Guides · Snagging checklist
What to check outside and in every room, the NHBC tolerances builders work to, when you have the right to inspect, and how to record each snag so it gets fixed first time.
By ARX Algorithms, makers of SnagAudit · Updated 1 October 2026
A snag is anything in a new or refurbished home that is unfinished, damaged or not built to the expected standard: a paint run, a door that sticks, a cracked tile, missing mastic round a bath, a gutter that drips. Snagging is the walk-round that finds them, records each one clearly and hands the list to the builder to put right.
New homes are rarely perfect. One widely reported industry figure put the average at 157 snags per new-build home (BuildScan, reported in 2021, up from 80 in 2005). Most are small. The point of a good snag list is that every one of them is described precisely enough, and photographed well enough, that nobody can argue about what was meant or whether it was there before.
Most new homes in England are built by developers signed up to one of two consumer codes, and both give you a chance to inspect before you complete.
In short: snag before completion if you can, snag again in the first few weeks of living there, and do a final check before the end of year two.
Whether something is a snag often comes down to a measurement. NHBC's Standards (Chapter 9.1, "A consistent approach to finishes", 2024 edition) set out what most warranty providers and developers accept. Finishes are judged from about 2 metres away in normal daylight, not with a torch held against the wall.
| Element | NHBC tolerance |
|---|---|
| Internal walls, plumb | Up to 8 mm out of plumb for walls up to 3 m high |
| Internal walls, flatness | ±3 mm under a 2 m straight edge |
| Ceilings, level | Within 3 mm per metre (ceilings up to 6 m across) |
| Ceilings, flatness | ±5 mm under a 2 m straight edge |
| Cracks at wall, floor and ceiling junctions | Up to 2 mm wide may occur through drying shrinkage |
| Floors | Level within 3 mm per metre (up to 6 m across); flat within ±5 mm under a 2 m straight edge |
| Skirting to floor finish | Gap no more than 5 mm |
| Internal doors | Gap at head and sides no more than 4 mm; 10 to 22 mm under the door to an unfinished floor |
| Window heads, sills and reveals | Within 3 mm for openings up to 1.5 m (5 mm if larger) |
| Wall and floor tiling | Flat within ±3 mm over 2 m; lips between tiles no more than 1 mm (joints up to 6 mm) or 2 mm (wider joints) |
| Glazing | Viewed from 2 m (3 m for toughened or laminated glass); fine scratches up to 25 mm long acceptable if not obtrusive |
| External brickwork | Up to 8 mm out of plumb per storey (up to 3 m); ±8 mm straightness over 5 m |
| Paintwork | Free from conspicuous runs and prominent brush marks |
Anything outside these figures is worth recording with a measurement and a photo that shows the straight edge or tape in shot. Check the current edition of the NHBC Standards if a dispute turns on a number.
Work methodically: outside first while the light is good, then room by room, top floor down, clockwise round each room. Look at every surface, open and close everything, and run every tap and appliance.
That is exactly the workflow SnagAudit's snagging app is built around: one item per snag, photos with mark-up, trade and status, and a numbered PDF snag list you can hand over before you leave the site.
Before completion if the developer allows it, and both main consumer codes say they must offer you the chance: under the New Homes Quality Code and the Consumer Code for Home Builders you can inspect, or send a professional, after the notice to complete and before legal completion. Snag again in your first weeks in the home and before the end of the two-year builder warranty period.
A widely reported industry figure put the average at 157 snags per new home (BuildScan, 2021). Most are cosmetic, such as paint runs, sealant gaps and door adjustments, but each one is worth recording with a photo.
The New Homes Quality Code allows the NHQB pre-completion checklist to be completed digitally, as long as it carries out the same checks as the official template. A snagging app is ideal for recording, photographing and sharing everything you find alongside it.
Most UK developers and warranty providers follow NHBC Standards Chapter 9.1. For example, internal walls should be flat within plus or minus 3 mm under a 2 m straight edge, and the gap under skirting should be no more than 5 mm.
Under NHBC Buildmark, the builder is responsible for putting right defects reported in the first two years. Report them as soon as you find them, in writing, with photographs.