New build mortgages

Buying a new build property involves mortgage rules that differ from a second-hand purchase. The valuation gap, tight exchange deadlines and builder incentive restrictions catch buyers out — this guide explains what to check.

Last checked 13 September 2026.

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

1. Why lenders treat new builds differently

A new build property is often priced at a premium to the surrounding resale market. When a lender values it independently, the valuation can come in below the purchase price, especially on high-rise flats in large developments. If the valuation is lower than the purchase price, the lender calculates the loan-to-value on the valuation, not the purchase price, which means you need a larger cash deposit to bridge the gap or you need to renegotiate with the developer. Many lenders apply a lower maximum loan-to-value on new builds for this reason: commonly 85% LTV for houses and 75% for flats, compared to 95% available on standard residential purchases. Use the LTV calculator to check where you stand.

2. The exchange deadline

Developers set a deadline by which contracts must be exchanged, typically within 28 days of reservation. A mortgage application takes time: the lender needs to complete an affordability assessment and instruct a valuation. If the mortgage offer arrives after the exchange deadline, the developer may keep your reservation fee and resell the plot. Instruct a broker and solicitor on the day you reserve; do not wait to see the developer's recommended mortgage adviser before speaking to an independent broker.

3. Developer incentives and cashback

Developers sometimes offer incentives to buyers: upgrades, paid legal fees, or cashback. Lenders require that all incentives above a threshold are declared and may deduct their value from the purchase price when calculating the loan-to-value. A £5,000 “cashback on completion” that the lender is not told about is a material omission on the mortgage application. Declare all incentives to your broker and solicitor; they are required to disclose them to the lender regardless.

4. Structural warranties

Almost all new build mortgage lenders require a ten-year structural warranty from an approved provider. The most common is NHBC Buildmark, but warranties from Premier Guarantee, LABC Warranty and others are also accepted by most lenders. The developer should provide the warranty as part of the purchase; confirm this is in place before exchange. Without a warranty, most lenders will not lend. NHBC Buildmark covers defects in materials and workmanship for ten years from the build date.

5. The developer's recommended broker

Many developers have a preferred or in-house financial services arm that they encourage buyers to use, sometimes making the reservation conditional on a free financial consultation. That consultation is not an obligation to proceed with their broker. The developer's broker may be whole-of-market or may not; the referral arrangement means the developer or its partner receives a commercial benefit when you use them. Ask whether they cover the whole market; check the firm on the FCA Register; and compare what they offer against an independent broker. See the estate agent's recommended broker guide for the disclosure rules that apply.

6. Help to Buy: Equity Loan (legacy)

The Help to Buy Equity Loan scheme in England closed to new applicants in October 2022 and the final completions took place in March 2023. If you have an existing Help to Buy equity loan, the rules on repayment and staircasing continue to apply for the life of the loan. GOV.UK has current guidance on managing a Help to Buy loan: GOV.UK — Help to Buy: Equity Loan.

Brokers whose website mentions first-time buyer mortgages

886 firms in our directory mention first-time buyer mortgages on their own website. That's what they say about themselves, not an assessment by us, so check that a firm handles your situation and look it up on the FCA Register before taking advice.

More guides

• How to choose a mortgage broker
• Mortgage declined
• Cifas markers and mortgages
• Mortgages with bad credit
• Mortgages for the self-employed
• First-time buyer mortgages
• Buy-to-let mortgages
• Remortgage guide
• Contractor mortgages
• Agreement in Principle
• Credit score and mortgages
• Mortgage broker fees
• Divorce and mortgages
• Gifted deposit
• Should you use the estate agent's recommended broker?
• Documents for a mortgage application
• What happens at a mortgage fact-find

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.