PVC roofing is a type of single-ply membrane widely used for its durability, chemical resistance, and heat-reflective properties. However, one common issue that can occur over time is blistering. Blistering happens when moisture or air gets trapped beneath the PVC membrane, causing bubbles or raised areas on the surface. These blisters can form during installation if the membrane was not properly adhered, or they can develop later due to trapped moisture from leaks, poor drainage, or manufacturing defects. Diagnosing blistering usually involves looking for raised, air-filled bubbles or soft spots. You can carefully press on these areas—if they feel spongy or you notice trapped air, chances are you have blisters. It’s important to conduct these checks safely by using a ladder responsibly and not walking on the roof unless you are sure it can support your weight.
If blisters are still small and not leaking, you might perform some simple DIY tests like inspecting inside your attic for signs of water intrusion or mold, which indicate a more serious problem. However, PVC blistering often requires expert evaluation because improper repairs can invalidate manufacturer warranties. If you notice large blisters, ruptured membranes, or signs of water damage inside the home, it’s best to call a professional roofer experienced with PVC systems. When you do, ask them two key questions: “What caused the blistering in this PVC roof?” and “How will your repair method protect my roof warranty and prevent future blistering?” These questions help ensure the roofer will address the root cause and follow manufacturer guidelines, giving you peace of mind and a longer-lasting roof.