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 at least 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, a collaboration between SPU, DPD, and UW, 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 includes a self-guided green roof walking tour, which will allow residents and visitors to explore the hidden gems of our urban ecosystem.
“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,’” said City Councilmember Mike O’Brien. “Green roofs are a component of Seattle’s green stormwater infrastructure strategy because of their ability to slow stormwater flows 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 development standard that encourages use of green roofs, vegetated walls, and rain gardens in addition to conventional landscape features. Recent changes to the City’s Stormwater Code, 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. For more information of the City’s CSO Reduction Strategy see www.seattle.gov/util/cso.
The report, inventory, and walking tour map are available at: www.seattle.gov/dpd/GreenBuilding/Resources/TechnicalBriefs/