Can You Borrow More on Your Mortgage to Renovate?

Plenty of buyers do what families have always done: take on a slightly bigger mortgage when they buy, with the quiet intention of spending some of it on doing the place up. A new kitchen, a boiler that won't give up in January, knocking two rooms into one. It's a sensible instinct — borrow while the money is secured against the home and repaid gently over decades, rather than reaching for a credit card the day the radiators pack in.

But the mechanics rarely work the way people picture them. You generally can't just ask a lender for "the purchase price plus £20,000 for renovations" on a standard residential mortgage. Here's how borrowing to renovate actually works in 2026 — at the point of buying and afterwards — what it genuinely costs once you spread it over the term, and how to weigh it up before you commit.

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Can you add renovation costs to a purchase mortgage?

The short answer is: not directly, and not on a standard residential mortgage. A lender lends against the property — specifically against the lower of the price you're paying and the surveyor's valuation — up to their maximum loan-to-value (LTV). If you're buying a £200,000 home, the loan is sized against that £200,000, not £220,000 because you'd like a £20,000 kitchen. The bricks are the security, and a lender won't hand over more than the bricks are worth.

So the familiar picture of "taking a bigger mortgage and spending the extra on the house" usually isn't a single larger loan with a renovation pot bolted on. What's actually happening is one of a few different routes — and it's worth knowing which one you're on, because they cost different amounts and carry different risks.

What's really happening: a higher LTV frees your cash

The most common version — and probably what you've seen friends or family do — is borrowing at a higher LTV so you keep more of your own savings free for the work.

Say you have £40,000 in cash and you're buying a £200,000 home. You could put the full £40,000 down as a 20% deposit and borrow £160,000. Or you could put down £20,000 (a 10% deposit), borrow £180,000, and keep £20,000 back to spend on renovations. The mortgage isn't "funding the kitchen" — but by borrowing more against the property, you've freed your own cash to do it.

That's a genuine, widely-used strategy, but it isn't free. A higher LTV almost always means a higher interest rate (lenders price 90% lending above 80% lending), a smaller equity cushion if prices dip, and more interest paid across the term. You're effectively financing the renovation at your mortgage rate, stretched over 25 or 30 years — which, as the worked example below shows, costs a great deal more than the sticker price of the work. To see what different deposit sizes do to your borrowing, read how much you can borrow on your salary.

Renovation and refurbishment mortgages

For properties that need real work — an uninhabitable doer-upper, or a project that adds significant value — there are more specialist products. Renovation or refurbishment mortgages, often from specialist lenders or via short-term bridging finance, can lend partly against the property's projected value after the works, or release funds in stages as the project progresses.

These are more complex, usually more expensive, and almost always arranged through a broker who knows the specialist market. They suit buyers taking on a property a mainstream lender won't touch in its current state — not someone who simply wants a new bathroom in an already-liveable home. If that's your situation, a whole-of-market broker is the right first call, because the criteria vary enormously between lenders.

After you've bought: further advances and remortgaging

If you're already in the home and want to fund improvements, you've got equity to work with, and three main routes:

• A further advance — borrowing more from your existing lender, secured on the property, on top of your current mortgage. Subject to affordability and your LTV, it's often the simplest option if your lender offers a competitive rate.
• Remortgaging to release equity — switching to a new, larger mortgage that frees up cash, ideally timed to when your current deal ends so you avoid early repayment charges.
• A second-charge mortgage — a separate secured loan that sits behind your main mortgage, sometimes used when remortgaging the whole balance isn't attractive (for example, if you're on a very low fixed rate you don't want to lose).

All three are secured against your home and are FCA-regulated borrowing, so the same warning applies as to any mortgage: miss the payments and the home is at risk. A broker can compare a further advance against a full remortgage to see which is genuinely cheaper for your circumstances, rather than just the one your current lender happens to offer.

Where the money goes — and where it pays back

Renovation budgets cluster around a few big-ticket items: kitchens, bathrooms, extensions, and — less glamorous but often the most worthwhile — the things that affect how much the home costs to run. A failing boiler, thin insulation or single glazing quietly drains money every month, and increasingly affects a property's value and mortgageability too. A home's energy efficiency (its EPC rating) is something lenders and buyers pay attention to, and a growing number of "green" mortgage deals reward more efficient homes with better rates.

So replacing an ageing boiler or adding solar isn't only about comfort — it lowers running costs and can support the home's value, which matters when the works are being funded by borrowing against that same home. If you're costing up this kind of work as part of your borrowing plan, get fixed quotes early so the figure you borrow against is realistic rather than a guess that balloons halfway through the job.

It's also worth budgeting for the disruption itself. A major renovation often means living elsewhere for a stretch, or clearing rooms and storing furniture while the work happens — costs that are easy to forget when you're focused on the headline price of a kitchen.

What it actually costs to borrow for renovations

Spreading a renovation over your mortgage term is the part people underestimate. Because the borrowing is repaid over 25 or 30 years, the interest stacks up well beyond the cost of the work itself.

Take £20,000 of works added to your mortgage borrowing at, say, 5% over a 25-year term. The monthly cost is modest — around £117 — which is exactly why it feels so affordable. But over the full term you'd repay roughly £35,000 in total: about £15,000 of interest on top of the £20,000 you actually spent. (Rates and terms vary, so treat this as an illustration rather than a quote — run your own figures through the calculators.)

That doesn't make borrowing to renovate wrong. Sometimes it's the only realistic way to make a home liveable, and a £117-a-month uplift may be entirely manageable against the value and comfort the work adds. But it reframes the decision honestly: a £20,000 kitchen financed this way is really closer to a £35,000 kitchen. Where you can, overpaying to clear the renovation portion faster — or keeping it on a shorter, separate facility rather than your full 25-year term — saves a large slice of that interest.

The risks worth weighing

• It's debt secured on your home. Funding a kitchen on a credit card is unsecured; funding it through your mortgage puts the home itself on the line if you can't keep up.
• A higher LTV costs more. Borrowing more against the property usually nudges you into a worse rate band and thins your equity cushion if prices fall.
• Renovation budgets overrun. They almost always do. Borrow with a contingency built in, and avoid stretching to your absolute affordability ceiling — you want headroom, not a knife-edge.
• You won't always get the spend back. Over-improving for the street, or sinking money into work that doesn't add value, means the renovation costs you twice — once in cash and again in interest.
• It can crowd out your buying budget. Money freed for renovations is money not going into your deposit, which can mean a higher rate on the whole loan.

Getting it right

If doing up the home is part of your plan, build it into the conversation from the start rather than bolting it on afterwards. Work out the realistic cost of the works with actual quotes; decide whether to fund it by borrowing at a higher LTV at purchase, a specialist renovation product, or a further advance once you're in; and get a broker to price those routes against each other. Run the purchase numbers through the affordability calculator, and read how much you can borrow and the full cost of buying a house so the renovation sits on top of a budget you genuinely understand.

The short version: you can't simply inflate a purchase mortgage to cover renovations, but borrowing at a higher LTV to free your own cash, a renovation mortgage for a project property, or a later further advance or remortgage all get you there — each at a real, term-long cost. The goal is a home you can comfortably afford to both own and improve, not a beautiful kitchen attached to a mortgage that keeps you awake at night.