Comparatively low capital cost.
Extensive green roof construction.
For both of these we need to follow specific green roof construction and maintenance procedures.
Green roofs which are planted and seeded tend to perform better in the long term.
Extensive roofs are lower maintenance that intensive ones and lighter in weight.
There are two types of green roof construction.
Green roofs reduce the temperature of the building and the surrounding air in multiple ways.
They provide shade to the top of a building evapotranspiration.
Vegetative roofs are divided into two categories.
The intensive green roof intensive green roofs are the traditional garden roofs and can support a varied selection of plants.
The plants in a green roof absorb water through their roots and then use surrounding heat from the air to evaporate the water while some roofs can reach temperatures of up to 90 f in the summertime these two features can allow.
Intensive green roofs require a depth of soil of about 600mm require irrigation weeding and care.
The planting medium in extensive green roofs ranges from 1 6 to 6 inches deep and while deeper systems have been installed they are not favored as much as the shallower systems drought tolerant sedums succulent plants and grasses are the typical plants used since they are shallow rooted and use little water plant diversity on these roofs is kept low to simplify care and to be sure all plants have similar moisture requirements.
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.
1 extensive vegetative roofs which are 6 inches or shallower and are frequently designed to satisfy specific engineering and performance goals and 2 intensive vegetative roofs which may become quite deep and merge into more familiar on structure plaza landscapes with promenades lawn large perennial plants and trees.
Green roofs consist of a number of layers including a waterproofing layer drainage layer substrate and planting.
An extensive green roof is the most common and least expensive type of green roof with costs ranging from 10 20 a square foot 2.
They are fairly lightweight and can be installed on roofs with a pitch from 0º to 30º.
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.
A general characterization of the two types of green roofing systems follows.
Green roofs and water quantity buffam and mitchell unpublished data most extensive green roofs will reduce stormwater flows on an annual basis by 50 green roofs also delay stormwater runoff but flow dynamics depend on climate and green roof design.
