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Dagmar Hungerford's new green roofs were inspired by goats. "My husband and I were on our honeymoon in 1971, driving our Volkswagen beetle from Nanaimo to Long Beach," she recalls. "In Coombs we stopped beside this general store with a pitched roof. It had green grass and wildflowers growing all over it, and standing right on the roof were two goats. The whole image just struck me -- it was a magical moment, a bit of mystery and surprise."

The general store was The Old Country Market, which thirty years later still sports both green roof and goats. Along with early Hornby Island experiments by Arthur Erickson and Blue Sky Architecture, it is, by sheer exposure, probably one of the most influential green roofs in B.C.

Time flies, and the rustic origins of green roofs in B.C. have since mingled with Japanese and European design innovations. Ms. Hungerford and her husband now own two houses with green roofs -- quite a bit more sophisticated than their early-seventies ancestors -- in West Point Grey.

Ms. Hungerford appeared as the Saturday Morning Gardener on Paul Grant's CBC morning show for five years, and has also written essays for several gardening publications, including the book The Twelve Month Gardener. Over the years she sustained her interest in green roofs by clipping magazine pictures of sod-roof Scandinavian cottages and watching for more modern versions on trips to Europe. "Germany was the forerunner in creating large commercial green roofs, and when I was in Berlin I saw a lot of them on institutional buildings."

Two years ago, she and her husband began drawing plans with local architect Werner Forster for their home and adjacent rental property on a sloping neighbourhood site near Spanish Banks. Mr. Forster, who passed away in the fall of 2005, was the architect behind many of Vancouver's top restaurants, including Il Giardino, le Crocodile, and West.

To build to the height they wanted and minimize the impact on their neighbours' views, the plans called for flat rooftops. "When we were told that to get the elevation we wanted, we needed to have a flat roof, it was an opportunity where I thought, 'Oh my god, I can have my own green roof' We explained to Werner the houses needed to be engineered for that, and he thought it was very funny that we wanted to put a green roof on a house in West Point Grey. But he was open-minded and very innovative."

Many Vancouver developers and contractors are wary of installing green roofs because of leaky-condo syndrome. For assistance Ms. Hungerford enlisted Angel Ridge Landscape, who installed the garden courtyard of the Opus Hotel in Yaletown.

She also credits Randall Sharp of Sharp and Diamond Landscape Architecture, whom she met at the 2005 Vancouver Garden Show, with giving her the confidence to do some of the work herself.

Leakiness is not an issue, says Mr. Sharp, as a professionally installed green roof system will last 50 to 70 years. "They can cost $8 to $20 more per square foot than conventional roofs, but that includes a year of what we call establishment maintenance. Plus they reduce HVAC costs, and through energy savings, can pay for themselves within 10 years."

Green roofs come in two varieties, intensive and extensive. Intensives are like patio gardens, meant to be watered, fertilized and maintained. The Hungerfords' roofs are a certain type of extensive roof, which Mr. Sharp calls an eco-roof. Meant to be low-maintenance and generally inaccessible like other extensives, these are self-sustaining ecosystems planted with hardy perennials. In the Hungerfords' case, their roof mimics local coastal bluffs, using native species like nodding onion, coastal strawberry, alumroot, stonecrops and sea pinks.

"We also chose some non-native grasses like blue Rocky Mountain fescue," Ms. Hungerford says. "They're very hardy and give a change in texture, as they have a nice clumping look."

"We call them coastal meadows in the sky, " says Mr. Sharp, who helped install a 1500-square-foot extensive green roof on the Sechelt Justice Building. "A roof is like an escarpment or bluff, that experiences wind shear and extremes of moisture and dryness. For low-maintenance extensive roofs you need grasses, succulents and wildflowers that are able to handle those conditions."

Several years ago, Mr. Sharp started taking trips to Saturna Island and Whytecliff Park, cataloging the plants that thrive there, and bringing seeds to local nurseries to have them grown in large quantities. Using the roof of his garage as a test lab, he experimented with different plant and soil combinations. Judging by the carpet of sedums and grasses clinging to it, the experiments were a success. The lightweight soil Mr. Sharp uses also has an esoteric B.C. origin. He makes it sound good enough to eat. "Mostly we use a lightweight soil mixture made of black pumice from the Nazko volcano near Quesnel, mixed with local worm castings and fresh compost."

Besides the eclectic pleasure of having a coastal meadow or English garden over your head, according to Mr. Sharp and Ms. Hungerford there are several practical advantages. One is thermal insulation. Green roofs keep houses cool in summer, absorbing heat and releasing moisture gradually through a process called evapotranspiration. In cold months the soil and biomass holds in heat.

Sound insulation is another bonus. The City of Richmond is installing three green roofs on its new Sea Island Firehall. One of the major benefits, says Mr. Sharp, will be dampening the constant roar of jet engines. "It's right under the flight path, and planes are taking off every few minutes. The green roofs will cut the noise down and give the guys in the hall a chance to sleep."

The "heat-island effect" is the ecological term for the temperature spike city-dwellers cope with during the dog days of summer. It's like the old Drifters song, Under the Boardwalk: "When the sun beats down and burns the tar up on the roof/ And your shoes get so hot you wish your tired feet were fireproof." On a hot day, ambient temperatures downtown can be 4 C higher than in rural areas. This is due to solar absorption by concrete and asphalt, which can reach painful surface temperatures of over 65 C. Like summer lawns and meadows, evapotranspiration by green roofs helps lower temperatures -- and reduce smog in the process, though that's another story.

Storm water retention is a little-known subject, and Mr. Sharp is passionate about it. When discussing it he often apologizes for ranting. "Most people don't know it, but here in Vancouver our storm water goes into the combined sewer system. In heavy rains the system goes over capacity and floods raw sewage into English Bay, Burrard Inlet and the Fraser River." A green roof, he says, can absorb up to 75 per cent of annual rainwater, taking some of the pressure off the sewer system.

These were all important considerations for Ms. Hungerford, but the appeal of integrating architecture with a wild ecosystem brings her right back to her honeymoon. "Point Grey is so beautiful, with the sea, the beach, and the mountains; we felt it was really important to fade into the landscape. Though you can't do that with only a green roof, you can provide some habitat for local creatures, and soften things a little bit."