Air leaks in house draw odors from basement
Q. We recently purchased a new home, which is about 7 years old. An odor from the basement seems to be drawn upstairs to the main floor, so I am putting towels at the base of the door to block the smell.
The basement is unfinished with high ceilings. There is another entrance coming from the garage at the other end. It seems as though some kind of chimney effect is happening here. I'm wondering if this is something we can rectify.
A. You are correct; there is a chimney effect, known as the “stack effect.” It means that there is exfiltration (air moving out) from the main floor or floors of the house through poorly weatherstripped windows, any attic access, a ceiling fan in the bathroom or other cracks in the envelope. The warm air escaping needs to be made up by sucking in air (infiltration) through poorly weatherstripped windows or doors in the basement, or the absence of a sill sealer between the masonry foundation and the mud sill (the pressure-treated plate that is bolted to the masonry).
You could try weatherstripping the door from the basement to the first floor. But the best approach for you would be an energy audit, which would point out all of the weaknesses in the envelope, so repairs can be done accurately. If you decide to proceed with such an audit (infrared thermography and blow door test), I can provide the name of the person I regularly work with on these problems.
Q. Four years ago, we had a room added on to our home, which it is 14-by-16 feet, built on 10-by-10 foot poles with 4-foot-deep footings. We expected some settling with some minor cracks, but the problem we are having is a constant cracking where the new wall meets the house, mostly near the cathedral ceiling. I have tried repairing a couple of times, but it still shows cracks. What can you suggest to fill in the cracks with?
A. You haven't told me how big the cracks are. If they are quite small, they may be recurring because the wood posts shrink and swell seasonally, whereas a masonry foundation (assumed for the main house) does not to the same extent. Such cracks will continue to appear, and the best solution may be to install a wood molding at the joint of the two structures.
But if the cracks are significant, you should consider having a structural engineer check the conditions surrounding the settling. Repeated sizable cracking despite repairs may mean that settling is continuing. If this is the case, it is a situation that needs to be stabilized, or any attempt at repairing the cracks is bound to fail.
Q. I have a stainless-steel, under-mount kitchen sink with a granite countertop. The original seal between the granite and sink has failed. We experienced mold buildup at the seal and water leaking to the cabinet below. We made two attempts to reseal it. First using Lexel, and a second attempt using another clear sealant. Before applying the new sealants, we removed as much old sealant without the removal of the sink from the granite countertop. Our results were no better than when we started. Is the sink removal the only way to seal it, and what product offers a tenacious bond, elastic seal and is mold-free?
A. The under-counter sink was probably sealed to the granite top with silicone, a popular and overrated caulking compound noted for many failures. Nothing else will adhere to silicone. Your only solution is to remove the sink and all remnants of the caulking with either Lift Off or McKanica Silicone Caulk Remover Gel, available at Ace Hardware stores. Follow the directions on the tubes, as they require a considerable time to work properly. Then use Lexel again.
Q. I am interested in your reply to a water problem regarding a flooded basement. The question was about installing ceramic tiles, etc. Our problem is somewhat similar. After a heavy rain, we have standing water in some areas of the yard for two or three days. In the back area, we do get a runoff from our neighbor, and other areas of the yard also have standing water. During a heavy rain, our two sump pumps are running constantly and doing a good job; however, we still get water overflowing the sump pumps' basin and covering the entire area of the basement with one to two inches of water.
Our village reviewed our problem and dismissed it without a satisfactory solution or recommendation. Discounting grade deficiencies, how would you suggest we pursue a solution to this problem? Do you have recommendation for companies that deal with this problem?
A. Grade deficiencies should be the first thing to look at. If there is any way for the water standing in your yard, including the water coming from your neighbor's, to be directed toward a low area farther away from the house, consider that. If not, water pooling away from the house foundation is not bad in itself, except that, in your case, it adds to the saturation of the soil, which seems to contribute to the excess water in your basement.
You haven't said what type of sump pumps you have or what their capacity is. Perhaps you should look into getting submersible pumps with a higher flow rate. Changing to a pump with a flow rate of 67 gallons per minute and a two-inch discharge pipe, you may only need one pump. Zoeller models 151, 152 or 153 would serve the purpose well; look for a dealer in your area by searching www.zoellerpumps.com.
Q. I'm looking to replace our 50-year-old, corrugated-metal roof with a new metal standing-seam roof on our cabin in southern Vermont. It has a roughly 30-percent slope with a cathedral ceiling. What thickness, warranty, brand, etc., would you recommend? I would also like to add four inches of new foam sheet insulation under the metal. What type of insulation would you recommend? We've had carpenter-ant problems in the past and would like to avoid issues with them digging in the insulation. Do you recommend taping the insulation panels? Are the insulation panels usually strapped down or just longer nailed along with the metal roofing? What type of underlayment do you recommend? The roof currently uses tar paper. Also, do you recommend space be added between the metal and the insulation to create ventilation (i.e., a cold roof) or to have the metal attached directly to the insulation?
A. Your corrugated-metal roof has served you well. When it comes to standing-seam roofing, I always recommend 24-gauge and double-lock seams. Single-lock-seam, 26-gauge roofs are not high quality and have a tendency to “oil can” and flutter in strong winds an unpleasant sound similar to one made when sheet metal is shaken. Insist also on the bottom of the standing seams being caulked and wrapped with a tab made when its drip edge is turned and locked onto the previously installed off-the-shelf drip edge. Failure to do that led to all the fascia boards rotting in a case I have been involved in recently.
The paint finish on factory-painted steel is generally under warranty, but the number of years varies according to the manufacturer. Some pre-manufactured panels offer a warranty on the panels themselves if the specified underlayment is used, with 20 years being the longest, and as long as certain criteria are followed.
The rigid insulation you are proposing to use can either be extruded polystyrene (XPS blue, gray, pink or green, but not white) or polyisocyanurate (polyiso, for short). Because you are planning to use four inches of rigid foam, stagger the joints of two 2-inch-thick layers. There is no need to tape the joints if you do that. The insulated panels need only be lightly held in place until either the sheathing or the sleepers are applied. There should be an air space between the insulation and the metal. This will require the installation of sleepers screwed through the insulation into the rafters below, and new sheathing over which to install the required underlayment and the metal roof.
Carpenter ants are looking for moist wood in which to build nests, so if the construction is done to prevent moisture problems, the risk of an infestation is minimized. Polyiso may be less susceptible to such an infestation, but I have no proof of this. You are planning on an expensive roof far more than replacing it with corrugated aluminum or pre-finished galvanized metal. If the cabin is strictly a seasonal residence, and only used sporadically in winter, is it worth spending that much on the roof when the walls, floors, doors and windows may be far less energy efficient?
Q. I live in a two-story condo in New Jersey. I live on the second floor with an attic, and I've been plagued by silverfish for years. I had an exterminator treat the attic; he sprayed several times a year. I saw one or two bugs occasionally, but now I see a few very large and dark in color on a daily basis. I have used different powders and sprays, but I can't get rid of them. Can you help me?
A. Silverfish and their cousins firebrats are light-colored. Very large, dark insects may be cockroaches. Try to catch one or more samples of the critters and take them to an exterminator, or have him or her come again to treat your premises. Meanwhile, try placing a couple of small dishes or empty, and clean, small cans (like tuna fish or cat food) with a couple tablespoons of 20 Mule Team Borax powder, topped with a pinch of sugar. Place them where you have seen the critters. A reader gave me this tip years ago; her grandmother told her about it and it works.
Ÿ Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.
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