Cracking of plaster - 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.

Causes of cracking plaster

We can confidently say that there are not too many reasons why plaster cracks, and they have all been known for a long time. Let's list them. Plaster can crack due to:

• Violations of plastering technology;
• Using an inappropriate or incorrectly mixed mixture;
• Applying too thick a layer of plaster;
• Too much quick drying applied layer of plaster.

Accordingly, each case requires its own solution.

Thus, violations of plastering technology may include the absence of a primer. If you are plastering walls made of porous building materials, such as brick, they must be pre-installed, otherwise they will begin to draw moisture from the plaster, which will lead to cracks.

Primer of walls

The mixture must be mixed in accordance with the proportions. If there is too much cement in it, then all the cement will not be able to react with water, and this will lead to the appearance of numerous cracks and a decrease in the strength of the plaster layer. Excessive amounts of sand can also lead to cracking, but for different reasons.

If you plan to apply the plaster in a thick layer, be sure to use reinforcing materials, and also apply the plaster in several layers. Otherwise, it is almost guaranteed to crack, and it will be impossible to save such a layer of plaster.

Reinforcing mesh for plaster

The plaster should not be allowed to dry too quickly. Moisture should not evaporate, but react with cement - it is due to this that its transformation into monolithic concrete. If it evaporates ahead of time, then instead of concrete we will get a weak and cracking layer. Therefore, observe correct modes temperature and humidity.

What to do if the plaster is cracked?

In most cases, all of the above problems must be dealt with on a large scale, that is, the work must be completely redone, removing a layer of old plaster and laying new one. Covering up cracks is unlikely to help the situation - it will not add strength to the plaster, and new cracks will appear instead of old ones.

However, if there are few cracks and they do not pose a visible danger, then you can try to cover them up without redoing the layer. So, at the stage of setting the solution, the situation can be corrected with cement mortar in the proportion of 3 parts cement to one part water plus a plasticizer. It needs to be carefully rubbed into the cracks and monitor the subsequent development of the situation.

Repairing cracks

If you find cracks in the plaster only after it has completely hardened (at least eight hours must pass from the end of the work), then you can fix them as follows. First of all, it is necessary to clean the cracked areas; for this, a wire brush or any other suitable tool is usually used.

After this, the debris and dirt that has formed on it is carefully removed from the surface. Using a jet of air, fine dust is blown away (you can use a regular vacuum cleaner for this), and then the damaged area is carefully covered with repair material. Such solutions can be purchased at any hardware store. When the solution has hardened, the treated surface is once again treated with a wire brush.

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 most quality work do not guarantee peeling and cracking.

Defects on plastered surfaces appear as a result of flaws in construction, from negative impact atmospheric phenomena, 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 wooden walls The strength of the bottom layer of shingles is checked. On concrete, brick, stone surfaces Defects in the form of chips, large cracks are removed, notches are made and cleaning is carried out 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 mistake is when mixing the finishing solution. It is also possible that drying occurred too quickly or that the solution contained an excess of astringent.

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?

Plaster collapse occurs due to high humidity, if the solution is applied incorrectly to the surface, the mixture is of poor quality. 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 make 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, which 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 apply various ways plastering, 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. Adjacent edges are smeared aqueous solution PVA glue.
4. The area to be repaired is covered with a base layer, then with plaster until full recovery required thickness.
5. Adding texture, coloring.

1. Peeling, cracking of plaster and changes in the geometry of the premises due to the large layer of applied plaster material;

2.Violation temperature regime(at temperatures above 23°C, the surface must be moistened before applying the solution; at temperatures below +5 plastering work cannot be performed, or additionally heat the room with heating devices)

3. Improved and high-quality plaster should be performed along beacons, the thickness of which should be equal to the thickness of the plaster coating without a covering layer;

4. When installing single-layer coatings, their surface should be leveled immediately after applying the solution, in the case of using trowels - after it has set;

5. When installing a multi-layer plaster coating, each layer must be applied after the previous one has set;

6.Each previous layer must be stronger than the next one;

7. Drywall must be glued to the surface of brick walls with compounds corresponding to the design, placed in the form of marks, measuring 80x80 mm. And also on an area of ​​at least 10% along the ceiling, floor, corners of the vertical plane every 120-150 mm, in the spaces between them at a distance of no more than 400 mm, along the vertical edges - in a continuous strip. Sheets to wooden bases should be secured with nails wide hats;

8.Installation of gypsum moldings should be done after the base of gypsum has set and dried. plaster solutions;

9. Allowable thickness of single-layer plaster, mm: when using all types of mortars except gypsum - up to 20, from gypsum mortars - up to 35;

10. Gypsum mortar should not be applied to a concrete surface. Cement and gypsum interact with each other chemical reaction, the plaster swells, gypsum penetrates the surface and destroys it. To avoid this, a 4 mm thick lime mortar is applied to the surface;

11. It is unacceptable for gypsum to come into contact with cement or improved lime mortar. It is completely wrong to plaster over plaster with lime mortar, because... When dried, the first layer shrinks, and the second expands. At the same time, they peel off from each other;

12.Often the interior plaster is damaged during electrical installation work; Before plastering, tubes for laying wires are placed in grooves made in the walls and fixed with plaster, because gypsum quickly sets and gains the necessary strength;

13.During installation heating equipment gypsum is also used to attach heating pipelines to walls or when laying them through ceilings. Serious mistake performed when laying heating pipes into a wall or covering them without casing bushings. After filling the holes, the plaster stays there only until heating starts. Under the influence of temperature, heating pipes change their size, and the plaster, unable to withstand such changes, cracks;

14. Along with cracks from thermal expansion, when fixed with gypsum mortar, pipes begin to rust due to the fact that the gypsum absorbs moisture. This leads to rust stains appearing through the whitewash, and in some cases, to pipe failure. Application casing pipes or bushings prevent the formation of cracks, but the bushings themselves are also often fixed with plaster, which leads to their rusting;

15. After some time, the plaster applied to the surface hardens and becomes durable. Accelerating the drying or hardening of plaster often causes cracks. To dry the plaster, you need not only heat, but also air, because... necessary for setting carbon dioxide. If there is not enough of it, the plaster dries out, but does not harden. If the solution contains cement, the moisture quickly evaporates when dried, so converter drying is not suitable at all. Accelerated drying of plaster is possible only with good air exchange;

16. When remodeling, sometimes they use bricks taken after the demolition of a house. After cleaning, the old brick can be used, but if brick that was used in chimneys (impregnated with soot and tar) gets into the new wall masonry, this causes stains. The defect can only be eliminated by replacing the brick;

17.The surface of a brick wall is moistened before plastering, because hygroscopic brick absorbs water from the solution, which is necessary for setting, and the plaster can crack;

18.Before plastering, dirt and dust must be removed from the surface, because they interfere with the adhesion of the solution;

19.K brick wall The plaster sticks well. The concrete surface is smoother and less moisture-absorbing than brick. By technical standards before plastering, spray onto the concrete surface thin layer liquid cement mortar, giving the surface the desired roughness. If this is not done, the plaster may peel off;

20. Before plastering, metal beams are treated by applying a cement-sand layer along metal mesh;

21.Wooden surfaces are covered with shingles before plastering;

22.When finishing corners on slopes at the junction with window frames And door frames It is important to create expansion joints. Therefore, before starting the finishing process, you need to attach the expansion slats. Otherwise, cracks may form in these places;

23. In no case should galvanized profiles be cut with a grinder, as the protective zinc layer that protects against corrosion may be destroyed;

24.In the case when external corner located in walkable places, then installation of a metal corner profile is required;

25.If painting work are carried out at temperatures below +10°, then it is better to add Portland cement to the plaster composition.

The beauty of any building, both inside and outside, largely depends on the perception of the walls. These surfaces occupy 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.

Restoration technology for façade and interior plasters

Repair of residential and commercial buildings cannot be carried out without external and interior decoration. For these purposes, rough, finishing facade, or decorative plaster is used. But no matter how well the repair is done, it is impossible to 100% exclude the appearance of cracks or peeling in the future. They may appear due to improper construction or operation of the building, or atmospheric phenomena.

What to do if the decoration on the walls has come off, peeled off, crumbled, or cracks have appeared on it? Let's consider the main defects and the technology for eliminating them by repairing the plaster walls in individual places.

Blistering, peeling of coating

There are three reasons for this phenomenon:

• the solution was applied to a dry wall;
• the first layer of plaster was of low strength;
• the solution is prepared incorrectly - if the lime mass contains unslaked particles, this can cause the formation of tubercles on the walls.

Remember: Before starting repairs, you need to tap the entire wall with a hammer - a durable coating makes a dull sound, while a peeling coating makes a ringing sound.

Repair of swollen areas is carried out after complete removal of the loose finish. The plaster is beaten with an axe, chisel and hammer. On wooden coverings check the strength of the filled shingles. On brick, concrete, stone walls make notches (or clean the surface with metal brushes). After this, the surface is primed and a new composition is applied.

Replacing a swollen coating with a fresh, high-quality mortar mixture - repairing monolithic plaster

The plaster is cracked, what to do in this case?

Cracks occur if finishing solution was not mixed well enough, had too much greasy composition (too much binder), and dried out quickly. If small cracks appear on the surface, the damaged area is rubbed with gypsum compound or mortar during the repair process.

Note: You can avoid the appearance of cracks in the coating during operation by observing the proportions when preparing the plaster mixture, as well as by thoroughly kneading it before use.

During repairs, deep cracks should be opened, cleaned, moistened, and then sealed with plaster.

What to do if the finish is crumbling

Plaster collapses occur for several reasons:

• due to the use of low-quality solution;
• due to a violation of the technology for applying the mixture to the walls;
• due to high humidity in the room.

If the finish is falling off due to exposure to moisture, before repairing it is necessary to eliminate the cause of the leakage or poor ventilation of the room. Damaged plaster is removed and the wall is dried. After drying, the surface is cleaned, treated with an antifungal compound, and a new finish is applied.

The reinforcing mesh will additionally strengthen the finishing on the wall - repairing crumbling finishing

Technology for repairing decorative plaster walls

Most often, the interior decoration is not smooth, but textured (Venetian, silk, marmorine). Therefore, plaster repair interior walls When buildings peel off or cracks appear, it will take time and effort. The sequence of restoration of Venetian decoration:

• treating the damaged area and the edges of adjacent areas with PVA glue diluted with water in a ratio of 1:5;
• applying base and then finishing layers of plaster;
• giving the coating texture;
• painting the dried area.

Note: The façade plaster is repaired in a similar sequence. The technology for applying the decorative layer may differ (bark beetle, lamb, crocodile).

An example of how to restore a coating damaged by cracks - Venetian plaster repair, photo

Why cracks appear on the plaster after drying, and how to avoid it

The main reasons for the formation of cracks on the finished surface:

• non-compliance technological process applying the solution - the mixture should be applied in layers, the first layers should be the strongest. Cement plaster cracks in the absence of a base - the top layers, drying out, settle and harden in this state on the primer, forming cracks;
• low quality of the applied solution. The cement must be of high quality, and its share in the mixture should not exceed 1/3;
• improper mixing - if there are lumps of dry sand or cement in the solution, cavities and cracks will form in the finish;
• small coating thickness - less than 5 mm;
• another reason why plaster cracks when drying is the lack of reinforcement construction mesh(movable bases);
• improper surface preparation - if you do not clean the surface before applying the composition, do not repair cracks and chips, the solution will not adhere well and over time, small cracks will appear on the ceiling and walls;
• excess water - common reason why gypsum plaster cracks when it dries. A large volume of moisture weakens the structure of gypsum mixtures.

Thus, the main reason why plaster on walls cracks is neglect of the recommendations for the use of the material specified by the manufacturer, as well as the lack of experience in performing repairs (applying finishing).

Despite the abundance of modern finishing materials, appeared for recent years on the market, plastering exterior and interior walls is still one of the most popular ways to protect building structures from external influences and make them attractive appearance. For application to walls and ceilings, mixtures of a wide variety of composition and properties are used, ranging from durable and moisture- and impact-resistant cement-sand mortars to gypsum plasters, practical and aesthetic.

Unfortunately, even the highest quality coating deteriorates over time and may begin to develop cracks. The reasons for this phenomenon can be different - violation of the work technology, errors in preparing the solution, exposure to moisture, shrinkage of the building. Of course, if we are talking about deformations caused by displacement of structures, first of all you should think about solving this serious problem and contact specialists who will help prevent further subsidence of the foundation. But if the appearance of cracks is not associated with emergency, you can completely get rid of them yourself, without resorting to outside help.

We repair the plaster ourselves

Assortment of modern construction stores gives you the opportunity to choose ready-made solutions for repairing a plastered surface without resorting to preparing the mixture yourself. There are products on the market that are designed to both repair serious defects such as large protrusions, depressions and chips, as well as to combat 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 crack area 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.

Next, no less important stage there will be a primer on 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. Important rule: to effectively combat cracks, you must ensure that the volume of the embroidered crack is completely filled, so take your time and lay it carefully repair mixture, making sure that no voids are formed 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 finishing on a repaired wall, you should wait at least a day, and if the work is carried out on the facade of a building in wet weather, then 2-3 days.

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 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.

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