Homes in Ajax rarely fail all at once — they fail slowly, through one heating season at a time.
Infill and renovation work in Ajax frequently reroutes venting without re-sizing it, and undersized or over-long runs are the single most common cause of poor draft we see.
Older Ajax stock was built when soft lime mortar and clay liners were the standard; modern high-efficiency appliances vent very differently, and the mismatch causes condensation the original builder never planned for.
Across South Ajax, Ajax Waterfront, Riverside Ajax, Central Ajax and West Ajax, 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 winter roof prep 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.