Q: The previous owner of my spinet piano painted it with a water-base paint. I now want to strip this off. Some comes off easily, but the rest requires paint and varnish remover, which then leaves the wood underneath dull. What is the best method to end up with a glossy finish?

A: As far as removing the finish is concerned, you are on the right track.

You will have to use paint and varnish remover -- preferably a semi-paste type. This will remove everything down to the bare wood if you use it properly (put it on thickly and give it time to work). Then sand the wood smoothy, dust with a tack cloth, and apply a new stain in the color of your choice, unless you like the color of the wood as it is stripped. After the stain is applied, apply three or four thin coats of high-gloss furniture varnish, following the directions on the can, and sanding with very fine paper between coats. Dust carefully after each sanding.

Q: Our bathroom ceiling is covered with mildew. We have painted it twice but the mildew comes back through the paint in a short while. The bathroom is heated and has a window in it. Can you tell us how to get rid of the mildew, and what kind of paint we should use when repainting?

A: Special mildewcide sprays can help you get rid of the mildew, or you can wash the walls with a solution of one part fresh liquid laundry bleach and three parts water. Add some powdered detergent, then scrub the walls clean and allow this solution to dry on the surface. Rinse off with plenty of clean water.

When you repaint -- soon after this washing and drying -- use mildew-resistant paint, or buy separate mildewcide additive for the paint you buy. Be sure a window is left open when the shower or bathtub is in use or, better yet, install an electric exhaust fan to the outside and make sure it is turned on when the bathroom is in use.

Q: Our son has a large mirror and two decorative medallions hung on an outside wall in his dining room. In cold weather there is moisture on the back of these, as well as on the wall directly behind them. The house has exterior walls of brick. How can we eliminate this problem?

A: Outside walls are always colder than the rest of the room, and I suspect that your house has very little insulation in these walls, so they are even colder than normal. The wall is warmed on its inner surface by the heat in the room, but air does not circulate behind the mirror and the medallions, so these areas remain colder than the rest of the wall. As a result, the moisture from the warm air inside the room condenses and collects there. Using spacers or other means to allow the air to circulate behind these objects should solve the problem.

Q: The sump pump in our basement works fine, but I worry about what will happen when there is a power failure at the same time there is a storm. Is there an auxiliary pump that will take over in such an emergency?

A: Yes. Several companies make battery-operated pumps that can be mounted directly over your existing pump. These have rechargeable standby batteries that are always ready. If water rises beyond the height of the regular pump, the battery-powered one will kick in and take over.

Q: My house is made of concrete block with stucco on the outside. This year we have cut back on our heat a great deal, and for the first time we are having quite a problem with condensation. The walls in the corners farthest from the heat sweat, and mold begins to appear in round spots. We have had this house for 30 years, and this is the first year we have had this problem. Is there a solution?

A: The key to your problem lies in your having lowered the heat, but not the humidity, inside the house. Block construction tends to be damp in many cases, and in your situation this probably contributes to the problem. Since the mildew thrives only in corners away from the heat, a fan or other means of circulating the warmer air would help. Additional venting, such as an exhaust fan, is needed in kitchen and bathroom.

Make sure these exhaust fans are in use when cooking or bathing occurs, and do everything else possible to lower indoor humidity. Wash the mold off with 1 part fresh liquid laundry bleach mixed with 3 parts water.

Q: Our house has a tankless hot-water heater that is part of the oil-fired furnace. To save fuel in the summer when the heating system is not in use, I plan to install a separate gas-fired hot-water tank and put it in a series with the tankless heater from the furnace. In the summer the furnace will be turned off and water will be heated by the furnace as it was before, with the hot-water tank serving merely as a storage tank for the hot water. Do you forsee any difficulties with this system?

A: In the winter the water in the tank will enter hot, but since hot water is made only on demand there will be nothing to keep the water in the tank hot if it has to stand unused for hours. The water in the tank will get cold and you will have to run water in a shower or sink until the full capacity of the tank is used up before you get any hot water. Meanwhile, all the fuel used originally to heat the water that went into that storage tank would be wasted.

Q: In an effort to conserve fuel oil, we have been turning off the emergency switch on our oil burner for all but about two to four hours each day. We are careful not to turn the switch off while the burner is running, but people have told us that this practice might damage the burner. Is this true?

A: As long as you don't turn it off while it is running, no damage will be done to the burner. Even if power were shut off while it is running, no serious harm would result, other than perhaps fouling of the nozzle and possible smoking when the burner comes back on.

Q: Is there any paint that will adhere to old ceramic tile in a shower enclosure?

A: A two-part epoxy will stand up best. You mix the two parts together before you start. However, you must do a very thorough job of cleaning and preparing the surface of the tiles, and especially cleaning old soap and dirt from the grout, before the paint is applied. Follow the manufacturer's directions exactly.

Q: the wallpaper in my son's bedroom was put up by a professional paperhanger about a year ago. Several days after it was hung there was a crackling sound, the paper pulled away from the walls in some spots, and several seams opened. The paperhanger returned to make repairs and this seemed to take care of the problem -- until a few weeks ago. The crackling sound came again one day while the windows were opened, and an entire section of paper lifted off. Can you tell me what caused this and what I can do to eliminate the problem once and for all?

A: I can't say for sure what caused the problem, but it could have been poor preparation of the wall surface underneath, use of the wrong kind of paste, mixing or applying the paste improperly, or a combination of all these factors. At any rate, I think the only solution now is to take all the paper off and clean the wall underneath thoroughly with a hot detergent solution. Next, sand off any gloss that remains on the wall and apply a coat of alkyd primer sealer to seal out whatever it is on the wall that may be interfering. Then hang the new wall covering in the usual manner. t