Markham conditions that change how roof flashing repair is done
Most Markham homeowners book roof flashing repair for one reason and discover a second problem on the same visit.
Many Markham properties were re-roofed at least once without the flashing being re-detailed, leaving a cosmetic seal doing structural work.
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.
Across Commerce Valley, Angus Glen, Devil's Elbow, Milliken 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 roof flashing 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.

