Portland, a leader in green building initiatives, requires new city-owned buildings and existing buildings in need of a roof replacement to install a green roof on at least 70% of the roof area.

Green Roof
Source: National Research Council, Institute for Research in Construction

In North America, the benefits of green roof technologies are poorly understood and the market remains immature, despite the efforts of several industry leaders. In Europe however, these technologies have become very well established. This has been the direct result of government legislative and financial support, at both the state and municipal level. Such support recognizes the many tangible and intangible public benefits of green roofs. This support has led to the creation of a vibrant, multi-million dollar market for green roof products and services in Germany, France, Austria and Switzerland among others.

Green Roofs for Healthy Cities’ annual survey of its corporate members found that the green roof industry in the U.S. and Canada increased 115% between 2010 and 2011. The annual growth rate is derived by averaging the square footage of green roofs installed by a representative sample of corporate members.