SDLT Treatment of Derelict and Uninhabitable Property Post‑Mudan
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Can you reclaim SDLT if a property was not suitable for use as a dwelling?
Introduction
Many buyers ask whether they paid too much Stamp Duty Land Tax (SDLT) because the property they bought was in such poor condition that it should not have been treated as residential. This issue usually arises where a house was structurally unsafe, had failed services, severe damp, subsidence, or needed major reconstruction before anyone could live there.
The question matters because a property that was genuinely “not suitable for use as a dwelling” at the effective date of the transaction may be taxed as non-residential rather than residential. That can produce a substantial SDLT refund. But the legal test is now strict, and recent case law has raised the threshold significantly.
The Question
A buyer purchased a house and later obtained evidence showing very serious defects at the date of purchase. The reported issues included structural movement, a failed ground floor slab, unsafe electrics, defective plumbing and drainage, widespread damp, and timber decay. The buyer and family lived elsewhere while substantial works were carried out, and the cost of the works was very high.
The buyer wants to know whether the property can be reclassified for SDLT purposes on the basis that it was not suitable for use as a dwelling when bought, and whether an SDLT refund claim is realistic.
Nick’s Explanation
Nick’s explanation was that the strength of any claim depends heavily on the legal test in force and the evidence available.
He explained that older cases had sometimes supported claims where a property was too dangerous to live in and needed more than ordinary repair or renovation. However, the position is now tighter. Following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, the condition thresholds in uninhabitable or not suitable for use cases are now relatively high.
In anonymised form, Nick’s view was that where evidence shows defects such as a failed slab, serious structural movement, unsafe electrics, full replacement of core services, and extensive damp and decay, there may still be an arguable case that the building had lost its fundamental characteristics as a dwelling. But he also stressed that HMRC are likely to challenge claims of this type, especially where the refund sought is substantial.
He also made two practical points:
- making the amendment or reclaim is often easier than defending the position if HMRC open an enquiry; and
- strong evidence is essential, including survey material, photographs, contractor documents, and professional statements showing the condition at the date of purchase.
Nick’s reasoning can be summarised like this: severe defects may support a claim, but only if they show more than a property in disrepair or in need of extensive renovation. The question is whether, at the relevant date, the building had ceased to be suitable for use as a dwelling under the now stricter test.
The Law
SDLT is charged under the Finance Act 2003. Whether property is residential or non-residential matters because different rates apply.
The key statutory provision is section 116 Finance Act 2003. Broadly, property is “residential property” if it consists of or includes a building that is used or suitable for use as a dwelling, or is in the process of being constructed or adapted for such use.
That means a building can still be residential even if it is vacant, dated, run down, or in need of repair. The legal question is not whether it is attractive, mortgageable, modern, or ready for immediate comfortable occupation. The question is whether it was suitable for use as a dwelling at the effective date of the transaction.
The case law has developed this test. Earlier authorities considered whether the building was so dangerous or defective that it could not properly be regarded as a dwelling. More recent decisions have narrowed the scope for taxpayers.
In particular, Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799 is now the leading authority on this point. In an uninhabitable or not suitable for use case, the condition thresholds are now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799.
The courts now focus closely on whether the property retained the fundamental characteristics of a dwelling. Serious disrepair alone is not enough if the defects are, in substance, repairable and the building remains recognisable as a house or flat capable of residential use after works are carried out.
Analysis
To analyse this kind of SDLT reclaim, it helps to work through the issue in stages.
First, identify the relevant date. The condition of the property must be assessed at the effective date of the transaction, usually completion. Later deterioration or later discoveries do not change the legal position unless they show what the condition already was on that date.
Second, separate serious disrepair from loss of dwelling status. A property may have:
- subsidence or structural cracking,
- unsafe electrics,
- obsolete plumbing or heating,
- damp and rot,
- damaged floors or ceilings, or
- a need for major strip-out and refurbishment.
Even taken together, those matters do not automatically make the property non-residential for SDLT. Many houses needing heavy renovation are still treated as dwellings.
Third, ask whether the building had lost its fundamental characteristics as a dwelling. This is where the modern authorities matter most. After Mudan, the threshold is high. The fact that a buyer chose not to live there, or that works were expensive, or that the property required extensive rebuilding, does not by itself answer the legal test. The real issue is whether the defects were so fundamental that the building was no longer suitable for use as a dwelling in law.
Fourth, consider the evidence. In the scenario described, the evidence appears stronger than in many failed claims because it points to a combination of core defects affecting structure, safety, and essential services:
- failure of the ground floor slab,
- widespread structural movement and subsidence,
- unsafe electrics requiring full replacement,
- obsolete or leaking plumbing and drainage,
- extensive damp and timber decay, and
- occupation elsewhere while major works were undertaken.
That combination may support an argument that the property was not merely tired or dilapidated, but had become unsafe and fundamentally defective.
Fifth, test that evidence against the post-Mudan standard. This is the difficult part. The Court of Appeal’s approach means HMRC will often argue that even severe defects are still defects capable of repair, and that the building remained a dwelling because it was still a house in substance. A full strip-out, a large budget, and a long programme of works may show severity, but HMRC may still say the property retained its essential residential character.
Sixth, consider procedure. A taxpayer may amend an SDLT return or make a reclaim within the applicable statutory time limit. But if HMRC disagree, they may refuse the claim or open an enquiry. In practice, that is often where the real dispute begins. A brief assertion that the property was uninhabitable is rarely enough. The taxpayer usually needs a coherent evidential package showing the exact condition at completion and why the defects crossed the legal threshold.
Seventh, note that evidence should be contemporaneous where possible. The most useful documents usually include:
- the pre-purchase survey,
- photographs and video from the time of purchase,
- engineer, architect, or surveyor evidence,
- schedules of works,
- contractor quotations and invoices,
- planning and building documents where relevant, and
- proof that the property could not safely be occupied at the time.
Documents created later can still help, but they are strongest where they clearly refer back to the property’s condition on the completion date.
Outcome
The practical conclusion is that a claim may be arguable where the evidence shows exceptionally serious defects affecting the structure, safety, and basic functioning of the building at the date of purchase. On the facts described, there appears to be a potentially credible argument for non-residential treatment.
However, readers should be careful not to assume that major renovation alone is enough. Following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, the threshold in uninhabitable or not suitable for use cases is now relatively high. HMRC are likely to scrutinise claims closely and may argue that even a very poor property remained a dwelling because the defects were ultimately repairable.
Practical Steps
If you are assessing whether you may have overpaid SDLT on a severely defective property, the sensible next steps are:
- Check the completion date and the time limit for amending the SDLT return or making a reclaim.
- Gather the best contemporaneous evidence of condition at the purchase date.
- Review whether the defects affected the property’s fundamental character as a dwelling, not just whether the works were expensive or extensive.
- Compare the facts carefully with the reasoning in Mudan and earlier authorities.
- Prepare a clear explanation linking the facts to section 116 Finance Act 2003.
- Be ready for HMRC to ask for further evidence or open an enquiry.
- Consider the financial risk, including repayment of any refund plus interest if HMRC ultimately succeed.
Where the case depends on structural failure, failed services, or major safety issues, professional evidence from a surveyor, engineer, or architect can be particularly important.
Conclusion
A property in very poor condition does not automatically qualify for non-residential SDLT rates. The question is whether, at completion, it was truly not suitable for use as a dwelling under section 116 Finance Act 2003. After Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, that is a demanding test. Strong factual evidence is essential, and only the most serious cases are likely to succeed.
Legal References Used
- Finance Act 2003, section 116
- Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799
- Mudan v HMRC [2025] EWCA Civ 799
- Bewley case
This page was last updated on 22 March 2026.
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