They are differentiated on the basis of plant selection growing medium type and overall cost.
Extensive green roof detail.
8 to 20 per square foot.
Extensive green roofing systems consist of lightweight naturalistic planting that provides extensive plant cover with minimal maintenance and a wide range of benefits including.
Little modification of the roof environment ensuring suitability for new or refurbishment applications.
Extensive green roofs sedum roof systems.
For both of these we need to follow specific green roof construction and maintenance procedures.
Extensive green roofs are generally made up of a very thin layer of soil or other planting medium with shallow root plants like sedum mosses and grasses.
The soil is usually not more than 5 deep and is sometimes contained by a tray system which provides a barrier to excessive growth protects the roof membrane and also interlocks the.
Generally there are two types of green roof systems.
Extensive green roofs.
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.
Typically they have thin layers of substrate the growing medium to keep depth and weight to a minimum.
15 to 50 per square foot.
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.
It also allows for a formal garden to be installed with paths grass lawn and flowers or pot plants.
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.
Green roof components growing media water holding capacity field capacity maximum water capacity astm test.
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.
A semi intensive green roof can give rise to a richer ecology with more diverse plant and animal species.
A general characterization of the two types of green roofing systems follows.
Moisture retained by saturated media after free draining 40 60 typ.
For a conventional roof.
These systems are ideal for efficient stormwater.