Floor systems
Microcement Floors: Substrate, Build-Up And Wear
A microcement floor is a system, not a product. Primer, reinforcement, base coats, finish coats and sealer each do a specific job, and the floor performs at the level of its weakest layer.
The layers and what each one does
Removing or reducing any of these is where cheap quotes come from. Skipping mesh saves half a day and costs a floor. Reducing a three-coat sealer schedule to two saves materials and roughly halves the practical life of the surface in a busy household.
- Primer
- Controls absorbency and creates the bond to the substrate
- Reinforcing mesh
- Distributes stress across joints and substrate changes
- Base coats
- Build the body, level minor variation, take the mesh
- Finish coats
- Deliver colour, texture and the trowel character
- Sealer schedule
- Provides stain and wear resistance at the surface
Substrates, ranked by how well they behave
Power-floated concrete and sand-cement screed are the ideal substrates: stable, predictable and easy to prime. Anhydrite screeds work perfectly well once the laitance has been mechanically removed and the correct primer is used, but that preparation is mandatory rather than optional.
Timber floors are the ones that need real judgement. A rigid, well-fixed board deck with minimal deflection can take a floor system with appropriate reinforcement. A springy first floor with creaking joists cannot, and no primer will change that. Deflection is assessed before anything is quoted.
- Power-floated concrete: straightforward
- Sand-cement screed: straightforward once cured and dry
- Anhydrite screed: fine after mechanical removal of laitance and correct priming
- Existing tiles: viable when fully bonded, joints filled and meshed
- Timber decks: only after a deflection and fixing assessment
Moisture is the failure most people never see coming
New concrete keeps releasing moisture for a long time after it looks and feels dry. Applying a floor system before residual moisture has come down to a workable level traps that water beneath a relatively impermeable finish, and the pressure eventually shows as blistering or debonding. A hygrometer or calcium chloride test gives you an actual number instead of an opinion.
Older ground floors present the other version of the problem: a missing or breached damp-proof membrane. That has to be resolved with a surface damp-proof membrane before the finish, not diagnosed afterwards when the surface begins to lift in one corner.
Ask for the moisture reading and the date it was taken. A floor system laid over an untested slab is a gamble with somebody else's money.
How the floor behaves over years of use
In residential use a sealed microcement floor takes footfall, furniture and daily cleaning without difficulty. Grit is the enemy, because grit under a shoe is an abrasive and the sealer film is what wears. Doormats at external doors do more for the longevity of the surface than any product on a shelf.
Expect the sealer to be a maintenance item over a long period rather than a permanent layer. Refreshing it in a high-traffic route is straightforward and restores both the appearance and the protection. Handing that information over at completion, ideally with a written aftercare note, avoids a client interpreting normal wear as a defect.
Floor specification queries
The questions to ask any floor quote
Which primer, how much mesh, how many finish coats, how many sealer coats, and what was the moisture reading. Any quote that answers those five clearly is worth comparing. We are happy to price a floor on exactly that basis.