What is a Green Roof?
A green roof is a vegetated roof cover that is installed on top of an otherwise conventional roof, giving the roof characteristics that more closely resemble a natural environment.
Ancient green roof technologies have been used for thousands of years. Most noteworthy are the "Hanging Gardens" of Babylon (500 B.C.) and Viking houses.Modern Technologies
Modern green roof technologies were developed in Germany during the 1980s. Currently, about ten percent of German roofs are green and Germany provides indirect and direct subsidies and ordinances for the installation of green roofs.
Vegetated roofs are popular in North American cities such as Chicago, Portland and Atlanta. Chicago's City Hall is one of the earliest examples in the United States. Rockefeller Center in New York City also has a green roof (see below). Many cities are considering different types of incentive programs for the installation of green roofs.