The online strip foundation calculator will be useful for both developers who install it themselves and professional builders. The service allows you to determine the area of the base of the foundation strip, which can subsequently be used to calculate waterproofing, as well as the volume of concrete, reinforcement, wire for tying it, and material for formwork.
The importance of accurately calculating the strip foundation will allow you to avoid cost overruns, which amount to a quarter of the cost on the scale of the entire construction. Compliance with the construction schedule can be disrupted by forced downtime when it turns out that due to a simple error in manual calculations there is not enough material.
How to use the service - some explanations
The calculation of a strip foundation for a house is based on the use of the following design parameters:
- location in terms of load-bearing walls of a new building - type of foundation;
- tape width;
- tape length;
- the height of the cross-section of the foundation, taking into account its underground part;
- section width.
These parameters are quite sufficient for calculating concrete. The cubic capacity of the base (its volume) calculated by the concrete calculator for a strip foundation will represent the consumption of concrete for the construction of the entire structure.
The selection of the components of a concrete mixture (water, cement, crushed stone, sand) depends on the brand of concrete, the mobility indicator of the mixture, the brand of cement, the fraction of fine and coarse aggregate, and the type of superplasticizer. By entering the weight of the finished concrete mixture in one bag into the field of the online calculator, you can obtain the concrete consumption for constructing a unit volume of a strip foundation.
To calculate the reinforcement for a strip foundation, you must fill in the following fields in the calculator:
- length, width and height of the foundation;
- number of horizontally located reinforcement threads (pcs.);
- pitch between vertical rods (m);
- connecting rods (pcs.);
- reinforcement diameter (mm).
The construction calculator for determining the material consumption for strip foundation formwork will perform all the calculations so that the temporary enclosing structure can withstand the enormous pressure of the concrete mixture. The initial data for the calculations are:
- board material. The decisive factor in ensuring the strength of the structure is the type of wood and the moisture content of the lumber;
- its thickness. A board of considerable thickness, which has a margin of bending strength, prevents deformation of the temporary structure or the appearance of a crack in it;
- foundation base perimeter;
- the height of the foundation or its depth. When determining this parameter, the load on the strip foundation from the side of the house is calculated. So, for a brick house, the height of the foundation should be greater than its value determined by the foundation calculator for a house made of foam blocks or sandwich panels with the same soil characteristics.
As a result, the calculator will display the volume of lumber required, the recommended number of supports and the spacing between them.
An important function of the service is to determine the cost of a strip foundation, determined taking into account the price per bag of cement, per ton of sand, crushed stone, reinforcement, per cubic meter of boards and their calculated quantity in the corresponding units of measurement.
An example of calculating materials for the construction of a strip foundation
The method for determining the required materials using an example will help you understand the algorithm for calculating their consumption using a calculator.
For example, the project provides for the construction of a house with plan dimensions of 9 x 7 meters. The internal walls are 22 meters long. As a result, the total length of the foundation will be:
2 (9 + 7) + 22 =54 meters.
The initial data for the calculation are:
- foundation width of 30 cm;
- foundation depth – 75 cm.
All parameters must be reduced to one unit of measurement.
- Calculation of concrete volume
- We determine the amount of concrete that needs to be laid at the base of the building:
- 54 x 0.3 x 0.75 = 11.55 cu. m.
- Component calculation
- The project provides for the use of concrete grade M250. To do this, we use a component ratio of 1: 4: 4 (cement, sand, crushed stone). The amount of water is calculated depending on the required plasticity of concrete and the size of the filler fractions.
- We find that for 1 m³ of concrete made from M400 cement and crushed stone with an average grain size of 20 mm, you need:
- cement 336 kg;
- crushed stone 1344 kg;
- sand 1344 kg;
- water 205 liters.
- For a total concrete volume of 11.55 m³, the amount of materials will be equal to:
- cement: 11.55 x 0.336 = 3.88 tons.
- crushed stone: 11.55 x 1.344 = 15.52 tons.
- sand: 11.55 x 1.344 = 15.52 tons.
- water: 11.55 x 0.205 = 2.36 tons or 2.36 thousand liters.
- Reinforcement calculation
- In our example, the reinforcing elements are located along the volume of the base in two horizontal rows and vertically - every 50 cm.
- We calculate the required amount of reinforcement for horizontal rows by doubling the perimeter of the tape: 54 x 2 = 108 meters.
- For vertical reinforcement bars 0.75 m long (foundation height) you will need 108 pieces: 54 x 2. The total length of the reinforcement is: 108 x 0.75 = 81 meters. Its diameter is included in the project after calculating the strength of the foundation.
- Calculation of lumber for formwork
- It is assumed to use a 25 mm board, 6 meters long, 0.2 m wide. The calculation is based on the sum of the areas of the lateral surfaces of the above-ground part of the foundation (its height is 0.30 m):
- 2 x 54 x 0.3 = 108 linear. m. x 0.3 m = 32.4 m²
- Considering that each board has an area of 1.2 m² (6 x 0.2), the number of boards for formwork will be determined: 32.4: 1.2 = 27 pieces. Taking into account the consumption of material for connecting the boards to each other and the stock, their number will increase by 50%, i.e. 27 x 1.5 ≈ 40 pcs. boards
- It is assumed to use a 25 mm board, 6 meters long, 0.2 m wide. The calculation is based on the sum of the areas of the lateral surfaces of the above-ground part of the foundation (its height is 0.30 m):
To accurately determine the time for completing concreting work and the amount of material consumed, calculations should be made; an online calculator for calculating the volume of concrete will help with this.
The concrete volume calculator will independently calculate for you the required amount of solution, providing the most accurate figures. Consumption is taken into account in cubic meters.
Calculate the volume of concrete for the foundation slab or screed
The calculator below produces calculation of concrete for slab foundation in accordance with building codes and regulations. To calculate a slab foundation, you need to know the area and thickness of the slab, because a slab is an ordinary rectangular parallelepiped.
A slab foundation is a closed reinforced concrete solid monolithic slab that is laid under the entire area of the house, thereby distributing the load along the entire length.
Enter your data in the fields for calculation:
Correctly calculating the cubic capacity of concrete in this case is much more difficult: we must multiply the length of the structure, which includes the perimeter from the outside and the length of all partitions between rooms, by its height and width (provided that the foundation strip has the same cross-section along its entire length).
It is imperative to take into account the depth of groundwater, landscape, soil and other factors when calculating the height of the foundation.
Construction technologies have been developing over many centuries.
One of the most important elements of any building is the foundation, which ensures the integrity and durability of the entire house.
The main and most successful version of the base design is a simple and reliable type of support system.
With the advent of high-quality and affordable concrete, the tape has gained capabilities that are far superior to the properties of alternative options, primarily in terms of load-bearing capacity and efficiency.
At the same time, the performance of the tape is almost completely determined by the quality of the material, its composition and properties.
Class and grade are two independent quantities indicating the quality of concrete.
Both of them reflect the degree of compressive strength of the material, but differ in specialization.
Grade (M) - an indicator related to the quantitative value of cement content. Class (B) - an indicator of the material’s resistance to external loads.
The grade of concrete demonstrates the cement content. This is a very unstable and uninformative indicator, the main value of which is the freezing time.
Two pieces of hardened concrete with different qualities can have the same grade, since the cement content does not completely determine the finishing quality of the material. There are brands from M50 to M500.
The most common of them is M200, which is used for, production of stairs and other structural elements.
Smaller grades are used to fill the preparatory layer of the strip foundation or auxiliary elements.
More durable grades - M300-M500 are used for casting special structures, dams, and critical reinforced concrete parts.
Unlike the grade, which shows the average strength value and allows significant fluctuations in quality, the concrete class indicates the ultimate strength, which is ensured in 95% of cases.
The class is a more accurate indicator, so most manufacturers switch to class when designating the quality of a material, although the use of the brand by inertia is also widespread.
Online calculator
Scheme for calculating cubic capacity for strip foundations
The volume of concrete is calculated based on the design parameters of the tape. In order to determine the required amount of material, it is necessary to calculate the volume of the tape.
The cross-sectional area is determined by multiplying the width by the height. Then the resulting value is multiplied by the total length of the strip foundation, taking into account the length of all sections, including lintels.
It is necessary to use the same units of measurement to avoid confusion in determining the digits.
If the length of the tape is in meters, then the cross-section must be calculated in square meters.
IMPORTANT!
Some sellers list their goods in tons, while others count their goods in cubic meters. The volume of concrete obtained in the calculation may need to be converted into weight units, for which it is necessary to know the specific gravity of the concrete of the desired grade. This table value is available in the SNiP appendices. The volume is multiplied by the specific gravity to obtain the total amount of material.
How to count
Let's consider a specific example of calculation. There is a tape with a total length of 30 m, a width of 40 cm and a height of 1 m.
Determining the cross section:
0.4 1 = 0.4 m2.
Tape volume:
0.4 30 = 12 m3.
Weight of concrete (grade M200):
2.432 12 = 29.184 tons.
NOTE!
All values must be increased by 10-15% in order to have some reserve just in case. Therefore, it is necessary to prepare the material at the rate of 32 tons (we increase 29.2 by about 10%).
What requirements must it meet?
Basic requirements for concrete used in the manufacture of critical load-bearing structures:
- Strength, resistance to all external loads.
- High load-bearing capacity.
- The combination of components should provide maximum compressive and torsional strength.
- High frost resistance.
- Resistance to moisture (for the most critical structures, special hydrophobic additives are used).
The numerical values of the required parameters are determined by the purpose of the tape, magnitude of loads and operating conditions.
Self-production requires experience, the use of equipment and several assistants, otherwise there is a risk of interrupting the pouring of the foundation, which is unacceptable.
In what proportions should it be mixed?
If for some reason it is not possible to order ready-made concrete, you have to prepare it yourself. To do this, you need to know what components are used in the manufacture of the material and in what quantities they are present in the mixture.
Common types of concrete consist of the following elements:
- Sand.
- Crushed stone.
- Cement.
- Water.
IMPORTANT!
Do not confuse concrete for pouring the foundation and mortar for laying bricks. These are different materials. No additives for elasticity (soap solutions or lime) should be added. The material should be as rigid as possible.
The most common proportion for making structural types of concrete:
- Cement - 1 part.
- Sand - 3 parts.
- Crushed stone - 5 parts.
- Water - 0.5 parts.
Depending on the specialization and characteristics of the foundation, these proportions may change in one direction or another.
The cement usually used for the production of heavy concrete belongs to the M400 or M500 grades. Smaller species are not suitable for such purposes.
The sand must be clean and free of foreign impurities. Used river, less often - washed gully, without foreign impurities.
Organic matter and clay inclusions are especially undesirable. They increase the creep and shrinkage of the material, so they need to be gotten rid of.
The crushed stone used in preparing the mixture must be of medium size (1-3 cm) and free of organic impurities.
The presence of aggregates (sand and crushed stone) in concrete is mandatory. Water and cement form the so-called. concrete stone, highly susceptible to shrinkage, reaching up to 2 mm per meter of height.
The presence of fillers reduces shrinkage and forms a kind of, receiving loads and redistributing them throughout the entire volume of the material.
When talking about the proportions of concrete, we should focus on the units of measurement. Usually parts are counted in weight units.
In practice, they most often use volumetric measures, for example, buckets.
It must be borne in mind that the weight of one bucket is different for each material:
- Sand - 19 kg.
- Cement - 15 kg.
- Crushed stone - 17.5 kg.
Taking into account the difference in volumetric weight, the optimal proportion of components (in buckets) will be the ratio 2-5-9 (C-P-SC).
Water is usually added to half the volume of cement. Knowledge of these subtleties will allow you to correctly mix the composition and avoid mistakes when creating such a critical structure as a strip foundation.
How to knead correctly
The best way to make concrete is to use a concrete mixer. It is not necessary to purchase it for your own use; you can rent the device for several days.
It is necessary to mix such an amount of material that can be used in 2 hours.
This rule allows material to be supplied rhythmically to the site without overloading workers..
It should be noted that the most important thing is to do the work as quickly as possible, so you should be guided by the requirements of the situation.
Concrete is mixed as follows::
- The required quantities of sand, cement and crushed stone are poured into a concrete mixer or a specially designated container.
- They are thoroughly mixed until a homogeneous mixture is obtained.
- Water is gradually poured in. Throughout the entire process, the material is constantly mixed.
- The result should be concrete that mixes fairly easily and does not roll off the shovel too freely.
If wet sand is used, the amount of water should be reduced slightly. In general, the consistency of the material is determined by your own feelings.
If necessary, add water, since the concrete is poured into it. Material that is too thick does not lay down evenly and forms bubbles that are difficult to get rid of.
Useful video
In this section you will find out how much concrete is needed for a strip foundation:
Conclusion
The quality of concrete directly depends on the properties of the components, proportions and manufacturing technology.
When making it yourself, it is possible to control the composition of the mixture, but when using ready-made concrete, larger quality tolerances should be taken into account and a heavier grade should be chosen.
This will not make a big difference in costs, but will help to obtain a high-quality and durable material for filling the tape.
In contact with
When building a house yourself, it is important to get a really solid foundation, and one of the options for calculating a strip foundation is an example of a building with a perimeter of 6 × 8 m made of aerated concrete with an attic 2nd floor without basement (basement) premises. This type of support is the most universal solution in most cases of individual construction of a permanent residential building. Careful calculations at the design stage will become one of the conditions for the long-term operation of the building.
Procedure for settlement operations
The sequence of calculating a monolithic strip foundation will consist of 2 main stages, which will determine the initial data for determining the dimensions of the structure. For each specific construction site you need:
- determine the operating loads;
- find out the bearing capacity of the underlying soil.
The ratio of the effective weight load of all elements of the building, including the foundation, to the bearing capacity of the soil base will allow you to find out the optimal value of the width of the strip support.
The area of the supporting sole is of decisive importance. The width of the tape itself can vary depending on the total dimensions of the load-bearing walls (block + insulation + cladding). shown in the drawings:
For a strip structure with a rectangular cross-section, the widths along the entire vertical are equal. The choice of a T-shape, in which the area of the foundation base is larger than the base, occurs in the case of constructing a massive building (2 or more floors) from expanded clay concrete blocks or bricks. For frame houses, timber buildings, log houses, a rectangular section will usually be sufficient.
Calculations of the area of the base of the supporting part for monolithic and prefabricated types of foundation are no different.
All requirements for determining the calculated values and accepted coefficients are set out in detail in the following regulatory documents:
- SNiP 2.02.01-83*. Foundations of buildings and structures. Gosstroy USSR, 1995
- SNiP 2.03.01-84*. Concrete and reinforced concrete structures. State Construction Committee of the USSR, 1989
- SNiP 23-01-99*. Construction climatology. Gosstroy of Russia, 2003
- SNiP 2.01.07-85. Loads and impacts. State Construction Committee of the USSR, 1986
The rationality of choosing a certain type of foundation structure directly depends on the engineering and geological conditions of a given site, the working conditions in the complex of all building elements in real conditions.
Design errors, violations of foundation laying technology, and savings on work and materials not justified by calculations can lead to the need to take additional measures, the cost of which will be several times higher than the initial costs of constructing the foundation.
Load collection
The design of the foundation begins after the parameters of the building installed on it are determined.
To do this you need to do the following operations:
- draw a house plan on a scale with markings for each wall;
- set the height of the basement elevation, assign the materials used for it;
- determine the types and thickness of materials used for thermal insulation, waterproofing, wind protection, finishing of horizontal and vertical surfaces indoors and outdoors.
Find the specific gravity of each component in the reference tables. An example of such a table:
In this example of foundation calculation, you need to select:
- walls of the 1st floor made of gas block 0.4 m thick, 3 m high, 28 m perimeter - 20,160 kg;
- attic walls 1.2 m high, thickness 0.25 m, same length, log - 5150 kg;
- frame partitions, 17 m long and 2.7 m high, 16 m – 1.2 m, weighing 19530 kg in total;
- plank flooring on wooden beams with an insulation density of 200 kg/m³ - 14400 kg (floors of the 1st and 2nd floors), with a coefficient of 1.2 = 17280 kg;
- gable roof made of ondulin with an area of 58 m² - 1740 kg, with coefficient. 1.1 = 1914 kg;
- payload is 200 kg/m², (safety factor 1.2) – 11520 kg.
In total, the weight of the main above-ground structures will be 75554 kg.
If a private house does not have a small base area at a significant height, then the influence of wind load on the foundation can be neglected.
It is better to take the snow load according to the maximum value for a given zone (100 kg/m²). With a safety factor of 1.4, the roof would weigh 8120 kg.
In total, the estimated weight of the house without foundation will be 83,674 kg
For small private buildings, the division of loads is usually neglected and simply summed up without using combination reduction factors in the calculation.
Foundation height
When assigning a design task, it is necessary to determine the dimensions of the strip base. To determine the load from the foundation, you need to set its depth.
Seasonal indicators are shown on the maps:
For a more detailed calculation, this value is taken from the table:
The regulatory requirement for the location of the bottom of the buried foundation is 0.2-0.3 m below the freezing mark in a given climatic zone.
- below the freezing depth for clay and loam the mark is taken equal to 0.5 GP; for other types of soil there is no dependence;
- above GP - not lower than GP (except for gravelly, rocky sands).
For light buildings (wooden, foam concrete, small brick) on slightly heaving soils, it will be 0.5 - 0.7 m. In the design calculations, a coefficient of 1.1 is used. Accordingly, for the house being built in the example, you should choose a depth of 0.6 m and a base height of 0.4 m.
Tape weight
You need to add the own weight of the support to the calculated load of the house. You can build from foundation blocks and take the values from the table:
When laying FBS 24.4.6 in 1 row to ground level, the weight without adding brick to the base will be 15,167 kg. A base made of solid brick 0.4 × 0.4 m will weigh 8064 kg. The total weight of such a foundation will be 23231 kg with a support area of 0.4 m × 28 m = 11.2 m². Now you should calculate a light self-leveling foundation with a widened base.
The height of the underground part of the monolithic concrete strip will be 0.6 m, the base 0.4 m, the thickness is equal to the wall made of blocks 0.4 m. Non-reinforced concrete has a volumetric weight of 2400 kg/m³, load safety factor = 1.1. Then the load will be: 1 m × 0.4 m × 2400 kg/m³ × 1.1 = 1056 kg/m.
The width of the foundation base should be taken as 0.6 m. If we subtract from it the previously taken into account tape size of 0.4 m, we can obtain a total protrusion of 0.2 m.
The weight of the reinforced concrete base at 0.3 m is 2500 kg/m³, in our case it will be 0.3 m × 0.6 m × 2500 kg/m³ × 1.1 = 495 kg/m.
Backfill soil with a density of 1650 kg/m³, coefficient 1.15. The result is 0.2m × 1650kg/m³ × 0.3m × 1.15 = 113.85 kg/m.
We add up the resulting load values 1664.85 kg/m or 46615.8 kg. The sole area for this option is 0.6 m × 28 m = 16.8 m²
We perform a similar calculation for a rectangular concrete monolith 0.3 m wide (with a recessed base): 1 m × 0.3 m × 2400 kg/m³ × 1.1 = 792 kg/m. The mass of the entire belt will be 22176 kg, the support area will be 8.4 m².
Base load-bearing capacity
To accurately calculate the bearing capacity of the soil lying on a site, its physical and mechanical characteristics obtained as a result of engineering and geological surveys will be required. The costs of ordering an IGE report in the future can pay off handsomely if the site is located in difficult unfavorable conditions.
In a simplified way, you can use reference tables that contain the given values of this indicator for typical types of soil, for example, the following table:
An important condition is the homogeneity of the underlying layer without the formation of so-called “lenses”. To clarify all the features, practical research into the geology of the site and desk calculations are needed based on the most accurate data.
Carrier Ratio
It is possible to create the selected foundation option if the total load from the building is less (in extreme cases, equal) to the bearing capacity of the soil. We consider the resulting strip base options:
- FBS 24.4.6 blocks with a brick base (83674 kg + 23231 kg)/11.2 m² = 9545 kg/m² or 1 kg/cm².
- Monolithic concrete with an expanded base (83674 kg + 46615.8 kg)/16.8 m² = 7754 kg/m² or 0.8 kg/cm².
- A strip monolith 0.3 m wide will have the following value: (83674 kg + 22176 kg)/8.4 m² = 12601 kg/m² or 1.3 kg/cm².
From the comparison it is clear that at minimal cost it is possible to build a building weighing 106 tons on a self-leveling strip foundation 0.3 m wide.
Expert advice on how to independently calculate the supporting area of foundations when building your own house is presented in this video:
Advanced builders can always use free calculation programs that can be downloaded (or worked online) on the Internet.
An example of such a program is shown in the photo:
However, there are doubts about the accuracy of calculations of complex cases on these calculators, since the operation of their formulas is not clearly controlled by the user (roundings used and completeness of the calculation).
A reliable result is obtained using the methods given in building codes and special reference literature. It is advisable to use calculator programs to more easily calculate the required amount of consumables.
An online calculator for a monolithic strip foundation will help you calculate the parameters necessary for construction. With its help, you can clarify the required dimensions of the foundation and formwork, find out the total volume of materials, make sure that the diameter of the reinforcement meets the standards and determine the consumption of concrete. To find out whether a strip foundation is suitable for your purposes, do not forget to consult with specialists.
The calculations take into account the parameters given in SNiP 3.03.01-87, SNiP 52-01-2003 “Concrete and reinforced concrete structures” and GOST R 52086-2003.
A strip foundation is a closed monolithic strip of reinforced concrete that runs under all the load-bearing walls of the building. This solution allows you to distribute the building load over the entire area of the belt. The main loads of such a foundation are concentrated at the corners of the contour. A strip foundation has a number of advantages over a solid foundation: material savings, better resistance to soil heaving forces. As a result, it successfully prevents subsidence or tilting of the structure built on it.
In the construction of private houses and other small structures, strip foundations are very popular. It is quite economical and allows you to achieve excellent performance characteristics.
There are several types of strip foundations. They are divided into prefabricated and monolithic, as well as deep-buried and shallow-buried. Which strip foundation to choose? This depends on the expected load, soil characteristics, available materials and other parameters, individual in each case. That is why we advise you to first consult with specialists.
Foundation design is one of the most critical design stages during the construction of a building. If the foundation is not strong enough, this will affect the stability of the entire building. And correcting foundation errors is extremely labor-intensive and expensive work.
When filling out the fields of the calculator, check the additional information displayed when you hover over the question icon.
At the bottom of the page you can leave feedback, ask a question to the developers, or suggest an idea to improve this calculator.
Explanation of calculation results
Total length of tape
It is also the perimeter of the foundation (without taking into account the thickness, measured in the middle)
Tape sole area
The total area where the bottom of the foundation rests on the ground. Requires waterproofing materials.
Outer side surface area
The total area of the lateral surface of the foundation, which determines the amount of insulation.
Concrete volume
The required amount of concrete for pouring the foundation with the selected parameters. It is indicated approximately, since compaction is possible during pouring, and delivery does not always guarantee the exact volume. We recommend ordering concrete with a ten percent reserve.
Concrete weight
Approximate weight of concrete at average density.
Soil load
The load exerted by the strip foundation on the support area.
Minimum diameter of longitudinal reinforcement bars
Calculated according to SNiP standards. The relative content of longitudinal reinforcement in the section of the foundation strip is taken into account.
Minimum number of rows of reinforcement
To counteract the natural deformation of the foundation under the influence of compression and tension forces, it is necessary to install longitudinal rods in different belts of the foundation (at the top and bottom of the belt).
Total weight of reinforcement
The weight of all the reinforcement bars combined.
Amount of reinforcement overlap
Use this value if you need to attach overlapping reinforcing bars.
Total length of reinforcement
The total length of all reinforcement cage bars, including overlap.
Minimum diameter of transverse reinforcement (clamps)
Determined based on SNiP standards.
Spacing of transverse reinforcement (clamps)
In order for the reinforcement frame to have rigidity and not be deformed, the correct spacing of the transverse reinforcement should be taken into account.
Total weight of clamps
The mass of clamps required to construct the entire foundation.
Minimum thickness of the formwork board (with supports every meter)
Required thickness of formwork boards for given foundation parameters and support spacing every meter. Calculated based on GOST R 52086-2003.
Number of formwork boards
The number of boards with a standard length of 6 meters that will be required for the construction of the entire formwork.
Formwork perimeter
The total length of the formwork, taking into account the internal partitions.
Volume and approximate weight of formwork boards
This volume of boards will be required for the construction of formwork. The weight of the boards is calculated from the average density and moisture content of coniferous wood.