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Seattle’s Rooftops Turning Green

Half of new commercial structures here are now designed with planted rooftops

The Emerald City is living up to its name, according to a new study which found that half of all new commercial structures here are designed with planted rooftops. With 62 green roofs already built—359,375 square feet, about the size of nine football fields—Seattle is a national leader in the field.

The report found that the rate of new green roof installation has increased nearly every year in Seattle since 2001 and the design and installation business sector has also consistently expanded during this time.

The study also created the first self-guided walking tour of green roofs in North America, which will allow residents and visitors to explore the hidden gems of our urban ecosystem.

“Our city has established itself as a national leader in green roofs,” said City Councilmember Mike O’Brien, chair of the Council’s Seattle Public Utilities and Neighborhoods Committee. “The adoption of green roof technology by developers will further solidify Seattle’s position as a national leader in green stormwater infrastructure.”

“Green roofs can lead directly to reduced utility rates for stormwater, an increase in property values, energy efficiency benefits for buildings and opportunities for urban agriculture in existing ‘food deserts,’” O’Brien said. “Green roofs are a component of Seattle’s green stormwater infrastructure strategy because of their ability to slow stormwater flows and cleanse runoff in higher density neighborhoods.”

Among the green roofs inventoried in the report, four were identified that are integrating food production into their systems. An example is the Bastille Café in Ballard, which uses rooftop-grown produce in several dishes. At M-Street Apartments on First Hill, residents can tend to their crops in a “P-Patch” style garden after walking their pets at the rooftop dog park.

One major contributor to the growth of green roofs since 2006 has been the Seattle Green Factor landscaping requirement.

Green Factor is a scoring system that encourages developers to consider green roofs, vegetated walls, and rain gardens in addition to conventional landscape features. Recent changes to the City’s Stormwater Code, which is weighted toward “green stormwater infrastructure” practices including green roofs, are also expected to factor in future growth of the green roof sector here.

Green roofs also provide credits for LEED and Built Green Programs. In 2011, SPU will evaluate inclusion of a green roof incentive for larger roofs within target neighborhoods in the Rainwise Program. In addition, green roofs, when in combination with cisterns or rain gardens can help achieve the City’s Combined Sewer Overflow (CSO) reduction goals.

The full report — Green Roofs in Seattle: a Survey of Vegetated Roofs and Rooftop Gardens is the result of a partnership between City of Seattle and the University of Washington Green Futures Lab.

The self-guided tour of green roofs in Seattle provides an easily printable one-page map, locals and tourists alike will now be able to explore and view over 20 green roofs and lids throughout the City, a great free way to spend a day and enjoy some of the City’s finest views.