Substantial performance is the statutory milestone, defined in section 2 of the Ontario Construction Act, at which a construction contract is considered essentially complete. A contract is substantially performed when the improvement is ready to be used (or is being used) for its intended purpose and the cost to correct or complete the remaining work is within set limits: 3% of the first $1,000,000 of the contract price, 2% of the next $1,000,000, and 1% of the balance. Reaching substantial performance lets the contractor publish a certificate of substantial performance, which is the event that starts the 45-day lien-expiry window on the accrued holdback and triggers the release timeline for the statutory holdback.
Why it matters to Canadian contractors
- Publishing the certificate of substantial performance starts the clock for releasing the 10% statutory holdback. Until it is published and the lien period runs out, the holdback stays withheld.
- It is the trigger date for lien rights on the work done up to substantial performance. Subcontractors who supplied before that date measure their lien deadline from the certificate's publication.
- Misjudging substantial performance can mean billing for holdback release too early (before the lien window closes) or too late (leaving your money tied up longer than the statute requires).
- On larger ICI contracts the certificate is published and posted publicly. Knowing when it has been certified tells every subcontractor on the job when their own clocks start.
Common mistakes and pitfalls
- Substantial performance is not the same as total completion. Minor deficiencies can remain; the test is readiness for use plus the cost-to-complete thresholds, not a perfect punch list.
- The percentage thresholds are tiered, not a flat percentage of the whole contract. Applying a single 3% to a large contract gives the wrong answer.
- Holdback is released after the lien period following certification expires, not on the certification date itself.
- Provinces outside Ontario use their own substantial-performance or substantial-completion definitions and thresholds. Do not assume the Ontario numbers apply elsewhere.
Related
- Glossary: Statutory holdback→
- Glossary: Construction lien deadline→
- Holdback calculator→
- Ontario Construction Act guide→
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.