Don’t make these mistakes when it comes to sealing microcement surfaces!


Microcement sealing is the last stage of work. It is the sealer that is responsible for the final look of the surface and protects the microcement against stains and scratches. Today we advise you on how to avoid the most common mistakes when it comes to sealing microcement surfaces.


1. Working in too high or too low temperature

The optimal temperature for  microcement system application is 15-25 degrees C. It is also important to protect the packaging with varnish from frost and from overheating. You should not leave sealer containers in a cold car overnight or in the open sun. Frozen varnish, just like paints or other coatings, loses its properties and should not be used.


microcement sealer application mistakes

Accurately weighing out the paint ingredients is essential, and any professional contractor needs to have a good weight.

2. Incorrect mixing of the sealer components

The best microcement sealers are two-component polyurethane sealers. Directly before varnishing, either mix the entire contents of the kit or – in the case of large surfaces – measure the appropriate amount of varnish and hardener that is needed to cover the entire surface. A common mistake is to confuse the volume ratio with the weight ratio. The technical data sheets and the varnish label contain information on the mixing ratio. In the case of Festfloor products, the given proportions are always by weight and you should use a precise scale to measure them. It should also be remembered that the mixed sealer has a limited pot life (also indicated in the technical sheet and on the packaging), after which the varnish dries and is not suitable for use. No, mixed sealer cannot be used the next day;)


3. Coating the microcement using an unsuitable roller

The roller for microcement sealer application must be of good quality, it cannot dust and leave lint, and the bristles should not be too long or too short. For spreading Festfloor sealers, we recommend using a microfiber roller (or nylon) with a bristle length of 8mm. It will ensure even distribution of the varnish.


4. Applying too thick layers

The sealer is applied in two thin layers. Picking up more sealer will not speed up the work, on the contrary – it can make it longer. Applying too thick layers results in the appearance of stripes and marks from the roller and can lead to a situation that the world simply runs out of varnish when applying the second layer.


microcement sealer application mistakes

Painting coverall and full face mask – suitable outfit for solvent-based sealer application

5. Applying microcement sealer without protective clothing

Application of microcement sealer to floors – requires wearing a protective painting coverall with a hood and shoe covers. This way sand from shoes or hair will not fall on the freshly varnished surface.


6. Application of solvent-based varnish without a suitable mask

A solvent-based varnish, eg PU Fest Turbo, provides stronger protection and is recommended to be used primarily in areas with intense pedestrian traffic and outdoors (Also read: Which microcement varnish to choose?). When mixing and applying the varnish, in addition to the protective suit, use a gas mask. Inhaling vapors while mixing, applying and drying the sealer may cause drowsiness or dizziness. Adequate ventilation of the room must be ensured until the sealer is completely cured.



7. Sealing at night and in low light

It’s best to start sealer application in the morning, when there is the most daylight in the room. If you seal in the evening and at night, you cannot see exactly where you have already applied the varnish and where not, and as a result, there may be stripes from the roller and places on the floor without varnish at all.


8. Lack of protection of the varnished surface while the varnish dries

When sealing outdoor surfaces, e.g. terraces or balconies, pets or insects may enter the surface. It can also win strong wind and transfer sand and other impurities to the paintwork, or it can rain, so it is important to protect the varnished surface until the sealer dries completely. All you need is a piece of foil and makeshift railings.


9. Continuation of finishing works without adequate protection of the varnished surface

In a situation where construction or finishing works are to be carried out after the application of the microcement, it is necessary to ensure the protection of the painted surface. After the varnish has hardened, it is best to apply a painting mat (felt floor covering). It is a much better solution than ordinary painting foil or construction cardboard.