Although leaves, twigs and even seedlings are usually cleared from roofs and gutters, landscape architecture students at Kansas State University have drawn up plans to plant entire landscapes up there.
There are challenges to creating "green roofs" in communities without them, but the potential is great, according to Lee Skabelund, assistant professor of landscape architecture. A layer of light-weight planting medium and vegetation can reduce heating and cooling costs while slowing the runoff of rainwater that would otherwise burden storm-sewer networks.
A city topped with greenery instead of conventional bitumen can improve air quality while reducing the overheating that built-up areas suffer in the summer. Skabelund also cited the benefits of longer roof life, resistance to fire and the blockage of telecommunication radiation.
Twelve fourth-year landscape architecture students in K-State's College of Architecture, Planning and Design came up with proposals to put green roofs on several campus buildings
Some architecture firms have made a specialty of green-roofing, including BNIM Architects in Kansas City, Mo. Installations like that atop Chicago's City Hall, the GAP complex near San Francisco's airport and the headquarters of the American Society of Landscape Architects in Washington, D.C., have raised the technique's profile.
"I think it's something we need to seriously look into on campus, because of its potential to save energy and reduce runoff," said Tom Rawson, K-State vice president for administration and finance.
But facilities managers can be wary, and not just because of higher initial costs. The multiple layers of root-proof membranes and earth-retaining matrices are foreign territory, and maintenance demands are another unknown.
Tim Duggan, a K-State landscape architecture alum who works for BNIM, urged students after their presentations to emphasize not the overall costs, but rather the difference in cost over a conventional roof, and how that might be offset by potential savings and social benefits. He was one of several professionals and faculty who reviewed the designs.
To complement the work of landscape architecture faculty and students this past year at the K-State International Student Center’s rain garden, Skabelund and Duggan would like to see a green roof demonstration completed during spring 2008.
Stacy Hutchinson, associate professor of biological and agricultural engineering, and other K-State faculty support such a project, Skabelund said. Hutchinson already is monitoring temperatures and water use for green-roof-like plantings in the Seaton Hall alley.