Remortgaging a rental
Remortgaging a rental property means replacing the existing mortgage on a buy-to-let property with a new deal, either with the same lender (a product transfer) or a new one (a full remortgage). The two routes are legally distinct: a product transfer is a variation of the existing charge and typically involves no legal fees, no valuation, and a simpler process; a full remortgage involves redeeming the existing charge and registering a new one, requiring a solicitor and usually a valuation. For landlords whose current fixed rate is ending, a product transfer is frequently the faster and cheaper route if the same lender offers competitive terms, but it forfeits the ability to shop the whole market.
Why landlords remortgage
The most common trigger is the expiry of a fixed-rate product. A landlord who does not act before the end of the fixed term reverts to the lender's standard variable rate (SVR), which is almost always materially higher. Other reasons include releasing equity to fund a further purchase or capital expenditure, reducing the loan term, switching from repayment to interest-only (or the reverse), and changing ownership structure, most commonly, transferring from personal ownership to a limited company to access better ICR thresholds and mitigate the mortgage interest restriction introduced by Section 24 of the Finance Act 2015.
The ICR stress test
Most buy-to-let lenders do not assess BTL remortgage affordability against the borrower's personal income in the same way as a residential mortgage. Instead, they use an interest coverage ratio (ICR) stress test: the expected monthly rental income must equal at least 125% of the stressed mortgage interest payment, where the stressed rate is typically the product pay rate plus a buffer. Higher-rate taxpayers face a stricter threshold, commonly 145%, because Section 24 has restricted the mortgage interest relief available, increasing tax liability on gross rental income.
The stress rate used and the ICR threshold vary by lender and product type. For 5-year fixed products, many lenders now stress at the actual pay rate rather than a separate notional rate, which can materially improve affordability headroom compared with 2-year products. August's free buy-to-let mortgage calculator models ICR and DSCR stress tests against rental income so landlords can assess borrowing headroom before approaching a lender or broker.
The PRA's supervisory statement on buy-to-let underwriting (SS13/16, Bank of England) sets the minimum standards lenders must apply when assessing BTL mortgage affordability. All regulated lenders must comply with it.
Portfolio landlord rules
Landlords with four or more distinct mortgaged buy-to-let properties are assessed as portfolio landlords under PRA guidelines, meaning lenders evaluate the whole portfolio rather than only the subject property. A remortgage application in this category typically requires a property schedule covering all portfolio assets, including addresses, current values, outstanding mortgage balances, rents, and void history, as well as evidence of how the portfolio is managed. Lenders apply a background portfolio ICR test that considers the total rental income and total mortgage debt across all properties, not only the one being refinanced.
What lenders typically require
For a standard single buy-to-let remortgage, lenders will generally ask for: the current tenancy agreement and evidence of rental payments; proof of rental income (usually three to six months of bank statements); a mortgage statement for the existing loan; identification and, for the property address, a recent valuation. Self-employed borrowers or those with complex income will also need SA302 forms and HMRC tax year overviews. For leasehold flats, the lender may require an EWS1 form where there are concerns about external wall construction or cladding.
Costs
Remortgaging carries costs that must be weighed against the projected saving. These typically include an arrangement or product fee (commonly £999–£2,999, sometimes added to the loan), a valuation fee, and, for a full remortgage to a new lender, legal fees. An early repayment charge (ERC) may apply if switching during a fixed-rate period; ERCs on BTL products commonly range from 1% to 5% of the outstanding balance. A product transfer with the existing lender avoids legal fees and may waive the valuation, but ERC terms still apply if the fixed period has not expired.
The Renters' Rights Act 2025 and the remortgage risk backdrop
The Renters' Rights Act 2025, in force from 1 May 2026, has altered the risk assessment lenders apply to buy-to-let remortgage applications in England. With Section 21 no-fault possession abolished and all private tenancies operating as open-ended assured periodic tenancies, the timeline to regain vacant possession in the event of arrears or breach is longer and more procedurally structured than before. Lenders now factor this extended possession risk into their underwriting: a property with a problem tenancy may take considerably longer to recover, and some lenders have begun requiring evidence of compliance with post-RRA obligations, correct notice forms, EPC ratings at minimum Band E, deposit protection, and Right to Rent checks, as part of the remortgage application process.
From working with self-managing landlords across the UK, the practical implication is that clean compliance documentation has become part of the remortgage pack. A landlord who cannot promptly produce a valid gas safety certificate, a current EICR, and the correct tenancy documentation may face delays in the underwriting process that cost more in SVR payments than a more proactive approach would have done.
For landlords considering whether to remortgage into a limited company structure to access better ICR thresholds or mitigate Section 24 exposure, see the August guide to forming a limited company as a landlord.
Frequently asked questions
What is the difference between a product transfer and a remortgage?
A product transfer means switching to a new deal with the same lender. No new legal charge is registered, so there are typically no legal fees and no formal valuation is required, making it faster and cheaper than a full remortgage. A full remortgage involves switching to a new lender, which requires legal work to redeem the existing charge and register a new one. The trade-off is that a product transfer limits you to one lender's product range, while a full remortgage opens the whole market.
What LTV do buy-to-let lenders typically require?
Most buy-to-let lenders require a maximum LTV of 75%, meaning at least 25% equity in the property. Some specialist products are available up to 80% LTV, but rates and ICR requirements are typically less favourable at higher LTV. The LTV calculation uses the lender's own valuation, not the landlord's estimate.
How does Section 24 affect buy-to-let remortgage calculations?
Since April 2020, individual landlords can no longer deduct mortgage interest as an expense before calculating taxable rental profit. Instead, they receive a basic rate tax credit (20%) against finance costs. Higher-rate taxpayers effectively pay income tax on the gross rental income and receive only a 20% credit. This increases the tax cost of borrowing, which lenders reflect by applying a stricter ICR threshold, commonly 145% instead of 125%, for applicants taxed above the basic rate.
Does remortgaging trigger stamp duty or capital gains tax?
No. A straightforward remortgage (replacing one mortgage on the same property with another) does not trigger a stamp duty or capital gains tax event. The property does not change hands. However, if the remortgage is part of a transfer of the property into a limited company, both SDLT and potentially CGT could arise, those structures require specialist advice.
