Dealing with Dry RotQuestion: What can be done about apparent dry rot damage to basement beams and joists?
Answer: Dry rot is a term for decay that occurs when no decay mechanisms are apparent. It is still decay and requires moisture to occur. According to scientists at Forest Products Laboratory in Madison, wood needs at least a 25 percent moisture content for decay to occur. You must find a way to reduce moisture to stop the decay. In the basement, this means stopping leaks and possibly running a dehumidifier.
You should check the beams to see how far the decay has progressed by probing them with an ice pick or screw driver. If the instrument penetrates, consult an engineer or housing inspector to determine what needs to be done.
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Drying out a Crawl SpaceQuestion: What can be done to dry out a crawl space when open windows aren't drying it out?
Answer: Open windows or vents don't usually provide enough ventilation to warm a crawl space adequately to prevent condensation. They introduce warm air which is cooled by the cooler walls and ground to the point where moisture condenses on the coolest surfaces. The best solution is to close the windows and otherwise stop air from leaking into the crawl space. To be sure that moisture is not evaporating from the soil cover the soil with heavy plastic. Overlap the plastic and weight it down at the joints and around the edges.
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Proper Humidity Levels in the HouseQuestion: What is the recommended indoor relative humidity for homes is Wisconsin?
Answer: In most homes, relative humidity should remain between 30 and 40 percent during the winter. Higher relative humidities are likely to cause condensation problems on windows and outside walls. Lower relative humidities may be uncomfortable and cause static electricity.
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Moisture ProblemsQuestion: What would cause wet spots on ceilings during the winter?
Answer: There area two probable causes - ice dams or condensation. Water coming from ice dams or other roof leaks will stain the ceiling before you notice evidence of moisture on the ceiling surface. Moisture on the surface without the accompanying stains probably is condensation resulting from a cold spot on the ceiling. If this occurs in isolated spots, check the attic. You may find the insulation missing or bunched up so that it isn't doing its job in the affected area.
Question: Why would a house have condensation problems after a new furnace is installed?
Answer: Your humidity problem does not mean that your furnace is defective. The old furnace drew air from inside the house to support combustion. It also sent a stream of air up the chimney and out of the house when it operated. Therefore, in addition to providing heat it also provided ventilation for the house. Your new furnace doesn't provide this ventilation. It appears you need to find a way to replace the ventilation system you lost. You can do this by running a kitchen range hood or bathroom exhaust fan several hours each day until the condensation problem vanishes. Open a window on the other end of the house an inch or so to provide replacement air. Adding more fresh air is more effective than a dehumidifier. A dehumidifier will typically only lower humidity to about 50%. Winter condensation problems usually require that humidity levels be kept below 40%. Bringing a controlled amount of additional fresh air into your house should also be cheaper than running a dehumidifier.
back to topUsed by permission of John Merrill and the University of Wisconsin Cooperative Extension
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