Construction begins with a project. It is recommended to first sketch even small structures on paper so that you can clearly see the proportions and estimate the consumption of materials. For serious buildings, you need design and estimate documentation made by professionals, but when building a private house, cottage, fence or garage, you can get by with online calculators or ready-made solutions. The most important issue in the construction of structures is the construction of a reliable foundation, and therefore the question of how to calculate the amount of concrete for the foundation is paramount.
It is not difficult to calculate concrete for the foundation if you are certain about the size and type of structure. The type of foundation and its dimensions should be determined by an experienced builder, based on the characteristics of the building under construction, the type of soil and the depth of its freezing in the area.
Tape
The most popular foundation for the construction of a private house is considered to be a strip foundation. It is a kind of closed ribbon of concrete running under all the load-bearing walls of the building.
How to calculate how many cubes of concrete are needed for the foundation? Calculators that help determine the consumption of cement-sand mortar for pouring are available on many construction-related websites, one of which is presented at the end of this material. To calculate the volume in cubic meters, you need to know the linear dimensions of the structure: height, width and total length of the base.
Concreting of the strip base occurs by pouring the finished cement-sand mixture into wooden formwork with pre-installed reinforcing mesh. Large fractions (gravel, crushed stone) are added to the solution to obtain higher strength characteristics of the foundation.
The dimensions of the base depend on the dimensions of the building that is planned to be erected. Typically, the width of the foundation strip is at least 300 mm, the height of the ground part is from 400 mm, and the depth can reach 1500-2500 mm, depending on the availability of groundwater, freezing depth and the desire to equip a basement. It is not recommended to install strip foundations on heaving soils if the formwork is buried below the freezing depth.
For the middle zone, when constructing small private houses and baths, it is enough to deepen them within 1500 mm with a height of the ground part of up to 400 mm.
The length of the foundation will be equal to the total length of all external walls, including the internal load-bearing wall, under which the foundation is also installed. As a result, having received all the required values, you can calculate the volume of concrete for the foundation. In this case, a calculator may not be required - just multiply all the indicators in meters and get the desired number in cubic meters.
The calculation formula looks like this:
V=h*b*l, Where:
- V – volume of solution in m3;
- h – height in m;
- b – width in m;
- l – tape length in m.
For example, for a building measuring 6x6 m and one internal load-bearing wall, with a foundation height of 2 m and a width of 0.4 m, the volume of mortar for pouring will be: V=2*0.4*30=24 m 3. With the same width and height of the foundation, for a house measuring 10x10 and two load-bearing internal walls, the calculation will look like this: V=2*0.4*60=48 m 3.
This calculation allows you to calculate the almost exact cubic capacity of the solution, but it should be remembered that during transportation some of the concrete is lost, and also if the formwork is loose, part of the concrete solution may leak out, but at the same time there is an additional internal volume occupied by the reinforcement frame. Therefore, it would be correct to introduce a correction factor in the direction of increasing the calculated value by 2%.
As a result, we obtain a more accurate formula for calculating the volume of concrete for a strip foundation:
V=h*b*l + 0.02*(h*b*l)
The resulting value is rounded to the nearest whole number. For our examples, the refined calculation will look like this: for a 6x6 house V=24+0.02*24=24.48 (25) m 3, for house 10x10 V=48+0.02*48=48.96 (49) m 3.
Slab
A slab foundation is a continuous monolithic foundation under a building site. For its construction, concrete of a grade not lower than M100 is used. Calculating the volume of this monolith is quite simple - just multiply the length, width and height of the slab.
Pouring a solution of cement and sand with the addition of large fractions for a monolithic slab is carried out to a height of at least 100 mm. Thus, for a slab with a thickness of 100 mm, the following volumes of concrete are obtained:
- for a house 10x8 – 8 m3;
- for a 9x9 house – 8.1 m3;
- for a house 18x8 - 14.4 m3.
This calculation is suitable for completely flat slabs, but to give the base higher strength characteristics, additional stiffeners are often installed in the form of trapezoidal longitudinal beams. Therefore, the correct calculation of a slab foundation must also include the volume of pouring stiffeners.
To the already obtained volume of the slab, it is necessary to add the volume of the stiffeners, for which the formula for the area of a trapezoid is used. The volume of a slab foundation with stiffeners is found as follows:
- Calculate the volume of your slab: V=h*b*l.
- Find the area of the trapezoid: S=h1*(a+c)/2, where h1 is the height of the edge of the trapezoid, and and c are the lengths of the bases of the trapezoid.
- Find the volume of the stiffener and multiply by the number of ribs: V1=S*l*n, where n is the number of stiffeners.
- The resulting volumes are added up and the total volume of concrete required is obtained: Vtotal=V+V1.
Typically, reinforcement is located at the bottom of the base in increments of 3000 mm. They can be made as exclusively longitudinal reinforcements, or with intersections, forming squares. Typically, the ratio of the wide part of the trapezoid of the stiffener is 1.5:1. To calculate a slab foundation, volume adjustments are also provided with an error factor of 2%.
Columnar
This type of foundation is a kind of pile field, only the support pillars are not driven in with a pile driver, but are poured into prepared pits. A columnar foundation allows you to get a reliable foundation with minimal material consumption. The pillars can have a round or square cross-section; they are placed along the perimeter of the building site and at the junctions of the walls.
The depth of a columnar foundation usually exceeds the freezing depth for a given area, and the above-ground part has a height of 400-500 mm. The building structure can be installed directly on the support pillars, but most often a grillage is installed around the perimeter, which connects the pillars into a single whole.
To calculate the volume of concrete required for pouring a columnar foundation, you need to know the length of the column, its cross-sectional area and the number of columns. If a grillage is provided, its linear dimensions will be required; the volume of the grillage is calculated in the same way as in the case of a strip foundation.
V=a*b*l*n, where a and b are the cross-sectional sides of the pillar, l is the length of the pillar, n is the number of pillars in the foundation.
To calculate the volume of concrete for pouring pillars with a circular cross-section, you will need a formula for finding the area of a circle: S=3.14*R*R, where R is the radius. We get the formula for calculating the volume of pillars with a circular cross-section:
To obtain the total volume of concrete required for pouring the pillars and grillage, it is necessary to add up the already obtained indicators, not forgetting the error factor of 2%.
Calculation of cement for the foundation.
Online foundation calculation calculator the site allows you to engage in full-fledged foundation design, facilitates calculations and helps save on materials, without neglecting building codes. The calculation method is based on an advanced mathematical model algorithm taking into account regulatory documents SNiP 2.02.01-83 (SP 22.13330.2011), SNiP 3.03.01-87 (SP 70.13330.2011), SNiP 52-01-2003 (SP 63.13330.2010) , SNiP 23-01-99 (SP 131.13330.2012).
Based on the results of the calculator, you will receive a detailed estimate for the construction of a turnkey foundation, a convenient and visual design drawing, a simple and understandable reinforcement tying diagram, as well as an interactive 3D model for assessing the resulting structure. We provide access to download all materials in OBJ, PNG and PDF formats.
You will be aware of the following parameters:
- Foundation characteristics. Width, thickness, volume, depth, permissible loads on the ground.
- Materials. Amount of reinforcement, tie wire, formwork boards, concrete, cement, crushed stone, sand.
- Volume of earthworks. The required cubic capacity of soil that will have to be cleared for the foundation.
At the moment, calculations of strip foundations (full) and monolithic slabs (simplified) are available. Calculators for calculating pile, column and screw foundations should appear soon. Bookmark our site and don't miss their appearance!
The site foundation calculator will demonstrate your future structure based on the built-in calculation of materials and reinforcement. Using 3D visualization you can see what your reinforced frame should look like, down to the smallest details.
Foundation calculation
The construction of any house begins with the calculation of the foundation; it is the support for the entire overlying structure, and the durability of the entire structure depends on how well it is installed. When deciding to carry out the work of creating a foundation with your own hands, it is important to avoid mistakes in the initial calculations, and even more so, there is no need to try to save on materials. Remember that a well-designed foundation is the key to your safety.
Instructions
The average user does not have to be a construction specialist to use our service. The interface is intuitive, and the program will indicate any invalid value with red highlighting.
In most cases, you only need to enter a minimum amount of information:
- estimated dimensions of the foundation;
- brand of fittings to choose from;
- brand of concrete.
In the process of calculating the foundation for a house, you may need to enter some additional values, but they can also be calculated on our calculators:
- block calculator (load calculation).
We have prepared an introductory video for you, which explains step by step all the functionality and operating principle of the online foundation calculator.
Our calculator also allows you to make calculation of the volume (cubic capacity) of the foundation in m 3, so that they know in advance how much excavation work needs to be done.
Concrete is the most important component of the foundation; in fact, it is its “flesh” and most of the characteristics of the foundation depend on how high-quality the mixture is used. When choosing a solution, special attention should be paid to the indicator strength class (grade), which determines the maximum permissible compressive loads of a fully formed mixture. Expressed in kgf/cm², i.e. how many kg can 1 cm 2 of surface support?
For the most part, the grade of concrete is determined by the proportions of cement, sand (crushed stone, gravel) and water, as well as the conditions under which the solution hardened. In total, there are about 15 strength classes from TM50 (B3.5) to M800 (B60), but in private construction the most The most common brands are M100-M400. Accordingly, M100 concrete is suitable for light structures - garages, bathhouses, equipment, and M400 - for multi-story heavy buildings, for example, made of brick. But in the vast majority of cases, M300 grade concrete is chosen.
Using our calculator, you will receive a calculation of concrete for the foundation (volume, mass). All values will be available directly in the interface - you don't need to switch to other tabs. However, you are required to enter the grade of concrete used.
Calculating cement for your foundation has never been easier with our online calculator. Just fill in the fields in the tool and you will get the required values in the calculation results!
Reinforcement is the second most important component of the foundation (its “bones”), which allows you to compensate and level out the impact of tensile and bending loads. It is a well-known fact that concrete is not flexible and ductile, but it has high compressive strength. In order to combine these qualities and improve the performance characteristics of the foundation, as well as prevent deformation after the construction of the structure, the foundations are reinforced.
Foundation reinforcement represents the creation of a certain type of frame from connected horizontal, vertical and transverse rods. The most significant characteristic of reinforcement is its diameter and its choice depends on the type of soil, temperature characteristics, wall materials and dimensions of the structure being built. It is believed that for light buildings it is optimal to use 10 mm rods, 12 mm for single-story and low-rise buildings made of porous materials, 14 mm for low-rise buildings made of heavy materials, 16 mm for multi-story buildings and difficult soils.
The second important indicator is the tying pitch of the reinforcement. Usually it is selected by eye, based on the total mass of the structure and the type of underlying soil; the value should be in the range of 200-600 mm. The standard spacing used in private construction is 500 mm.
The built-in calculator for calculating reinforcement for the foundation allows you to calculate the number of rods, their total length, weight and volume. The result is provided both when calculating a strip foundation and a monolithic slab.
Our calculator will be useful when calculating the foundation for a house made of aerated concrete, foam concrete, brick and other building blocks!
Calculate the foundation for the house
In modern realities, almost anyone can calculate the foundation for a house - you do not need to have special knowledge and do not need to use the expensive services of specialists. However, before you start construction, you need to understand what type of foundation will be most rational for your site. Let us recall that the physical-geographical location and geomorphological conditions of the area have a direct impact on the type and cost of the future structure.
Factors for choosing the type of base
The soil- the most important factor in the construction of a house; the labor intensity of the process and the cost of constructing the foundation directly depend on its composition. In some cases, it comes to the point that it is more profitable to buy a new plot than to invest in transforming an existing one. Therefore, the very first thing you need to do on a new site is to determine the type of soil.
If you don’t have extra money, then you need to learn how to determine soils yourself. It is important to know that all types of soils are divided into rocky, clayey and sandy. Each type has its own set of unique properties, the most important of which are bearing capacity, heaving and freezing depth.
Groundwater- the second insidious companion of any builder. If you have a high aquifer level, then this is a very bad prospect for the future. In warm regions, endless flooding, dampness, mold and fungi will bother you. The dissolved harsh chemicals will slowly kill your foundation by loosening and dissolving the concrete.
In cold areas, the previous factors act to a lesser extent, but the forces of frost heaving can easily tear apart an improperly constructed foundation in a few winters. Therefore, it is extremely important to build a house on higher ground and avoid low-lying areas, especially if there are watercourses and ponds nearby.
Our articles in the section “ will help you conduct a soil analysis and find out the groundwater level. Foundations, soils, bases" You can calculate loads and other important parameters, according to SNIP, using the appropriate calculators on our website project.
Temperature- combines the two previous factors into a single whole. It is the last decisive factor that can influence the choice of base.
When building a foundation, the most important indicators are the depth of soil freezing and the level of groundwater. In a continental climate (with low temperatures in winter and high in summer), which occurs in most of Russia, every year the soil freezes to a significant depth and then thaws.
If the groundwater level is above the freezing mark, then heaving forces begin to act. The water contained in the soil freezes and turns into ice, thereby increasing its volume.
The power of this process cannot be underestimated, the force with which they can press on the foundation is tens of tons per square meter. Such an impressive impact will easily deform any structure and set it in motion.
Therefore, it is very important to know the standard depth to which the soil freezes annually. By laying the foundation below this level, you protect it from these destructive forces, but at the same time the cost of the foundation increases proportionately.
Types of foundations for a house
Based on these “input” conditions, we can now move on to an overview of the types of foundations. Their classification is based on design features and construction technology. The most popular are strip, monolithic, columnar, pile foundations and their combinations.
Strip foundation
Strip foundation- got its name because of its external resemblance to a ribbon. A monolithic or prefabricated reinforced concrete strip passes under all load-bearing walls of the building, exerting uniform pressure on the ground. One of the simplest and most affordable in private construction.
The labor intensity of the process is minimal, the installation technology is not particularly complicated and is relatively inexpensive. Suitable for most cases in the construction of low-rise buildings, it can easily withstand heavy loads. When the groundwater level is low, a shallow strip foundation is used, and when the groundwater level is high, a deep foundation is used.
In extremely problematic soils, when the tape has to be deeply buried by 2 m or more, the feasibility of using this type of base disappears and other options should be considered.
With us you can perform calculations for shallow and deep foundations. To determine which type is right for you, use our foundation depth calculator.
Monolithic slab
Slab foundation- a monolithic reinforced concrete slab located under the entire area of the building. Due to the large volume of excavation work and the huge costs of concrete, the cost of the structure increases significantly compared to tape. This is one of the most expensive, but at the same time effective types of bases.
Due to its homogeneity and large area of contact with the ground, this type of foundation easily tolerates significant vertical and horizontal loads. ;It is not afraid of the forces of frost heaving and high groundwater levels. It consistently performs on weak-bearing soils, and also withstands heavy houses made of brick and stone.
Columnar foundation
Columnar foundation is a structure made of pillars and ceilings, which is used in the construction of structures made of lightweight materials. ;The foundation structure is extremely simple. Along the perimeter and in places of increased load (most often these are the intersections of walls), pillars are placed, which are connected on top by beams made of wood or metal.
This base has gained wide popularity due to the active construction of houses made of timber and SIP panels. It is economical, reliable and does not require waterproofing work. Protects your home from mold and premature destruction of wood. However, the foundation is extremely demanding on the soil; movement and heaving are strictly prohibited.
Pile foundation
Pile foundation- is a complex of numerous piles that create a stable frame for uniform load distribution across all structural elements. Foundations of this type are a salvation for owners of areas with unstable soils and difficult terrain. In addition to the fact that they allow you to securely fasten the building, they also strengthen the soil itself, preventing movement and landslides.
There are three main types of pile foundations:
- On screw piles;
- On bored piles;
- On driven piles.
Each of them has its pros and cons, but the most common is the first type, as it combines low cost and meets all standards of private construction.
Please indicate the required dimensions in millimeters
X- foundation width
Y- foundation length
A- foundation thickness
H- foundation height
C- distance to the axis of the jumper
A- foundation thickness
H- foundation height
S- step between connections
G- horizontal rows
V- vertical rods
Z- connecting rods
The required amount of cement to produce one cubic meter of concrete is different in each specific case.
This depends on the brand of cement, the desired brand of concrete produced, the size and proportions of fillers.
Indicated in bags.
There is no need to repeat how important it is when designing a house to calculate the amount of building materials for the foundation of the house.
After all, the cost of a monolithic foundation reaches a third of the cost of the house.
This service will make it easier to plan and calculate the foundation of a house. It will help you calculate the amount of concrete, reinforcement, and formwork boards for installing a strip foundation.
What you can find out:
Footing area (for example, to determine the amount of waterproofing to cover a finished foundation)
The amount of concrete for the foundation and floor slabs or pouring the basement floor (it will be fun when, due to a simple error in multiplication, there is not enough concrete)
Reinforcement - quantity of reinforcement, automatic calculation of its weight based on its length and diameter
Formwork area and quantity of lumber in cubic meters and pieces
Area of all surfaces (for calculating foundation waterproofing) and side surfaces and base
Added calculation of the cost of foundation building materials.
The program will also draw a drawing of the foundation.
I hope that the service will be useful to those who build the foundation with their own hands and construction specialists.
concrete composition
The proportions and quantities of cement, sand and crushed stone for preparing concrete are given by default as a guide, as recommended by cement manufacturers.The same goes for the price of cement, sand, and crushed stone.
However, the composition of the finished concrete greatly depends on the size of the crushed stone or gravel fractions, the brand of cement, its freshness and storage conditions. It is known that during long-term storage, cement loses its properties, and with high humidity, the quality of cement deteriorates faster.
Please note that the cost of sand and crushed stone is indicated in the program for 1 ton. Suppliers announce the price per cubic meter of sand, crushed stone or gravel.
The specific gravity of sand depends on its origin. For example, river sand is heavier than quarry sand.
1 cubic meter of sand weighs 1200-1700 kg, on average - 1500 kg.
With gravel and crushed stone it is more difficult. According to various sources, the weight of 1 cubic meter is from 1200 to 2500 kg, depending on the size. Heavier - smaller.
So you will have to recalculate the price per ton of sand and crushed stone yourself or check with sellers.
However, the calculation will still help you find out the approximate costs of building materials for pouring the foundation. Don’t forget the wire for tying reinforcement, nails or screws for formwork, delivery of building materials, costs for excavation and construction work.
Note: accurate concrete calculations are carried out for dry sand and crushed stone; if they are moistened, the volume of water will be different. Here you need to experiment with the volume of water.
Foundation base width A- depends on the weight of the building, the strength characteristics of the soil under the building, etc. It is recommended to accept based on the calculation results.
The width of the roof must be increased.
H- height of the foundation. Depends on the degree of soil subsidence (the more subsidence the soil, the higher)
H.C.- the height of the foundation (basement) above ground level. The required formwork area depends on it. The excess level should not be less than 200 mm.
The depth of the foundation into soil subject to frost heaving (loams, clays) should be no less than the depth of soil freezing in the given region. The depth should be no less than the thickness of the plant soil layer (30-50 cm)
In underground soils, the walls of the trench are unstable and will crumble.
Horizontal rows of reinforcement are made from “working” reinforcement with a diameter of more than 10 mm, and vertical rows are made from “structural” reinforcement with a diameter of 8-10 mm of smooth or periodic section.
The pitch of vertical reinforcement is taken from the conditions of non-sagging of the working reinforcement of the upper row.
It is prohibited to insert vertical reinforcement into the ground or install it on pieces of crushed stone and other improvised objects. The reinforcement frame must either be suspended or installed on specially made concrete support cubes.
The distance between the ends of the reinforcement must be at least 15 mm.
Since a strip foundation for a house is a closed loop of reinforced concrete beams erected under all the load-bearing walls of the house, choose one of the eight proposed standard foundation options based on how many load-bearing walls are planned in the house.
Option No. 1 is relevant if construction is planned without internal supporting walls, No. 2 if an internal supporting wall is needed, options No. 3-8 if more load-bearing walls are needed in the house.
Fill in the dimensions in millimeters:
X– The width of the foundation depends on your wishes and the possibility of construction on the site. Parameter value X take more than the width of the walls (i.e. the distance between the outer planes of the walls) by approximately 100 mm on each side to allow finishing. When you select the option X SP 50-101-2004 “Design and installation of foundations and foundations of buildings and structures” should be taken into account.
A shallow strip foundation is suitable for all types of soil except subsidence, peat bogs and water-saturated soils. And it is often optimal for frame, timber, and brick houses.
Y– the length of the strip foundation is determined by the length of the house.
H– The height of the foundation depends on the depth of the foundation (shallow from 0.3-1 m, buried up to 2-3 m) and the elevation above ground level. The foundation must be made below the freezing line and above the groundwater level. If it is not planned to equip auxiliary premises in the basement, then a height of about 150-300 mm above ground level is sufficient, and if the base is to be used, more. The height of the strip foundation H is taken from 0.3 m for light houses and reaches about 4 m for heavy stone ones. The key to a reliable foundation is an individual project that takes into account the characteristics of the soil on the site; height of groundwater; the depth of soil freezing in your region; the weight of the house (i.e. the load on the foundation from the weight of the walls, ceilings and roof).
A– thickness of the foundation strip, i.e. the distance between the outer and inner planes of the foundation depends on the thickness of the walls being built (accepted to be 100-150 mm more). Approximate values of the thickness of the strip foundation for outbuildings (shed, bathhouse, garage) are in the range of 250-400 mm; for a 1-story light (for example, frame) house 300-650 mm; A 2-storey brick house is built on a foundation 650-750 mm thick.
WITH– the center-to-center distance between the foundation lintels (relevant for options No. 2-No. 8) depends on the features of your project.
Reinforcement parameters:
G– Number of horizontal reinforcing rows, for strip foundation G=2. It may be more depending on the magnitude of the existing loads. It is recommended that you familiarize yourself with SP 63.13330.2012. The capabilities of the online calculator allow you to calculate up to 10 rows of reinforcement.
V– The number of vertical rods connecting the reinforcing belts to each other can be from 1 to 5.
Z– The number of connecting rods is taken from 1 to 5.
S– Step length is the distance between adjacent vertical reinforcing straps. Optimal value S 300-500 mm.
Weight of 1 m reinforcement depends on its diameter. The approximate weight of one meter of different diameters of iron reinforcement is given in the table.
| Diameter fittings, mm |
Weight of 1 linear meter of reinforcement, kg |
| 6 | 0,222 |
| 8 | 0,395 |
| 10 | 0,617 |
| 12 | 0,888 |
| 14 | 1,21 |
| 16 | 1,58 |
| 18 | 2 |
| 20 | 2,47 |
| 22 | 2,98 |
| 25 | 3,85 |
| 28 | 4,83 |
| 32 | 6,31 |
Formwork parameters:
Board thickness for assembling formwork, it is taken from 25 mm to 50 mm on the basis that the thicker the better (but also more expensive).
Board length. This parameter is usually selected around 4000-6000 mm, depending on the availability of lumber in the warehouse and the price of the formwork board.
The board is wide. To make formwork, use an edged board (possible on one side) with a width of 100-200 mm.
Installation of formwork requires care and a responsible attitude of performers in order to ensure the correct geometry of the future foundation.
It is important to strengthen the assembled formwork with wire so that it does not fall apart due to the weight of the concrete, cover the inside with plastic film, this will prevent concrete leakage and make it possible to reuse the boards for construction purposes.
Concrete composition parameters:
Bag weight, kg– here enter how much 1 bag of cement weighs in kilograms.
Concrete proportions by weight. The approximate ratio of components for a concrete mixture is 2-3 parts sand for 1 part cement, 4-5 parts crushed stone, 1/2 part water (the mixture should be plastic and not too liquid). However, depending on the required grade of concrete, the grade of cement used, the characteristics of sand, crushed stone, the use of plasticizers or additives, the proportions may vary. Standard rates of cement consumption for the preparation of prefabricated and monolithic concrete, reinforced concrete products and structures are regulated by SNiP 5.01.23-83.
Enter prices for building materials: cement (per bag), sand (per 1 ton), board (per 1 cubic meter) and reinforcement (per 1 ton).
This construction calculator will:
- calculation of the base area of the strip foundation and the required volume of concrete for pouring it;
- calculation of the formwork area (i.e. the area of the side surfaces) and the required amount of lumber for the formwork of a strip foundation and their price (if the height of the slab is not a multiple of the height of the board, then the number of boards is calculated taking into account covering the entire height of the slab);
- calculation of the number of bags of cement, tons of sand and crushed stone for a strip foundation and the cost of these components of concrete for pouring;
- calculation of the required reinforcement of a strip foundation, namely the number of horizontal, vertical and connecting rows of reinforcement, its length, weight and cost of reinforcement.
The calculator will also calculate the final cost of constructing a strip foundation, which will give an idea of the level of material investment in the foundation of your home and allow you to make an informed decision about the feasibility of this type of foundation. You can also calculate other foundation options using our calculators and choose the optimal solution.
Calculating the foundation for a house is the most important stage of construction, which would be better entrusted to professional design engineers.
However if the construction is planned no higher than two floors and you are confident in your abilities, then you can take on the calculation yourself.
The main thing is to take everything into account.
Main functions
The foundation is the main supporting structure of the house.
His main tasks:
- Support the weight of the entire building.
- Evenly distribute the load on the ground.
- Prevent flooding with melt and groundwater.
Types of foundation for a house
Before calculating the foundation of the house, you need to decide what type of foundation will you use for your building?.
According to the type of construction they are divided into:
- tape;
- slab;
- columnar;
- pile
A monolithic reinforced concrete slab is called slab, laid in deep and leveled soil. The rare use of this type of base, despite the possibility of using it on unfavorable soil, due to high cost.
Columnar- This is a structure of pillars connected by beams. Although this is the cheapest option, it is recommended to use it for soils not subject to temperature changes. Besides, he can only support a small wooden house.
Foundation on piles can be used on soft soils or during the construction of a multi-storey building. However, the need to use a lot of equipment significantly increases the cost of the entire building.
Laying depth
The depth indicator is directly dependent on the following factors:
- ground water level;
- depth of soil freezing (data by region is presented below);
- condition of soils, their heaving, subsidence, etc.;
- height of the building being constructed;
- design features (for example, the planned basement will significantly deepen the foundation);
- the presence of underground communications, buildings and structures in the immediate vicinity.
Base load calculation
When starting to calculate the foundation for a house, first calculate the load it will hold.
To do this, calculate the surface area of all walls, floors and roofs, multiply the area of each structure by its specific gravity, which can be taken from the table below.
Don't forget also that Furniture, household appliances, things and, of course, people will later be added to the weight of the house. All this also needs to be taken into account when calculating the load on the base, so it’s better to consider it with a margin.
Ground Load Calculation
The next step in the calculations is to determine the load on the ground. To understand whether the soil can support the building, it is necessary to calculate the weight of the foundation of the house.
For this calculate the volume of the base, using mathematical formulas, and multiplying it by the density of concrete (average densities of different types of concrete can be found in the table below).
Then we will carry out simple calculations using the formula:
(VF+VD)/Ppf, where VF is the weight of the foundation, VD is the weight of the house, Ppf is the area of the base.
Thus, we have determined how many kilograms of load should 1 cm2 of soil bear?.
Now it is important to correlate the required soil load with the permissible values indicated in the table.
If the load obtained during the calculations is greater than the calculated resistance of a given soil type, it is necessary to increase the supporting area of the house, namely:
- The tape can be made expanded towards the base ( cross section looks like a trapezoid).
- Increase the width of the parallelepiped foundation.
- For a columnar base you can increase the diameter of the pillars or their number.
Important! As the size of the base increases, the structure of the house will become heavier. Therefore, be sure to re-calculate the load on the ground! 
Calculation of the amount of concrete, wire and reinforcement
Having decided on the size of the foundation, you need to calculate how much reinforcement, wire and concrete will we need?.
With the last one everything is simple. The volume of concrete is equal to the volume of the foundation, which we already found when we calculated the load on the ground.
But what metal to use for reinforcement has not yet been decided. Here it all depends on the type of foundation.
Reinforcement in strip base
For this type of foundation, only two reinforcement belts and reinforcement up to 12 mm thick are used. Horizontal longitudinal reinforcement bars are subject to greater loads than vertical or transverse ones.
Therefore, ribbed reinforcement is placed horizontally, and smooth reinforcement is placed vertically.
Length of ribbed reinforcement It’s easy to calculate if you multiply the total length of the base by the number of rows of rods. If the foundation is narrow (40 cm), two longitudinal rods for each belt are sufficient. Otherwise, the amount of reinforcement in the belt will have to be increased.
Transverse rods are installed every 0.5 m, retreating 5-10 cm from the edge of the foundation. We determine the number of connections by dividing the entire length of the foundation by 0.5 (the step between intersections) and adding 1.
To find smooth reinforcement length required for one intersection, we use the formula:
(ShF - 2*ot)*2 + (VF - 2*ot)*P, where ShF and VF are the width and height of the foundation, from is the offset from the edge of the foundation, P is the number of rows of reinforcement in the belt.
After this, we multiply the two resulting values, getting the amount of smooth reinforcement required for the foundation.
Costs of binding wire for foundation– this is the product of wire consumption for one bundle (30 cm), the number of bundles at one intersection (equal to the number of rows of reinforcement multiplied by 4) and the number of connections.
Reinforcement in slab foundation
For slab base ribbed reinforcement is used 10 mm thick or more, laying it in a grid, in increments of 20 cm.
That is, for two reinforcement belts you will need:
2*(ShF*(DF/0.2+1) + DF*(SF/0.2+1)) m reinforcement, where ShF is the width, DF is the length of the foundation.
To connect two planes of the frame, you need each connect the intersection of the upper grid with the corresponding intersection of the lower one.
Taking into account the thickness of the slab and the distance of the frame from the surface of the slab, we determine the amount of reinforcement required to connect the belts using the formula:
((DF/0.2+1)*(SF/0.2+1))*(TP-2*from), where TP is the thickness of the slab, from is the distance from the surface.
It is enough to add the two resulting numbers to know how much reinforcement is needed for a slab foundation.
The length of the knitting wire is calculated based on the formula:
General estimate
To summarize, so that the entire theory presented above becomes a little clearer, we present example of calculating the foundation for a one-story house.
The building measures 6x10 m, with an internal six-meter wall. At the same time, the height of the first floor is 3 m, and the height of the attic is 2 m.
As you can see, calculating foundations is not such a complex science that one should refuse to build on their own, and this example of calculating a foundation is given here as the main evidence.
