Q: Our 70-year-old house has cedar shingles on the roof that have been treated many times, presumably with creosote.Recent repairs have left us with some shingles that are lighter. What can you recommend as a treatment for the roof to make it look better and make the lighter shingles blend with the lighter ones?

A: The usual treatment for wood roof shingles is a stain that is formulated for this purpose (it's sold in paint stores and some lumber yards). This helps preserve them, as well as improve their appearance. A dark color will tend to neutralize differences in shading between old and new, though not entirely in most cases. It may help to apply a light coat on the new shingles alone, before doing the entire roof, to bring them closer in shade at the beginning.

Q: When our country house was built we had a number of doublepane fixed windows installed in the living room. These were not stock size and had to be ordered. Although they were fine at first, the windows developed condenstation leaks repeatedly, and I have now had them replaced three times. They last about six months to a year, then start leaking internally. The supplier will not replace them again. What can I do to clear the windows, and what can be done to prevent recurrence of the condensation between the panes?

A: A double-pane insulating window that is properly made and installed should not develop the kind of leaks you describe. The seals should be airtight almost indefinitely. Assuming there are no structural problems in the house that could be causing the glass seals to crack or develop leaks, there is obviously something wrong with the brand of window you have been buying. I would first try to contact the manufacturer of the glass (not the dealer who made or installed the windows) to see if you can get any satisfaction from him. If not, the only other suggestion I can make is to call in a different professional glass contractor and buy new insulating glass -- but this time get a reliable brand made by a large manufacturer who factoryseals the edges of the panes so leaks cannot develop.

Q: We have ordered new floor tiles for our kitchen and the dealer wants to install the new ones on top of the old ones. These old tiles are badly cracked and a number of them are loose, so we don't think they will make a good foundation for the new tiles. Another layer of tiles would also raise the floor higher than the adjoining dining room floor. Should we insist that the old tiles be removed first?

A: From your description I would say that removing the old tiles is a good idea, but don't expect to have the job done for the price originally quoted. Removing the old tiles can be time-consuming, and therefore expensive, and will substantially increase the total cost of the installation.