Start with what the remortgage funds
This guide is for individual UK residential landlords refinancing without changing ownership. It reflects the rules checked on 13 November 2026. A company has a separate Corporation Tax regime. When comparing offers, split the loan into amounts that replace existing debt, fund further rental expenditure or release cash for other purposes. The property used as security does not by itself decide the tax treatment.
Trace the old loan and the additional advance
The business-purpose test under ITTOIA 2005 sections 34 and 272 comes before the residential finance-cost restriction. For replacement borrowing, establish what the original loan funded and which balance the new lender redeems. For a top-up, map the actual payments. An advance used directly for private spending normally fails the business-purpose test. If business and private purposes are identifiable within one loan, allocate interest on a supportable basis and update the split as balances change.
Review any proposed replacement of genuine capital introduced separately. HMRC’s BIM45700 guidance illustrates that borrowing to replace capital can qualify in some circumstances even when the owner withdraws cash. Review the business capital position, prior drawings and evidence of the value introduced. A new lender valuation or unused loan-to-value capacity does not establish the amount of capital that can be replaced.
Check the tax reduction after identifying eligible costs
Section 272A restricts deductions for dwelling-related finance costs for individuals. Eligible residential finance costs generally feed into a basic-rate Income Tax reduction rather than reducing rental profit. The calculation is broadly limited by eligible finance costs, property business profits after relevant losses, and adjusted total income for this purpose. Carry forward qualifying amounts where the rules permit. Private interest does not become eligible simply because a cap applies. Separate interest, loan fees and capital repayments: principal is not a finance cost for this calculation, and eligible fees need their own review.
Hypothetical example: one loan, two uses
Assume a £250,000 interest-only loan at a uniform 5% replaces £200,000 of qualifying residential business borrowing and funds £50,000 of direct private spending. Assume the private amount does not replace capital introduced, balances stay constant for a full year, there are no fees or brought-forward costs, and the two uses are evidenced. Annual interest is £12,500, of which £10,000 relates to the rental business and £2,500 is private.
If the relevant property profit is £8,000 and the income limit does not bind, the reduction is £1,600 at 20%. In this example £2,000 of eligible finance costs can carry forward; the £2,500 of private interest cannot. The owner still pays the full £12,500 to the lender. These figures illustrate the mechanism and are not a tax bill or client case.
Agree the split before drawing the money
Gather the original loan statements, redemption figure, offer, completion statement and intended uses. Keep a dated allocation of advances and repayments and the underlying invoices or bank transfers. Compare the after-tax cost of each option, including fees and early repayment charges. Ask for bespoke advice before drawing funds if the loan spans several properties, earlier withdrawals are unclear or a capital withdrawal is planned.
UA Tax advises landlords in London and across the UK. Book a Tax Consultation to review the proposed loan and its after-tax cash cost.
For advice on your own circumstances, see our property tax planning service and agree the scope before acting.
Official sources and further reading
These primary sources support the framework above. Check the current version before acting because tax law and HMRC guidance can change.