NHBC Buildmark warranty explained — what's covered and how to claim

The NHBC Buildmark warranty is a 10-year warranty that comes with most newly built homes in the UK, covering the builder’s obligations in years one and two, and NHBC’s own structural guarantee from year three to year ten. Understanding precisely what each period covers — and what it excludes — is essential before you try to make a claim.

This guide explains the Buildmark warranty structure in plain terms, defines what counts as a structural defect under NHBC’s rules, explains how to claim in each period, and sets out what the warranty does not cover.

What is the NHBC Buildmark warranty?

NHBC (National House-Building Council) is the UK’s largest new home warranty provider and building standards organisation. The Buildmark warranty is registered in your name at the point your new home is built and transfers automatically if you sell the property within the ten-year period.

The warranty is not an insurance policy in the traditional sense — it is a warranty contract between you, your builder, and NHBC, with different obligations applying to each party depending on how long it has been since your home was legally completed.

Before completion, NHBC also inspects homes during construction to confirm they meet NHBC technical standards. Passing these inspections does not mean your home is defect-free — they are spot checks at key stages, not a comprehensive quality audit.

The three periods of NHBC Buildmark cover

Year 1: builder responsible for all defects

During the first year after legal completion, your builder is responsible for rectifying all defects arising from their failure to build to the NHBC Technical Standards. This is the broadest period of cover and includes:

• Cosmetic defects (paint finish, tiling, joinery)
• Fixture and fitting failures
• Plumbing and drainage issues
• Window and door operation problems
• Any item that deviates from the agreed specification

The NHBC uses the term “defect” to mean an item that does not meet the NHBC Technical Standards — the detailed technical requirements your builder agreed to follow. A defect is not the same as fair wear and tear, which is explicitly excluded.

How to claim in year 1: Contact your builder’s after-sales or customer care team in writing, with photographs and a clear description of each defect. The Consumer Code for Home Builders (which applies to developers registered with NHBC) requires your builder to have a formal after-sales process and to respond within a reasonable timeframe. If your builder does not respond or disputes your claim, escalate to the NHBC Resolution Service — a free mediation and adjudication service available during years one and two.

Year 2: builder responsible for fixtures, fittings, and service systems

During the second year, your builder’s direct responsibility narrows. They remain responsible for defects in:

• Fixtures and fittings — kitchen cabinets, bathroom fittings, doors, windows, wardrobes
• Service systems — heating system (boiler and radiators), plumbing, drainage, electrical systems, ventilation

Purely cosmetic issues that arise in year two — a small paint scuff that appears after you have been living in the property, for example — are generally not covered in year two unless they were documented as a defect during year one.

How to claim in year 2: The process is the same as year one — contact your builder in writing. If the builder disputes responsibility or fails to act, the NHBC Resolution Service is available throughout years one and two. Decisions made through the Resolution Service are binding on your builder.

Years 3–10: NHBC covers structural defects only

From year three onwards, your builder’s direct warranty obligation ends. NHBC itself steps in — but only for structural defects. This is where many homeowners are caught out. NHBC’s year 3–10 cover does not include:

• Cosmetic issues
• Fixture and fitting failures
• Boiler or heating system breakdowns
• General maintenance items

NHBC’s structural cover in this period is what most people think of when they hear “10-year warranty,” but it is considerably narrower than the full cover available in years one and two.

How to claim in years 3–10: Contact NHBC directly (not your builder) via their claims line or online portal. NHBC will investigate, appoint an inspector, and determine whether the defect meets their definition of a structural defect.

What counts as a structural defect under NHBC?

NHBC defines a structural defect as physical damage to the home caused by a failure to meet the NHBC Technical Standards that affects, or will affect, the structural stability of the home, or that makes the home uninhabitable or puts its occupants at risk.

Common examples of claims accepted under structural cover include:

• Subsidence or heave causing significant cracking to load-bearing walls or foundations
• Roof structure failure
• Defective waterproofing leading to significant water ingress affecting structural elements
• Serious defects in load-bearing components

Common examples of issues NHBC does not consider structural include:

• Hairline cracking in plasterwork (normal movement and settlement)
• Poorly fitted kitchen units
• Boiler breakdown
• Damp caused by lack of maintenance (as opposed to construction defect)
• Roof tile slippage without structural implication

NHBC publishes a document called the Buildmark: what’s covered guide, which is the definitive reference for what falls within each period of cover. This document is provided at completion and is also available on the NHBC website.

What NHBC Buildmark does not cover

The following exclusions apply across all three periods:

• Fair wear and tear — gradual deterioration from normal use is not a defect
• Cosmetic issues arising after year 2 — paint fading, surface scratches, grout discolouration
• Owner modifications — any defects caused by alterations you have made to the property
• Condensation and mould caused by insufficient ventilation — unless the root cause is a construction defect
• Subsidence caused by trees — unless the ground investigation standards were not followed
• Damage caused by extreme weather events — these are typically covered under your home buildings insurance, not your NHBC warranty
• Items not built to NHBC Technical Standards where NHBC did not register the home

It is worth noting that NHBC cover also excludes defects in gardens, boundary walls, and external fencing unless these are specified as included in your warranty schedule.

The NHBC Resolution Service

If your builder disputes your claim in years one or two, or simply does not respond within a reasonable period, the NHBC Resolution Service offers a free route to resolution. The process involves:

1. Submitting your complaint to NHBC with supporting evidence (photographs, written communications with your builder, your snagging list)
2. An NHBC Resolution Surveyor inspects the property
3. NHBC issues a decision identifying which items are defects under the Technical Standards
4. The builder is required to carry out the work identified in the decision

Decisions are binding on the registered builder but not on you — if you disagree with the outcome, you can seek a further independent review.

Escalation beyond NHBC

If you remain dissatisfied with the NHBC Resolution Service outcome, your options are:

• Financial Ombudsman Service (FOS): NHBC is an authorised insurer for part of its warranty product. If your complaint relates to the insurance elements of the Buildmark (primarily the year 3–10 structural period), you can escalate to the FOS free of charge.
• New Homes Ombudsman Service (NHOS): If your dispute relates to your developer’s conduct — including failure to follow the Consumer Code for Home Builders — rather than the warranty specifically, the NHOS is the appropriate route.
• Court: For disputes where NHBC’s position is that a defect does not meet its definition, the county court or small claims court remains an option. An independent expert report from a RICS-registered surveyor will significantly strengthen your case.

Australian equivalent

For Australian readers, the equivalent of the NHBC Buildmark is the state-based statutory warranty system, which varies by state. In New South Wales, the Home Building Act 1989 provides a six-year warranty for major defects and a two-year warranty for non-major defects. In Queensland, the Queensland Building and Construction Commission Act 1991 (administered by QBCC) provides a six-year, six-month warranty for structural defects and one year for non-structural defects. In Victoria, the Domestic Building Contracts Act 1995 provides a ten-year warranty for major defects and two years for non-major defects.

Unlike the UK’s NHBC model — where a single national body administers the warranty — Australian statutory warranties are enforced through state licensing bodies and tribunals (NCAT in NSW, QCAT in QLD, VCAT in VIC).

Key takeaways

• The NHBC Buildmark warranty runs for 10 years but coverage narrows significantly after year two — year 3–10 cover is for structural defects only, not fixtures, fittings, or cosmetic issues
• In years one and two, your builder is directly responsible for defects and must follow the Consumer Code for Home Builders in dealing with complaints
• If your builder disputes a claim in years one or two, the NHBC Resolution Service provides a free, binding adjudication process
• “Structural defect” under NHBC has a specific definition — it does not include normal settlement cracking, cosmetic wear, or maintenance items
• Fair wear and tear, owner modifications, and defects arising after year two that are not structural are explicitly excluded from all Buildmark cover
• Unresolved disputes about the warranty’s insurance elements can be escalated to the Financial Ombudsman Service; disputes about developer conduct go to the New Homes Ombudsman Service