DIY electric underfloor heating under the tiles

Recommendation points

• Power selection
• Section layout
• Required tools and materials
• Mounting
• Electrical connection

When installing an electric underfloor heating under a tile with your own hands, the main thing is to follow the order of work, and pay attention to the important points of installation. Connecting to electricity underfloor heating will not cause you any difficulty. We will also give you some professional advice.

Power selection

Calculation of the power of underfloor heating is not difficult, but here we will solve this issue in a different way. We will consider not the power as such, but the required length of the electric floor cable. Let’s take it for granted that the cable laying step is fifteen centimeters. This is the most optimal value. We will also assume that it takes about twenty-five centimeters of cable for one loop when laying. Now, knowing the dimensions of the area on which we will lay the warm floor (width and length), we can calculate the number of cable branches, the number of turns and its entire length. Let’s not forget to take into account part of the cable to bring it out from under the future screed to the wall, to connect to the thermostat. To correctly determine the area of ​​laying underfloor heating, consider some rules for the location of the cable in the room.

Section layout

Since the conversation is about underfloor heating under tiles, then most often it is a corridor, a bathroom, a kitchen. For example, consider the installation of electric underfloor heating in a bathroom. Styling in other cases will differ only in nuances. The bathroom can be equipped with plumbing fixtures (bath, washstand, etc.), washing machine, bedside table. The floor area occupied by these items should be excluded from the floor heating installation area. We will also retreat five centimeters from the walls and thresholds. It’s okay if the area is not rectangular, a flexible cable of a warm electric floor allows you to lay on an area of ​​any configuration.

1 – clutch; 2 – thermostat; 3 – corrugated tube; 4 – temperature sensor; 5 – end sleeve; 6 – heating cable; 7 – mounting tape

When performing work in the bathroom, it is better to bring the ends of the wires, not the heating cable itself, namely the connecting wires of the warm floor, to the corridor for the convenience of using the thermostat and preventing moisture from entering it.

Required tools and materials

1. Heating section of electric underfloor heating (a piece of wire with soldered ends).
2. Metal perforated strip with a notch for fastening the cable.
3. Corrugated tube (for removing wires from under the tie to the thermostat and the location of the temperature sensor).
4. Room thermostat (it is chosen depending on the required complexity of heating control). You can choose the simplest and cheapest available.
5. Thermal insulation. Usually, foil-clad foamed polyethylene sheets of various manufacturers (Folgoizol, Ekofol, etc.).
6. Adhesive tape for bonding thermal insulation joints.
7. A number of dowel-nails and a punch for attaching the mounting tape to the rough screed.
8. Hammer, screwdriver, knife.

Mounting

Let’s look at the base first. Better if it is a rough screed. It should be relatively flat, free of deep potholes, dry and clean. The holes should be sealed with cement mortar and allowed to dry, and the protrusions should be knocked down. Next, we lay the insulation. It is usually laid over the entire area of ​​the room where the tiles will be laid, from wall to wall. The joints of the insulation sheets are glued with tape, preferably foil.

The laying of the metal fastening tape is carried out already on the area where the warm floor is laid, only where the heating cable will lie. The step of laying the tape is selected based on its quantity complete with a warm floor, so that the cable is fixed throughout the entire laying area. Attach the tape to a few dowel nails, not too often.

Let’s drill a hole in the wall, at floor level, to lead the ends of the connecting wires to the outer surface of the bathroom wall. We pass the corrugated tube into the hole. Its end is inserted into the future screed at a distance of about half a meter from the wall. We will carry out a section of the groove along the outer surface of the wall, where we will hide the end of the tube. The strobe is made from the hole to the installation site of the thermostat. Subsequently, the groove with a corrugated pipe is sealed with gypsum putty or cement mortar.

The heating cable is laid starting from the end of the corrugated tube passed through the hole in the wall. The end sleeve of the heating cable (soldered end with connecting wires) must be located at the pipe cut. When laying, we observe a step of fifteen centimeters, make sure that the branches of the cable lie flat, there are no kinks when turning the cable. Be careful not to damage the cable. During installation, the cable should be fixed with special hooks on the metal tape. Straighten the cable, but do not pull it too tight.

It should be noted that there are cable versions on which the connecting wires exit from both end sleeves. Then the laying should be carried out in such a way that both end sleeves are at the end of the corrugated tube..

We pass the ends of the connecting wires into the corrugated tube so that they come out from its other end, behind the wall. From the outside, we lower the temperature sensor into the corrugated tube, to the end of the corrugated tube, but so that it remains inside it. We wrap the edge of the tube with electrical tape so that the solution does not get into it.

After connecting the thermostat and briefly testing the operation of the entire electric floor, you can perform the screed. The screed should be guided along the level guides. For the strength of the screed, use available mesh reinforcement, or better, use special mixtures for warm floors. The screed thickness is five centimeters. After the screed has dried laying the tiles.

Electrical connection

Having decided on the place of installation of the thermostat, we fix it on the wall. Thermostats can be both external and built-in. In the second case, it will be necessary to install a socket box (installation box), and install a thermostat in it.

The wire from the electrical network of the house (from the nearest junction box) is connected to the thermostat contacts L and N (line and zero). The ends of the wire connected to the heating conductors of the underfloor heating cable (they are usually white) are connected to the contacts on the thermostat 3 and 4. The wires connected to the protective shield of the heating section cable (they are often yellow-green) must be connected to the grounding circuit of the home electrical network … When performing these works, do not forget to turn off the electricity.