Can you keep Multiple Dwellings Relief after later building works to the property?

Introduction

A common SDLT question is whether Multiple Dwellings Relief (MDR) can still apply where a buyer purchased a property containing more than one dwelling, but later carried out works that changed the layout or use of part of the building. This issue often arises when HMRC argues that the property was really only one dwelling, or that a later change triggered a clawback of relief.

The key legal questions are usually:

• whether there were two or more dwellings at the effective date of the transaction; and
• whether anything that happened afterwards amounted to a disqualifying event under Schedule 6B to the Finance Act 2003.

In practice, the answer depends heavily on the physical layout, the degree of separation between the units, and what later works actually did.

The Question

A taxpayer bought a residential property and claimed MDR on the basis that, at completion, the building contained more than one dwelling. HMRC later issued a closure notice denying the claim. The taxpayer appealed, arguing that the SDLT return was correct when filed and that later works to the property were safety-driven and structural in nature, not a merger of separate dwellings. Evidence relied on included a chronology, contractor confirmation, and photographs showing the internal arrangement and a lockable fire door.

The practical issue is whether MDR was validly claimed at completion and, if so, whether any later works caused a disqualifying event so that the relief had to be withdrawn.

Nick’s Explanation

Nick’s position was that the appeal should focus on two points: first, the property had to be tested as at the date of completion; second, later works only matter if they fall within the statutory clawback rules.

In anonymised form, his explanation was that:

• the claim was “correctly claimed at the point of completion”;
• the evidence showed the relevant layout and separation within the building at that date;
• there had been “no disqualifying event under paragraph 6 of Schedule 6B of the Finance Act 2003”; and
• the works carried out were supported by contractor evidence as being required for safety and structural reasons.

He also relied on legal analysis including Fiander and Brower [2021] UKUT 156 (TCC), which is an important authority on what counts as a separate dwelling for MDR purposes.

The Law

MDR was contained in Schedule 6B to the Finance Act 2003. Although MDR has now been abolished for most new transactions, it still matters for historic transactions, amendments, enquiries and appeals relating to periods when the relief was available.

For MDR to apply, the chargeable transaction had to involve an interest in at least two dwellings. The core question is whether, on the effective date of the transaction, the property included more than one “dwelling” for SDLT purposes.

The legislation does not reduce the test to a single factor. The case law shows that the tribunal and courts look at the overall character of the unit and whether it is suitable for use as a single dwelling. Relevant features often include:

• separate access or a meaningful degree of separation;
• sleeping, washing and living facilities;
• kitchen or food preparation arrangements;
• whether the unit can function independently in ordinary residential use; and
• the physical configuration at the effective date.

Paragraph 6 of Schedule 6B deals with disqualifying events. Broadly, if MDR was claimed and, within the relevant period, the number of dwellings is reduced or the factual basis of the claim is undermined by a later event falling within the legislation, relief can be withdrawn.

That means there are two separate stages:

1. Was MDR valid on completion?
2. If yes, did a later disqualifying event occur?

Those questions should not be blurred together.

Where arguments arise about a unit being uninhabitable or 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. A property will not fall outside the dwelling concept merely because it needs repair, modernisation or substantial works. The condition must be serious enough to take it outside suitability for use as a dwelling in the legal sense.

Analysis

The correct approach is to work through the issue in stages.

First, identify the relevant date. For MDR, the starting point is the effective date of the transaction, usually completion. The layout, facilities and degree of separation at that date are critical.

Second, examine whether there were at least two dwellings at that time. Evidence such as plans, photographs, fire doors, separate access arrangements, lockable divisions, kitchens, bathrooms and living accommodation may all be relevant. The question is not whether the property could be improved, altered or later occupied differently. It is whether each unit was, at completion, suitable for use as a single dwelling.

Third, apply Fiander and Brower [2021] UKUT 156 (TCC). That case confirms that the test is practical and objective. A unit does not have to be legally separate or held under a separate title to count as a dwelling. But it must have enough of the characteristics of independent residential living. Internal connection between parts of a building does not automatically prevent there being more than one dwelling, though it may be relevant depending on the facts.

Fourth, consider any works after completion. HMRC may argue that if the buyer later removed separation, opened up internal space, or converted the building into a single residence, that shows there was only one dwelling all along. That is not necessarily correct. Later works may simply show that the buyer changed the property after purchase. The legal question is whether those works created a disqualifying event under paragraph 6, not whether they retrospectively rewrite the position at completion.

Fifth, analyse the nature of the works. If the evidence shows that the works were carried out for safety, compliance or structural necessity, that may support the argument that they should not be characterised as a voluntary merger of dwellings in the sense HMRC alleges. The detail matters. For example:

• Were walls removed or openings created so that two units became one?
• Were kitchens or bathrooms taken out permanently?
• Was the separate occupation capability lost?
• Or were the works limited, temporary, or required for safety and repair?

Sixth, if HMRC raises habitability or suitability arguments, those must be tested carefully. Following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, the bar for saying a unit was not suitable for use as a dwelling is relatively high. Serious disrepair alone will not always be enough. So if HMRC suggests that one unit was too poor, too unsafe or too incomplete to count as a dwelling, the factual evidence needs to be measured against that higher threshold.

Finally, the taxpayer’s evidence is central. A well-prepared appeal will usually include:

• a chronology from purchase onwards;
• photographs from around completion;
• contractor or surveyor evidence explaining the works;
• floor plans and measurements where available; and
• a legal analysis tied to the statute and authorities.

That is especially important where HMRC has already issued a closure notice.

Outcome

The practical conclusion is that later works do not automatically defeat MDR. If the property comprised two or more dwellings at completion, the claim may have been valid from the outset. HMRC would then need to show either:

• that there were not in fact multiple dwellings at the effective date; or
• that a later event fell within paragraph 6 of Schedule 6B so that the relief was clawed back.

Where the evidence supports separate dwelling status at completion and the later works were safety-driven or structural rather than a true statutory disqualifying event, there may be good grounds to challenge HMRC’s denial of MDR.

Practical Steps

If you are assessing a similar MDR dispute, the next steps are usually:

1. Establish the effective date of the transaction and gather evidence from that time.
2. Collect photographs, plans, sale particulars, mortgage valuation material and any survey reports.
3. Identify the features said to make the second unit a separate dwelling.
4. Prepare a clear timeline of all post-completion works.
5. Obtain contractor, architect or surveyor evidence explaining why works were carried out and what they changed.
6. Check whether HMRC is arguing “not a dwelling at completion” or “later disqualifying event”, because those are different arguments.
7. Review the facts against Fiander and Brower [2021] UKUT 156 (TCC) and, where condition is in issue, against Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799.
8. If a closure notice has been issued, make sure any review or appeal deadlines are protected.

Conclusion

MDR cases turn on facts, timing and evidence. The property must be tested as it stood at completion, and later works only matter if they amount to a statutory disqualifying event. In a case where the building genuinely contained more than one dwelling at completion and the later works were safety-related or structural, HMRC’s refusal of MDR may be open to challenge.

Legal References Used

• Finance Act 2003, Schedule 6B
• Finance Act 2003, Schedule 6B, paragraph 6
• Fiander and Brower [2021] UKUT 156 (TCC)
• Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799

This page was last updated on 22 March 2026.

See all questions and answers categorized in this sitemap. Or use Google site search below.