Living Proof
A growing design trend with big environmental benefits, green roofs
are sprouting up from coast to coast
From Toronto to Tampa, and from New York to San Francisco, green roofs are blooming in every region in North America. A visit to the top of the University of Texas (UT) Health Science Center in Houston provides an impressive introduction to green roofs and their ability to shield buildings from heat and cold while also reducing energy usage.
“You can see our green roof on Google Earth,” exclaims Dr. Carl Hacker, referring to the Web search engine’s satellite-imaging system. Hacker, an associate professor at the UT Health Science Center, designed the roof, which was installed in 2005 and now serves as an outdoor classroom where students can observe nature’s services at work for the environment.
Green roofs suddenly are the buzz, as a proliferation of planted rooftops is taking root across the United States. It’s an important trend both aesthetically and environmentally. How do green roofs help the environment? They reduce storm water runoff and airborne pollutants, and lower energy costs by insulating against the cold and shielding against the sun’s heat. Most are made using low-maintenance, lightweight vegetation — native grasses, flowers, mosses, and succulents — and, of course, that adds compelling visual appeal.
But green roofs aren’t all the same. As the trend has spread, they’re proving to be as distinct in size, appearance, and function as the buildings they occupy and the cities they enhance.
A Movement Takes Root
The green roof movement started in Germany in the 1960s — it’s estimated that 10 percent of all the flat roofs in that country are now green — and many European countries have joined the wave. But the United States, too, is making headway, and Canada is following suit. According to Green Roofs for Healthy Cities, a Toronto-based advocacy group, over two million square feet of vegetation were added to green roofs in North America between 2006 and 2007.
Although the United States has been slow to embrace green roofs on a large scale, one of the first large projects to attract international attention was completed by Ford Motor Co. in 2000. As part of a revitalization plan, architect and early advocate of green roofs William McDonough designed an enormous green roof — 10 acres in area — to cover Ford’s historic 1928 River Rouge industrial complex, in Dearborn, Mich. It’s still the world’s largest green roof, according to Guinness World Records.
McDonough was already a pioneer in 1997, when he showed that green roofs can be integrated into a building’s architecture and need not be flat. His design for the Gap’s corporate campus in San Bruno, Calif., included an undulating roof of native grasses and wildflowers. Meant to signify a connection to the area’s coastal ecosystem, the roof was one of the earliest examples of a corporation using its headquarters to promote sustainability in general. Insert photo (spot final) to the right of this paragraph with the text wrapping around the image accordingly.
“Today we try to incorporate green roofs into all our projects,” says Roger Schickedantz, a director at McDonough + Partners and the project manager for the Ford River Rouge plant. “We’re learning that there are many ways to make green roofs. For instance, we’re designing ‘healing gardens’ for the new University of California San Francisco Medical Center at Mission Bay. Three unique terraces will serve the different specialties, which include maternity, pediatric, and cancer treatment services.” The gardens will perform the same ecological function as any green roof, but they will also function as “parks in the air,” one of the latest trends in habitable green roofs.
A Sustainable Wave
Another green roof is already making waves in San Francisco, at the new California Academy of Sciences facility in Golden Gate Park. The academy bills itself as the world’s greenest museum, and the 2.5-acre rooftop ripples with hills and valleys, creating a metaphor for San Francisco’s famous topography. Interlocking biodegradable trays hold 1.7 million plants securely to the slopes, and an open-air observation terrace lets visitors take a close-up look at the roof’s blooming vegetation and watch the birds, butterflies, and insects.
Green roofs also are playing a part in the transformation of dormant industrial areas into viable mixed-use neighborhoods. In 2002, the New York–based design firm Balmori Associates saw just such an opportunity in Long Island City, an evolving industrial area in Queens, just across the East River from Manhattan.
“We chose Silvercup Studios because it had an expanse of available flat roofs,” recalls Balmori director Mark Thomann, who approached Silvercup, a television and film production facility, as he would any design project, in this case, using variegated colors and patterns. “We selected 20 different sedum varieties and organized the different hues and textures into rows, which make up a larger geometric grid,” he explains. As the sedum plants bloom from spring through fall, they create an ever-changing riot of yellows, reds, and pinks. By creating an array that’s visually alluring, the designers infused an ecological endeavor with a visual appeal to enliven the gritty district.
Classic Meets Cutting-Edge
Green roofs can also enhance historic structures as well as industrial buildings. The Cleveland Environmental Center, which occupies a landmark 1918 bank building, integrates native vegetation with a solar array and a patio on its 5,000-square-foot rooftop. The project, Ohio’s first green commercial retrofit, merges cutting-edge environmental design and historic renovation, demonstrating the cost-effectiveness of going green.
The cachet that a green roof can bring to a project has not been lost on the resort and hospitality industries. When the Mount Washington Resort in Bretton Woods, N.H., began a $50 million renovation and spa addition, one of the priorities was the construction of a habitable green roof on top of a new wing. The owners even gave it a name, Jewell Terrace. They realized that an outdoor venue situated in full view of New England’s magnificent mountain ranges would not only provide a space for social events, but would also add value by publicly demonstrating the resort’s commitment to stewardship of the region’s sensitive ecosystem. Mount Washington Resorts is part of the next generation of green-roof strategies. By demonstrating that they add value and distinction, projects like this have made green roofs officially mainstream.
They’re proving to be durable too. The asphalt, concrete, and synthetic membranes that cover our cities’ surfaces are designed to last, but the green roof of the UT Health Science Center held its own last September, when Hurricane Ike’s 110-mile-per-hour winds roared through Galveston and Houston. The storm ripped off roofs and blew out windows, and after it passed, Carl Hacker went up to the center’s roof to survey the expected damage. “There wasn’t any, really,” he says with pride and relief. “All the plantings held their ground.”
— Sara Hart
Illustrations: Matt Vincent
