Beads, coving and sundries
Textured coating (Artex) bags and water
- where
- bags needed, unrounded
- area to texture (m²)
- waste allowance (%)
- coverage per bag from the datasheet (m²)
- whole bags to buy
- powder needed (kg)
- bag weight (kg)
- water per full bag (litres)
- initial mix water per bag (litres)
- extra water per bag for the texture (litres)
- total water (litres)
Explain this equation
This works out bags of powder textured coating, such as Artex, and the water to mix it for a textured ceiling or wall.
C is the coverage per bag from the datasheet, which depends on the pattern. Wi is the water for the initial mix and Wa the extra water added to suit the texture: more for a light stipple, less for a rich swirl or comb.
Bags follow from area plus waste divided by coverage, rounded up. Water per bag is the two additions together, and the total water is scaled by the exact (unrounded) number of bags you will mix.
Sense check: a 20 m² ceiling at 30 m² per bag needs under one 25 kg bag even with waste, mixed with about 16 litres of water for a stipple.
Watch out: old textured coatings may contain asbestos. Have them tested before disturbing them.
Bags of powder textured coating and the water to mix it, for a ceiling or wall texture.
Enter your values to see the result.
Good to know
Artex Textured Finish (25 kg): texture finishing about 30–50 m² per bag. Mix with about 11 L of water per 25 kg, then add about 5 L more for a light texture such as stipple, or about 2.5 L for a rich texture such as swirl or comb. Heavier patterns use the lower coverage. Seal porous backgrounds first as the maker directs.
Common mistake
Pricing a deep swirl or comb pattern at the best-case 50 m² per bag.
Limits
Coverage depends on pattern depth and background. Older textured coatings may contain asbestos: have them tested before sanding, scraping or over-coating preparation.
Sources
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the manufacturers’ system and product data, BS 8212, BS EN 13914 and Building Regulations. Coverage rates vary by product, background and thickness. Check prices, VAT and CIS rules with your own records and HMRC.