A builders lien (called a construction lien in Ontario and a mechanics lien in some older statutes) is a legal charge you register against the property you worked on when you have not been paid. It ties your unpaid claim to the land itself, so the owner cannot easily sell or refinance until the debt is dealt with. It is the single most powerful tool a Canadian tradesperson has for getting paid, but it is governed by strict deadlines that, if missed by even one day, wipe out the right permanently. Quebec is the exception: it has no lien, it has a legal hypothec, which works differently and is covered at the end.
How a lien secures your money
When you supply work or materials to an improvement on land, the lien legislation in your province gives you a claim against that land for the value of what you supplied, even though you have no contract with the owner. Subcontractors and suppliers at every tier have this right, not just the prime contractor. The lien attaches to the property and, in most provinces, also to the holdback fund the owner is required to keep back (see The Statutory Holdback Explained).
A registered lien clouds the title. That is what gives it teeth: an owner who wants to sell, or a lender who wants to advance the next draw, will usually make sure you are paid or that the lien is bonded off (replaced with security) so the project can proceed.
Preservation versus perfection: two separate steps
This is the part people get wrong. Securing a lien is a two-stage process, and both stages have deadlines.
- Preservation is registering the lien on title (and in some provinces serving it) within the short statutory window after your last day of work. This is the deadline that ranges from 30 to 90 days depending on the province. Miss it and the lien is gone.
- Perfection is starting a court action to enforce the lien (and, in several provinces, registering a certificate of pending litigation) before a second, later deadline. Preserving but failing to perfect also kills the lien.
In Ontario, you preserve within 60 days and perfect within a further 90 days. In British Columbia there is no short perfection window: a preserved lien lasts one year from filing, but you must start a court action and file a certificate of pending litigation within that year. The exact numbers per province are in Lien Deadlines by Province.
The holdback connection
Most provinces require every payer in the chain to hold back a percentage of each payment (commonly 10 percent, 7.5 percent in Manitoba) as a fund for the trades below. Your lien attaches to that holdback. Even if the owner has paid the general contractor in full, the holdback is meant to still be there for you, which is why understanding both the lien and the holdback together is what protects you.
What counts, and the deficiency trap
A lien covers the value of the work and materials you actually supplied to the improvement. It does not cover damages for delay or lost profit, which is a court matter. A dangerous trap: going back to fix a deficiency or do minor remedial work after the job is substantially complete does not reset or extend your lien clock. The courts are strict. Date your true last day of substantial supply and count from there, not from a later snag-list visit.
Quebec is a separate animal: the legal hypothec
Quebec has no builders lien. The equivalent is the legal hypothec of construction under the Civil Code of Quebec (articles 2726 to 2732). Two things make it different. First, if you do not have a direct contract with the owner (most subcontractors and suppliers), you must serve the owner a prior written notice describing your contract before you start work, or you lose hypothecary rights for everything done before the notice lands. Second, the timeline runs from the end of the entire project, not your own last day: you register and serve within 30 days of completion of the work, and you have 6 months to bring an action. There is no mandated holdback in Quebec.
Common mistakes
- Counting from a snag visit. Going back to fix a deficiency does not extend the clock. Count from your last day of real supply.
- Preserving but never perfecting. Registering the lien is only half the job. Diary the perfection deadline too.
- Assuming you have a lien in Quebec. You have a hypothec, with a prior-notice requirement that catches out-of-province subs cold.
- Waiting for adjudication to finish. Adjudication does not pause the lien clock. Preserve the lien anyway, in parallel.
Common questions
How long do I have to file a lien?
It depends on your province, and the clock runs from your last day of work or last supply of materials. Deadlines range from about 30 to 90 days (for example 60 days in Ontario, 45 in BC, 40 clear days in Saskatchewan). Miss it by a day and the right is gone, so diarise it the moment you finish.
Do I lose my lien rights if the contract waives them?
In most provinces a pre-emptive waiver of lien rights is unenforceable, because the right is protected by statute. Quebec uses a legal hypothec rather than a lien. Confirm your own province's rule before relying on a contract clause.
Can I lien a private home I worked on?
Generally yes. A builders lien attaches to the property you improved, including a private home, subject to your province's rules. Registering it clouds the title, which is what gets you paid.
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