Mould Removal & Remediation in Ontario

Surface mould on a hard, non-porous wall can be a clean-and-treat job. Once it is into plaster, drywall, insulation or timber, proper remediation means removal, containment to stop spores spreading, and drying — cleaning alone lets it return.

A patch smaller than about a square metre on a hard surface is a reasonable DIY job with protection and ventilation. Larger areas, porous materials, or anyone with respiratory sensitivity should bring in a professional with containment.

Some moulds produce irritants and allergens that affect breathing, and vulnerable people react worse. Colour alone does not determine toxicity, but extensive growth is a reason to use containment and proper protection rather than scrubbing it yourself.

For a small visible patch, no — you can see it. Testing matters when mould is hidden, health issues are involved, or you need documentation for a dispute or insurance. Use an independent tester, not the company doing the removal, to avoid a conflict of interest.

Small surface patches are cheap to treat, but priced jobs scale with the affected area and whether the underlying cause is fixed. Most single-room remediations land in the mid three to low four figures; whole-home jobs needing containment and HVAC cleaning cost several times more. Repairing the moisture source is often a separate line.

Sometimes — if the mould resulted from a sudden covered event like a burst pipe, insurers may pay. Mould from long-term neglect or condensation is usually excluded. Document the cause and keep remediation reports if you intend to claim.

Most single-room jobs run CAD 1,800-6,000, with small treatments from a few hundred dollars and whole-home remediation reaching CAD 20,000 where containment and rebuilding are needed.