What kind of insulation to choose for a water-heated floor. Thermal insulation for a warm floor system: a comparative review of insulation materials Floor insulation under a warm water floor

Heaters for creating a warm water floor save energy. They reduce heat loss by 15-20%. Their main task is to prevent the penetration of radiant energy into the ground, lower rooms or basement.

In the general system, a heater for a warm floor performs several functions. It does not allow unnecessary heat loss and ensures uniform heat distribution. In addition, any material becomes an additional noise barrier.

When reviewing options, it is important to consider the key features of thermal insulation for underfloor heating:

• low coefficient of thermal conductivity;
• resistance to dynamic and static loads that will arise during operation;
• shape stability;
• long service life.

In addition, thermal insulation for a warm floor must be fire resistant and safe.

Manufacturers offer a wide range of insulation materials that differ in structure, thickness and characteristics. When choosing, one should take into account the peculiarities of the room where the underfloor heating system is installed, a possible increase in the height of the structure, and the characteristics of thermal insulation.

Popular materials

Expanded polystyrene. Foamed polymer material. It is distinguished by good thermal performance, light weight and affordable price. Plates do not rot and do not allow moisture to pass through. The disadvantage of expanded polystyrene can be considered a relatively low sound insulation performance.

Leading manufacturers offer special insulation under the warm floor with bosses. Thanks to the special protrusions, the laying of the water floor pipes is not difficult. The material is distinguished by increased strength indicators, it is protected against condensation. Foil mats are also on sale.

Foil mineral wool. Insulation under a water-heated floor is offered in the form of rolls or dense slabs. It is made from natural raw materials and belongs to the class of non-combustible materials. Basalt mats, which are characterized by high dimensional stability, are especially popular. When working with them, a minimum amount of dust harmful to the body is released. The main disadvantage of mineral wool insulation is considered to be increased sensitivity to moisture. When wet, they lose their insulating properties. The presence of a foil layer reduces this likelihood.

Natural cork. Thermal insulation for a water-heated floor is made from the bark of a cork tree. By pressing, a thin roll material 3-4 cm thick and dense mats are obtained. The insulation is characterized by:

• safety - the insulation is environmentally friendly and hypoallergenic;
• good indicators of heat and sound insulation;
• resistance to the processes of decay and destruction by rodents;
• stability of geometry;
• waterproof.

Almost the only drawback of natural cork is its high cost.

Penofol. This type of thermal insulation for a warm water floor is made on the basis of polyethylene foam. The polymer layer is coated on one (type A) or two (type B) sides with aluminum foil. A self-adhesive version (C) is also available. If you plan to pour a concrete screed, then the type of ALP should be used in the underfloor heating system - the foil layer is laminated with a polyethylene coating.

The air present in the structure prevents heat loss, and the metal surface contributes to its reflection into the room. The total thickness of the insulation does not exceed 10 mm. Compact rolls are easy to transport and stack.

Metallized lavsan film. Non-combustible floor insulation with perfect reflective performance. The material is inert to aggressive chemicals and microorganisms.

Waterproofing performance ensures that the system is protected from moisture penetration from the basement or the ground. The film is elastic, has sufficient strength to deformation, and can withstand high loads.

The metallized layer is often supplemented with polyethylene foam with a thickness of 2 to 10 mm. This improves the thermal insulation performance, but reduces the flammability class of the material. Lavsan film can withstand temperatures up to +90 ° C without destruction and deformation. This allows pipes to be laid directly on top of it.

The main characteristics of heaters are shown in the table:

Insulation Indicators	Expanded polystyrene	Minvata foils	Cork	Penofol	Lavsan film
Thermal conductivity, W / mK	0,0336-0,035	0,035-0,045	0,036-0,042	0,037 - 0,052	0,031-0,037
Moisture absorption%	0,2-0,4	0,1-0,2	1	0,35-0,7	0,1-0,2
Water vapor permeability, mg / m h Pa	0.05	0,49-0,60	0,2-0,6	0.001	0.001
Flammability, class	G1-G4	NG	D1	D1	D1
Service life, years	50-100	more than 50 years		20-25
Operating temperature range, ° С	-50 – +85	from -200 to +700	from -200 to +130	from -40 to +95	-60 - +100
Sound absorption coefficient,%		85-90			52
Noise absorption, dB	23-28		10-12 for black, 16-20 for white	20-32

Manufacturers and prices

High-quality insulation for warm floors is offered by many leading manufacturers. Some options are suggested in the table:

Insulation type	Brand name	Options	Cost, rub. per m2
Expanded polystyrene	Knauf Therm	1200x600x47 mm	500
Ecopol		1100x800x38 mm	455
Foam shield		1000x1000x50	270
Foil-clad mineral wool	URSA (fiberglass)	roll 18000х1200х50 mm	115-168
Rockwool (basalt)			342
Technical plug	Amorim	1000 × 500 × 10mm	560
Penofol	Penofol	roll type A (B)	47 (78)
Lavsan film	Daewoo enertec	roll 1х30 m, thickness 3 (5) mm	139

Styling features

In order for the underfloor heating system to function effectively, it is important to perform all the installation steps correctly. An important role is played by the laying of insulation. Work begins with surface preparation:

• elimination of large cracks;
• leveling the base;
• arrangement of waterproofing- the material is laid over the entire floor area with an overlap of 15-20 cm, the joints are glued with tape;
• installation around the room damping polystyrene foam tape. It is glued to smooth walls, and attached to rough walls with self-tapping screws. The tape should be 2-3 cm higher than the finished floor.

After that, they start laying the thermal insulation. Plates are laid end-to-end, without gaps. To avoid the formation of cold bridges, the joints are treated with a sealant. The fastening method depends on the selected material.

Subtleties of the connection of the insulation with the foil base

Heaters with foil are laid with a reflective surface up. This ensures efficient return of heat energy to the interior of the room. During the installation process, care should be taken to ensure the correct connection of individual plates or strips. Conventional construction tapes and adhesives are not suitable. A special version of foil tape with an adhesive backing should be used.

Output

Heaters for a water-heated floor allow you to effectively retain heat and guarantee a reduction in energy consumption for heating. Additionally, they serve as soundproofing. Materials are presented in a wide range. The choice should be based on the characteristics of the premises and personal preferences.

"... Thermal insulation layer
The main purpose is to prevent heat losses down. The heat must go up into the heated room. It can be made of any materials permitted in construction as an insulating layer for use in floor construction.

No matter what material the thermal insulation layer is made of, the following condition must be met:

The thermal resistance of the thermal insulation layer must be greater than the total thermal resistance of the heating layers (including the finishing coating) at the maximum thermal load on the water-heated floor.

The greater the heating load, the thicker the thermal insulation layer.

The higher the thermal resistance of the finish coating, the thicker the thermal insulation layer.
The most common thermal insulation material in modern construction is polystyrene. It is recommended to use polystyrene with a density of at least 35 kg / m3. Polystyrene of lower density is not resistant to mechanical stress, collapses if not used carefully and loses its mechanical and thermal insulation properties, especially when, against the background of ongoing general construction work, a long time passes from the end of the installation of pipes for the water floor heating circuits to filling them with a screed. Polystyrene with a density of 50 kg / m3, as well as extrusion, is used in systems with high mechanical loads (auto centers, warehouse complexes with heavy forklifts, road heating, etc.).

ATTENTION! Russian manufacturers (for the most part) produce polystyrene according to TU, and not according to GOST: the numbers in the product name (for example, PSBS-25, PSB-35) do not indicate the density of polystyrene. The actual density, as a rule, is "one step" lower than the figure appearing in the stamp. Be careful when choosing materials. ... "

On the ground from 8-10 cm of expanded polystyrene. Interfloor floors - 2-3 cm of expanded polystyrene.

You can safely FORGET everything else.

About foamed polyethylene 2 mm)]) with foil incl.

Foil saves only a few percent.

Foil, not protected by a film, collapses in concrete in 2 weeks.

Those. in the basement, you can use Extruded polystyrene foam URSA XPS, 50x600x1250mm, pl. 35kg / m3

And on floors with 3cm thick slabs?

Or is it worth putting in a thicker one in the basement, just in case? and on the floors to put 5cm 35kg / m3?

And give advice which screed is better to lay 3 or 5 cm? and on top to lay down tiles or laminate with what will be warmer? I just read a person's tile floor is very hot and the laminate floor is not even warm.

Please advise more pipes, otherwise the company offered me prices from 0.45 euros to 1.25 euros per 1 m. Pipes so which ones are better to buy so that they would be warm and durable?

Hello Dear blog readers! Agree that spring is long-awaited, it's good: everything is awakening, everything is striving further, into warmth, into summer. And then suddenly - bam! - winter returns, with frosts, snowfalls, strong winds. After all, nobody has canceled the vagaries of the weather. That is why a human dwelling should be doubly strong, so as not to shiver in the cold, and not to languish in the heat from stuffiness. But now about the first - about the cold. Let's once again think about warm floors, this time about water ones. And all because today we are interested in insulation under a warm water floor.

What is this insulation for? A reasonable question, let's try to answer. Underfloor heat insulation helps to distribute heat evenly in the room. Roughly speaking, the warm floor resembles a kind of layer cake, and the heat-insulating material is a very important component of this “dish”. Without insulation, the functioning of the heating system would be ineffective, and the system itself would hardly be distinguished by its durability in operation. That is why any heated floor must be fitted with insulating materials.

Let's summarize preliminary results. So, insulation (thermal insulation) solves several problems:

• With its help, the heat energy is evenly distributed throughout the room. This is especially true for a water-heated floor, since its heating system consists of pipes bent in some places, and without a layer of insulation, heat cannot evenly enter the room.

• Thanks to thermal insulation, the heat practically does not leave the premises. In other words, the insulation does not allow heat to "seep" through the ceiling and be wasted - it accumulates it.

• In many cases, thermal insulation helps to simplify the installation of underfloor heating.

We sort of figured out the general concepts. Now let's move on to the technical details: they are equally important.

The thickness of the insulation plate under the warm water floor

I must say that the material from which the insulation is made can be different. The best known is expanded polystyrene. In some of its properties, it is similar to foam, but its performance characteristics are much more practical. For insulation, mineral wool, ecowool, cork material and others are also used.

But not only the properties of the material used for insulation affect the performance of thermal insulation and its ability to retain heat. An important role is played by such a parameter as the thickness of the insulating layer.

Since we are talking about underfloor heating insulation, it makes no sense to pay attention to climatic conditions when determining the thickness: the underfloor heating heating system itself neutralizes climatic contrasts. However, there are still certain rules. So, if expanded polystyrene is used, then it is recommended to use a sheet with a thickness of at least 30 mm. In addition, for the highest efficiency and maximum density, the sheets are reinforced with a polymer cloth, which contains a reinforcing mesh.

By the way, you can buy a ready-made polystyrene foam insulation for a floor with a water heating system, which has a special marking. Such sheets are completely ready for use, all that remains is to remove the excess. By the standard, they are square with a side length of 50 cm.

It must be remembered that underfloor heating is not just pipes "hiding" under the floor covering and heating rooms. In fact, this is a multi-layer system, and the full operation of the warm floor as a whole depends on the quality and correct installation of each layer. If such a floor is deprived of insulation, then during the winter it may well lose about 25% of the heat. Agree that this is a lot. That is why high-quality thermal insulation is so necessary.

Insulation under a warm water floor on a rough concrete floor

A good insulation under a water-based underfloor heating is, in particular, penoplex. Its sheets are laid out on a primed concrete base, covered with polyethylene, which acts as a waterproofing, and only after that the heating elements are mounted.

I must say that the use of underfloor heating (water heating system) when installing thermal insulation will make your floor resistant to moisture and extend its service life. What does an effective water floor with maximum results ultimately consist of? These are the components:

• A rough concrete floor or screed to trap heat from lowering and exiting.

• The thermal insulation is foil so that the heat is reflected back into the room. The use of foil-clad thermal insulation significantly reduces heat loss, which leads to a corresponding increase in the temperature in the heated room.

• Insulation, which, while retaining the maximum amount of energy, reduces electrical costs. We once spoke in detail about the electrical costs from the warm floor in an article - I advise you to familiarize yourself.

Thus, it turns out all the same mentioned "pie", but with the correct "filling", therefore, useful and durable.

How exactly it is necessary to install insulation under a warm water floor, how it looks and how it happens, can be seen in the photographs we offer. It is on top of the heaters presented below that the underfloor heating system is laid in the future.

What kind of insulation to put under the underfloor heating system? Let's find out what are the popular types of thermal insulation materials, their strengths and weaknesses. I will tell you about 5 insulation options that I personally used in the repair process.

Types of materials and their description

Popular thermal insulation for underfloor heating:

• Styrofoam;
• Extruded polystyrene foam;
• Mineral wool;
• Penofol;
• Heat-insulating assembly mats for underfloor heating.

Option 1 - Styrofoam

The most popular option due to the following advantages:

• Availability... The material can be purchased at almost any hardware store;
• Cheapness... The price per square meter is from 100 rubles per square meter;

• Large assortment of products... You can purchase material with a density of 15 to 35 kg / m 3 and a thickness of 20 to 200 mm. For use on the floor, I advise you to choose options with a density of 20 kg and a thickness of 30 mm;

• Versatility... The material is suitable for water, infrared and electric underfloor heating.

The option also has disadvantages:

• Low material strength... Under high loads on the flooring, the surface can be squeezed. To avoid this, it is necessary to make a screed of at least 6 cm;
• Inconvenience of installation. It is difficult to tightly connect the sheets with your own hands, so the joints need to be filled with polyurethane foam or the sheets should be fixed on the surface.

The process of floor insulation looks like this:

Illustration	Stage description
	Styrofoam is laid on the floor... The material can be laid on concrete screed, slabs or rough wooden flooring without preparation. The most important thing is to place the sheets tightly so that there are no gaps between them.
	Elements are fixed with dowels... Special fungi are used to fix the thermal insulation. All gaps are filled with cement mortar or polyurethane foam.
	The film is laid. The process is simple: the material is covered with gaps of 10 cm on the walls; the joints are glued with ordinary tape.
	Foil is covered for infrared systems... Reflective material can be used for other types of flooring, but is not required. Penofol is often used instead of foil, it creates a reflective surface and makes the surface even warmer.
	A warm floor is laid on top of the insulated surface... It all depends on the type of construction. The surface is well prepared and suitable for any system.

Option 2 - boards made of extruded polystyrene foam

Extruded polystyrene foam or, as it is also called, Penoplex is an improved version of polystyrene foam. Its main advantages are as follows:

• High thermal insulation performance... Penoplex is 40% warmer than ordinary polystyrene, which allows the use of elements of smaller thickness when insulating;

• High strength... Of all the thermal insulation materials that I talk about in the review, this one is the hardest and most durable. Therefore, Penoplex is ideal for rooms with high floor loads;
• Convenient connection system... The presence of grooves at the ends allows the sheets to be joined very tightly. This increases the efficiency of insulation and simplifies the work, you just need to combine the elements all the way;

• Durability b. The service life of the material is 50 years or more. Extruded polystyrene foam is not afraid of moisture, mold, chemical influences.

Of the significant drawbacks, one can be distinguished: high cost. A square meter of insulation 5 cm thick will cost you 250-300 rubles.

The installation instructions are simple:

Illustration	Stage description
	Penoplex is laid on the floor... The sheets just fit tightly together. The elements are trimmed along the edges, narrow areas can be laid in pieces, after which it is recommended to carefully fill all the cracks with polyurethane foam.
	Reinforcing mesh is laid a. If you are laying insulation under a warm water floor, then you can use this option for carrying out work. It is simple, because you need to put a mesh, and you can immediately attach floor heating pipes to it. It is convenient and reliable.
	Reflective material can be placed under the reinforcing mesh... This option allows you to reflect heat into the room, so I recommend not to save money and put a layer of foil or Penofol on the surface.

If you are laying an infrared floor, then the foil is not covered over Penoplex, but over the screed, after pouring the surface under the heating mats, so the system will be much more effective.

Option 3 - mineral wool boards

This insulation option for an underfloor heating system has the following features:

• High quality insulation... Mineral wool has good thermal insulation characteristics and is excellent for structures in which complete insulation of the cold surface is of the utmost importance;

• Compatibility with all materials... If foam and extruded polystyrene foam are not very suitable for wood, then mineral wool is an excellent solution in all cases. It is recommended to use mineral wool for wooden floors;
• Environmental friendliness... The material does not emit any harmful substances into the air, is not damaged by rodents and does not support combustion.

The disadvantages are as follows:

• High price... For a square meter of high-quality mineral wool 5 cm thick, you will have to pay around 250 rubles;
• Low moisture resistance... The material must be carefully protected from water, otherwise fungus may develop over time.

The workflow looks like this:

Illustration	Stage description
	The surface is waterproofed... Plastic wrap can be laid on the surface. If you have a wooden base, then it is better to put a vapor-permeable membrane. The material should go on the walls by 10-15 cm, the joints must be glued with tape.
	Stacked mineral wool... The material fits snugly on the surface. When cutting pieces, make them a little larger than necessary, this will allow the elements to fit tightly. Along the walls, immediately apply a damper tape to create an expansion gap.
	If you have a wooden structure, mineral wool is laid between the beams... The material can be below or flush with the sheathing. Subsequently, the surface is covered with moisture-resistant slabs and a warm floor system is already laid on them.
	Foil is laid on top of the mineral wool... The material is placed with gaps of 10 cm at the joints and the obligatory gluing of the joints with foil tape. This creates a continuous reflective surface that is suitable for both water and electric underfloor heating.

Option 4 - Penofol

This material is different from all the previous ones. Its main advantages are as follows:

• Cheapness... For a square meter of material 5 mm thick, you will pay about 50 rubles;
• Ease... 40 square meters of Penofol weighs only 8 kg. It can be laid on any structures without weighing them down;
• Efficiency... Foamed polyethylene has high thermal insulation characteristics. The reflector on the front side keeps the heat inside the room. That is, it turns out that the foil on the warm floor is combined with insulation;

Penofol - a material based on polyethylene foam with a reflector on the front side

• Choice of options... The material can have a thickness of 3 to 10 mm.

The cons are:

• It is not worth using this option as a full-fledged heat insulator in the private sector;
• It is better to combine two materials, for example, extruded polystyrene foam with a thickness of 3 cm and Penofol with a thickness of 5 mm. This is quite enough to create a very high-quality insulation;
• For laying this material, it is necessary to prepare the surface.

The workflow looks like this:

Illustration	Stage description
	Waterproofing material is laid on the floor... The film is glued at the seams and adhered to the walls to a height of about 10 cm, the excess is easily cut off later.
	Penofol is laid on top of the film... It is positioned in the same way as the film. It is important to carefully spread the material so that it lies without folds, and adjacent panels do not overlap. If you already have insulation installed and you need foil under a warm floor to create a reflective effect, then I recommend using Penofol instead. Due to the polyethylene layer, it is stronger and more durable.
	The joints are glued with a special tape... This is a metallized tape with foil, which allows not only to hold Penofol together, but also to create a continuous reflective surface throughout the room.
	The underfloor heating system is laid on top of the insulation... It all depends on the option you choose. Next, a screed device is made.

Beacons are placed on top of the structure and a screed is poured. The minimum thickness of the mortar layer above the insulation elements is 30 mm, the maximum is 60 mm. This makes the floor reliable and efficiently transfers heat from the system to the room.

Option 5 - special heat-insulating mats for warm floors

This option has the following advantages:

• Convenience... The product is a sheet of extruded polystyrene foam, in the upper part of which there is a profile with grooves or bosses for laying pipes for underfloor heating. The size of the recesses is made for a standard metal-plastic pipe with a diameter of 16 mm, so the laying work is done very quickly;

• Choice of options... The thickness of the insulating layer can be from 20 to 70 mm. The configuration of the upper part may also differ, although this is not a fundamental point;
• Fast installation process... The work takes a little time due to the fact that you quickly and efficiently lay pipes, and then you can lay tiles or lay the flooring without additional preparation. If desired, you can fill the screed, this also happens quickly and easily.

The disadvantage is the high cost, you will have to pay 300 rubles per square meter. But when you consider how simplified the process is, the costs are worth it.

The working process:

Illustration	Stage description
	The floor surface is leveled... For this, cement mortar is most often used. The fewer flaws there are, the easier it is to lay a flat floor with a minimum of time. If plywood or OSB (Oriented Strand Board) boards will be spread over the mats, then pay special attention to leveling.
	Damper tape is being prepared... The roll is unwound, a protective layer on the adhesive strip is removed from the back, you do not need to remove a lot, separate about a meter, then the film is removed as it is laid.
	The tape is glued to the walls around the perimeter... The material is gently pressed against the surface, pay particular attention to the corners. The tape is cut with an ordinary construction knife.
	The first row is laid along the wall... The photo clearly shows that at the junction there is a special ledge that tightly connects the elements and prevents them from moving, providing a reliable and even base for the underfloor heating system. Docking is done carefully so as not to damage the connection.
	Laying is done over the entire surface... If somewhere you need to cut a strip, then it can be used on the other side, thanks to the connections when using these mats, there is almost no waste left.
	The pipe is being laid... It is simply carried along the line, it is most convenient to push it in by stepping lightly with your foot.
	The pipe is laid over the entire area... Thanks to the bosses, you can easily position the warm floor correctly and will not bend the pipe. Next, the floor covering is laid or the screed is poured.

If you do not need to insulate the floor under the heating system, you can use mats without a layer of insulation. With their help, installation will take place much faster than on an unprepared surface.

Output

Using the overview as an instruction, you can easily pick up insulation under the warm floor and lay it correctly. The videos in this article will help you better understand the important points of the workflow. If something nevertheless remains unclear, ask in the comments.

When installing a warm water floor, the main task is to direct all the thermal energy into the room, therefore it is important to correctly distribute it over the entire area, and also not to let it go to the neighbors.

For this, special materials are used - insulation. There are a number of other reasons to use floor insulation:

Types of materials used for floor insulation

There are many options for insulating pipes, but all materials can be divided into:

The choice of insulation depends on:

Bulk materials and technology of their laying

The main advantage of bulk materials is their low cost and ease of use. In many respects, they are not inferior to their more expensive counterparts. The only enemy of free-flowing compounds is moisture - they are hygroscopic and lose their characteristics when wet.

Before laying pipe insulation in the form of bulk materials, you should prepare the base of the floor:

• make wooden logs, the distance between them should not exceed 800 mm;
• for each lag, a sheet of roofing material is needed;
• instead of lags, you can use a reinforcing mesh;
• the material is poured (the layer thickness should be at least 5 cm), and it is well rammed - this is a very important point, since bulk compositions shrink over time;
• then you can start laying out pipes. It is not very convenient to do this on a bulk base, since there is nothing to fix them. That is why such heaters are not in great demand.

Thermal insulation with sprayed compounds

The most common type of sprayed composition is polyurethane foam. Its advantages:

• it is quickly applied;
• fills in all the cracks;
• quickly adheres to any surface;
• creates an airtight coating.

The disadvantage of this method of insulation is that it will be difficult to do it yourself, with your own hands, since you need special equipment, which is impractical to buy for one-time use. If there is a great desire to do all the work without involving specialists, you can rent the necessary equipment.

Before applying to the concrete base of the floor, wooden forms with a width of no more than 50 cm are mounted on it. The composition is distributed using a special pneumatic gun.

At the same time, it is important to take care of the skin and respiratory system - a special suit is needed, since polyurethane foam is quite toxic.

The layer thickness should not be more than 3 cm - it increases in volume very quickly. Re-coat if necessary. The next stage is cutting off the protruding reliefs. The floor is then ready for pipe-laying. To facilitate their fastening, you can lay a reinforcing mesh with small squares on top.

Installation of underfloor heating, insulation of the base before laying pipes

How to use roll insulation

The most common roll insulation for a warm water floor is foil material. It is two-layer:

• the basis, which can be a variety of heat insulators:
  • expanded polystyrene;
  • Cork;
  • foamed polyethylene;
  • mineral wool;
• reflective coating - polypropylene metallized film or thin aluminum foil.

The thickness of the rolled polyethylene foam is from 2 to 10 mm, it can have a self-adhesive surface, which greatly facilitates the installation process.

The most popular brands in Russia:

• Folgizol;
• Penofol;
• Isoflex;
• Ecofol;
• Izolon.

Insulation for a warm water floor, based on mineral wool or fiberglass, must have a layer thickness of up to 100 mm.

The most common brands:

• Rockwool;
• Paroc;
• Knauf;
• Isover.

Roll foil insulation for pipes is very popular due to its distinctive properties:

• high reflectivity;
• moisture-proof surface;
• durability;
• good sound and heat insulation performance;
• ease of installation;
• low weight;
• low cost.

Installation technology:

Laying technology for tile insulation

Among the most common tile heaters are the following.