Cold attic. How to make a vapor barrier for the ceiling of a cold attic Laying a vapor barrier on the attic floor

Owners of private houses very often observe the formation of condensation on ceiling covering. The reason for this is 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. Warm attic can be supplemented with a layer of insulation.

What is it for?

Vapor barrier is special material, which is not capable of transmitting moisture. 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 of polymer materials (Izospan, etc.) have appeared on the market, which are much easier to install.

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

This group includes the following types of products:

Polyethylene film. Relatively inexpensive material, which 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 the 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 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.

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 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 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. Apply to the surface in the same way as regular 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, lay on top of the applied insulator suitable 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.

Ceiling vapor barrier in a cold attic
Vapor barrier in wooden buildings vital. It will ensure a long service life of insulating materials and load-bearing floor structures. In cases with concrete floors, a layer of film can prevent condensation.

Proper vapor barrier of the attic floor along wooden beams allows you to cut off water vapor from internal space buildings from 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. Typically, vapor barriers are laid with the rough side facing the room and the smooth side facing 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 fastened with paper clips using a 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 sheathing can be installed for suspended ceiling.

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:

Vapor barrier - which side to lay in a frame wall
Vapor barrier during the construction of a frame house is used to prevent moisture from entering the house into the thermal insulation materials located in the walls of the frame. One of the main conditions for using a heat insulator.

Can film be used as a vapor barrier?
Can a vapor barrier film be used when the budget is limited and the owner needs to save a little during construction? Yes, this option is possible. And for frame, etc.

Vapor barrier - which side should be laid to the insulation
When building a private house, the inevitable question is which side to lay the vapor barrier against the insulation so that the structural elements last for decades.

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.

Vapor barrier of the ceiling of the last floor is a 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 a waterproofing membrane. Vapor barrier and insulation of wooden floors are done 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 providing 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 ensure reliable waterproofing of thermal insulation materials and limit the penetration of water vapor into them as much as possible. And the relative arrangement of the layers should eliminate the 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:

They arrange the ceiling - a rough ceiling is attached to the beams (number 8 in the diagram).
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.
The overlap between the panels, regardless of the direction of laying, is 15 - 20 cm.
The edges of the vapor barrier layer along the perimeter are brought out onto the walls and fixed to them.
The joints of the canvases and the perimeter are taped with vapor-proof tape.
A gap is required between materials with an anti-condensation or reflective surface and the finishing of the ceiling. 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 homes, with relatively small area buildings, proceed simply - a waterproofing membrane with a high vapor permeability (superdiffusion) ability is laid over the entire surface of the heat-insulating layer. The vapor permeability of waterproofing is needed for weathering excess moisture from 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).

For a continuous 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 roofing 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.

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.

Film

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.

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, characterized by high strength and high-quality thermal insulation properties. The only negative should be considered high price, which is not available to 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 a thin wooden strip under the fasteners. 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.

Any processes that take place inside a house or living space affect the strength, durability and integrity of all layers of building structures. For example, due to the destructive effects of moisture, load-bearing wooden elements rot, and the effectiveness of thermal insulation decreases. To protect against moisture coming from the external environment and premises, vapor and waterproofing of building structures is carried out. We'll talk about insulating the ceiling surface. Moreover, protection from moisture is needed not only when there is a risk of flooding in an apartment building; vapor barrier of the ceiling in a cold attic in a private building is designed to protect structures and increase the efficiency of insulation.

Why is ceiling vapor barrier done?

The main purpose of the vapor barrier layer is protection against moisture condensing in building structures due to temperature changes. This is usually observed in a private house with unheated attic. But vapor barrier of the ceiling in a warm attic is also important, because it protects the insulation from the penetration of moist air from rooms with high humidity.

The second function of vapor barrier membranes is to ventilate the insulation. Compared to a dense waterproofing layer, vapor barrier allows air to circulate in building structures and remove moisture that condenses in the insulation. This protection is especially important when using wooden structures ceilings

Vapor barrier functions:

Protection of wooden floor elements from deformation, damage by rot and mold and subsequent destruction.
Vapor barrier extends the service life of building structures and insulation.
Vapor insulation is part of the insulation system for ceiling surfaces.
The fire safety of ceiling structures is increased.
If there is a living room above a room with humid processes, then the layer allows you to maintain a favorable microclimate in it.

There are several types of vapor barrier materials, differing in their characteristics and scope of use. What kind of vapor barrier on the attic ceiling will be used depends on the purpose of the room and the presence or absence of heating in the attic space.

Types of vapor barrier materials and areas of application

All vapor barriers according to their operating principle are divided into:

Standard materials that are attached to the inside of the ceiling.
Also on sale are insulators with a reflective layer that protect against the penetration of water vapor and prevent heat loss by reflecting heat into the room.
In buildings for seasonal purposes, vapor barriers with controlled action are used. When the steam cycle is unstable, it is important that the material allows it to escape through the pores in the surface. This insulating material laid above the insulation (closer to the top of the ceiling). Due to partial vapor permeability, the membrane does not allow moisture to remain in the insulation.
There are also insulators with variable vapor permeability. They are mounted above the insulation. Thanks to the special design of the pores, the material allows steam to effectively evaporate from the ceiling and insulation, but at the same time does not allow moisture condensing in an unheated attic to penetrate into building structures.

Also, all insulators are divided according to the type of material from which they are made. The ceiling vapor barrier scheme depends on the insulator used. Let's consider their features in detail.

Glassine

The material is made on the basis of thick cardboard and impregnated with bitumen. It is designed to protect building structures from moisture and water. It is attached to the ceiling on either side. The main advantage is considered low price, and the disadvantage is associated with a short service life.

Polypropylene films

The main advantage of polypropylene products is their high mechanical strength and resistance to sunlight. The use of these films is justified when the insulating layer is exposed to ultraviolet radiation for a long time. This usually happens when there is a significant break in construction during the summer.

Polyethylene films

The film copes well with its tasks when installed in the ceiling between an unheated attic and a bathroom or kitchen. This material has the highest coefficient of resistance to vapor permeation. If the bathroom or kitchen is located under an unheated attic, then it is better to choose a film with a reflective layer.

Advice! To extend service life film vapor barrier buy reinforced two-layer products. Even rodents cannot damage them.

Conventional membranes

Membranes can perform the functions of vapor and water insulators at the same time. Due to one-way permeability, membrane insulators allow steam to escape from the ceiling and prevent moisture from penetrating inside. The pores in the product have a certain configuration - they are narrow at the bottom and wide at the top. For the material to work effectively, it is important to install it right side– the narrow part of the pores is towards the insulation, and the wide part is towards the top of the ceiling.

Important! There are multilayer, single- and double-sided membranes on sale. They are equally effective, but double-sided products are more economical.

Breathable membranes

For efficient work With a regular membrane, it is important to lay it with a ventilation gap of 5 cm between it and the heat-insulating material. Because of this, the thickness of the overlap increases. Breathable membranes do not have this disadvantage. They are mounted close to the insulation. This is due to the peculiarities of their action - they allow water vapor from the heat insulator to pass out, preventing it from becoming damp.

In what cases is ceiling waterproofing used?

The main purpose of the waterproofing layer in the ceiling:

Waterproofing the ceiling against leaks from above is important in apartment buildings. It is done in the bathroom and toilet. Its purpose is not only to protect the room from flooding and damage to furniture, but also to prevent the appearance of mold on the ceiling.
The coating increases the service life of finishing materials and protects building structures from damage by water.
Waterproofing the ceiling in a private house is designed to protect electrical wiring from getting wet and short circuiting.

Waterproofing of the ceiling surface is carried out in rooms with high humidity (bathrooms, kitchens, toilets), in basements, on balconies and loggias, and ground floors. In a private house, this layer will protect living quarters in case of a leaking roof.

Waterproofing materials and applications

In apartment buildings, ceilings are often waterproofed from the inside. Materials different in composition, principle of application and action are suitable for these purposes. Each of them is intended for certain type surfaces and has its pros and cons. Most big choice among products designed to protect concrete surfaces from moisture.

Pasting materials

This insulator is divided into two types:

Polymer products are made on the basis of atactic polypropylene and modified copolymers. This includes polyethylene and vinyl plastic.
Non-polymer waterproofing materials - roofing felt, roofing felt, fiberglass.

Installation of this waterproofing on the ceiling is quite labor-intensive, so it is not advisable to use these materials. There are adhesive insulators with a self-adhesive base and materials that are fused to the surface using a gas burner. The only place where this option for moisture protection is appropriate is a loggia and a glazed balcony.

Penetrating insulation

Penetrating ceiling waterproofing is the most effective method of protecting the ceiling surface from moisture. The resulting coating is durable. The mixture is applied to a damp ceiling, which causes the active ingredients to transform into insoluble crystals. They tightly fill all the pores and cracks on the ceiling surface. Suitable for use on concrete ceilings only. It has been proven that these products increase the strength of structures by 15-20 percent.

Important! The main advantage of penetrating waterproofing is its harmlessness and the fact that it does not interfere with air exchange of the treated surface.

Coating waterproofing

These compositions are divided into several types:

bitumen-rubber (elastic);
bitumen-polymer (elastic);
cement-polymer (inelastic).

They are easy to apply and have a reasonable price. However, plaster must be applied above this waterproofing layer. The insulator is laid in several layers and is used to treat cracks, seams, floors, walls, ceilings in bathrooms, bathrooms, balconies or loggias.

Worth knowing! In terms of their composition, coating products can be two- and one-component. The latter are immediately ready for use, while the two-component ones require preliminary preparation.

Waterproofing by plastering

In addition to cement and sand, such plasters contain special additives and waterproof polymers. After hardening, they form a surface that protects against moisture penetration even under significant pressure. Waterproof plasters are suitable for treating brick and concrete surfaces. They are applied only to a dry base, without cracks.

Powder insulation

It is a mixture of resins, plasticizers and cement. A solution of plaster consistency is prepared by diluting it with water. After this, the mixture is simply applied to the ceiling surface. This material is rarely used due to its low resistance to mechanical stress.

Painting compositions

This includes special paints, varnishes, emulsions based on rubber, bitumen, latex and other waterproof components. These mixtures are easy to apply, environmentally friendly, economical consumption. Their main disadvantage is their short service life. Suitable for different surfaces, including wooden ones.

Water repellents

These are universal ready-made compositions, which are suitable for use on any surface. They have a water-repellent effect. Water repellents are divided according to the method of application. Some are applied by painting, while others are applied like plaster.

Vapor barrier of the attic floor of a cold attic protects wooden floor structures and insulation from steam entering them from the premises of the house. Steam condensing on beams can contribute to wood damage by fungi and mold, thereby reducing the service life of the structure. Condensing in the thickness of the insulation increases heat loss in the house, because water itself is good guide heat. In addition, water, freezing in the thickness of the insulation during the cold season, destroys the polymer bonds of the fibers and reduces the service life of the material.

Vapor barrier for a cold attic, when using foil materials, in addition to its main function, it allows you to reduce heat loss and, accordingly, heating costs due to the creation of a heat-reflecting screen.

Attic vapor barrier materials There are 2 main types on the market:

Film vapor barrier- does not allow steam to pass through (vapor barrier only).
Foil vapor barrier— does not allow steam to pass through and reflects thermal radiation (steam and heat insulation). This vapor barrier is installed with the foil side facing the premises.

Vapor barrier of attic floors with foil materials due to its characteristics, it is most preferable when building a reliable and heat-efficient house made of aerated concrete, brick or monolith.

Vapor barrier for the attic “pie”:

Attic floor (ladders) - necessary for maintenance, repair of the roof and attic space. In order to get into the attic, provide attic staircase with insulated hatch (Thermo). To exit from the attic to the roof, we recommend installing blind or glazed exit hatches (Velux, Vilpe, etc.) on the roof.
Para- or super-diffusion moisture-proof membrane - for effective removal of steam from insulation.
Insulation - mineral wool slabs. Recommended thickness for the Moscow and Leningrad region is 300mm. 200 mm are laid in the space between the beams, the remaining 100 mm are laid perpendicular to the laid layers - counter-insulation. For comparison - building codes in Finland, the thickness of the insulation is determined from 400 to 500 mm. It is recommended to delay the installation of insulation as much as possible - no earlier than 6 months after the completion of the construction of the house frame. Because For the construction of floors, timber is mainly used natural humidity. The timber must dry thoroughly, otherwise there is a high probability of damage to the wood by fungi and mold, which entails additional expenses for dismantling/installation work and treating wood with bleaches and antiseptics.
Counter grille and ventilated gap. For effective ventilation and removal of steam from the surface of the moisture-proof membrane.
Floor beams. As a rule, in private housing construction a 50x200mm board or 100x200mm natural moisture timber is used.
Lathing is the basis for laying insulation. It is recommended to use a 100x20 (25) mm board as lathing and lay it in increments of 70-80 mm. The resulting cracks will form an additional air thermal layer under the insulation. That. insulation slabs (mats) will not lie on vapor barrier film, but on a rigid base, under which there will be a vapor barrier. This solution eliminates the possibility of accidental damage to the vapor barrier or its pushing through when laying insulation, during maintenance and repair work roof and attic. With this, you can start interior decoration premises, and postpone installation of insulation as much as possible (see above).
Vapor barrier of attic floor on wooden beams- fastened with a construction stapler from below to rough ceiling(lathing), which allows you to cut off vapors from the entire floor structure. It is necessary to overlap the vapor barrier rolls by at least 15-20 cm and carefully glue them with aluminum adhesive tape. Be sure to form overlaps on the walls of 15-20cm and carefully glue them (place them under plaster and other wall finishing). Carefully seal the places where chimneys, ventilation pipes and other utilities pass through the attic floor using special hoses. The best material as a vapor barrier it is a high-density polyethylene film of 200 g/m² and above.
Closing attic - the finished ceiling is attached to the vapor barrier. The finished ceiling (OSB, gypsum board, etc.) is installed along the sheathing and guides. For the best fire protection, it is recommended to “sew up” the ceiling with 2 layers of plasterboard sheets.

Vapor barrier for cold attic floors (diagram):

Professional opinion: most effective attic floor insulation vapor barrier for the Moscow and Leningrad regions - this is attic insulation mineral slabs 300mm thick with foil vapor barrier.

When ensuring insulation of a private house and insulation of the roof along the rafters, one must not forget that Special attention should be given to a place like the attic.

Development of attic floor insulation with mineral wool

Warm air tends to rise to the top, and therefore temporarily unheated room heat can escape through the cold attic space. Therefore, the issue of insulating the attic must be resolved without delay.

1 Why do you need attic floor insulation?

Insulating a cold attic floor with stone or mineral wool is generally necessary in lightly used rooms that are properly equipped with special roof ventilation.

The attic, or rather its ceilings, serves as a kind of boundary between heat and cold. In such places, the attic floors are exposed to intense moisture due to the formation of condensation.

However, you can properly insulate the floors in the attic of a house with mineral wool with your own hands. The very process of insulating the floor in the attic with mineral wool is the creation of a durable thermal insulation coating, which will have a low degree of thermal conductivity.

The technology itself for insulating mineral wool floors in the attic, as well as Energoflex thermal insulation for pipes, implies strict adherence to its stages and requirements.

The technology itself is quite simple and understandable. Good thermal insulation Attic flooring using mineral wool helps close unwanted gaps.

To do this, the insulation must be laid tightly. In most cases, mineral wool is used to insulate the attic of a house.

The presented insulation is the most suitable for this type of work; it can also be used to insulate the floor surface in the living areas of the house.

Schematic insulation of the attic floor with mineral wool

By organizing good insulation with mineral wool, the most optimal temperature will be maintained in residential premises.

If the procedure is performed incorrectly, moisture rising from the floor of the house will lead to the formation of condensation.

It will accumulate on the ceiling and then seep through the ceilings. The resulting temperature difference in those areas where the attic floors adjoin the walls of the house initiates the formation of mold and microscopic fungi, which can be causative agents of allergic diseases.

1.1 Requirements for attic insulation

The process of insulating the attic floor and insulating the roof of a house with your own hands, or rather the level of its quality, has a direct impact not only on the size of heat loss, but also on the service life of the entire truss structure and roof covering.

The fact is that water vapor located inside the heated room diffuses to the attic of the house. In order for the insulation used to provide a high degree of calculated efficiency of the thermal insulation layer, it must always be dry.

Based on this, the insulation must be protected from excessive humidification by vapors of rising heated air using a special vapor-proof material.

If the attic space is well insulated, it will not only provide high-quality thermal insulation, but will also help increase the service life of the entire roofing structure.

If there is no vapor barrier, steam will penetrate through the unprotected attic floors and condense on the floor surfaces.

This will lead to moisture flowing onto the rafters, which, under its influence, will begin to slowly rot from the inside.

As a result, the likelihood of destruction increases roofing pie. The thermal insulation performance of the structure is also reduced due to the fact that the tightness of the vapor barrier layer has been compromised.

Before insulating the attic, you need to drain the layer and remove moisture from the entire attic space. To do this, ventilation should be done through windows. They can be:

In order to ensure maximum ventilation intensity, the total area of all ventilation openings should be equal to 0.2-0.5% of the attic floors.

If all work is carried out correctly, then icicles will not form on the roof in winter. The process of insulating the attic space itself is carried out not from the living quarters, but from the attic floor.

This is the most convenient way to lay insulation, the choice of which depends on the technology used and design features buildings.

1.2 Features of insulation of beam floors

When implementing such an insulation scheme using mineral wool, heat is retained in the space between the beams. Their usual height is almost always enough for this, but if necessary, several bars are packed on top.

Insulating the ceiling with mineral wool from the attic side

The lower part of the ceiling is sewn up using molded material, as when insulating the attic of a private house. For this, lining or sheets of plasterboard can be used.

The subfloor covering is laid on top of the beams. This can be a tongue and groove board, plywood sheet or OSB board. Mineral wool is placed on a previously prepared special vapor barrier layer.

An alternative can be an ordinary film made using polyethylene. If the vapor barrier material is foil-coated, then it is laid with the shiny surface down.

The intermediate distance between the beams is filled with mineral wool with the required thickness parameters. The surface of the beams must be equipped with an additional insulating layer.

This will lead to blocking the so-called cold bridges and will significantly reduce the overall level of heat loss. If high quality timber was used to create the beams, then the finishing material is spread directly onto their surface.

Mineral wool is placed between them as when insulating a roof using polyurethane foam, and the attic floor is laid on top. The use of this technology is especially important in houses that are made of logs or beams.

It is important to reliably protect mineral wool from the smallest drops of moisture, this is especially true if the roof has minor coating defects that cause leaks.

The layer of mineral wool must be reliably protected from the effects of wind from the eaves. For this purpose, mineral wool slabs with a high degree of density are used.

2 Why is mineral wool used to insulate an attic?

In most cases, when insulating attic floors, the consumer's choice falls on mineral wool. Its advantage is that its installation does not require special skills.

Mineral wool has excellent thermal insulation properties. Its structure consists of thin glassy fibers, the length of which ranges from 2 to 60 millimeters.

Insulating the attic with mineral wool

High soundproofing characteristics are provided thanks to the presence large quantity air pores

These pores are located in the space between the fibers and can occupy 95% of the total volume of the insulation. Mineral wool is presented in three varieties; it can be basalt glass and stone.

Basalt wool is made using molten basalt rocks, to which binding elements are added.

This may be a carbonate type rock, which regulates the acidity level of the substance, which entails an increase in the service life of the insulation. Glass wool exhibits high heat-resistant properties and can withstand temperatures up to +450 degrees Celsius.

2.1 Technology for insulating attic floors with mineral wool

When carrying out work related to mineral wool, it is important to comply with all safety requirements and regulations.

This is due to the fact that in the process of cutting and laying such material, the air is filled with tiny particles that can enter the respiratory organs and thus cause harm to human health.

During installation, be sure to ensure the availability of personal protective equipment. Goggles, a respirator and thick rubber gloves must be available.

The process of insulating attic floors begins with the selection of the necessary tools and additional materials. You can't do without:

The essence of insulation technology is that the insulation must be carefully laid in the space between the attic floors or beams.

To enhance the thermal insulation qualities, reliable vapor barrier protection should be used. Warm and moisture-rich air will continuously rise from living rooms and get upstairs through the ceiling.

There, in the under-roof space, it will collide with a layer of insulation. Due to the fact that mineral wool is generally considered a vapor-proof material, it will absorb all the outgoing moisture inside itself.

If it is left without the necessary access to air and sunlight, it will gradually dry out and, ultimately, lose all its heat-insulating qualities.

Cold attic interfloor covering 20 cm min. wool

In order to avoid such destructive consequences, you need to lay it under a layer of mineral wool. vapor barrier material.

Before starting the main work, you will need to carefully calculate required quantity insulation.

The amount of cotton wool purchased depends on how many layers are planned to be used when covering the attic space. In addition, the thermal insulation thickness parameter directly depends on the climatic conditions in the region.

Insulating the ceiling of a cold attic with mineral wool

Insulating the ceiling of a cold attic with mineral wool - advantages. Features of insulation of cold attic floors with mineral wool.

Cold attic

The device of the so-called cold attic is used in significant amount pitched roofs private residential houses and baths. This is due to a number of advantages provided by such constructive solution. The main advantage is that, despite the presence of the word “cold” in the name, such an unheated attic can significantly reduce the heat loss of the building.

The installation of a cold attic is the simplest solution from a technological point of view, especially when compared with the alternative warm option or building an attic. The air temperature of such a room, as a rule, is slightly higher (no more than 4 degrees) than the air temperature outside.

The composition of the structure under consideration includes the following elements (from top to bottom):

roof covering;
external attic walls;
insulated ceiling between the attic and the living space underneath.

It should be noted that insulation of the ceiling of a cold attic with mineral wool or other heat-insulating material can be done both from above and below from the side of the living room, regardless of whether it is wooden or concrete.

The option under consideration has a number of advantages:

reliability of waterproofing of the coating. It is achieved by reducing the number of superstructures protruding above the roof, which, as a rule, are its weakest points;
ease of operation. The existing internal under-roof space makes it easy to inspect and maintain all floor and roof structures;
overlap area less area pitched roof, which reduces the area of possible heat loss;
availability of additional operational premises.

In order for the benefits of a cold attic design to be fully realized, it is necessary to correctly and competently resolve several issues related to the insulation of the attic floor, as well as proper ventilation of the cold attic.

Organization of ventilation

The main purpose of ventilation in this case is as follows:

removal of excess water vapor penetrating through the ceiling from below from the residential part of the building, in order to prevent the appearance of condensation and wetting of the insulation and rafter system roofs;
creating an optimal microclimate.
Ventilation occurs through two types of vents:
cornices (the air passing through them is called supply air);
ridge (exhaust air passes through them).

Their total area should be 0.2-0.33% of the roof covering area, in other words for a covering area of 1000 sq.m. The area of the vents should vary from 2 to 3.33 sq.m. This calculation is carried out in accordance with SNiP standards, and it is quite simple to do. He treats the same various options roofing pie covered with metal tiles, corrugated sheets or soft tiles.

The basic rule for the location of vents is as follows: the most efficient work ventilation system with the maximum distance between the inlet and outlet openings.

In most cases, a scheme is used with an approximately uniform arrangement of vents around the perimeter of the building under the overhangs and along the entire length of the roof ridge.

Additional ventilation is often performed through dormer windows installed on the gables or roof slopes, which help with enhanced ventilation. When installing them, they are guided by the rule of symmetry: in order to prevent the presence of unventilated areas, dormer windows should be located on opposite slopes.

Typically, dormer windows are made of three types:

They are installed in such a way that the lower part of the window is no more than 1 meter from the floor level, and the upper part is at least 1.75 meters higher from the floor level. Often, dormer windows are used as an exit to the roof for the purpose of inspecting the roof and the elements of the ventilation system and chimneys installed on it. Sometimes a special hatch is installed for this purpose.

In order to prevent birds from entering, the vents are equipped with protective nets or gratings, and blinds are installed on the dormer windows.

Thermal insulation options

The cold attic design can be used in buildings of any number of floors. One of mandatory conditions Its normal operation is high-quality insulation of the floor. It is performed in one of two ways:

from the attic side;
from the inside from the residential part of the building.

Thermal insulation from the attic

This option is considered the most effective. A wide variety of ceiling insulation for a cold attic can be used: mineral wool (the most commonly used option), polystyrene foam, expanded clay, etc.

Sequence of work stages:

vapor barrier device (ordinary PVC film or modern materials with much higher performance characteristics can act as a vapor barrier material);
laying mineral wool thermal insulation in two layers;
Creation protective coating from cement bonded particle boards.

This unit is one of many possible ones that fulfill the basic requirements for insulating the ceiling of a cold attic and allow you to obtain the following advantages:

due to the presence of a vapor barrier, moisture does not enter the insulation;
the DSP coating allows you to move freely without damaging the insulation;
the design is quite reliable and durable (to further increase the service life, it is recommended to treat the surface of the DSP with antiseptics, which significantly reduce the likelihood of fungi or mold appearing).

It is imperative to additionally insulate the perimeter of the attic. It is carried out by laying a layer of mineral wool 0.75-1 meter wide and 10 cm thick. This will reduce or completely avoid the risk of freezing in the premises top floor in the corners.

Thermal insulation from inside the living room

Installing a ceiling in a private house with a cold attic and insulation from the inside is done much less frequently, since the work is accompanied by a number of disadvantages:

the ceiling level decreases;
Carrying out thermal insulation work disrupts the finishing, if it has already been completed, and requires subsequent repairs;
not all thermal insulation materials are useful and environmentally friendly, which leads either to an increase in the cost of work or to a decrease in living comfort. For this reason, the use of mineral wool is not recommended. In addition, it is always recommended to leave a ventilation gap between the thermal insulation material and the finishing material.

Thermal insulation from the inside is often carried out in parallel with the installation of suspended ceilings.

One of the most common methods of insulation from the inside is the option using extruded polystyrene foam (penoplex):

First, the sheathing is installed, onto which the drywall will subsequently be attached. The thickness of the sheathing beam should be 2-3 mm greater than the thickness of the insulation, and the sheathing pitch should be 1-2 mm less than the width of the penoplex;
after this, the insulation is secured between the sheathing bars with additional fastening with dowels to the ceiling;
as finishing plasterboard or suspended ceiling is attached to the suspended ceiling.

There are many others possible ways thermal insulation of the ceiling, but despite all the differences in the technologies and materials used, the basic principles must correspond to those given above.

Conclusion

The installation of a cold attic, if the work is carried out competently and the technology requirements are met, is an effective and expedient design solution.

Insulation, ventilation and vapor barrier of the ceiling of a cold attic in a private house

How to properly insulate, ventilate and vapor barrier the ceiling of a cold attic in a private house and what is the best insulation to use?

Roof installation with a cold attic

Most pitched roofs in our country have a cold attic in their design. This name is due to the air temperature in the attic, which should not differ much from the air temperature outside the house. With this arrangement of the attic space, a sufficiently large buffer air zone is formed, which allows you to effectively regulate the temperature in the attic if it is properly arranged.

Cold attic design

When building the roof of a house, many people think about making a cold attic or attic underneath it? The easiest way to organize a roof is with a cold attic space. Construction of an attic will cost several times more and require more labor.. Although, it is undeniable that the attic will significantly expand the living space.

Cold attic roofs have the following main components in their pie::

roofing;
attic external walls (applicable for gable roofs with gables);
insulated ceiling between the living space and the attic.

Ventilation is provided by eaves and ridge vents. The air passing through the eaves openings is called supply air, and the air leaving through the ridge is called exhaust air. Additionally, ventilation can be done through dormer windows on the gables or roof slopes. The windows are equipped with louvered grilles to allow the ventilation intensity to be adjusted.

Dormer windows are located on opposite slopes of the roof so that there are no unventilated areas.

Dormer windows can be rectangular, triangular and semicircular in shape. Their lower part should be at a height of no more than 0.8-1.0 m from the floor of the attic, and the upper part should not be lower than 1.75 m from the floor in the attic. They can also serve as an exit to the roof of the house to inspect the roof, ventilation and chimney elements.

Steam and thermal insulation of a cold attic

For a roof with a cold attic, it is most important to minimize heat loss through the attic floor. For both wooden and reinforced concrete floors, a vapor barrier is mandatory. It is laid on the ceiling itself and protects the insulation from vapors that can condense in the heat insulator after passing through the ceiling of the living room. Slabs and slabs can be used as insulation bulk materials. The ceiling pie consists of a vapor barrier, floor beams and insulation.

The following types of heat insulators are often used in ceiling coverings::

expanded polystyrene and foam boards;
mineral wool slabs or mats;
expanded clay granules;
fuel or granulated slag;
sawdust with lime or clay;
pumice.

The thickness of the required insulation layer is selected depending on the estimated winter temperature using the table below.

Winter temperatures are calculated according to SNiP 2.01.01-82 (building climatology and geophysics) or selected by regions of the Russian Federation from the corresponding climate maps.

The insulation is laid between the joists or ceiling beams, and a boardwalk is made on top for the attic passages. Joists are usually 50 mm thick, and decking boards are 25-35 mm thick.

For ventilated attic spaces, soft or semi-solid heat-insulating materials are considered the most optimal.

Attic waterproofing device

Waterproofing roofs with a cold attic, according to many experts, is a controversial issue. Some say that waterproofing must be present under the roofing material, while others categorically recommend that it be abandoned. Here, a lot depends on the type of roofing material and the angle of inclination of the roof slopes.

Metal roofs are most susceptible to corrosion, which occurs due to possible small leaks or condensation. Therefore, we once again draw your attention to the fact that ventilation plays one of the main roles in the fight against condensation formed.

For flat metal roofs, experts recommend installing super diffusion membranes. It will prevent moisture from entering the outside of the roof when snow or rain blows in. No matter how well the roof is laid, there is always the possibility of minimal leaks. That is why, by paying a little extra, you will receive additional protection from moisture getting on the insulation in the ceiling of a cold attic.

Possible leaks or condensation entering hydrophobic insulation materials significantly reduce their thermal insulation properties.

If, for example, slate is used as a roofing material, then waterproofing can be abandoned. There is also corrugated sheeting with an anti-condensation coating on the market, which can hold up to 1 liter of water per 1 m2. For our part, we recommend always using waterproofing membranes, because this is the cheapest and easiest additional way to protect your roof from possible leaks.

When installing waterproofing membranes use a counter-lattice. It serves as a fixing strip and, due to its height, provides the necessary clearance for ventilation of the under-roof space. The installation of lathing in a cold attic is no different from insulated roofs. The dimensions of the sheathing and its pitch determine the type of roofing being installed.

Cold attic temperature

To prevent ice and icicles from forming on the roof, it is necessary to maintain the correct temperature and humidity conditions in the attic. If the thickness of the thermal insulation material is insufficient, significant heat losses through the ceiling. Warm air, heating the roof covering, causes snow to melt and ice dams to form. By choosing the right insulation layer, this can be avoided.

The effectiveness of a heat insulator can be assessed by measuring the temperature of the top layer of insulation. The electronic thermometer is immersed in insulation by 10-20 mm.

As you can see, the design of a cold attic pie is not particularly complex in design. The main task is to ensure the necessary intensity of ventilation and the thickness of the thermal insulation layer in the ceiling.

Cold attic: ceiling pie, device, ceiling vapor barrier and waterproofing

Construction and design of a cold attic pie. Vapor barrier for ceilings and waterproofing in a cold attic. Optimal temperature for the attic.

Vapor barrier for ceilings in wooden floors: technological rules for installation

In order to reduce heat loss through building structures, they are equipped with a layer of thermal insulation. Almost all types of insulation need to be protected from the penetration of atmospheric water from the outside and household fumes from the 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 for a ceiling is constructed in wooden floor, since during its construction materials that are extremely sensitive to excess water are used.

The role of vapor barrier in construction

Building structures from the inside are constantly affected by steam flows released during mandatory 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 containing pairs air masses moving from indoors to outdoors.

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” the 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 no mistakes were made during the construction of building structures. 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

The function of the vapor barrier film in a thermal insulation cake is to prevent water suspended in the air from penetrating into building structures. This means that it is the vapor barrier that must stop the evaporation in order to either not let through at all or reduce to minimum values what managed to pass 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, the temperature within 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 a natural type of ventilation.

This means that it is necessary to provide the roof structure with ventilation, 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 movements of the elements of wooden structures do not benefit them, and moreover, they often lead to rotting.

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 quite high ability conduct steam, the material for the protection device 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. Each beam or wall of the panels must be covered with protective material.

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

With a bend around each beam. The material is laid “without tension” longitudinal stripes 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 from the 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 most suitable material for its installation. 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. For the most part this is reinforced materials, resistant to temperature changes, mechanical stress and UV irradiation. 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. This newest varieties universal purpose. In exploitation attic floor can be installed on the bottom and top sides of the thermal insulation.

Anti-condensation varieties are available in the form of 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.

Vapor barrier for a ceiling in a wooden floor: vapor barrier in a wooden house

How to install a vapor barrier for a ceiling in a wooden ceiling, rules for choosing and using a vapor barrier film in the insulated structure of a wooden house.