Do you pay SDLT twice when buying a house with an annex used as a holiday let?

Introduction

People often ask this question when buying a home that includes a self-contained annex, especially where the annex is being used as a holiday rental. The concern is usually whether Stamp Duty Land Tax (SDLT) is charged separately on the main house and the annex, or whether keeping the annex as a holiday let changes the tax position.

The short answer is that SDLT is not paid twice on a single purchase. The real issue is how the property is classified for SDLT purposes. That classification can affect which SDLT rate applies to the whole transaction.

The Question

A buyer is considering purchasing a property for £750,000. The property includes an annex connected to the main house by an internal door. The annex is currently used as a holiday rental, and the buyer wants to continue that use after completion. The question is whether that means SDLT would be payable twice, or whether a different SDLT treatment applies.

Nick’s Explanation

Nick’s core point is that SDLT is charged on the land transaction itself, not separately on each part of the building in the sense of paying the tax twice. On a single purchase, there is one SDLT calculation, but the applicable rates depend on whether the property is treated as residential or mixed-use.

In anonymised form, his explanation was that:

“You would not pay SDLT twice on a single purchase. The important question is whether the property is wholly residential, or whether it is mixed-use because part of it is genuinely non-residential. If it is mixed-use, the non-residential SDLT rates may apply to the whole price. If it is wholly residential, the residential rates apply.”

He also noted that Multiple Dwellings Relief is no longer available for transactions with an effective date on or after 1 June 2024, so that relief cannot now be relied on in a case of this kind.

The Law

SDLT is charged under Part 4 of the Finance Act 2003 on land transactions in England and Northern Ireland.

The main charging and rate provisions relevant here are:

• Finance Act 2003, section 55, which sets the SDLT rates
• Finance Act 2003, section 116, which defines residential property and non-residential property

Broadly:

• Residential rates in Table A apply if the subject matter of the transaction is residential property.
• Non-residential or mixed-use rates in Table B apply if the transaction is wholly non-residential or mixed-use.

A transaction is mixed-use if it includes both residential and non-residential property.

Section 116 provides the framework. Property used as a dwelling is residential property. Land or buildings that do not fall within the residential definition may be non-residential. In some cases, a genuinely commercial element can mean the transaction is mixed-use.

It is also important that Multiple Dwellings Relief, which previously sometimes applied where more than one dwelling was acquired, was abolished for transactions with an effective date on or after 1 June 2024.

Analysis

The question can be broken down into four steps.

First, there is only one SDLT transaction.

If a buyer purchases one property title or one overall property transaction for £750,000, SDLT is not charged twice simply because there is both a main house and an annex. There is one return and one SDLT calculation for the transaction, subject to the normal rules.

Second, the annex does not automatically create a separate SDLT charge.

The existence of an annex, even one capable of separate occupation, does not mean SDLT is separately due on the annex and again on the main house. The tax treatment depends on the character of the whole transaction.

Third, the key issue is whether the annex creates a mixed-use purchase.

If the annex is truly being used as part of a commercial operation, such as a holiday letting business, a buyer may ask whether that makes part of the property non-residential. If so, the whole acquisition may potentially be treated as mixed-use, which would bring in the non-residential SDLT rates.

However, this is highly fact-sensitive. It is not enough simply to say that the annex has been used for holiday guests. HMRC and the courts look at the actual nature of the property and the subject matter being acquired. If the annex is physically connected to the main house by an internal door and forms part of the same residential setting, there may be a strong argument that the property remains wholly residential despite short-term letting use.

The fact that the annex is ancillary to the main house may point away from mixed-use treatment, depending on the exact facts. The legal and practical degree of separation matters, as does whether the annex is genuinely part of a business element of the property at the time of purchase.

Fourth, the buyer’s intended future use is not always decisive.

SDLT is assessed by reference to the transaction being entered into and the property acquired at the effective date of the transaction. A buyer’s intention to continue holiday letting may be relevant to understanding the nature of the acquisition, but it does not automatically determine the SDLT classification on its own.

So, if the property is acquired as a house with an ancillary annex that remains part of the same residential property, residential rates may still apply to the full £750,000. If, on the other hand, the facts support the view that the annex is a genuine non-residential element, mixed-use rates may apply to the whole purchase price.

In cases where buyers consider whether an annex or outbuilding is not suitable for use as a dwelling, the threshold is now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799. That decision makes clear that arguments based on disrepair or limited usability will not easily take property outside the residential regime. A property generally needs to fail the suitability test in a more serious way before it is treated as not suitable for use as a dwelling.

Outcome

The practical answer is that a buyer would not pay SDLT twice on this purchase.

The real question is whether the acquisition is:

• wholly residential, in which case residential SDLT rates apply to the full £750,000, or
• mixed-use, in which case non-residential SDLT rates may apply to the full £750,000.

On the limited facts given, the presence of a connected annex currently used as a holiday rental does not by itself prove mixed-use treatment. Much depends on the physical layout, legal rights, actual use at completion, and whether the annex is truly separate from the residential use of the main house.

Practical Steps

• Review the title documents to see whether the annex forms part of the same legal title and residential curtilage.
• Check the physical layout carefully, including whether the annex is internally connected and how separate it really is in practice.
• Gather evidence of the annex’s current use, including booking records, planning position, council tax or business rates treatment, and any commercial letting arrangements.
• Consider whether the annex is genuinely a non-residential element at the effective date of the transaction, rather than simply accommodation within a larger dwelling.
• Do not assume that past holiday-let use automatically means mixed-use SDLT treatment.
• Do not rely on Multiple Dwellings Relief for transactions on or after 1 June 2024, because that relief has been abolished.
• If the SDLT position is important to the affordability of the purchase, obtain transaction-specific advice before exchange.

Conclusion

Buying a house with an annex used as a holiday let does not mean SDLT is paid twice. There is one SDLT charge on the transaction. The important issue is whether the property is wholly residential or mixed-use. In many annex cases, that answer turns on detailed facts rather than labels such as “holiday rental”.

Legal References Used

• Finance Act 2003, Part 4
• 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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