Contracts
Extension of time: what you must prove and by when
The short answer
An extension of time moves the contractual completion date to account for delay the contractor is not responsible for. Its main effect is to stop [liquidated damages](/blog/liquidated-damages-construction) running against the original date. It does not automatically bring money with it: loss and expense is a separate claim with its own tests. To succeed you must show a relevant event under the contract, a causal link to critical delay on the programme, and compliance with the notice provisions. Under NEC in particular, missing the notification period can defeat an otherwise good claim entirely.
At a glance
- Effect
- Moves the completion date
- Main benefit
- Stops liquidated damages
- Does not include
- Money; loss and expense is separate
- Must show
- Relevant event, critical delay, notice given
- JCT notice
- Forthwith when delay becomes apparent
- NEC notice
- 8 weeks from awareness, or the claim is lost
- Concurrent delay
- Time often granted, money often not
- Evidence
- A programme, updated, with records against it
What counts as a relevant event?
The contract lists them. They fall into three groups, and the group decides whether money follows the time.
| Group | Examples | Time? | Money? |
|---|---|---|---|
| Employer risk | Variations, late information, late access, employer’s own delay | Yes | Usually yes |
| Neutral | Exceptionally adverse weather, statutory undertakers, force majeure | Yes | Usually no |
| Contractor risk | Subcontractor failure, labour shortage, own resequencing | No | No |
The neutral group is the one that surprises people. Exceptional weather usually earns time but not money: the contractor is relieved of damages and carries its own prolongation cost. That is the bargain the standard forms strike.
Why does the notice deadline matter so much?
Because on some contracts it is a condition precedent. Under NEC4, a compensation event must be notified within eight weeks of the contractor becoming aware of it, and if it is not, the contractor loses entitlement to time and money both, however strong the underlying case.
JCT is less severe. It requires notice forthwith when it becomes reasonably apparent that progress is being delayed, and failure to give it generally weakens rather than destroys the claim. Even so, a late notice invites the argument that the employer was prejudiced and could have mitigated.
Notify early and notify in writing, even when the effect is not yet known. A notice that says "we do not yet know the delay" preserves the claim; silence does not.
What does a claim actually have to show?
- 01A relevant event. Identified by clause number, not described loosely.
- 02The date it began and became apparent. Which starts the notice clock.
- 03Its effect on the critical path. Delay to non-critical work delays nothing overall and earns no extension.
- 04A programme to measure against. Ideally the accepted baseline, updated as the work went.
- 05Contemporaneous records. Site diaries, labour returns, delivery notes, photographs, correspondence.
- 06The extension sought. In days, with the calculation shown.
Point three defeats more claims than any other. Work can be four weeks late and cost nothing in time if it had four weeks of float. Without a programme showing the critical path, the causal link cannot be demonstrated at all.
What about concurrent delay?
Concurrent delay is where two causes operate at the same time, one at the employer’s risk and one at the contractor’s, and either alone would have delayed completion.
The general English position is that the contractor gets time but not money. Time, because the employer cannot insist on a date it also prevented. No money, because the contractor would have incurred the prolongation cost regardless through its own delay.
NoteSome contracts now include express clauses that deny even time in a concurrency, and they have been upheld. Read the clause rather than relying on the general position.
How does loss and expense differ?
Extension of time deals with the date. Loss and expense deals with the cost of the delay, and it is claimed under a separate clause with separate notice requirements and a separate test.
Being granted an extension does not entitle you to money, and being refused one does not prevent a loss and expense claim if the head of loss stands on its own. In practice most prolongation cost is time-related preliminaries: supervision, accommodation, plant hire, insurance, each priced weekly.
Two claims, two clauses, two sets of notices. A submission that mixes them tends to be refused as a whole rather than assessed in parts.
Questions
Frequently asked
Does an extension of time mean I get paid more?
No. It moves the completion date and stops liquidated damages. Money for the extended period is a separate loss and expense claim with its own notices and its own test.
What is exceptionally adverse weather?
Weather beyond what could reasonably have been anticipated for that place and time of year, usually assessed against Met Office records for the location. Ordinary British winter rain is not exceptional.
Can I claim an extension after the completion date has passed?
Yes under most forms, and JCT expressly contemplates a review after completion. Notice should still have been given at the time, and a claim first raised months later will be met with an argument about prejudice.
What happens if the employer never responds to my claim?
Most contracts set a period for assessment, and failure to assess can itself be a breach. In serious cases, employer delay in a mechanism the employer controls can put time at large and remove the right to damages entirely.
Do I need a programme to claim an extension?
In practice yes. Without one there is no way to show the delay hit the critical path, and demonstrating that is the whole of the causation argument.
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