A Review of Green Roof: Definition, History, Evolution and Functions

In cities, buildings contribute large unused panels, especially on their wall and roofs. These external surfaces generally made from materials that listed as a reflector to the heat such as concrete, glass, and bricks. Covering the external surfaces with green vegetation could be a solution to many environmental, economic and social problems, especially in the urban areas. A review was directed of studies that reported and measured on the relationship between characteristics of vegetation and their influence on building thermal performance, air and water pollution, and building energy-efficient. A numerous of published studies were investigated for their: (a) definition based on roof typologies and combinations; (b) historical evolution periods; (c) observation the green system functions. These analyses cover to afford scholars with a review of conventional techniques to understand one of the passive cooling strategies adopted in warm and cold climates. The techniques provide a significant contribution to the field of sustainable architecture, also to improve understanding of the progressive developments of a green roof. Despite other new designs of green system, this conventional and simple green roof has remained to contribute significantly to provide indoor thermal comfort.