Do-it-yourself plaster ceiling repair

In detail: do-it-yourself ceiling plaster repair from a real master for the site my.housecope.com.

Any repair begins with a rough finish of all surfaces. First of all, the ceiling is prepared and this process should be given enough time and effort, since it can be quite difficult to create a perfectly flat surface the first time.

Today we will find out how do-it-yourself ceiling plastering is carried out, how to mask or fix small flaws on the surface after its preparation, how to cheaply repair the ceiling after damage, and what preparation requirements are needed for certain finishing materials.

Before starting the repair process, you should study some of the features of leveling ceilings. At the moment, there are such ways to align it:

Dry method - is not used so often, but allows you to create a perfectly even base in the shortest possible time. Drywall is used as a consumable material, the joints of which are subsequently puttied. This investment cannot be called minimal and, unfortunately, it is not suitable for all dwellings. Plasterboard sheets are used in the case of running ceilings
Wet option - ideal when you need to cover small defects or prepare the ceiling for painting. For surfaces with differences exceeding 4-5 cm, it is necessary to use plaster, and for irregularities of 4-5 mm, putty is used. An uneven ceiling does not stand out for its attractiveness, and when the height differences on it are more than 5 cm, a stretch ceiling or gypsum plasterboard should be chosen as a design.

Important! When applying a thick layer of plaster, the coating may begin to crack, crumble or fall off in pieces, which threatens not only to damage the repair, but even to injury. If you notice cracks on the plastered ceiling, you should not wait for it to collapse - dismantle it.

Video (click to play).

Before you start using a plaster mortar, you need to find out all its pros and cons, and then clarify how to properly prepare the mixture with your own hands. There are a large number of recipes and proportions among home craftsmen, but today we will look at the preparation standards and the benefits of such plasters.

Plaster for the ceiling is selected not only according to price preferences, but also according to the declared characteristics of the material. High-quality plasters are sold in hardware stores and have quality certificates.

What kind of plaster for the ceiling of the house to choose and how much does it cost? - a question that worries any beginner in terms of repair work. Among the variety of finishing mixtures, the main ones can be distinguished:

Ready based on polymers - the preparation of the ceiling with their help is carried out at the highest level. The advantage lies in the ease of use of the solution, which does not need to be diluted. However, this is an expensive choice with large flaws in the ceiling - at the stage of full-scale leveling, ready-made mixtures are unprofitable.
Cement - soundproof, act as a heater, to improve the quality, you can add lime and sand. Lime and sand plasters do not shrink
Gypsum - gypsum has good adhesion to concrete surfaces. They are easier to work with, they are distinguished by an average pricing policy. Plaster perfectly lays down on concrete and brick walls.

ceiling plastering process

Before you start plastering the ceiling, let's look at the popular and sought-after manufacturers of putty mixtures:

Important! Photo and video lessons teach beginners how to level the ceiling with plaster on their own, how to calculate the right amount of the mixture, how to make an estimate for further work, what proportions to use when making plaster and how to hide a small flaw by creating a pattern on the ceiling with putty.

Sometimes it is simply impossible to carry out repair processes with your own hands due to a number of reasons. Then qualified specialists who will need to pay for their services can come to the rescue. Let's find out what prices for plaster ceilings per m2. A small table shows prices for certain processes:

Repair of any premises (residential or office) always begins with the finishing of the ceiling. There are different ways to do this, but whichever one you choose, painting or wallpapering, etc., first of all, you need to do the preparatory work. And the most time-consuming of them is do-it-yourself ceiling alignment.

Three types of metal spatulas of different sizes, with a rubberized handle.
Capacity for 15-20 liters, with high sides and straight walls. High sides will protect against excessive splashing, while mixing, and straight walls will make it possible to pick up the solution with a spatula without residue.
Mixer for preparation of working solution.
Paint brush and roller for applying primer.
Construction sanding for final polishing of the ceiling surface for painting.

Before proceeding with the ceiling leveling procedure, it is necessary to prepare the surface by cleaning it of old paint, whitewash or other coating. And the more carefully this is done, the better the subsequent finishing operations will be performed. The surface is usually cleaned with a special scraper or spatula. You can also clean dry paint. But much faster and with less effort, you can do this work if you moisten the surface of the ceiling with plenty of water and arrange a draft in the room. The old coating will begin to bubble from this and it will not be difficult to remove it. After removing it, the ceiling must be thoroughly washed.

The next step is to decide on the alignment method. The choice of material for the primer depends on this. They differ in purpose:

under water-based paint,
under putty or plaster,
suitable for all types - universal.

Plastering the ceiling is a highly labor-intensive process. And although there are many different methods for eliminating irregularities in the ceiling, leveling the ceiling with plaster is still relevant. And if the level difference approaches the 5 centimeter mark, then this is the only possible solution in obtaining a quality repair.

You can plaster any surface: concrete and wood, columns, beams and other structures made of steel. Before applying plaster to the ceiling, preparatory work should be carried out.

The concrete ceiling must be well cleaned of various contaminants. Particular attention should be paid to mold or other stains of fungal origin, which must be treated with a special disinfectant solution. For example, copper sulphate, German-made Pufas or Homeenpoiste, the Finnish company Tikkurila. If on a concrete floor, the fungus has occupied large areas, it is fought with open fire (blowtorches, plasma welding, etc.). If the ceilings have already been painted or whitewashed, the old coating should be removed.
Apply a primer with a reinforcing composition, and then with a special primer mixture "Betonokontakt".
For better adhesion of primers to the concrete surface, it should be treated with a sandblaster that creates roughness. For the same purpose, it can be slightly notched or cut.
On wooden ceilings, as well as on the surface of structures made of steel, before applying the plaster, a metal mesh is stretched, with a mesh size of 10x10 mm. It is attached to the surface to be treated, including joints and seams, with special nails, with a wide head, or staples.

Plastering work is usually carried out on lighthouses, the installation of which is the most crucial moment. If they are installed correctly, you will end up with a perfectly smooth plastered surface. Therefore, it is important that the entire technology of plastering the ceiling on beacons is observed.

It is necessary to start this work with leveling the room. On the walls it is necessary to mark the zero mark. For this, a paint cord is used.
The location of the point that is the lowest on the ceiling is determined. This is the place where the first beacon was installed.
Under the beacons, every 300 mm, gypsum marks are applied in small molds over the entire surface, on which they will be installed. This should be done in such a way that there are as few connections as possible, since it is in them that errors are most often made.
It is not recommended to lay a layer of plaster on the ceiling more than 5 cm. Therefore, the height of the beacons should not exceed this value. To control them in a horizontal plane, a two-meter level is required. It is carried out after the installation of all beacons is completed.

When you are done with the installation of beacons, you can start finishing the ceiling with plaster using the following technology:

If the difference in the level of the ceiling is less than 5 cm, you can level the ceilings with dry mixes. It is advisable to use them for small amounts of work, in particular for filling potholes, when buying a large amount of other materials is not financially profitable. Rotband (made in Germany) is considered the best of them - a universal mixture for plastering, on a gypsum basis.

After completing the “rough” leveling with plaster, you can proceed to the final leveling with putty.

For processing ceiling without significant differences in ceilings, it is best to use leveling the ceiling with putty. Putty differs from plaster in the size of the filler. She has a small, not exceeding 1000 microns. Therefore, it is most suitable for removing small defects on wood and other surfaces, such as cracks and other irregularities. This achieves perfect smoothness.

The putty is applied in a very thin layer. Before applying putty, all layers of old plaster (if any) are removed from the ceiling to the base. Small irregularities, as well as any tubercles, are cleaned with a construction sandpaper or a hinged grater, on a long handle. Then, a paint grid can be attached to the surface to be trimmed using PVA glue or a special compound. It is often called sickle because of its similarity to gauze. Recently, on sale you can buy a self-adhesive serpyanka.

Having completed the preparatory stage, it is necessary to prepare a solution for putty. To do this, 30 kg of dry putty mixture is poured with 12 liters of water and quickly mixed. It is best to use a construction mixer equipped with a large whisk or a drill with a special mixer for this. When finished, the consistency of the mixture should resemble thick sour cream.

All further work must be done promptly, as the prepared solution very quickly begins to set and harden. This is done as follows: using a narrow spatula, the solution is applied to a spatula with a wide blade. Then it is transferred to the surface of the ceiling and pressed tightly against it. Do not waste time on leveling emerging divorces. They are easily removed after hardening with a grout mesh.As soon as the last applied layer of putty dries, the entire surface must be sanded. For this, a special grout with a mesh is used, the minimum coarseness of which is 120 units.

In order for the work performed to be of high quality and to please you with the beauty of a flat and smooth surface, it is better to purchase all materials (primer, putty and paint) from one manufacturer.

So, do-it-yourself ceiling puttying can be divided into the following stages:

Preparatory, during which the concrete floor is cleaned, which consists in removing all irregularities that are higher than two mm. For this, a puncher equipped with a special nozzle is used.
Ceiling primer with a composition that has deep penetrating properties. It is performed with a paint brush or roller.
Performing a starting putty as a leveling layer. To do this, it is applied to the surface of the ceiling, with a layer of 1 cm. By consistency, the finished putty solution should be like thick sour cream. To obtain a flat surface, a metal semiter is used.
The final stage is the finishing putty of the ceiling. It is recommended to apply it in two layers. If the temperature in the room is above 18º C and it is well ventilated, then it can be done four hours after applying the starting putty. Under other conditions, the drying of the previous layer may be delayed and the transition to the final stage will have to be postponed the next day.
If the conditions necessary for the quick hardening of the putty layer are met in the room, then the very next day, you can start grinding the surface. It is advisable to use a vibration grinder for this.

Whatever method of leveling the ceiling you choose, do not forget that for painting, on the leveled surface, you must apply a primer layer, which can be used as the same paint that will be used for the main painting.

Take two spatulas - one with a wide canvas (in your left hand). A ready-made solution is applied to it. In the right hand is a working spatula.

The mixture should be taken little by little, trying to distribute it in the center of the blade of the working spatula. It should be applied as follows, so that it lies completely on the surface of the ceiling.

It is necessary to move in such a way that the surface is even and smooth, it is impossible to return and redo already finished sections.

So that there are no stripes on them, the working spatula must be held at a slight angle to the surface of the ceiling. This will allow its middle part to level the putty on the surface. This will move one edge over the rough surface, while the other (the one that moved over the already treated area) will be in the air, which will provide a smooth surface without streaks and scratches.

The quality of the puttying work depends largely on the correct choice of spatula. Its canvas should be of medium hardness, since excessive softness causes excessive deflection of the spatula, while its side edges turn forward. As a result, stripes remain. Therefore, a standard spatula needs to be slightly modified by turning the sharpness of the corners with a file. In this case, the end of the blade will acquire some ovality. This will ensure convenience and safety in work, and the finished surface will be of excellent quality.

How to repair a ceiling? This question is often asked by the owners of houses and apartments who are planning to make repairs in the premises on their own. There are a lot of finishing methods, so choosing the right option is difficult. The problem of finishing the ceiling can be solved by installing a suspended structure or installing a stretch ceiling. If you do not want the ceiling height to become smaller, it is best to give preference to traditional technologies.

Of course, today plastering is not chosen as often as it used to be, and there are several reasons for this.

Finishing the ceiling is a rather complicated process. A person who has no experience in the construction industry and has not been trained is unable to do a quality job. But even a novice builder can carry out the installation of a plasterboard ceiling, although the quality of the installation remains in doubt.

Plastering the ceiling is one of the jobs that can be called dirty. Masters when finishing use liquid solutions. When applied to a surface, splashes can stain clothes, hands and face. The solution often gets on the floor and walls.

In some houses the ceilings are very uneven. If the height difference is large, then be prepared for high costs for leveling materials.

You can do all the work on your own, but in the absence of skills, you cannot do without the help of specialists.

Types of irregularities in the ceilingCeiling plastering is a repair process consisting of a number of stages. If you do not want to be disappointed as a result of plaster work, then you must take into account all the nuances. Preparation is very important, and the plastering process itself must be carried out in strict accordance with the technology.Start by taking a close look at the ceiling. You must choose the best repair method, taking into account the recommendations of specialists. Pay attention to the following points.

If the ceiling is uneven, the height difference at its different points is more than 5 mm, then it is better to choose not plaster, but putty. The fact is that plastering such a surface will require large financial costs.

With a more significant height difference, for example, when the difference between two points reaches 5 cm, you should not choose plastering. The easiest way is to opt for a tensile structure or mount a suspended ceiling.

If you study the ceilings in the rooms, most often a small difference is recorded. It makes sense to use plaster if it is from 2 to 5 cm. Remember that plastering is a rather complicated process. By increasing the thickness of the layer, you will have to spend more time and effort on the job.The easiest way to make repairs is if you bought a room in a newly built house. You can plaster a reinforced concrete slab in a new building in a short period of time. But most often there are situations when it is necessary to repair the ceiling after numerous paintings.We make notches on the ceilingThe work is complicated by the fact that in most cases you have to deal with mold and large drops. In addition, to form an even ceiling, it is necessary to remove deep cracks that can often be observed between the plates. It is impossible to make the ceiling even if you see that the old plaster has chipped or crumbled. All the shortcomings listed above must be eliminated, only after that it makes sense to start repair work.Table. Removal of old plaster.Repair of any premises, whether residential or office, begins with the ceiling. Regardless of what kind of finish is provided for by the design project: whitewashing, painting or pasting with decorative panels, the surface to be treated must be prepared in accordance with all the rules.Do-it-yourself ceiling plasteringComparing the various methods of leveling the ceiling, you should find out what is the fundamental difference between plaster and putty? Both options for eliminating nervousness refer to the “wet” method, which is based on the use of various building mixtures and compositions. The “dry” is considered to be the alignment of the ceiling with plasterboard sheets, but they resort to such a cardinal solution to the problem as a last resort.Surface puttying is performed as a finish before painting or wallpapering.The layer of material cannot exceed 3-4 mm. The peculiarity of such a coating is that its use is permissible on almost even surfaces with minor defects, inconspicuous cracks and small irregularities, since a finely dispersed putty mixture is not able to tighten and hide more significant problems.Stucco screed is made on surfaces with height differences up to 45-50 mm. Thanks to coarse particles, the mixture easily copes with deep cracks and seams between slabs and ceilings. However, if the differences exceed 5 cm, it is not recommended to use plaster mixes - too thick a layer of material is not only aesthetically unattractive, but also dangerous due to the likelihood of cracking and peeling of the plaster from the ceiling, which can be a potential health hazard and lead to injury. In such situations, the best solution would be to install framed ceiling structures using plasterboard slabs or stretch ceilings made of modern materials.Pros and cons of plasterWhen choosing one or another method of finishing, you should take into account all the advantages and disadvantages of the material.The advantages of plaster are in the following aspects:

it is a completely safe and environmentally friendly material that provides a durable and long-term coating;

self-made work will be less expensive than installing a suspended or stretch ceiling;

The “naturalness” of the material makes it possible to use it for decorating the homes of people suffering from respiratory diseases and various allergies;

surface treatment with plaster will slightly reduce the height of the room.

The disadvantages of plaster mixes are as follows:

there is a restriction on the maximum thickness of the plaster layer - experts do not recommend exceeding a threshold of 5 cm - with large differences, it is not advisable to level with this material and is characterized by a large consumption of the mixture;

if it is not possible to do the work yourself, the services of professionals will cost a significant amount, plus consider the cost of the material itself;

leveling the ceiling with plaster mixtures requires certain skills in working with materials and tools, and the process itself can take a very long time, since the main task is to make the surface smooth and even.

To plaster the ceiling on your own, you will need the following materials:

square containers of large capacity (from 15 to 19 liters). It is recommended to choose a container with high sides to prevent splashing during mixing and straight walls for a better set of mixture on the tool;

metal and rubber spatulas of different sizes. For ease of use, preference should be given to a tool with rubberized handles;

construction trowel;

rule;

paint brush;

roller and cuvette for primer;

building level;

sandpaper of various grain sizes to eliminate coating defects at the initial stage of processing and final grinding, holder;

a drill with an appropriate nozzle or a construction mixer;

sickle;

stable ladder;

personal protective equipment (rubber seals, plastic mask and respirator).

Tools, fixtures, equipment for plastering

The preparatory stage is of great importance even if it is a new building. Ideally, the ceiling should be cleared down to a concrete slab.

Traces of mold, fungus and rust smudges should be removed with a wet sponge, and then wash the ceiling area with special compounds. The old and peeling layer of plaster and other building materials must be removed.

Traces of mold, fungus and rust smudges should be removed with a wet sponge.

Even if the coating looks durable and without noticeable signs of wear, experts recommend removing it. Firstly, sooner or later cracks may form on the ceiling, and secondly, such layering will steal extra centimeters of space.

The most suitable tool for the work is a narrow spatula. If the layer of finishing materials is difficult to remove, you can try to “beat” the treated area with a rubber hammer or use an electromechanical drill with a special brush attachment. It is very important not to forget to protect your eyes, head and respiratory tract from construction dust.

It is useless to blur the plaster with various solutions, since after such treatment a thin, smooth and difficult-to-remove layer remains on the ceiling surface, which will prevent high-quality work due to low adhesion, which can cause peeling and cracks in the applied plaster layer.

Cracks and ceiling seams are recommended to be embroidered. The surface freed from the layers of the old coating should be worked out with P80 coarse-grained sandpaper to remove bumps and remaining pieces of plaster. In addition, sandpaper is the best way to prepare the ceiling for priming.

Do-it-yourself ceiling priming

When choosing a primer, preference should be given to solutions for smooth surfaces. They contain small granules in their composition, after drying they form “roughness” on the surface, which contributes to the best adhesion of the plaster layer to the primed concrete slab, and the antiseptic substances that make up the solution prevent the development of foreign microflora.

The primer layer must be thoroughly dried before the subsequent stages, on average it takes at least 12 hours.

Plaster mixtures are presented in two versions: ready-made and dry. There are no differences in consumer properties between them, but the price differs several times. Although it is not difficult to prepare the mixture yourself:

the amount of water recommended by the manufacturer is poured into the prepared container;
the dry mixture is gradually poured;
with a construction mixer, the solution is mixed until homogeneous and left with the lid closed for 15-25 minutes, after which the mixers are re-mixed.

Plaster is recommended to be applied with a plastic or rubber spatula, but leveling is more effective with a metal tool. Each layer of plaster dries for at least 16 hours in the absence of temperature fluctuations and drafts.

Ceiling irregularity detection

Depending on the material of the ceiling and its curvature, there are several technologies for performing plastering work.

Applying plaster to the ceiling

The ceiling is plastered with two, less often three layers of the mixture. If there are minimal surface defects, it is allowed to apply plaster on selective areas, followed by leveling the material, but the craftsmen recommend applying at least one solid layer to the entire surface. If the irregularities are numerous and the estimated layer of plaster will exceed 10 mm, before starting work on the ceiling, you need to fix the paint grid - this will protect the coating from cracks and give greater strength.

Proper plaster ceiling

If the surface differences are significant and are more than 2 cm, then it is better to level with the help of beacons. Their installation is a responsible and important stage.

With the help of a laser level, leveling is performed and the "zero" mark is determined. To do this, the lowest corner of the ceiling is determined, and a corresponding mark is made on the wall.

After that, using a paint cord, the lowest point on the ceiling is calculated, from where the installation of beacons on the ceiling will begin.

Lighthouses are mounted parallel to each other on plaster blotches with a distance between rows of 15-20 cm less than the width of the rule.A short rule is easier to work with, while a long one guarantees a better result.

A short rule is easier to work with, while a long rule guarantees a better result.

Once the beacons are installed, you can start plastering. The mixture is distributed between the beacons with a spatula, and its excess is removed by the rule.

All this was told very briefly - in fact, the main stages of the entire process of plastering the ceiling were simply listed. In fact, each of these actions has many nuances that you also need to know about. Therefore, below the attention of readers will be offered a table in which in detail, literally - step by step, the process of plastering the ceiling with the necessary explanations is shown.

Detailed step-by-step illustrated instructions for plastering the ceiling with a gypsum-based mortar

First of all, one remark must be made. To an inexperienced reader, at first it may seem that everything is done quickly and simply enough. In fact, leveling the ceiling with plaster is a very time-consuming finishing operation that requires considerable experience. If the owner of the apartment has never encountered a plastering business before, then he should, as they say, think ten times and evaluate his capabilities before proceeding with the repair.

Despite the fact that the technologies for applying plaster to walls and ceilings are, in principle, very similar, work on a vertical wall surface is much simpler. And in the event that in this regard there are at least some acquired skills, you can try your hand at the ceiling.

Only one question remained unanswered - how much dry mortar will be needed to plaster the ceiling? We hope that the reader will be satisfied with the answer that he will receive using the online calculator below.

The initial values for the calculation will be:

Ceiling area. For a rectangular room, it is not difficult to calculate it.

And what to do in more complex cases?

If the room has some special configuration, then you can apply different approaches to calculating its area. All this is detailed, with the application of convenient calculators, in a special publication of our portal How to calculate the area of a room

The planned minimum thickness of the plaster layer depends only on the specific conditions of the room to be finished and the wishes of the owners. As a rule, a layer less than 5 mm is not applied when plastering.
The amount of difference in the height of the ceiling, which must be eliminated by plastering.
Master's skill level. For a professional, no more than 5% of the solution will go to waste, and for a beginner, at first, 15% of the stock may not be enough.

The resulting value will initially be expressed in kilograms. But dry plaster mixtures are sold in paper bags of 25 or 30 kilograms, and acquiring an open bag is a great stupidity, since no one can already guarantee the quality of the solution. This means that one way or another it will be necessary to round the amount of the purchased composition up to the whole number of bags. This stock will still not be superfluous - all the repairs are yet to come! This is also taken into account by the calculation program.

Ceiling Plaster Mesh

Plaster on a wooden ceiling

Before applying the plaster mixture, a metal mesh is attached to the ceiling, having a cell size of 100x100 mm, or a two-layer shingle is stuffed so that the nail heads do not extend beyond the rails. This is done to avoid cracking and peeling of the plaster, especially if the house has a residential attic or second floor. The plaster is applied in two layers, each of which is carefully leveled with a spatula and dried.

plasterboard ceiling plaster

The process of plastering drywall sheets consists in filling dents and joints with a building mixture.In the case when the gaps between drywall blocks are significant, experts advise using sickle in the necessary areas. However, it should be remembered that the maximum layer thickness on areas not covered by the mesh cannot exceed 15 mm.

A flat ceiling is one of the components of modern renovation. One of the ways to level is plastering the ceiling. The technology is not very complicated, but requires accuracy. With modern materials and tools, this work can be done by hand. This is not to say that it will be easy, but you can cope without the skills of a plasterer.

There are two technologies for plastering the ceiling - with and without beacons. That's right - to do with beacons. Then the surface of the ceiling is obtained in one plane. However, there are ceilings with a very large height difference. Throwing a layer of plaster 5 cm thick on the ceiling is dangerous: it can fall. Even if you make several layers with a primer after each, there is still no guarantee that such a large layer will hold.

Improperly applied plaster can fall off

In general, with a large curvature of the ceilings, it is recommended to align them with plasterboard suspended ceilings, but not all rooms allow you to “steal” about 10 cm in height. In this case, you can do it wrong - plaster the ceiling without beacons.

The whole idea is to make the ceiling smooth in some area. It will not have noticeable differences, it will visually look like it is even. And the fact that in different angles the distance to the floor will differ by several centimeters cannot be determined “by eye”. With this technology, the main task is to make the junction of the ceiling and walls smooth. This line is very clearly traced and should be straight. If you choose this ceiling plastering technology, you need to start plastering from the walls, towards the center.

For plastering the ceiling, you can use a regular cement-sand mortar, or the same, but with the addition of lime. But it is desirable to apply a small layer at the same time. Although such a mixture turns out to be the cheapest, recently it has been used infrequently - it may fall or crack.The place of the usual solution was taken by polymer-based plasters, which have better adhesion, less often cracks. Their disadvantage is the high price. But redoing the ceiling after the applied layer has fallen will not be cheaper. Therefore, they prefer to immediately make a stream plaster from modern mixtures. Some types of similar materials recommended for ceilings are shown in the table.If the experience of plastering work is small, when choosing a composition, pay attention to the time before the hardened solution hardens. During this period, it is necessary to apply and level the entire solution, because then it begins to harden, loses elasticity. Of the plasters listed in the table, Volma has the longest "life". But not everyone likes to work with her, many say that it is easier with Knauf, although they have a shorter curing time - 50-60 minutes, but it is more than enough even in the absence of experience.Normal ceiling plastering without a thorough primer will not work. It improves the adhesion (cohesion) of the plaster mixture with the base. Basically all the problems with the falling and peeling finish on the ceiling due to the fact that the base was not primed. That's why we don't skip this step. Moreover, if there are several layers of plaster, it is desirable to treat each of them with a primer (with complete drying).First, we prepare the base - we clean it from old coatings, and then we process it with a primer. To do this, pour the composition into a paint bath, take a roller on a long handle (telescopic rod) and distribute the composition over the ceiling. If there are any recesses - recesses, defects on the surface of the ceiling, in which the roller simply does not fit, we pre-treat them with a brush dipped in a primer.Ceiling primer before plasterNow about which primer for the ceiling is better. According to the masters, this is Betonokontakt of the Knauf company.After drying (24 hours), a rough, sticky film remains on the surface. Putty "clings" to it perfectly. Only one point: you need to make sure that while the primer dries, dust does not get on it. Otherwise, the effect of such processing will not be. It can only get worse.When plastering a concrete ceiling from reinforced concrete slabs, the main problem is sealing joints and rustications - recesses at the joints. They are closed up a few days before the general plastering of the ceiling begins - it is necessary that all materials “grab”.First, everything that turns out is removed from the joints. Then, with a brush, everything is cleaned of dust, sand. Prepared joints are coated with a primer. Most often, Betonokontakt is recommended. This treatment significantly reduces the possibility of delamination of the applied plaster layer. If this option is not suitable for some reason, you can use any deep penetration impregnation, but the effect will not be the same.Such seams on the ceiling are not uncommon.After the impregnation has dried (24 hours from the moment of application), a solution is applied. If a layer of more than 30-35 mm is required, it is better to apply it in two layers. Having laid the first one, a relief is formed on it with a notched trowel. A day later, when the solution dries, a second layer is applied. It is already leveled flush with the ceiling.With a large layer of plaster, the joints of the plates are sometimes reinforced with a layer of paint stacks. It is needed so that during seasonal movements of the plates, cracks do not occur at the seam. It is unlikely that someone will nail the mesh to the ceiling, it is usually simply attached to the composition. In this case, after applying the first layer of plaster, a strip of polymer plaster mesh is laid, it is carried out with a notched trowel, deepening it into the solution and, at the same time, forming a relief for applying the second layer.When applying plaster in two layers, a relief is formed on the firstSometimes the rust (crack in the seam) is very deep and there is no way to repair it with mortar. It is also pre-cleaned of crumbling parts and sand, treated with Betonokontakt. After that there are two options:

Seal with mounting foam. We put it a little, about 1/3 of the volume of the gap, after wetting the walls with plenty of water (needed for normal polymerization of the foam). We leave it for a day, after which we cut off the foam so that the plaster fits at least 1 cm into the seam. After that, we prime and apply the plaster in two (possibly three) layers. It is inconvenient to hold a can of foam near the ceiling; you can put a piece of hose on the “nose”. So much easier to workThe question may still arise, how to seal the joints of the plates on the ceiling. One of the polymer-added formulations is usually used, and a good tile adhesive can also be used. It also contains a considerable amount of polymers. They say that after such sealing, the joints do not crack.It looks like a sealed seam on the ceilingIf you have ever plastered walls, you will find it easier. The plaster of the ceiling, although slightly different, is not drastically different. The biggest difficulty is that you have to keep your hands up - they get tired, the neck also gets tired - you have to throw your head back.First, the ceiling is cleaned of all available finishing materials, up to bare concrete. After that, dust is removed from the surface. If there is a construction vacuum cleaner (not household, it will clog), it is convenient to work with it, if not, just remove all dust and sand with a large brush.First, we clean everything to a clean materialIf the ceiling is made of reinforced concrete slabs with large rustications, they are closed up. After the solution dries on the rust, a primer is applied to the clean surface. After 24 hours, work can be continued.The first stage of plastering the ceiling is the installation of beacons, but first it is necessary to determine the maximum and minimum height difference. It is more convenient to do this with a laser plane builder. It is installed under the ceiling, turned on to scan the horizontal plane.They measure at a certain number of points, measure the distance from the ceiling to the luminous beam. In this way, the maximum and minimum deviations are found. The thickness of the plaster layer should be slightly larger than the largest deviation.