Table of thermal conductivity of building materials: coefficients

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Any construction, regardless of its size, always begins with the development of a project. Its goal is to design not only the appearance of the future structure, but also to calculate the main thermal characteristics. After all, the main task of construction is the construction of strong, durable buildings capable of maintaining a healthy and comfortable microclimate, without unnecessary heating costs. The table of thermal conductivity of building materials: coefficients will undoubtedly help in choosing the raw materials used for the construction of a building.

The heat in the house directly depends on the thermal conductivity coefficient of building materials

Table of thermal conductivity of thermal insulation materials

To make it easier to keep your house warm in winter and cool in summer, the thermal conductivity of walls, floors and roofs must be at least a certain figure, which is calculated for each region.
The composition of the “pie” of walls, floor and ceiling, the thickness of the materials are taken into account so that the total figure is no less (or better yet, at least a little more) recommended for your region. Heat transfer coefficient of modern building materials for enclosing structures

When choosing materials, it is necessary to take into account that some of them (not all) conduct heat much better in conditions of high humidity. If such a situation may occur for a long period of time during operation, the thermal conductivity for this condition is used in the calculations. The thermal conductivity coefficients of the main materials used for insulation are given in the table.

Some of the information is taken from standards that prescribe the characteristics of certain materials (SNiP 23-02-2003, SP 50.13330.2012, SNiP II-3-79* (Appendix 2)). Those materials that are not specified in the standards are found on the manufacturers’ websites

Since there are no standards, they can differ significantly from different manufacturers, so when purchasing, pay attention to the characteristics of each material purchased

Thermal conductivity indicators for finished buildings. Types of insulation

When creating a project, you need to consider all ways of heat leakage. It can come out through walls and roofs, as well as through floors and doors. If you carry out design calculations incorrectly, you will have to be content only with the thermal energy received from heating devices. Buildings built from standard raw materials: stone, brick or concrete need to be additionally insulated.

Additional thermal insulation is carried out in frame buildings. At the same time, a wooden frame gives rigidity to the structure, and insulating material is laid in the space between the posts. In buildings made of brick and cinder blocks, insulation is done from the outside of the structure.

When choosing insulation materials, you need to pay attention to factors such as humidity levels, the influence of elevated temperatures and the type of structure. Consider certain parameters of insulating structures:

• the thermal conductivity indicator affects the quality of the heat-insulating process;
• moisture absorption is of great importance when insulating external elements;
• thickness affects the reliability of insulation. Thin insulation helps preserve the usable area of ​​the room;
• Flammability is important. High-quality raw materials have the ability to self-extinguish;
• thermal stability reflects the ability to withstand temperature changes;
• environmental friendliness and safety;
• Sound insulation protects against noise.

Characteristics of different types of insulation
The following types of insulation are used:

mineral wool is fire resistant and environmentally friendly. Important characteristics include low thermal conductivity;

This material is one of the most affordable and simplest options.

• polystyrene foam is a lightweight material with good insulating properties. It is easy to install and is moisture resistant. Recommended for use in non-residential buildings;
• basalt wool, unlike mineral wool, has better resistance to moisture;
• Penoplex is resistant to humidity, elevated temperatures and fire. It has excellent thermal conductivity, is easy to install and durable;

Penoplex is characterized by a porous structure

• polyurethane foam is known for such qualities as non-flammability, good water-repellent properties and high fire resistance;
• Extruded polystyrene foam undergoes additional processing during production. Has a uniform structure;

This option comes in different thicknesses.
Penofol is a multi-layer insulating layer. The composition contains foamed polyethylene. The surface of the plate is covered with foil to provide reflection.

Bulk types of raw materials can be used for thermal insulation. These are paper granules or perlite. They are resistant to moisture and fire. And among organic varieties, you can consider wood fiber, flax or cork.

When choosing, pay special attention to such indicators as environmental friendliness and fire safety

What you need to know about the thermal conductivity of foam plastic

The ability of a material to transfer heat, conduct or retain heat flows is usually assessed by the thermal conductivity coefficient. If you look at its dimension - W/m∙C o , it becomes clear that this is a specific value, that is, determined for the following conditions:

• The absence of moisture on the surface of the slab, that is, the thermal conductivity coefficient of polystyrene foam from the reference book, is a value determined in ideally dry conditions, which practically do not exist in nature, except perhaps in the desert or Antarctica;
• The value of the thermal conductivity coefficient is given for a foam thickness of 1 meter, which is very convenient for theory, but somehow not impressive for practical calculations;
• The results of measuring thermal conductivity and heat transfer were carried out for normal conditions at a temperature of 20 o C.

According to a simplified method, when calculating the thermal resistance of a layer of foam insulation, you need to multiply the thickness of the material by the thermal conductivity coefficient, then multiply or divide by several coefficients used to take into account the actual operating conditions of the thermal insulation. For example, strong watering of the material, or the presence of cold bridges, or the method of installation on the walls of the building.

How the thermal conductivity of polystyrene foam differs from other materials can be seen in the comparison table below.

It's actually not that simple. To determine the thermal conductivity value, you can create it yourself or use a ready-made program for calculating insulation parameters. For a small object this is usually done. A private owner or self-builder may not be interested in the thermal conductivity of the walls at all, but rather lay insulation from foam plastic material with a margin of 50 mm, which will be quite enough for the harshest winters.

Large construction companies that insulate walls covering an area of ​​tens of thousands of square meters prefer to act more pragmatically. The calculation of the insulation thickness is used to draw up an estimate, and the actual thermal conductivity values ​​are obtained on a full-scale object. To do this, glue several sheets of foam plastic of different thicknesses onto a section of the wall and measure the actual thermal resistance of the insulation. As a result, it is possible to calculate the optimal thickness of the foam with an accuracy of several millimeters; instead of approximately 100 mm of insulation, you can lay the exact value of 80 mm and save a considerable amount of money.

How beneficial the use of polystyrene foam is in comparison with standard materials can be assessed from the diagram below.

Area of ​​application of mineral wool

Cotton wool for insulation has a low thermal conductivity coefficient, so it is used in various construction and industrial fields

It is important to emphasize that it is an almost irreplaceable heat insulator when it comes to working with hot enclosing elements, because it has a low level of flammability

In addition, it is now actively used in insulating building facades, as well as for creating internal insulation in concrete and reinforced concrete buildings. Mineral wool is used for arranging drainage and heating systems. In the last few years, due to its availability, this material has also begun to be used for the construction of small baths. Comparative characteristics of insulation materials

How to calculate wall thickness

In order for the house to be warm in winter and cool in summer, it is necessary that the enclosing structures (walls, floor, ceiling/roof) must have a certain thermal resistance. This value is different for each region. It depends on the average temperatures and humidity in a particular area.

Thermal resistance of enclosing structures for regions of Russia

In order for heating bills not to be too high, it is necessary to select building materials and their thickness so that their total thermal resistance is not less than that indicated in the table.

Calculation of wall thickness, insulation thickness, finishing layers

Modern construction is characterized by a situation where the wall has several layers. In addition to the supporting structure, there is insulation and finishing materials. Each layer has its own thickness. How to determine the thickness of insulation? The calculation is simple. Based on the formula:

Formula for calculating thermal resistance

R—thermal resistance;

p—layer thickness in meters;

k is the thermal conductivity coefficient.

First you need to decide on the materials that you will use during construction. Moreover, you need to know exactly what type of wall material, insulation, finishing, etc. will be. After all, each of them makes its contribution to thermal insulation, and the thermal conductivity of building materials is taken into account in the calculation.

First, the thermal resistance of the structural material (from which the wall, ceiling, etc. will be built) is calculated, then the thickness of the selected insulation is selected based on the “residual” principle. You can also take into account the thermal insulation characteristics of finishing materials, but usually they are a plus to the main ones. This is how a certain reserve is laid down “just in case.” This reserve allows you to save on heating, which subsequently has a positive effect on the budget.

An example of calculating the thickness of insulation

Let's look at it with an example. We are going to build a brick wall - one and a half bricks long, and we will insulate it with mineral wool. According to the table, the thermal resistance of walls for the region should be at least 3.5. The calculation for this situation is given below.

1. First, let's calculate the thermal resistance of a brick wall. One and a half bricks is 38 cm or 0.38 meters, the thermal conductivity coefficient of brickwork is 0.56. We calculate using the above formula: 0.38/0.56 = 0.68. A wall of 1.5 bricks has this thermal resistance.
2. We subtract this value from the total thermal resistance for the region: 3.5-0.68 = 2.82.
   This value must be “added” with thermal insulation and finishing materials. All enclosing structures will have to be calculated
3. We calculate the thickness of mineral wool. Its thermal conductivity coefficient is 0.045. The thickness of the layer will be: 2.82 * 0.045 = 0.1269 m or 12.7 cm. That is, to ensure the required level of insulation, the thickness of the mineral wool layer must be at least 13 cm.

If the budget is limited, you can take 10 cm of mineral wool, and the missing amount will be covered with finishing materials. They will be inside and outside. But, if you want your heating bills to be minimal, it is better to use the finishing as a “plus” to the calculated value. This is your reserve during the lowest temperatures, since thermal resistance standards for enclosing structures are calculated based on the average temperature over several years, and winters can be abnormally cold

Therefore, the thermal conductivity of building materials used for finishing is simply not taken into account

How to choose materials for thermal insulation at home

Note that there is no universal best insulation. For each individual case, you need to select the appropriate material.

To figure out how to choose thermal insulation for your home, consider its types:

Mineral wool. Easy to install and insulates well. But it cannot withstand pressure and is not suitable for wet areas. Depending on the type of raw material from which it is produced, there are stone (basalt), glass and slag. Basalt-based home insulation is completely non-flammable and does not chip. Glass wool has two main advantages: it is non-flammable and very cheap. But working with it is not at all comfortable, since the material is itchy and causes allergies. Slag wool is only suitable for attics and non-residential buildings as it is not environmentally friendly.

• Foam glass
  . Available in blocks, durable. This is a new and expensive material.
• Styrofoam
  . Its popularity is determined by its low price. Does not absorb moisture, is partially vapor permeable, does not rot, does not mold. Durable. But it has low strength. Rodents love to build nests in polystyrene foam. The optimal density is 25 kg/m2.
• Expanded polystyrene
  . This insulation is made from the same material as foam, but it is modern and more durable. Used for walls, foundations, flat roofs. At the same time it provides moisture insulation. Currently, polystyrene foam is the leader in the thermal insulation rating.
• Sheet polyurethane foam
  . Its properties are similar to expanded polystyrene, but it is breathable and easily absorbs water.
• Foam
  . It is made on the basis of polyurethane foam or penoizol. Good for insulating walls outside. Covers the surface completely, without cold bridges, due to which the walls after treatment have minimal thermal conductivity. But insulation in this way is expensive - the technology requires the use of special equipment and qualified personnel.
• Foamed polyethylene foam
  . There is PPE or NPE. Take only PPE - it is more durable. It is used for insulating pipes, internal walls, and floors. There are options with reflective foil film.

Important characteristics:

• Thermal conductivity
  . Shows how much heat in watts the material will lose. The lower the coefficient, the better. The average value is 0.038–0.046 W/mK.
• Vapor permeability
  . The ability of the material to breathe, allowing moisture vapor to pass through. Quality required for timber structures.
• Shrinkage
  . It is desirable that it be minimal or absent. Otherwise, over time, under the influence of its own mass, the thermal insulation will decrease in volume and deteriorate its properties.
• Hygroscopicity
  . Determines the ability of a material to absorb water vapor. Materials with high hygroscopicity are less effective because liquid increases thermal conductivity. Also, such insulation cannot be used in damp places.

• Operating temperature
  . Correctly selected insulation for this parameter will serve with high quality and for a long time. For example, in the northern regions frosts can reach -40 and -50 °C. In summer, metal roofs heat up to 80–90 °C.
• Flammability
  . Insulation materials are flammable and non-flammable. Indoors it is better to use non-flammable or low-flammable ones. Also, non-combustible insulation materials should be used in fire hazardous areas.
• Environmental friendliness
  . Important for use in residential areas. Environmentally friendly materials do not emit harmful substances.
• Firms
  . There are a lot of manufacturers of high-quality thermal insulation. Among the brands that have proven their effectiveness are the following: Rockwool, Isoroc, Energoflex, Penoplex, Akterm Nord, TechnoNIKOL, URSA, Hotrock, KNAUF, Isover, Ecostroy.

Table of thermal conductivity of materials on Pa-Pen

Sequencing

First of all, you need to choose the building materials that you will use to build the house. After this, we calculate the thermal resistance of the wall according to the scheme described above. The obtained values ​​should be compared with the data in the tables. If they match or are higher, good.

If the value is lower than in the table, then you need to increase the thickness of the insulation or wall and perform the calculation again. If the structure contains an air gap that is ventilated with outside air, then the layers located between the air chamber and the street should not be taken into account.

Main characteristics of insulation

Let us first provide the characteristics of the most popular thermal insulation materials, which you should first pay attention to when choosing. Comparison of thermal conductivity insulation should be made only on the basis of the purpose of the materials and room conditions (humidity, presence of open fire, etc.). We have further arranged in order of importance the main characteristics of insulation

We have further arranged in order of importance the main characteristics of insulation.

Comparison of building materials

Thermal conductivity. The lower this indicator, the less thermal insulation layer is required, which means that insulation costs will also be reduced.

Moisture permeability. The lower permeability of the material to moisture vapor reduces the negative impact on the insulation during operation.

Fire safety. Thermal insulation should not burn or emit toxic gases, especially when insulating a boiler room or chimney.

Durability. The longer the service life, the cheaper it will cost you during operation, since it will not require frequent replacement.

Environmentally friendly. The material must be safe for humans and the environment.

Ideal warm home

The comfort and economy of living in it depends on the design features of the building and the materials used in its construction. Comfort lies in creating an optimal microclimate inside, regardless of external weather conditions and ambient temperature. If the materials are selected correctly, and the boiler equipment and ventilation are installed according to the standards, then such a house will have a comfortable, cool temperature in summer and warmth in winter. In addition, if all materials used in construction have good thermal insulation properties, then energy costs for space heating will be minimal.

Table of thermal conductivity of materials on Cl...

Acceptable values ​​depending on region

The minimum permissible value of heat conductivity for various regions is indicated in the table:

Each material has its own heat conductivity index. The higher it is, the more heat this material transmits through itself.

Thermal conductivity coefficient of building materials - tables

The thermal insulation properties of materials are perfectly demonstrated by summary tables that present standard indicators.

Table of heat transfer coefficients of materials. Part 1

Heat conductivity of materials. Part 2 Table of thermal conductivity of insulating materials for concrete floors

But these tables of thermal conductivity of materials and insulation materials do not take into account all the values. Let's take a closer look at the heat transfer of basic building materials.

Brick thermal conductivity table

As we have already seen, brick is not the “warmest” wall material. In terms of thermal efficiency, it lags behind wood, foam concrete and expanded clay. But with proper insulation, it makes for cozy and warm homes.

Comparison of thermal conductivity of building materials by thickness (brick and foam concrete)

But not all types of brick have the same thermal conductivity coefficient (λ). For example, for clinker it is the largest - 0.4−0.9 W/(m K). Therefore, it is impractical to build something out of it. Most often it is used for road work and laying floors in technical buildings. The smallest coefficient of this characteristic is for the so-called thermal ceramics - only 0.11 W/(m K). But such a product is also very fragile, which minimizes its scope of application.

A good match between strength and thermal efficiency of sand-lime bricks. But masonry made from them also needs additional insulation, and depending on the region of construction, perhaps also thickening the wall. Below is a comparative table of heat conductivity values ​​for different types of bricks.

Thermal conductivity of different types of bricks

Table of thermal conductivity of metals

The thermal conductivity of metals is no less important in construction, for example, when choosing heating radiators. Also, such values ​​cannot be avoided when welding critical structures, producing semiconductors and various insulators. Below are comparative tables of the thermal conductivity of various metals.

Thermal efficiency of different types of metals. Part 1 Thermal efficiency of different types of metals. Part 2 Thermal efficiency of different types of metals. Part 3

Wood thermal conductivity table

Wood in construction is unofficially classified as an elite material for building houses. And this is not only because of environmental friendliness and high cost. Wood has the lowest thermal conductivity coefficients. Moreover, such values ​​directly depend on the breed. The lowest coefficient among building species is cedar (only 0.095 W/(m∙C)) and cork. Building houses from the latter is very expensive and problematic. But cork for flooring is valued because of its low heat conductivity and good sound insulation qualities. Below are tables of thermal conductivity and strength of various rocks.

Heat conductivity of woodStrength of different types of wood

Table of thermal conductivity of concrete

Concrete in its various variations is the most common building material today, although it is not the “warmest”. In construction, a distinction is made between structural and thermal insulating concrete. The former are used to build foundations and critical components of buildings with subsequent insulation, while the latter are used to build walls. Depending on the region, either additional insulation is applied to them or not.

Comparative table of thermal insulation concrete and thermal conductivity of various wall materials

Aerated concrete is considered the most “warm” and durable. Although this is not entirely true. If you compare the structure of foam blocks and aerated concrete, you can see significant differences. In the first, the pores are closed, while in gas silicates, most of them are open, as if “torn.” This is why in windy weather an uninsulated house made of aerated blocks is very cold. The same reason makes such lightweight concrete more susceptible to moisture.

What is the thermal conductivity coefficient of the air gap?

In construction, windproof air layers are often used, which only increase the heat conductivity of the entire building. Also, such vents are necessary to remove moisture outside.

Particular attention is paid to the design of such layers in foam concrete buildings for various purposes. Such layers also have their own thermal conductivity coefficient depending on their thickness

Table of heat conductivity of air layers

Comparison of insulation by type and properties

Mineral wool has low thermal conductivity. This quality gives this material an advantage over most modern insulation materials. The TechnoNikol company offers a varied range of mineral wool for thermal insulation and finishing of premises.

Rocklight slabs

Rocklight is a thermal insulation board made of stone wool for heat and sound insulation coating. This type of slab is used in private housing construction. Ideal for thermal insulation of roofs and other structures. It is one of the best thermal insulation materials.

The main advantages of Rocklight

1. Correctly chosen insulation can last a very long time in operation.
2. Simple installation (installation of thermal insulation with Rocklight slabs is very convenient due to their light weight. The slabs are produced in packs, sheets measuring 1200 * 60 * 50 mm. They are convenient to install in frames, combine with each other and use for insulation in several layers)
3. Fire safety (non-flammable material)
4. No influence of moisture on the slabs (cotton wool practically does not absorb moisture)
5. Good thermal insulation properties (mineral wool from which the slabs are made provides excellent resistance to cold. Thermal conductivity corresponds to cold climates and is 0.036 W/m.

"Technoblock" slabs

Insulator in the form of mineral wool slabs. Medium density material from 40 to 50 kg/m3. Therefore, this type does not withstand high loads and is used in the construction of low-rise buildings. It is used in finishing the facades of houses and for siding. You can use insulation by laying it in two layers.

Advantages of Technoblock:

• Sound absorption (due to the plates, noise penetration is reduced)
• Vapor permeability (air circulation)
• Moisture resistance
• Long service life (manufacturer provides a guarantee of up to 80 years)
• Low thermal conductivity. Is no more than 0.034 W/m.
• Thanks to its high thermal insulation properties, the insulator maintains a comfortable microclimate in residential premises, which allows you to save on heating costs.

"Technoruf"

Non-flammable stone wool slabs to create a thermal insulation layer. Tekhnoruf products are resistant to deformation, therefore they retain their qualities perfectly. The boards are resistant to moisture, therefore preventing the appearance of dampness indoors.

Purpose:

1. Wall
2. Floor
3. Attics
4. Attic floors

The products are formed from closely intertwined fine fibers of cotton wool origin. They have a high level of sound insulation, which helps reduce airborne and impact noise levels.

Quality:

1. Durability (the boards consist of vertical and horizontal fibers, which makes them durable and increases their service life)
2. Resistance of insulation to fire (plates made of non-combustible material, thanks to this they can be used in premises for any purpose)
3. Light weight of the slabs (this quality allows installation quickly and on any surface).
4. Low thermal conductivity 0.041 W/m

"Technovent"

"Technovent" - new generation insulation materials based on mineral basalt wool.

The assortment includes 3 lines of material:

1. "Standard";
2. "Optima";
3. "Prof."

The difference between these materials is:

• material hardness;
• density.

All three types of material are intended for insulation of ventilated facade structures, and are optimized for creating single-layer protective thermal insulation.

High performance in:

• fireproof;
• environmental cleanliness;
• ease of installation.

"Technoflor"

"Technoflor" is a material that is designed for thermal and sound insulation of floors. Rigid mineral wool panels are used for surfaces subject to heavy loads. Energy-saving material that is not subject to temperature changes. Provides 100% sound insulation.

Fire-resistant, does not rot and is not susceptible to negative environmental influences. Indispensable for insulating sports-type floors that are exposed to heavy mechanical loads. Used for insulation of floating floors, for heated floors with the method of laying wool on the ground or installing wool on a concrete base.

The Technoflor product is produced in sheets with dimensions: 1000x500x40mm and 1200x600x200mm. The service life of this product from the TechnoNikol series reaches 80 years.

"Technoacoustic"

Environmentally friendly material intended for use as sound insulation:

• used for interior and exterior work;
• to absorb noise;
• frame partitions;
• suspended ceilings;
• floors.

It has the ability to retain and absorb noise up to 60 dB. In this regard, it provides a high level of acoustic protection of walls.

"Heat roll"

“Teploroll” is a new generation of rolled thermal insulation. Available in the form of mats. The mats are highly durable. Provide high thermal insulation and sound insulation qualities. Used in insulation and insulation of roofs, partitions and ceilings. Widely used in the construction of private houses.

Peculiarities:

• the material does not burn or rot;
• has a low level of thermal conductivity;
• resistant to the formation of mold and mildew, does not collapse under high humidity;
• not subject to destruction;
• non-toxic and absolutely safe for human health.

Thermal insulation has a good level of noise suppression. Easy to install due to its short length.

"Techno T"

These are rigid stone wool slabs that are used in civil and industrial construction for thermal insulation. Due to this, this material has limitations in use. Withstands a wide temperature range from −180 C to +750 C.

This is a feature of the material and the main difference from conventional building insulation. Allows installation of thermal insulation of air ducts, gas ducts, industrial furnaces.

Plates can be produced treated with aluminum foil or fiberglass on one side. Foil insulation provides a number of advantages. The foil coating of the insulation does not allow moisture to get under the coating, thereby ensuring moisture penetration. Foil does not allow cold air to pass through and does not release heat. Thanks to the high heat transfer coefficient, it can withstand temperature changes. Capable of reflecting ultraviolet rays.

Why is Penoplex in demand among consumers?

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Penoplex is a highly effective new generation material. It is universal for home insulation. Unlike mineral wool, expanded polystyrene is not afraid of moisture. Thanks to this, it does not require additional waterproofing. Provides high thermal protection, works like a thermos. Does not burn. During installation, it can be mounted directly on the ground surface. Dense insulator, tolerates mechanical loads well, has low vapor permeability.

Recommendations for use:

• To insulate the floor and basement of a house (if it has non-residential status);
• Ideal for working on flat roofs;
• Insulation of septic tanks and wells;
• Thermal insulation of facades and internal walls.

Penoplex does not allow moisture to pass through, so it is not suitable for ventilated facades.

Material advantages

• Low thermal conductivity;
• Minimum water absorption;
• High compressive strength;
• Durability;
• Frost resistance;
• Not subject to rotting, plastic material.

If individual construction is planned

When building a house, it is important to take into account the technical characteristics of all components (wall material, masonry mortar, future insulation, waterproofing and steam-removing films, finishing). To understand which walls will best retain heat, you need to analyze the thermal conductivity coefficient of not only the wall material, but also the mortar, as can be seen from the table below: To understand which walls will best retain heat, you need to analyze the thermal conductivity coefficient of not only the wall material, but also the mortar, as can be seen from the table below:

To understand which walls will best retain heat, you need to analyze the thermal conductivity coefficient of not only the wall material, but also the mortar, as can be seen from the table below:

Important. From the data given in the table it can be seen that each building material has a fairly large spread in the thermal conductivity coefficient.

This is due to several reasons:

• Density. All insulation materials are produced or installed (penoizol, ecowool) of varying densities. The lower the density (more air is present in the insulating structure), the lower the heat conductivity. And, conversely, for very dense insulation materials this coefficient is higher.
• The substance from which it is produced (base). For example, brick can be silicate, ceramic, or clay. The thermal conductivity coefficient also depends on this.
• Number of voids. This applies to bricks (hollow and solid) and thermal insulation. Air is the worst conductor of heat. Its thermal conductivity coefficient is 0.026. The more voids, the lower this figure.

Mortar conducts heat well, so it is recommended to insulate any walls.

Efficiency of multilayer structures

Density and thermal conductivity

Currently, there is no building material whose high load-bearing capacity would be combined with low thermal conductivity. The construction of buildings based on the principle of multilayer structures allows:

• comply with design standards for construction and energy conservation;
• keep the dimensions of enclosing structures within reason;
• reduce material costs for the construction of the facility and its maintenance;
• achieve durability and maintainability (for example, when replacing one sheet of mineral wool).

The combination of structural and thermal insulation materials ensures strength and reduces thermal energy loss to an optimal level. Therefore, when designing walls, calculations take into account each layer of the future enclosing structure.

It is also important to take into account the density when building a house and when insulating it. The density of a substance is a factor influencing its thermal conductivity and ability to retain the main heat insulator - air

The density of a substance is a factor that affects its thermal conductivity and ability to retain the main heat insulator - air.

Calculation of wall thickness and insulation

Calculation of wall thickness depends on the following indicators:

• density;
• calculated thermal conductivity;
• heat transfer resistance coefficient.

According to established standards, the value of the heat transfer resistance index of external walls must be at least 3.2λ W/m •°C.

Calculation of the thickness of walls made of reinforced concrete and other structural materials is presented in Table 2. Such building materials have high load-bearing characteristics, they are durable, but they are ineffective as thermal protection and require an irrational wall thickness.

table 2

Structural and thermal insulation materials are capable of being subjected to fairly high loads, while significantly increasing the thermal and acoustic properties of buildings in wall enclosing structures (Table 3.1, 3.2).

Table 3.1

Table 3.2

Thermal insulation building materials can significantly increase the thermal protection of buildings and structures. The data in Table 4 shows that the lowest values ​​of the thermal conductivity coefficient are found in polymers, mineral wool, and slabs made from natural organic and inorganic materials.

Table 4

The values ​​of the tables of thermal conductivity of building materials are used in calculations:

• thermal insulation of facades;
• general building insulation;
• insulating materials for roofing;
• technical insulation.

The task of choosing optimal materials for construction, of course, implies a more comprehensive approach. However, even such simple calculations already at the first stages of design make it possible to determine the most suitable materials and their quantities.

Thermal conductivity of polystyrene foam from 50 mm to 150 mm is considered thermal insulation

Expanded polystyrene boards, colloquially referred to as polystyrene foam, are an insulating material, usually white. It is made from thermally expanded polystyrene. In appearance, the foam is presented in the form of small moisture-resistant granules; during the melting process at high temperatures, it is smelted into one whole, a slab. The sizes of the granule parts are considered to be from 5 to 15 mm. The outstanding thermal conductivity of 150 mm thick foam is achieved due to a unique structure - granules.

Each granule has a huge number of thin-walled micro-cells, which in turn increase the area of ​​contact with air many times over. We can say with confidence that almost all polystyrene foam consists of atmospheric air, approximately 98%, in turn, this fact is their purpose - thermal insulation of buildings both outside and inside.

Everyone knows, even from physics courses, that atmospheric air is the main insulator of heat in all thermal insulation materials; it is in a normal and rarefied state, in the thickness of the material. Heat-saving, the main quality of polystyrene foam.

As mentioned earlier, polystyrene foam is almost 100% air, and this in turn determines the high ability of polystyrene foam to retain heat. This is due to the fact that air has the lowest thermal conductivity. If we look at the numbers, we will see that the thermal conductivity of polystyrene foam is expressed in the range of values ​​from 0.037 W/mK to 0.043 W/mK. This can be compared with the thermal conductivity of air - 0.027 W/mK.

While the thermal conductivity of popular materials such as wood (0.12 W/mK), red brick (0.7 W/mK), expanded clay (0.12 W/mK) and others used for construction is much higher.

Therefore, polystyrene foam is considered to be the most effective material among the few for thermal insulation of external and internal walls of a building. Residential heating and cooling costs are significantly reduced through the use of polystyrene foam in construction.

The excellent qualities of polystyrene foam boards have found their application in other types of protection, for example: polystyrene foam, which also serves to protect underground and external communications from freezing, due to which their service life increases significantly. Polystyrene foam is also used in industrial equipment (refrigerators, refrigerators) and in warehouses.

Features of the use of wall insulation

The use of insulation for external walls has some limitations. This is primarily due to such a parameter as vapor permeability. If the wall is made of a porous material, such as aerated concrete, foam concrete or expanded clay concrete, then it is better to use mineral wool, since this parameter is almost the same. The use of polystyrene foam, polyurethane foam or foam glass is possible only if there is a special ventilation gap between the wall and the insulation. This is also critical for wood. But for brick walls this parameter is not so critical.

Thermal calculation of walls made of various materials

Among the variety of materials for the construction of load-bearing walls, sometimes it is a difficult choice.

When comparing different options, one of the important criteria that you need to pay attention to is the “warmth” of the material. The ability of a material to keep heat out will affect indoor comfort and heating costs. The second becomes especially relevant in the absence of gas supplied to the house.

The second becomes especially relevant in the absence of gas supplied to the house.

The ability of a material to keep heat out will affect indoor comfort and heating costs. The second becomes especially relevant in the absence of gas supplied to the house.

The thermal protection properties of building structures are characterized by such a parameter as heat transfer resistance (Ro, m² °C/W).

According to existing standards (SP 50.13330.2012 Thermal protection of buildings.

Updated edition of SNiP 23-02-2003), during construction in the Samara region, the normalized value of heat transfer resistance for external walls is Ro.norm = 3.19 m² °C/W. However, provided that the design specific heat energy consumption for heating the building is lower than the standard value, a decrease in the value of heat transfer resistance is allowed, but not less than the permissible value Ro.tr = 0.63·Ro.norm = 2.01 m²·°C/W.

Depending on the material used, in order to achieve standard values, it is necessary to select a certain thickness of a single-layer or multi-layer wall design. Below are calculations of the heat transfer resistance of the most popular external wall design options.

Calculation of the required thickness of a single-layer wall

The table below determines the thickness of a single-layer outer wall of a house that meets the requirements of thermal protection standards.

The required wall thickness is determined at a heat transfer resistance value equal to the base one (3.19 m² °C/W).

Permissible - the minimum permissible wall thickness, with a heat transfer resistance value equal to the permissible value (2.01 m² °C/W).

Conclusion: of the most popular building materials, a homogeneous wall construction is possible only from aerated concrete and ceramic blocks. A wall more than a meter thick, made of expanded clay concrete or brick, does not seem realistic.

Calculation of wall heat transfer resistance

Below are the heat transfer resistance values ​​of the most popular options for external wall structures made of aerated concrete, expanded clay concrete, ceramic blocks, brick, with or without finishing with plaster and facing bricks, insulation. These options can be compared with each other based on the color stripe. A green stripe means that the wall meets regulatory requirements for thermal insulation, a yellow stripe means the wall meets acceptable requirements, a red stripe means the wall does not meet the requirements

Aerated concrete block wall

Wall made of expanded clay concrete block

Ceramic block wall

Sand-lime brick wall

Standardized heat transfer resistance according to SNiP - table

To build a warm house, you need insulation.
Nobody objects to this anymore. In modern conditions, it is impossible to build a house that meets the requirements of SNiP without the use of insulation. That is, it is, of course, possible to build a wooden or brick house. And they build everything the same way. However, in order to comply with the requirements of the Building Code, its wall heat transfer resistance coefficient R must be at least 3.2. And this is 150 cm of an ordinary brick wall.

Why, one might ask, build a one and a half meter “fortress wall” when it is possible to use only 15 cm of highly efficient insulation – basalt wool or polystyrene foam – to obtain the same R=3.2 indicator?

What if you live not in the Moscow region, but in the Novosibirsk region or Khanty-Mansi Autonomous Okrug? Then the heat transfer resistance coefficient for the walls will be different for you. Which one? See table.

Table 4. Standardized resistance to heat transfer SNiP 23-02-2003 (document text):

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So, in this table we are interested in two types of premises - residential and domestic. Residential premises, of course, are in a residential building, which must comply with the requirements of SNiP. And the household premises are an insulated and heated bathhouse, a boiler room and a garage. Sheds, storerooms and other outbuildings are not subject to insulation, which means there are no indicators for the thermal resistance of walls and ceilings for them.

Factors affecting thermal conductivity

The thermal conductivity coefficient of a material depends on several factors:

As this indicator increases, the interaction between material particles becomes stronger. Accordingly, they will transmit temperature faster. This means that as the density of the material increases, heat transfer improves.

Porosity of a substance. Porous materials are heterogeneous in their structure. There is a large amount of air inside them. This means that it will be difficult for molecules and other particles to move thermal energy. Accordingly, the thermal conductivity coefficient increases.

Humidity also affects thermal conductivity. Wet surfaces of the material transmit more heat. Some tables even indicate the calculated thermal conductivity coefficient of the material in three states: dry, medium (normal) and wet.

When choosing a material for insulating rooms, it is also important to take into account the conditions in which it will be used.

Material temperature

On the other hand, heat transfer in nonmetals is mainly associated with lattice vibrations and the exchange of lattice phonons. With the exception of high-quality crystals and low temperatures, the path of phonons in the lattice does not decrease significantly at high temperatures, and therefore the thermal conductivity remains constant over the entire temperature range, that is, it is insignificant. At temperatures below the Debye temperature, the ability of nonmetals to conduct heat, along with their heat capacity, decreases significantly.

Phase transitions and structure

When a material undergoes a first-order phase transition, for example from a solid to a liquid or from a liquid to a gas, its thermal conductivity may change. A striking example of such a change is the difference between this physical quantity for ice (2.18 W/(m*K) and water (0.90 W/(m*K).

Changes in the crystal structure of materials also affect thermal conductivity, which is explained by the anisotropic properties of various allotropic modifications of a substance of the same composition. Anisotropy affects different scattering intensities of lattice phonons, the main heat carriers in nonmetals, and in different directions in the crystal. A striking example here is sapphire, whose conductivity varies from 32 to 35 W/(m*K) depending on the direction.

Electrical conductivity

Thermal conductivity in metals changes along with electrical conductivity according to the Wiedemann-Franz law. This is due to the fact that valence electrons, moving freely throughout the crystal lattice of the metal, transfer not only electrical, but also thermal energy. For other materials, the correlation between these types of conductivity is not pronounced, due to the insignificant contribution of the electronic component to thermal conductivity (in nonmetals, lattice phonons play the main role in the mechanism of heat transfer).

Convection process

Air and other gases are, as a rule, good heat insulators in the absence of convection. This principle is the basis for the operation of many heat-insulating materials containing a large number of small voids and pores. This structure does not allow convection to spread over long distances. Examples of such man-made materials are polystyrene and silicide airgel. In nature, heat insulators such as animal skin and bird plumage work on the same principle.

Light gases such as hydrogen and gel have high thermal conductivities, while heavy gases such as argon, xenon and radon are poor conductors of heat. For example, argon, an inert gas that is heavier than air, is often used as an insulating gas filler in double-glazed windows and light bulbs. An exception is sulfur hexafluoride (SF6 gas), which is a heavy gas and has a relatively high thermal conductivity due to its high heat capacity.

The concept of thermal conductivity

Thermal conductivity is the transfer of thermal energy between directly contacting bodies or media. In simple terms, thermal conductivity is the ability of a material to conduct temperature. That is, when entering some environment with a different temperature, the material begins to take on the temperature of this environment.

This process is also of great importance in construction. Thus, the optimal temperature (20-25°C) is maintained in the house using heating equipment. If the temperature outside is lower, then when the heating is turned off, all the heat from the house will go outside after a while, and the temperature will drop. In summer the opposite situation occurs. To make the temperature in the house lower than outside, you have to use an air conditioner.

What affects the ability of polystyrene foam to conduct heat?

To clearly understand what thermal conductivity is, let’s take a piece of material one meter thick and an area of ​​one square meter. Moreover, we heat one side of it and leave the other cold. The difference between these temperatures should be tenfold. By measuring the amount of heat that transfers to the cold side in one second, we obtain the thermal conductivity coefficient.

Why is polystyrene foam capable of retaining both heat and cold well? It turns out that it's all about its structure. Structurally, this material consists of many sealed polyhedral cells ranging in size from 2 to 8 millimeters. They have air inside – it makes up 98 percent and serves as an excellent heat insulator. Polystyrene accounts for 2% of the volume. And by weight, polystyrene is 100%, because air, relatively speaking, has no mass.

It should be noted that the thermal conductivity of extruded polystyrene foam remains unchanged over time. This distinguishes this material from other foam plastics, the cells of which are filled not with air, but with another gas. After all, this gas has the ability to gradually evaporate, and the air remains inside the sealed polystyrene foam cells.

When buying polystyrene foam, we usually ask the seller what the density of this material is. After all, we are accustomed to the fact that density and the ability to conduct heat are inextricably linked with each other. There are even tables of this dependence, with which you can choose the appropriate brand of insulation.

However, nowadays they have come up with an improved insulation, which contains graphite additives. Thanks to them, the thermal conductivity of polystyrene foam of various densities remains unchanged. Its value is from 0.03 to 0.033 watts per meter per Kelvin. So now, when purchasing modern, improved XPS, there is no need to check its density.

Marking of polystyrene foam whose thermal conductivity does not depend on density:

Extruded polystyrene foam

Extrusion is not susceptible to moisture and rotting; it is a very durable and easy-to-install insulation.

Technoplex slabs have high strength and compression resistance and do not decompose. Due to its technical characteristics, technoplex is used to insulate blind areas and foundations of buildings. Extruded polystyrene foam is durable and easy to use.

Table of thermal conductivity of materials on M-O

Date: September 25, 2022

How to do calculations using an online calculator

To get the required values, you should enter into the online calculator the region in which the building will be operated, the selected material and the expected thickness of the walls.
The service contains information for each individual climate zone:

• t air;
• average temperature during the heating season;
• duration of the heating season;
• air humidity.

Indoor temperature and humidity are the same for each region
Information is the same for all regions:

• indoor air temperature and humidity;
• heat transfer coefficients of internal and external surfaces;
• temperature difference.

In order for the house to be warm and to maintain a healthy microclimate, when performing construction work it is necessary to carry out a calculation of the thermal conductivity of the wall materials. This is easy to do yourself or using an online calculator on the Internet. For more information on how to use the calculator, watch this video:

To guarantee an accurate determination of the wall thickness, you can contact a construction company. Its specialists will perform all the necessary calculations in accordance with the requirements of regulatory documents.

Expanded polystyrene insulation in country and cottage-type houses

Many developers use the material for external insulation of facades and ceiling structures of country houses, which are being converted for year-round living. The main range of applications for polystyrene foam insulation is finishing foundations, blind areas, and insulating cement screeds under floor tiles.

Unlike mineral wool, expanded polystyrene does not require film or mastic waterproofing, so it can be mounted directly on a flat ground surface.

• The optimal thickness of polystyrene foam insulation laid between the floor joists does not require changing its height. Sealing installation gaps and joints with a moisture-resistant putty composition allows you to exploit the properties of the insulation with the highest possible efficiency.
• Foundation thermal insulation significantly reduces temperature changes, and the absence of dampness in the basement has a positive effect on the comfort of the microclimate in the house and reduces heating costs in the winter.
• Expanded polystyrene detachable casings block heat leakage from heating and hot water supply pipes, and prevent freezing of water and sewer lines located at shallow depths.

The more than moderate cost of polystyrene foam materials is complemented by the possibility of do-it-yourself installation, which allows you to reduce the cost of thermal insulation work by 35-40%.

Buy high-quality Penoplex insulation from our company right now at a competitive price!

Tips and tricks for choosing materials

1. Don’t be lazy to spend time studying technical literature on the thermal conductivity properties of materials. This step will minimize financial and thermal losses.
2. Don't ignore the climate in your region.
   Information about GOSTs on this matter can be easily found on the Internet. Climate Feature
3. Before you begin laying insulation, make sure that the surface of the wall or ceiling is free of moisture.
   Otherwise, mold will form between the surfaces over time. Mold on the walls
4. If you plan to install non-moisture resistant material on an external wall, take care to carefully treat it with waterproofing adhesive.
   Tightening foam plastic with waterproofing
5. Do not insulate internal surfaces with synthetic materials. This will negatively affect your health.

Necessity of calculations

Why is it necessary to carry out these calculations, is there any benefit from them in practice? Let's take a closer look.

Assessing the effectiveness of thermal insulation

Different climatic regions of Russia have different temperature conditions, so each of them has its own standard indicators of heat transfer resistance. These calculations are carried out for all elements of the structure in contact with the external environment. If the structural resistance is within normal limits, then you don’t have to worry about insulation.

If thermal insulation of the structure is not provided, then you need to make the right choice of insulating material with suitable thermal characteristics.

Heat loss

Heat loss at home

An equally important task is predicting heat losses, without which it is impossible to correctly plan a heating system and create ideal thermal insulation. Such calculations may be necessary when choosing the optimal boiler model, the number of radiators required and their correct placement.

Such calculations in a building are carried out for all building envelopes interacting with cold air flows, and then summed up to determine the total heat loss. Based on the obtained value, a heating system is designed that should fully compensate for these losses. If the heat losses are too large, they entail additional financial costs, and not everyone can afford this. In this situation, you need to think about improving the thermal insulation system.

Separately, we need to talk about windows, for which the heat transfer resistance is determined by regulatory documents. There is no need to do the calculations yourself. There are ready-made tables in which resistance values ​​are entered for all types of window and balcony door structures. The heat loss of windows is calculated based on the area, as well as the temperature difference on different sides of the structure.

The calculations above are suitable for beginners who are taking their first steps in designing energy-efficient homes. If a professional gets down to business, then his calculations are more complex, since many correction factors are additionally taken into account - for insolation, light absorption, reflection of sunlight, heterogeneity of structures and others.

Thermal conductivity parameters

Based on the location and climatic features, thermal conductivity parameters vary. For example, Crimea – 2, Sochi – 2.1, Rostov-on-Don – 2.75, Moscow – 3.14, St. Petersburg – 3.18 m2 o C/W.

A certain material has its own conductivity rate. The lower it is, the less heat passes through.

Heat transfer indicators for different types of raw materials:

The thermal conductivity of building materials is interconnected with their density and degree of humidity. The same raw material, but produced by a different manufacturer, may have different coefficients. It is recommended that you remember to read its instructions. If the wall will be built from more than one raw material, the indicator must be derived for all types. Then their values ​​are summed up. After choosing building materials, the thermal resistance should be calculated. If the values ​​are the same as in the table or more, this is the correct indicator. Otherwise, the thickness of the wall or insulation increases. All data is recalculated.

Source: nastilaem.com