There are several varieties of underfloor heating, and accordingly, each of the possible options for building heating has its own characteristics. Their ignorance in the process of performing work can have sad consequences. Therefore, in order to avoid such troubles, it is best to first familiarize yourself with what constitutes the installation of a warm floor and what features of its installation must be taken into account in the process of work.
About types of warm floors
Before getting acquainted with various underfloor heating systems, it should be noted that only electric heating will be available for a resident of a multi-storey city building. Therefore, it is the option of installing a warm floor of this type and its inherent features will be discussed below. Without going into the design of the heating elements themselves, which are the basis of the entire heating system, it is necessary to note the following types of underfloor heating:
- cable;
- using heating mats;
- infrared or film.
Installation of a film underfloor heating is simple and straightforward, although it also has its own subtleties. However, for the purpose of a more detailed acquaintance with warm floors, let us dwell on the nuances inherent in the first two types.
Looking ahead a little, it is worth noting the main difficulty of installing a warm floor using a cable. This is the creation of an additional screed on the floor surface, which raises the level of the floor by up to eight centimeters. In many cases, this is unacceptable, but there is another approach that allows you to install a warm floor without such difficulties.
General procedure for laying floors
It should be noted right away that the described procedure primarily affects cable floors, but many of these steps must be taken into account when installing underfloor heating mats.
floor heating planning
This stage is one of the main ones that determine the successful operation and efficiency of the heating system. Here it is required to calculate the power of the entire system, the step and place, the configuration of the location of the heating elements. In this case, it is necessary to take into account only the area free from household appliances, plumbing, furniture. It is on it that you can lay the heating elements, performing the installation of a warm floor. How it should look like is shown in the figure below:
The choice of the power of the warm floor
Knowing the area on which the installation of the underfloor heating system that you have chosen will be carried out determines its capacity. This task is not at all simple, the power of the heating system depends on the type of room that needs to be heated. So, for a heating cable in dry rooms, a power of one hundred to one hundred and twenty watts per square meter is enough; in wet rooms, a power of up to one hundred and fifty watts per square meter is required. Moreover, these figures are valid in the case when floor heating is carried out in addition to the existing central heating system.
If, when installing a warm floor, you expect to use it as the main heating system, then the power of the heating cable should be higher, at the level of one hundred and seventy watts per square meter.
Now we are talking about the heating cable. Its choice is made based on the requirements of the required power, which can be obtained as the product of the free area and the power of the cable required to heat the premises of the desired category and type of heating (main or auxiliary). The power of a warm floor using heating mats is determined based on the area on which the floor heating will be installed. Each size of heated area requires its own set of heating mats.
How to position the heating elements
It has already been mentioned that when installing a warm floor in a house, it is necessary to focus on an area free from foreign objects. However, this is not the only requirement, especially when using a heating cable.
Installation of the underfloor heating cable depends on the type of cable itself. It comes in single and double strands. Without touching on the advantages and disadvantages of each of them, without delving into the constructive differences between these types, it is enough to say that each of them requires its own. To understand the differences, just look at the figure below:
It immediately becomes clear from it that when using a single-core cable, its opposite end must return to the starting point where the installation began. Whereas when using a two-wire cable, this is not required.
In addition, when planning the placement of the cable, it is necessary to take into account, at a minimum, other factors such as the distance from it to walls or interior items and the step with which the cable is laid. The laying step is calculated according to a special formula, the distance from the wall is five to ten centimeters, and the cable bend must have a radius of at least five centimeters.
Surface preparation for installation
After completing all the planning and calculation work, the installation technology itself, no matter what type of warm floor you have to install, will not pose significant difficulties. Initially, you need to install a place for the thermostat. It should be located in a convenient place, the height above the floor should be at least thirty centimeters. From this point, a strobe breaks through, into which the sensor connection circuits and cable power wires will be laid.
The floor is carefully swept and leveled if necessary. To do this, if necessary, you can perform a cement screed. Its thickness must be at least three centimeters, otherwise it may crack during operation. Before applying the screed, the floor must be primed.
thermal insulation
It is required to reduce heat loss and increase the efficiency of the underfloor heating. In principle, thermal insulation can be carried out in some other way than the one described, or someone can refuse it altogether. In the latter case, one must be prepared to put up with significant, up to 30%, heat losses and insufficient efficiency of the underfloor heating. The proposed method, how to mount a warm floor, can be considered a classic option.
Thermal insulation must be horizontal and vertical. The latter is done along the walls, starts at their base and reaches a height of fifteen to twenty centimeters. For this, polystyrene up to one centimeter thick can be used. The task of such thermal insulation of walls is to reduce heat loss through them.
Losses through the floor are reduced by horizontal thermal insulation, which can be based on polypropylene, expanded polystyrene or other similar materials with a thickness of at least two centimeters.
The material used must be durable and able to withstand mechanical stress, as well as be heat resistant. If the underfloor heating is intended to be used in a humid environment, for example, in a bathroom, then additional waterproofing can be made.
After laying the thermal insulation, a cement screed is made on top of it. In cases where it is impossible to make a screed for some reason, a fine metal mesh is laid instead, which is then poured along with the main, finishing, screed.
Cabling
After the screed has hardened over the thermal insulation, you can continue to work on creating a warm floor. First, a foil is placed over the base, which will evenly distribute heat from the heating element. Mounting tape is located on top of it, for a warm floor - cable, it serves to fasten the latter. What it is and how the cable is fastened can be seen in the photo below:
The fastening of such a tape to the floor is carried out with self-tapping screws or in any other way. The tape is located perpendicular to the direction of the cable in increments of fifty centimeters. Cable laying is carried out in accordance with a previously drawn up plan. One end of the cable (two-core), the so-called cold one, is placed in a corrugated tube and located at the thermostat in a pre-prepared strobe. When laying the cable, it should not touch or intersect with other sections, the laying step should be constant.
If the cable is single-core, then its other end must return to the thermostat. The termination on a two-core cable must be located in such a way that it, like the entire cable, is filled with a tie.
The temperature sensor is located in the corrugated tube directly between the cable spirals and leads to the thermostat. Attaching the cable to the mounting tape is carried out as shown above. The photo below shows what a floor heating installation ready for pouring looks like; in the screed, the layer of which is three to five centimeters, the temperature sensor and the end sleeve of the two-core cable must be filled. After the screed has dried, the underfloor heating is ready for use.
On top of the floor after pouring the screed, it remains to complete the finish coating, and after that the work on creating a warm floor can be considered completed.
About underfloor heating
A common practice is to install a warm floor under the tiles, i.e. tile or porcelain stoneware will act as a finishing coating. These materials themselves are cold, and their heating during operation will give them additional positive properties.
