Microcement glossary: 30 terms explained

Planning a microcement project introduces a lot of new vocabulary. This microcement glossary explains 30 terms you are likely to hear, from the first site assessment to the final coat of sealer, in plain English and grouped by topic.

The definitions are general. The right system, preparation and process for your surfaces are always confirmed on site.

Materials and system

Microcement

A polymer-modified, cement-based coating for floors, walls, ceilings and furniture, indoors and outdoors. It combines cement, water-based resins, additives and mineral pigments and is applied by hand in thin layers to a total of around 2–3 mm, creating a continuous surface without the joints of tiles or boards. Our guide to what microcement is covers the basics in more depth.

Two-component system

A microcement supplied as two separate parts that are combined shortly before use, rather than as a single ready-mixed product. Mixing them in the right proportions gives the coating its workability, adhesion and strength. Luxury Concrete's base, floor and wall microcements belong to a two-component system.

Part A and Part B

The two parts of a two-component microcement. Part A is the cement-based component and Part B is the resin it is mixed with. In the Luxury Concrete range, Microcement Resin is the Part B for the two-component system.

Pigments

The colouring agents in microcement. Mineral pigments are part of the basic blend and give each colour in a collection its tone. Because the material is hand-trowelled, colour can read with subtle variation across a surface.

Primer

A preparatory coat applied to the substrate before any microcement. It supports adhesion, seals the surface and helps prevent moisture problems, and it is left to dry before application continues.

Base coat

The first microcement layers, applied over the primer to build a strong, seamless foundation. The standard sequence uses two base layers, each left to dry, followed by sanding to remove irregularities.

Finish coat

The finer microcement layers that form the visible surface. Two finishing layers are applied over the sanded base, with drying and sanding between them, and they determine much of the final colour and texture before sealing.

Surfaces and substrates

Substrate

The existing surface that microcement is applied to. Cement mortar, self-levelling mortar, terrazzo, marble, tile, plaster, plasterboard and metal can all serve as substrates, while natural wood and substrates made from pieces that may expand at different rates are not advised.

Substrate humidity

The moisture content of the substrate, which must be below 5% before microcement is applied. New screeds, freshly rendered walls and areas affected by leaks can hold moisture and may need more drying time or remediation first.

Cement mortar

A mix of cement, sand and water used to render walls or lay floors. Once it has set and is stable and dry enough, cement mortar is a suitable substrate for microcement.

Self-levelling mortar

A flowable cement-based mortar that spreads out to form a flat, level surface, often used to correct uneven floors. Once it has set and is stable, it is a suitable substrate.

Screed

A cement-based layer laid over a slab to create a level floor and, in heated floors, to cover the heating pipes. With underfloor heating, an expansion joint is required between the screed and vertical walls so the screed can expand.

Terrazzo

A composite surface made from chips of stone or glass set in a binder and polished smooth. Stable, well-bonded terrazzo is a suitable substrate, so a dated terrazzo floor can be refinished without removal.

Plasterboard

Sheets of gypsum plaster faced with paper, widely used for internal walls and ceilings. Plasterboard is a suitable substrate for microcement when it is stable, securely fixed and properly prepared.

Over-tile application

Applying microcement directly over existing tiles instead of removing them. Its strong adhesion makes this possible when the tiles are firmly adhered and stable, avoiding the time and mess of demolition. See our guide to microcement over tiles.

Expansion joint

A deliberate gap that allows part of a building to expand and contract without cracking. Heated floors require an expansion joint between the screed and the vertical walls. Polished concrete often needs expansion joints, while microcement creates a continuous surface; where the substrate beneath has movement joints of its own, how they are handled is assessed for each project.

Underfloor heating

A heating system installed within the floor. Microcement can be applied over it with specific protocols, including turning the heating on at least four weeks after laying the base layer, changing temperatures gradually and switching it off at least 48 hours before installation. See microcement and underfloor heating.

Application

Surface preparation

The first step of application: cleaning and preparing the substrate so it is free from dust, grease, old paint or anything else that could prevent an effective bond. Over tiles, it includes checking that every tile is firmly adhered and stable.

Trowel and hand-trowelled

A trowel is a flat-bladed hand tool used to spread and compress microcement. Hand-trowelled means each layer is applied and worked by hand, which gives the finish its subtle movement and makes every surface slightly different.

Scratch coat

Another name for the first base layer. It is trowelled onto the primed substrate and left to dry before the second base coat goes on.

Sanding

Abrading a dry layer to remove irregularities. The base layers are sanded before finishing, and the finishing layers are sanded between coats, which helps create a smooth final surface.

Curing

The period after application in which microcement continues to harden and gain full strength, over several weeks. Take care with the surface during the first week after completion while it develops its full hardness and resistance.

Finish and protection

Sealer

A protective coating applied over the dry finish coats. It protects the surface from wear, water and stains and enhances the colour, and several coats may be required. The sealer is what makes microcement water-resistant, and it needs periodic maintenance depending on traffic and use.

Polishing

The final step of application, in which the sealed surface is polished for a smooth, flawless finish. It follows sealing rather than replacing it.

Sheen: matte, satin and gloss

How much light a surface reflects. Microcement can range from matte to glossy: matte is soft and low-reflection, satin has a gentle sheen and gloss reflects the most light and deepens colour. The sealer and final polish both influence the result.

Water-resistant vs waterproof

Microcement itself is not waterproof. When a proper sealer is applied as the finishing layer it becomes water-resistant, which allows it to be used in bathrooms, kitchens and other areas exposed to water or humidity. It is a finish rather than a waterproofing membrane, so wet-area waterproofing is confirmed separately.

Seamless

Continuous, without the joints or grout lines of tiles or boards. A seamless microcement surface can run across floors, walls and furniture, leaving fewer places for grime to collect and helping a space feel larger and more unified.

Design and appearance

Natural variation and clouding

The soft tonal shifts and movement in a hand-trowelled surface. Clouding is a normal part of the finish rather than a defect, and it means no two surfaces are exactly alike.

Oxid metal finishes

Metallic-effect finishes from the Oxid Metal collection: Brass, Bronze, Copper and Heavy Iron, each offered with and without an oxidant. The oxidant versions have an aged, patinated look, from blue-green verdigris to rust-toned iron. Browse them on our colours and textures page.

Feature wall

A single wall finished to stand out from the rest of a room through colour, texture or both. Microcement suits feature walls because it adds depth while keeping the surface continuous; see microcement feature walls.

The microcement application steps at a glance

Many of these terms describe stages of the same sequence. A typical microcement application follows eight steps.

1. Surface preparation
2. Primer application
3. First base layer, or scratch coat
4. Second base layer
5. Sanding
6. Two finishing layers
7. Sealing
8. Polishing

Our process page explains each stage in more detail. If a term you have heard is not listed here, contact us and we will explain it.