Markham conditions that change how roof cleaning is done
If you mapped our Markham service calls on a calendar, you would see the same shape every year: the problems are created in February and paid for in November.
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.
The swing between a January cold snap and a February thaw can move a masonry assembly enough to open joints that looked sound in the fall.
Across Berczy Village, German Mills, Raymerville, Old Markham Village and Royal Orchard, 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 cleaning 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.

