Why and how expansion joints are made in concrete: an overview of the technology, types of joints and a step-by-step scheme of work. Expansion joints of concrete floors Grinding drywall butt joints

How well you cope with such a task as sealing drywall joints depends on the stability of the future structure and its appearance. If the seam is processed incorrectly, then over time:

• cracks or a small mesh of them will appear in this place;
• the service life will be much reduced;
• The topcoat will be damaged, and this, of course, will entail additional spending of money.

And if the sealing of drywall seams will be carried out using technology and using high-quality materials, then you will never have to spend your family budget on reworking the final repairs in the apartment.

Drywall joints can be processed in many ways. We will tell you the most popular and correct ones. Those that are carried out according to approved technological processes, in accordance with GOSTs, methods and building rules. A list of them is given at the end of the article.

It doesn't matter if you need to seal the joints of drywall, which is mounted on a metal frame, or glued to a flat wall. It's important to follow the process.

Conditions for the production of works on the sealing of butt joints

In order to save the money earned, effort and time, several requirements should be fulfilled before starting work:

1. The surface to be treated must be cleaned.
2. The width of the reinforcing tape must correspond to the dimensions of the seam.
3. All fastener heads should be sunk into the sheet so that they do not protrude.
4. GKL on the surface, and even more so at the joints, should not have delamination. The presence of such a flaw suggests that you need to cut the paper to the very base and carefully sand this place with an emery cloth.
5. Check the reliability of the fastening of the sheets and the quality of the installation of the frame.
6. Create a favorable indoor climate:

• humidity should be normal, since in other conditions the gypsum board will change its linear dimensions;
• the temperature should be maintained at least + 10 ° С, and this indicator must be kept for the entire period of operation and for the drying time of the finishing putty (in winter, temperature indicators should be in the range of +13 - +20 ° С);
• drafts, sudden heating of the room or cooling are unacceptable during the work process.

Sealing seams with serpyanka

Fiberglass mesh, professionals call it serpyanka, is made with an adhesive layer. It is intended for sealing butt joints of plasterboard sheets, gluing seams, cracks on repaired surfaces. Serpyanka absorbs moisture well. After interaction with the putty and final drying, it gives a single strong reinforced surface.

The grid characteristics are shown in this table.

Consider how to seal up the seams on a plasterboard structure with your own hands using a fiberglass mesh. Needless to say, the surface must be free not only of dirt, but also of dust. The microclimate in the room should not be disturbed. The process itself will consist of the following stages:

1. Joining of seams.
2. Priming of joints.
3. Surface putty.
4. Fiberglass mesh sticker.
5. Re-putty.
6. Grinding of butt joints.
7. Cleaning the surface from dirt and dust.

End joints for any type of sealing of seams must be chamfered. For this purpose, a special device is used - an edge plane. This tool will chamfer at an angle of 22.5 about 2/3 of the sheet thickness, which is quite enough for this type of work. Using a plane is much more convenient, and the process is much faster.

It is also permissible to use a knife in this procedure. True, he removes a chamfer at an angle of 45 degrees. But this is quite enough for high-quality performance, only you need to work more carefully and not rush. It doesn't matter what you cut - what tool you have, so work.

It is imperative to chamfer the drywall cut. This will be needed so that the putty can be laid in the resulting depression. This procedure will significantly strengthen the structure of the partition or wall.

If you do not do this, then when puttying on the cut you will get a tubercle, which will have to be leveled with a thicker layer of finishing putty. And this will lead to a greater expenditure of building material and a rise in the cost of work. If the layer is thin, then during operation the seam will crack, since the technology for sealing drywall seams was initially violated.

The slightest deviation from technology leads to the formation of cracks on the surface of the finish and entails unforeseen costs in impressive amounts.

Experienced specialists in such circumstances say that the miser pays twice. And, unfortunately, in practice, this is a very common case of a technology breach.

Priming joints

Now you should start priming the joints. For this we need a special composition bearing the same name. You can buy it at specialized stores. The primer is well absorbed into the material, an invisible film is formed, which has excellent bonding properties, adheres to surfaces. This water-soluble mixture permeates only the top layer of drywall and does not penetrate inside.

In the process of subsequent surface treatment, the cardboard itself will draw water from the solution or glue, thereby deteriorating the quality of adhesion of the material. And the primer layer will prevent this process, since the film does not allow moisture to pass through, does not allow dust to enter the surface to be treated, and even has antifungal components.

The layer thickness must be at least 0.03 mm, and it can be applied:

• with an ordinary brush;
• maklovitsa - a special brush;
• roller;
• garden spray.

For convenience, the solution can be poured into a cuvette. And if the volume of the primer container used is small, use it by dipping the brush directly into it.

Manufacturers offer us three types of primer:

1. Phenolic mixture. Mainly applicable for working with wood and metal. But it can also be used as the first layer of soil for a plasterboard structure.
2. Alkyd mixture. Not suitable for drywall. This composition causes deformation of the cardboard layer of the sheet. The paper peels off, and bubbles are obtained, which then burst, hanging on the surface in rags. It is clear that there is no need to talk about any durability of a clean finish.
3. Acrylic (universal) mixture. Ideal for drywall, used both before and after filling.

Pay attention when choosing a primer mixture for one of the parameters - it should be for interior work. The facade mixture contains harmful substances that are prohibited for use in residential premises.

GKL, treated with a special primer mixture, lasts longer, does not lose its aesthetic appearance and properties. In addition, the putty on the primed plane lays down more evenly.

Putty seams

This kind of work is required to level the surface. According to our method, we will do this twice, then the joint between the sheets will become even, smooth and with good adhesion properties.

For work, we need a dry or powdery putty. It is diluted strictly according to the instructions before being applied to the surface. You cannot procure the composition for future use in large volumes - it dries quickly and you will have to throw away unclaimed material, as it will become unusable for work.

There are some subtleties here. If you dilute the mixture in large quantities, for example, you will process a large surface area and you have a lot of workers, then using a construction mixer for mixing, do not use high speeds. This method involves a lot of additional air in the composition, and its excessive amount has a bad effect on the strength of the final product.

If you are diluting a small volume, then pour dry powder into water until islands form on the surface of the water and stir gently. The color of the putty can be beige or gray. This indicator does not affect the strength of the material in any way.

Two spatulas are required for work:

• wide (25-30 cm),
• narrow (7-8 cm).

A layer of putty is applied to the joint with a narrow spatula in such a way that the composition can penetrate deeply, you can drown it a little - press it into the seam. In this case, you should not feel sorry for the solution, but you also do not need to show fanaticism. The remains can not be removed for now, because the mesh will then be glued to them. Surplus will be removed at another stage of work.

Do not forget about the places on the drywall where the screw caps are screwed in - they also need to be putty.

Processing the joint with fiberglass mesh

After applying the putty solution to the joint, apply the tape to the joint. It is better to measure it by length in advance, or you can do it during work, but this is when there is an assistant nearby. Serpyanka is well cut with scissors. Using a spatula, press it tightly along its entire length to the joint.

Apply the tape strictly in the center of the seam. If one piece runs out, overlap the next and continue.

Using a wide spatula, go over the surface to be treated again and at the same time remove excess putty. Now it takes time for the joints to dry.

Second layer of putty

The top coat can be applied to joints when the surface is dry. To do this, you will need to wait 8 to 12 hours. The second pass will remove all the flaws that were skipped earlier and make the seam stronger.

It is necessary to achieve a minimum covering layer so that the joint cannot be determined by eye.

But if this did not work out, there is the next stage in the technology of work.

Grinding drywall butt joints

Grinding of the areas we need is done with ordinary sandpaper, an abrasive mesh, which are fixed on a special block, or with a special abrasive float. What to choose - decide for yourself.

Sandpaper is not very convenient to work with, but you can stuff it on a block - and then it will become much more convenient to work. Sandpaper during operation is constantly clogged with dust, so you have to constantly clean it. You can buy material in the store in rolls or cut into pieces. An important indicator for the purchase of this product is grain size. You can start work with P100-P180, this is a larger option, and finish with P 220-P280.

The abrasive mesh has a perforated structure and most of the dust passes through the holes. It is attached to special holders; the nets can be changed at your discretion. The shops sell it already cut into pieces. It is convenient to work with such a tool, however, it costs a little more than sandpaper.

Think not only of the material, but also of yourself. The work you want to do with your own hands now is very dusty. Therefore, you will need:

• respirator;
• gloves;
• special glasses;
• protective clothing.

The room must have good lighting, otherwise you will not be able to see the defects that need to be corrected.

If there are no practical skills in this process, first try sanding the joint in a small area. This is done in a circular motion. Capture a small area at the same time and control the pressure. If scratches appear on the surface, change the material number to a smaller one or reduce the pressure. After the work has been done, all dust and dirt will need to be removed.

Performing work using this technology, you will get an alternation of layers: putty, serpyanka, putty. This combination is made according to the approved technology and gives a good effect. The joint is flush with the surface of the sheet and is difficult to determine by touch.

Sealing drywall seams with perforated paper tape

Now let's look at how to seal the butt joints on the gypsum board using perforated paper tape. In principle, the technology is the same as described above. Having a clean surface and observing the permissible indoor climate, you have to complete the following steps:

1. Sew the seams.
2. Prime the joints.
3. Spackle them.
4. Stick on perforated paper tape.
5. Apply a top coat of putty.
6. Grind butt joints.
7. Clean the surface from dirt and dust.

The implementation of the first, second and third points is carried out using the same technology as described in the section "", so the information specified there will be useful for this type of joint processing. But let's stop at the fourth point and talk about this material in more detail.

Processing the joint with perforated paper tape

This material is a strip of paper with:

• micro-holes, they prevent the tape from swelling and bubbling;
• a marking line in the middle, which serves for convenience and simplification of the workflow, especially for finishing the interior corners of rooms.

Perforated paper tape for drywall prevents cracks at the joints of the sheets. Its physical and chemical properties are identical to drywall; it reacts to any changes in temperature and humidity in the same way as it does. This means that deformation in the seams treated with this material is excluded.

The paper tape is presented to the consumer in rolls, width 52 mm, sold in lengths of 50, 76 and 153 m. An environmentally friendly material that is produced on the basis of cellulose. It is made of extra strong paper, longitudinally and transversely reinforced with fiberglass. Its surface is slightly rough to the touch. This helps in better adhesion to the putty.

The internal structure with the presence of microscopic holes does not allow air inclusions to form during operation. If you tear off a small piece from the paper tape, you can see how long its fibers are. This means that it holds a high load on rupture.

True, it is worth considering that the tape should fit snugly enough on the layer of putty to the seam, not have bends and bubbles. Therefore, the putty solution should not be thick at all. You can also avoid the appearance of bubbles with micro-perforated tape.

According to the technology, a tape that has been previously soaked in water should be sculpted at the joints with cut edges. The process is more laborious than with a serpyanka, the installation method differs from the mentioned technology and has some nuances.

The tape itself is not self-adhesive, which means it is applied to the putty layer. Pre-soak the measured pieces in boiling water for five minutes. Take out one and squeeze out excess water. To do this, the material must be passed between the thumb and forefinger of either hand, thereby removing excess moisture from it.

Adjust the tape to the center of the joint and press lightly into the putty in a taut position. Adjacent ends should overlap. Gently pass along the tape with a spatula - from the center to both ends alternately.

Effort should be applied to ensure proper adhesion, but do not overdo it so as not to squeeze the layer of putty from under the tape. A layer of 1.5-2 mm should remain under its middle part, 0.8 mm under the edges. Now you can remove the excess mortar along the longitudinal edges with a spatula.

Then you need to wait until the joints dry, putty them a second time and leave again for 8-12 hours. Do not forget - the necessary microclimate must be observed in the room.

After the seams are dry, you need to sand their surface. How to do this and what is described in the section "", in the sub-item "".

The need to perform these works

The work described above, of course, is laborious, and they have to spend a certain amount of the family budget. But nothing can be done. After all, the putty of drywall seams is as necessary as a metal profile and its high-quality installation.

Forgetting to putty the seam or deciding to save money at this preparatory stage, one day you will find a small crack in your apartment, which will increase in size. No matter how rigidly the frame is installed and the sheets are not securely fastened, under the influence of vibrations, unforeseen shocks, the joints of the gypsum board will "play". That will certainly lead to their cracking and loss of dried putty, since the owner did not use the reinforcing tape.

Violation of any of the existing technologies leads to poor-quality work performance, and subsequently to a shorter service life of all materials involved. Which is fraught with additional costs of money and time.

Topic of the article: What can be used to reinforce the joints of sheet materials

(reinforcing tape plus putty for finishing the joints) must ensure the joint strength is the same as the drywall panel itself. Otherwise, normal deformations in the structure of the walls or ceiling can cause cracks at the joints of gypsum plasterboard panels. Thus, the quality of the work on sealing the joints of the gypsum board depends largely on the choice of reinforcing tape and putty.
In this review, we will not consider all kinds of putty options, but focus on the tape. In the practice of dry construction in recent years, for the purpose of sealing flat joints, two main types of tape have been used: self-adhesive construction tape ( mesh) and perforated paper tape. Accordingly, the question arises: what is the difference and what to prefer? To begin with, we will consider each separately.

Paper tape.

The paper tape is sold in rolls 52 mm wide, 50.76 m or 153 m long. Of those brands that are heard, you can name Sheetrock, Knauf, NextBuild.
The paper tape is made of special extra strong paper reinforced with fiberglass in the longitudinal and transverse directions. Its surface is slightly rough for better adhesion to the putty. The tape has a slight depression in the center, which makes it easy to use for finishing inside corners. The paper tape effectively resists stretching and creasing.
The disadvantages of paper tape include the installation process, which is somewhat more laborious in comparison with the serpyanka, and (with insufficient qualifications of the worker) the tendency to form air bubbles with a small amount of putty under the tape (more on this below). To avoid bubbles, it is better to use a tape with microperforation, which reduces the likelihood of bubbles and at the same time does not affect the strength characteristics of the tape.

Serpyanka is self-adhesive.

Serpyanka is sold in rolls 45 and 50 mm wide, 20, 45 and 90 m long. It is usually used for finishing joints of plasterboard sheets with a thinned edge, as well as for sealing cracks and small holes. There are many brands that are distinguished by tensile strength. The nets are also divided into two types: self-adhesive and non-self-adhesive. The latter is less expensive, but more laborious (requires fastening with paper clips).
One important detail: when using self-adhesive tape, the started roll must always be stored in plastic wrap to prevent the adhesive layer from drying out.
Fiberglass tape, unlike paper tape, for obvious reasons is not recommended for reinforcing inner corners.

Now let's look at how to work with each type of tape.

The method of sealing joints using a serpyanka.

Longitudinal joints of drywall with a thinned edge can be recommended to be reinforced with a self-adhesive serpyanka (mesh). It is easier to use and requires less labor time. Plus, you don't have to worry about air bubbles or delamination (which sometimes happens with paper tape).
The disadvantages of this method are (Attention !) lower strength of serpyanka in comparison with paper tape, as well as the need to select a suitable type of putty for application.
When using a serpyanka, it is recommended to first mount it on all joints of the room, firmly pressing the mesh to the previously dust-free surface in order to avoid the formation of wrinkles. Then you need to apply the putty over and into the depth of the mesh with a spatula along the entire length of the mesh, preferably in a thin and even layer

Method of sealing joints using paper tape.

As mentioned earlier, fiberglass mesh works well at the longitudinal joints of sheets of gypsum board with a thinned edge. But for the reinforcement of transverse joints, it is not strong enough. Such places require special strength and only paper tape can reduce the risk of cracking here (the main problem of joints). Unlike fiberglass mesh, paper tape forms an extremely strong joint when used with any type of joint filler. However, the procedure for installing paper tape differs from the technology for installing fiberglass mesh and has some subtleties.
Since the paper tape is not self-adhesive, you first need to apply a thin and relatively even layer of putty to the joint for gluing the tape. In this case, you do not need to try to cover all the joints of the room with putty at once, since it can begin to dry out before you reach the last joint with the tape. This, in turn, will lead to a more complicated workflow and to the formation of air bubbles under the belt.

It is recommended to finish the joints one by one, especially in the absence of sufficient skills and, accordingly, a low speed of work. Then you need to adjust the tape in the center of the joint and, keeping it taut, slightly press it into the putty, while the ends of the tape should overlap. After that, "stretch" the glued tape with a spatula.
This is usually done from the center of the joint and alternately at both ends. It is important to apply enough pressure to properly adhere the tape, but at the same time it should be enough to squeeze out only excess filler and leave a layer 1.5-2.0 mm thick under the middle of the tape and about 0.8 mm under the edges. No need to try to squeeze out as much putty as possible - the tape will have nothing to stick to. After the tape is glued evenly, tightly and without wrinkles, you need to remove the excess putty along the longitudinal edges of the tape with a spatula.

Further work is the same for both options.

And finally, a quote: « Multiple tests for the strength of reinforced joints have shown that joints finished with conventional fiberglass mesh (serpyanka) and conventional joint filler are more prone to cracking than joints finished with paper tape and similar filler. This is because the fiberglass mesh (serpianka) tends to stretch under load, even when covered with putty. Overhaul of such cracks is difficult. Therefore, it is not recommended to use regular fiberglass mesh for finishing drywall joints in most cases. "

so , summary

Paper tape is the most "ancient" and traditional material for reinforcing drywall joints, recommended by gypsum board manufacturers and at the same time the most reliable and still unsurpassed in strength.
The choice of the most reliable reinforcement system is especially relevant for climates with large seasonal fluctuations in temperature and humidity as a preventive measure against cracking.

As you know, the seams at the joints of drywall should not be inferior in strength to the drywall itself. Otherwise, with temperature and other deformations of drywall, cracks may appear at the seams, which will nullify all the work done. In this article I will tell you in what ways you can seal the joints at the seams of drywall, and how to do it preferable.

In the past few years, when reinforcing drywall seams, builders have mainly used 2 types of materials - a reinforcing self-adhesive mesh "serpyanka", a spider web glued to the glue, or construction paper tape with perforation. Both of these options are quite common and have slight differences in the installation method, as well as have different quality. Let's take a look at both options, and I'll explain why paper tape is preferred.

Option one, using a serpyanka for reinforcing the seam

We use a self-adhesive serpyanka, glue it on the joint of drywall sheets along the entire length.

We breed plasterboard putty, it is better not to save on it and purchase plaster putty from well-known manufacturers, for example Knauf.

We put the putty on a wide trowel and putty the seam with the mesh, I prefer to work in several steps, making the widest possible layer of mortar.

The wider the seam is smeared, the less it will protrude on the wall and the less it will be visible in the end. Therefore, do not strive to make narrow seams, as thick as a tape or slightly wider, the normal width is 10-15cm.

When dry, the seam is ready. However, although the mesh method is the simplest, it has its drawback - the lack of a safety margin. Due to its qualities, the reinforcing mesh can stretch in one direction or another in the wake of the drywall, which will lead to the appearance of cracks in the seam in the future. Repairing such seams is quite laborious, and if the room is exposed to temperature effects or moisture, the choice in favor of a reinforcing mesh, serpyanka is not the best.

Here a few words should be said about drywall, or rather about its edge. At the moment, almost all good drywall has a thinned PLUK edge, this is the optimal type of edge.

The rounded edge leaves a lot of space for putty, which has a positive effect on the readability of the seam.
However, if the sheet originally went without an edge, or you had to cut off a piece, you need to recreate such an edge. This can be done either with a special edging or with an ordinary knife (with caution).

Option two, the use of reinforcing paper tape

Drywall paper tape is not ordinary paper tape. Firstly, it is reinforced with fiberglass, but secondly, a high-quality tape has microperforation, which allows air bubbles to escape from under the tape, and thereby create a better-quality seam. It is such a tape that is preferable to use when reinforcing seams. In general, the paper tape is stronger in comparison with the mesh and holds normal loads when drywall moves from humidity and temperature changes, which avoids cracks at the seams.
Since the paper tape does not have an adhesive layer, first putty is applied directly to the seam, then the tape is glued, and a finishing layer of putty is applied on top.

We apply the putty in the same way as when using the mesh, evenly filling the seam.

We glue the tape on a layer of putty, try to fix the tape in the center of the seam. We iron the tape for gluing and release of bubbles. It is important that the extra putty goes away, but the necessary one does not come out. This can only be understood with experience.

We close the tape with a finishing layer of putty. Do not overdo it, the layer should be thin so as not to form a bump on the wall.
This completes the reinforcement of the joint. Not much more difficult than using a grid, but much more reliable.

How to patch up a corner joint

Often they make all sorts of complex structures from drywall. Here a metal profile for drywall, putty and paper tape will come to the rescue.
Especially as an example, I will show on this small piece of drywall by the window how this is done. We mark the holes for the profile and fasten it to the drywall.

We also go through one side of the joint with a putty knife, covering the profile, then do the same with the other side.

We glue the paper tape to the putty.

We go through a layer of putty from above, trying to make the most even transition from the sheet to the edge of the metal corner, you can try to completely close it with putty.

That's all, the corner is ready. For reliability, at the end of the repair, it is necessary to glue a plastic protective corner so that the putty does not crumble from accidental blows. Here's another good one.
This concludes my story, I tried to talk in detail about how you can seal the seams on drywall, explained why it is better to use paper tape and not mesh. The choice of which technology to use in your repair is always yours. Thanks for watching and good luck with the repair!

What is required in order to correctly, quickly and beautifully reinforce drywall seams, internal and external corners? To begin with, you should not use such a serpentine for this.

Even with a little effort, it crawls. No quality can be expected from her. Better to use seam paper.

It has an inflection point, and this is the place where you need to place it along the drywall seam.

It is not necessary to use PVA glue, fill the paper, use the universal Sheetrock putty. The manufacturer believes that such a putty is quite enough and you can do only with it.

For the outer and inner corners, we will use special paper-based corners from the same manufacturer Sheetrock.

Here is an outside corner with this profile.

Here is the inner corner.

There is clearly less metal here, good perforation is noticeable at all corners. Perforation is necessary so that air bubbles come out, and some amount of putty will come out through it. The corners themselves are 3.05 meters high, from which you can cut pieces of the desired size. Let's start with paper, show how to use it, apply it correctly, so that everything is competent and beautiful. KNAUF drywall itself, 12.5 mm thick, ordinary, not waterproof, GKL-PLUK 12.5X1200X2500.

If we immediately apply Sheetrock and try to stick a piece of paper, then a lot of putty will remain in the depths, no matter how we squeeze it out.

Gradually, the paper in this place will get wet and warped, increase in size and take on an unsightly appearance, creating difficulties for subsequent work.

Therefore, it is better to use UNIFLOT to work with these seams. This is such a putty, which sets very quickly, after 20-25 minutes it can already be sanded. First you need to putty the depth of the seam with UNIFLOT, go through with a spatula, and after 20 minutes you can put a piece of paper here on Sheetrock. All the work will be done in one day.

So, to work along the seam, you need paper and a spatula of different widths.

With each subsequent layer of putty, you need to switch to the next size trowel. A wide spatula can be used for the final filling of the joint.

We hammer UNIFLOT into the seam.

There is a factory chamfer on the sheet, it is very long, you do not need to hammer all of it, since paper should still be located in this place. Therefore, we hammer only the very depth. You can take a narrow spatula, for example, 5 cm wide, and remove all unnecessary things so that the putty remains only in the groove.

Now we will show how to reinforce the inner corners. We will use for this such a small comb-type spatula.

These corners do not require any preparation. They have a metal part to which the Sheetrock will not stick.

The metal will only reinforce the corner, and the Sheetrock will sit on the piece of paper itself. Therefore, if there are any gaps, they can not be repaired, but left as they are. A gap 3-4 mm wide is not scary at all, its preliminary sealing is not required. It is enough to make several strokes of Sheetrock with light movements. You don't have to do it beautifully. The faster the better.

Then we carry it out several times with a comb spatula.

Sheetrock is applied evenly, there are practically no empty spots. We take a corner, put it in its place, run it with a spatula, squeeze out the excess.

If the corner is three meters long, it is better to apply a little Sheetrock to the spatula. When we lead with a spatula, he will immediately smooth this piece of paper and create a small layer on top. A few movements - and the corner is reinforced.

Now you need to wait until it dries, take a larger spatula and putty the corner itself again. It's easy, simple and quick to do.

Outside corners are good because they don't require any preliminary filler. Apply a little putty. It is not necessary to level it too much.

We pass with a comb spatula. The corner is now completely ready for installation.

We set the angle, orient it along the plane, press it on one side. You can put in some Sheetrock.

The putty is squeezed out from under the paper, the corners themselves are of high quality, the paper does not get wet, does not increase in size, and does not form folds on it. If Sheetrock is under a metal, it cannot have any effect on that metal and on paper. Therefore, here you can proceed as follows. Do not wait long, but immediately apply some more Sheetrock and remove it in one stroke.

We leave the seam in this position until it dries completely. Irregularities, dimples do not need to try to align immediately. One pass is quite enough, you still have to go 2-3 times to the outer and inner corners, and to the seams.

About half an hour has passed, UNIFLOT has dried up, there are no wet spots, nothing is scratched. It is not required to sand with emery, you can immediately apply paper. Take Sheetrock, fill in the groove.

We take a piece of paper, put it with a curved place inward so that the tubercle does not stick out.

Slowly squeeze out the entire Sheetrock from there. A little slip putty can be applied to the spatula.

You can move on to the next step. Since there is very little putty left under the paper, the paper will not get wet and warp. We immediately remove the excess putty from the edges and leave it to dry. Only after the Sheetrock is dry can you proceed to the following steps.

Another 2-3 hours passed. Before completely filling the entire wall, you need to go through this seam again with a wide spatula.

If there are small irregularities left, they will overlap the Sheetrock when we putty the entire wall. This is how it happens in reality with the full dimensions of the corners:

We managed to work without any complicated devices, bazookas and other things, working according to the “spatula technology”. This did not significantly affect the quality of work, in the end, everything can be compensated for by experience.

All video rights belong to: Alexander Perikov

Concrete bases are the most durable, reliable and strongest. However, concrete is a capricious material in the formation of structures, surfaces and their operation. Loads acting on the material and in the material, which have different causes, lead to cracking of the monolithic surface. This happens if you do not take timely measures to create compensation cuts that prevent such phenomena.

What is an expansion joint?

This is a purposeful fragmentation of the concrete base (floor, wall, roof, etc.), which weakens the action of external and internal forces (stresses) leading to uncontrolled deformation and destruction of the concrete monolith to its entire depth. Such deformations can lead to a decrease in the performance of buildings. The expansion cut reacts and dampens changes in geometry, consisting of several independent fragments. Such seams are a serious factor in ensuring the reliability and durability of structures.

The need for a device

Structural elements of buildings are connected and constantly interact with each other against the background of the fact that buildings change their geometric dimensions under the influence of changes in the temperature and humidity conditions of operation, frame shrinkage, precipitation of hardening concrete monoliths. All this causes stresses in the nodes of a single structure of a structure, although often such changes in the geometry of elements are visually imperceptible. The creation of cuts contributes to the even distribution of additional loads (forces, stresses) by compensating for changes in the geometric dimensions (expansion, compression, twisting, shearing, bending, etc.) of the material that have arisen due to factors acting on concrete (or in concrete).

Loads always affect structures, but without formed expansion joints, they entail deterioration of the characteristics of foundations, the occurrence of cracks, manifestations of structural deformations, an increase in internal stresses, a reduction in the duration of operation, etc. For example, heating / cooling of walls leads to a slight change in their dimensions, which in turn creates stress in the material. The larger the dimensions of the walls, the larger and more stress.

They cause cracking (in, interior decoration), are transmitted through a rigidly connected frame to floors, beams, stairs, foundations, etc. A minimal shift in the position of the wall in the stress source will immediately threaten the integrity of the rigid structure of the building. The duration of the impacts, their magnitudes can even cause the destruction of the structure of the structure. Movements and seasonal heaving of soils also manifest themselves as a factor in the destruction of the blind area, if temperature sections are not provided for in them.

What are expansion joints?

Types and purpose of joints in concrete.

The nature of the loads that must compensate for the sections is the main feature of their classification. They are subdivided into stationary (conventionally) - technological and shrinkage, as well as sedimentary, insulating and temperature, deformation. Interruptions in work with concrete are accompanied by the formation of technological breaks, when the cushion of material, cast earlier, adjoins the face of a new section of the monolith.

Shrinkage cuts, by fragmenting the slab, weaken tensile stresses in the hardening material, which facilitates the passage of cracks below the cut without reaching its surface or the passage of a fracture along the seam. They also compensate for deformation in case of uneven moisture loss in different areas of the screed. Buildings are divided into sections by external temperature sections, which protects against deformations caused by changes in concrete temperature.

Often they are combined with seams, the task of which is to compensate for vertical shifts in certain parts of structures due to uneven settlement of soils under the building. Expansion joints relieve assembly joints of structural elements from twisting deformations, transverse and longitudinal stresses. They are formed at the junctions of the floor to the columns, flights of stairs, curb stones, on the fractures of the planes of the material, areas of the stepped difference in the height of the screeds, etc.

Insulation joints are necessarily created at the junction of the floor with walls, stairs, columns, etc. Their task is to suppress the transfer of deformations (temperature, shrinkage, etc.) from the structure frame to the floor screed. This separation prevents the passage of shock sound waves inside the premises through the screed and back. Expansion joints are formed to compensate for the movement of soil and buildings relative to the blind area. Its fragmentation and elastic connection to the foundation provide damping of loads.

How are they performed?

There are two methods of forming seams using diamond or abrasive wheels:

• assembly - when at the stage it is divided into fragments using damping materials (glass, timber, polymer tapes, plastic lining, etc.) laid to the entire depth of the slab, which can be removed from the seam or remain in it;
• cutting - when the hardening concrete slab is cut to a fixed depth, and the formed seams are sealed with polymer sealants, mastics, closed with special structures or left unfilled. The step (strip width) of the cut is determined as follows: the screed height (in cm) is multiplied by a factor of "24". The result is the step of arranging the seams (in cm).

They are made perfectly straight, their intersection is allowed only at right angles. At the same time, the cut joints should not form the letter "T" in the plan. When it is impossible to exclude in the plan the intersection of the seams in the form of a triangle, the figure is made equilateral. The minimum joint width is 0.6 cm, which depends on the height of the artificial stone layer. can be carried out as early as 12 - 72 hours after laying (depending on the air temperature), however, the situation should be excluded when the concrete is completely dry and the cut edge of the material crumbles.

The depth of the sections is 1/4 - 1/2 of the slab height. Indoor floor area is considered indivisible (up to 30 m2) when the aspect ratio of such a "rectangle" is not more than 1: 1.5. Large areas are divided by shrinkage seams into similar or smaller areas. When a monolith has a length of 25 m or more, it must be crossed with seams. If the tracks of the hardening material are 3 meters wide or more, longitudinal seams are made.

On slabs open for precipitation, cuts are made with a step of 3 m, and the maximum area of ​​a single piece is no more than 9 m2. Monoliths of paths (corridors) are cut with transverse seams with a step of up to 6 m (the usual step is twice the width of the material laying), and L-shaped turns are fragmented into rectangles (squares). Also, the slots separate the floor coverings from various materials, the bases in the premises along the doorways, the places where the height of the screeds changes.

Such seams, like those that turn out to be under, are not filled, but are sealed in the open air. The sections of the floor slabs encircling the columns should be squares in plan, the corners of which are located opposite the flat edges of the columns (the square formed by the seams rotates 45 degrees relative to the edges of the column). The structural integrity of the dissected bases is ensured by special systems placed in or applied to the seams. These are metal profiles and seals.

In the blind areas, the wall seams are filled with roofing material, bitumen or sealant. subdivided into sections of 2 - 2.5 meters, which are intersected by seams (perpendicular to the wall) to the entire depth of concrete pouring. Such a separator is formed by a board (fixed formwork), laid on the edge so that its upper edge coincides with the formwork surface. Boards (up to 3 cm thick) are treated with hot bitumen, septic tank. Also, special vinyl tapes with a thickness of up to 15 mm are used. Then the formwork is concreted.