At what temperature can a concrete screed be made. The quality of the solution depending on the temperature. The solutions and tools that we use to install screeds in winter
An article about pouring concrete in winter. Details on how to pour concrete and keep it at low temperatures.
Hello dear private developers! Let it be known to you that sometimes circumstances force us to conduct work in the winter. For example, a neighbor is now building a small house alone. He began last summer, work is ongoing now. To admit in the fall, I thought that he (as is usually the case) would suspend construction work until spring.
Drying the structure is cheaper than installing a screed or drying accelerator. Modern drying screed dryers usually cost as much as drying a building completely. Drying the building also prevents moisture damage, such as the formation of black mold behind furniture.
Technical drying of the structure can shorten the construction phase by weeks and months. Typically, you will get the resulting costs back when you first bill your heating. Plums for the flow of calcium sulfate can be removed after about one day, cement screeds after about 7 to 10 days of setting time.
However, the work did not stop in the fall and winter. During this time, he managed to conduct heating and is now engaged in interior decoration. But the floor screed he poured in December, not yet heating. That is, he was engaged in concrete work in winter conditions. Do you know that concrete work in winter is somewhat different from summer conditions? Let's talk today about how to carry out concrete work in the winter, in particular, how to fill the screed in winter conditions.
The solutions and tools that we use to install screeds in winter
Dry, without loss of strength or cracking in the release of the screed. Because throughout the technique. Craftsmen and architects are in demand. Using the following climate table, you can see that only about 4 weeks a year, relative humidity.
During the day, it is so small that the required drying of the building is sufficient for ventilation. Appliance - for each floor and ordinary room, a warm or tropical climate in the room changes for the best drying results of the building, we ask you for fans and heaters of our assortment. First of all, a distinction must be made.
Let us first consider how concrete behaves in the winter. We poured concrete and what begins to happen in it? At low temperatures, the water in the solution freezes, while the hardening of concrete stops. Moreover, if the hardening did not start before the water freezes, it will not continue after. At the same time, we know from the course of physics that ice is larger in volume than water, so it breaks the bonds in concrete.
Drying the building naturally by releasing moisture into the room or. Technical drying of the structure using construction drying devices. In addition, a distinction must be made between. Moisture construction caused by the production of concrete, mortar, gypsum or screed, material storage, climate condensation and condensation, as well as weathering.
Drying the building after water damage or. After the reconstruction of masonry due to increased soil moisture. Burst pipe of a water, sewer or heating pipe; defective floor heating. Flood damage; penetrating rain or condensation water.
In addition, if you reinforced the screed, ice also forms on the reinforcement and prevents the reinforcement and concrete from contacting. Concrete freezing is very harmful when the mortar is just beginning to set. It is also harmful when concrete freezes and thaws. Curing, of course, takes place, but such repeated freezing and thawing negates all work.
Defective horizontal or vertical sealing of the masonry. Type and moisture content in building materials. Humidity level of the building. The size of the surface to be dried or. Humidity inside and outside the building. In new buildings, humidity is higher than in old buildings. On the one hand, many building materials slowly release bound moisture; on the other hand, the high tightness of the new building casing in accordance with the decree on thermal insulation over old buildings means that no moisture can escape.
Let us leave physics and consider the issue from the practical side. What conditions are needed for pouring concrete in winter? In construction, there are several rules for pouring screeds in general, as well as in winter.
There are only two general requirements for concrete:
- The quality of concrete must comply with established standards, and the delivery of concrete to the destination should be without loss of quality. It would be advisable to use a concrete pump for this. As you understand, it depends on the concrete supplier.
- High-quality preparation of the site for pouring and appropriate care for the poured concrete. The builder is already responsible for this.
Already at an ambient temperature of + 5 ° С, the poured concrete significantly loses its strength. Builders struggle with this, and take measures such as:
In addition, construction processes can be better calculated. For example, fresh concrete contains from 200 to 300 liters of water per cubic meter, anhydrite floating screed with a thickness of 4 cm, about 800 liters of water per 100 m², which is equivalent to almost 200 liters of water per cubic meter; Cement strainer about 20% less.
Haircuts, like all materials associated with mineral bonds, release unbound water for mixing with the surrounding air. The drying time of the plaster and screed in a natural way can be calculated according to the rule of the thumb below, but only under optimal drying conditions.
- pouring concrete into special insulated formwork;
- the addition of various chemical additives that prevent freezing (not suitable for screed);
- insulation with infrared heat sources.
What rules should builders observe in order not to lose as a screed to be poured?
The main condition necessary for the hardening of concrete in winter is the preservation of the thermal regime, at least until the concrete has gained 70% strength. Often a concrete screed is poured in rooms where the main work is completed, that is, there is a roof and walls, but there is no heating. Therefore, it is desirable to conduct heating faster.
How long does the screed dry without technical support for drying the building? For each centimeter of screed thickness, you should expect 1 week of drying, from a centimeter to a square. For a screed thickness of 6 cm, the drying time is 8 weeks. The thickness of the screed 6 centimeters takes about 8 weeks; only 1 cm more than 13 weeks!
Even if the screed initially “rests” in the carcass, then is ventilated, and then the start-up or heating phase of underfloor heating during drying works favorably, measurements after six, often still after eight weeks, still increase humidity. This inadequate maturity leaves followers with no choice - they have to wait.
For the screed to be of high quality, it is necessary to maintain the temperature in the room at least 10 ° C heat. The main methods for providing a set of concrete strength are as follows.
- air heating using thermal curtains;
- the use of cables for electrical heating;
- covering of concrete and installation inside the heat generator.
All this is necessary to create the required microclimate for the normal hardening of the screed. You can use electric heat guns.
And the decisive advantage: it does not need to be heated for several months and years to dry the building. What about heating? Heats up without additional dehumidification of the air, it is necessary to ventilate inevitably - because humidity must go somewhere, namely from home!
The disadvantage is obvious: the incoming cold air is dry in the cold season, but it must be heated again, since only warm air can absorb moisture. And the cycle starts all over again. Result: unacceptably high heating costs! Using gas heaters, as you can see from time to time, is even more fatal. The heating process itself causes additional water retention. Therefore, stay away from such recommendations!
But providing the necessary microclimate is not the most important. It is also important to properly use the equipment for heating. There are times when an improperly installed heat gun can be harmful, for example, one area can dry out, the other freeze.
Another necessary condition is maintaining the thermal regime. It takes 4 days to gain strength with concrete at least up to 50%. All this time the room should be warm. Only if these conditions are met, you can not worry about the quality of the cast screed.
Is it possible to do without technical drying of the building in the summer? Of course, aeration, especially cross-ventilation, supports the drying process - but attention! Only if external and internal conditions are correct. Despite extensive ventilation, it still takes forever, especially the screed is dry. The reason is high humidity, which often works in the summer.
From a natural legal point of view, this makes sense: warm air can barely absorb moisture from a home, as it is saturated with water vapor. Save time and money with our professional building dryers. For each client, reducing construction time means saving money. Subsequent work can continue its work in accordance with the construction schedule. For builders, no additional rent in the old apartment and transition to a new house can be done on schedule.
If the concrete is frozen
Consider the case when you have not taken any safety measures and the concrete has frozen. What to do in this case, has the concrete really disappeared? Usually, the hardening process is restored as soon as favorable conditions arise - a positive temperature of at least 10 ° C of heat. This usually happens during autumn frosts, when it freezes at night for several days, and then a thaw sets in.
What is the minimum floor area your floor screed company does?
And simply, only a dry house is an unburdened house for the later well-being of the whole family. During a flood during which the building has been exposed to water for a long time, it takes up to 360 liters of water per cubic meter of masonry, depending on the nature. If the impregnated water during the week ranged from 5 to 10 cm in height, it could be dried for about 20-30 days in the process of technical drainage. If the basement was completely flooded, depending on the condition of the material, a period of 30 to 60 days should be planned.
Under such conditions, you should not worry about the flooded screed, such freezing will not cause significant harm. In this case, most often a thin top layer will suffer a little. When pouring screeds, the depth of concrete will not suffer completely, but only the top. Moreover, this layer subsequently crumbles.
If the irreparable happened, and your screed is frozen, you must take extreme measures to at least save something. Urgently cover the screed with a plastic film, preferably thick, so that frost and spring thaws do not completely destroy the concrete. Taking such measures, it is hoped that in the spring the process of concrete hardening will continue. Strength, of course, will be lower, but you will not lose everything, but only the top layer.
During natural drying by airing and, at best, additionally by heating, the masonry will take several months to release excess moisture into the indoor air. At this time, mold is inevitably the result. Epoxy based components.
Excellent adhesion to concrete and screed, resistant to water, mineral oil, gasoline, numerous alkaline and acidic high compressive, flexural and adhesive tensile strengths. With existing building material, fresh, not yet cured coatings may be exposed, rather than exposure to the sun, otherwise this may lead to the formation of bubbles under the pressure of water vapor. Early wetting with water can produce gray smoke. After curing, this can be partially removed by acidification with dilute hydrochloric acid. You can send or download documents by email.
These are the basic rules for pouring concrete in winter. As you can see, this is not an easy task and requires considerable knowledge. If you still have to pour concrete in the winter, like my neighbor, use the tips in this article. Good fill without loss!
If you have comments, your own experience, or suggestions for pouring concrete in the winter, welcome comments.
The substrates should be sufficiently wear-resistant, dust-free, dry, free of oil and grease, dimensionally stable and without adhesion-reducing substances. Lightly sintered, polished, glazed, cement-powder surfaces should be mechanically roughened by grinding or bead-blasting. Mixing takes place in the container of component A with a slow drill and an attached paddle mixer. During mixing, the edge and bottom areas of the container should also be recorded. After mixing in the mass there should be no stripes. Mixing time is at least 2 minutes. After mixing, pour into an empty container and mix again for 1 minute. The waiting time between two orders should be such that the first layer is still sticky when the next one has been applied. Sublimation of fresh paint in excess of quartz sand dried in the oven in excess allows a longer separation time. Subsequent work with cementitious adhesive boards usually requires grinding the final coating. Addition: quartz sand dried in an oven from 0 to 2 mm in size for a layer thickness of 10 to 50 mm, grain size from 0 to 4 mm for a layer thickness of 20 to 50 mm, grain size from 0 to 8 mm for a layer thickness of 30 up to 50 mm. Mixing ratio: 1 part resin parts: 4 parts room silica sand The binder is mixed uniformly, then an addition is added. Before soaking, rinse cracks and cuts with oil and oil-free compressed air. Cracks can be closed with a brush or by pouring wider cracks with uncut resin until the cracks and side surfaces of the brackets become wet. If the crack is wide enough, the remaining resin can be mixed with 0, 1-0, 5 mm quartz sand dried in the oven. Add refueling resin. Then sprinkle the surface with dried quartz sand in the oven from 0, 7 to 1, 2 mm.
- Immediately remove loose or exfoliating solutions and paint residues.
- Completely remove bituminous and resinous surfaces.
- Subscriptions should not be deleted if possible.
- Apply the primer evenly with a brush, coat or roller.
- Avoid the pudding.
- First, expand the cracks in the screed or concrete.
- Cutting surfaces must be dry, free of dust, oil and grease.
- Insert the clamps, if necessary, lightly add a hammer.
Our professionals always have enough solutions, methods and suggestions and we never stop working on installing floors in the winter at temperatures up to -25 ° C, we have extensive experience in this matter and we are well prepared. Here we will try to describe the basic conditions that your object should have at the time of the work and what additional measures we are taking to install a semi-dry floor screed in the winter.
Use self-alignment to solve the problem. Of course, this is possible within reasonable limits. If the floor is very curved or has large openings in it, this type of screed will not work. If it comes to easier filling and leveling, proceed smoothly by following the steps described below. This will avoid the most common mistakes made by people first creating a self-leveling screed.
What is contained in the self-leveling lintel - cement, fine sand, polymers, special additives and fillers. The polymers are designed to maintain the viscosity of the self-expanding mixture, so that it remains homogeneous if the sand aggregates do not sink to the bottom.
Dear Clients! With the onset of winter at sub-zero temperatures, many of you have a question, winter screed device, how to perform work in wet processes, namely, how is a semi-dry floor screed in the winter mechanized?
If the technological feature of this method of flooring is to prepare a cement mortar using special equipment, from the main inert materials cement + sand + water which are located outside the external circuit of the room, i.e., on the street.
Production room temperature
The main condition for the work on the screed device is the minimum room temperature + 5 ° C
Complete readiness of the premises for the installation of floor screed with the implementation of all measures, agreed levels of heights of “clean floors”, if provided by the project; installation of utilities, their crimping, laying of all networks. Installation of underlying layers of floor structures for thermal insulation, sound insulation, waterproofing. This requirement is due to the fact that downtime or unplanned interruptions for these reasons, when installing screeds in the winter, it is desirable to reduce to zero.
For insurance purposes at all facilities that our company produces between October and March, including when the daytime temperature is above + 10 ° С with a sharp decrease at night, we use the NORDPLAST antifreeze additive.
Consumption of antifrosty additives at average rates of 50 kg. cement
180-230 gr. at temperatures from + 5 ° С to 0 ° С
280-330 gr. at temperatures from 0 ° C to -5 ° C
400-430 gr. at temperatures from -5 ° C to -10 ° C
The main condition that must be observed without fail when installing a semi-dry screed in the winter is a stable, round-the-clock room temperature of at least + 5 ° C for at least 10 days from the date of work. Sources of possible cold air intake, the perimeter of prefabricated structures, stained-glass windows, entrance, openings must be mounted or closed, if the central heating in the room does not function, and the temperature is maintained / heated with the help of heaters, their provision must be constant and reliable.
For insurance against freezing screeds in cases when the room is heated by heaters, we always use anti-frost additives for cement mortars NORDPLAST.
The solutions and tools that we use to install screeds in the winter.
Depending on the production conditions, we apply: anti-frost additives, inflatable teplyaki, an increased number of links for accelerated work, rods for heating sand ..
One of such examples, you can see how our company completed the construction of the Solutions office center on ul. Kirovogradskaya d.23 At this facility, our company performed work in the month of January at a temperature of -5-10 ° C.
The floor area is 2,300 sq. M and the layer thickness is 10 cm. It was completed in 4 days with the involvement of 3 teams. Another example, winter - floor leveling at the Akura TechCenter dealership
One of our best and least costly methods for winter period used by us on large-area facilities such as shopping centers, office rooms, shops, when the area of \u200b\u200bthe room where the semi-dry screed is required is vacated and fully prepared for leveling the floor, we use several sets of equipment and links for quick consumption of sand so that it does not have time to freeze. Restriction on air temperature no more than -10 ° С
Sand is delivered to the object, as needed, in small batches in a heated heavy truck body of 10-20 m³ each, based on its total consumption during a couple of hours in freezing weather. The volume of sown sand of 20 m³ is processed in no more than 2 hours by three links.
