Polyurethane roof coatings are popular for protecting flat or low-slope roofs because they create a seamless waterproof barrier. However, the fasteners holding the roofing materials in place can sometimes back out, meaning they loosen or rise from their original position. This issue often happens because of temperature changes causing expansion and contraction of the roof deck and systems, improper installation torque, or when the substrate beneath the fasteners deteriorates over time. A simple way to check for fastener back-out is to visually inspect the roof for any raised or loose fastener heads and look for small wrinkles or bubbles in the coating near the fasteners, which can indicate movement beneath the surface. It's important to do this check safely, using stable footing and a harness if needed, especially on sloped surfaces.
If you notice fasteners backing out, it’s best to address the problem quickly to avoid leaks or coating damage. Small DIY fixes include gently pressing down fastener heads and applying touch-up polyurethane coating afterward to reseal the area. However, do not over-tighten fasteners yourself, as this can cause more damage or void warranties. If loose fasteners are widespread or if the roof deck seems compromised, it’s time to call a professional roofer. When discussing the issue with a contractor, ask if they use fasteners compatible with your roof system and substrate, and whether they will conduct a thorough inspection to identify underlying causes, such as substrate movement. Also, inquire about how repairs will be done to maintain your coating warranty, ensuring the fix is both effective and lasting.