Why chimney repair works differently in Markham
Markham sits in a freeze-thaw belt, and freeze-thaw is what quietly takes apart masonry, flashing and venting.
Infill and renovation work in Markham frequently reroutes venting without re-sizing it, and undersized or over-long runs are the single most common cause of poor draft we see.
Snow load and ice damming stress the roof-to-wall junction each winter; by spring the sealant that was doing the work has usually torn.
Across Rouge Fairways, Cachet, Wismer, Cathedraltown and Buttonville, 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 Main Street Unionville, the practical takeaway is that a chimney repair 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.

