The difference between matt and silk paint in 2026

Matt and silk are the same emulsion doing two different things with light. Matt reads at 10 gloss units or below and scatters light in every direction, so it flattens bad plaster. Silk sits in the mid-sheen band and reflects light back at you, so it picks out every ridge, filler edge and roller lap. Everything else follows from that one difference.

The part the buying guides miss: a modern durable matt now reaches Class 1 wet-scrub under BS EN 13300, tested to 10,000 scrubs. It clears the same published class as a standard vinyl silk while keeping a flat, flaw-hiding finish. Silk is no longer the automatic answer for a wall that gets wiped.

Two more facts worth having before you open a tin. Matt over silk crazes if you do not key or seal the wall first. And silk peeling off a wall is a separate failure with a separate cause, which means a separate fix.

How is the difference measured?

BS EN 13300 is the European classification standard for interior wall and ceiling coatings. It sets gloss by specular reflectance, read on a glossmeter at 60 degrees under EN ISO 2813, and where the 60 degree reading falls below 10 gloss units the coating is re-read at 85 degrees to classify it.

It does not publish the six-way matt, silk, satin, gloss split a decorator thinks in, and the numeric class limits sit inside the paywalled standard, so they are not reproduced here.

What decorators work to is a maker’s own sheen scale. Tikkurila UK publish theirs in gloss units:

Source: Tikkurila UK sheen level guide. This is one manufacturer's scale, not the standard's, and the band edges vary between makers.

One honest caveat on top of that. UK trade data sheets do not print a gloss-unit figure per product. You will not find a number on a Vinyl Silk sheet to compare against a Vinyl Matt sheet. Treat the bands as the map, not as a spec you can look up.

Why does matt hide flaws and silk find them?

A matt film carries a high pigment and extender load. That leaves a rough surface which scatters incoming light in all directions, so the wall returns roughly the same brightness from every angle. The shadows thrown by bumps, filler edges and uneven plaster are not reinforced, and the flaw flattens out.

A silk film carries more binder and a smoother surface, so it reflects more like a mirror: bright at the complementary angle, dark elsewhere. Under raking light from a window or a stairwell rooflight, every ridge and hollow throws a light and dark pair that the eye reads as a defect.

UK trade sources put it the same way. Silk shows a poorly filled crack, a ridge left by a previous coat, or slightly uneven plasterwork far more clearly than matt, and grazing light makes it worse. If the walls are old, patched, or have been papered and stripped, sheen is working against you before you start.

”Matt” is three different paints

Half the arguments about matt happen because two people are talking about different tins.

Contract matt has no guts to it, which is the point: it is meant to be permeable so it can go over plaster that is still giving up moisture. It is a first coat on a new wall, not a finish for a lived-in room. New plaster is its own job with its own ratios, covered in the mist coat guide.

Which one survives being washed?

BS EN 13300 runs five wet-scrub classes, Class 1 highest to Class 5 lowest, measured as film thickness lost under EN ISO 11998.

Source: BS EN 13300, test method BS EN ISO 11998.

Where the named UK trade paints land:

Sources: manufacturer technical data sheets and product guides, accessed 24 Aug 2026.

Two things to read out of that. First, no maker checked here publishes a wet-scrub class for a standard vinyl matt at all. The published classes belong to the silks and to the durable matts, which tells you where each maker thinks the washing happens.

Second, Class 1 is a floor, not a ranking. A Class 1 silk and a Class 1 durable matt clear the same bar and the standard does not separate them above it. That is why makers reach for numbers of their own. Dulux puts Diamond Matt at 10,000 scrub cycles, five times the rate it says the highest durability rating requires, and calls it ten times tougher than its own Vinyl Silk and Vinyl Matt. Both are the maker’s comparisons rather than standard-defined, and should be read that way.

What holds either way is the choice that has moved, and it moved recently: Dulux reformulated Diamond Matt in 2023. If you wanted a wall you could wipe, silk used to be the only published route to it. It is not any more, and a durable matt gets you there with none of the sheen.

Which finish goes on which wall?

Match the scrub class to how much wear the wall takes, and match the sheen to the condition the wall is in. Those are two separate decisions and both matter.

That kitchen and bathroom line is worth saying to a customer out loud, because it is the maker’s own written limitation, not a decorator’s preference. If someone asks for silk in a steamy bathroom on the grounds that it wipes clean, the sheet says use a moisture-resistant eggshell or a bathroom-grade durable matt.

Ceilings are almost always matt: a flat finish kills glare from overhead light and hides plaster undulation, where silk shows every trowel line, and Toolstation’s buying guidance says the same. Ceilings are their own job and get their own guide.

What happens if you paint matt over silk?

It crazes. Decorators call it mud cracking, or the crazy paving effect, and it shows up within hours.

The mechanism is keying, not adhesion in general. A cured silk film is dense, smooth and low-porosity. A water-based matt laid over it cannot soak in and has nothing mechanical to grip. As the matt loses water and shrinks on drying, it pulls against itself instead of against the wall, draws together and cracks open across the face.

Retailer and trade guidance agree on the fix, and it is the same one either way: because silk leaves a non-porous surface, matt over the top needs proper preparation, meaning sanding and priming, before it will bond.

So the honest answer to “can you paint matt over silk” is yes, and never straight over the top.

Why does silk peel off the wall?

This is a different failure, running in the opposite direction, and it gets confused with the one above.

Crazing is the new coat failing to grip the silk. Peeling is the silk itself failing to grip whatever sits beneath it. Three common causes:

1. The wrong primer, or none. Trade diagnosis is that peeling silk usually comes down to an incorrect primer, or the silk going over a chalky matt. It is an adhesion problem below the film, not a problem with the silk.
2. A chalky, under-bound base. On drylined board, the plasterboard can drink too much of the binder out of the coat beneath, leaving a powdery surface. The silk sits on dust and lifts off in sheets.
3. Trapped moisture. A standard vinyl silk forms a relatively dense, non-breathable film. Where moisture is evaporating out of the wall it reaches the back of that film and cannot pass through it. The pressure of the trapped vapour pushes the coating off the wall.

Same symptom, paint coming off in your hand, opposite direction of failure. Diagnose which one you have before you decide what to buy, because a bonding primer fixes the first two and does nothing for the third.

How do you prepare a wall that is already in silk?

Two accepted routes over sound silk. Key it, or seal it.

Key it. Rub down with fine abrasive to break the sheen, then rinse. The trade data sheet wording for previously sheened surfaces is to rub down with fine waterproof abrasive paper and rinse thoroughly. General prep from the same sheets: the surface must be sound, clean and dry, all loose and defective paint removed, and any dirt, grease or powdery residue washed off and rinsed with clean water before it dries.

Seal it. Sand lightly, then a high-adhesion primer or sealer that bonds to sheen, left to cure properly before the matt goes on. In UK trade practice that means Zinsser Bullseye 123, or Zinsser B-I-N where the wall is doubtful. This is the more reliable route and the one most decorators default to on a wall they did not paint themselves.

On a wall that has been painted many times, the risk moves. The question is no longer only whether your top coat will key to the silk. It is whether the whole stack underneath is soundly bound. On repeatedly painted lining paper or drylined board, sanding can drag the old layers off with it. So test adhesion first, strip back anything that is not holding, and favour a bonding primer over sanding it back.

Take the extra half day. Crazing is not a touch-up job, it is a strip-and-start-again job, and it happens on your time.

Does silk cost you more time than matt on the same wall?

No source puts a number on it, so nobody should quote you one, including this page. What is well documented is where the extra time goes.

Silk shows every brush and roller mark, and it flashes and picture-frames, which UK trade sources describe as commonplace and noticeable, worst in large rooms with a lot of light. It needs a wet edge kept moving and laying off in one direction. It wants a skilled hand to come out clean. Matt forgives all of that, and matt touches up; silk does not touch up, it patches and shows, and then you are cutting the whole wall in again.

Price the care, not the tin. The material difference between a matt and a silk on the same room is small. The difference in how long it takes to get a clean finish, and in what happens if you get a callback, is not. That is a pricing decision rather than a paint decision, and it is covered in the guide to pricing decorating jobs.

Coverage and recoat times, side by side

Sources: manufacturer technical data sheets, checked 24 Aug 2026.

Two things to take from that table. First, “up to” means smooth and sound. New plaster, porous board and deep colours cut real coverage, which is why contract matt on fresh plaster can fall to 12–14 m²/L. On paper matt spreads further than silk, 17 against 16 m²/L for the Dulux pair, but the real cost driver is the number of coats and how much cutting-in the room needs, not the spread rate.

Second, standard matt and standard silk from the same maker share the same 2–4 hour recoat window, so neither wins on scheduling. Durable matt is slower at 4–6 hours. If you are planning two coats in a day, that is the number that decides it.