Around 50 years ago there was trend in the USA of having Norwegian Log Cabins as a second home.
All of these cabins came entirely from Norway and they all had a Green Roof. Most of these cabins with timber from Norway still exist and the owners are very proud of having these solid, cozy and unique structures.
Unfortunately most of these Green Roofs have been replaced by metal roofing during the last 20 years.
Nevertheless the simple Green Roof systems (without plastics) lasted at least 3 decades without major maintenance and without any irrigation systems. Even Fire Marshals never had an issue with this unique long lasting roofing solution.
Around 12 years ago I had the honor to meet a building owner, who wanted a Green Roof back and as it was originally designed. The project was near Washington, DC and meanwhile the building was surrounded by 60 feet tall trees and entirely in the shade. The structure was still able to carry around 30psf for the Green Roof.
Rather common in the USA: Norwegian Log Cabins
Finally, with a new roofing and a divided drainage system in a multilayered, seamless Green Roof the owner was satisfied with the result. Look at the picture (from 2015) and tell me what you think.
There is no irrigation system, no single source warranty, very limited use of plastics and very limited maintenance.
By Jörg Breuning
