Most craftsmen who've been stiffed on a job think their only real options are "ask nicely again" or "write it off." Ontario's Construction Act gives you more than that, whether you ever use it or not — and knowing the shape of that right matters even on a job where you never come close to needing it, because the clock on it starts ticking the moment the work does, not whenever the dispute actually starts.
The right you already have, on every job
Anyone who supplies services or materials to an improvement on a property — a renovation, a repair, an installation — has a potential construction lien against that property for what they're owed, up to the value of what they actually supplied. You don't need to register anything in advance for this right to exist; it's there from the first day you show up with tools. What you do need is to act inside a real deadline once a payment dispute turns serious, which is the part most tradespeople never look up until they need it.
The 10% holdback that shapes what "final payment" even means
Whoever is paying for the work — a homeowner, a general contractor, whoever is one step up the chain from you — is required to hold back 10% of the price of the services or materials as they're actually supplied, for the length of the lien period. That holdback exists specifically as security for lien claims, which is why a client paying you "everything except 10%" on a larger job isn't automatically shorting you; it may be exactly what the Act requires them to do until the lien window closes. On a contract running longer than a year, 2026 changes make releasing that accrued holdback mandatory on each contract anniversary rather than optional, with a notice published and payment due on a set schedule afterward — not something most single-visit repair jobs ever reach, but worth knowing if you're doing renovation-sized work with a payment schedule attached to it.
The clock that actually kills the right if you miss it
This is the part that costs people their leverage without them realizing it. You generally have 60 days to preserve (register) a lien, counted from the relevant trigger — typically the last day you actually supplied services or materials, or from substantial performance, completion, abandonment, or termination of the contract. Miss that window and the lien right itself is gone, even though the client may still legally owe you the money. If you do preserve it in time, you then have 90 more days to perfect it — actually take the claim to court — before that right lapses too. Add it up and you have roughly five months from the triggering event to act, which sounds generous until you remember most people spend the first several weeks of a payment dispute just hoping it resolves on its own.
When this is actually worth doing — and when it isn't
A lien is a real legal process with real legal cost, and it's not the right tool for every unpaid invoice. Registering one against someone's house over a $400 faucet repair rarely makes financial sense once you weigh the legal fees against what's owed — small claims court, a collections process, or simply knowing when to cut your losses is usually the more practical move at that scale. Where it becomes genuinely worth knowing is on larger renovation-sized work, where the unpaid amount is large enough that the legal process pays for itself, and where a client who knows you understand your real rights is more likely to settle before it gets that far in the first place.
What this means before a dispute ever starts
The deadline above only works in your favour if you know when it started, which means knowing your own last day of supply on every job — not a rough guess reconstructed after the fact. The same record-keeping that protects you in a warranty dispute protects you here too, and a clear, written scope from the start — the same discipline covered in pricing a job fairly — is what makes "what was actually owed" a short conversation instead of a long one. None of this requires expecting the worst from every client. It just means the handful of times a year it actually matters, you're not starting from zero.
Know the clock, even if you never need it
Most jobs end with a handshake and a paid invoice, and this whole page stays irrelevant to them. The value of knowing it is entirely in the jobs that don't go that way — knowing you have 60 days, not "eventually," and knowing a lien is a real tool for a real-sized dispute rather than a bluff, changes how a hard conversation with a non-paying client actually goes.