The thickness of the screed under the warm floor depends on many factors, but it should be the same over the entire surface. The arrangement of the water floor is carried out in several stages, where the organization of hydro and thermal insulation is mandatory, laying reinforced mesh, pipes and screed device. The last stage of work requires special responsibility from repairmen and adherence to technology, because the protection of the heating system and the preparedness of the surface for laying the final, decorative coating depend on this. It is the appropriate thickness of the screed that ensures strength and uniform heating of the floor.
General principles for calculating the size of the concrete screed layer
The cement screed, which is located above the warm water floor, is not just a layer of poured mortar. It provides the necessary pressure to the pipes for crimping and their reliable protection against mechanical damage, and also contributes to uniform heating of the floor. In the process of work, it is very important to correctly calculate the thickness of the screed for the optimal functioning of the entire heating system. What should be taken into account in the calculation process?
- The thickness of the screed is determined not by the wishes of the owners of the apartment, but by many other factors - the structural features of the building. This takes into account the thermal power of the surface, the properties of the floor, the type of facing material, etc.
- The screed allows heat to be evenly distributed over the floor surface; too thick a layer provides a large heat capacity, a thin layer heats up quickly. But in the first case, the surface warms up for a long time, and temperature control is difficult. A thin layer guarantees a quick heating of the floor, but it is too prone to cracking and cannot provide an even heat supply.
- The organization of this heating system involves covering all heating elements with a solution. The optimal total thickness is plus or minus 65 mm.
How to calculate the thickness of the screed?
The thickness of the screed over the underfloor heating is carried out in such a way that there is a solution layer of at least one centimeter above the pipeline. This is necessary to prevent cracking of the concrete. The calculation is based on the diameter of the pipes of the heating system. So, when using standard pipes with a diameter of 20 mm, the optimal thickness will be 40 mm, where 20 mm is placed on the pipeline, and the remaining 20 mm above it. The correct calculation provides not only uniform heating of the surface with heat accumulation in the base, but also eliminates the strong deformation of the outer layer from uneven thermal expansion.
When using pipes of this size, it is possible to allow an increase in the thickness of the finishing screed by another 10 -20 mm. That is, its size should not exceed 60 mm, otherwise the organization of the underfloor heating system will be impractical in terms of efficiency. A lot of energy will be spent on warming up a thick concrete layer.
The thickness of the screed also depends on the purpose of the room. The minimum consumption of mortar is required for residential premises, and in shopping pavilions, warehouses or car centers, the thickness of the concrete surface above the pipes should be greater. This is due to the excessive load on the floor surface, as well as the fact that public spaces do not need the same heat transfer as in the case of residential buildings. The thickest screed - more than 30 mm above the pipeline is used in aircraft hangars.
What else should be considered when calculating the thickness of the concrete screed?
A screed on a warm water floor can be reinforced if you plan to place large items in the room.For example, the installation of a piano will require the placement of a metal mesh in the top layer of the screed, which can be located pointwise or across the entire surface. Special solid additives in the form of fractions make it possible to increase the strength of the screed, as well as mixtures for self-levelling floors, which makes it possible to slightly reduce its thickness. Therefore, with the standard calculation of the screed layer above the pipes in the amount of 40 - 50 mm, using the above tools, you can leave its thickness from 20 - 25 mm. You should not save on materials for organizing the final layer of a warm floor - later this will negatively affect its strength and heat transfer of the heating system.
To calculate the volume of the screed, you should calculate its thickness and multiply the resulting figure by the area of \u200b\u200bthe room. Fractional particles are considered to be polypropylene shavings and fibers, which contribute to good floor strength and are often used by craftsmen in the process of organizing underfloor heating.
On a note
- Before proceeding with the pouring of concrete, it is necessary to check the performance of the underfloor heating system and its hydraulic density.
- To avoid unnecessary heat loss, do not ignore the laying of heat-reflecting material under the piping system.
- The efficiency and economy of all heating is affected not only by the thickness of the screed, but also by the quality of the materials used. This is especially true for cement, which tends to cake. Approach the choice of materials carefully and purchase cement only immediately before starting work.
After filling the solution, it should be given a sufficiently long time to dry. A thick screed under a water floor dries on average up to one and a half months, and only after it is completely dry can you start laying flooring. To prevent cracking of the concrete layer, it is necessary to moisten it with water 2-3 times a day for ten days. Sufficient moisture during drying will prevent cracking of the concrete and allow the cement to gain the necessary strength.
