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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.
With beacons or without
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.
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.
What is the best plaster
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.
| Name | appointment | Color | Layer thickness | binder type |
|---|---|---|---|---|
| Plaster mixture Knauf Rotband | For plastering smooth surfaces of walls and ceilings | White gray | 5-50 mm | Gypsum with polymer additives |
| Plaster-Adhesive Mix Knauf Sevener | For restoration of old plaster surfaces, including facades | Gray | Portland cement with polymer additives and reinforcing fibers | |
| Plaster Bergauf Bau Interior | For plastering in rooms with normal humidity | Grey/White | 5-40 mm | Cement with polymer additives and perlite filler |
| Volma-Holst plaster | For interiors with normal humidity | 5-50 mm | Based on gypsum with chemical and mineral additives |
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.
Primer, why is it needed and which is better
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.
Now 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.
How to seal the joints of plates and rusty
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.
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.
Sometimes 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 work - Take a rag, moisten it with Betonokontak, hammer it into the slot. Leave on the duck, then plaster.
The 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.
Do-it-yourself ceiling plastering on lighthouses
If 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.
Prepare
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.
If 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.
Installation of beacons
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.
The same operation can be done with the water level, but it will be much more difficult. First you need to draw a horizontal line along the perimeter of the walls at some arbitrary distance from the floor. We fix one end of the level at this mark. With the second we go around the room, measuring the distance from the water column in the level – to the ceiling. So calculate the same maximum and minimum points.
Having decided on the thickness of the layer, select the beacons. These are galvanized perforated planks with a protruding back. These backs will be the supports when leveling the mortar. The beacon back height can be 6 mm and 10 mm. We choose the one that is slightly larger than the maximum deviation found.
Beacons are placed in increments, slightly less than the length of the rule – a tool that levels and cuts off the solution. With a rule length of 1,5 meters, beacons are placed at a distance of 1,1-1,3 m. First, they put the extreme beacons, stepping back from the walls 20-30 cm. The remaining distance is divided so that the distance between the beacons is within the specified limits.
Beacons are attached to the gypsum mortar, knead it thickly. Islands of this solution are applied along the beacon installation line (can be drawn on the ceiling). Lighthouse strips are pressed into it, exposing their backs in one given plane. If there is a plane builder (level), everything is simple – we expose it – the beam should slide along the back.
If we work with a water level, we transfer the required “finishing” ceiling level to the walls, we stretch several cords so that they are directed along the lighthouse. On these cords and insert the backs of the slats. Having set all the beacons, check the plane with a rule with a bubble level installed on it.
After the gypsum has set (several hours should pass), you can start plastering the ceiling.
Applying and leveling plaster on the ceiling
At this stage, stable construction goats with a large platform between them will be required for work. Of the tools – a small spatula and a construction falcon – a platform with a handle.
Dilute the selected plaster mixture strictly according to the instructions. The solution should be homogeneous, without lumps. A solution is applied to the falcon from the container, then it is placed in portions on the ceiling with a small spatula. It is probably more convenient to send the solution with a sharp movement of the brush, but you can simply “stick” the solution to the ceiling. Here everyone chooses his own way.
The distance from one lighthouse to another is filled with plaster. The width of this strip to begin with is 50-60 cm. When laying, you should not achieve a uniform surface. It is filled with chaotic strokes.
We take the rule, rest it on the beacons, move it towards us, swaying from side to side. With this movement, a certain amount of solution remains on the bar.
We remove it with a small spatula and send it to the ceiling – to the unfilled part or where the pits were found. After filling the holes, we again draw the rule. These are the basic techniques for plastering the ceiling, we repeat them until the site becomes even.
So, gradually, one strip is filled, then the second, and so – the entire ceiling. Let it dry for 5-8 hours.
Extraction of lighthouses and sealing of rusts
When the solution has set, but not yet dried, the beacons are taken out. If you leave them, the metal will begin to rust, rusty stains may appear on the ceiling.
The rusts remaining after the lighthouses are filled with the same solution, leveled to the same level with the ceiling plane using a wide spatula. There is no point in using a melter – it is too long. After that, we can assume that the plastering of the ceiling with your own hands is finished. It remains to wait for it to dry completely. This will take from 5 to 7 days – depending on the composition.