Address water problems such as seepage from the outside, leaks in a roof or walls, and leaky pipes. When Installing Insulation Excessive moisture in the home filters through insulation and causes it to become damp and matted and to lose much of its effectiveness. To be effective, such a material must have a high resistance to moisture flow. New Construction Choose wood or vinyl-sheathed wood rather than metal for windows and gliding doors. This will reduce the likelihood of condensation on the frame and sash.
Wood is a better insulator than metal.
Metal frames without thermal breaks conduct heat readily, so the inside surface of a metal window frame is cold in the winter. When humid air comes into contact with cold metal, condensation, and often freezing, occurs. Make sure the attic and crawl space are cross-ventilated. The crawl space should be covered with a vapor barrier. This will prevent water vapor from rising from the soil into your house.