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Major defect

A major defect affects a building's structure, safety or use and carries the longer statutory warranty period (6 years in NSW, versus 2 years for other defects).

By Dan Waring. Last updated 3 June 2026. Verified 3 June 2026.

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A major defect is a defect that affects a building’s structural performance, safety, or the ability to use the building for its intended purpose. It carries the longer statutory warranty period, for example 6 years under the NSW Home Building Act and HBCF, versus 2 years for other (minor) defects. The classification is what sets a builder’s warranty exposure.

Statutory warranties run for two periods: a longer one for major defects and a shorter one for everything else. Roughly, a major defect is one that:

  • affects a major element of the building (load-bearing structure, the parts that hold it up or keep it standing),
  • makes the building (or part) uninhabitable or unable to be used for its purpose,
  • threatens collapse or safety, or
  • involves serious waterproofing failure (water penetration is specifically treated as major in several states).

Everything that does not meet that bar (cosmetic cracking, a sticking door, minor finishes) is a non-major defect with the shorter warranty.

The numbers vary by state, but the NSW structure is the common reference: 6 years for major defects and 2 years for other defects, running from completion. The distinction matters because a claim made inside the major-defect window is live even years after handover, while the same claim for a minor defect would be out of time.

For a builder the practical points are that your real liability tail is the major-defect period, so structural and waterproofing work is where careful execution and records pay off for years. For an owner, identifying whether a problem is a major defect determines whether you still have a claim: a structural or waterproofing issue discovered in year four is generally still claimable in NSW, where a cosmetic one is not.

Also known as: Structural defect (loosely), major element defect.

Category: Contracts / Warranty.

See also

References

Last updated: 2026-06-03. Verified: 2026-06-03. Quarterly review for currency.

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