Buying at auction: bridging and mortgage options

Auction purchases require completion in 28 days, far less time than most mortgage lenders need. Bridging finance solves the deadline problem — but it has costs, regulation rules, and an exit strategy you need to plan before you bid.

Last checked 13 September 2026. Editor: Kris · editorial standards

Six sections. Each anchored to a first-party source, checked 13 September 2026.

1. The 28-day problem

When the auctioneer's hammer falls, you are legally committed to completing the purchase, normally within 28 days. A standard residential mortgage application takes 4–8 weeks from application to offer and then requires a valuation and legal work on top. In most cases, a standard mortgage cannot legally complete within an auction's timeframe, and failing to complete means losing your 10% deposit and potentially being sued by the vendor for additional losses.

2. What bridging finance is

A bridging loan is a short-term secured loan, typically 1–18 months, designed to fill a gap between a property purchase and longer-term financing. Lenders can often issue a bridging loan in 3–10 working days, making them suitable for auction completions. The loan is secured against the property being purchased, or against other property you own. Interest is usually charged monthly and rolled up into the balance (not paid monthly), so the total owed grows throughout the loan term.

3. Regulated versus unregulated bridging

Bridging loans are either regulated or unregulated. A bridging loan is regulated if the security property is a dwelling and the borrower or a close family member currently lives there or intends to live there. In all other cases (buy-to-let, investment, or refurbishment before sale), the loan is unregulated. Regulated bridging gives you FCA protections and access to the Financial Ombudsman; unregulated bridging does not. For an auction purchase of a property you intend to live in, ask explicitly whether the bridging loan you are being offered is regulated (FCA Handbook MCOB 1.2).

4. What bridging costs

Bridging loans are materially more expensive than standard mortgages. Typical costs include: a monthly interest rate of 0.5–1.2% (equivalent to 6–14% per annum); an arrangement fee of 1–2% of the loan; a valuation fee; and exit fees on some products. On a £200,000 bridging loan at 0.75% monthly interest for four months, the interest cost alone is £6,000 before fees. The longer you take to exit, the higher the total cost. This makes the exit strategy the most important part of the plan.

5. The exit strategy

The exit from a bridging loan is typically one of three things: a standard residential mortgage (once the property is habitable and the applicant's circumstances permit), a buy-to-let mortgage, or a sale of the property. Define your exit before you take the bridging loan, not after. If the property needs renovation before a mainstream lender will value it acceptably, factor in the build time and contingency. Lenders will ask for the planned exit at application; a vague answer will affect the interest rate offered.

6. Pre-arranged mortgages for auction

For properties in good condition that a standard mortgage lender would value normally, it is possible to get a mortgage offer in place before the auction, which removes the need for bridging. This requires a cooperative lender, a property listed before the auction day, a valuation instruction in advance, and solicitors ready to exchange on the day. Not every lender supports this. Ask a broker whether the specific property would suit a pre-arranged mortgage or requires bridging. If using bridging, instruct both the bridging lender and the exit-mortgage broker at the same time to minimise the bridging period.

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General information, not advice. Mortgage Brokers List is a directory and a set of free tools. Only an FCA-authorised adviser can recommend a mortgage for your circumstances. See our editorial standards.