Vapor barrier membrane for attic floors. Roof device with a cold attic. Preparation for the installation of vapor barrier on ceilings

When insulating a private house and insulating the roof along the rafters, one must not forget that special attention should be paid to such a place as 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 warming the attic must be solved without delay.

1 Why do you need insulation of the attic floor?

Insulation of the cold floor of the attic with stone or mineral wool, according to by and large it is necessary in little-used rooms that are properly equipped with special roof ventilation.

The attic, or rather its overlaps, perform the function of a kind of border between heat and cold. In such places, the attic floors are exposed to intense moisture due to the formation of condensation.

However, it is possible to properly insulate the floors in the attic of the 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 very technology of insulation with mineral wool in the attic floor, as well as thermal insulation Energoflex for pipes, implies strict adherence to its stages and requirements.

By itself, this technology is quite simple and straightforward. Good thermal insulation of the attic floor with mineral wool helps to close unwanted crevices.

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

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

Schematic insulation of the attic floor with mineral wool

With the organization of good insulation with mineral wool, the most optimal temperature will be maintained in the living quarters.

If the procedure is not performed correctly, 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 are adjacent to 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 insulation of the attic

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

The fact is that the water vapor 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 heat-insulating layer, it must always be dry.

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

If the attic space is well insulated, then it will provide not only high-quality thermal insulation, but also contribute to an increase in the operational life of the entire roofing structure.

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

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

As a result, the probability of destruction of everything increases. roofing cake... The thermal insulation performance of the structure also decreases due to the fact that the tightness of the vapor barrier layer has been broken.

Before insulating the attic, you need to drain the layer and remove moisture from the entire attic space. For this, ventilation should be carried out through the windows. They may be:

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

If all work is carried out correctly, then in winter period no icicles will form on the roof. The process of warming itself attic space is made not from the side of the living quarters, but from the attic floor.

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

1.2 Features of warming beams

When implementing such a thermal insulation scheme using mineral wool, heat is stored in the space between the beams. Their usual height is almost always sufficient for this, however, if necessary, several bars are stuffed on top.

Insulation of the ceiling with mineral wool from the attic side

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

On top of the beams, the sub-floor covering is laid. This can be a tongue-and-groove board, plywood sheet, or OSB board... Mineral wool is adjusted on a previously prepared special vapor barrier layer.

An alternative to it can be an ordinary film made with polyethylene. If the vapor barrier material is foiled, then it is laid with a 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 insulation layer.

This will lead to blocking of the so-called cold bridges and significantly reduce the overall level of heat loss. If a beam was applied to create beams High Quality, then the finishing material spreads directly to their surface.

Mineral wool is placed between them as when the roof is insulated 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 protect the mineral wool from the smallest drops of moisture with a high degree of reliability, this is especially true if the roof has minor defects in the coating, due to which leaks occur.

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

2 Why is mineral wool used to insulate the attic?

In most cases, when insulating attic floors, the consumer's choice falls on mineral wool. Its advantage lies in the fact that no special skills are required for its installation.

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

Insulation of the attic with mineral wool

High sound insulation characteristics are provided due to the presence of a large number of air pores.

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

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

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

2.1 Technology of insulation of 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 the smallest particles that can get into respiratory organs and thus harm human health.

When carrying out installation, be sure to take care of the availability of personal protective equipment. Goggles, a respirator and heavy rubber gloves should be available.

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

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

To enhance the thermal insulation qualities, a reliable vapor barrier should be used. Warm and moisture-saturated air will continuously rise from the living rooms and go up through the ceiling.

There, in the under-roof space, he will collide with a layer of insulation. In view of the fact that mineral wool is generally recognized as a vapor-proof material, it will take all the outgoing moisture inside itself.

If it is left without adequate air access and sun rays, it will gradually shrink and, in the end, will lose all its heat-insulating qualities.

Attic cold interfloor overlap 20 cm min cotton wool

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

Before starting the main work, it will be necessary to carefully calculate the required amount of insulation.

The amount of wool purchased depends on how many layers you plan to use when covering the attic. In addition, the parameter of the thickness of thermal insulation directly depends on the characteristics of the climatic conditions in the region.

Insulation of the ceiling of the cold attic with mineral wool

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

Source: uteplimvse.ru

Cold attic

The device of the so-called cold attic is used in a significant number of pitched roofs of private houses and baths. This is due to a number of advantages that are provided by such a 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 device of a cold attic is the simplest solution in terms of technology, especially when compared with an alternative warm option or the construction of an attic. The air temperature of such a room, as a rule, is slightly higher (no more than 4 degrees) than the same indicator of the outside air.

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

roof covering;
external attic walls;
insulated overlap between the attic and the living quarters under it.

It should be noted that the insulation of the ceiling of the cold attic with mineral wool or other thermal insulation material can be produced 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 coating. This is achieved by reducing the number of superstructures protruding above the roof, which, as a rule, are its weakest points;
ease of use. The available internal under-roof space allows you to easily inspect and maintain all floor and roof structures;
the overlapping area is less than the area pitched roof, the area of possible heat loss is correspondingly reduced;
the presence of an additional operated premises.

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

Ventilation organization

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

removal of excess water vapor penetrating through the floor from the bottom of the residential part of the building in order to prevent the appearance of condensation and moisture insulation and rafter system roofs;
creation optimal microclimate.
Ventilation occurs due to two types of vents:
eaves (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 coverage area, in other words for a coverage 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 the norms of SNiP, and it is quite simple to do it. It applies equally to different types of roofing cake coated with metal, corrugated board or soft tiles.

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

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

Often, additional ventilation is performed through roofs installed on gables or slopes. dormer windows, which assist in 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.

Usually, dormer windows are made of three types:

They are installed in such a way that Bottom part the window was at a distance of no more than 1 meter from the floor level, and the upper one was at least 1.75 meters higher from the floor level. Dormer windows are often used as an exit to the roof in order to inspect the roof and the elements of the ventilation system and chimneys installed on it. Sometimes a special hatch is installed for this.

In order to avoid the entry of birds, the air vents are supplied with protective nets or grilles, and blinds are installed on the dormer windows.

Thermal insulation options

The design of the cold attic can be used in buildings of any number of storeys. 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;
from the inside from the side of the residential part of the building.

Thermal insulation from the attic side

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

The sequence of stages of work:

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

This node is one of the many possible, fulfilling the basic requirements for insulation of the ceiling of a cold attic and allowing you to get the following advantages:

due to the presence of a vapor barrier, moisture does not enter the insulation;
DSP cover 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 fungus or mold).

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

Thermal insulation from the inside of the living room

The device of the ceiling in a private house with a cold attic and insulation from the inside is performed much less often, since the work is accompanied by a number of disadvantages:

the ceiling level goes down;
carrying out work on thermal insulation violates the finish, if it has already been completed, and requires its subsequent repair;
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 the comfort of living. For this reason, the use of mineral wool is not recommended. In addition, it is always advisable to leave a ventilation gap between the 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 (foam):

first, a crate is installed, on which drywall will subsequently be attached. In this case, the thickness of the lathing beam should be 2-3 mm more than the thickness of the insulation, and the step of the lathing should be 1-2 mm less than the width of the foam;
after that, the insulation is fixed between the lathing bars with additional fastening with dowels to the ceiling;
as finishing false ceiling drywall or stretch ceiling is attached.

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

Conclusion

The device of a cold attic with competent performance of work and compliance with the requirements of technology is an effective and expedient constructive solution.

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

How to properly make insulation, ventilation and vapor barrier for the ceiling of a cold attic in a private house and which insulation is better to use?

Source: www.hugebuilding.ru

Roof device with a cold attic

Most pitched roofs in our country have in their design cold attic... 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 makes it possible to effectively regulate the temperature in the attic if it is properly arranged.

Cold loft construction

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

Cold Attic Roofs have the following main ingredients in their pie:

roof covering;
attic exterior walls (applicable for gable roofs with gables);
insulated overlap between the living quarters and the attic.

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

Dormers are placed on opposite roof slopes so that there are no unventilated areas.

Dormers can be rectangular, triangular and semicircular. Their lower part should be at a height of no more than 0.8-1.0 m from the floor of the ceiling in 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 space, it is most important to minimize the heat loss through the attic floor as much as possible. For both wood and iron concrete slabs vapor barrier is mandatory. It fits on the floor itself and protects the insulation from vapors that can condense in the heat insulator, passing through the ceiling of the living space. Plate and bulk materials can be used as insulation. Ceiling pie consists of vapor barrier, floor beams and insulation.

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

expanded polystyrene and polystyrene plates;
mineral wool boards or mats;
expanded clay granules;
fuel or granular 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 temperature is calculated according to SNiP 2.01.01-82 (construction climatology and geophysics) or selected by regions of the Russian Federation from the corresponding climatic maps.

Insulation is laid between the lags or beams of the ceiling, and a boardwalk for attic passages is made on top. The logs are usually 50 mm thick, and the floorboards 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 necessarily be present under the roofing material, and someone strongly recommends abandoning it. Much depends on the type of roofing material and the angle of inclination of the roof slopes.

Metal roofs are most susceptible to corrosion 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 the formed condensation.

For gentle metal roofs experts recommend installing superdiffusion membranes. It will prevent moisture from entering the outside of the roof when blowing snow or rain. No matter how well the roof is laid, there is always the possibility of minimal leaks. That is why, by overpaying a little, you will receive additional protection against moisture ingress on the insulation in the ceiling of the cold attic.

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

If, for example, slate is used as a roofing material, then waterproofing can be abandoned. There is also a corrugated board with an anti-condensation coating on the market, which can hold up to 1 liter of water per 1 m 2. For our part, we recommend that you always use waterproofing membranes, because it is the cheapest and easiest additional way protect your roof from possible leaks.

When installing waterproofing membranes, a counter lattice is used. It performs the function of a fixing rail and, due to its height, provides the necessary clearance for ventilation of the under-roof space. The device for the lathing of a cold attic is no different from insulated roofs. The dimensions of the lathing and its pitch determine the type of roofing to be installed.

Temperature range of the cold attic

To prevent ice and icicles from forming on the roof, it is necessary to maintain the correct temperature and humidity regime in the attic. If the thickness of the insulating material is insufficient, significant heat losses occur through the floor. Warm air, heating the roofing, causes snow melting and ice formation. By choosing the right layer of insulation, this can be avoided.

You can evaluate the effectiveness of a heat insulator using the temperature measurement of the top layer of the insulation. Digital Thermometer immersed in insulation by 10-20 mm.

As you can see, the arrangement of the cold attic pie is not particularly complex. The main task is to provide the required ventilation intensity and the thickness of the heat-insulating layer in the ceiling slab.

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

The device and construction of the cold attic pie. Vapor barrier for ceiling slabs and waterproofing in a cold attic. Optimum temperature for the attic.

Source: vseokrovle.com

Vapor barrier for a ceiling in a wooden floor: technological rules for the device

In order to reduce heat loss through building structures, they are equipped with a layer of thermal insulation. Almost all types of insulation must be protected from the penetration of atmospheric water from the outside and household vapors from the inside. The vapor barrier should not 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 during its construction.

The role of vapor barrier in construction

However, if technological rules were violated during the construction of a house with insulation systems, water will linger in the enclosing structures. At best, the result will be increased heat loss, a feeling of eternal cold and dampness. In the worst case, destruction or damage of structures is coming, dictating the obligatory overhaul.

Steam protection of the attic floor

According to the prescriptions of building standards in winter, the temperature in the cold attic should not exceed it on the street by more than 5 - 6 ° C. type of ventilation.

Specificity of the vapor barrier device

Glassine

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

How is the vapor barrier of the ceiling in a wooden floor arranged, the rules for selection and use vapor barrier film in the insulated construction of a wooden house.

Source: krovgid.com

Insulation of the attic with mineral wool

Regardless of whether the attic is heated or not, it needs to be insulated. If this room is non-residential, then the insulation of the cold attic floor with mineral wool is carried out between the load-bearing floor beams. If the attic is provided heating system and people will live there, then the insulation is placed between the roof rafters. When choosing mineral wool, pay attention to the composition of the binder. It may contain phenol formaldehyde, which is a poison. It is better to take materials based on acrylic.

Thermal insulation of a cold attic with mineral wool

A vapor barrier is placed under the mineral wool.

To insulate the ceiling of a cold attic with mineral wool, you can take material of any density, from low to high. In this case, it is still preferable to dwell on lighter materials so as not to create additional loads on the beams. Some experts are inclined to believe that glass wool is better for insulating an attic with rock wool than stone wool. The latter is too fragile, and its weight is considerable.

As you already understood, the insulation of the cold attic of a private house with mineral wool is performed by laying thermal insulation between the load-bearing beams directly on the rough ceiling of the first floor. Due to the high hygroscopicity of mineral wool, it is necessary to use a vapor barrier film. In principle, even plain polyethylene can be used. Special loads on the film will not be and with careful installation, it will not tear. To be completely sure of the reliability of the protective layer, you need to use a polypropylene vapor barrier reinforced with fiberglass mesh.

Insulation of the attic with mineral wool, technology:

the bearing beams are sewn up from below - this is the rough ceiling of the first floor;
from the attic to rough coating vapor barrier is laid;
mineral wool is placed on top of the film.

The vapor barrier tapes should be overlapped, the joints are glued with double-sided tape. The minvata is placed by surprise so that there are no cold bridges in the places where the insulation is adjacent to the beams.

Thermal insulation of a cold attic with mineral wool is always preceded by a calculation of the thickness of thermal insulation. In any case, the layer will be at least 10 cm. Mineral wool is produced with a thickness of 5 cm. It is better to lay the thermal insulation in two layers with an offset of the joints. This will eliminate the possibility of heat loss through the joints of the mineral wool sheets.

After insulating the attic floor with mineral wool, you can immediately lay the floor over the beams. It is advisable to close the insulation with waterproofing before that - a material that does not allow water to pass through, while allowing steam to pass through, but only in one direction. It is important not to confuse which side to lay the waterproofing on, otherwise moisture will accumulate in the mineral wool, as a result of which the thermal conductivity of the material will increase significantly.

It is quite possible to use a fireplace for heating country house... For this, a heat exchanger is built in above the firebox.

Insulation of a heated attic with mineral wool

If the attic is heated and it belongs to the living area, then it is already an attic. Naturally, she also needs insulation. In this case, the thermal insulation does not fit between the floor beams, but between the roof rafters. In this case, there are two methods of how to insulate the attic with mineral wool.

Consider the first option - laying thermal insulation between the rafters from the ridge of the roof to the overlap of the first floor. In fig. 1, the area where the insulation is applied is marked in red. Remember that you need to insulate not only the attic, but also a small section of the overlap of the first floor, which is marked in green. As you can see, this option solves both problems at once. Installation technique (layers from the inside):

vapor barrier - attached with a stapler to the rafters. Fits with an overlap and taut. The joints are sealed;
mineral wool - put by surprise. You can use glass wool of any configuration (mats, slabs, rolls) or basalt wool in slabs with a soft end;
waterproofing - three-layer polypropylene diffusion membrane. The tapes are laid horizontally and overlapping, starting from the edge of the roof;
counter-lattice - the cross-section of the bars depends on the length of the roof slopes;
topcoat.

In terms of functionality, vertical tubular heating radiators are no different from horizontal ones.

In this article you will find information about plate heating radiators: characteristics, types, installation methods, operation and maintenance.

The second method of insulating an attic in a private house with mineral wool is somewhat different (see Fig. 2). The insulation is laid on the attic floor. Next, the wall is insulated according to the principle thermal insulation frame house ... Also, the insulation is laid on the overlap of the first floor from the attic wall to the end of the building. It is important that the insulation lays down without breaks, that is, from one surface it should go to another and preferably without joints. If there is a junction, then the thermal insulation must be tightly pressed against each other.

With such an installation, more material will undoubtedly go, but in the future there is its own benefit. You do not have to heat unused square meters for housing, so the cost of heating the house will be somewhat lower.

Today we figured out how to properly insulate the attic with mineral wool and came to the following conclusions. If the attic is unheated (cold), then the insulation is placed between the floor beams. If the attic is heated, then thermal insulation is placed between the roof rafters. There is a method of laying thermal insulation on the attic floor, then the wall itself is insulated and then a segment of the first floor overlap from the wall to the edge of the building. This approach will slightly reduce heating costs, since there is no need to heat extra square meters.

For work, it is better to use glass wool, since it does not break and, after squeezing, restores its previous shape. It is lightweight and does not overload the load-bearing floor beams and the rafter system. If you use stone wool, then you need to take plates with a soft end so that they can be inserted between the rails. A vapor barrier is laid between the heated room and the insulation. When installing thermal insulation on the roof, waterproofing is also needed, which is placed with outside... There must be a ventilated gap between the waterproofing and the finish.

How to properly insulate the overlap of a cold attic with mineral wool

On the overlap of a cold attic in a private house, mineral wool is laid between the beams. The heated attic is insulated in two ways, and each of them is correct.

Source: utepleniedoma.com

Vapor barrier is a practical solution to the problem of ceiling condensation in homes with a cold attic. The material prevents the penetration of moisture, protects the floors from the formation of condensation and further destruction, and also prevents the appearance of mold and mildew in the insulation plates.

Features of the device design

The cold attic includes a gable roof surface with roofing material and an insulated ceiling that separates the living space from the attic. To ensure ventilation, the attic is equipped with dormer windows, without which the air exchange in the attic will be disrupted, which will lead to the formation of condensation on the roof.

The floor of the attic is a ceiling, which simultaneously serves as the ceiling of the living room. When decreasing outdoor temperatures the overlap becomes susceptible to the appearance of condensation, the formation of which is due to the temperature difference between the lower and upper parts of it. In order for the condensate droplets that have appeared not to penetrate into the ceiling, it is covered from above with special materials that do not allow water to pass through.

In addition to protecting the base from moisture, the material performs an important thermal insulation function, preventing warm humid air from rising up. This technology significantly reduces the heat loss of the dwelling and allows you to significantly save on heating. Vapor barrier should be carried out on all types of substrates, including concrete and wooden floors. Isover slabs, glass wool or bulk materials can be used as a heater.

Types of materials

Before the advent of modern polymers, high-fat clay was used to seal the ceiling in a cold attic. Its disadvantage was a rather large weight and labor costs during installation. Today the construction market offers big choice vapor barrier, differing in the form of release, method of installation, properties and cost.

Film vapor barrier

Film vapor barrier is the most popular and demanded type, which is represented by polyethylene and polypropylene films and membranes:

The most widespread is polyethylene. This inexpensive and practical material reliably prevents steam penetration, but has restrictions on its use. It is recommended to use this type of film only in warm climates, subject to moderate temperatures: under the influence of extreme influences, it quickly loses its operational properties and collapses. The disadvantages include the low strength of polyethylene, which can lead to material ruptures even at the laying stage. Glassine, often used as a vapor barrier, is very similar in its properties to polyethylene: it also retains moisture well, but does not allow air to pass through at all.

More practical look vapor barrier is polypropylene... Such a film tolerates thermal surges well and is highly resistant to ultraviolet radiation. The service life of this material is several times higher than that of polyethylene. Modern technologies make it possible to produce films with the addition of viscose and cellulose. This significantly increases the strength and hygroscopicity of the material. A prerequisite for the use of such a vapor barrier should be the presence of good ventilation.

The water accumulated and retained by the pores of the material must evaporate freely, otherwise the properties of the material will be violated, which will lead to wetting of the floor.

The most modern and practical type of vapor barrier material is membranes. The isolant is designed in such a way that the ability to pass steam is possible only in one direction. Thanks to this property, moisture is quickly removed, as well as air exchange is carried out between the ceiling and the attic room. In the domestic construction market, the Izospan model is considered the most famous, the fleecy structure of which is able to hold condensate droplets and quickly evaporate them. The installation of a membrane covering involves the mandatory formation of a ventilation space, designed so that liquids have a place to evaporate.

Foil materials

This type is intended for operation at high temperatures and is used in the construction of baths as a vapor barrier for wooden floor beams. An insulator is a film coated on one side with a thin layer of foil. Thanks to this structure, the material is able to reflect heat radiation and retain steam well. There are several varieties of it:

The most budgetary option is foil kraft paper. The material fits well, but in the process of long-term use it is susceptible to the appearance of mold and mildew. The disadvantages include its low hygroscopic properties.

Lavsan coated kraft paper able to withstand temperatures up to 140 degrees. This allows it to be used as a vapor barrier material in the construction of baths. The disadvantages include low resistance to chemical compositions detergents.
Foil fiberglass is considered the highest quality vapor barrier, and is characterized by increased strength and long service life. The downside is the high cost of the material.

Liquid products

Liquid means for ensuring the vapor barrier of the ceiling are represented by varnishes and mastics. The compositions are applied to the floor surface and, after complete drying, form a thin film capable of retaining moisture and allowing air to pass through. This contributes to good ventilation of the floors and significantly reduces the likelihood of mold and mildew.

Some liquid products are only intended for use in non-residential premises and in contact with them can be harmful to health, therefore, when using them, personal protective measures should be observed

Compliance with simple installation rules and operating standards will help to significantly extend the service life of the vapor barrier.

Fasten the film material with staples or small nails, placing a thin wooden strip under the fasteners. This will allow the material to be better pressed against the substrate and will reduce the chance of accidental damage to the film.
The size of the overlap during the installation of any materials should not be less than 15 cm. The joints should be glued with a wide tape, and when installing foil materials, foil tape should be used.

Laying of vapor barrier materials should be carried out only with thermal insulation.
In the process of laying, it is recommended to carefully control the tension of the material: the film should be in a free position. This will avoid tearing the material when it is stretched and compressed under the influence of thermal changes.
To form the insulation of the ceiling of a residential building, it will be enough to use a membrane or reinforced polypropylene film, and during the construction of baths, only foil vapor barrier should be used.

Vapor barrier is one of the prerequisites for the construction of houses and baths with a cold attic.

Correctly selected material and competent installation will extend the service life of the ceiling, significantly reduce heat loss and make the stay in the room pleasant and comfortable.

Yet more information on the vapor barrier of the ceiling, see below.

If an apartment or a private house has an unheated and, accordingly, cold room above the ceiling, homeowners may face an unpleasant problem - the formation of condensation on the ceiling surface. To avoid this trouble, in a cold attic, a vapor barrier of the ceiling is extremely necessary. What it is and how it can solve the problem, we will consider 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 this. Simply put, this is a thin film through which water cannot penetrate. In a ceiling situation, it prevents the warm humid air rising upward from leaving the room. To create a vapor barrier in different situations different materials can be used:

Plastic wrap 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 able to pass part of the air through themselves, but retain moisture. Films with an applied layer of foil do not allow moist air masses to pass through themselves and have another function - they reflect some of the heat back into the room.

Polyethylene and glassine

These insulating agents create a moisture impermeable barrier. However, they not only prevent water from entering the insulating layer or fall 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 arrange a ventilation system for normal air exchange.

There are not too many advantages of such insulators, but if it is accurate, then there is only one thing - the price. Both polyethylene and glassine are very inexpensive. At the same time, polyethylene serves for a long time, and glassine is characterized by fragility and rapid wear.

Membranes

It - special materials with limited breathability. They let air through themselves, but retain moisture. The most common and popular Izospan brand vapor barrier has characteristic feature- a fleecy surface on which the smallest drops of condensate accumulate, evaporating rather 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 is a certain feature of the installation of such membranes - a ventilation gap is required to remove moist air vapors. Therefore, installation decorative coating the ceiling from the side of the room is made on a crate or frame, which will create the necessary space for ventilation.

Liquid paints and varnishes

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 for vapor barrier of the ceiling from the side of the cold attic.

In addition, it will be a very effective solution if a flat roof is being processed in buildings that do not have an attic. In this case, on top of the applied insulator, suitable insulation and the whole structure is waterproofed. In some cases, similar materials can 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.

The vapor barrier device should not be neglected, because this component of the insulation system plays no less 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 during its construction.

The role of vapor barrier in construction

Building structures from the inside are constantly affected by steam flows emitted during mandatory household work, household breathing, taking hygiene procedures, etc. Penetration of water suspended in the air into the systems enclosing and insulating the house has a negative effect on their technical and operational properties.

On surfaces moistened with steam, colonies of fungi settle at a brisk pace, making almost all types of building materials unusable at an amazing speed. Wooden elements rot and collapse. Wet insulation loses about half of its insulating qualities, because the water contained in it significantly increases the thermal conductivity.

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

The predominant volume of vapors, according to their own physical nature, is directed upward in order to "escape" into the atmosphere through the enclosing systems. The most active air currents involving steam "attack" the ceiling, the upper segment of the walls and the roof structure. They also need to be strongly protected from the penetration of water in the air.

The process of overflow of air masses into zones with lower pressure and water saturation is called diffusion. There is nothing particularly scary in it, if during the construction building structures no mistakes were made. Moist air simply will not pass into the thickness of the heat-insulating cake or move outside without harming the structure.

However, if technological rules were violated during the construction of a house with insulation systems, water will linger in the enclosing structures. At best, the result will be increased heat loss, a feeling of eternal cold and dampness. In the worst case, the destruction or damage of structures is coming, dictating the obligatory overhaul.

Steam protection of the attic floor

The function of the vapor barrier film in the thermal insulation cake is to prevent airborne water from entering building structures. This means that it is the vapor barrier that must stop the evaporation in order to either not let it through at all, or to reduce to the minimum values what has managed to pass through it.

We have already found out that in our regions, steam, together with the air flow, most often moves from buildings to the outside. Reverse current is possible only in summer heat. The first in the path of humid air should be a vapor barrier. Consequently, it is laid on the side of the operated premises in front of the thermal insulation.

The device of a vapor barrier on the ceiling is carried out if it is not supposed to heat the attic. In this case, it makes no sense to insulate the attic space at all, because it will not be used at all or will be used as a cold store.

It is true to protect the skate sheathing materials and rafter frame all the same it is necessary. From external influences, waterproofing is installed, from the formation of condensation that occurs due to the difference in temperatures inside and outside the structure, a ventilation system is arranged.

According to the prescriptions of building standards in winter, the temperature in the cold attic should not exceed it on the street by more than 5 - 6 ° C. type of ventilation.

This means that it is required to provide the roofing structure with air vents, dormers, 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 enough to maintain the temperature and humidity balance set by building codes.

Specificity of the vapor barrier device

Materials with the lowest vapor permeability are used as a vapor barrier 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 possess it to a greater or lesser extent.

Despite the ability of wood to freely pass vapors, excess exposure to moisture is undesirable. Natural organics are unstable in linear dimensions, when moistened, it expands. Naturally, this property is usually taken into account by the designers, but excessive movements of the elements of wooden structures do not benefit them, moreover, they often lead to decay.

For normal operation of the ceiling, located under a cold attic, it is necessary to correctly position the components according to their ability to pass humidified air. The first should be to place the component with a minimum ability to conduct steam, then with a vapor permeability greater than the previous one.

Therefore, for the steam protection device, materials with a steam permeability close to zero or equal to fractions of one are generally chosen. Note that it can be several tens, but must be less than that of thermal insulation. Even taking into account the fact that wood has a rather high ability to conduct steam, the material for the protection device against it should not allow more than a few tens of mg / m² of vapor per day to pass through.

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

Steam insulation. Layer made of glassine, diffusion membrane, polypropylene or polyethylene 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 fastened with slats.
Thermal insulation. A layer made of backfill, roll or plate types of insulation. Most often it fills the space between the floor beams, less often it is laid on top of the floor on the rough flooring or screed. If the attic is not supposed to be operated, then the thermal insulation is laid without waterproofing and wind protection.
Waterproofing. Layer made of diffusion membrane or perforated polyethylene. It is installed only in the case of operation of the attic, it fits under the flooring or floor covering.

If the use of the attic is not planned, then there is no need for a waterproofing device on top of the insulating layer. She is transferred to the slopes, where she does the work of protecting the entire roofing system from atmospheric water. The insulation layer on the floor also does not need 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 unexploited attic. They are laid directly on the logs if plate or roll material is used. The ladders are installed on the legs, if the insulation was formed by backfilling expanded clay. Heaters loosely laid in the attic must be periodically "loosened" so that the insulation properties do not decrease from caking.

Technological subtleties of laying a vapor barrier

The vapor barrier layer under the insulation is laid in the form of a pallet with the entrance of a kind of bumpers on the walls. Those. so that this barrier is not only between the overlap and the thermal insulation, but also between the insulation and the parts of the walls in contact with it. Each beam or panel wall is obliged to cover the protective material.

The vapor barrier material is laid on the floor:

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

Regardless of the scheme of the overlapping device, 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 minimum volume. For this cloth roll material stacked with an overlap specified by the manufacturer, the size of which is indicated in the instructions, and glued to each other with single or double-sided tape.

The vapor barrier material should be rolled out over the ceiling as it was wound by the manufacturer. You do not need to turn or rewind anything. In order not to confuse the laying sides, the manufacturer designates the side in contact with the overlap.

How to choose suitable material

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

The oldest version of a steam protection device is oily clay, which was used to process the ceiling from the bottom or top. Together with clay, a dry soil-vegetation layer was used, preventing the penetration of hot air in hot weather and cold air in cold weather. Fine peat, shavings, sawdust, dry foliage and similar materials can be used instead of earth.

Outdated insulation varieties are now replaced with materials specifically designed to resist steam and heat leakage. Their installation is much easier and much faster. However, in terms of insulating properties, they are inferior to the old proven methods.

For the device of vapor barrier protection of the attic floor, they 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 imply an increase in humidity levels above standard values.
Films made of polypropylene and polyethylene... Water vapor permeability is calculated in units, approximately 3 - 5 mg / m² per day. Most of these are reinforced materials that are resistant to temperature extremes, mechanical stress and UV radiation. Suitable for arranging wooden floors under a backfill insulation.
Foil-clad vapor barrier membranes... Water vapor permeability averages 0.04 - 2.55 mg / m². They are used for arranging rooms with high humidity and unstable temperature background: saunas, steam rooms of Russian baths, swimming pools, combined bathrooms.
Anti-condensation diffusion membranes... Their steam permeability varies over a wide range from 3 to 15 or several tens of mg / m². These are the newest multipurpose varieties. In an exploited attic floor, they can be installed on the lower and upper sides of the thermal insulation.

Anti-condensation types are produced in the form of double-sided polymer membranes. On the one hand, which should be turned towards the steam, they are rough, which prevents the formation of dew. The opposite side is smooth and prevents moisture from entering the outside.

Video about the rules of the vapor barrier device

An example of laying a vapor barrier roll material on the ceiling:

A video about the specifics of laying a vapor barrier film:

How to distinguish a vapor barrier material from a waterproofing option:

A vapor barrier built 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.

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

Cold attic vapor barrier, when using foil materials, in addition to its main function, it allows 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 pass steam (only vapor barrier).
Foil vapor barrier- does not allow steam to pass through and reflects heat radiation (steam and heat insulation). Such a vapor barrier is mounted with the foil side to the premises.

Vapor barrier of attic floors with foil materials due to its characteristics, it is the most preferable for the construction of 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 to the attic, provide attic staircase with insulated hatch (Thermo). To get out of the attic to the roof, we recommend installing blind or glazed hatches on the roof (Velux, Vilpe, etc.)
Para- or super-diffusion moisture protection membrane - for effective removal a pair of insulation.
Insulation - mineral wool slabs. The recommended thickness for the Moscow and Leningrad regions is 300mm. 200mm are laid in the inter-girder space, the remaining 100mm 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 postpone the installation of the insulation as much as possible - no earlier than 6 months after the end of the construction of the box of the house. Because for the construction of floors, mainly timber is used natural moisture... The timber must dry out properly, otherwise there is a high probability of damage to the wood by fungi and mold, which entails additional costs for dismantling / installation work and processing of wood with bleaches and antiseptics.
Counter grill 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 board of 50x200mm or a bar of natural moisture 100x200mm is used.
The lathing is the basis for laying insulation. It is recommended to use a 100x20 (25) mm board as a lathing and lay it in 70-80mm increments. The resulting cracks will form an additional air thermal layer under the insulation. That. the plates (mats) of the insulation will not lie on the vapor barrier film, but on a rigid base, already under which the vapor barrier will be located. This solution eliminates the likelihood of accidental damage to the vapor barrier or pushing it through when laying insulation, during maintenance and repair work of the roof and attic. In this case, you can proceed to interior decoration premises, and postpone the installation of insulation as much as possible (see above).
Attic floor vapor barrier on wooden beams- fastened with construction stapler from below to rough ceiling(crate), which allows you to cut off pairs from the entire structure of the floor. It is necessary to overlap the rolls of vapor barrier at least 15-20 cm and carefully glue them with aluminum adhesive tape. It is imperative to form gaps on the walls of 15-20 cm and carefully glue them (start under plaster and other wall finishes). Thoroughly seal the places of passage through the attic ceiling of chimney, ventilation pipes and other utilities with the help of special sleeves. Best material as a vapor barrier is polyethylene film high density from 200g / m² and more.
Close attic - the final ceiling is attached to the vapor barrier... Along the lathing, guides, the final ceiling is installed (OSB, plasterboard, etc.). For the best fire protection it is recommended to "sew up" the ceiling with drywall sheets in 2 layers.

Vapor barrier for the ceiling of the cold attic (diagram):

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

The attic is a 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, engineering networks can be laid. The temperature difference in the residential area and the technical one should be 3 ° -4 ° no more. Therefore, the technical room requires insulation.

Attic construction with overlap

The construction of an attic, which undoubtedly expands the living space, is much more expensive, requires certain knowledge, time and labor. The device of a cold attic floor is several times cheaper and easier.

The device of the attic floor on wooden beams is a puff pie:

boardwalk or roll;
vapor barrier;
ventilation gap;
insulation;
ventilation gap;
vapor barrier;

Ventilation is carried out through gables or roof slopes. Dormers are also made, 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 shape triangular, oval, they are placed at a height of 1 meter from the floor, equipped with gratings, blinds. Through them it is convenient to go to the roof for its inspection, maintenance, checking the chimney, antenna and other things.

Attic beams

The overlapping of the attic is done on wooden beams after the installation of the supporting elements is completed. This is the easiest and most optimal way for the competent arrangement of the technical area.

The construction of the attic floor is usually made of wooden beams. These support 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, crane;
availability of wood as an inexpensive material;
speed in work, the ability to install an attic floor in a day or two;
the ability to use any soundproof materials.

For the manufacture of beams use conifers wood resistant to moisture, decay, fungus. The cross-section of the beams for the attic floor must correspond to the load; climatic conditions, the thickness of the insulating material must be taken into account. The dimensions of the beams are 150x200 mm, if a serious load on the attic floor is expected. For example, it is planned to install a water tank, a transformer. With a minimum load, beams of 100x150 mm are used.

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

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

Installation of wooden beams of the attic floor

The device of the 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 processed special composition, which protects against decay, swelling and other troubles, the edges of the beam are wrapped in roofing material, then finished item goes upstairs.

2. Laying in two ways:

without protrusion beyond the outer walls;
with release for the outer walls.

It is necessary to lay along the length at the right distance in relation to other structural elements, with any method of laying it 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 timber fixed with thick nails or steel studs into the walls along the perimeter;
roofing material is laid under each beam layer to ensure waterproofing;
the pitch of the wooden beams is selected from the dimensions of the thermal insulation material.

3. The attic floor on wooden beams is carried out taking into account the arrangement of the roll, which is a covering of boards, slabs. Waterproofing, vapor barrier, insulation are placed between the upper and lower rolls. The lower flooring is made on supports to which the boards are attached, but it is better to use slabs, plywood sheets with a thickness of 15-20mm. Fasteners are carried out with self-tapping screws with a pitch of 10-15mm to securely hold the heat-insulating materials.

In order to mount the most durable structure, you need to fill on the bottom of each beam wooden blocks 50x50mm, they form a ledge on which boards or sheets are placed. You need to fix the roll to the bars also 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 repaired, hidden. Such a structure should be mounted if the active use of the attic is planned.

The value of vapor barrier and methods of its installation

The vapor barrier of the attic floor ensures the safety of the wooden floor. It extends the life of the roof, contributes to the creation of an optimal microclimate in residential premises, taking away excess moisture, and prevents heat loss. The choice of material for vapor barrier should be carefully, without intent to save money.

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

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

polyethylene;
polypropylene.

The canvases reinforced with a special mesh can be perforated. You can also use non-perforated film, leaving gaps during installation. The reinforced film has a metallized surface. The film spreads down a metallized surface to reflect heat loss.

The fiber layer absorbs moisture and then naturally evaporates. The materials are durable and resistant to ultraviolet rays.

There are also other vapor barrier materials that can be used to equip an attic overlap with wooden beams with a vapor barrier. These are varnishes and mastics, asphalt, bituminous, bitumen-kukersolny. Today, such materials are rarely used, preferring nonwoven fabrics of synthetic origin. These are the so-called "breathing membranes", capable of passing moisture, air, multi-layer, single-layer, equipped with aluminum foil.

The material is laid with an overlap on the wall by 20 cm, fixed with a stapler, rough side down.

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. The steam condensing on the beams can contribute to the damage of wood by fungi and mold, thereby reducing the service life of the structure. Condensing in the thickness of the insulation, it increases heat loss in the house, because water itself is a good heat conductor. In addition, water, freezing in the thickness of the insulation in the cold season, destroys the polymer bonds of the fibers and reduces the service life of the material.

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

Film vapor barrier- does not pass steam (only vapor barrier).
Foil vapor barrier- does not allow steam to pass through and reflects heat radiation (steam and heat insulation). Such a vapor barrier is mounted with the foil side to the premises.

Vapor barrier for the attic "pie":

Attic floor (ladders) - necessary for maintenance, repair of the roof and attic space. In order to get to the attic, provide an attic staircase with an insulated hatch (Thermo). To get out of the attic to the roof, we recommend installing blind or glazed hatches on the roof (Velux, Vilpe, etc.)
Para- or super-diffusion moisture-proof membrane - for effective removal of steam from the insulation.
Insulation - mineral wool slabs. The recommended thickness for the Moscow and Leningrad regions is 300mm. 200mm are laid in the inter-girder space, the remaining 100mm are laid perpendicular to the laid layers - counter-insulation. For comparison - building codes in Finland determine the thickness of the insulation from 400 to 500 mm. It is recommended to postpone the installation of the insulation as much as possible - no earlier than 6 months after the end of the construction of the box of the house. Because for the construction of floors, they mainly use a timber of natural moisture. The timber must dry out properly, otherwise there is a high probability of damage to the wood by fungi and mold, which entails additional costs for dismantling / installation work and processing of wood with bleaches and antiseptics.
Counter grill 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 board of 50x200mm or a bar of natural moisture 100x200mm is used.
The lathing is the basis for laying insulation. It is recommended to use a 100x20 (25) mm board as a lathing and lay it in 70-80mm increments. The resulting cracks will form an additional air thermal layer under the insulation. That. the plates (mats) of the insulation will not lie on the vapor barrier film, but on a rigid base, already under which the vapor barrier will be located. This solution eliminates the likelihood of accidental damage to the vapor barrier or pushing it through when laying insulation, during maintenance and repair work of the roof and attic. In this case, you can proceed to the interior decoration of the premises, and postpone the installation of insulation as much as possible (see above).
Attic floor vapor barrier on wooden beams- is fastened with a construction stapler to the bottom of the rough ceiling (crate), which allows you to cut off the vapors from the entire structure of the ceiling. It is necessary to overlap the rolls of vapor barrier at least 15-20 cm and carefully glue them with aluminum adhesive tape. It is imperative to form gaps on the walls 15-20 cm and carefully glue them (start under plaster and other wall decoration). Thoroughly seal the places of passage through the attic ceiling of chimney, ventilation pipes and other utilities with the help of special sleeves. The best material as a vapor barrier is a high density polyethylene film from 200g / m² and above.
Close attic - the final ceiling is attached to the vapor barrier... Along the lathing, guides, the final ceiling is installed (OSB, plasterboard, etc.). For the best fire protection, it is recommended to "sew up" the ceiling with plasterboard sheets in 2 layers.

Vapor barrier for the ceiling of the cold attic (diagram):

Description

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

roof covering;
external attic walls;
insulated overlap between the attic and the living quarters under it.

It should be noted that the insulation of the ceiling of the cold attic with mineral wool or other heat-insulating material can be carried out both from above and from 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 coating. This is achieved by reducing the number of superstructures protruding above the roof, which, as a rule, are its weakest points;
ease of use. The available internal under-roof space allows you to easily inspect and maintain all floor and roof structures;
the overlapping area is less than the area of the pitched roof, respectively, the area of possible heat loss is reduced;
the presence of an additional operated premises.

Ventilation organization

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

removal of excess water vapor penetrating through the floor from the bottom of the residential part of the building in order to prevent the appearance of condensation and moisture insulation and roof truss system;
creation of an optimal microclimate.
Ventilation occurs due to two types of vents:
eaves (the air passing through them is called supply air);
ridge (exhaust air passes through them).

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

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

Often, additional ventilation is performed through dormer windows installed on the gables or roof slopes, which assist in 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.

Usually, dormer windows are made of three types:

rectangular;
triangular;
semicircular.

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

In order to avoid the entry of birds, the air vents are supplied with protective nets or grilles, and blinds are installed on the dormer windows.

Thermal insulation options

The design of the cold attic can be used in buildings of any number of storeys. One of the prerequisites for its normal operation is high-quality insulation of the floor. It is performed in one of two ways:

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

Thermal insulation from the attic side

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

The sequence of stages of work:

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

This node is one of the many possible, fulfilling the basic requirements for insulation of the ceiling of a cold attic and allowing you to get the following advantages:

due to the presence of a vapor barrier, moisture does not enter the insulation;
DSP cover 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 fungus or mold).

Thermal insulation from the inside of the living room

The device of the ceiling in a private house with a cold attic and insulation from the inside is performed much less often, since the work is accompanied by a number of disadvantages:

the ceiling level goes down;
carrying out work on thermal insulation violates the finish, if it has already been completed, and requires its subsequent repair;
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 the comfort of living. For this reason, the use of mineral wool is not recommended. In addition, it is always advisable to leave a ventilation gap between the 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 (foam):

first, a crate is installed, on which drywall will subsequently be attached. In this case, the thickness of the lathing timber should be 2-3 mm more than the thickness of the insulation, and the pitch of the lathing should be 1-2 mm less than the width of the foam;
after that, the insulation is fixed between the lathing bars with additional fastening with dowels to the ceiling;
plasterboard or stretch ceiling is attached as a finishing finish to the suspended ceiling.

There are many other possible methods for thermal insulation of the ceiling, but with all the differences in the technologies and materials used, the basic principles should be consistent with the above.

Conclusion

The device of a cold attic with competent performance of work and compliance with the requirements of technology is an effective and expedient constructive solution.