The 'Mechanic's Lien' in Ontario: It's a Construction Lien — Here's the Process

First, the terminology — Ontario says construction lien

"Mechanic's lien" is the older term still used in much of the United States and in older Canadian materials. Ontario retired it decades ago: the modern statute is the Construction Act, and the remedy is the construction lien. If you are reading American guides about notarized lien affidavits and county recorders, put them down — none of that procedure applies here.

The good news: what you are trying to do — secure payment for work or materials against the property you improved — works in Ontario, and arguably with more structure, through preservation, perfection, holdback and prompt payment.

The Ontario process at a glance

• Supply work or materials that improve the premises — this creates the lien right
• Preserve the lien, generally within 60 days of your trigger date, by registering a claim for lien on title
• Perfect the lien within the following 90-day window by starting a Superior Court action (and registering a certificate of action where required)
• Look to the 10% statutory holdback each payer must retain
• Consider prompt-payment notices and ODACC adjudication for a faster interim decision

Where imported (US) assumptions break Ontario claims

Three imported mistakes appear constantly: waiting for a "notice of completion" that Ontario does not use the same way; assuming a one-year filing window when Ontario's preservation period is measured in days; and sending a US-style "preliminary notice" instead of registering a claim for lien. Every one of these can cost the entire lien right.

If your project, contract or dispute has any complexity — multiple payers, terminated contracts, disputed last-supply dates — get Ontario advice on your actual trigger dates rather than guessing.

Talk through your dates before they expire

Bring the contract, the invoices and a timeline to a consultation. The first 15 minutes are free, we confirm the deadlines that apply to your role in the chain, and defined steps like preserving the lien are quoted flat.