The beauty and neatness of any interior depends on many aspects, and walls play a big role in the design of the room. It is known that over time they appearance may suffer under the influence various factors. In this article we will look at what to do if the plaster has come off the walls, as well as the reasons for this phenomenon.
All possible damage plasters can be divided into 2 types: technological and operational. Below we will take a closer look at each of the categories.
Technological disadvantages
They can occur as a result of a violation of the technology for preparing the solution, as well as as a result of improper application of the coating to the wall. These defects include the following:
- Bloating. One of the reasons that your plaster is falling off is the incorrect composition of the solution. If you use uncured lime, which contains unslaked particles, to prepare the mixture, it can cause small swollen tubercles to form on the walls. Over time, these voids lead to deterioration of the coating. In order to get rid of this problem, the area where bubbles form must be cleared of the plaster and a higher quality mixture must be reapplied.
- Cracks. This phenomenon occurs when you use insufficiently mixed or greasy solutions. Fatty formulations are those that include a lot of astringents. The appearance of cracks is also promoted by drying the wall surface too quickly. To avoid the occurrence of such defects, you need to carefully monitor the ratio of all components in the prepared plaster, and in addition, mix the mass very thoroughly before using it. If you are treating walls in hot weather, you should prevent them from drying out too quickly. To do this, the surface must be moistened periodically. If cracks do appear, they can be eliminated by rubbing the wall with mortar or plaster paste. Very large gaps must be widened, cleaned, wetted and sealed with plaster.
- It happens that the plaster comes away from the wall as a result of peeling. This problem can occur for two reasons: if the mortar is applied to a wall that is too dry or to another mortar that is less durable. To get rid of such a defect, the area with the peeling coating must be cleaned, thoroughly wetted and re-coated with the composition. Remember that before starting such work, you must carefully inspect the entire wall and determine in what other places the coating is peeling off. When preparing the mass and applying it to the wall, it is important to remember that the strength of the composition should change in decreasing order. That is, the first layer of solution should be stronger than the subsequent ones.
- Swelling. Unlike peeling, this problem occurs as a result of applying plaster to an excessively moistened surface. To eliminate this defect, the affected area will have to be cleaned, the wall dried and re-coated with mortar.
Operational defects
Another reason why plaster falls off is damage caused by aging of the coating. Such defects include the same cracks and peeling, only they do not appear immediately, but after a long time. To prevent the appearance of defects or eliminate them in time, you need to regularly inspect the coating and make repairs if necessary.
Plaster repair
So, your plaster has fallen off, what should you do in this case? The main way to combat this problem is to carry out repairs, which begin with removing the old coating layer. In order to carry out such work, you will have to acquire a suitable sharp tool that can be used to scrape off the old mortar from the walls. Remember that when clearing a specific area, you will also need to cover a small area around it. Let's look at the process of eliminating plaster defects in the form of a sequence of actions:
- First, the damaged area must be cleaned of old plaster. This can be done by tapping, as a result of which the loose coating will simply fall off the wall.
- From all the seams of the exposed masonry, you need to scrape out the mortar to a depth of at least 1.5 cm. After this, the treated area is swept from dust and moistened with water.
- Then you should prepare the liquid cement mixture and cover the wall with it.
- When the soil layer hardens, you need to do mortar. If you want your wall to dry faster, add a little gypsum dough to the resulting composition. the following proportion: for 6 parts of solution, 1 part of gypsum dough.
- Cover the surface to be treated with the resulting composition and rub in with a trowel. Treat the boundaries of the old and new coatings with adhesive paint and rub them in the same way.
- All joints must be carefully smoothed - this way you will protect the wall from the appearance of depressions or bumps on it.
- At the end of the work done, walk with a damp brush or sponge over the entire treated area.
Corner repairs are carried out as follows:
- First, prepare the gypsum mixture.
- Clean the corner of the old plaster, scrape out the seams and moisten the surface with water.
- Then cover one side of the corner with fresh solution and wait until the composition hardens.
- After this, a wet board is applied to the surface, which should lie flush with the old coating layer.
- The next step is to moisten the second side of the corner and plaster it in the same way.
- The boundaries between the old and new solutions are blurred.
Restoration of Venetian plaster
The process of repairing this type of coating will require a little more time and effort. this work consists of several stages:
- First of all, the damaged layer of plaster is removed from the wall and the surface is cleaned.
- After this, prepare a solution of PVA glue. Add 5 parts water to 1 part glue and mix the mixture thoroughly until smooth.
- The wall to be treated is covered with the resulting mixture, covering areas around the damaged area.
- Then apply a base layer of plaster and wait for it to dry.
- After that, the surface area is covered finishing layer plaster that performs a decorative function.
- The next step is to give the decorative coating the same texture as the rest of the wall. To do this, use sponges and special spatulas. The work should be carried out in such a way that no boundaries between the old and new cladding are visible.
- After a few days, when the restored area is completely dry, it can be painted in the desired color.
Grinding plaster
In order for your plaster to last as long as possible without repair, it must be periodically updated. Over time, any plastered surface begins to become covered with small cracks. Before things go too far, you can grind the top layer of coating. This process is carried out as follows:
- Old wallpaper is removed from the wall. If the paper adheres too firmly to the surface, soak it and scrape it off suitable tool. Remains of paste or wallpaper glue are also washed off with warm water.
- Do the same with paint, scraping it off the wall with a spatula. You need to work with the tool carefully, trying not to leave deep scratches on the coating, otherwise they will have to be covered with putty later. If the paint is water-soluble, you can simply wash it off.
- The grinding process is carried out in zones. Select an area of approximately 0.5 m² on the wall and moisten it a little.
- Then, using a special trowel, the surface is covered with a thin layer of plaster. The distance between individual strokes should be about 10 cm.
- After this, the treated area is thoroughly rubbed with circular movements of the tool.
- If small defects remain on the wall, they are covered again with a small amount of solution.
Sealing cracks
If there are quite noticeable cracks on the surface of the wall, they are covered separately. To do this, the gaps are slightly deepened and the crumbling edges are cut off. After this, the defects are sealed with plaster. When it dries, the wall is rubbed down.
If cracks form at joints reinforced concrete floors, they are covered with a solution based on fine sand. After this, the surface is carefully leveled and rubbed.
The process of applying plaster to the wall can be seen in the following video:
The article describes the reasons for the formation of cracks in plaster on the wall, swelling of the surface, and its delamination. It also describes in detail how to repair a wall with cracks, and how to prevent a plastered wall from immediately cracking.
Causes of cracks
Blistering can occur due to incorrect composition of the solution. If unseasoned lime was used, in which there were unslaked particles, then after covering the walls, small swellings may appear on them. After some time, the coating will completely deteriorate. To prevent this from happening, you need to clean off the plaster with bubbles, and then spread more on the surface. high-quality composition. Other reasons:
- Cracks may appear when using poorly mixed or greasy solutions. Fatty solutions are those in which there is an excess of astringents.
- Cracks also occur due to surfaces drying out too quickly. To prevent this from happening, you need to prepare the plaster strictly according to the instructions, carefully stirring the composition before applying it to the walls.
- It may come off the wall due to excessive moisture on the wall or an overly dry surface.
- It is also advised to wait until each applied layer dries, and finishing Apply to a completely dry wall.
- On new wall in a built-in building, it is worth using concrete contact before each new layer of plaster, this will ensure adhesiveness, which is absent without preliminary surface treatment.
- You should not plaster walls in an unheated room before frost.
Why do walls crack after plastering?
If you cover a wall with a plaster composition without following the technology, it will definitely crack:
- Aerated concrete is vapor permeable, which is why the plaster applied to aerated concrete must also be vapor permeable. It is even better if it has stronger vapor permeability than aerated concrete, otherwise steam will accumulate in the coating and it will crack.
- You also need to remember that finishing must be done in one day. Otherwise, the next day there will be a different air temperature and humidity, they will change the conditions for the mixture to solidify, and the wall will crack.
- If moisture gets on and under the plaster during work, it may crack.
What to do?
If the cement-based coating has come off from the aerated concrete, then it needs to be completely cleaned off and reapplied.
First, it is advised to finish the walls inside the room, and only then finish the facade.
The plaster may come off due to constant changes in humidity. You need to find the source of the increase or decrease in humidity and correct it.
If this happened due to a mixture of poor quality or an old composition, then you can only completely remove the old finish and apply a new one.
The problem should be carefully studied; perhaps this was due to subsidence, which appeared due to the fact that the plaster preparation time specified by the manufacturer was not followed. Then just redo everything.
When applying the mixture in hot weather, it is necessary to slow down the drying of the walls. To do this, they are moistened from time to time.
But if cracks do occur, then the walls are rubbed with mortar or gypsum dough. If the gaps are too large, they are widened, cleaned, moistened and plaster is applied.
Try placing paper tape over the peeling plaster area. If the tape breaks, you will have to start all over again.
Sealing cracks in plaster has its own algorithm of actions, filled with some subtleties that require careful study.
Subtleties of sealing cracks:
- It is advised to buy a mixture of the same brand that was used previously.
- You cannot work at air temperatures below +5°C and at humidity levels above 80%.
What to do if the wall cracks again?
- Cement must be carefully but thoroughly cleaned using a hammer and chisel. Any area that looks unsafe should be cleaned.
- Then thoroughly rinse the crack to remove any remaining material, dirt, or dust. Wait until everything is completely dry. At the same time, you can prepare the solution. Before application, the crack should be moistened from the inside and covered with a new solution.
- Next, attach the reinforced paper tape and wait and see what happens.
- Then you can plaster the tape. Afterwards it should be sanded and then finished.
- A crack that is less than 5 mm wide, before applying finishing putty covered with assembly glue.
How to repair cracks in the wall if the cause has been eliminated, but many small cracks remain on the surface?
First you need to seal every crack, and then attach reinforced mesh. Sealants can be used, but the sealant must have such properties that it can be applied to a lime wall.
If the wall is made of concrete, then initially you need to lubricate the crack inside with PVA glue, and then cover it with a cement mixture.
Why does plaster fall off the wall after renovation?
The plaster falls off the wall after repair due to non-compliance with plastering technology.
Make the mixture strictly according to the instructions, knead it correctly. If you did everything correctly, then you will need 9 kg of gypsum-based composition or 20 kg of sand-cement composition per 1 cm layer with an area of 1 m². It is required to stir the composition in clean buckets and use clean tools.
How to properly prepare a mixture of gypsum and cement?
- If you are making a gypsum composition, then the entire composition is slowly poured from the bag into cold water, wait a short time, and then mix again. Do not mix old and new formulations.
- If you pour a lot of water into the sand-cement mixture, it will eventually shrink a lot, which will lead to cracks on the wall.
If the wall swells at the site of the crack
It may still peel off. This occurs because the solution was applied to an overly dry surface. Or this solution was applied to another solution having lower strength. To correct the situation, you should clean off the peeling plaster, wet the wall and apply plaster on it again.
Do not forget that before work you should carefully examine the wall and understand where else the material may peel off. When creating a solution and spreading it on the wall, do not forget that the strength of the solution should vary in decreasing order. That is, the first layer of plaster should be stronger than the rest.
Swelling also occurs due to plaster covering an excessively damp wall. To correct the situation, you should clean off the material, dry the surface and apply the solution again.
You need to follow these tips and recommendations when puttingtying walls:
- Before applying putty, you should wet the wall plain water. This can be done with a spray bottle.
- The temperature in the apartment should be less than +24°C, but more than +5°C.
- It is impossible for direct rays of the sun to fall on the wall and for there to be a draft.
- A solution with a layer of more than 2 cm must be secured using beacons.
- Before applying the next layer, you should carefully inspect the previous layer to ensure there are no cracks on the wall.
- Gypsum-based plaster is applied in a layer less than 1.5 cm, and cement-based plaster is applied in a layer less than 2 cm.
- We must not forget that on surfaces made of brick, concrete, stone, plaster is applied in a layer of less than 0.5 cm, and on wood - less than 0.9 cm.
- You need to read the instructions written on the bag of dry plaster.
- The components should be mixed in a certain order.
- The walls are reinforced.
To prevent cracks from appearing on the walls later, you must strictly follow the instructions. Avoid drafts and direct sunlight into the room.
If cracks do appear, they need to be cleaned and the walls puttyed again.
Useful video
Repairing 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.
If cracks are clearly visible on the surface of plastered walls, then delamination is not easy to notice. In certain areas, swelling appears, 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 complete removal of the previous layer. It is carried out on 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 construction beacons must be installed.
In cases where the area of the damaged surface is quite small, the edges of the previous coating act as beacons.
Before you begin surface restoration work, you need to identify all existing defects.
To do this, during the preparation process, all detected cracks are opened using a spatula, and with its handle it is necessary to tap all suspicious places.
Where the sound is dull or there is noticeable swelling of the old one, beat off the damaged layer with a hammer and remove it with a spatula, exposing the masonry.
When repairing old plaster in large areas, it is necessary to perform reinforcement using a chain-link mesh for this purpose, which is attached to the wall using self-tapping screws or special mushrooms.
Reinforcement
The solution must penetrate under the mesh Rub the surface with a wooden or plastic grater in a circular motion, after wetting the tool with water.
Each room or apartment requires a careful, economic attitude. It is important to whitewash the ceiling, floor, frames on time. Repair work medium weight easy to do with your own hands.
How to seal plaster?
First of all, determine whether the plaster is firmly attached to the base. This can be determined by tapping the walls or ceiling with a hammer. If a dull sound is heard during tapping, it means that the adhesion strength of the plaster to the base is insufficient. In marked places better plaster beat off.
Plaster defects are removed or repaired as follows:
1. Clean the surface from which the old plaster has been knocked off, or the area from which the plaster has fallen off, thoroughly with a scraper, lightly moistening it with water to avoid excessive dust and contamination of the room.
2. Apply pre-prepared plaster mortar. The solution is being prepared different composition depending on the surface on which it will be applied (composition of solutions for plastering walls - see below).
Mix the indicated materials thoroughly with water until a creamy mass is obtained. It is best to apply the solution manually using a wooden device called a “falcon” and a metal spatula – a “trowel” or an ordinary children’s spatula with a flat surface. The solution is placed on the “falcon” and sprayed onto the wall with a “trowel”.
3. After spraying the solution onto the wall, level it evenly over the entire surface to be repaired with a special wooden trowel. Move the grater from bottom to top, then zigzag your hand left and right. This helps to distribute the solution evenly over the surface so that it is more effective fix loose plaster.
Composition of mortar for plastering walls
The following compositions are used for stone surfaces:
1) mix from 1.25 parts by weight to 1 part by weight of lime and 3 parts by weight of sand;
2) 1 part by weight of lime, 0.4 parts by weight of clay and 5 parts by weight of sand;
3) 1 part by weight of clay, 3 parts by weight of sand and 0.5 parts by weight of fibrous additives (any highly crushed rags).
For plaster concrete surface take a solution of the following composition:
1) 1 part by weight of cement, 4 parts by weight of sand, 0.2-0.3 parts by weight of lime;
2) 1 part by weight of cement, 1 part by weight of lime and 6 parts by weight of sand.
For wooden surface mix:
1) 1 part by weight of lime and 2 parts by weight of sand or 1 part by weight of lime and 2.5 parts of sand;
2) 1 part by weight lime, 3 parts by weight clay, 3 parts by weight sand and 3 parts by weight fiber additives.
Tools for repairing cracks in plaster
The plaster is crumbling, what should I do? It happens that, saving on cement, builders make plaster almost from sand. And such material is used indoors and for exterior finishing walls of any building.
Plaster increases the strength of the wall by almost 30 percent, which is very important, and only then the owners decide for themselves: to paint the walls, tile them or glue them with wallpaper. In addition, such a coating helps to level walls, hide defects on them and ideally prepare surfaces for applying liquid or gluing regular wallpaper.
The plaster may crumble due to high humidity indoors, if the technology was violated during its application or a low-quality solution was used. To ensure that the plaster holds firmly, it is better to entrust the work to an experienced craftsman.
If the walls of the home are plastered with old cement-sand mortar(see Let's look at how to plaster with cement-sand mortar), which begins to crumble at the touch of a spatula, or you are not sure whether it is possible to putty on the old coating without damaging the mortar, the plaster should:
- Strengthen. This method is used if the coating is just crumbling. In this case, it is enough before starting putty to old plaster apply a deep penetration primer or treat the wall surface with concrete contact, which should fix the surface well in cases where the primer cannot handle it.
- 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 when applying it or from incorrect temperature regime when the room temperature is very low.
To do this you need:
- tear off all the old plaster (see How to remove old plaster from walls without problems);
- treat the walls with a primer;
- putty everything again.
After this, you can apply the finishing coat. In this case, the price of the work will be higher, but the result will be better and more reliable.
Which method to choose is up to everyone to decide for themselves; the main thing is to determine when the plaster becomes unusable. Plaster, in principle, should not have high strength - it’s just finishing material, and not a load-bearing element of the building.
How to repair plaster
Advice: If you are not confident in your own abilities or 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 wall surface from moisture you will need to apply protective composition, and then proceed to further operations.
The repair procedure is as follows:
- The wall is carefully and carefully scraped with a metal brush to remove all remnants of the old plaster.
- A special primer mixture is applied in two layers.
- Any stains remaining after the primer has dried are lightly washed off with a stream of water.
- The wall dries for about three hours.
Advice: If the coating defects are very serious, the damaged areas should be re-applied with a putty mixture or plastered.
- The applied coating should be about three centimeters thick.
- When plastering a wall, the powder is dissolved in water and applied in a small layer.
- The first layer is performed to level the wall (see Leveling walls with plaster according to all the rules).
- After one hour, a second layer is applied superficially.
How to strengthen plaster
To work you will need:
- Primer.
- PVA glue.
- Wallpaper glue.
Instructions for strengthening cracked, peeling or crumbling plaster:
- To avoid such defects, the plastered surface must be strengthened with a primer. This coating is an important condition for execution finishing and repair works good quality. It is used to finish the surface of walls and ceilings before applying paint, wallpapering and tiling. A primer is a mixture of a solvent, a binder component and various additives that determine its properties. The dried material creates an opaque film of one thickness, increasing the adhesion or adhesion of subsequent layers of coating.
- According to their purpose, primers are divided into:
- metal surfaces;
- wooden surfaces;
- universal, having acrylic base. Acrylics are used for concrete, cement and gypsum plaster, wood and fiberglass wallpaper. Such compositions dry quickly and do not have a pungent odor.
- The impregnating composition is applied with a roller, in one layer or with a wide paint brush.
- When finishing rooms with high humidity: bathrooms, showers, use special compounds, they create a layer of waterproofing. For example, Aura Primer is suitable for dry rooms and high humidity. The mixture is diluted with water immediately before use in a ratio of 1:4. The degree of dilution can be reduced to 1:6, this will increase protection against moisture.
- Strengthening plaster can be done cheaper wallpaper glue. This method is often used before wallpapering. At high-quality glue, the adhesion is strong, the wallpaper and putty will not come off. But this option does not apply to heavy vinyl wallpaper.
- An unjustified saving is the use of PVA glue for primer, especially in rooms where high humidity. The adhesive contains dry components; they are capable of absorbing moisture, which after painting can contribute to the appearance of matte spots due to uneven paint absorption.
How plaster is strengthened with impregnations
Today, manufacturers produce high-quality “strengthening” impregnations in plastic containers. Before use, the liquid is poured into a convenient container, then 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, and bind even microscopic particles together.
After strengthening the plaster with impregnations, cracks will not form and the coating will no longer crumble. Using this method with your own hands to strengthen the surface is quite simple.
In addition to using special impregnating compounds, the plaster can be strengthened using a reinforcing mesh, and then putty can be applied. The option for strengthening the plaster is selected depending on the situation and goals.
How to strengthen plaster with reinforcing mesh
In more difficult cases Reinforcing mesh is used to strengthen plaster. In this case plaster layer very badly damaged, as can be seen in the photo.
Tip: To strengthen the plaster, you must use a metal mesh, preferably stainless steel. Once it rusts, traces of rust may show through the thick coating, resulting in additional rust control costs.
With this method:
- The mesh is attached to the wall in any way: with dowels or nails, which depends on the material of the wall.
- A new layer of coating is applied on top, not in too large a layer. The main thing is that the mesh is closed.
The video in this article shows details of strengthening the plaster.