Built-up roofing (BUR) systems consist of multiple layers of bitumen and reinforcing fabrics, creating a durable, weather-resistant surface often found on flat or low-slope roofs. Proper ventilation is crucial for BUR roofs to prevent heat buildup and moisture accumulation, both of which can shorten the roof's lifespan and lead to problems like blistering, warping, or leaks. Ventilation helps regulate temperature and moisture levels in the attic or roof deck, reducing the risk of trapped heat that can soften the asphalt layers or cause insulation to lose effectiveness. A good ventilation strategy typically includes a balance of intake and exhaust vents to allow fresh air to enter and hot, moist air to escape, keeping the roof system stable and extending its longevity.
You can do some simple checks yourself by inspecting your attic or roof space for signs of moisture, such as mold, damp insulation, or a musty smell, especially after rain or snow melts. Also, look for any visible warping or bubbling on the roof surface as these can hint at inadequate ventilation. However, because BUR roofs are complex and layered, it’s wise to call a roofing professional if you suspect a ventilation issue. When you consult a contractor, ask specific questions like: “How does your proposed ventilation plan balance intake and exhaust to reduce moisture and heat?” and “Can you explain how your solution aligns with the roof’s manufacturer warranty requirements?” These questions help ensure your ventilation strategy supports the built-up system without voiding warranties or causing damage.