Gunderson unveils second 'habitat' ecoroof
By Drew Dakessian, Sustainable Business Oregon intern
Portland City Commissioner Dan Slatzman cut the ribbon on Gunderson's latest habitat roof project. Click on the image for a closer look at the habitat roof.
Dignitaries this week dedicated a 2,400-square-foot ecoroof at the Gunderson LLC facility on Northwest Front Avenue in Portland, continuing the company’s efforts to gauge such a roof’s habitat value.
City Commissioner Dan Saltzman and Mark Eitzen, general manager of Gunderson, a division of Lake Oswego-based The Greenbrier Cos. Inc., cut the ribbon on the second of three so-called habitat roofs that the company will erect, providing a home for wildlife in an industrial zone.
Habitat roofs are based on the model for a traditional ecoroof, defined by Portland Bureau of Environmental Services as “a lightweight vegetated roof system used in place of a conventional roof … typically made of a waterproof membrane, drainage material, a lightweight layer of soil, and a cover of plants.”
In Gunderson's case that roof features 30 types of plants that bloom throughout the year serving as fodder for a roof-based micro-ecosystem.
“Ultimately, you’re trying to have a food source for birds,” said David Harvey, Gunderson’s director of health and safety. “Basically, you plant the plants to establish a food chain, and the plants then become home to small insects. What ends up happening is the spiders eat the insects, the wasps eat the spiders, and the birds eat the spiders and the wasps.”
If a habitat roof is viable, “a bird hardly knows if there’s manufacturing down there or if it’s just regular ground,” Harvey said.
Gunderson became the first company in the Northwest to work on such a project in an industrial setting with an initial habitat roof completed in June of last year.
After experimenting with different kinds of soil on the first roof, Gunderson determined that engineered soil, a blend of organic and inorganic matter primarily provided by Phillips Soil Products in Canby, Ore., is most viable.
“We’re trying to maximize the habitat value in a cost-effective way,” Harvey said. “We use engineered soil because the regular soil weighs about 50 percent more than the engineered soil does. By using the lighter, engineered soil, we can afford to convert more of an existing roof for the same amount of money.”
The second roof will test soil depth, with one end of the roof roughly two inches deep and the other about five.
The results of this test will pave the way for a third roof, which will be the first to convert an existing structure, on a portion of the 900,000 square feet of existing roof area at the site.
“The lighter it is, the easier it would be to convert an existing roof, because we don’t have to reinforce the roof as much,” said Harvey.
According to city officials, installation costs for ecoroofs in Portland range from $5 to $20 per square foot.
Gunderson has been paying employees to build and furnish the habitat roofs.
“From our perspective, it’s the right thing to do,” said Harvey. “We feel like the industry and the environment can coexist, and we’re trying to prove that can actually happen.”
Currently, Portand's ecoroof incentive program offers up to $5 per square foot for an approved ecoroof project, as part of the city’s Grey to Green initiative launched in 2008.
As of last May, Portland had 288 ecoroofs covering nearly 14 acres. The city's goal is to have 43 acres of ecoroof coverage by 2013.
Harvey anticipates that ecoroof adoption will increase with a burgeoning emphasis on corporate sustainability and additional government incentives or mandates. Gunderson plans to offer the results of its habitat roof experimentation to improve future ecoroof developments.
Gunderson is a producer of marine barges and is an active participant in the Working Waterfront Coalition, an organization of businesses concerned about the environmental health and economic vitality of the Portland harbor.
It is also awaiting approval for Ambre Energy's Morrow Pacific coal export project, which would bring a $55 million barge-building contract to Gunderson.
Harvey said he didn't think Gunderson's habitat roof project is at odds with the company's construction of coal barges.
“From my perspective, the barging of coal for a coal export facility is an environmentally responsible form of transportation,” said Harvey. “It doesn’t have congestion, and it avoids coal dust.”
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