What should be the thickness of the insulation for the floor in a wooden house

What should be the thickness of the insulation for the floor in a wooden house Do-it-yourself floor insulation in a wooden house and calculation

Wooden buildings are considered to be thermally efficient because the wood does not conduct much heat. But in reality everything is not so. The lumber will begin to dry out, crack, and because of this, the cold will penetrate inside.

Floors are usually made using frame technology, which is why it is required to lay an insulating layer inside them. The thickness of the floor insulation in a wooden house will fully depend on the selected thermal insulator.

Basic information

Thickness is usually chosen depending on the regional climate. Only one indicator will be provided for the northern republics, and another for the southern ones. In addition, the thicker the insulation, the better the heat will be retained, and then less energy will be spent on heating. Also, insulation saves from the heat, and insulation is an excellent sound insulator. The thickness will change depending on the type of floor and its location.

The floor on the first floor is the coldest, and besides, if the suburban housing is installed on piles, and is also blown from below. But it can be ground, and if the base is of the tape type, and concrete if it is slab.

The floors between the floors are heated on both sides, and the insulation is used only as sound insulation. the attic floor will also become the floor. It must be insulated without fail, and even more so if the attic is not heated.

In the opposite case, it will go out into the street, and in addition, condensation forms on the ceiling. All materials have their own coefficient of thermal conductivity. This parameter is of primary importance when determining the insulation thickness. The efficiency will also depend on tightness, and the higher this indicator, the more difficult it is for the insulator to retain heat. For example, 12 cm of polystyrene will retain heat as effectively as 2.

1 meters of solid red brick.


Polymer materials

It is extremely important to study certain types of insulation and compare them with each other.

Thickness of expanded polystyrene

This material is habitually called foam, but this is not always true, because foam is a large group of foam-type polymeric materials. Such plates are the most effective types of materials:

  1. Suspended, pressless - it is labeled as PSB. The price per square meter with a thickness of 2 cm is only 45 rubles.

    The structure is glued together with large granules. When split, it crumbles immediately. This expanded polystyrene material cannot be dense, it cannot be screed, it is very flammable, and can also be easily processed into dust due to rodents. It can be used as a heater for a floor in a house made of wood, but a low degree of quality will not give the desired result.

  2. Press foam polystyrene (PS) has closed cells.

    During production, certain brands of latex-type PVC and blowing agents are added. They keep warm well, have a denser and stronger structure, and are not afraid of mold. But not this material is mostly used for floor insulation, but the third type.

  3. EPS is obtained by extruding molten material through holes with some shape. It has a dense structure, all cells are covered, which means that the material will not absorb water, it transfers loads of a mechanical type - it can be used for plastering and equipping a concrete screed.

Each type of material has a different density, thermal conductivity, but in general, insulators are effective. The material can be bought with different thicknesses - from 0.5 to 10 cm. If you need to take 10 cm of material for insulation, you need to take a plate that is not comparable in thickness, but a couple of layers of 5 cm each, and overlap them. This approach eliminates the cold bridges that form at the seams.

Individual boards have profiled edges for easy joining. Heat losses will also be reduced.

Good advice! When installing expanded polystyrene plates, the seams must be additionally coated with polyurethane foam. By the way, this material can also be attributed to foam.

Coefficient of thermal conductivity of non-pressed expanded polystyrene 0.

05 W / m O C. The extrusion index will be much lower, that is, 0. 04 at a density of 40 kg per cubic meter, despite the high density index.

What thickness to choose Penoplex

The thickness of the insulation for the floor of a wooden house should be oriented according to certain principles. Most consider penoplex as a separate material for thermal insulation, and we are talking about a specific manufacturer of EPS.

The fact is that this brand is well advertised.

Polyurethane foam

What should be the thickness of the insulation for the floor in a wooden house Yes a separate category of insulation materials is sprayed materials. We are talking about penoizol and polyurethane foam. Both are recognized as very effective, and the advantage over analogues is obtained due to application. So, the coating will turn out to be monolithic, which will help to get rid of cold bridges.

Such insulation is required 2 times less than expanded polystyrene. Density can also vary.

It is adjusted during installation, due to the selection of the composition. A liquid material consists of a pair of components that will be mixed together when sprayed. Companies that deal with this insulation may use poor quality raw materials.

Durability and thermal conductivity depend on this. It is considered the most effective known to man today. Its use helps to make walls thinner. Installation requires the use of specialized expensive equipment.

The floor will not be insulated with sprayed polymers on its own.

The procedure is carried out quickly, and specialists will be able to do everything within a couple of days, everything will depend on the size of the object.

Where foam is used in a wooden house

Foamed plastic includes both expanded polyethylene and expanded PVC. Thermal insulators are all effective, but they are rarely used for insulating wood houses.

  • Most of the insulation materials are combustible, which in combination with wood will give a dangerous combination.
  • Polymers do not allow steam to pass through - on the one hand, this is great, walls and material are not saturated with moisture, but this is the main feature of a wooden house, and the walls must breathe, thereby creating a pleasant microclimate for humans.

The only place that Styrofoam is good for a wooden house is the floor on the ground floor, and especially if it goes along the ground. High density extruded polystyrene foam boards will be an excellent base for cement screed. Foamed and foil-clad polyethylene are relevant for the underfloor heating system, and with a small insulator thickness, heat will be effectively reflected inward. Expanded polystyrene PSB is also unsuitable because mice can settle in it. This is extremely dangerous for frame-type buildings, because with a thinning of the thermal insulator layer, the house will become cold.

Mineral insulation

It is safe and profitable to insulate wooden houses with mineral wool. If we compare mineral wool with expanded polystyrene, with a comparable degree of thermal conductivity density (or rather, the coefficient) of the 1st will be about half as high. Where 5 cm of PP is sufficient, 7.5 cm of rock wool can replace it. There are several types of mineral wool that have different characteristics.

Products from various manufacturing companies may vary significantly in quality. Material types:

  1. Glass wool is the most readily available material that contains harmful formaldehydes. It is very dusty, which means that it is practically not used for residential premises.
  2. Shpakovata is also a material harmful to health due to phenol-formaldehydes. There are models of the composite type, which contain up to 20% wool.

    Such material keeps heat perfectly, and it can be used for the floor of an unheated attic.

  3. Stone wool can be of several types - they have the same disadvantages as other types, but to a lesser extent. Such materials do not burn even when heated to +1100 degrees.

Such material costs from 110 to 170 rubles per square with a thickness of 5 cm. Min.

cotton wool is vapor-permeable, and this is considered an advantage and a disadvantage. They lose their thermal efficiency when wet from steam, and glass wool suffers the most. This can be omitted in the ceilings between floors when all rooms are heated. The steam will simply come out through, the moisture will go away, and the layer of insulation dries up. Cotton wool with a density of more than 1.

5 centners per cubic meter is used as a base for a screed, but it is better to use extruded polystyrene foam.For insulation of the frame floors, you can use cotton wool with a minimum density, which makes the insulation more effective.

Foil insulation

There are a lot of manufacturers that produce heaters. Someone will develop unique technologies due to which the products will be more energy efficient. For this reason, it is not always useful to rely on average parameters.

It is necessary to highlight products that are supplemented with a layer of aluminum foil on the other side. Aluminum will reflect heat, and if a thin layer makes it possible to increase the efficiency of the entire "cake" and reduce its thickness. This supplement has certain polymer insulators and min. cotton wool. The use of a foil layer is extremely effective when installing warm floors.

Energy reflection prevents the ground or the street from heating up. Also, materials from a structural point of view can be supplemented with plates and substrates of rigid materials to simplify installation. Substrates make the resistance of materials to loads higher, and it is profitable to purchase them if the insulation process is from the bottom, where the lower floor or basement is. Dense materials, such as extruded polystyrene foam, can become the foundation in wooden houses. The combination of expanded polystyrene and mineral wool reduces the entire thickness of the floor, and also makes it as protected as possible.

Other materials

To insulate the floor in a wooden house with their own hands, they are often interested in what the expanded clay layer should be. This will indicate a lack of understanding of the purpose of certain building materials.

Expanded clay

What should be the thickness of the insulation for the floor in a wooden house This material is loose type after a while it shrinks, and its height will become smaller. The coefficient of thermal conductivity at a minimum degree of density of 2 centners per cubic meter is 0. 1 W / m O C, and this is sufficient according to GOST for the insulation of the external structures of a single-family residential building.

But it is much worse by 30% than mineral wool. Expanded clay will significantly load frame ceilings, and it can be used for a wooden house only on the floor, made on the ground, as a base for a screed.


There is another material that can be identified as a controversial category, that is, ecowool. It is free-flowing and made by recycling. The thermal efficiency coefficient is only slightly inferior to penoizol, but only when wet spraying is used.

But it rots, does not burn, does not attract rodents and is inexpensive, and the average price of a kilogram is 76 rubles. If you just pour in ecowool, then it will not be able to effectively retain heat.

If it is sprayed, the moisture in the material will begin to evaporate within 2 months, which can lead to the process of decay of wood structures. So far, Russia has not developed a single standard for this material. As a result, manufacturers sell whatever they want.

This is not about any security. Even the final price will be high.For high quality insulation in a wooden house, natural insulation can be produced, which is made from coconut, linen, wool and various trees. They are very effective, environmentally friendly, but extremely expensive.

Calculation of thickness

The norms are different for the particular climate.

Usually, three values ​​are specified for all regions, and the second is for overlaps. The temperature degree of resistance of the material will be calculated as follows - R = h / λ, with h being the thickness of the material and λ being the temperature coefficient. It turns out that by representing the values, you can derive a formula with a thickness h = R * λ. But the floor is not made of insulation. To obtain this value, it is required to calculate the resistance to heat loss of all installed materials, subtract it from the norm, and leave the rest for the insulation material.

The most simple example. From below, the overlap is hemmed with a board with a thickness of 2.5 cm, and from above it is 3 cm. As a result, it turns out 5.5 cm of wood.

Refine the wood species, find the heat loss factor and calculate the R value der .

( 1 grade, average 5 of 5 )