For contractors, subcontractors, and suppliers who haven't been paid — the path from unpaid invoice to enforceable claim, in order.
Who this is for: Anyone who supplied work, services, or materials to an Ontario construction or improvement project and hasn't been paid — general contractors, subcontractors, trades, and material suppliers. What you'll get: the Construction Act framework in plain language, the ordered steps to protect and enforce a lien, a timeline table, and the mistakes that quietly destroy lien rights.
⚖️ This is a general guide, not legal advice. It can't account for your specific situation. Use it to get oriented, then confirm the details with a licensed Ontario lawyer.
Why this guide is unusually deadline-driven
A construction lien is a powerful right under Ontario's Construction Act: if you improve someone's land and aren't paid, you can register a claim against that land as security. But this power comes with a catch — the deadlines are short and strict, and missing one usually ends your lien rights permanently.
⚠️ READ THIS TWICE: Construction lien deadlines are among the most unforgiving in Ontario law. There are two key clocks — one to preserve the lien, and a second to perfect it by starting a court action. Under the Construction Act, as of 2026, the counts are 60 days to preserve and a further 90 days to perfect (the older 45-and-45 counts still apply to contracts or procurement processes started before 1 July 2018). The timeline below shows the sequence; the day the clock starts is the hard part. You must confirm your own dates — ideally with a lawyer — the moment you suspect you won't be paid. A lien is one of the few legal rights you can lose simply by waiting.
A second wrinkle: Ontario moved from the older Construction Lien Act to the modernized Construction Act, and which set of rules and timelines applies can depend on when the project's contract was entered into or the project began. That's another reason to confirm the rules that apply to your specific project rather than assuming.
The roadmap at a glance
| Phase | What happens | Deadline sensitivity |
|---|---|---|
| 1. Confirm you have lien rights | Establish you supplied to an "improvement" and are owed money. | Foundational |
| 2. Preserve the lien | Register a claim for lien against title (or give it, for some projects). | 🔴 Hard deadline — 60 days |
| 3. Perfect the lien | Start a court action and register a certificate of action. | 🔴 Hard deadline — a further 90 days |
| 4. Holdback & trust | Understand the statutory holdback and trust claims that back you up. | Ongoing |
| 5. Prompt payment & adjudication | Use the prompt-payment/adjudication regime to get paid faster. | Time-limited steps |
| 6. Resolve | Settle, or proceed to the lien action / trial. | Varies — confirm |
Reminder: Treat every "deadline" cell as "verify the current number now." This roadmap teaches the order and logic, not the day counts.
Phase 1 — Confirm you actually have a lien right
What happens: You establish the basics that give rise to a lien.
- You supplied services or materials to an improvement to land (construction, alteration, repair).
- You are owed money for that work.
- You're claiming against the right property and the right parties (owner, contractor above you in the chain).
Who does it: You, with help from your records and (ideally) a lawyer.
What you need: Your contract or purchase order, invoices, delivery records, and proof of what you supplied and when. Crucially, note the date you last supplied services or materials — this date often starts the preservation clock.
✅ You're done with this step when you can say, in one sentence, what you supplied, to whom, for which property, how much you're owed, and the date you last worked or delivered.
Phase 2 — Preserve the lien (Clock #1) 🔴
What happens: You formally preserve your lien. For most projects involving privately owned land, this means registering a claim for lien against the title to the property at the Land Registry Office. (For certain projects — for example, some public or Crown land, or condominium common elements — the rules differ and the lien may be given rather than registered. Confirm which applies.)
Who does it: You or your lawyer, through the electronic land registration system.
What you need: The legal description of the property, the owner's name, the amount owed, and the details of your supply. Accuracy matters enormously here (see pitfalls).
Timing: 🔴 As of 2026 the count is 60 days under the Construction Act, generally from a triggering event such as the last day you supplied services or materials, or the publication of a certificate of substantial performance of the contract. Which trigger applies to you, and on what date, is the part to verify immediately. Do not count on memory or an old article.
⚠️ Watch out: If you blow this deadline, your lien generally expires and cannot be revived. You may still have a contract or trust claim, but the security against the land — the part that gives you real leverage — is gone.
✅ You're done with this step when your claim for lien is registered on title (or properly given) before the deadline, with accurate property, party, and amount details.
Phase 3 — Perfect the lien by starting an action (Clock #2) 🔴
What happens: Preserving the lien is not enough on its own. You must then perfect it — start a court action to enforce it and register a certificate of action on title.
Who does it: Your lawyer (this stage is genuinely hard to do alone).
What you need: A Statement of Claim in the lien action and the certificate to register against title.
Timing: 🔴 There is a second strict deadline to perfect: as of 2026, 90 days under the Construction Act, running from the last day on which the lien could have been preserved — not from the day you actually registered it. Preserving early does not buy you extra time. Miss it and the preserved lien expires too.
Tip: Because Clock #1 and Clock #2 run back-to-back, lawyers usually calendar both the day a lien is preserved. The safest practice is to start early — don't wait until the project is fully finished if you're already not being paid.
✅ You're done with this step when the lien action is started and the certificate of action is registered on title within the perfection deadline.
Phase 4 — Know your holdback and trust protections
What happens: Two features of the Construction Act work in your favour even beyond the lien itself.
The statutory holdback. On most projects, each payer (owner, contractor) must hold back a percentage of the price of the work and keep it for a set period as a fund that liens can be satisfied from. This holdback is a key reason liens have teeth.
- As of writing, the holdback is a percentage of the contract/subcontract value held for a statutory period. Verify the current percentage and the release timing, since they're set by the Construction Act and can be affected by phased or annual release rules on larger projects.
Trust claims. Money received for a project is generally impressed with a trust for the benefit of those who worked on it. If someone up the chain receives payment for the project but doesn't pay you, they may be breaching trust — and individuals such as directors and officers can sometimes be personally liable. A trust claim is separate from the lien and is not lost just because a lien deadline passed — which makes it a valuable backup.
Who does it / what you need: You preserve evidence; your lawyer assesses both remedies. Keep records of payments made and received on the project.
✅ You're done with this step when you understand whether holdback funds exist for your project and whether a trust claim is available as a parallel route to recovery.
Phase 5 — Use prompt payment and adjudication (the faster lane)
What happens: Ontario's Construction Act includes a prompt-payment regime and interim adjudication designed to get money flowing during a project rather than years later in court.
- Prompt payment: Once a proper invoice is given, the payer generally must pay within a set timeframe, or deliver a notice of non-payment within a tight window explaining what they dispute. These steps are time-limited — verify the current periods.
- Adjudication: You can refer certain payment disputes to an adjudicator for a fast, interim, binding decision while the project continues. It's quicker and cheaper than a full trial, and the decision is enforceable (subject to limited review).
Who does it: You initiate; a lawyer or adjudication-experienced advisor helps you frame the dispute and meet the timing.
What you need: Your proper invoice, the contract, and a clear statement of the amount in dispute.
Tip: Prompt payment and adjudication run alongside lien rights — using them does not mean you give up your lien. Often the smartest play is to preserve your lien to lock in security and pursue adjudication to get paid quickly.
✅ You're done with this step when you've decided whether to refer the dispute to adjudication and have met any prompt-payment notice timelines.
Phase 6 — Resolve the claim
What happens: Most lien disputes settle. If yours doesn't, the lien action proceeds — these cases have their own streamlined procedure under the Construction Act, including motions and, ultimately, a trial of the lien.
Who does it: Your lawyer, with your input on strategy and numbers.
What you need: Patience and good records. Timing varies — confirm with counsel based on your court and the complexity of the project.
✅ You're done with this step when the dispute is settled (in writing) or the lien action is resolved by the court, and any payment or holdback is released to you.
Mistakes that quietly invalidate a lien
⚠️ Any one of these can sink an otherwise valid lien:
- Missing the preservation or perfection deadline. The number-one killer. Calendar both clocks.
- Lien too late or too early relative to substantial performance. The triggering event matters — get it right.
- Wrong property description or wrong owner. A defective registration can be challenged.
- Overstating the claim. Inflating the amount you're owed can expose you to costs and undermine credibility.
- Liening land you can't lien (some public/Crown land has special rules; you may need to give notice instead of registering).
- Assuming the old Construction Lien Act rules apply when your project falls under the modern Construction Act (or vice versa).
- Ignoring prompt-payment notice deadlines, then losing the fast route to payment.
- Letting trust evidence go cold — failing to track who received project money.
Mini-FAQ
Do I have to register a lien to get paid? No — you can simply demand payment, use prompt payment/adjudication, or sue on the contract. But a registered lien gives you security against the land, which is strong leverage. The catch is the deadlines.
The owner already paid the general contractor — can I still lien? Possibly. Lien and trust rights, and the holdback, are designed for exactly this situation. Get advice quickly.
I'm just a material supplier. Do I have lien rights? Often yes — suppliers of materials to an improvement can have lien rights under the Construction Act. Confirm based on your facts.
It's been a while since I finished. Is it too late? Maybe for the lien, but not necessarily for a trust or contract claim, which can run on different (longer) timelines. Don't assume — ask.
How Treadstone Law can help
Construction lien deadlines don't forgive delay — and that's exactly why early advice pays for itself. Treadstone Law is a digital-first Ontario firm that helps contractors, subcontractors, trades, and suppliers across the province protect lien rights, pursue trust claims, and use prompt payment and adjudication to get paid.
- Flat fees for many steps, so you know the cost before you commit.
- Fast online intake — get a lien assessment started right away.
- All-Ontario virtual service, office in Mississauga.
If you're not being paid, act now — the clock may already be running. Call 1-844-900-1070, visit treadstonelaw.ca/litigation, see treadstonelaw.ca/pricing, or treadstonelaw.ca/start-file today.
This is not legal advice
This guide is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.