2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54
- Main classification
- Dependence of thickness on the composition of the constricting layer
- Other features of the selection of thickness
- Calculation of basic parameters
One of the simplest and most effective ways to level the floor surface is a screed. At the same time, a strong and resistant to various types of external influences, the tightening layer also provides protection for the underfloor heating system (cable or water). It also allows you to further improve the sound and heat insulation in the room. Before creating such a layer, you must first decide on its material, and then on the thickness of the floor screed, which is chosen depending on a number of factors.
There is no exact method for determining what thickness of the screed should be in an apartment, private house or utility room. Moreover, this parameter depends on different conditions:
- for the first floors - from the ground on which the building is installed, or from the presence of a basement;
- for rooms located above - from the type of interfloor floors and the need for sound insulation;
- on the degree of unevenness of the floor;
- from the purpose of the premises;
- from the material from which the screed is made, and its type (dry, semi-dry or wet).
To level the floors in an apartment with different level differences, you can combine a cement and self-leveling floor, this will help to significantly reduce material consumption.
By the height of the constricting layer, it is divided into three groups - minimum, average and maximum.
The most popular options are those that provide material savings and increased strength. In this case, the minimum floor screed height is 20 mm. And for its filling, only waterproofing and a special material are required, which is a self-leveling mixture (gypsum or cement-sand). Lighthouses and reinforcement are not suitable for such a tension layer.
As a rule, the minimum floor screed thickness is taken for flooring with small differences using self-leveling floors. The minimum thickness of the self-leveling screed is 5 mm, although there are mixtures that allow you to create a layer of 1 mm.
To create a middle layer from 10-70, concrete pouring or the increasingly popular semi-dry screed is already used. T-shaped beacons are usually used for alignment, although wooden slats and even metal pipes are also suitable. The value of such a floor screed height in an apartment is within the range of 5–70 mm. The guides are placed at a distance of 1000-1500 mm, depending on the length of the rule. Before pouring the cement screed, first arrange a waterproofing layer, then, if necessary, lay a reinforcing material (mesh), and only then - a leveling floor screed, the thickness of which, together with the reinforcement, should not be less than 4 cm. Due to the mesh and the relatively low height, it should be used concrete with the addition of fine crushed stone fractions.
The approximate thickness of the maximum floor screed is 100–170 mm. It is irrational to make the tightening layer thicker than 17 cm - first of all, because of the high cost, and secondly, because of a noticeable decrease in the height of the room. As a rule, such a thickness of the screed in an apartment is needed only when preparing the foundation, which is also the floor, as well as for rooms with high loads. For example, for garages and gas stations. And the maximum thickness of the screed in an apartment rarely exceeds 50–120 mm. A good and inexpensive way to level the floor is with expanded clay screed.
Dependence of thickness on the composition of the constricting layer
The most popular material for the screed layer is cement-sand mixtures. When using them, the minimum thickness of a semi-dry screed starts from 30 mm. It is this value of the parameter that allows you to hide even large enough irregularities and avoid cracking. As a rule, pouring a floor screed, the thickness of which is not much more than the minimum, is made of sand and cement in a ratio of 3 to 1. If necessary, to compensate for significant differences, use a backfill. And, if the difference in surface levels in different rooms is large enough, in addition to cement, expanded clay concrete is used, increasing the thickness to 80–150 mm, but slightly increasing the weight of the structure.
If gypsum mortars are used for leveling, the layer height is usually in the range of 2-10 cm. Moreover, the minimum floor screed does not provide for reinforcement. Among the advantages of the gypsum layer are fast drying and relatively low shrinkage. The disadvantages include low moisture resistance, due to which the material cannot be used as a base for tiles.
When using the dry method of leveling the floor, the thickness depends on the number and size of unevenness. As a rule, in this case, the minimum thickness when laying GVL sheets in an apartment starts from 30mm. If you make this layer smaller, the GVL sheets laid on top can move, making the structure fragile and capable of collapsing long before the end of its operational life.
Other features of the selection of thickness
The size of the minimum screed layer in an apartment is almost always determined individually. In this case, the following nuances are taken into account:
- laying over insulation on a cable heating system. In this case, make a leveling floor screed with a thickness of at least 40 mm;
- lack of insulation and sound insulation for those cases when the installation of the tension layer is carried out immediately on top of concrete slabs. The thickness of such a screed starts at 2 cm;
- availability of water floor heating, made with pipes with a diameter of 1/2 "to 1". Taking into account the parameters of the pipeline, the minimum floor screed in the apartment will be 25–30 mm.
The heating system can significantly affect the construction of the tightening layer. Due to the fact that the "warm floor" has a high temperature, the screed will expand. This means that at the joints with the walls, it must be pasted over with special tapes that prevent deformation during expansion. At the same time, the maximum thickness of the floor screed in an apartment in the presence of water heating under the floor is not recommended. The best option is from 40 to 60 mm, while an increase in the layer height may require high energy costs to heat the room.
Calculation of basic parameters
To determine what the floor screed should be, and, therefore, what the material consumption and theoretical properties of the screed will be, it is necessary to take measurements. The procedure is as follows:
- The existing coating is completely dismantled (disassembled or removed using a hammer drill and hand tools) to the concrete slab itself;
- Marks are placed on the walls - in one completely horizontal plane and at a distance of about one and a half meters from each other. For this, a level is used (standard water or laser);
- The marks are connected by a line and distances from several points are measured to the floor level. The thickness of the screed is determined by the minimum value and its difference from the maximum difference. If there is no hot water heating in the room, a point can be taken as the upper level, the vertical distance from which to the conventional reference plane will be less. In other cases, the layer height is increased to the required value;
- The amount of the mixture that will be required to create the tightening layer is calculated. To do this, use the value of the minimum thickness of a semi-dry floor screed, which is suitable for specific conditions. By the height of the layer and the area of the room, the total weight of the structure and other parameters are determined - the cost, the amount of cement and sand (the main materials from which the screed is made).
In order to simplify the calculations, you can use a special online calculator for calculating materials. At the same time, such indicators as the area, and the thickness, which should be the floor screed in apartments, are entered into the form. You should also choose the grade of the screed (usually M200 or M300) and cement (M300 - M500). Sometimes in such calculators even the cost of materials is indicated, which makes it possible to simplify the calculation of the estimate.
|Product||Sand concrete M-300 TsSM Sand concrete M-300 RUSEAN Sand concrete M-300 RUSEAN LUIX coarse fraction RUSEAN M-400 dry concrete Dry mix NTs waterproofing cement White masonry mortar OSNOVIT BRIKFORM MS11 (T-111) Masonry mortar OSNOVIT BRICFORM MS11 (T-111) Masonry mortar OSNOVIT BRIKFORM MS11 М-300 Etalon Sand concrete М-300 Stone flower Sand concrete М-300 VILISS Dry mix М-150 PERFEKTA / PERFEKTA Universal Dry mix М-150 PERFEKTA / PERFECT Plaster Dry mix М-200 PERFEKTA / PERFECT Luxe Mounting (sand-concrete) Sand-concrete 300|
|Surface area m 2|
|Layer thickness, mm.|
Calculators from wpcalc.com
The final stage of the calculation is the device of the screed itself. For thicknesses from 20 to 30 mm, a self-leveling layer is used for which guides are not needed. When installing a screed with a higher height, a semi-dry or dry technique with beacons can be used. In the first case, the material is poured in strips up to 1 meter wide. In the second, a special mixture is laid on top of the backfill (expanded clay, perlite, vermiculite) - for example, Knauf - and gypsum fiber sheets are used as the topmost layer.
When determining the thickness of the floor screed in an apartment, one should be guided not only by the need to level the floor. A rational approach to calculating the height of the tightening layer will save both material and time for its installation. In addition, the minimum thickness of the floor screed in the apartment, permissible for specific conditions, will provide a relatively small decrease in the height of the room.
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