Pre-plaster inspection checklist
The last honest look at everything that gets buried. Once boards are on, every one of these becomes a demolition job.
Short answer
A pre-plaster inspection confirms first fix mechanical and electrical, structural fixings, insulation continuity, airtightness sealing, fire stopping and noggins are complete and correct before plasterboard closes them in. It is evidence-led: photograph every wall and ceiling zone before boarding, because nothing is re-inspectable afterwards.
Key figures
| Requirement | Value | Basis |
|---|---|---|
| Notch depth in a joist | max 0.125 x joist depth, in the 0.07-0.25 span zone | Approved Document A |
| Hole diameter in a joist | max 0.25 x joist depth, on the neutral axis | Approved Document A |
| Hole spacing | at least 3 diameters apart, centre to centre | Approved Document A |
Why this stage carries so much risk
Almost every expensive defect on a housing site is something that was correct on the drawing, wrong on site, and then boarded over. Pre-plaster is the single inspection where the cost of finding a fault is measured in minutes rather than in ceilings taken down.
Structure and carpentry
- Joist notches and holes within the permitted zones and sizes.
- Noggins fitted for every board edge, and for sanitaryware, handrails, TV brackets and radiators.
- Restraint straps fixed, with packing behind and fixings into solid timber.
- Loadbearing studs and heads correct, no cut top plates.
Services first fix
- Cables in safe zones and protected where they pass through studs and joists.
- Pipework pressure-tested and the test recorded, not just "it looked fine".
- Soil and waste falls correct and pipe clips complete before boarding.
- Extract ducting continuous, insulated in cold zones and terminating at an external outlet, never into a void.
Thermal, airtightness and fire
- Insulation continuous with no gaps at eaves, at joist ends and behind service runs.
- Airtightness membrane or wet plaster parge coat continuous at junctions and around penetrations.
- Fire stopping complete at compartment lines, including around service penetrations and at the head of separating walls.
- Socket boxes and downlights sealed where they penetrate an airtightness or fire line.
Evidence
Photograph each room wall by wall and the ceiling void before boards. Name each photo by plot, room and elevation. That set is the evidence pack for warranty inspection, for the BREL report, and for any later dispute about what was actually built.
How to check it
- Book the inspection before boards are on site. Schedule the check while access to every void is still open, not on the morning the boarders arrive.
- Walk the plot room by room. Work in a fixed order so nothing is skipped: structure, then services, then thermal, then fire.
- Photograph every zone. Capture each wall and the ceiling void, with plot and room identifiable in the file name.
- Raise and close defects. Log each fault against the trade responsible, then re-photograph the corrected work before releasing the plot for boarding.
Common questions
Who should carry out the pre-plaster inspection?
Normally the site manager or a quality inspector, with the M&E contractor available to confirm first fix. On warranty inspections, the pre-plaster stage is also a common key stage visit.
What happens if the plot is boarded before the inspection?
The honest answer is that the evidence is gone. Expect openings to be cut for spot checks, or the work to be accepted on risk with no photographic record — which is exactly the position that costs money later.
Is a pre-plaster check the same as a Building Control inspection?
No. An internal quality inspection is not building control, warranty determination or statutory approval. It is your own check that the work is right before it is covered up.
Basis in regulation
Last reviewed 2026-08-21.