Tips for the application of polyurethane varnish

Great projects will catch the eye by taking care to the smallest details in the finishes. When we think of details, we think of harmony, elegance and highlighting the natural beauty of the space. But the journey to reach excellence in finishes cannot be accomplished without the help of polyurethane varnish. .

It is an ideal material for any decorative covering due to its high properties of hardness, resistance and strong adherence, which makes it withstand friction, abrasion and the passage of time very well. In other words, we will achieve a long-lasting, resistant and natural-looking finish. But what are polyurethane varnishes?

A two-component polyurethane varnish has the characteristic of having good performance and chemical resistance. It consists of an A component containing the polyol and a B component containing the isocyanate. When component B is mixed with component A in the specified proportions, the polyurethane polymer is produced. So once they are mixed, just apply.

Roller for applying polyurethane varnish on a blue container

Preparación del soporte para aplicar el barniz poliuretano

The first step to assure a correct application of the polyurethane varnish is to prepare the substrate. It must be clean and free of grease, dust or dirt of any kind.

If the surface has been previously varnished, it is necessary to sand it and remove all the previous layer. The removal of the previous coating can also be done by stripping, which means removing the existing surface finish coat so that a new coat of varnish can be applied. It is necessary to strip completely the existing layer where we want to apply the new varnish.

If the substrate is damaged and needs to repair or seal the joints, it should be done before varnishing.

On wooden surfaces, before applying the varnish, it is recommended to seal the substrate with a wood sealer varnish and sand it. On cementitious surfaces, it is advisable to first apply a primer to facilitate the bond between the coating and the sealing varnish.

If the surface is metal, the first step is to make sure that it is completely clean and check that there are no traces of rust or dirt. If the substrate is in a bad state of paint, it is necessary to sand the surface by or strip it and then clean the surface. The next step is to apply a metal primer to prepare the substrate to be painted.

Apply polyurethane varnish on microcement

To apply a polyurethane varnish on a microcement coating, it is advisable to first apply a pore sealer primer such as MyCover. This product is a water-based acrylic resin that acts as a bonding bridge and guarantees a quality application.

Roller for applying polyurethane varnish

The pore-covering primer that facilitates the bond between the microcement and the polyurethane varnish is applied in two coats. The second coat needs a drying time of 4 hours before applying the polyurethane.

To work with polyurethane varnish, it is important to have good ventilation and at temperatures between 15 and 30°C . You can work with different tools from a spray gun to a roller or a brush. Any of these three tools can be used to cover the surface to ensure a complete application of the material.

In the case of MySealant 2K polyurethane varnish, the application is done in two coats and each coat needs a drying time of 12 to 24 hours, depending on the environmental conditions in working places. Polyurethanes reach their full chemical properties in 7 to 14 days after the second coat is applied.


The durability, high resistance and hardness of polyurethane coatings make them easy to maintain. The polyurethane should be left to dry for at least a week before it can get wet and the most important thing is when cleaning the surface, avoid to use aggressive products such as salfumán or bleach.

The use of detergents is not recommended and within the first two weeks, the surface should not be covered , because this may cause stains or bleaching of the coating. Cleaning the varnished surface with a wet cloth and neutral soap is the best way to ensure proper care.

To prevent scratches, it is essential to clean daily to remove dust and dirt that may remain on the surface due to daily activity. A good resource is to wipe the surface once a week with a slightly wet mop.

To clean the surface with specific products, we should always follow the volume recommended by the manufacturer for the sake of safety. Cleaners with a high descaling potential guarantee that they will renew the protective layer and provide an extra protection without affecting the varnish.

And in the case of stains, you should follow: the quicker you act, the easier they can be removed. Always avoid using steel scourer , because they can cause scratches. A well-known advice: prevention is better than cure. The more we take care to keep clean, the better condition the varnish will be .