Woodwork
Skirting and architrave paintable area
- where
- skirting area (m²)
- length of skirting (m)
- skirting girth (mm)
- architrave area (m²)
- architrave sets
- architrave leg length (m)
- architrave head length (m)
- architrave girth (mm)
- total area (m²)
- paint per coat (L)
- spreading rate (m²/L)
Explain this equation
Works out the area of skirting and architrave to paint, and the paint for one coat.
Skirting area is its length times its girth, the width of painted surface measured round the face and top edge, converted from mm. Each set of architrave has two legs and a head. Adding both and dividing by the spreading rate gives litres per coat.
Length times girth for each moulding.
Sense check: 15 m of 170 mm girth skirting is 2.55 m²; two architrave sets add about 0.8 m²; about 0.2 litres per coat.
Watch out: measure the girth round the moulding with a tape, not just the height of the board.
Turns lengths of skirting and architrave into a paintable area by multiplying by the girth painted.
Enter your values to see the result.
Good to know
Girth is the distance round the painted surface: for skirting, the face height plus the top edge (e.g. 145 mm board, 18 mm thick, about 165–170 mm). NRM 2 measures narrow surfaces up to 300 mm girth in linear metres, which this converts to area so it can feed a paint quantity. Architrave sets are counted per face of each door opening.
Common mistake
Using the board height without the top edge and moulding, which underestimates the area.
Limits
Straight runs. Very ornate profiles have a larger girth: measure round them with a tape.
Sources
- RICS NRM 2 Detailed measurement for building works, Work section 29 Decoration (area or girth measured is that covered; frames measured edge to edge; ≤ 300 mm and > 300 mm girth; radiators by type)
- Dulux Trade Undercoat data sheet (up to 17 m²/L; 1 coat undercoat then 1 or 2 coats of High Gloss; 1, 2.5, 5 L)
- Geometry: rectangle and cylinder surface areas, prism volumes
Results are calculations from the published methods and figures shown, and depend on the data you enter. Coverage depends on the product, surface and application. Always follow the paint and wallcovering manufacturers’ data sheets and BS 6150 / BS 8000-12. Check prices and VAT with your own records and HMRC.