturated and does not drain properly.

Q: There is a foul odor in one area near the outside of our house. I think there is a sewer vent in this location. It sticks up about 18 to 24 inches above the ground and is about 6 1/2 inches in diameter. It has holes about 1/2-inch in diameter in a 4-inch circle near the top. Could the smell be coming from this vent?

A: It is possible that this is a vent for your waste line, though I do not understand its location, unless you have a septic tank or cesspool installation. Either way, I would have a plumber check that waste line - it may be partially clogged, or the drainage system (if it's a cesspool or septic tank) may need cleaning or repair.