When a construction project falls behind programme, showing that a delay occurred is not enough. A contractor seeking an extension of time must usually demonstrate what caused the delay, when it occurred and how it affected the contractual completion date.

This is why records are so important. A successful extension of time claim requires a clear connection between the event causing the delay, its actual effect on the critical path and the resulting impact on the completion date.

This guide explains extension of time claims: what records do you need to prove delay, including programme updates, site diaries, progress reports, notices, photographs and other project records that can help establish entitlement.

What is an extension of time?

An extension of time, often shortened to EOT, is a contractual mechanism that allows the completion date to be adjusted where qualifying delay events occur.

Construction contracts generally specify which events may give rise to an extension of time and what the contractor must do to claim one. If entitlement is established, the contract completion date can be moved to reflect the period of critical delay caused by the qualifying event.

An extension of time does not automatically mean the contractor is entitled to financial compensation. Time and money are often dealt with separately under construction contracts.

What must an extension of time claim prove?

A strong EOT claim should normally establish three things:

• Entitlement: the delay arose from a relevant contractual event.
• Causation: the event actually delayed the works.
• Critical impact: the delay affected the critical path and pushed out the completion date.

This distinction matters. A delay event can occur without affecting completion. If an activity has sufficient float, for example, the event may cause disruption without creating a critical delay.

Critical delays affect the project's completion date. Non-critical delays do not. Extension of time claims therefore need evidence that connects the relevant event to activities controlling completion.

Start with the contract

Before assessing any delay claim, check the contract provisions.

Standard form contracts such as JCT contracts and the New Engineering Contract use different terminology and procedures. The relevant parties therefore need to understand the particular contractual requirements that apply.

Check:

• The original completion date
• The contract particulars
• Which delay events can give rise to additional time
• Notice requirements
• Any condition precedent or time bar
• The procedure for assessing extensions
• The requirements for programme information.

Missing a notice requirement can significantly weaken an otherwise valid delay claim.

JCT extension of time claims

Under JCT contracts, the contractor will typically need to notify delay and identify the relevant events relied upon.

Relevant events may include variations, delayed possession, certain employer instructions and exceptionally adverse weather conditions, depending on the form and amendments being used.

The contract administrator assesses whether the event affected completion and what extension of time, if any, should be granted.

A JCT extension of time certificate moves the completion date. That is important because liquidated damages are generally assessed against the revised completion date rather than the original date.

Relevant matters are separate and may establish a contractual entitlement to loss and expense or other financial compensation in certain circumstances.

NEC compensation events and delay

Under NEC contracts, delay is commonly dealt with through the compensation event procedure.

The project manager and contractor assess the effect of compensation events against the accepted programme. Programme management therefore becomes particularly important when claiming extensions of time under an NEC engineering contract.

An eight-week notification time bar can apply to contractor-notified compensation events under the NEC, subject to the specific contract provisions and applicable exceptions. Contractors should therefore avoid leaving notifications until the full effect of a delay is known.

The baseline programme

The baseline project programme is one of the most important records in any EOT claim.

It establishes how the contractor originally intended to complete the construction work and identifies the logic linking activities to the completion date.

A useful baseline should show:

• Activity durations
• Logic links
• Key milestones
• Critical path activities
• The planned completion date.

Without a reliable programme, demonstrating the programme impact of a delay event becomes considerably harder.

Programme updates

The baseline alone is not sufficient. Regular programme updates show how the project actually developed over time.

Updated programmes can identify when a delay occurs, changes to the critical path and whether mitigation measures or resequencing recovered lost time.

A well-prepared EOT claim should use programme updates to establish the position immediately before, during and after the event causing delay.

Where the delay claim becomes contentious, specialist planning and delay analysis can help compare actual progress against planned progress and assess the impact of specific delay events.

Site diaries and daily records

Site diaries provide some of the most useful contemporaneous evidence in extension of time claims.

Good site diaries should record:

• Workforce numbers
• Activities taking place
• Plant and equipment
• Weather conditions
• Areas unavailable for work
• Late information or instructions
• Interruptions and delays.

Daily records help establish what was really happening when the delay occurred rather than relying on recollections months later.

Progress reports and photographs

Progress reports provide another important evidence trail.

They can show completion rates, programme concerns, access problems, design issues and mitigation measures being considered by the project team.

Progress photographs are particularly useful when they are dated and clearly linked to locations and activities. Time-stamped photographs may help demonstrate incomplete preceding work, restricted access or the physical status of an affected activity.

Photographs are strongest when supported by other detailed records rather than used in isolation.

Meeting minutes and correspondence

Meeting minutes can provide contemporaneous evidence that an issue was recognised at the time.

For example, site coordination meeting minutes may record:

• Late design information
• Employer delays
• Outstanding instructions
• Material shortages
• Programme concerns
• Agreed mitigation measures.

Emails and formal letters can also establish when information was requested, when instructions were issued and when relevant parties became aware of an event.

However, records should show more than simply that a problem existed. They should help establish a clear link between the delay event and its impact on the project programme.

Weather and unforeseen site conditions

Adverse weather is a common source of construction delay, but saying that conditions were unusually bad will rarely be sufficient on its own.

Official meteorological data can help substantiate claims involving adverse weather conditions. Site diaries should also record weather and its actual effect on construction work.

Similarly, unforeseen site conditions should be documented through photographs, surveys, instructions, correspondence and programme records.

The question remains the same: what was the actual effect on the critical path and completion date?

How delay analysis proves causation

Delay analysis connects the evidence to the programme.

A critical path analysis can help determine whether the event caused critical delay, when that delay arose and how long it affected completion.

Records should support the analysis rather than conflict with it. If an updated programme indicates an activity was progressing normally, while the EOT claim later states it had already been critically delayed, that inconsistency may undermine the claim.

The Society of Construction Law's Delay and Disruption Protocol provides widely used guidance on extensions of time, delay analysis and disruption.

What about concurrent delay?

Concurrent delay can arise where employer delays and contractor delays overlap.

This can complicate assessing an extension of time, as the analysis must establish the effect of each event on the critical path.

Detailed records and programme updates are particularly important where two delay events may have operated during the same period.

Can a contractor recover additional costs?

An extension of time protects the contractor against liability for delay for the relevant period, but additional payment is a separate issue.

Prolongation costs or other additional costs generally need their own contractual basis and evidence. A quantity surveyor assessing applications will need records showing the financial consequences and a clear connection between the employer risk event and the additional expenditure claimed.

Cost ledgers and impact logs, site records, payroll information, plant records and invoices may all provide relevant information.

Common mistakes in extension of time claims

Common mistakes include:

• Failing to issue notices within the contract requirements
• Relying on an outdated project programme
• Showing that an event happened but not proving critical path impact
• Poor record keeping
• Failing to separate critical and non-critical delay
• Claiming the full period of an event without demonstrating its actual effect
• Failing to document mitigation measures
• Mixing entitlement to time with entitlement to financial compensation.

These issues are easier to address while a construction project is live. Novus Resolve's dispute avoidance work focuses on identifying and managing problems before positions become entrenched.

How can a contractor recover delay?

Where delay occurs, the priority should be to understand the cause and assess whether mitigation is possible.

Recovery measures might include resequencing activities, reallocating labour, changing working methods or increasing resources where commercially and practically justified.

Mitigation does not remove the need to keep detailed records. The contractor should record both the original delay and the steps taken to recover it.

Can an extension of time be claimed after practical completion?

Potentially, yes. Whether an EOT claim can be submitted or assessed after practical completion depends on the construction contract, its notice provisions and the circumstances.

Some standard forms allow the completion date to be reviewed after practical completion. However, contractors should never assume they can wait until the end of the project. Notice provisions and any condition precedent should be followed when the relevant event occurs.

What is a good reason for an extension of contract time?

A good reason is not simply that the project took longer than expected. There must normally be a qualifying event recognised by the contract that caused delay to completion.

Examples may include employer-caused delay, qualifying variations, certain weather conditions, late access or other relevant events or compensation events identified by the particular contract.

Conclusion

Successful extension of time claims depend on evidence.

The contractor needs to establish entitlement under the contract, prove the event causing delay and demonstrate its actual effect on the critical path and completion date.

The most useful records include the baseline programme, updated programmes, site diaries, progress reports, meeting minutes, correspondence, photographs and formal notices.

Good record keeping throughout construction projects makes delay analysis more reliable and gives the contractor a much stronger basis for establishing contractual entitlement.

Contact Novus Resolve

At Novus Resolve, we provide expert planning and delay analysis to help contractors, employers and professional teams understand why delays occurred and how they affected completion.

From programme reviews and critical path analysis to forensic delay analysis and support with extension of time claims, we provide evidence-based analysis designed to clarify complex delay issues.

Contact Novus Resolve to discuss an extension of time or construction delay claim.