A construction lien is a legal claim registered against a property that secures unpaid amounts owed to a contractor, subcontractor, or supplier. The lien preservation deadline is the last date on which that lien can be registered. After the deadline passes, the right to preserve a lien is permanently extinguished, regardless of how much money you are still owed. The deadline varies by province: Ontario is 60 days from last supply (Construction Act s.31), BC is 45 days (Builders Lien Act s.20), Alberta is 60 days general or 90 days for concrete-supply and oil/gas well work (PPCLA s.41), Saskatchewan is 40 days, Manitoba is 60 days (extended from 40 on April 1, 2024), Quebec uses a 30-day legal hypothec window (CCQ art. 2727), and the Atlantic provinces sit between 30 and 60 days. Most provinces also require a separate perfection step (court action plus Certificate of Action) within a longer window, typically 90 days more in Ontario.
Why it matters to Canadian contractors
- A registered lien gives you a secured interest in the property. It means the owner cannot sell or refinance without addressing your unpaid claim, which gives you significant leverage to collect.
- The lien deadline and the 28-day payment clock run simultaneously. If your Ontario project finished 50 days ago and you have not been paid, you have only 10 days left to preserve a lien even if you are still within your payment dispute period.
- Lien rights are a contractor's most powerful collection tool on construction projects, but they are also strictly time-limited. Courts will not extend the deadline for any reason.
- Registering a lien does not require a lawyer in most provinces, though legal help is advisable on any claim over a few thousand dollars. The registration itself is done at the land registry office.
Common mistakes and pitfalls
- The clock starts from the last day you supplied services or materials, not from the project completion date. If another subcontractor is still on site after you finish, their last day of supply does not extend your deadline.
- Supplying materials to a site counts as supply, even if you did not perform labour. Delivery of materials restarts the lien clock for you.
- In Ontario, the deadline is 60 days, not 45. The 45-day figure applies to BC and Alberta. Using the wrong number can result in missing your deadline entirely.
- A lien must be preserved (perfected) by starting a court action within a set period after registration, or the lien expires. Simply registering the lien is not the end of the process.
- Residential homestead exemptions in some provinces limit the enforceability of liens against a primary residence, though the registration right still exists.
Related
- Holdback calculator with lien timeline→
- Ontario Construction Act prompt payment guide→
- Glossary: Holdback→
- How the 28-day payment rule works→
This glossary entry is for general information only and does not constitute legal or tax advice. Canadian tax and construction law rules vary by province and contract. For advice specific to your situation, consult a licensed professional.