Green Roofs - GreenSpec

existing green roof practice and focuses on its value for biodiversity, particularly in the urbancontext.Figure 1 Multifunctional Urban DesignGraphic: Studio Engleback2. Overview2.1 DefinitionsThe term green roof is used here to describe both intensive ornamental roof gardens andextensive roofs with more naturalistic plantings or self-established vegetation. Brownlie(1990) has defined a roof garden as an area of usually ornamental planting with a substrateisolated from the natural ground by a man-made structure of at least one storey. We extendthat definition to roofs that have been initially planted and/or sown, as well as those that havebeen allowed to colonise and develop naturally. They do not necessarily have to beornamental in function. Eco roof is a term usually used to describe a naturalistic extensivegreen roof (see ‘Categories of Green Roof’ below for explanation of extensive and intensive).The term spontaneous green roof is used to describe a roof covered with self-establishedvegetation.When the exterior walls (facades) of buildings are vegetated they are known as greenfacades. Masonry may become colonised by lichens, mosses, grasses and flowering plantsthat in nature grow on cliffs and rocky outcrops. Climbing plants may grow directly againstthe building fabric or may climb trellis work. Geotextile blankets may be attached to wallsand seeded with moss or Sedum. It is even possible to grow reedbeds in fabric pocketsattached to walls.Earth-sheltered structu res are set into the ground, with a continuous earth cover replacing atleast part of what would be the walls and roof of a conventional building. Such buildings areusually well vegetated and blend well with the landscape and are usually associated withrural locations. Earth-sheltering is outside of the scope of this report.10