Proportions for 1 cube of solution. How much sand and cement is needed to plaster walls?

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-by-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).

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 obtain lime mortar, cement must be added in a ratio of 1 to 3 in relation to the lime component. When using clay, the volume of cement per 1 cubic meter the solution changes, and you need to use a ratio 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 the foundation, the strength of the masonry is the determining factor. 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 interior 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 have 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, in a 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 cube of mortar, you can begin to prepare necessary equipment and materials. Filling should be carried out in the warm season. 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. It will be possible to increase the volume of the solution to 0.25 cubic meters if you use M300 cement. 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 get high-quality composition, which 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.

Before you start construction work, it is necessary to calculate the use of building materials. If the consumption of bricks, roofing and lumber is easy to determine, then calculating the exact amount of cement is much more difficult. And it is necessary to purchase exactly as much as will be consumed, because such properties of the material as the ability to absorb moisture from the air make its storage undesirable.

To carry out the calculation you need to know the following:

1m3 equals 1000 liters

Standard weight of a bag of cement is 50 kg

One bag of cement contains 36 liters

1 liter of cement is equal to 1.4 kg/l (50/36)

Calculation of cement per cubic meter of plaster solution

When conducting plastering works are used different kinds cement mortars with different properties. As a rule, the following proportion is used: one part cement to three parts sand, however, such features as density, viscosity and time for complete drying are also taken into account.

To calculate the amount of cement when processing a wall, it is necessary to take into account the parameters of the area and thickness of the layer. So, for a wall that does not require leveling, the area of ​​which is 50 m2, with a layer of plaster of 2 cm, the cement consumption per square meter will be equal to 0.02 m3 (0.02x1x1). Given the proportions of 1:3, 0.005 m3 of cement will be required. Therefore, for a wall of 50 m2, 0.025 m3 of cement will be required.

Another way

Solution 1 m3 sand + 1/3 m3 cement (333 l)

333l x 1.4kg/l=466kg – amount of cement for one cube of mortar

Calculation of cement per cube of mortar for floor screed

To fill a screed with a thickness of 5 cm and an area of ​​60 m2, the following calculations are made: 60x0.05 = 3 m3 (amount of cement mortar). Taking into account the proportion of 1:3, the result is 1 m3 of cement.

Another way

Solution 1 cubic meter of sand + 1/3 cubic meter of cement (333 l)

333l x 1.4kg/l=466kg – the amount of cement required for one cube of mortar

Calculation of cement per cube of foundation mortar

Based on the optimal proportion of cement, crushed stone and sand for foundation mortar, which is 1:5:3, and taking into account the size of the foundation, you can similarly calculate the cement consumption for its construction. To avoid errors in calculations, another 10% must be added to the total volume.

Calculation of cement per cube of masonry mortar

For the construction of walls, cement consumption is made taking into account the area of ​​the building and the type of masonry (block or brick). The optimal ratio of sand and cement for masonry is 1:4

Solution 1 m3 sand + 1/4 m3 cement (250 l)

250l x 1.4kg/l=350kg – the amount of cement required for one cube of mortar.

Buying only the required amount of cement, a material that is highly hygroscopic, means realizing reasonable savings.

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 optimal ratio filler and binder (4-5 parts of sand).

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 required quantity screeds are made according to the formula:

(Screed area, say 20 m2) * (screed height, and it is translated in meters, and 10 cm = 0.1 m) = volume of the 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-by-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).

At independent execution 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:

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 level deviation of the plane is 2-2.5 cm. The greater the surface unevenness, the more thick 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 of materials.

At the junction of two surfaces made of various materials, we mount 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

Determine the surface difference relative to 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 standard rate consumption 8.5 kg per sq. m:

Marble chips give the “Bark Beetle” mixture a relief

The composition for finishing plaster contains bark beetle marble chips, thanks to this it turns out 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 instruction:

1. We prepare the surface. We clean the wall from dust and flaking building materials. We remove rust and oil stains.
2. We prime the surface in 2-3 layers, applying each subsequent layer after the previous one has dried.
3. 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 with 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.
4. 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.
5. 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. For more information about plastering work without beacons, see 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:

1. 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.
2. 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. The surface treated with cement composition 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.

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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 quickly as possible, before the process of partial binding of free water with cement grain begins. You can buy ready-made plaster mixture for the most different options plaster, in which the optimal proportions of sand and cement have already been selected.

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:

1. The sand must be sifted and washed; it is extremely important to obtain large and medium sand fractions and eliminate dust and clay inclusions.
2. 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 a higher clay content or the presence of clay lumps in the mixture, a network of small cracks may form on the surface of the plaster.
3. 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 usually no more than 3 mm; it is excellent for finishing works surface finishing.

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 plastering or working conditions.

For large areas for plastering work, with a small amount of corrections or leveling of walls, Portland M400 of the first type is used; on the packaging marking after the letters PTs you can see the designation I or II. The first is cement with maximum speed set of 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 to reduce internal stresses 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, 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 the 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, ready-made plaster mixtures and wall preparations can be used. liquid formulations KMS 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. The effectiveness of this method is difficult to assess due to conflicting reviews, but to be sure, it is better to check the recipe with surfactants for small portions composition for plaster.

A small amount of fatty clay, 50-100 grams per 15 liters of water, has a roughly similar, but less expressive effect. The clay mass is rubbed 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 exposed 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 of 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.

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Not only the completion date of the work, but also, to a greater extent, the quality of the structure depends on the correct planning of the consumption rates of building materials. The most difficult thing in the calculations is exact compliance with technological standards. In addition, knowing the exact amount of materials, you can significantly reduce construction costs, since the amount of waste will be minimized.

Why bother with proportions?

If it is quite difficult to make a mistake in calculations applied to materials measured in linear units, then in the case of dry mixtures and their components, errors occur quite often. It will not be difficult to calculate the number of bricks for building a wall, knowing its dimensions, but to calculate the number of components for a cube of masonry mortar, difficulties may arise. In a word, we will consider the consumption of cement per 1 cubic meter of mortar for various purposes today.

To obtain high-quality cement mortar for certain purposes, it is necessary to strictly observe the proportions of not only cement, but also all other components. Crushed stone, sand, as well as cement, must also be added in a certain proportion. The fact is that if the consistency of sand or crushed stone is exceeded, the consequences for the structure as a whole can be very disappointing.

Consumption of cement and sand per cube of mortar

If you add too much crushed stone to the solution, then between the fractions there will be cavities in which the cement has not entered, and, accordingly, the product or structural element will not be monolithic and will not correspond to the design load and other characteristics. Hence the short service life, premature costs for repairs or even replacement of a failed element, if this is possible.

The same story can happen when the proportion of sand exceeds the norm. In this case, we involuntarily increase the consumption of cement per cubic meter of screed mortar, but we do not obtain the required strength in any case. This is where it comes from Golden Rule cement proportions:

You need to add exactly as much water as required technical specifications, no more, no less. The main factor influencing the quality and suitability of a concrete mixture for certain conditions is the brand and quantity of cement. In addition, we provide several different tables with approximate proportions for preparation concrete mixtures completely different purposes.

Golden proportion of concrete mixture

In principle, cement consumption rates fit into clear mathematical calculations, but in order not to overload builders with rough mental work, these tables were created. Each of them corresponds to the principles of proportional compliance that we cited above - 1/3/5. Accordingly, to obtain a hypothetical unit of the finished solution, it is necessary to mix nine equal parts all components.

In order not to go deep into the arithmetic course for the third grade secondary school, let's say that to obtain an average cubic meter of solution you need to have 333 kg of average cement. The entire difference in proportions is dictated by the characteristics of one or another technological process, in which the mixture is used - per cube of plaster solution and the same amount of mixture for strong screed Naturally, the amount of cement will be slightly different, as indicated in the tables.

The meaning of cement grade

It is also necessary to take into account the brand of cement. There is no need to recalculate the proportions each time if the purpose of the cement mortar or the brand of cement has changed. Each of the solutions is marked according to the brand of cement. So, if concrete grade 300 is needed for the construction of the foundation, and only M400 grade cement is available, it is enough to check the tables, which will give the necessary correction for the consumption of cement of the grade that is intended to be used.

For example, to get a cube of grade 100 concrete, you need to spend:

• 390 kg of cement grade 300;
• 300 kg m400;
• approximately 250 kg of grade 500 cement.

Features of preparing masonry mortar

But that’s not so bad. To prepare concrete, for example, for screeds or pouring a foundation, you do not need to take into account the properties of materials that are in direct contact with the solution. Masonry mixtures are much more complex in preparation and calculations, and all because each of wall materials has its own characteristics.

As a rule, adjustments are made to the consumption rates of materials for masonry mortar based on the structure, porosity, ability to absorb moisture, one or another building material. Of course, that golden ratio for brickwork will be correct, but an experienced mason will always make changes in proportions only by looking at the quality of the brick or wall block.

Thus, the calculation of the amount of materials for preparing the solution is based on practice-tested data compiled in tables, but taking into account amendments that provide for the characteristics of a particular material. Happy kneading!