New-Build Warranties: What They Cover & Why Lenders Insist

Every new build in the UK is sold with a structural warranty, and most buyers file it away without reading it. That's a mistake in both directions: the warranty covers less than most owners assume when something goes wrong — and it matters more than most buyers realise when they apply for the mortgage, because lenders treat the warranty as a condition of lending.

What a new-build warranty is

A new-build warranty (sometimes called a builders warranty or structural guarantee) is an insurance policy on the construction of the home, usually running for 10 years from completion. The builder buys it; the cover belongs to the home and passes to each owner.

The best-known scheme is NHBC Buildmark, which covers the majority of UK new builds. The other names you'll commonly see are Premier Guarantee, LABC Warranty, Checkmate, ICW and Build-Zone. The cover structure is broadly similar across schemes, but the details — claim limits, excesses, what counts as structural — differ, which is why it pays to read the specific policy.

Structurally, almost every scheme splits into two phases:

• Years 1-2 — the defects period.The builder is responsible for putting right faults in how the home was built: plumbing, heating, windows and doors, and similar. The warranty provider acts as a backstop and resolution service if the builder won't engage.
• Years 3-10 — structural cover only. Cover narrows to major structural elements: foundations, load-bearing walls, roofs, chimneys. Everyday defects are no longer covered.

Why lenders insist on one

Here is the part that surprises buyers: the warranty isn't optional as far as your mortgage is concerned. Most UK lenders will only lend on a new or nearly-new home if it carries a warranty from a provider they recognise.Each lender maintains a list of acceptable schemes; the major names are accepted almost everywhere, while newer or niche schemes appear on some lenders' lists and not others.

Some lenders will alternatively accept a Professional Consultant's Certificate (an architect or surveyor certifying they monitored construction) — common on small developments and self-builds — but fewer lenders take this route, so it narrows your choice.

The practical consequences:

• No acceptable warranty = unmortgageable at much of the market. This is one of the property-side issues that can sink an application regardless of your income — the same category of problem as unmortgageable properties generally.
• It bites on resales too.If you buy a home that's under 10 years old, your lender will expect the remaining warranty term to be in place. That's also worth remembering as a seller within the first decade.
• Which scheme the developer uses can change your lender pool. On a development using a smaller warranty provider, check early that your preferred lender accepts it — before paying a reservation fee.

What's covered — and what isn't

The gap between what owners expect and what warranties pay out on is widest here. Broadly:

• Covered:defects in the builder's work in years 1-2; major structural failures in years 3-10; usually some cover for contaminated land and building-regulation breaches the scheme signed off.
• Not covered: cosmetic snagging reported after the early period, general wear and tear, condensation and shrinkage cracks (normal as a new home dries out), gardens, fences and boundaries in most schemes, appliances, and damage from alterations you make.

Snagging — the long list of cosmetic defects most new builds have at handover — is its own discipline with its own deadlines, covered step by step in our new-build snagging guide. The short version: report everything early and in writing, while the builder is still on the hook.

Deposit protection if the builder fails

A less-known part of most schemes: if the builder becomes insolvent before completion, the warranty typically protects the deposit you've paid — commonly up to around 10% of the purchase price, subject to the scheme's caps. Given that exchange deposits on new builds are often paid many months before completion on off-plan purchases, this is genuine protection worth confirming (in writing) when you reserve.

After completion, the builder's failure doesn't remove your cover: years 3-10 claims are against the warranty provider, not the builder.

Making a claim: years 1-2 vs 3-10

Who you claim against depends on when the problem appears:

• Years 1-2: the claim goes to the builderfirst. Put defects in writing, keep copies, and set reasonable deadlines. If the builder stalls or disputes, escalate to the warranty provider's resolution service — that's exactly what it exists for.
• Years 3-10: the claim goes straight to the warranty provider, and it must be structural. Expect an assessment process, policy excesses, and a narrower definition of "structural" than most owners assume.

The step-by-step claims process — evidence to gather, time limits, escalation routes and what to do when a builder goes quiet — is documented in detail on our sister site's new-build warranty claims guide. If you're not sure what cover your home actually has, their warranty checker walks through identifying the scheme and the phase you're in.

The wider new-build mortgage picture

The warranty is one of several ways new builds are treated differently by lenders. The others that most often catch buyers out:

• Lower maximum LTVs — many lenders cap new-build lending below their standard range, with flats typically capped harder than houses, so the deposit you need can be bigger than for an equivalent second-hand home.
• Incentives are policed — developer deposit contributions and extras are disclosed to the lender and can affect what it will lend, covered in our new-build incentives guide.
• Offer expiry vs build delays — off-plan completions routinely outlive mortgage offers; see new-build delays and offer expiry.

Because those LTV caps and incentive rules differ lender by lender, the same buyer can face very different deposit requirements for the same plot depending on where they apply. Mortgage Affordability runs your details across 58 UK lenders at once so you can see which lenders' new-build rules fit your case. For the underlying criteria — which lender caps new-build flats at what LTV, and each lender's incentive limits — our sister site New-Build Mortgage Guide documents them lender by lender, with the dates they were verified.

Frequently asked questions

Do I need a warranty to get a mortgage on a new build?

In practice, yes. Most UK lenders will only lend on a new or nearly-new home if it carries a structural warranty from a provider they recognise — NHBC, Premier Guarantee, LABC and similar schemes — or, at some lenders, a Professional Consultant's Certificate instead. A new build with no acceptable warranty is unmortgageable at much of the market.

What does a builders warranty cover?

Typically two phases across 10 years. In roughly the first two years the builder is responsible for putting right defects in how the home was built — plumbing, heating, doors and windows and similar. From years three to ten, cover narrows to major structural problems such as foundations, load-bearing walls and roofs. Cosmetic snagging, wear and tear and routine maintenance are not covered.

Does painting or decorating a new build void the warranty?

No — normal decorating does not void a new-build warranty. What can affect cover is unauthorised structural alteration, or damage caused by work you have had done. Claims relate to defects in the original construction, so keeping records of any alterations helps if a dispute arises.

What happens if the builder goes bust?

The warranty survives the builder. If the builder fails before completion, most schemes protect your deposit — commonly up to around 10% of the purchase price, subject to the scheme's caps. After completion, structural claims in years three to ten are made against the warranty provider, not the builder, so a failed builder does not remove your cover.

Does the warranty transfer if I buy a nearly-new home?

Yes — new-build warranties attach to the property, not the first owner, so the remaining term transfers to you on resale. Lenders will check the remaining cover when you apply: a five-year-old home with five years of structural cover left is generally straightforward, while homes under 10 years old with no surviving warranty can face extra scrutiny.

Last updated: August 2026