How to calculate the volume of the foundation. Calculation of the volume of concrete for various types of foundations Calculation of the amount of concrete mixture
Liquid concrete is an aqueous solution of viscous consistency from components taken in certain proportions. After curing, it becomes a strong, reliable material, resistant to mechanical stress and natural phenomena.
Dry cement Source tk-stroyresurs.ru
Experienced builders advise making your own concrete mixture rather than buying ready-made ones. To prepare or determine material costs, you need to know exactly how much cement is needed per 1 cubic meter of concrete for the foundation. The calculation of components is carried out using a special system, and a number of factors must be taken into account.
Brand of concrete for the foundation
First of all, it is necessary to determine what brand of concrete is suitable for constructing a foundation for a particular house on a given soil. The foundation must have sufficient strength, rigidity and mobility after the mixture has cured.
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It is advisable to fill the foundation of a house with concrete that has all the necessary properties:
- M100 or M200 are absolutely not suitable for this purpose. However, some summer residents strengthen lightweight structures using M200. Experts do not recommend taking risks; such a building structure will not be reliable.
- Brands M300, M350 are suitable for foundation construction in all respects. M300 is most suitable in terms of technical characteristics for private construction. M300 allows you to obtain a solution of good quality and is offered at reasonable prices.
- M400 is used for foundations in the construction of industrial buildings and special-purpose facilities.
A house built on a solid foundation will last for many years without destruction of supporting structures or cracks in the walls.
How to find out the amount of cement
Concrete is a building material that contains sand, gravel or crushed stone, cement and water.
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There is a special regulatory document, on the basis of which professional estimators calculate the materials needed to prepare a high-quality mixture. However, in the private construction of low-rise buildings, simplified formulas are used.
The quantitative content of cement in the solution determines the properties and grade of concrete. Even a small deviation from the optimal value affects the quality of the solution.
Arithmetic method
Individuals use a simplified system that allows them to find out how much cement is needed per cubic meter of concrete for a foundation; the calculator greatly simplifies the process. For this purpose, perform the following actions:
- cement, sand and crushed stone are taken for concrete in the ratio 1:3:5, 1+3+5= 9 – 1 m3 of mixture consists of 9 equal parts;
- 1m 3 = 1000000 cm 3;
- 1000000 cm 3 / 9 parts = 111111 cm 3 – the volume of cement required to produce 1 m 3 of concrete;
- specific gravity of cement 3 g/cm 3 ;
- we convert the volume into mass: we multiply the volume with the specific gravity, the mass is 333333 g = 333.333 kg.
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On our website you can find contacts of construction companies that offer house design services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.
In this way we find out how much cement is needed per 1 m3 of concrete, taking into account the error - 333 kg of cement is required. A bag of cement, in standard packaging, weighs 50 kg. Therefore, the number of bags of cement per 1 cubic meter of concrete required is 6.66 or approximately 6.5 pieces.
How accurate is arithmetic?
This scheme makes it possible to almost accurately determine the content of M100 grade material. For other brands, this calculation system is conditionally correct, and the resulting number is only an approximate value. It is recommended to determine the mass of cement with an accuracy of up to 1 kg, crushed stone – up to 5 kg.
When mixing the mixture, you need to know that a 10-liter bucket holds:
- 15-17 kg of cement or crushed stone;
- 14-15 kg of sand.
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It is known that the higher the grade of concrete (density and strength) that needs to be obtained, the fewer bags of cement will be required.
Approximate tabular data
The approximate consumption of cement per cube of concrete for the foundation, depending on the brand used, is presented in the tables:
- mixture prepared on the basis of M300
| Concrete grade | M250 | M300 |
| 340 | 300 |
- based on M400
| Concrete grade | M300 | M400 |
| Required mass of cement, kg | 350 | 300 |
When the amount of cement of a particular brand in the composition changes, the brand of concrete changes. The values indicated in the table depend on the quality of the soil and the size of the crushed stone material, and therefore may change up or down during calculations.
Does it make sense to use M500 for the foundation?
Using the arithmetic method or tables, it is not difficult to find out, for example, how much M 500 cement is needed per 1 cubic meter of concrete for the foundation. At least 8 bags or 400 kg to obtain M400 mortar, used for the construction of foundations in professional construction.
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It is not advisable for 1 cubic meter of concrete to contain more than 350 kg of cement. An oversaturated foundation will be subject to severe cracking after the final evaporation of moisture. Therefore, it is not advisable to use the M500 grade for placing concrete under the foundation. This material is intended for other purposes.
Online foundation calculator
To find out the approximate cost of a strip foundation, use the following calculator:
Features of the right choice
Cement is crushed mineral powder. In a concrete mixture, it is the only binding component that holds sand, crushed stone or gravel together.
The grade of material is chosen taking into account the concreting technology. An error leads to excessive consumption of concrete and violation of proportions for other components. A foundation that has the wrong composition will not last long, and after a while the work will have to be repeated.
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The following parameters are important when choosing cement:
- compressive strength (strength is determined by this parameter);
- presence of impurities;
- grinding quality.
The choice of material is also influenced by the curing speed, hydrophobic properties, resistance to low temperatures, and operational requirements.
Previously, the marking M100-M500 was used, the number showed the strength in kg/cm 2. Since 2003, the rules have changed. For private construction, cement with strength class B32.5 (M300) is popular. It is offered at affordable prices, has the technical characteristics necessary for the foundation, and can withstand pressure of 300 kg/cm 3 .
Video description
More information about old and new markings is described in this video:
Types of cement
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Depending on the proportions of the incoming components, this material is divided into several types:
- Portland;
- slag Portland;
- pozzolanic;
- fast-hardening.
How much water do you need
When calculating the amount of materials per 1 cubic meter of concrete, it is dangerous to make a mistake when calculating the water for the foundation mortar. Violation of proportions leads to too thick or thin mortar, which is not suitable for strengthening the building.
According to the methods for calculating the water-cement ratio, a ratio of 1:2 is used. For one serving of dry mixture, take half a serving of water. The amount of water affects the consistency and brand of the solution. The more water, the less viscosity of concrete.
For example, using M400 cement, you can prepare concrete of any grade by pouring water in different quantities:
By multiplying the weight of cement (in kg) by the corresponding number in the table, you will find out the amount of water in liters. The table is valid if medium-sized crushed stone is used.
Features of guiding the solution
When building small private houses, the concrete mixture is often prepared independently. The procedure involves the gradual introduction of water into the dry composition, followed by thorough and constant mixing of the solution to prevent hardening. For this purpose, it is recommended to use a concrete mixer. Filling work should be carried out in a short time, until the induced solution has lost the required viscosity.
Component quality requirements:
- Cement fractions from 5 to 20 mm are separated by sifting through a sieve. Dry, loose cement is suitable.
- Sand should not contain unnecessary impurities. After sifting, sand with fractions from 1.5 to 5 mm is isolated.
- Gravel or crushed stone is medium in size, ranging from 8-35 mm.
- Water should not contain an increased amount of unnecessary chemical elements or be heavily polluted.
In a humid environment, cement quickly becomes damp and lumps form. Considering this, purchase it immediately before use. If you have no experience, you should choose medium or large crushed stone. Large stones provide a denser concrete structure and prevent the formation of air bubbles.
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High-quality pouring of the foundation requires removal of air bubbles or cavities from the concrete mass, which always appear during the pouring process. For this purpose, the concrete mass is compacted using specialized vibration installations for construction.
The clear answer is: is there one?
It is impossible to answer exactly how much cement is needed per 1 cubic meter of concrete for the foundation, or exactly how much concrete will be produced from a bag of cement. It all depends on what kind of concrete should be used for pouring the foundation for a particular house. The choice is influenced by:
- the dimensions of the future house and the building materials used, which determine its weight;
- soil characteristics: groundwater level, freezing depth.
The table below shows the content of the components necessary for laying the most popular brand of concrete - M300 - depending on the degree of mobility of the mixture:
In order to save money, it is recommended to purchase cement of a higher grade than the concrete required. The grade of concrete is always lower than that of cement.
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Conclusion
At first glance, preparing concrete for the foundation is not difficult. However, this is the most critical part of the work when constructing a residential building; errors when pouring the foundation will affect further work and during operation. Although a foundation cement calculator will help you calculate the amount of concrete, these will be inaccurate numbers, and the proportions may be significantly wrong, especially if you have never seen building materials before. In many cases, it is advisable to turn to professional craftsmen.
Or any other outbuilding, the reliability of the foundation is always given top priority. This is not surprising - the integrity of the entire building, its durability and, to a large extent, the safety of living or staying in it depend on the stability of the foundation. Many owners undertake the construction of foundations on their own, relying on recommendations for carrying out calculations and carrying out all stages of work.
It has become much easier for modern developers - in many cases they have the opportunity to order ready-made concrete mortar of the desired grade for pouring a foundation strip or slab. But it also happens that such a service is not available in the construction area, or, according to preliminary estimates, it is more profitable for the site owner to prepare the solution himself, right at the construction site. And for this you need to know what specific concrete composition is needed for the foundation and the proportions of the ingredients needed for mixing.
Below you will find calculators for quick and accurate calculations, and a brief explanation of the principle of their operation.
Prices for crushed stone
Calculators for calculating the weight and volume of concrete ingredients for pouring a foundation
CONCRETE M200 (strength class B15)
It may seem that concrete of this strength class will be rather weak for a foundation. But it is not so. It is quite suitable for the foundation of outbuildings, for the foundations of light frame structures, for one-story houses made of logs or timber. It is also widely used when pouring screeds or monolithic slabs under a garage, for arranging blind areas, paths, and platforms.
The foundation is the underground part of a building or structure that receives loads and transfers them to the ground. The most popular type of foundation for building houses is considered to be a strip foundation. This widespread use of strip foundations is explained by its versatility and affordable cost. Before you begin construction, you need to make a choice between a shallow and buried strip foundation.
Shallow strip foundation
A shallow foundation saves both budget and time. And labor costs will be significantly less, since its construction does not require a deep pit. The following foundation is used for lightweight structures of small area:
- wooden houses
- aerated concrete structures or buildings constructed from aerated concrete and foam concrete blocks, the height of which does not exceed 2 floors
- monolithic buildings with permanent formwork
- small structures built of stone
The depth of the shallow foundation reaches half a meter.
Recessed strip foundation
This foundation is used for the construction of structures with heavy walls, concrete floors, a basement or an underground garage. The length of the foundation depth must be calculated in advance. First, you need to determine the level of soil freezing, then subtract 30 cm and lay the foundation at this depth.
Preparing for work
To build a strip foundation yourself, you must first carry out precise planning. The need for careful calculations is explained by the fact that the foundation is one of the most important structural elements of any building or home. Mistakes made at the beginning of construction can provoke negative consequences during the operation of the house.
Marking
Marking is carried out by marking on the ground both the external and internal boundaries of the future foundation. To do this, it is best to use pegs or reinforcement rods and ropes. But it will be more effective to use special devices, such as laser levels. Remember that large errors in markings will noticeably affect the appearance of the finished building.
To achieve ideal results you need:
- determine the axis of the structure being built
- use a plumb line to mark an angle, then pull a rope from it at an angle of 90 degrees to two more corners of the structure
- use a square to determine another angle
- check the angles, focusing on the diagonals. If the test gives positive results, pull a rope between them
- take on the internal markings, retreating from the external markings to the distance of the thickness of the future foundation
When you are finished with the markings, study the differences in the surface at the construction site and select the lowest point to measure the depth of the trench and eliminate the difference in the height of the foundation. If the building is planned to be small, then the depth of the pit can be 40 cm.
Cushion installation and waterproofing of strip foundation
A sand cushion with added gravel should be laid on the finished trench. The recommended height of each layer is 120-150 mm. After this, each layer must be shed with water and compacted to increase density. To insulate the finished pillow, you need to lay out a durable waterproofing film on it.
Installation of strip foundation formwork
The formwork is usually made of planed boards approximately 40-50 mm thick. You can use slate for this purpose.
When erecting formwork, control verticality. The recommended height of the frame above the ground is 30 cm. This is necessary to build a small base. Asbestos concrete pipes are laid in the formwork to introduce sewerage and water supply into the building.
Place a plastic film between the concrete and the formwork; this will protect the formwork from contamination.
Laying reinforcement
The next stage is the installation of fittings. Reinforcing bars with a cross-section of 10-12 mm are connected with a special knitting wire so that the sides of the square cells are 30-40 cm. The reinforcement can be either steel or fiberglass.
Ventilation and communications
Pouring a strip foundation with concrete
Fill the formwork with concrete gradually. The thickness of the layers is 15-20 cm; to avoid voids and increase overall strength, compact the layers with a special tool - a wooden tamper or an internal vibrator.
You can order ready-mixed concrete from a factory or make it yourself using a concrete mixer. The recommended proportion of cement, sand and crushed stone is: 1:3:5.
The layers should not differ in composition. In cold weather, you should use a concrete heater and frost-resistant additives; in hot weather, water the concrete.
Completion of work
Once the concrete is poured, it should be covered with film to prevent drying out and left to gain strength for at least 2 weeks.
To calculate the amount of concrete for constructing a floor using a concrete screed, break the entire structure into parts. This will significantly increase the speed of calculations. The thickness of the screed can be from 40 to 100 mm - it depends on the brand of concrete. A thinner screed may crack prematurely, while a thicker one will take a long time to dry.
Calculating the volume of concrete for pouring a floor must be approached with all responsibility. Due to a lack of material, the quality of the constructed structure may suffer. If the screed is laid on a flat, horizontal surface, then the formula is used to calculate the volume of concrete: V = S x H, where S is the surface area of the screed, and H is its thickness. For example, with a room area of 20 m² and a screed thickness of 0.07 m, the volume of the mixture will be 1.4 m³.
The volume of concrete can be determined in another way. To do this, measure the thickness of the future screed and the floor area, then multiply the resulting values. Multiply the result by the consumption coefficient of 1.02.
To determine the volume of concrete to be poured in kilograms, multiply the resulting amount of concrete by 490. This way you will find out how many kilograms of cement will be needed to install the floor. Multiply the resulting amount of cement by three and get the required volume of sand. According to building rules, 490 kg of cement is taken per cubic meter of concrete mortar.
Before starting to create the foundation, the builder will have to determine the volume of concrete mixture required for pouring. If you correctly calculate the cubic capacity of concrete, this will allow you to avoid unnecessary expenditure of finances, prevent an unpleasant situation when work has to be stopped due to a lack of materials, and will also protect you from attempts at fraud when hiring a crew.
General calculation rules
As initial data you can use:
- foundation configuration;
- its parameters: length, width, thickness, depth.
A concrete structure necessarily contains reinforcement, which also occupies a certain volume. But since it is insignificant (less than 1% of the entire foundation), this variable is usually neglected.
The resulting volume value must be increased by approximately 10%, since losses of concrete are inevitable during its transportation, preparation and pouring. In addition, the mixture thickens and decreases in volume when bayoneted as air is removed from it.
You should be careful when making calculations: as a rule, if you need to urgently order an additional portion of concrete, the costs of its preparation and delivery increase significantly.
Slab base
A slab foundation is one of the types of shallow foundations that is used in low-rise construction in the case of complex soils, for example, heaving or unevenly settling. It is a monolithic rectangular or square slab with a thickness of 0.3 to 0.5 m.
- width;
- length;
- height.
If the foundation design includes stiffening ribs, the volume of each rib is calculated separately. The obtained values are summed up and added to the volume of the slab.
The strip base is a closed reinforced concrete structure, immersed in the ground to a certain depth and passing under the load-bearing walls of the future structure. Today this is the most popular, but also the most difficult type of foundation to calculate.
When calculating it, the following quantities are used:
Calculations can be done in different ways. For example, the volume of a structure where the foundation passes under the external walls and under the interior partition located in the middle can be calculated in three ways.
The first method consists of the following steps:
- The area of the figure formed by the outer walls of the foundation is calculated by multiplying the values of L and W.
- The volumes of voids formed by internal structural elements are calculated. To do this, you need to find the product of the parameters d and w and double the resulting value.
- Subtract the second number from the first number and multiply the result by the foundation depth.
The second method is used when constructing foundations of complex configurations or in cases where their different elements have unequal depths. The idea of the method is to break a complex figure into simple components, calculate the volume of each of them and find their sum. The foundation is conventionally divided into rectangular elements, which, for convenience, can be designated in different colors in the drawing.
The essence of the third method is:
- Find the surface area of the outer foundation walls by first determining their total length. In the example given, it will be: 2W + 2D - 4 T. The resulting value is multiplied by the thickness of T.
- The surface area of the internal walls is determined as the product of the values w, etc.
- The obtained values are summed up and multiplied by the depth of the foundation.
In addition to the rectangular foundation discussed above, there are other types of strip structures. If there is an expansion in the lower part of the base, which may have the shape of a rectangle or trapezoid in cross-section, its volume must be separately calculated and added to the volume of the rectangular part.
Sometimes the bottom of a strip foundation is made wider than its upper part, that is, the cross-section of the side has the shape of an isosceles trapezoid with a height equal to the depth of the foundation. In this case, the order of volume calculations changes slightly.
In accordance with the laws of geometry, the area of an isosceles trapezoid is equal to the area of a rectangle with sides equal to the height of the trapezoid and its midline.
Area of the trapezoid: S = Lh, where L is the midline of the trapezoid, calculated as the sum of the lengths of segments AB (top line points) and CD (base line points of the trapezoid), divided by 2, h - foundation depth.
Area of the rectangle: S1 = Lh (product of the lengths of the sides), that is, S1 = S2.
This means that the volume with a side section in the form of a trapezoid ABCD will be equal to the volume of the foundation with a side section in the form of a rectangle A1 B1 C1 D1, where A1 B1 = C1 D1 = L, A1 C1 = B1 D1 = h.
Columnar and combined base
Columnar foundations are free-standing reinforced concrete columns of round or square cross-section. To calculate the volume of concrete for such a base, you need to:
The same method is used to determine the volume of concrete for a pile foundation, which is used in the construction of light structures on heaving soils or when the load-bearing layer is deep. If the pile foundation is reinforced with a grillage - a parallelepiped-shaped structure, then the volume required for it is additionally calculated, as is done for a strip foundation.
In the case of a combined foundation, the structure contains elements of a columnar and strip foundation. The calculations determine:
- volume of concrete for pouring columnar elements;
- volume of concrete for pouring strip elements;
- the obtained values are summed up.
No matter how you calculate the volume of concrete, do not forget to add to the result a value that is 10% of the obtained value and round up to whole numbers.
Online calculator help
If you don’t want to spend hours doing calculations, you can use an online calculator found on the Internet, which will not only perform all the calculations, but also provide additional data on the amount of material for formwork and reinforcement, and the required volumes of concrete mixture components.
To perform the calculation, you will need to provide the following data to the program:
- Foundation type: tiled, strip, columnar, combined.
- Design parameters: length, width, thickness of internal and external elements, depth.
- Proposed brand of concrete. This data will be required to determine the number of components of the mixture.
After entering the data, the calculator will take only a few seconds to perform all calculations as accurately as possible, saving time and nerves. In addition, the likelihood of error in this case is minimal, provided that the initial values were entered correctly.
The disadvantage of the online calculator is that the choice of possible foundation configurations is limited, so it is not applicable for complex structures. But if you break it down into simpler elements, the calculations can be done automatically.
Number of components for the mixture
It is not always profitable to buy ready-made concrete, since it has a short shelf life. In most cases, home builders prefer to purchase dry ingredients and make the concrete mixture themselves. When purchasing, you must use weight units, not volume measures.
Consequently, the builder, who has finally calculated the required volume of concrete, now faces a new task - to determine how much building materials will be needed to create it, namely:
Independent calculation of the amount of ingredients is quite complicated, since it is necessary to take into account many factors, in particular: the brand of cement used, the fraction of crushed stone and the shape of its grains, the type of sand, its purity and humidity, and also do not forget that when adding water, the volume of dry ingredients decreases by approximately a third due to compaction.
On average, the weight of a cubic meter of heavy concrete varies from 1800 to 2500 kg, depending on the above factors.
The weight of its individual components is as follows:
- crushed stone - from 1150 to 1300 kg;
- sand - from 600 to 750 kg;
- cement - from 250 to 450 kg;
- water - from 150 to 200 kg (liters).
To obtain exact values, you can use an online calculator or tables where the abbreviation VTs is usually used. This water-cement ratio is the ratio of the mass of water to the mass of cement. VC is one of the most important characteristics of concrete, determining its strength. You can also find tables indicating the ratio of mixture components.
When entering initial data into an online calculator or selecting the desired line in a table, you should consider the following:
The grain size of crushed stone or gravel is selected so that it does not exceed 1/5 of the minimum design parameter (for flat slabs - 1/3) and half the distance between the reinforcement bars. Crushed stone differs from gravel primarily in its acute-angled grain shape and rough surface, which ensures stronger adhesion to other elements of the mixture than when using rounded and smooth gravel grains.
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