Why chase cover replacement works differently in Markham
Markham sits in a freeze-thaw belt, and freeze-thaw is what quietly takes apart masonry, flashing and venting.
Salt spray and road grit carried by winter wind accelerate corrosion on exterior metal components far faster in York than the manufacturer's rating assumes.
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.
Across Royal Orchard, Wismer, Milliken, Cornell and Old Markham Village, 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 chase cover replacement 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.

