Gypsum dry mixes. Dry building mixtures based on gypsum

Smooth walls are the key to quality repairs. And one of the simple and reliable ways to level and decorate walls is to plaster them. In this article we will examine in detail all the issues related to gypsum plaster: what it is needed for, what its features and technical characteristics are, pros and cons, and areas of application. We will also clearly show how to work with this material.

Application of gypsum plaster

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

It can be placed on such bases as:

• brickwork and clay walls;
• over concrete walls and cement plaster (requires concrete contact treatment);
• on old gypsum plaster, provided it has good strength;
• for cellular foam concrete, aerated concrete and expanded clay concrete;

Since gypsum is capable of absorbing moisture, it is used only for interior decoration in dry rooms when preparing the surface for painting or wallpapering.

Current prices:

Gypsum plaster

What's 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 state. The following may also be added to the composition:

• fillers that reduce weight and increase the thermal insulation properties of light plaster: perlite, vermiculite, foam glass or expanded polystyrene;
• plasticizers and 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 its hardening time.

Gypsum plaster is an environmentally friendly material and is absolutely not hazardous to health. Moreover, due to its hygroscopicity, it is able to “breathe”, that is, absorb excess moisture and, on the contrary, release it, 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. In some cases, gypsum polymer compositions can also be used for exterior finishing work.

Specifications

The quality of mixtures based on gypsum binder is regulated GOST 31377-2008 .

• According to this document, the main indicators of dry material include:
• humidity: moisture content is allowed no more than 0.30% of the total mass;
• maximum size of granules (grains);

volumetric weight: 800-1100 kg/m3 (loose) and 1250-1450 kg/m3 (compacted).

• Properties of the prepared solutions:
• water consumption when 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 melted sample of the prepared solution (~600 g) should not exceed 165 mm (±5);
• setting time - at least 90 minutes for machine-applied mixtures and 45 minutes for manual plastering;
• complete drying time - after 5-7 days; this indicator depends on the additives in the mixture and differs among different manufacturers; You can find out exactly how long it takes for the plaster to dry in the instructions on the package;
• ability to retain moisture without allowing it to drain: at least 90%;

consumption for a layer of 10 mm is 8.5-10 kg/m2 (manual application) and 7.5-9 kg/m2 (machine application).

• Properties of gypsum plaster in hardened form:
• compressive strength - 2.5 MPa;
• surface adhesion force - 0.3 MPa;
• density - 950 kg/m3;
• vapor permeability - 0.11-0.14 mg/ppa;
• thermal conductivity - 0.25-0.3 W/m*C;

shrinkage - does not shrink

Although the vapor permeability (the ability to transmit water vapor) of plastered surfaces is not regulated by GOST, it is also an important technical characteristic that determines the scope of application of the plaster.

When purchasing gypsum mixtures, you should pay close attention to their shelf life. Due to their ability to easily absorb moisture, they cannot be stored for longer than 6 months from the date of release. After this period, their properties change, they begin to clump, and high-quality leveling of 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 purchase plaster in torn bags.

Advantages and disadvantages

• The main disadvantages of this material include
• Low moisture resistance;
• Low strength - a surface plastered with gypsum can be scratched or chipped quite easily.

The cost is slightly higher than the cement-sand mixture, about 15-20%, but this is an insignificant disadvantage.

• But still, gypsum has many more advantages.
• No shrinkage: for cement mixtures it is a couple of millimeters per square meter;
• Surfaces plastered with gypsum are smoother, without pores or graininess;
• Good adhesion: gypsum mortar adheres to the surface much better than sand-cement mortar; therefore, reinforcing mesh may not be used to strengthen the surface; it is required only in new stands due to possible shrinkage of the building;
• Good heat and sound insulation 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 place less load on the foundation;
• Cost-effective: when comparing costs, many people pay attention only to the weight of the pack; however, it is also necessary to take into account the specific gravity of the mixture - after all, the consumption of gypsum per 1 m2 is 9-10 kg, while cement for plastering the same area will require 16-18 kg.

Expert opinion

Alexander Guryanov

Plasterer and decorator

Many people attribute the advantages of gypsum to a higher setting speed than that of 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 one coated with a cement composition.

You should not hesitate when working with it - smoothing out the solution that begins to harden will be problematic. Do not dilute the mixture too much if you are working on your own. It is better if one person does the cooking and the other does the plastering.

How to dilute dry mixture

Let's consider the preparation process and 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, 1 kg requires 600-700 ml of liquid, that is, a 30 kg bag of plaster will require about 20 liters of water.

A small amount of solution 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 hammer drill with a mixing attachment or a construction mixer.

The solution should stand for 3-5 minutes (reaction time of the components). Then it is thoroughly mixed again until all lumps disappear completely. The solution should be viscous and plastic, but under no circumstances should it flow off the instrument.

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 occurs quite quickly, so gypsum plaster hardens quickly.

To make a solution convenient to work with, 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 hardening time;
• tartaric, citric acid will also slow down setting. WITH special liquids, for example, Plast Retard PE, can extend the setting time to several hours, prevent the appearance of cracks and improve the wear resistance of gypsum.

Use in damp rooms and outdoors

As we have already mentioned, gypsum plaster is capable of absorbing moisture, so its use in wet rooms and especially for facade finishing is not advisable.

If it is necessary to make the gypsum surface moisture-resistant (for example, when preparing to lay tiles in the bathroom), it is coated with a deep penetration primer based on acrylic. Concrete contact soil is ideal for tiles.

Polymer waterproofing mastic, for example, Plitonit Gidroelast, also has good moisture-protective properties. It is applied on top of a thoroughly dried layer of plaster using a brush or roller in several layers. Each of them must be applied after the previous one has dried. Gluing of tiles is allowed only one day after application. It is recommended to fill the outlets 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 discussion, 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 mixture consumption in the absence of large irregularities with a layer thickness of 1 cm is on average 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 gypsum beacons - a small amount of mixture, which is applied pointwise or along a line to the wall and leveled; after they have dried, a mortar is poured between them, and then the entire plaster mass is leveled using building rules; the thickness of the layer will be equal to the height of the beacons;
• to remove dust, protect against the shedding of small particles and strengthen the surface after plastering, the surface must be primed;
• to obtain a flat surface, the walls are additionally puttied before painting or gluing thin wallpaper;

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

Grouting and glossing

Grouting is the manual removal of small irregularities, seams, and transitions between layers. Usually they are rubbed down 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 clearing the grater of the solution. Particular attention is paid to the corners.

The video above (time 5:35) shows the process of glossing the surface - creating an ideal 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 plaster that has just set and is still wet. This saves time and eliminates the need to apply putty.

Finishing of aligned walls

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 were 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 is it better to choose which one, and can it be mixed?

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

In our renovation, we settled on the one in the bathroom. To complete the process, all we have to do is sand the seams and putty the ceiling. So we come to a slightly unusual variety of cement mixtures - these are polymer-cement putties and polymer-cement grouts.

In their composition, these mixtures are similar to tile adhesive - the same gray or white cement, the same cellulose thickener, polymer. But either fine quartz sand (fractions up to 0.3 mm) or marble or limestone flour with the same particle sizes is used as a filler.

Polymer-cement putties

Let me remind you that puttying is the final leveling of the surface, with a layer of 1 mm to 1 cm, before subsequent plastering, painting, wallpapering, etc. Polymer cement putties are used both in facade work, as a finishing layer on lime-cement plasters, and when leveling surfaces inside dry and wet rooms. When working with these putties, you must remember that the working capacity of a solution based on them is 2-3 hours. In this case, the coating turns out to be quite hard - the skin must be chosen larger.

Polymer cement grouts

A type of polymer-cement putty - grout for tile joints. Grouts are divided into white, gray and colored. White and gray are completely identical in composition to cement putties. When producing colored cement, an inorganic pigment is introduced into white or regular cement. Grouts play both a decorative and protective role in the tile covering. Thanks to the polymer introduced into the cement, usually a type of vinyl acetate (remember PVA glue), grouts do not allow moisture to pass into the tile joints, thereby protecting the adhesive layer.

Grouting compounds provide limitless possibilities for design imagination. The picture shows dark brown grout, into which bronze powder was introduced during mixing. The effect is a dark brown metallic color.

White grout can be tinted with tinting pastes, resulting in completely unusual colors. By the way, in mosaics, cement-based grouts play the most important role, also acting as an adhesive solution: the solution holds the mosaic map grid. Ground marble or limestone is used as a filler in grouting compounds, since quartz can scratch the glaze of the tile.

You can use white or gray putty as mosaic adhesive, but in this case it is necessary to add acrylic latex (or acrylic primer) to the mixing water.

Gypsum-based mixtures

These are the lightest and most convenient compositions to work with. Their only drawback is that they can only be used indoors in dry rooms.

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

Gypsum mixtures are divided into:

• Gypsum putties

They consist of a gypsum binder (we will further call it gypsum, although a mixture of alpha gypsum and anhydride is used in production), quartz or limestone filler, cellulose thickener and redispersible polymer. Gypsum putties can be applied in a layer of 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: plaster that gets into even a small wound causes very unpleasant sensations.

• Gypsum plasters

Dry mixes that have earned the highest recognition among professional builders. They are lightweight, easy to work with, do not shrink (unlike lime-sand-cement putties), quickly harden on the surface and have a fairly high working capacity - 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 the consistency of thick sour cream is obtained.

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

• Gypsum-based assembly adhesives

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

• Gypsum floor mixtures

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 putties consisting of almost 100% filler - finely dispersed 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. When diluted, they work for 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.

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

Gypsum plaster

Today there is a huge variety of mixtures in composition and binder that can be selected for specific jobs and surfaces.

To make the surface even and smooth, as well as to final prepare 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;
• possessing astringent properties.

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

Composition and characteristics of gypsum plaster

The main component of gypsum plaster is gypsum. This material has been used for treating premises for many years, since the mass is quite cheap.

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

Due to their astringent structure and composition, gypsum solutions can reduce the cost of the solution, giving it greater elasticity. In turn, polymer additives impart impermeability to the substance and also increase adhesion to the wall being treated.

This substance is manufactured according to GOST in the form of a dry powder. To dilute it for further use, you need to maintain a proportional ratio of dry powder and water. The thickness of the solution depends on what work is being done and in what room the finishing is planned. If you need to level the walls in a room, you should dilute a more liquid solution; it will be easier to distribute over the surface and easier to apply in a thin layer. To eliminate the curvature of structures, you will need a thicker consistency that will hold its shape well.

The universal composition and technical characteristics of the mixture allow you to use it yourself, both for preparatory work and for finishing the premises.

Advantages and disadvantages of the mixture

Today, leveling walls with gypsum plaster is used quite often. The gypsum mixture has found its wide application in interior finishing work and has the following advantages:

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

Like any other finishing materials, gypsum mixtures have certain disadvantages that are worth paying 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 manufactured in accordance with GOST, and its application was correct, such a coating will hide any unevenness and create an ideal, flat surface.

Do-it-yourself sequence of work

Before you begin the plastering process, you need to decide on the amount of material you will need to finish the room.

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

To apply a solution 10 mm thick, you will need ≈9 kg of dry matter per 1 m2. 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 be homogeneous, and not everyone can achieve this with their own hands. For such purposes, you can use a construction mixer. It is better to leave the resulting solution for a few minutes to gain strength, after which you can begin plastering the walls.

To achieve maximum adhesion, it is better to throw the gypsum solution onto the surface, and distribute the mass from bottom to top using a trowel or rule. If the walls in the room are too deformed, you won’t be able to do it yourself with your own hands and a trowel, it’s better to use beacons.

If the surface requires too thick a layer of plaster, 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 ready-made 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 using a sponge trowel.

Are you wondering how long it takes for gypsum plaster to dry? After 5-7 days from the moment of applying the mixture, the surface will finally dry out, and it will be possible to continue with the following finishing work.

What gypsum-based mixtures are most popular?

Decorating the walls of the house with gypsum plaster

Today in the construction market there are a huge number of companies that produce plaster mixtures. 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.

1. Volma

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

1. 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 is not particularly cheap. Thanks to this gypsum plaster, you will carry out finishing at the highest level with your own hands.

1. Prospectors

The manufacturer "Starateli" took care of producing plaster according to GOST in several variations, which have various technical characteristics: dry mix, moisture-resistant, etc.

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

More detailed comparative characteristics of these three representatives are shown in the table.

No matter how high-quality the gypsum plaster is, mixtures based on this ingredient have a short shelf life - no more than half a year. To preserve technical characteristics, the mixture must be dry and undamaged in the package.

Tile and gypsum plaster in the bathroom: can they be combined?

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 taking into account certain subtleties of this process, because cement plaster, usual for such work, has a long list of distinctive features from gypsum.

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

For wet rooms and bathrooms, the material must comply with GOST and be stable in high humidity. It is better that the plaster contains astringent additives, which will provide excellent performance characteristics.

Every day, the use of tiles in the bathroom is receding further into the background, because dry plaster based on gypsum for treating wet rooms is a more budget-friendly and original option.

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

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

Plastering walls

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

Gypsum plaster

The most popular now are dry mixtures for plaster based on gypsum. Their main advantage is a very simple application process. This 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 Layer, Forman 10, Osnovit Gipswell, and Prospectors. They differ little in quality from each other, but some types cannot be used in wet areas.

We should also talk about universal mixtures for plastering walls from Knauf-Rotband. The price for a 30 kg bag is 360-390 rubles, which is more expensive than all similar options. There are also packages for sale in 5, 10, and 25 kg.


This mixture has been produced in Germany for half a century, and it appeared in Russia 20 years ago. It has become so popular that some are accustomed to using the name “Rotband” to refer to any dry plaster building mixtures made from gypsum.

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 differences are greater, then leveling is done using).
• The minimum layer thickness is 0.5 cm (1 cm when laying tiles).
• The average drying time is 7 days, depending on humidity and thickness.
• Suitable for plastering walls and ceilings made of concrete, brick, and polystyrene foam surfaces.
• This mixture is not suitable for sealing joints between sheets of drywall. To do this, use gypsum-based putty - “Knauf Uniflot”. Read more about it in our article.
• Recommended for use in rooms with normal air humidity; can be used in the kitchen or bathroom.
• Color ranges from white to gray or even pink. It depends on the amount of natural impurities, and does not affect the characteristics of the material in any way.
• Shelf life – 6 months.

A thicker layer can be applied to the walls after the first layer of maximum thickness has completely dried. Applying more than one layer of plaster on the ceiling is unacceptable.

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

• Obtaining a smooth surface.
• No cracks even on a thick layer of plaster (provided the technology is followed).
• The consumption of the mixture is half that of cement-sand types.
• Possibility of applying a layer of up to 5 cm in one approach without spraying the surface.
• The solution does not lose all moisture even on porous substrates or at elevated temperatures, which ensures uniform drying without delamination and without cracks.
• The composition does not contain harmful substances and is completely safe.
• By adding polymer additives to the composition, the mixture provides enhanced adhesion, which allows it to be used even on the ceiling.
• The mixture contains special additives to increase 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 stirring, use the mixer attachment 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 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, during cooking, all elements are added “by eye.” You can use the following instructions.

• The preparation of a solution for plastering walls begins with sifting sand. To do this, you will need a sieve with cells of about 4 mm; for dry sand, you can use a finer mesh. When the sand is ready, begin making the solution. To do this, pour 2.5-3 liters of water into a 10-liter bucket.

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

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

Dry cement based mixture

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

For example, the following types are available for sale:

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

Cement-lime mixtures

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

This option is also good for use in private homes due to its bactericidal properties - this is additional protection against fungus. Lime mortar is chosen mainly for rough finishing of walls in rooms with normal and low humidity. Unlike cement mortar, a lime-based mixture is well suited for plastering over shingles because it adheres well to the wood surface.

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

Composition of lime mortar for plaster:

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

The mixture turns out to be very elastic and adheres well to the wall; after drying, no cracks appear on the surface. Liquid soap adds a pleasant scent and increases elasticity.


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

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

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

This composition will stick well and stay on the wall, level with the rule and rub well. Costs for plastering 250 sq. m. such a mixture will cost approximately 22,200 rubles. (for material):

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

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

Dry mixture based on lime-cement

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

• "Knauf Sevener" (universal mixture);
• "BEST";
• "Osnovit STARTWELL" and "FLYWELL";

Plaster mixtures for facades

In private houses, in addition to interior decoration, exterior wall decoration is required. Many owners, out of ignorance or in order to save money, plaster their facades with the same mixture that was used for interior decoration. This is strictly not recommended, since external walls require a mixture that can withstand exposure to the environment without collapsing. Below we provide a list of good plaster mixtures for finishing facades.

Mineral plaster mixtures

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

Mineral plaster
Specifications:

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

Acrylic-based plaster mixtures

Synthetic plaster mixtures are made on the basis of acrylic dispersion. They are sold ready-made in a liquid state and do not require additional preparation.

Acrylic plaster
Specifications:

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

Silicate plaster mixtures

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 mixtures

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

Silicone plaster
Specifications:

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

We looked at 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 prepare it yourself according to the proportions given above.

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

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

In addition, the composition of gypsum plaster includes lightweight 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. Fillers also significantly reduce plaster consumption and make the surface more durable. Polymer components increase the elasticity of the material, as well as its adhesion to various substrates.

Universal gypsum plaster is supplied in the form of a powder mixture in paper bags of various weights. It requires water to prepare it. By adjusting the amount of liquid, you can change the fat content of the plaster, depending on your goals. For finishing leveling on a pre-prepared surface or decorating the finished coating, prepare a liquid solution that will spread well on the wall. To fill cracks, potholes or rough leveling, prepare a denser mixture.

Gypsum plaster is supplied dry

General information

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

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

Advantages and disadvantages of plaster

This material has become widespread due to its positive properties:

• The gypsum plaster mixture is 95-97% made from materials of natural origin that do not emit toxic substances when heated or wet.
• After drying, the result is a perfectly even coating of a pleasant shade, so further finishing with wallpaper, tiles or paint is not necessary.
• High adhesion to almost all surfaces, thanks to which the material does not lag behind the wall.
• The relatively small weight makes working with the material convenient, and also allows you to finish ceilings.
• The plasticity of the solution allows it to be easily stretched over the surface, which significantly speeds up and facilitates the work.
• Gypsum-based plaster does not shrink, so it does not crack.
• Vapor permeability ensures 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.

There are also some disadvantages:

• Low moisture resistance, which is why the scope of use of the material is limited to dry rooms.
• You cannot 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 influenced 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 (the slope is no more than 5 mm), the consumption of gypsum plaster is approximately 300 grams with a layer thickness of 1 mm.

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 slope of 3 cm. First of all, you need to plumb the surface at three points. In the first there is a blockage of 0, in the second - 1.5 cm, in the last - 3 cm. We sum up 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 this, we multiply the 15 mm layer by 300 grams of solution required for a 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 approximately 3 mm thick; it will require another 0.9 kg. The result is 5.4 kg, add 10% for reserve and round up to a higher number. As a result, this wall will require 6 kg of facade gypsum plaster or universal mixture.

Self-preparation of the solution

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

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

The cooking rules are as follows:

• Measure portions of components using special containers.
• Mix dry ingredients.
• Add a little water and mix with a construction mixer or drill with an attachment.
• Leave to sit for 3 minutes, then stir again.

On a note! These instructions are suitable for store-bought mixtures and those prepared manually from dry ingredients. For lime-gypsum mortar, gypsum is first soaked in water, mixed, and then added to the lime dough.

Preparing walls for plastering

Before rough finishing of walls with gypsum compounds, the following steps must be taken:

1. Remove the old coating and clean the surface from grease stains, dust, wallpaper and paint residues.
2. Tap the surface with a hammer to identify weak fragments of the wall and remove them.
3. Seal cracks, potholes and chips with polyurethane foam or cement mortar.
4. Prime the walls twice with an interval of 4 hours.

Important! When the thickness of the applied gypsum mixture is large, it tends to fall off quickly, so 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.
• Using metal scissors, cut the mesh into fragments of the required area and shape.
• Place the product against the wall and secure it with self-tapping screws.

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

Procedure for applying gypsum plaster

The prepared solution should be applied in one layer no more than 5 cm thick without a mesh, no more than 8 cm with a mesh. The solution is scooped up onto 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, apply the tool to the bottom of the wall and move it upward, making zigzag movements.

You should know! It is impossible to use gypsum plaster that remains on the blade of the rule, since 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 irregularities are puttyed and smoothed with a wide spatula. Marks from the rule can also be smoothed out with a spatula. The next procedure should begin in about half an hour. But if the surface is pressed with your 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.
• Take a sponge grater, press it against the wall and make circular movements.
• Use a wide spatula to smooth out the entire coating.
• Wait 5-7 hours and repeat the procedure.

Surfaces plastered in this way do not require subsequent puttying.

At this point, the application of plaster can be considered complete. 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 or operating heating devices in the room. In addition, coatings should be protected from direct sunlight.

After 3 days, it is necessary to ventilate the room to remove excess moisture. Temperature range – +5…+25 degrees.

On the modern construction market you can find equipment such as plastering machines. It should be immediately noted 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, and a nozzle for controlling the intensity of the material supply. Also included is a power cable, compressor and setup panel.

Procedure for applying plaster:

1. Load the finished mixture into a container.
2. Connect the equipment to the network and pick up the supply hose.
3. Point it at the wall, while holding it 30 cm from the surface to be treated.
4. Turn on the plaster supply and move from bottom to top.
5. The layers of material should overlap each other.
6. At the end, the material is leveled and rubbed in the same way as in the case of the usual application option.

How long does it take for gypsum plaster to dry?

In a well-ventilated room, subject to proper temperature conditions, complete drying and strength gain of the material occurs in 7-14 days. After complete drying, the coating acquires an even light color. At this stage, you can begin further finishing. If you have chosen tiles, you can simply apply glue and install it. If you plan to paint, the wall humidity can be no more than 1%.

Important! Accelerating drying of coatings using heating devices is prohibited.

Basic requirements for the quality of gypsum plaster

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

The surface must contain barely noticeable pores; if there are none, then the vapor permeability will be lower than required by the technology. If the pores are too large, it means the solution was poorly mixed. This can be corrected with a layer of decorative plaster.

On a note! You cannot evaluate the quality of the coating in poor lighting.

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