By Jim Adair
The Toronto-Dominion Centre now includes six office towers with four million square feet of space and more than 20,000 tenants.
Then renowned architect Ludwig Mies van der Rohe designed Toronto’s Toronto-Dominion Centre in the mid-1960s, he probably didn’t think of putting grass on the roof of the Banking Pavilion, the anchor at the bottom of the centre’s original two towers. But Roger Johnson, TD’s senior vice-president of Enterprise Real Estate, thinks the new “green roof” would have met with the architect’s approval.
“The details that he designed into this structure still exist today – simple details like the yellow flowers in the branch in the fishbowl, and the Barcelona chairs in the lobby and the branch are his design,” says Johnson. When working on the plans for the green roof, after looking at “many design iterations,” the final result “mirrors the lighting structure in the branch…obviously the design intent is clean lines and the simplicity that he strove to design into these structures had to be maintained.”
Completed in 1967, the Toronto-Dominion Centre was the tallest building in the Commonwealth and the first of the modern era of skyscrapers in Canada. B+H was architect of record in a joint venture with John B. Parkin and Associates. Fairview Corporation (now Cadillac Fairview) was the developer, and Allen Lambert, chairman of TD Bank, was credited as the driving force behind the project.
When it came time to replace the old roof on the pavilion, as part of TD’s commitment to be environmentally responsible, it was decided a green roof would be installed. It cost about 25 per cent more than a traditional roof, says Johnson.
Among the designs considered were those that included a TD logo and some plans that supported several types of plant life. The roof can’t be seen from the street and is not accessible without special equipment, but it can be viewed from thousands of windows in the skyscrapers surrounding the pavilion.
The grass is planted in rows of bottomless planter boxes that form part of the roof’s structure.
The roof is on the north side of the complex and receives sunlight only about 15 per cent of the time, so it was determined that only a hardy evergreen native plant – Creek Sedge Grass – would be used. It will grow to about 18 inches.
The grass is planted in rows of bottomless planter boxes that form part of the roof’s structure and recreate the grid pattern of the Mies van der Rohe design. An irrigation system is also included, along with a leak detection system.
Johnson says the green roof layers and additional insulation brought an unexpected benefit – the R-value of the roof was doubled to R-20.
Among the other benefits, says TD, is that the green roof helps cool the building and prevents the urban heat island effect in summer, while helping reduce heat loss and energy consumption in winter. It helps with sound insulation and absorbs rainwater, helping to reduce the need for treatment of run-off. It creates a habitat for birds and other small animals and should increase the lifespan of the roof and increase its real estate value, says TD.
“As we did this project, 75 per cent of the waste created was diverted from landfills” though recycling and reuse, says Johnson.
