Delay and Disruption Claims in NSW Construction: Extension of Time Claims and the Prevention Principle
Last reviewed: 30 September 2026.
Jurisdiction: New South Wales, Australia.
Currency note: Two NSW Acts that received assent on 14 August 2026 are relevant to this guide, but neither has yet changed the rules it applies. The detail is in the currency notes panel at the end of this guide.
Key takeaways
An extension of time buys time, not money. An extension of time (EOT) claim in a NSW construction contract protects the contractor against liquidated damages (LDs). It does not pay the contractor anything. Delay costs need their own contractual entitlement (a delay-costs clause or a variation) or a damages claim for breach.
The notice window usually decides the file. Under Turner Corporation Pty Ltd (Receiver & Manager Appointed) v Austotel Pty Ltd (1994) 13 BCL 378, a contractor that had a contractual route to an EOT and did not use it cannot fall back on the prevention principle. The notice period runs from the delay event, not from the day the LDs arrive.
The reserve power cuts both ways. Peninsula Balmain Pty Ltd v Abigroup Contractors Pty Ltd [2002] NSWCA 211; (2002) 18 BCL 322 (Hodgson JA; Mason P and Stein JA agreeing) and Probuild Constructions (Aust) Pty Ltd v DDI Group Pty Ltd [2017] NSWCA 151 generally require a superintendent or head contractor holding a unilateral power to use it for principal-caused delay. But "absolute discretion, no obligation to consider" drafting excluded that duty in Growthbuilt Pty Ltd v Modern Touch Marble & Granite Pty Ltd [2021] NSWSC 290.
Delay claims are often lost on process rather than merits. The usual causes are a late notice, no critical-path evidence, a global claim with no link between cost and cause, or acceleration on a verbal instruction. The record made on site in the week of the event is the evidence that decides the claim. The ten most common ways claims are lost are collected in the failure-mode library near the end of this guide. If you are short of time, read that first.
Table of Contents
Which situation are you in?
The same delay reaches you from one of several positions, and each asks a different first question. Find yours, go to the section listed, then read the matching scenario near the end of this guide.
You are… | Your first question | Start at | Matching scenario |
A contractor seeking time | Is there a qualifying cause, and was the notice given in time? | The sections on the contractual entitlement and on notices and time bars | Scenario 1 |
A principal or superintendent assessing a claim | Must I extend time, even without a compliant claim? | The sections on superintendent duties and on proving delay | Scenario 1 |
A contractor seeking money for delay | Where does the entitlement to delay costs come from? | The section on money for time | Scenario 3 |
A subcontractor or head contractor in the chain | Does the head-contract time regime flow down, and on what windows? | The section on delay down the chain | Scenario 2 |
A contractor who has already missed a notice window | Is there still a route to time, or a reason the time bar has not operated? | The sections on waiver and estoppel and on superintendent duties, then the steps for a missed window | Scenario 1 |
A residential builder or owner | How does the contract's EOT regime sit with the statutory timing warranty? | The section on residential building work | Scenario 4 |
Introduction
A principal who causes delay on a NSW job may still be entitled to deduct liquidated damages for that period if the contractor did not use its notice, its program and the contract's reserve power in the right order.
Take an AS 4000 warehouse. The principal's design information arrives late, and the contractor's crew stands down while it waits. Everyone on site knows why the job is behind. The contractor's contracts administrator means to "put the EOT in at the end". The contractual notice window closes. The superintendent declines to extend time, and the principal starts deducting liquidated damages. The contractor's answer is the prevention principle. The principal's answer is Turner v Austotel. This is the ordinary shape of an extension of time claim in NSW construction, and it is decided by process far more often than by who caused the delay.
The exposure reaches the whole industry. Head contractors carry it upward to developers and government principals, and pass it downward to trades. Superintendents carry it in a dual role that the courts police. Site supervisors create, or fail to create, the diary and program record that later becomes the only evidence. On many commercial jobs the accumulated liquidated damages are among the largest numbers in dispute, and the question underneath them is time.
The area is harder than it looks because three layers run on the same days. The contract sets qualifying causes, notice windows and a reserve power. The common law adds the prevention principle and time at large, and NSW courts have spent three decades working out how far a contract can shape or exclude them. Statute runs its own clocks alongside. The Building and Construction Industry Security of Payment Act 1999 (NSW) ("SOP Act") sets the payment-claim period in section 13(4), the due date in section 11, the payment schedule deadline in section 14(4) and the statutory-suspension requirements in section 27. The Home Building Act 1989 (NSW) ("HBA") adds its timing warranty, and limitation periods run in the background. None of these waits for an EOT assessment.
This guide works through the file in the order it arises. It covers what delay and disruption claims are, the NSW prevention line, the contractual entitlement, notices and time bars, how the superintendent assesses, how delay is proved, how money for time is recovered, delay down the subcontract chain, and where these claims are decided. It closes with drafting checklists, four NSW scenarios and a failure-mode library. As at 30 September 2026, two currency points apply, both set out in the currency notes panel at the end of this guide. In short, the Building (Approvals and Practitioners) Act 2026 (NSW) ("BAP Act") has received assent but section 202 has not commenced, and the in-force SOP Act still uses “business days”. Before counting a statutory deadline, check whether the enacted label change has commenced.
What delay and disruption claims are in a NSW construction contract
"Delay claim" is used loosely on site for four different claims, and each is won or lost on different evidence. This section separates them and routes the principal's side of the same delay to its own guide.
Delay, disruption, prolongation and acceleration: four different claims
Four claims come out of a late job, and conceding the wrong one is how contractors lose money they were owed.
Delay is late completion. The work reaches practical completion after the date for practical completion, and the question is whether that date should move. The contractual tool is the EOT. Its main legal function is to protect the contractor from liquidated damages and to keep the principal's LD regime alive by separating out delay the principal caused.
Disruption is lost productivity. The contractor works less efficiently because of out-of-sequence instructions, stacked trades, restricted access or piecemeal design release. Disruption may push completion out, or it may not. A contractor can be disrupted and still finish on time by spending more. That is why disruption is a money claim, not a time claim, and why it is proved by productivity evidence, not by a program.
Prolongation is the time-related cost of being on site longer: site overheads, supervision, plant, site sheds and preliminaries that run by the week. It usually follows an EOT but is not created by one.
Acceleration is the cost of recovering time. That cost may be incurred because the principal directed it, because the principal wrongly refused a valid EOT and left the contractor facing LDs, or because the contractor chose to catch up on its own account.
Each claim asks the same three questions: is there an entitlement to time, is there an entitlement to money, and who caused it? The answers do not travel together. An EOT for inclement weather above the allowance usually carries time and no money. A principal-caused delay can carry both. A disruption claim can carry money and no time. Site shorthand, and the habit of bundling delay and variation claims together in correspondence, hides these differences. The rest of this guide keeps them apart.
The single most expensive assumption in this area is that an EOT is an entitlement to money. It is not. Whether delay costs follow depends on a separate clause, discussed in the section on money for time.
Where liquidated damages in New South Wales construction fit
The contractor's EOT and the principal's liquidated damages are two sides of the same delay, but they are covered in separate guides for a reason.
Liquidated damages are the principal's pre-agreed remedy for late completion, running from the date for practical completion as adjusted by any EOT. Every day of extension granted is a day of LDs lost. That is why principals resist EOTs, and why the prevention principle, discussed next, exists. How the LD rate is set, whether it is a penalty under Paciocco, whether a $1 or nil rate leaves general damages open, and how LDs are levied through set-off and security are all covered in our guide to liquidated damages in NSW construction contracts.
This guide takes the other side. It asks when the contractor is entitled to more time, what happens when the machinery for giving time fails, and when a contractor can be released from a completion date altogether. Our liquidated damages guide has its own short treatment of prevention, written from the levy side. The treatment below is the canonical one and is written for the party who needs the time.
The prevention principle in NSW: rationale, reach and limits
This is where most delay analysis goes wrong. Contractors treat the prevention principle as a general fairness rule that rescues any principal-caused delay, and the NSW cases say something narrower and more useful. The four subsections below trace what "prevention" means, when it fails, when it can be contracted out, and what time at large actually delivers.
From the prevention principle to Spiers Earthworks: what "prevention" means
The doctrine is older than the standard forms, and the order of development explains its current shape.
If a contract has no mechanism to extend time for the principal's own delay, the principal cannot hold the contractor to the original date and so cannot recover liquidated damages. With no date to measure against, time is "at large". That is why every modern standard form includes an EOT clause for principal-caused delay: the clause exists partly to protect the principal's LD regime from prevention.
The Western Australian Court of Appeal gave the principle its modern Australian framing in Spiers Earthworks Pty Ltd v Landtec Projects Corporation Pty Ltd (No 2) [2012] WASCA 53. This is also persuasive in NSW. A party cannot insist on performance of an obligation that it has itself caused the other party not to perform. McLure P observed that the principle may be a manifestation of the duty to cooperate implied by law into contracts.
That observation matters in NSW because the Court of Appeal adopted it. In Probuild Constructions (Aust) Pty Ltd v DDI Group Pty Ltd [2017] NSWCA 151, McColl JA (Beazley ACJ and Macfarlan JA agreeing) explained the principle by reference to McLure P's reasoning. Prevention is a rule of construction and cooperation, not a free-standing equitable discretion to excuse late contractors.
In NSW, Turner Corp Ltd v Co-ordinated Industries Pty Ltd (1994) 11 BCL 202 gives three considerations that keep the principle in proportion:
If the EOT clause covers delay caused by the principal's breach or act, time is not set at large merely because the principal delayed. The contract has already provided for it.
Otherwise, the contractor must show actual delay to completion caused by the principal's conduct. Conduct that could have delayed the works, but did not, is not prevention.
The court looks at the overall effect. A small principal delay does not wipe out a large period of the contractor's own delay.
Taken together, prevention protects a contractor from being held to a date the principal made impossible. It does not reward a contractor that had a contractual route to more time and did not use it. The next subsection turns on that distinction.
Turner v Austotel: why a contractor who fails to claim is not "prevented"
The practical consequence of the NSW line is blunt. The notice you chose not to give is rarely rescued later.
In Turner Corporation Pty Ltd (Receiver & Manager Appointed) v Austotel Pty Ltd (1994) 13 BCL 378, Cole J said that where the contract provides a mechanism for extending time in respect of the relevant principal-caused delay, a contractor cannot rely on the prevention principle where it failed to exercise a contractual right that would have negated the effect of that delay. The builder argued that late instructions regarding a gas detector prevented completion, but it had claimed and obtained a seven-day EOT arising from that same event. Having received the contractual adjustment to the date for practical completion, it could not also rely on prevention to place time at large. The contract gave the builder a way to have the date moved. Cole J went further: a builder that has a right to claim an extension and fails to do so cannot claim that the principal's act of prevention excused it. That statement is generally treated as obiter, but NSW courts and commentators consistently apply it. On that reasoning, it is the contractor's own failure to use the contractual route, not the principal's conduct, that leaves it bound to the date for practical completion. The principal is not taking advantage of its own wrong. It is holding the contractor to machinery the contractor agreed to.
The contrasting approach is Gaymark Investments Pty Ltd v Walter Construction Group Ltd [1999] NTSC 143; (1999) 16 BCL 449, a Northern Territory decision arising from an application for leave to appeal from an arbitral award. There, the contractor had not complied with the contractual notice requirements. However, the contract had also been amended to remove the superintendent's discretionary reserve power to grant an extension of time despite non-compliance. Bailey J upheld the arbitrator's conclusion that, in those circumstances, there was no contractual mechanism capable of extending time for principal-caused delay and the prevention principle defeated the principal's liquidated damages claim. Gaymark has been widely criticised in subsequent commentary, and NSW decisions have generally preferred the Turner v Austotel approach. It is persuasive authority from another jurisdiction and should not be cited to a NSW court as though it stated local law.
Two qualifications keep Turner v Austotel from becoming absolute. First, it assumes the contractor could have claimed. If the EOT clause does not cover the relevant principal act, the contractor had no route and time may be put at large (see the section on time at large, below). Second, the NSW reserve-power cases (see the section on superintendent duties) may require the superintendent or head contractor to extend time for principal-caused delay even without a compliant claim. That is a contractual route to time, not a prevention defence, and it depends on the drafting.
Warning: Prevention rarely rescues a notice you chose not to give. If your contract gives you an EOT route for the principal's delay and you let the window close, assume in NSW that the prevention principle will not save you. Your remaining arguments are waiver or estoppel (see the section on waiver and estoppel) and the reserve power (see the section on superintendent duties), and both depend on facts you will have to prove.
If you have already missed a window, start with the steps under "If you have already missed the window", later in this guide. Then send Merlo Law the contract, the delay register and the correspondence around the event, and we can assess whether a reserve-power request or a waiver or estoppel argument is still open.
Contracting out: Probuild, Growthbuilt and "absolute discretion"
On a typical NSW standard form, prevention is preserved through the reserve power. On a heavily amended subcontract, it can be excluded altogether. The words decide which.
Probuild confirms that prevention can be modified or excluded by contract. The principle is not a mandatory rule. It gives way to clear drafting, so whether it survives in your contract is a question of interpretation, and a risk that should be priced at tender.
Growthbuilt Pty Ltd v Modern Touch Marble & Granite Pty Ltd [2021] NSWSC 290 shows what clear drafting looks like. The subcontract gave the head contractor an "absolute discretion" to extend time. It also said expressly that the head contractor had no obligation to extend time or even to consider doing so. Henry J held that these words left no room for an implied obligation of reasonableness or good faith in exercising the power. The parties had contracted out of the duty recognised in Probuild by expressly providing that the head contractor had no obligation to exercise or even consider the power to extend time. The subcontractor had not claimed an EOT under the subcontract's EOT clause, so its prevention defence failed. The court also held that the LD rate was not a penalty.
Growthbuilt is a first-instance decision, and the drafting was unusually explicit. The safe reading is not that "absolute discretion" alone always excludes prevention. It is that absolute discretion combined with an express statement that there is no obligation to exercise or consider the power was enough on those facts.
Decision path: has the clause excluded or preserved prevention?
Step | Question | If yes | If no |
1 | Does the EOT clause cover the principal's (or head contractor's) acts, omissions and breaches, including through a catch-all? | Go to step 2 | The contractor had no route to time for that delay. Time may be put at large (see the section on time at large) |
2 | Did the contractor make a compliant EOT claim within the contractual notice period? | Assess the claim on its merits (see the sections on the contractual entitlement and on proving delay) | Go to step 3 |
3 | Is there a reserve (unilateral) power to extend time? | Go to step 4 | Turner v Austotel is likely to bind the contractor to the date, subject to waiver or estoppel |
4 | Is the power held by an independent certifier with an express duty to act honestly and fairly, or by a party? | Certifier: Peninsula Balmain reasoning. Party: Probuild reasoning (see the section on superintendent duties) | — |
5 | Does the clause say the power is at "absolute discretion" and that there is no obligation to exercise or consider it? | Growthbuilt: prevention is likely excluded | A duty to extend for principal-caused delay is likely implied |
Run the table on the executed contract, including every special condition. The words that decide step 5 are often in an annexure no one on site has read.
Time at large: what it gives the contractor and what it does not
Time at large gives the contractor two things and takes away one.
When prevention applies and the contract has no working mechanism to extend time for it, the completion date falls away. The contractor's obligation becomes to complete within a reasonable time, assessed in all the circumstances, including the principal's delay. First, the liquidated damages machinery falls away with the date, because there is no date to measure LDs from, so the contractor avoids the daily rate for the period it covers. Second, the contractor gains leverage in the final account.
What it takes away is certainty. It does not free the contractor from liability for delay. If the contractor then fails to complete within a reasonable time, the principal may still recover general damages for delay beyond that time, proved in the ordinary way. That can be a bigger number than the capped LD rate the contractor escaped. Time at large is a defence to a levy, not an amnesty.
Time at large is also sometimes pressed into service in termination of construction contract disputes, as a basis for arguing that a principal could not rely on the contractor's lateness to terminate. That is a separate and high-stakes decision, and so is suspending work in response to non-payment. Neither is treated here. If suspension or termination is on the table, start with our analysis of suspending or terminating unpaid NSW pipeline contracts and get advice before acting.
Key cases at a glance
Case | Citation | Court | Principle | Binding in NSW? |
Turner Corporation Pty Ltd (Receiver & Manager Appointed) v Austotel Pty Ltd | (1994) 13 BCL 378 | NSW Supreme Court (Cole J) | A contractor that could have claimed an EOT and didn't is not "prevented" | Binds courts below the Supreme Court; persuasive for other Supreme Court judges |
Turner Corp Ltd v Co-ordinated Industries Pty Ltd | (1994) 11 BCL 202 | NSW Supreme Court (Rolfe J) | Three considerations: EOT clause covering principal breach; actual delay; overall effect | Binds courts below the Supreme Court; persuasive for other Supreme Court judges |
Gaymark Investments Pty Ltd v Walter Construction Group Ltd | [1999] NTSC 143; (1999) 16 BCL 449 | NT Supreme Court (Bailey J) | Contractor missed notice and the amended contract contained no reserve power to extend time despite non-compliance; prevention defeated liquidated damages. Widely criticised in commentary | No; not followed in NSW |
Peninsula Balmain Pty Ltd v Abigroup Contractors Pty Ltd | [2002] NSWCA 211; (2002) 18 BCL 322 | NSW Court of Appeal | Reserve power exercisable for either party; superintendent required to consider the reserve power honestly and impartially; on the facts, that duty required an extension for principal-caused delay despite no compliant claim | Yes |
620 Collins Street Pty Ltd v Abigroup Contractors Pty Ltd (No 2) | [2006] VSC 491 | Victorian Supreme Court | Applied and followed Peninsula Balmain, holding that the superintendent's reserve power to extend time could be exercised for the contractor's benefit and was not confined to the principal's interests | No (persuasive) |
Spiers Earthworks Pty Ltd v Landtec Projects Corporation Pty Ltd (No 2) | [2012] WASCA 53 | WA Court of Appeal | Prevention formulation; implied duty to cooperate | No (persuasive; reasoning adopted in Probuild) |
Probuild Constructions (Aust) Pty Ltd v DDI Group Pty Ltd | [2017] NSWCA 151 | NSW Court of Appeal | Party holding a unilateral power to extend time must exercise it honestly and fairly for delay it caused, by the prevention rationale or implied good faith; the outcome turns on the contract, and prevention can be excluded by clear words | Yes |
Growthbuilt Pty Ltd v Modern Touch Marble & Granite Pty Ltd | [2021] NSWSC 290 | NSW Supreme Court (Henry J) | "Absolute discretion" plus "no obligation to extend or consider" excluded implied good faith; prevention defence failed | Binds courts below the Supreme Court; persuasive for other Supreme Court judges |
The extension of time claim in construction: the contractual entitlement
Who this is for: contracts administrators and directors preparing or assessing an EOT claim.
Three things make up the entitlement: a qualifying cause, a compliant claim, and proof of critical delay. Each depends on the standard form in use and how it has been amended. This section maps the first two against the NSW standard forms. Proof is covered in the section on proving delay.
An EOT claim has a familiar anatomy regardless of form. It identifies the delay event and the date it began. It identifies the qualifying cause it falls under. It shows that the event delayed the work on the critical path to practical completion, not just some work. It states the days claimed. It attaches the program or delay analysis that supports those days. Many forms add that the contractor must have taken reasonable steps to mitigate, and that the delay was not caused by the contractor's own default. A claim missing any element gives the assessor a reason to reject it, and on many forms a rejected claim cannot be resubmitted once the window has closed.
Qualifying causes of delay, including weather and neutral events
Most claims that fail on entitlement fail here: the contractor proves delay, then finds the cause is not on the list.
A qualifying cause is one the contract says entitles the contractor to more time. Typical lists include:
acts, omissions, defaults or breaches of the principal, the superintendent or the principal's other contractors
variations
latent conditions
industrial action not specific to the contractor
inclement weather above a stated allowance of days
force majeure or events outside both parties' control
a catch-all such as "any other act, default or omission of the principal"
Some causes are "neutral". They are neither party's fault, and the contract may give time without money (weather, force majeure). Others are principal-risk events that may carry both.
The catch-all matters more than it looks, for prevention reasons. If a principal's act falls outside every listed cause and there is no catch-all, the contractor has no contractual route to time for it. Time may be put at large. A well-drafted catch-all protects the principal's LD regime. A narrowed or deleted one exposes it. Principals who strike the catch-all to reduce EOT exposure can, without realising it, reopen the prevention argument they were trying to close.
Weather clauses need precise reading. The allowance may be stated in days, by month, by reference to Bureau of Meteorology records, or by a site-specific test of when work is "prevented". Contractors should record in the site diary each day lost, why it was lost and what work was affected. They should not rely on rainfall totals alone.
The EOT regime ends at practical completion. Delay after that date does not generate liquidated damages, because the obligation LDs secure has been performed. Obligations during the defects liability period are a separate regime: the contractor's duty to rectify defects runs on its own terms and is not an extension of the completion obligation. Practical completion ends the time dispute. It does not end the relationship.
Latent conditions in construction as a delay event
The notice given on the day a latent condition is discovered usually controls both the time claim and the cost claim.
Latent conditions are physical conditions on or near the site that differ materially from what a competent contractor could have anticipated at tender, such as rock, groundwater, contamination or buried services. Whether they are a qualifying cause of delay depends entirely on the risk allocation. Many standard forms treat them as a principal-risk event, subject to notice. Many amended and design and construct contracts shift the risk to the contractor through site-investigation warranties or reliance disclaimers. Contamination also carries a separate regulatory layer, including notification duties and clean-up exposure.
Where latent conditions are a qualifying cause, the contractor usually has two separate claims with two separate procedures. One is a cost claim, often valued as a variation. The other is a time claim through the EOT clause.
The notice for the cost claim is frequently required "promptly" or within the period required by the contract after discovery, before the condition is disturbed. The EOT notice may run on a different window. Satisfying one does not always satisfy the other. A single well-drafted notice that identifies the condition, the date of discovery, the likely effect on cost and on time, and the intention to claim both is the safer course.
The delay proof is also distinct. A contractor that meets rock may argue about excavation rates for months. The time question is narrower: did the condition delay work on the critical path, by how long, and what did the contractor do to mitigate? Photographs, geotechnical logs, plant records and a revised program issued at the time are the evidence. A retrospective delay analysis prepared for a dispute a year later is weaker.
Variations as delay events: linking the variation claim in construction to time
Too often a variation is valued, paid and closed while its time effect is never assessed. Months later, both parties argue about LDs over a period that includes the added work.
A variation that adds work, changes sequence or adds a design step can delay completion. Most standard forms list variations as a qualifying cause of delay, but the time entitlement usually has to be claimed through the EOT clause. It does not happen automatically because the variation is priced. A variation claim in construction that deals only with money leaves the time open, and an open time question favours whoever controls the reserve power.
The discipline is simple to state: every variation, whether directed or agreed, should record its time effect in writing, even if the answer is "nil". A contractor that prices a variation and says nothing about time invites the argument that the time consequence was absorbed. A principal that directs a variation after the date for practical completion has passed, without addressing time, invites the Probuild argument. In Probuild, variations directed late in the job were part of the factual background to the adjudicator's view that time should have been extended.
How variations are valued (agreed rates, schedule rates, reasonable rates) is a contract-level question and outside this guide's scope. The time point here is separate from the price.
AS 4000, AS 2124, AS 4902, GC21 and Transport for NSW forms on time
The forms share a structure but differ at the edges, and the edges are where time is won and lost. For the general risk allocation under each form, see our guide to construction contracts in NSW. The time-specific differences are the ones that matter here.
AS 2124 and AS 4000 are construct-only forms that give the superintendent a reserve power to extend time even without a claim. Peninsula Balmain concerned a modified AS 2124-1992 contract. The Court's reasoning concerned the reserve-power wording before it, and may be relevant to comparable reserve-power provisions in AS 4000 where the contractual wording is materially similar. Since that decision, principals commonly amend the reserve power, for example by stating that it is exercisable only for the principal's benefit, at the superintendent's absolute discretion, or with no obligation to exercise it. Read the amended clause, not the published edition. Some editions also deal expressly with concurrent delay and with delay damages for defined categories of EOT, subject to annexure entries. Check how the edition and annexure in use deal with both. Clause numbers are deliberately omitted here because amendments and editions vary.
AS 4902 is the design and construct counterpart. On design and construct contracts, design development is usually the contractor's risk. The contractor's own design delays are not qualifying causes, and the latent-conditions allocation is often less favourable to the contractor.
GC21, the NSW Government's general conditions, is drafted around cooperation between the parties and a principal's authorised person in place of a traditional superintendent. Its collaborative contracting framing does not remove notice requirements. It raises the stakes of conduct that looks like acquiescence (see the section on waiver and estoppel).
Transport for NSW standard contracts for road and transport infrastructure typically contain detailed EOT and notice regimes, often with staged notices (an initial notice, then particulars) and their own treatment of weather and third-party interfaces. Transport for NSW uses its own suites of conditions as well as other government forms, so check the edition and amendments in the contract in use. Treat each staged notice as a separate condition until the contract tells you otherwise.
Form | Delivery | Time position described in this guide | What to check in the contract in use |
AS 2124 | Construct only | Superintendent reserve power to extend time without a claim. Peninsula Balmain concerned a modified AS 2124-1992 contract | Amendments confining the reserve power to the principal's benefit, making it absolutely discretionary, or removing any obligation to exercise it |
AS 4000 | Construct only | Superintendent reserve power; Peninsula Balmain reasoning may be relevant where the wording is materially similar | The same reserve-power amendments; how the edition and annexure deal with concurrent delay and delay damages |
AS 4902 | Design and construct | Design development usually the contractor's risk; the contractor's own design delays are not qualifying causes | The latent-conditions allocation, often less favourable to the contractor; the reserve-power wording in the edition in use |
GC21 | NSW Government works | Cooperative framing; a principal's authorised person in place of a traditional superintendent | Notice requirements still apply; conduct that looks like acquiescence carries higher stakes |
Transport for NSW | Road and transport infrastructure | Detailed EOT and notice regimes, often staged (initial notice, then particulars) | The edition and Transport for NSW amendments (often GC21-based); weather and third-party interface provisions; each staged notice as a separate condition |
Notices, time bars and conditions precedent
Who this is for: contracts administrators, and site supervisors who see the delay first.
Three rules govern notices in NSW: clear time bars are enforced; conduct can undo them; and statute reaches them only at the edges. Each subsection takes one rule.
Practice note: Diarise the notice window on the day of the event. The site supervisor who sees the late drawings, the rock or the stand-down should log the event that day and trigger the notice clock. The contracts administrator should diarise the contractual deadline for the initial notice and, separately, for the particulars. A notice given on day one can be refined later. A notice given after the window usually cannot be revived.
Model initial delay notice (adapt to your contract's content and form requirements)
To: [superintendent or head contractor's representative, as the contract requires]
Contract: [contract name; notice clause]
Subject: Notice of delay and intention to claim an extension of time: [event]
1. Event: On [date], [describe the event, for example: structural drawings for Level 2 had not been issued in response to RFI 047 dated …].
2. Cause relied on: [qualifying cause and clause, for example: act or omission of the principal under clause …].
3. Effect on the works: The event has delayed [activity], which is on the critical path in the program accepted on [date]. Our current estimate is [x] days' delay to practical completion. We will update this estimate as the effect becomes clear.
4. Cost: We expect to incur [delay costs or additional costs] and reserve our right to claim them under [clause] or otherwise.
5. Particulars: Further particulars will follow within [the period the contract requires].
We reserve all our rights, including our right to ask the superintendent to exercise its power to extend time.
Time bar clauses on variation and EOT claims: how NSW courts enforce them
The rule comes first because more contractor claims fail here than anywhere else: NSW enforces clearly drafted time bars.
A time bar clause makes compliance with a notice requirement a condition of the entitlement. It will usually say that the contractor is "not entitled" to an extension or a variation unless notice is given within the period required by the contract, or that the principal is released from liability for a late claim. NSW courts treat these provisions as the parties' bargain. The commercial logic is that the principal needs early warning so it can investigate, mitigate, re-sequence or change design while there is still time.
A clearly drafted time bar can defeat an EOT even where the principal caused the delay. That is the practical effect of Turner v Austotel. The contractor's failure to claim, not the principal's conduct, is what leaves it bound to the date. Do not expect the court to read a time bar down because the consequence is harsh or the delay was plainly the principal's.
Three things still need checking before you accept that a time bar has operated:
Is the requirement actually a condition precedent? Some clauses require notice but do not say what happens if it is late. That is a weaker bar.
What does the notice have to contain, and has something already sent satisfied it? A request for information (RFI), a meeting minute or an email saying the works are delayed by the principal's late drawings may amount to notice if the clause does not require a particular form.
Is there a reserve power that survives the bar (see the section on superintendent duties)?
The time bar is a first-order issue on every delay file. Check it before any other argument is run.
Waiver, estoppel and conduct that undoes a time bar
On paper the time bar looks absolute. On site, conduct often softens it.
A principal that consistently accepts late claims, assesses them on the merits without reserving its position, tells the contractor "don't worry about the paperwork, we'll sort time at the end", or runs the job through programs and minutes that record the principal's delay without insisting on notice may be found to have waived strict compliance. It may also be estopped from relying on the bar. Estoppel requires, in general terms, a representation or induced assumption, reliance on it by the contractor, and detriment if the principal were allowed to go back on it.
The Spiers litigation in Western Australia is a reminder that estoppel arguments about time can succeed on particular facts. Estoppel is real, but it is proved day by day, not as a general atmosphere of informality.
These arguments are harder than a compliant notice. The contractor carries the burden and needs documents, not recollections. The principal can protect itself with express non-waiver clauses and by reserving rights in writing whenever it considers a late claim. Contractors should treat waiver and estoppel as the fallback they are.
If you have already missed the window
Work through these steps in order, and do the first three this week.
Check that the time bar has actually operated. Is notice a condition precedent under this clause, or only a requirement? Has an RFI, a meeting minute or an email already said what the clause requires?
Ask the superintendent (or the head contractor, if it holds the power) in writing to exercise the reserve power for the identified delay, and to give reasons if it declines.
Give a notice and particulars now anyway. A late notice may not satisfy the bar, but it puts the material in front of whoever holds the reserve power and answers any argument that the delay is now too difficult to assess.
Collect the waiver and estoppel evidence: minutes, programs and emails that acknowledge the principal's delay, late claims assessed without a reservation of rights, and any "we'll sort time at the end" statements. Build it day by day, not as a general impression.
Keep the statutory clocks in view. A time dispute does not pause the payment claim, payment schedule or adjudication deadlines.
Onerous time bars and the unfair contract terms regime
Two statutory and doctrinal routes are sometimes suggested for attacking a short or onerous time bar. Each has a limited role, and one is often wrongly imported from Victoria.
The unfair contract terms regime. For a small trade business on a take-it-or-leave-it subcontract, this is the route worth checking first. If the subcontract is a standard form contract and the trade is a small business, an unfair time bar is void, and a party that proposes, applies or relies on it contravenes the Australian Consumer Law, being Schedule 2 to the Competition and Consumer Act 2010 (Cth) (ACL). Three practical points follow. First, the small-business test is fewer than 100 employees, or turnover of less than $10,000,000 for the last income year that ended at or before the contract was made. These thresholds, and the prohibition and penalties, apply to standard form contracts made or renewed on or after 9 November 2023, and to terms varied or added on or after that date. Older subcontracts that have not been renewed or varied are assessed under the earlier, narrower regime. Second, much of the burden sits with the party that drafted the term: a contract is presumed to be a standard form contract if a party alleges that it is, and a term is presumed not to be reasonably necessary to protect legitimate interests unless the advantaged party proves otherwise. Third, unfairness is still a contest. The term must meet the three-limb statutory test, and the head contractor will argue that early notice protects a legitimate interest. A fully negotiated head contract between sophisticated parties is unlikely to engage the regime at all.
The provisions are sections 23(1), 23(2A), 23(2C), 23(4), 23(6), 24(1), 24(4) and 27(1) of the ACL. Section 26 excludes certain terms from section 23. In New South Wales, sections 27, 28 and 32 of the Fair Trading Act 1987 (NSW) apply that text as the Australian Consumer Law (NSW), and section 30(4) includes the Tribunal as a court for Part 2-3 of the ACL. Check the current thresholds and exclusions against the ACL before relying on this.
Penalty doctrine. Commentators have asked whether a very short time bar that forfeits a substantial entitlement could be attacked as a penalty after Paciocco v Australia and New Zealand Banking Group Ltd [2016] HCA 28. No NSW authority has settled that question. Treat it as an open argument, not a rule.
Victoria is not NSW. Section 13A of the Building and Construction Industry Security of Payment Act 2002 (Vic), inserted by section 13 of the Building Legislation Amendment (Fairer Payments on Jobsites and Other Matters) Act 2025 (Vic) (No. 43/2025), permits a notice-based time bar provision to be declared unfair. The definition includes a provision that makes entitlement to an extension of time contingent on notice. It does not apply in NSW. The NSW SOP Act contains no equivalent, and section 22(2) does not permit a NSW adjudicator to disregard a contractual time bar on Victorian principles.
Superintendent duties under a construction contract: assessing EOTs
Who this is for: superintendents, contracts administrators on the principal's side, and directors who appoint them.
Under the NSW reserve-power cases, the superintendent's decision not to act can matter as much as any decision it makes. This section separates the three positions the cases recognise.
Practice note: If you are the contractor, ask the superintendent in writing whether it is exercising or declining the reserve power for an identified delay, and why. If you are the superintendent, answer in writing with reasons. Silence helps neither party. It leaves the contractor without a decision to dispute and leaves the superintendent's reasoning open to reconstruction in hindsight.
The superintendent's impartiality obligation and the dual role
On commercial forms the superintendent wears two hats, and the courts expect it to know which one it has on.
As agent, the superintendent acts for the principal: issuing directions, instructing variations and communicating the principal's decisions. As certifier or assessor, it decides matters between the parties: valuing payment claims, assessing EOT claims, certifying practical completion. In that second role the standard forms, and the cases, require it to act independently of the principal's commercial interest. Many forms make this express by requiring the superintendent to act honestly and fairly, within the time prescribed, and reasonably. Where the form is silent, the certifying function still carries a duty to act honestly and independently.
In practice, the superintendent impartiality obligation means an EOT assessment must be based on the contract and the evidence. It must not be influenced by what the principal would prefer, even though the superintendent is often the principal's employee or consultant. A superintendent who takes instructions from the principal on EOT assessments, or declines to assess because the principal has told it to "hold the line", exposes the principal to claims that the certification was invalid. The principal may be liable if it interferes with the certifier.
The unilateral power to extend time after Peninsula Balmain
Sequencing matters here: first the contractor misses the notice, then the principal-caused delay is established, and only then does the reserve power become the contractor's best argument.
In Peninsula Balmain Pty Ltd v Abigroup Contractors Pty Ltd [2002] NSWCA 211, the contractor had not made compliant EOT claims for delay caused by the principal. The contract gave the superintendent a unilateral power to extend time, and required the superintendent to act honestly and fairly. The Court of Appeal held that the power could be exercised for the benefit of either party, not only the principal, even though it exists largely to preserve the principal's LD regime against prevention. Because the contract required the superintendent to act honestly and fairly, and because the Court held that the reserve power had to be exercised honestly and impartially, the superintendent was obliged on the facts to extend time for the principal-caused delay despite the absence of a compliant claim. The Victorian Supreme Court followed and applied that reasoning in 620 Collins Street Pty Ltd v Abigroup Contractors Pty Ltd (No 2) [2006] VSC 491, holding that the superintendent's reserve power could be exercised for the contractor's benefit and was not confined to the principal's interests. The decision is persuasive, rather than binding, in NSW.
The effect is to soften Turner v Austotel without overruling it. The contractor who failed to claim is still not "prevented". But where a superintendent holds a reserve power and is required to exercise it honestly and impartially, the contractor may still obtain an extension of time if a fair consideration of the circumstances requires one. The result remains fact-dependent. A superintendent acting honestly and fairly can take into account that a late claim has made the delay harder to assess, so the contractor should not treat the reserve power as a substitute for a timely notice.
Principals responded predictably. Many NSW contracts now amend the reserve power to say it is exercisable only for the principal's benefit, at the superintendent's absolute discretion, and without any obligation to exercise it. Whether those amendments achieve their object depends on the words and on Growthbuilt (see the section on contracting out, above). Treat each amended clause as its own question.
The EOT determination often surfaces in a progress certificate dispute. A superintendent's refusal to extend time feeds straight into a certificate that allows the principal to deduct LDs. The contractor's challenge to the certificate is, underneath, a challenge to the time decision. Framing it that way from the start keeps the dispute on the right issue.
When the principal holds the power itself: Probuild and implied good faith
The error to avoid is assuming that, without an independent certifier, there is no duty at all. The Court of Appeal held otherwise.
In Probuild Constructions (Aust) Pty Ltd v DDI Group Pty Ltd [2017] NSWCA 151, DDI was a plasterboard subcontractor on a hotel redevelopment. It finished well after the date for completion, having made no EOT claims and not complied with the variation notice procedures. Probuild set off liquidated damages in response to DDI's payment claim. The subcontract had no superintendent. Probuild held the unilateral power to extend time itself, and there was apparently no express obligation to act honestly and fairly.
The matter reached the Court of Appeal as a challenge to an adjudication determination. The adjudicator had decided it was unreasonable for Probuild not to have extended time, particularly where variations were directed after the date for completion had passed. McColl JA (Beazley ACJ and Macfarlan JA agreeing) held that Probuild was obliged to exercise the power to extend time in clause 41.9 honestly and fairly, "having regard to the underlying rationale of the prevention principle to which I have earlier referred or, if necessary, because there is an implied duty of good faith in exercising the discretion cl 41.9 conferred" (at [128]). That is a duty to consider and decide the question properly, not an automatic entitlement to time. The Court stressed that whether there had been acts of prevention, and whether Probuild was entitled to LDs, turned on the terms of the subcontract in the events that had happened (at [129]).
Two points remain unsettled. First, the Court did not spell out the content of the implied good-faith duty. It is open whether a party holding the power must consider delay on its own knowledge, give reasons, or excuse other preconditions. Second, Growthbuilt shows that the duty can be excluded by express words. Until an appellate court fills in the content of the duty, the prudent course for a head contractor holding the power is a documented, fair assessment of the delay it caused. The prudent course for a subcontractor is not to rely on the duty at all.
Proving delay: critical path, concurrency and the record
Who this is for: contracts administrators preparing or testing a claim, and site supervisors who produce the evidence.
Three things carry the proof: the program, the contract's rule for concurrency, and the contemporaneous record. A claim with all three is hard to reject. A claim missing one is usually rejected.
Critical path, float and delay analysis methods
These are the tools, mapped to their function. The contract decides which ones are compulsory.
The critical path is the sequence of activities whose delay delays practical completion. An event that delays non-critical work does not, on its own, entitle the contractor to an EOT, because it does not delay completion. The claim must show that the event hit the critical path, or created a new one, and by how much.
Float is the slack in non-critical activities. Who owns it depends on the contract. Some contracts say float belongs to the contractor, so a principal delay that consumes float is still compensable in time. Others say float is shared or belongs to the project, so principal delays absorbed by float give no EOT. Many say nothing. Read the program clause before assuming either way.
Methods. Delay analysis methods range from simple comparisons of the as-planned program with the as-built record, through time-impact analysis (inserting the delay event into the program current at the time and measuring the effect), to windows analyses that divide the job into periods and assess critical delay in each. They differ in cost, in the records they need, and in how well they handle multiple overlapping events. The contract may prescribe a method or a program standard. If it does, use it. If it doesn't, choose a method your records can support. An elaborate analysis built on programs that were never updated during the job invites attack on its foundations.
Method | How it works | Records it needs | Best suited to | Usual line of attack |
As-planned v as-built | Compares the baseline program with what actually happened and attributes the difference to delay events | Approved baseline program; reliable as-built dates | Simpler jobs with few, well-separated events | Assumes the baseline was achievable; struggles to separate overlapping causes |
Time impact analysis | Inserts a modelled delay event into the program current at the time and measures the shift in completion | Accepted program updates at each event date; clear event dates | Prospective EOT claims made during the job | Measures theoretical rather than actual effect; only as good as each update |
Windows analysis | Divides the job into periods and identifies the critical path and critical delay in each | Regular program updates and as-built records for every window | Long jobs with many overlapping events, including concurrency | Choice of window boundaries; a gap in updates undermines a whole window |
The UK Society of Construction Law's Delay and Disruption Protocol (2nd edition, February 2017) is widely referred to in Australian practice as a reference point for choosing and applying a method. It is guidance only and binds no one unless the contract adopts it.
The approved baseline program and each accepted update are the documents that give any method its credibility. Without them, the analysis is an opinion. If the matter reaches a hearing, the analysis will usually be led as expert evidence, and in a construction dispute the opposing expert will test it against those documents before anything else.
Concurrent delay: the contract decides it
On concurrency the contract does most of the work, and the common law fills only the gaps the drafter left.
Concurrent delay arises where two or more causes delay completion over the same period, and at least one is the principal's risk while another is the contractor's. The questions are whether the contractor gets time, money, both or neither.
Start with the contract. Some forms and many bespoke contracts include a concurrency clause. It may deny an EOT where a contractor-caused delay overlaps. It may grant time but not money. It may direct the assessor to apportion the delay by each cause's contribution. Each approach is enforceable if clearly drafted, and each produces a different answer from the same facts. Principals commonly amend concurrency clauses in their favour, so check the special conditions.
If the contract is silent, the NSW starting point is the overall-effect consideration from Turner Corp Ltd v Co-ordinated Industries Pty Ltd. A small principal delay does not wipe out the contractor's own substantial delay, and the analysis looks at the combined effect on completion rather than awarding the contractor the whole overlap automatically. How that consideration applies to evenly matched concurrent causes has not been settled by a single NSW appellate formula. Where the stakes justify it, treat a silent contract as a live argument and get delay-analysis evidence early.
The records that win or lose a delay claim
Everything in this part of the guide comes back to one point: the site record, not the claim document, decides the file.
The records that do the work are:
Site diaries, kept daily, recording who was on site, what work was done, what was stopped and why
Program updates issued at the contract's required intervals, with narrative explaining changes to the critical path
A delay register logging each event, its date, the cause relied on, the notice given and the claim status
RFIs, with their response dates, because late answers are often the principal's delay
Minutes that record, in the principal's or superintendent's own words, that a delay exists and what caused it
The worst records are the ones created after the dispute starts. Programs produced months later to support a claim, diaries written up in bulk, and registers reconstructed from email searches are all open to credibility attacks that contemporaneous records avoid.
Practice note: Keep one delay register that links each event to its RFI, its notice, the relevant program update and the claim. Give the site supervisor the job of opening the entry on the day of the event and the contracts administrator the job of closing it. A single register lets anyone reconstruct the file in an afternoon. Scattered emails take weeks and leave gaps.
If you are a small trade without a programmer or a contracts administrator, you do not need a delay expert to protect a claim. You need a short daily record, made on the day, and a notice sent in time.
A minimum diary entry covers:
the date, the weather, and who was on site, including your crew and any other trades in your area
what work you did, and what work you could not do
why you could not do it, in one line (for example, "Level 3 ceilings not closed by others; no access")
who you told, and how (text, email or site meeting)
photos taken, labelled with the date and location
An email to the head contractor that says, on the day, what was delayed, why, and that you intend to claim time may be enough to satisfy a notice clause that does not prescribe a form. Check your subcontract, and send the email anyway.
Money for time: delay costs, disruption and acceleration
Who this is for: directors and contracts administrators pricing and pursuing a contractor-side delay claim.
Contractors overclaim and principals underpay here for the same reason: both treat the EOT as though it settled the money. The four subsections below separate the source of the entitlement, the proof, the global claim trap, and acceleration.
Where the entitlement to delay costs comes from
Three sources can pay for time, and the EOT is not one of them.
A contractual delay-costs clause. Many standard forms give the contractor delay costs or delay damages for defined categories of EOT, usually principal-risk events, sometimes at a daily rate stated in the annexure and sometimes as reasonable costs incurred. The clause may exclude neutral events such as weather and industrial action. It may cap the recovery, or make a daily rate the exclusive measure. If the annexure says "nil", or the clause has been deleted, that is usually the end of the contractual route for those events.
A variation. Where delay flows from a directed variation, the time-related cost may be valued as part of the variation itself. The contractor then needs to make sure the variation valuation actually includes the time-related component, not just the direct cost of the added work.
Damages for breach. Where the principal's delay is a breach of contract (late access, late information, failure to cooperate), the contractor may claim damages at common law. Contractual exclusions, caps, exclusive-remedy provisions and time bars may cut this route down. Many contracts say the delay-costs clause is the only remedy for the listed events.
The order of analysis follows from this. First establish the EOT, because it proves the event and its critical effect. Then find the money clause that covers that event. Then prove the amount. A contractor that skips the second step and claims "prolongation" because an EOT was granted is often told, correctly, that the EOT was for a no-cost cause.
Worked example (illustrative figures only, not market benchmarks). The principal's design information arrives late and delays practical completion by 42 days. The LD rate is $5,000 a day. The contractor's time-related site costs (supervision, sheds, plant and similar preliminaries) run at $3,000 a day. The annexure provides delay costs of $2,500 a day for principal-caused EOTs.
Outcome | LDs deducted | Time-related costs recovered | Contractor's net exposure |
No compliant notice and no EOT | $210,000 | Nil | $336,000 ($210,000 LDs plus $126,000 unrecovered site costs) |
EOT granted, but for a no-cost cause (or delay costs stated as "nil") | Nil | Nil | $126,000 |
EOT granted, and the delay-costs clause applies | Nil | $105,000 | $21,000 |
The gap between the first and last rows is $315,000 on a single event. The notice decides the first $210,000 of it. The money clause decides the rest.
Prolongation and disruption: proving the number
Prolongation and disruption are proved differently, and running one as if it were the other is a common way to lose both.
Prolongation covers the time-related costs of the extended period: site supervision, site establishment, plant and equipment retained on site, insurance and bonds extended, and site-specific overheads. It is proved by showing what those resources actually cost during the extended period and that they were there because of the delay, not because the contractor was catching up on its own work. The better evidence is cost records for the specific delay period, not the average weekly preliminaries from the tender. Head-office overheads and lost profit on other work are harder claims, need evidence of actual loss, and are often excluded by the contract.
Disruption covers lost productivity. It is proved by comparing the productivity actually achieved in the disrupted period against a baseline: an undisrupted period on the same job, or a reliable benchmark. It needs labour records, quantities installed and a causal story linking the disruption to specific principal acts. Disruption may not delay completion at all, so an EOT is neither necessary nor sufficient.
Both claims fail when the contractor cannot separate its own inefficiencies from those caused by the principal. The records that make that separation possible are the ones described in the section on the records that win or lose a delay claim.
Global claims and why they are vulnerable
A total-cost comparison is not proof of causation.
A global (or "total cost") claim takes the contractor's actual cost, subtracts its tender cost, and attributes the whole difference to the principal's delay events, without linking each cost to each cause. It is attractive because it is cheap to prepare when records are poor. It is vulnerable for the same reason. If any part of the overrun is attributable to something the principal is not responsible for, such as under-pricing at tender, the contractor's own inefficiency, a subcontractor's failure or a non-compensable event, the claim has not proved how much the principal caused. The whole claim can fail rather than just the unproven part.
Courts have not rejected global claims outright, and a claim may survive where the contractor can show that the principal's events are the only realistic cause of the overrun and that it is not practicable to separate costs event by event. That is a heavy burden. The better practice is to allocate costs to causes wherever the records allow, and to confine any global element to the residue that genuinely cannot be separated. Two Victorian decisions are commonly cited on global claims and are persuasive in NSW: Nauru Phosphate Royalties Trust v Matthew Hall Mechanical & Electrical Engineers Pty Ltd [1994] 2 VR 386 and John Holland Construction & Engineering Pty Ltd v Kvaerner RJ Brown Pty Ltd (1996) 8 VR 681; (1997) 82 BLR 81.
Directed, constructive and voluntary acceleration
The three kinds of acceleration are sequenced by who decided to accelerate, and that decides who pays.
Directed acceleration is an instruction from the principal or superintendent to complete earlier than the contractor is entitled to, or to recover delay the principal caused. It is ordinarily a variation, valued under the contract's variation clause. The contractor's protection is to get the direction in writing, identify it as an acceleration direction, and state that it will be claimed as a variation.
Constructive acceleration is the harder claim. The contractor was entitled to an EOT, the EOT was wrongly refused or ignored, and the contractor accelerated to avoid LDs. The contractor then claims the cost of acceleration as if it had been directed. The argument has intuitive force, but whether and how it is recognised in NSW law is unsettled. It is heavily dependent on evidence: the contractor must show the EOT entitlement, the wrongful refusal, that it accelerated because of the refusal, and what the acceleration cost. It is a poor substitute for pursuing the EOT through the contract. The better course is to press the EOT through the dispute mechanism while accelerating only under express protest, with a written reservation of rights.
Voluntary acceleration is the contractor's own decision to recover its own delay, or to finish early for commercial reasons. It is at the contractor's cost.
Warning: Don't accelerate on a verbal instruction. A superintendent or site manager who says "get more crews on, we need this finished" has not, by saying it, issued a variation. Without a written direction, the contractor's acceleration can later look voluntary. Site supervisors should ask for the instruction in writing before mobilising extra resources and, if they don't get it, confirm it back in writing the same day.
Delay down the chain: head contractors and subcontractors
Who this is for: subcontractor coordinators, and directors on both sides of a subcontract.
On the head contract the principal carries the principal's delay. On the subcontract the head contractor is the "principal", and it may pass on less than its drafting suggests or more than is fair. Most subcontractor disputes over time in NSW construction turn on two issues, flow-down and pass-through, and this section covers both.
Back-to-back construction contracts: flowing the time regime down
The recurring practical problem is a subcontract whose notice windows are longer than the head contract's, so that the head contractor learns of the delay too late to claim it upstream.
A back-to-back construction contract aims to pass the head-contract time risk down to the subcontractor who causes, or suffers, the delay. For time, that means aligning three things. The qualifying causes in the subcontract should include the principal's delay events, so the subcontractor gets time when the head contractor does. The notice windows should be shorter than the head-contract windows by a workable margin, so that the head contractor can collect a subcontractor's notice and turn it into its own claim in time. The EOT decision under the subcontract should track the decision under the head contract, and the subcontract should say what happens if the head-contract assessment is delayed or disputed.
Mechanical copying does not achieve this. A flow-down clause that simply incorporates the head-contract clauses into the subcontract by reference will often give the subcontractor the same window as the head contractor, which leaves the head contractor no time to pass the claim up. Conversely, a subcontract window so short that no trade can realistically comply invites the unfair-terms scrutiny discussed in the section on onerous time bars when the subcontract is on standard form terms.
Practice note: Set subcontract notice windows inside the head-contract windows. Map each head-contract notice step to its subcontract equivalent, fix the subcontract step early enough to allow for collation and review, and diarise both. If you are the subcontractor, find out the head-contract window. Your practical deadline may be earlier than your subcontract suggests if you want the head contractor to carry your claim upstream.
Pass-through claims, principal-supplied items and nominated trades
A subcontractor's delay claim usually does not run directly against the principal.
A subcontractor delayed by the principal's conduct generally claims against the head contractor under the subcontract. The head contractor then passes that delay up as its own claim against the principal. Pass-through arrangements, where the subcontract ties the subcontractor's recovery to what the head contractor recovers upstream, need careful drafting. Their enforceability depends on the words and on the SOP Act. This is where a pay-when-paid clause in a New South Wales subcontract usually runs into trouble. Section 12(1) of the SOP Act provides that a pay-when-paid provision has no effect in relation to payment for construction work carried out or undertaken to be carried out, or related goods and services supplied or undertaken to be supplied. Section 12(2)(c) also catches a provision that makes the liability to pay, or the due date, contingent or dependent on the operation of another contract.
Causation governs every step. The head contractor must show that the principal's event caused the subcontractor's delay and its own delay to practical completion under the head contract. A delay that held up one trade but not the critical path of the whole project may give the subcontractor an EOT without giving the head contractor one.
Items the head contractor or principal supplies, such as materials, access, design information, preceding trades and nominated subcontractors, can each be the source of prevention within the subcontract. A head contractor whose other trades delay a subcontractor's access, and which then levies subcontract LDs, is in the Probuild position (see the section on Probuild and implied good faith) unless its drafting has taken it to the Growthbuilt position (see the section on contracting out).
Where several parties in the chain contributed to the same loss, proportionate liability under Part 4 of the Civil Liability Act 2002 (NSW) ("CLA") may arise, but only for an apportionable claim as defined in section 34(1), and not for a Part 2C HBA warranty claim brought by a person having the benefit of that warranty (section 34(3A) of the CLA).
Where delay claims are decided: security of payment, residential work and forum
Behind every delay file sit the statutory payment regime, the residential warranty regime, the contract's dispute clause and a set of running clocks. This section maps each to its function and points to the detailed guides.
Delay costs and EOTs in a NSW payment claim and schedule
Time disputes and statutory deadlines collide in the payment claim, and the deadlines usually win.
Whether delay costs can be included in a NSW payment claim depends on the construction contract's entitlement. The SOP Act gives a right to progress payments for construction work carried out and related goods and services supplied. Under section 9, the amount is calculated under the contract. If the contract makes no express provision, it is calculated on the value of the work or related goods and services under sections 9(b) and 10. In an adjudication, section 22(2) limits the matters the adjudicator may consider. NSW has never had a statutory "excluded amounts" regime of the kind that applied in Victoria until that regime was removed from 15 April 2026. A contractual delay-costs entitlement can be claimed through the SOP Act process, and an adjudicator may deal with it only by reference to the matters listed in section 22(2). The adjudicator's approach to damages claims that are not contractual entitlements is a matter for the specialist guides.
On the respondent's side, a principal that intends to deduct LDs while an EOT is under assessment faces a sequencing problem. It must decide the time question well enough to put a quantified deduction, and the reasons for withholding, in the payment schedule under sections 14(2) and 14(3) of the SOP Act. Those reasons cannot be added for the first time in an adjudication response: section 20(2B). The deduction also has to meet the due date under section 11, including sections 11(1A), 11(1B), 11(1C) and 11(8). That sequence is set out in our guidance on deducting liquidated damages while an EOT claim is pending.
Two clocks matter most on a delay file. Under section 14(4) of the SOP Act, a respondent that does not provide a payment schedule within the time required by the contract, or within 10 business days after the payment claim is served, whichever expires earlier, becomes liable to pay the claimed amount on the due date for the progress payment. A separate clock applies before that stage. Under section 13(4), a payment claim may be served only within the period fixed by the contract, or 12 months after the construction work was last carried out or the related goods and services were last supplied, whichever is the later. On residential work, section 8(2) removes the progress-payment entitlement if the contract does not comply with section 4 of the HBA, or the work is residential building work done in contravention of section 92 of the HBA. For orientation, the entitlement, valuation and due-date provisions are sections 8, 9, 10 and 11 of the SOP Act, and the claim and adjudication framework is in sections 13, 14, 15, 17, 20 and 22.
Currency note: the Fair Trading and Building Legislation Amendment Act 2026 (NSW) will change the label in section 14(4) of the SOP Act once the amendment is proclaimed. The in-force section 14(4) uses business days, and section 4(1) already excludes 27, 28, 29, 30 and 31 December. When this guide was last checked against the in-force text (29 September 2026), it had not changed.
For the regime end to end, see our guide to security of payment and adjudication in New South Wales. For the claim and schedule mechanics, see payment claims and payment schedules in NSW. For the determination stage, see adjudication in NSW. If a delay-cost item is in a live payment claim, or an adjudication application in New South Wales is being prepared or answered, get security of payment advice from Merlo Law before the next statutory deadline, not after it. Once a schedule deadline has passed, the options narrow sharply.
Warning: SOP deadlines don't wait for an EOT assessment. A superintendent's EOT assessment that is "still in progress" does not extend the payment schedule deadline, and payment schedule failure in New South Wales carries the same consequence whether or not a time dispute is running. A respondent that misses the window in s 14(4) of the SOP Act while an EOT is under assessment becomes liable under section 14(4) to pay the claimed amount on the due date. If it remains unpaid, section 15 applies.
Residential building work: the Home Building Act timing warranty
On commercial work the contract does most of the running. On residential work it does less than its drafting suggests.
Residential building work carries the statutory warranties implied by s 18B of the HBA. The one that matters for delay is s 18B(1)(d): a warranty that the work will be done with due diligence and within the time stipulated in the contract, or, if no time is stipulated, within a reasonable time. Two features set it apart from a contractual completion date. First, it cannot be contracted out of: section 18G makes void a provision of an agreement or other instrument that purports to restrict or remove the rights of a person in respect of a statutory warranty. Second, it runs on its own limitation clock. Section 18E(1)(b) sets the warranty period at 6 years for a breach resulting in a major defect (defined in section 18E(4)) and 2 years in any other case. For a timing claim, that ordinarily means the 2-year period, because a timing-warranty claim for rent is not, without more, a major-defect claim.
When that period starts depends on where the job ended up. Where the work is complete, section 18E(1)(c) of the HBA starts it on completion, determined under section 3B. For new buildings in strata schemes, completion is fixed under section 3C instead (section 3B(1A) and the note to section 3B). If the work is not complete, section 18E(1)(d) starts the period on termination, cessation of work, or the date of the contract, as applicable. Section 18E(1)(e) allows a further 6 months if the breach becomes apparent in the last 6 months, and section 18E(1A) can extend the 2-year period where a building bond has been lodged under Part 11 of the Strata Schemes Management Act 2015 (NSW).
For builders, the EOT clause in a residential contract works alongside the timing warranty, not in place of it. A builder with a valid EOT for owner variations has a strong answer to a timing warranty claim for that period. A builder relying on an agreement or other instrument to shut out the warranty altogether is on weaker ground because of section 18G of the HBA. The person enforcing the warranty also has duties under section 18BA, including mitigation and written notice of the breach within 6 months after it becomes apparent. Section 18B(2) implies the warranties in a contract between a principal contractor and a subcontractor for residential building work.
In practice, residential builders should run the contract's EOT process as strictly as they would on a commercial job. Owners are rarely familiar with notice clauses, so give each EOT notice in the form and to the address the contract requires, explain the cause in plain terms, and attach the variation or wet-weather record it relies on. Record the time effect on every variation document the owners sign. Where the owners claim rent or alternative accommodation for late completion, the dispute usually turns on two questions: which days of delay the builder can show were caused by owner variations, weather or other causes the contract allows for, and whether the owners' claimed costs were actually incurred and reasonably mitigated, as section 18BA of the HBA requires of them.
Residential building disputes are commonly decided in the NSW Civil and Administrative Tribunal (NCAT), and NCAT jurisdiction in a building dispute has both a monetary limit and time limits. Under section 48K(1) of the HBA, the Tribunal’s jurisdiction is limited to a building claim not exceeding $500,000, or another figure prescribed by the regulations. Under section 48K(7), it has no jurisdiction over a Part 2C statutory-warranty claim lodged after the end of the section 18E period. Sections 48K(3), 48K(4) and 48K(8) impose separate 3-year limits on other building claims. “Building claim” is defined in section 48A. The forum and the regulator are covered in our guide to NCAT and the Building Commission in NSW. The NSW Civil and Administrative Tribunal publishes its own procedural guidance. If a residential delay claim is heading to the Tribunal, advice on the NCAT building dispute pathway should come before the application is filed.
Currency note: sections 18B(1)(d), 18E and 18G of the HBA remain in force. Section 202 of the BAP Act does not repeal them.
When a delay claim becomes a construction contract dispute in New South Wales
The sequence usually runs from notice, to rejection, to the contract's dispute clause, and only then to a forum.
Most delay claims start inside the contract: a notice, a claim, an assessment, a rejection. Once the superintendent's decision is disputed, the contract's dispute resolution clause governs the next step. That usually means a notice of dispute, a period of senior-level negotiation, sometimes mediation, and then expert determination, arbitration or litigation, depending on the form. Missing a step in that clause can have its own consequences, so read it as closely as the EOT clause.
Where the contract does not resolve the matter, construction contract disputes in New South Wales go to forums matched to the work and the stakes. Residential building claims are commonly heard in NCAT. Commercial delay disputes of substance go to the Technology and Construction List of the Supreme Court or the District Court, and some go to arbitration where the contract requires it. The forum choices are mapped in our guide to resolving a construction dispute in New South Wales. Early dispute advice is most valuable at the notice-of-dispute stage, while mediation, expert determination or a negotiated outcome is still cheaper than a hearing.
When to stop negotiating and start court proceedings is its own decision, and it should be made with the contract's dispute clause and the limitation clocks in view.
A contractor that suspends work for non-payment may create its own delay, and whether that suspension is justified is a separate question. Under section 27(1) of the SOP Act, the statutory right arises only after at least 2 business days have passed since notice of intention was given under section 15, 16 or 24. A claimant who suspends in accordance with that right is not liable, under section 27(3), for loss caused by not carrying out the work during the suspension. Section 27(2A) gives a separate claim for loss or expense caused by the respondent removing work or supply during that suspension. The effect on delay and liquidated damages is covered in our analysis of suspension of work under the SOP Act and liquidated damages in NSW.
Where a principal calls on a bank guarantee to recover LDs, whether a court will restrain that call is a separate question again. We outline the approach to restraining a call on a bank guarantee in our dispute resolution guide.
The clocks that decide a delay file
Eight clocks run on the same delay, from different triggers. Most are contractual, some are statutory, and none pauses for the others.
Clock | Source | Trigger | Period | Consequence if missed | Currency note |
EOT notice | Contract | Delay event, or when the contractor became aware of it | Contractual notice period | Possible loss of entitlement | — |
EOT claim particulars | Contract | The notice | Contractual period for particulars | As above | — |
Superintendent assessment | Contract | The claim | Contractual assessment period | Reserve-power and deemed-decision issues | — |
Progress-payment due date | SOP Act ss 11(1A), 11(1B), 11(1C) and 11(8) | Payment claim made under Part 3 | Principal to head contractor, other than an exempt residential construction contract: 15 business days after the payment claim, or an earlier contractual date (s 11(1A)). Subcontractor, other than an exempt residential construction contract: 20 business days after the payment claim, or an earlier contractual date (s 11(1B)). Exempt residential construction contract: the contractual due date, or 10 business days after the payment claim if the contract is silent (s 11(1C)). | Under s 11(8), a later contractual date has no effect for a payment under s 11(1A) or s 11(1B). Section 11(8) does not apply to s 11(1C). | Periods reflect the in-force business-day text. |
Payment schedule | SOP Act s 14(4) | Payment claim served | Contract time or 10 business days, whichever expires earlier | Liability for the claimed amount on the due date for the progress payment | Reflects the in-force business-day text. Check whether the working-day amendment has commenced. |
Adjudication application | SOP Act s 17 | Payment schedule or non-payment | 10 business days after receiving the payment schedule (s 17(3)(c)); 20 business days after the due date if a scheduled amount is unpaid (s 17(3)(d)); 10 business days after the end of the 5-business-day period in section 17(2)(b), where no schedule was provided (s 17(3)(e)). That route is available only if the claimant first served written notice, within 20 business days after the due date, of its intention to apply for adjudication: section 17(2)(a). | Loss of adjudication for that claim | Reflects the in-force business-day periods. Check whether the working-day amendment has commenced. |
HBA warranty proceedings | HBA ss 3B, 18E(1)(b)–(e), 18E(1A) and 18E(4) | Completion where the work is complete; otherwise termination, cessation or the contract date under s 18E(1)(d) | 6 years for a major defect as defined in s 18E(4); 2 years otherwise; a further 6 months under s 18E(1)(e); a possible extension under s 18E(1A) | Proceedings are out of time only after the applicable period | Current. For new buildings in strata schemes, completion is fixed under s 3C, not s 3B (s 3B(1A)). |
Contract / tort limitation | Limitation Act 1969 (NSW) s 14(1)(a)–(b) | Accrual of the cause of action | 6 years | Right and title extinguished under s 63(1), subject to the section’s exceptions | Applies to a contract not made by deed, and to tort. Deeds and contribution claims are dealt with separately. Section 14(1)(a) excludes a cause of action founded on a deed, and section 14(2)(a) excludes a cause of action to which section 19 applies. Section 14(2)(b) takes out a contribution claim to which section 26 applies. For contribution under section 5(1)(c) of the Law Reform (Miscellaneous Provisions) Act 1946 (NSW), section 26(1) of the Limitation Act sets the period as the first to expire of 2 years from accrual of the contribution claim and 4 years from expiry of the limitation period for the principal claim. |
Drafting and administering a time regime that works
Who this is for: principals, superintendents, contractors and subcontractors setting up or running the time regime.
The NSW cases show that most delay disputes are decided by choices made at contract formation and in the first week after an event. This section turns those choices into two checklists, one for each side of the contract. If you want construction law advice on your time regime before you sign, Merlo Law can check the proposed contract and special conditions against the points below.
For principals and superintendents
Four drafting decisions and three administration habits do most of the work.
On drafting, start with an EOT clause that covers every principal-risk event, including a catch-all for the principal's acts, omissions and breaches. Its purpose is to prevent the argument that time is at large. Second, draft the reserve power deliberately. Decide whether it is for the principal's benefit only, whether it carries a duty to act honestly and fairly, and whether you want the Growthbuilt formulation. Then make the words say exactly that. Third, set a notice window that is workable: short enough to give early warning, not so short that it invites unfair-terms scrutiny on a standard-form subcontract or makes compliance unrealistic. Fourth, include a concurrency clause that says how overlapping causes are treated. Silence leaves it to the overall-effect analysis. If the principal is a developer or special-purpose vehicle administering the contract itself, without an independent superintendent, Probuild applies to it directly: a party holding the power to extend time is likely to be obliged to use it for delay it caused, unless the drafting clearly says otherwise.
On administration, decide every claim within the contractual assessment period, with written reasons. Record the reserve power: when you consider it, whether you exercise it, and why, for each identified principal-caused delay. Keep the certifier independent: the principal should not instruct the superintendent on assessments, and the file should show that it didn't.
For contractors and subcontractors
The contractor's side of the regime is about systems, not advocacy.
Set up a diary system for notice windows, so each event starts a clock on the day it happens. Keep a claim template that meets the contract's content requirements (event, cause, critical-path effect, days claimed, supporting program) and can be filled in within hours, not weeks. Issue program updates at the contract's intervals, with narrative that names principal delay events as they arise. Keep a single delay register as described in the section on the records that win or lose a delay claim.
Refuse verbal acceleration. Ask for a written direction and, if none is given, confirm the instruction in writing the same day with a reservation of rights.
For subcontractors, find out the head-contract windows and work to them, not just to the subcontract windows. Read the reserve-power clause at tender. If it contains Growthbuilt wording, your own notices are your only protection, and that should be reflected in your price and your procedures.
How delay and disruption claims play out on NSW jobs
Four illustrative NSW fact patterns follow. The orientation table at the start of this guide matches each reader position to one of them. They are composites for teaching, not client matters, and each closes with the lesson it teaches.
Commercial warehouse on AS 4000: late design information and a missed notice
The notice window closed before anyone focused on time, and that decides this one.
The principal's design information for the warehouse structure arrives six weeks late. The contractor's crews stand down and then re-sequence. Everyone knows why the job is behind, but the contractor's EOT notice is not given within the contractual notice period. When practical completion slips, the superintendent declines to exercise the reserve power, and the principal starts deducting LDs.
The analysis runs through the decision path in the section on contracting out. Turner v Austotel is against the contractor: it had a route to time for the principal's late information and didn't use it, so it is not "prevented". Peninsula Balmain may be for it. If the reserve power is in the unamended AS 4000 form and the superintendent is bound to act honestly and fairly, the superintendent may be obliged to extend time for the principal-caused delay despite the missed notice. The critical question is whether the principal amended the reserve power in the special conditions to make it for the principal's benefit only, discretionary, or not obligatory. If it did, the question moves to Growthbuilt. The contractor also needs delay evidence: program updates showing the design release on the critical path, and RFIs showing the dates. Waiver or estoppel is a fallback if the principal's minutes acknowledged the delay without insisting on notice.
Lesson: give notice at the event, then pin down the reserve power in writing. The missed notice converts a straightforward EOT into an argument about the superintendent's duty.
Fitout subcontract with an "absolute discretion" clause
On facts like these, subcontractors often misread their position, assuming the head contractor must extend time for its own delay.
A fitout subcontractor on a commercial job is delayed because the head contractor's other trades don't vacate the floors on time. The subcontract gives the head contractor absolute discretion to extend time and says the head contractor has no obligation to extend time or to consider doing so. The subcontractor gives no EOT notice, relying on an understanding that "everyone knows the ceilings were late". The head contractor levies subcontract LDs.
On Growthbuilt-style drafting, prevention is likely excluded if no claim was made. The combination of absolute discretion and an express no-obligation clause leaves no room for the Probuild implied duty. The subcontractor's arguments narrow to waiver or estoppel on the facts. If the subcontract is a standard form issued to a small business, it may also argue that the clause is unfair under the ACL. That argument depends on the statutory criteria, the thresholds and a fact-heavy analysis of the head contractor's legitimate interests. It is not a quick answer.
Lesson: the subcontractor's only reliable protection is its own notices, given within its own windows, whatever it believes about who caused the delay. Standard-form status under the ACL is worth checking, but it is a contest, not a safety net.
If your subcontract contains absolute discretion wording, Merlo Law can review it before your next notice is due and set out the notice steps that protect you under it.
Civil works: latent rock, wet weather and constructive acceleration
When events overlap, the analysis has to be done event by event, and money has to be claimed separately from time.
On a civil job under a Transport for NSW-style contract, the contractor meets rock not shown in the geotechnical information. Weeks later it loses days to wet weather above the contract allowance. It gives notices for both. The EOT for the rock is refused on the basis that the rock was foreseeable. The weather EOT is partly granted. Facing LDs, the contractor adds crews and extends shifts, and writes to the principal that it is accelerating under protest.
The analysis starts with qualifying causes. Is rock a latent condition on this contract's risk allocation and site-investigation clauses? Is the weather above the allowance on the contract's measure? Next is the concurrency clause. Did any contractor-caused delay overlap either event, and how does the contract treat that? Then the money: prolongation for the extended period is only claimable if a delay-costs clause covers latent conditions (weather is commonly excluded), and disruption from the weather needs productivity evidence. The acceleration claim is the weakest part. Constructive acceleration is unsettled in NSW, and the contractor needs to show the EOT entitlement, the wrongful refusal, the causal link to the acceleration, and the cost. The written protest helps. Pursuing the rock EOT through the dispute clause remains the primary route.
Lesson: run the EOT, and don't treat acceleration as a substitute. Acceleration costs are recoverable only if you win the time argument you should have been pressing all along.
Residential new dwelling: owner variations and the timing warranty
On residential work the statute sits behind the contract, so the builder has to win the argument on both.
Under an HIA new-dwelling contract, the owners ask for a series of variations during framing and fit-off: a changed kitchen, an added ensuite window, upgraded flooring. The builder prices each variation but doesn't record a time effect on most of them. Completion runs late. The builder claims an EOT for the variations. The owners say the builder breached the timing warranty in s 18B(1)(d) of the HBA and claim rent and alternative accommodation.
The builder's case depends on proving that each variation delayed completion and that the delay was claimed under the contract. Variations with an agreed written time effect are straightforward. Those without are an argument, and the owners will say the time was absorbed. Behind the contract sits the statutory timing warranty, which s 18G of the HBA protects from being contracted out. The dispute will likely be run in NCAT. If an owner refuses to sign a variation during the job, whether the builder can stop work is its own question, covered in our analysis of stopping work over an unsigned residential variation.
Lesson: tie time to every variation in writing, including "nil" where that is the answer. On residential work the timing warranty is always in the background, and the builder's written time assessment is its main defence.
Failure-mode library: how delay claims are lost
The failures below are collected in one place because each is a process failure, not a legal one, and each is preventable.
Delay claims are commonly lost in these ways:
The notice was given when the claim was made, not when the event happened. By then the window had closed, and Turner v Austotel did the rest.
The claim asserted delay without showing critical-path impact. Showing that work was delayed is not showing that completion was delayed.
The contractor relied on prevention after choosing not to claim. In NSW, a contractor with a route to time that didn't use it is generally not "prevented".
A global claim was made with no allocation of cost to cause. If any part of the overrun had another cause, the whole claim was exposed.
The contractor accelerated on a verbal site instruction. Without a written direction, the acceleration looked voluntary.
The subcontract's notice windows were longer than the head contract's. The head contractor learned of the delay after its own window had closed.
The superintendent sat on the reserve power without recording reasons. Its silence was later reconstructed as a failure of the honest-and-fair duty.
The contractor treated an EOT as an entitlement to money. The EOT was for a no-cost cause, and no delay-costs clause applied.
Program updates were missing, or were produced after the event. The delay analysis then rested on reconstruction, and its credibility went with it.
The SOP payment schedule deadline was missed while an EOT was "under assessment". Liability under s 14(4) of the SOP Act attached regardless of the time dispute.
Conclusion
The order that matters is the one this guide follows. First, identify which of the four claims you are making or answering (delay, disruption, prolongation or acceleration), because each is proved differently. Next, find the qualifying cause and confirm the notice was given at the event, within the contractual notice period. Then read the reserve-power clause and place it on the Peninsula Balmain, Probuild or Growthbuilt spectrum before arguing prevention. Prove critical delay from the programs and records made at the time, and apply the contract's concurrency rule. Only then look for the separate clause that pays for time. And run the SOP Act, HBA and limitation clocks alongside all of it, because none of them waits.
That order produces the right outcome because each step removes an argument the other side would otherwise have. A notice given at the event removes Turner v Austotel. A written reserve-power request removes silence as a defence. A contemporaneous program removes the attack on credibility. A cost claim allocated to causes removes the global-claim problem. Contractors who reverse the order, arguing prevention first and gathering evidence last, tend to lose claims they should have won.
Related reading: liquidated damages in NSW construction contracts and our guide to construction contracts in NSW.
Currency notes (as at 30 September 2026)
Building (Approvals and Practitioners) Act 2026 (NSW). The Act received assent on 14 August 2026. Under section 2, only Schedule 3[20] and [45] commenced on assent. The remainder, including section 202, commences on a day or days to be appointed by proclamation. Section 202 provides for the repeal of the Building and Development Certifiers Act 2018 (NSW), the Building and Development Certifiers Regulation 2020 (NSW), the Design and Building Practitioners Act 2020 (NSW), the Design and Building Practitioners Regulation 2021 (NSW) and the Environmental Planning and Assessment (Development Certification and Fire Safety) Regulation 2021 (NSW). It does not repeal the HBA, so sections 18B(1)(d), 18E and 18G remain in force. Section 12(7) of the BAP Act only permits regulations to modify how the BAP Act and the HBA apply to prefabricated buildings.
Fair Trading and Building Legislation Amendment Act 2026 (NSW) (Act No 28 of 2026). The Act received assent on 14 August 2026. Schedule 1 provides for “business days” to be replaced by “working days”. When this guide was last checked against the in-force text (29 September 2026), section 14(4) of the SOP Act still used business days. Before counting a statutory deadline, check whether the enacted items have commenced. Either way, section 4(1) already excludes a Saturday, Sunday or public holiday, and 27, 28, 29, 30 or 31 December, from “business day”. The label change does not create that exclusion.
How Merlo Law can help
The matters this practice handles on NSW delay files follow the sequence above.
They include:
preparing and assessing EOT claims under AS 4000, AS 2124, AS 4902, GC21, Transport for NSW and bespoke contracts
advising superintendents and principals on the reserve power
advising contractors on missed notices, waiver and estoppel
building delay-cost, disruption and acceleration claims on the contract
aligning subcontract time regimes with head contracts
running delay issues through payment claims, schedules and adjudication, NCAT for residential work, or court and arbitration for commercial disputes
The right time to seek advice is at the delay event, while the notice window is still open. The next best time is before the first liquidated damages deduction or the payment schedule deadline. If a delay is building on one of your projects, send Merlo Law the executed contract (including special conditions), the delay register or site diary for the period, and the last accepted program. We will tell you which notices are still open, whether the reserve power is live, and what to put in writing this week.
This guide is general information about New South Wales law as at 30 September 2026. It is not legal advice and does not take your contract or circumstances into account. Construction contracts are frequently amended, and the outcome of a delay claim turns on the executed contract and the facts. Obtain advice on your specific matter before acting or deciding not to act.
FAQ
What is an extension of time claim in NSW construction?
It is a contractual claim by the contractor to move the date for practical completion because a qualifying cause, such as a principal's act, a variation, a latent condition or weather above an allowance, delayed the critical path. It protects against liquidated damages for the extended period. It does not, by itself, entitle the contractor to be paid for the delay.
Does the prevention principle still apply if I missed the EOT notice deadline?
Generally not in NSW, if the contract gave you a route to time and you didn't use it (Turner v Austotel). Your remaining arguments are usually waiver or estoppel, or a reserve power that the superintendent or head contractor was obliged to exercise (Peninsula Balmain; Probuild). Clear "absolute discretion, no obligation" drafting can remove even that (Growthbuilt).
Can a superintendent grant an extension of time if the contractor didn't claim one?
Often yes, if the contract has a reserve power. In Peninsula Balmain, the Court held that a superintendent exercising such a power was required to act honestly and impartially, and that on the facts an extension should have been granted for principal-caused delay despite no compliant claim. Many principals now amend the power, so check the special conditions carefully.
Can I claim delay costs as well as an extension of time in NSW?
Only if there is a separate entitlement: a delay-costs clause covering that cause, a variation that includes time-related costs, or damages for the principal's breach, in each case subject to the contract's exclusions and caps. Neutral causes such as weather commonly give time without money.
What does "time at large" mean in a construction contract?
It means the completion date has fallen away, usually because the principal prevented completion and the contract had no working mechanism to extend time for that. The contractor must then reach practical completion within a reasonable time. LDs fall away, but general damages for delay beyond a reasonable time may still be recoverable.
Who bears concurrent delay under a NSW construction contract?
The contract decides first. A concurrency clause may deny time, give time without money, or apportion the delay. If the contract is silent, the NSW starting point looks at the overall effect on completion, so a small principal delay does not wipe out the contractor's own substantial delay.
This guide is for informational purposes only and does not constitute legal advice. For advice tailored to your specific circumstances, please contact Merlo Law
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