The role of an expert witness in a building dispute is to provide objective, qualified, documented evidence of the facts in dispute.


Engaging an expert witness is usually a complex and expensive exercise and the expert’s role as an impartial observer, and not an advocate for the instructing party, is often misunderstood.


Parties to a dispute can become anxious when it appears that the expert they have retained is not ‘on their side’ or that the other party’s expert is an ‘opponent’ in disputed proceedings. It is therefore helpful to understand the role of expert witnesses, their obligations to a tribunal or court and how they can assist in determining a building dispute.


What is an expert witness?

An expert witness is a qualified professional with specialised technical knowledge in a particular area or industry and the necessary skills to provide an opinion, in writing and verbally. This opinion may be used as evidence in negotiations, dispute resolution processes or during tribunal or court proceedings.


When and why is an expert used?

The role of the expert is to assist the parties in negotiating a settlement, or if the matter proceeds to a tribunal or court, guide it towards a reasonable determination.


A domestic building dispute does not typically concern the interpretation of a contractual term, which, in a court or tribunal, would be a matter for lawyers to argue.


Rather, a building dispute typically concerns claims of incomplete and / or defective construction work the nature of which is technical and industry specific. The subject matter of the dispute may be a single dwelling or a multi-storey residential complex.



A layperson is not qualified to provide evidence of a technical nature which, in court or tribunal proceedings, could be considered an opinion or hearsay. In such matters evidence should be given by a person with specialised knowledge in the subject matter based on his or her training, study or experience.


Similarly, a lawyer is not qualified to assess the costs of building rectification.


Retaining an expert witness

The selection of an expert witness is typically made by the lawyer representing a party to the dispute, who will identify a professional with the necessary expertise required for the particular case and the ability to provide written, and oral evidence, if required.


Written instructions should be provided to the expert which will include an overview of the matter, the issues in dispute, the matters to be addressed, and additional information that will assist in compiling the report, such as building contracts, plans and specifications.


Most unresolved domestic building disputes are heard in a tribunal with specific rules and codes of conduct regarding the use of an expert witness and the required format for expert reports to ensure consistency and uniformity. A copy of the relevant expert evidence guidelines and reporting requirements from the tribunal should always accompany the instructions.


It may also be necessary to engage an additional expert with specialist knowledge, such as a structural engineer, to provide a supplementary report for specific issues like a defective retaining wall.


A quantity surveyor may be engaged to assess the cost of rectification works for more complex matters. For simple matters, obtaining quotes from building professionals and tradespersons may be sufficient.


The expert reportAn expert will draw upon his or her construction knowledge to provide a qualified opinion in response to the issues raised in the instructions. A report will typically include:

• the expert’s formal qualifications, experience and field of expertise in which the evidence is being provided;
• a summary of the issues upon which the expert is required to report;
• any facts or assumptions upon which the expert has relied (i.e. the letter of instruction);
• the identification (and categorisation) of incomplete / non-compliant / defective building work;
• an opinion as to why the building work is incomplete / non-compliant / defective qualified with reference to relevant standards, construction codes and tolerances, and the building contract, plans and specifications;
• any examinations, investigations or tests used to form the opinion;
• an assessment of the cause of a defect;
• recommendations for the rectification of incomplete / non-compliant / defective building work including reasons for the recommendation;
• suggested methods for rectifying the incomplete / non-compliant / defective building work including any reasonable alternative remedies;
• the estimated cost of the recommended rectification work.

The duty of impartialityTribunal and court rules, practice notes and directions require that an expert witness is impartial and not an advocate for a party to a proceeding. He or she has an overriding duty to assist a tribunal or court on the matter relevant to the expert’s expertise.


Independence is paramount and any hint of bias towards the instructing party by the expert can be detrimental to that party’s case and may initiate a request by the opposing side for the tribunal to disregard that expert’s evidence.


The expert’s reputation and credibility in such circumstances will also be at stake.


ConclusionAn expert witness may be retained to provide an impartial qualified opinion to assist in determining a matter in dispute.


Choosing an expert with the requisite qualifications, knowledge and experience to provide an objective opinion (and understanding that an expert is not an advocate for the instructing party) is essential for all building disputes.


If you or someone you know wants more information or needs help or advice, please contact us on 03 8787 8900 or email law@davidnaidoo.com.au.


Reference URL: https://www.davidnaidoo.com.au/the-role-of-an-expert-witness-in-a-building-dispute/