Today, during the construction and repair of various objects, vapor barrier is used. This material serves a number of functions. There are many types of vapor barrier on sale. It is produced by various brands. If the manufacturer has not provided instructions in the delivery kit for the use of this material, you can use the general recommendations.

There are certain rules on how and on which side to lay the vapor barrier. Knowing this technique, you can independently mount the vapor barrier. It’s not hard work.

Purpose of vapor barrier

Before you start studying which side to lay the vapor barrier on, you need to consider its purpose and features. During the construction or renovation of a building, the owners of houses and apartments insulate walls, ceilings, roofs, etc. However, all the costs of purchasing thermal insulation and other finishing materials will be inappropriate if a vapor barrier is not installed during the installation process.

Indoors, humidity levels may rise. This happens, for example, in the process of cooking food, drying clothes, watering plants, etc. The building materials from which the structure is made, to one degree or another, allow moisture to pass through. Only glass and metal do not have this property.

Condensation occurs due to temperature changes inside and outside the premises. The level at which it drops out is called the dew point. Most often it is located inside a wall or roof structure. This is where the temperature front passes. Moisture from condensation can accumulate inside the insulation. In the cold season, it can freeze, which leads to the destruction of building materials. When warming comes, the ice will melt, seeping through the walls or ceiling. Also, moisture accumulated in the insulation can lead to a decrease in the thermal insulation properties of the material.

Laying a vapor barrier prevents the ingress of moist air from the room to external insulation materials. In this case, it will be possible to avoid the insulation getting wet. The dew point will then shift. The installation of a vapor barrier will not only prevent the insulation from getting wet, but also prevent the development of mold and mildew. It is these microorganisms that cause the destruction of the wooden truss system and the establishment of an unhealthy microclimate in the room.

Varieties

In order to properly install a vapor barrier, it must be selected correctly. There are several types of submitted materials. They differ in their performance and installation method. The following varieties are on sale:

1. Liquid material for coating surfaces.
2. Rolled vapor barriers. They may include various impregnations.
3. Adhesive sheets or rolls.
4. Polyethylene film.
5. Foil vapor barrier. One side has an aluminum coating.
6. A membrane-type vapor barrier, which permits steam to a certain extent, has the ability to "breathe".

Each of the listed materials has its own area of \u200b\u200bapplication. The result of construction and repair work depends on the correct choice of the type of vapor barrier.

Rolled varieties with impregnations contain bitumen or resins. Such materials are used for arranging temporary isolation during the construction of facilities. Such a vapor barrier is difficult to install, since its joints are sealed with a gas burner.

Lubricants are quite expensive. Therefore, they are almost never used when arranging walls and ceilings. This type is more often used as a vapor barrier for concrete floors in wet rooms (bath, washing, etc.).

Adhesive-based materials (sheets and rolls) are used to isolate joints on building materials or in places where communications are installed. It is quite difficult and unprofitable to completely finish the walls and ceiling with such material.

Polyethylene film

Vapor barrier of walls from the outside can be done with polyethylene films. It is an easy-to-install material that can be mounted on either side. The front and back surfaces of this material are identical.

The scope of the presented vapor barrier is limited. It is most often used as temporary protection from wind and precipitation during the construction of various facilities. This is due to the operational characteristics of this material. It ensures complete sealing of the surface on which it has been laid. Condensation may appear on the surface of the polyethylene when the temperature changes. It gets into the insulation layer. To prevent this from happening, you need to provide high-quality ventilation of the facility.

The presented material can be used as a vapor barrier for concrete floors. However, in this case, a number of disadvantages of polyethylene should also be taken into account. This is an inexpensive and rather fragile material. Its service life is short. Under mechanical stress, the film may deform and tear. Also, temperature changes affect the material. From this, the material can also deform.

Vapor permeable membranes

Vapor barrier of walls, ceilings and ceilings can be done with breathable materials. These are multi-layer structures with high functionality. Each of the constituent elements of such a vapor barrier performs specific functions.

Each layer has holes for the passage of air masses. The first layer has small holes. This allows you to cut off part of the moisture without letting it in further. The second layer can be reinforcement. It should be said that the reinforcing layer is not present in all vapor barrier materials.

The reinforcing layer has large enough cells. They do not impede the passage of moisture further to the third layer. Power threads prevent material deformation and extend its service life. It is recommended to purchase three-layer type membranes.

The upper third layer has holes of a fairly large diameter. This allows you to provide the necessary air draft. It does not stagnate inside the material. Some of these heaters may have a rough structure as the top layer. It is made from natural fibers. Moisture is retained in this layer. Its removal occurs naturally.

The installation of a vapor barrier with a layer of viscose or cellulose involves the creation of a ventilation gap between it and the finishing. The gap must be at least 2.5 cm.

Vapor barrier properties

The vapor barrier of the ceiling can differ significantly in its characteristics from the material used, for example, for external walls or roofing. To choose the right variety, you need to pay attention to the properties.

In terms of vapor permeability, there are three categories of membranes:

• Low vapor permeability. The material is intended for partitions and dry rooms. During the day, he is able to pass through himself up to 300 mg of moisture per m².
• Average vapor permeability. One of the most commonly used types of membranes. Suitable for temperate climates. A vapor barrier falls into this category, which is capable of passing through itself from 300 to 1000 mg of moisture per m² per day.
• Increased vapor permeability. This type of material should be chosen for thick insulation. This variety is intended for northern regions with a cold climate or for areas with high levels of humidity. The material passes through its structure more than 1000 mg of moisture per m² per day.

Knowing in what conditions the vapor barrier will be used, you can choose the best option. Only with the right choice can we hope for the quality of work on the insulation of the object.

If it is extremely important to keep warm inside the room, you need to purchase a foil vapor barrier. It reflects infrared waves well. Thanks to this, the heat will remain in the room for a long time. This is important when arranging an attic, bath, etc.

Izospan brand products

Today, many types of vapor barrier of domestic and foreign brands are on sale. The latter offer the consumer products at a fairly high cost. Domestic manufacturers produce quality materials at an affordable cost. The most popular are the Izospan and Technonikol vapor barriers. Their products are renowned for their quality.

The Izospan company offers domestic consumers vapor barrier materials based on polypropylene. Many varieties of materials have been developed for different operating conditions. The cost of the presented products ranges from 20 to 65 rubles. per m².

Several types of vapor barrier are in demand. They are used for objects located in different climatic zones. So, films of the hydro-vapor barrier type, windproof and heat-reflecting types of materials are in demand.

The Izospan vapor barrier has a specific marking. Films with the letter B are intended for facades and roofs. Category D is a universal type of vapor barrier. It can be installed on flat and pitched roofs, facades and floors. Class C membranes are designed exclusively for floor mounting. All of these varieties have a two-layer structure.

Three-layer types of vapor barrier of this brand are AM (for outdoor use), AS (wind protection), FB (for a bath).

Technonikol brand products

The Technonikol vapor barrier is also popular with domestic buyers. This is a well-known brand that is known for its quality and reasonable cost. You can buy a vapor barrier produced by Technonikol at a price of 13 to 65 rubles. per m².

The buyer can choose the appropriate type of vapor barrier from several existing types. Materials for pitched roofs, membranes that partially pass steam are in demand. Also for flat roofs, a vapor barrier is used with increased elasticity and strength. A film with reinforced reinforcement is on sale. It has three layers. There is also a universal vapor barrier, which is used for many types of construction and repair work.

The presented materials are distinguished by a mass of positive characteristics. They are distinguished by their high tensile strength. These are elastic materials. They prevent the formation of fungus, and also demonstrate high water resistance.

Vapor barrier "Technonikol" is fireproof. It is designed for use in the Russian climate. The products are certified and have an acceptable cost. These are high-quality products that are not inferior in their characteristics to products of foreign brands.

How the film is laid

Instructions for vapor barrier are usually supplied by the manufacturer with the material. However, some craftsmen do not know which side to mount this material correctly. If there are no instructions in the kit, you can use simple general recommendations.

For some types of vapor barrier, correct layer placement is extremely important. In polypropylene vapor-tight varieties, the reverse and front side are identical. In this case, it makes no difference which side to lay the material on.

However, one-sided films are most often on sale. These types primarily include anti-condensation materials. On the one hand, they have a rough fabric surface. It is with this side that such a membrane is mounted inside the room when arranging the ceiling. This rule is also typical for foil varieties.

In the case of fabrics and films with aluminum coating, installation is straightforward. However, the same cannot be said for diffuse materials. Such films must be accompanied by the manufacturer's instructions. Determining externally which side to mount the vapor barrier is, in this case, quite difficult. To understand which side to lay the vapor barrier on, you should also consider the color of the film. Most often, manufacturers make the outside brighter.

Features of installation for different objects

Installation of vapor barrier can be performed for different objects. For example, for a floor with the wrong side, you need to apply the material to the floor beams. However, for the ceiling, you need to unfold the film with the fleecy side inside the room.

For the roof, you need to choose foil types of materials. If a reinforced polyethylene film is used indoors, it is attached to the insulation by either side. Outside the walls, you need to apply wind insulation.

When installing a vapor barrier in a wooden house, you must first treat the natural material with an antiseptic.

Installation process

The vapor barrier is laid according to a certain technology. The surface must be prepared, treated with an antiseptic, debris removed, etc. The vapor barrier must be overlapped by at least 15 cm. The joints are glued with adhesive tape. You can fix the vapor barrier on the surface with a construction stapler.

If the room is not heated (for example, an attic), a vapor barrier is installed to the interfloor ceiling. In this case, you need to leave a ventilation gap.

The vapor barrier must be dry. Therefore, outdoor work is not carried out in rainy weather. The vapor barrier layer should adjoin closely to the insulation material.

Having considered how and on which side to lay the vapor barrier, you can carry out construction and repair work yourself.

Almost every living space needs a vapor barrier. What it is? What kind of material is best for a vapor barrier? And which side should I put to the insulation? These and other questions regarding vapor barrier and its installation are answered by our experts in this article.

1. What are the functions of a vapor barrier? The fact is that it is usually customary to install a heater from the inside of the room, and when it comes into contact with warm air, it can be covered with water droplets. Where does moisture come from? The explanation is simple: steam settles on the walls of the room and, when cooled, passes from a vapor state to a liquid state. To prevent such a situation, you need to install a vapor barrier.

Experts identify several main functions of a vapor barrier:

• increase in the service life of thermal insulation materials;
• protection of the room from excessive moisture.

The vapor barrier must be installed in rooms such as:

The vapor barrier is mainly installed on ceilings where a large amount of vapor settles. Walls that are not insulated from the outside also need it, but in this case, the vapor barrier will be laid outside the building.

1. Which are the best to use? The use of a particular type of vapor barrier material depends on the intended purpose of the vapor barrier - indoors or outside. Therefore, experts call the following main types of materials with the help of which the vapor barrier is mounted:

• painting (bitumen, tar, rubber bitumen mixtures, etc.) - applied directly to non-insulated surfaces (these can be roofs, ventilation pipes, etc.);
• film (films made of polyethylene, polypropylene, diffuse membranes, antioxidant films) - these types of vapor barrier materials are excellent for arranging private houses, both as the main vapor barrier layer and for installing an additional layer that acts as a protection against roof leaks.

1. Which side should you put the vapor barrier on? When laying vapor barrier film materials, it is necessary to take into account the basic rule: the smooth side is located directly to the insulation layer, and the rough side should face inside the room itself.

In the case when the vapor barrier material is equipped with an aluminum layer, it should be installed as follows:

• the rough side is applied to the insulation;
• the shiny, smooth side should face the interior.

On the contrary, they act when laying foam propylene vapor barrier materials:

• the smooth side must be attached to the insulation;
• turn the rough side into the room.

But these features of materials are taken into account in the presence of a layer of insulation that has already been mounted earlier on the insulated surface. If there is no insulation layer on the surface (for example, the outer sides of the walls of buildings), then the vapor barrier is attached directly to the frame:

• the smooth side must be facing the wall;
• the rough side directs the material to the street.

It is not difficult to determine the smoothness or roughness of the vapor barrier material: it is enough to run it over its surface with your fingertips. Note that the plastic wrap is the same on both sides - smooth. Therefore, installation is facilitated, such a film is laid with either side to the insulation.

1. Are there rules for laying a vapor barrier? Experts say that such rules do exist. There are several of them:

• the sheet of insulating material must be overlapped;
• gluing the canvases is made with a special fixer - construction tape (the only condition is to prevent air from entering);
• monitor the integrity of all layers of vapor barrier materials.

Be sure to check for defects - they should be absent on the vapor barrier material in principle. Since any crack, gap or hole can cause condensation of moisture, which will constantly accumulate on the interior finishing of the surfaces of the room (especially for the ceiling).

Experts advise that before installing vapor barrier materials, carefully read the instructions that come with them. This manual necessarily prescribes the main point, which side of the material for the vapor barrier layer should be considered external, and which - internal. Although, as already mentioned, this can be determined by eye and touch by some signs:

• different colors of the sides (the light side fits to the insulation);
• texture (styling depends on the characteristics of the material itself, as discussed in this article above);
• free rolling of the roll (the side which material is facing the floor is usually considered internal and fits to the insulation);
• the smooth layer is usually considered to be the inner layer, and the fuzzy layer is usually considered the outer layer.

When installing a vapor barrier, the main thing is to properly lay it to the insulation (if any). This will help preserve its thermal insulation properties and extend its service life. If the vapor barrier is not equipped, then the insulation materials, due to constant exposure to moisture, will gradually begin to deteriorate, which will lead to rapid wear of the main structural elements of the building itself. This is especially true for private residential buildings: it becomes cold inside the premises, and additional costs for heating or heating them will be required.

Which side to put the vapor barrier to the insulation?

Which side to put the vapor barrier to the insulation? Almost every living space needs a vapor barrier. What it is? What type of material is best suited for a vapor barrier

Which side to put the vapor barrier to the insulation

When insulating a roof or a room with a heat insulator (mineral wool, glass wool, loose foam) capable of passing and accumulating moisture, it is necessary to mount a vapor barrier layer. Moisture trapped in thermal insulation significantly impairs its performance properties, increasing thermal conductivity. In addition, due to the humid environment, wooden structures with which the insulation contacts quickly begin to rot and collapse. At the stage of preparation for insulation of a roof or a house, it is important to figure out which side to lay the vapor barrier to the insulation - a violation of the technology will lead to the fact that steam from the room will penetrate into the thermal insulation layer.

What kind of vapor protection is needed

Varieties of vapor barrier materials

The first question is the choice of material that will protect the insulation from moisture. The classic roofing felt and glassine, with the help of which the hydro-vapor barrier was carried out, gave way to modern polymer films with various operational parameters. Membranes used in construction are divided by vapor permeability into completely impermeable films and partially permeable (diffusion) films.

Manufacturers offer vapor barrier membranes of the following types:

• polyethylene film (can be used to insulate the roof or floor, the barrier is vapor and waterproof);
• reinforced polyethylene film (characterized by increased strength);
• aluminum foil film (used for internal insulation, mounted with a reflective side to the room - additionally helps to keep warm, primarily designed for use in saunas and baths);
• a film with an anti-condensation coating (prevents moisture condensation, intended for installation as part of structures with metal elements prone to corrosion - corrugated board, metal tile, etc., the film is mounted with the treated side to the heat insulator).

Reinforced polyethylene film If a completely impermeable film is used to create a vapor barrier when insulating premises in a house, it is necessary to provide for effective ventilation of the premises, which can remove excess moisture outside.

Vapor barrier films with a porous structure differ in their ability to diffuse. Due to the pores in the barrier, moisture from the insulation goes outside, due to which the heat insulator retains its operational properties, and metal structures in contact with it do not rust, wooden ones do not rot. Vapor-permeable membranes differ:

1. Pseudodiffusion. Up to 300 g / m 2 of vapor is passed during the day.
2. Diffusion. The amount of permeable vapors per day ranges from 300 to 1000 g / m 2.
3. Super diffusion. The evaporation rate exceeds 1000 g / m2.

The vapor barrier film of the first type is classified as effective protection against moisture and is used for internal insulation of structures (from the side of the room). If a pseudodiffusion membrane is mounted on top of a fibrous heat insulator on an outer wall, the vapor barrier will retain moisture in the insulation. For facade insulation, diffusion and superdiffusion membranes are suitable, which simultaneously serve as a wind barrier.

Superdiffusion membrane

Vapor barrier installation principles

Laying a vapor barrier is an important stage in thermal insulation of structures with fibrous materials that can accumulate moisture. The work is carried out as part of the repair or reconstruction of the house or at the stage of preparation for the finishing of a new building. It is necessary to know how to properly fasten the membrane webs to each other in order to provide a continuous layer that protects against moisture penetration, how to attach the film to the structures. Before laying the vapor barrier film, it is also necessary to determine which side it needs to be placed to the insulating material.

Preparatory stage

For insulation of a block or wooden house, arrangement of a bath, heat-insulating materials are used, which must be protected from moisture accumulation. For this purpose, a material that does not allow evaporation is mounted on the walls inside the house, on the ceiling or floor, on the inside of the roofing cake. Or a diffusion membrane for facade insulation.

At the preparatory stage, you should choose a vapor barrier option, taking into account the installation features and requirements for the characteristics of the film. Popular options include Izospan (and its analogue Megaizol), a membrane material with high performance parameters. The manufacturer offers a line of membranes with various technical parameters, which allows you to choose the material depending on the purpose - vapor barrier for roofs, ceilings, wall structures made of wood or concrete.

Those who plan to build a bath, not without reason, believe that the foil film will reliably protect the mineral wool insulation from getting wet and help maintain a high temperature in the room by reflecting thermal radiation. Along with the classic scheme "insulation + vapor barrier", ready-made non-combustible heat-insulating mats with a foil vapor-tight surface are used today.

We fix the reflective vapor barrier correctly

Before laying the vapor barrier, it is necessary to correctly prepare the surface of the structures. The preparation technology depends on the material from which the walls, floor, ceiling or roof are made. It also takes into account what work is being carried out at the facility - construction or repair:

1. When erecting a wooden house, all elements of wood construction must be treated with compounds against rotting, pest damage and fire.
2. During the repair work, the finishing is dismantled, the surfaces are cleaned, while:
   • wooden structures are treated with an antiseptic and fire retardant.
   • concrete and block structures are treated with an antiseptic if they are damp and there is a risk of mold, as well as in wet rooms.

Due to improper preparation of structures, walls, ceilings or rafter systems can eventually become unusable or become a source of fungal spores that can provoke allergies, an asthma attack, and an exacerbation of respiratory diseases.

How to install a vapor barrier on the ceiling

Installation of a vapor barrier layer on the ceiling is required when insulating a flat or pitched roof in a house without an attic, when insulating a basement, as well as living quarters above which there is a cold attic. The ceiling in the bath is also insulated and vaporized. Before laying the vapor barrier on a concrete slab roof, on a reinforced concrete or wooden floor from the inside, the surface of the structure should be prepared.

A canvas made of a film or a pseudodiffusion membrane should be solid so that there are no joints through which moisture can penetrate into the insulation. If the width of the roll material is not enough, the strips will have to be joined together. The recommended overlap of the canvases is from 10 to 20 cm, while the joints on both sides are carefully glued with reinforced construction tape.

Fastening the vapor barrier membrane Cloths made of foil film are laid without overlap - end-to-end, and the seam is glued with aluminum tape.

If the base of the roof or slab is a wooden structure, it is first necessary to lay a waterproofing membrane (continuous sheet) and attach it to the base (a vapor barrier material can be used).

Then, a heat insulator is placed in the gaps between the floor joists or rafters in the form of mats or rolled material made of mineral (basalt) wool. After that, you can lay the vapor barrier on the ceiling. If the thickness of the heat insulator corresponds to the thickness of the lag, a counter-lattice of slats should be nailed to create a ventilation gap.

The vapor barrier should be laid on the ceiling in such a way that the canvas along the entire perimeter goes onto the walls, and that all corners are closed. The joints of the canvases should fall on the floor joists - this will allow them to be securely fixed. To properly lay the vapor barrier on the ceiling, watch the tension of the canvas, it should not sag.

Installation on the ceiling

We will also consider how to lay a vapor barrier on a concrete floor. In order to insulate a ceiling or a flat roof made of a concrete slab from the inside, it is required to attach a waterproofing coating (vapor barrier film) to it using self-adhesive tape, and then mount a lathing made of bars or a metal profile.

The correct height of the lathing should be selected taking into account the thickness of the insulation and the ventilation gap, the installation step is 1-2 cm less than the width of the insulation, so that the mats made of insulation materials fit into the cells by the way. How to fix the vapor barrier to the crate will be described in detail below.

How to install a vapor barrier on the floor

Installation of a vapor barrier membrane on the floor using the technology is similar to how vapor barrier is performed for walls and ceilings. After preparing the base of the wooden floor during insulation along the logs, before laying the vapor barrier on the floor, a waterproofing carpet is mounted, which should bend around the logs. Then a mineral wool heat insulator is inserted between the lags. After that, the vapor barrier is laid, while it is important to know how to properly lay the film.

The overlap of the sheets of rolled material should be at least 10 cm, while on each side the joint is glued with tape. The resulting canvas is fixed in such a way that the overlaps lay on the floor logs, and along the entire perimeter the evenly stretched canvas went 5-10 cm onto the walls.

Insulated floor with air gap

Before laying the vapor barrier on the concrete floor, it is necessary to install the crate, between the elements of which the waterproofing and insulation will lie. Further work is carried out according to the standard scheme.

Fixing principles

If concrete structures or wooden walls are insulated, it is necessary to install lathing from bars. It is convenient to attach the film to the resulting crate, to the ceiling or rafter system using staples and a construction stapler. It is also possible to secure the vapor barrier with wide-headed nails or cap pads. It is advisable to use galvanized nails - they do not rust... Films and membranes are placed on concrete structures using a special connecting tape.

Overlap when installing vapor barrier

In order to properly fasten the vapor barrier, the canvas should be carefully tightened, and the fasteners should be placed with a small step - no more than 30 cm.The installation rules prescribe that you carefully consider the fastening of the canvas around the perimeter - it spreads and is fixed so as to exclude the possibility of moisture penetration into the insulation.

Before fixing the vapor barrier, make sure that the sheet is positioned with the correct side to the thermal insulation.

Which side to mount the vapor barrier material

Consider which side of the insulation is the film or membrane:

• polyethylene film (simple or reinforced) can be attached on either side - this does not affect the functionality of the barrier;
• the foil film is placed with the shiny side towards the room so that the barrier reflects heat;
• anti-condensation film is attached with the treated side to structures, fabric to the room;
• the membrane should face the smooth side of the insulating material, and the rough side towards the room.

Rule of laying vapor barrier to insulation If the front side of the membrane looks like the wrong side, and it is difficult to determine how to properly lay the material, an experiment can be performed. A bowl of boiling water is covered with a small piece of membrane - which side of condensation appears, that side is waterproof, it should face the insulation.

It is important to know which side to put the vapor barrier to the insulation, if the membrane is used to install the waterproofing barrier - front or back. The thermal insulation "pie" with internal insulation is mounted in such a way that the smooth side of the membrane faces the insulation on both sides. That is, the rough layer of the vapor barrier should be directed towards the room, and when installing the waterproofing carpet - towards the structure that is being insulated.

Installation features

It is important not only to correctly lay the vapor barrier, but also to provide a ventilation gap between the vapor barrier layer and the structure cladding for finishing, for which counter-battens are filled on the crate. Moisture settling on the rough side of the laid vapor barrier will naturally evaporate without damaging the finish.

Scheme of insulated roof with ventilation gap

If the vapor barrier is installed correctly, the insulation is reliably protected from moisture. Almost half of the problems associated with freezing and damage to structures are associated with shortcomings in the installation of the vapor barrier.

Which side to lay the vapor barrier to the insulation, how to fix it correctly

Which side is the correct way to put the thermal insulation material to the insulation. Varieties of vapor barrier films with stages of installation on the roof, ceiling and floor.

Which side to lay the vapor barrier to the insulation. Types of vapor barrier materials. Installation of vapor barrier

Very often there is a need for thermal insulation of premises from the inside. If you plan to do the work yourself, many questions immediately arise about how to do it correctly. And one of them concerns the need to use vapor barrier films and their place in the thermal insulation "pie".

We will answer right away: vapor barrier is necessary in case of using any moisture-absorbing types of insulation. Read on for more details.

Why do you need a vapor barrier

Insulation installed on the inside, even with an external cladding, is in contact with warm air of the room, which always contains water vapor. But under certain conditions, they pass from a vaporous state to a liquid, that is, into drops of water.

What are these conditions?

• Excessive vapor concentration for a given air temperature. The higher the temperature, the more water vapor the air retains in itself.
• Lowering the air temperature.

If the concentration of water vapor and the temperature inside and outside the room are approximately equal, vapor barrier is not needed - the vapor will not turn into water. But as soon as these parameters inside the room become higher, the steam tends to escape outside through any obstacles.

As you can imagine, in our climatic conditions this happens during the entire heating season, which lasts more than six months. It is also clear that the coldest surfaces in the house are the surfaces in contact with the outside air: walls, ceilings above unheated basements, ceilings on the last floors, etc. That is why they are insulated.

Thermal and vapor barrier for walls

In the absence of a vapor barrier, steam penetrates into the layer of thermal insulation adjacent to cold walls or other structures, where it condenses, turning into drops of water and moisturizing the insulation.

As a result, the thermal insulation properties of the material are reduced, and it begins to perform its functions worse. And if the water does not have time to evaporate, then more serious problems are possible: damage to structural elements in contact with the insulation, the appearance of mold.

If the vapor barrier is installed under the insulation, then it becomes an impassable (or partially passable) obstacle for steam. It stays in a warm room without cooling and remains in a gaseous state.

Therefore, the device of internal thermal insulation clearly requires the installation of a vapor barrier between the insulation and the warm air of the room.

It doesn't matter what you insulate: walls in the room, ceiling, floors or roof. Without high-quality vapor barrier, you will not achieve the desired effect and can even harm the microclimate in the room.

Types of vapor barrier materials

• Film

Insulation Izolon is a multifunctional material).

Attention! Since reliable vapor barrier does not allow water vapor to be removed from the room through insulation and walls, it is necessary to provide good forced or natural ventilation in it. Its absence can lead to an excessive increase in air humidity and, as a result, to a violation of the comfortable microclimate and damage to the finish.

Vapor barrier construction rules

It would seem that there is nothing complicated: fix the film over the insulation and the vapor barrier is ready (See also the article Shelter Insulation - Technology of the New Time). However, there are some nuances in this case that you need to know about.

Types of vapor barrier materials

Among the materials for vapor barrier presented on the construction market, three main types can be distinguished:

• Film... Refers to the type of deaf vapor barriers, which absolutely do not allow water vapor contained in the air to pass through. Its main advantage is its low price.

In addition to ordinary polyethylene films, special, steam-condensate films are also produced. They are two-layered, with a smooth inside and a rough outside. The condensation droplets are held back by the rough surface and evaporate rather than flow down.

Vapor barrier membrane

• Reflective (energy saving) film... It has a metallized outer layer that is resistant to high temperatures and reflects most of the infrared radiation.

This material is most often used in baths and saunas

Installation of vapor barrier

From all the above, we can conclude that the vapor barrier material is attached over the insulation from the side of the room. But it is very important to take into account two more points: which side of the insulation is placed on the vapor barrier and what are the features of its installation.

This is where you need to look at the type of film used.

• Plain plastic wrap can be placed on either side. However, they do not differ from each other.
• The steam-condensate film is laid with the smooth inner side on the insulation, and the fleecy side looks out.
• In the same way - the smooth side to the insulation - diffusion membranes are mounted.
• Energy-saving vapor barrier materials are attached with the foil side outward, since it is this that reflects the heat that penetrates back to it.

Note! It should be remembered that the installation of solid vapor-tight materials requires a ventilated gap.

The fact is that with excess air humidity, deaf vapor barriers contribute to the creation of a greenhouse effect. If the inner lining is installed without a gap, close to the vapor barrier, then it will be constantly exposed to the harmful effects of moisture deposited on the film. If there is such a gap, the movement of air in it will facilitate the evaporation of condensate.

Insulation of the loggia using a vapor barrier membrane - no ventilated gap required

Which side to lay the vapor barrier to the insulation: do-it-yourself video instructions for installation, photo and price

Which side to lay the vapor barrier to the insulation: do-it-yourself video instructions for installation, photo and price

Which side should the vapor barrier be laid to the insulation

In the process of thermal insulation of buildings, it is necessary not only to lay insulation, but to create a whole "pie" consisting of layers that perform various functions. To protect the insulation materials and the structure itself from steam penetration and condensation, a film or a special membrane is used. For it to work, it is important to know which side to properly lay the insulation to the insulation used. Improper installation will negate all efforts to heat insulation, allowing the insulation to get wet. In addition, moisture will negatively affect the material of the building's structural elements.

Purpose of vapor barrier

Steam and condensation have a significant effect on the state of structural elements of the roof, walls, floor. Excess moisture promotes the growth of mold and mildew, corrodes metal and rotting wood parts. Wet insulation, especially mineral wool, sharply reduces its insulating properties, allowing the penetration of cold. The vapor barrier sheet serves as a protective barrier that does not allow wet steam to pass into the "cake", but does not prevent it from escaping.

The appearance of condensation provokes a temperature difference in a heated room and on a cold street. The steam striving to leave the building cools and turns into water droplets. The vapor barrier film, installed on the right side, prevents moisture from getting to the insulation. Condensation flows down the surface of the canvas, without getting on the structural elements, or dries on it. Some products designed for protection from steam do not require you to choose which side to turn them towards the insulation. These versatile films are especially handy for beginner builders.

Types of vapor barrier materials

A wide range of vapor barrier materials allows you to choose a canvas for any part of the building. The following are used as special protection:

Rules for installing vapor barrier film

To determine which side you need to turn the canvas towards the insulation, it is often enough to read the manufacturer's instructions. If there are no instructions in it, then the texture of the product will help you choose the right side. The smooth side of the vapor barrier is laid on the insulation, this ensures a snug fit, and the fleecy one serves to retain steam. Manufacturers of diffuse membranes always give detailed instructions for their use, and the outer part is painted in a brighter color.

The release of vapor barrier products in rolls facilitates installation and allows it to be completed in a short time. The standard width of the canvases is 1.5 meters and the length is 50,100 meters. To calculate the required amount of material, find the total surface area to be insulated, and then add 15% for overlaps and undercuts. The fastening method is chosen depending on the material used; it is better to fix the plastic film with wooden slats into which the staples are hammered. This will eliminate the possibility of damage to the polyethylene.

It is convenient to use a stapler to attach the vapor barrier sheet

Installation of canvases on the walls is always carried out from the bottom up. In difficult places - corners, ledges, slopes, the tightness of the fit of the material is ensured by gluing with adhesive tape. To work, you need a set of simple tools:

• construction knife;
• tape measure and pencil;
• scissors;
• stapler with staples or hammer and galvanized nails.

Ceiling mount

Due to the rise of heated air, including steam, the ceiling is one of the most vulnerable places in the room. An effective option for its protection is a special membrane. These canvases are offered in two types:

• one-sided - for operation, you do not need to choose how to properly install the insulation in relation to the insulation;
• double-sided - the membrane must be mounted on the side indicated in the instructions.

Such material does not require leaving a gap for ventilation, eliminating the need to create a counter-lattice. Installation costs will decrease, and the ceiling height will change slightly. The membranes are strong enough, you need to use small nails or staples of a construction stapler to fix them.

The vapor barrier must be installed after installing the insulation. The canvas should not be stretched too much, because during operation it shrinks and stretches when the temperature changes. Excessive tension can lead to rupture, especially for products installed in an unheated room. Large sagging is also not needed, 1-2 cm is enough. Spreading material, part of it is put on the walls in order to dock with their vapor barrier.

We isolate the roof from steam

When installing a vapor barrier for roof insulation, you can use a film material made of two layers of polyethylene, reinforced in the middle with a metal mesh. It will also be a good waterproofing. Installing the film requires leaving an air gap of at least 5 cm, so there must be free space between the insulation and the edge of the rafters. If the angle of inclination of the slope is less than normal, it is worth using an adhesive-based film. This will greatly facilitate installation, increase the tightness of complex joints. For reinforced concrete roof slabs, liquid bitumen mastic is used as a vapor barrier.

To protect wooden structures, special vapor barrier films or membranes are used

Work with insulated facades

The placement of a vapor barrier product on the outside of the walls has its own nuances. They are due to the change in temperature regimes, the presence of precipitation, and wind load. Let's figure out how to lay a vapor barrier for facades. The cloth fits snugly to the insulation (if necessary on both sides), a gap is left between it and the cladding for ventilation. The material must be carefully secured so that the wind does not blow it away. Usually a membrane is used, in which it does not matter which side it is laid on the insulation. Horizontal and vertical stripes overlap each other by at least 10 cm, this will ensure the tightness of the joints. Bonding the parts with butyl tape ensures high bond strength. The drainage of condensate flowing down the vapor barrier film is carried out through the drain holes in the lower part of the wall.

Installing the film on the insulated floor

When vapor barrier of the floor insulation placed between the logs, the strips of material are stretched across the wooden logs. Fastening with staples. The joints to the wall and the overlaps of adjacent panels are sealed with double-sided adhesive tape. Steam from the room penetrates from above, so the film is laid with the rough side up.

Features of the installation of reflective vapor barrier

Cloths with a layer of aluminum foil are necessary in rooms that require maximum heat retention. When they are installed, the reflective layer is always directed into the room. A gap is left between the insulation and the finishing, it will strengthen the effect of the foil and prevent damage to the lining by the resulting condensation. Neighboring canvases are installed end-to-end and glued with a special metallized tape. If the tightness of the surface of the product is broken during fastening, then the hole is sealed with tape.

Which side to the insulation to lay the vapor barrier

How to properly lay a vapor barrier to protect the ceiling, roof, walls, floor. What material is better to use and which side should it be laid against the insulation.

First of all, you must follow the manufacturer's instructions, which clearly describe which side to lay the windscreen. If there is no such instruction, there are a number of general guidelines that apply to windscreens:

• the windscreen spreads to the insulation with the "fleecy" side, unless otherwise specified in the instructions;
• if both sides are the same, the film is attached with the manufacturer's logo outward;
• windscreens without markings and distinctive qualities of one of the sides can be laid in any convenient way.

Often, manufacturers roll up the rolls so that the windscreen is as easy to lay as possible - in the course of unwinding the roll.

Windproof films of different types, fit in different ways:

1. Simple wind protection. These are perforated single-layer films that can spread either side to the insulation, as they have two-sided vapor permeability.
2. Wind-moisture protection. These are two-layer films that are laid with the moisture-repellent side out. This side is smooth, often with manufacturer's markings or painted in a color other than white.
3. Superdiffusion membranes. This material has a multi-layer structure with high water resistance and vapor permeability. It is necessary to lay the membrane on the outside of the insulation and only with the marked side out.

Laying the windscreen on the floor

On internal ceilings, the film is spread over the insulation with the marking outward, and the plain side inward.

And to protect the wooden floor from being blown by the cold wind from the uncovered basement of the columnar foundation, the film is laid on the subfloor without gaps close to the insulation. In this case, it fits with the inscriptions down.

How to install a windscreen on the roof

Single-layer wind protection films are placed under the roof on either side. But two-layer ones - only the smooth side up.

Some films and membranes are UV resistant thanks to a special coating. The manufacturer must indicate this parameter. Such a windscreen is attached to the rafters with the colored (protective) side up.

How to install windscreens on walls

On the walls, the windscreen is placed from the outside directly on the insulation (with the marking or the colored side outward). It is necessary to provide a ventilation gap between the film and the external finish. In order for the windscreen to provide a sufficient level of protection against moisture, it must be fastened horizontally from the bottom up with an overlap of at least 10 cm. Inside, a vapor barrier is laid on the walls - very important

If, when insulating the building, you do not use a vapor barrier, then the insulation itself will last a very short period of time.

Moisture will begin to flow into its layers and will carry out the destruction process. This procedure very often occurs when it is cold outside, then there are large temperature differences inside and outside the room.

In order for the vapor barrier to be laid on the walls correctly, you should know its features, because not any side of the film can be used.

Purpose of vapor barrier

Vapor barrier will protect the house from condensation

Today, the topical issue is saving money on gas and electricity bills. To save money, more and more people insulate their homes and apartments, and to keep the insulation itself from moisture and steam, vapor barrier materials should be used.

For what exactly they are needed, you can find out from the table:

№	Highlights	Description
1	The vapor barrier preserves the building and the health of the residents.	Thanks to the protection against moisture, metal and wooden structures will serve for a long time, will not corrode and rot. In addition, mold or mildew will not appear in the house using the film.
2	If the house is insulated from the outside, then the vapor barrier may not be used.	In this case, the vapor barrier will need to be laid on the floor, ceiling or roof.
3	If the insulation is carried out inside the building, the vapor barrier is laid on the insulation materials.	In this case, the insulation will be able to serve for a long time and will not collapse.
4	The vapor barrier can be installed inside and outside.	If you ignore the installation of the vapor barrier, then in addition to moisture, heat will come out of the house.

Knowing the main tasks of the vapor barrier, we can safely say that its installation must be in any house, but to carry out the work on your own, you will need to know the features, as well as perform a number of preparatory measures.

In the case when the insulation work is carried out from the street, then the protective material must also be laid outside the premises. If it happens inside the house, the film is also installed indoors.

Preparatory work

Use membrane films in wooden houses

When preparing the protection of the house and insulation, you should start by choosing the vapor barrier itself, which will be used in the future. Today the choice is large enough, and films can be used not only for walls, but also for ceilings, ceilings, floors and other parts.

If the building is made of wood, then it is better to use films with membranes in the work. If the base is brick or concrete, then other types of films are possible, among which there are:

1. Polyethylene. The cheapest option. Using such a vapor barrier will require constant ventilation.
2. Polyethylene with aluminum. It is used to reflect heat energy.
3. Reinforced polypropylene. There are 1,2 and 3 layers. The composition includes viscose and propylene. Such material has one side smooth, the other fleecy.
4. Diffuser membranes. Protect from moisture and release it outside. The film retains heat well and "breathes".

Install insulation on walls impregnated with protective mortars

Incorrect preparatory work will result in poor performance of the film itself. Preparation will depend on what the house is made of, namely the walls. If the house is just being built, and wood is used as the main material, then all elements must be impregnated with insect repellents, mold, fungus and fire. After impregnation, you can proceed to the construction and insulation of the walls.

If the building is made of concrete, then there is no need to use impregnation. It will be enough to clean the surface from mold, mildew and dust. Further, the base will need to be checked for cracks and holes, if any, then putty them.

Vapor barrier films must be protected from sunlight, because in 3 months under the sun the insulation will be unusable and its properties will be lost.

In general, it is easy to install a vapor barrier and no special skill is needed. When the preparation is completed, you can start working, but you need to know that the film must be overlapped, and also additionally glued with tape.

This allows you to close the air access. Especially carefully it is necessary to paste over the places of contact with various openings. If a film with a foil layer is used, then the corresponding adhesive tape is also used.

Choose an adhesive tape according to the type of material

After buying the film, you need to familiarize yourself with the instructions, namely, which side needs to be laid to the insulation, but in practice such information is not always available and to determine the front side, you need to pay attention to the following factors:

On the wall is carried out according to the following instructions:

1. The film is applied to the wall and fixed with a stapler.
2. The next part overlaps and is also fastened with staples. All parts of the vapor barrier should not be stretched, the film is laid loosely so that there is room for ventilation.
3. When the film is laid on the walls, all joints are pasted over with tape, which will give maximum sealing.

During work, tearing of the film is not allowed, if this happens it is better to change the part or securely seal it with tape. The film itself must be dry before use. If you have to lay the film in the winter, then the heating must work in the house.

If the work is done correctly, then the film will not need to be serviced, and the walls will serve for a long time without repair. The work on laying the film on the floor and ceiling is somewhat different, but in general the essence remains the same. For more information on how to properly lay a vapor barrier, see this video:

During the work, a certain amount of vapor barrier should be left near the openings. It is necessary if the house shrinks or deforms. For the stock, a fold is made with dimensions of about 3 cm.

Read about the features in other articles on the site.

To properly carry out the work on laying the vapor barrier, you will need to study what such material is needed for. Knowing the features and installation method, the work can be done independently, in just one day.

When insulating a house, it is important to put the vapor barrier on the right side of the insulation. After all, if the norms are violated, cold will enter the house, and the heat inside will not be preserved. In our article, we will take a closer look at all the nuances of laying a vapor barrier.

Which side to lay the vapor barrier to the insulation

Before determining which side to install the vapor barrier, you should consider the places for laying the vapor barrier membrane:

• If your insulation will fit from the facade, then the vapor barrier should be fixed from the outside. Thus, you will make waterproofing;
• The space under the attic, for example, a ceiling or ceiling, requires laying a vapor barrier membrane underneath the insulation;
• When processing roofs and ceilings, an antioxidant vapor barrier must be used. Diffusion and volumetric coatings are in demand. They should be laid on top of mineral wool;
• If your roof and ceiling do not have additional insulation, then in this case, the vapor barrier is attached to the rafters from the bottom side;
• When insulating the floor and walls from the inside, it is necessary to additionally lay a vapor barrier film outside the mineral wool.

Many builders, even those with extensive work experience, do not pay attention to which side to attach the vapor barrier film to the insulation. When choosing a vapor barrier film, it is better to give preference to a material with the same front and back sides.

But many choose options with different sides, and often with an antioxidant isolator. In this case, you need to know that the fabric surface is the wrong side. It is placed in the interior of the room. The metal plane of the foil membrane should also be positioned. That is, the shiny side to the interior of the room.

Regardless of the vapor barrier material, it is laid with the rough side to the room, and the smooth side to the insulation.

When buying diffusion components, you should carefully study the instructions for use. Various manufacturers produce double-sided and one-sided vapor barrier films.

In most cases, the dark side of the film is on the outside.

What are the vapor barrier membranes

Membranes used in construction are:

1. Vapor permeable.
2. With vapor barrier properties.

When using mineral wool as a heater, an additional layer of vapor barrier is arranged on the inside to protect it from moisture. If the walls are protected from the outside, then the components should not contain pores or perforations.

When choosing, you need to pay attention to the vapor permeability coefficient. It should be as small as possible. Buying regular plastic wrap is a good option. The material that is additionally reinforced will be of higher quality. And if the vapor barrier has a foil-coated aluminum coating, then such a film will be of high quality and durable. The use of a vapor barrier in a room leads to an increase in humidity. Therefore, do not forget about the device of a high-quality ventilation system.

There is an antioxidant coating in special vapor barrier films. With its help, there is no accumulation of moisture on the insulation. They are often used in areas prone to corrosion. For example, in materials such as corrugated board, metal tiles and others. Rough seamy surface helps remove moisture. The fabric side should be facing outward, so that a distance of 2 to 6 cm is observed to the insulation.

A building membrane is used to insulate a house from the outside. It is able to protect the material from bad weather conditions, and carries out evaporation. Usually the vapor barrier has small pores and therefore the water is removed from the insulation into the ventilation ducts. Thanks to this, the insulation dries quickly.

There are several types of vapor-permeable films:

1. Diffusion membranes. The vapor permeability coefficient can be from 300 to 1000 g / m2.
2. Pseudo diffusion. They let through no more than 300 g / m2 of vapor during the day.
3. Superdiffusion membranes. The evaporation rate is more than 1000g / m2.

The pseudo diffusion type of vapor barrier is a high-quality protection against moisture, therefore it is often laid under the roof as an outer layer. Do not forget about the arrangement of the air gap. The disadvantage of this type is poor steam conductivity, therefore such a film is not used for facade processing. Condensation will begin to accumulate on the surface of the insulation, as dust and various debris will clog into the pores of the membrane.

In the other two types, clogging of pores is excluded. Therefore, you can not leave an air gap and additionally arrange a crate or counter battens.

In the membranes of diffusion films of volumetric design, a ventilation layer is provided in advance. The device of such a film is very similar to the antioxidant type. The only difference is the release of moisture from the insulation. With a slight slope of the roof, condensation will not drain through the bottom.

The need for an air gap at the membrane

It is always necessary to leave an air gap. A gap of 5 cm is arranged on the underside of the film. This way, you can avoid condensation on floors, walls or insulation. When using diffusion film, it can be attached to moisture resistant plywood, smallpox or thermal insulation. And the ventilation layer is arranged from the outside. When using an antioxidant component, an air gap of 4-6 cm should be made on both sides.

When installing a vapor barrier for the roof and ceiling, an additional counter batten made of wooden blocks must be installed for the ventilation gap. When installing horizontal posts and profiles that are perpendicular to the wall and the film, a gap should be left for the ventilated facade.

Vapor barrier fixing rules

You can attach the film to walls, ceilings or floors using a stapler or wide-headed nails. But the best option would be to use counter rails.

The vapor barrier film should be laid with an overlap of at least 10 cm. After fixing the vapor barrier, the joints should be glued with special tape or tape.

Membranes will help for the qualitative ratio of moisture and temperature of the building structure, as well as for a long service life. It is impossible to achieve such qualities without their participation. When laying a vapor barrier, all rules must be followed. Many manufacturers indicate on the packaging recommendations for installing a vapor barrier.