How to Prepare an Extension of Time Claim in Denmark (AB 18): Notices, Deadlines & Evidence

Understanding how to prepare an extension of time claim is one of the most commercially important skills for any contractor or project counsel operating on Danish construction projects in 2026. Under the widely used AB 18 and ABT 18 standard-form conditions, the contractor’s right to additional time hinges on prompt notice, rigorous evidence assembly, and a clearly structured submission that links cause to effect. With Danish arbitration tribunals increasingly scrutinising whether notices were given “as soon as possible,” a late or incomplete claim can forfeit an otherwise legitimate entitlement, turning an employer-caused delay into a costly liability for the contractor.

Quick Answer: Can I Prepare an EOT Claim Under AB 18?

Yes. Under Denmark’s AB 18 general conditions for building and construction works, a contractor is entitled to request an extension of time when the completion date is delayed by events that are not attributable to the contractor. These include employer-caused delays (late design information, variations, failure to provide site access), force majeure events, and extraordinary weather conditions that exceed the statistical norms for the region and season.

An extension of time on a construction contract is a formal adjustment to the contractual completion date, recognising that the contractor should not bear liability (such as delay damages or liquidated damages) for delays outside its control. Crucially, the right to an extension of time under AB 18 is not self-executing, the contractor must give written notice as soon as possible after becoming aware of the delaying event. Industry observers expect that the practical meaning of “as soon as possible” requires the contractor to issue notice within days, not weeks, of identifying the delay trigger.

The immediate actions to preserve your claim are: (1) issue a preliminary written notice identifying the delaying event, (2) begin capturing contemporaneous evidence from the moment the event is identified, and (3) follow up with a detailed, substantiated EOT claim within a reasonable period.

AB 18 & ABT 18: Legal Framework and Key Notice Clauses

Where AB 18 Requires Notice, and Critical Timing Language

AB 18, published by the Danish collaboration body for general conditions in building and construction, is the standard-form contract governing most Danish building projects. Its time-extension provisions require the contractor to notify the employer of any circumstances that may cause delay “as soon as possible.” This language is deliberately open-ended: AB 18 does not specify a fixed number of calendar days. The practical interpretation, however, has been tightened over successive rounds of Danish arbitration practice, the likely practical effect in 2026 is that contractors should treat the notice window as seven to fourteen calendar days from the date the delaying event is first identified or reasonably should have been identified.

ABT 18 Differences

ABT 18 applies to turnkey (design-and-build) contracts in Denmark. While its notice and extension-of-time provisions mirror AB 18 in structure, the turnkey contractor bears broader design responsibility. This means that delays arising from the contractor’s own design process are generally not grounds for an AB 18 extension of time. However, where a turnkey contractor experiences delay caused by employer variations, late information, or force majeure, the ABT 18 time limits and notice obligations mirror AB 18, including the “as soon as possible” notice requirement.

Consequences of Late or No Notice

Failure to give timely notice under AB 18 can result in partial or total forfeiture of the extension of time entitlement. Danish Arbitration Board decisions have consistently held that the notice obligation is not a mere formality: it serves the employer’s legitimate interest in being informed early enough to take mitigating action (for example, re-sequencing work, engaging additional resources, or adjusting downstream procurement).

If a contractor fails to notify the employer and later submits a retrospective EOT claim, the arbitration tribunal will assess whether the employer was prejudiced by the late notice. In many cases, prejudice is presumed from the passage of time alone. The bottom line: a technically correct claim submitted months after the delaying event is far weaker than a promptly notified claim, even if the underlying entitlement is clear.

Practical takeaway: Draft a standing internal procedure requiring site managers to flag potential delay events within 48 hours, so project counsel can issue formal notice well within the pragmatic 7–14-day window.

Step-by-Step: How to Prepare an Extension of Time Claim

Assembling a successful EOT claim in Denmark follows five core steps: preserve evidence immediately, issue contractual notice, collect and organise your evidence pack, conduct a delay analysis, and compile the final quantified submission. Each step builds on the last, skip one and the claim structure collapses.

Step 1: Immediate Actions on Identifying a Delaying Event

The moment a delaying event is identified on site, the contractor should take three preservation actions simultaneously:

• Issue a preliminary notice. Even a brief written communication (email or letter) that identifies the event, its potential effect on the programme, and a statement that a detailed claim will follow satisfies the initial “as soon as possible” AB 18 obligation.
• Photograph and document. Capture timestamped photographs, video, and GPS-tagged records of the site conditions causing or evidencing the delay.
• Secure daily logs. Instruct the site manager to prepare detailed daily reports from the date the event begins, noting weather conditions, labour present, plant operational status, and activities affected.

Step 2: Contractual Notice, What to Include and Exact Wording

The formal delay notice Denmark construction practice requires should include the following minimum contents:

• Contractual basis. Reference the specific AB 18 clause entitling the contractor to an extension of time.
• Description of the event. A clear, factual narrative of what happened, when it started, and who or what caused it.
• Effect on the programme. Identify which activities on the critical path are affected and what the anticipated delay to completion is.
• Estimated duration. Provide a preliminary estimate of the time extension sought (this can be refined later in the detailed submission).
• Mitigation measures. Describe any steps the contractor is taking, or proposes to take, to mitigate the delay.
• Reservation of rights. State that the contractor reserves the right to claim additional time and associated costs as the full impact becomes known.

Template snippet, preliminary notice:

“We hereby give notice under AB 18 that [describe event] has occurred on [date], affecting activities [list critical activities]. Based on our preliminary assessment, the event is expected to cause a delay of approximately [X] working days to the contractual completion date. We are taking [describe mitigation measures] and reserve our right to submit a detailed extension of time claim and associated cost claim in due course.”

Step 3: Collecting Evidence

Evidence is the backbone of every successful EOT claim Denmark contractors submit. The goal is to build a contemporaneous, verifiable record linking the delaying event to its impact on completion. The following evidence pack checklist should be assembled as close to real time as possible:

Quick preservation checklist:

• Back up all digital site records to a secure, off-site location within 24 hours of the event.
• Instruct all supervisors to switch daily reports to “enhanced mode” (longer narratives, explicit reference to delay cause).
• Do not overwrite or update the baseline programme, create a separate snapshot labelled with the event date.
• Tag and index all photographs by date, location, and the delay event they relate to.

Step 4: Delay Analysis Methodology

A time extension construction contract claim must demonstrate the causal link between the delay event and the impact on the contractual completion date. This requires a recognised delay analysis methodology. The most commonly accepted approaches are:

• Time Impact Analysis (TIA). Inserts the delay event into the baseline or updated programme as a new activity, then measures the resulting shift in the completion date. TIA is the preferred method for prospective analysis (used before or shortly after the event) and is widely accepted by Danish arbitration tribunals.
• Windows analysis. Divides the project into sequential time windows and analyses delay in each window by comparing planned versus actual progress. This is particularly useful for complex, multi-event delay situations and is favoured for retrospective claims.
• As-built vs. baseline (collapsed as-built). Compares the original programme to the actual completion sequence and allocates responsibility for each period of delay. This is simpler but may be challenged where concurrent delays exist.

Early indications suggest that Danish tribunals in 2026 favour methodologies that use contemporaneous programme data over pure theoretical reconstructions. Choose the method that best fits your available data and the complexity of the delay events.

Step 5: Quantification and Submission Pack

The final EOT claim submission should be a self-contained document that enables the employer (or, ultimately, an arbitrator) to understand and assess the claim without requesting additional information. The submission pack should include:

• Executive summary. One to two pages covering the delay event, the extension requested, and the cost consequences.
• Narrative. A chronological, factual account of the delay event, cross-referenced to evidence appendices.
• Cause-and-effect analysis. The delay analysis demonstrating the link between the event and the programme impact (using the chosen methodology).
• Summary table. A single-page table listing each delay event, the AB 18 clause relied upon, the number of days requested, and the supporting appendix reference.
• Supporting documents. Indexed and tabbed appendices containing all evidence items from the checklist above.
• Claim for costs. If seeking prolongation or disruption costs in addition to time, include a separate cost section (see below).

Notices: Timing, Required Content, and Sample Notice Language

“As Soon as Possible” Explained for Extension of Time Denmark Claims

AB 18 uses the phrase “as soon as possible” (snarest muligt in Danish) without defining a fixed number of days. This deliberate flexibility means the obligation adapts to the circumstances, but it is never interpreted as permitting weeks of silence. In practice, industry observers expect Danish arbitrators to accept notice given within seven to fourteen calendar days as timely in most situations, provided there is no evidence that the contractor was aware of the event significantly earlier. Where the delaying event is sudden and obvious (for example, an employer instruction to stop work), notice should issue within days, not at the end of the following week.

Minimum Required Contents of a Delay Notice

A delay notice Denmark construction contracts require should contain, at minimum:

• The date of the notice and the identity of the issuing party.
• A reference to the applicable AB 18 or ABT 18 clause.
• A clear description of the delaying event and its date of occurrence.
• The anticipated effect on the completion date (even if only a preliminary estimate).
• A statement that a detailed claim will follow, and a reservation of the right to claim additional time and costs.

Omitting any of these elements does not automatically invalidate the notice, but an incomplete notice is far easier for the employer to challenge, and it weakens the contractor’s credibility before a tribunal.

Practical Templates: Preliminary Notice and Detailed EOT Notice

Template 1, Preliminary notice (issue within 7 days of the event):

“To: [Employer / Contract Administrator]
Re: Notice of delay, [Project name], Contract ref. [X]
Date: [Date]

Pursuant to AB 18, we notify you that [brief description of the delaying event] occurred on [date]. This event is affecting [critical path activities] and is expected to delay practical completion by approximately [X] working days. We are taking [mitigation steps] and will submit a detailed extension of time claim within [timeframe]. We reserve all rights to an extension of time and associated costs.”

Template 2, Detailed EOT claim cover letter (submit within 28–42 days of the event):

“To: [Employer / Contract Administrator]
Re: Extension of time claim No. [X], [Project name], Contract ref. [X]
Date: [Date]

Further to our preliminary notice dated [date], we enclose our detailed extension of time claim in respect of [delay event]. The enclosed submission comprises: (1) Executive summary; (2) Chronological narrative; (3) Time Impact Analysis; (4) Summary of extension sought: [X] calendar days; (5) Prolongation cost claim: €[amount]; (6) Supporting evidence (Appendices A–[X]). We request that you review and respond within [X] days in accordance with the contract.”

Delay Entitlement vs. Damages: Disruption vs Prolongation Costs

Definitions: Delay, Disruption, and Prolongation

These three concepts are frequently conflated but are legally distinct under Danish construction practice:

• Delay (time). An extension of time adjusts the contractual completion date. It relieves the contractor from liability for delay damages (liquidated damages) for the period of the extension. It is a time remedy, not a money remedy.
• Disruption (inefficiency). Disruption occurs when the contractor can still complete within the original timeframe (or the extended timeframe) but at greater cost due to loss of productivity, for example, out-of-sequence working, stacking of trades, or frequent stop-start patterns. Disruption costs compensate for the additional resources consumed to achieve the same output.
• Prolongation (extended presence). Prolongation is the additional cost the contractor incurs because the project duration has been extended through no fault of its own. These are time-related costs: site overheads, supervisory staff, extended plant hire, insurance, and temporary facilities that continue to accrue during the delay period.

When to Claim Prolongation Costs

A contractor who is granted an AB 18 extension of time may also be entitled to recover the disruption vs prolongation costs associated with the extended period, depending on the cause of the delay. As a general rule, prolongation costs are recoverable where the delay is caused by the employer (e.g., late information, variations, failure to provide access). Force majeure events typically entitle the contractor to additional time but not additional money, each party bears its own costs during force majeure delays.

Prolongation cost claims should cover:

• Site establishment costs (offices, welfare facilities, utilities) for the extended period.
• Supervisory and management staff who remain on site solely because of the delay.
• Idle plant or extended hire charges for equipment that cannot be redeployed.
• Insurance, bond, and guarantee costs for the extended project duration.
• Head-office overhead contribution (often calculated using recognised formulae).

Sample Prolongation Cost Calculation

The following illustrative example shows how prolongation costs might be quantified for a 30-calendar-day employer-caused extension. All figures are hypothetical and should be replaced with project-specific rates verified by a construction disputes specialist.

Practical takeaway: Always present prolongation and disruption as separate, clearly labelled heads of claim. Mixing the two weakens both.

Dispute Escalation and Danish Arbitration Practice

Typical Pathways: Contract Administration to Arbitration

Under AB 18, EOT disputes typically escalate through the following sequence:

1. Contract administration. The contractor submits the claim; the employer (or the contract administrator on behalf of the employer) reviews and either grants, partially grants, or rejects the extension.
2. Negotiation / mediation. If the claim is rejected or only partially granted, the parties may attempt to resolve the dispute through direct negotiation or mediation, although AB 18 does not mandate mediation as a prerequisite to arbitration.
3. Arbitration. AB 18 designates the Danish Arbitration Board for Construction and Civil Engineering (Voldgiftsnævnet for bygge- og anlægsvirksomhed) as the dispute resolution forum for construction disputes. Arbitration is binding.
4. Courts. Court proceedings are rare for AB 18 disputes, as the arbitration clause is typically treated as exclusive.

Danish Arbitration Board Deadlines and Evidence Expectations

The Danish Arbitration Board expects detailed, contemporaneous evidence. The standard of proof for an EOT claim in Denmark is a balance of probabilities, but weak or retrospective documentation dramatically reduces the contractor’s prospects. Key evidence expectations include properly maintained programme records, contemporaneous site diaries, and credible delay analysis conducted by a qualified planning professional.

Contractors should retain all project records for a minimum of five years after practical completion, and longer if any dispute or defects liability period extends beyond that point. Organise arbitration bundles chronologically, index every document, and ensure all evidence is cross-referenced to the narrative in the claim submission.

Red flags that kill EOT claims in arbitration:

• Notices sent months after the delaying event without a credible explanation for the delay.
• No baseline programme on file, or a baseline that was never accepted by the employer.
• Daily site reports that are generic, unsigned, or clearly prepared retrospectively.
• Delay analysis performed by someone without planning qualifications or using a non-recognised methodology.
• Prolongation costs calculated without supporting invoices, hire agreements, or payroll records.

Practical Toolkit and Downloads

To support contractors and project counsel in assembling a robust AB 18 extension of time claim, the following resources should form part of every project’s claims management toolkit:

• Evidence pack checklist (PDF). A printable version of the ten-item evidence table above, formatted for site use with tick boxes and notes columns.
• Preliminary notice template (Word). A ready-to-complete template aligned with the AB 18 notice requirements set out in this guide.
• Detailed EOT submission template (Word). A structured claim document template with pre-built sections for executive summary, narrative, delay analysis, cost claim, and appendix index.
• Prolongation cost calculator (Excel). A simple spreadsheet allowing the user to input daily or monthly rates for site overhead, staff, plant, and insurance, and calculate total prolongation costs for a specified delay period.

These templates should be adapted to the specific AB 18 or ABT 18 contract provisions on each project. Consult qualified Denmark construction lawyers before submitting any claim to ensure it complies with the notice and procedural requirements of the applicable contract.

Conclusion: How to Prepare an Extension of Time Claim, Recommended Immediate Steps

Knowing how to prepare an extension of time claim under AB 18 is not optional for contractors working on Danish construction projects, it is an essential discipline that protects contractual entitlements and avoids unnecessary exposure to liquidated damages. The difference between a successful claim and a forfeited one almost always comes down to the speed and quality of the initial notice and the rigour of the supporting evidence.

If a delaying event has occurred, or is about to, take these five steps immediately:

1. Issue a preliminary written notice under AB 18 within seven days of identifying the event.
2. Begin contemporaneous evidence capture (photos, daily reports, programme snapshots) on day one.
3. Engage a qualified delay analyst to select and apply the appropriate analysis methodology.
4. Prepare and submit the detailed EOT claim, with full evidence pack, within 28 to 42 days.
5. Seek advice from experienced Denmark construction counsel to review the claim before submission and advise on the extension of time Denmark-specific procedural requirements.

Sources

1. AB 18, NJORD Law English Summary
2. Danish Arbitration Board (Voldgiftsnævnet for bygge- og anlægsvirksomhed)
3. RICS, Extensions of Time Guidance
4. SmartPM Training, How to Write an EOT Claim
5. Designing Buildings Wiki, How to Prepare a Claim
6. ScienceDirect, Delay Analysis Methods