Built-up roofing, or BUR, is made of multiple layers of bitumen and reinforcing fabrics, often topped with gravel for protection. Over time, thermal movement—caused by the expansion and contraction of roofing materials due to temperature changes—can put stress on these layers. This happens because materials expand when heated and shrink when cooled, which might lead to cracks, blisters, or splits in the roofing layers. These issues often start small and can be spotted by looking for bubbling surfaces, cracking seams, or gravel displacement. Homeowners can safely check for obvious signs like loose gravel, visible cracks, or pooling water on the roof, but always avoid walking extensively on BUR without proper footwear, as this can damage the gravel layer or underlying membranes.
If you notice any of these signs, it’s a good idea to call a professional roofer. A roofer will conduct a detailed inspection, checking for internal moisture and structural damage that might not be visible from the outside. When hiring a contractor, ask how they will account for thermal movement during repairs or replacements. Specifically, you might inquire, “How do you ensure the roofing system accommodates expansion and contraction to prevent future damage?” and “Will the repair method maintain my roof’s warranty, especially concerning thermal stress-related issues?” Since improper repairs or incompatible materials can void warranties, working with an experienced roofer who understands BUR systems and thermal movement is key to a long-lasting roof.