Stamp duty relief for a block of flats: what happens after changes?
In short
HMRC’s historic example shows that later changes to a block of flats can alter the stamp duty result.
- Leasing two flats did not trigger a new calculation in the example.
- Merging six flats into three did.
- The original £1,000,000 was then divided by five, not eight.
Scroll down for the full analysis.
Read the original guidance here:
Stamp duty relief for a block of flats: what happens after changes?
Stamp duty relief for a block of flats: what happens after changes?
Buying several flats at once could reduce stamp duty when the price is spread across the homes, but later work during the relevant period may alter that result. It can. HMRC’s example shows that merging flats may mean more SDLT is due, even though granting leases of two flats did not.
What this rule is about
This is an historic example about the relief for buying more than one home at once. The relief calculated tax by finding the average price per home, then multiplying the result by the number of homes.
That can make a large difference. Yet, if something changes during the set period after purchase and would have affected the original calculation, the calculation may no longer remain fixed for the relief. A recalculation may follow.
What the official source says
HMRC gives an example of a buyer who pays £1,000,000 for the freehold of a block containing eight flats. Initially, the price is divided by eight. The average for each flat is £125,000.
- HMRC treats the purchase as one involving more than one home.
- Its initial calculation uses £1,000,000 divided by eight: £125,000.
- Six months later, the buyer grants 99-year leases of two flats to unrelated people.
- HMRC says those leases do not require a new tax calculation.
- Another six months later, the other six flats are combined into three flats.
- HMRC says that change does require a new calculation.
The legislation permits a recalculation if an event during the relevant period would have produced more tax had it happened just before the original purchase. The event is treated as if it had happened then.
HMRC says the later leases do not bring that period to an end. In its view, the buyer has not sold the whole interest bought in the block.
What this means in practice
For the example, HMRC counts five homes after the work: the three new larger flats and the two flats with long leases. It then divides the same £1,000,000 by five, producing £200,000 per home.
That higher average may result in a higher SDLT bill. It is not based on the cost of the building work. Instead, it follows from the reduced number of homes used in the calculation.
- Keep the original plans and the plans after any work.
- Record when each lease was granted.
- Check whether works merge homes or split them.
- Revisit the SDLT calculation before changing the layout.
The source says the buyer must send a further SDLT return and pay any extra tax within 30 days of the event. That deadline forms part of this historic relief rule.
How to analyse it
Begin with the original purchase, then trace what happened to every flat through each later lease, sale, and building change during the relevant period. Both counts matter.
- Confirm the date of the original purchase.
- Check that the historic relief was claimed.
- Identify how many separate homes existed at purchase.
- List every later lease, sale and building change.
- Ask whether the change happened during the relevant period.
- Work out whether the change would have meant more tax if it existed before purchase.
- If so, recalculate using the original price and the revised number of homes.
Example
Here is HMRC’s illustration. Amir buys eight flats for £1,000,000. The initial average is £125,000: £1,000,000 divided by eight. He later grants long leases of two flats, then converts the remaining six flats into three.
HMRC’s revised average is £200,000: £1,000,000 divided by five. The five consist of the three combined flats and the two flats that have been leased. HMRC says Amir must recalculate the SDLT using that revised figure.
Why this can be difficult in practice
You might assume that only a sale can affect the relief, yet HMRC’s example shows that, where flats are physically changed during the relevant period, those changes can matter too. It is not that simple.
The example is not, however, a ready-made tax calculation for every block. It does not provide the purchase date or all the facts behind the higher-rate treatment.
- A lease covering only part of a block may not have the same effect as a sale of the whole interest.
- Combining flats can reduce the number of homes in the calculation.
- The dates of leases and works can decide whether the adjustment rules apply.
- Historic SDLT rates must be checked for the original purchase date.
Key takeaways
- In this example, HMRC says long leases of two flats did not trigger a recalculation.
- HMRC says merging six flats into three did trigger one.
- Any extra SDLT was due through a further return within 30 days.
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 58D — claims for relief on buying multiple homes
- FA 2003 Schedule 6B para 2 — transactions that can qualify for the relief
- FA 2003 Schedule 6B para 3 — meaning of a multiple home transaction
- FA 2003 Schedule 6B para 5 — how tax is worked out under relief
- FA 2003 Schedule 6B para 6 — tax adjustment after later events
- FA 2003 Schedule 6B para 7 — what counts as a home for relief
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
- The source does not give the date of the original purchase. That date is needed to confirm which version of the relief and rates applied.
- Whether a later change produces more tax must be tested against the statutory rules and the facts at the time.
- The source does not explain why the higher SDLT rates applied to its buyer.
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.
- The completion or effective date of the original purchase
- The SDLT return and relief claim for the original purchase
- Plans showing the number and layout of homes before and after the works
- Lease documents for any flats let after the purchase
- Dates and records of the building works
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 Stamp duty relief for a block of flats: what happens after changes? [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 58D - claims for relief on buying multiple homes https://www.legislation.gov.uk/ukpga/2003/14/section/58D/2025-11-17 - FA 2003 Schedule 6B para 2 - transactions that can qualify for the relief https://www.legislation.gov.uk/ukpga/2003/14/schedule/6B/paragraph/2/2025-11-17 - FA 2003 Schedule 6B para 3 - meaning of a multiple home transaction https://www.legislation.gov.uk/ukpga/2003/14/schedule/6B/paragraph/3/2025-11-17 - FA 2003 Schedule 6B para 5 - how tax is worked out under relief https://www.legislation.gov.uk/ukpga/2003/14/schedule/6B/paragraph/5/2025-11-17 - FA 2003 Schedule 6B para 6 - tax adjustment after later events https://www.legislation.gov.uk/ukpga/2003/14/schedule/6B/paragraph/6/2025-11-17 - FA 2003 Schedule 6B para 7 - what counts as a home for relief https://www.legislation.gov.uk/ukpga/2003/14/schedule/6B/paragraph/7/2025-11-17 HMRC's guidance page on this topic (guidance, not law): https://www.gov.uk/hmrc-internal-manuals/stamp-duty-land-tax-manual/sdltm29983 HOW I WANT YOU TO ANSWER 1. Work from the legislation above. Read it before answering. HMRC guidance is HMRC's 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 - The source does not give the date of the original purchase. That date is needed to confirm which version of the relief and rates applied. - Whether a later change produces more tax must be tested against the statutory rules and the facts at the time. - The source does not explain why the higher SDLT rates applied to its buyer. 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 1 September 2026
Useful article? You may find it helpful to read the original guidance here: Stamp duty relief for a block of flats: what happens after changes?
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