How much does a green roof weigh?
The weight of a green roof will depend on the total structure of the green roof system. When preparing a green roof, calculations must always be based on the water-saturated weight of the total structure.
Green roof system structure
Roofs with vegetation blankets consisting of herbs, grasses, wild flowers or host and nectar plants require a thicker substrate layer than a vegetation blanket consisting of only Sedum plants. The thicker the substrate layer, the greater the weight of the total roof structure. In addition the weight also depends on the water buffering capacity of the drainage layer.
Weight of standard Sedum roof
A standard Sedum roof has a saturated weight of about 80 kg/m². If necessary, this weight can be reduced to approximately 40 kg/m² for roofs that can only bear a lightweight green roof system.