We build a house on any soil: why the pile-grillage foundation is so popular. What is a grillage: varieties and tips for choosing What is a grillage in construction

Today we will talk about the most important "insides" of building structures. Many will ask: - What "internal organs" are you going to tell us about? Well, I won’t torment for a long time, I’ll answer right away.

One of the vital "organs" of any structure is the foundation grillage. Do you know what it is? Superficial? Okay, then get comfortable. Now we will study it in more detail and discuss in detail the pile-grillage foundation.

Features and basic concepts

A grillage is a so-called horizontal platform of a pile or column base, which distributes the weight of the structure and evenly transfers all its weight to the supports. And those, in turn, transfer the load to the ground.

In other words, its purpose is to combine piles or pillars into an integral working structure, which prevents uneven subsidence, cracking of walls, dampness, attack by various microorganisms, insects, rodents, corrosion and destruction of the premises.

Thus, a well-made grillage is a guarantee of the durability of the entire structure.

Recognized advantages of grillage

Our hero is known for the following undeniable advantages:

• security;
• universality;
• multifunctionality;
• practicality;
• reliability;
• strength;
• wear resistance;
• durability;
• efficiency of construction;
• reduction in the volume of necessary land works;
• reduction of labor costs for the installation of the device;
• low cost;
• high stability and bearing capacity;
• suitability for absolutely any site;
• the admissibility of use on almost any soil - sandstone, clay, and quicksand;
• the ability to create curvilinear objects;
• reduced consumption of concrete mortar (compared to the "ribbon");
• reduction of heat losses;
• vibration level reduction;
• a variety of raw materials intended for its creation;
• the ability to build at any time of the year, however, if the temperature is not lower than -10°C.

The design, thanks to a well-constructed grillage, will certainly please you with impeccable technical characteristics and a charming appearance!

Annoying Flaws

Rostverk is known for the following negative "moments":

• the need for accurate calculations;
• the impossibility of erection on moving soil - swelling and subsidence;
• inadmissibility of use in the construction of multi-storey buildings;
• the impossibility of building a basement;
• the need for additional insulation materials.

Attention! Before the construction of an object, invite highly qualified specialists to inspect the site, select the type of foundation, grillage for it and make accurate calculations.

Purpose

The grillage is a design that has a wide scope. Let's look at where and under what circumstances it is used.

1. The construction of the facility is carried out on soils:

2. The construction of the house is carried out on slopes or areas with ornate relief.

3. Creation of the structure is carried out using frame technology. Piles or poles will support the object from below.

4. The construction of the structure is carried out in the area where the soil freezes to a depth of more than 2 m.

5. The construction of an object with a base width of more than 2 m is in progress.

As you can see, grillage is a universal element.

To make a calculation, it is necessary to collect all the information about the territory on which the construction of the structure is planned.

For calculations, information is needed about:

• physical and geographical conditions;
• geological structure;
• hydrological conditions;
• the physical properties of the soil.

Based on this information:

• grillage parameters are determined;
• loads are calculated;
• the depth is calculated;
• the required number of supports is determined;
• the diameter of piles or pillars is calculated.

It is advisable to entrust this work to specialists, since a minimal slip in the calculations leads to disastrous consequences.

The price for the construction of a columnar and pile grillage varies, as it depends on the cost:

• services of construction companies (however, if you do construction on your own, you can save a lot);
• pillars or piles for the foundation (quantity + quality);
• materials needed for the construction of the facility.

The average price of this element, erected by a construction company, is $ 30-60 per 1 linear meter.

Classification

The durability, ergonomics and aesthetics of the structure depend on the type of grillage laid on a pile or column foundation. Therefore, his choice should not be taken very seriously.

Types of object by location

According to the location, there are three types of grillage.

1. High type of foundation. It is expedient, as it is located 15–25 cm, or even higher, from the surface of the earth. Due to this, additional floor ventilation is created, which eliminates dampness and the appearance of mold.

Also, this design allows you to get under the structure in order to check the integrity of the foundation of the dwelling and, if necessary, repair it without any problems. In addition, the void under the floor is an additional area for storing, for example, garden tools or for drying crops.

There is also a drawback: a basement cannot be made in a house with a high grillage, so the cellar must be built separately.

2.Low grillage type. Objects of this type are built at ground level. 20 cm of soil is removed from under the formwork so that the slab or beams are above the air cushion, but do not touch the soil.

Thanks to this design, there is no space under the dwelling that does not “steal” heat, which can significantly save on heat-insulating material. True, you will have to spend a little money to isolate the “pillow”, otherwise the grillage will lie on the ground, which will lead to shedding of the earth into open space.

3.Recessed base type. This option is very popular, as the room is very warm, comfortable, reliable, durable, safe. It is carried out as follows: a trench is dug, piles or poles are mounted, formwork is made and concrete is poured. This type of basis is excellent even for houses with several floors.

An object arranged at ground level is optimal, since it evenly distributes the load on the bearing plane.

Types of construction by design

Structurally, there are three types of foundation, but we will consider two.

1. Monolithic look. It is a solid slab or a closed beam. Monolithic grillage is most often used in low-rise construction.
2. Composite view. It is a "constructor", consisting of parts equipped with a fastening system. It is used mainly for the construction of industrial buildings and multi-storey buildings. For private housing construction, the prefabricated category is not suitable, since its manufacture is very time-consuming and costly.

The perfect option for private construction is a monolithic option, for example, from a channel or reinforced concrete. About him and the speech further.

Varieties of the base by material

There are four types of material.

1. Wood. It is perfect for tree houses and log cabins. Differs in reliability, durability, environmental friendliness, safety. But at the same time, treatment with fire-fighting, waterproofing and antiseptic compounds is required.
2. Reinforced concrete. It is made of steel reinforcement and concrete, which, combined, provide durability, wear resistance, strength and reliability to the entire facility.
3. Metal. He is strong and reliable. The grillage is perfect for the foundation on screw piles. But for the basis on bored supports - this is not the best option. In addition, a metal grillage requires the presence of lifting equipment (try to decompose and accurately align the I-beams).
4. Concrete. Experts are extremely negative about it, since the device works on bending, and its occurrence leads to cracking of concrete. The grillage is used exclusively for small buildings in the presence of many supports.

The best option is reinforced concrete types or welded metal (for frame houses).

We mount the grillage foundation with our own hands

To save money, you can build a grillage on a columnar foundation or pile base with your own hands. This is, in principle, not very problematic. But before moving on to the process of building an object, it is necessary to choose supports for the future structure.

What to use: poles or piles?

Both piles and poles are used in construction. The former are used to create houses intended for year-round use, and the latter are used to build small objects without a constant load, well, for example, baths, small country houses, gazebos, etc.

In general, piles are the best solution for the construction of a structure. But we will consider the installation of grillages for both the pile foundation and the column foundation.

Installation of a grillage for a pile foundation

So, how to make a grillage for a pile basis? Now let's figure it out. The perfect time of year for the construction of a grillage is the end of spring, the beginning of summer or early autumn.

Tools and materials

We are armed with the following materials and tools:

• shovels: "bayonet" and "selection";
• crowbar;
• stakes;
• rope;
• plywood;
• a set of steel screw piles;
• reinforcing cage;
• metal pipes;
• plumb;
• level or hydraulic level;
• tape measure;
• concrete mortar;
• special chemicals;
• foam boards;
• sand;
• rubble;
• rubber-bitumen mastic;
• ruberoid or its equivalent.

Work process

We perform the following manipulations:

• we clear the territory of vegetation (grass, shrubs, trees, etc.);
• we water the cleaned area with chemicals to prevent further growth of vegetation in the territory for the future house or bath;
• with the help of stakes and a rope, we mark and level the site;
• we mark the places where the supports for the future foundation will be located;
• for piles we choose soil 5-10 cm;
• we screw them in using a crowbar or a pipe that is inserted into the head of the support (in some cases it is reasonable to use a special technique);
• make sure that the piles are perpendicular to the ground;
• we check the tops of the piles for compliance with the horizon and one plane, if necessary, we cut them with a grinder;
• carry out reinforcement of piles;
• we fill the piles with concrete;
• we take a technical break;
• we expose the formwork using props and plywood or ready-made panels that already have supporting elements;
• pour sand and gravel into the formed boxes;
• we fix the foam boards along the walls of the boxes;
• we carry out reinforcement - we lay the prepared reinforcing cage;
• pour concrete;
• we produce waterproofing - we process concrete with mastic.

Attention! We carry out the pouring slowly, do not forget to pierce the solution, expelling air from the concrete solution.

Making a base when using pillars

We figured out the installation of the grillage for the pile foundation, and now let's start creating a bearing plane for the columnar basis.

Materials and tools

We stock up on the following set:

• "bayonet" and "selection";
• drill;
• pick;
• tape measure;
• stakes;
• chemicals to prevent vegetation growth;
• OSB board, plywood or edged board for the manufacture of formwork;
• reinforcing cage;
• concrete mortar;
• geotextile;
• sand;
• rubble;
• polyethylene;
• bituminous mastic.

Mounting process

We do the following work:

• we clear the area intended for the future building from vegetation;
• we water the working area with chemicals to prevent the growth of vegetation;
• we make the marking of the site - we drive in the pegs and pull the rope between them;
• digging holes for poles;
• we pour sand into the pits;
• pour a sand cushion (10–15 cm high) with water, ram it well;
• we put geotextiles on the sand;
• we fill the canvas with rubble;
• we make formwork - we form panels and boxes;
• we lower the box into the pit;
• cover the formwork system with polyethylene;
• we knit reinforcement;
• lower the frame into the post hole;
• we form pillars - pour concrete in layers;
• we process the concrete layer with a shovel or vibrator;
• we take a technical break;
• we process the surface of the pillars with bituminous mastic;
• we mount the formwork between the supports, make sand bedding, pour concrete mortar, which is reinforced with reinforcement;
• we make a technical pause so that the concrete hardens;
• We produce hydro and thermal insulation.

Attention! Do not rush, do the work slowly and confidently so that your creation will please with reliability. Remember, neglect of the technological process of creating a supporting structure entails devastating consequences.

So what can be said? Rostverk is an object that, despite its simplicity, plays a very important role in the "life" of each building. Do not be lazy, give a friendly and comfortable home or bath a future without destruction! Patience and good luck to you!

Foundation grillage: its types and do-it-yourself installation process

What is a foundation grillage? Its purpose, advantages and disadvantages. The main types and process of mounting a reliable carrier element.

What is a foundation grillage?

When creating wooden houses, special attention is paid to the surface of the foundation, on which a beam or log is laid. The requirements for these surfaces are quite strict - the salary (lower) crown must fit snugly against the foundation around the entire perimeter of the house. Slab and strip foundations fully meet this requirement, but their use significantly increases the cost of building a house. After all, it is necessary to carry out a much larger amount of land work, use more concrete and reinforcement, and they have no real advantage over columnar, piled and combined foundations. Columnar, piled and part of the combined foundations are much cheaper than strip or slab foundations, but it is impossible to lay a crown crown on them with high quality due to the lack of a flat surface. Rostverk eliminates this drawback.

What is a grillage

In construction, a grillage is called a wooden, concrete or steel jumper, which connects the disparate elements of the foundation (pillars or piles) to each other and creates a flat platform for laying the crown crown. Pillars or piles connected in a single chain create a structure that, in terms of strength and rigidity, is not inferior to a full-fledged strip foundation. The main problem that has to be overcome during the construction of the foundation is frost heaving of the soil. If the base of the foundation is located above the freezing depth of the soil, then there is a high probability that frost heaving will lift and break the concrete. Therefore, the construction of strip foundations in regions where the freezing depth exceeds 50 centimeters is unjustified, because it will have to be deepened by at least 100 centimeters. In most regions of Russia, the freezing depth exceeds 150 centimeters, so a strip foundation will cost 2–3 times more than a pile or column foundation. In this case, a pile or column foundation is created, which is connected with a concrete, wooden or steel jumper - a grillage.

Types of grillage

Rostverk is of three types:

Wooden grillage is the least expensive and labor-intensive, but also the most inefficient. It has insufficient mechanical strength, is prone to mold or rot, and is also unable to create a sufficiently rigid frame that combines all the elements of the foundation. Reinforced concrete grillage has good rigidity, is not afraid of moisture, and is also easy to manufacture, so it is installed on columnar foundations. After all, the pillars are made of bricks, cinder blocks and other materials to which reinforced concrete has high adhesion. On the foundations of screw piles, a concrete grillage is installed only if it is not possible to make it from a steel beam. Steel grillage has two advantages - high strength and rigidity, as well as speed of installation. However, its manufacture requires high qualification, because it is required to adjust all the details so that the height difference between them does not exceed half a millimeter. Otherwise, the high-quality fastening of the crown crown will be fraught with serious difficulties. Methods of fastening the grillage to the foundation and the blind beam to the grillage are described in the article on fastening the beam to different types of foundation.

What is a grillage, device and varieties - make a choice!

Grillage- the horizontal part of the pile-column foundation, connects individual piles (pillars) into a single structure. Its task is to evenly distribute and transfer the load from the walls to the piles and then to the ground, fixing the position of the piles and not allowing them to further deviate from the vertical. The grillage itself does not lie on the ground and does not press on the ground. This is its difference from the tape (tape-columnar) foundation. However, waterproofing is still needed.

Types of grillages

Prefabricated grillage

Prefabricated grillage, for example, from steel beams (channel, I-beam, etc.) is usually welded. Its disadvantage is the difficulty of mounting heavy beams on piles, the low strength of the connection of individual beams (joints are weaker than beams) and the high corrosion of unprotected metal located in a zone of high humidity (snow, moist ground air layer) and seam material. Convenient for short-lived construction (country houses, verandas, gazebos) with a planned service life of a maximum of 10-20 years.

Prefabricated grillage can simply be laid on top of waterproofed pile heads and attached to them without monolithic. In wooden houses, the role of the grillage is “entrusted” to the lower crown or lower trim.

Prefabricated-monolithic grillage

Prefabricated-monolithic grillage is more often used in industrial construction, construction of multi-storey buildings. This is a kind of "constructor" of pre-cast parts with "locks" and keyed connections, monolithic during (or after) assembly. It is expensive, assembled on site with heavy equipment, and requires high precision in piling. For private housing construction is unprofitable.

Monolithic cast grillage

A monolithic cast (hereinafter referred to as "monolithic") reinforced concrete grillage is cast in the form of a beam (tape, closed perimeter, open loop) or a monolithic slab. In any design option, the grillage connects the piles - being attached to them or including them in its thickness. The slab is usually high, the tape can be high, elevated, recessed. Monolithic grillage is the most convenient option for low-rise construction.

Types of grillages according to the position of the tape

According to the position of the tape (and the mounted formwork) relative to the surface of the earth, there are three types of grillage:

High grillage

The most rational is a high grillage, its lower plane is 10-15 cm higher than the ground level. This is necessary so that in winter the soil, even rising along the piles, does not press on the tape. Otherwise, raising the grillage, the frozen soil will begin to pull out the piles or (more likely the second) will tear the grillage from them.

Flaw this type of grillage for the Russian middle lane is an unsealed void between the ground and the lower floor. In fact, there is no insulating fixed air cushion under the floor, so it has to be additionally insulated, and the house cannot have a full-fledged basement. It is possible to provide for shields descending for the winter, like daggerboards, closing the gaps between the grillage and the ground.

For a subtropical climate area and for wooden construction, on the contrary, such ventilation of the space under the floor is very convenient, as it helps to reduce humidity in the house and cool the room in summer. This is how houses are built in Japan and China. In addition, with a high grillage tape, this is a convenient option for arranging a small recessed ventilated space under the house for short-term summer storage of inventory, toys, and harvested crops.

Due to shading and ventilation in this space, it is rather cool in summer, and the blind area, made with a slope from the house (especially going under the grillage), will reliably protect from rain and dirt. To go under the house, you can make a small arch in the grillage between two piles and dig a ladder and a trench-corridor under the house like a garage viewing hole, on the sides of which inventory is placed on the ground. Such access to the space under the house is convenient to periodically inspect the grillage and the lower ceiling, if necessary, correct their condition. In the villages, this is one of the favorite flying habitats for all living creatures such as chickens, dogs and cats, so the gap can be closed with a net.

Raised grillage

An elevated grillage is arranged so that its sole is flush with the ground. From under the formwork, 10-15 cm of soil is selected, so that the finished grillage hangs above the air cushion. This removes the gap in which the wind walks and to some extent makes the air cushion immobile.

But since access to the space under the house in this case is almost impossible, it is necessary to protect the space of the air cushion with dowels or simply sheets of slate, plastic, etc., freely installed outside the grillage and reaching the bottom of the trench, from shedding into this cavity of the earth. Otherwise, soon the grillage will be lying on the ground and winter heaving of the soil will begin to act on it.

It is also impossible to fix protective shields-dowels on the grillage - they must be independent, then the ground will be able to raise and lower them without affecting the grillage in any way.

recessed grillage

A foundation with a recessed grillage is both the most popular and the least rational. Along the perimeter of the building, directly along the projection line of its future walls, a shallow trench is excavated, from the bottom of which the pile heads are protruding. Then a gutter formwork is made, its bottom is located below ground level, but there is also an air cushion under it (you can put the gutter on the bars or pour a temporary sand cushion). Such a foundation also involves protective skewers, and gives an almost motionless air cushion under the floor, this insulates the house.

Do-it-yourself monolithic reinforced concrete grillage for pile and column foundations - how to make formwork, reinforcement and pouring concrete.

Conclusion on the grillage

The grillage formwork provides a removable bottom that forms a smooth lower surface of the beam hanging in the air. In general, there are no fundamental differences in the casting of different types of grillages, the differences are only in the laboriousness of earthworks or lifting the concrete mix into a higher formwork chute. Reinforcement and concrete pouring of the grillage formwork also does not differ much from the pouring of strip foundations.

A grillage is often called a columnar-strip foundation, since it looks like a strip foundation. This is an incorrect name, as there is a serious difference in design, purpose and properties. The tape at the strip foundation itself, with its entire surface, evenly transfers the full load to the ground, since the entire surface lies firmly on the ground. If she has poles, then they are more likely to be needed to increase the lateral working surface and do not play a special role in transferring loads to the ground.

The meaning of the grillage- only the combination of piles that work to transfer a point load to the ground, and the redistribution of the total load on them, while he himself does not transfer the load to the ground and never leans on it, since it is relatively weakly connected with the piles and during winter heaving of the soil from piles it can just be torn off.

The grillage is used for relatively light 1-3-storey buildings, and in seismic areas only for very light and at the same time strong wooden, frame and sip-panel houses.

What is a foundation grillage, its structure and varieties

The grillage is of three types: prefabricated, prefabricated-monolithic and monolithic-cast. By height, they distinguish: high, elevated and recessed. We choose the right one.

Rostverk - what is it? Monolithic grillage. Pile foundation with grillage

When erecting pile foundations, it is very often arranged, including such a structure as a grillage. What it is is known to almost all owners of suburban areas who have ever been involved in the construction of residential or commercial buildings. A grillage is called a structural element of the foundation of a house, connecting piles buried in the ground and distributing the load from the walls and floor between them.

Varieties

When erecting buildings for various purposes and structures, grillages can be used:

• Metal. This type is mainly used when steel screw piles are used as a bearing element of the foundation structure. A metal grillage is assembled most often from a channel or an I-beam.
• Wooden. This type is used in the construction of wooden block, log or frame-panel buildings. Piles in this case can be including concrete. This type of grillage device is a very simple procedure. In this case, either an ordinary thick beam or a log hewn from below is used as supports for the walls.
• Reinforced concrete. This variety is usually used in the construction of brick or block buildings. Structures of this type can be prefabricated (from beams) or monolithic.

Monolithic grillages

Before prefabricated, this type has the advantage that during its installation there is no need to use lifting equipment. It is this design that is most often erected by private traders when building houses on their own. A monolithic grillage, among other things, is very reliable and inexpensive.

Ways to pair the tape with piles

Sometimes grillage is placed on poles without any ligament. This method can only be used when no further horizontal dynamic impact on the foundation is expected. For centrally loaded piles, free coupling is sometimes used. In this case, their top is simply embedded into the body of the grillage tape to a depth of about 10 cm.

In the construction of residential buildings, the so-called "hard" connection is still used more often. At the same time, reinforcement (about 30-40 rod diameters long) is released from each pile, which is subsequently connected to the grillage frame. This connection provides maximum reliability of the design. The result is a very strong and durable pile foundation with grillage.

Pillar pouring

Piles during the construction of this type of foundation are buried in the ground to its dense stable layers and below the level of soil freezing. The distance between them is usually about 1-1.5 meters. A pit is drilled under each pile, the walls of which are laid with roofing material, which, among other things, also serves as a formwork. In each such hole in the ground, 4 rods are inserted, usually with a cross section of 12 mm, connected with clamps for stability.

Calculation of the grillage

The required section of the tape is easiest to find out using some computer program designed for this purpose. For example, GIPRO or "Raigage Constructor". For the calculation, you will need to enter data such as soil type, building weight, concrete grade, etc.

Grill device: preparatory work

After installing the pillars, not earlier than the concrete gains half its strength (a week), they start pouring the tape itself. Above the ground, a monolithic grillage should be located at a height of at least 5 cm, and on swampy or heaving soils - 15 cm. This is necessary in order to avoid earth pressure on it during spring heaving, and hence the separation of the tape from the heads of the pillars.

The bottom of the formwork for a grillage very high above the ground is made of boards. At the same time, a wooden “box” is arranged in a shape that repeats the configuration of the tape itself. The width of the grillage is usually made equal to the thickness of the walls.

If the tape is not too high above the ground, the formwork is made without a bottom. To keep liquid concrete inside it, a sand bed is made from below. As a "bottom" you can also use thick polystyrene foam or plywood mounted on bars. The upper plane of the piles before starting the installation of the tape must be waterproofed with two layers of roofing material.

Tape fill

So, how is the grillage itself arranged? What is it we have found out above. In fact, a grillage is an ordinary concrete tape reinforced with a metal bar. This design encircles the house around the perimeter. The grillage also passes under the walls inside it. It is poured in much the same way as a conventional strip foundation. The only thing is that in this case there is no need to perform labor-intensive earthworks, as well as to install a sand cushion.

After assembling the formwork, wooden blocks about 5 cm thick are installed on its bottom. An associated reinforcing cage is placed on them. The latter is made from a 12 mm rod. Such a section in the frame should have only longitudinal elements that bear the load. The transverse ones simply serve to connect the structure, so they can be thinner (about half).

Frame regulations

When constructing such a structure as a grillage on piles, it is allowed to use only reinforcement made in compliance with certain rules prescribed by SNiP. To strengthen the tape, you can only use a frame that has at least two tiers. Moreover, each of them must have at least two longitudinal rods.

The armature of the pillars is pre-bent and connected to the frame of the grillage using a knitting wire. The use of welding when assembling a reinforcing metal structure, both for the tape and for piles, is not allowed. The fact is that places connected in this way begin to rust very quickly, and this in turn leads to a decrease in the life of the foundation.

It is desirable to lay concrete in a tape in one step. In this case, you get the most durable and durable pile foundation with a grillage. During pouring, the mixture should be periodically pierced with a wooden stake or rod to remove bubbles. The edges of the formwork are pre-wetted with water. Sandy backfill, polystyrene foam or plywood from under the tape can be removed after a week.

Pickup device

In order for the floors in the house, based on the grillage on piles, to be warm, the space between the tape and the ground is usually covered with boards or some kind of sheet material. It can be, for example, plywood, basement siding, etc. At the same time, a bar is laid around the perimeter of the house. It is necessary for attaching the skin from below. From above, it is fixed directly on the base itself. The fence is not connected to the poles. Otherwise, it may crack during heaving.

Advantages and disadvantages

This is how such a structure as a grillage is arranged. What is it, you now know. Next, let's look at the advantages of a pile-grillage foundation for a house.

The advantages of this type of foundation include, first of all:

• Low cost. Such supporting structures are cheaper than even the currently most popular shallow-depth tape ones.
• Reliability. On problematic soils, the pile grillage ensures the longest possible service life of the building. It is practically not affected by the forces of spring heaving, as well as melt and rain water. The owners of the house have the opportunity to control the condition of the tape over the entire area, since it is not buried in the ground.
• Ease of installation.

The disadvantage of this type of foundation is considered basically only the impossibility of the device when it is used in the basement or basement. The disadvantages include not too high tensile strength of the concrete tape. It is impossible to erect a pile-grillage foundation on soils subject to movement.

Thus, you now know how the grillage is arranged. What it is, as well as what advantages and disadvantages such a design has, we found out in detail. Columnar foundations with a grillage - the foundations are very reliable, easy to install and at the same time inexpensive.

Rostverk - what is it? Monolithic grillage

To bundle the pillars and distribute the load from the walls, a special design is used - grillage. What is it known to most owners of suburban areas who have ever been involved in the construction of residential buildings or outbuildings. Most often, a monolithic reinforced concrete grillage is arranged for low-rise buildings.

When it comes to a columnar or pile foundation, two functionally significant elements are described - piles and grillage. Piles are designed to receive and transfer the load to the ground, but the question of what a grillage is is of interest to most private developers.

Description of grillage

A grillage is a horizontally located part of a pile or column foundation. The main purpose of this element is to evenly distribute the load from the entire building on piles by combining them into a single structure.

The grillage can be located at different levels relative to the surface of the earth, various materials are used for their manufacture, their execution may be different. Depending on this, the grillage is distinguished by the following features:

• Location.
• Manufacturing material.
• Execution type.

Types of grillage by location

Depending on the location relative to ground level, the following types of grillage are distinguished:

• High. This type is located above the ground at a distance of 25 cm and above. This allows you to create additional ventilation of the floor and prevent mold and dampness. In addition, the elevation above the ground makes it possible to inspect the condition of the foundation and repair it in a timely manner. Also, the space under the floor can be used as an additional area for storing garden tools and other tools. The disadvantage of such a grillage is the inability to equip the basement.
• Short. A grillage of this type is located on the same level with the surface of the earth. For its construction, a small layer of soil is removed to create a kind of air cushion. As a result of contact grillage and soil does not occur. The advantage of this type can be called the absence of space through which an indefinite amount of heat can escape. The disadvantage is the mandatory creation of insulation for the air cushion, otherwise the soil will crumble into open space.
• Buried. With this type of grillage, the room is comfortable due to the preservation of heat, reliability and durability. The manufacturing process involves preparing a trench, installing piles, installing formwork and pouring concrete into a finished structure.

Types of grillage depending on the type of execution

Depending on the design, the grillage can be of two types:

• Monolithic.
• Made.

In the first case, the grillage is made in the form of a solid slab or a closed beam. The main application is the construction of low-rise buildings. The second type involves the assembly of the structure from individual elements equipped with special fasteners. The process of manufacturing a prefabricated grillage is considered laborious and costly, so it is used in the construction of multi-storey buildings and industrial buildings.

Material for the manufacture of grillage

You can make a grillage from the following materials:

• Tree. Wooden grillage is great for building houses from timber and logs. The design is characterized by high strength characteristics, environmental friendliness and safety. However, the tree requires special attention and additional protection. In particular, a wooden grillage should be treated with a waterproofing compound, flame retardant and antiseptic solution.
• Reinforced concrete. Steel reinforcement in combination with high-quality concrete allows you to get a strong, reliable and durable structure that is resistant to wear. Thanks to this, the entire structure will serve flawlessly for many years. You can read in our previous articles.
• Metal. A grillage made of I-beams or channels is durable and reliable, but it has one drawback - the need to use construction equipment to lift heavy loads.
• Concrete. Such a grillage has a significant drawback - when the structure is bent, cracks may appear, which in turn cause the destruction of the grillage. And in this case it may be required. However, when erecting low-rise buildings and in the presence of a large number of supports, such a grillage may well be used.

Foundation construction from bored piles with grillage

The foundation on bored piles with a grillage can be called one of the most durable and durable. However, such a result can be achieved only if all calculations are made correctly and the construction technology is followed.

The calculation of the number of supports is carried out taking into account all the necessary factors and parameters, including the design of the house.

Preparatory work and site marking

Before starting the construction of any foundation, the site should be prepared for work. To do this, it is necessary to remove large debris, excess vegetation, stumps and tree roots. For more convenient work, the site can be leveled.

Then, markings are made on the prepared site. At the beginning, the places where the corners of the house will be located are marked, and wooden pegs or metal fittings are driven in. To determine the contour of the future foundation, a building cord is pulled between the stakes.

Excavation

Drilling holes for arranging bored supports is performed using a conventional garden drill. The depth of each well is determined depending on the level of soil freezing. In most cases, experts recommend lowering piles to a depth of 1.5-2 meters, this allows you to pass the level of freezing and the location of groundwater. complicates the process a little, since sand is required to be added to each hole with a layer of 5 cm.

Formwork installation and reinforcement

Asbestos-cement pipes are also used as supports for the bored foundation. In some cases, the installation of cardboard products is allowed, but they must be impregnated with bituminous mastic or used engine oil. The pipes are lowered into prepared wells, while the elevation of the upper edge of each support above the ground should be at least 5 centimeters. If the soil on the site is prone to seasonal heaving, then the distance from the ground to the upper edge of the pipe is increased to 10 cm. In any case, the foundation grillage on bored piles should not lie on the ground or touch it.

To increase the strength of future supports, it is necessary to install a frame of metal rods in each pipe. For a bunch of reinforcement, special clamps are used, which are located in 1 meter increments. The length of the reinforcing cage depends on the depth of the well, the main thing is that the bars rise above the level of the pipe by 15 centimeters.

Pouring concrete into formwork

For pouring bored supports, it is recommended to use a mixture of high grade cement, coarse sand and the required amount of water. The components are taken in a ratio of 1:3. The prepared mixture is poured into the pipe in small portions, periodically piercing the solution with a metal rod. This allows you to remove voids from the concrete mix that are formed during the pouring process. Pipes must be filled with concrete to the very top. We previously wrote about
.

Arrangement grillage

For the foundation on bored supports, a grillage in the form of a monolithic concrete tape is required. For its manufacture, you can build a formwork with a bottom, but here you can simplify the process a little. Due to the fact that the grillage will be located at a small distance from the ground, it is possible to install the side parts of the formwork, placing them at a distance in accordance with the width of the grillage.

A footing about 5 cm high is poured over the roofing material, after it has set, the formation of a frame from reinforcement bars begins. At this stage, it is important to connect the grillage frame with the rods of the bored supports.

In the process of pouring the grillage tape, it is also necessary to pierce the solution with a shovel or a metal rod.

Do you always need a grillage

For the strength and reliability of a pile or column foundation, it is necessary to connect free-standing supports into a single structure. In most cases, a grillage is used for this purpose, however, in some situations this element may be absent:

• With or timber, the function of the grillage is assigned to the lower crown of the main box of the house.
• When erecting frame structures, the lower trim is used as a grillage.

These situations apply to low-rise construction and the construction of small private houses. If the building will have more than two floors and a massive structure, then you need to take care of additional rigidity of the base.

A grillage is a necessary element of any columnar or pile foundation. Its presence allows you to evenly distribute the load of the structure between free-standing supports and get a solid, reliable and durable structure.

Any structure needs a reliable, high-quality, well-designed and equipped foundation. Today, the grillage foundation on piles is very popular, which has an economic benefit compared to the traditional strip foundation. A design feature is a horizontal bridge connecting the piles. Rostverk: what is it and what is its main purpose, is described in detail in the article.

It is necessary to start considering this issue with a definition: what is a foundation grillage. The internal building element is a horizontal concrete, steel or wooden bridge that connects the disparate elements of a columnar or pile foundation to each other, as a result of which a flat platform is created for the installation of an overlay crown. The grillage perceives the load from the supporting structures of the building and evenly distributes it to the supports, which transfer the load to the ground.

Such a design is not inferior to the traditional strip foundation in terms of its rigidity and strength, but the price of the grillage foundation will be much lower, which is associated with lower labor costs and labor-intensive work.

The base structure is created using frame technology, where pillars or piles are tied together to form a solid foundation. A foundation with a grillage is built on clay, peat, loess-like, loamy, heaving and silty soils. The construction of a house can be carried out in areas with ornate relief or on slopes.

Varieties of grillage and what types it has

Ergonomics, durability and aesthetics of the building depends on the type of grillage, which is laid on a columnar or pile foundation. It can be slab, tape and glass.

Depending on the location of the grillage relative to the subgrade, the following types of structures are distinguished:

• elevated;
• high;
• buried.

Jumper design can be:

• monolithic;
• prefabricated monolithic;
• national team.

Depending on the material of manufacture, grillages are distinguished:

• metal;
• wooden;
• concrete;
• reinforced concrete.

Element types and the main task of the grillage

The main purpose of the grillage is the perception of the load from the bearing elements of the building and its uniform distribution on the foundation. The most common and economically justified is the pile foundation.

Slab grillage on piles in the form of large-format reinforced concrete slabs is installed with significant dimensions of the structure along its perimeter. Such a grillage is placed on a standard cake, consisting of:

• sand and gravel cushion in the form of two layers of 10 cm each with vibration compaction;
• annular drainage located at the level of the sole of the grillage;
• concrete preparation in the form of a screed without reinforcement;
• waterproofing.

The strip foundation on piles can be monolithic or prefabricated. The first option is used for bored piles. This is due to the fact that the materials have the same linear expansion and technical characteristics. Also, in the body of the grillage, it is easier to wall up the heads with protruding reinforcement.

Prefabricated tape grillage is used in the technology of wooden construction. Wooden beams are stacked on the heads and joined into half a tree. This allows you to reduce construction costs and start building the structure the very next day after the foundation is laid.

Prefabricated tape grillage can be made in the form of reinforced concrete beams adjacent to the pile head. This design is used mainly for screw piles tied with I-beams or channels.

When constructing reinforced concrete bored piles with a grillage, a glass type of construction can be used. The grillage is represented by a patella mounted on a pole, a multiple of 15 cm high, 30 cm wide. Each glass should rest on four piles. This type of foundation is used for the installation of columns. Most often used in agricultural and industrial construction.

What is a grillage: element design

Monolithic grillage is the most successful solution for low-rise construction. The element is represented by an integral closed-type structure made of reinforced concrete or concrete. It is poured during construction, in the form of a monolithic slab or beam (tape). In the first version, the design links all the piles into a single system that covers the entire area of ​​the building. The tape grillage connects the piles in series and is installed only under the load-bearing elements of the structure.

The grillage, securely fixing to the piles and including them in its thickness, connects the base elements. A monolithic tape grillage can be elevated, high or recessed. It is arranged under adverse geological conditions of the soil. The implementation of such a grillage is characterized by high technical and operational characteristics. However, the design has increased labor intensity, high cost of work and requires the creation of dense reinforcement.

The prefabricated grillage is represented by a structure made of steel beams interconnected by welding. I-beams and beams are used as connecting elements. Also, the design can be made of wooden bars. This option is used mainly for the construction of non-capital structures and industrial buildings. The structure is mounted and fixed on the pile heads, which does not require subsequent embedding.

Useful advice! It is not advisable to use a prefabricated grillage for the construction of a private house, because this is associated with a very laborious and costly process.

The prefabricated type also has its drawbacks. First of all, the installation process is very laborious, which is associated with a significant weight of metal elements. In some places of the grillage, areas with low strength may form, which is associated with the low rigidity of the welded joints. Due to the formation of corrosion or decay of wood, the structure is short-lived, which is limited to 1020 years of operation.

An intermediate solution between the two previous options is a monolithic-prefabricated grillage. The prefabricated structure consists of prefabricated parts that are stacked on piles and connected to each other with a key connection. This is done during construction. Then the whole structure is monolithic.

The optimal location of the grillage

The most rational solution from the point of view of the integrity of the structure and the stability of its operation in the event of various deformations is the installation of a high or hanging grillage on bored piles. It is installed above the ground level at least 10 cm. If the distance is less, there will be a possibility of damage to the integrity of the grillage and its connection nodes with piles, which will lead to pulling out the latter.

The main disadvantage of this design is the lack of sealing of the space between the lower part of the grillage and the ground. Due to the fact that free access of cold air is created, the heat loss of the house increases. You can solve the problem by installing shields or additional insulation of the floor of the house.

Useful advice! It is advisable to choose this type of grillage for a subtropical climate, as well as for the construction of wooden structures.

The sole of the elevated grillage is located at the ground level, on which a gravel or sand cushion 10-15 cm thick is laid, for which a layer of soil is removed. Such a layer helps to reduce soil moisture under the building and free water filtration. In this embodiment, the formation of a blown area between the ground and the floor is excluded.

The buried strip foundation on bored piles is the most popular option, at the same time the most irrational. To create it, a shallow trench breaks out along the perimeter of the future building. Next, piles are installed in such a way that their heads protrude from the bottom of the trench. A sand cushion is being set up. After that, a gutter-formwork is performed, the bottom of which is located below ground level. Next, a concrete grillage is created.

Useful advice! Despite the fact that a windproof space is formed under the buried grillage, daggerboards can be mounted as additional insulation, which will take the load from the swelling soil during frosts.

What material is the grillage made of?

Reinforced concrete grillage is characterized by increased strength, reliability, stability, rigidity, bearing capacity and durability. This is the most common option. The structure contains reinforcement, which increases the strength characteristics of the grillage, taking on some of the loads. Reinforcement can be performed by creating a full-fledged spatial frame or laying individual rods.

Important! When forming a reinforced concrete grillage, a sufficient protective layer for the reinforcement must be provided.

The manufacture of a concrete grillage is identical to the previous version. The difference is the lack of reinforcement. The entire load is taken by the concrete structure, which covers the pile heads to a height of at least 10 cm. This option is less strong and durable. Concrete grillage is used in the construction of one-story buildings.

The manufacture of a metal grillage is carried out from profile rolled products, represented by I-beams and channels. The result is a strong and rigid structure. But due to the possible corrosion of the metal, especially in the places of welded joints, the metal grillage is short-lived. It is used for the construction of one-story buildings.

Characteristics of a pile foundation with a grillage

A pile foundation is a structure in which the load on the ground from the structure is transferred through piles, which are represented by pillars or beams partially or completely buried in the ground. For a rigid and reliable connection of the upper parts of the piles, a grillage is arranged. It is rational to use this type of foundation when erecting buildings on water-saturated weak soils, on slopes with a steep slope, in areas where the depth of soil freezing exceeds 2 m, also if the weight of the future structure exceeds 350 tons.

Related article:

Drainage system around the house: drainage device for the foundation of a residential building

Drainage device to protect the foundation of the building, the specificity of this procedure, the technology for creating a structure with your own hands.

Piles are metal, wooden or concrete pointed, long or heeled rods of round or square section. They are immersed in the ground in finished form or are made directly in the thickness of the soil. In finished form, the pile has a sharp end on one side, which, with the help of special construction equipment, is immersed in the thickness of the soil, passing through moving layers, rests on solid soil. In the manufacture of piles in the ground, wells are drilled, which are subsequently reinforced and poured with concrete.

Varieties of pile foundations with grillage

According to the method of immersion in the ground, the pile foundation can be stuffed, driven or screw. The first option is represented by concrete or reinforced concrete structures. To create them, the reinforcement is prestressed, which increases the crack resistance of the foundation. For the installation of piles in the thickness of the earth, it is necessary to drill the required number of holes of a given diameter and depth. A casing metal or concrete pipe is inserted into each of them. Reinforcement is lowered into it and the entire cavity is poured with concrete.

The design can be made with a closed or open lower end. The main advantage of this type of pile foundation is its high bearing capacity, simple technology, reduced cost of work, which is associated with minimal labor costs, and the absence of negative impact and vibration on surrounding structures.

The second option involves driving ready-made reinforced concrete piles into the ground. As special equipment, pile drivers, vibratory drivers and hydraulic pile crushing units can be used, the choice of which depends on the characteristics of the soil, the characteristics and depth of pile driving. This type of foundation is used in permafrost zones. Driving elements can be round, square or trapezoidal. To increase the reliability and bearing characteristics of the piles, they can be equipped with additional support rings.

Screw grillage foundation: what is it

Foundation with grillage on screw piles is one of the new options. The design has good performance characteristics and can be installed on any type of soil. The pile is represented by a hollow pipe, a sharp tip and one or more blades. The tip can be welded or cast.

For each type of soil, a certain type of screw piles is used. For stone areas, narrow-blade screw piles are used, which have especially strong welded tips and double blades, which ensures reliable adhesion to the ground and prevents pile distortion. For thawed and flooded soils, piles with a sharp cast tip and medium-sized blades are used, which guarantees an easy penetration of the element into the soil without loosening it.

For permafrost soils, piles with small blades are used, which contributes to the rapid introduction of the element into the soil without the risk of distortion. The tip of the pile has a special cutter made of extra strong alloy steels. Such items are very expensive.

Piles location options and their types

Piles can be hanging or in the form of racks. In the first version, the load on the surrounding soil is transferred through friction against the side walls. Such piles are characterized by a developed side surface along the entire length with many protrusions, which provides a good bearing capacity of the structure. This type is used for soils with a high level of groundwater or having a thick layer of weak soil, under which there is a stronger one, but it is still not able to hold a pile-rack.

Piles-racks transfer the load from the structure directly to the solid soil, which is located under a weak layer. The elements are characterized by a smooth surface, for which the soil does not cling. The most important criterion for this type of pile is a wide base, which takes more than 80% of the total load.

Useful advice! For multi-storey and durable buildings, it is advisable to choose TISE-pillars, which have a significant broadening in the lower part of the element, which makes it possible to exclude further settlement.

Piles in the ground can be located in one of the following ways:

• single;
• tape;
• stripes;
• in the form of a bush;
• field.

The first method is chosen for a free-standing support. Depending on the features of the relief, the pile can be installed obliquely. The tape method involves the placement of piles around the entire perimeter of the structure. For the construction of massive multi-storey structures, the installation of piles in several rows in the form of strips is used.

Bush placement involves the installation of elements under load-bearing walls and objects with a large load. This method is used for the construction of sheds and structures with a large number of columns that hold the roof. For a large building, the installation of piles in a checkerboard pattern is used.

The choice of pile location depends on the construction project. Elements should be located in the corners and at the intersection of the walls. The optimal distance between the piles in the grillage is 2–3 m.

Pros and cons of a pile-grillage foundation

When choosing a foundation for a future structure, it is necessary to study the pros and cons of a pile foundation with a grillage. This design has excellent stability and high bearing capacity. This is especially important for building houses on soils that are prone to movement. This type of foundation is often found in seismically active areas, when the foundation will remain stationary during small earthquakes.

Important! Classic piles are able to withstand loads up to several tons.

It is advisable to choose a pile-grillage foundation for the construction of structures on soils with a complex structure, especially in mountainous areas, which are characterized by a small layer of loose soil. Manufacturers produce piles of various lengths, which allows you to build a foundation on slopes, as well as create curvilinear objects. The pile-grillage foundation is an ideal basis for the construction of a building from any material.

Due to the fact that the grillage does not come into contact with the ground, the possibility of flooding the structure with groundwater, getting rodents and various insects into the house is excluded. For the construction of a pile foundation with a grillage, there is no need for preliminary cleaning and leveling of the construction site, which reduces the complexity and cost of work. You can build the foundation yourself without the involvement of powerful construction equipment, which is especially important in dense buildings or on small plots of land.

However, this design has its drawbacks. When designing this type of foundation, accurate calculations should be performed with the involvement of a specialist. Here you should take into account the length, diameter, weight, number of piles and their exact location.

Important! The pile foundation is not recommended for heavy, massive structures, even by increasing the diameter of the pile elements.

Another disadvantage is the laborious repair of the base, which will require the construction of retaining walls or the installation of additional piles. The construction of a pile foundation with a grillage eliminates the construction of a basement and requires additional insulation of the lower part of the building.

Calculation of the pile-grillage foundation

The calculation of the pile-grillage foundation is a serious and responsible undertaking. This process is best entrusted to a specialist in this field. To perform the calculation, it is necessary to collect information about the territory for construction: the geological structure and physical properties of the soil, hydrogeological and physical and geographical conditions of the area. You can get all the necessary information from the local geological exploration service by placing an order in advance.

Based on the data obtained, the parameters of the selected foundation are calculated. The load on the foundation with grillage is calculated based on the total mass of the structure. Next, the depth of the supports is calculated. Based on the bearing capacity of the foundation and the magnitude of the load, the minimum total area of ​​\u200b\u200bthe supports is determined. Next, the type, diameter and number of piles are selected, which are distributed over the area of ​​\u200b\u200bthe building, according to the chosen layout. Next, the dimensions of the grillage are determined by calculation.

Useful advice! To perform the calculation of a pile foundation with a grillage, you can use online calculators or the services of specialists from construction companies.

The calculation of the pile foundation grillage is carried out on the basis of SNiP II-B.1-62. It should be borne in mind that the width of the structure should be 10–20 cm thicker than the wall of the building, and the height should be approximately equal to the value of the width. The final step is the selection of building material.

Do-it-yourself pile-strip foundation device

Do-it-yourself construction of a grillage on a columnar or pile foundation is a feasible and feasible task. It is advisable to choose the first option for the construction of small structures without a constant load, such as country houses and gazebos. The pile foundation is the most popular solution for the construction of buildings intended for permanent operation.

It is advisable to do the installation of a pile-grillage foundation with your own hands in late spring, early summer or early autumn. The first step is to prepare the site by clearing it of debris and vegetation.

Useful advice! The territory for future construction is recommended to be treated with chemicals, which will exclude the growth of vegetation.

Next, the marking of the territory is carried out on the basis of the project, indicating the locations of the piles. If screw piles are used, they should be screwed in without first creating holes. To do this, you can use a pipe or crowbar, which must be inserted into the head of the support. For screw piles, it is more convenient to make a metal or wooden grillage. It is advisable to arrange a concrete jumper only for a future stone house, which requires a high rigidity of the base.

Important! Piles must be located strictly perpendicular to the ground.

If bored piles are arranged, it will not be possible to install them with your own hands. To create holes in the ground, it is necessary to involve special equipment. Bored piles can be made in two ways. The first option involves placing a formwork in the form of a metal pipe of the required diameter in each drilled hole. The internal space is reinforced and poured with concrete. The second option excludes the installation of formwork.

For the installation of a pile foundation with a grillage, concrete of class B7.5-B15 is used, which is the best solution for small buildings. For large buildings, concrete can be used, class up to B25. A more durable building material is not advisable to use for private housing construction. This is not economically justified, since the margin of safety of the material exceeds the load from the building. Reinforcement with a diameter of 12-16 mm of class A400 is laid in each hole.

Laying a pile foundation with a monolithic grillage

For work you will need the following tools and materials:

• bayonet and pick-up shovel;
• stakes;
• rope;
• wooden boards or chipboard sheets for formwork;
• set of steel screw piles;
• reinforcement for reinforcing piles and grillage;
• metal pipes;
• concrete mortar;
• plumb;
• level or hydraulic level;
• roulette;
• special chemicals;
• foam boards;
• sand;
• crushed stone;
• bituminous mastic.

The device of the pile foundation with a monolithic grillage is carried out according to the following algorithm:

• cleaning and leveling the base;
• drilling holes in the intended places of the required depth and size for piles;
• compacting the soil and creating a cushion of sand of medium or coarse fraction 30-50 cm thick at the bottom of the holes;
• installation of screw or bored piles according to the technology of work;
• preparation of a sand cushion for a monolithic grillage;
• formwork device;
• a reinforcement frame is lowered into the pit, consisting of at least 4 rods, the length of which is selected taking into account the height of the strapping;
• pouring concrete;
• creation of a wooden formwork for a monolithic grillage;
• after the concrete has hardened, the reinforcement cage for the grillage is assembled;
• installation of formwork for strapping;
• grillage concreting;
• removal of the formwork after the concrete has gained the required strength;
• performing waterproofing.

Useful advice! If an underground space is formed, it is better to close it with a decorative plinth or a fence.

The reinforcement of the grillage is carried out using A400 class rods, which can be connected into a frame by welding or tied with a tie wire. The second option is more time-consuming, but reliable. When laying the frame, leave a distance from the rod to the formwork of at least 3 cm - to create a protective layer of concrete, which will prevent the formation of corrosion.

Useful advice! At the corners of the building, the reinforcement bars must be tied with wire.

Creation of a monolithic foundation grillage on piles

Before installing the grillage, a layer of waterproofing should be laid on the piles. This is necessary in order to exclude the possibility of wetting the soles of the elements. Roofing material, polyethylene films or membranes can be used as a waterproofing material. If a pillow of fine gravel is provided under the sole of the grillage, which can violate the integrity of the waterproofing layer, a footing should be provided.

The next step is the installation of formwork for the foundation on concrete piles. To do this, marking is carried out in increments of 0.5-0.8 m with driving in pegs with a section of 5x5 cm around the entire perimeter of the building. Next, horizontal wooden boards are laid, in which holes for piles are pre-cut.

Vertical formwork elements are installed, which are nailed to horizontal boards. For formwork, it is recommended to use durable wooden boards or chipboard sheets. Inside, the prefabricated formwork should be covered with plastic wrap. Formwork dimensions must exceed the height of the future grillage by at least 5 cm.

Useful advice! In the case of a low grillage, fixed formwork can be used, which will subsequently become additional thermal insulation for the walls of the premises.

Reinforcement grillage: step by step instructions

The next step in the construction of the pile foundation grillage is the creation of a reinforcing cage, which subsequently must be completely sunk into concrete from all sides. To do this, it is necessary to lay wooden bars of any width on the bottom of the formwork in the transverse direction, but with the same thickness of 30-50 mm. They fit the bottom row of reinforcement bars, which must be connected to each other so as to ensure the same distance between the bars.

The upper belt of the reinforcing cage must be suspended from the transverse bars that connect the formwork racks. Then you should tie the lower and upper belts together.

For reinforcing a monolithic tape, A400 class reinforcement is usually used. The number of rods is calculated based on the ratio of the cross-sectional area of ​​the horizontal lintel to the sum of the sections of all rods, which is 1000:1. The following calculation procedure is performed:

• it is necessary to multiply the width by the height of the grillage, dividing the result by 1000;
• the resulting value must be divided by the cross-sectional area of ​​\u200b\u200bone bar.

The result obtained is the minimum number of bars required for reinforcement.

Useful advice! The distance between the rows of reinforcement should not exceed 150 mm.

Installation of additional elements and concreting grillage

Before concrete is poured into the horizontal lintel, special pipes should be laid through which engineering communications will pass, such as plumbing, heating, sewerage and communications. Ventilation holes should also be provided in the base.

Important! This stage should not be neglected, since then the integrity of the grillage will have to be violated.

To create a monolithic grillage, it is recommended to use concrete grades M300 and M500. When filling the formwork with concrete, use a vibrator that can shake the concrete to eliminate the possibility of cavities, which will increase the strength characteristics of the concrete.

Two hours after pouring the concrete, it is recommended to cover it with a film. If it is hot outside, it is periodically necessary to remove the film and moisten the concrete with water so that cracks do not form on its surface. Complete solidification of the structure will occur no earlier than in a week, which depends on the ambient temperature.

If the outside air temperature reaches 20 degrees, the formwork can be removed after 4 days, since the concrete base will gain more than half the strength. If the temperature does not rise above 10 degrees, the formwork does not need to be touched for 14 days. When the air temperature is below 10 degrees. it is necessary to provide additional heating and organize the insulation of the foundation. After the concrete has completely hardened, you can begin to create a waterproofing layer using bituminous mastic.

The device of a columnar foundation with a grillage

The foundation device for future construction is carried out according to the following algorithm:

• cleaning the territory from vegetation with subsequent treatment with chemicals;
• site marking based on the project;
• creating holes for future pillars;
• tamping the soil at the bottom of the pit;
• creation of a sand cushion with a height of at least 15 cm;
• geotextile laying;
• crushed stone backfill;
• execution of formwork for each pit;
• covering the formwork system with polyethylene;
• creating a frame for reinforcing piles;
• formation of pillars by pouring concrete into holes;
• surface treatment of pillars with bituminous mastic;
• installation of formwork between reinforced concrete pillars to create a grillage, the height of which should exceed the height of the future structure by 5-10 cm;
• sand cushion device;
• concreting grillage with reinforcement of the structure;
• creation of hydro- and thermal insulation.

The main mistakes in the construction of a pile-grillage foundation

The first mistake that can significantly affect the reliability and rigidity of the structure is the incorrect calculation of the load on the foundation of the building. Here it is very important to take into account the peculiarity of the type of soil of the area where the construction will be carried out.

The next mistake is considered to be a shallow laying depth or incorrect installation of piles. Free space may form in the soil under the piles, which will cause the base to shrink. This will undoubtedly lead to a decrease in the air gap under the grillage, which can cause the pile to break in winter. To exclude such a possibility, piles should be mounted below the depth of soil freezing.

In practice, there are cases when the project does not provide for the creation of an air gap under the grillage. This is especially dangerous in the winter period of the year, when the frozen ground expands significantly in different directions, including vertically. This will lead to the formation of excessive pressure on the lower part of the grillage, which may cause damage or breakage. To exclude this, care should be taken to organize the insulation layer in the form of expanded polystyrene plates, which will also play the role of artificial depreciation.

An equally important point is the creation of a reliable connection between the grillage and piles. If there is no reliable fixation, this can lead to horizontal displacement of the posts. As a result, they will not be affected by the design load from the structure, which can sink in this place.

The grillage foundation for a house or other building is the most popular and cost-effective option in modern construction. It is characterized by versatility, increased strength and reliability. A well-made grillage, in accordance with regulatory requirements, is the key to a durable structure.

Due to the high cost and complexity of installation on slopes, a new type of foundation has appeared - pile-grillage. Its peculiarity is that it is a combination of strip and column type foundations and it is used in the construction of buildings on slopes. For mountainous areas, this type of foundation is considered a priority, although it is quite expensive due to its design and design complexity.

What is the type of foundation

A grillage is a slab or beam that connects piles directly on the surface of the earth. This is actually the main load-bearing reinforced concrete belt, on which the load-bearing walls of the building itself are then mounted. As a rule, when designing and calculating a grillage, detailed drawings of all elements are used, because the main load falls directly on the slabs themselves.

Accordingly, in any scheme of such a design, calculations of the allowable loads for each pile separately, as well as for the base slabs, are already provided. It is also worth considering that the width of the tape base is significantly larger than the walls themselves. This is done in order to distribute the mass of the supporting structures of the building over the entire plane of the slabs and ensure good stability even with direct movements of a single support.

Where is grillage used?

1. During the construction of baths, technical buildings with a small mass of load-bearing structures;
2. During the construction of residential buildings on slopes with a large angle of inclination;
3. If it is necessary to make a garage or basement built into the depths;
4. When stratification is found during geodetic studies of the soil, especially when combining clay and sandy soil;
5. When restoring stone and concrete foundations of old buildings, if subsidence of individual corners is found. Then special supports are brought under the base, then the platform is poured and only then the supporting grillage is carried along the outer part.

The choice of piles for the future foundation

As a rule, it is relatively difficult to make a pile-grillage foundation with your own hands, but it is technically possible. To do this, the type of piles is first selected, and they are reinforced concrete, concrete, metal and even wooden.

Today, it is possible to fill a pile grillage even with ready-made piles that are driven into the soil with pneumatic hammers, but this technology is expensive and is more often used in the construction of large industrial, administrative and residential buildings.

There are also so-called injection piles with a diameter of up to 120 mm and a single reinforcing bar, but they are used exclusively to strengthen and repair existing foundations.

The location of the piles in the grillage

1. Single pile - here each pile is located under its support, and all supports are connected into a single whole by reinforcement;
2. Ribbon connection. Uniform distribution of all piles is provided and their distance is indicated in the drawing;
3. The strip arrangement of piles is used in the construction of massive and large buildings;
4. The location of the bushes. A whole bunch of piles is installed in one place and takes on increased loads;
5. Field location. This is the case when a monolithic slab is poured over the piles, and all the piles are installed in a checkerboard pattern according to the scheme with clear calculations of the length of each unit.

Construction of a pile-grillage foundation

• Determining the type of soil and its structure. Here it is desirable to obtain a geodetic section of the soil with detailed data for each soil layer. After all, piles are often driven to a depth of up to two meters;
• Preparation of a pit or trench. It is desirable to do it on flat surfaces, on slopes it does not give any effectiveness. The optimal solution is the preparation of small depressions in which a sand cushion is made;
• Formwork installation. It may or may not be done. If a private trader is ready to make a foundation with fixed formwork with his own hands, then such a foundation will have excellent waterproofing characteristics;
• Now you can carry out the process of deepening finished piles or pouring reinforcement with concrete mixture. Holes for piles are drilled with special equipment, then the outer contours are closed with roofing material. Asbestos pipes are installed inside the wells, which are additionally reinforced to increase the strength of the supporting structure. After the full installation of the piles, the procedure for pouring the piles with concrete and creating an intermediate backfill begins;
• After the piles have gained the specified strength, reinforcement of the frame is carried out along the entire horizontal perimeter. Reinforcement must be poured with concrete.

Errors in the design and installation of reinforced concrete grillage

1. The absence of a clear project with a detailed calculation of all the locations of the piles, their thickness, length, as well as a geodetic map of the territory.
2. There is no clear rigid connection between the pile columns and the bearing slab. If the soil begins to freeze in winter, then it expands. As a result, under the lower part of the insulated floor, the soil cools more slowly and a multidirectional force arises. This force tends to overturn the column, the frozen earth presses on the upper layers of the column, and the lower one takes the load on itself. As a result, the column begins to tilt, and if they are not fixed rigidly from above, then they will definitely be torn out of the grooves of the filled grillage.
3. An air cushion is not provided in the lower part of the grillage. If the bedding under the grillage is not removed, then a significant force will act on it through seasonal temperature changes. Over time, it will lead to a rupture of the supporting platforms, damage to the grillage tape. To prevent this from happening, during pouring, polystyrene foam plates are laid at the bottom of the pit, which play the role of a shock absorber and protect the soil from freezing.
4. Incorrect calculation of the allowable depth of piling. If they are not clogged deep enough, then in this place the building will give a drawdown, there will be a distortion of the supporting structure and a collapse of one corner. Over time, the slab itself collapses through excessive loads and the basement of the building. Also, through incorrect calculations or the design of the grillage design, a sharp rise of one or more piles is possible, and this inevitably entails the destruction of the ceilings with the further destruction of the building itself.
5. Incorrect calculation of the bearing capacity of the foundation. This mistake can often be found in novice designers without work experience and practice. Here the problem lies in the wrong choice of soil type, because the whole calculation is based on this. Rocks and stony soils have the greatest bearing capacity, fine-grained sandy soils have the smallest. If you make a mistake in the calculations, there is a risk that the future building will constantly sink into the ground over time, and this process will be very difficult to stop. Therefore, a full-fledged layout, length and diameter of each pile is needed here.

When it comes to such a building structure as a pile-grillage foundation, it must be understood that this is a symbiosis of two types of foundations: columnar and tape. In this case, the grillage tape rests on the pillars of the piles.

It bears the loads from the weight of the building and evenly distributes them over all the supporting pillars. The design is reliable, stable, so it is used on any type of soil.

Varieties of pile-grillage foundations

Basically, in this foundation structure, piles differ from each other. In civil and industrial construction, three types of them are used today:

1. Bored foundation with grillage. This is when wells are drilled in the ground, a reinforcing frame is installed in them, they are poured with concrete mortar.
2. Drop-in. These are prefabricated piles made of reinforced concrete. They are hammered into the ground with the help of special equipment.
3. Screw. These are steel pipes, at the end of which a drill is installed. They are simply screwed into the ground and filled with concrete.

The second technology is complicated in that it requires machinery to drive piles. Hence the high cost of the ongoing processes.

Advantages and disadvantages of the design

Considering the pros and cons of a pile-grillage foundation, it is necessary first of all to indicate the complexity of the design calculation. This is a big minus for those who are not specialists in the construction business. Therefore, a specialist should deal with the project and calculation of the pile foundation.

He can calculate not only the dimensions of the elements, but also the depth of the support pillars. The last factor is very important, because according to SNiP, foundations must be laid below the level of soil freezing. The disadvantages of the device pile-grillage foundation can also include:

• organization complexity basement or basement;
• it is recommended to pour such a foundation for a house built from lightweight materials.

As for the advantages of the foundation on piles with a grillage, first of all it is necessary to indicate a small amount of work being carried out, which affects the cost of construction. Here we will add the possibility of building on plots with a slope.

Construction rules

Consider the technology of pouring a strip pile foundation with bored piles as the most commonly used.

Site preparation and marking

The construction site is cleared of vegetation and debris. In some cases, the top layer is removed. Now the main stage is markup. The best option for setting the exact location of the piles is to invite a specialist with a laser level.

With the help of this tool, the places of supports and their exact location relative to the boundaries of the site are determined directly on the ground. Pegs are hammered into them, which are interconnected with twine or twine.

Now you need to set aside half the width of the foundation structure along the laid axis in two directions from the stretched thread. For example, if the width of the grillage is 40 cm, then from the axis it is necessary to set aside 20 cm on both sides. According to these dimensions, a trench is dug 30-40 cm deep.

pile construction

Wells are drilled at the place of installation of the pegs. Their diameter, the distance between the piles, the amount of penetration, the layout is determined by the design of the house. By the way, you can drill with a garden drill, the main thing is to choose it according to the diameter of the piles.

1. Falling asleep in wells sand 20-30 cm thick. it must be rammed.
2. Inserted inside metal frame made of steel reinforcement with a diameter of 8-16 mm. it is necessary to reinforce the supports, especially if the pile-grillage foundation is being built on heaving or weak soils. In SNiPs, it is indicated that frames with a round, square or triangular section can be used for columnar structures. It is necessary to make the frame 15-20 cm longer than the depth of the pile. These reinforcing ends will be connected to the frame of the monolithic grillage.
3. Filling in progress concrete mortar. Here, the M400 brand is used with the recipe - one volume of M400 cement, two volumes of fine sand, three volumes of crushed stone (fine or medium fraction).
4. Mandatory bayonet concrete mass to remove air from it.

If the soils at the construction site are weak, it is recommended to strengthen the walls of the wells. For example, twist the roofing material into a tube and lower it inside. Instead of roofing felt, any pipe is suitable here: metal, plastic or asbestos. The main thing is to withstand the diameter of the pile foundation.

If a monolithic grillage is installed on weight, then the pillars are poured with an exit above the ground level. For them, you will have to build the formwork of the basement, for which you can use all the same pipes. So, the pile foundation is ready.

The construction of the grillage

Since the grillage is a strip foundation, of a shallow type, it must be built according to the appropriate technology.

1. The trench is backfilled sand or gravel with a thickness of 20-30 cm. The laid layer is rammed.
2. Formwork is being installed from any flat material. By the way, it is not difficult to assemble the formwork for the strip foundation with your own hands.
3. Fits inside reinforcing frame made of reinforcement. It should be located in the body of the foundation structure, so it is recommended to place supports under it.
4. The ends are connected reinforcement of pillars with a frame in the grillage. This is done either by electric welding or with the help of a knitting wire.
5. Concrete is being poured, made according to the same recipe as the solution for piles.
6. Necessarily flooded in the formwork, the material is subjected to vibration.
7. Top design closed with burlap or polymer film. If it is hot outside, then you will have to pour water on the pile foundation with a grillage two or three times a day. The reason is the rapid drying of the mixture, which will lead to cracking.
8. In a week you can remove the formwork, load the foundation after 28 days (raise the walls, install the ceiling).

Many violate the requirements of SNiP, not maintaining the drying time of the concrete structure, believing that, for example, the foundation for a house made of aerated concrete will withstand a small load coming from an aerated concrete structure. And this is a big mistake. No one knows in what time range chemical processes take place inside the concrete mass.

How quickly concrete gains brand strength. After all, this indicator depends on many factors, which cannot be taken into account at the construction site. Therefore, the time range is set to 28 days. Here is such a not quite simple step-by-step instruction for the construction of a pile-grillage foundation with your own hands.

Combined variant

This is the technology of erecting a grillage with a slab. That is, there is no pile foundation in it. Usually this option is used in the construction of private houses, if the developer decides to build a house with a basement or basement on weak unstable soils.

That is, a monolithic slab with a grillage is being built in place of the house. The complexity of the construction of this structure lies in the fact that it is necessary to pour concrete so that the slab and the grillage are one. Therefore, a single reinforced frame is created.

To do this, you will have to lay a metal grate in the slab, and attach vertical pieces of reinforcement to it in two or three rows at the location of the tape, which will be connected to each other in a frame cage. The distance from the edge of the grillage to the edge of the slab is determined by the installation of vertical reinforcing bars.

But there is another difficulty - the installation of formwork for the grillage. There is nothing to attach it to, especially for internal shields. After all, the edge of the grillage is located far from the bearing support. Therefore, each element of a monolithic slab with a grillage is poured separately. This technology is defined by SNiPs.

• First the floor (slab). By the way, you can carry out its thermal insulation by falling asleep on top of the expanded clay pillow. The poured concrete must gain at least 70% of the branded strength, which takes 20-21 days.
• Then mounted formwork for grillage, and concrete mortar is poured.

This type of foundation means high material costs, difficulty in manufacturing, and requirements for accurate calculations. This is especially true of the distance from the edge of the grillage to the edge of the slab. The smaller the distance, the greater the load on the edges of the slab foundation, which can cause it to collapse.

Even if it is laid under aerated concrete. But there are also advantages. For example, there is no need to dig a pit below the level of soil freezing.

Conclusion

The device of a pile foundation with a grillage, regardless of whether bored piles or screw piles are used, is based on an accurate calculation of structural elements in terms of their size, location and depth.

Warming of the pile-grillage foundation for aerated concrete, its finishing and other construction operations is the second. The main thing is the construction of the structure itself exactly according to SNiP.