Calling in the experts: Engaging an Expert Witness in property and construction disputes

July 30, 2024
Engaging an Expert Witness - Rory Crosbie

The world of property and construction is becoming ever more litigious. With property transactions and projects often involving multiple parties and agreements between property owners and occupiers, landlords and tenants, developers, contractors and territorial authorities, it’s inevitable that disputes will sometimes occur over costs, timings and other contractual terms.

Nowadays those who own, occupy and construct buildings are well advised to prepare for when – rather than if – a claim is made against them. If you receive a claim it can feel like the world is ending, but it’s a case of drawing breath and seeking legal advice to devise a strategy to fight the claim.

While legal teams have expert knowledge of the law, when a dispute involves highly technical or scientific subject matter, such as that in many building and property disputes, there is also a need for specialist expertise, forensic evidence and impartial opinion to help the parties come to a resolution.

This is the role of the Expert Witness – a role that Prendos has extensive experience in. It’s also our experience that the best results come when legal teams engage us from the outset, so we can provide expert input into devising a successful strategy for fighting the claim.

Whose side is the Expert Witness on?

While the expert witness is usually engaged by the client or their legal counsel and undertakes to provide a service to them, their overriding duty is to assist the court impartially – not to advocate for their client. This means the expert witness must give their evidence honestly, even if this is contrary to their client’s interests and does not advance their case.

It’s extremely important then to choose the right expert witness for your case, so they will be helpful in persuading the other parties, or the court, to reach the desired conclusions.

How to choose the right Expert Witness

Choosing the right expert witness to help comes down to a few key factors, which all require some time to research. It’s critical to dedicate enough time to this process, as the ‘right’ expert witness is very likely a busy professional, and unlikely to be available at short notice. They’ll also need plenty of time to review the case and read all of the documentation necessary to familiarise themselves with it, so be sure to start the search for an expert witness early.

When seeking out an expert witness to assist with your case, there are several things to look for. Don’t be afraid to ask questions to ensure that your expert witness is the right person for your case. An experienced expert witness will be happy to provide answers, as well as proof of their experience and results – albeit client confidentiality may mean there are limits on what can be shared about actual cases.

Professional qualifications and experience

It goes without saying that an expert witness needs to be well versed in the subject matter in question. A high level of professional qualification should be a minimum requirement when choosing an expert witness, along with several years’ experience practicing their profession at a senior level. Professional membership of relevant industry bodies is also a good indicator that they are committed to professional development and ethical codes of practice. These include NZIBS and RICS for building surveyors, NZIQS for quantity surveyors, NZIV for valuers, NZIA for architects, and Engineering New Zealand for structural engineers.

But what if you’re unsure what type of expert will be best suited to give evidence in your case? In the case of a dispute over a building with weathertightness issues, would it be best to engage a building surveyor with extensive experience in assessing the condition of defective buildings, or an architect qualified to peer review weathertightness remediation designs, or a quantity surveyor who is adept at calculating remediation costs? That’s where the multi-disciplinary expertise at Prendos can be extremely useful, and a quick preliminary conversation can help us to direct you to the appropriate expert.

Communication and persuasion skills

While the right specialist expertise is essential, so too is the ability to effectively communicate complex information. An expert witness has the job of explaining highly technical and scientific points so that the lay person can understand. They must present their independent evidence and unbiased opinion in a way that educates and informs, giving the parties solid grounds from which to negotiate, or the court sufficient grounds to make a decision.

When choosing an expert witness, their ability to explain complex concepts in easily understandable terms should be clear. If their emails are overly verbose and their writing opaque, or if they are confusing to converse with, they may not be the right fit for the expert witness role. While the facts may all point in your favour, if the expert witness can’t explain the evidence clearly and persuasively, they will be of very limited use to your case.

Experience of the legal and dispute resolution process

Dispute resolution, whether in or out of court, can be gruelling and uncomfortable. Expert witnesses need to be comfortable in confrontational environments, and if the case goes to court, they must be confident enough to stand up to cross examination. With legal processes often being lengthy affairs, an expert witness must also have plenty of stamina and grit to keep going, even when the process becomes painfully drawn out.

Not only that but legal and court processes are very prescriptive, requiring specific information to be provided at the relevant times and in a particular way. An expert witness with a thorough understanding and experience of the legal process will be able to carry out their work more efficiently than someone with little to no understanding of the legal process.

The same goes for negotiating a settlement – an expert witness with an understanding of the negotiation process will be far more useful, and likely help achieve a much better outcome, than someone new to the game.

Adherence to the Code of Conduct for Expert Witnesses

Anyone who acts as an expert witness in New Zealand courts has a duty to read and comply with the Code of Conduct for Expert Witnesses. An experienced expert witness will be familiar with the Code, along with any specific requirements of the Court in which they are giving evidence.

In a broad sense, the Code states the expert witness must act impartially to assist the court (not advocate for any party to the proceedings). They must state their qualifications and confirm the issues they’re addressing are within their scope of experience (and any issues that are not). They must state the reasons for their opinions, and specify the evidence they relied upon, including any facts and assumptions, qualifying their evidence as necessary. They also have a duty to confer with another expert witness and try to reach agreement, as directed by the court.

There is no substitute for experience when it comes to acting as an expert witness – experience in a relevant professional discipline, but also experience acting as an expert witness in the past. Prendos has one of the country’s largest and most experienced teams of senior experts across multiple disciplines related to property and construction. So if you need an expert witness in a future case, we will very likely have an expert on our staff who can help.


Rory Crosbie is a Chartered and Registered Building Surveyor and Quantity Surveyor, as well as a Director, Deputy Board Chair and South Island Regional Manager at nationwide property and construction consultancy Prendos.

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