/
Essential cookies always run. Accepting also enables Google Analytics and Microsoft Clarity. No advertising cookies — see our privacy policy.
A second charge buy-to-let loan lets a landlord borrow against the equity in a rental property while keeping the existing buy-to-let mortgage. See how lenders test the rent, when the first lender's consent is needed and how these loans are regulated.
Reviewed by David Sampson, Founder & Director · Created 19 October 2026 · Last reviewed 19 October 2026
TL;DR
A second charge buy-to-let loan is borrowing secured on a rental property behind its existing buy-to-let mortgage. Landlords use it to raise money for deposits, refurbishments or other investments without remortgaging, often when the first mortgage has a good rate or early repayment charges. The rent and the equity both shape what can be borrowed.
A second charge buy to let mortgage works like any second charge: the existing lender keeps the first charge, the new lender registers its charge behind it, and you make two monthly payments. On a sale, the first lender is repaid first. The main differences from a residential second charge are how the lender tests affordability and how the loan is regulated.
BTL second charge loans are offered by a smaller group of specialist lenders, and some lend only to experienced landlords or limited companies. For how second charges work on homes, including the FCA rules that apply there, see the guide to second charge mortgages.
Lenders check that the rent covers the payments on both loans with a margin, usually tested at a stressed interest rate. They also look at the combined loan to value, your experience as a landlord, your wider portfolio and the property's condition. Limited company and personal borrowers are assessed on different tax positions.
The Bank of England's underwriting standards for buy-to-let, PRA SS13/16, set out the interest cover approach most lenders use: the rent must exceed the interest by a set ratio at a stressed rate. On a second charge the test covers the first mortgage and the new loan together, which often limits the amount more than the equity does.
For example, a flat letting at £1,200 a month with a first mortgage costing £500 a month at the stress rate leaves less room than the equity suggests: at a 125% cover ratio, the rent supports total stressed payments of £960, so the second loan's stressed payment can be no more than £460 (example figures, not market data).
Criteria differ widely between second charge buy-to-let lenders, on cover ratios, maximum combined loan to value, portfolio size and whether they lend to limited companies, so compare them before you apply.
Many buy-to-let mortgage terms require the first lender's consent before a second charge is registered. Some lenders refuse, and borrowing without consent can breach the mortgage terms. Check your mortgage conditions first. If consent is unlikely, a further advance from the first lender or a remortgage may be the only routes.
A further advance on a buy to let mortgage keeps one lender and one charge, but the lender reassesses the rent and the loan to value on the higher balance. The guide to consent to a second charge explains how charges are registered and ranked, and what a postponement or restriction means for a sale.
Most buy-to-let second charges are business lending and fall outside FCA mortgage regulation. Consumer buy-to-let, such as letting an inherited former home, has its own lighter regime, and a loan secured on a property you or a close relative will live in is regulated. Protections differ, so check how a lender classifies the loan.
The consumer buy-to-let regime comes from the Mortgage Credit Directive Order 2015 and covers accidental landlords who did not buy the property as a business. Business buy-to-let lending, including most loans to portfolio landlords and limited companies, is not regulated, so there is no automatic access to the Financial Ombudsman Service for those loans (FCA Handbook PERG 4, accessed 19 Oct 2026).
Compare a buy-to-let second charge with a further advance, a remortgage across the portfolio and short-term bridging, on total cost and how long you need the money. A broker who handles landlord cases can compare these side by side. Ask for a dated illustration covering the rate, fees, rent test and total repayable.
If the money is for another purchase, the new property's own mortgage matters as much as the second charge. Lenders for buy-to-let mortgages look at the deposit's source, so check that money raised on a second charge is accepted before you rely on it.
Yes. Specialist lenders offer second charges behind an existing buy-to-let mortgage, assessed on the rent, the combined loan to value and your experience as a landlord. Many first lenders' terms need their consent before a second charge is registered, so check your mortgage conditions first.
Often, yes. Many buy-to-let mortgage terms say the lender must consent before another charge is registered, and some refuse. Borrowing without consent can breach the terms of the first mortgage. If consent is unlikely, a further advance or a remortgage may be the options to compare.
They test whether the rent covers the payments on both the first mortgage and the second charge by a set ratio, at a stressed interest rate, following the approach in PRA SS13/16. The combined test often limits the loan more than the equity does, so the rent level matters.
Yes, some lenders lend second charges to limited company landlords, usually with personal guarantees from the directors. Rental cover tests can differ for companies because of the way interest is taxed. Check each lender's criteria on company structure, experience and the first lender's consent.
Usually not. Most buy-to-let second charges are business lending and fall outside FCA mortgage regulation. Consumer buy-to-let, such as letting a former home you inherited, has its own lighter regime, and a loan on a property you or a close relative will live in is regulated.
Landlords use them to raise deposits for further purchases, fund refurbishments, pay tax bills or release equity for other investments, without disturbing the first mortgage. Lenders check the purpose, and some restrict uses, so confirm that what you plan is accepted before you apply.
Important: Your home may be repossessed if you do not keep up repayments on your mortgage. Information on this page is for general guidance only and does not constitute financial advice.Always verify details directly and seek independent advice before making financial decisions.