Laying floor slabs: technical requirements. Do-it-yourself installation of floor slabs How to properly cover floor slabs

When constructing residential buildings, industrial facilities and garages, there is a need to construct a floor above the basement of the building, between floors, as well as to form a roof structure. To solve the problem, the floor is laid on hollow-core slabs or a monolithic slab is poured. Knowing how to correctly lay floor slabs on walls, it is not difficult to make a perfectly level and sufficiently strong ceiling structure. Let's consider how reinforced concrete products should be installed in the desired position, as well as how they are positioned relative to each other.

What floor panels are used in construction?

To divide the building under construction into functional zones in construction, various types of overlapping structures are used:

. To construct a single slab, formwork is installed, a reinforcement cage is placed, and then concrete is poured. The design is characterized by increased load capacity and increased safety margin. However, the monolithic option has serious disadvantages. The process of constructing a structure is quite expensive and labor-intensive. For a solid slab, an increased volume of concrete solution is required. In addition, a massive reinforced concrete platform places an increased load on the foundation;
prefabricated ceiling. For its installation, standard panels manufactured at industrial enterprises are used. Consisting of individual elements, floor slabs have increased strength and are quickly installed using lifting equipment. It is important to ensure the flatness of the supporting surface at the installation site, as well as to seal the gap between the reinforced concrete slabs. When supported on two sides or in a U-shape, the rigidity of the structure is guaranteed. After resting on load-bearing walls, internal partitions are erected.

When constructing any premises, the question arises of how to install floor slabs

Using either solid ones for construction, it is easy to significantly shorten the construction cycle, reduce the labor intensity of activities, and also reduce costs. The prefabricated version surpasses the monolithic structure in terms of the listed indicators and is not inferior to it in strength properties.

Various types of panels are used, differing in design options:

Solid. They can be easily distinguished from other types of slabs by the absence of internal channels on the end surface. Solid products reinforced with steel reinforcement have increased strength, but have increased weight. Increased thermal conductivity and reduced sound insulation characteristics are the main disadvantages of a solid structure.
Void. The internal cavities of the slabs in cross section have the shape of a circle or oval. The popularity of hollow-core panels is associated with the reduced load transferred by hollow slabs to the foundation. The products are distinguished by increased noise insulation characteristics, as well as thermal insulation properties.
Ribbed. The panels are also called hip panels due to the shape of the cross section formed by longitudinal stiffeners. Parallel ribs increase the strength of the slabs and provide high load capacity. Ribbed slabs are resistant to deformation, but are inferior to hollow slabs in terms of thermal insulation.

The slabs used in the construction industry also differ in their manufacturing method:

slabs marked PC are molded in collapsible formwork and have standard dimensions;
PB brand panels are manufactured by continuous pouring of concrete and cut into pieces of the required length.

When constructing and constructing a building, it is necessary to take into account some nuances

One of the differences between the floor panels used is the method of connecting the reinforcement grid elements.

To assemble parts of the load-bearing frame, the following is used:

knitting wire;
electric welding machine.

Overall dimensions depend on the type of slabs and are:

length – 2.5-12.0 meters;
width – 1.0-1.5 meters;
thickness – up to 0.22 meters.

Having decided on the panel option, you should figure out how to properly lay floor slabs on the walls.

How to correctly lay floor slabs on walls - the main requirements

The reliability of building structures depends on the correct installation of slabs.

When carrying out installation operations, observe the following recommendations:

Install on the end plane of load-bearing walls. Carry out the construction of internal partitions after completion of installation operations;
Maintain the recommended dimensions of the supporting surface. The length of the support platform corresponds to the width of the slab, and the width of the support is 100-250 mm;
ensure reliable fixation of the panels. Fasten the slabs with special anchors, and also connect the products using the rigging eyes;

Before laying floor slabs, you need to know the technology and laying rules

check the horizontality of the end plane of the main walls. It is important to prevent the formation of height differences after laying the floor slabs;
Use a uniformly mixed cement mixture. Rocky impurities in cement mortar can cause panel distortions during installation.

In accordance with the requirements of building codes, it is recommended to install ceiling panels as follows:

with the short parts of the slab resting on two surfaces located on opposite sides;
with laying floor slabs on three end planes of the box, forming a contour in the shape of the letter P.

Compliance with the listed requirements allows you to avoid distortions during installation and prevent problematic situations.

Minimum size of the base surface during the installation of slabs

The value of the minimum permissible support is determined at the design stage by calculation, depending on a set of factors:

overall dimensions of the floor slab;
weight of the overlapping structure;
thickness of the building box;
dimensions of the thermal insulation layer;
presence of external finishing;
earthquake resistance of the building;
forces perceived by the plate.

You need to prepare the floor slabs before installing them

At the design stage, the duration of the load, as well as the intensity of its application, are taken into account. To perform calculations, representatives of design organizations use special software. Private developers should focus on tabular indicators determined by specialists when performing settlement operations.

Construction rules, as well as current regulatory documents, contain requirements for the size of the supporting platform for walls built from different building materials:

laying floor slabs on a brick wall is carried out provided that the width of the supporting surface is 90-120 mm;
the width of the support platform for walls built from gas-filled blocks and foam block composites is 100-120 mm;
The maximum width of the contact surface of the panels with the main walls of buildings reaches 250 mm.

The minimum permissible size of the supporting platform, equal to 60 mm, is allowed when installing slabs on large-panel type load-bearing structures. The reliability of the constructed floors is guaranteed if the recommendations contained in the current standards are followed.

How to properly lay floor slabs on walls - installation technology

The technology for carrying out the installation of floor panels includes the following main steps:

The floor slabs must be laid on a concrete mixture base

preparatory work. They provide for the transportation and storage of slabs at the construction site. It is important to prepare the supporting surface of the walls and know how to cut solid slabs into pieces if necessary;
main installation activities. To implement them, it is necessary to prepare lifting equipment, the necessary building materials, and tools. Then the internal cavities should be sealed, laid and anchored.

Each stage has its own characteristics. Let us dwell on the nuances of performing operations.

Getting ready to lay floor slabs - preparatory activities

Preparation for installation of floor panels is a responsible process that includes the following steps:

Preparing the site for placing lifting equipment
Delivery of purchased panels to the construction site and storage.
Preparation of equipment and tools.
Cutting additional elements.

Let's look at the specifics of each stage.

To prepare the work site for the location of the crane, the following work must be performed:

Remove large rocky inclusions and vegetation from the surface.
Prepare convenient paths for the access of vehicles with slabs.
Check the density of the soil, which should not be loose.
Plan the surface of the work site.

Floor slabs should be laid as close to each other as possible

When carrying out construction activities in the spring or autumn, road slabs should be laid over the entire surface of the crane site to ensure a stable position. Transport the slabs to the installation site using a vehicle of the required carrying capacity with a body length corresponding to the dimensions of the products. Install wooden pads between the panels on the car body.

To prevent cracking, it is important to store the slabs correctly. Please note the following points:

horizontal storage area;
installation of wooden spacers of the same thickness.

It is important to avoid touching the hollow panels and to place the support bars in a vertical plane.

To perform the work you will need the following equipment and tools:

lifting equipment;
slings;
anchors for fixing slabs;
massive sledgehammer;
Bulgarian;
assembly scrap;
cement mortar;
level, trowel and plumb line.

If it is impossible to use solid panels to form a floor, it becomes necessary to cut them into elements with the required dimensions.

To prevent the slabs from freezing during the cold season, the ends must be sealed

To do this you need:

Draw a chalk line corresponding to the required size.
Place a pad over the cutting areas to make it difficult to chip off the concrete.
Use a grinder to cut along the drawn line.
Hit the top of the slab several times with a sledgehammer.
Use a crowbar to break through the bottom of the slab and cut the reinforcing bars with a grinder.

Having completed the preparatory activities, proceed to the main stage of work - installation of the panels.

Scheme of laying slabs on the surface of load-bearing supports

Before placing floor slabs on the walls, check their horizontalness. It is important to eliminate differences in height using a cement mixture.

Further procedure:

Lay the cement mixture in a layer of 2-3 cm on the end plane of the load-bearing walls.
Secure the floor slab to the lugs and move it to the installation site.
Use a crowbar to guide the panel into the desired position.
Check the size of the supporting surface and lower the slab.
Disconnect the rigging and secure the products with anchors.
Seal the gap between the ends of adjacent slabs.

When an increased space is formed between the slabs and the wall, formwork should be installed, reinforcement should be laid and concreting should be carried out. To ensure increased thermal insulation, seal the end channels using mineral wool, rubble bricks or concrete mixture to a depth of 20-25 cm on each side of the product. After sealing, cover the channels with cement mixture.

Conclusion

Having figured out how to correctly lay floor slabs on walls, it is easy to form the floor of the basement of the building, mount the interfloor foundation, and also lay the floor elements in the upper part of the building. It is important to carefully study the technological process of installing slabs and use certified products produced at industrial enterprises. Considering the responsibility of performing installation operations, it is advisable to use the services of qualified builders. They will install the panels correctly and will not make mistakes.

The most reliable types of floors in construction are reinforced concrete floor slabs. This type of overlap between the floors of the house and above the basement is not suitable for all structures of a private house. Buildings whose walls are made of wood or panel houses should also be covered with wooden floors. But in a house built of brick or foam blocks, it is better to install reinforced concrete floors. These structures will last for many, many years without additional maintenance during their operation.

Reinforced concrete floor slabs are delivered to the construction site in the required quantity according to the project. Projects for private houses are usually developed in such a way that when installing slabs, unnecessary openings are avoided, except, perhaps, for the entrance to the basement, and then only if this is provided for in the project.

Reinforced concrete floor slabs should be mounted only on two load-bearing walls with their ends. Reliance on three points (in the form of walls or partitions) is unacceptable, since in such a case the floor slab will simply break (crack) and its further operation will be impossible.

Floor slabs are mounted on cement mortar grade M 100, it is spread over the reinforced belt in a layer of about 30 mm. The support of the slabs on load-bearing walls must be at least 80 mm on concrete and 120 mm on brick.

Voids in reinforced concrete slabs at one end are sealed with concrete at reinforced concrete factories. The slabs with this side are mounted on external walls, the holes in the slabs are closed to prevent the walls from freezing in these places. If the voids in the external walls are not closed, then you can seal the holes yourself with broken bricks and cement mortar.

When installing the floor slabs, they are aligned along their lower part; the seams of the elements should be on the same horizon when looking at the structure from below. The seams between the slabs after their installation are sealed with concrete on fine crushed stone or cement mortar. If there are voids between the floors of more than 50 mm, these places should be reinforced with the installation of suspended formwork. Concrete for such monolithic areas is used grade M 200.

After completing the installation of the floor slabs, they should be fastened together. This type of work is called anchoring. This work cannot be neglected, since the anchors give rigidity to all mounted slabs.

For anchors, 10 mm reinforcement is used. The reinforcement is welded to the hinges of the mounted slabs and thus the floors are connected.

The slabs resting on the external walls are fastened with anchors in the shape of the letter T. One side of the anchor is welded to the mounting loop of the slab, and the second will be fastened with masonry during the further construction of walls made of bricks or foam blocks.

For this simple job, you will need to order lifting equipment and a team of installers of 3-4 people.

Laying floor slabs. Process video

When building any house, sooner or later the question arises of how to install floor slabs. This matter, like any other in construction, requires a scrupulous and attentive approach and some theoretical and practical knowledge in this area.

Floor slabs are an indispensable material in the construction of buildings and structures of various types.

Types of floor slabs

First of all, you should understand what the floor slabs themselves are.

The most common today for the installation of floors are reinforced concrete hollow-core slabs.

Plates are divided into several types:

multi-hollow;
tents with ribs along the contour;
long ribbed.

You can use, but firstly, it is very expensive, and secondly, installing them is a very complex and time-consuming process. Therefore, the most common today for the installation of floors are reinforced concrete multi-hollow slabs, which in turn are divided into round-hollow and with oval voids. But the most common at the moment are round-hollow.

In addition, these materials have a number of advantages over others, for example, they have better thermal conductivity and sound insulation, which is achieved due to the numerous voids inside the slab, and it is thanks to these voids that this type is the lightest of all suitable for installing floors.

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Methods for dividing reinforced concrete slabs into parts

First, you should think about how you can separate the desired piece of slab if necessary. After all, it is quite possible that in the process there will be a need to make it a little shorter. It is not very advisable to order elements of different sizes at once, because it is not known exactly how many such materials may be needed, and sometimes only in the process of work can you see which one is needed or whether it is necessary to trim the reinforced concrete slab in order to make a hatch in it.

When cutting floor slabs, use a bolt cutter with the highest power.

So, in order to cut the slab, you need to have a crowbar and a grinder.

First, you need to mark the required length with chalk; you need to put a backing under the slab exactly along the strip marked with chalk - this is necessary so that when cutting the element itself, the concrete does not “slick”.

Then, using a concrete disc with a grinder, you need to cut the element along the chalk mark, and then hit all the voids near the slot several times, then hit the edge several times on the side. Usually at this stage the unnecessary piece of reinforced concrete slab will already settle under the weight of its weight. After this, you need to break through the lower part of the pipes with a crowbar and cut the exposed fittings with a grinder (only now using a metal disc).

If it is necessary to chop off part of the workpiece not across, but along, then the principle remains the same, only now you will also have to cut with a grinder the metal mesh that comes across during the cutting process, and the process will take much longer, since they can be very large in length.

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How to install reinforced concrete floor slabs

Installation of floor slabs is a rather labor-intensive and risky process, so its preparation should be approached with all responsibility. The technology for installing floors is not as difficult as it might seem at first glance, if you prepare for it correctly.

In order to install floor slabs, you will need:

round hollow-core reinforced concrete slabs;
truck crane;
concrete solution;
Master OK;
grinder or autogen;
sledgehammer.

Before laying the slabs, it is necessary to lay out a base of concrete or cement mortar.

After the materials have been delivered and properly unloaded, it is necessary to drive the truck crane to the house at a pre-selected location. In places where it is planned to lay floor slabs, it is necessary to lay out a backing made of concrete or cement mortar. Then, using a truck crane, you need to hook the reinforced concrete slab to the hinges located on the workpieces, carefully, constantly monitoring the process, lift it to the desired height and install it in a predetermined place. Of course, it would be strange to expect that it will immediately and easily fall into the right place, so it must be moved with a crowbar to the required position. So, lifting by the hinges, all floor slabs are installed. Installation of slabs should be carried out, if the technology is followed, on a concrete solution. Due to the fact that the slabs are installed directly on the mortar, they remain movable for some time and, if necessary, can be adjusted using a crowbar. Then, when the materials have already been laid as expected, you need to attach them using anchors to the hinges to the walls of the house.

Between the two slabs along their entire length there is a rust that must be carefully repaired. There are many small depressions on the sides of hollow-core reinforced concrete slabs. After the rustications between the slabs are sealed, thanks to these recesses the slabs will become a single integral structure.

After the slabs have been laid and the rustications have been sealed, you should begin sealing the ends of the slabs; if this is not done, the slabs will freeze in winter.

In order to seal the end of the slab, you can use several methods:

Mineral wool. It should be inserted into the holes of the slab to a depth of approximately 20 or 30 cm.
Fill with lightweight concrete to a depth of approximately 25 centimeters.
Seal it with backing bricks and cover it properly with mortar.

You can seal the holes in the slabs at the stage of preparation for installation, this will be a little more convenient.

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Features of technology when installing floor slabs

Installation of all floor slabs occurs by lifting the slabs using special hinges using a truck crane.

Reinforced concrete floor slabs are installed exclusively on the main walls of the house; all internal partitions and walls are erected only after the installation of the slabs is completed.

It should be taken into account during the installation process that the elements must rest on the wall of the house by at least 120 mm. Adjacent slabs must be fastened together using mounting loops.

It is necessary to take into account that the technology for installing floor slabs requires that in no case should a double span be covered instead of two short elements, for example, with one long slab - in this case, the material will not withstand the load and will burst, which can lead to catastrophic consequences. The same can happen if the workpiece for the balcony is pushed a little forward, leaving part of it on the street, only here the first frosts can also have an effect: the cold will go straight through the material, and also, crushed by the wall, it can burst.

All walls of the house must be at the same level, otherwise between the floor slabs you will get some kind of “steps” that are completely unnecessary and which will be difficult to get rid of later.

Be sure to take into account that the elements must rest on the wall of the house by at least 120 mm

When starting to install floor slabs, you should know that there are special requirements for the mortar on which they will be laid: this mortar must be made sufficiently liquid and it should be applied minimally to the walls, and when making the mortar, the sand must be carefully sifted, otherwise even a small pebble will negate all efforts to install a flat ceiling.

It happens that there is a need to make a hole in a reinforced concrete floor slab, for example, to access the attic. In this case, you first need to draw a rectangle of the required size on the element with chalk, then use a grinder to lightly trim the element along the drawn lines. After this, you can pierce the element with a sledgehammer until the reinforcement appears. The reinforcement needs to be cut with a metal disc using an angle grinder, however, you need to be careful here, since the reinforcement inside the reinforced concrete blank is highly stressed, this can lead to pinching of the angle grinder disk. Therefore, it is best not to cut it a little with a grinder, and then break it with a sledgehammer. If you have an autogen on hand, then cut the reinforcement with an autogen.

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Filling small voids without using slabs

There are cases when the width of one piece is not enough to cover the entire void, and a very narrow space remains. Workpieces of such a small width are usually not made - it is impractical; cutting a reinforced concrete workpiece takes a very long time. Then you can apply the following methods.

1. You should calculate in advance whether or not the width is enough to cover the entire space. If it is clear that there will not be enough of them and there will be, for example, half a meter left, then in this case the first slab must be mounted at a distance equal to half of what should remain, then we install the ceiling according to the technology, fastening the hinges.

As a result, very small gaps remain along the edges of all the laid elements, which can be easily filled with a cinder block, laying it with its end face, which will rest against the material, thereby being securely held in the right place. The cinder block, of course, needs to be fastened together with each other and the workpiece using a solution.

2. Reinforced concrete slabs should be installed along the entire floor in such a way that there are equal small gaps between them. After installation, it is necessary to attach formwork to these gaps, install reinforcement and fill everything with concrete. This method is more labor-intensive, but also more reliable.

During the construction of any structure, floors are used to ensure structural strength and impart rigidity to multi-level buildings. Builders typically use three main methods to install them. Installation must be carried out by experienced specialists with the necessary knowledge in the field of construction.

Peculiarities

As mentioned above, the most reliable are three options for constructing floors:

installation of monolithic reinforced concrete slabs;
installation of conventional slabs;
laying timber beams.

It should be noted that all floors differ in shape, structure and technical characteristics. The shape of concrete slabs can be flat or ribbed. The first, in turn, are divided into monolithic and hollow.

When constructing residential buildings, hollow-core concrete floors are often used because they are cheaper, lighter and have a higher sound insulation rate than monolithic ones. In addition, internal holes are used for laying various communication networks.

During construction, it is extremely important to decide already at the design stage on the choice of the type of floors, taking into account all technical factors.

Each manufacturer produces slabs of a certain range, their quantity is limited. Therefore, changing the material during the installation process is extremely imprudent and costly.

When using slabs, certain rules must be observed on the construction site.

It is better to store purchased floors on a site specially designated for this purpose. Its surface must be smooth. The first slab should be laid on wooden supports - bars 5 to 10 cm thick so that it does not come into contact with the ground. Between subsequent products, there are enough blocks of 2.5 cm in height. They are placed only along the edges, there is no need to do this in the middle. The stack should not exceed 2.5 meters for safety reasons.
If you plan to use long and heavy beams during construction, you should take care of auxiliary construction equipment in advance.
All work must be carried out in accordance with the project, which must be drawn up taking into account the requirements of SNiP.
Installation is permitted only to adult workers who have permission and relevant documents confirming their qualifications.
When installing floors of multi-level structures, climatic conditions should be taken into account. SNiP standards regulate wind speed and visibility restrictions.

Preparation

Any construction has its own project, which is created on the basis of several regulatory documents. Main sections of the project.

Budget plan, describing all costs and deadlines.
Routing indicating all processes at the facility, describing the labor intensity of each stage and the requirements for the resources used. It should provide instructions for performing specific tasks, indicating effective methods of carrying out work, as well as compliance with safety measures. The map is the main regulatory act of any project.
Executive scheme. Its sample is regulated by GOST. It contains information about the actual execution of design work. It includes all changes made to the project during construction, as well as agreements with contractors for installation. The diagram reflects how correctly the structure was erected, whether it complies with accepted standards (GESN, GOST, SNiP), whether safety measures were observed, etc.

Before laying the floors, leveling should be done, that is, make sure that the load-bearing horizontal plane is ideal. To do this, use a level or hydraulic level. Professionals sometimes use a laser level option.

The difference according to SNiP is no more than 5-10 mm. To perform leveling, it is enough to lay a long block on the opposite walls, on which the measuring device is installed. This establishes horizontal accuracy. Similarly, measure the height in the corners. The obtained values are written directly on the walls with chalk or marker. After identifying the outermost points above and below, leveling is carried out using cement.

Before installing the floors, formwork is performed. You can do it yourself or use the factory version. Ready-made purchased formwork has detailed instructions that describe the entire installation process, right down to height adjustment.

When erecting wooden floors, no formwork is needed; the existing supports are sufficient.

If the walls are built from gas silicate materials or foam concrete, then before installing the floors they need to be further strengthened. For these purposes, a reinforced belt or formwork is used. If the structure is brick, then the last row before the ceiling needs to be made into joints.

In preparation for construction and installation work You should prepare the components for the solution in advance - cement with sand and water. You will also need expanded clay or crushed stone to fill the holes before rough finishing.

In hollow-core floors, according to SNiP, it is necessary to seal the holes on the side of the outer wall. This is done to prevent it from freezing. It is also prescribed to close the openings from the inside, starting from the third floor and below, thereby ensuring the strength of the structure. Recently, manufacturers have been producing products with already sealed voids.

If lifting equipment is required for construction, then at the preparatory stage it is necessary to provide a special site for it. The soil must be compacted to avoid crumbling. Sometimes builders place road slabs under the crane.

Before installation, the floors must be cleaned of dirt, especially if there are traces of old concrete left on them. If this is not done, the quality of the installation will suffer.

At the preparatory stage, the waterproofing of the foundation is checked for the absence of breaks and defects.

Installation

To install the slabs, three people will be required: the first one hangs the part from the crane, the other two install it on site. Sometimes during large-scale construction a fourth person is used to correct the work of the crane operator from the outside.

Installation work of floor slabs is carried out in accordance with the technology regulated by SNiP standards, as well as in accordance with the drawing and layout agreed upon in the project.

The thickness of the partition is calculated depending on the designed load. If reinforced concrete slabs are used, they must be at least 10 centimeters wide, for ribbed options - from 29 cm.

The concrete mixture is prepared immediately before installation. It is better to order it from specialized companies so that it has brand strength. The solution consumption rate is determined at the rate of 2-6 buckets for laying one slab.

Installation begins from the wall, where a sand-cement mixture 2 cm thick is laid out on a brick or block support. Its consistency should be such that after installation of the ceiling it is not completely squeezed out.

In order to place the slab correctly and accurately, it does not need to be immediately unhooked from the crane slings. To begin with, with the suspensions tense, the ceiling is leveled, and then lowered completely. Next, builders check the height difference using a level. If a certain evenness cannot be achieved, then you will have to raise the slab again and adjust the height of the concrete solution.

Experts warn that It is better to install hollow core slabs on two short sides. In addition, you should not cover several spans with one ceiling, as it may burst in an unexpected place. If, nevertheless, the scheme provides for one slab for 2 spans, then several runs should be made with a grinder in the places of the jumpers. That is, an incision is made along the upper surface above the central partition. This ensures the direction of the crack in the event of a future split.

Prefabricated monolithic or hollow core floors have a standard length. Sometimes other dimensions are needed for construction, so they are divided with a saw with a diamond blade. It is important to remember that it is impossible to cut round hollow-core and flat slabs lengthwise, which is due to the location of the reinforcement in the support zones. But monoliths can be divided in any direction. Cutting a cast-in-place concrete block may require the use of rebar cutters and a sledgehammer.

First you need to make a cut on the top surface along the intended line. Then a sledgehammer is used to break through the concrete in the void area and break the lower part of the slab. During work, a special lining is placed under the cut line, then at a certain depth of the hole made, a fracture will occur under its own weight. If the part is cut lengthwise, then it is better to do it along the hole. Internal reinforcing bars are cut with a gas tool or safe welding.

Professionals advise not to cut the reinforcement with a grinder until the very end; it is better to leave a few millimeters and break them with a crowbar or sledgehammer, since otherwise the disc may get stuck and break.

No manufacturer takes responsibility for a cut slab, since this procedure violates its integrity and, consequently, its technical characteristics. Therefore, during installation it is still better to avoid cutting and use intact parts.

If the width of the slab is not enough, then it is proposed to make monolithic concrete screeds. Plywood formwork is installed below two adjacent slabs. U-shaped reinforcement is placed in it, the base of which lies in the recess, and the ends extend onto the floors. The structure is filled with concrete. After it dries, a general screed is made on top.

When the installation of the ceiling is completed, the process of laying the reinforcement begins. Anchoring is provided to fix the slabs and impart rigidity to the entire structure.

Anchoring

The anchoring procedure is carried out after the ceiling is installed. Anchors fasten the slabs to the walls and to each other. This technology helps enhance the rigidity and strength of the structure. Fasteners are made of metal alloys, often galvanized or stainless steel.

Methods of interfloor connections depend on the presence of special loops.

For slinging high-density elements, fastenings in the shape of the letter “L” are used. Their bend length ranges from 30 to 40 centimeters. Such parts are installed 3 meters from each other. Adjacent slabs are fastened transversely, the outer ones - diagonally.

The algorithm for anchoring is as follows:

the fastener is bent on one side under the eye in the slab;
adjacent anchors are tightened to the limit, after which they are welded to the mounting loop;
interpanel seams are closed with mortar.

For hollow products, slinging is carried out similarly, but an additional reinforced concrete row is laid around the perimeter. It is called a ring one. The fastener is a frame with reinforcement filled with concrete. It additionally fastens the floors to the walls.

Anchoring can be done by two workers.

Safety precautions

When performing installation and preparatory work, certain safety regulations must be observed to prevent accidents. They are prescribed in all construction regulations.

All preparatory and organizational activities in the field of construction are prescribed in SNiP. Among the main ones we can list the following.

All employees must have the necessary permits and other documents allowing them to carry out such activities. Engineering and technical personnel must be instructed and familiarized with safety precautions. Crane operators and welders are required to have special training confirmed by certificates.
The construction site must be fenced off from outsiders to avoid misunderstandings and injuries.
The project must obtain all permits and approvals from government regulatory agencies and other inspection organizations. These include, in particular, surveyors, firefighters, technical supervision, cadastral services, etc.
The construction of the upper levels of a multi-story building is possible only after complete installation of the lower ones; the structures must be completed and rigidly fixed.
If it is not possible to give signals to the crane operator visually (for example, during the construction of large objects), a light and sound alarm system, communication by radio or telephone should be installed.
Cleaning of floors is carried out before they are lifted into place.
Installation is required according to the established layout diagram.
If there are no mounting loops, the part does not participate in lifting. They are either discarded or used for other work that does not require transportation.
Prefabricated parts must be stored separately.
When constructing multi-storey structures, rules for working at height are mandatory.
Standing on the stove while it is being transported is strictly prohibited.
Providing workers with personal protective equipment is the responsibility of the employer. You cannot be on the court without a helmet.
Removing products from the slings is possible only after they are firmly secured to the working surface.

These are just the basic rules. SNiP provides much more conditions for the safe performance of construction work when laying floors.

A reliable and durable house is not only strong, stable walls and a leak-proof roof, but also equally strong, earthquake-resistant floors. For the arrangement of interfloor ceilings and between the basement and the first floor, solid and hollow-core reinforced concrete slabs are used. These products are made of hard or lightweight concrete and reinforced with special reinforcement. The floors are durable, fire-resistant, resistant to mechanical stress and exceptionally strong. There are several types of reinforced concrete slabs, each of which is used in one situation or another. Therefore, in order not to make a mistake with your choice, you need to pay attention to the markings and understand what stands behind the designations in it. But an even more important and responsible task is the laying of reinforced concrete slabs, which is carried out using a crane and a team of workers. We will tell you in this article how to lay reinforced concrete slabs on floors in accordance with the technical specifications so that you can monitor the progress of the work.

What are reinforced concrete slabs?

To an uninitiated person it may seem that reinforced concrete floor slabs are all the same; you just need to call the factory and tell them the required quantity. In fact, concrete factories produce slabs and blocks of various designs, purposes, and even from different grades of concrete. Therefore, first of all, pay attention to the markings of the slabs.

Marking of reinforced concrete slabs

For example, brand PK57-15-8T means:

PC- name of the product/type of slab. In this case, a floor slab with round voids.

57-15 - dimensions of reinforced concrete slabs indicated in dsm. In this case, the slab is 5680 mm long and 1500 mm wide.

8 - permissible load on the slab. In this case, the design load is 800 kgf/m2.

T- brand of concrete. In this case, heavy concrete is used.

Sometimes the markings indicate the thickness of the reinforced concrete slab. Then it looks like this P-27-15-12-8T. This designates a solid reinforced concrete slab 2690 mm long, 1490 mm wide, 120 mm high, with a load of 800 kgf/m2 made of heavy concrete.

Types of reinforced concrete slabs

As we have already found out, the first letter values in the marking indicate the type of slab. Let's find out what they are and what is hidden behind them.

P - reinforced concrete solid slabs, are used for installation of floors in residential and public buildings. Available in different sizes: length from 1790 mm to 6260 mm, width 1190 - 1490 mm, thickness 120 mm, 160 mm, 220 mm. The weight of a solid reinforced concrete slab depends on its size and ranges from 0.625 t to 3.6 t. For example, the P-48-12-22-8AT5 slab weighs 2.65 t, and the P-30-15-16-8A3 slab weighs 1.775 tons. Such slabs are much heavier than hollow-core ones. Slabs with a height of 160 and 220 mm provide sufficient sound insulation of the room due to their mass, but if you use slabs with a height of 120 mm, then additional sound insulation measures must be taken, for example, making layered floors.

PC - reinforced concrete floor slabs with round voids. They are also used for floors, but unlike solid slabs they provide exceptional sound and heat insulation of the room due to the air trapped in the voids. Available in the following sizes: 100 mm wide slabs have a length from 238 mm to 1198 mm; slabs with a width of 120 mm have a length of 168 - 898 mm; slabs with a width of 150 mm have a length of 238 - 898 mm. The height of the slabs with round voids is the same - 220 mm. It is advisable to immediately find out information about how much a reinforced concrete slab weighs from the manufacturer on its website. For example, the most commonly used PK45-12-8 slab weighs 1.58 tons, the long PK72-15-8 slab weighs 3.33 tons, and the PK120-10-8 product with dimensions 1198x100x22 weighs 5 tons.

PS - reinforced concrete slabs for special purposes. This category includes slabs for balconies, loggias, bay windows and for floors sanitary facilities. Their main difference from other slabs is the method of support and the presence of additional holes for laying water supply and sewerage pipes. The height of such slabs is 200 mm.

ETC - ribbed reinforced concrete floor slabs. They are used for installing floors of brick residential and public buildings, as well as for arranging the load-bearing base of the roof. They are also sometimes called “tent”, since their size allows them to completely cover the room. The length of such slabs can reach 18 m, width 3 m, and height 300 - 600 mm.

RP - reinforced concrete slab spacers. Installed between building columns. May also be called spacer floor blocks. Usually their length does not exceed 1.5 m.

PT - heavy concrete slabs. Used for floors between columns in public buildings on the ground floor.

In addition to the above, there are also slabs made of lightweight concrete, as well as lightweight PNO slabs, which can withstand the same load as those made from heavy concrete, although they have less weight and thickness.

The price of reinforced concrete slabs depends entirely on their size and type. For example, a PK55-12-8 slab costs 150 USD. each, the most expensive large-sized slabs PK76-15-8 cost 500 USD. a piece.

Construction of a reinforced concrete slab for the foundation

All of the above types of slabs are manufactured at the factory and purchased ready-made. But there is another category - reinforced concrete foundation slabs. Such slabs are manufactured directly on the construction site.

At the site where it is planned to install a monolithic slab foundation, soil is excavated, the base is compacted, crushed stone and sand are filled in, and even more thorough compaction is carried out. Then the formwork is formed from metal panels with supports.

Next, the reinforcement frame is tied or welded, which is lowered into the formwork. For reinforcement, a rod of 8 - 12 mm in diameter is used. Next, everything is filled with concrete. After hardening, a monolithic foundation slab is obtained - strong, without cracks, with exact dimensions and the required thickness. Typically, such a foundation is required for moving soils.

Technology of working with reinforced concrete slab

The most popular slabs in private housing construction are multi-hollow reinforced concrete slabs with round voids. They can be ordered at the manufacturing plant, from where a car with the goods will arrive at the appointed time. But what to do next? How to store these slabs so that they do not crack? And then, when the actual installation of the slabs begins: how to cut off the excess? How to cut a hatch hole into the attic? Many similar questions may arise, so let’s dwell in more detail on the technology of working with reinforced concrete slabs.

How to store reinforced concrete slabs

Despite the strength of reinforced concrete slabs, the possibility of cracks cannot be ruled out. There are only two reasons - improper transportation and improper storage. Considering how much a reinforced concrete slab costs, each of them must be handled with care.

Storage of reinforced concrete slabs:

Only in horizontal position.
At a sufficient height so that the slabs do not touch the ground.
Under the slabs it is necessary to place a strong, reliable base that can withstand heavy weight, and it should not get wet or rot. Otherwise, moisture may get into the slab, it will get wet and cracks will appear.
The height of the base should be such that even if it subsides, the slabs will not touch the ground. If the bottom slab comes into contact with wet ground, cracks may appear not only on it, but also on the ones above.
Wooden slats 40 - 50 mm thick are laid between the slabs in one stack. They should be located strictly one above the other and at a distance of 20 - 40 cm from the edge.
The maximum number of slabs in one stack, provided the base is sufficiently strong, should be 8 - 10 pieces.
Do not store them in a vertically inclined position, leaning against the wall.

These tips will help protect slabs from cracking.

How to shorten a hollow core reinforced concrete slab

Among all the standard products that the plant can produce, you can always find slabs of the required size. But there are situations when, for various reasons, the slab needs to be shortened either in length or in width. To do this you will need a grinder, a crowbar and a cam hammer.

We lay the slab horizontally on the lining.
We draw a marking line on the surface of the slab along which we will cut.
The lining should be strictly under this line.
Using a grinder with a concrete disc, we cut the slab along the line, cutting through the upper part of the slab.
Using a hammer-fist, we tap the slab in place of the voids along its entire width. Usually 3 - 5 blows are enough to cut the slab where the voids are.
To cut the ribs, we strike them with the same fist, only not from above, but from the side.
A piece of slab destroyed to half will sag under its own weight, so that a crowbar can be easily inserted between the parts. Using a crowbar, we break through the bottom wall at the thinnest point of the round hole in the slab.
There should be reinforcement underneath, clean it from any remaining concrete and cut it with a grinder.

The edge of the slab will not be as smooth as that of the factory product, so it must be buried at a sufficient distance onto the supporting wall.

Cutting a slab lengthwise/lengthwise:

We also lay the slab on supports in a horizontal position and draw a cutting line.
Using a grinder, make a cut along the line.
Then tap the entire line with a hammer. It will be easy to destroy the top wall of the slab, since the cut will run along the line of the hollow hole.
We destroy the bottom wall in the same way.
If there are reinforcing bars with a diameter of 3 - 8 mm, cut them with a grinder.

Important! Please note that the reinforcement in a reinforced concrete slab may be stressed, so it cannot be cut to the very end. Otherwise, the fittings may jam the grinder disc. The rod is not cut completely, and the remaining piece is knocked off with a hammer or crowbar.

How to lay reinforced concrete slabs if they are not enough for the width of the room

What to do if the total width of all the slabs is not enough to cover the entire room. There remains, for example, 500 mm, which can be cut off from the new slab, or you can try to seal it in another way.

Method 1. Leave gaps on the sides:

We divide the total gap into two parts of 250 mm each. We lay the first floor slab at a distance of 250 mm from the edge of the wall.
We lay all other slabs end to end, without gaps.
There should also be a gap of 250 mm between the last slab and the wall.
We take a cinder block with a length of at least 500 mm, lay it with the butt side facing the slab on a cement mortar.
We carry out the cinder block masonry according to the sample, pressing it against the slab. On both sides of the room.

When the wall continues to be built, its masonry will press the cinder block even more tightly and secure it completely. For greater reliability, when screeding the floor on the upper floor, you can use a reinforcing mesh made of a rod with a diameter of 6 mm.

Method 2. Leave gaps between the plates:

We distribute the total size of the gap between all slabs. For example, the width of the room is 7800 mm, the slab is 1200 mm wide. Let's do the calculations: 7800/1200=6.5. We multiply the whole number of slabs by the width of each 6x1200 = 7200 mm, subtract 7800 - 7200 = 600 mm from the total width of the room. We have 6 whole slabs, so there will be 5 gaps between them, divide 600/5 = 120 mm. In total we should have five gaps of 120 mm each.
We lay the first slab flush against the wall.
The next one is indented 120 mm.
All others are also indented 120 mm. The latter should be adjacent to the wall.
We tie the formwork under the gaps.
We insert a frame made of reinforcement inside and tie it to the slabs.
Fill it with concrete.

All further work can be continued only after the concrete in the gaps between the slabs has gained maximum strength.

How to cut a hatch to the attic in a hollow reinforced concrete slab

When laying reinforced concrete slabs on an attic floor, there is almost always a need to cut out a hatch in the ceiling leading to the attic.

The main rule: the hatch is always cut at the junction of two slabs, and not in one slab.

The permissible dimensions of the hatch depend on the width of the reinforced concrete slab and its load. The wider the slab and the less loaded it is, the larger the hatch can be cut. The dimensions of the hatch are selected based on the dimensions of the stairs: 600x1200 mm, 600x1300 mm, 700x1200 mm, 700x1300 mm and 700x1400 mm.

The large side of the hatch is located along the slabs. For example, a 600x1200 mm hole is made like this: a cut is made at the junction of the plates, then one plate is cut by 300 mm, the opposite by 300 mm, and then a cut is made along 1200 mm.

How to lay reinforced concrete slabs

We have sorted out the basic questions about working with slabs, now the most important thing is laying the floors. Despite the apparent simplicity of the work algorithm, there are still some nuances that must be known and taken into account. Even before ordering slabs from the factory, it is necessary to complete all preparatory measures, since when the truck with the slabs arrives, everything should be ready for laying.

Preparatory work

Task one - ideal bearing surface. This means an ideal horizon without a monstrous height difference of 4 - 5 cm. This is unacceptable. We check the surface of the walls; if there are significant deficiencies, we level the surface using concrete mortar. Accordingly, you will have to wait until it gains maximum strength, and only then begin installation.

Task two - strength of the support zone. If the house is made of stone materials - brick, concrete, blocks, then no additional actions are required.

Important! If the walls are made of gas blocks or foam blocks, then before laying the reinforced concrete floor slabs it is necessary to fill in an armored belt. Formwork is carried out along the entire perimeter of the building; a reinforcement frame made of 8 - 12 mm rod is inserted inside. Then everything is poured with concrete. Further work is possible only after the concrete has hardened.

Task three - installation of mounting towers. They are needed in order to take on the weight of the slab if for some reason it slides off the supporting surface. The tower is used only during installation, then it is removed.

Laying reinforced concrete slabs using a crane

When all the preparatory work is completed, everything that needs to dry and gain strength has dried and gained strength, you can order the slabs. To unload and lay them, you will need a crane; depending on the size and weight of the reinforced concrete slab, it can have a lifting capacity of 3 to 7 tons.

You can lay the slabs directly from the machine without unloading. To do this, the construction foreman must have design documentation for the house, which indicates the layout of the slabs.

Laying reinforced concrete slabs - diagram

Stages of work:

First you need to prepare the supporting surface. At a depth of 150 mm, a concrete solution is applied in a layer of 2 - 3 cm. It is necessary to cover the entire surface on which the slabs will now be laid. If the method of leaning is on two sides, then only from opposite walls. If the method of support is on three sides, then it is necessary to apply the solution to three walls. You can lay the slab on top when the mortar reaches 50% of its strength.
At this time, the crane operator can hook and lift one of the plates.
A signal is given to the crane operator, the slab can be lowered to the prepared place. The person goes to a safe distance. Holding the slab with hooks, turn it around to dampen the swinging.

When the stove is very close, two people - one on one wall, the other on the opposite, carefully guide the stove to the right place. The slab should rest on the walls at least 120 mm, preferably 150 mm. The plate will squeeze out the excess mortar and take a convenient place, distributing the load evenly on the base.
After complete leveling of the slab, which can be done using a crowbar, the slings are removed from the mounting lugs. Leveling the slab can only be done along the laying area, never across it, otherwise the walls may collapse. A signal is given to the crane operator to pick up the slings.

The procedure is then repeated for all other slabs. In this case, it is necessary to align the slabs along the lower edge, which will be the ceiling in the room. To do this, the slabs are laid with the wider side down and the cone-shaped recess up.

Important! In some sources you may find a recommendation, in addition to the mortar, to place reinforcement under the slabs in the area of support. This is explained by the fact that it is more convenient to move and level it this way than without anything. In fact, you can’t put in reinforcement; it’s prohibited by the TTC. Firstly, the load will be unevenly distributed, and secondly, the slab will easily slide over the reinforcement, so it can move out of place.

If a non-standard option for supporting the slab is provided, then there are special steel elements for this. But it is better not to perform such work without a specialist.

Tying the slabs together - anchoring

The so-called anchoring can be performed in various ways - by tying the slabs together with reinforcement or by arranging a ring anchor in which the slabs will be clamped on all sides.

Rods with a diameter of 12 mm are welded to special fasteners on a reinforced concrete slab, connecting the slabs to each other. Different manufacturers provide different locations for such elements. It is considered the most optimal when these rods are located diagonally to the slab, i.e. connect points not at the same level, but with a displacement.

The slabs are anchored not only to each other, but also to the wall. To do this, reinforcement must be embedded in it in advance.

The ring anchor is somewhat reminiscent of an armored belt. Along the entire perimeter of the slabs, formwork is made 10 - 15 cm wide; a frame is inserted into it, in the corners of which the reinforcement is bent. Then concrete is poured into the formwork. The resulting structure is very durable.

Sealing joints between reinforced concrete slabs

The joints between floor slabs, also called rustications, are filled with fine-grained concrete grade M150. If the gaps are large, then a board/formwork is installed under them. All work on sealing rusts begins only after all the slabs are connected to each other. The slab will be able to withstand full load the very next day. Naturally, if the gaps between the plates are not too large.

Sealing voids at the ends of slabs

The voids at the ends of the slabs must be filled with something at least 20 - 30 cm deep. This is necessary to ensure that the slabs do not freeze and do not let in cold from the street. You can push mineral wool into the voids, you can fill them with concrete mortar, plug them with ready-made concrete plugs, or fill them with rubble bricks and seal them with mortar.

It is necessary to seal voids in floor slabs not only on those sides that rest on the external walls, but also on those that are inside the house and rest on the internal partitions.

All work on laying slabs takes several hours, from 2 to 4. Since the crane is paid hourly, it can be released immediately after laying the slabs on the floor. And you can do anchoring, filling rustications and voids in the ends yourself, slowly and without looking back at the time.