The idea is seductive: a derelict house is not really a "dwelling", so it should pay non-residential stamp duty — often tens of thousands less. Since the Court of Appeal's decision in Mudan v HMRC, that argument fails far more often than it succeeds, and HMRC now rejects the overwhelming majority of claims. This guide sets out the test as it stands, the narrow conditions that still qualify, how a refund claim actually runs, and the investigation risks that follow a claim made on hope rather than evidence.
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The Uninhabitable Property Argument After Mudan
SDLT charges residential rates on anything "suitable for use as a dwelling" under section 116 of the Finance Act 2003, and non-residential rates — with no 5% surcharge and a lower top band — on everything else. For years, refund agents pitched dereliction as a reclassification route. The Court of Appeal's judgment in Mudan narrowed the doorway to almost nothing: a run-down house is still a house.
HMRC's own estimate, cited when the Mudan litigation concluded, is that around 95% of uninhabitable-property claims do not qualify. The claims that survive involve genuine structural failure or hazards requiring deconstruction — not missing kitchens, dead boilers or damp. Read the criteria before the calculator.
What Counts as Uninhabitable for SDLT
The Two-Stage Test
The courts ask two questions. Was the building designed or adapted as a dwelling, with a residential history? And if so, has it lost the fundamental characteristics of a dwelling — not merely its comfort, but its essential structure and identity? A property can fail every habitability standard a tenant would apply and still pass the SDLT test comfortably, because "suitable for use as a dwelling" measures what the building is, not whether you would sleep in it tonight.
Mudan v HMRC: The Case That Closed the Door
In Mudan v HMRC [2025] EWCA Civ 799 the Court of Appeal considered a London house needing complete rewiring, new plumbing, a new boiler and substantial repairs — genuinely unlivable on completion day. The court held it remained residential: renovation works, however extensive, do not strip a structurally sound house of its character as a dwelling.
Key Principles from the Judgment
Suitability is not the same as immediate habitability; the question is whether the building has lost its fundamental residential characteristics. Works a renovator would simply schedule — wiring, plumbing, heating, windows, kitchens — are repairs to a dwelling, not evidence there is no dwelling. The judgment is binding, and it is the lens HMRC now applies to every claim.
HMRC's Criteria in Practice
HMRC's published guidance at SDLTM00385 tracks the case law and sorts conditions into two lists — and the first list is where nearly every hopeful claim dies.
Conditions That Do Not Qualify
- Kitchen or bathroom removed or unusable.
- Substantial repairs needed to windows, floors or the roof.
- No working boiler, heating or hot water.
- Unsafe or condemned electrical wiring.
- Utilities disconnected.
- Severe damp, mould or pest infestation.
- Fire or flood damage that leaves the structure standing.
What May Still Qualify
- Structural failure or imminent collapse — the building itself, not its systems.
- Asbestos or contamination at a level requiring deconstruction rather than treatment.
- Radioactive or comparable contamination.
- A Local Authority prohibition notice barring residential use.
- The tribunal-level successes (such as Davis & Guilbert, TC/2022/11605) combine several of these with contemporaneous expert evidence.
Claiming a Refund
Rates Compared
Residential vs Non-Residential Rates
| Consideration | Residential | With 5% Surcharge | Non-Residential |
|---|---|---|---|
| Up to £125,000 | 0% | 5% | 0% (to £150,000) |
| £125,001 – £250,000 | 2% | 7% | 1% – 2% by band |
| £250,001 – £925,000 | 5% | 10% | 5% above £250,000 |
| £925,001 – £1.5m | 10% | 15% | 5% |
| Above £1.5m | 12% | 17% | 5% |
The arithmetic explains the temptation: on a £1 million second property the gap between surcharged residential rates and non-residential rates runs to roughly £34,000. The size of the prize is exactly why HMRC polices the doorway.
Submitting the Claim
- Deadline: within 4 years of the transaction's effective date, by post to BT Stamp Duty Land Tax, HM Revenue and Customs, BX9 1HD.
- Structural engineer's report addressing the Mudan test, not just defects.
- Specialist surveys for contamination or asbestos where relied on.
- Dated photographs from at or near completion.
- Any Local Authority notices.
- The original SDLT return and transaction reference.
Investigation Risks and Penalties
A refund claim is a tax filing, and it carries a tax filing's consequences. HMRC has nine months to open an enquiry, four years to assess — twenty where fraud is suspected — and a penalty range running from 0% to 100% of the tax, plus interest from the original due date. The taxpayer, not the refund agent, carries all of it; the agents who solicit these claims are conspicuously absent once an enquiry letter arrives, a pattern HMRC has warned about publicly.
Red Flags That Attract Scrutiny
Evidence of recent occupation; planning applications for demolition or rebuild that undercut the "dwelling lost" story; claims that conveniently land near rate thresholds; submissions from volume refund agents; and thin documentation assembled after the event. A genuine claim survives scrutiny because its evidence predates the claim — everything else is an invitation.
Buying a Wreck? Do This Before Completion
If a property might genuinely qualify, commission the structural survey and take the classification decision before completion, filing the SDLT return on the right basis from day one. Contemporaneous expert evidence is what wins these arguments; a refund claim built months later on estate agent photographs is what loses them. And if the honest answer is "renovation project", pay residential rates and spend the professional fees on the renovation.
Questions about uninhabitable property and SDLT
What makes a property uninhabitable for stamp duty?
Structural failure, contamination requiring deconstruction, or a prohibition notice — conditions that strip the building of its character as a dwelling. Missing kitchens, dead heating, bad wiring and damp do not qualify, however unlivable they make the house in practice.
What did Mudan v HMRC decide?
The Court of Appeal held that a house needing complete rewiring, plumbing and heating remained "suitable for use as a dwelling" — suitability is about the building's fundamental character, not whether you could move in today. It is now the controlling authority on every claim.
How much could a successful claim save?
Materially — around £34,000 on a £1 million additional property, because non-residential rates avoid both the surcharge and the higher top bands. That prize is precisely why HMRC rejects the overwhelming majority of claims and investigates optimistic ones.
How do I claim an SDLT refund for an uninhabitable property?
By post to HMRC's BX9 1HD address within four years of the transaction, with the original return details and evidence built for the legal test: structural engineer's report, specialist surveys, dated photographs and any council notices. Evidence from before completion carries the weight.
What happens if HMRC rejects or investigates my claim?
Repayment of the tax with interest, penalties of up to 100% depending on culpability, and criminal exposure in fraud cases. HMRC has nine months to open an enquiry and four years to assess — and the liability is yours, not your refund agent's.
Should I use a no-win-no-fee SDLT refund agent?
HMRC has warned against the volume operators in this space: the taxpayer signs the claim, keeps the risk, and commonly finds the agent gone when the enquiry opens. If a claim is genuinely arguable, it deserves advice that will still be there in month nine.
Tell us the property's condition, what the surveys say and whether you have completed. We will tell you honestly whether the Mudan test is arguable, and build the evidence properly if it is.
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