What Microcement Actually Is, And What It Is Not

The composition, in plain terms

Microcement is a polymer-modified cementitious coating. Cement and graded fine aggregates provide the body, an acrylic or styrene-acrylic polymer provides the flexibility and adhesion, and mineral pigment provides the colour. It arrives as a powder and a liquid component that are mixed on site in a fixed ratio, then trowelled on in coats measured in fractions of a millimetre.

That polymer content is the difference between microcement and a sand and cement render. Render is rigid and cracks when the thing beneath it moves. Microcement flexes with small substrate movement, which is precisely why it can be laid at two to three millimetres over an existing floor without splitting the first time the building shifts.

Thickness changes everything about the decision

A full microcement build-up, primer through to sealer, typically finishes between two and three millimetres. That figure is why it exists commercially. It means no substantial loss of ceiling height, no doors to be trimmed, no thresholds to be redesigned and no structural loading calculation for an upper floor. On a refurbishment where every millimetre is spoken for, that is often the deciding factor rather than the aesthetic.

It also sets the limitation honestly. At that thickness the material has no independent strength. It borrows all of its structural behaviour from whatever it is bonded to. A sound, dry, stable substrate produces a floor that lasts. A hollow tile, a moving board or a damp screed will telegraph through, and no amount of skill in the trowelling will hide it.

Typical finished depth

2 to 3 mm including primer and sealer coats

Form

Two-part powder and liquid, mixed on site

Joins

None within a continuous area

Colour

Pigmented through the material, not applied on top

Where the material earns its place

The strongest arguments for microcement are continuity and adaptability. It runs across a floor, up a step, around a shower former and onto a wall without a single grout line or trim. It takes curves that a rigid sheet material cannot. It goes over an existing surface rather than into a skip, which shortens programmes and reduces waste on occupied refurbishments.

For designers the appeal is usually tonal rather than technical. Because it is trowelled by hand, the surface holds a subtle variation in depth that a printed or extruded product cannot replicate. Two installers working the same colour will produce visibly different surfaces, which is a feature in a private house and something to control tightly on a multi-unit development.

• Refurbishments where floor build-up height is fixed
• Wet rooms and shower enclosures where grout lines are unwanted
• Curved, stepped or sculptural forms
• Large open-plan areas that would otherwise need expansion detailing
• Interiors where a single tone needs to carry across several surface types

Where it is the wrong specification

Microcement is not a repair material. Laying it over a substrate with an unresolved damp problem, a live crack or a failing adhesive bed simply relocates the failure to a more expensive surface. Nor is it a fix for a floor that deflects underfoot, and timber upper floors need assessing properly before anyone talks about colour.

It is also not the cheapest way to make a surface look calm. Where budget is the primary driver and the substrate is already sound and flat, large-format porcelain will usually cost less. Specify microcement because you want the continuity and the height saving, not because you are hoping it will be a shortcut.

If a surveyor cannot tell you what the substrate is and what condition it is in, that question needs answering before a finish is chosen, not after.