Microcement guide

Microcement problems, and how to avoid them

Most microcement problems start with what’s underneath, or the wrong system for the room, not the finish itself. Here’s what causes them, and how to get it right first time.

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The short answer

The most common microcement problems are cracks, poor bond, damp and staining in wet areas. Almost all of them come down to preparation or choosing the wrong system. With a sound background and the right system for the room, microcement is hard wearing and long lasting.

Our own proof is the Politura microcement floor at SEVENSTORE in Liverpool, a busy clothing shop. It was laid in 2020 and has needed nothing beyond daily cleaning since: no re-seal and no repairs.

At a glance

Cracks: Movement underneath
Poor bond: A weak or dusty background
Damp: Moisture coming up from below
Wet areas: The wrong system

Common microcement problems, and how to avoid them

Problem	What causes it	How to avoid it
Cracks	Cracks or movement in what’s underneath showing through	Repair cracks and stop any movement first, tape board joints and carry movement joints through the finish
Poor bond	A weak, dusty or contaminated background	Make sure it’s rigid, dry, clean and keyed. Grind and repair before priming
Damp	Moisture coming up through the slab, which can push a coating off	Measure it, never guess. Use the damp primer for your system: EP72 for Politura microcement, Erre-Block One for ErreLAB
Staining in showers	A mineral or acrylic finish, which relies on its sealer for water resistance	Use an ErreLAB resin system, which is waterproof at every layer
Grout lines showing	Tile joints not filled, or no reinforcement in the base coat	Fill and level the joints, and build carbon fibre or mesh into the base coat
Marks and patchy areas	Product that wasn’t fully mixed, or stopping mid-pass	Mix each container fully, including the edges and base, and keep a wet edge
Dirt in the finish	Dust and draughts while it’s being applied	Keep windows and doors shut while it’s being applied and while it dries

Not sure about your floor or wall? Call our technical team on 01472 240 340 before you start.

Does microcement crack?

The products themselves are designed not to crack. But microcement is a thin surface coating, about 2–3 mm, so cracks or movement in what’s underneath can show through. That’s why cracking is nearly always a background problem rather than a product problem.

To stop it happening, repair any cracks and fix the cause of any movement before you start, tape over board joints, and carry movement joints through the finish. Run new underfloor heating for at least 28 days, then switch it off before work begins.

Politura microcement doesn’t need a reinforcing mesh. ErreLAB has an optional carbon fibre reinforcement, which we recommend over tiles.

Already got cracks? It depends on the crack, what caused it and whether it’s still moving, so call us on 01472 240 340 and we’ll help you work it out.

What to get right

A few things make all the difference.

The backgroundRigid, solid, level, dry and keyed. Adhesion is never better than what’s underneath.

The right systemErreLAB for showers and wet rooms. Politura microcement and ErreFast for use away from direct water.

The right primerIt depends on what’s underneath, so choose the primer made for that background.

The stated coverageA thicker coat isn’t a better one. It can cause problems at later stages.

Time between coatsAllow the full time between coats. Rushing causes problems later.

A skilled handIt’s applied by hand. We can put you in touch with people in your area who apply our products, and we train applicators too.

Questions about microcement problems

What are the most common microcement problems?

Cracks from movement underneath, poor bond on a weak or dusty background, damp coming up through the slab, and staining where the wrong system is used in a shower. All of them can be avoided with the right preparation and system. See our substrate preparation guide.

Does microcement crack easily?

No. The products are designed not to crack, but cracks or movement in what’s underneath can show through. Repair cracks and carry movement joints through the finish.

Can microcement go over a cracked floor?

Repair the cracks and stop any movement first. For a badly cracked slab, talk to our technical team on 01472 240 340 before starting.

Why has my microcement cracked?

Usually because something underneath has moved. It depends on the crack and whether it’s still moving, so call us on 01472 240 340 and we’ll help you work it out.

How long does microcement last?

Many years when it’s prepared, applied and sealed properly. Our Politura microcement floor at SEVENSTORE in Liverpool was laid in 2020 and has had no re-seal and no repairs since.

Can microcement go in a shower?

Yes, with an ErreLAB resin system, which is waterproof at every layer. See is microcement waterproof?

Can plasterers apply microcement?

Yes. It suits people with trowel or finishing experience, such as plasterers, tilers, decorators and flooring contractors. Our training courses are hands-on.

More microcement FAQs →