What is an extensive green roof?

Under an extensive green roof we also include vegetation that is more or less self-perpetuating and that can further develop and maintain itself.

Difference extensive and intensive green roofs

What is the difference between an extensive and intensive green roof? These roofs differ from each other in the thickness of the structure, its weight and the amount of maintenance that the plants require.

Roughly speaking, extensive green roofs have a thickness of between 4 and 15 cm and a weight of between 45 and 220 kg/m2. A green roof with a lightweight solution of 45 kg/m2 is only possible with Sedum vegetation, and a green roof with a weight of 220 kg/m2 is composed of a combination of Sedum, grasses, herbs or wildflowers

You can compare an intensive roof to a normal garden, and this is why an intensive green roof is also known as a rooftop garden or garden roof. The depth of an intensive green roof ranges from 15 cm to as much as 150 cm, and can easily weigh as much 300 to more than 1500 kg/m2. To bear this weight, an expensive, custom, support structure is required. The vegetation consists of shrubs and trees, often in combination with ground cover. This vegetation requires intensive maintenance to ensure the plants remain in good condition. This maintenance includes watering, pruning, fertilization, weeding, just as in an ordinary garden.