Mastering PVC Welding: Crucial Steps for Seamless Results

Precision and attention to detail are key to high-quality PVC welds. Follow these expert tips from Carlisle SynTec Systems for flawless installations.

Account for Ambient Conditions

Temperature, sunlight, and substrate type (e.g., polyiso or concrete) affect welding. Adjust speeds and heat as needed.

Perfect Your Hand Welding Technique

Use a 2” silicone roller at a 45° angle. When welding across a step-off, immediately crease the top membrane to avoid water channels.

Perform Regular Test Welds

Conditions shift throughout the day—do multiple daily test welds. Cut a 1” strip across seams and peel to confirm weld strength.

Check for “Bleed Out”

A good weld shows “bleed out,” where the bottom ply flows from the seam. Lack of it may signal low heat—probe these areas.

Use Membrane Cleaner Wisely

For repairs, use PVC or KEE HP Membrane Cleaner sparingly. Let dry at least 10 minutes before rewelding.

Always Probe Your Seams

After cooling, probe all seams with a blunt-tip tool like the Carlisle Seam Probe. Repair any defects with a hot-air welder by day’s end.

Get More Guidance

Download the Sure-Flex PVC and KEE HP Welding Guide for full instructions.

About Carlisle SynTec Systems

Carlisle has led the single-ply roofing industry for 55+ years, offering top-tier EPDM, TPO, PVC, insulation, adhesives, and accessories.

For more information, please visit carlislesyntec.com.