Paint Coverage m²/Litre by Type and Surface

Matt emulsion typically covers 12-14 m² per litre on smooth plaster or plasterboard. On bare plaster (first coat), coverage drops to 8-10 m² per litre as the porous surface absorbs more paint. Silk and satin emulsions cover slightly less at 10-12 m² per litre. These are manufacturer-quoted rates for one coat — always apply at least two coats for a solid finish, especially when changing colour.

For a typical 4 x 4 m room with 2.4 m ceiling height: the walls are approximately 38 m² (minus about 4 m² for door and window = 34 m²), and the ceiling is 16 m². At 13 m² per litre for emulsion, you need approximately 2.6 litres for one coat on walls. For two coats on walls and ceiling, you need approximately 7.7 litres total — so two 5-litre tins with some left over for touch-ups.

Yes, significantly. Smooth sealed surfaces (previously painted plaster) give the best coverage. Rough or textured surfaces (Artex, roughcast, pebbledash) can reduce coverage by 30-50%. Bare plaster absorbs heavily on the first coat, reducing coverage by 20-30%. New timber requires primer and undercoat before topcoat. A mist coat (diluted emulsion) on new plaster prevents flaking and improves subsequent coverage.

Smooth masonry paint covers approximately 10-12 m² per litre on smooth render. Textured masonry paint covers 4-6 m² per litre due to its thicker consistency. On rough or pebbledash surfaces, coverage can drop to 3-5 m² per litre. Most masonry paints require two coats, and a stabilising solution should be applied first to chalky or powdery surfaces.

Yes. A mist coat is essential on new plaster to prevent the topcoat from peeling. Mix matt emulsion with water at approximately 70:30 (paint:water) ratio. Do NOT use vinyl or silk emulsion for the mist coat as they form a skin that can peel. Wait until the plaster is fully dry (typically 2-4 weeks depending on conditions) before applying the mist coat, then follow with two full-strength coats.