How to properly make a roof vapor barrier: technological principles of vapor protection. Vapor barrier for the roof: which side to lay correctly How to lay a vapor barrier on a roof with insulation

When arranging a roof, several layers of different materials are needed. That is why this design is called a roofing pie. If you want your roof to serve you for a long time, you need to use materials for heat, hydro and vapor barrier.

Why do we need a vapor barrier, what is the point of protecting the roof from steam?

Waterproofing and vapor barrier layers consist of completely different materials.

Their differences are that waterproofing protects the house from moisture from above, and vapor barrier prevents vapors from entering the roof structure.

The need for vapor barrier is due to the fact that steam rises from below, from the living space, which enters the “roofing pie”. Thermal insulation material absorbs moist air, swells, becomes damp and becomes unusable. Wooden roof structures also begin to rot over time, fungus and mold form on them, which can lead to complete destruction of the roof.

Vapor barrier is also important for maintaining a favorable microclimate in the interior. If the steam rising from the living rooms does not leave the house, then the inside will always be humid and stuffy. Remember how you feel in a greenhouse - your home can turn into something like a greenhouse without a well-equipped vapor barrier layer.

In winter, a vapor barrier layer prevents ice from forming on the roof. On hot summer days it will help keep the house cool. However, it should be taken into account that for the vapor barrier to function properly, it is necessary to have a ventilated roof.

Do you need a vapor barrier under the corrugated roof of a cold roof?

Many people believe that installing a roofing pie in general and a vapor barrier in particular should only be done for warm roofs where the attic or attic will be located. But modern cold roofs made of corrugated sheets also need vapor barrier.

The fact is that the temperature inside the room, even if it is not heated, differs from the outside air temperature, so condensation will still accumulate on the inside of the corrugated sheets.

The vapor barrier layer will protect against unwanted moisture from entering roofing structures that are susceptible to rotting and deterioration. They fasten the film with lathing, and only then install the roof from profiled sheets.

What materials to use

Roofing materials can be divided into hydro- and vapor barrier materials, and antioxidant ones are also distinguished. Basically, these are film materials based on polyethylene. Recently, a variety of building materials have appeared for all layers of the roofing pie. And if previously only glassine could be used for vapor barrier, now the choice in construction stores is very large. Glassine is practically not used; although it costs less, it is inferior in performance to modern analogues.

There are several main groups of modern vapor barriers:

1. Based on polyethylene. The film can be perforated or non-perforated, the latter is used for the waterproofing layer. The perforated material, despite the presence of holes in it, reliably protects against unwanted moisture. The holes are microscopic, so drops simply cannot leak through them. But steam passes through the perforation perfectly. Another option for polyethylene is foil film. It not only provides steam removal, but also retains heat. If you lay it with the foil side down, it will reflect the heat back into the house. When installing, it is advisable to reinforce any film with mesh.
2. Based on polypropylene. Compared to the first option, polypropylene film is much stronger. Due to the presence of a layer of special fabric, polypropylene film has antioxidant properties.
3. Membrane. This is a relatively new material that is ideal for roofing. The breathable properties of the membrane allow you to save on ventilation. The material does not allow moisture to pass through, but steam penetrates inside, settles on a special fabric layer and dries there. Membranes, or diffuse films, can be single- or double-sided. The method of laying them on the insulation depends on this.

When choosing a material for vapor barrier, you should pay attention to the following properties:

• High strength. Even with significant mechanical impact, the vapor barrier should not be damaged. For example, the material must withstand the weight of vapor and waterproofing if the integrity of the sheathing is damaged.
• Easy to install. This is especially true for those who perform installation work on their own. If the film breaks during the process, is difficult to lay and is inconvenient to unwind from a roll, then it is unlikely that you will be able to make a good vapor barrier.
• Good elasticity. This quality is important when fixing the film. When using fasteners, the film should not tear, but should stretch and tightly grip the screw.

How to install a vapor barrier on a roof. Step-by-step instruction

The vapor barrier layer is part of the roof, an important element of its arrangement. The first stage of installing a vapor barrier is preparation. The under-roof part should be thoroughly cleaned of dust and dirt; it is especially important to dry it thoroughly. Then you should lay the insulation, which always precedes the vapor barrier layer. The installation itself is carried out in several stages:

1. A roll with a vapor barrier film or membrane is unrolled directly at the installation site. If the roof is gable, installation begins from the bottom up, and then, after passing the ridge, goes down again. The film must be overlapped to prevent the appearance of cracks and gaps. Secure the material with tape around the perimeter and at the joints. (Read also: Do-it-yourself installation of a gable roof rafter system)
2. Next, you need to more carefully secure the vapor barrier material under the roof. To do this, use nails or screws with wide heads. Another option is a construction stapler. If you choose good material, it will not tear. The elastic film will close around the fastener. (How to choose the right self-tapping screw, read this article)
3. If you are installing a rough version of the roof, then before installing the vapor barrier layer you should make a sheathing. You can use wooden or plastic slats or a metal profile for it. The film is carefully stretched and attached to the sheathing using self-tapping screws or a construction stapler.

When installing a vapor barrier layer, it is important to follow the manufacturer's recommendations. Many materials have special perforations, so it is important to lay them on the correct side.

If you are installing a roof for the first time or have never worked with modern vapor barrier materials, professional advice will help you avoid the most common mistakes.

• Regardless of what type of roof you are installing, installation of a vapor barrier is carried out only after laying the insulation.
• When installing overlapping film sheets, they must cover each other by at least 10 cm.
• It is imperative to glue the joints with adhesive tape/adhesive tape; moreover, it is better to use a wide tape, at least 10 cm wide. The best option is to use double-sided tape, which is glued inside the overlap. First glue it onto the bottom layer of film, then glue the top layer on top.
• When using nails or self-tapping screws as fasteners, galvanized products are preferred. They are not subject to corrosion, which will extend the life of the vapor barrier.
• If there is a window or hatch in the roof, then it is necessary to use a special apron, which is sold complete with vapor barrier materials. If there is none, then the perimeter of the window or hatch should be covered with butyl tape.
• Also, when working with windows, you should leave a deformation margin around them. Over time, any house, even one built a long time ago, shrinks. This can damage the vapor barrier, which is why a fold of at least 20 cm is necessary.
• If installation is carried out near heating pipes or water pipes, then the vapor barrier material should be carefully wrapped around the pipe and sealed tightly.

The main rule when installing a vapor barrier is to ensure tightness. If the tightness is broken, then the effectiveness of the vapor barrier layer will be minimal.

The main errors in installing roof vapor barriers are noted in the video

Thus, a vapor barrier device is a necessary condition for the long-term operation of the roof of a house. it is necessary both for a warm roof with an attic or attic, and for a cold one.

Heat conservation is not only a component of saving. First of all, it is health and comfort. Excess moisture combined with cold air leads to the formation of dampness and mold. Being in a room where fungus has appeared is not only uncomfortable, but also unsafe. In addition, this leads to the inevitable destruction of building structures that are constantly exposed to moisture. A modern, reliable vapor barrier for the roof will help avoid the above problems.

The level of dryness, comfort, and heat retention in the room largely depends on the condition of the roof. It acts as a barrier between the cold external environment and the internal heat of the building. The use of insulation in the absence of waterproofing for the roof is ineffective. Waterproofing prevents the penetration of steam from the living space into the insulating layers.

For a long time, ordinary polyethylene film was used as a vapor barrier when constructing roofs. But this material is mechanically vulnerable. In addition, it is characterized by a fairly high level of moisture permeability. Modern vapor barrier film for roofing has a vapor permeability of 0.4 g/m², and ordinary polyethylene - 13-20 g/m². It is used for all types of roofs: flat, pitched, and when constructing an attic floor. Reliable vapor barrier of the ceiling is especially important in a cold attic.

The vapor barrier is one of the components of the “roofing cake”, which also includes waterproofing and insulation. If the “pie” is laid correctly and from high-quality materials, then the main functions of the vapor barrier can be considered:

• maintaining the microclimate, ensuring air exchange, maintaining optimal temperature conditions and humidity levels in the premises of the building;
• protection of the roof structure from penetration of moisture from the outside and steam from the inside, preventing the formation of condensation, damage, fungus, mold;
• reduction of heat loss during the cold season, which helps to save costs on coolants;
• increasing the fire resistance of roof structures;

• reducing the cost of repairing the roof and building.

The absence of implementation of at least one of the above functions indicates poor quality of the film or errors made during its installation.

Helpful advice! Before purchasing a vapor barrier material, it is necessary (if you lack knowledge) to consult with an experienced roofer. Incorrect selection may result in steam damage to the insulating material.

Types of vapor barrier and their features

Modern vapor barrier films, actively displacing simple polyethylene, roofing felt, glassine, are distinguished by a wide range and purpose. The most common types, available in price and installation method:

• standard vapor barrier film. It prevents condensation from forming on the roof and insulation;
• foil vapor barrier. Unlike the standard layer, it has a reflective function and provides an increased vapor barrier, and also reflects and returns some of the heat to the room;

• membrane film. It has an insulation effect and limited vapor permeability, which allows you to control the removal of excess moisture from the room.

The vapor barrier film can be made of polyethylene or polypropylene. Polyethylene is a fragile material, therefore a polyethylene product is reinforced with a special fabric or reinforcing mesh. Polypropylene films are a woven material laminated on both sides with the finest polypropylene. This type of product is durable and resistant to ultraviolet radiation.

There are options when an antioxidant layer is applied to the polypropylene film, which absorbs and retains moisture, and after the steam stops flowing, the layer dries through ventilation. A vapor barrier device of this type allows it to be installed in only one way: the rough antioxidant layer is placed at the bottom, the smooth surface at the top.

Films laminated on one side with a foil layer are distinguished by the highest vapor barrier qualities and are the most suitable type of vapor barrier for the ceiling of rooms with high humidity (baths, saunas, swimming pools, etc.).

Types of membrane films

A special type of vapor barrier is under-roof membranes. This is a durable, temperature-resistant material. It does not have low vapor permeability, but is effective in the construction of certain types of roofs. It is characterized by a more complex structure than conventional film. The pores of the membrane resemble microscopic funnels. Thanks to this property, it does not allow steam to pass through from the outside, but perfectly removes moisture from the inside. Currently, several types of roofing membranes are produced:

1. Perforated membrane. This is a reinforced film or a combined fabric with punctured holes. Used for arranging a cold sloping roof. It cannot be used for vapor protection of insulation. In frosty weather, steam may settle on the inner surface of the membrane.
2. Porous membrane. It has many interfiber pores for the passage of water vapor between them. The vapor permeability of a material can be different; it depends on the size of the pores and the degree of hydrophilicity of their walls. It is not recommended to use this type of vapor protection in highly dusty conditions. In dry and windy weather, dust can settle through the gaps onto the membrane and close the pores.
3. Three-layer superdiffusion membranes. Made from several layers. They have no openings into which dust or moisture can penetrate, which is a significant advantage. The membranes do not lose high vapor permeability in dusty environments. It is also worth noting their excellent windproof ability.
4. Double-layer film membranes. A cheaper version of a multilayer product. The absence of one of the protective layers significantly impairs reliability.

Vapor barrier materials must be elastic, durable and easy to use. When fastening with dowels, self-tapping screws, staples, nails, it is necessary that they do not tear, but at the same time fit tightly to the fastening.

Helpful advice! When choosing a vapor barrier material, special attention must be paid to quality, since this is the bottom layer of the roof structure and its repair is almost impossible.

Basics of making the right choice

When arranging a roof, it is important not only to know how to properly install a vapor barrier, but also how to decide on the right material. When choosing, it is necessary to take into account, first of all, the type of roofing material.

If the roof decking is planned to be made from materials with low thermal conductivity: slate, tiles, ondulin, onduvilla, diffusion vapor barrier membranes should be used.

Roofs made of metal tiles, corrugated sheets and seam roofing (joining sheets using a seam) are recommended to be protected using a vapor-proof film with an anti-condensation layer.

When choosing vapor barrier materials, the following parameters must be taken into account:

• vapor permeability;
• durability of operation;
• installation features;
• price.

The level of vapor permeability is measured in g/m² per day. The lower the permeability, the more reliably the insulation, finishing, and structural elements of the roof are protected from getting wet. To a certain extent, the film must provide air exchange, otherwise a greenhouse effect will be created for the room. Anti-condensation polypropylene films and breathable diffusion membranes provide optimal vapor protection.

The durability of vapor barrier materials is due to a number of qualities:

• tensile and tear strength;
• resistance to high temperatures;

• immunity to ultraviolet radiation.

Budget polyethylene film can tear during installation and be destroyed by temperature changes. Vapor barrier membranes made of non-woven artificial fibers with a protective layer are distinguished by their durability. They are resistant to mechanical damage and temperature.

Installation features must be known before purchasing film, since the quantity can be calculated correctly only if you know the amount of overlap. Also, the purchase of related materials directly depends on the installation method. If the adhesion of the vapor barrier material to the mounting tape is low, this will inevitably subsequently lead to a violation of the tightness of the vapor barrier layer. Therefore, it is necessary to purchase a different type of adhesive tape.

The price of a vapor barrier for a roof directly depends on its quality. Budget options don't last long. It is necessary to be able to correctly calculate the cost of the material. A low price per roll may not mean optimal cost, but may be a consequence of small footage. Only comparing the price per 1 m² of different types of vapor barrier will help you make the right choice.

Helpful advice! The quality of the film must match the quality of the roofing material. If the material is designed for long-term use, and the validity period of the vapor barrier is shorter, when replacing it you will have to dismantle the entire “roofing pie”.

Sequence of laying vapor barrier: basic rules

There are two types of vapor barrier: roll and sheet.

Installation of roll laying is carried out as follows:

• the material is rolled out;
• measure the required length of the canvases and place them with an overlay (100–200 mm) on adjacent fragments;
• fixed with staples or wooden slats;
• joints and overlaps are secured with vapor barrier tape (or other adhesive tape).

Sheet installation requires the preliminary creation of a wooden sheathing or profile frame into which the waterproofing will be laid. You can secure it with self-tapping screws or a stapler (according to the material).

When laying a “roofing cake” the question is: “Which side should I lay the vapor barrier on?” – appears among the first. A film that is identical on both sides does not cause any difficulties during installation: whichever side you place the vapor barrier on, the effect will be the same. The film, which has a two-layer structure, where one side is smooth and the other is rough (to retain condensation), is placed with the smooth side outward (adjacent to the insulation), and the rough side inside the room.

Related article:

Carrying out waterproofing work on the foundation using roll materials of various types: detailed instructions.

It is also easy to determine which side to lay the foil vapor barrier against the insulation. Since this type of vapor barrier is intended not only to block moisture vapor, but also to retain heat, the reflective side (foil) should be directed inward, towards the room.

Membrane vapor barrier can be double-sided, and then for its effectiveness it does not matter which side of the vapor barrier of this type is located to the insulation. If the membrane vapor barrier is one-sided, the manufacturer must indicate the wrong side.

Basic rules for installing vapor barrier:

• cleaning and drying the coating;
• the vapor barrier film should be installed without sagging, with slight tension;
• a ventilation system is required for proper functioning;
• Sealing of joints is required.

Helpful advice! When purchasing waterproofing, you should study the instructions (annotation). Sometimes not one, but two ventilation blows are required.

How to properly install a vapor barrier for a roof

Installing a roof vapor barrier is a process whose complexity depends on the type of roof.

The more intricate the rafter structure and, accordingly, the shape of the roof, the more expensive and difficult the task of high-quality insulation becomes. Installation of water vapor barrier for the roof should be carried out from the inside.

Laying of canvases can be done vertically and horizontally. If the horizontal method is chosen, then you need to start mounting from the top. Each subsequent canvas is laid on the previous one with an overlap of at least 10 cm. The seams are sealed with tape. You can use single-sided tape, it is applied on top. Double-sided tape is placed inside.

If the installation of vapor barrier for the roof is carried out along the rafter legs, i.e. vertically, then the overlap of the sheets should be done on wooden rafters. The vapor barrier material is attached to the wooden structural elements with staples or galvanized nails. It is advisable to reinforce the places where the joints are glued with pressure strips, which are especially important to use on roofs with a slope of up to 30 degrees and with low insulation density.

Helpful advice! Used wooden planks and bars must be treated with an antiseptic. This will significantly extend their full service life.

If the structure has skylights, hatches or other passages through the roof, then along their perimeter you need to stick a butyl rubber self-adhesive tape, which will prevent the passage of moisture and steam and firmly seal the cutouts in the vapor barrier film, even if they are adjacent to a not entirely flat surface. This type of tape has high water-repellent properties and good resistance to temperature influences. In addition, it easily levels out unevenness.

If ventilation pipes pass through the roof, the film must be wrapped and tightly wrapped around them, securely secured with one-sided adhesive tape.

Mistakes made during the installation of vapor barrier

In the absence of experience and professional advice, a number of mistakes are made when laying vapor barriers, which will subsequently significantly affect the efficiency of the vapor barrier. The most common of them:

• loose connection of the film to purlins, crossbars, valley, spine and ridge beams;

• not knowing which side to lay the vapor barrier against the insulation;
• use for sealing narrow adhesive tapes (up to 50 mm);
• when sealing openings, no deformation reserve of the film is left (20–30 mm);
• the polyethylene product around the roof windows is not closed from the inside, as a result of which after some time it is destroyed by ultraviolet radiation and low temperatures;
• the film goes around the rafter legs. Moisture will penetrate into the gap between the rafters and the vapor barrier;
• In places where the film adjoins significantly uneven surfaces, no special glue is used. Construction tape, butyl and other types of adhesive tapes do not provide complete tightness in such cases.

Helpful advice! When laying a vapor barrier, you should not neglect even a seemingly insignificant rule or violate the installation sequence. A good result will be achieved only if all requirements are met.

Vapor barrier for ceilings in wooden floors

Wood is an organic material and therefore allows vapor to pass through. But excessive moisture with steam is also undesirable for it, since under its influence the tree expands and can rot. In order for the ceiling, which is located under a cold attic, to remain in normal condition, it is necessary to install the correct vapor barrier. It is important to follow the installation sequence here. The component that has minimal vapor barrier is placed first. It should be zero or close to zero. The following layers have a permeability higher than the previous one.

From the room, the vapor barrier should look like this:

• vapor barrier. Polyethylene or polypropylene film, diffusion membrane. Placed on top of the ceiling;
• thermal insulation. Roll, backfill or tile material. Fills the void between floor beams;
• waterproofing. A layer of diffusion membrane or perforated polyethylene. Installed only when using an attic.

If you do not plan to use the attic space, then the waterproofing layer is transferred under the slopes, where it protects the entire roof.

Laying vapor barrier material on wooden floors is done around each beam. The strips are mounted perpendicular to the beams. In this case, the material is not stretched; slight sagging is mandatory.

With a panel wooden floor, each compartment is wrapped. The material is cut out according to the size of the shield and the height of the walls.

Helpful advice! You should not rewind the rolled vapor barrier material, so as not to confuse the side that should be in contact with the ceiling (it is indicated by the manufacturer).

Vapor barrier for a bath

A bathhouse is a room that requires high temperature and is characterized by a high level of humidity. The vapor barrier of this building is used to preserve the insulation, as well as to protect wooden structures from moisture. When choosing vapor barrier materials, it is necessary to take into account that it is advisable to use different insulation for different premises:

• for a steam room, the best option is a foil vapor barrier that reflects heat and creates an additional thermos effect;
• the shower room can be vapor-insulated with polyethylene or polypropylene film;

• in the dressing room and rest room, a membrane vapor barrier will be appropriate, which will ensure the necessary air exchange.

One of the recognized modern vapor barrier materials is Izospan V. It has a fairly wide purpose. The instructions for use of the Izospan V vapor barrier indicate that it can be used for:

• roofing structures;
• gender;
• walls, both outside and inside;
• laminated floors and parquet.

The double-sided structure of this material allows it to be actively used for vapor barrier in bathhouses. How to lay a vapor barrier and which side to attach the Izospan B vapor barrier is suggested by the presence of a different structure of the sides: the rough surface is designed to absorb steam, therefore, it should be directed inside the room.

Is a vapor barrier necessary when insulating with mineral wool?

Mineral wool insulation is an effective type of thermal insulation that is actively used in modern construction. But it has one rather significant drawback: when it gets wet, mineral wool is destroyed and loses its heat-insulating properties. That is why the use of vapor barrier film, along with this insulation, is extremely necessary. It will create a barrier that will protect the thermal insulation layer from the effects of steam and make it possible to keep the rooms warm.

Which side should the vapor barrier be placed if mineral wool insulation is used?

If a double-sided film with a moisture-absorbing layer is used, it should be directed towards the room from which steam flows rise. The smooth side is adjacent to the insulation. When using a material with a foil-coated surface, the aluminum coating will become a barrier to the penetration of moisture into the heat-insulating material. Therefore, it is this surface that should be directed towards the room.

Helpful advice! If mineral wool is used to insulate rooms with high levels of humidity, then it is more reliable to use a vapor barrier with a foil-coated layer, since it has the lowest level of vapor permeability.

Prices and manufacturers

TechnoNIKOL company is a leading manufacturer of vapor barrier materials in Russia and the CIS. The products are manufactured on a polymer basis. There are the following types of TechnoNIKOL vapor barriers:

• for pitched roofs (has the ability to partially allow steam to pass through);
• for flat roofs (has high strength and elasticity);
• reinforced (reinforced three-layer film of high strength);
• universal (used for all types of roofs).

The average price of TechnoNIKOL vapor barrier per m² is 20 rubles. This is a low price level with good quality.

Vapor barrier Yutafol – products from a European manufacturer, which are distinguished by their variety, satisfying various purposes when installing vapor barriers. For the convenience of the buyer, in order to easily distinguish between the materials and not to confuse waterproofing, windproofing and vapor barrier, they have the names Yutakon, Yutavek and Yutafol (respectively). In addition to standard types of products, this Czech company produces Yutafol N110 Special film with a self-extinguishing reagent that reduces the level of flammability to a minimum. The price of this film per 1 m² is from 17 rubles. Reducing the cost of products due to simple packaging is a successful decision by the company.

Vapor barrier Axton – products of the French company Leroy Merlin. It has three types: B, C and D. Axton B - polyethylene film, a budget option. It will last a considerable time if you avoid mechanical damage and fix it correctly, using not a stapler, but special nails with wide heads. This material is used for indoor installation only.

Axton C is a polypropylene product, more durable and versatile. Has different permeability indicators. This is a two-layer material, it is recommended for insulated and non-insulated types of roofs with a variety of designs. Axton D looks like an awning. Used for water and vapor barrier. Characterized by high strength and ease of installation. The products of this company are distinguished by a high level of environmental friendliness.

Vapor barrier materials Tyvek are produced at the plant in Luxembourg. The base is high quality polyethylene, non-woven structure. The main difference between the products is environmental friendliness and “breathable” membranes with controlled vapor permeability created using innovative technologies. The price of Tyvek vapor barrier is 7–10 percent higher than the cost of domestic analogues.

The price of a vapor barrier for a ceiling most depends on the quality of the material, its density and manufacturer. That is why branded products from foreign companies are more expensive.

Roof vapor barrier:modern solution for moisture protection

The roof is a structural element that can withstand constant double load. From the outside, it is exposed to atmospheric phenomena: precipitation, sunlight, low temperatures, wind. On the inside, it experiences internal effects of temperature and humidity. In such conditions, it is simply impossible to overestimate the need for proper vapor barrier installation, the absence of which can lead to the destruction of the roof and subsequently the building itself.

Modern technologies have made it possible to create films from polymers that can provide vapor barrier of the required level. A wide selection of material allows it to be used in accordance with the conditions and intended purpose. By carefully studying how to properly install a vapor barrier, fulfilling all technical requirements, you can create a healthy microclimate in the premises and ensure the building as a whole will last for many years without major repairs, while maintaining an aesthetic appearance.

There is no reason to consider the price of vapor barrier for roofing per m² to be high, which makes the material affordable for any developer.

Making an informed and rational choice of materials and correctly installing a vapor barrier is the desire of every homeowner. The content of the article is intended to help you install the vapor barrier yourself. But even if such a solution is unacceptable, you need to be aware in order to correctly assess your costs and the quality of work of the hired specialists.

Modern roofing materials are an almost absolute guarantee that moisture will not penetrate into the roof, regardless of external conditions. However, from inside the premises, the roofing pie is not protected from this in any way. First of all, the thermal insulation material, which loses its performance characteristics when wet, is at risk. As a result, the house becomes cold and damp. A properly installed vapor barrier will help prevent this process.

The need for vapor barrier

The warm air in the room is saturated with vapor and rises, trying to escape through any openings. But since the air temperature and humidity in the under-roof space are much lower, condensation forms, which can be localized on the insulation, which can lead to its destruction.

Vapor barrier material protects insulation from the destructive effects of moisture

A more severe situation is observed in the cold season. The steam escaping into the under-roof space stops, but first turns into frost, after which it forms an ice crust that will freeze absolutely any insulation in a short period of time.

To preserve the insulation, a vapor barrier is needed

With the onset of spring, the ice in all pores begins to melt and erode the interior finish. This becomes the reason that the insulation ceases to perform its functions, and mineral wool will become unusable after just a year of such use, while polystyrene foam will last a little longer.

Without a vapor barrier, the insulation will last much less

That is why a vapor barrier layer is required. Its main task is to prevent condensation from reaching the insulation. This will warn:

• the appearance of mold;
• heat leakage from the premises of a private house;
• rotting of all wooden structures.

Materials used

There is a wide variety of modern building materials that have vapor barrier properties. Conventionally, they are divided into three groups:

1. Polyethylene film. This type of material is universal because it can perform several functions at once. The film is covered with a special reinforced fabric. There are two types of this vapor barrier material: with and without perforation. But the holes are so small that they cannot be seen with the naked eye. For installation, it is necessary to use seals and connecting tapes, since the film is produced in rolls. The strips must be attached as tightly as possible, otherwise the functionality of the layer will be impaired. There are also polyethylene films with a foil layer that retains heat indoors.

   Vapor barrier polyethylene film reinforced with fabric

2. Polypropylene film. Used as a hydro- and vapor barrier material. On one side, the film is covered with an anti-condensation layer consisting of viscose-cellulose fiber. The principle of operation of this material is quite simple: condensate protruding from the side of the film that faces the insulation is absorbed into it and therefore does not fall on the insulation. Since the installation of the roof implies the presence of a ventilation gap, the moisture absorbed into the vapor barrier dries out.

   Polypropylene film has a smooth and rough side

3. "Breathing" film. The most modern vapor barrier material. Combines vapor and water resistance properties. The main advantage is that there is no need to create a ventilation gap, and this allows you to significantly save under-roof space. This membrane allows moisture to pass through itself, which subsequently settles on the rough layer of material, after which it is absorbed into it and dries. This allows the insulation to remain dry. There are different types of vapor barrier membranes available, which can be single- or double-sided.

   Single-sided membranes conduct steam in only one direction; double-sided membranes can be laid on either side

For vapor barrier, it is better to use a non-perforated film, since perforated film is more suitable for waterproofing.

A very important stage in arranging a roof vapor barrier can be considered not only the process of its installation, but also the choice. The quality of the roofing as a whole, as well as its service life, depends on this. When choosing, remember that the more weight the material has, the stronger it is. Typically it ranges from 60 to 270 g/m2. As for the vapor permeability parameter, you need to choose a material with a minimum value. The recommended parameter is less than 1 g/m2 per day.

How to properly install roof vapor barrier

Before installation, it is recommended to once again make sure that you have purchased exactly the vapor barrier material. You should also make sure that the vapor barrier you purchase is compatible with your roofing material. In this case, “Izospan B” is universal, which can be used regardless of the type of roofing pie.

Which side to put the vapor barrier on the roof

There are certain rules for laying vapor barrier material. Regardless of the type, the film has two surfaces: one smooth, the other rough. You need to lay it with the smooth side on top of the insulation. At the same time, carefully ensure that the material fits as tightly as possible; gaps are not allowed.

The smooth surface of the vapor barrier must be in contact with the insulation

When laying a vapor barrier membrane, it is necessary to provide a ventilation gap between the vapor barrier and the decorative roof sheathing. It should be at least 5 cm, and the type of roofing material in this case does not matter. A counter-lattice, which is mounted directly on the membrane, can provide this ventilation gap.

How to attach a vapor barrier to rafters

The material must be attached to the rafters from the inside of the insulation. For fastening, you can use different parts, for example, a construction stapler or galvanized nails. Try to minimize the number of punctures in the material, as this may cause condensation to penetrate through these holes during the operation of the roof.

You can use a stapler or nails to attach the vapor barrier.

The option of attaching a vapor barrier material to the rough lining of the attic is also allowed.

The material can be laid in horizontal or vertical strips, rolling out the entire coating without breaks. Additionally, it is necessary to process the joints, both vertical and horizontal. To do this, you need to lay the vapor barrier overlapping, the size of the overlap should be at least 15 cm. Next, seal the joints with a special tape, but you can only choose one that is designed to work with vapor barrier film.

All joints must be sealed with wide tape

It is also necessary to seal the joints of the material with a wooden or concrete base, even if a stapler or nails were used for fastening.

The vapor barrier film must be laid without sagging; it must be well stretched.

Video: rules for installing vapor barrier

Installation errors

Despite the fact that the process of installing a vapor barrier film is quite simple, sometimes mistakes cannot be avoided, but they are typical and can be prevented:

• loose connection of the film to the purlins, valley and ridge beams, especially for complex roof structures;
• the use of a narrow connecting tape, because of this, the sealing of the seam may be broken during the operation of the roof;
• lack of deformation reserve when installing a roof with windows;
• lack of internal protection of a vapor barrier film around the roof windows, due to which ultraviolet rays gain open access to this material and destroy it;
• the film bends around the rafter legs, which creates a gap through which moisture can pass and be absorbed into the insulation.

Video: consequences of improper vapor barrier

Steam is a substance that is quite difficult to block, so vapor barrier of the roof of a private house is a responsible mission. The safety of the roofing pie and wooden structures and the long service life of the roof can only be guaranteed by proper installation of vapor-proof material.

Modern roofing materials are an almost absolute guarantee that moisture will not penetrate into the roof, regardless of external conditions. However, from inside the premises, the roofing pie is not protected from this in any way. First of all, the thermal insulation material, which loses its performance characteristics when wet, is at risk. As a result, the house becomes cold and damp. A properly installed vapor barrier will help prevent this process.

The need for vapor barrier

The warm air in the room is saturated with vapor and rises, trying to escape through any openings. But since the air temperature and humidity in the under-roof space are much lower, condensation forms, which can be localized on the insulation, which can lead to its destruction.

Vapor barrier material protects insulation from the destructive effects of moisture

A more severe situation is observed in the cold season. The steam escaping into the under-roof space stops, but first turns into frost, after which it forms an ice crust that will freeze absolutely any insulation in a short period of time.

To preserve the insulation, a vapor barrier is needed

With the onset of spring, the ice in all pores begins to melt and erode the interior finish. This becomes the reason that the insulation ceases to perform its functions, and mineral wool will become unusable after just a year of such use, while polystyrene foam will last a little longer.

Without a vapor barrier, the insulation will last much less

That is why a vapor barrier layer is required. Its main task is to prevent condensation from reaching the insulation. This will warn:

• the appearance of mold;
• heat leakage from the premises of a private house;
• rotting of all wooden structures.

Materials used

There is a wide variety of modern building materials that have vapor barrier properties. Conventionally, they are divided into three groups:

1. Polyethylene film. This type of material is universal because it can perform several functions at once. The film is covered with a special reinforced fabric. There are two types of this vapor barrier material: with and without perforation. But the holes are so small that they cannot be seen with the naked eye. For installation, it is necessary to use seals and connecting tapes, since the film is produced in rolls. The strips must be attached as tightly as possible, otherwise the functionality of the layer will be impaired. There are also polyethylene films with a foil layer that retains heat indoors.

   Vapor barrier polyethylene film reinforced with fabric

2. Polypropylene film. Used as a hydro- and vapor barrier material. On one side, the film is covered with an anti-condensation layer consisting of viscose-cellulose fiber. The principle of operation of this material is quite simple: condensate protruding from the side of the film that faces the insulation is absorbed into it and therefore does not fall on the insulation. Since the installation of the roof implies the presence of a ventilation gap, the moisture absorbed into the vapor barrier dries out.

   Polypropylene film has a smooth and rough side

3. "Breathing" film. The most modern vapor barrier material. Combines vapor and water resistance properties. The main advantage is that there is no need to create a ventilation gap, and this allows you to significantly save under-roof space. This membrane allows moisture to pass through itself, which subsequently settles on the rough layer of material, after which it is absorbed into it and dries. This allows the insulation to remain dry. There are different types of vapor barrier membranes available, which can be single- or double-sided.

   Single-sided membranes conduct steam in only one direction; double-sided membranes can be laid on either side

For vapor barrier, it is better to use a non-perforated film, since perforated film is more suitable for waterproofing.

A very important stage in arranging a roof vapor barrier can be considered not only the process of its installation, but also the choice. The quality of the roofing as a whole, as well as its service life, depends on this. When choosing, remember that the more weight the material has, the stronger it is. Typically it ranges from 60 to 270 g/m2. As for the vapor permeability parameter, you need to choose a material with a minimum value. The recommended parameter is less than 1 g/m2 per day.

How to properly install roof vapor barrier

Before installation, it is recommended to once again make sure that you have purchased exactly the vapor barrier material. You should also make sure that the vapor barrier you purchase is compatible with your roofing material. In this case, “Izospan B” is universal, which can be used regardless of the type of roofing pie.

Which side to put the vapor barrier on the roof

There are certain rules for laying vapor barrier material. Regardless of the type, the film has two surfaces: one smooth, the other rough. You need to lay it with the smooth side on top of the insulation. At the same time, carefully ensure that the material fits as tightly as possible; gaps are not allowed.

The smooth surface of the vapor barrier must be in contact with the insulation

When laying a vapor barrier membrane, it is necessary to provide a ventilation gap between the vapor barrier and the decorative roof sheathing. It should be at least 5 cm, and the type of roofing material in this case does not matter. A counter-lattice, which is mounted directly on the membrane, can provide this ventilation gap.

How to attach a vapor barrier to rafters

The material must be attached to the rafters from the inside of the insulation. For fastening, you can use different parts, for example, a construction stapler or galvanized nails. Try to minimize the number of punctures in the material, as this may cause condensation to penetrate through these holes during the operation of the roof.

You can use a stapler or nails to attach the vapor barrier.

The option of attaching a vapor barrier material to the rough lining of the attic is also allowed.

The material can be laid in horizontal or vertical strips, rolling out the entire coating without breaks. Additionally, it is necessary to process the joints, both vertical and horizontal. To do this, you need to lay the vapor barrier overlapping, the size of the overlap should be at least 15 cm. Next, seal the joints with a special tape, but you can only choose one that is designed to work with vapor barrier film.

All joints must be sealed with wide tape

It is also necessary to seal the joints of the material with a wooden or concrete base, even if a stapler or nails were used for fastening.

The vapor barrier film must be laid without sagging; it must be well stretched.

Video: rules for installing vapor barrier

Installation errors

Despite the fact that the process of installing a vapor barrier film is quite simple, sometimes mistakes cannot be avoided, but they are typical and can be prevented:

• loose connection of the film to the purlins, valley and ridge beams, especially for complex roof structures;
• the use of a narrow connecting tape, because of this, the sealing of the seam may be broken during the operation of the roof;
• lack of deformation reserve when installing a roof with windows;
• lack of internal protection of a vapor barrier film around the roof windows, due to which ultraviolet rays gain open access to this material and destroy it;
• the film bends around the rafter legs, which creates a gap through which moisture can pass and be absorbed into the insulation.

Video: consequences of improper vapor barrier

Steam is a substance that is quite difficult to block, so vapor barrier of the roof of a private house is a responsible mission. The safety of the roofing pie and wooden structures and the long service life of the roof can only be guaranteed by proper installation of vapor-proof material.

Almost every owner of a private house or country house knows that the main “enemy” of the roof is the steam emitted by a person when breathing, formed during cooking, which is converted into condensation and settles in the roofing carpet. This can lead to deterioration in the functioning of the thermal insulation layer and, ultimately, to the destruction of the roofing.

To avoid such situations, it is necessary to use a vapor barrier when laying the roofing. For this purpose, special building materials with a vapor permeability coefficient are used, which will reduce the risk of damage to the insulation.

Laying a vapor barrier has its own characteristics and subtleties, which you need to know about if you are going to carry out the installation yourself.

It is important to note: If there are stove or fireplace pipes on the roof, then a double layer of vapor barrier is required next to them, since one can be damaged by the heat emanating from them.

Leave a gap between the vapor barrier material and the insulation for additional heat retention. The choice of film is best made taking into account the climatic conditions of your region, the area where the house is built and the type of roofing used.

Note to owners of houses made of timber: When building a house made of timber, you can refuse vapor barrier, since this natural material has the ability to absorb moisture, thereby preventing the formation of condensation.

Instructions for laying roof vapor barrier

Before installing a vapor barrier, install insulation and waterproofing; carefully stretch the vapor barrier film, otherwise it will not function in a sagging state; the film can be mounted using adhesive tape or double-sided tape on a metal, brick or concrete surface. When installing in a wooden house, you can use nails with a wide head, hammer them in at intervals of 30 centimeters; fasten the film overlapping in several layers, leaving gaps for ventilation of 5 cm.

It is important to note: In order to maintain the integrity of the vapor barrier of the entire house, it is necessary to ensure that the film is covered with a continuous carpet without tears, scratches or holes.

In general, the arrangement of the roofing carpet should look like this:

installation of a vapor barrier film on the interior side; installation of insulation; installation of a windproof membrane; roof sheathing; installation of roofing.

Using a vapor barrier also helps prevent the formation of mold and mildew. By using this layer, you, first of all, take care of the health of your loved ones.

The roof structure is a complex system. It consists of several layers of dissimilar materials, each of which performs its own unique function.

To ensure comprehensive protection of the building from environmental influences, it is necessary to carry out all installation work with high quality, as well as the correct choice of basic and insulating materials. This whole process is briefly called roof insulation.

The standard composition of the roofing cake includes:

Why do you need a roof vapor barrier?

Why do you need a roof vapor barrier?

The vapor barrier layer protects the roof from the penetration of water vapor into the thermal insulation. The fact is that most insulating materials have a porous structure, since the air they contain acts as a heat insulator. When it comes into contact with a colder environment, the steam turns into condensate, which is retained in the voids.

This can lead to disruption of the functionality of the heat-insulating material, as well as the occurrence of decomposition and rotting processes in the summer. In winter, freezing water expands, thereby destroying the bonds between the cellular elements.

The release form of vapor barrier films is a roll.

Vapor barrier can be made from various materials. Some of them have additional positive properties that increase the efficiency of operation of the building’s interior. Installing a vapor barrier on a roof is not as difficult as it seems at first glance, but it requires a careful approach and accuracy.

Types of vapor barrier

Single layer polyethylene films

Made from low-density polyethylene, which provides an increased degree of steam penetration. This material often has defects due to the ingress of foreign particles during manufacturing. The cheapest type of insulating material.

Polyethylene films with reinforcement

Compared to single-layer polyethylene, reinforced vapor barrier is slightly thicker, since it includes a reinforcing frame. It consists of polymer twisted threads located in mutually perpendicular directions. The mesh is attached to the polyethylene base by warm pressing.

This technique does not affect the waterproofing and mechanical properties of the material, but can reduce the degree of vapor barrier.

Anti-condensation film

It is made of two layers: smooth and fleecy. The smooth layer is attached to the insulated surface.

The fleecy layer is created from cellulose fibers. When steam hits such a surface, it clings to the fibrous structure, thereby preventing moisture from flowing onto the underlying structures of pitched roofs. Excess water is removed along with the air through the ventilated space.

Polymers with foil layer

They are made of penofol or foamed polypropylene, coated with a thin layer of metal. Due to the reflective properties of metal surfaces, such vapor barrier provides an additional function of protection against heat loss.

Membranes (film for roof vapor barrier)

Membrane vapor barrier materials are divided into five main classes:

Has increased resistance to moisture and wind. It is laid between the roofing covering and the heat-insulating layer. Manufacturing technology: spunbond.

This vapor barrier does not allow moisture to flow through the cracks of the roofing material, as well as from the condensation that forms. The absence of a laminating layer allows the use of such membranes in roofing structures with a slope of more than 35 degrees. To remove excess moisture, it is necessary to install ventilation holes from a double sheathing located between the membrane and the insulation. Type AM.

Unlike Type A, it has a multilayer structure. It is placed between the insulation and the roof to provide adequate protection from negative atmospheric influences. The most common is a three-layer construction, consisting of two layers of spunbond with a diffuse film located between them.

It acts as a waterproofing agent, as it allows steam to pass through but retains water. Laying is done directly on the heat-insulating layer, which reduces labor costs for creating a ventilation gap. Type B. Two-layer material.

Consists of a layer of vapor barrier film and spunbond. It is used to protect insulation from internal building vapors. Used only in insulated roof structures. Type C.

It is manufactured similarly to type B membranes. It has a stronger and thicker layer of spunbond, which provides better protection of the insulation from moisture. Used in insulated and non-insulated, pitched and flat roofs. Type D.

Consists of polypropylene fabric, protected on one side with a laminating polymer coating. The structure of the material allows it to withstand significant mechanical stress. This dictates its installation between the insulation and the attic floor screed, as well as in non-insulated roofing structures.

Which side is the vapor barrier for the roof laid on?

The principle of installation of vapor barrier materials depends on which side the layer responsible for repelling water vapor is located:

ordinary and reinforced polyethylene films, as well as membranes of type A and AM can be laid on the insulation on either side. Anti-condensation vapor barriers are laid with the smooth side towards the insulation, and the fleecy side towards the vapor formation. Foil elements are laid with a metal layer inside the room, since this is where the light coming out of the building should be reflected heat. Type B membranes are laid with the film side to the thermal insulation layer. Type C and D membranes must be adjacent to the insulation with their rough side.

We have figured out which side to lay the vapor barrier on the roof, now we will look in detail at how to properly lay the vapor barrier on the roof.

Vapor barrier for the roof: how to install it correctly using special technology

Laying a vapor barrier on the roof is carried out as follows:

Laying can be done vertically and horizontally. In the second option, the installation of roof vapor barrier is carried out starting from the ridge part of the roof. Each subsequent strip is superimposed on the previous layer with an overlap, the value of which should not be more than 10 cm.

The vapor barrier is attached to wooden rafter elements using galvanized nails or a construction stapler. When installing films and membranes near attic hatches, you need to use a special vapor barrier apron, which is included in the standard package. At the junction with ventilation pipes, film and membrane structures are folded down and wrapped around pipes and are tightly fixed with construction tape. After laying the vapor barrier layer, it is necessary to nail wooden blocks.

The rules for laying vapor barrier on the roof dictate the following rule - the pitch between the sheathing bars should be 500 mm. In this case, a ventilation gap is formed, and additional fastening of the vapor barrier layer is carried out. Now you know how to lay a vapor barrier on a roof, you can move on to the issue of waterproofing. If the vapor barrier for the roof has been damaged, then small cuts or holes can be sealed with special tape for vapor barrier membranes.

Roofing pie diagram

Sealing joints with tape

Final vapor barrier option

Hydro and vapor barrier of the roof - what is the difference?

Waterproofing materials also serve the function of protecting structural elements from moisture. However, unlike vapor barriers, they are not resistant to moisture-saturated air masses.

That is, steam coming out of the premises will freely penetrate through the insulating layer. Therefore, when purchasing vapor barrier films and membranes, make sure that they are intended for the correct purpose. Read more about roof waterproofing here.

Useful video

And now we invite you to familiarize yourself with the video instructions on roof vapor barrier:

Conclusion

Vapor barrier is the lightest and thinnest layer of the roof. But neglecting its structure can negate all material and physical efforts to create a high-quality roof. Therefore, you should not neglect this important element; it will significantly increase the service life of the entire building.

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Modern film vapor barrier is designed to increase the effective service life of heat-insulating materials, wooden and metal structures. Indeed, during the operation of a residential building, residents use many sources of intense evaporation - hot baths or showers, aquariums.

If the roof is equipped with a hydrobarrier, water vapor will condense on it from the inside, constantly moistening the insulation and building structures. Wooden elements are exposed to mold fungi, and metal elements are subject to intense corrosion processes.

Application area

Today, modern SNiP standards regulate the use of vapor barriers in the following cases:

When installing a heat-insulating layer of roofing coverings in warm attics and attics.

In the case of insulation of walls of buildings from the inside. This is especially true for metal structures - garages, cabins, insulated containers and others. This measure will significantly increase the service life of mineral wool or expanded polystyrene used as insulation.

For vapor barrier of wooden floors of the first floor.

Often, in our conditions, the floors of the first floor are also equipped with an insulating layer to prevent heat from escaping from the room in winter. And if there is a significant difference in internal and external temperatures, drops of condensed moisture will naturally appear on cold floor surfaces. The result is, again, saturation of the insulation with water, which leads to a significant deterioration of its thermal insulation qualities and premature destruction of wooden floor structures.

Technology for proper installation of vapor barrier with your own hands

When laying a vapor barrier with your own hands, you should follow simple rules:

The film must be mounted with the smooth side to the vapor barrier surface - insulation of the roof, walls or floor. If a foil modification of the film is used, it should be laid with the polyethylene side facing the surface to be insulated, and with the reflective screen facing the inside of the room. It will be especially effective when equipping internal hot rooms - baths and saunas.

They are laid exclusively overlapping with an overlap of at least one hundred millimeters. Preliminary fastening to wooden structures is carried out using a construction stapler with staples, a hammer with galvanized nails or a screwdriver with anodized screws.

A prerequisite is the tightness of its execution. In practice, this means the need for careful gluing of all canvases in areas of overlap and around the perimeter. For these purposes, it is recommended to use high-quality double-sided tape, and its width should not be less than 100 millimeters.

Features of laying vapor barrier film on various structural elements of buildings

Direct installation of the vapor barrier is carried out as follows:

In the case of a vapor barrier for the floor covering, the film is spread and fixed on the surface of the subfloor. After gluing all the overlaps and the perimeter, you can lay the finished floor and floor covering.

For walls and pitched roofs, it is possible to lay a vapor barrier film with the panels arranged vertically or horizontally.

When arranging a vapor barrier for a flat insulated roof, after laying it, it is necessary to fill a frame of wooden slats 10-20 millimeters thick on top of the film. These slats serve as additional fasteners for the film material and provide ventilation between the vapor barrier and the finishing of the flat roof.

Using double-sided tape

Double Sided Adhesive Tyvek Tape for Sealing Vapor Barrier

When organizing a vapor barrier layer, the following types of double-sided tape are used:

paper based; polypropylene based.

The second option is of better quality in terms of durability and ability to withstand external destructive factors - moisture and high temperatures.

The use of double-sided polypropylene tape is especially justified when installing vapor barriers in extremely hot and humid rooms, for example, in Russian baths.

Double-sided tape is used as follows:

First, the material is unwound and glued to the edge of the lower joining sheet with the release paper facing up.

Then the next sheet of vapor barrier tape is laid out and secured with the required amount of overlap.

After this, the layer of anti-adhesive paper is removed from the upper side of the tape and, with light pressing and smoothing, both layers of the vapor barrier film are securely fastened together.

If you follow all the technological nuances of installing vapor barrier materials, using only high-quality products, you can significantly extend the effective life of the structural elements of the building - floors, walls, ceilings, roofing and the building as a whole.

Remember that your costs for installing a high-quality vapor barrier layer in a residential building will be disproportionately less than the costs of repair work due to the premature loss of insulation, load-bearing wooden structures and interior finishing materials. Therefore, insignificant savings on vapor barrier during construction of a building can result in significant losses in the future.

For more information about the technology of laying and fastening vapor barriers for a warm roof with your own hands, watch the video.

Currently, vapor barrier is one of the components of any construction. First of all, we are talking about roof vapor barrier.

The fact is that there is moisture in any room. The water itself isn't that scary. The most destructive effect on roofing materials is caused by condensation that forms on the inner surface of the roof in hot weather.

Scheme of vapor barrier of walls from the inside.

Laying a vapor barrier on the roof means protecting all building and finishing materials from the harmful effects of moisture. This is especially true for private houses and cottages, where in most cases mineral wool is used as insulation.

Condensation can penetrate its structure, destroying it and significantly reducing its service life. Below you will find instructions on how to install a roof vapor barrier. This is where it is worth fighting condensation.

Materials used for roof vapor barrier

Currently, a huge variety of materials are used that are used for vapor barrier. When it comes to roofing, the choice is simply huge. Until recently, roofing felt was the main material used for roofing.

Recently, people have begun to refuse it, as it has a limited service life. Under the most favorable conditions, roofing material will last no more than five years. In addition, there are now many materials with similar composition and properties.

Glassine is a material that is very often confused with roofing felt. They are similar in appearance, but the production technology is somewhat different.

In the production of glassine, cardboard is also the main substance. This material lasts much longer than roofing felt. It is perfect for roof vapor barrier.

Properties and scope of application of vapor barrier materials.

Films have also found quite wide application in roof vapor barrier. They are mainly installed in private houses, where a residential attic, that is, an attic, is equipped. There are several types of polyethylene films used for vapor barriers.

For example, reinforced materials have found wide application in this area. Don't forget about polypropylene films. They are currently becoming increasingly popular as they have a fairly long service life.

Today, breathable films are the most widely used. They are also called membranes. They differ from each other in the installation method.

Modern membranes can be single-sided or double-sided. Many experts unanimously claim that membranes can reduce the cost of air conditioning and heating a room several times. This is a fairly profitable option for roof vapor barrier.

It is membranes that are currently used most often for these purposes. Moreover, you don’t have to be a construction specialist to lay such material on your roof. It is worth noting the fact that membranes are installed in our country using a variety of technologies.

This is due to the fact that in Russia there is no strict rule according to which this should be done. Each specialist and company does the work in their own way. Basically there is nothing wrong with this.

Now it’s worth touching on the topic of vapor barrier instructions. It is worth considering the main aspects associated with the arrangement of this layer on your roof.