Emulsion Paint: Finishes, Brands, and How to Get a Good Result on New Plaster

Skip the mist coat on new plaster and you'll be scraping paint off in sheets within six months, then paying your decorator to do the whole room again. It's the single most expensive painting mistake homeowners make on extension and renovation projects, and it's entirely avoidable. This page covers everything you need to know about emulsion paint: which finish to choose, which brands are worth the money, how to calculate quantities, and how to get a professional result on freshly plastered walls.

What it is and what it's for

Emulsion paint is water-based paint used on internal walls and ceilings. "Emulsion" refers to the way the paint is made: tiny droplets of acrylic or vinyl resin suspended in water. When you brush or roll it on, the water evaporates and the resin particles fuse together to form a continuous film. Because the carrier is water rather than solvent, emulsion paints dry fast (typically touch-dry in one to two hours), clean up with water, and produce very little odour compared to oil-based paints.

UK regulations cap the VOC (volatile organic compound) content of interior matt emulsion at 30 g/L for water-based formulations under the Volatile Organic Compounds in Paints Regulations 2012. Every emulsion you'll find at Screwfix, Toolstation, B&Q, or Wickes comfortably meets this limit. "Low VOC" on the tin is marketing, not a meaningful differentiator, because they're all low VOC by law.

Two coats over a properly primed surface is the standard. Not one. Two.

Finishes: which one goes where

The finish you choose affects how the paint looks, how it wears, and how forgiving it is of imperfect plaster. Get this wrong and you'll either have walls you can't clean or walls that highlight every trowel mark.

The decision is simpler than that table makes it look. For most rooms in a new extension: matt on ceilings, matt on bedroom and living room walls, and either soft sheen or a durable matt in the kitchen and hallway. Silk is the traditional choice for kitchens and hallways, but a durable matt gives you the same wipeability without the reflective sheen that shows up plaster imperfections.

Trade paint vs retail paint

Walk into B&Q and pick up a 5L tin of Dulux Walls & Ceilings Matt. Then go to Screwfix and pick up a 5L tin of Dulux Trade Supermatt. The trade tin costs a few pounds more. But the trade tin contains more titanium dioxide (the white pigment that provides opacity), better thickeners for smoother flow, and higher resin content for better adhesion.

What does that mean in practice? The trade paint covers in two coats where the retail version needs three. On a whole room, that third coat adds two to three hours of work plus an extra day of drying time. Professional decorators use trade paint not because of snobbery but because it's genuinely faster and cheaper per finished square metre.

Where to buy trade paint without a trade account: Screwfix, Toolstation, and Brewers all sell trade paint to anyone. You don't need a card. Prices at these outlets are typically 10-20% cheaper than B&Q or Wickes for the same brands.

The mist coat: non-negotiable on new plaster

If your extension has freshly plastered walls (and it will), you cannot apply emulsion directly to the plaster. New plaster is highly porous. Paint applied straight onto it gets sucked into the surface unevenly, doesn't bond properly, and peels off in sheets. The fix is a mist coat: a diluted coat of cheap matt emulsion that soaks into the plaster, seals the surface, and gives the topcoats something to grip.

When the plaster is ready

New plaster must be fully cured before you paint it. That means uniformly pale pink (for standard Thistle plaster), with no darker patches. In a heated, ventilated room this takes four to six weeks. In winter with no heating, it can take eight weeks or more. Test it: press a piece of masking tape firmly onto the plaster, leave it for an hour, then peel it off. If plaster dust or fragments come away with the tape, it's not ready.

How to mix and apply a mist coat

Use a cheap white matt emulsion. Not silk, not vinyl silk, not "one coat." Plain matt emulsion. Contract matt from Leyland or Armstead is ideal, around £17 for 10 litres.

Dilute it with clean water. The exact ratio depends on the brand:

• General rule for new plaster: 70% paint, 30% water (a 7:3 ratio)
• Dulux recommends: 75% paint, 25% water (3:1)
• Leyland recommends: 90% paint, 10% water
• Crown recommends: 85% paint, 15% water

When in doubt, check the tin. If the tin doesn't specify, go with 70:30. The diluted mix should be noticeably thinner than normal paint, almost milky. Apply it with a 9-inch medium-pile roller. It will look patchy and uneven. That's correct. It's not a finished coat. Let it dry for 24 hours before applying your first topcoat.

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How to work with emulsion paint

Tools you need

A 9-inch roller frame, a roller tray, and two to three roller sleeves. Medium pile (around 12mm nap) for smooth plaster. Long pile (18mm+) for textured surfaces like Artex. You also need a 2-inch angled brush for cutting in (painting the edges where the roller can't reach: corners, around light switches, along the ceiling line and skirting boards).

Buy decent roller sleeves. The cheap ones shed fibres into the paint and leave a stippled finish that looks amateur. Purdy or Hamilton roller sleeves cost a few pounds more and the difference is visible.

The right technique

Paint the room in this order: ceiling first, then walls, then woodwork (if you're doing it). Work in daylight or with good temporary lighting. Dim conditions hide missed patches that become obvious once the furniture goes in.

Cutting in: Load the angled brush, wipe excess on the tin edge, and paint a band about 50mm wide along every edge: ceiling line, corners, around sockets, around door frames. Do one wall at a time, then immediately roll that wall while the cut-in band is still wet. If you cut in the whole room and then start rolling, the cut-in edges will have dried and you'll get a visible line (called "banding" or "picture framing") where the brush marks meet the roller texture.

Rolling: Load the roller by running it through the paint in the tray, then roll it back and forth on the tray ramp to distribute the paint evenly. Apply to the wall in a rough W or M shape, then fill in with even, parallel strokes. Overlap each stroke slightly. Don't press hard. Don't overload the roller. And keep a wet edge, meaning always roll back into paint that's still wet, never into paint that's started to dry.

Two coats minimum. Wait for the first coat to dry fully (check the tin, typically two to four hours) before applying the second. The second coat is what gives you even colour and full opacity.

One-coat paints: the reality

Marketing. Every community forum, every professional decorator, every experienced homeowner reaches the same conclusion: one-coat emulsion does not deliver a consistent, opaque finish with a roller in a single pass. You will see spots where the roller has overlapped, thin areas where it hasn't, and colour variation where the substrate shows through. The only reliable single-coat method is spray application, which most homeowners don't have access to.

Buy standard two-coat paint. It's cheaper per litre and gives a better result.

How much paint do you need

The formula is straightforward:

1. Measure the room perimeter (total length of all walls)
2. Multiply by the ceiling height to get total wall area
3. Subtract windows (roughly 1.5 m2 each) and doors (roughly 1.75 m2 each)
4. Multiply by the number of coats (two for emulsion)
5. Divide by the coverage rate on the tin

Worked example: a 4m x 5m room with 2.4m ceilings

• Perimeter: (4 + 5) x 2 = 18m
• Wall area: 18 x 2.4 = 43.2 m2
• Subtract one window (1.5 m2) and one door (1.75 m2) = 39.95 m2
• Two coats: 39.95 x 2 = 79.9 m2
• Coverage rate: 12 m2/L (use this as a safe planning figure for coloured emulsion)
• Paint needed: 79.9 / 12 = 6.7 litres
• Add 10% waste: 7.4 litres
• Buy: 2 x 5L tins (you'll have some left over for touch-ups, which you'll need)

For ceilings, calculate the floor area (4 x 5 = 20 m2), multiply by two coats (40 m2), divide by coverage rate (12 m2/L) = 3.3 litres. One 5L tin covers a ceiling this size with room to spare.

Cost and where to buy

Paint prices vary enormously by brand tier. The graph cost range is £20 – £37 per 5L for standard emulsion, but premium products go well beyond that.

Brand tiers

The price difference between buying Dulux at B&Q (around £36 for 5L) and at Screwfix (around £24 for the same product) is striking. Always check Screwfix and Toolstation before walking into a DIY shed. No trade card required.

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For a typical extension with one large room (say 25 m2 of floor area), you'll need roughly 3 x 5L tins for walls and 1 x 5L tin for the ceiling, assuming two coats of standard emulsion. At Crown Trade prices, that's around £130 for all the emulsion. At Farrow & Ball, the same room costs £320+. The walls don't know the difference.

Where to buy

• Screwfix and Toolstation - best prices on Dulux, Leyland, and Crown trade ranges. Click and collect same day.
• Brewers - the specialist decorating merchant. Widest range of trade brands including Johnstone's, Tikkurila, and Albany. Can colour-match Farrow & Ball into cheaper base paints. Staff actually know about paint.
• B&Q and Wickes - convenient for colour browsing and tester pots. Prices are typically 20-40% higher than Screwfix for branded paint. Own-brand ranges (Wickes Tough & Washable, GoodHome) are decent mid-range options at better value.
• Independent decorating merchants - often the cheapest for trade brands if you're buying in quantity.

Kitchen and bathroom emulsions

Specialist kitchen and bathroom emulsions contain additional fungicide to resist mould growth and have higher moisture resistance. Dulux Easycare Kitchen and Dulux Easycare Bathroom are the most common. They cost more per litre (typically £8 – £10/L vs £5 – £7/L for standard emulsion) and cover less (8-10 m2/L vs 12-14 m2/L).

Are they necessary? In a kitchen with a good extractor fan, a standard durable matt or soft sheen will be fine. In a bathroom with poor ventilation, the anti-mould formulation is worth the premium. Don't use them on ceilings unless the room has a specific moisture problem.

Alternatives

If emulsion paint isn't the right product for your application:

• Primer/sealer - for bare plaster (as a mist coat) or stained surfaces. Applied before emulsion, not instead of it. See the primer and sealer guide for when you need a dedicated primer vs a diluted emulsion mist coat.
• Masonry paint - for external walls. Emulsion is interior-only.
• Oil-based eggshell or satinwood - for woodwork (skirting boards, architraves, door frames). Not the same product as water-based emulsion eggshell despite the confusingly similar name.
• Lime wash or clay paint - for period properties with lime plaster. Do not apply modern emulsion to traditional lime plaster as it traps moisture and damages the substrate.

Where you'll need this

• Decoration - emulsion paint for all internal walls and ceilings, applied after plastering has fully cured

Common mistakes

Painting too soon after plastering. Four to six weeks is the minimum cure time for new plaster. Longer in cold or poorly ventilated rooms. The masking tape test (described above) is the only reliable way to check. Relying on a calendar alone will catch you out in winter.

Skipping the mist coat. Non-negotiable on new plaster. Use cheap matt emulsion diluted with water, not expensive paint, not vinyl silk, not "one coat." The mist coat exists to be absorbed into the plaster, not to look good.

Buying retail paint at B&Q prices when Screwfix sells the same product for 30% less. Check online prices before you drive anywhere. The identical Dulux product can vary by £12 per 5L tin depending on retailer.

Using standard matt in the kitchen hallway. Standard matt emulsion marks every time someone brushes against it with a bag or coat. A durable matt or soft sheen costs more per tin but you won't be touching up every three months.

Choosing silk because "it's wipeable" without realising it shows every plaster imperfection. Silk finish is brutally honest about the surface underneath. Unless your plasterer has delivered genuinely flat walls, silk will highlight every ripple and trowel mark. Durable matt gives you wipeability without the sheen.

Cutting in the whole room before rolling. Cut in one wall, roll it immediately while the edges are wet, then move to the next wall. Cutting in all four walls first guarantees visible banding where the dry brush edges meet the wet roller texture.

Not stirring the paint. Pigment settles. The paint at the top of the tin is a different consistency (and sometimes colour) from the paint at the bottom. Stir thoroughly before use and again periodically while painting. This is especially true for tinted colours.