Q: We live in a 70-year-old Cape Cod-style house. The rooms on the second floor have sloping sides and a portion of the ceiling is flat, so there is a space above this, between the narrow ceiling and the peak. There is no access to the space under the peak, and no sign of vents for that space. We have been told that there is probably insulation directly under the roof and we should therefore not vent that space unless we put insulation down on the ceiling. To do so, we would have to cut an access door on the ceiling. Also, the second-floor rooms get very hot in the summer. What do you suggest?

A: I suggest cutting that access door so you can find out what is really doing up there. If insulation is up to the peak, I would put it down onto the top of the ceiling instead, and I would add vents to the space at each end. This will not only help prevent condensation problems (which you may have), it will also help disperse trapped heat in the summer.

Q: We have two brick floors that looked beautiful until white spots that look like lime started to appear in various places. What can be done to dissolve and remove these spots?

A: This is efflorescence, which is caused by dampness leaching alkaline salts out of the brick. You can wash it away with a mild solution of muriatic acid (sold in most paint and hardware stores), but there is no guarantee that it won't come back. It will neutralize the alkali for a while, but if moisture is still present, the condition may return. Application of a clear masonry sealer sometimes helps, but it will darken the floor.

Q: I have a round cherry wood table on which I used a solution of turpentine mixed with linseed oil that was supposed to help preserve the wood, but now the top of the table looks awful. I have always used a good-quality felt pad on the table, so I don't think it is from that. Can you tell me how I can clean this table top?

A: Linseed oil is an organic oil that never really dries completely, making it a poor choice for use as a furniture polish. Putting a felt pad on top would only make matters worse, as the oil soaks into the felt and as dirt tends to stick to both (due to the stickiness of the oil).

I advise you to clean all this off by rubbing with a clean cloth dipped into paint thinner. Keep turning the cloth so you don't just spread the dirt and dissolved oil around, and replace the cloth with a clean one when the first one starts to look dirty. Remember that paint thinner is highly flammable; room and make sure there are no open flames or lit cigarettes in the room with you. When the wood is clean, apply a good grade of furniture polish or wax.

Q: We recently bought a house with wood floors that are in very good condition and we want to maintain them that way. Should we just continue to wax them frequently, or should we strip the wax off and apply polyurethane varnish on the floors?

A: If the floors are in good shape, I see no reason to even consider stripping them. Just keep them clean by frequent vacuuming or dusting, and buff as often as possible. Apply wax as needed, but not too frequently; too much wax does more harm than good. Apply more wax only when you cannot get a luster after buffing -- in other words, when the wax appears to be worn off.