Can styrofoam be used as insulation? Styrofoam as a heater - a complete analysis

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 cracks 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

Do you want to get cozy and warm housing, the temperature in which does not depend on the vagaries of the weather? Then you should insulate the walls from the outside with foam. Don't know where to start and how to get started with this work? In this case, study this article - it will give you answers to your questions.

First, let's get acquainted with the material that will be discussed in the article. Styrofoam is a polymeric insulation produced in the form of white boards. The material has a pronounced granular structure, and each individual grain contains many voids filled with gas. It is their presence that gives the foam excellent thermal insulation qualities. For other material properties, see the table.

Table. Polyfoam - the main characteristics.

Important! When buying foam, pay attention to the fact that it has flame retardant additives, and the pores in the grains contain non-combustible carbon dioxide.

The advantages of polystyrene include:

• low cost;
• good thermal insulation qualities;
• small mass;
• ease of processing and installation;
• unattractive to bacteria and fungus;
• high durability.

As for the shortcomings of the foam, there are two of them. The first is the combustibility of the material. The second is low vapor permeability, which, in the event of an error in the design or installation of insulation, can lead to mold on the main wall.

The main task performed by insulation is to shift the dew point outward. Consider three building options.

1. In the first case, there is only a wall without any insulation. The dew point is located inside the material, there is a significant temperature difference between its outer and inner sides. As a result, a lot of heat escapes through the wall, condensation forms in the house, and the service life of the material drops significantly due to dampness.
2. In the second case, the insulation is located from the inside. The dew point shifts to the area between it and the wall. Heat losses are significantly reduced, but dampness remains. There is also a risk of mold appearing between the insulation and the wall.
3. In the third case, the insulation is located outside, the dew point is shifted beyond the wall of the house. The latter is now not subject to dampness and does not lose heat.

Styrofoam prices

Styrofoam

Preparing exterior walls for insulation

Construction work related to the insulation of the facade of the house with polystyrene foam begins with the preparation of the walls. They need to be cleaned, leveled, primed, etc. All these actions are described in more detail in the step-by-step instructions below.

Step 1. To work at a height exceeding human height, build scaffolding. You can make them yourself from the timber and boards available on the site, but it is safer to use factory-made products.

Scaffolding prices

Scaffolding

Step 2 Inspect the walls for various defects. Coat cracks and holes, chip off the build-up of mortar. Prepare openings for water and gas pipelines and other utilities.

Step 3 Treat the wall with a deep penetration primer. Since the house in the example is made of aerated concrete blocks, two layers will be required. For the first time, the primer must be diluted by adding water from a third to a half of the total volume.

Important! Primer treatment in two layers is necessary not only for aerated concrete, but also for other porous materials, such as foam blocks and sand-lime bricks.

Step 4 Apply a second coat of primer, but not diluted with water.

After completing the preparation, proceed to laying the polystyrene foam boards. In this case, their mounting on the wall will be combined - both glue and dowels with "umbrellas" are used.

The process itself will include:

• laying polystyrene foam for insulation on ordinary walls of the house;
• on window and door openings;
• at the corners;
• on the space under the roof of the cottage.

For all processes from this list, separate step-by-step instructions have been compiled, which can be found in the subsections of the article below.

Working with Regular Walls

Let's start warming the house from the outside with foam. Let's start with a relatively simple one - mounting the first row of polystyrene foam boards and laying them on ordinary walls.

Step 1. Measure how smooth the walls of the house you are insulating are, identify the presence of differences in thickness. To do this, use either a stretched thread or a laser level.

Step 2 Set a mark at the bottom of the wall and draw a line from it along which the first row of polystyrene foam plates will be laid.

Important! In this case, when insulating the walls from the outside, the foam is laid directly on the foundation - it is even enough for this. In other situations, install a special aluminum support profile before installing the EPS boards.

Step 3 Mix the adhesive for mounting the polystyrene foam insulation. To do this, dilute the dry mixture in water. Choose the proportions based on the instructions printed on the glue package. Stir the solution using a mixer or a drill with an appropriate nozzle, working at low speed.

Step 4 Prepare polystyrene boards for the first row of insulation. In this case, a cutout is created in each of them, as in the diagram below. Cutting polystyrene foam plates is carried out using a special table with a hot nichrome thread. In the absence of such equipment, use a hacksaw with a fine tooth.

Step 5 Apply adhesive to the first block. To start, make a thin strip around the perimeter by pressing the trowel into the Styrofoam. Then add more mortar, bringing the layer thickness to 25-30 mm. In the center of the block, apply several adhesive dots, their number depends on the area of ​​the insulation element.

Application of the second layer, more voluminous. In the process of working with it, be careful - the glue should not get on the ends of the foam block

Prices for Ceresit glue

Glue Ceresit

Step 6 Perform a test laying of the styrofoam block. The purpose of the event is to find out what proportion of the total area is occupied by glue. To do this, lean the block against the wall, and then set it back. Depending on the thickness of the insulation layer, the adhesive contact area should be 40-60% of the total.

Step 7 On paper or directly on the wall, prepare the marks on which the polystyrene blocks will be placed. Lay the slabs in the same way as brickwork - the top row is shifted to the side relative to the bottom so that the vertical seams do not match. The allowable distance is from 15 cm, otherwise the seams will become "cold bridges". You can get acquainted with the layout of the foam blocks in the images below.

Step 8 Proceed with laying the first block - apply the adhesive on it as shown earlier, lean against the marked place and lean it. Then align the position of the product. This will help you with a thread stretched along the upper edge of the first row of blocks, and the usual building level.

Important! Use small pieces of Styrofoam as pads to support the first row of blocks.

Step 9 Following the same principle as in the previous step, lay the second, third and subsequent blocks of the first row.

Step 10 Then lay the remaining rows of foam insulation. You can read about how to do this at corners and openings in the following subsections of the article. Dock the blocks to each other tightly, fill the gaps with polystyrene foam glue, polyurethane foam or thin pieces of material.

Step 11 After the glue or mounting foam has dried, with which you filled the joints between the blocks, cut off the excess with a construction knife.

Step 12 Use the rule to determine how even the insulation layer turned out. Protruding areas grind with a special grater.

Corner insulation

Installation of insulation at the corners occurs according to the following scheme - on one side, the block extends beyond the wall boundary at a distance equal to the thickness of the block installed on the second side. On the next row, the order of location of the foam insulation elements is reversed. By a similar principle, blocks are installed on internal corners. For a better idea, check out the images below.

Now let's look at how the installation of foam blocks on the corners of the building actually takes place.

Step 1. Mark one of the foam blocks. Select the part that will go beyond the border of the wall at the corner and the part that will be glued to the surface.

Step 2 On the part of the block that is glued to the wall at the corner, apply the mortar mixed earlier. Perform this operation carefully - the glue should not get on the other part of the product that you previously separated using the markings.

Step 3 Lean the block against the wall so that the adhesive adheres to the surface. Align horizontally and vertically, be sure to use the building level.

Prices for building levels

Building levels

Step 4 Measure how long a block you will need to install on the other part of the corner. Cut off the excess with a fine-toothed hacksaw.

Step 5 Apply glue to the back of the foam and place the block on the other side of the corner. Connect it tightly to the product that you installed a few operations ago.

Step 6 Cut off the protruding part of the first block with a hacksaw. At the end, you should have a right angle without any defects. If there is a gap between the blocks, then cover it with special glue for polystyrene foam or mounting foam. By the same principle that was outlined in this instruction, work with the rest of the external and internal corners of the building.

Insulation of window / door openings and walls next to them

To begin with, consider the principle by which the walls are insulated near the doorway. Here the main task for you will be to provide enough space for opening and closing. There are two options for mounting the frame and door.

1. The door is installed flush with the outer side of the insulation layer. In this case, you need special fasteners for it and supports in the form of channels. You can see the diagrams of their installation in the image below.
2. The door is installed flush with the main wall. As a result, it turns out to be "drowned" in the insulation. To ensure the normal opening of the door, the polystyrene foam at the edges of the opening has to be filed.

Imagine the process of laying insulation near the doorway in the form of step-by-step instructions. In this case, the option is considered with the installation of the frame and the door itself at a level with the main wall.

Step 1. Pick up the right number of blocks and file them from the edge with a regular hacksaw with fine teeth.

Step 2 Install a frame in the doorway, if this has not been done before.

Step 3 Degrease the surface of the door frame.

Step 4 Prepare the required number of profiles for thermal insulation of openings. Unpack them, measure and cut. In this case, the edges of the profile adjacent to the corners of the openings must be cut at an angle of 45 °.

Step 5 Remove the protective tape from the adhesive layer of the profile and fix it on one side of the opening. Make sure the profile fits snugly against the surface.

Step 6 Glue the profiles on the other sides of the opening in the same way. In the corners, join them tightly to each other with cuts made at an angle of 45 ° in one of the previous stages of work.

Step 7 Prepare fiberglass strips. Their width should be equal to the thickness of the insulation layer plus 10 cm for fastening to the main wall. In this case, the strip is cut off from a single mesh roll.

Step 8 Along the perimeter of the opening, apply a strip of adhesive mixture 10 cm wide on the wall.

Step 9 Rest a strip of fiberglass mesh with one of the edges on the glue applied in the previous step. Press the material against it, literally “drown”.

Step 10 From above, apply another layer of glue to the part of the mesh leaning against the wall.

Step 11 Repeat the previous mesh operations for the other sides of the doorway.

Step 12 Install foam blocks with cut edges around the perimeter of the opening.

The situation with window openings is approximately the same - the block itself with a frame and glass can be installed both in the depth of the opening and on its edge. In the first case, a gap appears between the outer layer of insulation and the window, which is closed by narrow strips of foam. They are laid on the glue in the inner surfaces of the opening.

In the second option, the window is mounted on the edge of the opening, with the frame adjacent to the insulation layer on the outer wall. This method is more effective in terms of thermal insulation.

It is also worth saying that the joints of the polystyrene blocks should not coincide with the joint of the window block with the opening. Therefore, along the perimeter, the insulation is installed in the form of products with L-shaped cutouts. There are two options for how to do this, and they are presented in the images below.

The process of insulating walls with foam plastic near window openings is in many ways similar to that for a doorway. Here is a step by step guide.

Step 1. Install the window block, move it closer to the edge of the opening and fix it well there.

Step 2 Remove the protective film from the frame and degrease the latter.

Step 3 Glue a special profile around the perimeter of the frame.

Step 4 Apply a 10 mm wide adhesive strip along the perimeter of the profile on the wall.

Step 5 On the glue applied in the previous step, fix the fiberglass strip according to the same principles as for the doorway.

Step 6 Cut out the blocks in accordance with the diagrams outlined in the images in this section of the article. Fasten around the perimeter of the opening.

Important! When fixing the foam plastic under the window opening, make a slight slope necessary to install the ebb.

As for the space under the roof, here the difference from working with ordinary walls is that it is necessary to pre-cut blocks with different and complex shapes from the foam.

Installation of mounting umbrellas on foam plastic

For a more reliable connection of the insulation layer with the main wall, mounting "umbrellas", also known as dish-shaped dowels, are used.

Step 1. Determine the length of the dowel you need. It consists of the thickness of the insulation layer (in this case it is 200 mm), the adhesive layer (15 mm), the length of the expansion part of the dowel (60 mm) and another 20 mm of reserve. Also decide which of the schemes shown in the image below, you will mount the fasteners.

Step 2 Unpack the plate dowels, check if the parameters of the product match those you need.

Step 3 Prepare a drill with a hole depth limiter, adjust the latter to the value you need.

Step 4 Mark the points for the plate-shaped dowels and drill holes there.

Step 5 Insert the leg of the dowel into the hole so that the head is flush with the surface of the foam. Then use a special nozzle on the drill and tighten the spacer part of the fastener, then close it with a protective cap.

In some dish-shaped dowels, the expansion element is not twisted, but clogged. You can see an example of how to work with them in the images below.

Some builders believe that dish-shaped dowels in foam insulation are "cold bridges." They deal with this problem in the following way: using a special cutter, they cut out a cylindrical recess in polystyrene foam, insert fasteners there and fix it. Then the dish-shaped dowel is closed with the foam cover cut earlier.

Prices for popular models of rotary hammers

Perforators

Video - Insulation of the facade of the cottage with polystyrene foam

Insulation reinforcement

On the installation of expanded polystyrene blocks, the process of wall insulation from the outside is not completed - the material must be protected with a reinforcing mesh and plaster mixture.

Step 1. Prepare a plaster-adhesive mixture of dry powder and water. Choose the proportions based on the recipe printed on the package. Mix the mortar with a construction mixer.

Step 2 Start with windows and doors. On the inner surface of their openings, apply a thin layer of plaster-glue mixture and level it.

Step 3 The reinforcing mesh laid on the inner surface of the openings in one of the previous sections of the article is pressed against the adhesive mixture and drowned in it. Smooth everything on top with a rectangular trowel.

Step 4 In exactly the same way as in the previous operation, press the mesh belonging to the previously installed profile to the adhesive layer and drown it.

Step 5 Repeat the previous three steps on all sides of the window opening.

Step 6 At the corners near the openings, apply stripes of the adhesive mixture at an angle of 45°. Then lay a reinforcing mesh on them and smooth it with a trowel. Such areas near the openings are called "kerchiefs".

Step 7 Measure the corner profile to the required length. Apply a layer of adhesive mixture along the outer perimeter of the window, then lean a profile with a mesh against it and the inner surface of the opening and smooth it with a rectangular trowel.

Step 8 By the same principle, install corner profiles on other surfaces of the window opening.

Step 9 Attach a small rectangle or square of reinforcing mesh to the inner corners of the opening, straighten and smooth with a glue mixture.

Step 10 Repeat steps two through nine for each individual window and door opening.

Step 11 Apply an adhesive solution around the perimeter of the house to the bottom of the insulation. Then attach a drop profile there. Install it so that there are no air cavities between it and the insulation. Control the process using the building level.

Step 12 Apply another coat of plaster over the mesh of the drip profile and smooth with a rectangular trowel.

Step 13 According to the same principles as described above, install the corner profile - apply an adhesive layer, attach the product to it, drown it in the net and smooth everything from above.

Step 14 Now proceed to reinforcing the entire surface of the walls. Make cuts from a roll with a mesh length corresponding to the height of the insulated walls of the house.

Step 15 On top of the polystyrene foam, apply a layer of plaster-glue mixture and smooth with a notched trowel.

Step 16 Lay a sheet of reinforcing mesh on top of the adhesive layer, press it and cover it with another layer of mortar on top. Carefully smooth everything - irregularities and cavities with air are unacceptable.

Step 17 In the same way, lay the next piece of mesh side by side. Between it and the previous one there must be an overlap of at least 100 mm.

Step 18 Let the glue mixture dry a little (but not completely!) and scrape off any bumps.

Step 19 Using the rule, search for concavities on the adhesive layer applied over the insulation. Then align them by adding a little more mixture in the right places.

Step 20 On the finally hardened adhesive mixture, make another leveling of the surface - puttying.

The easiest way to insulate a house is to sheathe it with foam. The material is inexpensive, installation is easy to do on your own, the energy-saving effect is obvious. And in order to protect such a skin from the harmful effects of the environment, you need to choose a suitable coating for it. Read more.

After the putty has hardened, the insulation of the walls from the outside with foam plastic can be considered complete. Then you just have to apply the finishing decorative finish in accordance with your tastes and preferences.

Styrofoam (or expanded polystyrene) is a synthetic building material that is widely used for construction and repair work. Styrofoam as a heater has found its application in the insulation of internal and external walls of buildings.

Properly installed polystyrene foam has a number of advantages, due to which it enjoys well-deserved popularity among construction companies and private developers.

Styrofoam characteristics

Before using expanded polystyrene for facade insulation, you need to choose it correctly. The foam used as thermal insulation must necessarily contain flame retardants - substances that prevent it from igniting.

Their presence is indicated by the letter “C” in the abbreviation (PSB-S) or the letter “R” if the material is foreign-made. Equally important are indicators such as density and thickness. To insulate residential buildings from the outside, slabs of five centimeters wide are usually used, no more.

Depending on the type of foam, its density can vary from 15 to 35 units. And since the foam is a rather warm material, its density should not be very high. To insulate the walls of the house, it is enough to take a heater with a compression density of 15 or 25 units. Density 35 is used for floor insulation.

In addition to density, foam is characterized by the following qualities and characteristics:

Insulation of a brick wall with foam

You can insulate the walls with foam plastic both inside and outside. However, most often the insulation of a brick wall is carried out outside. External thermal insulation allows you to shift the freezing point, which prevents the penetration of cold into the house. The walls of the house should be heated by internal heating. When installing the foam from the inside, the brick wall will be isolated from the inside, which will interfere with its heating.

As a result, the "dew point" will shift between the wall and the polystyrene foam. On the inner surface of the walls under the insulation, moisture will begin to accumulate, impregnating the walls and freezing in cold weather. As a result, all this will lead not only to the freezing of the house, but also to the rapid destruction of the insulation and the brick wall itself.

Therefore, it is advisable to fix foam insulation boards on the outside of the facade. But in this case, it must be necessarily covered with a layer of plaster, this will protect the material from sunlight, thereby extending its service life, and also give the structure the necessary strength.

Pros and cons of foam insulation of a wooden house

The question is often asked: “Is it possible to insulate the walls of a wooden house with foam plastic?”. Among experts, two opposite opinions can be found on this matter: some argue that it is possible, others are categorically against it. Let's try to figure it out.

One of the reasons why many speak out against the insulation of a wooden facade with foam plastic is its low vapor permeability, due to which the wood can rot. At the same time, there are many people who have taken the risk of insulating their wooden house with this material, and are satisfied with the result.

One of the main advantages of wood is its ability to "breathe". This is one of the main advantages of building a country wooden house. In order not to lose this quality, the thermal insulation of the facade should be carried out with caution. The result of improper insulation can be not only insufficient air flow into the room.

Proper thermal insulation technology implies that the vapor permeability of building materials should increase towards the street so as not to impede the release of fumes from the house.

If this rule is violated, moisture will condense on a denser material, which will lead to wetting of the insulation, the formation of condensate and, as a result, rotting of the wood. That is why, when choosing a heater for your wooden facade, pay attention to the vapor permeability of building materials.

As can be seen from the table, the vapor permeability of expanded polystyrene is much lower than that of the walls of a wooden house. From this we can conclude that it is undesirable to insulate wood with foam, unless you find this material with a higher vapor permeability.

But what does practice tell us? Many people, despite the recommendations or simply not knowing about them, insulate wooden facades with foam plastic and are quite satisfied. The question arises where the condensate goes.

It should be noted here that the rate of decay directly depends on the amount of moisture evaporating from the house. If the room is equipped with a good ventilation system, then the harm from a small amount of fumes, of course, will be less. However, if you insulate a wooden bath with foam plastic, the result will be obvious in the coming years.

The main reason why polystyrene as a heater is so in demand lately is its low cost. That is why, in an effort to save money, many decide to insulate wooden buildings using this material.

However, over time, such savings can become ruinous. As an alternative, it is better to choose mineral wool. It does not create obstacles in the way of evaporation, which perfectly reach the ventilation gap between the insulation and the cladding. The walls "breathe", and you can enjoy life in your wooden house.

Thermal insulation with liquid foam

There is another way of warming - the use of expanded polystyrene in liquid form. Such casting foam is made directly on the construction site and poured into a pre-prepared formwork. Liquid foam can be used to insulate a brick, stone and concrete house.

Thermal insulation technology called "well" masonry is well suited for this material. It provides for a three-layer structure: wall, insulation, additional brickwork. In this case, the insulation is pumped between two layers.

The advantages of liquid foam can be distinguished:

1. High quality material. Filling polystyrene foam does not let cold into the house in winter and heat in summer;
2. Low price. Liquid foam allows you to save on laying and transportation. According to experts, wall insulation using this material is almost two times cheaper than other heaters;
3. Practicality. Pouring liquid foam is several times faster than installing conventional insulation. And the principle of pumping thermal insulation allows you to implement new unusual solutions.

Among modern heat-insulating materials, the most popular is polystyrene foam or, scientifically speaking, expanded polystyrene foam. It is produced in the form of white plates with a wide range of overall dimensions. The material is very light: the weight of one cubic meter, depending on the brand, ranges from 8 to 35 kg.

Properties of foam as a heater

To date, there are various types of heaters on sale. Or another heater?

The wide demand for foam plastic is due, first of all, to low cost. However, this is not its only merit. The low weight of the boards, as well as the fact that they are rigid, in contrast to, for example, mineral wool, ensures ease and speed of installation. Even one person can easily cope with this task without involving any special technical devices, not to mention heavy equipment.

At the same time, the foam is a fairly effective heat insulator: its thermal conductivity coefficient is only 0.04 W / m * C(value for grades with medium density).

The technical characteristics of polystyrene foam as a heater make this material fragile. Depending on the circumstances, this quality can turn into both an advantage and a disadvantage. For example, due to its low strength, the foam is excellent for processing, it can be cut as you like right during installation. On the other hand, when the building is insulated from the outside, the material has to be protected with a metal mesh and a layer of plaster. For the same reason, care should be taken during installation, since a foam board of any thickness is very easy to break.

Being completely synthetic in nature, the foam is not subject to decay, however, for some reason, it is very fond of rodents. Having found at least a slight access to the heat insulator, they quickly gnaw through entire holes in it. But, although interest from rodents is highly undesirable, it is the best evidence of the environmental friendliness of the material.

Another enemy of polystyrene is ultraviolet. In the absence of protection from solar radiation, the material quickly begins to crumble, becoming unusable. Also, the destruction of the foam structure is facilitated by contact with some paints and varnishes.

The use of foam for thermal insulation

Wall insulation

Styrofoam is widely used as a wall insulation from the outside, and in the conditions of a noticeable rise in the price of energy carriers, even the owners of city apartments began to do this.

Styrofoam is screwed to the facade of the building with dowels, then plastered, after laying a metal mesh on top of it.

Another popular option is:

• Styrofoam is laid in the gaps between the bars of the crate, the cross section of which corresponds to the thickness of the plates
• Siding panels are attached to the crate with sealing of the seams with mounting foam

A mandatory requirement for rooms insulated from the outside with foam is high-quality ventilation. This is due to the low vapor permeability of the insulation. For warming rooms with high humidity, for example, saunas, this material is not recommended.

Insulation of basements and plinths

When insulating basements, foundations and plinths with foam plastic, the low strength of this heat insulator should be taken into account. In winter, it will experience significant loads from the freezing soil, which, in the absence of protection, will lead to its deformation or destruction. For this reason, a brick or concrete cladding is constructed outside the heat-insulating layer of foam.

Floor insulation

The environmental friendliness of polystyrene has led to its widespread use inside buildings. For example, it is often used as a heat insulator in floor construction. The foam is laid on top of the waterproofing layer, filling the seams with mounting foam or silicone sealant. Then a screed and a fine floor covering are laid on top of the slabs.

Roof insulation methods

Thermal insulation of roofs by means of polystyrene foam is carried out according to one of two technologies:

• The device is not ventilated (warm) roof. With this method, the roof is covered with 70 mm thick foam boards, which are then poured with bitumen.
• Ventilated (cold) roof device. In this case, the foam is fixed on the inside of the roofing so that there is a ventilated gap through which water vapor will be removed.

Is styrofoam harmful as a heater?

A significant disadvantage of polystyrene is the high danger that it poses in the event of a fire. Manufacturers and marketers position this material as non-combustible and indicate its ability to self-extinguish, which is especially evident in the presence of a flame retardant additive. However, a material does not need to be flammable to be dangerous in a fire.

As experience and numerous tests have shown, exposure to flame and high temperatures provokes thermal decomposition processes in the foam, as a result of which the air, even at a considerable distance from the place of ignition, is filled with a large amount of smoke corresponding in toxicity to substances of the highest hazard class.

The question of the durability of the foam is also controversial. According to manufacturers, the service life of this material is at least 20 years, however, there is no officially approved test method that allows this statement to be confirmed or refuted.

There are a large number of heaters for the house. If you do not like foam, then you should consider other options. For example, which allow you to perfectly protect the house from heat loss. The structure of the material allows the walls to "breathe", therefore, there will be no problems with rotting and the formation of fungus.

Rockwool insulation is essentially mineral wool. If you only need to insulate the ceiling, then we recommend that you familiarize yourself with the process of insulating the ceiling with mineral wool. Installation of this material can be done by hand.

Price

Here is the approximate price for polystyrene foam as a heater of various brands:

• PSB-S-15O (density - about 9 kg / cubic meter): 1050 rubles
• PSB-S-25 (about 15 kg / cubic meter): 1800 rubles
• PSB-S-25T (about 20 kg / cubic meter): 2350 rubles
• PSB-S-35 Light (density - from 21 to 23 kg / m3): 2550 rubles
• PSB-S-35T (density - from 26 to 28 kg / m3): 3050 rubles

Styrofoam is one of the most effective synthetic insulation used for exterior and interior decoration of the house. It quickly gained popularity due to its good performance and began to spread in numerous areas of private and industrial construction.

Composition and structure of the material

The main component of the foam is expanded polystyrene, and the polymer itself in the finished product contains only about 2% (by volume). The rest of the space is occupied by gas (natural or carbon dioxide) enclosed in closed polystyrene capsules or cells. The macrostructure of the material consists of granules a few millimeters in diameter, pressed and then cut into conglomerates of various shapes.

The walls of polymer capsules have minimal porosity, so almost no moisture enters the cells with gas. This maintains the foam's low density and retains its insulating qualities. To reduce combustibility, a number of additives are introduced into the material, which reduce the time of self-burning (without an external source of flame). This increases fire safety under the condition of short-term exposure to fire.

Physical properties of foam

The main characteristics of porous polystyrene include:

• strength - the foam does not have outstanding strength characteristics and is able to crumble and break even with weak mechanical stress. It can be easily damaged with sharp objects or by simply hitting the surface. To reduce the likelihood of destruction, the foam is covered with layers of a harder material that evenly distributes external loads;
• flexibility - expanded polystyrene is weakly amenable to bending influences and can break under them at any time. For the same reason, foam boards are installed only permanently, avoiding any torsional loads;
• thermal conductivity - the presence of gases (natural heat insulators) in hollow capsules provides the material with a low heat transfer coefficient. This is also facilitated by the absence of convection inside the pores due to their small diameter. It will take a long time to completely warm up a piece of foam to a given temperature;
• Tendency to shrink - free-standing EPS boards are susceptible to slight shrinkage caused by gravity. The shrinkage is 1.5-3 mm within six months. At the end of this period, the natural compaction of the material stops;
• thermal expansion - with increasing temperature, the linear dimensions of the plate increase (the process is reversible). Numerical indicators of expansion correspond to approximately 1 mm per 1 m of foam plastic plate with a temperature change of 15-20 ° C;
• vapor absorption - foam plastic is less resistant to diffusion penetration of moisture than to liquid water, therefore, in especially humid rooms, its surface is additionally covered with a layer of metal foil. In its absence, part of the water vapor can penetrate through the layer of material and condense when the temperature drops, which adversely affects the entire thermal insulation system.

Chemical properties

The operational parameters of the material, which determine the durability under the influence of external factors, include:

1. chemical resistance - expanded polystyrene is immune to many substances, except for solvents and oxidizing acids. Mixtures based on acetone, ethers and light hydrocarbons quickly dissolve the foam, leaving no visible traces of it. Styrofoam is moderately stable with alkalis, however, it is still not worthwhile to specifically expose them to exposure;
2. temperature resistance - the foam has a low temperature limit of destruction. Already at 60-70 °C, gases begin to be released from it, which are products of the destruction of the original polymer. At temperatures above 100 ° C, the decomposition of polystyrene occurs especially intensively and is accompanied by an even greater amount of toxic emissions. Severe effects on the body can occur even a few days after inhalation.

The fire safety of polystyrene is interpreted in two ways by supporters and opponents of the material. The first claim about its high resistance to flame, arguing that the ignited foam plastic practically does not support fire without an external source of heat. The second complain about the release of a large amount of gases during a fire, harmful to humans. From an objective view, polystyrene is a rather combustible substance that requires proper handling when decorating buildings.

Video: Styrofoam (polystyrene foam, PPS, EPS). Advantages and disadvantages.

Biological properties of foam

Styrofoam belongs to the group of building materials that are not affected by microorganisms. Due to poor water absorption, mold forms very slowly on the surface of the foam. Fungal infections of expanded polystyrene can be observed only in very damp rooms with no ventilation.

Unlike paper or wood, styrofoam does not break down when mold appears, and mold deposits can be easily cleaned from the surface by hand. The destruction of the insulation, observed for a long time, is not associated with biological factors, but with the action of ultraviolet radiation, heat and oxygen in the air.

The use of polystyrene in repair and construction

Due to the low cost, low density and good thermal insulation qualities, foam plastic is used in all construction areas - from the construction of capital walls to interior decoration. It is often recommended as a roof and under-roof space insulation laid outside and inside the building. To get a truly environmentally friendly and safe building, foam finishing should be approached with great attention.

Ways to use Styrofoam:

• sheathing of the outer part of the walls. The outer foam layer must be covered with a layer of plaster or other durable material in order to avoid destruction during mechanical and solar exposure;
• interior decoration. When building small houses, the fixed formwork method is often used, in which the gap between the walls of foam blocks is filled with concrete. In order to protect the occupants in the event of a fire, the inner layer of foam plastic must be covered with a layer of plaster at least 30 mm thick.
• as a layer between two walls - used in capital construction and is the best construction solution. Such buildings do not have outstanding thermal performance, however, the temperature in them in winter is still higher than in houses without polystyrene foam, and in hot weather the inner surfaces of the walls heat up less. Such an arrangement is safer from a fire point of view, since even with intense fire, the layer will not be able to ignite.

Video: Styrofoam insulation facade. How to choose foam. How to choose a mesh for foam.

Tip: when using foam plastic indoors, heating pipes and hot water supply pipes, as well as electrical wiring without metal corrugation, should not be laid through it. Local overheating at the points of contact between the foam plastic and communications will lead to accelerated decomposition of polystyrene and the release of harmful fumes.

Conclusions: polystyrene is an effective heat-insulating material that is resistant to moisture and does not change its characteristics under normal operation. Due to the poor resistance of expanded polystyrene to high temperatures and the extreme toxicity of combustion products, special attention should be paid to protecting it with non-combustible and fire-resistant coatings. Styrofoam insulation is best used to protect the outside of the walls and thermal insulation in the interstitial space, in order to exclude the possibility of their heating and decomposition.