Thermal insulation properties of foam. Foam insulation: a closer look at the material from all sides

To provide heat in the house, it is necessary to insulate not only the roof, but also the walls.

There is a wide range of materials for wall insulation on the market.

Walls can be insulated both outside and inside.

When the walls are insulated from the outside, the area of ​​\u200b\u200bthe living space is preserved, and insulation technology allows you to provide the building with warm and modern walls.

Before proceeding with the insulation of the walls, it is necessary to determine the method of insulation. Stack or - individual preference. Each method has its advantages and disadvantages. The features of each method of insulation must be studied at the time of the design of the building.

Warming from the inside

Internal wall insulation is characterized by the following features:

• the cost of insulation from the inside is less than for external insulation;
• season and weather do not affect the choice of time for work;
• there is no need to build additional scaffolding for insulation work.

Negative factors for internal insulation are:

• a significant reduction in living space;
• the outer wall is isolated from the heating from the room;
• the probability of the formation of a fungus inside the wall increases, since the dew point is formed precisely in the inner part of the structure;
• when the heating is turned off, the walls cool down quickly due to the low inertia of the insulation;
• the place where the ceiling adjoins the outer wall cannot be equipped with insulation, which leads to the formation of cold bridges.

The method of wall insulation from the outside is more popular despite the fact that the cost of labor and materials for performing work is much higher than the method of internal insulation.

Dew point

Warming outside

The advantage of wall insulation from the outside is:

• in winter and in cold weather, heat is stored in the wall for a long time;
• the design area of ​​the premises is preserved;
• external thermal insulation protects the internal walls from moisture.

In addition, the outer walls are additionally protected from the effects of atmospheric phenomena, which significantly increases the service life of the structure.

The main disadvantages of external thermal insulation of a structure are:

• limiting the performance of work in accordance with weather conditions;
• increase in the cost of materials used.

Which side of the wall should be insulated with polystyrene foam

It is advisable to insulate walls with expanded polystyrene from the outside, since the material does not allow air to pass through, which can lead to condensation inside the wall during internal insulation, and inside the room, the material can emit a specific smell.

Advantages and disadvantages of expanded polystyrene

Expanded polystyrene material is porous air-containing raw materials, is used in most cases as a heat-insulating material.

In industry, the material can also be used as an electrical insulating and packaging material.

The material has gained wide application due to its quality indicators:

• low level of water absorption;
• low thermal conductivity;
• ease;
• biological stability;
• durability;
• compressive strength;
• not affected by temperatures;
• ease of installation;
• low material cost.

Comparison of heaters

Despite the impressive list of positive indicators, expanded polystyrene has disadvantages that must be considered during installation:

• low sound insulation;
• instability to solvents and many chemicals;
• afraid of fire. When burning, it releases harmful toxic substances;
• poor resistance to ultraviolet;
• easily susceptible to rodents and insects, which, by making holes in the material, provoke its destruction;
• low vapor permeability;
• fragility.

However, the production technology of these materials is different.: polystyrene foam is produced by extrusion, when the granules melt when combined into a single structure, polystyrene foam - by gluing the granules with dry steam.

Specifications

Types of expanded polystyrene

Expanded polystyrene is classified according to the method of production of the material and the inclusion of various additives in it:

• extruded polystyrene foam. Produced by pressing;
• non-pressed polystyrene foam. Produced by removing moisture in a drying process and then foamed at high temperatures;
• Not much different from non-pressing, an extruder is additionally used in production. The best and optimal option for thermal insulation of walls.

There are other types of expanded polystyrene (extrusive, autoclaved), but they are not used as heaters, because they have different characteristics.

In addition to the types of expanded polystyrene, there are also various types of insulation, such as:

Pie wall when using insulation - expanded polystyrene outside

A wall pie is called layers of materials that are stacked in a certain order, each of which performs its own functions to ensure a normal microclimate in the room.

When thermal insulation of brick walls with polystyrene, laid outside, pie wall looks like this:

• internal plaster;
• outer wall;
• adhesive solution for gluing polystyrene foam;
• insulation (polystyrene foam);
• adhesive solution for gluing the next layer;
• fiberglass mesh;
• adhesive composition;
• primer;
• finishing plaster.

NOTE!

When arranging a wall using expanded polystyrene, it is necessary to lay the layers in a strict sequence.

Internal and finishing plaster can be replaced with other finishing materials, which are provided by design solutions.

Wall cake "wet"

Issues of vapor barrier and waterproofing

An important requirement in the construction and home improvement is the correct implementation of all work to ensure ventilation and waterproofing, since it is the incorrect installation of these components that significantly reduces the characteristics of the structure.

When insulating walls with polystyrene, waterproofing is not needed.. It should be noted that with a high passage of groundwater under the building, it is imperative to waterproof the basement and foundation.

Since expanded polystyrene does not allow air and water to pass through, it is not necessary to lay a vapor barrier layer when insulating walls from the outside.

Insulation wall pie for siding

Sealing gaps and preparing the crate

Installation of polystyrene foam on the crate is the most time-consuming process among the insulation options. Most often, the crate is done in the case of finishing with siding.

Crack sealing

If it is planned to carry out work on the installation of siding on the wall of a house made of beams, then you must first seal the seams with high quality, clean the surface of dust and debris and seal the gaps with sealants, mounting foam or a mixture of sawdust and PVA.

If the wall is concrete, brick or foam blocks, then cracks in such houses are cleaned of sand, treated with a primer, then sealed as follows:

• if a small gap. The prepared mixture of cement and sand with the addition of PVA closes the gap with a spatula;
• if the gap is medium in size. At a distance of 20 cm, make holes for dowels. Using screws with washers, pull the metal mesh over the gap and seal it with plaster pressed into the mesh. Next, apply the final layer;
• P ri big crack. Seal the gap with mounting foam, cut off irregularities and seal with plaster in two layers.

Large cracks can be repaired with anchors:

• knock down the plaster, close up the splits with mounting foam;
• install a channel in the opening and fix a reinforcing mesh on it;
• you can use staples from reinforcing mesh;
• apply plaster;
• putty.

Crack sealing

When the wall is prepared for laying insulation, you can mount the crate.

Crate preparation

The crate for siding can be made from a metal profile and from a wooden bar. In humid climates, it is advisable to install metal rails.

Before proceeding with the installation of the crate, it is necessary to determine the location of the siding:

• with horizontal siding. The beam or metal profile is installed perpendicularly;
• with vertical siding. Frame boards or metal profiles are installed in a horizontal position.

The step of the crate is determined by the width of the expanded polystyrene sheet: in width it should fit tightly between the laths of the crate and not form a gap.

The order of work is determined by the steps:

• treat the wall with special mastic;
• frame boards are fixed around the entire perimeter of the walls with galvanized screws and plastic dowels;
• if holes are formed between the beam and the wall, these gaps are sealed with pieces of polystyrene foam by gluing them to the wall.

CAREFULLY!

If the crate is made of wood, the boards must first be treated with antiseptic agents.

The implementation of the crate does not require special skills, but it should be noted that the choice of materials should be made based on climate conditions.

Sheathing for siding

Wooden crate

The technology of wall insulation with polystyrene from the outside

Before proceeding with the insulation of the wall with polystyrene foam, it is necessary to dismantle the drains, decorative elements, clean and prime the wall. Next, make thermal insulation of ebbs and window slopes.

Now let's talk about the thickness of polystyrene foam.

NOTE!

When insulating walls with extruded polystyrene, sheets are used, the thickness of which is from 80 to 100 mm and more.

You can also use thinner sheets. 30-40 mm thick if laid in two layers.

Let's start installing the insulation on the walls with our own hands:

• a profile is installed at the bottom of the wall to hold the expanded polystyrene;
• an adhesive mixture is applied to the wall over the entire area pointwise and onto the insulation sheet (abundantly on the center and edges of the sheet);
• tightly attach the sheet for gluing to the wall;
• fasten the panel with dowels in such a way that the dowel enters the wall by at least 50 mm. The location of the dowels is made in the center of the panel and at the joints. It is recommended to use plastic nails;
• if gaps are formed (up to 2 cm), then they are sealed with mounting foam if the gaps are larger, then they are first sealed with pieces of insulation, and then foamed. Excess foam is cut off;
• the heads of plastic nails are cleaned and puttied.

After installing the insulation, a reinforcing mesh is applied to the facade. Grid strips should be cut into corners and slopes and glued with an adhesive with a spatula. An adhesive composition is applied to the grid along the wall so that it penetrates through the grid onto the polystyrene foam by 0.1 cm. If an overlap forms, separate strips of the grid are superimposed on it and glued additionally.

Sectional device

Fixing plates with dowels

Applying mounting adhesive

After complete drying of the surface, it is leveled with fine-grained sandpaper.

Useful video

Detailed video instruction on wall insulation with extruded polystyrene foam:

In contact with

Energy prices are constantly rising. And every family does not want to pay a lot of money for heating the house. And here the natural question arises - "What to do?". Get warm! In such cases, heating costs will be significantly lower. And not infrequently, among the variety of heaters, people choose foam.

Is it worth it to insulate the walls with foam?

Everyone decides for himself. And if you have not yet decided on this, it is worth analyzing all the subtleties and nuances of using polystyrene foam as a heater. After all, there will always be both positive and negative aspects of this.

Polyfoam - cheaper and easier

Many builders choose him for a reason, because he:

• easy to install (even beginners can handle it);
• is not expensive;
• has a low weight;
• installation is very fast.

Important! Foremen consider mineral wool to be a similar material, but it is much more expensive than it.

But many highlight its main disadvantage - increased flammability. However, this issue is also partially resolved - by purchasing special grades of foam plastic marked "C" - self-extinguishing.

Increasingly, this material is used for insulation of residential premises. And the concept of environmental friendliness plays an important role here. When heated, it (more than +40 C) begins to release a harmful substance - styrene. That is why it is not recommended to use it for warming a metal roof, and other similar heating elements.

Most builders advise not to use it for interior work, but only for exterior. Moreover, this method of insulation has other advantages:

• the previous geometry and usable area will be preserved;
• the freezing point will move to the outside of the house;
• fungus and mold will not form between the wall and the insulation;
• destructive environmental factors will not affect the walls of the house.

Important! When insulating with foam from the outside, harmful substances and their evaporation are minimized, in contrast to its use in internal work.

Of course, this material is good, but before deciding on its use in your home, you need to understand that it can not be used everywhere.

So, it will cease to be good if:

• rodents live in the house;
• high humidity;
• poor ventilation.

If the above does not apply to your premises - you can safely use it. Therefore, it can be found more often in apartments, and not in private homes.

Styrofoam - insulation not for private houses

As an example, let's take a situation where polystyrene foam was used to insulate a garage building, which was adjacent to a private house. The joints of the plates were covered with mounting foam. With its thermal insulation function, this material did an excellent job. The room felt noticeably warmer.

But after a short time, mice from the house made moves in it, in some places - through and through. And the insulation work was ruined.

Styrofoam - high-quality insulation for walls

Apartment owners have long been convinced that if the installation work on this insulation is done efficiently, then in winter the wall will please with dryness, and in summer - with coolness. The last factor does not mean that this material works as a coolant.

It just does not keep the temperature in the apartment in the state in which it was originally. And if it has an individual heating plan, then it saves heating costs.

Even if a decision is made to insulate the walls, special tools are not always at hand. And this moment also plays an important role when the material with which these works will be produced is selected.

As practice has shown, in order to install the foam on the outer wall, you just need to adhere to a certain stage of work. Although there is an opinion about the simplicity of such work, irresponsibility can negate all the work.

1. Insulation sheets are laid in a checkerboard pattern, so that the joint from one row falls in the middle of the sheet of another row. All elements are carefully coated with glue.

Important! Choose an antifungal-labeled glue or add a special mixture to it.

2. If there are irregularities on the butt joints, they must be rubbed to perfect condition.

Important! Even the smallest gap at the junction must be puttied.

3. We reinforce our structure to give it the necessary rigidity. To do this, we use a facade mesh, which we glue with a special mixture.

4. We strengthen with the help of a mixture for reinforcement, which we will apply with an additional layer after the reinforcing layer dries.

5. We prime our walls.

6. We complete the work by applying a decorating layer: plaster, decorative plates, facing bricks, etc.

I work for a construction team. We mainly insulate apartments with this material, along the outer perimeter. Not the best option for giving, especially if you keep a bird. They peck clean.

Grade:

Igor, 47 years old, Peter.

About five years ago I insulated the roof with this material. Mounted with my brother in a day. So far everything is great. Everyone is alive and well, no harm was found.

Grade:

Nikolai, 34 years old, Voronezh.

They insulated the bathhouse and the summer kitchen. Ease and simplicity of installation - a class. Well reinforced, top quality plaster. It's been going on for two years now. And yes, chickens walk in the yard - they don’t peck.

Grade:

Alexander, 28 years old, Kyiv.

The corner room in my apartment has always been problematic - cold, there is a fungus on the wall. In the summer, they insulated the outside with polystyrene five. Very satisfied. Now there - dry, warm and no fungus. This is now my daughter's room.

First, let's clarify the terminology. The name "foam plastic" can be attributed to the group of foamed cellular plastics or gas-filled polymers, which include, for example, polyurethane foam, which we wrote about in the article "", as well as foam plastic, foamed polyethylene foam, synthetic rubber and others. Here we will talk exclusively about polystyrene foam.

Styrofoam - expanded polystyrene, or PPS, has many positive characteristics, such as an affordable price with a fairly low thermal conductivity, ease of processing and installation, low weight of the material, etc. But this material is endowed with a number of negative properties: the ability to release toxic substances into the air when ignited, the ability to gradually decompose under the influence of oxygen in the air, temperature changes and, in this connection, low durability, etc. We will touch on all this in more detail below and help the reader to make an objective assessment of the properties of PPS and evaluate the possibilities of using foam for insulation.

Foam production and its varieties

The industrial production of polystyrene, or expanded polystyrene, began in the middle of the last century. This material has been used in many areas of human activity - as a convenient packaging for various household goods and industrial equipment, food, thermal insulation of refrigeration units, etc. In the second half of the last century, foam plastic was widely used as thermal insulation in building envelopes.

Expanded polystyrene can be divided into two main types:

• material grade PSB (non-pressing expanded polystyrene) according to the terminology adopted in the Russian Federation, or EPS - according to international terminology, obtained by the non-pressing method. If the marking contains the letter “C” - PSB-S, then this means that fire retardants have been added to the material during production, which impede combustion;
• extruded polystyrene foam brand EPPS (extruded polystyrene foam) according to domestic terminology, or XPS - according to international terminology, which differs in the method of manufacture and properties.

PSB foam production technology (pressless expanded polystyrene)

The non-pressing method for the production of expanded polystyrene was developed by technologists of the chemical company BASF in Germany in the 50s of the XX century and has been used almost unchanged in the production of foam products since then. The production line for the production of foam boards for construction includes a steam generator that produces steam at a temperature of up to 170 ° C, a pre-expander, a aging hopper, a block mold, a device for cutting foam blocks.

The feedstock for the production of foam products is suspension polystyrene in the form of small granules 0.5-1.5 mm in size. The choice of raw materials, their quality and the size of the granules are important for the production of the final product. Foam boards of higher density are produced from polystyrene with small granules, in addition, fire retardant additives can be added to the feedstock, which increase the fire resistance of the insulation.

The production process of foam boards consists of the following steps in sequence:

• primary foaming of a mass of polystyrene granules in a unit called a pre-expander under the influence of water vapor at a temperature of more than 100 °C. At the same time, the isopentane hydrocarbon contained in the polystyrene granules boils, which causes an increase in the volume of the granules tenfold. Approximately 1 m³ of foamed granules is obtained from 15 kg of feedstock;
• from the pre-expander, the foamed granules enter the bunker, where, under the influence of hot air coming from below and mixing the entire mass, they are freed from excess moisture;
• then, using a pneumatic transport system, the dried granules are fed into the aging bunker, in which the granules are stabilized after primary foaming. In the same place, when the granules cool, a vacuum is formed inside them, while most of the blowing agent - isopentane - is replaced by air;
• The main operation for the manufacture of foam is to supply foamed and aged granules into a block mold, in which, under the influence of water vapor, the mass is sintered into blocks of a certain size. During the sintering process, spherical granules are deformed under pressure, forming closed cells in the form of polyhedrons;
• after the blocks are formed, they go to aging, during which excess moisture is removed from the blocks;
• then the aged blocks are fed to the cutting table, where they are cut into slabs of a certain thickness and size using a system of strings. The cuttings are returned through the crusher to the receiving hopper, where they are mixed with new raw materials, thus, the production of foam plastic becomes waste-free.

Foam boards must comply GOST 15588-86 (ed. 1987) "Polystyrene foam boards", which establishes requirements for performance, dimensions, conditions of transportation and storage.

Characteristics of PSB foam (pressless expanded polystyrene)

We will show the properties of the foam for the most common grades of PSB in the table:

Production technology of extruded polystyrene foam

The technology for the production of extruded polystyrene foam (EPS) differs from the method of manufacturing conventional EPS by the presence of a special unit - an extruder, in which the initial mass of polystyrene granules is melted to a viscous-fluid state under pressure. Carbon dioxide is used as a blowing agent. Further, this mass is pressed through slit-like dies, where it is compacted and takes the desired shape, as a result, a long insulation tape is formed, which is then cut into plates of the desired length.

Advanced technology allows you to get a heater with better characteristics. EPPS has a higher density, strength, lower thermal conductivity and other improved qualities compared to PSB due to a more integral microstructure formed by smaller air-filled cells with impermeable walls of 90-140 microns in size and more tightly bonded to each other.

The differences between the characteristics of PSB and EPPS can be seen in the following table:

The principle of operation of PPS (expanded polystyrene) as a heat insulator, positive and negative properties

The use of foam as a heater became possible due to its structure. If we examine a section of a foam plate under a microscope, we can see that this material consists of porous granules glued together. The air filling the granules in the final product makes up most of the volume - up to 98%, which gives the foam lightness and high heat-shielding properties.

Pros of Styrofoam

Expanded polystyrene used in construction has the following positive properties:

• sufficiently low thermal conductivity, at the level of mineral wool insulation, to provide sufficient thermal protection of buildings with optimal material consumption;
• water absorption, practically equal to zero;
• relatively low cost compared to most effective heaters;
• ease of installation - PPS boards are cut with a hand tool to the desired size;
• strength, graded or grouped by brand, allowing the use of insulation in enclosing structures subject to different loads.

Cons of foam

There are also a number of disadvantages:

• expanded polystyrene PSB belongs to class G3 - normally combustible materials, according to the classification of a regulatory document Federal Law No. 123 "Technical Regulations on Fire Safety Requirements". Tests by manufacturers regarding the behavior of the material in case of fire indicate that the PSB-S insulation with flame retardant additives, when exposed to an open flame, self-extinguishes within a few seconds. However, numerous cases are known when fires occurred with human casualties due to poisoning with toxic substances released not during combustion, but even during the melting of polystyrene foam under the influence of high temperatures;
• the vapor permeability of PSB and EPPS foam is zero - this property can be classified as negative, which manifests itself in the case when the outer wall of the house is insulated with foam;
• expanded polystyrene decomposes when exposed to atmospheric oxygen and solar ultraviolet radiation, so the insulation layer must be protected with the help of various coatings: sheathing with plasterboard sheets, plastering, cladding with facade materials. On the facades, the insulation layer can be hidden under siding, porcelain tiles, facade panels made of composite materials, etc.;
• low resistance to organic solvents - gasoline and diesel fuel, alcohols, concentrated acids. If you pour any of the organic solvents onto the foam, it will melt and turn into a liquid mass, which, after the solvent evaporates, will harden and turn into a solid plastic spot;
• the high hydrophobicity of the material does not allow microorganisms to develop inside it, but mold fungi harmful to humans can start on the surface of the insulation when contaminated. In addition, rodents can easily gnaw passages in the insulation layer and build nests there;
• low durability compared to the solidity of buildings. Many manufacturers claim the durability of foam plastic in 15-30 years, however, before insulating the wall with foam plastic with your own hands, you should think about the fact that in 20 years you may have to make repairs with a complete replacement of the insulation.

Fire hazard of foam

The most famous case with many victims who were poisoned by combustion products is a fire at the Lame Horse nightclub in Perm, where a suspended foam ceiling caught fire. Fire safety regulations expressly prohibit the use of materials with such a combustibility group as foam plastic on escape routes and in places where mass congestion of people is possible - in residential buildings and public buildings, entertainment venues, restaurants, cafes, etc. In the case of In a nightclub fire, Styrofoam was used as soundproofing, which is wrong, since this material is not used for soundproofing. What materials can be used for soundproofing can be found in the article "".

The use of foam plastic for insulating low-rise private houses is not regulated by fire safety standards, but in the case when it is necessary to insulate the walls from the inside, it should be provided that the insulation layer is covered with materials that have a high degree of fire resistance, for example, plastering over a mesh or sheathing with plasterboard sheets. These materials for a certain time can protect the insulation from flames in case of fire and prevent the release of toxic substances into the air from the insulation layer.

Vapor resistance foam

We have already written about the principle of designing external multilayer walls in the article "", according to which the vapor permeability of materials in a building envelope consisting of several layers should increase from the inside out. This allows water vapor, which accumulates in the air inside due to free gas exchange, to exit through the walls to the outside, maintaining a normal microclimate in the premises. If the wall contains a vapor barrier layer, as is the case with polystyrene foam, then water vapor will introduce itself in different ways - depending on the location of the layer.

When the house is insulated with foam plastic from the inside, water vapor will overmoisten the air in the room, creating uncomfortable conditions, and if the dew point is close to the inner surface, it will tend to condense at the junctions of the inner and outer walls, at the corners and slopes of window openings. If the insulation layer is located outside the wall or inside it, as in the case of three-layer masonry, then water vapor will penetrate the wall and saturate it to the boundary of the insulation. Moisture saturation of any building structure is undesirable, since with constant moisture it causes many negative consequences - increased corrosion, reduced performance and destruction of the material.

All of the above processes do not occur at once, but over a long period of time, during the change of seasons, and the nature of these processes is highly dependent on the climate in the region where a particular building is built. If the autumn-winter period is short, as in the southern regions of Russia, then the dampening of the wall will be insignificant. And during the long spring-summer period, moisture from the wall will evaporate into the room without causing much damage. If the house is built in the northern regions, then the consequences of moisture saturation of the wall can be more dangerous for the structure.

In any case, it is necessary to correctly calculate the thickness of the entire structure of the outer walls and the thickness of the thermal insulation, so that the dew point under the most unfavorable conditions is within the insulation, then all the unpleasant consequences of moisture structures can be avoided.

If the house is insulated with foam plastic with your own hands outside or as part of a three-layer structure, then the best way to protect the walls from saturation with water vapor is to cover the walls from the inside with a vapor barrier film, followed by plasterboard finishing. In this case, vapors from the air will not penetrate the walls, but then the humidity of the indoor air will increase. To solve this problem, it is necessary to equip the house with a forced ventilation system with an air dehumidification function.

The use of PSB foam (pressless expanded polystyrene) in construction

Polyfoam PSB, depending on the density, is used in construction for the following purposes:

• PSB-S-15 can only be used for thermal insulation of temporary structures - change houses and containers, as it has low density and strength;
• PSB-S-25 can be used for thermal insulation of structures that are not subject to high loads - water pipes (insulation of heating networks is not allowed, since the material decomposes rapidly when exposed to high temperatures), loggias and balconies, walls of houses with a wooden supporting frame, roof trusses and mansards, ceilings made of wooden beams, floors of residential and office buildings, three-layer walls made of stone materials, exterior walls of buildings using the “wet facade” method coated with a plaster layer;
• PSB-S-35 is used in the manufacture of sandwich panels, including reinforced concrete three-layer panels, insulation of floors and exploited ceilings with increased loads, flat roofs. Insulation of external walls with foam plastic of this brand is not economically feasible, since it has a higher cost than PSB-S-25.

The use of EPS (extruded polystyrene foam) in construction

As we can see, EPPS has significantly better properties in all respects, which makes it possible to use this material in the construction of structures in which the use of conventional PSB foam is unacceptable:

• in underground structures when insulating basement walls, blind areas, shallow strip foundations, which prevents deformation of heaving soils during seasonal freezing;
• in the construction of the UShP foundation - an insulated Swedish slab, where EPPS slabs are laid on a soil base under a monolithic reinforced concrete slab, along its side walls and under the blind area, serving as an insulating cushion that protects the soil from freezing and deformation, and also protects against heat loss through foundation structures. The strength of XPS allows it to withstand high compressive loads;
• as underlying layers for the roadway, protecting the base from frost heaving;
• in enclosing structures - walls, ceilings, roofs and floors. In this case, it is necessary to calculate the economic feasibility of using XPS, since this material is more expensive than conventional foam plastic of PSB grades.

Styrofoam insulation technology using the “wet facade” method

Thermal insulation of the facade with foam plastic, the technology of which is developed in detail in the technical document "Typical flow chart for the installation of insulation of building facades with subsequent finishing using the "wet facade" technology, most fully takes into account the positive and negative properties of this material and consists in the phased implementation of the following work:

• preparation of the surface of the outer wall - cleaning from pollution, sagging of mortar and other irregularities;
• primer coating with a roller or brush twice. Coating with a primer improves the adhesion of the insulation layer to the wall surface;
• fixing the basement metal profile with expansion dowels at the zero level of the building, on which the first row of foam plates will rest;

• gluing foam boards to the wall with a cement-based adhesive. The dry mixture is diluted with water in a proportion of 5.5 liters per 25 kg of the mixture and thoroughly mixed with a drill with a nozzle. The adhesive mixture should be used up within 4 hours. The adhesive mass is applied to the insulation plate along the perimeter with a strip of 40-50 mm wide and several cakes along the central line with a thickness of 30-40 mm. The slab must be covered with a layer of glue not less than 50% of the area;
• after coating with an adhesive solution, the slab is put in place and pressed against the wall with a wooden trowel, controlling the horizontal and vertical position with the help of a level. The insulation is glued to the wall in horizontal rows with the displacement of each subsequent row in a checkerboard pattern. The width of the joints between the plates should not exceed 2 mm. If this value is exceeded, narrow strips of insulation are inserted into the seams without the use of an adhesive solution to prevent the occurrence of cold bridges;

• two days after gluing the insulation boards, they are additionally attached to the wall by means of dish-shaped dowels;

• after three days, the insulation is covered with a reinforced layer of adhesive solution. The solution is first applied in one layer, into which a polymer plaster mesh is embedded, then the mesh is covered with a second layer of the solution. The coating with a reinforced layer is made in strips about 1 m wide, the total thickness of the layer should not be more than 3 mm;

• after applying the reinforced layer and setting it after 2-3 days, using a felt roller or brush, a preliminary application of a plaster lining mass is performed, which plays the role of a primer for better adhesion of the subsequent plaster to the base;
• then, with floats, the facade is plastered with mineral or acrylic plaster;
• the final stage is painting the facades after the plaster has completely dried with facade paints.

Full scheme of the "wet facade"

All work on the construction of the reinforced layer, plastering and painting should be carried out during the warm period in the temperature range of 5-25 ° C in the absence of rain and in calm weather.

Insulation of walls from different materials using foam

The technology for insulating walls with foam plastic constructed from other materials and in other ways, for example, three-layer brick walls or using the construction of a ventilated facade, practically does not differ from the technology for insulating with stone wool, which we described in the article "" in the sections "Arrangement of ventilated facades" and " Insulation of multilayer walls.

Warming the walls of wooden frame houses is not very difficult and is easily done by hand. Foam boards are inserted into the space between the racks of the frame, covered from the inside with a vapor barrier film, and from the outside with a moisture-windproof film, then sheathed from the inside with OSB boards, and from the outside with facade cladding elements.

Wall insulation of log cabins, wooden houses made of profiled or glued beams with expanded polystyrene is undesirable due to its vapor impermeability. Wood is a natural, "breathable" material, which, thanks to its high water vapor permeability, provides the most favorable indoor climate.

If you create an impenetrable barrier due to insulation, then it will not be comfortable inside due to high humidity. In addition, wood itself has high thermal insulation properties, so if you choose the right log diameter or timber thickness in accordance with local climatic conditions, then no additional insulation is required.

Insulation of walls made of aerated concrete, expanded clay concrete and other blocks of lightweight and cellular concrete is carried out using the “wet facade” technology described above, either as part of three-layer walls with brick cladding, or using a ventilated facade technology. In this case, one must remember about vapor permeability. Since lightweight concrete blocks have increased vapor permeability due to their high porosity, they should be protected from moisture saturation from the premises with the help of a vapor barrier film, which must be wrapped around the walls from the inside and then hidden under the finish.

Opinion of portal site experts

According to portal experts, when using expanded polystyrene as a heater, all its positive and negative properties must be taken into account. In particular, its fire hazard and vapor impermeability should be taken into account. To minimize the negative properties of the material, it is necessary:

• purchase material grades designed for use only in certain enclosing structures. At the same time, customers and contractors should be aware that the density grades declared by manufacturers may often not correspond to reality. For example, PSB-25 foam plastic with a nominal density of 25 kg/m³ can actually have a density of 15.1 kg/m³ at the level of packaging polystyrene foam, which is not suitable for use in critical building structures. Therefore, you should purchase material from trusted manufacturers such as BASF, Styrochem, Polimeri Europa, Nova Chemicals, TechnoNIKOL;
• strictly observe the technology of the device for insulating building envelopes and provide for all necessary measures to protect the insulating layer from fire, solar radiation, and the effects of chemical and biological factors;
• provide for a vapor barrier in combination with insulation to protect load-bearing structures from moisture.

If all the required standards are met, the foam plastic or expanded polystyrene insulation can last the entire declared service life without losing heat-shielding qualities.

In an effort to keep costs down, many of us are looking to Styrofoam as wall insulation - both outside and inside. Despite the fact that this material has a number of disadvantages, it can be successfully used for this purpose. Based on my experience in facade work, I will tell you what to pay attention to first of all and how to properly lay the foam as a heater.

Pros and cons of the material

Advantages

Styrofoam is a porous polymer material that is also used to insulate buildings. The use of foam as thermal insulation allows us to talk about the following properties:

1. Low thermal conductivity. Finishing the walls with a sufficiently thick (50-150 mm) layer of material allows you to minimize heat loss.

1. Good soundproofing. Due to the porous structure, the foam layer not only insulates the wall well, but also protects the room from loud sounds from outside.

1. Small mass. Using polystyrene as a heater, we reduce the load on the supporting structures and the foundation. So for light buildings this material is a great solution!

1. Ease of processing. Thermal insulation boards are easy to cut, fit and install. It does not require any special skills or specialized equipment.
2. Low price. The cost per square meter of foam insulation 50 mm thick is about 120 rubles, 100 mm thick - about 250 rubles.

disadvantages

Now - about the shortcomings of the material:

1. Low strength. Even pressed foam plastic is characterized by low density, therefore it does not resist mechanical stress well. A thin layer of plaster finish does not solve the problem, so the insulated facade can suffer from both hail and falling tree branches.

1. High combustibility. Even a special foam for wall insulation - the so-called architectural - refers to combustible materials. When exposed to high temperatures, it melts, releasing toxic fumes. Therefore, it is important to protect the thermal insulation from contact with fire.

Cheaper packaging foams have an even higher flammability index. So saving by using them for insulation is not worth it!

1. Low vapor permeability. Polymeric heat-insulating materials (polystyrene, expanded polystyrene and their analogues) do not allow moisture to pass through. Because of this, the natural ventilation of the wall fencing is disrupted, and condensate accumulates under the insulation layer in the thickness of the wall. This leads to the appearance of fungus and other unpleasant consequences.

These shortcomings are not fatal. And if you take them into account, then you can use polystyrene foam as facade thermal insulation.

What is needed for insulation?

Styrofoam or alternatives?

When choosing materials for thermal insulation, you will have to decide what is better for insulation - polystyrene foam, polystyrene foam, mineral wool or something else?

In this case, the comparison should be carried out immediately on a number of parameters:

1. Thermal conductivity. When choosing what will be used for finishing - polystyrene or mineral wool - first of all, let's pay attention to thermal conductivity. Here, the materials are almost parity: stone wool has a thermal conductivity coefficient of 0.045 W / (m ° C), polystyrene - 0.04.

If we have a choice of foam or mineral wool, then there is an advantage in favor of polystyrene plates. They have a thermal conductivity index of 0.035 W / (m ° C), so there is a slight gain in heat.

1. Strength. Here, both polystyrene and dense mineral wool products win over foam boards.
2. Flammability. From the point of view of safety, the facade boards based on mineral fiber have an advantage. Unlike polymeric heaters, they practically do not burn and do not support combustion.

1. Ventilation. For vapor barrier, mineral wool is also preferable. If vapor-permeable materials are used for exterior decoration, then the natural ventilation of the facade will be preserved.
2. financial considerations. Cost may also be a priority. When choosing which is more economical - polystyrene or mineral wool - it is important to compare materials of the same purpose. In principle, you can find rolled mineral wool cheaper than polystyrene foam. But only dense slabs are suitable for facades, so foam plastic will be more profitable here.

As you can see, it is difficult to make an unambiguous choice. You will have to not only decide what is warmer, but also look at other indicators! In general, foam plastic is an economical option for insulation: you can find it better, but it’s unlikely that it’s cheaper.

Materials for the thermal insulation layer

Wall insulation with foam plastic involves the formation of a multi-layer finish. Its basis is the heat-insulating material itself, which must meet certain requirements:

1. Density. For outdoor work, we choose polystyrene PSB-S 25/35 (density 25 or 35 kg / m 3). Grades with a lower density (PSB-S 10 and 15) are used for wall insulation under dense sheathing and for laying inside.
2. Thickness. The optimal dimensions of the insulation layer are from 75 to 150 mm. To reduce heat loss, it is better to lay two heat-insulating layers with offset seams - so there will be no blowing at the joints of the plates.

In addition to foam for wall insulation, you will need:

Illustration	Material
	Adhesive composition on a cement, bitumen or polymer basis.
	Mounting low-modulus foam.
	Stucco mesh.
	Dowel dowels.
	Finishing materials for the facade: putty; decorative plaster; facade paint.

You may also need: plaster and repair mixtures, primers, antiseptics, metal profiles.

Tools and fixtures

Warming the facade of a building with your own hands involves the use of a certain set of tools. The optimal list includes:

1. Perforator.
2. Drills for brick or concrete.
3. Drill with mixer nozzle.
4. Spatulas for applying glue, putty and plaster.
5. Styrofoam knife or saw.
6. Plaster trowels.
7. Brushes for paint and primer.
8. Gun for polyurethane foam.
9. Level, tape measure and plumb line.

In addition, for the installation of insulation, you will definitely need scaffolding or full-fledged plaster scaffolding.

But the external insulation of the walls of an apartment located above the second floor is best left to professionals. These are already high-altitude works, and it is not so easy to ensure safety on them: you need not only the appropriate equipment, but also skills.

Facade thermal insulation technology

Outside or inside?

When starting to insulate a room using foam, it is important to decide in advance whether we will install the insulation from the inside or outside. I (like the vast majority of decorators) strongly recommend the second option.

Benefits of outdoor insulation

1. Saving free space. The useful volume of the premises does not decrease, which is especially important in the case of loggias, balconies and small rooms.
2. Efficient heat retention. The wall warms up from the inside, and does not have time to cool down during the night, because it does not come into contact with the external environment.
3. Dew point offset. The conditional temperature line, along which the condensation of water vapor occurs, is displayed outside the wall enclosure. Thanks to this, condensation does not form in the thickness of the wall, and this prevents freezing.

The last aspect is very important, especially for brick walls. When condensation forms, the masonry begins to break down more intensively, so we not only insulate the house, but also save it!

How to properly prepare a wall?

The process of preparing a wall for insulation with foam boards is quite simple. We need to perform a rough leveling and ensure that the base adheres to the adhesive.

Illustration	Preparation stage
	Elimination of defects. We inspect the wall, revealing cracks, crevices and other defects. We knock down large irregularities with a perforator. We also clean cracks and crevices by removing weakly adhering fragments of material.
	Damage repair. After jointing and cleaning, all defects are filled with cement mortar. The surface of the solution is leveled with a spatula.
	Primer. Apply a penetrating primer to the cleaned and leveled surface. We carry out the treatment in two steps, pausing between sets at 6-12 hours.

Checking the readiness of the wall for insulation is quite simple. To do this, we glue a small fragment of polystyrene on the surface and after a while we try to tear it off. If the foam itself is torn, and the adhesive layer does not peel off from the wall - we did everything perfectly!

How to insulate the facade with foam boards?

The instruction assumes double fixation of the foam. What does it mean? First, we glue the foam, and then we fix it with dowels, followed by plaster.

Illustration	Mounting operation
	Setting the start profile. At the level of the future plinth or at ground level (if the plinth is not provided), we mount the starting profile, the width of which corresponds to the width of the insulation used. We set the profile strictly according to the level, fixing it with anchors to the supporting structure.
	Glue mixing. Pour the adhesive composition for polystyrene / polystyrene into water and mix with a mixer until a homogeneous mass is formed. Then we keep the glue solution for at least 5 minutes and mix again, completely eliminating lumps. If the glue has thickened, we “reanimate” it only by intensive mixing. Under no circumstances should water be added!
	Slab cutting. We cut the foam boards to size using a sharp knife or a saw with fine teeth. When trimming, we try to cut the slabs so that the number of joints is minimal.
	Application of glue (for uneven walls). Apply a bead of glue approximately 5 cm wide around the perimeter of the foam panel. Small slides are symmetrically arranged in a free area. In total, adhesive areas should occupy about 30-40% of the entire plate.
	Application of glue (for smooth walls). The glue is evenly distributed over the surface of the plate with a notched trowel. The layer thickness should be about 20-30 mm.
	Styrofoam bonding. We apply the plate with the applied adhesive composition to the surface of the wall, level it and press it. Hold the insulation for about a minute until the glue sets.
	Seam filling. Voids larger than 20 mm are filled with plates and wedges cut from the insulation. We blow low-modulus polyurethane foam into small gaps.
	Surface grinding. Using a special grater, we process the surface of the foam to give it a roughness. Such processing will facilitate further finishing of the insulated wall.
	Anchor drilling. Using a drill on concrete or brick, we drill holes for the installation of mechanical fasteners. As a rule, the plate is fixed in the corners and in the center - this ensures sufficient fixation strength. We select the length of the drill in such a way that it can pass the heat-insulating layer and penetrate into the base by about 60 mm.
	Mechanical fixation. We insert plastic dish-shaped dowels into the drilled holes. We fix each dowel with a nail or locking screw. We embed the dowel caps into the foam by about 1-2 mm.
	Strengthening corners. At the corners, joints of planes and other areas we glue protective pads made of perforated metal. Some will protect the foam and finish from damage during mechanical stress. When gluing, we sink the perforation and the mesh along the edges of the corner into the adhesive solution, after which we level the corner with a spatula.
	Gluing plaster mesh. We apply an adhesive solution to the surface of the foam. We lay a plaster mesh on it and drown it with a spatula - so that the composition comes out in the cells. We smooth the surface, completely hiding the grid.
	Surface leveling. If necessary, we apply an additional layer of mortar on top of the mesh, which we first level with a spatula, and then with a plaster trowel. After the initial drying, we overwrite the putty, preparing the surface for decorative finishing.

Conclusion

Now you are convinced that the good performance properties of polystyrene, together with low cost, make it one of the best options for facade insulation. In addition, the simple foam mounting technology, which is clearly shown in the video in this article, will be easy to perform even for beginners.

Do you have any questions? Feel free to ask them in the comments!