The number of Green roofs is increasing rapidly every year in the urban areas of Japan to moderate heat island effect and reduce storm water runoff, improve urban scenery, and to create natural habitats. Green roofs can be categorized as intensive, or extensive, depending on substrate depth and maintenance requirement. Due to laws, regulations and subsidies, extensive green roofs have been less frequently used than intensive green roofs. Biodiverse Roofs, which have become popular in Europe as one of an extensive green roof technology, have contributed to the use of recycled materials and the conservation of the ecosystem. In order to study the possibility of the introduction of Biodiverse Roofs to the urban area of Japan, this paper investigates the existing Biodiverse Roofs of the world by studying their history, categorizing their purposes of construction and design methods. Also, the regulations and support systems of local authorities in Japan related to Biodiverse Roofs were surveyed to point out the possible barriers of their implementation.
