Technologies for the construction of buildings from reinforced concrete have become widespread due to the reduction in the cost of construction. One of the important elements during pouring is the formwork of floors. She takes the load from the concrete mixture until it completely hardens.
Advantages of monolithic overlap
When choosing materials for the construction of the building, it is necessary to take into account many factors that will affect the timing of the construction and the final cost of the building. Monolithic overlap has the following advantages:
- the ability to do it yourself;
- no need to use lifting equipment;
- reduction in construction costs;
- strength and reliability;
- the possibility of overlapping premises of complex shape (rounding, bay windows).
To fill the concrete floor, you need to pay attention to three of its components:
- concrete mix (not lower than B25);
- reinforcement (depending on span and loads);
- formwork.
Formwork requirements for floors
Monolithic overlap is a responsible design, therefore rather strict requirements are imposed on its base:
- high strength and ability to withstand dynamic loads;
- installation in a strictly horizontal position;
- simplicity of installation and dismantle;
- prevention of deflection of the structure;
- ensuring safe working conditions during construction;
- ensuring the durability of the structure.
Compliance with all these points will allow you to perform competent installation of the floor with your own hands.
Types of construction
The working surface between floors, on which the solution is poured, is performed by two methods:
- removable formwork;
- fixed formwork.
When erecting multi-storey buildings, where costs can easily pay off, it is rational to use special removable shields that are installed using jacks. When building a house with their own hands, such costs will not pay off and will greatly increase the cost of the building. In this case, the installation of formwork for floors made of simpler materials will be the best solution.
Self-pouring involves the use of available materials, which include:
- professional sheet;
- moisture resistant plywood;
- wood.
If you are planning significant loads on the floor from a monolith, it is best to use corrugated board. Wooden formwork and moisture-proof plywood are suitable, for example, for overlapping the upper floor when installing the attic, when the loads on the horizontal structure are small.
Formwork Stands
By design, installation can be of two types:
- using a design on telescopic racks;
- volume racks.
Volumetric elements are used with significant floor heights. For a residential building will be enough telescopic. Such racks consist of three elements:
- univilka;
- vertical support;
- tripod.
The upper part is a univilka, used to fasten the work surface. As the second name use the "support fork". It is made of a 5 mm thick metal plate and four square tubes welded at the corners. It is designed to fix the beams.
A tripod or skirt ensures stability of the rack, holds it in a horizontal position. She also perceives part of the dynamic loads when filling the slab.
To maintain floors less than 30 cm thick (large thickness for residential buildings is irrational), it is recommended to purchase standard racks with open or closed thread (marking STO, STZ). Factory-made racks are available in the following sizes:
- 170-310 cm;
- 200-370 cm;
- 240-420 cm;
- 300-450 cm.
For the construction of an individual apartment house with their own hands, most often a size of 170-310 cm is enough. The installation step is taken no more than 150 cm.
In the absence of the possibility of acquiring telescopic elements, the support posts are made of timber or steel pipes. Wooden racks are rationally used when using timber or OSB formwork, and metal racks from profiled sheets.
Installation of flooring according to the profiled sheet
To fill the plate between floors with your own hands on sufficiently large spans, it is best to use a profiled steel sheet. The design will cost more than when using wood, but will provide high reliability. The overlap is made in the following order:
- installation of load-bearing beams (I-beam or channel);
- laying and securing the profiled sheet;
- reinforcement laying;
- concrete laying;
- concrete compaction.
As supporting beams for small spans of floors between floors (4-5 meters), you can use the channel N16 or I-beam N 20. The profiled sheet is laid so that its ribs are perpendicular to the supporting beams. Leaning on all sides on the walls should include at least 100 mm.
The professional sheet according to the standards has the following brands:
- "N" for horizontal structures;
- "C" for vertical structures;
- "NS" is universal.
For floors in the house you can not use the brand "C", this material does not have sufficient strength and will easily bend under the action of the load. Installation of the plate is carried out according to the profiled sheet of brands “N” or “NS”.
The height of the profile depends on the calculated load and the pitch of the structural beams between the floors. DIY installation in an individual house is possible without complex calculations. In most cases, the plate will have enough material grade H60-H75.
The advantages of flooring on corrugated board include:
- high rigidity and structural strength;
- the ability to withstand severe loads, both during the filling of the slab, and during operation;
- monolithic overlapping on a metal base allows to reduce the consumption of concrete and reinforcement;
- the possibility of reducing the mass of the floor due to the use of a ribbed structure;
- reducing the loads on the foundations and reducing their cost.
All these characteristics made it possible to obtain designs of great popularity when building a house with your own hands. The slab between the floors in this case has a high bearing capacity and a long service life.
Monolithic overlap on moisture-proof plywood
At light loads it is extremely disadvantageous to use expensive steel. In this case, pouring concrete with your own hands can be done on plywood sheets. The material must be moisture resistant, otherwise it will be damaged by moisture from the concrete mixture before operation. Installation of the plate assumes the following materials:
- moisture resistant plywood (laminated);
- load-bearing beams made of glued or solid wood;
- support racks.
The use of glued wood allows you to increase the span of the floor. Installation begins with the installation of load-bearing beams, the cross section of which depends on their pitch and load.
For example, for a span of 4 m and a beam pitch of 1 m, a section of 100 per 100 mm with a standard load of 150 kg per square meter will be sufficient. When using glued beams, the calculated cross section will be less.
After installing the beams, the installation of plywood sheets begins. Fastening to the load-bearing beam can be carried out using self-tapping screws or nails. Then, using special plastic clips, the fittings are installed in the design position. And the concrete slab is poured. To increase the waterproofing, a plastic film can be laid between plywood and concrete. If the base for the slab is made of wooden boards, laying a layer of waterproofing between them and the monolith is mandatory.
Before pouring along the perimeter of the walls from the boards, a side is installed. It is selected depending on the thickness of the monolithic plate and should be the same height along the entire length. It is important to carefully control the corner joints.
It's important to know
A monolithic overlap during the construction by yourself requires a sufficiently large knowledge base. Only the right choice and installation of formwork is not able to provide guarantees that in the future there will be no problems with the design.
Proper installation of a concrete slab does not end with its pouring. It is important to provide care during the hardening of the concrete mix. To prevent cracking, the surface of the plate must be moistened periodically. To gain the full strength of concrete between pouring and further work, it is necessary to wait 4 weeks. It is such a period that concrete will need to gain full strength.
If you comply with the technology of doing the work yourself in a private house, you can significantly save on construction without compromising on quality.