Architects and gardener check up on green roof. Courtesy of the Bill & Melinda Gates Foundation. View a green roof slideshow on Flickr.

Green Roof

Irene Noguchi
05/08/2009

If you're driving down I–5 and look toward Seattle Center, you might see a patch of green stretched atop a building. That's the roof of the Gates Foundation parking lot. It's a green roof, and an example of how Seattle developers continue to incorporate more sustainable features in the designs of their buildings.

TRANSCRIPT

I'm standing in the parking structure of the Gates Foundation. Everywhere I look, there's cement: cement floors, cement ceiling. You wouldn't guess that right above me is a grassy field large enough to play frisbee on.

I walk to the top of the parking lot. It's covered by a green roof. It's about 60,000 square feet – about the size of a football field. The turf is nice and springy – with different shades of patchwork green. I feel like I'm standing on one giant Chia pet.

Cragg: "It does kinda look exactly like the top of a broccoli."

Amy Cragg is a project designer at the landscape architecture firm, Gustafson Guthrie Nichol. The Gates Foundation hired them to figure out which plants would grow best here.

They planted a bunch of sedums, which are succulents that look like mini cacti and hold water well. They absorb storm water runoff.

Craig: "This is Sedum rupestre. This one kind of reminds me of a little monster ... blue–toned plants that also have a red tinge on its leaves. It looks like a small spruce tree but the way it kinda curves up, it's like a fox's tail."

Each plant is only one or two inches high. But altogether, they act like a giant sponge.

Jeannie Iannucci is an architect at NBBJ, one of the firms that helped design the new Gates Foundation campus. She says the plants help protect the roofing membrane.

Iannucci: "So the roofing membrane, which is the waterproof membrane that keeps water out of the building, will last a lot longer if it's protected by something like a green roof. And it retains water, so that a lot less water is discharged into the storm sewer, or the combined storm and sanitary sewer."

Less water in the storm sewer system, means less pollution draining into Puget Sound. The green roof also helps to cool down the building and filter pollutants from the air.

Mike Branvold is a project manager with Pacific Earth Works. His company helped install the tiny plants up here.

Branvold: "You can definitely walk on these. We try to keep it to a minimum, but the plants are pretty tough, and if pieces of the plants do break off, they'll just root."

Noguchi: "I feel like I'm killing something right now."

Branvold: "Well, you're kinda like pruning it."

Branvold had two big problems with keeping things green. First, weeds sprouted everywhere. They could pull out the weeds. But then there were those other troublemakers ... crows.

Branvold: "The crows the whole time through while we were planting would come up here and just grab individual plants and pluck them out of the ground and eventually turn them upside down and move on to the next one. They don't eat the plants ... they just don't have anything else to do, I guess."

Branvold tried to scare them with plastic owls and fluttering ribbons, but those didn't work.

It may be awhile before anyone can tell whether the Gates roof is a success. Anne Schopf is the president–elect of the American Institute of Architects in Seattle.

Schopf: "Any landscape doesn't mature for a few years at a minimum. So I know they're going to have to wait a full dry season on the Gates Foundation to see how the plants are going to survive during the summer. That's going to be the real big test for them."

Schopf says Europe is the leader when it comes to green roofs. They're big in Germany and Sweden. But now they've also gained popularity in places like Chicago and Portland. Schopf says little by little, they're starting to take root in Seattle.

There are other green roofs in the city, but the Gates Foundation roof is one of the largest in Seattle. And the field is pretty, but it's not open to the public. So don't expect to toss a football here anytime soon. For KUOW News, I'm Irene Noguchi.

© Copyright 2009, KUOW

Editor's Note: Transcript has been edited and differs from the broadcast version. Jeannie Ianucci is an architect at NBBJ. (5/8/2009)