Pub. date: 2011 | Online Pub. Date: May 04, 2010 | DOI: 10.4135/9781412973816 | Print ISBN: 9781412996822 | Online ISBN: 9781412973816| Publisher:SAGE Publications, Inc.About this encyclopedia
A green roof is the roof of a building that is covered with vegetation and soil or another growing medium. Other layers such as a waterproofing membrane, a root barrier, or drainage and irrigation systems are often included as well. Sometimes referred to as rooftop gardens, ecoroofs, or vegetated roofs, green roofs are becoming increasingly popular for their environmental, economic, and aesthetic benefits. The benefits attributed to green roofs are numerous. The first is energy efficiency. By providing a layer of insulation and absorbing the heat of the summer sun, green roofs have been found to lower energy requirements for cooling and heating buildings significantly. Green roofs can reduce the urban heat island effect and can reduce air pollution, as the vegetation filters both particulate matter and carbon dioxide. Another benefit of green roofs is that they reduce a city's impervious surface area. By absorbing rainfall, green roofs can help ...