The construction of a private house is a complex and time-consuming 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 to form a ceiling completely from slabs according to the project. This happens very often in cases of the formation of flights of stairs or, if necessary, laying various communication elements between the plates. It is quite possible to form a monolithic section between the plates with your own hands. Although this work is laborious, it is quite doable if you follow all building codes and regulations.
In the process of forming a monolith section between floor slabs, it is important to correctly perform the following work:
- install supports and form formwork;
- form a reinforcing mesh;
- cook concrete mix;
- pour concrete correctly.
Correct execution of these types of work will create a strong and reliable site monolith between the floor slabs in the required place.
Necessary materials and tools
Given that the work on the installation of a concrete floor section consists of different stages, a number of materials must be prepared for each of them. The list of such materials may vary due to various factors, including how much distance between the plates needs to be filled. The default 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 channel to create load-bearing supports under the formwork platform;
- reinforcing bars (15-25 mm), wire for tying, metal chairs for installing reinforcing bars on required height(you can also use reinforced mesh);
- cement M400, sand, crushed stone, water for mixing concrete;
- concrete mixer;
- a circular saw for cutting beams, boards, plywood, as well as metal reinforcing bars;
- shovel, bayonet tool, trowel or rule for leveling the surface of the overlap area between the slabs, protective film to cover this area.
The amount of all materials depends directly on the distance between concrete slabs need to be covered and what area as a whole is occupied by a monolithic section of the overlap. Usually, in private houses, such an overlapping area is not very large, so its formation is not too challenging task. However, at the same time, all the same, one should adhere to a clear phased approach and rules for working with building materials and structures.
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Stages of work on the formation of a monolithic section between floor slabs
A monolithic section of overlap between the slabs is formed in approximately the same way as any. Considering small area such a site, the work, of course, is simplified, but it is necessary to adhere to all building codes and rules. Therefore, no matter what distance between the 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 a monolithic section, which must have such mechanical and strength characteristics that a long period hold a large mass of concrete mortar, which will dry for a long time.
Formwork installation 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 on the beams used as load-bearing elements for the bottom. The distance between the floor slabs required for pouring is usually not very large in a private house. 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 a construction film or even a simple roofing material.
- On both sides, the lateral boundaries of the monolithic section will be floor slabs. On the third - usually there is a wall. So side part 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.
- Under the bars or boards used as the main retaining elements of the bottom, we bring vertical supports and fix them in such a way as to completely exclude the possibility of the formwork bottom slipping from the bearing vertical supports. Often, they even use a unifork for this. However, in the conditions of private construction, without special supporting equipment, it is possible to fix individual parts of the formwork structure with each other using nails, staples, etc.
- It is extremely important that the bases of the formwork bearing supports are firmly supported in the plane of the floor. To do this, it may be necessary to compact the soil, put some kind of tile or plank material, etc. It all depends on the type of floor at the construction site at the time the site was created. monolithic floor.
Having created a reliable formwork and making sure of its strength, you can proceed to next step works.
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Formation of a reinforcing lattice
No matter how small the created monolithic section 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. With a small gap, it will be enough to install two layers of a lattice of rods.
The reinforcement grid is formed quite simply:
- We saw off the rods of the required length based on the formation of a reinforcing lattice in increments of 15-20 cm. We connect the rods together with a wire. We form two layers of such a reinforcing lattice.
- When using a reinforcing mesh, we put the first layer of the grating on special metal "glasses" that raise the grating by 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 floor slabs can be reinforced with conventional frame from rods - without a grid. It is necessary to form the frame 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 by tying the rods with ordinary metal wire.
Sometimes you can find a recommendation that reinforcing bars must be inserted into holes pre-drilled in floor slabs. This should not be done. The created monolithic section will be based on mounting recesses, which necessarily exist along the side planes of any models of floor slabs. Such mounting recesses are longitudinal, round (in the form of a glass). They are quite enough to provide reliable support for a monolithic concrete section between the slabs.
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Concrete mix and pouring
When starting to mix a concrete solution, you need to make sure that there is a sufficient amount of 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 section, concrete grade 200 is suitable. For private construction, it will be enough to use M400 cement to mix this brand 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.
Calculating how many meters of cubic solution you need in total is very simple, because a monolithic section usually represents cuboid. And having prepared everything 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 nominal load of the concrete mixer;
- install the concrete mixer exclusively on a flat surface;
- disembark ready solution first into a separate container, and then evenly transfer it to the desired location.
The last rule is not relevant if the solution is supplied directly from the concrete mixer to the formwork prepared by us under the section of the inter-tile monolith. In addition, it is very important that between separate stages pouring the solution took no more than 2-3 hours. If the area is not wide, it is best to do everything in one fill. After pouring the solution into the formwork, it is necessary to level the surface of the filled area with a rule or a trowel. It is very convenient to use for this a flat board with an emphasis on the floor slabs between which a monolithic section is poured.
Comments:
Building a house is a very time-consuming task, which includes quite a lot of work. For example, pouring a monolithic section between floor slabs is also one of them, since construction from slabs alone is not possible. This problem, as a rule, arises in cases where it is required to lay communication elements or form a flight of stairs. It is worth noting that, keeping 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 mixture of concrete and pour it.
At correct execution all listed works the section of the monolith between the floor slabs will be as strong and reliable as possible.
Materials and tools necessary for work
For each stage of work, it is necessary to prepare your own set of materials and tools. Their list may differ only due to some factors, for example, the distance between the plates that needs to be filled. However, there is still a standard list that includes the following materials:
The area between the floor slabs is filled with concrete, pre-reinforced.
- boards that will be used to create the side formwork and surface;
- wooden beams or metal channels, which will serve as a support for plywood or a plank pallet;
- timber for creating load-bearing supports for the formwork site;
- reinforcement bars, wire, with which the bundle will be made, metal chairs;
- concrete mortar, 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 how much overlap area needs to be done, as well as on the overlap area itself. If we talk about a private house, then in such buildings it is usually not very large, so it will not be difficult to cope with the work on your own.
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Stages of formation of a monolithic section of the floor
The formation of a section between the plates is no different from the creation of any other. Despite the fact that the area of work is relatively small, adhere to building regulations still worth it, so all stages of work must be performed carefully. It depends on this how reliable the monolithic structure will be.
The first thing to do is to form a formwork for a monolithic section. V this case it is necessary to take into account that concrete mortar weighs quite a lot, besides, it dries for a long time, so strength and mechanical characteristics formwork must be such as to hold it for a fairly long period of time.
How the formwork is installed:
Formwork for a monolithic section between slabs
- The bottom is made, for which a sheet of plywood is taken, and beams are stuffed onto it, which will play the role of load-bearing elements. Since the distance between the plates in a private house is not so large, it is not difficult to make the bottom of the formwork. Before forming the reinforcing lattice, we cover the bottom with roofing felt or construction film.
- The boundaries of the monolithic section on the sides will be floor slabs. As a rule, there is a wall on the third side.
- Under the holding elements of the bottom, which are the bars, vertical supports are brought. They must be fixed so that the bottom of the formwork does not slip off the vertical supports, which are load-bearing. For this, a uni-fork is used, although not always. As a rule, when building a private house, there is no special support equipment, so the formwork parts can be fixed using nails or staples.
- An important point in this process is the support of the formwork to the floor plane, which must be as strong as possible. This can be achieved by compacting the soil and lining some kind of plank or tile material.
After the formwork is ready, and there is no doubt about its strength, we proceed to the next stage.
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We make a reinforcement grid
Regardless of the size of the site, it must be reinforced between the floor slabs.
With a distance between the plates of 1.5 m, in addition to reinforcing bars, it is best to use a reinforced mesh. If the distance is small, you can limit yourself to two layers of a lattice of rods.
The process of forming a reinforcing lattice:
The reinforcement grid is laid 5 cm above the bottom of the formwork, the reinforcement is pulled together with wire.
- The rods must be cut to a certain length, taking into account the step, which should be about 15-20 cm. Next, the prepared rods are wired together. The result should be two layers of the lattice.
- When installing the first layer, the reinforcing mesh must be laid 5 cm above the bottom of the formwork, for which “glasses” are intended. After that, having laid the grid on top, the second layer of the grid is laid.
- If the area between the floor slabs is not so large, the reinforcement can be made with bars without a mesh. The frame in this case is formed in two layers, and each of them must be removed from the edge of the plate by 5 cm. It is worth noting what to use welding machine not necessary in this process, since all connections can be made with metal wire.
Some advise inserting reinforcing bars into pre-drilled holes in the slabs, but this should not be done. The section of the monolith will rely on the recesses that are present on any models of floor slabs. They can be either longitudinal or round, resembling a glass.
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Production and pouring of concrete
Table of proportions of components for the manufacture of concrete.
Before you start mixing concrete mortar, you need to prepare all the necessary components. Since the monolithic section looks like a rectangular parallelepiped, then calculate required amount solution in cubic meters it won't be that hard.
After all the components are prepared, you can proceed to the manufacture of the solution in a concrete mixer, observing certain rules:
- adhere to the loading norm;
- 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 violated 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 2-3 hours later. You can make one fill, this is true if the area is not wide. After that, the surface must be leveled, for which a trowel or a rule is used.
Before you decide to make monolithic sections between floor slabs yourself, soberly assess your capabilities, because this is serious painstaking work. But if you still decide to make a monolith between the plates yourself, then you have to go through the following installation steps.
Scheme of a monolithic section.
At this stage, you have to make sure that at the right time you have at hand the right materials and tools. Therefore, oh availability must be taken care of in advance.
So, to make a monolithic section of the floor, you will need the following tools: a puncher, wood screws 90 mm long, standard threaded studs 2 m each, nuts, washers, open-end and cap wrenches, concrete drill bits, wood drill bits 90 cm long, screwdriver, cruciform bits for a screwdriver of very good quality ( good quality required because the edges of low-quality cue balls are erased very quickly), a hook, a grinder with metal discs, a diamond-coated circular saw (for cutting boards along and across the fiber), an 800-gram hammer, a sledgehammer up to 3 kg, steel nails 120 mm in size , tape measure - 2-3 pieces (tape measures are necessary for accurate measurements, there should be a sufficient number of them, as they often break and are lost), a carpenter's pencil, a carpenter's angle 50 cm long, a carpenter's stapler with staples, a level.
Building materials will also be required: knitting wire with a diameter of 0.3 mm for tying 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 the means of protection in advance, because you and your assistants will have to work at a height of injury among nails, rebar 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 berets), goggles, a cap or helmet.
Structural calculations
Calculation of the prefabricated floor slab.
At this stage, you will need to make accurate measurements and calculations in order to know what and how much you will need. First of all, we find out what the floor slabs will be. 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, from which side the flight of stairs will rise, and only after that we calculate the size 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 is 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 everyone has calculated and exactly found out the required size and number of floor slabs, we order them from the manufacturer or from suppliers of building materials.
Attention!
Do not forget to take into account the gap of 7 cm between the floor slabs! The absence of a gap between the plates will complicate their installation and subsequently may cause deformation.
Formwork manufacturing
Formwork installation scheme.
For the manufacture of formwork, we take boards 50x150 mm and sew a shield 40 cm high from them. 3 boards will go to one shield (1 edge of the future formwork). You will get a rib 45 cm high, where 40 cm is the height of the future floor beam and 5 cm is the necessary margin. They are sewn together with transverse pieces of boards 5x50 mm and 40 cm long. These boards, called slippers, are located along the entire length of the shield every 40-50 cm. Remember: the first and last slippers should be no closer than 10 cm from the edge of the shield edge. We fasten slippers with boards with self-tapping screws 90 mm long using a screwdriver at the rate of 3-4 self-tapping screws per 1 board to be sewn. Then align the edges of the shield circular saw using a carpenter's corner.
It will take 3 of these prefabricated shields, they will become formwork ribs.
Formwork installation
Formwork mounting scheme.
To complete this stage of work, a team of 3-4 people will be required.
To facilitate assembly, we put one shield as a base. We install a spacer under each slipper so that nothing bends under load.
We fasten the ribs to the base of the formwork. We fasten the ribs, taking into account the width of the beam we need. Beams of three sizes are allowed: 35, 40, 45 cm. With the required width of 35 cm, both side ribs are flush. With the required width of 40 cm, only one edge of the two prefabricated shields is flush. If you need a beam 45 cm wide, the ribs are fixed without using this technique. Everything is fastened with self-tapping screws.
As a result, we got a box of three prefabricated shields in the place where the future beam will be located.
Figure 4. Types of fastening the ribs to the base. A - 35 cm, B - 40 cm, C - 45 cm.
Now we prepare spacers from reinforcement. They are needed to survive right size beams and prevent bevels. We simply cut the reinforcement into pieces of the desired length (35, 40 or 45 cm).
After that, we proceed to upholstery of the resulting box with a film from the inside, while using a carpentry stapler with staples. This is necessary in order to prevent excessive loss of water from the concrete and to avoid the appearance of shells. If this is not done, the concrete will lose a lot of moisture along with sand and cement. After drying, gravel will show strongly on the outer edges of the beam. The entire surface of the beam will be covered with strong roughness and irregularities, bumps and depressions, the so-called shells. Such a beam will be of poor quality, and it will have to be redone.
Installation of prefabricated metal structures
Scheme of the reinforcing cage.
We start knitting a frame on the ground. We make 8 veins of a given length from reinforcement (the length of one vein is equal to the length of the future beam).
Now we make clamps from M-6 wire, which are bent by hand. From a single piece of wire, it is necessary to make a square with a given length of its sides. So, for a beam measuring 35x35 cm, you need a collar with sides of 30 cm, for a beam of 40x40 cm we make a collar 35x35 cm, for a beam 45x45 cm - a collar 40x40 cm. Such dimensions of the collars are necessary so that after it is installed in the formwork, it does not touch its walls . Remember: 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 collar. If the metal will show through on the surface of the beam, then it is in this place that corrosion of the metal and the destruction of concrete will begin, and hence the beam itself.
The ends of the clamp are overlapped, that is, there must 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, getting a double knitting wire. It is with such a wire that the ends of the clamp must be connected.
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.
Assembling the frame. To do this, we tie 2 wires to each side of the clamp with a double knitting wire at an equal distance from the folds and between each other. Clamps are placed on the cores 40-50 cm apart. The distance between the clamps must be maintained.
We stack finished frame into the installed box, being careful not to damage the film. If suddenly the film is damaged, then it's okay, just close the hole with another piece of film and fix it with a stapler.
Sometimes, for various reasons, you have to make veins from pieces of reinforcement different lengths. There is nothing wrong with that, the construction technology allows it. Simply take another piece of rebar and tie it with an overlap with double tie wire over the junction of the two pieces of vein, with an overlap of 60 cm in each direction. This immediately explains why builders prefer to make veins from whole pieces rebar, rather than assembling them from pieces. After all, if you collect from pieces of different lengths, you get a strong overrun building material. Moreover, this work is carried out when the frame is already inside the box.
Do-it-yourself monolithic flooring scheme.
After we take a drill for wood 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 slipper. We cut the studs to the length we need.
The length is calculated as follows: the width of the support beam + two board thicknesses + two slipper thicknesses + two threads for screwing nuts with washers. The resulting studs are inserted into the box.
Now we take pre-prepared pieces of reinforcement - struts. We install them on top of each stud. We twist the studs until the spacers lightly stop so that they hold.
We take the level and level the formwork vertically to the ground so that it does not lead after compression. All deviations in one direction or another are eliminated with the help of side struts. The installation of studs and the installation of spacers is one of the important prefabricated stages of construction.
After installing the spacers, check everything again with a level, only after that attach everything support boards to the formwork with nails or self-tapping screws.
Now let's start hanging the frame. To hang the frame, it must be tied 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: put a height template under each collar and fasten it to the hairpin at the points of contact with a 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 breaks in the film or contact of the clamps with the walls of the box. Then we fill the transverse rails for stitching the formwork boards. From the bottom of the base we measure the height of the beam and drive in nails along the entire length of the box at this height. These nails are beacons, concrete will be poured over them.
Now we check the strength of the lower and side struts, they should be free to withstand a decent weight. If in doubt, add more supports. Remember: concrete has a high density. The slightest oversight - and the structure will collapse under the weight of concrete.
We made sure that everything was done correctly - then feel free to pour concrete.
For the manufacture of beams, cement of the M300 or M350 brand is used, which is best bought ready-made, since the beam must be poured at a time without interruption. If this is not possible, hire a large concrete mixer to mix all the required volume of concrete on site in one step.
After 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.
Provide for their laying with seams of 15 mm, that is, almost end-to-end. The regulatory literature prescribes the installation of monolithic sections with reinforcement at a distance between the plates of 300 mm.
To seal the seams between the floor slabs, it is necessary to use concrete on quick-setting Portland cement or Portland cement grade M400 or higher on fine aggregate. The grain size of the filler should not be more than a third of the interslab gap and three quarters of the clear size between the reinforcing bars. Plasticizers and setting accelerators must be introduced into the concrete mix.
If a standard seam is obtained between plates with a width of 10-15 mm, then usually a reinforcement bar is laid on the bottom of the seam, which is arranged in the form of a “cone”, and poured with mortar.
We seal off-design joints up to 300 mm
If the width of the seams between adjacent plates does not exceed 300 mm, it is relatively easy to close such a seam, to choose from - several ways to fill the seams.
Method 1
- From the bottom of the adjacent slabs, using spacers, we install a board or a sheet of plywood that bridges the gap - this is the formwork;
- A piece of roofing material or film can be laid on top of the formwork, then there will be no traces of concrete on the formwork, and it can be used further;
- The gap between the plates is filled with mortar;
- We are waiting for the concrete to gain strength within 3-4 weeks, we remove the formwork.
Method 2
If it is not possible to bring the formwork from below, you can do fixed formwork made of galvanized roofing steel with a thickness of 0.8-1 mm according to the size of the gap between the plates, with support on the upper face of the plate (trough). The profile of the side surface of the plates will provide additional spacer and rigidity to the monolithic section.
Method 3
Another way to seal seams fixed formwork – from steel strips with a thickness of 4 mm and a width of 5 cm, make mounting parts along 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. At the bottom (in the plane of the lower edge of the plates) we put a strip of galvanized roofing steel, plywood or plastic, concrete. This method provides reliable adhesion of the monolithic section to the plates.
Method 4
If you come across a pair of defective slabs with the wrong location of the side locks, when the recess is at the bottom, they can be installed next to a gap of 2-3 cm. From below, bring the formwork according to method 1 and pour concrete through the provided gap.
Monolithic sections with a width of more than 300 mm
If the gap between the plates is from 100 to 300 mm, we perform a monolith with reinforcement. There are also options here.
Option 1
Used when formwork from below is not possible.
- We install load-bearing bars with a section of 40x100 mm on the edge, in increments of 1 m, resting on adjacent plates;
- TO load-bearing bars we fasten the formwork panels with wire twists;
- We close the formwork roofing material or film;
- Install reinforcing cage on glasses so that the reinforcement is 30 ... 50 mm higher than the formwork;
- We concrete.
Option 2
If it is possible to fix the formwork from below, it can be used for the device load-bearing structure fittings.
- We build formwork;
- We make mounting parts from reinforcement A1Ø8 ... 12 (depending on the width of the overlapped gap), 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 reinforcing cage;
- We concrete.
Do not settle for sealing the gap between the wall and the slab with lightweight concrete honeycomb blocks(foam concrete, expanded clay concrete, etc.) - they do not have the required bearing capacity. Taking into account the arrangement of furniture along the walls, this section of the floor has a large load, this will lead to the destruction of the blocks and the need for costly repairs to the floor.
The areas between the wall and the slab are sealed in the same way.
This story tells not only about the sealing of the seams, but also about the anchoring of the plates among themselves:
Ceiling seam from the underside
Intertile seams - rustication at installation is filled with concrete, then the ceiling is primed, puttied and painted, if no other finish is provided.
The sequence of sealing rusts
Before concreting the seams are thoroughly cleaned of dust and grout residues with a metal brush, for better adhesion of the mortar to the slab, the side surfaces can be primed.
- The prepared fresh concrete solution is unloaded into a container and delivered to the place of work;
- With a small width of the rust, the filling is performed at a time, with a large width of the site - in several layers, but not more than after 2 ... 3 hours;
- A concreting section of a small width is bayoneted, with a large one it is compacted with a vibrator;
- The first week the surface of the monolith is moistened with water daily;
- After 28 days, the formwork is removed.
Uneven house shrinkage
It is unpleasant when cracks appear on the ceiling. This often happens due to:
- Uneven settlement of the building;
- Wrong brand of concrete;
- Poor quality concrete.
Let us dwell on the causes of uneven precipitation. It may occur if:
- Structural flaws - incorrectly designed foundation;
- Foundation arrangements without taking into account geology, the depth of soil freezing and the depth of groundwater;
- Poorly executed work on the construction of the foundation and masonry walls;
- Poor quality building materials.
To understand the cause of the appearance of cracks, it is sometimes necessary to order a construction expertise.
Decorative ceilings
A protective layer of concrete 30-50 mm thick should ensure that there are no rust stains on the ceiling from reinforcement, but sometimes this layer is ineffective. From seeing stains on the ceiling, traces of leaks and rust cracks the best remedy- the device of a suspended, hemmed or stretch ceiling.
Decorative ceiling - the best solution if necessary, leveling the ceiling surface. It will close all construction flaws and give completeness to the interior. If you want to reduce the height of the room, arrange multi-level or dropped ceilings from drywall, acoustic boards or combined from various materials.
indoors small height perform hemming or stretch ceilings. Here is the champion stretch ceiling, which "eats" only 3-5 cm of the height of the room.
Every problem has its solution. Sealing between, even with a large width, does not constitute a big constructive or technical problem. From the proposed options, it is easy to choose the appropriate one for a particular case.
Even in professional floor layouts, there is often a monolithic section between slabs in buildings of complex configuration. Concreting this piece is much easier than casting a solid slab, since the bottom, upper level are set by default, there is no side formwork, the lower shield is sufficient. One option is to use prefabricated monolithic ceiling SMP.
Technology of a monolithic section of overlap
V individual construction boards are more commonly used standard height 220 mm. This must be taken into account when reinforcing makeshift plot, providing the minimum possible protective layer 15 - 30 mm. If the monolithic section between the floors protrudes above the neighboring ones, an increase in the thickness of the screed will be required when finishing the floors.
Factory floors have voids in which it is convenient to pull the electric cable. V homemade stove communications must be walled up before pouring so as not to hammer concrete later. This technique is often used for the manufacture of hatches. If openings for stairs are cut in slabs made industrial way, the reinforcement scheme is broken, the structure loses bearing capacity becomes dangerous to operate.
formwork
The monolithic section between the plates is poured onto the shield, which must be supported from below with racks. The simplest calculations of lumber sections - the most a budget option for an individual developer, show that boards, timber with minimum dimensions can be used for formwork:
In this case, the structure will support the weight concrete floor without sagging, geometry changes.
A monolithic section between floors by default has a side formwork, which is the ends of reinforced concrete products laid in place. It remains to place the boards under the bottom surface, bringing their edges under the existing PC boards, to control the flatness, the absence of deflection in any direction. To do this, follow the steps:
After that, the remaining posts are mounted between the extreme posts, ensuring the horizontality of the beams, girders, deck boards. When choosing wood of the 2nd grade, the bending strength of the lumber is insufficient. Besides bottom strapping pillars with boards of 25 mm, necessary to prevent shifting during pouring, a similar strapping is additionally used at the level of 1.3 - 1.5 m. All pillars are sewn with an "inch" across, along, forming a rigid spatial structure.
Stackable racks are used to facilitate demoulding:
- they are manufactured less than the design height
- are built up in pieces in the upper part, which is enough to unscrew when dismantling
When stripping, the lower bars of the racks are first dismantled, then the beams with the upper pieces of the racks are removed. After that, the deck with the runs screwed to it is dismantled. In the future, all lumber is suitable for construction truss system. If you choose wood of grade I, you can reduce the cost of the "inch" board for tying the racks in the middle part.
If it is necessary to fix the formwork elements to existing walls it is better to use anchors with metal sleeves. They are easily removed from the masonry after stripping, unlike dowel-nails, the plastic elements of which are almost impossible to remove from the wall.
Deck
At this stage, the monolithic section between the slabs is equipped with a deck over the girders. The edges of the boards lead under the existing floor slabs, the middle lies on the beams, which ensures the rigidity of the structure.
The gaps between the boards are foamed from the inside of the formwork (top), the boards are covered plastic wrap. This will keep water in the concrete, facilitate stripping, and prevent cracking of the floor slab. Plank construction is convenient for wiring engineering systems- holes of any diameter are drilled with crowns, drills without problems in any area.
With a width empty area less than 1 m, technology without racks, beams is often used:
The deck is attracted by wire twists through the beam to the lower planes of the laid plates, reinforced, poured along standard technology. It is not recommended to punch holes for reinforcement in the ends of the slabs, as they weaken the design of hollow PC products. Wire clamps angle grinders are cut off when stripping flush, the part remains inside the monolithic piece.
To increase the overlapping resource, reinforcement not lower than A-III of a periodic section (hot-rolled) with a diameter of 10 - 16 mm is used. The main nuances of reinforcement are:
For knitting the joints of the cells, a wire of 1 - 2 mm is used, the knots are created by manual, mechanical hooks, homemade rigging installed in a screwdriver or a special knitting gun.
The area between the slabs can be reinforced with a ready-made or locally bonded mesh. In the first case, the dimensions of the longitudinal, transverse rods are taken, taking into account 4 cm of the protective layer on each side. Nets are knitted on flat ground, laid on the deck on top of the film on spacers 15 - 30 mm. More commonly used concrete blocks 10 x 10 cm or plastic coasters with cross slots for fittings.
For the top layer, these devices are not suitable due to their small size. Clamps, brackets, tables are used here different forms, designs. The main task of these elements is to support the upper grid in the design position (15 - 30 mm below the plate plane).
Used for bending reinforcement homemade devices. For example, a piece of 50 - 70 cm pipe with a mandrel of 10 - 15 cm welded to one of its edges will provide the required radius (5 bar diameters), and will reduce the effort.
The area between the slabs may contain the input nodes of engineering systems. Mortgages, void formers are installed after or before reinforcement, depending on the location, configuration, size. For example, it is better to mount a 11 cm sewer cross before laying the grids; sleeves for water pipes can be installed at any stage. 
Void formers complex shape necessary for specific communications. Therefore, they are usually made from Styrofoam, Styrofoam, cutting pieces of the same format to achieve the desired length from a 5 cm sheet.
For rigid fixation, the absence of movement of light polymer fittings, polystyrene foam void formers, the following technology is used when pouring the ceiling:
- plugs are put on the fitting
- fixed with screws from below through the deck
- or the plug is screwed on top with screws
- then a fitting is put on it
These self-filled areas can be supported by internal flights of stairs. For them it is necessary:
- release reinforcement of the lower grid
- make a step for supporting the reinforced concrete march structure with a reciprocal seat
- install formwork for stairwell/hatch
For the release of reinforcement, it will be necessary to make cuts in wooden shield jumpers chain saw. Put the board on the reinforcement, passing it into the cuts, foam the remaining cracks. Steps, recesses are created by screwing narrow strips to the formwork from the inside.
fill
Before placing concrete between floor slabs, it is recommended to prime the ends of existing slabs to improve adhesion. The main recommendations for concrete work are:
Concrete is contraindicated in solar ultraviolet, hot dry weather, frost. Covering with burlap, sawdust, sand allows you to wet the surface without destruction. The film protects against sun rays, in winter it provides the principle of a thermos, keeping the heat that forms during the hydration of cement with water.
The brand of concrete is selected in accordance with the standards of SP 63.13330 for reinforced concrete structures:
- density - 1 800 - 2 500 kg / m 3
- compressive strength - from B7.5
Waterproof, frost resistance for structures operated indoors, special significance does not have. At self-manufacturing concrete, it must be taken into account that the probability of cracking is sharply reduced if a filler of various fractions with a continuous series of grains is used. Sand should not exceed 1/3 of the total aggregate volume.
After pouring between the floor slabs, sagging may remain with the newly made section. They are polished with diamond equipment for angle grinders ("grinder") of the plate type. If the project includes a bulk, warm floor, screed, alignment of the joints is not necessary. For better adhesion of two adjacent reinforced concrete structures, strobes can be made in the side faces of the factory plates if the appropriate tool is available.
These recesses are filled with a mixture when laying concrete, two slabs are obtained almost monolithic. The quality of the lower edge of the slab is usually inferior to factory counterparts, therefore, finishing with stretch, level ceilings is more often used. 
This technology is very convenient in the manufacture of hatches or stairwells. These technological holes can be reinforced with rods diagonally located near them, dramatically increasing the strength of reinforced concrete. If you cut a hatch in the factory plate, the integrity is violated reinforcing mesh, which weakens the default construct. This is especially true when the opening is moved to the middle of the slab.
The technology of a monolithic section of a self-made floor allows you to fill voids when laying out slabs without reducing structural strength. Even without pretensioning the reinforcement, the plates have a high resource if the specified requirements are met.