The floor is the coldest of all building envelopes. Given that a person is constantly in contact with the floor surface, homeowners have long sought to make this contact comfortable. Laying insulation for finishing floors, cladding with materials with high thermal insulation characteristics are passive measures in this direction, since they are aimed only at preserving heat in the room, and not at generating it. The emergence of systems, commonly called «warm floors», has become a solution to the problem, moreover, not only comfortable contact with the floor surface, but also their heating.

Heated floors have long ceased to be exotic, but the rather high cost of arranging housing with them still prevents the widespread use of this equipment in everyday life. However, users who have equipped their homes with underfloor heating and appreciated their merits are striving to expand the scope of these systems, even putting up with a decrease in their effectiveness.

Underfloor heating under tiles on a balcony with panoramic windows

Let’s consider how to install a warm floor on a balcony, without confusing it with a loggia, and the validity of this operation.

Types of underfloor heating systems

The task of heating equipment of this type is to increase the temperature of the floor finish to a value that is comfortable for contact with the human body. This is achieved by heating the layer arranged under the floor cladding, in which the heating circuit is located. This layer can be made of cement-sand mortar or other material, depending on the type and design of underfloor heating.

The principle of operation of a warm floor

The heating circuit releases heat to the surrounding material, which in turn transfers it to the finish. Heated floor cladding initiates air convection from the floor to the ceiling — uniform, without concentrated flows, which leads to a more comfortable mode of heating the room.

Comparison of convection from a radiator and underfloor heating


According to the origin of the heat given off, the heating circuits are divided into water and electric. Underfloor heating that uses water and electricity also received the same name.

Floors with water heating

heating circuit such a floor is a flat coil of a tube through which a coolant circulates — hot water or an antifreeze solution. Moving along the contour, the liquid through the walls of the tube gives off heat to the environmental material and again enters the heater.

Types of layout of the water heating circuit

The source of hot water for the heating circuit can be a central heating system or an autonomous boiler.

In the first case, the coil does not need additional equipment, only shut-off valves are needed at the tie-in points.

If it is planned to install warm floors from an autonomous boiler, then, in addition to the circuit, it is necessary to install an expansion tank and a distribution unit with automatic control.

Electric heated floors

In electric underfloor heating, the heat generator is a heating circuit, which is connected to the household network through an automation system.

Electric underfloor heating is produced with three types of heating circuits:

  • cable;
  • in the form of mats;
  • infrared.

The first type is made of special small-section self-regulating cables that heat up when current passes through them, the second is an improved version of the first (laid on a base), the third is made of infrared plate radiators.

Features of the operation of balconies

Both closed and open balconies are structures that have a special location that determines individual constructive and operational characteristics.

  • Balcony slabs do not have supports under the outer side and protrude from the load-bearing walls of the facade like consoles. In this regard, balconies, according to GOST, their maximum load is only 200 kg / m2.
  • The enclosing structures of the balcony rooms from the side of the street are thinner, and therefore it is much colder in these rooms in winter.
  • The balconies of the upper floors are difficult to access for outdoor work.
  • The glazing area of ​​balconies is usually significant, and what adds another negative factor is water on the floor.

Based on these features, the following conclusions can be drawn:

  • The installation of underfloor heating on the balcony without performing the insulation of the enclosing structures is inefficient.
  • Thermal insulation of balcony walls and floors should be made of lightweight materials, easier — from the inside.
  • The finishing of the floor surface of the balcony in the area of ​​possible contact with atmospheric moisture must be moisture resistant.

Let us consider in more detail how to make the thermal insulation of the enclosing structures of balcony rooms.

How to insulate the floor on the balcony


During the operation of underfloor heating, the maximum heat loss will be through the balcony slab. If the balcony of the neighbors from below is not heated, then the heat loss will be even more significant. This means that the implementation of thermal insulation of the supporting base is mandatory, and the technology is selected depending on the design of the balcony and the height of the ceilings.

In private houses with high ceilings and loggias, the slabs of which are based on columns or walls, the choice of floor insulation methods is wide — you can use both solid sheet polymer materials (foam, polystyrene, polyurethane foam) and loose (expanded clay, slag), laid with a layer of necessary thickness.

For apartment balconies, it is necessary to choose a material with reference to the situation, and to the detriment of efficiency, reduce the thickness of the bulk insulation.

In order for the effect of expanded clay thermal insulation to be acceptable, the layer of it must be at least 5 cm, and for high-quality performance — up to 20 cm.

Insulation of the balcony floor with expanded clay

The name «expanded clay» means expanded clay sand and gravel of various sizes of fractions. As a heater, this material has been used for a long time and is popular to this day, since, with the availability of the price range, it is close in merits to modern heat-shielding materials.

Gravel expanded clay is produced in the following fractions:

  • 5–10 mm;
  • 10–20 mm;
  • 20–40 mm.

Fraction up to 5 mm is called expanded clay sand.

The larger the fraction, the higher the thermal insulation characteristics of expanded clay, but at the same time, its susceptibility to shrinkage is greater.

Expanded clay is a hygroscopic material, and, after getting wet, it loses its heat-insulating properties, and dries for a long time. Therefore, the floor for laying expanded clay must be equipped with vapor and waterproofing so that the moisture of the concrete does not accumulate in the insulation. For this purpose, a technical polyethylene film with a thickness of 0.5 mm is suitable, the laying of which is carried out with an overlap of 5-7 cm strips on each other, and 10-15 cm on the walls. There are no high requirements for evenness of the concrete base, but bulges with sharp edges should be cut down from it, and shells with a depth of more than 3 mm should be filled with cement mortar.

Checking the quality of the surface of the bearing concrete base

Important! The strips of the top layer of polyethylene are laid across the bottom, and the overlaps of the film are coated with bituminous mastic from the inside.


On top of the obtained vapor barrier coating, expanded clay is laid to the intended level. To facilitate the subsequent leveling of the surface of the filled-in insulation, you can first install “beacons” or temporary guide rails on the floor.

Alignment with a lath of laid expanded clay

If the height of the ceilings allows, it is better to backfill in two layers, placing a fraction of 5-10 mm below, and 10-20 mm on top.

Then, along the perimeter of the room, a damper tape 10 cm wide is glued to the wall along the edge of the expanded clay, which will take on the thermal expansion of the materials to be laid.

A reinforced cement-sand mortar screed 5 cm thick is arranged on top of the expanded clay insulation layer. A mesh with a cell of approximately 10×10 cm made of steel or fiberglass rod is used as reinforcement, which is easily knitted with one’s own hands. Before pouring concrete, the mesh is laid on expanded clay and positioned so that its plane is located closer to the lower surface of the future screed.

Scheme of the device for floor insulation with expanded clay

At the end of the pouring, the concrete is covered with a cellophane film and within 28 days it is provided with a full set of strength.

The floor is identically insulated with solid heat-insulating materials, for example, extruded polystyrene foam (foam foam) 3-5 cm thick — a durable sheet insulator that can withstand the load from the weight of a person standing on it.

It is convenient to install screed beacons on this material — screw long self-tapping screws to the desired depth. The height of the ceilings when using foam plastic suffers less, but the price of this material is higher than the cost of foam plastic and expanded clay.

Wall insulation


Given that the hardness of the insulation for walls is not of fundamental importance, today there are many materials with suitable characteristics — mineral and polymer, sheet and roll, hard and soft.

If we are talking about housing, it is better to abandon the use of mineral wool materials — due to their hygroscopicity, they need additional protection.

Consider the device for thermal insulation of walls using sheet polymer insulation using one of these materials as an example.

Balcony wall insulation with polystyrene foam

This insulation is one of the varieties of foam, widespread in everyday life and often referred to as such. This material has many advantages, and at the same time it is cheap.

The method of fixing the expanded polystyrene to the wall depends on the base material and the planned finish.

Insulation from the inside to the wall can be mounted in the following ways:

  • glue on PVA or other composition that does not contain aggressive solvents;
  • mount on special wedging fungi;
  • insert into a frame of wooden bars or cd-profiles.
Internal thermal insulation of the balcony walls

And on top of the insulation, the following finish is used:

  • reinforcing paint mesh, followed by puttying and painting, wallpapering;
  • cladding along the frame with plastic panels, siding or clapboard.

Having completed the insulation of a balcony or loggia with polystyrene foam, you can expect not only pleasant contact from warm floors, but also heating the room.

Heated floor of a residential balcony under a tile

Having considered the methods of warming the carrier plate and walls, you can proceed to the choice of a floor heating system.

Of the two main groups of this equipment — water and electric, systems on the water seem to be more attractive. But the installation of the water heating circuit is carried out in a 5 cm thick screed. Considering that the floor was insulated under it, followed by the laying of a bearing layer of concrete of approximately the same thickness, for the balconies of most old apartment buildings such a load on the base will be dangerous.

In addition, in such houses, connection to central heating requires coordination, and in 99% of cases it will not be successful, since the additional load from the operation of underfloor heating in individual apartments unbalances the entire water heating system of an apartment building.

Important! If the room is small, then connecting its underfloor heating system to central heating may not affect the quality of heating the house as a whole, but such unauthorized actions are fraught with fines.

Therefore, warm floors on the water are not suitable for old houses.

Then we will consider modern houses with a free layout, for example, project P44T, in which the connection of warm water floors to central heating is allowed.

Connecting the underfloor heating on the balcony to the central heating

At first glance, this solution has a significant a plus in the form of low cost performance (no need to purchase water heating equipment) and the absence of energy costs.

Connecting the water heating circuit to the central heating

But further analysis of the situation somewhat reduces enthusiasm due to the following cons:

  • dependence on the operating mode of the boiler house (beginning and end of the heating season, emergency, scheduled work);
  • possible unacceptability for the installed equipment of the parameters of the coolant in the system, especially the temperature (up to 700C), while in the contour of warm floors it should not exceed 400 FROM.

However, central heating is not the only source of hot water.

Floors with autonomous water heating

If you refuse to connect to the central heating, then the water floors can be connected to an autonomous boiler, if, of course, there is one. But even if it is available, in addition to mounting the circuit, it is necessary to install an expansion tank and a distribution unit with automatic control.

distribution node (collector, mixing unit) is an automatic system of valves and regulators responsible for the temperature of the coolant at the inlet to the circuit. Depending on the manually set temperature values, the distribution unit adds the required amount of hot liquid to the cooled coolant.

Collector of a water heat-insulated floor

The installation of this equipment will require additional space and, most importantly, such a solution to the problem is associated with significant material costs.

That is why the installation of water heated floors is most often carried out in the premises of medical and children’s institutions, less often in spacious private houses.

The conclusion suggests itself quite unambiguously — if there is an autonomous heating unit of sufficient power in the apartment, the installation of floors with water heating is technically possible, but not economically justified.

Electric heated balcony floors

Installation and operation of electric floors also have their own characteristics:

  • under the floor finish of tiles, it is better to choose a circuit from a heating cable;
  • if they want to avoid dirty work and also do the installation themselves, then they prefer the film infrared version.

In everyday life, an electric underfloor heating system is called a system with a heating circuit made of a special cable with a diameter of up to 5 mm. Such a wire is laid with a “snake” on a layer of foil foam foam, located with the foil up, and is fixed on it with brackets with a certain step along its entire length.

Important! Penofol is laid on top of a concrete screed over the main foam insulation.

The coils of the «snake» are located at a distance of 10-15 cm from each other, as in the case of laying water floor pipes.

Watching the video will add clarity to the presentation:

This technology is quite laborious, therefore, at present, contours assembled from so-called “cable mats” are more popular. Electric mats are a heating cable with a diameter of 2-2.5 mm, also “snake” fixed on a strip of fiberglass mesh.

Set of electric floor heating mats

Steam and heat insulation under heating mats are arranged identically to the water system, but for laying tiles on top of them there is no need to perform another screed — a concrete layer above the main insulation is enough. Ceramics can be glued directly onto the mats, but the tile adhesive is applied to both the base and the tiles with a comb trowel in layers of 10 mm each.

Video on underfloor heating on mats:

Electric heated floors of any kind are equipped with a control unit consisting of a temperature sensor and a control panel. The sensor is attached between the turns of the «snake», and the wire from it is led along the contour plane to the panel on the wall.

Scheme of connecting warm electric floors to the network

Important! When using a heating cable, the power of the underfloor heating system is determined at the rate of 200 W / m2and cable mats — 150-160 W / m2. When choosing a system, there is no need to take into account the linear power of the cable — this has already been done by the manufacturer, and it is impossible to cut the cable.

Laying the contour should be done only in open areas of the balcony floor, without placing it in hard-to-reach places.

Infrared heated floor on the balcony

Heated floors of this type are by far the most popular for arranging balconies, due to the ease of installation, which takes only a few hours.

infrared heating film

Infrared radiation in such systems is directed only towards the room, but you still have to perform thermal insulation of the floor, otherwise, after turning off the equipment, the floor surface will quickly cool down.

The installation of the infrared film is carried out on a foil isolon — a continuous coating is made from it, gluing the joints of the material with adhesive tape with foil.

Sealing the joints of foil foam

Then, holes are made under the locations of the temperature sensor and film connection contacts so that these parts do not protrude above the surface.

Film webs are cut according to the standard markings applied to them by dotted lines. Then the film is laid on the isolon and connected to the control panel in a parallel way with the obligatory subsequent isolation of the contacts.

Marking on IR film for cutting

The temperature sensor is installed in the same way as the version with cable mats.

On top of the infrared film, waterproofing is carried out from technical polyethylene — a coating of strips with laps of 10 cm, after which the topcoat can be laid on it.

Video hint on the technology of mounting IR film on the floor:

Heated floor on the glazed balcony under the laminate

Based on the conclusion that it is better to use electrical systems for installing underfloor heating on a balcony, we will consider which of them are optimal for laminate flooring.

Laminate on infrared and cable underfloor heating

It is better to start with the power required for heating.

The intensity of heating with an infrared film system is higher than with a cable circuit. That is why to calculate the required power in the first case, a value of 200 W / m is taken2and in the second — only 160 W / m2.

Laminate is a material with low thermal conductivity. Therefore, under such a lining, an infrared system will be more effective. In addition, it does not require a screed — the laminate can be laid directly on top of the infrared film, having previously completed a polyethylene waterproofing on it.

Combined underfloor heating

The use of cables or mats on a balcony or loggia under a laminate is also not excluded, but, given the variable cross-section of the contours of these systems, it will be necessary to perform a load-bearing screed with reinforcement on top of them in order to protect the conductive elements from breaking when loaded from above. And this is an additional cost and load on the base.

Over time, with abrasive wear of the laminate, you can not rush to dismantle it, but use this coating as a base for linoleum.


To increase the functionality of balconies, they are closed and glazed, and then insulating the resulting room is no longer a desire, but a necessity.

Of all types of underfloor heating, infrared film is most suitable for a balcony, which should be the starting point. Experimenting with permissible loads on a balcony slab can end in failure.

The main essence of the article

  1. Underfloor heating is an effective technology applicable to most types of premises.
  2. The two main types of underfloor heating systems are water and electric.
  3. The choice of the optimal floor heating option is carried out with reference to the heated room.
  4. Balcony — a structure with a special arrangement, causing restrictions on the permissible loads.
  5. Balcony insulation when arranging underfloor heating is a must.
  6. The choice of a balcony insulation method should be tied to the specific gravity of the insulation.
  7. Installation of a water-heated floor for a balcony is at least not advisable.
  8. Electric underfloor heating is a group suitable for selection, but for do-it-yourself execution, an infrared system is the best option.


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