SDLT On Mouldy Or Water‑Damaged Homes: Habitable Or Not?
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Does a mouldy or water-damaged property count as uninhabitable for SDLT?
Introduction
Buyers often ask whether a property in poor condition can avoid residential Stamp Duty Land Tax treatment on the basis that it was not suitable for use as a dwelling at the effective date of the transaction. This question commonly comes up where a house has damp, mould, water ingress, disrepair, or plans for major renovation.
The difficulty is that the legal test is stricter than many people expect. A property does not become non-residential simply because it needs work, looks run down, or cannot comfortably be occupied without repairs. In recent cases, the courts have made clear that the threshold for showing a dwelling was not suitable for use is now relatively high, especially following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799.
The Question
A buyer was considering the purchase of a house that was said to be in poor condition. The property had mould and water damage, and there were plans for substantial works after completion. Sales particulars and photographs were reviewed, along with information about proposed redevelopment and discussions with the local authority.
The practical question was whether the property could be treated as unsuitable for use as a dwelling for SDLT purposes, so that the higher residential rates would not apply. When it became clear that this argument was weak, the follow-up question was whether the buyer should instead submit the SDLT return in the usual way and, if necessary, seek time to pay from HMRC.
Nick’s Explanation
Nick’s view was that the buyer should first assess the condition carefully, but that on the material provided the property was unlikely to qualify as unsuitable for use as a dwelling.
In anonymised form, his key point was:
“Based on my review of the photographs and sales particulars, I do not believe it can be argued that the property is unsuitable for use as a dwelling. Therefore, it will be subject to the higher rate of stamp duty.”
He then explained the practical next step if funds were tight:
“The best approach is to file the stamp duty self-assessment return through the conveyancing solicitor. Once you have a unique transaction reference number, the taxpayer should contact HMRC. If there is an unforeseen circumstance where they do not have sufficient funds to pay the stamp duty, they can then enter into a time to pay arrangement.”
The later correspondence also confirmed that, on the facts, the property was not so dilapidated that an uninhabitable argument could realistically be maintained.
The Law
SDLT is charged under the Finance Act 2003. Whether a property is taxed as residential depends on whether it is “residential property” at the effective date of the transaction.
The starting point is section 116 Finance Act 2003. Broadly, land 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.
The “unsuitable for use as a dwelling” issue usually arises where the buyer argues that, because of the property’s condition on completion, it was not residential property at all. If that argument succeeds, non-residential or mixed-use rates may apply instead of residential rates.
However, the case law has narrowed the circumstances in which a dwelling will be treated as unsuitable for use. The courts have distinguished between:
- a property that is genuinely incapable of functioning as a dwelling at the relevant date; and
- a property that is simply in poor repair, unpleasant, or in need of renovation.
The condition test is applied at the effective date of the transaction, usually completion. The question is not whether the buyer intends to redevelop, nor whether the property falls below modern expectations. The question is whether, viewed realistically, it is still suitable for use as a dwelling.
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.
Analysis
Applying those principles step by step:
The property was still a house and had been marketed as such. That is not decisive, but it is relevant evidence that the building retained the character of a dwelling.
The reported defects were mould, water damage, and general deterioration. Those matters can be serious, but they do not automatically mean that a building has ceased to be suitable for use as a dwelling.
The existence of a schedule of works, architect or surveyor drawings, and a plan for redevelopment does not itself help the SDLT argument. Many dwellings are bought for refurbishment or extension while still remaining residential property at completion.
The buyer’s own later acceptance that the property was “not so dilapidated” strongly points away from any viable claim that it was unsuitable for use as a dwelling.
On modern authority, the threshold is high. The property generally needs to be in a condition where it cannot realistically perform the function of a dwelling at all, not merely where occupation would be inconvenient, unhealthy, expensive, or undesirable without repairs.
If the property remained residential property, and the buyer already owned another dwelling without qualifying for replacement of a main residence treatment, the higher residential rates would apply in the normal way.
That is why Nick’s conclusion was that the safer position was to treat the purchase as subject to the higher rate of SDLT rather than pursue an uninhabitable argument on weak facts.
Outcome
A property with mould, damp, water damage, and planned renovation works will not usually fall outside residential SDLT treatment unless the condition is extreme. On the facts described, the property was unlikely to meet the legal test for being unsuitable for use as a dwelling.
The practical result was that the purchase should be treated as a residential acquisition, with the higher residential rates applying if the buyer’s wider SDLT position triggered them.
Practical Steps
If you are assessing whether a damaged property may be non-residential for SDLT purposes, the sensible steps are:
Focus on the condition at completion, not the buyer’s future plans.
Gather objective evidence, such as photographs, survey reports, contractor reports, and utility information.
Ask whether the building could still function as a dwelling in a real sense, even if only basically.
Be cautious about relying on damp, mould, outdated interiors, missing fittings, or the need for refurbishment alone.
Consider recent case law carefully, especially Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, because the courts now set a relatively demanding threshold.
If the transaction should be reported as residential, ensure the SDLT return is filed on time through the conveyancer.
If there is a genuine short-term funding problem, obtain the SDLT transaction reference and contact HMRC promptly to discuss whether a time to pay arrangement may be available.
Conclusion
Poor condition is not enough on its own to make a house non-residential for SDLT. Where the property is still recognisably capable of being used as a dwelling, even if it needs major work, the residential rules usually still apply. Following Mudan, the bar for showing a property was unsuitable for use as a dwelling is now high, so weak uninhabitable claims should be approached with care.
Legal References Used
- Finance Act 2003, section 116
- Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799
This page was last updated on 22 March 2026.
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