Extensive Green Roof Thickness
They fall into three main categories extensive intensive and semi intensive.
Extensive green roof thickness. Vegetative roofs are divided into two categories. The substrate is usually an aggregate mixed with about 20 organic material. The nominal thickness of a green roof is the approximate total height of the soil and drainage components that constitute the green roof system excluding the roof structure insulation waterproofing and plants. It is common practice to use the term extensive to describe green roofs that are very thin and will only support hardy drought resistant vegetation such as sedums herbs and perennials.
Extensive green roofs are simpler lighter weight systems commonly seen on residential buildings. A green roof with a lightweight solution of 30 kg m2 is only possible with sedum vegetation and a green roof with a weight of 220 kg m2 is composed of a combination of sedum grasses herbs or host plants. Intensive to describe green roofs that are thick enough. These extensive green roofs generally have 80mm of substrate.
Green roofs are also known as vegetative or eco roofs. 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. Roughly speaking extensive green roofs have a substrate thickness of between 4 and 15 cm and a weight of 30 to 220 kilo per m2. Cincinnati civic garden center roof example rain event 12mm from july green roofs and water quantity.
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. The vegetation layer consists of sedums and wildflowers. Used vegetation consists of hardy weather resistant plants that can adapt to extreme climates. 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.
Roughly speaking extensive green roofs have a thickness of between 4 and 15 cm and a weight of between 30 and 220 kg m2. 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. An extensive green roof or sedum roof is a roof with vegetation that is more or less self perpetuating and that can further develop and maintain itself. The concept of extensive green roofs is to design a rugged durable roof that requires little maintenance and no human interaction.
Although there are no precise definitions of. What is a green roof. The substrate sits on the green roof system filter sheet drainage layer protection layer.