NHBC confirms that during the first two years after legal completion of a new-build home, the builder, not NHBC, is responsible for fixing problems arising from a failure to meet NHBC’s own building requirements, with NHBC stepping in only once the builder’s own complaints process has been exhausted.

The two-year builder period

NHBC’s own guidance is direct about where responsibility sits immediately after completion: during the first two years, the builder is responsible for rectifying problems arising from the builder’s failure to meet NHBC’s requirements, not NHBC itself. A boiler that develops a fault in this window, whether that is a workmanship issue with the original installation or a component failure, is first and foremost a matter for the developer’s own aftercare or customer service team, in the same way any other defect in this period is.

How to report a fault

NHBC says a homeowner should contact the builder as soon as reasonably possible, and always within the builder warranty period itself, keeping a record of that contact. This record matters beyond simply getting the fault fixed: it becomes the evidence needed later if the builder does not resolve the problem and the homeowner needs to escalate to NHBC’s resolution service.

When NHBC steps in

NHBC describes its role as guaranteeing the builder’s obligations under the builder warranty, meaning it steps in if the builder fails to comply. Before that happens, NHBC sets out steps a homeowner needs to have completed: notifying the builder within the warranty period, allowing the builder reasonable time to carry out repairs, going through the builder’s full complaints process, and receiving the builder’s final written response. Only once these steps are done does NHBC’s resolution service become the next avenue, rather than being available as a first port of call for any boiler complaint.

Years three to ten

After the two-year builder warranty period ends, Buildmark moves into an eight-year insurance period covering physical damage to the home caused by a failure to build to NHBC’s requirements, generally concentrated on structural elements such as foundations, load-bearing elements and the weatherproofing of the external envelope. A boiler fault arising well into this later period sits in a different part of the warranty structure than one arising in the first two years, and is less likely to be the kind of defect this later insurance period is designed to address, since it is framed around structural rather than mechanical or appliance-level failures.

Does Buildmark name boilers specifically?

NHBC’s published guidance on the first two years describes the general process for defects without itemising specific building components such as boilers by name. This means a boiler fault is treated under the same general builder-warranty process as any other defect covered by the builder’s obligations, rather than being singled out for separate treatment, and the specific policy booklet and certificate issued for a particular home is the reference for what is and is not included for that property.

Other warranty providers

NHBC is one of several structural warranty providers used across new-build housing in the UK, and a home built under a different provider’s warranty follows that provider’s own equivalent process rather than NHBC’s. Checking which warranty applies to a specific new-build property, usually confirmed at the point of purchase, is the first step before assuming NHBC’s process described here applies.

What to keep alongside the warranty

Separately from the Buildmark warranty itself, a new-build boiler should still have been commissioned and recorded in the way any other boiler installation is, including the manufacturer’s own guarantee and the completed commissioning paperwork covered elsewhere on this site. Keeping this documentation alongside the Buildmark policy booklet matters because a homeowner disputing a boiler fault with the builder may need to show what was actually installed and when it was commissioned, not just that a defect has appeared, particularly where the builder disputes whether a fault falls within its warranty obligations at all.

Why the timing of a fault matters

Because the Buildmark structure changes so significantly between the second and third year of ownership, exactly when a boiler fault first appears, and when it was first reported, can affect which part of the warranty framework is relevant and which party, the builder directly or NHBC’s resolution service, is the appropriate first point of contact. A homeowner who notices an intermittent fault close to the two-year mark has a practical reason to report it promptly rather than wait, since reporting within the builder warranty period is what NHBC’s guidance requires before its resolution service becomes available at all.

FAQs

Who deals with a faulty boiler in a new-build home during the first two years?

NHBC says the builder is responsible for rectifying defects in this period, not NHBC directly.

When can a homeowner ask NHBC to step in?

Only after notifying the builder within the warranty period, allowing reasonable time for repair, completing the builder’s complaints process and receiving its final response.

Does the eight-year insurance period from year three cover a boiler breakdown?

It is focused on structural defects such as foundations and weatherproofing rather than mechanical appliance failures, so a general boiler breakdown in this period is less likely to be the kind of issue it is designed to cover.

Does every new-build home have an NHBC warranty?

No. Other structural warranty providers are also used, and each has its own equivalent process.

Bottom line

NHBC’s Buildmark warranty puts the builder, not NHBC, in charge of fixing a faulty boiler during the first two years after a new-build home is completed, with NHBC’s resolution service acting as a backstop only once the builder’s own complaints process has been exhausted. The later, structural insurance period is framed around defects like foundations and weatherproofing rather than boiler faults specifically. This is general information, not advice on a specific policy; the individual Buildmark policy booklet and certificate confirm what applies to a particular home.

Sources

This guide draws on the following primary sources, current as of 22 September 2026:

• NHBC, “In the first two years of the policy”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.