Q: In every corner inside our house the walls get wet with condensation. We have washed these areas with bleach, then painted them with shellac and semigloss, but we still have the problem with sweating. We have put vents in the outside siding and have replaced the storm windows, but the sweating continues, including on the inside of the windows. We know there is some insulation in the walls. Can you help us with this problem?

A: Condensation (sweating) occurs only when warm moist air comes in contact with a colder surface-in your case, in the upper corner of the walls. It seems to me that those surfaces are cold because of a lack of adequate insulation. You say there is insulation. You say there is insulation in the walls as far as you know so it is likely that there is no insulation in the ceiling. This would explain why the problem occurs near the top of the walls (next to the ceiling), and on the ceiling; the ceiling gets cold and absorbs hear from the walls. Also, the wall insulation may not be enough to keep it warm. It is also likely that the relative humidity inside your house is too high, meaning that you must provide more ventilation in kitchens and baths, or use a dehumidifier.

Q: Our home has cedar shingles on the outside that hafe never been stained or oiled, just allowed to weather naturally. W are now thinking of applying linseed oil. Would this be beneficial-or is there something else we should apply?

A: I would not advise applying linseed oil. This oil tends to develop mildew, and darkens greatly with age in most cases. Cedar can be left to weather naturally, though it may tend to check or crack, and may get dirty looking. If you want to apply a clear sealer, use either a colorless cresosote, or one of the clear wood preservatives that all paint stores carry.