A subsidence dispute typically lands on a homeowner's desk in one of three ways. A neighbour's tree is suspected of causing damage to your foundations. A neighbour has carried out work, an extension, a basement, drainage alterations, and your property has subsequently developed cracking. Or your buildings insurer has refused or under-scoped a claim and you are considering legal action. In every one of those situations the determinative document is a CPR Part 35 compliant expert witness report from an independent, suitably qualified engineer.
What CPR Part 35 actually requires
Civil Procedure Rule Part 35 governs expert evidence in English and Welsh civil litigation. A compliant expert witness report sets out the expert's qualifications, the instructions received, the materials reviewed, the site work undertaken, the technical opinion reached, the reasoning behind it, and an explicit acknowledgement of the expert's overriding duty to the court (not the instructing party). It is signed with a statement of truth and is in a format that the court can rely on directly. Our reporting engineers are practising expert witnesses with current court and tribunal experience.
The four dispute types we cover most
- Neighbour-tree subsidence. Where a tree on a neighbouring property is suspected of causing root-influenced clay shrinkage and structural damage. Evidence required: arboricultural identification, soil sampling, foundation investigation, structural assessment, and a causation opinion that meets the legal test for nuisance.
- Construction-induced damage. Adjacent extensions, basement excavations, or drainage works that have allegedly caused settlement or vibration damage to your property. Evidence required: ideally a pre-construction schedule of condition, plus a post-event survey, and a causation opinion ruling in or out alternative causes.
- Party-wall disputes. Where party-wall works are alleged to have caused damage, or where notices and surveyor appointments under the Party Wall etc. Act 1996 are contested. Our role is the independent technical evidence on damage, cause and remedy.
- Insurance claim disputes escalated beyond the Ombudsman. Where a subsidence insurance dispute is heading to court rather than the Financial Ombudsman Service, a CPR-compliant expert report is required.
What an expert witness report contains
- Expert's qualifications, experience and CPD record.
- Statement of instructions and materials reviewed.
- Site inspection notes with photographs.
- Underlying technical investigation, drainage CCTV, root or soil assessment, monitoring data, as needed.
- Engineering opinion on cause, supported by reasoning.
- Opinion on liability where instructed (legal test, not just technical).
- Opinion on remedy and quantum where instructed.
- CPR Part 35 declaration and statement of truth.
- Statement of independence and any matters that might affect that.
Why independence matters even more in dispute work
In litigation the expert's overriding duty is to the court. A report from an expert who is also commercially aligned to a repair contractor, or whose firm depends on instructions from one side of the typical dispute, is open to attack on cross-examination, and rightly so. Our engineers are commercially independent of the entire repair industry. We do not seek volume work from insurers, claimant solicitors or contractors in a way that would compromise that. The point is that the report has to survive the other side reading it carefully and looking for any reason to discount it. Ours do.
Acting for claimant or defendant
We act on both sides. Where there is no current conflict, we will accept instructions from either a homeowner pursuing a dispute, the defendant homeowner being pursued, an insurer or its solicitor in a recovery action, or as a single joint expert appointed by both parties (an increasingly common and cost-effective route).
For solicitors
We work directly with solicitors on subsidence-related matters and provide pre-action technical opinions, full CPR reports, joint statements with opposing experts, written responses to Part 35 questions, and oral evidence at trial. Fees are quoted at instruction and split into clear technical investigation, report drafting, meetings, joint-statement work and court attendance components. Where the value of the dispute warrants it, we are happy to provide an initial pre-instruction assessment.
For solicitors and homeowners, how engagements are scoped
Expert-witness engagements are scoped to the dispute. The standard components are a pre-action technical opinion, a full CPR Part 35 report, a joint statement with the opposing expert, written responses to Part 35 questions and, where required, court attendance. Each component is quoted at instruction and split clearly so that the cost of each stage of the dispute is transparent. Where the value of the dispute warrants it, an initial pre-instruction assessment is available.
Need an independent expert? Send a short summary of the dispute and a qualified specialist will respond with a proposal and a likely timetable.
The neighbour-tree dispute, what the law actually requires
Tree-root subsidence disputes between neighbours are the single most common category of expert-witness work we see. The legal test in England and Wales follows the well-established line of authority fromSolloway v Hampshire County Council through to the more recent appellate decisions: the claimant must show that the defendant's tree caused the damage, that the damage was reasonably foreseeable, and that the defendant failed to take reasonable preventative steps. Each of those three limbs requires specific evidence. Causation usually rests on root identification, soil sampling and a structural opinion linking the soil movement to the building damage. Foreseeability rests on the species, the proximity, the soil class and any prior history at the property. The reasonable steps test rests on what the defendant knew and what management of the tree would have been proportionate. A well-constructed expert report covers all three limbs in order.
How a single joint expert engagement works
Where both sides in a dispute agree to a single joint expert (often encouraged by the court for proportionality reasons), our engineer is instructed jointly under a shared letter of instruction signed by both parties' solicitors. Costs are shared equally unless the instruction states otherwise. The expert's overriding duty remains to the court, not to either instructing party. The deliverable is a single report addressing the agreed list of issues, and where appropriate a single oral evidence appearance. The economics are substantially better for both sides than a contested two-expert engagement, and the technical narrative the court receives is cleaner.
Preparing for oral evidence, what to expect on the day
Where an expert report is challenged at trial, the expert is called to give oral evidence and is cross-examined by counsel for the opposing party. The expert's role is unchanged: to answer the court's questions honestly, to defend the opinions in the report on their evidential basis, and to concede ground where the cross-examination identifies a legitimate weakness. Our engineers are trained and practised in cross-examination and will sit with instructing solicitors at any pre-trial conference required. We will not coach an opinion to favour the instructing party; the rules of expert evidence and our own professional registration prohibit it.