Limitation periods and claim accrual in Ontario

The statutory clock is not the clock most contractors lose their claim on. A contractual claim procedure is a condition precedent to entitlement, and it is policed separately and much more strictly. That is the subject of the notice and time bars page. This page is about the Limitations Act, 2002: when the two-year period starts on a delay claim, what stops or postpones it, and what a contract can lawfully do to it.

Two things make Ontario worth a page of its own rather than a row in a national table. The first is section 22, which in a commercial construction contract is close to an unrestricted licence to rewrite the limitation period. The second is that Ontario has no bright-line accrual rule for delay claims at all, so the start date is argued case by case on discoverability. Everything below is stated as at August 2026, and (as with the whole of this Canadian cluster) no consolidated Ontario statutory text and no Ontario judgment was read in original form. The section numbers and holdings rest on independent secondary sources and should be checked before any limitation-critical step.

The basic period is two years from discovery, and discovery has four limbs

Ontario's basic limitation period is two years, running not from breach but from discovery. Section 4 of the Limitations Act, 2002 provides that "unless this Act provides otherwise, a proceeding shall not be commenced in respect of a claim after the second anniversary of the day on which the claim was discovered." Section 5 defines discovery, and section 15 imposes a fifteen-year outer limit that runs whether or not anything was ever discovered.

Section 5 is a four-limb test, and a claim is discovered on the day the claimant first knew, or a reasonable person in the claimant's circumstances ought to have known, that:

1. the injury, loss or damage had occurred
2. it was caused by an act or omission
3. the act or omission was that of the person against whom the claim is made and
4. "having regard to the nature of the injury, a proceeding would be an appropriate means to seek to remedy it."

The fourth limb is the one practitioners forget, and on a construction delay claim it is the one that does the work. It is not a question about knowledge of the loss at all. It asks whether litigation was yet a sensible response, and it is the doorway through which contractual dispute machinery (a mandatory mediation step, a staged negotiation, a referee's decision) enters the limitation analysis. A claim can be fully known and still not yet discovered within the meaning of section 5.

Section 15 sets the ultimate period at fifteen years from the day the act or omission on which the claim is based took place, regardless of discovery, with exceptions for minors, incapable persons and wilful concealment. On a construction project the ultimate period rarely bites, but it matters in two places: latent problems surfacing long after takeover, and section 22, which treats the fifteen-year period differently from the two-year one.

Because no consolidated statutory text was read for this corpus, the wording quoted above rests on converging secondary sources rather than on e-Laws. The substance is agreed across those sources. The exact quotation should be checked before it is put in a factum.

When an Ontario delay claim accrues: invoice, payment period, default

An Ontario delay or extras claim accrues on invoice-and-default discoverability, not on the delaying event and not at substantial performance. In 1838120 Ontario Inc v Township of East Zorra-Tavistock 2021 ONSC 3341 (Heeney J), the Superior Court held that a construction claim is discovered when three things have happened: an invoice has been issued within a reasonable time, a reasonable payment period has elapsed, and payment default occurs on the due date.

The facts are worth carrying because the margin was so thin. Road, sewer and sidewalk work was substantially concluded on 28 September 2015. The contractor sued in October 2017 for $134,502.71 in uncertified extras. The court fixed the reasonable invoicing time by reference to the contract and the parties' past practice, treated payment as due on 8 October 2015, and held that the limitation period began to run on 9 October 2015. The claim was statute-barred by roughly three weeks. The court also rejected the contractor's argument that each invoice generated its own separate limitation period. An argument that, if it had succeeded, would have produced a rolling series of clocks on a single running account.

UNVERIFIED No appellate history for East Zorra-Tavistock was located, so it is a first-instance decision and should be deployed as such.

Ontario has no bright-line accrual rule for delay claims. No Ontario appellate authority holds that a delay or prolongation claim accrues at substantial performance, at the final certificate, or at the delaying event. That is a recorded negative finding, not a gap in searching, and it cuts both ways: an owner cannot point to a fixed accrual date, and neither can a contractor. The analysis is discoverability, modified by the contractual claim procedure and by any contractual limitation clause.

For a practitioner arriving from a civil-law or a code-based regime the contrast is sharp. Quebec defers prescription on a construction claim until fin des travaux under article 2116 of the Civil Code, which gives a fixed and knowable start date. Ontario gives you an argument instead.

Negotiations do not toll, but mandatory staged ADR can postpone the start

Commercial negotiation does not stop the Ontario clock. East Zorra-Tavistock is explicit that ongoing payment negotiations do not toll the limitation period, which means a contractor waiting for a delay claim to be "resolved commercially" is running out of time while it waits. Mandatory staged ADR is different: it can postpone the day the clock starts, because it goes to the fourth limb of the discovery test rather than to tolling.

A tolling agreement does exist as an instrument, but the corpus records the threshold as high: an enforceable tolling agreement requires a clear and unambiguous request and an equally clear and unambiguous affirmative response (Markplan Inc v Osman), and mere forbearance does not suspend a limitation period (Hamilton v Metcalfe & Mansfield). This corpus carries no citation for either decision, and none is printed here. Both should be located before either proposition is relied on. The practical point survives the missing citations. A file note recording that "the parties are discussing the delay claim" is not a tolling agreement. Silence from an owner is not one either.

What can move the start date is a contractual step the contractor is obliged to take first. In PQ Licensing S.A. v LPQ Central Canada Inc 2018 ONCA 331 the Court of Appeal held that a mandatory mediation clause affects when a proceeding is an "appropriate means" to remedy the loss under section 5(1)(a)(iv), and therefore affects when the limitation period starts. That matters on standard construction forms. CCDC 2 – 2020 Part 8 imposes staged dispute resolution: notice of dispute within 15 Working Days of a decision, a response within 10 Working Days, 10 days to attempt amicable settlement, and 10 days to request a mediator where none was named at signature, and OPSS GC 3.13 and GC 3.14 impose staged negotiation and mediation before arbitration. On PQ Licensing, that staging can push out the discovery date for a delay claim, and it is the argument to run against an East Zorra-Tavistock attack.

The staging cuts a second way as well. J.P. Thomson Architects Ltd v Greater Essex County District School Board 2025 ONCA 378 held that a period stated inside a staged mediation clause. There, "within thirty (30) days": is a minimum, not a cut-off. Ontario therefore splits its rule of construction on contractual time limits: a notice-of-claim period is a condition precedent and is enforced strictly, while a period inside a staged ADR clause is a floor below which the process may not be short-circuited. Read together with PQ Licensing, the position is that a contractor is not penalised for working through mandatory ADR before issuing. The staging can delay the start of the limitation period, and the period stated in the ADR clause is not itself a bar. Neither case, however, converts ordinary commercial negotiation into a suspension of time.

Section 22, Ontario alone lets commercial parties shorten or exclude the period

Section 22 of the Limitations Act, 2002 starts from the position that a limitation period applies despite any agreement to vary or exclude it, and then opens exceptions that swallow the rule for commercial construction contracts. In a business agreement the parties may extend, shorten, suspend or wholly exclude the two-year basic period, and may vary even the fifteen-year ultimate period.

The operative subsections work as follows.

• s 22(1). The default: a limitation period applies despite any agreement to vary or exclude it, subject only to the exceptions in subsections (2) to (6).
• s 22(3) UNVERIFIED as to exact wording, a limitation period other than the section 15 ultimate period may be suspended or extended by an agreement made on or after 19 October 2006.
• s 22(4) UNVERIFIED as to exact wording, the section 15 ultimate period may be suspended or extended by such an agreement only if the relevant claim has been discovered.
• s 22(5): the exception that matters: in respect of business agreements, a limitation period may be varied or excluded by an agreement made on or after 19 October 2006, and the ultimate period may be varied in a business agreement, though suspended or extended only in accordance with subsection (4).
• s 22(6). The definitions that make it work: a "business agreement" is an agreement made by parties none of whom is a consumer as defined in the Consumer Protection Act, 2002, and "vary" includes extend, shorten and suspend.

A construction contract between commercial parties will almost always be a business agreement. The only true floors are that the ultimate period may be suspended or extended only after the claim has been discovered, and that the presence of a consumer party voids the business-agreement exception entirely. On the second point the corpus records that Ontario courts read "parties" broadly and purposively to protect individuals (Kassburg v Sun Life), and that an agreement which is not a genuine business agreement cannot contract out of the Act at all (Thompson v Sun Life. Parmar v Teachers Life). This corpus carries no citation for any of those three decisions, and none is printed here.

Jurisdictional comparison. The Ontario column is statute. The Quebec column is article 2884 C.c.Q. Both rows rest on secondary sources: no consolidated Ontario statutory text was read for this corpus, and no Canadian judgment was read in original form.

The consequence for a delay claim is concrete. An Ontario owner's supplementary conditions can lawfully impose, for example, a one-year-from-substantial-performance bar on all delay claims, and it will bind. The identical clause in a Quebec contract is a nullity. Two provinces of one federation, opposite answers, which is why the first document to read in an Ontario delay file is not the general conditions but the supplementary conditions, looking for a limitation clause.

The Leveque three-part test, how these clauses are drafted wrong

Section 22 permits the clause. It does not save a badly drafted one. In Ontario (Transportation) v J & P Leveque Bros Haulage Ltd 2025 ONCA 573 (an MTO Highway 60 rehabilitation contract, so it doubles as public-works authority) the Court of Appeal reversed a finding that the contract had validly substituted its own limitation period, because the clause did not clearly describe the limitation period, identify its scope, and exclude the statutory periods.

The contract required a notice of protest and ADR, and required litigation within two years of the contract's completion date. The motion judge held that the contract was a section 22(6) business agreement that had validly substituted that period for the statutory one. The Court of Appeal disagreed: the statutory two-year period governed, and the action (commenced within two years of the contractor receiving the referee's decision) was not barred.

The three-part test. A contractual limitation clause must

1. use clear language describing a limitation period
2. identify the scope of its application. And
3. exclude the operation of the statutory limitation periods.

It must be, in the Court's phrase, "unambiguous, clear in language and scope". A clause that merely says proceedings "shall be commenced within two years of completion" does limb one and part of limb two, and fails limb three outright, which is why so many owner-drafted clauses collapse. A compliant clause has to say what the period is, what claims and what parties it catches, when it starts and by reference to what event, and that it applies instead of and to the exclusion of the periods in the Limitations Act, 2002, including where relevant the section 15 ultimate period.

There is a structural oddity in Leveque worth carrying separately, because it recurs in owner drafting. On the contract's own terms the referee's decision issued more than two years after the completion date, so a literal reading of the clause would have extinguished the claim before it could be brought. The Court read the clause down to avoid that absurdity. Any clause that runs a limitation period from a fixed project milestone while also requiring the contractor to exhaust a dispute process of indeterminate length carries the same defect.

The first document to read in an Ontario delay file is the supplementary conditions, looking for a contractual limitation clause. The second question is whether it satisfies the Leveque test, and a defective one leaves the two-year statutory default standing, which is usually what the contractor wants.

What changes at a provincial border

Contractual variation of a limitation period is the sharpest divergence in Canadian construction law, and Ontario sits alone at one end of it. Alberta, Saskatchewan and Manitoba permit extension only, British Columbia's statute is silent, Quebec permits nothing, and for the Atlantic provinces and the territories the corpus found no source at all.

Jurisdictional comparison, statute-level. The Alberta, Saskatchewan and Manitoba rows are the provincial limitations statutes. The British Columbia row rests on Rosas v Toca and is marked unverified. No provincial statutory text was read directly for this corpus, and lien and limitation figures must be checked against the statute before any limitation-critical use.

The basic and ultimate periods themselves are only verified in three jurisdictions. Ontario is 2 years from discovery with a 15-year ultimate period. Alberta is 2 years from knowledge of the injury, its attribution and that proceedings are warranted, with a 10-year ultimate period running from the discrete, first actionable breach rather than on any continuing-conduct theory. Quebec is 3 years under article 2925, and the clock does not start until fin des travaux under article 2116. For British Columbia, Saskatchewan, Manitoba, Nova Scotia, New Brunswick, Prince Edward Island, Newfoundland and Labrador and the territories the periods are unverified. The common pattern is a two-year basic period and ultimate periods somewhere between ten and thirty years, but those are working assumptions and should not be populated from memory. The provincial comparison page sets out what else changes at the border, and the Canadian hub carries the pan-Canadian doctrine that sits behind all of it, including the recorded negative finding that no Canadian province or territory has a statute addressing construction delay claims as such.

The arbitration trap, issuing in court may not stop time

Limitation periods apply to arbitrations. Where an arbitration clause governs the dispute, issuing a claim in court may not stop the clock, which means the familiar protective step of filing a statement of claim "to protect the limitation" can protect nothing at all. On a CCDC 2 project running the CCDC 40 – 2018, Rules for Mediation and Arbitration of Construction Disputes arbitration route, the step that has to be taken in time is the step that commences the arbitration.

The authority the corpus carries is Lafarge Canada Inc v Edmonton (City) 2013 ABCA 376. Two qualifications belong in the same sentence as the proposition. It is an Alberta appellate decision, and this corpus carries no Ontario authority to the same effect, so on an Ontario project it is persuasive, not binding. And it does not follow that court proceedings are always futile. What follows is that the question of which forum the limitation period is satisfied in has to be answered before the period expires, not after.

The point is sharpened by the fact that Ontario's staged forms drive disputes towards arbitration. CCDC 2 – 2020 Part 8 and the OPSS GC 3.13 and GC 3.14 sequence both terminate in arbitration rather than litigation, and Infrastructure Ontario and Metrolinx project agreements all contain bespoke arbitration regimes. A contractor two months from the end of a limitation period on a CCDC 2 contract should be asking whether a notice of arbitration, not a statement of claim, is the instrument that stops time.

A related question is expressly open: no Ontario authority decides whether an arbitration clause ousts statutory adjudication. The scheme implies that it cannot be contracted out of. A party "may" refer, and section 4 of the Construction Act bars waiver, but it has not been decided, and it affects every Infrastructure Ontario and AFP project. See the Ontario prompt payment and adjudication page.

Three clocks that are not limitation periods, and one question nobody has answered

Section 22 reaches the limitation period and nothing else. The 90-day adjudication window, the 60-day and 90-day lien periods and contractual notice periods are not limitation periods, are not governed by the Limitations Act, 2002, and cannot be varied under section 22. They are different instruments with different characters in law and different consequences for missing them.

Jurisdictional, statute-level, save the third row which is form-default. The adjudication and lien rows are section 13.5(3) of the Construction Act and the lien provisions as amended with effect from 1 January 2026. The 60-day and 90-day lien periods were unchanged by the 2026 amendments. Form-default rows describe the published CCDC 2 – 2020 text and are displaced by the executed contract and its supplementary conditions. No consolidated statutory text was read for this corpus.

Date-stamp the adjudication row before using it. Ontario runs three date-keyed regimes: contracts before 1 July 2018 under the former Construction Lien Act with no prompt payment and no adjudication, contracts from 1 July 2018 to 31 December 2025 with adjudication available but time not adjudicable, and contracts on or after 1 January 2026 under the full regime, in which an extension of time became adjudicable as an ancillary head where reasonably necessary, but not on P3 projects. In August 2026 nearly every Ontario project with a mature delay claim sits in the middle band.

UNVERIFIED The open question. Whether a contractual limitation clause valid under section 22 can also cut down (or extend) the 90-day adjudication window under section 13.5(3) has not been decided. Logically section 13.5(3) is a precondition to a statutory remedy rather than a limitation period, so section 22 should not touch it. But the Construction Act itself contains an express power for the parties to extend that window by agreement, and that express power invites the argument that the window is contractually malleable and so open to being shortened by a well-drafted supplementary condition too. The argument is available in either direction and there is no authority on it.

The interface is where most claims are actually lost, and it is worth stating in the negative, because the intuition runs the wrong way in each case.

Every one of those deadlines, with its trigger and its source, is set out on the Ontario delay claim clocks page. The wider Ontario position on time is on the Ontario extension of time hub.

About this material Library content is general information about construction claim practice, not legal advice. Entitlement, deadlines and procedure are governed by your own contract and by the law of the place the work is performed. Reviewed August 8, 2026 · Report a correction