Is there a need for vapor barrier in a cold attic? Vapor barrier and moisture and wind protection for a cold attic: basics of application and installation

Owners of private houses very often observe the formation of condensation on ceiling covering. The reason for this is cold attic. The simplest and effective solution This problem is considered to be the installation of a vapor barrier.

Peculiarities

The construction of almost any house involves the design attic spaces various types. The simplest are cold attics, which are unable to maintain the temperature at the same level.

This design consists of several main parts:

• Roofing covering. In most cases, there is no insulation here, and only the insulation itself is used. finishing material for protection from rain.
• Exterior walls.
• Overlap. Warm attic can be supplemented with a layer of insulation.

What is it for?

Vapor barrier is a special material that is not capable of allowing moisture to pass through. These products are designed to protect insulation, as well as internal surfaces in the house from possible moisture penetration.

If not used this material, then a significant amount of water can condense on both sides of the ceiling. Liquid will penetrate into the pores building materials, and lead to the formation of fungus, destruction of the structure of the support beams on the roof of a cold attic, etc.

In room high humidity negatively affects the finishing of walls, ceilings and floors.

Types and materials

Vapor barrier is a common name various materials. Previously, people used fatty clay as such a product, which was not capable of allowing moisture to pass through. Today, many different modifications have appeared on the market. polymer materials(“Izospan”, etc.), which are much easier to install.

Film

This type vapor barrier materials are the most common and in demand.

This group includes the following types of products:

• Polyethylene film. A relatively inexpensive material that protects well from steam penetration. It can be used only at moderate temperatures, which will not lead to damage to the structure. Another disadvantage of polyethylene is its low strength. When laying, such a film can be easily torn without noticing even minor damage.
• Polypropylene film. The material can withstand temperature changes much better than polyethylene-based products. It easily resists ultraviolet radiation, which increases its service life several times.

Today, manufacturers also add viscose and cellulose to the composition of films. The resulting material is able to retain a significant amount of moisture. Experts recommend using this film only in places where there is ventilation through which water can evaporate.

• Membranes. They appeared on the market relatively recently and have already become widespread. The material is capable of transmitting moisture well only in one direction. Therefore, when laying, it is important to consider the location of the layer relative to the pores.

Foil

Rolled vapor barrier is not intended for use in high temperatures. It is used mainly in the construction of private residential buildings. But if you decide to insulate the ceiling of the bathhouse, then you should use foil products. Outwardly, they resemble films, but one side is covered thin layer foil. This structure allows not only to retain steam, but also to qualitatively reflect thermal radiation.

Depending on the structure, foil films can be divided into the following types:

• Foil on kraft paper. One of the cheapest products. Although the material is easy to install, it is damaged by fungus over time. Another disadvantage can be considered its hygroscopicity.
• Lavsan compositions on kraft paper. Manufacturers claim that the substance can withstand temperatures up to +140 degrees. But many users claim that in reality these materials do not behave well in such conditions. Moreover, such coatings are easily damaged by any chemical mixtures. Therefore, it is not advisable to use it in a bathhouse. detergents and other aggressive compounds.
• Foil applied to fiberglass. The highest quality vapor barrier, distinguished high strength and high-quality thermal insulation indicators. The only downside is the high price, which is not affordable for everyone.

Which one to choose?

Vapor barriers are often used only in conjunction with insulation materials (glass wool, etc.).

When choosing such a product, several factors should be taken into account:

• Environment of use. If this is an ordinary residential building, then the best option membranes or reinforced polypropylene film will become. They pass steam well in only one direction. To insulate the ceiling in a bathhouse, only foil materials should be used.
• Manufacturer. The most popular brands of vapor barrier for roofing are Izospan and Yutafol NAL. Here you can find both film and foil products that meet all standards.
• Laying technology. Sometimes it is difficult to perform a vapor barrier on the attic floor, since the materials will be subject to serious loads. For such purposes, it is better to use durable membranes.

The quality of ceiling protection depends on the approach to installation of vapor barrier materials.

To avoid any damage and possible shortcomings, you should follow a few simple rules:

• It is advisable to fasten polyethylene or polypropylene film only with staples or small nails. Experts recommend placing thin material under the fasteners. wooden plank. It will not only reduce the risk of damage to the material, but will also better press it to the frame.
• Regardless of the vapor barrier used, all elements must be joined with an overlap of at least 15 cm. The joints must be glued together with wide tape, which can be found in a specialized store. If a foil-based vapor barrier is used, then it must be secured with foil tape.

• It is not advisable to stretch the film too much when laying it. It must be loose so that it has room to expand or contract when heated or cooled. This will prevent the formation of cracks or tears.
• If the film is spread over protruding wooden beams, then it is desirable that it follows the relief as accurately as possible. To do this, it must be fixed in the corners with additional fasteners.

Vapor barrier is a unique opportunity to protect thermal insulation from moisture, which, in turn, will make your home warm and cozy.

Owners of private houses very often observe the formation of condensation on the ceiling covering. The reason for this is the cold attic. The simplest and most effective solution to this problem is the installation of a vapor barrier.

Peculiarities

The construction of almost any house involves the construction of attic spaces of various types. The simplest are cold attics, which are unable to maintain the temperature at the same level.

This design consists of several main parts:

• Roofing covering. In most cases, there is no insulation here, and only the finishing material itself is used to protect against rain.
• Exterior walls.
• Overlap. A warm attic can be supplemented with a layer of insulation.

What is it for?

Vapor barrier is a special material that is not capable of allowing moisture to pass through. These products are designed to protect insulation, as well as internal surfaces in the house from possible moisture penetration.

If this material is not used, a significant amount of water may condense on both sides of the ceiling. The liquid will penetrate into the pores of building materials and lead to the formation of fungus, destruction of the structure of the support beams on the roof of a cold attic, etc.

Indoors, high humidity negatively affects the finishing of walls, ceilings and floors.

Types and materials

Vapor barrier is a general name for various materials. Previously, people used fatty clay as such a product, which was not capable of allowing moisture to pass through. Today, many different modifications of polymer materials (Izospan, etc.) have appeared on the market, which are much easier to install.

This type of vapor barrier materials is the most common and in demand.

This group includes the following types of products:

• Polyethylene film. A relatively inexpensive material that protects well from steam penetration. It can be used only at moderate temperatures, which will not lead to damage to the structure. Another disadvantage of polyethylene is its low strength. When laying, such a film can be easily torn without noticing even minor damage.
• Polypropylene film. The material can withstand temperature changes much better than polyethylene-based products. It easily resists ultraviolet radiation, which increases its service life several times.

Today, manufacturers also add viscose and cellulose to the composition of films. The resulting material is able to retain a significant amount of moisture. Experts recommend using this film only in places where there is ventilation through which water can evaporate.

• Membranes. They appeared on the market relatively recently and have already become widespread. The material is capable of transmitting moisture well only in one direction. Therefore, when laying, it is important to consider the location of the layer relative to the pores.

Ceiling vapor barrier in a cold attic: types of materials and recommendations for use
Why do you need a ceiling vapor barrier in a cold attic? What materials are used for vapor barrier? Which is better to choose? Tips and recommendations for installation. What are the advantages of foil material?

If an apartment or private house has an unheated and, accordingly, cold room above the ceiling, homeowners may encounter an unpleasant problem - the formation of condensation on ceiling surface. To avoid this disaster, in a cold attic, a vapor barrier on the ceiling is essential. What it is and how it can solve the problem will be discussed in this article.

What is it and why

Vapor barrier is a specially laid material that does not allow moisture to penetrate into the structure protected from it. To put it simply, it is a thin film through which water cannot penetrate. In a situation with a ceiling, it does not allow warm humid air, rising up, leave the room. To create a vapor barrier layer in different situations You can use different materials:

• Plastic film or glassine
• Special films with membrane effect
• Liquid mastics and varnishes designed to create a vapor barrier layer
• Foil types of insulation

Some of them simply create an impenetrable barrier and prevent water from entering the insulating layer or settling on a cold surface concrete floors. Other vapor barriers are capable of allowing some air to pass through, but retain moisture. Films with a layer of foil applied prevent moist air masses from passing through them and have another function - they reflect some of the heat back into the room.

Polyethylene and glassine

These insulating agents create a barrier that is impermeable to moisture. However, they not only prevent water from getting into the insulating layer or getting on cold floor structures, but also prevent air circulation. Therefore, in a room with polyethylene or glassine as insulation from moisture on the ceiling, it is necessary to install a ventilation system to ensure normal air exchange.

There are not too many advantages of such insulators, but to be precise, there is only one thing - price. Both polyethylene and glassine are very inexpensive. At the same time, polyethylene lasts quite a long time, while glassine is characterized by fragility and rapid wear.

This - special materials with limited breathability. They allow air to pass through, but retain moisture. The most common and popular vapor barrier of the Izospan brand has characteristic feature– a fleecy surface on which tiny drops of condensate accumulate and evaporate quite quickly.

The cost of such materials will be higher than that of polyethylene with glassine, but the efficiency of moisture removal is much higher, and air exchange remains within the normal range. At the same time, there are certain features of the installation of such membranes - to remove moist air vapors, a ventilation gap is necessary. Therefore, installation decorative covering the ceiling from the side of the room is made on a lath or frame, which will create the necessary space for ventilation.

Liquid coatings

A fairly new solution, created thanks to the achievements of chemists. Looks like regular varnish or mastic. It is applied to the surface in the same way as conventional paints. After drying, a special coating is formed that can allow air to pass through, but prevent the passage of water vapor. Such materials are often used to vaporize the ceiling on the cold attic side.

In addition, this will be a very effective solution if processing is carried out flat roof in buildings without an attic. In this case, a suitable insulation is laid on top of the applied insulation and the entire structure is waterproofed. In some cases, similar materials may be harmful to health and should only be used in non-residential premises. Be sure to familiarize yourself with the characteristics of the selected paintwork material.

Ceiling vapor barrier in a cold attic
Vapor barrier in wooden buildings vital. She will provide long term insulation materials services and load-bearing structures ceilings In cases with concrete floors, a layer of film can prevent condensation.

Correct vapor barrier the attic ceiling on wooden beams allows you to cut off water vapor from the interior of the building from the insulation. If this ceiling uses insulation type basalt wool, which, when wet, greatly loses its heat-insulating properties, then properly performed vapor barrier of the attic floor on wooden beams will allow you to save a lot on heating.

What do you need to know before starting film installation work? Firstly, there are different types of vapor barriers. Indoors, you can use ordinary thick polyethylene films, which will cope with this work no worse than expensive specialized materials.

Secondly, if you use specialized films, you need to lay them correctly. Usually the vapor barrier is laid with the rough side facing the room, and smooth side to the insulation. This allows condensed moisture to evaporate from the rough side.

Next, the joints of the vapor barrier must be glued. For this purpose, vapor barrier tape is used, which prevents the penetration of steam through leaks in the joints. You cannot use regular tape, as over time it will come away from the film and all the work will be wasted.

The vapor barrier is secured with paper clips using construction stapler. If you are not using a specialized film, but a regular one, you need to use spacers for paper clips. These can be pieces of polyethylene folded 2 or 4 times.

The paper clips on top are also sealed with special tape for vapor barrier. Next, a base for finishing can be applied to the film from the side of the room, or a lath for a suspended ceiling can be mounted.

When installing the sheathing or applying the base, do not damage the film. It is better to first use the sheathing and rough ceiling, and only then attach the finishing shelf to it, which will carry the final finish.

See more on this topic on our website:

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Can film be used as a vapor barrier?
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Vapor barrier - which side should be laid to the insulation
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Paul in wooden house- waterproofing and vapor barrier
The most ordinary non-insulated floor in a wooden house, the hydro and vapor barrier of which is done according to the rules, will last a long time. Wood that, in this case, is not affected by moisture.

How to work independently wooden block House
Houses made of wood are buildings that are distinguished by their reliability, aesthetics and environmental friendliness. Despite the simplicity and naturalness of the material, structures made from it are quite expensive and affordable.

Correct vapor barrier of the attic floor using wooden beams
Correct vapor barrier of the attic floor using wooden beams will keep the ceiling insulation intact and will not allow moisture to reduce its thermal resistance. See diagrams on our website.

Ceiling vapor barrier last floor- mandatory part complex works for insulating the ceiling of a cold attic. For concrete foundations It is enough to seal the seams hermetically, lay a continuous layer of vapor-proof film on top of the slabs, then insulation and waterproofing membrane. Vapor barrier and insulation wooden floor they do it differently.

Why do you need a vapor barrier?

• protect the insulation from moisture vapor entering it along with warm air from the heated room,
• prevent the creation of conditions for structural materials to get wet,
• protect living spaces from mineral wool particles entering them.

And if the last point is aimed at ensuring comfortable conditions for humans and is a consequence of the properties of the material, then the first two are mandatory according to current standards.

The entire structure of the “pie” of the insulated ceiling of a cold attic must meet the requirements of SP 23-101-2004, which regulate the design standards for thermal protection.

According to clause 8.5 general provisions technical solutions must provide reliable waterproofing thermal insulation materials and limit the penetration of water vapor into them as much as possible. A mutual arrangement layers should exclude prerequisites for the accumulation of moisture and create conditions for its weathering.

Installation rules

Wooden ceilings are beams filled with boards or panels of the rough ceiling on the side of the room. This device determines the specificity of the order of layers. If on a concrete floor the vapor barrier is laid on a slab under the insulation (the same as when insulating a flat roof), then in this case it should still protect wooden elements designs.

The sequence of layers and installation of vapor barrier will be as follows:

1. They arrange the ceiling - a rough ceiling is attached to the beams (number 8 in the diagram).
2. On the side of the room, the false ceiling is covered with a vapor barrier film (number 9 in the diagram). If it is a reinforced vapor barrier (with a two- or three-layer structure) or heat-reflecting vapor barrier, then the anti-condensation rough surface or metallized layer should face the inside of the room.
3. The overlap between the panels, regardless of the direction of laying, is 15 - 20 cm.
4. The edges of the vapor barrier layer along the perimeter are brought out onto the walls and fixed to them.
5. The joints of the canvases and the perimeter are taped with vapor-proof tape.
6. Between materials with an anti-condensation or reflective surface and finishing a ceiling gap is required. It is provided by stuffing the slats with a thickness of 4–5 cm.

Insulation of the ceiling of a cold attic is carried out as follows:

Between the beams, mineral wool (in soft mats or in rolls) is laid on the surface of the false ceiling. The insulation layer is calculated so that the total reduced heat transfer resistance of the entire floor structure is not less than the standard value.

In accordance with the requirements of clause 8.20 of SP 23-101-2004, waterproofing of insulation is required along the perimeter of a cold attic for a width of 1 m or more. In private houses, with a relatively small building area, the procedure is simple - a waterproofing membrane with a high vapor permeability (superdiffusion) capacity is laid over the entire surface of the heat-insulating layer. The vapor permeability of waterproofing is needed to ventilate excess moisture from the insulation when the temperature and humidity level of the atmospheric air changes.

The membrane is laid without tension close to the thermal insulation with the white side. Attached to floor beams and around the perimeter. The overlap between the panels is 15 – 20 cm.

Counter slats 4–5 cm thick are placed on the beams (number 3 in the diagram), which are ensured by the ventilation mode of the heat-insulating layer.

The floor is laid along the counter slats.

What you need to know to prevent dripping from the ceiling

Insulation of an unheated attic can only be carried out if it is ventilated (clause 8.19 of SP 23-101-2004).

• At the solid pitched roof ventilation openings must be at least 0.1% of the floor area.
• U pitched roof from piece roofing materials you can do without ventilation holes- there are enough gaps between the roof elements.

You can turn on the heating only after the insulation of the floor and the vapor barrier of the ceiling have been completed in full.

How to make a vapor barrier for a cold attic ceiling
Ceiling vapor barrier technology for insulating the ceiling of a cold attic. The order of laying layers and features of installation of vapor barrier materials on wooden floors.

In order to reduce heat loss through building structures, they are equipped with a layer of thermal insulation. Almost all types of insulation require protection from penetration atmospheric water outside and household fumes from inside.

The construction of a vapor barrier cannot be neglected, because this component of the insulation system plays no less a role than waterproofing.

It is especially important to know how a vapor barrier is constructed for a ceiling in a wooden floor, since materials that are extremely sensitive to excess water are used in its construction.

Building structures from the inside are constantly exposed to steam flows released during mandatory operations. household work, breathing of household members, hygiene procedures, etc.

The penetration of water suspended in the air into the systems that enclose and insulate a house negatively affects their technical and operational properties.

On surfaces moistened with steam, colonies of fungi settle at a brisk pace, rendering almost all types of building materials unusable with amazing speed.

Wooden elements rot and collapse. Wet insulation loses about half of its insulating qualities, because... The water contained in it significantly increases thermal conductivity.

Saturated with water suspended in it warm air always rushes to where the pressure and moisture content are lower. In our northern latitudes, for most of the year, the temperature and humidity parameters inside buildings are significantly higher than outside them. This feature explains the direction of movement of vapor-containing air masses moving from indoors to the external environment.

The predominant volume of evaporation according to its own physical nature is directed upward to “exit” into the atmosphere through the enclosing systems.

The most active air flows that include steam “attack” ceiling, the upper segment of the walls and roof structure. It is they who need to be strongly protected from the penetration of water in the air.

The process of air masses flowing into areas with lower pressure and water saturation is called diffusion. There is nothing particularly scary about it, if during construction building structures no mistakes were made. Humid air simply will not penetrate the thickness of the insulating pie or move outside without causing damage to the structure.

However, if there were violations during the construction of a house with insulation systems technological rules, water will begin to linger in the enclosing structures.

IN best case scenario the result will be increased heat loss, a feeling of eternal cold and dampness. In the worst case, destruction or damage to structures is coming, dictating mandatory major repairs.

Steam protection of attic floors

Function vapor barrier film in the thermal insulation cake is to prevent the penetration of water suspended in the air into building structures. This means that it is the vapor barrier that must stop evaporation, so as not to let it pass at all, or to reduce it to minimum values something that managed to get through it.

We have already found out that in our regions, steam, along with the air flow, most often moves from buildings to the outside. Only in summer heat Reverse current is possible.

The vapor barrier layer should be the first in the path of moist air. Consequently, it is laid on the side of the used premises before thermal insulation.

The installation of a vapor barrier along the ceiling is carried out if the attic is not intended to be heated. In this case attic space there is no point in insulating it at all, because... it will not be used at all or will be used as a cold warehouse.

It is true to protect the sheathing materials of the slopes and rafter frame still necessary. Waterproofing is installed against external influences, and a ventilation system is installed against the formation of condensation occurring due to the difference in temperatures inside and outside the structure.

According to the requirements of building regulations in winter period the temperature inside a cold attic should not exceed that outside by more than 5 - 6º C.

The rules outlined in SP 17.13330.2011 state that in order to equalize the temperature and humidity parameters inside and outside the attic, it is necessary to arrange natural type ventilation.

This means that it is necessary to provide the roof structure with vents, dormer windows, aerators, etc. The total area of ​​ventilation openings, regardless of their type and purpose, should be on average 1/300 of the floor area or horizontal projection of the roof. The described measure is quite sufficient to maintain the temperature and humidity balance specified by building regulations.

Specifics of the vapor barrier device

Materials with the lowest vapor permeability are used as vapor barrier protection for the attic floor. This characteristic indicates the ability to conduct evaporation in a certain volume per unit area, indicated in mg/m² per day. All building materials have it to a greater or lesser extent.

Despite the ability of wood to freely allow evaporation to pass through, excess exposure to moisture is undesirable. Natural organic matter is unstable in linear dimensions, when moistened it expands.

Naturally, this property is usually taken into account by designers, but excessive movement of elements wooden structures do not benefit them, and often lead to decay.

For normal operation ceiling located under a cold attic, it is necessary to correctly arrange the components according to their ability to pass humidified air.

The component with the minimum ability to conduct steam should be placed first, then with vapor permeability greater than the previous one.

Therefore, for a steam protection device, materials with the ability to transmit steam close to zero or equal to fractions of one are mainly selected.

Note that it can be several dozen, but must be less than that of thermal insulation. Even taking into account the fact that wood has a fairly high ability to conduct steam, the material for the device to protect against it should not allow more than a few tens of mg/m² of vapor to pass through per day.

The diagram of an insulated wooden floor, when viewed from the side of the premises being equipped, should look like this:

• Vapor barrier. A layer made of glassine, diffusion membrane, polypropylene or plastic film. During construction it is laid on top of the ceiling. When performing repairs, it is installed on the ceiling from the side of the rooms, glued or secured with slats.
• Thermal insulation. A layer made of backfill, roll or slab types of insulation. Most often it fills the space between floor beams, less often it is laid on top of the floor on a rough flooring or screed. If the attic is not intended to be used, then the thermal insulation is installed without waterproofing and wind protection.
• Waterproofing. A layer made of a diffusion membrane or perforated polyethylene. Installed only in the case of attic use, placed under the flooring or flooring.

If you do not plan to use the attic, then there is no need to install waterproofing on top of the insulating layer. It is transferred to the slopes, where it does the job of protecting the entire roofing system from atmospheric water.

The insulation layer over the ceiling also does not require wind protection, because The enclosing structure itself protects from heat blowing out of its thickness.

To service the roofing system, ladders are installed within the unused attic. They are laid directly on the joists if slab or roll material is used.

The drains are installed on legs if the insulation was formed by filling with expanded clay. Insulation materials laid loosely in the attic must be periodically “loosened” so that caking does not reduce the insulating properties.

Technological subtleties of laying a vapor barrier

The vapor barrier layer under the insulation is laid in the form of a pallet with peculiar sides extending onto the walls. Those. so that this barrier is not only between the ceiling and the thermal insulation, but also between the insulation and the parts of the walls in contact with it. Cover protective material obliged every beam or wall panel.

Laying of vapor barrier material on the ceiling is carried out:

• With a bend around each beam. The material “without interference” is laid in longitudinal strips perpendicular to the beams with a recess into the space between the beams. The opening of the vapor barrier is carried out taking this circumstance into account. If the length of one strip is not enough, the panels are glued together.
• With wrapping from the inside of each compartment of the box-panel floor. The material is cut into pieces corresponding to the size of the shield and the height of its walls.
• With laying on top of the rough flooring or with fastening with inside to the ceiling, if insulation is carried out in order to increase the insulating properties of the structure during the period of repair.

Regardless of the floor plan, the vapor barrier for the ceiling under the attic in a wooden house should form a continuous carpet that does not allow water to pass through or conducts it in a minimal amount.

For this cloth roll material laid with the overlap specified by the manufacturer, the size of which is indicated in the instructions, and glued together with one- or double-sided tape.

The vapor barrier material should be rolled out over the ceiling as it was wound by the manufacturer. There is no need to turn over or rewind anything. In order not to confuse the sides of the installation, the manufacturer designates the side in contact with the ceiling.

How to choose the right material

It is important not only to install the vapor barrier correctly, but also to choose the maximum suitable material for her device. Tandem vapor barrier - the insulation must work perfectly, preventing the possibility of the thermal insulation cake getting wet.

The most ancient version of the steam protection device is fatty clay, which was used to treat the ceiling from below or above.

Paired with clay, a dry soil-vegetative layer was used to prevent the penetration of hot air in hot weather and cold air in cold weather. Instead of soil, fine peat, shavings, sawdust, dry leaves and similar materials can be used.

Instead of outdated insulating varieties, materials specially designed to protect against steam and heat loss are now used. Their installation is much easier and significantly faster. However, in terms of insulating properties they are inferior to old proven methods.

For the installation of vapor barrier protection for attic floors, the following are now used:

• Glassine. A budget option with a vapor permeability of about 70 mg/m² per day. It is used mainly in domestic buildings that do not require an increase in humidity levels above standard values.
• Films made of polypropylene and polyethylene. Vapor permeability is measured in units, approximately 3 – 5 mg/m² per day. Most of these are reinforced materials that are resistant to temperature changes, mechanical stress and UV radiation. Suitable for arranging wooden floors under backfill insulation.
• Vapor barrier membranes with foil shell. Vapor permeability averages 0.04 – 2.55 mg/m². They are used for arranging rooms with high humidity and unstable temperature conditions: saunas, steam rooms, Russian baths, swimming pools, combined bathrooms.
• Anti-condensation diffusion membranes. Their ability to transmit steam varies over a wide range from 3 to 15 or several tens of mg/m². These are the newest varieties universal purpose. In a used attic floor, thermal insulation can be installed on the bottom and top sides.

Anti-condensation varieties are available as double-sided polymer membranes. On one side, which should be facing the steam, they are rough, which prevents the formation of dew. The opposite side is smooth, it prevents the penetration of moisture from the outside.

A vapor barrier constructed in accordance with technological requirements will eliminate premature wear and tear of building structures, eliminate costly heat leaks, and eliminate the possibility of dampness in a country house.

If an apartment or private house has an unheated and, accordingly, cold room above the ceiling, homeowners may encounter an unpleasant problem - the formation of condensation on the ceiling surface. To avoid this disaster, it is extremely necessary in a cold attic. What it is and how it can solve the problem will be discussed in this article.

What is it and why

Vapor barrier is a specially laid material that does not allow moisture to penetrate into the structure protected from it. To put it simply, it is a thin film through which water cannot penetrate. In a ceiling situation, it prevents warm, moist air rising from leaving the room. To create a vapor barrier layer in different situations, you can use different materials:

• Plastic film or glassine
• Special films with membrane effect
• Liquid mastics and varnishes designed to create a vapor barrier layer
• Foil types of insulation

Some of them simply create an impenetrable barrier and prevent water from entering the insulating layer or settling on the cold surface of concrete floors. Other vapor barriers are capable of allowing some air to pass through, but retain moisture. Films with a layer of foil applied prevent moist air masses from passing through them and have another function - they reflect some of the heat back into the room.

Polyethylene and glassine

These insulating agents create a barrier that is impermeable to moisture. However, they not only prevent water from getting into the insulating layer or getting on cold floor structures, but also prevent air circulation. Therefore, in a room with polyethylene or glassine as insulation from moisture on the ceiling, it is necessary to install a ventilation system to ensure normal air exchange.

There are not too many advantages of such insulators, but to be precise, there is only one thing - price. Both polyethylene and glassine are very inexpensive. At the same time, polyethylene lasts quite a long time, while glassine is characterized by fragility and rapid wear.

Membranes

These are special materials with limited breathability. They allow air to pass through, but retain moisture. The most common and popular vapor barrier of the Izospan brand has a characteristic feature - a fleecy surface on which tiny drops of condensate accumulate, which evaporate quite quickly.

The cost of such materials will be higher than that of polyethylene with glassine, but the efficiency of moisture removal is much higher, and air exchange remains within the normal range. At the same time, there are certain features of the installation of such membranes - to remove moist air vapors, a ventilation gap is necessary. Therefore, installation of the decorative ceiling covering from the side of the room is carried out on a sheathing or frame, which will create the necessary space for ventilation.

Liquid coatings

A fairly new solution, created thanks to the achievements of chemists. Looks like regular varnish or mastic. It is applied to the surface in the same way as conventional paints. After drying, a special coating is formed that can allow air to pass through, but prevent the passage of water vapor. Such materials are often used to vaporize the ceiling on the cold attic side.

In addition, this will be a very effective solution if flat roofs are treated in buildings that do not have an attic. In this case, a suitable insulation is laid on top of the applied insulation and the entire structure is waterproofed. In some cases, such materials may be harmful to health and can only be used in non-residential premises. Be sure to familiarize yourself with the characteristics of the selected paintwork material.

The attic is the technical area that completes the building. The attic is a technical room, it is rarely used as a living space; equipment necessary to ensure the life of the house can be placed here, and utility networks can be laid. The temperature difference in the residential area and the technical area should be no more than 3°-4°. Therefore, the technical room requires insulation.

Attic design with ceiling

Construction of an attic, which certainly expands living space, is much more expensive and requires certain knowledge, time and labor. The installation of a cold attic floor is many times cheaper and simpler.

The installation of an attic floor on wooden beams is a layer cake:

• plank board or roll;
• vapor barrier;
• ventilation gap;
• insulation;
• ventilation gap;
• vapor barrier;

Ventilation is carried out through gables or roof slopes. They also do dormer windows, placing them on opposite slopes so that air penetrates into all corners of the room.

Dormer windows are a difficult element to install, but useful. They may have different shapes triangular, oval, they are placed at a height of 1 meter from the floor, equipped with grilles and blinds. Through them it is convenient to go onto the roof for inspection, maintenance, checking the chimney, antenna and other things.

Beams for the attic

The attic floor is made using wooden beams after the installation of load-bearing elements is completed. This is the simplest and the best way for proper arrangement of the technical area.

The attic floor structure is usually made of wooden beams. These load-bearing elements have a number of advantages:

• maximum coverage 4.5 m between supports;
• light weight, load on the building, savings on the foundation;
• ease of installation, without the use of lifting equipment or a crane;
• availability of wood as an inexpensive material;
• speed of work, the ability to install an attic floor in a day or two;
• possibility of using any soundproofing materials.

For the manufacture of beams they use conifers wood resistant to moisture, rot, and fungus. The cross-section of the beams for the attic floor must correspond to the load, climatic conditions, thickness heat-insulating material. Beam dimensions of 150x200 mm are used if a serious load is expected on the attic floor. For example, it is planned to install a water tank and a transformer. For minimal load, beams of 100x150 mm are used.

The desire to save money and install 50x100 mm beams is not approved. An extremely important element of the house is the attic floor, which provides thermal insulation, sound insulation and reliability of the ceiling. The quality of the overlap guarantees savings in heat and heating costs.

You can calculate the number of wooden beams for the attic floor as follows. Divide the length of the room by 60-100cm (the distance between the beams), add 2 pieces to the resulting value, which will be laid on the walls. Beams should be laid on load-bearing and external walls.

Installation of wooden attic beams

The installation of an attic floor is carried out in several stages, each of which determines the quality and reliability of the structure. The work algorithm looks like this:

1. Preparation. The required length is cut, the wood is treated with a special compound that protects it from rotting, swelling and other troubles, the edges of the beam are wrapped with roofing felt, then the finished element is lifted up.

2. Laying in two ways:

• without protrusion beyond the external walls;
• with outlet beyond the outer walls.

It is necessary to lay it along the length at the required distance in relation to other structural elements; for any installation method, the following is taken into account:

• the maximum span width should not exceed 4.5 meters;
• the timber is laid on the ends of the walls; in some cases, a mauerlat is used - this is a thick beam secured with thick nails or steel studs into the walls around the perimeter;
• roofing material is laid under each beam layer to ensure waterproofing;
• the pitch of wooden beams is selected based on the size of the thermal insulation material.

3. The attic floor on wooden beams is carried out taking into account the construction of the ramp, which is a covering made of boards and slabs. Waterproofing, vapor barrier, and insulation are laid between the upper and lower eaves. The lower flooring is made on supports to which boards are attached, but it is better to use slabs or sheets of plywood 15-20mm thick. Fastenings are carried out with self-tapping screws in increments of 10-15mm so that the heat-insulating materials are securely held.

In order to mount the most robust construction you need to fill the bottom of each beam wooden blocks 50x50mm, they form a ledge on which boards or sheets are placed. You also need to secure the roll to the bars with self-tapping screws. The advantages of this design are exceptional reliability; the disadvantages will appear in the finishing of the ceilings, on which these bars will have to be sealed and hidden. Such a structure should be installed if you plan to actively use the attic.

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4. The final stage of installing an attic floor on wooden beams is the installation of the floor, for which boards are sewn on top to act as a subfloor. For the finished floor, a tightly laid tongue and groove board is used.

The subfloor is mounted on the same bars, on top. But before we start last stage should do:

• laying membrane-type vapor barrier;
• thermal insulation;
• another layer of membrane fabric.

The finished design is important element covering the roof and the entire building.

The importance of vapor barrier and methods of its installation

Vapor barrier of the attic floor ensures the safety of the wooden floor. It extends the life of the roof and helps create optimal microclimate in residential areas, taking away excess moisture and preventing heat loss. You should choose the material for vapor barrier carefully, without any intention of saving money.

Vapor barrier material has different side structures. On one side, the rough surface absorbs moisture, the other side with a film prevents moisture from penetrating into the heat-insulating layer.

The vapor barrier is installed, as is already clear, between the ceiling and the insulation in attic floors. Materials used:

• polyethylene;
• polypropylene.

Fabrics reinforced with a special mesh may have perforations. You can also use non-perforated film, leaving gaps during installation. The reinforced film has a metallized surface. The film is spread downwards with the metallized surface to reflect heat loss.

A layer consisting of fibers absorbs moisture, then evaporates it naturally. The materials are durable and resistant to ultraviolet rays.

There are also other vapor barrier materials that can be used when equipping the attic floor with wooden beams as a vapor barrier. These are varnishes and mastics, asphalt, bitumen, bitumen-kukersol. Today, such materials are rarely used, preferring non-woven fabrics of synthetic origin. These are so-called “breathable membranes”, capable of transmitting moisture and air, multi-layer, single-layer, equipped with aluminum foil.

The material is placed with a 20 cm overlap on the wall, secured with a stapler, the rough side down.