With Leister – At Leister – For Leister

Leister Insight24 Jun 2020

The roof of the Leister Group headquarters in Kägiswil, Switzerland is due for renovations at some point, like so many other roofs around the world. This welcomes the opportunity for our roofing professionals to use their equipment directly at our headquarters.

Author: Silke Landtwing, Manager Corporate Communications, Leister Switzerland

It is precisely under this roof that UNIDRIVE 500, VARIMAT V2, UNIROOF AT, UNIROOF ST, TRIAC AT and many other tools, are developed by our creative minds. It is even possible for our wise roofers to come up with a new idea to expand the proven roofing product line while renovating our roof.

Weather has been a significant factor in our ability to start welding the new roofing membranes. The roofers from Mathis Flachdach AG and Leister's professionals have been waiting for two weeks for the rain to finally stop. It is important that the new roof is installed in dry conditions to produce impenetrable welds across 2000 m2 / 21'528 ft2 of flat roof. In addition, our marketing crew wants to film and photograph the spectacle, which is definitely more fun when the weather is good.

Welding the Vapor Barrier


On June 18th, the clouds had dispersed and the roofing work finally began. Valérie Bergerot, from Leister's marketing department, was allowed on the roof to photograph Natascha Mathis welding the so-called vapor barrier. A big thanks to Natascha for allowing us to photograph her while working.

What a Vapor Barrier is and How does it Work

Leister's roofing specialist, Paul Röthlin, explained the basics of roofing, what a vapor barrier is and how it works.


Simply put, the vapor barrier is an important layer of protection that is needed on every roof to prevent moisture from penetrating. Since the vapor barrier prevents too much moisture from penetrating the insulation, it is impermeable to water vapor on the inside and outside. Therefore, it is moisture-variable, which results in the following effect:

  • If the humidity of the outside air is higher than that of the inside air, the vapor barrier releases the excess moisture accumulated in the insulation to the inside.
  • If it is the other way round, i.e. if the humidity of the indoor air is higher than that of the outdoor air, the vapor barrier allows the moisture to diffuse outwards.

How to Continue

According to the plan, the roof should be finished by the end of July. Due to the rainy weather, work is currently 14 days behind schedule, making it a challenging task to complete. Let's see if we can do it!

You can read about the progress of the roof in our news blog in July.