Delay expert witness
for construction disputes
Independent delay expert evidence for international arbitration, adjudication, dispute board proceedings and litigation — extension of time, critical path causation, concurrent delay, disruption and acceleration on major construction and engineering projects.
Delay analysis that
withstands cross-examination
Delay disputes are decided on causation: which events drove the critical path, when, and by how much. A delay expert’s opinion is only as reliable as the programme logic and the contemporaneous records beneath it — and opposing experts will test both.
We work directly from native programme files, validate baselines and updates before relying on them, and select the analysis method that the records, the contract and the forum can support. Where time-related costs are claimed, the delay findings feed directly into the quantum assessment.
Delay expert work is led by Metehan Çağlar Sonbahar, a Chartered Civil Engineer with an LLM in Construction Law and Arbitration, who has given delay and disruption evidence in international arbitration, including cross-examination on extension of time and disruption issues.
"The method follows the records — not the outcome the client would prefer."
Different methods can produce different answers on the same project. We explain why the chosen method is appropriate, and test our conclusions against the alternatives the other side may use.
Delay issues
we address
We act for contractors and employers, and as single joint or tribunal-appointed expert where required.
Extension of time and critical path
Identification of the critical path over time, the events that affected it, and the extension of time properly due under the contract.
Concurrent delay
Analysis of whether competing delays were genuinely concurrent on the critical path, and the consequences under the contract and governing law.
Disruption
Analysis of loss of productivity separate from critical delay, using the records to establish cause and effect.
Acceleration and mitigation
Assessment of acceleration measures, whether instructed or constructive, and of the parties' mitigation of delay.
Programme and record validation
Review of baseline and updated programmes in Primavera P6 and other platforms: logic, constraints, calendars and progress data.
Review of opposing delay evidence
Critical review of the opposing delay analysis, its method, programme manipulation and record gaps, with support to counsel on cross-examination.
Selected delay
expert appointments
Client names and details are withheld for confidentiality. Further representative matters are shown on our Experience page.
600 MW combined cycle power plant
Delay and disruption expert in international arbitration: expert report, oral testimony and cross-examination on extension of time and disruption issues.
304 km highway — CIS
Programming and quantum expert in DAB proceedings on an ADB and World Bank-financed highway, with continuing support in the ICC arbitration that followed.
112 km highway — East Africa
Delay and cost expert on an Islamic Development Bank-funded greenfield road project under the FIDIC Pink Book (2010).
240 MW hydro-power plant
Delay and time-related cost evaluation covering tunnels, cofferdams, dam embankments, power station and hydro-mechanical works.
Tunnelling works — Eastern Europe
Appointed by the Employer to provide an independent expert opinion on the delays that occurred on a tunnelling project, their causes and their effect on completion.
Five-star hotel development — European Union
Appointed by the Contractor to analyse the delays that occurred on a five-star hotel development in the European Union and their effect on completion.
Professional qualifications
underpinning our expert work
Our expert services are led by a practitioner whose qualifications span both the technical and legal dimensions of construction disputes.
Technical foundation across construction, engineering and infrastructure projects — providing the project knowledge that underpins delay and quantum analysis.
Postgraduate legal qualification in construction law and arbitration — bridging the technical and legal dimensions of construction disputes.
Membership of the global centre for dispute resolution practice, reflecting engagement with recognised standards in arbitration.
Member of the Academy of Experts — the UK’s leading professional body for expert witnesses, focused on standards and responsibilities of expert practice.
Postgraduate qualification in construction management providing the project delivery context essential for credible delay and quantum analysis.
Recognised specialist in FIDIC contracts and dispute resolution, including appointments as DAB member under the FIDIC suite.
Delay expert witness — common questions
What does a delay expert witness do in a construction dispute?
A delay expert gives an independent opinion to the tribunal or court on what caused the project to finish late, which events affected the critical path and by how much, and therefore what extension of time is justified. Those findings usually also underpin the time-related quantum.
How is concurrent delay treated?
It depends on the contract and governing law. Under English law, true concurrency generally entitles the contractor to an extension of time but not to prolongation costs, an approach reflected in the SCL Protocol. Other jurisdictions and some contracts take different approaches, including apportionment.
Can you work from native Primavera P6 files?
Yes. We work directly from native P6 (XER) files and other scheduling formats, which allows logic, constraints, calendars and progress data to be examined — not just the printed bar charts.
Can you review the other side's delay analysis?
Yes. We review opposing delay evidence for methodological weaknesses, programme manipulation and gaps in the records, and support counsel in preparing cross-examination.
Need a delay expert for a construction dispute?
Contact Equitas to discuss the matter, the forum and the timetable. Initial discussions are confidential.