What qualifies
Each contract lists the events that entitle the contractor to more time: Relevant Events under JCT (for example variations, late information, employer’s impediment, exceptionally adverse weather, and under JCT 2024 discovery of asbestos or unexploded ordnance) and compensation events under NEC4. Contractor risk events, such as its own poor productivity, don’t qualify. Read the contract administration guide.
Step by step
- Notify promptly. JCT requires notice when it becomes reasonably apparent that progress is or is likely to be delayed. Under NEC4 the contractor must notify a compensation event within 8 weeks of becoming aware of it or, in most cases, lose the entitlement.
- Give particulars: the cause, the expected effect on completion, and supporting evidence.
- Show the critical path: use the programme to demonstrate that the event delays completion, not just an activity.
- Update as the delay develops.
- Claim the money separately: loss and expense (JCT) or the cost element of the compensation event (NEC).
Use our example delay notice.
Concurrent delay
Where a client delay and a contractor delay overlap, unamended JCT wording has been read as entitling the contractor to an extension (Walter Lilly v Mackay), though not necessarily to money. Parties can agree otherwise: in North Midland Building v Cyden Homes a clause excluding concurrent delay from EOT assessments was upheld. Check your amendments. More in our case studies.
If the EOT is refused
Ask for reasons in writing, provide further evidence and, if needed, refer the dispute to adjudication. If the client deducts liquidated damages meanwhile, check that it served any notices the contract requires.
General information, not legal advice. What applies to you depends on your contract, the facts and where the work is, and the law changes. Check the sources below and take advice from a qualified professional before acting on anything that matters.
Last updated: 10 October 2026
