To start with take a look at the most simple family of green roofs.
Extensive green roof system.
Green roofs are also known as vegetative or eco roofs.
The heart of the nophadrain extensive green roof system the nd 4 1h drainage system is the ideal under layer for an extensive green roof.
This multifunctional ce marked drainage system with high compressive strength protects the vegetation from water stagnation while at the same time storing water for dry periods in the built in water reservoir.
Extensive green roofs sedum roof systems.
They fall into three main categories extensive intensive and semi intensive.
These are covered with low growing plants such as evergreen sedums.
For a conventional roof.
Finally the extensive green roof is a system that is generally inaccessible to pedestrians.
Extensive roofs are typically lightweight and can be installed over a variety of structures including metal roof decks.
Extensive semi intensive and intensive green roofs.
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.
The biggest benefit of extensive green roofs is that they need very little maintenance.
Typically they have thin layers of substrate the growing medium to keep depth and weight to a minimum.
Besides the visual impact of an extensive green roof they also provide a natural habitat for birds and insects.
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.
8 to 20 per square foot.
These systems are ideal for efficient stormwater.
15 to 50 per square foot.
Three types of green roofs exist.
Extensive systems weigh anywhere from 10 to 25 pounds per square foot when dry which is why the interlocking system of trays is important otherwise strong winds could very easily blow the plantings away.
Extensive green roofs.
Extensive green roofs are designed to be low maintenance lightweight systems with no general access.
An extensive garden roof assembly can be applied to flat roofs and sloping roofs with a pitch of up to 12 12 or 45 provided the appropriate measures are taken to cope with the shear forces and soil retention.
From a distance an extensive sedum roof can be mistaken for a grass field.