Structure and Functions of Green Roof and Its Development in Urban Areas, China

Abstract

The green roof is an environmentally friendly design, which is important for sustainable development and improvement of resilience in urban areas. This paper offers a systematically review of the classification, material selection, functionality, limiting factors of green roofs, and provides suggestions. The green roof is classified into intensive, extensive and semi-intensive ones according to the substrate depth and vegetation type. Its basic structure includes vegetation, substrate, filter, drainage, protection, anti-root, insulation and waterproofing layers from top to base. Among which, vegetation, waterproofing and drainage are vital layers to decide the roof efficient. The factors such as light, temperature and humidity conditions of the site are vital for determination of vegetations for a green roof. Green roofs provide benefits for urban areas via saving energy, reducing stormwater runoff and improving aesthetic. Roof load-bearing, seepage, survival of vegetations and support from all sectors are the main issues for the development of green roofs at current stage.