Don't bank on a warranty visit buying you more time to lien. In Ontario, even the lawyers who write about this won't commit to an answer.
Short answer
Not reliably, and in Ontario the honest answer is that it's genuinely unclear. Protect yourself by treating your original last day of supply as the deadline, not a later warranty or deficiency visit — and don't wait to find out which way a court would call it.
Ontario's preservation deadline runs from several possible trigger events, and one of them is your own last supply. As Treadstone Law's overview puts it, the 60-day clock starts from whichever comes first of “publication of a certificate of substantial performance, completion, abandonment or termination of the contract, or your own last supply of services or materials.” A later warranty call could, on its face, look like a further supply “under the contract” — but Treadstone Law's deadlines guide won't say that a warranty visit resets anything. It states only that the Act “ties the trigger to the last day on which you supplied services or materials under the contract,” and then adds: “If there is any question about when you last supplied work or materials, you need a lawyer to analyze the specific facts immediately.” That's a direct admission that the question is fact-specific, not a settled rule you can rely on generically.
And there's no relief for lateness if you guess wrong: “Missing the lien deadlines does not end your right to sue for the money owed… but you lose the security.” Guessing that a warranty visit extended your window, and being wrong, costs you the lien — not just the argument.
British Columbia's Builders Lien Act reads differently on this point. The filing window opens from a discrete, dated event: s.20(1)–(2) of the Builders Lien Act runs the 45-day filing period from the certificate of completion, or from the completion, abandonment or termination of the head contract or improvement — not from an open-ended “last supply” test the way Ontario's does. Textually, once that certificate date or completion date has passed and the clock is running, a warranty call afterward doesn't reopen a window the Act already fixed to a specific date.
Worked example: a certificate of substantial performance publishes on March 1. In Ontario, the 60-day preserve deadline runs to roughly April 30 for anyone whose last supply predates the certificate — but a sub who returns on May 20 for a warranty callback on a leaking window faces a genuinely open question about whether that visit is itself a “last supply” resetting their own clock. The safer, and only reliable, move is to preserve by April 30 regardless and treat any later argument as a bonus, not a plan.
Crews sometimes delay filing because “we're still doing warranty work, so the clock hasn't started.” That's exactly the assumption the sources above refuse to confirm. File against your original last substantive supply date, and see preserving versus perfecting a lien for the two-step deadline itself.
Related: lien deadlines across Canada, warranty period vs. maintenance period, a drywall firm that missed its lien window.
A 30-minute call is enough to see where your contracts, quotes and lien deadlines are leaking money.
