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Living Roof at the California Academy of Sciences

  • Jeanne Price
  • “It's not often we get the opportunity to re-invent our public places,” commented Dr. Frank Almeda, Senior Curator of Botany at the California Academy of Sciences and spokesman for the Academy’s new building in Golden Gate Park and its remarkable living roof.

    While it is the first and largest living roof on a natural history museum, it is unique in three ways, Almeda told me. It has mounds which echo the city’s seven hills. Three of these hillocks house major structures and function as ceilings for the planetarium, the rain forest exhibit and the alligator swamp. The slopes draw cool air down at night over the central court or piazza to cool the interior. Skylights have heat sensors that open and close automatically letting in sunlight over the coral reef and rain forest.
    The entire roof is 4.5 acres of which 2.5 acres are planted with California natives.   Award winning architect of the project Renzo Piano of Italy describes his roof design: “like lifting up a piece of the park and putting a building under it.” Over one and a half million individual plants of nine species have been specially chosen to flourish in the park’s climate and grow and propagate with minimum care in the six inches of soil available on the roof. This roof will keep the building ten percent cooler than a standard one. Its plants will transform carbon dioxide into oxygen and reduce energy needs for both heating and cooling.
    The plants are set in biodegradable, porous trays made from tree sap and coconut husks that line the roof like tiles and enable roots to grow and interlock, linking them together to hold the soil in place on the slopes.
    The four species of perennials and five annual wildflowers making up the majority of the palette include strawberry (Fragaria chiloensis), self-heal (Prunella vulgaris), sea pink (Armeria maritima ssp. californica) and stonecrop (Sedum spathulifolium), as well as tidy tips (Layia platyglossa), goldfields (Lasthenia californica), minature lupine (Lupinus bicolor), California poppy (Eschscholzia californica) and California plantain (Plantago erecta). Almeda reported butterflies, insects, Goldfinches and Black Phoebes are already frequenting the roof, proving if you build it they will come.
    “No living system is maintenance free,” he noted. Unwanted plant species on the roof came in with the plants and on the planting trays. Weeds will continue to sprout on the roof and weeding will be constant and vigilant he predicted.
    Dr. Almeda has also been serving for the past two years as interim Director of Research at the Academy. His career with the Academy began in 1978 and he has been involved in the planning and construction of its new home since it all began ten years ago. At that time there was very little public interest in designing and building an environmentally sustainable building, he noted.   Today the world is beating a path to his door with requests for tours and information about the project. National Geographic and the English Discovery Channel are both filming programs for television. It is indeed the perfect time to put this building before the public with its message on sustainability. The grand opening is set for September 27, 2008.
    For public viewing there is a deck at the northwest corner of the building from which to admire the densest concentration of wildflowers in the city with its birds and insects. This terrace will have a perimeter garden of its own with more than 20 additional species of low-growing natives, Almeda explained.
    “This is probably the most complex building in the Bay Area,” he said. The roof, for instance, will absorb two million gallons of rainwater that would otherwise tax the city’s treatment plant. Surplus water from the roof is siphoned into an underground water table re-charge system and percolated into the park’s water table.
    The whole building sends a message on the possibilities for sustainability. Dr. Almeda reported the concrete, metal and green waste from the demolition of the old building was recycled. Over 80,000 tons of sand was recycled to other uses or returned to local dunes. The new building’s   wood was either recycled material or cut from a sustainable harvest. Its glass and steel were 100 percent recycled material. “The interior insulation is recycled blue jeans,” he mentioned with a chuckle.
    Frank Almeda will be speaking about the living roof on Thursday, April 3, at 7:30 p.m. at the Marin Art and Garden Center, 30 Sir Francis Drake Blvd., Ross   For information call 499-4204. The cost is $5. The event is sponsored by the UC Marin Master Gardeners.