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Before building a house and deciding which foundation to create - or a pile foundation, novice builders are faced with such a thing as a grillage. Below we will consider what a grillage is and its necessity when arranging the foundations of a building.

General form monolithic construction

A grillage is a horizontally located element of the pile foundation of a structure (a kind of belt or pillow), which takes on the entire load of the building and, evenly distributing it, transfers it to the supporting columns. This is achieved by tying the piles into an integral structure. Since the grillage on the pile foundation increases the strength of the building, it is necessary to provide sufficient rigidity to all joints.

The advantage of such a base for the building lies in its durability, strength and the possibility of building on sandy and clay soils, as well as on quicksand. In addition, due to the insignificant amount of preparatory work and the concrete mortar used, such a construction of the base of the house is considered a less expensive option compared to other types of foundations.

To better understand what a grillage is, you need to know its classification according to the following types:

• at the place of arrangement;
• on the building materials used;
• by design decision.

By location:

• Shallow. This is the optimal type of construction for obtaining reliable stability. Since the sole of the belt is built directly on the ground, the entire future load from the structure will be distributed not only between the piles, but also on the entire foundation.

• Buried. In this case, a part of the structure with a sole width of 50 cm or more enters the ground. These are used for construction, on unstable soils, of buildings with several floors.

Video: grillage device for a wooden house

Metal belt for the foundation

The metal crate is made of a channel, I-beam or square profile and has high strength and rigidity. As a rule, this design is used when arranging pile-screw foundations for. The channel is installed on the heads of the supports, and fixed by means of a welding joint.

A metal belt is used mainly in a hanging version. However, recently such structures have been used very rarely, because due to the severity of the material, special lifting equipment is required, which is economically unprofitable. In addition, the metal is at risk of corrosion processes.

Types and purpose of grillages

Grill structures differ in type and purpose. When choosing the right design, many factors are taken into account.

Strip foundations with grillages

For buildings, a fairly strong and reliable support is pile foundations with a strip grillage, for which two technologies are used. One of them is used in the arrangement of foundations above the ground level, and the second - at the stage of creating a lattice structure, which takes on part of the load.

A strip foundation is the best option for arranging a foundation on slopes and areas with difficult terrain, since it does not require complex preparatory work to plan the site with the involvement of special equipment. This design is perfect for the construction of structures made of lightweight materials.

Using a strip foundation during the construction of a house, it is necessary:

• Sand cushion, the thickness of which is 200-300 mm. It is created under the concrete frame and piles to protect them from the damaging effects of ground moisture.
• Waterproofing of the lattice and supports, for which polyethylene film, roofing material or asbestos-cement pipes are used.

When arranging the foundation, it is necessary to carefully in the tape grillage, as well as its thickness and other parameters.

For fence

The grillage device for fences is necessary for the full protection of the structure, which cannot be provided by the plane of the fence. The creation of the belt is due not only to protection from external factors, but also to ensure that, for example, pets cannot get out of the site. The reasons can be any, but the execution must always be of high quality, ensure the strength and durability of the structure.

In principle, the grillage under the fence practically does not differ from the belt used in the arrangement of the foundations of houses. The same design, building materials are used here and similar functions are performed.

For pile foundation

The need for a columnar foundation with a grillage is determined directly by the specific design of the building, its weight and the rigidity of the structure frame. In order for the supporting columns not to collapse, they are obligated to have a monolithic reinforced concrete, metal or even wooden belt.

In construction, several schemes of the pile foundation of buildings are used:

• Columns with a hinged belt are buried in the ground. This scheme is used in 90% of all pile foundations;
• The pillars rest on a crushed stone embankment without deepening into the ground. With this scheme, high rigidity of the base of the house is ensured, which allows you to minimize the likelihood of subsidence of the structure;
• Without grillage. This option is used for the construction of small houses.

On a note! Supports for the columnar base of the building can be combined, for example, brickwork is combined with pouring concrete mortar or a base of building rubble. In principle, the properties of the foundation do not change from this, but the process of arrangement is greatly simplified and the cost is reduced.

Pile-grillage foundations

Grill technology with bored piles

Arrangement of foundations with a grillage on bored piles is mandatory when building buildings on uneven terrain, slopes and unstable soils. These designs are the best option for the construction of both small houses and capital structures medium size. Bored foundations with a grillage have a bearing capacity higher than that of monolithic and strip foundations, and they are cheaper.

Bored piles, able to carry a load of about 1500 kg. For the construction of a medium-sized structure, several dozen columns will be needed, the diameter of which can reach up to 150 cm and the length up to 40 m.

For the arrangement of the base of the building does not require major earthworks. Each pile is waterproofed with two layers of roofing felt or roofing material and fixed in a non-freezing layer of soil. Waterproofing allows you to protect concrete from destruction and reduce soil pressure on the supports.

Advantages of the base on bored supports:

The tops of the installed pillars are cut at the same level, after which they are combined with a common belt. Grillage on bored piles allows for uniform distribution of the load exerted by the weight of the structure over the entire base of the building. The device of the pile-grillage foundation can be seen in the video below:

The disadvantage of this design is the fact that due to the presence of free space between the floor and the ground, the bored foundation with the grillage needs to be insulated. This leads to additional labor and material costs.

Grill on screw piles

The advantage of foundations on screw piles is that they do not require excavation for their installation, and they are usually used on clay and heaving soils. After the supports are installed, their heads are cut into one level and a lattice belt is made.

Monolithic reinforced concrete and concrete structures for screw piles are extremely rare, since this type of support is used to build light structures. Most often, a pile-screw grillage is made of a metal corner or channel.

Before installing the grillage on the heads, metal platforms are welded to them, the size of which should allow the axial displacement of the supports to be corrected. Further, a channel or a corner is used to tie all the piles, as a result of which a strong and reliable structure is created.

Important! Before the installation of the foundation and grillage on screw piles, it is necessary to carry out anti-corrosion treatment of all metal structural elements. This will significantly increase the life of the structure under construction.

Main dimensions and dimensions

To create a strong and durable foundation, it is necessary to make the right calculations. The shape and dimensions of the grillage used are determined by the design features of the building being erected, the loads on the foundation, the number and location of piles.

The grillage is created, as well as the design of the strip foundation. The height of grillages for pile foundations directly depends on the level to which the building should be raised from the ground, as well as on its weight. You can independently perform the calculation of the structure, based on the ground or slightly recessed. In the case of a hanging belt device, it is better to entrust the calculations to specialists, since for a non-professional they are very difficult.

• B - the minimum allowable height for the support of the belt;
• M - the weight of the structure of the structure, excluding the supports used;
• L - belt length;
• R - the strength of the soil near the surface of the earth.

Reinforcing cages for belts on a pile foundation are created, as well as for a structure on a strip foundation. It is necessary to carry out longitudinal (working), horizontally and vertically transverse reinforcement in the structure. The total cross section of the longitudinal reinforcement must be at least 0.1% of the section of the belt. To select the cross section of each rod and their even number, a rebar assortment is used.

The main manufacturers and typical series of pile grillages

For private or small buildings, you can make lattice belts yourself directly at the construction site, but when erecting industrial buildings, multi-storey buildings, etc. use factory-made designs. Among the main manufacturers of reinforced concrete grillage from 35 tons, the following companies can be distinguished:

• JSC APSK "Gulkevichsky" ;
• CJSC "OBD" ;
• CJSC "T-Beton" ;
• LSR LLC. Construction-Ural» ;
• LLC "ZKPD Tomsk House-Building Company" ;
• JSC "PZSP" .

Series	Description
Monolithic reinforced concrete grillages Series 1.411.1-1/89	For the installation of bases for prefabricated reinforced concrete columns of one- and multi-storey industrial buildings of the II 20-1/70, II 20-2/70, II 20-3/70 series.	The supports of structures of the II 20-1/70, II 20-2/70, II 20-3/70 series have a section of 400*400 and 400*600 mm. and must be embedded in the foundation by 600 mm.
Series 1.011-6	Manufactured from heavy concrete class B 12.5	Square piles 300*300 and 350*350 mm.
Series for grillage made of metal: 3.407.9-1581	For operation of the structure at a temperature: ● up to -40˚C grillage is made of carbon steel grade Vst 3, corresponding to GOST 380-71; ● below -40˚C for the grillage use low-alloy steel grade 09G2S, which complies with GOST 19281-73 and 19282-73.

The name, which denotes typical grillages for pile foundations, includes the mandatory letter indices RS and RB and serial numbers. Markings RS1 - RS5 are used on square supports, and RB - for rectangular piles.

Important! If it is necessary to order grillages from 50 tons, the manufacturer of reinforced concrete products must be chosen very carefully to guarantee the strength and durability of the entire structure.

Basic provisions for the device and calculation of the pile grillage

When constructing a pile-grillage foundation, it is necessary to know the basic requirements for the grillage and carry out competent calculations of the entire structure. It is also mandatory to have an executive scheme for grillages, on which all the main structural elements are indicated. An important point when designing the foundation of a building, it is an accurate calculation of the required number of supports for each specific type of structure. The calculation is based on the total weight of the structure and the bearing capacity of the soil. The mass of the house must be divided by the bearing capacity of the soil and, we get the value of the area of ​​the designed base. To determine the margin of safety, the foundation area should be increased by 30%. To calculate the required number of support columns, the base area is divided by the volume of each pile, while the following conditions must be met:

• supports must be installed in all corners of the structure under construction;
• piles are mounted at the intersection points of the walls of the building;
• according to SNIP, the distance between the piles in the grillage is 2-2.5 m.

The connection of the pile with the belt can be rigid or loose. In the case of a free connection, the heads of the supports enter the grillage to a depth of 50-100 mm. This type of fastening is suitable for centrally loaded support columns.

With a rigid connection, the pile head is broken, and the reinforcement is exposed, after which it is embedded in a concrete or reinforced concrete grillage. This type of fastening is performed in cases where:

• the installation of pile foundations with grillages is carried out on unstable soils;
• horizontal loads are placed on the supports;
• combined or inclined supports are installed at the base;
• supporting columns work on pulling loads.

Calculation example

Consider an example of calculating a pile foundation with grillages for a one-story brick house with a hip roof made of metal. The building has two reinforced concrete floors 220 mm thick. The dimensions of the house in terms of plan are 6 * 9 m, the thickness of the bearing walls is 380 mm. The total floor height is 3.15 m, from floor to ceiling is 2.8 m, and the total length of the partitions inside the building is 10 m (there are no internal walls in the premises). At the site there is a hard-plastic mixture with a porosity of 0.5 and a depth of 3.1 m.

We pre-set the width of the grillage to 400 mm. and a height of 500 mm. The length of the support is 3 m, and the cross section is 50 cm. We focus on the pitch of the supporting piles - 1.5 m. To determine the total number of piles, it is necessary to divide the length of the grillage by the pitch of the supports and add 1 (if necessary, round the resulting value down to a whole numbers - 30 / 1.5 + 1≈21).

• Support area, m 2 3,14*0,52/4 = 0,196
• Perimeter, m - 2*3,14*0,5 = 3,14
• Mass grillage, kg- 0.4 m. * 0.5 m. * 30 m. * 2500 kg / m 3 \u003d 19500
• Mass of supports, kg- 21 * 3 m. * 0.196 m 2 * 2500kg / m 3 * 1.3 \u003d 40131
• Mass of the building, t- Weight of supports + grillage weight + sum from the table ≈ 224

To calculate the volume of the grillage and other parameters, it is necessary to determine the mass of the structure without foundation supports. As a result, we get M \u003d 204 tons. The width of the ambassador is M / (L * R) \u003d 204 / (30 * 75) \u003d 0.09 m. Such a belt cannot be used for construction, in this case, since overhangs brick walls should be no more than 40 mm. Therefore, we assign the width - 400 mm, and the height remains - 500 mm.

Article

In the general sense of the word. Instead, piles are driven in along the perimeter and under the future walls to a certain depth. But sometimes there is a danger that they will start to “walk” when the soil settles. How to protect yourself from this problem? In such a case, a method has long been invented that will help to avoid this disaster, and it is known as a grillage. What it is, how to do it, and how difficult such work is - these are the issues that we will deal with today. And let's start, of course, with general information.

Read in the article

Rostverk - what is it and what is it intended for

To begin with, it makes sense to understand what a grillage is, what exactly is invested in this concept. In fact, this is a special binding of driven or screwed foundation piles, which can be made of any material. But, for example, it is completely optional. In such structures, its role is taken over by the lower crown of logs.

It should be noted that the strength of a pile foundation with a grillage is several times higher than without it. Sometimes it happens that you can’t do without it at all. It is interesting that many who are engaged in construction on the site and making a grillage do not even know what it is called.

At the same time, some come up with their own names for such work, while others even rank it as the foundation or the building itself. Meanwhile, this is a separate intermediate and structurally necessary stage. And then, if you ask how the work was done, they may even be surprised: “The grillage foundation? What is it in general? I have ordinary piles. We hope that after today's review, our readers will not have such situations.

What material can be used to make a grillage for a pile foundation

The grillage can be made of various materials. It all depends on the purpose and size, as well as on the soil on which it will be located. He might be:

• metallic- various T-beams and I-beams are used;
• Wooden- it can be either logs;
• Concrete or reinforced concrete- for this, formwork is made, which is poured with mortar.

Let's analyze these types in more detail.

Production of a pile foundation with a monolithic grillage and its features

The monolithic grillage itself can be of two varieties:

• - this will connect all the piles of the foundation with a single foundation;
• - piles will be connected along the perimeter and load-bearing walls with a strip. It turns out a kind of raised familiar foundation.

The manufacture of a pile grillage with a monolithic slab type floor is more expensive than a tape one, but the structure will be much stronger and more reliable.

Important information! The reliability and quality of the finished grillage will depend on the correctness of the drafted project with the distribution of the subsequent load, the choice of the type of construction and the installation of the formwork. The same factors affect the consumption of concrete.

But with all the strength of a monolithic grillage on piles to compression, such a foundation does not tolerate the load on a fracture. Therefore, when constructing such structures on swampy, “floating” soils, it is better to choose a different material.

To pre-calculate the costs of performing such work, you can use documents such as state elementary estimated norms for construction work (GESN). The device of a monolithic grillage is clearly spelled out in them, including not only the material, but also the hours of operation of mechanized devices, if they are needed.

Related article:

If there are difficulties with reliable support on the land, choose a pile foundation structure. With the help of the materials in this article, anyone can prepare a project on their own without errors.

The device of a wooden grillage as the most convenient way to make a foundation

As already mentioned, the first crown of logs can also serve as a wooden grillage on a columnar foundation. However, if it is assembled, for example, then it is installed separately. The best form for this would be a beam, the dimensions of which are able to withstand the weight of the structure.

Important advice! The grillage from the timber must be impregnated as thoroughly as possible with a special compound that prevents rotting and protects against mold, fungus and insects. Nowadays, on the shelves of construction stores, the assortment of such goods is quite large. In extreme cases, you can use the usual drying oil. Remember that the service life of the foundation, and hence the entire structure as a whole, depends on the quality of processing.

The installation of a grillage from a bar on a columnar foundation is the easiest and. At the same time, the tree can better withstand fracture loads, and therefore such structures are the most common. Of course, if it is planned to build a two- or three-story building, it is better to use a more solid foundation, but such a grillage will be enough for a one-story house.

Metal base for buildings - in which case is such a material suitable?

A metal grillage is also not bad, but its construction is more expensive than a wooden grillage. The fact is that it is rather problematic to manually lift heavy T-beams or I-beams onto piles, which means you will have to order equipment. And this is an additional cost and time. In addition, the metal is prone to corrosion, so additional processing will be required. If it is not enough to prepare the material before coating with anti-corrosion agents, then an empty job will turn out and the entire protection will begin to peel off within two to three years.

Despite the fact that the metal itself is strong enough for both compression and fracture, many may be deterred from using it by the complexity of installation. Skills will be needed here, because a lot also depends on the quality of the seam.

Important! Welding seams require special and more careful processing. They are more susceptible to corrosion than the rest of the grillage.

Types of grillage, their purpose and the possibility of application in various situations

We have already mentioned the types of monolithic grillage in general terms. And now it's time to talk about this in more detail. Perhaps it is this information that will help the home master decide for himself the main question - where to start building the foundation.

The device of a strip foundation with a grillage - the nuances of the work

Let's start with the fact that if it is supposed, then the piles under it will be hammered or screwed into the ground in a special way. And this has its own explanation. The fact is that the pitch of piles in a strip grillage should be somewhat less than is allowed in a slab grillage.

Important information! The more often the supports of the pile foundation with a strip grillage are located, the better, but it is also not worth it to part too much. Fanaticism is useless in this case.

It must be understood that the distance between the piles will depend to a greater extent on the soil. Indeed, according to the laws of physics, the smaller the number of piles will be located under the grillage, the more pressure the structure will exert on them. Also, when pouring piles (if the bored option is chosen), it is necessary to remember about - this stage is mandatory.

Grillage for the fence - how the work on its implementation is carried out

Rostverk does not imply any difficulties in the device. It can be either monolithic or wooden or metal. The main task here is to calculate the installation of piles in such a way that one of them must be under the support, without which it cannot be built. For example, if it is decided that one section will be 3 m long, and at the same time the grillage is made of timber, it makes sense to drive piles every one and a half meters. And with two-meter sections, intermediate points of support may not be required. But this is if concrete sections are not planned, which weigh quite a lot. In this case, it is better to make a grillage under metal or monolith.

Pile bush - what is it and what grillage is needed for it

In simple terms, a bush is several piles united by one grillage. For example, you can take the same one that passes through a wetland with unstable soil. Then, in some places, the piles can “float”. There is only one thing left - to use a pile bush.

In order to bring this to life, it is not necessary to install one pile in an unstable place, as it was on the direct fence project. Here you should act a little differently. We mark in this place an isosceles triangle with sides of 0.5 m (for example) so that its center is exactly on a straight line. After that, we drive 3 piles in the corners and combine them with a grillage. Of course, work is added, but the strength of such a design will be many times higher. Thus, a columnar foundation with a grillage for a pile bush will be much more resistant to soil movement, and therefore more reliable.

Differences in pile-grillage foundations according to the type of underground supports

According to the type of piles, the following foundation technologies are distinguished:

• Bored grillage;
• Foundation on.

If you pay attention to the structure of the grillage itself, then you will not be able to find any differences. It's all about the arrangement and installation of piles for the foundation. This is what we will now focus on in more detail.

The technology of bored piles with a grillage and how to do it yourself

A bored foundation with a grillage is a more expensive, but at the same time, a more durable and stable option. If the deepening of the piles is not too large, it is quite possible to do all the work with your own hands without spending money on the salaries of professionals.

We will talk about the full step-by-step instructions a little later, but now we will briefly consider the technology of work. The deepenings themselves can be done with a garden drill, but if you need a decent depth or the soil does not allow you to do this work yourself, you will have to call the technician. The main task here is the correct and accurate marking where the piles will be located.

Reinforcement is quite simple. Several rods are lowered into the drilled well so that they stick out from above by at least half a meter. This will come in handy later when installing the grillage. No special strapping for the rods is required, but if you wish, it will not hurt. This is how the grillage is made on bored piles. Of course, many intermediate works are not mentioned, but in general terms it should be clear. It is also impossible to do without the insulation of bored foundations with a grillage, but everything has its time. We will explain all these steps in detail.

Grillage on screw piles - its pros and cons

There is an easier way than drilling wells and. If it is planned to build an ordinary one, then there is no need to make such a complex and strong foundation (although it should also have special characteristics). In this case, the pile-screw grillage will be the most acceptable. The technology is like that. Not too thick metal pipes that are used as piles have a kind of pointed small auger at the end. With its help, scrolling the pipe, and drive the pile to the required depth. If it is not too large, this can be done with a crowbar. If the ground is hard or rocky, and you need to go deep, you will have to call in special equipment.

After the piles are immersed to the required depth, they are combined with the grillage, made by any of the known methods.

Important information! It is impossible to put high buildings of 2-3 floors on a pile-screw grillage, especially if the ground is unstable.

Related article:

This technology is used to speed up the construction of not too heavy buildings, other architectural structures. In the article you will find step-by-step instructions for the construction of the structure and helpful tips specialists.

The main dimensions of grillages - how their dimensions differ

Starting this difficult topic, we can say that detailed information on the rules for calculating the height of grillage foundations, as well as other dimensions, is unlikely to be useful to an ordinary layman. The fact is that even knowing all the formulas necessary for calculations, it is unlikely that a person who is not connected with will be able to calculate everything correctly. That is why we will try to outline such a topic as the dimensions of the pile foundation grillage, as simply and in general terms as possible.

Let's try to understand how the load will be distributed after the building is fully completed. If we turn to the exact sciences, then with the correct construction of the structure, the load should be evenly distributed over the grillage, which (in turn) will scatter it on all the piles involved. But at the same time, it should be understood that if there are vertical load-bearing beams in the structure, they should be located directly above the pile. In this case, the load is distributed so that not the most powerful grillage can easily withstand it. Specialists, on the other hand, can freely calculate what dimensions are needed for a pile foundation in a section for all dimensions.

Important advice! It is quite possible to do without the help of engineers in such work, provided that a bathhouse, a solid shed or a warehouse is being built. If it is planned to build a capital house, then it is better to involve professionals.

What is the difference between a series of pile grillages: their most famous manufacturers

In principle, it is possible to purchase ready-made grillages, but here you need to study quite a lot of documentation. The fact is that there are a lot of series of grillages, and each differs from each other in strength, size, resistance to corrosion and many more parameters.

The most famous manufacturer of reinforced concrete grillages from 35 tons is Russian company LLC SK PromTekhStroy. But such large grillages are made only to order. For smaller sizes, prior arrangement is not required, they are always in stock. As for the production of reinforced concrete grillages from 50 tons, you can order similar ones at LLC DSK Rostverk, and it will cost a pretty tidy sum.

But for personal construction on the site, much smaller dimensions are required, and therefore it is worth considering a series of grillages in the Russian markets, which can be purchased in almost every city.

Series	Size, mm	Weight, t	Average cost, rub.
FL 8-24-3	2380x 800x300	1,15	3 000
FL 10-24-3	2380x1000x300	1,38	3 800
FL 12-24-3	2380x1200x300	1,63	5 005
FL 14-24-3	2380x1400x300	1,90	6 080
FL 16-24-3	2380x1600x300	2,15	7 120
FL 28-12-3	2800x1180x500	2,82	10 200
FL 32-12-3	3200x1180x500	3,23	14 050

It turns out that it is not difficult to purchase such products. But at the same time, it should be understood that in this case one cannot do without a crane, and this is another expense item. Typical grillages for pile foundations, which were presented, are not a complete range of companies involved in their manufacture. These series are given in order to understand in general terms the cost of finished products and compare costs (when planning your own production of a grillage).

Pile grillage device: basic provisions and rules

According to the requirements, a concrete grillage can also be considered, and therefore it cannot be ignored. Such a pile-grillage foundation is designed in such a way that the formwork is installed only along the side walls. The lower part of it is replaced by soil.

Important advice! If it is planned to remove the side walls of the formwork after the grillage has dried, then they should be smeared with special compounds. If it is not possible to purchase such mixtures, it is possible to use ordinary grease instead.

You can roughly calculate a pile foundation with a grillage yourself, but (as already mentioned) you should not do this if there is no such experience. Utility buildings are not subject to this ban. Compliance with and execution of the grillage according to the scheme is mandatory, even the slightest deviation from the dimensions is not allowed.

Now with regard to the distances between the piles. You can calculate it for a long time or make it as small as possible (which will be wrong), but there is another option. According to SNiP, the distance between the piles in the grillage must be at least a meter. If it is planned to build a structure without a project, for insurance, piles can be installed at a distance of 1 m from one another or slightly wider, depending on the bearing vertical beams.

Advice! Knowing the size of the walls, the roof, the material to be used in construction and the volume of the grillage from the project, it will not be difficult to calculate the load that the foundation will have to withstand. To do this, just use the calculator below.

Until recently, only four types of foundations were used for the construction of residential buildings - strip, slab, column and pile. The most common was the tape, since the depth of its laying depends on the freezing of the soil. This ensures that the structure under construction will be reliably protected. But recently, a pile-grillage foundation has become especially popular, which has a lot of positive qualities at a much lower cost.

What is a pile-grillage foundation

To understand in more detail what a pile-grillage foundation is, one should recall the design of a classic pile foundation. This is a supporting structure, represented by a certain number of piles buried in the ground. Piles are buried along the perimeter and area of ​​​​the future structure with a certain step, which is calculated based on the design load.

For tying the pile foundation, a grillage made of wooden beams is used.

The main disadvantage of the pile foundation is the poor distribution of the load between the supports. Therefore, this type of load-bearing base is used only for small log and frame buildings.

The pile-grillage foundation is a modernized version of the pile foundation. Bearing supports are combined with a wooden, concrete or reinforced concrete grillage, which is laid on piles.

Due to the rigid connection between the supports, the load exerted on the foundation is distributed more evenly. This makes it possible to use a pile foundation of a grillage type for the construction of buildings from blocks and bricks.

How does grillage work

The grillage is the upper horizontal part of the pile foundation, which combines the bearing supports into a single structure. This element of the foundation receives and evenly distributes the load from the walls of the building to the supports in the form of piles. Bearing elements, in turn, transfer the load to the ground.

The height of the pile-grillage foundation supports depends on the depth of soil freezing

In fact, the main task of the grillage is to combine piles into a single structure, which significantly improves load distribution, prevents individual piles from sinking into the ground, and reduces the risk of damage to load-bearing walls and other structural components of the structure.

According to the method of execution, the foundation grillage can be prefabricated or monolithic. The most illustrative example of a prefabricated grillage is a belt of steel beams, which are fixed together by welding. Basically, a prefabricated grillage is used for non-residential buildings designed for 15–20 years of operation.

A monolithic grillage is a more solid and durable structure, for the manufacture of which various materials are used. For example, a popular type of monolithic grillage is reinforced concrete tape. Sometimes this type of grillage is also called tape because of some similarity with the foundation of the same name.

Ground grillage should be located on a sand cushion up to 30 cm thick

Depending on the position of the structure relative to the ground, the following types of grillage can be distinguished:

• hanging - located above the ground at a distance of 10–15 cm or more;
• ground - the grillage lies on the surface of the earth without being buried in the ground;
• recessed - the lower part of the grillage is located below the ground level and rests on a sand and gravel cushion.

In the construction of residential buildings, a hanging or so-called high type of grillage is most often used. The distance between the soil and the lower plane of the grillage protects the main structure of the foundation from deformation and tearing out of especially heaving types of soil.

The presence of a void between the soil and the floor of the building allows the subfloor to be constantly ventilated, which reduces the level of humidity in the premises of the house or bath. Ground and buried grillage is used in the construction of low-rise buildings, when a stronger foundation with improved thermal insulation qualities is required.

Advantages and disadvantages

The advantages of a pile-grillage foundation include the following:

A pile-grillage foundation is recommended for arrangement not only on mobile and weakly bearing types of soil, but also on soils with increased density, when preparing a pit and carrying out other earthworks for a strip or monolithic foundation is unjustified.

Among the significant shortcomings of this foundation, it can be noted that it is unlikely that it will be possible to equip a full-fledged basement in the houses being built. Even when arranging a pile foundation with a recessed grillage, a large investment will be required to get a warm and functional room.

When arranging the foundation, special equipment is necessarily used, which allows you to drive piles to the desired depth. This does not apply to significant shortcomings, but before the construction of the foundation, one should not only calculate its bearing capacity, but also consider a plan for the passage of equipment.

How to make a pile-grillage foundation

Before proceeding with the construction of a pile foundation with a grillage, preparatory work should be carried out. To do this, you will need to determine the type of bearing supports and calculate their minimum number. After that, it is necessary to draw up a project or plan-scheme, where it will be necessary to arrange the supports according to the dimensions of the future structure.

Which piles are better to use

Depending on the method of immersion in the ground and the main material from which the support is made, the following types of piles can be distinguished:

In industrial construction, in addition to the listed types of piles, vibro-immersed and pressed types of piles are used. Screw piles are optimal in terms of price to quality ratio. Their bearing capacity is sufficient for the construction of timber and log low-rise buildings.

By design, screw piles are divided into three types: single-blade, multi-blade, narrow-blade. Single-bladed piles are rarely used due to low performance. They are the cheapest and most affordable type of products for the construction of pile foundations.

Multi-blade screw piles are used in the construction of houses on most types of soil. They have high strength and performance qualities. Able to withstand the weight of one- and two-story buildings weighing more than 70 tons.

Screw piles allow you to equip the grillage from timber, channel, I-beam and reinforced concrete

Narrow-bladed screw piles are a specialized type of product designed for the construction of pile foundations on rocky and hard soil types. Due to the reduced diameter of the blades, the piles are easily screwed into rocky soil. At the same time, the small diameter of the blades is quite enough to hold the support.

The location of the piles in the grillage

When arranging a pile-grillage foundation, there are several ways to arrange piles:

How to arrange piles on a house plan

In order to independently position the piles around the perimeter and area of ​​\u200b\u200bthe site where the foundation will be built, it is necessary to know the parameters of the building being erected. Based on this, an approximate plan is drawn up showing the base of the structure and piles on a reduced scale. To do this, you can use plain paper and a pencil.

Bearing supports must be located at the corners and at the intersection with the walls. If the distance between the supports exceeds 3 m, then in this area it is necessary to provide for the installation of an intermediate pile. The optimal distance between intermediate piles is 2–3 m. After the location of the piles, you can proceed to their selection, taking into account the method of penetration and material.

When drawing up a diagram, the dimensions and distance between the piles must be indicated

The exact number of piles and their bearing area depends on the design mass of the building being erected. The bearing capacity of piles of a certain type must be specified in the product specification, which can be found on the manufacturer's website or at the point of sale where the piles will be purchased.

Based on the distance between the piles and their bearing capacity, the minimum required number of products is calculated.

Calculation of pile-grillage foundation

As an example, we calculate the number of screw piles required to build a frame house with a size of 8 × 8 m. The total weight of the building will be 30 tons. The structure will be erected on medium density soil.

The step between piles should not exceed 3 m

The calculation of piles for the foundation is carried out in the following sequence:

The total load on the foundation is 30000 + 9600 + 11520 = 51120 kg. Taking into account the reliability factor: 51120 * 1.1 = 56232 kg.

The number of piles is 56232 / 2000 = 28.116 pieces, but since the pile is a one-piece product, in our case, 29 pieces will be needed. Pile length 2500 mm. The step between the supports is 2 m.

The coefficients used in the formulas were taken from SNiP 2.01.07–85 “Loads and Impacts”.

Foundation pouring technology

After drawing up a plan and calculating the minimum number of piles required, you can purchase material and begin preparing the site for the foundation. To do this, it will be necessary to carry out marking on the selected plot of land and carry out earthworks.

Marking the place for the foundation

To mark the site for the construction of the foundation, wooden pegs and a nylon cord are used. First of all, it is necessary to carefully level the site with the help of improvised means and garden tools. If the site is highly embossed, then special equipment may be needed, with the help of which the place must be given a uniform slope.

After installing the pegs or steel rods, a nylon thread is pulled between them

Further steps for marking the place for the foundation are as follows:

The result should be a markup showing the dimensions of the supporting foundation. This will determine the points where the piles will be screwed in or poured.

Earthworks and piling

The earthworks that need to be carried out before the construction of the foundation largely depend on the type of piles chosen. For the arrangement of a pile foundation of a grillage type intended for residential buildings, screw or bored piles are most often used.

Screw piles are screwed into the ground manually or using a special installation without prior preparation of the well. As a reference in height, a cord is used, which is stretched relative to the horizon.

Preparation of wells and filling of bored piles is carried out as follows:

1. With the help of special equipment, wells are drilled in the ground to a depth of 80–100 cm. The diameter of the well depends on the total weight of the structure and the cross section of the nozzle used. If necessary, the well can be expanded with a conventional shovel.

   Before pouring the concrete mix, a reinforcing frame is installed in the well

2. The inner walls of each well are cased insulating material. For example, you can use a regular roofing material. To do this, it is necessary to cut a sheet of roofing material 50–70 long and carefully insert it into the well.
3. After isolation, a 5 cm layer of gravel with a fraction of 20–40 is poured onto the bottom of the well, which is lightly compacted with a wooden lath. Further, a reinforcing frame made of steel reinforcement Ø18–22 mm is installed in the well.

   Concrete grade M500 is used for pouring bored piles

4. The standard version of the frame consists of 4 rods connected by crossbars made of reinforcement Ø 14–16 mm in increments of 20 cm. An approximate knitting pattern is shown in the photo above. The upper part of the frame must necessarily go out of the well by 15–20 cm. This is necessary for its further connection with the grillage.
5. After all the preparatory steps, the concrete mixture is poured. To do this, use concrete brand M500 from the manufacturer. If you plan to mix the mortar yourself, it is recommended to use a concrete mixer and ready-made dry mixes.

If opportunities and skills allow, then the knitting of the frame can be done by welding. Otherwise, stainless steel wire is used. When pouring piles, it is recommended to ram the concrete. This can be done with a steel reinforcement bar or a wooden slat. This will help to avoid the formation of voids in the concrete.

Grillage device and formwork installation

Welding is used to install the grillage from steel beams. In the process of work, it is necessary to weld the prefabricated structure of the grillage to the pile heads in the form of a reinforcing frame.

The reinforcing belt of the grillage must be securely attached to the pile frame.

To install a recessed reinforced concrete grillage, you will need to do the following:

Instead of a regular board for making formwork, you can use thick plywood or sheets of metal. In the manufacture of formwork, it is worth remembering that its height should be 5–10 cm above the level of the grillage.

Installing embedded parts and pouring the grillage

Before pouring the concrete mixture, it is necessary to lay pipes, which will later act as channels for various communications: heating, sewerage, water supply.

Air vents are arranged on opposite walls of the foundation or grillage

And also in the design of the grillage, vents should be provided. They are usually located on opposite sides of the foundation, which provides a natural level of traction without the installation of additional devices.

To arrange ventilation holes and further fill the grillage, you will need to do the following:

1. A short pipe is laid inside the reinforcing belt, the length of which is equal to the width of the future foundation. You can use a longer pipe, but for this you will need to cut a hole in the formwork using a drill with a crown nozzle for wood.
2. Pipes are laid with a certain step on opposite walls of the future grillage. If the foundation provides for internal partitions, then pipes are also installed in them. An example diagram can be found in the photo above.

   The ventilation pipe is laid between the bars of the reinforcing cage

3. After laying the pipes, you can proceed to the preparation of a concrete mixture based on M500 cement. Before pouring, the protruding part of the piles and the inner surface of the formwork are insulated with roofing material.
4. The concrete mixture is poured from any corner of the formwork. During the pouring process, concrete is rammed using a special tool or improvised means. It is important that the full pouring of the grillage be completed in one work shift. The top layer of concrete is leveled using a rule and checked for level.

   Full hardening of concrete will occur in 25-28 days from the moment of pouring

5. After pouring, the structure is closed with a plastic film. If the grillage was poured at a temperature above 20 ° C, then after 4–5 days the formwork can be removed, and after 7–10 days, further construction work can begin.

If the work on the arrangement of the pile-grillage foundation was carried out at a temperature below 10–15 ° C, then the formwork can be removed only after 14–16 days.

Video: do-it-yourself pile-grillage foundation

The pile-grillage foundation is the most successful design of the bearing foundation, which combines the high performance qualities of the strip and pile foundation. This type of foundation is perfect for the construction of residential buildings on frame technology, and for the construction of baths, saunas or buildings for technical purposes.

Domestic builders of private houses usually prefer to make a foundation in a monolithic tape design. But with large values ​​​​of the depth of soil freezing, this option is expensive. After all, in such a situation it has to be laid very deeply, and these are additional significant costs for reinforced concrete. In order to reduce the estimate for the construction of the foundation of the cottage, now private developers have increasingly begun to give preference to a pile grillage foundation, the deepening of the supporting piles of which is much cheaper.

What is a pile foundation with a grillage?

Structurally, a pile-grillage foundation is a series of supports immersed in the ground below the freezing point, and connecting them on top with a "strapping" of steel or reinforced concrete. The first rows of bricks or timber (logs) are already laid on the latter. This design provides a uniform redistribution of loads from both the house and the ground.

Foundation scheme

The point impacts arising from heaving from the piles diverge along the entire grillage tape of such a base. Walls do not experience excess pressure at any one point. Distortions and destruction of masonry on a similar basis are practically excluded.

Types of foundation on piles

The grillage of this type of pile foundation is made of monolithic reinforced concrete or a steel channel. The most commonly used concrete structure with reinforcement. It can withstand significant loads. The option, where the strapping is metal, is more intended for light buildings (garages, outbuildings, buildings from SIP panels and baths).

Pile foundation with metal framing

Pile foundation with monolithic piping

According to the type of supports used, the pile-grillage foundation can be of two varieties:

Screw.

Boronabivnaya.

In the first case, this is an almost complete copy of the foundation on screw piles. Only on the supports he has a more powerful monolithic grillage. At the same time, steel “screws” for such a design have to be chosen stronger, in which the wall thickness and diameter are larger.

Those who are going to make the foundation with their own hands often prefer to use bored piles in fixed formwork in the form of asbestos-cement pipes. This technology is simpler and cheaper when performed independently.

Advantages and disadvantages

The piles of the considered supporting structure, due to the large immersion depth, provide excellent stability to the entire mini-strip foundation from above. And they cost much less than a reinforced concrete monolith of the same height. Moreover, if the supporting pillars are connected from above not with a concrete tape, but with a metal grillage, then you can save a little more. This option is one of the most inexpensive ways to create a support for a private house.

This foundation has the following advantages:

The possibility of arranging on slopes and in swampy areas;

Comparative cheapness of the construction of a pile grillage structure;

Minimum time spent on the construction of the foundation;

No need to attract lifting vehicles;

Simplicity of technology for installing bored and screw supports, as well as pouring concrete;

Excellent stability performance in moving heaving areas.

In terms of the speed of the device, a pile foundation with a grillage is inferior only to an analogue of only screw supports. Plus, the foundation of the foundation blocks of the wall will be ready to give odds to the design in question. In both cases, the high speed of work is due to the lack of concrete work, when it is necessary to wait several weeks before the completion of concrete curing.

If the building site has a slope, then pouring a monolith on it is problematic and expensive. It will be difficult to do without this type of foundation on such a site. Only with the help of piles will it be possible to make a stable and even horizontal base for the structure. This is one of the main advantages of the foundation. All other options for him on construction sites with difficult terrain lose immediately.

Another indisputable plus is the extreme simplicity of execution. It is not difficult to make your own stuffed supports from asbestos-cement pipes and concrete inside. It is even easier to make a reinforced concrete tape, small in size and weight, on them.

Small difficulties here can arise only when mounting the formwork on weight. You can't bury it in the ground. The pillars must raise the grillage part above the ground by at least 30 cm, otherwise, with strong heaving, it can “float” from the supports along with the building from above.

The foundation with a concrete grillage on piles also has disadvantages, but there are frankly few of them:

The inability to make a basement;

The cost of additional floor insulation.

The underground space of the cottage on a pile foundation with a grillage must be closed from the wind, otherwise the constant drafts under the floor will blow out all the heat from the building. To do this, you can use facade panels from various materials or make masonry from beautiful facing bricks. Plus, the floor in such a house will definitely have to be insulated. It is better to include these expenses in the general estimate of the construction of the dwelling.

Do-it-yourself step-by-step instructions for building a foundation

The calculation and preparation of a foundation project for a house, whether it be a pile-strip foundation, is best entrusted to a professional designer. If the piles are chosen incorrectly in height and thickness, then the reinforced concrete support and the building on it will not last for a long time.

Marking on the site

At the same time, it is also not worth laying the parameters “in reserve”, this will only lead to an increase in the cost of work. As such, a do-it-yourself foundation device of the type in question should not cause difficulties. Below is a brief step-by-step instruction that will quickly understand all the nuances of this process.

To make a foundation of bored piles and a monolithic grillage, you must:

The lower edge of the supports should be below the freezing point of the soil. At the same time, wells for piles are made 10–15 cm wider than the taken asbestos-cement pipes. In order for the pillars to stand more firmly in place, an expanding concrete sole is arranged in their lower part. Pits in the ground for supports in width are made just to fit its dimensions.

Waterproofing of concrete is carried out with roofing felt or mastic. Even flexible shingles made of modified bitumen will do. True, it will cost more than ordinary roofing felts.

Usage

Comparing the pros and cons of the pile-grillage foundation structure, it is immediately clear that the former are much larger than the latter. Such a base is suitable for both small outbuildings and one-story private houses made of foam concrete or brick. At the same time, you can do everything yourself without any problems. Earthwork and concrete work will not have to be done so much, and the device of the structure itself is extremely simple.

For the construction of residential and industrial buildings, various types of foundations are used, but the pile-grillage structure deserves special attention. It is usually chosen in cases where sharp changes in relief, heaving and weak soil are observed on the land. This type of foundation is also well suited for buildings in areas located in the permafrost zone.

Specifications

The pile-grillage foundation is a reinforced concrete, wooden or steel base, poured with concrete, in which all elements are connected into a single structure. Its device can be either with a monolithic type of bookmark (covered with a slab), or built using a hanging grillage. The hanging foundation is characterized by an open gap between the soil surface and the grillage, it must be additionally insulated and covered with waterproofing. As for the monolithic version, it is formed from a concrete frame in which the height of the platforms is leveled with piles of different lengths.

Since during the laying of the foundation, piles are used, buried in the ground between the bearing layer and the lower level of freezing, it is difficult to distribute the load of the building between them. Therefore, often the pile-grillage foundation is made prefabricated from a channel and timber. All supports of this design are attached to the assembly using special tapes and concrete. It is worth noting that the combination of grillage and piles gives the bearing base reliability and stability.

Depending on the foundation being laid (wooden, metal, concrete or reinforced concrete), the building foundation acquires different technical characteristics. According to the requirements of SNiP, it is allowed to build structures with low and high grillage, which are located above ground level. They are usually made of metal pipes of large cross section or concrete. At the same time, it is much more difficult to make concrete grillages, since it is necessary to accurately calculate the place for pouring the tape from the soil.

The main feature of the foundation is that the grillages included in its device perfectly withstand uneven loads, providing the base with a rigid interface. The grillages redistribute the load, as a result of which the already “leveled” weight of the building is transferred to the piles, and the building is protected from the formation of cracks in the walls.

purpose

Unlike other types of foundations, the pile-grillage foundation ideally distributes the bearing loads from buildings to the ground, so choosing it, you can be sure that the new building will reliably serve for decades and will be protected not only from sudden temperature changes, but also from seismic activity. Such structures are widely used for both public and private construction. Particularly well suited for sites located on a slope with heaving permafrost soil and difficult terrain.

• for the construction of a brick house;
• in frame construction;
• for structures made of gas silicate blocks;
• on soils with high density;
• with high placement of groundwater;
• on unstable soil with quicksand.

The pile-grillage design also makes it possible to lay floors directly on the ground without additional leveling of the surface and pouring a deep tape, since piles installed at different heights compensate for all irregularities, eliminating height differences. You can use such a foundation in the construction of buildings with a weight exceeding 350 tons - it will be much more reliable and economical than a strip or tile foundation. But in this case, it will be necessary to lay in the project an increased safety factor, which should not be 1.2, as usual, but 1.4.

Advantages and disadvantages

The pile-grillage foundation is a single system consisting of a grillage and supports.

Due to the presence in the structure of a concrete base reinforced with reinforced elements, the base acts as a reliable support for buildings and is characterized by some advantages.

• High economic benefit. Installation does not require large financial costs, as earthworks are minimized.
• Sustainability. The large bearing capacity makes it possible to erect multi-storey buildings using heavy building materials in their decoration.
• Expanded construction coverage. Compared to other types of foundations, territory development can be carried out on any type of soil that is not suitable for laying traditional foundations. Difficult landscape geometry, slopes and slopes are not an obstacle to work.
• The possibility of forming stuffed piles separately from the grillage. Thanks to this nuance, the concrete mixture is significantly saved. In addition, you can use both ready-made and self-prepared solution.

• Convenient location of piles with cable lines and underground pipelines. This simplifies the creation of the project and does not break the functionality of the settings.
• High strength. A monolithic bundle of grillage and supports protects the structure from soil shrinkage, so the structure does not break or deform during operation.
• Lack of preparatory work. To lay a pile-grillage foundation, there is no need to form a foundation pit, which simplifies the construction process.
• Good thermal insulation. The space between the ground and the foundation, due to the increased arrangement of the grillage, does not allow cold air currents to pass through - this reduces heat losses and makes the building warm.
• No risk of flooding. Pile structures elevated above the ground up to two meters protect the building from possible flooding.
• Ease of installation. Possessing minimal building skills, it is quite possible to erect such a foundation with your own hands, without resorting to the help of craftsmen and without using earthmoving devices.
• Small terms of work.

The above advantages are relevant only if the installation of the base is carried out in compliance with all construction technologies, and the building is operated according to the loads calculated for it.

In addition to the advantages, this type of foundation also has disadvantages:

• The impossibility of building on rocky soil - hard mineral rocks make it impossible to install piles.
• Problematic installation in areas with horizontal displacement. It is not recommended to carry out work on soils that can subside, otherwise the stability of the supports will be violated, and the soil will fail.
• For buildings planned for construction in harsh climatic regions with low temperatures, additional measures will have to be considered for laying high-quality thermal insulation.
• Such grounds are not provided for the implementation of projects of houses with a basement and a basement.
• The complexity of calculating the bearing capacity of supports. It is difficult to calculate this indicator on your own. In the case of the slightest inaccuracies, the foundation can skew, and as a result, the geometry of the entire structure will change.

Despite the shortcomings, the pile-grillage foundation has proven itself well with builders and received only positive feedback from home owners.

Kinds

The supports that are used in the construction of a pile-grillage foundation are selected in accordance with the load of the building, the type of soil and climatic conditions. They can be made both from metal, concrete, wood, and from combined materials.

Therefore, depending on the characteristics of the piles and the method of their installation, some types of foundation are distinguished.

• Screw. It is made from hollow metal pipes with an open end. Works are carried out manually or with the help of special equipment. In order for the structure on screw supports to be strong, and the pipes to be protected from oxidation, their hollow part is poured with a solution.
• Boronabivnaya. It is formed on a land plot by pouring concrete into a previously prepared reinforced well located on driven piles. The stuffed foundation has high strength.
• Reinforced concrete. Installation is carried out using ready-made reinforced concrete supports arranged in a well.
• Zabivnaya. As a rule, such bases are chosen for the construction of large facilities. The supports are clogged with the help of special equipment, after which the concrete solution is poured.

In addition, the foundation may differ in the depth of the grillage and it happens:

• buried;
• ground;
• raised above the ground to a height of 30 to 40 cm.

A recessed grillage is usually used when installing piles intended for heavy structures made of aerated concrete or brick. In this case, additional strapping is performed with a slab, and the foundation can serve as the basement of the building. As for the construction of wooden structures, a foundation with a raised grillage is ideal for them - this allows you to save money on building material, and the raised building will protect against heaving of the soil.

Design and calculation

An important point before laying the foundation is its exact calculation. For this, a project and a plan of the future building are being created. Then a drawing of the base is drawn, and the pile laying scheme is necessarily indicated, taking into account their location at the intersections with the walls and in the corners. It is necessary to provide for the width between the piles to be at least 3 m. If the distance to their edge is more than three meters, then additional supports will be required. In addition, the area of ​​the piles should be calculated - for this, their number is first determined, the minimum height and thickness are selected.

For correct calculations, you also need to know some other indicators:

• the mass of the future building - it is necessary to calculate not only all the finishing materials, but also the approximate weight of the internal "stuffing";
• support area - using the known weight of the structure and the coefficient of reliability, the load on the supports is easily determined;
• dimensions and cross-sectional area of ​​​​piles - due to the known number of supports, their number can be multiplied by the selected area and get the desired value.

All results must be compared with the previously determined reference area. In some cases, it is necessary to reduce or increase the area of ​​\u200b\u200bthe supports, since their bearing capacity will depend on the diameter and type of soil.

Construction stages

The foundation on piles and grillage is a complex structure, but it is quite possible to make it yourself. In order for such a foundation to serve reliably, special TISE technology and step-by-step installation instructions must be used during work.

The construction of a pile-grillage foundation provides for the following works:

• calculation of the base and creation of the project;
• preparation and marking of the construction site;
• well drilling and trenching;
• formwork formation;
• reinforcement;
• pouring with concrete mortar and rigid sealing of seams.

Each of the above points is important, therefore, at each stage of construction, quality control should be checked, since the slightest mistake or inaccuracy will then negatively affect the operation of the building.

Marking

Before starting construction, carefully prepare the workplace. To do this, first of all, the site is cleared of mechanical obstacles in the form of stones, roots and trees. Then the earth is well leveled and the fertile layer is removed. After that, markings are applied indicating the location of the piles. The work is done with a cord and wooden stakes.

Markings must be installed strictly diagonally. Cords are stretched to mark the inner and outer surfaces of the walls. If an inaccuracy is made, deviations from the project will result, and the foundation may warp during operation.

In the event that small differences in height are observed on the site, marking is easy to perform. For areas with difficult terrain, the help of experienced craftsmen will be required. Particular attention should also be paid to the corners of the building - they should make an angle of 90 degrees.

trench digging

Once the boundaries of the foundation have been determined, earthworks can begin. First, a trench is dug under the grillage, then holes are drilled into which piles will later be installed. Work is usually carried out with the help of such hand tools as crowbar, shovel and drill. If financial possibilities allow, then you can order specialized equipment.

Depending on the purpose of the future building and the type of soil, the optimal width of the grillage is chosen. For household objects, 0.25 m is considered an acceptable indicator, for mobile objects - 0.5 m, and for residential buildings this figure increases to 0.8 m. As for the depth, the grillage can lie 0.7 m.

In a dug ditch, it is necessary to check the bottom and walls for evenness - a laser level will help with this. After that, a sand cushion is laid at the bottom of the trench, the sand is selected as a large fraction. After laying it, the surface is moistened with water and carefully compacted. The sand cushion cannot be less than 0.2 m. The next stage of excavation will be the preparation of holes for vertical piles: holes are drilled with a depth of 0.2-0.3 m.

Then, pipes are installed in the finished pits, which will play the role of formwork, and the bottom is covered with waterproofing material - this will protect the structure from moisture.

Installation of a grillage

An important point in construction is the installation of the grillage. Most often, a metal element is chosen for work, which is easily welded to the pile heads. In order for the structure to evenly transfer loads, it must be placed strictly horizontally. In the event that the foundation device according to the project provides for the use of a reinforced concrete low grillage, then additional filling is carried out from crushed stone of the middle fraction. Crushed stone is poured in several layers of 5 cm and compacted well.

Formwork is placed on the prepared base. The width of its tape should exceed the width of the walls, and the height is calculated in accordance with the indicators of the basement. The installation of stops and the assembly of shields in many respects resembles the technology of work for a strip foundation.

As for the reinforcement, in most cases, similar to the construction of the tape, two belts of ribbed reinforcement are made from below and from above. They are tied together with piles. The ends of the reinforcement emerging from the piles are bent: one row is tied to the upper belt, and the other to the lower one.

Reinforcement outlets should not be less than 50 mm from the diameters of the rods. For example, if you use reinforcement with a cross section of 12 mm, then it is recommended to bend it by 60 mm.

Laying embedded parts

After all the work on the manufacture of the frame is completed, it is necessary to consider the placement of communication systems. To do this, boxes and pipes are laid through which sewerage, electricity, plumbing and heating will pass. We must also not forget about laying pipes for engineering systems and ventilation. If this stage is not completed, then after construction, concrete will have to be hammered for installation work, which can violate its integrity and damage the building.

Pouring solution

The final stage in the installation of the foundation is the pouring of the concrete solution. For concreting, cement grade M300, crushed stone and sand are usually used. The mixture is prepared in a ratio of 1: 5: 3. In this case, the solution is not just poured - it is additionally vibrated. As a result, the surface is durable and uniform.

First of all, the holes for the piles are poured with concrete, and then the formwork itself. It is desirable to carry out the workflow in one go. If you concrete in stages, then irregularities and air bubbles may appear. The optimum temperature for pouring is considered to be + 20C - with this indicator, the formwork can be removed after four days. During this period of time, concrete will gain strength and become ready for subsequent construction work.

Sometimes the laying of the base is carried out at a temperature below + 10C - in this case, you will have to wait for complete drying for at least 2 weeks. In the winter season, poured concrete will need to be additionally heated and insulated.

The pile-grillage foundation must be erected correctly, adhering to all construction technologies - this will help increase its technical and operational characteristics.

If construction work is carried out by novice craftsmen, then they need to take into account some recommendations from experienced professionals.

• Installation should begin with calculations. For this, the type of soil and the depth of the grillage are determined. With insufficient depth of laying the support, the building can shrink and crack, after which it can even collapse.
• A huge role is played by the study of the soil, on which the bearing capacity of the structure depends. Rocks and stony soils have the highest rates. If the composition of the soil is incorrectly determined, this will lead to errors in the calculation of the load of the structure, as a result of which it will sink into the ground.
• There must be a good connection between the piles and the grillage, since under the influence of soil pressure an unstable structure can collapse.
• Regardless of the type of foundation, it is imperative to lay a sand cushion to the freezing depth - this is especially true for the operation of the foundation in winter. Frozen ground can expand and cause grillage ruptures.

• The grillage should not be in contact with the surface of the earth or be buried in it. It is necessary to remove a small layer of soil around the entire perimeter of the site, then install the formwork, fill in the sand and pour concrete.
• It is necessary to accurately calculate the step between the piles. This indicator is determined in accordance with the load on the foundation, the diameter and number of reinforcement.
• During the reinforcement, it is worth providing the right amount of ventilation products. All internal compartments must be connected to the exits to the street.
• A huge role in the construction of the base is played by insulation and waterproofing. They should be laid before the foundation is poured with concrete.
• The bottom of the pit or trench must be compacted and not loosened. It is impossible to allow the earth to crumble from the walls onto the base. In addition, sedimentary water must drain from the trench or pit, otherwise the bottom will get wet and unsuitable for pouring mortar. It is also unacceptable to have excessive steepness of slopes in trenches.
• Weak ground requires reinforcement with piles and good backfill.

• Sand, which is used to backfill the air cushion, must be moistened and distributed under the contour of the cushion at an angle of 45 degrees.
• The formwork must be securely fixed, as when pouring concrete, it may not withstand the load and collapse. Formwork deviation from the vertical by more than 5 mm is not allowed.
• The height of the foundation is made with a small margin of 5-7 cm from the height specified in the project.
• When reinforcing the frame, it is recommended to use rods with a total cross-sectional area of ​​at least 0.1% of the area of ​​the concrete element. In this case, it is best to choose smooth fittings that do not have traces of rust, dirt and paint.