New Build Mortgage FAQ
General information only. This is not financial advice.
Last reviewed: 2026-06-06
How long does a mortgage offer last on a new build?
Most mortgage offers are valid for 6 months. For new builds, many lenders extend validity to 9 or 12 months to accommodate longer build timescales and delayed completion dates. This extended period is important because new build completions frequently overrun. If your build is not complete before the offer expires, you will need to request an extension or reapply — and a new affordability assessment will apply at that point, potentially at a different interest rate. Always confirm offer validity with your broker before exchanging contracts.
Do developer incentives affect my mortgage?
Yes. Lenders require full disclosure of all developer incentives, including deposit contributions, stamp duty payments, cashback, and free upgrades. Most lenders cap acceptable incentives at 5% of the purchase price. Incentives above this threshold are deducted from the lender's valuation before the LTV is calculated, which may reduce the amount you can borrow. Failure to disclose incentives when applying constitutes mortgage fraud. Your broker and solicitor both have duties to report material incentives to the lender.
Why might a new build property value below the purchase price?
New build properties often carry a premium over comparable second-hand properties, reflecting the developer's profit margin and the marketing of the show home. When a lender's surveyor values the property independently — based on actual comparable sales — they may conclude the property is worth less than the agreed purchase price. This is called a down-valuation. It does not mean you cannot proceed, but it reduces the lender's assessed LTV and may require you to increase your deposit to cover the shortfall between the surveyor's valuation and the purchase price.
What happens between exchange and completion on a new build?
On a new build purchase, you exchange contracts while the property is under construction (committing to buy at the agreed price) and complete once it is finished and ready. The period between exchange and completion can range from a few weeks to over a year. Your mortgage offer must remain valid until completion. Unlike a standard resale purchase, there is no fixed completion date at exchange — the developer notifies you when the property is ready. New build reservations also typically require a reservation deposit (usually £500–£2,000), which is separate from the exchange deposit.
Should I get a snagging survey on a new build property?
Yes. A snagging survey is an independent inspection to identify defects, unfinished work, or items that fall below the developer's specification or building regulations. Common issues include cosmetic defects, gaps in skirting, poorly fitting doors and windows, and plumbing problems. The survey is ideally carried out before legal completion so the developer can fix items before you move in. Developers are contractually obliged to rectify genuine snags. The NHBC Buildmark warranty (or equivalent) also provides protection for major structural defects for the first 10 years. A snagging survey is not part of the mortgage process but is a worthwhile buyer's protection.
Are any Help to Buy or government schemes available for new builds in 2026?
The original Help to Buy: Equity Loan scheme in England closed to new applications in 2023. In 2026, options for new build buyers include First Homes (a 30%+ discount on selected new build sites, for first-time buyers and key workers) and Shared Ownership (buying a share of a new build and paying rent on the rest). Availability depends on the specific development and developer. Wales has its own separate equity loan programme. Your broker can confirm which schemes apply to the property you are buying and which lenders accept those schemes.
Risk warning
Your home may be repossessed if you do not keep up repayments on your mortgage. New build property values can go down as well as up.
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