在城市利用平屋顶进行绿化对改变人们赖以生存的空间、阳光和生态环境条件能起到积极作用。为此,要达到增加绿化系数、净化空气、降温、保暖、点缀街景的目的,就必须要配置植物,充分发挥绿化的生态效果、环境效果和经济效果。同时,要根据屋顶的结构和承重能力,做到因“顶”制宜,确保安全。上海市区平屋顶绿化的形式地毯式利用矮灌木或花草覆盖顶面。一般是在水泥屋顶上铺一定厚度的人造土(发酵的土屑土),种上植物,尤如在屋顶上铺了一层“生物地毯”。夏季降温、冬季保暖效果显著。花坛式由若干花坛组成开放 Greening with flat roofs in the city can play a positive role in changing the space, sunlight and ecological environment in which people depend. To this end, in order to achieve the purpose of increasing the greening coefficient, purifying the air, cooling down, keeping warm and embellishing the streets, plants must be deployed to give full play to the ecological effects, environmental effects and economic effects of greening. At the same time, according to the roof structure and load-bearing capacity, so as to “top”, to ensure safety. The Shanghai urban flat roof green carpet form the use of dwarf shrubs or flowers cover the top. Generally, a layer of artificial soil (fermented soil) is planted on cement roofs and planted with plants, as if a “bio-carpet” has been laid on the roof. Summer cooling, winter thermal effect is remarkable. The flower bed is made up of several flower beds