Vapor barrier: which side to lay, how to lay waterproofing. Correct installation of vapor barrier on the roof - stages and technology of work Which side to lay the waterproofing on the roof

Moisture does not penetrate into the room thanks to reliable roofing material. But don’t forget about the steam that rises from the living quarters. It penetrates into the under-roof space, precipitates and can adversely affect thermal insulation material, wood and metal.

Therefore, it is necessary to ensure high-quality insulation of the roofing pie. To prevent the development of such events, you need to know how to lay waterproofing on the roof. Otherwise, this may negatively affect the condition of the insulation. It loses its properties when exposed to moisture or wind. Moisture can come from cracks in the roof surface or condensation precipitated by steam.

In this article

Why is moisture dangerous for the roof?

Why is this happening? Everyone knows that warm air rises to the ceiling. Through miniature cracks it enters the under-roof space. In winter it is often cold here. Warm steam, penetrating into the insulation, precipitates and condensation forms. These droplets subsequently turn into ice. As a result, the thermal insulation material is destroyed.

As soon as the frost subsides, the ice begins to melt, which, flowing down, can penetrate into the layers of the interior decoration of the room. As a result, the finishing structure is destroyed, which means that repair work to restore the building and roof is not far off.

As for the thermal insulation material. Mineral wool will collapse after the first winter. Foamed polystyrene will last a little longer, but it will still become unusable in the near future.

Waterproofing

In order not to think about repairs again in the near future after installing the roof, you need to worry about high-quality waterproofing in advance, using vapor-proof material. It will not penetrate the layers of insulation wet air, preventing the occurrence of condensation and mold development in the future.

Vapor barrier will also protect the wood from the negative effects of moisture. Let's consider the installation features of modern materials that are used most often today.

Features of installation of membranes and films

You need to start laying the film from below, heading towards the ridge. The next strip of material should overlap the previous one. The overlap width should be from 10 to 15 cm.

The first row should be laid so that the waterproofing between the rafters sag slightly. You should also leave 4 cm for an air gap. The film is laid in the same way, from bottom to top. The overlap in this case is no more than 15 cm, while between the rafters there can be a sag of up to 2 cm. The edges of the film are connected with a special adhesive tape. Fastening to the rafters is done using a stapler or nails with a wide head.

Then the film is laid with an overlap of up to 20 cm. Counter battens measuring 4 x 5 cm are stuffed on top of the laid film in increments of 15 cm. Then the lathing is installed. When laying waterproofing, you should remember that between the ridge axis and the edge of the film you need to leave a gap of about 5 cm.

In the places where the bars are located, the film is cut. The film is glued to them with double-sided adhesive tape or tape. In buildings with roof windows, the film must be laid taking into account the recommendations of the window manufacturers.
Perforated film should be laid with the perforation facing up. This eliminates the possibility of possible leaks.

Installation of anti-condensation film

After the rafter system and the thermal insulation layer have been installed, you can begin installing the waterproofing film. The pitch between the rafters should not exceed 1.2 m. The anti-condensation film must be laid so that its absorbent surface does not touch the insulation.

The film is overlapped using mounting adhesive tape. In this case, the joints must be located on the rafters. It is necessary to ensure that the film is evenly stretched. Under no circumstances should there be folds. Between the rafters you need to leave 2 cm of sagging to protect the wood from moisture. Fastening is done with a stapler and nails.

A gap of about 5 cm should be left between the thermal insulation and waterproofing layers. Excess moisture should flow along the lower edge into the drainage gutter. After this, you can secure it with 3 x 5 cm slats using nails and insulation.

During installation, it is necessary to exclude the possibility of moisture dripping onto the surface of the insulation. In addition, intersections with additional structures (chimney, antenna, ventilation) must be additionally insulated. To do this, make a trapezoidal incision.

The lower and upper valves must be secured using a special sealing tape. This is done on the horizontal surface of the sheathing. The side flaps are secured in the same way, only they are pulled up.
On roof slopes, horizontal strips of film should be laid overlapping on top. Diffusion and superdiffusion films – perfect option to protect your home from moisture. This material is able to “breathe”. In this case, only the upper gap is left between the membrane and the sheathing for ventilation.

The membranes are laid from bottom to top in strips with an overlap of 20 cm. They are secured with nails.

Before you begin any steps to install waterproofing, you should make sure that the antiseptic impregnation that was used to cover the wood has dried. Only after this can counter battens be placed on the sheathing to ensure the removal of water vapor. Further installation occurs in the same way as for waterproofing films. For fastening use galvanized nails or a stapler.

The membrane joints are connected to each other with double-sided tape. The joints with structural elements also need to be insulated using sealing tape.

Installation of volumetric diffusion membranes

Volumetric membranes must be laid on the flooring parallel to the cornice. Along the top edge you need to secure this material with nails. The next roll is placed in such a way that the fastening area is covered by approximately 8 cm. Using special glue, the intersection is glued together.

In the places where the counter-lattice is attached, a sealing tape is laid on top of the film. The membranes are laid around the chimney in the same way.

So we found out how to properly install waterproofing on the roof using modern materials.

Watch the video and find out which waterproofing is better for the roof and which has proven itself over time.

When insulating a roof or room with a heat insulator (mineral wool, glass wool, loose polystyrene) capable of transmitting and accumulating moisture, it is necessary to install a vapor barrier layer. Moisture that gets into the thermal insulation significantly worsens its performance properties, increasing thermal conductivity. In addition, due to the humid environment, wooden structures with which the insulation comes into contact quickly begin to rot and collapse. At the stage of preparation for insulating a roof or house, it is important to figure out which side to lay the vapor barrier against the insulation - a violation of the technology will lead to steam from the room penetrating into the thermal insulation layer.

What kind of vapor protection is needed?

Types of vapor barrier materials

The primary issue is the choice of material that will protect the insulation from moisture. Classic roofing felt and glassine, which were used for water vapor barrier, have given way to modern polymer films with various operational parameters. Membranes used in construction are divided according to vapor permeability into completely impermeable films and partially permeable (diffusion) films.

Manufacturers offer the following types of vapor barrier membranes: :

• polyethylene film (can be used to insulate a roof or floor, the barrier is vapor and waterproof);
• reinforced polyethylene film (higher strength);
• aluminum foil film (used for internal insulation, mounted with the reflective side facing the room - additionally helps to retain heat, primarily designed for use in saunas and baths);
• film with anti-condensation coating (prevents moisture condensation, intended for installation in structures with metal elements prone to corrosion - corrugated sheets, metal tiles, etc. the film is mounted with the treated side facing the heat insulator).

Reinforced polyethylene film If, when insulating rooms in a house, a completely impermeable film is used to create a vapor barrier, it is necessary to provide effective ventilation premises, capable of removing excess moisture outside.

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

1. Pseudo-diffusion. During the day, up to 300 g/m2 of vapor is passed through.
2. Diffusion. The amount of evaporation passed per day ranges from 300 to 1000 g/m2.
3. Superdiffusive. The evaporation rate exceeds 1000 g/m2.

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

Principles for installing a vapor barrier

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

Preparatory stage

To insulate a block or wooden house or arrange a bathhouse, thermal insulation materials are used, which must be protected from moisture accumulation. For this purpose, a material that does not allow evaporation is installed on the walls inside the house, on the ceiling or floor, on the inside of the roofing pie. Or a diffusion membrane for facade insulation.

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

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

Correctly attaching reflective vapor barrier

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

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

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

How to install a vapor barrier on a ceiling

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

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

Fastening the vapor barrier membrane The foil film sheets are laid without overlap - end-to-end, and the seam is taped with aluminum tape.

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

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

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

Ceiling installation

We will also consider how to lay a vapor barrier on concrete floor. To insulate a ceiling from the inside or flat roof, made of a concrete slab, you need to attach a waterproofing coating (vapor barrier film) to it using self-adhesive tape, and then install a sheathing made of bars or a metal profile.

The correct height of the sheathing should be selected taking into account the thickness of the insulation and the ventilation gap, the installation step should be 1-2 cm less than the width of the insulation, so that mats made of insulating materials fit into the cells at odds. How to attach a vapor barrier to the sheathing will be described in detail below.

How to lay a vapor barrier on the floor

Installation of a vapor barrier membrane on the floor is similar in technology to how vapor barriers are installed for walls and ceilings. After preparing the base of a wooden floor when insulating along the joists, before laying the vapor barrier on the floor, a waterproofing carpet is installed, which should go around the joists. Then a thermal insulator made of mineral wool is inserted between the joists. After which the vapor barrier is laid, it is important to know how to lay the film correctly.

The overlap of the sheets of rolled material should be at least 10 cm, with the joint taped on each side. The resulting canvas is secured in such a way that the overlaps lie on the floor joists, and along the entire perimeter the evenly stretched canvas extends 5-10 cm onto the walls.

Insulated floor with air gap

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

Fastening principles

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

Overlap when installing vapor barrier

In order to properly fasten the vapor barrier, the canvas should be carefully pulled, and the fasteners should be placed in small increments - no more than 30 cm. Installation rules require careful attention to the fastening of the canvas around the perimeter - it is spread and fixed so as to exclude the possibility of moisture penetrating into the insulation.

Before attaching the vapor barrier, make sure that the sheet is positioned right side to thermal insulation.

Which side to install the vapor barrier material

Let's consider which side of the film or membrane is laid to the insulation :

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

Rule for laying vapor barrier to insulation If the front side of the membrane looks similar to the back side, and it is difficult to determine how to properly lay the material, you can conduct an experiment. Cover the bowl of boiling water with a small piece of membrane - whichever side the condensation appears on is the side that is waterproof; it should be facing the insulation.

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

Installation features

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

Diagram of an insulated roof with a ventilation gap

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

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

Preface. When building a private house Special attention attention should be paid to vapor barrier of the ceiling, floor, walls and roof. If this important step is skipped, the building's structural elements will not last long. We’ll talk further about why it is important to install a vapor barrier in a private home and how to do it correctly.

Review of insulation materials

Properties of Rockwool Light Butts

Minvata Izover: characteristics

Knauf insulation: characteristics

Properties of Ursa PureOne mineral wool

Why do you need a vapor barrier for insulation?

A special film that protects the heat-insulating material from moisture is necessarily included in the “pie” of the walls or roof. The fact is that due to the difference in temperature, especially in winter, condensation settles on the walls and ceiling indoors and outdoors. As a result, the heat insulator gets wet and stops performing its functions. The house is getting cold. In addition, moisture leads to damage to the structural elements of the building.

Depending on the variety, the cost of the material may vary. For example, a regular vapor barrier polyethylene film costs about 500 rubles per roll. The foil version will cost about 1400-1800 rubles. A three-layer diffusion membrane will cost about 4000-5000 rubles. The popular vapor barrier “Izospan” will cost about 800-1000 rubles. per roll.

Types of vapor barrier materials

Vapor barrier in a frame wall. Photo

There are only three main types of films designed to protect mineral wool or expanded polystyrene from moisture:

Standard. The cheapest and not particularly durable type of vapor barrier. In most cases, this is ordinary thick polyethylene film.

Foil. It is more expensive than polyethylene, but at the same time, in addition to the vapor barrier itself, it performs another function - it reflects heat back into the room. Owners of country houses are often interested in which side to lay the vapor barrier on the walls and ceiling. This question usually arises in relation to this variety. Let's look at how such a film is actually mounted below.

Membrane. Features limited vapor barrier. This allows you to control the removal of moisture from the room.

Basic rules for laying vapor barrier

Of course, before you go to the store to buy film, you need to do everything necessary calculations. This procedure is completely easy to perform. All you need to do is calculate the area of ​​all structural elements of the house that require protection. The calculation is made taking into account the width of the vapor barrier film and the required overlaps.

How to distinguish the inside from the outside

Photo of vapor barrier under magnification

If the manufacturer’s instructions are missing or do not contain the necessary information about which side of the film is considered internal, then you should independently determine this based on external factors. Please note the following:

If the waterproofing film has a different color on both sides, then the light side of the isospan is laid against the insulation;
. The side of the waterproofing that faces the floor when rolled out is considered internal and should face the insulation;
. External side it is made fleecy so as not to allow moisture to pass through, and the inner side is smooth and is laid towards the insulation.

Which side should the vapor barrier be placed on the insulation?

Of course, it’s also worth knowing how to install this type of vapor barrier. In this case, as in all others, the sheathing is initially installed. The sheets are mounted on it and secured with self-tapping screws. The joints are taped with tape.

Which side to lay the vapor barrier on the floor

Video. Which side to lay Izospan on the insulation

(votes, average: out of 5)

Vapor barrier: everything you need to know about protecting insulation from moisture

What is vapor barrier, why is it needed, and how is it performed? I've thought about this before. Now, having gained experience in this matter, I will accurately convey the technical aspects and describe step by step the technology for installing vapor barriers.

The vapor barrier affects not only the effectiveness of the insulation, but also the durability of the structure

Why do you need moisture protection?

Why do you need a vapor barrier at all? As you might guess, its purpose is to protect surfaces from steam. Moreover, we are talking not only about visible steam, but also moisture, which is always present in the air.

Inside the home, the humidity level is almost always higher than outside, which is explained by cooking, washing and taking water procedures. Since steam moves towards the cold - outwards, excess moisture can significantly reduce the life of building structures and the effectiveness of insulation.

Insulation of walls from the inside with mineral wool must be done using a vapor barrier film

Protection is necessary in the following cases:

• When insulating walls from the inside with mineral wool. As is known, the level of vapor permeability and moisture absorption of mineral wool is quite high.
  Therefore, the absence of a vapor barrier can lead to the accumulation of moisture inside the insulation. This in turn will lead to a decrease in the efficiency of the insulation, dampness of the walls, the formation of fungus, etc.;

Frame walls insulated with foam plastic from the inside must be protected from moisture with a vapor barrier

• When insulating frame structures. Vapor barrier is necessary for frame walls, wooden floors and pitched roofs, not only when using mineral wool insulation, but also polymer insulation, which has zero vapor permeability.
  The fact is that zero vapor permeability of thermal insulation leads to the fact that all moisture rushes into the elements of the wooden frame. As a result, the tree quickly becomes unusable;

Vapor barrier film must be used when insulating floors

• When insulating floors. In this case, vapor barrier allows you to protect the insulation from rising steam.

If mineral wool is used inside partitions, vapor barrier need not be used, since there are no temperature differences in the partitions that could lead to the formation of condensation.

As we found out, the vapor barrier should not allow air to pass through, which carries moisture. Therefore, the vapor barrier film should not be confused with waterproofing, which often has the ability to allow air to pass through.

The following materials are currently used for vapor barrier:

Polyethylene

Polyethylene films are the cheapest vapor barrier option. As a rule, polyethylene film is used for waterproofing interfloor ceilings and walls.

Single-layer polyethylene film is cheap, but not durable

Kinds. There are several types of polyethylene films:

• Single layer. The cheapest, but not durable, and also unstable to mechanical loads;
• Reinforced. They are a three-layer material. The middle layer is made of fiberglass mesh.

Reinforced film has tensile strength

Thanks to the reinforcing layer, the film has higher strength and durability;

• Foil. main feature The advantage of these films is their ability to reflect heat.

Pictured is polypropylene vapor barrier film– it has high strength and long service life

Polypropylene

Polypropylene vapor barrier films are the most popular, as they are superior to polyethylene films in all respects. In particular, they are stronger, more durable, and resistant to UV radiation and temperature changes.

Another feature is that these films usually have a two-layer structure. As a result, one side has a rough surface.

One side of the polypropylene vapor barrier has a rough surface that retains moisture

This is done so that the villi retain moisture on the surface of the coating and thereby allow it to evaporate. Beginners often ask which side to put the vapor barrier on?

The material is laid with the smooth side against the insulation, and the rough side against the cladding. True, if you mistakenly attached the canvas with the rough side to the insulation, this is not a critical mistake, since in any case the material does not allow moisture to pass through.

Therefore, between the film and finishing material a ventilation gap is required.

Vapor barrier axton from the French manufacturer Leroy Merlin has proven itself as a reliable and durable material

Price. Below are the prices for popular vapor barrier materials that have proven themselves well:

Nuances of installing vapor barrier films

Basic Rules

So, we have figured out the types of vapor barrier materials. However, the quality and effectiveness of steam protection depends not only on the type of material, but also on the quality of its installation.

Therefore, finally, we will consider the technology of laying vapor barriers. But first I will give some important rules installation:

• The vapor barrier is attached to the housing side. Since steam flows move from inside the room to the outside, the vapor barrier is always installed from the inside, which allows for a sealed circuit;

The vapor barrier is always mounted on the inside of the insulation

• The film must be positioned correctly relative to the insulation. I have already said above which side to lay the vapor barrier against the insulation - smooth towards the thermal insulation, rough towards the finishing;

Diffuse membrane allows moisture to pass in one direction

• On the outside, the insulation is protected by waterproofing. It is almost impossible to provide complete protection of thermal insulation from steam. To allow penetrating moisture to leave the insulation, it is covered on the back side with a waterproofing diffusion membrane.
  This material is capable of transmitting moisture only in one direction;
• The vapor barrier coating must be airtight. To ensure that the film does not allow steam to pass through, it is necessary to seal the places where it is adjacent to the frame, and also to glue the joints of the films with double-sided adhesive tape.

Installation technology

Let's look at the film installation technology using the example of vapor barrier for frame-type walls. This procedure can be divided into several stages:

Instructions for using vapor barrier are as follows:

Sources:

Often waterproofing is installed water-repellent side in the direction from which moisture can penetrate. For example, roof waterproofing is laid on top of the insulation with a water-repellent layer facing up. And on the floor and walls, the water-repellent layer is directed away from the insulation, while waterproofing can be used both inside and outside the building.

How to determine the water repellent side for different types waterproofing:

Read also: Which side to lay Ondutis films

Which side is the waterproofing placed on the floor?

Depending on which side protection from moisture is needed, the waterproofing spreads:

• water-repellent side down - when laying under moisture-absorbing insulation on concrete or earthen floors;
• water-repellent side up - directly under the screed to protect floors in very wet areas.

Read also: Installation of waterproofing for the floor

Which side to lay waterproofing on walls

The principle of waterproofing walls is the same as that of floors. If you need to protect the insulation or walls from an internal source of moisture, the waterproofing is attached inside with the water-repellent side facing the room. And to protect the walls from the outside, the moisture-repellent layer should be directed towards the street.

See also: Video of wall waterproofing

Which side is the waterproofing placed on the roof?

The water-repellent side of the roof waterproofing should be directed outward from the insulation. After all, with its help, the insulation is protected from moisture penetrating from the outside - when precipitation or condensation forms under the roofing. The rough side should absorb moisture from the insulation and evaporate it.

See also: Roof waterproofing video

Which side to lay waterproofing under metal tiles

Due to its characteristics, metal roofing (made of corrugated sheets, metal tiles) requires special waterproofing - special anti-condensation films. This is the only type of waterproofing that is attached with the fleecy side facing out. It is thanks to the moisture-absorbing outer layer that protection is achieved metal roofing from corrosion - all absorbed moisture quickly drains away without lingering.

See also: Video of waterproofing under metal tiles

Do you need waterproofing on the ceiling?

The ceilings in the rooms are covered only with vapor barrier; waterproofing on the inside of the rooms is not used even in the bathroom or sauna. Otherwise, the interior decoration will regularly get wet - after all, the waterproofing will remove condensation from the insulation into the room.

January 12, 2017

The introduction of each new technology in the field of construction provides an opportunity for a person to improve their own housing, which as a result becomes even more reliable, safe and comfortable. But for this it is also necessary to strictly adhere to established standards and construction norms during the construction of a house.
One of the main structural elements of a house that ensures comfortable living in it is the roof. Therefore, it is imperative to know the technology of laying a vapor barrier layer on the roof.

The need to install a vapor barrier

The steam generated inside the room mixes with warm air and, according to the laws of physics, rises. But, since its further advancement is impeded by the roof of the house, it penetrates the thermal insulation layer, beginning its destructive effect.

In winter, due to the sharp difference in internal and external temperatures, steam will be contained in the insulating material. As a result subzero temperatures the steam will first turn into frost, then into ice, respectively, the thermal insulation layer will freeze and remain in this state until the onset of heat, then thaw. As a rule, the consequences of such a process are the complete loss of the protective properties of the insulating material, that is, its unsuitability for further use.

In order to prevent failure of the insulation after just a year of operation, it is necessary to install a vapor barrier on the roof. The vapor barrier material will prevent moisture from entering the insulation and, accordingly, will significantly extend its service life.

Materials used to construct a vapor barrier layer

Previously, the only material installed to protect the roof from moisture was glassine. Today, a wide variety of building materials are used to construct a vapor barrier layer on the roof.

• Regular low density polyethylene film. Due to its low density, experienced roofers do not recommend using it in private housing construction, as there is a high risk of damage during installation and operation.
• Polyethylene film reinforced with a polymer mesh. This is a denser, stronger insulating material, which is most often used for arranging the roofs of agricultural enterprises. It is also not recommended as a vapor barrier for roofing in multi-apartment and private housing construction, since microscopic cracks form at the junction of polyethylene with reinforcing elements, through which steam can penetrate.
• Bag fabrics made from polypropylene threads, which are subsequently laminated using molten low-density polyethylene. Thickness vapor barrier material less than half that of reinforced polyethylene film. This vapor barrier material is used for arranging cold roofs.
• Aluminum foil, which has zero vapor permeability.
• Cardboard laminated on one side with polyethylene film.

A vapor barrier fabric made of several protective layers is used for roofs over rooms in which swimming pools, showers, laundries, etc. are installed.

Which side is the vapor barrier installed on?

• A standard vapor barrier film consists of two layers. At the same time, on the one hand, it has a rough surface that holds back drops of condensation, on the other, it has an absolutely smooth surface. It is the smooth side of the vapor barrier film that is adjacent to the insulating material, and the rough side is directed into the room.
• When using foil film for vapor barrier, which is intended not only to protect insulation, roofing, and foundations, but also to return thermal energy back into the room, it is laid with a reflective surface in the room.
• A vapor barrier membrane that can allow air to pass through, protecting the foundations and roofing from moisture penetration, provides the structure with the ability to “breathe.” When using a double-sided vapor barrier membrane that has identical surfaces, it can be laid on either side. If a one-sided membrane is used to install a vapor barrier, then the reverse side of the material is indicated by the manufacturer.

When purchasing any type of vapor barrier material, be sure to read the instructions for its use provided by the manufacturer.

Basic rules for laying vapor barrier film

After determining which side of the room or insulation you need to lay the vapor barrier material on, you can proceed directly to its installation. In this case, the following rules must be observed:

• First– installation of heat-insulating and sound-proofing material is carried out, followed by a vapor barrier film.
• Second– the film should be well stretched, there should be no sagging areas.
• Third– the vapor barrier material is attached using ordinary adhesive tape (adhesive tape). You can also use nails with a wide head (30 cm pitch) or a furniture stapler as fastening elements, which will greatly facilitate the work and reduce the time it takes to complete it. The film can be secured with wooden slats, which are screwed in increments of 30 cm.
• Fourth– individual sheets of vapor barrier film are overlapped by up to 15 cm. In this case, it is imperative to ventilation gaps up to 5 cm wide.
  This general rules the use of vapor barrier material, but when laying it on different bases and roofs, there are specific features.

Roof vapor barrier

Providing moisture protection to the walls of the house is only 50% of the work, since the bulk of the evaporation is directed upward. The formation of condensation as a result of heavy precipitation cannot be avoided. As a rule, the roof of the house takes the brunt of the impact.

It is also necessary to understand that poor-quality installation of vapor barrier performed on the roof will contribute to a decrease in the temperature inside the house, an unfavorable odor, the formation of dampness, mold, corrosion of metal structural elements, etc. Therefore, it is quite important to use high-quality vapor barrier material and install it correctly.

To protect the roof of a house, experienced roofers recommend using membrane-type vapor barrier materials that allow air to pass through and do not allow moisture to pass through. A membrane vapor barrier will also help remove excess moisture from insulation material. Membranes of a double-sided design will work on both surfaces of the roof covering.

Sequence of materials

When arranging the roof of a house, it is important that the construction materials are in the following sequence:

1. Roof covering
2. Counter-lattice
3. Lathing
4. Waterproofing
5. Rafters
6. Insulation
7. Vapor barrier
8. Roof filing

Vapor barrier is one of the important points when building a house, as it protects the elements of the main structure of the house from mold, rot, rust and other negative influences that help reduce their service life. And also a high-quality layer of vapor barrier will provide optimal temperature regime for a comfortable stay.

Very often, various concepts are confused in the building materials market; even sales consultants can give incorrect information. The names used are waterproofing, vapor barrier, hydrovapor barrier, diffusion membranes, breathable membranes, wind protection, etc.

Water vapor barrier for roofing

How to correctly name materials taking into account their properties and what are their differences?

1. Waterproofing. These materials allow steam to pass through, but do not allow water to pass through. Modern membranes are manufactured using innovative technologies. Depending on the type, they have different vapor permeability indicators, the higher the vapor permeability values, the better performance characteristics. May be called breathable or diffusion membranes. They do not interfere with the removal of steam from the insulation and protect it from condensation drops. Of course, wind protection is also done at the same time.

   Roof waterproofing

2. Vapor barrier. Does not allow steam or water to pass through. Its task is to minimize the amount of steam penetrating into the insulation from residential premises. Accordingly, hydrovapor barrier is the same vapor barrier.

   Vapor barrier of complex roof

Confusion also arises because there is traditional materials(roofing felt, polyethylene film, aluminum foil), which are called waterproofing. But they do not fully correspond to modern membrane water vapor barrier materials. And roofing felt, and polyethylene film, and aluminum foil do not allow steam and water to pass through; from the point of view of modern coatings, they should be called vapor barriers or hydrovapor barriers, which is actually the same thing. And membrane waterproofing allows steam to pass through and allows the thermal insulation of the roofing pie to dry. Such confusion arose due to the desire of manufacturers to advertise their products using all available methods. Developers are attracted by unfamiliar “scientific” names; they buy the most expensive materials, although there are many cheaper materials on the market with the same physical characteristics.

Types of waterproofing

ISOSPAN AQ proff	Moderately flammable and non-flammable material, can work at temperatures -60°C +80°C, roll width 1.6 m, length 43.75 m.	4600 rub./roll.
	Equivalent diffusion resistance 0.03 Sd/m, vapor permeability 1300 g/sq.m/24 hours. Roll width 1.5 m, length 50 m.	7700 rub./roll.
JUTA Yutavek 115	Roll length 50 m, width 1.5 m. Temperature range -40°C +80°C, equivalent thickness of diffusion resistance 0.037 Sd/m. Moderately flammable.	4000 rub./roll.
	There is 75 m2 of membrane per roll, density 140 g/m2. Highly flammable material, can operate at temperatures of -40°C +80°C.	8400 rub./roll.

Types of vapor barrier

ISOSPAN FD proff	Vapor permeability 0 sq.m.h.Pa/mg, use at temperatures -60°C +80°C is allowed. Roll width 1.2 m, length 58 m. Moderately flammable and moderately flammable.	RUR 3,650/roll
JUTA Yutafol N 96 silver	Roll length 50 m, width 1.5 m, density 96 g/m2. Temperature stability -40°С +80°С., tensile strength 210 N. Highly flammable.	1300 rub./roll.
	Equivalent thickness of diffusion resistance 150 Sd/m, highly flammable, moderately flammable. Vapor permeability 3.1 × 10^-6 mg/(m×h×Pa).	9500 rub./roll.
	Vapor permeability 19 g/sq.m/24 h, can be used at temperatures -55°C +80°C. Density 60 g/m2.	1000 rub./roll.
TYVEK AIRGUARD REFLECTIVE	Roll length 50 m, width 1.5 m. Has a reflex layer, diffusion resistance thickness 2000 Sd/m. Can operate at temperatures -40°C +80°C.	RUB 13,400/roll

Why do you need hydro- and vapor barrier roofing?

Unfortunately, even many professional builders intentionally, to increase the estimated cost of work, or out of ignorance, incorrectly use various insulating membranes during roof construction. When, what and for what purposes should steam and waterproofing protection be used?

Non-insulated roofs

Such roofs can have different coatings; depending on their characteristics, a decision is made on the need for additional insulating materials.

1. Roofing made of metal tiles, profiled sheets, asbestos-cement slate, natural or artificial piece tiles.

   Metal roofing does not require vapor barrier

   There is no need to use hydro-vapor barrier under these roofing coverings, although there are often cases when roofers install it under metal tiles and profiled sheets. It's a waste of time and money. The fact is that condensate evaporates without problems due to natural ventilation, and any additional protection only complicates this process. A vapor barrier will never completely protect the coating from steam penetration; there is no way to make the protection airtight; in any case, air will find cracks and enter the under-roof space. If you make a vapor barrier layer, and even without special additional vents, then the operating conditions of the roofing coverings will only worsen, and accordingly, their service life will decrease.

2. Soft roofing coverings.

   Waterproofing is required for soft roofing

   Here it is recommended to use waterproofing as an additional guarantee of the tightness of the coating. The fact is that soft bitumen shingles are laid on a continuous sheathing, the processes of natural ventilation are significantly slowed down. A constantly wet OSB board or plywood loses its original properties. Surfaces become deformed and roof leaks increase even more. To reduce the risk of such negative problems, simple waterproofing is used. It does not allow steam or water to pass through.

Everything is clear with uninsulated roofs, now we should consider more complex types roofing pies.

Warm roofs

These are very popular types of roofs, allowing the use attic spaces for residential attics. Modern materials are used as insulation; depending on their type, certain protective membranes are recommended. How technical specifications Do thermal insulation influence the choice of hydro- and vapor protection?

Styrofoam

This refers not only to polystyrene foam, but also to all its derivatives: expanded polystyrene, penozol, etc. There are quite a few varieties of polymer insulation materials; in terms of their performance, they fully meet the requirements of most developers. It is generally accepted that these insulation materials have two significant drawbacks: flammability and the release of harmful substances into the air. chemical compounds. Is it really? Modern foam plastics do not support open combustion; they melt when the temperature increases, and begin to burn when heated to more than +800°C. For your information, wood ignites at a temperature of approximately +400°C. So, this indicator does not have a noticeable effect on the fire safety of the house.

Using expanded polystyrene as roof insulation

Now a little about the release of harmful substances. You need to know that absolutely all chemical building materials emit harmful compounds in one quantity or another. This includes varnishes used for furniture or flooring, plastic decorative elements and wall decoration, etc. But according to these parameters, they are approved for use by government regulatory organizations; foam plastic also has this approval.

Example of roof insulation

Conclusion - use foam plastic to insulate roofs without any worries. Compared to mineral wool, it has a very important advantage - it does not completely absorb moisture. For a warm roof with foam plastic, there is no need to use steam and waterproofing, and this significantly reduces the cost roofing works.

Mineral wool

A very fashionable thermal insulation material for roofing at the moment. We will not dwell on the advantages; we will point out the main operational disadvantage: mineral wool reacts extremely negatively to an increase in relative humidity. It sharply increases thermal conductivity, heat saving indicators tend to zero. In addition, wet mineral wool significantly accelerates the process of rotting of wooden structures of the rafter system.

Mineral wool reacts extremely negatively to increased relative humidity

For such a roofing pie, it is necessary to use hydro- and vapor barrier. But this should be done with skill, technology errors lead not only to deterioration of microclimate parameters in attic rooms, but also cause destruction of the rafter system, structural elements rot and lose load-bearing characteristics. The roof has to be not only repaired, but completely covered. The cost of such work is much higher than the cost of constructing a new roof covering.

Roof insulation with mineral wool involves the use of hydro- and vapor barriers

TechnoNIKOL stone wool: insulation characteristics

Negative consequences of improperly installed water vapor barrier

Water vapor barrier is installed on the inside of the attic space. Its function is to minimize the amount of steam entering the mineral wool layer. It is impossible even theoretically to make the protection completely airtight.

Attaching the vapor barrier

What consequences incorrect installation water vapor barrier?

1. A sharp increase in the thermal conductivity of structures makes it difficult to maintain comfortable temperatures in the room. Due to the fact that air circulates least in the corners, these areas are considered dead zones. In corners, the temperature of wall coverings often drops below the dew point, and steam condenses on surfaces. Long-term high humidity creates ideal conditions for mold growth.
2. Stains, dirty spots, etc. may form on the finishing coatings of attic ceilings and walls. This indicates more complex problems with an insulating layer of the roof. The reason for the occurrence of unpleasant situations is incorrect choice water vapor barrier or gross violations of installation technology.

   At best, they do not allow water to pass through, and steam freely enters the mineral wool. In winter, condensation periodically freezes/thaws in the upper part of the insulation, water flows down and over time all the mineral wool becomes wet. Water conducts heat well (thermal conductivity increases) and gradually penetrates the surface of the upper finishing of the walls of the room. They have to be repaired or completely replaced. But it is not advisable to make repairs without eliminating the cause; after a short time, the problem will reappear. The only correct solution is to completely redo the water vapor barrier and insulation, and this is time-consuming and expensive.

3. Insufficient thickness of the insulating layer. Unfortunately, often the thickness of the thermal insulation layer does not exceed ten centimeters. Building codes For the Moscow region, they recommend a mineral wool thickness of more than 15 cm; if it is less, then the wool will inevitably freeze, regardless of the quality of the hydro-vapor barrier installation. As a result, the same negative consequences appear as those described above.

   If the thickness of the standing insulation is insufficient, a number of negative consequences will arise

Practical advice. A warm roof is exactly the type of house design during the construction of which it is better to play it safe than to try to simplify existing technologies.

Currently exists big choice of various modern hydro-vapor barriers, their characteristics differ little, but the price varies widely. You can use modern nonwoven materials made using the most innovative technology. But practitioners advise doing something smarter - using traditional, cheap and very effective materials as a water vapor barrier.

1. Polyethylene film. It is better to take a thickness of at least 50 microns; the film perfectly protects mineral wool from steam. The only significant drawback of polyethylene film is a negative reaction to hard ultraviolet rays. Under their influence, the intermolecular bonds of the polymer chains are disrupted, the film loses its plasticity, and cracks under minor loads. Special additives slightly increase the resistance of the material to UV rays, but do not make it completely resistant. There are no problems for the roofing pie; the polyethylene film is completely protected from harmful influence ultraviolet rays, which increases its service life to hundreds of years. Another advantage of this material is that the sleeve width can reach three meters, and after cutting, the size of a single film increases to six meters. This makes it possible to finish most mansard roofs without seams or with a minimum number of them. Fewer joints means fewer points of moisture penetration into the mineral wool layer.

   Polyethylene film

2. Aluminium foil. It is also completely sealed against moisture vapor, but this material has three significant drawbacks. The first is the high cost compared to plastic film. The second is low levels of physical strength. Third, the foil cannot stretch and breaks through with slight vibrations of the rafter system. This complicates the use of the material; in total, in terms of actual performance indicators, it is much inferior to polyethylene film.

   Smooth aluminum foil 150 microns

3. Water vapor barrier based on coatings with liquid rubber or modified bitumen. In the construction of warm roofs for residential premises it is rarely used due to unpleasant odor, but technical or industrial warm rooms can be finished with them.

   Bitumen mastic for roofing

Important. Construction prospects warm roof should be considered at the design stage of the house. This will help you choose optimal sizes rafter legs and the step between them, determine the need for installation and parameters of slats for interior wall decoration attic premises. Another advantage of this approach is that the rafter system is made with a minimum number of different stops and supports, thereby reducing the number of points of probable depressurization of the protective layer.

How to properly install hydro-vapor barrier

A very important point when building a warm roofing pie. Water vapor barrier is designed to limit the penetration of water vapor from the living spaces of the attic into the thickness of the mineral wool. We have already mentioned above that it is better not to insulate the roof at all than to do it incorrectly. Practice shows that if technology violations are critical, then the rafter system will have to be repaired in 7–10 years. What is a warm roof repair? This includes dismantling roofing coverings, waterproofing (vapour-permeable wind protection), and removing thermal insulation. Next, you need to go inside the premises, remove the external wall decoration and water vapor barrier. The last stage is a revision of the rafter system and replacement of failed load-bearing elements.

How should you make a roofing pie to avoid such problems?

Step 1. Carefully inspect the material and place it correctly. All inscriptions should be facing the room, and not vice versa. You need to start laying the water vapor barrier layer of the pie from the ridge part. Roll out the roll so that it is located in the middle of the structure. You need to work on a stepladder and with an assistant. Roll out the roll in parts, making preliminary fixations every 1.5–2.0 m. The final one should be performed only after the material is completely leveled, there are no folds or kinks.

All signs must face the room

Step 2. Secure the water vapor barrier with a construction stapler, the distance between the staples is approximately 25–30 cm.

Fastening the blade

Important. There is no need to nail the staples too often; this will only increase the number of holes. Lightweight material, fixed without problems.

It is advisable to install thermal insulation after covering the roof. During roofing work, it is necessary to lay out a vapor barrier (wind barrier) and secure it with strips. Then put a counter-lattice on the slats, it will provide ventilation of the under-roof space, condensed water will be naturally removed. Roofing materials laid after preparing the vapor barrier layer.

Some builders do the opposite, first installing a water vapor barrier inside the premises, and then laying insulation and covering the roof. This order of work cannot be considered optimal. The fact is that if mineral wool gets wet due to precipitation, it will have to be removed and dried. This greatly complicates the construction of a warm roof and deteriorates its quality.

Step 3. The second layer is rolled out parallel to the first; you should gradually move down towards the cornice. After alignment, secure the membrane with staples.

Step 4. Very carefully seal the junction of the water vapor barrier to the chimneys.

The junction of the water vapor barrier to the chimney

Use special sealing tape for this; never buy low-quality additional materials. If the adhesive tape has insufficient adhesion characteristics, then after a short time it will peel off, and a large gap will form between the surface of the chimney and the water vapor barrier. It is impossible to notice it in time due to finishing interior walls, and the appearance of visible condensate leaks will require complex repairs.

Step 5. The overlap between the rows should be within 10 cm, glue them carefully.

The overlap between the rows is taped

Experienced builders advise first nailing small slats to the rafters in these places. For what? Firstly, they will create a gap between the mineral wool and the hydro-vapor barrier, which will improve the conditions for removing trapped moisture. Secondly, if there are slats under the overlaps, then you can press the tape firmly, the sealing will be more reliable.

The slats are nailed down

Practical advice. When installing the insulation, take measures so that it does not rest against the water vapor barrier. Mineral wool must be fixed in the space between the rafters. This can be done with a rope made of synthetic materials, metal profiles or wooden slats. The fact is that mineral wool bends and sags a little over time under the influence of gravity. Unforeseen forces begin to affect the water vapor barrier, it bends, and the sealed joints become depressurized.

Roof insulation

A roll of vapor diffusion membrane is rolled out parallel to the ridge

The overlap between the vapor diffusion membrane sheets is 10-15 cm

Fixing the canvas

Sealing the joints of the vapor diffusion membrane with self-adhesive tape

Organization of the ventilation gap

There are 10 cm gaps in the bars every 2 meters

The membrane is secured with slats

After completing the work, you need to carefully inspect the roof surface again and correct all detected problem areas. Particularly carefully monitor the connection of the water vapor barrier to various pipes and other engineering structures. Experienced builders recommend finishing them with any silicone sealants before fixing the membranes. They will completely fill the seams in masonry building materials and improve the quality of water vapor barrier. And this, as already mentioned, plays a decisive role in the longevity of operation and the heat-saving efficiency of buildings.

Video - Water vapor barrier, insulation, roof waterproofing

One of the most difficult tasks in construction is waterproofing buildings. The main protection of waterproofing is to protect the roof from rain and capillary moisture. It is especially worth paying attention to how to lay the insulation, and make sure which side all the materials are placed.

Waterproofing material is designed to protect not only the building from moisture, but also the insulation, thanks to which it will last much longer.

Waterproofing not only protects the building itself from water penetration inside, but also protects the insulation, which affects its properties. When wet, insulation loses its heat-insulating properties, which can lead to its destruction. Water that penetrates into the premises will also negatively affect the appearance of the building.

First, it is worth understanding that waterproofing and drainage are not mutually exclusive concepts.

Before building a foundation, walls, etc., you need to take care of drainage, especially if the house is located in places where water accumulates or there is high groundwater.

Secondly, it is worth choosing waterproofing materials based on climatic conditions, as well as depending on the area.

The waterproofing of the building must be thought out at the design stage; if not thought through, it will lead to additional costs that are not comparable to those that will occur during construction and re-installation of all materials.

Waterproofing can be very different: coating, plaster, polymer, penetrating, injection, roll.

Insulation using roll and sheet materials

Pasted waterproofing is sheets or rolls, the base of which is made of moisture-resistant mastics.

Depending on what type of waterproofing is chosen, it must be installed correctly.

Pasted waterproofing consists of rolls or sheets in which special layers of waterproof mastics are applied to the base. The most common and most familiar materials are roofing felt, glassine and roofing felt. Based on the fact that these materials are cardboard based, it should be taken into account that they can only be applied to horizontal surfaces.

The adhesive waterproofing must be placed with the side facing the hydrostatic pressure, sandwiched between the protective coating and the structure that is being insulated.

However, this type has a number of significant disadvantages: it is not resistant to rotting, short-lived and poorly resistant to water. It is difficult to lay on the roof; it requires thermal preparation. And in a torrential downpour, the roof may drip, unable to withstand the pressure.

Waterproofing work should be carried out in several stages:

• initially apply a primer;
• the soil layers are dried;
• if necessary, putty is applied and it must be dried;
• paint layers are applied and these are also dried;
• The coating is subjected to heat treatment or exposure.

Emulsion-mastic compositions must be placed hot, for this the following technical requirements must be observed. Bitumen insulation must be heated to 180 degrees. It should be no more than 20 mm thick with an intermediate layer of 1.5 mm.

Scheme of the main surface waterproofing coatings

When applying tar, the temperature range is within 130 degrees plus minus 10 degrees, with the thickness of all coatings being the same as for bitumen. The work must be periodically inspected and measurements taken at the control area and recorded in a log.

Before laying the roof with roll insulation, it is necessary to level the surface; unevenness should not exceed 2 cm.

This type of roll insulation also includes paint insulation, which is optimally suited for vertical surfaces.

Bitumen-polymer modified waterproofing

This type of waterproofing is used for both the top and bottom layers of the roof, as well as for leveling. There are two types: one-sided and two-sided. This type of waterproofing differs from the usual roofing felt in its resistance to rotting due to its non-rotting base. They are produced on the basis of non-woven fabrics, fiberglass and fiberglass, elastic polyester bases.

The advantages of this type of insulation include high service life, wide temperature Range, in which this material can be used: it varies from -25 to +30 breasts. High resistance to hydrostatic pressure, resistance to aggressive environment, low water absorption. High speed installation, due to its simplicity and the ability to lay on uncured concrete.

Before carrying out work using the free-laying method, the surface must be cleaned and dried. There should be no precipitation or puddles at the work site. It is necessary to remove all oil stains and traces of cement; for this, use a sandblasting unit. It is necessary to ensure which side the waterproofing is laid.

Before work, the material is allowed to rest so that it takes on its dimensions.

This type of waterproofing is characterized by a long service life and a wide temperature range.

Tools required for working with roll waterproofing:

• gas torch for welding longitudinal and end overlaps;
• rolling roller, used in case of insufficient flow of bitumen mass from the seam;
• bandage tapes or special strips at least 20 cm wide;
• self-tapping screws or dowel-nails with a fastening pitch of 25 cm.

Waterproofing film

It applies to any construction work and is the most durable, can withstand direct hydraulic pressure. The most durable of all films is perforated and flat.

Perforated film is thick, brown, gray or black, has perforated cells in the form of cones or parallelipids. It is placed on the floor or wall in cells with the side on the protected surface. It is used for both vertical and horizontal insulation, in places of increased water accumulation, for the installation of “green” roofs.

Flat film does not differ in appearance from ordinary garden film, but is much stronger and more resistant to aggressive environments. It is used for moisture protection of walls in the basement, foundations, and comes in black or dark gray.

This film is used when constructing a floor on the ground; in this case, it is placed under a layer of foam-based insulation. When insulating a floor with mineral fibers, the film is placed on the material, then a layer of flooring is laid.

This type of film is used for waterproofing bathtubs, since tiles cannot guarantee impermeability from water, which accumulates in the seams, which manifests itself in dampness of the walls.

Under-roof protection

Under-roof insulation is carried out using a variety of types of waterproofing materials.

Most main advice Something worth remembering is how to properly install waterproofing. Be sure to place it glossy side up. Otherwise, condensation will accumulate and drain into the room, which will lead to inevitable re-laying of the material, and this cannot be done without dismantling the entire roof. Therefore, the operation of the house and its final cost depend on which side it is laid.

It is best to fasten waterproofing material under the roof using galvanized nails with a wide head.

If you are placing special materials, you must do this in the following order:

• a film is placed on the heat-insulating material;
• a film is pulled over the ridge of the house or edge with an overlap of at least 20 cm, with the glossy side up;
• We nail the counter-battens and fasten a strip of polymer film on top.

When installing dormer window Place the film on the window frame and secure it. The width of the film placed on the window frame is no more than 5 cm. The joint must be completely sealed. Flexible corner elements installed to drain water onto the roof.

The under-roof insulation is installed using a stapler or nails with a wide galvanized head. Counter-lattice bars with a cross section of 40 by 25 mm are nailed on top of the film.

Water should not be allowed to drain onto the insulation; additional insulation is required at the intersections with structural elements penetrating inside.

Insulation protection

It can be of two types: simple and with anti-condensation action. In this case, there are polyethylene, polypropylene and non-woven breathable ones. Polyethylene films are used for both vapor barrier and waterproofing.

Non-perforated films are used to protect against water, and perforated films - against steam.

There are a large number of modern materials that can protect insulation, for example, membrane and roofing films, reinforced mesh or special fabric. They must be laid with the right side facing the insulation, otherwise, instead of protection, the insulation will be destroyed.

Diffusion membranes must be laid on the insulation itself, this will save space and reduce unnecessary costs. The strength of membranes is much higher than that of films. We must not forget that membrane materials are one-sided, and the normal functioning of the entire roof structure and the insulation itself will depend on which side you place it on.

There are membrane films with cone-shaped holes, which are located so that steam and water come out rather than being trapped inside.

Place the insulation between the hydro- and vapor barrier, in this case the reflective surface of the vapor barrier, fixed from the inside of the under-roof space, will function well. When using polyethylene or polypropylene films, a gap is needed for ventilation; in this case, install drywall.

You cannot skimp on materials, and it would be good to supervise the workers when it comes to waterproofing.

It is difficult to underestimate the importance of such a stage in the construction of a house or other structure as vapor barrier. This term means various ways and means designed to exclude or minimize the penetration of moisture in the form of condensation into structural materials. It is important to determine which side to lay the vapor barrier on, and the tips or instructions below will help with this.

Insulation materials are the most vulnerable to moisture. Under the influence of moisture, the structure of most modern insulation materials, and as a result, they fall or disappear thermal insulation properties. However, this is far from the only threat posed by condensate penetration. In a humid and closed environment, fungal organisms, that is, mold, which is completely unnecessary there, begin to actively develop. They negatively affect the reliability and durability of load-bearing structures, especially wooden ones.

Vapor barrier material options

The modern building materials market has a wide range of vapor barrier coatings. They are divided according to many characteristics, primarily by vapor permeability, which is needed to select the location for installing the insulation. Also, vapor barrier materials have a fairly wide price range, which should also be taken into account when choosing a material.

The main types of vapor barrier are:

1. Traditional vapor barrier film;
2. Film with a layer of aluminum foil;
3. Membrane film.

Unfortunately, there is no material that is equally acceptable for any area of ​​vapor barrier, be it a roof, walls, one of the floors, or a foundation. Therefore, it is extremely important to take into account the structure of the materials being coated, the purpose of the insulation and the area of ​​coverage, and based on this, choose the right specific material, as the instructions will tell you.

In addition, it is necessary to take into account the characteristics of each type of vapor barrier. If a vapor barrier film made of polyethylene is installed, it would be correct to leave gaps, because in addition to insulation from steam, the film is completely airtight, so condensation will form in a closed structure without air access.

Features of membranes

Membranes, in addition, are divided into pseudo-diffusion, diffusion and super-diffusion. They differ in vapor permeability coefficient, which is 300 g/m2, 300-1000 g/m2 and more than 1000 g/m2, respectively. Based on this characteristic, the suitability of membranes for insulating certain structures is determined. Pseudo-diffusion practically does not allow moisture to pass through, and is most suitable for vapor barrier of the outer layer under the roof. However, an air cushion is needed between the film and the insulation. And such films are completely unsuitable for insulating facades. The pores of the membrane become clogged with external dust, and condensation begins to remain directly on the material.

The remaining types are more versatile due to their larger pore diameter. This makes it difficult to clog them and allows you to avoid leaving air gaps.

Correct placement of material

A key role in achieving good insulation of structures is played by which side to lay the vapor barrier. The answer to this question also depends on the chosen vapor barrier material:

1. Vapor barrier polyethylene film is laid with either side facing the insulation, but there are special vapor-condensate films with roughness for better evaporation of condensate. In this case, the film is placed with its smooth side facing the insulation. Such details are usually determined by the attached instructions.
2. Laying a vapor barrier from a diffusion membrane, by analogy with a vapor-condensate film, is done with the smooth side facing the insulation.
3. Materials containing energy-saving foil should be correctly mounted with the foil side facing the inside of the room, because it reflects heat.

It is important to consider the following features:

1. Vapor barrier material, whether it is rolled or sheet, is laid only overlapping and secured with special tape that prevents the passage of air in the gaps.
2. Under no circumstances should damage (breaks, cuts) to the insulating material be allowed, even if they were formed during the process or after installation they must be sealed.

DIY vapor barrier

Vapor barrier of a room is a procedure that can be done with your own hands. If you take into account the above rules, correctly determine which side the insulation is laid on, and choose the right material, then even without the help of professional builders, it will be done reliably.

The most indicative would be a do-it-yourself floor vapor barrier. Before installing insulation and vapor barriers, it is strongly recommended to treat underground structures with compounds against wood rot and against insects. Special meaning This treatment is used for structures closest to the ground and foundation. After this, the logs are installed, and the subfloor of the first floor floors is mounted on top of them. This will be the basis on which the floor vapor barrier is laid.

The selected vapor barrier material is laid on top of the subfloor, with an overlap of 15–20 centimeters. It can be secured with nails or a construction stapler, but the most correct would be the previously mentioned adhesive tape. Places that are difficult to reach, abutments to walls and raised areas of floors, require additional treatment with bituminous material, because it is almost impossible to properly lay film in such places. After laying the vapor barrier, the installation of thermal insulation begins. It is important to lay these materials (mineral wool, polystyrene foam and others) close to the joists.

The vapor barrier of the floor, however, does not end there. Moisture can get into the insulation from inside the house from the first floor. Therefore, when insulating, you need to lay another layer of vapor barrier, similar to the bottom layer. Any type of membrane insulation is most suitable for this purpose. This layer is also overlapped. You can confidently lay the main floor on top of it. In this case, you need to leave 1-2 centimeters as a gap.

Conclusion

With the correct choice of side, which insulation is laid to the insulation, as well as the correct choice of the vapor barrier material itself, reliable vapor barrier of the floor will be ensured. And it, in turn, is one of the important components of the overall reliability and durability of buildings.

Laying waterproofing, its features, choice of materials for its implementation

Important features when laying hydro- and vapor barriers must be taken into account when building any structures, otherwise inattention at these stages can lead to disastrous consequences during the operation of the house

Which side to lay the waterproofing film

Proper waterproofing of a building is one of the most difficult and critical stages of construction or renovation.

If the waterproofing material is laid incorrectly, then within six months the residents of the house will be able to observe an unpleasant picture in the form of:

• high room humidity;
• getting the insulation wet, which will very soon collapse from such exposure;
• poor heat retention inside the house due to a wet insulating layer.

To avoid the above problems, it is initially important to lay the waterproofing correctly, namely on the side recommended by the manufacturer. Below we will answer the question of which side to lay waterproofing under different types of building materials and in different parts of the building.

Under metal tiles

Under the layer of metal tiles, the waterproofing film is laid with the markings up, horizontally from the ridge to the eaves, with an overlap of 15 cm. The film should only be attached to the joists or rafters using a stapler. It is important to remember about the film sag, which must be under the metal tile layer (about 2 cm). It will help air circulate freely and protect the film itself from premature destruction.

Waterproofing floors in rooms such as bathrooms and kitchens requires maximum precision in laying the moisture barrier layer. In this case, the waterproofing film is attached with the unmarked side to the insulation.

The roof waterproofing stage begins with laying insulation. Then a waterproofing film is spread over it in an even layer at the joint. The film is laid with the logo facing up, with the adhesive layer directed towards the insulation. Be sure to take into account the ventilation gap for normal air circulation between materials.

To waterproof walls inside the house, the film is mounted with the logo facing up, with the unmarked surface facing the insulation.

Laying the waterproofing film on the walls outside the house is carried out on the insulation, with the markings facing up. The film is secured with a construction stapler with an overlap of 15-20 cm.

To the ceiling

Waterproofing films are laid with the unmarked side facing the insulation layer or the ceiling.

Properly laid waterproofing is a guarantee of long service life of the insulation. Keep this in mind and take into account the recommendations of the manufacturer of waterproofing films during repairs and/or construction.

Which side to lay the waterproofing film

Which side to lay the waterproofing film on? Proper waterproofing of a building is one of the most difficult and critical stages of construction or repair. If the waterproofing material

Which side is the correct way to lay a vapor barrier in a house?

The tendency to insulate everything has led to the fact that most people absolutely do not understand why a vapor barrier is needed in a house. Well, let's try to find out.

So, the air humidity in any living space is higher than outside - because of this, steam is formed. In the summer, it freely escapes through the ventilation system and a layer of insulation, but in the winter, a phenomenon is observed that people say “the walls are crying.”

Vapor barrier concept

This happens when steam does not find a way out and condensation settles in the walls or on the ceiling. As a result, the walls become damp, mold forms on them, and the thermal insulation material becomes saturated with moisture and completely loses its protective properties. Prolonged contact of walls with moisture will lead to cracks.

To avoid such a situation, when repairing or building a house, it is necessary to add a vapor barrier layer to the insulation to eliminate any possibility of steam or moisture getting into the thermal insulation layer, as well as walls and other structural elements of the house. After all, all walls are susceptible to moisture formation, and not just the insulating layer, since steam accumulates along the entire perimeter of the home, which separates the warm zone from the cold one. This includes basements and roofs, if they are not heated.

Vapor barrier materials

The cheapest and short-lived materials for vapor barrier are glassine or polyethylene. But they have long since become a thing of the past, and modern materials have replaced them:

Roofing membrane options

1. The membrane is perforated. Small holes are pierced in it and moisture comes out through them. The vapor permeability coefficient is very low, so this material is used only as an under-roof vapor barrier for a cold sloping roof. After all, during frost, steam will settle directly on the membrane, which will significantly reduce its vapor permeability.
2. Porous membrane. The structure of this material most closely resembles a filter due to the presence of pores between the fibers. Steam seeps through them. Accordingly, the coefficient of vapor permeability is determined by the size of the pores and the moisture-repellent properties of the walls. But if environment heavily contaminated, in particular with dust or exhaust gases, the pores become clogged and the vapor permeability of this material is significantly reduced.
3. Three-layer superdiffusion membranes. The most reliable material, where each layer serves to perform a specific function. This membrane has no holes, so dust or wet sediment will not damage this material. The three-layer membrane is perfect for urban environments and also performs excellent vapor permeability and moisture protection functions.
4. Double-layer film membranes. Used over insulation. This is a relatively inexpensive replacement for a three-layer vapor barrier. The absence of one protective layer slightly impairs the reliability of the membrane; this material is used for internal vapor barrier of roofs and walls.

Tools

Vapor barrier materials are quite easy to damage, which should not be done under any circumstances, since if the film is damaged, moisture will penetrate into the insulation and over time it will completely lose its protective properties.

During installation, wooden slats, sublattices, or a metal, galvanized profile are used. The material is secured with self-tapping screws, staplers or nails.

If the vapor barrier layer is thin, for example, a regular film, then you can use tape; it reliably connects the joints.

Work process

Floor vapor barrier

Performed directly in the premises on the ground floor. This operation is also carried out for rooms where humidity is significantly increased.

First, you need to carry out waterproofing - this is a set of protective measures against the harmful effects of water. Waterproofing is laid on the cement screed. For floors and walls, a coating material is more suitable - a special moisture-resistant substance that is applied in several layers to structural elements to prevent corrosion or other harmful effects of water.

A layer of insulation is laid behind the waterproofing layer, and it is covered with a one-inch thick board. A vapor barrier layer is laid on top of the board.

When the main material is film (perforated, polyethylene), it is secured with double-sided tape so that it does not sag.

Since a vapor barrier is necessary to prevent condensation from getting on the insulation, how to properly lay the material with the smooth side outward, then it will stop any moisture.

The same should be done with a vapor barrier, which is covered with aluminum on top; the shiny side should be in the room to retain moisture, and the rough side should be applied to the insulation.

The vapor barrier is always overlapped. The distance between the joints should be 15 cm. It is glued together with tape or special tape, and then secured with a stapler to the board that is located under it.

The best way to vapor barrier a floor is to use liquid rubber made from bitumen. How does it work? Liquid rubber applied on top of the boards. When it dries, it becomes an elastic waterproof film that is very well glued to the floor and does not allow moisture to pass through.

Vapor barrier of walls

There are two types - external and internal vapor barrier. The process itself is almost completely similar to the previous one.

For internal vapor barrier, a vapor barrier film is attached along the entire perimeter of the wall using a stapler or galvanized nails. The question often arises of how to properly install a vapor barrier. If the contents of the vapor barrier contain foil, then its shiny edge is located inside the room. When using foam propylene material, the rough side is applied to the wall.

The canvases are laid horizontally, starting from the bottom. The joints must overlap, and then, for reliability, they are glued with tape or mounting tape. Galvanized profiles are mounted on top, on which drywall is then laid. There must be ventilation gaps between the drywall and the vapor barrier.

External vapor barrier is a set of measures to protect insulation from harmful effects external environment, which can come from both outside and inside, through damage to the wall covering.

To protect the insulation from the outside, it is necessary to use a wind-moisture-proof, vapor-permeable membrane, strong enough to protect the walls and insulation from wind and moisture, but with the ability to release steam out of the fiber insulation.

This material is laid starting from the bottom, along the outside of the insulation. The rough structure allows steam to pass through, so it should be laid correctly against the insulation, and the smooth, water-repellent side should remain outside.

They are mounted on a wooden frame with an overlap, there should be at least 15 cm between the joints. And then they are secured with a construction stapler. Wooden slats are installed on top of the covering, which carry the outer skin.

Another feature of the water-repellent material is that the lower edge serves to drain the flowing moisture to the basement drain of the building, otherwise the foundation may sag.

Roof vapor barrier

This is also done both from the outside and from the inside.

If the roof is insulated with special thermal fiber, then to protect against negative influence external environment, a two-layer vapor-permeable membrane is used. The top layer reliably protects the insulation from snow, wind and moisture, as well as in places where the roof is defective. The internal vapor-permeable layer of the membrane allows for unhindered removal of under-roof condensate.

The material is rolled out horizontally relative to the roof slope, and then secured to the rafters using a stapler. In this case, it is necessary to correctly lay the vapor-permeable membrane rough side to the insulation. After all, the smooth side provides a water-repellent effect.

Wooden slats 4-5 cm thick are fixed on top using nails or self-tapping screws. The slats create a ventilation effect, which is necessary to ventilate condensation that forms when steam collides with the cold surface of the roof. Then a lattice of wooden beams is mounted along the slats or, if required by the type of roof, a solid plank flooring on which it is attached upper layer roofs.

For non-insulated roofing, a three-layer superdiffuse membrane is used. It protects each structural element, as well as the attic itself, from steam and condensation formed by it. In addition, the three-layer membrane retains moisture from negative atmospheric phenomena penetrating through roof damage, such as:

Mounted on wooden slats without taking into account the side. Lay it horizontally with an overlap. They are fixed on top with slats to ensure ventilation, then the roofing condensate will evaporate correctly.

The vapor barrier of the roof from the inside is done using a two-layer film. We must not forget that the smooth side provides protection from moisture, and the rough side retains drops of condensation until they evaporate. Therefore, it is correct to lay such a vapor barrier with the rough side facing the ceilings, the smooth side should go out.

Vapor barrier is an excellent way to extend the life of the external enclosing structures of the house, as well as protect the insulation layer from moisture that occurs through condensation or water that penetrates through damage to the external finishing layer or through damage in the roof.

Which side to lay the vapor barrier and waterproofing towards the insulation, instructions for correct installation materials

What is vapor barrier. What materials to use for vapor barrier. How to lay it correctly, which side. Process description.

Which side to lay waterproofing on?

Often waterproofing is installed water-repellent side in the direction from which moisture can penetrate. For example, roof waterproofing is laid on top of the insulation with a water-repellent layer facing up. And on the floor and walls, the water-repellent layer is directed away from the insulation, while waterproofing can be used both inside and outside the building.

How to determine the water-repellent side for different types of waterproofing:

Which side is the waterproofing placed on the floor?

Depending on which side protection from moisture is needed, the waterproofing spreads:

• water-repellent side down - when laying under moisture-absorbing insulation on concrete or earthen floors;
• water-repellent side up - directly under the screed to protect floors in very wet areas.

Which side to lay waterproofing on walls

The principle of waterproofing walls is the same as that of floors. If you need to protect the insulation or walls from an internal source of moisture, the waterproofing is attached inside with the water-repellent side facing the room. And to protect the walls from the outside, the moisture-repellent layer should be directed towards the street.

Which side is the waterproofing placed on the roof?

The water-repellent side of the roof waterproofing should be directed outward from the insulation. After all, with its help, the insulation is protected from moisture penetrating from the outside - when precipitation or condensation forms under the roofing. The rough side should absorb moisture from the insulation and evaporate it.

Which side to lay waterproofing under metal tiles

Due to its characteristics, metal roofing (made of corrugated sheets, metal tiles) requires special waterproofing - special anti-condensation films. This is the only type of waterproofing that is attached with the fleecy side facing out. It is thanks to the moisture-absorbing outer layer that the metal roof is protected from corrosion - all absorbed moisture quickly drains away without lingering.

Do you need waterproofing on the ceiling?

The ceilings in the rooms are covered only with vapor barrier; waterproofing on the inside of the rooms is not used even in the bathroom or sauna. Otherwise, the interior decoration will regularly get wet - after all, the waterproofing will remove condensation from the insulation into the room.

Which side to lay the waterproofing on: towards the insulation, correctly

How to correctly and which side to the insulation you need to lay waterproofing and waterproofing film: on the floor, ceiling, roof and walls. Answer from construction experts.