Installation 

How to insulate walls. How to insulate the walls of the house from the inside: materials and their advantages. Frame wall insulation technology

September 7, 2016
Specialization: Capital construction works(laying the foundation, erecting walls, constructing the roof, etc.). Internal construction works (laying of internal communications, rough and fine finishing). Hobbies: mobile communications, high tech, computer technology, programming.

I know various ways do-it-yourself home energy efficiency improvement. However, their use in a city apartment is limited by the design features of a panel skyscraper and the lack of equipment for high-altitude work. Therefore, most often it is necessary to insulate the room from the inside.

Today I will tell you what kind of wall insulation are from the inside, how they are correctly installed and the final interior decoration.

Advantages and disadvantages of internal insulation

The greatest scope for engineers and insulation specialists opens up when it is necessary to insulate a private house. There you can mount heat-insulating material indoors, on the facades of the building and even build multilayer walls with insulation inside.

As for a city apartment, and especially one located on a high floor, the choice of solutions is limited here. You will have to fix the insulation for the walls inside the room or use expensive high-rise equipment. The latter option for self-implementation is unacceptable, so most resort to the first.

I want to note a few more disadvantages of internal insulation, because of which experts resort to it not very willingly:

  1. With the internal placement of thermal insulation material, the dew point shifts, and moisture can condense under the insulation (between the enclosing and additional wall), causing the appearance of fungus. In addition, due to constant wetting, the building envelope will collapse faster.

  1. The warming layer inside the room does not allow the wall to warm up, having accumulated thermal energy. As a result, thermal inertia decreases, that is, the microclimate inside the room will depend more on the air temperature outside.
  2. The heat-insulating layer has a multilayer structure, and for effective work it is necessary to use a heater with a thickness of at least 10 cm. Therefore, an insulating cake reduces the already not very large usable area in an urban dwelling.
  3. The technology of mounting insulation on the inner surfaces of the walls does not allow high-quality joining of the plates on the walls and floors, therefore, cold bridges often appear in these places, reducing the effectiveness of thermal insulation.
  4. Some types of heat-insulating materials release chemical compounds dangerous to humans into the air, which accumulate in a residential area.

However, internal insulation has its advantages:

  • use climbing equipment, aerial platforms or scaffolding don't have to;
  • work on thermal insulation can be done at any time of the year, regardless of the air temperature outside;
  • insulation measures can be combined with the process decorative finishes apartments, which will save a certain amount of money.

To make the most of the pros and minimize the cons, you need to choose the right heat-insulating material for the job. Therefore, in the next section I will talk about the types of insulation for walls from the inside.

The choice of insulation

Before determining the best insulation, I will list possible options, which can be used for thermal insulation of the apartment:

  1. Mineral wool. An effective and environmentally friendly insulation, which is often used in private construction.
  2. Polyurethane foam. Sprayed polymer foam, which, covering the walls of the apartment, forms a homogeneous waterproof heat-insulating layer that well protects the room from heat loss.
  3. Heat insulating paint. Minus - a very high price.
  4. Styrofoam. Sheet cellular insulation, which has excellent technical characteristics in terms of application for internal insulation of an apartment, but at the same time it is very cheap.

In my opinion, the best choice would be expanded polystyrene, or, as it is popularly called, polystyrene (although this is not very correct). In addition to the low price, which I have already mentioned, this thermal insulation material has several additional advantages, which I will describe in the table below.

Characteristic Description
Good heat keeping properties The material has a very low coefficient of thermal conductivity, therefore, for effective thermal insulation of a city apartment, it is enough to use sheets with a thickness of 5, maximum - 10 cm.
hydrophobicity Insulation from sealed polystyrene cells practically does not absorb water, therefore, during installation and operation, it does not need additional waterproofing.
light weight Thermal insulation does not exert a large load on the enclosing structures of the house.
Antiseptic The material has antiseptic properties; mold, fungi and other microorganisms do not develop on its surface and inside.
Durability If the operating conditions are observed, the insulation retains its properties for at least 30 years.
Ease of installation Expanded polystyrene is easily mounted on insulated surfaces without the use of complex engineering equipment.

Of course, sheet building polystyrene foam is not without drawbacks, but they are fully justified by the affordable cost.

So, as we found out, polystyrene-based foam (marked PS) by the non-press method (marked B) is best suited for work. To increase fire safety, it is necessary to purchase a heater with flame retardants added to the raw mass (marked C).

As for density, a material with a density of 25 kg per cubic meter is suitable for thermal insulation of walls inside the room, since after installation it will not experience external mechanical loads.

In the photo - wall insulation with fire properties with a density of 25 kg per cubic meter.

I'll sum it up. For internal wall insulation, PSB-S-25 expanded polystyrene should be used. The manufacturer of the material is absolutely not important.

  • all granules of the material are approximately the same size;
  • length, width, and most importantly - thickness, individual sheets of polystyrene foam must match;
  • the foam should not emit unusual odors that indicate a violation of the production process;
  • the packaging of the material must be marked, and together with the expanded polystyrene, the seller is obliged to provide the necessary technical documentation.

Tools and materials

In addition to polystyrene foam, the following additional materials are needed:

  1. Primer for concrete with antiseptic properties.
  2. Glue for foam.
  3. Plastic dowels with wide caps.
  4. Polyurethane foam adhesive.
  5. Fiberglass alkali-resistant mesh.
  6. Reinforcing corners.

Of the tools you will need a puncher (since you have to drill a large number of holes in a concrete wall) and a grater for working with cement-based adhesives (needed with smooth and jagged edges). And, of course, a standard set of locksmith tools - a hammer, wire cutters, scissors and so on.

Warming technology

How to insulate walls from the inside with foam? The instruction, which is set out below, consists of several sequential steps, which are shown in the diagram:

Step 1 - Preparing the Walls

I always start by preparing the insulated surfaces for work:

  1. I install the necessary engineering communications. Most often we are talking about the air ducts of air conditioners and electrical wiring. Less often - about water supply and sewerage:
    • Air channels connecting the inner and outdoor units split systems, must be laid in pre-made strobes, insulated with polyethylene foam shells, and then puttied flush with the main wall.
    • Electrical wiring should also be laid inside the strobe. There is another option - to fix the wires on the wall surface in polymeric fireproof channels, and then make recesses in the foam plastic, where the wires will hide.
    • Water pipes with detachable connections must not be hidden in an insulating layer and concrete walls, as they may leak. Need to use only plastic products connected by gluing or soldering.
    • Sewer pipes should generally be laid only in an open way.

  1. Eliminate defects in reinforced concrete walls. They must be sealed before gluing the foam:
    • Small cracks should be filed with a grinder and a diamond wheel, and then sealed with mounting foam. After hardening, cut off the excess composition with a knife flush with the wall.
    • Large defects should be repaired cement mortar. If a piece of reinforcement is visible inside the recess, it must be cleaned with sandpaper from traces of corrosion, and then well smeared with a rust converter.

  1. I clean the wall from the remnants of the solution, debris and dust. Be sure to use a perforator or a hammer with a chisel to eliminate the influx mounting solution, which can interfere with the alignment of the styrofoam boards. Dust can be removed with a brush.

  1. ground concrete walls. It is better to do this in two layers:
    • Dilute the primer with clean water in a ratio of 1 to 1 and treat all insulated walls with it. If the volume of work is large, it is better to use a sprayer.
    • The second layer is applied after the first has partially dried. In this case, the primer does not need to be diluted, and for application it is better to use a maklovitsa, with which you carefully rub the primer liquid into the walls.

  1. I do wall markings. It is necessary to mark the horizontal and stretch the guidelines along which the polystyrene foam will be glued:
    • At a height of about 52 cm from the floor (50 cm is the width of the expanded polystyrene sheet), it is necessary to make a notch, after which, using a water or laser level, draw a strictly horizontal line through this mark, along which the first row of plates will be glued.
    • Drill a hole near the ceiling near the corner of the room, where to drive a metal bar. After that, at a distance of 11-12 cm from the wall, tie a rope to it, on which to hang a weight. It hangs strictly vertically.
    • Install a similar rod near the floor, and then tie a rope to it so that it continues to hang vertically.
    • Repeat the operation at the opposite corner of the wall.
    • Stretch a horizontal rope between two vertical ropes. It will serve as a guide for leveling the plates. It can be moved up and down along the guides installed in the corners.

Step 2 - Installation of insulation

Installation of thermal insulation sheets is carried out in the following sequence:

  1. I'm preparing the adhesive. For this, a pre-purchased dry mix is ​​​​used. Mixing solution:
    • A strictly defined amount of water is poured into a clean bucket or trough (indicated on the package with glue), where dry powder is added.
    • The mixture is mixed with a low-speed drill and a mixer attachment.
    • After mixing, the solution must stand for about 5 minutes to start a chemical reaction between the additives and plasticizers that make up the adhesive.
    • After the pause has elapsed, the finished glue is mixed again.

  1. If necessary, I cut sheets of polystyrene foam. The beauty of this material is that you do not need to use complex or expensive equipment to process it:
    • The necessary parts are separated from the pieces of insulation with a hacksaw or sharp stationery.
    • For cutting, you can also use a special nichrome wire, which is heated with electric current. Thus, it is possible to cut polystyrene foam not only across, but also along.
    • After trimming, the edges must be processed with a foam plastic grater (with holes) or coarse sandpaper.

  1. I smear a sheet of polystyrene with glue. This should be done immediately before installation on the wall, but in this paragraph I will talk about the general rules:
    • First, it is necessary to form a roller from the glue along the edges of the slab with a thickness of about 2 cm. At the same time, it is necessary to ensure that the cement composition does not fall on the end of the polystyrene foam (where the tile joint will be).
    • Then you need to put 2-3 lumps of glue in the middle of the sheet, which will hold the plate on the wall.
    • Carry out test bonding. Attach the plate to the wall, press down, and then tear off. The distributed adhesive must cover at least 40-60% of the expanded polystyrene board (the exact figure is indicated in the thermal insulation documentation).

  1. I glue sheets of polystyrene foam. Work begins with the bottom row, which is mounted strictly along the drawn line and continues from top to bottom:
    • Insulation boards at internal and external corners are installed using the gearing method. This means that the slab of the top row should hang over the slab of the bottom row and so alternately up to the very top.
    • The vertical seams of the bottom row should not coincide with the seams of the top. They should be offset relative to each other by at least 15 cm.
    • Vertical seams should not be a continuation of the window and door opening. In the corners, specially cut L-shaped parts should be installed.
    • It is better to start gluing the second and subsequent layers after the first row of foam boards in the room is glued, and the glue has hardened for at least a day.

  1. I seal the seams between the foam sheets. This is done with polyurethane glue. This operation eliminates the appearance of cold bridges in the insulating layer, which worsen the heat-preserving properties of the walls. The operation is carried out taking into account the following features:
    • Seams with a thickness of 1 mm or more are subject to sealing.
    • If the gap between the plates is large, you first need to insert a small piece of polystyrene foam there, and only then fill everything with polyurethane foam.
    • The foam dispenser should be positioned so that it fills the gap throughout the thickness, and not just on top.
    • After hardening, the protruding parts of the adhesive are cut flush with the insulating layer using a clerical knife.

  1. I fix the polystyrene foam with dowels with caps. I used a dowel with a plastic driven core, which has a lower thermal conductivity:
    • A ruler is installed on the puncher so that after passing through the foam and glue, the drill is deepened into the reinforced concrete wall to a depth of 6 cm.
    • Holes are drilled through the foam. Considering that the insulation will not experience wind loads (as on the facade of a building), to securely hold the thermal insulation, it is enough to use 2-3 dowels per sheet of expanded polystyrene.
    • After making a hole, a dowel is inserted into it, and then the core is clogged in such a way that the hat is slightly recessed into the polystyrene foam, without rising above the surface.

Step 3 - Reinforcement

Finishing expanded polystyrene with a reinforcing mixture is carried out as follows:

  1. Window and door blocks are made out. For this, special parts are used that are glued to the window trim or door block. The scheme of work is as follows:
    • The surface of the window or door block is cleaned of debris, dust and adhesive residue, if it somehow ended up there.
    • The door trim or window block is degreased with any alcohol-containing solution.
    • The reinforcing corners are cut to the desired length at an angle of 45 degrees so that they can be joined to each other.

  • A strip of protective paper is removed from the adhesive layer, after which the reinforcing corner is glued to the door or horse block.
  • After that, a small layer of glue is applied to the slope of the window or door, a mesh is applied to it, connected to the corner, which is then embedded in the glue with a trowel to work with the plaster mortar.
  • Are issued outside corners window and door opening. For this, perforated corners with a grid installed on both sides are suitable. They also need to be pressed into the pre-applied glue and smoothed out with a trowel.

  • At the corners of windows and doorways kerchiefs are glued to the walls - pieces of a grid measuring 20 by 40 cm at an angle of 45 degrees to the horizontal.
  1. I carry out continuous reinforcement of the surface of the walls with fiberglass:
    • Glue is applied to the surface of the foam, after which it is evenly distributed over the entire surface of the wall from ceiling to floor using a notched trowel. You need to cover the wall with glue to the width of one roll of fiberglass.
    • After the glue is distributed, the fiberglass mesh is pressed against the wall surface and embedded into the reinforcing mixture with a plaster trowel.
    • Additional applied on top a small amount of glue, which is distributed over the surface of the insulation so that the mesh is completely hidden by the solution.
    • Adjacent mesh sheets are mounted overlapping each other at a distance of 10 cm.
    • In inside corners In the room, the grid must be positioned so that it runs onto another wall at a distance of 10 cm. When smoothing it, it is necessary to work only with the blunt end of the grater, making outward movements so as not to tear the grid.

  1. I leave the wall to dry. It is necessary to dry not until full strength is gained, but only by 75%, so that the surface can be cleaned (more on this in the next section). If the room temperature is too high, I recommend slightly dampening the surface to ensure proper dehydration of the solution.

Step 4 - Decorative trim

Now you can move on to the next step:

  1. I clean the surface of the wall with a grater. In no case should this be done with sandpaper, as you can tear the mesh installed on the polystyrene foam. You can act only with the end of the plaster grater, cleaning off the influx of the solution.

  1. I measure the wall with a rule to detect and eliminate irregularities. Problem areas must first be marked with a pencil, and then additionally sealed with a reinforcing compound.
  2. I putty the surface with a starting putty. After the reinforcing layer has completely dried (the exact time required for this is indicated on the package with glue), it should be puttied with a starting putty in order to eliminate minor defects in the base.

  1. I level the wall with finishing putty. This composition will eliminate the slightest irregularities in the base and prepare the walls for further painting or wallpapering. After the putty has hardened, you need to clean the walls.
  2. I prime the walls. Priming at this stage will reduce the absorbency of the surfaces and improve adhesion to the paint or wallpaper paste.

After that, you can carry out the final decorative finish.

Summary

Now you know how to use expanded polystyrene to increase the energy efficiency of your own apartment. By the way, this material is quite versatile, so you can use it to insulate the attic from the inside with your own hands. You can learn more about this technology in the video in this article.

You can leave your opinion about the information presented in the material in the comments.

Insulation of the walls of the apartment may be required in multi-apartment panel houses, since it is in them that biggest problems due to the small thickness of the partitions. If the walls do not protect the premises well from frost, then the load on internal system heating rises, as do the bills public utilities, there is an unfavorable microclimate.

Rules and main disadvantages of wall insulation from the inside

Internal insulation compared to the outside whole line shortcomings that you need to know about before starting work on the installation of thermal insulation. Due to the location of the insulation on the inside of the apartment, the wall does not accumulate heat and it will not be possible to completely avoid heat losses, in any case they will be up to 15%. Also, when insulating from the inside, the "dew point" will be located between the installed thermal insulator and the wall. Therefore, condensation can accumulate on the wall, which can cause fungus and mold to appear in the rooms.

Correctly in an apartment from the inside it is much more difficult than from the outside, and making even minor mistakes during installation work will lead to the fact that the wall will still freeze, which is why building, facing and heat-insulating materials will be subject to increased wear.

To prevent condensation on the walls, it is necessary to install a high-quality vapor barrier, it is she who protects the insulation from moisture and significantly extends its service life.

For work, we need a high-quality vapor barrier film and construction waterproof tape (for sealing the seams of the installed vapor barrier). As thermal insulation, materials with low vapor permeability should be used. It is very important that the vapor permeability of the insulation is lower than that of concrete walls. This will allow moisture to evaporate outside, and not inside the apartment.

When installing vapor barrier and insulation material, they should be very carefully coated with glue and fixed tightly on the wall so that there are no cavities between them. Walls before installation work should be primed with special compounds that protect surfaces from fungus and mold. They also help to improve the adhesion of the materials to be mounted.

It is also recommended to provide in an insulated apartment high-quality ventilation. Standard natural ventilation it is unlikely to be enough, therefore it is necessary either to install a forced air circulation system, or to equip window frames with special valves through which fresh air will enter the rooms.

It is extremely important to correctly calculate the required thickness of the installed thermal insulator. The thickness of the insulation must correspond to the material of the walls and the climatic conditions in the region. If the insulator layer is too small, it will not be able to reliably protect the apartment and its residents from the cold. Particular attention during installation must be paid to the joints of the plates, there is a high probability of the occurrence of "cold bridges".

Can mineral wool be used for thermal insulation?

Mineral wool retains heat well and is able to "breathe", that is, let air through, however, due to temperature changes, this property can adversely affect the microclimate of the room and cause condensation to appear on the walls.

To prevent this from happening, it is necessary to choose materials of high density. Mineral wool is not as dense as polystyrene foam and urethane foam, therefore, experts recommend either abandoning such a heater, or buying only those mineral wool slabs that have the highest density comparable to the characteristics of foam plastic.

Before installing the mineral wool, it is necessary to install a high-quality vapor barrier. If an insufficiently reliable waterproofing material is chosen, or it is installed with violations, over time, a fungus will necessarily appear under the facing layer, to combat which it will be necessary to carry out complex and costly repair work.

Expanded polystyrene - advantages and installation rules

Styrofoam, penoplex and polystyrene foam are much better suited for mounting on concrete walls than mineral wool. They have all the necessary characteristics to ensure a comfortable microclimate in the apartment. The most important advantage of expanded polystyrene is its low thermal conductivity, but it has other positive traits, providing the possibility of using it for mounting on walls inside:

  1. 1. Light weight, smooth surface. These characteristics allow you to perform installation work with minimal labor and securely fix the material on the wall with glue.
  2. 2. The possibility of pre-treatment. Before installation, expanded polystyrene can be cut with an ordinary construction knife.
  3. 3. Strength. Expanded polystyrene can withstand strong tensile loads and even significant compression, which is very important, given the high loads on the thermal insulator during strong temperature changes and shrinkage of building structures.

Even the cheapest extruded polystyrene foam almost does not absorb moisture, which means that when installing it, you can refuse to install a vapor barrier layer. To isolate the joints of the plates during repairs, it is enough to seal them with mounting foam. Foam can also be used when installing polystyrene foam boards on walls. When expanding, it will fill all the gaps between the installed insulation and the surfaces to be treated, make the fastening reliable and completely sealed. Modern extruded polystyrene boards have spikes and grooves that simplify their installation.

To fix the foam, you can use not only glue, but also special fasteners in the form of fungi. After the panels are located on the wall, they are drilled through and the fasteners are driven through the holes into the walls. Such fastening is very reliable and can be used in concrete and brick houses. After completion of installation, all cracks and seams of the plates must be sealed. Various facing materials can be mounted on top of the thermal insulation, including plaster and drywall sheets.

When choosing expanded polystyrene for insulation, it is necessary to take into account not only the advantages of this material, but also its disadvantages. For example, polystyrene foam is not able to provide in rooms high-quality sound insulation In addition, it is highly flammable and can release substances hazardous to humans during combustion.

Internal thermal insulation with polyurethane foam

Polyurethane foam - polyurethane foam, foamed polymer, which is sprayed for insulation using special equipment. To mount such a heat insulator, a wooden crate is installed on the wall, acting as support guides for the sprayed material, it is also used for further installation of the cladding.

The main advantage of polyurethane foam is that, when sprayed, it fills all the bumps, cracks and joints in the walls, creates a sealed, seamless surface that fits snugly against the wall without voids and cavities. In other words, the installation of polyurethane foam completely protects the apartment from "cold bridges" and from the possibility of condensation.

Polyurethane foam is moisture resistant material with low thermal conductivity. When installing it, it is not at all necessary to cover the walls with layers of hydro and vapor barrier. With its help, it is very easy and quick to insulate any walls, however, it is impossible to perform such work without specialized equipment, which is the main disadvantage of this method of insulation.

It is impossible to create a heat-insulating coating for walls from polyurethane foam with your own hands; you will have to seek help from professionals who are well acquainted with the insulation procedure and who have the technical means necessary to perform such work. Some companies are engaged in leasing equipment for processing walls with polyurethane foam, this is a great opportunity for self-insulation, requiring much less financial costs than purchasing expensive equipment.

Cork - a non-standard tool for dealing with cold walls

Cork is an insulating material produced in the form of slabs and rolls of cork wood. It is environmentally friendly and completely safe for users, which is very important for finishing living rooms. Thanks to excellent technical specifications cork wood with it, you can simultaneously insulate the apartment, provide it with high-quality sound insulation, and also increase the attractiveness internal walls.

Cork insulation can only be installed on perfectly flat surfaces, therefore, before installation, the walls should be prepared for repair. First you need to completely remove old facing materials from the surfaces, and then cover the walls with a primer with an antiseptic that can protect the room from biological contamination - fungus and mold.

Next, the walls are leveled. For this, plaster or plasterboard sheets are used. When leveling drywall, use a waterproof adhesive and mounting foam so that after installing the plates between them and the wall there are no voids and cavities left. After fixing drywall sheets on the wall they should be additionally fixed with plastic fasteners such as "fungus" or anchors.

When the drywall or plaster base is dry, you can proceed with the installation of cork insulation. Natural wood sheets or cuts roll material carefully smeared with special glue, after which they are tightly applied to the base. Cork wood insulation is also a full-fledged facing material that does not require subsequent finishing.

In addition to ease of installation and visual appeal, the positive characteristics of cork wood materials include the fact that they have a small thickness. That is, the installation of insulation will not greatly reduce the area of ​​the rooms to be lined, which is very important for small city apartments.

Penofol - foamed polyethylene to improve the performance of the apartment

Penofol - foamed polyethylene, the thickness of which is from 2 to 10 mm, which is sold in rolls. On the one hand, this material has a foil coating that provides heat reflection inside the lined premises. Before installing penofol, the surface of the walls must be prepared in exactly the same way as for the installation of cork wood cladding, after which the material can be fixed with construction tape.

Penofol must be installed in such a way that its foil side faces the room. Such an installation will turn the room into a kind of thermos, perfectly retaining heat. Penofol strips for installation must be cut into lengths along the height of the room. The strips must be installed like wallpaper - end-to-end. The joints are additionally glued with special adhesive tape, which also has a foil surface.

Penofol is a high-quality insulation of an apartment that can be done by hand, but heavy facing materials cannot be attached to it. For further decoration of the walls of a cold apartment, it is necessary to install a wooden or profile crate on top of the foam foam layer, on which plasterboard sheets can be attached. Drywall is faced with plaster, wallpaper or paint.

When installing drywall sheets, it is necessary to leave small gaps (about 5 mm) that will ensure good air circulation and prevent condensation and accumulation of moisture on the insulation. Penofol is one of the best materials for thermal insulation, which can be used alone or together with other heaters, for example, with expanded polystyrene.

Professionals recommend carefully examining the walls in the apartment before installing any facing material. Only if no traces of mold are found on the surfaces, you can proceed to installation work. If the walls are infected, they must first be cleaned and protected from the recurrence of the fungus, and only after that proceed to the insulation.

External walls are the most important element of the building, which, in addition to performing a load-bearing function, also protects the interior of the house from adverse weather conditions. Modern multilayer structures make it possible to rationally use energy carriers, significantly save on heating and building maintenance, which cannot be said about the “traditional” brick or panel buildings of the Soviet period. But the time has come to count the money - all that remains is to insulate what we have. In the article we will consider topical issues of wall insulation from the inside.

Is it possible to insulate the room from the inside at all? In professional circles, disputes on this subject are serious. Manufacturers of thermal insulation materials and practicing builders have not come to a consensus about whether it is possible to insulate from the inside, this is a painfully risky undertaking. At the same time, everyone agrees that the best option in all respects is the thermal insulation of the facade.

What should a simple layman do, who is facing the problem of serious heat loss through the outer walls, because the information is extremely contradictory, and there was no choice, and there is no choice - there is no way to insulate from the outside. There can be many reasons for this situation: the apartment borders on unheated premises (elevator shaft, corridors, stairwells), behind outer wall there is a deformation seam between two closely standing houses, the facade has an expensive finish, the building is an architectural monument or is located in the historical part of the city, the authorities regulate urban development in their own way - they simply prohibit the insulation of facades.

Some clarity on this issue, of course, is brought by GOSTs and SNiPs operating in the countries of the post-Soviet space, which strongly recommend that “cold” layers be placed indoors, which are characterized by high thermal conductivity and minimal vapor permeability - concrete, brick, stone. The place for the insulation is clearly defined - this is the outer side of the building envelope. However, even regulations have exceptions. For example, in P3-2000 to SNiP 3.03.01-87 "Design and installation of thermal insulation of enclosing structures of residential buildings" in section No. 7, devoted to design solutions, it is said that it is allowed to insulate the walls of individual apartments in multi-storey buildings if the installation of a heat insulator from the side facade is impossible for certain reasons.

What are the disadvantages of warming from the inside

Let's see why it is the internal insulation that has so many opponents, what pitfalls await us. There are several negative points, some of them are not critical, you can put up with them, while others can have very serious consequences and make you approach the issue of warming from the inside with extreme caution:

  1. A heat insulator placed on the inner surface of the wall “eats up” the usable area of ​​\u200b\u200bthe dwelling. For example, if in a room measuring 4x5 meters we apply 50 mm of insulation on two outer walls, we lose 0.5 m 2 of the total twenty squares.
  2. Work on the insulation of walls from the inside can only be carried out in a completely vacated room that has been decommissioned for some time.
  3. The installation of insulation on the walls does not end there. In addition, it is necessary to take a number of serious measures to protect the enclosing structures from condensation and organize additional ventilation.
  4. If everything is done correctly, then this method of insulation cannot be cheap, as it might seem at first glance.
  5. It cannot be said that the technology is simple and accessible. We repeat if everything is done correctly.
  6. But the most important thing is the special thermophysical processes that take place in the walls, insulated from the inside. All the well-known "horror stories" related to the internal insulation of residential premises are indeed quite common. The occurrence of water streaks, the spread of fungus and mold, the destruction of finishes and load-bearing elements - all these are the consequences of an illiterate change in the thermal envelope of the room, which entailed violations of the moisture state of the walls.

A secret covered with cotton wool. What happens in a wall insulated from the inside

All processes of interest to us take place not only in sub-zero temperatures, but also in the autumn-spring period with a slight plus outside the window. There is nothing surprising in the fact that the main problems with internally insulated walls appear in winter, when serious differences between the temperature outside and inside the room are possible. It is the outer walls, or, as they are also called, "enclosing structures", that are a buffer that receives the blows of the elements.

It is necessary to consider the effect of temperature on multilayer structures only in combination with changes in their humidity. In fact, water is our main enemy. It is she who, freezing, expands and destroys building arrays, as well as their junctions; it is she, penetrating into the layer of insulation, that nullifies its thermal insulation characteristics; it is a prerequisite for the existence of harmful fungi and microorganisms.

What is the relationship between temperature regime and wall moisture, you ask? Here we come close to considering the phenomenon when, under certain conditions, water vapor from the air reaches critical saturation, and water appears on cold surfaces in the form of condensate. The temperature at which condensation forms on structures is called the "construction dew point". It directly depends on the relative humidity of the indoor air. The higher the humidity, the higher the dew point, the more it approaches the actual temperature (at 100% they are equal). To calculate the exact dew point, a rather complex formula is used. The set of rules SP 23-101-2004 "Design of thermal protection of buildings" contains a table of dew point temperature for various values ​​​​of humidity and indoor temperature.

If we take into account sanitary regulations for the operation of residential premises (GOST 30494 and SanPiN 2.1.2.1002), the normalized temperature in the dwelling should be about 20-22 ° C, and the relative humidity of the air should not exceed 55%. According to the table, the dew point will be +10.7 °C. This means that where there is such a temperature in a multi-layer wall, moisture from the air can turn into water and fall out as condensate.

Obviously, with significant changes in the outside temperature, the dew point moves inside the wall, closer or further from the interior space of the room, since on the one hand we heat the wall, including heating in winter, and from the street it is cooled. This is a kind of tug of war.

The specific place in the building envelope where condensate can fall depends largely on the thermal characteristics of the wall, the thickness and materials of each layer, and their relative position.

1 - wall without insulation; 2 - wall with insulation from the inside

If the structure is not insulated, the dew point is inside the wall, thermal cameras show that it radiates heat, the room is cold even when the heating is running at full power - we lose heat.

With the external location of the heat insulator, the array of the load-bearing wall warms up completely, accumulates heat, and the dew point shifts to the insulation zone, which must be freed from the moisture formed in it - hence the technology of ventilated facades arose.

The wall, insulated from the inside, completely freezes through, as it is “fenced off” by a heat insulator from internal heat. This significantly reduces the service life. bearing walls. The dew point in most cases is located on the inner surface of the building envelope, but with increasing temperature environment can be shifted into the wall array. As a result, moisture forms between the wall and the insulation, which worsens its thermal insulation characteristics. Freezing, it can destroy the adhesive connection of the heat insulator layer with the base. There is a threat of wetting the wall, the appearance of fungus and mold.

How to minimize the negative effects of wall insulation from the inside

SP 23-101-2004 "Design of thermal protection of buildings" states: "It is not recommended to use thermal insulation from the inside due to the possible accumulation of moisture in the thermal insulation layer, however, if such an application is necessary, the surface from the side of the room must have a continuous and durable vapor barrier layer ".

So, our task is to make the wall warm and dry, for this we need to protect the place where the dew point is located as much as possible from the penetration of water vapor. For this, a whole range of measures is being taken:

  1. The insulation layer is closed with high-quality vapor barrier films with sealing of joints and junctions.
  2. A heat insulator with the lowest vapor permeability is used. Ideally, if it is less than that of the building envelope. The steam can then be gradually expelled to the outside.
  3. A layer of insulation is glued with a minimum gap from the wall, preferably not in a "beacon" way, but on a comb.
  4. Insulated walls are lined with moisture-resistant drywall.
  5. Additional air exchange is organized to reduce the humidity in the room. Mechanical ventilation systems are used, windows are equipped with control valves.

It is important to completely eliminate possible cold bridges. The fact is that by installing a heat insulator from the inside, we are not able to insulate the junctions of the ceilings and internal walls with the enclosing structures. That is why insulation must be carried out with access to adjacent walls and ceilings, then they should also be carefully isolated from vapors and, possibly, constructively decorated with boxes, false columns.

What thermal insulator to use

Mineral wool

Practice shows that in the vast majority of cases, people insulate walls from the inside with mineral wool. It is placed without any vapor barrier between the racks of the frame of drywall systems. In addition, rolled wool is often used, which is not intended for vertical structures, with a clearly insufficient coefficient of thermal resistance. Such insulation is done easily and very quickly, it is incredibly cheap, but not at all effective, and even harmful.

Note that cotton wool, to put it mildly, is not very suitable for warming from the inside. Fans of this material enthusiastically call it "breathable", but in our case this is just its main drawback. Not only is there easy access to the location of the dew point through the fibers, but the ability of mineral wool to absorb moisture also causes many problems. Of course, you can count on the fact that cotton wool will never get wet, use special mineral plates, which, in terms of thermal characteristics, are identical to expanded polystyrene foam. You can carefully glue them and try to organize an absolutely tight vapor barrier from the inside of the room. But the risk of moistening the insulation and the inner surface of the walls remains, then all efforts will be reduced to zero, the moisture will find a way out into the room, streaks or fungus. This is because the vapor permeability of any building envelope is several times worse than that of cotton wool.

Some craftsmen attempt to completely seal mineral wool slabs - they also use an inner layer of vapor barrier, make “pillows”, sealing cotton wool in a polyethylene sleeve. But other problems arise: the insulation is not fixed to the wall - gaps appear at the locations of the dew point, the plates are difficult to fit together without damaging the shells, the technological chain becomes more complicated.

Styrofoam and XPS

At the moment, expanded polystyrene is one of the best materials for insulating walls from the inside, so from year to year it is increasingly used both in Russia and in many European countries. The popularity of expanded polystyrene is explained by its excellent operational and thermal characteristics. Its undeniable advantages are:

  1. Low thermal conductivity.
  2. Minimal water absorption and vapor permeability.
  3. Ability to withstand high loads, both compressive and tensile.
  4. Ease of cutting and installation;
  5. Lightweight plates.

So, using foamed or extruded polystyrene foam, we can increase thermal insulation structures with the minimum possible thickness of the insulating layer. Not only do the foam and XPS do not absorb moisture and do not lose their insulating properties, they also do not allow water vapor to pass into the dew point zone, an additional film vapor barrier will simply be superfluous. Of course, for this it is necessary to reliably isolate the joints of the plates and their adjoining to the enclosing structures. This is fairly easy to do using polyurethane foam. Moreover, some manufacturers produce plates with a stepped edge, due to which the insulation is joined without any gaps at all. Expanded polystyrene can be successfully mounted on the wall according to the facade system, using adhesive compositions and fixing with dish-shaped dowels at the same time.

As we have already noted, the adhesive layer also performs an insulating function; polyurethane adhesive in the form of foam has proven itself especially well. The high strength of the material allows options for finishing insulated walls in a wet way directly over the heat insulator, without the use of frame technologies, while it is simply impossible to overload the wall due to the low specific gravity of the material. So, square meter an insulating layer made of expanded polystyrene is 2-2.5 times lighter than a similar thickness layer made of mineral wool.

There is one small drawback - polystyrene foam has poor soundproofing properties. The problems of the possible destruction of the heat insulator at temperatures above 80 degrees and the insufficient resistance of expanded polystyrene to the effects of many organic solvents, in our case, are perhaps not critical.

polyurethane foam

This durable and lightweight material is also well suited for insulating walls from the inside. It has excellent insulating properties due to its cellular structure. The coefficient of thermal conductivity of polyurethane foam is from 0.025 W / (m K), which is one of the best indicators. The pores of polyurethane foam are filled with air or an inert gas, each such cell is hermetically sealed. That is why moisture is not absorbed into the material and does not pass through it - this is an excellent waterproofing of the building envelope.

Low thermal conductivity, minimal moisture absorption, maximum vapor barrier - that's what we need. But this is not all, the polyurethane foam coating receives special properties due to the unusual method of its application. The fact is that it is applied by spraying a liquid two-component substance that foams on the treated surface and hardens within a few seconds.

  • Polyurethane foam perfectly "sticks" to any bases, including ceilings, there is no need to use fasteners, which are cold bridges.
  • The coating forms a single whole with the wall, not giving moisture from the room the slightest chance to penetrate into the dew point area.
  • The heat-insulating layer is monolithic, without seams and cracks. By spraying the substance, it is possible to insulate curvilinear, semicircular walls without problems.
  • Polyurethane foam is applied very quickly. Foaming of the insulation is carried out at the place of work, therefore, due to the small volume of the liquid starting material, the costs of delivery and storage of materials are minimized.
  • The polyurethane foam layer can be plastered facade technology using kapron mesh.

Other materials

There are other, often "innovative" wall insulation materials on the market, whose manufacturers claim their outstanding properties. However, all of them are a little cunning, hiding obvious shortcomings or hushing up about serious problems in the implementation of the corresponding technological chains. For example, warm plaster in terms of its thermal characteristics is several times inferior to foamed materials, moreover, it is hygroscopic and vapor-permeable. Foiled polyethylene foam has a very low thermal conductivity, but only under one condition - it must be mounted in such a way that there is an air gap between the insulation and the wall, as well as the sheet cladding. Make two sealed gaps, fix the material well, while it is almost impossible to isolate the joints and junctions with high quality. Therefore, in most cases, polyethylene strips are simply nailed to the outer wall with dowels, with the inevitable loss of the declared characteristics. Ceramic-based liquid thermal insulation with a layer thickness of 1 mm replaces 50 mm of mineral wool - this is what its manufacturers say. A thermal conductivity of 0.0016 looks fantastic to say the least, especially considering that ultra-thin coating consists of ceramic bubbles filled with air. But ceramics have a thermal conductivity of 0.8-0.15, and air - 0.025. "Thermal paint" - the material is new and has not really been studied yet, but examples of non-working insulation apartment buildings has already. Perhaps, under certain conditions, such an insulator has the right to exist.

How thick should the insulation be?

The right choice of thermal insulation materials is one of the key aspects of competent wall insulation from the inside, now it is necessary to determine its thickness:

  1. First, using the formula R \u003d D / L (where D is the thickness of the structure, and L is the value of the thermal conductivity of the material), we calculate the actual heat transfer resistance of the wall without a heat insulator. For example, if we have a building envelope made of bricks with a thickness of 500 mm, then the thermal conductivity resistance will be: R = 0.5 / 0.47 = 1.06 m 2 ° C / W.
  2. Now we can compare this indicator with the normalized one. For example, the heat transfer resistance for building envelopes in Moscow and the region should be at least 3.15 - the difference is 2.09. It needs to be filled with insulation, since the thermal conductivity of the structure consists of the sum of the coefficients of its layers.
  3. The required thickness of the insulation is calculated by the formula D = L·R. For example, if we want to use polystyrene foam (L = 0.042), then we need D = 0.042 2.09 = 0.087 - an 87 mm foam layer. Naturally, it is better to overestimate the minimum values ​​​​and apply 100 mm of expanded polystyrene, then there is a chance to transfer the dew point inside the layer of completely waterproof insulation.

Summing up

Wall insulation from the inside is an extreme measure in a situation where there is no way to fix a heat insulator from the side of the facade. Properly performing such work is technologically quite difficult. Internal insulation is not as cheap as it seems at first glance, so it will most likely not be possible to save significantly.

It is possible to formulate the basic requirements for high-quality wall insulation from the inside:

  1. It is necessary to organize a hermetic vapor barrier of the wall.
  2. The thickness of the insulation must not be less than the calculated one in order to ensure the normalized thermal conductivity of the building envelope for a certain climatic zone.
  3. Be sure to take measures to improve the ventilation of the room.
  4. The heat insulator should be glued with a comb or continuous strips.
  5. It is also necessary to insulate areas of ceilings and partitions adjacent to the outer walls.
  6. It is better to sheathe the outer walls with moisture-resistant drywall on a metal frame.
  7. To ensure the tightness of the lining, do not place sockets, switches, lamps, sconces on it.
  8. Adjacencies of sheet materials to the enclosing structures must be sealed with acrylic or silicone.
  9. U-shaped brackets are mounted to the base only through insulating gaskets.
  10. All work on wall insulation should be carried out after they have been treated with antifungal compounds. The base must be completely dry. Wetting the structure from the outside should be excluded in advance - all roofing, facade and window work must be completed, all systems should function properly.

It should be noted that not always the reason that the room is cold is the poor thermal insulation of the outer walls. It is worth paying close attention to the thermal characteristics of the floor, ceiling, window blocks. Maybe this is where the cause of all the troubles lies, and perhaps the problem is in the incorrect operation of the heating or errors in its design. If this is the case, then even perfectly executed wall insulation will not bring the desired effect, and the temperature in the room will rise only by 1-2 degrees.

If heating bills in winter cause you a panic attack, and the walls of the house constantly “sweat”, then some miscalculations were made during construction, and it's time to think about warming. This is not a simple and expensive matter, which is why it is so important to carefully approach the choice of materials.

In this article, we will tell you how to insulate the walls of the house from the inside, and compare several popular types of insulation to make it easier for you to make a choice.

Main characteristics

Before proceeding to the choice of how to insulate the walls from the inside of the house, it is necessary to clearly understand what qualities these materials should have. To one degree or another, all heaters have the same set of quality characteristics, but the difficulty of choosing lies in the fact that different materials have them in different proportions.

So, let's figure out what qualities must necessarily be present in a heater:

  • Degree of thermal insulation. Miscellaneous materials have varying degrees of isolation, and it often makes no sense to overpay for extra features when they are not really needed. This parameter largely affects the final cost, so it makes sense, if not to save money, then pay for other criteria.

  • Vapor permeability. This indicator is very important, especially if condensation constantly forms on your walls, which, if it does not evaporate, will eventually turn into fungus or mold. The insulation must allow moisture to evaporate freely from the surface of the wall.
  • dimensions. With the same heat capacity, heaters can have different thicknesses. Since the topic of our article is how to insulate the walls inside the house, the thinner the insulation sheet, the better, since this will allow you not to hide the cherished centimeters from total area rooms.
  • No cold bridges. The problem with many heaters is that cold bridges always form at the junction, which can adversely affect the finish. It is better to give preference to the material that has tight joints that will not freeze through.
  • Ease of attachment. Wall insulation is a simple process, and in most cases it does not make sense to involve specialists, and all the work can be done by hand, but there are also materials that may require not only professional skills, but also special expensive equipment for installation.

  • Shape saving. Some types of low-quality insulation may lose their shape over time, and as a result, their quality. It is expensive and difficult to redo repairs, so it is better to carefully select a material that will retain its original shape throughout its entire service life.