
Whether you are facing a construction dispute, a defect claim, or a complex quantum disagreement, having the right expert witness in your corner can be the difference between a favourable outcome and a costly, drawn-out battle. At ClystCore Chartered Surveyors, our RICS-regulated expert witness services deliver independent, court-compliant professional opinion across both building surveying and quantity surveying disciplines, covering the entirety of the UK.
An expert witness is a suitably qualified professional appointed to provide an independent, impartial opinion on technical matters that fall outside the general knowledge of a court, tribunal, or adjudicator. In surveying and construction disputes, this expertise is invaluable, helping decision-makers understand complex issues relating to building defects, construction costs, contractual entitlements, and professional negligence.
Unlike a standard consultant who advises their client, an expert witness's overriding duty is to the court or tribunal, not to the party who instructs them. This principle is enshrined in CPR Part 35 (Civil Procedure Rules), which governs expert evidence in civil proceedings across England and Wales. At ClystCore, we take this duty with the utmost seriousness. Our reports are always our own, independent, and evidence-based; never shaped by the pressures of the instructing party.
ClystCore offers expert witness appointments across two core disciplines:
Building Surveying Expert Witness:- covering building defects and pathology, breach of duty and professional negligence claims, pre-purchase survey disputes, and reinstatement cost assessment disputes.
Quantum Expert Witness:- providing forensic cost analysis and independent opinion on construction cost disputes, disruption and prolongation claims, contractor and subcontractor claims, employer's deductions, and full adjudication, mediation, and litigation support.
Engaging ClystCore as your expert witness adds real, measurable value to your dispute or legal process:
ClystCore operates in full compliance with the RICS Professional Standard: Surveyors Acting as Expert Witnesses, which sets out the requirements for RICS members providing expert evidence in civil proceedings, covering engagement terms, conflict of interest management, fee arrangements, and report preparation. The 5th Edition of this standard is expected to come into effect in 2026, and ClystCore will implement all updates accordingly.
All of our expert witness work also adheres to CPR Part 35 and Practice Direction 35, the Ikarian Reefer principles of objectivity and independence, and the RICS Practice Alert (2025), which reinforces that expert opinion must be entirely within the expert's own personal professional expertise.
Our expert witness services are regularly sought by solicitors and law firms, property owners and developers facing defect claims, contractors and subcontractors in final account disputes, insurance companies and loss adjusters requiring independent technical opinion, and employers and funders needing independent assessment of contractor claims.
If your dispute requires independent, impartial, and technically credible expert witness evidence in building surveying or construction quantum, ClystCore Chartered Surveyors is ready to help. We are RICS-regulated, based in the South West, and available to accept instructions across England and Wales. Contact us today to discuss your requirements in complete confidence.



Explore how our professional surveying expertise can support every stage of your property journey.
ClystCore provides detailed RICS Home Survey assessments, delivering clarity and confidence for property buyers.
ClystCore delivers precise Quantity Surveying guidance, ensuring cost certainty and value throughout every construction project phase.
ClystCore delivers precise reinstatement assessments, ensuring properties are insured for accurate rebuild costs and full protection.
Independent, clear and professional expert witness reporting for quantum, contractual and construction disputes.
ClystCore acts as your dedicated Employer’s Agent, safeguarding project delivery, contract compliance, and client interests throughout.
We provide independent monitoring, safeguarding funder interests through structured oversight, financial clarity, and evidence-based reporting.