Water repellents – where they are used, features, characteristics

Water repellents– special compounds, substances that are used to protect surfaces and materials from moisture. Hydrophobic (water-repellent) properties are an important characteristic of building materials, especially if they are used in outdoor conditions or in wet rooms..

Especially important is hydrophobization, that is, treatment with water repellents, for porous building materials such as aerated concrete, foam concrete, brick, wood.

Why is it dangerous for moisture to enter the pores of building materials:

• When water freezes, it expands, destroying building materials from the inside. If the temperature changes several times during the day, the water freezes and thaws many times, very negatively affecting, for example, the brick facade of the house;
• water dissolves salts, efflorescence appears on the brick;
• microorganisms will actively multiply in wet materials, which can cause the appearance of fungus and mold.

If the surfaces are treated with water repellents, they are practically not wetted with water. Moisture is simply not drawn into the capillaries, does not penetrate into the material. As a result, the service life of, for example, paving slabs and brick facades is significantly increased, the surfaces look better.

There are two options for carrying out hydrophobization:

1. Volume. This process is carried out directly during the creation of building materials, water repellents are added to the solution, a mixture for forming bricks. That is, water repellents serve as one of the useful additives in the production process. Roof tiles, chipboard and gypsum fiber boards, other materials are also usually processed, impregnated with water repellents in production. In the conditions of the construction of a private house, volumetric hydrophobization can be used when creating a mortar for laying bricks, pouring a foundation;
2. Surface. This type of hydrophobization is already used in construction and decoration. For example, a finished brick facade is treated with water repellents..

Volumetric hydrophobization does not always become a guarantee of reliable and durable protection. Additives to a concrete solution or a mixture for forming bricks, of course, will increase the water-repellent qualities of materials, however, for additional protection, experts advise using surface hydrophobization.

The main advantages of hydrophobization:

• the facade, sidewalk or brick fence will dry up instantly even after heavy rain, no wet spots will appear;
• if you treat the tiles on the porch, garden path made of stone with water repellents, this significantly reduces the risk of ice formation, which can lead to injuries;
• the facade, sidewalk or fence, surface treated with water repellents, retain their original appearance longer, look more attractive;
• the surface will be protected from the appearance of moss, mold, the development of microorganisms;
• natural air exchange is maintained, the surface continues to “breathe”;
• increases the service life of materials;
• the risk of efflorescence is reduced.

In addition, facades treated with water repellents resist dust and dirt much better, they are easier to clean. The frost resistance of materials and their thermal insulation properties also increase..

As you can see, there are really a lot of benefits from water repellents. As for the composition, water repellents can be based on:

• potassium alkylsiliconates (water-soluble);
• alkoxysilanes;
• hydro-containing siloxanes (H-siloxanes);
• hydroxyl-containing siloxanes (these are rubbers, silanesiloxanes, allowing to achieve the effect of a wet stone and deeply penetrating the surface).

We would like to emphasize that today almost all water repellents are produced on the basis of organosilicon compounds, that is, silicones or siloxanes..

When choosing a composition for hydrophobization, pay attention to which surface it is intended for. There are universal compounds, but experts advise choosing specialized ones: for bricks, concrete surfaces, ceramic or clinker tiles, and so on. This is the main selection criterion, in addition, there are water repellents only for use as an additive to the solution, that is, for volumetric hydrophobization, for impregnating wood and other materials, for surface application. This is the second most important parameter when choosing a water repellent.

Pay also attention to the consumption indicators of the composition and the duration of its action – manufacturers can give a guarantee for a period of 5 to 15 years.

As for the cost of water repellents, it differs depending on the type, composition, manufacturer. For example, Ceresit CT 10, a siloxane-based water repellent with a volume of 3 liters, costs about 290 rubles, and Ceresit CT 11 based on silanesiloxylane of the same volume will cost about 700 rubles. A liter of water-based water-repellent agent “Sophexil-40” is sold for 280 rubles.

The rules for conducting surface hydrophobization are simple:

• the surface of the facade, garden path from a tile or fence is washed from dirt and dust;
• all efflorescence is removed, if any, you should also remove moss, mold, fungus if necessary;
• after the surface dries, a water repellent is applied. To do this, it is convenient to use a spray, on small surfaces – paint brushes, on a flat wall, for example, a roller is useful.

Experts advise to carry out hydrophobization twice after a short period of time to enhance the protective effect.

There is only one drawback to using water repellents – a rather high cost, especially when it comes to the need to process, for example, the entire facade of a brick house or a long and high fence.