Intensive green roofs
Intensive green roofs have a thicker substrate layer and therefore also carry more weight. The thickness of the substrate layer depends on the desired vegetation. This can vary from grass/herbs to trees. Intensive green roofs generally require an irrigation system and regular maintenance, just as ordinary gardens do. Because intensive green roofs require irrigation it is advised to capture the rainwater which is not absorbed by the substrate layer and to use this for irrigation purposes.
Because of the endless design possibilities of intensive green roofs, only general statements can be made regarding the efficiency in terms of water management, heat stress and biodiversity. Attention must be paid to the design of intensive green roofs so as to require as little irrigation as possible using drinking water.