TPO Roof Leak Repair

TPO (thermoplastic polyolefin) is one of the most common commercial and residential flat roof membranes installed over the last two decades, valued for its reflective white surface and heat-weldable seams. When TPO fails, it’s almost always at a seam — either the factory seam between sheets or a field seam created during installation or a prior repair.

The correct repair method is hot-air welding: heating both the existing membrane and a new patch of TPO to a specific temperature until the material becomes tacky, then fusing them together under pressure with a roller. This creates a true molecular bond, not just a surface adhesion — which is why generic sealants or caulk applied to TPO rarely hold for long; they don’t bond to the material the way a proper weld does.

Punctures, seam separation, and shrinkage (TPO can shrink over time, especially lower-quality or older formulations, putting stress on seams and penetrations) are the most common issues we repair. Each requires slightly different prep, but all require actual welding equipment and correct technique to hold long-term.