roof and pavement consultants

Observation From The Field: Tack Welding TPO Membrane

Benchmark Service: Construction Phase Services

Issue: The Contractor was using a practice called “tack welding” of TPO membrane during installation on windy days to hold the membrane in place.  This can result in damage to the membrane and result in leaks.

Solution: Benchmark notified the Contractor and Manufacturer of the potential risks associated with this practice.  Initially, the Membrane Manufacturer’s Representative defended the practice.  Benchmark contacted the Manufacturer’s Technical Director, who then agreed that tack welding should not be done.

Possible Impact: In a wind event, these tack welds may separate and cause significant damage to the roof membrane while allowing moisture in the roof system.  By identifying these issues during daily inspections, the risk of future damage and leaks has been reduced.

Damaged membrane from a tack weld. Membrane separation at a tack weld.

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