Exposed fastener metal on metal roofs refers to the screws or nails that directly connect panels or flashing and remain uncovered by caps or sealant. Over time, these metals can degrade when exposed to ultraviolet (UV) rays from the sun combined with weather elements. UV light breaks down protective coatings like paint or sealant around the fasteners, leading to rust and corrosion. This degradation happens because the fasteners are often made of galvanized or zinc-coated steel, which isn't as UV-resistant as the roofing panels themselves. To check for this issue safely, homeowners can inspect their roof on a clear, dry day, looking closely for rust discoloration, cracks in sealant around fasteners, or fasteners that feel loose. If you notice any signs of rust or holes forming around the screws, it’s a sign that the protective barrier has failed.
Addressing exposed fastener wear early is key to preventing leaks and further structural issues. For minor cases, replacing rusted fasteners with those coated in a UV-resistant material or stainless steel, and applying new sealant designed to withstand UV exposure, can extend roof life. However, if widespread corrosion or significant fastener failure is visible, it’s best to call a roofer to assess. When hiring a contractor, ask specifically whether they use UV-resistant fasteners and what type of sealant they recommend to maintain warranty compliance. Also, inquire about their process to inspect and replace fasteners without damaging the roofing panels. These questions will help ensure your metal roof remains protected and your investment secure.