Construction of houses

Reinforcement of the floor slab: step by step instructions

The most used overlapping in the construction of individual low-rise buildings are reinforced concrete products with a hollow structure. However, for their installation, lifting equipment is required, which affects the total cost of the work. In addition, ready-made platforms are used for houses with simple shapes..


Some developers prefer to make their own reinforced concrete floors. This method is optimal for objects with irregular geometry. Which, in turn, allows you to deviate from standards and erect structures that are complex in terms of architecture.

Reinforcement slab photo

Benefits of floor slab reinforcement

The reinforced platform, made taking into account technological subtleties, will last for more than a dozen years. When pouring, flat (without seams) ceilings and the same floors are obtained, which do not need expensive and time-consuming interior decoration.

Among the advantages are:

  • the weight. Such a structure weighs significantly less compared to finished reinforced concrete slabs, however, this factor does not affect its strength. But it allows you to reduce the load on the foundation and use lighter building materials;
  • strength. An amazing tandem of materials as different as concrete and iron creates a solid foundation. The platform is used for overlapping large-span and heavily loaded structures;
  • reliability. Concrete structures are highly resistant to multidirectional loads due to the use of reinforcement. They can withstand loads from 500 to 800 kg per square meter;
  • fire resistance. The materials used are themselves non-flammable. The monolithic plate does not support combustion and is able to withstand exposure to an open flame for a long time;
  • price. The cost of overlapping will definitely not exceed the cost of the factory product. The final price is determined by the area to be equipped.

What is floor slab reinforcement

  • The use of this technology gives wider possibilities in terms of interior layout. This makes the platform very solid. It easily withstands high loads, does not burn and does not contribute to the development of insects, fungi and other pathogenic bacteria.

  • The work is carried out according to certain rules. Building materials are purchased from well-known suppliers, because the presence of defects is unacceptable. Only by adhering to the technology can we talk about the corresponding design strength of the finished platform. Otherwise, the overlap may deform and lead to the destruction of not only the interfloor slab, but also the entire building..
  • Filling of floors is carried out by means of a removable formwork, in which the working reinforcement is located. Metal rods are tied together with a knitting wire or connected by a welding machine.
  • The rigid metal frame is positioned so that it is completely submerged in the concrete mass. Thus, the reinforcement will maximally take all the load on itself, and the solution, in turn, will prevent the flow of oxygen, which has a detrimental effect on the metal..

When drawing up the reinforcement scheme for the floor slab, the installation of auxiliary reinforcement to strengthen the sections is taken into account:

  • at the center of the future platform;
  • touching the monolith with columns, interior walls, arches, etc .;
  • where the loads are concentrated (when installing a fireplace, heavy equipment, etc.);
  • contact of the ceiling with openings (exit for stairs to the upper floor, passage for ventilation or chimney pipes and other systems).

Tips for reinforcing a monolithic floor slab

  • The calculation of the thickness of the reinforcement of the floor depends on its length. If the distance between the bearing supports is 5 m, then the thickness of the concrete platform should be 170 mm. That is, the calculations use a ratio of 1/30. However, a structure with a thickness of less than 150 mm is not allowed for use..

Floor slab reinforcement drawing

  • With a minimum floor thickness, metal elements are stacked in one layer. If this parameter is greater, then two.
  • For the solution, concrete M200 (not lower) is used. This brand combines good performance and affordable price. Compressive strength class is 150 kgf / cm2.
  • The diameter of the steel rods varies from 8 to 14 mm. With a two-layer arrangement of metal rods, the diameter of the rolled metal of the lower row should be larger than the upper one. Here you can use a factory-made mesh with cells of 150×150 mm or 200×200 mm.

  • The formwork is constructed from planks and / or moisture resistant plywood. The supports are securely fixed, because the weight of the structure to be poured can reach 300 kg per square meter. It is better to use telescopic racks-jacks as supporting elements, which allow you to set the required height with high accuracy. Each support is capable of withstanding a load of up to 2-2.5 kg.

Reinforcement of the floor slab with your own hands


  • This design is removable, therefore it is recommended to use those materials that can be used in the future. Edged boards of 150×25 mm are suitable here. However, they will not provide a perfectly flat surface of the future ceiling, since a certain error is allowed in the thickness of this lumber. It will be easy to hide all irregularities under the plaster layer, especially if the installation of suspended ceilings is planned..
  • In cases where it is fundamentally important to have a flat surface, then instead of boards, laminated plywood with a thickness of 22 mm is used. But such a formwork will cost a decent amount. The following option will be much more economical: the same edged boards act as a basis, and plywood with a thickness of 8-10 mm is laid on top of them.
  • The formwork is equipped with boards (150×50 mm), which are attached around the perimeter of the room. Transverse bars are mounted with a step of 600-800 mm, it is under them that vertical supports or telescopic racks are installed strictly at the level.

  • On top of the frame, boards with dimensions of 150×25 mm are tightly laid out. It is not necessary to fasten to the base or to each other, otherwise at the end of the work (after pouring and drying the concrete), great difficulties will arise when disassembling the formwork. If necessary, plywood sheets are laid on top of the boards.
  • So that the material used for the formwork can be used for other purposes, the structure is covered with a dense plastic wrap. The canvases are overlapped (at least 200 mm) only on the base of the formwork without going to the ends, during work it is important to avoid material jams.
  • If the slab serves as a decking under the roof, then instead of side boards, it is better to lay out the sides of bricks or cellular blocks with a height corresponding to the thickness of the concrete layer.

After the slab is made, the formwork is dismantled and not broken. In this connection, all fasteners must be located on the outside of the structure.


  • To form a slab for small spans, you can knit the mesh yourself. It is advisable to lay the rods along their length without breaks. If there is a need for a garter, then the metal elements are mounted with an overlap of at least half a meter.
  • The intersection points of the perpendicularly spaced rods are held together by means of a wire or a welding machine. Spot welding is relevant when using large diameter fittings. Thin rods become thinner during the welding process, which leads to a decrease in the strength of the metal, and therefore to the loss of the bearing capacity of the finished slab.

  • For knitting, you can use a special hook. However, certain skills will be required here, in addition, wire twists will still have to be twisted. Therefore, within the framework of the construction of a private house, you can get by with ordinary pliers..
  • Ready-made metal cards can greatly facilitate the process. They are laid with an overlap – at least 2 cells, that is, the same 400 mm is obtained. Without fail, they are fixed to each other by means of a wire..
  • The metal frame must not lie directly on the bottom of the formwork. It is installed on stones, broken tiles with a thickness of at least 40-50 mm. If the design thickness of the reinforced concrete slab is more than 150 mm, then another lattice is knitted by the same method. The second reinforcing layer should be at a distance from the first, but at the same time completely overlap from above with concrete mortar.
  • Places with increased load are reinforced with additional rods. Bending of the reinforcement should be done mechanically. Heating the metal changes its structure, which leads to a loss of plasticity, and as a result – cracking of the workpiece.

  • Knitting wire twists are harvested in a fairly simple way. The coil is pre-fastened with tape at 3-5 equidistant points, the distance between which should correspond to a convenient length for twisting. Using a grinder, the bay is cut along the areas marked with tape.

Concrete mortar

  • The process of casting the formwork is greatly facilitated by a special technique. At the plant, plasticizers, water repellents and other additives are added to the concrete solution, which improve the physical and technical characteristics of the finished solution..
  • However, there is not always a place for a concrete mixer to drive in, and it is impractical to order it for a small area. Therefore, in some cases it is necessary to knead the solution manually. The stove should be poured in one step, here you need the help of 2-3 people.
  • For mixing one part of concrete is taken: 3 parts of sifted sand; 5 pieces of crushed stone or gravel; water 20% of the total volume of bulk components.
  • First, all dry components are mixed, then the required volume of water is added. It is problematic to do this manually, so a concrete mixer is used here, which is taken from neighbors on the site or rented from construction firms.
  • After mixing, the solution is used immediately. The dried mixture cannot be diluted with water, unfortunately it will have to be thrown away. Therefore, it is important to carry out all the preparatory work in the required volume and immediately before pouring, mix the concrete solution..

  • In the process of pouring, a vibrator must be used. If there is none, then you can get by with a uniform tapping of the hammer on the open mesh and wooden formwork elements..
  • Hardening, the concrete mass shrinks; with a fast process, microcracks can form in the slab. To avoid their appearance, the surface is regularly moistened and covered with plastic wrap, which slows down the evaporation of moisture. Wetting is carried out by means of a spray, not a direct stream..
  • Concrete will reach its strength in 4 weeks. To make sure that the slab is completely dry, a piece of roofing material is laid out on a small area and left for a day. A dark spot under a sheet of waterproofing material indicates that the plate has not dried out, which means it is not ready for use..

By following simple rules and using quality materials, you can achieve amazing results even for a novice builder. Such an overlap for a private house, garage or other building is the best option. Especially if there is no access to the facility under construction for special equipment. Moreover, the reinforced floor provides more opportunities than ready-made concrete products. Factory products of standard sizes are used for structures based on right angles. And this technology is ideal in cases when you want to get away from standard solutions and build a house without reference to square or rectangular shapes..

Floor slab reinforcement video