Whether the house will be warm even in a big frost depends largely on the condition of the walls. Warm air, heated by batteries and heaters, leaves the room through cracks and poor insulation. To solve this problem in a multi-storey building, significant efforts are required, for which there may not be time, effort, and money, both for residents and representatives of the local administration or service company. Therefore, it is easier for owners to create comfortable conditions on their own and insulate their apartment.

When choosing how to insulate the walls of an apartment from the inside, one should start from the material for erecting and decorating the walls, the shape of the room, and its size. It depends on which insulation will effectively protect the room from the cold, and which one will not cope with such a function.

When wall insulation is not possible from the outside

In accordance with building standards, the insulation of the house must be external. This method is more reliable than the internal one, it does not sometimes reduce very valuable square meters of living space and evenly protects the building from hypothermia. But there are situations when external insulation is not possible.

There are two main ones:

  1. The design of the facade does not allow it to be insulated from the outside;
  2. The building is recognized as a historical heritage, and it is forbidden to change its appearance even if insulation is necessary due to insufficient temperature according to SanPiN standards.

If external insulation is present, but its effectiveness is not enough, you will also have to deal with the insulation of the walls from the inside. In general, this list is exhaustive, with the exception of special cases.

How to insulate the walls of an apartment from the inside: an overview of suitable materials, selection rules and basic insulation installation technologies

Is it possible to insulate the walls inside the room

There is no direct ban on insulation. There are also no documents regulating how to insulate a cold wall from the inside in an apartment. The owner independently chooses the material, method of fastening, place for insulation. If the resulting insulation does not protect well from the cold, condensation forms on it, then the owners will also have to solve the resulting problems on their own.

Note! Poor-quality insulation will create an unfavorable environment in neighboring rooms, including in other apartments. Therefore, having decided on the device of internal insulation, remember the level of responsibility that you place on yourself.

Disadvantages of internal insulation

Insulation of the apartment from the inside is convenient in its own way, because it can be done independently, without waiting for approval from the administration. However, in addition to the existing advantages, this method of increasing the thermal insulation performance of a dwelling has a number of disadvantages. These include the following:

  1. Any violation of technology during internal insulation threatens to cause a number of troubles associated with negative changes in the microclimate in the apartment. These include, for example, the formation of condensate. It appears on the surface between the insulation and the wall on which the material was mounted;
  2. Lack of proper warming effect. This problem is eternally relevant, because due to incorrect installation of heat-insulating material, there will be no benefit from it. And, as you know, many apartment owners, seeking to save on work, resort to self-assembly, not having even the slightest idea about the technology;
  3. Reduction in living space. This drawback is especially relevant in the case of warming small apartments, in which every extra meter of rooms counts;
  4. Fairly high price. Of course, wall insulation does not cost millions, but given the current financial situation of ordinary citizens, it can hit the pocket. If you fully follow the technology, purchasing all the necessary materials, and even hire workers, then the thermal insulation will become, if not golden, then gilded.

How to properly insulate a house from the inside: a few universal tips

There are several «instructions» on how and with what to insulate the walls in the apartment with your own hands. They are known as “Our Father” by every more or less competent builder. They come down to this:

  1. Prepare the wall for insulation correctly: close the cracks, treat them with an antifungal and anti-mold compound;
  2. Consider air humidity and temperature fluctuations in the room both when choosing materials and when performing work. This is especially true for the kitchen and bathroom;
  3. Mount the insulation only on dry, even walls, apply glue with a frequent comb;
  4. Isolate all joints between the insulation panels so that it does not freeze through;
  5. If there are cold bridges, then take this into account when calculating the required thickness and thermal conductivity of the material. If you do not take into account these nuances, there may not be any sense from warming.

Note! The materials that insulate the wall from the inside in the apartment must have a vapor permeability lower than the main wall. So water vapor will go outside, and dampness will not linger on the finish.

Several aspects of proper insulation

Choosing how to insulate the walls of the apartment from the inside, you need to choose the right material. And this is perhaps the most important aspect of proper insulation, with the exception of the installation technology, which was already mentioned above.

When choosing thermal insulation, you should pay attention to three important parameters of insulation: vapor permeability, weight and thickness. Weight and vapor permeability depend on the material of the walls: heavy materials with low vapor permeability can be hung on a concrete surface, and only light and permeable to water vapor can be hung on a cinder block surface.

The thickness of the material is those centimeters of living space that the insulation can take away. However, sometimes, they still have to be sacrificed in order to increase the comfort of living.

Features of cold wall insulation from the inside

In winter, the walls are in contact with warm air inside the room and cold outside. If the building is designed correctly and all building standards are met, then the wall material will always be warmer than outdoor air. This gives two positive effects: the walls in the apartment remain warm, and the moisture goes outside, where it then evaporates.

If you insulate the walls of the apartment from the inside, then the section of the outer wall will become colder than it was before. After all, the heat-insulating material will prevent the penetration of heat to the outside, keeping it inside the apartment, and not allowing it to heat the wall anymore.

The cold wall, at the same time, will be in contact with the insulation, and condensation may appear at the point of contact. To avoid this, wall insulation must be combined with a year-round ventilation device or the installation of special filters on windows that will perform a ventilated function.

How to insulate the walls of an apartment from the inside: an overview of suitable materials, selection rules and basic insulation installation technologies

Dew point: physics of the phenomenon

The ratio of humidity and temperature at which vapor turns into droplets is called the dew point. Under natural conditions, fog, dew, hoarfrost and clouds are formed in this way.

If water vapor is at the dew point, it is called saturated. The amount of steam at which it becomes saturated depends on the temperature: the colder it is, the less steam is needed. To indicate how close the vapor is to the dew point for a given temperature, use relative humidity, which is expressed as a percentage. 100% is saturated vapor that is ready to fall out as fog or dew.

In construction, the dew point is not a point on the temperature scale, but an area where water vapor can become saturated. This point must always be outside the wall on the street side. To achieve this effect in winter, you need to carefully calculate the vapor permeability and thermal conductivity of the surfaces. In any weather, the outer wall of the building must be warmer than the surrounding air so that the steam evaporates from its surface and has time to dissipate before it falls in the form of frost. It should be borne in mind that in cold weather the dew point approaches the wall, and in warm weather it moves away.

If the temperature difference between the wall and the outside air is insufficient, the dew point will move closer to or inside the wall. Moisture condenses on the surface or between layers of material at the points of contact between cold and warm air. This leads to negative consequences, which are:

  • In the destruction of materials;
  • Freezing walls in frost;
  • The appearance of mold and fungus.

The best materials and methods of thermal insulation: selection criteria and an overview of market leaders

The easiest and cheapest way to insulate a wall is to hang a carpet or stick thick wallpaper. But he is the most ineffective. A much more effective method to insulate a wall from the inside in an apartment is to install a heat-insulating material that is attached (glued) to the wall and subsequently, as a rule, covered with a finish. The thickness of the insulation layer, at the same time, is calculated in such a way that the dew point remains outside in any weather. However, not only the thickness of the material matters, but also the technical qualities of the insulating products.

Materials for insulation should be characterized by the following properties:

  • The effectiveness of thermal insulation, which is largely determined by the coefficient of thermal conductivity. The lower it is, the better;
  • Safety for the health of people and pets;
  • Non-combustibility (as far as possible);
  • Safety for the environment;
  • Small thickness;
  • Optimal cost.

On a note! When choosing how to insulate a cold wall from inside the apartment, you need to pay attention not only to the characteristics of the material, but also to its “compatibility” with the base of the walls.

That is, for example, in the case of the thermal insulation of a brick wall, it is better to use one insulation, and in the case of a concrete one, another.

Types of insulation

We wondered how to insulate the walls of the apartment from the inside with your own hands and what material to choose? There are several options. The most popular of them are mineral wool or the so-called “foamed” heaters. Both materials are quite light, effectively protect against cold and noise, and their vapor permeability is suitable for any walls.

However, of course, these are far from the only possible options, and we will pay attention to an exhaustive list of the most effective and popular thermal insulation materials.

polyurethane foam

This material is available in the form of foam, as well as sheets or blocks of pre-hardened raw materials. The sprayed foam can be applied to the surface of any shape and configuration, including complex ones. The material is sold in cans, each of which is accompanied by detailed instructions for use.

Advantages of polyurethane foam:

  • Does not leave gaps, seams and glues;
  • Does not require complex installation work;
  • Doesn’t get wet;
  • Complies with all safety requirements;
  • Differs in low consumption (if you use a can);
  • Applied in a thin layer;
  • It has increased efficiency, which is especially important when using foam blocks, which instead of air bubbles contain an inert gas.

Of the shortcomings, it is worth highlighting:

  • The high price of the material and the need to purchase or rent equipment for spraying;
  • Pickiness to storage conditions (polyurethane foam cannot be left in direct sunlight for a long time, they degrade the protective properties);
  • The presence of requirements for the timing of the subsequent finishing of polyurethane foam. After hardening, you need to start finishing as soon as possible.

liquid ceramics

Liquid ceramics is considered one of the most innovative and modern materials for insulation. It is a thick paint or paste, which is enough to evenly apply to the wall. This is enough to get good thermal insulation without seams and joints. Among the advantages, manufacturers indicate: a thin layer that does not take up living space, low load on structures and ease of application.

The main disadvantage of thermal paint is its high cost. As for the consumption of material, it depends on the method of application: if you use a roller or brush, it will be more, if you take an airbrush — less.

Reviews about this type of thermal insulation are contradictory, since such paint has only recently appeared on the construction market.


Penofol is produced in the form of rolls of soft insulation. It is based on polyethylene foam, to which foil is welded on one or both sides. In a single-layer penofol, the second side can act as an adhesive layer, with which the material is glued to the wall.

The disadvantages include complex installation technology. Under the insulation, you need to prepare a crate, on which you should subsequently attach the penofol with the foil side inward (if there is one). On top of it, it is necessary to mount another crate, on which a plasterboard layer (GKL) is attached, and only after that — wallpaper is glued or another finish is made.

Despite the thinness of the layer of the insulation itself, this is not far from the best option when deciding how to insulate the corner wall in the apartment from the inside under the wallpaper. Obviously, two crates will take up too much space.

On a note! Penofol is not glued overlap, but end-to-end. In this case, the resulting gaps are glued with adhesive tape.


Polyfoam is another type of polyethylene foam. Unlike penofol, it is denser and does not have an additional foil layer. In terms of thermal insulation efficiency, the material is equal to half the thickness of the brickwork. Poliform does not require preliminary leveling and plastering of the walls.

Just like penofol, this material is mounted end-to-end, and not overlapped. The joints, again, are glued with tape. Only, unlike a competitor, polyform does not require a sheathing device and installation of drywall on top of the material. And, by the way, it can be used as a substrate for wallpaper.

mineral wool

Mineral wool is one of the most popular thermal insulation materials. It is produced in the form of panels that are mounted on a flat wall or on a crate.

The material is effective, inexpensive and durable. Of the shortcomings, it is worth highlighting the need for careful preparation of the walls. But a more serious problem is a significant shift in the dew point inside the room. The condensate quickly destroys the mineral wool, because of it it can freeze through.

Styrofoam insulation

Expanded polystyrene is a block insulation that needs to be mounted on a flat wall. The thickness of the blocks is relatively large, so the reduction of living space when using this material cannot be avoided. Apart from the need to level the wall, the installation of expanded polystyrene can be called easy and fast. At the same time, its thermal insulation efficiency is high, and the cost is relatively low.

Of the shortcomings, it is worth noting the complex “relationship” with moisture. Expanded polystyrene does not absorb it, but significantly shifts the dew point into the room. Condensation accumulates between it and the wall, gradually destroying the base material. Without good ventilation, the wall will quickly begin to turn black and moldy.

Extruded polystyrene foam

Extruded polystyrene foam differs from its counterpart in greater strength and durability. It is produced under several brands, the most famous of which is penoplex. It shifts the dew point less, less often causes condensation.

Both types of polystyrene have a common drawback — flammability. It is absolutely impossible to use them in a wooden house. When burning foam, substances harmful to health and the environment are released into the air.

Types of insulation

Use of Styrofoam

Polyfoam is very light in weight and easy to install. It can be cut with an ordinary knife and give it the desired shape. It is also one of the cheapest materials, so when choosing how to insulate a wall in an apartment from the inside under wallpaper or other material, you should pay attention to foam plastic.

And now it will be fair to point out the shortcomings. So, it is worth remembering that condensate will constantly accumulate between the wall and the foam, which needs to go somewhere. Therefore, it is not recommended to attach a non-breathable finish, such as tiles, over the foam. Instead, it is better to use wallpaper or, say, plaster.

The use of keramoizol

Keramoizol is a specific liquid coating. It is not afraid of moisture, temperature changes and fire. You can work in any weather, but only with good ventilation. Keramoizol is suitable for any surfaces: concrete, brick, wood, foamed varieties of the first. The main disadvantage of this thermal insulation material is the price.

Penoizol insulation

Penoizol (izolon) surpasses mineral wool in terms of thermal insulation characteristics and takes up much less space. The material is sold in liquid form and applied to the surface with a sprayer. It can be used not only as heat, but also as sound insulation during fixation, for example, on inter-apartment partitions.

The main problem of penoizol is the lack of strength. It is impossible to attach anything to a wall treated with penoizol. When it dries out, voids may appear that will become bridges of cold. Contact with air and mechanical damaging factors is strictly contraindicated. Polystyrene can insulate the walls of the apartment from the inside only under the wallpaper.

Using Astratek

Astratek is another liquid wall insulation. In the composition, it contains ceramic hemispheres and a binder. It is applied by brush, roller or airbrush like regular paint. The insulation is effective, it does not require preliminary preparation of the walls. However, Astratek is very expensive, which is clearly not in its favor.

How to insulate walls in a panel and monolithic house?

The walls of the panel house pass water vapor well and cool down easily in winter. Therefore, residents often complain that the house is cold. If there is no high-quality external insulation, you have to solve the problem from the inside of the apartment.

For thermal insulation of panel walls, materials with high vapor permeability are most suitable: expanded polystyrenes, mineral wool, liquid mixtures. The same recommendations apply to monolithic walls.

Wall insulation using the «electric floor» method

If it is not possible to fix the insulation on the wall, you can lay a “warm floor” on it. Then the wall will become a source of heat, not cold. It is best to do this under the window or near the balcony door, where it blows most often.

The advantages of this option of thermal insulation are that there is no need to install heaters that will take up space and create a fire hazard.

It is also worth noting that when creating a “warm floor” on the wall, the effect of constant and uniform heating is achieved. But it is worth remembering that when installing an electrical system, electricity bills will increase.

Installation of insulation on brick walls

Almost any thermal insulation, including heavy ones, can be attached to a brick wall. Sometimes cork is used, which is a natural, durable and wear-resistant material. But it is worth considering that the cork takes up a lot of space, so if it is scarce, you should pay attention to light foam materials.

On a note! The vapor permeability of a brick is relatively low, which is why almost any material will be in place.

Features of room insulation in a panel and brick house

In a room, it makes sense to insulate only one wall — the one that faces the street. If this is an end room, then two walls will need to be protected from the cold. The choice of insulation thickness depends on the size of the room: the smaller it is, the thinner the layer should be.

A universal option is mineral wool or foam materials. In a brick house, it is better to use those insulations that have a minimum coefficient of thermal conductivity due to its high brick index.

Reviews and recommendations from builders and ordinary people

Reviews on the network are extremely diverse. Builders have their favorite and least favorite materials. The most controversial opinion has developed about liquid insulation. The undisputed leaders of opinions are mineral wool and polyfoam, they are effective and easy to install. To understand how to work with them, it is not necessary to be a specialist, because even photos and videos from the network can help.


Wall insulation from the inside of the apartment is an extreme option, relevant if the room is very cold, and external thermal insulation cannot be expected for certain reasons. In order for the internal insulation measure to be beneficial, not harmful, you need to choose the appropriate material and calculate all insulation parameters. Another important condition is good ventilation and a clear and unquestioning observance of the installation technology.


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