Fascia, Soffit, and Gutters
Attic ventilation requires both intake and exhaust. Soffit vents provide the intake air that flows up through the attic, collecting heat and moisture, and exits through ridge vents or gable vents. Without adequate soffit intake, ridge vents can't work effectively.
Inadequate attic ventilation causes two primary problems: in summer, trapped heat elevates attic temperatures, increasing cooling loads and accelerating shingle deterioration; in winter, warm moist air from living spaces infiltrates the attic, condenses on cold surfaces, and creates moisture damage and mold.
Protecting Your Home's Exterior
Ice dam formation is strongly linked to inadequate attic ventilation. A warm attic melts snow at the peak, which refreezes at the cold eaves, building the ice dam that causes roof leaks. Adequate ventilation keeps the roof deck uniformly cold.
Soffit vents get blocked by insulation. During attic insulation installation or settling, insulation can migrate toward the eaves and block soffit vent openings. Baffles (rafter vents) maintain the air channel from soffit to ridge.
Professional Installation
Blocked soffit vents can be identified from outside: damaged, painted-over, or caulked-shut vent openings are visible on close inspection. From inside, an insulation blanket against the eave framing suggests venting is compromised.
Ventilation calculations follow standard ratios: one square foot of vent area per 150 square feet of attic floor (or 1:300 with vapour barrier), split roughly evenly between intake (soffit) and exhaust (ridge).
When replacing soffit material, ensure the new soffit includes adequate perforated or vented area. Solid soffit panels without vent openings eliminate intake ventilation entirely — a common and costly mistake in renovation projects.