4. Load-bearing elements and waterproofing

Green roofs can be installed on various types of load-bearing elements: concrete, aerated concrete, ribbed sheet steel, wood and wood-based panels. Whatever the load-bearing element, the loads to be taken into account for its dimensioning are calculated according to the weight of the vegetation complex and the MEC (maximum water capacity) on the structure (§ 4.5 ). Waterproofing must be of the anti-root type, or supplemented by an anti-root device.