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Living roof sprouts in Clinton

Landscape architect Jason Henry walks across the “living roof” on the picnic shelter at the Clinton Beach park before it was planted last Saturday. - Jeff VanDerford
Landscape architect Jason Henry walks across the “living roof” on the picnic shelter at the Clinton Beach park before it was planted last Saturday.
— image credit: Jeff VanDerford

Matthew Swett of Langley’s Taproot Design believes a green revolution is sweeping the nation. And he wants to give it a little shove.

Case in point: On Saturday, Swett, wife Sarah Birger, landscape architect Jason Henry and a dozen friends installed a “living roof” on the recently constructed picnic shelter at Clinton Beach park.

Sometimes called “ecoroofs,” the idea is to build a roof composed of elements and organisms that move through the natural life cycle.

“Planting on roofs is one of the most innovative and quickly developing fields in the worlds of both horticulture and architecture,” Swett said.

The day before, a contractor had laid a unique substrate material — consisting of lava rock pumice, peat, minerals and organic fertilizers — four inches deep over the shelter’s 520-square-foot roof.

Then 27 varieties of hardy drought-resistent plants were carefully buried in the soil, among them donkey tail, alpine mouse-ears, cliff maids, nutmeg thyme and lots of stonecrop variations.

The vegetation will be watered for one year until the plants get established. Then they’re on their own.

“It’s pretty much survival of the fittest,” Henry noted. “Most will live, some will fail, but that’s what happens in the natural world.”

Eventually, the plants will spread out to form a colorful carpet — featuring purple, red, white, yellow and peach flowers in the spring — designed to crowd out weeds.

Swett, who designed the park for the Port of South Whidbey, got interested in the green roof concept some years ago.

Currently there are only three or four residential living roofs on Whidbey; one of them shelters Swett and Birger’s home.

“At first we were going to use local lumber and take dirt out of our garden,” Birger recalled. “The more we read, the more we realized there is a right way to do it; garden soil won’t cut it.”

Their research led them to consider the roof slope factor, design loads, drainage, irrigation, accessibility for homeowners and cost.

One thing they learned was the need to utilize three “geotextile” membranes below the soil:

• The first is a waterproof membrane protecting the actual roof, be it wood, metal, shingle or tile. It also keeps roots from penetrating the roof.

• Next is a special filtering fabric that keeps the soil from washing away.

• The third membrane provides erosion control and prevents the soil from sliding off a pitched roof.

“We’re doing one project at a time, learning more as we go along,” Birger said.

Costing roughly $10 per square foot, Swett estimates a living roof will last twice as long as a normal wood or metal roof.

But why do it in the first place?

Benefits include heat insulation, noise reduction, absorption of storm water, reduction of urban heat, increased longevity of roofing materials and, of course, a greener environment.

“The roof acts as a thermal buffer, preventing temperature extremes,” Swett said. “It absorbs heat and cold very well and that could lead to energy savings over what we expect to be the very long life of the roof.”

Swett added that a green roof can help reverse the ubiquitous paving of the landscape ever more prevalent in the modern world.

He’s not alone.

Though the basic concept originated in Europe, it has spread rapidly across the Atlantic. When the Ford Motor Company revitalized its Dearborn, Mich. truck final assembly building, it planted the largest green roof in the world. It covers 454,000 square feet and created a 10.4-acre garden in the process.

There are no commercial applications on Whidbey yet, though the idea may be catching on among locals.

Langley librarian Robin Obata is thinking seriously about installing a green roof for her own home.

“We have a metal roof growing plants and moss already,” she joked. “We don’t want to have to pressure wash every year and this would be a solution.”

“And I’ve discovered today it’s easier than I thought it would be,” she said while tucking a Cape Blanco stonecrop into the soil.

As the roof was taking shape, Swett was busy applying decorative glass tiles made from re-cycled pop bottles to the shelter’s columns.

Port commissioner Lynae Slinden considers the project a good example of innovation by local designers, artists and craftsmen.

“We wanted to do something that gives visitors a marvelous first impression of what our island is all about,” she said.

At 10 a.m. Saturday, the port will host a park dedication to coincide with Clinton Days; visitors can take an up-close look at the living roof for themselves.

For more information on ecoroofs, call Taproot Design at 360-321-4447 or e-mail mjswett@whidbey.com.

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