15 questions to ask a deck contractor

What’s inside the PDF

• WSIB clearance + general-liability certificate confirmations
• Footing depth and post-base detail (the framing question 80% of homeowners forget)
• Joist spacing and ledger-flashing approach
• Decking fastener system (face-screw vs hidden clip — affects warranty)
• Railing engineering for decks above 5 ft 11 in (OBC trigger)
• Payment schedule + Construction Act lien-holdback discussion
• Warranty terms: what's covered, what voids, who pays for return visits
• Three reference projects you can drive past

How to use it

• Print one copy per contractor you're interviewing — keep them as the record
• Note their answers in the margin during the meeting, not after
• If a contractor refuses to answer any of these, that itself is a data point
• Use the comparison worksheet to lay the answers side by side later

Why this template exists

Most contractor interviews go badly the same way — the homeowner asks general questions about timeline and price, and the conversation never gets to the questions that actually predict project quality. The fifteen items in this checklist are the ones I'd ask in your position. They split roughly into three groups: credentials (WSIB, insurance, references — table stakes, but check them), technical detail (footing depth, joist spacing, ledger flashing, fastener system — these are the choices that determine whether the deck lasts 12 or 25 years), and payment and warranty (the Construction Act lien holdback in Ontario, what the warranty actually covers, who pays return visits). A contractor who can answer all fifteen in plain language is a contractor worth interviewing further. One who can't, isn't.