A Built-Up Roof (BUR) is a traditional roofing system composed of multiple layers of bitumen and reinforcing fabrics, finished with a top layer of aggregate or smooth cap sheet. It’s designed to provide a durable, waterproof surface, often used on low-slope or flat roofs. Ice and water shield is a self-adhering membrane primarily used as an underlayment to protect vulnerable areas like eaves, valleys, and around roof penetrations from water infiltration caused by ice dams or wind-driven rain. Even though BUR systems are tough, winter conditions can lead to ice dams where melting snow refreezes at the roof edge, causing water to back up under the roofing layers. Installing ice and water shield in these trouble spots adds an extra layer of waterproofing, reducing the risk of leaks and damage to the roof deck beneath the BUR.
You can do some simple checks yourself to see if ice and water shield is or should be in use. Look for any signs of water stains, damp spots, or mold on your ceiling after a freeze-thaw cycle; these can indicate where water has bypassed the main roofing layers. Inspect valleys, eaves, and around vents for any damaged flashing or shingles that could let water seep in. If you’re considering adding or replacing ice and water shield, calling a qualified roofer is recommended as proper installation requires skill to avoid trapping moisture or causing blistering beneath the BUR layers. When you speak with your contractor, ask if they follow manufacturer guidelines for applying ice and water shield on BUR systems to maintain warranty coverage, and whether they use self-adhering membranes rated for the specific climate your home is in. This approach helps ensure your roof remains leak-resistant and covered in case issues arise later.