What are they?
We call green roofs to any exterior surface of cover that this prepared to shelter vegetable species and that is being able to use as terrace, court, playtime zone, infantile ….
Depends on the structure of the building and of what allows the roofs there is no limits in what to the architectural and landscape design it refers. All that without having to acquire additional area for what they suppose an important saving and an attractive resource to have green spaces in private properties, companies or public works.
The landscaped roofs, as we know them nowadays, has its origin in Germany more than 30 years ago.