How to prove it’s a build defect

— not “maintenance”

When you report a fault, some builders reach for the same defence: “that’s a maintenance issue.” In practice, it often falls to you to show it isn’t. With the right evidence, that’s very doable. Here’s how.

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The golden rule: timing

A maintenance issue develops gradually, through normal use, over years. A build defect is present from the start, appears early, or keeps coming back. If you can show it existed at — or shortly after — handover, the “maintenance” line collapses: a brand-new home shouldn’t need significant maintenance in its first couple of years.

Your evidence toolkit

Dated photos from day one. Photograph every fault and its progression, with the date visible or in the file metadata. A timeline is hard to argue with.

A professional snagging survey at handover. The single strongest proof — an independent, dated expert report listing defects present from the start. If it’s on that report, it isn’t wear and tear.

An independent expert on the cause. A chartered (RICS) surveyor, structural engineer or damp specialist can diagnose why it’s happening. Cause is what separates a build defect (workmanship, materials, design) from maintenance or lifestyle.

Show it breaches a standard. If the work doesn’t meet building regulations, the build specification, or NHBC technical standards, it’s a defect by definition. Name the standard it falls short of.

Pattern and recurrence. A fault that returns after “repair”, or that neighbours on your estate also have, points to a systemic build defect — not individual neglect.

The “missing provision” rebuttal. For condensation/damp: if extractor fans or trickle vents are missing, undersized or don’t work, the “you didn’t ventilate” excuse fails — adequate ventilation wasn’t built in.

Everything in writing, dated. Report in writing (never just a phone call). A contemporaneous, dated paper trail is evidence in itself.

Turn the question back on them: ask the builder to state exactly what maintenance you supposedly failed to carry out, and how it would have prevented this fault. They usually can’t — routine upkeep doesn’t cause workmanship or structural defects.

The practical playbook

✓Capture dated photos the moment you spot something.
✓Get an independent survey or expert report on the cause where it matters.
✓Reference the building regulation, spec or NHBC standard it breaches.
✓Report it to the builder and your warranty provider in writing, within your cover period.
✓Log it on Snag Scout so your timeline and evidence are captured and on the record.
✓If they still refuse, escalate to your warranty provider or the New Homes Ombudsman.

On cost

You’ll usually pay for an independent survey upfront — but if it proves a defect, that report is powerful leverage with the builder, your warranty provider and the Ombudsman, and the cost can sometimes be recovered. Treat it as an investment in getting the fault put right.

Build your case — and put it on the record.

Log your defect and evidence free on Snag Scout — verified, dated, and impossible to quietly ignore.

Share your experience

This guide is general information, not legal or professional advice, and does not override your warranty terms or contract. Your warranty provider or the Ombudsman will weigh the evidence on its merits. If in doubt, take professional advice.