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Installation of electric floor heating in the screed

Installation instructions for electric floor heating, the stages of work

In recent years, the underfloor heating system has been widely used to create a comfortable microclimate. as in private. as in apartment buildings. The range of heating materials allows you to pick up the most effective copy to heat your own home. in addition. The popularity of the system is due to the fact. that the installation of electric underfloor heating is possible with your own hands without the involvement of builders or electricians.

In this article we will consider step by step recommendations for installing cable underfloor heating in the screed, which will allow you to easily perform the installation yourself.

You have already purchased a floor heating cable for installation in the screed layer. It is best to install heating cable in a specific sequence, which we will describe in the following instruction.

Choice of a place for installation of thermostat

Before you begin installing the heating cable, you must select and prepare a place for the installation of the thermostat. the floor heating controller and the external floor sensor.

Install the thermostat in a convenient location at a height of 0.4 to 1.7 m from the floor, taking into account the further arrangement of furniture so that it does not block access to the thermostat.

When installing underfloor heating in rooms with high humidity (bathroom, sauna, swimming pool), you must install the temperature controller outside the room.

Drill a hole in the planned location on the wall for mounting a deep (which will facilitate your subsequent connection of the thermoregulator) socket. Then a groove of about 2 cm × 2 cm is furrowed down the wall for laying in it a corrugated tube (or metal-plastic pipe) with a diameter of 16 mm with a temperature sensor and, separately, the cold end of the heating cable.

To the place of the future installation of the thermostat lead the power cable ∼220V, taking into account the power of the underfloor heating and the type of house wiring. The most common use of cable 3h2, 5 (3h1, 5) if the electrical wiring in the house is made by 3-wire scheme or 2×2, 5 (2×1, 5) if the electrical wiring in the house is made by 2-wire scheme without using grounding.

Rules for laying infrared film

Work with the infrared floor requires the patience of the master. This is because there is one pair of wires coming out of each section that is present in the film. If there are many sections, the number of wires also increases. All of these wires need to be connected correctly to the thermostat.

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To simplify the task, the experts advise to mount the unplugging box and make a marking of each wire. Phase-to-phase and neutral-to-zero wires are connected in the box by soldering. Make sure that you end up with two wires. These wires are already connected to the thermostat.

Each heat conducting strip should be insulated on one side, and on the other side the power cable is connected. In order not to make a mistake, you need to lay the sheets parallel to each other.

The installation of the thermo regulator, as well as the groove is carried out in the usual way, which is relevant for other systems. In this case, the temperature sensor should be packed in a corrugated box and fixed to the floor. After that it can already be connected to the thermostat.

The principle of installation of underfloor heating into the screed: steps and recommendations

The minimum thickness of the screed for electric underfloor heating is 4.5-8 cm (with water systems from 10 cm), according to the recommendations of many manufacturers. But they calculate it on the basis of ideal installation conditions.

In reality on the height of the screed layer affects a number of conditions:

  • Subfloor quality. If it is the ground, then the layer height can not be less than 10 cm. If the basis. floor slabs, then the parameter can range from 3 cm to 6-9 cm (the height is determined by the degree of defects of the slab);
  • Type of electrical floor. The cable is laid in a thicker layer of screed. at least 3-4 cm. This ensures the safe operation of the system. Thermo mats and film floor need only light fixation, so the screed under the warm floor of this class should be no more than 3 cm (if the surface is flat, it does not perform at all);
  • Material for filling. Mixes of sand and cement are poured to a thickness of 4 cm or more. Self-leveling levelling. 2-2.5 cm.

Competent laying of a warm floor in a screed requires observance of the basic rule. the basis on which the system is mounted should be 100% even. Otherwise achieve an even heating of the air masses from below the room and prevent overheating, a break in the cable will not work. Therefore, the calculation of screed thickness is carried out taking into account the quality of the substrate surface and materials used. In total, the height of the floor screed for electric flooring can vary from 4.5 to 8 cm for subfloor defects.

Underfloor heating into the screed or under the tiles?

The eternal question of choosing an electric floor in the screed or directly under the tile. In this article we will try to compare these types of floor heating.

Underfloor heating in the screed

Electric floor heating in (under) the screed is installed when:

  • repair at the stage of roughing works
  • it is possible to raise the floor level from 3 cm (without thermal insulation) to 7 cm (with the use of EPPS)
  • The speed of heating is not of prime importance
  • Underfloor heating is the main source of heat.

under-floor heating cables with linear power of 15-20 W/m and a thickness from 4 to 7 mm, depending on the manufacturer, are used in under-floor heating.

Advantages and disadvantages of screed-mounted cable systems

  • it is possible to purchase inexpensive cable (as compared with a thin cable or heating mats);
  • uniform heating of the floor surface (with a correctly calculated step of laying);
  • reliability and fire safety;
  • High thermal efficiency (with properly calculated heating capacity per m2 and use of thermal insulation).
  • any floor heating installation geometry
  • Versatility of use (for any type of coating, any power per m2)

Under tile floor heating

If there is no possibility to raise the floor level or if you plan to heat the tiles to a comfortable temperature, then there are 2 options for underfloor heating: a heating mat or a thin heating cable.

The heating mat is a thin cable laid on a fiberglass mesh with a certain pitch. Because of its thickness 3.5-4 mm for it does not need to raise the floor level and is laid in the tile adhesive layer directly under the tiles. The standard width of the mat is 50 cm. Its main advantages: The mat is a ready-made structure and no special skills are required for its installation. (No need to nail dowels to the screed, no need to play with the cable laying step) The mesh on the mat additionally reinforces the tile adhesive. Heating speed. Once switched on the floor heating will become warm in only 20-30 minutes.

Thin heating cable is the same as a screed heating cable, but with less power per m.п. and diameter 3.5 4 mm.

Advantages and disadvantages of under-tile cable systems

  • laid on a concrete base or over an old ceramic tile
  • You do not need a screed, it raises the level of the floor to cm
  • the heating is faster
  • ease of installation (in the case of heating mats)
  • there is no need to drill screed for mounting tape, with the probability of damaging the water or heating pipes that pass through the floor (in the case of heating mats)
  • expensive than screed heating cable
  • higher probability of damaging the heating cable during installation of both the floor heating and the ceramic tile


If it is possible to raise the level of the screed and perform a full thermal insulation, then a thick heating cable is a must. In the case of cosmetic repairs with the replacement of the flooring, suitable thin, but more costly solutions. heating mats or a thin heating cable.

Underfloor heating into the screed: pros and cons

The difference between underfloor heating and other types of space heating is the location of the heating elements under the floor covering. This type of heating allows you to get rid of radiators on the walls, which should be placed in two or more rooms, and gives a uniform heating throughout the room, if a warm floor is equipped in a private home.

Installing infrared electric underfloor heating

The infrared (film) heated floor is mounted with some differences from its cable “brother”. Follow the instructions.

Installing Electric Floor Heating under Luxury Vinyl Tile with Self Leveling Concrete

Installation of infrared electric underfloor heating Electric infrared underfloor heating Connection diagram of IPO

Drawing the laying scheme

The first step. Choose a place for installation of the thermoregulator. It is recommended to install it with 15 cm step from the floor surface.

Concealed floor heating controller installation Concealed floor heating controller installation

installation, electric, floor, heating, screed

Second step. Drawing up a scheme of laying the heating system.

Important: The foil cannot be placed under large household appliances, furniture and other heavy objects.

Keep the following important nuances in mind when drawing up the scheme:

  • The first row of the film should be laid with at least 100mm clearance to the wall and no more than 400mm from the wall;
  • If the floor heating will be used as the main heating system, it should occupy at least 70-75% of the total surface area;
  • If the infrared film is installed as a supplement to the existing heating, it is enough to have about 40-50% of the base area.

Lay and connect the system

First step. Lay the infrared film on top of the thermal insulation. Adhere to the lay out. If necessary, the foil can be cut according to the factory lines.

Laying the infrared film on top of the thermal insulation

lay the elements, copper parts of the contacts downwards towards the wall with a thermal controller.

Second step. Connect the contact clamps to the edge of the copper strip and connect the wires.

Infrared underfloor heating design Infrared underfloor heating connection

Step three. Insulate infrared film cuts and connections of clamps and cables. A special bitumen mastic is well-suited for insulation.

Connecting the infrared floor heating

Important: The longer the heating mats, the fewer the contacts should be. Remember: A strip can’t be longer than 8 m.

Install part of the clamps on a current carrying surface. Place the remaining ones inside the heating foil.

Fourth step. Connect the temperature sensor to the underside of the infrared film and insulate it carefully.

installation, electric, floor, heating, screed

Step five. Install the thermostat. Before this, you have to finish laying all the planned material and connect all the contacts and cables. It is recommended to install the thermostat permanently. In the absence of such a possibility you can plug it into the socket as an ordinary electrical appliance.

Experience shows that the bulk of the cables between the thermostat and heating foil is best placed under the skirting board.

Finally, connect the system to the power grid and move on to testing it.

Testing the system after installation

Study the behavior of the system after plugging in. If there is no overheating, sparks or other defects, everything is normal. You can start installing the finish flooring. Before this, it is enough to cover the system with a dense polyethylene film, but some experts still recommend pouring a thin layer of screed. on it the final coating will lay more qualitatively.

Laying of a laminate flooring on top of a thermal floor Warm floor

Pouring on screeds

Before starting work, you should know how to properly pour the screed on the underfloor heating on the screeds. Adhering to the technology, perform screed after all the plaster work, installation of windows and door frames in the room. This is done to create the right temperature conditions for the installation of underfloor heating.

The preparatory stage involves the careful removal of lapping, dust, construction debris. Next, you need to carefully, without haste exhibit screeds under the rough screed. The role of the basis can perform floor slabs, but they need to do flat, if there are deviations from the level. The wall surface from below should be puttied to a level of 15 cm, in order to install a damping strip in the layer afterwards.

Installing the screeds. the main thing is to maintain the horizontality

Now proceed to the arrangement of the rough screed. After completing the filling of the floor is allowed for differences in the area. which is occupied by the water circuit. according to GOST. no more than 5 mm. That is why the installation of the rough floor must be carried out on the screeds. To ensure the highest level of insulation in the room. experienced specialists recommend to use expanded clay screed. Next. Gradually lay the insulation material under the screed on a special adhesive composition. and the joints are sealed with the assembly foam.

After installing the insulation you will need to reinforce the surface with a special mesh. The material should be placed on the heels, so that it was set back from the insulation by 4 cm. After that you need to make temperature seams, to lay pipes / mats / electric wires (depending on the type of floor heating that is installed).

Pour the finishing floor with a solution with plasticizers and screenings (small in diameter fractions of gravel). You can also use ready-leveling mixes, which are designed for underfloor heating systems. At the end of the work should be given 25-28 days for the floor to dry and harden, and then start heating. Self-leveling mixture will dry much earlier. 1-2 weeks. Lay flooring on the dry screed, then turn on the heating system.

Electric floors and their varieties

Depending on the heater used, electric heating floors are divided into two categories: with a heating element in the form of cable and infrared.

According to the method of manufacture, they are divided into 4 types:

  • Heating cable. It can be single- or double-conductor including self-regulating.
  • Heating mats. Is a cable on a mounting grid.
  • Filmed. Polymeric flexible fabrics with built-in infrared heating element.
  • Rod. Consists of carbon rods connected in series.

Electric underfloor heating is calculated on the basis of the size of the furnished part of the room. Under furniture to lay heating elements is not recommended because of the excessive load on the system in these areas. Power of the floor is chosen on the basis of 0, 1 kW/m² on average. This figure differs for different rooms.

It is important before starting to calculate the pitch with which the cable will then be laid. To do this, find the quotient of the area planned for the installation of heating in m², multiplied by 100 and divided by the length of the section in m, taken from the passport.

The following article will introduce you to the arguments and criteria for choosing your own type of floor heating



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