Green roofs on the rise

Last week, California Academy of Sciences contractors began planting native California plants and wildflowers on a 2.5-acre undulating rooftop in Golden Gate Park in San Francisco. The living roof will adorn the newly renovated museum, which is also seeking LEED (Leadership in Energy and Environmental Design) Platinum certification. Designed by Renzo Piano, construction of the new facility began in September of 2005, and the museum expects to move exhibits and animals back to Golden Gate Park from its temporary location to reopen in October of 2008. According to the Academy, the new living roof will reduce storm water runoff by up to 2 million gallons of water per year and produce over 5 percent of the museum’s annual energy needs using rooftop solar cells.

While garden-covered rooftops possibly date back to the Hanging Gardens of Babylon, maximizing a rooftop’s potential for capturing solar energy and rainwater and cooling buildings is gaining popularity as a high-potential solution for addressing global warming and preventing runoff pollution. It has been widely demonstrated that green roofs, also called living roofs, improve air quality, conserve energy, reduce stormwater runoff, cool buildings, and lessen the urban heat island effect. For over a hundred years, sod and plant covered roofs have been popular in Europe, especially in Scandinavian countries. The city of Chicago is one of the country’s leaders in green roof projects.

For the San Francisco Bay Area, the Bay Localize web site is a good hub for information on green roof resources. The Oakland-based nonprofit is studying ways to create living roofs on a variety of building types by assessing the feasibility, including load-bearing capacity, and benefits of rooftops replete with food gardens, solar panels, and rainwater catchment systems.

And on Saturday, June 23 from 10:00am to 1:00pm, the San Francisco Botanical Garden Society is hosting a “Living Roof Demonstration and Workshop” taught by Brent Bucknam of Rana Creek, a living roof ecological design firm for the California Academy of Sciences.