Extension of Time Claim Process: Step-by-Step Guide for Contractors and Employers

A contractor on a $200M hospital project hits unexpected ground conditions. Tunnelling work stops. The delay is real, the cost is mounting, and the completion date is sliding. The contractor submits an extension of time (EOT) claim three months later. The employer rejects it. Not because the delay didn’t happen, but because the notice was late, the schedule analysis didn’t link the delay to the critical path, and the supporting documentation was a folder of unsorted emails rather than a structured contemporaneous record. The claim goes to dispute, where it takes 18 months and $2M in legal fees to reach a determination that could have been avoided with a proper EOT process.

That scenario is common. Flyvbjerg’s database of 16,000 projects across 136 countries, presented in How Big Things Get Done, shows that 91.5% of major projects run over budget, over schedule, or both. Delays happen. The EOT process exists to deal with them fairly. But the process only works if both the contractor and the employer follow it correctly. This article walks through the complete EOT claim process from the delay event to the final determination, covering both the contractor’s submission obligations and the employer’s assessment responsibilities.

What Is an Extension of Time (EOT) Claim?

An extension of time claim is a formal request by the contractor to extend the contract’s completion date. It’s not a request for money. It’s a request for time. The contractual mechanism protects the contractor from liquidated damages for delays that aren’t its fault, while giving the employer certainty about when the project will finish.

An EOT claim is distinct from a delay damages claim and from prolongation costs. The EOT deals with time only: moving the completion date. Prolongation costs compensate the contractor for the additional expense of being on site longer. They’re often claimed together, but they’re separate entitlements with different tests.

Per the SCL Delay and Disruption Protocol, 2nd Edition, Core Principle 2 (Purpose of EOT), an extension of time has two principal purposes: first, to relieve the Contractor of liability for liquidated damages for the period of delay caused by the relevant event; and second, to establish a new completion date against which further delays can be measured.

Callout box: 91.5% of major projects run over budget or over schedule, according to Flyvbjerg’s database. Delays are the norm, not the exception. The EOT process is how contracts manage that reality.

The EOT Claim Process: Overview

The EOT process has six phases. Each one has contractual requirements, and missing any of them can undermine the claim or the assessment.

The entire process, from the delay event to a final determination, can take anywhere from a few weeks to several months depending on the contract, the complexity of the delay, and the quality of the submission. On poorly managed projects with weak records and contested claims, it can stretch into years.

Step 1: Identify the Delay Event and Contractual Grounds

Every EOT claim starts with a delay event. But not every delay event entitles the contractor to an extension of time. The starting point is always the contract: what does it say about which events qualify?

Common grounds for an EOT include:

• Variations or changes to the scope of work
• Late design information or instructions from the employer
• Unforeseen physical conditions (differing site conditions)
• Force majeure events
• Employer defaults or breaches
• Statutory authority delays
• Adverse weather beyond the contractual threshold

The key question is: does the contract list this event as an EOT ground? If the answer is yes, the contractor has a potential entitlement. If no, the delay may be the contractor’s risk regardless of cause.

Different standard form contracts define EOT grounds differently. Here’s how the major forms compare:

Mapping the delay to the contract clause

The contractor must identify the specific clause under which the EOT is claimed. A claim that says “we were delayed” without citing the contractual provision won’t survive assessment. The SCL Protocol (Guidance Part A, paragraph 13) requires the claim document to explain the legal basis for entitlement under the contract or at law, and to explain the cause of the delay and the remedies claimed.

From the employer’s perspective, this means the first thing to check in a received claim is whether the delay event is listed as an EOT ground in the contract. If the claimed ground doesn’t match a listed event, the claim fails at the first hurdle.

Step 2: Serve the Notice of Delay

Notice is the gatekeeper of the EOT process. Miss the notice requirement, and the claim can be barred regardless of the delay’s merit. The SCL Protocol, Core Principle 3 (paragraphs 3.1–3.3), addresses contractual procedural requirements relating to notices, particulars and substantiation. Paragraph 3.1 notes that some standard forms make the giving of notice a condition precedent to entitlement.

Notice periods vary by contract form:

What the notice must contain

A valid notice of delay should include:

1. Identification of the delay event, including the date it occurred or started
2. The contractual clause under which the EOT is claimed
3. A description of the expected impact on the programme, including which activities are affected
4. An estimate of the time extension required, however preliminary
5. Reference to contemporaneous records that support the claim

Common notice mistakes

• Late notice. The most fatal error. Under FIDIC, the 28-day clock starts when the contractor knew or should have known of the event, not when it finishes. Waiting until the end of a prolonged event can mean the notice is too late.
• Vague notice. A notice that says “weather delays” without specifying which weather event, when it occurred, and which activities it affected may not satisfy the contractual requirement.
• Wrong recipient. Sending notice to the wrong party (the client instead of the engineer, for instance) may not satisfy the contractual notice requirement.
• No programme reference. A notice that doesn’t identify the affected activities on the programme makes it difficult to later demonstrate critical delay.

From the employer’s side, if you receive a late or vague notice, don’t just ignore it. Respond in writing, noting the deficiency. Some contracts allow the engineer or architect to waive strict compliance with notice provisions, but this should be documented (the SCL Protocol does not specifically address waiver; it treats compliance with notice requirements as a potential condition precedent to entitlement at Core Principle 3, paragraph 3.1).

Step 3: Record and Preserve Contemporaneous Evidence

Contemporaneous records (records made at the time events occurred, not reconstructed later) are the gold standard for establishing what actually happened on the project. The CIOB Guide to Good Practice in the Management of Time, Chapter 5, emphasises that contemporaneous records are the most reliable form of delay evidence. Retrospectively created records carry less weight because they’re vulnerable to challenges about accuracy and bias.

A contractor who waits until the claim is being prepared to compile evidence is at a severe disadvantage. Memories fade. Records get lost. The SCL Protocol, paragraph 11.4, requires the claimant to demonstrate cause and effect on the critical path; that demonstration is far more convincing when supported by records made at the time. From the employer’s perspective, contemporaneous records are equally important for the defence: if the employer can show the contractor was already behind before the claimed event, the EOT claim may fail on causation.

Step 4: Assess the Impact on the Schedule

An EOT claim must demonstrate that the delay event actually affected the completion date. This means connecting the delay to the critical path through structured EOT claim analysis. A claim that says “we were delayed by four weeks on this activity” without showing that the delay pushed out the project finish date is incomplete.

Per the SCL Protocol, Guidance Part A paragraph 13, the claim must explain the cause of the delay and the remedies claimed. AACE International RP 29R-03, Section 1.4 (Taxonomy and Nomenclature) and Section 3 (Method Implementation Protocols), classifies schedule analysis methods by timing (prospective vs retrospective) and basic approach (observational vs modeled).

Choosing the right delay analysis method

The SCL Protocol (paragraph 4.12, Core Principle 4) recommends Time Impact Analysis as the methodology for contemporaneous assessment of EOT applications during the project. The 2nd Edition (Introduction §K(c)) removed the expressed preference for TIA where the analysis is carried out time-distant from the delay event. The recommended approach analyses the delay event against the programme as it stood at the time, rather than using hindsight. However, the choice of method depends on the circumstances, the available data, and sometimes the contract itself.

Linking delay to the critical path

A delay only entitles the contractor to an extension of time if it affects the completion date, which means it must affect the critical path. Per the SCL Protocol, Core Principle 8 (paragraphs 8.2 and 8.6), delay to an activity with float doesn’t automatically delay completion. An EOT is generally only due where the Employer Delay is critical to the contract completion date. Only when float is exhausted and the activity becomes critical does the delay begin to affect the completion date.

This is where schedule analysis becomes essential. The claim must show the before-and-after: the programme without the delay event, and the programme with the delay event inserted. A rigorous baseline vs current schedule comparison underpins this exercise, so the time difference between the two completion dates can be defended as the quantum of EOT.

Float ownership is a separate but related issue. Some contracts specify that float belongs to the project (shared), while others treat it as belonging to whoever needs it first. The SCL Protocol, Core Principle 8 (paragraph 8.5), takes the position that float is not time for the exclusive use or benefit of either the Employer or the Contractor (unless the contract expressly provides otherwise). Check your contract.

Step 5: Prepare the EOT Claim Submission

A well-structured EOT claim is easier to assess and harder to reject.

1. Executive Summary
2. Background and Project Description
3. Contractual Basis
4. Factual Narrative of Delay Events
5. Schedule Analysis and Quantum
6. Supporting Appendices
   - Contemporaneous records
   - Programme extracts (before and after)
   - Contract clause extracts
   - Correspondence
   - Weather data
   - Photographs

The executive summary should be one or two pages stating the claim: what delay event occurred, what clause applies, how many days of extension are claimed, and the new completion date.

The contractual basis cites the specific clause, the EOT ground, and notice compliance. This answers the procedural question before the substantive analysis starts.

The factual narrative tells the story of the delay in chronological order, supported by contemporaneous records. It should read like a timeline, not an argument.

The schedule analysis is the technical heart of the claim. It must show the unimpacted programme, the delay event inserted, and the resulting impact on completion. Include the full TIA or whatever methodology was used.

The supporting appendices contain the evidence. Every statement of fact in the narrative should be traceable to a contemporaneous record in the appendices.

The Boston Central Artery/Tunnel Project (the Big Dig) experienced 16 years of delays and cost triples. The EOT claims on that project generated thousands of pages of analysis because the delays were interrelated and the factual background was contested. Simpler projects produce simpler claims. The key is proportionality.

Step 6: Employer Assessment of the EOT Claim

The employer’s assessment is a review process, not a rubber stamp. The assessor (engineer, architect, superintendent, or project manager, depending on the contract) must verify that the claim satisfies both procedural and substantive requirements.

The assessment process

What to check

1. Procedural compliance. Was notice given on time? Is the claimed ground a listed EOT event? Is the claim submitted in the required format and time frame?
2. Causation. Does the delay event actually link to the critical path through the schedule analysis? Or does the programme show the contractor was already behind for other reasons?
3. Quantum. Is the time extension reasonable? Does the schedule analysis support the number of days claimed?
4. Concurrent delay. Were there other delays happening at the same time? If the contractor was also in delay, the SCL Protocol, Core Principle 10 (paragraph 10.12), states that where concurrent delay has been established, the Contractor should be entitled to an EOT for the Employer Delay to Completion; the Contractor Delay should not reduce the amount of EOT due. Compensation, however, is treated separately under Core Principle 14.
5. Mitigation. Did the contractor take reasonable steps to mitigate the delay? Most contracts require the contractor to proceed with due diligence and minimise delay.

What we found: A headline EOT figure can mask concurrent contractor-caused delay sitting on the same critical path. Where an employer event drove the critical delay for part of a window, and an independent contractor cause drove the critical delay for the rest, the SCL Protocol’s Core Principle 10 separates the two: the contractor is entitled to EOT for the employer’s portion, but the concurrent contractor portion does not increase the entitlement.

What it means: Without separating each cause’s independent critical-path effect, an assessor will tend either to over-grant (treating the full elapsed window as employer-caused) or to under-grant (rejecting the claim entirely once contractor causes show up). Both outcomes create downstream disputes; the careful separation is what makes the determination defensible.

Independent schedule analysis

For complex claims or claims where the analysis is disputed, the employer should commission an independent schedule analysis. This involves running the delay analysis methodology independently, using the contemporaneous programme data, to verify or challenge the contractor’s conclusions.

AACE RP 29R-03, Section 1.5 (Underlying Fundamentals and General Principles) and Section 2 (Source Validation Protocols), set out general requirements for forensic schedule analysis including reliance on validated baseline, as-built, and update data.

Time limits for assessment

Some contracts impose time limits on the assessor. Under FIDIC Red Book, Clause 20.1, the engineer must determine the extension of time within 42 days after receiving the claim. Under JCT, the architect or contract administrator should make a determination within a reasonable time. Under NEC4, the project manager must assess a compensation event within one week of receiving the quotation (Clause 62.3), though this applies to the contractor’s quotation rather than a full EOT claim.

From the employer’s perspective, delayed assessment can be a breach of contract and may give the contractor grounds for a further claim.

Step 7: Grant, Partial Grant, or Rejection

The determination concludes the EOT process. There are three possible outcomes.

Full grant

The assessor agrees with the claim in full: the delay event qualifies, the schedule analysis demonstrates critical delay, and the quantum of days is correct. The completion date is extended accordingly.

Partial grant

The assessor agrees with the contractual entitlement but not the full quantum. This might happen when the schedule analysis shows less critical delay than claimed, or when concurrent contractor delay reduces the entitlement.

Partial grants are common. They reflect the reality that the contractor’s analysis doesn’t always precisely match the independent assessment. The key is that the determination explains exactly what time is granted and why, and what time is rejected and why.

Rejection

The claim is rejected in full. Common reasons include:

Dispute resolution

If the contractor disagrees with the determination, the contract’s dispute resolution provisions apply. Under FIDIC, this is the Dispute Adjudication Board (DAB). Under JCT, it’s adjudication. Under NEC, it’s adjudication or the dispute resolution process in Option W. Under Australian standard forms, it’s typically adjudication under the relevant Security of Payment legislation or agreed dispute resolution.

The SCL Protocol, Core Principle 4 (paragraphs 4.5–4.6) and Core Principle 7 (Incremental review of EOT), strongly discourages a ‘wait and see’ approach and recommends early/incremental determination of EOT claims, which makes later dispute resolution more complex and more expensive.

Common Mistakes in the EOT Claim Process

Mistakes in the EOT process aren’t just procedural inconveniences. They’re the difference between a valid claim and a rejected one. Here are the most common:

1. Late notice of delay. The number one reason claims fail. The contractor waits to see how bad the delay will be before giving notice. By then, the contractual window has closed.

2. No schedule analysis. A factual narrative without schedule analysis is a story, not a claim. The claim must demonstrate critical path impact through recognised delay analysis methodology.

3. Using the wrong methodology. Applying a retrospective analysis (as-planned vs as-built) to a contemporaneous EOT claim doesn’t follow the SCL Protocol’s preference (Core Principle 4) for contemporaneous assessment using methods such as TIA.

4. Ignoring concurrent delay. Pretending concurrent delays don’t exist doesn’t make them go away. It makes the claim look dishonest.

5. Weak contemporaneous records. A claim built on retrospectively assembled evidence is easier to challenge than one built on records made at the time.

6. Not linking delay to the critical path. A delay to a non-critical activity with float doesn’t entitle the contractor to an EOT, regardless of how real the delay is.

7. Employer failing to assess on time. The employer has contractual obligations too. A delayed assessment can itself become a breach.

Callout box: The Berlin Brandenburg Airport opened nine years late. The official inquiry found that delays were compounded by poor contract management, including inadequate programme tracking and unresolved EOT claims. When the EOT process breaks down, disputes escalate, costs increase, and the project relationship deteriorates. Flyvbjerg and Gardner document this pattern extensively in How Big Things Get Done.

Tools for Managing the EOT Process

Key Takeaways

• Give notice immediately. The contractual clock starts when you knew or should have known of the delay, not when it’s convenient to tell someone.
• Map every claim to a specific contract clause. General claims without contractual grounding don’t survive assessment.
• Keep contemporaneous records from day one. You can’t reconstruct them later.
• Use a recognised delay analysis methodology. The SCL Protocol and AACE RP 29R-03 are the references. State the methodology in the claim.
• Link the delay to the critical path. If the delay doesn’t affect the completion date, it doesn’t entitle the contractor to an EOT.
• Address concurrent delay honestly. Ignoring it invites rejection and undermines credibility.
• Employers must assess within the contractual timeframe. A delayed assessment is itself a breach.

The EOT process only works when both parties follow it. If you’re submitting a claim, the quality of your process determines whether you get the time you’re entitled to. If you’re assessing one, your job is to verify the claim against the contract, the programme, and the evidence. In both cases, the schedule analysis is the foundation.