“That’s within tolerance” — what a builder actually means
The NHBC standards, viewing distances and when to stand firm.
6 min readWhat “within tolerance” actually means
At some point during snagging, you’ll point at something and be told it’s “within tolerance” or “acceptable.”
It’s worth understanding exactly what that phrase means, because it isn’t the builder’s personal opinion — they’re referring to published industry standards, and knowing those standards is how you tell a genuine fob-off from a fair one.
When a home is built it’s inspected against the standards of its warranty provider — usually NHBC (National House Building Council) or LABC (Local Authority Building Control). The NHBC publishes a document called A Consistent Approach to Finishes, which sets out measurable tolerances for the finish of a new home. When a builder says “within tolerance,” they mean it falls inside the limits set out in that document.
The key thing to understand — and this catches almost everyone out — is the viewing-distance rule. Many of these standards are judged not from up close, but from a set distance, in daylight, with the lights off.
The viewing-distance rules
- Glass
- Checked in daylight from at least 2 metres away (3 metres for toughened, laminated or coated glass), looking straight through. Fine scratches up to 25mm long are deemed acceptable if they’re not obtrusive or bunched together. Minor scratching within 6mm of the edge of the pane is also allowed.
- Paintwork, walls and ceilings
- Generally viewed from 2 metres in daylight — and the standard explicitly says with wall lights and uplighters switched off.
- Brickwork and external walls
- Judged across the whole wall from around 10 metres, not brick by brick.
- Factory-finished doors and window frames
- Scratches judged from 0.5 metres.
- Sanitary ware
- Baths, basins and shower trays — scratches and chips judged from 0.5 metres.
Specific figures builders lean on
- Walls
- Can be up to roughly 8mm out of plumb (out of vertical) over a storey height, and similar out of line over a 5m run.
- Cracks
- Up to 2mm wide in general wall surfaces are considered normal shrinkage — treated as homeowner maintenance to fill, not a builder defect. Up to 4mm is allowed where a staircase string meets a wall.
- Floors
- Can be out of level by several millimetres per metre, which across a wide room can add up to a surprising total and still be “within tolerance.”
- Skirtings and trim
- Gaps appearing at skirtings and between trim and wall from timber drying out are expected, and are treated as homeowner maintenance.
The honest takeaway
“Within tolerance” is a real, published benchmark — it’s not made up, and a fair builder isn’t lying to you when they use it.
But it’s also the industry’s minimum acceptable standard, not a measure of good work, and it does get used to wave away things that could reasonably be put right.
Two practical lessons fall out of this:
- Inspect at the distance the standard uses, then decide for yourself. If a scratch or a crack only disappears when you stand back 2 metres and turn the lights off, expect the “within tolerance” answer. If it’s still obvious at that distance — or it’s something the standards don’t allow to be fobbed off, like a non-working socket, a leak, a door that won’t close, or unsealed silicone — stand firm. Those aren’t tolerance questions, they’re defects.
- The viewing-distance rule is exactly why scratched glass and paintwork matter so much when you snag — they’re the two areas where the standards give the builder the most room, so they’re the two areas where your careful, close, in-the-right-light inspection makes the biggest difference to what ends up on the list.
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