Kaegiswil, Switzerland

Leister Technologies AG were scheduled to refurbish an existing roof waterproofing system that was more than 20 years old. They also decided to invest in making this a new Solar PV Roof to generate their own power and contribute to sustainable growth with renewable energy. The innovative new Sarnafil® AT roofing membrane was selected for this roof refurbishment project.​ Our customer’s wishes, their experiences with our systems and their installation are always very crucial feedback for Sika. Therefore, following completion of these works on the Leister site, we have conducted feedback interviews with key project participants.

Interview with Bruno von Wyl, Chief Technology Officer, Leister Technologies AG

Why did you choose Sarnafil® AT? ​
We regard the durability and long-term performance of a roof as key criteria and the reason we selected Sarnafil® AT. This system is also highly resistant to mechanical damage, flexible and easy to weld, which are attributes that make an owner comfortable that they will have a watertight roof for many years. Sika has been in the roofing business for more than 60 years and is recognized as a leader in roofing technologies and as a solid partner world-wide, as are Leister, so we are convinced that Sarnafil® AT is the right choice for this important project. ​

​How important are sustainability and environmental protection for Leister?​
Extremely important! We are convinced that we must take responsibility and contribute to environmental protection. This is also why we are investing to make this a Solar PV roof.​

​Would you recommend the Sarnafil® AT system to other building owners?​
Yes, we are fully convinced of the advantages and very satisfied with the results.​

Construction workers on the roof of Leister Technologies AG

Interview with Roofing System Installation Supervisor, Paul Röthlin

What was your experience with the Sarnafil® AT membrane system, especially in terms of its weldability, flexibility, application speed?​
The Sarnafil® AT membrane is extremely easy to weld and with the wide welding window the installer can easily achieve the right parameters. This creates confidence and a good weld can be achieved in a relatively short time, which increases the overall installation rates.​ Additionally, the Sarnafil® AT is highly dimensional stable, even at lower and higher temperatures. For example, on site we measured membrane surface temperatures changes of up to 80° C between day-time highs and night-time lows, and no wrinkling was visible on Sarnafil® AT​.

Refurbishment works on the Roof Leister Technologies AG Roof
Construcion lady applying Sarnafil AT during Leister Technologies roof refurbishment

​Would you recommend Sarnafil® AT to other roofing installers and contractors?​
Yes definitely, we are very satisfied.​ Due to the flexibility of the Sarnafil® AT membrane, plus use of the new self-adhered system, the installation time was significantly reduced, and the roof was completed on time, or even before originally scheduled.

​How was the support from Sika regarding site training, detailing solutions, response time for any questions, etc. ?​
I was very pleased. We received very professional support from Sika's Technical Services people throughout the site installation works. The initial training on-site was also good at creating trust and confidence for the new product line. The collaboration was all very good. ​

How was the membrane processing speed compared to other common roofing membranes, e.g. the self-adhesive membrane for the upstands?​
The application of the self-adhered Sarnafil® AT membrane on the parapets was very easy, even though we were doing it for the first time. Another plus for the self-adhered AT technology is that you do not need any chemical products on the roof – So the installation is totally free of solvents - which also supports Leister’s environmental protection initiatives.

Project Requirements

Leister Technologies AG decided to invest in a new Solar Roofing solution to generate its own solar power and therefore to contribute to a sustainable growth in renewable energy. As the existing roof was for more than 20 years in operation Leister decided to choose a roofing partner offering a long-lasting and environmentally friendly roofing system.
Sika has a proven track record for more than 50 years in offering a reliable roofing solution. Sarnafil® AT, a new revolutionary thermoplastic roofing membrane technology, was chosen to be the right system as it’s the first single ply roofing membrane in the world being rigorous Cradle-to-Cradle CertifiedTM. Through this innovative products, Sika is committed to design, measure and communicate sustainable value creation – the right solution for Leister.

Sika Solutions & Products Used

Roofing area: Sarnafil® AT
Upstands: Sarnafil® AT FSA P (self adhered)
Insualtion: EPS / tapered PIR
Vapour Control Layer: Dörr-Tiralbit AL-E sk/Safeguard (self adhered)
Roofing structure: Trapezoidal metal deck

Project Participants

Leister Technologies AG


Mathis Flachdach AG

Sika Organization

Sika Schweiz AG

Size in m2:
2,000 m2

Refurbishment of Leister Technologies AG Roof
Refurbishment of Leister Technologies AG Roof

Learn more about Sarnafil® AT

Woman standing on a rooftop with arms wide open, having a whole city under her foot.

Sarnafil® AT Advanced Technology

The new patented hybrid Sarnafil® AT technology refers to a versatile membrane that is easy-to-apply and long-lasting for sustainably designed roofs.