Board of Supervisors Unanimously Approves Supervisor Wiener’s Groundbreaking Green Roofs Legislation
Legislation will add green roofs, also known as living roofs, as an option to meet existing solar mandate requirement, making San Francisco the first city in the country with a green roof requirement
San Francisco — Today the Board of Supervisors unanimously approved Supervisor Scott Wiener’s legislation to create the country’s most comprehensive green roofs requirement. This legislation, which along with Supervisor Wiener’s previous solar roofs ordinance, creates a broad Better Roofs Program for new developments in San Francisco.
The new legislation builds on the existing solar requirement authored by Supervisor Wiener, which requires that at least 15% of new roofs in buildings up to 10 stories in height must have solar installed. The green roof option will allow developers to replace solar with green roof at a rate of 2 square feet of green roofs for every 1 square foot of solar. That means that instead of doing 15% of the roof area at solar, developers can do 30% of the roof area as green roofs, or, more likely a combination of the two.
“Green roofs are a major tool in our fight against climate change and to improve sustainability,” said Supervisor Wiener. “Our rooftops are a largely untapped resource that we need to put to work in our dense urban environment. Green roofs will make our air cleaner, our buildings more energy efficient, and our environment healthier. I’m proud that we are continuing to advance aggressive and innovative solutions to fight climate change in San Francisco and serve as a model for the entire country.”
The new addition of green roofs to this requirement will make San Francisco the first city in the country to implement this regulation. France has advanced similar requirements that will go into effect in 2017. With the passage of this legislation, between 15% and 30% of roof space on most new construction will incorporate solar, green roofs, or a blend of both. This legislation was recommended by the Planning Commission, the Commission on the Environment, the Building Inspection Commission, and SPUR.
Examples of existing green roofs in San Francisco include on the California Academy of Sciences in Golden Park, a mixed-use residential building at 38 Dolores Street, and 50 United Nations Plaza. The benefits of green roofs are numerous. They include:
- Reduced quantity of stormwater runoff and improved water quality of the runoff
- Reduction of the urban heat island effect (when built up areas are hotter than surrounding rural areas)
- Improved air quality
- Building energy efficiency and energy savings
- Open space for passive recreation
- Aesthetic improvements
- Noise reduction
- Increase in habitat that promotes biodiversity
- Extended life of the roof
Under existing state law, California’s Title 24 Energy Standards require 15% of roof area on new small and mid-sized buildings to be “solar ready,” which means the roof is unshaded by the proposed building itself, and free of obtrusions. This state law applies to all new residential and commercial buildings of 10 floors or less. Supervisor Wiener’s solar ordinance built on this state law by requiring this 15% of “solar ready” roof area to have solar actually installed. Now, with the green roofs component in place, developers can do 15% solar or 30% green roofs, or somewhere in between.