Construction lien law protects the people who supply labour and materials to a project — contractors, subcontractors, suppliers — by giving them a claim against the property if they are not paid. Because property law and civil procedure fall under provincial jurisdiction in Canada, each province has its own statute governing this, and the details genuinely differ: the holdback percentage, how long a lien claimant has to register their claim, and how and when the holdback can be released.
This matters directly to a construction mortgage file because the holdback affects how much money is actually available to the contractor at each stage, and because an unresolved lien registered against the property is a title problem the lender will not fund through and the borrower cannot easily sell or refinance around. A broker working construction files needs to know which province's rules apply to a given deal — quoting Ontario's regime on an Alberta file, or vice versa, is a real and avoidable error.
Ontario's statute — renamed the Construction Act after a substantial 2018 overhaul of the former Construction Lien Act — requires every payer on a project to hold back 10% of the value of work or materials as they are paid for. That 10% is the security fund available to lien claimants if someone downstream does not get paid. A contractor or subcontractor has 60 days from the relevant triggering date to preserve a lien by registering it, with a further period to perfect it through court action.
Amendments that took effect 1 January 2026 changed how that holdback is released rather than the percentage itself: annual release of accrued holdback is now mandatory on contracts running longer than a year, with the owner required to publish a notice and then release the holdback within a set window afterward, provided no lien has been preserved. The 10% figure has not changed. Anyone working from pre-2026 Ontario training material should specifically check the annual-release mechanics, since that part of the law moved.
BC's Builders Lien Act also sets a 10% holdback — the greater of the value of work or material actually provided, or any payment made on account. Where BC differs is the lien filing window: a claim of lien must be filed no later than 45 days after a certificate of completion is issued, or 45 days after the head contract is completed, abandoned or terminated if no certificate exists. The holdback itself typically cannot be released until roughly 55 days after that triggering event — a deliberate buffer that covers the 45-day filing window with a margin, so the owner is not releasing money while a lien could still legally land.
The lesson for a broker is not to assume Ontario's 60-day figure applies in BC. It does not — BC's window is shorter, and its holdback-release timing is built around a different completion trigger.
Alberta's current regime — the Prompt Payment and Construction Lien Act, in force since 29 August 2022 for new contracts — also sets a 10% holdback, but pairs it with a strict prompt-payment timeline that Ontario and BC do not have in the same form: an owner must pay a contractor within 28 calendar days of receiving a compliant "proper invoice," and a contractor must in turn pay its subcontractors within 7 calendar days of being paid, with a formal 14-day window to dispute an invoice rather than simply not pay it. Large, multi-year projects over $10 million can access phased or annual holdback release similar in spirit to Ontario's mechanism.
The prompt-payment machinery is the distinguishing feature of Alberta's Act relative to Ontario and BC, and it is worth knowing exists even on a residential construction file, since a borrower acting as their own general contractor is stepping into the role the Act regulates.
Quebec does not use lien law in the common-law sense at all. Under the Civil Code of Québec, a person who has taken part in the construction or renovation of an immovable — architects, engineers, material suppliers, workers, contractors and subcontractors — benefits from a legal hypothec of construction, which secures the increase in value their work added to the property. This hypothec exists automatically for 30 days after the end of the work even without registration; to preserve it beyond that window, the claimant must register a notice in the Quebec land register (the registre foncier) and serve it on the owner within that same 30-day period.
There is no statutory holdback percentage in Quebec's regime comparable to Ontario, BC or Alberta's 10% — the mechanism protects the claimant through the hypothec itself rather than through a required cash retention. A Quebec construction file needs its own review by counsel or a notary familiar with the Civil Code; nothing in the common-law provinces' approach transfers directly.
Manitoba, Saskatchewan, Nova Scotia, New Brunswick, Newfoundland and Labrador, and Prince Edward Island each have their own builders' lien or mechanics' lien legislation, with holdback percentages and filing periods that are not identical to Ontario's, BC's or Alberta's. Rather than guess at figures for provinces not covered above, the discipline to build is: never assume, always confirm the specific province's current statute — or have counsel confirm it — before advising a client on holdback or lien timing outside the four provinces detailed here.
A broker tells an Alberta client that their contractor's lien rights expire if not registered within 60 days, and that a 10% holdback applies — using what they learned about Ontario. What is wrong with this advice?
Alberta's Prompt Payment and Construction Lien Act does set a 10% holdback like Ontario, so that specific number happens to transfer here — but that is coincidence, not a rule, and the broker got lucky rather than being right for the right reason. The real gap is Alberta's separate prompt-payment machinery (28-day owner payment window, 7-day subcontractor payment window, a 14-day dispute window) that has no Ontario equivalent, and which a broker who simply assumed Ontario's rules applied would have missed entirely. Construction lien law is provincial, not federal, which is the whole reason this kind of copy-paste advice is risky.
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