Expert Witness in Building Disputes: When and How

Q: What is an expert witness in building disputes?

An expert witness is a qualified professional appointed to provide independent, objective technical evidence to help the court or tribunal understand building-related issues. In building disputes, expert witnesses are typically chartered building surveyors, structural engineers or fire engineers who can give evidence on matters such as building defects, the cause and extent of damage, the cost of remedial works, compliance with building regulations, dilapidations, and party wall matters. The expert's duty is to the court, not to the party that instructed them.

Q: What is a single joint expert?

A single joint expert (SJE) is an expert witness appointed jointly by both parties (or by the court) to provide a single, independent opinion on a technical matter. SJEs are commonly used in lower-value disputes and in the First-tier Tribunal (Property Chamber) where the proportionality principle means that the cost of each party appointing their own expert cannot be justified. The SJE must be acceptable to both parties and must maintain strict independence. Both parties can submit questions to the SJE, whose report is addressed to the court.

Q: What are the expert's duties to the court?

Under Part 35 of the Civil Procedure Rules, an expert witness has an overriding duty to the court. This means the expert must provide objective, unbiased evidence regardless of which party has instructed them, must not act as an advocate for the instructing party, must clearly state the facts and assumptions on which their opinion is based, must identify matters outside their expertise, and must acknowledge where there is a range of opinion on a matter and explain their own position within that range. Failure to comply with these duties can result in the court refusing to rely on the expert's evidence.

Q: How much does an expert witness cost?

Expert witness fees for building disputes depend on the complexity of the case, the amount of inspection, analysis and reporting required, and whether the expert is required to attend court or tribunal. Fees typically range from £5,000 to £15,000 for a straightforward case with a single issue, to £20,000 to £50,000 or more for complex multi-issue disputes requiring extensive investigation, multiple site visits and court attendance. The fee should be proportionate to the value of the dispute and the complexity of the issues.

Overview

The role of expert witnesses in building disputes

Building disputes, whether concerning defects, dilapidations, party walls or professional negligence, often require technical evidence that is beyond the knowledge of the court. An expert witness provides independent, objective analysis and opinion to help the court or tribunal understand the technical issues and reach a fair decision.

When expert evidence is needed

Expert evidence is needed when the dispute involves technical questions that require specialist knowledge, such as the cause and extent of building defects, whether works comply with building regulations or standards, the cost of remedial works, the valuation of dilapidations claims, fire safety compliance, and structural adequacy. The court controls the use of expert evidence and will only permit it where it is reasonably required to resolve the issues.

Duties to the court

An expert's overriding duty is to the court, not to the party that instructs them. Under CPR Part 35, the expert must provide objective, unbiased evidence, clearly state facts and assumptions, identify matters outside their expertise, and acknowledge where there is a range of opinion. This independence is what gives expert evidence its weight.

Single joint experts

In lower-value disputes, the court may direct that a single joint expert (SJE) be appointed by both parties. This saves costs and provides a single opinion for the court. SJEs are common in the First-tier Tribunal and in Technology and Construction Court cases below a certain value. Both parties can submit questions to the SJE.

FAQ

Frequently asked questions

What is an expert witness in building disputes?

A qualified professional providing independent, objective technical evidence to help the court understand building-related issues. Their duty is to the court, not to the instructing party.

What is a single joint expert?

An expert appointed jointly by both parties to provide a single opinion. Common in lower-value disputes and tribunals where separate experts would be disproportionate.

What are the expert's duties to the court?

Provide objective, unbiased evidence; clearly state facts and assumptions; identify matters outside their expertise; acknowledge ranges of opinion; and not act as an advocate.

How much does an expert witness cost?

£5,000 to £15,000 for straightforward cases; £20,000 to £50,000+ for complex multi-issue disputes. Fees should be proportionate to the dispute value and complexity.

Next Steps