Prep for Floor Tiles
The following prep & conditions apply to preparing floor tiles for microcement:
Well Consolidated and Flat
Make sure tiles aren’t drummy or loose. Take out any which are & relay them. The surface must be completely flat.
As with all surfaces, microcement will follow the contours of the substrate it is going onto. If a lot of the tiles are loose or uneven, it may be better to remove them. If they are fixed firmly in place but uneven, you could consider self levelling over them to flatten them off – follow manufacturer’s recommendations for applying the leveller over tiles.
Clean Tiles & Give them a Key
The tiles must be clean and free from dirt, dust and grease. Grout lines must also be clean and free from moisture. Ideally, run an abrasive sander over the surface to ensure the primer achieves good adhesion with the surface.
There are 2 different options for filling the grout lines:
Option 1: Fill the Grout Lines with MicroDur Base
This is the more basic process.
Fill the grout lines with MicroDur Base so that they are flush with the tiles.
IMPORTANT: Leave until dry, minimum 24 hours. If the MicroDur Base isn’t completely dry, the grout lines may ghost through the microcement and be visible in the finish.
Once the MicroDur Base is dry, cut mesh and lay it over the whole area, not overlapped, flip the mesh so it curls towards the surface and apply Primer TAC over it with a medium pile roller. The Primer TAC will hold the mesh in place. Primer TAC will keep it’s TAC so for floors, you will need spiked shoes to walk on it.
Option 2: Fill the Grout Lines with Epoxy, Mesh & Sand Blind
This is the more advanced process. The best way to minimise the chance of movement transferring through to the surface is to apply Epoxy, Mesh & Sand Blind over the entire floor.
The epoxy will also fill the grout lines to make the floor flat. Many installers choose to use it on all floors as it ensures the floor dries at a uniform rate, helps to prevents stains in the substrate ghosting through to the microcement and strengthens the base. Use a trowel to apply an even coat of Epoxy over the sub-floor and mesh. You’ll need to ensure you have completely filled the grout lines in the sub-floor and also completely covered the mesh.
Whilst the Epoxy is still wet, spread the quartz sand across the surface. You can scatter it by hand, starting at the entrance to the room and walking on the sand into the room. Or by walking on the Epoxy with spiked shoes. The following day, sand any high spots and hoover up all the loose sand.
You will need to prime the surface with Primer 100, you can apply a neat coat directly onto the sand. The Primer is applied with a medium pile roller.