Buy to Let Remortgage UK 2026, A Landlord's Complete Guide

Product transfer vs full remortgage: the key difference

When your BTL deal expires, you have two fundamental options:

• Product transfer (PT): You switch to a new rate product with your existing lender without going through a full application process. Typically involves no new affordability assessment, no new valuation, lower fees (often fee-free or small admin charge), and faster processing (days rather than weeks). The rate may be slightly higher than a full remortgage with a competitor
• Full remortgage: You switch to a new lender entirely or to a new product with your existing lender that requires a full application. Involves a new affordability/ICR assessment, property valuation, solicitor involvement, and standard arrangement fees (typically £995-£2,000). Takes 4-8 weeks. Often achieves a lower rate but higher total cost if arrangement fees are factored in
• When a product transfer is better: Your rental income barely clears the stress test at current rates, your property value has fallen or you have insufficient equity for a new lender's LTV requirements, you want speed and certainty, or the total cost of switching (fees + rate difference) does not justify moving
• When a full remortgage is better: Rates from new lenders are materially lower, your property has increased in value allowing a lower LTV tier (and therefore better rate), you want to increase borrowing to release equity, or you are restructuring to a different loan type (e.g., interest-only to repayment or vice versa)

BTL stress test and ICR calculations in 2026

Unlike residential mortgages where affordability is based on personal income, BTL mortgages use an Interest Coverage Ratio (ICR) stress test:

• What the ICR stress test is: Lenders calculate whether the rental income is sufficient to cover the mortgage interest at a stressed rate with an appropriate buffer. The standard formula is: Rental income must be at least X% of monthly interest at the stressed rate
• Typical ICR requirements in 2026: For basic-rate taxpayers, most lenders require rental income at 125-130% of interest payments. For higher-rate or additional-rate taxpayers (because Section 24 reduces their after-tax income from rent), many lenders now apply 145% coverage to account for the additional tax burden
• Stressed rate: Lenders do not use the actual deal rate for ICR calculations. They use a stressed rate, typically 5.5-7% (check each lender's current stressed rate). This means a low-rate deal does not automatically pass the ICR test; the calculation uses a notional higher rate
• Example: A £200,000 interest-only BTL mortgage. Monthly interest at 5.5% stressed rate = £917. At 125% ICR: rental income must be at least £1,146/month. At 145% ICR: rental income must be at least £1,330/month. If your rent is below this, your borrowing options are restricted
• Top-slicing: Some lenders allow 'top-slicing' where the landlord's personal income is used to supplement rental income that falls slightly short of the ICR threshold. This is discretionary and varies by lender

Section 24 impact on your BTL remortgage capacity

Section 24 (the finance cost restriction for individual landlords) directly affects BTL remortgage affordability:

• What Section 24 does: From 2020/21 onwards, individual landlords can no longer deduct mortgage interest as an expense against rental income. Instead, they receive a basic-rate tax credit (20%) on mortgage interest costs. Higher-rate taxpayers effectively pay tax on 'phantom income', as their rental profit is calculated before deducting mortgage interest
• Impact on cashflow: A higher-rate landlord with a £200,000 mortgage at 5% (£10,000/year interest) can no longer deduct this from rental income. They pay income tax at 40% on the full rental income, then receive a 20% credit on the £10,000 interest. Net tax cost is 20% of £10,000 = £2,000 more per year compared to the pre-2020 position
• Impact on remortgage stress tests: Because Section 24 reduces the after-tax cashflow that pays the mortgage, lenders have responded by requiring higher ICR buffers for higher-rate taxpayers (145% rather than 125%). This reduces how much higher-rate individual landlords can borrow or remortgage at current rents
• Section 24 does not apply to limited companies: A BTL mortgage held in a limited company is not subject to Section 24. The company can deduct mortgage interest as a business expense. This is one of the reasons many landlords are exploring incorporation — though a remortgage to a limited company is a significant step with capital gains and SDLT implications

Remortgaging to a limited company: key considerations

Some landlords facing Section 24 exposure are exploring incorporation — transferring their portfolio into a limited company. Remortgaging as part of incorporation is a significant decision:

• You cannot simply switch your mortgage to a limited company: If the property is in your personal name, it must be legally transferred (sold) to the company. This is a disposal for Capital Gains Tax purposes and may trigger CGT on any gain since purchase. It also attracts Stamp Duty Land Tax (SDLT) on the market value
• Mortgage availability: Not all lenders offer limited company BTL mortgages. The market has grown significantly, with specialist lenders including Foundation Home Loans, Paragon, and Precise offering limited company BTL products, but rates are often 0.25-0.5% higher than personal-name equivalent deals
• SPV structure: Most lenders require the company to be a Special Purpose Vehicle (SPV) with a property investment SIC code (68100 or 68209). Lending to a trading company that also happens to own property is less common and more expensive
• Profit extraction efficiency: While a limited company can deduct mortgage interest, profits must eventually be extracted — either as salary (subject to employer's NIC) or dividends (taxed at dividend rates). The overall tax efficiency depends on your personal income level and dividend allowance
• Take professional advice: The decision to incorporate involves CGT, SDLT, income tax, and mortgage market analysis. A specialist landlord tax adviser and a mortgage broker with limited company BTL expertise should be involved before proceeding

BTL remortgage timeline and process

Follow this timeline to avoid reverting to your lender's SVR:

• 6 months before deal expires: Review your current deal, note the expiry date and any early repayment charges. Begin comparing rates using a whole-of-market BTL mortgage broker. Assess whether a product transfer or full remortgage is the better option
• 4-5 months before expiry: If proceeding with a full remortgage, submit your application. This allows time for valuation, legal work, and any queries. Most lenders will hold an agreed rate for 3-6 months
• 3 months before expiry: If using your existing lender for a product transfer, this is typically when the transfer window opens. Contact your lender directly or via your broker
• 6-8 weeks before expiry: If solicitors are involved, ensure they are instructed and progressing. Provide all required documentation promptly to avoid delays
• At expiry: Confirm the new deal has completed and you are paying the correct new rate. Many SVRs are triggered automatically — check your first payment after the switch

Frequently asked questions