Proper installation of vapor barrier walls from the inside of a private wooden house. Installation of wall vapor barrier Vapor barrier for external walls of a wooden house

Vapor barrier is one of the most important stages in the construction of a wooden house. It protects building materials from exposure to steam, deformation, as well as the occurrence of fungus and mold.

Vapor barrier: necessary or not

A steam protection device is required if:

If the base is insulated from the inside with mineral wool. This is due to the fact that moisture adversely affects the properties of this insulation. For this inside the building.
Frame houses, the walls of which consist of more than one layer.
If the brick walls are insulated from the outside with mineral wool and. In this case, the vapor barrier will perform a windproof function that protects the walls of the house from strong blowing. From the made windproof layer, the ventilation gap removes excess moisture.
For external walls located in close proximity to the foundation, where condensate forms most actively.
Walls made of logs or timber of natural moisture. Drying of such timber is carried out, being directly in the clearing, and the tree reaches the optimal moisture content only not earlier than after 5 years. The maximum degree of moisture content changes during the first year, so the bars are erected under the roof and left to dry for at least a year.

From which the walls of the house are erected, it is dried to low humidity even at the stage of its production, it has sealing recesses, slight dimensional fluctuations, as well as slight shrinkage.

The material is impermeable and provides optimal restriction of steam penetration into the thermal insulation layer.

Therefore, walls erected from timber are a good vapor barrier. Often they do not need an additional protection device.

Laying a vapor barrier for a wooden house can be carried out one year after its construction. This saves thermal insulation and reduces the level of vapor transmission.

It is not recommended to mount a vapor barrier on both sides, this prevents the wood from drying out naturally.

Vapor barrier of walls outside

Steam insulation can be done in several ways, depending on the type of log used:

When building the walls of a house from a round log, the insulation layer is attached directly to the tree using a construction stapler. Ventilation gaps in this case are not required, it will be provided by the voids formed at the junction of the bars.
If the beam has a rectangular or square section, the surface is smooth and the air movement is not enough. Then planks 2.5 cm thick are stuffed onto the logs with a step between them of 1 meter. A vapor barrier material is laid on the completed crate and fixed with a stapler.

The following materials can be used to provide vapor barrier:

Plain polyethylene film. It should be noted that this material is not very effective, its main drawback is the formation of a greenhouse effect, it does not allow moisture or air to pass through. Some experts advise to perforate the film with your own hands, that is, to make many small holes on the roller, on which the nails are planted. However, this option is not feasible, the formed pores conduct moisture in two directions, and, accordingly, it will not be possible to provide membrane insulation from steam. The cost of the film depends on the manufacturer and ranges from 500 to 1100 hryvnia.
membrane films. Such material is able to pass air, while retaining moisture. There are three types of membranes: diffusion, superdiffusion and three-layer. The films are made according to a two-layer principle, one of which provides protection from steam from the outside, the second one - promotes the penetration of steam from the insulation to penetrate inside the house. The quality of the film depends on the vapor permeability index, the higher it is, the better. The price of membranes fluctuates on average from 750 to 4500 rubles per roll.
Mastic. The material is intended for application to the base prior to facing works. The cost varies from 32 to 92 rubles per 1 liter.

Consider how to properly lay the vapor barrier on the outside of the walls of the house.

Laying vapor barrier directly on the outer surface of a wooden wall is not recommended.

The wood base, compared to a brick or concrete wall, has a strong thermal resistance, which can be compared to the heat transfer resistance of a thermal insulation layer.

The redistribution of temperature and moisture content in the insulated base layer can be such that on the inside of the film the temperature will be lower than the temperature required to cool the air so that the vapor begins to condense into dew. This contributes to the formation of condensation on the inside of the insulator and moistening the wall.

As a result, a ventilation gap of up to 5 cm is needed along the line of the base and the film, due to which the temperature in the room is set equal to the temperature of the room, that is, exceeding the dew point.

To remove the formed moisture, it is necessary to equip special channels near the foundation and the eaves of the house.

Vapor barrier of walls from the inside of a wooden house

The vapor permeability of a wooden base largely depends on the impermeability of the sealing of joints, grooves, and the absence of cracks in the wood.

Therefore, the walls of a wooden house often require auxiliary protection.- devices of a vapor barrier layer during their insulation.

Vapor barrier can be performed on the inner surface of the tree, but such a solution would not be entirely correct. The best option- the device of the crate, which in the future will serve as a frame for the interior cladding.

To do this, wooden planks are stuffed on the surface of the base in a vertical direction, which are set according to the level (wedges are stuffed along the depressions, and the material is removed on the ledges). First, the extreme rails are set, along which the intermediate strips are aligned by means of a thread.

The insulating material is stretched onto the crate from the bottom up and fixed with a construction stapler.

Lay the insulation in such a way that the matte rough side is directed inward, this reduces the formation of condensate. It is not necessary to stretch the film very much, because after a while the wood will dry out, the tension may increase and the vapor barrier will simply break.

The sheets are overlapped and glued with moisture-proof adhesive tape.

A fabric with a self-adhesive strip along the edge will help speed up the process, thanks to which the joints are securely glued without additional time spent on their subsequent gluing.

For the device vapor barrier indoors, the following materials are used:

polyethylene film, the thickness of which is more than 0.1 mm;
membrane film;
mastic (great for a drywall base, the material is breathable while retaining moisture);
aluminum foil, at least 1.02 mm thick.

The foil is laid with a reflective surface towards the air space, this ensures a decrease in the degree of heat transfer.

Estimated cost of the material (depending on the manufacturer), the price is for 1 roll:

aluminum foil - 800–6300 rubles;
connecting tape - 150-500 rubles.

For an effective vapor barrier device, certain rules must be followed:

Inside the house, vapor barrier materials are mounted on walls that divide the living space into zones. These zones are often insulated with mineral wool, which, by accumulating moisture, loses its positive properties. Therefore, it is recommended to lay a vapor barrier on top of the insulation.
On the inside of the base, the film is best fixed with wooden planks, pre-treated with an antiseptic. Lay it on both sides of the partition walls. At the junction, an overlay of sheets of approximately 2.5–3 cm should form, while the edges on both sides should not coincide with each other, and the distance between them should exceed half a meter.
For effective ventilation of the walls and an optimal environment, the insulation is mounted on the inside of the heat-insulating layer.

Materials that prevent the penetration of steam, often confused with waterproofing materials, so when buying, you should pay attention to what purposes they are intended for.
To ensure high-quality insulation from the steam of the walls from the inside, it is necessary to maintain a distance from the film to the finish of at least 3 cm. This contributes to the free circulation of air and the removal of moisture formed on the membrane.
The vapor barrier material reduces the ventilation of the walls to zero, therefore, it is necessary to install auxiliary ventilation, such as valves on windows, fans in walls and vents.
Due to the fact that certain internal linings have their own vapor barrier, the layers in the thickness of the wall should be placed in such a way that the vapor barrier properties increase from the inside to the outside.
During laying, the material must adhere tightly to the thermal insulation material., firmly attached to the component parts of the mounting system. Loose sections and sagging should also not be.
Steam insulation should form a solid contour with the basement and attic floors.
Before performing the vapor barrier layer, it is necessary to check the surface of the base for the presence of seams, cracks and seal it with a sealant.

When building a house, one of the main tasks is to ensure reliable protection of the building from interaction with water, which has a destructive effect on any building material. Other factors that adversely affect materials are steam and moisture. If you do not think about how to protect structural elements from them, then such frivolity can lead to the appearance of fungus and mold. To avoid this, during the construction of houses, a layer of vapor barrier is laid.

Why is vapor barrier needed?

Currently, many people who build individual residential buildings are thinking about installing a vapor barrier. Vapor barrier is especially relevant in those houses in which warm microclimate prevails and the humidity level is quite high. This applies primarily to baths and basements located below ground level.

During their operation, steam is constantly generated in them, which must somehow leave the room. Therefore, it settles on the walls and ceiling. With prolonged exposure to steam on these surfaces, building structures are destroyed, which negatively affects the state of the structure as a whole. To prevent this from happening, install a vapor barrier. With her help Provides protection for walls and ceilings from steam penetration.

It should be noted that in addition to baths and basements, vapor barrier of surfaces in the interior should also be carried out in the case when the building has external insulation with a material with low diffusion resistance.

At the moment, there is no material that would be equally good for buildings made of different materials. When deciding which vapor barrier to choose for the walls of the house, they start mainly from the elements that make up the structure of the wall structure.

When is it necessary to install a vapor barrier on the walls?

In some cases, it is simply impossible to do without a vapor barrier device, the installation of which should be carried out correctly:

Materials used for vapor barrier

The term "vapor barrier" should not be taken as a barrier that does not allow steam to pass through. Membrane materials, currently used in steam protection work, provide the passage of air in a minimum amount, which completely eliminates the possibility of a greenhouse effect. Excess moisture is retained in the membrane, and the air freed from moisture is not able to harm the wall structure or reduce the performance of the insulator. Vapor protection materials have an internal “coat” that ensures that moist air is redirected along the desired path through the ventilation system.

Types of vapor barrier materials:

polyethylene is a material traditionally used for vapor barrier of house walls. When performing installation work with its use, it should be handled with particular care. The insulator must be fastened so that it is not too tight, otherwise the film will simply tear at the next change in climatic conditions. If polyethylene without perforation is used during vapor barrier work on the walls of the house, then it will become a reliable protection not only from steam, but also from air. And in this case, there can be no talk of comfortable living conditions in a dwelling. Therefore, it is best not to use such material to create a vapor barrier layer;
the group of vapor barrier materials includes mastics that have been developed specifically for this purpose. Using them during work from inside the building, the material will retain moisture and let air through. Note that the work on applying mastic on the surfaces of walls and ceilings is performed before their finishing;
new material for vapor barrier are membrane films. Their appearance on the market happened some time ago. In a short period, this material has become in demand and is currently actively used in vapor barrier works on the walls of wooden houses. The main advantage of these materials is that they allow air to pass through and retain moisture. The vapor permeability that is characteristic of them is relative. This allows you to ensure the normal operation of the heat insulator. The use of membrane materials to protect the walls prevents the cotton wool from getting wet. It does not lose its integrity and can perform its functions for a long time.

Common brands of membrane materials

At the moment, vapor barrier materials are presented in a wide range. And each of them is designed for a specific area of \u200b\u200buse.

Vapor barrier materials installed outside

This group of materials includes "Izospan A", "Izospan B". One of their features is that the materials contain flame retardant additives, which increases their fire safety. This also includes "Megaizol A", "Megaizol SD". All of these materials are used to protect timber structures, as well as houses built using frame technology, and panel buildings. These insulators provide protection against precipitation, snow and wind. They are used for all types of external insulation.

When using them, it is essential to ensure tight seal of the membrane to the heater. Therefore, during work, these materials should be securely fixed. Sagging and loose areas should be absent. Otherwise, with strong winds, rare gusts will occur.

Indoor installation materials

When the task is to perform vapor barrier of walls, ceiling from inside a wooden house, then Megaizol V is used. It is a polypropylene film, which consists of two layers. On the outer side of this material there is an anti-condensation surface. The use of this material in winter ensures its protection against phenomena such as condensation and fungus. In addition, its use eliminates the destruction of elements of wall structures. Also, this material provides protection of the room from the ingress of particles of insulation. The same function is inherent in Izospan B.

Materials for hydro and vapor barrier with a reflective layer

This group includes the following materials: IzospanFD, IzospanFS, IzospanFX. They are used in cases where it is necessary to arrange a vapor barrier in rooms in which special requirements are imposed on this procedure. For example, it can be saunas or baths.

Rules for vapor barrier of frame walls

In frame-type houses, high-quality insulation is more important than in brick buildings or houses made of timber. The comfort of living depends on this in many respects. Therefore, special attention should be paid to vapor barrier. To protect the insulation from steam on the walls, the membrane must be fixed on the correct side. Should be attached to racks. with a stapler. The membranes formed after laying on the walls must be insulated with a special adhesive tape. Or you can use special mastics to seal them.

If ecowool or polystyrene is used in frame buildings as a heater, and an effective ventilation system is installed in the house itself, then a vapor barrier device can be abandoned. If the owner of the building has decided to provide protection from steam, then in this case you can use one of the following schemes:

the first scheme involves sewing the membrane onto the elements of the wall frame rack. After laying the film, surface finishing work is carried out. Drywall or lining can be used as a material. This option is optimal for wooden houses, which are used by the owners for temporary residence, and are empty in winter. It can be used in guest houses and workshops. Using such a vapor barrier scheme for the walls of the house, it is necessary to arrange an effective ventilation system.
the second scheme involves the device on top of the laid vapor barrier membrane of the crate, which is located in a vertical and horizontal position. Thanks to it, an air gap of 30-50 mm is provided. It is best to use this design in houses that are used for permanent residence. In this case, increased humidity occurs in the premises of a wooden house and the structures need effective protection from steam.

Vapor barrier of the walls of a wooden house

The walls of a wooden house should have a higher vapor barrier compared to brick buildings. When choosing membrane materials for insulating surfaces in wooden structures, one should proceed from the thickness of the beam, tightness of the grooves, the presence of cracks in the material of the walls.

A popular material for the construction of wooden houses is glued beams. In the process of its manufacture, the wood is dried in special chambers. The result is a low level of moisture in the finished material. It has grooves for sealing. The material is characterized by low shrinkage, so it enters the insulation in a limited amount.

When a wooden house is built from a bar with a natural level of humidity, the drying process of the material occurs during the operation of the building. During the first five years in such a house, cracks appear on the material. At the bar, the geometric dimensions change, the tightness of the grooves is broken. Therefore, work on finishing the house during the shrinkage period cannot be carried out. Otherwise, upon its completion, it will be impossible to restore the tightness of the grooves. In the case of such buildings two options are possible:

wait for the wood to dry;
perform a vapor barrier of the walls of the building, using membrane films "Izospan B", "Izospan FB" or "Izospan FS" during work.

Conclusion

Now everyone understands that vapor barrier is important in every home. All work must be carried out correctly, i.e. according to technology. During the work, modern high quality materials should be used. If you want to live in your home in comfortable conditions, then vapor barrier should become a mandatory procedure for you. It will provide steam protection. The house will be reliably protected from moisture and will last a long time.

The advantages of a wooden house include a unique microclimate. This is due to the ability of wood to absorb excess moisture and give it away when the air in the room is too dry. Also, through the wooden walls there is a constant air exchange - it is easy to breathe in the house.

If the house is built of dry logs or glued laminated timber, and the thickness of the walls is sufficient to keep the heat inside the building, then it does not need additional thermal insulation. In the case when the construction was carried out from lumber of natural moisture, or with insufficient wall thickness, it is necessary to install external or internal insulation.

In order not to nullify the advantages of a wooden house and not provoke wood decay, you should carefully consider the choice of heat-insulating material. It must pass air, so it is recommended to opt for mineral (basalt) wool, which is not subject to biological destruction.

Due to the fibrous structure, mineral wool is able to absorb moisture. This causes:

a sharp decrease in the thermal insulation properties of the material, freezing;
deformation of the insulation (when wet, it is crushed and slides down);
rotting of wooden walls in contact with a moistened heat insulator;
dampness and damage to interior finishes.

To prevent moisture from entering the insulation, it is required to protect it with a special film barrier with the appropriate properties. Consider what should be the vapor barrier for the walls of a wooden house.

Vapor barrier materials

Depending on the selected insulation option, the vapor barrier is mounted outside the house or inside the building. It is important to choose a material with optimal performance so that the house is warm and comfortable, the heat-insulating cake lasts a long time, and the wooden walls are not damaged by fungus.

A wooden house does not need absolute isolation from steam passing through the insulation and walls during natural air exchange. The use of sealed materials for internal insulation will lead to a "greenhouse effect" in the room.

We will determine which vapor barrier material is better to choose. Three types of vapor barriers are used in construction:

polyethylene film;
mastic;
membrane film.

The plastic film does not allow air to pass through, so its use inside the house is contraindicated - even with good ventilation in the room it will be uncomfortable. Polyethylene contributes to the settling of condensate, which can lead to damage to the wall finish.

A popular advice is to perforate plastic wrap with a spiked roller to allow air to pass through. But together with air, such a barrier will also allow water vapor to pass through, that is, it will not be able to perform its function. For external insulation, polyethylene film is also not very suitable, since the material loses its strength under the influence of high and low temperatures.

Mastic, capable of passing air, but retaining steam, is not suitable for wooden walls. This material is applied directly to building structures, and we need to protect the insulation from steam.

Vapor barrier membranes are characterized by a multilayer structure and the ability to retain excess moisture, allowing air to pass through. Membrane materials are suitable for internal insulation and can be used as part of an external heat-insulating "pie".

Features of vapor barrier membranes

The membrane material is breathable and, to a certain extent, vapor permeable. This allows for normal gas exchange through the walls, taking advantage of the advantages of a wooden house. At the same time, the fibrous insulation inside the room will be protected from excess moisture, the removal of which will require high-quality ventilation. With external insulation, excess moisture leaves through the ventilation gaps.

When designing an insulation system, it is required to select the appropriate vapor barrier material. Membranes differ in the degree of air and vapor permeability, in structure.

The inner side of the membrane may be rough due to the inclusion of fibrous material. This side should be turned to the insulation - in this case, the excess moisture that has penetrated the barrier will remain on the surface of the membrane, and will not enter the heat insulator. Membranes with an anti-condensation surface are intended for use as part of the internal insulation of wooden walls.

Outside, the membrane can be foil-coated - the metallized layer reflects thermal radiation, which contributes to heat saving. A vapor barrier with a foil side is recommended for use in the arrangement of wooden baths and saunas.

The material for creating a vapor barrier is selected taking into account the operational features of the heat-insulating "pie".

Sectional wall cake of a wooden house

Popular on the Russian market are:

"Megaizol A", "Megaizol SD", "Izospan A" (including those with flame retardant additives) - for the installation of an external thermal insulation system of a wooden house;
"Megaizol V", "Izospan V" - for internal insulation of residential and utility rooms;
"Izospan" FD, FS, FX - for rooms with increased requirements for thermal insulation efficiency (baths, saunas, etc.).

Indoor installation

When protection is needed for the insulation inside the house, the membrane material is fixed over the crate, between the elements of which mineral wool insulation boards are inserted. Pay attention to the manufacturer's instructions to secure the membrane with the correct side facing in.

The canvases are overlapped (at least 2 cm), carefully glue the joints with aluminum tape. To securely attach the membrane to the crate, use a construction stapler with staples. The film should not sag, have gaps and gaps. Particular attention is paid to fixing the material around the perimeter to minimize the possibility of moisture penetrating under the membrane.

Installation outside the house

When the insulation is installed outside the house, a vapor barrier separates the heat insulator from the wooden wall. On flat (timbered) walls, in order for the moisture that the wood will let through to go away, you need a crate of slats 25 mm thick. It is stuffed in increments of 80-100 cm and a membrane or other material is attached on top to prevent the penetration of steam into the insulation.

Insulation of the walls of a wooden house from the outside

A vapor barrier is attached to a log wall without additional lathing - the cavities between the logs serve as ventilation ducts. The film outside the building must be mounted without sagging. To determine which side to turn the membrane to the insulation, follow the manufacturer's instructions.

A crate is attached over the vapor barrier, in the cells of which mineral wool is laid. Then you need waterproofing, on top of which external finishing is performed.

Please note: as a vapor barrier when warming the house from the outside, it is allowed to use waterproofing materials that do not allow steam to pass through - roofing material, polyethylene, foil. When choosing which material to use, cost and durability are taken into account.

When is the insulation of a wooden house required?

Installation of an external or internal insulation system is needed if the house is built from unseasoned wood. In this case, shrinkage occurs over several years and is accompanied by the appearance of gaps between the log units. Additional thermal insulation is also required for old houses or with insufficient wall thickness.

When choosing which insulation option to prefer, please note that during the internal installation of a heat insulator, increased requirements are imposed on the vapor barrier - it must pass air. It is important to mount the multilayer membrane with the correct side.

If you have any doubts about the choice of vapor barrier materials for the walls of your house, you can always contact the experienced specialists of the Marisrub company, who will provide professional advice and carry out work on exterior or interior decoration.

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 construction is completed, 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 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	create a greenhouse effect	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	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 into 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 an 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 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 too tightly in 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 the walls in a wooden house is carried out mainly to protect the insulation, it is necessary to 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.

The most important step in the insulation of any building is the vapor barrier of the walls. Why is it needed, what functions does it perform, and why is it impossible to do without it in most cases? An amazing fact: in the course of normal life, a family of three releases about 150 liters of water into the environment in the form of water vapor. This volume is enough for a large, good bay of neighbors! Meanwhile, all this moisture does not go down, but rises up and to the sides and tries to naturally exit the room through the walls and ceiling.

Wood is a very porous material that is well breathable and absorbs moisture. Imagine that now "overboard" is about -15 °. The house is warm. You breathe, cook borscht for dinner, do laundry, take a hot bath in the evening. All this leads to the formation of water vapor. Moisture is absorbed into the walls and tries to get out. Somewhere in the thickness of the wall - closer to the outer or inner surface (this depends on the thickness of the walls and the quality of the insulation) - there is a "dew point": the boundary at which water vapor turns into water.

This water freezes (it's cold outside!), as a result of which several very undesirable processes take place at once:

Dampness of the wall and / or insulation.
Freezing of the walls due to the transformation into ice of moisture that got inside.
Gradual destruction of the wall structure.
The appearance of fungus and mold.

All this helps to avoid the vapor barrier of the walls of a wooden house.

Under extreme weather conditions, some water may get under the cover. Therefore, during the construction of the house, ventilation gaps are made and a vapor barrier film is installed.

The device of external and internal vapor barrier

In our climatic conditions, the insulation of the walls of houses is a necessity: in order to ensure a comfortable temperature in the premises in winter, without spending astronomical amounts on heating, one has to use the benefits of civilization in the form of insulation materials. In order for them to work efficiently, it is necessary to vapor barrier the walls of a wooden house from the outside or from the inside - it depends on where the insulation is located. If moisture gets into the heat-insulating layer, it will significantly increase its thermal conductivity, which means heat loss, reduce the life of the insulation - vapor barrier allows you to avoid this.

Vapor barrier films are made by weaving. Consist of a polypropylene base coated with laminite on one or both sides

How is the insulation of wooden walls outside

Insulated walls - multi-layer construction. Its foundation is the walls of the house. A crate of wooden bars is attached to them, between which insulation plates are laid - stone, basalt wool. Then a vapor barrier film is attached on top of them, which is pressed against the crate with slats. Facing material is mounted on them - lining, siding, etc. As a result, an air gap is formed between the vapor barrier and the cladding. It is necessary so that moisture, condensing on the vapor barrier, gradually evaporates without getting inside the structure and without moistening the cladding.

Another version of the same design provides for an additional layer of wind and waterproofing, which is located immediately on the wall of the house, between it and the insulation. This prevents the insulation from getting wet vapors into the insulation from inside the house.

Scheme of the vapor barrier device and insulation of the house from the outside

Wall insulation from the inside

In this case, the work is done in a similar way. Material layers are arranged in the following order:

Wall of the house.
Frame bars, between which insulation boards are laid.
Vapor barrier membrane pressed against the frame with slats.
Wall cladding - drywall, lining, which are attached to the rails.

The sheets are attached to each other with a stapler, then the vapor barrier is fixed with pre-antiseptic slats 4x5 cm

Vapor barrier of the walls of a frame house

Frame houses are distinguished by the fact that they do not have a rigid base for insulation - walls. It is located between the racks of the timber frame. In such houses, the cross section of the walls is as follows:

Exterior cladding (OSB boards, siding, lining, block house).
Hydro-wind protection - a membrane that protects the insulation from moisture from the outside. Between it and the outer cladding, a ventilation gap is required, due to which the moisture that has fallen on the membrane gradually evaporates from the surface due to natural ventilation.
The frame of the house with a heater embedded in it.
Vapor barrier membrane. It is necessary to install the vapor barrier of the walls with the rough side of the film from the insulation.
Crate.
Interior wall decoration.

Since 70% of the volume of frame walls is occupied by insulation, its protection from moisture is very important. Otherwise, it loses its properties, crumples and moves away from the frame, cracks appear, and the house freezes.

When building frame houses, the use of wind protection and vapor barrier is mandatory.

Features of laying vapor barrier on walls

Manufacturers offer different types of vapor barrier materials. The most modern and high-tech of them are vapor barrier membranes. They are made from polypropylene, based on a fiberglass mesh, which gives the material strength. One or both sides of the film have a special coating that is rough to the touch. This is a layer of cellulose-viscose fibers that absorb moisture well. When it hits the surface of the membrane, it lingers in the rough layer, without passing further and without getting into the insulation and the thickness of the walls. This moisture is then evaporated by natural ventilation. Vapor barrier materials are also produced with a metallized coating on one side. It serves to reflect heat energy into the room, thereby reducing heat loss.

Important: the foil surface should be facing away from the insulation, towards the room.

Foil vapor barrier not only retains moisture, but also retains heat

The installation of the vapor barrier membrane on the wall is carried out in horizontal strips, starting from the floor. At the joints of the strips, it is necessary to overlap each other by at least 10 cm. The joints are glued with a special connecting tape, which gives a tight connection. The places where the film adjoins wooden or stone surfaces must also be carefully glued, achieving complete tightness. The membranes are fastened to a wooden frame using a construction stapler or galvanized nails.

Laying vapor barrier on the walls in a wooden house

Of course, do-it-yourself vapor barrier of walls is quite feasible. True, it is quite difficult for a non-specialist to perform the whole range of work on wall insulation: mistakes when using high-tech modern materials are fraught with serious troubles. So that the new house does not require urgent repairs, it is much more reliable to turn to the services of professional builders.