When installing interfloor ceilings from prefabricated reinforced concrete slabs, flooring between the slabs there are seams that do not flush up, but embroider - stretch or cut in the form of rusts. Rusts hide the resulting cracks.

Prior to embroidering, the joints between the plates are filled with tow and compacted - they are soaked so that the tow is recessed into the seam to a depth of 15-20 mm.

For joint expansion, a simplified template board is used (Fig. 80, a), one side of which is cut into a “mustache” at an angle of 45 °, and a reinforcing wire 10 mm thick is reinforced with nails in the middle of the board on both sides. Pre-bend the wire. You can make an ordinary, small template (Fig. 80, b). With the help of templates, rusts are pulled over a fresh solution.

Fig. 80. Patterns for stretching or cutting rust:
  a - a simplified template, b - ordinary, c - rusting-grater

Rusts can be cut using a special rustik-lutherka (Fig. 80, c) of small size with a cutout on the canvas.

A steel plate curved in the form of a semicircle with bent edges is attached to the cutout.

Holes are punched in the edges for fastening the half-ring to the canvas with nails.

The rules are fixed to the ceiling with two or three thin rails 10-15 cm longer than the height of the room (Fig. 81). Reiki set obliquely on the floor. First, with two slats 2, the ends of rule 1 are pressed, and then the middle of the rule is pressed with an additional rail. Spring rails hold the rule firmly. If the flooring plates are accidentally laid not on the same level, then they make a second template, in which one excuse is lower than the other. To fill the joints used cement or cement-lime mortar. For the speed of setting, no more than 10% of gypsum is added to it.

Fig. 81. Fastening the rule using flexible rails:
  1 - rule, 2 - slats

The solution fills the seam flush with the plates and wipes well. After that, the rule is fastened to the ceiling so that the rust appears in the center of the seam, put a rust-and-half grout to it, and, clicking on it with the necessary force, lead the steel half ring forward, cutting off the solution. This operation is repeated several times until the solution is completely cut off and the rust is formed. The cut out rust is corrected and rubbed with a small trowel.

Whatever methods the builders use when building a building, it changes over time. This is a natural time process. It is influenced by weather conditions in your area - the soil freezes and then thaws. Constant seasonal temperature changes also contribute to this, building structures age, the foundation gradually sags, the walls of the building become deformed. As a result of all these changes, rusty occurs on the ceilings of the building.

Technological reasons

Modern methods of construction make it possible to dispense with the installation of ceilings without seams.

This was not always the case - in old buildings on the ceilings, ledges or rusty between the ceiling slabs are clearly visible. The presence of cracks in the ceiling was due to construction methods. Each owner of the apartment himself decided how to close up the rusty on the ceiling. Usually they were embedded in the form of neat grooves, noticeable with any quality of finish.

Rust on the ceiling is a consequence of the displacement of the ceiling concrete panels due to natural movements. Almost all old buildings are affected by this defect.

The choice of the desired method of eliminating cracks between the ceiling panels depends on the size of the rust. If the size of the crack is small, then it can be easily covered with a solution of gypsum, and with a distance between the plates of 3-4 cm, you will have to plaster the entire ceiling, only after the completion of this work, the rusts will become invisible.

Note! If the difference between the ceiling plates is more than 4 cm, the only right solution is to install a suspended or suspended ceiling.

Preliminary work

With any method of removing rust, you choose, you should free the ceiling from the old layer of whitewash or paint. Whitewashing is removed with a simple spatula. The work is very dirty and dusty, before you start you should not forget about protecting your eyes and respiratory organs, moisten the ceiling with plenty of warm water.

The work of removing paint is more complicated, this is due to the fact that its coefficient of setting is much higher. Sometimes it is better to remove the paint along with a layer of plaster. You can remove the paint from the ceiling with a grinder. This method is also very dirty and dusty.

Note!   Whether to completely remove the plaster or not, you decide for yourself. Check how it hangs on the ceiling. If it is easily removed, then it is better to remove it. Use a hammer and a chisel for this.

If the plaster adheres well to the ceiling, then experienced craftsmen recommend leaving it.

If you decide to repair only the cracks, and the differences between the plates are insignificant, then examine the rusts. Tap them, if you find weaknesses, voids, remove the plaster in these places and repair the cracks.

When shifting the plates by 10 mm, you will need to level the entire ceiling surface, and this involves the removal of all the finishing layers to the concrete base of the floor. Before starting this work, you need to free the room from furniture, and the rest - it is good to close the film. When carrying out work to remove a layer of plaster, observe the rules of personal protection. Use a gauze mask to protect your respiratory organs, hands should be protected with gloves.

Rust repair

You have successfully completed the preparatory work, now you can begin to repair cracks between the ceilings. To do this, you must have in stock:

• serpyanka 200 mm wide
• polyurethane foam,
• plaster.

To close a crack qualitatively, it is cleaned and deepened. With a small size of the crack, it is cleaned with a chisel or spatula from debris, dust, pieces of plaster or old whitewash.

The size of the rust is significant or the shift between the plates is 10 mm, it must be expanded. An ideal rust should look like a recess having a triangular section 50 mm wide. To give it the right look, use a chisel, then remove all the debris from it, treat the rust with a polymer primer.

After drying, take a damp cloth and wipe the rust, and then cover it with foam. After a day, cut off the remaining foam, make sure that it does not go beyond the level of the ceiling surface.

Prepare cement mortar. Use a spatula to place it inside the crack. Try to tightly fill the groove in the rust. After setting the mortar, cover the surface of the rust with a streak of sickle, check that its middle coincides with the center of the crack.

No repair can be perfect without a flat ceiling. It is for this reason that the problem of how to close up rustics on the ceiling worries all apartment owners in panel houses built in Soviet times. Even those seams that were carefully repaired diverge over time for completely natural reasons - plate movements and house subsidence. Rusty on the ceiling is the junction of the slabs and, in perfect condition, it looks like a rather neat depression with a width of 50 mm with oblique smooth bevels. By the time when repair is required, the situation in reality is far from the standard. In the best case, the solution cracked and in places crumbled out, in the worst case, the divergence of the plates, which requires equalization of the entire flow.

Preparation and determination of the amount of necessary work with the ceiling

Any repair of rustics on the ceiling begins with preparation. The decorative coating is peeled off, whitewash and water-soluble paints are washed out. Here.

The seam is embroidered with a spatula. The crack expands, all crumbling sections are removed. If the solution easily breaks off, then it is worth removing it completely to concrete, this will get rid of further delaminations when painting the ceiling.

Before closing the joints on the ceiling, a visual inspection of the damage and measurement of the displacement is carried out. In cases where the difference does not exceed 5–7 mm and the crack width is small, then it can simply be repaired without subsequent alignment of all surfaces. If the difference is significant 7–10 mm, then after closing the rust on the ceiling, you will have to stretch the surface to level the difference. For more significant defects, the installation of false ceilings is recommended. It is possible to even out large differences with a solution, and some materials allow you to apply a large layer, but it will cost more. In this case, it is much more rational to use drywall systems or suspended ceilings.

Work order

Proper repair of rustics on the ceiling is a guarantee of the absence of cracks for several years. For work, we need:

• primer that improves the adhesion of materials, best concrete contact and its analogues;
• fiberglass mesh (serpyanka);
• steel spatula;
• stucco gypsum mixture (Rotband, Prospectors, etc.);
• with a large gap width - mounting foam.

Thoroughly moisten the surface of the rust with a primer and wait until it dries completely. With a large crack width, fill it gently with mounting foam so that it does not protrude below the ceiling surface and leave for a day. Before closing a crack in the ceiling, it is necessary to fill it with a stucco mortar.Rothband is ideal for about a third and lay a sickle , so that the middle of the tape coincides with the center of the rust. Fiberglass tape will serve as reinforcement, it will protect against cracking, even with small movements of the plates, which are inevitable in the future.

After that, the deepening of the rust is carefully filled with gypsum plaster and leveled. If there is a slight difference, then it is necessary to putty the entire surface area, which turned out higher. It is convenient to use a steel rule to level the layer. If the experience of plastering allows, you can use a more convenient and lightweight wide spatula.

After drying, the entire putty surface is leveled using a special grater or grinder. The further order of work depends on the method of finishing. Also come to eliminate any defects. If you need to close a hole, a crack or a chip on the ceiling, they must also be cleaned,. For defects of a considerable area, use reinforcement with fiberglass or metal plaster mesh.

Seam Finish

After the restored rusts have completely dried, you can proceed to preparing for the finish. If the difference was insignificant, then the entire surface is primed with a penetrating solution. After that they simply putty the finishing gypsum mixture (KNAUF, Volma and their analogues). After a thorough grout, such a ceiling is re-primed. Now the surface can be painted, papered.

If the difference was significant, then the ceiling needs alignment. Minor irregularities can simply be gently pulled out with a layer of plaster, making the unevenness almost invisible. But, this method of solution is not always suitable. In such cases, a complete surface alignment is necessary. This work is rather laborious, it will require not only a lot of patience and diligence, but also the presence of comfortable goats. If the total layer of plaster exceeds 5 mm, the use of beacons is recommended.

With differences in height of more than 10 mm, all experts recommend the installation of a suspended ceiling, but rusty must first be repaired. It is rational for these purposes to use polyurethane foam, since subsequently they simply close, and a neat appearance is optional. After that, the ceiling can be leveled with a drywall construction or with the help of tension systems. The resulting surface will be perfectly smooth.

Video: How to deal with large cracks in the ceiling?

Video: Sticking the grid on the joint.mp4

Thin coat plaster . Thin-layer plaster is applied only on stone, brick, concrete, reinforced concrete, slag concrete and other stone-like surfaces. On wooden, straw, reed and fiberboard surfaces, the thickness of the plaster should be at least 20 mm, regardless of the type of plaster.

With a bast thickness of up to 7 mm, a plastic solution is prepared and applied in one layer at a time, carefully leveling. With a bast thickness of 10 mm, the solution is applied in two layers: spray and soil. Before applying the solution, the surfaces are moistened with water. If the thin-layer plaster is high-quality, beacons are arranged.

Mesh plastering . Mesh surfaces prepared for plastering are stained with a creamy cement mortar or cement paste. Staining is repeated two to three times after 4-8 hours with a slight pressure on the brush. Sometimes a creamy solution is carried out on a grid of spray with a spatula with a falcon. The spray is applied in two to three doses two to three hours after each application. The solution covers the grid with a thin layer, giving it the necessary rigidity, and it ceases to vibrate. Then plastering is carried out in the usual way. The solution is often smeared with the back of the scapula.

A cement mortar is prepared in this sequence. First, a dry mixture of cement and sand is made, fibrous additives are added there and everything is thoroughly mixed, then water is poured. Cement-lime solutions are prepared first, as well as cement. After this, the lime dough is diluted with water, mixed and get a thick lime milk, which mix the mixture.

After the mesh cells are smeared or covered with a solution, a day later they begin to apply the solution in the usual way - by pouring or spreading.

If plastering is carried out by beacons, then after closing the mesh cells with the mortar and setting it (in a day or later), they begin to hang, arrange grades and beacons, which are used for plastering in the usual way. Lighthouses are best arranged in the same way as on concrete surfaces, using a rule with a level. Often lighthouses arrange it like that. First, nails are frozen in the solution, the surface is checked according to them and marks are made on the nails, to which the rule is attached, and the solution is applied under it. Gypsum beacons after applying the soil are cut down, their installation site is cleaned of gypsum, moistened with water, sprayed and coated with a solution, which is then leveled. After that perform nakryvka and grout.

Rust finish between floor slabs . Prior to finishing, it is necessary to prepare the seams. They are cleaned with a steel brush or chisel. Then the gap between the plates is filled with tow, compacted, but so that it does not reach the front surface by 15-20 mm.

The seams between the floor slabs are flush coated with mortar slabs, level it and rub it. To make sedimentary cracks between the plates less noticeable, a small semicircle is arranged in the solution - rust. This whole process is called rust finishing.

There are two ways to finish rust. The first is that a rusted mortar that has been slightly set is cut through with a rustik (Fig. 47, a). The second method is that the rust is pulled over a fresh, uncured solution, using the simplest template for this purpose (Fig. 47, b). It is made of a board of the desired width, cut at an angle of 45 ° on one side.

In order for the rustics to be straightforward, they are fulfilled according to the rule, which is fixed to the ceiling with the help of two or three thin rails 10-15 cm longer than the height of the room (Fig. 47, c). Reiki is placed obliquely on the floor and first presses the ends of the rule with them, and then the middle of the rule with the additional rail. At the same time, the slats are slightly bent, springy and firmly press the rule to the ceiling. Rusting is carried out according to the rule, cutting through the rust. If the rust is not clean enough, it is fixed with a trowel. Sometimes a rust is carried out in a trowel with a small rack nailed to his canvas in the shape of a rust, after wetting everything with water. From this, rust becomes cleaner.

When repairing an apartment, one of the most difficult areas is the ceiling. Due to shrinkage of the house, subsidence or movement of soil between the ceilings, cracks of various depths form. It will not be possible to create a beautiful view of the interior with cracks in the ceiling, therefore, seams between the floor slabs will be sealed. The procedure is manual, but has a number of features.

Tools and materials

Sealing joints on the ceiling will require the preparation of tools and material. They should be prepared before the start of ceiling work with plates.

Flexible spatula with elastic blade

How to seal the seams on the ceiling between the plates? For this type of work requires:

• primer deep penetration better. The soil is intended to improve the adhesion of the concrete surface and the material with which it is planned to close the cracks;
• cement grade NTs, it is used to eliminate deep grooves. The main difference from the standard composition is the ability to expand and fill the holes during solidification;
• for wide gaps, a heat-insulating material is useful, the filler is construction foam, polyurethane or foamed polyethylene;
• putty with elastic material (latex);
• sealant;
• reinforced mesh with a width of 4-5 cm, if the width of the crack allows you to place the metal base inside;
• start and finish putties.

Processing the ceiling, as well as the floor, walls, you will need basic electrical appliances. The type of tool depends on the technology of sealing joints, usually enough:

• various sizes of spatulas;
• metal brush;
• spray gun;
• construction knife;
• hammer drill, easy to replace with a hammer with shock mode;
• sandpaper.

Before closing the joints of plates on the ceiling, you should take care of individual safety: eye protection glasses, a respirator, comfortable gloves and overalls.

How to remove the seams on the ceiling: preparatory stage

Before closing the seams on the ceiling, it is important to carry out the preparation of the coating. The surface should be solid, primed. Any coatings with poor fixation are best removed: old putty, paint, wallpaper, cement, lime, etc.

Sealing the joints of floor slabs is best done in a clean room (after wet cleaning). In order to achieve better adhesion and a normal course of mineralization of the working solution, the room must be dry. Soil is applied on top of the cleaned ceiling surface.

Before moving on to applying a subsequent coat, it is important to wait until the previous coat solidifies. The amount of time depends on the temperature and type of material.

Work with a wide shallow joint

If there are shallow cracks between the floor slabs with a width of 3 cm or more, it is better to use a filler, mounting foam.

How to seal the seam between the plates on the ceiling with foam? For this:

1. An assembly gun is introduced into the recess and the hole is filled with foam.
2. Foam is expected to dry, usually takes about 2-4 hours.
3. With a construction knife, all the protruding parts are removed, it is better to make a recess of several millimeters for better gripping, but the depth should not exceed 5 mm.
4. The recess is treated with elastic putty. It is convenient to use the material with 2 spatulas: narrow and wide. The mixture is stored on a wide tool, and the putty is applied with a narrow spatula.
5. Cover the seams on the ceiling with a wide spatula, removing excess and other defects.

Work with a wide joint of great depth

If you have to close the seam between the plates on the ceiling with a width of more than 3 cm and a relatively large depth, do not use foam.

Work algorithm:

1. Filling the recess with insulating material. Foamed polyethylene and polyurethane foam are suitable for the purpose.
2. Fixing insulation using sealant with maximum resistance to moisture.
3. After sealing the crack, the gap is sealed with SC cement, but a small groove with a depth of up to 5 mm is left.
4. After the cement has completely hardened, a latex type of putty is applied on top, and the plane of the plate is leveled with it.
5. With a spatula, remove the extra layer of preliminary putty and level out as much as possible.

Work with deep and narrow joints

It is better to close narrow but deep seams between the floor slabs using the same method as in the previous case.

How to seal the seams on the ceiling between the plates? The sequence of work is as follows:

1. A sealant is applied to a piece of insulation, it is placed inside the groove. The material should be pushed tightly into the recess.
2. After high-quality tamping, the insulation should leave about 1 cm of depth for applying cement to the SC. It is important to leave a 5 mm recess.
3. A latex putty is applied to the hardened cement mortar, it is leveled with a spatula.

Next steps

Sealing joints between panels does not end in the previous steps. It is important to perform the entire processing complex so that defects do not appear in the future. Otherwise, when the soil moves, the base of the building, the floor seams crack again, all the work will be futile.

The cause of cracks may be an incorrect calculation of the load on the structure or neglect of the construction technology, which makes the building shrink. It is important at the construction stage of the house to take into account the weight of the insulation of the house and to lay the water supply in advance to prevent the destruction of the bearing walls and the foundation later.

Protection of joints between floor slabs from destruction is carried out in stages:

1. Wait for the latex putty to solidify; complete drying takes about 2 days.
2. Preparing for reinforcing recesses. Apply the starting layer of putty, it is laid with a small protrusion beyond the edges by 4-5 cm.
3. A reinforcing mesh is pressed into the material, a roller or a narrow spatula will do.
4. A putty knife runs along the putty to remove excess.
5. After the material has hardened, it is necessary to treat the surface with sandpaper with fine or medium grain.
6. Repeated application of the starting putty will help to create an ideal plane, cleaning is performed with fine-grained sandpaper.
7. Top putty is applied.
8. After solidification, re-process with sandpaper.
9. The final stage is painting or pasting the ceiling.

Plastering

If in parallel with the destroyed seams on the ceiling there is a significant slope in any direction, it is worth aligning it. The best way is plaster compositions, their installation is preceded by the installation of the grid. The entire contact surface is covered with concrete contact primer, it contains solid, large particles to improve adhesion to concrete. To cover the ceiling, a composition of cement with gypsum is prepared.

Close up hole

Due to neglect of building codes, a marriage may appear on the ceiling, one of the most dangerous is a hole. The sealing of ceiling joints between the plates is performed by one of two methods.

First way:

1. Using an extended handle, the hole is cleaned from the inside.
2. It is important to remove loose dust, creating a strong grip, for this purpose thoroughly spray the entire surface with a spray gun.
3. Foam is blown inside.
4. After complete solidification, sections with excess material are cut with a sharp knife.
5. A recess in the shape of a cone with a height of 4-5 cm is cut out.
6. The recess is sealed with cement grade NTs and wait for the solidification of the material.
7. The surface is leveled with a layer of putty, and a mesh-sickle is laid inside.
8. Subsequent operations do not differ from sealing joints on the ceiling between the plates.

There is a second method of sealing joints of floor slabs with holes:

1. An improvised frame is created, which end-to-end fits in the hole, it is placed inside the defective area. You can use any metal wire.
2. The frame is fixed using sealant, it is better to use the one intended for the repair of plumbing and walls in wet rooms. If the purpose of the material is wet walls, a ceiling repair application often leads to a better result.
3. After solidification in the cavity, a lattice is obtained, it will provide a strong fixation of the solution.
4. A mixture of the SC solution is prepared, a classic composition can be used, but it is better to add an additive that will improve the setting of the solution. So that the cement does not fall, it is propped up from below with a piece of plywood.
5. The bottom plywood is fastened with a support, it will hold the cement in the required position until it dries.
6. The wooden shield is removed only after solidification, then the finishing is carried out.

The joint between the wall and the ceiling: methods of sealing

The presence of not only noticeable defects in the joints between the floor slabs, but also the walls is characteristic. Qualitatively finish the surface without eliminating cracks will not succeed.

• construction foam;
• gypsum mortar;
• synthetic putty;
• putty for outdoor use.

The simplest and most effective material is foam, which in the process of solidification expands and fills the voids.

If the joints are quite large, you should take care of further protection against cracking. A reinforcing mesh will help prevent the appearance of cracks, alternative materials - cotton, linen, which are impregnated in the adhesive solution. Fabrics are laid over the hole. At the final stage, a layer of plaster is laid.

What to do if joints are visible on the ceiling: final surface alignment

Regardless of how defects are removed, it is important to create a high-quality finish. To smooth the surface using abrasive mixtures.

To create a perfectly smooth and even surface, it is recommended to use non-woven fabric. It is glued to the ceiling to the finish layer of putty. The material helps to eliminate small bumps.

It is important to cover the ceiling with soil after the final leveling layer, this will help prevent the destruction of the coating and increase the durability of the putty layer. Now you can paint the ceiling, paste over or whiten.

The construction of the building and the creation of an attractive appearance is a complex task that requires taking into account many factors:

• creating a solid foundation will prevent cracks at the corners and between the floor slabs. Before that, it is important to carefully carry out preparatory work: investigation of the soil, studying the level of freezing of the soil, creating the correct layout and tamping of the surface. provides a life of up to 150 years only when following the laying technology;
• to save heat in the room, it is worth eliminating the leakage of thermal energy through the floor. One of the best ways is;
• in multi-storey buildings, it is better to first study the plan of floor slabs, this will help identify potential structural weaknesses and eliminate them during the repair phase;
• during the construction of housing it is better to use composite concrete, it is characterized by high technical characteristics and is absolutely safe for health;

• work with concrete in the cold season with the standard composition of cement is unacceptable by the manufacturer, but not all companies are ready to stop construction. Is it possible to pour concrete in winter? - Yes, but it will require the addition of special mixtures to the composition or electrical heating of concrete;
• if you plan to build a house from aerated concrete, be sure to reinforce every 2-3 rows. Lay reinforcement inside the block recesses, which creates a wall chaser for aerated concrete;

Holes of various dimensions can be sealed with proper observance of technology. It is recommended to choose one of the existing methods for eliminating ceiling defects, they are easy to use and durable.