Joe Knows Granule Surface Preparation: Hot Air Welder


Hello CertainTeed Crew!

I’m back with another granule surface preparation topic. This session will show you how to prepare a granulated cap sheet using a hot air welder and Flintlastic® SA Self-Adhered Membranes. 

This type of application can be used as an alternative anywhere you are installing granule-to-granule cap sheets for details CT- 06, CT-09, CT-10, and as a replacement to using a caulk adhesive for detail CT-22

How it Works

A hot air welder is required in cold climates – below 50°F – when self-adhering SBS-Modified Bitumen roof systems. It is important to note that a hot air welder can be used when it is 50°F and rising. (CertainTeed approves this.)

Use a silicone or metal hand roller to create a “heat and seal” effect. The heat will adhere to sidelaps, endlaps, and other details. The heat softens the membrane, sealing it to the Flintlastic SA cap sheet, bonding the overlap with the cap sheets. Done correctly, this process creates a permanent and watertight bond. 

Let’s Get Started!

1. Use a hot air welder to heat the bonding surface and use a roller to press the sheet into place. Be sure to set the hot air welder between 8 to 10 or between 932 to 1130°F.

2. Smoke will appear if you are overheating the sheet. If this happens, you will either need to turn down your welder’s temperature or move faster along the sheet.

3. Once the sheet is rolled into place, you will want to see no more than one-quarter-inch bleed out along the edge. 

4. Then, check all joints and laps with a seam probe for full adhesion. 

5. Finally, apply a bead of FlintBond®Caulk along the edge.  

Excellent job. You and your team have learned the next steps for crucial installation details. If you have any questions, you can submit them via this form or comment below. 

For additional information on CertainTeed products and installation, please visit

Want to learn about Torch Applying? Check out my step-by-step guide.

Joe Knows Granule Surface Preparation: Torch-Applied

Starting at the beginning? We’ve got you covered.

Commercial Roofing Construction Detail CT-22: Installing Membrane End Laps

Commercial Roofing Construction Detail CT-06: Base Flashing on a Parapet Wall

Commercial Roofing Construction Detail CT-09: Base Flashing the Inside Corner of a Parapet Wall

Commercial Roofing Construction Detail CT-10:  Base Flashing the Outside Corner of a Parapet Wall

Happy Building, 


Find our Construction Details here:—roof-systems-specifications/

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