Using polystyrene foam you can insulate a house, an extension, a bathhouse, a garage and various outbuildings. It has a number of advantages and disadvantages that should be considered when choosing of this material and working with him.
In this article we will look at the main pros and cons of foam insulation, as well as the main features of this material.
The benefits of insulation using expanded polystyrene are difficult to overestimate. However, one of the most significant of them is its thickness. This means that the product has practically the lowest thermal conductivity coefficient.
The only material that foam plastic is inferior to is penoizol, which is a multicomponent liquid material. However, it can only be used for insulating non-residential structures. 
The reason for this is the high toxicity of the material. In addition, only professional builders, and with the help of polystyrene foam, each person can complete the finishing independently.
Light weight and low price
Another significant advantage of expanded polystyrene is its low weight. It can have a density of 15, 25 and 35 kg per m3. All types can be used for insulation. However, when purchasing insulation, you should check the weight of the package in order to obtain the appropriate density and quality. 
To properly insulate a house or other building, you should use polystyrene foam of maximum density. This is due not only to the thermal insulation properties, but also to the ease of operation. The fact is that the low density means that during operation it will easily crumble and break.
Polystyrene foam is one of the most available materials for insulation of residential and industrial buildings. In construction, expanded polystyrene sheets are most often used, but in some cases crumbs or balls can be used. 
The price for both types is practically the same. This is due to the increased popularity of balls and crumbs. They are used for wall decoration. To do this, cement is mixed with sand and balls and poured. The result is very cheap, simple and warm.
If we consider the pros and cons of foam insulation, then the versatility of its use must be mentioned as advantages.
Polystyrene foam is used for insulation:
- Sten;
- Roofs;
- Paul;
- Base;
- Residential and industrial buildings.
The use of this material is in the classic way insulation. Therefore, this material will help make the house warm and comfortable. In addition, if the main stages of work are carried out correctly, the result is quite durable and reliable, and the materials and work are inexpensive. 
At correct operation expanded polystyrene under plaster will last quite a long time without changing its qualities. Sheets are used to insulate walls, crumbs or balls are used for the roof, and extruded polystyrene foam is used for the floor or base.
Video instructions:
Other benefits:
- Polystyrene foam is one of the easiest materials to work with;
- It is very pliable, so it can be cut with a hacksaw or knife;
- In addition, you can easily make a hole in it of any size and depth. This property is useful when it is necessary to insulate surfaces with protruding cornices, windows or decorative elements;
- Lightweight foam can be glued to any surface, and after the glue has dried, it can be further processed.
But do not forget that there are also disadvantages of such insulation, which should be taken into account when making a decision.
Flammability and release of hazardous substances
The main disadvantage of expanded polystyrene is its flammability. Therefore, it cannot be used to insulate rooms in which there is a high probability of a fire.
That is why it is not recommended to insulate a ventilated façade with polystyrene foam. The voids between the material and the surface of the facade create optimal conditions for combustion. In addition, the voids additionally act as air draft. 
Over time, polystyrene foam begins to release bad smell. This is due to the natural aging process of the material. The toxic substance that causes the unpleasant odor is styrene monomer. This is why polystyrene foam can only be used for external insulation.
Detailed information in the video:
In addition, when insulating a bathhouse, it is also necessary to ensure that toxic fumes do not enter the room. When polystyrene foam is heated above 90 degrees, the amount of hazardous compounds released from the material increases tenfold.
Hygroscopicity and poor ventilation properties
Expanded polystyrene absorbs moisture. Therefore, when insulating damp surfaces you need to be careful. IN in this case It is recommended to use extruded polystyrene foam, which does not absorb moisture.
Another significant drawback is its moisture-repellent properties. Thus, if the house is built from polystyrene foam blocks, it will be impossible to maintain an optimal microclimate in the room.
When breathing indoors, water vapor enters. And if this steam does not escape naturally, the room will become very humid. IN ideal conditions moisture leaves the room through the walls and ceiling.
If you insulate the walls with foam plastic, then natural ventilation will be broken. Therefore, in this case it is necessary to consider high-quality forced ventilation.
Styrofoam harbors mice
And one more fact that needs to be pointed out when assessing the pros and cons of foam insulation is that mice breed in the material. 
Expanded polystyrene is an ideal habitat for them, because it is warm and soft. Therefore, when insulating with polystyrene foam, block the access of mice. To do this, you can finish the places where rodents can enter using mineral wool that mice don't like.
Therefore, although expanded polystyrene has a number of positive qualities, we should not forget about its shortcomings. Therefore, it should be used thoughtfully and in accordance with all technological features material.
Expanded polystyrene or polystyrene foam is a product made from polystyrene and other components.
The main advantage of this material is that it is very cheap. From thermal insulation materials today it is the cheapest.
Other advantages of polystyrene foam:
- Can be used both for insulation inside and outside buildings.
- Excellent insulation of foundations.
- It is not afraid of moisture and has a low specific gravity.
- An excellent thermal insulator, for example 1 cm of foam replaces 23 cm of brickwork.
- Interacts well with other materials.
- Most cheap material from insulation.
Polystyrene foam is also the thinnest insulation material, and its only competitor is penoizol, which is sprayed on the surface. However, only professional builders can work with penoizol, while foam plastic can be installed by anyone independently as a finish.
In addition, the material is very light, which will not affect the weight of the building as a whole and will help save on the foundation. Also in construction, sheet foam plastic is more often used, but sometimes balls and crumbs are used.
Where can I use it?
A universal material that can be used to insulate any surface:
- Roofs and walls.
- Floor and plinth.
- Industrial buildings and residential buildings.
This one of the most simple ways insulation, so many people use foam plastic. The house will become comfortable and warm, and the insulation itself is very reliable. The installation work itself and the material are inexpensive, so if you wish, you can hire a team of workers for these purposes.
To insulate walls, foam sheets are more often used, and crumbs or balls are used for the roof. The floor and base are often insulated with extruded polystyrene foam.
Other foam amenities
- Most lightweight material for independent work with it.
- It can be cut with a hacksaw or knife.
- Amenable curly cut and you can make a hole in it if there is such a need. Most often this is required if windows with cornices or decorative types are insulated
- Foam glues to any surface and is perfectly exposed additional processing, such as painting or plastering.
Negative qualities
One of the negative qualities so far lies in environmental friendliness of the product. The thing is that heated foam releases styrene, which not only affects the functioning of internal organs, but also changes the composition of the blood. And when burned, polystyrene becomes dangerous. When burned, it produces phosgene gas, which is considered a weapon of mass destruction. That is why, where the risk of fire is high, experts do not recommend using polystyrene foam as insulation.
This is especially important to know when insulating ventilated facades, since voids will intensify combustion, which means that due to air draft the fire will spread more strongly. Moreover, polystyrene foam can emit an unpleasant odor after some time. The material ages, so the effect of aging material may appear in the house. It is best to use polystyrene foam for external insulation of a building or foundation.
When insulating a bathhouse, you should also not forget about the ability of polystyrene to change the smell from heating, so it is better to use it outside as insulation or prefer mineral wool.
Mice also breed in polystyrene foam, so wooden building may get hurt. It is also not recommended to use it on walls that need to breathe, and structures that have not been exposed to chamber drying. The vapor permeability of the material leaves much to be desired.
What you need to know when insulating a house outside and inside
To insulate the inside of a house, you need to know several features, for example:
- Sheets should be no more than 30 mm in thickness.
- It is better to make the sheet perforated so that it sticks to the surface. To do this, you can roll it with a needle roller;
- The glue must be applied to the entire sheet without voids.
- To level the walls, use moisture-proof mixtures.
- For safety, it is better to prefer material with a fire-resistant coating.
Insulating external facades also has its own peculiarities, so carefully study the rules before starting work.
For exterior finishing There are also nuances, they consist of successive stages:
- For correct installation set up a profile.
- Apply glue to the foam.
- Glue to the surface with dowels.
- Reinforcing corner parts are being installed.
- Reinforce and apply a decorative protective layer.
Installation of this insulation is quick and does not require the use of additional equipment. Unlike mineral wool, it does not settle in the lungs or on the skin. In addition, it has a low cost. Be sure to entrust the work to professionals if you do not have the skills to lay insulation.
Failure to comply with the standards can lead to dampness and mold. To keep mice away, you can use small metal mesh. Possibilities on how to improve polystyrene foam and make it high-quality insulation- weight. The main thing is that even the installation work of this material will cost less, as will the material itself, in contrast to the installation of other heat-insulating materials.
All the pros and cons of the material as insulation were considered, and it is up to the buyer to decide whether to purchase it or another product.
In this material: the pros and cons of expanded polystyrene. Simple, detailed and clear. Perhaps this article will change your plans regarding home insulation. Read and comment. At the end of the article - reader survey.
Interested in foam plastic? Have you decided to use it to decorate your home? Then now we will tell you what advantages and disadvantages polystyrene foam has.
Advantages of polystyrene foam (expanded polystyrene)
1. Low price
Perhaps this is the most important advantage of this material as insulation. Now there are many other insulation materials on the market that are superior to foam plastic in a number of properties. However, in many cases, it is the cost of insulation that occupies a primary place. As a result, in many cases the choice falls on foam plastic. The amount of money that can be saved by using this material is very attractive.
2. Good thermal insulation
This is also an important advantage of expanded polystyrene. In terms of its thermal insulation performance, it surpasses most other insulation materials. Due to this, when using polystyrene foam, you can get by with the smallest thickness of insulation. Whereas when using other materials, their thickness (to achieve the same thermal insulation value) can be many times greater.
The following feature is closely related to this.
3. Light weight
This is a very light material (thanks to its manufacturing technology). And due to this (as well as high thermal insulation properties), for example, when insulating a house, a minimal load is created on the foundation and walls.
This is also an important advantage of polystyrene foam. Special meaning it acquires during insulation multi-storey buildings. There are many floors, but only one foundation!
4. Multifunctionality and wide scope of application
This material is used to insulate a wide variety of objects. So, if we talk about houses, then it is used to insulate walls, basements, floors, and ceilings.
At the same time, there are several options for insulating certain objects.
This feature makes polystyrene foam practically universal insulation. The exception is insulating the house from the inside - it is better not to use polystyrene foam for this.
5. Durability
The service life is really quite long. This has already been tested in practice. Of course, provided that this material is protected from exposure to sunlight, rodents and other negative factors.
If the appropriate insulation technology is followed, this material can last 30 years or more. Especially if high-quality foam is used, from honest manufacturers.
It is no secret that there is now low-grade material on the market that is produced without complying with all necessary standards. In this case, of course, there is no need to talk about high durability.
However, if we take into account high-quality polystyrene foam, its service life is quite long. In this indicator, it is superior to some other insulation materials.
6. High resistance against fungi and various microorganisms
Another good thing about polystyrene foam is that it is of artificial origin. This means that it does not attract any microorganisms. That is, they do not start in it and do not reproduce, as in the same wood. And, for example, mold that will be located in close proximity will not destroy the foam.
Another plus for this insulation.
7. Easy to install
Any builder who has ever worked with expanded polystyrene will say that it is easy to work with. This material is easy to cut and adapt to necessary forms, sizes. For example, insulating the outside walls of a house using polystyrene foam is done simply and quickly. The same cannot be said about some other types of insulation.
However, this is where the advantages of polystyrene foam end. And now we begin to consider the disadvantages - the disadvantages of polystyrene foam. Unfortunately, there are not so few of them.
Let us emphasize right away: we are not manufacturers of expanded polystyrene. Therefore, we will tell you the whole truth, without hiding anything.
Disadvantages of polystyrene foam
1. When burned, it releases toxic substances
We will not delve into chemical processes now. Let's just say that these substances are very toxic and dangerous.
By the way, some manufacturers hide this fact in every possible way. On the Internet you can even find fairy tales that say:
“When burning, polystyrene foam emits no more harmful substances than ordinary wood...”
Know: it is not true!
Since ancient times, people have fried meat, vegetables, and cooked other foods on fires. At the same time, they sat near the fire and warmed themselves.
And in the case of polystyrene foam... this happens even in nightmare I won't dream about it! When burned, substances that are very dangerous to life are released. How can this material be equated to wood in terms of harmfulness?
There are many cases where people were poisoned by the gases that were released when polystyrene foam burned. There are also tragic cases (Google and Yandex can help you).
Therefore, it is urgent We do NOT advise you to use this material indoors.. Be aware of the high fire hazard. Electrical wiring, fire household appliances... Anything can happen. After all, even small fire the foam is enough to release hazardous substances. Why do you need this?
If you decide, for example, to insulate a house using this material, then do it only from the outside. Do not insulate the inside under any circumstances!
And even if you insulate the house from the outside, be sure to protect the foam from accidental fire. Take care not only of your health, but also of the health of those around you.
Does all foam burn the same?
No. There is ordinary polystyrene foam, which, when in contact with fire, ignites easily and continues to burn, even on its own.
And there is self-extinguishing polystyrene foam, which does not support combustion (a favorite phrase of many foam manufacturers). They say, “it does not support combustion, it extinguishes itself, which means this material is not dangerous.”
Yes, self-extinguishing foam will not burn on its own. However, if there are other materials nearby that will support combustion well (for example, wood), then self-extinguishing will not do anything. Such expanded polystyrene, under the influence of external fire, will continue to burn and still release harmful, toxic substances.
Moreover, there is important point! Not every self-extinguishing foam can actually be self-extinguishing. The fact is that now on the market there are many low-grade materials manufactured with large deviations from technological standards.
In other words, the packaging may say that the material is self-extinguishing, but in reality it is not. This type of foam can burn beautifully on its own. Consumer deception!
Therefore, when purchasing, always ask for a quality certificate; give preference only to reliable, trusted manufacturers.
2. Release of harmful substances even at low temperatures
It must be taken into account that over time, expanded polystyrene (especially low-grade) is capable of releasing a considerable amount of a harmful substance into the atmosphere - styrene. This is especially true in rooms where the air is subjected to intense heating (for example, a kitchen, a bathhouse).
Therefore, remember: no insulation indoors! And no decorative ones polystyrene foam boards We do not advise you to glue it to the ceiling. Think about your health and the health of your children!
3. Creates a vapor barrier
As you know, water vapor accumulates in rooms over time, which tends to escape outside (to the street). As they accumulate, the vapors move up and to the sides, trying to pass through the walls and ceiling of the building. And, as they say, if “the walls and ceiling breathe,” then everything will be fine - water vapor will gradually come out without creating dampness in the house.
But if on the way there is material that does not allow steam to pass through (or passes through, but poorly), then the situation will be different. This will lead to the fact that water vapor will not be able to escape normally from the room to the outside. Because of this, it will be damp, the windows will become covered with condensation, mold may appear, an unpleasant odor, etc. In short, the microclimate in the room will worsen.
So... foam plastic is precisely the material that creates a vapor barrier - it prevents water vapor from escaping outside. This will be especially noticeable if, for example, not only the walls, but also the ceiling are insulated with this material.
Yes, some say that supposedly foam plastic (for example, PSB-S) has normal vapor permeability, sufficient for steam removal. However, in practice, as a rule, it turns out differently.
So, if we compare the characteristics of a wall made of red brick with the indicators of such foam plastic, then the vapor permeability of the second will be noticeably lower - 0.11 versus 0.05 Mg/(m*h*Pa).
Not to mention extruded polystyrene foam, which creates almost zero vapor permeability. In fact, only reinforced concrete can be insulated with such material, which also practically does not allow steam to pass through - 0.03 Mg/(m*h*Pa).
Ideally, if the wall consists of several materials, then the vapor permeability in the direction from inside to outside should increase or at least remain the same. And if in some place there is a sharp decrease in vapor permeability, this inevitably leads to the accumulation of moisture in the thickness of the wall. Over time, this moisture will negatively affect the indoor microclimate. Likewise with the ceiling.
Is it possible to somehow combat this disadvantage of polystyrene foam?
Yes, you can. To do this, you need to provide in the house quality system ventilation. And this is additional costs, and considerable ones.
4. Hygroscopicity
This is the property of a material to absorb moisture. Of course, in terms of hygroscopicity, polystyrene foam is better than many other insulation materials. For example, it absorbs much less moisture than mineral wool. However, while in water, the foam (ordinary) will absorb some of the moisture.
Therefore, for insulation and insulation of damp rooms, as a rule, it is better to use extruded polystyrene foam.
5. Afraid of sunlight
Under the influence of ultraviolet radiation, this material is destroyed. And quite quickly.
This must be taken into account both during storage and during direct use. For example, after covering the walls of a house, you need to cover the insulation as quickly as possible protective layer glue, plaster. Styrofoam should not be allowed to fall on the foam for months. Sun rays. Otherwise, its surface will be severely damaged (it will begin to turn yellow and crumble).
6. Whole until the mice get there
Mice chew polystyrene foam, and quite actively (we wrote about this earlier). If rodents get to it, it's a disaster. There will be a hole on a hole. Mice make burrows in this material and build nests for breeding. Apparently rodents like it to be warm and easy to chew on.
7. Not resistant to solvents
This also needs to be taken into account. When any solvents get on the surface of polystyrene foam, it begins to collapse almost instantly. As if it dissolves, melts from their action.
Therefore, if it is necessary to paint this material, the choice of paint must be taken seriously. Only these can be used paints and varnishes, which do not contain solvents. No white spirits or solvents!
8. Low resistance to mechanical damage
You can't say what it is big drawback polystyrene foam Nevertheless, it is there. Whatever you say, this material has low strength and is easily destroyed by mechanical stress. This manifests itself not only during installation, but also, for example, during transportation. You can often see sheets with uneven edges (there are chips).
Of course, this parameter directly depends on the density of the foam. The higher it is, the greater the strength. However, whatever one may say, the material needs additional protection.
Pros and cons of polystyrene foam: drawing conclusions
As you can see, there were more disadvantages than advantages. However, we promised you that we would tell the whole truth, without hiding anything. We kept our promise.
Whether or not to use this material for your purposes is, of course, up to you to decide. In any case, now you know about all the pros and cons of polystyrene foam. This means you will make the right choice.
The general conclusion can be drawn as follows.
Yes, polystyrene foam has high thermal insulation characteristics, attractive price and other advantages. However, one must also take into account the risks and health threats that this material can carry. And the feasibility of using polystyrene foam should be considered in each case separately.
And now the poll. Tell us what you think about this material.
Survey
Should I use polystyrene foam as insulation for my home?
High-quality thermal insulation is a guarantee of reduction financial costs and maintaining the temperature in the premises at the proper level. That is why today wall insulation with polystyrene foam is becoming increasingly popular. This also makes it possible to significantly (sometimes up to two times!) reduce home heating costs.
If you want to reduce heat loss from your home, then you should think about external insulation. Internal ones are less efficient, so many homeowners don’t even consider it necessary to spend money on it.
In addition, the use of foam plastic on outside walls allows you not to disturb the carefully designed interior and not reduce the area of the premises even by a few centimeters. The material perfectly resists moisture, so the walls (both wooden and brick) will last you longer. But in order for the work to be done really efficiently, you need to know exactly what and how to insulate the house from the outside.
Pros and cons
Like any other material, foam plastic has certain pros and cons, which you should definitely find out about before starting work. Let's start with the pros:
- Excellent thermal insulation. The sheet of relatively small thickness allows you to reduce heat loss several times.
- Ease of installation. It becomes possible to insulate walls with polystyrene foam from the outside with your own hands. You don’t have to invite people who have special equipment and skills - all the work can be done yourself.
- Light weight ensures simplicity and ease of transportation and installation, for which it is highly valued by experienced specialists.
- The material can easily withstand prolonged exposure to ultraviolet radiation, high humidity and frequent temperature changes, thanks to which users leave only positive reviews.
Unfortunately, polystyrene foam also has weaknesses:
- Fragility. A slight blow can break even a thick sheet, which will affect the quality of the house’s thermal insulation.
- Fire hazard. It burns well and, even worse, emits a large number of caustic substances.
Calculation and technology of thermal insulation with foam plastic
First, clean thoroughly work surface from dirt, dust, crumbling plaster. It should be even, relatively smooth and, of course, clean. Use a regular brush with synthetic bristles. If there are deep cracks and cracks, it is better to immediately eliminate them with plaster. When it dries, you can start working.
The technology of facade insulation with polystyrene foam is simple. A special construction adhesive is applied to the surface. If you want to improve its adhesion to the surface, the wall can be primed in advance. The fitted sheets are placed on the glue. Press them firmly enough for a few seconds and then release.
After 12-24 hours have passed (depending on the brand of glue), you can continue working. A thick layer of glue (up to 5 mm) is applied to the foam plastic, into which the mesh is immersed.
When the glue dries, the wall needs to be plastered and painted.
There are other technologies, for example, for insulation wooden house sheets of foam plastic are installed on the sheathing - this ensures air circulation and prevents the development of fungus, mold and rotting of the wood.
Cost estimate, prices of materials and work
Before you start insulating the walls of your house with Penoplex or polystyrene foam, you should choose optimal thickness insulation. Moreover, the market allows you to purchase domestic and foreign material from dozens of different manufacturing companies. Of course, the greater the thickness, the higher its thermal insulation qualities. However, along with them, the cost also increases.
For example, one sheet from the popular company Knauf with an area of 1.2 square meters and a thickness of 20, 30, 40, 50 and 100 mm. costs 40, 50, 70, 90 and 190 rubles respectively. If you prefer to a domestic manufacturer, then insulating the walls of the house from the outside will cost a little less. For example, when using products from the Penoplast-Opt company, you can significantly reduce costs. Here a square meter is 50 mm thick. will cost 90 rubles, and with a thickness of 150 mm - 270 rubles.
If you do not want or cannot do the work yourself and decide to invite specialists, then the cost of their services may vary depending on the region. For example, in the Moscow region for high-quality insulation of one square meter for the facade with polystyrene foam you will have to pay at least 1,000 - 1,200 rubles.
Advantages and disadvantages. An increasing number of homeowners, frightened by heating bills, decide to insulate their homes and choose polystyrene foam as a thermal insulator.
– pros and cons, how not to make a mistake in choosing, the article is devoted to these issues.
Let us stipulate right away: polystyrene foam and polystyrene foam are produced from the same raw materials, but this different materials. Polystyrene foam is a fragile, flammable material that decomposes in light and cannot withstand mechanical loads and is intended for packaging. For insulation, polystyrene foam is used - a denser material with completely different characteristics, but in common parlance both materials are called the same, which often leads to confusion.
The production process of foamed organic substance styrene is a technical development of the American concern BASF in 1951. The insulation, called “styrofoam,” consisted of 98% air filling a cellular foam base. The material was characterized by low thermal conductivity, low water absorption and vapor permeability.
As a result of improvements in technology, extruded polystyrene foam appeared - self-extinguishing foam. Their main difference is in the structure of the cells: expanded polystyrene has an open structure, while extruded material has a closed structure, which reduces water absorption and increases fire resistance.
Quality and specifications foam plastics in Russia is declared by GOST 15588-2014 “Heat-insulating polystyrene foam boards. Specifications" To insulate walls in a system with an external plaster layer, in accordance with this document, it is necessary to use polystyrene foam marked F - facade.
The letter G in the marking of the plates indicates the content of graphite, which gives lower thermal conductivity and colors the material in the mass in a silver-black color.
We are for it"!
This is what people say who have recently insulated their home with polystyrene foam. Indeed, the material has a lot of positive qualities:
- Low weight.
- Low thermal conductivity.
- Excellent noise absorption performance.
- Self-extinguishing property.
- Ease of use.
- Low cost.
Yes, indeed, polystyrene foam is second only to polyurethane foam in thermal conductivity, volume weight slabs from 10 to 50 kg per 1 m3, while the best materials made of mineral wool it starts at 30-35 kg/m3, it dampens noise perfectly and fades out in 1 second, and any homeowner can work with it.
And we are “against”
This is what people say who have insulated a house without taking into account the specifics of the material. Let's list negative qualities material:
- Low vapor permeability.
- High water absorption.
- Low resistance to mechanical damage.
- Instability to light.
- Rodents love it.
Due to low vapor permeability, it is undesirable to use this material to insulate the outside of a house made of wood - without installing two ventilated gaps, which is difficult and time-consuming. A moisture absorption of 4% with low quality work will ensure that the material gets wet and loses its heat-insulating qualities after 2 seasons.
When insulating as part of a light plaster system, any accidental impact can lead to the destruction of the protective layer, and the exposed foam plastic simply crumbles under the influence of sunlight. And finally, the last thing: mice prefer this material for making nests in the thickness of the insulation - it’s warm, it’s easy to gnaw through passages.
In wet plaster systems, metal protects against rodent infestation. perforated corner- a starting profile, but when installing a ventilated façade they easily overcome this obstacle.
Where to use polystyrene foam?
So why, despite everything negative qualities Is polystyrene foam popular? How to use best qualities material to make your home comfortable and reduce negativity to a minimum?
Let's consider. A little bit of thermal engineering in the tape: for the insulation system to work, it is necessary that the vapor permeability of the materials increases from the inside out, and the thermal conductivity of the materials, on the contrary, decreases.
That is, the material on the street side should have greater internal material, vapor permeability and lower heat transfer resistance coefficient.
Comparing heat transfer resistance building materials and polystyrene foam, we see that this indicator satisfies the requirement, but when comparing vapor permeability, it turns out that in the case of wood, the indicator of polystyrene foam is lower than that of wood, which means that the dew point will be at wooden structure, which will lead to condensation settling on it, getting wet and rotting.
When insulating a wooden house with polystyrene foam from the inside, the requirement is also not met, since the heat transfer resistance coefficient of wood is greater than that of insulation.
conclusions
Polystyrene foam is not suitable for insulation wooden houses, but will cope perfectly with the task of retaining heat with walls made of brick or light cellular concrete. When choosing an insulation system, it is better to choose a wet (plaster) system if the house is located near crop areas where voles are a common occurrence.
Taking into account everything said above and strictly following the manufacturers’ instructions when performing work, the use of polystyrene foam for insulation is justified and will last longer than the guaranteed 50 years.