Cement-based plastering is one of the strongest and most durable. A layer of plaster will provide not only a sanitary, but also an aesthetic function. It is first of all needed to level the walls and protect them from all kinds of damage, and besides this, it will play the role of a heat insulator and a sound absorber.
Cement plaster is used for:
- decoration of various facades;
- leveling surfaces in spaces where there is no heating, or in rooms with a high degree of humidity;
- sealing joints or cracks in walls outside and inside buildings;
- alignment of surfaces with significant defects;
- to prepare the walls for laying tiles.
The main advantages of such compounds include:
- the plaster has excellent coating strength;
- cement mortar has a high adhesion to brick and concrete surfaces, filling even small cracks. The coating itself comes out completely smooth;
- resistance to temperature differences;
- the well-known durability;
- also a plus can be considered the ease of preparation of the solution: it is often made at home, just just mixing in the right proportions all the components used;
- affordable 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;
- cement mortar makes the walls heavier, and the impact on the foundation then increases;
- almost complete lack of grip with wood and painted walls;
- the mixture shrinks, and if an excessively thin layer is applied, it may crack.
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 should absorb excess moisture and bring it out.
- Drying time . The greater the thickness of the coating, the longer it will dry out, therefore it is best not to touch the applied plaster from the cement base for at least a day.
Types and characteristics
Cement quality plaster has two main varieties.
The composition of these products includes water, a certain type of sand and the cement grade 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 selected only for installation inside various rooms, and more resistant cement of grade M300 and higher - for high-quality plastering of external facades.
The proportions of sand and cement base for the manufacture of the mixture will also depend on the fractions of the selected sand, the desired final strength or scope of use.
To lay the middle (soil) plaster layer, you need sand of a certain density and average parameters of 0.5-1 mm with a small amount of sludge deposits.
Fine sand is used in finishing work. Barite sand and serpentinite sand provide protection against various kinds of radiation. Metal shavings (dust can be selected) are often used in cement mixtures, it gives it excellent strength and toughness. Coarse-grained marble flour and sands are used as a facade coating of a decorative plan.
Perlite sand will serve as an excellent heat and sound insulator of the coating. With a shortage of sand, the mixture will dry out too quickly and not very durable.
It is allowed to use cement without the presence of sand only for puttying small cracks ; to smooth out various coatings, a composition without sand is not used.
Using too fine sand will be undesirable, as stucco can produce very impressive potholes. The presence in the sand of a huge amount of different impurities 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 a river and washed sand with parameters of 0.5-2 mm . Excessively large grains of sand will give a noticeable roughness to the surface of the walls.
Sand with parameters of 2.5 mm is chosen only for brick coatings, and sand larger than 0.5 cm is used in the installation of reinforced concrete structures.
Polymer and polymer-cement mixtures are selected for both high-quality street work and for work inside the building.
These types are not intended for the initial alignment of the walls, but serve only for their finishing. Unlike typical mixtures, these products include all kinds of additives - plasticizers and reinforcing elements.
To make the weight of the stucco mixture less, slaked lime is included in it. If such cancellation is done with your own hands, then this lime must be kept for at least 2 weeks , otherwise you can get bloating and delamination of the finish. Correctly made solution gets excellent strength.
The main advantages of such mixtures include:
- good adhesion with 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.
The disadvantages are:
- low resistance to shock and tension (as well as compressions);
- the calcareous part makes the cost of the mixture higher.
To obtain a more plastic solution, as well as increase its adhesion to the desired surface, plasticizers are included in it.
Most often, their volume in such a mixture will be no more than 1%. The calcareous part perfectly improves the quality characteristics of cement.
TsPSh perfectly withstands moisture differences and various temperatures. This is the best choice for exterior decoration of a building when there are no special requirements for this product . Such a mixture helps to fix all wall irregularities after they have been insulated with cotton and foam, and also creates a much-needed layer of thermal insulation.
Cement-sand mixture is chosen for spaces with a high degree of humidity, as well as before quick painting or before laying tiles.
Using DSPs, surfaces that have significant irregularities are equalized, seams between panels are closed with them, various defects are eliminated - this is the most inexpensive way to get rid of them for a long time.
Experts do not recommend the use of cement-sand mortar for ceilings - for this it is better to choose high-quality gypsum mortars.
To eliminate minor defects, it is best to apply putty compounds, and in order to get rid of curvature with differences up to 5-7 cm - it is better to choose a gypsum board lining or special panels for walls.
Compositions on the basis of lime are selected in order to align the foam blocks, walls of concrete, any brick and wood to eliminate cracks and all kinds of irregularities. They are suitable in order to prepare the walls for finishing work: the use of textured plaster, painting, gluing various types of wallpaper and ceramic tile lining.
You will be able to purchase universal brands that are perfect for facade and indoor work. In addition, they differ significantly from each other by the method of application - manually or using a machine.
Lime mortars are hypersensitive to certain installation conditions, for example, they are used at a positive temperature of 5 to 30 ° C. Mixtures that are recommended for use at any degree of humidity can be selected for bathrooms and pools.
Which is better to choose?
If you need to choose a cement plaster for facade and interior work, then first you need to carefully examine its quality characteristics.
For interior work
Cement-lime plaster is very plastic, the lightest, but at the same time it is 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 it is used constantly.
For exterior decoration
Facade plaster is designed to perform 2 main functions:
- protect - first of all, from precipitation, so that the walls are not wet from rain and snow. It will also protect against noise by restricting the penetration of various kinds of sounds into rooms. In addition, it improves the thermal insulation of walls and gives them uniformity;
- decorate - equalizes walls, prepares them for painting with paint. In addition, such a plaster in itself can have an original texture and interesting colors. It also helps to hide small spots and various cracks.
For plaster, which is used for external work, the most important properties will be strength and durability.
The plastered surface will constantly be in contact with the external environment, therefore, such plaster should have frost-resistant, moisture-resistant characteristics and inertness to UV radiation.
There are several varieties of sand mixtures, which may be different in composition and field of use:
- Simple - usually applied in 2 layers (“spray” and “primer”), it does not need beacons and “covers”. This product is often found in rooms where the most even and smooth walls are not needed, as, for example, in the same basements or damp cellars, in sheds and attics, as well as in all wet rooms. Its main purpose is to qualitatively seal holes, chips and other defects visible to the eye, and to carry out hygienic processing of wall coatings.
- Improved - application in 3 or more approaches is used (a “cover” is added to the “spray” and “soil”), the last layer is equal to such a device as a trowel. This is one of the most popular types of mixtures, which is selected when working with walls inside buildings, and to finish their facades. The result is a flat and perfectly smooth wall with precisely calibrated corners.
- High quality (universal) - here it is necessary to install beacons, apply at least 5 layers (“spray”, 2-3 layers of primer and “coat”). It is advised to fix the “Nryvku” with cement to make the waterproofing (moisture resistant) properties higher and more durable - the wall surface. The solution is used when working indoors and outdoors, which require the highest possible quality.
Subtleties of application
The main rules for working with a solution of cement base:
- the walls are first treated with a special primer to improve adhesion, and therefore they are thoroughly dried;
- to create an even plane, guides - beacons are fixed on the wall. If the wall area is small, the beacons are replaced by slaps of the mortar, the height of these slaps is set at the construction level;
- instead of beacons, you can take a profile of metal. 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, they will be equal to all layers of the coating;
- the finished plaster is applied to the walls with a trowel, and in order to create a layer of large thickness, a bucket is often used. The very first layer of plaster is called "spray" - a quality basis for all of the following layers.
The next coat can be applied 2-3 hours after the first coat has set.
- The second layer is laid from the bottom up, hiding the previous layer under it. It is best to carry out work in sections of 1-1.5 m. After the plaster should be stretched and aligned 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. Excess solution from the tool is removed with a trowel, and when voids are formed, it is used to add the mixture to the right place.
- This is how the entire gap between the two beacons is handled, after which you can proceed to work further.
- To align minor defects, beacons can be omitted. The work then is conducted using a different technology. After "spraying" the solution is distributed with a spatula from bottom to top.
- To make the wall surface even smoother, you need to use another “cover” with a liquid mixture. The proportions of sand and cement should be used as 1: 1 or 1: 3.
- After the application process, while the cement-sand coating has not yet become stronger, it is gently wiped. Using a grater, circular irregularities, various protrusions or visible grooves are removed in a circular motion.
- The wall coating thus treated, after drying, will be completely ready for finishing. Cement plaster will dry in 4-7 days at normal humidity in the room.
The plaster can be applied manually and machine, which method is preferable for you, you will learn from the recommendations on the packaging of a particular mixture, the minimum thickness of the applied solution will also be indicated there. The machine for coating walls with plaster helps to improve the quality of the work and save.
See how to make a mixture for cement plaster, as well as how to properly apply it to a wall, in the next video.
Manufacturers and reviews
The DSP from Starateli was created on the basis of a high-quality cement grade M-500. According to consumer reviews, it has excellent ductility and a rather 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 largest thickness of the solution is 30 mm.
The brand “CR 61” from “Ceresit” is used to level the masonry of brick and stone, and is also often found during 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 high-quality putty. The thickness of any layer should not be more than 20 mm. It has high vapor permeability and resistance to negative climatic manifestations. “CT24” is selected for cellular concrete surfaces, it is plastic, vapor permeable and stable. It does not contain harmful chemical components, so it is considered the most environmentally friendly product.
The brand “Adhesive” from the manufacturer “Knauf” has a cement base, fillers of quartz and lime, as well as various additives. Available for primary wall treatment. When used, a rough texture is created. The mixture qualitatively regulates water absorption, can serve as a replacement for reinforcing meshes.
The Zokelputts brand includes cement, sand and those additives that increase adhesion. Can be used as basement cladding. Unterputz is selected for rooms with a sufficiently high humidity. Reduces moisture absorption on walls that have pores. It can be applied in a thin layer without fear that cracks will begin to form.
Besto M-100 cement plaster is a ready-made composition, which is intended for the quickest possible production of a plaster mortar. The choice of such compositions helps to improve the microclimate in any room. You can apply this composition in the implementation of internal and external works using plastering stations.
It is used to level brickwork from brick and stone, and is also often found during restoration work. To obtain a solution for 25 kg of the mixture, 6.7 liters of water are taken.