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The most important stage in the insulation of any structure 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 allocates environment about 150 liters of water in the form of steam. This volume is enough for a large, nice bay of neighbors! Meanwhile, all this moisture does not go down, but rises up and to the sides and tries to naturally leave the room through the walls and ceiling.

Wood is a very porous material that allows air to pass through and absorbs moisture. Imagine that it is now about -15° “overboard”. The house is warm. You breathe, cook borscht for lunch, do laundry, take food in the evening hot bath. All this leads to the formation of water vapor. Moisture is absorbed into the walls and tries to come 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 occur at once:

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

Vapor barrier of walls helps to avoid all this wooden house.

In extreme weather conditions, some water may get under the cover. Therefore, when building a house, ventilation gaps are made and a vapor barrier film is installed.

Installation of external and internal vapor barrier

In our climatic conditions, insulating the walls of houses is a necessity: to ensure comfortable temperature indoors in winter, without spending astronomical amounts on heating, you have to enjoy the benefits of civilization in the form 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 and reduce the service life of the insulation - vapor barrier allows you to avoid this.

Vapor barrier films are made using the weaving method. Consists of a polypropylene base coated with laminite on one or both sides

How to insulate wooden walls from the outside

Insulated walls are a multi-layer structure. Its base is the walls of the house. A sheathing of wooden blocks is attached to them, between which insulation slabs are laid - stone, basalt wool. Then a vapor barrier film is attached over them, which is pressed against the sheathing with slats. Mounted on them facing material– 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 lining.

Another version of the same design provides an additional layer of wind-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 vapor barrier device and insulation of the house from the outside

Vapor barrier of walls from the inside

In this case, the work is carried out in a similar way. The layers of materials are arranged in the following order:

• House wall.
• Frame bars, between which insulation boards are laid.
• Vapor barrier membrane, pressed to the frame by slats.
• Wall cladding - plasterboard, lining, which are attached to slats.

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

Vapor barrier of frame house walls

Frame houses They differ in that they do not have a rigid base for insulation - a wall. It is located between the racks of the timber frame. In such houses, the cross-section of the walls looks like this:

• External cladding (OSB boards, siding, lining, block house).
• Hydro-wind protection is a membrane that protects the insulation from moisture from the outside. Between her and external cladding absolutely necessary ventilation gap, due to which moisture trapped on the membrane gradually evaporates from the surface due to natural ventilation.
• The frame of a house with insulation embedded in it.
• Vapor barrier membrane. It is necessary to install vapor barriers on walls using the rough side of the insulation film.
• Lathing.
• Interior wall decoration.

Since 70% of the volume frame walls takes up 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.

During construction frame houses It is mandatory to use wind protection and vapor barriers

Features of laying vapor barrier on walls

Manufacturers offer different types vapor barrier materials. The most modern and high-tech of them are vapor barrier membranes. They are made from polypropylene, with a fiberglass mesh base that 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 gets on 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 through natural ventilation. Vapor barrier materials with a metallized coating on one side are also produced. It serves to reflect thermal 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

Installation of the vapor barrier membrane on the wall is done in horizontal stripes, starting from the floor. At the joints of the strips, it is necessary to overlap them with each other by at least 10 cm. The joints are glued with a special connecting tape, which provides a tight connection. The junctions of the film with wooden or stone surfaces must also be carefully glued, achieving complete tightness. The membranes are attached to the wooden frame using construction stapler or galvanized nails.

Laying vapor barrier on walls in a wooden house

Of course, vapor barrier of walls with your own hands is quite feasible. True, it is quite difficult for a non-specialist to complete the entire range of work on wall insulation: mistakes when using high-tech modern materials are fraught with serious trouble. To new house did not require urgent repairs, it is much safer to turn to the services of professional builders.

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

Why is vapor barrier necessary?

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 characteristics of wood as building material: it allows air to pass through well, but at the same time absorbs a lot of moisture, which causes it to swell. If timely measures are not taken, this can lead to negative consequences:

• walls will begin to curve or heave;
• the structure of the house will inevitably begin to sag due to increased wood density;
• finishing materials (lining, drywall and others), as well as wall coverings (wallpaper, MDF, PVC) can be damaged due to wall movement;
• mold may grow in thick walls and corners, which will create bad smell in the house;
• if the water freezes during winter cold, it will increase in volume, due to which cracks and microcracks 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 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 - eventually you will have to dismantle the wall and install a new layer.

All these consequences can be easily avoided if, after completion of construction, a vapor barrier layer is laid, which follows immediately after the finishing material (for example, lining) and is tightly adjacent to 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 waterproofing is a material that does not allow either 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?

This option is, in principle, possible if the walls of the house are made of rounded or laminated veneer lumber, which is thoroughly dried during production. In addition, all the dimensions of the grooves where the logs will fall are calculated to the nearest millimeters, which ensures their tightest contact with each other.

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

• Wood as a material has its own specifics - it is porous, fibrous, and serves as a breeding ground for the development of microorganisms.
• Protective varnish treatment works well during 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 it is assumed permanent residence in a wooden house, it is best to take care of a vapor barrier to protect its walls - the constant action of moisture coming from the kitchen, bath, aquarium and other household sources will make itself felt over several years.
• To house a bathhouse, a layer of vapor barrier is, for obvious reasons, necessary in any case.

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

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

Vapor barrier materials: types, selection rules and prices

Modern industry offers many types of materials for waterproofing. Almost all of them are artificial polymers, because natural fibers always absorb moisture well and allow it to pass 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 will let through (1 square meter) for 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;
• ability to pass air, i.e. “breathe” while retaining moisture.

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

A comparison of the pros and cons of the most common materials is presented in the table (price - 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 by 1 meter (area 75 m2).

material	pros	minuses	price
single-layer polyethylene films	affordable price, easy installation	low mechanical strength, insufficient vapor barrier	1000
reinforced (double-layer) polyethylene film	affordable price, high strength	create a greenhouse effect	1400
polypropylene film	high strength and long term services		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 provide enough air - the walls must “breathe” the entire surface. In addition, warm air currents will penetrate into these cracks along with the moisture evaporated into them. 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 others. The reason is that membranes are a new generation material, different from traditional artificial polymers (polyethylene and polypropylene).

Their key advantages are as follows:

• allow moisture to pass through in an amount of no more than 10 g/m2 per day (they are especially often used in baths, saunas, and swimming pools);
• thanks to the porous structure, they retain condensation well, preventing it from penetrating into the insulation;
• withstand temperature changes 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 heat coming from the house - thanks to this, it helps the insulation maintain the internal temperature in the room in winter.

Thus, from the point of view 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 indicating the roll dimensions are presented in the table.

The main manufacturers of high-quality membrane films are German brands. High prices pay off if a major renovation of the house is planned, since if you make a calculation, then frequent replacement of 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 one or another part of the house, the following are distinguished:

• type A and AM - protection of insulation in walls and roofs from external influences;
• type B and C – protection of insulation in walls and roofs from internal moisture;
• type D – protection of the floor from dampness coming 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 external finishing walls with insulation;
• under the roof of the roof;
• into ventilation shafts.

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

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

Type AM

At the place of installation, this material is mounted in the same way as type A. It has a more complex multi-layer structure:

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

It is thanks to the diffuse film that steam escapes from the inside, but liquid does not pass through from the outside. Important Feature of this material - it does not need a ventilation gap, so it is mounted close to the surface of the insulation.

Spunbond refers to a special technology for the production of polymer moisture-proof film, as well as the product itself of this production. In this case, the fiber consists of artificial threads that are stitched together under the influence of chemical substances, heat or using water jets.

The result is a very durable 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 structural features of the multilayer material.

Type B

This 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 intended to create a living space in the attic with the possibility of year-round residence(like an attic).

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

Multilayer materials additionally protect from wind, and foil materials retain heat inside by reflecting it from its surface.

Type C

It is a particularly durable 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;
• basements;
• plinths;
• verandas, canopy.

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 heavy mechanical load is expected (pressure from furniture, movement and wind exposure).

Methods for fixing 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, since they are expected to be affected by constant load. There are several types adhesive tapes, which correspond to the considered types of waterproofing membranes:

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

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

• frame house;
• house made of timber.

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 cold winds, a layer is almost always installed that protects against them. And waterproofing is installed in cases where the house is quite old and the walls need to be protected from the destructive effects of moisture.

Vapor barrier from inside

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

The sequence of actions is as follows:

• If the house is built from a cylindrical beam, then due to its natural rounding it creates a sufficient gap for moisture removal - in this case, the membrane is attached directly to the logs using a stapler.
• Next comes the sheathing 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 beam through small wooden beams the same sizes. They are located at a certain interval and hold the insulation, on top of which a vapor barrier is placed. The same technology is proposed for a frame wooden house.

Clear installation method internal vapor barrier can be seen here.

Possible errors that are important to take into account immediately when laying the layer are presented in the video.

NOTE. The 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 fit tightly to the insulation.

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

The technology is as follows:

Features of the technology are shown in the video.

The external vapor barrier membrane must allow air to pass through well. The use of polyethylene, polypropylene and other films in this case is unacceptable, since the moisture leaving the house will encounter a barrier and will not be able to go outside - it will settle on the walls and insulation, which is why they will begin to rot.

Vapor barrier and insulation: what is the ratio

Since 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 especially necessary, and in which cases it is enough to simply cover the walls, for example, with plastic film. In this sense, there are 2 options:

• If polystyrene foam, 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 literally 1-2 years.

If the house is old and made of wood frame or infill construction, a moisture retention layer will be needed anyway 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 service life of the insulation and wood.

Wood is a living material, it main feature- ability to breathe. IN wooden houses natural air exchange occurs, and steam from the interior easily goes out into the street without lingering in the wood. Today many owners wooden houses they try to further insulate their home, turning its walls into multilayer cake from thermal insulation, waterproofing and decorative finishing. 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 learn why it is needed, what material can be used for steam and waterproofing of the external walls of a log house, as well as methods for attaching the insulator.

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

When air exchange occurs naturally in the house, steam freely leaves the room and goes outside. Now imagine that a multilayer barrier has arisen in the path of the steam. Condensation gets into the insulation and lingers there.

This happens day after day, and 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, rotting and destruction in the wood.

Avoid such unpleasant consequences allows a vapor barrier, which becomes a protective barrier on the path of steam, preventing moisture from entering the insulation.

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

Regardless of how the insulation is performed, it is necessary to choose the right vapor barrier material. If thermal insulation is performed with an unsuitable material, a greenhouse effect may occur when insulating from inside the house, 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 a material to withstand a certain amount of liquid, the higher this indicator, the better.
2. Vapor permeability, maximum density of transmitted water vapor.
3. Waterproofness, this property is especially important for 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 of 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.

Polyethylene vapor barriers are usually used for cost-saving purposes, since, 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 become deformed during operation.
2. Short service life.
3. In interior spaces a greenhouse effect can be created at home, so when using it, it is necessary to equip a forced ventilation system.

The film is destroyed when exposed to sunlight, which limits its use only to internal surfaces; it is often used for.

Polypropylene films are much stronger and more durable than PE films. The material is resistant to temperature changes and ultraviolet radiation. 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 of walls have a multilayer structure, which alternates layers with vapor barrier properties and a reinforced fabric, which 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 to facilitate rapid evaporation of moisture.

Vapor barrier membranes

The vapor barrier breathable membrane does not interfere with air exchange and improves 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 was specially developed for vapor barrier of baths, saunas and steam rooms, where conventional insulators are not suitable. On one surface of the film there is foil, which is reflective and at the same time reduces heat loss.

Foil materials include:

• metallized kraft paper;
• metallized kraft paper with mylar coating;
• fiberglass base with foil.

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

Coating insulation

For basement walls and ground floors houses that are located in close proximity to the ground use mastics based on liquid rubber or bitumen. Mastic is a water-based polymer solution, which is applied with a brush directly to the walls of the house. After the composition has completely dried, a durable film is formed on the surface, protecting the wall from moisture and steam.

How is a vapor barrier performed on walls?

In wooden houses, a vapor barrier is usually located from the inside of the room, and hydro- and wind protection is located on the facade of the house. If the house is to be insulated from the outside under siding, lining or other finishing, a vapor barrier sheet is laid between the insulation and the wall of the house.

The wall pie for internal and external insulation is different. External insulation is usually done on an older home to make it more attractive appearance, while leaving wooden frame. Internal thermal insulation produced in new buildings after exterior finishing work has been completed.

Basic rules of vapor barrier

1. It is very important to monitor which side of the film is facing 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 be laid with an overlap of at least 10 cm.
3. The joints of the panels are sealed with double-sided tape, the width of which is at least 10 cm.
4. Near window openings you need to leave a reserve of canvas for deformation of the material.

Vapor barrier of walls inside the house

When performing internal vapor barrier, so that an optimal microclimate is established in the room and the opposite effect does not occur when moisture condenses inside the house, you must strictly follow the work technology.

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

1. On interior walls fasten wooden sheathing. First install vertical racks on both sides of the wall, then in between. The width of the step between the slats depends on the size of the insulation and the type interior decoration. For example, under plasterboard it will be 60 m; when covering with clapboard, a distance of 40 cm is sufficient.
2. Insulation is placed between the slats; it should 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 laid overlapping each other, gluing the joints with double-sided tape. Then the film is fixed to the wooden posts with a construction stapler.
4. Next, they install the counter-lattice for fastening finishing. The counter grille is necessary to create a ventilation gap between the sheathing and the insulation.
5. Finishing is carried out.

Laying vapor barrier on external walls

When insulating a log house externally, you can attach a vapor barrier directly to the logs without leaving ventilation gaps. Their function will be performed by the natural voids between the logs.

It is impossible to attach a vapor barrier directly to the walls of a timber house, since the circulation of steam will be disrupted.

Vapor barrier installation technology timber houses as follows:

1. The frame is made from wooden slats minimum thickness 25 mm, which are placed at a distance of one meter from each other.
2. Sheets of material are placed on the frame, fastening them together with a special tape. Additionally, the film is fixed to the wooden posts using a construction stapler.
3. A counter-lattice is mounted on top of the vapor barrier.
4. Insulation boards are laid inside the frame.
5. Hydro-wind is pulled on top of the frame protective film.
6. Decorative finishing is being carried out.

U frame structures there is no rigid base for attaching the material, so the technology for laying vapor barriers is somewhat different.

The frame house must have the following structure:

1. External cladding (lining, siding, etc.)
2. Water and wind insulation, which is installed with air gap in relation to exterior decoration.
3. Frame with insulation.
4. Vapor barrier membrane.
5. Wooden sheathing.
6. Internal lining.

This wall pie is ideal solution for a frame house.

You can do the vapor barrier of log house walls yourself, but if done ineptly, this will lead to numerous errors and problems. The subtleties of this work are known only to professionals.

The Master Srubov company is ready to provide its services to residents of Moscow and the region. We guarantee high-quality and fast work on insulation and vapor barrier of your home. To ensure that your home is 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.

Wood is an incredibly breathable material that allows air and moisture to circulate well. However, this statement applies to whole wooden buildings, although nowadays they are almost never made. Wooden houses have been equipped with artificial insulation for some time, so the cut wall takes on a layered appearance. appearance. Since plastics or “foil” that do not allow air and moisture to pass through are often used as insulation, buildings have become much less durable. Due to moisture, which has no outlet, the wood becomes very decrepit and brittle. The solution to the problem is very simple - vapor barrier for the walls of a wooden house.

Where does moisture come from and how does it affect walls?

Where does moisture come from in a residential building is a simple question. Something often boils in the kitchen and produces steam, and the bathroom of some families does not dry out at all. In addition, every person sweats and breathes. As a result, the average family can produce about 150 liters per year! If the building also has poor ventilation, you can expect quick breakdowns and complete failure of the entire structure.

How does wood react to moisture? The porous surface absorbs it, changing both shape and size. We also introduce the concept of temperature into the equation. Result: wood is constantly changing under the influence of the above forces, and regular metamorphoses lead to loss of elasticity. As a result, within a couple of years from the moment the building was built, the wood becomes covered with various cracks and gouges. After a few more years, the least strong tree will become rotten and will crumble into pieces under the slightest influence.

By the way! Treated wood building materials are usually very airtight, so they are not affected by such problems.

Vapor barrier for the walls of a wooden house - why is it needed and what is it?

For a wooden house correct vapor barrier- This global issue. Walls need to be protected from moisture on both sides, that is, both outside and inside. However complex systems insulation is not always convenient to use. The vapor barrier membrane is the most best material, since it does not allow moisture to pass through and at the same time allows it to breathe.

The service life of a building directly depends on the correct installation of vapor barrier.

Types of vapor barrier. Vapor barrier for wooden and frame houses

Vapor barrier is primarily divided into external and internal. And if the external one can be started only 5 years after the construction of the building (when the tree has settled), then the internal one has to be done almost immediately. This leads to the fact that the sealing of the walls is broken. The scheme of vapor barrier work outside and inside is largely similar, but there are also differences.

Inside

Internal vapor barrier is necessary for life, so it is done right away. The process is very simple in words: insulation is installed on the timber, and a vapor barrier is installed on it. The material must be properly tensioned so that there is no sagging. It can be secured not only with a construction stapler, but also with ordinary nails with a wide head. Since the vapor barrier is usually installed in strips, it is necessary to install it overlapping (2-3 cm is enough) so that there are no areas without protection. In wet areas The procedure must be carried out with special care. After installing the protective film, drywall is usually installed. It's important to remember that wooden buildings are very specific and the best way out of possible problems would be to consult a specialist.

There must be a minimum of 0.3 cm between the final coating and the insulation free space so that the air circulates freely and the moisture has time to dry.

Outside

We begin work only after 4-5 years and when the building has completely settled. It is recommended to install a vapor barrier on bare timber before insulation. Installation on a timber building is carried out in the following order:

1. On the timber there is a vapor barrier secured with slats;
2. Lathing;
3. Insulation;
4. Waterproofing;

If your building is made of chopped wood, then the protective film can also be installed on the surface finished wall. Ventilation is carried out due to gaps in the material. A frame building is vapor-insulated in the same way as a timber building.

Tips for installing vapor barriers. Installation technology - how to attach to walls?

Vapor barrier materials vary greatly, so the methods for installing them also vary. First, it’s worth talking about the cheapest, but short-lived, materials. Regular polyethylene film easy to install, but very unreliable. If you really want to decorate your home to perfection, we recommend taking a closer look at reinforced film. It is more expensive, but much more effective.

Polypropylene films work very simply - all the moisture remains on them and falls down in the form of drops. When choosing this material, you need to think about this nuance. They also use penofol and analogues. The peculiarity of this material is that it insulates both moisture and heat. It is installed strictly with foil inside the room.

Ruberoid is also used for these purposes, but it is short-lived and does not cope well with the task. We don't recommend it.

As mentioned above, the best option - diffusion membrane. Ideal for use, suitable for mounting in several layers. It allows air to pass through, but does not allow moisture to pass through. Its price is very high. But the quality exceeds all expectations. In addition, we categorically do not recommend budget analogues - they do not work, and if they work, they work poorly and not for long.

When purchasing materials, pay special attention to their purpose. Often identical materials are responsible for different goals. For example, there are waterproofing membranes, which allow steam to pass through. When installing the wrong material, the whole essence of vapor barrier goes away.

A feature of laying vapor barrier materials is right choice sides. That is, you take a roll and you need to determine which side to glue it on. Manufacturers often indicate this nuance on the packaging, but if you did not find this information, then you need to apply the outer side of the rolled roll to the log. Secure with slats.

Vapor barrier is one of the most important stages of building a house made of wood. 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:

1. If the base is insulated from the inside mineral wool. This is due to the fact that moisture negatively affects the properties of this insulation. To do this inside the building.
2. Frame houses, the walls of which consist of more than one layer.
3. If brick walls insulated from the outside with mineral wool and. In this case, the vapor barrier will perform a windproof function, which protects the walls of the house from strong blowing. The ventilation gap removes excess moisture from the windproof layer.
4. For external walls located in close proximity to the foundation, where condensation forms most actively.
5. Walls made of logs or timber with natural moisture. Drying of such timber is carried out directly in the clearing, and the tree reaches optimal humidity no earlier than after 5 years. Maximum degree moisture content changes during the first year, so the beams are erected under the roof and left to dry for at least a year.

From which the walls of a house are built, it is dried to low humidity at the stage of its production, it has sealing grooves, slight variations in size, and also slight shrinkage.

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

Therefore, walls built from timber are a good vapor barrier. Often they do not require additional protection.

Laying a vapor barrier for a wooden house can be done a year after its construction. This allows you to preserve thermal insulation and reduce the level of vapor passage.

It is not recommended to install a vapor barrier on both sides; this prevents the natural drying of the wood.

Vapor barrier of external walls

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

1. When constructing the walls of a house from round log the insulation layer is attached directly to the tree using a construction stapler.
2. In this case, ventilation gaps are not required; it will be provided by the voids formed at the junction of the beams.

If the beam has a rectangular or square cross-section, the surface is smooth and air movement is insufficient.

1. Then planks 2.5 cm thick are stuffed onto the logs with a step between them of 1 meter. Vapor barrier material is laid on the completed sheathing and secured with a stapler. To provide vapor barrier, the following materials can be used: Ordinary polyethylene film. It should be noted that
2. 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 perforating the film with your own hands, that is, making many small holes on the roller on which nails are mounted.
3. However, this option is not advisable; the resulting 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. This material is capable of allowing air to pass through 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 helps the penetration of steam from the insulation into the interior of the house. The quality of the film depends on the vapor permeability index; the higher it is, the better. The price of membranes ranges on average from 750 to 4,500 rubles per roll. Mastic.

The material is intended to be applied to the base prior to completion.

facing works . The cost varies from 32 to 92 rubles per 1 liter. not recommended.

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

The redistribution of temperatures and moisture content in the insulated base layer may be such that on the inside of the film the temperature will be lower than the temperature necessary to cool the air so that the steam begins to condense into dew. This promotes 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 required along the line of the base and the film, thanks to which the temperature in the room is set equal to temperature room, that is, exceeding the dew point.

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

Vapor barrier of walls from inside a wooden house

Vapor permeability wooden base largely depends on the tightness of the sealing of seams, grooves, as well as the absence of cracks in the wood.

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

Vapor barrier can be done on the inner surface of the tree, but such a solution will not be entirely correct. The best option - installation of sheathing, which will subsequently serve as a frame for the internal cladding.

To do this, wooden planks are placed on the base surface in a vertical direction, which are leveled (wedges are placed along the depressions, and the material is removed on the protrusions). First, the outer slats are set, along which the intermediate slats are aligned using a thread.

The insulating material is stretched onto the sheathing from the bottom up and secured using a construction stapler.

It is necessary to lay the insulation in such a way that the matte rough side is directed inward, this reduces the formation of condensation. There is no need to stretch the film very tightly, since after a while the wood will dry out, the tension may increase and the vapor barrier will simply break.

The canvases are overlapped and taped with moisture-proof adhesive tape.

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

To install a vapor barrier indoors, the following materials are used:

• polyethylene film, the thickness of which is more than 0.1 mm;
• membrane film;
• mastic (excellent for plasterboard bases, the material perfectly allows air to pass through 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.

To effectively install a vapor barrier layer, you must adhere to certain rules:

1. Inside the house, vapor barrier materials are mounted on the walls, which divide the living space into zones. These areas are often insulated with mineral wool, which, accumulating moisture, loses its positive properties. Therefore, it is recommended to lay a vapor barrier on top of the insulation.
2. It is best to attach the film to the inside of the base wooden planks, pre-treated with an antiseptic.
3. It is laid on both sides of the partition bases. At the junction, an overlap of approximately 2.5–3 cm should form between the panels, 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 installed with inside

1. thermal insulation layer. Materials that prevent steam penetration often confused with waterproofing materials
2. , therefore, when purchasing, you should pay attention to what purposes they are intended for. To provide high-quality insulation
3. from the inside of the walls, it is necessary to maintain a distance from the film to the finish of at least 3 cm. This promotes free air circulation and the removal of moisture formed on the membrane. Vapor barrier material reduces wall ventilation to zero,
4. Therefore, it is necessary to install auxiliary ventilation, such as valves on windows, fans in walls and vents.
5. Due to the fact that certain internal claddings have their own vapor barrier, layers in the thickness of the wall should be placed so that the vapor barrier properties increase from the inside to the outside. During installation, the material must adhere tightly to thermal insulation material , firmly attached to components
6. installation systems. There should also be no loose areas or sagging.
7. Before installing a vapor barrier layer, it is necessary to check the surface of the base for seams and cracks and seal it with a sealant.