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Glossary of green roof terms


Biodiverse Roof Wildlife or brown roof designed to either replicate the habitat for a single or limited number of species or to create a range of habitats to maximise the array of species which inhabit the roof. Brown Roof Biodiverse or wildlife roof designed to either replicate the habitat for a single or limited number of species or to create a range of habitats to maximise the array of species which inhabit the roof. BSi British Standards Drainage Layer / Reservoir Board Part of the standard green roof build-up which allows excess water to drain away to the downpipe outlets. Some drainage layers also provide a reservoir effect to retain moisture for a longer period to help maintain. Drainage layers may be made of a variety of materials including hard plastic, foam or coarse gravel. DIN Standards Deutsches Institut für Normung which means "German Institute for Standardization". DIN Standards are the published results of DIN's work. Extensive Green Roof Low nutrient and low maintenance, also often designed to be light weight. Not irrigated. Usually shallow substrate, typically less than 100mm, and often vegetated with sedum. Filter Fleece / Fines Layer Part of a standard green roof build-up which prevents fines and sediments from being washed into the drainage system. FLL Forschüngsgesellschaft Landschaftsentwicklung Landschaftbau's (German Landscape Research, Development and Construction Society) Green Roof A roof or deck onto which vegetation is intentionally grown or habitats for wildlife are established, including: extensive, intensive and semi intensive roofs; roof gardens; biodiverse roofs; brown roofs; public and private amenity spaces. The Green Roof System. The layers of material which make up a green roof build-up. Growing Medium / Substrate An engineered soil replacement specifically designed to give green roof plants what they need and to survive and to allow water to be absorbed and to drain away. Substrates contain specified ratio of organic and inorganic material. GRO Green Roof Organisation The industry forum for green roof development and promotion in the UK, facilitated by the NFRC. Hydro Seeding Spraying a specially designed blend of seeds and growing medium. HSE Health and Safety Executive Intensive Green Roof A green roof that requires intensive maintenance. Usually irrigated and usually with more than 200mm depth of substrate. Equivalent to a garden and usually referred to as a roof garden. Protection Layer Relatively thick (2mm) geotextile blanket which provides protection to the waterproof membrane while the other parts of the green roof system are being installed. Reservoir Board / Drainage Layer Part of the standard green roof build-up which allows excess water to drain away to the downpipe outlets. Some drainage layers also provide a reservoir effect to retain moisture for a longer period to help maintain. Drainage layers may be made of a variety of materials including hard plastic, foam or coarse gravel. Root Barrier A standard feature of a green roof. A membrane or layer designed to prevent roots from penetrating the waterproofing layer and building fabric. Sedum A genus of about 400 species of low growing leafy succulents which are drought tolerant and found throughout the northern hemisphere. Not all species are suitable for roofs. Semi Intensive Green Roof Intermediate green roof type with characteristics of both extensive and intensive green roofs. Typically 100mm to 200mm substrate depth, sometimes irrigated, occasionally managed, and usually planted with a range of species. Standard / Traditional / Conventional Roof Un-vegetated and non-absorbent roofs i.e. asphalt, single ply, mineral felt, liquid applied, metal deck etc. Substrate/ Growing Medium An engineered soil replacement specifically designed to give green roof plants what they need and to survive and to allow water to be absorbed and to drain away. Substrates contain specified ratio of organic and inorganic material. SUDS Sustainable (Urban) Drainage Systems System The term given to the combination of layers in a green roof build-up. Vapour Barrier Typically a plastic or foil sheet that resists diffusion of moisture through wall, ceiling and floor in a buildings. Wildlife Roof Biodiverse or brown roofs designed to either replicate the habitat for a single or limited number of species or to create a range of habitats to maximise the array of species.