Lightweight monolithic overlap on a profiled sheet - constructive, the experience of the portal participants. We reinforce and fill a monolithic floor slab How to make a monolithic floor between slabs

During the construction of buildings of two or more floors, an integral part of the work carried out is the installation of floor slabs. Most often, of course, factory-made floor slabs are used, which, after pouring the armored belt, rest on it. However, in some cases, preference still has to be given to doing all the work with your own hands.

There are cases when it is impossible to use ready-made factory plates. For example, if the building has a non-standard size or shape, and cutting floor slabs will not help to completely cover the entire required area. Then the only option will be filling with your own hands.

If, due to the limited size of the construction site or difficulties in driving up to it, the use of a crane is unrealistic - then you can also pour the floor slab with your own hands.

The advantage of doing it yourself

Although the implementation of such work is a laborious process, nevertheless, it has a number of advantages, due to which, even with the ability to use factory plates. Some still prefer to make a floor slab with their own hands.

The advantages of making your own hands:

• Monolithic floor structure, no seams, joints. Due to this, the load is evenly distributed over the entire slab, the walls of the building, as well as the foundation.
• The possibility of non-standard layout of the house. Pouring the slabs on your own allows you not to adjust the dimensions of the house and the layout to the dimensions of the factory products.
• No need for heavy equipment.
• The ability to significantly reduce costs by doing most of the work yourself.
• There is no need to fill the armored belt, in the case of using factory reinforced concrete, you need a belt under the floor slabs.

Formwork installation

There are two options for the construction of horizontal formwork: renting plastic or metal formwork, as well as performing work on mounting the formwork under the slab on your own.

Work begins with the installation of vertical racks, on which the entire structure and a monolithic floor slab will rest. Such racks can be rented or bought second-hand. They are good because their height can be adjusted and they can be used for any ceiling height. The distance between the posts should be about a meter. It is necessary to place a longitudinal beam on the racks, which will support the entire structure.

The next step is to install the frame. To do this, it is necessary to use a beam with a section of 15 * 5 cm. The frame is constructed along the perimeter of the building, and to ensure greater reliability, transverse bars are additionally placed. Each next cross beam is mounted at a distance of about 70 cm from the previous one.

Preparing the surface for pouring

After the construction of the frame, it is necessary to prepare the surface for pouring. To do this, boards or plywood are laid on the frame (the first option is cheaper, but thanks to the second one, you can achieve a flat surface of the lower floor ceiling). These boards should be closely adjacent to the wall so that there are no gaps. After that, it is necessary to level the surface with the help of support posts so that the top of the formwork exactly matches the edge of the brick or foam block wall.

Next, the vertical part of the formwork is mounted. At the same time, it must be remembered that the slab must go a certain distance onto the expelled wall. In order for the formwork boards to be used for other purposes after removal, it is better to cover them with plastic wrap.

We apply reinforcement

If factory products are used for overlapping, then the arrangement of an armored belt is mandatory for buildings made of blocks. The reason for this is the fact that under the weight of the slabs, due to uneven shrinkage of the building, serious cracks in the walls can occur in the future. The reinforced belt in this case will ensure that the entire mass of the plates will be evenly distributed on the walls of the building. The device of the armored belt is similar to a strip foundation, which is supported by the walls of the building.

However, if the floor slab is poured, the resulting monolith will evenly distribute the load on the walls and protect against cracking. Therefore, the need to build an armored belt when doing work with your own hands disappears.

How to reinforce monolithic floors? For this, it is necessary to use steel reinforcement with a diameter of 10-14 mm. For reliability, concrete is reinforced with two meshes: one is located at the bottom of the platform to be poured, the other is at the top. The reinforcing cage should be with a cell width of either 15 or 20 cm. For small buildings, a grid with a cell of 20 * 20 cm will be enough.

If the length of the reinforcement bars is not enough to completely cover the entire overlap distance, then the bars should be overlapped by 40 cm. It is also desirable that each next row has a reinforcement joint at the other end of the ceiling. After laying all the reinforcement, it must be tied with a knitting wire.

The mesh should go on the walls of the building by at least 15 cm (if the walls are brick) or 25 cm (for the walls of aerated concrete). Since there is no armored belt provided when pouring the slab on its own, it is very important that the reinforcement enters the walls. The lower mesh must be raised 2-2.5 cm above the lower level of overlap. The upper grid is located at the same distance from the top of the platform being poured.

During the preparation of the site for pouring concrete, it is important not to forget about the cavities for laying wiring and communications.

Upon completion of work with the reinforcement of the slab, concreting of the floor follows.

pouring concrete

For concreting the slab, it is best to use concrete ordered from the factory. This will help save time and effort, as well as ensure the uniformity of the partition and increase the strength indicators. If the overlap is poured quickly and evenly enough, and this is achieved with the help of a concrete pump, the solution does not begin to solidify early and thanks to this, the overlap can rightly be called monolithic.

Also, a deep vibrator must be used to compact concrete. It must be applied until the concrete stops settling and the release of air bubbles stops.

In order to completely fill all the gaps before filling the ceiling with concrete, pour the spill first. It is performed in a thin and slightly liquid layer. When this layer is compacted and evenly distributed, you can start pouring the main layer.

Features at work

Some advise not to fill to the edge of a centimeter 2, and then after a few days, when the concrete grabs, fill the remaining space with a liquid solution with the help of beacons. This will achieve evenness and smoothness of the interfloor overlap. Self-levelling floors can also be used for this purpose.

If the do-it-yourself floor slab is made in winter, then the concrete must contain antifreeze additives. However, it is worth remembering that they affect the time of gaining strength of concrete. Therefore, the warmest time of the year is definitely the best time for self-pouring the floor slab.

The process of curing concrete

After the ceiling is filled with concrete, it cannot be said that all work is completed and you can just wait for the slab to gain its strength. The process of solidification of the solution is inextricably linked with the evaporation of moisture, and this leads to the appearance of cracks in the concrete. In view of this, for the first time after pouring, you need to regularly water it. It is best to use a hose with water in this case, because raising bucket after bucket to the height of the second floor is a thankless task.

If the concrete dries in hot weather, watering will not be enough, you need to cover the slab with polyethylene.

After the concrete has hardened, the entire formwork must be removed. To ensure that this process is not so difficult, care should be taken at the stage of installation of the structure. If all the boards have been covered with polyethylene, they can be used in the future.

As you can see, if desired, floor slabs can be made by hand. And although this process is laborious and lengthy, the resulting strength of the plate is worth the effort.

Overlapping is one of the most important load-bearing elements of the house. It is on him and on the foundation that all the main load of the house (people, furniture, equipment) falls, which is transferred to other building elements - beams, walls and crossbars.

It is extremely important that all the stress forces in the building are correctly distributed, because its durability, reliability and safety for people to live depend on this. So, one of the most time-tested designs is a monolithic ceiling in its classic, lightweight and modified form. To understand the manufacturing technology of all its three options, we have prepared detailed master classes and video tutorials for you!

In modern houses, special requirements are imposed on the ceiling. Surely you will not be surprised by the presence of a jacuzzi on the second floor, or the installation of heavy equipment. And therefore, ideally, the ceiling should be well insulated, soundproof, reliable and cost within reasonable limits.

The durability and reliability of the whole house will directly depend on how well this overlap is done. Unfortunately, to this day we hear about cases when the overlap does not withstand.

So, for example, not so long ago, the whole second floor with Indian students collapsed. And there is no more annoying situation when a new house is built, where a lot of money and effort have been invested, and cracks begin to go along the walls.

Today in Russia, wooden floors, reinforced concrete slabs and a monolithic slab are most often equipped. And monolithic overlap is considered one of the most reliable.

Even with an explosion of domestic gas, its safety margin is not exhausted immediately, and therefore it does not collapse in the first hours and allows you to quickly evacuate. And from the fire it will neither melt nor burn. And his device looks like this from the inside:

With the help of monolithic ceilings, it is especially convenient to cover rooms of any configuration. For example, you decide that the house has unusual corners, or a chic polygonal kitchen will act as a separate bay window. In this case, covering such a part of the house with a rectangular slab will not work. But bending the metal reinforcement of the desired shape and pouring it with concrete is easy.

This is an important point! Modern architects often say that the geometry of modern houses is far from a rectangle. Indeed, bay windows, ledges and artsy curvilinear sections cause a lot of problems when you need to think about reliable overlap. For example, it is quite difficult to pave something like this with ordinary slabs, they will have to be cut at least.

Not only does this make the work more labor-intensive, but it also requires the use of a crane that will lay such slabs. And for the crane, suitable access roads are already needed, which country buildings usually cannot boast of. Whereas a concrete mixer and a pump are enough to fill the ceiling of even a large area.

Among the shortcomings, we note the significant weight of such an overlap and the high consumption of concrete. Although in construction, as they say, they are not looking for ease.

Classic monolithic floor: step by step

Let's first consider the design and manufacture of a classic monolithic floor, and only then its newer types.

At the heart of this overlap - strong, tightly connected reinforcement, which serves as a kind of skeleton of the ceiling. Before you start pouring, you will need to tie the rods together.

Moreover, there are many ways and types of such knitting, and it can also be done manually or with the help of special equipment. If you have the time, desire and helpers, you can easily learn this skill.

And this video will help you figure out whether to knit rods or cook better, and how to do it right:

To make the correct reinforcement cage, you need an accurate calculation. Usually we are talking about two meshes in the upper and lower zones, with a diameter of 12-14 mm, from A400 class reinforcement. In this case, the pitch of the rods should be 20 cm in two directions.

Sometimes additional fittings are also installed. Both grids should be at a distance of 25-30 mm from the edge of the slab. Place clamps under the bottom one at a distance of 1 meter from each other, right at the intersection of the reinforcement.

And in order for the upper mesh to be at a certain distance, special stands made of rods with a diameter of 10 mm or more modern plastic devices are installed under it:

In this embodiment, sections of rods were welded to the reinforcement as supports:

You can put such supports more often, this will only be a plus:

And this type of support can be purchased at the store, it is called "chairs":

If you undertake to knit reinforcement, then use such tricks of home craftsmen who have got used to using improvised tools for this purpose. Here's a great way to quickly tie rebar with minimal effort.

Step 1. We take the wire, bend it at the ends to make “ears”, and bring it under the reinforcement:

Step 2 From above we connect the ends of the wire and make a loop for the hook. It takes 4-5 seconds on the strength:

Step 3 We insert the hook with one end into the screwdriver, and with the other - in a loop of wire. We turn on the tool for a second - and the armature is firmly connected. It remains only to dry the resulting tail.

It will not interfere with the concreting process, but it can scratch the legs of passing workers. Therefore, it is better to get rid of it immediately by bending it to the reinforcement rod:

Here, for example, is a great easy way to knit rebar for beginners:

Here is an example of how reinforcement is tied with ordinary metal wire:

And this method of fittings is already for professionals:

In this case, a single reinforcement was tied for the overlap device:

By the way, an armored belt is not needed for a monolithic ceiling. After all, such an overlap in itself perfectly redistributes the load from all sides. The only thing to do is to install the formwork over the entire area.

Let's take a closer look at the main stages of the devicemonolithic floor slab:

• Step 1. Installation of supports - metal racks with adjustable height. The optimal distance between them is 1 meter, and from the walls - 20 cm.
• Step 2. Crossbars are laid on the racks, which are suitable for an I-beam, channel or bar.
• Step 3. Formwork is organized on top of the crossbars, perfectly flat. To make it easy to remove later, use a waterproofing film for boards or engine oil for metal.
• Step 4. We make a reinforcing frame in the chosen way.
• Step 5 Now let's move on to concreting. Concrete should be poured using a concrete pump, and vibrated with a deep vibrator. After that, the concrete dries and gains strength. The first week, while it dries, moisten it with water, and after 28 days, remove the formwork.

Here is a step-by-step process for installing a monolithic slab:

The classic monolithic floor slab is often made insulated. In this case, the insulation additionally insulates the floor:

If there are underfloor heating pipes in the ceiling, then the concrete membrane on top of them should be from 8 to 10 cm. But keep in mind that every 1 cm of the upper concrete membrane reduces the useful load of the floor by as much as 25 kg / sq.m. Those. with every extra centimeter, the floor becomes heavier and the less it will be possible to load it with furniture and appliances in the future.

The total thickness of the structure in the end will be from 180 to 220 mm.Of course, compared to wood, such an overlap has much more weight. Therefore, its device is not possible for all designs.

For example, for a wooden or log house. Also, a monolithic ceiling is not made on spans of more than 7 meters, otherwise it turns out to be too heavy. If you have construction experience, then you know how heavy concrete is. See how much you need even for one square meter of slab:

In addition, the installation of a monolithic floor according to this scheme takes a lot of time: installation and dismantling of the formwork, the manufacture of reinforcement, the installation of a three-dimensional frame, pouring concrete and its solidification.

Also about The absence of the need for a special crane does not mean that you will not need equipment at all. The fact is that it is not difficult to raise beams weighing 60 kg to the height of the second floor with two or three people, but from 110 kg is already a problem.

Prefabricated monolithic ceiling: economy and practicality

As we have already said, monolithic floors, of course, are all good, except for the cost of concrete and their own weight. It is logical, because cement is used here immeasurably, the whole floor is poured! It is because of this, in order to find savings, a new type of flooring was developed - prefabricated-monolithic.

In comparison with the usual monolithic ceiling, the prefabricated-monolithic one turns out to be more economical by as much as 30%. Yes, such an overlapIt is more expensive than conventional slabs, but much less laborious and cheaper than monolithic.

We can say that this is such a subspecies of a monolithic floor, in which there are additional blocks. They are covered with reinforcement from above and poured with concrete in the form of a thin layer. What is the point? Blocks are much lighter than concrete, and fill the main space.

It turns out that there is already much less heavy cement here. And the savings, and the overlap itself is much lighter in weight. And this significantly affects the estimate of the foundation, which bears the main load from the weight of the house:

Let's take a step-by-step look at the technology of mounting a prefabricated monolithic floor.

Installation of beams and props

For prefabricated monolithic floors, special lightweight reinforced concrete beams are used, with reinforcement inside. It is placed freely, in the form of spatial frameworks. Thanks to this, the beams are so strong that they are made long enough, even with an overlap of 9 meters. This is an important point if you are planning for the hall of your house to be spacious.

Less commonly, special T-beams with a chamfered bottom are used. Just keep in mind that only prefabricated beams are used for the device of precast-monolithic overlapping. You can’t cook them in your garage - it’s dangerous! These beams are called trigons and have precisely calculated geometry and weight.

Today, manufacturers often offer lighter galvanized steel beams on a reinforcing cage. Such a beam weighs only 6 kg/m. For such a beam, lifting equipment is not needed, and at the same time it does not lose strength. But its weight will be influenced by rods of additional longitudinal temperature.

The diameter and number of beam rods are selected based on the calculation of the bearing capacity of the floor. What is the main advantage of a prefabricated monolithic floor - the ability to flexibly select the bearing capacity depending on the expected operational load.

A separate type of such overlap is Bonolit. These are steel beams with a recognizable triangular reinforcement cage. Aerated concrete blocks are located between the beams, which also serve as a fixed formwork. For the flooring device, heavy fine-grained concrete of class M250 (B20) is used.

To everything, the beams can be joined at the right angle in order to block the room even of a complex configuration and modify it right at the installation site. Also, a leveling screed is not required, which significantly reduces the consumption of concrete. The speed at which such a slab is assembled is also impressive: just four workers are enough to assemble the slab in just two work shifts, and they do not need to be highly skilled.

Additionally, the beams are supported with wooden supports or special telescopic racks. They are removed after the concrete has set.At the same time, telescopic racks outperform wooden props in many respects.

After all, they can still be moved up and down to achieve maximum accuracy in the location of the beams. Then when you have to use wedges and reinforcement with jibs with boards, which takes much more time.

They put racks at a distance of 1.5 meters from each other. It is important to provide the stop with a solid base, like well-compacted soil or a foundation slab, otherwise the stand runs the risk of pushing through, even on a wooden lining underneath.

Laying block inserts

Insert blocks are supported on reinforced concrete beams. They are held by two side grooves at the bottom. Moreover, a crane is not needed to install the blocks themselves, because their weight is relatively small - only 19 kg. The weight of the prefabricated monolithic floor is further reduced with the help of dense foam inserts located inside it.

This is often done in Europe, although it makes sense to worry about the fire safety of such an overlap. But liners made of aerated concrete have a much higher degree of fire resistance.

By the way, not only special T-shaped blocks, but also aerated concrete, expanded clay concrete, polystyrene concrete or ceramics can become a filler between metal beams. The standard height of the beams is 10, 15.20, 25 or 30 cm.

At the same time, the armored belt is poured simultaneously with the ceiling, where immediately, right at the construction stage, it is allowed to install pipes for a water-heated floor, and only then fill the floor.

The entire structure of blocks and beams serves as a fixed formwork, into which a layer of M200 concrete, pre-reinforced with a mesh with small cells, 100x100 mm, is then laid. For fittings there is a standard wire 5-6 mm in diameter.

Reinforcement and concrete pouring

Now they are equipping a concrete diaphragm - the upper 5-centimeter layer of concrete. This layer will be located above the blocks and inserts and will form the top surface of the floor. During the installation of the floor, it is important to ensure that debris such as leaves and branches does not fall on the reinforcement, formwork or concrete.

On top of the blocks with a certain gap, a reinforcing mesh or frame is knitted. To do this, they take the “eight” or “ten” reinforcement, and the cells are made 10x10 or 15x15 cm in size.Next, the freshly laid concrete is compacted with a bayonet or a vibrating screed.

There are different types of such ties. So, one of the highest quality is considered to be Founding Startoline. Due to the presence of light aggregates and reinforcing fibers inside the mixture, such a screed has excellent heat and sound insulation properties. Such a screed is especially good in the “warm floor” system. And, for example, Sika Level Pro allows you to make a self-leveling thin screed with a thickness of only 5 mm.

But it is important to correctly calculate the load on the foundation. One way to lighten the overlap is to make the screed thinner. After all, when installing a classic screed with a thickness of 50 mm, the load per 1 square meter is already 100-120 kg. After all, not always only concrete is able to level the floor. Therefore, in the floors, a polymer-modified cement-based dry mix is ​​​​used.

Here's what the installation of a prefabricated monolithic floor looks like in practice:

As a result, the prefabricated-monolithic floor has high rates of sound insulation and thermal conductivity. At the same time, the carrier is capable of being large enough to arrange not only fireplaces on the second floor, but also entire pools. It ranges from 200 to 1000 kg per square meter.

Another bonus of using a prefabricated monolithic floor is that it is suitable even in hard-to-reach places, of which there are many during the reconstruction of a building. Thanks to the internal blocks, such an overlap is easily made to the desired shape, cut or changed.

If we compare the load on the foundation, then with an equal thickness of 25 cm, a monolithic floor slab will weigh 500 kg / sq.m., and a prefabricated monolithic one - 300 kg / sq.m.So why is a prefabricated monolithic floor in practice as strong as a slab? The whole secret is in the increased height of the beam section and additional longitudinal reinforcement, which covers unsupported spans up to as much as 16 meters long!

But eh this type of monolithic overlap is not yet popular enough in Russia, and many believe that there is too much preparatory work and therefore the classic screed is preferable. For aerated concrete walls, this option is, of course, safer.

Lightweight overlap according to the profiled sheet: calculations and manufacturing

Another type of monolithic flooring is lightweight on corrugated board. It involves the use of profiled steel with a polymer and zinc coating as the basis. But not every professional sheet is suitable for this task.

As you know, corrugated board differs in profile, which has a different shape and height of the corrugation. The higher the corrugation, the higher the rigidity of the overlap. Despite the fact that such sheets are metal, they are reliably protected from corrosion. Even in the factory, they are coated with polymer paints and a special zinc layer.

Also pay attention to the brand of corrugated board. So, "C" means "wall", and "NS" - "universal". Only sheets of the “H” brand are suitable for the overlapping device, which means “bearing”.

By themselves, the corrugations of corrugated board act as something like a frame, and therefore there are not so many reinforcement rods here as with a classic monolithic slab. As beams, either I-beams or channels are taken.

If desired or necessary, you can insulate the ceiling, giving it heat-insulating properties and sound insulation:

High-quality, arranged according to all the rules, the overlap will last at least 100 years! Do you still have questions about the installation of a monolithic ceiling? Ask, we will be happy to answer them!

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 the sleeve on the thin wall of the partition, 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 by 0.5-1 cm were pressed into wooden racks on each side and, as it turned out, a nut was torn off on one of the studs. 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.

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

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.

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:

1. 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.
2. Installation of formwork type "deck".
3. Reinforcement of the slab with steel bars.
4. Pouring concrete.
5. 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 - 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.

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 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.

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.

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. 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 - 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.

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 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.
• 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.

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 should 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 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.

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, 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 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.

The 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 - 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 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.

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.

Laying floor slabs: video example

When building a house with their own hands, each person is faced with the need to make, which will be found on every floor from the basement to the attic.

There are three options for such overlaps, each of which has its own nuances:

• wood (round timber and timber);
• slabs (reinforced concrete and hollow);
• monolith (full-fledged and on metal beams).

The most difficult and expensive is considered to be a monolithic floor, because. it takes a lot of time (about a month), money and labor to make it. However, in the end, the design justifies itself 100%, because. it is the most durable, has the best insulating properties, and almost never even requires cosmetic repairs.

In order to make a monolithic ceiling, you should decide in advance which type you will like, because. they have significant differences in all respects.

Differences will include reinforcement, concrete (thickness), support system and preparation time.

A full-fledged monolith will cost much more, its construction will require much more effort and time, but the structure will stand for centuries. The thickness of the concrete in it will be twice the same characteristic of the colleague. But this option is not suitable for every floor. For example, it makes no sense to put it at the level of the basement, because. concrete will be poured just like that.

If interfloor ceilings are installed on iron beams, each of them will be twice as thin, but its second half will be compensated by the strength of the metal. In this case, the design will not stand idle less than the previous one, but it will be much easier to create something from it. This type will suit any modern design. In addition, concrete, reinforcing rod and plywood will take much less.

Preparation for work

• sheet A3;
• pencil with eraser;
• plywood laminated;
• hammer with nails;
• only;
• supporting system (wooden beams 100 * 100 and metal spacers from 2 mm thick).

This concrete floor is installed exclusively as reinforced concrete slabs between the first and second floors, but not at the level of the basement or attic. The fact is that it makes no sense to put it at the basement level, and when installed above the second floor, it will already turn out to be excessively heavy. But in order for the results of the work to be of high quality, it is necessary to follow the order and a clear sequence in each step.

1. Drawing up a work plan. At this stage, the device of the future scene of action looms, all load-bearing walls are determined and a selection of materials is made. But, as a rule, the set is standard, and everything is calculated so that you can make a purchase in advance. For the perimeter of the scene, you should take the outer side of the wall of the floor, because. the floor must be firmly on its base. Do not allow deviations, tk. they can result in insufficient strength when the concrete is already poured. Concrete should always be taken of the same brand and in no case should it interfere. This rule is independent of the level.
2. Formwork manufacturing. In its manufacture, first of all, it should be taken into account that the arrangement of all joints must be perfect. Each mm must be in a horizontal plane. The side panels will rise 0.3 m above the formwork level. In no case should you nail the side panels to the edge of the pallet, because. a solution of concrete under pressure can tear them out and all work will have to be started over again. All fastenings occur exclusively in the vertical part of the slab.
3. At this stage, a support system will be installed, consisting of wooden beams and metal braces, which can be interchanged if desired. Wooden beams are laid at the rate of 1 pc per 1 m², while spacers - 1 pc per 2 m². With this ratio, you can not be afraid that the ceiling will collapse. Do not forget that the pressure on each of them will be about 500 kg, and even more at the time of pouring (due to the impact energy when concrete falls). After the entire system is installed, you should go to each individual beam and check it again for stability. After that, you need to climb the formwork itself and walk along it with a firm step. There should be no reaction, as if it were a walk down the street. If deviations are felt, then they must be found and redone, otherwise the concrete will make its way down.
4. If all is well, then you can proceed to the last part of the preparation. Waterproofing is carried out in two ways: using roofing felt or plastic film. The material is laid on the formwork, leveled and pressed with something massive, so that it not only does not fly away, but does not even change its shape. Under concrete, it is better to use roofing felt, because. it has great strength and insulation parameters.

Slab reinforcement

• reinforcing rod А500С;
• soft wire;
• roulette.

At this stage, work will be done on reinforcement.

1. The first step is to decide on the reinforcing rod. It must be strong enough, but at the same time not have an excessively large weight, so that the reinforced concrete structures are kept at a height. The best option is A500S. When calculating, it must be taken into account that a double crate is laid, which significantly increases material costs. It is produced as follows: the rods are laid out end-to-end to the wall in parallel with a step of exactly 0.5 m, after which exactly the same level of rods is laid perpendicular to them. Each of their intersections is tightly connected with a soft wire. The work is very long, but necessary.
2. After the first crate is completed, the second is done in exactly the same way, but you should not tie them together. It is also worth remembering that each of them has a level. The lower one should be 25 mm above the formwork level, and the upper one should be exactly the same below the upper pouring bar. To do this, improvised brackets should be bent from the same rod, which will be installed in the amount of 1 piece per 4 m², and all reinforcement will be tied up on them.
3. Once the installation is complete, you can start testing. The process will not take long, but you will need to check each rod for stability, and then shake all the reinforcement. If nothing has moved, we can assume that the work has been done in good faith, but if deviations appear, they should be immediately eliminated and only then concrete should be poured.

Pouring concrete for a slab

• concrete grade 400 and above;
• automixer with hose;
• supporting system (wooden beams 100 * 100 and metal spacers from 2 mm thick);
• only;
• shovel;
• bayonet shovel;
• polyethylene film;
• water;

1. Before you start pouring, you should remember that you should not even start preparing concrete yourself, because. for a 10 * 10 slab, 28.5 m³ will be required, and it will be difficult even for a whole team of builders to do it with their own hands in a day. Here, automixers with a hose for concrete supply are called to the rescue. When ordering, you should know in advance what the volume of the drum is (most often it is 8-9 m³). With this knowledge, it will be easier for you to calculate the amount of material needed.
2. This step may require the help of 1-2 people. In this case, the filling will occur quickly and without stops. During the pouring of the floor, one person must continuously move along the formwork and direct the concrete in different directions. This is required in order to make the pressure on the formwork uniform. If there are no assistants, then from time to time you will have to stop the pouring process and take up the shovel yourself. Each layer should be plowed to release the collected air. This will have a very positive effect on the quality of the filled plate. The lowest level must be plowed very carefully, otherwise the waterproofing material may be damaged. It will be great to interfere during the process, because. he will have to constantly step over so as not to stumble.
3. When the concrete is poured, you should cover everything with plastic wrap and leave it like that for 27-29 days. During half of this time, one should not forget about wetting the plate with water so that it can fully gain its strength.
4. After the specified time, the supporting system is removed, the polyethylene is removed, and the formwork is dismantled with a crowbar. The result is a perfectly smooth surface on the underside and a slightly uneven top. This is corrected later on immediately. With the right approach, such reinforced concrete slabs will not have a single deviation.

Monolith installation technology

• beams (I-beams);
• concrete grade 400 and above;
• laminated plywood 20 mm and thicker;
• roulette;
• reinforcing rod А500С;
• soft wire;
• roulette;
• automixer with hose;
• shovel;
• bayonet shovel;
• polyethylene film;
• water;
• hammer with nails.

This technology allows you to install the slab not only between the 1st and 2nd floors, but also on top of the basement. It is lighter and thinner, but no longer has the same strength parameters, although it has a number of other advantages. Partially the scheme will be similar.

1. In this case, the first step will not be the formwork for concrete, but the beams. They are mounted whenever possible through the narrow parts of the room, if it is not square. During installation, it should be borne in mind that, on average, the length of one beam is 6-8 m, and this can create significant discomfort if you do not insure yourself in advance with an additional load-bearing partition. Each subsequent I-beam technology prescribes to be located at a distance of 1 m from the previous one.
2. Formwork is installed on the beams, the height of which is not 0.3 m, but 0.15-0.2 m. This is due to the fact that at this stage the basic supporting structure already exists.
3. The second difference will be the supporting system of the future floor, which will now require 1.5 times less, i.e. for every 1.5 m one wooden beam, and for 3 m one metal spacer.
4. The third significant difference is reinforcement. The reinforcement lies with just one crate exactly in the center. All connections occur in exactly the same way.
5. Then everything ends in the same way as a full-fledged monolith, regardless of whether it is the level of the fourth floor or the basement. It is important to pour the concrete carefully as even though the future is reinforced with I-beams, the flow of concrete can break through.

Beams can be used for your personal purposes - wiring, niches or anything else where space may be required. From below, it is convenient to sheathe them with plasterboard, because. they are basically on the same level and profile guides are no longer required. Under the condition of the basement from below, through the beams, it is best to carry out lighting that fits perfectly into these conditions.

Device calculation methods

The volume of concrete is considered the easiest - area * height-5% (reinforcement). For a slab mounted on beams, the formula is completely similar. Based on the results, 100 * 0.3-5% \u003d 28.5 m³. Based on average automixers - 4 pcs. The concrete solution itself is mixed in the ratio of 1 part concrete, 3 parts sand and as much water as needed.

Beams are more difficult to calculate than concrete, because often they have to be joined. But if we approach the calculation relatively roughly and imagine that the joints turned out with zero losses, but with an additional spread outside the building, then it is ideal to use 6 m each. In this case, it turns out that it is necessary to calculate prefabricated double beams, then the formula will come out 10 * 6 * 2=120 m (10 beams, each of which consists of two 6 m each).

Modern technologies make it possible to calculate the construction of a concrete slab down to the last nail. So, in the manufacture of formwork, nails are driven in pairs every 0.5 m along the entire perimeter. The vertical formwork is only 0.3 m, but, nevertheless, this place will require additional strength, because of which 2 pairs will be driven into each rib. In total, the construction of formwork for one floor will require 40 * 2 * 2 + 4 * 4 \u003d 176 pieces.

Filling a monolithic floor slab is not the easiest, but a truly universal and time-tested method. In this article, we will talk about the main structural features and stages of the floor installation, as well as the types of formwork, including fixed formwork.

Building typology and scope

The main scope of monolithic ceilings are buildings with load-bearing walls made of brick, 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 the mechanical bonds, embedded reinforcement is released from the inside of the crown by 40–50 cm. 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, with independent design, there is practically no point in making an overlap 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 corrected by including in the supporting structure I-beams steel beams laid on a concrete-leveled masonry surface of the 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. The reinforcement density, in turn, depends on the maximum allowable load and resistance to cracking. Avoiding special cases, we can give a general example of a design that demonstrates full compliance with 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:

1. Plastic sheets of reusable formwork.
2. Moisture resistant plywood 17–23 mm thick.
3. 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 fixed, using profiled sheets for this, orienting them with a narrow shelf 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 of the total thickness of the slab. 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 inch board slanted braces. 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 on all sides. 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.

• Preparation for work
• Stages of pouring a monolithic floor slab
• Summing up the work on the installation of the plate

When building a private house, each person faces a number of difficulties that have to be overcome.

To date, a monolithic ceiling is the best way to make a partition between the floors of a house under construction.

One of the biggest difficulties is pouring a monolithic floor slab after the construction of the first floor.

For a monolithic slab, you must first install the formwork.

There are, of course, alternative options, but the plates are not durable, and the tree is not durable. This is what serves as a weighty argument in the direction of a more expensive and painstaking version of the work yourself.

On average, the actual production time is 40 days, 30 of which are passive and 10 are active. But if several people work at the same time, then the active period of pouring the slab can be reduced by 3-4 days. When doing this kind of work, you need to clearly follow a step-by-step action plan and not deviate from it even for a day - this will save time and money.

Preparation for work

• sheet A3;
• pencil and eraser;
• ruler;
• roulette;
• laminated plywood 20 mm or thicker;
• nails not shorter than 50 mm;
• a hammer;
• supporting system - metal spacers, wooden beams not less than 100 * 100;
• only polyethylene.

To begin with, it is worth preparing on all fronts for work and purchasing everything you need, and getting what you already have from the storerooms.