Which side to lay the vapor-permeable membrane to the insulation. Which side is the vapor barrier to the insulation? Rules for installing vapor barrier film

When carrying out construction work, as well as in the case of major repairs, it is necessary to comply with a number of requirements, among which the quality of the services performed takes a special place. The main task of each stage of construction is to make a reliable and high-quality base for all surfaces. To do this, you should gradually monitor that the surfaces are not only even and insulated, but also do not contain moisture. This is necessary so that the formation of mold and other fungi does not occur as a result.
Today there are several ways to achieve the desired result. So, the surfaces of walls, ceilings and floors can be treated with antiseptic agents or, for example, an ideal surface can be achieved by making a multi-layer leveling, which consists of two layers of hydro and vapor barrier. Moisture will not be able to penetrate into the room if the waterproofing work is performed with high quality. The vapor barrier prevents the formation of condensation.
The device of a vapor barrier is actually not complicated, but, nevertheless, it plays an important role in the construction of a building, since it is it that ensures a long service life of materials for construction.

The need for vapor barrier

Vapor barrier is a kind of special film (or various materials such as rubiroid), which, along with other parts of the building structure, prevents steam from entering the room and prevents condensation from forming.
Before proceeding with the vapor barrier work, it is required to determine the most critical areas. Protect areas that are in direct contact with warm and humid air.
Vapor barrier helps to increase the service life of the insulation, so it does not allow moisture to penetrate into the insulation layer. The properties of vapor barrier are especially relevant, during the period when the temperature in the house and outside the window is different, that is, in winter. For this reason, steam may form in the premises, which should easily escape from the building.
A vapor barrier is required for laying on the ceiling, basement rooms, attic rooms and, of course, on the first floors of buildings. It should be noted that the vapor barrier of the walls is optional if they are insulated from the outside. This is due to the fact that the vapor barrier in this type of building will run along the outside of the building. When using a technology in which the walls are insulated inside, it is necessary to lay a vapor barrier layer over the insulation.
The installation of a vapor barrier layer should be carried out depending on which part of the house is being insulated. Accordingly, the order of work will be different.

Types of materials intended for vapor barrier work

Despite the fact that the construction industry is at its peak of development, there is no universal material for vapor control of various surfaces.
The main characteristics of the material are fire safety, strength and a good heat transfer rate.
Since the vapor barrier layer can be laid both indoors and outdoors, various components are used for laying it. So, the following types of vapor barrier materials can be distinguished:
1. Paint vapor barrier, used when it is necessary to ensure watertightness and protection of external structures, for example, a roof or a ventilation pipe. For the specified painting method, the following materials are distinguished:

tar;
mixtures;
bitumen.

2. Film vapor barrier- a material that is used as a vapor barrier in the construction of private structures. Film-type vapor barrier material has several varieties:
There are several types of polyethylene film. Distinguish between perforated and non-perforated films, as well as films that are covered with a layer of aluminum. It is worth emphasizing that non-perforated material is used extremely rarely, this is due to the fact that it is rather weak and does not cope with its task.
Perforated polyethylene film is one of the most common vapor insulators. True, it should be applied extremely carefully, since it is susceptible to mechanical damage that can be caused in the process of fixing the material. In turn, if the film layer is damaged, the performance is reduced and may disappear altogether.
Today, polyethylene films are very popular, the coating of which is heat-reflecting. This material is covered with foil on top and is used, as a rule, in closed rooms where the temperature is elevated, such as saunas, baths.

Reinforced polypropylenethe films are highly durable and resistant to ultraviolet radiation. Thanks to these properties, the material is able to protect the structure of the building from the effects of rain and snow for a long time.
Diffuse membranes- a material with high vapor permeability and other positive characteristics that make it possible to distinguish it among its analogues. The only drawback is the high cost among vapor barrier materials.

3. Antioxidant vapor barrier films- are intended for use as an additional layer of vapor barrier when arranging the roof, in places where ventilation openings are located. In addition, they are used as an additional protective layer against roof leaks.

Also in construction, when providing vapor barrier, the following can be used:

Spunbond materials covered with polypropylene. It is used in the case of installation of cold roofs that are not heated in any way.
Metallized foil, including aluminum, is used when arranging a bath or a sauna, since one of its characteristics is high vapor permeability.
Laminated cardboard with polypropylene film is used for vapor barrier of a room in which cyclic heating is planned.
Bitumen or materials based on it, such as various types of emulsions and mastics. It should be noted that bitumens are distinguished into five types, depending on the melting point. So, if a low-melting material is required, then you should opt for grades from 1 to 3, but types 4 and 5 are refractory. Along with the fact that bitumen is used for vapor barrier, they also act as adhesives. A number of disadvantages of this material should also be noted, which include insufficient waterproofing and destruction if the thermometer goes down.

Correct installation of the vapor barrier

In view of the fact that a wide variety of vapor barrier materials is presented on the market today, the question arises of which side should be laid vapor barrier so that the insulation will serve for a long time and most importantly reliably.
Before proceeding with the vapor barrier work, a number of mandatory calculations are required. This is a simple procedure, as it might seem at first glance. It is enough just to calculate what is the area of each of the elements that make up the structure of the house and require special protection. When calculating, it is necessary to take into account the width of the vapor barrier material, plus clarify the dimensions of the overlaps.
You should also carefully prepare for the installation of the vapor barrier. And for this, a number of preparatory procedures should be carried out:

Previously, the surface must be cleaned of any kind of debris and dust;
The gaps are covered with special tools, for example, you can use a primer;
Thorough drying. How well the surface is dried depends on how the vapor barrier material will show its properties.

When laying the vapor barrier, it is very important to pay attention to the correct side of the material. To do this, first of all, it is worth determining its internal and external parts. Today, many manufacturers indicate information about which side should be considered internal, but if such information is not available, it should be determined from external data. To do this, you need to pay attention to such details as:

If the film for waterproofing has a different color of the sides, then the side that is light should fit to the insulation;
When rolling out the waterproofing film, it is easy to determine the inner part of the material, it is enough just to follow which side is facing the floor.
The inner part of the material for vapor barrier is smooth, it fits into the side of the insulation, as for the outer side, it is covered with pile, which is necessary in order not to let moisture through.

As a general rule, for any part of a room that has a two-layer structure, it is characteristic of laying the material with the smooth side to the insulation, and rough outward.
If the vapor barrier is covered with a layer of aluminum, then the shiny side fits inside, and the rough side, on the contrary, to the insulation.
Any material that is used for vapor barrier is overlapped, and it is important that one layer overlaps the other by at least 15 cm. The joints that are formed in this case should be glued together with adhesive tape. Fix the same vapor barrier on surfaces using a construction stapler.
There are several considerations when equipping a vapor barrier. So, if the room is unheated, then the vapor barrier layer is attached directly to the floor located between the floors of the building, it must be done in such a way that a gap is formed. After the work done, the so-called rough ceiling is laid.
When it is necessary to insulate the outer walls of the house, the vapor barrier is attached to the frame, while the smooth side of the material is located towards the wall, and the rough surface remains facing the street.

Which side to lay the vapor barrier on the floor

The vapor barrier is laid on the floor, depending on what material is used for insulation. The smooth side is located towards the insulation, if a two-layer polypropylene film is used, its rough side will be directed towards the source of moisture formation.
In the case of dismantling a floor made of foil-clad material, the side of the vapor barrier with a metallized base is laid directly on the insulation. In this case, it is very important that the vapor barrier is located on both sides at once, and above and below, and between the layers - insulation.

Ceiling vapor barrier

It is necessary to carry out vapor barrier works on the ceiling, especially if the room has a high degree of humidity. For this, materials such as foil, steam condensate double film and roll membranes are used. It is important to lay the vapor barrier in such a way that moisture does not penetrate the insulation. This means that when installing the ceiling, the smooth side must be positioned against the material intended to create heat, and the rough part will face outward. When foil is applied, the metallized side faces outward, that is, directly to the source of moisture. If this is not done, the properties of the insulation will be lost, and it will begin to accumulate moisture.

How to position the Izospan vapor barrier in relation to the insulation

The isospan vapor barrier is of several types, namely, the material of the "A" and "B" groups is distinguished. These types differ from each other in properties. Izospan, belonging to the first group, is used to protect the outer shell of buildings and roofs, prevent them from deterioration from moisture and wind. The specified material is a vapor-permeable film that does not allow condensation to form and affect the insulation. On the one hand, the film is rough, and on the other, it is smooth, like almost all vapor barrier materials. It is the rough part of the film that has the ability to absorb condensate and subsequently evaporate it into the air through the ventilation ducts. When performing installation work using isospan type "A", the vapor barrier is laid with the rough side to the insulation, the dense one turns outward.
Izospan, belonging to the "B" type, has the property of complete vapor impermeability. It protects the interior of the room from the effects of condensation. It has a two-layer structure, which is smooth on one side and rough on the other side, as in type "A". The peculiarity lies in the fact that this type fits to the insulation with the side that turns out to be smooth. The roughened side is responsible for trapping condensation and preventing moisture build-up.
So, in conclusion, it should be noted that the correct determination of which side the vapor barrier should be laid is of great importance for the well-being of the room. After all, a properly assembled vapor barrier design will not allow moisture to accumulate in rooms and other rooms.

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.

What are the functions of a vapor barrier? The fact is that it is usually customary to install the insulation 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. In order 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:

basements of residential buildings;
first floors of buildings;
attics.

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

What types of vapor control materials are 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.

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 where 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, already 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.

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;
the gluing of 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. In this manual, the main point is necessarily prescribed, 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 into 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 with which the material faces the floor is usually considered internal and fits to the insulation);
the smooth layer is usually considered to be the inner layer, and the fleecy one is the outer layer.

Vapor barrier is a layer that protects insulation or building structures from the penetration of wet steam, which in turn leads to the accumulation of condensate on them, loss of useful properties and rotting under the influence of moisture. To create a vapor barrier, completely impermeable double-sided or having one correct working surface of the film and canvas can be used. It is extremely important to determine exactly which side to put the vapor barrier on the insulation, an error at this stage provokes the accelerated destruction of building materials and significant financial costs. The main guideline is the manufacturer's instructions, but often this document is absent when purchasing, the choice is made taking into account the type of vapor barrier film and the installation conditions.

How is the vapor barrier installed?
Technology violations
Tips & Tricks

For ordinary or double-sided reinforced polyethylene, this problem is not relevant, in other cases, the working surface is a vapor-impermeable surface. Most often, the vapor barrier is laid with the smooth side to the insulation, and the protected side turns to the source of steam penetration. Depending on the type of materials, these are:

Laminate with cardboard (it is not recommended to put on critical objects).
Reflective side for foil and aluminum roll coatings.
A fleecy or rough surface in antioxidant films coated with viscose or cellulose.
The vapor-tight side of the membranes is usually brighter.

1. Laying the vapor barrier on the floor.

Protection from steam and moisture is required when insulating floors or horizontal planes, assembling structures from a bar. Reflective films that return heat to the house are considered optimal for the floor. During the construction or repair of the first floors, the insulation is protected with a layer of waterproofing, and on top - with roll vapor barrier materials laid with an overlap (from 10 cm and above) with gluing with metallized tape. The situation is slightly different when arranging attic floors and interfloor floors: the films are turned with the impenetrable side down to protect against steam penetrating through logs or slabs.

2. Vapor barrier of ceiling structures.

Most often, the need to close the ceiling arises in baths, saunas, kitchens, showers and other structures with high humidity. The greater the volume of vapors emitted and the higher their temperature, the more reliable vapor barrier is required from them. Dense aluminum, lavsan and antioxidant vapor barrier materials are well suited for protecting the ceilings of the steam room, for living rooms - the same, plus ordinary penofol. A prerequisite is an overlap of at least 10-15 cm and sealing of the joints; for reliability, the vapor barrier is fixed to the ceiling with a grid or brackets. In this case, the reflective or vapor-proof side is directed exclusively towards the interior of the room.

3. Vertical structures.

Installation of a vapor barrier for wall insulation is necessary when: using fibrous and wadded insulation, erecting frame wall panels, arranging ventilated facades, in the latter case, it also performs the functions of wind protection. In all the above-mentioned points, it is not recommended to choose completely impermeable films, the insulation must breathe, diffusion and superdiffusion membranes, which allow air to pass through, but not moisture and steam, are considered the best option. For outdoor work, the vapor barrier is laid with the smooth side to the mineral wool or other insulation on the walls, the rough side towards the street. The film or canvas should not sag, but excessive tension is also unacceptable. On internal vertical walls, they are held by brackets or upholstery with thin strips, the vapor-tight side to the room.

4. Roof vapor barrier.

The vapor barrier is an obligatory layer when laying the roofing cake. It prevents the accumulation of condensation in the inner insulating layer and protects the rafters from fungus. The maximum possible tightness is required from the vapor barrier, preference is given to antioxidant and reflective types, the vapor-impermeable side is directed towards the interior of the attic. Overlap - from 15 cm, as well as gluing joints and seams. An important condition is the need to seal vapor barrier materials adjacent to vertical structures.

5. Other applications.

A vapor barrier is also needed when insulating basements and balconies (areas in contact with cold external surfaces. For basement and underground areas, membrane films are considered the best, the walls and ceiling of the basement must breathe, the floors are insulated from the ground side. For installation of vapor barrier when insulating balconies and loggias, preference is given to polyethylene foam with the reflective side directed into the apartment.This is almost the only case when materials are placed end-to-end rather than overlapping, but sealing of adjacent areas is still required.

Possible mistakes

In addition to choosing the wrong side, technology violations include:

1. Lack of overlaps or insufficient insulation of joints.

2. Pulling on thin films, especially on structures subject to temperature extremes, this leads to their rupture. But excessive sagging is also not required.

3. Absence of ventilation gaps for evaporation of condensate from the vapor-tight side of the film (a vivid example of an error is the installation of the inner cladding directly on the bottom layer of the roofing cake).

Before laying the vapor barrier, you should calculate the required amount. The use of different types is undesirable, although there are no clear standards in this case. A common mistake is to buy rolls strictly according to the area of the working surfaces without a 15% margin of overlaps and trivial damage.

There is only one option when it is not necessary to put a vapor barrier - when building a house from a wooden beam, but this exception does not apply to absorbent insulation materials and floors, they always need protection. Work is carried out in a warm and, if possible, dry season, the films are in every possible way protected from getting wet. An important condition is the tight adhesion of the vapor barrier to the insulation (ventilation gaps remain on the outer, reflective and impermeable side), voids and sagging are unacceptable. All surfaces must be clean, grease-free and dry.

In case of doubt about the correctness of the decision on which side of the vapor barrier is laid to the insulation, you should read the instructions again. Reflective and rough planes are easily identified, with membranes more difficult. Usually the side facing down when unrolling the roll is considered to be the inside side. Experts advise paying attention to the coloring: lighter shades are observed at the sides adjacent to the insulation. But there is a variety in which it is precisely the matte (most often fabric) surface that is vapor-proof. If this is not enough to reveal the desired properties, then the canvas or film rolls a little on the floor, the tight-fitting side of the material will be the inner one.

When building a country house or a private bath, thermal insulation of various surfaces is an important step. In addition, the insulation itself needs high-quality and reliable vapor barrier protection. To prevent the negative effects of external factors and the formation of condensation on the insulator, any homeowner should have a general idea of how to properly install the vapor barrier in order to ensure a long service life of the entire structure.

Membrane structure and principle of operation

The most popular in terms of their performance characteristics are breathable multilayer membranes, which are designed to create reliable vapor barrier protection.

They consist of three layers, each of which has an important function. The first layer prevents the penetration of steam into the insulation, the second provides the necessary strength of the base, the third protects against moisture from the outside.

Each individual layer has the necessary perforation for good air exchange. The first layer removes excess moisture, ensuring the penetration of dried air. The reinforcing layer keeps warm air masses inside thanks to the special weaving of the threads. The third layer provides sufficient traction within the structure.

Some types of membranes have an additional anti-condensation layer on a viscose or cellulose basis. It retains excess moisture deposited on the paper fibers. For the natural removal of moisture from the membrane, a technological gap of 2.5 cm is provided between the vapor barrier and the surface finish.

Features of installation of vapor barrier

An important stage in the protection of insulating materials is the laying of a reliable vapor barrier layer. All work is carried out in the process of repair or reconstruction of the finished building, or during the construction of a new structure. In order to properly install the vapor barrier, it is necessary to understand how to connect the membrane sheets and which side to fix them to the insulating base.

Preparatory work

At this stage, work is being carried out to select a suitable type of vapor barrier, taking into account the peculiarities of the installation process, operational characteristics and material requirements.

Before laying the vapor barrier, careful preparation of the surfaces is required. Here it is important to consider the type of material used in the construction of floors, walls, ceilings and roofing structures.

During the construction of a log house, all structural elements are treated with protective antiseptics and fire retardants.
When carrying out repair and reconstruction work, a complete dismantling of the finishing, cleaning and preparation of surfaces is carried out:

Wooden elements are treated with anti-aging, rotting and burning compounds. Concrete, block and brick surfaces are treated with deep penetration antiseptic compounds.

Proper surface preparation will ensure a long service life of the insulating material and the entire structure.

Ceiling vapor barrier installation technology

If the roof structure and floor slab are made of wood, then the installation of the waterproofing membrane is carried out on a prepared base.

A roll or block insulation is mounted in the space between the rafters and the joists, the best option is mineral or basalt wool. Next, you can lay the vapor barrier on the ceiling surface.

When the thickness of the insulation is equal to the height of the log, a counter-lath is additionally installed to maintain natural ventilation.

It is necessary to mount the vapor barrier on the ceiling with a slight overlap on the walls around the perimeter, with special attention to be paid to the corners. It is better to place joints on logs and glue on both sides with tape on a reinforced base.

Important! When installing the vapor barrier, sagging and deformation of the canvases should be avoided.

For thermal insulation of a flat roof or concrete ceiling, a waterproofing film is mounted on a self-adhesive tape from the inside, then a lathing made of wood or metal is installed.

The height of the battens is determined based on the thickness of the thermal insulation material and the minimum technological gap for ventilation. The installation step is 3 cm narrower than the width of the heat insulator, which makes it possible to ensure high-quality laying of the insulator into the prepared crate cells.

Vapor barrier laying technology on the floor

The scheme for installing vapor barrier protection on the floor is similar to how the material is laid on wall and ceiling surfaces.

The wooden floor is insulated along the logs, on which the waterproofing is laid. Further, a heater is placed in the space between them - cotton wool on a mineral or basalt basis. After that, the vapor barrier material is laid.

The roll material must be laid with an overlap of 12 cm with careful gluing of the joints with metallized tape on both sides. A correctly laid vapor barrier should completely cover the floor surface with an overlap of up to 10 cm on the walls.

To equip a vapor barrier on a concrete base, it will be necessary to install a crate, in the cells of which a waterproofing layer and a heat insulator will be laid.

Choosing a side for mounting a vapor barrier

After the material for the vapor barrier has been selected, an important question should be considered - which side to attach the vapor barrier to the insulation. Such materials can be recorded as follows:

Polyethylene films (reinforced and simple) are laid on either side, which does not impair the protective properties of the material.
Foil films are installed with the reflective side inside the room to effectively reflect heat.
Anti-condensation films are mounted with a fabric surface inside the room, treated - to a heat-insulating base.
Membranes of any type are attached with a smooth surface to the heat insulator, and a rough surface - inside the room.
Foam-based insulators are laid in the same way as membrane materials.

Important! Before laying the vapor barrier to the insulation, it is recommended to spread the prepared material on a flat surface to correctly determine the inner and outer sides.

The face or the wrong side of the vapor barrier?

If a breathable membrane is used to create a protective barrier, the main thing is to determine which side to put the vapor barrier - face or wrong side.

The vapor barrier cake must be laid so that the protection is directed to the heat insulator from both sides with the smooth seamy side, and the rough front side - inside the room.

The rough surface provides protection against moisture penetration to the insulation, while the smooth surface contributes to maximum heat accumulation.

Determination of the inlet width when installing the membrane

Along the edge of the insulating membrane, there is a special marking to determine the width of the overlap of the sheets, which ranges from 8 to 20 cm.

The vapor barrier strips on the roof should be laid in a horizontal plane, from bottom to top, overlapping each other with a width of 15 cm.In the ridge, the overlap is 18 cm, in the valley - 25 cm.

On walls, ceilings and floors, the canvases are mounted with an overlap of 10-15 cm.

Is a ventilation spacer required?

There is a 5 cm ventilation gap at the bottom of the membrane vapor barrier to prevent condensation from forming on surfaces and on the heat insulator.

Diffusion membranes can be mounted on insulation, plywood or OSB. In a membrane with an anti-condensation layer, gaps up to 6 cm wide are located on both sides.

To create a gap for ventilation when insulating the roofing structure, a counter-lattice is used. In the process of fastening a ventilated facade, a technological gap is created during the installation of racks located perpendicular to the vapor barrier.

Elements for fastening the vapor barrier

To securely fasten the membrane or film vapor barrier, wide-headed nails or metal construction brackets are used. The most practical option for fastening is counter-rails.

To increase the tightness of the structure, individual elements of the vapor barrier are additionally glued with double-sided adhesive tape or wide metallized tape.

To ensure a long service life of modern heaters, you will need high-quality vapor barrier protection. Otherwise, it will be difficult to obtain the optimal ratio of temperature and humidity indicators in the premises. The main thing in this matter is to choose the right material and know how and which side to lay to the heat insulator.

A fairly common problem after warming a house is the lack of the expected effect of the work performed. It would seem that a traditional material was chosen, for example, mineral wool, everything is done according to building laws and canons, but it is still cold inside the room. The reason for this may be the lack of knowledge of the "experts" of elementary norms, including which side to put the vapor barrier to the insulation. Let's take a closer look at this issue.

Vapor barrier is divided into two types according to the method of application:

liquid paint vapor barrier;
vapor barrier membranes (film).

The paint vapor barrier is applied with brushes and rollers in places where roll vapor barrier is difficult to apply, for example, on ventilation and chimneys. This family of vapor barriers is represented by materials such as bitumen, tar and tar.

Vapor barrier membranes

First of all, let's decide on the types of vapor barrier films for their purpose. In terms of their specifics, membranes used in construction are offered in the following design:

membranes with vapor barrier properties;
the membranes are vapor-permeable.

To protect the mineral wool from the effects of moisture on it from the inside, it is necessary to additionally lay a layer of vapor barrier. When insulating the roof, floor or interior of a house located directly below it, it is recommended to use an appropriate film. Note that the insulating layer is laid from below, under the laid mineral wool (from the side of the room).

In cases where external wall protection is performed, the corresponding components should not have perforations or pores.

Always pay attention to the value of the vapor permeability coefficient, the lower it is, the better for you. Plain plastic wrap is a great option. An ideal choice would be a material with additional reinforcement. The presence of a foil-clad aluminum coating is considered only a plus.

Do not forget that the presence of a vapor barrier finish leads to a multiple increase in humidity in the insulated space, so you should take care of a good ventilation system in advance.

Polyethylene reinforced film

Existing special vapor barrier films are made with an antioxidant coating. Due to it, moisture does not accumulate. Typically, they are attached to components that are sensitive to rust formation. We are talking about metal tiles, corrugated board, galvanizing, etc. The rough fabric layer on the wrong side of the film ensures effective moisture removal. It is laid with the processed side to the insulation, and the fabric side to the outside, so that a distance of 20-60 mm remains to the mineral wool.

https://youtu.be/xTWpLwH8-QI

Video # 1. IZOSPAN vapor barrier laying technology

When insulating the walls of the house from the outside, a building membrane is used that can evaporate, protect the material from strong wind gusts. In addition, it is suitable for protecting pitched roofs, façades with a leaking base from moisture. Often, a vapor barrier film has very small pores and surface perforations, due to which water is effectively removed from the insulation into the ventilation ducts. The process is the better, the more actively the removal of vapors takes place. This will allow the insulation to dry out quickly and efficiently.

There are the following types of vapor-permeable films:

Pseudo diffusion membranes, which transmit no more than 300 grams / m2 of vapor for 24 hours.
Diffusion membranes with a vapor permeability coefficient in the range of 300-1000 grams / m2.
Super diffusion membranes, with an evaporation rate of more than 1000 grams / m2.

Since the first type of insulation is considered to be good moisture protection, it is more often placed under the roof surface as an outer layer. Additionally, you will need to provide an air gap between the insulating layer and the film. At the same time, the specified component is not suitable for facade processing, since it conducts steam rather poorly. This is due to the penetration of dust and other debris into the pores of the membrane during dry time, the "breathing" effect disappears and condensation begins to accumulate on the surface of the insulating material.

Superdiffusion membrane IZODACH 115

The two remaining types of membranes have large pores, this eliminates the possibility of their clogging, due to which there is no need to leave an air ventilation gap in the lower part. As a result, it is not necessary to mount the crate and counter battens.

Three-dimensional diffusion films are commercially available. A ventilation layer is already provided inside the membranes, due to which moisture cannot reach metal surfaces. The specificity of the film device is similar to the antioxidant variant. The only difference is in the removal of moisture from the insulation. This is beneficial, since when the roof is tilted even at a slight angle of 3-15 degrees, the possibility of condensate draining through the bottom is excluded. Therefore, corrosion of the galvanized coating will gradually occur, followed by its final destruction.

Which side to fasten the vapor barrier to the insulation

First you need to figure out where you may need to lay the vapor barrier membrane, and then decide on the side of the vapor barrier.

If the insulation is laid from the front part of the wall, then the vapor barrier film is fixed from the outside, this will be waterproofing.
Ceiling and roofing requires the use of an antioxidant vapor barrier. Bulk and diffusion coatings are often used. They are laid on top of the mineral wool according to the principle of ventilation facade organization.
In the absence of additional insulation of the roof and ceiling, the vapor barrier film is attached to the underside of the rafters.
Thermal insulation of the upper part of the ceiling of the rooms, the ceiling located under the attic space, requires laying a vapor barrier membrane on the lower side of the insulation.
When insulating walls and floors from the inside, it is recommended to additionally lay a vapor barrier film on the outside of the mineral wool.

Many "experienced" builders even have no idea how the vapor barrier membrane should be attached to the walls: the front or the wrong side.

The best solution would be to use material with the same seamy side and front side.

And what to do in the case of a one-sided option, in particular with antioxidant insulator? You need to know that the seamy side is the fabric surface located during laying in the interior of the room.

Determination of the side of laying the vapor barrier

A metal plane turns in the same direction foil membrane- the shiny side to the inside of the room.

For any film vapor barrier materials the following rule applies: the smooth side is laid to the insulation, while the rough side should be facing the room.

The same rule applies to polypropylene steam insulators, which are laid with the smooth side to the insulation.

The vapor barrier is laid with the dark side to the insulation

It must be borne in mind that when the roll is rolled, for example, on the floor, the inner side must be on the floor.

In addition, most often the darker side is the outside.

Does the membrane need an air gap?

You should always leave it. A special gap up to 50 mm wide is arranged on the underside of the films. This will avoid condensation on walls, floors and insulation. It is important to avoid contact of the surface cladding with the membrane. By using diffusion film for floors, walls or ceilings, you save yourself many problems, since you can fix it directly on a heat insulator, OSB or moisture-resistant plywood. A ventilation spacer is required on the outside of the membrane. In the version with an antioxidant component, the air gap should be within 40-60 mm on both sides.

Organization of a ventilation gap when laying a vapor barrier

While everything is clear with the walls and floor, the situation with the roof and ceiling is kept apart. When performing a ventilation gap, additional installation of a counter-lattice based on wooden bars will be required. When organizing a ventilated facade, a gap is left when erecting horizontal profiles and racks located perpendicular to the wall and the film.

Video number 2. Vapor barrier installation technology ONDUTIS

How the vapor barrier is attached

Fixing the membrane to walls, floors or ceilings can be done using wide-headed nails or a construction stapler. However, the best choice would be to use counter rails.

The vapor barrier is laid with an overlap with an overlap of at least 10 cm. After fixing the vapor barrier, the joints are glued with a special tape or tape for vapor barrier.

Conclusion

In conclusion, we will say that membranes will allow any building structure to serve an extremely long time. Alas, it is impossible to achieve a positive ratio of moisture and temperature in other ways. In addition, do not forget about the rules for laying vapor barrier. Most manufacturers also distribute assembly instructions with the product. This is especially true for diffusion and superdiffusion membranes. Therefore, do not be lazy before purchasing to clarify all your questions with a sales assistant.

Warming is a very important stage in the construction or renovation of a house, which determines whether you will be comfortable in it. Incorrect performance of this "procedure" can lead to unpleasant consequences, for example, condensation, increased humidity in the air. But this will not happen if you take care of the vapor barrier and lay it with the right side to the insulation.

Peculiarities

When insulating a house, you should carefully follow the correct sequence of actions and use only the best materials. Unfortunately, often the owners who undertake to insulate their home on their own forget about one very important aspect - the vapor barrier. They install only insulation and do not even think that it is in contact with too warm or too cold air inside the room, and that soon condensation in the form of water droplets will begin to form on it.

And this not only does not contribute to insulation, but also spoils the material itself - it moistens it, and if the steam still does not have time to evaporate, mold appears, and the construction of the insulation deteriorates. Moreover, taking into account our climatic conditions, a similar situation occurs at least four times a year - when the seasons change and, accordingly, the temperature in the room and outside it "conflicts", and it is the insulation that becomes the battlefield.

That is why an important stage of insulation is the fastening of the "vapor barrier". The vapor barrier becomes an impenetrable obstacle for steam, prevents it from turning into water, as it “closes” it inside the room and does not allow contact with excessively warm or excessively cold air.

Materials (edit)

Vapor barrier can be done with several materials. From this set, three main types should be distinguished.

Film. A deaf vapor barrier that does not allow water vapor to pass through. One of the main advantages is the low price. As a rule, it is made from polyethylene or butylene, their derivatives. Two-layer steam condensate films with a smooth inner and rough outer surface. Lingering on the outside, the condensation drops do not flow down, but evaporate over time. In the case of a deaf vapor barrier, you also need to take care of the air gap in order to avoid the greenhouse effect, but more on that later.
Diffusion membrane... The main difference from the film is that the membrane passes part of the vapor through itself - but only that optimal amount that does not stay inside and instantly evaporates. Therefore, the vapor permeability of membranes is usually referred to as limited. The diffusion membrane is made of polymer film and polypropylene and has two sides.
Reflective or energy saving film. The outer layer of such a film is metallized, which allows it to withstand high temperatures. Therefore, it is most often used in baths or saunas, reflecting part of the infrared radiation.

As you know, for the insulation of houses in modern conditions, materials such as mineral wool, expanded polystyrene, ecowool are used. Vapor barrier is also needed in the case of mineral wool insulation.

In fact, a vapor barrier is always needed, regardless of how expensive or high-quality insulation material you use. Mineral wool or mineral wool is otherwise the cheapest material, but its level of thermal conductivity is low, which reduces the likelihood of heat loss in the room. Rodents, mold, fungus do not like minvata, it has high noise insulation and is easy to install. But it still requires a vapor barrier for itself.

The most commonly used vapor-permeable limited diffusion membrane. It is laid against the walls, after which it is necessary to lay mineral wool, and in symbiosis they allow the walls of the house to "breathe".

The question of vapor barrier also arises when the house is insulated with ecowool. In general, ecowool is loose cellulose fibers that have the ability to absorb warm moisture and at the same time remain dry. Fungus, mold do not start on it, the air in it simply does not get wet (if the humidity changes do not exceed 25% percent). From all of the above, it follows that just in the case of ecowool, the vapor barrier can be left unattached.

Another popular insulation - expanded polystyrene actually has another more easily called foam. It lays down both on external surfaces and on internal ones, and in the case of external insulation of loggias, balconies or attic floors, it does not require vapor barrier - it itself does a good job of keeping the insulation technology up to date. But if you insulate the interior with foam, vapor barrier and waterproofing are required in order to avoid the formation of fungus, mold and wet walls.

Device

Acquiring a set of quality materials is only a third of the success. In fact, these materials need to be correctly installed, arranged in the correct sequence. For this, you should find out which side of the vapor barrier is laid, how it is fixed, in what order and what to nail before - a vapor barrier or insulation.

First you need to carry out the preparatory work. At this stage, the type of coating that you will insulate, its performance characteristics and requirements for the material of the insulation and vapor barrier are identified.

So, the surface must be carefully prepared. This takes into account the type of material from which it is made. Wooden elements must be treated with anti-aging, rotting and burning compounds. In the case of concrete and brick, deep penetration antiseptic compounds are used. Half of the success in its operation depends on the correct surface treatment.

If you are carrying out repairs or reconstruction, then pay attention to the fact that before insulation, all traces of the previous finish must be removed, a complete cleaning must be done. And if we are talking about a log house, then all elements must be treated with fire retardants and antiseptics.

Ceiling vapor barrier

In the case of roof structures and interfloor floors, the installation of a vapor barrier is supposed to be on a prepared and properly processed surface. It is best to use a diffusion membrane here.

The main difference between laying a vapor barrier on the ceiling and laying it on other surfaces is that in this case, the insulation is first laid, and only then the membrane. It can be mineral or basalt wool in blocks or rolls. It is mounted between the joists and the rafters. If the thickness of the insulation is equal to the height of the lag, you will have to additionally perform a slatted counter-lattice so that the ceiling is ventilated. After all this, you can do the vapor barrier.

It should sink a little on the walls around the perimeter, the joints should be fixed on the logs - to ensure that moisture does not get into the space between the membrane and the insulation. Pay special attention to the corners - these are problem areas, it is better to glue them additionally. Use a reinforced tape or a construction stapler as a retainer.

In the case of insulating a flat roof or concrete ceiling from the inside, you can also use a conventional vapor barrier film. It is attached to the self-adhesive tape also after the insulation, and then the crate is installed - metal or wooden.

Floor vapor barrier

In the case of laying the vapor barrier on a wooden floor, an additional waterproofing should be installed. The floor is also insulated along the logs. Mineral wool or cotton wool on a basalt basis is installed in the space between the lags. Further, without any additional work, the vapor barrier is laid.

If we are talking about a roll-on vapor barrier, but it fits with an overlap of 12-15 cm with the most careful gluing of joints, gaps and cracks on both sides with metallized tape. As in the case of ceiling insulation, the overlap on the walls should be within 10 cm.

For a concrete floor, you will need a crate. You will need to lay a waterproofing layer in the crate cells, on top - a heat insulator, and after the mineral wool the third layer is a vapor barrier.

Vapor barrier on walls

The process of warming and vapor barrier walls is a little more complicated than performing the same work on the ceiling or floor and implies a slightly larger number of stages. Consider the process of laying a vapor barrier film on the walls.

First of all, a frame is mounted from small-section bars. The size of the lathing is determined by the width of the heat insulator block - the distance between the cells is equal to the width of one slab. Mineral wool is classically used.

At this stage, you should pay special attention to possible gaps arising from the difference in the width of the insulation, frame and vapor barrier. The slots are sealed with reinforced tape, and the sheets of film are glued horizontally with an overlap of 15 cm.

Subtleties of installation

When installing a vapor barrier, you should pay special attention to important issues.

Which side to install the vapor barrier?

Very often, masters find it difficult to answer this question, but everything is not so difficult. Ordinary film has the same front and back sides - and then it doesn't matter which side to lay it on. But in the case of one-sided films, the situation is a little more complicated.

For example, antioxidant films have the wrong side of fabric, and according to installation requirements, it must look inside the room. Steam condensate films must be laid with the smooth side to the insulation, and the rough side outward. But with diffusion films, you should look directly at the instructions, since such films can be either one-sided or double-sided. Energy-saving films are laid with the foil side, on the contrary, outward - after all, they should reflect, not absorb, heat. The same goes for metal coatings.

How to distinguish the outside from the inside?

This information should be indicated in the instructions or on the manufacturer's website, you can ask a consultant or master about this. However, if none of the above is right for you, you will have to learn how to determine the sides of the vapor barrier yourself.

So, remember: if the vapor barrier has two-color sides, then the light side will always fit into the insulation.

But also pay attention to how the roll of the vapor barrier rolls out - the side that faces the floor will be internal, and it should be placed against the insulation. In the case of a vapor barrier with a different surface, a smooth layer will always be internal, and a fleecy or rough layer will always be external.

What kind of fasteners should you use?

This can be either a regular construction stapler or nails with a wide head, but counter-rails are considered the best option.

Is an air gap necessary near the membrane?

It is believed that this is a mandatory moment - it is categorically impossible that the wall is in close contact with the membrane, you should leave a ventilation gap of about five centimeters. Condensation will not build up in this way. In the case of a diffusion vapor barrier, the air gap is made with the outer side, and the film itself is laid directly on the insulation.

Do I need to glue the joints?

It is also necessary - the individual parts of the vapor barrier should be hermetically connected to each other without the formation of gaps, the same applies to the places where the vapor barrier is attached to windows or doors. For this, self-adhesive tapes are used - double-sided or single-sided, - as a rule, made of polyethylene or butylene, propylene. These tapes not only perfectly hold the membranes together, but are also used in their repair - they can be used to seal holes and crevices.

In no case do not use tape for this, it is better to contact a sales consultant in a building materials store or go to the website of the company from which you purchased the vapor barrier - as a rule, companies produce materials for the repair of their products.

The main purpose of vapor barrier is to prevent water pores from leaving the room through insulation and surfaces. This means that the vapors, one way or another, remain in the room, and in order for the humidity to not rise and the microclimate is not disturbed, it is necessary to carry out natural or forced ventilation in time.

If you are interested in the question of how to overlap in case of overlap of membrane parts, we advise you to pay attention to the films themselves. There are markings along their edge - it speaks about how exactly the overlap of the film should be. Depending on the type and company, the value indicated there is not less than 10 cm and not more than 20.

And also pay attention to the angle of the roof slope. If it is less than 30 degrees, the overlap cannot be more than 10 cm. If it is less than 20 degrees, the overlap cannot be less than 20 cm.

For the installation of the vapor barrier of the roof and on which side to lay the vapor barrier to the insulation, see the next video.

When arranging protective layers of insulation, the use of vapor barriers is necessary in any case. The range of products is large, it is difficult to understand the purpose, scope, characteristics. In addition, you should know which type of materials is suitable for a wooden base, and which type is needed for concrete floor slabs. Let's consider the questions in more detail, we will figure out how the vapor barrier is installed on the ceiling and whether it is possible to do the work with your own hands.

If the room is located so that one side of the ceiling is constantly warm, and the second plane faces outward, where the temperature drops to minus indicators, for example, a room under an unheated attic, a roof, then condensation will collect in a certain area of the structure. This area is called the dew point and it is important to bring this point outside the insulation layers. Otherwise, ceilings, supporting structures and thermal insulation will begin to get wet, rot and become unusable after a short time.

The vapor barrier material protects the main structural units, floors, load-bearing beams from damage, prevents rotting, and increases the energy efficiency of the house. A properly laid layer of insulator will release moisture outside, but will not let it back in - this is due to the special structure of the material.

Advice! In rooms with variable humidity, laying a vapor barrier is a prerequisite. The suspension of water rises upward, it is necessary to ensure the timely removal of steam so that mold does not form in the room.

Varieties of vapor barrier materials

The range of products is great:

Reinforced polyethylene films. They differ in zero moisture absorption, do well with protective functions. For areas of high humidity, it is better to use perforated films, and for rooms with a normal level of moisture, non-perforated products are suitable. The availability and versatility of the material are pluses, and the ability to collect condensate on the surface is a minus.
Polypropylene tapes viscose-coated - an option that is suitable for all types of premises. Viscose absorbs moisture without forming condensation. Increased strength and ease of installation are pluses, the high cost of the material can become a minus.
Foil coated insulation represents foamed polyethylene or thick cardboard covered with foil (on one or both sides). High quality, reliability, durability and the ability to display heat are advantages. In addition, the products are notable for their small thickness and are shown for installation in baths, saunas.
Vapor barrier membranes. Modern material with several layers: perforated fabric, plastic film, polypropylene. The main quality is 100% vapor barrier. The membrane collects all moisture without giving it back. Particularly effective are 2-sided insulators, which successfully remove all moisture to the outside. For the treatment of concrete surfaces, varnishes and mastics with a membrane effect are offered.
Glassine is a durable cardboard impregnated with bitumen. Differs in plasticity, light weight and is used to protect wooden buildings.

When choosing a vapor barrier, you should pay attention not only to the cost of the material, but also to the purpose, scope, protective characteristics and base materials for which the product is best suited.

The principle of operation of vapor barrier products

Regardless of the type of product, all insulation has one purpose - to prevent the accumulation of condensation on the insulating materials. But according to the principle of operation, the products differ. For example, the film does not allow moisture to enter the insulation, and the membrane allows steam to pass into the layers of thermal insulation, helping to evaporate excess moisture. And this is the main difference.

Important! When purchasing membrane sheets, you need to know how to properly lay a vapor barrier on the ceiling - unlike film products, membrane rolls, mounted incorrectly, will give moisture inside, not letting it out.

What materials are better to choose

The type of insulation is selected depending on the base material, the level of humidity in the room, the evenness of the base ceiling and many other factors.

For wooden ceilings

Basic requirements: to create protection of wood from moisture and to ensure ventilation of the structure and the "insulation cake".

Suitable:

polyethylene, polypropylene films;
foil type insulators;
glassine;
membrane vapor barriers.

To eliminate condensation on the films, it is necessary to provide ventilation gaps - so the moisture will gradually evaporate without damaging the timber structures.

For concrete ceilings

You should choose products that are attached directly to the base base: varnishes, mastics, paints, insulators with a foil layer. The latter are mounted both on floor slabs and on a wooden frame - this is convenient for the formation of a hemmed, suspended ceiling.

Features of the technology of installation and fastening of the vapor barrier

Before starting work, the ceiling is cleaned of old coating, dirt and dust. Then this: if roll materials are used, the surface must be putty, eliminating defects, irregularities, sealing cracks, but before coating with liquid paints and varnishes, bituminous materials, it is enough to level the concrete floor slabs with a ready-made repair compound. After filling and leveling, the base surface is primed in 2-3 layers with preliminary drying of the previous layer before applying the next one.

On a note! The wooden ceiling must be treated with an antiseptic, fireproof impregnation, and only then primed.

On a wooden ceiling base

Roll sheets are attached to the prepared base base with a stapler on staples. When laying out film products, in order not to deform the sheets, it is better to put small pieces of cardboard, thick paper under the bracket.

Lay the strips overlapping each other by about 15-20 cm, glue the joints with construction reinforced tape. In the areas of the joint with the walls, the film is not cut off, but falls by 10-25 cm onto the wall panel.

Important! When using a vapor barrier, first consider the material and determine which side to lay the vapor barrier on the ceiling. Layout with the smooth side to the ceiling, and a rough surface "turned" into the room.

After the installation of the insulation, a crate is formed so that the sheets are held tighter, in addition, the structure will create the necessary ventilation gap so that drops do not collect on the vapor barrier of the ceiling, and will serve as the basis for finishing the ceiling. Fasten the crate with self-tapping screws, hemming to the base base.

On concrete ceiling bases

Preliminary preparation of the concrete slabs will reduce the risk of the thermal insulation layers getting wet. Most often, the sheets are moistened due to cracks at the junction of the slabs, so it is important to properly seal all the seams, inspect the areas of connection between the ceiling and the walls - putty and prime the surface.

Once the base is dry, vapor barrier materials can be applied. Polymer mastic is considered a good solution - the mixture protects well from moisture vapors, and also does not let water through from above if there is a gap somewhere in the floors. Mastic is applied according to the instructions from the manufacturer, all information is written on the packaging, it should be carefully studied.

When using roll, sheet materials, a crate is formed from a wooden bar or a metal profile on the base. The size of the cells must correspond to the size of the insulation sheets. Many craftsmen prefer to measure not vapor barrier materials, but insulation - first, insulation elements are laid out in the cells, and then a membrane or film.

How to fix the vapor barrier to the ceiling:

on a wooden crate with staples (a construction stapler is useful);
on a metal structure with scotch tape.

On a note! Foil materials are laid out only end-to-end, membrane and film with sheets overlapping each other by 15-20 cm. However, in both cases, the seams are fixed with tape.

After the installation of the vapor barrier of the ceiling has been completed, the sheets are pressed with another frame of the sheathing so that the necessary ventilation gap remains. If then the ceiling is tightened with a stretching canvas, then it is permissible to take thin dies to form the second frame of the lathing, so as not to make the entire structure heavier. And in the case of the formation of a false ceiling or hemming the surface with plywood, gypsum board, the timber must be strong enough, otherwise the hemmed ceiling will collapse.

Why condensation appears on the vapor barrier

Having figured out how to properly lay the vapor barrier on the ceiling, many owners still face the formation of drops on the surface of materials.

There are several reasons:

Sheets of foil products are stacked overlapping one another. This is not true. The lack of clearance and ventilation leads to the accumulation of moisture on the surface of the insulator.
Wrong product selection. In rooms with high humidity, film insulators will collect all moisture on the surface, which will then flow down. To avoid the phenomenon, replace the usual film with materials with a viscose layer - this will eliminate the appearance of condensation.

And the main mistake is that the vapor barrier membrane is laid out on the wrong side. Recall: the smooth side is turned to the ceiling surface (rough ceiling), and the rough one "looks" into the room. Afraid of making a mistake, take a 2-sided foil insulator, in addition to moisture protection, the products have the property of retaining heat, which is an additional advantage of the insulator.

When building a house, one of the main tasks is to provide reliable protection of the building from interaction with water, which has a destructive effect on any building material. Steam and moisture are other factors affecting materials negatively. If you do not think about how to protect structural elements from them, then such frivolity can lead to the appearance of mold and mildew. To avoid this, when building houses, a vapor barrier layer is laid.

Why do you need a vapor barrier?

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

During their operation, steam is constantly formed in them, which must somehow leave the room. Therefore, it settles on the walls and ceiling. With prolonged exposure to steam on these surfaces, the destruction of building structures occurs, which negatively affects the state of the structure as a whole. To prevent this from happening, a vapor barrier is being installed. With her help protects walls and ceilings from steam penetration.

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

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

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

In some cases, you simply cannot do without a vapor barrier, the installation of which should be performed correctly:

Materials used for vapor barrier

The term vapor barrier should not be taken as a vapor barrier. Membrane materials, which are currently used in the implementation of work on protection from steam, ensure the passage of air in a minimum amount, which completely eliminates the possibility of a greenhouse effect. Excess moisture is retained in the membrane, and the air freed from moisture is not able to damage the wall structure or reduce the performance of the insulator. The materials for protection from steam have an inner "coat" that ensures the redirection of moist air along the desired path through the ventilation system.

Types of vapor barrier materials:

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

Common brands of membrane materials

At the moment, vapor barrier materials are presented in a wide range. Moreover, each of them is intended for a specific area of use.

Vapor-proof materials installed outside

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

When using them, it is extremely important to ensure tight membrane fit to the insulation. Therefore, during work, these materials should be securely fixed. There should be no slack or loose areas. Otherwise, with strong winds, rare gusts will occur.

Indoor installation materials

When the task is to perform vapor barrier of walls, ceiling from the inside of a wooden house, then use "Megaizol V". By itself, it is a polypropylene film, which consists of two layers. There is an anti-condensation surface on the outside of this material. The use of this material in winter provides it with protection from phenomena such as condensation and fungus. In addition, its use excludes the destruction of elements of wall structures. Also, this material protects the room from the ingress of insulation particles. The same function is inherent in Izospan V.

Materials for waterproofing and vapor barrier with a reflective layer

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

Vapor barrier rules for frame walls

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

If ecowool or foam is used in frame structures as insulation, and an effective ventilation system is arranged in the house itself, then you can refuse a vapor barrier device. If the owner of the building has decided to provide protection from steam, then in this case you can use one of the following schemes:

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

Vapor barrier of the walls of a wooden house

The walls of a wooden house should have a higher vapor resistance in comparison with brick buildings. When choosing membrane materials for surface insulation in wooden buildings, one should proceed from the thickness of the timber, the tightness of the grooves, the presence of cracks in the material of the walls.

Glued laminated timber is a popular material for the construction of wooden houses. In the process of its manufacture, wood is dried in special chambers. As a result, a low level of moisture in the finished material is ensured. It has grooves for a seal. The material is characterized by low shrinkage, therefore, it enters the insulation in a limited amount.

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

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

Conclusion

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