Using birch bark as a waterproof barrier you can
expect a green roof like this to last 30-40 years. The function of
the turf on top of the birch bark is to keep the bark flat and in
Listen to natural builder
view, in the video left, on the living green roof. He says, "When
we put a living roof on the building we create more ecosystem than
the ground that the house took up before the building was there".