JCT Extension of Time: Notices, Relevant Events and How Contractors Protect Their Position

A JCT extension of time is a later Completion Date fixed under a JCT contract because the progress of the works has been delayed by a Relevant Event. It protects the contractor from liquidated damages for the period of the extension and keeps the Completion Date enforceable when the employer causes or carries the risk of delay.

Most contractors know an extension of time exists. Fewer manage the process well. Notices are sent late, particulars are thin, the programme cannot show the effect of the delay and the claim is argued months later from incomplete records. This guide explains how JCT extension of time works, what the 2024 editions changed and how a contractor can protect its position from the first sign of delay.

Clause numbers below refer to the JCT Design and Build Contract. The Standard Building Contract follows the same principles with different numbering, where the decision is made by the Architect or Contract Administrator rather than the Employer. Always check the edition and any amendments in your own contract.

How does extension of time work under JCT?

The JCT process has three stages.

1. Notice of delay

Under clause 2.24, if and whenever it becomes reasonably apparent that the progress of the works is being or is likely to be delayed, the contractor must forthwith give written notice of the material circumstances, including the cause or causes of the delay. The notice must identify any event which, in the contractor's opinion, is a Relevant Event.

The trigger is wide. It applies to any delay to progress, not only delay the contractor thinks is the employer's fault. It also applies when delay is likely, not only when it has happened.

2. Particulars and estimate

The contractor must then give particulars of the expected effects of each Relevant Event and an estimate of the extent of the expected delay to completion beyond the Completion Date. Where the position changes, the contractor must notify the change and update its particulars and estimate.

This is where most extension of time claims succeed or fail. A notice without particulars gives the decision maker nothing to assess.

3. The decision

Once it has the notice and particulars, the Employer decides whether any Relevant Event has delayed completion and, if so, fixes a later Completion Date that it considers fair and reasonable. The Employer must notify its decision within the period the contract allows.

After practical completion, the contract allows the Completion Date to be reviewed again, taking account of Relevant Events notified during the works.

Throughout, the contractor must constantly use its best endeavours to prevent delay and must do everything reasonably required to proceed with the works.

What changed in the JCT 2024 editions?

The JCT 2024 Design and Build Contract made several changes to extension of time:

The 2024 editions also allow notices to be served by email where the Contract Particulars provide for it. Many contracts are still let on the 2016 editions, so contractors should confirm which edition applies before relying on any time period.

What are the JCT Relevant Events?

Relevant Events are set out in clause 2.26. They are the events that entitle the contractor to more time. Under the Design and Build Contract they include:

• Changes and other instructions from the Employer
• Deferment of possession of the site
• Opening up and testing of work that is found to be in accordance with the contract
• Any impediment, prevention or default by the Employer or those it is responsible for
• Work by statutory undertakers carrying out their statutory obligations
• Exceptionally adverse weather conditions
• Loss or damage caused by any of the Specified Perils
• Civil commotion, terrorism and the threat of terrorism
• Strikes and similar actions affecting the trades or supply of goods
• The exercise of a statutory power affecting the works, which the 2024 edition extends to changes in law and published guidance
• Force majeure
• In the 2024 edition, epidemics and the discovery of asbestos, contaminated material and unexploded ordnance

Contract amendments frequently delete or narrow some of these, particularly weather, statutory undertakers and force majeure. Read the amended list, not the standard one.

Is JCT notice a condition precedent?

The standard JCT notice provisions are not generally treated as a condition precedent to an extension of time. A late notice does not normally remove the entitlement altogether.

That does not make late notice safe. Bespoke amendments often turn notice into a condition precedent with strict time limits. Even where they do not, a late or vague notice makes the delay harder to prove, gives the employer less opportunity to act and weakens the contractor's credibility when the claim is assessed.

What about concurrent delay?

Concurrent delay arises where a Relevant Event and a contractor risk event both delay completion over the same period.

Under unamended JCT terms, the courts have generally held that the contractor is entitled to an extension of time for the Relevant Event even where there is concurrent contractor delay. That was the approach taken in Walter Lilly & Company Ltd v Mackay [2012] EWHC 1773 (TCC), a case on an earlier JCT form. Loss and expense is a separate question and is not normally recoverable for a period of true concurrency.

Parties can agree a different position. In North Midland Building Ltd v Cyden Homes Ltd [2018] EWCA Civ 1744, the Court of Appeal upheld an amended JCT clause stating that concurrent delay would not be taken into account when assessing an extension of time. Contractors should check their contract for concurrency clauses before tender.

Extension of time versus loss and expense

An extension of time deals with time. Loss and expense deals with money. They are separate entitlements under separate provisions.

• Extension of time is based on Relevant Events and protects against liquidated damages
• Loss and expense is based on Relevant Matters and compensates the contractor for direct loss and expense caused by them

Some events give rise to both. Some, such as exceptionally adverse weather, normally give time but not money. Each entitlement needs its own notice and supporting information. Our quantity surveying support works alongside project management on the commercial side of delay.

How contractors protect their position on delay

The strongest extension of time claims are built during the project, not after it.

1. 1Keep the programme current. A baseline programme with logic links and regular progress updates is the foundation of any delay analysis. For NEC contracts the equivalent discipline is covered in our guide to the NEC4 Accepted Programme.
2. 2Notify early. Give notice as soon as delay is reasonably apparent or likely. Update it as the position develops.
3. 3Provide real particulars. Show the cause, the activities affected, the effect on the critical path and a reasoned estimate of delay.
4. 4Keep contemporaneous records. Daily diaries, instructions, correspondence, photographs, labour and plant records and progress reports are the evidence that proves cause and effect.
5. 5Separate time and money. Track Relevant Events and Relevant Matters together but notify and substantiate them separately.
6. 6Show mitigation. Record what was done to reduce the delay. The contract requires best endeavours to prevent delay and a decision maker will expect to see them.
7. 7Diarise decision periods. Track when a decision is due and follow up when it is not received.

Common JCT extension of time failings

• Notices sent only when liquidated damages are threatened
• Notices that describe a problem but do not identify a Relevant Event
• No particulars or estimate of delay
• Programmes that are not updated, so the effect of delay cannot be shown
• Time and money claims mixed into a single submission
• Concurrency ignored until the employer raises it
• Amended notice clauses not read until after the time limit has passed

Need support with JCT contract administration?

Matthews & Roberts supports contractors with JCT and NEC contract administration on live projects. That includes delay notices, particulars, programme updates and the records needed to support an extension of time, so completion dates stay credible and liquidated damages exposure is managed.

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