The hidden cost of NSW building defects: why the real problem is bigger than the complaints

Quick answer: Residential building defects are a significant consumer issue in NSW, and official dispute numbers do not capture everyone who experiences them. NSW Fair Trading recorded 48,043 residential building complaints between 2016 and 2021. Separate 2025 research into a defined sample of NSW apartment buildings found serious defects in 53% of surveyed buildings, but only 36% of buildings with serious defects reported them to the regulator. Those statistics do not give a defect rate for newly built detached houses; they reveal a substantial documented problem and a significant reporting gap. Sources: NSW Parliament; Building Commission NSW.

The beautiful new home—and the risk nobody shows you

A newly completed house can look like the low-risk choice: modern finishes, fresh appliances, current construction standards, perhaps a pool and an occupation certificate. The real estate agent describes the building as complete. The seller's contract contains a thick package of legal documents. The buyer assumes any serious construction problem will be fixed by the developer or insured.

Now imagine finding water damage behind a wall after settlement. The buyer obtains an engineer's report and a quotation for major waterproofing repairs. The developer says the builder is responsible; the builder questions its scope of work; the entity that sold the home was a project-specific company with few remaining assets. The insurer may not respond simply because a builder refuses to repair something. The buyer faces the cost of experts, negotiations and potentially tribunal proceedings—before anyone fixes the leak.

That is a hypothetical scenario, not an allegation against a named developer. Each element, however, is a real category of legal or commercial risk. The uncomfortable question is not only “Could the house have defects?” It is “If it does, who will pay, and can I actually make them pay?”

How big is the NSW problem?

Three different sources describe three different layers of the system:

Sources: NSW Parliament; NCAT Annual Report 2024–25, table 3; Building Commission NSW 2025 research.

These numbers cannot be added together. Their categories overlap, periods differ, and some data concerns apartments while other data covers all sorts of residential building work. Their value is in showing scale, different stages of escalation, and incomplete visibility.

The iceberg: reported disputes are the visible part

Think about 100 surveyed apartment buildings already known to have serious defects. Based on the 2025 reporting proportion, approximately 36 would have reported the defects to the regulator and 64 would not. This is a description of the survey's reporting result, not a projection to NSW houses.

Why might a serious defect go unreported? It could be resolved directly with the builder or owners corporation. The owner might not know about reporting channels. There might be a confidential settlement. Or the owner might decide that the financial and personal costs of pursuing the matter outweigh the likely recovery. We cannot assign precise shares to these reasons from the 2025 headline figures.

A 2021 NSW Government release about an earlier strata survey specifically identified cost and lack of awareness as leading reasons serious defects were not reported. In that earlier survey, 15% of strata complexes with serious defects had reported them. NSW Government media release.

The iceberg therefore has several layers:

1. Defects reported to the regulator.
2. Disputes pursued privately with builders, developers or insurers.
3. Defects resolved through private repairs or informal arrangements.
4. Defects not yet discovered, including hidden or latent issues.

We have data for parts of the first two layers. We do not have a robust statewide count for all four layers, particularly for purchasers of newly built detached houses. The right conclusion is not a made-up total; it is that the official counts are an incomplete measurement of the underlying problem.

Why someone might pay for a defect rather than chase the builder

Take an illustrative $7,000 waterproofing repair. A homeowner could spend money on reports, correspondence, legal advice and time off work to dispute responsibility. They might win—or they might receive a repair order that requires further follow-up. Paying the repair bill themselves can become a rational choice even where they believe the builder is legally responsible.

IPART's 2020 review of the NSW Home Building Compensation Fund recognized the economic friction. It reported that NCAT disputes above $30,000 took almost nine months on average using data available in 2020, and that homeowners might incur several thousand or tens of thousands of dollars obtaining expert and legal advice. These are historical observations, not today's average fee for every building dispute. IPART review.

The contrast matters. A larger defect might justify a significant claim, while a smaller defect may never reach an official database. That selection effect means published tribunal cases are valuable for studying how things go wrong, but unreliable for calculating the average cost or probability of defects across all new homes.

The hidden problem behind the defect: accountability

Even if a leak or structural fault is proven, a homeowner may still confront separate questions:

• Which legal entity developed and sold the property?
• Which licensed contractor completed the affected work?
• Were different works performed by different contractors?
• Does a statutory warranty benefit this particular purchaser?
• Is the responsible company solvent and capable of performing repairs?
• Does the Home Building Compensation policy respond to the circumstances, and how much would it pay?
• Do the occupation certificate and development consent demonstrate that all relevant works were approved and completed?

A company that exists only for one project—usually called a special-purpose vehicle (SPV)—is not necessarily suspicious. Such structures can be legitimate commercial arrangements. The risk arises if the purchaser assumes a financially substantial development group is legally backing the property when the actual seller and responsible contractors are separate entities. Read our guide to developer SPVs and builder accountability.

What a building certificate and insurance policy really mean

Occupation certificate: an occupation certificate is meaningful regulatory evidence that the relevant building or part of a building met the requirements for its issue. It is not a guarantee against every hidden defect or proof that every development condition is complete. NSW permits partial occupation certificates for staged work. Service NSW. See occupation certificates and DA compliance.

Home Building Compensation cover: for eligible work, HBC insurance is generally a last-resort protection triggered by specified circumstances such as builder insolvency, death, disappearance or a qualifying licence suspension—not a general policy that pays whenever the builder argues. SIRA explains that the minimum combined cover is $340,000 for eligible claims, subject to terms and rules. SIRA scheme overview; SIRA product limits. See what insurance covers.

Pool certificate: NSW allows many properties with a swimming pool to be sold with a valid certificate of non-compliance. The buyer can inherit an obligation to remedy the listed issues after settlement, normally within 90 days unless a significant public-safety risk is identified. NSW Government. See pool certificate risks.

Five distinct costs buyers can inherit

Repairs: waterproofing, drainage, structural remediation and replacement of defective components.

Investigation: engineering, building, waterproofing, planning and surveying reports needed to identify defects and establish liability.

Compliance: remedying unauthorized or non-compliant works, providing required certificates or addressing outstanding development conditions. The question of who ultimately pays is case-specific.

Enforcement: negotiations, legal advice, tribunal proceedings and potentially enforcing a judgment.

Consequences: temporary accommodation, lost rent, financing costs, resale delays and disruption. Not all of these costs are legally recoverable in every case.

The purchase price is not a proxy for the amount of insurance coverage or the financial strength of the contracting party.

What should buyers do before paying the deposit or exchanging contracts?

Begin with the seller's exact legal name, the builder's licence, the HBC certificate and its insured scope, the approved plans, development consent and modifications, the occupation certificate's precise scope, pool certificate, council records and a comprehensive independent building inspection. For a developer-built house, ask for construction and completion documentation that helps establish who performed key work and when.

If anything is unclear, identify what cannot be verified and obtain specialist advice before committing. A standard visual building inspection is valuable but it usually cannot establish hidden waterproofing quality, complete planning compliance or the financial capacity of a seller. Our full new-build due diligence checklist prioritizes these steps.

What does the evidence actually justify saying?

We can credibly say that the residential building dispute problem is substantial, that serious defects in surveyed apartment buildings are frequently not reported to the regulator, and that rights, insurance and enforcement do not guarantee an easy financial recovery.

We cannot credibly say that 53% of detached new-build homes have serious defects, that 64% of house buyers pay privately, or that a particular percentage of developers use SPVs to escape claims. Those are separate empirical questions requiring separate evidence.

Our detailed companion article explains what can be measured, why popular statistics are often misused, how disputes can be coded and which risk factors need case-by-case verification: The evidence and causes behind NSW building defect disputes.

Frequently asked questions

Are building defects common in NSW?

There is significant evidence of residential building complaints and serious defects in surveyed NSW apartment buildings. There is no reliable public defect-prevalence figure for all newly built detached houses sold to purchasers. Avoid applying apartment survey rates to houses.

How many NSW home buyers discover defects and never complain?

The exact number is unknown. The 2025 strata survey found that 64% of buildings identified with serious defects had not reported them to the regulator. That is evidence of underreporting within the surveyed apartment population, not a statewide estimate of silent house buyers.

Can a developer legally sell through an SPV?

Yes. An SPV is a legitimate company structure. Buyers should verify which entity owes which obligations and whether any contractual guarantee, insurance or other protection stands behind those obligations.

Does an occupation certificate guarantee a defect-free home?

No. It permits occupation of the building or relevant part subject to statutory requirements; it does not certify that every concealed component is defect-free. Check the scope, approvals and outstanding conditions.

Does home building insurance pay if the builder refuses to repair a defect?

Generally not just for refusal. NSW HBC cover is principally a last-resort scheme responding to defined events. Notify the insurer promptly and check the actual policy.

Can you win at NCAT and still not get paid?

Yes. An order establishes an obligation but may need further enforcement. NCAT explains how a certified money order can be registered with a court for enforcement. NCAT enforcement guidance.

What is the most important new-build purchase question?

Ask not only whether the property appears complete, but who is responsible if a defect appears, how that responsibility can be enforced, and what financial protection exists if that party cannot pay.

Continue reading

• Data investigation: size, causes, risk factors and research limitations
• SPVs, developers and builder accountability
• Home Building Compensation insurance
• Occupation certificates and DA compliance
• Pool compliance on purchase
• New-build due diligence checklist
• What to do when the builder refuses to fix a defect

Research note (31 October 2026): figures are attributed to their original years and source populations. This article is general information, not legal, engineering or insurance advice. Independent legal review is recommended before publication.