What is hydrophobization?

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Until recently, I had only heard about the waterproofing membrane. Builders now put "hydrophobizer" for walls in the estimate. What is it? Do I have to apply it?



To protect porous building materials from external moisture, reduce water permeability and wetting by water, they are impregnated with special chemical compositions (hydrophobisers). This method of treating the surface of building materials is called hydrophobization.

It is used to protect fragile and quite porous materials, such as gypsum and aerated concrete, as well as quite hard and dense materials, such as concrete or natural stone in basements, foundations, facades, walls, tunnels, etc.

Porous mineral materials (with a porous structure) that are used for building structures are negatively, even aggressively, affected by moisture from the surrounding area (rain, fog, snow, meltwater, groundwater...). As a result of such impact we sometimes observe salt stains on brick walls, destroyed (peeling) foundations, faded marble with typical whitish stains, torn off peeling plaster or facade cladding.

Hydrophobization sharply reduces the water absorption of the treated surface.

The process consists in applying acrylic-based or, less frequently, silicone-based compositions to porous surfaces in order to impregnate them. Depending on the porosity of the material, the impregnation depth can vary from a few millimeters to several centimeters. As a result, the treated material becomes water-repellent and its frost resistance increases.

During application of protective compositions, in capillaries and pores of porous material a chemical reaction occurs which forms insoluble crystals, blocking access of moisture inside the material. At the same time the crystals allow air in – the treated material "breathes".

The main properties that material treated with hydrophobics acquires: water-repellent properties, protection against "efflorescence",  increase of heat-insulating properties, because the material stays dry all the time, increase of frost resistance, prolongation of service life of finishing materials applied to treated surfaces. Microorganisms do not develop on the surface, the material does not succumb to erosion. The durability of the material and the whole structure increases. Consumption of paint and varnish materials decreases.

The treated materials retain these characteristics for about 10 years. If hydrophobisers are added to the mixture during the manufacture of building materials, hydrophobic properties are retained throughout the life of the material.


Hydrophobizer is a special compound which forms a protective film on the surface as a result of the surface (we are talking about porous substrates, such as bricks) acquires water-repellent properties.

And moreover, the same protective film vapor permeable, that is, the surface under the hydrophobizer "breathes" that is important.

In other words, the surface after treatment with hydrophobisator "breathes" but at the same time it does not get wet.

Among other things, the hydrophobizer protects the material from degradation, prolongs its life.

In addition to bricks hydrophobizer can be applied to other substrates (concrete, building blocks, etc.).

The hydrophobizer can not only be applied to the surface, but also to act as one of the components (additives) in mortars (masonry, plaster mortars, for example), or as an additive in the manufacture of those very building materials.

Advantages of hydrophobization:

The surface becomes more resistant to various chemically aggressive substances.

Surface is given antifungal, antibacterial properties, i.e. appearance of fungus and mold on such surface is unlikely.

Prevention of efflorescence, that is, it is easier to prevent their appearance than to deal with the consequences.

Thanks to the protective film surface is reliably protected from dirt, oil pollution, etc., and plus for such a surface is easier to care for.

Aesthetic component is also not in last place, the surface with a protective clear film looks much more attractive than the same brick with whitish scaling (efflorescence).

The hydrophobizer can be applied to the surface with a brush and roller, or by spraying.

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