Monolithic section in the ceiling. Monolithic sections between floor slabs

They are laid with 15 mm seams, that is, almost end-to-end. Regulatory literature prescribes the construction of monolithic sections with reinforcement with a distance between slabs of 300 mm.

To seal the seams between floor slabs, you must use concrete with quick-hardening Portland cement or Portland cement grade M400 or higher with fine aggregate. The grain size of the aggregate should not be more than a third of the gap between the slabs and three-quarters of the clear size between the reinforcing bars. Plasticizers and setting accelerators must be added to the concrete mixture.

If you get a standard seam between slabs with a width of 10-15 mm, then usually a reinforcement bar is laid at the bottom of the seam, which is arranged in the form of a “cone”, and filled with mortar.

We seal non-design joints up to 300 mm

In case The width of the seams between adjacent slabs does not exceed 300 mm; sealing such a seam is relatively simple, there are several ways to fill the seams to choose from.

Method 1

At the bottom of the adjacent slabs, using spacers, we install a board or sheet of plywood that bridges the gap - this is formwork;
You can lay a piece of roofing material or film on top of the formwork, then there will be no traces of concrete left on the formwork, and it can continue to be used;
Fill the gap between the plates with mortar;
We wait for the concrete to gain strength within 3-4 weeks and remove the formwork.

Method 2

If it is not possible to bring the formwork from below, you can do permanent formwork made of galvanized roofing steel 0.8-1 mm thick according to the size of the gap between the plates, resting on the upper edge of the slab (trough). The profile of the side surface of the slabs will provide additional expansion and rigidity to the monolithic section.

Method 3

Another way to seal seams with permanent formwork is from strips of steel with a thickness of 4 mm and a width of 5 cm, make mounting parts according to the gap profile, as in the previous case, resting on the front surface of the slabs, lay these mounting parts every 0.5 m along the length of the slab. On the bottom (in the plane of the lower edge of the slabs) we place a strip of galvanized roofing steel, plywood or plastic, and concrete it. This method ensures reliable adhesion of the monolithic section to the slabs.

Method 4

If you come across a pair of defective slabs with incorrectly positioned side locks, when the recess is at the bottom, they can be installed next to a gap of 2-3 cm. Place the formwork from below using method 1 and pour concrete through the provided gap.

Monolithic sections with a width of more than 300 mm

If the gap between the slabs is from 100 to 300 mm, we construct a monolith with reinforcement. Options are also possible here.

Option 1

Used when formwork from below is not possible.

We install load-bearing beams with a cross-section of 40x100 mm on the edge, in increments of 1 m, resting on adjacent slabs;
We attach the formwork panels to the load-bearing beams with wire twists;
Closing the formwork roofing material or film;
We install the reinforcement cage on the glasses so that the reinforcement is 30...50 mm above the formwork;
We are concreting.

Option 2

If it is possible to secure the formwork from below, you can use reinforcement to construct the supporting structure.

We construct the formwork;
We make mounting parts from A1Ø8…12 reinforcement (depending on the width of the gap to be bridged), taking into account that there must be a distance of at least 30 mm between the bottom of the formwork and the reinforcement;
We lay protective material on the bottom of the formwork;
We install mounting parts;
We lay reinforcement or reinforcement cage;
We are concreting.

Do not settle for filling the gap between the wall and the slab with lightweight concrete cellular blocks (foam concrete, expanded clay concrete, etc.) - they do not have the required load-bearing capacity. Taking into account the arrangement of furniture along the walls, this section of the floor is subject to a large load, this will lead to the destruction of the blocks and the need for costly repairs of the floor.

The areas between the wall and the slab are sealed in the same way.

This story tells not only about sealing seams, but also about anchoring the slabs to each other:

Sealing the ceiling seam from the bottom side

Inter-tile seams - rustications are filled with concrete during installation, then the ceiling is primed, puttyed and painted, unless other finishing is provided.

Sequence of sealing rusts

Before concreting The seams are thoroughly cleaned of dust and mortar residues with a wire brush., for better adhesion of the solution to the slab, you can prime the side surfaces.

The prepared fresh concrete solution is unloaded into a container and delivered to the work site;
If the width of the rustication is small, the filling is carried out at one time, if the width of the area is large - in several layers, but no more than after 2...3 hours;
A concreting area of small width is bayoneted; for a large one, it is compacted with a vibrator;
For the first week, the surface of the monolith is moistened with water daily;
After 28 days, the formwork is removed.

Uneven shrinkage of the house

It's unpleasant when cracks appear on the ceiling. This often happens due to::

Uneven settlement of the building;
Incorrectly selected brand of concrete;
Poor quality concrete.

Let us dwell on the causes of uneven precipitation. It may occur in the following cases:

Structural defects - incorrectly designed foundation;
Foundation construction without taking into account geology, soil freezing depth and groundwater depth;
Poorly performed work on the construction of the foundation and masonry of walls;
Poor quality building materials.

To understand the reason for the appearance of cracks, it is sometimes necessary to order a construction inspection.

Decorative ceilings

A protective layer of concrete 30-50 mm thick should ensure that there are no rust stains on the ceiling from the reinforcement, but sometimes this layer is ineffective. From seeing stains on the ceiling, traces of leaks and rust cracks the best remedy– installation of a suspended, false or suspended ceiling.

Decorative ceiling – best solution if necessary, level the ceiling surface. It will cover all construction flaws and give completeness to the interior. If you want to reduce the height of the room, arrange multi-level or suspended ceilings from plasterboard, acoustic boards or combinations of various materials.

In rooms of low height, false or suspended ceilings are used. Here is the champion - suspended ceiling, which “eats” only 3-5 cm of the room’s height.

Every problem finds its solution. Sealing the seams between, even with large widths, does not pose a major structural or technical problem. From the proposed options it is easy to choose the one that suits your specific case.

Construction of a private house is a complex and labor-intensive task, within which it is necessary to perform various types of work. For example, it may be necessary to fill a monolithic section between floors due to the fact that it is not possible according to the design to form a ceiling entirely from slabs. This happens very often in cases of forming flights of stairs or when it is necessary to lay various communication elements between the slabs. It is quite possible to form a monolithic section between the slabs with your own hands. Although this work is labor-intensive, it is quite doable if you adhere to all building codes and rules.

In the process of forming a monolith section between the floor slabs, it is important to correctly perform following works:

install supports and form formwork;
form a reinforcement mesh;
prepare concrete mixture;
pour concrete correctly.

Correct execution of these types of work will allow you to create a durable and reliable site monolith between the floor slabs in the required place.

Required materials and tools

Considering that work on the device concrete area floors consist of different stages, for each of them it is necessary to prepare a number of materials. The list of such materials may vary due to various factors, including the distance between the slabs that needs to be poured. The standard list looks like this:

plywood or boards to create a direct surface for pouring mortar and side formwork, construction film;
wooden beams or metal channels to create a horizontal support on which plywood or a plank pallet will be laid;
timber (120-150 mm), wooden beams or channels to create load-bearing supports under the formwork platform;
reinforcing bars (15-25 mm), wire for tying, metal chairs for installing reinforcing bars at the required height (reinforced mesh can also be used);
cement M400, sand, crushed stone, water for mixing concrete mortar;
concrete mixer;
circular saw for cutting beams, boards, plywood, as well as metal reinforcing rods;
a shovel, a bayonet tool, a trowel or a rule for leveling the surface of the floor area between the slabs, protective film to cover this area.

The amount of all materials depends directly on the distance between concrete slabs needs to be covered and how much area the monolithic section of the floor occupies as a whole. Typically, in private houses, such a section of flooring is not very large, so its formation is not too challenging task. However, at the same time, you should still adhere to clear phasing and rules for working with building materials and structures.

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Stages of work on forming a monolithic section between floor slabs

The monolithic section of the floor between the slabs is formed in approximately the same way as any. Given the small area of such a site, the work, of course, is simplified, but it is necessary to adhere to all building codes and regulations. Therefore, no matter what distance between concrete slabs is poured, all stages of work must be carried out carefully, on which the reliability of the monolithic structure created independently will depend.

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Installation of supports and formwork

First, we form the formwork for the monolithic section, which must have such mechanical and strength characteristics as to hold a large mass of concrete solution for a long period of time, which will dry for quite a long time.

Installation of formwork is carried out as follows:

We form the bottom of the formwork. To do this, you can first take a sheet of plywood or boards and stuff them onto the beams used as load-bearing elements for the bottom. The distance between floor slabs required for filling in a private house is usually not very large. In this regard, forming the bottom of the formwork is very simple. Before forming the reinforcement grid, it is advisable to cover the bottom with construction film or even simple roofing felt.
On both sides, the lateral boundaries of the monolithic section will be floor slabs. The third is usually a wall. Therefore, the side of the formwork will require the use of one simple board. Even if you need to install a side formwork board on both sides, this will also not be difficult.
We place vertical supports under the beams or boards used as the main retaining elements of the bottom and secure them in such a way as to completely eliminate the possibility of the formwork bottom slipping off the load-bearing vertical supports. Often they even use a unifork for this. However, in private construction conditions, without special supporting equipment, individual parts of the formwork structure can be fixed to each other using nails, staples, etc.
It is extremely important that the bases of the load-bearing supports of the formwork rest firmly on the plane of the floor. To do this, you may need to compact the soil, lay down some tile or board material, etc. It all depends on what floor is on the construction site at the time of creation of the site monolithic ceiling.

Having created a reliable formwork and made sure of its strength, you can proceed to the next stage of work.

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Formation of reinforcement grid

No matter how small the monolithic area created between the floor slabs is, it must be reinforced. If the distance between the floor slabs is more than 1.5 meters, then it is advisable to use reinforced mesh in addition to reinforcing bars. If the gap is small, it will be enough to install two layers of lattice made of rods.

The reinforcement grid is formed quite simply:

We saw off the rods of the required length based on the formation of the reinforcing lattice in increments of 15-20 cm. We tie the rods together using wire. We form two layers of such a reinforcing lattice.
When using reinforcing mesh, we place the first layer of the grid on special metal “cups” that lift the grid 5 cm from the bottom of the formwork. Then we lay the mesh and put another layer of reinforcing mesh on top of it.
A small area between the floor slabs can be reinforced using a conventional frame made of rods - without mesh. The frame needs to be formed in two layers, so that each of them is 5 cm away from the edge of the floor slab. All work can be carried out without a welding machine. simply tying the rods together using ordinary metal wire.

Sometimes you can find a recommendation that reinforcing bars must be inserted into holes pre-drilled in the floor slabs. This should not be done. The created monolithic section will rest on the mounting recesses, which necessarily exist along the side planes of any floor slab model. Such mounting recesses can be longitudinal or round (glass-shaped). They are quite enough to provide reliable support for the monolithic concrete section between the slabs.

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Concrete mixture and its pouring

When starting to mix the concrete solution, you need to make sure that there is a sufficient amount of the materials necessary for it. Having calculated how much volume needs to be poured, it is necessary to calculate how much cement, sand, crushed stone and water will be required to prepare the solution. This is done using a simple formula. For a medium-sized monolithic site, grade 200 concrete is suitable. For private construction, it will be enough to use M400 cement to mix this grade of concrete. The calculation for 1 m³ of such a solution is made from the following mass indicators of all materials:

280 kg of cement M400;
740 kg of sand (approximately 0.55 m³);
1250 kg of crushed stone;
180 liters of water.

It is very simple to calculate how many cubic meters of solution you need in total, because a monolithic section is usually a rectangular parallelepiped. And having prepared all the necessary materials, you can start mixing the solution in a concrete mixer.

When working with a concrete mixer, you should follow a few simple rules:

do not exceed the rated load of the concrete mixer;
install the concrete mixer only on a flat surface;
disembark ready solution first in a separate container, and then evenly transfer it to the desired location.

The last rule is not relevant if the solution will be fed directly from the concrete mixer into the formwork we have prepared under the inter-tile monolith section. In addition, it is very important that no more than 2-3 hours pass between the individual stages of pouring the solution. If the area is not wide, it is best to do everything in one pour. After pouring the mortar into the formwork, it is necessary to level the surface of the filled area with a rule or trowel. It is very convenient to use a flat board for this with emphasis on the floor slabs between which the monolithic section is poured.

Comments:

Building a house is a very labor-intensive task that involves quite a lot of work. For example, pouring a monolithic section between floor slabs is also included in their number, since construction with slabs alone is not possible. This problem, as a rule, arises in cases where it is necessary to lay communication elements or form a flight of stairs. It is worth noting that, adhering to certain rules construction, you can carry out this process yourself.

When creating monolithic sections of the floor, it is necessary to correctly install the support, form the formwork, reinforcing mesh, make a concrete mixture and pour it.

At correct execution of all the listed works, the section of the monolith between the floor slabs will be as strong and reliable as possible.

Materials and tools needed for work

For each stage of work, you need to prepare your own set of materials and tools. Their list may differ only due to some factors, for example, the distance between the slabs that needs to be poured. However, there is still a standard list that includes the following materials:

The area between the floor slabs is filled with concrete and pre-reinforced.

boards that will be used to create side formwork and surface;
wooden beams or metal channels that will serve as support for plywood or a plank pallet;
timber for creating load-bearing supports for the formwork platform;
reinforcement rods, wire with which the bundle will be made, metal chairs;
concrete solution, which is made from sand, M400 cement, crushed stone and water;
concrete mixer;
circular saw, shovel, trowel, bayonet tool and protective film.

As for the amount of material, it depends on the area of overlap that needs to be made, as well as on the area of overlap itself. If we talk about a private house, then in such buildings it is, as a rule, not very large, so it will not be difficult to cope with the work yourself.

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Stages of formation of a monolithic floor section

The formation of the area between the plates is no different from the creation of any other. Despite the fact that the work area is relatively small, it is still worth adhering to construction rules, so all stages of the work must be completed carefully. This is what determines how reliable the monolithic structure will be.

The first thing that needs to be done is to form the formwork for the monolithic section. IN in this case It is necessary to take into account that the concrete solution weighs quite a lot, and besides, it takes a long time to dry, so the strength and mechanical characteristics of the formwork must be such as to hold it for a fairly long period of time.

How to install formwork:

Installation of formwork for a monolithic section between slabs

The bottom is made, for which a sheet of plywood is taken, and beams are placed on it, which will play the role of load-bearing elements. Since the distance between the slabs in a private house is not so large, it is not difficult to make the bottom of the formwork. Before forming the reinforcement grid, we cover the bottom with roofing felt or construction film.
The borders of the monolithic section on the sides will be the floor slabs. As a rule, there is a wall on the third side.
Vertical supports are placed under the bottom holding elements, which are beams. They must be secured so that the bottom of the formwork does not slip off the vertical supports, which are load-bearing. A unifork is used for this, although not always. As a rule, when building a private house, there is no special supporting equipment, so parts of the formwork can be fixed using nails or staples.
An important point in this process is the support of the formwork in the floor plane, which should be as strong as possible. This can be achieved by compacting the soil and lining it with some kind of board or tile material.

After the formwork is ready, and there is no doubt about its strength, we move on to the next stage.

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Making a reinforcement grid

Regardless of the size of the area, it must be reinforced between the floor slabs.

When the distance between the slabs is from 1.5 m, in addition to reinforcing bars, it is best to use reinforced mesh. If the distance is small, you can limit yourself to two layers of lattice made of rods.

The process of forming a reinforcement grid:

The reinforcement grid is laid 5 cm above the bottom of the formwork, the reinforcement is tied together with wire.

The rods must be sawed off to a certain length, taking into account the pitch, which should be about 15-20 cm. Next, the prepared rods are tied together with wire. The result should be two layers of lattice.
When installing the first layer, the reinforcing lattice must be laid 5 cm above the bottom of the formwork, for which the “glasses” are intended. After this, laying a mesh on top, lay the second layer of lattice.
If the area between the floor slabs is not so large, reinforcement can be done with rods without mesh. The frame in this case is formed in two layers, and each of them should be 5 cm away from the edge of the slab. It is worth noting that you should use welding machine This process is not necessary since all connections can be made using metal wire.

Some people advise inserting reinforcing bars into pre-drilled holes in the slabs, but this should not be done. The monolith section will rest on the notches that are present on any model of floor slabs. They can be either longitudinal or round, resembling a glass.

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Making and pouring concrete

Table of proportions of components for the manufacture of concrete.

Before you start mixing the concrete solution, you need to prepare all the necessary components. Since the monolithic section looks like a rectangular parallelepiped, then calculate required quantity solution in cubic meters it won't be that difficult.

After all the components are prepared, you can proceed to making the solution in a concrete mixer, following certain rules:

adhere to loading standards;
the concrete mixer must be installed on a perfectly horizontal surface;
the solution must be unloaded into a special container, and after that - to the required place.

As for the last rule, it can only be broken if the concrete mixer is installed next to the formwork and the prepared solution is unloaded directly into it. Re-filling should be carried out no later than after 2-3 hours. You can make one fill, this is important if the area is not wide. After this, the surface needs to be leveled, for which a trowel or rule is used.

Monolithic sections between floor slabs

Before you decide to make monolithic sections between the floor slabs yourself, soberly assess your capabilities, because this is serious painstaking work. But if you still decide to make a monolith between the slabs yourself, then you will have to go through the following installation stages.

Diagram of a monolithic section.

Surface preparation

At this stage, you have to make sure that you have at hand at the right time necessary materials and tools. Therefore, you need to take care of availability in advance.

So, to make a monolithic section of the floor, you will need the following tools: a hammer drill, wood screws 90 mm long, standard threaded rods 2 m long, nuts, washers, open-end and socket wrenches, Pobedit drills for concrete, wood drills 90 cm long, screwdriver Phillips bits for a screwdriver are of very good quality ( good quality required because the edges of low-quality cue balls wear off very quickly), a hook, a grinder with metal discs, a diamond-coated circular saw (for cutting boards along and across the grain), an 800-gram hammer, a sledgehammer up to 3 kg, nails steel size 120 mm, tape measure #8211 2-3 pieces (tape tapes are necessary for accurate measurements, there must be a sufficient number of them, as they often break and get lost), carpenter's pencil, carpenter's angle 50 cm long, carpenter's stapler with staples, level.

You will also need building materials: knitting wire with a diameter of 0.3 mm for binding frames, reinforcement with a diameter of 12 mm, wire with a diameter of at least 6 mm, cement, gravel, sand, film 100-120 microns thick, boards 50x150 mm, boards 5x50 mm.

It is also necessary to take care of protective equipment in advance, because you and your assistants will have to work dangerously at height among nails, fittings and boards sticking out in all directions. For protection you will need: gloves, closed shoes (construction boots or shoes made of thick fabric such as old-style army combat boots), goggles, cap or helmet.

Design calculations

Calculation of a prefabricated floor slab.

At this stage, you will need to make accurate measurements and calculations so that you know what and how much you will need. First of all, we find out what the floor slabs will be like. To do this, we find out the width of the building and divide it in half, into two equal parts. We immediately determine where the stairs to the second floor will be, which side the rise will be on flight of stairs, and only after that we calculate the dimensions and number of floor slabs.

The length of floor slab #8211 is the width of the house divided by 2.

There are three widths of the floor slab standard sizes: 80 cm, 1 m 20 cm, 1 m 50 cm.

Don't forget to take into account the 7 cm gap between the floor slabs! The absence of a gap between the plates will complicate their installation and may subsequently cause deformation.

Monolithic section between two slabs 980 mm wide (download drawing in dwg format)

Sometimes you have to make wide monolithic sections between the floor slabs. They must be calculated according to the current loads. The drawing shows a monolithic section with a width of 980 mm, supported by two hollow core slabs. The conditions for such a monolithic section (loads, principles of reinforcement, etc.) are described in detail in the article Monolithic section between two prefabricated slabs.

Monolithic section between two precast slabs

Such a monolithic section acts as a slab supported by adjacent precast slabs. For this purpose, it is equipped with working fittings curved by a trough, the diameter of which depends on the width of the section ( effective length slabs of this area) and floor loads. Longitudinal reinforcement is structural; it creates a reinforcing mesh, but does not carry loads. An anti-shrink mesh made of smooth small-diameter reinforcement is also laid along the top of the wide monolithic section.

The figure shows examples of reinforcement of two monolithic sections in housing (without any additional loads in the form of heated floors and brick partitions).

As you can see, there are areas different widths, but when setting the goal of creating a wide monolithic section resting on slabs, you should always check whether the floor slabs will withstand it. This is the most important point in the design of monolithic sections. The load-bearing capacity of floor slabs varies (from 400 to 800 kg/m2 - excluding the weight of the slab).

Let's say we have two prefabricated slabs 1.2 m wide, between which there is a monolithic section 0.98 m wide. The load-bearing capacity of the slabs is 400 kg/m2. i.e. one linear meter such a slab can withstand 1.2*400 = 480 kg/m.

Let's calculate the load per 1 linear meter of the slab from a monolithic section with a thickness of 220 + 30 = 250 mm = 0.25 m. The weight of reinforced concrete is 2500 kg/m 3. The safety factor for the load is 1.1.

0.25*1.1*2500*0.98/2 = 337 kg/m.

We divided by two, because the monolithic section rests on two slabs, and each of them bears half the load.

In addition to the weight of the monolithic section, we have the load on the slabs from the floor structure (140 kg/m2), from the partitions (50 kg/m2) and the temporary load from the weight of people, furniture, etc. (150 kg/m2). Multiplying all this by the coefficients and the width of the precast slab, and adding the load from the monolithic section, we get the final load on each precast slab:

1.3*140*1.2/2 + 1.1*50*1.2/2 + 1.3*150*1.2/2 + 337 = 596 kg/m 480 kg/m.

We see that the load is greater than the slab can withstand. But if you take a slab with a load-bearing capacity of 600 kg/m2, then one linear meter of such a slab can withstand 1.2 * 600 = 720 kg/m - the reliability of the structure will be ensured.

Thus, you should always check the load-bearing capacity of the slabs depending on the dimensions of the monolithic section, the width of the slab and the loads acting on it.

Monolithic floor section with an oblique angle. Reinforcement frame for a slab with a bevel. Concrete work for a monolithic slab with a bevel. Curing and maintaining concrete.

Reinforcement works SNiP 3.03.01-87 Load-bearing and enclosing structures, GOST 19292-73. Instructions for welding reinforcement joints and embedded parts reinforced concrete structures SN 393-78. Guidelines for the production of reinforcement works. And other active ones regulatory documents.

Concrete works should be carried out in accordance with the requirements and recommendations SNiP 3.03.01-87 Load-bearing and enclosing structures.

Concrete mix composition. preparation, acceptance rules, control methods and transportation must comply GOST 7473-85 .

During construction work reinforced concrete monolithic structures should be guided by the requirements SNiP 3.03.01-87 Load-bearing and enclosing structures and the relevant sections of the safety regulations given in SNiP III-4-80. working drawings and instructions for the work execution plan.

1. Monolithic floor section with an oblique angle (UM-1).

In houses. where construction is planned with corner wall transition at an angle not 90°, as usual, but, for example, 45° - floors are being carried out in monolithic version .

You can, of course, take an ordinary reinforced concrete slab and jackhammer knock out the desired bevel of the slab and cut the reinforcement.

But this is fraught with the fact that if the reinforced concrete slab is made with a stressed reinforcement frame (and this is most often done in reinforced concrete factories - such a frame requires less reinforcement consumption), then in such a stripped-down form the slab will lose its load-bearing capacity. Or maybe right away burst during such a circumcision.

NOTE: Prestressed reinforcement frame- this is a frame whose rods clamped in a special form. and then, heating, pulling to the required size.

Further it welded with transverse frames. poured concrete and dried in a steam chamber. Trimming rods from the fixed form was performed already when the slab was in finished form. Those. reinforcing bars in concrete taut like guitar strings. Well, if the string breaks, you know what happens.

Therefore, everything that does not fit into standard sizes industrial reinforced concrete products and structures, running in monolithic version at the construction site of the house. In our version monolithic slab is continuation of national teams reinforced concrete slabs .

2. Reinforcement frame for a slab with a bevel (UM-1).

Manufacturing reinforcement frame and mesh should be carried out according to the drawings and have an exact location elements to be welded. Replacement provided for by the project reinforcing steel by class, brand and assortment is agreed upon with the design organization.

Technological manufacturing process reinforcement cage provides:

straightening and cutting steel fittings, wires. supplied in coils with diameter 3…14 mm And in rods diameter 12…40 mm on rods of measured length
editing(bending) and butt welding rods to the required size
welding meshes and frames
consolidation assembly(welding and wire knitting) volumetric reinforcement blocks
transportation and installation frames at a construction site.

Reinforcement frame of a monolithic section UM-1 running according to the dimensions indicated in the diagram (see figure). And it consists of mesh S-2 And two reinforcement cages K-1. interconnected reinforcing rods from the same steel A-III .

Reinforcing mesh necessary cook spot welding . For frame and mesh used fittings according to the indicated table 1.

Table 1: Specification of reinforcement for the frame of a monolithic floor slab.

Creating a monolithic section between the slabs with your own hands

- Installation of supports and formwork
- Formation of reinforcement grid
- Concrete mixture and its pouring
- Final Recommendations

Construction of a private house #8211 is a complex and labor-intensive task, within which it is necessary to perform various types of work. For example, it may be necessary to fill a monolithic section between floors due to the fact that it is not possible according to the design to form a ceiling entirely from slabs. This happens very often in cases of forming flights of stairs or when it is necessary to lay various communication elements between the slabs. It is quite possible to form a monolithic section between the slabs with your own hands. Although this work is labor-intensive, it is quite doable if you adhere to all building codes and regulations.

If you need to lay various communication elements between the slabs, you can form a monolithic section between the slabs with your own hands.

In the process of forming a monolith section between the floor slabs, it is important to correctly perform the following work:

install supports and form the formwork
form a reinforcement mesh
prepare concrete mixture
pour concrete correctly.

Correct execution of these types of work will allow you to create a strong and reliable section of the monolith between the floor slabs in the required location.

Required materials and tools

Considering that the work on constructing a concrete floor section consists of different stages, it is necessary to prepare a number of materials for each of them. The list of such materials may vary due to various factors, including the distance between the slabs that needs to be poured. The standard list looks like this:

A horizontal formwork support is placed on wooden beams.

plywood or boards to create a direct surface for pouring mortar and side formwork, construction film
wooden beams or metal channels to create a horizontal support on which plywood or a plank pallet will be laid
timber (120-150 mm), wooden beams or channels to create load-bearing supports under the formwork platform
reinforcing bars (15-25 mm), wire for tying, metal chairs for installing reinforcing bars at the required height (reinforced mesh can also be used)
cement M400, sand, crushed stone, water for mixing concrete mortar
concrete mixer
circular saw for cutting beams, boards, plywood, as well as metal reinforcing rods
a shovel, a bayonet tool, a trowel or a rule for leveling the surface of the floor area between the slabs, a protective film for covering this area.

The amount of all materials depends directly on the distance between the concrete slabs that needs to be covered and the overall area occupied by the monolithic section of the floor. Typically, in private houses such a section of flooring is not very large, so its formation is not too difficult a task. However, at the same time, you should still adhere to clear phasing and rules for working with building materials and structures.

Stages of work on forming a monolithic section between floor slabs

The monolithic section of the floor between the slabs is formed in approximately the same way as any monolithic floor. Given the small area of such a site, the work, of course, is simplified, but it is necessary to adhere to all building codes and regulations. Therefore, no matter what distance between concrete slabs is poured, all stages of work must be carried out carefully, on which the reliability of the monolithic structure created independently will depend.

Diagram of a monolithic section.

At this stage, you have to make sure that you have the right materials and tools at hand at the right time. Therefore, you need to take care of availability in advance.

So, to make a monolithic section of the floor, you will need the following tools: a hammer drill, wood screws 90 mm long, standard threaded rods 2 m long, nuts, washers, open-end and socket wrenches, Pobedit drills for concrete, wood drills 90 cm long, screwdriver, cross-shaped cue balls for a screwdriver of very good quality (good quality is required because the edges of low-quality cue balls wear off very quickly), hook, grinder with metal discs, diamond-coated circular saw (for cutting boards along and across the grain), hammer 800- gram, sledgehammer up to 3 kg, steel nails measuring 120 mm, tape measure - 2-3 pieces (tape tapes are necessary for accurate measurements, there should be a sufficient number of them, as they often break and get lost), carpenter's pencil, carpenter's angle 50 cm long , carpenter's stapler with staples, level.

Design calculations

Calculation of a prefabricated floor slab.

At this stage, you will need to make accurate measurements and calculations so that you know what and how much you will need. First of all, we find out what the floor slabs will be like. To do this, we find out the width of the building and divide it in half, into two equal parts. We immediately determine where the staircase to the second floor will be, on which side the flight of stairs will rise, and only after that we calculate the dimensions and number of floor slabs.

The length of the floor slab is the width of the house divided by 2.

The width of the floor slab comes in three standard sizes: 80 cm, 1 m 20 cm, 1 m 50 cm.

We calculate the required size and number of floor slabs, taking into account the fact that there should be a gap of 7 cm between the slabs. After everything has been calculated and we know exactly the required size and number of floor slabs, we order them from the manufacturer or from suppliers of building materials.

Attention!

Don't forget to take into account the 7 cm gap between the floor slabs! The absence of a gap between the plates will complicate their installation and may subsequently cause deformation.

Manufacturing of formwork

Formwork installation diagram.

To make formwork, we take 50x150 mm boards and sew them into a 40 cm high board. One board (1 rib of the future formwork) will use 3 boards. The result is a rib 45 cm high, where 40 cm is the height of the future floor beam and 5 cm is the required margin. They are sewn together with transverse pieces of boards 5x50 mm and 40 cm long. These boards, called lyapukhi, are placed along the entire length of the shield every 40-50 cm. Remember: the first and last lyapukhi should be no closer than 10 cm from the edge of the edge of the shield. We fasten the bolts to the boards with self-tapping screws 90 mm long using a screwdriver at the rate of 3-4 self-tapping screws per 1 board being sewn. Then we align the edges of the shield circular saw using a carpenter's angle.

You will need 3 of these prefabricated panels; they will become the ribs of the formwork.

Installation of formwork

Formwork installation diagram.

To complete this stage of work, a team of 3-4 people will be required.

To make assembly easier, we place one shield as a base. We install a spacer under each bolt so that nothing bends under load.

We attach the ribs to the base of the formwork. We fasten the ribs taking into account how wide we need the beam. Beams of three sizes are allowed: 35, 40, 45 cm. With the required width of 35 cm, both side ribs are placed flush. With a required width of 40 cm, only one edge of two prefabricated panels is installed flush. If you need a beam 45 cm wide, the ribs are attached without using this technique. Everything is fastened with self-tapping screws.

As a result, we ended up with a box of three prefabricated panels in the place where the future beam will be located.

Figure 4. Types of attachment of ribs to the base. A – 35 cm, B – 40 cm, C – 45 cm.

Now we prepare spacers from the reinforcement. They will be needed in order to maintain the required size of the beam and prevent bevels. We simply cut the reinforcement into pieces of the required length (35, 40 or 45 cm).

After this, we proceed to upholstering the resulting box with film from the inside, using a carpenter's stapler with staples. This is necessary in order to prevent unnecessary water loss from the concrete and to avoid the appearance of sinkholes. If this is not done, the concrete will lose a lot of moisture along with sand and cement. After drying, gravel will appear heavily on the outer edges of the beam. The surface of the beam will be completely covered with strong roughness and irregularities, bumps and depressions, the so-called shells. Such a beam will be of poor quality and will have to be redone.

Installation of prefabricated metal structures

Reinforcement frame diagram.

Let's start knitting the frame on the ground. We make 8 veins of a given length from the reinforcement (the length of one vein is equal to the length of the future beam).

Now we make clamps from M-6 wire that are bent by hand. From a single piece of wire you need to make a square with a given length of its sides. So, for a beam measuring 35x35 cm you need a clamp with sides of 30 cm, for a beam 40x40 cm we make a clamp 35x35 cm, for a beam 45x45 cm - a clamp 40x40 cm. These sizes of clamps are necessary so that after it is installed in the formwork it does not touch its walls . Remember: the minimum distance between the formwork wall and the clamp should be 2.5-3 cm, no less!

This is necessary so that in the end it is not visible on the surface of the beam. metal parts clamp. If metal appears on the surface of the beam, then it is in this place that corrosion of the metal and destruction of the concrete, and therefore the beam itself, will begin.

The ends of the clamp are connected with an overlap, that is, there should be an overlap of the ends of the clamp, which are fastened to each other with a double knitting wire with a diameter of 0.3 mm.

The wire is folded in half to form a double knitting wire. This is the wire that should be used to tie the ends of the clamp.

Knowing that the clamps should be located along the entire length of the beam at a distance of 40-50 cm from each other, it is easy to calculate their required number.

We assemble the frame. To do this, we tie 2 strands to each side of the clamp with double knitting wire at an equal distance from the bends and between each other. We place the clamps on the cores 40-50 cm from each other. The distance between the clamps must be maintained.

We place the finished frame in the installed box, being careful not to damage the film. If suddenly the film is damaged, then it’s okay, just fill the hole with another piece of film and secure it with a stapler.

Sometimes, for various reasons, it is necessary to make veins from pieces of reinforcement different lengths. There is nothing wrong with this; construction technology allows it. Simply take another piece of reinforcement and overlap it with double tying wire over the junction of the two sections of the vein, allowing the overlap to be 60cm in each direction. This immediately explains why builders prefer to make veins from solid pieces of reinforcement rather than assemble them from pieces. After all, if you assemble from pieces of different lengths, you will end up with a strong overrun building material. Moreover, this work is carried out when the frame is already inside the box.

Do-it-yourself monolithic ceiling diagram.

Then we take a wood drill and, taking into account the fact that the concrete pressure comes from below, we make holes equal to the diameter of the stud, 15-20 cm from the bottom of the box. We make 1 through hole at the bottom of each blooper. We cut the studs to the length we need.

The length is calculated as follows: the width of the support beam + two thicknesses of the board + two thicknesses of the bolt + two extra threads for screwing on the nuts and washers. We insert the resulting pins into the box.

Now we take pre-prepared pieces of reinforcement - spacers. We install them on top of each stud. We tighten the studs until the spacers lightly stop so that they hold.

We take a level and level the formwork vertically to the ground so that it does not move after compression. All deviations in one direction or another are eliminated using side struts. Installation of studs and installation of spacers is one of the important prefabricated stages of the structure.

After installing the spacers, check everything again with a level, only then attach all the support boards to the formwork with nails or self-tapping screws.

Now let's start hanging the frame. To hang the frame, you need to tie it to the studs. The easiest way to do this is with a height template - a small board measuring 2.5x2.5x30 cm. It’s simple: place a height template under each clamp and wrap it to the pin where it touches with double knitting wire. After fixing the last clamp, the frame will be suspended in the air.

After that, check and inspect everything. Do not allow the film to break or the clamps to touch the walls of the box. Then we fill the transverse slats for sewing the formwork boards together. From the bottom of the base, measure the height of the beam and drive nails along the entire length of the box at this height. These nails are beacons; concrete will be poured along them.

Now we check the strength of the lower and side struts; they should be able to easily support a decent weight. When in doubt, add more supports. Remember: concrete has high density. The slightest mistake and the structure will collapse under the weight of concrete.

Once you are sure that you did everything correctly, then feel free to pour the concrete.

For the manufacture of beams, cement of the M300 or M350 grade is used, which is best purchased ready-made, since the beam must be poured at one time without interruption. If this is not possible, hire a large concrete mixer to mix the entire required volume of concrete on site in one go.

In 3-5 days, in good weather, the concrete will dry; in bad weather, the drying process will take longer.

After the concrete has completely dried, you can begin to dismantle the wooden formwork and install the floor slabs themselves.