Expanded polystyrene - characteristics and selection criteria. Foam insulation: food for thought Thermal insulation of engineering systems

Advantages of insulating the walls of a house with polystyrene foam. How to choose the right insulation. “Wet” façade technology.

We insulate the house with polystyrene foam

The annual rise in energy prices and the desire to live in a cozy, warm home force owners of individual real estate to quickly insulate their buildings.

The article tells you how to choose the right polystyrene foam and insulate the walls yourself, what tools and consumables you will need.

Advantages and disadvantages

Foamed polystyrene is a synthetic material whose positive properties make it an excellent insulation material. Advantages compared to other materials:

Small specific gravity. One cubic meter of foamed polystyrene weighs from 11 to 40 kg. This amount of material with a sheet thickness of 50 mm is enough to insulate 20 square meters. m. walls.
Insignificant price compared to other insulation materials.
Low thermal conductivity, which helps save energy during the heating season and keeps you cool in the summer.
High levels of noise insulation, providing comfortable conditions in houses located along busy streets.
Strength sufficient for mounting plates in a variety of ways.
Easy installation.
Available at any hardware store.

Among the shortcomings are noted:

low vapor permeability;
toxicity when heated;
necessity exterior finishing for protection from direct exposure to sunlight (foam is destroyed by ultraviolet radiation).

What are the parameters for choosing polystyrene foam?

When choosing polystyrene foam, take into account the physical specifications, which contribute to the performance of the functions assigned to the insulation:

preservation of heat (coolness);
ease of installation;
the chosen method of insulation;
environmental friendliness for nature and safety for human health.

Let's take a closer look at the characteristics.

Slab thickness

In stores you can find sheets with a thickness of 10 to 100 mm in increments of 10 mm. The choice of thickness depends on the region and purpose of the building. Sheets of 40, 50, 100 mm are in demand and most often found in retail outlets, but the manufacturer is ready to produce products of 20, 60, 70, 80 up to 500 mm to order. The price will remain the same, calculated per cubic meter.

To simplify understanding, on average, foamed polystyrene with a thickness of 10 cm retains heat in the same way as timber with a thickness of 45 cm, foam concrete masonry with a thickness of 73 cm, Brick wall 150 cm or concrete 300 cm. This is enough to insulate walls in any region of the country.

Size

It is more difficult to choose the length and width of the sheets. Accepted here standard sizes 500x1000, 1000x1000 and rarely 1000x2000 mm. For installing insulation around windows and doorways The sheets are cut with a sharp knife or a file with fine teeth.

For large objects, electric cutters are purchased and made independently - this way the material crumbles less and the edges remain smooth, which is convenient for further finishing.

Density

The main parameter characterizing the scope of application is density.

For use in construction, manufacturers produce products of three varieties, which are conventionally designated by numbers in the name - 15, 25, 35. Their brief Comparative characteristics is given in the table.

Table. Characteristics of different brands of polystyrene foam.

The low density of PSB-S-15 foam makes the sheets “loose” and easily destroyed. A small mechanical impact leads to damage and leaves dents.

If we compare thermal conductivity, then the values for different types foam polystyrene do not differ much, unlike the price, so it’s not worth overpaying “for density”.

Flammability

Polystyrene foam burns only when exposed to open flame. The damping time (self-combustion) is 3 – 4 seconds.

At the same time, when polystyrene foam burns, highly toxic substances are released, causing death from suffocation.

If a fire occurs, you should leave the premises immediately.

Is it possible to use polystyrene foam on concrete walls?

Another important characteristic of any insulation is vapor permeability.

Polystyrene almost does not allow vapor to pass from the room to the street, but for insulating concrete walls this does not matter, since the materials are similar in performance. If the premises of a brick or expanded clay concrete house are humid, properly arranged ventilation solves the problem.

It is not advisable to insulate concrete walls from the inside for permanent housing. In cold weather, the dew point (freezing point) will move closer to the inside, the walls will freeze to their entire thickness.

Internal insulation is beneficial for dachas that are not constantly heated. In this case, the building will warm up faster, since the house will become warm before the brick (stone, expanded clay concrete) walls warm up - the heat from the heating devices, like in a thermos, will be retained by the foam plastic.

Which is better - polystyrene foam or polystyrene foam?

Foam plastic - foamed polystyrene. The name expanded polystyrene is commonly understood as extruded polystyrene, produced under the brands PENOPLEX, TECHNOPLEX, URSA.

It has a higher density, the material is durable, and has grooves at the edges for a tight fit of the sheets. There is no crumbling when cutting, which reduces the amount of debris.

The price of extruded polystyrene is significantly higher than polystyrene foam, but the main characteristic of the materials - thermal conductivity - is comparable in terms of performance to PSB-25.

Among the advantages - the material is better resistant to moisture, which is important when insulating basements and ground floors. Installing penoplex on walls has no benefits compared to polystyrene foam.

Do-it-yourself technology for insulating external walls with polystyrene foam

A craftsman familiar with the basics of finishing work can insulate walls.

Let us consider in detail the insulation method called “wet facade”.

Tools

For work you will need hand and power tools:

level, plumb line, hammer, tape measure, pencil, hacksaw (knife), trowel and spatula;
bucket for stirring glue and plaster;
hammer drill or impact drill with bits or drills for concrete;
whisk attachments for drills for preparing solutions.

From consumables purchase:

glue for polystyrene on a cement or synthetic basis;
dowels with a rod length 4-5 cm greater than the thickness of the foam;
mounting foam or adhesive foam;
foam gun.

Work progress step by step

Wall insulation begins with preparatory work:

calculating the amount of insulation and its purchase;

You can calculate the area and amount of material by adding up the area of all external walls. When purchasing, add 5% to the calculations for possible errors during fitting and purchase 6-7 special dowels for each square meter at the joints of sheets at the outer corners of the walls.

preparing and checking instruments;
purchases of consumables;
installations scaffolding(if necessary).

The work is carried out in the following sequence:

The surface of the walls is prepared and cleaned of dust and dirt.
The voids in the seams (if any) are sealed cement mortar or foam.
Level the surface with plaster so that unevenness does not exceed 1.5 - 2 cm. This will make it easier to fit the sheets and reduce the amount of expensive glue during further finishing.
At a level of 50 cm from the ground, a support bar is attached strictly horizontally, if the foam is not placed to the ground, but finishing is provided with another material.
Using a level and plumb line, markings are made.
Apply a sheet according to the markings and through it (to avoid mistakes) drill a hole in the wall for the dowel.
Starting from the central hole, fix the sheet to the wall.

You can attach foam to a flat surface using only dowels. For fastening to poorly plastered walls, a layer of glue is applied to the material plates and pressed against the wall. For reliability, you can fasten the dowels after a day.

When installing the first row, the level is precisely maintained. This will help avoid gaps when installing subsequent slabs.

The second and subsequent sheets are placed offset (in a checkerboard pattern).
The seams are sealed with polyurethane foam. Remove excess sealant after complete hardening, usually after 12 hours and up to 24 hours.

Instead of polyurethane foam, it is better to use adhesive foam - it has a lower coefficient of secondary expansion and adheres sheets better.

Using a special toothed roller or other available means, punctures up to 0.5 - 1 cm deep are made on the surface of the foam for better adhesion to the layer of adhesive plaster.
A 1-2 mm layer of specialized polystyrene foam adhesive is applied to the foam, which is leveled with a spatula.
A fiberglass mesh is applied to the glue and “sunk in.” The joints are overlapped, overlapping by 10 cm. The seams between the sheets and the edges of the mesh should not coincide.
Level the glue with a spatula. By adding portions of glue in the right places, the final leveling of the surface is carried out, working as if using putty.

Finishing

After the composition has dried, prime the surface with products for external use.

The final finishing is carried out with facade paint or bark beetle plaster. The latter option is preferable, as it hides inaccuracies and irregularities, which are especially visible in side lighting.

At frame insulation There are no tricks. The foam is secured with wide-headed dowels between the frame slats. The remaining voids are filled with polyurethane foam or adhesive foam. Then, without fail, a waterproofing membrane is nailed to the frame. It is convenient to do this with counter-lattice bars, the thickness of which is 1-1.5 cm. After installing the siding or other material, there will be a gap between it and the foam, which will reduce the likelihood of dampening of the materials - the facade will become “ventilated”.

How long will it last

Foam plastic is resistant to moisture and aggressive substances of organic origin, so the service life before replacement is, according to manufacturers, 700 freeze-defrost cycles. This is significantly longer than the service life of the plaster layer, in which, in addition to the composition itself, the polymer mesh is destroyed.

Based on the recommended operating parameters, you can expect the service life of external foam insulation to be from 20 to 40 years. It all depends on the quality of the building materials and the careful work carried out.

Insulation of house walls with polystyrene foam is one of the available ways keep warm in winter and cool in summer. A simple installation process that anyone can master makes insulation with foamed polystyrene a popular method that allows significant savings on the purchase of materials and wages for builders.

Useful video

The most popular material for insulation of any buildings, both walls, floors and ceilings, in our time is extruded polystyrene foam insulation. But, like most other building materials, along with its advantages, it also has its disadvantages.

In this material we will try to analyze in as much detail as possible its strengths and weak sides. We’ll also tell you how to work with this material, following safety precautions. fire safety.

In everyday life, this material can be found under the name “foam plastic,” but this is fundamentally incorrect. These two materials are significantly different from each other. For example, extruded polystyrene foam (EPS) is one of the most deformation-resistant and durable varieties, and its heat-shielding properties are almost not affected by this.

High-strength EPS is produced on special production lines through chemical extrusion of the original raw material, which is pure polystyrene granules.

Using special equipment, raw materials are converted into foam, from which, in turn, small granules are produced. During the hardening process, these granules are pressed into layers of the required shapes and sizes, after which they can be used not only for insulating houses, but also for other purposes.

It is precisely due to its fine porosity that EPS is an order of magnitude more durable than ordinary polystyrene foam. Compressed under high pressure and high temperature Such granules give the material greater strength, hardness and reliability

The main difference between extruded polystyrene foam and pressed polystyrene is in the characteristics of its granules. They are smaller, which makes this building material more resistant to physical stress. Heat granule size insulating material produced by extrusion does not exceed 0.1 mm, while non-pressed granules can reach up to 10 mm.

In foreign interpretation, EPPS may be called XPS. It is produced in several varieties. After the abbreviation “XPS”, the markings of this material contain numbers from 25 to 45, which indicate its density.

The higher the value, the higher the density of the material. Particularly dense extruded material can even be used to insulate asphalt road surfaces, for example, the company's products.

Now that we have figured out what EPS is, we will discuss in detail all its pros and cons.

The main advantages of the material

In fact, polystyrene is the same plastic, only endowed with different qualities. But just because it is somewhat lighter and less dense, it does not cease to be plastic, and therefore it has all the advantages of this material.

Plus, polystyrene is resistant to most chemicals.

In this case, a layer of concrete is formed over a layer of expanded polystyrene, which, in turn, rests on a bed of sand and gravel mixture.

The concrete floor screed is also erected on top of evenly laid EPS slabs.

The blind area, insulated with polystyrene foam, will help protect top part foundation from freezing. Plus, a layer of such material will also work as an additional water-repellent layer.

Since the density of extruded polystyrene foam is an order of magnitude higher than that of regular polystyrene, a number of small problems arise with this. For example, this type of material can still be cut with a knife, but firstly, the blade must be extremely thin and strong, since a thick blade can cause the slab to discolor and crack.

And secondly, the creaking and grinding noise that will accompany such an “event” will be an order of magnitude higher than in the case of ordinary polystyrene foam. Therefore, before starting the procedure, it is recommended to lubricate the knife blade with machine oil.

Some people use a grinder equipped with the thinnest metal wheel to cut EPS blocks. Cutting, in this case, is efficient, but the whistle is so loud that it is better to put plugs in your ears. Among other things, this method is the most “unclean”. It will leave a huge amount of garbage behind.

If you decide to use a grinder for cutting polystyrene foam, we recommend that you familiarize yourself with this equipment.

You can easily make a machine or machine for cutting polystyrene foam yourself. To do this, you just need to get some nichrome and a powerful transformer. By connecting the opposite ends of the nichrome wire to the wires coming from the power source, we get a kind of polystyrene foam knife. To make the cut as even as possible, the nichrome wire in the device should be kept taut

The most effective and simplest method is considered to be cutting with hot wire. Take two nails, between which a nichrome wire is stretched. Voltage is applied to the nails through a transformer, the wire becomes hot and the process begins. Using this method, you can cut out the most precise blocks and shapes of a high degree of complexity.

But this method is also the most harmful. As already mentioned, phenol vapors released during the cutting process can cause significant harm to the human body, and therefore, this procedure should be performed outdoors, preferably in a draft or using a special respirator, or even a gas mask.

Few people know, but polystyrene foam makes an excellent formwork for foundations. The material lends itself perfectly to cutting, drilling, etc., and therefore anyone, showing a certain amount of ingenuity and resourcefulness, is able to make a wonderful insulated foundation for their structure

Fire safety measures

When working with extruded polystyrene foam, you must adhere to strict fire safety measures, otherwise extinguishing the fire will be much more difficult than it seems.

That is why, in case work is being done nearby using an open fire, for example, there is a furnace with which bitumen is melted, etc., you should always have a water supply hose, a fire extinguisher, or, at worst, a barrel of water and a bucket at the ready .

It is recommended to do the same when carrying out welding work in close proximity to the EPS. Moreover, it is advised to either shield the material from sparks and scale flying from welding, or pre-moisten nearby polystyrene slabs with water; it is better to do both at the same time. Only in this case will you protect both yourself and your building from fire.

Most fire hazards at construction sites occur precisely because of neglect of safety precautions. If welding work is carried out near work carried out using flammable materials, always expect disaster. To prevent this disaster from happening, you should always keep at least a fire extinguisher on hand.

Conclusions and useful video on the topic

You can learn about the criteria by which extruded polystyrene foam should be selected from the following video:

Considering that almost no one pays attention to the weak sound insulation of insulation, sensitivity to ultraviolet radiation is treated by the fact that the material is always protected by a layer of finishing, and low vapor permeability as a minus is eliminated by the presence of good ventilation, of the total number of shortcomings, only “not environmentally friendly” and the “expensiveness” of the material, but these shortcomings are also easy to refute.

The very concept of “not environmentally friendly” suggests that that the material is extremely durable, because over time, especially with proper use, it does not break down into its components. Isn’t this a criterion for considering “not environmentally friendly”? building material a plus? Well, regarding the high cost of EPS, there is an excellent proverb: “The miser pays twice.” With all the ensuing morals and consequences.

Have you thought about using EPS as insulation and want to clarify a couple of nuances of its use after reading our material? Ask any remaining questions to our experts below this post - we will try to help you.

If you are professionally involved in the installation of XPS and want to give useful tips for beginners or to supplement the above material with valuable comments, write your comments in the block below.

What is polystyrene foam?

Styrofoam is a group of materials belonging to the class of foamed plastic gas-filled masses. “Gas filling” determines the low density of this material, which explains the high thermal insulation and sound insulation qualities of the material.

The starting material for foam plastics can be a wide variety of plastics, which, in collaboration with the technological features of the manufacturing process, determine the final properties of the foam plastic (density, resistance to the environment) and its suitability for various purposes.

The foam that we are used to seeing as packaging for household appliances, is pressless expanded polystyrene.

Historical reference! “Styropor” is the brand name for pressless expanded polystyrene, invented and produced in 1951 by Basf by polymerizing styrene with the addition of pentane (a blowing agent). It is widely known due to its high thermal insulation qualities - it consists of 98% gas.

Expanded polystyrene is a petroleum refining product with very low consumption of raw materials of natural origin.

“Positive” qualities of polystyrene foam!..

A number of its properties speak in favor of this material. Namely…

Properties of polystyrene foam as insulation!

Thermal insulation. This property of foam plastic as insulation is due to the “air-filled” environment of the material, since air is already a good heat insulator, and “enclosed” in porous cells is not capable of convective heat exchange. The result is low thermal conductivity of the material, which determines their high thermal insulation qualities. The closest competitor to foam plastic in the field of thermal insulation is mineral wool, but foam plastic has advantages in ease of processing and installation.

The lower the density of the foam, the higher its thermal insulation qualities. A 10 cm layer of low-density foam is equivalent in thermal insulation properties to a 40 cm pine wall, a 60 cm wall made of aerated concrete, 1 m of expanded clay concrete or 4 m of concrete. This is a strong argument in favor of using polystyrene foam as insulation.

"Loyal" compatibility expanded polystyrene with other building materials, which allows the use of plastering of walls insulated with expanded polystyrene, various types plaster mixtures. Also, foam plastic does not have an aggressive effect on other materials.

Resilience material in biologically active environments, immunity to decay, the action of fungi and bacteria. But!.. Rodents may like polystyrene foam.

Long service life in critically changeable conditions up to 20 years, in normal climatic environments - more than 50 years of maintaining the properties of polystyrene foam as insulation.

Fire resistance polystyrene is ensured by the addition of special ingredients to its raw materials - fire retardants, which prevent active combustion of the material.

Good soundproofing qualities foam in the field of acoustics are determined by the density of the foam, as well as the type of porosity of the material. Let's talk about the sound-absorbing properties and sound-reflecting properties of materials.

The closed porosity of most foams (expanded polystyrene, polyvinyl chloride, extruded polyethylene) contributes to high-quality sound absorption in the range from 1600 to 2000 Hz (for example, fan noise), but at the same time they reflect sound well in a wide range. This determines their use as soundproofing materials.

Open porosity is present in foams such as polyurethane foam. This structure determines the excellent sound absorption of the material throughout the entire sound range, and the virtually complete absence of a reflective effect in the material. This determines the applicability of such material for organizing excellent acoustics in a room, sound speakers, etc.

Foam is capable maintain its shape and size in the temperature range from -60 O C to +95 O C., and, despite its low density, withstand quite large mechanical loads.

Is there any “harmfulness” of polystyrene foam?..

Surrounding ourselves with synthetic materials in modern life, we do not always think about whether this familiar item is dangerous for our health?

Regarding high-quality polystyrene foam, under normal conditions of its use, you can be calm, since it does not emit substances harmful to humans in dangerous concentrations.

Polystyrene foam also has a beneficial effect on the environmental balance in construction, since it is capable of recycling as a thermal insulating filler for concrete mixtures and blocks with internal voids. It can also be used to improve soil structure

Important! Use high-quality material from proven certified manufacturers.

What types of foams are there?

Today, behind the word polystyrene foam there is a large group of polymer materials, similar in production methods and basic properties. How to decide on the choice of the necessary polystyrene foam for insulation or soundproofing of a house? Let's try to figure it out!..

The main types of raw materials for the production of foam plastics:

polystyrene;
polyethylene;
polyvinyl chloride;
polyurethane.

Polystyrene foams

Polystyrene foam is a familiar foam plastic that can be easily seen by opening a box of any household appliances. Looks like a honeycomb when cut.

It consists of small balls interlocked with each other and can be pressed or pressless. The difference in the bond strength of the granules to each other, which determines the mechanical strength of the foam to fracture and tear.

Example of labeling of foam plastics from domestic manufacturers:

PS-4 or PS-1 is a tile foam with a closed-cell structure, made using press technology. Density from 40 kg/m 3 to 600 kg/m 3 ;

PSB-S is a non-pressure foam plastic with self-extinguishing ability.

Is foam plastic harmful as insulation? There is no clear opinion regarding the toxicity of polystyrene foam materials. Polystyrene is, in principle, non-toxic. The danger may be posed by residual styrene, which certain conditions may be released from the foam and negatively affect the well-being of people in contact with it.

Therefore, when choosing such materials, you should give preference to high-quality and certified materials from trusted manufacturers.

The high flammability of these materials also does not speak in favor of their environmental safety. But the introduction of special additives into the raw material made it possible to obtain self-extinguishing foam insulation. But, it is still recommended to use polystyrene foam boards for external insulation.

Extruded polystyrene foam is characterized by higher strength, thermal insulation, and environmental safety. Has a higher price.

“Polyethylene” foam is an elastic, soft to the touch, translucent material. Mainly used for making food packaging.

This type of polystyrene foam is a non-flammable, elastic, low-toxic material.

Polyurethane foams

Foam rubber is a typical example of polyurethane foam. Let's remember... Elastic material, easily allows air to pass through, absorbs water and water vapor and is “afraid” of exposure to sunlight, turning yellow and gradually collapsing upon contact with it. It is used in the manufacture of furniture and insulating and insulating materials for windows and doors. When burned, they release toxic smoke.

Using polystyrene foam as wall insulation is a cost-effective and convenient method of insulation.

Walls, ceilings, roofs, floors, foundations, balconies, loggia can be insulated with expanded polystyrene...

Expanded polystyrene when insulating walls from the outside not only does not damage appearance building, but also “provides” the opportunity to model the facade at your discretion.

Building materials cannot cope with the task of creating a favorable indoor microclimate, so construction cannot be done without additional insulation. Builders often use foam plastic as insulation for the roof, ceiling, attic floor, as well as for the foundation and walls. The material has different technical characteristics for thermal conductivity and thickness, which can be used in accordance with the installation location and needs. Another advantage is the ease of cutting the panels and their installation.

Polystyrene foam, or expanded polystyrene, is a cellular mass of foamed plastic. The characteristic lightness of the material is due to the fact that its main volume consists not of the original polymer, but of air, which, moreover, is a poor conductor of heat.

Marking and density of polystyrene foam

If the letter C (PSB-C) is added to the abbreviation marking according to GOST-15588-86, this indicates that fire retardants have been added to the composition of the foamed polymer and such foam belongs to the flammability group G1 or G2. If this letter is missing, it means there are no fire retardants and it is G3 or G4. The material density indicated in the table means the following:

PSB-S-15 - the number indicates that the density of the panel is not 15 kg/m3, but up to this mark. This is the lowest indicator among all brands, therefore PSB-S-15 is used in places that do not bear mechanical load: insulation of roofs, ceilings, as well as walls and floors under frame cladding. This brand is also used for soundproofing rooms.
PSB-S-25 - density up to 25 kg/m 3, and such panels have a universal application - they are used more often than other materials. In addition to places that do not bear mechanical loads, this insulation is used for building facades with the application of ordinary and decorative plasters.
PSB-S-35 - panel density up to 35 kg/m 3 allows their use in sandwich panels, in reinforced concrete structures(permanent formwork), as well as for arranging waterproofing. This brand is also used for underground work - insulation and waterproofing of basements and foundations.
PSB-S-50 is the most durable polystyrene foam and can be used both for places with low and high mechanical load. Can be used to insulate floors, heated soils and even highways.

Operational and technical characteristics

Thermal conductivity diagram of building materials

The most basic quality of polystyrene foam is low thermal conductivity; this property of polystyrene foam as insulation in comparison with other building materials is shown in the table above. The effect is achieved due to the uniform distribution of air in the volume of the foamed polymer and its thickness. PSB of any density can be used for indoor and outdoor work with any degree of humidity, as well as with temperature changes (the range is from -200ᵒC to +85ᵒC).

In addition to insulation, polystyrene foam is used for sound insulation of certain objects, for example, PSB is laid inside plasterboard partitions or under metal roofing building. Polystyrene foam is a chemically neutral substance and has a high service life. Even when a leak is observed, for example, when the roofing material (corrugated sheeting, slate, etc.) is damaged, the properties of PSB are not lost, since there is no reaction to moisture.

Foam plastic of different thicknesses

Foam panels are resistant to weak acids, alkalis and alcohol, which significantly increases the scope of application. PSB is easy to cut and you can use the most simple tools– a painting knife or a heated nichrome string. Installation is carried out using glue, on umbrella dowels or between profiles.

Technology of using foam plastic for thermal insulation

The ease of cutting foam, ease of installation and low cost contribute to the popularity of the material for private construction. With proper calculations and correct installation foam plastic boards can provide a normal microclimate in residential and non-residential (outbuildings, attics, etc.) premises.

Which side is better to install foam?

Dew point shift depending on the location or absence of thermal insulation

When insulating a building, including an attic, the location of the insulation is of great importance, since this shifts the dew point and the effectiveness of the insulating material. If the stove is installed indoors, the wall still remains cold, therefore, it is necessary to increase the thickness of the polystyrene foam. In addition, the dew point (condensation formation) most often occurs at the point where the foam joins the wall, which leads to the formation of mold.

If the insulation is installed outside, then the dew point shifts to the foam and condensation does not collect due to the lack of moisture inside the foamed polymer. At the same time, the wall warms up from the side of the room and moisture does not get there, therefore, the service life increases. If thermal insulation occurs under roofing material, then it is only internal and condensation cannot form at the junction - the dew point is transferred inside the attic.

Calculation of the thickness of foam insulation

The relationship between the coefficient of thermal conductivity and the required thickness of the material. (*Indicates the addition of a factor of 1.15 for buildings with monolithic belts made of heavy concrete)

According to SNiP 2.09.84.87-2001, the table shows the minimum coefficient for residential and administrative buildings. In addition, for each region there is a certain value of thermal resistance - this is a constant value, which is denoted by the letter R. To carry out an exponential calculation, you can take the average value R = 2.8 (m2 * K / W).

The calculation formula looks like this: R=R1+R2, where R1 is the wall (conditionally brickwork), R2 is the insulation (conditionally polystyrene foam).

The total and individual thickness of materials is calculated using the formula R=p/k, where p is the layer thickness in meters, k is the thermal coefficient of the building material (W/m*k). For an indicative calculation, masonry of two bricks and polystyrene foam of the PSB-S-25 brand will be used.

Insulation of the building with polystyrene foam

The length of an ordinary brick (coefficient 0.76 (W/m*k)) is 0.25 m, which means that the masonry has a thickness of p = 0.25 * 2 + 0.01 = 0.51 m. total thermal conductivity brickwork it turns out Rbrick=p/k=0.51/0.76=0.67 (m2*K/W). Therefore, Rfoam=Rtotal-Rbrick=2.8-0.67=2.13 (m 2 *K/W).

For the total thickness of polystyrene foam, you need to substitute the values into the formula Pfoam plastic = Rfoam plastic * kfoam plastic = 2.13 * 0.035 = 0.07455 m. Please note that the calculation is indicative and neither the thickness of the plaster nor the thickness of the cladding with their thermal coefficient was taken into account. For such walls with finishing (external and internal) and waterproofing, the average thickness of polystyrene foam is usually not 0.07455 m, but 0.5 or 0.6 m.

Material cutting technology

When insulating rooms internally and externally with expanded polystyrene, a painting knife with a sharp blade is used to cut it. This factor affects the clarity of the cut - a dull blade tears the foam and as a result a lot of debris is obtained in the form of small polymer granules. They are very difficult to remove, since, having a static charge, they stick to all objects.

The panels are cut “to fit a ruler”, which is replaced by a building rule or a long level. For cutting, use a wooden plane in the form of a plank board, plywood or OSB, so that the blade does not dull so quickly. In this case, the parameters of the cut fragment must exactly correspond to the parameters of the seat.

Features of installing PSB under plaster

Installation of PSB on umbrella dowels

The most common type of external installation is the installation of foam plastic on umbrella dowels with additional fixation with glue (most often Ceresit CM-11 is used for this). This mount is used for regular or decorative plaster, with preliminary sealing of gaps and gluing of plaster mesh. Taking into account future mechanical loads, the PSB-S-25 grade is needed here.

For such installation, a plane without differences is important, so that the panels laid on it also create a relatively flat plane for the front finishing. In some cases (as a rule, this happens after the walls have been erected), the surface is first plastered and only after that the panels begin to be attached.

Installation of PSB insulation under the frame

Installation of PSB under the lathing for finishing

In the top photo you see the installation of polystyrene foam with virtually no fastenings - here the panels are fixed between the cross beams that support the wooden sheathing. Also, such a sheathing can be attached directly to the wall, but the polystyrene foam is still fixed in an identical way, between the beams (boards). If there are gaps between the panels, then the polyurethane foam.

An identical method is used for interior partitions from plasterboard, where foam is tightly inserted between the profiles. But here PSB serves not so much for insulation as for soundproofing the room.

Installation of foam plastic on the ceiling under metal carcass

Wood itself is an insulator, so installing panels between beams is acceptable, but using this method with metal sheathing is unacceptable. In such cases, PSB is laid under the frame, be it a wall or a ceiling, as in the photo above.

First, the brackets are screwed on to hold the metal profiles, and then the panels are strung onto these consoles, thus covering the entire surface of the wall or ceiling. After this, it is mounted on top of the foam metal lathing– this method automatically creates a ventilation gap between the cladding and the foam, and moisture from evaporation in the room does not accumulate on the surface of the PSB.

Based on the above, the conclusion suggests itself that the properties of foam plastic as insulation are most acceptable not only for the private sector, but also for industrial construction. And if we talk about roof insulation, then this the best option, since there is low thermal conductivity and convenient installation due to the rigidity of the panels.