Monolithic overlap with your own hands. How to make a monolithic concrete floor Concrete floors

09.11.2019

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 the laying of factory-made floor slabs. Such slabs are ordered at reinforced concrete factories, and then mounted with a crane and a team of workers. In those cases where the use of a crane on a construction site is difficult, or when the house has a non-standard layout and it is difficult to lay out finished slabs, a monolithic floor slab is 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 of 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.

Installation technology of monolithic floor slabs

Like everything related to construction, a monolithic ceiling begins with a project. It is advisable to order a calculation monolithic slab ceilings in the design office and do not save on this. It usually includes the calculation cross section plates on the action of the bending moment at maximum load. As a result, you will receive the optimal dimensions for the floor slab specifically in your house, instructions on which reinforcement to use and what class 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.

Installation of formwork for 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. 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 with a 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 bar that will hold the formwork, I-beam, 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.
Vertical formwork elements are installed. 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 racks 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 a wooden log or beam. Renting such racks will cost about 2.5 - 3 USD. per 1 m2 of area.

Reinforcement of a monolithic floor slab

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 meshes. 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. The vertical size of the latch is 120 mm. The installation step of the vertical clamps is 1 m, the rows should be staggered.

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 is 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 a 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.
Tiles are only laid on bearing walls, all piers are equipped only after the installation of floors.
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 plates should be placed as close to each other as possible, 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 is the laying of slabs with uniform gaps, which are then sealed with 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.

Scheme of laying floor slabs

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 - flat support surface. 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.

Mounting hollow core slabs ceiling 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.

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, putting anything other than concrete mortar under the slab is prohibited by the 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 are used for this. Such work should not be done without a specialist.

Anchoring floor slabs

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

First - tying slabs with reinforcement. Reinforcing bars with a diameter of 12 mm are welded to the fastening embedded elements on the slab. For plates from different manufacturers, the location of these elements may 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 is 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.

Sealing joints between floor slabs

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.

Filling voids at the ends of floor slabs

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 is 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.

Do-it-yourself monolithic ceiling, Construction Portal

Construction of houses In houses made of brick, concrete or concrete blocks, floors are usually made of reinforced concrete. They provide exceptional strength and earthquake resistance of the structure, and

Thank you.
Concrete was ordered M300. Supplier - titanbeton. en
Two drivers who visited me do not understand Russian, do not have maps, do not know the area. The first one had to be fished out in a neighboring town, according to his unintelligible tips, something like "I'm standing at the store, I don't remember what I was passing through." Basically, it got on my nerves. They carry 5 m3. Well, if there really was 4.5 m3.
Separately, a few words about the concrete pump. Initial price - 18 tr. Arrow 32m, poured through the fence without any problems without leaving the asphalt. The driver is a good man, although at the end he asked for 2tr more than what was allegedly claimed for the "move", but he explained and told everything about the filling process itself. The unit itself is very difficult to work with. Although the driver tried to supply concrete intermittently with one “pumping” of the pump, the pressure and flow rate required great efforts to turn the sleeve back and forth, directing everything inside such a narrow formwork, evenly distributing concrete in layers of 30 cm.
In total, 17 cubic meters of concrete were ordered, the possible refusal of the last mixer at RBU was agreed in advance, payment was made on the spot. After pouring 2.5 mixers, that is, 3/4 of the total volume, after thinking and thinking, we decided to hang up on the concrete unit, we were afraid that the formwork would not survive. They began to vibrate in the old fashioned way, with reinforcement bars - for the same reason. As it turned out, not in vain.
The concrete ran out, the last mixer left. In the receiver of the concrete pump, as expected, there are 200-250 liters of concrete left. The carrier said to point the sleeve somewhere in order to swing something else. Throwing your sleeve on thin wall partitions, we did not expect that in a couple of seconds he would spit out another 70-90 liters there almost to the top. And then the formwork cracked ... everyone froze. On M10 studs of medium height, washers with a diameter of 30 mm were pressed 0.5-1 cm on each side into wooden racks and as it turned out, one of the studs broke the nut. Thus, the formwork has become wider by these centimeter and a half. There was no further destruction, I exhaled. Geometry violations are not critical. After removing the formwork, they are not noticeable at all.
The remaining concrete was poured onto the platform next to the gate onto the bedding film. We also dragged this concrete into the formwork in buckets, leveling the level more or less everywhere, just up to the windows. Having done everything once more, they parted on this.
The next couple of days, periodically pouring concrete, on the ground closer to the pit, a formwork was assembled that could accept a 5-cube mixer. According to estimates, a volume of 4.8-4.9 m3 was needed. Having agreed with four working crests nearby, I made an order in TitanBeton. I made several portable ladders around the formwork, through which concrete could be poured immediately from the wheelbarrow. The mixer arrived and unloaded. We started to carry. Two people are constantly raking concrete with shovels, one carries it on a wheelbarrow, two more stand inside and pass buckets to each other. I don't remember exactly how long it took. But the concrete did not have time to rise. 2.5-3 hours, I think we managed. However, the concrete was not enough and well. All vibrated. I drove to the market for cement, leaving myself one assistant, they made about 9 more batches of 400 liters. I ran great. Covered everything with a film, left.
After waiting a few days, I began to slowly disassemble everything. I dismantled the trough for concrete, scaffolding, tore off the film. The weather was rainy, so I was not afraid for the concrete to dry out.

H The stronger the floor structure, the more reliable the protection. Concrete slabs are especially good for this. But in order to lay them, a crane is required, which is both expensive and not always possible to use.

An alternative for the floor device would be the use of monolithic concrete. Its laying can be done in relatively small portions, the weight of which allows manual work.

But how to ensure that a self-made monolithic concrete floor has sufficient strength and does not crack or, worse, does not collapse? Is it possible and how to do it without using complex calculations and formulas? Yes, it's possible. But let's go in order...

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How is the concrete floor

To begin with, let's figure out how a concrete floor slab works and how it works. Without this, some points may be incomprehensible.

The strength of concrete, like other stone materials, is not the same depending on the direction of the load. Best of all, it withstands compression, and worst of all, it withstands stretching.

Moreover, the difference is so great that in the calculations of the strength of structures, the tensile strength of concrete is usually not taken into account at all!

But the floor slab rests on the edges, and is loaded over the entire surface. At least its own weight. Obviously, she will tend to bend. If we consider the cross section of such a plate, then in the upper part it is compressed, and in the lower part it is stretched. Moreover, the efforts will be maximum at the top and bottom, and in the middle of the section they will turn out to be zero (see Fig. 1).

Since, as we have already said, concrete is disgustingly resistant to stretching, it is reinforced with metal reinforcement. Without her conventional stove would break even under its own weight.

Reinforcement is needed not only at the bottom of the section. There are other places in the floor slab that experience tension, they also need to be reinforced. How and what stresses arise can be seen in Figure 1.

Interesting: The Parisian gardener Joseph Monier, who invented reinforcement, thus becoming the "father" of reinforced concrete, was nevertheless a complete ignoramus in construction. So, until the end of his days, he was sure that the reinforcement should be laid in center sections of bent structures. In fact, here it is absolutely useless.

We select reinforcement and brand of concrete

The greater the thickness of the slab and the strength of the concrete, the greater the diameter of the reinforcement, the stronger the overlap. But at the same time heavier and more expensive.

For the solid part, we use OSB3 with a thickness of 16 mm. It is cheaper than the waterproof plywood commonly used on a construction site, and then goes for, on, subfloors, etc.

We will find out the layout of beams and racks when using inventory formwork when we rent it. This scheme depends on both the load and the type of equipment.

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 those cases where the use of a crane on a construction site is difficult, or when the house has a non-standard layout and it is difficult to lay out finished slabs, a monolithic floor slab is 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

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 receive the optimal dimensions for the floor slab specifically in your house, instructions on which reinforcement to use and what class 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 option when an ordinary country house is being built 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. First - rental of ready-made removable formwork from metal or plastic. Second - making formwork on site using wooden boards 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.

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.
Vertical formwork elements are installed. 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.

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. Considering 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 - supports as in the photo. The upper and lower shelves of the latch are 350 mm. The vertical size of the latch is 120 mm. The installation step of the vertical clamps is 1 m, the rows should be staggered.

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.

pouring concrete

How to properly lay floor slabs

Rules for laying floor slabs

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 of 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 is the laying of slabs with uniform gaps, which are then sealed with 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 at the construction site, as well as to comply with the entire technological process and the rules described in SNiPs, the foreman at the construction site must have a flow chart for the installation of floor slabs. 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.

Preparatory work before laying floor slabs

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 laying of 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.

Installation of hollow core slabs with a crane

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.

Laying floor slabs on the foundation is practically no different from laying interfloor 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 are used for this. Such work should not be done without a specialist.

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

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.

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 the voids with 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.

Laying floor slabs: video example

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 can be no more than 900 cm. This is the maximum allowable length 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;
slabs can only be laid on load-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, after securing the formwork under the ceilings so that the mortar does 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 of formwork, use edged board not less than 2.5-3.5 cm thick. You can use moisture resistant plywood from 2 cm thick.

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;
timber;
a hammer;
hacksaw;
level;
nails;
axe.

Formwork installation

First step. Install the vertical supports. The best way– adjustable telescopic metal poles. In their absence, wooden logs with a diameter of 80 mm or more are also suitable.

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 transverse wooden beams on the longitudinal bars, 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!

How is the concrete floor

We select reinforcement and brand of concrete

Do-it-yourself monolithic floor slab

pouring concrete

How to properly lay floor slabs

Rules for laying floor slabs

Floor slab laying technology

Preparatory work before laying floor slabs

Installation of hollow core slabs with a crane

Laying floor slabs: video example

Formwork installation

Formwork set

Formwork installation

Video - Installation of slab formwork

Reinforcement order

concrete preparation

Slab pouring

spilling

Finishing fill

Concrete care after pouring

Video - Do-it-yourself monolithic overlap