Significant features of vapor barrier walls in a house made of wood. Vapor barrier for walls - how to make a wooden house warm and cozy? Which vapor barrier is best for walls

Kirill Sysoev

Calloused hands do not know boredom!

Content

The comfort of the home depends on the temperature and humidity level in the room. In a wooden house, this can be achieved through heating and high-quality thermal insulation. In addition, in order to reduce the negative impact of moisture on walls, floors and roofs, it is necessary to control the degree of vapor barrier, and this task is difficult.

What is vapor barrier for?

Excess moisture adversely affects the wooden structures of the house. The steam emitted when using the shower, cooking, washing, wet cleaning is looking for a way out of the room. Since its pressure is much higher than atmospheric pressure, steam presses on the ceiling, walls, floor, which, together with the temperature difference, contributes to the formation of condensate. Slowly impregnating the wooden structure and seals, water deforms and destroys them: the materials rot, become moldy, their performance decreases.

If in the process of preparing the beams for the roof and walls, vapor and waterproofing of materials was carried out, then the boards for the log and floor do not have such protection. In addition, the flooring of the first floor of the house is arranged on the ground, which increases the negative impact of moisture on it. In order to avoid the process of destruction of the structure of a wooden house, you should take care of a reliable vapor barrier. The protective layer will serve as a heater and prevent moisture from contacting the wood, freely releasing air from the room to the street. Thanks to this, the operational life of the house will increase significantly.

Advantages of vapor barrier of wooden houses

Wood (even untreated) has a high degree of thermal insulation and good permeability. The naturalness of this material makes it possible to build houses without fear that harmful vapors will be released into the air of the room. In addition to the advantages, the tree has significant disadvantages. The ability to collect moisture entails a decrease in the level of heat transfer resistance and provokes the decomposition of wood. The appearance of a fungus on the walls and other parts of the house worsens the aesthetic characteristics of the home and can cause various diseases of the residents.

As a result of regular wetting and drying of the wooden structure, the tightness of the joints deteriorates, as a result of which they become ventilated. If there is no vapor barrier for the walls of a wooden house, the materials allow moist air to pass through themselves and retain some of the moisture from it. To improve the working conditions of walls and other elements made of wood, it is necessary to place a vapor barrier at the junction of warm air and cold enclosing structures.

What materials are used

The building materials market offers various types of waterproofing, which have excellent characteristics. As a rule, breathable membranes and films are used to protect the walls of wooden houses from moisture, but there are other types of vapor barrier. What materials are suitable for home insulation and vapor barrier:

1. Ruberoid. The advantage of this type of material for waterproofing is its low cost, however, roofing material is more suitable for laying on the roofs of outbuildings than for protecting the walls of wooden houses. In addition, it is more expedient to use such a tool not as the main vapor barrier, but as an additional layer to more effective materials.
2. Aluminium foil. The film is covered with metal on one side and has a reinforced mesh on the other. Such a device helps to create a vapor barrier inside the room and a layer that reflects heat. To insulate a wooden house, a foil vapor barrier is laid out with a metallized coating. Laying such material on the walls must be done carefully so as not to damage its integrity. If you decide to foil your home, your home will not only be protected from corrosion, but also insulated.
3. diffusion membrane. Vapor-permeable material protects the home from moisture, regulates its amount, due to the ability to pass air (on two or one side). The vapor barrier membrane has a high vapor permeability coefficient, which is due to the microstructure of the material. A significant advantage of the diffuse film is the absence of a ventilation gap between the thermal insulation and the membrane, which ensures the most efficient use of space. Such a vapor barrier for the walls of a wooden house provides good insulation of the room. Unlike other types of vapor barriers, the membrane has a high price - this is its only drawback.
4. Polyethylene or polypropylene film. Compared to polyethylene, polypropylene is more durable and weather resistant. However, a vapor barrier film made of this material used to have a significant drawback - condensation formed on it from the side of the insulation, which led to a rapid loss of performance characteristics of such a vapor barrier for walls. The modern look of the material has a special layer of viscose containing cellulose. It absorbs a large amount of moisture, gradually drying under the action of air ventilation. The main advantages of films for the walls of wooden buildings are their democratic cost, strength, ease of installation.

Features of installation of vapor barrier for the walls of a wooden house

They fix the vapor barrier not only to protect the walls of the dwelling from moisture, but also to insulate the room. The material installation technology depends on the place of its application. Builders can put vapor barrier on the outside or inside of the wall, depending on the condition of the building, the type of logs, and other factors. There are certain features of the installation of vapor barriers when attaching the material from the inside or outside.

With external insulation

If the walls of the house are made of round logs, ventilation gaps may not be left: their function is performed by gaps at the junction of the bars. If the building consists of smooth wood with a rectangular or square section, it is impossible to put a vapor barrier directly on the walls - this will make it difficult for steam to escape. In this case, slats of 2.5 cm are first stuffed onto the logs (the step between them is 1 cm). After that, a crate is installed, on which thermal insulation is placed. A waterproofing film is stretched on top, and only after that you can proceed to the decoration of the walls.

If the work is done correctly, a normal microclimate is maintained in the room, which is ideal not only for log-type houses, but also for frame buildings. The described method of outdoor installation of vapor barrier for walls is simple, so that it can be done independently, without the involvement of qualified builders.

With internal insulation of a wooden house

The first stage of the internal laying of the vapor barrier involves cleaning the surface of the walls, followed by their treatment with an antiseptic. Further, according to the instructions, a lath crate is installed. A heater (for example, mineral wool) is placed in the gaps of the rails, on top of which a layer of vapor barrier is attached with nails or a stapler. If a diffusion membrane is chosen for this purpose, it is laid directly on the insulating material or leaving a gap of 5 cm between the thermal insulation and the vapor barrier. The film must be stretched well, otherwise the protective properties will be low.

Where to order and how much does wall vapor barrier cost

Material for insulation and vapor barrier of wooden walls can be purchased at hardware stores. The widest choice is presented in specialized hypermarkets. In addition, you can order a vapor barrier on the Internet, but you can see for yourself the quality of the goods only upon receipt of the purchase. How much does a vapor barrier for the walls of a wooden house cost? Below is a table with examples of prices for materials from different manufacturers.

The traditional material for building houses is wood. It has been used since ancient times. In an effort to get eco-friendly housing, modern people are increasingly paying attention to this material. But the installation process is still different. And it is precisely because of this that today it is necessary to use additional building materials. These include vapor barrier for the walls of a wooden house. We will talk about what it is and what it is used for in this article.

Why is vapor barrier needed?

In the old days, a wooden house did not need additional insulation or decoration. Its heat-insulating properties were enough to provide between the room and the street. The wood simply "breathed", and that was enough.

Today, all work is carried out in accordance with certain requirements and calculations. Therefore, in addition to environmental friendliness and attractiveness, a wooden house must also comply with energy saving standards. And this led to a change in the very concept of "house made of wood." Currently, it is most often understood as a “pie” of several layers of building materials.

Naturally, it is difficult for air to get through all these layers. Its free circulation is disturbed. Steam lingers inside this "pie". As a result, condensation forms and accumulates inside. As a result, it turns out that the insulation layer is wet.

Materials used for under the action of moisture lose their properties, deform. In addition, condensation causes the appearance of mold and fungi on the tree. As a result, the structure of the material is broken. The wood begins to "get out", the joints of the logs are broken.

The understanding of the above process necessitated the use of a protective layer. For this, a vapor barrier is used for the walls of a wooden house.

What does a frame-type wall "pie" look like?

To fully understand why a vapor barrier is used for the walls of a wooden house, it is best to understand all the layers of the “pie”. If the house is being built of a frame type, then the “pie” looks like this:

• finishing of the premises;

• frame;

• insulation;

• insulating layer (from wind, moisture);

• exterior decoration of the house.

Vapor barrier for a wooden house is also performed to protect the structure from wind and moisture.

Construction of a building from solid logs

The use of a log changes the order of fixing building materials, which is typical for frame-type buildings. In these cases, a vapor barrier is laid for the walls of a wooden house outside, and not inside.

An insulating layer is laid over the logs. Next, a frame for insulation is constructed. For this, a wooden beam is most often used. Next, a waterproofing layer is attached. On top of all this, a layer of finishing is laid. As the latter, any suitable building materials can be used. Their choice today is very large. It all depends on the preferences and financial capabilities of the building owners. For example, in this way a vapor barrier is attached to the walls of a wooden house for siding.

Types of vapor barrier

Several types of building materials can be used as a vapor barrier layer:

• Polyethylene film, which has a thickness of only one millimeter. This is the simplest and cheapest option. But it has one major drawback. The fact is that the film completely blocks the normal air circulation. As a result, the walls cannot "breathe". This type of material must be used very carefully. It breaks easily. Don't pull it too hard. Otherwise, the inevitable seasonal expansion of materials may cause damage to the film.

• Vapor barrier mastic perfectly passes air and retains moisture, preventing it from penetrating inside. It is applied immediately before finishing the room.

• Membrane film is the best option. The insulation is reliably protected from moisture, while air circulation is carried out in the prescribed volume.

The most common vapor barrier for the walls of a wooden house of the third type. It is a protective membrane. Therefore, we will dwell on its characteristics in more detail.

The best option

It is an innovative material that appeared not so long ago. Its main advantages are:

• Excellent protection against moisture penetration.

• Air passes through the membrane, which prevents the so-called greenhouse effect.

• Absolutely safe for people.

• Does not emit harmful and dangerous substances.

Even at the stage of choosing building materials, attention should be paid to the issue of membrane strength. To reduce the cost, some manufacturers reduce this figure. When used, such a membrane is easily torn. And who needs a damaged vapor barrier for the walls of a wooden house?

Which side to lay the membrane is another important nuance. It should be strictly ensured that the vapor barrier lies exactly as required by the manufacturer. If you turn it on the other side, it will not bring the desired effect.

Methods for attaching the protective layer

For the construction of a dwelling, various types of timber can be used. Depending on this, the vapor barrier for the walls of a wooden house can be attached from the outside in two ways.

The first is used in situations where the logs are round. The protective layer can be attached directly to the log.

For logs with a rectangular or square section, this option is not suitable. In such situations, a rail about two and a half centimeters wide is stuffed onto the log itself. Between them, an interval of about one meter is observed. The vapor barrier is attached to the installed rails.

Use of vapor barrier indoors

Moisture protection is provided not only outside the building. A vapor barrier is also laid for the walls of a wooden house from the inside. In this case, the whole process will look like this:

• A wooden crate is attached to the inner side of the wall. For this, bars with a width of five centimeters are used.

• Next, a layer of waterproofing is laid. In this case, a gap is formed between the wall and this film. It is necessary for ventilation of the room.

• Metal profiles are attached to the lathing bars through the waterproofing.

• A heater is placed in the cells formed between the profiles.

• From above, everything is closed with a vapor barrier membrane. She lays herself out. Joints are sealed.

• The “pie” is completed by the outer skin, which is covered with a finish.

A vapor barrier laid out in this way for the walls of a wooden house indoors will prevent condensation in the “pie”.

Things to remember during installation

It is very important to properly prepare the wooden wall before starting to fix the vapor barrier. To do this, all joints and cracks must be completely sealed.

On the outside of the building, the vapor barrier material should not be fixed tightly to the wooden wall. It is necessary to maintain openings between the vapor barrier and the finish. They are essential for air circulation. Thanks to them, the condensate from the film will go away naturally.

In the case of a frame house, the situation is exactly the opposite. Insulation does not require a rigid wall. It is attached between the bars from which the frame is assembled. As a result, two-thirds of the entire wall is insulated. Therefore, it must be carefully protected from moisture. Otherwise, the material will lose all its thermal insulation properties and other features. Deformation of the insulation will lead to the appearance of cracks.

Rules for installing a vapor barrier layer

To achieve the maximum effect from the use of a vapor barrier membrane, following some simple rules will help:

• The pattern on the membrane should be facing you, not the wall.

• Separate parts of the insulation are overlapped. They must be at least ten centimeters apart from each other.

• The material is rolled only in the horizontal direction.

• All joints are sealed. To do this, they are glued with tape, the width of which should be more than ten centimeters.

• The tape also glues elements that are complex in their design: corners, niches, ledges, window and door openings, and so on. All adjacent surfaces are glued with adhesive tape. This will improve the tightness.

• Near the windows, it is necessary to provide a margin of the membrane so that the insulation is not damaged during deformation. The stock is made in the form of folds.

• The material must be completely protected from the sun's rays. This is especially true near window openings.

• The method of fastening the vapor barrier depends on the material chosen. Polyethylene and polypropylene films are fixed with a conventional construction stapler or nails. To prevent damage to the material, it is recommended to nail it using wooden planks. With their help, the vapor barrier is pressed against the crate. From above, all this is fixed. The membrane is more stable and does not tear as easily. But it can also be fixed in a similar way.

Most Common Mistakes

The vapor barrier will not perform its functions if the installation process was performed with violations. The most common mistakes are:

• The installation was done poorly. This means poor sealing of the joints, the presence of a large number of folds, mechanical damage to the material.

• The material was chosen incorrectly. When choosing insulation, it is necessary to consider where exactly it will be attached: inside or outside. For example, suitable only for internal use.

• The effect of double vapor barrier. Occurs due to non-compliance with the installation technology. Some types of materials are attached tightly to the wall. For others, it is necessary to collect the crate.

Manufacturers of vapor barrier materials

A lot of modern companies produce films for vapor barrier. The most popular of these include the following:

• "Utah" with the trademarks "Yutafol" and "Yutavek" (Czech Republic).

• "Megaizol".

• DuPont and their Tyvek films (USA).

• "Hausrep".

• "Fakro" (Poland).

• "Dorken", producing vapor barrier under the brand name "Delta" (Germany).

• Klober (Germany).

Vapor barrier for the walls of the wooden house "Izospan" from the company Gexa is worth mentioning separately. This company produces several types. They can be used indoors or outdoors, for walls or ceilings, for a “pie” with or without insulation.

Wood is a living material, its main feature is the ability to breathe. Natural air exchange takes place in wooden houses, and the steam from the interior freely goes outside, without lingering in the wood. Today, many owners of wooden houses are trying to additionally insulate their home, turning its walls into a multilayer cake of thermal insulation, waterproofing and decorative finishes. In this case, an additional layer of such a cake should be a vapor barrier for the walls of a wooden house. From the article you will find out why it is needed, what material can be used for vapor and waterproofing of the outer walls of the log house, as well as how to attach the insulator.

Let's see if vapor barrier is needed for insulation? When the room is warm, water vapor is always formed in it, and the warmer the air, the more vapor it contains. At a certain temperature regime, which is called the "dew point", water vapor is converted to condensate. If there is a large temperature difference inside and outside the house, the “dew point” moves to the wall of the house.

When air exchange occurs naturally in the house, the steam freely leaves the room and goes outside. Now imagine that a multi-layer barrier has appeared in the way of steam. Condensate enters the heater and lingers there.

This happens every day, as a result, moisture accumulates in the heat insulator. The insulation is deformed, its heat-insulating ability decreases, moisture contributes to the formation of mold, fungi in the wood, rotting and destruction.

To avoid such unpleasant consequences, the vapor barrier, which becomes a protective barrier to the path of steam, does not allow moisture to pass into the insulation.

To increase the heat-saving parameters of log and timber houses, both external and internal thermal insulation is performed. Warming a wooden house from the outside is the most effective way, which is resorted to much more often than the inside.

Regardless of how the insulation is performed, it is necessary to choose the right vapor barrier material. If you perform thermal insulation with unsuitable material, when insulating from the inside of the house in the room, a greenhouse effect may occur, and external insulation will be ineffective. Therefore, before choosing an insulator, you need to carefully study its characteristics.

The main criteria for choosing a vapor barrier material are:

1. Water resistance, i.e. the ability of the material to withstand a certain amount of liquid, the higher this indicator, the better.
2. Vapor permeability, the maximum density of the passed water vapor.
3. Water resistance, this property is especially important for the vapor barrier of facades and wet rooms: bathrooms, baths, saunas.
4. Temperature range recommended for this material.
5. Specific gravity. This indicator is measured in g / m2, the higher it is, the stronger the material.
6. Tensile and tensile strength.

Types of materials

Materials intended for vapor barrier walls can be divided into four large groups:

• vapor barrier films.
• membranes;
• films with a foil layer;
• coating insulation.

The first group includes polyethylene and polypropylene films.

Vapor barrier made of polyethylene is usually used to save money, because, despite some advantages of PE (inexpensive price and good moisture resistance), polyethylene film has a number of significant disadvantages:

1. Low strength, the film can be damaged during installation, and it can also be deformed during operation.
2. Short service life.
3. In the interior of the house, a greenhouse effect can be created, so when using it, it is necessary to equip a forced ventilation system.

The film is destroyed under the influence of sunlight, which limits its use only to internal surfaces, it is often used for.

Polypropylene films are far superior to PE films in terms of strength and durability. The material is resistant to temperature extremes and ultraviolet. Today, films are produced from PP with a viscose and cellulose base, due to the inclusion of these materials in the composition, the absorbency of the film has increased by an order of magnitude.

Modern films used for vapor barrier walls have a multilayer structure, in which layers with vapor barrier properties alternate and a reinforced fabric that adds strength and wear resistance to the film.

Please note that when using reinforced vapor barrier films, it is necessary to leave a gap for ventilation, which contributes to the rapid evaporation of moisture.

Vapor barrier membranes

The vapor barrier breathable membrane does not interfere with air exchange and improves the ventilation of the wooden walls of the house. It is a non-woven fabric that forms a reliable protective barrier and does not allow vapors to penetrate into the insulation. There are single-sided and double-sided membranes, which respectively remove steam in one or different directions.

foil material

This group of materials has been specially developed for the vapor barrier of baths, saunas and steam rooms where conventional insulators are not suitable. On one surface of the film there is a foil, which is reflective and at the same time reduces heat loss.

Foil materials include:

• kraft paper with metallic coating;
• metallized kraft paper with lavsan coating;
• fiberglass base with foil.

Foil film can also be used for thermal insulation of the walls of residential buildings, in which, due to the use of this material, heat loss is reduced by 10-15%.

Coating insulation

For the walls of basements and basement floors of houses that are in close proximity to the ground, mastics based on liquid rubber or bitumen are used as a vapor barrier. Mastic is an aqueous polymer solution that is applied with a brush directly to the walls of the house. After complete drying of the composition, a strong film is formed on the surface, protecting the wall from moisture and steam.

How is the vapor barrier of the walls

In wooden houses, vapor barrier is usually placed from the inside of the room, and hydro and wind protection - from the front of the house. If it is planned to insulate the house from the outside under siding, lining or other finishing, the vapor barrier sheet is laid between the insulation and the wall of the house.

Wall cake with internal and external insulation is different. External thermal insulation is usually done in an old house to give it a more attractive appearance, while leaving a wooden frame. Internal thermal insulation is carried out in new buildings after external finishing work has been completed.

Basic rules for vapor barrier

1. It is very important to monitor which side of the film faces the insulation. The smooth side of the film should be on the insulation, the rough side should be on the outside. Foil films are laid with a shiny surface towards the room.
2. The vapor barrier must overlap by at least 10 cm.
3. Sealing the joints of the canvases is carried out with a double-sided tape, the width of which is at least 10 cm.
4. Near the window openings, you need to leave a margin of the canvas for the deformation of the material.

Vapor barrier of walls inside the house

When performing internal vapor barrier, in order to establish an optimal microclimate in the room and not get the opposite effect when moisture condenses inside the house, it is necessary to strictly observe the work technology.

Before starting work, it is necessary to prepare the surface of the walls, clean them from dust and dirt and carry out antiseptic treatment.

1. A wooden crate is attached to the inner walls. First, vertical racks are installed on both sides of the wall, then intermediate ones. The width of the step between the slats depends on the size of the insulation and the type of interior finish. For example, under drywall, it will be 60 m, when lining with clapboard, a distance of 40 cm is sufficient.
2. A heater is laid between the slats, it must lie very tightly to each other so that there are no gaps.
3. A vapor barrier is attached to the top of the insulation. The canvases are overlapped on top of each other, gluing the joints with double-sided tape. Then the film is fixed with a construction stapler to wooden racks.
4. Next, they make the installation of a counter-lattice for fixing the finish. The counter grille is necessary to create a ventilation gap between the casing and the insulation.
5. Perform the finishing touches.

Laying vapor barrier on external walls

With external insulation of a log house made of logs, it is possible to mount the vapor barrier directly on the logs without leaving ventilation gaps. Their function will be performed by natural voids between the logs.

It is impossible to fasten the vapor barrier directly to the walls of the house from the timber, since the circulation of steam will be disturbed.

The technology for installing vapor barrier on timber houses is as follows:

1. A frame is made of wooden slats with a minimum thickness of 25 mm, which are placed at a distance of one meter from each other.
2. Sheets of material are laid on the frame, fastening them together with a special tape. Additionally, the film is fixed to wooden racks with a construction stapler.
3. A counter-lattice is mounted on top of the vapor barrier.
4. Insulation boards are laid inside the frame.
5. A hydro-windproof film is stretched on top of the frame.
6. Decorative finishing is in progress.

Frame structures do not have a rigid base for attaching the material, so the vapor barrier laying technology is somewhat different.

The frame house should have the following structure:

1. External cladding (lining, siding, etc.)
2. Hydro and wind insulation, which is installed with an air gap in relation to the exterior finish.
3. Insulated frame.
4. Vapor barrier membrane.
5. Wooden crate.
6. Internal lining.

Such a wall cake is an ideal solution for a frame house.

The vapor barrier of the walls of the log house can be done by yourself, but with inept performance, this will lead to numerous errors and problems. The subtleties of this work are known only to professionals.

The company "Master Srubov" is ready to provide its services to residents of Moscow and the region. We guarantee high-quality and fast work on the insulation and vapor barrier of your home. To make your home always warm and cozy, contact the professional craftsmen of our company.

You can leave a request and contact us using the coordinates on the page.

In modern construction, wooden houses with single-layer walls are rarely found. The desire of the owners to make the building warmer led to the emergence of multilayer walls, in which, in addition to the wall itself and the interior decoration, there is also a layer of insulation. As a result, the design of the house began to react differently to couples who are full in the interior and who are looking for a way out. If in single-layer walls steam circulated evenly between the street and the house due to the “breathing” properties of wood, then in the wall cake it began to “get stuck” due to the different resistance of materials. And the moisture inside prevents the insulation from properly performing the function of heat saving and leads to the destruction of wooden structures. To avoid such unfortunate consequences, a vapor barrier is created - another layer in the wall cake, the task of which is to keep steam out of the insulation.

• log thickness;
• type of material processing;
• number of cracks;
• sealing quality of crowns, grooves, etc.

If the house is made of chopped logs, gun carriages or half gun carriages, then the wood in it has a natural moisture content. The walls will dry out gradually, already standing in a log house. As a rule, the box will reach the level of optimal humidity somewhere in 5 years. But the most active period is the first year. The moisture level of logs varies greatly and can lead to deformations, cracks, wall shrinkage. It is not for nothing that the first year the house is allowed to “stand up”, bringing the log house under the roof and stopping all work on this. If in the future the tree is not isolated from steam, then it will “play” for many years.

Other types of timber (rounded, glued) are already dried at the factory to the level of the required minimum moisture content, so such houses are less susceptible to shrinkage and deformation processes. Due to factory grooves and clearly calibrated dimensions, the walls turn out to be airtight and themselves become a barrier to steam, which penetrates them much more slowly. As a rule, such a house does not need a vapor barrier device.

Rounded timber due to factory drying becomes quite tight and does not need vapor barrier

When to start laying the vapor barrier layer

Option 1. We wait 5 years until the logs are completely dry, and only then we proceed to the installation of the wall cake and interior decoration. If all the cracks that appeared as a result of shrinkage are qualitatively caulked, then you can not lay a vapor barrier at all, but make a three-layer wall consisting of an outer wooden layer, a heater and an interior plasterboard finish. In this case, you will save a unique microclimate that only a wooden structure can create. But steam will enter the insulation, because both wood and drywall are permeable. With this design, it will be necessary to periodically (once every 5-6 years) open the finish and change the insulation, which will lose its thermal insulation characteristics as it becomes saturated with moisture. To prolong the life of the heat insulating layer, purchase materials that say "water-repellent treated" and "heavy density".

Option 2. If there is no time to wait so many years, there is only one way out - vapor barrier. By doing this, you will save the insulation, reduce the degree of vapor passage, but the climate of the wooden house will “suffer”, because all the properties of the tree will “hide” under the vapor barrier. But the heat saving and durability of structures will increase markedly. It is possible to create a vapor barrier layer, however, like the entire wall cake, already a year after the construction of the log house.

The vapor barrier material closes the insulation from vapors penetrating into it from the inside of the premises.

How is vapor barrier laid for external insulation of the house

Wall cake with external and internal insulation of the house is different. External insulation of houses is carried out when an old wooden house was inherited and it needs to be given a more modern look, while maintaining a wooden base. Internal insulation is usually done in new houses to leave the beauty of the logs open to the eye, or in cases where the exterior has already been finished.

Let's consider how to properly lay the vapor barrier if the insulation is done from the outside.

Since the log remains inside, then on its outer side, facing the street, the vapor barrier material will spread. For these purposes, you can choose a vapor barrier or ordinary film, roofing material, aluminum foil. Of the proposed options, the most short-lived are ordinary polyethylene and roofing material, because they have a short service life.

The roofing felt should be bituminous, having a double-sided coating, the film - more than 0.1 mm thick, the foil - more than 0.02 thick. Foil, in addition to vapor barrier, has the ability to beat off internal heat, returning it back to the rooms, so heat saving in such houses is higher than in buildings with another vapor barrier.

There must be a ventilation gap between the wood and the vapor barrier layer, which is created using wooden slats

Features of installation of vapor barrier films

If you create protection with a vapor barrier film, then when buying, carefully read what the coating is intended for. Vapor barrier is often confused with waterproofing. In our case, the film should not let steam through. Waterproofing films are permeable to steam. They create a barrier only for water. This option does not suit us, because if steam penetrates the insulation, then there is no point in creating a vapor barrier at all.

You also need to pay attention to which side to lay the vapor barrier. The manufacturer indicates this in the instructions, but if you did not find any instructions, then the principle of laying out the roll is as follows: lay on the log with the side that is adjacent in the course of rolling the roll, i.e. external.

Among waterproofing films, there is one type that can also be laid as a vapor barrier. They are called anti-condensation films. One side of such films is smooth, and the other side is fleecy due to the cellulose layer. Look carefully which side to attach the vapor barrier: the smooth side is fixed to the log, and the fleecy side will be facing the insulation. Why exactly? The smooth side creates protection for steam. But not a single film can give a 100% guarantee that steam will not seep inside, because even the manufacturer does not give this guarantee. The moisture that has got on the inside of the anti-condensation coating does not flow down, but “entangles” in the cellulose fibers, and then exits with the air flow through the ventilation gap. This property is very beneficial for a heater that will not absorb the flowing moisture from below and will remain dry.

Vapor barrier device outside the house

How vapor barrier materials are installed

Regardless of the type of the above materials, the sheets overlap. In this case, the layers should overlap each other by 2 or more cm. Self-adhesive tape is used to seal the joints, and metallized tape is used for foil.

If the house is made of a round log, then the vapor barrier layer is fixed directly on the tree, because the ventilation gap will be provided by the voids formed at the junction of the logs. If the timber with a rectangular or square section, then the surface is smooth, and air circulation will not be enough. In this case, narrow laths 2.5 cm thick are stuffed onto the logs in increments of about a meter, and a vapor barrier material is fixed on them with a stapler.

After the vapor barrier layer, a frame of timber is laid, into which insulation is laid, then waterproofing and exterior finish.

If funds allow, then you can buy a material that will be both a vapor barrier and a heater. These are foil polymers, i.e. foamed polyprofen, foam foam, etc., or fiberglass, on which foil spraying is applied on one side. Such materials are especially popular for warming baths. Remember which side to put the vapor barrier with such coatings: foil to the crate or logs, insulation to the outside.

When insulating with foil polymers, the foil should “look” inside the building

Vapor barrier device for internal insulation of the house

If the owner plans to hide the walls of a wooden house for interior decoration, then you can lay insulation from the inside. Although this option causes a lot of controversy and is considered less successful for wooden buildings than external insulation.

Consider why a vapor barrier is needed for internal insulation, and in what place of the wall cake it is created:

1. A waterproofing layer is applied along the log, which is needed to protect the walls from moisture from the outside. It must be fixed on the crate to get a ventilation gap of 3-5 cm.
2. The waterproofing is fixed with a stapler, and a metal profile frame is laid on top if it is planned to finish with drywall.
3. Insulation is laid out in between the frame.
4. A vapor barrier film is laid over the insulation.
5. Lay drywall boards.

Variants of vapor barrier and insulation of wooden walls of the house

As you can see, the vapor barrier separates the insulation and interior trim. Even if you finish the house with clapboard, and not drywall, then vapor barrier is needed, because the tree passes steam molecules well, which means it harms the insulation.

Wooden housing construction has its own specifics, so before warming the house it is better to consult with professionals. In the event of improper installation, the wall cake will quickly destroy even the most resistant wood.

The design of the walls of a wooden house always involves the creation of several layers, one of which performs the function of a vapor barrier - it prevents moisture from entering the wall from the room from destroying the insulation material.

Why you need a vapor barrier

For the walls of a wooden house, a layer of vapor barrier (also called waterproofing) is necessary in almost all cases. The reason is in the peculiarities of wood as a building material: it passes air well, but at the same time it absorbs a lot of moisture, which causes it to swell. If timely measures are not taken, this can lead to negative consequences:

• the walls will begin to curve or heave;
• the construction of the house will inevitably begin to sag due to an increase in the density of wood;
• finishing materials (lining, drywall and others), as well as wall coverings (wallpaper, MDF, PVC) may be damaged due to wall movement;
• mold can grow in the thickness of the walls, corners, which will create an unpleasant smell in the house;
• if the water freezes during the winter cold, it will increase in volume, due to which cracks and micro-slits in the wood will increase, and the material will wear out faster;
• an increase in cracks also has another negative effect - over the years, the walls will begin to freeze much faster, which is why you have to spend more resources on heating the room;
• finally, when moisture is absorbed into the insulation material, this quickly leads to its softening and deterioration - as a result, you will have to disassemble the wall and install a new layer.

All these consequences can be easily avoided if, after the completion of construction, a vapor barrier layer is laid, which follows immediately after the finishing material (for example, lining) and tightly adjoins the insulation, as shown in the diagram.

NOTE. Sometimes a vapor barrier layer is understood as a material that does not allow moisture to pass through, but allows air to pass through, and under waterproofing is a material that does not allow water or air to pass through. In a practical sense, the words are often used as two synonyms.

Is it possible to do without vapor barrier walls

Such an option is, in principle, possible if the walls of the house are made of rounded or glued laminated timber, which is carefully dried during production. In addition, all the dimensions of the grooves, where the logs will therefore lie, are calculated up to millimeters, which ensures their closest contact with each other.

But even in such cases, it is impossible to give a firm guarantee that moisture will not penetrate into the tree, since such risks remain:

• Wood as a material has its own specifics - it is porous, fibrous, serves as a nutrient medium for the development of microorganisms.
• Protective varnish treatment works well for the first 5-10 years, but over time it tends to disappear - accordingly, after this period, moisture can gradually begin to penetrate into the wood.
• Finally, if permanent residence is expected in a wooden house, it is best to take care of vapor barrier to protect its walls - the constant action of moisture coming from the kitchen, bath, from an aquarium and other household sources will make itself felt in a few years.
• To place a bath, a layer of vapor barrier is, for obvious reasons, necessary in any case.

If the house is located in a humid seaside climate, then waterproofing is an absolutely necessary measure: it is done both from the inside and outside.

Approximate calculations show that in 1 year an ordinary family of 3 people (two adults and a child) releases 150 liters of moisture into the air.

Vapor barrier materials: types, selection rules and prices

The modern industry offers many types of materials for waterproofing. Almost all of them are artificial polymers, because natural fibers always absorb moisture well and pass it in both directions.

The main indicator of the quality of such products is vapor permeability, which is defined as the amount of water (in grams) that a unit area of ​​the material (1 square meter) will miss in one day: g / m2. Normal vapor permeability does not exceed 15-20 g/m2.

From the point of view of advantages and disadvantages, the material is judged on the basis of the following consumer qualities:

• life time;
• mechanical strength;
• the ability to pass air, i.e. "breathe" while retaining moisture.

Many waterproofing materials are characterized by low air permeability, which creates a greenhouse effect in the house - you have to constantly ventilate the room, including in cold winter.

A comparison of the pros and cons of the most common materials is presented in the table (the price is in rubles for 1 roll, the total area of ​​​​which is standard 70 m2). In the case of a vapor barrier membrane, the average cost is given for a roll with dimensions of 75 per 1 meter (area 75 m2).

material	pros	minuses	price
polyethylene single layer films	affordable price, easy installation	low mechanical strength, insufficient vapor barrier	1000
reinforced (two-layer) polyethylene film	affordable price, high strength	create a greenhouse effect	1400
polypropylene film	high strength and long service life		1300
vapor barrier membranes	long service life, good vapor barrier, high strength and good ventilation properties	high price	6500
isospan (reinforced polypropylene film)	high strength and long service life, good protective qualities	the greenhouse effect	1200

If you make small holes in a polyethylene or propylene film, this will not give enough air - the walls must “breathe” the entire surface. In addition, warm air flows along with the moisture evaporated in them will penetrate these cracks. Therefore, such a vapor barrier will not give the desired effect.

Types of vapor barrier membranes

From the point of view of consumer properties, materials for waterproofing the walls of a wooden house can be divided into membranes and all the rest. The reason is that membranes are a new generation of material, different from traditional artificial polymers (polyethylene and polypropylene).

Their key advantages are as follows:

• pass moisture in an amount of not more than 10 g / m2 per day (they are especially often used in baths, saunas, pools);
• due to the porous structure, they retain condensate well, preventing it from penetrating into the insulation;
• withstand temperature fluctuations from -40 ° C to + 80 ° C;
• thanks to the reinforced structure, the fibers are able to work without wear for decades;
• the porous structure of the material ensures sufficient gas exchange between the room and the environment;
• some membranes are reinforced with foil, which reflects the heat coming from the house - thanks to this, it helps the insulation to keep the internal temperature in the room in winter.

Thus, in terms of their functions, all membranes are divided into:

They are much more expensive on the market and are mainly sold in rolls of 75 m2. Comparative prices in rubles with indication of the dimensions of the roll are presented in the table.

The main manufacturers of high-quality membrane films are German brands. High prices pay off if a major home decoration is expected, because if you make a calculation, then frequent replacement of the insulation and laying a new vapor barrier layer will become more expensive than the initial selection and installation of high-quality material.

Types of vapor barrier materials for a wooden house

Depending on the location of the material in a particular part of the house, there are:

• type A and AM - protection of insulation in the walls and roof from external influences;
• type B and C - protection of insulation in walls and roof from internal moisture;
• type D - protection of the floor from dampness emanating from the ground.

Type A

The materials of this group are intended for external insulation of the walls and ceiling (roof) of the house from the action of wind and air moisture. Installed:

• under the external decoration of the wall for insulation;
• under the roof of the roof;
• into ventilation shafts.

In order for the membrane to work correctly, passing moisture from the inside and blocking it from the outside, you need to carefully lay the layers - with the marked side (with the inscription of the brand and manufacturer), it must “look” towards the street.

The material is installed on a counter-lattice so that excess moisture can drain. On the roof, it is important to create an appropriate angle (at least 30-35o).

Type AM

At the place of laying, this material is mounted in the same way as type A. It has a more complex multilayer structure:

• spunbond layers (1-2);
• diffuse film.

It is thanks to the diffuse film that steam escapes from the inside, but the liquid does not pass from the outside. An important feature of this material is that it does not need a ventilation gap, therefore it is mounted close to the surface of the insulation.

A spunbond is understood as a special technology for the production of a polymeric moisture-proof film, as well as the product of this production itself. In this case, the fiber consists of artificial threads that are sewn together under the action of chemicals, heat or water jets.

The result is a very strong porous fiber that allows air and moisture to pass through well, but at the same time reliably protects not only from precipitation, but also from the effects of wind. All these valuable properties are explained by the peculiarities of the structure of the multilayer material.

Type B

Such a vapor barrier is used to protect the walls of a wooden house from internal moisture. It is also used for finishing the roof from the inside, especially in cases where it is planned to create a living space in the attic with the possibility of year-round use (like an attic).

And another use case is the internal insulation of the floor, as well as the interfloor ceiling.

Multilayer materials additionally protect against wind, and foil materials retain heat inside due to its reflection from its surface.

Type C

Represents especially strong membrane consisting of 2 layers. It is used in the same cases as B. It is also used for insulation in unheated rooms adjacent directly to the house:

• attics;
• cellars;
• plinths;
• verandas, canopies.

Such materials are made of polypropylene and are reinforced with an additional laminating layer, due to which they are used in floor and roof insulation - i.e. in cases where a strong mechanical load is expected (pressure of furniture, movement and wind action).

Ways to fix the vapor barrier film

Materials are fixed using two methods:

• construction stapler;
• special tape (adhesive tape).

Often both methods are combined together. At the same time, the adhesive tapes themselves are made from approximately the same materials as the vapor barrier. They are reinforced using spunbond technology, as it is assumed that they will be subjected to a constant load. There are several types of adhesive tapes that correspond to the types of waterproofing membranes considered:

Do-it-yourself vapor barrier laying: step by step instructions

The technology of laying a layer with vapor barrier in the walls of a wooden house depends on its design:

• frame house;
• timber house.

In addition, there are features of laying the material indoors and outdoors. Since in the latter case it makes sense to protect the house from blowing cold winds, a layer is almost always installed to protect against them. And waterproofing is installed in cases where the house is old enough, and the walls need to be protected from the damaging effects of moisture.

Vapor barrier from the inside

When laying a layer with waterproofing inside the walls, it must be taken into account that water, evaporating on the surface of the material, must drain somewhere. Thus, the layer should not be in too close contact with the insulation - a small gap is needed.

The sequence of actions is as follows:

• If the house is built from a cylindrical beam, then due to the natural rounding, it creates a sufficient gap for moisture removal - in this case, the membrane is attached directly to the logs using a stapler.
• This is followed by a crate and internal finishing material (lining, drywall, etc.).
• In the case of houses made of rectangular timber, as well as when installing insulation (in cold winter conditions), the membrane is attached to a counter-lattice, which is mounted to the main timber through small wooden beams of the same size. They are located at a certain interval and hold the insulation, on top of which the vapor barrier is placed. The same technology is assumed for a frame wooden house.

Visually, the method of installing an internal vapor barrier can be seen here.

Possible errors that are important to consider immediately when laying the layer are presented in the video.

NOTE. Layers of material are overlapped by at least 15-20 cm and securely fastened with joints.

Vapor barrier outside

In this case, the film or membrane should lie immediately under the sheathing layer (for example, siding) and tightly adjoin the insulation.

Space for the accumulation and natural discharge of condensate must also be present.

The technology is as follows:

Features of the technology are shown in the video.

The outer vapor barrier membrane must be well ventilated. The use of polyethylene, polypropylene and other films in this case is unacceptable, since the moisture leaving the house will stumble upon the barrier and will not be able to go outside - it will settle on the walls and insulation, due to which they will begin to rot.

Vapor barrier and heaters: what is the ratio

Since the vapor barrier of walls in a wooden house is carried out mainly to protect the insulation, you should figure out in which cases this is of particular necessity, and in which it is enough to simply cover the walls, for example, with plastic wrap. In this sense, there are 2 options:

• If foam plastic, polyurethane foam and similar materials are used as insulation, then a film or membrane is not needed directly to protect them, since they do not absorb moisture.
• If the house is insulated with mineral or ecowool, as well as sawdust, the membrane is extremely necessary - damp cotton wool will turn into dust in just 1-2 years.

If the house is old and made of a wooden frame or a bulk structure, a layer to retain moisture will be needed in any case to protect the wood itself.

By correctly choosing and installing a vapor barrier layer, you can not only improve the microclimate in the house, but also significantly extend the life of the insulation and wood.