EPDM (ethylene propylene diene monomer) roofing is a popular single-ply membrane known for its durability and flexibility, often used on flat or low-slope roofs. Chimney flashing is the metal material that seals the gap between the chimney and roof to prevent water penetration. Leaks around EPDM and chimney flashing tend to happen because the flashing can pull away from the membrane, get damaged, or the sealant can deteriorate over time. This can allow water to seep beneath the membrane or into gaps around the chimney, causing leaks inside the home. This problem often arises due to poor installation, shifting of the building structure, or weather wear, such as UV exposure or freezing/thawing cycles stressing the materials. You can start by carefully inspecting the area where the chimney meets the EPDM membrane for obvious cracks, tears, or missing sealant. Look for bubbling or wrinkling on the membrane and check the flashing for rust, looseness, or gaps.
For a safe DIY diagnosis, check inside your attic after a rainstorm for water stains or dampness near the chimney. On the roof, you can gently run a garden hose over the chimney flashing area to see if water enters the interior; this simulates rain without causing extra damage. Avoid stepping directly on the membrane where possible. If you notice persistent leaks or damaged flashing, it’s best to call a professional roofer experienced with EPDM systems. Ask your contractor specifically how they plan to reseal the flashing to ensure a watertight bond with the EPDM and how they will handle compatibility with the warranty. Another important question is whether they use EPDM-approved flashing materials and installation techniques since using incompatible products can void your roof’s warranty and cause early failure.