In brief: The table below sets out the notice and claim periods for extension of time under the standard construction contracts most used in the UK, the Middle East, Australia and the US. FIDIC requires notice within 28 days, NEC4 within 8 weeks, AIA A201 within 21 days and AS 4000 a claim within 28 days. JCT has no fixed notice period but requires notice “forthwith”. Amendments change these periods on most projects, so always check your own contract.
Notice and claim periods by contract
| Contract | Notice of delay or claim | Detailed claim or particulars | Response from the other side | Time bar in the standard form? |
|---|---|---|---|---|
| FIDIC Red Book 1999 Sub-Clauses 8.4, 20.1 | 28 days after the contractor became aware, or should have become aware, of the event | Fully detailed claim within 42 days of becoming aware. Monthly interim claims if the effect continues | Engineer responds within 42 days of receiving the claim | Yes. A late notice means no extension and the employer is discharged |
| FIDIC Red Book 2017 Sub-Clauses 20.2, 3.7 | Notice of Claim within 28 days of becoming aware (20.2.1). The Engineer may say within 14 days that the notice was late (20.2.2) | Fully detailed claim within 84 days of becoming aware (20.2.4). Monthly updates if the effect continues (20.2.6) | Engineer has 42 days to reach agreement, then 42 days to make a determination (3.7.3) | Yes, for the 28-day notice and for the statement of legal basis within 84 days |
| NEC4 ECC Clauses 61 to 62 | Notify a compensation event within 8 weeks of becoming aware (61.3). Not required where the event arises from a Project Manager instruction or notification | Quotation within 3 weeks of the instruction to submit one (62.3) | Project Manager replies to a notification within 1 week and to a quotation within 2 weeks. If still silent 2 weeks after the contractor’s reminder, it is deemed accepted | Yes, for the 8-week notice (61.3) |
| JCT SBC and DB 2016 SBC clauses 2.27 to 2.29 | Notice “forthwith” when it becomes reasonably apparent that progress is or will be delayed | Particulars and an estimate of the delay with the notice or as soon as possible after it, kept up to date | Decision within 12 weeks of receiving the required particulars. Review within 12 weeks after practical completion | No, unless amended. Many amendments add one |
| JCT 2024 | As JCT 2016 | As JCT 2016. The employer side may ask for further information within 14 days | Decision within 8 weeks | No, unless amended |
| AS 4000-1997 Clause 34 | Notify the Superintendent promptly when it becomes evident that something may delay the work (34.2) | Written claim within 28 days after the contractor should reasonably have become aware of the delay (34.3) | Superintendent directs within 28 days of the claim (34.4). May also extend time on its own initiative (34.5) | In effect yes: entitlement depends on the claim being made in time |
| AS 2124-1992 Clause 35.5 | Notify promptly | Written claim within 28 days after the delay occurs | Superintendent assesses the claim. May also extend time on its own initiative | In effect yes |
| AIA A201-2017 Article 15 | Claim within 21 days after the event, or after the claimant first recognises the condition (15.1.2) | A claim for time must include an estimate of the probable effect of the delay on progress | Initial Decision Maker acts within 10 days of receiving the claim (15.2.2) | Yes, subject to state law |
| US federal contracts FAR 52.243-4, Contract Disputes Act | Written notice within 20 days of a constructive change, or costs incurred earlier are not recoverable (52.243-4(d)). Assert a written change order within 30 days (52.243-4(e)) | A claim under the Contract Disputes Act within 6 years of accrual (FAR 33.206). Certification required above $100,000 | Contracting officer decides within 60 days, or for claims above $100,000 states when a decision will be made (FAR 33.211) | Partly: the 20-day limit applies to costs before notice |
Periods are as written in the unamended standard forms. Particular or special conditions often shorten them or add requirements. Last checked: November 2026.
How the periods are counted
- FIDIC: “day” means a calendar day. The 28 days run from when the contractor became aware, or should have become aware, of the event, not from when the delay ends.
- NEC4: periods are in weeks. The 8 weeks run from when the contractor became aware of the event.
- JCT: there is no fixed number of days for the notice, but “forthwith” means promptly. A late notice can still weaken the claim and can be relevant to mitigation.
- AS 4000 and AS 2124: the 28 days are calendar days unless the contract says otherwise. Many special conditions use business days instead.
- US contracts: state law may limit how strictly a notice clause is applied. Federal boards and courts sometimes excuse late notice where the government knew of the facts and was not prejudiced.
Frequently asked questions
What happens if I miss the FIDIC 28-day notice?
Under both the 1999 and 2017 Red Books, the contractor loses its entitlement to an extension of time and additional payment for that event, and the employer is discharged from liability. Under FIDIC 2017, Sub-Clause 20.2.5 allows the contractor to argue that a late notice was justified, and the Engineer, and later the DAAB or a tribunal, decides.
Is the NEC4 8-week notice a strict time bar?
Yes. If the contractor does not notify within 8 weeks of becoming aware, it loses the right to a change in the Prices and the Completion Date. The time bar does not apply where the event arises from the Project Manager giving an instruction or notification, because the Project Manager should have notified it.
Does JCT have a time bar for extension of time notices?
Not in the unamended JCT 2016 or 2024 forms. The contractor must notify “forthwith”, and the Architect or Contract Administrator can still grant an extension at the review after practical completion. Many bespoke amendments turn the notice into a condition precedent.
Which period applies if my contract is amended?
The amended period. Particular Conditions, special conditions and schedules of amendments override the standard wording. Read them before relying on any period in this table.
This table is general guidance, not legal advice. Check the notice and claim clauses of your own contract and take advice on the governing law.
Related: EOT claims in the UAE under FIDIC 2017 · NEC4 compensation events · Free EOT claim checklist and registers
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