Attic ventilation is the part of a roof most homeowners in Coeur d'Alene never think about, and it is behind a big share of the ice dams, attic frost and early shingle wear we see.
A vented attic needs air coming in low and going out high. Intake comes through soffit vents at the eaves. Exhaust leaves through a ridge vent, box vents or gable vents. The International Residential Code sets a minimum net free vent area based on attic floor area, and it works best when intake and exhaust are close to balanced.
What we find is soffit vents painted shut or buried under blown-in insulation, no baffles to keep insulation off the eave, a ridge vent on a roof with no intake at all, or two kinds of exhaust fighting each other. Bathroom fans venting into the attic instead of outside are common too, and in a North Idaho winter that moisture turns into frost on the underside of the roof deck, then drips when it warms up.
Our fix depends on the house. It may be cutting in continuous soffit vent, installing baffles, adding or converting to ridge vent, and running bath fans out through a proper roof jack. We also point out air leaks around can lights and the attic hatch.
Better ventilation keeps the deck cold in winter and cooler in summer. That means fewer ice dams and shingles that wear out slower. Pair it with ice dam prevention.
