Woodwork
Undercoat and gloss for woodwork
- where
- undercoat, one coat (L)
- woodwork area (m²)
- undercoat spreading rate (m²/L)
- waste and touch-up allowance (%)
- gloss (L)
- coats of gloss
- gloss spreading rate (m²/L)
Explain this equation
Works out the undercoat and gloss needed for a woodwork job.
One coat of undercoat covers the area at its spreading rate. Gloss is applied in N_g coats at its own rate. Both get the same waste allowance.
Coverage arithmetic: litres equal area times coats divided by spreading rate.
Sense check: 12 m² of woodwork needs about 0.8 litres of undercoat and about 1.5 litres of gloss for two coats.
Watch out: small quantities spread over many fiddly surfaces always use more than the rate suggests. Round up to the next tin.
Works out undercoat and gloss for a woodwork system of one undercoat and one or two gloss coats.
Enter your values to see the result.
Good to know
Dulux Trade gives up to 17 m²/L for its undercoat and up to 18 m²/L for High Gloss on smooth surfaces, with one coat of undercoat then one or two of gloss (two on rough surfaces). Woodwork areas come from the door, skirting and window calculators. Small areas still need a full tin of each colour: 1 L is the smallest trade size.
Common mistake
Assuming one gloss coat over a big colour change. Use a coloured undercoat matched to the topcoat, and plan for two gloss coats on bare or rough timber.
Limits
Primer for bare timber is separate. Water-based satin and eggshell systems often use primer-undercoat plus two topcoats: enter the topcoat as “gloss”.
Sources
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.