Canadian Consulting Engineer
Plan to jacket 1970s apartment towers has multiple benefitsEngineering
Ageing highrise apartment buildings dot the skyline in most large Canadian cities. Most of these concrete sla...
Ageing highrise apartment buildings dot the skyline in most large Canadian cities. Most of these concrete slab buildings date from the 1950s to 1970s and are not only huge energy guzzlers but present the people who live in them with a stark and isolated environment.
During the era when the towers were built, energy was cheap, so they were not usually insulated. Their windows are single pane, and their balconies are crumbling.
As well, they sit in huge open expanses as was required by planners. The result is that the people who live in these towers — many of them immigrants and people with low incomes — live far away from shops and other amenities, with long walks along the proverbial windswept landscape to take public transit.
All this might change in Toronto, thanks to the Mayor’s Tower Renewal project, which was officially launched this fall.
The Tower Renewal project builds on work at the University of Toronto School of Architecture by professor Ted Kesik (also a civil engineer), as well as E.R.A. Architects. Halsall Associates (Kevin Day) among others have also been involved.
The proposal is to retrofit the towers in radically new ways to make them more energy efficient (50% by one estimate) and to make them much more user friendly at ground level, by filling in the open land with community gardens, stores, markets and other amenities.
One of the most intriguing proposals involves wrapping the existing building envelopes in new cladding. This new cladding would be a kind of “armature” behind which new services such as communications cable or even geothermal piping could be installed. The new outer facade could be added without too much disturbing the apartment dwellers. It would add insulation to the building and in some cases could provide a double facade for natural ventilation. Individual panels of the cladding could be removed for maintenance and replaced as necessary.
Stewart says that the most desirable kind of new cladding would be metal, and he hopes that new products will be developed in Canada that would offer the kind of aesthetic choices that are available in Europe now. He says that such technological developments could be a great new manufacturing opportunity in Ontario.
Another proposal is that the towers could be fitted on the exterior with waste management shutes for collecting recyclable materials, etc. Currently few apartment buildings have the necessary interior infrastructure for waste recycling, adding to the city’s waste handling headaches.
Instead of trying to rebuild crumbling balconies, which is very expensive, the balconies would be enclosed. They would also be fitted with local alternative energy systems. Graeme Stewart of E.R.A. Architects explains that presently most of the buildings have large gas boilers, while about 20% (the real energy guzzlers) use electricity for heating. Their large south facing walls would be perfect for solar systems, Stewart explains. In some cases geothermal systems and also district heating systems would be added.
According to the Mayor David Miller’s office, Toronto has 1,000 concrete frame high-rise apartment buildings, so the scope of improvement is vast. Not least, the mayor sees the renewal project as a way of improving the living conditions in the city’s affordable housing stock. Many of the highrise apartments are large and spacious compared to new units.
To begin with, four pilot projects are being studied in different areas of the city. The pilot projects are in Etobicoke, Scarborough, North York, and downtown at 200 Wellesley Street, with three being owned by private developers, and a fourth owned by the Canada Mortgage and Housing Corporation.
The city has established a special Tower Renewal Project Office, and best practice guidelines for the project should be finalized by early 2009.
It is acknowledged, however, that one of the biggest challenges will be steering the retrofit projects through the approvals process. As the mayor’s report summary puts it, the “Mayor’s Tower Renewal is an ambitious but important plan that will require unprecedented levels of cooperation and coordination across all city divisions and agencies, combined with a wide array of external partners.”