Faucets

Correct knitting of reinforcement for a strip foundation. Knitting reinforcement - making a strong frame Should I connect the foundation of a house to a new one?

Construction of a house begins with laying the foundation. The main requirement for a concrete foundation is its strength. It is achieved by laying a frame of reinforcement bars tied together inside the concrete. Such a frame is called reinforcing. This article will discuss such an important stage of construction work as tying reinforcement for the foundation.

It is necessary to first consider what methods of tying reinforcement for the foundation generally exist. They differ from each other by type:

tool;
material;
knitting patterns;

By instrument type- this can be either knitting reinforcement for the foundation manually or using a special tool. As the latter, special crochet hooks, screwdrivers, special guns, produced just to perform this operation.

As a material which is used to connect reinforcement bars to each other used:

knitting wire- This is the most common and reliable technology for tying reinforcement for the foundation, because it is performed with tying a knot.
paper clips- are wire tacks, which, unlike ligation with knitting wire, are made without tying a knot.
clamps small size made of plastic- this new material has become widespread due to its ease of installation and high knitting speed, and besides, it is not afraid of corrosion. However, such a bundle of reinforcement for the foundation causes a certain skepticism among professionals. Read more.
clips— made in the form of latches that fix adjacent rods to each other.
welded joint- this old method has not become widespread, since the welded joint, due to its fragility, is susceptible to cracking during concrete pouring and does not have the necessary reliability. To perform a high-quality welded joint, you need a highly qualified welder.

Required wire

When choosing wire, the following factors must be considered:

Manufacturing accuracy class. The accuracy class is determined by the production method. There is a wire of a higher accuracy class, its deviation of the actual size, diameter, from that declared by the manufacturer along the entire length of the wire is less than that of a wire of a lower accuracy class. However, for knitting reinforcement, the accuracy class is not particularly important.
Wire rolling method. There are two types of rolled products: cold-rolled and hot-rolled. Cold-rolled steel is rolled out from blanks by presses without heating. With the hot rolling method, rolled steel is rolled out in a heated state, which gives greater strength.
Which tensile strength group does it belong to? wire (there are the first and second groups);
Degree of corrosion resistance. On this basis, there is only one difference - whether there is a galvanized coating on the wire or not.

The criterion for choosing wire is very simple, you need wire, which is called “knitting”. It has a full set of necessary characteristics: sufficient softness with the declared strength, abrasion resistance and reliability when fastened.

Galvanized wire is considered overkill.
The optimal diameter of the knitting wire is 1.2-1.4 mm. A wire with a diameter of 1.6-2 mm takes a lot of force, as a result of which construction slows down, and the piece is too weak, it will simply burst.

Attentively you need to ensure that the connection of the reinforcement remains rigid after tying the knot: during pouring, the frame must remain motionless. This will ensure the reliability of the structure after hardening.

You need to check the rigidity of the connection of the reinforcement by touching the rods - if they are rigidly fixed, they will not move, which means everything is in order. You should not test the strength of the knot itself, otherwise there is a risk of loosening the binding.

The length of wire recommended for one knitting point is from 30 to 50 cm. The wire itself is extremely cheap - about 50 rubles. for 100 meters. To avoid running out of it at the wrong time due to loss or excessive consumption, it is recommended to buy it with a double supply. 100 rubles for 200 meters is quite inexpensive.

How to bend reinforcement correctly, all the ways

You should choose how to bend foundation reinforcement based on its diameter: with your own hands It’s quite easy to bend a small diameter, but for thicker reinforcement you’ll have to use special devices, homemade or specialized.

Among homemade devices, two methods are common. The first is when an ordinary pipe of suitable diameter is installed vertically and its base is poured with concrete so that it stands firmly.

The fittings are inserted inside all the way, and now the end protruding from the pipe can be bent by simply leaning on it. If this presents certain difficulties, then a second pipe is additionally put on the free end of the reinforcement, and now, due to the increased leverage, the thick reinforcement is easily bent.

Welding is also often used. By softening a section of the rod with heat, it becomes easy to bend. The same is done with a blowtorch and a hammer. After heating the bend point with a lamp, bend the reinforcement with a hammer.

The most radical way is to make an incision with a small grinder and then bend it completely using available tools.

It should be noted that methods using welding and notching are not the best - at the bend, in these cases, the strength of the reinforcement is reduced by up to 10%.

Crochet

The design of the hook for these purposes may be different, but this is not so important. The meaning lies in the presence of a hook as such, because it is used to thread the wire. The rules for tying reinforcement for the foundation are shown schematically in the figure.

Pay attention to the sequence of actions:

Bend the wire in half;
Follow the arrow, as in the figure, bring it into position for threading;
Insert the hook into the loop that will now be wound;
Place the hook loop inward between the free ends of the wire;
Without removing the hook, twist until tightened, but do not pinch;
Ready!

There are motorized screw hooks in which the wire is tightened by rotating a screw. It turns out very quickly and conveniently.

For strip foundation

The strip foundation reinforcement has two patterns for laying rods:

4 rod system: two at the base of the foundation, two at the top (used if the width of the foundation does not exceed 50 cm),
6 rod system: an additional longitudinal rod is placed between the two main ones (used in cases where the foundation width is more than 50 cm).

Bent reinforcement is laid at the corners, and the ends should protrude from the corner by at least 40 cm. Reinforcement connection nodes should be located apart from each other at a distance of no more than 60 rod diameters. For example, if 12 mm reinforcement is used, then the strapping should be every 72 cm or more often.

For columnar

This is a foundation that is placed on pillars that act as piles.
A tied one is placed inside the pillars before pouring. The tying of reinforcement for a columnar foundation is the same as for a strip foundation - either 4 rods, or 6 for large columnar foundations.

For vertical rods in this type of foundation, 12 mm reinforcement is used, since this is a vertical foundation. The cross rods can be thinner and smoother.

For wooden houses, it is allowed to use longitudinal and vertical reinforcement thinner than 12 mm. Sometimes, for the foundation of small wooden buildings, a welded frame is constructed from vertical rods connected with hoops like a barrel. This is incorrect, because with this bonding method you can only use welding, and this is not a completely reliable method. We have already talked about this above.

For slab

A reinforcement frame for a foundation can take the form of a two-dimensional plane, a mesh formed from reinforcement bars. The second option is volumetric, in the form of two meshes of intersecting reinforcement, located one above the other and connected by transverse rods.

Reinforcement - from 12 mm and above, up to 16 in private housing construction. The mesh cell size is 200x200 mm. The distance from the lower reinforcement belt to the pillow (or insulation) is 50 mm. The top belt is also protected from external influences by a 50 mm layer of concrete.

Cost calculation (price for work and materials)

Let's take as an example a strip foundation 10 by 10 meters. This is the perimeter of the house. In addition, there will be a foundation for internal load-bearing walls - two walls of 10 meters each. It turns out 60 m.p. foundation.

How much knitting wire will be required with the right approach?
Let's say the foundation is less than 50 cm wide - it will use a scheme with four longitudinal rods. In this case, in 1 linear meter of the foundation the following will be used:

4 longitudinal rods. That means at 60 mp. will be 240 meters.
4 vertical. With a foundation height of, say, 50 cm, their height will be no more than 45 cm.
4 x 45 cm = 1.8 m. 60 meters of foundation - 108 m.
4 transverse. With a foundation width of 45 cm, the width of the cross sections will not exceed 35 cm.
4 x 35 cm = 1.40 m. 60 meters of foundation - 84 m.

How much is it?

For longitudinal rods we use 12 mm reinforcement costing 25-30 r/m.p. 240 x 35(30) =6000 (7200)
For vertical and transverse rods, take 6-8 mm at a cost of 12-16 r/m.p. (108+84) x 12(16)=2304 (3072)

So, the purchase of reinforcing rods for this foundation will cost from 8304 to 10072 rubles.

Now let's calculate the required quantity wire. 4 ties for a 4-bar foundation per 1 m.p. This, based on a maximum consumption of 50 cm per tie, is 2 meters of wire per meter of structure. We have 60 meters, so we need 120 meters of wire.

Attention: Wire is sold in kilograms. It is necessary to convert from meters to kg.

1 m of wire with a diameter of 1.2 mm weighs 9 grams, respectively, 120 m of wire with a diameter of 1.2 mm weighs about 1 kg, which costs about 50 rubles. The wire is cheap, so it can and should be taken with a double reserve of 240 meters for 100 rubles. All that remains is to calculate the cost of installation and knitting of the frame. As a rule, it is not calculated separately and is included in the total cost of pouring the foundation. In the regions, such work is cheaper, but the price range is approximately the same - 1000-2000 rubles per cubic meter. This price includes the construction of a trench, installation of formwork, binding of the frame, pouring concrete and removing the formwork.

The total length of the foundation we are calculating is 60 meters, width 0.4 m, height 0.5 m. Let's calculate the volume: 60 x 0.4 x 0.5 = 12 m3. With this volume, the cost of foundation work will be 12,000 - 24,000 rubles.

Useful video

How to knit reinforcement in the video below:

In contact with

Concrete can withstand bending forces well, but cannot cope with bending on its own. To ensure load-bearing capacity, they reinforce the foundation with their own hands. This applies to a greater extent to strip and slab structures. Metal is placed in piles and pillars more for structural reasons than for real necessity.

Reinforcement rules

Reinforcement of strip foundations and any other is carried out taking into account the following rules:

for working reinforcement, rods of class not lower than A400 are used;
It is not recommended to use welding to connect the rods, as it weakens the cross-section;
It is mandatory to tie a metal frame from reinforcement at the corners; welding is not allowed here;
Even for clamps, smooth reinforcement is not recommended;
it is necessary to strictly observe a protective layer of concrete equal to 4 cm, this will protect the metal from corrosion (rust);
when making frames, the rods are connected in the longitudinal direction with an overlap, which is taken to be equal to at least 20 rod diameters and at least 25 cm;
if metal is placed frequently, it is worth controlling the size of the aggregate in the concrete: it should not get stuck between the rods.

Example of placement of a reinforcing frame
in a strip foundation

A properly prepared reinforcement frame is half the success. It is he who will save the foundation in case of uneven deformations that create bending loads. It is worth considering the issue in more detail using the example of a do-it-yourself strip foundation.

What reinforcement is needed for the structure?

Reinforcement of a strip foundation requires the presence of three groups of rods:

workers who lay along the belt;
transverse horizontal;
transverse vertical.

Transverse reinforcement under a strip foundation is also called clamps. Its main purpose is to connect the working rods into a single whole. Reinforcement of strip foundations is carried out in strict accordance with regulatory documents. What reinforcement is needed for the foundation? To give an accurate answer, complex calculations are performed.

In order not to hire professionals, you can get by with a simplified option. The technology for reinforcing a strip foundation for a small house allows you to assign sections constructively. This is due to the fact that the tape takes up relatively small loads and works primarily in compression.

To make a reinforcing frame, constructive, that is, minimum permissible, section dimensions are used:

For working reinforcement - 0.1% of the cross-sectional area of the foundation for the house. Moreover, if the side of the tape is 3 meters or less, the minimum acceptable value is taken to be 10 mm. If the side of the building is more than 3 m long, then the diameter of the working reinforcement cannot be less than 12 mm. It is not permitted to use rods with a cross-section larger than 40 mm.
Horizontal clamps cannot be less than one quarter of the working diameter. For design reasons, a size of 6 mm is prescribed.
The diameter of the vertical reinforcement depends on the height of the tape for the foundation of the house. For shallow-depth ones, the dimensions of which are 80 cm or less, rods from 6 mm are suitable.

The rules for reinforcing a deep-type strip foundation provide for the use of rods of 8 mm or more.

Scheme of typical sections of reinforcement bars

If a brick building is being built, it is worth laying reinforcement with a small margin. This option will give confidence in the reliability of the design.

Knitting reinforcement

The strip foundation reinforcement scheme involves connecting the rods using the bonding method. A bonded frame has greater strength compared to a welded one. This is because the likelihood of burning through the metal increases. But this rule does not apply to factory-made elements. Outside the construction site, it is possible to connect parts without significant loss of strength.

Places for tying reinforcement

To increase the speed of work, it is allowed to reinforce the foundation in straight sections by welding. But corners can only be reinforced using binding wire. These sections of the structure are the most critical, so there is no need to rush.

Before knitting reinforcement for a strip foundation, you need to prepare materials and tools. There are two ways in which metal bonding is performed:

special hook;
knitting machine (gun).

The first option is available, but is only suitable for small volumes. In this case, laying reinforcement in a strip foundation will take a lot of time. For connection, annealed wire is used, the diameter of which is 0.8-1.4 mm. The use of other materials is not permitted.

Scheme of tying reinforcement for a strip foundation

To build your home, you need to be patient and attentive. You should not save time and money, as this can cause trouble during operation. There should be no problems connecting the rods along the length. In this case, the process is quite simple; it is only important to maintain the minimum amount of overlap.

But how to properly knit reinforcement for a strip foundation in the corners? There are two types of corner joints: between two perpendicular structures and at the junction of one wall to another.

Both options have several technologies for performing work. For corner walls use the following:

Hard paw. To perform the work, a “foot” is made at the end of each rod at a right angle. In this case, the rod resembles a poker. The length of the foot should be at least 35 diameters, it is better to assign more. The bent part of the rod is attached to the corresponding perpendicular section. Thus, it turns out that the external frame rods of one wall are connected to the external ones of the other wall, and the internal ones are welded to the external ones.
Using L-shaped clamps. The principle of operation is similar to the previous option. But in this case, they do not make a foot, but take an L-shaped element, the side of which has a length of at least 50 diameters of the working reinforcement. One side is tied to the frame of one wall, and the other to the perpendicular frame. In this case, the internal rods must be connected to the external ones. The pitch of the clamps should be three quarters of the height of the basement wall.
Using U-shaped clamps. For the corner you need two elements, the length of the sides will be 50 diameters of the reinforcement. Each of the clamps is welded to two parallel rods and to one perpendicular rod.

How to properly reinforce a strip foundation at obtuse angles. To do this, the outer rod is bent to the required degree value and an additional one is attached to it as reinforcement. The internal elements are tied to the external.

Scheme of correct and incorrect reinforcement of obtuse angles

To lay reinforcement at the junction of one wall and another, use approximately the same methods as in the previous case:

overlap;
L-shaped clamps;
U-shaped clamps.

The amount of overlaps and connections is assumed to be 50 diameters. When performing work, it is worth remembering the most common mistakes:

binding at right angles;
lack of connection between external and internal elements;
The longitudinal rods are connected by a viscous crosshair.

You should not repeat these mistakes when building your own home.

Using a crochet hook

Before reinforcing the strip foundation, it is worth learning how to use the working tool. A special gun is rarely used for private house construction; such equipment requires additional costs. Investing in tools is only beneficial for fulfilling orders, and not when building one house.

For this reason, the most common tool for knitting in private housing construction has become a hook. It will be easier to use if you prepare special templates in advance. This part works like a workbench and makes the work much easier. Things will go faster. To make a template, wooden blocks are required, the width of which is about 30-50 cm, and the length cannot be more than 3 m, since such a workbench is inconvenient to use.

The most common way of knitting is crochet

In the wooden fixture you need to drill grooves and holes that will follow the outlines of the rods in the frame. Pieces of knitting wire 20 cm long are laid out in advance in such holes, and then the reinforcement rods are fixed.

In order to understand the knitting technology, you can consider examples. During construction, two options will be required: for crosses (when the elements are located perpendicular to each other) and for overlap connections. In a strip foundation, the second technology is often needed; when constructing a slab structure, the first will be the most relevant.

To connect the laid frame into a single whole when joining with an overlap, the hook should be used in this order:

connections are made in several places along the length of the joint, the location of the wire is designated so that it is in the recessed part of the reinforcement profile;
the wire is folded in half and placed under the junction;
use a hook to hook the loop;
the free end is brought to the instrument and placed on it with a slight bend;
begin to rotate the hook, twisting the wire;
carefully remove the instrument.

For one overlap connection, the procedure is repeated 3-5 times. Connecting the elements at one time, as is done with cross-connection, is not enough. Tying reinforcement under a strip foundation in this case will be unreliable, since fixation at one point does not prevent the elements from shifting.

Proper connection of the frame will ensure the reliability, strength and durability of the supporting part of the building.

How to knit reinforcement? This is exactly the question that arises for those who are planning to increase the reliability of foundation structures and make them more resistant to unusual loads. The characteristics of concrete, which is actively used for the manufacture of various building systems, allow it to successfully withstand compressive loads. However, this material and structures made from it are very sensitive to stretching and bending, to which they may be regularly exposed.

Methods for connecting reinforcing elements

With the help of reinforcement consisting of metal rods, a power frame is formed in the foundation, which in its geometry resembles a cage. Such a reinforcing cage, as a rule, consists of at least two horizontal layers, including both horizontal and vertical jumpers.

In order for the reinforcing frame, consisting of individual metal rods, to have the required reliability, it is necessary to correctly connect all its elements. If they are not properly secured, the entire reinforcing structure may be subject to deformation due to the weight of the concrete being poured or due to the loads acting on the entire building system.

Knitting reinforcement must also be done at the intersections of metal rods, as well as in those areas where they intersect each other along their length.

For the foundation it can be done in several ways. The choice of a specific one of these options depends on the required reliability of the reinforcement frame and the conditions for its creation.

Clamps made of polymer materials

Tying reinforcement for the foundation can be done using clamps made of plastic. This method is the most advanced and does not require special preparation of materials. It consists in the fact that reinforcing bars are manually tied with plastic clamps, connecting them in those places where they intersect. The material from which such a clamp is made is not subject to corrosion, so the knitting made with its help is very reliable.

Tying reinforcement using welding

Welding is often chosen as a method of binding reinforcement. However, you should know that only reinforcing bars that are marked with the letter “C” can be welded together. In such situations, spot welding is usually used.

It should be borne in mind that this connection method will require the use of a welding machine, as well as experience with such equipment. In addition, welded joints very poorly withstand vibration loads that occur when using compaction devices, as well as devices that remove air bubbles from concrete.

Fixing reinforcing elements with wire

Most often, knitting of reinforcing elements is done using wire. This method does not require special skills and makes it possible to achieve the required parameters for the reliability of fixation. When deciding how to tie reinforcement, this method of fixation is most often chosen.

This knitting is done very simply: the reinforcing elements are fixed with wire, which is then tightened and securely connects all parts of the structure.

To knit reinforcement with wire, use a special hook, with which you can make connections according to various patterns. Such schemes differ in the way the wire is twisted.

Technology for connecting reinforcement with wire

Before knitting reinforcement elements, it is necessary not only to watch the corresponding video, but also to properly prepare the parts to be connected. Such preparation consists of the following:

cut a piece of wire 20–30 cm long, but you can more accurately determine the required length when you knit several sections of reinforcement;
fold the cut piece in half;
wrap the resulting bundle around the joint diagonally twice;
place the bent end of such a harness onto the reinforcement bar, and also fix the other end on it;
manually, or using a crochet hook, twist the ends of the resulting wire loop.

Process mechanization

The most common way to mechanize the process of tying reinforcement is to use a special hook. It is not difficult to make such a hook with your own hands; for this you can use a piece of reinforcement, which is bent with an eye on one side (for ease of rotation), and on the other is slightly bent and sharpened. You can watch the process of making such a hook in numerous videos posted on the Internet.

How to knit foundation reinforcement using such a device? It's very simple: just place the sharpened end of the hook in the wire loop and rotate it until it is tightly twisted.

How to simplify the process

If you set a goal to further simplify the knitting of reinforcing elements, you can use a power tool for this. This problem can be solved quite simply: take a regular screwdriver and insert a bent nail into the chuck. Such a simple device will allow you not only to correctly connect the reinforcement structure, but also to provide it with the required reliability.

There are also even more convenient methods, but their implementation will require a special tool. Such, for example, as a gun for tying reinforcement. Such equipment is quite rarely available during self-construction, but having it at hand, the process can be speeded up significantly. The convenience of such a tool is difficult to overestimate, but its cost (from 35 thousand rubles) scares off many private developers who put cost savings above speed and convenience in carrying out work on tying reinforcement.

One of the stages of foundation construction is the creation of a reinforcement frame. It is this design that is responsible for the strength of the foundation under the house. In combination with concrete, it forms a reliable support for the walls.

Knitting reinforcing bars under a strip base is considered the most suitable way of fastening the metal base of an entire reinforced concrete structure. This option not only preserves the linear and spatial shape of the frame, but also makes it possible to balance the structure to take the optimal position under the influence of the created loads.

Correct knitting prevents the connected elements from moving relative to each other.

Rules for reinforcing strip foundations

For greater strength and reliability of the foundation under the house, it is necessary to follow the rules for creating a reinforcing frame:

You need to use only high-quality durable fittings.
Smooth rods should not be used for reinforcement, since in this case the adhesion of the metal and concrete mortar, and, accordingly, the strength of the entire foundation is reduced.
It is recommended to perform the longitudinal connection using the overlapping method.
The knitting of reinforcement in the corners of the frame and at its intersections must have special strength.

Methods and schemes for knitting reinforcement cages

Most often, the reinforcement frame is a three-dimensional box-shaped structure made of horizontal and vertical rods. There are several ways to create a metal skeleton:

Four lattices are created from the rods, which are connected to each other, forming the edges of a rectangular box.
Rectangles with rounded corners are made from reinforcement. Then the rectangular rings are connected on the sides using long rods.
The most durable and expensive method is considered to be creating a frame in the form of a rectangular crystal lattice. In principle, this option repeats the previous methods, but is distinguished by greater internal reinforcement.

Wire knitting patterns

Now let’s answer the question: how to properly knit reinforcement for a strip foundation? You can connect reinforcement bars using tying wire according to several schemes:

A dead knot.
Cross knot.
Double-row knot.
Tie knots of wire in the corners.
Knitted in a bun without pulling.

In any case, you will need a special knitting device for the job. You can purchase a tying gun for rebar in specialized construction stores. A simpler device is a crochet hook. As a last resort, you can use ordinary pliers. The classic version of tying reinforcement using wire involves performing the following steps:

Cut a wire about 30 cm long and fold it in half.
The wire is taken in the left hand, and the knitting device is taken in the right hand.
The wire is brought under the connection of the reinforcing bars and the hook is inserted into the wire loop.
The rods are wrapped around the wire and its ends are placed on a hook.
The knitting device is turned in a clockwise direction so that the ends of the wire are wound together.
During the knitting process, the main thing is not to overtighten the wire to avoid breaking it. According to the advice of experienced craftsmen, it is enough to make three turns of the hook.
The hook is pulled out of the loop - the connection is complete.

The entire knitting process is very labor-intensive and time-consuming, since reinforcement of strip foundations requires volumetric frames of sufficiently large dimensions.

Step-by-step instructions for laying and tying reinforcement

Knitting a reinforcement cage and putting it in place for one person is quite difficult and inconvenient. It is best to carry out the work as a team of two or three people.

The simplest and most convenient method is considered to be tying reinforcement on the ground and then laying the finished frame elements in a trench.

You need to create a metal skeleton in a certain sequence:

The reinforcement bars are being prepared. To do this, you need to cut the long rods to the desired length.
Two long rods are laid on a flat area and their ends are aligned.
Stepping back about 20 cm from the edge of the rods, one of the methods is to tie horizontal struts on both sides.
Maintaining a distance of 20 to 40 cm, tie similar spacers along the entire length. The result is one frame element.
To get the second part, you need to repeat the steps.
Next you need to fasten both parts together. To do this, two horizontal struts are tied along the edges of the structures.
Now the frame is tied along its entire length in the same way.
Pads with a height of about 5 cm are installed at the bottom of the trench. The bottom row of the frame will lie on these pads. Supports are installed on the sides of the trench to hold the mesh in the desired position.
Next, measure the unknitted corners and joints and cut off the corresponding pieces of reinforcement. These sections will be used to link the mesh collected on the ground into a single structure.
The reinforcement is knitted using the overlapping method. First, the lower turns are tied, then they move on to the vertical posts, and lastly, the upper turns are knitted.

Other methods of connecting reinforcement

Tying reinforcement is considered the most reliable way to connect reinforcement bars when creating a frame for a strip foundation. However, there are other options for mounting a metal skeleton:

Using welding equipment. Having a welding machine in your arsenal and some skills in working with it, you can quickly and easily create a frame for a foundation from metal rods. But in this case, it is worth taking into account the features of such a reinforcement connection. First, welding thins the metal, making it more brittle. Secondly, the welded frame will be reliable only if the metal and electrodes are correctly selected, and all norms and rules are followed.
Overlapping connection. This method involves not a transverse, but a longitudinal connection of the rods. In this case, individual ends of the reinforcement have an outlet of at least 15 cm for subsequent winding with wire.
Using plastic band clamps. This method can be used when building foundations for small structures. Connecting with plastic clamps makes the knitting process somewhat easier. However, it is worth remembering that such a frame is less resistant to loads, and under the influence of low temperatures the plastic may burst.
Using clamps or brackets made of plastic or steel.

The use of reinforcement in the process of tying the foundation can significantly improve its power and strength characteristics. There are several ways to knit reinforcement; we will discuss their features and how to correctly knit reinforcement for a foundation below.

Reinforcement for the foundation of a house: features of selection and calculation

Before you begin directly knitting reinforcement for the foundation, you should first select the materials to perform this process. It is the diameter of the reinforcement for the foundation that directly determines its strength and the rigidity of the frame.

Before purchasing reinforcement, you should determine its relative strength. The ratio between the area of the frame and the foundation is 100% to 0.1%, that is, the reinforcement is 0.001 part of the foundation.

Reinforcement for foundation calculation:

1. For example, it is planned to reinforce a foundation whose width is 25 cm and height 80 cm. In order to calculate the area of the reinforced area, 25 cm x 80 cm = 2000 square centimeters is enough.

2. The resulting number should be multiplied by 0.001 and the minimum cross-sectional diameter of the reinforcement in the foundation will be 2000 x 0.001 = 2 cm.

3. 30 cm of reinforcement must be used per bundle. Each connection consists of four ligaments. Therefore, to determine the amount of reinforcement, you should calculate the number of ligaments and multiply this value by 30 cm.

The use of knitting in the process of manufacturing a reinforced frame for a foundation is explained primarily by the fact that such a connection is more reliable than welding. The seams that are formed during the welding of reinforcement tend to gradually collapse, which means that such a foundation is unreliable and will become unusable after several decades.

The technological process of tying reinforcement is based on connecting reinforcement rods in such a way that they cross each other, are tightened and twisted using pliers.

It is possible to use a special gun, which greatly simplifies the knitting process. When choosing the diameter of reinforcing bars, you should proceed from the following parameters:

number of floors in the building;
massiveness of the structure;
foundation type: shallow or deep;
quality of concrete, etc.

For the manufacture of fittings, the plant uses special equipment, thanks to which the final product is of high quality and has a long service life.

In relation to the design features, the surface of the reinforcement is of two types:

corrugated;
smooth.

For the manufacture of perforated reinforcing bars, a special form is used, due to which a corrugated cross-section in the form of two ribs is formed on their surface; these bars are distinguished by the presence of a round cross-section. Such reinforcement is more durable and resistant to mechanical damage. In addition, reinforcement with a corrugated surface has higher adhesion to concrete during the process of reinforcing the foundation. For the manufacture of such rods, various types of steel are used, the most popular options of which are 35 GS and 25 GS. The strength characteristics of the material change in relation to the class of reinforcement.

In relation to the thickness of the reinforcement, it is also divided into classes, but the diameter of this material averages from 8-25 mm. The maximum length of one rod is 120 cm.

When choosing reinforcement for foundation construction, preference should be given to materials that differ:

presence of resistance to corrosion;
excellent adhesion characteristics;
presence of plasticity;
high level of strength fatigue.

The reinforcement for strip foundations is selected from class A 2. There are several options for marking this reinforcement:

A 300;
A 400;
A 800;
A 1000.

The surface of these rods has the appearance of a pigtail, corrugated. These features make it possible to improve its adhesion to concrete. In order to ensure vertical retention of the reinforcement, it is recommended to use hot-rolled type reinforcement. It is distinguished by the presence of a smooth surface.

The optimal diameter of reinforcing bars for standard one- and two-story buildings is about 1-1.5 cm. Auxiliary reinforcement should be at least 0.5-1 cm in diameter.

Please note that only corrugated reinforcement is used as the main part of the frame, and the auxiliary part must be made of smooth reinforcement.

Foundation reinforcement: main types and their features

Composite foundation reinforcement is a non-metallic material used in the process of foundation reinforcement. Among the disadvantages of this material are:

reduced elasticity qualities, compared to steel, by four times, so this reinforcement is more resistant to bending, and therefore has less possibility of rupture;
the temperature range of use is no more than 500 degrees; if the heating temperature is higher, the fittings lose their technical characteristics;
cannot be welded, although some manufacturers install steel tips at the ends of the reinforcement, allowing it to be welded together.

Despite this, composite reinforcement has a large number of advantages, among which the following should be highlighted:

high tensile strength;
8 times lighter than steel;
the low cost of the material is another advantage, since the cost of composite reinforcement is much lower than metal reinforcement;
convenience and ease of transportation, this fittings are quite light, so there are no problems with its delivery to the construction site;
since no metal is used in the manufacturing process of composite reinforcement, it is resistant to corrosion;
in addition, reinforcement based on composites is not capable of conducting electricity and has low thermal conductivity;
has a long service life;
easy to install.

Plastic reinforcement for the foundation is a fairly good option for arranging the foundation for a small building. In addition, the use of this type of fittings will significantly save both money and time resources.

Composite reinforcement, in turn, is divided into two categories:

fiberglass reinforcement for the foundation;
reinforcement based on basalt plastic.

Foundation reinforcement diagram: reinforcement of strip foundation

Before starting work, you should decide on the type of reinforcement used to tie the frame. In addition, a foundation pit must already be dug and prepared for the strip foundation. The formwork is also installed before knitting begins.

After the preparatory work, the process of installing vertical rods, which have a smooth surface, follows. The diameter of such rods is about one centimeter. The interval between them is 50-80 cm. Two belts located horizontally are knitted onto these rods. They create the main part of the frame and are the main reinforcing element.

The main purpose of this structure is to retain the overall load from the building, preventing cracking or deformation of concrete. In the process of installing a strip foundation, it is necessary to equip exactly two horizontal belts, however, depending on the load from the building, their size and thickness of each are individually selected. If the maximum width of the foundation is 40 cm, then it is better to perform double reinforcement, that is, use two rods in the lower part and two in the upper to form the belt.

With a larger foundation width, it is necessary to use three rods, one of which is located between the other two. The use of four rods is a rather uncommon option, since to form a more rigid and durable frame, it is enough to choose reinforcement with a larger diameter rather than increase the number of rods.

The height of the vertical rods should be determined based on the immediate height of the foundation itself. The connection of vertical rods with horizontal ones is made in such a way that the vertical rods do not protrude more than 10 cm. Pay special attention to the corner areas. Since they are most susceptible to stress and compression. If corner areas are incorrectly reinforced, the system will lose strength.

Therefore, the rods are never laid to each other at an angle of 90 degrees. They bend and combine into cross ribbons. Each of the rods is overlapped by 25 cm. Thus, the frame will have high strength and will not bend under the weight of concrete.

To further strengthen the corners, reinforcing mesh is used, the cross-section of the cells is 200x200 mm. They are installed at the top and bottom of the foundation, and connections to vertical sections are made every 50 cm.

Installation of the reinforcement cage should be carried out on a previously prepared concrete pad, that is, the bottom of the pit is filled with 6-8 cm of concrete. The cushion helps prevent contact of the reinforcement with the ground, which means the metal will not corrode.

How to knit reinforcement for a foundation manually

In the process of tying reinforcement, a special tool is often used, however, if it is not available, this process can be carried out manually. To knit reinforcement yourself, you will need wire about one millimeter in diameter, pliers or a special hook. It is the last device that will help twist the wire around the reinforcement itself.

It is possible to replace the wire with plastic clamps, however, in this case, it is forbidden to walk on the surface of the reinforced frame while pouring it.

Instructions for tying reinforcement using metal wire:

1. Cut a wire measuring 30 cm. Fold it in half.

2. Wrap the wire around the rods first diagonally and place it on the hook.

3. Install the free end of the wire into the hook.

4. First turn it clockwise until the connection is securely locked. There is no need to pinch the wire so that it does not accidentally break.

If you plan to assemble a frame from reinforcement for a columnar type of foundation, then it is possible to use an exclusively smooth type of reinforcement. Please note that knitting such reinforcement is much more difficult, since the wire constantly slips off. For these purposes, special equipment is used - a knitting gun.

To carry out the tying of reinforcement in a slab foundation, a strength frame is required. For these purposes, it is necessary to use steel reinforcement, the diameter of which is 1.6 cm. It is this that will allow reinforcing the tiles in both the upper and lower parts.

On the lower part of the slab, it is also recommended to use plastic compensators; they will help to evenly distribute the entire load. Please note that the rods should protrude from the frame in the form of allowances that connect the wall and the slab.

How to knit reinforcement to the foundation: methods and technology

To make a hook with which to knit the reinforcement, it is enough to use a regular unnecessary welding electrode or a nail. Any of these materials must be bent into a hook-shaped shape. A nail is more reliable; to bend it you will need to use a screwdriver.

To knit reinforcement, you will need to place the wire in a perpendicular position in two rows. Clamp it with a special device and start crocheting or using a gun-shaped knitting mechanism.

There are two options for knitting guns:

electric;
rechargeable.

The principle of their operation is to uniformly wind the wire around the reinforcement. However, the cost of this pistol is too high, so they are not used for one-time use.

The use of knitting rather than welding of reinforcement is primarily due to the fact that during welding the quality of the steel changes and it becomes more brittle. The strength characteristics of the structure deteriorate. To perform reinforcement tying, you must have:

wire - this element is the most important in this process, since the strength of the connection directly depends on the quality of the wire; for knitting it is recommended to use baked wire with a round cross-section and a diameter of about 1 mm;
in addition, you will need a hook and plastic clamps; please note that if plastic clamps are used, then such a foundation is not allowed to be left for the winter, since the plastic cracks when exposed to frost;
plastic bosses must be placed between the surface of the formwork and the reinforcement; the main function of this element is to create a protective layer that will not allow the metal to contact the soil.

If you plan to knit reinforcement on a horizontal surface with virtually no hard-to-reach places, then it is best to use a gun. Its main advantage is the speed of work. In addition, it is possible to use a store-bought crochet hook, however, it tends to rust or break over time.

A very important factor determining the quality of reinforcement tying is the same screed on each section of the frame. Thus, the structure will be more stable and will not deform under the influence of concrete and then the load from the building.

Foundation reinforcement video: