Wall insulation. Adding insulation to exterior walls alters the air exchange characteristics and can establish a dew point within the wall cavity. Moisture (vapor) then condenses (turns back to liquid) on the inside face of the exterior wall causing mold, mildew, wood decay, and exterior paint failure. Prevent these problems by using an effective vapor barrier at walls and ceilings and reducing humidity (unvented clothes dryer = 5 pints of water / load).

Ice dams. These are created by improperly installed attic insulation and poor attic ventilation. Hold the insulation back from the underside of the roof at the overhangs (or install baffles). This allows outside air that enters through the soffit vents to pick moisture laden attic air and carry it out through the gable, ridge, or roof vents. And equally important - go on a moisture hunt and reduce indoor humidity levels (5 min shower = .5 pint of water).

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