Indicator ES.2.f Proportion of buildings with green roofs
| Limited data for this indicator has been collected in San Francisco. |
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| Green roofs in San Francisco* | |||||
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| Name of building | Address | Status | |||
| 2007 Idea House by Sunset Magazine | 3028 25th Street | Complete | |||
| Condos developed by Lorax Development | 23rd Mission Street | Complete | |||
| California Academy of Sciences | Middle Drive East & Martin Luther King Jr Dr | Proposed | |||
| Heron's Head Park Environmental Education Center | Hunter’s Point | Proposed | |||
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*Known locations of green roofs, therefore there could be additional green roofs in San Francisco that are not listed. Data provided by San Francisco Green Roof Task Force.
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Data Source
The Green Building Program of the San Francisco Department of the Environment plans to collect information on green roofs in the future.Explanation and Limitations
According to the U.S. Environmental Protection Agency, "green roofs consist of vegetation and soil, or a growing medium, planted over a waterproofing membrane. Additional layers, such as a root barrier and drainage and irrigation systems may also be included. Green roofs can be used in many applications, including industrial facilities, residences, offices, and other commercial property. In Europe, they are widely used for their stormwater management and energy savings potential, as well as their aesthetic benefits.
Green roofs can reduce the increased heat of urban areas termed the urban heat island effect. This effect is generally due to tall buildings blocking the cold air, increased surface materials such as concrete and glass, and limited evapotransporation. Green roofs reduce the surface area of heat absorbing concrete and through evapotranspiration increase the release of water from plants to the surrounding air. They also:
- Reduce sewage system loads by assimilating large amounts of rainwater.
- Absorb air pollution, collect airborne particulates, and store carbon.
- Protect underlying roof material by eliminating exposure to the sun's ultraviolet (UV) radiation and extreme daily temperature fluctuations.
- Serve as living environments that provide habitats for birds and other small animals.
- Offer an attractive alternative to traditional roofs, addressing growing concerns about urban quality of life.
- Reduce noise transfer from the outdoors.
- Insulate a building from extreme temperatures, mainly by keeping the building interior cool in the summer." (Accessed online on October 25, 2006)
Installation is now underway on the largest living roof in California, a 2.5-acre expanse of native plants atop the new California Academy of Sciences building in Golden Gate Park. Hailed as the most complicated living roof ever constructed by architects and contractors alike, the roof features seven dramatic hills blanketed with nine species of native California plants for an estimated 1.7 million plants. This innovative roof, which creates a new link in the ecological corridor for wildlife, will make the new museum—both literally and figuratively—the greenest ever constructed. The plants will not require artificial irrigation, and will serve as a natural insulator and absorb rainwater, decreasing energy consumption and improving stormwater management. For more information, visit: http://www.calacademy.org/geninfo/newsroom/releases/2007/living_roof_fact_sheet.php (Accessed online April 25, 2008).
Why is this a Community Health Indicator?
Green roofs reduce storm-water runoff volumes, lower temperatures in urban environments, and reduce energy requirements for buildings (both by slowing heat transfer and by providing insulation).a Research shows that living in proximity to green space is associated with reduced self-reported health symptoms, better self-rated health, and higher scores on general health questionnaires.b Furthermore, the presence of views and access to forests, trees and other vegetation in the urban environment improves adult recovery from mental fatigue, leading to a reduction in socially unacceptable behavior and crime, as well as fewer behavior problems among children.c,d- DeNardo J, Jarrett AR, Manbeck HB, Beattie DJ, Berghage RD. Green roof mitigation of stormwater and energy usage. Paper number: 032305, 2003 ASAE Annual Meeting.
- Vries S, de Verheij RA, Groenewegen PP, Spreeuwenberg P. Natural environments - healthy environments? An exploratory analysis of the relationship between green space and health. Environment and Planning A. 2003(10);35:1717-1731.
- Kuo FE, Sullivan WC. Environment and crime in the inner city: does vegetation reduce crime? Environment and Behavior. 2001;33(3):343-367.
- Taylor AF, Kuo FE, Sullivan WC. Coping With ADD: The Surprising Connection to Green Play Settings. Environment and Behavior. 2001;33(1):54-77.