Rusts are seams between floor slabs on the ceiling, which still adorn many apartments built during Soviet Union. At during finishing, sealing rusts helps get rid of this “decoration” and make the ceiling smooth and beautiful, since these seams can rarely fit into the interior of a modern room.

Materials and tools

For this we need:

— Gypsum plaster, preferably Rotband,
— Primer, several spatulas,
- Brush,
— A mixer for mixing the mortar, although for small amounts of work required, you can mix the plaster manually.

Before you start sealing the rust, you need to wash off the whitewash and clean it well. ceiling seams for good adhesion of the material to concrete base and, accordingly, long operation. We are talking about whitewashed ceilings because, as a rule, the painted bases have already been freed from rust during the preparatory work for painting the ceiling with acrylic paint.

Sealing technology

After the surface of the ceiling to be repaired is prepared, you can begin mixing the gypsum plaster, which should be of medium thickness and uniform mixing to complete the work, that is, without lumps and poorly mixed parts. You can knead right away plaster mixture for the entire room, since sealing rust is a relatively quick process, although labor-intensive.

After the solution is ready, we coat the ceiling rustics with a brush dipped in primer, carefully while doing this, making sure that there are no gaps. No need to soak the primer and immediately begin plastering. To do this, apply the solution to the seam in small strokes with an 8-12 cm spatula, and when the coated strip is a meter long, take a wide spatula and we remove excess gypsum plaster by moving along (!) the rust. There is no need to try to level the mixture by running a spatula across the seam of the floor slabs, as we will end up with a hole, which can then be visually visible.

In the course of this work, you can immediately straighten out large holes in the ceiling, if there are any, while filling up the rust, just do not forget to coat the required area with a primer before plastering, otherwise the solution may simply fall off due to poor adhesion.

Painting works

Further Painting works or sheathing around the perimeter with plasterboard can be carried out no earlier than one day after completion of the plastering, even if this gypsum plaster Rotband, which is believed to dry relatively quickly. Rotband sets quickly, but for completely dry he needs time and the moment of possible continuation of work will be clearly visible by the change in color of the plaster, which dries to light gray.

So, with the help of a simple repair operation, you can get rid of the latest “decorations” of the Soviet era, which, admittedly, were out of place and did not decorate the ceiling or the apartment as a whole, and for most residents were simply a source of additional irritation.

Questions and answers

Is it necessary to wet the rust before sealing?

Yes, definitely, otherwise the plaster may peel off, since there is a high probability that there is dust and dirt inside the seam - they interfere with normal adhesion.

Is the sealing done only along the rustication?

The final movement must be along, otherwise there will be holes in the seam. Apply Rotbunt or an analogue as you wish, but remove it along the line - this is mandatory.

Can I only use cement plaster for the job?

Not necessary - the rusts are indoors, so the gypsum mixture is perfect. It is optimal to use Rotband - it grips perfectly, is elastic and does not simply fall out of the rust.

P.S. Tips from the site Let's build together. Good luck with the renovation.

Rusts are artificially created grooves or rollers in plaster. For example, rustications are made on facades when cutting to look like natural stone, when plastering walls stairwells, when finishing ceilings mounted from prefabricated reinforced concrete flooring.

The tool used to cut through rustications is called rustication, or jointing. The simplest rustication is wooden template with a groove or roller cut out on the guide plane - this depends on the required shape of the rustication.

Professional builders, as a rule, have not used wooden rustications for a long time; they have been replaced by duralumin ones.

In my practice, I have improved this tool twice. First, on the basis of a wooden rustication, I created a more convenient universal one, which can be used to pull both a groove and a roller (Fig. 52). Here wooden platform size 240X 100 mm serves as a base 1. In the middle it is reinforced with a wooden vertical stand measuring 170x25x100 mm, which is additionally fastened to the base with two wooden struts with a diameter of 15 mm in cross-section. On one side of the rack, a metal plate with a protrusion is bolted 4, on the other, a plate having a semicircular groove 5. The first is used for opening the groove, the second is for pulling out the roller. The sides of the stand on which the cutting blades are attached are covered with metal strips. The dimensions of this rustication are 240x195x100 mm and it weighs no more than 250 g.

Rice. 52. Universal rustication for finishing grooves and rollers:
1 - base; 2 - rule; 3 - handles; 4 - steel plate for pulling out concave rustication (grooves); 5 - steel strip for pulling out convex rustication (rollers); 6 - screws

But this device is still cumbersome. And soon I abandoned it, making lighter rustications from duralumin - separately for each operation. The rustication at the ends of the metal strip has two protruding rollers for making a rustication groove (Fig. 53) or two similar plates, but with a semicircular groove on the working part. The rustication can also be used to install a guide rail.

Rice. 53. Rustication for making a groove

It is much more difficult to process rustications on ceilings. In modern industrial buildings reinforced concrete floors quite smooth. If the ceiling is the size of a room, then the plasterer has nothing to do here. If the ceiling is assembled from several reinforced concrete floorings, then there are seams between them that cannot be left unfinished.

It would seem that nothing could be simpler: fill the joint with mortar, rub it in better - and the job is done. However, this should not be done under any circumstances.

It will not be possible to hide the seam; there will be a sloppy stripe on the ceiling. Therefore, builders, on the contrary, emphasize the joint and embroider it. Only in this case it is necessary to ensure that the rustication is a clear and even line along its entire length. Achieve this without special devices very difficult. It was possible to develop such devices that began to be used everywhere. Telescopic stands included (Fig. 54), rustications, duralumin graters with foam and foam coating.

Rice. 54. Telescopic stand

The stand is used for mounting guide rails on the ceiling. It is made from duralumin pipes. You need two pipes with a diameter of 30 mm and a third of a smaller diameter - such that it can go inside the first two and connect them to each other. The top and connecting pipes have four holes through which the fastening pin is passed when it is necessary to extend the rack to a certain height. At the bottom of the rack there is a support heel, and at the top there is a screw jack with a clamping bar.

The rustication is a duralumin sheet measuring 270x70 mm. The edges of the canvas are bent upward - they slide along the guide rail. A handle is riveted in the middle of the blade, and slots are formed along the edges, semicircular steel knives with a radius of 8 mm are riveted into them. If the knife is positioned with the sphere facing down, it will cut the rust groove. In most cases, this is exactly the type of rustication that plasterers use.

The roller - a convex rustication instead of a groove - is pulled only in cases where the slabs for some reason turned out to be laid with some difference in horizontal plane. The groove is not suitable here, it only emphasizes the difference, and the roller will hide this defect.

Two workers are cutting the rust. They need two finishing tables, a stepladder, three telescopic stands, wooden slats, two boxes for solution, two brushes, two trowels, two duralumin graters with foam and foam rubber coating, rustication, darning, two buckets.

Work begins by marking the center lines of the rustications on opposite walls.

Then they make a notch on the edges of the slabs, clean them, moisten them with water, and if necessary, caulk the seams.

Fill the seam cement mortar(1:3), strained through a 1 mm sieve. The surface is rubbed first with a foam float and then with a foam float.

The next operation is to install the guide rail along the risks and secure it with telescopic stands. Two or three racks are sufficient for the entire length of the ceiling. The worker guides the rustication along the guide rail, the rustication rests against it with one side. Two knives at the ends of the rustication ensure greater straightness of the groove.

You need to remember: if you use cement mortar (1:3), then cutting through the rustication can only begin 1...2 hours after filling the seam.

This waste of time can be avoided. For this purpose, I began to use quick-setting gypsum cement mortar to fill the joint. For a bucket of water (10 l) you need to take 1 part of gypsum, 4...5 parts of dry cement mixture and 1000 g of polyvinyl acetate emulsion (PVA). The dry mixture and gypsum are mixed and filtered. The solution is prepared in small portions, per rust.

Using a brush, moisten the joint with water, to which PVA emulsion is added. Fill the seam with mortar and rub it with a foam or foam float. Strengthen the guide rail and immediately embroider the rust. There is no need for subsequent putty with this method.

It is necessary to say in conclusion about the method of decorating rustications on ceilings industrial buildings, where the height of the walls is significant - 3...10 m. You cannot install slats here.

As a rule, spherical slabs with protruding ribs are used for floors. These ribs can serve as guides for opening the seam between the joints of the slabs. In this case, a special rustication is needed - rackless (Fig. 55). It is also made from duralumin measuring 300X120 mm. One of the 40 mm wide sides is bent. In the middle part there are cutouts into which knives are attached. And here, by placing the necessary knives, you can cut a groove or pull a roller.

Rice. 55. Duralumin slatted rustications

It may happen that the floor slabs are laid unevenly, with differences. In this case, you will have to make a rustication, the shoulders of which have different heights. And not make a groove, but pull a roller.

They are laid with 15 mm seams, that is, almost end-to-end. Regulatory literature prescribes the construction of monolithic sections with reinforcement with a distance between slabs of 300 mm.

To seal the seams between floor slabs, you must use concrete with quick-hardening Portland cement or Portland cement grade M400 or higher with fine aggregate. The grain size of the aggregate should not be more than a third of the gap between the slabs and three-quarters of the clear size between the reinforcing bars. IN concrete mixture it is necessary to introduce plasticizers and setting accelerators.

If you get a standard seam between slabs with a width of 10-15 mm, then usually a reinforcement bar is laid at the bottom of the seam, which is arranged in the form of a “cone”, and filled with mortar.

We seal non-design joints up to 300 mm

If The width of the seams between adjacent slabs does not exceed 300 mm; sealing such a seam is relatively simple, there are several ways to fill the seams to choose from.

Method 1

At the bottom of the adjacent slabs, using spacers, we install a board or sheet of plywood that bridges the gap - this is formwork;
You can lay a piece of roofing material or film on top of the formwork, then there will be no traces of concrete left on the formwork, and it can continue to be used;
Fill the gap between the plates with mortar;
We wait for the concrete to gain strength within 3-4 weeks and remove the formwork.

Method 2

If it is not possible to bring the formwork from below, you can do permanent formwork made of galvanized roofing steel 0.8-1 mm thick according to the size of the gap between the plates, resting on the upper edge of the slab (trough). The profile of the side surface of the slabs will provide additional expansion and rigidity to the monolithic section.

Method 3

Another way to seal seams permanent formwork – from strips of steel with a thickness of 4 mm and a width of 5 cm, make mounting parts according to the gap profile, as in the previous case, resting on the front surface of the slabs, lay these mounting parts every 0.5 m along the length of the slab. On the bottom (in the plane of the lower edge of the slabs) we place a strip of galvanized roofing steel, plywood or plastic, and concrete it. This method ensures reliable adhesion of the monolithic section to the slabs.

Method 4

If you come across a pair of defective slabs with incorrectly positioned side locks, when the recess is at the bottom, they can be installed next to a gap of 2-3 cm. Place the formwork from below using method 1 and pour concrete through the provided gap.

Monolithic sections with a width of more than 300 mm

If the gap between the slabs is from 100 to 300 mm, we construct a monolith with reinforcement. Options are also possible here.

Option 1

Used when formwork from below is not possible.

We install load-bearing beams with a cross-section of 40x100 mm on the edge, in increments of 1 m, resting on adjacent slabs;
We attach the formwork panels to the load-bearing beams with wire twists;
Closing the formwork roofing material or film;
Install reinforcement cage on glasses so that the reinforcement is 30...50 mm above the formwork;
We are concreting.

Option 2

If it is possible to secure the formwork from below, it can be used for installation load-bearing structure fittings

We construct the formwork;
We make mounting parts from A1Ø8…12 reinforcement (depending on the width of the gap to be bridged), taking into account that there must be a distance of at least 30 mm between the bottom of the formwork and the reinforcement;
We lay protective material on the bottom of the formwork;
We install mounting parts;
We lay reinforcement or reinforcement cage;
We are concreting.

Do not agree to seal the gap between the wall and the slab with lightweight concrete cellular blocks(foam concrete, expanded clay concrete, etc.) - they do not have the required bearing capacity. Taking into account the arrangement of furniture along the walls, this section of the floor is subject to a large load, this will lead to the destruction of the blocks and the need for costly repairs of the floor.

The areas between the wall and the slab are sealed in the same way.

This story tells not only about sealing seams, but also about anchoring the slabs to each other:

Sealing the ceiling seam from the bottom side

Inter-tile seams - rustications are filled with concrete during installation, then the ceiling is primed, puttyed and painted, unless other finishing is provided.

Sequence of sealing rusts

Before concreting the seams are thoroughly cleaned of dust and mortar residues wire brush , for better adhesion of the solution to the slab, you can prime the side surfaces.

Cooked fresh concrete mortar unloaded into a container and delivered to the work site;
If the width of the rustication is small, the filling is carried out at one time, if the width of the area is large - in several layers, but no more than after 2...3 hours;
A concreting area of small width is bayoneted; if it is large, it is compacted with a vibrator;
For the first week, the surface of the monolith is moistened with water daily;
After 28 days, the formwork is removed.

Uneven shrinkage of the house

It's unpleasant when cracks appear on the ceiling. This often happens due to::

Uneven settlement of the building;
Incorrectly selected brand of concrete;
Poor quality concrete.

Let us dwell on the causes of uneven precipitation. It may occur in the following cases:

Structural defects - incorrectly designed foundation;
Foundation construction without taking into account geology, soil freezing depth and groundwater depth;
Poorly performed work on the construction of the foundation and masonry of walls;
Poor quality building materials.

To understand the reason for the appearance of cracks, it is sometimes necessary to order a construction inspection.

Decorative ceilings

A protective layer of concrete 30-50 mm thick should ensure that there are no rust stains on the ceiling from the reinforcement, but sometimes this layer is ineffective. From seeing stains on the ceiling, traces of leaks and rust cracks the best remedy– installation of a suspended, false or suspended ceiling.

Decorative ceiling – The best decision if necessary, level the ceiling surface. It will cover all construction flaws and give completeness to the interior. If you want to reduce the height of the room, arrange multi-level or dropped ceilings from plasterboard, acoustic boards or combinations of various materials.

In rooms of low height, false or suspended ceilings are used. The champion here is the suspended ceiling, which “eats” only 3-5 cm of the room’s height.

Every problem finds its solution. Sealing the seams between, even with large widths, does not pose a major structural or technical problem. From the proposed options it is easy to choose the one that suits your specific case.

/ What are ceiling rusts and how are they sealed?

What are ceiling rusts and how are they sealed?

IN modern house, such a problem as the non-parallel arrangement of floor slabs has long been solved. In houses old building, this moment could cause some inconvenience. Therefore, the builders left small depressions on the ceiling plane - rustications. In fact, rustics on the ceiling are a way to visually hide the unevenness of the slabs. But not everyone likes their presence and many are looking for ways to get rid of this not very beautiful detail.

How to get rid of them

There are two main ways to solve the problem of rust on the ceiling. Each of them has its own advantages and disadvantages, but which one to use cannot be determined immediately.

Layed floor slabs are not always parallel to each other. Height differences can be quite large. The choice of finishing method will depend on how strong the difference in the plane level of the slabs will be.

In one case, a whole range of works related to obtaining a smooth plane will be used. This option involves and is quite labor-intensive. Its undoubted advantage will be the most smooth and very even resulting plane of the new coating.

The disadvantages of this solution include a fairly large amount of leveling work and the high total cost of the work. In addition, not everyone can perform all operations with sufficient quality.

Sealing rust on the ceiling using the second method will be much easier. You just need to fill the existing recess with putty solution and bring the sealed area into the same plane as the rest of the ceiling. After this, it is necessary to sand the sealed area and give it its final look using finishing.

The costs will be much lower, and the amount of work will be significantly reduced. However, the employee’s qualifications will also have great importance. An inexperienced master will not be able to perform all operations perfectly.

Required tools and materials

Despite the general simplicity of the operation, you will need quite a lot of different instruments. An impressive volume of mixtures for leveling will also be required. Depending on how you decide to seal the rustics on the ceiling, not all items in the following two lists may be required.

Tool:

Rotary hammer with a special blade-shaped attachment
Hammer
Chisel for small work areas
Two spatulas - narrow and wide
Narrow brush for priming inner surface rusta
Drill with attachment for mixing mortar or construction mixer
Plaster beacons
Sandpaper for sanding the surface or a special grater

Materials:

Painting mesh or serpyanka
Polyurethane foam
Primer mixture or ready-made primer
Basic and finishing plaster

If all the items from the lists are already in stock, you can move on to the main work. But, even before the main work begins, it is necessary to prepare a bridgehead - the very premises where they are supposed to be carried out. It is necessary to carefully cover all pieces of furniture that could not be removed and protect the floor.

Order of Operations

Regardless of the chosen sealing option, you need to make several preparatory operations with the subject of work in order to be able to continue.

First you need to clean and expand the existing rustications. This is done with a chisel, a hammer drill with an attachment and continues until various materials stop falling out of the resulting crack. construction garbage. The rust needs to be expanded to approximately 3–5 centimeters. Small rusts can simply be cleaned with a spatula and the edges treated.

Next you need to carefully prime inner space rustication and the surface of the ceiling next to it. The primer will provide better adhesion to the materials that will be used for sealing.
After the soil dries, the surface inside the crack is wetted with water and filled polyurethane foam. The foam level should not reach the ceiling plane about 5 millimeters. After the foam has dried, it can be trimmed to the desired level.

The recess formed as a result of previous operations is re-primed and filled with putty. You need to apply it fairly tightly and without gaps.

When the putty has dried, a painting mesh or sickle tape is glued along the entire length of the seam. Final plastering is carried out on it, after which the finished surface is sanded.

The final stage is applying the finishing coat. This could be painting or wallpapering.

In the version using beacons, the operations will be identical to those that need to be performed when the ceiling is completely leveled. In this case, rusts are processed in the same way as all large defects during such leveling. The technology of work is no different from drawing a plane using beacons on the walls.

It should be noted that no matter which method is used, repairing rust on the ceiling is a very painstaking and difficult job. It is best to invite a specialist with sufficient experience in such work to perform such operations. Especially if you plan to align the plane with beacons.

If the differences in height or unevenness are more than 10 millimeters, experts recommend installing suspended or suspended ceilings. This option will be less expensive in most cases when the existing irregularities are large enough. And the installation of suspended ceilings will allow you not to repair any cracks at all and solve the problem in a minimum period of time, using the installers of the company from which the tension covering will be ordered.

The seams between floor slabs are among the ceiling defects that are difficult to repair. This happens because the slabs move among themselves both during the shrinkage of the building and during seasonal soil movements. Sometimes this displacement, invisible to the eye, causes complete destruction mortar filling the joints, and the seam appears again. Sealing with usual solutions helps only temporarily. Many people solve this problem with the help of suspended ceilings, but if the height of the room does not allow this, to complete the finishing it is necessary to seal the seams between the floor slabs on the ceiling.

Necessary materials

In order to properly and reliably putty the seams between the floor slabs, it is necessary to carry out preparatory work for jointing and sealing seams, as well as purchase necessary materials, having specific properties and suitable specifically for this purpose:

For deep seams, NTs grade cement is required, the peculiarity of which is that it expands during hardening, allowing it to densely fill deep seams and joints;
For a wide floor seam, it is necessary to use sealing materials made of foamed polyethylene or polystyrene, or polyurethane foam;
Primer deep penetration;
Putty with residual elasticity, for example, latex;
Serpyanka with a width of at least 20 cm;
Ceiling putty, preliminary and finishing;

Tools: narrow and wide spatulas, brush and spray bottle.

Technology of work execution

Floor seams are usually sealed simultaneously with ceiling repairs, so it is more convenient to carry out the preparatory work as a complex. The old coating is removed from the ceiling: whitewash or water-based paint moisten with water from a spray bottle, leave for 10-15 minutes and remove with a wide spatula to plaster. If the ceiling is covered with a thick layer of putty, it is cleaned only in those places where it has poor adhesion. If there are traces of rust on the ceiling, they are removed with special compounds. The seams between the slabs are opened: the old putty and plaster that are poorly secured in the joints are removed. If necessary, you can use a hammer drill. After processing, the seam should have a U-shaped or slightly expanded inward shape so that the putty holds better. Remove dust from the resulting seam by sweeping it away with a brush and wiping it with a damp sponge.
Inspect the resulting seam. If its width is more than 3 cm and its depth is small, it is sealed with polyurethane foam. To do this, lightly moisten the seam clean water and apply foam from a balloon. Wait for it to expand and begin to harden, after which the excess is removed, cutting it off with a knife so that a triangular-shaped depression with maximum depth 0.5 cm. If the seam is deep and not wide, it must be sealed with polystyrene foam, polyethylene foam or any other elastic material. The seam is pre-treated with a deep penetration primer and dried well. The seal is secured using a moisture-resistant sealant; the surface of the concrete must be dry. The sealant is placed deep into the slab, with outside The seam is sealed with NTs grade cement mortar so that a small depression remains at the joint. The cement mortar is dried.
Putty for rust with residual elasticity, for example, latex, is applied to the prepared recess with hardened mounting foam or cement mortar. Level it flush with the surface of the slab. It is convenient to put putty into the seam using two spatulas: apply to a wide one sufficient quantity putty, and put it narrowly into the seam, compacting and smoothing it inside the seam. After applying the putty to part of the seam, smooth it out with a wide spatula, removing excess.
The solution is dried for 24 hours and the joints are puttyed. Apply a layer of preliminary putty to the seam and adjacent surface of the floor slabs and glue sickle or paint mesh over it, pressing it into the layer of putty. Iron with a spatula along the direction of the seam. The width of the serpyanka or mesh must be at least 20 cm. Dry the putty and, after drying, level it with sandpaper. Apply another layer of preliminary putty with a finer grain to the entire ceiling, leveling it with a wide spatula. Dry and sandpaper. After this, apply a layer of smooth finishing putty, dry, level with fine sandpaper and paint.
If the floor slabs have a height difference of more than 1 cm, the ceiling will have to be plastered after sealing the seams. Plastering is done with a gypsum-based composition over a reinforcing painting mesh. The ceiling is treated with a special “concrete-contact” primer containing solid particles - it creates a rough layer on the surface of the slabs and facilitates the adhesion of the solution. The mesh is attached to a layer of plaster, carefully smoothing it out. After the plaster has completely dried for 2-3 days, you can begin to putty.

The ceiling made in this way looks absolutely smooth, there is no destruction of the seams, and the resulting microcracks, due to the plasticity of the putty, remain invisible. However, this method is unacceptable for apartments in new buildings - the house will settle within three to four years, and the slabs will inevitably move. Therefore, for new houses it is better to use other types of ceiling finishing, for example, suspended ceilings.