Leaky Building Remediation and Tax: What Inland Revenue’s Updated Guidance Means for Property Owners in New Zealand.

Most property owners approaching leaky building remediation ask the same question first: how much will it cost? Fewer ask whether that cost is deductible. Inland Revenue’s updated guidance published in March 2026 makes that second question unavoidable.

Interpretation statement IS 26/01 and its associated fact sheet IS 26/01 FS 2 confirm Inland Revenue’s position: major weathertightness remediation on leaky buildings will generally be treated as capital expenditure and therefore non-deductible for income tax purposes. This is not a new policy. It is a clarification — but one that brings greater certainty to an issue that has long affected property owners across New Zealand.

What makes remediation capital expenditure?

Under section DA 2(1) of the Income Tax Act 2007, expenditure that is capital in nature cannot be deducted against income. The question of whether a particular remediation project crosses that line is determined by a two-step analytical framework developed through New Zealand case law.

The first step is to identify the relevant asset — in most cases, the building as a whole. The second step is to assess the nature and extent of the work undertaken, and determine whether it amounts to a repair or a capital improvement.

Inland Revenue considers weathertightness remediation to fall on the capital side in many cases because the work typically does more than restore the asset to its prior condition. The critical indicators are whether the remediation corrects inherent design or construction defects, involves the substantial replacement of integral building components, or brings the building up to modern standards. Where those factors are present, Inland Revenue’s view is that the work changes the character of the asset — and that expenditure is therefore capital.

What the courts have found

Recent court decisions reinforce Inland Revenue’s approach and provide further guidance on where the line falls.

In Lawrence v Commissioner of Inland Revenue [2024] NZHC 905, the High Court considered extensive weathertightness remediation on a rental property in Tauranga. The work involved substantial reconstruction to correct original design defects. The court found the expenditure went beyond repair and was treated as capital and non-deductible.

Separate decisions of the Taxation Review Authority have reached the same conclusion, confirming that remediation addressing inherent leaky-building defects generally falls outside the scope of deductible revenue expenditure.

Taken together, these decisions make clear that courts will examine the substance and extent of remediation works closely — not simply accept characterisations from the parties.

Why scope documentation now matters more than ever

One practical consequence of this guidance is that the scope of a remediation project carries direct financial implications, not just technical ones.

Property owners and body corporates who proceed without understanding the tax character of their proposed works risk making incorrect assumptions about deductibility. Those assumptions can affect financial planning, cashflow, and the treatment of costs in financial accounts. qually, if Inland Revenue scrutinises a remediation project, it will look at the substance of what was done — what was replaced, what defects were addressed, and what the works achieved relative to the building’s prior state. That examination will be based on documentary evidence: scope of works, specifications, variation records, inspection reports, and payment claims. Where documentation is incomplete or imprecise, the risk of an adverse determination increases. This is not a reason to avoid remediation. New Zealand buildings with weathertightness failures require remediation regardless of their tax treatment. But it is a reason to approach the process methodically — beginning with a thorough investigation, followed by a clearly scoped design, a well-structured contract, and rigorous independent oversight throughout.

The building and the liability do not wait

There is a separate and equally serious risk that this guidance does not address: the liability that attaches to inadequate remediation. The High Court decision in Keys and Others v Patterson and Others [2025] NZHC 2676 is a useful reminder. A recladding carried out in 2013 to 2014 failed to address root causes and left decayed framing in situ. By 2022, new owners were in court over defects arising from that earlier work. Claims exceeded $1 million. The original remediation did not resolve the liability. It deferred it.

Both the tax position and the legal exposure point in the same direction: remediation must be done correctly, in sequence, and with proper technical and contractual controls.

What property owners and body corporates should do

Owners undertaking or planning remediation projects should not assume that costs are automatically deductible because the work was necessary. In most significant leaky-building cases, those costs are treated as capital expenditure.

The steps that reduce both tax and legal risk are the same:

  1. Investigate thoroughly before designing. Root causes must be identified, not assumed.
  2. Scope clearly and document precisely. The scope of works is now a financial document as well as a technical one.
  3. Seek tax advice early — before works begin, not after completion.
  4. Use a properly structured contract that allocates risk clearly and defines the scope with precision.
  5. Monitor works independently throughout, including workmanship quality, variations, and progress.

Conclusion

Inland Revenue’s updated guidance does not change the nature of leaky buildings, or the obligation to remediate them. What it does is remove ambiguity about the financial consequences of that remediation, and reinforce that the scope, documentation, and substance of works will be examined closely.

Property owners who approach remediation with the same rigour they apply to other major asset decisions — clear scoping, proper contracts, independent oversight, and professional advice sought early — are best positioned technically, commercially, and now, fiscally.

A remediation project that is well-investigated, well-designed, and well-managed does not just fix the building. It protects the asset, the balance sheet, and the decisions that follow.

Aamsko provides weathertightness investigations, remediation design, construction law advice, independent project management, and cost management services for leaky building and remediation projects across New Zealand.