When sizing and placing intake and exhaust vents for synthetic shake roofing, the goal is to create a balanced ventilation system that promotes proper airflow underneath the roof deck. Intake vents, typically installed near the eaves or soffits, bring fresh air into the attic space, while exhaust vents near the ridge or upper roof surfaces allow hot, moist air to escape. For synthetic shake, it's important to follow the general guideline of providing 1 square foot of net free ventilation area (NFVA) for every 300 square feet of attic floor space when a balanced system is used. The vents should be evenly distributed and unobstructed, ensuring air flows freely from the intake to the exhaust. Synthetic shake can retain heat, so adequate ventilation helps prevent warping, early aging, and moisture buildup, which can void manufacturer warranties.
A simple DIY check for adequate ventilation is to look for signs of moisture or heat damage in the attic, such as mold, mildew, or warped wood, especially after winter or humid periods. Homeowners can also visually confirm that soffit vents aren’t blocked by insulation and that ridge vents are visible and clear of debris. If you’re unsure about whether your vent sizing and placement are correct, it’s wise to contact a professional roofing contractor. When consulting a roofer, ask, “How does your ventilation plan comply with the manufacturer's recommendations for synthetic shake?” and “Can you verify the net free ventilation area provided by the vent products you propose?” These questions help ensure your system is code-compliant and preserves your roof’s warranty.