UW News

April 1, 2010

Up on the roof: A very green pilot project at the Botany Greenhouse

UW News

The Botany Greenhouse is aiming to show the campus how it can get even greener, not with plants inside, but on top, with a living “green” roof on a shed alongside the greenhouse proper.

“We’re building this green roof in order to demonstrate to the campus community what green roof technology looks like,” said Danielle Pierce, a staff researcher with the Department of Landscape Architecture. She’s also with the Green Futures lab, which seeks faculty and student-driven solutions related to urban ecological planning. “It’s just a demonstration project, on a roof that’s 47 by 12 feet.”

Work was under way even as Pierce described the project, which has come together recently, and rather quickly. The green roof project is the result of work and agreement from several campus areas. Involved are the Department of Biology and the College of Arts and Sciences, the College of Built Environments and its department of Landscape Architecture. Doing much of the manual work were apprentices with the Seattle local of the Roofers and Waterproofers Union.

“I’m really excited about this, and I’m struck by how beautifully these different departments and sectors on campus integrate on this type of project,” said Doug Ewing, manager of the Botany Greenhouse. He also thanked Facilities Services for its assistance and permission. “It’s just all kind of coming together,” he said.

The shed has a corrugated steel roof on which was added a protective plywood deck and a layer of water-resistant EPDM (ethylene propylene dilene monomer) rubber as a sealant. Concrete squares are used as borders and a railing has been added for safety.

On top of the protective layer are plastic trays, 4 inches and 8 inches deep in different parts, that will host the plants to make the green roof. Pierce said, “They drain slowly so they retain rainwater for a certain period of time and keep it around so the plants can use it, and then it slowly drips away.”

One of the three areas of trays was filled Tuesday with sedum, a leaf succulent often used as ground cover. The center area will be planted and maintained by the UW Farm program, with various edible plants and vegetables; and the third portion will be plants native to the region. “We’re going to be putting in native plants as a sort of experiment,” Pierce said. “We’re going to grid it off and map out where each one grows, so we know who’s alive and who’s dead.”

She said many of the materials were donated by Snyder Roofing of Snohomish, which has a similar experimental green roof going over one its materials sheds and is studying different technologies and how they interact with stormwater runoff and water quality.

Pierce said the roof should be completely planted by about this time next week.

Ewing said, “Right now there’s just a tremendous amount of interest in this whole idea of green roofs and green walls.” He’s particularly interested in the education element of the green roof, and the notion that school children here on campus tours will see it as an example of what can be done.

“What motivates me is getting people interested in plants — growing plants and noticing plants and sort of recognizing that plants are important,” he said. “It’s all been kind of like what we’ve been doing here with this botany greenhouse for decades. And having the chance to put a little display green roof up is just another little component of all this.”