Thermal insulation for underfloor heating: a comparative overview of insulation materials

Creating comfortable conditions in the living room, you need to strive for the heat during heating to spread evenly throughout the volume. As a rule, following the laws of physics, warm air rises, while the floor remains the coldest zone. Often the temperature differences at the upper and lower levels of the human stay are very significant. This creates discomfort and can cause colds. Uniform distribution of heat, constant outgoing from below, creates the necessary heat transfer. In order for the heating system to work efficiently, thermal insulation is necessary for the underfloor heating. Today we will conduct a comparative review of various thermal insulation materials.

The warm floor can be used both as additional heating of the room, and by making it the main heating system.

Why isolate the system?

And really .. why? Let's figure it out:

Natural heat loss through the coldest surface indoors to the outside or to the ground is reduced. Under ordinary conditions, the amount of heat loss reaches 20% of their total volume.
The radiated energy is evenly and rationally distributed around the perimeter of the heating. At the same time, it is not spent on heating floors and structural elements located below the heated area.
Energy is saved for additional heating, the cost of heating is reduced.
It creates additional soundproofing.
Moisture from the ground or basement is prevented from entering the room through the flooring.

Factors affecting the choice of thermal insulation

There are three main types of underfloor heating systems: water, infrared and electric. And the use of heat-insulating material directly depends on which one will be installed. In addition, the insulation under the underfloor heating is selected taking into account the loads acting on the floor covering.

The main characteristics of materials against heat loss can be considered:

high compressive strength, elasticity;
a slight degree of deformation when exposed to loads;
resistance to aggressive environments;
low thermal conductivity;
high density (for floor insulation it should be at least 25 kg / m³);
minimum moisture absorption.

The correct laying of the thermal insulation layer ensures the preservation of thermal characteristics during long-term operation

The main types of thermal insulation of underfloor heating

Cork backing

Environmentally friendly dense natural rolled insulation. The area of use is limited by the maximum height of the premises (when laying the material, the height of the floor is 3-4 cm) and the high cost of insulation.

A very important nuance - cork substrate is used only in conjunction with an additional ray-reflective layer

Polypropylene

Polypropylene in the form of extruded plates: a sound and heat insulation coating with a closed cellular structure. Not hygroscopic. Well handles. Withstands temperatures up to 130 ° C. And they also use expanded polystyrene with an overlay in the form of a polypropylene film:

Expanded polystyrene

Extruded polystyrene foam with a thickness of 50-100 mm: the best thermal insulation for a water floor heating. Strong, light, solid, inexpensive material, resistant to sharply negative and high temperatures and at the same time retaining its full properties during long-term operation.This contributes to the air filling of the cellular structure.

Expanded polystyrene is not destroyed in an aggressive environment. Does not absorb moisture and does not swell. Resistant to fungal infection, easy to assemble during installation.

Metallized Dacron Film

Such a substrate as a coating of expanded polystyrene foam provides reliable protection against floor damage during interaction with an alkaline environment of a cement-sand screed. Aluminum foil, without coating it with a high-temperature PVC film, is not used due to the instability of the foil layer to corrosion.

The substrate that prevents heat loss should be laid over the entire surface to be heated, even if heating pipes are not planned in this place. This is done in order not to violate the integrity of the surface, to ensure uniformity of the structure, to increase the reliability and strength of the coating

Please note that no matter what material is used as thermal insulation, a quality certificate must be issued for it.

The expert says: testing various substrates

The right choice of thermal insulation will not only increase the efficiency of using the "warm floor" system, but also extend the life of all its elements, provide comfort and coziness in your home.

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3 comments

yurevich
3 years ago

Hello! Why did they suddenly decide that the extruded polystyrene is “resistant to sharply negative and high temperatures and at the same time retains its full properties during long-term operation”, and most importantly, its use in residential premises? It is also known from the school chemistry program that: STIROL is a highly toxic substance. Expanded polystyrene granules were used as a component in napalm bombs to burn enemy armored vehicles
.
For particularly zealous defenders of polystyrene and polystyrene foam, we give an excerpt from the textbook on general chemistry “Glinka I.L. General Chemistry: Textbook for High Schools / Ed. A.I. Ermakova - ed. 29th, corrected - M .: Integral - Press, 2001 - 728 s. ” - “... polystyrene quickly“ ages ”, has a tendency to crack, is characterized by low thermal resistance, low strength and poor gas resistance ...” (p. 606)
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Yaroslav
5 years ago

I agree with the author of the article that extruded polystyrene foam is the best thermal insulation for a warm floor system. In addition, Russia now has several productions of this material. You can choose almost any brand - Technoplex, Penoplex, URSA XPS - the quality of the material will be comparable. But I do not agree with the author that the material is resistant to high temperatures and hostile environment. The upper temperature threshold of the material is “+ 75C”. Material is destroyed by exposure to gasoline, kerosene and other solvents.
And an important note about strength - the material is very durable, but only if the load is distributed. That is, if extruded polystyrene foam is laid on a flat surface, and the load is distributed on top with an OSB plate, for example, then cars can ride on the surface and this insulation will withstand this load. But if during pouring with a cement mixture of extrusion plates it gets into the joints, then subsequently hardened cement mortar will lead to deformation of the plates.
And yet - I would not consider a cork substrate and a metallized mylar film as an alternative to extruded polystyrene foam. As additional thermal insulation layers - a great option. Especially foil foamed polyethylene or metallized polyester film with its own reflective effect.
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Nikolay
6 years ago

Soon the colds will come, so it is time to warm the floors) In our apartment, the walls and the floor in the winter are usually very cold. I think to make a warm floor, or at least make it warmly insulated, so to speak. Polypropylene is the best suited for this, because it not only insulates heat, but also has soundproofing properties.
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