Preserving the foundation before winter. Pile-grillage foundation How to leave a pile-grillage foundation for the winter

The construction of houses in recent times was carried out on four main types of foundations: slab, strip, pile and columnar. Typically, a strip foundation is made and buried below the freezing level of the soil. But the construction of this foundation is quite expensive, or rather almost half of the entire construction budget. Not everyone is ready for such incredible expenses.

The situation can be saved with the help of a new type of foundation - pile-grillage. Its appearance is very convenient, it is constructed in such a way that there is no need to remove the formwork from it later. This foundation is also excellent at supporting a building on uneven ground or slopes, unlike a type like a pile foundation for a house.

What is a grillage type pile foundation?

A pile foundation for a house is known, which consists of a certain number of piles that are buried in the ground. But the use of this foundation is not so popular due to the fact that it is not possible to redistribute the load of the structure between all the piles. Usually it is used only in the case of construction from timber or logs, since such material can itself redistribute the load. For others building materials he doesn't fit.

But there is this kind pile foundation, which is performed with a grillage. A grillage is a beam or slab with which piles are connected together on the surface of the earth. The grillage can be a monolithic or prefabricated monolithic structure, or prefabricated. Due to the fact that the piles are interconnected, the load is distributed evenly and the foundation can be used for block and brick buildings.

Different parts of the finished building have different loads, which are determined by the finishing, both internal and external, furniture and other contents of the house. The grillage is designed to take on such a load and distribute it among the piles.

This helps eliminate uneven shrinkage of the piles, which leads to cracks in the walls and their destruction. This does not exclude the main disadvantage of pile foundations - uncertainty about the type of soil that is located under each of the supports. It is simply impossible to predict the behavior of the foundation in advance, so architects do not particularly like this type of house foundation, since it does not guarantee long-term operation of the building.

Advantages and disadvantages of a pile-grillage foundation

The grillage type of pile foundation has pros and cons. Let's consider the advantages due to which this foundation is becoming increasingly popular:

A relatively simple installation technology that can be carried out by a small team of professional workers.
Thanks to the first advantage, construction costs are reduced.
Low consumption of concrete.
Since the foundation will not be in contact with frozen soil, the house will not lose heat.
The unique technology of connecting the grillage and piles prevents the house from vibrating even when located next to railroad tracks.
Work on installing such a foundation can be carried out at any time of the year, but not when the frost is below 10 degrees.
The construction of the foundation is not affected by the level groundwater.
This foundation, as mentioned earlier, is perfect for construction in areas with heterogeneous terrain.
There is no need to prepare the site in advance, for example, to remove the fertile layer or grass, which significantly saves construction time.
The cost of work, which depends only on the material used.

Like any technology, the equipment of a pile-grillage foundation also has its negative features:

It is not possible to create a basement in the house or ground floor. If this is provided, it will require large financial costs.
Not suitable for houses weighing more than 5 tons.
A clear calculation of the number of piles and the expected load in accordance with the type of soil is required. You also need to clearly know at what distance and at what depth to install the piles.
It is mandatory to follow the reinforcement density in accordance with the brand of concrete used.
It is possible for piles to rupture when frozen soil puts pressure on them, but such cases are extremely rare.
There is no grillage waterproofing.
It is necessary to use special equipment, which will entail additional costs.

Important! A pile foundation for a house with a grillage is perfect for small houses or baths, and not for massive buildings with several floors.

Preparatory work before construction

Before carrying out work on installing such a foundation with piles, it is necessary to prepare everything necessary tools and materials so that there are no unpleasant pauses during the construction process.

Selection of piles and their location

For such a foundation you need to take care making the right choice piles in use. Depending on the material of the piles, you can choose concrete, metal, wood or reinforced concrete. They can also be hanging, that is, those that transfer the load from the building to the side surfaces. There are piles in the form of racks that directly load the soil that is located under them.

Typically, when constructing a pile foundation, cast-in-place piles are used, which are placed in holes prepared for them directly at the site where the foundation is installed. You can also fill so-called injection piles, which are made by pouring concrete into a hole with reinforcement in the middle. The use of cast-in-place piles, which are simply driven into the required place using special construction equipment, is also ideal.

Piles can have different sections: square or triangular, as well as round in a hollow or filled design.

Important! Such a foundation can save use by 1 cubic meter. meter 100 kg of high grade cement, and also reduces excavation work by 3 cubic meters. m and reduces labor costs.

In this type of foundation, there are five ways to decompose piles in the ground:

Single - the location of the piles relative to the support, each under its own. In some cases, piles are installed obliquely, this is due to the characteristics of the terrain.
Tape - arrangement of piles along the entire perimeter of the building.
Stripes - used for massive buildings with several floors. This is the installation of piles in several rows.
In the form of bushes, piles are located where a large load is expected and under load-bearing walls. Also, this method of arranging piles is used in the construction of canopies in places where columns holding the roof are located.
Field - arrangement of piles in a checkerboard pattern under the entire grillage, which is large in size.

In order to correctly calculate the number and location of piles for building a house, you need to take into account certain rules. First of all, there must be a detailed plan of the building, in accordance with which the calculation will be made. Piles must be in the corners, as well as in those places where the walls intersect. If there is a distance between them that is more than three meters, then the installation of intermediate piles is mandatory. In general, the most optimal distance between piles is 2 - 3 meters. There should be no problems with this stage, but you will need to think about calculating the area of the pile.

To create a reliable foundation for a house with a grillage-type pile foundation, it is necessary to make certain calculations. In this case, the following indicators must be taken into account:

The mass of the house itself and its internal components.
Support area that is required. It is calculated in relation to weight and safety factor.
Sectional area of piles. To do this, their number is multiplied by the area that is selected. The result obtained will be the total area of the piles.
If the total area of the piles obtained in the previous paragraph is greater than that required, its calculation was carried out in paragraph 2, then all parameters are correct and they are suitable for this structure.
If the total area is smaller, then it is necessary to increase the cross-section and recalculate. Thus, we find the required number.

Sometimes situations arise when it is easier to increase the number of piles rather than their cross-section. In this case, the method by which the calculation was made does not change. The area of support that is needed to create a reliable foundation can be calculated using the following formula:

The support area is equal to the mass of the house multiplied by 1.4 and divided by the bearing capacity of the soil.

The soil bearing capacity indicator should be taken from the table presented:

The use of a coefficient of 1.4 is explained by the fact that it is not known what kind of soil is located under each pile, so it is better to play it safe and take a little more.

Step-by-step technology for installing a pile-grillage foundation

After all the work related to the calculations has been completed, you can safely proceed to the main stages of foundation construction.

Marking the construction site

It is best to remove the fertile layer of soil and take it out onto the plot or into the garden. Then it will be necessary to level the top surface. Using pegs and a cord, you need to determine the boundaries of the house. At this stage, not only external, but also internal wall boundaries must be outlined.

Important! It is better to check the geometry by repeated measurements and pulling the cord diagonally.

After the marking has been made, it is necessary to mark the places where the piles will be installed in accordance with the plan drawn up earlier.

Carrying out excavation work

In order to decide on the work on the ground that will be carried out, you need to clearly know which piles will be used. A house on a pile foundation of a grillage type is usually placed on screw or bored piles. Screw-type piles can be screwed in with your own hands, but only at one level, which is marked in advance by pulling the cord.

Bored piles require the use of special equipment. With its help, you need to drill holes in the ground in marked places. Formwork is installed in these holes, and reinforcement is also made. Usually these are 4 pieces of ribbed reinforcement that are connected to each other. Next, the last step is to pour concrete into the prepared holes.

Important! It is imperative that after pouring, the ends of the reinforcement, about 60 cm long, must remain outside, and some must be 20 centimeters longer than the first.

Grillage arrangement

When choosing a metal structure, the grillage must be welded strictly horizontally to the ends of the reinforcement bars.

In order to make a reinforced concrete grillage of a recessed type, you need to backfill it with crushed stone. To improve the quality of the foundation, crushed stone is poured in layers of 5 cm and each layer is processed with a vibrating platform. This must be repeated until the layer reaches the desired thickness, at least 15 cm.

Formwork is installed on the finished bedding. It should be slightly wider than the width of the walls, and the height depends on how high the base is intended. The installation of the support and the assembly of the panels is carried out using the technology of installing a strip foundation. Typically, boards nailed together or waterproof plywood are used for formwork. Each type of grillage has its own nuances of formwork construction, but the main thing remains that the formwork must be 5-10 cm higher than the height of the finished grillage.

Important! Work should only be carried out using a level.

The foundation is reinforced in the same way as when installing a strip foundation. That is, at the top and bottom there are two belts of ribbed reinforcement, connected to each other by rods of a smaller cross-section and a smooth surface. You only need to add a dressing with piles. The pieces of reinforcement coming out of the piles must be bent and one row tied at the bottom to the reinforced belt, and the second at the top.

In order to avoid wasting time and nerves on pouring piles, you can purchase ready-made ones made of reinforced concrete.

Installation of additional elements and pouring concrete

This stage involves the laying of special pipes through which in the future it will be necessary to carry out communications such as heating, sewerage, water supply and others. Ventilation holes in the foundation are also required.

If this stage is skipped, then the integrity of the grillage will definitely have to be violated, which is extremely undesirable and generally unacceptable for such a foundation.

To start concreting, you need to make the mixture yourself. A particularly high-quality solution will be obtained from the M200 or M500 cement brand. It must be diluted according to all the rules and mixed thoroughly.

Concrete is poured, but it must be processed with a vibrator. Be sure to pour the entire mixture at one time to avoid layering. The top layer must be leveled using a rule and checked for horizontalness using a level. The top layer of concrete is covered with a film to prevent it from drying out and causing cracks on the surface. If the weather is hot outside while the concrete poured into the foundation is drying, then the top layer must be moistened.

After pouring, the formwork can be removed after a certain period of time:

If during the work of pouring concrete and the following days the air temperature did not drop below +20 degrees, then after 4 days the formwork can be removed. Under such conditions, the foundation and piles will gain more than half the strength, which will make it possible to use them for subsequent work.
If after pouring the temperature was around +10 degrees, then you will have to wait 14 days before removing the formwork panels.
At temperatures below +10 degrees, freezing conditions are already considered winter, and additional heating and insulation of the foundation will be required.

Before carrying out work on the installation of a pile-grillage foundation, it is imperative to familiarize yourself with SNiP 2.02.03 - 85. This document officially spells out the requirements for the arrangement of this type of foundation, tolerances, calculation by coefficients, and pile materials. Also here you can find recommendations for construction on normal soils, as well as in areas that have suffered from landslides and karst. Pile foundations are fully regulated by SNiP.

Possible mistakes when arranging the foundation

Often, those who do not have experience in laying this type of foundation make many mistakes, which are subsequently very difficult or even impossible to correct. This:

If errors are made during the calculation process, the foundation will go underground, and it is very difficult to slow down this process, and in some cases it is not at all possible.

Conclusion

Pile-grillage foundation is a combination quality characteristics pile and strip type in one base. It is perfect for those buildings that are not very heavy, and will distribute the load evenly between all piles to prevent cracking of the walls. The grillage will be more reliable and of better quality than a conventional pile foundation and will help to close it, and also more economical than building a strip foundation. It will be very difficult to complete such a foundation on your own, so you will definitely need the help of a professional who will correctly make all the calculations and help with the construction of the structure.

Typically, preservation of the foundation for the winter is used when the budget is insufficient, when it is not possible to pour the foundation, install walls and roof in one season. At the same time, it is necessary to protect underground reinforced concrete structures that remain without load from wetting and heaving forces. This requires waterproofing of concrete surfaces, insulation of the soil adjacent to the foundation, drainage at the level of the base of the tape or slab in accordance with VSN 29-85.

Piles of hanging grillages need not be insulated; columnar foundations can be left without vertical loading on cold period strictly prohibited.

The decision to pour the foundation in winter is quite justified, since it allows the construction of walls to begin in early spring in order to guarantee that the home will be occupied in the same season. The main problems of “freezing” construction at the stage zero cycle are:

absence of loads from the weight of power structures to compensate for frost heaving of soils;
opening of cracks from frozen water inside the structure of wet concrete;
deformations, ruptures, tilting of reinforced concrete structures caused by swelling of clay soils.

The occurrence of heaving forces is possible only in the presence of three factors: a high clay content in the soil, the presence of moisture for its swelling, freezing to increase the volume of the soil by 9 - 12%. By removing any component, swelling can be reduced or eliminated completely.

Thus, in order to preserve an object with a monolithic foundation, it is necessary to insulate the perimeter of the building, protect concrete and soil from moisture, and replace heaving soils with non-metallic material.

The need to freeze construction

Suspension of work is not always caused by a lack of budget. Many individual developers prefer not to take risks, leaving the masonry until the next season. For wooden cottages There is no particular point in freezing the object - the technologies of panel, log, frame, half-timbered and panel construction are all-season.

To leave a concrete underground structure to winter, it is necessary to complete all foundation work:

drainage - wells in the corners of the building, corrugated pipes perforated with slots between them in a double geotextile winding;
underlying layer under the sole - drainage + leveling of the site + elimination of swelling;
waterproofing - carpet under the sole (2 - 3 layers of Bicrost, polyethylene film, for slab foundations) + fusing of rolled bitumen materials on the side and top edges, coating with mastics, treatment with penetrating compounds or plastering with moisture-resistant mixtures;
insulation – horizontally laid extruded polystyrene foam EPS under the blind area at a depth of 30 – 40 cm + gluing the outer surface of the foundation with the same material;
backfilling - non-metallic material must cover the surfaces of the foundation with a minimum of 20 cm layer compacted with a vibrating plate.

underground reservoir drainage system must have a minimum distance of 4 m from concrete structures and be located below the base of the MZLF. The collected waste water can be reused.

Important: Each wintering of the foundation without a waterproofing coating reduces its strength and resource by 20%, that is, after 5 years you can destroy the MZLF or floating slab and build them again. Under no circumstances should you buy plots with such foundations.

After that, it remains to protect concrete structures that remain without load from lateral freezing and swelling of adjacent soils. To reduce costs, you can use natural insulation - snow, organizing the detention with shields.

Foundation protection measures

The best option for preserving the foundation in winter is to pour a floating slab, waterproof the surfaces of concrete structures and insulate the blind area. Even if there is uneven swelling after the soil thaws at the beginning of the next season, nothing can happen to the slab. It is much more difficult to maintain a strip foundation:

water is collected in the grille of the structure;
uneven swelling exerts twisting, pulling and bending forces on the belt without load.

Therefore, before leaving a strip foundation in the winter, it is necessary to carry out the following operations:

strip the tape - wooden panels will not be able to protect the structure, they will swell from precipitation, serve as a wet compress, and contribute to waterlogging of the concrete, which is very dangerous when frozen;
waterproof surfaces - by gluing, coating, plastering or penetrating compounds;
make drainage - if this was not done at the stage of the underlying layer;
insulating the blind area is the final part of the standard MZLF technology.

Despite the complex of work carried out, it is difficult to keep the foundation intact, since the building itself and heating of the interior are missing. Thermal insulation of blind areas in “unfinished buildings” turns out to be little effective; there are options for additional protection against moisture and freezing:

perimeter cultivation - you can plow the soil around the foundation, harrow it to break up large lumps;
snow insulation - installation of panels for snow retention (Given the nature of recent winters in the central part of Russia, with large temperature differences from plus to minus, such insulation can only do harm. Therefore, it all depends on the construction area. Snow should lie all winter.);
“hut” - foundation elements are covered with natural insulation and plastic film;

Aeration of the soil allows the density to be reduced, after which water saturation automatically increases; when freezing, swelling is practically absent. Natural insulation materials are: bark, straw, shavings, slag, sawdust. Insulation prepared for roofing (expanded polystyrene, basalt wool), partitions and walls can be used, which can be reused.

After pouring the strip foundation, numerous pools are obtained in which sediment accumulates. In principle, it will not be possible to cover the entire perimeter with films - this material will be located horizontally and will not withstand the snow cover. Therefore, the boards covered with film are leaned against the tapes at an angle on both sides. Conservation measures in winter are described in departmental standards VSN 29-85.

In fact, the MZLF of a cottage that remains in winter is as similar as possible to the foundation of any unheated (seasonal) building. To compensate for the heaving forces of underground reinforced concrete structures of unheated houses, the following scheme is used:

a horizontal 5 cm layer of high-density extruded polystyrene XPS foam under the entire building base;
insulation of a blind area 0.6 - 1.2 m wide with sheets 5 cm thick;
increasing the thickness of the heat insulator under the blind area in the corners by up to 10 cm.

Another method is less commonly used, when the heat insulation is laid under the floors on the ground, continues vertically along the inner edges of the MZLF tape, the insulation of the blind area is not connected to the internal heat-insulating contour.

However, if the foundation of a cottage intended for permanent residence is being preserved, it is irrational to spend such an amount of insulation by burying it in the ground. Therefore, the top layer of soil is covered and measures are provided to drain rain and melt water. The blind area is usually poured and decorated at the stage of finishing the facades; during conservation in the ground, improvised trenches with a slope can be made to drain surface moisture.

If the construction site is frozen for several seasons, the zero-cycle facility must be reopened with the onset of spring. This will allow moisture to evaporate naturally and dry the structural elements. For the next wintering, the foundation is prepared using the above technology. The blind area is concreted in winter only after a full range of work has been completed:

a drainage system must be installed;
engineering systems were introduced into the building;
extend the grounding loop;
waterproofing of all concrete surfaces was carried out;
vertical + horizontal insulation has been completed;
backfilling was made with non-metallic material.

Otherwise, next season the trenches will have to be excavated again to carry out the above work. Decoration of blind areas with paving stones, rubber, PVC tiles is carried out after completion finishing works so as not to damage the coating.

Thus, the foundation of the home can be left without load in the winter, providing the specified protection measures. The main tasks are to preserve the geothermal heat of the subsoil with heat insulators and to prevent the concrete and adjacent soils from getting wet. Subject to modern foundation construction technologies, 90% of work is performed by default.

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Pile-grillage foundations are deservedly popular among many private developers, because they are specially designed for small compact buildings of brick, block or wooden construction. But such buildings cannot have a basement as such, perhaps a technical underground floor, but this drawback is completely offset by the expanded scope of application. After all, foundations can be built on sandy and loamy soils that are prone to small movements. At the moment, reinforced concrete pillars with SS strapping beams are a little more expensive only for slotted reinforced concrete monoliths.

Therefore, the key argument in favor of such a base is its low cost and speed of installation.

Which grillage to choose: hanging or monolithic

It all depends on the design of the building itself. After all, 70 piles with a maximum diameter of 50 cm are enough for a light house with a load-bearing capacity of up to 5 tons. If more is needed, then the diameter of the pile only increases. The pile-grillage foundation is stable on heaving soil, because the piles are resistant even to severe frosts. There are two options for this basis:

Hanging base. It has its pros and cons and differs in design. In such a foundation there is an open air gap between the grillage and the soil surface, so there is no direct contact with the ground. But at the same time, such a base has a key disadvantage - it is the need to waterproof and thermally insulate the lower edge of the grillage surface. After all, this is, in fact, the floor of the building and heat leaks through it. This budget option, but due to its technical complexity it is quite rare.
Monolithic grillage foundation. Formwork is used here, which forms an even concrete frame. Considering that during the construction process a monolithic reinforced concrete slab, then to level the height of the platform, concrete piles of various lengths are used, and the immersion depth often remains the same. The key disadvantage is high-quality reinforcement with further welding of all connecting elements, as well as the implementation of a sand cushion. Such a foundation comes into contact with the soil through its structure.

The key element of such a foundation is piles. They are made from concrete, reinforced concrete, steel or wood, and are round or rectangular in shape. The material is selected depending on the type of soil and the severity of the future structure. Each type of pile has its pros and cons, but given that pile-grillage foundations are calculated individually in each case, it is not difficult to choose the optimal solution from a budgetary point of view.

The second element of the base is the grillage. This is a monolithic reinforced concrete structure, on the surface of which load-bearing walls are erected. Its main purpose is uniform distribution weight of the structure for each pile separately.

The combination of piles and grillage makes the load-bearing foundation more stable and reliable.

Advantages of pile-grillage foundations

Disadvantages of such foundations

There are also disadvantages to such foundations, as well as advantages; they must be taken into account when designing foundations:

It is necessary to carry out careful preliminary calculations of the load on the load-bearing elements of the building. And this can only be done by qualified specialists with experience in this field.
A detailed working documentation, where all piles, their length and diameter, as well as the installation location are taken into account with an accuracy of a few centimeters.
It cannot be used for massive and heavy structures, because it has a small maximum load. And it can be increased solely by increasing the diameter of the piles, but even such actions will be ineffective.
Considering that the design provides for the presence of free space between the floor and the surface, it is necessary to insulate the structure. And these are additional labor and financial costs.
There are some difficulties when repairing existing foundations; here you have to build or retaining walls, or install additional piles, which is very difficult to do.

For a number of reasons, construction work in the private sector are suspended in the autumn-winter period. If you have already poured the foundation in the summer or are just going to do it, hoping to leave it until winter, you need to study the features of this technology.

Good conditions for the formation of high-quality concrete are a temperature of 18-20 degrees and humidity slightly above average. This weather in our climate lasts until September. And if the concrete does not set before frost, then destruction of its monolithic structure will inevitably occur due to the expansion of water, which has turned into ice.

If you meet such a deadline, then already in the process of building the foundation, you need to take a number of measures so that in winter it does not collapse under the influence of external environment. Preserving the foundation for the winter is to protect as much as possible construction site from rain, snow and groundwater. Besides, reinforced concrete structures without load, they can be pushed out from the swelling of unevenly frozen ground.

Already at the stage of excavation and formwork you need to take care of drainage, insulation and waterproofing. Hanging piles from grillages may not need to be insulated. But separate pillars, left unloaded for the winter, will definitely move in different directions. Any monolithic foundation exposed to the forces of earth heaving. These processes are especially noticeable in clayey, moist and deeply frozen soil. If you get rid of the influence of at least one of these components, the deformations can be significantly reduced. We need to seal off the space surrounding the foundation from moisture, insulate the concrete, and pour sand, screenings, or other non-metallic compounds into the larger pit.

Scheme for the removal of ground waters to the contents Preservation of the foundation for the winter

For safe wintering of the foundation, its construction must be completely completed. Here are the main steps:

Make a double geotextile wrapping of perforated pipes in drainage wells.
Before pouring, build drainage and bedding under the leveled area.
Dig a well to drain drainage water. It must be deeper than the base of the foundation and located no closer than 4 meters from the construction site.
Lay roofing material or special foundation films in several layers under the foundation.
Fuse a Bikrost-like material onto the walls and top edges. Carefully cover all cracks with mastic or plaster open surfaces with a moisture-resistant mixture.
At a depth of 30-40 cm, lay hard foam plastic under the blind area. They also cover the outer surfaces.
Sand or crushed stone is poured into the space around the formwork and on top in a layer of 20 cm. It is advisable to compact it using a vibrating plate.

Since snow is a good natural insulator, you can install wooden slabs vertically - they will retain the snow. But if winters in your region are associated with thaws, the disadvantages of such work may outweigh its advantages.

Whether it is possible to leave the foundation for the winter also depends on the type monolithic design. The slab, if waterproofed and insulated, usually easily tolerates all uneven deformations of the soil. With tape everything is much more complicated. The area between the ribbons becomes the “pool”. The tape itself warps and twists due to swelling of the soil. Therefore, a number of additional actions need to be taken with the strip foundation:

Disassemble the formwork around the tape. Swollen boards only contribute to waterlogging of the concrete.
Cover and seal all surfaces with waterproofing.
Insulate the blind area with polystyrene foam.

Due to the fact that there is no house yet, there is no heat source and peripheral thermal insulation is ineffective.

Without thermal insulation it is impossible to preserve the structure

Here are some more tips on how to protect your foundation from moisture and low temperatures in the winter:

Place straw, spruce branches, branches or sawdust on top of the tape, and cover the top with film.
Plow and harrow the ground. Loose soil is a good heat insulator and concentrates more water without letting it pass into the depths.
Install snow-retaining boards from boards. This will have a positive effect if the snow does not melt during the winter.
It will not be possible to protect the space between the tapes from water. Therefore, film-covered wooden slabs are installed with a slope on all sides of the tape.

A foundation without a building, left for the winter, can be compared with the foundation of unheated buildings. And for them, a 5 cm layer of polystyrene foam is used under the entire foundation, the blind area is insulated with the same material to a width of about a meter, and a layer of 10 cm is placed at the corners of the blind area.

Insulation of slab foundations

Of course, if the house is designed for further year-round accommodation, it is not economically feasible to spend so much heat insulation on the foundation. Therefore, the main thing is to ensure high-quality thermal insulation and drainage of groundwater. The blind area is done after finishing the walls.

If construction cannot be continued next season, the facility will still be re-opened in the spring so that the concrete dries completely during the warmer months. In the fall, the quality of waterproofing and the operation of the drainage system are checked. All violations are corrected and closed again for the winter.

It is estimated that a foundation that has stood for one season without being closed loses up to 20% of its strength. Thus, if it stands open for 5 years, it will become completely unsuitable for building a house.

A few words about the foundation of a house already built in winter. High humidity is present in any structure located near the surface of the earth. A strip foundation that is well insulated and drained still accumulates excess moisture because it is not heated, but it maintains a positive temperature in winter. This makes them rot wooden beams, and dampens the concrete.

To solve this problem, vents are made in the foundation strips. They are located above the snow level. Ventilation also saves from the accumulation of radon gas in the basement. Excess radon can lead to radioactive contamination of the entire home.

Many people try to protect the basement from freezing by covering the vents with various heat insulators. You shouldn't do this. The drier the air in the underground, the better the basement retains heat. This means there will be a good microclimate on all floors.

We recommend watching a video on how to close the foundation for the winter

A good foundation is the basis of a comfortable home.

Artyom:
The use of monolithic slab foundations in low-rise construction economically completely unjustified.

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Justified if it's like a Swedish stove.
Atos:
interesting association. What will happen to this float if the swelling is not uniform? And that’s exactly what it will be

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Pathfinder: is it worth spending extra money on a “serious foundation frame” where you can do without it??
In the absence of walls and roof, the blind area does not affect anything in any way.
But it affects the walls and roof.
Artyom:
When the soil freezes and swells, in the case of using a pile foundation left without load for the winter, the destruction of the grillage is almost inevitable, because “each pile walks in its own way.” The exception is the southern regions of the Russian Federation, where the depth of winter freezing is ridiculous and the use of a pile foundation is simply economically unjustified for private buildings of up to 5 floors. It is the uneven “walking” of the piles relative to each other, during freezing, that causes the destruction of the grillage

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Piles do not move at all if they are made correctly. In TISE, the calculation takes into account failed piles, that is, those that ended up in the wrong place.
Artyom:
Pathfinder: is it worth spending extra money on a “serious foundation frame” where you can do without it?

Click to expand...

Whether it's superfluous or not is another question. Depends on a lot.
Pathfinder:
If the foundation frame is serious, then nothing will happen. In addition, you are missing out on the insulated blind area.

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A serious foundation frame + insulation of the blind area can make such a structure unreasonably expensive.
Artyom:
Uneven freezing of the soil, as well as its swelling, when using a strip foundation, will lead precisely to the float effect. Those. any changes due to changes in weather conditions in an unloaded state will be COMPENSATED WITHOUT CHANGES (appearance of cracks). Of course, even with its full load (“under the roof”), next season, provided that the foundation is correctly calculated.

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But the men don’t know - they bury the tape on heaving soils below the freezing level. Naive - they think that such a float will not be enough for a long time

And what is characteristic is that experience shows them to be right.

Artyom: When the soil freezes and swells, in the case of using a pile foundation left without load for the winter, the destruction of the grillage is almost inevitable, because “each pile walks in its own way.” The exception is the southern regions of the Russian Federation, where the depth of winter freezing is ridiculous and the use of a pile foundation is simply economically unjustified for private buildings of up to 5 floors. It is the uneven “walking” of the piles relative to each other, during freezing, that causes the destruction of the grillage.

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No amount of heaving will stop the correct pile from moving. Are you confusing piles with pillars?
Alik, if you are planning to fill the foundation this year, in addition to covering it with film or bitumen, also treat it with a water repellent. It will protect the structure from moisture, preserving it until the new construction season. The choice is yours.
Thanks to everyone who responded! I have already decided to do nothing this year, but rather spend time on
- complete preparation of the territory for construction
- geology and geodesy
- detailed study of the construction plan for all communications, study of the equipment market, search for suppliers...
I think this will help me reduce construction time and costs no less than the race with pouring concrete...
Piles LEFT WITHOUT LOAD, driven to any depth, are subject to swelling, which results in the destruction of the grillage. Read more carefully.
To the Pathfinder: Everything is determined by expediency and the availability of money. You can heat the house with gas or wood, but you offer it in banknotes. If you like it, heat it.
If I'm not mistaken, the initial hardness of concrete takes 20-30 days (professionals will correct it), the final hardness takes a lifetime.
You can pour it at any time, only in winter you will have to pour it with additives and warm up the stove (they don’t stop building houses in winter)
It’s economical to do this now. from the main +,
1. You have money for this.
2. The work is now cheaper than it will be in the spring, but only God knows what will happen in the spring.
3. Before winter it will acquire the necessary hardness.
4. save time in the spring.
5. As always, they scare us with a crisis.
I would now fill the stove and go away for the winter.
Artyom:
Atos: That’s it, it’s clear that they either don’t know about strip foundations(and their properties), made on a sand and gravel bed, or they have nowhere to put the money. In the region of the Republic of Kazakhstan, such foundations are used everywhere for heaving soils with freezing up to 1.98 m.

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They use it, then they use it, and then they always repair the cracks in the houses.

Artyom: Piles LEFT WITHOUT LOAD, driven to any depth, are subject to swelling, which results in the destruction of the grillage. Read more carefully.

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You should be more careful - we are not talking about driven-in hanging piles, but about ones that are cast in with an expansion at the bottom - see the picture - such piles don’t care about heaving
There is still mud in the spring, increased level groundwater.

7 years ago

Svarog (Builderclub expert)

Mm... I followed the chain of questions as best I could, my thoughts on this matter:

1. It is quite possible to leave the foundation unloaded for the winter, the fact is that if you are going to fight heaving with a weight, then this is not a rewarding task, you will lose in advance. Understand that these are efforts of the order that raises multi-story reinforced concrete. at home and you're talking about small house(sauna, etc.). You have clay and most likely the soil is heaving, so let’s try to remove the influence of this scourge, rather than fight the consequences. The TISE drill, if it really performs this action “a natural expansion is formed below, in the shape of a truncated cone,” forces the lower part of the pile to be pulled down when frozen, while, top part pushes out frozen soil (the main thing here is that the pile does not break, this really can happen). I would suggest that you isolate the part of the pile above the heel from the ground, for example with greenhouse film or roofing felt. The same can be done when constructing a bored pile (your reinforced concrete pile in a drilled well is correctly called) without an expanding slab. In general, it is better to place the heel of the pile below the freezing level of the soil, and calculate the pile without taking into account lateral friction. I recommend insulating the foundation for the winter (just cover it with snow - that’s enough). The fact is that the pile is made of reinforced concrete, and it, in turn, conducts heat very well, and until it is covered from above by a building, it will freeze around the pile to a greater depth than seasonal freezing. To determine the freezing depth you need to know where you are building...

2. The concrete belt (called a grillage) does not have to be made so high and not necessarily the entire width of the pile - it is only necessary to make the reinforcement outlets narrower and maintain a protective layer. In general, everything needs to be done according to calculation :) i.e. its dimensions should be made according to strength calculations with some margin due to the low quality of unprofessional work.

3. The heel shown in the Valera figure will not affect the pulling out, since it is not connected in any way with the pile, and its structure is indeed vague :). Such a heel can only increase the load-bearing capacity of the pile.

4. There is no need to deepen the grillage, usually this is done only for reasons of manufacturability of the installation of piles (drilled a well and filled it with concrete), there is no need to make formwork until required height. No one has addressed the issue related to heaving soil on the impact on the grillage. Even if your pile doesn’t lift, your grillage can lift – the result is the same for construction :). To prevent this from happening, it is necessary to leave a gap of 50-100mm under the grillage. The gap can be dug after using a grillage to reach 70% of the strength (it’s better to wait for 100% - 28 days), and make sure that the soil does not fall back in. Or you can fill the grillage over a base made of expanded polystyrene with a thickness of 50-100mm, this will solve 2 problems - you won’t need to make gravy under the grillage - the expanded polystyrene will hold water, and you won’t need to make a gap - if necessary, the soil will crush it, but the grillage will not be affected.