A surveyor who makes a party wall award and a surveyor who gives evidence about it in court are doing two different jobs under two different sets of rules. From 30 November 2026, the rules for the second job get tighter. Anyone who may need a party wall surveyor expert witness for an award appeal or a damage claim in London should know what changes.
Key Takeaways
- The RICS professional standard “Surveyors acting as expert witnesses”, 5th edition, was published in July 2026 and takes effect on 30 November 2026.
- An appointed party wall surveyor acts under statute when making an award. An expert witness owes an overriding duty to the court.
- The new standard adds duties on conflicts, repeat instructions, AI use, assumptions and acting in a dual role.
- Award appeals, damage claims and works done without notice are the disputes most likely to need independent expert evidence.
Two roles that are often confused
Under the Party Wall etc. Act 1996, each owner may appoint a surveyor, or both may agree on one. Those surveyors settle the dispute by an award. In doing so they act in a statutory role, impartially between the owners. They are not expert witnesses.
Once a dispute reaches court, the position changes. The county court deciding an appeal, or a claim for damage, needs evidence. That evidence comes from an expert witness under CPR Part 35 and Practice Direction 35. The expert’s duty is to the court, and it overrides any duty to the person paying.
When a London dispute needs a party wall surveyor expert witness
Most party wall matters end with an award and never see a courtroom. Expert evidence becomes necessary in a smaller group of cases.
- Award appeals. An owner may appeal an award to the county court within 14 days of service. The court can look again at the technical merits, and usually needs expert help to do so.
- Damage causation. Whether cracking was caused by the neighbour’s excavation or basement works, or was there already. The schedule of condition taken before the works is the starting point.
- Cost of making good and compensation. What repair is reasonable, and what it should cost.
- Works without notice. Where a building owner has started notifiable work without serving notice, the Act’s dispute machinery may not be available and the adjoining owner may have to go to court.
- Injunctions. Urgent applications to stop works often turn on a short expert report about risk to the adjoining structure.
- Fee disputes. Whether surveyors’ fees awarded against an owner are reasonable.
In dense London terraces, with basement digs, loft conversions onto party walls and rear extensions built up to the boundary, each of these arises regularly.
What the 5th edition changes
The new standard replaces the 4th edition. It applies to all RICS members wherever they practise, with local law and court rules taking priority where they differ.
Conflicts and repeat instructions
Experts must disclose regular reliance on the same instructing party for multiple instructions, especially where that work is a significant share of income. Any conflict must be disclosed at once.
This matters in party wall work. The field is small, the same surveyors meet repeatedly, and a surveyor may have acted for a developer on many previous schemes. That history will now need to be stated.
Acting as both expert and advocate
A surveyor should not normally act as expert witness and advocate in the same matter. The dual role is allowed only where the tribunal permits it, it is proportionate, the client has been advised, and the two roles are kept clearly apart.
A related practical point: the surveyor who made the award under appeal is a witness of fact about what happened. An independent expert, with no part in the award, is usually the safer choice for opinion evidence.
Assumptions and alternative conclusions
Reports must identify all assumptions, explain competing schools of thought, and set out alternative conclusions where the opinion depends on disputed facts or law. In a cracking dispute, that means giving an opinion on each version of events: if the crack was present before the works, and if it was not.
AI and other people’s work
Experts must disclose where AI or similar tools were used to produce evidence and identify work done by others. The expert remains personally responsible for every opinion.
Instructions and fees
Experts must verify instructions before accepting, keep a record of instructions and changes, and summarise material instructions in the report. The general ban on conditional or success-based fees stays, with only a narrow exception for pre-existing arrangements disclosed to the tribunal.
Consequences
The standard lists the outcomes of poor practice: criticism by the tribunal, adverse costs, contempt proceedings, negligence claims and RICS disciplinary action.
Expert evidence in practice: what the court expects
A party wall expert report that stands up will usually contain:
- The expert’s qualifications and experience of party wall and structural matters.
- A clear statement of the instructions and the documents reviewed, including the notices, the award and the schedule of condition.
- Findings from the expert’s own inspection, with dated photographs.
- Reasoned opinions on cause, extent and remedy, with alternatives where facts are disputed.
- The Part 35 declaration and statement of truth.
In lower-value disputes the county court will often direct a single joint expert, instructed by both owners. Where each side has its own expert, the court will expect the experts to meet and produce a joint statement of what is agreed and what is not.
What London owners and solicitors should do now
- Decide early whether expert evidence is needed. The 14-day appeal window is short. Take advice on the day the award arrives.
- Choose an expert who was not involved. Independence is easier to show.
- Ask the conflict questions. Past work for the other owner, their surveyor or their contractor.
- Hand over the full file. Notices, award, schedule of condition, drawings, correspondence and photographs.
- Ask about AI and delegation. Who will inspect, who will write, and what tools are used.
- Consider a joint expert. It can halve the expert cost and shorten the dispute.
Frequently Asked Questions
Is my appointed party wall surveyor my expert witness?
No. The appointed surveyor acts impartially under the Act. An expert witness is a separate role with a duty to the court.
How long do I have to appeal a party wall award?
Fourteen days from the date the award is served on you.
Can the same surveyor act for me in the award and give expert evidence on appeal?
That surveyor can give factual evidence about what happened. For independent opinion evidence, a surveyor with no part in the award is usually preferable.
Does the new RICS standard apply to all party wall surveyors?
It applies to RICS members acting as expert witnesses. Party wall surveyors who are not RICS members are not bound by it, although the court rules on expert evidence apply to everyone.
Conclusion
The 5th edition does not change the Party Wall etc. Act 1996, but it changes how surveyors must behave once a party wall dispute reaches court. From 30 November 2026, expect fuller disclosure, more carefully reasoned reports and clearer separation of roles.
Party Wall Surveyor London acts as appointed surveyor under the Act and provides independent expert evidence in award appeals and damage claims across the capital. Contact the team before the appeal deadline runs.