Is it possible to fill the foundation in frost? How to properly fill the foundation in winter: safety rules for concreting in cold weather. At what temperature can the foundation be poured

Any construction is best done in dry warm weather. But a private house, if it is being built with your own hands, is being built in your free time from work. One warm season is usually not enough for this. In order not to stretch the process for many years, some of its stages are carried out in the winter.

The grillage (or foundation) can be prefabricated from blocks or slabs. In this case (as well as during construction), the peculiarity lies in the fact that the fixation of individual elements is performed with a cement-sand mortar. Basically the same rules apply to it as to concrete.

Pouring the foundation in winter at minus 5

Measures required for the construction of a quality foundation in winter:

• using modifiers;
• heating the solution;
• thermal insulation of the finished foundation.

The problematic component of concrete is water. Even if it is liquid during pouring, full dehydration is impossible. Those. the solution does not set due to the evaporation of water, but freezes. This problem is solved by adding special modifiers to the mixture, which slow down the hardening, which allows the concrete to gain strength.

The modifying substance is selected in accordance with the indicators of frost resistance. The required amount is indicated in the instructions, there is a scale on the package: the norm depending on the temperature. The minimum permissible air temperature is -25 degrees.

note

When preparing a solution with a modifier, the amount of water is reduced by 10-15%. If the air humidity is high (60% or more), additives cannot be used.

You should also study the instructions for the interaction of the ingredient with the metal.

Heated water is used to dilute the mixture in winter. The poured foundation needs to be warmed up, especially the first couple of days. For warming up, you can use a heat gun (power is selected depending on the size of the foundation). Another option is a heating cable or reinforcing rods with a 380 volt electric current supplied.

Concrete gains strength within a month. After that, you need to make a vertical and, as well as insulate the finished base. If there is a lot of time left before the arrival of spring, the foundation is preserved: it is covered with a waterproofing film and heat-insulating material:

• expanded polystyrene (foam);
• sand;
• expanded clay;
• sawdust;
• priming.

All heaters are in one way or another hygroscopic, they need to be covered from above with dense polyethylene.

The easiest option is to cover the base with snow. In this case, the film must be laid under the snow, otherwise the concrete will absorb water during the thaw.

The work methods used by professional builders are improving. New technological methods reduce the duration of construction activities, increasing the quality of the structures being erected, regardless of climatic conditions. Until recently, developers, pondering whether it is possible to fill the foundation in winter, gave a negative answer. Now the approach has changed - the technology allows concreting in winter, ensuring the quality of the concrete.

A different approach to the question of whether it is possible to pour concrete in winter

Discussions periodically arise between builders about the possibility of performing concrete measures at temperatures below zero degrees Celsius. There are two positions:

• supporters of traditional methods are sure that cement hydration can only take place at a positive temperature. They deny the possibility of using special techniques and believe that concrete strength is lower in winter and concrete pouring in autumn is preferable;
• adherents of the latest technology do not doubt the effectiveness of proven know-how. They believe that it is possible to concrete a foundation in winter, regardless of the level of temperature drop, and at the same time ensure the strength characteristics of the foundation.

Each opinion is based on certain views and experiences. Let us dwell in detail on the features of the implementation of concrete measures in cold climatic conditions. The main task is to prevent water crystallization. After all, frozen ice crystals increase the porosity of the massif and create an obstacle for the hydration of the concrete mixture.

Pouring the foundation in the winter is quite feasible.

Filling the foundation in winter - how does hydration proceed

Provided that special methods are used, involving the introduction of additives or heating the solution, the hydration process does not differ in winter and summer.

It provides for the following stages:

• the formation of a surface film based on sodium salts;
• absorption by the binder of water in the outer layer of the massif;
• contraction of the outer layer with a simultaneous increase in density;
• termination of moisture absorption and further increase in hardness.

The concrete mass acquires operational hardness gradually:

• the initial setting of the solution lasts no more than 24 hours. The liquid mixture hardens, but it is not strong enough to perform further work;
• the final set of hardness occurs within 28 days. The duration is influenced by weather factors and the recipe.

The construction of the foundation in the winter has its own characteristics. As a result of crystallization, water freezes in concrete pores, which deteriorates the strength of the massif. The main requirement for winter concrete pouring is the creation of a temperature favorable for hydration of the solution.

Pouring the foundation in winter - methods used

By maintaining the optimum temperature, builders ensure the required duration of concrete hardening.

Winter foundation is the only way to accelerate the pace of construction in a harsh climate zone

For this, various methods are used:

• steam heating;
• heating with electricity;
• directional heating with an infrared source;
• temperature rise by induction radiator;
• protection of concrete with a thermal tent;
• thermal insulation of the array with heat-insulating formwork;
• introduction of additives to prevent water freezing.

Consider the features of popular technologies.

Using steam heating

Hot steam is able to deeply heat concrete and create favorable conditions for hardening. Heat treatment of concrete for 24–36 hours with steam heated to 75 ⁰C is equivalent to gradual settling of concrete for a half month at a positive temperature.

The duration of processing is determined by the following points:

• the required hardness of the monolith;
• the used brand of Portland cement;
• the intensity of heating.

Heat treatment is carried out by creating a steam jacket. It is built close to the surface of the formwork and allows the steam to flow freely around the concrete.

Quite a laborious and costly method, since it involves heating a trench, foundation pit or concrete to a higher temperature

The use of electrical energy

With the help of electricity, it is possible to provide normal conditions for a set of hardness. The following methods of raising the temperature are popular:

• use of a heated cable of PNSV brand, which, after laying, is poured with a concrete mixture;
• application of electric heating from a step-down transformer through electrodes inserted into the array.

The method of electrode heating does not require significant costs and provides for the use of various conductive elements:

• stretched wire. A vertically positioned string is effective when concreting elongated structures in the form of support columns or load-bearing beams;
• reinforcing bars. Depending on the size of concrete products, the rods are immersed in the solution to the required depth and cannot be reused;
• metal plates. Plate electrodes are placed on oppositely located formwork panels, providing direct contact with the mortar.

The greatest effect is provided by the use of a heating cable. The technology allows you to regulate the heating intensity of the wire that transfers thermal energy to the concrete mass.

This method is feasible at any temperature and weather conditions.

The following heating methods are less popular in the construction industry:

• infrared;
• induction.

They have serious disadvantages associated with increased energy consumption, implementation complexity and uneven heating of large volumes of concrete.

Construction of a thermal "jacket"

The construction of an easily erected tent with internal heating is an economically viable method. The main elements of the tent:

• power structure made of a durable metal profile;
• overlap made of polyethylene film or tarpaulin material.

Heating inside the structure is carried out using the following equipment:

• heat guns with autonomous power supply;
• portable stoves using various energy sources.

This construction method is very suitable for all weather conditions, even in the most severe frosts.

Heating of formwork panels

The heating of the formwork panels is also used to maintain the temperature regime. It is based on the formation of a thermal insulation cladding based on the elements of the formwork structure.

Various heat transfer fluids are used:

• water vapor;
• Electric Energy;
• hot water.

The heating circuit is formed from hermetically connected lines that transfer thermal energy to the solution. This method has weak points:

• uneven evaporation of moisture from concrete;
• the appearance of cracks in the heating zone.

At the same time, situations are possible when the heating of the formwork is the only possible method of maintaining the temperature.

Is it possible to fill the foundation of the cottage in winter

The financial capabilities of private developers do not always allow the use of industrial heating techniques. After all, it is problematic to purchase or rent special equipment, as well as maintain the required temperature throughout the day.

As you can see, pouring the foundation in winter has its advantages.

That is why fairly simple technologies are used in the construction of private buildings:

• warming up the concrete mixture at the preparation stage;
• introduction of frost-resistant modifiers into the solution.

Using these techniques, you can concrete the base of a private house in winter.

How you can increase the temperature of the mixture yourself

It is not difficult to increase the temperature of the concrete solution on your own, observing the following rules:

1. Heat water to 75-80 degrees Celsius.
2. Mix it with filler.
3. Add cement to the mixture.
4. Stir by adding hot water to the desired consistency of the solution.

After pouring, use a vibrator to eliminate air pockets.

The use of additives to increase frost resistance

To carry out winter concreting without the use of energy-intensive heating processes, frost-resistant additives, which prevent water crystallization, allow.

Today in the construction industry, different types of additives are used to improve the quality of concrete and its hardening.

To ensure the desired effect, you must:

• study the manufacturer's instructions;
• analyze the compatibility of components with the materials used.

Self-application of additives does not cause difficulties for private developers.

Preservation of the foundation for the winter

Private developers are interested in whether it is necessary to cover the foundation for the winter, as well as when to close the air vents in the foundation for the winter. Preventing overcooling of the newly poured concrete base contributes to its strength. In this case, the sealing of the vents should be carried out before the onset of the first frost.

Conserve the base in stages:

1. Waterproof the base. Waterproofing of the foundation in winter is carried out 30 days after concreting and provides for covering the surface with polyethylene or roofing material. When the aquifers are located close, a drainage system is constructed.
2. Insulate the surface. Thermal insulation will allow you to maintain a favorable temperature and humidity for a long time, exclude the influence of temperature extremes. Expanded clay, expanded polystyrene, sand, sawdust or straw are used as insulation.

It is important to reliably cover the heat insulator with polyethylene and fix the film with heavy objects.

Conclusion

Not all of the winter concreting options can be used by private developers. Study the technology thoroughly and perform an economic analysis. Only then choose the best method. In addition, there is another option - wait for warming and save money.

If the house is being built with your own hands, then it is not always possible to choose a favorable period for construction. Sometimes vacation falls in the winter, so you have to look for a way out of the situation. Is it feasible in winter? Yes, but it will be more difficult to do this than in the warm season. There are two solutions to the problem:

1. Construction. We are not waiting for the arrival of spring, but taking the situation into our own hands. We select special solutions, a suitable type of foundation and start work.
2. Preservation of the foundation for the winter. For example, you started construction work in November, but you don't really want to continue construction. Sometimes this is simply not feasible, so you need to leave work until spring.

We will analyze both options in detail, since both construction and conservation are complex and time-consuming processes, so it is better to entrust them to professional builders.

We build in winter - types of foundations

For winter construction, there are two main types of foundations that can be used in the cold:

• Strip foundation. To facilitate the work, the masters recommend making a choice in the direction of ready-made blocks. It is better to leave "wet" operations for a warm period.
• Pile foundation. The base, where concrete piles are used as the main element, will be an excellent solution for lightweight structures. Usually, a pile foundation is chosen for wooden houses.

Preparing concrete mix

Of course, you won't be able to make a strip foundation in winter from ordinary concrete. Here you need a solution containing special additives. These modifiers prevent the concrete from hardening ahead of time, the mixture sets only after the required strength has been achieved.

Also, "winter" additives contribute to easier pouring. The choice of the right mixture should be handled by a professional, since they differ in the speed of hardening and frost resistance. The packaging usually indicates how many modifiers should be in the concrete mix.

Pile foundation in winter

This type of foundation can be erected in all seasons. Builders do not need to adapt to the weather, as it does not affect installation work. Construction proceeds as follows:

1. Piles are screwed into the frozen soil to the depth of freezing. Usually the distance is 1.5 meters.
2. The next step is leveling.
3. Next, the foundation is poured with a concrete mixture.
4. Now you can put the heads on the piles.
5. If necessary, carry out waterproofing and thermal insulation.
6. Piles help to evenly distribute the load over the entire area of ​​the foundation.

Features of the use of additives

Before starting work, you need to familiarize yourself with the main features of modifiers. Water for the solution needs 10-15% less when compared with the usual mixture. Modifiers perform their tasks up to a certain frost threshold - this is -25 degrees. You also need to monitor the humidity of the air. If this figure exceeds 60%, then additives cannot be used.

We often repeat that a professional should choose a solution and modifiers, because you need to know how the additives will react with a certain type of concrete. Despite the fact that modifiers help to cope with frost, it will not work without thermal insulation. The concrete of the base should be heated so that the temperature of the structure does not change much. Now let's look at the pros and cons of working in winter.

Positive and negative points

The pros are worth considering first:

• The soil does the work of the formwork, since the frozen soil does not crumble;
• Savings on building materials. Do not forget that with the arrival of cold weather, stores are trying to get rid of seasonal materials.
• In some regions, the favorable season for construction lasts no more than 2 months, so leaving work for almost a year is the wrong decision. A "winter" pile or strip foundation will help here.

As you can see, there are pluses. Now let's look at the cons:

• Although building materials will be cheap, excavation will be expensive if you hire builders;
• Some owners decide to leave construction until a warm time, for the reason that it is simply impossible to work at -20;
• Using special equipment in cold weather will be problematic, as a result, more expensive.

Foundation conservation

Conservation can be performed in several stages:

• Waterproofing a finished or unfinished base;
• Thermal insulation of the foundation;
• Groundwater drainage.

To understand how to leave the foundation for the winter without damage, you need to disassemble each item.

Groundwater drainage

Before starting construction, specialists from the construction bureau study the site where the future structure will stand. By examining the characteristics of the soil, it is possible to determine whether it is possible to do without drainage or not. Soil saturated with moisture will not be able to provide the necessary strength for the house. Due to the high humidity, cracks will appear in the concrete, but the strongest impacts for the structure will be in winter - the liquid will get into the pores of the concrete and freeze.

The drainage is carried out using drains and grooves. By performing this action, you will protect the foundation and the future house from the adverse effects of moisture. The scheme is as follows:

• On your site, experts find the lowest place.
• Further, a pit is pulled out, which in the future will serve as a reservoir.
• Around the entire perimeter of the base, it is necessary to dig grooves with a depth of about 40 centimeters. An exception will be the grooves on the side of the pit - there the depth should be increased to 50 cm.
• The drains should be dug perpendicular to the groove, the direction should be towards the tanks.

Waterproofing and thermal insulation

4 weeks after pouring the mortar, you can start making waterproofing. It should be said that such protection is not needed in all cases. In any case, this issue is resolved when planning the foundation.

It is necessary to have time to make waterproofing before the onset of cold weather, this applies to tape and tile structures. If you have chosen a columnar or pile foundation, then waterproofing is not required.

As for the insulation, it is carried out along the entire perimeter of the base. You can choose extruded polystyrene foam as a material. It is convenient to work with him, since the material is sold in slabs. Of course, the thermal insulation is carried out after the waterproofing. After the boards are laid, you can sprinkle shavings or straw around the entire perimeter of the base. Next, the foundation must be covered with a film and pressed down with heavy material. After that, the structure can be safely left for the winter.

Bottom line: is it possible to fill?

As you can see, there are many pros and cons of pouring the foundation in the winter, but the fact remains - if necessary, the foundation is poured even in frosts. Yes, the work is specific, you need to understand the additives in order to get a high-quality solution at the output. If you are not afraid of the cold, then feel free to get to work.

Can the foundation be poured in winter? updated: February 26, 2018 by: zoomfund

Traditionally, it is customary to plan all "wet" works for the warm season. However, it is not always possible to calculate the time in this way, sometimes tight deadlines force us to consider the option of pouring the foundation in winter.

This is especially true for our country, located in a cold climate zone, where frost is common.

It is quite possible to make the foundation of a house in winter, although it will cost significantly more than laying the foundation in summer. The set of measures can be divided into two types:

The specific choice of techniques depends on individual conditions - the construction of the foundation, its dimensions, temperature regime, financial capabilities.

Some bookmarking methods in the cold season can be implemented independently, some will require the involvement of specialists.

Many techniques for laying concrete at low temperatures are described in SNiPs and GOSTs, but companies and builders are constantly coming up with new tricks.

What is the danger of frost?

Water in solution performs two functions - it dissolves substances, and also activates the process of hydration and the formation of silicate crystals. If the temperature goes below zero, the water begins to freeze. Water crystals do not participate in the processes of dissolution and hydration, they displace impurities and sand from themselves.

With further cooling, simultaneously with an increase in the proportion of frozen water, an increase in the volume of crystals occurs, ice begins to expand the stone, breaking only the formed and still very weak bonds between silicate crystals.

As a result, concrete does not gain its design strength, and may even collapse. Such a foundation of a house cannot do its job.

Contrary to popular myth, frozen liquid concrete will not be able to gain the required strength after the frost subsides, since its internal structure has already been irretrievably modified.

The only way out is to prevent the formation of ice crystals in the solution in every possible way.

Antifreeze additives

In Russia, from the very beginning of the use of concrete, there is an active search for effective means that reduce the crystallization point of water. Especially in winter, pouring the foundation is in demand in the northern regions.

In most cases, the supplement complexes offered today are based on:

They can be easily found on sale.

Also, at negative air temperatures, companies selling ready-mixed concrete, as a rule, begin to independently add PMD to their products.

When ordering, it will not be superfluous to find out what frost the solution is designed for. If you decide to make your own foundation in winter with anti-frost additives, then you need to take into account some rules:

It is worth remembering that in cold weather the rate of hardening and strength gain by concrete drops several times. And the use of additives does not speed up this process.

It is also worth remembering that all PMDs, without exception, are electrolytes, that is, they reduce the specific electrical resistance of the solution. This should be taken into account when planning electric heating of concrete in severe frost.

The use of additives seems to be the simplest and most inexpensive way to protect against freezing. However, if used incorrectly, the method creates the greatest difficulties and can lead to the need for a complete replacement of the foundation of the house.

Insulation and heating

A set of measures aimed at preserving or increasing the heat of concrete after pouring is usually more expensive, they are more troublesome than using PMD, but if used correctly, they allow you to get a foundation in frost that is in no way inferior to the summer one in terms of its operational characteristics. Or even surpasses it.

The easiest way is to organize the foundation in winter, if the ground is not frozen and the thermometer scale is kept near zero. In this case, it is usually sufficient to insulate the concrete from above with high quality, protecting it from cold air. You can use sawdust, mineral wool and other insulation for this.

Another way is to organize a greenhouse:

1. The entire space above the poured foundation for the house is covered with a tarpaulin or a film - a tent.
2. A stove is installed in the tent, a fire is made or heat guns are installed.
3. A round-the-clock watch is organized to maintain the optimal temperature in the tent, to avoid sudden changes.

This method allows you to survive even a very severe frost.

In addition, using a tent and heat guns, you can even warm up frozen soil in a trench.

But the costs of building a foundation in a greenhouse in winter are quite tangible.

There are other ways:

Regardless of the method chosen, it is important not to overheat the concrete, to prevent a sharp temperature drop. This complicates the use of self-priming heating.

With the onset of winter, concreting is much more difficult, and most importantly, such work requires careful preparation and full compliance with all building regulations. When pouring the foundation into frozen soil in winter, one should be prepared for the fact that in spring the earth will thaw and sag, and the foundation will crack, which will entail.

But sometimes life makes its own adjustments. The estimated time of work fails, and the foundation, which was planned to be filled in the summer, needs to be erected when the thermometer falls below zero.

You can take a chance and try to create a solid foundation for your in adverse weather conditions! The experience of the site's users suggests that with such a construction, the main thing is to arm yourself with knowledge and not let anything go by itself!

Pouring the foundation in winter

Forum user with a nickname AlecScrab the builders proposed to fill the strip foundation in the winter, in December, so that it would grab by the spring, and in March - to start raising the walls. They promised to significantly reduce the prices for their work, tk. now is not the season, and they have few orders.

Needless to say, the offer is tempting, but the forum user is haunted by the question: at sub-zero temperatures, and will this affect the strength of the strip foundation in the future.

Profanus:

- The strength of concrete takes 28 days, but this is at a "plus", and at negative temperatures, concrete may not gain strength at all.

The verdict of the forum member is as follows: pouring the foundation in winter is beneficial only to builders, because they want to make money. And for himself, he would never begin to fill the foundation in winter, even with a serious benefit.

If the air temperature during the day drops to + 5 ° C, and at night the thermometer drops below 0 ° C, then such construction conditions are considered winter.

During winter construction, the foundation must be poured using antifreeze additives and a special technology for heating concrete. And this leads to a significant increase in the cost of construction estimates. The rise in prices could completely offset the benefits of seasonal reductions in construction costs.

In the opinion 44alex, if concrete is poured in winter in compliance with all technology, then it will be cheaper, if only the workers will work completely free of charge.

The cons of the winter monolith

In the opinion of a forum member with a nickname Greenpeak, the construction of a monolithic foundation should not be carried out in winter, because:

• additional costs for concrete are required;
• special requirements for laying and curing concrete are required;
• electrical heating of concrete (or other heating) is required under constant temperature control;
• a short winter day leads to additional costs for lighting the site, insulation of the change houses for workers who are not eager to work in the cold;
• you can run into a large number of substandard materials.

Emelya:

– At first I also wanted to fill the foundation in winter, but looking at the ordeal of neighbors who filled their stove last year in December at -5 C, I changed my mind. Now they have pieces of concrete chipping off the edge of the slab and falling off. The top layer, apparently, was caught in frost, but it crumbles under the foot.

Hydration reaction

To understand what the technology of winter foundation pouring is and how much the complexity of such work increases, it is necessary to consider the processes that occur in concrete when it is poured at negative temperatures.

In the process of hardening in concrete, hydration reactions take place, during which cement minerals interact with water to form new compounds. Dehydration of concrete in the early stages can slow down or stop the hardening process and lead to a lack of strength, as well as cause its shrinkage and cracking.

At sub-zero temperatures, the water freezes before it has had time to react with cement. Therefore, the hydration reaction does not occur, which means that the concrete does not harden, and the strength of the foundation and its durability are also significantly reduced. Water frozen in concrete expands in volume, the coefficient of adhesion of concrete to reinforcement decreases, which leads to further destruction of the foundation. Therefore, the construction of a foundation in winter requires careful adherence to a complex pouring technology.

Therefore, most developers are suspicious of winter concreting. However, if you approach the matter wisely and arm yourself with the necessary knowledge, you can fill a high-quality foundation even at subzero temperatures. And sometimes it's the only way out.

How to make a basement heating shelter

The foundation of the forumchanin Svetoch - shallow tape for a house 10x10. He only managed to dig a trench and began to knit reinforcement. I wanted to pour concrete in the middle of the week (with anti-frost additives, since at night it has long been a minus). And then it turned out that forecasters promise rain and snow. The member of the forum was worried whether it was possible to leave the dug trench with formwork, partially filled with foundation and reinforcement for the winter.

Costeapechnik:

- If you leave everything as it is, the reinforcement will rust, and the base of the tape will burst! It is necessary to fill the foundation completely, and rain and snow are not an obstacle, the main thing is to take care of the concrete after pouring.

Forum user with nickname Georgespb understands how to make a shelter for pouring a foundation and what type of shelter for heating a structure is the most reliable.

motorist:

- The shelter is made like this: a large tent is erected over the perimeter of the foundation, a heat gun is installed in it, and the temperature inside rises to plus.

The required power of the gun depending on the outdoor temperature

Concrete is also heated with the help of electricity - a welding transformer connected to the armature.

For this, there are special transformers for heating concrete products: the current is supplied through electrodes placed approximately at a distance of 40-50 cm from each other in the foundation.

But this way of warming up requires special attention!

sem2005:

- An experienced craftsman is needed who will correctly install the electric heating and will monitor the maintenance of the required temperature.

With this method of heating concrete, the likelihood of electric shock to workers increases. That is why, in order to avoid accidents, it is necessary to use a 36 volt transformer. Overheating of concrete is also fraught with strong cracks, and underheating - freezing.

Antifreeze additives

For concrete with antifreeze additives, the strength by the time of its cooling to the temperature for which the additives are designed should be at least 30% of the design with a grade up to 200, 25% for concrete of grade 300 and 20% for concrete of grade 400.

For concrete without the use of antifreeze additives of monolithic structures and the monolithic part of prefabricated monolithic structures, the strength at the time of freezing should be:

• not less than 50% of the design with a concrete grade of 150,
• 40% - for concrete grades 200-300, 30% - for concrete grades 400-500,
• 70% - regardless of the grade of concrete for structures exposed to freezing and thawing.

If antifreeze additives are used, this ensures the process of cement hydration and concrete hardening, but at negative temperatures these processes are slow, and in this case, concrete gains critical strength after about a month of freezing hardening.

Concrete, which has reached critical strength by the time of freezing, acquires the required design strength only after thawing and holding at a positive temperature for at least 28 days! This means that it is necessary to maintain a positive temperature of the covered foundation not only during concreting, but also after.

Summing up, we can say that pouring the foundation in winter and at negative temperatures leads to an increase in the cost of the estimate and requires careful control at all stages of work. In return, developers get the opportunity to speed up construction work and prepare the foundation for the house ahead of time before the start of the spring construction season.

FORUMHOUSE tells you what temperature to withstand at. You can also read about.

Here you can find the most complete and detailed information about. How to fill in on what its worthy quality depends - a heated discussion of a "cold" question.

This video describes the nuances of shallow-depth reinforcement

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