If you are embarking on a "green roof project" then these are the guide lines on the typical weight once installed.
There are two types of green roof which allow for the growing of different types of plants. The most popular is a green roof system called "extensive". This is the lightest of the both with a load of 70 - 170 kg per square meter once planted. The big variation in load is due to substrate depth ( substrate is the growing medium, what the plant roots will grow in) An extensive green roof is also suitable for projects around the garden such as planting your shed / garage roof and storage units.
An intensive green roof has a deeper substrate, allowing for a greater range of plants to grow and the load per square meter is between 290 and kg on the existing roof structure.
If you are embarking on an extension or new garden design then give a green roof some consideration, what is better to look at, a grey asphalt roof or an attractive planted Sedum green roof?
