Guidance on Residential Property and Mixed-Use Land Transaction Considerations

SDLT treatment where a property is part home and part business

For Stamp Duty Land Tax, a property is not treated as mixed-use just because someone works from home. HMRC looks at whether the business area is really a separate commercial part of the building and whether it is still suitable for normal residential use. The outcome depends on the facts, including layout, physical changes, separation from the home, and any planning restrictions.

• A normal home office or study will usually still count as part of the dwelling if it can easily be used as ordinary living space.
• Actual business use alone is not enough; HMRC also considers whether the area remains suitable for use as part of a home.
• Mixed-use treatment is more likely if part of the building is physically separate, used only for business, or adapted with specialist commercial features.
• Planning conditions or other legal restrictions preventing residential use are a strong sign that the area may no longer be part of a dwelling.
• The correct SDLT treatment requires an overall factual assessment of the building, not just the label given to a room or area.

Scroll down for the full analysis.

When a property is partly a home and partly business premises for SDLT purposes

This page explains how HMRC approaches a difficult question in Stamp Duty Land Tax: when a building contains both living space and business space, is it still entirely residential, or is it mixed residential and non-residential property? The answer matters because SDLT treatment can differ depending on whether the property is treated as wholly residential or mixed.

What this rule is about

Some buildings are straightforward. A normal house is residential. A shop is non-residential. The difficulty arises where one building contains both domestic accommodation and space used for work or business.

The legal issue is not answered simply by asking how the rooms are being used on a given day. HMRC’s guidance shows that two different questions may need to be considered:

• whether part of the building is in fact being used as part of a dwelling, and
• whether that part is still suitable for use as a dwelling even if it is currently used for business purposes.

This distinction is important because a room can be used for work and still remain part of a dwelling. Equally, a part of a building may be set aside for commercial use so completely, or altered so significantly, that it is no longer treated as residential in substance.

What the official source says

HMRC draws a distinction between two broad situations.

The first is the ordinary “home office” case. If a room in a house is used as an office, study, or workspace, but it still remains part of the home and is still suitable for normal domestic use, HMRC says the building will normally remain a dwelling. On that view, a home office does not by itself make the property mixed residential and non-residential.

The second is where part of the building is divided off or dedicated to commercial use, such as a house partly used as a doctor’s surgery. In that situation, HMRC says the commercial part must be examined more closely. If part of the building is set aside for commercial use and used separately from the living accommodation, it may be reasonable to say that those rooms are not used as a dwelling.

However, HMRC also says that actual use on its own is not decisive. A room being used for business does not automatically stop it being suitable for use as a dwelling. Key factors include:

• how far the area has been converted for commercial use, and
• how separate it is from the residential part of the building.

HMRC’s view is that if the business rooms could easily be brought back into ordinary domestic use without any adaptation, they may still be suitable for use as part of a dwelling even though they are currently used commercially.

By contrast, if the area has been altered so that it is suitable for business use but not for living accommodation, or if planning restrictions prevent residential use, HMRC says it is more likely that the area is no longer suitable for use as a dwelling.

What this means in practice

You should not assume that any business use creates mixed-use treatment. Many people work from home. A study, spare room, or reception room used as an office will often still be part of the dwelling.

What matters more is whether part of the building has really become a separate commercial area in substance. Questions to ask include:

• Is the area used exclusively for business?
• Is it physically separate from the living accommodation?
• Has it been adapted with specialist commercial features?
• Could it easily be used again as normal living space?
• Are there planning controls that prevent residential use?

If the answer points towards a genuinely separate commercial element, the property may be mixed residential and non-residential. If the answer points towards ordinary domestic rooms that happen to be used for work, the property is more likely to remain wholly residential.

This is a factual exercise. HMRC’s guidance does not lay down a mechanical test. It points to a practical evaluation of the building as it exists and how the relevant area functions within it.

How to analyse it

A sensible way to approach the issue is to work through the following steps.

First, identify the area said to be commercial. Is it just a room used for work, or a distinct part of the building operating as business premises?

Second, look at actual use. Is the area genuinely set aside for business and used separately from the home? Exclusive business use may support mixed treatment, but it is not enough by itself.

Third, look at physical features and layout. Has the area been converted or adapted in a way that makes it function as commercial premises rather than domestic accommodation?

Fourth, ask whether the area is still suitable for use as part of a dwelling. If it could be used as normal residential space without alteration, that points towards residential treatment.

Fifth, check for legal restrictions. If planning conditions or other restrictions prevent residential use, that is a strong factor against the area being suitable for use as a dwelling.

Finally, stand back and consider the building as a whole. The question is not just what label the owner gives the room, but what the property really is in context.

Example

A homeowner uses one bedroom as a study and keeps a desk, computer, and filing cabinet there. The room could still be used as a bedroom without any works. On HMRC’s approach, this would normally remain part of the dwelling, so the property would not usually be treated as mixed simply because of that home office use.

Now take a different case. A house includes two front rooms used only as a dental surgery. They are fitted with specialist equipment and are not used as part of the living accommodation. If those rooms have been adapted so that they are suitable for the surgery but not ordinary domestic use, HMRC’s guidance suggests it is more likely they would not be suitable for use as part of a dwelling. That points more strongly towards mixed residential and non-residential treatment.

Why this can be difficult in practice

The boundary is not always clear. A room may be used only for business, but still be physically no different from an ordinary room in a house. In that case, actual use and physical suitability may point in different directions.

Equally, a building may contain a business area that is not heavily altered, but is clearly run separately from the residential accommodation. HMRC’s guidance suggests that separation and dedicated commercial use matter, but also says that easy reintegration into the home may still mean the area remains suitable for use as a dwelling.

This means there is no single decisive factor. The result depends on the facts and context. Small differences in layout, conversion works, equipment, and planning position may change the analysis.

It is also important to distinguish HMRC’s manual guidance from the legislation itself. The manual explains HMRC’s view of how the rules apply, but the legal answer ultimately depends on the statutory test and the facts of the property being acquired.

Key takeaways

• A normal home office will not usually make a property mixed residential and non-residential.
• Exclusive business use is relevant, but the key questions also include physical adaptation, separation, and continued suitability for residential use.
• If part of the building has become genuine commercial premises, especially with specialist conversion or planning restrictions, mixed-use treatment becomes more likely.

This page was last updated on 24 March 2026

Useful article? You may find it helpful to read the original guidance here: Guidance on Residential Property and Mixed-Use Land Transaction Considerations

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