Vapor barrier is the general name for a whole package of methods for protecting thermal insulation or building materials from the appearance of steam inside them and the release of condensate. This type of insulation allows you to withstand absolutely any temperature conditions, and therefore vapor barrier is considered an important link in preserving heat inside a building during the winter season. A well-designed vapor barrier prevents destruction insulation materials and thus contributes to the durability of the entire structure. So, vapor barrier - how to install it correctly.

Vapor barrier materials

Vapor barrier, as a method of preserving heat, is needed to ensure that the moist steam created in the room does not cause the appearance of fungus, mold, does not have a destructive effect on the ceiling structures, roof, walls, floor and freely penetrates outside. There are many materials that provide stable vapor barrier: film, penofol, membranes and others. Let's take a closer look at each of them.

Still the most common material is film. It must be tensioned well during installation, and also remember to make gaps for ventilation.

Membranes represent a modern construction material, which can be used not only as a vapor barrier, but also for waterproofing premises. There are several types of membranes: single-sided and double-sided, single-layer and multi-layer. Double-sided membranes are perhaps the most economical option, they are often used for roof vapor barrier.

Another type that needs to be mentioned is reflective vapor barrier. Often such insulators are used in baths and saunas. Penofol is one of the materials in this group, which is foamed polyethylene. Can also be used as a lightweight thermal insulator. The next common reflective vapor barrier is foil on kraft paper. It can be used in almost any room, even at elevated temperatures.

Which side should the vapor barrier be laid against the insulation?

This is probably the most frequently asked question - which side to lay the vapor barrier against the insulation, so it was highlighted as a separate item.

The vapor barrier film has a two-layer structure. One side is smooth, the other has a rough surface to retain drops of condensation and its subsequent evaporation. This film is laid with the smooth side outward (adjacent to the insulation), and the rough side into the room.

Reflective (foil) vapor barrier is created not only to protect the insulation, walls or roof, but also to return heat to the room thanks to the reflective surface. Therefore, to perform this function, it must be placed with the reflective side in the room.

An air-permeable vapor barrier membrane protects walls and roofs from moisture, but at the same time allows the structure to “breathe”. The membrane can be either double-sided, with the same characteristics on both sides, so it can be laid on either side, or one-sided, in this case, manufacturers indicate the reverse side on the surface of the material. When purchasing, you must read the installation rules.

How to properly install a vapor barrier

Once we have decided which side to lay the vapor barrier against the insulation, we can proceed directly to work. Let's describe the process using film as an example:

• First we lay thermal insulation and sound insulation, after which we can lay the film;
• the film should not be sagging, so stretch it well during installation;
• The film is secured with double-sided adhesive tape or tape. You can also use nails with a wide head for fastening, driven in increments of 30 cm or furniture stapler, which can make your work much easier. You can also use wooden slats, which are screwed with the same frequency of 30 cm;
• The sheets of material must be laid with an overlap (10–15 cm), while specifically for the film (as it does not allow air to pass through), do not forget to make gaps for ventilation from time to time, about 5 cm wide.

Now you can find others, more modern options. For example, membranes with an adhesive side provided. You just need to delete protective layer and stick it on.

We have reviewed general rules How to properly install a vapor barrier, now let's describe the nuances for the roof and floor.

Roof vapor barrier

Protecting the walls of your home from moisture and steam is only half the battle. After all, the main part of the evaporation flows tends upward, and condensation cannot be avoided after heavy snow and rain, and it is the roof of the house that takes the first blow.

Among other things, poor roof vapor barrier leads to a decrease in indoor temperatures, unpleasant smell and dampness in the house, fungus, rust and other troubles. To protect your home from problems, you need a vapor barrier and it is very important to do it correctly.

Experts recommend using membrane materials for roofing that allow air to pass through, but do not allow moisture to pass through, thereby removing excess moisture from the roof insulation. Double-sided membranes can work on both the internal and external surfaces of the roof.

The sequence of laying the material is very important, you can see it in the photo below.

Floor vapor barrier

Floor vapor barrier plays an equally important role. Wet cleaning, showering, cooking and even normal breathing can affect the release of condensation. And the main flow of it settles on the floor.

If you are just building a house and not renovating, there will be less hassle. The first thing to do is process everything wooden elements floors with a special composition against rotting, insects and fungus. If you are making repairs, you must remove the old coating and thermal insulation. Check for sagging or rotten boards, if necessary, replace them completely or partially, and then also treat them with protective agents.

All previously listed materials can be used for vapor barrier of the floor. For the film, you should also make gaps for ventilation; other materials do not require this.
The most popular material is isospan. It should be noted that there is a difference between the ground floor floor and the interfloor ceiling. On the ground floor, waterproofing must be laid on the subfloor, followed by insulation and vapor barrier. On the second and subsequent floors we replace the waterproofing with a vapor barrier layer. You can see all this in the photo below.

Let's briefly describe the process for interfloor covering. We lay a vapor barrier on load-bearing frame floor, the canvas should overlap with a width of about 15 cm. We fasten it using any of the previously mentioned methods, but most often it is recommended to use a special duct tape. Next, the insulation is laid, after which another layer of vapor barrier is laid overlapping in the same way.

Vapor barrier along with waterproofing for the home - necessary thing. Protecting walls, roofs and floors preserves the material, its original form and properties, protects against the appearance of fungus, mold, drying out and rust, and also provides the home optimal temperature. And that’s all, we hope that this article was useful to you.

Installation of vapor barrier is required during construction residential buildings: the membrane protects the insulation from vapors emanating from the room into the under-roof space; on the other hand, the vapor barrier film prevents condensation from draining into the room. Incorrect installation of the membrane (on the wrong side) is fraught with the accumulation of an excessive amount of vapor inside the room, as well as uncontrolled access of moisture directly under the roof. The insulation will gradually become saturated with water and will cease to perform its functions, and the material of the sheathing and roofing will undergo intensive destruction.

Installing a vapor barrier under the roof

Which side to attach the vapor barrier

Special materials for vapor insulation are available in the form of single-layer films, foamed polyethylene with a metallized coating and two-layer membranes. Their installation has some differences, which is why it can be difficult to figure out which side to attach the vapor barrier to:

• The polypropylene film is installed with a rough surface to the under-roof space. This insulation texture will collect moisture, which will evaporate through ventilation gap. However, its size must be at least 20 mm. If the film is the most common (polyethylene), its sides will be identical.
• The two-layer membrane is laid with the smooth side facing the thermal insulation. For ease of use, manufacturers often apply special markings to the underside of the fabric.
• One-sided laminated polypropylene is also directed with a smooth surface towards the insulation.
• The foil side of the special films is turned towards the insulation.

Considering the variety of vapor barrier materials on construction market, difficult to compose comprehensive guide according to their installation. detailed information usually contained in the instructions provided by the manufacturers. But still, there are two more general rules:

1. If the instructions are unclear and the film is colored different colors, most light tone should be turned towards the insulation.
2. Many materials are rolled up so that the side that ends up at the bottom when it is rolled out can be immediately placed on the thermal insulation.

Main stages of installation

For pitched roof There is a certain sequence according to which a high-quality vapor barrier is installed. It is installed after laying the insulation, the surface of which should be free of defects. The beams for the sheathing are treated with antifungal compounds, after which a pre-calculated amount of film is prepared (covered area + 15%) and the following:

• construction stapler;
• special double-sided tape for insulating and fastening fabrics;
• construction/stationery knife;
• self-tapping screws;
• roulette;
• single-sided adhesive tape for joints, defects and crevices (from the same manufacturer);
• screwdriver;
• pencil;
• scissors.

On the rafters, between which are laid thermal insulation boards, fill the bottom part of the sheathing with two boards. Apply a strip of special tape with two adhesive sides. Cut the roll into sheets of appropriate length. Then, starting from the bottom of the sheathing, lay the membrane horizontally with the markings up on the insulation, slightly stretching the panel.

1. Attach the edges of the canvases to the rafters using a stapler.
2. Release upper layer tape and carefully glue the bottom of the film to the sheathing.
3. Stepping back 15 cm from the top, stick the next piece of tape without removing the top protective layer yet.
4. Having secured the edges of the membrane with staples, glue the overlap, gradually removing the protective layer from the film. In this case, the film must be straightened.
5. Lay in a similar way required amount rows. Cover the ridge with a solid sheet, making a sufficient overlap, avoiding the joint at the corner. Cover the other side of the roof in the same way.
6. The laid membrane is additionally secured along the edges of the roof using beams with a cross section of 3x5 cm. This is important, because these parameters are necessary to create an optimal ventilation gap. Condensation will escape through it.
7. Mount the sheathing, securing the beams with self-tapping screws.
8. Install roof covering, paying Special attention ventilation in the area of ​​the ridge and cornice.

When laying the membrane, it is necessary to ensure the integrity of its surface. If defects are found in the fixed area, the damaged blade should be replaced or (if the damage is minor) sealed with mounting tape.

Features of installing a vapor barrier for wall insulation

It is necessary to install a vapor barrier on the walls only if it is used mineral insulation and/or their outer surface is located on the street. It is especially important how to properly install the vapor barrier film on the walls. To do this, using the above accessories, do the following:

• position it with the appropriate side and carefully secure it to the sheathing, being careful not to damage the surface;
• carefully glue puncture sites, overlaps and possible cracks;
• install the sheathing using beams with the cross-section indicated above to create ventilation;
• cover the structure wall panels, plasterboard or other finishing material.

When installing insulation from stone wool it is necessary to use vapor barrier and waterproofing (windproof) films to protect the insulation from vapors and moisture. If this is not done, the insulation will quickly pick up moisture, which will lead to significant loss of it. thermal insulation properties and to rapid spoilage.

There are many manufacturers of such films (Nanoizol, Izospan, Rockwool, etc.), but they are all produced according to similar principles. Vapor barrier is marked “B” in the name, wind protection is marked “A”. These films are attached different sides to the insulation. Let's consider them separately.

Which side to attach the vapor barrier

The vapor barrier film has one smooth side and the other has a rough structure. This is done so that water vapor absorbed on the film does not collect in drops and flow down, but is evenly retained on the surface of the film and then evaporates again into the air. Otherwise, water accumulations could form at the bottom of the wall or pitched roof, causing rotting processes in the finishing materials.

This means that the vapor barrier needs to be mounted with the smooth side facing the insulation, and rough side inside the room.

Which side to attach the windproof film

Windproof film, unlike vapor barrier, has two functions: protecting the insulation from atmospheric moisture, and removing water vapor from the insulation to the outside. Waterproofing (also called windproof) film also has smooth and rough sides. The rough side is designed to absorb water vapor from the thermal insulation and remove it outside. The smooth side should collect moisture and, without allowing it to be absorbed, quickly remove it from the insulation.

Thus, the wind protection is attached with the smooth side outward and the rough side to the insulation.

Don't forget to use tape to hold the pieces together protective films between each other during installation so that moisture does not penetrate to the insulation through the joints.

When installing 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, and characteristics. In addition, you should know which type of materials is suitable for a wooden base, and which one is needed for concrete slabs ceilings Let’s look at the questions in more detail, let’s figure out how to install a vapor barrier on the ceiling and whether it’s possible to do the work yourself.

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 sub-zero levels, for example, a room under an unheated attic or roof, then condensation will collect in a certain area of ​​the structure. This area is called the dew point and it is important to move this point beyond the insulation layers. Otherwise, floors, supporting structures and thermal insulation will begin to get wet, rot and become unusable in a short time.

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

Advice! In rooms with variable humidity, laying out a vapor barrier is a necessary condition. The suspended water rises to the top; it is necessary to ensure timely release of steam so that mold does not form in the room.

Types of vapor barrier materials

The product range is large:

1. Reinforced polyethylene films. They have zero moisture absorption and cope well with protective functions. For zones high humidity it is better to use films with perforations, and for rooms with normal level moisture, non-perforated products are suitable. The availability and versatility of the material are advantages, but the ability to collect condensation on the surface is a disadvantage.
2. Polypropylene tapes with viscose coating - an option that is suitable for all types of premises. Viscose absorbs moisture without forming condensation. Increased strength and ease of installation are advantages; the high cost of the material can be a disadvantage.
3. Foil-coated insulation It is made of foamed polyethylene or thick cardboard, covered with foil (on one or both sides). High quality, reliability, durability and ability to display heat are advantages. In addition, the products are small in thickness and are indicated for installation in baths and saunas.
4. Vapor barrier membranes. Modern material, consisting of several layers: perforated fabric, polymer film, polypropylene. The main quality is 100% vapor barrier. The membrane collects all the moisture without giving it back. Particularly effective are 2-sided insulators, which successfully remove all moisture to the outside. For processing concrete surfaces Varnishes and mastics with a membrane effect are offered.
5. Glassine is a durable cardboard impregnated with bitumen. It is distinguished by its 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 the purpose, scope, protective characteristics and base materials for which the product is best suited.

Operating principle 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 the principle of operation of the products differs. For example, the film does not allow moisture into 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 install a vapor barrier on the ceiling - unlike film products, membrane rolls installed incorrectly will release moisture inside without allowing it to pass 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 protect the wood from moisture and to ensure ventilation of the structure and the “insulation pie”.

Suitable:

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

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

For concrete ceilings

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

Features of vapor barrier installation and fastening technology

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

On a note! Wooden ceiling it needs to be treated with an antiseptic, fire-resistant impregnation, and only then primed.

On a wooden ceiling base

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

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

Important! When using a vapor barrier membrane, first consider the material and determine which side to place the vapor barrier on the ceiling. The smooth side is laid out towards the ceiling, and the rough surface is “turned” towards the room.

After installing the insulation, a lathing 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 ceiling vapor barrier, and will serve as the basis for finishing ceiling. Attach the sheathing with self-tapping screws, sewing it to the base base.

On concrete ceiling bases

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

Once the base has dried, vapor barrier materials can be applied. Polymer mastic is considered a good solution - the mixture protects well from moisture vapor, and also does not allow water to pass through from above if there is a gap left somewhere in the ceilings. The mastic is applied according to the manufacturer's instructions; all information is written on the packaging; it should be carefully studied.

When using rolls, sheet materials, on the base a sheathing is formed from wooden beam or metal profile. The size of the cells must correspond to the size of the insulation sheets. Many craftsmen prefer to measure insulation rather than vapor barrier materials - first the insulation elements are laid out in the cells, and then the membrane or film.

How to attach a vapor barrier to the ceiling:

• on wooden sheathing staples (a construction stapler will come in handy);
• on metal structure with tape.

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

After the installation of the ceiling vapor barrier is completed, the sheets are pressed against another sheathing frame so that the necessary ventilation gap remains. If the ceiling then tightens tension fabric, then to form the second frame of the sheathing it is permissible to take thin dies so as not to weigh down the entire structure. And in case of formation suspended ceiling or hemming the surface with plywood, gypsum board, the timber must be strong enough, otherwise false ceiling will collapse.

Why does condensation appear on vapor barriers?

Having figured out how to properly install a vapor barrier on the ceiling, many owners are still faced with the formation of drops on the surface of the materials.

There are several reasons:

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

AND main mistake– the vapor barrier membrane is laid on the wrong side. Let us remind you: to ceiling surface(to the rough ceiling) the smooth side is turned, and the rough side “looks” into the room. If you are afraid of making a mistake, take a 2-sided foil insulator; in addition to protection from moisture, the product has the ability to retain heat, which is an additional advantage of the insulator.

During the construction of residential buildings, a wide range of work has to be performed, among which the installation of vapor barriers plays an important role. Its implementation should be approached with all responsibility, since this determines the stability of the level of air humidity in the room. Properly performed vapor barrier allows, in addition to ensuring optimal thermal regime indoors prevent negative impact from steam and condensate.

Realizing the importance of performing heat and vapor barrier, owners do not always manage to do this work correctly. And among the questions that often arise, the following is particularly relevant: which side should the vapor barrier be placed so that it provides an optimal microclimate in the room.

This issue must be given special attention before work begins. You can figure out which side the vapor barrier film should be placed on the surface only after familiarizing yourself with the process of laying walls, including insulation. Thanks largely to this information, it will be possible to understand which side should be placed on which materials.

General description of the vapor barrier process

First of all, you need to pay attention to the base - it must be clean from dirt and dry thoroughly. Priming is also a mandatory procedure. If you have to deal with a metal surface, it must be degreased. While working on the roof, a vapor barrier can be laid without additional substrates.

As for the floor and walls, in this case the following scheme is followed:

• the first layer is insulation;
• then waterproofing is laid;
• at the very end it is the turn of the waterproofing material.

It is very important that the film is positioned as evenly as possible. It should not be over-tightened or drooping.

In order to carry out the installation of vapor barrier efficiently, during this work it is necessary to adhere to certain rules. The main one is ensure proper protection of the insulation, and for this vapor barrier material must be laid on inside spaces between a layer of thermal insulation and internal lining. The choice of vapor barrier side is largely determined by what material you have to work with.

If we talk in more detail about the vapor barrier installation scheme, its essence will boil down to the following.

• If we consider the structure of Izospan, then we can distinguish two layers in it, which are complemented by a rough coating. Moreover, the latter is necessary so that condensation accumulates on it and evaporates faster. Correct styling involves placing material on the inside. In this case, the smooth side must be pressed as firmly as possible against the sealing surface.
• If you have to work with plastic film, then it can be laid on any side. However gaps must be maintained and do not allow the material to be pulled too tightly or too loosely.
• If membrane materials are used, then such installation is carried out in accordance with the pictogram on the reverse side.
• Penofol should be laid in such a way that its foil side faces inward.
• Polypropylene film with a two-layer structure is placed on the floor so that its smooth side is directed towards the insulation, and the rough part faces the direction of the room.
• Correct installation of metallized film with foil requires its placement in such a way that the foil faces the insulation.
• If polypropylene with a one-sided laminate is used as a vapor barrier material, then it should be placed with the smooth side facing the insulation, and the braided part should face inward.
• To effectively operate a microperforated membrane, it is laid in such a way that the marked side faces the roof. Here it is very important to maintain a gap between the insulation and the film, then the material will remain intact and will be able to successfully perform its function.

Necessary materials

Regardless of the material used to perform the vapor barrier, the technology for its creation requires the use of the following materials:

Classification of vapor barrier materials

When choosing a material for vapor barrier, it is necessary to take into account that it must have certain characteristics:

• high strength;
• low thermal conductivity coefficient;
• fire resistance.

Unfortunately, the industry cannot yet offer universal material to carry out such work. However, there are many products worthy of attention, among which are the following:

Vapor barrier technology

The process of laying a vapor barrier involves the following steps.

How to properly install a vapor barrier on a ceiling?

An operation such as vapor barrier must be performed on all surfaces without exception, including the ceiling, roof, floor and walls. And, first of all, let’s take a closer look at the features of installing vapor barrier on the ceiling.

Protection from moisture is necessary for the ceiling due to the fact that it is constantly exposed to the negative effects of water vapor arising from high humidity in the room. Such conditions arise indoors due to the fact that we regularly have to perform such household operations as washing, bathing, cleaning, cooking, etc.

All these processes are accompanied by the release warm air who strives upward and looks for ways to get out. However, the ceiling does not allow this. Using a vapor barrier allows you to extend the service life of these materials and at the same time prevent the formation of fungus and mold in the attic. A positive aspect of using a vapor barrier is that it gives the ceiling increased fire resistance.

In accordance with the technology of laying vapor barrier on the ceiling, prepared the material is fixed to the rough ceiling surface, clamping it with a metal profile or lathing. While rolling out the rolls, the owner will have to deal with streaks. They must be overlapped with each other by 10-15 cm. To connect the joints to each other, it is recommended to use special self-adhesive tapes.

How to perform a vapor barrier on the floor, roof and walls?

Steam can also negatively affect the condition of the floor. First of all, this applies to the first floors, which serve as the ceiling for basements, and, in addition, for the surfaces of baths and saunas.

Installation rules

The technology for laying the material involves carrying out work in the following sequence:

When laying the film, you must ensure that it is not stretched too tightly. It is also not recommended to allow it to sag. Pieces of vapor barrier must be overlapped, using as fasteners Double-sided tape or special staples.

An important point is that the coatings must be laid out in two layers: the insulator should lie below the insulation, outside and on top.

If you have to solve this problem in large rooms, then the material should be used liquid rubber from bitumen. The application technology is reduced to manual installation or you can use the compressor method. By waiting for it to dry, you can subsequently see the appearance of an elastic film of rubber that will reliably retain moisture.

Realizing the importance of vapor barrier, the owner must ensure that it is carried out on all surfaces of the house that may be exposed to moisture. Besides that you need to choose the right material To perform this work, you also need to figure out which side to lay it correctly. Only in this case can its effective functioning be ensured, which, in turn, will extend the service life of the coatings on which it is created.