Rules for the selection, calculation and installation of reinforcement for the foundation

In private construction, many developers do not pay due attention to the creation of reinforcement for the foundation, believing that concrete is able to withstand loads. Also, inexperienced builders do not pay attention to the brand, type and class of reinforcement bars.

Foundation reinforcement is a necessary element of the components of the reinforced concrete foundation of a house. It allows you to increase the strength of the foundation of the house, since concrete alone does not cope well with the impact of the load. When pouring a concrete mixture, steel reinforcement bars in the concrete mass are positioned so that the main load falls on them.

Selection rules

The reinforcing rods at the base play an important role - they create rigidity, thereby preventing crashes. To perform this function, it is necessary to make a high-quality reinforcing frame , which will ensure the safety of the foundation.

During construction, it is necessary to select the material based on the diameter and type of reinforcement.

Many construction experts recommend using steel rods.

And although manufacturers of fiberglass materials talk about the possibility of replacing steel, experienced engineers are distrustful of the statement and are strongly testing notched steel rods.

An important point when choosing a material is the diameter of the rods. For frame structures, you can purchase reinforcement with a 10-12 mm cross-section, and for the construction of powerful structures, denser ones - 14-16 mm.

You should also choose a metal that has anti-corrosion properties. This will ensure resistance to aggressive external environments.

Important! To obtain maximum functional returns, when building a strip foundation, it is better to create the frame in 2 levels with the installation of intermediate vertical rods.


During installation, various types of steel rods are used, which perform a specific function. For ease of selection and simplification and creation of a unified system, it was distributed according to classification criteria.

Classification featureCharacteristicKinds
By type of materialThe raw material from which the fittings are created.Steel, composite.
By surface typeVarieties of steel sections.Ribbed, smooth.
By method of applicationFunctionality of steel during foundation creation.Tense and non-stress.
By locationMounting reinforcement when creating a foundation.Vertical, transverse.
By labelingDesignation of elements included in steel.A1, A2, A3, A4, A5, A6.

This distribution will help you choose the required type of material to create a durable complex.

Most often, when constructing a strip foundation, prestressed steel of class A3 is used. It not only ensures the strength of the structure, but also reduces the load on the structure.

Reference! This type of steel contains anti-corrosion substances, thanks to which the metal is protected from aggressive influences. Composite reinforcement is not suitable for creating a foundation. It is used for the construction of walls, as it has lower endurance.

By material type

One of the most important classification features is the type of reinforcement. After all, the material from which the rods are made is of great importance when used in installation.

There are not many types of rods, but they have distinctive features, namely:

  1. Steel reinforcement. Rods, smelted in the form of metal rods, with a diameter of 6 to 50 mm. This type is used in the construction of the base of a building, since the components of the reinforcement create safety from collapse.

  2. Composite. Reinforcement, which includes special fibers: glass, carbon, aramid, basalt. These types of materials have high resistance to substances. The constituent raw materials are characterized by their name:
      fiberglass - unique in lightness and strength, as well as a fracture limit that is 3 times higher than that of steel;
  3. basalt-plastic - a significant difference in resistance to aggressive environments and fire resistance;
  4. carbon fiber - characterized by low thermal conductivity, high strength and resistance to aggressive influences, and is also able to withstand extremely low temperatures;
  5. glass-reinforced polyethylene terephthalate - has the same properties as the previous ones, however, the prices are low due to the low cost.

It is important to know! Composite reinforcement is necessary for laying walls in layers and for repairing the surface of brick buildings. In addition, such metal is used to create a foundation in winter, since special substances are added to the solution to quickly harden solutions that can deform the steel.

By type of production

There are 3 types of rods involved in creating the foundation, which are made in different ways.

Hot rolled (rod)Produced using high temperature (up to 920 degrees)A
Cold drawnMade from carbon metal under cold temperature pressureVR
RopewayMade from wire. They are used for large span structures that exist under pressure (water, gases, solids). TO

The uniqueness of cold-drawn reinforcement is its thinness and lack of deformation after casting. However, the first type of metal is in greatest demand.

By surface type

The use of reinforcement depends on the cross-sectional surface. There are such surface sections:

  1. Smooth surface . This circular point is used for distribution installation. It is usually used to screed floors or paving slabs or to strengthen fasteners.
  2. Ribbed. Includes various surface appearances, namely:
      ring-shaped - limits the strength of the metal, adheres well to cement;
  3. crescent-shaped - provides flexibility when working with metals;
  4. combined - combines the functions of metal with a ribbed surface.

These types are intended for screeding the foundation.

By steel class and grade

Metal rolling is produced in accordance with GOST and is marked. The designation of the symbols characterize the steel.

Marking ClassCharacteristic
A1The marking was used during the USSR, but is now irrelevant. Not subject to welding.
A2Not subject to welding.
A3The most common type of steel. Has a ribbed surface. This type of reinforcement is characterized by durability, endurance and fire resistance.
A4Withstands heavy loads, widely used for house foundations.
A5They are not in demand because they have a high price. It is used for the construction of large factories, large-scale warehouse workshops.

The letter C may sometimes be added to the marking. This means that the steel is welded for construction, and the letter K indicates that the reinforcement contains substances that guarantee protection against destruction of the metal when exposed to the environment.

By location and purpose

This classification feature includes 2 types of fittings. These include:

  1. Working - guarantee the strength and rigidity of structures, take on the weight of the structure. This type is located longitudinally (horizontally).
  2. Clamps - used for installation and connection. This type is installed vertically and transversely in structures.

When purchasing steel, you should consider its location in the building. According to the method of application, there are 2 types of reinforcing mesh.

TensileIt is distinguished by increased durability and endurance.
Has a diameter from 5 to 40 mm. Ensures the safety of the concrete structure under strong tension.
UnstressedIt is not intended to provide rigidity, but is used as a mounting element to protect the structure from cracks.

In a strip foundation, both types of reinforcement are used, however, a component of the reinforcing structure is filled with prestressing steel, as it can withstand heavy loads.

Important! The non-tensioned metal should be located at a height of one row to reduce the load on the building, welded to the longitudinal steel elements.

To size

The size of the reinforcement is determined by its diameter, which is prescribed by GOST. The diameter of the rods can be purchased from 5 mm to 50. The variety of sizes allows the use of steel of the desired size for a variety of purposes. Any type and type of steel is divided by size.

Brand of reinforcement for strip foundation

To reinforce the strip base, rods of class A-I and A-III , which are produced by the hot-rolled method.

Reinforcement A1 (A240) has a smooth lateral surface and is used for longitudinal piping and transverse connection of structures, where tensile loads are minimal. It has a yield strength of 240 N/mm2.

Ribbed products that have greater reinforcement strength are classified as class A-3 (A400) . A3 reinforcement has a round cross-section and a side surface with ribbed projections that serve to improve adhesion to concrete mortar. This brand of reinforcement has a yield strength of 390 to 400 N/mm2, which makes it possible to stretch by 25 mm while maintaining integrity. A high degree of yield strength is especially important for the material for longitudinal reinforcement , therefore it is made of A400 steel. In the reinforcement weights table you can find out the weight and cross-sectional area.

According to European standards, A500C reinforcement is used for the greatest reinforcement of the frame, where the letter C indicates the permissibility of welding products without loss of technological properties.

A500C reinforcement has a yield strength of 500 N/mm2 and is more durable compared to A400 products with the same cross-sectional diameter.

Which one is most often used and why?

A strip foundation is a reinforced concrete section along the perimeter of the building on which the walls are built. The strength of the entire building depends on the quality of the constructed platform.
Reinforcement in combination with concrete provides strength and compression of the structure.

For small one-story or two-story houses, metal alloys are most often needed, the diameter of which varies from 6 to 14 mm, which is tied with steel wire for strengthening.

The necessary calculation of the required amount of materials is carried out by specialists during the design of the facility. However, you can calculate it yourself. To do this, take the perimeter of the building, add to it the length of the walls that are involved in laying the strip foundation and multiply the result by the number of rods in the reinforced box.

To calculate the diameter of the reinforcement, it is necessary to calculate the cross-sectional area of ​​the vertical bars in the platform by multiplying the length of the building by its width.

Example: The width of the strip foundation is 20 cm, and the height is 60. This means the cross-sectional area is 1000.

However, the area of ​​the vertical rods should be 0.1% of the total horizontal section of the foundation. That is, it is necessary to multiply the previously obtained result by 0.1%.

That is, 1 cm. In a special table you can determine the required diameter.

If it is not possible to purchase the required length of reinforcement, you can install them yourself.
However, the rods must overlap each other by at least 1 m to avoid damage. In addition, the following factors must be taken into account when calculating:

  • there is no need to bury the reinforcement into the foundation, since the divergence zone is located on the surface.
  • For transverse and vertical finishing zones, you can use smooth reinforcement. In this way, the load on the structure can be reduced.
  • the distance between elements should be 150-400 mm.

Such recommendations will help reduce the load and avoid troubles during construction.

You can watch the video for more details:

Features of the metal frame

The reinforcing mesh in the foundation is a connecting element.
The use of metal rods for the construction of the foundation is a fairly well-known and traditional technology. They are used for small-sized and large-sized buildings for various purposes.

During the process of pouring the foundation, a mesh of metal reinforcement is a kind of connecting element that allows the concrete solution to be distributed more evenly and takes on all external loads on the foundation, especially during the stabilization process.

The advantages include sufficient strength and ductility, availability on the market, and ease of assembly of the structure. Disadvantages include corrosion of metal rods when moisture enters cracks in the foundation and gradual destruction of individual parts of the foundation.

When choosing metal reinforcement for the foundation of a house, you need to decide on its type, class and source material.

What are the consequences of making the wrong choice?

The selection of reinforcement and installation during foundation laying is one of the critical stages.

Threatens with dangerous consequences:

  1. poor quality material,
  2. incorrect installation
  3. failure to execute the bookmark algorithm.

First of all, this is a lack of strength, which can lead to the destruction of the entire residential complex. In addition, the durability of the structure depends on the condition of the foundation.

Attention! It is necessary to carefully calculate all construction elements: the consistency of the mortar, the diameter and quantity of reinforcement, the distance between the gaskets, etc., otherwise the consequences may threaten not only the health, but also the lives of the inhabitants of the house. If the foundation is laid correctly, a building can exist for more than 150 years.

( 2 ratings, average 4 out of 5 )
Did you like the article? Share with friends: