Installation of a vapor barrier is mandatory during the construction of residential buildings: the membrane protects the insulation from vapors emanating from the premises 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 the 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 steam insulating materials in the construction market, it is difficult to create a comprehensive guide to their installation. Detailed information is 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, the lightest 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 top 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 one yet protective layer.
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. Likewise lay down required quantity 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. Install the sheathing, securing the beams with self-tapping screws.
8. Install the roof covering, paying attention 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 outdoors. It is especially important how to install correctly 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.

During construction country house or private bath important stage is thermal insulation of various surfaces. In addition, the insulation itself needs high-quality and reliable vapor barrier protection.

To prevent negative impact external factors and the formation of condensation on the heat insulator, any homeowner must have general idea about how to properly install a vapor barrier to ensure a long service life of the entire structure.

Membrane structure and operating principle

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

They consist of three layers, each of which performs an important function. The first layer prevents the penetration of steam into the insulation, the second provides the necessary strength of the base, and 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, allowing dried air to penetrate. The reinforcing layer retains warm air masses inside thanks to a special weaving of threads. The third layer provides a sufficient level of traction inside the structure.

Some types of membranes have an additional anti-condensation layer based on viscose or cellulose. She holds excess moisture, deposited on paper fibers. To naturally remove moisture from the membrane, a technological gap of 2.5 cm is provided between the vapor barrier and the finishing surfaces.

Features of vapor barrier installation

An important stage in protecting insulating materials is laying a reliable vapor barrier layer. All work is carried out during the repair or reconstruction of a finished building or during the construction of a new building. To correctly install a vapor barrier, you need to understand how to connect membrane sheets and which side to fix them to the insulating base.

Preparatory work

At this stage, work is carried out to select the appropriate type of vapor barrier, taking into account the features of the installation process, performance characteristics and material requirements.

Before laying a vapor barrier, you will need careful preparation surfaces. Here it is important to consider the type of material used in the construction of floors, walls, ceilings and roofing structure.

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

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

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

Technology for laying vapor barrier on the ceiling

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

Roll or block insulation is installed in the space between the rafters and joists, best option– mineral or basalt wool. Next, you can lay vapor barrier protection on the ceiling surface.

When the thickness of the insulation is equal to the height of the logs, an additional slatted counter-lattice is installed to maintain natural ventilation.

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

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

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

The height of the sheathing is determined based on the thickness thermal insulation material and minimum technological clearance for ventilation. The installation step is 3 cm narrower than the width of the heat insulator, which allows for high-quality installation of the insulator into the prepared sheathing cells.

Technology for laying vapor barrier on the floor

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

The wooden floor is insulated using joists, on which a waterproofing layer is laid. Next, insulation is placed in the space between them - wool on a mineral or basalt basis. After this, vapor barrier material is laid.

The rolled material must be laid with an overlap of 12 cm, with the joints carefully sealed with metallized tape on both sides. A properly laid vapor barrier should completely cover the floor surface with an overlap of up to 10 cm on the walls.

To install vapor barrier protection on concrete base, you will need to install a sheathing in the cells of which the waterproofing layer and a heat insulator.

Choosing a side for installing a vapor barrier

Once the material for the vapor barrier has been selected, you should consider important question– which side to attach the vapor barrier to the insulation. Such materials can be fixed as follows:

• Polyethylene films (reinforced and plain) are laid on any side, which does not impair the protective properties of the material.
• Foil films are installed with the reflective side facing the inside of 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 with a rough surface - inside the room.
• Foam-based insulators are laid similarly to membrane materials.

Important! Before laying the vapor barrier to the insulation, it is recommended to spread the prepared material on flat surface to correctly determine the internal and outside.

The face or the back of a vapor barrier?

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

The vapor barrier cake must be placed so that the protection is directed towards the heat insulator on both sides with the smooth back side, and with the rough front side facing the inside of the room.

The rough surface provides protection from moisture penetration into the insulation, and the smooth surface promotes maximum heat accumulation.

Determining the width of the overlap when installing the membrane

There are special markings along the edge of the insulating membrane 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. At the ridge the overlap is 18 cm, at the valley - 25 cm.

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

Is a layer required for ventilation?

At the bottom of the membrane vapor barrier there is a 5-centimeter ventilation gap, which helps prevent the formation of condensation on surfaces and the heat insulator.

Diffusion membranes can be attached to insulation, plywood sheets 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 roof structure, a counter-lattice is used. In the process of fastening a ventilated facade, a technological gap is created when installing racks located perpendicular to the vapor barrier.

Elements for fastening vapor barrier

To reliably fasten a membrane or film vapor barrier, nails with wide heads or metal are used construction staples. Most practical option fasteners - counter rails.

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

To ensure long service life modern insulation materials, 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 one suitable material and know how and which side to lay to the heat insulator.

First of all, you must follow the manufacturer's instructions, which clearly describe which side to lay the windbreak on. If there is no such instruction, there are a number of general recommendations, applicable for windproof films:

• the wind protection spreads towards the insulation with the “fleecy” side, unless otherwise specified in the instructions;
• if both sides are the same, the film is attached with the manufacturer’s logo on the outside;
• wind protection without markings and distinctive qualities of one of the sides can be installed in any convenient way.

Manufacturers often roll rolls in such a way that the wind protection can be laid as simply as possible - as the roll unwinds.

Windproof films of different types are laid in different ways:

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

Laying windbreaks on the floor

On internal floors, the film is spread over the insulation with the markings facing outward and the plain side inward.

And to protect the wooden floor from cold wind blowing from an uncovered base columnar foundation, the film is laid on the subfloor without gaps close to the insulation. In this case, it is laid with the inscriptions down.

How to lay a windbreak on a roof

Single layer windproof films are laid under the roof on either side. But two-layer ones - only with the smooth side up.

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

How to install windbreaks on walls

On the walls, wind protection is placed on the outside directly on the insulation (with the markings or the colored side facing out). It is necessary to provide a ventilation gap between the film and external finishing. In order for the wind barrier to provide a sufficient level of protection from moisture, it must be mounted horizontally from bottom to top with an overlap of at least 10 cm. Inside, a vapor barrier is laid on the walls - this is very important

Any homeowner spends a lot of effort to create comfortable living conditions for his family.

This is maintaining a constant temperature in the home, ensuring an influx fresh air, humidity is within normal limits. All life activity of any living creature is accompanied by the release of heat and steam.

Wet cleaning and washing, showering and cooking, boiling water, and even breathing - all this is a source of accumulation in the room. Increased humidity leads to the formation of condensation on various surfaces indoors.

Moisture penetrating deep into the structure in wooden house, has a negative impact on them, and contributes to their deterioration and even destruction. The materials used for construction are covered, and pockets of rotting form on them. Besides, high humidity does not have the best effect on the well-being and health of people living in the premises.

To avoid damage and deterioration individual elements floor, use a special one. His functional purpose– prevent the harmful effects of moisture. At the same time, it does not interfere with air circulation; it calmly goes outside. This technique allows the floor ones not to lose their working qualities and ensures their long service life.

Almost until the end of the second millennium, the role of vapor barrier material was usually played by roofing material, glassine and roofing felt.

Today we can observe the widest range of insulating materials different types and parties, some of which can also protect from water.

For wooden buildings Various breathable films and membranes are most often used as a vapor barrier layer.

In addition to them, there is another type of insulation - bitumen-polymer mastic, liquid rubber, etc. But these materials are more suitable for protecting and not the foundation of the building.

Polyethylene film

Perhaps the most affordable and common type of vapor barrier material for installation. Trade presents two types of synthetic films - perforated and non-perforated.

It is believed that the first is more suitable for, and the second for insulating from steam. Their difference lies in the presence or absence of microscopic holes in the material, and, accordingly, in the level of permeability.

Thanks to innovative technologies Improved versions of familiar materials are appearing on the market. These are, for example, films with a layer of aluminum applied to them. They have much better performance characteristics and high vapor barrier properties.

They are preferably used where extremely high levels of humidity and temperature are possible. These are kitchen facilities, saunas, and so on.

Like any material, film is not without its drawbacks. The main and most significant thing is that it is very easy to tear, which should be taken into account when using and installing. Even if you use a reinforced type of material (reinforced with a special mesh), its strength and durability will not be particularly high.

Polypropylene film

A material such as polypropylene, compared to polyethylene, has better resistance to atmospheric precipitation and has higher strength. At first this type The vapor barrier material was made strictly from polypropylene. Later it was discovered that condensation accumulated on the film on the insulation side. It has a negative impact on the quality of the insulation and provokes its premature failure.

This drawback was eliminated as follows. A special viscose-cellulose layer is applied to the reinforced polypropylene film. It prevents the formation of drops, perfectly absorbing and retaining moisture. During installation, such material is placed with the anti-condensation layer down. Ventilation gap usually done between a layer of this film and.

Diffuse membrane

Breathable diffuse membranes can easily be considered the most expensive and high-quality vapor barrier materials. This material is extremely high rate vapor permeability, which is ensured by the special microstructure of the material. It is a non-woven fabric made from synthetic fibers.

They are used not only to protect against excess moisture, but also to control its required level. This ability is provided to them by a special quality - the ability to pass air on one side or both. According to this quality, membranes are divided into double- and single-sided. The specific installation method used for each type depends on this. When using single-sided film, you need to make sure which side is facing the layer.

Breathable membranes are also divided according to the number of layers that make them up: there may be one, two or three.

In the manufacture of membranes, a special anti-condensation layer is used, which has the ability to absorb excess moisture and then gradually evaporate it.

A unique representative of diffuse multilayer membranes is a special intelligent membrane. It successfully combines steam, hydro and heat insulating properties. This material is able to independently regulate the microclimate in the room (by changing the vapor exchange), based on the level of moisture and temperature present there.

Another invaluable quality of a diffuse membrane is the absence of the need for arrangement between it and. Well, and of course, there are shortcomings, where would we be without them. There is only one, but it is quite sensitive - the high price of such a vapor barrier for the floor covering. But the positive properties and advantages of the material more than compensate for it.

Liquid rubber

Liquid rubber today is a fairly actively used material for arranging vapor barriers. What does this name even hide?

This is a bitumen-polymer cold emulsion prepared at water based. It is convenient to spray it on the working surface. This simple application makes it easy to apply even on surfaces with complex terrain. After final hardening, the mass forms a monolithic rubber carpet that has no seams.

It poses an insurmountable threat to liquids and gases, and is also characterized by sound, hydro and heat insulating qualities.

Today's liquid rubber There are different types:

• A special emulsion applied to the surface manually. Working area for application it should be no more than a few tens of meters.
• An emulsion for which special coatings are used. automated systems. Used in cases where we're talking about about vapor barrier of large floor surfaces: hundreds and thousands of squares in size.

Floor: proper vapor barrier

If it is necessary to arrange quality system vapor barrier in a house under construction, then there will not be so much hassle with it. All floorboards must be treated with specialized products that protect the wood from pests and insects.

This especially applies to lags and subfloor, which are closest to, in close proximity to it. It is this that will become the basis on which the vapor barrier layer will lie.

If you need to equip an already erected structure with a vapor barrier, then the hassle will increase, and the technology will be different. If you need to carry out major renovation, or replace the vapor barrier layer, you will have to lift and remove the floor covering, remove and remove the heat and vapor barrier.

The screed is thoroughly cleaned with a broom or even a vacuum cleaner. A careful inspection is carried out to check for possible defects. They can be unevenness, chips, small and large cracks.

Dampness without vapor barrier

If there are a lot of them, then repairs should be carried out. If necessary, the screed must be leveled to prevent possible moisture from entering through the cracks from the outside. You can install an additional one to protect against water penetration from the ground.

If a roll is used for this waterproofing material, then it must be overlapped. All resulting joints are sealed with simple adhesive tape or tape.

The level of each of them must be strictly adjusted so that the surface is perfectly horizontal. All elements and parts made of wood are impregnated with protective. The surface is cleaned of debris and dust, and only then you can begin laying the vapor barrier layer.

Laying vapor barrier

For proper styling some kind of vapor barrier layer special knowledge not required. Usually, widely used film materials are used to create a vapor barrier with your own hands. Their worthy representatives are the Izospan B floor vapor barrier and the Izospan membrane. The vapor barrier layer is carefully laid on the supporting frame, making sure that the material sheets overlap strictly. Its width must be at least 20 centimeters.

Secure the laid layer with construction stapler or special galvanized nails. Often, the material manufacturers themselves recommend using a special adhesive tape, which provides a virtually monolithic coating, without holes or cracks.

So that during work there are no questions regarding possible ways fastenings, it is better to clarify this issue in advance when purchasing the material.

It is convenient to protect all kinds of junctions, parapets, relief areas and other hard-to-reach places using bitumen-based coating materials. Laying film vapor barriers in them can be very difficult.

After placing the vapor barrier layer, insulation is mounted on top of it. It could be , or . The insulation is laid in such a way that it fits snugly, without cracks or gaps, against the joists.

Another vapor barrier layer should be placed on top of it, which will become an obstacle to moisture escaping from the room. You should carefully monitor the location of the membrane - strictly overlapping.

Then the joints are glued, and you can begin laying the main floor. When laying boards, keep in mind that there should be a gap of one to two centimeters between the floor and the vapor barrier.

How to install vapor barrier correctly

How to determine which way to lay vapor barrier membrane: which side?

Tape the seams with foil tape

If a film of two layers is used in the process, then, according to the instructions, it should be laid with the rough side, which can retain moisture, towards the room, and the smooth surface, which prevents moisture from entering, towards the layer