Torch-down roofing is a type of flat roof covering made from modified bitumen, which is applied using a torch to melt and adhere the material to the roof surface. Over time, rusting can become an issue, especially around metal flashings, fasteners, or vents embedded in or near the roofing system. Rust forms when moisture contacts exposed or damaged metal parts, which eventually leads to corrosion. This can cause leaks or weaken the overall roofing structure. Rust on torch-down roofs is commonly due to poor installation, inadequate sealing, or aging metal components that have lost their protective coatings. Simple diagnostics include visual inspection for orange or brown discoloration near metal flashings, and feeling for areas where the metal feels rough or flaky. Inside the attic or ceiling, signs of water stains or rust-colored streaks can further confirm the problem.
If you suspect rust issues, a safe DIY check involves examining flashings and seams closely to ensure they are fully sealed and intact. You can also gently clean the rust spots to see if they are superficial, but avoid using harsh chemicals that might damage the roofing material. If rust is severe or spreading, it’s wise to call a professional roofer who can assess whether metal components need replacing or if rust has compromised the roof’s waterproofing layer. When consulting a contractor, ask questions like, “How will you address rusted flashings or fasteners without compromising the torch-down membrane?” and “Do you recommend any specific coatings or treatments to prevent rust recurrence?” This ensures the repair respects the roof’s warranty and maintains long-term durability.