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 constructive decision... 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.

Description

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 heat-insulating material can be carried out 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 structures of the floor and roof;
• overlap area less 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 a cold attic to be fully manifested, it is necessary to correctly and competently solve several issues related to insulation attic floor, and proper ventilation cold attic.

Organization of ventilation

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 of an optimal microclimate.
• Ventilation occurs due to two types of vents:
• cornice (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. air area 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 treats the same different options 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 along 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 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 gratings, 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 overlap. 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. Insulation for the ceiling for a cold attic can be used in a variety of ways: mineral wool (the most commonly used option), polystyrene, expanded clay, etc.

The sequence of stages of work:

• vapor barrier device (ordinary PVC film or modern materials, having much higher performance characteristics);
• installation of thermal insulation from mineral wool in two layers;
• creation protective coating made of 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 (for an even greater increase in service life, it is recommended to treat the surface of the cement-bonded particle board with antiseptics, which significantly reduce the likelihood of the appearance of fungi 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 level of the ceiling decreases;
• 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 recommended 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 false 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 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 adherence to technology requirements is an effective and expedient constructive solution.

The attic is a technical area that completes the building. Attic - Utility room, it is rarely used as a living space, equipment necessary to ensure the life of the house can be placed here, network engineering... 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 certainly 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.

Attic overlap device wooden beams is a layered cake:

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

Ventilation is carried out through gables or roof slopes. Dormer windows 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 inspection, maintenance, checking the chimney, antenna and other things.

Attic beams

The overlap 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 load-bearing elements have a number of advantages:

• maximum coverage 4.5 m between supports;
• light weight, load on the building, savings on the foundation;
• ease of installation, without the use of lifting equipment, 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, it should be taken into account climatic conditions, the thickness of the insulating material. 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 60-100 cm (the distance between the beams), add 2 pieces to the resulting value, which will fit on the walls. Beams must 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 the finished element rises up.

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 required 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 heat-insulating 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, so that the heat-insulating materials are securely held.

In order to mount the most solid construction 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 decoration 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.

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

The subfloor is mounted on the same bars from above. But before you start the last stage should do:

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

The finished structure is important element overlapping the roof and the entire structure.

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 one side there is a rough surface that absorbs moisture, the other side with a 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 evaporates it naturally. The materials are durable, resistant to ultraviolet rays.

There are also other vapor barrier materials that can be used to equip an attic overlap with wooden beams with 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.

The construction and repair of a private building requires that it be necessary to take into account the need for thermal insulation of all enclosing structures - walls, floors and attic covering(cm. ). The result is a decrease in heat loss, which means significant savings in payment utilities during heating season... However, at the same time, one should not forget about such works as the vapor barrier of the attic floor, which allows maintaining not only the appropriate temperature in the room, but also the optimal humidity.

The choice of material for the vapor barrier of attic floors

To create an effective vapor barrier floor slabs most often they choose the most ordinary and inexpensive materials: glassine and polyethylene. Although the resulting protection of the building from steam penetration from the outside is not very strong and short-lived. It is possible to increase the reliability of the structure by using more expensive and durable vapor barrier membrane films, which are easy enough to find on the market and on the network at quite affordable prices (see). Despite the fact that glassine can be used as a vapor barrier, it is practically not used. Fragile material will last no more than 3-4 years.

For buildings with high humidity(saunas, bathrooms of residential buildings) inside they use a special foil vapor barrier that can also reflect thermal radiation.

In some cases, combined foil-coated thermal insulation is used. Due to its qualities, this material increases the thermal insulation and vapor barrier properties of the enclosing structures, including attic and interfloor floors. However, it is quite expensive and is not suitable in cases where the attic of an already built building is protected from steam.

Requirements for the vapor barrier of the attic floor

When installing a vapor barrier in the attic, certain rules must be observed:

• the film is placed from the side of the room, in front of insulating layer... This is necessary so that wet steam does not penetrate into the insulation;
• the vapor barrier material must cover the surface completely, without gaps and holes that could compromise the protection. Because of this, the film is attached construction stapler(setting nails with wide heads) or using a thin wooden slats pressing the vapor barrier to the ceiling;
• layers of membrane film are applied with an overlap of 8 to 10 cm and glued with a special adhesive tape. In the same way, problem areas are closed, including corners and abutments to openings.

You need to pick up among fibrous, mineral wool materials.

Such a floor and ceiling is not afraid of high temperatures, but absorbs moisture.

Vapor barrier materials should not be stretched to their maximum. Under the influence of temperature extremes, the film will shrink and become damaged over time. The slack should be about 10–20 mm. And when choosing the sides of the installation, you should turn the film with a rough surface towards the under-roof space; as a result, moisture will collect outside the room, and not vice versa.

An already insulated surface should be protected from damage from sharp objects. For example, nails with which other insulation is attached, otherwise the broken integrity of the film will make the protection practically useless.

Preparation for the installation of vapor barrier on ceilings

One of the most popular ways to equip an attic floor vapor barrier is a design called "pie". It provides for the use of insulated structures and special hatches (glazed or deaf), as well as a superdiffusion moisture-proof membrane. The stages of preparation for laying a vapor barrier consist of the following actions:

• calculation of the required amount of heat and vapor insulation (see);
• selection of thermal insulation and vapor barrier materials (for example, mineral wool boards thickness of 250-300 mm and film-membrane);
• installation of thermal insulation, which should be installed no earlier than six months after the completion of the construction of a new building (for old houses, installation is carried out at any time);
• installation of the crate leaving a ventilation gap, which provides fairly effective ventilation and removal of steam from the protective film.

For the construction of the lathing, boards with a section of 10x2.5 cm are used, stacked with a distance of 7 to 8 cm from each other. Laying the film not on thermal insulation, but first on wooden frame allows you to exclude accidental damage (punching or piercing) of the insulation during its maintenance or repair. In addition, the installation of vapor barrier materials on the crate can be performed at any time, postponing almost until the very completion of the construction of the building.

The final stage of laying the vapor barrier of attics and ceilings

Laying the vapor barrier for floors on a wooden rough ceiling (lathing) using a stapler ensures maximum tightness and cuts off steam from the rest of the structure. In this case, the insulation of joints and intersections of the material with various structures is mandatory:

• chimneys;
• ventilation and water pipes;
• antenna cables and other utilities.

The process of installing the vapor barrier is completed by attaching its edges to the clean ceiling. And to the crate, on which the film has already been laid, a final ceiling made of OSB or other materials is attached. In approximately the same way, vapor barrier of interfloor ceilings is performed in wooden house... The differences are that the design does not require a ventilation device. And the insulating film is simply fixed with tape to the bottom of the beams.

In principle, it is impossible to complete if there is no special equipment.

Despite the fact that it is impossible even theoretically to achieve complete isolation of attic floors from steam, with the help of such structures, you can get good protection against moisture. The main thing is to adhere to all styling requirements and choose suitable materials... While the experience of the contractor is practically irrelevant, the simplicity of the method of laying the vapor barrier allows you to perform it even on your own.

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

Peculiarities

The construction of almost any house involves design attic spaces of various types... The simplest ones are considered to be cold attics, which are not able to maintain the temperature at the same level.

Such a structure consists of several main parts:

• Roof covering. In most cases, there is no insulation here, but only itself is used finishing material for protection from rain.
• Exterior walls.
• Overlapping. A warm attic can be supplemented with a layer of insulation.

What is it for?

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

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

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

Types and materials

Vapor barrier is a generic name various materials... Previously, as such a product, a person used oily clay, which was not able to pass moisture. Today, many different modifications of polymeric materials ("Izospan", etc.) have appeared on the market, which are much easier to install.

This type of vapor barrier materials is the most widespread and demanded.

This group includes the following types of products:

• Polyethylene film. Relatively inexpensive material which protects well against steam penetration. It can be used only at moderate temperatures, which will not lead to structural damage. 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 already tolerates temperature changes much better than products based on polyethylene. It easily resists ultraviolet light, which increases its service life several times.

Today, manufacturers also add viscose and cellulose to the 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 able to pass moisture well in only one direction. Therefore, when laying, it is important to take into account the position 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? What is the best choice? Tips and tricks for installation. What are the advantages of foil-clad material?

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 does not give a warm humid air going up to leave the room. Different materials can be used to create a vapor barrier in different situations:

• 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 onto 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 to be precise, 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.

These are special materials with limited breathability. They allow air to pass 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. Applied to the surface in the same way as ordinary 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 seal the ceiling from the side of the cold attic.

In addition, it will be a very effective solution if processing flat roof in buildings that do not have an attic. In this case, a suitable insulation is laid on top of the applied insulator and the entire structure is waterproofed. In some cases, such 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.

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

Correct vapor barrier of the attic floor using wooden beams allows you to cut off water vapor from interior space buildings from insulation. If a basalt wool-type insulation is used in this floor, which, when wet, loses its heat-insulating properties, then a correctly performed vapor barrier of the attic floor using wooden beams will save well on heating.

What do you need to know when starting work on the installation of films? First, the fact that vapor barriers are different. Indoors, you can use ordinary thick plastic films, which will cope with this work no worse than expensive specialized materials.

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

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

The vapor barrier is fastened with paper clips using construction stapler... If you are using non-specialized film, but ordinary film, you need to use paper clip pads. These can be pieces of polyethylene folded in 2 or 4 times.

Staples from above are also sealed with special tape for vapor barrier. Further, on the film from the side of the room, you can apply a base for finishing, or mount a lathing for a suspended ceiling.

Do not damage the film when mounting the lathing or applying the base. It is better to use the lathing and the rough ceiling first, and only then attach the finishing shelf to it, which will carry the finishing.

See more on this topic on our website:

1. Vapor barrier - which side to lay in the frame wall
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Can I use the film 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 quite possible. And for the frame, and.

Vapor barrier - which side should be laid to the insulation
When building a private house, the question is inevitable - which side to lay the vapor barrier to the insulation so that the structural elements will serve for more than a dozen years.

Floor in a wooden house - waterproofing and vapor barrier
The most common non-insulated floor in a wooden house, the hydro and vapor barrier of which is made according to the rules, will serve for a long time. Wood that does not, in this case, experience the influence of moisture.

How to work independently with wooden block House
Wooden houses are structures that are distinguished by reliability, aesthetics and environmental friendliness. Despite the simplicity and naturalness of the material, structures made of it are quite expensive and affordable.

Correct vapor barrier of the attic floor using wooden beams
Correct vapor barrier of the attic floor on wooden beams will keep the ceiling insulation intact and prevent moisture from reducing its thermal resistance. See the diagrams on our website.

Ceiling vapor barrier last floor- an obligatory part of complex work on the insulation of the cold attic floor. For concrete foundations it is enough to seal the seams tightly, lay a vapor-tight film on top of the plates with a continuous layer, then insulation and waterproofing membrane... Vapor barrier and wood floor insulation is done differently.

What is a vapor barrier for?

• protect the insulation from moisture vapors from entering it together with warm air from a heated room,
• prevent the creation of conditions for the wetting of construction materials,
• protect living quarters from mineral wool particles entering them.

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

The entire structure of the "pie" of the insulated floor of the cold attic must meet the requirements of SP 23-101-2004, which is regulated by the norms for the design of thermal protection.

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

Installation rules

Wooden floors are beams with boards or panels of the rough ceiling stuffed from the side of the room. Such a device determines the specifics of the order of the layers. If on concrete floor the vapor barrier is laid on a slab under the insulation (just like when insulating a flat roof), then in this case it must still protect wooden elements constructions.

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

1. They equip the floor - a rough ceiling (number 8 in the diagram) is hemmed to the beams.
2. From 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-, three-layer structure) or a heat-reflecting vapor-hydro insulation, then the anti-condensate rough surface or metallized layer should face the interior of the room.
3. The overlap between the panels, regardless of the direction of laying, is made 15 - 20 cm.
4. The edges of the vapor barrier layer along the perimeter are brought out to the walls and fixed to them.
5. The joints of the canvases and the perimeter are glued with a vapor barrier tape.
6. Between materials with anti-condensation or reflective surfaces and fine finish a gap is required on the ceiling. It is provided by stuffing a strip with a thickness of 4 - 5 cm.

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

Between beams to surface false ceiling mineral wool is laid (in soft mats or in rolls). The insulation layer is calculated so that the total reduced resistance to heat transfer 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 the insulation is required along the perimeter of the cold attic for a width of 1 m or more. In private houses, with a relatively small building area, they do it simply - a waterproofing membrane with a high vapor transmission (superdiffusion) ability is laid over the entire surface of the heat-insulating layer. The vapor transmission capacity of waterproofing is needed to weather excess moisture from the insulation when the temperature and humidity level of the atmospheric air change.

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

Counter-rails with a thickness of 4 - 5 cm (number 3 in the diagram) are stuffed along the beams, which ensures the ventilation mode of the heat-insulating layer.

The floor is laid on the counterrails.

What you need to know to keep from dripping from the ceiling

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

• For a continuous pitched roof, ventilation openings should be at least 0.1% of the overlapping area.
• Have pitched roof made of piece roofing materials, you can do without ventilation holes- sufficient gaps between the elements of the roof.

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

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

the fact of the matter is that the program shows the possible formation of condensation under the film and in the upper part of the beams, but this is provided that outside from -22 degrees and humidity 86%, and in the room +20 and humidity 55%, but it seems to me that under such conditions, in winter, humidity in the room from 55% is not realistic, it is necessary in the room for a very long time and to dry the wash a lot.

In general, it is better to add another 50mm insulation perpendicular to the upper beams. Then we get a cake of 250 mm and a layer of insulation up to a beam of 150 mm (And heat and there is no possible risk of condensation). And at -22 there will be no condensation

Added after 6 minutes

Having shoveled a bunch of information, I did not come to an unambiguous answer.
There is a house with a cold attic, the floor is wooden beams, the bottom is a board, the roof is metal tiles. I want to insulate the attic floor with mineral wool.
There is a superdiffusion three-layer membrane STROTEX 1300 BASIC can it be used as a vapor barrier under the insulation?

Under min. cotton wool, vapor barrier is laid on the side of the room - this is a must. The main task of which is to protect the enclosing structures from saturation with water vapor from inside the premises and the formation of condensation in them during the cold season. This is necessary because even with a slight moisture content of 1-2%, the thermal conductivity of fibrous thermal insulation increases by 20% or more. Waterlogging of the insulation not only increases heat loss, but is often the cause of fungal infection of wood and corrosion of metal parts.
The superdiffusion device does not fit in place of the vapor barrier.

And you need a superdiffusion membrane in order to remove excess moisture (water vapor ...) from the structure to the outside, as well as to protect the insulation and internal elements of walls and roofs from weathering and moisture from the street.

Question about the vapor barrier of a cold attic
a question about the vapor barrier of a cold attic Thermal insulation of a roof, attic

Ceiling insulation. Vapor barrier. Cold attic.

Question 1. What is the best way to fix drywall to the ceiling: along the guides or can you screw it directly to the board if they are even? You write, when the ceiling is lined with plasterboard, then vapor barrier is not needed, unless only as a material that protects the room from the dust of the heat insulator.

Question 2. Is a vapor barrier NOT needed in either case (for example, Isospan B)?

And about mice. Do mice start in a min. cotton wool? I thought they loved styrofoam, and min. cotton wool is ignored, but here they write that supposedly in min. moths and mice can start on cotton wool. And I did not want to sew up boards with boards when insulating from the attic.

Question 3. If the insulation is min. cotton wool, how to be? Maybe sprinkle with expanded clay? For example 10 cm. Min. cotton wool and 5 cm expanded clay. If you use expanded clay, then what fraction? Is 10-20 mm a suitable fraction? And is it necessary to close the top of the insulation with waterproofing (for example, Isospan A)?

Question 4. Do you consider warming with sawdust at all? If so, when can they be used? What are the correct layers of heat and sound insulation using sawdust?

The last question (sorry). What is the ideal heat and sound insulation for you in my case?

I already answered the topic of your ceiling insulation literally 2 questions ago. Here is a link to it. Here I will briefly answer the clarifications.

Question 1. Better on guides. And much better. When the ceiling is suspended, it will not crack at the seams. Again, the soundproofing will be better, and this issue, I know, worries you very much.

Question 2. Ceiling vapor barrier is always shown and useful. I wrote that in the case of a plasterboard ceiling, you can get by with a light glassine, but not with plastic wrap. Any material with a high resistance to vapor diffusion (with low vapor permeability) can be used as a vapor barrier. See the characteristics of materials in the vapor permeability reference books. A lot of them.

Question 3. If you want to sprinkle cotton wool with expanded clay - sprinkle it, But this will not give the effect that you expect or will give, but less. Fraction - the less the better. It won't work against mice. Only mousetraps and poisons help against mice. And also manic cleanliness. And nothing else.

Question 4. Sawdust is flammable and even explosive. In order to use them, they must be treated with fire retardants, and they are poisonous (mice do not live). Flame retardants do not work forever and sawdust can eventually crumble, rot and start to smell bad. In one way or another, they will lose their properties. Well, the layer of sawdust should be 2 times more than cotton wool, namely 30 (.) Cm. And sawdust is not an effective sound insulator.

The last question. I answered it in my last letter (link above).

Thanks for your questions. Ask more.
Dmitry Belkin

Ceiling insulation
Ceiling insulation. Vapor barrier. Cold attic... Question 1. What is the best way to fix drywall to the ceiling: along the guides or can you screw it directly to the board if they are even? You write,

The question asked: aleshkas

Between the 2nd floor and the attic there will be wooden floor, from the side of the 2nd floor, the ceiling was covered with a rough board 25 mm thick close to each other, there are small gaps of 1-4 mm between the boards, the insulation has not yet been laid down. I had a question on which side should I lay the vapor-proof film under the insulation:

1. from the side of the 2nd floor to the draft ceiling,
2. from the side of the attic to the wooden floors and the subfloor (from the side of the 2nd floor it is the subfloor ceiling) and then the insulation directly onto the foil?

What density is usually used for insulation? Which is better, slabs or rolls?

Comments (1)

I understand that this is the same for the region of location. Chelyabinsk region what's in your other branch. I made a calculation for Chelyabinsk, according to the thickness of the insulation. You need 150 mm.

With regard to the location of the vapor barrier. The fact is that it can be positioned either way (according to the options that you wrote), both options are correct. Do what is more convenient. It is easier to spread the film over the top of the floor.

As for the density of the insulation. As a rule, you can take soft, rolled insulation with a density of 20-30 kg / m3. You cannot walk on the insulation, so you will need to leave the technological passages. Place, for example, bricks and walk-through boards on them.

I'll ask again, just in case. Your attic is cold, isn't it? Is the roof slope itself not insulated? It is also important to provide for ventilation in the attic (with windows in the gables). Then the mineral wool works fine.

Thanks for the answer.

No, the vapor barrier is only at the bottom of the insulation. From above, the insulation is either completely open (if there are no leaks in the roof), or it can be closed, but not with a vapor barrier, but with a superdiffusion membrane. You can put it directly on the insulation. What kind of company these materials will be, I can’t tell, I don’t know what you have in the region. But, it doesn't have of great importance... The most common vapor barrier is suitable, and the superdiffusion membrane should have a vapor permeability of 1000 g / m2 per day and above. If you need a firm, then write what you have, then I can tell you.

By airing the attic. Do you have ventilation ducts from below, not from the attic? Even if in the attic we make a ventilation grill into these channels, then an inflow is also needed for all this to work. Here the inflow will be the windows. Specify, please, on the ventilation ducts (where they come from, and whether they have a lattice from the attic).

I will add according to the requirements for the windows. They are standardized by the area of ​​the attic. Should be in the opposite walls of the pediment, with a total area of ​​at least 1/500 of the attic floor area. Specify on the ventilation ducts and overlap areas, I will estimate them then.

Sorry, I misunderstood a little and wrote incorrectly (I'm not a builder), I have an envelope type roof, L-shaped, with a slope on all sides and an inner endovina. Ventilation ducts on the ridge on top are 3 pcs.

Insulation can be found almost of any firms and brands: Isover, Ursa, Linerok, Knauf, Techno, AKSi, Tisma, Baswool.

For films: Izospan, megaflex.

I will answer by stamps in a personal. Answer me to the question about the ventilation ducts, where they come from (start) and whether there is a grill from the attic room to the ducts. I can't say anything about the windows without this information.

They put a vapor barrier last year, from the top of the mineral wool, it was cool, in the spring they began to look at what was going on, there were almost puddles under the vapor barrier! they removed the vapor barrier, dried it, and put in a heater, without a vapor barrier, shouldn't moisture stand there? where is the mistake? or is it supposed to be?

Forgive me, please, but it is completely unclear where exactly you put these layers. What mode of operation in a room also matters. Is the ventilation working? We do not analyze the questions asked in the threads of other readers. If the question is relevant, please post the question on the website, in the Question-Answer section, the Ask a Question button (orange, on the right).

Thank you for understanding!

Having shoveled a bunch of information, I did not come to an unambiguous answer. There is a house with a cold attic, the ceiling is wooden beams, the bottom is a board, the roof is metal tiles. I want to insulate the attic with mineral wool.Is there a superdiffusion three-layer membrane STROTEX 1300 BASIC can it be used as a vapor barrier under the insulation?

If we put the vapor barrier under the mineral wool, we’ll be afraid that we will get the locking of the tree in pairs, with all the consequences, and this moisture will not go anywhere from there. - on top of the insulation - I want to put a superdiffusion membrane

We do not analyze the questions asked in the threads of other readers. If your question is relevant, then ask it, please, in the Question-answer section (orange button Ask a question, on the right). And fully state your situation and attach plans and ask questions point by point.

Warming and
Hello! & Amp, nbsp, Between the 2nd floor and the attic there will be a wooden floor, from the side of the 2nd floor, the ceiling was covered with a rough board 25 mm thick close to each other,

Attic floor vapor barrier

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 during 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:

1. Film vapor barrier- does not let steam through (only vapor barrier).
2. 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":

1. 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.)

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

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

Attic floor vapor barrier
Vapor barrier of the attic floor The vapor barrier of the attic floor of a cold attic protects the wooden structures of the ceiling and the insulation from steam from entering them from the premises of the house. Steam