Homemade floor slabs with their own hands. How to pour a monolithic floor slab. Scheme of laying floor slabs

Ceilings in brick, block and concrete houses in most cases they are made of reinforced concrete (learn more about). It is these structures that can guarantee the strength, reliability and durability of the structure. Most of the floors are reinforced concrete slabs laid in a certain order. Laying is carried out by several workers using a crane. However, there are times when the use of a crane is not possible or the structure has a non-standard shape. In this case, a monolithic reinforced concrete floor is created. In addition, in some situations monolithic overlap may be the most cost effective option.

The process of pouring a monolithic ceiling is quite complicated, and only professionals can do some of the steps. Studying the technology of creating a monolithic floor slab will allow you to independently perform most of the work and control the construction moments when the work is done by hired people.

Formwork creation

A monolithic slab is poured into a horizontal formwork, which can be made independently or purchased ready-made version. The use of ready-made formwork provides two advantages: the first is that the structure is collapsible, and the second is that it comes with telescopic supports. With their help, the formwork is installed at the same level.

By the way, earlier we considered, .

However, many private developers prefer do-it-yourself formwork. In this case, it is recommended to adhere to the following rules:

For manufacturing, it is necessary to take an edged board with a thickness of 25-35 mm or sheets of plywood with a thickness of 20 mm. In the first case, it becomes necessary to tightly fit the boards to each other, and if there are gaps, it is recommended to use a waterproofing material. Plywood sheets allow you to get a more even surface, while the risk of cracks is minimized.
Vertical racks can be made from timber or logs with a diameter of 8-15 cm. Install supports at a distance of 1 meter from each other and 20 cm from the walls. The height of the posts is adjusted according to the height of the wall, the upper edge of the formwork and the upper edge of the wall must be at the same level.
Crossbars are laid on top of the racks. For this purpose, a beam, I-beam or channel is suitable.
Horizontal formwork is laid directly on the crossbars. First there are transverse beams, then plywood or boards.
Installation vertical parts formwork is carried out taking into account the approach to the walls by about 15-20 cm. Therefore, the vertical fence of the slab should be located at such a distance from the inner level of the wall.
The horizontality of the formwork and its even position is determined using a building level or level.

Rules for reinforcing a monolithic floor slab

The creation of a reinforcing frame can be called one of the crucial moments (read about in detail), therefore, when performing the process, it is important to follow a few rules:

The best option for reinforcing the floor slab is hot-rolled steel reinforcement class A3 with a diameter of 8-14 mm.
The reinforcement is recommended to be laid in two layers: the first is placed in the lower part of the slab, the second - in its upper part. At the same time, it is necessary to create a gap of 20-25 cm from the lower and upper edges of the ceiling. For this purpose, special plastic clamps are used, which are preferably installed at the junctions of the reinforcement rods.
The distance from the formwork walls to the outer bars of the reinforcement must be more than 2 cm. However, it should be remembered that the mesh of the reinforcement must necessarily go onto the walls. Moreover, if the walls are built of brick, then the overlapping distance can be more than 15 cm, the mesh can go on walls of aerated concrete blocks by 25 cm or more.
For knitting rods, use a special knitting wire.
The mesh size of the reinforcing mesh depends on the floor area. Standard dimensions are 15*15cm, for floors small size you can use grids with cells of 20 * 20 cm.
With insufficient length of the rod, you can build up. In this case, an overlap should be made, the length of which is approximately equal to 40 rod diameters.

Self-preparation and pouring of concrete solution

To create a monolithic floor, you can prepare a concrete solution using standard technology. Her recipe contains the following ingredients:

Screened river sand.
Crushed stone or gravel.
Cement brand M400 or M500.
Water.

The material should be taken in a certain proportion, which most often looks like this: 1 part of crushed stone and 2 parts of sand are taken for 1 part of cement (we considered separately). To prepare the solution, all components are mixed in dry form, then water is added in small portions. The finished mixture should resemble thick sour cream in consistency. It is easier and faster to knead the concrete solution in a concrete mixer, but if it is not available, you can take a large trough and invite several assistants.

poured monolithic slab covering in two stages:

First you need to shed the reinforcing cage. At this stage, great care should be taken, the supply of concrete should be carried out in small batches, without sudden movements. Otherwise, you can deform formwork structure. The fill should not be too thick. The main goal at this stage is to achieve maximum filling of all cavities. After pouring, the concrete is carefully pierced in several places with a rebar or shovel to remove excess air and allow the mortar to penetrate into unfilled places. Then gently smooth the surface.
The second stage involves finishing pouring, which will require concrete of a thicker consistency. The recipe for preparing the solution remains the same, only water is taken in a smaller volume. The final filling is carried out in several stages. First, a layer of small height is slowly and evenly poured. It should not reach the edge of the formwork by 2-3 cm. Perform alignment concrete surface and leave the structure to set. Then a solution of medium density is prepared, for which they take water, one part of cement and three parts of sand. The slab is poured with the finished solution to the upper edge of the formwork and leveled with a rule, trying to achieve a perfectly smooth and even surface.

Using beacons for pouring concrete mortar

After finishing pouring, the surface concrete slab overlap should acquire perfect evenness. For this purpose, you can use beacons that are set at a certain level. The distance between the beacons should correspond to the width of the rule, that is, about one and a half meters. When placing beacons, they use the building level, periodically checking the correct installation.

Rules for the care of concrete during the hardening period

It is possible to achieve a high-quality result when pouring a monolithic floor slab if the concrete is properly cured.

The curing concrete solution emits a large number of heat, which leads to a strong evaporation of moisture from the surface. As a result, concrete begins to crack and its strength characteristics are significantly reduced. Regular watering of the concrete surface with water in the first two to three days helps to solve the problem. pour water on exposed concrete not recommended, so you can first cover it with old rags or burlap.

Roast summer time can cover the surface plastic wrap, which will also prevent strong evaporation.

Concrete dries for a long time, it takes a certain time to achieve a certain strength:

Concrete gains 30% strength in three days.
About 80% strength - after two weeks.
Full strength is achieved after 28 days.

We considered this issue in more detail in the article.

To check, you can use the following method: roofing material is placed on the concrete and left overnight. If in the morning a dark spot formed under it, then the concrete has not dried out yet.

The formwork structure begins to be dismantled after 10-15 days after the last watering, however, proceed to further construction work only after the concrete has reached its full strength.

The construction of a monolithic floor slab requires a lot of effort, patience and time; an easier way is to purchase ready-made reinforced concrete slabs. However, it should be noted that the second option requires significant material costs. Concerning self-manufacturing, then in this case you can get both material benefits and construction experience. The main condition is to follow the rules and follow certain instructions.

In houses made of brick, concrete or concrete blocks, floors are usually made of reinforced concrete. They provide exceptional strength and seismic resistance of the structure, and are also very durable and do not burn, which is important. There are several ways to arrange reinforced concrete floors. The most common and versatile is laying prefabricated floor slabs. Such slabs are ordered at reinforced concrete factories, and then mounted with a crane and a team of workers. In the same cases, when the use of a crane on a construction site is difficult, or when the house has non-standard layout and it is difficult to lay out the finished slabs, a monolithic floor slab is being equipped. In fact, you can pour a monolithic slab not only when there are indications for this, but also simply because you consider it more appropriate. In this article we will tell you how to lay floor slabs and how to pour a monolithic slab. Not all work can be done independently, but it is still worth familiarizing yourself with the technology, if only in order to control the process at the construction site.

Do-it-yourself monolithic floor slab

A monolithic floor has a number of advantages compared to a floor made of prefabricated reinforced concrete slabs. Firstly, the construction is solid and monolithic without a single seam, which provides a uniform load on the walls and foundation. Secondly, a monolithic fill allows you to make the layout of the house more free, as it can be based on columns. Also, the layout can imply as many corners and nooks as you like, for which it would be difficult to pick up floor slabs. standard sizes. Thirdly, it is possible to safely equip a balcony without an additional support plate, since the structure is monolithic.

You can equip a monolithic floor slab yourself; this does not require a crane or a large team of workers. The main thing is to follow the technology and not save on materials.

Like everything related to construction, a monolithic ceiling begins with a project. It is advisable to order the calculation of a monolithic floor slab in the design office and not save on it. It usually includes the calculation of the cross section of the plate for the action of the bending moment at maximum load. As a result you will get optimal dimensions for a floor slab specifically in your home, instructions on which reinforcement to use and what grade of concrete. If you want to try to perform the calculations yourself, then an example of calculating a monolithic floor slab can be found on the Internet. We will not focus on this. Consider the variant when the usual country house with a span of no more than 7 m, so we will make a monolithic floor slab of the most popular recommended size: from 180 to 200 mm thick.

Materials for the manufacture of a monolithic floor slab:

Formwork.
Supports for supporting the formwork at the rate of 1 support per 1 m2.
Steel fittings with a diameter of 10 mm or 12 mm.
Concrete brand M 350 or separately cement, sand and crushed stone.
Bending fixture for fittings.
Plastic coasters for fittings (clamps).

Technology of pouring a monolithic floor slab includes the following steps:

Calculation of the floor slab, if the span is more than 7 m, or the project involves the support of the slab on the column / columns.
Installation of formwork type "deck".
Reinforcement of the slab with steel bars.
Pouring concrete.
Compaction of concrete.

So, after the walls are driven to the required height, and their level is almost perfectly aligned, you can proceed to the arrangement of a monolithic floor slab.

The device of a monolithic floor slab assumes that the concrete will be poured into a horizontal formwork. Sometimes horizontal formwork is also called a "deck". There are several options for its arrangement. The first - rental of ready-made removable formwork from metal or plastic. Second - formwork production on site using wooden planks or sheets of moisture resistant plywood. Of course, the first option is simpler and preferable. Firstly, the formwork is collapsible. Secondly, it offers telescopic supports, which are needed to support the formwork on the same level.

If you prefer to make the formwork yourself, then please note that the thickness of the plywood sheets should be 20 mm, and the thickness of the edged boards 25 - 35 mm. If you knock down shields from edged boards, then they need to be tightly fitted to each other. If gaps are visible between the boards, then the surface of the formwork should be covered waterproofing film.

Formwork is installed in this way:

Vertical poles are installed. These can be telescopic metal racks, the height of which can be adjusted. But you can also use wooden logs with a diameter of 8 - 15 cm. The step between the posts should be 1 m. The posts closest to the wall should be located at a distance of at least 20 cm from the wall.
Crossbars are laid on top of the racks (a longitudinal beam that will hold the formwork, an I-beam, a channel).
Horizontal formwork is laid on the crossbars. If not ready-made formwork is used, but self-made, then transverse beams are laid on top of the longitudinal bars, on which sheets of moisture-resistant plywood are placed on top. The dimensions of the horizontal formwork must be perfectly adjusted so that its edges rest against the wall without leaving gaps.
The height of the support-racks is adjusted so that the upper edge of the horizontal formwork coincides with the upper edge of the wall masonry.
Installed vertical elements formwork. Taking into account the fact that the dimensions of a monolithic floor slab should be such that its edges go onto the walls by 150 mm, it is necessary to make a vertical fence at exactly this distance from the inner edge of the wall.
For the last time, the horizontal and even arrangement of the formwork is checked using a level.

Sometimes, for the convenience of further work, the surface of the formwork is covered with a waterproofing film or, if it is made of metal, lubricated with machine oil. In this case, the formwork can be easily removed, and the surface of the concrete slab will be perfectly flat. The use of telescopic props for formwork is preferable to wooden supports, as they are reliable, each of them can withstand a weight of up to 2 tons, microcracks do not form on their surface, as can happen with wooden log or a bar. Renting such racks will cost about 2.5 - 3 USD. per 1 m2 of area.

After the arrangement of the formwork, a reinforcing cage of two meshes is installed in it. For the manufacture of the reinforcing cage, steel reinforcement A-500C with a diameter of 10 - 12 mm is used. From these rods, a mesh with a mesh size of 200 mm is connected. To connect the longitudinal and transverse rods, a knitting wire of 1.2 - 1.5 mm is used. Most often, the length of one reinforcing bar is not enough to cover the entire span, so the bars will have to be connected along each other. To make the structure strong, the rods must be connected with an overlap of 40 cm.

The reinforcing mesh should go onto the walls at least 150 mm if the walls are made of brick, and 250 mm if the walls are made of aerated concrete. The ends of the rods should not reach the vertical formwork along the perimeter by 25 mm.

Reinforcement of a monolithic floor slab is carried out using two reinforcing mesh. One of them - the bottom one - should be located at a height of 20 - 25 mm from the bottom edge of the plate. The second - top - should be located 20 - 25 mm below the top edge of the plate.

In order for the lower grid to be located at the desired distance, special plastic clips. They are installed in increments of 1 - 1.2 m at the intersection of the rods.

The thickness of a monolithic floor slab is taken at the rate of 1:30, where 1 is the thickness of the slab, and 30 is the span length. For example, if the span is 6 m, then the thickness of the slab will be 200 mm. Given that the grids should be located at a distance from the edges of the slab, the distance between the grids should be 120 - 125 mm (from the thickness of the slab of 200 mm we subtract two gaps of 20 mm and subtract 4 thicknesses of reinforcing bars).

In order to separate the grids at a certain distance from each other, 10 mm reinforcing bars are made using a special bending tool. special clamps - stands as in the photo. The upper and lower shelves of the latch are 350 mm. Vertical dimension latch is 120 mm. The installation step of the vertical clamps is 1 m, the rows should be staggered.

The next step - end stop. It is installed with a step of 400 mm at the ends of the reinforcing cage. Serves to strengthen the support of the plate on the wall.

Another important element - upper and lower mesh connector. How it looks, you can see in the photo. It is necessary so that the spaced grids perceive the load as a whole. The installation step of this connector is 400 mm, and in the zone of support on the wall, within 700 mm from it, with a step of 200 mm.

pouring concrete

Concrete is best ordered directly from the factory. This greatly simplifies the task. In addition, pouring the mortar from the mixer in an even layer will ensure exceptional strength of the slab. What can not be said about the stove, which was poured by hand with breaks to prepare a new portion of the solution. So it is better to pour concrete immediately with a layer of 200 mm, without interruptions. Before pouring concrete into the formwork, it is necessary to install a frame or boxes for technological openings, for example, a chimney or ventilation duct. After pouring, it must be vibrated with a deep vibrator. Then leave to dry and gain strength for 28 days. The first week the surface must be moistened with water, only moistened, and not filled with water. After a month, the formwork can be removed. The monolithic floor slab is ready. For the installation of floor slabs, the price includes the cost of reinforcement, concrete, formwork rental and the order of a mixer machine, as well as a concrete pump. In fact, it comes out to about 50 - 55 USD. per m2 of flooring. How the floor slab is poured with concrete can be seen in the video demonstrating the installation of floor slabs.

How to properly lay floor slabs

The use of factory-made monolithic reinforced concrete floor slabs is considered more traditional. PC slabs are more popular - slabs with round voids. The weight of such slabs starts from 1.5 tons, so laying floor slabs with your own hands is impossible. A crane is required. Despite the seeming simplicity of the task, there are a number of nuances and rules that must be observed when working with floor slabs.

Rules for laying floor slabs

The factory-made floor slab is already reinforced at the factory and does not require additional reinforcement or formwork. They are simply laid in the span with leaning on the walls, following some rules:

The span should not be more than 9 m. It is this length of the slab that is the largest.
Unloading and lifting of plates is carried out with the help of special equipment provided by the project. To do this, there are mounting loops in the plates, for which the mounting slings are hooked.
Before laying floor slabs, the surface of the walls on which they will be laid must be leveled. Large height differences and distortions are not allowed.
The slabs should rest on the walls by 90 - 150 mm.
It is impossible to lay the slabs dry, all cracks and technological seams must be sealed with mortar.
The location of the plates must be constantly monitored relative to the walls and supporting surfaces.
Plates are laid only on load-bearing walls, all piers are equipped only after the installation of ceilings.
If you want to cut a hatch in the ceiling, then it must be cut at the junction of two plates, and not in one plate.
The slabs should be placed as close as possible to each other, but with a gap of 2 - 3 cm. This will ensure seismic resistance.

If there are not enough floor slabs to cover the entire span, and, for example, 500 mm remains, then there are different ways laying floor slabs in this case. The first is to lay the slabs back to back, and leave the gaps along the edges of the room, then close the gaps with concrete or cinder blocks. The second - laying plates with uniform gaps, which are then sealed concrete mortar. To prevent the solution from falling down, a formwork is installed under the gap (a board is tied up).

Floor slab laying technology

In the process of laying floor slabs, there should be clear coordination between the crane operator and the team receiving the slab. To avoid injuries on the construction site, as well as to comply with all technological process and the rules described in SNiPs, the foreman at the construction site must have routing floor slab installation. It indicates the sequence of work, the number and location of equipment, special equipment and tools.

It is necessary to start laying the floor slabs from the flight of stairs. After laying the plates, their location is checked. Tiles are well laid if:

The difference between the lower surfaces of the plates does not exceed 2 mm.
The height difference between the upper surfaces of the plates does not exceed 4 mm.
The height difference within the site should not exceed 10 mm.

As the installation of floor slabs demonstrates, after laying the slabs, they must be connected to each other and to the walls using metal connecting parts. Work on the connection of embedded and connecting parts is carried out by welding.

Do not forget that safety precautions must be observed. It is not allowed to work with a crane in an open area with a wind of 15 m / s, as well as in ice, thunderstorms and fog. During the movement of the slab with a crane, the assembly team must be away from the path along which the slab will be moved, from the side opposite to the feed. Despite the fact that using the services of a professional foreman and a team of installers significantly increase the cost of installing floor slabs, this is not the case when you can save. The foreman must provide a project.

Before ordering plates from the factory, it is necessary to carry out preparatory work. It is better to coordinate the delivery time of the machine with plates and the crane at the same time so as not to overpay for simple special equipment. In this case, the installation of plates can be performed without unloading, directly from the vehicle.

Preparatory work before laying floor slabs

First - Smooth surface support. The horizon should be almost perfect, a height difference of 4 - 5 cm is unacceptable. First of all, we check the surface of the walls, then, if necessary, level it with a concrete mortar. Subsequent work can be done only after the concrete has gained maximum strength.

Second - ensure the strength of the support zone. If the walls are built of brick, concrete or concrete blocks, then no additional measures need to be taken. If the walls are built from foam blocks or gas blocks, then before laying the plates, it is necessary to fill in the armored belt. Proper styling floor slabs implies that the bearing surface must be strong enough to support the weight of the slab and not deform along the abutment line. Neither aerated concrete nor foam concrete have the necessary strength. Therefore, a formwork is installed around the entire perimeter of the building, a reinforcing cage made of a rod of 8–12 mm is inserted into it, and then everything is poured with concrete with a layer of 15–20 mm. Further work can be continued only after the concrete has dried.

Third - install mounting towers. Telescopic supports, as described in the section on the installation of a monolithic floor slab, are installed in increments of 1.5 m. They are designed to take on the weight of the slab if it suddenly slips from its place. After installation, these towers are removed.

Installation of hollow core slabs with a crane

After the freshly poured concrete has taken on sufficient strength and dried, the installation of floor slabs can begin directly. For this, a crane is used, the lifting capacity of which depends on the size and weight of the slab, cranes of 3-7 tons are most often useful.

Stages of work:

A concrete solution is applied to the bearing surface with a layer of 2 - 3 cm. 150 mm. If the slab rests on two opposite walls, then the mortar is applied to only two walls. If the slab rests on three walls, then on the surface of three walls. Directly laying the plates can begin when the solution gains 50% of its strength.

While the mortar dries, the crane operator can hook the slings onto the slab fasteners.
When the signal is given to the crane operator that it is possible to feed the slab, the team of workers must move away from the place where the slab is moving. When the slab is already very close, the workers hook it with hooks and unfold it, while damping the oscillatory movements.

The stove is directed to the right place, one person should stand on one wall, and the other on the opposite. The slab is laid so that its edges rest on the wall at least 120 mm, preferably 150 mm. After installation, the plate will squeeze out the excess solution and evenly distribute the load.

If there is a need to move the plate, you can use a crowbar. It is possible to align its location only along the laying zone, it is impossible to move the plate across the walls, otherwise the walls may collapse. Then the slings are removed, and a signal is given to the crane operator to pick them up.
The procedure is repeated for all plates without exception. The rules for installing floor slabs suggest that the alignment of the slabs should be carried out along the bottom edge, since it is the bottom surface that will be the ceiling in the room. Therefore, the slab is laid with the wider side down, and the narrower side up.

You may come across a recommendation that it is necessary to lay reinforcement in the support area of \u200b\u200bthe slab. Proponents of this method say that it is more convenient and easier to move the stove. In fact, it is forbidden to put anything other than concrete mortar under the slab. technical card. Otherwise, the slab can easily move out of the support zone, as it will slide over the reinforcement. In addition, the load will be distributed unevenly.

Laying floor slabs on the foundation is practically no different from laying floors. The technology is exactly the same. Only the foundation surface must be carefully waterproofed before laying the slabs. If the project provides for non-standard support of floor slabs, then special steel elements. Such work should not be done without a specialist.

Anchoring - tying plates together - can be done in two ways, depending on the project.

The first - tying slabs with reinforcement. Reinforcing bars with a diameter of 12 mm are welded to the fastening embedded elements on the slab. At plates from different manufacturers the location of these elements can be different: in the longitudinal end of the plate or on its surface. The most durable connection is considered to be diagonal, when the plates are connected to each other with an offset.

Also, the plate must be connected to the wall. Why is reinforcement embedded in the wall.

The second way - ring anchor. In fact, it looks like an armored belt. A formwork is arranged along the perimeter of the slab, reinforcement is installed in it and concrete is poured. This method slightly increases the cost of laying floor slabs. But it's worth it - the plates are clamped from all sides.

After anchoring, you can start sealing the cracks. The gaps between the floor slabs are called rusts. They are filled with concrete grade M150. If the gaps are large, then a board is tied from below, which serves as a formwork. If the gaps are small, then the floor slab will be able to withstand the maximum load the very next day. Otherwise, you must wait a week.

All modern slabs with round voids are produced with the ends already filled. If you purchased plates with open holes, then they must be filled with something 25 - 30 cm deep. Otherwise, the plate will freeze. You can fill in the voids mineral wool, concrete plugs or simply fill with concrete mortar. A similar procedure must be performed not only on those ends that face the street, but also on those that rely on internal walls.

The price for laying floor slabs depends on the amount of work, the area of \u200b\u200bthe house and the cost of materials. For example, the cost of only PC floor slabs is approximately 27 - 30 USD. per m2. The rest - related materials, crane rental and hiring workers, as well as the cost of shipping plates. Professional teams for the installation of floor slabs have a variety of prices from 10 to 25 USD. per m2, maybe more depending on the region. As a result, the cost will be the same as for pouring a monolithic floor slab.

Laying floor slabs: video example

Filling a monolithic floor slab is not the easiest, but a truly universal and time-tested method.

In this article, we will cover the main structural features and stages of flooring, as well as types of formwork, including fixed formwork.

Building typology and scope

The main scope of monolithic ceilings are buildings with load-bearing brick walls, block masonry or concrete panels, as well as domed houses. The requirements for the solidity of the overlap may be due to:

non-standard building plan;
the need to significantly increase the bearing capacity of the floor;
increased requirements for hydro and noise insulation;
the need to provide free planning;
reducing the cost of interior decoration.

Filling is carried out, as a rule, after the completion of the construction of the walls of the first floor. However, there are options for pouring monolithic ceilings already in buildings with a roof, if weather or other conditions so require. In this case, I-beams are mounted on the masonry of the lower floor and a crown is poured along the perimeter of the bearing walls to the height of the ceiling. Also, to strengthen mechanical bonds, with inside the crown is released by 40–50 cm of embedded reinforcement. Its total cross section cannot be less than 0.4% of the cross section of the longitudinal section of the crown.

Design calculations of the supporting structure

When choosing the span length, it should be related to the thickness of the slab as 30:1. However, when independent design there is practically no point in making a floor thicker than 400 mm, since the bearing capacity of the structure increases along with its own weight and static stresses. Therefore, the permissible load on makeshift floors rarely exceeds 1500–2000 kg / m 2.

The situation can be remedied by including in load-bearing structure I-beams steel beams laid on a concrete-leveled masonry surface of load-bearing walls. Another way to increase the length of the span while maintaining relative freedom of layout is to support the ceiling on columns. With a thickness of a monolithic structure up to 400 mm and a span in four directions from columns up to 12 meters, the cross-sectional area of \u200b\u200bthe support is 1–1.35 m 2, provided that the cross section of the embedded reinforcement in the column is at least 1.4%.

Calculation of reinforcement of a monolithic slab

In general, the thickness of the plate is determined by the amount of reinforcing steel that is embedded in it. Reinforcement density, in turn, depends on the limit permissible load and fracture resistance. Avoiding special cases, one can give general example design that demonstrates full compliance regulatory requirements with a sufficiently high margin of safety.

In private construction, reinforced concrete is reinforced with reinforcement with a periodic profile of class A400, aka A-III.

Diameter of rods in slabs thick:

up to 150 mm - not less than 10–12 mm;
from 150 to 250 mm - not less than 12–14 mm;
from 250 to 400 mm - not less than 14–16 mm.

The reinforcement is laid in two meshes with a mesh size of 120–160 mm, the thickness of the concrete protective layer from the edges of the slab is at least 80–120 mm, and at least 40 mm above and below. The direction of laying four rows of reinforcement, starting from the bottom: along, across, across, along. For ligation, galvanized wire with a thickness of at least 2 mm is used.

Installation of formwork of various types

The formwork must withstand a load of 500–1100 kg/m2, including the dynamic impact of falling concrete. To create a formwork plane, you can use:

Plastic sheets of reusable formwork.
Moisture resistant plywood 17–23 mm thick.
OSB 20–26 mm thick.

The edges of the slabs should fit snugly against the walls; it is not allowed to use formwork with gaps at the joints of more than 2 mm, unless it is planned to cover the surface with a waterproofing film.

Sometimes it is reasonable to make the formwork permanent, using profiled sheets for this, orienting them narrow shelf way down. They are placed along the slab so that the waves form numerous stiffeners during pouring. The calculation of the thickness is carried out from the lower edge, thus saving the concrete mixture is 20-25%. In this case, the height of the ridge should not exceed a third total thickness plates. If the formwork is not planned to be removed, self-tapping screws with a rubber washer are screwed into it and tied with a thin wire to the reinforcement.

Formwork installation begins with the placement of racks: these can be either steel telescopic racks with a tripod and a unifork, or wood without defects with a cross section of at least 100 cm 2. Each post must be connected to two adjacent slanted braces from inch board. Racks are mounted along the lines of the beams, the distance between which, depending on the thickness of the plate 150–400 mm, is:

190–240 cm with plywood thickness up to 20 mm;
210–260 cm with plywood thickness from 21 cm.

In this case, the distance between the uprights of one beam, depending on the gap between them, is:

from 140 to 200 cm with a span of up to 150 cm;
from 120 to 180 cm with a span of 160–210 cm;
from 100 to 140 cm with a span of 210–250 cm.

The main beams, as a rule, are made of timber 100x100 mm. Secondary beams are laid across them with a step of 500–650 cm, which have a cross section of 50% of the main ones. If the formwork is made of profiled sheet, the step of the secondary beams is equal to 3.5 distances between the waves.

Vertical formwork is mounted from retaining panels attached to the outer wall of the building. Often, aerated concrete blocks 80–100 mm thick are laid around the perimeter to hide the floor belt.

Reinforcement and strapping

After the formwork is installed, it is lubricated with an anti-adhesive compound and the laying of the reinforcement begins. On the crowns and supporting ribs, the rods are tied into a square, keeping the minimum allowable protective layer. The main array of overlap is reinforced with mesh. The bottom layer is laid on plastic "crackers" that control the preservation of the lower protective layer. The mesh is tied up at the intersection of every third rod.

After tying the lower mesh, intermediate clamps are installed on it every 100 cm in a checkerboard pattern. To strengthen the support on the walls, end clamps are mounted. These elements help maintain the design distance between two reinforcement planes.

The mounted upper mesh is connected to the lower connecting brackets. After completion of the installation, the reinforcing structure should be as one piece and easily take the load from people walking on it.

Pouring concrete

Monolithic floors are poured with concrete grade B20-B30, prepared in factory conditions. Filling monolithic ceilings should be carried out in one stage, so filling the space with small doses is not recommended. If it is impossible to perform the entire amount of work at once, sections of the slab must be cut with a mesh with a cell of 8–10 mm.

The supply of the mixture to the ceiling can be carried out by a concrete pump or a bulk bucket lifted by a crane. After feeding to the top, the mixture is evenly distributed, seated by vibration and left to harden.

Further actions

Concrete gains sufficient strength after 4 weeks, all this time it needs periodic wetting and protection from rain for the first 2 days. After drying, the formwork can be removed and the walls can be erected.

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. AT modern technologies most often use a plate reinforced with reinforcement.

Description of types, design features, technical requirements

Depending on location and functional purpose concrete floors are of 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 right 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;
wall thickness under concrete blocks 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 for 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. On reinforced belt apply thick enough 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 designs 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 set composition is covered cement-sand mortar medium density, align the 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 start next step construction.

Along with wooden floors and reinforced concrete slabs, monolithic ones are also popular among private developers. Their advantages include not only the solidity and durability inherent in the same plates, but also the ability to cover rooms of any configuration. At the same time, the disadvantages include a large mass of plates, requiring a reinforced base and wall materials increased strength, and the need to assemble the formwork. Therefore, many self-builders, including the craftsmen of our portal, prefer a lightweight variety - monolithic ceilings on a profiled sheet, which will be discussed in the material. Consider:

What is a monolithic overlap on a profiled sheet.
Technology of the device of steel-reinforced concrete floors.
The experience of the portal participants in the installation of unsupported monolithic ceilings according to the profiled sheet.

Monolithic overlap on a profiled sheet

Initially, NIIZhB (Research Institute of Concrete and Reinforced Concrete) of the USSR State Construction Committee developed a method for pouring monolithic reinforced concrete floors with steel (SPN) for industrial buildings and structures. The first recommendations for the design of monolithic reinforced concrete floors with SPN were developed in 1987, after almost two decades STO 0047-2005 appeared, in fact, a slightly updated version of the first version. However, for those who want to understand the technology and make calculations on their own, without resorting to the services of a pro, our old-timers are advised to first study the training manual from the Land of the Soviets.

Yury

If you want to deal with extra costs, read the recommendations for the design of monolithic reinforced concrete floors with steel profiled decking, NIIZhB, 1987.

The essence of the technique lies in the fact that the corrugated board serves both as an external reinforcement of the plate, as well as the finishing layer.

When talking about industrial premises, such exterior finish more than enough. According to the developers of the service station, lightweight ceilings along the profile, compared to a conventional monolithic slab, have a number of advantages:

Reducing the amount of steel on beams - by 15%.
Reducing labor costs - by 25-40%.
Reducing the mass of the plate - by 30-50%.
Increasing the rigidity of floors (to horizontal loads).
Simplification of communications wiring - placement of highways in corrugations.
The absence of wooden formwork - an increase in the speed of work.

The use of steel-reinforced concrete floors in the construction of industrial and private buildings is permissible under the following basic conditions:

slightly aggressive and non-aggressive operating environment;
humidity regime up to 75%;
the temperature in the room is not higher than + 30⁰С;
used concrete without potassium chloride and other chlorine-containing additives.

That is, the main contraindication to this type of overlap is high humidity, which is why they are usually used as interfloor and are not used between the basement and the first floor or the basement and the first floor.

al185 FORUMHOUSE Super Moderator

The profiled sheet in the base will rot, who are interested in the timing, look with a search. On the protection of the wheel arches, galvanized self-tapping screws rust in a couple of months.

For pouring slabs, it is allowed to use both heavy and light concretes, but the compressive strength class for heavy concrete on fine-grained aggregates is from B15 (M200), for lightweight concrete on porous filler - from B12.5 (M150). The minimum layer of concrete above the profile flooring is 30 mm, if a finishing screed is provided, if without a screed - from 50 mm. The flooring is made of load-bearing profiled sheets (H), with a corrugation height of 44 mm.

Reinforcing bars of a periodic profile are used for the reinforcing cage, class A-III, and wire class Vr. If an overlap with a stairway is planned, then it is necessary to reinforce the reinforcing cage around the perimeter and install side formwork. Steel beams of the load-bearing frame are either rolled or composite profiles.

Technology for the installation of steel-reinforced concrete floors

In the original version, the profiled sheet is laid not only on the walls, but also on the frame of steel beams (girders), which is the carrier. The number and parameters of the beams are calculated individually, based on the dimensions of the overlapped span and the expected loads, the average step is from 1.5 to 3 m, but each sheet should have three support points - in the center and along the edges. Single-layer reinforcement - mesh, wire diameter from 3 mm, pitch 200 × 200 mm, thickness of the protective layer over the mesh is at least 15 mm.

Profiled sheets are laid across long side span, with wide corrugations down, along the length on overlapping runs, at least one wave, butt-to-width. Between themselves, the waves are fixed with rivets or self-tapping screws with a step of no more than 500 mm. In order for the profile and runs to work as one system, the flooring is fixed with rod anchors that are welded to the beams. Next to the load-bearing walls, the anchor must pass through each wave, on intermediate beams through one. In addition, the flooring is fixed to the beams by means of self-tapping screws or dowels.

However, the use of steel beams is not the most attractive option for self-builders, so many of the craftsmen of our portal prefer Alternative option- unsupported monolithic overlap along the profile sheet.

The experience of the portal participants in the installation of unsupported monolithic ceilings according to the profiled sheet

winder

Overlapping along a profiled sheet can be without I-beams or channels.

Instead of a frame, a bearing profiled sheet is used with a wave height of 60 mm or more, a thickness of 0.7 mm, and reinforced reinforcement - lower, upper, transverse and mesh. In this case, the profiled sheet is a non-removable formwork, and the reinforced reinforcing cage takes the main loads. The sheets are laid with a narrow corrugation down and, just as in the method with beams, they are oriented in waves across the long side of the span. It turns out a kind of ribbed monolithic overlap, only the ribs are formed not by removable formwork, but by corrugations. Unlike a steel-reinforced concrete slab supported by beams, this slab is not recommended to be poured with lightweight concrete, and the compressive strength class should be increased to B22.5 (M300).

winder

It is reinforced concrete that holds the load, neither foam concrete nor expanded clay concrete have the necessary strength. Strengthening the reinforcement in this case is useless.

When pouring, be sure to carefully vibrate the solution. If necessary, props are placed from below, which are removed after the concrete has gained strength.

One of our craftsmen decided to use the profiled sheet not only as a formwork, but also as an additional power frame.

worodew

I make a monolithic ceiling according to the H75 profiled sheet, 0.7 mm thick. To not lose it bearing capacity, after pouring, I decided to include it in joint work with concrete. I did this: with a puncher (drill 6 mm) in each ridge I punched holes every meter and inserted pieces of wire 6 mm thick, 10 mm long into them, and instead of stars I put and tied reinforcement on it, plus a mesh on top. Even stiffness has increased, I compare before and after knitting reinforcement.

Spans of 3.6 and 2.0 m, in a wave reinforcement 12 mm, on top - a wire mesh 5 mm thick, with a cell of 100 × 100 mm. From below, the waves were closed with gas block trimmings and sealed the cracks mounting foam, one bottle was enough for 70 m². The flooring rests only on external walls and on bearing wall in the middle. The slab was poured with a concrete pump, the ceiling thickness was 130 mm, the area was 76 m², about 7 m³ of mortar (M300) was taken. After a few hours, it was possible to cut off the bumps, focusing on the rule, the next day I moistened the slab and polished it.

The underfloor heating system is usually installed in finishing screed, but if desired, you can combine a warm floor and a monolithic ceiling on a profiled sheet.

Toha71

Is it possible to install TP pipes directly into the poured slab? Will the presence of TP pipes in it not weaken such an overlap? And if possible, how much thickness to add under the 20 pipe? I understand that the TP must be placed between the layers of reinforcement in order to upper layer reinforcement in concrete cannot be "drowned" for its normal operation? I would like to try once and pour the concrete evenly so that only the finishing self-leveling floor remains and you do not have to load the slab with an additional screed.

The method has the right to life, subject to an increase in the thickness of the overlap and the presence of certain experience.