Several factors can raise humidity in a home

Q. Could you give some explanations as to why our house has high humidity? Most of the time it's around 65 to 70 percent. In the winter, we run two dehumidifiers. During the spring we shut them off and try to open the windows as often as possible. But as soon as we close the windows, it comes right back fast.A. There are several possibilities. If you have a crawl space or an old cellar, and its floor is not covered with concrete or plastic, moisture exuding from the soil may be responsible. The same is true if they are repeatedly wet when it rains or during snow melts. Other potential causes of excessive moisture: The size of the house, number of people and animals, long showers or hot baths, certain types of cooking without the use of fans, a large number of water-loving plants, storing firewood in the basement, drying laundry inside, an unvented dryer, bath or kitchen fans venting in the attic instead of outdoors, etc. Dehumidifiers are not very effective in the winter, as they work best when the temperature is uncomfortably hot. They are also expensive to run. Investigate your lifestyle and see if it is responsible for your excessive moisture levels.Q. What would you recommend as an alternative to recessed-light fixtures in our cathedral ceiling? I really do appreciate your advice on this matter. I have been living with this issue way too long.A. Your question follows an earlier answer, noting that recessed lights in cathedral ceilings are a potential source of moisture convection into the confined space, which can result in undetected condensation or leakage through the ceiling, both of which can result in severe structural damage. Recessed lights in ceilings below any attic space are undesirable for the same reason, albeit not as serious as in the case of cathedral ceilings. The best practice is to have surface-mounted lights or no lights at all.Q. I have a follow-up question on the wax seal on the toilet. Our basement is finished. Beginning about mid-January until warm weather arrives, we have a terrible odor in our basement bedroom and crawl space. The crawl space is off the bedroom. The odor is concentrated to the front corner of the crawl space and just opposite that wall on the bedroom side. The odor lessens the further back in the crawl space you go. If the bedroom door is left open, I can smell the odor upstairs. It is a septic-like smell. Last year, I had two plumbers come out and check the areas for any plumbing/pipe issues. They found nothing. I also had a pest-control company out to check for mice, dead animals, etc. - again, nothing. I have run a dehumidifier in the bedroom and crawl space without any unusual results. I am wondering if this could be coming from the toilet wax ring on the main floor of the house (we have a bathroom in the basement, on the main floor and two upstairs). Does this seem a likely cause for the odor if the odor is not in the bathroom itself?A. Stranger things have happened in houses, but it is doubtful that you would smell the odor downstairs from a toilet above, as the stack effect in the house would draw the smell upward during the winter months. However, it's worth investigating, considering that from your description there are few other options. If you have a floor drain near the bedroom, check the trap by putting water in it; if the smell stops, that is likely to be your problem. Otherwise, without investigating on site, I am stumped. Dead animals would not smell for an entire winter and should not recur every winter anyway.Q. We have a Tudor, and its two facades are made out of stucco and painted clapboard. My spouse thinks we would improve the house's appearance if we put stucco over the clapboards. Do we need to remove clapboards to put the stucco wall or can we put it over the existing clapboards? If we can, what should be an exterior-wall section?A. The clapboards should be removed so a mason can attach mesh to the sheathing. A mason experienced in the installation of stucco is the person to call. I am not sure what you mean by an "exterior-wall section."Q. A few weeks ago in your column you wrote about a product to clean kitchen cabinets. I cut out the column, but alas, it was recycled. Can you tell me its name? Do you have a product you recommend for cleaning hard-water residue from a fiberglass tub?A. The cleaner I mentioned is Milsek Furniture Polish. Many readers have used it and written to tell me what a miracle product it is. I hope you will be as happy with it. You can buy it at www.milsek.com or by calling (800) 216-9517. To remove the hard-water deposits, first try white vinegar. If that does not work, try Lime-A-Way, but be sure to follow directions carefully, as it does have the potential for damaging surfaces if not handled as recommended.