Buyer beware: due diligence is key to preventing building defects

June 3, 2025
Buyer beware due diligence is key to preventing building defects by Heather Crilly and Ivan McLellan

Chartered and Registered Building Surveyor Heather Crilly, and Registered Building Surveyor Ivan McLellan, have significant experience inspecting and diagnosing defective new builds. We spoke with them about the sort of building defects they’re commonly seeing in New Zealand new builds, and what homeowners can do to protect themselves from having to foot the bill for costly repairs.

Building defects – also called construction defects – occur when part of a building does not perform as required. While some defects like badly installed cabinetry or paint finishes that aren’t up to scratch can impact the appearance and amenity of your home, others like weathertightness issues can result in serious damage to the building’s structure and fabric over time.

Ivan says in many cases, water ingress is the first sign of a problem for homeowners. But that can be just the tip of the iceberg.

“In many cases, if there’s water leaking inside the building, it makes the owner wonder what else the builder might have done wrong,” Ivan says. “Either that or they’ve had problems throughout the build, and they’re not entirely happy with the way they’ve been sorted, so they want an expert to have a look before they make the final payment. But of course by then the damage is usually done.”

Building defects aren’t limited to any particular type or value of new build either. Both Heather and Ivan say they’ve recently investigated building defects in a variety of building types, from high end architecturally designed homes to group home builds, and from heritage villa extensions to brand new multi-unit apartment blocks.

What they do tend to have in common, says Heather, is the sheer number of issues to be found once a trained and experienced eye starts peeling back the layers.

“Most of what I’m seeing is residential new builds with a myriad of things done wrong from the framing up, which just multiplies as you go on,” Heather says. “Very little has been done in line with the manufacturer’s installation guidelines. It’s either sloppy work, or just not as per the specification in the consented plans.”

Ivan points out that problems can originate from the drawing board too, with design issues not picked up during the consent process, or questioned by the builder, becoming major headaches for the homeowner.

“A house I went to recently had a badly designed window,” Ivan says, “but nobody involved in the entire process picked it up, even though it was obvious that it would leak. Nobody thought maybe this isn’t going to work, we should do it differently. They just built it as per the design and it leaked.”

Heather believes there’s often a strong drive once the build is underway to just ‘get the job done’. The Kiwi ‘can do’ attitude, while honourable in its intent, can result in an unwillingness to highlight issues that will delay the project and incur more cost through redesign and consenting. That leads to problems being overlooked rather than dealt with.

Relying on council inspectors to identify issues is another trap that homeowners can fall into, Heather says. Aside from the fact that councils are primarily responsible for ensuring compliance with the Building Code, and not necessarily functionality or workmanship, councils are also tasked with a complex job, often without the necessary resources.

“There’s very much a reliance on council, but it’s not down to them to check everything,” says Heather. “They only have certain stages for inspection and all they’re principally concerned about is whether it meets code. They’re not there to check whether things are aesthetically right or meet the homeowner’s requirements.”

So if homeowners can’t rely on council inspections to prevent every type of building defect, what else can they do?

For both Heather and Ivan, it comes down to having the right builder, combined with effective site supervision. They stress that checking references is one of the best ways to establish if a builder has a good reputation, or a string of defective builds behind them.

“Problems are really difficult to avoid when you’ve got the wrong builder,” says Heather. “Generally a bad builder will be bad on pretty much all projects they work on in my experience. So talk to as many different people as possible that they’ve done work for, and ask what their experience was.”

Good site supervision is absolutely critical too. Having been in the construction industry for over 40 years, Ivan believes much of today’s defective construction has resulted from the specialisation of the building process into multiple sub-trades, without effective supervision to tie them together.

“Back in the day you learned to build an entire house by yourself, but now someone comes and does the foundations, another person puts up the kitset wall frames and roof trusses, and there are specialists just for the cladding,” Ivan explains. “The junctions where each one of these sub-trades meet is where you get problems, because each subbie says ‘that’s not my job’. You need a qualified supervisor spending enough time on site to check that everything is done right.”

“If you get some good feedback on the builder you want to choose, that’s a good start,” says Ivan. “But even with a good builder, if they’re building three houses at once rather than just one, and they’re not on site all the time, problems can happen. So the best option is to have another party act as an independent overseer.”

For most people though, an independent site supervisor means another chunk of money they hadn’t banked on spending. So again it comes down to doing your due diligence, checking references, and making sure your builder has a plan in place for effective site supervision throughout the build.

“It’s an issue I see with some group home new builds,” says Ivan. “They have site managers and supervisors that run around keeping an eye on several houses at once, so you’re still not getting that consistent supervision on site. I’ve also heard of one build where they went through three different supervisors.”

Unfortunately for the homeowner, they often find themselves between a rock and a hard place when things do go wrong. Residential building contracts are usually skewed in favour of the builder, says Heather. Pressure can be put on the client to accept ‘practical completion’ and hand over the final payment before defects are remedied, so they can get the keys and move in. The ongoing cost and availability of temporary accommodation is often the deciding factor in how firmly the owner can stand their ground.

Homeowners who go down the path of pursuing litigation have a difficult choice too. Do they go after the builder, the designer, the council – and at what cost?

“If the builder has no money, or can’t be found, then the only option may be to pursue the council,” says Ivan. “But there’s a big cost to pursuing it in court.”

Whether homeowners decide to pursue a claim for building defects in court or through alternative dispute resolution, the critical thing they should do is to document as much as possible, says Ivan. The process of gathering facts to support the claim must be well recorded to increase the chances of a payout or contribution from the defendants, whether the architect, builder or council. That’s where the help of a qualified and experience Building Surveyor is invaluable, as they can forensically investigate and provide evidence and expert testimony to aid dispute resolution.

Ultimately when it comes to probably the biggest purchase many people will make in their lifetime, it’s a case of buyer beware. Checking references, and getting comparative quotes, is an essential part of the due diligence process. If one quote is significantly cheaper than the others, says Heather, it could be a red flag.

Factoring in appropriate contingencies is also important, because on-site issues are inevitable, no matter how straightforward the build. If there’s money set aside to cover the cost of essential variations, it’s less likely those issues will be quietly brushed under the carpet, only to rear their ugly head at a later date.

While the current trend in New Zealand seems to be deregulation of the construction industry, it does seem there are major gaps in the legislation as it is. Rather than relying on regulations to keep them safe from building defects, homeowners who want to ensure the durability and value of their asset would be well advised to do as much due diligence as possible before signing on the dotted line of any construction contract.

If you are concerned about construction defects, our nationwide team of Chartered and Registered Building Surveyors provide independent building defect investigation and testing services, advice on remediation, and expert testimony to support legal claims. Call 0800 PRENDOS or email prendos@prendos.co.nz to speak with one of our team.