Building mixtures based on gypsum. Features of gypsum plasters and the rules for their application. What consumers think about Starateli plaster

10.02.2009

Gypsum dry mixes

One of the most important problems of the building materials industry is the development of domestic production of effective building materials based on harmonious and balanced activities in relation to the environment, saving material and fuel and energy resources, and maximizing the use of local and technogenic raw materials.

In this aspect, building materials and products based on gypsum binders (GB) are promising. Gypsum binders and materials based on them have a number of valuable qualities. The production of gypsum binders is non-toxic, characterized by low specific fuel and energy consumption (approximately 4-5 times less compared to cement production). Gypsum materials have good heat and sound insulation properties, fire and fire safety, relatively low density, decorative effect.

In addition, the use of gypsum materials for interior decoration provides a favorable indoor climate due to the ability of the material to "breathe", easily absorb and release moisture. Research on the development of waterproof gypsum binders has expanded the areas of their possible application. Binders of a new generation based on gypsum binders, characterized by reduced water demand and high performance properties, have been developed.

Despite the undoubted advantages of gypsum materials and products over materials based on other binders, the scale of their use in Russia is currently significantly inferior to cement-based products.

The range of gypsum binders produced in the country for construction work is limited to building gypsum produced in accordance with GOST 1 25-79 with a strength range of 3 to 7 MPa.

Anhydrite binder, which is very promising due to the low cost of raw materials and low investment in processing, has not yet found sufficient distribution. Such a binder has the same positive properties as other gypsum binders, and even surpasses it in final strength. It can be used for the same purposes as gypsum binder, including for the production of dry building mixes.

Building mixes made on the basis of gypsum or anhydrite binders are called dry gypsum mixes (SGS).

A distinctive feature of mortars based on gypsum dry mixes, in comparison with cement mortars of a similar purpose, is an increased yield per unit mass of the dry mix. The use of gypsum dry mixes for finishing provides a reduction in labor costs by more than 2 times, and the consumption of the mixture is almost 2 times lower than the cement mixture for the same area of processing.

SGS are homogeneous bulk materials of optimal composition, consisting of carefully dosed and mixed dry components - gypsum binders, fractionated aggregates (fillers), pigments and modifying additives for various purposes.

In accordance with the existing classification, the GHS can be divided into the following main types:

plastering (including decorative and protective);

putty;

mounting;

adhesives;

grouting;

floor (leveling for flooring).

Mixtures based on non-water-resistant gypsum binders are used for interior decoration of buildings and structures with dry and normal indoor conditions, and GHS based on waterproof gypsum binders for finishing work in rooms with normal, wet and wet conditions, as well as when finishing building facades in accordance with current regulatory documents SNiP 3.04.01-87, SNiP 2.03.13 - 88, SNiP P -3 - 79*.

Plaster gypsum mixes

Plaster mixtures are mortar mixtures of non-water-resistant gypsum binders of B- or a-modifications, anhydrite or mixtures thereof, coarse-grained aggregate with a fraction of not more than 2.5 mm and special chemical additives for various purposes. Such mixtures are intended for rough leveling of surfaces by single-layer plastering of walls and ceilings with various types of surfaces (concrete, brickwork, cellular concrete, other rough and corrugated surfaces).

The most famous types of gypsum plaster mixtures include: ROTHBAND, GOLDBAND, GIPSPUTS HP 100, MASHI-NENPUTS MP 75, ACOUSTICPUTS, TEPLON, SILIN, FARVEST-Gypsum, GYPSUM white, GYPSUM gray, CONSOLIT 500, etc.

Gypsum plaster mixtures and solutions from them should be characterized by the following indicators:

bulk density of the mixture, kg/m3 -700...1100;

water-to-solid ratio (the amount of mixing water required to obtain a given mobility of the solution) -0.5 ... 0.b;

solution processing time, min. -50...100;

hardened mortar density, kg/m3 -800...1100;

compressive strength, MPa - 2.5 ... 7.0;

tensile strength in bending, MPa - 1.5 - 3.0;

adhesion strength with the base (surface to be treated), MPa - 0.4 ... 0.7;

storage period, months - 3...6

The indicators of these properties depend on the scope of the solution and its composition.

Putty gypsum mixes

Putty mixtures are dispersed mixtures of non-water-resistant gypsum binders of B- or a-modifications, anhydrite or waterproof gypsum binders (gypsum-cement-pozzolanic or composite gypsum binders), fine and finely dispersed fillers and targeted chemical additives.

Such mixtures are intended for fine and finishing leveling of the surfaces of walls and ceilings; for the final preparation of concrete and plastered surfaces for painting or wallpapering; for facing and restoration works. They are used for sealing longitudinal and transverse joints between GKL and GVL during interior finishing work, as well as seams during the installation of gypsum tongue-and-groove boards. They have good adhesion to various materials and practically do not shrink. The advantage of gypsum putties is their rapid hardening, which allows further finishing work after several hours of hardening.

The most famous types of gypsum putty mixtures include: UNIFLOT; FUGENFULLER; FUGENFULLER Hydro; FUGENFULLER GW; FUGENFIT; FINISHING; UNIS GSH; GSH Slide; UNICE Bleek; R-16 MONOLITH; R-1 7 MONOLITH; GLIMS-Gypsum; PETRO-MIX SHG; ShGL; ShGS; SHGU; KREPS GKL and others.

Gypsum putty mixtures are characterized by the following properties:

hardened solution density, kg/m3 - 1100...1800;

compressive strength, MPa - 4...1 0;

tensile strength in bending, MPa - 2.5 ... 5;

storage period, months - 3...6

Dry gypsum mixes (mounting)

Mounting mixtures are mortar mixtures of non-waterproof gypsum binders of p- and a-modifications or waterproof gypsum binders (gypsum-cement-pozzolanic or composite gypsum binders) with a specially selected complex of chemical additives.

Such mixtures are used in the installation of internal partitions from gypsum tongue-and-groove slabs; when facing internal surfaces with plasterboard and gypsum fiber sheets, as well as when arranging floor bases from gypsum fiber boards.

The most famous types of gypsum assembly mixtures include: PERLFIX, ("KNAUF"), GIPSOKONTAKT ("Bolars"), VOLMA installation (JSC GIPS, Volgograd), etc.

The main physical and technical characteristics of some types of gypsum assembly mixtures are as follows:

bulk density, kg / m 3 - 800 ... 950;

water-solid ratio - 0.4...0.6;

solution processing time, min. - 60...120;

hardened mortar density, kg/m3 - 1300...1350;

compressive strength, MPa - 4...7.5;

tensile strength in bending, MPa - 1.5...5;

adhesion strength, MPa - 0.3 ... 0.7;

storage period, months - 6

Dry gypsum floor mixes (levelling)

Dry mixes for flooring are mortar mixes of non-waterproof gypsum binders a-modification, anhydrite, estrich gypsum or waterproof gypsum binders (gypsum-cement-pozzolanic or composite gypsum binders) and a special set of chemical additives to increase the plasticity of the mortar while reducing the water content.

The most well-known types of gypsum mixtures intended for the installation of floor bases include ATLAS SAM 200 mixtures, self-leveling composition Alfa-Pol C, Quick-hardening floor (“Prospectors”), SV-210 floor mixture (Bolars), etc.

As self-levelling compositions known dry mixes for self-leveling floors: Flissestrich FE 80, Flissestrich FE 50, Flissestrich FE 25, which are produced by Knauf enterprises. The hardened solutions from these mixtures have high strength and practically do not shrink.

The main physical and technical characteristics of some types of gypsum leveling mixtures for flooring are as follows:

bulk density, kg / m 3 - 600 ... 700;

water-solid ratio - 0.48...0.6;

solution processing time, min. - 60...120;

the density of the hardened solution, kg / m 3 - 1100 ... 1800;

compressive strength, MPa - 4...10;

tensile strength in bending, MPa-2.5,.,5;

adhesion strength, MPa - 0.3 ... 0.5;

storage period, months - 3...6

Raw materials

For the manufacture of SGS, the following basic materials and additives are used: gypsum binders grades G4-G7 according to GOST 125-79 (for plaster and putty mixtures in the production of finishing works):

high-strength gypsum grade not lower than I 3 according to GOST 125-79 (for high-strength putties and compositions for installation work, as well as in compositions for self-leveling floor screeds); waterproof gypsum binders according to TU 21 -0284757-1-90 (for dry gypsum mixtures used in rooms with wet and wet operating conditions, as well as for floor mixtures); anhydrite binders (from natural raw materials and industrial waste) according to TU21-0284747-1-90 (for plaster mixtures and leveling mixtures for flooring);

hydrated lime according to GOST 9179-77 (residue on sieve 02 up to 0.2% by weight). Humidity up to 0.5% by weight (in plaster compositions and in compositions of self-leveling mixtures for flooring).

Aggregates and fillers have a great influence on the properties of GHS. The choice of aggregate grain size is determined by the type of gypsum mixture: quartz and limestone sand are used with a fineness of up to 0.8 - 1.0 mm. When selecting aggregates, special attention is paid to the granulometric composition: there should be approximately the same ratio of aggregate fractions.

The GHS uses the following aggregates and fillers:

expanded perlite sand according to GOST 10832-91; residue on a sieve with a mesh size of 1.25 mm - less than 10% by weight. Bulk density - from 70 to 125 kg/m3; used in compositions of heat-insulating or lightweight plaster mixtures;

expanded vermiculite sand according to the current NTD;

quartz sands according to GOST 21 38-91, the residue on sieve No. 05 is less than 10% by weight. Moisture less than 0.5% by weight; used in the composition of plaster mixtures and in the composition of leveling mixtures for flooring;

mineral powder for asphalt concrete mixtures according to GOST 16557-78, the residue on sieve No. 0315 is less than 10% by weight. Humidity is not more than 0.5% by weight; used in the composition of plaster and putty mixtures.

Chemical additives for gypsum mixtures must meet the requirements of GOST 24211-91. These include the following additives:

water-retaining based on cellulose ethers (methylcellulose brand MC-100 (Russia); ethyloxyethylcellulose, EOEC (Sweden); sodium salt of carboxymethylcellulose, (CMC), (Russia).

Based on cellulose esters (methylhydroxyethylcellulose, (MHEC), (Germany, USA); methylhydroxypropylcellulose (MHPC), (South Korea);

air-entraining anionic surfactants (Russia, Germany); olefin sulfonate (Germany);

thickening based on starch ether (Russia, Germany); based on hectorite clays (Italy);

plasticizing naphthalene-formaldehyde, for example C-3 (Russia); melamine-formaldehyde (Germany); polycarboxylate (Germany);

redispersion polymer powders: based on vinyl acetate copolymers (Germany, Switzerland, USA, France); based on styrene-butadiene latex (Germany); based on acrylate (Germany);

defoamers- additives, which are hydrocarbons and polyglycols on an inert carrier (amorphous silica).

In the manufacture of CGS, the correct choice of additives that regulate the beginning and end of setting, especially those intended for plastering, is of great importance. In this case, it is necessary to take into account not only the type of gypsum binder, but also the pH environment of the prepared gypsum mortar.

For a neutral environment of a gypsum mortar, citric acid, sodium citrate, polyphosphates, protein hydrolysates, gelatins - CMC (sodium salt of carboxymethyl cellulose), adhesives of animal origin, a mixture of lignosulfonates can be effective setting retarders. However, it should be borne in mind, for example, that retardane, being an active gypsum setting retarder, is very well suited for putty compositions. At the same time, for plaster compositions, it is not effective enough, because. gives a short period between the beginning and the end of setting, which is undesirable in the production of plaster work.

For gypsum mortars with an alkaline environment, tartaric acid, as well as a retarder based on tartaric acid and plastretard, are effective retarders.

For a slightly acidic environment, for example, in plaster mortars based on a gypsum binder of phosphogypsum, hydrated lime and sodium tripolyphosphate are used as a retarder.

To achieve the required delay in the setting of the gypsum mortar, it is advisable to use a complex additive. A typical example is pla-stretard - a mixture of citric acid with polyphosphates and gelatin.

To reduce cracking and shrinkage deformations, cellulose fibers are introduced.

Putty, grout mixtures and gypsum adhesives differ from plaster compositions, both in their component composition and in its dispersion. A feature of these compositions is that building gypsum with a particle size of less than 0.1 mm is used as a binder, the filler is limestone, dolomite flour, chalk with a grain size of less than 0.1 mm. In this regard, the number of water-retaining additives increases to 0.5-0.8%, while in plaster compositions - 0.16-0.3%.

Of great importance in SSS, including SGS, are water-retaining additives based on cellulose ethers. Studies have shown that due to the weak intermolecular interaction with water molecules, these polymers have excellent water-holding capacity. Each polymer molecule can hold up to 20,000 water molecules. The energy of this interaction is comparable to the energy of evaporation and capillary diffusion into the substrate, which is an obstacle to the escape of water. In turn, this energy is somewhat less than the diffusion energy of water during cement hydration, which allows it to take this water.

In fact, the water in the solution is replaced by a homogeneous jelly-like solution of methylcellulose, in which particles of cement and aggregate are suspended. The high water-retaining capacity of such a system contributes to the complete hydration of the cement and allows the mortar to gain the required strength even with thin-layer application. After leaving the water, the polymer in the form of the thinnest film remains on the surfaces between the cement stone and the filler, without affecting the mechanical characteristics of the hardened mortar. Thus, the addition of a small amount (0.02-0.07%) of water-soluble cellulose ethers to cement-sand mixtures leads to a significant increase in open time and allows the solution to hydrate evenly throughout the volume, and also provides a significant increase in adhesion to the base and improvement surface quality. Similarly, the action of methylcellulose in gypsum mixtures.

Dispersion powders, which, unlike water-soluble cellulose derivatives, do not form solutions when mixed with water, but two-phase systems consisting of polymer particles (based on copolymers of vinyl acetate and ethylene, vinyl chloride, styrene acrylate, etc.) dispersed in water . The addition of these compositions to construction chemicals allows you to actively influence the characteristics of the final material and provides results that are unattainable using only traditional mineral binders. The first attempts to modify cement mixtures with polymers consisted of adding a vinyl acetate dispersion, known as PVA glue, to the mixing water. In gypsum mortars, this application turned out to be very effective, while in cement mortars (due to increased shrinkage from the use of PVA) they were quickly abandoned. The next step was the use of two-component compositions consisting of a cement-sand mixture prepared at the factory and a polymer dispersion supplied in liquid form, which are mixed at the construction site. Two-component solutions are still used, but the aqueous dispersion loses its properties when it freezes, therefore, in the cold season, its transportation and preparation of the working solution cause certain difficulties. The beginning of the production of one-component dry building mixtures dates back to 1953, when the specialists of the Wacker company (Germany) managed to obtain a dry redispersible powder, which, after mixing with water, forms a two-phase system that has the properties of the original polymer dispersion.

Dispersions differ from methylcellulose in their mechanism of action. As water is consumed, it concentrates in the pores of the cement stone and the dispersion is concentrated there, forming "elastic bridges" that work in tension and bending incomparably better than cement. The combination of mineral and polymeric binders makes it possible to produce building chemistry products that have not only increased strength properties and improved adhesion (including to such “problematic” substrates as metal, wood, plastic, glazed tiles, etc.), but and controlled rheological (thixotropy, plasticity) and special (hydrophobicity, fluidity) characteristics. For example, leveling mortars for floors contain a combination of special dispersion additives with organic and synthetic plasticizers, the presence of which determines such specific properties of these materials as the ability to spread and the smoothness of the resulting surface. Dispersion modifiers, which are part of adhesive compositions for tile work, improve working conditions, prolong the “lifetime” of the closed solution and increase the thixotropy (the ability to thicken at rest and liquefy when mixed) of the material. They help increase adhesion to complex substrates.

The development of dry mix formulations is a complex and lengthy process that requires the participation of qualified personnel and the obligatory availability of a modern laboratory for research and testing samples of solutions from dry mixes, equipped with modern equipment.

State Unitary Enterprise "NIIMosstroy" develops the formulation of gypsum dry mixes according to the orders of enterprises, tests all types of dry building mixes, including certification ones. To this end, the laboratories of the institute are equipped with modern instruments and equipment, incl. for testing binders according to European standards. Besides. Certification Center NIIMosstroy certifies products and quality management systems.

Dry mortar is a multi-component dry powder, which, when diluted with water, turns into a plastic solution for the desired purpose. Gypsum-based mixtures are lightweight and easy-to-work compositions. The disadvantages include only the possibility of use only inside dry rooms.

Materials based on gypsum binders are characterized by high heat and sound insulation properties, are fire and fire safe, lightweight, and can be used as decorative elements for architectural solutions for interior decoration. The use of gypsum materials for interior decoration provides a favorable indoor climate due to the ability of the material to "breathe" - it is easy to absorb moisture and give it away. In recent years, new generation materials based on gypsum binders have been developed: composite, modified, with reduced water demand and high performance properties.

The main components of gypsum dry mixes are: gypsum binders, fillers, functional additives. As a binder in gypsum mixtures, building gypsum based on b- or a-calcium sulfate hemihydrate is used. Less often they are used in a mixture with anhydrite (especially for plastering) to ensure the necessary setting time. In the compositions of self-levelling mixtures, high-strength gypsum (a-hemihydrate) and anhydrite are used. The use of these types of gypsum binders in flooring compositions is explained by the requirements for such mixtures and hardened mortars - the necessary vitality and high early strength, providing a short walking time.

Gypsum is a quick-setting and water-absorbing compound. Polymers are introduced into gypsum-based mixtures to reduce water absorption and increase adhesion, as well as inhibitors that slow down the gypsum hardening reaction. Inhibitors include, in particular, food or technical citric acid. If, when mixed with water, 10-20 grams of citric acid is added to 1 kg of gypsum, the gypsum mass will slow down its hardening to 30-40 minutes.

The filler is introduced to prevent cracking during operation, improve manufacturability during application. As aggregates in gypsum mixtures, quartz sand is used, as well as limestone flour, dolomite flour, chalk, and ash. Perlite is used in the compositions of light plasters. Functional additives slow down the setting of the gypsum mixture, increase water retention, mobility, plasticity, adhesion strength, create a special porous structure, and reduce the risk of cracking. Setting retarders provide an increase in the survivability of the mortar gypsum mixture. It is known that gypsum binders set quickly, and the solution to the problem of increasing survivability lies in the correct choice of special additives - setting retarders. Water-retaining additives are introduced into gypsum mixtures in order to increase water retention, adhesion to the base, improve mixing, and impart viscosity and plasticity to the mortar mixture. Dispersants (plasticizers) - additives that are absorbed on the surface of the particles of the mortar mixture, reducing the formation of lumps during its preparation. Pore formers are additives used in plaster mixtures to create a special pore structure of the hardened material.

Gypsum mixes are divided into gypsum putties, gypsum plasters, grout mixes, gypsum-based mounting adhesives, and gypsum floor mixes.

Gypsum putties consist of a gypsum binder (we will call it gypsum, although a mixture of alpha gypsum and anhydride is used in the production), quartz or lime filler, a cellulose thickener and a redispersible polymer. Gypsum putties are applied with a layer of 1 mm to 1 cm. Gypsum putties are distinguished by high plasticity and whiteness. Used for plastering walls and ceilings inside dry rooms, with an improved and high-quality finish in the final application. Gypsum-based compositions are especially common today.

When working with gypsum mixtures, you need to know that gypsum is calcium sulfate. When painting a surface leveled with such a mixture, it is necessary to use acid-resistant paints. Do not forget about safety precautions: gypsum, even in a small wound, causes discomfort.

Gypsum plasters- dry mixes, which have gained particular popularity among builders. Mixtures are light, easy to use, do not shrink (unlike lime-cement-sand putties), quickly harden and have high performance - from 30 minutes to 1 hour. Dry plaster mixtures based on gypsum are designed for plastering walls and ceilings with various surfaces indoors with normal and high humidity (kitchens and bathrooms).

Simple gypsum plaster can be prepared independently. The composition (10 kg of gypsum, 1 kg of slaked lime, 50 g of citric acid) is mixed with water and mixed until the consistency of thick sour cream.

With the finished mixture, you can close up the strobes, level the walls or ceiling. Industrial plasters also contain fractionated sand, a cellulose thickener and a redispersible polymer. To give the plaster lightness and volume, light weightless sands are added to the compositions - expanded perlite or vermiculite. The average consumption of such plaster is 7 kg / sq.m when applied with a layer of 1 cm.

Gypsum-based mounting adhesives. Of particular interest are dry gypsum mixes for installation work, which are used for gluing sheet and tile materials (drywall, mineral insulation, foam sheets). The composition is similar to the composition of tile adhesive, only gypsum, not cement, is used as the main component.

Gypsum mixes for a floor. This group includes self-leveling (self-leveling) compositions for pouring floors in various layers. Dry mixes for self-leveling floors have a more complex composition and include such functional additives as superplasticizers, hardening accelerators, defoamers. Gypsum-based compounds are mainly used for indoor screeds.

Among all existing dry building mixes, the most demanded among buyers and builders is a gypsum mix, the price of which is low, but the quality is high. This is due to its characteristics and properties. Which ones, we will consider in the following sections. We will also introduce you to the types of gypsum mixtures and the features of their application.

The composition of gypsum mixtures

The main component of all gypsum mixtures is gypsum powder, which acts as a binder. They also include various additives that are needed for:

improving the quality of work;
prolonging the setting time of the solution;
increase adhesion;
strength improvements;
protection against fungus and mold.

Fine-grained sand acts as a filler. As you can see, the raw materials are mostly natural. This is definitely a big plus.

Types of gypsum mixtures

Dry gypsum mix, depending on the properties and purpose of use, is divided into three kinds:

plaster putty;
gypsum plaster;
gypsum-based glue.

Each of them has its own scope. Dry gypsum plaster mixture is divided into several subtypes. According to the method of application, it can be manual or machine. By scope - starting and finishing. Also putty mixtures are divided into the last two subtypes.

Characteristics of gypsum mixtures

All gypsum mixtures have the following characteristics:

they are white;
mixtures have good elasticity;
the compositions have good strength;
they are able to absorb and release moisture;
solutions are characterized by good adhesion (adhesion);
have excellent sound and heat insulation;
they do not ignite;
mixtures are environmentally friendly.

Advantages and disadvantages of gypsum mixtures

Like any other building material, dry gypsum mixes have their advantages and disadvantages.

First let's talk about pros.

Gypsum mixtures set quickly and dry within an hour.
The surface is quite smooth, it can even not be further processed.
Walls and ceilings, plastered or puttied with gypsum compounds, can then be pasted over with wallpaper, painted or finished with any other material.
They are easy to work with.

We also see no reason to keep silent about the shortcomings. There are few cons of the material, but still they are.

Gypsum mixtures can only be used in rooms where the humidity does not exceed 60%.
Such compositions are appropriate to use only for internal work.
In the bathroom, gypsum mixture can only be used if it is well ventilated.

Features of the use of gypsum mixtures

Now we will analyze in detail what this or that type of gypsum mixture is used for.

Plaster based on gypsum. A mixture of gypsum plaster is used for plastering walls and ceilings in rooms. It can be applied both manually and by machine. The latter - allows you to perform plastering work more quickly, and the mortar will lie better. In addition, this option allows you to save plaster consumption. Walls finished with gypsum plaster do not crack or mold.

Gypsum putty. It is suitable for finishing concrete and cement bases. Such putty perfectly passes air and is not subject to cracks. The walls finished with it “breathe”, creating a favorable microclimate in the room. It is applied to the walls with a spatula, in a thin layer.

Gypsum adhesive. It is well suited for the installation of gypsum boards (gypsum boards), gypsum tongue-and-groove boards (GWP) and other gypsum products. We remind you that, like other gypsum-based mixtures, they can only be used in rooms with a normal humidity regime. Before using such glue, the surface must be thoroughly cleaned from dust and dirt. The entire area to which the adhesive mixture will be applied must be covered with a primer. Only after 12 hours after that, you can start gluing.

How to prepare a gypsum mix?

Since all gypsum-based dry mixes have a powdery structure, they are prepared as follows:

First you need to take a container with a volume of 20 - 25 liters.
Then pour the contents of the package (mixture) into it.
After filling the composition with water.
In the end, everything must be thoroughly mixed until smooth, so that all the lumps disperse.

That's basically the whole process. But only there are some nuances. For example, you can not overdo it with the amount of liquid. The solution will become unusable. Therefore, you should pay attention to the recommendations placed on the package, where all proportions are indicated. Depending on the type of mixture, the amount of water for its preparation is different.

What do we offer?

Gross company offers gypsum dry mixes to buy at a bargain price. In our stores you will find products from leading manufacturers on the Russian market. We always have a large assortment of dry gypsum mixes and other materials for construction and repair. Our prices are the most affordable in the region. Contact us and see for yourself!

If you need to level the surface of the walls in the room or update the facade of the house, wall plastering is one of the most inexpensive and popular ways. Of course, getting started, you must first familiarize yourself with the types of plaster (especially in the case when there is not enough experience in repair work), because choosing the wrong mixture can ruin the final result. In this article, we will tell you how to prepare a cement-based plaster mixture and dry gypsum plaster, as well as which type is suitable for walls.

Wall plaster

Let's compare cement-sand, lime and gypsum mortar for plastering walls according to their characteristics.

Gypsum plaster

The most popular now are dry mixes for gypsum-based plaster. Their main advantage is a very simple application process. Such plaster is sold ready-made, you don’t have to mix anything, you just need to dilute it with water in the required proportions.

The most popular plaster mixture is from Knauf-Rotband, Volma Sloy, Forman 10, Founding Gipswell, Prospectors. In terms of quality, they differ little from each other, but some types cannot be used in wet areas.

Separately, it is worth talking about universal mixtures for wall plastering from Knauf-Rotband. The price for a bag of 30 kg is 360-390 rubles, which is more expensive than all similar options. On sale there is also packing of 5, 10, and 25 kg.

This mixture has been produced for half a century in Germany, and in Russia it appeared 20 years ago. It has become so popular that the name "Rotband" is used by some to refer to any dry gypsum plaster mixes.

There are other gypsum plasters from Knauf-Goldband and HP START, but they are not in demand due to their high density.

"Rotband" has the following characteristics:

Consumption 8.5 kg/sq. m. with a layer of 1 cm. One standard bag is enough to level 3.5 sq. m.
The maximum layer thickness is 5 cm (only 1.5 cm on the ceiling, and if the height differences are greater, then alignment is done using).
The minimum layer thickness is 0.5 cm (1 cm when laying tiles).
The average drying time is 7 days, depending on humidity and thickness.
Suitable for plastering walls and ceilings made of concrete, brick, polystyrene foam surfaces.
This mixture is not suitable for sealing joints between drywall sheets. For this, gypsum-based putty is used - Knauf Uniflot. Read more about in our article.
It is recommended to use in rooms with normal air humidity, it can be used in the kitchen or in the bathroom.
Color - from white to gray or even pink. It depends on the amount of natural impurities, and does not affect the characteristics of the material.
Shelf life - 6 months.

You can apply a thicker layer on the walls after the first layer of maximum thickness has completely dried. On the ceiling, applying more than one layer of plaster is unacceptable.

Among the main advantages of the mixture "Rotband" are the following.

Getting a smooth surface.
The absence of cracks even on a thick layer of plaster (subject to compliance with the technology).
The consumption of the mixture is two times less than that of cement-sand types.
Possibility of applying a layer up to 5 cm in one go without splashing the surface.
The solution does not lose all moisture even on porous substrates or at elevated temperatures, which ensures uniform drying without delamination and without cracking.
The composition does not contain harmful substances, it is completely safe.
Due to the addition of polymer additives to the composition, the mixture provides enhanced adhesion, which allows it to be used even on the ceiling.
The composition of the mixture includes special additives to increase the working time with gypsum mortar.

To obtain the optimal consistency, the dry mixture is mixed with water in proportions of approximately 2: 1, i.e. 15-17 liters of water should be used per 30 kg bag. For thorough mixing, use the mixer nozzle on the perforator.
The video shows an example of plastering work using Knauf Rotband:

Cement plaster mixture

The cement-sand mixture for plaster has the following composition:

1 part of cement m-400;
3-5 parts of sand (if the cement is m-500, then you can increase it to 7 parts of sand).

Usually, when cooking, all the elements are added “by eye”. You can use the following instructions.

The preparation of a solution for plastering walls begins with sifting sand. This will require a sieve with cells of about 4 mm; for dry sand, a finer mesh can be used. When the sand is ready, proceed to the manufacture of the solution. To do this, pour 2.5-3 liters of water into a 10-liter bucket.

To make the solution soft and plastic, you can add a little detergent to the water.

Put three parts of cement into the mortar container and mix it thoroughly with a mixer.
While mixing the solution with a mixer, add sand until the container is full. Start stirring the solution at low speed so that the liquid does not splash out.
As a result, the solution should turn out to be a viscous consistency, so that when the mixer is pulled out, a hole of 2-3 cm remains.

One batch is enough for approximately 1.5 square meters of plaster. m. walls. Basically, the consumption of the mixture depends on the thickness of the applied layer, so if you want to avoid overspending the material, then you need to buy the thinnest beacons, from 3 mm.

Dry mix cement based

If there are no plans to mix the solution yourself, you can buy a ready-made mixture in dry form, which is simply diluted with water.

For example, the following types are on sale:

"Vetonit TT";
"Volma Aquasloy";
"Magma";
Plaster and repair putty "CeresitCT 29";
For facades: Knauf Unterputz, Sokelputz, Grunband (with expanded polystyrene granules), IVSIL GROSS.

Cement-lime mixtures

Cement mortar in its pure form is not used so often, because it has poor adhesion and increased cracking. In addition, not everyone has the opportunity to use expensive dry mixes, so lime mortar plaster is a good alternative. This is a very economical version of the mixture, which is convenient to work with due to plasticity.

Also, this option is good for use in private homes due to bactericidal properties - this is an additional protection against fungus. Lime mortar is chosen mainly for rough wall finishing in rooms with normal and low humidity. Unlike cement mortar, a lime-based mixture is well suited for plaster over shingles, as it adheres well to a wood surface.

The disadvantages of this mixture include low grade strength, in contrast to the solution based on Portland cement. But this drawback does not play a special role; compressive strength is not so much important for plaster as a good level of adhesion and plasticity.

Composition of lime mortar for plaster:

1 part cement;
½ part of slaked lime;
5 parts of sand;
300 ml liquid soap.

The mixture turns out to be very elastic and keeps well on the wall; after drying, cracks do not appear on the surface. Liquid soap adds a pleasant smell and increases elasticity.

Cement-lime mortar for plaster can be prepared in another way:

1 part lime sour cream;
2.5 parts of sand;
0.12-0.25 parts of cement (depending on the amount of lime).

It is best to take quicklime and extinguish it yourself. 50 kg will require 13 buckets of water. Please note that lime will increase by 2.5-3 times during slaking, so this work is done in a barrel of the appropriate volume.

This composition will adhere well and keep on the wall, level with the rule and rub well. Plastering costs 250 sq. m. such a mixture will cost about 22,200 rubles. (per material):

3 cubes of sand - 2000 rubles;
quicklime 800 kg - 19,000 rubles;
cement 150 kg - 1200 rubles.

If we compare the costs with the Rotband plaster, then the same area would take 3-4 thousand rubles more.

Dry mix based on lime-cement

You can purchase a ready-made dry mix on a lime-cement basis.
The most popular types are:

"Knauf Sevener" (universal mixture);
"BEST";
“Founding STARTWELL” and “FLYWELL”;

Facade plaster mixes

In private houses, in addition to interior decoration, exterior wall decoration is required. Many owners unknowingly or for the sake of economy plaster facades with the same mixture that was used for interior decoration. It is strongly not recommended to do this, since the external walls require a mixture that can withstand the effects of the environment and not collapse. Below we give a list of good plaster mixes for facades.

Mineral plaster mixes

Mineral mixtures are produced on the basis of cement, therefore, there is a marking on the packaging - “Polymer-cement mixture”. Thanks to such a component as a redispersible powder, these mixtures have high adhesive qualities. Mineral mixtures are sold dry in bags.

mineral plaster
Specifications:

low cost;
resistance to fire;
moisture resistance;
good strength;
high vapor permeability;
long-term operation.

Acrylic-based plaster mixes

Synthetic plaster mixes are made on the basis of acrylic dispersion. Sold already in finished form in a liquid state and do not require additional preparation.

Acrylic plaster
Specifications:

increased resistance to mechanical stress;
moisture resistance;
high adhesion to various surfaces.

silicate plaster mixes

The basis of silicate mixtures is potash liquid glass. Silicate mixtures are produced in liquid form, ready for use. This type of mixture is ideal for finishing walls insulated with mineral wool.

silicate plaster
Specifications:

excellent elasticity;
good water resistance;
good strength.

Silicone plaster mixes

As you can easily guess from the name, the composition of this type of mixture includes an expensive material - silicone. For this reason, silicone mixtures are very expensive, but the price is well compensated by the merits of this material.

silicone plaster
Specifications:

excellent resistance to moisture;
long-term operation;
excellent adhesion;
high elasticity;
easy installation.

We examined the main types of plaster for walls, ceilings and facades. We advise you to carefully study the characteristics of each of them and choose the most suitable option. You can either buy a ready-made mixture, or cook it yourself according to the proportions above.

Gypsum plasters are the name of a group of finishing materials that are used to decorate finishing coatings. Gypsum is hydrophilic, as a result of which it is destroyed by water, so such materials are only suitable for interior surfaces in dry rooms.

The main element of this material, which binds all the others, is gypsum powder. It is made from a natural mineral that undergoes long-term heat treatment and grinding. For the manufacture of plasters, gypsum of various fractions is used, the smaller the grain size of the miner, the higher the quality of the treated surface.

In addition, the composition of gypsum plaster includes a light fine-grained filler of natural or synthetic origin, as well as various polymer additives. The shape and size of the filler grains affect the appearance of the future surface. Also, fillers significantly reduce the consumption of plaster and make the surface more durable. Polymer components increase the elasticity of the material, as well as its adhesion to various bases.

Gypsum powder - the main component of plaster

Gypsum plaster is supplied as a powder mixture in paper bags of various weights. Water is required for its preparation. By adjusting the amount of liquid, it is possible to change the fat content of the plaster, depending on the goals pursued. For finishing alignment on a pre-prepared surface or decorating the finished coating, a liquid solution is prepared that will be well smeared on the wall. To seal cracks, potholes or rough leveling, a denser mixture is prepared.

Gypsum plaster is supplied dry

General information

Below are the average technical characteristics of gypsum plaster, which may vary, depending on the manufacturer and the materials used:

Working temperature range – +5…+30 °С.
The maximum layer thickness without reinforcing mesh is 5 cm.
Dilution proportions: dry gypsum plaster - 1 part, water - 0.5 parts.
The consumption of this material per square meter is 8 kg.
The setting time of the material is 1 hour.
Complete drying of the surface - 3 hours.
Strengthening time - 7 days.
The thermal conductivity of gypsum mixtures is 0.23 W / m * C.

Advantages and disadvantages of plaster

This material is widely used due to its positive properties:

Gypsum plaster mix consists of 95-97% materials of natural origin, which do not emit toxic substances when heated, wet.
After drying, a perfectly even coating of a pleasant shade is obtained, so further finishing with wallpaper, tiles or paint is optional.
High adhesion to almost all surfaces, thanks to which the material does not lag behind the wall.
A relatively small mass makes it convenient to work with the material, and also allows you to finish the ceilings.
The plasticity of the solution makes it easy to stretch it over the surface, which greatly speeds up and facilitates the work.
Gypsum-based plaster does not shrink, so it does not crack.
Vapor permeability provides high-quality ventilation of the wall, thanks to which water will not accumulate under the layer of material.
Gypsum does not support combustion and does not burn, therefore it is an absolutely fireproof substance.

Gypsum plaster allows you to create a perfectly even coating

There are also some disadvantages:

Low moisture resistance, due to which the scope of the material is limited to dry rooms.
Do not cover surfaces with metal parts with gypsum plaster, as the material will constantly absorb moisture, which will lead to corrosion.
High price compared to other types of plaster.
Low mechanical strength.

What does consumption depend on?

The consumption of gypsum plaster per 1 square meter is affected by 2 main factors - the thickness of the layer and the evenness of the walls. With a pre-prepared or simply not very curved surface (blockage no more than 5 mm), the consumption of gypsum plaster is approximately 300 grams with a layer thickness of 1 mm.

Material consumption depends on the evenness of the surface and the thickness of the applied layer.

You can use the following example. Let's say there is a section of a wall with an area of 1 square meter with a blockage of 3 cm. First of all, you need to weigh the surface at three points. In the first blockage 0, in the second - 1.5 cm, in the last - 3 cm. We summarize the obtained values, we get 4.5 cm, divide by the number of values 3, we get 1.5 cm - the average blockage. This is the thickness of the minimum layer for leveling. After that, we multiply the 15 mm layer by 300 grams of the solution required for the 1 mm layer, we get 4.5 kg per square meter. Next, you need to take into account that there will be a decorative layer about 3 mm thick, for it you need another 0.9 kg. The result is 5.4 kg, add 10% for the stock and round up. As a result, for this wall, 6 kg of facade gypsum plaster or a universal mixture will be required.

Preliminary calculation of plaster consumption allows you not to overpay for excess material

Self-preparation of the solution

There are three main types of material that can be made at home:

With sawdust. 4 parts plaster, 1 part sawdust, 1 tile adhesive.
Gypsum-chalk mortar. 1 part gypsum, 3 parts crushed ground chalk, 5% wood glue of the total mass of the mixture.
Lime-gypsum mortar. 1 part gypsum, 1 part lime paste.

The cooking rules are as follows:

Measure portions of the components with special containers.
Mix dry ingredients.
Add a little water and mix with a construction mixer or a drill with a nozzle.
Leave to infuse for 3 minutes, then mix again.

To prepare the solution, you should have a construction mixer or a drill with a special nozzle at hand.

On a note! This instruction is suitable for purchased mixtures and hand-made from dry ingredients. For a lime-gypsum mortar, gypsum is first soaked with water, mixed, and then added to the lime dough.

Preparing walls for plastering

Before roughing the walls with gypsum compositions, the following steps must be carried out:

Remove the old coating and clean the surface of grease stains, dust, wallpaper and paint residues.
Tap the surface with a hammer to reveal weak fragments of the wall and remove them.
Cracks, potholes and chips should be repaired with mounting foam or cement mortar.
Prime the walls 2 times with an interval of 4 hours.

Stages of preparing the surface for applying gypsum plaster

Important! With a large thickness of the applied gypsum mixture, it tends to fall off quickly, so the installation of a reinforcing mesh is required.

Mesh installation:

First of all, markings are applied to the wall - dots every 40 cm.
Drill holes in the marked places and install dowels.
Scissors for metal cut the mesh into fragments of the required area and shape.
Attach the product to the wall and fix it with self-tapping screws.

Installation of a reinforcing mesh is necessary when applying a large layer of plaster

If the mesh is not installed tightly or vibrates when touched, it is necessary to additionally strengthen it with wire by passing it through the cells in the shape of the letter Z.

The procedure for applying gypsum plaster

The prepared solution should be applied in one layer with a thickness of no more than 5 cm without a grid, no more than 8 cm with a grid. A solution is collected on a trowel or spatula and transferred to the surface, after which it is stretched with a trowel or spatula. Then you need to take the rule and level the material. To do this, the tool is applied to the bottom of the wall and held up, while making zigzag movements.

Should know! The application of gypsum plaster that has remained on the blade of the rule is not possible, as it dries very quickly.

1 hour after applying the solution to the entire wall, it is necessary to treat the surface with a trapezoidal rule. Then all the irregularities are puttied and smoothed out with a wide spatula. Traces of the rule can also be smoothed out with a spatula. The next procedure should be started in about half an hour. But if the surface is pressed through with a finger, then you need to wait a little more time.

The procedure is as follows:

The surface is abundantly moistened with water.
Wait until the wall becomes matte.
They take a sponge grater, press it against the wall and carry out circular movements.
Smooth the entire coating with a wide spatula.
Wait 5-7 hours and repeat the procedure.

Surfaces plastered in this way do not require subsequent filling.

This can be considered the application of plaster completed. Additional procedures are no longer required, but there is a need to provide comfortable conditions for the solution to dry. There should be no drafts and working heaters in the room. In addition, the coating should be protected from direct sunlight. After 3 days, it is necessary to ventilate the room to remove excess moisture. Temperature regime - + 5 ... + 25 degrees.

How to apply plaster with a machine

In the modern construction market, you can find equipment such as plastering machines. It should be noted right away that it is quite expensive, so for one-time or short-term use it is better to rent it. The device consists of a container into which the finished solution or components for it are loaded, a supply hose, a nozzle to control the intensity of the material supply. There is also a power cable, a compressor and a tuning panel.

Machine method for applying gypsum plaster

The procedure for applying plaster:

Load the prepared mixture into a container.
Connect the equipment to the network and pick up the supply hose.
Direct it to the wall, while holding it 30 cm from the surface to be treated.
Turn on the supply of plaster and move from the bottom up.
The layers of material must overlap each other.
At the end, the material is leveled and overwritten in the same way as in the case of the usual application option.

How long does gypsum plaster dry

In a well-ventilated area, subject to the temperature regime, complete drying and curing of the material occurs in 7-14 days. After complete drying, the coating acquires an even light color. At this stage, you can proceed to further finishing. If a tile has been chosen, then you can simply apply glue and mount it. If painting is planned, then the humidity of the wall can be no more than 1%.

Complete drying of the plastered surface occurs in 7-14 days

Important! Accelerating the drying of coatings with the help of heating devices is prohibited.

Basic requirements for the quality of gypsum plaster

The main requirement is a perfectly flat surface without cracks, chips, dents and potholes. This is quite simple to achieve - it is enough to make the mortar correctly and dry the walls. If the color of the wall after drying became uneven, it means that slightly different solutions were prepared. To correct this mistake, you will have to apply a thin decorative layer again, which will smooth out the color.

The formation of cracks in the plaster indicates an improperly prepared mortar or forced drying of the finished surface.

The surface should contain hardly noticeable pores, if there are none, then the vapor permeability will be lower than required by the technology. If the pores are too large, then the solution was poorly mixed. You can fix this with a layer of decorative plaster.

On a note! It is impossible to evaluate the quality of coverage in poor lighting.

It is very easy to prepare and apply this material. It is enough just to observe the composition of gypsum plasters, as well as carefully read the description of the material and its technical characteristics, which are indicated by the manufacturer.

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