Building your own home with your own hands is a long and difficult process that allows you to save a decent amount on hired workers and rented equipment. One of the problems that a master has to face is the choice and manufacture of an interfloor overlap. Monolithic flooring compares favorably and in many respects surpasses options such as timber and prefabricated reinforced concrete slabs. This procedure is rather complicated, lengthy and expensive. But the invested funds and the efforts made will fully justify themselves, subject to the technology of work and the correct choice of materials.
Monolithic floor technology
When planning construction, it must be borne in mind that a monolithic floor slab is simultaneously the ceiling of one floor and the floor of another. Based on this, this structure must have a sufficient margin of strength and rigidity so as not to bend under its own weight and the mass of the property and people on top.
There are such rules for arranging a monolithic floor:
- Mandatory reinforcement. The metal frame binds the concrete, makes it resistant to bending loads, and prevents the formation of cracks.
- Only the best quality materials are used. In such matters, savings are unacceptable, since it will be impossible to correct mistakes after the end of construction.
- The slab must be supported on the external load-bearing walls of the building. At the same time, an armored belt is pre-installed on them, which prevents the destruction of the material under it and the deviation of the walls from the vertical.
- Horizontal alignment before pouring concrete. The permissible deviations are 2-3 mm.
The general structure of the slab is a layer of concrete with a steel frame inside. The upper and lower edges of the frame should be no closer than 25 mm from the corresponding overlap planes.
Monolithic slab thickness
A too strong structure will create critical pressure on the walls and foundation, and this will require additional costs to strengthen them. A thin slab can bend and crack under vertical loads.
The slab thickness depends on the following criteria:
- Wall material. If the brick can withstand any weight, then the aerated concrete may crack, and the armopoyas will not help either.
- Room configuration. The norm is considered to be the thickness of a monolithic floor slab at the rate of 4 cm of thickness per 1 running meter. the length of the room. For a house where the largest room has a side of 8 m, an overlap with a thickness of 30 cm is made. If this figure is 5-6 m, 25 cm of reinforced concrete is enough.
The slab weight can be reduced by reducing the specific gravity of concrete from the standard 2500 kg / m³ to 1500-1800 kg / m³ by adding a light filler. These are expanded clay, wood chips, polyurethane foam and plastic balls.
Positive design characteristics
Compared to prefabricated structures made of wood, metal and reinforced concrete, a monolithic floor has a number of significant advantages:
- there is no need to involve cargo and lifting equipment for the delivery and installation of structural elements;
- no seams and cracks, perfect horizontal surface;
- the minimum amount of finishing work on the finished structure;
- uniformity of the slab, uniformity of deformation over the entire area;
- strength, high bearing capacity;
- complete tightness, no risk of leaks;
- the ability to do it yourself without buying professional tools and equipment.
Even with such an impressive list of the advantages of a monolithic structure, a condition for achieving a high-quality result is adherence to the sequence of work and the timing required for the maturation of concrete.
Reinforcement laying and calculation
The strength and rigidity of the finished slab depends on the quality of the reinforcement. However, here you need to not overdo it so that the structure does not turn out to be overly heavy. The correct approach involves the manufacture of a three-dimensional frame, consisting of two grids rigidly attached to each other with a cell of 20 cm. First, a diagram is made, and then, based on it, the need for reinforcement is calculated. Calculating the right amount of material is quite simple. You need to multiply the perimeter of the room in meters by 5 and add another 20% of its value to the product for making frames. For a room of 4 × 5 m, 108 m of reinforcement will be required ((4 + 4 + 5 + 5) × 5 +18)).
The skeleton can be assembled using the following procedure:
- Directly on site. First, longitudinal rods are laid out, then transverse ones, then the elements are bonded with annealed wire. After installing the one-piece frames, the process is repeated with the top layer.
- In parts. In a convenient place, blocks with sides up to 200 cm are assembled, then transferred to the formwork and already there they are connected with other fragments. This does not affect the strength if an overlap of at least 50 cm is made.
The assembled frame must be rigidly fixed in the formwork to prevent its displacement when pouring concrete. For this, plastic spacers are inserted every 50 cm between the mold and the frame. If you use welding, then only for steel grade "C", which does not lose strength after heating.
Pouring a monolithic floor
Monolithic slab formwork consists of vertical support columns, beams, flat base and side rails. Fastening of the side walls is carried out using through steel ties.
To prevent the solution from leaking out, the gaps between the shields are sealed with putty, and a polyethylene film is laid on top.
The solution must be poured continuously, with minimal intervals, so that it does not have time to grab. This will avoid delamination and cracks. On the second day, the slab must be moistened, and further construction can be carried out only after 28 days.
Calculation and manufacture of flooring for corrugated board
The technology of pouring a monolith is practically no different from a similar process using boards, laminated plywood and chipboard. Since the ceiling will be ribbed, it will have to be covered with a stretch or suspension system. To create the formwork, you will need a wall profiled sheet, which is characterized by increased strength.
The panels can be stacked end-to-end or overlapped. It depends on the configuration of the support system. To prevent the sheets from moving, they need to be screwed to the beams. The cellophane laid on top of the formwork will protect the corrugated board from contamination and prevent leaks.
The formwork manufacturing procedure, reinforcement and pouring are carried out according to the standard method.
