Healthy Indoors Magazine - USA Edition

Healthy Indoors | 31 : I can't tell you how many times people have said to me, "My basement is pretty dry; it only gets damp during a heavy rain." There should be no water seepage into a basement or crawlspace. How can you avoid such problems? Be sure there are no cracks in your founda- tion walls. Check outside to be sure that the gutters and downspouts are operating as intended: that gutters are not clogged, resulting in splash on the ground next to the foundation; and that downspouts are directing roof water away from the foundation. Even one downspout that is dumping water next to the house can result in water intrusion in the basement. If you walk around the exterior of your home during a heavy rain, you can check to be sure that roof water isn't pouring down from your gutters rather than flowing into downspouts. If your downspouts are inserted into underground piping, be sure that the piping is receiving the downspout wa- ter. If not, you may have a drywell that has filled up over time. In that case, you can bury solid 4-inch PVC piping a few inches under the soil, extend the piping to daylight at the edge of a deep landscape furrow or downhill from the house, and insert the down- spouts into that piping. ust an "insect screen." Attach the ma- chine to a condensate pump so that it can drain into a sump or sink or to the exterior. Measure the H with one or two thermo-hygrometers, placed on or near the floor. Such devices can also be remote-read, which can be useful in a crawlspace.) If the H exceeds 50 percent, increase dehumidification. The RH in finished basements should be no higher than 0% . Poorly insulated finished basements can get moldy if the H is higher than 50% .) ou can dehumidify or air condition finished basement spaces in the hu- mid season you may need to add de- humidification if air conditioning is not sufficient. When you turn the heat on in your house for the fall/winter/early spring, you must also heat your fin- ished basement, whether you are us- ing it or not, with the temperature set at a minimum of 0 o F. As air cools, its relative humidity H) rises, which is why cold below-grade spaces can have high H condi- tions. Many types of mold including allergenic Aspergillus and enicillium species can flourish in the absence of liquid water if the relative humidity is over 0 percent, which it often is in cold corners below-grade. Wa hausting into the house or even into a crawlspace or basement, all that mois- ture and the lint will fuel mold growth. Se : Look under sinks and behind toilets to be sure that the pipes aren't leaking. Hidifiatin If you have a cen- tral humidification system or use a portable humidifier, use one or more thermo-hygrometers usually available at Home epot) to measure the rela- tive humidity H) in the house or the room that's being humidified. The RH should be no higher than 40 percent or even 30 percent in cold weather) . If moisture is condensing on cold surfac- es such as on or near windows, then the H may be too high. El : The H in crawlspaces and unfinished base- ments should be no higher than 50 percent. If you see condensation on cold surfaces such as a well-water tank or cold water pipes, the H is too high.) espite what the Building Code may dictate, crawlspaces should be isolated from the exterior no open vents and dehumidified in the humid season in New England generally between mid-April and mid-October) . se a dehumidifier adequate for the space and one that contains an effi- cient, pleated-media filter rather than A dryer was venting into this crawlspace, leading to lint buildup and mold growth on surfaces. oisture reecting the photo ash as condensing on the foundation walls, and the foundation and stored goods were moldy.

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