Green roofs, also known as eco roofs and nature roofs, are vegetated roof coverings consisting of living vegetation on top of a modified conventional roof system.
Extensive systems are similar in weight to conventional gravel roofs and can be installed on any roofing deck, flat or sloped up to 45 degrees. Heavier intensive systems, which can include landscape planters and walkways, are intended for flat roofs with additional structural support.
The sod roofs and walls of buildings in Iceland provided the inspiration for the green roof concept. The technology emerged in Germany over 30 years ago and is in widespread use across Europe.