Extensive Green Roof System

There are two main forms of green roofs intensive and extensive.

Extensive green roof system.

A green roof is an additional roof system on top of an existing roof made up of a layer of planted vegetation. 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. 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. 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.

Extensive green roofs are designed to be low maintenance lightweight systems with no general access. 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 entire system together to prevent wind damage. 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.

Intensive roofs take more time to manage as they can hold up to 150 pounds of vegetation per square foot. They fall into three main categories extensive intensive and semi intensive. Typically they have thin layers of substrate the growing medium to keep depth and weight to a minimum. The growing medium depth for an extensive green roof system is typically 6 inches or less.

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. Increased water retention and soil depth provide for a wider range of plant choices and a more dynamic visual effect. Green roofs are also known as vegetative or eco roofs. Vegetation growing in a shallow 3 to 6 inch layer of lightweight soil medium contained in a special assembly system over a waterproof membrane.

Extensive roofs are typically lightweight and can be installed over a variety of structures including metal roof decks.