Prevention principle and time at large in Canada

The doctrine matters most in the gap between two things a Canadian contract does well: allocating named delay events, and barring late claims. Between them sits the act of prevention that the extension-of-time clause does not reach, and that is where the argument lives. Everything below is Canadian common law. Quebec runs a different system and is addressed only by way of contrast at the end.

A structural warning applies to every citation on this page and is not a formality. No Canadian judgment and no provincial statutory text was read in original form for the corpus behind this page. CanLII, the Supreme Court portal and the provincial e-laws sites all blocked automated retrieval. Case content rests on independent secondary sources that agree with one another. Check every judgment and every clause number against an authenticated source before pleading it. For the wider framework, start at extension of time in Canada.

What the prevention principle is, and what triggers it

The prevention principle is a default rule of contractual risk allocation: an owner that causes delay to the contractor's performance cannot then insist on the delay remedy it bargained for. Where the owner causes delay and no corresponding extension of time is granted, the liquidated damages clause becomes inoperative and time is at large. Where an extension is properly granted under the contractual mechanism, a new completion date is fixed and the liquidated damages entitlement revives.

Three things trigger it in practice. First, an owner act that delays completion and falls outside the events the extension-of-time clause covers, the classic gap identified in Peak Construction (Liverpool) Ltd v McKinney Foundations Ltd (1970) 1 BLR 111. Second, a breakdown in the operation of the mechanism: nobody appointed to certify, a certifier who refuses to operate the clause at all, or a clause too uncertain to work. Third, the absence of any completion date at all, which is rarer in an executed contract than in a letter of intent or a notice to proceed followed by heavy scope change.

It is a default, not an overriding rule of law, and clear express words displace it. That proposition is settled at appellate level in England. It has not been tested at appellate level in Canada on a bespoke amendment, and a Canadian court faced with drafting that expressly allocates owner-caused delay to the contractor would be deciding the point for the first time.

Perini Pacific. The Canadian anchor, and exactly how far it goes

The Canadian anchor is Perini Pacific Ltd v Greater Vancouver Sewerage & Drainage District, (1966) BCCA, affirmed [1967] SCR 189. It is the Canadian statement of the classical English rule and it remains the starting point for any prevention argument in a common-law province.

A building owner is not allowed to insist upon the penalty for delay if, by ordering extra, he has prevented the builder from completing the work by a specified time.

Note what that sentence does and does not do. It states the rule in its narrowest classical form (ordering extras, defeating a penalty) and it does so in a British Columbia appeal affirmed by the Supreme Court of Canada. It is not a modern restatement, it does not address concurrency, it does not address condition-precedent notice, and it does not set out a test for measuring the period during which the completion date is displaced. The companion Canadian authority, N.B.C. Mechanical Inc v A H Lundberg Equipment Ltd, 1999 BCCA 775, supplies the other half of the proposition: an owner cannot enforce liquidated damages where its own conduct caused the critical delay, but where the contract contains a valid extension-of-time clause that was properly operated, the owner may enforce liquidated damages from the extended date.

Both anchors are British Columbia cases. That is the single most important practical fact about the Canadian prevention principle, and it is developed below.

One case must not be added to that list. CIMIC Morningstar Investments Ltd v Chandos Construction Ltd, 2026 BCCA 2, is sometimes offered as a recent appellate statement of the doctrine. It is not. It is a decision refusing leave to appeal an arbitral award. It confirms curial deference to an arbitrator's contextual reading of a notice clause and to a prevention finding, it does not restate doctrine, and the underlying award is not public. Do not cite it as a Canadian appellate statement of the prevention principle.

The Perini no-damage-for-delay contradiction, stated openly

The corpus behind this page carries an unresolved conflict about Perini, and it is stated here rather than smoothed over. Alongside the prevention holding, one source attributes to a 1967 Supreme Court of Canada decision called "Perini" the enforcement of a no-damage-for-delay clause reading, in substance, that the contractor "shall have no claim or right of action against the Corporation for damages, costs, expenses, loss of profits or otherwise … by reason of any delay". That is almost certainly Perini Pacific, the same case. The register records the point as CONFLICT and directs that [1967] SCR 189 be read and the two propositions reconciled before either is restated.

The two do sit awkwardly together. A case that says an owner cannot insist on the delay penalty because it caused the delay, and a case that enforces a clause stripping the contractor of all delay damages, are pulling in opposite directions, though they are not strictly incompatible, since the prevention principle governs the owner's claim against the contractor and a no-damage-for-delay clause governs the contractor's claim against the owner. The safe formulation, and the one used on this page, is that Perini Pacific is a prevention-principle case in which an exculpatory delay clause was also in issue. Do not restate the no-damage-for-delay characterisation without reading the report.

The stakes are higher in Canada than a reader from the United States will expect, because there is no statutory prohibition on no-damage-for-delay clauses anywhere in Canada: federal, provincial or territorial. Canadian construction and lien statutes bar contracting out of the lien, trust and prompt-payment provisions and say nothing about delay-damages exculpation. No-damage-for-delay clauses are enforceable in Canada if clearly drafted. They fail on clarity, not on policy, and the governing framework is the three-stage exclusion-clause analysis in Tercon Contractors Ltd v British Columbia (Transportation and Highways), 2010 SCC 4. The Canadian battleground is stage one (construction and clarity) and the contractor's route is ambiguity plus the prevention principle, not public policy. See liquidated damages and the penalty rule in Canada.

The extension-of-time clause is the owner's answer, and CCDC 2's is narrow

An owner defeats a prevention argument by pointing to an extension-of-time clause that covers the act complained of. If the clause reaches the event, the completion date survives, an extension is assessed, and liquidated damages run from the extended date. That is why modern forms carry wide sweep-up provisions, and it is why the doctrine rarely succeeds where the drafting is competent.

The English authority puts it squarely: acts of prevention by an employer do not set time at large if the contract provides for extension of time in respect of those events, and an ambiguous extension-of-time clause is construed in favour of the contractor, Multiplex Constructions (UK) Ltd v Honeywell Control Systems Ltd (No 2) [2007] EWHC 447 (TCC). No Canadian appellate decision states either proposition in those terms, but the first follows from the contract itself and a Canadian court applying an operative extension-of-time clause will reach the same place.

CCDC 2 – 2020 is the standard Canadian form and is still current. There is no 2025 or 2026 update to CCDC 2. Its sweep-up is narrower than the international equivalents. GC 6.5.1 covers delay "by the Owner, the Consultant, or anyone employed or engaged by them directly or indirectly, contrary to the provisions of the Contract Documents". The qualifier does real work: the delay must be contrary to the Contract Documents, not merely attributable to the Owner. That is narrower than a JCT-style "any impediment, prevention or default by the Employer" and narrower than the FIDIC equivalent. GC 6.5.3.4: "any cause beyond the Contractor's control": is expressly time-only unless the delay in fact results from Owner or Consultant action, in which case it converts to a compensable GC 6.5.1-type claim.

The practical consequence is that the CCDC sweep-up leaves more room for an owner act to fall outside the machinery altogether than the English, FIDIC or NEC equivalents do. Whether that produces time at large in Canada, and how often, is under-litigated. And it is only ever a starting point: supplementary conditions almost universally amend GC 6.5, with the notable exception of the Ontario industry-agreed package, the OAA/OGCA Agreed-to Recommended Supplementary Conditions for CCDC 2 – 2020 contain no supplementary condition amending GC 6.5. Read the supplementary conditions before running any prevention analysis.

Comparative and jurisdictional. The English rows state appellate or first-instance authority of England and Wales. The Canadian rows rest on British Columbia and Ontario authority read from secondary sources only, no Canadian judgment was read in original form for this corpus.

Does "time at large" exist in Canada, and how thin is the authority

Yes, as a doctrine imported with the English common law: where there is no valid, operable completion date, the contractor's obligation becomes to complete within a reasonable time, the liquidated damages machinery collapses because there is no date from which to compute anything, and the owner is thrown back on proving general damages. What Canada does not have is much authority saying so.

Take the negatives in order, because they are more useful than a paragraph of hedging. There is no Ontario authority on the prevention principle or on time at large. Both Canadian anchors, Perini Pacific and N.B.C. Mechanical, are British Columbia cases. An Ontario contractor running the prevention defence is arguing on British Columbia and English authority, and should say so in the pleading rather than be caught by it on the other side's reply. There is also no Ontario construction liquidated-damages decision at all between 2018 and 2026 (the Ontario liquidated damages authorities are real-estate deposit, franchise and employment cases) so the remedy the prevention argument is aimed at is itself thinly evidenced in that province.

Two further limits are worth pleading around. Prevention is reached late in a Canadian dispute, because notice is reached first: a notice provision can bar a claim even without express "failing which" language (Corpex (1977) Inc v The Queen in right of Canada, 1982 CanLII 213 (SCC)), the owner need not prove prejudice (Technicore Underground Inc v Toronto (City), 2012 ONCA 597), and a CAD 4.1M claim was dismissed on summary judgment for missing a 10-working-day notice in Elite Construction Inc v Canada (Attorney General), 2021 ONSC 562, affirmed on appeal, though the appellate neutral citation reported for that affirmation is unverified in this corpus and appears only in a digest. In most Canadian delay disputes the prevention argument is never reached at all. See notice and time bars in Canada.

Quebec is the sharp contrast, and it is a contrast of consequence rather than of degree. The concept of time at large does not exist in Quebec at all. Where a term is indeterminate, article 1512 of the Civil Code of Québec requires the court to fix the term. Quebec's answer to temporal indeterminacy is judicial gap-filling. The common law's is to discharge the date. Nothing on this page should be extended to a Quebec contract, see Quebec versus common-law Canada on delay.

One further point should be modelled before time at large is pleaded in any common-law province, and it turns on the contract rather than on Canadian law. Where the liquidated damages rate also capped the contractor's delay liability, putting time at large removes the cap along with the clause and exposes the contractor to uncapped general damages for failure to complete within a reasonable time. For the doctrine in its jurisdiction-neutral form, see extension of time.

What a Canadian court does instead: apportionment, and the good-faith route

Where an English court would face a binary choice, a Canadian court apportions. Canadian courts have been willing to divide responsibility where multiple parties contribute overlapping delay, which orthodox English law does not do. That is an inference drawn from the authorities rather than a proposition any Canadian court has stated in those terms, but it is the single most important practical difference for an English or Australian practitioner running a Canadian job.

The evidentiary standard comes from Schindler Elevator Corp v Walsh Construction Company of Canada, 2021 ONSC 283, the leading Canadian concurrency authority: the postponement must be broken into its component parts so that time, responsibility and costs can be apportioned, with concurrency found where delays to co-critical and co-controlling activities overlap. Walsh Construction v Toronto Transit Commission, 2024 ONSC 2782, endorsed the same flexible approach and required a clear and rational expert opinion grounded in contemporaneous records. No Canadian appellate decision squarely on concurrent delay was located for 2024–2026, so this rests on first-instance authority. See concurrent delay in Canada.

The modern Canadian route runs through good faith, and it has no English equivalent. Bhasin v Hrynew, 2014 SCC 71, and C.M. Callow Inc v Zollinger, 2020 SCC 45, establish the duty of honest performance. Wastech Services Ltd v Greater Vancouver Sewerage and Drainage District, 2021 SCC 7, holds that a contractual discretion must be exercised reasonably and consistently with the purpose for which it was conferred. An owner assessing an extension-of-time application under CCDC 2 – 2020 GC 6.5 is exercising exactly such a discretion. An owner that sits on a valid application, or refuses it in bad faith, is therefore exposed to a claim in its own right rather than merely to a prevention defence. That argument has not yet been run in a reported Canadian delay case. It is structurally sound, it is uniquely available in Canada, and it is the most promising untested argument in this area.

Evidence carries the rest. The shape of a winning Canadian prevention case is owner design changes plus late approvals, actual owner knowledge evidenced through contemporaneous emails, meeting minutes and schedule updates, and a tribunal willing to read the notice clause in context. Each of those elements is evidential, not doctrinal, and the limit is set by Northland Kaska Corp v R, 2001 BCSC 929: "the grumblings of a contractor are not sufficient to constitute notice".

The qualifying-events interface, GC 6.5.2 versus GC 6.5.3

CCDC 2 – 2020 GC 6.5 allocates delay by cause, and the allocation decides money. GC 6.5.1 (Owner or Consultant delay contrary to the Contract Documents) and GC 6.5.2 (a stop work order issued by a court or other public authority) are compensable. GC 6.5.3 (labour disputes, fire and unavoidable casualties, abnormally adverse weather, and any cause beyond the Contractor's control) is time-only. Which limb an event falls into is usually where all the money is.

Form-default, CCDC 2 – 2020 printed general conditions. Supplementary conditions almost universally amend GC 6.5, so an executed contract may allocate differently. Clause numbers and headings rest on secondary sources. The printed text was not read in original form for this corpus.

The highest-value open question in the whole Canadian CCDC field sits inside that table. Whether a provincial public-health order is a "stop work order" under GC 6.5.2 has never been decided by a Canadian court. It matters because the answer decides compensable against time-only. The routing argument runs like this: in Porter Airlines Inc v Nieuport Aviation Infrastructure Partners GP, 2022 ONSC 5922 (a licence agreement, not a construction contract) the court held that "the pandemic itself is not the reason for the prevention of performance under a contract. Rather, it is the associated government and regulatory responses". If the operative cause is the order rather than the disease, the pandemic-relief argument must run through GC 6.5.2, which carries money, rather than through GC 6.5.3, which does not. The point is recorded as UNVERIFIED and expressly open. It will be litigated on the next public-health event. Plead GC 6.5.2 first and GC 6.5.3 in the alternative.

Three more negatives shape any GC 6.5.3 argument, and each should be stated to a client rather than hedged. No Canadian judgment holds COVID-19 to be force majeure under a construction contract at any point between 2020 and 2026, and no Canadian judgment applies GC 6.5.3 to the pandemic. No Canadian authority construes "abnormally adverse weather conditions" in GC 6.5.3.3, none defines the baseline against which "abnormal" is measured, and none endorses any proof method, so a Canadian weather claim is argued on a purely evidential footing with no domestic legal test, and the owner is free to attack both the baseline station and the normals period without contradicting any authority. No Canadian authority construes the GC 6.5.3.1 lock-out carve-in, and none defines "recognized contractors' association", which is doctrinally interesting, because that carve-in is an express contractual override of the "beyond the control of either party" principle in Atlantic Paper Stock Ltd v St Anne-Nackawic Pulp & Paper Co Ltd, 1975 CanLII 170 (SCC), [1976] 1 SCR 580, deeming the contractor's own association's decision excusable.

Tariffs and escalation: a money event under GC 10.1.2, not a time event

CCDC 2 – 2020 has no general materials-price escalation clause, but it does have a taxes-and-duties adjustment. GC 10.1.2 provides that any increase or decrease in costs to the Contractor due to changes in taxes and duties after the time of the bid closing shall increase or decrease the Contract Price accordingly. The correction matters because the commonly repeated statement that CCDC 2 contains no escalation mechanism at all is wrong.

The consequence for the 2025–26 supply shock is a routing rule, and it is the commonest Canadian claim error of the period. Tariffs imposed after bid closing are a priced-adjustment event under GC 10.1.2: a money event, not a time event. Claim the money under GC 10.1.2. Claim time separately under GC 6.5.3, and only if delivery was in fact delayed. Conflating the two loses both, because the time claim contaminates a straightforward price adjustment and the price claim invites the owner to say the contractor never proved delay to completion.

Force majeure will not fill the gap. Relief in Canada requires actual prevention of performance: supplies becoming more expensive is not enough, though supplies becoming unavailable may be. That follows directly from Atlantic Paper, whose control test and author-of-its-own-misfortune bar are where these claims die.

There is no help available from the institutions either. No CCDC or Canadian Construction Association guidance document, and no model supplementary condition, on tariffs or escalation was located, and there is no Canadian case law on tariff-driven escalation claims in construction for 2025–2026. Cost-plus forms push the risk the other way: under the CCDC cost-plus and construction-management forms, customs, taxes and duties paid during performance are included in the Cost of the Work and therefore sit with the owner.

À propos de ce contenu Le contenu de la bibliothèque est une information générale sur la pratique des réclamations de construction, et non un avis juridique. Le droit à réclamation, les délais et la procédure sont régis par votre propre contrat et par le droit du lieu où les travaux sont exécutés. Révisé le 8 août 2026 · Signaler une correction