Forget green roofs - this whole building lives

Rana Creek founder Paul Kephart

Rana Creek Business: Green architecture Location: Carmel Valley, Calif. Employees: 42 2008 Revenues: $6.5 million

CARMEL VALLEY, Calif. (Fortune Small Business ) -- There aren't many cutting-edge urban architecture firms in Carmel Valley, Calif., a placid expanse of gnarled oak trees and steep, grassy hills about 120 miles south of San Francisco. But this is where you'll find Rana Creek, a 14-year-old, $6.5 million company that converts city buildings into countryscapes.

Last year Rana Creek founder Paul Kephart put together an audacious plant-covered roof for the new California Academy of Sciences, in San Francisco's Golden Gate Park. Green roofs are becoming commonplace across the U.S., but no others yet have hills.

Now Rana Creek hopes to bring the country to San Francisco in its boldest project yet. Pending a city permit, ground will be broken on the first commercial structure in the U.S. with "living walls." The 10-story building, 110 Embarcadero, will have plants growing out of the spaces between floors on the building's glass exterior. Vines will snake around vertical and horizontal trellises on three sides of the building.

Kephart, 53, knew how to sell the project. "You never tell a developer, 'Together we'll save the world,' " he says. "You tell him, 'We'll build a highly resource-efficient building, save you money ... and together we can save the world.' "

The living walls will be integrated with the building's irrigation system. Their soil will filter gray water from sink and shower drains so that it can be reused. Along with a green roof, the living walls will absorb an estimated 70% of the rain that falls on the building, capturing pollutants and keeping them out of the city's storm drains. Rana Creek says the walls will reduce water usage by 66%.

The company also estimates 110 Embarcadero will use 67% less energy. In summer, living walls can keep a building 20 degrees cooler inside than it would otherwise be. In winter, the vines will thin out, allowing more of the sun's rays to enter the building.

The building's developer, Hines, won't reveal its budget but admits that the company is taking a risk on an "expensive" project. Says Hines senior vice president Paul Paradis: "San Francisco tenants will pay a little extra to be in a building this responsible."

Kephart has excited his peers, at least.

"There are some beautiful green walls in Europe, but they don't serve a purpose," says Kevin Burke, director of practice at William McDonough + Partners, a leading sustainable architecture firm. "Paul is saying, 'How can we integrate that into the metabolism of a building? Can it serve a function?' That's what intrigues us."