Repair of old plaster of internal walls. Do-it-yourself repair and application of plaster, sealing cracks in the ceiling and walls Repair of old plaster
Plastering is one of the oldest and most reliable methods of leveling walls. In addition, plaster makes surfaces more durable. Although plastered surfaces last a very long time, they also need repairs, as cracks appear on them over time. In addition, the condition of the plaster is influenced by many factors - from the level of humidity in the room to the degree of exposure to mechanical loads on the surface (the plaster coating collapses faster in windows and doorways). In addition, frequent repairs to plaster are inevitable where poor-quality mortar was used or the walls were not carefully prepared for work. The tips described below will help you avoid mistakes during repairs. interior walls. By following the recommendations, you can forget about frequent repairs partitions in the apartment. In addition, they will become a reliable basis for any finishing material.
From time to time, walls finished with plaster need to be repaired, as they can become unusable due to dampness in the room or poor-quality mortar.
How to prepare walls for renovation?
Must be removed before repair old layer cracked and swollen plaster.
It might seem like a radical way to repair indoor walls complete replacement plaster, but it is unlikely that such an operation would look reasonable if, in general, the walls look good. New plastering may be necessary before laying tiles on a surface that was previously, for example, painted. But more on that later. In the meantime, if you are planning to only slightly update the partitions before wallpapering or new painting, it is enough to identify the most problematic areas of the surface. Cracks, for example, are visible to the naked eye, and “suspicious” areas can be checked by tapping them with a wooden or plastic mallet. A dull sound will immediately reveal where the plaster has come off the surface. In these places old mortar removed with a spatula. In this case, it is necessary to check what caused the detachment.
Perhaps, under the plaster that has separated from the wall, there is a surface that has not been properly prepared: there are traces of paint, grease marks or whitewash on it. All this will need to be deleted, otherwise the new layer will suffer the same fate as the previous one. The wall must be cleaned until the contamination is completely removed.
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How to deal with fungus?
Another factor in the peeling of the plaster layer from the wall may be fungus. Its appearance is most likely in rooms with high humidity and places of leaks.
The primary task in this case is to eliminate the causes of the fungus: insulate the walls, eliminate leaks, improve air circulation in the room.
If there is fungus on the wall, then a new layer of plaster cannot be applied until the wall is dried and treated with an antiseptic.
As for the removal of crumbling plaster, it must be removed not only in the area with clear signs the appearance of fungus, but also go beyond it by a few cm, removing the “healthy” solution around the affected area. It is worth adding that before deleting old plaster the treated area must be moistened. This is done not only to reduce dust, because fungal spores also fly freely with it. You also need to clean the base under the fungus-infected area as deeply as possible. If the wall is brick, then the masonry seams are cleaned 2-3 cm deep. All fragments that are not strong enough are removed from the concrete partition.
Further repairs to the plaster can only be continued after the wall has been thoroughly dried. And when the surface dries, it must be impregnated with fungicidal compounds that will destroy the spores remaining in the wall and prevent the appearance of fungus in the future. Once again, it should be recalled that antifungal treatment is effective only after eliminating the causes leading to its appearance.
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Crack Treatment
Treating cracks for subsequent plaster repairs looks much simpler. All crevices are moistened with water, after which the peeling fragments along the edges are removed with a spatula. Using tools, a kind of groove is made along the crack, narrowing inward. After cleaning, the cavities are treated with priming compounds that improve the adhesive properties of the walls being repaired. The primer is applied to all surfaces on which the plaster will be applied.
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What is needed at the preparatory stage?
The work of cleaning internal walls from defective plaster is best done with the following tools:
- spatulas of different widths;
- trowel;
- steel brush;
- construction hairdryer;
- perforator.
The latter can be useful if it is necessary to go deeper into a concrete partition to remove traces of fungus, and a hair dryer is used to remove it from the wall old paint(however, this work must be carried out in a ventilated area) and drying damp surfaces.
For impregnation of areas to be repaired, the following are used:
- plain water;
- antifungal solutions;
- primer.
They are applied to the surfaces to be repaired with a brush or spray.
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How to repair plaster?
Large sections of the wall require reinforcement.
Extensive areas with damaged plaster and the largest cracks require additional reinforcement. Reinforcing tape is placed in the cracks, and the area to be plastered is covered with reinforcing mesh. Areas adjacent to door and window boxes. It should be added that in deep and wide areas where repairs will be carried out, wall plaster is applied in several layers. The first of them is done by spraying with a liquid solution.
After it dries, another layer of plaster is applied to the wall, which must dry before applying the next one. Sometimes to repair a problem area it is necessary to plaster it in 3-4 layers. The last of them can be leveled with a rule, if its length allows it to rest on the edges of the cut surface, or with a trowel. It may be necessary to install beacons if the area to be repaired turns out to be too large (how to do this will be discussed below).
All defects on the walls are sealed with a mortar with the same type of composition, which was used to plaster them previously. It must be said that it is not worth preparing a solution with the maximum content of the binding component (cement). It won't improve that much strength characteristics plaster, how much will lead to the appearance of new cracks in it. For better plasticity, add glue (for example, PVA) to the solution. The solution for the finishing layer is made with a slightly lower content of the binder component compared to the previous ones.
If the partitions are lined with plasterboard or MDF panels, then the plaster repair can be completed, but before wallpapering the internal walls, the surfaces need puttying, before which the slightly hardened finishing plaster of the walls is treated with a block of polystyrene foam. With its help, small irregularities are rubbed out, and the surface becomes more uniform.
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How to repair walls in damp rooms?
Often the walls of many bathrooms, kitchens and toilets are covered in paint. Many homeowners have a desire to renovate these rooms and lay out their partitions with tiles. Plastering walls cannot be done over paint, so it will have to be removed. It has already been described above how the paint coating is removed. After this is carried out interior plaster, correcting surface defects and leveling it before laying the finishing material.
Do not forget that bathrooms and kitchens are rooms with high levels of humidity, so the likelihood of fungus appearing in them is quite high. To avoid problems in further exploitation these rooms, treat the walls with fungicidal agents.
High-quality leveling of walls is only possible when using a beacon profile. This stage of repairing internal walls can be considered the most labor-intensive, since it requires the most responsible approach to work.
To install beacons you will need:
- plastic dowels 4 x 60 mm;
- corresponding screws;
- beacon profile with fasteners;
- plumb line or level;
- hammer drill;
- drill-driver;
- synthetic threads.
Holes for dowels are drilled near the upper and lower corners of one of the walls. 2 vertical profiles are attached to the wall. The correctness of their installation is determined by a plumb line or level. Threads are stretched between the outer beacons, creating a plane for future plaster. The remaining profiles are attached with orientation towards these threads. The distance between beacons should be slightly less than the length of the rule. The same operation is repeated on the remaining partitions. Beacons can also be attached to walls using plaster.
The first layer of plaster consists of liquid solution, which is sprayed onto the surface, the next layers are stretched over it with a trowel, trowel or spatula. The finishing layer is leveled using a rule based on beacons. Excess mortar in the corners is removed with a corner leveler. Some time after leveling, the plastered wall is floated.
All connections, including those used in furniture production, can be divided into two categories: detachable and one-piece.
The latter constitute a special category, since special requirements are imposed on them. They work under conditions of temperature and humidity changes, which affects their durability and stability. And if detachable connections You can tighten or sort out, but with one-piece ones you cannot carry out such a procedure.
A little about the characteristics of D4 glue adhesives
In furniture production, adhesive permanent joints are mainly used. Since furniture is usually made from wood materials or derivatives of them, then appropriate adhesives are used. One of the most important criteria What characterizes the glue is its water resistance. So, glue D4 It is considered the most water-resistant compared to the others. This is all the more important because polyvinyl acetate dispersions, which are widely used as adhesive compositions for furniture, work even in tropical climates.
About gluing
The drying parameters of the glue during application are affected by temperature, humidity and the pressing force of the elements being glued. More heat reduces the time required for compression, and humidity increases it.
Another point is the humidity of the surfaces being glued. For most moisture-resistant adhesives it should be between 7 and 10%. That is, the surfaces must be dry.
A little physics
The physics of the process is such that during the absorption of moisture, the adhesive layer swells, and during evaporation and recoil, on the contrary, it dries out and loses in size. Such fluctuations lead to glue line“dries out” and loses strength and geometric stability. Essentially, these cyclic vibrations lead to the destruction of the joint and the furniture as a whole. This is why the moisture resistance of the glue is so important.
ABOUT THE PROCESS OF ADHESION USING D4 GLUE
When gluing, it is advisable to reduce the gap between the parts to a minimum, since a large tolerance and an increase in the glue layer reduce the strength of the seam and increase the drying time. Glue is applied to one of the surfaces and the surfaces are pressed against each other. It also doesn't hurt to clamp them with a clamp. The seam gains its final strength and water resistance after 7 days. As a rule, glue does not change the color of the wood, but contact with metal should be avoided, since, together with the tannic acids of the wood itself, it can change its color. The adhesive layer itself can also be painted.
I would be grateful if you share the article on social networks: April 23, 2014The walls have begun to crumble, the plaster is falling off in pieces - all this can be fixed!
Let's break the process into two stages. Let's start work with preparation for wall repairs, and the repair work itself.
First stage. We will remove damaged sections of the walls. As a tool, you can take: a hammer, an ax, a scraper or an electric hammer.
The preparation process itself is very dusty, so it is worth wearing dust protection. Working clothes won't hurt either, especially good gloves.
When removing plaster that has reached the end of its useful life, it should be done with small blows to the wall. Cases where neighboring areas disappear on their own cannot be avoided in any way. Therefore, we carry out the work according to the easy principle - what is missing is gone. There is no need to feel sorry for old plaster.
Having covered all the wall defects, you can begin priming the walls with a special compound that can be purchased at any hardware store.
Primer is necessary special tools, a roller or brush is best. You need to saturate the walls carefully, allowing the composition to be well absorbed into the base and adhere to the wall. After finishing the priming process, let the treated walls dry.
The preparation process is completed, you can move on to the next stage of wall repair.
Second phase. This stage is completed by sealing defects in old plaster with special mixtures and solutions.
Determine which mixture is suitable the best way, you can know the thickness or volume of damaged sections of walls. In a hardware store, sellers will provide a short consultation on selection the required material for repair.
Solutions for wall repairs must be applied with narrow-purpose tools. The following types of tools are suitable for this stage of work: spatula, half-grater, trowel, rule.
The prepared mixture is applied in two or three stages, each stage includes complete drying of the solution and the application of a mesh for reinforcement. It is necessary to reinforce the walls to obtain further good results.
The last process of wall repair will be grinding the applied mortar in damaged areas of the walls. We will need: sandpaper or mesh with abrasive coating. Sanding walls, necessary stage completion of damage repairs. It is not always possible to cover the areas of the walls being repaired evenly; this requires sanding.
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Plaster is one of the most popular facing coatings. However, if it was grossly violated technological process or negligence in operation, damage occurs of various nature: cracks, shedding, peeling.
From this article, the reader will learn why plaster cracks when it dries, the causes of defects and methods for eliminating them. As well as the sequence of processes for repairing the plastered surface of walls, both inside the building and the facade.
Technological causes of defects
Violation of proportions when preparing the solution or technology for its application, as well as errors in preparing the base, lead to the following defects.
| Defect | Cause of occurrence | Repair method |
| Blistering of the plaster surface, the appearance of small tubercles | An unseasoned lime mixture with unslaked particles was used | Let the solution sit until the lime is completely extinguished, reveal the defects, moisten the surface generously with water, fill the cavities with the solution and grind. |
| Sedimentary cracks | Poor mixing dry plaster mixture, using a solution with an excess of binder for the cape | Accurately follow the proportions and dosage indicated on the package, mix thoroughly using a construction mixer |
| Peeling a fresh sketch from the base | The base is not rough enough, very dirty and dusty, the surface is excessively dry | When repairing facade plaster, the technology involves notching or filling shingles, the surface is cleaned and dust-free with damp sponges and additionally moistened with water. |
| Propagation of cracks throughout the entire depth of the plaster layer | The base material is not rigid enough, at the points of contact between two monolithic structures no reinforcing mesh | Each subsequent layer of finishing should have slightly less strength than the previous one (add less binder to the mixture), the intermediate layers should not be allowed to dry out, and before plastering, moisten the base generously with water |
| The appearance of efflorescence, spots and streaks on the surface when drying | Applying plaster to a wet surface (especially important for external walls) | Plaster only dried walls, prevent “pull-up” of moisture from the ground by making appropriate waterproofing |
At local repairs wall plaster in some places cracks and potholes are cleaned of crumbling particles with a stiff brush, then the exposed surface is generously coated with primer deep penetration. The complete drying time is indicated on the packaging and different manufacturers it may vary, although it rarely exceeds 3-5 hours.
Repairing a crack before repair
The covering layer applied to the cracks is rubbed neatly, flush with general level, it is advisable to prevent the solution from spreading over the previously treated surface.
Fresh plaster with small cracks, scattered at a slight distance from each other, is rubbed over the entire area. To repair monolithic plaster, a cement or lime-cement mixture is diluted. Sand of fine fractions with a grain size of 0.3-1.2 mm is used as a filler.
Cleaning, dust removal of cracks
Important: When repairing, gypsum cannot be used in grinding solutions, as it loses its properties during the process. As a result, the surface may fall off in layers.Repair of plaster of internal walls by rubbing the surface:
- The surface is wetted with water;
- Put a little repair mixture on a grater;
- Apply to the surface of the crack in separate strokes;
- The grater is cleaned, moistened with water, work area spray with a brush;
- The solution is distributed in a thin layer over the crack using a grater in a circular motion.
Cracks appear when drying
There is another possible reason why gypsum plaster cracks when it dries. The point is non-compliance with temperature and humidity conditions. 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 gypsum plasters Knauf companies must dry at a temperature no higher than 18-20°C, and humidity: walls up to 8% and air 40-55%. It is very important not to provide intensive ventilation in the room.
Surface cracked due to drying out from overheating
For cement compositions drying speed at optimal rates external environment the other, moreover, strongly depends on the type of base. There may be many more options for why the plaster on the walls is cracking.
Sand-cement and heavy decorative plaster on brick and concrete base to avoid cracking it should dry at a temperature of 15-25°C and relative humidity air no more than 75%. At the same time, the duration of drying depends on the wall humidity of 5-15%, up to a quarter of the entire period. Therefore, a 2 cm layer can dry from 18 to 30 hours.
Important: To avoid cracking of the plaster after finishing work, the temperature and humidity conditions in the room should be strictly observed.Local defect repair
Grouting cracks with repair compound
Repair of old plaster is carried out in several stages:
- Checking the surrounding layer, removing the lagging part;
- Cleaning and widening of cracks;
- Primer;
- An intermediate layer of repair composition is applied to the crack 2-3 mm below the general surface of the wall;
- While the mixture has not hardened, a mesh is applied to its surface with a spatula to improve the adhesion of the decorative layer;
- 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 repair decorative plaster with a uniform pattern.
Important: restoration or repair Venetian plaster much more complex, since it has a multi-colored surface with a chaotic pattern. In case of noticeable, albeit local, cracks, it is recommended to finish the entire wall.A hole appears.
It can be large or small - a piece of plaster falls off, a hole is made that becomes through, a hole is mistakenly drilled with a hammer drill in the wrong place.
After this, fixing a hole in the wall is a headache and the responsibility of either the owners or the repairmen.
They can be divided by size - large and small.
Large holes will require significant volume.
Most likely, in this case you will have to finish the entire surface of the wall in order to hide it again.
Fix a hole in the wall small size much easier.
Here you can limit yourself finishing works local scale.
For large holes, it is necessary to fill the hole using stone materials.
How to repair a hole in this type of wall? Best of all is what the wall was made of before. For example, for brick wall sealing with brick is suitable, for a wall made of aerated concrete you can use. For a tongue-and-groove wall, take a piece of a tongue-and-groove block. For concrete wall take the brick.
The material for laying in the hole is selected taking into account the material from which the masonry is made. For brick and aerated concrete you can take cement mortar and place the piece covering the hole on it.
For a tongue-and-groove ridge, be sure to take gypsum masonry mortar. Be careful - it hardens quickly! You should not use rotband and other gypsum plasters for this purpose - the adhesion will be fragile. But the fine-grained ones gypsum putties, such as a fugenfüller, you can take them - they will adhere well to the tongue-and-groove block. In this case, it is advisable not to make the layer thicker.
Before you start filling the hole, try to line up the edges, especially the bottom. This will avoid problems with . You can level it with a chisel or a hammer drill. Be careful not to completely gouge the wall or break too much. It is also advisable to trim the edges. It is convenient to fit a piece of block or brick under the hole using a stove hammer, making gentle blows and breaking off small pieces.
If it is a plasterboard wall, such as a multi-layer partition, screw a piece of plasterboard from inside the main one. This is done like this:
- Cut out a piece of drywall larger than the hole, 3-4 centimeters in all directions, then cut it in half.
- Screwed to the front side of one cut piece door knob on self-tapping screws.
- The sheet is inserted behind the main cladding and screwed on the outside with self-tapping screws. The handle is unscrewed.
- Also screw the second half, joining an even seam approximately in the middle of the hole.
After the hole in the wall is sealed, the masonry has dried and finally set, plastering work is carried out.
How to repair fallen plaster
Small-scale plastering work will have to be carried out as after stone works after filling holes, and after the plaster has fallen off from a small area.
The easiest way to do this is to use quick-hardening gypsum plasters.
These compositions allow you to immediately apply a large layer, especially in a local area, and not have to wait long for the plaster to set.
What is the best way to seal a hole in the wall using gypsum compounds?
The most common such composition is the rotband. The time it takes for it to fully set is about three hours, and for complete drying to take place – about a week (depending on the air humidity in the room).
You can use plasters from other manufacturers. It is better not to use pure alabaster - it gives unpredictable adhesion to the surface and then it is unknown how it will lie on a large alabaster platform.
Before filling the hole, it is cleaned. Take out all the pieces that fall off and move, sweep away the dust with a brush. The surface is moistened, primed with compounds intended for plastering works. After this, a layer of plaster is applied.
It is more convenient to do this when filling holes using a small ten-point spatula. Apply until the entire surface is filled to the plane of the wall. After this, the layer, while it has not yet set, is carefully cut off according to the rule, flush with the main wall.
Acrylic sealant is good because almost any paint fits well on it and sticks to it.
How to make a defect invisible
For small defects sealed with sealant, you can make them invisible using a small brush and paint.
Just paint over it white sealant on the edge of the resulting hole with a brush.
It is advisable to match the paint by color, but if it does not match too much, it is not a problem.
In a small area this will not be very noticeable.
For larger defects, full finishing is carried out.
If the defect is on the wallpaper, it is necessary to putty the defect and align it with the rest of the wall, and then replace the sheet, carefully cutting it along the adjacent wallpaper. If the defect is on a painted wall, it is filled with putty and painted over.
In this case, you need to very accurately select the paint color to match the base color. If on a tile, several tiles are placed at the site of the defect. If it is not possible to hide the defect, do it again exterior finishing the entire wall.
How and with what to seal the grooves is shown in the video:
