When insulating a house with polystyrene foam, you need to know as much as possible about this material. Then the decision to make insulating the house with polystyrene foam, will be thoughtful and well weighed. I have already talked about the advantages and disadvantages of polystyrene foam when insulating the facade of a house, you can read it. Today I want to talk about two dangers that can await you when using polystyrene foam for insulation, both inside and outside the house.
The popularity of polystyrene foam is great, and the reason for this is its cost - cheap material, compared to other insulation materials. Therefore, it is used for insulation literally everywhere possible.
They insulate the facades of brick and stone houses. Used in insulation of frame and wooden houses. Not only the walls of the facades are insulated, but also the ceilings and walls inside the premises.
Except positive qualities, I advise you to pay attention to three significant disadvantages of polystyrene foam.
1. The fragility of the material.
2. Promotes the formation of fungal mold.
3. When a fire occurs, hazardous gas is released.
Short service life.
1. Fragility of polystyrene foam or short service life.
According to manufacturers, the shelf life of polystyrene foam is approximately 10-20 years. Naturally, subject to the right technology when insulating a house with polystyrene foam. If the technology of use is violated, the service life is significantly reduced.
Styrofoam danger #1
2. Styrofoam Hazard #1 – fungal mold on the wall of a foam-insulated house. Fungal mold spores can cause allergies and asthma. This especially applies to houses where foam insulation is done indoors. Dew point in in this case it may remain indoors, behind the foam, or move inside the wall, then the house begins to leak. The result is humidity and dampness. The effectiveness of insulation decreases significantly. Another factor is that polystyrene foam does not “breathe,” which, accordingly, can also contribute to the formation of mold. Especially if the insulation is carried out with a violation of technology and low-quality material.
The result is: nonspecific lung disease, usually this diagnosis is made by doctors.
Styrofoam Hazard #2
3. Hazard from polystyrene foam No. 2 - hazardous gas is released when ignited. Polystyrene foam should not burn, but when ignited, it begins to melt, releasing black smoke along with dangerous phosgene gas. Which causes paralysis of the respiratory tract.
Everyone has probably heard the tragedy that occurred in December 2009 in the Perm nightclub “Lame Horse”. According to one version, the cause of death was phosgene gas. Suspended ceiling the club was lined with foam plastic. When burning, the polystyrene foam produced suffocating smoke and gas emissions, which caused the death of people.
Doing insulating the house with polystyrene foam these two dangers must be kept in mind. I recommend that you avoid insulating the ceiling and walls with foam plastic indoors. When insulating the facade of a house, the insulation technology must not be violated. Around openings it is best to use basalt mineral insulation, which is a non-flammable material. And most importantly, foam plastic must have appropriate certificates. Do not buy from small and unknown companies, the likelihood of handicraft production is high, and control over the quality of the foam leaves much to be desired.
IN time of crisis the low cost of a wet facade is its main advantage. But if the facade does not last long, this advantage can be ignored: at the time of construction, the facade will be cheaper, but frequent restorations and complete alterations will “eat up” all the savings.
How many years does a wet façade last and how can its life be extended to the maximum?
Durability of a wet façade
This type of facade consists of several functional layers:
- insulation;
- reinforcing mesh;
- leveling plaster;
- priming;
- decorative plaster;
- If the plaster is not tinted, coloring is added.
Those. the system is both thermally insulating and decorative cladding walls
note
The service life of a wet facade is up to 25 years.
In practice this depends on the following factors:
- Type of materials, their quality. One of the priority issues when drawing up a project is its cost, but savings can affect durability. For example, the most affordable decorative plaster is cement (mineral). She has many advantages, but she serves half as long as the others.
- Material compatibility. It is recommended not to buy them separately, but to purchase a ready-made system in which insulation, plasters, primers, etc. are selected. according to their characteristics. In particular, on facades made of mineral wool it is not recommended to use plaster on acrylic base, on polystyrene foam - silicate. The fiberglass mesh must be alkali-resistant (this applies to all systems), the soil is also selected in accordance with the brand of insulation and plaster.
- Compliance with installation technology. The layers are laid in a certain sequence. Violation of this sequence will lead to rapid wear and destruction of the facade. Necessary step– additional mechanical fastening of the insulation (plus the adhesive one). The second important condition is compliance temperature regime: a wet façade should be installed only at above-zero temperatures; during installation, it should be protected from direct rays, rain and wind. If circumstances force work to be done in winter, an artificial microclimate is created around the house (thermal insulation circuit, in professional slang “warmhouse”).
- The right time. It is better to install wet facades after the house has settled. Plaster is the most sensitive; it can crack during the shrinkage process. In such cases, it is better to choose elastic types, but they are more expensive than cement-based plasters.
In addition to materials and technology, the durability of a wet facade also depends on external factors– temperature and humidity during operation. Sudden temperature changes accelerate wear.
Heading
In regions with mild climates, the facade will last longer.
IN harsh conditions Heavy wet façade technology is often used - as opposed to the so-called light façade, which is widespread in private and standard buildings in the middle zone. Heavy facades differ from light ones in the absence of an adhesive layer between the insulation and the base. Thermal insulation boards are attached to the wall and the reinforcing mesh to the boards using reinforced mechanical fasteners, and a thick layer of plaster is placed on top of this structure. Thus, the susceptibility of the system to temperature fluctuations is reduced (the most sensitive layers are the binders), and the resistance to shrinkage and cracking during movement increases.
This technology is used not only far north, but also in seismically hazardous areas, as well as at critical facilities, where the requirements for strength and wear resistance are higher. Such systems are more expensive than conventional lungs. This is partly compensated by more simple installation: installation of thermal insulation material using a glueless method does not require thorough removal of the surface.
Service life of different types of wet facades
Let's consider the longevity features of different facades:
- the actual service life of a wet polystyrene foam façade is about 15 years. Less than similar systems made of mineral wool and expanded polystyrene. This is explained by the fact that polystyrene foam has open pores. The vapor permeability of PPS group insulation is low; vapors that get inside are not removed. During the process of seasonal freezing and thawing, the material is gradually destroyed;
- The service life of a wet bark beetle facade depends on what kind of plaster was used. Mineral has the lowest durability (10 years). For acrylic - 20 years, silicone and silicate - 25 years;
- the durability of the Ceresit wet façade depends on the materials specific system. The service life of mineral wool facades (marked WM) is up to 25 years, polystyrene foam (VWS) is somewhat shorter - up to 20 years, due to the lack of vapor permeability of the insulation and plasters compatible with it.
The Gosstroy warranty period for wet facades applies to Ceresit systems and a number of others.
To the question “what is polystyrene foam?” there is a short and concise answer. Polystyrene foam (insulation) is a modern, environmentally friendly pure material, which is made from substances that cannot harm humans.
1 Features of the material
Foiled polystyrene foam, like its other analogues, can be used in places where other types of thermal insulation materials cannot be used due to the fact that capillary rise of groundwater can occur there.
Thus, the use of expanded polystyrene is due to the protection of waterproofing from environmental factors that can cause irreparable harm to it.
The presented material has its own GOST. GOST 15588-86 (it is made according to it) regulates the composition, properties and use of expanded polystyrene.
If you compare the presented insulation with a material such as mineral wool, then it is better to prefer the first.
Expanded polystyrene - warmth insulating material for walls
The fact is that mineral wool does not have such a spectrum useful characteristics, although in some respects it is still better than polystyrene foam.
In addition, mineral wool is a non-flammable material and is not capable of causing harm to human health. All this is indicated in the corresponding GOST.
It is best to first pay attention to the moisture-resistant characteristics of polystyrene foam, which are combined with its lightness, reliability and durability.
When choosing insulation, it is best to give preference to expanded polystyrene, since these products are not as heavy as mineral wool and are characterized by a high degree of ease of installation.
Externally, this insulation is presented in the form of small granules that are sintered together under the influence of high temperatures. GOST 15588-86 strictly regulates the size of granules of the substance.
Their size ranges from 1 to 10 mm and may depend on the intended purpose and the desired density of the product.
GOST also states that polystyrene foam granules may be heterogeneous in structure.
Each granule contains a huge number of thin-walled microscopic cells. This greatly increases the area of contact between the substance and the air.
The presented foam insulation consists of 98% air, which is why it unique properties. Reviews about this material are mostly positive; in addition to its excellent heat-insulating properties, it is often mentioned that it cannot cause harm to the human body.
1.1 Areas of application of expanded polystyrene
The presented material, due to its outstanding technical and operational characteristics in construction industry used almost everywhere.
Foamed polystyrene can be used as an insulating material. In addition, the product can successfully perform the function of a filler.
In some cases, polystyrene foam can even help solve problems associated with poor soil quality.
It can be applied to form embankments during construction road surface or bridges.
Expanded polystyrene PSB-S-35 2000×1000x180
2 Properties of polystyrene foam
The presented material has a fairly low thermal conductivity. Thus, expanded polystyrene is an almost ideal insulation material that can provide high heat conservation capabilities.
This feature is explained by the structure of the material, which consists almost entirely of air.
The thermal conductivity coefficient of a substance can vary between 0.032 and 0.043 W/(m∙K).
This figure is many times lower than that of wood, brick, expanded clay and other insulating building materials.
Low level of thermal conductivity affects the ability high level energy supply.
The use of expanded polystyrene as a heat insulator during the construction of buildings allows for its further operation to significantly reduce costs associated with heating.
High energy-saving properties allow the product to be actively used to protect pipelines from excessive freezing.
The presented substance provides reliable soundproofing protection against impact noise. This effect is directly related to the ability of a substance to convert sound energy into heat energy.
Based on this, thanks to the cellular structure of polystyrene foam, the presented material has effective sound-absorbing qualities.
It is worth noting that the material has a high degree of structural stability, fluctuating over a wide temperature range.
At the same time, low temperatures are not able to influence the mechanical, chemical and physical parameters of the substance.
When the temperature increases to +90°C, even during prolonged exposure, foamed polystyrene will not radically change its properties.
Due to the fact that polystyrene foam is completely synthetic, it is not perceived as food by insects and microorganisms, which does not contribute to their reproduction.
This material is absolutely unsuitable for bacteria or harmful fungi to survive in it.
The presented product is characterized by high resistance to water vapor diffusion and an increased moisture resistance coefficient.
Products cannot be dissolved in water and are not able to absorb it. Thus, the insulation is not subject to deformation and swelling.
This high degree of resistance to moisture means that foam products can be used to... This is especially true in situations where the insulating material is in close contact with the ground.
It is worth noting that the density of polystyrene foam products is quite low and equals 15-50 kg/m³, however, along with this, the substance has high compressive, tensile and bending strength.
This facilitates the use of the product as a durable building material, which is able to withstand mechanical load for a long time without being subject to deformation. Thus, due to the relatively small mass of the rearranged material, it is possible:
- Do not use special equipment when moving products;
- Reduce construction costs;
- Significantly reduce the installation time of structures.
In fact, polystyrene foam elements are plastic, and therefore, when correct operation, the material is able to retain its physical properties unchanged for a long time.
It is worth noting that foam granules consist of carbon and hydrogen molecules. This determines the high degree of environmental purity of the material.
Polystyrene foam does not exhibit toxic properties, does not generate dust and is not odorless.
Toxic substances are also not released from it. This insulation allows air to pass through quite easily, and therefore all structures in which it is included “breathe.”
Foam blocks can be easily pre-treated and do not irritate the skin and mucous membranes
As mentioned above, reviews of polystyrene foam are mostly positive.
Vitaly, 38 years old, Kaluga:
I decided to start insulating the apartment and start with the loggia. Polystyrene foam was used as insulation material. Excellent cutting and installation. I advise you to use it.
Sergey, 54 years old, Vologda:
I have an outbuilding in the courtyard of a private house. I decided to insulate its walls in order to live in it until late autumn. I used polystyrene foam boards. Now the heat stays inside very well. I recommend this material to everyone.
Vasily, 35 years old, Voronezh
I am engaged in the sale of insulation and building materials. Customers take the expanded polystyrene off the counter almost immediately. Everyone is very happy with him.
2.1 What is better to choose: polystyrene foam or mineral wool?
Mineral wool definitely loses to foam plastic in terms of thermal insulation properties. The thermal conductivity of polystyrene foam is much better.
However, mineral wool has excellent fire safety characteristics. This product has a high degree of fire resistance.
Polystyrene foam does not have such stability. The level of thermal conductivity of polystyrene foam is high and mineral wool is significantly inferior to it.
Mineral wool has a high degree of resistance to spontaneous combustion. Characteristics of vapor permeability mineral wool significantly exceeds this parameter of its competitor.
Along with this, polystyrene foam has a very high degree of hygroscopicity, therefore foam plastic can be used in environments with a high degree of humidity and is characterized by low cost.
The convenience of polystyrene foam lies in the fact that its weight is several times less than the weight of mineral wool, in addition, this material can be processed with an ease that is not possible when processing mineral wool.
There is one drawback - polystyrene foam boards have some difficulty joining each other. On the other hand, mineral wool has a high degree of resistance to almost all types of organic substances and fungi.
Along with this, polystyrene foam is significantly susceptible to all kinds of organic solvents, but fungi and mold do not take root on it.
Obviously, the process of choosing insulation is a complex and multifaceted task. In order to solve it with a high degree of efficiency, it is necessary to carefully take into account the current conditions and your own priorities, including.
It is important to give preference only to well-tested heating systems. We must also remember correct selection most optimal thickness thermal insulation material.
Mineral wool can easily pass moisture through itself. This indicates that this material is indispensable when insulating a house built of wood or beams.
It is important to remember that under a layer of polystyrene foam the wood quickly rots. In this case, you should first take care of installing the so-called parabarrier, and then secure the sheathing.
Mineral slabs, in most cases, are laid in two layers. This is done to prevent the creation of so-called “cold bridges”.
The material is covered with a film on top that provides waterproofing. When insulating a balcony, preference is almost always given to polystyrene foam since during installation there is no need to use lathing, which has a positive effect on saving balcony space.
You should immediately pay attention to the fact that the selected insulation must necessarily correspond to the climatic conditions in which it is used.
2.2 Pros and cons of polystyrene foam (video)
This article questions the mass advertising material about the remarkable properties of expanded polystyrene, its durability, fire and environmental safety. Unfortunately, the unsubstantiated and broadcast advertising of the properties of polystyrene foam is not confirmed in any way scientific research, analysis and test results. The proposed material summarizes the research of scientists on one of the most commonly used thermal insulation materials for thermal insulation of buildings—expanded polystyrene.
Manufacturers of expanded polystyrene and those who promote its widespread use want the consumer not to know that irreparable things happen to expanded polystyrene over time. They do not care about the condition of the external insulation of buildings after the end of the warranty period.
Review of the article by Batalin B.S. and Evseeva L.D. “The performance properties of expanded polystyrene are of concern.”
Reviewed article by Batalin B.S. And Evseeva L.D. is of interest to a wide range of builders and scientific workers. Expanded polystyrene how thermal insulation material has become most widespread in recent years and is widely used in construction practice. The authors of the article conducted in-depth studies of the properties of expanded polystyrene and summarized a large number of works performed by other scientists in this field. They do not dispute the merits of expanded polystyrene as a highly effective thermal insulation material. At the same time, the authors of the article give a tough and fair assessment of its negative properties, which include fragility, fire hazard and environmental hazard. Reviewer having personal experience in the field of durability of building materials, I agree with this assessment of the authors. IN different time Many experts on the durability of building materials and structures worked at the Research Institute of Building Physics and also noted that the durability of this material and other heat-insulating materials, as a rule, does not exceed 30 years.
The following fact is indisputable: when burned, polystyrene foam releases substances harmful to humans, which lead to death.
Head Laboratory of Thermophysics and Construction Climatology NIISF Doctor of Technical Sciences, Prof. VC. Savin
Work on thermal insulation of buildings in a country with a cold climate is quite expensive. During a crisis, everyone is trying to save money and use cheaper materials, especially when it comes to the construction of social housing. The notorious fire in the Perm club “Lame Horse” claimed the lives of 155 people, largely thanks to expanded polystyrene, an analogue of mineral wool insulation. The cause of death for most people was poisoning from combustion products. As it turned out, soundproofing material the club had expanded polystyrene (foam) boards. Initially, polystyrene foam was used as a packaging material, then someone came up with the idea of using it as insulation for residential premises...
Boris Semenovich BATALIN, expert of the Center for Independent Forensic Examinations REF "TEKHEKO", Doctor of Technical Sciences, Professor of the Department of Building Materials and Special Technologies of the Perm State Technical University, full member of MANEB and RAE and Lev Davidovich EVSEEV, Doctor of Technical Sciences, member of the Expert Council on Heat soundproofing materials under the Administration of the President of the Russian Federation, Chairman of the Commission on Energy Saving in Construction of the Russian Society of Construction Engineers (Samara Branch), Member of the RSPP Committee on Technical Regulation, Standardization and Conformity Assessment, Advisor to the RAASN, Honorary Builder in their research question the widely advertised properties of polystyrene foam insulation.
Wasteful by nature
As is known, up to 70% of the thermal energy received by a building is released into the atmosphere. In the 70s of the last century, this was known to space reconnaissance specialists taking photographs. earth's surface in a special way. Cities of the Soviet Union “glowed” in infrared rays in winter and summer, day and night. The opposite picture was observed when photographing cities in Western Europe, the USA, Canada and other countries.
Conclusion:
We are wasteful beyond our means: our houses, heating mains, industrial premises literally warm the atmosphere. If in the USA heat loss per square meter of housing is, on average, 30 Gigacalories, and in Germany - from 40 to 60, then in Russia - about 600!
When the first global energy crisis occurred in the mid-seventies of the last century, large-scale work began in many countries to increase the level of thermal protection of buildings. In practice, up to 70% of the thermal energy from each building and up to 40% of the thermal energy from the pipelines goes into the atmosphere. Thus, out of 10 railway cars of coal, seven are transported only to “heat the street”!
Such losses of thermal energy could not be tolerated in the future, especially during the transition to market relations: to combat heat losses in Russia, the federal law“On energy saving”, as well as the development and introduction of Appendix No. 3 to SNiP II-3-79 “Construction heating engineering”.
The latest regulatory document was later transformed into SNiP 23-02-03 “Thermal protection of buildings”.
Introduction of new regulatory requirements for thermal protection of external enclosing structures resulted in a significant increase in the standardized heat transfer resistance of enclosing structures (R0) from 0.9 to 3.19 m2°C/W in Samara region. A similar increase in the standardized heat transfer resistance occurred in all regions of the country. The conditions of the second stage (from 2000) provided for an increase in the value of these requirements by 3.5 times (!). True, in many regions of the country territorial certificates were subsequently issued building codes, which allowed R0 to increase only 1.8-2.2 times for middle zone Russia. The same requirements are reflected in STO 00044807-001-2006 Standard of the organization “Thermal insulation properties of building envelopes” (issued in accordance with the Federal Law “On Technical Regulation” and put into effect on March 1, 2006).
The introduction of new requirements for thermal protection of buildings has led to the widespread use of various thermal insulation materials. The largest niche - up to 80% - was occupied by the currently most common thermal insulation material - expanded polystyrene, which is one of the representatives of the foam class. Many enterprises producing expanded polystyrene (often using artisanal methods) have appeared in the country. This material began to be used both for external thermal insulation enclosing structures of buildings, and from the inside, including when using well and layered masonry.
All types of expanded polystyrene - non-pressed, pressed, extruded - have the same chemical composition of the main polymer - polystyrene and may differ in chemical composition only additives: blowing agents, plasticizers, fire retardants, etc.
As a rule, with the pressless manufacturing method polystyrene foam boards a lower density of the thermal insulation material is obtained, on average 17 kg/m3. With the pressing method and the extrusion method, polystyrene foam boards have a density of 35-70 kg/m3.
Negativity is hushed up
The widespread use of expanded polystyrene in everyday construction practice for thermal insulation of walls from the inside has led to the rapid accumulation of moisture between the enclosing structure and the insulation, to the appearance of mold fungi, and subsequently to the illness of people living in such houses. Numerous complaints in connection with the formation of mold fungi initiated the sending to all regions of a letter (out. No. 24-10-4/367 dated March 5, 2003) from the head of the Glavexpertiza of the Russian Federation with the following content:
“... insulation of external walls with inside slab or roll insulation is categorically unacceptable, since such solutions cause accelerated destruction of enclosing structures due to their complete freezing and expansion of microcracks and seams, and also lead to the formation of condensation and, accordingly, to soaking of walls, floors, electrical wiring, finishing elements and the insulation itself.”
A similar situation is observed with external thermal insulation of buildings or when using well masonry, which is reflected in various research materials published in the press.
The purpose of this article is not to explore various constructive solutions using expanded polystyrene, and to familiarize a wide range of readers with the results of studies of the properties of this currently popular insulation, carried out by independent researchers. Today in the media, polystyrene foam manufacturers are conducting a massive advertising campaign in defense of their product. What wonderful qualities this material is endowed with: the highest thermal insulation properties, fire safety, durability (you don’t have to worry about 50-70 years), environmental safety, etc.
Unfortunately, in scientific literature it is impossible to find confirmation of most of these properties. Information about the properties of expanded polystyrene has been published by researchers in scientific and technical publications for many years and is discussed on round tables. Manufacturers of polystyrene foam do not dispute this truthful information, but supplement it with a saying: “The average consumer should not know the whole truth.”
We consider it immoral when a customer, buying polystyrene foam and using it in the construction of buildings or for insulating residential premises, is deprived complete information about the negative properties of the thermal insulation material widely used in the country. After all, this is a direct violation of the Constitution of the Russian Federation, Article 42 of which states: “Everyone has the right to favorable environment, reliable information about her condition and for compensation for damage caused to his health and property by an environmental violation,” and the Civil Code is based on “the need for the unhindered exercise of civil rights” (Article 1).
Why is polystyrene foam harmful?
Expanded polystyrene, like its analogues, is subject to destruction within a short time under the influence of atmospheric oxygen even at normal temperatures, gives a significant excess of the concentration of toxic substances above the maximum permissible concentration, high content of toxic organic compounds in the smoke during a fire, it is characterized by fragility (significantly below the lifespan). building services) and fire hazard.
The main disadvantage of expanded polystyrene is its poor knowledge as a building material.
The decision on the possibility of using polystyrene foam remains, as always, with the buyer or customer. But they should know what the future may hold when using expanded polystyrene. It should be noted that the thermal insulation properties of polystyrene foam are quite good when tested immediately after its manufacture. But this is where all the advantages of this material end.
Expanded polystyrene has three integral negative properties, emanating from its nature, which must be treated simply with caution, with an understanding of these processes. Firstly, there is a fire hazard. Secondly, it is fragility. And thirdly - environmental unsafety. These properties require additional research.
Some manufacturers of expanded polystyrene are wrong, who believe that by making information about the properties of expanded polystyrene public, scientists will cause damage business reputation these enterprises.
In advertising and information publications devoted to expanded polystyrene, their authors, describing the fire-technical properties of these materials, are to a certain extent disingenuous, claiming that expanded polystyrene certain types do not burn or go out on their own. Note: this behavior of these materials does not yet indicate their fire safety. The fact is that, according to the standard methodology, when qualifying building materials for fire danger experimenters take into account the loss of their mass when heated in air. Therefore, in accordance with the official classification of building materials by fire hazard, all polystyrene foam without exception belongs to the class of combustible materials.
In practice, the problem of fire hazard of polystyrene foam is usually considered from two points of view: the danger of the actual combustion of the material and the danger of the products of its thermal decomposition and oxidation. The main damaging factor of fires, as is known, are volatile combustion products. As practice shows, on average, only 18% of people in a fire die from burns, the rest from poisoning in combination with the effects of stress, heat and other damaging factors. Statistics show that even with relatively small fire in a saturated room polymer materials, there is a rapid death of the people there, mainly from poisoning with toxic volatile products.
Research by the Russian Research Center for Fire Safety VNIIPO of the Ministry of Internal Affairs of the Russian Federation, presented on the website www.aab.ru/sertif, clearly indicates the high fire hazard of foam plastics. For example, in the above report on the fire hazard tests of polystyrene foam, it is indicated that the toxicity value of the samples close to the limit value of the class of highly hazardous materials.
These facts, known in the specialized literature, periodically materialize in more and more specific examples, reflected in the means mass media. For example, in the newspaper “Local Time” (Lerina N. Quality of Safety. Perm, No. 4, 2001, p. 7) an example of a fire in a residential building is given. The author writes: “A woman died during the fire. The paradox of the situation is that the fire occurred in an apartment located two floors below. The cause of death was toxic polystyrene foam smoke.”
In a report shown on Yekaterinburg television (E. Savitskaya, M. Poptsov. TV company ASV. Fire in a house under construction), it was said that “the thermal covering made of polystyrene foam caught fire... During the fire, the corpses of two men were discovered. They were lying two floors above the source of the fire with signs of smoke inhalation.” The authors claim that “the firefighters were interested in polystyrene insulation, which burned in large quantities and caused this black choking smoke.”
Obviously, one of the main dangers that arises when using polystyrene foam for insulating residential buildings is that it is a flammable material that has high toxicity and smoke-generating ability. In addition, the combustion products of polystyrene foam seriously poison the environment even at a great distance from the fire site.
The thickness of the polystyrene foam insulation layer is also important. In some European countries, the thickness of the thermal insulation layer made of polystyrene foam does not exceed 3.5 cm. After all, what thinner layer combustible thermal insulation, the safer it is in terms of fire. In our country, in many systems, the thermal insulation layer of polystyrene foam reaches 10-30 cm.
From a scientific point of view
To understand the advantages of the material, it is necessary to consider the properties of expanded polystyrene from the point of view of physical chemistry. This is how A.A. characterizes these properties. Ketov, professor-chemist of Perm Technical University, member of the expert council of the regional Committee for Nature Conservation.
“First of all, by definition, foam plastics are dispersed polymer systems. Therefore, it is inevitable that foam plastics are not only organic compounds, but also have a very high contact surface with atmospheric oxygen. It is known from a chemistry course that the possibility of a reaction is determined by the Gibbs energy... In other words, if an organic compound is in air, then it will inevitably oxidize oxygen. Moreover, since foam plastics inevitably have the maximum possible surface, they will oxidize at the maximum speed compared to similar, but monolithic massive polymers. Therefore, for any foam plastic, it is inevitable to assume a certain finite and very limited operating time, when its operational properties will still be in permissible limits. Naturally, with increasing temperature the rate of oxidation will only increase. Therefore, all foam plastics are fire hazardous materials. And finally, if foam plastics inevitably oxidize even at room temperatures, then the products of such oxidation have a negative impact on the environment. It is obviously inappropriate to discuss this “harmful” pattern, since the law of nature does not depend on our opinion. If we cannot resist it, then there is one way: to circumvent this law, that is, to find means of protection against toxic secretions.
And this will definitely have to be done, since millions of people already live in apartments insulated with polystyrene foam. Expanded polystyrene under natural operation conditions in the air (with temperature fluctuations from minus 30 to plus 30°C, absence of light and direct exposure to precipitation) undergoes chemical interaction with oxygen from air
spirit. At the same time, benzene, toluene, ethylbenzene, as well as acetophenone, formaldehyde and methyl alcohol are released into the environment. In addition, to the environment, especially in initial period operation, styrene is released as a consequence of incomplete polymerization and depolymerization products. Exceeding the concentration over the maximum permissible concentration according to the State Institution “Republican Scientific and Practical Center of Hygiene” (Republic of Belarus) only for styrene different manufacturers at a temperature of 80°C is from 22 to 525 times (!), at 20°C - from 3.5 to 66.5 times (!).
The paradox is that from the point of view of thermophysics, polymer insulation materials are indeed the most effective heat insulators. There's no point in denying it. But when it comes to housing, about such a product construction production, with which a person will have to communicate for many hours every day for decades - here, even the most fantastic thermophysical properties are too few. The main thing here is safety, durability, and maintainability.
The construction market, overcoming inertia, is already beginning to respond to devastating publications about the negative features of polystyrene foam insulation and to look for an adequate replacement for the dangerous material. What's happening in the Samara region? The main supplier of expanded polystyrene is one of the Samara enterprises, which mainly produces expanded polystyrene grade 25, that is, with a density from 15.1 to 25.0 kg/m3. Despite the recommendations of the normative document SP 12-101-98, the 1982 edition of SNiP for construction heating engineering on the use of expanded polystyrene with a density of at least 40 kg/m3, design organizations To please the customer they write “brand 25”. An incompetent person thinks straight: “grade 25” means density 25 kg/m3. However, in technical specifications, “grade 25” corresponds to a density from 15.1 to 25.0 kg/m3. Naturally, the manufacturer, when applying for “grade 25”, will provide polystyrene foam of the lowest density - 15.1 kg/m3, since in this case this enterprise will have the maximum profit. Thus, low-density polystyrene foam, that is, the density of packaging polystyrene foam, legally enters the construction site. What this leads to is already noticeable on the facades of buildings insulated with polystyrene foam - mold appears, fungus and wet spots appear.
Doesn’t every consumer have the right to know about changes in the performance properties of expanded polystyrene over time, about the destruction of this material? After all, today he pays significant sums to buy an apartment, a cottage and hopes that this property will serve him all his life and will be inherited by his children and grandchildren. The consumer should know that, according to the classic Encyclopedia of Polymers, over time, “destruction of polymers occurs—the destruction of macromolecules under the influence of heat, oxygen, light, penetrating radiation, mechanical stress, biological and other factors. As a result of destruction, it decreases molecular mass polymer, its structure, physical and mechanical properties, the polymer becomes unsuitable for practical use.”
Thus, in air at ordinary temperatures there is a mandatory change chemical structure polymers under the influence of atmospheric oxygen, called oxidative destruction.
The purpose of the government's decision to insulate building envelopes is to save thermal energy. However, after more than ten years of savings (since 1996), many builders have come to the conclusion that, in fact, due to the incompetent use of insulation, savings are not happening. Moreover, when using some
systems, mainly using polystyrene foam, is arranged between the wall and the insulation air gap, and the wall during operation becomes not heat-insulating, but, on the contrary, heat-conducting. The fact is that with some insulation methods, the wall is a physically heterogeneous body. The “thermal insulation cake” often consists of 7-8 materials of different nature. Inside it, an interface appears between materials with different vapor permeability. Moisture (water!) begins to accumulate on this surface. Water impregnates a denser material, and its thermal conductivity increases greatly. Condensation forms in the air voids between the wall and the insulating material. With such a low thermal resistance, there is virtually no thermal protection. And all the previously obtained heat savings are now “eaten up” by increased heat consumption to maintain a comfortable standard temperature in the room.
We're losing money!
The results of a survey of buildings with external walls insulated with expanded polystyrene show that this thermal insulation material has a number of physical and chemical features, which are not taken into account by designers, builders and services responsible for the operation of buildings and structures. As a result, our country suffers large material costs. One of the typical examples, as the director notes scientific center ROIS, Doctor of Technical Sciences A.I. Ananyev, could serve as an underground shopping complex built in Moscow on Manezhnaya Square, where mistakes were made not only during the development of the project for covering the complex, but also during the execution of construction work. As a result, after just 2 years of operation, the coating had to be overhauled with almost complete replacement of polystyrene foam thermal insulation boards. The main reason for the mistakes made is the lack of necessary information in the scientific and technical literature on the behavior of expanded polystyrene in structures and changes in its heat-shielding properties over time. This is confirmed by the wide range of service life unreasonably set by manufacturers in the range from 15 to 60 years for polystyrene foam.
At the same time, there is no officially approved method for determining the durability of polystyrene foam boards and enclosing structures using it. The main obstacle in its development is the unusual behavior of polystyrene foam under operating conditions. For example, the stability of its thermophysical characteristics over time largely depends on the manufacturing technology and compatibility with other building materials in wall and coating structures. It is impossible not to take into account the influence of a number of random operational factors that accelerate the natural process of destruction of polystyrene foam. Even the behavior of polystyrene foam in a fire significantly distinguishes it from other thermal insulation materials.
It has been established that the strength of samples taken from the walls of buildings in use is somewhat lower than that of samples taken directly from the factory. At the same time, it is very difficult to assess how the density of used samples has changed due to the lack of primary data corresponding to the time the buildings were put into operation. The decrease in the strength of the samples over time of operation was more significant when the density of polystyrene foam was below 40 kg/m3. Cases have been recorded when the values of the thermal conductivity coefficients of expanded polystyrene over 7-10 years of operation of structures increased by 2-3 times. This is usually associated with a violation of technological regulations during construction work or the use of materials incompatible with polystyrene foam, as well as the use of paints containing volatile hydrocarbon compounds to repair walls.
Magazine "Construction Expert", No. 09-10 (306), 2010
The problem of insulating a private house or apartment has always had to be solved, while effective ways arose only after the advent of such building materials as polystyrene foam. Insulating the ceiling, floor and walls with its help allows you to retain heat in your home and at the same time save money.
Polystyrene foam
There is pressed and non-pressed foam; it is not too difficult to distinguish them, even if you are not a professional. If you have ever looked at the structure of a material, you have most likely noticed that it consists of small balls that are interconnected, like a honeycomb in a beehive.
Pressless foam can be seen in boxes with household appliances, since it is actively used for packaging.
By thermal insulation properties And appearance the pressed one is practically no different from the second one, its granules adhere to each other somewhat more firmly, due to which it does not crumble. At the same time, pressed foam is more difficult to produce, which means it is more expensive, which is why it is less widespread.
Technical characteristics of polystyrene foam
This breathable material has low specific gravity, does not accumulate moisture, and is not subject to rotting. Its main drawback is its flammability, although by applying plaster the home can be protected from fire.
Polystyrene foam characteristics:
- biological and chemical resistance to sea water, alkali, salt, soap, cement, bitumen, lime, gypsum;
- low thermal conductivity;
- resistance to temperature changes, due to which the material can be used in different climatic conditions;
- he is not favorable environment for the development of fungi, mold and microorganisms;
- high vapor permeability - thanks to it, the moisture that accumulates in the walls evaporates;
- excellent soundproofing properties.
Basic properties of polystyrene foam as insulation
Expanded polystyrene is popularly called “foam plastic”. This word comes from the name of a Finnish company that supplied expanded polystyrene to the USSR. The name of the company was transformed over time into the name of this material.
At the moment, foam plastic is produced abroad and in Russia by various companies. The equipment for its production is cheap, and does not require skilled labor for maintenance and operation.
Now let's look at the properties of polystyrene foam:
Now let's move on to the use of polystyrene foam in low-rise private construction.
Foam insulation: simple and easy
It is done very simply. The polystyrene foam is attached to the wall of the building using special screws. Initially, you can level the wall using putty, attach the slab, then apply a layer of putty again and paint it. This way you get a completely flat wall.
Insulation of buildings from outside
Polystyrene foam as wall insulation is most often used outside. This method makes it possible to move the freezing point to the outer part of the wall, while preventing the cold from penetrating inside.
For this purpose, sheets with a thickness of 100 millimeters are used. They are attached using dowels and special glue. Performing these works at height is only possible using special equipment.
Internal insulation of the room
This method is less common than the previous one, although it is also effective. It is very convenient that it can be implemented regardless of the time of year and weather. But before insulating the walls inside, they must be pre-treated with special anti-mold compounds.
It should be taken into account that polystyrene foam as insulation reduces the usable area of the room. This is explained by the fact that it takes up quite a lot of space, especially considering that drywall is attached to the top.
Insulation of building walls
This method is applicable in the construction of 1- and 2-story houses. A wall 250 mm thick is erected, then foam plastic sheets are laid, which are protected plastic film, then the inner wall. This method has the advantage that polystyrene foam as wall insulation is completely protected from exposure open fire and mechanical damage.
Insulation of floors
If we consider polystyrene foam as a floor insulation (reviews about this use can be seen mostly positive), it is important to take into account that its sheets are laid in cement-sand liquid solution while performing the screed. Air bubbles are expelled using vibration. A 50 mm screed is also made on top of the material.
These measures are especially necessary for residential buildings with damp basements. But in middle-floor apartments, foam plastic as floor insulation will also provide good sound insulation. In addition, this procedure is performed when laying a water-heated floor.
Insulation of ceilings
Such insulation is performed in the same way as with walls. The difference lies in the thickness of the sheets used: it should be no more than 50 mm. In a typical residential building, most apartments have low ceiling heights. Of course, if possible, you can increase the thickness of the foam.
This measure allows you to insulate the apartment, while reducing the noise level and making the home more comfortable.
Basement insulation with foam plastic
It will not be possible to use polystyrene foam in this case due to its hygroscopicity. At the same time, its thermal conductivity increases sharply, and its thermal insulation greatly decreases.
When polystyrene foam in autumn and spring period gets wet, the water in it turns into ice when it freezes, after which it breaks the material. After the first frost, wet polystyrene foam turns into dust, turning into separate balls that are unable to retain heat.
Base insulation with polystyrene foam
But for this it is quite possible to use this material. In this case, foam plastic as insulation is covered with a layer of plaster on top. The foam is attached to the base using plastic “fungi”, to which a fine metal mesh is then attached. Then plaster is applied to it and a decorative layer is applied on top - clinker brick, wild stone, facade tiles.
In this case, you can also use a metal profile for plaster to attach the foam. In this case, it is advisable to abandon the use of a system of wooden blocks. Practice shows that concrete base When the base is finished, the wooden blocks begin to rot from below, and moisture also gains access to the insulation.
Foam plastic for insulation of a wet facade system
On the facade of the house, the place of foam plastic is located under a layer of continuous decorative non-combustible coatings and plaster. When there is no access to oxygen and open fire, and there is no direct exposure to moisture, this material exhibits its best properties. Don’t forget about the reasonable cost, low thermal conductivity, and light weight.
Roof insulation
Here you need to understand where and what width of material to use. The “non-ventilated roof” is covered with 70 mm thick foam plastic, then a bitumen waterproof layer is laid on its surface. “Ventilated roof” involves installing slabs on the back side of the roof, while the ventilated cavity remains, preventing condensation.
Attic spaces can be great living rooms. At the same time, thermal insulation gable roof brings great benefits at low cost. To do this, you need to install foam plastic in the cracks between the rafters.
Thermal insulation of pipelines
Until recently, thermal insulation engineering communications was not given special significance, while due to them the share of heat loss is about 30%. For pipelines of ventilation ducts, cold water supply, buried cables and telephone lines, foam plastic is now increasingly being used as insulation. This material is also used to protect sewer and water pipes from freezing. The undoubted advantage of using polystyrene foam for these purposes is the ability to give this material various shapes.
Where is it prohibited to use polystyrene foam as insulation?
- Expanded polystyrene cannot be used when insulating a bathhouse, since increased humidity and heating result in the emission of styrene.
- There is no need to insulate window slopes from the inside - for this it is advisable to use polyurethane foam. This material is more suitable for insulating rooms from the inside.
- It is dangerous to use this material when insulating interior spaces when a system of wooden or metal profiles and further cladding with various decorative materials are used.
It is important to know
Laying foam sheets directly on the ground is not allowed: you must first waterproofing works, then pour a layer of screed. Otherwise, the floor may be damaged by rodents.
If all rules of use are followed, the service life of foam plastic as insulation reaches 100 years. This is its undoubted advantage.
Compliance with the rules for using polystyrene foam as insulation makes it possible to save money on heating your home, and also get rid of excess noise. It can also protect from the sun's hot rays, while preventing the outside walls from heating up. Therefore, there is no need to regularly use the air conditioner, which allows you to save on electricity.