2.2 Green roof

2.2 Green roof Green roof can the defined as a roof that contains plant or vegetation and it may be fully or partially covered on the roof and it’s an addition on a normal concrete decked roof (Rufai Mohammed Ahmed, 2016)(Dvorak, 2010). The top layer is the vegetation stratum, followed by growing medium or soil layer, irrigation layer, filter fabric layer, drainage layer, waterproofing membrane layer, and then the roof deck (Dunnet & Kinngsbury, 2004, Ouldboukhitine et al, 2011) (Rufai Mohammed Ahmed, 2016). A green roof in common language is the roof which is totally or partially covered with vegetation. The vegetation is acquired by placing the layer of planting media above a waterproofing layer. Green roof consists of different layers such as root barrier, insulation, water proofing layer, drainage and irrigation system. Green roof has various benefits such as insulation from heat, creating habitat for wildlife, catering rainwater, creating healthy environment by proving landscaping elements and change is micro-climate. High-rise buildings are now-a-days the most focused portion of society to provide green roofs as there is less space for proper landscaping on ground. The only option left is either roof or balconies and walls (as discussed above about green walls). Stepped terraces and extended balconies also comes under green roof classification because of the fact that they are on the horizontal zone.

Figure 14- Diagram showing the layers of green roof. Source- (Landscape Architecture, 1969)

Green roofs can be briefly divided into two parts that is intensive green roof and extensive green roof. Sometimes there is a mixed type that is used called semi-intensive green roof.