Cement plaster: selection and application

Cement-based plaster is one of the strongest and most durable. A layer of plaster will provide not only sanitary, but also aesthetic function. First of all, it is needed to level the walls and protect them from all kinds of damage, and in addition, it will play the role of a heat insulator and sound absorber.

Cement plaster is used for:

• finishing of various facades;
• leveling surfaces in spaces where there is no heating, or in rooms with a high degree of humidity;
• sealing seams or cracks in walls outside and inside buildings;
• leveling surfaces with significant defects;
• to prepare the walls for tiling.

The main advantages of such compositions include:

• plaster has excellent coating strength;
• cement mortar has high adhesion to brick and concrete surfaces, filling even small cracks. The coating itself comes out completely smooth;
• resistance to temperature differences;
• well-known durability;
• also a plus can be considered the simplicity of preparing the solution: it is often made at home, simply by simply mixing all the components used in the right proportions;
• affordable cost for the average man in the street.

But such coatings have several disadvantages:

• complex installation;
• the surface comes out rough, for this reason it will be necessary to apply another finishing gypsum layer if the wall is being prepared for painting or wallpapering;
• the cement mortar makes the walls heavier, and the impact on the foundation then increases;
• almost complete lack of adhesion to wood and painted walls;
• the mixture shrinks and can crack if applied too thin.

Main technical characteristics of cement plasters:

• Density... The strength of such a mixture will directly depend on the density coefficient.
• High heat conductivity.
• Vapor permeability... To avoid condensation, wall coverings must absorb excess moisture and move it outside.
• Drying time... The greater the thickness of the coating, the longer the drying time will also be, therefore it is best just not to touch the applied plaster from the cement base for at least a day.

Cement quality plaster product has two main varieties.

The composition of these products contains water, a certain type of sand and the grade of cement you need, while all the elements are mixed in precisely calculated proportions. The strength of this dry coating will depend entirely on the characteristics of the cement. For example, cement M150-200 is chosen only for installation inside various premises, and more resistant cement of the M300 grade and higher is chosen for high-quality plastering of external facades.

The proportions of sand and cement base for making the mixture will also depend on the fractions of the selected sand, the desired final strength or the scope of use.

Fine sand is used for finishing work. Barite sand and serpentinite sand provide protection from various kinds of radiation.Metal shavings (dust can also be selected) are often used in a cement mixture, it gives it excellent strength and toughness. Marble flour and coarse-grained sands are used as decorative facade coatings.

It is allowed to use cement without the presence of sand only for filling small cracks, for leveling the same various coatings, the composition without sand is not used.

Using too fine sand will be undesirable, as the plaster can produce very impressive potholes. The presence of a huge amount of various impurities in the sand leads to cracking of the finish as a result of its weakening.

The quality of the final surface will directly depend on the subspecies of the selected sand. The best option is river and washed sand with parameters 0.5-2 mm... Excessively large grains of sand will give the wall surfaces a noticeable roughness.

Sand with parameters of 2.5 mm is chosen only for brick coatings, and sand larger up to 0.5 cm is used when installing reinforced concrete structures.

Polymer and polymer-cement types of mixtures are selected both for high-quality outdoor work and for work inside the building.

These types are not intended for the initial alignment of the walls, but only serve for their finishing. Unlike typical mixtures, these products include all kinds of additives - plasticizers and reinforcing elements.

To make the weight of the plaster mixture less, slaked lime is included in it. If such extinguishing is done by hand, then this lime must be withstood for at least 2 weeks.otherwise the finish may bulge and flake. A properly made mortar gets excellent strength.

The main advantages of such mixtures include:

• good adhesion to many building materials;
• antibacterial properties;
• excellent plasticity of the mixture throughout its entire service life;
• vapor permeability, which creates a high-quality microclimate in the room;
• resistance to various abrasions.

Disadvantages include:

• low resistance to impact and stretching (as well as compression);
• the lime part makes the cost of the mixture higher.

Most often, their volume in such a mixture will not exceed 1%. The lime part perfectly improves the quality characteristics of the cement.

TsPSh perfectly withstands changes in humidity and various temperatures. It is the best choice for exterior decoration of a building when there are no special requirements for this product.... This mixture helps to correct all wall irregularities after they have been insulated with cotton wool and foam, and also creates a much-needed layer of thermal insulation.

A cement-sand mixture is chosen for spaces with a high degree of humidity, as well as before rapid painting or before starting tiling.

With the help of DSP, surfaces that have significant irregularities are equalized, seams between panels are sealed with them, various defects are eliminated - this is the most inexpensive way to get rid of them for a long time.

To eliminate minor defects, it is best to apply putty compounds, and in order to get rid of curvature with drops of up to 5-7 cm, it is better to choose plasterboard cladding or special panels for the walls.

Lime-based compounds are selected in order to level foam blocks, concrete walls, any brick and woodto eliminate cracks and all kinds of irregularities.They are suitable for preparing walls for finishing work: applying textured plaster, painting, pasting various types of wallpaper and facing with ceramic tiles.

You can also purchase universal brands that are perfect for both facade and interior work. In addition, they differ significantly from each other in the way they are applied - manually or using a typewriter.

Lime mortars are hypersensitive to certain installation conditions, for example used at a positive temperature from 5 to 30°C... Mixes that are recommended for use at any degree of humidity can be chosen for bathrooms and swimming pools.

If you need to choose a cement plaster for facade and interior work, then first you need to carefully familiarize yourself with its quality characteristics.

Cement-lime plaster is a very plastic, the lightest, but at the same time an unusually soft substance. This type of plaster will require final finishing with putties. For work with walls outside the building, this type of mixture is not used., but for internal installation work they are constantly used.

Facade plaster is designed to perform 2 main functions:

• protect - first of all, from atmospheric precipitation, so that the walls do not get wet from rain and snow. It will also protect against noise, limiting the penetration of various kinds of sounds into rooms. In addition, it improves the thermal insulation of the walls and gives them uniformity;
• decorate - aligns the walls, prepares them for painting with paint. In addition, such plaster itself can have an original texture and interesting colors. It also helps to hide small spots and cracks.

The plastered surface will constantly be in contact with the external environment, therefore, such a plaster must have frost-resistant, moisture-resistant characteristics and inertness to UV radiation.

There are several types of sand mixtures, which can be different in their composition and area of ​​use:

• Simple - usually applied in 2 layers ("spray" and "primer"), it does not need beacons and "cover". This product is often found in rooms where the most even and smooth walls are not needed, such as in the same basements or damp cellars, in sheds and attics, as well as in all damp rooms. Its main purpose is to qualitatively repair holes, chips and other defects noticeable to the eye, to carry out hygienic processing of wall coverings.

• Improved - application is used in 3 or more approaches (a “cover” is added to “spraying” and “soil”), the last layer is equal to such a device as a trowel. This is one of the most popular types of mixes, which is chosen when working with walls inside buildings and for finishing their facades. The result is a flat and perfectly smooth wall with precisely adjusted corners.

• High quality (universal) - here it is necessary to install beacons, at least 5 layers are applied ("spray", 2-3 layers of primer and "cover"). "Nakryvka" is advised to be fixed with cement in order to make the waterproofing (moisture-resistant) properties higher and more durable - the wall surface. The mortar is used for indoor and outdoor applications that require the highest possible quality.

The main rules for working with cement-based mortar:

• the walls are first treated with a special primer to improve adhesion, and therefore they are thoroughly dried;
• to create a flat plane, guides - beacons are fixed on the wall. If the wall area is small, the beacons are replaced with mortar slaps, the height of these slaps is set at the building level;
• instead of beacons, you can take a metal profile. It is fixed to the walls with putty. In addition, you can create beacons from wood slats, they are fixed on self-tapping screws. The most important thing is not to forget that the beacons should be located at a distance of 10-20 cm less than the width of such a tool, as a rule, all the layers of the coating will equal them;
• the finished plaster is applied to the walls with a trowel, and in order to create a thick layer, a ladle is often used. The very first layer of plaster is called "spatter" - it is a quality base for all subsequent layers.

• The second layer is placed from bottom to top, hiding the previous layer underneath. It is best to carry out the work in sections of 1-1.5 m. After the plaster should be stretched and leveled with the rule. It is pressed as tightly as possible to the lighthouses and led upward, while slightly moving the rule from right to left. The excess solution is removed from the tool with a trowel, and when voids are formed, the mixture is added to the right place with its help.

• This is how the entire gap between the two beacons is processed, after which you can move on to work.
• To smooth out small defects, beacons can be omitted. The work is then carried out using a different technology. After "spraying", the solution is spread with a spatula from bottom to top.
• To make the surface of the wall even smoother, you need to use another "cover" with a liquid mixture. Use proportions of sand and cement as 1: 1 or 1: 3.
• After the application process, while the cement-sand coating itself has not yet matured, it is carefully rubbed. Using a float, insignificant irregularities, various protrusions or visible grooves are removed in a circular motion.
• After drying, the wall covering treated in this way will be completely ready for finishing. The cement plaster will dry in 4-7 days at normal indoor humidity.

The plaster can be applied manually or by machine, which method is preferable for you, you will learn from the recommendations on the package of a particular mixture, and the minimum thickness of the applied solution will also be indicated there. The plaster wall covering machine helps to improve the quality of the work carried out and save money.

For information on how to make a mixture for cement plaster, as well as correctly apply it to the wall, see the next video.

DSP from the company "Miners" created on the basis of a high-quality brand of cement M-500. According to consumer reviews, it has excellent plasticity and a fairly economical consumption, only 12 kg per square meter. The term of use of the solution is one and a half hours.

Cement-sand and at the same time universal mixture from this manufacturer has high elasticity and excellent vapor permeability. Not afraid of frost. The greatest thickness of the mortar application is 30 mm.

Brand "CR 61" from "Ceresit" used to level brick and stone masonry, and is also often found in restoration work. To obtain a solution for 25 kg of the mixture, 6.7 liters of water are taken.

CT 29 can also be used as a quality filler. The thickness of any layer should not be more than 20 mm. Has a high vapor permeability and resistance to negative climatic manifestations. "CT24" is selected for aerated concrete surfaces, plastic, vapor permeable and resistant. It contains no harmful chemical components, so it is considered the most environmentally friendly product.

Brand "Adhesive" from the manufacturer "Knauf" It contains a cement base, quartz and lime fillers, as well as various kinds of additives. Produced for the primary treatment of walls. When using it, a rough texture is created. The mixture qualitatively regulates water absorption, can serve as a substitute for reinforcing nets.

The Zokelputz brand contains cement, sand and additives that increase adhesion.It can be used as a plinth cladding. "Unterputz" is chosen for rooms with a sufficiently high humidity. Reduces moisture absorption at walls that have pores. Can be applied in a thin layer without the fear of cracking.

Cement plaster M-100 from "Besto" - this is a ready-made composition, which is designed for the fastest possible preparation of a plaster solution. The choice of such formulations helps to qualitatively improve the microclimate in any room. You can use this composition when carrying out internal and external work using plastering stations.

It is used to level brick and stone masonry, and is also often found in restoration work. To obtain a solution for 25 kg of the mixture, 6.7 liters of water are taken.