Can a flat with a shared gym be treated as non-residential for SDLT?

Introduction

Buyers sometimes ask whether a flat or apartment can be treated as non-residential or mixed-use for Stamp Duty Land Tax (SDLT) because the building includes shared facilities such as a gym, concierge area, shops, health space, or other communal amenities. This usually happens after a purchase has completed and the buyer is looking at whether too much SDLT was paid, or where an earlier claim has already been rejected by HMRC.

This is a difficult area. A shared gym in the block does not automatically make a dwelling non-residential. Equally, the fact that a property is a flat does not prevent a mixed-use argument if the legal and factual position genuinely supports it. The answer depends on what was actually bought, what rights came with it, and whether the transaction included land or property that was not residential in character.

The Question

A buyer acquired a high-value penthouse apartment in a residential block. The building includes a shared gym facility. A previous attempt to argue that the property was not suitable for use as a dwelling was rejected by HMRC. The buyer now wants to know whether the presence of the shared gym, or other non-residential features in the building, could mean the purchase should instead be treated as mixed-use or non-residential for SDLT purposes.

Nick’s Explanation

Nick’s view, in anonymised form, was that this kind of case is often too contentious to assess by headline features alone. The fact that a gym exists somewhere in the building is not enough by itself. The real question is whether the buyer acquired rights over property that can properly be characterised as non-residential, and whether those rights formed part of the chargeable interest acquired.

His reasoning can be summarised like this:

• A rejected “not habitable, not residential” argument does not automatically rule out a separate mixed-use analysis.
• However, a mixed-use claim still needs a legally sound basis. It is not enough to point to attractive communal facilities and assume they change the SDLT classification.
• The case needs careful review of the title documents, lease, transfer, plans, estate documents, and any rights granted to the buyer.
• Where a building or wider development includes shops, health facilities, or other commercial elements, the analysis may be stronger, but only if the purchased interest actually includes or benefits from them in a way that matters for SDLT.

That is broadly right. In practice, SDLT classification turns on the subject matter of the transaction, not on marketing language or general impressions about the building.

The Law

SDLT is charged under the Finance Act 2003. The residential or non-residential character of a transaction matters because different rate structures apply.

The key starting points are:

• Finance Act 2003, section 43, which deals with the main subject matter of a land transaction.
• Finance Act 2003, section 55, which applies different SDLT rate tables depending on whether the transaction is residential, non-residential, or mixed.
• Finance Act 2003, section 116, which defines “residential property”.

Broadly, “residential property” includes:

• 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 forms part of the garden or grounds of such a building, including land acquired with the dwelling.

If a transaction includes both residential and non-residential property, it is treated as mixed-use and taxed at non-residential rates.

Where a buyer argues that a dwelling was not suitable for use as a dwelling at the effective date of the transaction, the courts have taken a relatively strict approach. 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

The correct analysis is usually done in stages.

First, identify exactly what the buyer acquired. In the case of a flat, that will usually be a leasehold or freehold interest in a dwelling, together with rights over common parts. The legal documents matter more than the sales particulars.

Second, ask whether the property acquired was residential property under section 116. A penthouse flat will normally be a dwelling and therefore residential property unless there is a strong reason to say it was not suitable for use as a dwelling at completion. Since Mudan, that is a harder argument than many buyers assume.

Third, consider whether the transaction also included non-residential property. This is where buyers often overstate the significance of communal amenities.

A shared gym may fall into one of several categories:

• part of the common parts serving the residential building;
• a separate commercial unit owned and operated independently, with residents merely having a licence or membership arrangement;
• a facility forming part of a wider mixed-use development, but not part of the legal interest acquired by the flat buyer.

If the gym is simply part of the common facilities of a residential block, that will usually not convert the flat purchase into a mixed-use transaction. Communal areas that support residential occupation are commonly treated as part of the residential setting.

If, however, the transaction included a separate interest in genuinely non-residential land or premises, the analysis may be different. For example, if the buyer acquired rights over a commercial area that were more than incidental residential rights, or if the title package included a distinct non-residential element, there may be scope to argue that the transaction was mixed-use.

Fourth, distinguish between the building as a whole and the transaction under review. A block may contain shops, treatment rooms, offices, or leisure space. But the relevant question is not whether the building is mixed in everyday language. It is whether the chargeable interest acquired by the buyer included both residential and non-residential property.

Fifth, if the earlier claim was based on the flat being uninhabitable, do not assume the same evidence will support a mixed-use claim. These are different arguments. A failed “unsuitable for use” claim may still leave open a separate point, but the evidence and legal test are not the same.

In most flat cases, a shared residents’ gym on its own is unlikely to be enough. A stronger case would usually require one or more of the following:

• clear title evidence showing the buyer acquired an interest extending beyond a straightforward dwelling and normal residential common parts;
• plans and lease provisions showing rights over a distinct non-residential area;
• evidence that the non-residential element was part of the subject matter of the transaction, not merely nearby or available under a separate arrangement;
• a development structure where commercial elements are legally tied into the acquired interest in a way that affects classification.

Outcome

A flat in a block with a shared gym is not automatically non-residential or mixed-use for SDLT. In most cases, the purchase will still be residential.

A mixed-use argument may be possible, but only where the legal rights acquired show that the transaction included a genuine non-residential element. The presence of a gym, concierge, or other communal feature is not enough by itself.

If the earlier argument was that the dwelling was not habitable, that route is now more difficult where the defects do not meet the relatively high threshold confirmed in Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799.

Practical Steps

If you are assessing a similar SDLT position, the sensible next steps are:

• obtain the transfer, lease, title register, title plan, and any estate documents;
• identify exactly what land and rights were acquired at completion;
• review whether any alleged non-residential element formed part of the chargeable interest, rather than being a separate facility or mere amenity;
• separate any “mixed-use” argument from any “unsuitable for use as a dwelling” argument;
• check whether there is contemporaneous evidence from the completion date, including surveys, photographs, correspondence, and layout plans;
• review any HMRC rejection carefully to see which point was actually refused and why.

Where the transaction concerns a flat in a larger development, the lease and estate structure are usually decisive.

Conclusion

For SDLT, the existence of a shared gym in a residential block does not usually change a flat purchase from residential to mixed-use. The key issue is the legal subject matter of the transaction. If the buyer only acquired a dwelling with ordinary rights over residential common parts, SDLT will normally remain chargeable at residential rates. Any argument based on poor condition or lack of habitability must also now be tested against the stricter approach confirmed in Mudan.

Legal References Used

• Finance Act 2003, section 43
• Finance Act 2003, section 55
• 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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