The inventor

Stamisol DW roofing underlay was invented 30 years ago as the first diffusion-capable (or in other words breathable) roofing underlay developed especially for mountainous areas. Since then it has had a proven track record in delivering excellent protection from the elements and outstanding durability in a number of Projects.

Patrick Lindt, the previous head developer at Stamoid AG (the predecessor of Serge Ferrari AG, Eglisau, Switzerland) remembers how Stamisol DW was invented:

Fully functional roof wanted

Many physicists involved in construction engineering were aware of this challenging roof design. What was really required was a membrane as the outermost roof shell underneath the tiles. Ideally it was to be waterproof, but capable of diffusion at the same time. This was the only way of designing functional insulated roofs so that the spaces underneath could be converted and used as areas to live in. This was an ever-popular trend at that time in order to gain extra living space in buildings.

The key to breathability

I was an engineer recruited for this development project to turn this type of diffusion-capable roof underlay into reality. A meeting in spring 1982 with Mr Walther from Walther Bauphysik, Biel, put us on the right track. They wanted to create a product that was so breathable that you could blow through it (using the soapy water test).
At the same time, it was to be waterproof and fulfil a number of other requirements, such as being highly resistant to ultra violet rays and windproof etc. One year later in November 1983, we had already come up with a product that met these sophisticated demands and registered the DW F4120 roofing underlay for patent.

Before the official production presentation, luck was on our side. At the time, the German Association of Roofers published a new standard that made ventilation behind roof sheets mandatory. Based on the rules of construction physics this appeared absolutely vital when using bitumen and similar roof underlay.

Premiere at DACH + WAND 1984

The ground-breaking DW F4120 roof underlay was officially presented to industry professionals at exhibition Dach & Wand 1984 in Hamburg. And of course this membrane complied with all demands that required it to be waterproof, windproof, resistant to UV rays and above all diffusion-capable. And the best thing was that ventilation from the back was no longer necessary. People even went as far as calling the new German standard outdated which resulted in the whole board of the German Association of Roofers visiting the Stamoid stand at the trade fair…

From roof underlay to an all-in-one system

The product experienced minor teething problems which became apparent in real-world conditions for the first time. However, these were quickly got rid of and no longer emerged in the subsequent F4250 model in 1985. The company now had a roof membrane with superb features which could now be launched onto the market. At the same time a guarantee agreement was signed with the German Association of Roofers. We held lots of presentations all over the country to persuade roofers and carpenters of the advantages of this new roof underlay. The idea was for me to give these presentations myself in order to harness my development expertise to answer even the most demanding of questions and impress the customers. This was a strategy that proved very successful. At one of these presentations, a member of the audience asked about accessories which gave us the idea of developing an extensive range of accessories (e.g.connecting sheets, ventilation pipe flashings etc.) for reliable fitting of conjunctions. As a result, Stamisol DW quickly became an all-in- one roof underlay system.

Stamisol DW: The original product for over 30 years

Stamisol DW – the original product among diffusion capable roof underlay has now been on the market unchanged for over 30 years. It is long-lasting roofing underlay which perfectly and reliably responds to the demands made and consequently comes with an extensive 10-year warranty.