Funding a House Extension in 2026: Further Advance, Remortgage or Personal Loan?
A house extension is one of the larger sums homeowners borrow for, which makes the funding route — secured against the home or unsecured — a genuinely significant decision, not just a rate comparison.
Comparing the Main Funding Routes
| Option | Security | Typical Rate | Typical Term |
|---|---|---|---|
| Further advance | Secured against home | Often lower | Mortgage-length |
| Remortgage | Secured against home | Often lower | Mortgage-length |
| Personal loan | Unsecured | Often higher | Shorter, fixed |
Remortgage Calculator
Compare your current mortgage deal with a new rate to see monthly savings, total interest saved, and whether remortgaging makes sense.
Open Remortgage calculatorFees That Change the Comparison
Arranging a further advance or remortgage can involve valuation, legal and arrangement fees that a personal loan typically doesn't carry — these should be added to the total cost comparison, not just weighed against the headline interest rate.
Term Length Can Offset a Lower Rate
Even a lower rate on secured borrowing can result in more total interest paid if repaid over a long mortgage term rather than a much shorter personal loan term — comparing total cost over the realistic repayment period, not just the rate, gives the true picture.
Loan Calculator
Calculate monthly loan repayments, total interest and cost of borrowing.
Open Loan calculatorGetting the Funding Decision Right
- Get like-for-like quotes for a further advance, remortgage and personal loan for the specific amount needed.
- Add in all arrangement fees, not just headline rates.
- Compare total cost over the realistic repayment period for each option.
- Confirm planning permission and building regulations requirements before finalising the amount to borrow.
- Match the funding route to the size of the project, rather than defaulting to one option for every extension.
Frequently asked questions
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