How to choose a substrate for a warm water floor. Do you need a substrate for a heated floor? A substrate for infrared film

Underfloor heating is a "layer cake" in which the underfloor heating system is sandwiched between other components. An important component is the underfloor heating. It must be distinguished from underlayment, which is laid over a heating system, since they perform different functions.

The underlay for a heated floor performs several functions:

• provides additional thermal insulation and prevents heat leakage downwards
• protects the heating system from moisture penetrating from below
• smooths out minor unevenness of the base
• improves sound insulation to some extent
• promotes a more uniform distribution of heat, because the heating elements are located at a certain distance from each other, and thanks to the substrate, the coating warms up not only directly above them
• Almost doubles the surface heating time
• removes heat from heating elements, preventing them from overheating
• reflects heat

The main difference between underfloor heating and other types of underfloor heating is the presence of a heat-reflecting function. The substrate has a foil or metallized coating on top, thanks to which the heat generated by the heating system is reflected and almost completely directed upwards to the floor covering. A special substrate allows you to save from 30 to 97% of thermal energy, so its use with any underfloor heating systems is mandatory.

Requirements for underfloor heating

• resistance to high temperatures and mechanical deformation, as well as chemical inertness (for heated floors that are mounted in a screed or on top of which tiles are laid with adhesive)
• elasticity, ease of installation
• strength combined with low weight (so as not to increase the load on the floor)
• good thermal insulation characteristics (this is the fundamental difference between the underfloor heating underlay and the underlay under the laminate, which is laid on top. The latter must have good thermal conductivity so that underfloor heating can perform its function)
• for rooms with high levels of humidity - good waterproofing properties (infrared film heated floors cannot be laid in such conditions regardless of the substrate);
• vapor tightness
• the presence of a heat-reflecting layer (you can independently combine the substrate with a thin layer of foil or metalized material, but in most cases it is more convenient to purchase the 2 in 1 option)
• If a soft floor covering (linoleum) will be laid on top, the substrate under the warm floor should be as hard and rigid as possible. If laminate or tiles are used as the finishing coating, a softer underlay for a warm floor is needed

Substrates for different floor heating systems

To facilitate installation and ensure safe operation with water, cable and infrared film floor systems, different types of substrates are used.

For water heated floors

For a heated floor consisting of pipes, the most popular solution is a special substrate made of a dense, fairly rigid material with a relief surface, produced in the form of slabs. Typically, it uses molded high-density foam, on the surface of which protrusions (so-called bosses) are located in a checkerboard pattern to conveniently fix the pipes and ensure their bends.

If heated floors are made in a private house, and below there is an unheated cellar or an uninsulated foundation, the foam layer should be as thick as possible.

The waterproofing characteristics of this material are not very high, so it is necessary to lay a film under it; it is good if there is also a moisture-proof coating on top - leaks or pipe breaks are possible.

If the foam substrate does not have a heat-reflecting coating, a layer of foil or foil-clad polystyrene foam is placed on top of it, and if the bosses do not allow this, under it, with the foil facing up.

For electric floor

For cable or infrared rod floors, elastic roll substrates made of foamed polymers (polyethylene, polypropylene) or cork, with a foil or metallized coating, are suitable.

If film infrared heated floors are installed, due to the high risk of short circuits, the use of a foil backing is prohibited, but a metallized coating is suitable. In addition to rolled substrates, wood-fiber or magnesite boards and a layer of metallized lavsan on top of them can be used. Construction aluminum foil can be laid under the slabs.

The only type of heated floors that are laid without a substrate are mats, consisting of a heating cable attached to a flexible base. But only on condition that a substrate with a heat-reflecting layer is integrated into the base.

Some brands of substrates

• DH-Hilon (South Korea) - a polypropylene foam backing coated with metallized lavsan, suitable for any type of electric heated floors
• Ecofol (Russia) - foamed polyethylene with a metallized film, combined with electric and water heated floors, can be used on balconies, loggias
• SEDACOR (Portugal) - cork backing, provides excellent heat and sound insulation, suitable for rooms with normal humidity levels, for use with heated floors an additional heat-reflecting layer is required
• Poliform or Izolon (Russia) - substrates made of cross-linked polyethylene with closed cells, characterized by high thermal insulation characteristics
• Thermodome (Russia) is an affordable, universal substrate for underfloor heating of any type, made of foamed polyethylene with a metallized coating, chemically inert

Features of installing underfloor heating

• The substrate is laid on top of a leveled, cleaned, dry base, preferably with waterproofing
• The heat-reflecting layer should face upward; if it is not integrated into the substrate and there is no possibility of laying it on top of it, it is laid underneath
• Foam plastic slabs are mounted closely, without gaps, strips of rolled backing are installed end-to-end, it is best to connect them together with metallized tape
• Mounting tape is attached on top of the substrate under the cable floor with self-tapping screws. If the substrate under the water floor has a smooth surface without bosses, a mounting mesh must be laid on top

Bottom line

The underlay is an essential component of a heated floor system; some manufacturers even supply it complete with other components. The most important element of the underfloor heating substrate is a heat-reflecting layer, which increases the energy efficiency of the system. If it is not integrated into the substrate, it must be purchased additionally. There are universal underlays for heated floors, and there are those suitable for specific systems. Thus, slab substrates are preferable for water floors, roll substrates are preferable for electric floors, and infrared film floors are not combined with foil materials.

Today, the underfloor heating system is extremely popular. This is due to a large number of positive qualities, as well as the possibility of installing any type of flooring. In addition, you can choose absolutely any option for the heating system, depending on the need and the room itself. But it is worth noting that when installing all components of a heated floor, special attention should be paid to the thermal insulation layer so that heat is not wasted just like that. An excellent option here would be underfloor heating. The main thing is to know which one to choose.

Substrate requirements

The main material for underfloor heating is polypropylene, foamed polyethylene. They are covered with lavsan film having a metallized layer. The latter serves for uniform heat distribution. All other components do not allow heat to escape to the floors below, but are completely transferred into the room to warm the air from the base of the floor.

Particular attention is paid to the substrate. In this option, preference should be given to aluminum foil. Its main task is to efficiently and evenly distribute the heat coming from the heating elements throughout the entire base of the floor. There are two main reasons for this:

1. Creating the same temperature level over the entire surface.
2. Avoiding local overheating of the heating element. All excess heat should be transferred to a less heated area.

The main material for the substrate in this case is polymers or foamed polystyrene. The reflective material is metallized lavsan. You can purchase it in the same place where various underfloor heating systems are offered for sale.

At first glance, this requirement is not mandatory when installing infrared heated floors. But the efficiency of the system, as well as the safety of heating in the room, increases significantly. Even a 30% reduction in heat loss for any system will be noticeable and significant. It is very important to fully adhere to the technology during the installation process and follow it from the very beginning to the end.

Substrate depending on the finish coating

Laminate is the most popular type of flooring. It is distinguished by its low cost and ease of installation. In this case, you should consider purchasing the underlay necessary to separate the covering from the underfloor heating system. Otherwise, there will be a high probability that play will appear in the free areas between the heating elements and the laminate. While walking, this will cause tapping and a certain sound to appear.

The thickness of the laminate underlay is usually 2-5 mm. There is also a specialized material for flooring that has a high level of thermal conductivity. allows you to solve a number of problems:

Many manufacturers recommend using rolled polyethylene as a substrate. In addition, it can be combined with cement. It is able to withstand various chemical influences, as well as the influence of microorganisms that cause the appearance of fungus and mold.

Another option for the substrate is cork, which is sold in rolls or slabs. It is made from pressed chips from cork wood. Preference should be given to rolls by reducing waste throughout the entire “pie”. During operation, the cork will not deform and does not shrink. This will all tell you which underlay for laminate flooring to choose.

Another flooring option is linoleum. Here, on the contrary, the substrate under the heated floor should be solid. Otherwise, heavy furniture or constant walking may cause indentations in the base of the floor. An excellent option is fiberboard.

Often used. Without a heated floor, it tends to remain cold even in hot weather. In this case, for an electric heated floor, it is best to use a lavsan metallized coating as a substrate. This will allow you to heat the tiles with maximum efficiency. The main thing in this case is to use material of the same thickness.

Laying features

Warm floors are essential. The efficiency of the heating system during operation will depend on its quality. Particular attention should be paid to the substrate, which is subject to certain rules during installation.

When making repairs, many people install a heating system not in the form of the usual radiators located along the walls, but in serpentine-shaped pipes filled with a layer of concrete mortar. The top is covered with flooring material, and a substrate is placed under the water-heated floor. Its main purpose is to prevent heat from going down. Let's try to figure out what substrates are and how to make the right choice of this element.

Often, mats laid under a water floor system are made of polystyrene foam and have a thickness of no more than 4 cm. Their main purpose is to minimize heat loss. The raw materials used to make the substrate for heating pipes have the following useful properties:

• resists moisture;
• is light in weight;
• has an acceptable cost;
• does not ignite;
• considered a good soundproofing material.

All of the listed qualities of the substrate allow you not only to create a comfortable microclimate in the room, but also to significantly save on heating.

If the underfloor heating system is installed correctly, the efficiency will allow it to be used as the main heating option. A poor-quality substrate will reduce the efficiency of the entire system.

Underfloor heating will reduce heat loss by almost twenty percent. This is especially important for the first floors, where heat goes into the ground.

In the presence of a substrate, heat is evenly distributed over the entire surface of the floor, minimizing the negative impact on coatings and furniture.

Financial costs for heating and installation of the system itself are significantly reduced. The underlay for a water-heated floor with bosses makes it possible to install pipes in different ways; temporary fixation may not be necessary. Using a substrate with bosses for a water-heated floor, installers can select the most optimal pipe connection points and install sensors that monitor the operating mode. This makes the system control reliable and accurate.

In addition to its main functions, the substrate perfectly protects against extraneous noise, which is especially important for multi-apartment buildings, and is an excellent vapor and waterproofing lining.

Varieties

The substrate for the pipes of a warm water floor can be made of different materials that can provide the necessary properties. Here are examples of the most common options:

• Expanded polystyrene boards are made by extrusion, which gives the material good strength and density. The cells are of a closed type, which has a positive effect on resistance to moisture - the slabs are not afraid of prolonged contact with a humid environment. The initial indicators do not change even when heated to one hundred and thirty degrees Celsius. Expanded polystyrene in its structure contains no more than two percent polystyrene, the rest is air. This feature improves the heat-saving properties of the material. When using this material as a substrate for water underfloor heating, it is necessary to provide expansion joints to prevent the formation of cold bridges at the connecting areas. Expanded polystyrene during installation can be easily cut with a sharp knife, which minimizes the amount of waste. The joining areas are sealed with construction foam. To improve heat conservation, the surface of the substrate is covered with foil. Most often, such a substrate is used in new houses to take into account the height of the premises in the design solution;
• a substrate made of cork material is the most successful solution for its use in this capacity. For production, environmentally friendly cork tree bark is used. It is pre-crushed and special binding components are added. The mass is pressed and dried, the products are sold in rolls or sheets. This substrate has high heat-shielding properties and can withstand heavy loads. To improve performance characteristics, the front side of the substrate under the water-heated floor is covered with foil material;
• Polypropylene slabs are the optimal solution for thermal insulation of a water heating system. The material is not afraid of elevated temperatures and moisture, and is reasonably priced. When heated, its surface does not emit harmful substances and is not exposed to chemical compounds. The slabs may have grooves prepared for laying pipes;
• OSB or chipboard - both options have been used for a long time; large-diameter pipes can be laid on them. The substrates are distinguished by their strength and are classified as middle class in terms of their ability to retain heat. When using them, the mandatory requirement for resistance to moisture must be met;
• metallized film on a natural lavsan base - a modern option used for arranging any heated floor system. It does not tear and can be used on uneven surfaces, speeding up and simplifying installation work. Even when exposed to high temperatures, the substrate is able to maintain its original characteristics. There are also negative aspects - it is distinguished by the ability to absorb moisture, which implies the installation of a waterproof layer.

Basic parameters when choosing

Today, manufacturers offer a wide range of underlays for warm water floors. But the right choice can be made by knowing the main requirements for substrates.

1. An indicator of elasticity and compressive strength. The heating water system is distinguished by its solid weight. The substrate under it should not sag, its thickness should not be reduced. When the load is removed, the material from which the substrate is made should return to its original form.
2. Resistance to negative factors. The stability of the characteristics of the substrate depends on the quality of the material.
3. Low thermal conductivity. It is considered one of the main conditions. The desired requirement in this case is a minimum thickness of the substrate in order to minimize the thickness of the entire heating system.
4. Resistance to prolonged contact with moisture. When operating a water-heated floor, emergency situations arise in the form of a leak of the thermal fluid. And although during installation measures are taken to increase the reliability of the system, an additional obstacle for water will not be superfluous. Another important feature is the percentage of maximum moisture absorption. The substrate material should not get wet, but if this happens, its structure should ensure prompt drying without dismantling the floor covering. Such underlays for warm water floors are good for laminate or parquet, which are not exposed to moisture. In the event of an accident, the underlay for a warm water floor, laid under the laminate, will absorb all the water that has leaked from the heating system without damaging the finished floor covering.
5. Prices. Today's choice of substrates provides a significant range in the cost of this material. An experienced specialist can choose the option that optimally combines quality and price.
6. Versatility. You can assemble the substrate according to the principle of a designer, which makes it possible to change the parameters of the length of the pipeline system and its configuration during the installation process.

The choice can be made taking into account the material for finishing the floor:

• The underlay for a heated floor, finished with a laminate board, must be mounted on a flat surface. To eliminate the shortcomings of cement binder, experts advise using substrates made of soft materials. These can be substrates made of foamed raw materials or coverings made of balsa wood. Preference is given to the roll version, because it leaves a minimal amount of waste. The cork substrate is not subject to deformation and does not shrink;
• If linoleum is chosen as the finishing material, it is recommended to use a hard substrate. Chipboard slabs are excellent in this case, giving the floor hardness;
• finishing with ceramic tiles has one drawback - a cold surface. The main task of a water heated floor is maximum heating. In this case, it is recommended to use polystyrene foam with a foil surface as a substrate, which minimizes heat loss.

Installation Rules

Installation of the underfloor heating under a warm water floor is carried out on a flat surface. In this case, the material from which the substrate is made is important. All work on the installation of the substrate can be represented in the form of a certain algorithm of actions:

• The surface of the subfloor is prepared. It eliminates differences and all irregularities. It is recommended to use a self-leveling mortar mixture for this;
• the floor level is checked, a diagram for laying water pipes is drawn up;
• the substrate is laid. At the same time, its reflective layer remains on the surface. The substrate is laid out in an even layer over the entire surface on which it is planned to install the thermal water floor system. Docking areas must be additionally insulated with mounting materials - tape or adhesive tape;
• if the lining is assembled from several elements, then they are laid tightly, the joining seams are taped with tape with a metallized base. This will improve the steam and waterproofing properties of the floor.

Having completed all of the above measures, you are allowed to begin installing the heating system itself. Experienced specialists recommend laying pipes exclusively on reflective coatings.

If we consider the general requirements, then the substrate for a warm water floor must fully comply with the thermal capabilities of the system and represent an additional factor in their improvement.

After studying all the characteristics of water floor underlays, you can make the right choice to keep your home warm.

Warm heated floors have recently become the de facto standard for constructing heating systems in apartment buildings and private cottages. The use of heated floor systems allows you to create the most comfortable atmosphere in the room.

Underfloor heating - photo

Heating systems in underfloor heating can have different characteristics and operate on different principles. When constructing warm heated floors, you can use any type of finishing floor coverings, so a warm heated floor can be installed in a room for any purpose: in a bedroom or in a nursery, in a kitchen or in a bathroom.

A very important element when constructing a heated floor is its substrate. With its help, the efficiency of the heating circuit is greatly increased, be it an electric heating cable, infrared film or pipes with coolant liquid.

Main characteristics

1. In order to understand what type of underlay you need, you must know what the underlay is for in heated floor systems.
2. So, the underlayment must first of all have excellent thermal insulation and waterproofing properties. It should increase the efficiency of the heating system.
3. An important property of the substrate is its ability to reflect thermal rays.
4. The substrate must withstand temperature changes, working in close contact with the heating elements.
5. Also, the substrate should not allow water vapor formed during heating to pass through.
6. An excellent additional property of the substrate will be sound insulation.

A high-quality substrate is easy to install, has increased resistance to deformation and is environmentally friendly.

This photo shows a rolled underfloor heating substrate, which is equipped with an additional reflective layer with a characteristic metallic sheen.

Features of installing a substrate under a laminate board on a warm floor

One of the most sensitive finishing flooring materials is laminated board. It is made of wood, and, as a result, it has all the characteristics of a wooden board, which has both its advantages and disadvantages. When laying laminate flooring on a heated floor, the use of an underlay is a prerequisite.

In addition to preventing heat damage to the laminate flooring, the laminate underlay also serves as a sound insulator, preventing the finished flooring from being too loud. The minimum thickness of the laminate floor board substrate on a heated floor must be at least 3 millimeters. During operation, such a substrate becomes somewhat compacted without losing its insulating properties.

Step-by-step algorithm for laying a substrate under a laminate board on a heated floor

Let's consider the procedure for laying a foam polyethylene backing under a laminate board on a heated floor.

First of all, you need to clear out your workspace. To do this, you can use a regular broom or vacuum cleaner.

Then we lay the rolled backing on the cleaned surface.

The spread substrate can be secured with double-sided tape, after which you can proceed directly to laying the laminate boards.

Underlay for heated floors with liquid coolant

For any design of heated floors, the substrate must serve to increase the heat transfer of the heating elements. If you use a liquid coolant - that is, you are constructing warm water floors - your substrate can additionally perform the functions of waterproofing the surface.

When installing heated water floors, you can use a substrate that will additionally serve as the basis for installing the coolant piping system. Such a substrate has special protrusions, in the spaces between which the pipeline system is mounted.

As a rule, such a substrate is made of polystyrene foam. One type of substrate for a warm water floor is shown in the photograph.

It must be remembered that a good substrate will be based on foil. If your substrate does not have a foil layer, then it makes sense to place a separate thin foil material on the floor, and then a heat-insulating substrate.

In addition, when laying a warm water floor, you may need to additionally lay the mounting reinforcing mesh, which will serve as the basis for fixing the pipeline system.

In this case, the substrate under a warm water floor will look like a kind of “sandwich”, consisting of a foil layer, a layer of thermal insulation and a layer of reinforced mounting mesh.

A variant of such a substrate is shown in the figure.

Underlay for warm electric floor

The design of the underlay for a warm electric floor is similar to the underfloor heating with a liquid coolant. However, in this case, you may not need additional waterproofing of the surface.

In this case, a layer of substrate is placed on the leveled and pre-cleaned surface of the base, which may consist of a combined material including a foil layer. Next, a mounting tape is attached to the surface of the substrate, to which the heating cable is attached with clamps.

Laying a substrate under a heated infrared film floor

When installing a heated infrared film floor, it is also necessary to use a substrate with heat-insulating and reflective properties. In this case, the substrate is placed directly under the film of the heated infrared floor. In addition to the rolled substrate, you can use wood-fiber board and magnesite boards as a heat insulator.

If your substrate does not have a foil layer, then you can also construct a “sandwich” from insulation and foil.

Penofol insulator can be a good choice as a substrate for a warm film floor.

Backing: penofol

It has a reinforced structure with air cavities that have excellent heat-insulating properties and a foil layer that significantly reduces heat loss in the room.

The foil backing blocks up to 97 percent of heat rays, significantly increasing the efficiency of your heating system.

Important nuances

When laying the underlay on a warm floor under any type of finishing coating, you need to remember several important nuances.

1. First of all, note that the reflective foil side of the backing should be facing up.
2. The underlayment should be laid end to end. In order to prevent heat loss at the joints, it is best to connect the substrate strips with metallized tape. This will also serve as an additional barrier to moisture and steam.
3. Heating elements, be it an electric cable, infrared film or a pipeline with a coolant liquid, must be mounted on top of a coating that reflects heat rays.

If you look at the cross-section of the structure of the classic version of a heated floor, you will see several separate layers. Each of them has its own purpose, and neglecting any of them will negatively affect the overall efficiency of the heating system. One of these structural elements is the underfloor heating.

Where and why is the substrate located?

The question of the location and purpose of the underfloor heating depends on its design. To better understand the value of this element, it is necessary to consider in detail the very structure of various heating systems.

Underlay for electric floors with cable heating

Although this version of the heating system requires the greatest effort to implement, it can be considered a classic version of a heated floor. Before starting its installation, you must complete the following work:

• applying a rough screed to level the surface (if necessary);
• creating a layer of thermal insulation;
• applying a screed that covers the thermal insulation and acts as a basis for the heated floor.

After this, the actual creation of the heating system begins. Initially, a substrate is placed under the electric heated floor, on top of which mounting tapes are attached with self-tapping screws. The heating cable will be secured in these tapes. After its placement and connection to the network, the location of the sensor, everything is filled with cement.

In this design of the heating system, the substrate under the heated floor is made of aluminum foil. Its purpose is to distribute heat from the cable evenly across the entire floor. This is necessary for at least two reasons:

1. Ensuring the same temperature throughout the entire room.
2. Elimination of local overheating of the cable and removal of excess heat from it.

As can be seen from the description given, the underfloor heating with such a heating system allows you to increase the service life of the heating cable. This happens due to maintaining its optimal operating mode, and also improves the temperature distribution in the room by heating its entire volume. We should not forget about the implicit positive consequences that such a lining under a warm floor provides.

With a heating system based on a heating cable, the air in the room receives heat from the floor. The larger the volume of the floor is heated, the longer it will take to cool, the less energy it will consume. Such an increased temperature is ensured, among other things, by the underfloor heating; it is simply necessary to buy and install it when installing the heating system.

Underlayment for floors with infrared heating

When using infrared film, the design of the heating system differs significantly from the classical one described. Although in this case a substrate is used for infrared heated floors, its purpose is different.

In the case of using IR film and cable, their work as heat sources differs. If the latter acts directly on the floor, which warms the air throughout the room, then IR radiation increases the temperature of the floor covering and the surrounding environment (walls, furniture), and from them the heat is transferred to the air in the room.

When installing such heating, the surface of the existing floor itself acts as the base of the heated floor. Waterproofing is laid on it (not always, only if necessary), and on top is a layer of heat-insulating reflective material. This is exactly what will be the substrate for the film heated floor. IR film is laid on this substrate, individual sheets of which are connected to each other, maintaining polarity, and then connected to the network.

There is one obligatory condition for the material used - foil underfloor heating is unacceptable, in any case, the use of aluminum foil as a reflective material is strictly prohibited. This is due to safety requirements; in case of any defects in the contacts, a short circuit to the substrate may occur.

The function of such material in the construction of a film floor is twofold. On the one hand, it acts as a thermal insulation material, on the other, as a reflective IR radiation directed not into the room, but into the floor. A similar underfloor heating material, the price of which, by the way, is quite affordable, helps to avoid up to 30% of heat loss.

Such heat-insulating reflective pads for the heater are usually made of foamed polystyrene or polymers; metallized lavsan is used as a reflective material. In the design of a film IR heating system, it is mandatory to use such a underfloor heating substrate; you can buy it in the same stores where the heated floors themselves are sold.

There is nothing surprising in such a requirement; it is this requirement, insignificant at first glance, that ensures high operating efficiency and safety of heating. In this case, whether such a underfloor heating is installed or not, its price is 30% savings from heat loss. And this is a lot for any system. So you just need to follow the technology.

Despite its, at first glance, insignificance, the substrate placed under the heated floor plays an important role in ensuring the efficiency of the entire heating. Moreover, its tasks differ in different heating implementations. However, it is essential for the efficiency, safety and cost-effectiveness of any system.