Why does concrete crack after pouring the foundation? Why does concrete crack after pouring? If the cracks are not through

Rules of care

To prevent concrete from cracking after pouring, it is necessary to provide it with appropriate care, which is a set of measures that promote a favorable curing regime for the composition until it reaches operational strength. Neglecting these measures can cause deformation of the massif, reduce the rate of strength gain, and cause a violation of integrity.

A set of measures aimed at achieving the grade strength of concrete and ensuring integrity consists of performing the following tasks:

• ensuring minimal shrinkage of the poured composition;

preventing accelerated drying of the mixture;

• neutralization of temperature changes;
• prevention of mechanical stress and the influence of chemical reagents.

Compliance with these requirements will ensure an increased service life of concrete, which will have high strength.

When pouring concrete, remember to follow these recommendations:

• Begin maintenance work for the freshly poured mixture immediately after concreting and ensure that the mass reaches at least 80% of its operational strength until it reaches at least 80%.
• Check the integrity of the formwork, the absence of leaks, or breakages of the wooden structure immediately after concreting. Correct defects within 2 hours after pouring the solution, before the concrete begins to set.

When mixing the mixture, you need to follow the recipe and strictly observe the proportions between its components.

How to avoid

Wet the wall with a clean brush moistened with water
. To eliminate the first reason, it is enough to moisten the working surface with a brush with water before applying the solution. This will remove any existing dust, increasing the adhesion of the plaster. Applied to a clean surface it will last for a long time.

Mixtures of sand and cement must be applied in layers, forming the required coating thickness several times. This important technological condition must also be observed for thin layers. Otherwise they will start to crack.

Reinforcing mesh reduces the risk of cracks

It is imperative to create a primer layer on the surface to be finished. When the solution dries, it shrinks, changes structure, and cracks. It is covered with a finishing layer on top and rubbed .

The absence of a reinforcing mesh under some circumstances (moving base) contributes to the surface cracking. Reinforcement is performed with metal, fiberglass, and plastic materials. The use of one or another type is determined by the possible degree of risk of destruction and the thickness of the coating. The mesh protects against negative mechanical influences.

This is a multicomponent composition that includes various substances in the correct proportions. To obtain high-quality working material, it is necessary to thoroughly mix it with water until it becomes a homogeneous mass of the desired consistency. For more information about the causes of cracks, watch this video:

The optimal ratio of cement to other components of the mixture is one to three. This means that per unit of its mass there are three mass parts of sand, polymer and modifying impurities.

Exceeding the proportion of cement leads to cracking of the plastered surfaces.

The main causes of cracking and methods for their removal should be presented in table form.

Elementary disregard for manufacturers' recommendations explains why plaster cracks when it dries.
Negative processes in most cases are caused by irresponsibility during work. The appearance of cracks requires their immediate elimination. The modern building materials market offers a wide selection of finishing products that allow you to cladding the facade of a house or interior walls in an original and high-quality manner. In this article we will look at the features of plastering walls with clay with detailed instructions for preparing the solution and applying it to the surface.

Advantages and disadvantages of clay plaster

Clay plaster is considered an environmentally friendly and natural material that has been used in construction since ancient times. The practical use of plaster will provide a beautiful design for the room. Walls plastered with clay will breathe without releasing harmful substances into the air. Moreover, this material is not harmful, unlike other putty solutions made on the basis of polymers and other synthetic substances.

Previously, plastering walls in this way was the only option for finishing work. Despite the fact that modern manufacturers offer a wide selection of different solutions, many buyers still prefer to use natural materials. Plastering a house with clay has many advantages, which will be described below:

• Eco-friendly and natural product.
• Clay mortar is capable of absorbing moisture, which will prevent walls from collapsing.
• Low cost of materials compared to other types of products.
• After using the solution, there is practically no waste left, and the remaining clay can be reused.
• Ease of preparation of the mixture.
• Clay for plastering walls will protect the surface from mechanical and other influences.
• The material is elastic in its structure.
• Clay can be used for finishing work indoors and for the facade.
• Technologies for applying clay will allow you to create an original decorative pattern on the walls, and adding paint will create a certain shade.

Clay plastering has its drawbacks, which are determined by the following parameters:

1. Natural clay, which does not have various additives, is a unique material that requires experience to work with. When preparing a solution, the main thing is to correctly calculate all the components, because there is no specific recipe for making the mixture.

2. Plastering the facade of a house is not an easy task. It is important to consider that clay absorbs all moisture well, which is why small cracks appear from time to time around the perimeter of the building. Thus, clay walls will need to be renewed every year.

3. Recently, there are not many craftsmen who would professionally plaster walls with clay, and therefore paying workers can be expensive.

Most hardware stores offer a wide range of products, and on the shelves you can see decorative clay, as well as mixtures of different shades and variations. The physical and other characteristics of the clay are usually indicated on the packaging, and manufacturers also provide short instructions for use. In fact, it is not necessary to purchase clay in its natural form, because you can buy a prepared mixture, which will make the work process easier for a beginner.

It is important to know! If you decide to choose natural clay for your summer cottage or other places, you need to remember that using the material without special additives can cause the plaster to crack when exposed to moisture or active sunlight.

Clay plaster: composition and types of mortar

To preserve the properties and the original layer of clay, many advise applying a layer of plaster over the clay base of the wall. This will strengthen the finish or facade of the building, as well as protect the material from excess moisture and the like. But, most specialists use only clay mortar, the preparation technology of which has the following sequence:

• sand;
• clay;
• water;
• sawdust from wood or other type of material.

It is worth knowing that sawdust of various kinds, as well as different fibers, are added to the clay so that the solution is held together and cohesive. This will help prevent cracking of the wall surface under the influence of the sun or other natural factors.

Clay mortar for plaster can be divided into several types, depending on the materials added to the mixture. So, there are these types of plaster mixture:

• solution with added sand;
• mixture with sawdust from different tree species;
• a combination with the addition of the two previous components.

In certain situations, when it is important to create a high-quality mixture for finishing the facade of a building, you need to add cement or putty. These materials will help hold the solution together. Before starting finishing work, it is important to calculate the climatic zone of the house. This is explained by the fact that clay is a heat-insulating layer. Before starting work on plastering with clay and sawdust, it is necessary to study the characteristics and features of the surface being treated.

Technology for preparing clay plaster

When preparing the solution, you need to know that the addition of synthetic fibers is recommended for rough finishing of walls or for forming an insulating layer. You can add cement or sand to the plaster, which will reduce the elasticity of the mixture and also help retain heat in the thickness of the walls.

It is recommended to apply a clay solution for plastering walls when the insulation layer has already been installed in the room. The main positive property of clay is that it is excellent for adhesion to other materials, for example, wood, stone, cement or concrete. To prepare a clay solution you will need the following equipment:

• a vessel for mixing the mixture;
• bayonet shovel;
• screwdriver;
• a set of spatulas for applying and distributing clay over the surface;
• a large sieve for sifting various components that are added to the mixture;
• drill with additional attachment for mixer;
• To attach the metal mesh you will need a hammer drill.

Also, to prepare the solution you will need different materials, which are:

• metal mesh that will be used to reinforce the wall surface;
• clay;
• additional fibers or sawdust, which depends on the type of work;
• dowels that will attach the mesh to the wall surface.

After preparing the necessary tools, devices, and materials, you can begin preparing the mixture. Many people are interested in the question: how to dilute clay for plaster? As a rule, the technology of work depends on the type of clay, which may differ in different parameters. However, there is no specific procedure for stirring the clay and preparing the solution. However, when performing work, you must adhere to the sequence, which determines the quality of the mixture produced:

1. First you need to prepare all the components used in the work.

2. After this, the clay is soaked in water and left for a day.

3. After the time has passed, the wet mixture must be mixed again and excess water removed from the container.

4. It is important to sift various fibers, sawdust, and sand through a sieve.

5. After cleaning the additional components, they are added to the clay along with water, and all components are thoroughly mixed.

6. The prepared mixture should have a thick and sticky consistency, and the proportion of clay and sand for plaster should be 1:2 or 1:5.

After completing this work, the mixture becomes ready for use. If the composition of the solution is too sticky, then to remove this property you need to add a little sand. The prepared mixture can be tested for plasticity using several methods:

• Visually, the clay mixture should resemble the appearance of thick sour cream.
• You can also make a small ball. It must be pressed against a solid base, creating a plane 1 cm thick. If all components are mixed correctly, then the pressed edges of the ball should not crack.

Another option for checking the plasticity of the solution is the following procedure. To do this, you need to create a ball, after which it is dropped to the floor from a height of one and a half meters. The net effect should be that the ball should not crack.

On a note! If the ball cracks in one of the ductility testing methods, this may indicate an overabundance of sand. If the ball has spread, this is indicated by the presence of a large amount of water in the solution. All shortcomings can be easily corrected by adding the necessary components to the mixture and mixing them.

Step-by-step instructions for plastering with clay

The technology for working with clay is reminiscent of the method of applying cement mortar. To prepare the solution, the main components of the plaster are: sand, clay, cement, which can be added to hold the mixture together. When carrying out work, you should adhere to the following instructions:

1. First, attach the mesh and metal to the working area using dowels. This is important for reliable application of the solution.

2. Using a spatula, the solution is applied to the wall surface. The thickness of the clay layer should be no more than 5 cm. This layer is rough and does not need leveling.

3. After applying the first layer, you need to wait until it is completely dry, after which you can begin further finishing.

4. When the rough surface has dried, you need to clean it and sand it using sandpaper.

5. The last and final stage of applying plaster is the finishing coating of the wall surface.

Plastering walls with clay is an excellent solution for insulating and finishing a country house. This option of applying plaster is perfect for a rustic style or the design of houses made of logs or wood, which will ensure the environmental friendliness of the building. As decoration, you can use volumetric embossing or clay modeling technology. To protect the wall surface from external influences, you can paint the clay with paints and varnishes of different shades.

Recommendations from experts on applying a clay plaster layer

Experts in the field of plastering houses advise adhering to some recommendations for carrying out work. For example, it is not recommended to start finishing work immediately after building a house. Otherwise, the house will still succumb to sedimentation, causing the plaster on the walls to crack. The approximate settlement period for a house is 1.5-2 years for wooden or brick structures. A building constructed from foam concrete or aerated concrete has a lower load, which determines the settlement period of 4-6 months.

After the erected house has stood, you can begin plastering with clay, video of the work, which can be seen at the end of the article. First, it is important to do the interior decoration of the room, and lastly, you need to start external work. This point is explained by thermal and physical parameters and the peculiarities of finishing. This will prevent cracking of the plaster layer from exposure to steam.

Before plastering, you need to prepare the walls. First of all, they must be even. After all, with an uneven surface, the layer of clay in different places will be different, which is not very good. In this case, the layer of plaster will be thicker, which is not very favorable, because the standard layer thickness should be up to 2 cm. With a large thickness of clay plaster, it will begin to crack and fall off over time. Also, a layer of 4 or 5 mm plaster is also not recommended, otherwise the mixture will not stick to the wall.

When applying the plaster layer, you need to remember about the adhesion of the mortar to the wall. To do this, the surface is pre-moistened with water, after which plaster can be applied. This will create a reliable connection between the finish and the wall. At the same time, clay can be applied to the surface not immediately, but in thin layers. This will allow the building material to bond better, which will extend the life of the clay plaster layer.

The technology of plastering walls with clay is not labor-intensive, however, it requires some care when preparing the solution and applying it to the wall surface. All work can be done with your own hands, the main thing is to follow the recommendations of specialists and step-by-step instructions for the expected result of the work.

Peeling and cracking of plaster occurs for various reasons. Let's look at common factors that influence this process, and also give recommendations for eliminating these damages.

Restoration technology for façade and interior plastered walls

External and internal finishing of permanent buildings involves applying plaster to the walls.
It can be different: façade, rough, decorative. Alas, even the best quality work does not guarantee peeling and cracking. Defects on plastered surfaces appear as a result of flaws in construction, the negative impact of atmospheric phenomena, and improper operation. What to do if the finish falls off the walls, peels off, or cracks. Let's look at common defects and methods for eliminating them through partial repairs.

Peeling, swelling of the coating
The reasons for this phenomenon can be different: poor-quality composition of the lower layer, violation of application technology, low strength of the first layer.
Repair of such areas begins with tapping the wall. The dull sound guarantees the strength of the bottom covering and there will be no problems here. If tapping responds with a ringing tone, this indicates the presence of voids and the prospect of destruction of the layer. It is also advisable to include these places in the renovation. Swollen areas must first be cleared of the upper deformed layer. The tool used depends on the condition and type of plaster: trowel, chisel, hammer. After cleaning the wooden walls, the strength of the lower layer of shingles is checked. On concrete, brick, and stone surfaces, defects in the form of chips and large chips are removed, notches are made and cleaned with metal brushes. After these procedures, a primer is applied, and then a new coating.

Cracks in plaster
There are many reasons for cracks in the wall.
The main one is the error when mixing the finishing solution. It is also possible that drying occurred too quickly or there was an excess of astringent in the solution. For small cracks, the damaged area is rubbed with a gypsum mixture. Deep ones need to be eliminated differently: they are first widened, cleaned, moistened and then sealed with prepared, well-mixed plaster.

The finish is crumbling. What to do?

Collapse of plaster occurs due to high humidity, improper application of the solution to the surface, or poor-quality mixture. The possibility of shedding can be prevented. If the room has high humidity, you need to eliminate the causes: remove leaks, adjust ventilation.

The damaged area must be cleaned of the old layer and dried. After drying, the repair area should be treated with an antifungal agent and a new layer should be created. If you want to finish a wall with increased strength, use a reinforcing mesh; it will eliminate the possibility of crumbling.

How to avoid cracks after drying plaster

Lack of experience, neglect of recommendations for plastering work and non-compliance with the manufacturer’s instructions for working with materials lead to the creation of low-quality coating.
Most often, this is what leads to a violation of integrity. Knowledge of the technology and rules for applying the solution will help to create a high-quality coating and avoid cracking. Reasons for violation of surface integrity:

Low quality of the composition, the proportion of cement in the solution does not exceed a third; The base for application must be strong. Otherwise, when drying, shrinkage may occur, which will lead to cracking; the mixture is always applied to the primer in layers, and the first layer should be the strongest; the presence of unmixed lumps of dry cement/sand in the solution during application forms cavities that form cracks when dry; applying too thick a layer (2 cm or more), poor drying between layers; absence of a reinforced layer (construction mesh); unprepared surface, presence of chips, cracks; excess moisture in the composition, failure to comply with the proportions when diluting the dry mixture. Excess water weakens the structure of the plaster, reducing adhesion.

Technology for repairing decorative plaster walls

The decorative effect of the plaster adds texture.
For interior spaces, various plastering methods are used, which are divided into types: Venetian, structural, marmorine, silk. For the facade: bark beetle, lamb, stone, Venetian with marble chips. Repairing such a coating is more difficult. Let's look at the sequence of work with Venetian finishing. 1. The decorative layer of the damaged area is completely removed. 2. The surface is cleaned. 3. The adjacent edges are lubricated with an aqueous solution of PVA glue. 4. The area to be repaired is covered with a base layer, then with plaster until the required thickness is completely restored. 5. Adding texture, coloring. Cracking plaster is a very unpleasant situation. Cracked plaster sharply loses its strength and looks unsightly, and it is better not to finish a wall covered with such plaster - the coating will not adhere properly, and the plaster will continue to crack and crumble. Therefore, it should be prevented even at the plastering stage, and in this article we will look at how to prevent such cases from occurring.

Recommendations for eliminating cracks

Cracks in concrete that appear within two hours after pouring can be easily repaired using additional vibration compaction.

Cracking that occurred after setting is eliminated by rubbing in a special composition for repairing defects in a concrete surface or a cement solution prepared in a 3:1 ratio (cement-water) with the addition of a special plasticizer or sealant.

If, within 8 hours after pouring the composition, signs of integrity damage appear on the surface, eliminate them by following the sequence of operations:

• clean the surface of deposits using a metal brush and, using foam glass, wipe away defects;
• blow off dust from the surface with a stream of air;
• use a repair mixture to fill defects in the array;
• After the repair compound has hardened, re-grind the surface.

If the crack is through-through in nature, then its repair is carried out in the following way:

• Clean the cracked area.
• Increase the width of the crack.
• Clean the exposed defect by removing dust, particles of the array, using compressed air or a brush.

If cracks do appear, you need to carry out work to eliminate them as quickly as possible.

If defects occur in the concrete mass, which arose under the influence of groundwater, cracks are eliminated using special waterproofing compounds.

Crack repair

Repairing cracks with special care

No matter how strong the screed is, during operation or due to violation of the coating technology, various defects may appear on it: cracks, potholes, pits.

This can be discovered after the old coating has been removed.

Why the floor screed cracks, how to fix it yourself without calling specialists - this worries everyone who has decided to replace the old floor covering with a new one.

The following tools will help you make repairs: a hammer drill, a hammer, a grinder, a hacksaw, a marker, a metal rod with a diameter of 12 mm, and a construction syringe.

To seal cracks, you need to stock up on epoxy resin for concrete, quartz sand, primer and repair compound. There are separate repair recommendations for different sizes of cracks.

small crack

First of all, you need to clean the area where the defect is supposed to be eliminated. Here you should widen the crack with a chisel and hammer to a depth of 1 cm. The crack should look like a groove, narrowed at the bottom.

Clean the area and remove dust from it with a vacuum cleaner or sandblaster. The entire prepared surface is treated with epoxy resin mixed with solvent in a ratio of 1:10.

After work, the surface is allowed to dry. This is required for the strength of the bond between the repair mortar and the base. Then you need to fill the crack with a solution, let it dry, clean and sand.

Large crack

The order of actions is presented as a list:

• Prepare the area for repair and use a grinder to deepen the crack to 5 cm.
• Then you need to make deep grooves on both sides of the crack and use a chisel to gouge out all the concrete.
• Remove dust and coat with epoxy resin solution.
• Since the crack is large, the repair solution is applied in several passes.

To repair large cracks, metal staples are used: make cuts across the recess 1.5 cm wide and 2 cm deep, put the repair solution and the staple into them.

Fill the entire crack with mortar in this way, let it dry, clean and sand.

Pothole Repair

Initially, use a grinder to clean out the pothole to a depth of 2 cm. Concrete is removed from the cavity using a hammer drill, after which it is necessary to remove dust. Next, prime the pothole with epoxy resin.

After the primer has dried, you can fill the pothole with repair mortar and level it with the floor. After the solution has hardened, it is cleaned and sanded.

Repair of coiled areas

The section of the screed that is movable under load is called the bouncing section. Repair of such areas begins with removing the coating until the surface is in a stable condition.

Having removed the coiled fragments, you can carefully examine the concrete base underneath - there may be a fault on it. Next, you should remove moving areas on the concrete floor, dust and prime everything.

After the primer has dried, fill the crack with a material similar to concrete and allow it to dry. Repairing a pothole begins by removing debris and dust, then priming it and allowing it to dry.

Subsequently, the movable section of the screed is re-filled with a cement-sand mixture, and the solution is leveled flush with the floor with a wide spatula.

Repair of movable screed by injections

Injection is the most progressive method

Spilling areas can be strengthened using injections.

To do this, you must first determine the area of ​​detachment and mark it with a marker.

Using a drill or hammer drill, drill holes with a diameter of 7-10 mm and at a distance of 25 mm.

Fill a construction syringe with low-viscosity epoxy resin and fill all holes.

Let the resin dry and go through all the holes again with a syringe.

Gradual filling with repair compound gives time for the concrete to soak and fill the peeling area completely.

As soon as the level of epoxy resin in the holes stops decreasing, stop pouring.

The resin will harden within 24 hours, so it is better not to walk on the site.

It is important to know that if the area with defects makes up more than 30% of the area, then the screed must be completely replaced. Repairing and filling do not require much skill, the actions are simple and can be done even by beginners in construction. The main thing is to adhere to all the rules and recommendations for filling.

Learn more about screed repair in the video:

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Causes of cracks in concrete after pouring and ways to eliminate them

Sometimes after pouring or after a certain period of operation of a building or structure, cracks appear in the concrete. There are many reasons why concrete cracks after pouring. Such defects arise for various technological and operational reasons - due to violations of technology, non-compliance with proportions when mixing the solution, and the service life of the structure. Cracking of concrete negatively affects the load-bearing capacity of structures. When cracks appear, it is necessary to take a number of measures to eliminate them, although it will not be possible to completely remove them.

How to coat a stove

Cracks cannot simply be repaired with plaster or other material; all defects must be identified and restored correctly. You should not skimp on such work, as this can lead to even greater defects. The entire process of restoring the furnace lining includes the following steps:

• inspection and determination of the causes of defects;
• selection and mixing of the solution;
• applying grout and plaster.

In most cases, the actions will not take much time, and most importantly, they will not allow carbon dioxide and combustion products to accumulate in the room.

What to do with cracked concrete

When cracking has already appeared, it is necessary to take immediate action, because Such processes reduce the strength of the building, deteriorate its appearance, reduce its service life, and negatively affect the susceptibility of various loads. After pouring, water begins to enter cracks in the concrete, saturating the material and penetrating to the metal reinforcement. Due to moisture inside the concrete structure, it begins to rust and tear the material from the inside.

Building codes and regulations (SNiP) allow the presence of cracks up to 0.1 mm, formed as a result of temperature changes during freezing and thawing. To eliminate defects, the first step is to understand the reason for their occurrence.

If cracking occurs, you can use the following options for eliminating defects:

• Injection of cracks in concrete after filling with special repair compounds. The solution is injected under pressure and requires qualifications and the use of special equipment.
• Sealing the cavity. Before sealing, the fracture is opened up to 5 mm, and crumbling areas are removed. The cavity is filled with a solution consisting of sand, cement, and polymer fillers. Thus, the fracture is sealed and sealed, eliminating the possibility of repeated cracking.

If concrete cracks after pouring, there are various options for repairing the resulting defects. They are selected depending on the type of concrete structure, the magnitude of the loads experienced, the nature and causes of cracks. The repair composition is selected taking into account the brand and type of concrete (the best option is the composition as close as possible to the base material).

Repairing small cracks

In addition to wide and deep cracks, thin defects, the width of which is 1-3 millimeters, often appear on the plastered surface. To eliminate them, it is hardly worth resorting to “heavy artillery” and embroidering the edges with a chisel. It is also not advisable to purchase the mixture in a bag, from which you will hardly have to use more than 100-200 grams of material. To work with such damage, it is better to purchase acrylic in a tube designed to work with a special gun. Acrylic is a universal material, perfectly compatible with most finishing materials, durable and moisture-resistant. In addition, the polymer has another important property - even when completely dry, it retains elasticity and reliably fixes the crack even in cases where the coating is subjected to mechanical stress such as vibrations or shocks.

Small cracks must be cleaned of dust and other contaminants using a brush and vacuum cleaner and must be primed. After this, we fill the voids with acrylic, also making sure that they are completely filled with the material, and smooth it with a narrow rubber spatula. Acrylic, unlike dry plaster mixtures for repairs, hardens very quickly and the wall treated with it can be finished after 3-4 hours.

Finally, I would like to remind you once again that when eliminating wall cracks, not only the cosmetic aspect is important - in most cases, an important role is played by determining the cause of the problem, which may turn out to be more serious than it seems and lead to further destruction of the coating and its base.

Useful tips

Violation of technical rules and regulations during plastering work and preparation of mortars leads to the appearance of various types of defects in the plaster: cracks, dents, peeling. Cracks in plaster. Causes. Photo.

Cracks in plaster

Cracks in plaster can also appear as a result of the use of thawed mortars; no more than 10% of the thawed mortar can be added to a freshly prepared mortar. The applied plaster must be protected from rapid drying and drafts by closing windows and doors in plastered rooms. In hot or windy weather, it is recommended to cover the plaster on facades with wet matting or frequently water it with water.

Causes of cracks on the surface of plaster.

• The surface is poorly prepared, the plaster has partially moved away from the base.
• Fatty solutions (with a high content of astringents) are used.
• Poorly mixed solutions.
• Dries quickly when exposed to drafts or high temperatures.
• Too much layer applied at one time.

Treshnny, definitely aimed

, are formed on wooden or brick surfaces: on wooden ones - along the cells of stuffed shingles, on brick ones - along the seams of the masonry. On wooden surfaces, this happens because a too thin layer of mortar is applied to them or a very wide shingle is filled in, which warps under the layer of plaster and tears it. To prevent cracks from appearing, shingles should be used no wider than 2 cm. The thickness of the plaster layer on wooden surfaces should be at least 15 mm, counting from the level of the exit shingles.

Cracks on brick walls appear as a result of applying very thin layers of plaster without first wetting the surfaces with water. The reason for the formation of cracks may be alkali released from the masonry joints.

Peeling plaster

Peeling of plaster Peeling and subsequent cracking of plaster occurs regardless of the composition of the solution.
This is caused by the fact that the mortar was applied to a dry surface or to dried layers of a previously applied mortar. Peeling can also occur as a result of the fact that subsequent layers of mortar were applied to weaker previous ones, for example, a stronger cement mortar was applied to lime mortar.

The plaster also peels off and cracks if lime or lime-gypsum mortar without transition layers is applied to the concrete base or cement plaster. To avoid peeling, concrete surfaces should first be sprayed with cement, then with complex, i.e., lime-cement mortar, and then plastered with lime mortar.

Dutik

Dutik This is a small bump that appears on the surface of the plaster;
crumbles easily, leaving a white or yellowish spot in the center. Ducts are formed because the solution was prepared with unseasoned lime, in which small particles were not quenched. Once in the plaster, they begin to extinguish after some time and increase in volume. The suppression can last for quite a long time, sometimes for years. To avoid dummies, freshly slaked or slightly aged lime dough used to prepare the solution must be strained through a sieve with holes of 0.6 mm or 0.5X0.5 mm. Textbook Plastering work. Shepelev.A.M.

The appearance of various kinds of cracks on the walls or ceilings is possible not only in old houses with already worn-out and weakened finishing, but also in completely new apartments where finishing work was carried out quite recently.

Many, seeing such defects in their own home, begin to panic and come up with many different reasons that can explain this phenomenon. In most cases, the owners scold the finishing craftsmen with all their might, or if the work was carried out on their own, they begin to scold themselves and decide never to take on plastering work on their own again.

But the master is not always to blame for the appearance of such defects. In addition, in the modern construction industry there are many different materials that are designed specifically to eliminate such troubles.

Cracks in concrete

Concrete cracks for various technological and operational reasons.

Varieties

• Constructive. In such cases, concrete cracks when drying due to increased loads resulting from design errors, the use of low-quality or unsuitable grades of cement, non-compliance with the rules of operation of the building, etc.
• Unconstructive. Violations of the pouring and drying technology, unfavorable conditions for crystallization of the concrete mass after pouring contribute to the appearance of this type of cracks.
• Arising from fires. Under the influence of high temperatures, the hardened mass begins to delaminate due to the expansion of metal reinforcement and the difference between the internal and external layers of the concrete mass.

• Consequences of plastic shrinkage. They arise due to the high speed of concrete drying during the pouring process, are almost invisible in appearance, have a thickness of several microns, and a length of up to 750 mm.
• Consequences of temperature shrinkage. At high air temperatures, concrete crystallizes with the appearance of strong stresses that destroy the top layer. The rupture occurs from the outside in. Such a defect can have a width from tenths of a millimeter to several centimeters.
• Corrosion. Such cracks in concrete when drying appear due to rusting of reinforcing bars, which are located close to the surface. They appear several months after the start of operation and arise due to violations in the pouring technology or the selection of an incorrect wall reinforcement scheme.

Determining the causes of concrete cracking allows you to select optimal measures to eliminate defects.

Causes

• Soil subsidence or swelling.
• Increased soil moisture, which causes it to rise.
• Soil compression caused by drainage systems.
• Failure to comply with the rules for installing formwork or calculation errors (optimal cross-section, location points of steel rods, etc.).
• Premature loads on the concrete mass before it has reached serviceable strength.
• Poor quality compaction, in which air cavities are formed in the concrete mass.
• Opening of cracks after drying sometimes occurs due to failure to maintain the required time when preparing the solution.
• Severe corrosion of reinforcing bars that are located inside the monolithic mass.
• Shrinkage processes and temperature effects that occur at the initial and final stages of hardening of the concrete solution.
• Cataclysms, man-made disasters.

The reasons why concrete cracks when drying may be shears acting diagonally to the longitudinal axes of the reinforcement. Stresses that stretch the structure cause deformations that occur along the axis of the rod or parallel to it. If violations were made during the installation of the reinforcing mesh before pouring, then peeling of the protective layer may occur at the corners of the strip foundation.

Materials for sealing defects

To eliminate cracks on different surfaces, several types of materials are used such as:

• Carpenter's glue. It is diluted to a liquid consistency and chalk powder is added. The composition is applied to the damaged surface, and the excess is removed, since after drying it hardens greatly;
• Pieces of cotton cloth, gauze or bandage. Before sealing the area, it is first cleaned, a thin layer of ordinary silicate PVA glue is applied to it and the required size of fabric is glued. Several more layers of glue are applied on top of the fabric after the previous one has completely dried;

• Paint solution with cement. Ordinary cement is poured into the paint in small portions, constantly stirring with a wooden stick. The mixture is brought to the state of liquid sour cream and the defect is painted over in several layers. This composition is considered waterproof and can be used in the exterior of the finish;
• Cement-lime mixture. This composition is used when deep cracks occur on a wall made of brick, stone or concrete. The damaged area is cleared of the previous finishing materials, before filling the gap, a metal mesh is installed and, if necessary, secured with dowels, then a cement-lime mortar is applied and, after it has completely dried, plastering is carried out.

Separation of cracks into groups

Determining why concrete cracks when drying is necessary in order to select the most appropriate method for eliminating defects that have arisen.

Constructive

If significant cracks appear in the concrete after pouring, this may be due to serious errors in design calculations. These are dangerous defects that reduce the strength characteristics of a building or structure. Concrete also cracks under the influence of gravity due to poor quality material and non-compliance with operating rules.

Non-structural structural

The reasons why concrete cracked after pouring can also be plastic shrinkage, reduction of material during the drying process, rusting of reinforcement, and temperature-shrinkage factors.

Causes of faults

Before starting restoration work, it is necessary to determine the reason why the destruction began. If these actions are neglected, even after repair the foundation will gradually collapse. The causes of destruction can be divided into several groups:

1. Technological. An example is the creation of the foundation of a house with violations of reinforcement or installation of formwork. Mistakes also include choosing the wrong brand of concrete. Laying the foundation above the groundwater level is also considered a technological error.
2. Operational. Such mistakes are made already in the process of using the constructed structure. For example, an increase in the load on the foundation as a result of the creation of a second floor. Another violation is an increase in humidity in the basement or poor-quality installation of a drainage system near the house.
3. Structural. An example is the preparation of incorrect calculations during the design of a structure. Often the foundation begins to collapse prematurely due to the fact that geological studies were not carried out before construction began.

Important! In order to avoid encountering the problem described, before building a house, it is necessary to accurately calculate the load on the foundation.

Plastic shrinkage cracking

The reason why concrete cracked after pouring may be plastic shrinkage. There are different types of such subsidence defects.

Surface deformations

Concrete after pouring may crack when drying due to the rapid evaporation of water in the solution. Surface damage occurs due to a mismatch between the rate of evaporation and the rise of moisture. After pouring, small hairline cracks form in the surface layers of the concrete mass. If there are few cracks and they are small, you can not attach importance to them. But various external factors can widen the rifts.

Subsidence defects

The reason why cement cracks may also be the appearance of resistance in the concrete mass during settlement. Shrinkage of concrete after pouring begins when the mass hardens and compacts, and at this time there is a possibility of cracks up to 25 mm deep. In some cases, the splits reach the reinforcement and expand within the mass. To prevent concrete from cracking after pouring, it is necessary to correctly select the components of the solution and compact the mass after pouring.

What to do when repairing large defects in plaster

To properly repair the damage, you must know what to do and what tool to use. To work you will need:

• paint brush;
• brush;
• gypsum-based solution;
• small spatula;
• sandpaper and metal brush.

The sequence of actions during repair work will be as follows:

• clean the crack from debris and dust;
• using a brush or brush, moisten the surface with ordinary fresh water;
• prepare a gypsum mixture for external walls, and lime mixture for internal premises;
• using a spatula, fill the damaged area with the solution;
• After the mixture has dried, smooth the surface with sandpaper.

What to do when sealing spider web cracks in plaster

Small cracks, which have several branches in different directions, look like a spider’s web, hence their characteristic name. Such damage is quite dangerous because it can spread at high speed and is caused by non-compliance with the technology for applying the finishing material.

To eliminate them you will need the following tools:

• fiberglass (especially for sealing such surface defects);
• wide spatula;
• primer mixture;
• brush for applying primer and cleaning the surface;
• gypsum, lime or cement putty (depending on the finishing material);
• sandpaper and grout mesh.

The sequence of actions for elimination will be as follows:

• clean the damaged area from finishing material (wallpaper, paint);
• prime the surface in two layers;
• apply a thin layer of putty and glue the fiberglass mesh onto it;
• Apply another layer of putty on top of the mesh, you can wait until the bottom layer hardens a little;
• After the putty has dried, rub the surface.

It is important that the fiberglass mesh covers the damaged area with a small margin of a few centimeters.

As you can see, the appearance of cracks on any surface can be easily eliminated if you have a special tool, the necessary materials and theoretical knowledge.

The beauty of any building, both inside and outside, largely depends on the perception of the walls. These surfaces occupy the largest area and are constantly exposed to destructive factors. What to do if the finishing on the outside or inside of the house is damaged? What caused the destruction?

In this article, we will look at why plaster cracks, peels, or crumbles, and we will also give recommendations on how to repair these damages yourself.

Other types of cracks

Temperature shrinkage

When mixing the solution, a chemical reaction begins between water and cement, heat begins to be released and the temperature of the mixture rises. In such cases, when the mass settles, it may be additionally affected by the sun, ambient temperature, and other factors. Internal processes are also affected by the brand of cement, reinforcement material, etc.

Shrink when dry

What to do if concrete cracks when drying? The reason why concrete cracked after pouring may be a violation of the composition of the solution during pouring. Because of this, shrinkage defects appear - as a rule, in structural elements without reinforcement. Concrete can also crack from exposure to the external environment - rain, snowfall, flooding, groundwater. Such factors can cause sudden shrinkage and fractures.

Advantages and disadvantages of clay compositions

Fireclay clay

Fireclay clay
The following features are highlighted as advantages:

• clay is a natural and environmentally friendly product;
• solutions perfectly absorb water and release it, which prolongs the service life of coatings;
• reasonable cost;
• the remains of the used solution are stored for a long time;
• the material perfectly protects the surface from mechanical impacts;
• the elasticity of the material allows it to be applied without any problems;
• Not only internal, but also external surfaces are finished with a clay mixture;
• using the solution, level and decorate the surfaces.

In addition to the positive aspects, clay-based plaster has a number of disadvantages, which explain most cases why clay cracks:

• There is no exact recipe for preparing the solution; craftsmen prepare the mixture using their own experience;
• there is a possibility that the surface will become covered with cracks;
• Such compositions are rarely used; there are few experienced craftsmen who know how to cover a stove with clay so that it does not crack.

Defect Prevention

What to do if concrete cracks after pouring? A number of measures must be taken to prevent cracking. Often cracks in fresh concrete can occur due to water imbalance. Therefore, when preparing the solution, it is necessary to strictly observe the proportions so that there is no excess water. At cold temperatures (below °C), moisture begins to freeze and expand, concrete cracks and crumbles, and reinforcing bars are exposed. The cracking processes begin to be aggravated by corrosion of metal rods.

Why are cracks dangerous?

If the foundation of a building is cracked, work must begin immediately to restore it. If this is not done, after a while, due to the skew of the house, the doors and windows will begin to jam. If the house is made of brick, the crack may spread to the wall, causing the entire structure to begin to collapse. That is why it is necessary to begin work on strengthening the foundation as soon as possible.

Before starting restoration work, it is worth determining the type of crack. To do this, just clean it from dust and rinse with water. After this, you need to install a beacon on the fault. The date of fixation is marked on it. This is necessary to determine the rate of destruction of the base. If the lighthouse remains intact within two weeks, the crack can simply be sealed with concrete mortar. If the lighthouse breaks, it is necessary to begin work to strengthen the base.

Typically, cracks begin to appear in winter or spring, since it is at this time that an improperly created foundation begins to rise or settle unevenly. It is worth remembering that the foundation can burst due to many reasons, so it is necessary to think about this problem at the stage of designing a house.

Eliminating the problem of cracking of concrete structures

What to do if the concrete cracks after pouring? If cracking begins when the mortar hardens (within no more than two hours), it can be eliminated by additional vibration compaction.

How to eliminate cracking in concrete after pouring:

1. Clean the surface from flaking particles and shrinkage damage. For this, a metal brush and foam glass are used. Through cracks are cleaned and expanded for better filling with mortar.
2. Remove dust and dirt particles with a strong jet of air.
3. Prepare the solution and fill the resulting defects. The composition can be introduced by injection under pressure to compact the mass or by grouting using a sealant.
4. When the repair compound has hardened, the surface is re-brushed with a wire brush.

Materials for work

Cracks in fresh concrete after setting are eliminated by rubbing in a special composition. To do this, use special mixtures for repairing concrete surfaces or a high-quality cement solution (3:1 cement-water ratio, plus a plasticizer or sealant). If cracks in concrete have arisen due to exposure to groundwater, a solution with waterproofing properties is applied. Large cracks in concrete can be additionally reinforced with wire.

We repair the plaster ourselves

The assortment of modern construction stores makes it possible to choose ready-made solutions for repairing a plastered surface without resorting to preparing the mixture yourself. There are products available on the market that are designed to address both major defects such as large ridges, gouges and chips, as well as cracks and other minor defects. Consultants and managers of manufacturing companies and retail outlets will easily select a composition suitable for sealing cracks, based on their nature and your financial capabilities.

So, you have purchased a dry mixture for work, a spatula, and stocked up on a powerful drill with a mixer attachment for mixing solutions. Where to start eliminating defects? Oddly enough, in order to get rid of a crack in the plaster, it needs to be widened and deepened. Therefore, you will have to find a hammer and chisel in your toolbox, and also take care to protect the surrounding area from dust and splinters of material. You don’t need to ignore your own safety - work gloves and safety glasses will protect you from injury.

To begin with, carefully deepen the crack by 1-1.5 cm, making careful and precise blows with a chisel. During the work, it may become clear that cracking is associated with such an unpleasant phenomenon as peeling of the coating from the base, and in this case the scope of work will increase somewhat - all fragments of plaster lagging behind the walls in the area of ​​cracks must be chipped off to the boundaries of the durable coating. As for cracks, their edges should be as perpendicular to the wall surface as possible, and the bottom should reach the base - a brick or concrete surface. When this most labor-intensive stage of work is completed, it is necessary to thoroughly clean the prepared cracks with a wire brush, and then remove dust using an industrial or regular household vacuum cleaner.

The next, no less important step will be priming the surface to increase the adhesion of the material used for sealing to the existing plaster, which probably differs in its physical properties. To do this, use deep penetration primer, applying it with a wide brush so that it completely covers the working area.

While the soil saturates the wall and dries, you can start preparing the solution. You should not experiment with proportions - manufacturers know their work very well and indicate the optimal ratio of water and dry mixture in the instructions for the products. Mixing is done with a drill and mixer at medium speed, making sure that the mixture is homogeneous. Having prepared the mixture, you can safely begin sealing. We take a spatula and slowly begin to fill the cracks with the mixture. For wide and deep defects, metal spatulas 10-20 cm wide are suitable, and narrow rubber spatulas are suitable for working with thin cracks. An important rule: to effectively combat cracks, you must ensure that the volume of the embroidered crack is completely filled, so do not rush and carefully lay the repair mixture, making sure that no voids form in its volume.

After the cracks are completely filled with the mixture, you need to give it time to set. Despite the temptation to apply the finishing touch to the repaired wall at the same time, it is worth waiting at least a day, and if the work is carried out on the facade of a building in wet weather, then 2-3 days.

Why does concrete crack and crumble when it dries?

Private developers, not being professional builders, often do not understand why concrete cracks when drying.

Often, if prepared and poured incorrectly, concrete cracks and crumbles after drying.

It seems that high-quality components for concrete were used, and the proportions were maintained correctly, and the pouring technology was followed, but cracks still appear in the concrete monolith. So why does this happen and are there ways to avoid it?

Dust

In order not to later wonder what to do if the plaster on the walls cracks, you need to remove dust from the surfaces treated with it in advance, and to the maximum. Its presence significantly impairs the adhesion of the liquid solution, as a result of which cracks will certainly appear on the walls or ceiling, albeit not immediately.

It is worth noting that it is not at all necessary to dust all walls and ceilings. It is enough to moisten them a little from a spray bottle, but only before starting finishing work, and not in advance.

Gypsum plaster: subtleties of use

The answer to why gypsum plaster cracks literally immediately after drying sounds different than in the situation with its cement-sand counterpart. In this situation, the primary sources of defects are as follows:

1. Gypsum plaster cracks when drying where the surfaces being treated have not undergone rough preparation. That is, cracks and voids were not removed from them, into which gypsum would then gradually penetrate, causing ruptures in the decorative layer.
2. Excess water is why plaster on walls cracks, because gypsum mixtures are extremely susceptible to large amounts of moisture, which weakens their structure. This is especially true when a slightly dried working solution is diluted with water.
3. Another important indicator is the thickness of the applied layer, which cannot be less than 0.5 cm. Otherwise, the moisture will evaporate very quickly and the coating will inevitably “tear”.

It turns out that cracking of plaster is the result of an irresponsible attitude towards its use and disregard for the recommendations specified by the manufacturers. In general, this is a fairly easy-to-use coating that allows you to make a budget-friendly, high-quality, and most importantly, environmentally friendly base for future decorative coating.

What are the causes of cracks in plaster? How to avoid this? What can be done about existing cracks?

Cracks in plaster can appear for several reasons:

The proportions of the components of the solution were not met, it turned out to be heavy (greasy) or the solution* was simply poorly mixed.

We approached the preparation of the surface for plaster irresponsibly. Before applying the solution, be sure to moisten the walls or ceiling with water. If the surface was dry, it will take a lot of moisture from the solution. If the solution is applied to a concrete wall, then notches are made along it for better adhesion of the plaster solution.

Too thick a layer of solution was applied at once. If the wall is uneven, with large deviations (depressions), then a plaster mesh or shingles are stuffed onto the surface. Level in layers: apply the solution in a layer of ~5 mm, give time for the solution to set, then the next layer. The layer of plaster should be no more than 1.5 cm.

There should be no drafts in the room. As the plaster dries quickly, it becomes cracked.

If the cracks are small, they can be eliminated with putty, emulsion paint, or you can use painter's fiberglass. Larger cracks - first, use a spatula to fill the crack, remove dust, moisten it with water, and fill it with solution.

Also, plaster can crack when using old mortar, when it is partially added to a fresh mortar, so it is recommended either not to add old plaster at all, or to add no more than ten percent.

In addition to the layer, which should not be too thick, it is also necessary to properly care for the plaster, that is, to prevent it from drying out prematurely and very quickly. Therefore, it is so important to prevent drafts in the room where work is being carried out. It is also necessary to moisten the surface of the plaster layer if it dries too quickly, for example under the influence of thermal radiation. You can cover the surface with protective shields, or hang it with a wet cloth.

Often, plaster cracks if the composition is poorly prepared. One common mistake is not thoroughly stirring the mixture when adding water. The plaster can also crack due to the fact that it falls off the surface if the wall has areas that have not been cleaned of old coatings. Often cracks also occur when plaster is applied to wooden surfaces. What is important here is multi-layering, the proportions of water in the solution, and the immobility of the layer until it dries completely.

In all cases, it is necessary to establish the cause, remove the problem area, and reapply the plaster solution. For large layers, a mesh must be used.

It cracked when - then when you are making repairs when it dries out or the plaster is simply cracked in the room, if it is in the room, then the walls are cracking in the house due to temperature differences, you need to cover it up, putty and seal it in short to make repairs. If you are making repairs and applied plaster and it cracks and warps when it dries, it’s because you butted (poured) a lot of water into the solution, or the second option is that it began to harden and you stirred it by adding fresh solution and water, that is, it’s your own fault, but this not a problem, let it crack, when it dries, fill it with finishing putty, and if the cracks are deep, then mix the putty thicker and cover it up - that’s the whole solution to the problem.

According to the rules, small cracks in plaster are a natural phenomenon; moisture leaves the solution. Previously, they used to plaster with cement mortar, and then grout the next day, but not earlier than one day, so microcracks were grouted. Nowadays they use ready-made gypsum-based mixtures.

The cause of cracks on such plasters may be a thick layer. To prevent this from happening again and you need to apply a thick layer at a time, you need to “draw” notches, and repeat tomorrow, leveling it out.

In general, on each bag of the mixture it is written how and what layer to apply; if you follow the recommended instructions, everything will go smoothly.

Glue the reinforced mesh and plaster the top. This applies to large cracks, for example cracks at joints. As for small cracks, there is no need for so much work; it will be enough to use grout.

Problems with the strength of plaster arise quite often at the initial stage of finishing work. Plaster cracks not only on the outer surface; cracks are observed in the most unexpected places. The appearance and development of cracks is expressed at the outer corners of the walls, especially in the lower part adjacent to the base surfaces of the masonry. Less commonly, plaster finishes can crack, peel off in sections, and eventually fall off the wall.

Causes of cracks

Cracks in concrete can appear for a variety of reasons. Conventionally, these reasons can be divided into several large groups:

• structural;
• structural;
• influence of external factors.

Structural cracks arise due to miscalculations by designers or due to the introduction of unjustified changes to the design calculations of the structure, such as replacing the M100 grade mortar with a lower grade when pouring it or erecting an additional floor that was not taken into account in the design.

Such cracks are a serious threat to the load-bearing capacity of the structure, even to the point of its destruction. But to eliminate the causes of their occurrence, you need very little: trust only reputable companies to carry out design calculations and do not deviate from these calculations either during concrete pouring or during further construction.

Cracks in concrete can also appear under the influence of external factors: fire, flood, soil movements due to an earthquake or nearby explosions. The reason for their appearance is practically beyond the control of human will, so their prediction is impossible.

Structural cracks are the most common and most diverse group of cracks in concrete. Often the danger of such cracks is underestimated and sufficient measures are not taken to eliminate them, which leads to the concrete monolith losing its strength characteristics and its gradual destruction.

Causes of the phenomenon

The more layers of plaster, the greater the risk of cracking.
To combat the consequences of cracking, its causes are determined. Identification will show in which direction to carry out repair work in order to ultimately get rid of the negative phenomenon. Many experts know.

The integrity of the applied plaster coating made from a sand-cement mixture can be compromised for a number of objective reasons. The most common are the following:

• presence of pollutants on the rough surface (dust);
• number of layers;
• without preliminary reinforcement;
• uneven mixing of the solution used;
• the initial quality of the plaster mixture used;
• movement of the structure itself (for example, shrinkage).

Often gypsum plaster cracks when there is too much water in the mixture.
In the latter case, the entire building requires repairs. Simple is not enough here.

The reasons for deformation of gypsum plaster differ from those stated above. The sources of problems are:

• the defects in the base (cracks, voids) into which the plaster would eventually fall were not pre-plastered;
• excess water (gypsum is very susceptible to moisture), especially adding it to a dried solution;
• applying a layer less than 0.5 cm thick (causes rapid evaporation of moisture).

The number of layers is important for sand-cement mortars. Application of gypsum and decorative mixtures to a cleaned base is possible in one layer.

Types of structural cracks

Structural cracks in concrete are the most common and diverse group of concrete cracks. These are actually shrinkage cracks. The reason for their appearance is the natural physical and chemical processes occurring in concrete. They are especially active at the initial stage of maturation of the concrete monolith; then their speed slows down, but the processes themselves do not stop until the concrete has completely matured.

Reasons for the formation of concrete cracks.

In other words, these damages appear in the concrete due to the drying and shrinkage of the concrete mixture after pouring. It is well known that a concrete mixture consists of 4 main components: cement (binder), sand and gravel or crushed stone (fillers) and water. Each of the components plays its own strictly defined role in creating a concrete monolith.

Freshly prepared concrete mortar has a plastic or even liquid consistency. The mixture poured into the mold begins to harden. The further this process goes, the more the cement and water contained in the concrete are reduced in volume. As a result, shrinkage of the poured mixture occurs, and in the body of the forming concrete monolith, due to the compaction of the mass, loads arise that the cement mortar, which has not yet gained sufficient strength, holding together the mixed components of concrete, is simply unable to cope.

As a result, shrinkage cracks are most often a consequence of processes occurring inside the hardening concrete monolith. Conventionally, they are divided into:

• damage from plastic shrinkage;
• temperature-shrinkage damage;
• shrinkage damage from drying out the solution.

It is very important to correctly determine the cause of damage in a concrete monolith, because the method of repair directly depends on this.

Criteria for choosing a solution

Regardless of the nature of the defects, you will need a solution to cover them. Sometimes chamotte (fireclay clay) or a traditional mixture of sand and clay is used for this. The modern market of finishing materials offers a large selection of different grouts and adhesives. You can make regular grout yourself. There are several recipes for traditional putties:

• Sandy. To mix the composition, you need 4 parts of river sand, 2-3 parts of lime mortar and 3-4 parts of cement mortar. All components are kneaded until smooth to form a plastic mass.
• Fireclay and clay. This type of putty consists entirely of fireclay or clay. Both materials can be purchased at a specialty store.
• Lime. One of the simplest and most common putty for Russian stoves is lime solution. To do this, buy a liquid mass or extinguish the dry composition.
• Cement. For furnaces, it is optimal to use the M400 composition; 0.5 cement is diluted to 1 part water.

All materials are equally popular in caulking stoves. In order to choose a solution suitable for your stove, you should familiarize yourself with the pros and cons of each of the presented compositions.

Fireclay clay

This type of clay is considered one of the most popular putties among traditional compositions. Fireclay is considered a very reliable material; it is resistant to processing at high temperatures. Most of the ancient stoves, coated with fireclay clay, are still functioning.

You can buy fireclay in almost any construction department. The material is packaged in bags of 5, 10, 20 and 50 kg. Before application, the clay must be diluted with water and left for a day to gain viscosity and plasticity.

Sand coating

This composition is very popular due to its low cost. Moreover, it is used not only for coating, but also for laying seams during laying. The low cost of the components does not in any way affect the quality of the composition. After kneading, you will get a very plastic mass that will gain strength after a couple of heating cycles.

To prepare the sand-clay mass, use the following instructions:

• For 1 part clay, take 3 parts water, mix it all and leave it for three days.
• After 36 hours, the composition is mixed again by pouring water into it. To remove lumps, the mass is passed through a fine sieve (1-2 mm mesh).
• Excess water is drained from the mass, and everything is kneaded again. After which you should get a composition reminiscent of sour cream in consistency.
• The final step is adding sand. At this stage it is very important not to add too much sand. The component is poured into the mass gradually, stirring with a stick. During the kneading process, you need to check the amount of composition sticking to it. The quality of the composition is determined by the abundance of mass on the stick. There should be small lumps left on it, no more than 2-3 cm. The ratio of components in the composition is 1:2.5, where 2.5 is clay, and 1 part is sand.

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The coating composition is thoroughly mixed and checked for plasticity. To do this, roll the mass into a ball and squeeze it between your fingers. The correct composition turns out to be plastic, like plasticine; when pressed and rolled, it wrinkles well and does not crack. If chips form on the ball, you should add a little more water.

Oven grout

Stove grout is considered the optimal composition for beginning craftsmen. The mass is very easy to work with, but most importantly, it has high ductility and durability. Once applied and dried, it can withstand temperatures of 10,000C?.

Note! Before grouting, the walls are moistened in the cracks.

The disadvantages of this composition include its high cost, but it is fully justified by its high characteristics. If you want to save money, you can make the putty yourself. To do this you will need:

• clay 1 part;
• 2 parts water;
• 4 parts sand;
• 1 part finely chopped straw;
• a pack of regular salt.

The clay needs to be mixed with water (1 part water and 3 parts clay), after which the mass is left for a couple of days. Then sand is poured into the solution and gradually mixed. At the very end, the composition is supplemented with straw and salt, and everything is kneaded.

Furnace glue

This composition can also be purchased at a hardware store. It is very easy to mix and apply.

Today, the construction market offers two types of glue: plastic and hard. The first is optimal for restoration (sealing cracks), the second is used as a finishing touch.

Important! Oven glue dries very quickly, so you need to work with it as efficiently as possible. It is recommended to mix the composition in small portions and immediately apply it to the cracks.

Application of the composition is carried out according to the following instructions:

• kneading 1 liter of glue;
• wetting areas with cracks with water;
• treating cracks with a mixture (you need to push the composition as deep as possible);
• mixing 5-6 liters of hard glue;
• finishing of the furnace.

Cracks can form on any structure; this process should not be started. Timely restoration can significantly extend the service life of the furnace.

Previously, classical solutions were used, taking into account combinations of heat resistance, increased heat capacity and thermal expansion equal to the brick material. To make such solutions, fatty clay was used.

Today you can purchase dry mixtures, certain types of clays and other compositions that simplify construction and repair work. It should be noted that not every such composition has the necessary characteristics - fire resistance, heat resistance, gas tightness.

The solution must be heat resistant, withstand high temperatures and exposure to chemically active substances. In addition, the gas density level must be quite high. The seams do not allow flue gases to pass through, but moisture must pass through the finished mixture for the stove to “breathe.”

Damage from plastic shrinkage

Scheme of crack formation due to shrinkage.

This type of damage usually occurs due to intense loss of moisture from the exposed surface of the laid concrete, resulting in uneven shrinkage and compaction of the concrete mass.

This process occurs at the very beginning of setting of the poured concrete mixture. Due to the evaporation of moisture, the surface of the solution actively loses volume, while the middle and bottom layer of laid concrete remain in their original dimensions. The result of this shrinkage is the appearance on the surface of the concrete mixture of a network of small (the width of a human hair) and shallow cracks.

Phenomena similar to those described occur with concrete during precipitation. When it rains, the surface of the concrete gets wet, and a certain amount of moisture gets inside the monolith. When the rain stops and the sun comes out, the wet surface of the concrete heats up, expanding, and cracks may appear on it.

This type of damage also includes cracks that appear in concrete under the influence of gravity. The reason for the appearance of such cracks is insufficient compaction of the concrete being laid. In this case, the following results: the forces of gravity act on the setting concrete monolith, and if insufficiently compacted areas remain in its body, then the mixture in these areas will continue to compact, breaking the integrity of the concrete monolith.

Nuances of testing clay plasticity

Different clays differ in their plasticity. There are:

• “fat” clays with high plasticity;
• material of medium ductility;
• “lean” clays with a low level of plasticity.

I determine the level of plasticity using a simple method. The clay is poured with water to turn it into a dough-like mass suitable for molding. The material is used to make cylinders seven centimeters long and 30 mm in diameter, the ends are pinched with fingers and slowly torn apart. Plasticity is judged by the shapes that the cylinder takes at the point of rupture, by its elongation. A plastic material is characterized by the formation of a long and thin neck, and if the clay is thin, the neck will be thick and short.

The level of plasticity is determined in another way. Flagella about twenty centimeters long and 1.5–2 mm in diameter are rolled out of the working material and bent into semicircles or pretzels. If cracks appear on the materials at this time, the clay is thin. Cracks that form during bending indicate that the clay is of medium plasticity, and fatty clay can be identified by the complete absence of cracks in the samples.

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Temperature-shrinkage damage

Scheme of processes during concrete hardening, formation of structure and formation of properties.

Such deformations occur because the cement used for the binder, in contact with water, enters into a hydration reaction, which results in the release of a large amount of heat and, in accordance with physical laws, an increase in the volume of the solution.

In the mortar being laid, this heating and increase occurs evenly, but in hardening concrete, hydration slows down in hardened areas, and continues with the same force in unhardened areas. This unevenness causes damage to the drying concrete.

The hydration reaction also has the opposite effect, which is no less dangerous for the integrity of the concrete monolith. In the hardening upper layers of the poured concrete mixture, hydration stops and they decrease in volume, while in its deeper layers the process continues and they, accordingly, increase their volume. The result of such exposure to multidirectional forces on the monolith often results in ruptures of the concrete monolith.

Why does concrete crack?

The main reasons for cracking of strip foundations are:

• Processes occurring in the soil associated with its subsidence or heaving.
• Excessive concentration of moisture in the soil, causing it to rise.
• Soil compression associated with the operation of the drainage system.
• Violation of the rules for installing formwork or errors in its calculation.
• Premature application of forces to a concrete mass that has not reached operational strength.
• Errors when choosing the optimal cross-section of steel reinforcement.
• Violation of steel rod placement points.
• The presence of air cavities associated with poor-quality sealing.
• Failure to observe the solution holding time.
• Deep corrosion of the reinforcement located inside the monolith.
• Shrinkage and temperature processes occurring in the initial and final stages of hardening of the solution.
• The reasons are seismic or man-made.

One of the main problems that relate to the structural integrity of the foundation is the appearance of cracks in the foundation. According to statistics, the appearance of cracks is caused by temperature changes (90% climate change), and cracks can also arise due to other reasons. It is about ways to solve the problem that has arisen, as well as cracks of a different nature, that will be discussed in this article. Instructions for installing a pile-strip foundation are here:.

What to do?

What to do if a crack is found in the foundation? If the size of the resulting crack is insignificant, then surgical repair should be abandoned. This does not mean that the matter will be left to chance. It is necessary not to touch it for the reason that it will be necessary to track any changes that will occur to it in the future. Will they happen at all or will everything remain in place? Also, its “naturalness” should indicate the root cause of its occurrence, and this requires a lot of time.

If the owner of the house is in a hurry to seal the crack, then soon it will appear not only on the foundation of the house, but also on its walls. Also, in the future, this may lead to jamming of doors in rooms, deformation of the structure itself and, as a result, destruction.

A number of steps must be taken in order to monitor crack formation.

The first step is to prepare any cracks found. Clean them from various dirt and rinse thoroughly with water. Then a beacon is placed on the cracks. The beacon is a cement or plaster strip 12-20 cm in size. There are thickenings at the ends of the beacon; it is on them that the installation number should be written. The third step is to monitor changes in the nature and structure of the crack.

Acceptable cracks in the foundation are those that do not continue to grow over time, i.e. they form on the outer surface of the foundation.

Causes

Based on the opinions of experts and architects, this kind of problem worsens during the demi-season period (winter-spring). Even the slightest deviation from the norms for laying the foundation in a given period of time can lead to large deformations, because in winter, under the influence of frost heaving forces, uneven lowering and raising of the structure can occur. Read how to do it and what brand of cement is needed for this.

In the spring, due to differences in soil thawing, uneven settlement of the support may occur. Practice shows that a high-quality foundation can withstand this kind of load, but this lasts for a certain period of time.

If there were any violations during the pouring of the foundation, then after twelve months the entire foundation may be dotted with cracks of varying depths.

There are now three main causes of cracks:

• Operational. This type of violation is associated with improper operation of the building: an increase in the level of load on the foundations (for example, the construction of an additional floor), poor drainage in the building area, as well as a high level of humidity in the basement and plinth.
• Structural. These reasons are associated with calculation calculations, namely: with an incorrect calculation of the load produced on the foundation of the building, from the bearing capacity of the soil at the site where the foundation is installed. You can also add here the refusal to conduct a soil analysis, and a number of other design and architectural errors.
• Technological. These types of reasons include violations that occurred during the construction of the foundation: incorrect installation of formwork, incorrect reinforcement of the base, incorrect approach to choosing the brand of building mixture, as well as installation of the foundation of the house above the level of groundwater flow.

Types of foundation cracks

At the moment, all cracks that occur on the foundation are divided into the following types:

Cracks in the foundation of a house

Cracks can occur in the foundation of any structure. It doesn’t matter at all what the structure is made of:

• A crack in the foundation of a wooden house is a rather rare phenomenon, but it still happens. It occurs due to a long period of operation and increased load on the foundation of the building.
• a crack in the foundation of a brick house is common and requires serious action. Cracks in such houses grow quickly, because the brickwork is not a monolithic structure.

Repairing foundation cracks

It would be more correct to talk about repair work and strengthening foundations, which are most often encountered in practice:

• Shallow type strip foundation;
• Pile foundation;
• Concrete type foundation.

At the moment, innovative injection technologies can be used to repair concrete foundations. Such a foundation involves drilling holes at the base, which are then filled with synthetic resins or concrete.

The diameter of such a recess is 0.3 cm, and the required depth can be calculated using the formula: 1/2 x SF (base width). To eliminate the crack, the solution is injected under high pressure.

To seal cracks in a shallow strip-type foundation, it should be deeper. This is accomplished by forming a reinforced concrete structure under the foundation itself, which significantly increases the base area of ​​the structure.

But as for strengthening the pile foundation, it should simply be converted into a strip foundation. The foundation area will increase and the load will decrease. In practice, it is necessary to rely on external factors.

Video

Watch video tips that will help you decide what to do if the foundation cracks:

The appearance of cracks on the surface of a concrete monolith is an alarming signal that cannot be ignored, since disruption of the structure gradually leads to fragmentation of the base or floor slab. No one is immune from mistakes during concreting, but most often concrete cracks due to gross violations of technology and attempts to save money where no standards allow changing the order of work or the component composition of the mixture.

The procedure for preparing and pouring concrete structures is defined by SP 20.13330 - SP 25.13330; it is transferred to the TTK technological maps for any well-organized work, even if we are talking about a private house. But on-site builders do not always follow the rules, and cracks can appear several hours, days and even years after loading concrete into the formwork.

Shrinkage damage from drying concrete

This type of damage usually occurs because a concrete monolith that has already set, but has not yet fully matured, continues to decrease in volume.

This is a feature not only of concrete, but also of any cement and adhesive compositions, such as cement screed, plaster, etc.

This is the most common type of shrinkage damage, and preventing the formation of such cracks is a very difficult task. In addition, such temperature damage widens and deepens small cracks in concrete that appeared from the first two types of shrinkage damage.

Typical Causes of Concrete Cracking

Typical situations, examples and reasons for the destruction of a concrete monolith will be given in this article. A mistake well known to builders when working with concrete is adding water to the solution a few hours after pouring, when the initial setting prevents vibration compaction and the loss of plasticity becomes very noticeable.

With an increase in the water-cement ratio in the solution, the hydration time changes, and the changes occur unevenly, since water does not enter all parts of the formwork equally. After just a few hours, sometimes days, a characteristic crack appears - a shrinkage one, which tends to cut through the entire body of the monolith.

Most likely, this monolith in the photo is no longer suitable for further use. With an opening width of 0.3 mm or more, such a crack will become a gateway for water to penetrate into the concrete, which will lead to an increase in its opening in winter. A detailed study will show that parts of the structure have separated, and the internal reinforcement no longer holds them securely enough.

There is only one recipe here - buy concrete and do not dilute it with water due to the initial setting. It is much more reasonable to carry out vibration laying within the period established by the standards; sometimes it can be repeated, but do not increase the plasticity, violating the ratio of water and cement in the solution.

How to water concrete?

Concrete should be watered with water through a sprayer, sprinkler or watering can, but not with a direct stream. The watering schedule is something like this:

• 2 hours after pouring and in the first 5-7 days of ripening - every 3-4 hours;
• in the next 7 days 2-3 times a day.

In hot and sunny weather, you can water more often as the concrete surface dries. If, when watering, concrete makes a hissing sound, a reaction occurs - this is already a sign that the concrete no longer has enough water and it absorbs it.

Concrete Maintenance Plan

Caring for concrete should begin 2-3 hours after finishing it. If this is possible, then you need to protect the surface of the concrete from direct sunlight: this will avoid heating, and therefore increased evaporation of water. In the case of a strip foundation, this is quite simple to do, but when pouring a monolithic slab, the surface can be very large, and protecting it from the sun is problematic. In addition, the coating will need to be removed periodically to water the concrete. Therefore, when caring for a slab foundation, you can simply water it more often to prevent overheating in the sun.

Causes

In construction theory, there are three main causes of concrete cracking:

1. Constructive failures.
2. Structural changes.
3. Action of external factors.

Constructive failures

The appearance of cracks is associated with errors at the design stage, exceeding the permissible load on the element, or poor-quality components for the manufacture of the concrete mixture. The formation of cracks as a result of design miscalculations does not depend on the filling technology, the quality of care and the qualifications of the working personnel.

Structural changes

Most of the cracks are associated with them. The influence is exerted by internal chemical processes, concrete pouring and maintenance technology.

There are three reasons:

1. Plastic shrinkage. At the beginning of the hardening cycle, the outer surface of the concrete mixture loses moisture faster and decreases in volume than the inner and lower layers. The structure is covered with a network of small, non-through cracks. Destruction occurs in a similar way under rain, as well as gravity.

2. Temperature shrinkage. Destruction of integrity as a result of hydration, a chemical reaction between cement and water. Thermal energy is released. The concrete mixture increases in volume. In the upper layers, hydration occurs faster than in the middle and lower layers. As a result, the concrete “tears” from the inside.

3. Drying. A common cause of deep cracks. The concrete sets, but continues to decrease in volume and cool. Internal stresses rupture the foundation, causing deep cracks to appear.

Action of external factors

Destruction occurs quickly and unpredictably. Heavy rain or snowfall during strengthening, earthquake or shrinkage of the old foundation. All this can cause cracking.

Construction from concrete or reinforced concrete is a responsible undertaking that requires knowledge of the specifics of the work. Not all negative factors that lead to cracking can be eliminated, but it is possible to reduce the risk of destruction.

You can purchase concrete from the manufacturer at reasonable prices from the company.

Cracks in concrete

If small cracks appear after pouring concrete, they must be repaired as quickly as possible to stop the destruction process.

Work process

Regardless of the chosen composition, sealing shrinkage cracks in concrete is carried out almost the same way.

1. If there are chips around the defect, remove the broken concrete pieces immediately.
2. Expand the crack along its entire length with a chisel and hammer, and then deepen it to 5 mm with a spatula. This will help the solution not fall out and reliably fill the entire space.
3. Clean the surface first with a vacuum cleaner, and then with a brush, water and any detergent. Remove any remaining moisture with a sponge.
4. If the cracks in the concrete after pouring are wide enough, make transverse grooves along them and place pieces of wire with a diameter of approximately 4 mm in them. These staples will help the compound stick inside.
5. If reinforcement is visible in the crack, it must not only be cleaned, but also treated with an anti-corrosion compound.
6. Fill the crack with your chosen compound, doing it slowly so that it settles as tightly as possible. Level the surface. Take into account drying shrinkage and make the fill layer slightly above the surface. If it is a sand-cement mortar, lightly moisten it with water after pouring.
7. When the solution has hardened, remove the excess with a spatula. A grinding machine will help achieve a smooth surface.

Purpose of concrete care

To prevent concrete from cracking, it needs care: you need to ensure uniformity of its temperature and humidity throughout its entire volume. The fewer differences there are, the better the foundation will be.

It is also necessary to provide a sufficient amount of water so that all the cement reacts with it and binds the crushed stone and sand. If the concrete has dried evenly but under conditions of lack of water, then some of the cement will remain unused. It is best to pour concrete in the summer, and at high temperatures and under the influence of the sun and wind, the water from the concrete will evaporate. These losses must be replenished by watering the concrete.

When pouring in winter, you need to use warm water, and maintenance becomes very difficult: you need to constantly heat up the concrete, because at low temperatures, maturation slows down, and at negative temperatures it stops completely. It is impossible to create such conditions during independent construction, so this option is not even considered in this article.