What does it mean to perfect a construction lien and what happens if a contractor misses the deadline in Ontario?

Perfecting a lien is the second step in enforcing a construction lien under the Construction Act, after preserving it. Preservation registers the claim against the property's title; perfection means actually starting a court action to enforce the lien and registering the required certificate of action on title, which must happen within 90 days after the last day the lien could have been preserved. Perfection is what keeps the lien alive as an enforceable claim rather than a registration that simply expires.

If the perfection deadline is missed, the lien generally expires and is no longer enforceable against the property, even though it was validly preserved in the first place - this is a common and often devastating mistake, since a lienholder may believe registering the initial claim was the hard part done, only to lose the entire remedy by not following through with a court action in time. The underlying contract debt can typically still be pursued as an ordinary lawsuit, subject to the general limitation period, but the powerful security the lien provided against the specific property is lost once perfection is missed. Given how unforgiving this second deadline is, calendaring it the moment a lien is preserved is essential.