Construction Liens in Ontario: How They Work and Filing Deadlines

A construction lien is one of the defining features of Ontario’s Construction Act, 2019 (which replaced the former Construction Lien Act). It gives anyone who supplies services or materials to an improvement on real property a way to secure payment by registering a claim directly against the property’s title, rather than relying solely on a lawsuit against whoever owes them money.

The idea behind the lien is fairly simple: construction work increases the value of a property, and the people who contributed labour or materials to that increase in value should have a way to reach that value if they aren’t paid. A lien doesn’t create new money out of nowhere — it secures a claim against funds the owner is generally required to hold back during the project, and against the property itself, up to the value of the unpaid work or materials supplied.

It’s worth being clear about what a lien is not. It isn’t a judgment, and it doesn’t by itself determine that money is actually owed — it’s a notice and a security mechanism that preserves a claim while the underlying dispute about who owes what to whom still needs to be resolved, whether through settlement, court, or another process. A property owner who disputes a lien claim is generally entitled to defend it on the merits, the same as any other claim.

Lien rights under the Construction Act extend to every level of the typical construction contract chain. General contractors who contracted directly with the owner can claim a lien for unpaid amounts owing to them. Subcontractors and sub-subcontractors, who may never have dealt with the owner directly, can also claim liens for the value of services or materials they supplied. Material suppliers who delivered goods to the project site can claim a lien, as can individual workers owed wages for labour performed on the improvement.

This layered structure is deliberate. Because an owner’s payment to a general contractor doesn’t guarantee that money flows down to the subcontractors and suppliers who actually did the work, the lien right gives everyone in the chain independent leverage to secure payment directly against the property, rather than depending entirely on the party above them passing payment along. Our article on subcontractor agreements in Ontario looks at how this plays out in the contract terms themselves.

A lien claim is generally limited to the actual value of what the claimant supplied and wasn’t paid for — it doesn’t allow a claimant to recover damages for other kinds of losses, such as lost profit on other jobs, through the lien process itself. Those kinds of claims, if they exist at all, are typically pursued separately as an ordinary breach of contract claim rather than through a registered lien.

The first and most important deadline is preservation. A lien claimant generally must register a claim for lien against the property’s title within 60 days of the relevant triggering event. What counts as the triggering event depends on the circumstances — commonly, it’s the last day on which the claimant supplied services or materials to the improvement, or the date a certificate of substantial performance for the relevant contract is published, whichever applies to the claimant’s situation.

Sixty days is not a long window in the context of a construction project, and it runs regardless of whether the parties are still negotiating, still exchanging invoices, or still hoping the payment dispute resolves informally. Missing this deadline generally extinguishes the lien right permanently — there’s typically no way to revive a lien once the preservation period has passed.

It’s also worth noting that the Construction Act sets an overall maximum period after which lien rights generally expire even if an earlier triggering event hasn’t yet been pinned down, so claimants shouldn’t assume they can wait indefinitely for a clearer triggering date to emerge before acting. When in doubt about which date applies, treating the earliest plausible date as the deadline is the more cautious approach.

Preserving a lien is only the first step. To keep the lien alive, the claimant generally must then perfect it within a further 90 days after the lien was preserved. Perfection involves issuing a statement of claim in court setting out the basis for the lien claim, and registering a certificate of action against the property’s title referencing that court proceeding.

Perfection effectively converts the registered notice into an active court claim. Without it, a preserved lien generally expires at the end of the 90-day period, even if it was properly preserved in the first place. This two-step structure — preserve, then perfect — is one of the most unforgiving aspects of lien law, since each deadline runs independently and missing either one typically has the same result: the lien right is lost.

Because perfection requires formally starting a court proceeding, it’s a more involved and more costly step than preservation, and it generally brings the dispute into the ordinary litigation process from that point on. Some claimants preserve a lien promptly to protect their position, then use the 90-day window to try to negotiate a resolution before committing to the cost of actually perfecting it.

Registering a claim for lien places a notice directly on the property’s title at the relevant land registry office. This doesn’t transfer ownership or give the lien claimant any right to occupy or use the property — what it does is encumber the title, meaning the lien shows up in a title search and generally has to be dealt with before the property can be sold or refinanced cleanly.

In practice, this gives lien claimants real leverage even before a court proceeding is resolved, because most owners and lenders want a clear title and will move to resolve a registered lien — through payment, negotiation, or a formal discharge process — rather than leave it outstanding indefinitely. Our article on discharging a construction lien covers how an owner can remove a lien from title, including by posting security in its place.

Once a lien is preserved and perfected, it generally proceeds like other court litigation, moving through pleadings, evidence, and potentially a trial if it isn’t resolved earlier. In practice, many lien claims settle well before trial, since the pressure a registered lien places on a property’s title often brings the parties to the table faster than an ordinary breach of contract claim would.

Liens also interact closely with other parts of the Construction Act — the holdback an owner is required to retain is generally the fund a lien claim is intended to reach, and a construction bond may sometimes stand in as alternative security. For disputes that don’t fit neatly into a lien claim, Ontario’s interim adjudication process offers another, faster route to a binding (if interim) resolution. This article explains generally how liens work in Ontario; it isn’t a substitute for confirming the specific deadlines that apply to a particular project, which can turn on facts a general summary can’t capture. See the construction insights hub for more, or our contact page if you have a general question about this site.