Insulation work in Toronto usually falls into a few buckets: attic top-up or full re-insulation with blown-in cellulose or fiberglass, spray foam at roof decks and rim joists, and vapour barrier or air sealing work that goes alongside a roof replacement or renovation. A lot of it overlaps with roofing, since a leaky or poorly ventilated attic wrecks insulation fast, and a re-roof is often the easiest time to fix R-value and ventilation problems at once. We list 147 insulation contractors serving the city, ranging from small crews that specialize in attic top-ups to larger firms that handle spray foam, basement insulation, and full building envelope retrofits.
Before hiring, ask for the R-value they're installing (Ontario building code minimums matter here), whether they're addressing existing bathroom fan and pot light penetrations, and how they handle attic ventilation (baffles, soffit clearance) so the new insulation doesn't get compressed or damp. Get a written scope, not just a square footage price, since material type and depth change the number a lot.
Our scoring weighs verified licensing and insurance, years in business, review consistency across platforms, and responsiveness to complaints. Full detail is on the methodology page. If you're also planning roof work, the ranked roofing contractors guide is a good place to cross-check the same companies.