The renovated kitchen looks fantastic. The extra bedroom is exactly what your family needs. The converted garage has real potential as a home office. Before investing, ask yourself: was this work properly consented?
Unpermitted building work is far more common in New Zealand homes than most buyers realise. Industry estimates suggest roughly one in five properties contains some form of unconsented work. It’s a problem that spans every region, from Auckland villas with decades of accumulated additions to Canterbury homes patched up hurriedly after the earthquakes to Wellington properties perched on hillsides with retaining walls of questionable origin. Knowing how to spot the warning signs before you commit is one of the most valuable skills a property buyer can develop.
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Why Unconsented Work Is So Widespread
The reasons are varied, and it’s not always deliberate rule-breaking. Many homeowners simply don’t understand when building consent is required. A bathroom renovation seems straightforward enough — why would you need council involved? A deck off the back of the house feels like a weekend project, not a regulatory matter.
Other common scenarios include DIY renovations that gradually expanded beyond their original scope, garage or sleepout conversions completed without anyone checking what the rules required, additions done by previous owners who have long since moved on, and work carried out decades ago when record-keeping was far less rigorous than it is today.
In regions that experienced natural disasters — Canterbury’s earthquakes being the most obvious example — the pressure to repair homes quickly also created fertile ground for shortcuts. But the issue isn’t confined to any single city or event. It’s a nationwide problem rooted in a combination of a can-do DIY culture, genuine ignorance of the rules, and, occasionally, deliberate avoidance of the cost and hassle of the consent process.
What Actually Requires Building Consent?
Under the Building Act 2004, most building work in New Zealand requires consent from the local territorial authority. This covers structural changes, plumbing and drainage modifications, electrical work beyond minor repairs, and anything affecting the building envelope’s weathertightness.
In practical terms, that means consent is typically required for adding or removing walls, building decks above a certain height, installing new bathrooms or kitchens, adding windows or doors to external walls, converting a garage into a habitable room, building a sleepout or minor dwelling, installing a wood burner, and constructing significant retaining walls.
Some minor work is exempt under Schedule 1 of the Building Act, but the exemptions are subject to specific conditions. The fact that something seems simple doesn’t automatically mean it’s exempt. Many homeowners get caught up in this distinction.
Warning Signs to Watch for During Viewings
You don’t need to be a building inspector to pick up on some of the more obvious red flags. Training yourself to look for certain visual cues during property viewings can help you identify potential consent issues early.
Inside the property, watch for inconsistent flooring between rooms — different levels, materials that don’t quite meet at doorways, or tiles that are slightly misaligned at transitions. These can suggest that walls were moved or spaces reconfigured. Ceiling heights that vary from one part of the house to another deserve attention, too, as they may indicate a converted attic space or work done without proper engineering input.
Electrical outlets or light switches in unusual positions, along with multiple power boards daisy-chained together, can point to DIY electrical work. Plumbing that looks like an afterthought — exposed pipes running along walls, awkward bathroom layouts, or drains that gurgle — may indicate work done without consent or proper inspection.
On the outside, look at extensions and additions critically. Does the new section match the original house in terms of materials, roofline, and architectural style? Professionally consented work typically blends more seamlessly. Sleepouts, converted garages, and granny flats are particularly high-risk areas — these additions frequently lack proper consents, especially when they include plumbing or have been set up as independent living spaces.
Pay attention to retaining walls, especially taller ones that should have an engineering sign-off. Walls that lean, show significant cracking, or appear to lack proper drainage behind them are concerning. Decks and pergolas above a certain height, or attached to the house, often require consent as well, and signs of rough construction can suggest they were owner-built without council involvement.
Documentation Red Flags
Sometimes the warning signs aren’t physical — they’re behavioural. If the vendor seems reluctant to discuss the property’s renovation history or deflects questions about specific improvements, ask yourself why. Most homeowners who’ve done legitimate renovations are happy to talk about them.
Marketing language can also be revealing. Phrases like “bonus room,” “versatile space,” or “potential income” without any mention of consent status should prompt further investigation. Properties listed “as is where is” sometimes carry that designation specifically because of unresolved consent issues.
How to Check Council Records
Every territorial authority in New Zealand maintains records of building consents and Code Compliance Certificates for properties within its district. Before making an offer — or as part of your due diligence conditions — you can check what’s on file.
The most comprehensive option is a Land Information Memorandum (LIM) report, which shows all building consents issued for the property along with any notices, requisitions, or compliance issues. A LIM costs several hundred dollars but provides a thorough paper trail.
For a quicker preliminary check, most councils offer online property search tools that show basic consent information. This won’t give you the full picture, but it can flag obvious discrepancies before you invest in a LIM.
The key exercise is to compare what’s documented with what you can physically see. A three-bedroom house where council records show only two bedrooms is an immediate red flag. A bathroom that doesn’t appear in any consent documentation warrants scrutiny. An entire ground-floor extension with no corresponding consent record is a serious concern.
The Consequences of Buying a Home with Unpermitted Work
The financial and practical implications can be significant. Insurance is often the first problem — many insurers will decline to cover unpermitted work or may exclude it from your policy entirely. Some won’t insure the entire property if significant unconsented work is present.
When you eventually come to sell, the issue becomes your problem to disclose. Future buyers and their solicitors will ask the same questions, and unresolved consent issues can derail a sale or significantly reduce the price a property achieves.
You may also face requirements to remediate or remove the unpermitted work, the cost of applying for retrospective consent through a Certificate of Acceptance, potential safety risks if the work doesn’t meet Building Code standards, and challenges with bank valuations and lending.
The Certificate of Acceptance Option
When unpermitted work is discovered, one option is to apply for a Certificate of Acceptance (COA). This is a retrospective process in which the council assesses work carried out without consent.
It’s important to understand what a COA is and isn’t. It doesn’t confirm that the work complies with the Building Code. It confirms only that the council has assessed the visible elements as far as reasonably practicable. Because the council can’t inspect what’s concealed behind walls or underground, a COA provides considerably less assurance than a standard Code Compliance Certificate.
The process requires an application with documentation, a council inspection, possible destructive testing or specialist reports, and fees that may reach several thousand dollars based on complexity. If the work clearly doesn’t meet code, a COA may not be available — in which case, you could be facing removal or significant modification of the non-compliant work.
Why a Pre-Purchase Inspection Matters
A professional pre-purchase building inspection is one of the strongest tools available for identifying potential consent issues before you’re committed. Experienced inspectors know what to look for — they can pick up on telltale signs of unpermitted work that casual buyers routinely miss.
During an inspection, a qualified inspector will assess whether visible work appears consistent with council records, look for signs of structural modifications, evaluate the quality and installation methods of plumbing and electrical work, identify evidence of converted spaces or additions, and flag general workmanship that suggests DIY rather than professional construction.
An inspector can’t definitively confirm whether work has consent — only council records can. But they can identify work that warrants further investigation and provide the information needed to negotiate with the vendor or to make your purchase conditional on a satisfactory resolution. For buyers in Christchurch and right across New Zealand, this layer of professional scrutiny is invaluable.
Questions to Put Directly to the Vendor
Don’t be shy about asking pointed questions. Vendors have an obligation to disclose known defects, and consent issues can constitute a defect. Useful questions include what renovation or building work has been done during their ownership, whether they have copies of building consents and Code Compliance Certificates, whether they’re aware of any work done by previous owners, and whether the property has ever been subject to council notices or compliance proceedings.
Straightforward answers are a good sign. Evasiveness or vague responses should prompt you to dig deeper.
Protecting Yourself in the Contract
Work with your solicitor to include appropriate conditions in your sale and purchase agreement. These might include a condition requiring verification that all building work has appropriate consents, requirements for the vendor to obtain a COA for specific work before settlement, price adjustments reflecting the cost of obtaining retrospective consent, or warranties from the vendor regarding the consent status of all work carried out.
Your solicitor can also review the title and existing documentation to identify consent-related issues before you’re contractually bound.
How to Spot Unpermitted Building Work Before You Buy a New Zealand Home
Unpermitted building work is one of the more common — and potentially expensive — pitfalls facing New Zealand property buyers. The good news is that it’s largely avoidable with proper due diligence.
Look for the visual warning signs during viewings. Check council records before you commit. Ask the vendor direct questions and pay attention to how they respond. And always get a thorough pre-purchase building inspection from someone who knows what they’re looking for.
A few hundred dollars spent on due diligence before settlement can prevent tens of thousands in remediation costs afterwards. When it comes to unpermitted building work, what you don’t know really can hurt you — and there’s no good reason to go in uninformed.
