Do Microcement Floors Crack?
Microcement floors can crack — but when they do, it’s almost always because of movement in the substrate beneath, not because microcement is inherently weak.
Understanding why cracks happen (and how to reduce the risk) is essential, especially if you’re installing a microcement floor yourself.
Why microcement floors crack
Microcement is a thin decorative finish, typically around 1–2mm thick. It doesn’t add structural strength to a floor. If the surface underneath moves, flexes, or expands, that movement can transfer through to the finish.
The most common causes of cracking are:
- Movement in screeds or concrete slabs
- Flexible or poorly fixed boarded floors
- Thermal movement (especially with underfloor heating)
- Existing cracks telegraphing through
- Applying microcement too thickly
Is cracking inevitable?
No — but it can’t be ruled out completely. Microcement systems are designed to tolerate minor movement better than traditional thick cement finishes, but they can’t overcome significant structural movement.
Most successful microcement floors rely on good preparation and sensible expectations, not the idea that cracks are “impossible”.
The role of reinforcement mesh
Reinforcement mesh is commonly used as part of a microcement floor system, usually embedded into a preparation layer such as a self-levelling compound.
Mesh helps to:
- Distribute stresses across the surface
- Reduce the chance of hairline cracking
- Limit crack propagation if movement occurs
Mesh doesn’t eliminate movement — it helps manage it.
Do you need expansion joints with microcement floors?
Microcement floors are seamless in appearance, but that doesn’t mean movement can be ignored. Existing expansion joints, day joints, or changes in substrate should usually be respected and carried through the system.
Ignoring movement joints is a common cause of cracking.
Cracking and underfloor heating
Underfloor heating introduces repeated thermal expansion and contraction. Microcement can work very well with underfloor heating when installed correctly, but heating cycles, mesh reinforcement, and controlled temperature changes are essential.
Sudden temperature changes significantly increase the risk of cracking.
What DIYers can do to reduce cracking risk
- Ensure the substrate is flat and structurally sound
- Repair or stabilise existing cracks before starting
- Use reinforcement mesh where appropriate
- Apply microcement in thin, controlled layers
- Respect drying and curing times
- Follow heating protocols if underfloor heating is present
Microcement cracking FAQs
Do microcement floors crack easily?
No — not when installed over a stable substrate and applied correctly. Most cracking issues are caused by movement beneath the microcement rather than the finish itself.
Will reinforcement mesh stop microcement cracking?
Mesh helps reduce the risk and spread of cracking, but it can’t eliminate movement in the substrate. It’s a risk-management tool, not a guarantee.
Can existing cracks show through microcement?
Yes. If existing cracks aren’t properly addressed, they can telegraph through the finish over time.
Do microcement floors crack with underfloor heating?
They can if heating protocols aren’t followed. Controlled heating cycles and gradual temperature changes are essential to reduce risk.
Is cracking covered by warranty?
Cracking caused by substrate movement or installation issues is typically not covered, as it’s outside the control of the microcement material itself.
