IT”S ONE OF THOSE APOCRYPHAL stories that has become part of the folklore of Toronto. The architect Frank Lloyd Wright – the genius behind Fallingwater and the Prairie School movement – hated Toronto City Hall when he saw the blueprints a few months before his death in 1959. Most Torontonians loved it. With two office towers twisted whimsically around a council chamber shaped like a flying saucer, the building became a logo for the city of Toronto more than a decade before the CN Tower took over that role. Forty years after it opened, the futuristic building is still like no other structure on Earth.

Canadians have long since gotten used to the radical design, but the structure is still on the cutting edge of building technology. Chock it up to something called a “green roof.” It’s not a new colour scheme – the green roof that officially opened on top of the 3,200 sq. ft. podium area of the building complex in 2002 is an environmental innovation that may someday change the way all cities are designed.

Toronto City Hall’s green roof is an exquisitely simple idea; a series of low-maintenance gardens that collect rainwater, filter out damaging UV sunlight and keep the tenants below them cool in the heat of summer. The black oak savannah prairie that grows in one corner recreates one of North America’s most endangered ecosystems. The bird and butterfly garden gives harried office workers an esthetically pleasing park, while the kitchen garden, with its tomatoes, peppers and herbs demonstrates just how functional a green roof can be. Funded through a public private partnership that includes the City of Toronto, the Toronto Atmospheric Fund, The National Research Council and an organization called Green Roofs for Healthy Cities, the $1 million demonstration project shows the public one way in which cities in the future will combat pollution and cut down on greenhouse gases. It is part of the growing trend toward green buildings.

Green buildings may be the biggest architectural development of the new century. More philosophy than design, the green building concept affects everything from the type of materials that go into the walls to the place where the building is sited in relation to sunlight, public transportation and urban density. At their most sophisticated, green buildings resemble Biosphere 2: self-contained units that collect most of their own water and energy, filter the interior atmosphere and grow the salad greens served up in the company cafeteria. But even an unassuming brownstone can adhere to many of the green building principles.

“There are a lot of different ideas about what makes buildings green,” says Halifax-based architect Keith Robertson. “For some people it means energy efficiency or a healthy working environment. Some people use green to refer to the way the building is built using sustainable building practices. The marketplace has its own definition.”

As principal with the architectural firm Solterre Designs, Robertson has pioneered environmentally-friendly building practices like passive solar design, energy efficient systems and healthy building materials systems in Atlantic Canada. He says that green buildings are already becoming a major marketing tool for building owners and managers looking for ways to increase the competitive advantages of their buildings. “There is a distinct marketing advantage to having a building that has a green rating. In a number of North American cities it’s already been shown that these buildings rent faster, at a higher rate and with lower vacancy rates.” But the real cost effectiveness of green buildings comes in the debit column of the ledger. Operating, maintenance and future renovation costs are often significantly lower in a green building.

The results can be dramatic, especially when a green building policy is implemented as part of an overall green strategy. The new corporate headquarters at NMB Bank in the Netherlands reduced energy consumption to levels that were a tenth of what they had been in their old building. The money saved was small compared with the PR value that came with the move: NMB’s improved corporate image is being touted as the main reason for that institution’s rapid rise to become the second largest bank in the country.

With cost savings and improved marketability, why isn’t every building owner jumping on the green bandwagon? Lack of education, promotion and government incentives all play a role, but a big part of the reason, says Robertson, is the lack of a green building rating system in Canada. The industry is working to change that.

Some building owners are looking to the United States for guidance. The LEED Green Building System is the first serious attempt in that country to create a ratings system. An acronym that stands for Leadership in Energy and Environmental Design, LEED is a volunteer rating code created by U.S. Green Building Council. Under the LEED system, green buildings are rated under five categories: sustainable sites (the capability of a building to collect things like rainwater and solar energy), water efficiency, energy and atmosphere, use of materials and resources and indoor environmental quality. The LEED system also has a “bonus category” that recognizes innovation in green design when it exists.

For building owners and managers who might be intimidated by the expense and complexity of going green, the best thing to do is start small. Jumping into the green building trend could be as simple as installing computerized thermostats or low-flow water fixtures throughout a building, or as complex as designing a LEED-quality building from scratch.

“The development of green buildings is a constantly moving target,” says Robertson. “The general trend right now is to keep raising the bar, to keep finding new ways to design and promote green building practices. The idea has definitely arrived.”