TPO (Thermoplastic Polyolefin) roofing is a popular choice for flat or low-slope roofs, often paired with metal chimney flashing to prevent water intrusion where the roof meets the chimney. Leaks around chimney flashing on TPO roofs usually happen due to improper sealing, thermal expansion, or damage from weather exposure. Over time, the flexible membrane can shrink, crack, or pull away from the flashing, allowing water to seep in. Debris buildup or poor installation where the flashing meets the membrane can also create gaps. Diagnosing leaks often means carefully inspecting the perimeter of the chimney flashing and the TPO seams surrounding it for visible cracks, blisters, or gaps. A common safe DIY check involves looking for water stains or dampness inside the attic around the chimney area after rain and gently running a hose over the flashing joints to see if water gets through, but avoid walking on the TPO yourself if you’re not confident.
When you notice signs of leakage, it’s best to call a professional roofer experienced with TPO systems. Attempting complex repairs yourself may void warranties or damage the membrane further. A qualified contractor will check the flashing and membrane seams thoroughly, repairing or replacing damaged sections with compatible materials. When consulting a roofer, ask if they will use a compatible TPO-compatible sealant or welding techniques rather than generic caulk, and whether the flashing was installed according to manufacturer guidelines. Also ask about warranty coverage after repairs to ensure long-term protection. Proper maintenance and timely repairs can keep your chimney flashing and TPO roof watertight for many years.