Living roofs may be a newer phenomenon in many places, but Norwegians have been planting greenery atop their houses for hundreds of years. Some have flowers mixed in with grass, creating a lush garden that just happens to keep the house below well insulated. The verdant roofs have many advantages, from maintaining regular temperatures within the dwellings to actually stabilizing the houses themselves … Green roofs have become a long-standing tradition in Norway, and it’s not common to see them dotting the country’s landscape — or in this case, essentially melding with the landscape. During the Viking and Middle Ages most houses had sod roofs, and they were almost universal until the beginning of the 18th century. Tile roofs, which appeared much earlier in towns and manor homes, gradually superseded sod roofs during the 19th century, except in remote inland areas.
Check out the article at inhabitat.com/norway-green-roof-homes/