The distinction is based on the kind of plant involved.
Intensive vs extensive green roof.
15 to 50 per square foot.
Intensive planting there are two ways of planting a roof.
A green roof comes in two varieties.
Semi intensive green roofs require a deeper soil layer but the payoff is in the types of plantings that can be used.
It should be clear from the above which green roof type is best for you.
If you are looking for a low maintenance lightweight green roof that features simple and self maintaining vegetation then the extensive green roof is for you.
Typically these roofs will have more soil and some small shrubs as well as the low growing wildflowers and sedums found on an extensive roof.
In addition to the mosses grasses and sedum of extensive roofs semi intensive plantings include herbs flowering plants taller grasses and small shrubs.
Intensive vs extensive green roof.
These can easily be installed on sheds and garages.
8 to 20 per square foot.
For a conventional roof.
A semi intensive green roof can give rise to a richer ecology with more diverse plant and animal species.
A green roof with a lightweight solution of 30 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 host plants.
Roughly speaking extensive green roofs have a thickness of between 4 and 15 cm and a weight of between 30 and 220 kg m2.
An extensive green roof is characterized by a thinner layer of soil and smaller plants.
These systems range in thickness from 2 6 94 and weigh approximately 15 30lbs per sq ft.
Due to their light weight and low profile they require less structural support and can be used on roofs with a slope of 30 b0 and higher.
A 2006 study by the university of michigan comparing costs of conventional and green roofs showed that on average installing a green roof costs about 22 00 sq.
It also allows for a formal garden to be installed with paths grass lawn and flowers or pot plants.
Intensive includes a thick layer of soil that can support large vegetation such as small trees.