Green Roofs Organization
Green roof system is an extension of the existing roof which involves a high quality water proofing and root repellant system, a drainage system, filter cloth, a lightweight growing medium and plants.
Green roof systems may be modular, with drainage layers, filter cloth, growing media and plants already prepared in movable, often interlocking grids, or loose laid/ built-up where each component of the system may be installed separately. Green roof development involves the creation of “contained” green space on top of a human-made structure. This green space could be below, at or above grade, but in all cases the plants are not planted in the “ground’. Green roofs can provide a wide range of public and private benefits.
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. In Germany for instance, the industry made 700 million DM in sales in 1997, up from 500 million DM in sales in 1994. The industry continues to experience growth with with 13.5 million square metres of green roofs constructed in 2001, up from 9 million square metres built in 1994. In North America, thanks to education and policy support the green roof industry continues to grow rapidly.