Most commercial teams on NEC4 projects track one deadline: the eight-week time bar on compensation event notifications. That is one of more than 30 time obligations in the NEC4 Engineering and Construction Contract. The others are scattered across the core clauses, the main options, and Contract Data — and missing any of them has consequences. As Glenn Hide of GMH Planning noted in CECA Bulletin 34 on NEC4 contract timescales, there is a wide range of response periods across the contract that practitioners routinely overlook.
Some missed deadlines cost the Contractor entitlement permanently. Others mean the PM has accepted a quotation by default, whether they intended to or not. A few simply amount to a breach of contract with no mechanism to enforce the consequence. Knowing which is which is as commercially important as knowing the deadlines themselves.
This reference guide maps every key NEC4 response period, identifies which ones trigger automatic consequences, and explains how the compensation event response chain works in practice.
The Two Types of Response Period
NEC4 response periods fall into two distinct categories, and confusing them is one of the most common commercial errors on NEC4 projects.
Fixed periods written into the contract clauses. These are the same on every NEC4 ECC project regardless of what the parties agree in Contract Data. The most commercially significant are in the compensation event procedures: the eight-week notification window (clause 61.3), the one-week PM response to a CE notification (clause 61.4), the three-week quotation period (clause 62.3), and the two-week PM response to a quotation (clause 62.6). The PM's two-week acceptance window for a programme submission (clause 31.3) also falls in this category. These periods cannot be varied by Contract Data.
Contract Data periods. Set by the parties when the contract is executed. The most important is the period for reply under clause 13.3, which applies to all communications that do not have their own specific clause period. Design submissions, subcontracting approvals, requests for information, and most other routine communications are governed by the period for reply. Also in Contract Data: the programme submission interval, the defect correction period, and the payment assessment interval. These vary project to project — a period for reply of two weeks on one contract might be three weeks on another.
Why this distinction matters
If you believe a communication is governed by the period for reply but it actually has its own fixed clause period — or vice versa — your deadline tracking will be wrong. Always identify which category applies before calculating when a response is due. The CE response chain (clauses 61–62) operates entirely on fixed periods that override the period for reply.
Complete NEC4 Response Periods Reference
The table below covers the key time obligations across the NEC4 ECC, grouped by subject area. Contract Data entries are flagged — check your specific contract for those values.
| Activity | Who Acts | Period | Clause | If Missed |
|---|---|---|---|---|
| Compensation Event Process — fixed periods in the contract | ||||
| CE notification | Contractor | 8 weeks from awareness | 61.3 | Entitlement to price and time change permanently lost |
| PM response to CE notification | PM | 1 week | 61.4 | Notification treated as accepted |
| CE quotation submission | Contractor | 3 weeks from PM instruction | 62.3 | PM may make own assessment under clause 64 |
| PM response to CE quotation | PM | 2 weeks from last quotation submitted | 62.6 | Quotation may be deemed accepted (Contractor must notify) |
| PM response to revised CE quotation | PM | 2 weeks from revised quotation | 62.6 | Revised quotation may be deemed accepted |
| Programme — PM acceptance is a fixed period; submission intervals are in Contract Data | ||||
| Initial programme submission | Contractor | Period stated in Contract Data | 31.1 | PM may assess CEs without reference to a programme |
| PM acceptance or rejection of programme | PM | 2 weeks from submission | 31.3 | Breach; no automatic deemed acceptance |
| Revised programme submission | Contractor | At intervals stated in Contract Data | 32.2 | PM may assess CEs without the revised programme |
| Contract Data periods — check your specific contract | ||||
| General communication reply | PM or Contractor | Period for reply (Contract Data) | 13.3 | Breach; follow-up communication required |
| Design submission acceptance | PM | Period for reply (Contract Data) | 21.2 | Breach; Contractor should re-notify |
| Subcontracting approval | PM | Period for reply (Contract Data) | 26.3 | Breach; Contractor should re-notify |
| Defect correction | Contractor | Defect correction period (Contract Data) | 43.2 | PM may arrange correction; cost charged to Contractor |
| Payment | ||||
| Payment assessment | PM | Assessment interval (Contract Data, typically 4 weeks) | 50.1 | Breach |
| Payment to Contractor | Client | 21 days from assessment date (with Option Y(UK)2) | Y2.2 | Interest accrues on the amount due |
| Dispute Resolution (Option W2 — applicable to most UK contracts) | ||||
| Adjudicator decision | Adjudicator | 28 days from referral (extendable by agreement) | W2.3 | Decision may proceed by default; interest on disputed sums |
UK construction contracts subject to the Housing Grants, Construction and Regeneration Act 1996 have statutory minimum payment periods that apply alongside the above. Option Y(UK)2 is typically included in UK NEC4 contracts to ensure compliance. Beyond the CE process, other fixed periods include the three-week acceleration quotation window (clause 36), within which the Contractor must submit a quotation when the PM proposes acceleration to improve on the Completion Date.
The Compensation Event Response Chain
The four compensation event deadlines in the table above form a sequential chain. Each stage depends on the previous one completing, and the clock on each new stage starts when the previous stage is complete — not when the event first occurred. Understanding the chain as a single, connected timeline prevents commercial teams from treating each deadline in isolation.
The NEC4 CE response chain: four sequential deadlines from notification to PM assessment response
Scroll to see full diagram
Stage 1: Notification (clause 61). The Contractor notifies under clause 61.3 within eight weeks of becoming aware the event occurred. Where the event was caused by a PM or Supervisor action — an instruction, notification, certificate, or changed decision — the PM notifies under clause 61.1 and the Contractor eight-week time bar does not apply. The PM then has one week under clause 61.4 to accept the notification and instruct quotations, reject it with stated reasons, or confirm it was already notified.
Stage 2: Quotation (clause 62). Once the PM instructs quotations, the Contractor has three weeks to submit under clause 62.3. The quotation must cover the change to the Prices and any change to the Completion Date or Key Dates, including a revised programme if the CE affects planned Completion. Submitting a quotation without the time element — or without a revised programme when one is needed — gives the PM grounds to instruct a revised quotation, restarting the clock.
Stage 3: Assessment (clause 62). The PM has two weeks from the Contractor's last submitted quotation to respond. The PM may accept the quotation, instruct a revised quotation, or make their own assessment under clause 64. If the PM does not reply within two weeks, the Contractor may notify the PM that the quotation is treated as accepted. The Contractor must actively issue this notification — deemed acceptance is not triggered automatically by the passage of time. Once the Contractor issues the notification, the quotation is accepted and the change to the Prices, Completion Date, and Key Dates is final.
Deemed Acceptance: When Silence Becomes Consent
NEC4 contains specific provisions that treat a party's failure to respond as agreement to the other party's position. These are not general principles — they apply only where the contract explicitly creates the deeming mechanism. There are two in the CE process.
| Situation | Deemed Outcome | Clause | Automatic? |
|---|---|---|---|
| PM does not respond to CE notification within one week | Notification treated as accepted | 61.4 | Yes — no further action needed |
| PM does not respond to CE quotation within two weeks | Quotation treated as accepted | 62.6 | No — Contractor must notify the PM |
| PM does not respond to revised CE quotation within two weeks | Revised quotation treated as accepted | 62.6 | No — Contractor must notify the PM |
The asymmetry in the “Automatic?” column matters. A PM who misses the one-week CE notification response window has nothing to fall back on — the notification is accepted from that point, regardless of whether either party notices. A PM who misses the two-week quotation response window is only bound if the Contractor actively issues a clause 62.6 notification. Contractors who do not track PM response deadlines routinely miss this commercial advantage.
For programme submissions (clause 31.3), there is no equivalent deemed acceptance. The PM must accept or notify reasons within two weeks, and failure to do so is a breach of contract — but the programme is not automatically accepted. The Contractor's practical remedy is to raise the failure through the contract's communication and, ultimately, dispute resolution procedures.
Programme, Design, and Payment Periods
Programme
The initial programme must be submitted within the period stated in Contract Data Part 1 (typically four weeks after the Contract Date). Each subsequent programme revision is submitted at the intervals stated in Contract Data, or whenever the PM instructs. The commercial significance of the programme deadline is often underestimated: without an Accepted Programme, the PM assesses compensation events on their own assumptions about the planned sequence, which almost always disadvantages the Contractor. Keeping the programme accepted and current is as much a commercial discipline as it is a planning one. See the programme management guide for detail on Accepted Programme requirements and the NEC4 records and compliance guide for how good site records support programme and CE evidence.
Design and Subcontracting
Design submissions under clause 21.2 and subcontracting approvals under clause 26.3 both use the period for reply from Contract Data. If the PM misses these deadlines, the Contractor cannot unilaterally proceed on the basis of silence — there is no deemed acceptance mechanism for these activities. Re-notify using the contract's communication procedures and document the delay, which may itself constitute a compensation event under clause 60.1(6) (PM not replying within the period for reply) or clause 60.1(9) (PM withholding acceptance without reason).
Payment
The PM assesses the amount due at each assessment date, with the interval set in Contract Data (typically every four weeks). Under Option Y(UK)2, the due date for payment is one week after the assessment date, with the final date for payment 14 days after the due date — a maximum of 21 days from assessment. Late payment attracts interest under clause 51.3 at the rate stated in Contract Data. UK contracts subject to the Housing Grants, Construction and Regeneration Act 1996 operate with Option Y(UK)2, which sets out payment notices, pay-less notices, and the right to suspend for non-payment alongside the NEC4 payment clauses.
Worked Example: Access Delay and a Missed Quotation Deadline
A contractor is delivering a highway improvement scheme under NEC4 ECC Option C. The contract requires the Client to provide access to a key section of the works on 3 March. The access area is still occupied on that date.
Worked ExampleThe site manager records in the site diary that access has not been provided to Section 4. The commercial team identifies this as a compensation event under clause 60.1(2): the Client has not provided access on the date shown on the Accepted Programme. The Contractor notifies the CE under clause 61.3. The PM's one-week response clock starts.
The PM has not responded to the CE notification. The one-week period under clause 61.4 has expired. The notification is treated as accepted. The PM can no longer reject the notification on the basis that the event is not a compensation event.
The PM responds (one day late) and instructs the Contractor to submit quotations. The notification is already deemed accepted, so the PM's instruction to submit quotations proceeds. The Contractor's three-week quotation clock starts from the PM's instruction.
The Contractor submits a quotation for the access delay.
| Element | Defined Cost |
|---|---|
| Extended site establishment (2 weeks) | £38,000 |
| Additional plant and labour on standby | £44,000 |
| Programme revision (replanning affected works) | £9,000 |
| Defined Cost subtotal | £91,000 |
| Fee (8%) | £7,280 |
| Total change to Prices | £98,280 |
The quotation also proposes a two-week extension to the Completion Date, supported by a revised programme showing the access delay on the critical path.
The PM's two-week response window expires. The PM has not replied. The Contractor's commercial team identifies this using their deadline tracking and immediately issues a clause 62.6 notification: as the PM has not replied, the quotation of £98,280 plus two-week extension is treated as accepted.
The PM contacts the Contractor disputing elements of the cost build. The Contractor's commercial manager refers the PM to the clause 62.6 notification issued the previous day. The quotation is accepted. Any further dispute requires adjudication. Had the Contractor not tracked the PM's two-week deadline, they would almost certainly have accepted the PM's comments, revised the quotation downward, and lost significant commercial ground.
Gather tracks PM response deadlines automatically alongside Contractor notification deadlines. When the PM's two-week quotation response window is approaching expiry, the commercial team is alerted before it closes — so the clause 62.6 notification can be issued at the right moment, not missed entirely.
Five Common Mistakes with NEC4 Response Periods
1. Only tracking Contractor deadlines. The eight-week time bar receives most attention because missing it destroys entitlement. But the PM has its own response deadlines with their own consequences. Teams that track only Contractor obligations miss the commercial value of PM deadline failures. The deemed acceptance provisions in clauses 61.4 and 62.6 exist specifically to be used.
2. Treating the period for reply as a fixed contract term. The period for reply is a Contract Data entry. On projects where it has been set to three or four weeks rather than the standard two, significant time passes before a response is overdue. Always check Contract Data Part 1 at the start of the project, not when you think a deadline has been missed.
3. Assuming the PM's non-response means rejection. Under clause 61.4, the PM's silence on a CE notification within one week means the notification is accepted — the opposite of rejection. Treating silence as a cue to drop the CE and move on is commercially damaging. Document the notification, note the PM's failure to respond, and proceed with the quotation.
4. Confusing the quotation window with the response window. The Contractor has three weeks to submit the quotation. The PM then has two weeks to respond. These are sequential, not concurrent. The PM's two weeks starts from the Contractor's submission date. Calculating the PM deadline from the PM's original instruction (rather than the quotation submission date) leads to an incorrect — and earlier — deadline in the commercial team's records.
5. Not extending periods before they expire. Where a compensation event is complex and more time is genuinely needed, the PM and Contractor may agree different periods for the quotation and assessment stages. The agreement must be reached before the original period expires. After the period has passed, there is no mechanism for retrospective extension, and the deeming provisions may already have been triggered.
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