UWM will begin putting a green roof on the top of Sandburg Hall Commons this summer.

Construction is pegged to begin on an environmentally-sound green roof for the University of Wisconsin-Milwaukee Sandburg Hall Commons, a UWM administrator said.

“Bids will go out as soon as we get authority from the state,” said Scott Peak, the director of University Housing. “But we“d like to start as soon as the students leave for the summer.”

Sandburg Hall Commons includes the area between the four resident hall towers and, if the project goes through, its roof would serve as more than a shelter overhead.

The roof will be planted with a groundcover. Seedum, a native plant, was chosen for its shallow root structure and will soak up water like a sponge, said James Wasley, an associate professor in the Department of Architecture and Urban Planning.

Green roofs are useful in controlling storm water run-off, Wasley said. The goal, he said, is to keep the water on the roof or at least slow it down.

The Sandburg Commons green roof is part of the “Stormwater Masterplan for the UWM Campus.”

The plan was developed in 2002 with a grant from the Milwaukee Metropolitan Sewage District. The goal of the plan is for UWM to be a zero-discharge zone.

That means, Wasley said, the run-off from campus would be equivalent to the run-off rate before the land was developed, as if it were still a prairie or woods.

“The problem with storm water is that run-off can be as polluted as sewer overflow,” said Bill Graffin, the public information manager for the Milwaukee Metropolitan Sewage District.

Run-off from UWM is treated. UWM is part of a combined sewer district, where storm water and human waste are combined in a single pipe. This is good and bad, Wasley said.

It“s good that the storm water is treated before entering Lake Michigan, but rushing storm water can overwhelm the combined system, causing overflows or backups into basements, Wasley said.

Besides converting the Sandburg Hall Commons roof to a green roof, the plan looks to transform all appropriate flat roofs on campus to green roofs. That would include the Klotsche Center, the Union and Golda Meir Library. The plan also called for rain gardens and parking lot changes to manage storm water flow.

The Sandburg Commons is an attractive first step because of its visibility, said Wasley. While the green roof will not be designed to allow public access, Wasley said he hopes a student design contest will result in an artistic planting pattern.

Students will also be involved in research. The elevated part of the roof will be divided in half, with half being converted to a green roof and half left as tar and gravel. Wasley envisions engineering students comparing actual water flow reduction and biology students testing to determine if the plants will help filter pollutants out of the water.

Wasley said the roof should not need ongoing maintenance once the plants are established. He said studies indicate that the green roof should actually have a longer lifespan than a more typical tar and gravel roof. A typical roof can reach 140 degrees in the summer which contributes to the degradation of the roofing materials. The foliage and aggregate should keep the green roof in the 80-to-90 degree range.

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