Repair of wall plaster is an operation necessary when, in some places, it begins to crack and move away from the masonry. Most often, cracks and chips appear near window frames and doorways, but sometimes defects appear in other places as well.
If cracks are clearly visible on the surface of the plastered walls, then delamination is not easy to notice. Bloating appears in certain areas, and when tapped, the layer of plaster collapses and falls. The reasons are varied, but the most common is improper surface preparation before applying the plaster mixture.
Preparatory work
The swollen layer must be removed Repairing old plaster does not require the complete removal of the previous layer. It is carried out in small areas where damage or detachment is found.
If the area of the wall section to be repaired exceeds the length of the rule, then it is necessary to install construction beacons.
In cases where the area of the damaged surface is rather small, the edges of the previous coating act as beacons.
Before proceeding with surface restoration work, it is necessary to identify all existing defects.
To do this, during the preparation process, all detected cracks are sewn up using a spatula, and all suspicious places must be tapped with its handle.
Where the sound is dull or the swelling of the old one is noticeable, they beat off the damaged layer with a hammer, remove it with a spatula, exposing the masonry.
When repairing old plaster in large areas, it is required to perform reinforcement using a mesh netting for this purpose, which is attached to the wall using self-tapping screws or special fungi.
Reinforcement
The solution must penetrate under the mesh Wipe the surface with a wooden or plastic float in a circular motion, having previously moistened the tool with water.
- a thing is not eternal. The owners of houses and apartments face a problem when it begins to crack or fall off in places. What to do? We will consider the reasons for this phenomenon, as well as how to repair the plaster of walls in separate places and the technology of surface restoration.
Defects on the surface, causes and method of restoration
There are a number of defects that are formed when the proportions of the components of the composition are violated, or the technology of its application. The list is as follows:
- Lump formation and swelling.
- Sedimentary cracks.
- Fresh plaster is peeling off the wall.
- Cracking along the entire depth of the solution.
- Efflorescences, spots and stripes appear on the wall after the plaster layer has dried.
What is the cause of these defects? Swelling and bumps may appear if the limestone composition is unstable and has unqualified particles. How to repair lime plaster in this case? It is necessary to cure the plaster until the lime is completely extinguished. Defects are opened, abundantly moistened with water and filled with plaster mortar. It remains to wipe the surface.
Sedimentary cracks are formed with poor mixing of the composition and with an excess of binder. The exact proportions and dosage in accordance with the packaging will help to solve the problem. It remains to thoroughly mix the plaster and level the surface.
When the substrate has not been prepared, cleaned, rough, too dry and dusty, fresh plaster may flake off when sprinkled. To solve it, you will need to suspend work and start preparing the surface. The application technology is as follows: notches are made on the surface for better adhesion (or shingles are made), the wall is cleaned of dust and dirt. In addition, it is moistened with water. Then the mixture will not flake off, and the repair of plaster and surfaces inside the building will not be needed for a long time.
If the problem lies in cracks throughout the entire thickness of the plaster layer, then there is exactly one reason - there is no reinforcing mesh between the wall and the plaster. The base material is not rigid and is not reinforced with anything. The technology for applying the mixture lies in the fact that the subsequent finishing layer should be less durable than the previous one, that is, there is less binder in its composition. So that the intermediate layers do not dry out, they need to be moistened with water and reinforced with a mesh.
The last defect is spots and stripes. They most often appear on the outside of the walls. This could be due to a very damp or wet surface. Especially when the plaster is applied after rain. The solution is to process the dried walls, make waterproofing, so that moisture does not pull up from the ground. Local repair of plastered walls is done differently. The technology is simple, but requires careful consideration.
Step-by-step instructions for eliminating defects
Do-it-yourself repairs to a wall with pieces of plaster that have fallen out. The work is not difficult. You just need to follow the instructions. Alternatively, you can completely remove the layer and apply a new one. But it is more profitable to plaster the damaged areas. It all starts with an inspection. It is important to identify areas that need repairs. A wooden mallet is required. We'll have to lightly tap the wall. If a dull sound is heard, then the composition has departed.
- After the examination, the old plaster must be removed. We do not touch the places where it holds well.
- Next, the seams are cleaned if it is brickwork. The surface is cleaned of debris and dust.
- A primer is applied to the wall. It is needed for better grip.
- After the surface has dried, the wall is slightly moistened and the solution is applied. If most of the wall has peeled off, then you will have to use beacons and a rule. This is the only way the wall surface will be perfectly flat.
- For minor damage, plaster is removed in the form of a square or rectangle. The site is processed according to the method described earlier, and the cavity is filled with the prepared composition. It is important to stick to the proportions so that the mixture has the correct consistency.
- Another restoration option is restoration with corks. In the right places, a hole is drilled to the base, primed, filled with mortar and plastered.
Note! For wooden walls, use a limestone mortar. However, it is not suitable for wet surfaces. Better to resort to a cement mixture. The corners are recommended to be treated with gypsum plaster, as it sets faster.
Restoration work
Repairing plaster also involves removing stains from the surface of the wall. They appear during operation and can be from grease, soot or rust. It also happens that the spots were formed before finishing work. In this case, you will have to solve this problem before you start gluing wallpaper or laying tiles. The restoration work is as follows:
Advice! Whichever surface you are cleaning, it is important to first clean it of dirt and dust. Only after that other manipulations are performed.
The restoration of the surface under the tiles requires special attention. The procedure is as follows:
- using a rubber mallet, the surface of the wall is tapped. This is the only way to determine a peeled or poorly fixed area;
- when the site is found, you need to knock harder so that the tile falls off. If it is not removed in this way, then you will have to act radically - to break it. The process requires accuracy: the tile is broken from the center so that the adjacent one is not damaged;
- if after removal a solid layer of plaster remains, then it is not necessary to knock it down. It is necessary to more reliably glue the new tile using special glue;
- when the plaster falls off, the place is cleaned, primed and plastered again. After drying, a new tile is glued.
Removal of cracks
Removing on the surface is much easier. Repair of wall plaster in this case consists of two stages: surface preparation and plastering. To begin with, the cracked wall is cleaned of old cladding material and dirt. After that, a primer is applied to the surface. When it is dry, you can start stripping to give the wall a smooth finish.
Section of a wall reinforced with mesh Then the plaster is mixed and applied to the surface with a thin layer. The composition is leveled with a spatula. In the presence of large cracks, it is better to reinforce the structure with a reinforcing mesh. With it, the plaster layer will be much stronger and will not crack.
Conclusion
Peeling plaster is a small problem that can be solved by hand. No need to redo all the work. It is worth carrying out restoration work, which will take a maximum of one day, a plaster mixture, a primer and a trowel with a rule. Even with cosmetic repairs, it is recommended to remove the old solution so that it does not fall off along with the finish during operation. Stains and cracks also need repair. Then you can be sure that the finish will last for many more years.
Renovation of plaster, application of plaster, filling of cracks on the ceiling and walls, repair and leveling of external corners, lapping of the chamfer.
To begin with, we determine those places on the walls and ceiling where the plaster is already starting to crumble or is simply cracked. Often old plaster falls off even when the wallpaper or paint is removed, but it still does not hurt to check the entire coverage area.
It is most convenient to check for the weakness of the plaster 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 carried out by tapping the cover with the above tool. In those places where the plaster is weak, it will, if not crumble, then emit 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 in the event that it is a crack, make a V-shaped depression with a spatula. The detected and processed defects are covered up.
How to repair cracks in the ceiling
Before you start repairing cracks in the ceiling, it is necessary to thoroughly clean again the place where the solution will be laid. Then this place should be moistened with water so that it is well saturated.
Repairing 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 depression and spread over its entire area. Before applying the second portion of the solution, it is necessary to let the first one dry until it hardens. The second portion of the mortar 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 depression.
After the second portion of the solution has hardened, you can proceed to the last stage of filling the crack. This time the solution is applied and rubbed flush with the ceiling surface.
It can be difficult for a layman to immediately measure out the required portion of the solution, and in this case, we can recommend the following: measure the first portion with a regular tablespoon. To do this, the solution is scooped up with a spoon so that it turns out with a slide, and is sharply slapped onto the right place. After that, you can lay the solution more accurately with a trowel or the same spoon and spread it over the entire area of the recess.
In order for the solution to be more plastic and hold tight, you can add PVA glue to it in a ratio of 1:10. However, there is one point - such a solution should be used as quickly as possible, since the speed of its setting increases significantly from PVA glue.
Also PVA glue can be used for priming the surface on which the plaster is applied. To do this, it should be diluted with water and applied with a brush, and then immediately apply the first portion of the plaster.
Ceiling plastering
In the event that you are not patching up a crack, but a decent part of the area ceiling, the solution should be applied in one layer. For this you will need a special shuttering board, which should be slightly longer than the width of the surface to be repaired. 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 mortar is applied on such an area that the formwork board completely covers it, and is pressed by the board. To support the shuttering boards, two spacers are used, which should be slightly longer than the height of the room. Spacer boards are installed between the floor and the shuttering board, supporting it on both sides.
How to repair cracks in walls
On the walls repair plaster you must start at the bottom. First, the defects that are at the bottom of the wall are plastered, and last of all, the joint between the wall and the ceiling.
Sealing cracks on the walls is done 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
You should dwell in more detail on the repair of external corners. This is the most difficult task when repairing plaster on the walls... The main thing here is correct preparation. Old plaster should be removed a little more than is required for wall repairs. In this case, it is necessary to make a step from the bottom of the processed corner surface in order to applied plaster did not fall off immediately and held on better afterwards.
Something like formwork needs to be done. 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 must be moistened with water before applying the plaster. The plaster is also applied from bottom to top in three steps between the strip 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 mortar has completely dried. 
Aligning the outside corners
After the solution is completely dry, you can start leveling the corner. The alignment is done with sandpaper, which can be wrapped around a block of wood for more convenient use. You can also level the corner with a pumice stone.
Alignment (lapping) of the outer corner after plaster repair is done as follows: you need to stand opposite the corner so that both walls that make up the corner are in the field of view. In this position, the result of the work will be clearly visible.
The hardest part about aligning a corner is lapping chamfer, that is, the direct junction of the walls. If the cut is uneven, then the angle will appear uneven. Therefore, if you cannot evenly grind the chamfer cut, it is better to apply it on a new one thin layer of plaster, and after drying, rub in until a good result is obtained.
You can even out the outer corner with a special tool - the trowel for the outer corners. This tool looks like a spatula, the working surface of which is bent at right angles. However, in any case, the ideal result can only be achieved hand lapping.
The plaster is crumbling, what should I do? It happens that, saving on cement, builders make plaster practically from sand. And this material is used indoors and for external wall decoration of any structure.
Plaster increases the strength of the wall by almost 30 percent, which is very important, and only then the owners decide for themselves: paint the walls, decorate them with tiles or glue the wallpaper. In addition, such a coating helps to level the walls, hide defects on them and ideally prepare surfaces for applying liquid or gluing ordinary wallpaper.
The plaster can crumble from high humidity in the room if the technology was violated during its application or a poor-quality solution was used. In order for the plaster to hold firmly, it is better to entrust the work to an experienced master.
If the walls of the dwelling are plastered with an old cement-sand mortar (see.
- Strengthen. This method is used if the coating only crumbles. In this case, it is enough to apply a deep penetration primer to the old plaster before starting the putty or to treat the wall surface with concrete contact, which should fix the surface well in cases where the primer cannot cope with this.
- Use a more radical method - completely remove the coating... This method is used if the plaster is crumbling. This usually occurs due to non-compliance with the technology during its application or from the wrong temperature regime, when the temperature in the room is very low.
For this you need:
- strip off all old plaster (see How to remove old plaster from walls without problems);
- treat walls with a primer;
- putty everything in a new way.
After that, the topcoat can be applied. In this case, the price of work will be higher, but the result will be better and more reliable.
Which method to choose, everyone decides for himself, the main thing is to determine when the plaster will become unusable. In principle, plaster should not have high strength - it is just a finishing material, and not a supporting element of the building.
How to repair plaster
Advice: If you are not confident in your own abilities or you have never had to plaster walls before, you should trust the professionals. They will complete the entire process faster and better than a self-taught amateur.
Plaster repair is carried out in several stages. To isolate the surface of the wall from moisture, you will need to apply a protective compound, and then proceed with further operations.
The repair procedure is as follows:
- The wall is carefully and neatly scraped out with a metal brush from all remnants of the old plaster.
- A special primer mixture is applied in two layers.
- The stains remaining after the primer has dried are lightly washed off with a stream of water.
- The wall dries for about three hours.
Tip: If the defects in the coating are very serious, the damaged areas should be reapplied with a putty mixture or plaster.
- The coating to be applied should be about three centimeters thick.
- When the wall is putty, the powder dissolves in water and is applied in a small layer.
- The first layer is performed to level the wall (see Aligning walls with plaster according to all the rules).
- After one hour, a second layer is applied superficially.
How to strengthen plaster
For work you will need:
- Primer.
- PVA glue.
- Wallpaper glue.
Instructions for strengthening cracked, flaking or crumbling plaster:
- To avoid such defects, the plastered surface must be reinforced with a primer. Such a coating is an important condition for the performance of good quality finishing and repair work. It is used for finishing the surface of walls and ceilings before applying paint, gluing wallpaper and tiling. A primer is a mixture of a solvent, a component for a binder and various additives that determine its properties. The dried material creates an opaque film of the same thickness, which increases the adhesion or adhesion of subsequent layers of the coating.
- According to their purpose, primers are subdivided for application into:
- metal surfaces;
- wooden surfaces;
- universal, with an acrylic base. Acrylics are used for concrete, cement and gypsum plaster, wood and fiberglass wallpaper. Such compositions dry quickly, they do not have a pungent odor.
- The impregnating compound is applied with a roller, in one layer or with a wide paint brush.
- When decorating rooms with high humidity: bathrooms, showers, special compounds are used, they create a layer of waterproofing. For example, for dry rooms and with high humidity, Aura Primer is suitable. The mixture is diluted with water just before use in a ratio of 1: 4. The dilution ratio can be reduced to 1: 6 to increase moisture protection.
- Plaster reinforcement can be cheaper with wallpaper glue. This method is often used before wallpapering. With high-quality glue, the adhesion is strong, the wallpaper along with the putty will not lag behind. But this option does not apply to vinyl heavy wallpaper.
- An unjustified economy is the use of PVA glue for a primer, especially in rooms where there is high humidity. The glue contains dry components in its composition, they are able to absorb moisture, which, after staining, can contribute to the appearance of matte spots, due to the uneven absorption of the paint.
How plaster is strengthened by impregnations
Today manufacturers produce high-quality "strengthening" impregnations in plastic containers. Before use, the liquid is poured into a convenient container, then it is applied to the plaster with brushes or rollers.
Some types of compounds penetrate more than a meter into plaster and concrete. At the same time, they close the pores at the chemical level, transform the material, bind even microscopic particles together.
After strengthening the plaster with impregnations, cracks will not form, the coating will cease to crumble. It is quite simple to use this method with your own hands to strengthen the surface.
In addition to using special impregnating compounds, the plaster can be strengthened using a reinforcing mesh, and then putty. The option of strengthening the plaster is selected depending on the situation and goals.
How to reinforce the plaster with a reinforcing mesh
In more difficult cases, a reinforcing mesh is used to strengthen the plaster. In this case, the plaster layer is very badly destroyed, as can be seen in the photo.
Tip: A mesh for strengthening the plaster must be used metal, preferably stainless steel. After it rusts, traces of rust can break through the thick coating layer, resulting in additional rust control costs.
With this method:
- The mesh is attached to the wall in any way: dowels or nails, depending on the material of the wall.
- A new coating layer is applied on top not too thick. The main thing is that the mesh is closed.
Details of strengthening the plaster are shown in the video in this article.
It often happens that when preparing an apartment for renovation, it turns out that all the walls are in holes and resemble Swiss cheese. Holes and grooves remain from old wiring, nails for cabinets and shelves, former sockets and switches, and just from plaster that has fallen off with a piece of the wall. The ceiling window to the bathroom is also an eyesore. But it is not for nothing that they say that the eyes are afraid, but the hands do. Let's roll up our sleeves and start sealing the defects, especially since there is nothing complicated here.
Close up small holes
First, we clean small holes on the wall from screws or dowels with a nail of a smaller diameter. We blow it out with a compressor to drive out dust from there, we moisten it abundantly with water to equalize the moisture content of the surface and the damp repair compound. Fill the resulting holes with putty to the maximum depth. The final touch is sanding flush with the main surface.
What to do with an average hole in the wall?
Sealing a hole from an old outlet or neatly removed utility pipe is not much more difficult than getting rid of a small hole. The surface treatment principle is the same:
- We remove all parts falling off the wall. Including suspiciously wobbling ones - they can bring a lot of trouble after the completion of the repair.
- Using a brush or a vacuum cleaner, remove the crumbled pieces and dust.
- Spray the surface abundantly with water from a spray bottle.
- For better adhesion of the mortar to the wall, it is necessary to use
- We fill the hole with a solution of sand, cement and water (3: 1: 1) or use a ready-made plaster mixture, let it dry.
- We control the drying process: if cracks appear, rub with a primer, leveling the surface. We dry it, and then, if necessary, repeat the priming.
- Finish leveling with a sander or manually using medium-grained sandpaper.
- After complete drying, it can be considered that the hole is closed and the surface is ready for finishing.
Drying of the solution takes at least 12 hours. At this time, no manipulations with the treated surface can be performed.
Through holes from pipes are pre-supported on one side with a piece of plywood. Having covered the surface on one side of the wall, we carry out the procedure on the other in the same way.
How to close a large hole?
Sometimes it happens that when repairing walls, not only pieces of plaster fall out. They can be joined by chipped pieces of concrete or brick. In this case, it is necessary to use additional reinforcement of the wall surface.
- Similarly to the previous cases, we clean the hole from all that is superfluous.
- We drive in dowels or screw in powerful screws. If the pothole is large enough, additional wire may be required.
- We remove debris and dust with a dry brush or vacuum cleaner.
- We wet the surface with plenty of water.
- Add broken brick or crushed stone to a standard cement-sand mortar.
- With the resulting mixture, we close up the fallen piece of the wall, let the solution stand and dry.
- If necessary, plaster the surface of the entire wall or locally a section of the hole, followed by drying and rubbing the cracks.
- Now you can start finishing.
The cement mortar should be applied in thin layers, allowing them to dry thoroughly. The thick layer is guaranteed to crack or fall off.
What to do with large holes in the wall?
After careless dismantling of pipes, large holes remain in the walls. To restore the integrity of the surface, you will first have to lay the main part of the break with a brick. We widen the hole so as to make the masonry even. Then we lay out the brick on the mortar as the main patch. Further manipulations are performed according to the algorithm described above.
Removing holes in drywall
Carefully remove a small piece of old wallpaper around the hole. On a wet surface, apply gypsum diluted with water with a knife. Glue a new piece of wallpaper over it. You can also stick a decorative applique on the damaged surface.
If the gypsum board is damaged by the "fallen" locker, the repair algorithm will be as follows:
- Around the hole, draw a square or rectangle with a pencil, capturing the cracked surface.
- Use a hacksaw to cut a hole along the marked lines.
- From the seamy side, we fasten two parallel tires to the drywall with screws, on which the patch will hold. The number of tires increases depending on the size. As a frame, you can use wooden slats, durable plastic, metal profile.
- Transfer the outline of the cut piece to a new sheet of drywall and cut it out as accurately as possible.
- We fix the patch to the rails previously screwed to the wall, driving the screws so that the caps do not protrude above the surface of the sheet.
- We seal the seams with plaster putty.
- We remove the irregularities with sandpaper.
- Further priming is carried out either in the area of the former hole, or on the entire surface of the wall.
There are times when the damaged area is too large. In this case, we calculate what is cheaper and easier - to repair a piece or replace the whole sheet.
If the plasterboard wall is not broken through, but only slightly pressed in and cracked, there is another way to seal the surface: we glue it on the damaged area, and then rub it with a repair compound. After drying, level the surface with a sandpaper.