Press Release

Stephanie Stone (415) 379-5121
Andrew Ng (415) 379-5123


Roof to feature 1.7 million native California plants and wildflowers
Museum is world’s largest public LEED Platinum certified building


Living Roof SAN FRANCISCO (June 7, 2007) — Installation is now underway on the largest living roof in California, a 2.5-acre expanse of native plants atop the new California Academy of Sciences building in Golden Gate Park. Hailed as the most complicated living roof ever constructed by architects and contractors alike, the roof features seven dramatic hills blanketed with nine species of native California plants. This innovative roof, which creates a new link in the ecological corridor for wildlife, will make the new museum—both literally and figuratively—the greenest ever constructed. Designed by Pritzker Prize winner Renzo Piano, the new building is expected to achieve a LEED Platinum certification and will stand as an embodiment of the Academy’s mission to explore, explain and protect the natural world.

During the initial search for a project architect in 2001, Renzo Piano’s sketch for an undulating living roof that integrated the new Academy more sensitively into Golden Gate Park and made nature a part of the building quickly won over Academy officials. His design was inspired by the concept of metaphorically lifting up a piece of the park and sliding the museum underneath. Only one difference would exist between the plants on the roof and the surrounding vegetation: the roof plants would all be native to the northern California coast. To select the species for the new Academy roof, Academy botanist Frank Almeda began working with a team of architects and living roof experts.

“Our goal was to choose native plants that were well adapted to the climate in Golden Gate Park and would provide much needed habitat for native birds, butterflies, and other beneficial insects,” explains Almeda. “We also needed to select species that would look attractive throughout the year, since a visually appealing roof is a much more powerful educational tool.”

Before the Academy’s original home in Golden Gate Park was torn down in 2004, Almeda and his team spent two years testing over 30 species of native plants in steeply sloped planter boxes on the roof, where they were left to grow without fertilization or irrigation. After surviving this trial, nine hardy finalists were chosen: four perennial plants that Almeda affectionately refers to as “The Fab Four” and five annual wildflowers. These nine species will attract a wide variety of native wildlife. Once installation is complete, the new Academy roof will offer the largest swath of native vegetation in San Francisco County.

The planted roof will also provide a number of other benefits. The iconic hills on the roof were designed not only for visual impact but also for energy conservation. Steep undulations in the roofline will roll over the Academy’s domed planetarium, rainforest, and aquarium exhibits, echoing the topography of the building’s setting and evoking the interdependence of biological and earth systems. These hills, which feature slopes in excess of 60 degrees, will draw cool air into the open piazza at the center of the building, naturally ventilating the surrounding exhibit spaces. Strategically placed skylights in the roof will automatically open and close to allow heat to escape through the tops of the domes. These skylights will also allow sunlight to reach the living rainforest and coral reef exhibits below, reducing the energy requirements for artificial lighting.

Padded with six inches of soil, the roof will provide excellent insulation, keeping interior temperatures about 10 degrees cooler than a standard roof and reducing low frequency noise by 40 decibels. It will also decrease the urban heat island effect, staying about 40 degrees cooler than a standard roof. Moreover, it will absorb about 98% of all storm water, preventing up to 3.6 million gallons of runoff from carrying pollutants into the ecosystem each year.

Innovative Installation
The new Academy’s living roof features much steeper slopes than any other living roof, so plant installation presents some challenges. The nursery that grew the plants for the Academy’s roof, Carmel-based Rana Creek, developed an innovative and sustainable strategy to prevent the plants and soil from sliding down these slopes. Using tree sap and coconut husk fiber, a waste product from coconut plants in the Philippines, they created porous, biodegradable trays in which to grow the Academy’s plants. Three inches deep and 17 inches square, these trays are installed onto the roof like tiles. Within a few weeks, the plants’ roots grow from one coconut husk tray into the next, locking the trays together into a tightly woven patchwork quilt of vegetation. A wide grid of rock gabions (wire mesh cages filled with rocks) provides additional support and creates walkways for future roof maintenance.

Installation of the new Academy living roof is now nearly half finished; once it is complete, the roof will hold 50,000 coconut husk trays filled with 1.7 million plants. The trays will slowly biodegrade over the next several years, leaving a well-established carpet of colorful plants and wildflowers.

Support for the Living Roof
The San Francisco-based Bernard Osher Foundation has made a $20 million donation to the new Academy project in support of the living roof and the four-story living rainforest exhibit. In honor of this generous gift, the Academy is pleased to announce the naming of The Osher Living Roof and The Osher Rainforest. “We are so grateful to the Oshers for their incredible generosity,” says the Academy’s senior aquatic biologist John McCosker. “Because of their support, the City of San Francisco will receive an invaluable gift – an architectural gem and unparalleled educational resource that will inspire millions of visitors to seek sustainable solutions in their own lives.”

About the New California Academy of Sciences
The new California Academy of Sciences will house the Kimball Natural History Museum, Steinhart Aquarium and Morrison Planetarium. The Academy conducts research in 11 fields of study, and is home to over 26 million scientific specimens. The new museum will open to the public on September 27, 2008. This major new initiative builds on the Academy’s distinguished 155-year history and deepens its commitment to advancing scientific literacy, engaging the public, and documenting and conserving Earth’s natural resources.