Question: We have had a high-efficiency furnace for the last three years. All at once we have a very loud popping noise in the air ducts. Sometimes it does this when it is heating; sometimes it is when it is cooling. The main air duct that runs the full length of the basement is boxed in. The rest has a dropped ceiling. How would you suggest we go about remedying this problem? The popping never sounds like it is in the same place. - J.B., Fort Branch, Ind.
Answer: The popping is most likely caused by expansion of sheet metal attached to the bottom of the floor joists. Thin sheets of metal are used to box in the floor joist cavity to be used as a cold-air return. When the humidity level in the home changes, the wood joists expand and contract accordingly. The movement causes the metal to move and pop.
You may even notice the problem when you walk in certain areas, causing the floor joists to move.
Because this is a widely occurring problem and because working with metal is more difficult, heating contractors have turned to a rigid fiberglass panel in the place of sheet metal for both cold-air returns and for main ducts. Contact your heating contractor for supplies.
Question: I enjoyed your article on preparing homes for winter, but we cannot find the latex joint filler to use in concrete walks or porch floors that have cracked. Filling those cracks with concrete does not improve the situation. We talked to our hardware store, and the people there could not help us. - J.B., Oakland City, Ind.
Answer: Recently I was in a hardware store and found acrylic latex and butyl latex caulking in the paint department. Macklanburg Duncan's Mr. Macs product line includes a latex crack filler and a urethane joint filler to repair and restore concrete. You also can use any high-quality silicon caulk, such as Polyseamseal's new clear outdoor caulk.
Question: I don't understand one of the things you mentioned in your story on preparing the home for winter. I asked an electrician, and he did not know the answer. Could you please explain why a GFCI needs to be tripped and reset once a month and the other breakers every six months. - C.A.V., St. Anthony, Ind.
Answer: A GFCI (ground fault circuit interrupter) and standard circuit breakers are mechanical switches. Anything mechanical can fail without proper care and maintenance. In the case of an electric switch, the mechanism can become corroded, and the switch might not work when needed. Flipping the switch off and on keeps the contacts clean.
With a GFCI breaker or outlet, press the test button and then the reset button if the breaker or switch trips. If the GFCI switch does not trip when testing, it is defective and you need to have it replaced.
C. Dwight Barnett is certified master inspector with the American Society of Home Inspectors. Write to him with home improvement questions at C. Dwight Barnett, P.O. Box 14091, Evansville, IN 47728.