What mixtures are needed to level the ceiling? Mixtures for leveling the ceiling. Which is better - gypsum or cement plaster?
For modern renovation before registration ceiling surface it must be made as even as possible. One of the leveling methods is to plaster the ceiling. The technology used is not too complicated, but requires care. You can do this work yourself if you wish.
Methods for leveling ceilings
In practice, one of two technologies is used - plastering the ceiling using beacons and without using them. The first option is considered correct, since then a ceiling surface lying in the same plane is obtained.
But sometimes you can find a ceiling that has a large difference in height. It is dangerous to apply a 5 cm layer of plaster on the surface, as it will most likely fall off. Even if you apply several coats of primer, there is no guarantee that the finish will hold.
In cases where the ceilings have a large curvature, experts advise leveling them by installing suspended ceilings. ceiling structures from plasterboard. True, not in all rooms the height allows you to take 10 centimeters from her. In such a situation, there is no need to doubt whether it is necessary to plaster the ceiling using beacons.
The essence of this technology is that in a certain area the ceiling surface will become smooth. There will not be too noticeable changes on it, it will look even. And the fact that the distance to the floor covering is different angles differs by a couple of centimeters, it is impossible to determine “by eye”.
The main task that should be solved when using this technology is to make the junction of the ceiling and walls as smooth as possible. The resulting line should be straight. When using this option, you need to start plastering in the direction from the walls to the center.
Materials
Before starting repairs, you need to decide how best to plaster the ceiling. You can use standard cement-sand mortar or add lime to it. It is better to apply the plaster in a small layer. This mixture is inexpensive, despite this, it is used in Lately infrequently, as it may fall off or become cracked.
Instead of conventional mortar, it is better to use polymer-based plasters, since they have strong adhesion and are less likely to crack. But these compositions have a drawback - high cost. Many home craftsmen prefer modern mixtures, so as not to have to redo the work later when the applied layer falls off.
When choosing plaster for the ceiling, it doesn’t hurt to use the recommendations of experts:
- When plastering smooth surfaces For ceilings and walls, the Knauf Rotband mixture, which has a white or gray color, has proven itself well. It can be applied in a layer of 5 to 50 millimeters. Polymers are added to this gypsum ceiling plaster.
- To restore old plastered surfaces, including facades, the gray Knauf Sevener plaster-adhesive mixture is suitable. Consists of Portland cement, reinforcing fibers and polymer additives.
- If you plan to use the compositions in rooms with normal humidity levels, you can purchase Bergauf Bau Interier or Volma-Canvas.
If you have insufficient experience in carrying out such work, when deciding which plaster to choose for the ceiling, you should pay attention to the time it takes for the mixed mixture to harden. During this period, it is necessary not only to apply the solution, but also to level it, since then it loses its elasticity.
Of the above-mentioned plaster compositions, Volma-Holst, made from gypsum with biological and mineral additives, has the longest time period for using the mixture. But not all craftsmen like to work with this plaster; they use TM Knauf materials, despite the fact that they harden in 50 - 60 minutes. True, this is quite enough, even if there is no relevant experience.
Application of primer
There is a certain technology on how to properly plaster a ceiling.
A high-quality result will not be achieved without careful application of the primer. It helps improve adhesion between the base and the solution used.
Typically, problems with plaster peeling occur because the surface has not been primed. For this reason, it is better not to skip this stage. If the plaster is applied in several layers, each of them should be treated with a primer, and only if it is completely dry.
First of all, the base is cleaned of old materials and then primed. The composition is poured into a painting tray, a roller with a long handle is taken and the composition is distributed over the ceiling surface. If there are various defects on it in the form of recesses and depressions into which the roller does not fit, they are treated in advance with a brush dipped in the primer mixture.
According to experts, the best primer for the ceiling is Betonokontakt from the Knauf company. A day after its application, it dries, after which a sticky, rough film forms on the surface. The putty adheres much better to this coating.
The main thing is to ensure that dust does not get on the primer while it dries. Otherwise, such processing will not have the desired effect.
Sealing slab joints
The main problem that arises when it is necessary to plaster a ceiling from reinforced concrete slabs, this is the sealing of joints and rustications. The recesses in the places where the slabs join must be eliminated several days before plastering the entire ceiling surface, since the materials must set.
First, everything that is possible is removed from the docking areas. Then the recesses are cleaned of dust and sand. Then the joints are treated with a primer, it is better to use “Betonokontakt”. After its application, the likelihood of peeling off the plaster is reduced several times. As a last resort, you can use another impregnation deep penetration, but the result will not be the same.
When the impregnation dries after a day, begin laying the solution. If it is necessary to obtain a putty thickness of more than 30 - 35 millimeters, it is advisable to apply the mixture in two layers. After laying the first of them, you need to form a relief using a notched trowel. After the solution has dried, which takes about 24 hours, a second layer is laid, which is leveled with the ceiling.
If you have to apply thick layer plasters, slab joints are best reinforced with painting mesh. It will prevent the appearance of cracks in the event of seasonal movements of the slabs. The mesh is not nailed to the ceiling, but attached to the structure. In this case, when the first layer of plaster is applied, a polymer mesh is laid, passed over it with a spatula, deepening it into the mixture and at the same time forming a relief for the next portion of the solution.
It happens that the crack in the seam is too deep and it is impossible to eliminate it in this way. Then it is treated with “Betonokontakt”.
- Sealing polyurethane foam. Its amount should be about 1/3 of the volume of the gap, the walls of which are moistened with water to polymerize the foam. A day later, a primer is applied and plastered in two to three layers.
- The rags are moistened with Betonokontak and hammered into the gap. Leave for 24 hours and plaster over.
To seal the joints of slabs on the ceiling surface, use a composition with polymer additives or high-quality tile adhesive.
Features of applying plaster on beacons
If you have the skills to prepare the surface of the walls, then the job will be easier to cope with. The fact is that plastering walls and ceilings has a lot in common, although there are still differences. The most difficult thing about this is the need to keep your arms raised up. They get tired quickly, as does the neck, because you have to throw your head back.
Preparatory stage
Before plastering the ceiling with your own hands, its surface is cleaned of old materials down to the concrete base. Then remove dust using construction vacuum cleaner. If there is no such device, then they will use big brush so that there is no sand and debris.
If the ceiling is made of reinforced concrete slabs and there are large rusts in it, they need to be repaired. When the solution has dried on them, a primer is applied to the clean base. After a day you can continue working.
Beacon installation process
The first thing they do when plastering the ceiling on beacons is to install them. But first, the minimum and maximum height difference is determined using a special laser device- level. The plane builder is placed under the ceiling and switched to horizontal scanning.
Then the distance from the ceiling surface to the luminous beam is measured at several points. As a result, the maximum and minimum deviation values are determined. The plaster is laid in a layer whose thickness exceeds the largest deviation.
The same operation can be performed using a water level, but it will be much more difficult:
- first, at an arbitrary distance from the floor, a horizontal line is drawn on the walls around the perimeter of the room;
- one end of the level is fixed at this mark;
- with the second, they walk around the room to measure the distance between the water column in the level and the ceiling, thus determining the minimum and maximum points.
After the layer size is determined, beacons are selected - perforated
galvanized slats with protruding backs. They will become the supports for leveling the solution. The height of such a backrest can be 6 and 10 millimeters. You need to select products for which this value exceeds the maximum deviation.
The beacons are set in increments slightly smaller than the length of the rule - a tool for leveling and cutting the mortar. When its length is 1.5 meters, then the planks are placed at intervals of 1.1 - 1.3 meters. First, they retreat 20–30 centimeters from the walls and install the outer beacons. The remaining distance is divided so that the interval between the slats is within the specified parameter.
For fastening beacons they use gypsum mortar, kneading it thickly. Small handfuls of this mixture are applied along the plank placement line. Beacons are pressed into them, placing their backs in the desired plane. If there is a level, the beam from it should slide along them.
When the work is done using a water level, the line of the ceiling surface is transferred to the walls and several laces are pulled so that they are directed along the beacons. According to this marking, the backs are set. After installing all the beacons, the plane is checked using a rule with a bubble level installed on it.
After a few hours, when the plaster has set, they begin the final stage of work, having previously decided how to plaster the concrete ceiling.
Applying plaster
For further work, you need stable construction sawhorses, and the tools you need are a spatula and a platform with a handle (falcon). Selected plaster composition diluted according to instructions. It is necessary that the solution is homogeneous, without lumps.
The putty is spread on the falcon and placed on the ceiling in small portions using a spatula. The solution is used to fill the distance between the beacons. First, the width of the strip is made from 50 to 60 centimeters, and there is no need to achieve a uniform surface.
Then they take the rule, rest it on the beacons and move it towards themselves, swinging it from one side to the other. As a result, a little solution remains on it. It is removed with a spatula and applied to the ceiling - to its unfilled part or where there are holes. Then the rule is moved again.
These steps are repeated until the surface area becomes level. Then they fill in the second lane and so on. The ceiling is allowed to dry for 5 – 8 hours. When the solution has set, but has not yet completely dried, you need to remove the beacons, otherwise they will rust and rusty stains may appear on the surface.
The rustics after the planks are filled with mortar and leveled with a wide spatula to the same level as the ceiling plane. It takes about 5 – 7 days for the plaster to dry completely.
Leveling the ceiling - plaster, is applied before putty, which will be discussed below. If plaster is done correctly, it can last for years.
How to prepare the surface
Before plastering the ceiling, it is necessary to prepare the surface for applying the solution so that the solution adheres to it better. The ceiling should be cleaned of any contaminants and artificial roughness should be created. How long the plaster will last depends on the quality of surface preparation.
The concrete ceiling must first be cleaned and then notched. The notch is made special tool, as a last resort, with an ax or chisel. When making a notch, try to have as many strokes as possible.
If you are going to plaster a wooden ceiling, you need to first fill it with metal mesh or crap.
To fill the shingles, they should be sorted into waste and output.
The shingle should be about 3 mm thick, it can be crooked and narrow. The exit shingles should be 3-5 mm thick.
The plaster adheres directly to the exit shingle.
First, stuff the farewell shit. It should be filled at an angle of 45 degrees to the wall. The distance between individual shingles should be approximately 20 mm. Lightly nail them to the ceiling to prevent them from falling. Thus, the first row is obtained - the exit shingles; the second row - the exit shingles - is nailed to this row. The exit shingle should be located perpendicular to the outgoing shingle.
Exit shingles are nailed at a distance of 25-30 mm from each other, driving nails through one or two shingles. The nails that were used to nail the shingles should be pulled out and put to use. The ends of the shingles must be nailed down, but they cannot be stacked on top of each other.
Plaster
To prepare plaster mortars, binders, aggregates and water are used. All these components are mixed well until a homogeneous mass is obtained. A solution that adheres in a thin layer to the paddle with which it is mixed is considered suitable for use. binding materials. These include: building air lime, podzol, okshara, carbide sludge, clay, building gypsum, Portland cement and Portland slag cement.
Construction air lime is produced by burning limestone. It hardens only in air. This lime is used in the form of lime paste and requires slaking. Before slaking, the lime is ground into a very fine powder. In this form, it is slaked in the solution itself.
Sometimes it is necessary to slak lime into fluff, that is, into a fine powder in cases where there is not enough water. If there is excess water, a lime dough is obtained.
In order to extinguish lime in a powder, you need to take about 1 cubic meter. m of water per 1 cubic meter m lime. Lime should be poured in an even layer on a horizontal surface and watered until a powder forms. If you need to slak the lime before getting the dough, then for 1 cubic meter. m take 3 cubic meters. m of water.
For extinguishing, it is recommended to use dishes with a height of at least 20 cm. Lime is poured into the dish (it is better if it is a box) to 1/4 of the height. Then gradually pour in water in small portions so as not to cool the lime, and mix. As a result, the lime should become liquid and resemble milk. After extinguishing, it must be poured into a special container and kept for at least three weeks. When pouring slaked lime into a storage container, do it through a sieve.
Lime can be replaced with other materials
For example, industrial waste - podzol, okshara or carbide sludge, as well as construction gypsum and Portland cement.
Podzol is a waste product from the leather industry. Consists of third grade lime mixed with hair. Podzol must be rubbed through a sieve before use.
Okshara is waste from the textile industry. It consists of third grade lime and fine wool hair. Before use, okshara should be kept for at least five weeks in an open box in the fresh air to ventilate the chlorine. Carbide sludge is a waste of calcium carbide from the production of acetylene.
It consists of second grade lime, which has a bluish tint, which contains 40% water and undecomposed carbide, and the carbide sludge must be kept in fresh air to remove the odor.
Building gypsum is obtained from gypsum stone by firing. It can be white or grayish in color, representing a finely ground powder. There are 12 brands of building gypsum. It can be used in its pure form, because when it sets, it does not decrease, but increases in volume.
Portland cement and Portland slag cement are among the most durable binders. They harden both in air and in water. Portland cement and Portland slag cement are gray-green powders with various shades.
It should be noted that all binders must be stored in a dry place and must be tightly packed or tightly tied. During long-term storage they lose strength. fillers. River, mountain, ravine or sea sands are usually used as fillers to reduce the shrinkage of the solution and to save binder.
If the sand is dirty, it must be washed. The best aggregate is mountain sand, since it combines best with the binder due to the acute angular shape of the grains.
Pumice and charcoal can also be used as aggregates. Before use, they need to be crushed and sifted. From pumice and charcoal prepare warm light solutions, plaster layer of which must have a thickness of at least 30 mm. other materials. There are a number of materials used to insulate ceilings and to reduce sound transmission.
Such materials include felt, matting and plaster shingles. felt is a felted cloth made of wool, which comes in different densities and thicknesses. matting is a fabric woven from sponge. Only whole and clean cloth is suitable for use; dirty matting must be washed and dried.
Plaster shingles are splinters of different lengths, but always thin. They are packaged in bundles of 50-100 pieces. Instead of shingles, you can use sanded willow twigs. If the rods are too large, they should be split.
Preparation of plaster solutions
Lime mortar is made from lime paste and sand. These components are thoroughly mixed and water is added. The consistency of the solution should resemble thick dough. To give the solution additional strength, add one per 10 liters of solution. liter jar cement.
Lime mortar with gypsum is more durable than just lime mortar. Lime hardens very slowly, and gypsum speeds up this process. This solution sets in 6 minutes and hardens in 30 minutes. The preparation of lime mortar with gypsum must be done in parts.
The preparation process begins with mixing a simple lime mortar. It is prepared in a box, then a small part of the solution (about 3 liters) is removed from the box. Plaster is poured into the free space and water is poured. After mixing the gypsum and water well, return the previously removed lime mortar. The mixture is thoroughly mixed again, adding water if necessary.
The resulting lime-gypsum solution should not be stirred for more than three minutes. The solution must be applied within six minutes, otherwise it will begin to harden. If you succeed liquid solution, then keep in mind that it will set more slowly, it will be easier to apply, but the strength of the plaster will be lower. The thick solution is difficult to apply, but the plaster will be very durable.
Clay mortar is prepared by analogy with lime mortar.
Clay-lime mortar is prepared from clay and lime dough, which are taken in equal proportions. Approximately 4-5 parts of sand are added to the dough. The strength of the resulting solution is much higher than that of clay.
Clay mortar with gypsum is made in the same way as lime mortar with gypsum.
Cement-lime mortar is prepared from cement, lime paste and sand. First, cement and sand are mixed. Then the lime dough is diluted with water until a creamy mass is obtained, into which a dry mixture of cement and sand is poured. The resulting solution is mixed well, adding water if necessary.
Plaster application process
The plaster is applied in three layers. The first layer is a spray, the second is a primer and the third is a covering. With smooth concrete or brick ceiling a thin layer of solution can be applied to it, rubbing it into all surface irregularities. On concrete ceiling the layer of plaster can reach 5 mm in thickness, and on a brick layer at least 10 mm, otherwise the seams of the masonry will be visible. On wooden ceilings The plaster layer must be at least 25 mm. Otherwise, the warping chips may damage it.
Applying a thick layer of mortar at one time is unacceptable, as it will crack when drying. spray The thickness of this layer should be no less than 5 mm and no more than 9 mm. The solution used for spraying should have a consistency similar to sour cream. The spray is applied by spreading the solution in a continuous layer without gaps.
The spray is applied to fill uneven surfaces or penetrate the exit shingle. priming. It is applied to the spray after it has hardened or set. Primer is a solution of dough-like consistency, which is the main layer of plaster. The primer is applied in one, and sometimes in two or more layers. It depends on how thick the plaster should be.
Before applying each subsequent layer, the previous layer must be leveled. Particular care must be taken to level last layer soil. cover. This layer should be applied with a thickness of 2-4 mm. The covering is a creamy solution that is applied to the ground and then leveled well. If the soil is dry, then before applying the covering it should be moistened with water using a brush. It is best to apply the coating to soil that has already set, but has not yet dried.
In this case, the adhesion of the soil to the cover will be especially strong. The covering solution is prepared in the same way as the primer solution, but it is better to use sifted sand, then the surface will be more even and you can do without puttying.
After the cover has set, the surface should be grouted. If the covering is dry, it must be moistened with water using a brush.
Applying the solution using a trowel and a falcon
When plastering the ceiling, transfer the mortar onto the falcon with a trowel, and throw the mortar onto the surface towards yourself over your shoulder.
When throwing the solution away from you, the trowel should be directed slightly to the side.
Throws can be wide, narrow, thick or thin.
In order for the throws to be wide and thin, it is necessary to swing the trowel very sharply.
For narrow and thick throws, the trowel is swung smoothly. The technique of applying the solution requires certain preparation. It will be very difficult for an inexperienced person to apply the solution efficiently, but over time you can achieve excellent results.
How to spread and level the solution
Only the soil and coating solutions are spread and leveled. These operations are usually performed using a falcon or a grater. In order to update only some areas of the ceiling, it is recommended to use a plaster trowel.
When applying mortar using a falcon and trowel, the falcon is held in one hand with the trowel in the other. A portion of the solution is applied to the falcon, brought to the ceiling and pressed with one end so that an angle of approximately 45 degrees is formed between the falcon and the ceiling.
The falcon is then moved along the surface by pressing on it with the end of the trowel. As the falcon moves along the ceiling, the solution is distributed over the surface, and the edge of the falcon that was at an angle is gradually pressed against the layer of applied solution. If you have the appropriate experience, the solution can be applied very evenly.
Applying the solution using a trowel
If you decide to apply plaster to the ceiling using a trowel, you need to put a portion of the solution on it, bring the trowel to the ceiling and, pressing it, move it along the surface in any direction convenient for you. The solution should be applied to the trowel in the form of a bed. The width of the grater blade should not be less than 120-200mm, so that as much solution as possible can be collected at one time.
In order to level the solution using a falcon or a trowel, you just need to repeat the operations without the solution on the tool.
How to grout plaster
Grouting is done after applying the covering. It should be noted that grouting can be done only after the solution has set, but has not completely dried. To do this operation, you will need a wooden grater. If you have correctly calculated the time required for the cover to set, then grouting can be done without first wetting the surface, otherwise the cover must be lightly moistened with water using a brush.
Grouting is done by pressing the float tightly to the surface and performing circular movements with it. When mashed, the solution becomes denser.
After you have grouted, marks in the form of circles may remain on the surface. To smooth them, it is necessary to make a smooth grout.
It is performed immediately after grouting in a circular manner. It is better to perform these operations in stages. Rub first small area surfaces in a circular manner, then “running”, continuing to alternate these stages until the entire ceiling has been processed. If there are bumps or missing spots on the surface after grouting, they will be very noticeable after painting or whitewashing, so grouting must be done very carefully.
Plastering ceilings made of prefabricated reinforced concrete slabs
Precast concrete slab ceilings are found in many apartments. On such ceilings, between the slabs there are rustics, which are rectilinear recesses of the same width. Sometimes floors shrink and the plaster between the slabs falls off. In this case, the plaster must be corrected and new rustications made.
To repair a ceiling made of prefabricated reinforced concrete slabs, you will need the following tools: an even rule, which should coincide with the length of the rust, two or three unplaned slats or thin, narrow boards that will support the rules and plaster mortar. If you use boards, keep in mind that their length should be 5-10 cm greater than the height of the room.
Rules can be continuous or composite. As a rule, they are made according to the length of the rustics. A composite rule is made from two or three pieces and rustication.
Rustication is made from a grater small sizes with a cutout on the canvas and a piece of iron, which is the cutting part. One side of the iron should be sharpened, after which the iron is bent in the form of a semicircle in the shape of a rustic. The diameter of the semicircle should be from 5 to 10 cm.
To secure the rules to the ceiling, you need to press them with slats. This uses the flexibility of the slats, which are installed between the rule and the floor. If the slats do not bend, then wedges must be inserted between them and the rule.
After the rules, slats and rustication have already been made and installed, you need to clear the edges between the slabs and prepare a cement mortar with a small portion of gypsum. The ceiling is coated with this solution, leveled well and rubbed. The edges should be rubbed in especially carefully.
Only after completing all the above operations can it be attached to the ceiling
rule.
In this case, you should pay attention to the fact that when rustication is applied to it, the rustication is between the slabs. Then the rustication is applied to the rule and, pressing, it is carried along the surface of the ceiling, cutting off the mortar to its full depth. After the rust is cut, it is moistened with water and rubbed with a small trowel, eliminating irregularities.
Plaster repair
As a result long-term operation, shrinkage of the house, increased dampness or improper application of the plaster, it may begin to crack, crumble or swell. To correct such defects, it is not necessary to re-plaster the entire surface. It is enough to repair the plaster only in those places where it has begun to deteriorate.
If the plaster has moved away from the surface and began to swell, then in these places it should first be beaten off. Then the surface is prepared for applying the solution and plastered. In this case, it is necessary to thoroughly rub and rub the new plaster into the old one.
If you prefer a painted ceiling, but the paint layer has become too thick, then it needs to be cleaned off. This is done using a scraper or spatula. Paint that adheres very firmly and is difficult to clean must first be wetted hot water using a brush. repeatedly.
Once the paint gets wet, it can be cleaned off without much effort. After cleaning, the ceiling should be rubbed down. To do this, you need to moisten the plaster with water and apply a thin layer of the same solution that was used to make the plaster. The solution is applied in strokes, which are then rubbed with a grater. Try not to leave any gaps. This should give you a thin layer of new plaster that will smooth out any traces of old paint.
When repairing cracked plaster, first widen the cracks using a knife or the end of a cutting tool. Small and shallow cracks are cut to a depth of no more than 5 mm, then the edges are removed old plaster. After cutting the cracks, they are well moistened with water and covered with a solution.
To fill cracks, use the same solution that was used for plastering. The solution should be of medium thickness.
It is pressed forcefully into the cracks, thus filling the voids.
To fill small cracks, you can use pure gypsum paste. To achieve better quality work, it is recommended to add chalk to the gypsum dough. To 1 part of gypsum dough add 2-3 parts of chalk. After filling the cracks with gypsum or gypsum-chalk mortar, they should be primed very carefully. It is advisable to do this in two layers. The primer of the painted areas is done so that the gypsum absorbs the paint composition as little as possible, without forming stripes and stains on the surface. Grouting of covered cracks is carried out in the usual way, but carefully rubbing the solution onto the old plaster.
One of the methods for leveling walls is plastering. It is used most often. How to choose plaster for each room, which brands are better, how to make cement mixtures with your own hands - read on.
Types of plaster
Any plaster consists of a mixture of a binder, sand of different fractions and additives that give the composition specific properties. First of all, they are distinguished by the type of binder. It could be:
- gypsum;
- cement;
- lime;
- clay.
The most commonly used are gypsum and cement plasters. They are the most practical; with their help it is easier to obtain a flat surface. Because it's cement sand mixture(CPS) turns out to be very hard and not very convenient to work with, lime is added to the solution. Such plasters are called cement-lime plasters. To choose plaster, you need to know where exactly the walls will be leveled - outside or inside the room and what the conditions are in this room (more on this below).
You can make cement-based plaster mixtures yourself. This saves money, but takes more time. Can be purchased at finished form- dry mixture, packaged in bags. Gypsum plaster is rarely made with your own hands; more often you buy it ready-made.
Plaster and putty are often confused. The processes are somewhat similar - both are used to level walls. But walls and ceilings are plastered if there is a large curvature - from 5 mm or more. After plastering, the surface is even, but grainy (less grainy when using gypsum compounds) and needs to be smoothed. And smoothing is done using putties. They contain more finely ground components, which results in a smooth surface. The maximum layer of putty is 5 mm, plaster is 50-80 mm in one layer, and several of them can be applied.
Which is better - gypsum or cement plaster?
You need to decide which plaster is better to buy - gypsum or cement - based on their qualities. What is a plus in one room is a minus in another. Therefore, first we will consider the properties of cement and gypsum plaster.
| Property | Cement plaster | Gypsum plaster |
|---|---|---|
| Vapor permeability | 0.09 mg/mhPa | 0.11-0.14 mg/mhPa |
| Average consumption per square meter with a layer of 1 cm | 12-20 kg/sq.m | 7-10 kg/sq. m |
| Setting time | about 2 hours | less than 1 hour - about 40 minutes |
| Hygroscopicity | is not afraid of moisture, does not change properties when wet | getting wet is undesirable, maximum humidity is 60% |
| The need for putty | needed for all types of finishing except laying tiles | only needed for painting |
Let's start with economic feasibility. If we compare only the price per kilogram of dry composition, then cement-based compositions are about 1/3 cheaper. But since their consumption is about the same amount more, the total amount spent on plaster will be approximately the same. So there are no priorities here and you won’t be able to choose plaster based on price.
The easier it is to work
If we compare cement and gypsum plaster in terms of ease of use, then the gypsum composition is easier to apply. It is more elastic and “sticks” to the base better. But there is one “but” - it sets faster. On the one hand, this is good - it dries faster to a state where the next layer can be applied and the work moves faster. On the other hand, this is bad - you need to mix small portions at one time: in order to have time to finish everything in 30-40 minutes. It is better not to use set mixtures, since adding water changes its condition only externally. This material will no longer gain normal strength.
Cement compositions retain elasticity for 2 hours, so large volumes can be mixed at a time. But such plaster also takes longer to dry, so the process takes longer - you have to wait for the composition to dry.
Application area
When choosing between gypsum and cement plaster, it usually all depends on the area of application - gypsum is not used outside because of its fear of moisture. In this case, choosing a plaster is simple: for exterior work we use cement plaster.
The same property determines its scope of application in interior spaces: for the bathroom and kitchen it is better to use cement plaster, which is not afraid of moisture. In all other “dry” areas, they prefer to level the walls with gypsum compounds. They “fit” better and, with some experience, you don’t have to put putty on the walls under the wallpaper - you just need to level the grout layer well.
Plaster is the basis of the finishing pie, so it must hold up very well
There are, of course, gypsum moisture-resistant plasters. Their moisture resistance is increased through the use of hydrophobic additives, but this is reflected in the price - it is significantly higher than for conventional compounds. It is also worth saying that in the bathroom the walls are leveled with gypsum compounds that are not moisture resistant. The tiles will then be laid on it, and if you carefully grout the seams with moisture-resistant grout, the moisture will not reach the plaster. But this is still not best way out, since gypsum and cement are very different in characteristics, and tile adhesive is always made on the basis of cement. If you lay tiles on gypsum plaster, in most cases they lag behind the base, as they say, “bump”, and may even fall off.
If you are choosing the best way to plaster the ceiling, in dry rooms the choice is clear - gypsum plaster. It is lighter, has better adhesion, and is easier to level. And even in damp rooms it is better to use a moisture-resistant gypsum composition - it is very difficult to work with cement on the ceiling. This is the case when it is better to overpay a little. So choosing plaster for the ceiling is simple: it is a gypsum composition.
DIY plaster mixture
With a limited budget for construction or renovation, you have to think about saving. Choosing plaster here is easy: you can save on finishing costs if you make cement-based compositions yourself. It's really cheaper, although it requires additional time and effort. But remember that in ready-made compositions additives have been added to improve the properties of the plaster. For example, antifungal additives are added to formulations for wet rooms to prevent the development of mold. In compositions for plastering external walls, an additive is added to the antibacterial ones to increase frost resistance. There are also plasticizing additives that make application easier. In principle, you can also add these additives to homemade plaster. You can find them at construction markets or in specialized stores, the standards are written on the packaging. And even taking into account the cost of additives, the savings when making it yourself will be significant - about 30%.
It’s not difficult to make cement-sand or lime-cement plaster with your own hands. Mix the components in certain proportions in dry form, then add liquid components (if any and water), bring to a certain consistency. You can mix it manually with a shovel in a large basin or trough. You can mechanize the process if you have a drill - using a special attachment. The easiest way is using a concrete mixer. With it, things go faster, but large volumes are difficult to produce, especially if you have little experience.
Cement-sand mixture: proportions
The cement-sand mixture is made up of 1 part M400 or M500 cement and 3-5 parts sand. The cement must be fresh, the sand must be dry, sifted through a fine sieve with a grain size of no more than 1.5 mm. Take 0.7-0.8 parts of water. As you can see, the proportions are approximate. Sand can be of different humidity, the solution can be used for plastering walls in different rooms, cement may be different brands. When choosing the amount of water, the main guideline is ease of use. It is necessary to select the composition so that it is not so thick that it falls off the wall, but not so liquid that it slides. This is determined experimentally.
There is also a difference in composition depending on the area of application. To plaster exterior walls, take 3-4 parts sand to 1 part cement. To level the walls indoors, more sand is added - 5 parts or even more.
Although the DSP is much cheaper ready-made mixtures, it is more difficult to work with - it does not stick to the wall very well, it takes a long time to dry, and when dry it almost always becomes covered with cracks. But it is not afraid of moisture and for this reason it is recommended for plastering walls in damp rooms, which will later be either MDF or any other). For other types finishing- painting and wallpaper - it is better to use cement-lime mortar or gypsum.
DIY cement-lime plaster mortar
Cement-lime plaster is made with the addition of lime paste. Parts of lime are measured out in the form of a dough, then diluted with water to a liquid state and in this form added to thoroughly mixed dry cement and sand.
The proportions of cement-lime plaster are as follows: for 1 part of cement take from 1 to 2 parts of lime paste, 6-9 parts of sand. Water is added to bring the solution to the desired consistency. The sand is the same as for DSP - with a grain size of no more than 1.5 mm, the water is clean, without contamination. Lime dough is better than store-bought. When extinguishing at home, there are still particles that have not reacted. Later, when the wall gets wet, they react and increase in volume, which causes pieces of plaster to fall out. Therefore, it is better not to save on this.
The exact selection of proportions is determined experimentally: the mass should stick well to the wall. Walls in any premises can be plastered with a cement-lime composition. The composition is softer, more convenient to work with, and does not crack when dry. But the strength of such plaster is much lower than DSP and this must also be kept in mind.
Selecting ready-made formulations
Choosing the type of plaster - gypsum or cement - is just the beginning. Next, you will have to choose the manufacturer and the composition itself - there may be several products with slight differences.
Good gypsum plasters
The most popular gypsum plaster is Rotband from Knauf. This is a really high quality product that is easy to use even for beginners. The same company has other products - Goldband and HP Start. They are cheaper, and the quality is quite decent.
The most popular type of plaster is Rotband.
NR Start is a gypsum-lime composition, Goldband is a gypsum composition. The difference between Rotband and Goldyuand is the thickness of the minimum layer. Rotband’s is 5 mm, the second’s is 8 mm. Otherwise, the technical characteristics are very similar - both consumption (8.5 kg/m 3 with a layer thickness of 1 cm), and maximum layer (50 mm), and compressive and bending strength. The density in the hardened state is slightly different: ~980 kg/m 3 for Goldband and 950 kg/m 3 for Rotbabd. Scope of application - any residential and non-residential heated premises, including kitchens with bathrooms.
| Name | Purpose | Color | Layer thickness | Binder type |
|---|---|---|---|---|
| Knauf Rotband plaster mixture | For plastering smooth surfaces of walls and ceilings | White gray | 5-50 mm | Gypsum with polymer additives |
| Plaster-Adhesive Mixture Knauf Sevener | For restoration of old plaster surfaces, including facades | Grey | Portland cement with polymer additives and reinforcing fibers | |
| Plaster Bergauf Bau Interier | For plastering in rooms with normal humidity | Grey/White | 5-40 mm | Cement with polymer additives and perlite filler |
| Plaster Volma-Canvas | For interior spaces with normal humidity | 5-50 mm | Based on gypsum with chemical and mineral additives |
They also speak well of gypsum plaster Volma Layer, Found Gipswell, Eunice Teplon, Prospectors. They cost less, give good results, but it’s still easier to work with Rothband and the “company”. Based on the results of working with these brands, there are both positive and negative reviews, but in general, the quality is not bad.
Ready-made cement plasters
Cement plasters are available for manual and machine application. We will talk about the compositions for manual application. For interior work Forward, Weber Vetonit, Osnovit Startwell, Weber Stuk Cement are good. They fit well on a clean, pre-moistened surface. For better grip better than walls pre-prime, after drying, start on your own
If you choose cement-based plaster for exterior work (including for plastering an open loggia or balcony), you need façade compounds. They are different from the usual ones increased amount freeze/thaw cycles. Facade cement plasters - Yunis Silin facade, Osnovit Profi Startwell, Knauf Unterputz, Bergauf Bau Putz Zement. Ceresit CT 24 Light plaster is suitable for both facade and interior work.
For walls made of cellular concrete special plaster is required. It has increased vapor permeability to prevent moisture from being trapped inside the wall. This is Ceresit CT 24, Knauf Grundband (contains tiny particles expanded polystyrene, which increases it thermal insulation properties, reduces consumption).
High-quality plastering of the ceiling surface with cement mortar
Until now, ceiling plaster is the most common finishing option that is used everywhere. In any apartment, office, country house, at an industrial enterprise, in a workshop, in a warehouse - everywhere you can see a flat surface covered with a layer of gypsum mixture.
In any city it is easy to find a master who will masterfully perform the work described. But the technology of applying plaster itself is so simple that you can master it yourself. This finish has significant advantages over other options. But there are also disadvantages. Therefore, before you choose this type finishing, it’s worth weighing the pros and cons.
Advantages of plastering ceilings
The described technology has a number of advantages. This:
- Relatively cheap. The cost of materials for work will be significantly lower than what you will have to spend on any other finishing option.
In addition, primary plastering of ceilings is a mandatory step in most alternative finishing methods. And those who decide to carry out such work on their own can save a lot on attracting professional labor. It’s no secret that two-thirds of the cost is paid for someone else’s labor.
Therefore, today such ceiling repairs are often classified as in the middle price segment.
- Space saving is another positive advantage of plastering technologies. They help reduce height loss to a minimum - the correct layer of plaster takes only 3 centimeters. And for small apartments with very low ceilings this is quite relevant.
- Versatility of use. This circumstance helps to use plaster when finishing any surface - be it concrete, brickwork or wooden partitions. It will hold up very well and equally reliably on any of these types of floors. It is enough just to choose the correct composition of the mixture and observe in detail the features of repair technologies.
Method of plastering the ceiling
As you can see, the above arguments indicate a worthy finishing material, which can easily meet the requirements of modern times.
But it is worth mentioning the disadvantages of this option. Applying plaster is a very labor-intensive process that requires special professional skills. Any deviation from repair technologies will lead to disastrous results: the plaster ceiling may crack, and then the finishing will partially or completely collapse.
Modern mixtures can withstand even high room humidity, but cannot “survive” the flooding of neighbors. In this case redecorating will definitely be required, and it will provoke new expenses.
Despite all these disadvantages, this method of finishing ceilings continues to be very popular. Today this is the most understandable and accessible view repair work, which is easy to do with your own hands.
How is plaster different from putty?
Many people often confuse ceiling plaster with finishing putty. These are completely different repair technologies. The first is to eliminate height differences, level the surface and prepare it for applying the finishing layer - putty. It is carried out using coarse mixtures based on cement and gypsum.
Applying the mixture to the ceiling
Putty is a finishing leveling layer that is applied to the plastered surface. Putty is performed using finely dispersed mixtures, the main ingredient of which is building gypsum. The thickness of the last layer does not exceed 3 millimeters, while the plaster can be up to 5 centimeters thick.
How to apply plaster correctly?
To perform the described repair work, you must first stock up on materials and tools. You may need:
- Construction mixer.
- Container for mixing a special mixture.
- Narrow and wide spatulas.
- Roller for applying primer.
Step-by-step instruction
Preparation of the solution
Before you get started, you need to choose the right mixture. As a rule, the product label indicates what kind of work the material is intended for: for external, internal, for rooms with high humidity, for subsequent decorative finishing or wallpapering. Once the plaster for the ceiling has been selected, the main work can begin.
- The first step is to thoroughly clean the surface. Experienced craftsmen They try to approach this process very responsibly. Otherwise, the layer of old plaster or whitewash under the layer of wet mixture will swell and may cause a violation of the integrity of the coating.
- The second step is to thoroughly prime the base. The primer provides better adhesion between the putty mixture and the ceiling surface.
- The third step is to thoroughly stir the mixture. As a rule, any packaging indicates the right proportions. In a large container you need to dilute the solution to the consistency of very thick sour cream. It will adhere well and evenly cover all existing irregularities and defects.
- The fourth step - using a small spatula, you need to fill large cracks, chips and all potholes with the plaster mixture. Further, if it is necessary to apply plaster in a layer of more than one centimeter, it is advisable to glue a special mesh - serpyanka - to the surface of the ceiling.
It is similar to gauze, and its task is to create a reinforcing surface. Serpyanka is glued using PVA glue, but you can also find self-adhesive mesh. If the plaster is applied in a layer of less than one centimeter, only the joints of the ceiling tiles can be glued with sickle.
Work process
- The fifth step is direct plastering of the ceiling. The solution is applied to the half-ter using a small spatula, which helps to evenly distribute the mixture over the entire surface.
Remember that the smaller the layer of plaster, the more securely it will adhere. If the height differences are large, you should not immediately apply a thick layer of material. It is better to do this in several stages - apply several layers, each time waiting for the previous one to dry completely and priming it again before applying the next layer.
Experts warn that the maximum number of layers of plaster and primer should not be more than three. Otherwise, the finish will simply begin to flake off and fall off.
- The sixth step - the finishing coat must be lightly sanded and re-primed.
If the technology described above is difficult for someone to understand, they should think about hiring professional workers. But believe me, it’s not difficult to master and do all this work yourself. It is enough to watch a training video and practice a little on some technical object. Then plaster and level the ceilings without outside help it will be much cheaper.
- Plastering the ceiling
- Grouting the plastered surface
In order to describe as clearly as possible how to plaster a ceiling with your own hands, let’s take as an example small room. For this we will need the following materials:
- laser or water level;
- rule;
- lighthouses;
- gypsum plaster;
- self-tapping screws with dowel;
- gypsum plaster.
Tools for applying plaster.
Before you start plastering, you need to carefully mark and prime the surface.
Marking the ceiling surface and priming it
First you need to correctly mark the ceiling.
Beacons on the ceiling should be placed in the direction of light falling from the window.
This is necessary so that if some error occurs when installing the beacons (most often the average beacon is installed incorrectly), it would not be so noticeable. It is necessary to take into account such subtleties, because when placing beacons across the room, the light falling from the window will reveal such an error.
Scheme for marking a room with beacons.
Depending on the width of the room, beacons are installed. Up to three meters - two rows of beacons are installed, each row is installed at a distance of about 60 cm from the walls. The process of plastering ceilings with your own hands takes place in the following sequence: first plastering middle lane, then two side ones. In rooms with a width of 3 to 5 m, beacons are placed in three rows. If the width of the room is more than 5 m, then there can be four rows, etc.
As an example, we took a room with a width of 3.5 m, so we will need to install three rows of beacons. We install two rows near the walls, retreating about 20 cm from them, and we place the last one along the center of the room, thus as if dividing it in two. In this case, you can begin the plastering process in the direction from the center of the room to its wall. In this case, the length of the rule allows you to do this. The first beacon in each row should be about 2.5 m, slightly less than the length of the rule for plaster. The second one can be any size.
Then you need to note in which places the screws will be screwed in; they are needed to correctly mark the height difference in the room. For your convenience, you can immediately write on the ceiling where each beacon will be located, so as not to re-measure them. After the marks for the screws have been made, use a puncher to make holes in the places of the marks and install dowels into these holes.
The sequence of applying primer layers to the ceiling: 1 – first layer; 2 - second layer; 3 – direction of light rays from the window.
Before you start screwing in the screws, you need to prime the entire ceiling. Primer for plastering work in construction stores there is a great variety, so choose it in accordance with the surface that you are going to plaster. If the surface is smooth, then a stronger primer is needed, for example betokontakt. When treating the surface, you should not skimp on the primer. After you have completely treated the entire ceiling area, you need to let it dry.
Once the primer has dried, you will need to find the lowest point in the room. To find this point you can use laser level, if you don’t have one, then a simple water level will do. To measure with a water level, you need to tie it to a rule and measure starting from the corner of the room, while noting the height level of each section near each hole for the screws. The purpose of these measurements is to find the lowest point where the thinnest layer of plaster will be. If you make a mistake when measuring, then overuse of plaster may occur and the layer will come out very thick.
Or at the end of the work you may come up against a ceiling plane on which it will not be possible to apply even the thinnest layer of plaster. Application methods decorative plaster
on the ceiling. When the lowest place is near drilled holes
found, screw the screw in there so that it sticks out about 5-7 mm. This is the thickness of the plaster beacon. Since the screw was screwed into the lowest place of our ceiling, other screws will stick out a little more. We take the second screw and screw it in approximately at the same level as the first. We check the horizontal between them using the rule, using a water level we check the second self-tapping screw relative to the first.
Depending on what the level shows, we screw in or unscrew the screw, while not forgetting to check each action with the level. We adjust the following screws in the same way; be sure to check the level between them. To mark using a water level, you will have to spend about 2 hours of your time. With laser, everything is much simpler; the whole process will take about 20 minutes.
Plastering the ceiling
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The principle of plastering the ceiling is the same as that of plastering walls, that is, apply plaster to the ceiling and remove excess. You can apply the solution different instruments depending on the thickness of the layer. If the layer thickness is less than 1.5 cm, then it is better to use a steel trowel.
Scheme for applying plaster using a crumb thrower.
You need to put a small amount of solution on it and gently spread it over light ceiling movements with pressure. If your layer is more than 1.5 cm, then it is better to work with a spatula. When you mix the solution, you need to remember that a solution that is too thick will not apply well to the ceiling and will fall off under its own weight. Therefore, the solution should be made not very thick so that it sticks to the surface better.
If the solution is thick, so-called bubbles may appear. These are places where the solution did not adhere to the surface of the ceiling; it sagged under its own weight, and thus an air bubble formed. Most often, such bubbles appear in the corners. To avoid this, you must first apply a thin layer of plaster, and then apply the main one. The point is that the solution sticks very well to the solution and no voids are formed.
The second layer must be applied before the first dries so that the layers can bond better. If you apply a second layer after the first has dried, cracks may form on the surface of the plaster, and you will have to remove the entire layer so that it does not fall off on its own in the future. And with bubbles it’s even easier, you need to wait until the solution dries and use a spatula to remove the place where it forms down to the very base. And then put new plaster on this place.
It is better to carry out the plastering process with your back to the window, so the light will not disturb you. Removal of excess solution occurs by moving the rule or trowel towards you. The finishing movement, on the contrary, is done independently, so the light from the window will allow you to see the gaps between the plaster and the rule and quickly respond to possible problems.
After applying the plaster to the main areas of the surface, there may be places along the walls where the plaster has not yet been applied; you also need to remember to unscrew the screws. They may prevent you from leveling the mortar with the rule, and after grouting they may be visible even under a layer of putty. The holes from them and places along the walls are sealed after the plaster has dried. After this, we remove all the beacons and seal the resulting furrows.
