Repairing cracks in concrete: what and how to repair them indoors and outdoors?

Finding a crack in a wall is an unpleasant discovery, whether it is a private home or an apartment building. In this case, it is necessary to figure out why this happened, and then begin to repair the flaws. Modern tools help solve the problem. How to repair a crack in an apartment wall and who should do it will be discussed further.

Cracks in the external and interior walls of the apartment - who should repair it, where to go

Before sealing a gap in the wall, they find out where it came from. There are several factors influencing this process. When it comes to a brick house, this is often associated with its shrinkage. Another reason could be a violation of construction rules. The foundation of a brick house must stand for one winter, and only then further work can be carried out.

The appearance of defects, for whatever reason they arise, requires solving them. And here another question arises - who to contact in order to understand who will do the repairs.

The first authority is the management company. However, in practice, she does not always undertake to eliminate cracks. Then you should go to a design and construction company, which will assess the incident and tell you what to do next.

Before sealing a gap in the wall, they find out where it came from.

Why do cracks appear in walls and what are they?

Gaps appear due to various factors. Before you start covering up wall defects, you need to assess the scale. The presence of a millimeter crack is not scary. The root of the problem may be changes in the soil under the structure, as well as poor stability of the load-bearing walls. You can simply cover it with some object.

However, the scale of the problem may be greater, depending on the material from which the house is built. For brick and concrete, such a small crack is not tragic, but for a foam block it is more significant. Repairing a panel house is easier.

Frequent vibration, windy weather, heavy traffic, high temperatures are phenomena that significantly affect the possibility of defects forming in the walls of different types of houses. Important factors are swelling and shrinkage periods - the reaction of the material to different weather conditions. The purpose of the building and the loads to which it is subjected also influence.

Important factors are swelling and shrinkage periods - the reaction of the material to different weather conditions.

What are the dangers of cracks in the wall of a house?

Before you cover up cracks in a wall, you should figure out how dangerous it is. It’s bad if this is a consequence of violation of construction standards or major repairs.

To check, you can set a mark with a plaster solution; instead, you can use a control strip. To do this, special plaster is applied to the gap, the width is approximately the size of your palm. I wait about a month, if the gap does not appear again, then there is no need to be afraid.

If it appears, they wait another two months; professionals talk about the possibility of waiting three. If the size increases, then you need to contact a professional. He will help determine the scale of destruction and find the right solution.

You can use beacons instead of a tag. With their help, you can check both vertical and horizontal defects.

To check, you can set a mark with a plaster solution; instead, you can use a control strip.

Causes of cracks in walls

In apartment buildings there are frequent problems with the quality of walls. Breaks and cracks appear in the ceiling and walls.

Please note! This may happen for the following reasons:

the building was initially poorly constructed;
the soil has settled incorrectly;
excessive load on the foundation of the house;
frequent flooding with water from neighbors, leaking roofs;
soil characteristics have changed since the building was built;
the wall is drying out;
this reason affects old houses. Sudden changes in temperature can also negatively affect the condition of the house;
severe frosts, freezing of buildings, poor-quality heating.

Small cracks in the walls cannot be ignored. It's much easier and cheaper to fix while they're small. When they increase, it will be more difficult to eliminate existing problems.

Watch the video. Cracks in the walls:

What to do with a through crack in a brick wall

When flaws are found in a room of a brick house, this leads to many problems, the wallpaper begins to fall off, and the entire structure may be at risk. The size of the flaw may vary. And the solution is also different.

When there is a through gap, its sealing begins with cleaning this area of excess elements. The inner part is filled with polyurethane foam, when it dries, the excess parts are cut off. If required, metal brackets are installed inside and outside. The ends of the brackets are bent to the wall and fixed with bolts. The fastener must not protrude above the surface, so the old finish should be removed.

You can replace the polyurethane foam with a solution of cement and crushed stone.

If the flaw is large, more than 10mm, then it is dangerous. Repairs will require the installation of steel rods; they are installed on both sides. They get a reliable frame structure that can cope with stopping destruction.

When there is a through gap, its sealing begins with cleaning this area of excess elements.

Repairing cracks in a concrete wall

The demand for monolithic construction has led to the popularization of concrete houses. And accordingly, the question of how to repair concrete buildings, be it a garage or a house, has become relevant. For the process it will be necessary to prepare a special grinding. To do this proceed as follows:

Cement and sand are sifted to leave only the smallest particles. They will help you get a smooth and durable putty. Then a liquid solution is prepared.
A grater is prepared and a piece of fur is put on it.
Fill the bucket with water; it must be clean.
The grater is soaked, then the solution is scooped onto it with a spatula. Using a tool pressed against the wall, rub the product into the crack, move in a circle, the grater must be constantly wetted.

Such a product can be used not only to eliminate one crack, it can also be used to seal all uneven surfaces.

A durable product is considered to be epoxy resin mixed with a hardener, supplemented with the use of reinforcing mesh or tape.

Such a product can be used not only to eliminate one crack, it can also be used to seal all uneven surfaces.

Methods for fixing cracks and strengthening walls

A common mistake is to strengthen load-bearing structures exclusively with metal reinforced mesh.

It is important to understand that the formation of wide vertical splits (from 10 mm) in itself is a sign of destruction of the wall; repairing such a crack with mortar without a reliable metal screed is not enough. Recommended strengthening options include:

Driving T-shaped metal anchors into dowels located along the edges of the crack.
Placement of longitudinal steel brackets with bent corners into pre-drilled holes in the walls, followed by coating with cement. This method is considered optimal when repairing through cracks from the outside.
Strengthening brickwork from the inside with special interlocking connections.

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When fastenings enter the wall, their depth should be at least half of the total thickness. A combination of fixing elements is allowed and encouraged. Ideally, sealing cracks in brick walls is carried out after installing at least three reinforcing structures: at the top, bottom and in the center.

The use of reinforcing mesh is advisable if you want to strengthen the entire wall area. Such cases include preparation before plastering the facade (even a properly calculated foundation does not eliminate the risk of shrinkage) and strengthening of old masonry. When choosing a method and material for filling cracks, the future exterior finish must be taken into account. All metal elements are treated with anti-corrosion compounds and hidden under plaster or painted.

What is the best way to repair defects in brickwork?

The composition for filling cracks depends on its location: outside or inside the house. The internal ones can be sealed with a gypsum-based solution or a limestone-cement mixture; for non-critical defects, this method is no different from ordinary cosmetic repairs. For external work, it is better to choose more moisture-resistant materials, otherwise the effect of eliminating a crack on the wall of the house will not last long. Recommended options include:

For thin, shallow cracks with a width of no more than 5 mm - seal with pure cement mortar after preliminary clearing and thorough wetting. A special case is microscopic shrinkage formations up to 1 mm; it is better to seal them with epoxy resin.
For cracks from 5 to 10 mm - cover with a cement-sand mixture for repair in a ratio of 1:2 or 1:3 (water is added to the state of a plastic mass - a little more than ½ of the binder).
For wide and deep cracks in brick walls and structures with an air gap, polyurethane foam is well suited. This material requires mandatory protection from ultraviolet radiation, so after hardening is complete, all excess is cut off (not flush with the wall, but 2-3 mm deeper) and covered with the same mortar or plaster.
For cracks of any type - a polymer-cement composition of Portland cement M400, sifted fine-grained sand, PVA and water. In this case, a lot of glue is added - from 1 liter per bucket, this component is added last.
For internal and external cracks in brickwork - use silicone sealants. The advantages of this option include the elasticity and durability of the material, resistance to temperature changes and moisture, and the convenience of filling cracks using a construction gun. The disadvantages are high cost; it is not suitable for volumetric cracks.
If it is necessary to repair the outside of an area with old masonry mortar, mixtures with a slight addition of brick chips are used.

Regardless of the chosen composition, work on its application is carried out after clearing the cracks, tightening with metal (if necessary), removing debris and priming. Upon completion of the repair, the condition of the walls in the brick house is closely monitored for at least 2 months.

Repairing cracks in drywall sheets

Before covering up the cracks in the apartment wall, which are made of gypsum plasterboard, the size of the defect is analyzed. Using a narrow spatula, remove the paint until the serpyanka mesh is visible; if it is not deformed, then the cause of the gap is a poor putty mixture, or the order of the layers is disturbed.

Repair defects as follows:

The crack widens at the edges; a spatula, chisel and knife are suitable for this purpose; the expansion should be approximately 2-3 cm.
This area is sanded to remove the putty layer. Next, sand the edges to remove traces of paint.
Clean the area and carry out priming.
Apply putty to obtain a smooth finish.
The primer is applied again and the dried surface is painted, usually white.

Apply putty to obtain a smooth finish.

Sealing through cracks and defects in drywall

Drywall is often used to create partitions. Including on the balcony. Sometimes the cracks are deep. The repair process will be slightly different:

Remove the damaged mesh.
If there is no serpyanka at all, then the space for a new tape is expanded along its width, and the putty layer is removed.
The joint parts of the sheets must have a cut angle of 25 degrees. Or it is cut off during repairs.
The wall is cleaned and primed.
They install the serpyanka and apply putty.
The primer solution is again applied to this area, then the technology described above for working with small flaws is followed.

Drywall is often used to create partitions.

Armature

Reinforcement is a collection of interconnected particles and elements, which, together with a material such as concrete, in reinforced concrete structures are perceived as beams that stretch the tension. Reinforcement is also used to enhance the durability of concrete in columns.

Reinforcement elements are divided into rigid (angles, channels, rolled I-beams) and flexible (rods of periodic and smooth profiles, as well as knitted or welded frames and meshes).

Let's consider the classification of types of reinforcement.

Depending on the purpose, the reinforcement can be: – working (the cross-section is assigned by calculation, the forces are perceived in the particles of the main load); – structural (distribution fittings that absorb shrinkage/expansion, exposure temperature); – installation (installed to combine the structural and working parts); – anchor (embedded parts).

Depending on the orientation in the structure: – transverse reinforcement, which actively prevents the formation of cracks from emerging stresses near the supports and connects concrete from the compressed zone to the tensile zone with reinforcement; – longitudinal reinforcement that completely absorbs tensile stresses and prevents the formation of cracks in the stretched zones of the structure.

Depending on the conditions of use, the reinforcement can be: – non-tensioned; - tense.

In prestressed pre-stressed concrete structures, the prestressed reinforcement is exclusively working.

There are five possible options for contact between reinforcement and concrete: – contact with concrete structures by friction; – connection on shear bonds; – adhesion (the process of joining when concreting a steel reinforcing element); – interaction of cement mortar and steel reinforcement at the electrochemical level; – compression of reinforcement using concrete after its shrinkage.

If it happens that a crack appears in a load-bearing wall or foundation, this is not a death sentence, it’s just time to take “global” (radical) measures to strengthen the entire structure. We will talk about the simplest and most popular methods of preserving the integrity of a building in this article.

Note.

The article uses conventional terminology.

When purchasing a ready-made house, the new owner in all cases is dealing with a pig in a poke

And it doesn’t matter whether it’s a new building or a renovated old one. Builders erect and repair cottages and private houses in a fantastically short time, which always affects their sustainability and durability

Regardless of the reasons for its appearance, a crack is a frequent and faithful companion of stone buildings and structures. We will talk about the most difficult cases of these unpleasant and dangerous defects - structural cracks, which serve as signals about the appearance of mobility of load-bearing elements. To stop the development of a crack, you should stop the movement and fix the elements, and then repair and “mask”.

Note.

A crack in the trim does not always mean there are defects in the wall material. You should make sure that it is the supporting material that is damaged by removing part of the finish and exposing the defective area for observation.

Let's leave the theory and consider the three most common cases of the appearance of mobility of elements: collapse, blockage and separation of the extension.

What is the best way to cover up cracks in a load-bearing block wall?

Sealing cracks in interior block walls includes 2 methods of work. The reason for the presence of defects is often the lack of reinforcement. The first method is done like this:

The gap is cleaned and widened if necessary.
For strengthening, anchors in the shape of the letter E are used, secured with dowels.
Introduce pieces of broken cinder block into the plaster solution, make them small, then apply the product to the crack.

Second option:

The flaw is expanding.
Primed.
Sealed with mortar.

The reason for the presence of defects is often the lack of reinforcement.

What to follow when repairing cracks, the main rules

Repair activities can begin once a crack area map and defect sheet has been created. They confirm the result of the test and the factors that influenced their appearance. When choosing a method of action, we are guided by the following criteria:

What is the wall made of?
Number of cracks;
Their width;
Branching of cracks.

Repair activities can begin once a crack area map and defect sheet has been created.

How to properly repair cracks

Carrying out proper repairs is the key to obtaining a reliable result. It is important to begin work after the problem has been assessed by experts. They will tell you what is best to use when sealing.

Sealants, water-based compounds, polyurethane foam, and various solutions can be used. The choice is made based on the type of base (aerated concrete, concrete, brick, plasterboard or other), and the scale of the problem. They act in stages, monitoring the quality of work.

They act in stages, monitoring the quality of work.

What mistakes do beginners most often make when repairing cracks in an apartment?

When repairs are done by yourself, it is easy to make a mistake. Usually, beginners incorrectly assess the level of the problem. Or they choose the wrong material to fill the gap. It is also popular to neglect the stage of cleaning the surface from contamination. To prevent them, it is recommended to consult with a specialist in advance and perform each step carefully.

Usually, beginners incorrectly assess the level of the problem.

A crack in the wall may appear unexpectedly; it is important to understand the cause and fix the problem in a timely manner. You can cover up the defect yourself, but advice from a professional will not hurt. The putty agent is selected based on the wall material.

What causes cracks in the walls of a panel house?

If the walls were built in compliance with the technology and the operating rules were not violated, then the possible reasons for the formation of cracks are the following:

Depreciation is the wear and tear of material. End of service life. For example, concrete will last 80-150 years.
Erosion, weathering. Much faster, the natural environment leads to weakening and is a catalyst.
The action of the soil itself and groundwater. Quite a common reason. In addition, foundations washed away by groundwater and cyclic freezing of the soil pose a danger.
Humidity and temperature fluctuations are the most negative factor. Freeze-thaw cycles widen the crack even when the walls are quite resistant to this process.

If technologies were not taken into account responsibly enough, and violations of operating rules occur, then the reasons may be hidden in the following:

Existence of extensions or superstructures. Certain compressive stresses are generated, as a result of which the foundation cushion settles in the soil. Moreover, adjacent cracks may contain inclined cracking in the “downward” direction, and with an opening in the “upward” direction. This also occurs when the superstructure passes along the entire length of the building.
Fluctuating pressure on the foundation along the length of the building. This is often affected by large lengths of glazed areas. This affects the uneven settlement of the foundation.
Construction of a pit near an already constructed structure. Soil displacements cause shifting loads, and accordingly oblique cracks appear, it’s simple.
Interaction between adjacent foundations. With this type of impact, the loads add up and increase the overall point compression of the soil. If one of the buildings was built earlier, then the slope goes in its direction.
Impact of loads on surfaces. This is the storage on the ground near walls of various materials, industrial raw materials and any other products. The result is that the soil contracts, the foundation settles, and cracks are created.
Dynamic influences. This includes moving vehicles, driving piles, the operation of compressors and boilers in various workshops, and any similar vibrations. Also, under the influence of such loads, settlement of the foundation occurs.
Freezing and freezing of soils. Freezing causes foundations to heave. This is especially dangerous during construction, when the walls have low bending rigidity. An extremely negative point is that the walls on which the remaining floors are erected are already being built with these deviations present.
Changes in shape during shrinkage. During shrinkage, breaks often occur in the corners of wall openings in buildings and acquire a radial direction. Such clefts are simply not aesthetically pleasing. On plastered surfaces, small, closed, multidirectional or oriented cracks sometimes form that do not reach the corners. Their reason is the drying of a solution with high fat content.
Wall overload. It threatens to destroy the walls and is accompanied by cracking of the main structures. Cracks of this kind are the initial sign of wall destruction and are extremely dangerous.

In a good way, in order to understand the reasons for the occurrence, you need documentation of the design history, engineering geology, operation of the structure, the location of underground communications and a work project with an author's supervision log.

Danger of a crack in the wall, identification of risks?

Having determined the causes of cracking, you can roughly determine the degree of danger of their presence in the wall. For an objective assessment, you will have to examine the cracks from your neighbors’ apartments and carefully look to see if there have been any redevelopments there. If the relationship is good, the neighbors will show you without any problems, otherwise you will have to collect a commission.

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For the most part, the cracks described are harmless. In new buildings, during the first 5 years, while the house “settles”, this is a fairly normal phenomenon, natural shrinkage.

The degree of danger of cracks in the wall

But perestroika or major reconstruction is already dangerous. The degree of danger is usually determined as follows: climbers place plaster notes or strips of special paper. And within 3-4 weeks they monitor whether cracking will appear on the gypsum mark. When a crack appears, you need to observe for another 8-12 weeks. And if it really grows, you definitely need to contact an expert in the construction field.

Since in this case it is possible to intervene and strengthen the existing foundation of the building. Construction of additional reinforcing structures - trenches along the foundation with reinforcement and filling. Moreover, the reinforcement must be connected to the existing foundation. Holes are drilled in the foundation, pieces of reinforcement are driven in, and on the other side they are welded to the laid rods. These types of work can only be performed by experienced specialists. But we will not consider this extreme point, but will consider how to generally cope with the most dangerous cracks on our own.