Concrete preparation: device of a coupler of a floor and
Concrete preparation is, in fact, a layer of lean concrete, which is arranged under any construction of the cement-sand mixture or from the same concrete.
Now about technology in more detail.
![Photo footing Photo footing](../uploads/img/foto-podbetonki.jpg)
This work is done mainly so that during the pouring of the main amount of the mixture the “cement milk” does not flow out of it, because if this liquid leaves too quickly from the solidifying screed, the floors, for example, will crack very quickly in the future. After all, drying in this case will be too fast, because all the moisture has "gone" into the ground.
In addition, the device of concrete preparation according to the ENR allows more economical, faster and more qualitative to carry out all the rough and marking work before the main casting. After all, you see, it is easier to install guide beacons for the same tie on a flat and hard plane than on loose relief soil. Yes, and the coupler itself is poured in such conditions.
![Strainer «по маякам» Strainer «по маякам»](../uploads/img/styazhka-po-mayakam-600x362.jpg)
Please note that floor scoring is not made when the screed is poured onto floor slabs or other similar surface. In such cases, it turns out that the working plane is sufficiently solid and even enough.
In this article we will look at how the concrete preparation for SNIP is performed step by step and what nuances are important to observe here.
But first, let's figure out where to do this layer.
For which works it is desirable to produce concrete preparation and why
Here, in fact, everything is simple - the data are shown in the table below.
Type of construction | Why do we need the underlying layer |
Strainer
Foundations | As mentioned above, the preparation of lean concrete under a screed of crushed stone or expanded clay is done for better drying of the mixture, as well as for the possibility of installing beacons. After all, it turns out that footing creates a relatively flat plane, and this already makes it possible not to take shrinkage into account and to exclude corrections for the relief when ordering a mortar. A subbetting layer for such structures is simply necessary, because the base is made on open ground, which, as it were, “assumes” too much moisture from the filled mixture. |
Tip: if there is no financial opportunity to make footings when building a foundation or floor, then you can cheat a little and use several other technologies whose price is low. For example, to prevent the leakage of moisture from concrete, you can lay a film or roofing felt on the ground surface.
![An example of pouring the floor on top of the film An example of pouring the floor on top of the film](../uploads/img/primer-zalivki-pola-sverhu-plenki.jpg)
Why is a concrete preparation device required for SNIP, we have already figured out. Now let's look at the specific installation instructions for such a layer.
We do concrete preparation independently
Before proceeding to practical actions, it is worth to highlight one point - we took the simplest concrete structures, which are most often made with our own hands, as good examples.
It is important to remember that everything must be done in the maximum accordance with the rules and GOST.
For example, the permissible deviation of footing across is not more than 10 mm. at two meters. And with a room width of more than 25 meters, the deviation in the horizon can not exceed 50 mm.
In addition, you need to take into account the fact that the lean solution is not poured onto loose soil - the shaky soil is pre-rammed.
If it is necessary to work with a sand base, it is slightly moistened and with the help of a simple tamping device they press crushed stone or gravel into it. The depth of the indentation must be at least 4 cm.
![Трамбовочный инструмент Трамбовочный инструмент](../uploads/img/trambovochnyy-instrument.png)
As for the mixture itself, the footing should consist of concrete on the basis of rubble or expanded clay. What exactly and in what cases to apply - we will describe below.
So, step by step executive scheme of concrete preparation.
For floor screed
The device of the screed is a very important matter, after which all defects, as a rule, crawl out almost immediately. Therefore, if the footing is done poorly, then already after the initial drying of the base layer of the mortar, cracks will appear on the floor surface.
The instruction here will be something like this:
- Need to plan a plane. For this, the ground with shovels is scattered so that the result is a relatively flat working surface.
- The whole plane is rammed.
- On the ground, the usual film is spread so that its edges slightly come up, on the walls.
- Concrete based on crushed stone or expanded clay is kneaded..
![A mixture of expanded clay A mixture of expanded clay](../uploads/img/smes-iz-keramzita.jpg)
Tip: if the work is done in a residential area, then it is better to use expanded clay as a filler, as the floor insulation will be of higher quality. If the floors are poured in the garage or in the warehouse, then it is quite possible to use rubble (especially it is cheaper).
- The mixture with the help of shovels or buckets is pulled apart over the whole area of the room so that the footing layer is as smooth as possible..
Such is the executive scheme for concrete preparation before flooring.
Foundation footing
For this work, concrete is made solely on a gravel base. The fact is that rubble is an inert stone and is absolutely not afraid of water. This means that the preparatory layer will not deteriorate even if the main casting of the foundation does not occur immediately.
This is roughly similar to an operation such as preparing concrete walls for wallpaper - the surface is treated with an acrylic primer, and then the wallpaper can be glued at any time. The quality of the clutch delay will not affect.
Let's go back to the foundations.
The sequence of work here is this:
- At the bottom of the trench or trench poured a layer of sand.
- The sand is thoroughly rammed (do not forget about the pressing of rubble).
- Stripes of ruberoid or film are laid on the working plane.
- Concrete is mixed and the mixture is poured into the trench as evenly as possible. If you fill a slab foundation, then footing for it must be done in the same way as for the screed.
![An example of a solid foundation An example of a solid foundation](../uploads/img/primer-monolitnogo-fundamenta-600x450.jpg)
On this principle, everything is a step-by-step principle of operation and permissible deviations of concrete preparation are considered.
Conclusion
We have figured out in some detail what concrete preparation is, what it is for, and how it is performed. We hope that the information provided and the scheme of work will be useful to you in practice.
We would like to note that you can find out more information on this topic - just watch the video in this article.