Every once in a while Reading Toronto reposts a previous entry because the media catches up with some of the ideas it contained. This morning on CBC radio Graeme Stewart talked about ERA Architect's plan to "green" a thousand or so Toronto high rise towers. Here is the original:



By Graeme Stewart

There has been much talk in recent months of Toronto’s strategies for a significant reduction in greenhouse gas emission. Incredibly welcome news, there seems to be a flood gate of creative strategies for seriously combating climate change. Not yet part of the discussion however is the opportunity inherent within Toronto’s extensive stock of hundreds of bulky concrete residential slabs. Typically viewed with scepticism as ‘mistakes’ from the 60’s and 70’s, they may in fact be one of our greatest opportunities for creating a sustainable region.

These buildings are energy pigs. Counterintuitive to the accepted theory that density aids sustainability, our stock of again modern slab apartments demands more energy per square meter than any other housing type; a full thirty percent more than a contemporary single detached house. Though certain efficiencies are gained from reduced land coverage, transit use and the like, exposed slab edges, minimal insulation, single glazing and aging mechanical systems give these buildings a huge environmental impact.

As a result, a typical twenty five-storey slab building contributes more than one thousand tonnes of carbon dioxide alone. These buildings demand environmental consideration, and due to their relatively straight forward structure and boxy facades, environmental upgrade can be achieved with relative ease. This has not been lost of two members of U of T’s Faculty of Architecture, Dr. Ted Kesik and Ivan Saleff. After running numerous simulations, they have concluded that this building type may be the most cost effective candidate for retrofit in the City.

While glass window walls are the cladding fad of the day, the bulky masonry walls of these older slabs offer an ideal surface to support over-cladding systems. This approach extensively insulates the exterior of the buildings, encloses balconies and covers slab edges, which is predicted to halve energy requirements. Additionally, these buildings provide an economy of scale that makes geothermal heating, solar electric/water heating (locating panels on generous blank end walls), and green roof technology highly effective investments. These strategies would give the opportunity for carbon reductions of over two thirds the current output. In other words, a hundred and eighty unit apartment building would require less green house gas production than fifty traditional bungalows. Suddenly density begins to make sense.

These aging buildings offer endless opportunities for green modification. Containing the structural capacity to handle the addition of new floors, the buildings themselves could be the launching pad for (appropriate) intensification. By design, the concrete walls create the necessary fire separations to allow for mixed use, anything from at-grade retail, office conversion, to light industry.

And opportunities abound beyond the building walls. Sited on hectares of underutilized land, largely relegated to surface parking, this adjacent open space offers the potential for (...read more...)