Lay floor slabs with gas silicate blocks. Floor slabs for aerated concrete houses

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The question of how to carry out the installation of floor slabs becomes relevant during the construction of any room. At first glance, it may seem that installation is quite simple, but there are some nuances that need to be considered when building and erecting a building.

Floor slabs are reinforced concrete products designed for arranging interfloor ceilings.

To understand how to lay the slabs, you need to know the technology and rules for laying floor slabs. Reinforced concrete structures can be divided as follows:

• round-hollow ceilings;
• tented (ribbed);
• long ribbed.

Some people prefer to use monolithic reinforced concrete slabs during construction, but this option is more expensive. The most common types that are used for floors are reinforced concrete round-hollow. They have good thermal conductivity, sound insulation.

Floor slab installation technology

For installation, you must have:

• round-hollow reinforced concrete slabs;
• truck crane;
• cement mortar (cement, water, sand);
• Master OK;
• grinders or autogen;
• sledgehammers;
• level;
• scrap;
• steel brush;
• tow;
• gypsum mortar;
• lime-gypsum mortar;
• thermal insulation material;
• welding machine.

This is not to say that the installation of floor slabs is an easy process; on the contrary, it is considered quite time-consuming and risky.

Any foundation is not even and smooth, therefore, before installing reinforced concrete floor slabs, it would be correct and expedient to make the foundation even, for example, lay out a row of bricks on a concrete base. To check how even the surface is, you can use the level, level. It is possible to lay floor slabs only on the most even surface, the further service life of the entire building depends on this.

It is necessary to take care of the strength of the foundation, because due to heaving of the soil, its deformation can occur, and no matter how responsibly the builders approach the installation and how the floor slabs are laid, the building will squint over time.

The foundation can be fixed with a conventional reinforced mesh, on which concrete mortar is subsequently applied and floor slabs are installed. Cement must be at least grade 100. The height of the cement layer must be at least 20 cm.

Before installing reinforced concrete floor slabs, you need to prepare them.

If there are flaws, protrusions or chips on the surface, they must be eliminated.

To understand how to lay the slabs, before installing and installing reinforced concrete floor structures, you need to calculate the width so that they occupy the entire perimeter and do not leave uncovered parts. The calculation scheme is quite simple.

Before the installation process, a substrate of concrete mixture is laid out. Laying floor slabs is possible only with the help of a truck crane, since their weight is large enough. Having hooked reinforced concrete slabs on the hinges, they are lifted and placed in the right place. Moreover, it will not work to carry out the laying alone; for this process, a team of 3-5 people is needed. When installing, it is necessary to ensure that each plate lies flat, all elements should be as close as possible to each other. Due to the fact that the cement footboard does not harden immediately, the plates will be movable for some time, and installation inaccuracies can be corrected by correcting them with a crowbar.

It is necessary to lay floor slabs only on the main walls of the future premises. Installation of internal partitions and walls is carried out after the installation of floor slabs, and they must rest on the wall by 12 cm. Adjacent slabs must be attached to each other with mounting loops. For laying, it is better to use a cement-sand mortar, it must be liquid, the sand is carefully sifted, otherwise even if small debris gets in, it can lead to deformation of the floor and ceiling.

After the installation of the floor slabs, there are seams between them that must be sealed. Using a steel brush, all seams must be cleaned. The gaps between the elements of the reinforced concrete structure are filled with tow, pre-moistened in a gypsum solution. The tow layer must be compacted. When the gypsum mixture dries, its volume increases, so the tow will press against the walls as much as possible. After that, the gaps are covered with lime-gypsum mortar.

The ends present also need to be sealed so that the plates do not freeze during the cold season.

To do this, you can use mineral wool, concrete mortar or backing bricks.

In any construction process, force majeure situations can occur, for example, slabs can burst if unloading rules are violated or they were stored incorrectly.

But throwing away such expensive building material is impractical. They can be installed on 3 main walls. Or they can carry out the installation of the attic, in this place the load is minimal.

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Laying floor slabs: important points

For the accuracy of the design, you need to draw a diagram with all sizes, so you can avoid gaps and lack of plates. If there are still large gaps, they can be filled with cinder block, and small gaps and cracks can be filled with concrete mortar.

When installing hollow core slabs, care must be taken to ensure that they are laid with the smooth side down. They should be located as close to each other as possible - even the smallest gaps should be avoided. You need to lay them, adjusting to each other along the bottom edge.

When installing floor slabs on a foundation base, it is very important to know that they should only be installed on 2 walls, and with short, not long sides. This method of installation is needed in order to prevent possible deformation and displacement if the foundation “sags”.

The thing is that in such cases, the entire weight of the structure moves to the third, long side, and cracks or gaps may appear on the short sides, and this cannot be allowed. Also, one should not forget that the short sides of reinforced concrete blanks should not be fully installed on the walls - by 11-15 cm. This will help reduce heat loss in the further operation of any room.

You should immediately think about where the communications will take place in order to leave gaps between the floor slabs for them.

After the installation of reinforced concrete structures, it is imperative to tie them with reinforcing bars for the strength and strength of the future premises. For this, rods with a diameter of 9-12 mm are suitable, you can use class A1 wire rod (when loads arise, it will stretch and not break). The rods are welded at one end to the loop, and the other end to the loop of the adjacent floor blank. It is impossible to connect several reinforced concrete slabs at once - only two slabs are interconnected. From the outside, the plates are fixed with anchors.

Be sure to pay attention to the rules of transportation, unloading and storage of reinforced concrete structures and materials so that they do not undergo deformation. Between reinforced concrete slabs, wooden beams must be placed at the same distance and in the same places, otherwise they may burst under load.

In some cases, when reinforced concrete slabs are in the cold for a long time, they can freeze, then due to the moisture that will be in reinforced concrete structures, fungus and mold can form. To avoid this, you need to make small holes in each blank at a distance of 25 cm from each other and blow mounting foam into them. Thus, reinforced concrete structures will not absorb moisture.

They are usually made from prefabricated reinforced concrete slabs. There are several types of reinforced concrete floor slabs: cellular concrete, multi-hollow heavy concrete and prefabricated monolithic floors. They are selected based on the span width and bearing capacity.

Hollow-core floor slabs PK and PNO, with a bearing capacity of 800 kgf / m2, have found the greatest application.
Distinctive features of such floors are high strength, fire resistance, manufacturability and complete factory readiness for installation.
Ceilings from multi-hollow reinforced concrete slabs are used with a step of load-bearing walls up to 9 meters. These floors are durable, fire-resistant, provide the necessary spatial rigidity and stability of a residential building.
The slabs are laid closely and connected to each other by embedding the seams between them with cement mortar. To create a rigid single horizontal floor, reinforced concrete slabs are connected to each other and to the outer walls using steel anchors fixed to mounting loops. The gaps between the slabs, when resting on the internal walls, are filled with bricks of the same brand as in the main masonry.

When using a concrete floor, a prerequisite is the installation of an annular reinforced belt.

In modern literature, you can find several ways to construct an annular reinforced belt. (Arm belt):

So in one case when the wall is made of lightweight aerated concrete and the support of the slab does not reach 250 mm. (usual support - 120 mm), use a distribution belt, through which the floor slabs rest on the wall (Fig. 1). Such a belt is carried out for the entire length of the floor support on the wall and can be made of monolithic reinforced concrete or from three rows of solid brick reinforced with masonry mesh. The width of the belt is 250 mm and the thickness is at least 120 mm. The floor slabs must rest on the distribution belt at least 120 mm. Together with floor slabs, it creates a rigid structure to increase resistance to wind loads, temperature and shrinkage deformations, as well as stability in case of emergency impacts..

Rice. one. Knot for supporting the floor slab on the wall
from cellular concrete gas silicate and foam concrete blocks.
1 - masonry; 2 - thermal insulation layer; 3 - leveling layer of cement-sand mortar; 4 - floor; 5 - floor slab; 6 - monolithic reinforced concrete belt; 7 - additional masonry blocks; 8 - prefabricated reinforced concrete lintel of the window opening; 9 - fiberglass corner; 10 - slope; 11-elastic gasket; 12 - window block

In the second case: when the compressive load passes the established norms or the width of the support of the slab on aerated concrete blocks is more than 120 mm, the distribution belt can be omitted. In this case, its role in giving the house a rigid structure is played by an armored belt in the form of an annular anchor along the outer perimeter of all laid floor slabs. Photo. №2 -5

Good afternoon.

It is very good that the foundation is intact. And we have 90% of subscribers build houses themselves. Therefore, you have come to the right place.

But I want to upset you, you can’t put slabs on blocks. I'll explain why. You will understand for yourself that these are completely different things - an armored belt and masonry from blocks or a lintel above the window. The armored belt can easily perform the function of a jumper above the window. So now many people are building, immediately above the window they drive out the armored belt, then 2-3 rows of blocks with good density and a slab on top. It is possible to lay slabs on nasosilicate only if the density of the block is 1600. But you will not find such blocks. Even if your house were made of bricks, you would still need armored belts, since they perform the function of evenly distributing the load. A brick or block perceives a point load on each brick. Concrete and block masonry have different strength characteristics and if you check them for compression, the block is very soft and brittle. In the reinforced belt, the reinforcement lies tightly, is clamped by concrete, and the strength and stability of the enclosing structure is determined precisely by the reinforcement.

An armored belt is a well-reinforced concrete layer that is laid along all load-bearing walls, necessarily closed and in no case interrupted. Designed to increase the strength of load-bearing walls and maintain structural integrity during subsidence, temperature fluctuations, precipitation or soil shifts.

Armopoyas is especially necessary when building a house from blocks (gas silicate, Varmit, aerated concrete, etc.), since these materials do not have good resistance to bending loads. Armopoyas takes on all the load arising from the deformation of the structure, evenly distributes the load on the foundation and the rest of the masonry. From the floor slabs and the roof, the structure experiences the strongest vertical loads that only the armored belt structure can cope with. Therefore, if you do not want the masonry to disperse, you need to do it as expected.

For your building, you will need 2 armored belts, under the floors between the 1st and 2nd floors and under the roof of the house along all load-bearing walls (we also take into account internal ones).

Armo-belt parameters: monolithic belt with a minimum height of 20 cm, and a width in the thickness of the block. It is advisable to immediately calculate the insulation for your region from gas silicate 400 mm, you can tell us about this and specialist Valeria will calculate just a block or you need to insulate it from the outside.

Reinforcement of the armored belt: 4 rods of longitudinal reinforcement Ø12 mm, laid in 2 rows (2 rods in each row), connected by transverse reinforcement (clamps) Ø8 mm with a step of 30 cm. Reinforcement indent from the edge of concrete - 5 cm. Scheme:

Are you going to clad the house or plaster?

Ask what is not clear.

According to the material of manufacture, the plates are divided into:

• reinforced concrete;
• aerated concrete.

Reinforced concrete hollow core slabs

This is the most popular and affordable type of plates.

Previously, the use of massive reinforced concrete floors was not available in the construction of a private house due to their high cost and heavy weight, requiring the use of special equipment for delivery and lifting. Now there are no such problems, and a crane or manipulator has become commonplace in low-rise construction.

Hollow-core reinforced concrete slabs have additional relief in the form of through holes-chambers, and they themselves are made of heavy concrete grades with reinforcement, which provides the necessary rigidity and strength. Such an overlap has a number of undeniable advantages:

• Ease of construction in comparison with a monolithic slab; voids significantly reduce the weight of the product, which means that they can be safely used in aerated concrete buildings up to 3 floors inclusive.
• High strength, which is provided by internal cavities, reinforcement and high-quality concrete. The bearing capacity of plates of this type is from 800 kg/m 2 .
• Simplified installation and the ability to mount on bases of any shape. The size of the slab can be 6 and 9 meters, which significantly expands the possibilities for planning.
• Internal cavities can be used to accommodate communications and wiring.
• Good soundproofing.

The device of reinforced concrete floors will require around the entire perimeter. It can be made monolithic using formwork and reinforcement with a thickness of 10 mm or more. The width of the belt is not less than 150 mm - the distance on which the plate will rest. Due to this, the load on the walls is reduced, local stresses caused by the pressure of the upper floor and the slab itself are eliminated.

Marking

According to the configuration of the cavities, the plates are divided into:

• PC - with round voids, rests on 2 sides;
• PCT - with round cavities, based on 3 sides;
• PKK - with round voids, fits on 4 walls;
• PKT - with round cavities, mounting on 2 end and 1 long side;
• PG - with pear-shaped voids; thickness - 260 mm; support on 2 ends;
• PB - made without formwork, by continuous molding; its thickness is 260 mm, the hole diameter is 159 mm; the product is placed on 2 end sides.

According to the size of the cavities and the thickness of the plate, they are divided into the following types:

solid single layer:

• 1P - plates 120 mm thick.
• 2P - plates 160 mm thick;

multi-hollow:

• 1pc - slabs 220 mm thick with round voids 159 mm in diameter.
• 2pcs - slabs 220 mm thick with round voids 140 mm in diameter.
• PB - slabs with a thickness of 220 mm of bee-formwork molding.

Slabs of types 2P and 2PK are made only from heavy concrete.

Dimensions

The size of the hollow slab is included in its marking.

For example, PC 90.15-8. This is a round-hollow slab 90 decimeters long and 15 dm wide. Permissible load on the ceiling is 8 MPa (800 kgf/m2).

Under the spoiler are the standard dimensions of the plates. To view, click on the heading "Table".

Support depth

It is important not to exceed the maximum support depth. Otherwise, the slab will work as a lever, and under heavy loads, a slight lifting of the wall above the slab is possible. It is not noticeable to the eye, but critical to the structure. Under loads from installed furniture, equipment and erected internal interior partitions, cracks may appear in the walls from the resulting stresses.

The length of support (the depth of insertion of plates into the walls) should not exceed:

• for brick walls - 160 mm;
• when supporting floor slabs on aerated concrete blocks of class B3.5-B7.5 - 200 mm;
• when resting on a concrete armored belt - 120 mm.

The minimum support length is also normalized. It should not be less than:

• 80 mm - for brick walls;
• 100 mm - for walls made of cellular concrete blocks;
• 65 mm - when resting on dense concrete of class B10 and above.

Installation of reinforced concrete floors will necessarily require the use of a crane or a manipulator with a large lifting capacity. The weight of a standard 6-meter slab reaches 2 tons. In addition, installation will require certain skills. So alignment is carried out at the seams on the smooth side of the ceiling, after which the plates are fastened with anchors, and the joints are poured with cement mortar. Mineral wool, foam plastic can be used as a heater.

Aerated concrete slabs

Not only are made of foamed concrete, but also interfloor partitions. This material has good strength, low thermal conductivity, it is easy to process and easy to use. Aerated concrete slab can withstand a load of 300 to 600 kg / m 2, and the maximum weight does not exceed 750 kg. The accuracy with which such a ceiling is made allows installation in a short time and does not require additional preparation for subsequent finishing. These are the lightest floor slabs for aerated concrete walls.

Now on the market you can find two types of such structures:

• They are made of concrete by autoclave injection molding, equipped with special elements of the tongue-and-groove type, which simplifies installation. With this method, the density can correspond to the concrete grade D500. This option is most in demand in low-rise construction.
• Standard panels, reinforced with reinforcing elements, can be used in any monolithic construction. Easily processed, inexpensive, well suited for non-standard solutions.

The maximum size of aerated concrete slabs does not exceed 5980 by 625 mm, and the thickness can be from 150 to 300 mm. Minimum length 2980 mm, pitch 300 mm. Such a variety of sizes and low weight makes it easy and with minimal loss to close the space between floors or any complex shape.

The slab should rest with its edges on the wall of the house by at least 10 cm, so the layout must be made taking into account this size.

The disadvantages of such an overlap follow of the features of the most cellular concrete, therefore, the choice must be approached carefully and after careful calculations of the bearing load and operating conditions.

• Aerated concrete is a very fragile material, which is practically devoid of elasticity. To avoid cracks in walls and ceilings, it is necessary to take care of a high-quality monolithic or well-buried foundation, which excludes any ground movements.
• This material perfectly absorbs moisture, and this will require additional waterproofing with a special primer in areas such as bathrooms and toilets. Reinforcement in the composition of aerated concrete must be processed in accordance with the requirements of SN 277-80, which guarantees the service life of the floors at least 25 years.
• The bearing capacity of less than 600 kg/m 2 is insufficient to accommodate heavy furniture and equipment and a large number of people. Screed, flooring, underfloor heating systems reduce the already low load capacity.
• Additional reinforced concrete beams will be required, laid through a distance in the width of the slab.

Comparative cost

When constructing interfloor structures, the issue of price plays an important role. If we compare all varieties with each other, we get the following sequence. Reinforced concrete hollow slab will be the cheapest with a cost per square meter of 1200 rubles. In second place will be a monolithic product - 2000 - 2500 rubles per square meter. The cost can vary greatly depending on the thickness and manufacturing technology.

The most expensive floor is a foam concrete slab - from 3,000 rubles per square. The high cost is due to the complex manufacturing technology and the small width of the plate.

Also, the cost of a slab ceiling should include the costs of transportation and lifting, which in some cases may be equal to their cost.

Currently, in our country, the most popular are three methods of building floors in the house. This is the installation of floor slabs, the device of a monolithic reinforced concrete floor and the device of flooring on wooden (less often metal) beams. We will definitely talk about all these methods and not only. And the first technology that we will consider is the installation of finished floor slabs.

First, a little about the floor slabs themselves. Depending on their shape, all plates can be divided into flat and ribbed. Flat, in turn, are divided into solid and hollow. We are now interested in void ones, because it is this type of slabs that is used mainly in low-rise construction.

Hollow core slabs, in turn, are also classified according to various parameters, such as the shape and size of the voids, the thickness of the slabs, the manufacturing technology of the slabs, and the method of reinforcement.

I will not delve into the topic of classification. It is better to look for this information on the websites of enterprises producing reinforced concrete products (reinforced concrete products). We'd better talk directly about the installation.

The very first point that you need to pay attention to even at the design stage of your future home is the opportunity to purchase in your area exactly the slabs of the sizes that are laid down in the project. Each manufacturer has its own specific range of manufactured products and it is always limited. This is really important and it surprises me that very often developers forget about this recommendation and then they have to either cut one or more slabs or make a monolithic section on the floor. We'll talk more about this below.

Storage of floor slabs at the construction site.

Of course, it's great if you have the opportunity to lay floor slabs immediately upon delivery, directly from the machine that brought them. But most of the time this doesn't happen. Or the driver insists that you unload the plates as quickly as possible, because. he is in a hurry for the next order, or the plates are not laid on the machine in the order you need, or you just bought them in advance and are not going to lay them yet. In all these cases, the plates will need to be stored on your site.

Try to choose a flat surface for this. Never lay tiles directly on the ground. Be sure to put something under the edges of the slab, for example, trimming a wooden beam. There should be only two linings, at a distance of about 25-40 cm from the edges. Linings cannot be placed under the middle of the plate.

Boards can be stacked up to 2.5 meters high. Make the linings under the first slab higher so that in the event of their possible indentation into the ground when laying subsequent slabs, the first one in no case touches the ground, otherwise it can easily break. It is enough to make all subsequent linings even from an inch (2.5 cm). They must be stacked strictly on top of each other.

Preparation for installation of floor slabs.

Preparation begins even at the moment when the masons kick out the last rows of masonry. The slabs will lie flat and without drops if the upper rows of load-bearing walls are even and lie in the same horizontal plane.

To achieve this, there must be horizontal level marks in all corners of the overlapped room. They are put in the process of building walls using a level, either a laser level, or a hydro level. And when the last row of masonry is done, the distance from the marks to the top of the walls is controlled with a tape measure. It should be the same in all corners. From my own experience, I can tell you for sure that some masons neglect this, especially when they make backing masonry at the same time as the front one, performed “under the bar”.

The top row of load-bearing walls should be bonded. That is, if you look from inside the overlapped room, then only poking should be visible on the load-bearing walls (on which the floor slabs rest) in the uppermost row of masonry.

If the slabs are placed on a load-bearing partition 1.5 bricks thick (i.e., the slabs rest on it on both sides), then the top row of such a partition is laid out in one of two ways:

Before laying floor slabs on walls from various blocks (foam concrete, gas silicate, slag, etc.), it is necessary to make a reinforced concrete belt (usually about 15-20 cm thick). Such a belt is made either by pouring concrete into the formwork, or using special U-shaped blocks around the entire perimeter of the house box, i.e. not only on load-bearing walls, but also on non-bearing ones.

When installing hollow core slabs, the holes in them must be sealed. It is much more convenient to do this in advance, while the plates are still on the ground. In general, SNiP prescribes to fill voids without fail on the side of the slab that rests on the outer wall (to reduce the likelihood of freezing of the slab), and on the side that rests on the internal partition, only starting from the third floor from the top of the house and below (to increase strength). That is, if, for example, the house has a basement floor, a floor between the 1st and 2nd floor and an attic floor over the 2nd floor, then it is mandatory to close the voids from the side of the load-bearing partitions only in the basement floor.

I will say that when laying the slabs, we always close up the holes. Moreover, in recent years, more and more hollow-core slabs come from factories with holes already sealed. It's comfortable. If the holes are not sealed, we insert a one-and-a-half brick (maybe even a half) into them and pass the remaining gaps with mortar.

Also, before installing the plates, it is necessary to prepare a site for the crane in advance. Well, if in the place where the crane will stand, the soil is, as they say, native, caked. Worse, when the ground is bulk. If you have a basement, you can not put the tap too close to the house, in order to avoid what is shown in the figure below:

In such cases, it is better to order a truck crane with a longer boom. Also, sometimes in the place where the crane will stand, you first have to put several road slabs (usually there are used ones somewhere). Often this has to be done in the fall in rainy and slushy weather, when the site is so “broken” that the crane simply gets stuck on it.

Floor slab laying.

Three people are enough for the installation of floor slabs. One clings to the slabs, two lay. If desired, you can cope with two, although not always. It happens that when overlapping, for example, the second floor, the installers and the crane operator do not see each other. Then at the top, in addition to 2 people directly laying the slab, there should be another person who will give commands to the crane operator.

Laying starts from the wall on a mortar layer of no more than 2 cm. The mortar must be thick enough so that the slab does not squeeze it completely out of the seam. After the crane operator places the slab on the walls, he first leaves the lines taut. At the same time, with the help of a crowbar, the plate, if necessary, is not difficult to move a little. If the upper surfaces of the load-bearing walls were made even, then the slabs will lie flat, without drops, as they say "from the first approach."

Regarding the size of the support of the plates on the walls, I will give an extract from the document “Manual for the design of residential buildings. Issue. 3 (to SNiP 2.08.01-85) 6. FLOORS ":

Paragraph 6.16.: The depth of support of prefabricated slabs on the walls, depending on the nature of their support, is recommended to be taken at least, mm: when supported along the contour, as well as on two long and one short sides - 40; when supported on two sides and a span of slabs of 4.2 m or less, as well as on two short and one long sides - 50; when supported on two sides and the span of plates is more than 4.2 m - 70.

When assigning the depth of support for floor slabs, the requirements of SNiP 2.03.01-84 for anchoring reinforcement on supports should also be taken into account.

In our practice, we try to support at least 12 cm, since now it is possible to purchase exactly the plates that are needed. The step of their lengths is 10 cm.

I often hear disputes about whether hollow core slabs can be supported on three sides (two short and one long) and how long it is possible to put the slab on the wall with the long side. From what is written above, it follows that it is possible to support the plates in this way. But it is not so. If you read the indicated SNiP, then it says that slabs that rely on three sides have a different reinforcement scheme than those that rely on only two sides.

The vast majority of hollow core slabs, which are now produced by reinforced concrete factories, are designed specifically to rest on two short sides, so it is not recommended to start them with the long side on the wall. Under a certain load, this can lead to cracking of the plate. The reinforcement scheme and, therefore, the possibility of supporting the slab on a third side must be clarified with the manufacturer.

Also, an error associated with improper loading of the slab is the overlapping of two spans at once (see the figure below):

Under certain unfavorable conditions, the slab can crack, and the place where the crack appears is absolutely unpredictable. If you still use such a scheme, make a cut with a grinder (to the depth of the disk) on the upper surface of the plate strictly above the middle partition. Thus, in which case the crack will pass exactly along this section, which, in principle, is no longer scary.

Of course, it’s good if we manage to overlap only with whole slabs. But the circumstances are different, and yet sometimes some plate (or even more than one) has to be cut along or across. To do this, you will need a grinder with a diamond blade for concrete, a sledgehammer, a crowbar, and not the most frail man at a construction site.

To facilitate the work, it is better to lay the stove on a lining. Moreover, this lining is placed exactly under the cut line. At some point, the plate will simply break along this line from its own weight.

First of all, we make a cut on the upper surface of the plate with a grinder along the cut line. Then, striking with a sledgehammer from above, we cut a strip along the top of the slab. It is quite easy to break through concrete in the void area. Next, we break through the lower part of the plate with a crowbar (also along the voids). When cutting the slab along (we always chop along the hole in the slab), it breaks rather quickly. When cutting across, if the slab did not break after the destruction of the lower part with a crowbar, a sledgehammer strikes from the side on the vertical partitions of the slab until the victorious one.

In the process of cutting, we cut the falling reinforcement. It is possible with a grinder, but it is safer by welding or a gas cutter, especially when the reinforcement in the slab is pre-stressed. A disk from a grinder can bite. To prevent this from happening, do not cut the reinforcement to the end, leave a couple of millimeters and then break it with a blow from the same sledgehammer.

Several times in our practice, we had to cut the slabs along. But we have never used, let's say, "stumps" with a width of less than 60 cm (less than 3 holes remain), and I do not advise you. In general, when making a decision to cut a slab, you take full responsibility for the possible consequences, because not a single manufacturer will officially tell you that it is possible to cut a slab.

Let's now see what can be done if, nevertheless, a whole number of plates is not enough for you to completely cover the room:

Method 1- we put the first or last (maybe both) plates without bringing the long side to the wall. We lay the remaining gap with bricks or blocks, hanging them no more than half from the wall (see Fig.):

Method 2- we make the so-called "monolithic section". From below, plywood formwork is placed under the slabs, a reinforcing cage is made (see the figure below) and the area between the slabs is poured with concrete.

Anchoring of floor slabs.

After all the plates are laid, they are anchored. In general, if the construction of a house is carried out according to the project, then an anchoring scheme must be present in it. When there is no project, we usually use the circuit shown in the figure:

The anchor is made by bending the end into a loop that clings to the mounting loop of the plate. Before welding the anchors to each other and to the mounting loops, they must be pulled as far as possible.

After anchoring, we immediately seal with mortar all the mounting eyes in the slabs and rustication (seams between the slabs). Try not to delay this so that construction debris does not get into the rusts, and water does not pour into the eyes during rain and snow. If you suspect that water did get into the slabs (for example, you bought slabs with voids already sealed, and rainwater could get in even during storage at the factory), it is better to let it out. To do this, after laying, simply drill a small hole in the slabs from below with a perforator, into those voids where the mounting eyes are located.

It is especially dangerous to find water in voids in winter, when the house is not yet heated (or not completed at all) and the slabs freeze below zero. Water saturates the bottom layer of concrete, and with repeated freeze-thaw cycles, the slab simply begins to collapse.

Another way of fixing the plates is the construction of the so-called concrete ring anchor. This is a kind of the same monolithic reinforced belt, only it is not made under the slabs, but in the same plane with them, also around the entire perimeter of the house. More often, this method is used on foam concrete and other blocks.

I must say right away that we have never used it because of the much greater laboriousness. I think the ring anchor is justified in more seismic regions than our Nizhny Novgorod region.

At the end of the article, I propose to watch a short video in which we are talking about the choice of floor slabs: