2001 Karen Bech  
2003 Amber Hadenfeldt and John Hammond  
Introduction  
The following information on green roofs provides a brief synopsis of the applications, components, construction and cost benefits, as well as a few examples of case studies where successful green roofs have been installed. This report is meant to be a starting point for further investigation into the type of green roof that is appropriate for any given site. Therefore, the resources listed are useful as contacts to obtain specific design and construction information for potential or existing green roofs.  
Acres upon acres of the earth’s surface are occupied by rooftops whose main—and often only—purpose is to protect us from sun and rain. These rooftops are, typically, impervious expanses exposed to high winds and severe microclimates, essentially lifeless deserts even in the wettest climates. Traditional impervious roof systems vastly increase storm runoff, causing flash peak runoff volumes, and contribute to the urban heat island effect. Little if any life can be supported by these environments.

Roofs covered in a veneer of living earth and plants—green roofs—are an ecologically healthy alternative to traditional impervious roof systems. Green roofs replace the lifeless deserts described above with living systems that greatly reduce storm runoff and the heat island effect, provide habitat for insects and birds, and clean the air. When they take the form of rooftop gardens, green roofs can also increase habitable space in the city and provide opportunities to create unique and meaningful places. 		   
Chicago City Hall 2002