Ask any technician who works Whitchurch-Stouffville routes and they will tell you the same thing: the callbacks cluster in a handful of predictable places.
Many Whitchurch-Stouffville properties were re-roofed at least once without the flashing being re-detailed, leaving a cosmetic seal doing structural work.
Air-sealing and window upgrades have made Whitchurch-Stouffville 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 Stouffville, Preston Lake, Lemonville, Ballantrae and Gormley, 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.
the practical takeaway is that a ice dam risk 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.