Can you save SDLT when buying a house to convert into an HMO?

Introduction

People often ask whether they can reduce Stamp Duty Land Tax (SDLT) when buying a house that they plan to convert into a house in multiple occupation (HMO). The answer usually depends on what is being bought at the date of completion, not what the buyer intends to do with it later.

In some cases, buyers look at whether the property is so badly damaged or derelict that it is not suitable for use as a dwelling on the purchase date. If that threshold is met, non-residential SDLT rates may apply. But the legal test is now relatively strict, and poor condition or the need for renovation will not usually be enough.

The Question

A buyer is considering purchasing a detached probate property for around £665,000 and intends to convert it into an HMO after completion. The buyer wants to know whether there are any legitimate SDLT savings available.

Nick’s Explanation

Nick’s main point was that the intended conversion into an HMO does not itself create an SDLT saving on the purchase. The key question is the condition of the property at the effective date of the transaction.

In anonymised form, his explanation was:

“The most realistic area to consider is the property’s condition. If the dwelling is genuinely derelict and not suitable for use as a residence at completion, it may be possible to assess the purchase as non-residential and apply non-residential SDLT rates. If the property is simply dated, unmodernised, or in need of renovation, that is much less likely to work.”

He also noted that Multiple Dwellings Relief would not assist where the buyer is acquiring a single house and later converting it into an HMO. That is because the purchase is of one dwelling at the time of acquisition, and in any event Multiple Dwellings Relief was abolished for most transactions with effect from 1 June 2024.

The Law

SDLT is charged under the Finance Act 2003. For residential property, the usual residential rates apply where the subject matter of the transaction consists of a dwelling. The classification depends on the property’s status at the effective date of the transaction.

The question whether a building is “suitable for use as a dwelling” has been considered in a number of cases. A property can fail to count as residential if, at completion, it is in such a state that it is not suitable for use as a dwelling. However, this is a high threshold.

That threshold is now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799. The Court of Appeal confirmed that the test is not satisfied merely because a property is old, run down, in poor repair, or requires significant works. The condition must be serious enough that the building is not suitable for use as a dwelling at the relevant time.

Where a property is residential at completion, later works or a later change of use do not normally alter the SDLT treatment of the purchase.

As to Multiple Dwellings Relief, that relief was withdrawn for most transactions from 1 June 2024. Even before abolition, buying one house with the intention of later converting it into an HMO would not usually mean that multiple dwellings were being acquired on completion.

Analysis

The SDLT position can be analysed in four steps.

1. What is being bought on the completion date?

   If the buyer is purchasing a single detached house, the starting point is that this is a residential property transaction.

2. Does the future HMO conversion change that?

   No. SDLT is generally determined by the nature and condition of the property at the effective date of the transaction. A plan to convert the house into an HMO later does not convert the purchase into a non-residential acquisition.

3. Could the property be treated as non-residential because it is not suitable for use as a dwelling?

   Possibly, but only if the facts are strong. If the property is truly derelict, with defects so serious that it cannot sensibly be lived in at completion, there may be an argument for non-residential treatment. But if it is merely unmodernised, shabby, vacant, or in need of repair, that is unlikely to be enough. Following Mudan, the courts have set the bar relatively high.

4. Could Multiple Dwellings Relief help?

   No. Buying one house and later reconfiguring it as an HMO is not the same as acquiring multiple dwellings at completion. Also, the relief was abolished for most transactions from 1 June 2024.

So, in most ordinary probate-house purchases, the buyer should expect the normal residential SDLT rules to apply unless the building’s condition is exceptionally poor in legal terms.

Outcome

If a buyer purchases a single house for about £665,000 with the intention of converting it into an HMO, there is usually no special SDLT saving just because of that future plan.

The only realistic area to examine is whether the property was genuinely not suitable for use as a dwelling at completion. That argument is now harder to establish than many buyers assume, especially after Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799.

If the property is simply dated or needs renovation, the safer view is usually that residential SDLT applies.

Practical Steps

1. Review the property’s actual condition at the purchase date.

   Gather sales particulars, photographs, survey reports, and any contractor evidence showing the state of the building on completion.

2. Distinguish between “poor condition” and “not suitable for use as a dwelling”.

   A lack of modern kitchen fittings, old bathrooms, decorative disrepair, or general refurbishment needs will not usually be enough.

3. Check whether there are severe defects.

   Examples might include major structural failure, no functioning basic facilities combined with wider serious defects, or conditions making occupation unrealistic at completion. The evidence must be strong.

4. Do not rely on the planned HMO use as the SDLT saving point.

   That future use does not usually affect the SDLT classification of the purchase itself.

5. Take advice before filing if considering non-residential treatment.

   This is a fact-sensitive area and HMRC may challenge weak claims.

Conclusion

Buying a house and later converting it into an HMO does not usually produce an SDLT saving. The main issue is whether the property was so defective at completion that it was not suitable for use as a dwelling. That test is now relatively demanding, and after Mudan many properties in poor or dated condition will still be treated as residential for SDLT purposes.

Legal References Used

• Finance Act 2003
• Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799
• Rules abolishing Multiple Dwellings Relief for most transactions with effect from 1 June 2024

This page was last updated on 22 March 2026.

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