Painting Takeoff per BS 6150 — Areas, Deductions, and Coats
A painting takeoff is area × coats ÷ coverage. The judgement is in how you measure the area — flat, girthed, or by a multiplier.
Measure the net surface
Measure the actual painted surface. For plastered CHB walls that is the wall face; for a coffered or profiled ceiling it is the developed (girthed) area, not the flat projection.
Deduction rules (BS 6150 practice)
| Opening size | Treatment |
|---|---|
| ≤ 0.5 m² | No deduction (reveal and edge painting offsets it) |
| 0.5–3.5 m² | Deduct one face; add reveals and soffit |
| > 3.5 m² | Deduct both faces; measure reveals separately |
Irregular surfaces — girth multipliers
| Surface | Multiplier on measured area |
|---|---|
| Panelled / moulded doors | × 1.5–2.0 |
| Railings, balusters, grilles | × 1.5–3.0 (or measure by weight/height) |
| Corrugated roofing sheet | × 1.1–1.2 |
| Trusses / open steelwork | by m²/tonne from the steel tables |
Coats and coverage
Add 5–10% waste; more for spray application and rough surfaces
A typical system is one primer/sealer + two finish coats. Price primer, undercoat, and finish separately — they have different rates and costs.
EngEst Pro’s Painting Calculator takes off surfaces with gross/deduct areas per BS 6150, applies the coating system per surface, and outputs primers, finish coats, sundries, and labour as a priced BOM.
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