Does a former nursery outbuilding make a house mixed-use for SDLT?

Introduction

Buyers sometimes ask whether a house can be treated as mixed-use for Stamp Duty Land Tax because part of the property was used for a business in the past. A common example is an outbuilding that was once used as a nursery, office, clinic or workshop.

This matters because mixed-use purchases are taxed under the non-residential SDLT rates, which can be much lower than the residential rates on higher-value purchases. The key question is not simply whether there was a business use at some point. The real issue is what is being bought at the effective date of the transaction and whether any part of the property is genuinely non-residential at that time.

The Question

A buyer is considering purchasing a detached dwelling for around £1.3 million. The property includes a separate outbuilding. The sellers previously used that outbuilding as a nursery several years ago, and there are still signs of that former use, such as markings on the floor and historic regulatory records. The buyer wants to know whether this is a straightforward mixed-use case so that lower SDLT rates would apply.

Nick’s Explanation

Nick’s view, in anonymised form, was that this is not a cut-and-dried mixed-use case merely because the outbuilding was once used as a nursery. The important point is the present character and use of the property at completion, not just its history.

In substance, his reasoning can be summarised like this:

• Past commercial use on its own is usually not enough.
• The question is whether part of the property is non-residential at the time of purchase.
• If the outbuilding has reverted to use that is ancillary to the dwelling, HMRC is likely to treat the whole purchase as residential.
• Historic evidence such as old floor markings or previous inspection reports may show what used to happen there, but they do not by themselves prove mixed-use status for SDLT.

That is broadly consistent with the way HMRC and the tribunals approach these cases. SDLT classification depends on the legal and factual position at the effective date of the transaction.

The Law

SDLT is charged under the Finance Act 2003. Whether a purchase is taxed as residential, non-residential, or mixed-use depends on the definition of “residential property” in section 116 Finance Act 2003 and the charging provisions that apply to the transaction.

Broadly:

• Residential rates apply if the subject matter consists entirely of residential property.
• Non-residential rates apply if the property is wholly non-residential, or if the transaction is mixed-use.
• A mixed-use transaction is one involving both residential and non-residential property.

Section 116 Finance Act 2003 treats property as residential if it consists of:

• a building used or suitable for use as a dwelling, or in the process of being constructed or adapted for such use, and
• land that is or forms part of the garden or grounds of that dwelling, including any interest or right over that land.

That means an outbuilding within the garden or grounds of a house will often still fall within the residential classification if it is part of the dwelling’s overall residential setting and function, even if it had a different use in the past.

In addition, where buyers argue that a building is not residential because it is not suitable for use as a dwelling, the courts have taken a relatively strict approach. In uninhabitable or not suitable for use cases, the threshold is now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799.

Analysis

The safest way to analyse this kind of case is to work through the facts in stages.

1. Identify what is being bought

   If the buyer is acquiring a house together with its land and a separate outbuilding, the starting point is that the whole property is residential unless some identifiable part is non-residential.

2. Ask what the outbuilding is used for at the effective date

   If the outbuilding is currently being used for a commercial activity under a real and continuing business use, that may support mixed-use treatment. But if the commercial activity ended years ago and the building is now simply part of the property, the historic use may carry little weight.

3. Consider whether the outbuilding is ancillary to the dwelling

   An outbuilding used for storage, hobbies, family activities, home working incidental to domestic occupation, or general residential purposes will usually be regarded as part of the dwelling or its grounds. In that case, the purchase is likely to remain residential.

4. Look at objective evidence, not just old traces of use

   Old nursery markings, past planning history, or archived inspection material may show that the building was once used for a business. But SDLT turns on the legal and factual status at completion. Evidence that would be more persuasive includes current planning status, an active lease or licence, business rates treatment, current commercial occupation, separate access and facilities, and actual non-residential use continuing at the transaction date.

5. Check whether any argument is really an “unsuitable for use” argument

   Sometimes buyers try to argue that part of the property is not residential because it is not suitable for use as a dwelling. That is a different point. Following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, the condition threshold is relatively high. Ordinary disrepair, unusual layout, or the need for works will often not be enough.

Applying those steps here, the fact that the outbuilding was used as a nursery until a few years ago does not automatically make the purchase mixed-use. If that use has ceased and the outbuilding now simply forms part of the house and its grounds, HMRC would be likely to argue that the whole property is residential.

The position may be different if, at completion, the outbuilding is still genuinely set up and used as a separate commercial unit, or if there is some other clear non-residential element to the land or buildings being acquired. But on the facts described, this does not sound like an obvious mixed-use case.

Outcome

A former nursery outbuilding does not, by itself, make a house mixed-use for SDLT. Historic business use is not enough. What matters is whether part of the property is non-residential at the time of purchase. If the outbuilding has reverted to being part of the dwelling and its grounds, the transaction is likely to be treated as residential and taxed at residential SDLT rates.

Practical Steps

• Check the actual use of the outbuilding at the proposed completion date.
• Review planning permissions, lawful use evidence, and any conditions affecting the outbuilding.
• Establish whether there is any current commercial occupation, lease, licence, or business rates assessment.
• Consider whether the outbuilding is functionally separate or merely ancillary to the house.
• Ask the conveyancer to confirm the SDLT filing position on the basis of present facts, not historic use alone.
• If mixed-use is being considered, gather objective evidence showing a genuine non-residential element at completion.
• If any argument depends on the building being uninhabitable or unsuitable for use, assess it carefully in light of Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, because the threshold is now relatively high.

Conclusion

The short answer is no: a previous nursery use does not make the SDLT position “cut and dry” in favour of mixed-use. For SDLT, the present character and use of the property are critical. In many cases like this, the purchase will still be residential unless there is a real and current non-residential element at completion.

Legal References Used

• Finance Act 2003
• 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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