Severe Dampness

Living in the beautiful Pacific Northwest, we tend to have higher moisture and dampness in our homes. Being a home inspector from the greater Portland area, I’ll share with you some findings.

Some homes have problems with excessive moisture. It’s most noticeable as condensation on windows. If moisture is excessive and stays on your windows for several days… if water runs off windows and damages wood surfaces…if ice forms on windows and frames…or if storm windows remained fogged up and icy all winter, you need to reduce the humidity level inside your home.

Condensation requires a cool surface and moisture in the air. Inside your home, when the temperature of the glass drops below the dew point of the inside air, invisible water vapor in the air condenses as water on the cool glass. More condensation occurs when there is more water vapor in the air and/or when glass surfaces become colder.

Evaluate changes you have made to your home—any effort to tighten up a home and reduce air infiltration will increase humidity levels. A high-efficiency furnace vented with two plastic pipes draws combustion air from outside and reduces ventilation. Weatherstripping, better windows, caulking, and any other measures you have taken to reduce air leaks will increase the amount of moisture retained inside your home.

Try to increase ventilation by running kitchen and bath exhaust fans whenever steam is produced by cooking or bathing/showering. In the bathroom, keep the fan running until the bathroom is dry. Add timer switches to the fans if necessary.

Limit the number of plants in your home. Look for plumbing leaks or damp areas in the basement. If basement crawl spaces have bare soil, cover the soil with a vapor barrier.

There are many other sources of moisture and ways to eliminate excess moisture. Often your local natural gas utility company can provide information on moisture problems. University extensions often have good booklets on solving moisture problems.