Microcement on cement boards – step by step

When entering a construction site in an apartment or premises in which the microcement is to be made, the substrate must first be properly prepared. As the microcement is only a finishing layer and its thickness is about 2-3 mm, it often happens that the floor should be raised to the appropriate level. In this way, the final microcement floor will be aligned with the doorsills and other rooms’s floor where e.g. a floorboards or tiles are used.

Cement boards for microcement as an alternative to self-leveling screed

Self-leveling screeds are most often used to level the floor height. They are affordable and available. However, the main disadvantage of this solution is that they dry quite a long time. It is assumed that for every one millimeter of the thickness of a traditional self-leveling screed, it is necessary to wait one day, e.g. if the screed is ten millimeters thick, it must dry for ten days. Only after this time, microcement application can most often be started. It should also be noted that self-leveling screeds often have a tendency to crack, which can directly contribute to scratching the top layer of microcement.

How to test and prepare the substrate for microcement

An alternative to this type of solution is the use of cement boards. Such boards consist of cellulose fibers bound with a cement binder. Their main advantage is that they have exceptionally good mechanical parameters: high stiffness and hardness – and therefore high resistance to deformation, as well as extraordinary strength. Some of them can also be used in wet areas and outdoors without fear of changing shape or physical parameters. In addition, they are non-flammable and come in many sizes and thicknesses, so it is easy to choose the right dimensions.

Microcement on cement boards – step by step

The first stage of works will be cleaning and priming the existing floor.

Microcement on cement boards - step 1

Then cut the boards to the dimensions of the room (it is good to number them so that they do not get mixed up). We mount them with board glue and wait for it to set (according to the manufacturer’s recommendations). The boards can be weighted on the edges so that they adhere well over the entire surface.

Microcement on cement boards - step 2
Microcement on cement boards - step 3
Microcement on cement boards - step 3
Microcement on cement boards - step 4

In order for the microcement to create a uniform surface without joints and cuts, the key issue is to ensure that no deformations or movements occur at the edges and joints between consecutive boards. Therefore, we recommend making oblique cuts in the joints of the panels, inserting steel bars into them and pouring epoxy resin into them. This treatment is aimed at stiffening the joints and the entire surface.

Microcement on cement boards - step 5
Microcement on cement boards - step 6

When the resin is dry, apply a primer coat of FESTFLOOR BASE and paste fiberglass mesh (also available as a kit). The substrate prepared in this way is protected against cracking and ready to receive microcement.

Microcement on cement boards - step 7

Then we apply the first layer of microcement, wait for it to dry, sand it, apply the second layer and sand it again. More information: Microcement application. Technical notes.

After curing, we apply appropriate protective agents as needed (primer, sealer, 3K Plus additive) – more: Which microcement varnish should I choose?).

Microcement on cement boards - step 9
Microcement on cement boards - step 10
Microcement on cement boards - step 11