Will your mortgage offer outlast your build?
Mortgage offers expire — and new-build completion dates slip. Enter your expected months to completion and see, lender by lender, whether the offer (plus any extension) would still be valid, based on published policy verified 2026-07-13.
This is an information tool, not advice: it doesn't give a recommendation, a decision in principle, or a guarantee any lender will extend or honour an offer.
Worked example: build completes in 9 months
A fairly typical new-build timeline — 9 months from mortgage offer to expected completion.
12 of 17 lenders' offers would still be valid at 9 months — but 6 of those only because you request an extension first. Nationwide, Santander, Skipton, Coventry BS, Newcastle BS, Darlington BS cover 9 months on their initial offer with no extension needed; HSBConly reaches 9 months by using the one extension it allows — it's already at its ceiling.
Change the inputs below to model your own numbers.
A slower build: completes in 11 months
A build that's running later than planned — 11 months from offer to expected completion.
At 11 months, no lender we track covers you on its initial offer alone — 9 of 17 are still covered, and every one of them needs an extension request. NatWest is covered this way (covered with extension), but Virgin Money is at risk — it removed its new-build extension mechanism entirely on 30 Jan 2026, so a build running this late would need a brand-new application.
Change the inputs below to model your own numbers.
Between 1 and 24 months.
At 9 months to completion, 12 of 17 lenders' offers would still be valid (6 only via an extension).
Covered by the initial offer
No extension needed — the standard new-build validity already reaches this far.
- Nationwide9mo initial
No new-build extension available.
No extension on the 9-month offer — a 15-day grace period only, subject to the Certificate of Title being received before expiry.
9 months (270 days) for offers issued on/after 26 Jun 2025 — the cleanest and best-documented figure on this panel. Legacy offers issued before that date keep the old 6 months + up to 45-day extension (inclusive of the 15-day grace).
- Santander9mo initial → up to 12mo
Extension: 3mo at a time, up to 12mo total.
A further ~3-month extension where the build won't complete within 9 months (max ~12 months total). The broker uploads a request via MATS with the expected completion date, an updated product if the original has expired, and current proof of income.
9 months, raised from 6 months effective 6 May 2025. The extension triggers a re-score and a new credit search, and may require further documentation or a revaluation (not stated as free).
- Skipton9mo initial → up to 12mo
Extension: 3mo at a time, up to 12mo total.
A further 3-month extension beyond the initial 9 months, subject to an up-to-date credit search and affordability assessment (i.e. a re-underwrite). The build must complete within 12 months of the original offer date overall, or the offer lapses and a fresh application is required.
9 months is standard for all Skipton new-build, with a hard 12-month ceiling overall.
- Coventry BS9mo initial → up to 12mo
Extension: 3mo at a time, up to 12mo total.
A further 60 working days (~3 months) via the New Build offer extension form. Apply up to 30 days before the original offer expires.
9 months from date of application — this supersedes the 2022 industry-aggregator figure of 6 months; the current primary page wins. Re-underwrite/re-valuation mechanics for the extension aren't explicitly published.
- Newcastle BS9mo initial
No new-build extension available.
No published general extension policy — no standard 'N extra days' rule was found. One Financial Ombudsman decision shows a case-by-case discretionary extension, but that isn't a standing policy.
9 months was explicitly retained as a separate, longer new-build period when the general 3-to-6-month extension was announced (May 2023). What happens beyond 9 months is a genuine gap — confirm with Newcastle.
Partially verified — confirm with the lender before relying on this.
- Darlington BS9mo initial → up to 12mo
Extension: 3mo at a time, up to 12mo total.
The Society will agree extensions of up to 3 months. Extensions of 14 days can be agreed without re-underwriting, implying anything beyond 14 days triggers a re-underwrite (exact mechanics not spelled out).
9 months verified via the Darlington Lending Manual v3.27 (7 Jul 2025), corroborated by the L&G aggregator table.
Covered, but only with an extension
The initial offer would expire first — you'd need to request the extension below.
- NatWest6mo initial → up to 12mo
Extension: 3mo at a time, up to 12mo total (free revaluation on extension).
Two further extensions of up to 3 months each (6+3+3). The 1st must be requested within 30 days of the 6-month offer expiring; the 2nd, 30 days before the 1st extension expires. The broker completes an offer-extension template plus a no-material-change declaration; the original product is kept, or you can switch to the current range.
Each extension requires a successful credit search (no new footprint on your file) and a free refreshed property valuation. Policy in place since 9 Mar 2018.
- Barclays6mo initial → up to 12mo
Extension: 6mo at a time, up to 12mo total (original valuation kept on extension).
One extension only, of +6 months, via the New Build Mortgage Offer Extension Declaration form. Requires confirmation that circumstances are unchanged plus a new credit search, and must be requested at least 2 weeks before offer expiry. A second extension isn't permitted — a fresh application is needed instead.
The original valuation is kept for new-build (not re-run) unless a significant change triggers a full underwriting reassessment. Barclays' intermediary site blocks automated access — this is sourced from our 2026-06-24 internal criteria scrape, corroborated by broker guides and Barclays' own extension-form PDF.
- HSBC6mo initial → up to 9mo
Extension: 3mo at a time, up to 9mo total.
One extension only, requestable in the last 30 days of the offer, provided there's no change to the application or your circumstances. It keeps the existing product rate and is requested via an Application Amendment Form.
Extendable to 270 days (9 months) total — a larger extension window for new-build than the +30 days offered on non-new-build (introduced Mar 2024). No documents are required if nothing has changed; if your circumstances or application have changed, the case must be resubmitted for full review.
- Accord6mo initial → up to 12mo
Extension: 6mo at a time, up to 12mo total.
The broker calls the underwriter handling the original offer 30 days before expiry for re-issue requirements. Accord's generic (non-new-build) copy says offers 'cannot be extended after 6 months' — the new-build-specific hub carves out this penalty-free re-issue instead.
Framed as a penalty-free 6-month re-issue rather than a formal 'extension' — net ceiling around 12 months. Re-issue requirements are set by the underwriter and aren't fully published, and the generic-vs-new-build wording conflicts slightly.
Partially verified — confirm with the lender before relying on this.
- TSB6mo initial → up to 12mo
Extension: 6mo at a time, up to 12mo total.
New-build qualifies for a 28-day extension followed by a further 180 days, or a 180-day extension followed by 28 days. Request via the 'Application for offer extension - New Build only' form within 14 days of the original expiry.
The 180-day extension leg triggers a full re-underwrite: revaluation, fresh credit search, affordability reassessment. Standard (non-new-build) purchases get only one ~28-day extension.
- Principality8mo initial → up to 16mo
Extension: 8mo at a time, up to 16mo total.
Framed as '8 months initial + 8-month extension' (a max theoretical window of ~16 months if the build is delayed). Exact trigger conditions, whether a re-underwrite or revaluation is required, and any fee are not stated on the public page.
240 days (8 months) is verified and supersedes the 2022 aggregator's '7 months + 1 month' figure. Extension mechanics are unpublished — confirm before relying on the full 16-month window.
Partially verified — confirm with the lender before relying on this.
At risk of expiring
Even with any published extension, this completion timeframe would outlast the offer.
- Virgin Money7mo initial
No new-build extension available.
Extension REMOVED as of 30 Jan 2026: "From Friday 30 January 2026 we will no longer accept offer extension requests on new-build applications." Cases past 210 days now need a brand-new application (new product and new valuation) — the same as a standard purchase.
210 days (~7 months) for new-build, unchanged. Before 30 Jan 2026 a further 210-day extension with re-assessment and a valuer referral was available — that policy no longer applies. Don't rely on older broker articles that still describe it.
Confirm with the lender
No single published new-build figure exists for these lenders — don't assume a number.
No single published figure — confirm with the lender.
No formal extension mechanism — a broker can re-select a new-build product with a later completion deadline. Not automatic, and the rate is re-quoted at the prevailing rate (the original rate isn't guaranteed).
Halifax publishes no single new-build offer-validity figure — it attaches a completion deadline to each product instead. Brokers report effective windows of roughly 9-15 months depending on the product, but that is not a fixed policy number. Confirm the current product's completion deadline with Halifax.
Not published — confirm with the lender before relying on this.
No single published figure — confirm with the lender.
Not published. Perenna's FAQ says only to contact the Mortgage Process Team to discuss your options if completion won't happen before expiry.
No distinct new-build validity figure is published (the standard purchase offer is 150 days, ~5 months). Perenna also won't issue an offer against a plot number/site address — a final property address is required first. Confirm directly with Perenna.
Not published — confirm with the lender before relying on this.
No single published figure — confirm with the lender.
For new-build build delays, intermediaries apply (via the New Build Offer Extension form) to extend once for a further 6 months. Request only in the month before expiry — it can be extended once only, and any further overrun needs a new application.
Leeds doesn't publish a separate new-build initial-validity figure distinct from its standard 6 months, so the starting point for a new-build case is unconfirmed — treat it as a gap rather than assuming the standard figure applies. The one-time +6-month extension itself is confirmed on Leeds' own page; additional documents (payslip/bank statement) may be required even with no change, implying a partial re-underwrite.
Partially verified — confirm with the lender before relying on this.
No single published figure — confirm with the lender.
Not published anywhere found — no extension length, trigger or fee is disclosed.
Furness's current criteria page states no offer-validity figure at all for new-build. The only dated confirmation is a 2017 announcement of a 6-month standard offer (raised from 3), which the 2022 L&G aggregator corroborates as unchanged for new-build — but that's not a firm, current new-build-specific figure. Confirm with Furness.
Not published — confirm with the lender before relying on this.
Get the full breakdown by email
We'll send the complete lender-by-lender offer-validity breakdown and keep you posted as policies change.
Indicative only, based on published lender policy verified 2026-07-13. This isn't a guarantee any offer will or won't be honoured — always confirm extension mechanics and deadlines directly with your lender. Information, not advice.
FAQ
What happens if my offer expires before completion?
If an extension isn't available, or you've already used it, you'll need a fresh application: a new product (at the then-current rate, not your original one), a new credit search, and usually a revaluation. Ask your broker to flag this risk early — extensions almost always need to be requested before the original offer lapses, not after.
Does requesting an extension affect my credit file?
Most lenders run a fresh credit search as part of an extension request, but it's typically a soft or lender-only search that doesn't leave the kind of footprint a new application does — confirm the specific mechanics with your lender before you apply elsewhere.
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