Cement-based plaster mortar for walls. Calculation of cement per cube of mortar How much sand is in a cube of mortar

To determine how much sand and cement is needed per 1 cubic meter of mortar, it is important to know its purpose. To prepare masonry, plaster, foundation and other types of mixtures, different ratios of dry materials are used. The consumption of sand and cement per 1 m3 of mortar varies for each type of work, and often other dry or liquid formulations, increasing moisture resistance, strength, changing the rate of hardening of the mixture, etc.

What determines cement consumption for different solutions?

Preparation cement mortar, the proportions of which may differ, require strict adherence to technology and the correct determination of the ratio of components. For concrete application different brands Varying amounts of cement and sand are used. Remembering the proportions of cement and sand is not enough for high-quality construction; it is better to understand the principle.

Requires strict adherence to the technology for preparing cement mortar

Main factors influencing consumption:

the amount of fillers in the mixture. The greater the proportion of crushed stone and sand, the higher the cement consumption per 1 m3 of solution. Cement is the binder of the components, which is responsible for holding all the fillers together. The ratio of bulk mixtures determines the amount of cement;
brand of cement. As the grade increases, the strength of the final structure increases. It is worth remembering that the grade of the final mixture is significantly lower than dry cement, since sand is added to the composition, and gravel or slag can also be added;
brand of solution. The cement-sand mortar is also divided by grade. For all types of work, GOST has recommended brands. After determining the desired brand construction mixture, you can choose the right brand of cement. For example, to obtain an M100 mixture from M500 cement, you will need to mix 1 part Portland cement, 5.8 parts sand and 8.1 parts crushed stone. If the final goal is M450 solution, a proportion of M500 cement (C:P:SH) will be required: 1:1.4:2.9;

The density of cement plays a secondary role here, since it directly depends on the brand of cement, but it is necessary to know it during the calculation process.

Conclusion: how much cement is required per 1 m3 of solution depends on the required strength mortar and brand of the original mixture.

The density of cement directly depends on the brand of cement

Types and brands of mixtures

The introduction of the concept of “cement grade” helps to calculate the cement consumption per cube of mortar if the input parameters are known. To prepare a solution with the same construction characteristics from different brands cement mixture, different proportions of fillers will be required. Cement is produced in production, starting from grade M100, but due to the low structural strength, the material is practically not used.

The most popular cements are M400 and M500, but some other types have also become widespread. The choice of mixture depends on the scope of application of the material.

The main areas of use of cement grade:

M300 cement is used in installation construction, as well as during the manufacture of monolithic structures;
M400 cement is successfully used in monolithic construction and during the preparation of reinforced concrete;
M500 cement is actively used in the construction of buildings or slabs that must be resistant to moisture or located in water. Areas of application of this concrete mixture are quite wide: the creation of sidewalks, the construction of asbestos-cement structures, the formation of large concrete masses and all kinds of foundations;

M400 and M500 cements are the most popular

M600 cement is used to create prefabricated structures and foundations that are subject to high loads;
M700 is a suitable grade of cement for the construction of highly loaded and stressed structures.

Material consumption rates per cubic meter of different solutions

Today there are 4 main areas of use of concrete: foundation, masonry, screed and plaster. In each case, the building mixture is subject to special requirements, which makes the choice of cement and its consumption different. The greatest consumption of cement per cube of concrete occurs when it is necessary to make masonry or plaster. The consumption of materials per 1 m3 of foundation mortar is slightly lower due to the use of a large filler fraction: slag, crushed stone or gravel.

GOST has records of cement consumption rates per 1m3 of mortar, taking into account the purpose of the mortar. Designation of concrete per cubic meter. meters is a generally accepted system of measurement.

Cement consumption rates per 1m3 of solution

Consumption standards per 1 m3 using M500 cement:

on M100 – 170 kg;
on M150 – 200 kg;
on M200 – 240 kg;
on M250 - 300 kg;
on M300 – 350 kg;
on M400 – 400 kg;
on M500 – 450 kg.

Consumption rates for cement and sand per cube of foundation mortar

Calculation of cement for foundation calculator is the simplest way understand how much material is required and the number of necessary components. Concrete calculations can be done using high accuracy and manually.

To determine how much cement is needed per 1 m3 of solution, we recommend following simple instructions:

Cement consumption rates for foundations

We determine the appropriate brand of cement mortar. Usually, when creating a foundation, it is advisable to use a solution of M100-M300. For low-level buildings, M100 is sufficient, if you plan to build several floors - M150, and M200 and higher is used in the construction of multi-story buildings and any structures that have increased strength requirements. If the foundation is built under wooden building, an M50 solution is sufficient.
We select the brand of cement. For standard tasks, M300-M400 is suitable in the proportion of cement to sand 1 to 3. When using cement M500 - 1 to 5.

How many kg of cement in 1 m3 of solution:

in M50 when using M400 – 380 kg;
in M100 when preparing concrete from M300 cement – 214 kg;
in M200 with cement M400 – 286 kg;
in M300 at M500 – 382 kg.

The data is presented if the cube contains 2-4 parts of sand and 3 parts of crushed stone.

Consumption rates of cement and sand per cube of masonry mortar

To prepare cement mortar for wall construction, a proportion of 1 to 4 is most often used. Thus, the cement consumption per cubic meter will be 0.25 m3 or 325 kg, and the sand consumption per 1 m3 of mortar will be 0.75 m3 or 1200 kg.

Cement consumption rates for masonry

Table 1: Mortar consumption for walls of different thicknesses

To calculate how many bags of cement are needed, just multiply 325 kg by the consumption per cubic meter, for example, walls of one brick - 0.221. You will get 72 kg of cement for laying 1 m3 of wall, provided that the composition does not contain other components (lime, clay, etc.).

Consumption rates of cement and sand per cube of screed mortar

Cement consumption per 1 cubic meter of solution is calculated according to similar rules as in previous mixtures. The recommended mixing ratio is 1 to 3. Difficulties in calculations often appear at the stage of determining the volume of the solution, so let’s consider clear example. It is necessary to fill a surface of 3x4 m or 12 m2. The layer thickness will be 30 mm.

Cement consumption rates for screed

Calculation of cement for screed from the example:

We calculate the required volume of solution: 12 m2 * 0.03 m = 0.36 m3.
We determine the brand of cement, M200 solution is often used, and we use it as an example. We will cook from M500, and according to the standards, the consumption will be 410 kg.
We calculate the required number of bags of cement: 410 kg * 0.36 m3 = 148 kg - this is 6 small or 3 standard bags of 50 kg each.
We determine the cost of sand. To do this we multiply specific gravity 1 m3 of sand for the required amount of the finished mixture: 1600 kg/m3 * 0.36 m3 = 576 kg, and since the share of sand in the total solution is 75%, we also multiply by 0.75 - 432 kg of sand. Sand consumption per 1 cubic meter of solution is approximately 1200 kg/m3.

Consumption rates of cement and sand per cube of plaster mortar

Cement consumption per 1 m2 of plaster greatly depends on the quality of the wall covering, required thickness layer and number of large holes. Again, for clarity, we will give an example of the calculation, remembering that a mixture of 1 to 4 is usually used. Input parameters: it is necessary to cover 60 m2 of walls with plaster 2.5 cm thick.

Calculations of cement and sand consumption per 1 m3:

Amount of materials in cubes. For 1 m2 you will need 1 * 0.025 = 0.025 m3 of solution, where a fifth is cement and the rest is sand. Using elementary mathematics, we determine that 0.02 m3 of sand and 0.005 m3 of cement will be required.
For the entire area of the wall you will need: 0.02 * 60 = 1.2 m3 of sand and 0.005 * 60 = 0.3 m3 of cement.
The specific density of cement is on average 1400 kg/m3 (fresh 1100-1200 kg/m3, and compacted 1500-1600 kg/m3). We determine the cement consumption: 0.3 * 1400 = 350 kg.
Required weight of sand: 1.2 * 1600 = 1920 kg, we remind you that 1600 kg/m3 is the specific gravity of sand.

All calculations are simple; it is only important to choose the right brand of the initial mixture and the desired brand of output solution. Everything else can be easily calculated in a few mathematical steps.

From the correct calculation of the required number building materials The pace of construction also depends. And if, for example, it does not cause any particular difficulties, then determining the cement consumption per cube of mortar can create certain difficulties.

How much cement will be needed per cube of mortar - what will be the consumption?

Determining how much cement is in a cube of mortar is quite simple. To do this, you need to know the ratio of aggregate and binder, as well as the density of cement (it is 1300 kg/m3). If a binder to filler ratio of 1:4 is used, then composition mortar mixture there will be 20% cement. Considering its density, cement consumption per cube of solution will be 1300/5 = 260 kg (5 or so bags). The required amount of binder can also be calculated using special online calculators.

It is important to remember that the ratio of binder and aggregate is indicated in volumetric form; when calculating the number of bags of cement, you need to convert these values into kilograms, taking into account the density of the material.

The easiest way is to determine how much cement will be used per cube of foundation mortar. To do this, you just need to calculate the total volume of the foundation (in m3). Then determine the volume of binder required to prepare a cube of concrete and calculate the total need for cement.

If it is necessary to determine the amount of cement for laying walls, the task becomes more complicated, since it is necessary to take into account the thickness of the mortar joint when calculating. To simplify calculations, use the average consumption of the solution for a cube of masonry. Practice has shown that about 0.25 - 0.3 m 3 of solution is consumed per cube of masonry. Therefore, when determining how much cement is per cube of masonry, it is first necessary to determine the volume of the building walls.

It has been experimentally confirmed that the amount of mortar per 1 m 3 of facing masonry ceramic bricks 13% higher than the required amount of mortar for laying other types of bricks.

From correct counting required quantity The entire construction as a whole depends on the binder. In case of an error, the construction process can stall at the most crucial moment.

What affects cement consumption when making mortar?

When selecting the composition of the mixture, you need to remember that as the grade of cement increases, the need for binder decreases. In some cases, in order to maintain the structure of the mortar after setting, stone dust is introduced into it.

Cement consumption per cube of mortar depends on:

type of solution. Depending on the purpose, sand, lime and clay mortars can be used in construction. For each of these solutions, the ratio of binder and aggregate differs. So, in order to prepare a cement-sand mortar, cement and sand are taken in a ratio of 1:3, 1:4. For lime - cement is added in a ratio of 1:3 to lime mortar. When using clay, cement consumption per cube of mortar is entered based on the calculation of 1:9;

(determines the strength of the frozen mixture). The brand of mortar is selected depending on which element of the building it will be used in. For the foundation and load-bearing walls The strength of the masonry is of decisive importance, so it is recommended to use the most durable mortars. For interior walls mixtures with less cement consumption can be used. For plastering walls, you can use mixtures with a lower cement content;
composition of the solution– selected ratio of binder and filler.

There is a direct relationship between the brand of mortar and the cement content in the mixture. The brand of mortar depending on the cement content in the mixture is shown in the table.

Brand of solution	in solution, kg
M10	81
M25	133
M50	178
M75	245
M100	306
M150	414
M200	510

The values of cement content in the mixture given in the table are valid for 1 m 3 of solution.

Depending on the required brand of mortar, the classes of cement used, as well as the ratio of binder and filler, vary.

Plastering walls and ceilings is important stage finishing works. Facing coating performs the functions of protection, decoration and additional insulation, perfectly hides seam joints and corrects minor masonry defects. Strength and durability depend on the correct ratio of the components of the solution.

The basic composition of any plaster always remains the same: binder, filler and water. The choice of binder depends on the nature of the finishing work (external/internal) and operating conditions (wet/dry microclimate). It can be cement, clay, lime, gypsum. Quarry or river sand is most often used as a filler. Sawdust, perlite, fine slag, and granulated polystyrene are less common. The filler ensures the strength and smoothness of the layer.

In practice, cement mortars are most often chosen for finishing external and internal walls; they are characterized by increased strength and durability. Technological feature is a slow (about 12 hours) setting. To change quality characteristics it is combined with other binders. The proportions of the main elements in the composition of the plaster determine its performance indicators.

Pour in pre-sifted dry sand. To clear it of pebbles and shells, you need to use a sieve with small cells. For primer plaster walls, a diameter of 2-3 mm is suitable, for finishing– no more than 1 mm.
Add cement and mix everything thoroughly. It is very important that the sand is well dried, then it combines evenly with the cement, does not burden it and prevents the formation of lumps.
Pour in water. First add no more than 2/3 of the total volume. Add the rest gradually, achieving homogeneity of the mass.

The prepared solution must be used within an hour. Left unspent, it begins to harden. If you add more water, you can restore elasticity, but the quality will be worse.

2. Cement-lime plaster.

Can be prepared in two ways:

Mix lime paste with sand and add cement to it. Stirring constantly, add water little by little to the desired consistency.
Cement and dry sand. Prepare lime milk by combining water with lime dough in a 1:1 ratio. Dilute the sand-cement mixture with milk.

3. Cement-clay.

Wet the lumps of clay with water and cover them with a thick rag.
Mix the swollen clay with sawdust in a ratio of 1:3.
Adding water little by little, bring to the required density.
To enhance the strength, add dry cement to the composition and mix thoroughly.

Solution consumption

The smaller building elements, the more seam joints in the masonry. This directly affects the unevenness of the walls. Deviations from the level can be both vertical and horizontal. Leveling highly curved surfaces will require a lot of compound. To calculate its consumption per 1 square meter, you need to multiply the thickness of the layer and the area of the walls.

To obtain curvature data, it is convenient to use a beacon. In that case minimum thickness plaster will be 6 mm. This slightly increases consumption, but all surfaces reach an ideal level.

To find out the maximum value of curvature, it is necessary to hang the walls in several places. How more dimensions, the more accurate the calculations will be. For example, deviations of 10, 15 and 40 mm were found. These parameters need to be added up and the sum divided by the number of measurements: (10+15+40)/3=22 mm. The result is an average thickness of the plaster. Now all that remains is to multiply it by the area of the working surface.

For those developers who prefer to use ready-made solution in dry form, making calculations easier. On back side packaging manufacturers themselves indicate the exact consumption of material. With a layer thickness of 10 mm, approximately 10 kg of mixture per square wall is required.

Can be considered the most popular and popular material in modern construction. Its strength characteristics will depend on the quality and ratio of the ingredients used. Proportions and composition are determined by the destination area. Concrete is most often used to construct foundations. The pace of construction will depend on how correctly the required amount of building materials can be determined. And if calculating the required volume of bricks, as a rule, does not cause difficulties, then determining the consumption of cement that goes into 1 cubic meter of mortar can create some difficulties.

What affects the volume of cement when preparing a cube of mortar?

When selecting the composition of the mixture, it is necessary to remember that with an increase the need for using a binder will be reduced. In some cases, in order to maintain the structure of the mixture after setting, stone dust is added to it. In order to decide on the question of how much cement is in 1 cube of solution, you need to remember that the consumption of the mentioned ingredient depends on the type of mixture. Depending on the purpose, clay, sand or lime mortars can be used. Each of these compositions uses its own ratio of aggregate and binder. Thus, in order to obtain a solution of cement and sand, the mentioned components are taken in a ratio of 1:3 or 1:4. To receive lime mortar cement must be introduced in a ratio of 1 to 3 in relation to the lime component. When using clay, the volume of cement per 1 cubic meter of solution changes, and you need to use a proportion of 1:9.

Cement consumption depending on the brand of mortar

The brand of the mixture determines the strength of the composition after hardening. This indicator is selected depending on the structural element construction mortar will be used. For example, for load-bearing walls and foundations, the determining value is the strength of the masonry. For this reason, it is recommended to use solutions that are as strong as possible. If you are wondering how much cement is in 1 cube of mortar, then you need to remember that for internal walls it is permissible to use a mixture with a less impressive volume of cement. For plastering, you can also use solutions with a lower cement content.

Dependence of the brand of mortar on the volume of cement

If you are faced with the question of how much cement is in 1 cube of mortar, then you need to remember that the brand of mortar depends on the volume of cement used. Thus, to obtain a solution of grade M10 cement for the mentioned volume, 81 kilograms must be added. M25 will be obtained if you add 133 kilograms of binder. For the M50, 178 kilograms must be prepared, while for the M75 - 245 kilograms. If you are faced with the question of how much cement is in 1 cubic meter of M100 brand mortar, then it is worth noting that these ingredients must be used in a volume equal to 306 kilograms. For the highest and M200, it is necessary to add cement in quantities of 414 and 510 kilograms, respectively. Once you know how much cement is needed per 1 cubic meter of mortar, you can begin purchasing the components to carry out the work.

How much cement should I add per 1 cubic meter of mortar?

It will be quite easy for the master to determine how much cement is needed per 1 cubic meter of mortar. To do this, it is necessary to take as a basis a certain ratio of aggregate and binder, as well as the last figure is 1300 kilograms per cubic meter. If the proportion of cement and aggregate is 1 to 4, then the composition will contain 20% binder. Taking into account the density, the consumption of this ingredient per cubic meter will be: 1300/5 = 260 kilograms. When you visit the store, you will need to purchase 6 bags, since you will need 5 or so bags. In this way, you can always calculate the amount of binder yourself.

Cooking instructions

Once you know how much cement is needed for 1 cubic meter of mortar, you can move on to the theoretical question, namely, familiarization with the preparation technology. The solution should be mixed using a concrete mixer, metal bath or in wooden box, depending on what equipment you have available. First you need to mix the dry ingredients, including gravel, sand and cement. Once all the ingredients are well mixed, you can start adding water. At the same time, do not stop stirring. Pouring concrete must be completed within 2 hours after preparing the composition. As soon as the base is filled, care must be taken to eliminate excess air bubbles using a deep vibrator.

Once you have decided how much cement is needed for 1 cubic meter of mortar, you can begin to prepare the necessary equipment and materials. Filling must be done in warm time year. However, if there is a need to carry out manipulations at sub-zero temperatures, then special substances can be added that help concrete gain strength under difficult conditions.

However, the master must be aware that under weather conditions characterized by sub-zero temperature, the work will be difficult. You will have to heat the water, which will prevent the mixture from freezing. If ice is allowed to form, this may cause an increase in the volume of the solution, which, in turn, can lead to destruction of the structure from the inside.

What volume of mortar is obtained from one bag of cement?

If you have 1 bag of cement, how many cubes of mortar will be produced from it? Using this volume, you will get 0.24 cubic meters of sand and cement solution, and you need to use a ratio of one to three. You will need to add one part of clay to the ingredients. Increase the volume of solution to 0.25 cubic meters it will work if you use cement grade M300. Ultimately, it will be possible to obtain a solution

Conclusion

Work on the preparation of cement mortar must be carried out in compliance with the proportions. The correct ratio will allow you to obtain a high-quality composition that will be durable and frost-resistant. It is important not only to prepare the mixture correctly, following the technology, but also to monitor the hardening stage. At the same time, the surface of the structure must be moistened, which is especially important in hot weather. In this case, you can cover the surface with moistened burlap.

During interior decoration buildings often use plaster based on a cement binder solution. To get a high-quality solution, you need to know how much cement and sand is needed for plaster. It is best to purchase cement in bags to make it easier to make proportions. Depending on the need and service conditions, components are added to the cement mortar that will impart certain properties to the resulting mortar:

plastic;
frost resistance;
heat resistance;
resistance to aggressive environments;
slow or fast setting.

If the question is how much cement is needed to plaster walls, then it all depends on what kind of solution is needed. As a rule, from 1 to 6 parts of sand are taken for 1 part of cement. The solution is divided according to the amount of sand taken into the part of cement: fatty, thin and normal.

A greasy solution is obtained if the amount of cement is very large. This solution has strong shrinkage and cracks easily (1-3 parts of sand). Skinny ones, on the contrary, have an increased amount of sand per part of the concrete, they do not shrink and do not crack (6=< частей песка). Нормальные растворы имеют оптимальное соотношение заполнителя и вяжущего(4-5 части песка).

What proportions are they usually diluted in?

When using grade 400 cement, a solution is most often made with a ratio of 1 part cement to 4 parts sand. If you are interested in how much sand is needed in cement 500, then you need to add 5 parts of sand to 1 part of cement. It’s very easy to remember the values: for 400, 4 parts sand, for 500, 5 parts to 1 part concrete. At the same time, to obtain a high-quality solution, one must not forget to take into account that one year of storage: - 100 to the brand of cement. Many people forget about this property of cement.

Screed

If the question is asked - how much sand and cement is needed for a screed, then they mainly use grade 400 cement. The ratio of cement and sand is 1:4. The cement consumption for flooring is determined as follows: for a screed of 1 meter square and 10 cm high, one 50-kilogram M400 bag and 200 kilograms of sand are used. Calculation of the required amount of screed is done using the formula:

(Screed area, let’s say 20 m2) * (screed height, and it is translated in meters, and 10 cm = 0.1 m) = volume required solution.

To calculate the required amount of sand and cement, it is necessary to divide the volume of the required solution by the number of parts (in this case there are 5) and multiply them by the average weight of a cube of material. For cement, this value is 1300 kg; if the exact weight of sand is not known, then the value is 1625 kg. Shrinkage also occurs in the amount of ¼ of the solution, and the resulting values will need to be multiplied by 1¼.

Due to the fact that plaster performs two functions - decorative and leveling, the calculation of the number of components, including cement, must be done separately in each specific case. Experts recommend a “wall-to-wall” calculation based on the so-called “average thickness of the plaster layer.”

Technology for determining the “average thickness of the plaster layer”

So-called “key points” or “beacons” are attached over the entire area of the wall to be plastered, which are set according to the level. These can be nails, self-tapping screws, screws or special strips. The rule here is “the more beacons, the more accurate the calculation.” In general, there should be at least three “key points” located over the entire wall area.

Linear measurements of the depths of the recesses are made, which in one place of the wall can be 5 cm, in another 2 cm, and in a third 6 cm. The measurements of irregularities are summed up, after which their average value is calculated.

An example of calculating the “average thickness of the plaster layer”

Let's say you mounted 15 beacons on the wall and set them level or plumb. Next, we measured and summed up the values of the unevenness - we got a figure of 67 cm. That’s it, we can determine the “average thickness of the plaster layer”: 67:15 = 4.46 cm or 0.0446 m.

Example calculation of plaster mortar consumption per 1 m2 of wall

In order to find out how much cement will be used for 1 m2 of plaster, you must first calculate the consumption of plaster mortar per 1 m2. We calculate the average thickness: 1mx1mx0.0446m=0.0446 m3 Thus, to plaster 1 m2 of wall, 0.0446 m3 of ready-made mortar will be required.

Example calculation of cement consumption per 1 m2 of plastered wall

As is known, the composition of a standard plaster mortar includes cement (M400 or M500), sand and water. At the same time, for M400 cement the proportions of binder and sand for mixing plaster mortar are 1:4, and for M500 cement – 1:5. Based on the given proportions and the average cement density of 1300 kg/m3, the amount of cement can be calculated.

For cement grade M400

0.0446:4=0.01115 m3 (volume of cement per 1 m2). For the convenience of further calculations, we will reduce m3 to kg;
1:1300=0.000769 m3 (volume occupied by 1 kilogram of cement);
0.01115:0.000769=14.5 kg (the number of kilograms of M400 cement required for plastering 1 m2 of wall).

For cement grade M500

0.0446:5=0.00892 m3;
0.00892:0.000769=11.6 kg (the number of kilograms of M500 cement required for plastering 1 m2 of wall).

When performed independently repair work you need to be able to correctly calculate the consumption of building materials. This will help you save money when purchasing them. Cement consumption per 1 m2 of plaster depends on the quality of the surface on which we will apply the solution, technical characteristics mixture and texture of the resulting coating.

Let's consider how to independently determine the mixture consumption depending on the thickness of the layer and the type of plaster used.

Types of cement mortars for plaster

Plaster mixtures used for wall finishing differ in the presence of certain components and their ratio. Divided into types:

Cement - sand	Used for roughing internal and exterior finishing The result is a durable, moisture-resistant coating. Suitable for finishing walls, ceilings in unheated, damp rooms and for cladding facades. The constituent components are cement and various fillers: sand, plasticizers, etc.	The standard solution is prepared in a ratio of sand and cement 1:3. Cement grade M 400 can be diluted 1 part to 8 parts sand. M 100 is mixed in a ratio of 1:2. The composition is selected depending on the type of surface, layer thickness, and operating conditions. To increase plasticity, add PVA glue to the finished mixture in a ratio of 50-100 ml per 10 liters of the finished solution.
Cement-lime	They have good adhesion to all types of surfaces. Used for finishing plinths, cornices made of stone and wood. Lime has bactericidal properties and protects the surface from mold and fungal infections.	1 part cement and lime to 5 parts sand. For a 25 kg bag of cement we take 21 kg of lime, 280 kg of sand, 50 liters of water.

The cement composition is most often used for rough finishing of walls. Thin layer cracks during operation, therefore it is recommended to apply cement-sand mortars with a thickness of 3 to 6 cm, depending on the material from which the walls are made and the technology used for applying plaster.

What affects material consumption

The amount of solution depends on the level of the walls. The more defects, the more mixture required

You can easily calculate the cement consumption for plastering walls yourself. Consumption is determined based on the following components:

type of solution and its components;
how much smooth walls, and what material they are made of.

IN multi-storey buildings the plane deviation in level is 2-2.5 cm. The greater the unevenness of the surface, the thicker the layer will have to be applied.

To reduce the consumption of the plaster mixture, the surface is treated with a primer in several layers. It helps remove dust from the surface, reduce absorbency and better adhesion materials.

At the junction of two surfaces made of various materials, we install the construction mesh. Because of this, a thicker layer of plaster is required. Flow calculation decorative plaster produced using a special technique.

In old houses you can find perfectly straight walls, but more often they have crooked walls.

Calculate the layer thickness

We determine the difference in the surface relative to the vertical plane using a plumb line or installing beacons.

Methods for determining the curvature of walls:

We lower the plumb line from the ceiling, find the most protruding point of the wall, then measure the depth of the depressions.
We use long, even slats as beacons; we apply them to the wall and see how crooked it is; We measure the depressions on the wall.

For clarity, we give an example of calculating the layer thickness cement plaster for a wall of 12 sq. m.

We add up the depths of the depressions on the walls and divide the resulting result by the number of beacons: (2+3+4+5): 4= 3.5 cm. The thickness of the plaster layer will be equal to 3.5 cm.

Standard consumption rates

One bag 25 kg

The average consumption of cement for plaster is indicated on the packaging, taking into account a layer of 10 mm, and is individual for each manufacturer. If we apply a solution 2 cm thick, then multiply the amount by 2, etc. For plaster average consumption is 8.5 kg per sq.m.

If we take a 25 kg bag, then 8.5:25 = 0.34% of the amount of the bag will spread the plaster per 1 m2.

Let us consider in the table the calculation of cement consumption for plastering walls depending on the thickness of the applied layer at a standard consumption rate of 8.5 kg per square meter. m:

Marble chips give the “Bark Beetle” mixture a relief

Composition for finishing plaster The bark beetle contains marble chips, which results in a relief surface with an interesting structure. Standard consumption ranges from 2.5 to 4 kg. Each manufacturer indicates these indicators on the label.

Venetian plaster is applied in a layer of several millimeters, resulting in a small mixture consumption of 70 to 200 grams per square meter. m. Working with such material requires experience; in order to apply it to the surface efficiently, it is better to invite a professional.

Gypsum compositions are consumed in a ratio of 9 kg per square meter. m. The plaster quantity calculator on our website will help you quickly calculate how much of this material will be needed for finishing work.

When purchasing a plaster mixture, you need to add 10% to the calculated amount of material so that you don’t have to run to the store during the work.

We plaster with our own hands

Apply three layers of plaster

After calculating required quantity materials and purchased dry components, we begin to carry out the work.

Step by step instructions:

We prepare the surface. We clean the wall from dust and flaking building materials. We remove rust and oil stains.
We prime the surface in 2-3 layers, applying each subsequent layer after the previous one has dried.
Apply the plaster in three layers. First of all, spray a solution of medium consistency onto the wall; this can be done with your hands, a spatula, or poured from a ladle. Then we rub the composition over the surface using a rule or a grater: apply 4-5 mm thick to a concrete surface, up to 7 mm to a brick surface, and up to 10 mm to wood.
The second layer is the main one. Mix the solution a little thicker than for spraying. Using a spatula or trowel, apply the composition to the wall and rub it over the surface, leveling it.
Apply the last layer with a thickness of no more than 4 mm, and prepare a more liquid solution for it. Apply the coating to the moistened base layer. After setting, but before the surface dries, we grout. Read more about plastering works oh, without beacons, watch this video:

A type of wall plaster is beacon finishing, which allows you to create a perfectly flat surface.

The guides are installed strictly according to the level at a distance slightly less from each other than the width of the rule. Beacons can remain in the wall or be removable.

Rule from the bottom up

Stages of applying plaster to lighthouses:

We fill the area between the beacons with a solution and level it using the rule. We fill all the voids and carefully level them.
We cover and rub the surface well.

We need to prepare such a volume of solution that we can apply it before it hardens.

Be sure to study the calculations of plaster consumption before starting work.

Repair is not complete without leveling the walls and performing plastering work. Processed cement composition the surface serves reliable basis for finishing.

In order not to make mistakes when purchasing materials when self-repair or control the builders, you need to know how much material is being consumed. After studying this article, you can easily calculate these indicators.

Finishing work always begins with correcting problems with the walls using plaster “add-ons”. In each specific case for effective use In order to achieve the maximum potential of plaster, it is important to maintain the correct proportions of cement and sand mortar. You can save money and try to prepare a mortar for plaster from the remains of the masonry composition, or you can make a mixture according to science, maintain the required proportions of cement and sand, then the mortar will last a long time and be strong.

Sand-cement mixture from the remains of masonry mortar

For masonry, a mixture of sand and binder cement is used in standard proportions with the addition of a small proportion of lime or clay. Bricks in masonry are knitted using a standard proportion: 400 grade cement take a bucket with 4 buckets of sand, for 500 grade sand put more in a bucket. Depending on the proportion of lime or clay, the composition becomes rigid and more plastic. This is extremely important for retention brickwork in a vertical position.

Let’s make a reservation right away: the remains of the masonry mixture in its original form are not very suitable for plastering walls for a number of reasons:

The proportions of the plaster mortar have a higher cement content, with a minimized amount of lime or clay;
By the time plastering work begins, the remains of the masonry mortar will have partially lost their plasticity and will give poor adhesion to the surface of the brickwork, and concrete surface such a mixture will not stick at all without special adhesive additives.

Advice! Use the remains of the masonry mortar to adjust the filling of the joints and do not try to adjust its proportions to the values of the plaster mortar by adding cement or sand.

Basics and proportions for preparing solutions

A plaster composition based on a mixture of sand and cement must be prepared and used as soon as possible, before the partial bonding process begins. free water cement grain. You can buy ready-made plaster mixture for the most different options plaster, which has already been selected optimal proportions sand and cement.

The most a good option The situation is considered if you manage to outbid at a serious construction site several bags from a large proven batch of mixtures, not very old and proven in practice. The same goes for buying cement. The most problematic from a quality point of view is considered to be the use of old packaged or hung building materials. In this case, the recommended proportions of cement-sand 1:3 need to be adjusted and a couple of practical test batches done. Most often, grade 400 ShPTs or PTs is used in plaster.

To carry out work to correct defects in the geometry and curvature of walls, use PC I cement mortar with a sand/cement ratio of 3:1 as a masonry primer. For mortar for the main leveling mass of plaster, grade 400 - PC II with a proportion increased to a ratio of 5:1.

Choosing sand for the solution

Sand requirements for plaster composition higher than for the masonry option:

The sand must be sifted and washed; it is extremely important to obtain large and medium sand fractions and eliminate dust and clay inclusions.
The larger the sand fraction, the better the adhesion to the wall, and the harder the plaster becomes. If there is nothing but coarse sand, you can add a small amount (up to 5%) of fatty clay, ground to a fine powder. With more high content clay or the presence of clay lumps in the mixture, a network of small cracks may form on the surface of the plaster.
An excessively fine sand fraction can make the plaster solution too plastic and slippery, does not hold the applied layer well, and floats. The recommended maximum layer on such sand is, as a rule, no more than 3 mm; it is excellent for finishing surface finishing work.

Important! In the preparation of plaster, only dry sand is used; even a slightly moistened mixture with cement mixes very poorly with dry cement, the material will be heterogeneous, and, as a result, the surface of the plaster will crumble and crumble in places.

The most used cement grades in plastering

Depending on the goals and objectives, Portland cements or Portland slag cements of a grade not lower than 400 are used for plaster mortar, and less often, in special cases, grade 500. Most craftsmen are well aware of the preparation technique and the required proportions of the solution, the requirements for sand and cement, but they cannot always successfully select the required brand for specific types of plaster or working conditions.

For large areas of plastering work, with a small amount of corrections or leveling of walls, Portland M400 type 1 is used; on the packaging marking after the letters PTs you can see the designation I or II. The first is the cement with the maximum rate of increase in hardness and rigidity. The listed cements have proven themselves well for plastering external walls, in conditions high humidity and low temperature.

The second type of cement corresponds to Portland with special additives that reduce the internal stresses of concrete and cement castings, improve the ductility and frost resistance of the plaster composition. This cement is well suited for leveling walls.

In addition, there are many specialized grades of cement with improved characteristics, but they are used in industrial structures and are most often not used for ordinary plastering work.

Use of special modifying additives

It is not always possible to achieve high-quality “adhesion” of the plaster mixture to brick or, especially, concrete base walls Often the cause of abnormal adhesion is the incorrect consistency of the prepared plaster mass or poor preparation of the wall surface itself. Checking the consistency of the plaster composition is quite simple - with a smooth metal surface using a trowel or rule, the solution slides down in about 7-8 seconds in one compact piece, rather than flowing down or sticking tightly to the tool.

In the finished plaster mixture, the “stickiness” of the plaster solution is artificially increased by adding small proportions of powdered water-soluble carbocellulose or polyacetate adhesive compositions. They displace air from the surface of the plaster mass and reduce the surface tension coefficient of bound water.

Thanks to this, the frozen layer acquires a very even and smooth surface. As an alternative to preparing walls and plaster mixtures, you can use ready-made liquid KMS compositions intended for priming walls and preparing plaster solutions.

But most often to improve the ductility of plaster cement-sand mortars based on M400 I, craftsmen and amateurs use cheap washing powder or liquid synthetic detergent, in a proportion of 50-70 grams per 50 liter tank of mixture. It is difficult to assess the effectiveness of this method due to conflicting reviews, but to be sure, it is better to test the recipe with a surfactant using small portions of the plaster composition.

A small amount of fatty clay, 50-100 grams per 15 liters of water, has a roughly similar, but less expressive effect. Clay mass rub by hand in water until a homogeneous cloudy suspension is obtained, which is filled with a dry mixture of cement and sand. The plaster mass becomes more plastic and less susceptible to high temperature air, takes longer to dry than usual. If you overdose the required proportion of clay or dry it in a strong draft, a network of microcracks may form on the plastered surface.

In the previous recipe, clay can be replaced with lime paste or a liquid lime substitute in the proportion of 150 grams of additive per 50 kg of plaster mixture. This version of plaster can be prepared for external walls and even semi-basements.

For walls whose surface is subject to regular and fairly strong temperature changes, it is better to use the addition of a small proportion of chopped fiber material based on polymers, fiberglass or fiber structures to the mixture.

Conclusion, special components for plaster

To reduce the density of the plaster and increase thermal insulation, the composition for plaster can be added to required proportions special types sand and ground natural raw materials. Flour and grains from crushed dolomite and calcined vermiculite increase the number of pores and microcavities in the volume of the cement mortar of the plaster up to 30-33%, and in special proportions, air entrainment in the plaster mass can reach 47-50%.

The number of pores can also be increased by using special reagents such as Ceresit CR166, specially designed to reduce the amount of water vapor in the atmosphere of enclosed spaces.

Making your own plaster mortar does not require extraordinary knowledge; it is enough to accurately maintain the proportions of cement and sand and use special additives in the mortar. Buying a ready-made plaster mixture will cost 2-2.5 times more expensive at an average level of plaster quality.