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About Eugene weekly. (Eugene, Oregon) 1993-current | View Entire Issue (March 10, 2011)
digs EW’ S HOME & GARDEN ISSUE GREEN ON TOP Great for the environment, wallet, health and wellbeing BY HEATHER CYRUS A &RPPXQLW\ 3DUWQHUVKLS %HQHÀW HAWTHORNE CONDOS IN PORTLAND (DESIGN BY JASON KING / ECOROOFS EVERYWHERE) PHOTO BY GREG HAINES “green roof” in Eugene doesn’t mean that there’s moss covering your house. Installing an actual green roof can increase urban green space and reduce negative impacts on air and water. A green roof, or ecoroof, is a living system that replaces a conventional roof and can be incorporated into new buildings or retrofi tted on existing ones. An ecoroof is a thin layer of vegetation growing in substrate of engineered soil on top of a waterproof membrane. In other words, you have plants growing on top of your house. Moss is not a green roof; it’s just wet and messy. According to Roxi Thoren, assistant professor in the departments of Architecture and Landscape Architecture at UO, green roofs provide environmental benefi ts including fi ltering air pollutants, absorbing carbon dioxide, providing habitat for pollinators, reducing the “heat island effect” in which built-up areas get hotter than rural areas, and decreasing stormwater runoff. Ecoroofs provide economic incentives as well. “There is some debate over the economic benefi ts, although it is generally accepted that a home or building will stay cooler in the summer with a green roof,” Thoren said. This translates to lower cooling costs. According to Thoren, the lifespan of a conventional roof ranges anywhere from 15 to 40 years, depending on climate and materials. A green roof may last 50 to100 years. “What usually breaks down a conventional roof is exposure to vast temperature changes,” Thoren said. Temperatures can change more than 60 degrees in one day on a roof, and the constant freezing and thawing creates an “expand and contract” motion that causes wear and tear. The green roof provides a layer of protection from this process. Finally, the aesthetic appeal alone convinces many to believe in the power of green roofs. “A living roof can raise property value in the same way that living by a park can,” said Thoren, who designed her current home with a green roof. Additionally, ecoroofs can be noise insulators to help drown out loud neighbors or traffi c. Thoren explains that green roofs are not composed of typical garden dirt; rather, they are made of engineered soil containing 75 percent pumice, 15 percent compost (organic material) and 10 percent sand. “It’s important to understand that a roof is a nonnative environment,” Thoren said. “Some native species, such as camas, do great because they are dormant in the hot 6KRSZLWKXVDWHLWKHUVWRUH 7+,6681'$< RIRXUWRWDOVDOHV ZLOOEHGRQDWHGWR 2OLYH6WUHHW :LOODPHWWH6WUHHW 0RQ6DW6XQ 18 MARCH 10, 2011 3+& VWULYHV WR LPSURYH DFFHVV WR VHUYLFHV DQG KRXVLQJIRUWKHKRPHOHVVLQRXUFRPPXQLW\ZLWKWKH KHOSRIORFDOEXVLQHVVHVQRQSUR¿WVDQGLQGLYLGXDOV EUGENE WEEKLY SURMHFWKRPHOHVVFRQQHFWFRP WWW.EUGENEWEEKLY.COM • BLOGS.EUGENEWEEKLY.COM
