From reinforced concrete slabs There are seams between them. But now, with modern building materials seams between floor slabs and their sealing are no longer difficult, since the seam is easy to seal even in panel houses, where due to the low ceiling height it is impossible to mount dropped ceilings.

Sealing: preparation of seams

First of all, it is necessary to clean the seams between the floor slabs; to do this, they are cleaned with a steel brush or cut with chisels.

After this, the gap between the slabs must be filled with tow and sealed. At the same time, after compaction, the tow should not reach 15-20 cm from the front surface. If, for example, the ceiling was previously painted oil paint, chalk or lime whitewash, then it is necessary to clean it or wash it down to clean concrete. If the seams between the floor slabs were previously sealed with any material, it should also be removed if it does not hold firmly, peels or peels off. If old stuff It holds tightly in some places, there is no need to knock it down, let the seam sealing remain in place. Then you need to level the surface of the slabs on both sides of the seams, remove or knock down protrusions and other irregularities.

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The actual sealing of the seam

Dry tow can also be suitable for sealing the seams between the slabs, but it is better to first moisten it in liquid gypsum dough, which is prepared for this in small quantities. Thoroughly compact the tow. When hardening, the gypsum increases in volume and presses the tow even more tightly against the walls of the slabs.

Also, when sealing seams, you can use polyurethane foam, but this is the worst option. Suitable fillers include any mineral or polymer fillers, strips of drywall residues, mineral wool(if you use it, take precautions and protect your respiratory tract), polystyrene foam and even crumpled coated paper.

After this, the seams between the slabs must be carefully covered with a lime-gypsum solution of the consistency of sour cream, flush with the slabs. Then smooth them out and rub them in. To ensure that sedimentary cracks between the slabs are not so noticeable, rustling is performed to give the seam the required shape. You should not use acrylic primers, as they often cause worse quality adhesion of the plaster to the surface and the seal will not be strong. It is best to use putty or plaster.

Plaster is a dry gypsum mixture, often called coarse putty. When using plaster, a layer of up to 5 cm can be applied without reinforcement. And it is better to apply it with a trowel - a trowel, a trowel, because this tool is more accurate than a spatula, and is designed for applying plaster when leveling surfaces (the actual sealing).

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Methods for obtaining rustications

The first method is that the seams between the slabs are sealed using incompletely set mortar, which was previously rubbed, and the rustication is cut through with a special tool - a rustication tool. It is very easy to make a rustication yourself.

The second method is that the rust is pulled out over fresh, unset mortar using simple templates made from boards required width, cut on one side at an angle of 45°.

Rusts are made according to the rule, which must be fixed to the ceiling using 2-3 thin slats 15 cm long greater than the height of the room. The slats are installed obliquely on the floor and press the ends of the rule with them, and the additional rail serves as a support for the middle of the rule. The slats bend slightly, spring and press the rule very tightly against the ceiling. Rustication is carried out according to the rule, cutting through the rustication.

If the rust is not clean enough, it can be corrected with a trowel. In some cases, the rustication is carried out using a trowel with a strip nailed to the canvas. In this case, the rail should have a rustic shape. This is done to ensure that the rustics are straight. Everything is moistened with water in advance, which makes the rust cleaner.

If the rust is pulled out with a template, then this is done in several stages, applying a solution thin layer. After cutting or pulling, the rule is removed, then stripping and grouting is performed. The rust should be located exactly opposite the seams between the floor slabs.

Also, instead of lime-gypsum mortar, cement mortar can be used, but the execution process is delayed due to technical interruptions associated with the time required for the mortar to set.

Eliminating defects on the ceiling requires maximum patience and accuracy. For many, sealing ceiling seams is one of the most pressing problems during renovation: working under the ceiling is not very convenient, and the slightest irregularities are clearly visible even under a layer of plaster or wallpaper.

To begin with, the seam needs to be widened and cleared of finishing, then treated with a primer and, if necessary, filled with foam.

Most often, seams on the ceiling surface are formed between floor slabs, but sometimes the cause of their occurrence is improper fastening of decorative tiles.

It is more difficult to get rid of tile seams: to prevent cracks from appearing in the sealing areas, it is necessary to properly prepare the surface, use only quality materials and do not violate technology. At decorative finishing Much depends on the type of tile, but adherence to fastening technology is also important. It is much easier to make the ceiling seamless during finishing than to eliminate unevenness at the joints later.

Tools and materials

Interpanel seams must be properly processed before sealing, and for this you will need the following tools:

• putty knife;
• spray foam gun;
• perforator with nozzle;
• construction knife;
• not a wide brush.

The nozzle for the hammer drill should be in the form of a spatula, since this shape is most convenient for expanding the seam. If you don’t have a hammer drill, you can use a drill. It is better to choose a rubber spatula: it is more convenient to apply putty to the seams with a flexible blade. Before work, check the sharpness of the knife, because you will have to cut off excess polyurethane foam. In addition, to seal the seams you need the following materials:

• polyurethane foam;
• putty;
• primer;
• reinforcing mesh;
• PVA glue;
• sandpaper.

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Repair technology

To seal the seams as efficiently as possible, you need to completely clean them of exterior finishing, putty or plaster. Water will help facilitate this process: the section of the ceiling along the seam should be slightly moistened and the top layer should be allowed to soak. After 5-10 minutes, the plaster can be easily removed with a wide spatula. Then, using a hammer drill with an attachment, the seam between the slabs is expanded, and the remaining cement or filler is cleaned off with a knife. After removing debris and dust inner surface treated with a primer. For greater efficiency, use a primer deep penetration. You need to coat the seam very carefully so that the solution gets into every crack.

You might be interested in: Plasterboard ceiling installation

After the primer has dried, the seam on the ceiling is filled with polyurethane foam.

If the seams are not too deep, you can do without foam, replacing it with gypsum putty.

When the foam or putty has dried well, the surface should be leveled: excess foam is cut off with a knife, and the putty layer is rubbed with sandpaper. If there are no recesses left on the ceiling, you can proceed with further sealing.

Before sealing the seam, its surface is coated with a thin layer of PVA glue, onto which a reinforcing mesh is attached. It provides additional strength and reduces the possibility of small cracks along the joints of floor slabs. The edges of the mesh should overlap the seams by 2-3 centimeters. Now apply a layer of putty with a spatula and, pressing, carefully level it over the serpyanka so that there is no free space between it and the mounting foam.

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Final finishing

After filling the ceiling joints, proceed to finishing the entire ceiling to hide the joints of the ceiling and make the surface as smooth as possible. Take the primer mixture and evenly treat the ceiling in the room, paying special attention to corner areas and seams. The primer must dry completely; it is unacceptable to continue finishing on a wet surface. On final stage You will need a wide metal spatula and finishing putty.

A very thin and even layer of putty is distributed over the ceiling, making movements in one direction. If stripes or small sagging are formed during puttying, you need to wait until the surface is dry and treat it with fine-grained sandpaper. At this point, sealing the seams between the floor slabs is considered complete.

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Finishing joints on plasterboard ceilings

Suspended plasterboard ceilings also have joints. To eliminate them you will need:

• putty mixture;
• paper tape;
• primer;
• wide spatula;
• emery cloth;
• fiberglass painting mesh.

You might be interested in: Installation of plasterboard ceiling

A thin layer of putty mixture is applied to the seams, covering 2-3 centimeters of the sheet surface on both sides. The seam is closed at the top paper tape, and then another layer of solution, removing the excess with a spatula. The dried joints are sanded and primed, and then a painting mesh is secured to the ceiling using push pins or a stapler. Dilute the putty again and cover the ceiling with it, rubbing the mixture well over the mesh. All excess is removed with a spatula so that ceiling surface was as smooth as possible. After letting the ceiling dry, they do another sanding and priming, and then paint.

If you are a resident last floor V apartment building, then this task will become somewhat more complicated for you. You will definitely need to check the roof for integrity, otherwise there is a high risk of flooding.

Where to start if the apartment is on the top floor?

Let's start our article with the most complex and expensive option.

So, if your apartment is located directly under the roof, then before you start sealing the cracks inside, it would be a good idea to see what’s going on on the roof.

This is very important, because if seams appear, then it is very possible that outside there is some damage. And if these “holes” are not patched up, then your joint putty will last until the first good rain.

Fortunately, most high-rise buildings have soft roof, covered with roofing felt. It's quite inexpensive, so better time It will cost money, but you can do everything for sure.

Of course, you are unlikely to get by here on your own. Not even because of labor intensity, but because laying roofing felt requires special heating tools. Where did a simple, albeit very homely person, get them from?

You don't need a lot of material. Place the sheets in the place where you can definitely see that the coating is worn out and cracked.

And after you decide main problem from above, you can take on renovations inside the apartment.

What materials and tools should I purchase?

To seal seams, you do not need to buy something very expensive. What is usually available on the farm will be sufficient:

• A regular spray bottle to moisten the ceiling and soften old putty
• Paint brushes for applying primer
• Construction knife for cutting dried foam
• A metal brush, for thoroughly cleaning the gap from the remains of old filler
• A good, convenient spatula for finishing coating putty
• A couple of cans of polyurethane foam (if the gaps are more than 2 cm, and they usually are never smaller)
• A little cement primer (this will ensure good adhesion of the materials)
• A roll of reinforcing mesh (choose the width depending on the size of the seam, so that it extends beyond it by approximately 5 millimeters)
• Starting and finishing putties

Here, in general, is all the inventory.

Now let's take a step-by-step look at how to seal the gap with your own hands.

Where do you start sealing cracks?

First of all, you need to thoroughly clean the surface. Even if the gap is very small in appearance, the ceiling next to it must be cleaned very well with a spatula. Most likely, as you remove the layer of putty, you will see life size a gap that may not be small at all.

You need to completely clear the gap from old, dried out mortar. When building a house, the cracks are filled with ordinary cement, but over time it loses its strength: rains, temperature changes, and again shrinkage... It is advisable not to leave a single extra pebble or piece of cement, since it will not allow it to “set well” later. new material.

After you have completed this work, we move on to another stage, also preparatory.

We clean the entire ceiling from old putty and prime it

Yes, you will now have to start cleaning the rest of the surface. If you want the end result to be a smooth and decent ceiling, then don’t even dream that you can “patch it up” partially.

First, try using a spatula to dryly chip off the old putty. If it comes off well, then continue, step by step.

If she doesn’t want to lag behind, you will have to thoroughly wet the ceiling warm water and wait until the coating softens somewhat.

Don’t think that the putty will actually soften, it’s not whitewash. But still, it will become a little more pliable and it will be easier for you to deal with it.

After you complete this most disgusting and time-consuming process, pick up a wire brush and thoroughly scrub everything clean. And the ceiling surface and cracks.

Then dilute the primer in the same way as it is written on the package and thoroughly “walk” along the ceiling. In principle, the primer is already sold in liquid form and is diluted solely for the purpose of economy.

If you don’t want to save money, then you don’t even have to breed. After all, primer is very inexpensive.

When you complete this procedure, leave the ceiling for five to six hours to dry completely. There is no need to rush, even if the ceiling looks completely dry. Do not forget that the primer penetrates deep into the concrete and you simply cannot see that it is damp inside.

And this moisture will not allow the materials to “grab” well.

What and how to cover the seams on the ceiling?

Well, we've reached the most important thing. We mentioned polyurethane foam above. This is the best and easiest option today. There is no point in fiddling with the solution if such an ingenious thing is on sale.

The spray nozzle on the packages is very thin and you can easily destroy any hole. Don't forget to shake it well!

And don’t press the sprayer too hard, it “goes” just fine. If you overdo it and press down too hard, a huge ball will instantly appear and simply fall to the floor.

Keep in mind that the foam expands several times, so don’t try to fill it in as much as possible.

The foam dries in about a day. When it hardens, you need to take a special construction knife and carefully cut off the remains. Try to remove it as evenly as possible so that it does not protrude even a millimeter beyond the edges of the seams.

The penultimate touch: sticker of the reinforcing mesh

For some reason, painting mesh cut into strips is called “serpyanka”. As a rule, she has adhesive layer. Therefore, you can stick it directly onto the gap, and then apply the starting layer of putty.

If your serpyanka is not adhesive, but regular, then you need to take a spatula, apply the first layer of putty, and put a mesh on it, while it is still wet.

Gently press it with a spatula, achieving the most even plane possible.

Be sure to let this layer dry! If you rush and start applying a second coat, the mesh will move and you will have to remove everything and start again.

When the first layer has dried, apply a second layer of putty to the reinforced gap. The main thing is to try to make these layers thin, remembering that you need to level them with the entire ceiling.

In a day or two, when the gap is completely dry, you can begin to putty the rest of the ceiling.

How to seal cracks in other rooms?

In principle, the essence of the work does not change much from changing places. If the floors in your garage have also come apart, you can repeat the procedure completely. This must be done to prevent water from leaking onto your beloved car.

There are also gaps on a concrete balcony or loggia. Here the cracks are much more voluminous and it is inconvenient to seal them simply with foam. If the hole is large, use pieces of polystyrene foam, but pour foam into the gap between it and the concrete.

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.

1. Cooked fresh concrete mortar unloaded into a container and delivered to the work site;
2. 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;
3. A concreting area of ​​small width is bayoneted; if it is large, it is compacted with a vibrator;
4. For the first week, the surface of the monolith is moistened with water daily;
5. 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- a device for hanging, hemming or stretch 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, multi-level or suspended ceilings made of plasterboard, acoustic boards, or combinations of various materials are arranged.

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.

Any renovation in an apartment starts from the ceiling. In panel houses, a phenomenon such as cracks is often observed. They most often appear at the joints of concrete ceilings. No matter how you whiten the ceiling, they will come back again, reminding you of the incorrectly performed repairs. The question arises of how to seal the seams between the slabs on the ceiling.

What tools will we need?

To seal cracks between concrete slabs will come in handy:

• gypsum dry putty;
• deep penetration primer;
• spatula with a flexible elastic blade;
• hammer drill or drill;
• a spade attachment for a drill;
• drill mixer;
• masking tape;
• PVA glue;
• fine-grained sandpaper / sanding mesh;
• acrylic sealant;
• sealant gun.

Sequence of work execution

Repairing a seam is quite a labor-intensive job that must be done scrupulously, otherwise bad job It will be visible no matter how you paint or whitewash it. Haste in this matter is a big hindrance.

The sequence is as follows:

1. Instead of foam, you can use ceramic tile adhesive to seal deep cracks.
2. A painting mesh can be successfully replaced by ordinary gauze or a bandage. Will also work thin cloth, which is pre-soaked in water and steamed with an iron so that the fabric does not shrink afterwards.
3. To avoid much hassle with leveling the ceiling, you can cover it with seamless polystyrene foam tiles.
4. Small seams are sealed with joint compound or acrylic sealant. Silicone sealant We do not recommend using it because paint does not stick to it.
5. Another idea from folk craftsmen is simultaneous reinforcement and filling of cracks. This is done as follows: mix thick cement mortar with the addition of a small amount liquid glass, dip a piece of bandage into it, roll it into a tourniquet and put it in the gap. You need to act quickly - the solution with glass dries very quickly. Use the same solution to level the ceiling and, after drying, sand it with sandpaper.
6. Be careful in areas where there might be wiring, otherwise you may damage it with the drill and create more work for yourself.

Conclusion

Perfect sealing of cracks is necessary if you plan to subsequently whitewash or paint the ceiling. But there’s no point in worrying too much about leveling if you plan to decorate the ceiling tension structure or hanging systems. For a stretch ceiling, absolutely no ceiling preparation is required. Just clear the ceiling construction waste, the remains of plaster or whitewash, so that later they do not fall onto the film from the inside. However, it is still worth sealing the deep gaps between the floor slabs.