Although there are no precise definitions of.
Extensive green roof and intensive green roof.
A green roof is a layer of vegetation planted over a waterproofing system that is installed on top of a flat or slightly sloped roof.
These systems are ideal for efficient stormwater.
Extensive green roof an extensive green roof system is characterized of its vegetation ranging from sedums to small grasses herbs and flowering herbaceous plants which need little maintenance and no permanent irrigation system the growing medium depth for an extensive green roof system is typically 6 inches or less.
It also allows for a formal garden to be installed with paths grass lawn and flowers or pot plants.
15 to 50 per square foot.
They fall into three main categories extensive intensive and semi intensive.
Green roofs are also known as vegetative or eco roofs.
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.
8 to 20 per square foot.
A properly designed and installed extensive green roof system can cost 108 248 m 2 10 23 sq ft while an intensive green roof costs 355 2 368 m 2 33 220 sq ft however since most of the materials used to build the green roof can be salvaged it is estimated that the cost of replacing a green roof is generally one third of the initial installation costs.
For a conventional roof.
What is a green roof.
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.