How to make a monolithic overlap. How to pour concrete floors

The construction of a house and a number of other buildings involves the mandatory arrangement of interfloor or attic floors. Often, wood is used to implement this task. Wooden floors easy to install, but if you need to provide high-quality insulation and sound insulation of the room, give preference to concrete floors. A monolithic concrete floor can be made independently. Read the instructions and get started.

Before starting any work, it will be useful to familiarize yourself with the rules for laying monolithic slabs. The main recommendations are as follows:

the span length can be no more than 900 cm. This is the maximum allowable length of one monolithic slab;
special equipment must be used to lift the slabs. In accordance with this requirement, hinges must be mounted in the slab, by hooking on which the crane can lift the product to the desired height. Relevant for those situations when the plates are bought in ready-made either they are made independently, but on the ground;
slabs can only be laid on pre-leveled walls. There should not be any significant distortions and drops;
from each edge, the plate should rest on the wall by 9-15 cm;
the slabs are laid with the obligatory sealing of technological seams and, in general, all cracks with a mortar. "Dry" laying is unacceptable;
during the installation of the plates, it is necessary to constantly monitor the evenness of their laying. Plumb and level are used for checking;
boards may only be laid on bearing walls. All kinds of piers are erected strictly after the completion of the arrangement of the floors;
if a hatch needs to be made in a monolithic ceiling, it is allowed to cut it out only at the junction of two concrete slabs. The arrangement of the hatch in one reinforced concrete product is unacceptable;
slabs are laid with a 2-3 cm gap.

If the length of one slab is not enough to cover the entire span, you can use one of the two available options:

lay the slabs back to back, leaving gaps at the edges of the room. At the end, the gaps will need to be filled with concrete blocks;
lay the plates not close, but at regular intervals (20-30 mm). At the end, seal the gaps with concrete, having previously fixed the formwork under the ceilings so that building mixture did not fall down.

Formwork installation

The technology of arranging the ceiling implies the mandatory use of horizontal formwork. You can rent a ready-made formwork from a specialized company, or you can assemble the necessary structure with your own hands.

The first option is simpler and more convenient. Ready-made factory formworks come with telescopic supports, which allows you to further save time on the manufacture of props.

The second option is more budgetary. For self assembly formwork, use an edged board with a thickness of at least 2.5-3.5 cm. You can use moisture-resistant plywood with a thickness of 2 cm or more.

Boards should be knocked down as tightly as possible. If there are noticeable gaps between the boards, the formwork must be covered with a waterproofing film.

Formwork set

Prepare the following fixtures for formwork assembly:

boards;
plywood;
beam;
hammer;
hacksaw;
level;
nails;
axe.

Formwork installation

First step. Install the vertical supports. The best way– adjustable telescopic metal poles. In their absence, suitable wooden logs diameter from 80 mm.

Install racks in meter increments. The distance between the walls and the posts closest to them must be at least 200 mm.

Second step. Lay crossbars over the support posts. This is a longitudinal beam, due to which the entire structure placed above will be supported.

Third step. Install the formwork on top of the crossbars. First, lay the transverse bars on the longitudinal bars. wooden beams, on them - boards or plywood.

Select the dimensions of the formwork so that its extreme edges rest against the walls without the formation of cracks.

Fourth step. The upper edge of the formwork structure must be strictly on the same level with the upper edge of the laid wall. To meet this requirement, adjust the height of the support legs.

Fifth step. Install vertical structural elements. Since the edges of the floor slab must extend into the wall, place the vertical railing at an appropriate distance from the inner edges of the walls.

Sixth step. Check the evenness of the formwork with a level. Correct deviations if found.

To connect the formwork elements, use convenient fasteners, for example, dowels or nails.

For the convenience of carrying out subsequent work, the formwork can be covered with waterproofing material.

Telescopic stands are preferred over their wooden counterparts for the reason that metal is much more durable than wood. Each telescopic pole is capable of withstanding a load of up to 2000 kg without the appearance of deformations and cracks, as can happen with a wooden beam.

Video - Installation of slab formwork

Reinforcement order

A monolithic floor slab is subject to mandatory reinforcement.

First step. Prepare armature. Select the appropriate diameter of the bars in accordance with the calculated loads. In most cases, rods with a diameter of 1.2-1.4 cm are used.

Second step. Lay the first reinforcing mesh at the bottom of the future monolithic slab. First lay the longitudinal, and then the transverse bars. Optimal size the cells of such a grid are 120-150 mm. If the overlap has a small area, you can increase the mesh size to 200 mm.

Third step. Tie the joints of the bars with steel wire.

Fourth step. Lay a second reinforcing mesh on top, similar to the first. Tie both meshes with wire.

If the length of one rod is not enough, tie an additional rod with an overlap equal to at least 40 diameters of the reinforcement. That is, if you use rods with a diameter of 12 mm, the overlap should be at least 480 mm.

concrete preparation

A standard concrete mortar is prepared for the initial pour. The recipe is the following:

2 parts of sifted clean sand;
1 part coarse aggregate - both crushed stone and gravel can be used;
1 part of cement M400-M500;
water.

Add enough water so that the consistency of the solution is close to the consistency of liquid sour cream. A thin solution will perfectly fill all the internal cavities and cracks, so that the slab will become truly monolithic.

The solution is most conveniently prepared in a concrete mixer. First, load the dry and solid ingredients, and then gradually, without ceasing to stir, add water.

In the absence of a concrete mixer, you can prepare a solution in a large trough, but this is too long and rather difficult, especially if there are no assistants.

Slab pouring

The process of pouring a monolithic ceiling can be divided into 2 stages: pouring and finishing pouring.

spilling

At this stage, the initial layer of concrete is poured. Pour the solution measuredly and slowly, sudden movements are unacceptable, because of this the formwork may be skewed.

Don't make the bleed too thick. The main task of this layer is to fill all the existing cavities.

“Smooth” the finished filling with a shovel over the entire surface. Do it smoothly and carefully. So you remove excess air and finally fill even the smallest cavities.

Finishing fill

At this stage, you need to prepare a separate solution. The recipe is the same as in the previous case. The only difference is that you need to take less water to make the concrete thicker.

First step. Pour a layer of concrete of such thickness that about 20-30 mm remain until the estimated thickness of the finished monolithic slab. Pour slowly and evenly.

Second step. Level the fill with a shovel as in the previous part of the instructions. Leave the concrete for a couple of days and proceed to the next step.

Third step. Prepare a mortar of 1 part cement and 3 parts sand. Large aggregate at this stage is not needed. Add water to obtain a solution of medium density.

Fourth step. Fill the stove to the end with the solution prepared in the previous step. In the process of pouring, level the slab with a rule until a perfectly smooth surface is obtained.

This completes the pouring of the monolithic floor. You will only have to monitor the state of the pour for some time so that the concrete hardens and gains strength without any problems.

Concrete care after pouring

During the curing process, the concrete will release a large number of heat, under the influence of which intensive evaporation of moisture will begin. Lack of moisture will cause the concrete to crack. Therefore, during the first few days after pouring, you will need to regularly moisten the slab with water.

You can pour water in buckets (2-3 buckets per run) or through a hose with a sprayer. You can first lay old rags (preferably burlap) on dried concrete and pour water on them. In hot weather, cover poured concrete with polyethylene, because. Too fast drying may cause the board to crack.

Formwork can be removed approximately 10 days after the last wetting. In general, the plate will gain strength in 3-5 weeks. After this period, it will be possible to proceed to the implementation of further planned construction work.

Thus, it is possible to independently equip a monolithic ceiling. At the same time, you will spend much less money on arranging the necessary structures than in the case of buying prefabricated prefabricated slabs. Follow the instructions and you'll be fine.

Successful work!

Video - Do-it-yourself monolithic overlap

A strong and reliable partition between floors is very important element construction, to create it, a concrete floor is made. A monolithic concrete slab has several undeniable advantages over prefabricated traditional slabs. You should start with the fact that the creation of such an overlap does not require the use of a lifting edge, which greatly saves financial and time resources. Everything can be done with your own hands, from heavy equipment you only need a concrete pump, but its use is not mandatory. In addition, it is not difficult to make concrete floors with your own hands, it should be noted their sound-absorbing and heat-insulating properties.

Concrete floor plan.

If you make such a design correctly, then you can count on the fact that extraneous sounds will not bother, this is the difference from drywall partitions. And walk in a new way concrete floor very nice, while not creating the feeling of a swaying ship deck.

Materials and tools

In order to get started, you will need the following materials:

In order to carry out a concrete floor, you need a concrete solution.

moisture resistant plywood, the thickness of which does not exceed 15-20 mm;
bars and beams made of wood (they will need to be laid under plywood);
supporting racks;
concrete mortar;
in order to create a frame, you will need knitting wire and fittings.

Of the tools you will need:

jack;
concrete pump (its use is optional);
spirit level or level;

Frame and formwork

Scheme of formwork for concrete floor.

Construction should begin with the creation of formwork, while the appearance of cracks and different kind holes. Then you need to make sure that the jacks and racks under the formwork are firmly installed. This is a serious issue because we are talking about safety. Formwork is best made from moisture-resistant plywood (20 mm laminated material for this fit better Total). The formwork must be very strong, since the weight of liquid concrete is 500 kg / sq.m, if the layer thickness is 200 mm. Formwork must be done not only over the area of \u200b\u200bthe room, but also around the perimeter so that the concrete mix does not flow out of the limits.

Now we need to form the frame. It is made from wire, reinforcement using special hooks, a mesh is obtained with a mesh size of 1.5 by 1.5 cm (you can make 2 by 2 cm). As for the diameter of the reinforcement for the main frame, it should be 15-20 mm. When the frame is made, it should be carefully checked for strength before proceeding with the pouring of concrete. From the type of reinforcement, you need to calculate the step that will be provided during installation. When the step is calculated, the total load on the concrete floors must also be taken into account.

The lower layer of reinforcement is laid across the bottom of the formwork, and not parallel to the span, so that the ends of the reinforcement rest on the supporting beams. The fact is that it is on these beams that reinforcement should be laid, since it is this factor that largely determines the success of construction. The next layer of reinforcement is laid perpendicular to the previous one. After all the reinforcement has been laid in an appropriate way, it is necessary to securely fix all the points of contact of the perpendicular rows of reinforcement with wire. Then the bearing beams will be reliable and of high quality.

Concrete beams connected to the foundation are better than antiseptic wooden beams, since beams made of wood deteriorate faster.

Concreting process

The next step is concreting, here it is very important to fill very quickly. The binder in the concrete solution is cement, the fillers are crushed stone and sand. It is necessary to fill the formwork with concrete not in one go, but it is necessary to maintain one direction. Concreting can be done manually, you can use a concrete pump. The concrete mixture is poured without interruption, then it is compacted with the help of internal vibrators so that voids do not form in the thickness of the concrete layer. All irregularities of the base should be controlled with a spirit level or level. To find out how thick the plate turned out, you need to use a probe. It must be borne in mind that the plate must be strong enough, this factor is very important.

Scheme of concreting.

While the concrete mortar hardens, it must be protected from direct sunlight. Wind and draft also have on him Negative influence. Any kind of mechanical impact experienced by concrete slab until it has hardened, is also not allowed. In order for the concrete slab to harden in favorable conditions, it is necessary to water it from time to time, this procedure must be done within a week. The slab remains with the formwork until it dries completely.

In order for the concrete floors to be made in-house high level, it is necessary in their manufacture to use materials only of the High Quality. As for the mortar for pouring concrete, it is better to use M-250 or M-400 concrete for this, such material incorporates special heavy fillers. An important milestone such work is to carry out all the necessary calculations, so you can save a lot of money.

In order for the calculations to be carried out with maximum accuracy, it is necessary to compare two main parameters - the strength of the reinforcement manufacturing and the mass that acts on the slab. For monolithic systems, the following factors are determined: the rigidity of the longitudinal axis, the magnitude of the forces in the most loaded sections of the floor, the force of daily loads on the slab.

Making concrete floors with your own hands also has the advantage that you can independently think through and lay all plumbing communications. In order for the plate to have good thermal insulation characteristics, you need to use boards. Before laying, the slab can be leveled with self-leveling compounds.

According to the forum member ontwerper from Moscow, it is not so difficult to do it on your own. He cites well-known and little-known considerations for their manufacture as arguments. In his opinion, making overlaps with your own hands is beneficial for several reasons:

Availability of technologies and materials;
Convenience and practicality from an architectural and engineering point of view;
Such floors are durable, fireproof and have soundproofing qualities;
financial feasibility.

Monolithic works

Before pouring concrete, ontwerper advises to carefully consider the whole process and, first of all, order concrete from the factory. It is better than home-made - there is a quality control and quantity of fillers that improve concrete and prevent it from delamining for a long time. The composition should consist of heavy aggregates, have a strength class of B20-B30 (M250-M400), and frost resistance of F50.

Do not be lazy and check the vacation parameters, class-mark and time until the moment of concrete setting according to the documents.

If you need to supply concrete to the second, third floor or over a long distance, then you will not be able to do this without a concrete pump, and rolling concrete with shovels along endless chutes is a very difficult and inconvenient task.

IN winter time concrete can be ordered from antifreeze additives, given that additives usually increase the curing time, some of them provoke corrosion of the reinforcement, but this is acceptable if the additive is factory-made.

ontwerper prefers not to build in the winter, and does not recommend it to you. IN last resort do not prepare the solution yourself, use factory concrete.

Formwork installation

The main purpose of the formwork is to withstand the mass of freshly poured concrete and not deform. To calculate the strength, you need to know that one 20 cm layer of concrete mix presses on square meter formwork with a force of 500 kg, to this you need to add the pressure of the mixture when it falls from the hose, and you will understand that all structural elements must be reliable.

For its manufacture, ontwerper advises using 18-20mm plywood laminated (coated) or plain (but it sticks more strongly). For beams, crossbars and formwork props, a bar with a thickness of at least 100x100 mm should be used.
After its assembly, it is necessary to check the horizontalness of all structures. Otherwise, in the future you will lose a lot of time and money to correct errors.

Reinforcement

The lower one is along the span, the lower one is across the span, the upper one is across the span, the upper one is along the span.

span- the distance between the supporting walls (for a rectangular slab along the short side). The lowest row is laid on plastic crackers specially designed for this, their height is 25-30mm. Top row- overlaps it across and knits with wire at all intersections.

Then next in line is the installation of a mesh separator - parts from reinforcement with a certain step, it can be done as you wish. On the dividers - the top across, - knit, on it the top along, - knit with wire at all intersections. The top point of the frame (the top of the top rod) should be 25-30 mm below the top edge of the formwork wall, or the concrete thickness is higher top reinforcement by 25-30 mm.

After the completion of the reinforcement, the frame must be a rigid structure that must not move when concrete is poured from the pump. Before pouring, check the compliance of the pitch and diameter of the reinforcement with the project.

Pouring concrete

After all the preparation, you need to take and distribute the concrete over the entire area, vibrate it. It is best to pour the entire slab at a time, if this is not possible, put cuts - intermediate walls inside the formwork contour, limiting concreting. They are made of a steel mesh with a cell of 8-10 mm, setting it vertically and attaching it to the frame reinforcement. In no case do cuts in the middle of the span and do not make them from the board, PPS.

Curing

After pouring the slab, it must be covered to prevent rain from entering, and the outer surface should be constantly watered to keep it moist. After about a month, the formwork can be removed, and in case of emergency, this can be done no earlier than a week later and only the panels can be removed. To do this, you need to carefully remove the shield, and support the plate back with a stand. Racks support the plate until it is fully ready, about a month.

Strength of a monolithic floor: calculation

It boils down to comparing two factors:

Forces acting in the plate;
The strength of its reinforced sections.

The first must be less than the second.

Walls on a monolithic floor slab: we calculate the load

Let's make calculations of constant loads on a monolithic floor slab.

Self-weight of a monolithic floor slab with a load safety factor of 2.5t/m3 x 1.2 =2.75t/m3.
- For slab 200mm - 550kg/m3

Own weight of the floor with a thickness of 50mm-100mm - screed - 2.2t/m2 x 1.2= 2.64t/m3
- for floor 50mm - 110kg/m3

Brick partitions with a size of 120 mm lead to the area of the slab. The weight of 1 running meter of a partition 3m high is 0.12m x1.2x1.8 t/m3 x 3m = 0.78t/m, with a step of partitions 4m long, approximately 0.78/4= 0.2t/m2. Thus, the reduced weight of the partitions = 300 kg/m2.

Payload for 1st group limit states(strength) 150kg / m3 - housing, taking into account the reliability factor of 1.3, we accept. Temporary 150x1.3 = 195kg/m2.

The total design load on the slab is 550+110+300+195=1150kg/m2. We will accept for sketch calculations the load in - 1.2t / m2.

Determination of moment forces in loaded sections

Bending moments determine 95% of the reinforcement of bending plates. Loaded sections are the middle of the span, in other words, the center of the slab.

Bending moments in a slab of reasonable thickness, square in plan, hinged - not pinched along the contour (on brick walls) for each of directions X,Y can roughly be defined as Mx=My=ql^2/23. You can get some values for special cases.

Slab in terms of 6x6m - Мх=My= 1.9tm;
Slab in terms of 5x5m - Mx=My= 1.3tm;
Slab in terms of 4x4m - Мх=My=0.8tm.

These are forces that act both along and across the slab, so you need to check the strength of two mutually perpendicular sections.

Strength test to the longitudinal axis

When checking the strength to the longitudinal axis of the section according to the bending moment (let the moment be positive, i.e. belly down), the section has compressed concrete from above and tensile reinforcement from below. They form a power pair, perceiving the moment force coming to it.

Determining the force in this pair

The height of a pair can be roughly defined as 0.8h, where h is the height of the slab section. The force in the reinforcement is defined as Nx(y)=Mx(y)/(0.8h). We get in the representation of 1 m of the width of the slab section.

Slab in terms of 6x6m -Nx(y)= 11.9t;
Slab in terms of 5x5m - Мх=My= 8.2t;
Slab in terms of 4x4m - Mx=My= 5t.

Under these efforts, select reinforcement of class A-III (A400) - a periodic profile. The design tensile strength of reinforcement is R=3600kg/cm2. sectional area of a reinforcing bar with a diameter Ф8=0.5cm2, Ф12=1.13cm2, Ф16=2.01cm2, Ф20=3.14cm2.

The bearing capacity of the rod is Nst=Ast*R F8=1.8t, F12=4.07t, F16=7.24t, F20=11.3t. From here you can get the required reinforcement pitch. Step= Nst/ Nx(y)

Slab in plan 6x6m for fittings Ф12 Pitch=4.07t/ 11.9t=34cm;
Plate in terms of 5x5m - for fittings F8 Pitch = 1.8 / 8.2 = 22cm;
Slab in plan 4x4m - Ф8 Step=1.8/5=36cm.

This is strength reinforcement in each of the X and Y directions, i.e. a square mesh of bars in the tension zone of concrete.

In addition to strength, it is necessary to reduce the formation of cracks. For slabs of houses and residential premises with a span of up to 6 m, 200 mm thick, supported along the contour (i.e., on four sides), at any ratio a / b, it is possible to accept the lower working reinforcement from A III rods in two directions with a step of 200x200 with a diameter of 12 mm, the upper ( constructive) - the same from F8, thinner and less does not follow.

All this is a special case of a general approach that demonstrates the specifics of the task, but for its implementation it is necessary to look deeper and turn to specialists.

Posted by FORUMHOUSE ontwerper.

Editor: Roman Adamov

Construction of two-storey residential buildings is a costly business. But at some stages you can save money, especially if there are helpers. According to experts, do-it-yourself monolithic interfloor overlapping is quite beneficial for the following reasons. Firstly, it is the availability of materials and technologies: it is not a problem to purchase concrete of any brand and in any quantity today. Secondly, a do-it-yourself monolithic floor slab can be made very high quality even without the help of professionals. But with some nuances of this case, before starting work, it is still necessary.

It is better to order concrete at the factory: its preparation on their own- the occupation is quite laborious, and besides, with industrial production the quantity and quality of fillers are controlled. ready concrete must correspond to the strength class of grades M250 ... M400 with frost resistance not lower than F50.

When buying, you must check the accompanying documents, which should indicate the most important characteristics of the material.

If the pouring of a monolithic ceiling will be carried out on the second floor or higher, it is better to use a gasoline pump: it is very difficult and long to carry concrete in buckets or distill it along long gutters. To fill the floor in winter, it is necessary to use special additives that increase the curing time, but it is better to wait for the warm season.

Formwork manufacturing

Formwork must be strong enough to withstand the mass of freshly poured concrete without visible deformation. During its construction, it must be taken into account that 200 mm of concrete (in thickness) exerts a pressure on the formwork material equal to 500 kg. In addition, pouring out of the hose, the mass of concrete exerts additional pressure on the material, so additional strength must be incorporated into the formwork design.

It is better to make formwork from plywood sheets 18 ... 20 mm thick, while it is desirable that it be laminated: such a surface will then be easier to clean. In some cases, it is laid on the bottom of the formwork waterproofing material, which is used as a thick polyethylene film or only. A bar with a section of 100 × 100 mm is suitable as supports, struts, racks and beams.

The site to be poured with concrete must be strictly horizontal, otherwise it cannot be avoided. additional costs time and money to correct the error.

Reinforcement

This process is carried out in order to obtain a durable floor slab. For this purpose, reinforcement with periodic profiling of the A400, A500 or AIII type is used. It is laid in four rows: the bottom row is located along the span, the next one is across, then again a row of reinforcement is laid in the same direction, and the top one is again in the longitudinal direction. The span is the distance between the bearing walls, which are located on the short sides of a rectangular building.

The lower row of reinforcement is placed on plastic crackers, designed to create a gap of 25 ... 30 mm between the bottom of the formwork and the metal. The next one is placed on top of the bottom row, after which they are tied together with soft wire at the intersections. The next detail is the mesh separator: it is designed to create the necessary distance between the upper and lower reinforcement. In this case, the concrete is poured in such a way that its upper level is higher than the reinforcement by the same 25 ... 30 mm.

The reinforcing frame must be a rigid structure, which must be stationary during the pouring of the mixture.

Pouring concrete

After graduation preparatory work filling is performed directly. In this case, the concrete must be distributed evenly over the entire area of \u200b\u200bthe formwork so that its layer is the same in all places. To get rid of air bubbles, it must be vibrated using a special device. It is allowed to repeatedly pierce the mixture with a bayonet shovel, but there is a risk of damage to the waterproofing film.

The process is best carried out in one go, but if the overlap area is large or it is impossible for other reasons, then the so-called “cuts” are mounted (grids with cells up to 10 mm made of steel wire). They are installed vertically and attached to the frame reinforcement. In the middle part of the span, cuts are not allowed. Boards, plywood and other similar materials are not used for this.

After the concrete is poured, it must be covered with a film: this will prevent it from cracking. In addition, the concrete should be moistened so that it gains strength gradually. in a month: during this time, the floor slab will finally harden.

During the construction of the house, you can not do without installing the ceiling. This design limits the height of the room, insulates it from the penetration of cold air in winter, and takes on the load from the roof or upper floor. IN modern technologies most often use a plate reinforced with reinforcement.

Description of types, design features, technical requirements

Depending on the location and functional purpose of concrete floors, there are several types:

basement;
interfloor;
attic;
attic.

According to another classification, they are divided into solid and prefabricated. The first are made independently, pouring the mixture onto the prepared reinforcing cage. This method does not require the use of a crane to lift the slabs, but additional hands will be needed to install the formwork, tie the frame, and pour the concrete.

Prefabricated systems are obtained by laying standard panels of the desired size. By execution, they are of three types: monolithic, ribbed, hollow. In private construction, the third option is more often used. Product dimensions: length - up to 7 m, width - 1.5, height - 0.22.

Considering the operating conditions, the following requirements are imposed:

strength and rigidity exceeding the calculated load (it is defined as the total weight of the slab itself, screed, furniture, and other things);
high level of sound insulation;
fire resistance;
the thickness of the walls for concrete blocks is not less than 200 mm.

Concrete has a high thermal conductivity, to reduce which it is recommended to insulate, for example, with mineral wool.

Installation instructions

Laying a finished concrete floor with your own hands helps preliminary preparation buildings and slabs.

Scheme of preparatory work

1. To ensure that the panels are in the same plane, the upper end of the load-bearing walls is checked for horizontality. This can be done in this order: 30-40 cm before the end of the masonry, markers are applied to the wall using a laser or liquid level, and then the finishing brick rows are checked with a tape measure. The top row is positioned so that the bricks are oriented inside the room.

2. Most often, the edge of the box is aligned differently - the perimeter of the upper edge of the walls with reinforcement is concreted. Due to this, the brick or block structure is additionally strengthened. At a certain level, the masonry leaves an unfilled space for the armored belt. The depth of support (overlap) of the ceiling depends on the total thickness of the slab together with the thermal insulation. Usually the panel goes into the wall by 70-120 mm.

The scheme of pouring the armored belt is similar to laying the foundation: the formwork is mounted, inside it a frame is made of reinforcing bars by welding, the mixture is poured without crushed stone. The design of the belt for the plinth is made faster: they simply put additional formwork along the outer edge of the foundation.

3. Before installing the plates, the voids in their ends must be closed. If this is not done, placing the top floor wall on the edge of the floor may cause it to collapse. Concreting of inter-slab joints will not work: the mixture will flow into the holes. It is not difficult to close the cavity - a half-brick is inserted into it and sealed with a solution.

4. Prepare a platform for lifting equipment. This is a site with dense soil, otherwise the crane will get stuck in soft soil. To ensure its stability, temporary placement of road panels on the site is practiced. It is advisable not to install a crane near the pit in order to prevent the collapse of the soil or the sliding of heavy equipment.

Laying technology

It will not be possible to install the ceiling yourself; three installers usually participate in the process. One worker connects the plates, the other two correct them when lowered.

1. A sufficiently thick layer is applied to the reinforced belt. concrete mix(layer thickness not less than 2 cm).

2. The crane operator lowers the panel, holding it by pulling on the sling ropes. In a suspended position, it is easily moved in the right direction with the help of a crowbar.

3. Compensation propyl. It is necessary if several spans are covered with one slab. Conventional structures work in bending and must rest on two short ends. If intermediate supports are placed, tensile stresses occur in the upper part of the floors. Since there is no reinforcement there, cracks can appear. To relieve stress, a groove is sawn with a grinder, placing it above the intermediate support. Subsequently, a crack will appear at the site of the slot.

4. Anchoring. This is a firmware with reinforcing wire: it is threaded through the mounting eyes, pulled together, and then welded. The scheme is usually laid down in the project, if it is not there, the standard version is used. Load-bearing walls have at least 1 anchor for every 3 running meters, on non-bearing anchors are removed from all extreme loops. The end plates are sewn with diagonal anchors.

Inter-tile gaps (rusts) are poured with concrete mortar, due to which the structure becomes monolithic and durable.

During installation, sometimes you have to adjust the dimensions. The optimal overlap on the wall is no more than 120 mm, and the maximum allowable value is 250. With an increase in this parameter, the scheme of operation of the floor changes, as a result, cracks may appear on it. The panels are shortened in the following way:

they outline the cutting line, put a bar under it - its thickness should be such that the edge to be separated is in weight;
according to the marking, an incision is made with a grinder, concrete is split with a sledgehammer above and below the voids;
break barriers;
the metal reinforcement is cut with a grinder, leaving a couple of millimeters - this residue is smashed with a sledgehammer (otherwise the stressed reinforcement may pinch the grinder's disc).

If the size is insufficient, the gap near the wall is bricked up.

How to make your own cover?

The frame is made from edged board(thickness 25-35 mm), plywood (thickness from 20 mm) or rent.

1. Install the formwork. Its dimensions should be such that the edges rest against the walls without gaps. The position of the structure is checked using a level. Cover it with waterproofing film.

2. Reinforce. Usually, rods with a diameter of 12-14 mm are taken for the frame. First, longitudinal and then transverse elements are laid (cell 12-15 cm), tied with wire. In the same order, the upper mesh of the frame is made, the joints of the bars are staggered, the ends of the rods are placed on the supporting beams.

3. Preparation of concrete. Volumetric proportions of its components:

sifted sand - 2 parts;
crushed stone (gravel) - 1 part;
cement M400 (500) - 1 part;
water.

Water is poured so much that the solution resembles liquid sour cream in density.

4. Fill. Carefully fill all cavities with the mixture, “stroke” with a shovel, removing air. For finishing pouring, a thicker mixture is made, laid down. The thickness of the layer is 2-3 cm less than the final size of the overlap. After a couple of days, the seized composition is covered with a cement-sand mortar of medium density, leveled with a rule to an ideal plane.

The hardening monolith is periodically watered with water, covered with a film in the heat. On the 10th day, the formwork is removed, allowed to gain strength within 3-5 weeks. After that, you can proceed to the next stage of construction.