Q. I was told by a plumber and a contractor that I have a rotten sill in my cellar that must be replaced as soon as possible. My Cape Cod house was built in 1950. I haven’t a clue as to what this is and why it happened. I need your help. - MARIE
A. The plumber and the contractor were no help to you because they failed to tell you what exactly happened and failed to offer help, except to frighten you. The sill is the wood beam that sits on the top of the concrete foundation, and the rest of the house sits on that beam, called a sill plate. Parts of it rotted because the basement was closed up tight for 63 years, and water vapor came up through the concrete floor and condensed on the cool wood. Eventually, and especially on the Cape, this water caused the decay.
For starters, open basement windows for cross-ventilation, which will stop the condensation. Keep them open all year long. The two persons also told you to have the sills replaced as soon as possible, which is fairly important because with rotten sills, a house can drop a little, with possible damage to plumbing, floors, walls, and electrical wires.
I discovered rotten sills in my 1768 house in 1974, and promptly dug out the decay and put in new sills, laminating 2 x 8s in several spots. And long before that I ventilated the basement, adding two permanent vents. No more moisture and no more decay.
Replacing sills is tricky and hazardous. My friend, a contractor, was crushed to death when a house he was working on (to replace sills) fell on him. Contact a contractor and hire him to replace those sills with pressure-treated wood. It’s expensive, so get two or three bids.
Q. I put a glass tile backsplash in myself; the tiles are 1-inch square. There is a gap of approximately 1/4 to 1/2 inch between the top of the tile and the cabinets. What do you suggest for the gap? I don’t have a tile cutter, and the space isn’t uniform. My husband wants to put in a wood strip painted the same as the cabinets. I tried caulking and it looks horrid. - ELISSA DONNELLY, BY E-MAIL
A. Since the space is not uniform, cut a piece of wood the thickness of the tiles and to fit the uneven width. Glue it with an adhesive caulk. Buy a piece of trim (a shoe mold will do nicely) to cover the filled-in area, glue it in and paint or varnish it. A shoe mold is a quarter-round oak floor trim. Or buy ceramic trim strips, 6 inches long and about 3/4 inch wide, with one edge curved, in various colors. Install this with thin-set mortar.
Q. My bathroom exhaust fan duct goes through the ceiling, then turns horizontal along the attic floor to a vent in the attic wall. In winter, water vapor condenses into water that fills the bottom of the flexible duct, and freezes. When it melts, the water runs back into the ceiling fan and bathroom. How can I prevent that? - FIX-IT?
A. Raise the duct 6 inches, so any water that condenses will stay in the duct. There probably is not enough water or melted ice to make its way back to the fan, unless the vent on the attic wall is too high; in which case it can be lowered. Also, insulate the duct with duct insulation.
Q. I have to attach a steel TV bracket to an indoor brick wall with special “Blue” fasteners. Should I drill the holes in the mortar or into the brick? - CHICAGO
A. Drill into the brick, not the mortar. Try using an ordinary bit; if it doesn’t work you will have to use an impact drill.
Q. I converted my hot air system from oil to gas. Now the fan is very noisy, a lot noisier than the previous one. Can it be made quieter? - PETER UMILE, WEYMOUTH
A. If just the burner was replaced, the burning gas is much quieter than an oil-fired flame, so the fan appears louder than before. I don’t think much can be done about it, and you might be able to get used to it. On the other hand, if the entire system — furnace, burner, and fan — was replaced, the fan might have been installed improperly, so contact the installer to see if he can correct the error or install dampers on all contact points. There should be a good control of sound because a hot air system can telegraph the noise all over the house, via the ducts.Peter Hotton is also in the Thursday Styles g Section. He is available 1 to 6 p.m. Tuesdays to answer questions; call 617-929-2930. Hotton chats online 2 to 3 p.m. Thursdays, at Boston.com. Hotton can be reached at firstname.lastname@example.org.