The thickness of the insulation in the floor of the house

The thickness of the insulation in the floor of the house The thickness of the insulation for the floor in a wooden house

The most important finishing stage for all types of premises is insulation floor surface. For some reason, most people underestimate the amount of heat loss through the floors, but a well-chosen insulation makes it possible to save up to 30% of energy on heating.

Extremely big savings are achieved when using a system of underfloor heating, which only needs to be insulated from below so that it does not warm up the ground or floors.

General information

Selecting the type of insulation that is best suited for your premises is only 50% of the business, success. It is important that the thickness of the insulation in the floor of the house is sufficient, because even the best material does not provide sufficient thermal insulation if it is laid in a thin layer.

On the other hand, a very thick insulation layer will reduce the height of the ceiling in the room and is an unjustified waste.

It is extremely important to understand that the required insulation thickness will depend on the climate conditions in your area. It becomes obvious that when using the same insulation material in typical houses in Norilsk and Sochi, completely different layer thicknesses are required. For this reason, it is important to take into account that all the tips, as well as the recommendations from the article, are given for the usual climate of central Russia, where in winter the temperature is rarely below -25 degrees. If you live in a harsher or milder climate, then it is recommended that you correct it up or down.

We suggest you consider the main types of insulation, as well as data on layer thickness when used in different types of floors.

TP - warm floor (factors) Thickness of the material for insulation
TP above the room , which is heated and the temperature is not less than +18 degrees 3 cm
TP above a heated room with an air temperature of + 10 ... + 17 degrees 5 cm
TP above the heated room, where the temperature is 0 .

.. + 10 degrees

7 cm
TP above the room that is not heated 10 cm
TP on the ground in basement / basement floor with a deepening of at least 1.5 meters 12 cm
TP on soils in the basement / basement floor, the deepening of which is from 1.5 meters and more 6 cm

Overview of materials


As a rule, this word refers to expanded polystyrene and expanded polystyrene (that is, extruded polystyrene).

In terms of thermal insulation qualities and chemical composition, such materials almost do not differ, but at the same time, penoplex has a much greater degree of bending strength, as well as resistance to crumbling, than standard foam. For this reason, recently, a large number of consumers are abandoning foam (that is, expanded polystyrene) in favor of expanded polystyrene (extruded polystyrene).

The advantage of this type of thermal insulation is its low cost, moisture resistance and ease of installation. The disadvantages include the flammability of the material, while during the combustion of polystyrene, many toxic components are emitted. Polystyrene plates are produced with a thickness of 0.

5 to 5 cm, and there is a special chamfer on the plate edges, so that when installed at the joints, no gaps are formed, and therefore "cold paths".

If the thickness of the insulation for the floor in a private house should be more than 5 cm, then 2, and sometimes 3 layers of polystyrene are laid, and each new layer must be laid relative to the previous one, so that the slab joints of the upper row fall on the center of the bottom plates. For floor insulation located directly above the ground, the foam layer should be at least 30 cm for houses with wooden floors, and 20 cm for houses with concrete self-leveling floors. You should install at least 4 layers of the thickest foam panels, with offset from each other. If there is a cool basement under the floor surface, then the foam layer can be made less by 5 cm.

For floor insulation between the floors of a private house, 15 cm of foam is enough for wooden floors, and also 10 cm for concrete floors. If you are trying to insulate the floor in an apartment building, then for all floors, except for the first, it is enough to lay one foam layer with a thickness of 5 cm.On the first floor, the thickness can be made more, up to 8-10 cm.


The thickness of the insulation in the floor of the house This version of the foam is presented in liquid form, and it has the same advantages and disadvantages as a solid option. Its plus is that it can be poured even into hard-to-reach places, and after hardening it will form a monolithic coating that has no seams.

The disadvantages include the fact that it is important to think about the method of feeding penoizol for pouring, on high floors this can become a real problem. In a large number of cases, penoizol is used in the construction of private houses, and when insulating the floor in an apartment building, it is easier to use penoplex and polystyrene foam. The thickness of the foam insulation layer should be the same as that of solid foam.

Mineral and glass wool

This is probably one of the cheapest options for thermal insulation. In addition to its low cost, cotton wool will not burn at all and have excellent vapor permeability, and therefore is ideal for insulating a wooden floor.

This is where the advantages of the material end, and the disadvantages include the fact that cotton wool has the property of accumulating moisture in itself, which causes rotting and growth of mold, and the second disadvantage will be that after a while the cotton wool will begin to crumble if the heat-insulating layer under the floor is not tightly closed, which can cause fiber particles to enter the air through the finish and irritate the respiratory tract.Also, cotton wool has a low degree of strength, easily deforms and breaks, which makes it impossible to use it under a concrete screed. For ground floor insulation, it is best to use hard slabs of mineral wool.

Despite the disadvantages, mineral wool is widely used as an insulation material, usually in a wood floor. Most manufacturers produce mineral and glass wool in sheets or rolls, and the thickness will be from 5 to 20 cm.

The sheets can be stacked in several layers at once, slightly shifting the joints so that the thermal insulation is even better.

For the use of mineral wool on the ground floor, which are placed above the ground, excellent waterproofing is required. The cotton wool will instantly absorb moisture, and then the thermal insulation properties will be lost. For this reason, it is better to use foam for thermal insulation of the first floors. If, for some reason, you still need to use mineral wool, and then its layer should be at least 40 cm.

If there is a basement under the floor surface of the first floor, then a layer of mineral wool with a thickness of 30 cm is enough.When insulating a wooden floor between the floors of a country house , the cotton layer should be at least 20 cm, and in the wooden floor of an apartment building there will be enough thickness of 10 cm.


Such material is very similar in its parameters to mineral cotton wool, but made of cellulose fibers, and therefore completely safe for health. Also, ecowool, like mineral wool, is afraid of water and can easily deform. For this reason, in most cases, it is used to insulate a wooden floor between floors.

The thickness of the insulation of the floor of the frame house will be small, since the ecowool is laid by spraying under pressure from a special tube. It turns out that the insulation can be blown under the assembled floors, and for this it is important to make only a couple of technological holes. The required thickness of the ecowool layer will correspond to the thickness of the mineral wool layer, all other things being equal.

Cork material

The main advantage of such insulation made of natural cork is the extremely high sound insulation of the coating. The high cost of the material is compensated by the fact that you can solve the problem of sound and thermal insulation at the same time.

In addition, cork insulation practically does not burn, is not afraid of moisture, is resistant to decay and is very durable, which makes it possible to use it as an insulator under a bulk floor. Due to the very beautiful factors, cork insulation is sometimes left even as a topcoat.

In this case, the top layer is covered with a special varnish composition, which will protect it and at the same time emphasize the pattern. Cork insulation is produced in sheets and rolls with a thickness of 0.3 to 20 cm.

Sheets with a maximum thickness make it possible to insulate the floor above the ground in only one layer, but at the same time it is expensive.

The price for one square meter of thick cork insulation sometimes reaches 5,200 rubles. For this reason, cork insulation on the ground floor of buildings is rarely used. The thickness of cork-type insulation on the first floor in a country house with a concrete floor should be at least 10 cm, in the floor between floors with concrete floors, one layer of 5 cm is enough, if the floors are wooden, then the layer is increased to 7 cm. In an apartment building type of cork insulation is laid in a layer of 1-3 cm, and this is quite enough for effective isolation from sounds and heat.

Polystyrene concrete

The thickness of the insulation in the floor of the house This material is relatively new for insulation, which combines in itself concrete strength and at the same time lightness, like polystyrene. The material has excellent sound and heat insulation properties, and at the same time is a high strength screed. It is ideal for thermal insulation of premises with a large area, because it is very easy to pour and level, a team of an experienced craftsman to pour up to 500 square meters of polystyrene concrete per day. Due to its low weight, polystyrene concrete will not exert a large load on the floors, unlike a simple liquid screed.

It does not need waterproofing and additional insulation.

Laminate or tiles can be laid directly on top of polystyrene concrete on a thick substrate. For the installation of soft coatings, for example, linoleum or carpet, on top of the insulation, everything is poured with a thin layer of a standard screed, with a thickness of not more than 3 cm.

For effective insulation of the first floors in country houses, 30 cm above the ground polystyrene concrete, if there is a basement under the floor, the layer can be reduced to 20 cm. 10 cm of insulation is usually poured into the floor between the floors of country houses, and 5 cm is enough for an apartment building.

Expanded clay

This material is very popular for thermal insulation and is used in wood floors or those that have a dry screed based on gypsum fiber board.

In the latter case, in addition to heat insulation, it is also a leveling material. Expanded clay is one of the cheapest materials for thermal insulation, it does not burn, is safe for health and is lightweight. Moreover, it easily absorbs water, which reduces its thermal insulation properties and greatly increases its mass. For this reason, the use of expanded clay requires reliable waterproofing. Another disadvantage is that a lot of dust rises when working with it.

In terms of the quality of thermal insulation, expanded clay is worse than most synthetic materials, and therefore it needs to be backfilled with a thicker layer, which will reduce the ceiling height in the room. The photo shows how expanded clay is used for insulation. For effective thermal insulation of the first floors of buildings from the ground, the expanded clay layer should be at least 40 cm when using a wooden floor and 30 cm when using concrete floors.Between the floors of country houses, at least 20 cm of expanded clay can be poured into the floors with wood floors and 15 cm with concrete floors. In multi-apartment buildings, a layer of 5-8 cm is enough.