Welding Bitumen

A worker wearing a red safety helmet operates a green automatic welder to seal roofing sheets on a flat industrial rooftop, with HVAC units and green landscape in the background.

Cap sheets on roofs are usually referred to as modified bitumen. This widely used roof covering is usually comprised of sand, gravel or slate chips added to increase abrasion and UV-resistance.

Modified bitumen is either laid as a single strip on gazebos and sheds or as thicker sheets for flat roofs on large industrial buildings. Leister welding machines are a simple and safe hot air alternative to open flame welding, in particular for bitumen membranes, the thicker roofs made with modified bitumen.

This thicker type of bitumen membrane is also used for roofs on residential and commercial buildings.

Bitumen Welding with Hot Air Technology

Rooftop installation of bitumen membranes using an automatic BITUMAT B2 hot air welding machine, demonstrating efficient seam sealing for flat roofing applications.

Welding considerably thicker, modified SBS and APP bitumen sheeting with the flameless BITUMAT B2 from Leister is much safer, more cost-effective and more efficient than working with an open flame.

Only one procedure is required by a single person, compared to working with an open flame, which requires two individuals.

Open Flame vs. BITUMAT

Side-by-side photograph illustrating seam quality differences between open flame and BITUMAT B2 hot air welded bitumen membranes, with BITUMAT B2 producing a cleaner,

Flameless welding with hot air gives considerably better welding results than using an open flame. The welding seam is straight and considerably narrower (also see images).

Peel Test: Flame vs. BITUMAT

Bar chart comparing peel strength test results of different waterproofing membranes, showing higher values for BITUMAT B2 (EN 12316-1) hot air welding versus open flame method for multiple product types.

Working with the BITUMAT B2 also gives considerably better results in the peel test comparison between BITUMAT and open flame.