Top 10 No 5

Low-Slope Roofing Mistake No. 5: Angle-Change Voids

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Experienced thermoplastic membrane welders know how important it is to get angle changes right. If the flashing isn’t tight at the angle change, you can wind up with bridging — a void between the vertical flashing and the roof deck. Unaddressed, bridging can cause the flashing to pull loose and lead to water infiltration. 

In this segment of the Roofing it Right miniseries on the Top Ten Mistakes in Low Slope Roofing, GAF Senior Commercial Training Specialists Dave Scott and Wally Brown explore the causes of bridging, as well as best practices to deal with it and — more importantly — how to prevent it.

Key tips include: 

  • Clean the membrane before welding
  • Make sure to get the angle tight
  • Always start welding at the backside angle change and work your way out from there

Check out the episode here:

And be sure to check out the entire top ten list, along with the complete collection of entertaining and educational Roofing It Right episodes (muchos de ellos disponibles en español), at

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