The ecology-minded Bay Area is catching up in the green-roof and green-wall movement.
THIS ARTICLE WAS PUBLISHED IN THE ‘Q’ – THE REGISTRY’S PRINT PUBLICATION – IN OCTOBER 2013
By Maria Shao[dropcap]I[/dropcap]n an era of heightened environmental consciousness, developers and building owners are looking to green roofs as a way to reduce their environmental imprint and meet rising requirements for low-impact development. Living roofs are being incorporated into structures to cool buildings, limit rainwater runoff and get people outdoors to expose them to natural habitats and sustainable architecture.
Other U.S. cities including Washington, D.C., Chicago and New York have installed green roofs at a faster clip than the Bay Area, according to Green Roofs for Healthy Cities Inc., a Toronto nonprofit. But regional examples are proliferating.[quote]“We see it as an amenity that becomes more valuable as cities require you divert rainwater,.” Chris Heimburger, vice president of development, Kilroy Realty Corp.[/quote]
“Every company is trying to leverage sustainable technology that will reduce their footprint. The green roof is another tool,” said Marlene Barneveld, branch manager in San Carlos for ValleyCrest Landscape Companies. “It’s also the social conscience of companies [and] the PR value of using the latest green technologies.”
The concept dates back to Mesopotamia, Greece, Rome and Persia. In Iceland, sod roofs have long insulated buildings from the cold. Germany is a leader in the technology.
In recent years, green roofs have cropped up in the United States. Ford Motor Co.’s River Rouge factory in Dearborn features a living roof. Chicago’s City Hall has one, and the city’s Millennium Park, atop a garage and train station, serves as one of the world’s largest green roofs.
Locally, one of the oldest living roofs, an expanse of prairie vegetation, was installed in 1997 on the former Gap Inc. headquarters in San Bruno, now occupied by Google’s YouTube. San Francisco’s most renowned green roof was installed in 2007 atop the newly built California Academy of Sciences in Golden Gate Park. Since then, green roofs have appeared on a San Francisco city government office building and a public library in its Sunset district; at low-income apartment buildings in San Jose and a Berkeley animal shelter; at a family home in Marin County and some private schools. In late August, the U.S. General Services Administration unveiled a 14,000 square foot green roof at its new regional headquarters at 50 U.N. Plaza in San Francisco.
More green roofs are planned for high-profile future construction: the 5.4-acre park atop San Francisco’s Transbay Transit Center that will be ready in 2017; Facebook’s West Campus headquarters building in Menlo Park where it proposes an eight-acre green roof; and the top of the nine-story suite tower at the San Francisco 49ers Levi’s Stadium.
“The green roof is a way to make the building more sustainable, whether you’re trying to get a LEED rating, return on investment or be environmentally conscious,” said John Loomis, principal at SWA Group, which did the landscape design of the Academy of Sciences’ living roof.
Commercial developers are taking note. Kilroy Realty Corp. plans a six-story LEED Platinum office building at 333 Brannan St. in San Francisco that will have at least a 3,000-square-foot vegetated area as part of the 30,000-square-foot roof. Native, drought-tolerant plants will live in 12 inches to 15 inches of growing medium. Excess rainwater from the roof will drain into a tank onsite, where it will be treated and pumped back up to flush toilets. The vegetated area will be adjacent to a roof deck, where occupants can enjoy a verdant view. The greenery will add some insulation value to the roof.
The green portion will cost $40 to $50 a square foot compared to $10 a foot to $12 a foot for a conventional roof, and it probably won’t mean higher rents. “We see it as an amenity that becomes more valuable as cities require you divert rainwater,” said Chris Heimburger, Kilroy vice president of development.
Photography by Laura Kudritzki