The NEC4 eight-week time bar: how compensation events quietly expire

FIDIC's 28-day notice gets most of the attention in this trade. NEC's eight-week equivalent is quieter, sounds more generous, and catches teams just as often — usually teams who assumed that an early warning, a site diary entry or a mention in a progress meeting counted as notification. It does not. Here is how the mechanism works, where it does not apply, and the specific ways entitlement leaks away.

What clause 61.3 actually says

The NEC4 Engineering and Construction Contract puts the obligation on the contractor to notify a compensation event the Project Manager has not already notified. As Arbicon set out in their analysis of NEC4 notification, the clause provides that if the contractor "does not notify a compensation event within eight weeks of becoming aware that the event has happened, the Prices, the Completion Date or a Key Date are not changed unless the event arises from the Project Manager or the Supervisor giving an instruction or notification, issuing a certificate or changing an earlier decision" (Arbicon via PBC Today).

Two things in that sentence decide most disputes:

• Eight weeks is the outer limit, not a target. The consequence of missing it is binary: no change to money, time or Key Dates. There is no partial recovery for being a week late.
• The bar has a carve-out. Events arising from the Project Manager or Supervisor giving an instruction or notification, issuing a certificate or changing an earlier decision are the Project Manager's to notify under clause 61.1 — the contractor's eight-week clock does not bar those.

In NEC subcontracts the period is shorter still. NEC's own guidance notes the equivalent subcontract time bar is seven weeks, so a subcontractor's clock runs out before its contractor's does (NEC Contracts).

And beware amendments. Brodies LLP report seeing contracts in which the notification period had been cut from eight weeks to as little as one — the printed form is only the starting point, which is why the first thing to check on any NEC project is what your contract actually says (Brodies).

Which events can be time-barred

Not every compensation event is exposed to clause 61.3. Writing for NEC, Steve Goodwin of GVE Commercial Solutions identifies the clause 60.1 events that can be caught by the time bar — including late access, late Client-provided things, physical conditions, weather and Client liabilities — while the events triggered by instructions, notifications, certificates or changed decisions sit outside it because the Project Manager is obliged to notify those (NEC Contracts).

Goodwin's sharper point is about fairness in practice: for almost all of the time-barrable events, the Client's own team caused or controls the circumstance — a client that caused the detriment can still enforce the bar if the contractor is late. Whether or not that feels right, it is how the clause operates, and 39% of NEC users surveyed by his firm in 2019 saw nothing unfair in it. Relying on the other side's goodwill is not a strategy.

When does the clock start? "Aware that the event has happened"

NEC4 adjusted the trigger wording from NEC3: the eight weeks now run from the contractor "becoming aware that the event has happened" — a small but deliberate amendment, as Fenwick Elliott note in their dispute-resolution review of NEC4 (Fenwick Elliott). What the wording leaves open is the gap between belief and awareness: knowing something happened on site is not the same as recognising it as a compensation event, and the two can occur weeks apart. NEC Users' Group commentators have written about exactly this mismatch in clause 61.3 (Goodwin, Woodridge-Irving and Broome, NEC Users' Group Newsletter 116, January 2022, cited in the NEC article below).

The practical consequence: a team that dates its awareness from the moment the commercial manager recognised a claim may already be weeks behind a tribunal's view of when the event itself was known on site. The safe operating assumption is the earlier date — when the ground conditions were encountered, the access was not given, the information did not arrive — not the later date when someone connected it to clause 60.1.

The clocks that follow the notification

Notification starts a timetable that is easy to state and routinely missed. As Brodies summarise it: the Project Manager must reply within one week of the notification, saying whether the event is a compensation event. If there is no reply, the contractor may notify the failure — and if the failure continues for a further two weeks after that reminder, the event is deemed accepted (Brodies).

Note what deemed acceptance requires: silence alone at the one-week mark changes nothing. The contractor has to send the reminder to start the two-week deemed-acceptance period. A team that notifies and then waits politely has protected nothing.

An early warning is not a notification — and skipping it has its own price

The most common confusion on NEC projects is treating the clause 15.1 early warning and the clause 61.3 notification as interchangeable. They are separate obligations with separate sanctions.

An early warning is due "as soon as" either party becomes aware of any matter which could increase the Prices or delay Completion — before the eight-week clock is anywhere near expiry. And failing to give one is punished through assessment, not through a bar: under clause 61.5 the Project Manager states in the instruction to quote that an experienced contractor could have given an early warning, and under clause 63.7 the compensation event is then "assessed as if the Contractor had given the early warning" (Arbicon via PBC Today). Under the cost-based Options C, D, E and F, cost incurred only because a required early warning was not given can also fall into Disallowed Cost.

So a contractor can serve its clause 61.3 notification comfortably inside eight weeks and still watch the assessment collapse to a fraction of its costs — or to nothing — because the early warning that should have preceded it was never given. The two notices protect different things: the early warning protects the value of the event; the notification protects its existence.

For the fuller contrast between NEC's speak-up philosophy and FIDIC's protect-your-position regime, see our comparison of the FIDIC notice and the NEC4 early warning.

Do courts actually enforce NEC time bars?

Where they have been tested, yes. In Sitol Ltd v Finegold [2018] EWHC 3969 (TCC), the Technology and Construction Court enforced the NEC3 Short Contract's four-week time bar for referring disputes to adjudication — Sitol notified too late and lost the right to enforce an adjudication award for work it had done. As CMS note in their review of the case, the court applied the bar robustly, held that "awareness" of a dispute is judged objectively, and the judge applied it despite having "no great enthusiasm" for the point (CMS). The case is about a different NEC time bar, but the message for clause 61.3 is direct: NEC time limits are drafted to bite, and tribunals treat them as meaning what they say.

Readers familiar with FIDIC will recognise the pattern from Clause 20.1 and its 28-day time bar, which courts have likewise enforced as a condition precedent.

How entitlement actually leaks away

Across projects, the same failure modes repeat:

1. The event was never recognised as an event. A late access date or a drip of late information is lived with as "just how this job is" until the eight weeks are gone.
2. The early warning was treated as the notification. The matter was raised, minuted, even actioned — but no clause 61.3 notification was ever served, and raising it is not notifying it.
3. The clock was dated from recognition, not awareness. The team counted eight weeks from when the QS said "that's a compensation event", not from when the site team knew the event had happened.
4. The follow-up clocks were dropped. The notification went in; the one-week reply never came; nobody sent the reminder that triggers deemed acceptance, and the event drifted unresolved into the account.
5. The amended period was never read. The team ran an eight-week mental clock on a contract amended to four weeks — or one.

Each of these is an information failure, not a competence failure. The knowledge existed on the project; it just never reached the person who could serve the notice while the notice still mattered. It is the same chain we trace in how a programme slip becomes a contractual notice.

Where a governed AI layer helps

A contract-aware system that has read your particular NEC4 conditions — including the amendments — knows whether your notification period is eight weeks, four, or one. It can watch the live project record for events that look like clause 60.1 triggers, flag the awareness date honestly, remind the right person of the clause 15.1 early warning as well as the clause 61.3 notification, and track the one-week reply and reminder clocks after the notice goes in. The human still decides whether and what to notify, and every flag carries its citation back to the clause. The machine's job is narrower and duller: make sure no clock expires unseen.

This is general guidance on NEC4 procedure, not legal advice. Amended forms and governing law change how these clauses operate — the sources below are cited so you can verify, and you should take advice on your own contract.

Sources & further reading

• NEC Contracts (Steve Goodwin, GVE Commercial Solutions) — Notifying compensation events and time bars: a fairer approach needed. NEC's own platform on the eight-week bar (seven for subcontracts), which clause 60.1 events it can catch, and the fairness debate: https://www.neccontract.com/news/notifying-compensation-events-and-time-bars-a-fairer-approach-needed
• Brodies LLP (Stephanie Clarke) — What should a Contractor do when it becomes aware of an event that is the Client's liability under NEC4? The notification timetable: eight weeks, the one-week reply, the reminder and deemed acceptance, and amendments cutting the period to as little as one week: https://brodies.com/insights/construction-and-engineering/what-should-a-contractor-do-when-it-becomes-aware-that-an-event-has-occurred-which-is-the-clients-liability-under-the-nec4-contract/
• Arbicon (via PBC Today) — The NEC4 ECC Contract: Notifying Compensation Events and Early Warnings. The clause 61.3 wording, the 15.1 early warning, and the 61.5 / 63.7 assessment sanction with a worked Disallowed Cost example: https://www.pbctoday.co.uk/news/planning-construction-news/the-nec-4-ecc-contract-notifying-compensation-events-and-early-warnings/118114/
• Fenwick Elliott — NEC4: A Dispute Resolution Perspective. The NEC3-to-NEC4 wording change in clause 61.3 and the open question of when awareness arises: https://www.fenwickelliott.com/research-insight/newsletters/insight/75
• CMS — TCC applies NEC adjudication time-bar. Sitol Ltd v Finegold [2018] EWHC 3969 (TCC): the first court decision applying an NEC time bar, enforced strictly with awareness judged objectively: https://cms.law/en/gbr/legal-updates/TCC-applies-NEC-adjudication-time-bar