Cities are facing climate change. Urban areas are warming up. Storm water overflow is contaminating San Diego's beaches, bays and rivers. Development continues to encroach on the natural environment.
Green roofs (or "eco-roofs") provide a simple, practical solution to all these problems. San Diego's first commercial green roof was planted in March at Good Earth Plant Co. in Kearny Mesa. So far, the 1,700-square-foot demonstration garden is thriving in the midst of an industrial sea of blacktop and sheet metal.
Jim Mumford, CLP, president of Good Earth Plant Co., says it's a natural extension of his original business, which brought nature indoors. "Green roofs are successfully improving the environment and providing benefits for businesses and homes around the world. Why can't we bring this technology to San Diego and make them successful here?" said Mumford.
Green roofs are an engineered, lightweight roofing system that supports plants. Green roof technology is popular in Europe, and used in some North American cities including New York, Chicago, Toronto and Portland. But green roof technology is not well known in most of the United States.
Green roofs offer a number of benefits both to the environment, and to the businesses and residences that install them. Green roofs can:
¥ Prevent water pollution;
¥ Lower energy use;
¥ Lower ambient air temperatures, combating the urban heat island effect;
¥ Clean the air and add oxygen;
¥ Mitigate the loss of environment; and
¥ Extend the lifespan of the roof by two-three times.
Mumford is using his own business as the prototype project. The objectives for his green roof project include conducting a performance evaluation of plants, soil and irrigation. He will record rooftop temperature and stormwater runoff. All aspects will help yield a cost-benefit analysis, which Mumford hopes will prove green roofs are cost-effective for most homes and businesses.
"We have to start getting serious about ways to improve our environment and reverse some of the damage we've done," said Mumford. "When you have children like I do, you start thinking about what we're going to leave behind for the next generation. I'm excited about creating this project and driving the market for green roof technology in San Diego."
Green roofs can consist of any appropriate type of plants from flowers to vegetables. Mumford has chosen regional native plants for lower water use and maximum environmental benefits, including succulents, grasses, bulbs and perennials that include alliums, primroses and asters among others.
Mumford also constructed a modular-style green roof on a second building. It uses large flat containers that sit in a grid to provide the growing platform for the plants. Mumford has chosen primarily varieties of sedums. They are a staple among green roofs and provide quick coverage. However, the drawback is that they require watering. As a green roof is geared toward sustainable architecture, water use needs to be kept to a minimum.
Mumford said about a third of the plants are thriving four months after planting. Another third are doing as expected, and the remaining third aren't growing as anticipated.
As San Diego's designated green roof champion, Mumford is putting together a committee to influence public policy and incentives including subsidies, rebates, accelerated permitting and density bonuses. He recently met with Gov. Arnold Schwarzenegger's legislative staff for the environment to advocate for green roof incentives including support of the Sustainable Building Act of 2007, and amending California's Title 24 Building Energy Efficiency Code to specifically include green roofs as a cool roof performance option.
For additional information, visit www.greenroofsandiego.com.