Is it possible to fill the foundation in winter - features of the work. How to pour a foundation in winter: we will learn from practical actions how to pour a foundation in winter. Is a foundation made in winter?

The temptation to pour a foundation in winter is incredibly strong. Building materials for the foundation, as well as labor, are much cheaper at this time than in the summer, and any person has much more free time.

However, many people are afraid to start construction in the cold season, since there are a number of concerns that are associated with possible destruction of the structure, poor hardening of solutions, as well as preliminary wear and tear of some building materials.

Pouring a foundation during frost is a truly labor-intensive and complex process, but at the same time, it is possible to implement. Those wishing to start construction in winter should be prepared to work in conditions of low air temperatures and carefully select technologies and materials.

Pros and cons of winter foundation pouring

Advantages

• Pouring the foundation in winter is justified when the building plot has very “fragile” soil. Frozen soil retains its shape well, so work here is usually carried out in winter.
• Pouring the foundation in the cold season is justified by construction in the northern regions.
• Low price of building materials and labor.
• In winter, people have more free time.

Flaws

• If workers can dig a trench under the foundation in the summer, then in winter it will be necessary to use special equipment to cope with the frozen ground.
• There is a risk of buying low-quality materials that suppliers have not been able to sell for a long time.
• Work in fairly harsh conditions.

Features of winter filling

To ensure the reliability and strength of the foundation of a country house when pouring it in winter, certain rules must be followed. First of all, you cannot carry out work in parts with very long periods of time between each individual pour. The concrete solution is laid in small segments, quickly covering them with the next layer. You also need:

• It is good to clear the prepared trench of snow and remove any ice that has formed from the bottom of the ditch and the reinforcement.
• Cover the pit with special insulating material.
• Warm up the bottom between all the walls of the formwork in advance.
• Provide full access to the formwork.

It is impossible to pour concrete on top of frozen soil, since when it thaws it will settle and may well become the main cause of subsidence of the foundation.

Pouring the foundation depending on its type

• Strip foundation. This option is the most popular among developers. The disadvantage of pouring the foundation in winter is low labor productivity. Workers need to rest more often, and some operations require much more time than in the summer. Experts advise, as far as possible, to reduce the number of “wet” operations. For example, the use of ready-made concrete blocks. They are delivered directly from the factory and placed in a finished pit. For the blocks you will need just a little bit of concrete mortar, which means a significant reduction in “wet” work.
• Ready-made concrete piles. If the planned building is lightweight, then you can use pile technology. This type of foundation is very popular among timber houses. By following the rules of construction, you can build a reliable and durable pile foundation in winter, which will not be inferior to other types of bases. Concrete piles are divided into two categories: bored and drilled. The first ones are made by pouring concrete into drilled wells, while drilling ones are driven into the ground. The second category is much faster and more convenient, since piles can be purchased from the factory without having to make a solution. But the disadvantage of these piles is their price and a lot of noise at the moment of driving the piles into the ground. The solution to the problem is the use of screw pile technology. Today this technology is very widespread and popular in the construction market.

How to pour a foundation in winter?

Algorithm for pouring a foundation with concrete in winter:

• Excavation. Digging in winter is difficult, so we use an excavator.
• Formwork. This is done in the same way as in the summer. Shields are assembled from boards 20 mm thick and supported with special spacers.
• Mixing concrete. First you need to mix water with an additive and a plasticizer so that it does not freeze. Then add crushed stone and sand. Proportion 1:3.
• Filling. Before pouring the foundation in winter, it is advisable to choose a day without wind or precipitation.
• Insulation. We cover everything on top with polystyrene foam and press it down with bricks so that frost does not hit the cement. Very low temperatures can easily damage the top layer. In severe frosts down to -20C, uncured concrete is completely safe. More than -20C is dangerous, you need to withstand it until this time for at least one or two months.
• Waterproofing. If spring waters are just around the corner and the concrete has not hardened, it is necessary to isolate it from water in any way. Inside the pit, you can dig a hole to collect sediment, and then pump out all the water, you can spray bitumen, and bolt the roll waterproofing.

Not so long ago, with the onset of frost, construction was also adopted to “freeze” in our latitudes. Moreover, no one undertook to start it. There could be no talk about the construction of concrete foundations and reinforced analogues if the thermometer warned of a drop below +5º C during the daytime, and at night stated negative temperatures. However, the length of the winter breaks in construction forced residents of the northern country to look for methods that would allow them to continue concrete work in the cold. This is how methods have emerged through which a durable monolithic foundation can be built at low temperatures. Having figured out how to pour a foundation during a difficult frosty period, you can safely begin building a bathhouse in winter.

The nuances of concreting in winter

It is not for nothing that winter was considered not the best period, both for pouring a monolithic structure and for constructing supporting elements of bored and pile types of foundations. The reason for this is the crystallization of water, one of the main components of the concrete solution. By turning into ice, water not only interferes with the normal course of the hydration process of the concrete mixture - that is, the formation of reliable molecular bonds due to its work. Due to the formation of ice crystals, the dimensions of which increase the initial volume of water by 10%, porosity increases. This fact in no way contributes to obtaining the planned strength of the foundation, but significantly reduces it.

Let's understand the mechanism of hydration

Concreting is the process of gradual transition of a mixture of cement with sand and crushed stone from the liquid phase into the solid stone state assigned to it by rank. At a temperature background of + 15º and at a humidity level favorable for setting, the following occurs:

• first, a kind of sodium hydrosilicate shell is formed on the surface of the poured structure;
• then the upper layers of the poured mass are involved in the reaction - the hard grains of cement gradually suck out the moisture, due to which the components of the solution “stick together”;
• then the outer shell, losing evaporating water, begins to shrink;
• then deeper layers react;
• and further in the same sequence until after 28 days the concrete structure gains maximum strength.

If the foundation has to harden on a hot, dry day, the rate of hydration increases. But the water also begins to evaporate more actively, leaving in its place pores unfilled with bound concrete. At low temperatures, the reaction slows down, but pores appear due to the formation of ice crystals. To avoid this, the foundation is poured in winter according to special rules that make it possible to obtain the temperature of the solution required for normal hardening inside the poured concrete mass or individual pillars.

Hydration is accompanied by a spontaneous increase in temperature. The greater the thickness and dimensions of the concrete structure, the more heat the concrete generates and the slower it cools. Therefore, you should not get carried away with pouring support pillars in cold weather; it is advisable to prefer tape or monolith. If you install heat-saving formwork from insulating mats or slabs around massive structures, with minor drops in temperature you can do without additional tricks.

Classification and analysis of concreting methods

Owners, puzzled by the problem of whether it is possible to fill the foundation in winter, receive a clear affirmative answer, but with many variations. Options for solving the problem of maintaining or creating the conditions necessary for normal hydration depend on:

• on the dimensions of the structure;
• on the chemical composition of the concrete mixture and on the proportions of the components;
• on the brand of binder cement and the fineness of its grinding;
• from climatic nuances;
• from the ability to heat water and filler.

Often the heat released during hydration is not enough to create the conditions necessary for concrete during the frosty period. Finely grinding the cement helps to slightly increase the temperature, due to which it reacts faster and releases more heat when combined with water. Heating the water and aggregate before mixing also helps.

Attention. Only water and fillers can be heated. Cement cannot be heated, otherwise it will lose its binding properties.

Usually in our latitudes, for winter pouring, a solution with a temperature above 21º C is not used, given that when moving from a concrete mixer to a place, it will release 4.5-5º C to the atmosphere. To obtain the working temperature of concrete, it is enough to heat the water to 32º. At temperatures above the specified value, hot water is first mixed with aggregates, then cement is added in portions.

Increasing the mixing period will help maintain the temperature of the solution. Thoroughly mixed concrete will quickly take its positions in the formwork and will cool less along the way. Therefore, builders recommend increasing the mixing time of concrete mixture components by 25% to optimize fluidity and using finely ground cement.

The simplest heating of concrete mixture

An option with separate heating of water, aggregate or the entire mixture in a concrete mixer by installing a brazier, a heat gun, or a gas burner next to it is suitable for those who are puzzled by the question of how to fill the foundation in winter with light frosts at night and positive thermometer readings during the day.

This scheme has strict rules:

• heating water max up to 80º C;
• initial mixing of water with aggregate and subsequent gradual introduction of cement, preferably with M from 400 to 500;
• the use of additives that increase the hardening rate.

Advice. The use of a vibration device is not a necessary condition for private buildings, but desirable. A construction vibrator is needed to compact the concrete mixture, reduce air content, and reduce porosity.

After pouring, the concrete mass is immediately carefully covered with tarpaulins, bags, insulating mats, slag felt blankets or straw. Until strength gains, the temperature must be maintained by installing braziers or other heat-generating devices around the foundation. Then the heating is stopped and the formwork is dismantled. If the concrete cannot be fully cured, it can be allowed to freeze. All processes will be preserved, and after defrosting the reaction will proceed as usual minus the period between freezing and reverse action.

Attention. Stripping is carried out only after sufficient strength has been gained. According to SNiP III-15-76 regulations, the structure must gain 70%, regardless of the grade of concrete without additives.

Typically, “unfrozen” foundations built according to the rules do not lose more than 5% of their design value in strength properties if the water-cement mixture ratio was no more than 0.6.

Mixing concrete in frosty conditions is a difficult task. A justified decision by a reasonable owner would be to turn to the services of builders or purchase a ready-made solution with modifying additives at the factory. There the proportions will be calculated and weather conditions will be taken into account. With a ready-made solution, solving the question “how to properly fill a foundation with your own hands in winter” will no longer be an impossible task.

Use of concrete with modifying additives

The introduction of antifreeze additives into the solution is also aimed at increasing the thermal energy generated by the concrete itself. In addition to this stimulating effect, modifiers lower the “threshold” for water crystallization. Due to this, the hydration of concrete will take place according to the usual scheme at a temperature lower than for standard conditions.

In order to develop anti-frost properties, concrete is enriched mainly with calcium chloride. No more than 2% of the total mass can be added to the solution, otherwise the compressive strength of the concrete structure will significantly decrease. When the thermometer readings are stable below zero, the solution is mixed with sodium chloride (ordinary salt), potash, sodium nitrate, which ensures trouble-free concreting at -15º below zero. Despite the availability of additives, craftsmen looking for methods on how to pour the foundation for a bathhouse in cold weather should not experiment with solution formulas. It is better to purchase a ready-made composition without the risk of irretrievably losing all the money invested.

When using anti-frost modifiers, you can begin dismantling the formwork when:

• a solution with M200 will gain 40% strength;
• concrete with M to 300 will gain 30%;
• concrete marked M400 and above will gain 20%.

Most often, the use of concrete with modifiers is combined with artificial heating methods. When combining improved concrete, for example, with electric heating, it is necessary to take into account that urea will decompose at + 40º C, and due to potash heated to 30º, the strength will be reduced by 30%.

Technically complex methods of winter concreting

Let us briefly consider methods of artificial heating of concrete in formwork, the purpose of which is to increase the rate of setting of the mixture. Depending on the possibility of using electrical appliances, the availability of insulating materials and the financial framework of construction, the owner of a country estate can choose, or rather, order from a construction organization:

• concreting using the thermos method. Leakage of thermal energy and cooling of the body of the concrete mass are eliminated by the insulating sheathing constructed around the formwork. It is a metal casing with an electric, steam or water circuit that heats hardening concrete;
• pouring the foundation with steam heating. To implement concreting with steam heating of the solution, you will need powerful equipment and a considerable amount of water. It is necessary to accurately calculate the number of pipes installed in the formwork and build a pipeline supplying steam, which will forever remain in the body of the structure. Due to the considerable cost and complexity of implementation, few private owners prefer steam heating.
• installation of a greenhouse around a poured foundation It’s also not the cheapest way, because you need to build a large tarpaulin or plastic tent. It is necessary to maintain a constant temperature inside the tent and monitor the humidity so as not to dry out the concrete. The greenhouse is heated with portable stoves, cannons, and electrical equipment. A separate project is created for the construction of the greenhouse; it is dismantled after the formwork is removed.
• concreting with electric heating, carried out by starting current through wires with a steel core located in fresh concrete. The formwork or reinforcement structure is “entangled” with a wire with a calculated pitch, or the heating cable is simply laid in the concrete. Compared to the above options, this is the most economical and easiest to implement method, and therefore the most common.
• infrared and induction electric heating options, arranged by analogy from tubular heating elements, carborundum rod emitters or cables that create magnetic fields in reinforcement or steel formwork.

All of the methods listed do not belong to the category of work that should be undertaken without knowledge and qualifications. You need calculations of the amount of energy supplied, design of additional devices, and also the skills of a good electrician for electrical methods.

General rules to follow

Let's start with the fact that everyone who wants to know whether it is possible to fill the foundation in parts in winter conditions will probably be disappointed with the answer. A definite no. And until the filling is completed you will have to work around the clock. Laying should be done in segments that are small in height and length, immediately covering them with the next layer to avoid temperature loss. If for some unforeseen reason a helium shell begins to form on the surface of the poured concrete, it must be chipped off.

It is important to properly prepare the object for pouring:

• clear the pit or trench of snow, chip and remove ice from the bottom and from the reinforcement. To prevent freezing and icing of the bottom, you need to cover the trench or foundation pit with straw immediately after digging and laying the sand cushion;
• warm the bottom between the walls of the formwork approximately 30 cm. Do not pour concrete on top of frozen soil! Thawing under the mass of the solution, the soil will settle. It is not a fact that the settlement will be uniform. Moreover, there is no certainty that the foundation will not sag too much;
• provide access to the formwork from all sides.

There are few rules for safe, effective concrete pouring in winter, but they must be strictly observed. It is much easier to be diligent before pouring and during the process than to waste time and money on dismantling and alterations.

How to properly fill a foundation in winter with your own hands: work rules

Anyone who wants to economically and reliably build a solid foundation for a bathhouse at a time when the cost of building materials is affordable should learn how to pour a foundation in winter.

Pouring a foundation in winter is a labor-intensive and technically complex type of work that requires careful preparation and strict adherence to building regulations. Until recently, building the foundation of a house at subzero air temperatures was not feasible due to the lack of conditions necessary for the natural hardening of concrete. With the advent of new technologies, pouring the foundations of buildings in winter has become easier and more affordable.

The nuances of concreting in winter

The basis for hardening of a concrete mixture is hydration, which is accompanied by the transition of the material from a liquid state to a solid monolith. With a favorable level of humidity and an average daily temperature above 0 °C, a gradual increase in the strength of the foundation of the house occurs. In winter, instead of hydration, water crystallizes, which prevents the formation of strong molecular bonds and increases the porosity of the concrete mixture by 10%.

As a result, the strength of the foundation is significantly reduced and does not reach the planned level. Is it possible to pour the foundation in winter? Yes, if you use one of the developed methods for constructing a foundation at low temperatures. The choice of a particular option depends on the following factors:

• climate nuances during low temperatures;
• house dimensions;
• the ability to increase the temperature of water and aggregate.

The brand of cement used, the fineness of its grinding, the chemical composition and proportions of the components of the solution are also important, which help to slightly increase the temperature of the mixture during the process of natural hydration.

It is allowed to heat only water and aggregates, since a similar action with cement worsens its binding properties.

Why do you need to build a foundation in winter? In private construction, such a need may be caused by the following reasons:

• Construction of a house on areas with soil prone to crumbling. In winter, the soil freezes, holds its shape well and allows you to make a foundation pit without much effort.
• Construction of buildings in areas with harsh climatic conditions. In this case, the warm period is short-term and is not always suitable for installing a foundation for subjective reasons.

In some cases, the construction of the foundation of a building during frost is justified by low prices for materials and the availability of free time for developers or owners of future real estate. Among the disadvantages of pouring the foundation of a house in winter are the need for special equipment for digging trenches, low productivity of work and additional costs for heating and purchasing additives.

Foundation construction technology in winter

When constructing the foundation of a private house in conditions of low temperatures, it is advisable to use a concrete mixture with modifying additives, and upon completion of the work, cover the structure with thermal insulation. Other methods are labor-intensive and require special skills.

To build a foundation in winter, you need the following:

• concrete solution;
• modifying additives;
• crushed stone;
• rods or mesh for reinforcement;
• building level;
• materials and tools for making formwork;
• shovel;
• thermal insulation;
• concrete mixer.

First, formwork is made around the perimeter of the dug trench and a reinforcing frame is installed. Then the concrete solution is mixed, adding special components to it, the foundation of the house is poured and left for 3 days. During this period, the mixture hardens, after which it should be insulated.

At temperatures below -20 °C and humidity 60% or more, foundation construction work is not carried out.

Simple ways to fill a foundation in winter

There are three directions for creating conditions for foundation hardening: heating the mortar and formwork, as well as adding modifying additives to the concrete mixture. Each of them has its own characteristics and specific application.

Heating the solution

If you need to fill the foundation in winter with positive daytime temperatures and slight frost at night, then it is advisable to use the separate heating method. Using a heat gun or gas burner, the aggregate, water or concrete mixture is heated, fulfilling certain conditions.

Among them are:

• the maximum permissible water heating temperature should not exceed +80 °C;
• the preparation of the solution begins with mixing the aggregate with water, followed by the gradual introduction of cement grades M400 and M500;
• introduction of additives that reduce the curing time of concrete.

To obtain a mixture with a homogeneous structure and high density, vibration equipment can be used. It reduces the air content and reduces the porosity of the material. After pouring is completed, the foundation of the house is covered with insulating mats, bags or tarpaulins and the temperature is maintained until the foundation becomes strong. Then the formwork is removed, observing the rules for carrying out concrete work during low temperatures.

Construction of formwork

At slight negative temperatures, the thermos method without heating with electric heat sources, which involves installing thermal insulation around the formwork, will be effective. To do this, insulation is laid on all sides of the base, having previously secured a vapor barrier material. It performs two functions: it allows evaporating moisture to pass from the surface of the concrete and protects it from the penetration of precipitation.

Use of additives

The introduction of modifying components into the solution helps to increase the thermal energy generated by concrete during hydration. Also, special additives reduce the level of water crystallization, as a result of which the hardening of the foundation of the house occurs at a lower temperature. To form frost resistance, calcium chloride, sodium nitrate, and potash are introduced into the solution.

To properly harden the base of a building, you can combine concrete with modifying components and artificial heating.

Technically complex methods

In addition to natural heating of the concrete mixture when pouring the foundation, you can also use artificial methods using electrical appliances. These include:

• Concreting using the thermos method. An insulating sheathing is made around the formwork, which is a metal casing with a water, steam or electric circuit for heating the concrete. This design prevents heat loss and reduces the cooling rate of the base.
• Concreting with electric heating. It is performed using a current that is passed through wires laid when pouring the solution. The cable can also be used to entangle reinforcement or formwork. This option of concreting in winter is characterized by ease of execution and low cost.
• Infrared and induction heating. In this case, the heat source is heating elements, special emitters or a cable, which helps create magnetic fields in steel formwork or reinforcement. This option of maintaining the required solution temperature requires special devices and complex preliminary calculations.
• Pouring solution with steam heating. This method is highly labor-intensive and is carried out using powerful equipment and a large volume of water. Pipes are installed into the formwork structure, combining them into a single system for supplying steam and heating the foundation.
• Construction of a greenhouse. A device of this design is a costly heating method. First, you need to erect a tent made of tarpaulin or polyethylene around the foundation of the house, and then maintain the desired temperature inside using heat guns, electrical appliances, or portable stoves.

The use of technically complex heating methods requires significant financial investments, therefore, the effectiveness and necessity of winter filling of the base should be assessed.

Requirements for construction work

To ensure the strength and reliability of the foundation of a house when pouring it in winter, it is necessary to follow some rules. Firstly, work cannot be carried out in parts with long periods of time between each pour. The concrete solution is laid in small segments, quickly covering them with the next layer. This avoids heat loss and keeps temperature changes to a minimum.

Watch the video to see what points need to be taken into account when pouring the foundation in winter.

In addition, it is also necessary:

• Thoroughly clear the prepared trench of snow and remove any ice that has formed from the reinforcement and the bottom of the ditch;
• cover the pit with insulating material;
• pre-heat the bottom between the formwork walls;
• provide passage to the formwork.

It is forbidden to pour concrete on top of frozen soil, since when it thaws it will settle and can cause the foundation to sag.

In the summer, building both the foundation and the structure itself is faster, easier and cheaper. But this is not always possible. This is due either to personal employment or to the short duration of the warm period. Thanks to the use of modern materials and the implementation of new technological solutions in practice, the question of whether it is possible to pour a foundation in winter has practically lost its relevance. These works are successfully carried out at sub-zero temperatures. Today, the effectiveness of concreting in frosts is being discussed from the point of view of economic and labor costs.

Features of foundation construction in winter

Making a foundation at low temperatures is not an easy process. Workers will have to work in the cold. Winter is generally considered not the best time to create a monolithic structure of slab or strip type, or to build piled and bored types of foundations. The main reason for this is that water, which is one of the main components of the working solution, crystallizes at temperatures below zero.

The formation of ice interferes with the normal process of formation of reliable bonds between concrete molecules - its hydration. Also, the expansion of water when freezing leads to a significant reduction in the strength of the foundation. This occurs due to the formation of pores in the concrete by ice crystals.

The hydration process itself occurs with heat release. Moreover, the larger the size of the concrete structure, the higher the heat transfer, and the cooling of the pour occurs more slowly.

In general, in winter, construction is carried out in the following cases:

• when the summer period is short, which is typical for cold northern regions;
• if it is necessary to erect the building as quickly as possible to the planned date;
• The reason for this may also be the properties of the soil at the construction site.

It is also taken into account that some Construction Materials You can buy it cheaper in winter than in summer (during the work season). For builders, cold weather is a period often characterized by small volumes of orders or their absence. Mostly employed are those who specialize in interior decoration. Due to the increased supply of services, prices for them fall. They also pay attention to this when starting construction in winter. But there are no significant savings, because the work is carried out using more complex technologies.

The disadvantages of pouring concrete in winter are:

• complexity of the work;
• the need to attract heavy equipment;
• difficulties with organizing the heating of the foundation being built;
• increased costs for purchasing additives that increase the frost resistance of the solution.

Due to the release of heat by concrete during hardening, when working in frosty periods, preference is given to strip or slab (monolithic) types of foundations rather than columnar ones. During their construction, if the temperature environment slightly below zero, then you can even do without special additives and heating, using thermal insulating formwork and a special covering (made of mats).

When starting construction, you should take into account that it will not be possible to carry out excavation work on frozen ground yourself, manually. This will require the use of technology.

Concreting technologies

It is possible to make a foundation in winter using various technologies. The choice of option for creating and maintaining the conditions necessary for the concrete hydration process to proceed normally depends on the following factors:

• from the chemical substances included in the working concrete solution, their proportional relationships;
• dimensions of the structure being created;
• climate characteristics of the area;
• availability of power supply network;
• brand of cement used;
• Possibility of organizing heating of water and liquid additives.

The more crushed the cement particles are, the faster it enters into a chemical reaction, releasing heat.

Normal work is facilitated by heating the aggregate and water to 32 degrees immediately before mixing. The temperature of the working solution in this case will be approximately 21º C. It must be taken into account that the cement cannot be heated, because it will lose its binding properties.

The solution must be mixed thoroughly. It is also recommended to increase the mixing time by approximately 25% compared to summer.

Application of concrete additives

The main method that allows pouring a foundation during cold weather is the introduction of antifreeze additives into its composition. Their introduction causes an increase in the amount of heat independently generated by concrete. Supplemented with increasing heat transfer, modifiers lower the crystallization temperature of the liquid. Thanks to this, the hydration process of poured concrete at lower temperatures proceeds in the usual way.

Calcium chloride is often used as an additive that increases frost-resistant properties. It is introduced into the working solution in an amount not exceeding 2% of the total mass. If this proportion is exceeded, the compressive strength of the created base is significantly reduced.

At a stable temperature level around -15 degrees, the following substances are used to add to concrete:

• table salt (sodium chloride);
• sodium nitrate;
• potash.

The use of concrete modifiers is often combined with the organization of artificial additional heating of the base.

If anti-frost fillers are used, the formwork is dismantled when M400 concrete reaches 20% strength. For M and M300 this figure should already be 30%, and for M200 – 40%.

It is not recommended to independently experiment with adding available components to filling compositions. It is better to use ready-made building materials.

Warming up the poured base

In practice, different methods of heating a poured base are used. The simplest option is to preheat the water and filler, or the entire solution. Suitable for these purposes:

• fryer;
• heat gun;
• burners of various types;
• an ordinary fire.

Modifiers are added to concrete to speed up the hardening process. After pouring it, the entire structure is covered using the following materials:

• bags;
• tarpaulin;
• straw;
• thermal insulation mats.

You can also cover with rags or unnecessary blankets. Braziers or other heat-producing devices are installed around the base. They are used until the concrete reaches the required strength.

You can make a kind of tent around the structure, which will contribute to more efficient energy consumption. But in this case, it is necessary to monitor the humidity level so as not to dry out the poured concrete. You will also need to draw up a separate project for the structure and dismantle it after the work.

After the monolith reaches the required strength (according to SNIP III-15-76 it is 70% and does not depend on the brand), the formwork and insulation are dismantled. If the concrete has not completely hardened, it can be allowed to freeze. After defrosting, all processes will continue in the right direction, and the strength will be lost by approximately 5% of that calculated according to the project.

Alternative heating methods and their implementation are presented in the table below.

№	Method of heating poured concrete	Practical implementation
1	creation of a "thermos"	To do this, a heat-generating casing is installed around the perimeter of the formwork, consisting of a metal casing with a steam or electric or water circuit located inside it
2	heating the fill with steam	This method is implemented by laying the required number of pipes in the formwork, through which steam is supplied from a specially created pipeline
3	use of electricity	To implement this option, a steel wire is used to heat the poured solution, fixed in a certain way in the reinforcement frame or on the formwork, or simply laid directly in the concrete, through which an electric current is passed
4	use of induction heaters	such devices located along the perimeter of the foundation warm it up by heating reinforcement or metal formwork with an electromagnetic field

Infrared heaters are also used in practice. Steam heating is an expensive and labor-intensive method that is used quite rarely.

The point of all methods is to speed up the setting of the solution.

Of all the methods considered, the most accessible are simple insulation of the base with various materials (followed by heating it) and installation of an electric heating circuit. Carrying out heating work requires the performer to have a certain level of qualifications in this field of activity, so specialists should be involved.

Pouring a foundation in winter requires strict adherence to a number of nuances. The rules for carrying out the work are as follows:

• It is not allowed to fill the base in parts: the formwork mounted under it should be completely filled with mortar;
• in order to avoid heat losses when laying concrete, the layers must be made of small height and length, immediately overlapping them with the following ones;
• when a helium shell forms on the surface of the fill, it must be chipped off;
• during the preparation of trenches for the foundation or foundation pit, they should be thoroughly cleared of snow and any existing ice should be knocked off the reinforcement;
• immediately after digging and laying the sand cushion, you need to lay straw on the bottom: such a cover will prevent it from icing;
• It is impossible to pour concrete on frozen soil; it must be pre-warmed;
• it is imperative to ensure free access to the formwork from all sides;
• if, after digging, water appears at the bottom of a trench or pit, then it must be removed;
• it is better to use formwork with increased thermal insulation properties;
• Until the concrete reaches a sufficient level of strength, it is necessary to heat the entire poured structure, maintaining a positive temperature.

If you lay concrete directly on frozen soil, then under the influence of heat generated as a result of hydration of the solution mass, the soil will begin to thaw and sag. In this case, the settlement may be uneven and the foundation may be deformed.

There are few rules for the correct, effective implementation of concrete pouring work. But they require strict compliance. It is easier and more economically feasible to perform them during preparation and during pouring than to redo everything afterwards.

Methods for pouring a foundation in winter are shown in the videos below.


It is possible to build a concrete foundation in winter. A high-quality result is achieved by using anti-frost modifiers or creating a heating system, or combining these two methods. In this case, it is recommended to use ready-made additives sold in construction stores from well-known manufacturers and finely ground cement. An important point is careful adherence to the technology of work and the nuances of the process.

Not so long ago, the arrival of winter for builders was associated with forced rest. Construction projects came to a standstill, awaiting more favorable weather conditions. What are we seeing now? The process does not stop even in frosty weather: hundreds of workers are working on the construction of buildings of various “calibers”.

The latest technologies have shaken the conservative views of many ordinary people, but have caused a storm of protest among others. There is especially debate about such an important stage of construction as.

For ardent fans of the “classical” method of construction, the question itself causes a storm of emotions. How can you pour concrete in cold weather? After all, these are incompatible things!

Their arguments are convincing because they are based on the physical properties of the building material. One of the components of concrete is water. It “transforms” the dry mixture into a liquid “dough”, organically linking together the other components of the “cocktail” (sand, crushed stone and cement).

What happens to water at temperatures below 0ºC? That's right, she's freezing. By mixing concrete and leaving it to harden in the cold, you trigger a destructive “mechanism”: water crystallizes and “tears” it from the inside. Instead of a strong and reliable foundation, we get a fragile, unusable “dummy.”

But what was previously impossible has been practiced for a long time. There is a technology for pouring foundations in winter, which arose in the wake of the development of high-speed construction. It allows you to form the “sole” of buildings at sub-zero temperatures (down to -15ºС). Moreover, there are several completely different methods:

• Artificial heating of the area using heating devices

It is known that concrete gains maximum strength in the first two days. Therefore, it is during this period that the “base” should be especially carefully protected from frost. To do this, heating devices (heat guns) are installed around the perimeter of the site, which maintain the optimal temperature of the hardening concrete. The power of the equipment depends on the area of ​​the “sole”.

• Heating the foundation using power

This method is also based on heating the “sole”, but unlike the convection method described above, it uses conduction - the transfer of heat from hot to cold. It is not the entire area of ​​the site that is heated, but only the concrete itself. To do this, electric current (380 V) is supplied to the reinforcing “mesh”. The iron rods heat up and heat the concrete.

• Use of special additives for concrete

This method is based on introducing an additional component into the mixture, which inhibits the freezing process of water. For these purposes, salt additives are used: sodium chloride and potassium chloride. Their concentration is expressed as a percentage relative to the amount of water in the mixture. On average, this figure ranges from 2 – 15% and depends on the strength of the cement (its grade) and weather conditions (the lowest temperature during work). Concrete “seasoned” with special salt additives is called cold.

After taking a closer look at the technology of pouring a foundation in winter, a completely logical question arises: do you need it - to get involved with winter work? After all, all of them in one way or another lead to an increase in construction costs. What arguments guide such haste?

Points for and against

Why is there a need to start construction in winter, and not in a more favorable period?

Here is the “hit parade” of the main reasons:

• Plot of land with “fragile” soil

In winter, excavation work on such a site takes place without problems, since the frozen soil “holds” its shape well. Once the temperature rises to above-zero levels, it becomes much more difficult to dig trenches: you have to constantly deal with crumbling edges, which complicates the work of builders.

• Living in an area with a harsh climate

Such weather conditions simply force us to work in winter. If construction had been carried out only during a short period of thaw, then its completion time would have been too extended.

• Winter “markdown” of building materials

Despite the possibility of construction work all year round, there is a noticeable decline in this industry in winter. The “hot” trade in building materials is calming down, so many retail outlets are cutting markups to stimulate customers. In addition, there are no interruptions with “scarce” goods.

The same applies to construction services. In winter, labor is much cheaper than during the peak season. Therefore, the decision about whether it is possible to pour a foundation in winter puts pressure on the average person’s subconscious, tempting him with the opportunity to save money.

• Availability of free time

It's not just builders who have more free time. Some industries also suspend their activities during the winter. People are starting the big holiday season. Winter construction works- the only chance for them to start their construction and have time to finish it before the “hot” season.

In addition to the listed arguments “FOR”, there are a number of negative factors that every builder who wants to start work on the foundation in winter should take into account:

• Economic benefits may turn into additional costs

Laying out a foundation for a small garage in winter will cost more. Please note that it is almost impossible to dig trenches in frozen soil yourself. You will have to resort to the services of special equipment. The same applies to ways to fill the foundation in winter. All of them, one way or another, will additionally “hit” the owner’s pocket.

• Don't be happy with "free" concrete

Very often the idea to start construction in winter arises due to a “gift” of fate: advantageous offer buy ready-made concrete. Excess building materials from large construction sites are sold “for pennies.” But one important nuance is forgotten - they offer you regular concrete, and not its winter counterpart. In connection with this nuance, a very unpleasant surprise may await you. The money will be wasted.

• Harsh working conditions

Street work in winter is slower and therefore requires the involvement of more people. You should also provide a place where cold workers can warm up, and this is not always possible in a remote area.

All objective facts are listed. All that remains for you is to evaluate all the “PROS” and “CONS”, “trying on” your specific situation with them.

If the decision to start the “winter” pouring of the foundation has tipped the scales, then we will describe the nuances of this process.

How to pour the foundation yourself?

Of all the methods of “winter” pouring a foundation for self-built houses, only one is suitable - special additives to concrete.

The other two methods are no longer available for quite objective reasons:

1. Artificial heating of the site is too expensive and labor-intensive.
2. Electrical supply to the fittings is carried out only by specialized specialists. Such work is associated with mortal risk, and it is impossible to organize it yourself.

Let us dwell in more detail on “winter” additives to concrete and the features of their use. There is now a wide selection of different types of plasticizers on the market. Manufacturers even offer 2 in 1 options: rapid hardening and frost resistance of concrete.

For convenience, most additives are produced in the form of a liquid, which is poured into the mixture being prepared along with water. The amount of substance introduced depends on the air temperature and the strength grade of the concrete (the scale is indicated in the instructions). When using additives, you should remember the following nuances:

• The use of a frost-resistant additive reduces water consumption (on average by 10-15%);
• The minimum temperature at night should not fall below -20 ºС;
• Concrete with a frost-resistant additive cannot be poured in rain or at high relative humidity (above 60%);
• Read the instructions carefully, since additives have “contraindications” for fittings made of certain types of steel;
• The frost-resistant additive is incompatible with some concrete aggregates (for example, silica);
• Experienced builders advise additionally heating the water when mixing concrete (but this is not a necessary condition).

On the third day after pouring the foundation, it should be insulated. To do this, cover the entire accessible surface of the “sole” with a layer of sawdust (20 cm), dry grass or turf (20-30 cm). The formwork is left until spring and removed immediately before the start of another stage of construction work.