No, windows and doors are not covered by the NHBC Buildmark warranty as standard structural defects cover, but they are covered for up to two years under the warranty’s ‘non-structural’ provisions (NHBC, 2026). This means that if your windows or doors fail due to poor installation or faulty materials within the first two years, you can make a claim. However, after that period, you must rely on the individual product manufacturer’s guarantee, which typically lasts 10 years.
The key variable is the type of failure. The NHBC covers windows and doors only for ‘non-structural’ defects, such as draughts, sticking mechanisms, or condensation between panes, that appear within two years of the home’s completion. Structural issues, like a wall collapsing, are covered for up to 10 years, but windows and doors are not considered structural components. This applies to all new-build homes registered with NHBC in England, Wales, and Northern Ireland. If your home was built before 2010, different terms may apply under the older NHBC scheme.
Two-year cover for installation and materials
Under the NHBC Buildmark policy, windows and doors are covered for defects caused by poor workmanship or faulty materials for the first two years after the home is completed. This includes issues like warped frames, broken seals causing condensation between glass panes, or doors that do not close properly. The NHBC states that you must report any such defect within the two-year period to your builder first, and if unresolved, to NHBC directly (NHBC, 2026). After two years, this cover ends permanently.
Manufacturer guarantees fill the gap
After the NHBC’s two-year cover expires, your windows and doors are protected by the manufacturer’s own guarantee, which typically lasts 10 years. This covers manufacturing defects like sealed unit failure (condensation between panes) or hardware faults. The Fenestration Self-Assessment Scheme (FENSA) requires all new windows and doors in England and Wales to be installed by a registered company, which must offer a guarantee that meets Building Regulations standards (FENSA, 2026). Always check your paperwork for the exact guarantee length and terms.
What is not covered by NHBC for windows and doors
The NHBC explicitly excludes ‘fair wear and tear’ and damage caused by neglect or misuse from its cover. This means that if your window hinges wear out after five years due to normal use, the NHBC will not pay for repairs. Similarly, accidental breakage of glass or damage from extreme weather is not covered. The NHBC also excludes cosmetic issues like minor scratches or paint defects, unless they affect the function of the window or door (NHBC, 2026). For these issues, your home insurance or the manufacturer’s guarantee is the appropriate route.
A worked example
A homeowner in a 2022-built three-bedroom semi-detached house in Milton Keynes notices condensation forming inside the double-glazed unit of their living room window two years after moving in. Under the NHBC Buildmark warranty, this counts as a non-structural defect, faulty sealed unit, and they must report it to the housebuilder before the two-year anniversary of the home’s completion date. The homeowner submits a claim six weeks before the deadline, and the builder replaces the entire window unit at no cost, saving an estimated £450 for a standard 1.2m² casement window. If they had missed the two-year window, they would have needed to claim under the window manufacturer’s 10-year guarantee, which often requires proof of purchase and may involve a call-out fee of £80 to £120. The Energy Saving Trust confirms that poorly sealed windows can increase heating costs by up to 20%, so prompt action under NHBC cover is both a financial and comfort priority.
| Item | Figure |
|---|---|
| Upfront cost after grants | £0 (covered by NHBC) |
| Yearly savings | £180 (reduced heat loss) |
| Payback period | Immediate |
| 25-year lifetime savings | £4,500 |
What homeowners often get wrong
The most common mistake is believing NHBC covers windows and doors for the full 10-year structural period. Here are three errors that cost homeowners time and money.
- Assuming 10-year cover for all window issues Many homeowners think any window defect is covered for a decade. In reality, only non-structural problems like sticking hinges or failed seals are covered for two years, after that, you lose NHBC protection and must rely on the manufacturer’s warranty, which may have exclusions for installation faults.
- Delaying the defect report until the last minute Homeowners often wait until the two-year anniversary to report issues. The NHBC requires you to notify the builder before the two-year deadline, if you report on day 731, the claim is void, and you could face a £1,200 bill for a full window replacement out of pocket.
- Confusing condensation types Many homeowners claim for condensation between panes, which is covered, but they also claim for external or internal condensation, which is not an NHBC defect. This wastes time and may lead to a rejected claim, leaving you to pay for dehumidifiers or ventilation upgrades costing £200 to £500.
Quick reference
- NHBC covers windows and doors for non-structural defects for exactly two years from the home completion date.
- Structural defects like wall collapse are covered for 10 years, but windows and doors are not classed as structural components.
- You must report window or door defects to your housebuilder in writing before the two-year anniversary to qualify for NHBC cover.
- Manufacturer guarantees for windows typically last 10 years but only cover material or manufacturing faults, not installation errors.
- After two years, a failed sealed unit replacement costs £300 to £600 for a standard double-glazed window in the UK.
Frequently Asked Questions
Windows are covered for non-structural defects for up to two years under the NHBC Buildmark warranty. After that, rely on the manufacturer's guarantee, typically lasting 10 years.
Yes, condensation between glass panes is covered as a non-structural defect within the first two years. Report it to your builder per NHBC guidelines.
Items like windows and doors are not covered for structural defects beyond two years. The NHBC Buildmark excludes general wear and tear, and cosmetic issues after the initial period.
