Fraction of filler of gypsum plaster mix from. Features of gypsum plasters and the rules for their application

The main components of gypsum dry mixes are: gypsum binders, fillers, functional additives.

Used as a binder in gypsum mixtures building plaster based on calcium sulfate hemihydrate. Less often they are used in a mixture with anhydrite (especially for plastering works) to ensure the required setting time. High-strength (experts say “high-quality”) gypsum and anhydrite are used in the compositions of self-leveling mixtures. The use of these types of gypsum binders in flooring compositions is explained by the special requirements for the strength of such solutions.

The filler is introduced to reduce the cost of the product, but most importantly - to prevent cracking during operation. In addition, its use improves the manufacturability during application. As aggregates in gypsum mixtures, quartz sand is used, as well as limestone flour, dolomite flour, chalk, ash. Perlite is used in the compositions of light plasters - for example, in mixtures such as HYPER PLAST (the name of this mixture comes from a combination of the words Gypsum and PERLITE). In certain types of putty mixtures, the use of mica is recommended. The dispersion of aggregates is determined by the type of gypsum mixture: quartz sand and limestone sand are used with a dispersion 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.

Hydrated lime Ca(OH)2 is added to gypsum mixtures to improve plastic properties, reduce shrinkage and slow setting.

Functional additives slow down the setting speed of the gypsum mixture, increase its water retention, mobility, plasticity, adhesion strength, and reduce the risk of cracking.

Setting retarders are important functional additives that provide an increase in the survivability of the gypsum mortar mixture. It is known that gypsum binders quickly set, and the solution to the problem of increasing survivability is right choice special additives - setting retarders.

Cellulose fibers are introduced into the composition of gypsum mixtures to reduce cracking and shrinkage.

These are the lightest in weight and easy-to-work formulations. Their only drawback is the possibility of use only inside dry rooms.

Gypsum is known to be a fast-setting and hydrophilic (water-absorbing) compound. The same polymers are introduced into the gypsum-based mixture in order to reduce water absorption and increase adhesion (adhesion strength), as well as inhibitors - substances that slow down the gypsum hardening reaction. The simplest example inhibitor - food or technical lemon acid. If, when mixed with water for 1 kg of gypsum, you add 10-20 grams of citric acid, then the gypsum mass will slow down its hardening to 30-40 minutes.

Gypsum mixes subdivided into:

Gypsum putties

They consist of a gypsum binder (hereinafter we will call it gypsum, although a mixture of alpha gypsum and anhydride is used in the production), quartz or limestone filler, cellulose thickener and a redispersible polymer. Gypsum putties can be applied in layers from 1 mm to 1 cm.

Attention! Gypsum is calcium sulfate - CaSO4. When painting a surface leveled with such a mixture, it is necessary to use acid-resistant paints. And, accordingly, observe safety precautions: gypsum, even in a small wound, causes very unpleasant sensations.

Gypsum plasters

Dry mixes that have earned the highest recognition from professional builders. They are light, easy to use, do not shrink (unlike lime-sand-cement putties), quickly harden on the surface and have a fairly high performance - from 30 minutes to 1 hour.

You can make the simplest gypsum plaster in your kitchen: take 10 kg of gypsum, 1 kg of slaked lime, 50 grams of citric acid, mix it all with water and mix until a thick sour cream is obtained.

With the finished mixture, you can close up the strobes, level the wall or ceiling. Although industrially prepared plasters also contain fractionated sand, a cellulose thickener and a redispersible polymer. In some compositions, to give the plaster volume and lightness, expanded perlite or vermiculite is added - light, weightless sands. The average consumption of such a plaster is 7 kg / m2 with an application layer of 1 cm.

Gypsum-based mounting adhesives

If we want to glue a drywall sheet, mineral insulation, a foam sheet to the wall, it is best for us mounting adhesive based on gypsum. The composition is similar to the composition of tile adhesive, with the exception of the main component: instead of cement, gypsum.

Gypsum floor mixes

Self-leveling (self-leveling) compositions for pouring floors in various layers. The composition and principle of action are discussed in the first part of the article (see also the article Leveling the floor).

Putties based on a polymer binder

They differ from the above types of dry mixes in that they do not contain either cement or gypsum. These are fillers, almost 100% consisting of aggregate - fine limestone or marble flour, cellulose thickener and redispersible polymer.

Putties of this type are very convenient in application and subsequent processing (sanding), suitable for subsequent painting or wallpapering. In diluted form, they have a working capacity of up to 24 hours. But these putties are not intended for leveling surfaces for laying tiles. Putties based on a polymer binder are used only inside dry rooms as a finishing layer for leveling the surface and are not used without further coating.

Smooth walls are a guarantee quality repair. And one of the simple and reliable ways to level and decorate walls is to plaster them. In this article, we will analyze in detail all the issues related to gypsum plaster: what is it for, what are its features and technical characteristics, pros and cons, and applications. We will also show you how to work with this material.

The use of gypsum plaster

Plaster mixes based on gypsum are used primarily for finishing walls and ceilings. living rooms, as well as other rooms with normal humidity.

It can be placed on such grounds as:

• brickwork and clay walls;
• over concrete walls and cement plaster (treatment with concrete contact is needed);
• on old gypsum plaster, subject to its good strength;
• on cellular foam concrete, aerated concrete and expanded clay concrete;

Since gypsum is able to absorb moisture, it is used only for interior decoration dry rooms when preparing the surface for painting or wallpapering.

Current prices:

Gypsum plaster

What is included

The main component of this type of plaster is building gypsum - calcium sulfate hydrate obtained by firing gypsum stone and crushed to a powder. The composition can also be added:

• fillers that reduce weight and increase thermal insulation properties light plaster: perlite, vermiculite, foam glass or expanded polystyrene;
• plasticizers and setting retarders;
• additives that increase the whiteness of the surface - salts of various metals (zinc or titanium white) or lime;
• components that increase their strength;
• additives that regulate the setting time of the solution and the time of its hardening.

Gypsum plaster is environmentally friendly clean materials and absolutely not hazardous to health. Moreover, due to its hygroscopicity, it is able to "breathe", that is, absorb excess moisture and, on the contrary, give it away, thus regulating the microclimate in the room.

A separate type of gypsum plaster is gypsum polymer. It is used for leveling brick and concrete surfaces. Gypsum polymer compositions in some cases can also be used for exterior finishing work.

Specifications

The quality of mixtures on gypsum binder is regulated GOST 31377-2008 . According to this document, the main indicators of dry material include:

• humidity: moisture content of not more than 0.30% of the total mass is allowed;
• limiting size of granules (grains);
• volumetric weight: 800-1100 kg/m3 (loose) and 1250-1450 kg/m3 (compacted).

Properties of prepared solutions:

• water consumption during mixing - 0.6-0.65 l / kg
• mobility: the ability to spread under the influence of its own weight; according to GOST 31376, the diameter of the spread sample of the prepared solution (~ 600 g) should not exceed 165 mm (± 5);
• setting time - at least 90 minutes for mixtures of machine application and 45 minutes for manual plastering;
• complete drying time - after 5-7 days; this indicator depends on the additives in the mixture and differs from manufacturer to manufacturer; you can find out exactly how much the plaster dries in the instructions on the package;
• the ability to retain moisture without allowing it to drain: at least 90%;
• consumption with a layer of 10 mm - 8.5-10 kg / m2 (manual application) and 7.5-9 kg / m2 (machine).

Properties of gypsum plaster in hardened form:

• compressive strength - 2.5 MPa;
• adhesion force with the surface - 0.3 MPa;
• density - 950 kg / m3;
• vapor permeability - 0.11-0.14 mg / pchPa;
• thermal conductivity - 0.25-0.3 W / m * C;
• shrinkage - does not shrink

Although vapor permeability (the ability to pass water vapor) of plastered surfaces is not regulated by GOST, it is also important. technical specification, which determines the scope of the plaster.

When purchasing gypsum mixtures, you should pay the most close attention for their expiration date. Due to the ability to easily absorb moisture, they are not stored for more than 6 months from the date of issue. After this period, their properties change, they begin to clump, and quality alignment walls with them becomes problematic. It is also necessary to pay attention to the tightness of the packaging, which protects against excess moisture - you should not buy plaster in torn bags.

Advantages and disadvantages

The main disadvantages of this material are

• Low moisture resistance;
• Low strength - a surface plastered with gypsum can be scratched or chipped quite easily.
• The cost is slightly higher than cement-sand mixture, by about 15-20%, but this is an insignificant minus.

But still, gypsum has much more advantages.

• High plasticity: it is easier to work with gypsum mortar than with others; the complexity of the process is significantly reduced, and this is a significant plus;
• No shrinkage: for cement mixtures, it is a couple of millimeters per square meter;
• Surfaces plastered with gypsum are smoother, without pores and granularity;
• Good adhesion: gypsum mortar adheres to the surface much better than sand-cement; therefore, a reinforcing mesh to strengthen the surface can not be used; it is required only in new buildings due to the possible shrinkage of the building;
• Good heat and soundproofing properties: a wall covered with a layer of gypsum retains heat and protects against noise better than concrete surfaces;
• It can be applied in a thicker layer (up to 50 mm) without reinforcing mesh;
• Light weight: walls covered with gypsum give less load on the foundation;
• Profitability: when comparing the cost, many pay attention only to the weight of the pack; however, it is necessary to take into account specific gravity mixtures - after all, the consumption of gypsum per 1 m2 is 9-10 kg, while cement for plastering the same area will need 16-18 kg.

Expert opinion

Alexander Guryanov

Plasterer and decorator

Many refer to the advantages of gypsum and a higher setting rate than that of a cement-sand mortar. However, it is difficult to call this a significant advantage. Indeed, a surface treated with gypsum plaster hardens 1-1.5 hours faster than a surface coated with a cement composition.

You should not hesitate when working with it - it will be problematic to smooth out the solution that begins to solidify. Don't dilute too much of the mixture if you're working on your own. It is better if one person cooks, and the second plasters.

How to mix dry mix

Consider the preparation process and the proportions of the gypsum solution. The dry mixture from the bag is poured into a prepared container already filled with water. According to the instructions, 600-700 ml of liquid is required per 1 kg, that is, about 20 liters of water will be needed for a 30-kilogram bag of gypsum.

A small amount of mortar can simply be mixed with a trowel or trowel. If it is difficult to make large volumes with your own hands, then it is better to use a perforator with a mixing nozzle or a construction mixer.

The solution should stand for 3-5 minutes (component response time). Then it is again thoroughly mixed until the complete disappearance of all lumps. The solution should turn out to be viscous and plastic, but in no case should it drain from the tool.

Gypsum plasticizers

However, at home, it is quite possible to make gypsum-based mixtures with your own hands, for example, quite plastic lime-gypsum. But the reaction between gypsum and water is quite fast, so gypsum plaster hardens quickly.

To make a solution convenient for work, one of the plasticizers must be added to it:

• diluted pva glue, about 1% of the total;
• lime, used as a plasticizer and to increase the setting time;
• tartaric, citric acid will also slow down the setting. FROM Special fluids such as Plast Retard PE can extend the setting time to several hours, prevent cracking and improve the wear resistance of the gypsum.

Application in wet rooms and outdoors

As we have already mentioned, gypsum plaster is able to absorb moisture, so its use in wet rooms and even more so for facade decoration not desirable.

If it is necessary to make the gypsum surface moisture resistant (for example, in preparation for tiling in the bathroom), it is coated with a deep penetration primer on acrylic base. Concrete contact soil is ideal under the tile.

Polymer also has good moisture-proof properties. waterproofing mastic, for example, Plitonit Hydroelast. It is applied over a carefully dried layer of plaster with a brush or roller in several layers. Each of them must be applied after the previous one has dried. Tile sticker is allowed only one day after application. It is recommended to fill the exit points of pipes and corners of various structures with the same mastic.

How to plaster with gypsum mortar (video)

You can work with gypsum plaster using a plastering station or manually. Machine application is a separate topic for conversation, and we will consider it in another article. And here we will analyze the nuances of manual application.

• the thickness of each layer can be 30-50 mm; if necessary, a new layer can be applied only after the previous one has dried;
• dry mix consumption in the absence of large irregularities with a layer thickness of 1 cm - an average of 9-10 kg / m2;
• gypsum mortar can be applied not only to brick, concrete surfaces and aerated concrete, but also to the previous layer of cement or gypsum plaster;
• surface leveling is carried out using beacon profiles or plaster beacons — a small amount a mixture that is point or line applied to the wall and leveled; after they dry, a solution is thrown between them, and then the entire plaster mass is leveled building rule; the thickness of the layer in this case will be equal to the height of the beacons;
• for dust removal, protection against shedding of small particles and strengthening the surface after plastering, the surface must be primed;
• to obtain a flat surface before painting or gluing thin wallpaper the walls are additionally puttied;

The video below shows all the stages of finishing: how to properly knead, apply and rub.

Grouting and polishing

Grouting is the manual removal of small irregularities, seams, transitions between layers. Usually rubbed after the plaster has dried. To do this, take a metal or plastic grater. The tool is moistened with water or a primer intended for application after plastering, and the surface is treated with circular or vertical and horizontal movements, periodically cleaning the grater from the solution. Special attention give to the corners.

The video above (time 5:35) shows the process of surface glossing - creating a perfect plane without finishing putty. Glossing and rubbing are very similar methods, using the same tools and techniques. But the difference is that this happens on freshly set and still wet plaster. This saves time, and there is no need to apply putty.

Lined wall finishing

After applying a layer of plaster, it is necessary to determine how further finishing will take place:

As you can see, gypsum mixtures are extremely in demand in finishing and repair work and are used everywhere.

We hope that this article was useful to you and that you found the information you are interested in. Please leave your questions and comments in the comments below.

Types of plaster We compare the properties of gypsum and cement plaster: when which one is better to choose, and can it be mixed?

Types of plaster Preparation of cement mortar for plaster: choice of material, proportions, mixing

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 the plaster mixture is prepared on cement base and dry gypsum plaster, as well as which type is suitable for walls.

Wall plaster

Comparative characteristics of plaster mixtures

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 plaster on plaster base. 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.

"Knauf Rotband"

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 (on the ceiling only 1.5 cm, and if the height difference is greater, then alignment is done using suspended ceilings).
• 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 drywall puttying 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 when elevated temperature, which ensures uniform drying without delamination and without cracks.
• The composition does not contain harmful substances, 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 ready mix 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 pure form not used as 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 very economical option a mixture with which it is convenient to work due to its plasticity.

Also, this option is good for use in private homes due to bactericidal properties - this additional protection from 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 plastering on shingles, as it adheres well to a wooden 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 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).

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, it is required exterior finish walls. Many owners unknowingly or for the sake of economy plaster facades with the same mixture that was used for interior decoration. It is strongly discouraged to do this, because for external walls requires a mixture that can withstand exposure environment and yet 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 ready-made liquid state and do not require additional training.

Acrylic plaster
Specifications:

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

silicate plaster mixes

The basis of silicate mixtures is potassium 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 very expensive, but the price is perfectly offset by the advantages 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.

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 paint under light wallpaper, for example, is not required. However, that's not all distinctive features 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 - best material to create 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.
• Excellent White color serves as an ideal base for any decoration: coloring, image formation.
• 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 thermal insulation properties plasters: this 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.

disadvantages

Disadvantages of gypsum plaster:

• An obvious important disadvantage is its high hygroscopicity. The material absorbs moisture, and therefore is not used for any external works, nor for the design of rooms where it is provided high humidity– bathroom and kitchen, 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 decorative plasters on the basis of gypsum are not washed. Maximum - dry cleaning and the use of a barely damp cloth when severe contamination appears.
• Gypsum finish is no different 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 decorative surface, you need to prepare the solution in small portions, which somewhat complicates the work.

Scope of use

The area of ​​use of HS 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, brick wall, and even 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. On the wooden surfaces GSh is not applied: 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 relief surface or the movement of the 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 restriction is a fine fraction, reduces the amount 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.

1. 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.
2. Align the layer with the rule.
3. After 45–60 minutes, the GSH layer is smoothed with a metal spatula or processed with a decorative tool.
4. 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.
5. 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

Dry quality building mixtures on gypsum binder regulates 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 at manual way- 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, also find average density plaster layer.

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 Construction Materials, 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:

Regardless of the type of repair (cosmetic or major), a process such as plastering walls is required. It is safe to say that these works are the most time-consuming and expensive. They cannot be performed without the use of special dry mixes.

There are several types of this finishing material, but the most high-quality, reliable and easy to use are gypsum plaster mixes.

As the name implies, the basis of the material is gypsum.

In addition, it is also possible to distinguish the following main components that make up gypsum plaster:

• Filler. Differs in easy structure and consists of small fractions. The presence of a filler ensures the stability of the form and structure of the plaster. Thanks to this, gypsum plaster mixtures are extremely economical in consumption.
• Polymers. They give the mixture properties such as elasticity and impermeability. In addition, the presence of polymers guarantees a high rate of adhesion of the mixture to the working surface.

The composition of gypsum plaster allows you to use it for such purposes:

• Masking and sealing a variety of defects and irregularities on the surface.
• Formation of slopes and corners (see).
• Alignment of walls that have a littered corner.

Note. Plaster gypsum mixture is produced in the form of a dry powder, packed in convenient and sealed bags.

Main advantages

This is clearly seen in the table below:

Note. From the foregoing, it follows that gypsum plaster mixtures are the most economical and comfortable view dry plaster, the price of which is available to every buyer.

Usage

You can familiarize yourself with the preparation process from the instructions printed on each package.

Stages of work

• First of all, you should pay attention to the temperature inside the room. It should be within + 5 + 30 degrees Celsius.
• Before starting finishing work, it is necessary to prepare the surface: Having cleaned it of dust, old plaster (see How to remove old plaster from walls without problems), dirt.

It is also required to remove all foreign objects:

• Nails.
• Hooks.

Advice. If it is not possible to remove them, they must be treated with a special anti-corrosion liquid.

The surface on which the gypsum plaster mixture will be applied must be treated with a primer:

• If working surface strongly absorbs moisture, for example, aerated concrete or brick, it will have to be coated with a primer several times.
• This is necessary in order to ensure good adhesion of the mixture to the surface.

Now you can start preparing the solution:

• To do this, the powder from the bag is poured into a deep container and poured clean water at the rate of 0.6 - 0.8 l of water per 1 kg of dry powder.

• If such devices are not available, you can interfere manually. I would like to note that the prepared mixture must be used within 30 minutes.
• Otherwise, the solution will begin to dry out and become unsuitable for further use.
• It should also be noted that it is also impossible to allow foreign components to get into the finished plaster.

Note. This can disrupt its composition, which as a result will lead to the fact that it will lose its properties.

The gypsum plaster mixture is applied to the surface with a layer, the thickness of which varies between 50 - 79 mm:

• Work must start from the top down. After a layer of plaster has been laid, it should be leveled.
• To do this, you can use a special tool - a rule that has the shape of the letter h. After an hour, remove excess plaster as a rule.
• You can finally level the plastered surface with a construction spatula with a wide base.

• If no traces remain, it must be abundantly wetted and rubbed with a sponge grater. You need to do this with gentle circular motions.
• To achieve maximum flat surface plaster, after about 24 hours this procedure can be repeated.

Note. One of the advantages of this solution is that plastering with a gypsum mixture eliminates the need for subsequent processing of the working surface.

• For quick and high-quality drying of the solution, it is necessary to completely eliminate the presence of drafts in the room.
• In addition, direct sunlight should also not be allowed to hit the surface.
• The final stage of work is to ventilate the room. Thus, excess moisture is removed from it.

The video in this article will clearly acquaint you with the stages of working with gypsum plaster.

What to look for when choosing a material

When buying gypsum-based plaster (gypsum plaster mixes), experts recommend paying attention to its manufacturer. In the construction and finishing materials eat pretty big choice these kinds of mixtures. achieve positive result is possible only if the product is produced by a well-known company whose products received positive reviews users.

Gypsum plaster mixtures are produced by the following brands:

• Baumit;
• Knauf (see Knauf facade plaster: material characteristics);
• Litox;
• Polirem;
• ArtEko, etc.

According to experts, Knauf gypsum plaster mixtures are of the highest quality and most reliable in use. It can be easily used by both experienced and novice craftsmen.

Gypsum-based plaster produced by this manufacturer has the following positive properties:

• Uniform connection of dry powder with water.
• Can be used for finishing different surfaces: brick, their gas - or foam concrete, tiled, concrete, etc.
• No shrinkage process, and, as a result, the formation of cracks after drying.
• Economic consumption of working solution.
• The most even distribution on the surface.
• Minimizing the time required for finishing work.
• Environmental friendliness.

Note. It is also important that the Knauf gypsum plaster mixture has such a property as sound insulation. This is extremely important. If Finishing work held on premises panel house where sound isolation is poor.

At the end

This became possible due to the fact that in the production process such an environmentally friendly natural component as gypsum is used as a basis.

As a result of the use of special additives, gypsum plaster mixes produced by this brand do not spread on the surface. This makes it possible to use them when working on an angled surface, finishing or leveling slopes and corners.

By choosing the plaster of this manufacturer, you can be completely sure that the mixture will fulfill all the functions assigned to it, and the work surface will have an attractive appearance for a long time.