Extension of time

The elements a claim must establish are the same everywhere. Their content is not. Under JCT Design and Build 2024 the qualifying event is a Relevant Event and the notice carries no fixed deadline, under FIDIC Red Book 2017 (reprinted 2022) it is a Sub-Clause 8.5 ground and the notice is a 28-day time bar, under NEC4 Engineering and Construction Contract there is no extension of time clause at all, and time relief arrives only as a change to the Completion Date through the compensation event machinery. Same skeleton, different animal.

This page sets out that skeleton, compares how seven standard forms and five jurisdictions fill it in, and routes to the detail. Every table below states form-default positions. Bespoke amendment to extension of time and concurrency provisions is the norm on major projects, and an analysis run against the published form rather than the executed contract is a starting point, not an answer.

What an extension of time actually does

An extension of time moves the contractual date for completion. Its function is defensive, not compensatory: it relieves the contractor of liability for delay damages up to the extended date, and it protects the employer just as much, by preserving a valid and ascertainable date from which those damages can run (SCL Delay and Disruption Protocol, 2nd Edition (February 2017), Core Principle 2).

That second half is the part contractors underweight. An employer who refuses a plainly justified extension is not protecting its liquidated damages. It is putting them at risk, because in several jurisdictions a completion date the employer itself has prevented the contractor from meeting is a date the employer can no longer levy damages from.

Time and money are separate gateways. Entitlement to an extension does not carry entitlement to compensation, and entitlement to compensation does not depend on an extension having been granted (SCL Protocol, 2nd Edition (February 2017), Core Principle 12). FIDIC Red Book 2017 (reprinted 2022) Sub-Clause 8.5 is the cleanest illustration: it confers no payment entitlement of itself, and its grounds for exceptionally adverse climatic conditions, for Unforeseeable shortages and for Employer delay give time only under the standard form. Treating "excusable" and "compensable" as the same word is an expensive vocabulary error. What the extra weeks are worth, and which of them are recoverable at all, is worked separately under prolongation and delay costs.

The four elements a time claim has to establish

Every extension of time regime tests the same four things. The elements are invariant, their content is contractual. Miss any one and the submission is arguable, miss the notice window and on most forms none of the other three matters.

Inferential: the four-element frame is the corpus's own synthesis of what the regimes have in common, not a scheme any one form sets out.

Two propositions hold across all of them and are worth stating before anything else.

Delay to progress is not delay to completion. Only delay to completion generates an extension (SCL Protocol, 2nd Edition (February 2017), Core Principle 6). Delay that consumes float on an activity that had some is disruption, and disruption is a different claim under a different clause. This is the single most-abused distinction in the field, and, across the decisions gathered in this corpus, it is where claims most often fail: in George Sollitt Construction Co. v United States, 64 Fed. Cl. 229 (2005), delay affecting only non-critical activities did not delay completion.

Assessment is net, not gross. Where a qualifying event occurs during a period of culpable contractor delay, the extension is fixed by adding the delay caused to the previously fixed completion date, not by re-fixing completion by reference to the date of the instruction. That is Balfour Beatty Building Ltd v Chestermount Properties Ltd (1993) 62 BLR 1 (Colman J), the "dot-on, dot-off" method: governing in England and widely followed elsewhere. The BLR reference is taken from secondary sources in this corpus and has not been checked against the report itself. A contractor already twelve weeks late who receives a two-week variation gets two weeks, not fourteen.

What your contract calls these things

Vocabulary is regime-specific, and using the wrong word signals to the other side that the claim was not written by someone who has read the contract. The concepts map across forms. The names do not.

Form-default. Terminology and clause references are read off the published forms. Bespoke amendment is normal on major projects, and the executed contract governs.

Under NEC4 there is no extension of time clause. A reader who searches an NEC4 contract for one will not find it, and a claim drafted in extension-of-time language will be answered in compensation-event language. Time and money move together through a single mechanism, assessed prospectively from a quotation, which is a materially different commercial animal from the JCT and FIDIC structure, where the time claim and the money claim run on separate tracks and can succeed or fail independently.

Element 1, which events qualify, and which of them pay

The qualifying event is rarely where a claim fails, because three of the forms in the table below carry a genuine sweep-up: AIA A201–2017 §8.3.1, FAR 52.249-10(b) and CCDC 2 – 2020 GC 6.5.3.4. JCT and FIDIC do not, and NEC4's cl 60.1(19) is a higher bar than a sweep-up, so on those three forms element 1 is worth checking rather than assuming. It is, however, where a contractor most often prices the wrong risk, because the list of events that give time is not the list of events that give money, and the two lists diverge differently in every form.

T = time only. T+M = time and money. Form-default positions: bespoke amendment to these provisions is normal on major projects, and the executed contract governs.

Three structural points follow from that grid, and each of them contradicts something practitioners routinely assume.

FIDIC's sweep-up is narrower than it looks. Sub-Clause 8.5 of the Red Book 2017 (reprinted 2022) has no general "any cause beyond the Contractor's control" limb at all. Ground (e) covers Employer conduct, ground (d) covers Unforeseeable shortages arising from epidemic or governmental action, and ground (c) covers climate. Everything else has to arrive through ground (b), the cross-reference to a specific Sub-Clause. If no Sub-Clause applies, there is no extension. AIA A201–2017 §8.3.1, FAR 52.249-10(b) and CCDC 2 – 2020 GC 6.5.3.4 all carry a genuine sweep-up. FIDIC does not.

The JCT 2024 opt-in is the most commercially significant change in the 2024 extension of time and loss-and-expense package. Epidemic (cl 2.26.7) and change in law (cl 2.26.8) give time as of right but money only if the corresponding Relevant Matter option is selected in the Contract Particulars. A contractor that assumes the Relevant Events list and the Relevant Matters list are symmetrical has priced the wrong risk, and will discover it after the event rather than at tender.

NEC4's cl 60.1(19) is not a sweep-up. It is a three-part test: an event that stops the Contractor completing, which neither Party could prevent, and which an experienced contractor would have judged at the Contract Date to have such a small chance of occurring that it would have been unreasonable to allow for it. That is a materially higher bar than the sweep-ups in the other forms, and it is regularly cited as though it were the same thing.

Element 2, proving the event moved completion

Across the decisions gathered in this corpus, causation is where claims most often fail. The proof required is a before-and-after comparison of the critical path, isolated to the event in question, built on the project's own contemporaneous records, not a narrative, and not a cumulative analysis covering many instructions at once where the contract requires a case-by-case assessment.

Which analysis method is open to you is not a free choice. The method available is a function of the records you kept, and that set was fixed months before anyone knew there was a dispute, which is the argument developed in delay analysis methods and in records and evidence.

Three jurisdictions have independently moved in the same direction on this question, and the convergence is the most useful recent development in this area. In England, Thomas Barnes & Sons plc (in administration) v Blackburn with Darwen Borough Council [2022] EWHC 2598 (TCC) established the as-built critical path first and then found the effective cause, holding that experts are not confined to a single named method. In Australia, White Constructions Pty Ltd v PBS Holdings Pty Ltd [2019] NSWSC 1166 held that methodology must be driven by the factual evidence and that the SCL Protocol is not a rule of law. In Canada, Walsh Construction v Toronto Transit Commission, 2024 ONSC 2782 tolerated departures from AACE International RP 29R-03 where they were reasoned and grounded in contemporaneous records. In all three, the winning move was the record, not the method label.

Element 3: notice, and the three philosophies

Across the decisions gathered in this corpus, notice is the element that most often defeats an otherwise sound extension of time claim, and the standard forms do not merely differ in the length of the window. They embody three incompatible philosophies, and the deemed-acceptance mechanism (not the period) is what actually separates them.

Form-default clause machinery. The condition-precedent column is the corpus's reading. Bespoke amendment is normal on major projects, and the executed contract governs.

CCDC 2 – 2020 carries the earliest-running trigger in the table, because GC 6.5.4 runs its ten working days from the commencement of the delay rather than from awareness of it, so a contractor can be time-barred before it knew there was anything to notify. In Elite Construction Inc. v Canada (Attorney General), 2021 ONSC 562, a CAD 4.1 million delay and extras claim was dismissed on summary judgment for missing a ten-working-day notice.

The number that settles the argument about serving notices you think you do not need comes from the Gulf. In Panther Real Estate Development LLC v Modern Executive Systems Contracting LLC [2022] DIFC CA 016 (judgment 12 May 2023), the contractor lost its extension of time entitlement despite the employer having caused 304 of the 325 days of delay.

A statutory layer is now cutting across all of this in Australia, and it is new enough to have no interpretive guidance at all. The detail is in notice and time bars.

Element 4: how many days, and what concurrency does to the answer

The extent question is the "if and to the extent" limb, and it is decided net rather than gross. Where the answer becomes genuinely unpredictable is when a contractor-risk delay was running over the same period as the qualifying event, because concurrency is not settled law in any jurisdiction surveyed here, and the same facts produce materially different answers depending on the governing law and the executed contract.

The comparison below takes one fact pattern. A four-week overrun in which an employer variation and a contractor labour shortage were each independently critical over the same four weeks, with no express concurrency clause, and runs it through nine regimes.

Illustrative: one fact pattern run through nine regimes, not a survey of outcomes.

The spread across a single fact pattern runs from four weeks of time to none, and from no liquidated damages to all of them. That is the whole argument against reading a general article about concurrency and applying it to your project: the answer is a conflict-of-laws question and a contract-drafting question before it is a delay-analysis question. Two Australian standard forms give opposite answers on identical facts. The full treatment, including the five competing definitions of concurrency itself, is in concurrent delay.

Where these claims actually die

Across the reported decisions gathered in this corpus, extension of time claims fail in a consistent order, and it is not the order most submissions are written to defend against. This ordering is inference from a collected set of decisions, not a statistical sample. Treat it as a working heuristic rather than a finding.

Three of the four most common failure points are decided by what the project did during the works. Only one of them is decided in the dispute.

Worked example, a variation that arrives four weeks late

The following is illustrative and deliberately simple. It is written against JCT Design and Build 2024 for concreteness. The shape of the reasoning transfers, the clause numbers and the deadlines do not.

Templates and worked examples

The templates below are illustrative starting points, not contract-specific documents. Every one of them has to be checked against the executed contract before use: the recipient, the delivery method, the window and the required content are all contractual, and a notice served in the wrong form to the right person is as ineffective as one served late.

The register is the one that matters most. Of the four elements, three are decided by what the project did while the works were going on. A register maintained weekly costs a few minutes and preserves the ability to run a discrete, event-by-event causal case. The alternative is reconstructing commencement dates from memory months later, which is the single most attacked point in any delay claim.

Where to go next

The material below is scoped rather than general. Concurrency, notice and the choice of analysis method are the three places where a general answer is actively misleading, because the answer changes with the governing law and the executed contract.

• Concurrent delay: five competing models, five different answers, and no settled law in any jurisdiction surveyed.
• Notice and time bars: the three philosophies, the deeming mechanisms, and the new Australian statutory power to void a time bar retrospectively.
• Delay analysis methods. The SCL and AACE taxonomies, why they do not map cleanly onto each other, and how the records constrain the choice.
• Records and evidence, which records support which method, and what tribunals actually punish.
• Prolongation and delay costs. The money gateway, the period the effect was felt, and the no-damage-for-delay wall.
• Variations, the scope-and-price instrument. Where a change also moves the completion date, both run, on separate deadlines.

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 7, 2026 · Report a correction