Before you buy insulating materials for a home, it is worth calculating the thickness of the insulation. No amount of recommendations or experience from your neighbors will help determine how much protection your home specifically needs. The reason is that the effectiveness of thermal insulation is influenced both by the climate in a particular region and by the characteristics of the frame or roof of the house itself. The main goal of such calculations is to determine the required layer of insulation, which will make it possible to provide reliable protection from heat loss through enclosing structures.
How to do it?
Any online calculator program will help simplify the task for inexperienced builders. These are easy to find on construction portals or on the official websites of manufacturers of thermal insulation materials. Or you can try to do all the calculations yourself. In any case, you need to know the requirements for thermal protection of buildings in your climatic region. They are in SNiP 02/23/2003 and on the Internet in the form of summary tables, which provide data on all major cities Russia.
For example, let’s take the data for Moscow and the region – 3.14 m2 °C/W. This is the resistance that all layers of the main structure, air and insulating layers, as well as exterior decoration. We will build on the given figure, not forgetting that we are talking about the minimum acceptable indicator.
Here, the thermal engineering calculation of the required insulation thickness begins with an analysis of the selected building material and capacity of load-bearing walls:
- Concrete has the highest heat transfer coefficient - 1.5-1.6 W/m °C.
- Brick has a relatively low thermal conductivity of 0.56 W/m °C, but in masonry this figure actually doubles and is already 1.2.
- Good performance for cellular concrete and gas blocks is about 0.2-0.3 W/m °C.
- Wood (depending on the selected species) – 0.10-0.18 W/m°C.
However, these figures in themselves only give an idea of the thermal insulation characteristics different materials. For calculations, it is also necessary to take into account the thickness of the structure. Dividing it by the heat transfer coefficient, we get the resistance real walls.
Let's take a standard 30 cm thick aerated concrete masonry: R = 0.3 m ÷ 0.2 W/m °C = 1.5 m °C/W.
We arm ourselves with a calculator and find that for thermal protection of the walls of such a house built in Moscow, it is not enough: 3.14-1.5 = 1.64 m ° C / W.
Now you can choose insulation for walls by considering several materials with different thermal conductivity values, but giving the same effect due to thickness:
- Mineral wool (0.04 W/m °C) – 1.64x0.04 = 0.0656 m or 66 mm.
- Foam plastic (0.05 W/m °C) – 1.64x0.05 = 0.082 m (82 mm).
- Penoplex (0.03 W/m °C) – 1.64x0.03 = 0.0492 m (50 mm).
Next, we include the cost of materials in the calculation and do not forget about the logic. Penoplex, although it shows the most best characteristics, For aerated concrete walls It’s simply not suitable, so you’ll have to choose between mineral wool and polystyrene foam. A cubic meter of inexpensive basalt insulation, which is suitable for insulating a facade, will cost about 2,500 rubles. If we take slabs with a thickness of 70 mm, for this amount it will be possible to cover 14.3 m2.
PSB-S-25f costs 2600 rub/m3. At first glance, the difference is small, but let’s recalculate how much area the slabs will cover if the thermal insulation thickness is 100 mm. It should be explained here that 80 mm sheets do not meet the minimum thermal protection requirements, and 90 mm sheets are not commercially available. So, in fact, for 2,600 rubles you can insulate only 10 square meters. It turns out that the difference in price between polystyrene foam and mineral wool is 4%, and in the insulated area – 43%. However, it's worth doing one more calculation on the calculator. It will show how much a curtain wall will cost to protect the mineral wool itself, and how the cost will change after plastering and painting the PSB.
For slopes and flat designs Similar calculations are performed, but here you will have to take into account all the working layers in the overall pie. Thus, the insulation for the roof and its thickness are obtained by subtracting the resistances of all other elements from the norm according to SNiP (adjusted by 0.16), after which we simply multiply the difference by its own thermal conductivity coefficient:
S = (R-0.16-S 1 /ʎ 1 -S 2 /ʎ 2 -…-S i /ʎ i)·ʎ (m).
Instead of worrying, you can find recommendations for roof insulation for your region. In Moscow, 200 mm of basalt wool is considered the norm. From here, through the proportion of the thermal conductivity of the materials, we obtain an equivalent replacement: 250 mm of foam plastic or 150 mm of Penoplex.
The same calculation rules apply here, but the standard value of R0 changes. If we are talking about floors above a cold basement, in MO they must have total resistance 4.12 m2 °C/W, but adjusted for the coefficient of thermal uniformity of slabs (for reinforced concrete this is 0.8, for wooden floors 0.9). The figure 0.17 is also subtracted from the resulting figure according to SNiP requirements. Then the resistance will be equal to:
R = R 0 ÷ 0.8 – 0.17 = 4.12 ÷ 0.8 – 0.17 = 4.98 m2 °C/W.
Again we subtract the thickness of the ceiling divided by its thermal conductivity, and multiply the finished result by the conductivity of the insulation itself. For example, for Penoplex on a slab with cement screed with a total thickness of 26 cm we get a layer of 160 mm. From here it is already possible to calculate the thickness of mineral wool (215 mm) and foam plastic (265), which could replace it.
When choosing a material for thermal insulation, a reasonable question arises: “How to calculate the thickness of insulation for walls?”, especially since all sorts of sizes of sheets, mats and rolls are available for sale. The answer depends on many factors.
What does thickness depend on?
Material
Calculating the thickness of insulation for walls is impossible without taking into account many related factors and conditions. It is incorrect to talk about the parameters of some spherical insulation in a vacuum. There are many various materials, each of which has its own characteristics.
Here is a list of thermal conductivity coefficients of various thermal insulation materials:
- Glass wool URSA - 0.044 W/m×K;
- Stone (basalt) cotton wool Rockwool- 0.039 W/m×K;
- (foam) - 0.037 W/m×K;
- Ecowool - 0.036 W/m×K;
- Polyurethane foam () - 0.03 W/m×K;
- Expanded clay - 0.17 W/m×K;
- Brickwork - 0.520 W/m×K.
- Glass wool URSA - 189 mm;
- Stone (basalt) wool Rockwool - 167 mm;
- Expanded polystyrene (foam plastic) - 159 mm;
- Ecowool - 150 mm;
- Polyurethane foam - 120 mm;
- Expanded clay - 869 mm;
- Brickwork - 1460 mm.
- Operating density;
- Load on the wall structure;
- Environmental safety and composition;
- Biological resistance;
- Chemical properties and interactions;
- Corrosion resistance;
- Fire safety;
- Permeability to air and steam;
- Condensation formation;
- The presence of “cold bridges” and heat losses associated with them;
- Hygroscopicity;
- Moisture resistance.
On the picture mineral wool, it has a standard minimum thickness that meets the requirements of the middle zone climate
Next, based on these data, one more important quantity should be determined - resistance to heat transfer or simply thermal resistance. This value is equal to the ratio of the temperature difference at the edges of the material to the value heat flow, passing through its thickness.
To calculate resistance (R), the formula is adopted:
R = wall thickness/wall thermal conductivity coefficient.
It becomes obvious that the thickness of the insulation depends not only on the properties of the heat insulator material, but also on the properties of the material from which the wall is made, its thickness and finish.
Already at this stage it is clear that calculations can be carried out only for a specific insulation material, taking into account a whole bunch of accompanying conditions and factors. For example, the thickness of foam plastic for wall insulation can greatly depend on the type of installation and brand of material, manufacturer, quality of raw materials and many other parameters.
Advice! When it comes to individual construction, you should not go into the jungle of materials science and thermal engineering. It is enough to consider acceptable standards for your region with a reserve, the maximum overexpenditure will be insignificant, you are not developing a city.
The thickness of the insulation for external walls must be no less than a certain value; there is no point in calculating it for sure for many reasons:
- Firstly, you will still be forced to make some assumptions, assumptions and averaging, because you still cannot predict the weather and accurately indicate the movement of heated air masses;
- Secondly, even if you get the thickness value accurate to the micron, you still won’t be able to find a suitable size on sale, since they are standard and quite roughly discrete, in increments of several tens of millimeters;
- Thirdly, as they say, the heat doesn’t break your bones, too warm is not a problem, just open the window, but when it’s cold you have to spend money on heating or endure discomfort;
- Fourthly, a small margin of thickness will not increase the total volume of material so significantly as to seriously worry about it.
Advice! Insulation thickness for external walls must be greater than some minimum acceptable value. At the same time, you can play it safe and make a larger reserve, you can save money and set the thickness as close as possible to the permissible minimum, it’s up to you.
Climatic conditions
Following important condition, which should be taken into account when calculating the thickness of foam for wall insulation, this climatic conditions areas where it is intended to be used. This is an obvious fact, but it is still worth mentioning separately.
Once you have decided on the material, you should find out in which climate zone it will be used. Manufacturers, as a rule, provide information on the recommended insulation parameters for different temperature conditions and zones.
Wall design
To understand how meaningless universal instructions when calculating the thickness of a particular material, we should recall one more important detail: wall structures. The number of layers, their composition, order, and thickness play a role here. As you can see, there can be a lot of options.
It is also important where the heat insulator is located - outside, on the side of the room or inside the structure. No less important are waterproofing, vapor barrier, the presence of drafts and movement of heated air masses, convection, infrared radiation and wind intensity in the region.
Do not forget about the finishing, plaster thickness, façade coating and the presence of additional insulators. Combinations of thermal insulation materials are often used, such as polystyrene foam-penofol, mineral wool-penofol, foam plastic-expanded clay, foam concrete-foam and others. All this should also be taken into account.
Other factors
When calculating the parameters of insulation, factors such as the purpose and functions of insulation are also taken into account.
For example, it's one thing when you're building a frame building where the foam will be the main barrier to heat. Here you should play it safe and choose the maximum thickness of insulation, because the very possibility of living in the house will depend on it.
It’s a completely different matter when you are not satisfied with the level of comfort in a brick house or you want to reduce heating costs. In this case, it would be advisable for you to choose the minimum reasonable thickness of the material, because the price of such repairs is also important, since we are talking about savings.
The method of construction also plays an important role: if you work with your own hands, it is important for you to control and calculate everything. If you hire a professional contractor, your task is to choose the right company, because its specialists will, in any case, be involved in calculating all the parameters.
Again, the insulation of a loggia or balcony has completely different requirements. These objects have thin walls, are blown with cold air on three sides, and do not have heating radiators. As you can see, the devil is in the details; universal rules are most often nothing more than a myth.
For any home, a comfortable and warm atmosphere is important, which will make your stay pleasant and convenient. The correct microclimate will allow you to get rid of many troubles, including dampness, heat loss, and too high heating costs. To avoid such negative aspects, it is necessary to correctly select the type and thickness of insulation.
When choosing insulation, such parameters as the region of residence, the purpose of the room, as well as the material from which the house is built are important.
Today construction market offers numerous options for insulation, which differ not only in size and thickness, but also in the type of raw materials for production, operational characteristics. When choosing a heat insulator, it is necessary not only to clarify the thickness, but also to determine for which wall material it will be optimal. You should pay attention to the climatic region and wind loads. For example, the value for the thickness of the insulation will indicate for which specific room the insulator is selected. For a living room this will be one indicator, but for an attic or basement it will be completely different.
Parameters for insulation
Insulation materials are selected based not only on thickness, but also on other indicators. What thickness to take depends on the following:
- climatic region for the construction site;
- main wall material;
- purpose of the room, its level above the ground;
- manufacturing material.
Manufacturers offer various options. Many people claim that aerated concrete or expanded clay concrete is excellent option for construction warm home, here you can save on insulation. But is this really so? It is necessary to compare thermal conductivity coefficients. In order for the thickness to be selected correctly, it is necessary to take into account that all insulation materials differ in their characteristics, their thermal conductivity indicators will be different.
As comparative data you can take:
- Expanded polystyrene thermal insulators with a thermal conductivity coefficient of 0.039 W/m*°C with a thickness of 0.12 m.
- Mineral wool (basalt wool, stone) with data of 0.041 W/m*°C and 0.13 m.
- Iron concrete walls with data of 1.7 W/m*°C and 5.33 m.
- Solid sand-lime brick with data of 0.76 W/m*°C and 2.38 m.
- Hollow (holey) brick with data of 0.5 W/m*°C and 1.57 m.
- Glued laminated timber with values of 0.16 W/m*°C and 0.5 m.
- Expanded clay concrete (warm concrete) with values of 0.47 W/m*°C and 1.48 m.
- Gas silicate blocks with data of 0.15 W/m*°C and 0.47 m.
- Foam concrete blocks with a thermal conductivity coefficient of 0.3 W/m*°C at 0.94 m.
- Slag concrete with data of 0.6 W/m*°C and 1.8 m.
Based on the listed data, you can see that the thickness of the wall to ensure a normal and comfortable microclimate is from one and a half meters. But that's too much. It is best to make the wall thinner, but use a layer of mineral wool or expanded polystyrene with a thickness of only 12-13 cm. This will be much more economical.
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Comparative characteristics
Today, not only comfort and savings depend on what material you choose for insulation, but also the availability free space in the house and on the site. Too thick brick walls take up a lot of space, it can be used more efficiently.
Comparison of thermal conductivity coefficients:
- Expanded polystyrene sides PSB-S-25 with a value of 0.042 W/m*°C and a required thickness of 124 mm.
- Rockwool mineral wool for facade insulation: thermal conductivity coefficient - 0.046 W/m*°C, required thickness -135 mm.
- Glued laminated timber from spruce or pine with indicators of 500 kg/m³ according to GOST 8486: thermal conductivity coefficient - 0.18 W/m*°C, required thickness - 530 mm.
- Special warm ceramic blocks with a layer of thermal insulating adhesive: thermal conductivity coefficient -0.17 W/m*°C, required thickness - 575 mm.
- Aerated concrete blocks 600 kg/m³: thermal conductivity coefficient - 0.29 W/m*°C, required thickness - 981 mm.
- Sand-lime brick according to GOST 379: thermal conductivity coefficient - 0.87 W/m*°C, required thickness - 2560 mm.
According to the data presented, it is clear that mineral wool, expanded polystyrene, and ordinary timber are the leaders among other materials.
Using them as insulation makes it possible to build brick or concrete walls of smaller thickness. If the house is being built in a warm region, then 10 cm of insulation is sufficient. For colder regions, 12-13 cm is already required, but taking into account the material from which the main wall of the house is made.
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Example of insulation calculation
The choice of thickness for a heat insulator must begin with the fact that the material is selected for its intended purpose for a specific room and according to temperature zone. All zones that are used for calculations can be found in special reference books. Among the frequently used 4 are:
- 1 zone: from 3501 degree days;
- Zone 2: 3001-3501 degree days;
- Zone 3: 2501-3000 degree days;
- Zone 4: up to 2500 degree days.
The following calculation options can be cited as an example:
- Minimum valid values for thermal resistance are represented by 4 zones of 2.8; 2.5; 2,2 and 2.
- Floors, coverings for unheated, unused attics: 4.95; 4.5; 3.9; 3.3.
- Cold cellars, ground floors: 3,5; 3,3; 3; 2,5.
- Ceilings for unheated plinths, basements, which are located at ground level: 2.8; 2.6; 2.2; 2.
- Floors for basements located below ground level: 3.7; 3.45; 3; 2.7.
- Balcony structures, display cases and panoramic windows, walls around them, translucent special facades, verandas, covered terraces: 0,6; 0,56; 0,55; 0,5.
- Front doors for apartment buildings, hallways for large public buildings: 0,44; 0,41; 0,39; 0,32.
- Entrance premises, corridors, hallways, halls for private low-rise buildings: 0.6; 0.56; 0.54; 0.45.
- Entrance halls and halls for premises located above the ground floor level: 0.25; 0.25; 0.25; 0.25.
Using this indicator, you can calculate the thickness of the heat insulator of any structure. For example, the walls of a house are made of sand-lime brick 51 cm. The insulation is carried out using 10 cm thick foam plastic boards. To determine whether the planned thickness of the insulation is suitable, you simply need to calculate the coefficient for the thermal resistance of the foam plastic and the wall, after which the resulting values are added and compared with those presented above.
For walls 51 cm, the following data is obtained:
- The thermal conductivity coefficient of sand-lime brick is 0.87.
- The thickness of the wall 51 must be divided by 0.87 to obtain the thermal resistance of the brick equal to 0.58.
- With polystyrene foam they do things differently. Its thickness is divided by the thermal conductivity coefficient of this material 0.043, the result is 2.32.
- Now we need to add up the obtained values, the result is 2.88. This indicator must be compared with those given above. If the received data for external walls made of sand-lime brick coincide with those required for a particular region ( climatic zone), then 10 cm of polystyrene foam will be quite enough.
It must be remembered that if the insulation is used for colder areas, then its thickness should be 12-14 cm to create comfortable conditions living in a house.
To choose the right thermal insulation material, you need to carefully determine its parameters. The influence is exerted by the climatic zone in which the house is being built, what material its walls are made of, and for what part of the structure the heat insulator is used. It is important to immediately pay attention to the features of using a certain type of insulation. Usually mineral wool or polystyrene foam is purchased, but their characteristics are different, so you need to calculate separately for each material.
Online insulation calculator, designed to calculate the amount and volume of insulation for external walls and the side surface of building foundations. The calculations take into account window and door openings, as well as the cost of insulation and additional materials.
When filling out the data, pay attention to the additional information with the sign Additional Information
Expanded polystyrene (EPS) and Extruded polystyrene foam (EPS)
I am one of the most accessible and effective lungs insulation materials. More than 90% consists of air, which is the best heat insulator. Conventional PPS is used to insulate the external walls of buildings, but since it is a moisture-permeable material, it is not recommended to use it for insulating foundations. For these purposes, EPPS is best suited, which also serves as a moisture-proof layer when insulating foundations.
Stone (basalt) wool mats
Currently the most well-known manufacturers slabs stone wool are such companies as "Rokwool" and "TechnoNIKOL".
The most important advantages of this material are ease of processing; to work with it you do not need any special equipment, just a knife or saw with fine teeth. It is worth remembering that the wool slabs must be joined very tightly, but it is forbidden to tamp them or compress them. The inside of the mats is covered vapor barrier membrane, and on the outside with a windproof film, this is necessary in order to protect the cotton wool from moisture.
With strong moisture, stone and mineral wool loses its heat-saving characteristics
Sprayed insulation
This method of insulation is not yet very widespread in our country. Mainly for wall insulation frame houses polyurethane foam is used. It consists of two liquid substances that turn into foam under air pressure, and after the entire space is filled, its excess is cut off. Working with such material is reminiscent of working with polyurethane foam.
Ecowool
IN Lately The use of insulation such as cellulose fibers or ecowool has become very popular. It is made from natural material and does not require additional protection, this type of insulation is most suitable for those who want to make their home environmentally friendly.
And there are two known methods of installation: the dry method and the wet method.
- Dry method
- Wet method
Using a special machine, the wool is blown into an insulated layer until the required density is achieved. The disadvantage of this method is that over time it can shrink and begin to transmit heat into the upper layers. Although many manufacturers guarantee that there will be no shrinkage for at least 20 years.
This can be done using special equipment; ecowool is “glued” under pressure both to the walls and to each other, this avoids shrinkage. The main disadvantage is that wet laying of ecowool must be carried out outside before covering the walls.
Further presented full list calculations performed with brief description each item. If you haven't found the answer to your question, you can contact us via feedback.
General information on the calculation results
- Quantity of insulation - Total volume of required insulation
- Insulation area - Total insulation area including gables, window and door openings
- Number of dowels "fungi" - The total number of dowels "fungi" with a consumption of 6 pieces per 1 square meter insulation.
- In terms of insulation - The total weight of the insulation of the specified density. Check the density of the material with the sellers.
Until the second half of the 20th century, few people were interested in environmental problems; only the energy crisis that broke out in the West in the 70s raised the question: how to save heat in the house without heating the street and without overpaying for energy.
There is a solution: insulating the walls, but how to determine what thickness of insulation for the walls should be so that the design matches modern requirements by heat transfer resistance?
The effectiveness of insulation depends on the characteristics of the insulation and the method of insulation. There are several in various ways, which have their own advantages:
- Monolithic structure, can be made of wood or aerated concrete.
- Multilayer construction in which the insulation occupies an intermediate position between the outer and internal part walls, in this case, at the construction stage, ring masonry is performed with simultaneous insulation.
- External insulation using a wet (plaster system) or dry (ventilated facade) method.
- Internal insulation, which is performed when it is impossible to insulate the wall from the outside for some reason.
To insulate already constructed and operating buildings, external insulation is used, as the most effective method reducing heat loss.
Calculate the thickness of the insulation
Thermal insulation outer wall reduces heat loss by two or more times. For a country, most of whose territory belongs to a continental and sharply continental climate with a long period of low negative temperatures, like Russia, thermal insulation of enclosing structures provides a huge economic effect.
Whether the thickness of the heat insulator for external walls is correctly calculated determines the durability of the structure and the microclimate in the room: if the thickness of the heat insulator is insufficient, the dew point is located inside the wall material or on it inner surface which causes condensation to form, high humidity, and then the formation of mold and fungal attack.
The method for calculating the thickness of insulation is prescribed in the Code of Rules “SP 50. 13330. 2012 SNiP 23–02–2003. Thermal protection of buildings."
Factors influencing the calculation:
- Characteristics of the wall material - thickness, design, thermal conductivity, density.
- Climatic characteristics of the building area - the air temperature of the coldest five-day period.
- Characteristics of materials of additional layers (cladding or plaster of the inner surface of the wall).
A layer of insulation that meets regulatory requirements, is calculated by the formula:
In the insulation system “ventilated facade” thermal resistance the material of the curtain façade and the ventilated gap are not taken into account in the calculation.
Characteristics of various materials
Table 1
The value of the standardized heat transfer resistance of an external wall depends on the region of the Russian Federation in which the building is located.
table 2
Required layer thermal insulation material, determined based on the following conditions:
- external building envelope – solid ceramic brick plastic pressing with a thickness of 380 mm;
- interior finishing – plaster with cement-lime composition 20 mm thick;
- external finishing – a layer of polymer-cement plaster, layer thickness 0.8 cm;
- the coefficient of thermal homogeneity of the structure is 0.9;
- thermal conductivity coefficient of insulation - λA=0.040; λB=0.042.
Calculators for calculating the thickness of insulation
For the calculation you will need the following data:
- wall size;
- wall material;
- thermal conductivity coefficient of the selected insulation;
- finishing layers;
- the city in which the building being insulated is located.
The calculation will be completed in a matter of seconds.
Since we do not have our own calculator, we would like to recommend, in our opinion, a very good online calculator, which you can use to calculate the thickness of the insulator.
Results
It is advisable to provide for a reduction in the cost of heating a house at the design stage: by laying in the design walls that do not require insulation in the future, you can save significant money on operating costs.
If you need to insulate already ready house, it is not difficult to calculate the required thickness of insulation. The only disadvantage of such insulation is that its durability is less than the service life of the load-bearing wall.