Common BCA rejection reasons

Inspection rejections are strikingly repetitive: the same short list of items on job after job, across every council. Almost all share one trait — they’re easy to get right and easy to hide (a half-nailed brace, a missing DPM lap, a flashing under-lapped), so they only surface when an inspector goes looking. Know the list and you can self-check before you cover anything up.

Structural fails: bracing, plates and straps

The stuff that carries load is what inspectors scrutinise hardest, and it’s where toenails-instead-of-straps and short fixings get pulled up.

• Bracing element short of required BU/m. Fails when stud spacing is wrong, a sheet is missing its hold-down, or a sheet is under the 400mm minimum length. Fix: add another bracing element or upgrade an existing one (for example BL1-H over GS1-N for more BU), then re-submit the EzyBrace calc.
• Bottom plate fixing under the required kN. Fails when anchors are too few or too far apart, or an anchor is missing within 150mm of the plate end. Fix: drill and chemical-anchor more, especially near the end of the plate.
• Missing strap-tie on the truss heel. Fails when toenails are substituted and the uplift kN isn’t met. Fix: add a Pryda CS400/500 strap each face, nailed through the bottom chord and top plate.

Weathertightness: DPM, underlay, flashings and cavity

This is the biggest cluster of repeat fails, and the one that costs the most later if it slips through.

• DPM missing or torn before the pour. Fails when trades walk on the DPM with no protection layer. Fix: replace the torn section and tape the laps — don’t backfill over a rip.
• Roof underlay not overhanging the fascia. Fails when it’s cut flush with the fascia instead of overhanging 20–25mm. Fix: extend it with peel-and-stick tape or replace the last metre.
• Wall underlay with UV exposure over 90 days. Fails when cladding install is delayed and the underlay degrades. Fix: cover it with weatherproof sheeting, or replace it — once degraded it won’t perform.
• Flashings at 0.55mm in Zone D. Wrong spec — Zone D needs 0.7mm. Fix: replace the flashings; 0.55 will corrode through within 5 years.
• Cavity batten under 18mm, or no top vent. Fails with an off-spec batten or capping mortar at the top of the cavity. Fix: replace the batten, or drill weep holes at the top of the cavity.

Insulation, wet areas and services

The finishing trades trip on these — small gaps and omitted parts that an inspector will still find.

• Insulation gaps or settling. Fails from poor fit around services, edge bunching, or settling over time. Fix: get a fluffy fit corner-to-corner with no gaps — use staples or rigid backing if needed.
• Wet-area gap at the floor missing. Fails when GIB butts to the floor with no membrane upturn. Fix: cut back a 10mm gap at the base so the membrane can upturn behind the sheet.
• Tempering valve missing or set over 55°C. Fails when the plumber omits it, or it’s factory-set above 55. Fix: install or adjust the TMV and test the outlet temp with a thermometer.
• Smoke alarms of the ionisation type. Fails when an old or wrong unit is fitted. Fix: replace with photoelectric, hardwire to a dedicated circuit, and interconnect.

The one habit that prevents most of these

Take dated photos of everything before you cover it — bracing nailing, hold-downs, DPM, flashings and pipe penetrations. It lets you self-check before the inspector arrives, and gives you the evidence if a question comes up later.