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Only around 15% of chartered surveyors in England and Wales have ever produced a CPR Part 35 compliant expert report — yet demand for qualified single joint experts (SJEs) in property and construction disputes continues to outpace supply in 2026. For building surveyors with solid technical credentials, that gap represents a genuine career opportunity. Making the move from surveyor to single joint expert requires more than professional competence, however. It demands a clear understanding of court obligations, report structure, conflict management, and the distinct mindset shift that CPR Part 35 demands.
This guide sets out the practical steps for any building or valuation surveyor looking to transition their practice into CPR 35 expert witness work, with particular focus on the single joint expert role.
Key Takeaways
- CPR Part 35 places the expert's primary duty to the court, not to either instructing party — a fundamental shift from standard surveying practice.
- The single joint expert role requires specific training, conflict-of-interest checks, and a strictly structured report format.
- Impartiality, intellectual honesty, and clear communication are the qualities courts assess most heavily when evaluating expert credibility.
- Surveyors must respond promptly and substantively to Part 35 written questions or risk court sanctions and reputational damage.
- Continuous professional development, including RICS-accredited expert witness training, is essential for maintaining competence in this specialist role.
Understanding CPR Part 35 and the Single Joint Expert Role
Before making the transition from surveyor to single joint expert, it is essential to understand exactly what CPR Part 35 requires and how the SJE role differs from acting as a party-appointed expert.
What CPR Part 35 Actually Requires
CPR Part 35 governs the use of expert evidence in civil litigation in England and Wales. Its central principle is that an expert's overriding duty is to the court, not to the party who instructs or pays them [1]. This is a profound departure from the advisory role most building surveyors are accustomed to. In standard practice, a surveyor acts in the client's interest. Under CPR Part 35, that dynamic is reversed — the court's need for objective, impartial technical assistance takes precedence over everything else.
Practice Direction 35 supplements the rules by specifying what an expert report must contain. Reports that fail to comply with these requirements risk being dismissed or attracting cost penalties [3]. The mandatory contents include:
- A statement that the expert understands their duty to the court
- Details of the expert's qualifications and experience
- The substance of all instructions received
- A summary of the range of opinion on each issue, where opinions differ
- The expert's conclusions and the reasoning behind them
- A statement of truth
The Single Joint Expert: A Distinct Appointment
In many lower-value or procedurally straightforward disputes, the court will direct that a single joint expert be appointed rather than allowing each party to instruct their own expert. The SJE is jointly instructed by both parties (or all parties) and reports to the court as a neutral technical adviser.
This arrangement carries particular responsibilities. The SJE must serve both parties with equal diligence, communicate transparently with all sides, and resist any pressure — however subtle — to favour one party's position. Understanding the full scope of what a chartered surveyor does in professional practice provides a useful foundation, but the SJE role adds a legal dimension that requires deliberate preparation.
Practical Steps for Transitioning Into CPR 35 Expert Witness Work
The transition from surveyor to single joint expert is not a single event — it is a structured process that involves training, practice development, and careful management of each instruction from the outset.
Step 1: Acquire Specialist Training
The starting point for any surveyor entering expert witness work is formal training. The RICS Accredited Expert Witness Training programme is the most widely recognised qualification in this field [4]. It covers the legal framework of CPR Part 35, report writing standards, courtroom procedure, and the ethical obligations of the expert. Completing this training signals to solicitors and courts that the surveyor has made a deliberate commitment to the role rather than simply accepting an ad hoc instruction.
Other useful training routes include:
- The Academy of Experts membership and training courses
- The Expert Witness Institute programmes
- Continuing professional development workshops run by RICS and specialist legal training providers
Surveyors should not accept their first SJE instruction without completing at least one structured training programme. The consequences of producing a non-compliant report — including costs sanctions and reputational damage — are too significant to risk on the basis of technical expertise alone [1].
Step 2: Define Your Area of Expertise
Courts and solicitors value experts who operate within clearly defined boundaries. A surveyor who specialises in residential building defects should not accept instructions involving complex commercial dilapidations unless that work falls squarely within their professional experience. Overreaching beyond genuine expertise is one of the most common and damaging errors an expert can make [2].
Building surveyors with experience in level 3 building surveys are well positioned to act as SJEs in disputes involving structural defects, damp, drainage failures, and building condition assessments. Those with a background in dilapidation surveys may find a natural pathway into landlord and tenant disputes. Surveyors experienced in party wall matters may be instructed in boundary and neighbourly disputes.
Being specific about your area of expertise in marketing materials, professional profiles, and when responding to solicitor enquiries will build credibility and attract appropriate instructions.
Step 3: Conduct Thorough Conflict Checks Before Accepting Instructions
When a solicitor or court contacts a surveyor to act as an SJE, the first obligation before accepting is to conduct a rigorous conflict-of-interest check. This means reviewing:
- Whether the surveyor has previously advised either party on the same or related matter
- Whether the surveyor has a financial or personal interest in the outcome
- Whether any professional relationship exists with either party's legal team
- Whether the surveyor has previously expressed a firm opinion on the specific issue in dispute
Even an appearance of conflict can undermine the SJE's credibility and expose them to challenge. If any potential conflict is identified, the surveyor must disclose it immediately to both parties and, if necessary, decline the instruction. Transparency at this stage protects all parties and preserves the integrity of the process.
Step 4: Manage the Joint Instruction Carefully
Once appointed, the SJE must manage communications with both parties with scrupulous fairness. Practically, this means:
| Communication Rule | Why It Matters |
|---|---|
| Copy all correspondence to both parties | Prevents accusations of bias or private advice |
| Do not meet privately with one party | Undermines neutrality and may breach court directions |
| Respond to written questions from both sides | Required under CPR 35.6; evasive responses risk sanctions [2] |
| Seek clarification from both parties jointly | Ensures the scope of the report is agreed |
The SJE's instructions will typically be set out in a joint letter of instruction agreed between the parties' solicitors. The surveyor should read this carefully, confirm the scope in writing, and raise any concerns about ambiguity or unrealistic timescales before beginning work.
Step 5: Structure the Expert Report to CPR 35 Standards
The expert report is the centrepiece of the SJE's work. A properly prepared CPR 35 compliant report explains methodology, reasoning, and conclusions in a structured format that ensures clarity and objectivity [5]. The report must not read like a client-facing survey report — it is a document addressed to the court.
Key structural elements include:
- Cover page identifying the case name, court, and expert's details
- Executive summary setting out the key conclusions
- Scope of instructions reproduced from the joint letter of instruction
- Methodology describing how the inspection and analysis were conducted
- Factual background setting out the relevant history of the property and dispute
- Technical analysis addressing each issue raised in the instructions
- Range of opinion where professional opinion may reasonably differ
- Conclusions stated clearly and without advocacy
- Statement of truth and expert declaration as required by PD 35
The language throughout should be plain, precise, and free from jargon. Courts are not made up of building professionals, and the expert's value lies partly in translating technical complexity into clear, accessible findings. This mirrors the discipline required when producing a thorough level 3 building survey report — but with a legal audience in mind rather than a residential buyer.
Maintaining Impartiality and Credibility in the SJE Role
The qualities that make a surveyor technically competent are not always the same qualities that make them an effective expert witness. Courts assess credibility based on independence, intellectual honesty, clarity of communication, responsiveness to questions, and professional presentation [2].
The Mindset Shift: Adviser to Neutral
The most significant challenge for surveyors entering expert witness work is the mindset shift required. In standard practice, a surveyor is hired to help a client achieve an outcome. In the SJE role, the surveyor is hired to help the court understand the facts. These are fundamentally different objectives.
"The expert witness who tries to help their instructing party win will almost always be less persuasive than the expert who simply tells the court what the evidence shows."
Surveyors who struggle to separate their technical findings from an advocacy position will find their credibility challenged, their reports questioned, and their future instructions reduced. Genuine impartiality is not just an ethical requirement — it is a practical necessity for building a sustainable expert witness practice.
Responding to Part 35 Written Questions
Under CPR 35.6, parties may submit written questions to the SJE following receipt of the report. These questions must be answered substantively and promptly. Evasive, incomplete, or delayed responses can damage credibility and may result in court sanctions [2].
Best practice when responding to Part 35 questions includes:
- Answering each question directly and in numbered sequence
- Acknowledging where a question raises a point not addressed in the original report
- Correcting any factual error identified by the questions without defensiveness
- Declining to answer questions that go beyond the scope of the original instruction — but explaining why clearly
Participating in Expert Conferences
Courts may order an expert conference (sometimes called a "without prejudice" meeting or a "hot tub" session) where the SJE meets with any party-appointed experts to identify areas of agreement and disagreement. Effective participation in these conferences demonstrates impartiality and enhances credibility [2]. The SJE should prepare a clear schedule of the issues, be willing to concede points where the evidence supports it, and avoid positional bargaining.
Common Pitfalls to Avoid
Surveyors new to expert witness work should be aware of the following errors that consistently undermine credibility [2]:
- Overreaching: Expressing opinions on matters outside the surveyor's expertise
- Inconsistency: Taking different positions in the report and in responses to questions
- Ignoring contrary evidence: Failing to acknowledge evidence that does not support the conclusions
- Excessive advocacy: Writing the report as though acting for one party
- Poor documentation: Failing to retain inspection notes, photographs, and working papers
- Defensive testimony: Becoming argumentative or evasive when challenged
Building a Sustainable Expert Witness Practice
Transitioning into CPR 35 work is one thing; building a practice that generates consistent instructions is another. The following steps will help surveyors establish themselves in this specialist market.
Develop a Professional Profile
Solicitors and courts need to be able to verify an expert's credentials quickly. A clear professional profile should include:
- RICS membership and relevant specialist accreditations
- A list of dispute types and property sectors covered
- Details of any expert witness training completed
- A summary of previous expert witness experience (without breaching confidentiality)
- Geographic coverage — for example, surveyors operating across North London or Essex should make their service areas explicit
Listing on the RICS Expert Witness Register and the Expert Witness Institute directory will increase visibility with instructing solicitors.
Invest in Continuous Professional Development
The legal framework governing expert evidence is not static. CPR Part 35 has been subject to ongoing judicial interpretation, and 2026 has seen continued emphasis on proportionality and the efficient use of expert evidence in lower-value disputes [3]. Surveyors must stay current with procedural updates, relevant case law, and emerging technical standards in their area of expertise [7].
Investing in advanced technologies — such as drone surveys for boundary disputes — can also enhance the quality of evidence presented, provided the data is gathered and presented in a manner that complies with legal standards [6]. For surveyors working on complex structural matters, familiarity with structural engineering reports and their evidential value will strengthen the quality of expert opinion provided.
Set Clear Fee Arrangements
Expert witness work commands higher fees than standard survey instructions, reflecting the additional legal responsibility involved. Surveyors should set fees on a time-cost basis rather than a fixed fee, as the scope of instructions can expand significantly once Part 35 questions are received. Fee arrangements must be disclosed in the expert report and must not be contingent on the outcome of the case — conditional fee arrangements for expert witnesses are prohibited under CPR Part 35.
Conclusion
The path from surveyor to single joint expert is demanding but achievable for any building or valuation surveyor willing to invest in the right training, adopt the correct mindset, and approach each instruction with rigorous impartiality. The transition requires a clear understanding of CPR Part 35's requirements, disciplined conflict checking, careful management of joint instructions, and a structured approach to report writing that serves the court rather than any individual party.
Actionable next steps for surveyors considering this transition:
- Enrol in the RICS Accredited Expert Witness Training programme or an equivalent course before accepting any expert witness instruction.
- Define the specific dispute types and property sectors where your technical expertise is strongest, and limit your practice to those areas.
- Develop a professional profile and register with the RICS Expert Witness Register and the Expert Witness Institute.
- Review a selection of CPR 35 compliant expert reports to understand the required format and tone before drafting your first report.
- Establish a clear conflict-of-interest checking process and document it as part of your practice management procedures.
- Commit to ongoing CPD to remain current with procedural changes and technical developments in your specialist area.
The demand for credible, court-ready building surveyors acting as single joint experts is real and growing. Surveyors who make this transition thoughtfully and systematically will find it among the most professionally rewarding and commercially valuable moves they can make in 2026.
References
[1] First Time Expert Witness Surveyor Step By Step Guide To Your First Cpr Part 35 Instruction In Property And Construction Disputes – https://wimbledonsurveyors.com/first-time-expert-witness-surveyor-step-by-step-guide-to-your-first-cpr-part-35-instruction-in-property-and-construction-disputes/?utm_source=openai
[2] Expert Witness Impartiality Under Cpr Part 35 Building Surveyors Guide To Courtroom Credibility In 2026 – https://kingstonsurveyors.com/expert-witness-impartiality-under-cpr-part-35-building-surveyors-guide-to-courtroom-credibility-in-2026/?utm_source=openai
[3] Civil Procedure Rules Compliance In Valuation Expert Witness Reports 2026 Updates For Surveyors – https://www.canterburysurveyors.com/blog/civil-procedure-rules-compliance-in-valuation-expert-witness-reports-2026-updates-for-surveyors/?utm_source=openai
[4] Expert Witness – https://www.smartsurveyor.co.uk/roles/expert-witness?utm_source=openai
[5] Construction Disputes And Cpr 35 Compliant Expert Reports Authority Guide To Instructing An Expert Witness Surveyor On Construction And Builder Disputes – https://www.res-prop.com/construction-disputes-and-cpr-35-compliant-expert-reports-authority-guide-to-instructing-an-expert-witness-surveyor-on-construction-and-builder-disputes/?utm_source=openai
[6] Expert Witness Roles In Cpr Part 35 Boundary Disputes Turning Drone Surveys Into Courtroom Evidence 2026 – https://kingstonsurveyors.com/expert-witness-roles-in-cpr-part-35-boundary-disputes-turning-drone-surveys-into-courtroom-evidence-2026/?utm_source=openai
[7] Expert Witness Services – https://www.clystcore.co.uk/expert-witness-services?utm_source=openai
