Regardless of what kind of finishing the walls will be – paint or wallpaper – they must first be leveled. And gypsum mixes turn out to be a very popular material. Our advice site will tell you about the features of gypsum mixes, their types and scope.
The basis of such dry mixtures, as the name implies, is gypsum, that is, calcium sulfate hydrate. It is obtained from gypsum stone, which is fired and crushed to a state of dust. In addition, gypsum-based building mixtures may include:
- Whitewash, lime or metal salts that provide the whiteness of the composition;
- Foam glass, perlite and vermiculite. Their task is to reduce the weight of the mixture, as well as reduce heat transfer;
- Additives for adjusting the setting, drying of the coating;
- Components for increasing the strength of the finished coating.
All components are environmentally friendly, gypsum mixtures are completely safe for residents of the house. The dry composition is diluted with plain water, according to the instructions.
In comparison with concrete-cement mixtures, gypsum has several advantages:
- The adhesion rates are high, you can refuse the reinforcing mesh;
- The coating is even, white, without grainy inclusions;
- The weight is less, that is, even with a thick coating layer, the load on the walls will be small;
- No shrinkage. The walls will be smooth, without cracks;
- The maximum layer thickness is up to 5 centimeters;
- Higher rates of sound insulation and heat preservation in the house;
- Hygroscopicity. The gypsum coating will remove excess moisture from the room, which improves the microclimate;
- High plasticity, it is easier to work with gypsum mixtures.
Proponents of using concrete-cement mixtures make such a compelling argument as price. Yes, gypsum mixes are more expensive. But they also have less consumption. For 1 square meter, up to 16 kilograms of a mixture based on cement and only 10 kilograms on a gypsum basis is used. Therefore, there is no need to talk about significant savings on the cost of the compositions. The difference in price is offset by the lower consumption of gypsum mixture.
If we talk about the disadvantages, then gypsum sets faster than concrete mortar. Therefore, such mixtures need to be diluted in small quantities, smoothed on the wall immediately. However, this feature does not bother specialists. Home craftsmen need to take this moment into account when performing work..
Gypsum-based compositions are as follows:
- Plastering. Quite grainy, rough, used in the process of rough leveling of walls;
- Putty. It is a lighter, plastic, grain-free plaster. Used as a finishing layer before painting or wallpapering. The portal devoted a separate article to the choice of putties;
- Assembly dry mixes. Designed for the construction of gypsum board partitions inside the house, leveling the gypsum board;
- Grouting mixes, fill voids and seams well;
- Gypsum polymer. The additive in the composition of polymers gives frost resistance, increases the strength of the coating;
- Floor leveling mixtures. Cement is added to the composition.
Gypsum mixtures are stored and transported in special kraft bags, they have an inner layer of polyethylene, which protects the composition from moisture. The shelf life in a closed bag does not exceed 6 months. After opening, the dry composition will begin to quickly absorb moisture, therefore it is not stored for a long time. The standard weight of one package is 25 or 30 kilograms. But there are also small bags weighing 5 and 15 kilograms.
Gypsum compositions are versatile and can be applied to various substrates:
- Concrete walls pre-treated with concrete contact;
- Cement plaster;
- Clay walls;
- Old plaster, also made of plaster. Of course, if the previous coating has retained its strength;
- Expanded clay concrete, aerated concrete and foam concrete blocks.
To work with gypsum mixtures, you first need a mixing container and a construction mixer. Its use will allow you to get a homogeneous composition, without lumps. In addition, different sized trowels are required for application to walls. After drying, the coating on the walls and ceiling is rubbed and sanded so that the surface is as even as possible. If you plan to create a relief surface, textured plaster, then use rubber rollers with a pattern. Or improvised devices – up to an ordinary broom and brushes.
The most popular manufacturers of gypsum mixes on the Russian market are Volma Stroy, Prospectors and Knauf. The average price of gypsum-based plaster is 375 rubles per 30 kilograms.