A dry mixture or solution is poured into the piles. Concreting screw piles - is it necessary? What is important to remember when concreting piles from the inside

used to prevent corrosion inside the screw pile shaft.
The entire internal part of the screw pile from the bottom to the top is filled with concrete mortar. During backfilling, it is necessary to avoid the formation of caverns (voids) inside, at the junction of the concrete and the pile shaft. The top of the pile is covered with a head or channel. If it is planned to cast a concrete slab or strip on installed screw piles, then the inside of the screw pile is not filled with concrete; reinforcement is placed inside the shaft, which is then secured with a reinforced mesh throughout concrete structure. Concrete is cast into the shaft of a screw pile and fills the entire remaining area of ​​the future foundation, which makes it possible to create one common reinforced concrete structure.

Finishing of screw piles

Finishing of screw piles- how to do this? - sometimes you can hear such a question. The fact is that a screw pile is a ready-made product intended for the rapid installation of a foundation. Screw piles treated with a special anti-corrosion compound and are ready for use.
By finishing screw piles we mean giving additional protection product. To do this, the upper part of the screw pile, located above the ground surface, is covered with an additional layer of anti-corrosion mastic, covered with geotextile and primed again. The versatility of using screw piles lies in the fact that no special finishing is required.

Preparing a screw pile

Before backfilling the pile shaft with concrete mixture, the height mark of the piles is made to one specified level. The piles are cut according to the mark. Afterwards, caps or channels are mounted on the upper parts of the screw piles.

Cutting to level and filling screw piles with concrete

After the shafts of the screw piles are aligned to one level, they are filled with a pre-diluted concrete mixture. A pipe or a 150 cm stick is used to compact the concrete inside the pile shaft.

screw piles, concreting, marking the pile shaft at a given level
Carrying out work on filling the pile with concrete mortar.

The pile filled with concrete mortar is “tied” with a channel or a steel cap is installed on top, on which the building structure is then attached.

Installation of a pile foundation in the evening

Often the time for installing a pile foundation ends in the evening.

There is such a thing as a screw pile - a metal pillar with a screw blade on one side and a technical hole on the other. These products are used to reliably strengthen the foundation under the house. They are a guarantee of the strength and durability of the structure. But for this it is strictly recommended to concrete them. Concrete increases the resistance of pillars to external loads and ensures their long-term functionality. A high-quality concreted pile will last several times longer than one reinforced with zinc, and besides, it costs much less.

Why is concreting necessary?

It is necessary to concrete the screw piles to avoid corrosion inside the core of the product, that is, to displace air from the inside of the pipe. In addition, concrete increases the strength of the screw pile and saves money.

Brands of concrete used

Before starting work, you need to find out which concrete is best used to strengthen the screw post. Usually, low-fraction concrete M200, M300 is used for concreting.

Brand M200 is most often used for the construction process of single-story or two-story houses with light overlap. This brand is used when working with reinforced concrete products; according to its strength characteristics, it is classified as structural.

The M300 grade is suitable for the construction of foundations for private houses up to five floors high. It is recommended to adapt such concrete to monolithic types of floors.

Technology

To conveniently pour concrete, you must first prepare a watering can with water. The reinforcement must be immediately cut and inserted to size. If there are not too many piles, it is recommended to mix the concrete with your own hands, with a shovel in a plastic container. It is important to remember: for reliable and durable concreting, it is worth adjusting the rods in height.

After construction work There may be mounting holes left in the concrete, which should be sealed with ordinary paper tape. Later, when the concrete has hardened, the tape can be removed.

Preparation of materials and tools

The choice of materials for the construction of a pile foundation must be responsible so that later you do not have to deal with undesirable consequences. Most often, it depends on factors such as the type of pillars, the method of their manufacture, immersion in the ground, and location during the construction of the building.

A pile foundation requires a large amount of construction equipment, so when it comes to dachas and residential cottages, it is necessary to consider those design options that can be built with your own hands.

An important component of the product is the grillage. The grillage is the upper part of the foundation, the function of which is to distribute the load on its base. It has the form of slabs that unite the bases of the piles and serve as a supporting structure for them.

Trimming piles

The construction of a pile foundation involves preparing a perfectly flat surface according to the level of the piles. This is not easy to do without special equipment, because the distance between the ends of the piles is quite large, and it is almost impossible to determine whether the surface is perfectly leveled. The equipment helps to determine all parameters with accuracy. It is a specialized attachment for an excavator, which is attached to the top of the boom. Inside there is a powerful tool for cutting concrete, metal and other building materials. Working with such an attachment guarantees accurate cutting. The surface is leveled without visible imperfections.

Inserting reinforcement

There are different types of reinforcement in piles - non-prestressed, pre-stressed. They help secure structures. The pile must be installed strictly in the middle of the grillage to prevent distortion. Regardless of whether the structure is concrete or a screw pile made of metal, the technology is the same.

The structure is strengthened at the corners. The location of the next pile from the corner can be up to three meters, and the degree of deviation cannot be higher than two - in this case, the tendency to retain loads is significantly reduced. Builders say that the next day after installation it is quite possible to begin erecting the walls of the building.

Concreting

When concreting screw pillars, it is very important that no voids are formed in the concrete material in the place where the pile adjoins the concrete. Reinforcement is placed inside the trunk to strengthen the structure. Concrete is poured into the shaft of a screw pile. It then fills the entire area of ​​the foundation base, resulting in one large reinforced concrete structure.

Process Benefits

Screw piles for creating foundations are durable. A house with this design has the potential to last about a hundred years. They can be used on almost any type of soil. Earthworks when installing them, they are not at all necessary, because the soil underneath them practically does not freeze and does not swell. In addition to simple structures, full-fledged houses made of brick materials can be built on such pillars.

Concrete screw piles: concreting technology and advantages

Screw piles are readily used in the construction of private houses, dachas, and cottages. Professionals recommend concreting them to avoid corrosion of the metal inside the rods and strengthen the reliability of the base.

Concreting screw piles is a fairly simple task from a technological point of view. But some experts believe that this is not at all necessary.

Competent judgments of adherents of this theory

The method of increasing the load-bearing capacity of screw piles, as well as ensuring their corrosion resistance, arose from the method by which drilled injection piles are installed. This technology is used when building in areas with dense buildings - that is, the destruction of the foundation of neighboring structures is completely eliminated.
If the foundation is laid using drilled injection piles, it is assumed that auger drilling installations are used in the work. A reinforcement frame is installed into the well that was drilled with a hole drill - it is filled with water-cement and sand-cement mortars, then the pile is pressurized.
The technology of using the injection of solutions into the trunk of the guilty piles significantly increases the load-bearing capacity - this is why the strength, rigidity and elasticity of the piles for deflection increases. It is recommended to use sand-concrete mixtures diluted with water in the warm season. In winter, special additives are required to prevent freezing.

In the photo - pouring concrete on a screw pile

Some experienced experts believe that when filling piles, concrete can create planes - due to the fact that the composition is too thick. That is, the air from the barrel will not go anywhere. The ideal solution in this situation is to backfill with concrete-free M300, or TsPS - condensation, which will appear over time, will definitely concrete the mixture.

To calculate the required amount of mixture, use the formula:

V=p r h (m3),

where r is the radius of the trunk (m), n = 3.14, and h is the length of the pile (m).
It has been experimentally established that for every meter of pile shaft with D equal to 108 mm, 16 kg of mixture is required.

The futility of concreting screw piles - justification

Many people believe that there is no need to concrete screw piles - both contractors and customers think so. It is believed that the main danger due to which screw piles can fail is contact between metal and concrete; they simply have a different coefficient of thermal expansion.
Due to this feature of the materials, microcracks form inside the concrete mass - that is, a place appears for the accumulation of air and moisture. Due to this, the corrosion process is activated - the slow but sure destruction of the pile begins.

IN low-rise construction V recent years Foundations on screw piles are becoming increasingly popular. Despite the fact that this technology has been used in industrial construction for more than a hundred years, private homeowners became interested in it only in the early nineties.

The essence of technology

When building private houses on problematic soils, the main difficulty is choosing the optimal foundation. Depending on the problem with the soil, you can use screw piles or a “floating” slab.

Concrete foundations on screw piles have been known for a long time. On at the moment There are two types of piles available, differing in the way the screw is created. In the first case, sheet metal is welded to the end of the pile. In the second case, the piles are cast in a special form, as a result of which the screw is integral with the entire structure. In the construction of private houses, piles with welded sheet metal are often used.

The screw pile has one feature: being in fairly dense soil, it compacts it even more. As a result, the soil's resistance to various external loads increases.

The ability to vary the height of the piles allows it to be used in areas with significant elevation differences. If necessary, a pipe of equal diameter can be welded to the barrel.

In what cases is a concrete grillage used?

Concrete grillage is one of the most reliable methods of strapping. It has two key advantages - concrete strength and resistance to extrusion forces.

A grillage on concrete piles is suitable for the construction of houses made of brick, foam block, gas silicate and other non-plastic materials. It eliminates deflection under peak loads.

In addition to the construction of houses, pile grillage is used in other cases:

1. If you need to give the base a more aesthetic appearance. Siding can be installed on a concrete base; it can be repainted or plastered.
2. If necessary, insulate the space under the building or extend any communications.
3. During the construction of fences. IN in this case The grillage is used both for aesthetics and for installing brick pillars.

Fluid soils and very deep peat bogs are considered contraindications for installing screw piles. It is not recommended to install piles in rocky foundations. For rocky soils, screw piles with a cast tip can be used.

Concrete foundations on screw piles are mainly used for the construction of small country houses or cottages.

Video about a concrete foundation on screw piles:

Advantages and Disadvantages

A pile-screw foundation is not ideal. It has both positive properties and disadvantages.

Main advantages of the foundation on screw piles:

1. Ease and speed of construction. You can do it yourself within 1-2 days;
2. Cleanliness during construction. This distinguishes it from monolithic foundation types;
3. Low cost;
4. Reliability and durability;
5. can be installed at any time of the year;
6. Increased load-bearing capacity;
7. Possibility of repeated use;
8. An ideal solution for non-standard landscapes: large differences in height, limited space, etc.

There are also certain flaws:

1. In a house on a pile-screw foundation, it will not be possible to equip a basement;
2. The lower part of the building requires additional insulation;
3. A separate problem is the quality of materials. Ideally, piles should be purchased from manufacturers, but not from resellers. A fairly large manufacturer has its own research and development departments that test all manufactured products, issue permits and technical justification.

Construction of a pile-screw foundation with concrete lining

Before the construction of the building begins, the channel is primed with an anti-corrosion compound. This prevents the formation of rust and premature wear of the foundation. Concrete grillage on screw piles is used in the construction of buildings made of aerated concrete blocks.

Despite the fact that the types of piles themselves may vary, the use of combined materials increases the strength of the foundation. Therefore, reinforced concrete grillage is most often used in construction. To build the foundation you need:

1. Screw piles;
2. Iron fittings;
3. Special knitting wire;
4. Concrete mortar;
5. Formwork boards.

First, the piles are screwed in. A screw pile is a metal pipe with a sharp tip and a special spiral blade, thanks to which the pile is screwed into the ground, like a self-tapping screw. In addition, the blade reduces the pressure on the ground and eliminates the possibility of the pile being pulled out due to soil heaving in the cold.

IN normal conditions the piles are screwed in to a depth below freezing. In the Moscow region this depth is one and a half meters. Screwed-in piles must be cut to level.

Reinforcement is knitted onto the installed piles. Its diameter should be in the range of 12-18 mm. The distance between individual reinforcing bars is 15-35 cm. The reinforcement is tied around the perimeter of the tape.

Holes are drilled in the top of the installed screw piles. Mortgages pass through them, where longitudinal rods of reinforcement are attached.

After installing the reinforcement, the formwork is installed. Then the concrete is poured. In this case, it is necessary to ensure that the upper edge of the pile does not extend beyond the concrete base. When pouring concrete, the inside of the screw pile is poured first. To avoid the occurrence of voids, the pouring is subjected to vibration using metal pipes. After this, the final filling of the space between the edges of the formwork is done.

Concrete strip foundation with piles - this is best option for the construction of relatively light buildings on complex sloping landscapes. In this case, the piles are also anchors that hold the foundation of the house during the changing seasons. In turn, the tape ensures uniform distribution of the load over the entire area of ​​the foundation.

Video with an example of constructing a concrete foundation on screw piles for a fence:

In one of the previous articles, we talked about how unscrupulous manufacturers and sellers of screw piles deceive customers. We figured out how the desire for savings can affect the quality of products and, ultimately, the strength and durability of the foundation.

This time it’s time to remember that it’s not enough to buy good screw piles - they still need to be installed correctly. And here, too, there may be some errors and “jambs” on the part of dishonest service providers. They can be difficult to notice right away, and in the end you will again have to pay for the reliability of the building.

As they say, forewarned is forearmed.

What are the consequences of incorrect calculation of a pile field?

Before installing a pile-screw foundation, it is important to know exactly how many piles are needed and at what distance from each other they need to be installed.

The most “harmless” consequence that can result from incorrect calculation of a pile field is an increase in the cost of materials necessary for tying and constructing a grillage.

In the worst case, the foundation will be unstable, leading to deformation of the floor and loss of stability of the building. Depending on the “severity of the symptoms,” you will have to install additional piles or build a new foundation.

What difference does it make - what's there, underground?

In order not to encounter underground “surprises” during the construction of the foundation, you need to pay sufficient attention to conducting geotechnical surveys.

What can the desire to save at this stage of work lead to? Part of the load-bearing capacity of the piles will be lost. The further consequences are easy to guess.

Screwed in, unscrewed, screwed in again...

Why do you think piles need a tip with a screw? To make it easier to screw them into the ground? This is partly true. But the propeller blades also perform another important function: they compact the soil underneath them, resulting in a more stable foundation.

Now let’s imagine this situation: the workers noticed that they had screwed in the pile too deeply, and it turned out to be lower than the others. How to improve the situation? The simplest (but not the best) solution is to unscrew the pile back to the desired height. Only after this it will lose its load-bearing capacity and will sag again in the future.

It’s even worse when the pile is installed in a pre-dug hole. Professionals will definitely never do this.

"Drunk" piles

Ideally, all screw piles should be installed strictly vertically. In practice, a small deviation is acceptable - no more than 2°. If this critical value is exceeded, the stability of the foundation will decrease. Such “drunk” piles should never be built up.

Do you need concrete?

Should I pour concrete into the pile shafts after installation? There are at least two reasons why this is worth doing:

• Concrete will protect the pile shaft from the inside from corrosion.
• If there is no concrete inside the trunk, then water will penetrate there, which, when frozen, can simply tear the metal.

Thus, concreting piles is not a procedure worth saving on.

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Judging by its ability to withstand external compressive forces, a screw pile has a significant margin of safety. Using the example of the most popular model of screw piles - with a diameter of 108 mm - from each individual pile you can expect a guaranteed holding of two tons, and this is only before concreting. This procedure will increase the load-bearing load of the screw pile by another third, and will not allow the pile to deform. increasing its elasticity to deflection, which is especially important when screwing in pile-screw foundations on hilly terrain.

It must be said that concreting piles solves, in addition to the issue of bearing capacity, also the problem of waterproofing. Thus, concrete prevents the penetration of moisture into the shaft of a screw pile, and this is a critical point in the technology, since it is not customary to treat the inside of the pile with protective coatings, and concrete here also acts as an adsorbent, keeping the piles intact from the inside.

Typically, piles are filled with a sand-concrete mixture, and the pouring level, as a rule, is somewhat deeper than the level of cutting the piles. It should be taken into account that after a short time the mixture will subside by several centimeters. Therefore, after pouring, either powdered concrete or cement is added to the pile. This is done to eliminate excess water and the logical completion of high-quality pouring of the pile.

If the temperature is above zero, the sand-concrete mixture is diluted with ordinary water, but when it freezes, you need to add a portion of a special anti-freeze additive to the solution so that the pile does not break due to the expansion of the frozen mixture. When installing a pile-screw foundation, the cheapest option for an anti-freeze additive is the most common table salt, preferably finely ground. Until the entire solution completely hardens, the salt will prevent the water from turning into ice. But this technique is especially good if the frosts are light and do not exceed five degrees. In severe frosts, you need to use special anti-freeze liquids. By neglecting this step, you run a high risk of losing both the pile and the mixture poured into it.

In central Russia, according to statistics, the level of soil freezing in winter rarely exceeds half a meter, so the lower part of the pile can be poured without additives, since the soil will have a positive temperature. Under a thick blanket of snow, the freezing level is even closer to the surface, which allows you to save a little on additives.

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Internal concreting of screw piles: pros and cons

Screw piles are considered a budget-friendly reliable foundation, the construction costs of which will be 15-20% cheaper compared to a similar concrete or tile foundation. One of the reasons for saving is that there is no need to involve expensive equipment that will mix the solution and pour the monolith. However, when installing screw piles, cement work may be necessary.

Why is internal concreting of screw piles necessary?

Load-bearing structure is the metal trunk itself, therefore pouring cement mortar inside the trunk does not impart rigidity to the foundation: here, rather, it has a protective function:

• - over time, moisture accumulates inside the screw pile, which begins to corrode the metal not only from the outside, but also from the inside. Hence the conclusion: the pile rusts almost twice as fast. Internal concreting eliminates the entry of water into the trunk;
• - with temperature changes, the water in the upper part of the trunk freezes. If the pile is small in diameter, the ice will not break the metal when it expands - there will not be enough force. If the pile is “108” in diameter, then there is a risk of negative influence of temperature changes.

There are also negative sides to this event. Firstly, additional financial costs. You will need little cement; it can be mixed manually, but installation time will increase. Secondly, a pile concreted from the inside can hardly be unscrewed and reinstalled. Therefore, for temporary structures like trailers on construction site There is no need for concreting.

Let's summarize:

• - if the screw pile is of small diameter (“57”, “76”), which is installed at a depth of 1-1.5 m and serves as a support for small structures, there is no need for concreting. For example, cement will not be needed for the construction of a gazebo or fence;
• - if you use load-bearing screw piles for a long-term foundation, internal concreting makes sense: the quality of such a foundation on screw piles and its durability will increase for several years.

In order not to ask questions about the need concrete works, as well as the choice of screw piles, contact trusted companies that will easily, quickly, and on a turnkey basis provide foundation repair and installation services of any complexity.

The Hermes-ZSK LLC company knows how to build a reliable house or industrial warehouse in the shortest possible time. We know how to please our clients with tact, responsibility and professionalism.

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Frequently asked questions | Ruuvipaalu Paalupiste Oy

What construction projects can be installed on screw piles?

Due to the wide range of sizes available, foundations can be created on screw piles for both small and large construction projects. Most recommended small construction projects are: terraces, fences, sheds, courtyard buildings, piers, etc. As foundations for small construction projects, manually installed screw piles can be used, the installation of which is easily carried out using an iron rod or rod. Among the larger construction projects, we can mention summer houses, cottages, workshops, arenas, pipelines, etc. Larger objects also require the use of larger screw piles, models of which are always installed by machine. For larger construction projects, it is advisable to conduct a soil survey (blade drilling) and use the services of a development planner.

What types of soil are most suitable for using screw piles?

The most suitable types of soil for the use of screw piles are clayey and sandy soils. Due to the large blade area, the screw pile has better load-bearing capacity than conventional steel pile. Due to the good load-bearing capacity, sufficient load-bearing capacity is often achieved already in layers of clay and sand. When using screw piles, the piles often do not need to be installed as deep as with driven piles, and thus the pile footage and costs are often significantly less than with driven pile foundations. In addition, installation of screw piles is better in clayey and sandy soils. Machine-installed screw piles can also be installed in moraine soils.

What is the difference between screw piles for manual and machine installation?

Screw piles for manual installation can be driven into the ground using an iron rod and similar levers. Manually installed screw piles are well suited for sites that require only a few piles or installation locations where access is difficult (such as an island). Screw piles for machine installation are driven into the ground using a hydraulic earth drill connected to a working mechanism. Machine-installed screw piles are suitable for projects that use a significant number of piles. In addition, screw piles equipped with blades with a diameter of 250 and 400 mm are models designed for machine installation.

Why do some screw piles have more than one blade?

The more blades are installed on a screw pile, the better its compressive and tensile strength is, achieved in cohesive types of soil (clayey soils). By increasing the number of blades, it is even possible to provide higher load-bearing capacity for shorter piles. Screw piles equipped with more than one blade are always pile models intended for machine installation.

At what depth should a screw pile be installed?

The blade of the screw pile must be installed no less than below the level of frozen soil. In this case, the foundation will no longer be sensitive to permafrost movements. The installation depth is also determined by the soil at the location where the pile is installed, the desired load-bearing capacity and lateral stability.

At what distance from each other should screw piles be installed?

Typically, the installation density is determined by the person designing the structure. In cases of small buildings, such as terraces and courtyard buildings, the gap between screw piles is usually about 1.5-3 m, depending on the mass of the structure, the soil and the strength of the bottom beam used.

What height should the screw pile be installed?

Screw piles are set to the correct height by rotating in a clockwise direction, in other words, tightening the bolt. Setting the height by rotating counterclockwise is not recommended, since in such a case the blade of the screw pile, when rotating, has already disturbed the soil layer in the area of ​​the bottom of the pile and subsidence of the pile may occur. A screw pile can also be cut in height using an oblique self-tapping screw if it is not possible to screw the pile to the desired height.

Is it necessary to fill the screw pile shaft with concrete after installation?

Usually, after installing a screw pile, its shaft does not need to be filled with concrete, but if groundwater are closer than 1 m from the ground surface, it is recommended to fill the pile shaft with concrete mortar, urethane foam or sand. By filling the pile shaft with concrete, the stability of the structure can also be improved and one-sided corrosion of the pile shaft can be avoided.

Is it possible to splice screw piles?

Hot-dip galvanized screw piles are joined using connecting sleeves secured with bolted joints; screw piles with an untreated surface are joined by welding. It is possible to supply extensions for piles 1 m long.

How can you build a pile?

For screw piles, there are several types of different fastening fittings, such as U-shaped support shoe, plate fastenings, bolted connections and pile caps. U-shaped support shoes, bolted joints and plate fastenings are well suited for attaching timber structures to screw piles. When extending a concrete-filled screw pile, a pile cap should be installed on the top of the pile. A steel entablature can also be welded onto the screw pile, on which a connecting or box plate can be installed, for example.

Is it possible to cover the base of a building in such a way that the screw piles are invisible under the building?

The cladding of the building's plinth can be made, for example, from wooden sheathed or acrylic plinth slabs, which give the impression of a real plinth. The remaining parts of the screw piles on the soil surface can be painted, plastic shrink sleeves or tubes can be installed on them, and they can be lined with bars with holes around their circumference.

How are the surfaces of screw piles treated?

All screw piles with shafts 60.3 x 2.9 mm are manufactured hot-dip galvanized (zinc layer thickness is approximately 110-140 µm). The wall thickness of larger screw piles is 6.3 mm and they are manufactured without surface treatment, since the thickness of the material takes into account the risk of corrosion.

What kind of installation equipment is used to install screw piles?

Manually installed screw piles are installed using an iron rod or other lever. You can also use a portable earth drill during installation. Machine-installed screw piles typically use an excavator, bucket loader, or other work machine to which a hydraulically driven earth drill is connected. Installation equipment comes in many sizes: from a mini-excavator weighing 0.8 tons to heavy excavators weighing more than 15 tons. Most of the installations are carried out using small-sized working machines that do not damage lawns and plantings.

Are calculation instructions available for screw piles?

Paalupiste Oy offers building planners instructions for carrying out geotechnical calculations for screw piles in Finnish. Designers are also given the opportunity to receive software for Pi-CAP pile calculations, which automatically calculates the correct size of a screw pile based on the specified target loads and the results of soil studies.

paalupiste.com

Questions about screw piles

Ask an engineer a question

1. How is the length of the piles that will be used for the foundation determined?

To determine the depth to which the piles will be installed, our specialists carry out test drilling. The elevation difference on the site is also taken into account. In order to determine the length of piles for a specific building, you need to contact us and agree on the time for the work to be completed.

2. I plan to build a house from rounded logs, size approximately 11x11 m. How many piles and what length will I need? The site is located in an area with clayey soil and there are elevation changes.

To create the foundation of a house of this size, you will need 25-30 screw piles with a diameter of 108 mm. The exact length of the piles can only be determined based on the results of a trial installation. You can find out more detailed information from the specialists of our company.

3. At what temperature can installation of screw piles be carried out?

Installation of screw piles is carried out at temperatures down to -15°C. To fill the internal cavities, concrete with special additives is used.

4. How long will it take to reconstruct the foundation under a 6x9 frame-panel house?

On average, such work takes from 2 to 4 days. The timing depends on the working conditions and the condition of the building itself.

5. How many and what kind of piles are needed to install a foundation for a 5x5 log bathhouse?

If the diameter of the log is less than 24 cm, 9 piles with a diameter of 108 mm and a length of 2.5 m will be sufficient. If you plan to use a log of a larger diameter, you will need piles of 133 diameter.

6. Is it necessary to fill piles with concrete and why is this done?

The cavity of the piles is filled with concrete to enhance the load-bearing capacity, as well as to prevent contact with the external environment and the formation of corrosion. Filling is not performed only in cases where the construction is temporary and the piles will need to be dismantled for their subsequent installation in another location.

7. Is it necessary to remove the turf on the site in order to install screw piles for the foundation?

To install screw piles, it is not necessary to remove the top layer of soil. During drilling, the grass cover is damaged only at the point of direct installation of the pile.

8. Is it necessary to insulate a pile-screw foundation and how is this done?

Like any other foundation, a pile-screw foundation requires additional insulation in order to prevent freezing of the lower part of the house and the utilities connected to it. The choice of a specific insulation solution depends on the characteristics of the structure. You can invite our specialist to determine the scope of necessary work.

9. Is it possible to install an extension to a house on screw piles? How will the installation be carried out in this case if there is very little space?

The possibility of constructing an extension depends on the condition of the foundation of the main building. Installation of piles in such cases is carried out manually; this does not require a lot of space, since the work can be carried out even in a very limited space.

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Wonderful modern screw piles are one of the best and most rational types of foundation. If such piles are used, it will be possible to solve many problems with the construction of the foundation. These structures can be installed by just two workers in a matter of hours, and the cost of screw products is quite reasonable. Thanks to their unique advantages, these piles have gained immense popularity today in our country and abroad.

Description

If a foundation of screw piles is installed under the building, then many aspects must be observed and taken into account. Such an aspect is competent processing and protective painting of products, appropriate functional recess, concreting of screw piles, installation of a grillage and slab, and others. If the structures were installed correctly and were filled with concrete, then this foundation can be built even on difficult soil with a large slope of the site.

Main advantages:

1. Rigidity
2. Durability
3. Affordable price
4. Easy quick installation
5. Can be installed in any soil
6. Ideal for difficult sloping areas

Why is concreting used?

Modern screw piles themselves are very strong and durable; this design is quite rigid and durable. Such products can withstand significant indentation and general extrusion loads, which ensures long term services of a unique pile foundation. To increase stability and rigidity, the pile is made of special resistant steel and has walls 4 mm or more thick.

Many builders ask themselves whether they need to fill screw piles with concrete, since these piles are already surprisingly strong and functional. If pouring concrete was used, the product will be able to support a total weight of approximately 30% more than without concrete. That is, each pile will be able to withstand even more weight from the building and will be of even higher quality and durability. Concrete will make structures even more rigid in deflection; this product will not bend when the soil acts from the side. Concreting is required if the area has large differences in height, as in ravines and others.

Also, concrete poured into the piles will protect them from water getting there, so if a person doesn’t know whether screw piles need to be poured with concrete, then the answer here will be unequivocal, concrete is required and what it should be good quality manufacturing. The pillars inside are not treated with anything, so the concrete there needs to be poured with concrete, and if the product remains hollow, then rust will quickly appear there, which is why the piles will collapse quite quickly.

Do-it-yourself concreting

If a foundation of screw metal piles is to be built, then the concreting process here is an important step. Concreting screw piles in this way will make them more efficient and durable. For pouring, sand concrete with grade M300 is usually used, and it is poured only below general level trimming the metal pile, this must be taken into account. Concrete is prepared quite quickly; if a special concrete mixer is used, it will take 5-10 minutes and no more. If the foundation is being repaired with screw piles, then it is also necessary to use concrete mortar.

Preparing concrete

To prepare concrete, you should pour one part of the cement into a concrete mixer, then pour in clean sand, it is recommended to do this in three stages. That is, first one part of sand and cement is poured, then the second and then the third part. Only after this addition of cement and sand can you add water to the concrete mixer, this is done gradually, where water is better than an ordinary watering can. To prepare such special concrete it usually takes 5-10 minutes and no more.

Pouring concrete, anti-frost additives

Concrete is poured only below the general cutting level, this is done quite carefully and as competently as possible. The width of the hole in such a pile is quite large, so you can easily pour concrete into it simply from a bucket; the concrete should not be too weak and not very thick. Pouring concrete should be done slowly and carefully. To fill one pile, 10 minutes and no more will be enough; there is no need to rush here.

The poured concrete then needs to be compacted slowly and effectively so that the air quickly escapes from the poured pile and reinforcement can be used. The reinforcement will be lowered directly into the hole filled with concrete; you need to make simple movements along the pile itself. Builders also often use compaction by lightly tapping the sides of screw piles with a hammer.

Now that the concrete has been poured and compacted, it should still settle, after which a small amount of water will appear on the surface of the pile. Next, this water is removed; for this purpose, it is necessary to fill the piles on top with cement or dry sand concrete, where backfilling is carried out only for the last 5-10 cm and no more. The cement will quickly absorb water and harden.

If the air temperature is positive, then sand concrete or cement is diluted simply with water, as is usually done. And if the temperature is negative, that is, the work is carried out in winter, then it is necessary to add special anti-frost additives to the mixture. Ideal and most simple option The additive will be regular table salt, finely ground.

Salt will prevent the water from freezing until the concrete hardens. Only salt must be used at temperatures of at least -5C, otherwise a specialized liquid additive must be used. If such additives are not used in winter, the pole may even burst. Additives are required only in the part of the pile located below the freezing level and no more.

Conclusion

Installing screw piles is a fairly simple and easy process; if everything was done correctly and competently, then this foundation will work for up to 150 years or even more. Installation of a screw pile must include proper deepening of the product and pouring of concrete.

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Slab- pile foundation in the fall - the main points when pouring

Which foundation to choose

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Quite often you can see the use of a pile foundation with a grillage.

It can have a grillage in the form of a tape (pile-tape) or a slab (slab-pile). In the first case, the grillage will connect adjacent piles, in the second case, all piles are connected to each other by one large monolithic slab.

As for piles, they can be different:

• Screw piles.
• Concrete piles.
• Reinforced concrete pillars.
• Brick pillars and others.

You can buy them on the building materials market, or make them yourself.

DIY foundation piles

Making piles with your own hands does not require a huge amount of time, but you will have to work hard. To do this, it is necessary to carry out preparatory work and prepare the necessary materials and tools:

• A drill with attachments for drilling a hole for piles of the required length and width.
• Roulette.
• Formwork material.

In the area where the piles will be placed, their number should be clearly determined and their location should be outlined. Afterwards, drilling of holes begins with a hand drill. To do this, the drill is installed in the right place and immersed into the ground with rotational movements.

Every 30 cm, the drill needs to be pulled out of the hole and shaken off nearby. If this is not done, then after 1 m a large layer of earth may stick to the drill, and it will no longer be possible to pull it out.

Drilling the well should continue to the required depth, gradually increasing it with nozzles. Then, when the depth is reached, you should put on the nozzle to expand the hole.

The next stage of pile production is the installation of formwork. It can be different in shape, but it is best to keep it round. The following can be used as formwork material:

• Sheet steel with fasteners.
• Metal profile.
• Polystyrene foam box.

The height of the formwork must be at least 20-25 cm above ground level.

Pile reinforcement

Reinforcement can occur in two options:

1. Using two rods of reinforcement 10 cm long above the concrete pouring, which are inserted at a distance of 10 cm from each other and welded with rods of the same diameter across. There should be two such structures, they are located opposite each other, and are welded across with rods, forming a square frame.
2. A more complex option, which will require several rods of reinforcement, which are welded together in rings. The distance between the rings is usually 15 cm. This is a more expensive reinforcement option.

Pouring concrete

When the frame is ready, it is lowered into the well and a concrete mixture of grade M500 is prepared. To prepare it you will need a dry cement mixture m500, washed gravel in the same volume, washed sand (twice the volume of cement) and water (half the volume of cement).

When the concrete is ready, it is poured into the pits of future piles, covered with plastic film and left in this form for 1 month.

After this time, when the concrete has acquired the necessary strength, the polyethylene is removed, the formwork is dismantled and you can begin to create a grillage in the form of a slab.

Crushed stone for the foundation of the fraction

In the case of using crushed stone for a cushion under the foundation, you can use medium fractions, about 25-60 mm. If you use crushed stone for concrete, you should take small fractions of 3x8.

Slab pile foundation

It is a pile foundation with a grillage in the form of a slab. Grillages can be divided depending on their location in relation to the ground. The most popular is the grillage, which is located at a level of 15 cm from the ground and is used only on heaving or swelling soils. To do this, it is necessary to make a sand and gravel cushion, on which formwork, reinforcement cage will be installed and concreting will take place.

Another type of grillage is a low grillage. It is buried up to 15 cm into the ground and has high strength and load-bearing capacity. Used on soils not subject to movement.

And the last type of grillage is the raised grillage. In this case, its base is on the ground. To do this, remove a 10-15 cm layer of soil and fill the surface with gravel, thereby creating an anti-heavy cushion.

The slab grillage is performed as follows:

1. The pile heads are cut down to the required size.
2. Clean the top layer of piles from various debris and dirt.
3. The formwork is being erected. Depending on which grillage will be used, it is necessary to make spacers.
4. If the formwork is removable, it is protected from contact with concrete.
5. Pour the concrete mixture.
6. Level the surface of the grillage and leave to dry for 1 month.

Is it possible to pour the foundation in the fall?

Many builders tend to think that the foundation should be poured only in the warm season, but today this stereotype has been broken. It is possible to do the foundation in the fall; to do this, you just need to follow one of the recommendations:

1. Adding antifreeze additives. They help concrete not to freeze at low temperatures.
2. Covering the foundation. At low temperatures, it is recommended to cover the fresh foundation with plastic film, sawdust, and insulation.
3. Electric heating using electrodes or a heat cable.
4. Creation of thermal formwork. This is the most expensive method, however, it is very effective.

In conclusion, I would like to note that the slab-pile foundation is very strong and has a high load-bearing capacity.

Based on materials from the site: http://fundament-help.com