Defects and disputes: the expert witness perspective on common construction failures

Construction disputes rarely arise from nowhere. The defects and failures that generate litigation almost always have roots in decisions — or absences of decision — made much earlier in the project.

Construction accounted for one in nine business insolvencies in the UK in 2023 — one of the highest rates of any sector –  BCIS / Julian Hobbs & Co analysis, 2025

The construction industry generates more litigation per pound of output than almost any other sector. Dispute resolution (adjudication, arbitration, and litigation) is a significant and growing line item for developers, contractors, and professionals alike. Yet the overwhelming majority of disputes that Wakemans’ expert witness team encounters were not inevitable. They arose from identifiable failures that an experienced eye would have caught earlier.

Understanding the most common failure patterns is useful not just for those already in dispute, but for everyone involved in projects where those patterns might be developing. Prevention is always cheaper than expert witness testimony — but knowing what to look for is the starting point.

The most common defect categories

Water ingress and envelope failures. The most frequently recurring category in building surveying disputes. Flat roofs, parapet details, cladding interfaces and window installations all generate disproportionate claim volumes relative to their cost. In almost every case, the failure has a traceable origin: a design detail that was value-engineered, a specification that was amended on site without formal instruction, or an installation that was not inspected at the critical stage.

Ground conditions and foundation failures. Significant claims frequently arise from conditions that were discoverable, but crucially not actually discovered, before construction began. A ground investigation that was scoped to minimise cost rather than risk, or a desk study that was treated as a substitute for a physical investigation, regularly appears in the evidence behind foundation-related disputes.

Fire and building safety compliance. The Building Safety Act 2022 has raised the stakes considerably for higher-risk buildings. The Building Safety Regulator approved only 14% of HRB Gateway 2 applications as compliant in the year to September 2024. Where design and specification have not been rigorously coordinated through the pre-construction phase, compliance failures become defect claims – and in some cases, criminal exposure for duty holders.

In our experience, the paper trail tells the story. The question is whether the evidence supports the party who was careful or exposes the one who wasn’t.

What makes an effective expert witness report

The courts and adjudicators have specific expectations of expert witness evidence. The expert’s duty is to the court, not to the party who appointed them, a principle that is tested under cross-examination. A report that reads as advocacy will be treated as such. A report that demonstrates genuine independence, methodical analysis, and clear reasoning on contested technical points carries weight.

Wakemans’ expert witness practice provides authoritative testimony across building defects, professional negligence, and construction contract disputes. Our reports are written to meet the technical requirements of the Civil Procedure Rules and the expectations of adjudicators under the Scheme for Construction Contracts. We work across all sectors: industrial and logistics, hotels and leisure, residential and commercial — and our team’s breadth of practical project experience underpins the credibility of our evidence.

The prevention argument

Most of the disputes our expert witness team is instructed on involve defects or failures that would have been identifiable much earlier – by a building surveyor at acquisition, a cost consultant reviewing value engineering proposals, or a principal designer reviewing a design change. The expert witness role exists because things go wrong. The goal, from Wakemans’ perspective, is to help clients ensure fewer things do.

Wakemans provides expert witness services across construction defects, professional negligence, and contract disputes. Speak to our team for an initial discussion about your case.

Learn more at wakemans.com/expertise/expert-witness