Preparation, reinforcement and pouring of a monolithic floor. Making a concrete floor with your own hands

Comments:

Do-it-yourself pouring of a floor slab is an operation that almost every builder has to perform own house. Despite the fact that the work is laborious, after the device you will receive:

a flat surface of the ceiling, in which there will be no seams;
a plate of any configuration and thickness;
a durable slab that can withstand high loads and reinforces the overall structure of the house.

Conditions for pouring a monolith

It should be taken into account that concrete floor can only be done in buildings with strong walls. Its pouring in houses with wooden walls is unacceptable, and in buildings with partitions made of lightweight materials, a monolithic slab can be poured only after additional steel or reinforced concrete supports are installed under it. In addition, buildings with such platforms must be built on stable ground and a strong foundation. If the building you are building does not meet these conditions, you should refuse to fill the floor slab with concrete.

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Formwork installation

Before pouring the ceiling between floors, above the basement, under the attic, etc. it is necessary to build a reliable formwork that can withstand the mass of poured concrete. After it hardens, the weight of the monolith will be distributed along the walls on which it rests. In addition, reinforcement will give strength to the plate, but it will not be able to hold the liquid solution in any way.

So, the concreting of the sites is divided into 3 stages:

Formwork installation.
Construction of a reinforcing lattice.
Solution pouring.

It is necessary to start with the installation of the formwork, since it will be necessary to accurately align it horizontally, and it will be difficult, and in some cases completely impossible, to do this after laying the reinforcement.

formwork structure under concrete pad- a complex structure, the installation of which is difficult to carry out alone. First, you should talk about a lighter version of its device, which the builder can handle on his own. Such formwork can only be installed in rooms with a small area, in which racks are not required to support its central part or 1 row will be enough. Such formwork can be arranged in rooms where the distance between the walls does not exceed 3 m.

For its construction you will need:

bars 50x100 mm;
bars 50x150 mm;
anchor screws or bolts 10x100 mm;
self-tapping screws;
moisture resistant plywood with a thickness of 18 to 22 mm;
thick polyethylene film;
hydraulic level;
chopping cord with chalk;
roulette;
perforator;
drill driver;
jigsaw.

Please note that the beams of both tiers of formwork will be laid on edge. Longitudinal (50x100) will be mounted on two opposite (and longer) walls, and transverse (50x150) - on top of them. When taking measurements, keep in mind that the distance (c) from the longitudinal bars to the ceiling is calculated by the formula: c \u003d a + b (a is the width of the cross beam, b is the thickness of the plywood).

To determine the horizontal on the walls, use a level, cord and chalk. Drill holes for the anchors in the longitudinal beams. The step between them is 50 cm. Make marks on the walls and drill holes in them. Fasten the bars. Lay jumpers on them at a distance of 0.5 m from each other. Additionally, check the levelness of the plane with a level and tighten the longitudinal and cross bars self-tapping screws. Cover the crate with plywood.

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Formwork on racks

Another way to install formwork is to mount it on racks. For them, you can use bars with a cross section of at least 100x100 mm. True, the exact derivation of the horizontal when using such supports will be difficult. In addition, these posts must be additionally reinforced with braces, which should connect the lower and upper parts of adjacent posts so that they are in stable balance. It is quite another thing when height-adjustable racks are used as supports, equipped with tripods for greater stability. If possible, rent these devices.

Installation is carried out as follows:

The extreme rows of supports are installed at a distance of 20 cm from longer walls.
The distance between the racks in a row is 1 m.
The distance between rows (longitudinal bars) is no more than 2 m.
Racks are aligned vertically and along the upper ends.
Beams are placed and fixed on them.
The transverse bars are laid and fastened in increments of not more than 50 cm.
The level checks the horizontal plane under the plywood. If necessary, the height of the racks is calibrated.
Plywood is laid.

Now it is necessary to hem the sides of the formwork with self-tapping screws. The optimal height of the side panels is the thickness of the overlap. It should be 1/30 of the span length (the distance between long walls), but not be thinner than 15 cm. Remember to install a fence in places where there will be openings.

A waterproofing layer is laid at the bottom of the formwork. Thanks to him, when laying concrete, water will not seep through the seams, and the ceiling will turn out to be more even. It should be noted that thin polyethylene is not suitable for the role of a waterproofing agent. When pouring, it will shift, which will create unnecessary irregularities on the ceiling. You need to use a dense film or bituminous roll materials.

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Reinforcing cage installation

When building a ceiling with your own hands, you should not forget about laying the reinforcement, without which its operation is impossible. To create a frame are used:

reinforcing bars of class A3 with a thickness of 8 to 16 mm;
knitting wire for connecting fittings.

At a height of at least 1.5 cm from the formwork, the first layer of the frame is laid. The size of its cells is no more than 20x20 cm. It is desirable that the length of each rod is enough from wall to wall. If the reinforcement is short, then 2 rods are connected with an overlap exceeding their diameter by 40 times.

The frame will be weakened if the location of the connections of short rods in adjacent rows is the same. It is necessary to ensure that the joints are as far apart from each other as possible. Gaps between rods are allowed only in the place where an opening in the floor is provided. By the way, the reinforcement should border the perimeter of the future hole. Under the remaining edges of the frame, there must be load-bearing structures. The second layer of the frame of the monolithic slab is laid in the same way. It is located at a certain height above the first, but the grate must be recessed in the thickness of concrete at a depth of 1.5-2 cm.

It must be said that steel pipes, laid parallel to each other between 2 frames, will lighten the weight of a monolithic floor slab. Their cross section depends on the distance between the gratings. If both ends of the pipe rest on the walls, then the structure will acquire additional rigidity. The pipes must not reach the side panels of the formwork. For laying in the frame, it is not necessary to use new products.

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How to pour concrete

Now everything is ready for, which you need to cook from:

fresh cement grades M500 and M400 (released no more than 1 month ago);
sand;
rubble.

The last two components of the mixture must be purchased separately in order to accurately maintain the proportions of the components of the concrete solution. As for the binder component, cement deteriorates its properties after a month of storage, so it is not advisable to purchase it for future use.

The optimal volumetric proportions of the components of the mixture are given in the table.

Grade of cement	Cement (in parts)	Sand (in parts)	Crushed stone (in parts)
400	1	1,7	3,2
500	1	2,2	3,7

By adding cement, sand and crushed stone in such quantities, you will get grade 300 concrete, which has optimal characteristics not only for the construction of a monolithic floor slab, but also for creating foundations and other critical structures.

Water is added after mixing the binder with sand. Its volume is about half the volume of the dry components of the mixture, but the exact amount of liquid to be poured depends on how wet the sand is. Crushed stone is poured into the mixture after adding water.

Overlappings are solid reinforced concrete structures reinforced type. Their use is relevant for increased weight loads, especially in high-rise buildings. In private construction, their main advantages include the ability to reduce installation costs by independently performing individual or all stages of work with minimal involvement of special equipment. The technology is considered time-consuming; to eliminate errors, the calculation of the slab should be entrusted to specialists. The parameters obtained must be taken into account when preparing the main project of the house.

Conventionally, everything is divided into prefabricated (solid or hollow, manufactured at the factory), often ribbed (cellular type with sections of lightweight material or empty blocks) and monolithic. The latter are valued primarily for the absence of seams, this option is chosen when concreting multi-storey buildings, pouring floors or delimiting floors in individual buildings. Depending on the design and installation methods are divided into: beam, beamless (the most popular variety with a smooth surface in the construction of private houses), with fixed formwork (at the same time it acts as a heat-insulating layer) and laid on a steel deck. The latter are valued for reducing labor intensity and the possibility of reducing thickness and weight.

Features and benefits of a monolithic floor

The pluses include:

1. Strength and solidity (lack of seams), and, as a result, ensuring a uniform load on the foundation and bearing walls.

2. Possibility of leaning on columns. This gives more freedom in the planning process compared to the option of laying prefabricated floor slabs from standard size prefabricated elements.

3. Safe arrangement of the balcony without the need for additional supports due to the solidity of the main horizontal structure.

Calculation of the slab, drawing up a reinforcement scheme

Ideally, the design is entrusted to specialists, they will help you choose the option with correctly distributed loads, which is optimal in terms of “reliability-cost of building materials”. The initial data for self-calculation are the dimensions of the floor with the obligatory consideration of the width of the supporting platforms. The thickness of the monolith is selected based on maximum value longitudinal span (the ratio recommended for beamless structures is 1:30, but not less than 15 cm). For floors within 6 m, the minimum is 20 cm, over 6, options are considered with their reinforcement with stiffeners. In varieties of the beam type, the step of the supports is taken into account (respectively minimum height is found by dividing it by 30).

The calculation of the slab begins with determining its own weight: the average (2500 kg / m3) is multiplied by the thickness of the floor. Live load rate (weight of furniture, equipment and people) for residential buildings- 150 kg / m2, taking into account 30% of the stock, it is increased to 195-200. The total, maximum possible load is obtained by adding these values.

To check the section of the reinforcement, the maximum bending moment is calculated, the formula depends on the way the weight is distributed. For a standard beamless floor supported by two load-bearing walls М max = (q l2)/ 8, where q is the total load, kg/cm2, l2 is the span width. This formula is the simplest, in the absence of reinforcement in the zones of maximum compression of concrete or uneven distribution of weight, it becomes more complicated.

To check the cross section of the reinforcement, a coefficient is calculated that takes into account the design resistance of building materials (reference values depend on the selected mortar strength class and steel grade). The obtained value corresponds to the minimum allowable metal area in the cross section of the plate. It is compared with the preliminary one; if it is exceeded, the circuit needs to be strengthened (reducing the cell pitch or using rods with a larger diameter).

Due to the complexity of the calculation, specialists are usually trusted; when passing it, a chess pattern is selected from two grids (lower and upper) with a cell pitch of 20 × 20 cm and a rod thickness of 10-14 mm (hot-rolled steel). Both reinforcement is provided in the center of the monolithic slab, areas with increased loads and places of contact with supports, as well as a margin for overlapping walls (depending on the strength of building materials - from 150 mm for brick to 250 for cellular concrete). Longitudinal and transverse rods, if possible, are laid inseparably, if this condition is violated, they overlap - at least 40 cm.

The main stages of installation

Laying begins with the calculation and purchase of building materials (ideally, project data is used). Formwork structures are being prepared: panels made of thick moisture-resistant plywood, metal or plastic, beams and telescopic supports (1 pc / m2), equipment for preparing, supplying and compacting concrete, a tool for bending reinforcement and special supports. If necessary, an armored belt is laid along the perimeter of the load-bearing walls, such a need arises when erecting ceilings in a house made of aerated concrete.

The main steps include:

Assembly and installation of formwork.
Placement of the armored carcass.
Filling a monolithic slab with concrete, compaction and leveling.
Moisture maintenance of the solution, covering, dismantling of the formwork after 28 days.

1. Requirements for supports and shields.

Installation involves pouring concrete into a sealed horizontal formwork, preference is given to special collapsible structures. In principle, it is easy to make shields yourself from plywood with a thickness of at least 20 mm (it is better not to use boards due to difficulties in fitting). A prerequisite is the installation of telescopic metal racks(during the construction of the floor of the first floor of the house, they are replaced by stationary supports). In their absence, replacement with logs with a diameter of at least 8 cm is allowed, but one should be prepared for problems when adjusting the level.

To support the shields, a crossbar is laid - a longitudinal beam with a cross section of at least 10 × 10 cm, if necessary, the formwork is reinforced with transverse elements (this situation most often occurs when working with homemade products). The shields are laid without gaps, the edges tightly rest against the wall. During installation vertical structures the value of approach to carrier systems is taken into account. To eliminate the risk of leakage, the bottom is covered with a film, sealed factory reusable varieties are lubricated to facilitate the removal process. The stage ends with a level check, deviations are not allowed.

2. What should be taken into account when reinforcing?

Reinforcement with metal is the main requirement of the technology. The distance from the edge of the concrete to the metal is at least 25 mm. The joints are tied with wire with a cross section of 1.2-1.5 mm, welding is not allowed. For meshing, pre-prepared clamps are used: made of steel with a thickness of at least 10 mm, with an interval of up to 1 m, similar elements are placed at the ends. Reinforcement of a monolithic reinforced concrete floor ends with the laying of connectors that ensure uniform load perception on the entire system - after 40 cm near the walls, after 70 from it, with a subsequent step of 20.

3. Nuances of concreting.

The main requirement of the technology is the continuity of the process; ideally, the solution is ordered at factories and poured using the appropriate equipment. The recommended thickness of the concrete layer is 20 cm, which in most cases coincides with the height of the floor itself. Minimum stamp is M200, in order to strengthen thermal insulation properties and lightening the weight, part of the coarse-grained high-strength filler can be replaced with expanded clay, but this method requires approval by specialists (strength checks).

Holes for the supply of communications and ventilation ducts are laid before the start of pouring, drilling of a frozen monolithic slab is a violation. The stage ends with the obligatory compaction of concrete using internal vibrators. The rules for caring for the surface are generally standard, but it is impossible to water the structure abundantly with water, unlike the foundation or vertical walls, it is wetted more accurately.

Rates

The cost of filling when contacting professional firms varies from 4,000 to 9,000 rubles / m3 (subject to the use of the customer's formwork). The total cost depends on the chosen reinforcement scheme, the height of the future slab (from the ground level or from the mark of the previous horizontal support) and its thickness, the method of placement (on columns or load-bearing walls), and the total amount of work. The list of services of construction companies includes the installation and dismantling of formwork structures, the assembly of the reinforcement cage according to a project prepared in advance (paid separately), continuous concreting and care of the laid mixture: watering, covering, and, if necessary, warming up. The advantage of turning to professionals is the mandatory quality control carried out at the end of curing.

The advantages of laying flooring with your own hands include a reduction in the cost of paying for work - up to 30% at least. For pouring, simple building materials are used - concrete and reinforcement, saving on them is unacceptable. The volume of the solution is calculated based on the thickness and area of the slab, the length and weight of the metal - according to the reinforcement scheme drawn up in advance. Renting formwork structures is expensive: the minimum price per m2 is 400 rubles per month (you can’t rent it earlier).

To additional costs when doing work with their own hands, they include the need for special equipment and containers for raising the solution up (bucket shoes and a crane or concrete pump). This is not a problem when arranging solid floors on the basement floors of a house, but in other cases, you cannot do without the appropriate equipment. This is due to the main requirement of the technology - a continuous process of concreting, monolithic floors with individual patches, frozen in different days, are inferior in quality to those filled at a time. Minimum costs when performing all stages, they independently amount to 3200 rubles per 1 m2 with a plate thickness of 20 cm.

Monolithic overlap

A monolithic concrete floor is a complex building element, the design of which is still better to entrust the architect. The problem is that it is one thing when only a small part of the ceiling is poured with a monolith, and the rest is laid with factory slabs. It is quite another thing - it is a monolith of the entire floor. If marriage, hack-work with the walls, errors become visible gradually and usually without serious problems, then an incorrectly constructed monolithic overlap is a risk of tragic consequences.

Purchased hollow core slabs ceilings have a factory load capacity, eg 800 kg/m 2 . And here is the exact maximum load on a monolithic slab, only the architect's project can tell. And besides, this load will be correct only if the construction of the monolith was done without errors and from materials with characteristics in accordance with the project. For this reason, in IZHS, people who pour a monolithic ceiling without a project often play it safe and take a large margin of safety.

The construction of a monolithic concrete floor begins with formwork installations. Moisture-resistant laminated plywood is usually used, or, if possible, you can rent a special formwork for monolithic ceilings. From below, the formwork is supported by special telescopic jack stands(they can also be rented) or homemade props from a bar.

The telescopic rack has a maximum load, which depends on the type of rack, its installation height and mounting method. Therefore, the permissible load can vary from 600 to 7000 kg per rack. With a reinforced concrete density of 2500 kg / m 3 one square meter a poured slab 20 cm thick will weigh 500 kg. You can calculate what is the minimum number of racks needed to overlap. You also need to remember about the weight of the formwork.

Longitudinal beams are placed on top of the racks, and on top longitudinal beams cross beams are placed so that the plywood lies on them as rigidly as possible and does not sag. The upper surface formed by the formwork should be as even as possible. Along the perimeter of the future slab, formwork boards from boards are installed to the height (thickness) of the slab.

After installing the formwork knitted reinforcing cage- a square grid in one or two layers. In most cases, the size of the square in the grid is 20x20 cm. To increase the bearing capacity of the slab, it is common to increase the diameter of the reinforcement, rather than reduce the size of the square.

Whether there will be reinforcement in one or two layers - this is set in the calculation by the architect! The lower reinforcing mesh is usually "more important" than the upper one, because it takes the main tensile loads. Even if the house is being built without a project, then for the correct calculation of the reinforcement of a monolithic floor, it is still better to contact the designer. The diameter of the reinforcement depends on the loads and the width of the span: with different input data, it is possible to use reinforcement from 8 to 20 mm.

The armature is knitted with wire. If the length of the reinforcing bars is not enough, then the reinforcement is overlapped.

The thickness of the monolithic slab usually chosen at 20 cm. Also popular is the recommendation not to make a monolithic floor with a thickness of less than 1/30 of the span, otherwise the deflection of the slab increases.

To get a binding for the armature protective layer of concrete, the connected reinforcing cage must be raised above the formwork using plastic supports. Thus, the concrete will surround the reinforcement from all sides. The reinforcement should also not touch the side formwork board, a protective layer of concrete is also needed there.

After finishing the knitting of the reinforcing cage poured concrete. You need to pour everything at once, without stretching the process, so you need to buy factory concrete. The poured concrete must be leveled and compacted.

If the upper surface of the wall, on which the monolithic slab rests, has voids (for example, warm ceramics), into which water from concrete can escape, then this wall surface must first be rubbed with mortar. Water should not leave freshly poured concrete - there will be cracks!

A frozen monolithic floor needs to be periodically pour water so that the concrete does not crack and gain strength. To prevent water from evaporating, the stove can be additionally cover with foil.

With a question when remove formwork with a monolithic overlap, there is an ambiguity. Many private developers keep the formwork for almost 30 days for a long time. But, for example, in table 5.11 from SP 70.13330.2012 (updated edition of SNiP 3.03.01-87) "Bearing and enclosing structures" it is indicated that when stripping the concrete, the strength of concrete in unloaded monolithic structures should be at least 70% of the design with a span of up to 6 m and at least 80% for a span of more than 6 m. Usually 70% strength is about 3-4 days, depending on concrete, temperature, concrete additives.

The concrete manufacturer or the designer-architect can tell the date when exactly the concrete will gain strength. For reinsurance, many keep the formwork for 2-3 weeks, although this can slow down construction. By the way, professional builders during the construction of monolithic multi-storey buildings, they manage to fill one floor in a week.

Loading a poured monolithic slab significant additional loads (for example, pallets with bricks) are possible only after 21 days.

In a monolithic overlap quite often cracks form, because concrete is an inelastic material, i.e. it cannot stretch. If the cracks are minor, then you should not be afraid of them. Architects designing floors can make a calculation for the formation of cracks.

I note that in this article we were talking about a "normal", flat monolithic ceiling. There is also technology ribbed monolithic ceiling. The slab is poured with "ribs" (i.e. beams) protruding downwards, with which it rests on load-bearing walls or columns. The ribbed floor reduces the use of concrete and, to some extent, rebar; this saves money, reduces the weight of the overlap. Also, a ribbed floor usually allows you to cover a longer span.

However, formwork for a slab with many ribs is a much more labor-intensive process than for a flat slab. In order to save on concrete, not to lose later in permissible load on the floor, it is important to entrust the calculation of a monolithic ribbed slab (as well as a conventional flat slab) to a specialist. Also, do not forget that the ceiling with such an overlap will turn out to be ribbed (as in factory buildings), therefore, to create a flat ceiling, plaster disappears, drywall remains.

General rules for concreting floor slabs

Concrete must be poured quickly and without interruption in the process, this should be taken care of in advance. To do this, you need to consider the submission process concrete mix for overlapping and arrival of mixers at the construction site to the concrete pump or shoe. The process of concreting the floor slab is quite laborious and therefore requires the involvement of a large number workers who will work in units in shifts without a break for lunch. Otherwise, if large delays in the supply occur during operation, the mixture loses its homogeneous properties, which adversely affects the strength of the structure.

If the structure is still very large, and it is impossible to fill the entire volume of the future slab in 1 step, then special concreting working seams are made, in the place of minor load. The seam is either vertical or horizontal, but in no case non-sloping. The working seam is cleaned, and work continues, if it is vertical, then sometimes a chain-link mesh is used for better adhesion between layers.

The horizontal seam practically does not occur when concreting slabs, but it is indispensable when building a bunker and other structures with a very thick layer of concreting.

Before starting concreting work, you should carefully inspect the entire formwork table, the presence of load-bearing and additional racks, and the integrity of the sides. Concreting of floor plinths is a very important process, and if the formwork does not withstand in one place, then the “domino” principle can occur and the entire structure will collapse under the weight of the load of the concrete mixture, which leads to huge material damage and human casualties.

Concreting technology for monolithic floor slabs

To lay the concrete mixture, you will need the following tools:

shovels;
trowels;
vibrators;
rubber boots.

To measure the level of concrete, you should take a probe, usually it is a cross-welded reinforcing cane with a set level of slab thickness, it is used to orientate during the reception of the mixture what is the current thickness of the layer.
Shovels are used for laying the concrete mix, trowels or semi-trucks are used for leveling. Semi-terriers are much less practical for large volumes of concrete mix.

The distance from the tray supplying concrete and the formwork should not exceed 1m so that the concrete is uniform and does not scatter very much on the sides.

Concrete should be laid with a width of 1.5-2 m and a thickness of 15-30 cm, with its compaction. The most suitable compaction method - using vibrators - deep - is needed for large thick structures, surface - for slabs and structures located in the plane of the slab, external - used when working in narrow heavily reinforced structures.

The duration of the vibrator is 30-60 seconds, a sign that the concrete has sat down well is the cessation of concrete subsidence, and the appearance of a film on the surface of the concrete mix. For bulk work, several vibrators are used.

The process of supplying and laying the mixture should be as conveyorized as possible. General scheme such, two workers lay the supplied mixture, one or two people immediately after them with a probe and shovels level it to the desired level. Next comes a worker with a trowel, who brings the surface of the concrete into a mirror state.

Quality control of floor slab concreting

After the concreting of monolithic floor slabs is completed, it is necessary to carry out control. The whole problem is that it is impossible to disassemble the structure earlier than after 2 weeks, because the margin of safety is still insufficient. After removing the formwork, inspect the surface for pores of shells, shells in horizontal structures are much rarer than in vertical ones.

If the air temperature is above 10 degrees, then the plate is covered with damp burlap or thick cloth and constantly watered, keeping it moist, which is necessary for any work with cement mixtures Since the cement dries quickly, in order for it to grip better and be stronger, it should be kept moist at first, especially at high temperatures.

Building your own home is an expensive and troublesome undertaking. One of the stages of construction will be the manufacture or roof of the building.

In a room that is non-residential, 12 cm of thickness is enough for a concrete floor, but if the rooms are still residential, then it is worth increasing it to 15 cm, and also provide additional sound insulation.

The prices are very high and the inability to use crane and non-standard dimensions of the ceiling make you make a slab with your own hands.

How is the pouring of the floor slab done by hand? Can homemade formwork be used?

In low-rise construction, the practice of self-reinforcing and pouring floor slabs with their own hands has become widespread. Monolithic slabs Overlappings have a number of advantages in comparison with other overlapping technologies:

The pressure on the walls is the same around the entire perimeter if a single floor is used.
There is no need to use lifting mechanisms (crane).
A monolithic floor is much stronger than a wooden one, it is fire resistant.
Overlapping can be made non-standard in shape and size.

The sequence of work is as follows: the manufacture and installation of the formwork, and pouring it with a concrete solution, waiting for the concrete to dry completely for at least 30 days.

How to make and install formwork with your own hands?

For fixed formwork in ceilings, either shell slabs or reinforced concrete frames are used. The space between them is filled with hollow elements - blocks (ceramic, lightweight concrete, etc.)

Formwork for release industrial enterprises our country. But the price of such a professional design is very high - about the same as how much the stove itself will cost you along with the work.

The way out is simple: it must be made by hand. To do this, you need to prepare:

wooden boards 50x150 mm;
thin plywood;
wooden bar.

A special tool is not required, but you must have:

wood saw;
a hammer;
axe;
level;
level;
nails.

Boards and plywood, after being used for pouring the floor slab, can be used for the roof. The formwork will stand for about a month, then it will be dismantled. Experienced builders strongly recommend using telescopic racks when pouring the floor slab with their own hands. They are very handy, make the job very easy, it is a reliable tool.

The formwork is strong, because the rack is designed for a weight of 2 tons. At the same time, it is very important to connect and fix the corners firmly and securely. The board does not withstand any competition, because knots and microcracks are not always taken into account. Optional tool to buy, numerous construction firms give formwork and racks for rent. You can only take racks, the price of their rental will be 70-100 rubles. per m area.

Scheme for the design of the ribbed formwork.

The formwork is mounted when doing the work with your own hands after the walls of the basement or first floor are raised to the required height. Installation is carried out in stages:

Racks with tripods should be arranged in rows with a step of 1-1.2 m.
The longitudinal beam must be laid on top of the racks, the racks should be pulled to the required height.
The transverse beam is laid on the longitudinal beam. After that, the timber must be knocked down into a single grid and lay thin plywood.
Only after fixing the plywood, the entire slab should be leveled with a level.

The next stage of work will be reinforcement.

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How to properly reinforce the floor slab with your own hands?

It is very important to correctly calculate the reinforcement and the required thickness of the slab. Depending on the calculated loads, the diameter of the reinforcement is selected. More often it is in the range from 8 to 14 mm. It is recommended to use hot-rolled steel reinforcement of class A3 to ensure the proper strength of the floor slab.

Reinforcement of the plate is made in order to add rigidity to the structure. As improvised materials, an iron rod, a fine mesh for plaster, as well as old iron pipes(can be found at your nearest scrap metal collection point).

Do-it-yourself reinforcement of the slab is done in 2 layers. The first grid is laid in the lower part of the slab, the second one will be laid in its upper part. After the concrete has been poured, the grids must be inside with protective layer from the formwork not less than 1.5-2 cm.

The reinforcement in the mesh must be tied with a knitting wire. In the mesh, the reinforcement itself must be solid. Breaks are not allowed. Cells often have a size of 150x150 mm.

If the floor slabs are small in area, then the cells are made 200x200 mm. If there is not enough length of the reinforcement, an additional one is tied up so that the overlap is equal to 40 diameters of the reinforcement. It is desirable to place the joints of a metal bar in a checkerboard pattern (in a run). The ends must rest on the supporting beams.

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How to pour concrete floor slabs with your own hands?

To prepare concrete you will need:

crushed stone;
sand;
cement brand 400, 500;
water;
shovels;
buckets - 3 pcs.

Recommended proportions when preparing the mortar: 2 buckets of sand, 1 bucket of crushed stone and 1 bucket of cement. It is very convenient to use a concrete mixer, rented. The solution is mixed in a concrete mixer with the addition of water to a consistency resembling liquid sour cream. Such "liquid" concrete is made to perform "spill". It is a thin solution that will fill all the cracks and internal cavities of the plate well.

When pouring large floor slabs, instead of crushed stone, you can take expanded clay, which will allow you to minimize the weight of the structure itself. The cost of such material is very high, so it is better to use crushed stone in small-sized products (it costs much less).

“Spilling” is the initial pouring of mortar into the formwork. The solution should be poured evenly and slowly, no sudden movements should be allowed to prevent distortions in the formwork itself.

After completing the “pouring”, in fact, pouring the first layer, it is necessary to “move” the laid layer with a shovel or other tool. This should be done carefully, with smooth movements along the entire surface of the first layer. These actions will remove unfilled cavities, air bubbles will come out.

Next, we repeat the operation of pouring the floor slab with our own hands with thicker concrete to a level of 10-12 cm, leaving a margin of approximately 2-3 cm to the calculated thickness of the floor slab. Again, it is necessary to achieve uniform filling of the formwork with mortar using a special vibrator or an improvised tool. Concrete needs to set, it will take a couple of days, only after drying and setting can the final pour be performed.