Why Extension of Time Claims Fail, and How to Protect Entitlement
An extension of time claim is usually won or lost long before the merits of the delay are argued. In practice, entitlement is forfeited on two things the contractor controls: a programme that cannot demonstrate the delay affected completion, and a notice that arrives too late or without the content the contract requires. Both are avoidable, and both are decided during delivery, not in the dispute.
The programme decides the claim before the law does
Three programme failures weaken more extension of time claims than any point of law.
First, the baseline was never accepted. If the programme the claim rests on was never agreed with the superintendent, the entitlement is arguable from the first line, and the assessor is free to substitute their own view of what should have happened.
Second, the logic cannot show the path that actually controlled completion. The critical path is not fixed; it shifts as the work progresses, so a defensible claim shows the event affecting the critical path that governed completion at the time, not a late activity on the final programme. Excessive constraints, missing or illogical links, unexplained lags and unmanaged negative float obscure the critical path. Negative float by itself does not defeat a claim, it may only signal an imposed or already-late plan, but left unexplained it makes it difficult to separate delay the contractor owns from delay caused by imposed constraints.
Third, there were no contemporaneous updates. A programme that recorded actual progress, logic changes and forecast completion as the works advanced is far stronger than one reconstructed after the dispute, once memory and motive have set in.
Because the controlling path moves, a single project can carry several successful extension of time claims, each on a different critical path, however it would need to have been the critical path at the time of the delay. An event that sat well off the critical path in month three can govern completion in month nine, and each claim is assessed on the programme as it stood at the time, not necessarily the baseline nor the final as-built programme. Contractors lose entitlement here by testing every event against a single path, usually the last, rather than the path that controlled completion when the event occurred.
The baseline starts in the tender
The programme an extension of time claim rests on rarely first appears at contract award. The evidential story usually starts in the tender programme, and it carries whatever was built into it: a tender programme put together only to win the bid, on optimistic durations and a sequence nobody will work to, makes for a baseline an assessor can discredit. But tender status alone is not the baseline. After award the delivery plan has to be converted into an accepted, contract-compliant baseline, tested for logic and resources, reconciled to the contractual milestones, its assumptions documented and its acceptance obtained. That accepted baseline, and the updates that follow it, is what a later claim actually stands on. The work you can defend two years into a dispute begins at tender and is locked in at acceptance.
The notice can lose a claim the programme would have won
Entitlement can be extinguished on process alone, however strong the delay. Many contracts, including the unamended AS4000 and AS4902 forms, require a prompt notice of delay when the contractor becomes aware of a matter that will probably cause delay (cl 34.2), then a written extension of time claim within 28 days of when the contractor should reasonably have become aware of the cause, evidencing the facts of causation and the extent of the delay (cl 34.3). AS2124 uses a different mechanic, a written claim within 28 days after the delay occurs (cl 35.5). Special conditions frequently change the trigger, the deadline and the required content, so the governing clause, not the published form, is what matters.
Australian courts enforce clearly drafted notice conditions according to their terms. In CMA Assets Pty Ltd v John Holland [No 6] [2015] WASC 217 the Supreme Court of Western Australia upheld a notice condition that operated as a precondition to entitlement, a reminder that a principal's awareness of a delay does not cure a failure to give the notice the contract requires. And in Rimfire Energy Pty Ltd v BSF Co Pty Ltd (No 2) [2025] FCA 384 the Federal Court rejected extension of time claims because the notices did not meet the contract's substantive requirements, including showing that the delay was not caused by the owners or their EPC contractor. Timely notice was not enough.
Western Australia and Victoria now provide limited statutory relief from certain notice-based time bars. Under section 16 of the Building and Construction Industry (Security of Payment) Act 2021 (WA) and section 13A of the Building and Construction Industry Security of Payment Act 2002 (Vic), a decision-maker may declare a notice-based time bar unfair for a particular entitlement where compliance was not reasonably possible or would have been unreasonably onerous. These are not a general excuse for a late notice: the party alleging unfairness must prove it, the relief applies only to the entitlement in dispute, and for an extension of time the provisions reach only an EOT that affects a payment entitlement, with Victoria also covering release of performance security. Disciplined notice under the contract remains essential.
The programme is what lets you notify in time
Notice and programme are not separate disciplines. A competent notice of delay is drawn from the current programme: it identifies the activities the event is likely to affect, records the mitigation already underway, and gives an indicative view of the effect on the critical path and completion. It references the nearest accepted or updated programme rather than attaching one of its own, and it does not wait for a completed analysis before it goes in. The contractor who keeps the programme current is the contractor who can notify promptly and accurately, then substantiate and quantify the claim in the form and time the contract requires.
What protects entitlement
Winning the extension of time ground is a delivery discipline, not a dispute exercise. Get the baseline accepted. Keep the logic sound and the controlling path traceable through the updates. Update the programme contemporaneously. Notify promptly, drawn from the programme, and substantiate to the contract's requirements. And apply forensic thinking during delivery, not only after a claim arises, so embedded delay is surfaced while there is still time to act on it.
EOT entitlement control checklist
The controls that protect entitlement are simple to name and easy to let slip:
Identify the governing EOT clause, its amendments, deadlines, notice recipients and required content at project start.
Establish and preserve an accepted baseline, with its assumptions, calendars, logic and milestone links.
Keep a live delay-and-notice register: event date, awareness date, contractual deadline, owner and status.
Issue notices promptly, drawn from the current programme, without waiting for a completed analysis.
Update the programme on actual progress, with a written narrative for logic changes and revised forecasts.
Tie notices, instructions, correspondence, site records and programme updates to each delay event.
Protect the entitlement before you need it
Extension of time is won in the programme and the notice, during delivery, not reconstructed after the dispute. If you need your baseline, your updates and your notice process to hold when the claim is tested, that is the work we do, established during delivery, when entitlement can still be protected.
Common questions on extension of time
Why do extension of time claims fail?
More often on the programme and the process than on the merits. A baseline the superintendent never accepted, a controlling path that cannot be traced to the current events, or a notice that missed its window or lacked the required content will each sink an otherwise sound claim. The underlying delay can be real and the entitlement still lost.
What is the difference between a notice of delay and an extension of time claim?
They are two steps. The notice of delay flags the event when it arises, drawn from the current programme, so the superintendent can respond while the delay is live. The extension of time claim is the formal request to move the completion date, made within the contractual window and supported by programme evidence and causation. Some contracts combine them; many impose separate triggers, deadlines and content, so the particular clause governs.
Does the tender programme affect an extension of time claim?
Yes, more than most contractors expect. The baseline a claim relies on usually begins in the tender programme, so a programme built only to win the bid, with durations and a sequence that do not reflect how the work will run, produces a baseline an assessor can discredit. Converted after award into an accepted baseline, it becomes the foundation the later claim stands on.
Can a valid delay still lose its extension of time entitlement?
Yes. Australian courts enforce clearly drafted notice conditions. In CMA Assets Pty Ltd v John Holland [No 6] [2015] WASC 217 a time bar was upheld even though the principal knew of the delays, because the notice condition was a clear precondition to entitlement, and in Rimfire Energy Pty Ltd v BSF Co Pty Ltd (No 2) [2025] FCA 384 the claims failed because the notices did not meet the contract's substantive requirements. A real delay, notified late or without the required content, can still lose.
Does an extension of time claim need a critical path analysis?
Usually it needs a credible demonstration of how the event affected contractual completion, and on a complex project, particularly with concurrency, resequencing or existing delay, a critical-path or time-impact analysis is the clearest way to do it. The required method depends on the contract, the records and the event. A simple event may be established from other contemporaneous evidence; a complex claim will generally need the programme analysis.
Can a project have more than one extension of time?
Yes. Because the controlling path shifts over the life of a project, different delay events can drive completion at different times, each supporting its own extension of time. Each is assessed on the programme as it stood when the event occurred, not on the final programme, which is why a project can carry several valid claims on different critical paths.
When should you engage a delay consultant on an extension of time?
During delivery, not after the dispute. Getting the tender programme right, the baseline accepted, keeping the programme sound and updated, and notifying with the right content at the right time is what protects entitlement. Brought in early, a consultant surfaces embedded delay while there is still time to act; brought in after, they are reconstructing a claim from records that may not support it.
