15 to 50 per square foot.
Intensive extensive green roof.
They fall into three main categories extensive intensive and semi intensive.
You can compare an intensive roof to a normal garden and this is why an intensive green roof is also known as a roof garden or garden roof.
Extensive green roofs traditionally support 50 120 kg m 2 10 25 pounds per square foot of vegetation 45 while intensive roofs support 390 730 kg m 2 80 150 pounds per square foot of vegetation.
Typically they have thin layers of substrate the growing medium to keep depth and weight to a minimum.
Green roofs can be categorized as intensive semi intensive or extensive depending on the depth of planting medium and the amount of maintenance they need.
Besides the visual impact of an extensive green roof they also provide a natural habitat for birds and insects.
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.
For a conventional roof.
Intensive green roofs require the deepest soil and have the greatest impact on the structural design but they also accommodate all types of plantings including large shrubs and trees.
Urban agriculture on green roofs would be considered an intensive green roof as they need regular maintenance relatively deep soils and a certain amount of irrigation.
A typical growing medium depth of an intensive green roof is 6 inches or more.
To bear this weight an expensive custom support structure is required.
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.
Intensive green roofs have more soil and a deeper growing medium sometimes several feet that can support a more diverse plant selection including small trees.
These are covered with low growing plants such as evergreen sedums.
Although there are no precise definitions of them an extensive green roof has a shallow growing medium usually less than six inches with a modest roof load limited plant diversity minimal watering requirements and is often not accessible.
8 to 20 per square foot.
To start with take a look at the most simple family of green roofs.
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.
Gardens and parks on roofs can store a great deal of water and are therefore good sustainable urban drainage systems suds for stormwater management.
Intensive systems allow the designer to create a park like setting so they are the best option for roof gardens that will be occupied.
Extensive green roofs sedum roof systems extensive green roofs are designed to be low maintenance lightweight systems with no general access.
