Primer for concrete floor: selection criteria

Gusevsky Andrey Anatolyevich

Materials for concrete floor: screed primer

Concrete is considered one of the most durable materials. And, nevertheless, without proper soil treatment, it collapses quite quickly.
How to primer a concrete floor, and what compositions can be used at all for this purpose? The answers to these, and many other questions, will tell you our instructions, as well as the video in this article.

Why primed concrete

The need for processing any concrete base arises in three cases. These are: the need to strengthen the loose structure of concrete; its water resistance throughout the entire thickness, and the creation of an adhesive film on the surface for subsequent glue finishing.
Protection of concrete structures is regulated in the construction of GOST 31384 * 2008. According to this document, the treatment with hydrophobic, coating and plastering compositions refers to measures of secondary protection of concrete.
They are carried out in cases where proper protection cannot be provided by primary measures, which include additives introduced into the composition of concrete.

Special Protective Compounds

A variety of composition for protecting a concrete surface should be selected in accordance with the degree of environmental aggressiveness. So, to decide what to ground the concrete floor with should be based on the functionality of the room.
If we are talking about a residential building, then here the main indicator of the aggressiveness of the environment is humidity. Where water leaks are likely, the concrete floor base (seePrimer for floors - features of application) must be treated with a hydrophobic compound.

Biocidal primer for concrete floor

So:

• On the floors of the first floors of buildings, especially if there are damp basements under them, mold often forms. For their processing, it is better to prefer the deep penetrating biocidal soil composition, which you see in the photo above.
  This soil option is “two in one”: it prevents the formation of fungus (seeAntifungal primer - purpose and characteristics of the material), and improves surface adhesion.
• If we talk about production facilities, then the aggressiveness of the environment in them may be completely different from that in a residential building. Accordingly, the protection of concrete substrates must take into account specific conditions.

Here is a brief table explaining how to treat a concrete floor in case of contact with an aggressive environment:

Soil sample	What aggressive environment is this protection for?	Material Category
Two-component epoxy paint	Exposure to gaseous substances (aerosols).	Special-purpose paintwork.
Bituminous mastic	Direct contact of the concrete surface with a solid aggressive medium or liquid.	Coating insulation.
Primer polyurethane for concrete	The action of aggressive fluids of various origins.	Waterproofing impregnation with chemical resistance.

• If you think about how to primer the concrete floor in the garage, where oil or gasoline can drip onto concrete, then there is no better option than a polyurethane primer. And if you use epoxy paint, then it will also serve as a decorative coating.

But let's just say that this pleasure is not cheap. The price of a 2.5 liter can varies between 6500-7000 rubles, but it is enough to paint 25-30m2 of the floor. Moreover, one coat of paint for high-quality protection of concrete is quite enough.

Hydrophobic and adhesive primers

There are various variations of primers with a hydrophobic effect - they should prevent the penetration of moisture into the pores of concrete.
Most of them are organosilicon compounds:

• The main disadvantage of these soils is the fact that under the influence of the alkaline environment of the concrete itself, they eventually lose their protective effect. Therefore, after a certain time, the open surface of the concrete has to be reprocessed.

Silicone-based waterproofing primer

• The silicone primer that you see in the photo can do much better with waterproofing. There are many other types of modern options for soil for concrete, which include special cements and active additives, for example: Penetron-Admix, Kristallizol, Gidroteks.
• At its core, it is penetrating waterproofing materials. They penetrate deep into the concrete, crystallize there, displacing existing moisture, and preventing it from entering again.
  This property of the soil allows you to use it even if the concrete base is damp. It also protects concrete from aggressive environments, so it can be fully considered universal.

Crystallizing concrete primer

• When arranging floors of dwellings with normal humidity, use compositions on an acrylic basis, providing strong adhesion of glued surfaces. These are well-known soil options called primer "Concrete contact" in various variations.

It is not suitable for processing the base of the floor in bathrooms, since protection for concrete, in fact, is not. This type of soil creates only a surface film that promotes good adhesion of the layers.
And with high humidity, we need such compounds that close the pores and have adhesive properties - we talked about them above.