Question 1

How many square metres does a litre of emulsion cover?

Accepted Answer

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.

Question 2

How much paint do I need for a room?

Accepted Answer

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.

Question 3

Does surface type affect paint coverage?

Accepted Answer

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.

Question 4

What is the coverage rate for masonry paint?

Accepted Answer

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.

Question 5

Should I use a mist coat on new plaster?

Accepted Answer

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.

Paint Type	Smooth Plaster (m²/L)	Bare Plaster (m²/L)	Textured Surface (m²/L)	Coats Required
Matt emulsion	12-14	8-10	6-8	2
Silk emulsion	10-12	7-9	5-7	2
Eggshell (water)	12-14	8-10	6-8	2
Kitchen/bathroom	11-13	7-9	5-7	2
Mist coat (70:30)	-	12-15	-	1

Paint Type	Prepared Surface (m²/L)	Bare Timber (m²/L)	Coats Required
Gloss (oil-based)	14-16	10-12	1-2
Satinwood (water)	12-14	8-10	2
Primer/undercoat	12-14	8-10	1-2
Wood stain	-	10-15	2-3
Varnish (polyurethane)	14-16	8-12	2-3

Paint Type	Smooth Render (m²/L)	Rough/Pebbledash (m²/L)	Coats Required
Smooth masonry	10-12	4-6	2
Textured masonry	4-6	3-5	2
Stabilising solution	5-8	3-5	1
Exterior wood (fence paint)	-	6-8	2

Paint Coverage m²/Litre by Type and Surface

Interior Paint Coverage Rates

Wood and Metal Paint Coverage

Exterior Paint Coverage

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