Fundamentals of plaster repair of interior walls and facades. Walls with your own hands. Repair of plaster A plastered wall has peeled off how to repair

Plaster is one of the most popular facing coverings. However, if the technological process was grossly violated or negligence was allowed in operation, damage of a different nature occurs: cracks, shedding, peeling.

From this article, the reader will learn why plaster cracks when it dries, the causes of defects and methods for their elimination. As well as the sequence of repair processes for the plastered surface of the walls, both inside the building and the facade.

Technological causes of defects

Violation of proportions in the preparation of the solution or the technology of its application, as well as errors in the preparation of the base, lead to the following defects.

During local repair of wall plaster, in some places, cracks and potholes are cleaned of crumbling particles with a stiff brush, then the exposed surface is abundantly smeared with a deep penetration primer. The time for complete drying is indicated on the packaging and it may vary from manufacturer to manufacturer, although it rarely exceeds 3-5 hours.

Jointing a crack before repair

The covering layer applied to the cracks is rubbed gently, flush with the general level, it is advisable not to allow the solution to be smeared over the previously treated surface.

Fresh plaster with small cracks, scattered at a slight distance from each other, is frayed over the entire area. To repair monolithic plaster, a cement or lime-cement mixture is diluted. As a filler, fine sand with a grain size of 0.3-1.2 mm is used.

Cleaning, dedusting cracks

Repair of plaster of internal walls by grinding the surface:

1. The surface is wetted with water;
2. A little repair mixture is collected on a grater;
3. Apply to the surface of the crack with separate strokes;
4. The grater is cleaned, moistened with water, the working area is sprayed with a brush;
5. The solution is distributed in a thin layer along the crack with circular movements of the grater.

Drying cracks

There is another reason why gypsum plaster cracks when it dries. It's a matter of temperature and humidity. According to SNiP 3.04.01-87, as well as the German standard DIN V 18550:2005-04 for insulating and finishing coatings, the most popular Knauf gypsum plasters must dry at a temperature not exceeding 18-20 ° C, and humidity: walls up to 8 % and air 40-55%. At the same time, it is very important not to arrange intensive ventilation in the room.

Surface cracked as a result of drying out from overheating

For cement compositions, the drying rate at optimal environmental conditions is different, and it also strongly depends on the type of base. There can be much more options for why plaster on the walls is cracking.

Sand-cement and heavy decorative plaster on a brick and concrete base must dry at a temperature of 15-25 ° C and a relative humidity of not more than 75% to avoid cracking. At the same time, the duration of drying depends on the humidity of the wall 5-15%, up to a quarter of the entire period. Therefore, a 2 cm layer can dry from 18 to 30 hours.

Local repair of defects

Grouting a crack with a repair compound

Repair of old plaster is carried out in several stages:

1. Checking the surrounding layer, removing the lagging part;
2. Cleaning and expansion of cracks;
3. Primer;
4. An intermediate layer of repair compound is applied to the crack 2-3 mm below the total wall surface;
5. Until the mixture has hardened, a mesh is applied to its surface with a spatula to improve the adhesion of the decorative layer;
6. After the repair mixture has dried, a decorative, finishing layer is applied, which is given the appropriate texture.

This sequence of actions is suitable for repairing decorative plaster with a uniform pattern.

Plaster is a versatile wall covering. It can be both an exquisite and decorative part of the interior, as well as an ordinary plain background or a draft version of surface preparation for any finishing material. The plaster is quite resistant to moisture and perfectly tolerates various adverse effects, from temperature extremes to scratches from animal claws. However, even this fairly durable material is prone to destruction. You will learn how to correctly repair the plaster of internal walls in this article.

There are many reasons why plaster collapses and loses its aesthetic and functional properties. Most of them are easy to prevent during plastering work, but some cases cannot be foreseen.

Reasons to avoid:

• poor-quality preparation of the base for applying plaster;
• unremoved remnants of the previous coating;
• incorrect selection of mortar for the internal or external surface.

Reasons that cannot be influenced:

1. Cracks that appeared in places of increased load on the surface:

• window frames;
• doorways.

2. Defects in the plaster due to long-term use.

3. Destruction of plaster due to natural disasters, such as earthquakes.

Important! Plaster, like any other material, loses its properties over time, however, any cracks and defects can be repaired with your own hands. The price of plastering internal walls in this case will be significantly lower than when these works are performed by professional builders. We note one more fact that the internal plastering of aerated concrete walls is as easy as finishing brick or monolithic concrete bases. Therefore, the main rule is to follow the sequence of actions and all the conditions of the damage repair technology.

How to check the strength of the coating?

Be sure to check the entire plastered surface before starting to repair a visible damage zone. The check is done in order to prevent the imminent destruction of new sites. To do this, it is easy enough to tap it with a rubber or wooden mallet.

Important! A durable coating makes a ringing sound, and a non-durable one gives a dull tone.

What to choose a solution for repairing damage?

It is mandatory to repair the plaster with the same mortar that the plaster was originally made with.

Important! Do not make a typical mistake by acquiring and making a composition that is more durable, in your opinion, which is not always combined with the previous coating. The price of plastering internal walls in this case depends entirely on the quality of the initial mixture for the mortar, so give preference to trusted manufacturers, but with an affordable cost of materials.

The texture, color and aesthetic appearance of the surface directly depends on which mixture you will use.

Important! If the destruction is significant and caused precisely by the fact that the mortar was initially of inadequate quality, in this case it is advisable to completely replace the plaster, and not to reinforce individual fragments of the wall with a different composition. Otherwise, repair work on the plaster of the internal walls will have to be carried out regularly.

How to properly prepare the walls when repairing plaster?

To save time and money, many prefer to repair only noticeable irregularities and damage, not paying attention to the fact that in other places the plaster can also be kept on parole. It looks presentable, but in practice it is fraught with constant re-restoration of the surface.

To avoid this result, before starting minor repairs, do the following:

Interior wall plaster repair technology

Regardless of the type of material in need of repair, the technology of work is the same:

Video

View the proposed example of a video of plastering interior walls to clearly see the whole process and organize yourself correctly when carrying out repair work.

Features of repairing gypsum plaster

Repair of gypsum plaster is carried out in accordance with the basic rules for sealing cracks on the surface, but there are some distinctive nuances. After checking the wall on which cracks are found, proceed to repair the damage by following the suggested method below.

Tools

For do-it-yourself repairs, you will need the following tools:

Surface preparation

This procedure is not much different from the standard preparation process:

Repair technology

Features of repairing cement-sand plaster

This type of plaster is no more complicated than gypsum, the general algorithm for their implementation is very similar, but the method of applying the mixture and preparing the base also includes distinctive features.

Tools

For this type of wall repair, the following materials and tools are needed:

Technology

To obtain a high-quality plaster coating from a cement-sand mortar, do the work as follows:

Conclusion

When repairing plaster, it is important to be extremely careful and organized. Compliance with all the rules will ensure high-quality and long service life of the new surface. In the case when the surface of your home is significantly destroyed, do not be too lazy to completely replace the plaster, because it is better to do it well once than to redo the work in parts over and over again.

But due to certain factors, such as dampness or an initially incorrect composition, it can fall off in places, crumble, crack, swell, move away from the surface.

In this case, the removal of old plaster is simply necessary.

Depending on the lesion, the removal of plaster can be:

• partial
• complete

To determine the strength of the old plaster and how well it adheres to the walls, you need to examine the entire area and then decide on its complete and partial replacement.

If cement or lime plaster begins to crumble along with the removal of paint from it, then it is impossible to “cure” it, in which case it must be completely removed.

The strength test is carried out with a scraper or spatula. If the plaster crumbles only in individual places, then you can cover it with a solution on fine-grained sand or putty weak areas, having previously cleaned them with sandpaper and primed them.

To determine how strong the plaster of slopes, walls or ceilings is, you need to tap the entire surface with a wooden mallet, hammer or spatula handle.

In places where the plaster is weak, a void has formed under it, so a dull sound will be heard. In these places, the old plaster must be removed.

Tapping the wall with a hammer

If dampness has appeared in certain places (from below, from above) and weakened the plaster, then the removal of the old plaster must be carried out not only in these places, but also by 50 cm more than the level of moisture.

Cracks in old, but durable plaster are sealed with cement mortar and carefully rubbed. In this case, the cracks are pre-expanded to a V-shape and moistened with water.

The solution is applied in several stages: first to the very bottom of the recess, then after drying by 2/3, and only then they begin to completely seal the crack.

If there are grease stains on the old plaster, washing the surface alone will not be enough. It is necessary to prepare the walls for plastering as follows - cut down the oiled places, after which they are repaired with a new layer of plaster.

Removal of old plaster can be done in different ways, the tool depends on how firmly it adheres to the base.

Tools for removing old plaster:

• putty knife
• scraper
• axe
• hammer
• scapula
• perforator
• Bulgarian
• plaster remover

Precautionary measures

1. Use a respirator or gauze bandage to prevent dust from entering the lungs;
2. Wear safety goggles and gloves;
3. Before starting work, determine the location of the electrical wiring, if necessary, turn off the power supply.

Methods for removing old plaster

First, you can use a hammer and tap the entire work surface with a sharp protrusion of the head. Weak patches of plaster will immediately crack and fall off. Then clean the walls with a scraper or spatula.

Durable areas should be moistened with water using a rag or brush; abundantly moistened plaster falls off more easily from hammer blows.

Coarse-grained crumbling plaster can be gradually cleaned with a spatula layer by layer, but this process is very long and tedious. In addition, it requires a lot of strength and frequent change or sharpening of the spatula.

For these purposes, a special mesh is also used for cleaning uneven surfaces, which is mounted on a holder or a special grater.

Surface cleaning device

Advice! To reduce the amount of dust, spray the walls periodically with water using a water sprayer.

When it is difficult to knock down old plaster with manual methods, you can use a perforator with a “blow” function.

How to remove plaster with a perforator? To do this, fix one of the special nozzles in the tool socket, for example, a lance or a chisel, and by switching the switch to the “hit” position, get to work.

Well, if you have the opportunity to remove the plaster grinder. Having fixed a cutting wheel with a diamond edge on it, make longitudinal and transverse cuts on the surface, and then use hand tools such as a spatula, scraper.

When repairing, the question often arises of how to remove plaster from the ceiling around heating risers or between floor slabs.

As a rule, in old apartments these places are plastered very sloppily, there are bumps or depressions on the ceiling. To level the ceiling, it is necessary to knock down irregularities with a hatchet and grind off with a grinder.

Often, at the joints of the floor panels, the cracked plaster itself falls off and it only needs a little help in this, using a hammer, less often a perforator.

Advice! Scrape plaster off the ceiling with a trowel or long-handled scraper so you can work with both hands.

Special power tools make the work much easier - grinders (LShM, angle grinders, PShM) or special machines for removing plaster (such as Flex, AGP).

The use of a particular tool depends on the thickness, density, type of plaster and the required surface finish.

To remove plaster from facades of a large area, high water pressure units (HPA) are used, which can only be used by professionals.

If, after removing the old plaster, you plan to lay a new one, then the surface must be thoroughly cleaned with a metal brush, then primed and treated with an antiseptic.

Now you know how old plaster is. Those who have already encountered this work understand how difficult and unpleasant this process is, but, unfortunately, it is almost impossible to perform high-quality repairs to walls and ceilings without it.

Plaster repair

In the process of repairing an apartment, such a phenomenon as minor damage to the plaster is very often observed. They are formed due to various mechanical damage, as well as shrinkage of the walls.

Repair of plaster is carried out as follows: the old damaged plaster is removed by scraping with some sharp instrument, also grabbing some of the undamaged one. It is necessary to scrape everything down to the main layer. In the event that either the spray is still strong, it is allowed to leave them and apply patches only to the finish.

After the damaged part is scraped off and the surface is cleaned, it is necessary to apply some substance as a binder (for example, PVA) to the surface that remains, while grabbing the edges of the whole plaster.

It will be possible to continue repairing the plaster in about one hour, when the binder has already dried. Now it will be possible to finish the layer using standard technology.

When the main layers are damaged, they must be removed in order to exclude the option of peeling the repaired surface from the very base of the wall. You can assess the damage by the sound if you tap your knuckles on the wall. A dull sound is always made by peeling plaster.

Repair of plaster is carried out similarly to the plastering of still bare surfaces. Places where new plaster is superimposed on the old one must be carefully smoothed out to avoid various bulges or, conversely, depressions. To do this, the surface must be constantly moistened with water. Lastly, use a damp brush to run along the entire repaired surface to achieve a perfectly smooth and clean finish.

The repair of plaster also includes its grinding. This is done in order to remove various minor defects and finally level the surface. If the cover requires grinding, it must first be cleaned of whitewash, residues of paste or paint. After that, a solution is taken on lime dough with the addition of sand sifted on a millimeter sieve (proportions 1: 1), water is poured into this mixture until the density of sour cream is reached.

Do not use a lime-gypsum mortar, as in the process of prolonged mashing, this solution may lose its strength by frostbite. Also cement paste is not suitable. You can not use clean sand, as well as clean lime dough.

The next step in repairing plaster by grinding is to wet the wall with water. After that, it is necessary to apply a thin layer of the solution with a brush, which is then rubbed in a circular motion with a grater. If it (the grater) is covered with felt, then the quality of the grout will improve significantly.

If there are cracks, then they are cut 3-5 mm deep using a special plaster spatula. After that, moisten them with water and fill with a solution. It is better to fill with a spatula, the movements of which should be perpendicular to the crack itself. After that, align everything completely, moving with a spatula along the cracks.

When the smeared places dry up, they must be sanded with fine sandpaper. You can also level these places immediately after applying the prepared solution: use a grater for this.

By following these simple guidelines, you can repair the plaster yourself.

Repair of old plaster

Determining whether or not there is a need to remove the old layer of plaster is very easy. If the plaster is easily separated from the walls along with a layer of paint or wallpaper, it should not be left, even partially. If the destruction is not very noticeable, you need to test for strength by tapping on the surface of the ceiling or wall. If there is a dull sound, it means that the layer of plaster has lagged behind the wall in this place, and a complete void has formed there.

These defects, provided they are few in number, can be “cured” by cutting out empty spaces and then filling them with a new solution. This work is also carried out when installing windows and doors. For example, on ital-on.ru/catalog/ you can purchase high-quality doors, but whether they will serve faithfully depends on their correct installation in a well-prepared doorway.

How is the old layer removed? At the beginning, it is better to moisten the surface: this reduces the amount of dust, and wet plaster peels off more easily. If there is not much work, then you can use a spatula, hammer and chisel. But it is better to fully mechanize such a laborious process and arm yourself with a conventional puncher. A suitable nozzle and the "blow" function will relieve you of memories of the old finish in half an hour. If there is no puncher, you can use the grinder. It is necessary to apply a grid of cuts, and after that return to manual labor.

If the plaster layer is quite strong, but there are cracks on it, then it will be enough to fill all the recesses with mortar. Having slightly widened the edges of the cracks, they are well cleaned and moistened with water. After that, they can be filled (for this you can use a "syringe" from a plastic bag).

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Plaster in such places is beaten off with light blows of a hammer, a chisel or a blunt axe. Stains are removed from the remaining plaster. Rusty spots and soot are washed off with a 3% hydrochloric acid solution, and greasy stains are washed off with a 2% soda solution. To remove rust stains, a solution prepared from copper sulfate and water is also used. For 1.0 liter of boiling water, take 50-100 g of copper sulfate. The solution is used in a hot state, since the cold one gives a smaller effect. If with the help of these means the stains cannot be removed, they are painted over with oil varnish or whitewash.

After that, cracks in the plaster larger than 1 mm are cut with a knife to a width of 3-4 mm, the thinnest cracks are not touched, they are filled at the first priming. If the surface is smooth and previously puttied, it is enough to seal individual cracks and small potholes. The cleaned surface is washed with water. A rough and not previously puttied surface needs a solid putty.

Before plastering, the old plaster is well moistened with water so that the fresh mortar clings to the old one more firmly. Insufficient wetting between the old and new plaster may cause cracks. The mortar is carefully leveled with a long rule so that it is in the same plane with the old plaster. Pay great attention to the lapping of new plaster to the old one. With poor grinding, even a well-leveled and wiped solution will stand out from the general plane.

The gaps between the wall and the plinth are cleared, well moistened with water and densely filled with mortar. The solution that comes out is cut off, leveled and rubbed with a grater.

When repairing plastered walls, special attention should be paid to the junctions of partitions and walls. As a result of the precipitation of the house, cracks and crevices often form here. In such areas, it is necessary to clear cracks, beat off weak plaster and attach a metal or fiberglass mesh with small cells (usually 2x2). The mesh is installed in the corner of the junction of the wall and the partition in such a way that half of it adjoins the wall, and the other - to the partition. The metal mesh is reinforced with nails, and the fiberglass mesh is embedded in the plaster.

When repairing old plaster, the same solutions are used as for new plaster. Wall plastering in dry rooms can be carried out with lime mortar, and in wet rooms - with a complex one. If you want the repaired surface to be harder, add one part of gypsum dough to six parts of lime mortar. The gypsum mixture is prepared at the rate of 1.0 kg of gypsum per 1.5 liters of water. Gypsum dough is added to lime mortar immediately before use.

Damaged corners are best repaired with gypsum mortar, which hardens quickly. To do this, the remains of the solution are removed from the bare masonry, the seams are scraped to a depth of 20 mm, moistened with water, a gypsum mass is applied and it is well leveled. Plastic and metal corners are also used (to give strength to the corners). The joints between the old and new plaster are rubbed with a plastic trowel and a wet brush.

A certain difficulty is the repair of surfaces lined with dry plaster (for example: plasterboard sheets). Sheets of such plaster do not adhere tightly to the walls and sometimes break through in some places. In these cases, the damaged areas are expanded in the form of a rectangle or square. Then a patch of the same shape and size is cut out of a piece of plaster. After that, it is applied from the mastic and the prepared patch is glued onto it flush with the old lining. When the mastic sets, the seams are filled with the same mastic or putty and overwritten.

Surfaces lined with dry plaster sheets can also be repaired with lime-gypsum mortar. To do this, cut out the damaged area and tightly lay along the entire perimeter in the gap between the wall and the lined surface with an indent from the edges of the edges by 10-20 mm paper rollers-limiters. Then prepare the solution and apply it to the area to be repaired. Thanks to the rollers, the solution does not spread on the sides. It is leveled and rubbed so that the new plaster is flush with the previously finished surface.

With high-quality work, the surfaces of wet and dry plaster will turn out to be even. You can start painting or gluing wallpaper or sheets of flexible stone.

Do-it-yourself apartment renovation - repair of old plaster

Repair of plaster, application of plaster, repair of cracks in the ceiling and walls, repair and leveling of external corners, lapping of chamfer cut.

To begin with, we determine those places on the walls and ceiling where the plaster is already starting to crumble or just cracked. Often, old plaster falls off even when wallpaper or paint is removed, but it still does not hurt to check the entire coverage area.

It is most convenient to check for plaster weakness with a scraper or spatula. First of all, we check the joints of concrete panels and ceiling slabs, as well as the corners of the room.

The check is made by tapping the coating with the above tool. In those places where the plaster is weakly held, it will, if not crumble, then make a dull sound due to the fact that a void has formed under it. In these places, you need to remove the old plaster, and if it is a crack, make a V-shaped recess with a spatula. Detected and processed defects are smeared over.

How to fix cracks in the ceiling

Before you start patching cracks in the ceiling, it is necessary to thoroughly clean the place where the mortar will be placed again. Then this place should be moistened with water so that it is well saturated.

Fixing cracks in the ceiling produced in several stages and in small portions. At the first stage, the solution is placed on the very bottom of the V-shaped recess and smeared over its entire area. Before applying the second portion of the solution, it is necessary to allow the first to dry before hardening. The second portion of the solution must be applied in such a way that it fills the crack by 2/3. The second portion is also smeared over the entire area of ​​the recess.

After the second portion of the solution hardens, you can proceed to the last stage of crack closure. This time the solution is applied and rubbed flush with the ceiling surface.

It can be difficult for a non-professional to immediately measure the desired portion of the solution, and in this case, the following can be recommended: measure the first portion with an ordinary tablespoon. To do this, the solution is scooped up with a spoon so that it turns out with a slide, and sharply slaps on the right place. After that, you can lay the solution more carefully with a trowel or the same spoon and spread it over the entire area of ​​\u200b\u200bthe recess.

In order for the solution to be more plastic and hold stronger, you can add PVA glue to it in a ratio of 1:10. However, there is one point here - such a solution should be used as quickly as possible, since the setting speed of PVA glue increases significantly.

Also, PVA glue can also be used to prime the surface on which the plaster is applied. To do this, it should be diluted with water and applied with a brush, after which the first portion of the plaster should be applied immediately.

Applying plaster to the ceiling

In the event that you close up not a crack, but a part of a decent area ceiling, the solution should be applied in one layer. To do this, you need a special deck board, which should be slightly longer than the width of the repaired surface. It is better to paint such a board so that the solution does not stick to it, and it is even better to lay a layer of plastic film between the board and the solution.

The solution is applied to such an area that the deck board completely covers it, and is pressed against the board. To support the deck board, two spacer boards are used, which should be slightly longer than the height of the room. Spacer boards are installed between the floor and the deck board, supporting it from both sides.

How to fix cracks in walls

On the walls plaster repair must start from the bottom. First, defects that are at the bottom of the wall are plastered, and lastly, the junction of the wall with the ceiling.

Cracks on the walls are sealed in the same way as on the ceiling. It should only be taken into account that the solution must be applied from the bottom up. This is done so that the solution does not stick off as it is applied.

Repair of external corners

More attention should be paid to the repair of external corners. This is the most difficult task in wall plaster repair. The key here is proper preparation. Old plaster should be removed a little more than is required when repairing walls. In this case, it is necessary to make a ledge from below the processed surface of the corner in order to applied plaster Didn't fall off right away and held up better afterwards.

You need to do something like formwork. To do this, you can use a rail longer than the size of the defect. The rail is pressed vertically to the left side of the corner along the entire height of the defect and is supported by one or two boards (from the floor to the rail).

The area of ​​the defect before applying the plaster must be moistened with water. The plaster is also applied from the bottom up in three stages between the rail and the corner. Each subsequent portion of the solution is applied only after the previous one has dried. The formwork can be removed only after the solution has completely dried.

Alignment of external corners

After the solution is completely dry, you can start leveling the corner. Leveling is done with sandpaper, which can be wrapped around a wooden block for easier use. You can also level the corner with a pumice stone.

Alignment (lapping) of the outer corner after repairing the plaster is done as follows: you need to stand opposite the corner so that both walls that make up the corner are in sight. In this position, the result of the work will be clearly visible.

The hardest part about leveling the corner is chamfer lapping, that is, the direct junction of the walls. If the cut is uneven, then the angle will appear uneven. Therefore, if you can’t even grind the chamfer cut in any way, it’s better to apply it on a new one thin layer of plaster, and after it dries, grind until a good result is obtained.

You can align the outer corner with a special tool - a trowel for outer corners. This tool looks like a spatula, the working surface of which is bent at a right angle. However, in any case, the ideal result can only be achieved manual lapping.