Do you pay SDLT when adding a spouse to the title and mortgage after a remortgage?

Introduction

A common question is whether Stamp Duty Land Tax (SDLT) is payable when one spouse already owns a home and later adds the other spouse to both the legal title and the mortgage. People often assume that, because no cash is being paid between them, the transfer can simply be treated as a gift. In many cases, however, SDLT can still arise if the incoming spouse takes on responsibility for part of the mortgage debt.

The Question

The situation can be put like this. One spouse owns a residential property. The property is being remortgaged, additional borrowing is being taken out, and the other spouse is to be added to both the mortgage and the title with a 50% share. The incoming spouse is not currently earning and may not be contributing to the mortgage repayments. The question is whether the transfer can be treated as a gift, or whether SDLT is payable because of the mortgage being assumed.

Nick’s Explanation

Nick’s key point was that SDLT is not only charged where money changes hands. It can also be charged where a person takes on liability for mortgage debt as part of a transfer of property.

In anonymised form, his explanation was:

“Even though no money is changing hands, HMRC treats the assumption of mortgage debt as chargeable consideration. If a spouse is added to both the title and the mortgage, and takes on 50% of the total mortgage debt, SDLT is calculated on that share of the debt.”

He also explained that a transfer between spouses can be a gift for SDLT purposes only where no mortgage liability is being transferred. Once the incoming spouse assumes part of the mortgage, that assumed debt is treated as consideration.

Using the figures provided, if the remortgaged loan is about £1,257,000 and the incoming spouse takes on 50% of that debt, the chargeable consideration would be about £628,500. On ordinary residential SDLT rates, that would produce SDLT of £21,425.

The Law

The main legislation is the Finance Act 2003.

SDLT is charged on land transactions where there is “chargeable consideration”. Chargeable consideration is defined broadly and is not limited to cash. It includes money’s worth and the assumption of debt in connection with the transfer.

Where a property is transferred subject to an existing mortgage, or where the transferee enters into mortgage liability as part of the transaction, HMRC generally treats the debt taken on as chargeable consideration.

For transactions between spouses or civil partners, there is no general rule saying that all transfers are automatically exempt from SDLT. A transfer for no consideration may fall outside the charge, but if the transferee assumes liability for mortgage debt, that debt can create chargeable consideration and therefore an SDLT liability.

First-time buyer relief is also limited by the amount of chargeable consideration. If the relevant consideration exceeds the statutory threshold for the relief, the relief is not available.

Analysis

The analysis usually works in the following order.

First, identify what is actually being transferred. Here, the incoming spouse is receiving a 50% interest in the property and is also being added to the mortgage.

Second, ask whether there is any chargeable consideration. If the transfer were a pure gift with no mortgage and no debt assumed, there would usually be no SDLT because there would be no chargeable consideration. But that is not the case here.

Third, identify the mortgage debt being assumed. If the new mortgage after remortgage is about £1,257,000, and the incoming spouse becomes jointly liable for half, the assumed debt is about £628,500.

Fourth, calculate SDLT on that figure using the residential rates in force for the transaction. On the figures given in the original explanation:

• £0 to £125,000 at 0% = £0
• £125,001 to £250,000 at 2% = £2,500
• £250,001 to £628,500 at 5% = £18,925

Total SDLT: £21,425.

That means a figure of £19,500 would not be correct on those assumptions. The final SDLT would depend on the actual amount of debt taken on at completion and the rates in force at that time, but on the numbers provided the calculation comes out higher.

Fifth, consider whether the transfer can still be described as a gift. In ordinary language, spouses may think of this as a gift of equity. But for SDLT, the legal question is whether there is chargeable consideration. If the incoming spouse assumes mortgage debt, HMRC will usually treat that as consideration, so the transfer is not free of SDLT merely because no cash is paid between the spouses.

Sixth, consider first-time buyer relief. If the chargeable consideration is above the relevant threshold, the relief is not available. On the figures discussed, that relief would not assist.

Finally, affordability is a separate issue from SDLT. Whether a lender will include the incoming spouse in affordability checks is a mortgage underwriting question rather than a tax question. In practice, if a person is being added to the mortgage, the lender will usually consider the financial position of all borrowers under its own lending criteria.

Outcome

If a spouse is added to both the title and the mortgage, and takes on part of the mortgage debt, SDLT is usually payable on the share of debt assumed. On the figures discussed here, the chargeable consideration would be about £628,500 and the SDLT would be about £21,425 under the residential rates used in Nick’s explanation.

It is therefore unlikely to be treated as a no-SDLT gift if the incoming spouse is also being added to the mortgage.

Practical Steps

If you are assessing a similar transaction, the sensible steps are:

• Confirm the exact mortgage balance that will exist immediately after the remortgage completes.
• Confirm whether the incoming spouse will become jointly liable for the whole mortgage or treated as taking on a specific share of it.
• Calculate the chargeable consideration by reference to the debt assumed, not just any cash paid.
• Check the SDLT rates and reliefs in force on the effective date of the transaction.
• Ask the conveyancer to confirm the SDLT filing position before completion.
• Ask the lender or mortgage broker separately about affordability, because that is a lending issue rather than an SDLT issue.

Conclusion

Adding a spouse to a property title can trigger SDLT if that spouse also takes on mortgage debt. The transfer may be a gift in family terms, but for SDLT the assumed debt is usually chargeable consideration. In a remortgage-and-transfer case, the key figure is normally the share of mortgage liability being taken on.

Legal References Used

• Finance Act 2003
• Finance Act 2003, provisions on chargeable consideration
• Finance Act 2003, provisions relevant to transfers subject to debt or mortgage liability
• Finance Act 2003, first-time buyer relief provisions

This page was last updated on 22 March 2026.

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