These two get compared constantly and they should not really be alternatives. They are mineral finishes that look superficially similar in a photograph and do almost entirely different jobs. Choosing between them is usually settled by one question - does water land on it - and everything else is preference.
The short version
| Venetian plaster | Microcement | |
|---|---|---|
| Binder | Slaked lime | Polymer-modified cement |
| Thickness | Under 1 mm | 2-3 mm |
| Floors | No | Yes |
| Wet zones | Above splash height only | Yes, over a sealed membrane |
| Breathable | Fully vapour-open | No - sealed system |
| Period solid walls | Ideal | Avoid |
| Character | Depth, movement, light | Even, matt, concrete-like |
| Repair | Blended in place | Blended in place |
| Cure | Carbonation, months | Chemical, days |
They are made of different things
Venetian plaster is slaked lime carrying graded marble dust. It cures by carbonation - pulling carbon dioxide out of the air and hardening slowly back towards limestone over months. It stays open to water vapour for the life of the wall.
Microcement is cement modified with polymers and resins, applied over a primer and mesh and then sealed with a polyurethane. It cures chemically in days and once sealed, it is a closed system. Nothing passes through it in either direction.
That single difference - vapour-open versus sealed - decides most of the specification.
Where water is involved
Microcement, without much argument. It is the reason it exists: a continuous 2-3 mm surface with no joints and no grout, laid over a waterproofing membrane, so a shower enclosure, floor, bench and niche are one unbroken plane. Wet rooms are its strongest case.
Venetian plaster is fine in a bathroom above splash height and genuinely good there - lime is alkaline and mould does not like it. But it is not a wet-zone material and anyone offering it as one is either using a Tadelakt-family system and calling it something else, or is going to disappoint you.
Where the floor is involved
Microcement again and this is not a close call. Venetian plaster is under a millimetre thick and has no abrasion resistance worth discussing - it is a wall and ceiling finish. Microcement floors take a wear-rated seal and a mesh reinforcement layer and they work over screed, tile or timber and across underfloor heating.
Where the building is old
Here it flips completely. A solid wall built before about 1919 has no cavity and no damp-proof course and it manages water by absorbing and releasing it. Seal it with a polymer-modified cement and a polyurethane and the moisture has nowhere to go - it goes sideways and upwards instead and comes back as damp somewhere less convenient.
On solid walls, listed interiors and period property, lime finishes are correct and microcement is a mistake. That is a building-physics argument, not a taste one.
Where it is a matter of taste
On a dry internal wall in a modern building, both work and the decision is about what you want the room to feel like.
- Venetian plaster and Marmorino have depth. Light enters the upper layers, scatters off the marble and comes back out, so the surface changes through the day and shifts as you move past it. It reads as handmade, because it is - no two walls are identical.
- Microcement is quieter and more even. Its character is a soft cloud movement rather than depth and the reference points are concrete and stone rather than polished marble. It suits a contemporary interior where the finish should recede.
Put crudely: Venetian plaster is a wall you look at, microcement is a wall you stop noticing. Both are legitimate ambitions.
Thickness and why it matters more than it sounds
Under a millimetre versus two to three does not sound like much, but it changes what each can be applied over. Microcement's 2-3 mm is enough to go over existing tile without lifting it, which is often the whole commercial case for it on a refurbishment. Venetian plaster has no such capacity - it needs a properly prepared, flat substrate and cannot hide anything.
Neither can bridge movement. Both need whatever is underneath to be stable and a cracking substrate will come through either one.
Cost
They overlap enough that price rarely decides it. A four-coat honed Marmorino and a wall in microcement land in similar territory; a seven-coat burnished stucco is considerably more and a full sealed wet room in microcement is more again because of the waterproofing work underneath. Our costs page has the ranges and the variables.
Using both
The most satisfying projects we do frequently use both and this is worth saying because clients often assume they have to pick a side. A microcement floor running through an open-plan ground floor and Marmorino on the chimney breast in the same room. A sealed microcement shower enclosure and lime plaster on the dry walls of the same bathroom. Each material doing the job it is actually good at.
How to decide in thirty seconds
- Floor, shower, wet room or worktop → microcement.
- Solid wall, period property, listed interior → lime.
- Dry wall, modern building, want depth and light → Venetian plaster or Marmorino.
- Dry wall, want it calm and recessive → microcement.
- Still unsure → ask for both on a sample panel and look at them in the actual room. It settles it in about a minute.
If you would like both panels made up, tell us the room and we will bring them.