Hydrophobization prevents the possibility of the appearance of saltpetre and „sweating of the walls“. In order to avoid the possibility of the appearance of saltpetre, it is necessary to prevent the process of leaching salt from the wall material. This can be achieved by hydrophobization, by treating the cleaned wall surfaces with a special agent (hydrophobizer), which gives the building materials waterproof properties. After hydrophobization, the surface of the wall stops absorbing water and the water falls off the wall without wetting it.

Materials produced on the basis of organic compounds, silicon (silicon), are usually used for hydrophobization. They create a very thin (monomolecular) coating in the cavities of the material and on its surface, which cannot be washed off with water and which is waterproof. It should be emphasized that organic silicon compounds do not reduce the passage of water vapor – the surface „breathes“ and thus maintains an atmosphere in the room suitable for people to stay. In addition to protection against saltpetre, hydrophobization gives the walls antibacterial and antifungal properties, helps prevent the formation of mold and mildew in the basement.

Tests have shown that with materials treated with such a hydrophobic agent: concrete, ordinary and silicate bricks, wood and others, capillary moisture decreases more than 10 times in 2-24 hours in relation to the untreated surface and amounts to a maximum of 1%.
Later, when absorbing water within 2-7 days, the capillary moisture will not exceed 2%. All this prevents the appearance of saltpetre, cracks, destruction during freezing and preserves the external appearance of the construction.