The correct proportions of mortar for plastering walls

Plaster or a layer of finishing material applied to the surface during construction work is an obligatory stage preceding the finish finish.

This is a specially prepared mortar (mortar), which, after drying, solidifies, forming a firm, even surface, ready for final processing.

In most cases, it is used to level the walls, fix any defects, and also seal technological channels formed during the repair, for example, when laying new wiring. The surface becomes smooth, smooth and aesthetic.

The exact proportions of the mortar for the plaster walls allow the prepared mixture to dry out to fulfill its function and not crumble over time. To properly choose it, you need to have a general idea of the types of building mixtures and their purpose. Knowledge of their main components and application possibilities will allow you to easily navigate the existing assortment and correctly apply the solution for their use.

Kinds of plasters and their features

Wall decoration can be used outside or indoors and is divided into three main types:

• Standard, as protection from external environment (external walls) or correction of surface defects, including leveling, sealing of slots, technological channels and preparation for final finishing with decorative decorative coatings, usually thin-layered;
• Protective, performing the function of an insulator or screen, for example, suppressing noise, retaining heat or preventing penetration of radiation;
• Decorative, used during the finish coat (color, stone, Venetian, graphite).

Each species is characterized by a certain composition, the preparation of which requires an exact proportion of the mortar for the plastering of the walls.

What is a building mix

To prepare mortar for plastering walls, the proportions must include an astringent (cement, lime or gypsum) filler, usually sand and water.

Depending on the amount of binder, they can be:

• Lean, distinguished by the absence of cracks, but a poor fortress;
• Fat, able to crumble and settle down.

Skinny mixture easily slip off the trowel, fatty, on the contrary, stick to it. The task of any builder is to prepare a mortar for the plaster walls, the proportions of which will be optimal.

In addition, a plasticizer is added to the finished solution, which facilitates the work with the mixture. The simplest variant is a usual liquid soap or powder for washing, but there are also special industrial additives.

Number of layers

The application usually occurs in three layers, which have individual proportions of the solution for the plastering of the walls:

• The first (spray) is applied by a layer of at least 5 mm and not more than 9 mm when all the irregularities are filled and similar in appearance to sour cream;
• The second (ground) is the main layer, which can be applied several times and has a density of dough;
• The third (covering), is applied by a layer no more than 4 mm, it is obligatory on a damp surface, on a consistence it is similar to a spray.

When preparing mortar for plastering walls, the proportions differ in the amount of binder, most often cement. In the first layer there is very little of it, in the second it increases and in the third it becomes maximum.

Types of mixtures

When decorating walls, several basic types of compounds are used. Today, basically three mixtures are used:

• Cement, the most common and popular, is characterized by the greatest strength, but a long period of hardening;
• Clay, used during internal and external work when processing wooden surfaces;
• Calcareous, inexpensive analogue of cement mix, often used with gypsum, accelerating the period of hardening and increasing strength.

In addition, depending on the situation, other options may also be used:

• Gypsum - most rarely used because of rapid (within a few minutes) the initial setting and full fixation after half an hour;
• Mixed - characterized by the use of several special components;
• Special - applied with a specific additive depending on the goal.

One of the important indicators determining the type of solution is the humidity level. Depending on the microclimate, the desired composition is selected. The most universal and widespread is cement mortar for plastering walls, the proportions of which are known even to the amateur, and allow it to be used successfully both outside and inside the room.

To better understand, the proportions of the mortar for the plaster of the walls, which are now used in any construction work, will be discussed in detail below.

Cement solution

The most reliable, simple and ubiquitous method. To do it, you must clearly observe the order.

Work begins with the preparation of all components and, first of all, sand. It must be dried, after which it must be sifted. Then carefully clean from all lumps, especially clay. Sand of red or red color is not desirable to use, this lowers the quality of the finished mixture and its performance properties, and it is impossible to use non-sifted and untreated ones.

After sieving, you can start to prepare cement mortar for plastering walls. The proportions vary depending on the type of cement used. For example, applying the grade M400, 4 parts of sand are enough for 1 part of cement. If the M500 is used, the number of parts is increased to five. Violation leads to loss of quality of finish and is not allowed. Dry ingredients are thoroughly mixed in a pre-prepared container. This can be done using a mixer inserted into a puncher, shovel or concrete mixer.

The choice of method depends on the required volume. If you want to work independently, it is enough to use a large construction bucket of 15 or 20 liters, in which you can prepare a solution for plastering the walls with your own hands, the proportions remain the same. If the work is done by several people, it makes sense to use a large trough or a concrete mixer.

In a carefully mixed mixture, gradually add water, bringing the composition to the state of thick sour cream.

Features of the lime mortar

In order to reduce costs, cement is sometimes replaced with hydrated lime, which almost does not affect the quality. Especially since the lime and cement mortar for plaster wall proportions have almost the same.

Its feature is the use of slaked lime only. It's pretty simple to do at home without much expense.

Acquired lime is poured warm, but not hot water in a large container, and after completion of the reaction, filter, usually through gauze. It can be used not earlier than in a day.

Lime mixture

Preparation of the solution also requires consistency.

First lime is cleared of lumps by stirring. The use of water or sand in small quantities is permitted. Having received a uniform composition, you can proceed to prepare the mixture.

The required composition is obtained if one sand is placed on one part of the lime mass, previously sieved and purified. Along with the sand, water is gradually introduced. This continues until the solution looks like a thick, homogeneous mass. After which it can be used for 12 hours.

Features of the lime mortar during outdoor work

Usually a calcareous mixture is used only in a dry climate. If the time for processing the facade is limited, the proportion of the mortar for the plaster of the outer walls includes a small amount of gypsum.

This allows you to start to freeze it for several minutes, completely hardening in half an hour.

To make a solution, add 1 kg of gypsum to 3 liters of the finished lime mixture. But it is necessary to take into account the term of solidification and the amount of work, otherwise it will harden ahead of time.

Clay mortar

The use of clay is still quite common in wooden houses. To prepare a strong clay mortar for plastering walls, the proportions should include cement, lime or gypsum.

It will take alumina, preferably greasy, which is soaked for several hours. The mixture is important to constantly mix and add water until it becomes thick.

The easiest way to prepare is to add sieved sand in a one to three ratio. But it is not very strong. This is corrected by adding to these constituents 1/5 of the cement. At the same time, cement and clay are first mixed, that is, binders, and only then sand.

Sometimes cement is replaced with lime, but with a mandatory increase in the part to 1/2. You can also add gypsum, but not more than 1/4.

Ratio of components

The proportions of different components in the finished solution are always different, depending on the task and the type of layer. Typical relationships are shown in the table below.

Solution	Ratio of components (in parts)
	First	Second	The third
Cement-sand	13	1 - 0.2 - 3	12
Lime - sand	13	13	12
Lime - sand	14	14	-
Lime - clay - sand	0.2 - 1 - 3	0.2 - 1 - 5	0.2 - 1 - 3
Lime-gypsum-sand	1 - 1 - 2	1 - 0.5 - 2	1 - 1 - 5
Clay - gypsum - sand	1 - 0.2 - 3	1 - 0.2 - 3	-

These proportions are not constant and can be adjusted in each individual case.

Ready-made dry mixes

Today, almost all manufacturers provide a wide range of ready-mixed dry mixes. All that is necessary before starting work is to take the necessary volume of water and ready-made dry mortar, after which everything is thoroughly mixed, usually two times. The mixture is ready for use. As a rule, they are always slightly more expensive than the cost of incoming components, if they are purchased separately.

Their main advantage is that there is no need to mix several different elements in the right proportions. In addition, the sale of bulk materials is carried out in large batches, which is not always convenient. For example, it makes no sense to purchase a bag of cement weighing 25 kg, if you need to seal a small hole in the wall. Therefore, with a small amount of work, the finished dry mix will be a good alternative.

Work with plaster

Properly selected proportions of mortar for plastering interior walls or exterior are one of the key moments of any repair. But even an ideal ratio will be useless if plastering is carried out with a violation of the application rules on the surface. Therefore, it is necessary to pay attention to all stages without exception. Only in this case we can expect a positive effect.

The sequence, thickness and number of layers has the same meaning as the composition. The error can lead to the most unpleasant consequences. The application is made by a special tool, with a mandatory time interval provided for each type of mixture.

With minimal experience in carrying out such work, it is recommended that a compulsory number of trial attempts be made in small plots to assess their own capabilities.

Tools and specificity of individual surfaces

If the work is done by yourself, you will need a certain building tool:

• Rule;
• Master OK;
• level;
• Spatulas of different sizes;
• cord;
• Grater for grouting.

The application of the first and second layer is performed by the trowel, the third by the trowel. Typically, the first layers are applied to the reinforcement mesh. When applying the finishing coat, a gypsum mixture is used.

Surfaces with large differences are treated using special construction beacons that facilitate the application and leveling of plaster.