Properly sizing and placing intake and exhaust vents is crucial for maintaining a healthy roof system with asphalt shingles. Ventilation helps regulate temperature and moisture in the attic, preventing problems like shingle damage, ice dams, and mold growth. The general rule is to provide 1 square foot of ventilation (both intake and exhaust combined) for every 150 square feet of attic floor space, but this may be adjusted to 1:300 ratio if a vapor barrier is installed. Intake vents are typically placed under eaves or soffits to allow fresh air to enter, while exhaust vents are near or at the ridge to let hot, moist air escape. If intake vents are blocked or too small, airflow will be restricted, leading to poor ventilation and potential roof issues. Simple checks include ensuring soffit vents are clear of insulation or debris and visually inspecting ridge vents for any damage or gaps that might hinder airflow.
Homeowners can safely inspect vent placement from the exterior during routine maintenance, looking for proper vent alignment and listening for airflow on windy days, but detailed airflow assessment is best left to professionals with specialized tools. If you notice signs like uneven shingle wear, attic condensation, or unusually high energy bills, it’s time to call a roofer experienced with ventilation. When consulting a contractor, ask how they determine the vent sizing based on your attic’s square footage and roofing system, and whether they will verify that intake vents are unobstructed by insulation during installation. Additionally, inquire if the ventilation plan complies with building codes and won’t interfere with your shingle warranty, ensuring a balanced and durable roofing environment.