Most homeowners ask two questions when evaluating a contractor: Are you insured? and Do you have references? Both matter. But a contractor can be insured with an outdated certificate, and references can be cherry-picked from their best projects. The 10-point checklist below is what a thorough vetting process looks like — not what most homeowners do, but what the ones who consistently avoid problems do.
WSIB clearance confirmed at wsib.ca — certificate dated within 90 days. This takes two minutes and confirms the contractor is registered, not in arrears, and that you are protected from WSIB liability if a worker is injured on your property.
Certificate of liability insurance received — policy active and amount confirmed. Request the certificate directly, then call the insurer listed to verify the policy number is active. Minimum $1M for residential work; $2M for projects over $25K.
Business name is registered and verifiable — HST number provided. Search the business name on the Ontario Business Registry or request their HST number and verify at canada.ca. A registered business is traceable; a cash-only sole operator with no registration is not.
Trade-specific licences confirmed for any licensed trades involved. If the project includes electrical, gas, or plumbing, confirm those sub-trades hold the relevant Ontario credential — ESA, TSSA, or Ontario College of Trades registration.
At least 2 references contacted — not just received — from similar recent projects. Ask references: Did the project come in on budget? On schedule? How did the contractor handle problems? Would you hire them again? These questions reveal more than any review platform.
Online reputation searched across Google, BBB, and HomeStars. Search the contractor name and business name separately. Check for patterns — a single bad review is noise; two or three mentioning the same issue is a signal.
Written quote or scope document received — not just a verbal estimate. The contractor should be willing to put the scope, price, and timeline in writing before you commit. Reluctance to do this is a meaningful signal about how they handle accountability.
Deposit terms are 25% or less — payment schedule tied to milestones. Confirm the full payment structure before signing. More than 25% upfront shifts financial risk significantly to you; more than 50% is a red flag for any residential project.
Permit responsibility confirmed — who is pulling the permit if one is required. For projects requiring a building permit (decks, additions, structural work), confirm in writing whether the contractor or homeowner is responsible. Unpermitted work is the homeowner liability.
Warranty terms confirmed in writing — labour and materials period stated. A contractor warranty should specify the period (typically 1 year for labour) and what it covers. Verbal warranties are not enforceable.
When you cannot complete a check: If a contractor cannot provide something on this list — insurance certificate, WSIB clearance, written quote — that inability is information. A professional contractor who regularly works with Ontario homeowners has all of these available. Excuses about needing more time to find them are not acceptable before work starts.
