Stamp duty where you buy land with a building contract
When building costs count for SDLT
A land purchase with a linked construction contract needs careful analysis. The result depends on when work happens and whether the land and building agreements truly stand alone.
- Later work may fall outside SDLT if all statutory conditions apply.
- Completed work can form part of what you bought.
- HMRC says closely linked agreements may be one bargain.
Scroll down for the full analysis.
Read the original guidance here:
Stamp duty where you buy land with a building contract
Buying a plot and arranging for the seller to build or improve it can change the amount used to work out stamp duty land tax. The key question is whether you are buying land as it stands or, as part of one package, land together with completed work that the arrangement provides. That is the basic distinction.
What this rule is about
People often divide a deal into a land contract and a building contract, with each document appearing to cover a different part of the overall arrangement. Sometimes that split is genuine. If it is, later building costs may not count when working out SDLT.
Names alone do not decide the issue. HMRC says the real commercial deal matters. A separate contract will not automatically keep construction costs outside the SDLT calculation.
This can make a large difference. Yet it turns on the detail of the agreements.
What the official source says
The law has a rule for construction, improvement and repair work. Under that rule, work can stay outside the amount used to work out SDLT only when every required condition is met, including conditions about timing, land and who must do the work. All of them matter.
- The builder must do the work after the transaction’s effective date.
- The work must be on land you buy under that transaction, or land you already hold.
- The deal must not require the seller, or someone connected with the seller, to do the work.
- If a condition fails, the value of that work counts in the SDLT amount.
HMRC’s manual then considers a common situation: you take ownership before work starts, or while it remains unfinished. HMRC says the normal starting point is that you bought the land in its state on that date.
That usually includes the land price and the value of work already done. It does not normally include work still to come, provided the statutory conditions hold.
What this means in practice
The paperwork needs to match the real deal. A land sale and a later construction job may stand apart. But agreements that depend on each other can point the other way.
- Read both contracts together, not one at a time.
- Check whether either contract can complete without the other.
- Check what happens if either side defaults.
- Identify work finished before you take ownership.
- Keep a clear and realistic split of the total price.
HMRC says that two agreements may be too closely tied to complete independently. For example, this may happen where a default under one agreement stops the other agreement being enforced.
In that situation, HMRC’s view is that, where the agreements are so connected that neither can truly stand alone, the land deal concerns land with completed work. That is HMRC’s starting point. It would treat the full combined price as the starting point.
How to analyse it
Start with the facts, then test them against the contracts. Do not begin with the labels the parties chose.
- What land or property did you receive on the transfer date?
- How much work had the seller completed by then?
- Who agreed to do the remaining work?
- Must the seller do it under the land deal?
- Could either agreement end or fail without affecting the other?
- Do the documents make the land sale conditional on the building work?
- Does the price split fairly reflect land, completed work and later work?
Where one package covers several things, the legislation requires a just and reasonable split. You cannot simply choose a low figure for the land and treat the rest as building cost.
What actually decides it? The bargain you made, viewed as a whole.
Example
Imagine Priya agrees to pay £400,000 in total. £300,000 relates to a plot. Before she takes ownership, the seller completes groundwork worth £25,000. A further £75,000 of building work will happen later.
If the later work meets all the statutory conditions, the amount used to work out SDLT would normally include £325,000: the plot and the work already done. The later £75,000 would not count.
Now change one fact. If Priya’s land contract requires that same seller to complete the £75,000 work, and the two contracts function as a single bargain rather than independently, the statutory exclusion may not apply. That changes the analysis. If both contracts also operate as one inseparable bargain, HMRC says the full £400,000 may count.
Why this can be difficult in practice
This is the part people get wrong. A separate invoice, or even a separate contract, does not by itself establish that you bought only bare land when the surrounding terms show that the transactions were commercially linked. The substance matters.
Equally, using the same seller does not automatically mean every future building cost counts. The timing of the work and the legal links between the agreements matter.
- Cross-default clauses can show that the agreements depend on each other.
- Conditional completion clauses can matter even if prices appear separate.
- Work may have started before transfer but still be hard to value.
- A price split needs support from the real commercial facts.
- HMRC’s view about one bargain is guidance, rather than the law itself.
Keep the contracts, specifications, invoices and evidence of when work happened. Those documents explain what you actually bought.
Key takeaways
- Later building work can stay outside SDLT, but only if every statutory condition is met.
- Work already completed when you take ownership may count in the SDLT amount.
- Separate contracts may still form one bargain if they are tightly linked.
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 43 — what forms the subject of a land transaction
- FA 2003 section 50 — schedule 4 rules for amounts paid on transactions
- FA 2003 Schedule 4 para 1 — amount given for the transaction’s subject matter
- FA 2003 Schedule 4 para 4 — fair splitting of payment between different matters
- FA 2003 Schedule 4 para 10 — when building work counts in the SDLT amount
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 simple rule for deciding when separate contracts are so interlocked that they form one bargain. The wording, default clauses and commercial reality matter.
- A stated split between land and works does not settle the SDLT position if it does not fairly reflect the bargain.
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 land sale contract and the building contract
- Any cross-default, termination or conditional-completion clauses
- The completion and effective dates
- Invoices, valuation evidence and a breakdown of work completed before transfer
- Evidence showing how the total price was split
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 where you buy land with a building contract [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 43 - what forms the subject of a land transaction https://www.legislation.gov.uk/ukpga/2003/14/section/43/2025-11-17 - FA 2003 section 50 - schedule 4 rules for amounts paid on transactions https://www.legislation.gov.uk/ukpga/2003/14/section/50/2025-11-17 - FA 2003 Schedule 4 para 1 - amount given for the transaction's subject matter https://www.legislation.gov.uk/ukpga/2003/14/schedule/4/paragraph/1/2025-11-17 - FA 2003 Schedule 4 para 4 - fair splitting of payment between different matters https://www.legislation.gov.uk/ukpga/2003/14/schedule/4/paragraph/4/2025-11-17 - FA 2003 Schedule 4 para 10 - when building work counts in the SDLT amount https://www.legislation.gov.uk/ukpga/2003/14/schedule/4/paragraph/10/2025-11-17 Guidance page from HMRC on this topic (guidance, not law): https://www.gov.uk/hmrc-internal-manuals/stamp-duty-land-tax-manual/sdltm04015 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 simple rule for deciding when separate contracts are so interlocked that they form one bargain. The wording, default clauses and commercial reality matter. - A stated split between land and works does not settle the SDLT position if it does not fairly reflect the bargain. 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: Stamp duty where you buy land with a building contract
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