The local factors behind gas line & b-vent conversion in Caledon
The difference between a $200 service call and a $6,000 rebuild in Caledon is usually about eighteen months of ignoring a small symptom.
Wind loading off Lake Ontario pushes driving rain against the south and west faces of a house, which is why water entry so often shows up on one side of a Caledon home and nowhere else.
Salt spray and road grit carried by winter wind accelerate corrosion on exterior metal components far faster in Peel than the manufacturer's rating assumes.
Across Southfields Village, Alton, Mayfield West, Cheltenham and Palgrave, 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 gas line & b-vent conversion 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.

