Learn about Optigr?n international AG / Optigreen in The Greenroof Directory.
Here is an Optigr?n project with a slope greater than 70%! It is referred to as a “green ski-slope” at the Betonwerk Eisack Headquarters in Klausen.
In 2010, a second Betonwerk Eisack branch located approximately 25 miles from the headquarters had greenroofs installed with solar panels. See the Betonwerk Eisack (Concrete Factory), Varna project profile here.