What is a latent defect?
A latent defect is a defect that could not have been discovered by a reasonable inspection at the time of completion, usually because it is hidden inside the work: a membrane under tiles, a missing fire collar above a ceiling, reinforcement without cover inside a slab. Its opposite is a patent defect, one a reasonable inspection would find, like a chipped tile or a door that does not latch. The distinction matters because the clock on a latent defect is argued from when it was, or could have been, discovered rather than from completion, and the statutory periods that still apply years after the contractual defects liability period differ by state. What settles a latent-defect claim is the record: when the work was done, by whom, what was inspected, and when the fault first showed.
Nobody could have seen it. Somebody still has to prove when it started.
A latent defect is the one case where “you should have found it at handover” is not the answer, and that cuts both ways. The owner cannot be blamed for not lifting the tiles; the builder cannot be blamed on the strength of a stain that appeared nineteen months after anyone last looked. So the argument moves to dates. When was the membrane laid, by which trade, and did anyone inspect it before it was tiled over? When did the stain first appear, and when was the builder told? Every one of those is a fact that either exists on a record made at the time or does not exist at all.
Four defects, two kinds
The record that was made before anyone knew it mattered
The evidence for a latent defect is mostly made during the build, by people who did not know they were making it. The hold point on the waterproofing, answered Yes by a named inspector on a date, with the certificate sighted. The pre-pour check on the reinforcement, with the cover-meter log. The photo of the riser before the ceiling closed, with its original device timestamp. None of that was taken for a claim; it was taken because the checklist asked. Nineteen months later it is the only account of what was inside the wall. When the stain appears, the owner’s report arrives as a record against the lot with its own photo and date, typed Warranty, issued to the builder with the email on the trail. The two records, the one from the build and the one from the stain, sit on the same register, and the history view reads them in order: who did what, when, with what evidence.
Asked alongside this one
Where this answer comes from
The docs behind this answer are inspections (hold points), photos and annotations and defects. The statutory periods that outlast the contractual DLP, state by state and sourced, are on defects liability periods in Australia; what makes the record itself hold up is what makes a defect record stand up in a dispute? General information, not legal advice: the contract and your state’s law decide how a latent defect is treated.