2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54
- Device diagram
- Ground options
- Reinforcement and beacons
- Installation of screed on the ground
When installing the main floor in private buildings, in warehouses or in sales areas, a rough floor screed is popular. It can be arranged regardless of what kind of soil is under it, as well as the possibility of being in the groundwater zone. All requirements for the use of materials and surface preparation are prescribed in the design and estimate documentation. When performing work on your own, you must adhere to technology in order to get an excellent result.
If we take into account the location of the rough floor screed to factors such as soil level, foundation, location of the groundwater zone, then certain options can be distinguished that allow the installation of the screed:
- Adjacent to the foundation (strip), below ground level. Suitable if there are basements.
- At ground level, adjacent to the side wall of the foundation. In addition to private households, such a scheme is used to a greater extent in industry when arranging storage facilities and working areas.
Above the foundation tape. It is used with high soil moisture, in places where frequent floods are possible.
There is no way to choose a universal way to arrange a rough screed. The main condition here is that you should first plan the location of the door frame, and only then proceed with the installation. The level of the threshold must match the level of the poured screed (topcoat).
Not a single builder has the classic option of pouring a rough floor screed, but to approach the choice depending on specific conditions. The optimum is soil, which is carefully rammed, a layer of sand, a layer of crushed stone (sand and crushed stone should have different heights). Subsequently, a polyethylene film is laid and the screed is installed in a rough form. Reinforcement is not always used and is also based on individual performance.
The diagram can be simplified if the groundwater is located below two meters from the earth's surface. The rough screed can even be poured directly onto the ground. Concrete is not afraid of moisture, therefore, the film in this case contributes to the retention of cement milk. In this case, the strength will increase markedly.
A very important and initial step is to carry out research activities on the base, where the subfloor will be poured. It should not have brightly protruding elements or depressions. You have to deal with them. After that, marking work is carried out when optical or laser levels are used.
In this case, a zero mark is set, the level of the floor surface is located, the relief is determined. If you do without compaction of the soil, then in the future you may encounter subsidence, which will affect the condition of the screed. Ramming also allows you to avoid the appearance of cracks on the surface of the subfloor, cracking it with the ensuing consequences.
The completed screed is the basis for the subsequent laying of flooring of any kind. But at the same time it serves to level the surface, create a hard layer. If desired, it can mask any type of communications in the building.
You can tamp the soil on your own. But this is very problematic for achieving a positive result and is energy-intensive. The best case is the use of special equipment (ramming machines).
Then, river sand of a certain thickness is poured onto the soil layer. The selected layer differs from the one that is poured onto the surface. The latter should be about a quarter larger.
This is all done for the reason that river sand is moistened and compacted by special machines (roller, vibratory rammers). As for the special equipment, everything will depend on financial capabilities. With their help, you can perform any amount of work with a high level of quality, but even the cost of rent is quite high.
To compact the sand base, an additional layer of expanded clay or gravel can be poured. Everything will depend on the final layer of the rough floor screed, base errors.
When pouring the subfloor in the house, it is not enough to arrange only the base and proceed with the installation. In addition to this, other very important layers should be organized. Among them, one of the most important is the waterproofing layer.
Laying waterproofing on the floor serves to protect against moisture penetration from the concrete screed into the base, as well as the reverse process - drawing moisture from the existing soil. As a material for the device of this layer, polymer membranes or bituminous materials in rolls are used. Another alternative to the above materials is a thick polyethylene film. All this can be purchased without any problems at any hardware store.
Waterproofing can only be installed on a solid and level base. This will preserve the service life. Therefore, it is necessary to qualitatively compact the soil and layers of the fill.
The selected material should be located on the base with sheets with an overlap of 10-15 cm. The sheets are joined together using construction tape. We must not forget about the establishment of a layer of waterproofing on the wall to a height of 15-20 cm. We must not be afraid to make a larger flooring, since later the surplus is removed without problems. Waterproofing the concrete floor is mandatory to achieve the desired result.
Reinforcement and beacons
When the waterproofing was handled without problems, you can think about high-quality reinforcement of the future rough screed. This will increase the strength characteristics of the floor. As a material, a reinforcing mesh is usually chosen, having cells with a pitch of 50 * 50 or 100 * 100 mm. The thickness of the rods in the mesh is within 5 mm. All the necessary reinforcement parameters for a rough screed can be found in the store, where everything is implemented with a complete set for work. An alternative to steel mesh is polymer, which has a significantly lower weight, which is very important when installing the screed on floor slabs. Here you will need to comply with the requirements for the maximum weight of the finished structure.
We must not forget that the metal mesh should not be laid directly on the base, since in this case it will not bring the desired result. Usually it is located on special elements in the form of a poured solution or concrete fragments, approximately in the middle of the thickness of the future rough screed.
Technology does not stand still. Pouring the rough screed can be done using fiberglass together with steel mesh. Fiber allows you to significantly reduce the total weight of the solution used in the work, and also gives it certain additional properties and qualities, which include high strength and excellent plasticity. All this helps to get rid of the possible appearance of cracks on the surface, shrinkage after complete drying. In addition, the cost of using such a material in a solution will be slightly lower than a steel mesh, when calculated for each square meter of the room area. The final choice will depend on the artist.
The future rough screed will turn out to be smoother and more practical if set correctly at the level of the beacons. They can be performed in various ways and options. The most common special profiles are called beacon profiles. They are fixed to the base on cement protruding elements from the ready-made mortar.
Installation of screed on the ground
To install the screed, you can independently prepare a solution, observing the proportions of all components used. If there is no time and desire to spend energy on this event, then the ready-made mixture can be ordered from construction companies in the required volume. When there is a financial limitation, you should make calculations in each individual case and decide on a specific option.
The density of the mixture for the rough concrete screed should be medium. This will allow it to spill over the surface on its own and requires little or no leveling effort. In this case, you can even do without beacons.
When the sub-floor is filled with concrete, you can start caring for it. Within a few days, the surface needs to be moistened for high-quality drying and obtaining strength characteristics. In the next two weeks, concrete will be able to gain about 50% of the strength of the maximum. This allows all types of construction work to continue. Floor screed on the ground does not have any particular difficulties. The main thing is to follow the technology of installing the screed and perform all stages in sequence.
When performing work, the main thing is to understand how to properly fill the subfloor. There are subtleties and nuances here. It will not be superfluous to answer some interesting questions that will avoid difficulties in the process.
Is it possible to replace crushed stone with broken brick with other construction waste?
Answer: In no case is it possible. Crushed stone, unlike broken brick, is able to protect the rough screed from excess water. Expanded clay is not suitable for backfilling in this case, since it will begin to swell from moisture. Even if protection from moisture is not required, then broken brick is difficult to ram due to the different fraction of elements.
Is it possible not to reinforce the rough screed?
Answer: Mandatory reinforcement is provided for the finishing layer of the concrete screed. Therefore, this layer can be dispensed with under certain conditions.
Is there a sufficient waterproofing layer under the rough screed?
Answer: Under the rough screed, a polyethylene film or other material only helps to retain milk in order to obtain better mortar strength during the drying process. A waterproofing layer is required even after installation, before laying the finishing layer.
What is the optimal placement of the mesh reinforcement?
Answer: The approximate distance from the base of the location of the metal mesh in the thickness of the concrete screed is 30 mm. But you should focus on the total thickness of the fill and place a layer of reinforcement in its central part.
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