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Issue link: https://read.dmtmag.com/i/144453
Green Roofs By Maryanne Welton Green Roof Project Profile San Jose, California's first green roof is setting the standard high with community housing development eplacing an aging residential hotel near downtown San Jose, Calif., Casa Feliz Studios was developed in 2009 with 60 new apartments by First Community Housing (FCH). The energy-efficient apartments serve extremely low-income residents — 35 percent with developmental disabilities — and are located in a run-down neighborhood of Victorian houses interspersed with deteriorating 1960s apartment buildings. At less than half an acre, the tight infill site required a creative and efficient design. The building's crowning glory is San Jose's first green roof, which was engineered to maximize stormwater retention, holding 60 to 80 percent of rainwater on the roof. Preliminary meetings with the city public works department realized a requirement to replace and upgrade the existing storm sewer to a 100-year-flood capacity at an estimated cost of more than $300,000. The owner and architect, Rob Wellington Quigley, FAIA, researched using a green roof as a way to mitigate the stormwater requirement. Paul Kephart of Rana Creek provided FCH with design as- R sistance using this "revised" technology. Preliminary analysis showed that the installation of a green roof could reduce the stormwater runoff to such an extent that only a new 10-year-event pipe would be required. This could be accomplished at the same cost or less than the 100-yearstorm sewer "upgrade." A series of meetings with various city departments was necessary to convince city officials that the green roof could indeed reduce the building's stormwater runoff. The high cost of upgrading the insufficient storm drain system made the decision to add green roofs economically feasible, but the green roofs add much more to the building than simple stormwater retention. They provide habitat for wildlife, increased roof insulation and cooling, longer roof life due to the blocking of ultraviolet rays, and reduced ambient heat reflected from the roof (which increases the efficiency of the photovoltaic system). The non-irrigated plantings bloom during the mild winter and spring rain, and die down during the long, warm summers. The use of organically grown plants and a pesticide-free growing medium protects the quality of any water that percolates into the site or drains into the public storm drain system. The plants are a mixture of annual and perennial sedums, grasses and wildflower species that provide a healthy habitat for birds, insects and butterflies. The plant materials were chosen to thrive in hot, polluted air and shallow soil TEAM OWNER/DEVELOPER: First Community Housing ARCHITECT: Rob Quigley Architects, FAIA GENERAL CONTRACTOR: Branagh Construction LEED CONSULTANT: Simon & Associates GREEN ROOF CONSULTANT: Rana Creek CIVIL ENGINEER: Carroll Engineering ROOFING: Tremco MODULAR GREEN ROOF SYSTEM: BioTray GREEN ROOF MONITORING: Agilewaves PLANT LIST BIOTRAYS Sedum 'album murale' Sedum rubrotinctum 'Jelly Bean' Sedum 'acre aureum' Sedum 'Borshi Sport' Sedum spathufolium Dudleya ceaspitosa (or) pulverulente TOP LEVEL ROOFS (HAND-SCATTERED SEED) Lasthenia californica Eschscholzia californica Lupinus nanus Gilia capatata Clarkia amoena Trifolium wildenovii Castilleja exserta Plantago erecta Layia platyglossa 8 Landscape and Irrigation July/August 2013 www.landscapeirrigation.com