November 1, 2005

Green roof grows in recycled carpet

Photo by Dipika Kohli Swedish expert Louise Lundberg (kneeling) talks with David Gold. She inspired him to build a green roof in Portland. Yesterday they were both in Seattle, where pieces of his roof were on display.

Portland building owner David Gold was in Seattle yesterday to tell people how plants can grow on roofs, even in carpet.

About 200 architects and city officials gathered at Seattle Central Library for a seminar on green roofs. Gold spoke, along with Drew Gangnes of the structural engineering firm Magnusson Klemencic Associates and Louise Lundberg of the Scandinavian Green Roof Institute.

International Sustainable Solutions organized yesterday's event, as well as tours to Scandinavia that first got Gold and Gangnes thinking about how to make green roofs work in Seattle.

Seeing examples of real-life green roofs convinced Gangnes to spread the word by setting up small roof plots in Seattle. "People's attitudes change by being able to kick the tires," he said.

Gangnes has been testing 8-foot by 10-foot plots on several sites in the city to see how much water they hold. About 500 plants are in each plot, which range from two to eight inches in soil thickness.

He is looking at how much water a green roof absorbs to see whether the size of runoff collection systems can be reduced and save money.

Birds uprooted some of his plants and an unusually dry year also hindered his data gathering. But he is continuing this effort because he knows the numbers would help developers justify the initial cost. "For most developers, life-cycle costs don't mean a hill of beans."

Gold said on his Scandinavian tour he learned from Lundberg how easy green roof installation could be. He surprised himself by promising the tour group he'd put one on his own building.

Earlier this summer, Gold covered his 600-square-foot roof on Cathedral Park Place in Portland with panels of recycled carpet that hold dirt and plants. Using carpeting makes the green roof easier to transport, so Gold brought three of the panels to Seattle. They were on the Reedo Building as part of a tour following yesterday's presentations. Gregory Broderick Smith Real Estate is redeveloping the Reedo.

Gold said he thought carpet would work just as well as a European product that was much more expensive. So far, he said, it has.

Lundberg inspired him to try it, he said, and yesterday she praised him for taking the initiative.

A group of architects gathered around Gold's square plot, asking how much the material weighed and what kinds of soils and plants he used.