Ontario's Construction Act Liens: Key Questions Answered

What a construction lien is

A construction lien is a charge against the land itself, securing payment for those who supply services or materials to an improvement — contractors, subcontractors, suppliers and certain consultants. Because the lien attaches to the owner's title, it is one of the most powerful collection tools in Ontario construction, and one of the most deadline-sensitive.

The deadlines that decide everything

Under the modernized Construction Act, a lien must be preserved — registered against title (or given to the owner, for certain public projects) — within 60 days of the trigger date, which is generally publication of the certificate of substantial performance or the date of last supply, depending on the situation. It must then be perfected by starting a court action (and registering a certificate of action where required) within 90 days after the last day it could have been preserved.

Miss either window and the lien expires. No court can revive it — the claim survives only as an ordinary contract debt, without the leverage of the owner's land.

Holdback in one paragraph

Everyone paying on a construction contract must retain a 10% holdback from each payment. That fund is what lien claimants below them in the construction pyramid can look to. Owners who pay out without retaining holdback can end up paying the same money twice — see our companion guide on holdback requirements.

If a lien has been registered on your property

• Do not ignore it — a preserved lien blocks refinancing and sales, and a perfected lien is active litigation
• Check the deadlines first: an expired lien can be discharged
• Consider vacating the lien by paying security into court, which frees the title while the dispute continues
• Gather the contract, invoices, payment records and correspondence before your consultation