The correct proportions of mortar for plaster walls. Plaster mortar: composition and preparation How to prepare a mortar for plaster

20.11.2019

No renovation or renovation project is complete without the use of plaster. Although its application is carried out at the very beginning of the repair, it affects the final result of all finishing work.

Incorrect mortar proportions, insufficient understanding of what affects its adhesion can significantly affect the quality of the repair performed.

Therefore, the construction team is required to know what kind of composition may be required for various walls: gypsum, brick, clay, etc.

The composition of the plaster includes several important components that contribute to adhesion, as well as giving the solution special properties. For its preparation, the following astringent elements are traditionally used:

Cement.

Affects the degree of strength of the plastered wall after applying the plaster, the grade of the material can affect the adhesion and degree of adhesion of the composition to the surface;

Clay.

It is used for the preparation of solutions necessary for plastering surfaces with a high heating coefficient. Most often, this composition is used for finishing furnaces, as well as wooden houses.

It can also be used as a plasticizer if it is necessary to reduce the amount of cement in the solution;

Lime.

Increases the plasticity of the solution and makes it easier to work with it. Walls plastered with this substance have antifungal properties.

Another reason that slaked lime is added to the composition of mortars is that moisture from such a surface evaporates much more slowly, as a result, it becomes much easier to work with PCS;

Gypsum.

This additive is used if it is necessary to speed up the drying of the applied mortar. The disadvantage of this solution is the need to quickly develop such a composition, after 10-15 minutes it hardens, and it is impossible to work with it.

In addition to binders, sand must be included in the composition of the solution. As a rule, fine-grained material is used.

Plasticizers can be added to the resulting solution to impart additional properties to PCS: resistance to high temperatures, water resistance, and an increase in thermal insulation properties.

Possible options for plaster and methods of its application: cement or lime?

All plaster solutions can be divided into several types according to their composition, as well as the method of their application.

The following types of compositions are most often used:

Cement.

Suitable for almost any type of surface: brickwork, floor slabs, etc. Can be applied to interior and exterior walls of a building. In most cases, in its pure form, it is used only during capital repair work.

Clay.

Universal composition for plastering wooden houses, as well as surfaces exposed to high temperatures.

The disadvantage of such a mixture is low strength, therefore, to eliminate this disadvantage, it is necessary that the top layer be covered with lime or lime-gypsum composition.

The advantage of clay is its high thermal insulation properties.

Lime.

Gypsum.

Dries quickly, has high adhesion to any surface. It is a universal solution that can be used for any walls. Most often used for plaster walls and partitions.

Cement-lime.

Mainly used in capital construction new buildings. The use of such solutions increases the speed and quality of work several times, and also increases the strength of the walls, due to the slow evaporation of moisture from the surface, the likelihood of cracking is reduced.

Application is limited to dry rooms.

Lime-gypsum.

Most wide application received in the plastering of wooden surfaces. To increase the drying time, various plasticizers are added to it.

It is used for finishing inside the building, exclusively in dry rooms.

Lime-clay.

Used to fix clay plaster. In most cases, it is not used as a separate solution.

In addition to their composition, plaster mortars can be divided according to the method of their application:

Simple.

In this case, only two layers are applied: primer and spray. The plane is not checked using the rule, all irregularities are eliminated with a trowel. The layer thickness is about 12 mm.

Improved.

Work is carried out with the help of the rule. Three layers of mortar are applied: soil, spray and coating. The latter is rubbed with a grater. Thickness is about 1.5 cm.

High quality.

Deviations from the vertical level are minimal. Defects in the plane of not more than a few millimeters are allowed.

Strict requirements are imposed not only on the composition of plaster solutions, but also on their application, since the final result of the work performed depends on this.

The master is also required to have a good understanding of the manufacturing process and proportions for each type of mortar.

Proportions of different types of solutions for plastering walls with your own hands

In order to plaster the surface with simple method it is necessary to observe the following proportions for each type of solution:

Cement.

Cement and sand are used as fillers. For the soil, the ratio is 1:3, for spraying - 1:4, for the covering layer - 1:1.

Clay.

Clay-sand composition. For all layers, the same ratio of 1:3 or 1:4 or 1:5 is used.

Lime.

The composition includes slaked lime, sand. Proportions for soil - 1:2, for spraying - 1:3, for covering 1:2.

Gypsum.

The same ratio for all layers.

Cement-lime.

The composition includes the following components: cement, lime, and sand. For each layer, the ratio will be: soil 1:1:4; spraying and coating is done in a ratio of 1: 1: 3; 1:1:2.

Lime-gypsum.

Used lime, gypsum sand. Ratio for primer:1:1.5:2; for spraying 1:1:2. Covering is done without the use of sand in a ratio of 1:1 or 1:1.5;

Lime-clay.

Composition lime, clay, sand. The proportions of such a solution are identical for each layer 0.2:1:3-5.

In addition, in order to understand well the necessary proportions for each type of mortar used, the construction team must have everything necessary equipment and tools for its preparation.

What is needed to make a solution?

Quantity necessary tools depends on the total amount of work performed. Usually for overhaul in an apartment you may need:

Concrete mixer. If ready-made building mixes are used, a mixer can be used.
Capacity. For these purposes, a galvanized trough and other containers can be used.
Owl shovel. It is used for mixing the solution and pouring it into buckets for supply to the working team.
Clean buckets for water.

Some construction teams may use additional equipment.

What should be considered when preparing solutions?

Proper preparation of plaster compositions will significantly reduce material overruns and produce the required amount of mortar for the planned scope of work.

Cement.

The components of sand and cement are mixed in the required ratio, until a homogeneous mixture, after which water is poured. The loss of cement milk is strictly not allowed. The solution is kneaded until a homogeneous mass. Approximate one to one ratio; water for each bucket of cement used.

If the solution is mixed with a concrete mixer, water is first poured into it in the required ratio.

Clay.

Often requires soaking the material. In this case, a clay-sand mixture is laid out in a container and filled with water so that it covers the surface by several millimeters. Another layer is laid on top and the operation is repeated. The next day, everything is thoroughly mixed.

Lime.

The density of slaked lime is preliminarily determined and, if necessary, can be diluted with water to the required consistency, after which it is added to the sand-cement mortar.

Gypsum.

Water is taken in a ratio of approximately 0.7 liters per 1 kg of the mixture. Dry gypsum is added in a thin stream to a container filled with water and mixed with a mixer.

Cement-lime.

It is made in a similar way as the lime mixture. Then it is added to the finished cement mortar.

Lime-gypsum.

Gypsum is added to the already prepared lime mortar. Since hardening occurs within a few minutes, the batch must be done in those proportions that can be quickly worked out.

Lime-clay.

To begin with, a greasy clay solution is made. Then lime is added to it in the required proportions.

Self-production of solutions requires practice and a good understanding of the reactions that the binder elements that make up its composition enter into. To facilitate the work of builders, you can use ready-made building mixtures.

Methods for preparing dry ready mixes

In order to obtain a plaster mortar, you will need to mix the dry mixture with a mixer and add water. For a simple plaster using the Knauf "Start" mixture, you will need:

reading capacity, with a capacity of about 25 liters;
water. 18 liters;
mixture bag 30 kg.

In the prepared cold water Pour the contents of the bag thoroughly mixing it with a mixer. It is necessary to obtain a uniform homogeneous composition. After completing the work, it is necessary to work out the mixture within half an hour.

For finishing plaster, the Knauf "Multi-Finish" mixture is suitable. The ratio of water per kilogram of dry mixture is 0.45 liters. It is necessary to knead the solution in a manner similar to the Knauf "Start" mixture.

The construction team needs to take into account many points when deciding which mortar the room will be plastered with. But knowing the basic proportions of preparing a building mixture, you can quickly plaster any walls.

Plastering walls is no easy task. It directly affects the quality finishing walls. If you decide to do this work with your own hands, then we will tell you how to prepare a mortar for plaster, the proportions in which must be strictly observed. Otherwise, you can get not a smooth, even and durable surface, but a loose, porous layer of mortar, ready to fall off at any moment.

In the article we will answer questions about the composition and proportions of the mixture based on various components, we will talk about the requirements for mortars for plaster, as well as about the types of various modifying additives.

Buy ready mix or make your own

In this matter, the main role is played by the finishing area, as well as the physical and financial capabilities of the owners.

Ready plaster mix.

The composition, in addition to the main selected and high-quality components (cement, sand), includes many special additives - modifiers, plasticizers that improve the working and operational qualities of the plaster.

But the price of such a mixture is much higher than that of a do-it-yourself solution. Therefore, it is unprofitable to use ready-made plaster on a large area. But if you need to finish a small surface, then it is better to purchase a ready-made composition. You don’t have to buy all the components separately, charge the mortar mixer, and it will take less time.

Do-it-yourself plaster mixture.

When you have to finish a large brick or foam block house, then to reduce the cost of work, the owners usually prefer to prepare the plaster mixture on their own. Cement, sand are bought, a small mortar mixer is installed, and little by little, in portions, a solution is prepared.

In this case, you have to work with your hands and spend some amount of personal time. But as they say, "your work does not count."

When working independently, it is necessary to strictly observe the proportions of the mortar for wall plastering, otherwise there is a risk of reworking all the work already at the application stage. Even worse, if a low-quality solution begins to fall off at the stage of finishing, fine finishing.

It is possible to correct such a marriage only with the complete removal of the applied plaster and replacing it with a new layer. And this, as you know, additional and considerable costs.

Types of cement mortar, requirements, proportions

There are few types of mixtures, but each requires separate consideration, as it has its own unique characteristics. They differ in the presence of various additional components in the solution.

So, the plaster mixture can be:

Used for leveling and finishing. Such a mixture is compatible with any rough surfaces, except for concrete, due to weak adhesion to the latter.

This mixture is mainly used for rough plaster; for finishing, sand of a very fine fraction is needed. The mixture remains "alive" for an hour, after which the technical parameters deteriorate.

Lime-cement.

Used for finishing brick or concrete surfaces. Lime gives the solution plasticity, which facilitates its application and stretching. It also increases the vapor permeability and strength of the solution, extends the "survivability" of the mixture up to 3 hours.

In addition, lime has bactericidal properties, on walls covered with lime mortar, mold will never form, fungus and microorganisms will not appear. But the proportions of lime mortar for plaster must be observed in order to avoid lime stains on the walls.

Lime "efflorescence" will bring a lot of trouble when finishing, since not all paints or putties are compatible with this material.

Gypsum-cement.

It is applied to the improved plaster of walls. Gives an even, durable layer that can be easily sanded. Seizes quickly, so it is not recommended to cook immediately a large number of solution.

If it is necessary to prepare a lot of mortar, then setting retarders are used to extend the "life" of the plaster mixture. They are already present in ready-made mixtures.

Important! In mixtures prepared independently, depending on the air temperature, the type and quality of the surface, the type of room, it is necessary to add special components. Properly selected mineral fillers, polymeric additives or plasticizers will make the solution more plastic, frost- or heat-resistant, enhance adhesive and astringent properties.

Cement-sand and lime mortars are used for interior or exterior walls (see How exterior walls are plastered) exposed to moisture, gypsum-cement mixtures are used only for interior work in dry rooms.

Requirements for the components of the solution

The composition of any plaster solution includes three main components: cement, sand and water. The strength and durability of the applied layer, as well as the quality of grinding and subsequent finishing, directly depend on their quality.

So:

Cement.

This is a binder component that plays a major role in the formation and hardening of the solution, giving the mixture strength and water resistance.
The proportions for the preparation of the plaster mortar are standard. it is recommended to use Portland cement or Portland slag cement at least M300.
It depends on the brand what proportions of cement and sand for plastering will need to be taken: the higher the brand, the more parts of sand need to be added per unit of cement.
This material also has a shelf life, the fresher the cement, the better the performance. It is advisable to purchase it in paper bags and store it in a dry place.

Cement is not afraid of frost, but from high humidity, the hardening process can begin right in the package.

Sand.

This material is the filler of the plaster mixture, it determines the strength, weight, thermal conductivity and density of the solution.

When interacting with cement, sand creates a monolithic layer with the properties of solid rock.
For rough plaster, fine-grained ravine sand is taken, in which a small presence of clay is allowed.
If there is a lot of impurities, then the solution is able to settle and delaminate. It will have to be constantly mixed, and it is still difficult to work with it, as the ability of the mixture to stick and level is reduced.

For an improved layer, river sand is best - or ordinary, but clean, sifted through a fine sieve, washed from impurities. And again, we must not forget about the proportions - cement-lime plaster will turn out to be of higher quality if the sand in it does not contain clay impurities, and the amount of filler does not exceed the required volume.

Water.

The liquid for the solution must be clean, free of oil impurities, various organic and chemical contaminants, debris.
All impurities after evaporation of the liquid will remain in solution and can significantly affect the quality of further finishing.
Oil stains will show through the plaster or wallpaper, the paint will peel off in this place. The same can happen from the presence chemical impurities. Therefore, experts recommend using clean, better drinking water.
When mixing with water, the cement setting process begins in the plaster mixture, therefore, after kneading, the solution must be worked out within 1 hour.

Longer storage of the mixture reduces specifications material, and complicates the work.

Proportions of components for different types of solution

Any instruction requires strictly observing the proportions of cement and sand for wall plastering, so that the work is quick and pleasant, and the result is pleasing with strength and reliability.

If there are no plasticizing additives, then to improve the plastic properties of the solution, the masters advise adding a little neutral liquid soap or soap solution:

In the cement-sand mixture, the composition of the main components should be as follows:

Grade of cement	Cement/sand, parts	Produced brand of mortar
M300	1/3,5	M100
M300	1/2,5	M150
M400	1/4,5	M100
M400	1/3	M150
M500	1/5,5	M100
M500	1/4	M150

Water is added to the mixture gradually, with constant stirring. The solution is brought to the consistency of thick sour cream.

Important! Too plastic mortar will lie unevenly on the wall, drain, and when leveled, it will reach for the tool. A hard mixture will stick to the trowel, making it difficult to throw it on, and when it dries, it will shrink and crack. You can recognize a normal solution by immersing a trowel, the mixture should leave a thin layer on it without adhering lumps.

Lime mortar for plaster, proportions:

Grade of cement	Cement/lime/sand, parts	Produced brand of mortar
	1/0,3/4	M75
	1/0,2/3,5	M100
	1/0,1/2,5	M150
	1/0,5/5,5	M75
	1/0,4/4,5	M100
	1/0,2/3	M150
	1/0,8/7	M75
	1/0,5/5,5	M100
	1/0,3/4	M150

When cement-lime plaster is used in the decoration, the proportions of lime in the composition of the solution are small, so it is better to purchase ready-made lime paste at a hardware store. It is rather problematic to prepare the necessary component with your own hands, the term for slaking and aging lime is about a month using a special technology.

An improperly prepared or unripened mass can destroy the plaster mortar and nullify all work.

Modifying additives

Separately, it is necessary to talk about additives in the plaster mortar, with them the mixture will acquire some important properties necessary both for applying and treating surfaces, and for their further operation.

Here, too, it is important to maintain proportions for wall plaster: each package has detailed instructions on the use of the additive, and it must be strictly followed:

Setting accelerators or retarders.

These are components that act on the crystal lattice of the binder and regulate the time of its formation (setting).

It is desirable to make them, for example, in a gypsum-cement mixture to extend its "survivability". In this case, casein or bone glue serves as such an additive.

Additives to increase plasticity.

These substances, getting into the solution with water, form a lot of bubbles, due to which the liquid evaporates less and is absorbed into the surface, which means it stays in the mixture much longer. They are recommended for simple, traditional cement-sand mortars that quickly lose water and delaminate.

Antifreeze additives.

Basically, it includes various special salts that slow down and even exclude for some time the freezing of water in solution, which means they reduce the risk of loss positive qualities mixture as the temperature drops.

I must say that they operate mainly up to -5 degrees. At a lower temperature plastering work it is impossible to carry out, here no additives will save the mixture from freezing.

Strength additives.

They can be of two types: some work in tandem with a binder, by means of chemical action they increase its properties; others act independently, personally perform a reinforcing function.

The second type is called fiber, which may consist of waste glass, pulp or metal production. Fiber is sold in the form of small chips or polymer threads, which, getting into the solution, intertwine and give the plaster additional strength.

Conclusion

If the surface of the walls turned out to be not too smooth, do not be upset - all the small irregularities will be hidden by the finishing putty. The main thing is that the plaster itself is strong, does not crumble, does not crack and does not fall off.

By correctly determining the composition and calculating the proportions of the plaster, you will get a high-quality and durable coating that will not require repairs for many years. And after looking at the photos and videos in this article, you will get answers to other questions that concern you.

But if you are still not confident in your abilities, and do not risk plastering the walls yourself, then we recommend inviting specialists who will do this work quickly, beautifully and efficiently.

Plastering is an integral part of any repair work. Through this process, improved consumer properties processed surfaces, increases the reliability and durability of the walls. Qualitatively prepared and correctly applied plaster prevents the spread of mold and fungi, removes all irregularities, chips and mechanical defects, and also helps to strengthen the base.

Features of plastering - 3 layers

It is easy to make a solution for plastering walls with your own hands. It is necessary to level the surface. This operation is required as when carrying out exterior finish, as well as internal. From the place of application of the essence depends on the characteristics and requirements. So, to carry out repair work indoors, a technological and plastic mass will be needed, while outdoor mixtures must first of all be resistant to pressure and temperature changes, frost-resistant and resist moisture.

Solutions are applied on surfaces of all types and types. Plastering of plywood, chipboard sheets, wooden elements, cinder blocks and foam concrete, brickwork, concrete is carried out. When making a suitable composition at home, it is very important to pay attention to the adhesion of the finished product when choosing components and proportions.

The correct technology for applying plaster to the ceiling and walls includes three main steps:

Spray is the first layer that needs to be applied to the building substrate. It is necessary to fill and level the largest pores and surface defects, as well as to ensure an appropriate level of adhesion and adhesion of subsequent plaster layers. During its formation additional elements, like lime and clay, are not used, and the thickness of the coating should not exceed 4 mm.
The second level, which was called the soil, significantly exceeds the previous one in volume and reaches 20 mm. Unlike liquid spray, this layer is more consistent with a thick plastic dough with its consistency. Its task is to maximize the leveling of the base plane, regardless of its roughness.
The last stage of work is the application of a coating to the surface, which is required for the final smoothing of irregularities and defects in the base. The formation thickness is from 3 to 5 mm, and so much water is added to achieve the maximum level of plasticity and viscosity of the solution. After covering, it remains only to whiten or paint the walls, or to glue decorative wallpaper on them.

What ingredients are needed to prepare the mixture?

Many beginners, when trying to make a plaster solution with their own hands, disrupt the mixing process from the very beginning. This is very important, since the key characteristics of the finished composition depend on high-quality and proper mixing. The main components include water, aggregate and binder. If necessary, enter Additional materials, including various additives and plasticizers.

Clay and lime can play the role of a binder. But the most popular and in demand is cement. It is great for preparing a mixture, which is later used for outdoor or interior decoration. At the same time, it is the most expensive option, since the rest of the ingredients are seriously inferior to it in terms of quality, reliability and strength.

Choosing among the many varieties, the easiest way is to stop at M400 brand cement. This dry mix is universal, as it meets all the requirements of GOST, as well as apartment owners. Great for bathrooms, kitchens, hallways and naturally living rooms. If the budget is limited, and repairs are carried out in low-responsibility structures, such as basements or plinths, then the purchase of Portland cement M300 would be a rational solution.

The strength of the plaster is influenced by many factors, but the most important is the brand of cement. The higher this indicator, the better the solution will turn out.

Having decided on the binder, it remains only to deal with the filler. Here, the only and indisputable favorite is ordinary sand. It is recommended to take a pure river fine fraction, which will ensure maximum mixing of all the ingredients of the future plaster. Together with cement, it forms an ideal material that is resistant to cracking and has a high level of strength.

The simplest and most popular proportion of the preparation of a cement-based plaster mixture includes one share of a binder and three parts of sand. This recipe is suitable for almost any room. Water is added until the essence of the required viscosity level is formed. For rooms with a normal level of filler moisture, you can add a little more. If plasticity is required, then the correct ratio involves the use of one portion of cement and two parts of sand.

There are many plasticizers and additives designed to increase the softness and pliability of the finished plaster, change the setting time and various characteristics solution. Home craftsmen often add detergents, soaps, adhesives, like PVA. Thanks to such materials, the adhesion of the essence with concrete base, as well as increasing the level of protection against fungal bacteria and mold.

A big misconception is associated with the technology of mixing the mixture. For some "specialists" the order in which components are added does not matter. Many first pour water into a container, then pour in cement, sand, lime and other materials. The problem is dry matter after entering the liquid, it will be converted into small lumps. It will take a lot of effort to stir them until the consistency of the required level is obtained.

In order for the solution to turn out to be of high quality and homogeneous, experienced craftsmen advise doing the following:

1. Initially, it is required to sift the sand using a sieve with small cells. Otherwise, all debris and large particles, such as shells, pieces of silt, pebbles, organic residues, will be in solution. During plastering, they will leave grooves on the surface of the wall, clinging to the spatula.
2. After that, it is necessary to pour dry cement into the sand and mix everything thoroughly. If the filler is wet, then it will need to be dried - mixing will be an order of magnitude easier when both components are dehydrated.
3. Only after that water is added, and gradually, while the solution itself is constantly mixed. It is recommended to pour in new portions of the liquid at a time when it is almost impossible to interfere.

Types of plaster solutions - different options

For the preparation of mixtures for the treatment of external and internal walls, many different components are used. So, a solution boasts great popularity, an astringent in which cement and lime act. This essence is excellent low temperatures, exposure to direct sunlight, counteracts the appearance of mold and fungi.

Unlike conventional cement plaster, lime analogues are characterized by a high level of plasticity and viscosity. This has a positive effect on their adhesion index, due to which they instantly and firmly seize with the bases of walls and ceilings of any type and kind.

In rooms with normal humidity, it is worth using lime plasters, which dry quickly and absorb excess moisture. In the best way, this composition has proven itself for brick surfaces. The absence of cement affects the strength and reliability of the mixture, in addition, it hardens within three days. But this factor allows you to prepare sufficiently large volumes of essence, because if you wish, you can always add water if the substance in the container begins to solidify.

It is recommended to use additives such as gypsum for coating and finishing wood, stone and fiberboard substrates. In combination with cement and lime, the plaster is very durable and ductile, but it is not suitable for wet walls. The presence of this substance causes a high solidification rate, which makes it impossible to prepare the mixture in large volumes or “revive” with the usual clean liquid.

Decorative cement mortars and glazing plasters, which require additional investments of money and effort, are very popular. With the help of such mixtures, you can finish the finishing of halls, corridors and hallways. In addition to the main binders, many other materials are added, including minerals, mica, slaked lime, marble chips.

If it is necessary to give a certain shade, which is typical for Venetian plaster, it is recommended to pour in color pigments. You can buy all these additives in the same hardware store where bags of cement and lime are sold.

If you plan to apply a decorative mixture in baths or near the stove, then you will need to increase the level of resistance and resistance to extremely high temperatures. To do this, it is recommended to pour fireclay powders and special refractory clays. As a result of this process, cement with the addition of these materials produces a strong essence that is resistant to heat, so that even the walls of fireplaces can be treated with it.

What is useful for kneading - let's move on to the tools

Mixing of all components of the solution is carried out in two ways - machine and manual. The easiest way is to prepare the mixture in an ordinary enameled bucket or other similar container. Having added cement and sand and thoroughly mixed everything, it remains only to pour in water in small portions and continue to knead the composition with the help of improvised tools.

If you want to make a large volume of solution, it is recommended to use a special trough or bath. Here, blunt scoops or bayonet shovels, as well as choppers with a flat base. To simplify the process somewhat, experts advise performing movements on yourself, otherwise the arms and lower back will get tired too quickly.

If there is a construction mixer, then it greatly simplifies the work. Any suitable element acts as a nozzle, be it a curved wire or a blade. Concrete mixers also make it easier to mix the mortar, but their operation is only advisable if the volumes of plaster are very large.

How to make a cement mortar for plastering walls, the proportions of the components and the conditions of use are questions that often arise during the construction of a building or the repair of a room.

Plaster can be applied to different materials from which the building elements are made. Such a layer can be located on the outer or inner side.

The question of cement mortar for wall plastering, the proportions of its components and the conditions for its use is not something very complicated and secret. Of course, any master has his own little secrets that allow only him to prepare a slave composition, but general principles preparation of a high-quality and reliable solution have been used for many years and have proven their effectiveness in practice.

Features of plaster

Plastering is the most common way of leveling various surfaces of a building during interior and exterior finishing operations. First of all, plastering is carried out on the walls and ceiling inside the room, as well as on the outer surfaces of the walls, incl. facade. This purpose of the material puts forward different requirements: moisture resistance, frost resistance, resistance to temperature differences are important for external plaster; and for interior decoration, plasticity and manufacturability come to the fore.

A layer of plaster can be applied to various materials: concrete, brickwork, cinder blocks and foam concrete, wood, chipboard, plywood. Therefore, when choosing the composition of the solution, it is important to pay attention to its adhesion to these materials.

The traditional technology of plastering walls and ceilings includes the application of three layers for various purposes. The lowest layer (spray) is applied directly to the surface of the respective building element in order to ensure the necessary adhesion of the main plaster mass and to fill the largest irregularities. Such a layer has a thickness of up to 4 mm. The consistency of the solution should be quite liquid, and lime is usually not included in the composition.

The second (middle) layer is considered a primer and has an increased thickness - up to 15-20 mm. Its main task is to level the entire plane of the wall (ceiling), regardless of the quality of the surface itself (roughness). The consistency of the solution for this layer should resemble a thick dough, and its adhesion is no longer with the wall material, but with the inner cement layer of the plaster.

The top finishing layer (covering) is intended for finishing smoothing of a surface for the subsequent painting or whitewashing. The layer thickness is usually small - 3-5 mm, and the composition of the solution should be as plastic as possible.

The principle of mixing the composition of the solution

The question of how to prepare a mortar has a simple answer: by mixing the main components such as binder, aggregate and water. And to improve the properties, additional plasticizers and other additives are introduced. The binder may be cement, lime and clay, or a combination thereof. The choice of the right binder takes into account the location of the wall (internal or external) and the purpose of the plaster.

The traditional and best aggregate is sand. Together with the binder component, it creates a single structure that has sufficient strength and resistance to cracking. The ratio of these components plays a decisive role in the formation of a high-quality and reliable plaster structure. By adding different amounts of water, the desired consistency of the solution is provided: liquid (spray), pasty (soil) or creamy. The water content of the solution affects the setting time. With the introduction of various additives, it is possible to change the plasticity of the solution, some of its properties and solidification time. If you are preparing wall plaster with your own hands, then PVA glue, soap, detergents, etc. are often used as additives.

Types of plaster solutions

Depending on the purpose and conditions of further operation, plaster has several common types:

Cement-sand mortar can be used for plastering exterior (facade) and internal walls, as well as the ceiling exposed to moisture, low and high temperatures, sunlight. Such plaster can be used for the basement of the wall from the outside. In addition, it can be used inside: in bathrooms, kitchens, bathrooms, etc.
The cement-lime binder component is used similarly to the previous composition, but has a higher ductility.
Lime-sand, lime-gypsum-sand and lime-clay-sand mortar is used as plaster indoors with low humidity.
A mixture of clay mortar with cement or gypsum, clay-sand mortar can be used as plaster for the internal walls of utility and outbuildings.

By correctly selecting the proportions of the binder and aggregate, it is possible to provide different fat content of the solution. Thus, the greasy solution has an increased content of cement or other binder in comparison with sand. The solution has a high density, mechanical strength, but without the addition of plasticizers, there is a risk of rapid cracking. In addition, such a solution has an increased cost due to the overspending of cement. Lean mortars are considered economical formulations: they have a higher aggregate content and savings by reducing the amount of cement. This composition will not crack, but has low mechanical strength. It is intended for non-responsible work. The optimal proportions of cement and sand provide a normal fat content of the solution.

Mortar Ingredients

Cement is the most durable and reliable binder, but also the most expensive.

The strength of the material depends on the brand of cement: the higher the brand, the higher the strength.

If the walls are plastered with cement mortar, then Portland cement of the M400 brand is usually used, which fully meets all the requirements. In low-responsibility structures, where it makes sense to think about savings, you can use a cement mortar of the M300 brand. And for the plinths of the facade wall in areas with high humidity Portland cement M500 is more suitable.

The strength of cement increases during curing and reaches a maximum after 28 days. The cement mortar begins to set after 12-15 minutes, and the plaster completely hardens after 11-12 hours.

Lime for addition to a mixture with cement or for independent use is used only in a slaked state. Lime can be mixed in the form of powder (fluff), lime milk (mixture with water in a ratio of 1: 8-10), lime paste. In the latter case, slaked lime is mixed with sand in a ratio of 1:3 and mixed with water until the consistency of a thick dough.

Sand is considered an indispensable aggregate. It easily creates a single structure with cement, lime, gypsum, clay with thorough mixing. In order to ensure high-quality plaster walls with cement mortar, it is best to use sifted river sand of fine and medium grain size. The size of the fractions can be as follows: fine-grained - 0.2-0.5 mm, medium-grained - 0.5-2 mm. The composition of the sand should not contain organic impurities that can cause the process of decay, as well as clay, silt and dirt.

Gypsum is sometimes used in lime-based plasters for interior work. It increases the strength of the lime composition and dramatically reduces the setting time of the solution (up to 5 minutes). The advantage of gypsum as a binder is that it does not shrink after the mortar has set.

Solution proportions

In order to plaster exterior walls and interior walls in wet rooms, a simple plaster is most often used. cement-sand mortar with a ratio of cement and sand 1:3, and water is added until the consistency of thick sour cream is obtained. Such a solution should be used within 1 hour, therefore it is prepared in the appropriate volume. If the plaster is applied inside dry rooms, then a ratio of 1:4 is used, and sometimes 1:5. To increase plasticity and setting time, plaster for external walls can be made from a solution of cement and sand in a ratio of 1: 2 with the addition of lime paste in the form of 0.5 parts of the mixture.

In order to plaster the interior walls or ceiling in 3 layers, the following compositions are recommended (based on a batch of 200 liters of mortar):

For spraying you will need: cement - 30 kg (23 l), sand - 248 kg (155 l), slaked lime - 17 kg (34 l), water - 50-52 l.
For the soil layer: cement - 23 kg (18 l), sand - 255 kg (160 l), slaked lime - 20 kg (40 l), water - 50 l.
Top layer: cement - 16 kg (12 l); sand - 260 kg (165 l); slaked lime - 18 kg (36 l), water - 50 l.

Use of additives

To increase the setting time of the solution, i.e. increasing the duration of use of the finished solution, you can add wood glue, but in a proportion of no more than 2-4%. A similar effect, but with an additional plasticizing property, has a latex adhesive if it is added in an amount of 15-20% of the cement content.

The plasticizing effect has the addition of liquid soap or detergent to the cement mortar. Usually adhere to the proportion of 80-100 g per 10 liters of solution. Before the introduction into the cement mortar detergent mixed with water until a thick foam is formed. Clay can be used as an additional plasticizer. It is pre-mixed in water (alone or with lime).

To obtain a decorative color solution, when applying the outer layer of plaster, you can add a pigment (dye) of the desired color to the mixture. If it is necessary to increase the heat resistance of the plaster (for example, near the stove or in the bath), special refractory clay or fireclay powder is added to the cement-sand mortar. Even the walls of fireplaces can be plastered with such a solution.

Plastering is an integral part of the renovation of our apartments. Unfortunately, walls are rarely perfectly even, so they need to be additional finishing. It is impossible to do without a layer of plaster. Sometimes it takes so much that the costs can cost a tidy sum. In the article we will analyze how to prepare a solution for plastering walls with our own hands.

Plaster remains the most common material for leveling walls. In addition to leveling, it protects the surface of the walls from external influences. It is easy to choose the right composition, some types are suitable for finishing wooden walls, some concrete, just read carefully and choose the one that suits your surface. The manufacturing process is also not difficult, the main thing is to follow the manufacturing instructions.

What are the solutions

Clay;
Lime-gypsum;
Lime;
Cement-lime;
cement;
Terrazitic.

Regardless of the type, the solution should be viscous.
Cement mortars are suitable for indoor and outdoor use. Such a solution is not afraid of moisture, which means that it can be used in a room with high humidity. The cement mixture is the strongest of all, however, the process of its manufacture will take more than 12 hours.

Lime mixtures are afraid of moisture, which means that they can only be used in rooms with moderate humidity. For exterior finish also suitable, but only if the surface will not be constantly exposed to water. To ensure the strength of the composition, gypsum is added. Work with such mixtures should be fast: they will harden in half an hour after manufacturing.

Clay mixtures are used for finishing wooden surfaces. Clay is afraid of water, which means it can only be used in dry rooms or in rooms with normal humidity.

The composition of the plaster should include three components: these are binders for adhesion, filler for strength and water to create the desired consistency. If it is necessary to add some more properties to the characteristics, then a comparable substance can be added.

The surface is plastered in several layers. You need to decide what exactly you are plastering for? If for alignment, then you need the most astringent composition. If you use plaster as a primer, then it should have a medium viscosity. As an atomizer, the presence of binder should be kept to a minimum.
In the manufacture of cement mortar for spraying, the ratio of binder - aggregate is 1: 3, primer 1: 2, and finishing mortar 1: 1.5. Clay mortar implies the presence of aggregate 4 times more than the clay itself. And the lime mortar is twice as much.

What can be added

Lime;
Gypsum;
Liquid soap;
PVA glue.

Lime is added to improve elasticity. In addition, its presence will make the solution less susceptible to moisture.

Gypsum will allow the mortar to harden faster. This is especially true for cement mortar. But don't add too much or it will harden right in the mixing bowl.

Liquid soap adds elasticity and increases adhesion, your solution will be more plastic, and therefore lie on the surface more evenly.
PVA glue will add strength and adhesion to the material. Subsequently, during operation, the solution will not crack.
The most common mortar filler is ordinary sand. Quartz sand is the highest quality, but others will do. Sand must be sieved to remove debris.

Required Tools

Bucket for mixing. Any container will do, as long as it is clean.
Measuring container
Drill or perforator for kneading.
If there is no drill, then a shovel, a strong stick, or anything that can interfere with a heavy mixture, will do. But it will be quite difficult to do it manually.
Binder
Aggregate

If necessary, prepare additional additives to improve the characteristics of the mixture.
How to calculate in what quantities you may need components? Consumption of cement for wall plastering: Calculate the surface area and multiply by the layer of plaster. The width of the minimum layer is 6mm.

If you have curved walls, then the layer will vary in width. Measure all slopes in centimeters, then add them up and divide by the number of slope points. Multiply the resulting number by the area of the curved wall.

Cooking technology

Cement-sand mixture

Very durable and not afraid of moisture. She will last a long time. However, it is the most difficult to work with. It weighs a lot, which makes the process difficult. Complete drying of the mixture may take more than one week.
First, sift the sand through a sieve to get rid of debris. Pour dry cement and sand into the container in a ratio of 1:4. Mix them up. Add water little by little, gradually stirring the mixture. Water must be added until the mixture is homogeneous, resembling sour cream in density. If you want to add special components, then you need to do this at the end. Then stir again. The solution is ready. Since it is infused for a long time, the solution must be immediately made in the right amount. It's even better to cook more than you need.

Mixing cement-lime mortar

Lime is used to increase strength. Sift the sand and mix it with dry cement in a ratio of 4:1. Lime is kneaded in a separate container in the amount of two portions. Dilute the lime with water and mix until a dough forms. Add it to the cement with sand and gradually add water, stirring until a homogeneous mass is formed.

Lime-gypsum mixture

It dries very quickly, you need to work with it almost immediately. Divide the wall into several zones and prepare as much mixture as needed for one zone. Add water to the lime and stir. You should get a dough-like mass. Dilute gypsum with water and stir. Add it, stirring, to the lime.

clay mass

Clay must be wetted before work and covered with a rag. She will insist throughout the day. Then knead the mass. Mix part of the clay with sawdust 1:3. Add water and stir. Sand can be used instead of sawdust. Such a solution can be stored for a long time: all you need to do is simply dilute it with water. For strength, you can add cement, lime will make it more elastic.

Gypsum-based plaster

Depending on the amount of gypsum, such a solution can seize instantly even in a bucket, so keep an eye on the amount of gypsum. Mix chalk and plaster 3:1. You can add some glue. While stirring the mass, add water.

Terrasite mortar

Used for finishing only. Coloring pigments can be added to the composition to obtain the desired color. To obtain a fine-grained mass of red color, you need to use: cement, fluff lime, quartz sand, mica 1: 3: 9: 0.5. Add iron minium at a ratio of 2.5% of the total mass of the mixture.

How to apply plaster

Before application, the surface must be cleaned of the old finish layer. Then wash the surface. Apply a waterproof primer with antibacterial properties to the wall. It is better to apply in two layers, this will increase adhesion, and the surface will be smoother. Apply a new layer until the old one is completely dry. Check with your hand in an inconspicuous area. If the surface is not sticky, then the primer is dry.

Plaster can be applied in several ways:

splashing;
Priming;
Finishing.

Wet the wall before spraying and apply to the surface with a spray bottle. The layer should not exceed half a centimeter for concrete.

The primer solution is thicker, applied with a spatula to the surface. Wait a bit and then level the wall. If cavities are formed, add a little mixture, and if there are bumps, remove it.
Finishing is done with a spatula. The solution is applied in several layers.

Sift the ingredients of the mixture through a sieve in a dry state;
If plaster is used for leveling, then it must be much stronger than the finish;
The mass should be oily, but not too much;
Prepare the cement mortar immediately for full coverage, and the gypsum mortar, on the contrary, in small portions;
Follow the instructions exactly. If a certain order of adding components is indicated, then stick to it, otherwise the composition may subsequently turn out to be of poor quality;
The plaster should not be too plastic, it should stick to the wall without spreading. At the same time, too dry mixture is not allowed, then it will crack.