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    UK Mortgage Guide

    Remortgage Residential to Buy-to-Let UK 2026

    Turning your current home into a buy-to-let is one of the most common UK property strategies — relocating for work, upsizing for a growing family, or starting a portfolio. But the financing has to be done right. Letting on a residential mortgage without consent is a breach; full BTL remortgaging brings different rates, deposits and stress tests. This guide explains every UK route in 2026 — consent-to-let, full BTL remortgage, and let-to-buy.

    First Rung Now Editorial Updated 15 June 2026 7 min read

    The three routes explained

    Ask your existing residential lender for permission to let the property short-term. Typical scenarios: a temporary job relocation, marrying and moving into a partner's home, struggling to sell.

    • Fee: usually £100–£250 (some lenders free).
    • Rate: usually same as residential, or +0.50% (lender-specific).
    • Duration: typically 12 months, renewable. Some lenders cap at 24 months.
    • No ICR test usually applied.
    • Quick to arrange (1–2 weeks).

    2. Full BTL remortgage

    You move the mortgage to a BTL product with a specialist BTL lender. Required if you plan to let permanently.

    • BTL rate (5.30%–5.80% at 75% LTV in 2026).
    • Standard ICR test (125%–145% at 5.5%–7% stress).
    • Arrangement fee 1%–2%.
    • Lender wants confirmation of intention to let, rental valuation, and (usually) AST in place.
    • 4–6 week process.

    3. Let-to-buy (paired transaction)

    You BTL-remortgage your current home AND buy a new residential simultaneously. Both completions same day.

    • Existing home: BTL mortgage. Equity released as deposit on new home.
    • New home: standard residential mortgage.
    • Lender for the new residential treats the existing BTL as a self-funding liability — provided rental coverage is strong.
    • SDLT: 5% surcharge on the new home because you own two properties on completion day.

    Worked let-to-buy example

    Current home £350k, mortgage £180k, equity £170k. Target new home £450k.

    • Step 1: BTL remortgage current home at 75% LTV = £262,500. Repay £180k existing. Net cash released: £82,500.
    • Step 2: Use £82,500 as deposit on new £450k home (18% deposit). New residential mortgage £367,500 (82% LTV).
    • Step 3: Rent old home at £1,500/month — must cover ICR at 145% of stressed BTL interest (£262.5k × 7% ÷ 12 × 145% = £2,219). £1,500 fails ICR — reduce BTL loan to ~£175k.
    • This is the ICR squeeze that kills many let-to-buy plans — pre-test it carefully.

    UK lenders for residential-to-BTL remortgages

    • Consent-to-let leaders: Halifax, Nationwide, Santander, Barclays, NatWest — all offer CTL for residential customers.
    • Full BTL remortgage: The Mortgage Works, Paragon, Kent Reliance, Landbay, Foundation, Precise, BM Solutions, Aldermore.
    • Let-to-buy specialists: Coventry BS, Skipton BS, Accord, NatWest, Barclays — offer paired BTL + residential transactions.

    SDLT planning for let-to-buy

    • You pay the 5% surcharge on the new residential because you own two properties on completion day.
    • You can reclaim the surcharge if you sell the old property within 3 years.
    • In a true let-to-buy you're keeping the old home — so the surcharge stays.
    • Worked: £450k new home SDLT with surcharge = £35,000. Without surcharge = £12,500. Surcharge cost = £22,500.

    Tax considerations

    • Old home becomes a BTL — rental income taxable at marginal rate, mortgage interest restricted under Section 24 if held personally.
    • Future sale of old home: CGT applies on the period it was rented (your main residence relief is pro-rated).
    • Some let-to-buy landlords transfer the old home to an SPV — but this triggers CGT and SDLT immediately.

    Pros

    • Lets you keep a property and build portfolio while moving on.
    • Equity release funds new home deposit.
    • Multiple UK lenders offer dedicated let-to-buy products.
    • Consent-to-let suits short-term lets without full remortgage.
    • Rental income can cover BTL mortgage with surplus.

    Cons

    • BTL ICR test can force loan reduction (capital injection needed).
    • 5% SDLT surcharge on new residential property.
    • Section 24 hits personal-name BTL landlords.
    • CGT applies on future sale of let property (proportionate).
    • Two mortgages = higher overall risk if either property underperforms.

    Frequently asked questions