The local factors behind shingle replacement & roof replacement in Cambridge
Ask any technician who works Cambridge routes and they will tell you the same thing: the callbacks cluster in a handful of predictable places.
Post-war subdivisions across Halton share the same construction generation, so when one street starts showing the same defect, the neighbours usually follow within a couple of seasons.
Range hoods and basement bathroom fans routinely out-pull an older flue, so the house depressurises and the flue reverses — a Cambridge problem that looks like a chimney fault but starts elsewhere in the building.
Across Doon, Alison, Preston Heights, Elgin Park and Blair Road, 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 the Grand River, the practical takeaway is that a shingle replacement & roof 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.