When constructing an insulated attic roof, a vapor barrier must be used. The absence of this layer in the roofing pie leads to wetting of the insulation and premature destruction of the rafter system.

Vapor barrier for attic roof protects insulation and load-bearing materials wooden structures roofs from saturation with moist vapors that appear as a result of human activity.

This reduces the risk of fungus and mold appearing in the under-roof space.

Do not confuse vapor barriers with superdiffusion membranes. The latter are laid on top of the insulation and play the role of waterproofing, but at the same time retain the ability to “breathe” and remove moisture from the surface of the insulation.

Materials for roof vapor barrier are represented by several types of films:

Single layer films made of polyethylene or polypropylene. They are characterized by low strength; if handled carelessly, the film can easily be torn.

Which vapor barrier to choose for the attic?

• Multilayer films— have higher strength and service life, and can be additionally reinforced with a reinforcing layer.

  Reflective films with a reflective layer of foil - allows you to retain heat in the room and will become great solution when installing a roof over a sauna, swimming pool or bathroom.

Read also: how to properly insulate the roof of a house.

1. If financial opportunities allow, choose Delta Reflex or AirGuard Reflective films.
   Delta DAWI GP is a little simpler and cheaper.
2. AirGuard Sd5 - suitable for houses with non-permanent residence.

   Has limited vapor permeability to remove residual moisture from the room.

3. Jutafol are Czech films from the Juta company.

   Lots of good reviews from builders, excellent choice in terms of price-quality ratio.

4. Ondutis and Izospan are an economical option.

Rules for installing vapor barrier film

The vapor barrier film is laid on top of the insulation from the attic side and fixed using a construction stapler.

The joints of the canvases are taped with mounting tape to ensure tightness.

When working with the material, you should consider the following tips:

The sheets can be laid in any direction if there is a rough insulation file. When installing directly on the rafters, it is better to place the sheets horizontally.

The minimum overlap of one canvas over another should be 10 cm.

Joints and junction points must be carefully taped.

When working with window openings, it is worth considering a deformation margin (fold). Near windows it is important to pay attention Special attention sealing joints and protecting the material from sunlight.

After fixing the vapor barrier, wooden sheathing is done with 25 mm slats.

It is needed for attaching the rough sheathing and creating a ventilation gap. When finishing the ceiling and walls of the attic with plasterboard, a special metal profile is used instead of bars.

Competent and high-quality performance of attic vapor barrier work will extend the life of the roof and save the home owner from costly repairs.

mvnvdanvamnbaa

Benefits of this option
What a cold roof
Installation steps
Roof structure for metals, including waterproofing
Tools and accessories for installing a cold attic

Currently, specialists use all types of roof structures when building a private house, but most often they build a cold roof.

This perfect option when the attic is not intended for use as a residential building. Below we will talk about how to properly install a cold metal roof.

Which steam bar to choose for the attic?

Benefits of this option

The design of such a roof is quite simple - you need to build a building, apply a layer of waterproofing, a box and control panel, and a roof. The main thing when installing a cold roof is to provide air clearance to allow condensed moisture to be removed. This is necessary to ensure that the supporting structure and roofing material are not exposed to moisture.

In itself, the installation of such a roof should not be accompanied by complications during the work; it is only necessary to properly fix the roofing coverings so as not to leave precipitation through the connection in the underground space. Before you create a mug on the roof of a cool attic, you need to complete a full list of calculations, determine the slope of the skateboard, rotate the basket and choose the appropriate method of fastening the sheet metal.

What a cold roof

Technology cold roof metal roofing takes care of the initial installation of the roofing system, after which the membrane will be placed on it and polyethylene film which will provide waterproofing.

They fill the control box, assemble it and lay down the metal roofing.

The characteristic of this type of roof is that there is no need to install insulation - all that is necessary is to provide vents under the ridge and on the slopes to remove moisture. Make sure everything preliminary calculations precisely defined.

The roof installation has the following characteristics:

1. If you plan to build a hot roof over time, the protection of the moisture barrier membrane must be careful.

   If you plan to build an attic, a PVC membrane must be present.

2. If the roof does not need to be insulated in the future, it will be necessary to install micro-perforated flashing, which is used for cold roofs. It is impossible to install insulation with such a film, and if you continue to insulate you will need to buy a new membrane.

   Otherwise, the roof will not be protected from moisture in the future, the heaters will not have enough time to dry, and the roofing material will turn brown over time.

Installation steps

When installing the membrane to protect against moisture, it should be noted that it must remain a small roller of at least 20 mm. In this way, condensation moisture can be achieved, thereby protecting the rafters and other roof elements from decay.

To ensure that the water does not evaporate in time, without stagnating and thereby creating an unfavorable environment, care should be taken to include a fan steam in the design, which is installed between the repellents to protect the film and the ridge roof.

Such a clearance will allow simple circulation of air flow in the room under the roof and removal of all condensation. The built-in membrane must not be damaged or otherwise damaged. The best way to fix this is to use a structural stapler.

The membrane layers are laid with a slight overlap, and the edges are laid using adhesive tape.

The design of the cold attic roof is such that it can be used in regions with any climatic characteristics. Many people believe that this type of roof does not apply to the northern regions, although in fact this is not the case. Cold attic rooms are often installed in such regions.

The attic is insulated, and the cold roof does not affect the internal microclimate of the upper floors. The attic cannot be used because installing an insulating layer between the top floor and the space under the roof eliminates all the nuances that affect heat loss.

When installing a cold metal roof, measures must be taken to insulate vents, chimneys, and attic outlets.

This way, you won't have to worry about condensation buildup, icing, heat loss or rain and melting water.

A cold roof can be covered with almost all roofing tiles, and due to the ease of installation metal roof is used much more often.

Some other types roofing materials, especially soft roofs, also work well in this situation, but they require a lot of time and money to install.

Roof structure for metals, including waterproofing

To block cold attic With metal roofing, the most convenient and easiest way to install a roof.

In this case, the roofing cake consists of waterproofing material, which is attached to the raft frame, slats and roofing coverings ( metal tiles). In fact, the application of such a coating occurs very quickly. The insulating film is fixed with staples or nails, and then additionally pressed with thread, and self-tapping screws are screwed in. The installation of rail guides is carried out taking into account the dimensions of the metal plate.

The cabinet plate is made from dimensions ranging from 25 to 100 mm, and sometimes plywood or particle board if you need hard floors.

The installation of film or membrane for attic waterproofing is loose, with some stretch.

However, it makes sense to ensure that the integrity of the coating is not interrupted, that is, any holes or cracks are excluded. As a rule, the film can be stretched by 15-25 mm. This ensures ventilation of the interior. waterproofing membrane, condensed moisture is removed at the handle and further into the drain. Ignoring such a simple rule will ultimately lead to premature deformation of the roof frame and the entire roof.

Feature of metal tiled roof is that cold roof film cannot reduce the noise that occurs when metal falls on heavy rains.

Therefore, living spaces with such a coating provide a layer of thermal insulation that absorbs strong noise. Without this layer, as a rule, only rooms for self-contained attics are equipped.

Thus, a cold roof will include the following layers:

• A cold roof vapor barrier is installed inside, which only releases moisture and prevents it from entering the living room.
• Then install the raft frame for the roof.
• The next layer is a waterproofing material.

  The film is laid with a recess to drain condensate.

• A control grille is then attached, which compresses the waterproofing, secures it and provides ventilation holes.
• The post is then filled to repair the roof.

  It is made of 50 x 50 mm blades and laid along ramps divided into 35-45 cm. Depending on the type and extent of the roof beam, the pitch and thickness of the panel can be changed.

• The rear floors are made of metal.

Tools and accessories for installing a cold attic

It is worth noting that you will not need overly complex professional Building tools for laying metal tiles.

You can use the basic set that every housewife has in her home.

In addition to the frame frame, frames, slats and counterflow flasks require membrane or foil insulation for vapor and waterproofing, as well sufficient quantity metal tile sheets purchased from the same series.

All elements are secured using clamps, self-tapping screws, galvanized nails and even anchor bolts.

However, it should be remembered that they must be High Quality so that the roof does not deteriorate ahead of time.

Concerning roof roof, That evaluation lists glued, required roof valley (internal and external), wreaths, wind and snow stations and watercourses.

The main difference between cold roof and heat lies in the presence in the back layer of thermal insulation material located between the layer of water and the vapor barrier.

The main functions of the attic vapor barrier layer
Types of vapor barrier materials - which one is better to choose
Polyethylene films
Polypropylene films
Vapor barrier reflective membranes
Rules for installing vapor barriers

Thermal insulation of the attic is a very important process, since a large amount of heat escapes through the roof and walls.

To reduce the loss of thermal resources, it is necessary to carefully consider the structure of the roofing pie and ensure the effective functioning of each layer.

An important role in this process is played by the attic vapor barrier, since this layer does not allow moisture to penetrate into the insulation and to wooden elements rafter frame, thereby extending their service life without loss performance characteristics.

The main functions of the attic vapor barrier layer

To answer the question of which vapor barrier to choose for the attic, you need to know its purpose.

When warm and cold air flows combine, steam and condensate always form, the accumulation of which certainly leads to a decrease in the performance characteristics of any, even the most reliable building material.

Wood rotting reduces the strength of the entire structure, which becomes the reason for repairs or complete replacement main parts of the structure. In addition, high humidity promotes the formation of mold and fungi, which release toxic substances.

As a result, the person may feel unwell and headache, and even allergies.

The joint work of insulation and vapor barrier not only prevents the penetration of steam, but also retains maximum heat in the attic room.

Types of vapor barrier materials - which one is better to choose

Can be used as a vapor barrier layer various materials, including roofing felt, glassine and various films.

The most popular today are polyethylene and polypropylene films, as well as vapor barrier membranes. To understand which vapor barrier is best for the attic, you should get acquainted with the basic materials.

Polyethylene films

This material is laid during the installation of the roof, prerequisite use is to create gaps for ventilation.

This will prevent the formation of condensation, since polyethylene is not capable of allowing air to pass through. Laying with the rough side facing out promotes the evaporation of steam particles.

Polyethylene film can be used for vapor barrier and waterproofing thanks to universal characteristics. Reinforcement with a special metal mesh helps increase the strength of the material.

Polypropylene films

High durability and strength are the main characteristics of this material, but at the same time it has one significant drawback.

How to choose a vapor barrier for an attic roof

The upper side of the reinforced film is covered with drops of condensation. If the choice of vapor barrier for the attic is made in favor of this material, then laying an additional layer of viscose or cellulose, which absorbs fumes, will help solve the problem.

Vapor barrier reflective membranes

This insulation does not require ventilation gaps, since the structure of the material is capable of allowing air to pass through and retain moisture.

In addition, the membrane is characterized by high quality and reliability. The attic vapor barrier should be installed on top of the insulation.

In addition, a vapor barrier is installed using isospan or penoplex.

These are high quality materials, characterized by a low thermal conductivity coefficient, excellent waterproofing and vapor blocking properties. One of the advantages of their use is operation at high temperatures.

Rules for installing vapor barriers

A reflective vapor barrier for the attic, installed in accordance with all the rules, can protect the insulation from moisture penetration and preserve its performance qualities.

First, you must first seal and insulate the main structural elements and all protruding parts of the structure.

Secondly, the method of attaching the vapor barrier material depends on the type of surface. The material is attached to concrete, bricks or blocks using double-sided adhesive tape. On wooden surfaces The vapor barrier is fixed using nails or a construction stapler.

Thirdly, when using foil vapor barrier for the attic, the reflective layer must be turned inward.

Fourth, for maximum effectiveness, a vapor barrier should be used without damage. And during the installation process, the material should be tensioned to avoid sagging.

Internal insulation of an attic is one of the most difficult construction tasks. And all because the result is important here: how the roofing pie will behave in winter, whether there will be any leaks, whether there will be a smell of dampness, and whether it will all have to be dismantled later. Why such difficulties? The fact is that no matter how carefully the budget for building a house is planned, as a rule, it is still not enough for everything. To the point that even the owners of the future family home decide to buy laminate flooring cheaper - just to finish the repairs and just start living. And the most popular expense item, which is immediately cut as soon as the lack of funds becomes clear, is attic insulation. “Later, in the future,” the owners promise themselves, especially since insulating the attic from the inside is not a problem at all, and you can start it at any time, even in winter.

In fact, there are a lot of subtleties and nuances here, and therefore, if you have already taken up this matter, carefully study this article. And everything will work out!

Why do problems arise?

There are statistics: up to 30% of attics have to be remodeled after the first winter. The roof covering, interior trim and films are removed, and the insulation is dried. In this case, a lot of materials have to be thrown away, and this is another unplanned expense. Even if you hired a professional team of builders, this is not a guarantee of the well-being of the future attic, especially if the roofing cake is thought out without taking into account the peculiarities of the local climate.

Why is this happening? So, in Russia there is dampness, cold and 24-hour negative temperatures- Not unusual. The lower the temperature external environment, the greater the volume of steam that penetrates the vapor barrier - all due to an increase in the partial pressure difference. And at the same time, the migration of moisture through the cold membrane slows down significantly, although it does not stop. Bottom line: the situation is even worse than under standard tested conditions. And therefore, you cannot test the vapor permeability of a roofing pie in European conditions and expect the same good result in the Siberian regions.

Here's a simple illustration to help you understand what we're talking about here:

Note that the maximum water vapor pressure on the roofing pie is in the residential attic. And it’s not even that there are people in such a room much more often than in an ordinary cold attic - it’s just that the pressure of warm air is additionally added to the steam pressure. Moreover, these processes are so obvious that they can be observed in the form of real leaks!

The fact is that wet insulation loses its properties very quickly. And the more humid the air that reaches it, the faster the thermal insulation decreases. For example, basalt insulation with a humidity of only 5% already loses its heat by 20% than dry insulation.

For example, just one cubic meter of air space, if its relative humidity is 100%, at a temperature of 20C contains 17.3 grams of water - simply in the form of steam. And the lower the temperature, the more difficult it is for air to hold water in a bound state. And when the temperature drops to 16C, there will be only 13.6 grams of water vapor in the same air, and the rest will settle as water in the insulation. Let us conclude: moisture in the insulation appears due to the condensation of excess water vapor from the air as the temperature decreases. And it must be actively fought. And this is far from the only problem - now we will deal with them all.

Let's start insulation - work technology

Let's start with the first problem - insufficient thickness of the joists if you insulate the attic after the construction of the entire house and installation of the roofing. Why is that? Let's take a closer look at this issue.

Thus, attic insulation can be divided into basic and additional. Basic is insulation, which is carried out during the construction of the roof of the house and involves the use of lightweight insulation directly in truss structure. And here additional insulation is already turning an uninhabited attic into a full-fledged attic.

With basic insulation the main task– to minimize the heat loss of the house through the roof, and such basic insulation may well replace additional internal insulation, if only you choose the insulation wisely, do not skimp on its thickness and think through the rafter system well. This is often done by those builders of their own houses who understand that 20 rooms may not be enough in the future, and additional space for a billiard room, library or sauna cannot interfere. And therefore, it is better to initially build it completely residential, and not finish something later.

But, if during the construction of your house you decided to make do with basic thermal insulation and now you have enthusiastically taken up the task of arranging a habitable and cozy attic, then the only option for you is additional internal insulation with all its nuances, the main one of which is the insufficient thickness of the rafters, which were not originally designed for dense internal insulation. But the problem is completely solvable, as proof of which we have prepared for you detailed master class:

Now let’s move on to more insidious aspects that are no less important: proper vapor barrier and waterproofing, which you may have to redo.

No - dampness and smudges!

For any insulation, it is extremely important to create the right conditions, otherwise the material will quickly become damp and, instead of a source of heat, become a source of dampness, mold and cold. What are these conditions? Let's take a closer look!

What is dew point?

The first and most important quality of any insulation is low thermal conductivity. Thanks to it, the insulating layer rigidly separates warm air inside from the cold outside. It would seem that they inserted insulation into the rafters, secured it - and that’s all that else is needed? Not so!

Firstly, with outside the whole thing needs to be carefully waterproofed from rain and damp air, because... In this regard, such a roofing pie is a real sponge. Secondly, any insulation also has a second quality - vapor permeability, i.e. "breathes". Now let’s remember physics: the warm, humid air inside the room under the roof (always humid!), without finding an obstacle, easily passes inside the insulation and collides with its colder part, the one that is closer to the roofing pie. And there this air condenses, settling in the form of droplets, which is called the dew point. What's the point of external waterproofing then? Mineral wool insulation is especially susceptible to this phenomenon, note.

Therefore, our first task is to ensure that as little steam as possible passes through the insulation, because even super-diffuse membranes in the cold do a poor job of removing water vapor, due to a significant slowdown in moisture transfer processes. And this is a question of proper vapor barrier of the attic insulation.

Here clear example What unpleasant consequences does ignoring the concept of dew point lead to:

Vapor barrier: warm European winters and Russian frosts

In fact, in Western Europe, where winters have always been mild, there is no need for vapor barriers with special properties - simple packaging films are quite suitable. So they sometimes end up in Russia, although their vapor barrier properties are not high. These are LDPE roll films, which stands for “low density polyethylene”. In such films, uneven thickness and microdefects are noticeable. Their main purpose is product packaging.

Little better are reinforced materials, which are made by hot pressing a film onto a mesh of twisted thread. In production, such films are injured by mesh nodes, and as a result, the low vapor barrier properties are further reduced. Although the film itself turns out to be much stronger than usual, of course.

More reliable are bag fabrics made from polypropylene threads and spunbonds. The former are additionally laminated with molten PEPN, but a uniform and continuous film is still not obtained, although the strength is pleasing. And the latter are made from non-woven polypropylene fiber, but its vapor permeability is still in the range of 15-25 g/m2 per day, and this is a very low figure.

And aluminum foil boasts the best vapor barrier properties, which is even suitable for arranging steam rooms in which the pressure and volume of water vapor are the highest. The only point: such a vapor barrier additionally creates the effect of a thermos in the attic, simultaneously reflecting invisible heat rays back into the room. That’s why it’s better not to insulate a small attic room this way, but for a spacious one it’s just the same.

Therefore, if you want to save heat as much as possible, or you are planning to make a good sauna in the attic, then you need the following vapor barrier:

Or immediately purchase insulation with an aluminum side:

We close access to water vapor

But remember that it is still important to properly lay and waterproof a good vapor barrier film, otherwise water vapor will still find its way in.

The joints of vapor barrier sheets are usually sealed with a special adhesive tape made of butyl rubber, but even in this case complete tightness cannot be guaranteed. The thing is that over time, the adhesion of the sticky layer decreases, and with additional load the canvases come apart. That's why when installing exterior finishing, when it is possible to attach the same drywall directly to a vapor barrier, many people install additional sheathing. Its task is not so much to ensure that the finish is fixed more evenly (which is also important), but rather to press the tape or sealant with the slats.

In addition, this sheathing (usually with slats up to 3 cm thick) additionally allows you to lay electrical wires directly under the sheathing, and not through the insulation, as many do and which can hardly be called a technically competent solution.

But the places where the vapor barrier adjoins the passing pipes and brick walls must be insulated with special sealants or tapes.

Another important point: never tighten the vapor barrier - fasten it with a small margin. The fact is that all wooden structures, which is rafter system, naturally dry out and become slightly smaller in size. The frame itself becomes mobile, and there is a risk of ruptures under the roof outside and under the sheathing inside. And then - surprise!

Does external waterproofing “breathe”?

So, with warm inside Insulation we install a vapor barrier, which does not allow moist air to enter from the room. And on the outer, colder side we are already attaching waterproofing, which will protect the insulation under the roofing pie from external accidental leaks of melt water or rain.

And the further development of events depends on how “breathable” the upper one turns out to be. waterproofing film. So, if you purchased the most ordinary roll of inexpensive waterproofing, things are bad, the moisture from the roofing cake will evaporate for a long time and difficultly, as a result - dampness and gradual destruction of the insulation. But modern vapor-permeable membranes are called “smart” for a reason: they do not let moisture in, but remove water vapor out. It's all about their unusual, well-thought-out structure. This is why it turns out that when using cheap barrier films, even expensive insulation does not last long, and repairs are not far off.

Please note that the diffuse membrane should fit as tightly as possible to the insulation, without any gap, like with a regular film. Otherwise, the membrane material will cool more strongly, and the temperature will become lower than the steam migrating through the insulation. You will see the result in the form of ice directly on the membrane, which will cause it to lose its vapor-permeable properties even more.

When do you have to dismantle the roof?

Quite often during the construction process, roofing material or reinforced films are installed as roof waterproofing. And a couple of years later, when the attic turned out to be very necessary and everyone at home enthusiastically began to repair it, it turns out that without full analysis the roof won't work anymore.

What's the matter? The fact is that such waterproofing does not “breathe” at all, and any insulation under it will completely bend. That’s why, if the roof of your house is still under construction, but you are thinking about putting off insulating the attic for the future, immediately use a good super-diffuse membrane as waterproofing.

But how can something get into the insulation if we have already installed a vapor barrier? The fact is that not a single film in the world is capable of retaining water vapor 100% - they are very small. And no matter how hard manufacturers try, there is no absolute barrier. And even more: modern vapor barrier films actually don’t even do half the job, and only the highest quality ones are capable of retaining steam by 75-80%. Everything else, unfortunately, penetrates inside the roofing pie.

Let's sum it up ogi. You should end up with a roofing pie with two films that have absolutely opposite properties: the inner one does not let steam into the insulation, and the second one saves it from a small amount that accidentally gets there.

Insulation of complex structural elements

If you have decided on insulation and insulation materials, congratulations! Prepare everything carefully, calculate everything you need and feel free to proceed. Main, installation work Exercise only in a well-ventilated area. And finally, when working with modern insulation materials Many manufacturers advise using a vacuum cleaner before insulating the attic roof from the inside, and after finishing.

Insulating pitched and straight attic walls is not difficult, and the first difficulty you will encounter is windows and other complex structural elements. It is also important to properly insulate them, leaving no chance for moisture or water vapor to leak through. Do you know what are usually the most problematic places in attic rooms that cause mold and smudges? So take this issue seriously:

Here is another tricky moment when the attic ceiling is not made of logs, but a solid slab. You need to insulate it like this:

And finally, after insulating the attic, make sure that snow does not accumulate later in the drains and on the ridge - the entrance and exit of the movement of under-roof air. For this purpose, it is more rational to install ventilation pipes along the entire roof ridge, and make the ridge itself unventilated. That's all the difficulties!

Thermal insulation of the attic is a very important process, since a large amount of heat escapes through the roof and walls. To reduce the loss of thermal resources, it is necessary to carefully consider the structure of the roofing pie and ensure the effective functioning of each layer.

An important role in this process is played by the attic vapor barrier, since this layer does not allow moisture to penetrate into the insulation and to the wooden elements of the rafter frame, thereby extending their service life without loss of performance characteristics.

The main functions of the attic vapor barrier layer

To answer the question of which vapor barrier to choose for the attic, you need to know its purpose. When warm and cold air flows combine, steam and condensate always form, the accumulation of which certainly leads to a decrease in the performance characteristics of any, even the most reliable building material.

Wood rotting reduces the strength of the entire structure, which becomes the reason for repair or complete replacement of the main parts of the structure. In addition, high humidity promotes the formation of mold and fungi, which release toxic substances. As a result, a person may experience malaise and headaches, and even allergies.

The joint work of insulation and vapor barrier not only prevents the penetration of steam, but also retains maximum heat in the attic room.

Types of vapor barrier materials - which one is better to choose

Various materials can be used as a vapor barrier layer, including roofing felt, glassine and various films.

The most popular today are polyethylene and polypropylene films, as well as vapor barrier membranes. To understand which vapor barrier is best for the attic, you should get acquainted with the basic materials.

Polyethylene films

This material is laid during the installation of the roof; a prerequisite for use is the creation of gaps for ventilation. This will prevent the formation of condensation, since polyethylene is not capable of allowing air to pass through. Laying with the rough side facing out promotes the evaporation of steam particles.

Polyethylene film can be used for vapor barrier and waterproofing due to its universal characteristics. Reinforcement with a special metal mesh helps increase the strength of the material.

Polypropylene films

High durability and strength are the main characteristics of this material, but at the same time it has one significant drawback.

The upper side of the reinforced film is covered with drops of condensation. If the choice of vapor barrier for the attic is made in favor of this material, then laying an additional layer of viscose or cellulose, which absorbs fumes, will help solve the problem.

Vapor barrier reflective membranes

This insulation does not require ventilation gaps, since the structure of the material is capable of allowing air to pass through and retain moisture. In addition, the membrane is characterized by high quality and reliability. The attic vapor barrier should be installed on top of the insulation.

In addition, a vapor barrier is installed using isospan or penoplex. These are high quality materials, characterized by a low thermal conductivity coefficient, excellent waterproofing and vapor blocking properties. One of the advantages of their use is operation at high temperatures.

Rules for installing vapor barriers

A reflective vapor barrier for the attic, installed in accordance with all the rules, can protect the insulation from moisture penetration and preserve its performance qualities.

Firstly, you must first seal and insulate the main structural elements and all protruding parts of the structure.

Secondly, the method of attaching the vapor barrier material depends on the type of surface. The material is attached to concrete, bricks or blocks using double-sided adhesive tape. On wooden surfaces, the vapor barrier is fixed using nails or a construction stapler.

Thirdly, when using foil vapor barrier for the attic, the reflective layer must be turned inward.

Fourth, for maximum effectiveness, a vapor barrier should be used without damage. And during the installation process, the material should be tensioned to avoid sagging.

The attic in the house has its advantages and disadvantages. Which? About this As the voting results show (), a house with an attic attracts approximately 50% of readers.

Work on insulating the attic is carried out either from above before installing the roof covering, either from below, after the house is protected from precipitation.

The first option is from above, it is more convenient to install, and allows you to carry out work faster and with better quality.

With the second option - from below, you can postpone the work and costs of arranging the attic until later.

The designs of insulated roofs in both cases are somewhat different.

Insulating the attic from above

In this article, the use of steam-wind-moisture barrier membranes in the construction of an insulated roof attic floor Let's look at the example of a system of protective materials trademark Izospan. You can read about the materials of this system in the article.

Installation of an insulated attic roof

1. Roof covering
2. Wind- and moisture-proof film Izospan AS, AM
3. Counterrail
4. Insulation
5. Vapor barrier Izospan B
6. Rafter
7. Interior decoration
8. Lathing

Scheme for protecting attic insulation from wind, moisture and condensation in Fig. 2

Wind and moisture protection of attic insulation

Fig.2. To protect the attic insulation from wind, moisture and condensation, a ventilated gap is arranged, and films and Izospan membranes are laid below and above.

Why protect insulation from wind?

Mineral wool insulation, which is usually used for roof insulation, has an open porous structure.

Air moving in the ventilated gap easily penetrates the insulation, blowing heat out of it. The effectiveness of thermal insulation due to air infiltration can be reduced by almost half.

In addition, air moving under the influence of wind in the gap tears off and carries away particles of insulation. Weathering of the insulation occurs - over time, its density and thickness decreases, the insulation becomes a source of dust, which can penetrate into the house.

To prevent these processes, the insulation on the top side of the ventilated gap is covered with windproof, vapor-permeable material.

In addition, the wind-moisture-proof membrane (item 2 in Fig. 1) protects the insulation and load-bearing structural elements from under-roof condensation, snow and atmospheric moisture, which can be blown into the gaps of the roofing covering or penetrate into the joints of roofing sheets due to capillary suction.

The wind-waterproof membrane should not prevent steam from escaping from the insulation (vapor permeability of at least 750 g/m 2 per day).

In the construction of an insulated roof, it is recommended to use vapor-permeable materials as waterproofing and wind protection. roofing membranes Izospan AM or Izospan AS. Materials Izospan AM and Izospan AS laid directly on the insulation without a ventilation gap between them.

Izospan AM and Izospan AS are not intended for use as a main or temporary roofing covering for the period of installation.
Izospan AM and Izospan AS are laid with the white side facing the insulation.
When installing an insulated roof, Izospan AM (Izospan AS) is rolled out and cut directly on top of the insulation. Installation is carried out with horizontal panels overlapping, starting from the bottom of the roof. Overlapping panels at horizontal and vertical joints - at least 15 cm.

The stretched material can be further strengthened on the rafters with staples using a construction stapler.

On top of the material, 4x5 wooden antiseptic counter-battens are attached vertically along the rafters. cm on nails or screws. The place of the vertical overlap or the junction of two horizontal panels must be pressed against the rafters with a counter batten.

Lathing or continuous plank flooring is mounted along the counter-battens, depending on the type of roofing.

For weathering water vapor and roof condensation a ventilation gap must be provided between outer side material Izospan AM (Izospan AS) and roofing covering for counter-batten thickness 4-5 cm.

In addition, to ensure ventilation of the under-roof space ventilation holes are provided in the lower part of the roof and in the ridge area for air circulation.

The material Izospan AM (Izospan AS) is fastened in a tense position so that water can roll freely over its surface. The bottom edge should provide a natural drainage of moisture from the surface of the membrane into the gutter.

Vapor barrier for attic insulation

The vapor barrier film (item 5 in Fig. 1) performs several functions at once:

1. Protects the insulation from penetration of water vapor from the attic room. From the article you can learn why, without a vapor barrier, insulation will accumulate moisture and collapse.
2. In addition, vapor barrier performs another function - it reduces heat loss.
3. The material protects the living space from the penetration of microfibers (dust) of the insulation.

Izospan B used as a vapor barrier in insulated roofs of exploited attics with various types roofing covering.
When installing an insulated roof, the Izospan V vapor barrier is mounted on the inside of the insulation on the rafters or along the rough sheathing using a construction stapler or galvanized nails. Installation is carried out from bottom to top with horizontal panels overlapping with overlap at horizontal and vertical joints of at least 15 cm.

When finishing a room with clapboard (plywood, decorative panels, etc.), the vapor barrier is secured along the frame with vertical antiseptic wooden slats 4x5 cm., and when finishing with plasterboard - galvanized profiles.

The material is installed with a tight fit with the smooth side to the insulation, with the rough side down. The interior decoration of the room is attached to a slatted frame or galvanized profiles with a ventilation gap of 4-5 cm.

To ensure the tightness of the vapor barrier, it is recommended to fasten the panels of Izospan B material together with Izospan KL or SL connecting tape. Places where Izospan materials meet wooden, concrete and other surfaces are glued with Izospan ML proff adhesive tape.

Instead of Izospan B, Izospan RS, Izospan C or Izospan DM can be used as a vapor barrier when installing an insulated roof. The installation diagram is similar.

Heat-reflecting vapor barrier for attic insulation

Can be used as a vapor barrier heat reflective vapor barrier: Izospan FS; Izospan FD And Izospan FX. The material is mounted on the inside of the insulation (on the rafters or along the rough sheathing using a construction stapler or galvanized nails) with the metallized surface facing the room.

In front of the metallized surface of the membrane there must be air gap 4-5 cm. Only in this case does it happen reflection of heat flow, which increases the thermal resistance of the coating. Installation is carried out with horizontal panels overlapping, starting from the bottom of the roof. Overlapping of material at horizontal and vertical joints - at least 15 cm(Izospan FX - end-to-end).

Vapor barrier sealing

The vapor barrier layer prevents the insulation from getting wet. In places with defective vapor barriers, the insulation becomes saturated with moisture in winter. These places begin to freeze, fungus and mold appear on the walls, and the insulation itself gradually deteriorates.

Careful sealing of the vapor barrier layer is a necessary condition for long and reliable service of thermal insulation and wooden roof parts. The same thing happens if water gets into the insulation from above. But developers, due to misunderstandings, often neglect the threat of moistening the insulation from below, from inside the room.

TO wooden parts The vapor barrier film is secured using staples with a stapler. It is glued to the metal profiles of the sheathing on Double-sided tape. The vapor barrier film is laid with 10 cm. overlap. The film should not be stretched too much, since the film changes its size when the temperature changes.

The joints of the film are taped with tape made from a material with a similar coefficient of thermal expansion. The junction of the film to the walls is more reliable press with planks and apply sealant underneath them to the wall, since on rough surfaces adhesive tapes They don't hold up well.

It is more reliable to make film joints over a hard surface, where, in addition to gluing, the joints can be pressed with spacers, sheathing bars, secured with staples, etc. Passages through the vapor barrier of chimneys and ventilation pipes are also carefully sealed. Don't neglect sealing plumbing piping and electrical wiring.

Choosing insulation for the attic

To insulate the attic, it is recommended to choose fireproof mineral wool insulation. In summer, the roof can heat up to 60 degrees C, and in winter, up to 25% of the heat can escape through a thin layer of wet insulation. Therefore, it is so important to lay a sufficient layer of insulation and prevent it from getting wet.

Modern energy saving standards recommend providing the attic roof with a heat transfer resistance of 4-5 m 2 *K/W. In order to obtain the economically justified heat transfer resistance required by the standards, it is necessary to lay layer of mineral wool insulation 20 - 25 thick cm.
How to calculate the thickness of attic insulation

The height of the roof rafters, as a rule, does not exceed 15-18 cm. Additional layers of thermal insulation are placed between the bars of the internal sheathing, or bars of the required height are nailed to the rafters from below.

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Mineral wool

Soundproofing the attic

In addition to good thermal protection, the outer fencing of the attic must provide sufficient sound insulation of the attic rooms from airborne noise. People sleeping in the attic should not be awakened by the impact of raindrops or hail on the metal roof covering.

Therefore, the external fencing of the attic is subject to fairly stringent sound insulation requirements.

In accordance with current standards, the airborne noise insulation index of the external fence of the attic - Rw, must be at least 45 dB. The same mineral wool insulation is used as sound insulation and against airborne noise as for thermal insulation.

To achieve this indicator in the external enclosures of the attic the thickness of mineral wool sound insulation must be at least 250 mm. If the thickness is less, then the sound insulation will not meet the standards. Thus, the thickness of the mineral wool thermal and sound insulation of the attic is selected based on two conditions: thermal insulation and sound insulation. The thickness is the greater of the two indicated.

Insulating the attic when working from the inside

Features of the attic insulation design when performing work from the inside, under the installed roofing, are clearly visible in the figure below (to zoom in, press the Ctrl and + keys simultaneously):

If the ceiling of the upper floor in the house is made according to wooden beams, then the floors and partitions in the attic should be light in weight and provide the necessary sound insulation. In this case, it is best to make it with gypsum fiber sheets (GVLV) or other boards, and also install it. Just such an option is shown in the figure.

Please note that the frame partition should cut through the attic sheathing as far as possible, and the base of the partition should rest on the subfloor. This design will prevent sound transmission to the adjacent room bypassing the partition, through the finished floor covering and attic cladding.

If not accepted special measures, That soundproofing of attic rooms with frame external walls, partitions, floors and ceilings will be insufficient.

If the ceiling of the upper floor in a house with an attic is made of reinforced concrete slabs or, then on such a floor it is more profitable to lay partitions made of brick, as well as light gypsum or concrete building blocks.

Watch the video, which clearly shows the thermophysical processes in an insulated roof and the basic installation rules. While watching the film, remember the need for wind protection with mineral wool insulation.

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Materials used in the construction of roofs and arrangement of premises with non-standard temperature and humidity conditions operating mode, are endowed by manufacturers with special properties. They not only easily resist the attacks of steam-saturated hot air, but also create a “thermos” effect, due to which energy consumption for heating is greatly reduced.

These specific products include foil vapor barrier, the installation of which allows you to solve a lot of important problems in the construction of building structures.

Foil materials used in vapor barrier devices are complex products with a layered structure. Their base is made of polypropylene fabric, lavsan, fiberglass and similar options that are resistant to tearing, as well as chemical and biological aggression.

Using durable woven or non-woven polymer base allows you to create a reliable base for metal foil that is fragile by nature. At the same time, it was possible to provide easy-to-install flexibility. The composition of the thermoplastics used in the manufacture eliminates the possibility of decay and the spread of fungal colonies.

On the working side, vapor barrier materials of this category are backed with a metallized film. Thanks to the method of applying foil coating, all positive traits both the polymer base and aluminum foil, which copes “excellently” with three very significant functions:

• Insulation from steam and precipitation. Foil materials ideally protect the insulation of a roofing pie or wall insulation system from the penetration of steam coming from inside the house being furnished, and from atmospheric water tending to penetrate from the outside.
• Reflection of thermal radiation. The metallized coating serves as a reflector, interrupting the flow of heat waves outside the heated room and redirecting the stopped heat in the opposite direction.
• Wind and UV protection. Vapor barrier films with foil act as a strong barrier against wind, tending to remove heat from the cotton insulation. Installed with the working side out, they are in summer heat reflect the sun's rays from the attic roof.

Using a vapor barrier with foil allows you to significantly save on heating bills and turn on the air conditioner less often.

Scope and methods of application

The structure and properties of foil vapor barrier materials have significantly expanded the scope of application. These materials are used in insulated roofs, in our latitudes they are most often installed on the inside of the roofing pie, in the south they are mounted above the insulation. In houses with an unfurnished attic, foil protection is installed in combination with waterproofing.

In addition to the traditional purpose of protecting ceilings and space from vapor residential attics they are used as a substrate for all types of floor coverings and systems heated floors, as well as in insulated structures frame walls. They are installed in the form of a screen that reflects heat flows from heating devices and heating units.

In order for foil materials to perform a reflex function, it is important to properly arrange the system. A non-ventilated air gap 2–3 cm thick should be formed between the inner lining of the attic, the walls, the ceiling of the steam room and the metalized coating.

When using a flat or mansard roof as a heat-reflecting screen, a standard ventilated gap of 3–4 cm is left between the metalized coating turned outward and the roof. The goal here is not to conserve thermal energy. Everything that is reflected from the foil can be freely released into the atmosphere along with condensate and steam that has penetrated into the thermal insulation.

The gaps necessary to ensure ventilation and to maintain a distance between roofing materials of different compositions are formed by installing lathing from a bar or metal profile. Laths are installed in accordance with the type of roofing, the slope of the slopes and the calculated load on the rafter structure.

Benefits of Using Foil Insulation

The undeniable insulation priorities of materials in which water-repellent material is combined with foil are complemented by an impressive list of convincing advantages, these are:

• Lightness. The installation of a vapor barrier does not in any way affect the weight of the structure as a whole and does not force measures to be taken to strengthen the foundation.
• Minimum thickness. Laying a vapor barrier layer does not affect the thickness of the roofing pie at all. When using materials with anti-condensation properties, there is no need to create a distance gap between the vapor barrier and the sheathing.
• Flexibility. The installation of a vapor barrier is easy; there are no problems even when laying it on complex forms. It bends around convex and concave corners and rounded surfaces without any problems.
• Manufacturability. Rolled materials can be easily cut with ordinary sharp scissors or a construction knife.
• Environmental Safety. In the manufacture of vapor barrier films are used starting materials, not posing a threat environment and owners of the structures being developed.

Produced in a wide range of vapor barrier options with foil, they do not absorb moisture at all and are characterized by zero porosity. Their long-term operation in damp rooms does not threaten the materials with rotting. An important advantage is its multifunctionality, thanks to which the same film can protect several adjacent structures, creating a continuous sealed barrier.

Foil protection installation technology

Let's look at the most common technological options for using vapor barrier materials with foil. In the format of our website, the situations under consideration include the arrangement of a warm attic and a cold attic. In the first case, the insulation system is installed along the slopes, in the second - along the ceiling.

Since the main purpose of vapor barrier films is to protect the insulation, their place in the system is determined by the position of this particular component of the roofing pie. Those. V attic structures The vapor barrier is installed along the slopes; in houses with a cold attic, it is laid on the top of the attic floor or attached from below under the ceiling sheathing.

To properly install a vapor barrier, you should adhere to generally accepted rules:

• The vapor barrier of the slopes should be a continuous moisture-proof carpet that absolutely excludes the penetration of moisture or eliminates the possibility to the maximum extent. For this cloth roll material are hermetically connected with tape.
• Strips of vapor barrier material are laid strictly horizontally. The starting plate is attached to ridge girder, the following is superimposed on it so that the edge of the panel located below overlaps the edge of the already installed strip on the side of the room being finished.
• Vapor barrier material for wooden floor from the attic side they are laid in strips extending onto the walls and vertical coverings 15 - 20 cm each. The result should be something like a pallet with sides.
• The material is rolled out onto the surface to be constructed in the same way as the roll was formed by the manufacturer. The installation side must be indicated on the vapor barrier; it cannot be changed at your own discretion.
• Fastening the material on pitched roofs is done from the inside of the rafters using a stapler, and if necessary, with slats. If fixation involves the use of a block, then a counter-lattice under the sheathing is installed on top of it.
• In systems with open rafters, a vapor barrier is placed along the outer ribs of the rafter legs, then rigid slab insulation is installed. The material is fixed with a stapler.
• In insulation schemes with extruded polystyrene foam during installation living rooms with traditional operating mode, i.e. without vaporization and impact high temperatures, it is permissible not to use a vapor barrier layer.

To arrange the ceiling from the ceiling side, it is advisable to select self-adhesive materials. In thermal insulation systems attic floors with backfill insulation, for example, with expanded clay, it is permissible not to glue the vapor barrier strips with tape, because they will be loaded.

When arranging the attic floors of houses with cold attics, a vapor barrier carpet is built over the floor, and waterproofing is placed on the roof slopes. In this scheme, the insulation is washed air currents created by natural ventilation, therefore any insulating layer above it will only interfere with the removal of moisture.

And further. When using foil insulation, it is important to select accessories from the same company as the material itself. There are, of course, universal adhesive tapes that can connect any type of material, but... systems with increased requirements for tightness are constructed from insulation with foil, it is better not to experiment with options for gluing tapes.

Overview of leading foil options

In order to choose a suitable vapor barrier film for arranging an attic or ceiling, you need to familiarize yourself with the popular and practice-tested product options from different companies.

Energy saving film DELTA®-REFLEX

Delta brand products have proven themselves excellent in the construction of roofs and have earned an impeccable reputation among roofers. The reflective coating of the material located on the working side is created by spraying. A polyester film is applied over the spraying, protecting the aluminum layer from damage and shedding. The reflection coefficient is 50%.

The film of this brand does not lose flexibility at sub-zero temperatures and can be used in a steam protection device both outside and inside the house. Approved for use in all types of wet rooms. Along the edge of the sheets of a similar film, but with the addition of the word PLUS in the marking, there is a self-adhesive tape, which significantly facilitates the work of installers.

Reflective material Izospan FD

More humane in terms of price, but less resistant to the realities of roofing adversities, the material labeled Izospan FD is a two-layer composition of polypropylene fabric with an aluminum coating applied to it.

Inferior to the previous representative in terms of strength indicators, but ahead of energy saving characteristics: coefficient determining thermal reflection is at least 90%. Attracts with its affordable price and stable availability in the retail chain. The technical data sheet of the film indicates the temperature range from -60º to +80º.

Super strong version ARMOFOL® type A

Foil vapor barrier with the specified logo is made on the basis of fiberglass mesh. The scope of use is no different from the types described above, but the product’s temperature operating range is significantly expanded. The material is capable of flawlessly serving at temperatures down to -60º, in which it is 20º ahead of Delta. The limit in the positive segment is + 150º, which is already 70 more confident units.

Along with its competitor, Armofol can be used in new construction and in carrying out restoration work when repairing roofs, basement and basement structures, steam Russian baths, swimming pools, bathrooms, saunas. The thermal reflection coefficient reaches 90 – 97%.

Video about the features of foil insulation

Once again about the breadth of application of insulating films with foil:

Information about the use of foil vapor barrier film in construction is needed not only by independent craftsmen. It will help to competently monitor the work of hired roofers. Correctly laid material guarantees long-term operation favorite furnished property.