Gypsum-based building plaster mix. Technological features of dry building mixtures based on gypsum. But still, gypsum has much more advantages.

During repair work in any room, plastering is an indispensable process that requires compliance with GOST.

Gypsum plaster

To date, there is a huge variety of mixtures in composition and binder that can be selected for certain jobs and surfaces.

To give evenness and smoothness of the surface, as well as for the final preparation of the walls for decoration, it is customary to use gypsum mass, the use of which is allowed even in the bathroom. The following requirements are put forward for this substance:

elasticity;
good adhesion;
having astringent properties.

It is compliance with such requirements that will allow us to answer the question: “Which gypsum plaster is better?”.

The composition and characteristics of gypsum plaster

The main component in the composition of gypsum plaster is gypsum. For the processing of premises, this material has been used for many years, since the mass is quite cheap.

In addition to the main component, according to GOST, the composition includes various fillers and modifying binder additives from polymers.

Due to their binder structure and composition, gypsum mortars can reduce the cost of the mortar, giving it greater elasticity. In turn, polymer additives impart impermeability to the substance, as well as increase adhesion to the treated wall.

This substance is made according to GOST in the form of a dry powder. In order to dilute it for further use, it is necessary to observe a proportional ratio of dry powder and water. The density of the mortar depends on the type of work and in which room the finishing is planned. If you need to level the walls in the room, a thinner solution should be diluted, it will be easier to spread over the surface and easier to apply in a thin layer. To eliminate the curvature of structures, you need a thicker consistency that will hold its shape well.

The universal composition and technical characteristics of the mixture allow it to be used by hand, both for preparatory work and for finishing the premises.

Advantages and disadvantages of the mixture

Today, the alignment of walls with gypsum plaster is used quite often. Gypsum mixture has found its wide application in interior finishing works and has the following advantages:

the composition includes natural components, which makes the mixture environmentally friendly;
smooth and uniform texture allows you to achieve maximum evenness of the surface;
high level of adhesion;
low specific gravity;
good material for heat and sound insulation;
thanks to the binder, it is plastic;
the material is easy to apply;
does not shrink;
breathes easily and lets air into the room;
the mixture can act as a finish coating;
fireproof;
economical application.

Like any other finishing materials, gypsum mixtures have certain disadvantages that you should pay attention to:

the mixture is not moisture resistant (it is better not to use it in the bathroom and other wet areas);
it is necessary to isolate metal objects from contact with gypsum plaster;
high price category;
easily amenable to mechanical stress.

If the composition was made in accordance with GOST, and its application was correct, such a coating will hide any irregularities and create a perfect flat surface.

Do-it-yourself work sequence

Before you start the plastering process, you need to determine the amount of material that you need to finish the room.

As we said, the consumption of gypsum plaster is less than cement, therefore, for work you will need 2.5-3 times less material.

To apply a solution with a thickness of 10 mm, you need ≈9 kg of dry matter per 1 m 2. But, remember, if the walls in the room are especially uneven and have certain defects, much more material will be used to seal and level them.

To apply gypsum plaster, you need to prepare the walls as best as possible. They must be cleaned of old materials and dirt with a soft brush and treated with a primer.

Next, according to the instructions, you need to knead the solution. The composition should turn out to be homogeneous, and not everyone succeeds in achieving this with their own hands. For such purposes, you can use a construction mixer. The resulting solution is best left for a few minutes to gain strength, after which you can start plastering the walls.

To achieve maximum adhesion, it is better to throw a gypsum solution on the surface, and you need to distribute the mass from the bottom up with a trowel or rule. If the walls in the room are too deformed, you can’t do it with your own hands and a trowel, it’s better to use beacons.

In the event that the surface needs to be plastered too thick, you will need a reinforcing mesh.

The gypsum composition hardens within 45-60 minutes, so during this period of time you will need to use up the entire finished mixture.

On the surface, the mixture sets after 1-3 hours, it all depends on the climate in the room.

It is at this stage, after wetting the walls with water, that the surface is grouted with a sponge float.

Are you interested in how long gypsum plaster dries? After 5-7 days from the moment of applying the mixture, the surface will finally dry out, and it will be possible to continue the next finishing work.

What gypsum-based mixtures are the most popular?

Wall decoration in the house with gypsum plaster

Today in the construction market there are a huge number of companies that produce plaster mixes. They differ in composition, characteristics, binder, etc.

It is impossible to say which company produces the most ideal “product”, because the technical characteristics of any gypsum mixture must comply with certain standards that are responsible for the result of the finished substance - GOST.

Volma

This manufacturer has tried to develop a material that is designed for both do-it-yourself work and machine finishing. According to GOST, the material is presented in white and gray. Decorators, on the other hand, focus on a variety of colors, thanks to which the plaster of this brand makes it easy to create relief paintings that retain their shape well and for a long time.

Rotband from Knauf

This company has long taken a leading position in the building materials market. Gypsum plaster from Knauf is another proof of this, although it does not differ in its cheapness. Thanks to this gypsum plaster, with your own hands you will carry out the finishing at the highest level.

Prospectors

The manufacturer "Starateli" took care of the production of plaster according to GOST in several variations, which have a variety of technical characteristics: dry mix, moisture resistant, etc.

Such gypsum plaster hardens very quickly and becomes unsuitable for subsequent use.

A more detailed comparative description of these three representatives is shown in the table.

No matter how high-quality gypsum plaster is, mixtures based on this ingredient have a short shelf life - no more than half a year. To preserve the technical characteristics, the mixture must be dry and in the package without damage.

Tiles and gypsum plaster in the bathroom: is it possible to combine?

When answering the question “Is it possible to lay tiles on gypsum plaster?”, It is better to give a positive answer. But, it is also worth considering certain subtleties of this process, because the cement plaster familiar to such work has a long list of distinguishing features from gypsum.

In the bathroom, shower or other wet areas, the coating should be special, and preferably cement-based. Also for the bathroom, you can use a dry gypsum plaster mass with a special binder.

For wet rooms and bathrooms, the material must comply with GOST and be resistant to high humidity. It is better that the composition of the plaster includes astringent additives, which will give excellent performance features.

Every day, the use of tiles in the bathroom fades further into the background, because gypsum-based dry plaster for processing wet rooms is a more budgetary and original option.

What is plaster grinding? Work performance technology Plaster for the bathroom: features of work in wet rooms

It must meet very different requirements, sometimes almost opposite: high vapor permeability and insensitivity to water, for example. No less controversial is the desire to obtain material with low consumption and very high hiding power. However, gypsum plasters can also fulfill this condition.

- a typical sedimentary mineral based on calcium sulfate. From the point of view of finishing, the material on its base is attractive in that it creates a surface of perfect white color. No additional putty or painting under light wallpaper, for example, is required. However, these are not all the distinguishing features of the material.

The fundamental difference between decorative and leveling plasters is in the setting speed, or, more precisely, in the time until the layer remains plastic. For leveling plaster, it is desirable to reduce this period to a minimum, but for the decorative version, the opposite is true: as long as the layer retains plasticity, it can be processed with special tools to achieve a decorative effect.

Gypsum is quite suitable for both purposes, but only in the presence of polymer additives, which regulate the period of plasticity and setting time. In this case, the filler can be different, but only fine textured.

Advantages

Material advantages:

Gypsum plaster is very plastic, even the usual one for leveling walls can be smoothed to a glossy sheen. Gypsum-based modulating is the best material for creating not just complex reliefs, but relief images.
Gypsum plaster can be applied both manually and by machine: the modifiers added to the mixture regulate the mobility of the solution over a very wide range.
The superb white color is the ideal base for any kind of decoration: painting, shaping.
Do-it-yourself gypsum plaster can include many additional components that noticeably change properties. So, the additive allows you to apply the mortar on concrete walls with the same ease as conventional lime mixtures. And the addition of perlite significantly enhances the thermal insulation properties of the plaster: such a composition is recommended for finishing concrete walls, since the thermal conductivity of the latter is unpleasantly high and the walls feel cold to the touch.
Vapor permeability makes it possible to classify gypsum-based finishes as the most environmentally friendly and safe coatings.
Increased hygroscopicity can be not only a disadvantage: when poured from above, for example, a water stain, provided that the latter was clean, will disappear on its own in 2-3 days. The material not only absorbs, but also releases moisture when it is in excess.
The consumption of the solution is 1.5 times less than that of the most economical.

Flaws

Disadvantages of gypsum plaster:

An obvious important disadvantage is its high hygroscopicity. The material absorbs moisture, and therefore is not used either for external work or for decorating rooms where high humidity is provided - for bathrooms and kitchens, for example.
However, the Rotband website has information about the types of gypsum plaster that can withstand dampness, but in the absence of direct contact with water. That is, for the bathroom, this option is still not good.
For the same reason, gypsum-based decorative plasters are not washable. Maximum - dry cleaning and the use of a barely damp cloth when severe contamination appears.
Gypsum finish does not differ in mechanical strength: you should not use sharp tools to check its integrity.
The hardening time for gypsum plaster is too short - 50 minutes in a container before hardening. Considering that during this time it is necessary not only to apply a layer, but also to create a decorative surface, it is necessary to prepare the solution in small portions, which somewhat complicates the work.

Scope of use

The area of use of GSh is determined by its properties and composition.

Living quarters - due to the high vapor permeability and environmental friendliness, it is this finish that is recommended for the nursery. On the other hand, she does not wash, so the decision of this issue depends on the owner of the apartment. In the living room or bedroom, the material is used without restrictions.
Even the most "water-resistant" option does not tolerate direct contact with water. And if certain varieties can be used for the kitchen, then not for the bathroom.
Gypsum leveling compounds are an excellent base for other finishes. And they are still in demand when it is necessary to create a truly snow-white surface of a wall or ceiling. The thickness of the layer can vary from 5 to 50 mm, with reinforcement - up to 70 mm. The material sets within 80–150 minutes, and dries completely in 5–7 days.
GSH is applied to a brick wall, and even a metal surface if it is protected by an anti-corrosion agent. When finishing surfaces with high porosity - gypsum fiber, you should use a special primer. GSh is not applied to wooden surfaces: adhesion is low.
Modeling plasters based on gypsum are used to decorate only residential premises. Images and ornaments are created in the usual way for this kind of plaster - with a stamp, a roller with a relief surface or the movement of a trowel.

Solution and its preparation

Despite the simple composition, it is recommended to work with a ready-made gypsum mixture, since polymer additives added under production conditions significantly improve the properties of the finish. At home, such a uniform distribution of the substance cannot be achieved.

Composition and structure

The usual composition of the mixture:

gypsum;
fine fraction filler - with grain up to 1.5 mm;
additional additives.

This limitation - fine fraction, reduces the number of decorative options. In fact, only modeling plasters are obtained on the basis of gypsum. Leveling compounds are much more popular.

The solution, as already mentioned, is prepared in small portions. After 50 minutes, the mixture completely solidifies. 25-30 minutes - the period of sufficient plasticity of the material.

And now we will analyze the composition, proportions and recipe of gypsum plaster.

From this video you will learn about the technology of applying gypsum plaster on lighthouses:

Recipes

With sawdust

There are quite a few recipes for preparing the mixture - we mean leveling types:

1 volume fraction of a mixture of Rotband or Ecogypsum;
1 share of crushed sawdust;
3-4 shares.

The dry ingredients are mixed, and then added in small portions to the water.

The composition has good sound and heat insulation qualities.

Gypsum-chalk

Gypsum-chalk plaster is more suitable for finishing, it is prepared as follows:

crushed chalk - 3 kg;
gypsum - 1 kg;
5% wood glue solution.

Gypsum and chalk are mixed, and then wood glue is added to the container with the ingredients until a pasty mass is obtained. Since the solution sets quickly - there are no modifiers here, then it should be prepared from a dry mixture little by little.

Lime-gypsum

Lime-gypsum plasters for interior decoration are even more popular: they set more slowly and better tolerate mechanical stress.

The composition is:

water is added to 1 part of gypsum with stirring until a gypsum dough is obtained;
3 shares of lime are dissolved in water;
then the solutions are thoroughly mixed.

From ready mix

A dry mixture of gypsum plaster is poured into a container with water at the rate of 0.5–0.7 liters per 1 kg of the mixture, mixed until smooth. You can mix both manually and with the mixer attachment on a drill.
The solution should stand for 3-5 minutes, then it is mixed again and used.

It is impossible to dilute the composition with water again. Next, the technology of applying gypsum plaster is considered.

Application technology

So, how to properly plaster walls with gypsum plaster? The solution should be applied within 30 minutes. For this, a trowel or a falcon is used - a square platform on the handle. The latter is often used when working with the ceiling.

The resulting solution can be applied in a layer of 10 to 50 mm, on the ceiling - 30 mm. If a thicker layer is required, then the second one should be applied only after 24 hours.
Align the layer with the rule.
After 45–60 minutes, the GSH layer is smoothed with a metal spatula or processed with a decorative tool.
If the surface is prepared for wallpaper or paint, then after 20 minutes, when the layer is no longer pressed through with a finger, the coating is moistened with water, and when it becomes dull, rubbed with a sponge. The movements are circular. Then the wall is smoothed with a spatula. A day later, this procedure is repeated. So get a smooth surface that does not need putty.
Drafts should be avoided on the first day. The coating dries completely within 5-7 days, after which you can proceed to further finishing.

About the consumption of gypsum plaster per 1 m2, read below.

The video below will tell you about applying gypsum plaster without beacons:

GS consumption

Gypsum plaster is one of the most economical coatings - this means leveling plaster. When forming a layer of 10 mm, the consumption is 10 kg per 1 sq. m.

For comparison, lime leveling plaster needs at least 14-15 kg.

Requirements for the quality of materials

The quality of dry building mixtures based on gypsum binder is regulated by GOST 31376-2008. Mixtures, ready-made mortars and the actual plaster layer are subject to verification.

Dry formulations must meet the following requirements:

grains with a diameter of 5 mm are not included in the mixture. Granules with a diameter of 1.25 mm can be no more than 1.0% by weight, with a diameter of 0.2 mm - no more than 12% and with a diameter of 0.125 mm - no more than 15%;
humidity of the mixture - no more than 0.3% by weight;
the activity of natural radionuclides must comply with the requirements of GOST 30108.

Ready-to-use mixtures must fulfill the following conditions:

setting time with a manual method - 45 minutes;
setting time in machine production - 90 minutes;
the ability to retain water is at least 90%;
the mobility of the mixture must comply with GOST 31376: the diameter of the spread is 165 mm with an error of 5 mm. This indicator can be changed at the request of the customer.

The finished coating must meet the following requirements:

ultimate strength in bending - not less than 1 MPa;
compressive strength - not less than 2 MPa;
adhesion strength - not less than 0.3 MPa.

If necessary, the average density of the plaster layer is also found.

Popular brands and prices

Numerous companies producing materials for building decoration did not ignore gypsum mixtures.

The most famous in our market are gypsum plasters "Rotband" from Knauf (Knauf). It is these compositions that can be used in relatively wet rooms. It can be used for both manual and machine application. The weight of the package is 30 kg, the price of gypsum plaster is from 290 to 355 rubles.
No less popular is the manufacturer of gypsum plaster "Volma". It is a leveling plaster with excellent adhesion for any type of surface except wood. Package weight - 30 kg. Price - from 270 to 355 rubles.
They compete with dry gypsum mixes from Osnovit. Both white and gray gypsum plasters are produced. Package weight - 30 kg, cost - from 260 rubles.
Under the brand name "Prospectors" a variety of building materials are produced, including gypsum plasters, designed for leveling and finishing concrete, brick, and other surfaces. Package price - from 270 to 305 rubles.
Gypsum plaster from Vetonit is designed for both manual and machine application, the cost of a package weighing 20 kg is from 394 rubles.

Gypsum plaster in the vast majority of cases belongs to the category of leveling mixtures. It is ideal for living rooms with low humidity and a stable microclimate.

This video will tell you about the use of Rotband gypsum plaster from Knauf:

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 the consumption of plaster 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.

Dry gypsum mixes are a fairly popular type of finishing materials and are widely represented on the construction market. Popularity is explained by the ideal ratio of price and quality, ease of preparation and use, as well as the wide availability of formulations.

Peculiarities

Dry gypsum mixtures are presented in the form of homogeneous bulk materials, consisting of gypsum binder, fractionated filler, modification additives and pigments. The role of the binder component is building gypsum, which is based on calcium sulfate hemihydrate.

Anhydrite is added to high-quality gypsum for the manufacture of particularly strong mixtures. These two components are responsible for the working qualities of the composition, providing a quick setting and high strength of the material. The brand of gypsum used for the manufacture of dry mixes is regulated by GOST 125 79, which allows changing the strength range of the component from 3 to 7 MPa.

As a fractionated aggregate, limestone and dolomite flour, ash, chalk or quartz sand are used. These components significantly reduce the cost of the composition and help prevent cracking of the hardened mixture during its operation. In the production of light plaster compositions, perlite is often used, and mica is added to putty products. The particle size of the dispersion components depends on the type of mixture and ranges from 0.1 to 1.0 mm.

Modifying additives are introduced into the composition of the material to improve its performance and ease of use. Thus, the addition of hydrated lime Ca (OH) 2, as well as the use of cellulose fibers, significantly increases the plastic properties and mobility of mixtures, provides good adhesion, and also significantly reduces shrinkage deformations and the risk of cracks.

Setting retarders also play an important role. Their use significantly increases the survivability of the mixture, promotes convenient application and makes it possible to correct the formed layer.

If, despite the presence of additives, the gypsum mortar sets too quickly, 10 to 20 grams of citric acid should be added per 1 kg of dry mix. This will slow down the setting of the composition by 30 minutes.

Pros and cons

The high consumer demand for dry gypsum mixtures is due to a number of positive properties of these compositions:

A characteristic feature of gypsum mixtures is the high yield of the finished solution per unit mass of the dry product. This allows you to reduce material consumption by more than two times, in comparison, for example, with cement mortars. So, for plastering one square meter of surface, only 9 kg of gypsum plaster is required, while the consumption of cement for finishing the same area will be about 18 kg.
The high plasticity of the mortars makes the process less complicated and time-consuming, in comparison, for example, with cement compositions.
The uniformity and smoothness of the formed layer allows you to immediately start applying a decorative coating.
No shrinkage.
Excellent adhesive properties allow plastering without the use of reinforcing mesh. The exception is the walls of new buildings, in which movements are possible due to shrinkage of the new building.

High sound and heat insulation properties of dry mixes guarantee reliable protection of premises from cold and extraneous noise.
The small weight of the walls covered with gypsum significantly reduces the load on the supporting structures of the building.
The fast speed of primary setting and complete drying can be attributed to both the advantages and disadvantages of gypsum mixtures. The assessment of this quality depends on how professionally plastering or puttying work is performed, as well as on how quickly it is necessary to complete the installation.
Dry mixtures are environmentally safe and non-flammable, which allows their use in residential premises and public buildings without restrictions.
Gypsum materials are well ventilated and quite hygroscopic. This gives them the opportunity to release accumulated moisture and reduces the risk of mold and mildew on the walls.

The disadvantages of dry mixes of gypsum include the impossibility of their use in outdoor work., as well as in rooms with air humidity above 60%. The rapid setting of the composition can also be attributed to the disadvantages. To avoid premature hardening, dilute the mixture in small portions and use setting retarders, for example, a mixture of citric acid with polyphosphates and gelatin. Another disadvantage is the low strength of the gypsum layer, which can be easily scratched or chipped. The price of gypsum mixtures is usually 15-20% higher than the cost of cement-sand compositions.

Kinds

Dry gypsum mixes are available in several versions, and differ from each other in composition, purpose, place of application and cost.

On the modern market there is a huge selection of plaster, putty, mounting, grouting compounds, as well as self-leveling mixtures and adhesives.

Plaster mixtures are a very common type of dry composition and are used in interior decoration. Gypsum-based plaster is very easy to use: the formed layer is not prone to slipping and cracking, the installation process is very simple and anyone can do it. The average productivity per day can reach 40 square meters of surface, which is a very good indicator and provides a significant reduction in repair times. Among the minuses of plaster, there is a low resistance to moisture, which does not allow work to be carried out on the street. The disadvantages can be added to the low frost-resistant properties of the material, as well as the rapid setting of the finished solution.
Mounting mixtures are used in the construction of internal partitions, during cladding with plasterboard or gypsum-fiber boards, as well as for laying the foundation when laying the floor from GVL. The material also does not tolerate high humidity and is not recommended for use in outdoor work.

Putty mixes are represented by non-water-resistant dispersed compositions and are intended for finishing and leveling the bases, for preparing plastered or concrete walls for painting, for cladding and restoring household items, eliminating butt joints when finishing with GKL and GVL sheets. This light finishing putty has excellent adhesion, does not shrink and dries quickly.
Gypsum-based glue is indispensable if drywall, tongue-and-groove boards and GVL are used during installation. The material has low waterproof performance, so its scope is also limited to dry and warm rooms. To ensure high adhesion and increase the strength of bonding, 12 hours before applying the adhesive, the surface must be thoroughly cleaned of dust and primed. Only in this case, you can count on the reliability of the connection and its durability.

Self-leveling compounds are used as self-leveling floors and are characterized by high strength and smooth surface. The material is easy to prepare and install, does not shrink and dries quickly.
Grout mixtures are represented by finely dispersed compositions and are designed to eliminate minor defects in working bases. The material has good adhesion, high ductility and low cost.

Scope of application

Dry gypsum mixes are widely used in construction and repair. With their help, floors and walls are leveled, tiles are glued, cracks, chips and other base defects are eliminated. Plaster compositions can plaster almost any surface: brickwork and clay walls, concrete bases and cellular foam concrete, gas and expanded clay concrete and an old plastered wall. In addition to repair and construction work, gypsum compositions can also perform a decorative function.

They are actively used in the manufacture of artificial stone, for the design of bottles and cans, for decorating rooms, for creating stucco moldings and bas-reliefs. Mixtures are indispensable in the construction of internal partitions, for the construction of which metal profiles and drywall are used.

With the help of assembly and grout mixtures, it is possible to completely hide the gaps between sheets and achieve a perfectly even and uniform surface.

Manufacturers

Gypsum dry mixes are produced in many countries of the world.

The most famous and recognizable manufacturers are the German concern Knauf and Russian companies "Volma" and "Prospectors". Knauf products account for about a third of the total volume of dry mixes on the domestic market. The company has been known to the Russian consumer since 1993 and produces the entire line of gypsum compounds, including plasters, grouts, masonry mixtures and adhesives. Every year, the company's sales volumes increase by 35%, which indicates the high quality and demand for German products. The production facilities of the company are located in more than 250 countries of the world, the production of mixtures is carried out on high-tech equipment with strict control over the quality of the compositions.

Volma company occupies an honorable second place in the construction market after Knauf, and is engaged in the production of putties, plasters, levelers, tile adhesives, assembly and self-leveling mixtures. The company operates in 5 factories and owns three gypsum quarries. "Prospectors" are also well known to the Russian buyer. The company has four branches, 15 production lines, and is considered the largest producer of dry mixes in our country. No less popular are the products of the Gypsopolymer and Perel companies. Enterprises produce the entire line of gypsum mixtures, which are of high quality and low price.

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 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.

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