A construction delay claim is a formal submission seeking an extension of time (EOT) and/or additional costs arising from events that have delayed the progress of works beyond the contractual completion date. This guide covers everything from identifying delay events through to submitting a formal claim.
A delay claim is a contractor's formal request for relief — typically an extension of time and/or compensation for prolongation costs — arising from events that were not the contractor's responsibility and that have caused the works to be delayed beyond the contractual completion date.
The first and most critical step is issuing a timely notice of delay under the contract. Under FIDIC 2017, the contractor must give notice within 28 days of becoming aware of the event (Clause 20.2.1). Under NEC4, the deadline is 8 weeks (Clause 61.3). Under JCT, the requirement is to give notice "forthwith" or as soon as reasonably practicable.
Missing the contractual notice period can permanently bar your entitlement — this is known as a time bar or condition precedent. For a detailed walkthrough of drafting a compliant notice, see our dedicated guide.
A well-structured delay claim typically includes: (1) Executive Summary, (2) Project Background, (3) Contractual Basis, (4) Chronology of Delay Events, (5) Programme Impact Analysis, (6) Methodology, (7) Financial Impact, (8) Supporting Evidence, and (9) Relief Sought. Delay Claim Builder generates this structure automatically.
The five recognised delay analysis methodologies are: Time Impact Analysis (TIA), Windows Analysis, As-Planned vs As-Built, Impacted As-Planned, and Collapsed As-Built. The choice depends on available records, programme quality, and the complexity of the delay.
The SCL Protocol provides guidance on when each methodology is most appropriate. For detailed coverage of each method, see our individual articles.
Concurrent delay arises when two or more events — one employer risk, one contractor risk — affect the critical path simultaneously. Under English law (following City Inn v Shepherd Construction), the contractor may still be entitled to an EOT even with true concurrency, but costs are contested.
Common heads of prolongation cost include: site preliminaries, head office overhead (calculated via the Emden or Hudson formula), plant standing time, acceleration costs, and finance charges.
For a full breakdown of the 10 most common heads of prolongation cost and how to calculate them, see our dedicated guide.
The most common reasons delay claims fail include: late notice (missing the contractual notification deadline), insufficient contemporaneous records, failure to demonstrate critical path impact, mixing concurrent delays without proper analysis, and inadequate financial substantiation.
Evidence quality makes or breaks a claim. Ensure you have contemporaneous records across all 14 evidence categories before submission.
Claim rejections are common — and not the end. Many are issued on formulaic grounds that can be dismantled with a structured rebuttal addressing each rejection ground individually.
For complex, high-value claims involving multiple concurrent delays, a specialist delay analyst may be necessary. For the majority of claims, Delay Claim Builder produces submission-ready documents at a fraction of the cost and time.