The short version
- Most mortgage offers last six months. Several lenders give nine months on new build.
- Many lenders will extend an offer, but usually with a fresh credit and affordability check, sometimes a new valuation, and sometimes a new rate. Some won't extend at all.
- The answer is timing: compare each buyer's offer expiry with the realistic handover date, and act months ahead, through the agent and the broker.
How long offers last
A standard mortgage offer usually lasts six months. Because new build so often runs late, several lenders now give longer on new build purchases:
| Lender | New build offer | Extensions |
|---|---|---|
| Nationwide | 9 months | None (15-day grace if the lender has the certificate of title in time) |
| Santander | 9 months on new build products | Considered, with a fresh credit and affordability check |
| Skipton | 9 months | 3 months, with up-to-date documents |
| Coventry | 9 months | Once, possibly with a new valuation |
| Virgin Money | 210 days | None on new applications |
| Barclays | 6 months | Once, for 6 months, after a full credit check |
| NatWest | 6 months | Up to two, of up to 3 months each |
| HSBC | 180 days | Once, 90 days for a home still being built |
From the lenders' own broker criteria pages and forms, checked 23 October 2026. Some count from the application, not the offer. Criteria change often, so the buyer's broker should check the actual offer.
What an extension involves
An extension isn't automatic. The broker asks the lender, often weeks before expiry: Barclays wants at least two weeks' notice, and Coventry a month. The lender then usually:
- runs a fresh credit search and checks affordability again;
- may ask for up-to-date proof of income;
- may order a new valuation, sometimes with a fee;
- may need a new product, at today's rate. Santander and Halifax need a new product, while NatWest and Skipton can keep the original.
A buyer whose circumstances have changed since the first offer, such as a new job, can find the extension harder than the original.
If the offer runs out
If an offer expires before completion and can't be extended, the buyer needs a new mortgage application: a new product, possibly a higher rate, and a new valuation. If the valuation has moved, the loan to value can change too. A buyer who can't get a new offer may be unable to complete, and could lose their deposit.
Before we built PlotBot, one sale's completion date slipped, but nobody told the buyer's broker. They found out with only weeks left on the mortgage offer, and had to rush an extension through.
With PlotBot, the developer updates the build date once and everyone on the plot sees it straight away, so the broker can be told the same day.
The paperwork lenders need at the end
Even with a valid offer, the lender won't release the money until it has what it needs. Have these ready before notice is served:
- The new home warranty cover note: NHBC says mortgage funds are generally not released until one has been issued
- The building control completion certificate
- Any final inspection the lender needs, booked in good time
- The UK Finance Disclosure of Incentives form: without it, Nationwide's valuer returns a nil valuation
The valuation has its own shelf life too. Santander's new build valuations last nine months from inspection, and Halifax's 12 months.
What developers and agents can do
- Note the buyer's lender and when their offer expires, alongside the expected handover date.
- Where handover is a long way off, the broker can look at lenders with longer new build offers.
- Check every buyer's offer expiry against the realistic handover date, not the brochure date, every month.
- Flag any offer that will run out within three months of handover, and tell the agent and the broker straight away.
- When handover moves, tell everyone the same day, so the broker can ask for an extension in good time.
- Don't serve notice on a buyer whose offer won't last to the completion date.
- Have the warranty, building control and disclosure paperwork ready, so the money isn't held up at the end.
Every mortgage offer watched against your handover dates.
PlotBot tracks each buyer's mortgage offer expiry against your handover dates, so a slipping build shows up as a risk months ahead, not at notice. When a handover date moves, everyone involved is told straight away. PlotBot never contacts your buyers: the chase goes to the agent and the broker.
Questions developers and agents ask
How long does a mortgage offer last on a new build?
Usually six months, but several lenders give nine months on new build, including Nationwide, Santander, Skipton and Coventry. The buyer's offer letter gives the exact date.
Can a mortgage offer be extended if the build is late?
Often, but not always. Many lenders extend once, usually after a fresh credit and affordability check and sometimes a new valuation. Some, such as Nationwide, don't extend new build offers at all. The buyer's broker asks the lender.
What happens if the offer expires before completion?
The buyer needs a new application, possibly at a different rate and with a new valuation. If they can't get a new offer, they may not be able to complete, which puts the sale at risk.
Sources
- Offer periods and extensions: Nationwide; Santander; Skipton; Coventry; Virgin Money; Barclays; NatWest; HSBC; Halifax
- Offers expiring during build delays: Santander (May 2025)
- Warranty cover notes: NHBC; lenders' warranty expectations: UK Finance warranty guidance (October 2025)
- The disclosure form: Nationwide new build criteria
- If an offer expires: HomeOwners Alliance, Buying off-plan
This guide is general information, not mortgage advice. The buyer's broker and lender decide what applies to each offer.
Also read: Notice to complete on a new build: what developers need to get right