How stamp duty counts separate homes in one building
Physical layout matters
For SDLT, an annexe or part of a building may need separate consideration. HMRC focuses on the real layout at the relevant time.
- Check facilities in each area
- Check independent access and privacy
- Keep dated plans and photographs
Scroll down for the full analysis.
Read the original guidance here:
How stamp duty counts separate homes in one building
A house with an annexe, converted floor or unfinished extension may look like one property. For stamp duty, buyers and HMRC assess the physical layout to decide whether the purchase includes one home or more, even where the building appears to be a single property. Layout can change the SDLT treatment.
What this rule is about
A property’s label does not decide. SDLT looks at what was physically there when it treated the purchase as happening.
A building can include part of a building. An annexe or self-contained area may therefore require separate consideration, rather than automatic treatment as part of the main house.
What the official source says
HMRC’s manual says physical configuration is very important when deciding how many separate homes there are.
For the higher-rates rules, legislation says a building or part of one can count as a dwelling if it is used or suitable for use as a single home, or is being built or adapted for that use. The definition matters.
- HMRC looks at the facilities available in the area.
- It looks at whether the area has independent access.
- It also looks at whether the occupier has privacy from other parts of the property.
- HMRC says missing one of these features will normally raise serious doubt.
- If building or conversion work is underway, HMRC says the finished layout determines the number of separate homes.
What this means in practice
One locked internal door does not settle the issue. Nor does calling part of the property an annexe. Ask whether it functions independently. Consider the whole layout.
People often miss the distinction between future plans and current facts. When work is underway, keep clear records of completed work and the finished design so you can show both the current position and what the project will become. Current facts matter.
- Check each area, not just the building as a whole.
- Record entrances, locks, corridors and any shared routes.
- List the facilities each area had at the relevant time.
- Keep the sale details, plans and dated photographs.
- Do not assume a council description decides the SDLT answer.
How to analyse it
Start with the date SDLT took effect. Usually this is completion, although an earlier event can sometimes make the contract effective for SDLT. Then compare the evidence with the property’s real layout on that date.
- Identify every part said to be a separate home.
- Check whether it had the facilities needed for everyday living.
- Ask how someone could enter it without going through private living space.
- Check what privacy it had from the rest of the building.
- Where work continued, obtain the approved plans and evidence of progress.
- Apply the statutory definition that governs the SDLT issue in question.
Example
As an illustration, Priya buys a house with a ground-floor annexe. The annexe had separate facilities.
It had its own outside door, its own kitchen and bathroom, and no shared living space. Those facts point towards a separate home.
If the kitchen was still being installed and the conversion was unfinished, HMRC’s manual says the finished layout would instead be important. The answer still depends on the full evidence.
Why this can be difficult in practice
Properties rarely fit neat labels. An annexe may have a private entrance but share key facilities.
Another area may have all the facilities but require entry through the main home’s living room.
HMRC’s manual is useful evidence of its approach. It is not the law itself. The statute and the facts of the individual property remain decisive.
- A separate postal address is not the whole answer.
- Planning permission alone does not prove the finished physical layout.
- Marketing language may not match what existed at the relevant time.
- Shared access can matter, but its effect depends on the wider arrangement.
Key takeaways
- Physical layout can change how SDLT counts parts of one property.
- Facilities, access and privacy are central to HMRC’s view.
- Use dated evidence of the property and any building work.
Technical analysis
For advisers, and for anyone who wants to check the law behind this page. You do not need this section to understand the guidance above.
Legislation
- FA 2003 section 44 — when a contract purchase has its effective date
- FA 2003 section 116 — what counts as residential property
- FA 2003 Schedule 4ZA para 18 — what counts as a home for higher rates
Official guidance
The pages below are HMRC’s guidance. Guidance is not law. It sets out how HMRC reads the legislation, and it is not binding on you, on a tribunal or on a court. Where guidance and the legislation differ, the legislation wins. HMRC can also change or withdraw guidance, and it may not cover your facts.
Where this is not settled
- There is no fixed checklist that guarantees an annexe, floor or converted area is a separate home.
- The weight given to access, facilities and privacy depends on the property’s full physical layout and condition at the relevant time.
- Plans for future work do not necessarily show the layout that existed when SDLT took effect.
Evidence you would need
This kind of case is decided on the facts of the individual property. These are the records that usually settle it, and the ones an adviser would ask you for.
- Dated floor plans — the rooms, internal links, entrances and layout at the relevant time
- Photographs or video taken near completion — the actual physical state, doors, facilities and separation between areas
- A room-by-room inventory — which cooking, washing, sleeping and living facilities each area had
- Sale particulars and estate-agent photographs — how the property was described and configured when marketed
- The contract, completion statement and possession records — when SDLT took effect and which layout must be considered
- Planning applications, approved plans and building-control records — what construction or adaptation was authorised and how far it had progressed
- Building contracts, invoices and dated progress photographs — whether works were ongoing and the likely finished configuration
- Land Registry title, filed plan and rights-of-way documents — the land bought and any separate or shared access rights
- A surveyor’s report prepared near the relevant date — the condition, layout and practical separation of the areas
Explore this with an AI
Readers often want to test their own situation. Copy the prompt below into ChatGPT, Claude or Gemini. It hands the model the actual legislation for this page rather than letting it answer from memory, and tells it to be explicit about what is uncertain. What comes back is information, not advice – check it against the links above.
I am researching UK Stamp Duty Land Tax (SDLT), which applies in England and Northern Ireland. MY QUESTION How stamp duty counts separate homes in one building [Replace this with your own situation: what you are buying, the price, the dates, who the buyer is, and what you plan to do with the property.] THE LAW THIS TURNS ON - FA 2003 section 44 - when a contract purchase has its effective date https://www.legislation.gov.uk/ukpga/2003/14/section/44/2025-11-17 - FA 2003 section 116 - what counts as residential property https://www.legislation.gov.uk/ukpga/2003/14/section/116/2025-11-17 - FA 2003 Schedule 4ZA para 18 - what counts as a home for higher rates https://www.legislation.gov.uk/ukpga/2003/14/schedule/4ZA/paragraph/18/2025-11-17 Guidance page from HMRC on this topic (guidance, not law): https://www.gov.uk/hmrc-internal-manuals/stamp-duty-land-tax-manual/sdltm00420 HOW I WANT YOU TO ANSWER 1. Work from the legislation above. Read it before answering. Guidance from HMRC is its view of the law, not the law, and does not bind a tribunal or a court. 2. Tell me what the rule actually requires, in plain English. 3. Tell me which facts decide the answer, and which facts would change it. 4. Tell me what evidence I would need to support the position. 5. Be explicit about anything unsettled or fact-sensitive. Do not guess. 6. Your training data has a cutoff and SDLT rates and reliefs change at fiscal events. Say so if you are not sure the law is current. POINTS ALREADY KNOWN TO BE UNCERTAIN ON THIS TOPIC - There is no fixed checklist that guarantees an annexe, floor or converted area is a separate home. - The weight given to access, facilities and privacy depends on the property's full physical layout and condition at the relevant time. - Plans for future work do not necessarily show the layout that existed when SDLT took effect. Do not give me a conclusion you cannot support from the provisions above.
Legislation links show Finance Act 2003 as it stood on 2025-11-17. The law may have changed since, and the rules that apply are those in force on the date of your transaction. The official guidance this page is based on is here.
This page was last updated on 31 August 2026
Useful article? You may find it helpful to read the original guidance here: How stamp duty counts separate homes in one building
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