Why ice dam prevention works differently in Toronto
What makes ice dam prevention in Toronto unusual is not the technique, it is the age spread of the housing: a single route can cover 1910 brick and 2019 factory-built venting.
Salt spray and road grit carried by winter wind accelerate corrosion on exterior metal components far faster in Toronto than the manufacturer's rating assumes.
Air-sealing and window upgrades have made Toronto homes far tighter than they were designed to be, and a tight house starves a natural-draft appliance of the make-up air it needs.
Across Leaside, Hoggs Hollow, East York, Thorncliffe Park and Greektown, the housing stock changes street by street, and the correct method changes with it. A century home with a soft-brick stack does not get the same treatment as a 2010 build with a factory-built vent — using one method on both is how systems get damaged.
If you live anywhere near the CN Tower, the practical takeaway is that a ice dam prevention visit should start with an assessment, not a tool. Any crew that begins work before telling you what they found is guessing on your behalf.