If the site has weak soil (swampy, watery sand, peat bogs), and the load on the foundation is expected to be high, the most reliable foundation for a house is a pile foundation.

In addition to reliability, a pile foundation has another important advantage: undemanding to the terrain. There is no need for careful leveling of the construction site. This greatly simplifies the process of installing a pile foundation with your own hands and reduces environmental damage to the surrounding landscape.

What types of foundations are there on piles?

Based on the nature of their interaction with the ground, a distinction is made between hanging piles and rack piles. The former rest on the ground with their side surface and withstand the load due to friction; the latter are installed with support on hard rocks underlying looser layers.

a) pile rack, b) hanging pile. 1 - pile, 2 - weak soil, 3 - strong soil.

According to the method of immersion, piles are:

• driven - reinforced concrete, steel or wood, driven by impact directly into the ground or into leader holes;

• reinforced concrete shell piles. They are immersed using the vibration method, followed by excavation of soil from the cavities or without excavation, with or without filling with concrete;

• for the foundation. Wells are drilled in the ground, reinforcement is placed in them and concrete is poured;

1 - immersion of the casing string into the ground. 2 - Extracting soil from the casing. 3 - Immersion of the reinforced frame into the well. 4 - Filling the well with concrete. 5 - Removing casing pipes.

• screw pile foundation.

Features of foundations on screw piles

A screw pile is a hollow steel rod with a sharp tip and spiral blades. The diameter of the rod is 10-30 centimeters, the length is from a quarter of a meter to 2.5 meters.

If more is required, the pile is increased. The upper end of the pipe (heel) can be rectangular, round, or U-shaped. The pile is screwed into the ground like a screw, hence the name.

During manufacturing, the surface of the rod is coated with special anti-corrosion compounds.

The service life of a pile-screw foundation is over half a century (50 years - manufacturer's warranty).

Pros and cons of a pile-screw foundation

The main advantage of a screw foundation is the ability to do without excavation work and pouring concrete. This dramatically reduces work time and energy consumption:

• no need for a concrete mixer or a large amount of material - concrete itself, reinforcement, ;
• no need to wait for the foundation to gain strength;
• no heavy equipment required. For small structures, the piles can be screwed in manually.

The exception is combined pile-strip foundations. When constructing them, you cannot do without concrete (sometimes brick is used instead, but this increases the energy intensity of the work).

Under a heavy brick house you will need a concrete strip or reinforced concrete belt.

In other cases, the piping of a pile-screw foundation is made of metal beams, for light houses -.

A) The foundation option is suitable for the construction of a frame, wooden block and brick house. B) The foundation option is suitable for the construction of a frame, wooden, block and brick house. C) The foundation option is suitable for the construction of a wooden house. D) The foundation option is suitable for the construction of a frame, wooden, block and brick house.

If the grillage is metal, the only way to connect the foundation parts is welding. If you have the appropriate equipment and skills, this greatly simplifies the process of building a foundation for a house.

Concrete is also needed when constructing a screw foundation: it fills the hollow cores of the piles themselves. But the amount of material and scope of work are not comparable to the construction of reinforced concrete structures.

Note!

The construction of a pile foundation of this type is possible on all soils except rocky ones, incl. on flooded soils.

The length of the rod can be chosen so that the pile passes through the unreliable soil and is secured in a stable layer.

• screw piles are used for private development and for small-sized structures. High-rise buildings with a large mass are not built on them;
• When screwing a pile, it is impossible to control its passage through the soil. Solid inclusions contained in the ground can damage the anti-corrosion coating;
• in the absence of a reinforced concrete base, arrangement of the basement floor is problematic;
• settlement of piles is uneven, highly dependent on soil characteristics within one area;
• despite the lack of excavation and concreting, the prices for a pile-screw foundation are significant due to the cost of the piles themselves.

Calculation of foundations on screw piles

To determine the required number of piles, you need to divide the total pressure on the ground by the load-bearing capacity of the pile.

The calculation of a pile foundation is carried out in three stages:

1. The total load is determined - the total weight of the structure, including floors, internal walls, furniture, roof, people and all the contents of the house. According to SNiP 2.01.07-85 for private houses, the payload is 150 kilograms per square. The snow load should also be added here. It depends on the region (for example, in the north of the Moscow region - 240 kilograms per square). The total value is multiplied by a factor of 1.2.
2. Additional loads are taken into account - wind force, etc. Typically, the safety margin is 30% of the design figure.
3. The bearing capacity of the soil is determined either based on the results of geological research (2.02.03-85 SNiP) or according to existing tables.

Note!

Usually, under a small private house, piles are installed with a design step of 2-3 meters.

How to make a pile foundation with your own hands?

Installation of a pile-screw foundation begins with markings. The corners of the structure are marked, and a marking cord is pulled between them. The immersion points of the piles are marked with pegs in accordance with the calculated step.

The piles are immersed at the marked points. At a immersion depth of up to one and a half meters (freezing level in the middle zone), this can be done manually.

If the depth is greater or the soil in the area is very dense, special equipment is used for screwing.

• align the piles in height (tighten some, cut others);
• fill the cavities with concrete mortar;
• install grillage.

Price of foundation on screw piles

The price of a screw foundation depends on the length of the piles, cross-section, and wall thickness. The cost of a screw pile for a foundation is influenced by its design features: reinforced tip, reinforced blade.

Approximate prices:

• pile 5.7 cm (for gazebos and other lightweight structures), steel thickness 3.5 mm, length 1.5 meters - from 800 rubles, immersion - from 1.2 thousand rubles;
• pile 8.9 cm (and), thickness 3.5 mm, length 2 meters - 1.1 thousand rubles, immersion - 1.4 thousand rubles;
• pile 13.3 cm (for a private cottage), thickness 4 mm, length 3 meters - from 2 thousand rubles, immersion - from 1.8 thousand rubles.

The cost of a pile-screw foundation also includes the price of grillage materials and its installation.

The construction of any building begins with the foundation. It is very important to choose the right type, since the estimate for this type of work can reach 30% of the cost of the entire facility. In addition, everything is complicated by the fact that during operation, access to these structures is limited, and carrying out inspections or repairs becomes quite a costly undertaking. The article will discuss the construction of a pile-screw foundation.

Types of foundations

Three types of structures are most often used:

• tape;
• slab;
• pile

Pilings allow significant savings compared to others and can perform their functions on soils with poor characteristics. They, in turn, are divided into:

• bored, made from monolithic reinforced concrete directly on the construction site;
• driven, installed in the design position using a special installation;
• screw, metal piles immersed in the ground by screwing.

Driven piles were used quite often a couple of decades ago. If there was construction going on within a kilometer area, you could hear strong pops that occurred when a heavy load hit the pile. This method has limited application; for example, it cannot be used in densely built areas, since the work will have a destructive effect on neighboring buildings. They are also not suitable for a small building.

For the construction of individual houses, it is rational to use bored or screw piles. In the first case, it is necessary to install a reinforcement cage in the casing and fill everything with concrete. A screw foundation is much easier to install and in most cases cheaper.

What are screw piles

• This type is a long metal pipe with a screw at the end. The pipe has fairly thick walls. The propeller blades allow the foundation to curl into the ground and catch there. In this case, the screw prevents the structure from being pulled out of the ground and preventing the building from moving.

• When installing, the pile is turned with pressure. In this case, you can use special installations or physical force. The more often the blades are placed, the better the grip on the ground.
• The diameter of the pipes is usually in the range of 90-140 mm, the wall thickness is taken to be at least 4 mm. If there is a need to install products with a diameter of more than 140 mm, they must be made to order.

Types of screw piles

There are two varieties depending on the type of construction:

• cast tip;
• welded tip.

Piles with a cast tip

• Such piles are a one-piece structure consisting of a pipe and a screw tip. Manufactured in special molds to standard sizes. They are more expensive, but due to the integrity of the structure they have increased strength and a long service life. The cast structure is made entirely of steel, which provides the foundation with high reliability. This pile-screw foundation receives only positive reviews.

Piles with welded tip

• This is a metal pipe, pointed at the bottom. Blades are welded onto the sharp end, which are made by cutting metal. The tip is treated with anti-corrosion compounds.

• The diameter of the pipe used may vary. This manufacturing method allows the use of products of sufficiently large diameter. There are several types of blades:
  • single blades;
  • double blades.
• The double screw prevents distortion and ensures maximum structural reliability.

Scope of application of pile-screw foundation

Foundations are chosen based on the geology of the site. The soil features that force the use of screw piles are as follows:

• weak soils (filled, marshy);
• high groundwater level;
• swampy area;
• location of the construction site in water;
• high degree of unevenness of the terrain.

In all these cases, the use of a concrete foundation is undesirable, since it will not provide a reliable foundation for the house. In addition, serious waterproofing will be required to protect the material from moisture penetration, since concrete is still a more porous material than steel.

Screw piles are an ideal solution for such types of construction as:

• low-rise individual housing construction;

• small buildings requiring short construction times;
• strengthening slopes and slopes;
• supports for power lines;
• supports for lamp posts and billboards.

The products can be used in the construction of a private house from timber, logs or frame housing construction.

Advantages and disadvantages of a pile-screw foundation

Screw piles are now quite widely used in the construction of private houses, but before choosing a house on a pile-screw foundation, it is necessary to study their positive and negative aspects. The advantages include:

• strength due to the use of steel as a raw material;
• durability, the service life of such a base can reach 150 years if the manufacturing and installation technology is followed;
• low cost of the product itself and its installation;
• simplicity and high speed of installation;
• possibility of use in areas with difficult terrain, for example, on slopes;
• ensuring reliable operation on poor soils, such as sedimentary rocks, marshy areas;
• Possibility of reuse if necessary.

Simplicity and speed of installation are possible due to the fact that:

• lack of preliminary soil development (digging trenches or pits);
• there is no need for complex special equipment;

• the simplicity of the technology does not require special skills and knowledge;
• unlike concrete foundations, you do not need to wait 4 weeks until the structure is completely ready.

All these positive characteristics have allowed screw piles to become widespread, but we should not forget about the negative aspects. Especially if their consequences can be prevented in time.

Pile screw foundation video

Pile screw foundation disadvantages:

• corrosion of metal;
• limited bearing capacity;
• impossibility of installation close to the walls of an existing building;
• impossibility of arranging a basement in the house.

Corrosion can be avoided by treating the material with special compounds. During individual construction, there are no large loads on the foundation, so the second point does not become significant. With an impressive list of advantages and a small number of disadvantages, which are rather features of operation and are completely preventable, screw piles become an excellent support option for a private home.

Calculations of a pile-screw foundation

Basically, calculations are made to determine the diameter, length and pitch of piles. These values ​​are influenced by the type of soil and the weight of the structures of the future house.

• The type of soil can be determined using geological studies. For individual construction, the procedure is simpler: a hole is dug, approximately 50 cm deep, and the soil is analyzed. If layers with sufficient strength have already begun at this depth, a pile length of about 2.5 m can be used.
• If the site has lenses of poor soil, quicksand, or it was not possible to reach a soil layer with good characteristics, it is better to take a length with a margin to prevent possible problems. On fairly poor grounds, the required length can reach 3-4 m.

• For private construction, piles with a diameter of 108 mm are most often used. Calculation of the pitch of piles depends on their required number. This is where the need arises to collect loads from the house.
• In order to calculate all the loads, it is necessary to determine the materials used, the dimensions of the building and the main dimensions of the load-bearing elements. The load is calculated based on:
  • ceilings together with the floor structure;
  • walls with decoration;
  • partitions;
  • roofing taking into account the roof covering;
  • snow cover, which depends on the construction area;
  • furniture and equipment, for residential buildings 150 kg per square meter of the total area of ​​the building is accepted.
• To find these values, you need to calculate the planned volume and multiply it by the density of the materials used. To ensure a margin, it is allowed not to subtract window and door openings from the volume of the walls. The found value is multiplied by 20-30%, which will provide a safety margin for the load.
• Depending on the characteristics of the base, a screw pile with a diameter of 108 mm can withstand from 4 to 9 tons. The number obtained from collecting the loads is divided by the value of the load-bearing capacity (if there are doubts about the characteristics of the soil, it is better to take the minimum value) and the required number of products for the foundation of the house is found. Next, this amount is evenly distributed around the perimeter of the building.

Pile screw foundation technology

Screwing piles can be done using special equipment or manually. Regardless of the chosen method, the base is first prepared. Preparation work takes place in the following order:

• starting point selection;
• carrying out the location of the piles on the ground;
• marking with twine.

The work is carried out with special care, the dimensions must match down to the millimeter. Otherwise, problems will arise with the structure of the grillage and the normal distribution of loads.

Screwing using special equipment

• It is better to entrust such work to professionals. The installation process is carried out using a heavy-duty machine equipped with a special installation. First, the equipment is brought to a given position and secured with outriggers, after which the accuracy of the location is checked and the screwing process begins. The machine moves to the next position. The method allows you to complete the work in the shortest possible time.

Screwing by hand

When building a foundation yourself, it is difficult to rent special equipment and master it, so the most competent solution would be to use physical force. Driving piles with your own hands requires the following tools:

• shovel for leveling the surface;
• construction level to ensure accuracy of work;
• tape measure;
• a metal scrap with two pipes with a diameter of 50 mm as a lever for screwing;
• hammer or small sledgehammer;
• garden auger;
• grinder for cutting the top of the pile;
• gloves and overalls.

A garden drill is used with a smaller diameter than the selected piles.

Stages of work

• Drilling holes with a smaller diameter than the piles using a garden drill. The depth should be shorter than the length of the pile. The hole in this case serves as a guide and ensures installation accuracy. Screwing starts from the corners;
• installing a pile in the hole, attaching a level to it and threading a crowbar, which will serve as a lever;
• The screwing process is carried out under constant vertical control. This is why the level was set. Several people press on the levers, but unevenly, so the pipe may move away from the design position;

• as you go deeper into the ground, pipes are put on the scrap, thereby increasing the lever arm, which allows you to apply less force;
• after screwing in one corner, move on to the other;
• Having completed the work on the corners and checked the accuracy of the installation, proceed to screwing in the intermediate pipes;
• cutting metal pipes to obtain one level;
• device for cutting grillage piles.

The grillage for this type of foundation depends on the material of the house and can be made of:

• timber;
• glued boards;
• metal corner;
• metal channel;
• T-beam;
• in a house made of timber or logs, the first row of wall fencing can become the strapping.

The arrangement of a grillage is necessary for the coordinated operation of individual piles. Thanks to the piping, even if one of the pipes fails, the house will continue to stand firmly.

• The pile will not enter the ground strictly vertically; it will need to be constantly leveled and returned to the design position, so it is better that the work is carried out by at least three people: two act on the lever and one checks the accuracy. To prevent it from moving, special devices are sometimes used to fix it.
• If, while screwing, an obstacle or a layer of dense soil is found in the path of the pile, the penetration depth and location are analyzed. If it is not located at the corners of the house and you manage to insert it into the ground a meter or more, you can simply cut off the top and leave everything as is. With a depth of less than a meter, there is a possibility of the house skewing. At the corners, the piles should be installed to their full length, since these are the most critical areas.
• The final stage of installation may be concreting. It will provide additional reliability, but this process is not necessary in the case of screw foundations.

Cost of a pile screw foundation

• The total price of a pile-screw foundation depends on the dimensions of the building. The most common piles of 108 diameter can be purchased at a price of 1900-3000 rubles. per set depending on the required length. The cost of installing such a pile is approximately 2000 rubles. When installing it yourself, you will need to add the price of tools to the total cost. It turns out that for screwing one pile you will have to pay from 1900 to 5000 rubles, depending on the installation method.
• You also need to take into account the cost of the grillage, if any. As an example, we can cite the price of a turnkey pile foundation for a house measuring 6 by 6 m. With good soil characteristics, it will be less than 30,000 rubles. If the question is how much does a pile screw foundation cost, then as an example we can give a calculation for a building measuring 10 by 10 m, in this case it will be from 70,000 rubles, and a pile field of 12 by 12 m will cost about the same.

Screw piles are an excellent solution for the construction of light private houses; they will allow you to obtain a reliable and durable foundation for a small building in the shortest possible time at low cost. The ability to choose the design and installation method gives them another advantage over other types of foundations. However, it is important to remember that such supports are not suitable for a heavy brick or stone house, since their load-bearing capacity is insufficient to withstand such loads.

The construction of a building must be approached thoughtfully, carefully calculating all stages of construction. And first of all, you need to decide on the type. But what to do if on your site you encounter so-called “difficult” soils, which include:

• Peat bogs;
• Wetlands;
• Areas with groundwater;
• Areas subject to frost heaving forces;
• Flooded areas.

In this case, one of the fastest and most reliable ways to solve the problem is to use a pile-screw.

We can highlight the main advantages of a pile-screw foundation:

• Installation is carried out within one to two days;
• No leveling of the site's terrain is required;
• There are no large-scale earthworks;
• Screwing of piles is carried out in all weather conditions.

The main disadvantages of a pile-screw foundation include:

• Impossibility of installation on rocky terrain and in areas with hard limestone layers or rocky soil;
• Foundation piles cannot be installed closer than 0.5 meters to an already built house, and installation in this case is difficult due to the use of special levers;
• When choosing a pile foundation, the construction of a house with a basement is significantly complicated. And such a foundation for a building becomes unreasonably high.

To calculate the foundation, you can use a table that can be used to determine the bearing capacity of a screw pile depending on the soil.

The minimum depth for screwing piles for Moscow and the Moscow region is 1.5 meters, which guarantees the installation of a pile foundation below the depth of soil freezing. the installed screw pile Ø108 mm is capable of bearing a load of 5 tons.

Features of installation of a pile foundation

Screwing in screw piles can be done either mechanically - using a machine equipped with a hydraulic drill, or manually - by several people.

With a mechanical installation method, it is easier to control the required screwing force. This method also allows you to more accurately center the barrel. This ensures higher installation accuracy. The maximum deviation of the screwed-in pile shaft from the vertical axis should not exceed 2 degrees.

After the pile is screwed in to the required depth, its upper part is cut off. To ensure that the edge of all piles is set to the same level, it is necessary to use a laser level.

Then, concrete solution is poured into the pile shaft. Contrary to popular belief, concrete is poured not to strengthen the pile, but to displace oxygen from it and thereby prevent corrosion of the metal from inside the shaft. If the exposed pile is not concreted, then with the arrival of winter it may fill with water and burst.

What else should you pay attention to when installing piles?

• You can determine that the pile is screwed in all the way, or as installers say: “it has failed,” by the severe deformation of the metal of the barrel eye;
• Users of the site recommend using the following technique when pouring concrete into the shaft: underfill approximately 20 cm from the top level of the pile, and fill the remaining part with a dry cement-sand mixture. This is done so that this material will draw out the remaining moisture from the trunk;
• After welding the heads, the piles are tied horizontally to each other. Most often, a beam or metal profile is used for this purpose. If during the process the piles protrude above the ground surface by more than 1 meter, then in order to impart rigidity to the entire structure, additional profiles - jibs - are welded to the trunk at an angle.

Pile foundation: possible mistakes

• When installing a foundation made of piles, it is not allowed to set a single level of piles by twisting them. This will lead to the fact that the compacted soil will be loosened, and when installing the house, the pile will sag exactly the distance that was loosened due to its twisting;
• Also, one of the most common mistakes is that the pile is screwed into a ready-made, pre-dug hole. the so-called “pit” should not exceed 30 cm.

Watch the video on how to manually install a pile foundation.

This page contains information about the pile-screw foundation: calculation of the foundation, materials for construction, we build a pile-screw foundation with our own hands, videos and prices are shown on the page. We will tell you where you can order a foundation in Moscow.

Pile-screw foundations- this is a type of foundation that is rapidly gaining popularity, which is characterized by high construction speed, cost-effectiveness and excellent performance characteristics. This is the optimal foundation option for wooden houses, buildings made of foam concrete and gas silicate, as well as for small brick buildings.

The page discusses in detail the technology for calculating a pile-screw foundation, the features of its construction with your own hands and the current prices for the construction of pile foundations when using the services of construction companies.

Fig 1.0: Construction of a frame house on a pile-screw foundation

Calculation of a pile-screw foundation

Correct calculation is a necessary condition for the reliability and durability of a pile-screw foundation, therefore its implementation must be approached with maximum responsibility.
First you need to determine which type of piles is suitable for the type of soil on which you plan to start construction.

Fig 1.1: Piles with a widened support heel

In Figure 1.1 depicts piles intended for use in problematic soils - floating, loose and prone to heaving. They are distinguished by a widened heel, which improves the fixation of the structure in the soil and increases its load-bearing capacity. The wall thickness of such piles can vary from 4 to 16 mm, length - 3-15 meters, diameter - 159-325 mm.
One pile with a widened heel, depending on the size, has a load-bearing capacity of 1-3.5 tons. They are placed in increments of 3 meters from each other. The estimated cost of the pile is around 3,500 rubles.

Rice. 1.2: Standard screw piles

In Figure 1.2 depicts piles used in ordinary soils. This is the best option in terms of price-performance ratio, which can be used for the construction of light houses made of wood or aerated concrete, one-story brick buildings and fences.

The length of such screw piles varies from 2.5 to 15 meters, diameter - from 47 to 325 mm, load-bearing capacity - from 0.7 to 2.5 tons. According to SNiP requirements, they must be placed in increments of 2.5 meters. The cost of one pile starts from two thousand rubles.

Rice. 1.3: Hollow screw piles

In Figure 1.3 you can see screw piles for dense soils, sandstones and permafrost. Such designs differ from other types in the absence of a tapering tip; they are hollow inside and at the same time have open ends. During the driving process, such piles are filled with a column of soil, which provides additional fixation.

Hollow piles, as a rule, cannot be concreted. However, if it is necessary to give the pile foundation maximum load-bearing capacity, after immersion, the soil is removed from the pile with a bailer and concrete solution is poured into the pipe. This technology allows the construction of large brick buildings (3-5 floors) on pile-screw foundations, even in swampy areas or permafrost.

Rice. 1.4: Hollow piles for permafrost soils

The wall thickness of hollow screw piles can be 8-20 mm, the diameter is either 219 or 325 mm. Length - 4-16 meters, load-bearing capacity up to 4.5 tons. The cost of one hollow pile starts from 4.5 thousand rubles.

If you plan to build a wooden house on a pile-screw foundation, the piles must be completed head. You can see it in image 1.2:

Rice. 1.5: Head for screw piles

The dimensions of the head are the same for all types of screw piles; depending on their diameter, only the size of the landing socket differs.

Fig 1.7: Types of grillages for pile-screw foundations

Related materials

Calculation method for a pile-screw foundation

Calculation of a pile-screw foundation for the construction of 1-2 storey wooden and brick houses is carried out according to the following algorithm:

• We determine the mass of individual elements of the future building;
• We calculate the load from precipitation (snow and wind) that will be exerted on the building;
• We calculate the total load of the building on the pile-screw foundation;
• Based on the area of ​​the building and the standard distance between individual piles, we determine the number of required piles;
• Based on the load-bearing capacity of different types of piles, we determine the appropriate standard size of piles;
• We draw up a drawing of the pile field based on the standard step between the piles;
• Based on the standard size of the selected piles and the calculated load from the building, we determine the grillage parameters.

Fig 1.6: Pile-screw foundation with metal grillage

How to determine the weight of individual parts of a structure?

This is done based on the standard weight of the materials used in construction and the total area of ​​the building.

Walls:

• From timber - 600 kg/m3;
• From brick - 600-1200 kg/m3 (depending on what kind of brick is used - monolithic or hollow);
• From aerated concrete and foam block - 400-900 kg/m3;
• From frame panels (up to 150 mm thickness) - 20-30 kg/m3.

Roof:

• From slate - 60-80 kg/m2;
• From tin or sheet steel - 20-30 kg/m2;

Interfloor ceilings:

• Wooden - 70-100 kg/m2;
• Tsokolnoe - 100-150 kg/m2;
• From a monolithic concrete slab - 500 kg/m2;
• From a hollow concrete slab - 350 kg/m2.

The average household load on the foundation is 100 kg/m2.

How to determine the atmospheric load on a building?

• h is the total height of the building (from the bottom point to the ridge);
• S is the area of ​​the building.

Snow load depends on the climatic conditions of a particular region. Here are the average data for different territories:

• Black Earth and southern regions - 50 kg per m2;
• Middle strip - 100 kg/m2;
• Latitude from Arkhangelsk to Novgorod - 150 kg/m2;
• North of Arkhangelsk - 200 kg/m2;
• Siberia - 350 kg/m2.

We determine the number, diameter and required length of piles

When calculating the actual number of piles, it is necessary to take into account the area and weight of the structure. The minimum pitch between piles on ordinary soils at mid-latitudes should be at least 1.7.

The maximum step is determined by the type of structure:

• For log houses or houses made of timber and frame buildings - 3 meters;
• For buildings made of aerated concrete, cinder block and foam block - 2.5 meters;
• For brick buildings - 2 m.

If the step is less than the norm, the foundation will move, since the soil will not be able to evenly distribute the load coming from the piles; if the norm is exceeded, there is a high risk of the foundation settling under the weight of the house.

It is also necessary to take into account that one pile should be installed at each corner of the house and at the intersections of walls.

Fig 1.7: Log house on a pile-screw foundation

The required load-bearing capacity of piles is determined by dividing the total mass of the structure and the load from precipitation by the number of piles. Knowing what load-bearing capacity the piles should have, it becomes possible to select the appropriate diameter of the screw structures.

For the construction of foundations for one-story frame houses, as a rule, screw piles of the 89th are used diameter, for houses made of timber and foam concrete - 108, and for one-story brick buildings - 133.

Pile length is determined based on the characteristics of the construction site - the type of soil, the depth of its freezing and differences in height at the construction site.

According to the requirements of SNiP, a geological study must be carried out for this, but at home you can use an ordinary garden drill (you need to drill until you begin to remove dense lumps of yellowish clay from the hole).

Fig 1.8: Correct placement of the pile in the soil

It is also necessary to take into account differences in height at the construction site. A situation is possible when, in order to ensure the same height of the caps, it is necessary to use piles of different lengths.

Preparatory work, materials, tools

To install a pile-screw foundation with your own hands, you will need the following tools:

• Scrap and scraps of metal pipes (50 mm in diameter, 2.5 m long), which will be used as levers for screwing in the pile;
• Hose and magnetic level;
• Garden drill for creating guide holes, its diameter should be less than the diameter of the screwed piles;
• Shovel and cart for transporting soil from a construction site;
• Grinder for cutting piles;
• Tape measure and marker;
• Welding for fastening a metal grillage or caps.

As for materials, in addition to the screw piles and grillage themselves, you will need a wear-resistant primer for metal. Priming metal piles ensures their protection from the aggressive effects of groundwater. If you neglect this point, over time the bearing capacity of the piles will greatly decrease.

Preparatory work before starting work consists of clearing the construction site of vegetation and debris, after which all necessary tools and materials are delivered to the construction site.

Related materials

Fences on screw piles

In suburban construction, when constructing fences for summer cottages, forestry areas, farms and agricultural enterprises, laying a concrete foundation is, as a rule, not required. Posts on screw piles are used as fence posts.

DIY pile-screw foundation

The construction of a pile-screw foundation is carried out in the following sequence:

• The position of the piles is marked according to the design data. To mark the places where the piles are screwed in, reinforcing pegs or wooden blocks connected to each other with twine are used. First of all, a “starting line” is created, which is one of the walls of the building, based on it further marking is carried out

Fig 1.9: Marking the place for screwing in piles

• Next, the piles are primed in 2 layers, after the coating has dried, work on screwing them begins. First of all, the installation of a corner pile is carried out at the highest point of the construction site, then - diagonal to it and the remaining piles in the corners. Using a garden drill, a guide hole is created in the place where the pile is screwed in; its depth should be half a meter less than the length of the pile.

Rice. 2.0

• A pile with a magnetic level attached to it is placed in the well. A crowbar is threaded into the holes on the pile, and pipe scraps are placed on the ends of the crowbar. Using a crowbar as a perpendicular lever, the pile is screwed in; this requires at least 2 people.

Fig 2.1: The process of screwing in a screw pile

• After all the piles are immersed in the soil to the required depth, the trunks are trimmed. A hose level is used to determine the exact cutting height.

Rice. 2.2: Trimming a pile trunk with a grinder

• Whether to concrete screw piles or not is entirely up to you. If the diameter and length of the piles are chosen correctly, their load-bearing capacity will be sufficient without concreting, in which case you will only incur unnecessary costs. If you still decide to use concrete, to prepare the solution poured into the pile cavity, use cement of a class not lower than M300.

Rice. 2.3: Concreting the shaft of a screw pile

• To create a grillage for a pile-screw foundation, I-beams or channels can be used; for the construction of light frame houses, timber can be used; for brick houses, a monolithic concrete grillage can be used. If the grillage is metal, it must be primed to avoid corrosion in the future. The strapping is performed by welding the grillage to the pile shafts. To give the structure greater rigidity, reinforcing bars are welded to the junction of the grillage and the pile.

Fig 2.4: Attaching a grillage from a channel to the shaft of a screw pile

Pile-screw foundation video

For a better understanding of the technology for constructing a pile-screw foundation, check out the videos that explain the most important aspects of construction.

Video #1- How to mark places for screwing in piles on a construction site

Video No. 2- We twist the screw piles with our own hands

Video No. 3- How to correctly mark piles before cutting

Video #4- Features of installation of a concrete grillage

Part 1

Part 2

Pile-screw foundation - prices

The cost of such a foundation depends on the number and size of piles used to create the foundation. For your information, here are the average prices for foundations of different sizes:

Foundation size	Number of piles	Cost (thousand rubles)
For a wooden bathhouse 6*6 m.	9	30
For a frame house 6*4 m.	12	40
For a log house 6*9 m.	18	63
For a house made of foam blocks 6.5*6.5 m	16	66
Under a brick house 8*8 m	24	95

Pile-screw foundation reviews

We bring to your attention reviews from people who have experience in independently constructing pile-screw foundations.

Oleg, 30 years old, Moscow:
“I recently completed the construction of a wooden bathhouse on a pile-screw foundation. All the work was done with my own hands, two friends helped. I can only say positive things about the foundation - it was not expensive, all the piles were screwed in within two days. I was pleased with the pace of construction, because I had to wait for the concrete to harden It would take a very long time to build a strip foundation. I recommend it!"

Dmitry, 35 years old, Zelenograd:
“I have been working in a company engaged in the construction of pile-screw foundations for 10 years. They are ordered, as a rule, for light wooden and foam concrete houses, less often for brick ones. Among the advantages of such a foundation, I can highlight the speed of construction and low cost. Among the disadvantages are: the difficulty of constructing it yourself. If you want a pile-screw foundation to be reliable and durable, it is better to entrust its construction to specialists"

Reasons to contact us for a screw foundation

If, after reading this article, you got the impression that it is extremely difficult to build a pile-screw foundation with your own hands, you are not far from the truth, in practice it is so.

Firstly- actual construction must be preceded by detailed calculations, which can only be fully carried out by specialists.

Secondly- how reliable a pile foundation will be depends heavily on compliance with all the norms and rules of its construction technology, which are simply impossible to take into account without proper experience.

If you do not want to risk your money and time, and want to get a high-quality pile-screw foundation, contact the Bogatyr construction company.

We guarantee that:

• The foundation will be built in the shortest possible time - mechanization of the work process makes it possible to implement any project within several work shifts;
• To create the foundation, only high-quality materials will be used - we have been working with one pile manufacturer for a long time, the quality of its products has been repeatedly tested in practice and does not raise any doubts;
• All calculations, from analyzing the bearing capacity of the soil to determining the required standard size of piles, will be performed by the best designers.

"What about the prices?" - you ask? Our prices are more than adequate. In Moscow and the region there is not a single construction company engaged in the construction of pile-screw foundations at prices lower than those offered by the Bogatyr company.

Articles on the topic

Useful materials

JQuery(document).ready(function())( jQuery("#plgjlcomments1 a:first").tab("show"); ));

Modern technologies have somehow, completely imperceptibly, brought into our lives another innovation, previously available mainly only to military personnel and geologists (lovers of hard-to-reach places) - a screw foundation. At the same time, the relative simplicity and speed of creating such a structure using special piles gradually “pushes” aside the strip and column foundations that are familiar to us.

But is such a foundation really a universal solution for building a strong and durable foundation for a house? In the article we will tell you how to make it, give detailed step-by-step instructions,

Screw pile

This is a metal pipe (treated with a special compound that slows down the corrosion process), to the lower pointed end of which a blade is welded. Such a pile is screwed (screwed) into the ground (like a self-tapping screw into wood), practically without damaging it (only compacting it due to the immersion of the pipe) and, therefore, absolutely without reducing its load-bearing capacity.

These piles are available in several types:

• with a helical blade (used on soils with poor load-bearing capacity) or imitation threading along most of the length of the pile (such piles are usually used in northern regions, where it is necessary not to particularly disturb the permafrost when laying the foundation for buildings and structures);
• with different pipe diameters - the larger the diameter, the larger the weight of the building the pile can support (without its deformation), but do not forget that thicker piles (whose diameter exceeds 108 mm) cannot be tightened manually;
• with different blade diameters - for less durable and water-saturated soils, the blade diameter will be larger than for dry and dense soils.

And, of course, the type and shape of the pile also depends on the manufacturer that produces it.

The screw foundation looks like this:

• in the corners and at the intersections of internal walls, as well as along the length of the wall of the structure, piles are screwed into the ground (the pitch of the piles ranges from 1 to 3 meters);
• on top, all piles are cut to the same level and fastened with either metal or wooden beams to create a single rigid structure - a grillage;
• Between the ground level and the bottom of the building (grillage) there is a freely ventilated space.

Advantages and disadvantages

This is a fairly simple design. However, here too there are pitfalls waiting for you:

• piles should be selected strictly in accordance with the calculation made by the designer based on hydrogeological surveys on your land plot, the depth of soil freezing, as well as the weight of the future building and the weight of the snow cover applied to the building in winter (otherwise you risk either overpaying for piles of greater length or diameter, or get a completely unstable structure that will “drive” within a year);
• depending on the soil, it can be quite difficult to screw piles into the ground manually (even if 4-5 people take part in this process);
• the presence of trees, tall bushes, fences or other structures in the immediate vicinity of the foundation site creates problems for driving piles manually;
• Not all companies do their work efficiently, following technology.

However, a screw foundation also has advantages:

• no extensive excavation work is required;
• can be installed on any terrain, without prior leveling of the terrain;
• work on driving piles into the ground is carried out almost at any time of the year.

The foundations can be laid on any soil except rocky, since the rock itself is an excellent strong foundation (for a strip or columnar foundation).

Preparatory work

It is quite possible to make the base for a small building (garage, gazebo, veranda, one-story wooden frame house):

• you can weld the pile yourself, using the drawings posted on the Internet, or weld the piles in a similar way (for this you will need to order a calculation, and then purchase one recommended pile at the factory);
• You can also immerse the piles into the ground yourself (with the help of friends), guided by the existing drawings when arranging them, and make a grillage.

For a screw foundation, you should not skimp on material. Piles should only be made from new pipes of the required thickness, and they should be thoroughly cleaned of rust and coated with a protective compound. Particular attention is paid to the quality of the welding joint at the point where the blade is attached, since on sufficiently dense soils the seam may burst, unable to withstand the load applied to the pile.

To facilitate the process of screwing the pile in its upper part (which you will then cut with a grinder), you need to make two holes - into them you will insert “bars”, with the help of which the pile is screwed into the ground.

Installation should be carried out as accurately and competently as possible. The maximum permissible error along the vertical section and between the piles is no more than 2 cm. Otherwise, in the future you may face the need to repair the grillage due to its sagging. And this, in turn, will lead to damage to the load-bearing wall and even skewing of the building.

The foundation on screw piles must be located so that the load on it and on the ground is distributed as evenly as possible. So take the house plan and break it down into rectangles. Support blocks should be located on their sides and diagonals, taking into account the required distance between them. In this case, each pile must be located in the center of all load-bearing beams of the house.

So, divide the house plan into rectangles, having previously determined the size of each of them. So, you can calculate the number of piles and distribute them over the area so as to evenly distribute the load on the foundation. After completing the planning, transfer the markings from the paper to the surface of the ground on which the house on stilts will stand. Drive in pegs at the pile installation points.

Stages of work

The work is performed in the following sequence:

• Dig a leader hole for each pile (just remove the top layer of soil with grass in this place), the depth of which should not exceed 10-15 cm, and the width should be 2-3 cm greater than the diameter of the pile blade. Some professionals advise doing without digging leader-holes, which increases the stability of the pile, but at the same time increases the effort to screw it into the ground manually. You cannot dig deep holes and simply install piles in them, deepening them only a few tens of centimeters. One of the necessary conditions for high-quality immersion of screw piles is the intactness of the soil around it, which allows the pile to transfer the load from the structure not only with the lower end and blade, but also with its entire lateral surface.

• Install the pile and, together with your assistants, screw it into the ground using a special rod, constantly checking its vertical position. The pile should sink into the ground below the freezing level of the soil in winter.
• Align the top of all piles to one level (mark it on each pile using a level), cut off the excess with a grinder.
• Pour concrete into the pile (this will increase its strength and reduce the rate of metal corrosion).
• Weld a metal plate (at least 8-10 mm thick) to the top of each pile, protruding several centimeters beyond the boundaries of the pile on all sides.
• Create a grillage by attaching the beams to the plate using welding or bolts.

Video

Learn everything about arranging a screw foundation by watching the following video: