Flooring & Screeds
QA inspection checklist

Substrate & Screed

1. 1.

   DPM installed and sealed
   What to look forDPM continuous across slab area, lapped to wall DPC. Min 1200 gauge polyethylene typical, sealed at all laps. No tears, punctures from rebar or trafficking. Up-stand at perimeter to within finished floor level.
   Acceptable whenDPM to BS 8102:2022 (waterproofing) / BS 6515 (polyethylene sheet). Minimum 1200 gauge (300 μm) for ground floor. Laps ≥ 150 mm, taped or welded. Continuous with wall DPC.
   StandardBS 8102:2022 — Protection of below-ground structures from water ingress. BS 6515:1984 — Polyethylene damp-proof courses. NHBC Standards 5.2.
   Common defectsDPM punctured by reinforcement — visible holes after rebar fixingLap unsealed — capillary pathDPM not lapped to wall DPC — ground moisture rises at junctionWrong gauge — 1000 gauge in residential where 1200 neededNo upstand at perimeter — moisture wicks at edges
2. 2.

   Screed depth correct

   Record: Depth (mm)
   What to look forProbe or core to confirm depth. Bonded screed minimum 25 mm; unbonded minimum 50 mm; floating (over insulation) minimum 65 mm domestic, 75 mm commercial. UFH screed minimum 50 mm above pipe (sand-cement) or 30 mm (anhydrite).
   Acceptable whenPer BS 8204-1:2003+A2:2011: bonded ≥ 25 mm, unbonded ≥ 50 mm, floating ≥ 65 mm (domestic) / 75 mm (commercial). UFH cover: SR1 sand-cement ≥ 65 mm above pipe, anhydrite ≥ 30 mm above pipe.
   StandardBS 8204-1:2003+A2:2011 — Concrete bases and cementitious levelling screeds. BS 8204-7 (pumped self-smoothing). NHBC Standards 8.3.
   Common defectsFloating screed too thin — fails under point loadBonded screed too thick — debonds and curlsUFH cover insufficient — pipe profile shows through finishInconsistent depth across area — finish tolerances exceededScreed thinner than minimum at door openings to clear thresholds
3. 3.

   Levels correct

   Record: Deviation (mm)
   What to look forLevels surveyed to design FFL. Surface regularity (SR) class verified with 3 m straight edge or 3 m surveyors level. SR1 for high-spec finishes (vinyl, rubber, sport), SR2 normal, SR3 industrial. Check at multiple points.
   Acceptable whenPer BS 8204-1: SR1 = ±3 mm in 3 m, SR2 = ±5 mm in 3 m, SR3 = ±10 mm in 3 m. Datum to design FFL ±15 mm typical. Falls to drains 1:80 minimum (kitchens, wet areas).
   StandardBS 8204-1:2003+A2:2011. BS 8203:2017 — Installation of resilient floor coverings. Concrete Society TR34 (industrial floors).
   Common defectsSR2 achieved where SR1 specified — vinyl will telegraph defectsFalls to drains insufficient — water poolsLocal high spots — power floating unevenDatum not held — finished floor too high or low at thresholds
4. 4.

   Moisture content acceptable

   Record: MC (%RH)
   What to look forHygrometer (relative humidity) test in sealed dome on slab — preferred method for drying. Carbide bomb (CM) for fast indication. Test only after screed has had drying time (1 mm/day for first 50 mm, then half rate).
   Acceptable whenPer BS 8203 / BS 5325: ≤ 75% RH for resilient floor coverings (vinyl, rubber); ≤ 65% RH for moisture-sensitive (some adhesives, wood). Carbide bomb ≤ 4% (sand-cement), ≤ 0.5% (anhydrite). Drying time approx 1 mm/day for first 50 mm.
   StandardBS 8203:2017 — Installation of resilient floor coverings. BS 5325:2001 — Installation of textile floor coverings. CFA Guidance.
   Common defectsVinyl laid before screed dry — blistering and adhesive failureTest taken from surface only — not representative of bulkNo hygrometer test — only visual inspection usedAnhydrite screed laid with cementitious adhesive — chemical attackDrying time underestimated — programme pressure overrules test

Floor Finish

1. 5.

   Finish type and colour match specification
   What to look forFinish matches the approved sample/datasheet — colour, gauge, wear class, slip resistance class. Batch numbers consistent across same area. Pile direction (carpet) consistent. PUR/polyurethane coating where specified for cleanability.
   Acceptable whenVinyl/LVT to BS EN 649 / BS EN 14041. Wear class T (heavy) or 32+ for commercial. Slip resistance R10/R11 minimum (BS 7976 PTV ≥ 36). Carpet to BS 5808 with required wear class. Same batch across visual area.
   StandardBS EN 14041 — Resilient, textile and laminate floor coverings — essential characteristics. BS 7976-2 — Pendulum test for slip resistance. BS 8425 (carpet selection).
   Common defectsDifferent batch numbers — visible colour/shade bandingWrong wear class for traffic — domestic LVT in commercial space, wears in monthsSlip resistance below R10 in wet area — fall hazardPile direction varies tile to tile — visual patchworkDamaged or curled tiles installed regardless
2. 6.

   Joints tight and aligned
   What to look forJoints between sheets/tiles tight to each other — no visible gap. Joints aligned in straight runs. Heat-welded joints (commercial vinyl) flush, no overcut grooves. Tile patterns aligned across rooms and through doors.
   Acceptable whenPer BS 8203: vinyl/LVT joint < 0.5 mm gap, sheet vinyl with hot-weld rod flush ±0.2 mm. Tile cuts at perimeter ≥ ½ tile width. Pattern through doors aligned within 5 mm.
   StandardBS 8203:2017. BS 8425:2003 (carpet). FFB Code of Practice.
   Common defectsOpen joints between LVT — debris fills, looks dirtyHot-weld rod proud — trip hazard on commercial vinylJoint groove cut too deep — weld weakPattern misaligned through doorways — installer set out by roomTiles cut < ¼ — looks unbalanced
3. 7.

   Threshold strips and edge details complete
   What to look forThresholds at all changes in finish (carpet to vinyl, room to corridor). Strips chosen to suit (Z bar, T bar, ramp, Schluter). Sealed edges at wet areas — coved skirting or sealant. No visible edge of substrate.
   Acceptable whenThreshold types per BS 8425 / FFB guidance. Wet area cove skirting min 100 mm up wall, fully bonded. Approved Document M Part M ramp gradient ≤ 1:12 for changes in level > 5 mm.
   StandardBS 8203:2017. Approved Document M (Access). BS 5395-1 (level changes).
   Common defectsNo threshold at carpet/vinyl junction — carpet fibres trappedBare substrate visible at edge of finishWet area skirting not coved — water tracks behindWrong threshold type — Z bar where ramp needed for accessibilityThreshold not fixed — rocks under foot traffic
4. 8.

   No damage or defects
   What to look forInspect under raking light. No scratches, scuffs, dents, or stains. Adhesive squeeze-out cleaned. No tile lifts or hollow spots (tap test). Protection in place during follow-on works.
   Acceptable whenSurface defect-free under normal viewing (1 m at 90°). Tap test reveals no hollows. Per BS 8203 / FFB: surface clean, free from damage. Final clean and protection per programme.
   StandardBS 8203:2017. FFB Code of Practice. BS 8425.
   Common defectsFootprints in adhesive — installer walked on bedded LVT before setHollow tiles — adhesive coverage < 95%Stains from follow-on trades — paint, plaster, brick mortarTile lifted from substrate — adhesive incompatible or screed too dampDamage from re-keying tools or skips dragged across

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