Applying microcement: complete step-by-step guide
If you have landed on this article, it is because you have started researching how to apply microcement. So if microcement is your crush and it has completely stolen your heart, you are in the right place to discover our guide.
In it, we explain how to apply microcement step by step in a clear and simple way, with no frills: the most common installation mistakes and how to avoid them, as well as the essential tools for applying microcement.
Still getting your bearings? Start with what is microcement and come back here to apply it.
Applying microcement: quick summary of the steps
In short, whether you hire a professional or dare to apply it yourself, it is essential to follow the application process to the letter. Otherwise, the final result will not be what you expect.
- STEP 1: Preparing the surface
- STEP 2: Applying the primer and the mesh (if required)
- STEP 3: Applying the base or preparation microcement
- STEP 4: Applying the finishing microcement
- STEP 5: Applying the pore sealer (if required)
- STEP 6: Applying the varnish
How to apply microcement in 6 easy steps
Like an arrow flying straight to the bullseye or a spotlight shining on centre stage, we are not going to beat around the bush. Let's start by answering the key question: how to apply microcement.
The microcement application process is not made up of a fixed series of steps; it is a very dynamic procedure. That is why you will never find a universal application method valid for everything: although the microcement application process does have common elements, it varies depending on the factors involved. For example, the tools, the materials you will need and even the steps to follow will be determined by the type of microcement (cement-based, lime-based, epoxy-based, acrylic...) and also by its composition (single-component, two-component or ready-to-use microcement).
Once it is clear that the installation process varies depending on different elements or circumstances, keep reading to discover the general steps for applying microcement.
1: Preparing the work surface
For a correct microcement application, the substrate must be in optimal condition. Otherwise, problems will appear over time. The surface to be coated must be free of dust, grease and residues from other materials, with no cracks or damp. At the same time, we must make sure the surface is correctly levelled before applying microcement.
Getting the substrate right means it is level and there are no cracks, breaks or chips in the final finish. As microcement is a decorative coating with a minimum thickness of 3 mm, if the substrate is not prepared, any unevenness or imperfection would end up showing through, causing the microcement to crack.
In addition, if there are joints — typical of porcelain substrates or materials such as tiles — it is essential to fill them with a specific filler so they remain hidden from view. In this case, it must be left to dry completely, which usually takes around 24 hours.
2: Applying the primer and the mesh
Secondly, it is important to guarantee proper adhesion. That is, applying a primer that helps the existing surface material bond with the microcement. Here it is essential to choose the primer best suited to the surface you are going to coat: there are absorbent materials such as concrete or cement, and non-absorbent materials such as tiles or porcelain... And since each of them has specific characteristics and needs, you will need a different primer for each one.
There are different options and solutions on the market for each of them and, as they are not all the same, you will need to follow each manufacturer's instructions to the letter regarding application and drying time.
After applying the primer, in many cases it is essential to install a fiberglass mesh, especially on floors; on other occasions it will not be necessary. And what is the purpose of this element? To reinforce the strength and stability of the new microcement coating, preventing possible cracks and improving its performance.
Once the primer and the mesh (whenever it is necessary) have been applied, it is essential to follow the times set by the manufacturer and let everything dry thoroughly. In general, complete drying usually takes between 20 minutes and 2-3 hours depending on the product. Because when applying microcement, there is no room for rushing.
3: Applying the preparation microcement
Now that the substrate is prepared and in optimal condition to embrace the microcement, it is time to start with the real decoration. The first question to ask yourself is: what type of preparation microcement do you have? Because, as we explained when talking about types of microcement, the application process varies depending on its composition.
If you have a two-component system, you will have to mix it with a resin and then add the pigment to the product. If, on the other hand, you have a single-component system, you will need to add water instead of resin, plus the necessary dose of pigment. Now, if you choose to simplify the microcement application a little, with the ready-to-use system you will skip all of this: no need to add component B (neither resin nor water), and no need to become an alchemist to blend the pigment dose recommended by the manufacturer while praying to the stars not to get it wrong. Its name says it all: ready to use.
After making the mix (if necessary), it must be applied with a trowel, evenly and in very thin layers. Let it dry for the time prescribed by the manufacturer (drying times range from 4-6 h per coat up to 8 h) and, once dry, sand it to obtain a smooth surface. This step does not end with a single coat: generally, two will be needed. For each coat the process is the same: even application, letting it dry for the recommended time, and sanding.
In some systems, as is the case with Smartcret, the process becomes simpler because the microcement is applied directly with a polyamide roller and then smoothed over with the trowel.
4: Applying the finishing microcement
Now we focus on applying the finishing microcement, which is responsible for giving it the desired texture and colour. Just as with the preparation microcement — and as explained in the previous step — depending on the type of system you have chosen (two-component, single-component or ready-to-use), you may have to mix it with resin, water and add the pigment, or with nothing at all.
The installation process is the same as in the previous step. Once the mix is made (if applicable), it is applied with a trowel in thin coats. They are left to dry according to the manufacturer's instructions (from 4-6 h up to 8 h) and sanded (depending on the type of microcement you have chosen, the sandpaper grit will be between 80 and 220).
As in the previous step, Smartcret simplifies the finishing microcement application process: first roller and then trowel.
Generally, two coats are applied in this step and the process is the same for all of them, so be patient... and on with the microcement!
5: Applying the pore sealer
Depending on the microcement chosen, it will or will not be necessary to use a pore sealer before applying the varnish or sealing product. The pore sealer provides that first layer of protection and resistance to the material and acts as the bridge connecting the microcement with the varnish. This product is usually applied with a roller and, generally, in two coats.
6: Sealing the microcement
It is essential not to skip this step! Although it may seem that we have finished applying the microcement, that is not the case. It looks beautiful, but the last step is still missing: sealing it.
Using a protective sealer for microcement will keep the surface protected from daily wear, knocks, abrasion and liquids such as water, preventing stains. It will also intensify the final colour.
Depending on the type of sealing varnish, it may or may not need to be mixed with a component B. Just as with microcement, there are varnishes that are single-component and ready to use and therefore require no extras. Despite this difference, what they have in common is that they provide greater chemical and mechanical resistance.
This protection is applied with a roller in 2 or 3 coats (depending on the type of varnish) and left to dry completely. Generally, the drying time ranges from 4 h between coats up to 24 h and, on some occasions, sanding between them is necessary. Although, as you will have realised by now... you always have to follow the manufacturer's guidelines when it comes to times and processes.
How to apply microcement depending on the type of substrate
You have now seen the general steps for applying microcement on any surface. However, each substrate has technical particularities that must be taken into account during application. Working on a horizontal surface is not the same as working on a vertical one, nor is applying microcement in high-humidity environments the same as in dry rooms.
For this reason, it is essential to adapt the process depending on the type of substrate.
Applying microcement on walls
To apply microcement on walls, the technique must be adapted to vertical surfaces, bearing in mind that the trowel should be held at a 45° angle and moved in arching motions in different directions. If you are looking for the complete system for vertical surfaces, you have the microcement kits for walls.
Applying microcement in showers
A microcement shower becomes the undisputed star of a bathroom. And although the installation process is very simple, it differs slightly to account for the humidity of the room it is in. If you want to know how to apply microcement in a shower, you can read it in our article.
Applying microcement on stairs
A decorative technique on the rise is using microcement on stairs. To put it into practice, some application aspects must be taken into account, such as protecting the edges or leaving them with a slightly rounded finish.
Applying microcement on tables
A microcement table steals the gaze of every guest entering the living room. To apply microcement on tables, it is essential to follow the thin-layer application technique to achieve the desired result.
Applying microcement over tiles
It is possible to use microcement over tiles without having to remove or sand them beforehand. This makes it the perfect decorative coating for renovating your tiled surfaces while avoiding building work.
Is your project a floor? Complete it with the guide to microcement flooring.
What tools do you need to apply microcement?
Before starting the whole process, make sure you have everything you are going to need along the way. Below is a breakdown of the essential tools and accessories for applying microcement:
- Masking tape: to mark out the work surface and protect the areas you are not going to coat with microcement.
- Buckets and brushes: for mixing and applying the products.
- Rollers: for applying the primer and the sealer.
- Trowels: for applying the microcement.
- Spatulas: for working the corners and edges.
- Sandpaper: to leave the surface smooth between coats.
Other recommended, but not always essential, tools are:
- Gloves and masks: to protect yourself during application.
- Electric mixer or double-helix mixing paddle: depending on whether you mix it with water or with resin, one or the other will be recommended to blend it correctly.
- Electric sander and ceramic mesh discs: if the work surface is very large, their use may be advisable, although manual sanding is perfectly possible.
Most common mistakes when applying microcement
Now that you know how to apply microcement in the best way, we are going to tell you the most common mistakes when applying it and how to avoid them to achieve an incredible result.
Inadequate ambient temperature
Before applying microcement, it is important to check that the conditions in the room are suitable. Microcement must be applied with an ambient, substrate and material temperature of between 15 °C and 25 °C, and a relative humidity of between 40% and 80%. Working within this range provides the best application conditions and favours an optimal finish, avoiding days of intense cold or heat, which could cause excess humidity or make the material dry too quickly.
It is common to carry out renovations above or below that range. If that is your case, it is advisable to condition the room beforehand. From +5 °C, a heating system can be used to generate uniform and gradual warming, avoiding directing heat sources straight at the substrate. In the event of temperatures above +30 °C, the temperature can be reduced by ventilating during the coolest hours of the day, preventing direct sunlight from entering and, if necessary, using air conditioning or ambient cooling systems indirectly.
It is also important not to apply microcement on cold, frozen, frosty or condensation-covered substrates, nor on overheated surfaces, exposed to direct sunlight or subjected to wind or draughts. These conditions could cause premature water evaporation, loss of adhesion, trowel marks, porosity, surface cracking or colour differences. Once the area has been conditioned, the ambient conditions must remain stable throughout the entire application and drying of the system to avoid problems in the final finish.
Not respecting drying times
If haste sometimes gets the better of you... we understand! But it is true that one of the most common mistakes when applying microcement is not letting each coat dry properly. So if you want an optimal result, no rushing and plenty of respect for the drying time between coats — that way you will avoid damage to your microcement.
Applying thick layers
The "the more, the better" approach does not apply here. If you think that applying a thick coat will speed up the job, let us tell you that it is not true. Applying thick layers will get you nothing but tickets for the cracks and fissures raffle. Remember: it is better to apply thin layers.
Not preparing the surface properly
An optimal, well-prepared surface becomes the perfect base on which to apply microcement. If the surface has cracks, residues from other materials or irregularities, the microcement's adhesion will not be perfect and, therefore, the final result will not be what we want, because over time these imperfections will become visible in the microcement. Tip: repair everything beforehand, because microcement is a decorative coating, not a repair or levelling product.
Negative moisture
Negative moisture is typical of humid environments (as the name suggests) and, in certain areas, there may be moisture that is imperceptible to the eye. With this in mind, the best prevention against this factor is to apply a good primer. This way, you avoid the consequences of damp filtering through and staining the outside of your beautiful microcement.
Mixing the pigment badly
If the manufacturer's instructions are not followed when mixing the pigment correctly, lumps and irregularities may appear, and it may also happen that the colour is not even.
Poor or incorrect sealing
Not sealing the microcement correctly is another of the most common mistakes during its application. The varnish or sealing product will turn the microcement into a water-resistant material, among other things, and, in many cases, into an anti-slip material.
Incompatible materials
It is very important to choose the materials well based on the characteristics of the surface material you want to coat. An absorbent material will not have the same characteristics as a non-absorbent one and, therefore, the primer will be different. The result of getting the choice of materials wrong? A complete disaster.
Low-quality materials
If you want to obtain the best results, you must use materials of the best possible quality. Do you know what cutting costs on material quality guarantees you? Cracks, fissures or detachment in the final result, without a doubt.
Poor or dubious-quality tools
The same thing that happens when you use low-quality materials happens when you use tools of poor or dubious quality. Saving a few cents on tools is like giving a marker to a small child: a lovely wall covered in scribbles. So how you want your microcement to look once applied is up to you.
What substrates can I apply microcement on?
The golden rule: the substrate must be sound, rigid, stable, clean and flat. If that is met, microcement adheres to almost anything: plasterboard (with a primer for absorbent substrates), tiles and ceramic (filling joints and grooves beforehand with a levelling filler and priming), concrete slabs, screeds and levelling layers (smooth, solid and crack-free), painted surfaces (if the paint is well bonded) and even rigid wood furniture such as MDF, stone and marble.
Two important exceptions: parquet and natural wood are not valid substrates — wood "works" with temperature and humidity and the microcement would end up cracking — and surfaces with permanently standing water, such as washbasins and bathtubs, require professional products and labour: they are not a DIY project. You can find more detail on the particular case of bathtubs in our microcement bathtub guide.