Can you reclaim the higher SDLT rates if you buy a house split into two flats and later sell your old home?

Introduction

This is a common Stamp Duty Land Tax question where a buyer wants to move home, but the new property is unusual. The difficulty usually arises where a building looks like one house from the outside but is legally or physically arranged as two self-contained flats at the date of purchase.

Many buyers assume that if the property is bought on one title, or if they intend to turn it back into a single house after completion, they will automatically be able to reclaim the higher rates of SDLT once they sell their previous main residence. The position is not always that simple. For SDLT, the key issue is usually how many dwellings are being acquired at the effective date of the transaction, not just how the property is described in the contract or how the buyer intends to use it later.

The Question

A buyer plans to purchase a semi-detached building as a second home. At the time of purchase, the building is divided into two self-contained flats and there is planning-related evidence confirming its lawful use in that form. The buyer intends to buy the whole building, carry out works to turn it back into a single home, move in, and then sell their existing main residence within three years. The question is whether the buyer can reclaim the higher rates of SDLT paid on purchase, or whether HMRC may say that the buyer acquired two dwellings rather than one replacement main residence.

Nick’s Explanation

Nick’s initial view focused on title structure, but after further research he refined the position. His final explanation was that the decisive issue is not simply whether the property is held under one title number. The more important SDLT question is whether, at the date of purchase, the building consists of one dwelling or two.

In anonymised form, Nick’s key reasoning was:

“The relevant law is Schedule 4ZA of the Finance Act 2003. A refund of the higher rates is available where the buyer intended the purchased dwelling to be the buyer’s only or main residence and then disposes of the former main residence within three years. But the legislation refers to the purchased dwelling in the singular. If the property acquired is, in substance, two self-contained flats, HMRC is likely to treat that as two dwellings even if they are bought together and even if the buyer plans to convert them into one home later.”

He also explained that a single title does not necessarily solve the problem. If the building is functionally arranged as two separate self-contained homes at completion, SDLT may still treat the acquisition as one of multiple dwellings. In that case, the replacement of main residence refund may not be available.

The Law

The higher rates for additional dwellings are contained in Schedule 4ZA to the Finance Act 2003.

For a refund after a later sale of the previous main residence, the central provision is paragraph 3(7) of Schedule 4ZA. In broad terms, a refund may be claimed where:

• on the effective date of the purchase, the buyer intended the purchased dwelling to be the buyer’s only or main residence;
• the buyer disposes of a major interest in the former dwelling within three years after the purchase; and
• the former dwelling had been the buyer’s only or main residence during the three years before the new purchase.

Paragraph 18(2) of Schedule 4ZA explains when a building or part of a building counts as a dwelling. In summary, a building or part counts as a dwelling if it is used or suitable for use as a single dwelling, or is being constructed or adapted for such use.

That matters because SDLT looks at the number of dwellings actually being acquired. A building can be on one legal title and still contain more than one dwelling for SDLT purposes.

If a transaction involves more than one dwelling, paragraph 5 of Schedule 4ZA may become relevant. That paragraph deals with cases involving multiple dwellings. The refund rules for replacement of a main residence are much narrower and are framed around the purchase of a single dwelling intended as the new main residence.

Where buyers argue that a property was not suitable for use as a dwelling at the date of purchase, the threshold is now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799. A property will not fall outside the dwelling rules merely because it needs renovation, modernisation or substantial works. The condition must be serious enough to mean it is not suitable for use as a dwelling at the effective date.

Analysis

The analysis should be done in stages.

First, ask whether the buyer is replacing a main residence in the ordinary sense. If the buyer still owns their old main residence at the time of buying the new property, the higher rates will usually be payable up front. A refund may then be possible if the old main residence is sold within three years and the statutory conditions are met.

Second, identify what is being bought at completion. This is the crucial step. If the building is arranged as two self-contained flats, SDLT may treat the buyer as acquiring two dwellings, even if:

• the whole building is bought in one contract;
• there is only one Land Registry title;
• the buyer intends to occupy the whole building personally; or
• the buyer plans immediate works to restore it into a single house.

Third, consider the physical and functional facts at the effective date. Relevant indicators may include separate entrances, separate kitchens, separate bathrooms, separate utility arrangements, internal separation, independent occupation, and planning or lawful use evidence showing two flats. If those facts point to two self-contained units, HMRC is likely to say the transaction involves two dwellings.

Fourth, ask whether later conversion changes the SDLT result. Usually it does not. SDLT is assessed at the effective date of the transaction. What the buyer does afterwards may be relevant evidence in some contexts, but it does not generally alter the character of what was bought on completion.

Fifth, consider whether a single title is enough to make it one dwelling. On the reasoning set out above, no. Title is relevant to the legal mechanics of the purchase, but it is not conclusive on the number of dwellings for SDLT.

That means the buyer’s position is weaker than it first appears. If the property is genuinely two self-contained flats at completion, the buyer may struggle to satisfy the replacement of main residence refund conditions because those provisions are directed at the purchase of a single dwelling intended as the new main residence.

There is one possible area for closer factual review: whether the building is truly two dwellings at the date of purchase. If, despite the history or paperwork, it is no longer functionally arranged as two self-contained units, there may be room to argue that only one dwelling is being acquired. But where there is clear evidence of lawful use as two flats and the layout supports that conclusion, HMRC is likely to treat it as two dwellings.

It is also worth avoiding a separate misunderstanding. Some buyers wonder whether they can argue that one or both flats are uninhabitable, so that the building should not count as multiple dwellings. That argument is now difficult unless the condition is genuinely severe. Following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, the threshold for showing a property is not suitable for use as a dwelling is relatively high.

Outcome

The practical conclusion is that buying a building which is divided into two self-contained flats may prevent a later refund of the higher SDLT rates, even if the whole building is bought under one title and even if the buyer later converts it into a single house.

The likely HMRC view is that SDLT looks at the number of dwellings acquired at the date of purchase. If that is two, the replacement of main residence refund under Schedule 4ZA paragraph 3(7) may not be available.

So the answer is not “single title means safe”. The safer conclusion is that the dwelling analysis comes first, and title alone does not settle the issue.

Practical Steps

A buyer in this position should work through the following points before exchange:

• Obtain the title documents, lease documents if any, and the contract package to confirm exactly what is being acquired.
• Review the physical layout at the date of purchase, including entrances, kitchens, bathrooms, meters, services and internal access.
• Check planning records, lawful development certificates and any building control history that may support treatment as two flats.
• Ask the conveyancer to advise specifically on the number of dwellings being acquired for SDLT purposes, not just the number of titles.
• Consider whether the old main residence can be sold before the new purchase if the refund position is too uncertain.
• Do not assume that intended renovation or de-conversion after completion will secure a refund.
• Be cautious about any argument that the property was not suitable for use as a dwelling unless the condition evidence is very strong, particularly after Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799.

Conclusion

If a buyer purchases a building that is genuinely arranged as two self-contained flats at completion, the later sale of their old home may not entitle them to a refund of the higher SDLT rates. The key question is how many dwellings are acquired at the effective date, not how many titles there are and not what works the buyer plans to carry out afterwards.

Legal References Used

• Finance Act 2003, Schedule 4ZA
• Finance Act 2003, Schedule 4ZA, paragraph 3(7)
• Finance Act 2003, Schedule 4ZA, paragraph 5
• Finance Act 2003, Schedule 4ZA, paragraph 18(2)
• 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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