Vapor barrier of the attic floor of a cold attic

Using additional protection for the attic floor from condensation and water helps maintain a favorable climate in the main building, without high humidity, dampness on the walls and mold in the corners.
Steam and waterproofing of the attic floor completely protects against leaks and extends the service life of all structural materials that are part of the wall frame.

Is it possible to do without vapor and waterproofing, what are the basic requirements for its production and installation, what errors lead to, and other nuances, read more in this article.

Vapor barrier of attic floor

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

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

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

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

, vapor barrier of attic floors with foil materials is most preferable when building a reliable and heat-efficient house made of aerated concrete, brick or monolith.

Application of extruded polystyrene foam

Polystyrene foam (expanded polystyrene) is a loose material, so it is used when it is necessary to insulate a floor made of joists and beams. For thermal insulation of slabs, extruded polystyrene foam is used, which is denser than conventional foam.

Before laying it, the surface of the base is leveled. On the warm side of the floor, vapor barrier is not needed, since concrete slabs have virtually no vapor permeability. A vapor barrier film is laid out on the prepared base. Then slabs of extruded insulation are laid out in a checkerboard pattern. Polyurethane foam is blown into the joints.

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

Rolling flooring recommendations

In order to make the ceiling of the first floor, it is necessary to roll up. This stage of work can be carried out using a wide variety of materials.

Skating plan.

In the most common version, skull blocks are nailed along the side of the beam. Such bars should have a cross-section of 40*40 or 50*50 mm. They should not protrude below the main beam. It is on them that smooth boards will subsequently be attached, the thickness of which should be in the range of 10-25 mm. In order to line the ceiling, you can use sheets of plywood. Using sheet material, you can get a perfectly flat ceiling. The minimum thickness of plywood in this case should be at least 8 mm

It is very important to ensure that the edges of the sheets lie exactly in the middle of the beam

Instead of using cranial bars, you can make special grooves in the beams. In order to use this method, the cross-section of the beam must be thought out in advance.

As an option for flooring, the lower part of the floor elements can remain open; for this, the cranial elements are nailed not flush, but slightly higher. Thus, the flooring is carried out between the beams.

After the rolling is done, you can begin laying the floor of the second floor. If instead of the second floor there is an attic, then a subfloor is sufficient. If there is a room on the second floor, then the floor must be made of high-quality material. Wooden boards will be laid directly on the joists.

Why do you need a vapor barrier?

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

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

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

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

Roof insulation

Vapor barrier and roof insulation are reminiscent of those procedures for the internal partitions of a frame house, but there are certain differences.

Waterproofing is installed along the rafters, on which the sheathing is mounted. Subsequently, the roofing material is attached to it. The space between the rafters is used for installing insulation in the form of slabs.

It is necessary to create a gap between the insulation and waterproofing to allow moisture to escape and ventilate the structure. It is very important to ensure that the waterproofing layer is sealed. When thermal insulation comes into contact with moisture, it loses its beneficial properties.

The inside of the rafters must be lined with a vapor barrier. A sheathing is mounted on top of it, onto which finishing materials are attached. When the attic is properly insulated and there is a vapor barrier, you can install heating there. This will allow you to use it as a full-fledged living space.

So, the best vapor barrier for the entire frame house is achieved thanks to high-quality installed and correctly selected material. Then the membrane will fulfill its purpose - to prevent moisture from coming into contact with the insulation, and, if necessary, remove liquid from the “pie” of walls, floors and ceilings.

Installation rules

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

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

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

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

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

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

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

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

The floor is laid along the counter slats.

Requirements

Regardless of the type of attic (cold, warm) and the beams used during installation (wooden, reinforced concrete, metal), general technical rules for the arrangement and use of basic and protective layers apply to them.

At the same time, the formation of vapor and waterproofing is subject to a number of regulatory technical requirements , which include provisions relating to the ceiling itself and materials for installation - these are:

GOST R 58796-2020;
SNiP II-26-76;
SNiP 23-01-99;
SP 31-105-2002;
SP 17.13330.2017;
SO-002-02495342-2005;
SP 17.13330.2011;
MDS 12-34.2007.

Characterizing the listed standards, we can highlight the following main points regarding the arrangement of vapor and waterproofing:

The materials used must be produced in an industrial environment, be of the highest quality, have accompanying documents from trusted manufacturers, certificates and instructions.
The consumables used must belong to the non-flammable group “NG”.
Vapor barrier and waterproofing must be resistant to water and repel condensation well. They must be wrapped around all or part of the beams along the joists adjacent to the wall.
All materials used must be securely attached to the prepared surface using glue and fasteners.
During installation, you can use dense and liquid materials (for example, for waterproofing).
Between the layers of the cake, it is imperative to create a ventilation layer (at least 25 mm), which is formed under the sheathing, before laying the insulation, which is applied after the waterproofing.
The working material must adhere well to the surface and adhere to any substances.

In addition, vapor barrier and waterproofing products do not have to be expensive. They are also laid according to the spacing of steps between the beams (minimum 4 m), in accordance with the thickness specified in the work project.

Thanks to the technically correct creation of the cake, using steam and waterproofing, it is possible to create additional space, which is useful for various household purposes.

What you need to know to prevent dripping from the ceiling

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

For a continuous pitched roof, ventilation openings must be at least 0.1% of the floor area.
On a pitched roof made of piece roofing materials, you can do without ventilation holes - there are enough gaps between the roofing elements.

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

Which one to choose?

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

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

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

Ceiling vapor barrier in a cold attic

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

What is it for?

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

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

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

What is it and why

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

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

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

How to mount

Vapor barrier ensures the reliability and durability of the entire house structure. You need to understand which side to attach the vapor barrier, if it is not double-sided, and how to do it correctly. If you abandon this layer, then all the materials used on the roof will gradually begin to deteriorate and, over time, problems with the house will appear.

Installation of roof vapor barrier Source applesakhalin.ru

See also: Catalog of companies that specialize in engineering systems

This layer has its advantages:

UV protection;
high level of strength;
resistance to temperature changes;
multifunctionality.

Laying this layer has its own rules and requirements that must be taken into account. It is important to take into account the design features of the material. Different films are used on different sides of the insulating layer, carrying the opposite tasks discussed above. Materials may differ in installation method; there are single-sided or double-sided options. In the first case, the film is attached to a specific side, and in the second, both sides of the vapor barrier membranes are the same - this is a more practical option.

To find the required side, you must carefully study the manufacturer's instructions. But if nothing is indicated there, then you can determine the required plane yourself based on a number of factors. Izospan with the light side is mounted to the insulation. The fleecy side is the outer side, and the inner side is always smooth. Some manufacturers roll the rolls with the inside facing up, so when unwinding it is directed towards the floor.

Durable film option Source dekoriko.ru

Polyethylene and glassine

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

Electric heated floor
Installation of ventilation systems
Pipes for internal sewerage

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

Membranes

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

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

Video description

This video clearly shows the consequences of improper formation of a vapor barrier on a ceiling in a wooden house:
There are several different techniques used to attach the vapor barrier to the supporting structure:

Hardware.

Experts consider staples for a construction stapler to be the best option. This way, the material is fixed to wooden supports quickly, and damage is caused to a minimum. Some craftsmen place strips of cardboard under the staples before “shooting” in order to soften the blow and prevent through penetration.

In any case, it is recommended to additionally secure counter-lattice slats on top of the ceiling vapor barrier from inside the room. They are needed to reduce the likelihood of the film breaking due to stretching. Additionally, this creates a ventilation gap or space for laying utilities.

Scotch.

This involves the use of double-sided adhesive tape with a foam backing. It is better to choose from a group of plumbing samples, as they last longer under conditions of temperature and humidity changes. For reliability, you can supplement the canvas with a counter-lattice.

Using vapor barrier tape to fix the canvas Source bauemotion.de

Liquid coatings

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

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

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Cold attic design

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

. Although, it is undeniable that the attic will significantly expand the living space.

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

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

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

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

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

Steam and thermal insulation of a cold attic

For a roof with a cold attic, it is most important to minimize heat loss through the attic floor

. For both wooden and reinforced concrete floors, a vapor barrier is mandatory. It is laid on the ceiling itself and protects the insulation from vapors that can condense in the heat insulator after passing through the ceiling of the living room. Slab and bulk materials can be used as insulation. The ceiling pie consists of a vapor barrier, floor beams and insulation.

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

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

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

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

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

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

Attic waterproofing device

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

Metal roofs are most susceptible to corrosion, which occurs due to possible small leaks or condensation

.
Therefore, we once again draw your attention to the fact that ventilation plays one of the main roles in the fight against condensation.
.

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

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

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

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

Cold attic temperature

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

The effectiveness of a heat insulator can be assessed by measuring the temperature of the top layer of insulation. The electronic thermometer is immersed in insulation by 10-20 mm. The temperature readings taken should correspond to the values in the table below.

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

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conclusions

We talked about the basic principles of installing vapor barrier films and membranes in insulated wooden floors. The main approach is to protect the insulation from steam and, if water vapor gets into the ceiling, to escape. Those. do not lock the thermal insulation into two layers of vapor barrier , and this mistake is often made. And do not wrap wooden beams with vapor barrier, unless it is a film specifically designed for this purpose. Another nuance - ensure the tightness of the vapor barrier . Overlaps, joints, and junctions with walls, skylights, stove and ventilation pipes must be sealed with materials recommended by film and membrane manufacturers.

We recommend the topic Waterproofing in a cold attic, which tells you whether it is necessary to install waterproofing under the roofing.

What does improper vapor barrier lead to: real experience and repair methods
The correct “pies” of a frame wall, which are recommended by FORUMHOUSE users.
The most complete instructions on the RuNet for installing a roof window with the stages of installing a vapor barrier, a moisture-proof film and a gutter for condensate drainage.

Ceiling vapor barrier in a cold attic

Features of the design
Types of materials
Foil materials
Liquid products
Adviсe

A 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 floors from condensation and further destruction, and also prevents the appearance of mold and mildew in insulation boards.

Adviсe

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

The film material should be secured using staples or small nails, placing a thin wooden strip under the fasteners. This will allow the material to be better pressed to the base and will reduce the likelihood of accidental damage to the film.
The size of the overlap when installing any materials should not be less than 15 cm. The joints should be glued using a wide tape, and when installing materials made of foil, you should use foil tape.

Laying vapor barrier materials should only be done with thermal insulation.
During installation, it is recommended to carefully monitor the tension of the material: the film should be in a free position. This will prevent the material from rupturing when it is stretched and compressed under the influence of thermal changes.
To form insulation for the ceiling of a residential building, it will be sufficient to use a membrane or reinforced polypropylene film, and during the construction of bathhouses only foil vapor barriers should be used.

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

Properly selected material and proper installation will extend the service life of the ceiling, significantly reduce heat loss and make staying in the room pleasant and comfortable.

For more information about ceiling vapor barrier, see below.

Features of the design

A cold attic includes the surface of a gable roof 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 the ceiling, which also serves as the ceiling of the living space. When street temperatures drop, the ceiling becomes susceptible to condensation, the formation of which is caused by the temperature difference between its lower and upper parts. To prevent droplets of condensation from penetrating into the ceiling, the top is covered 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, moist air from rising upward. This technology significantly reduces heat loss in a living space and allows significant savings on heating. Vapor barrier must be performed on all types of foundations, including concrete and wooden floors. Isover slabs, glass wool or bulk materials can be used as insulation.

Vapor barrier film

A vapor barrier in a frame house is needed in order to stop moisture coming from the house to the street through the insulation, that is, it is installed only from the INSIDE of the house. Moisture occurs according to the laws of physics, since it is colder outside than inside.

Accordingly, if the outside of the room is warmer or the same temperature, then it is not necessary to install it (for example, between the first and second floors of one identical heated building). If we do not stop this moisture, the insulation will stop working and insulate our house, it will become completely wet. We remember that a frame house must have a thermos in order to be warm.

polyethylene film with a thickness of 200 microns (the thickest of those sold) is ideal for the role of a vapor barrier The rest of the newfangled films, which are just a marketing product, are not necessary to use for vapor barrier in a frame house.

In addition, regular plastic film is easy to find and buy.

It must be remembered that the vapor barrier must be as tight as possible . If you need to make holes in it (for sockets, for the passage of ventilation pipes, etc.), then you need to seal these places with special tape or sealant (butyl rubber). Perfectionists also glue holes from any fasteners in the wall; I have not done this yet.

Where is vapor barrier film used : In the walls of a frame house - from the inside In the floor of a frame house (lower floor) - from the inside In the ceiling of a frame house (upper floor) - from the inside

Installation of vapor barrier film by Finns on video:

Types of materials

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

Film vapor barriers

Film vapor barriers are the most popular and sought-after type, which is represented by polyethylene and polypropylene films and membranes:

Polyethylene is the most widely used. This inexpensive and practical material reliably prevents the penetration of steam, but has limitations in use. It is recommended to use this type of film only in warm climates under moderate temperatures: under the influence of extreme influences, it quickly loses its performance properties and is destroyed. The disadvantages include the low strength of polyethylene, which can lead to ruptures of the material even at the installation 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.

A more practical type of vapor barrier is polypropylene . This film tolerates thermal shocks 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 film with the addition of viscose and cellulose. This significantly increases the strength and hygroscopicity of the material. A prerequisite for using such a vapor barrier must 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 disrupted, which will lead to moisture in the ceiling.

The most modern and practical type of vapor barrier material is membranes. The insulator 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, and air is exchanged between the ceiling and the attic room. In the domestic construction market, the most famous is the Izospan model, the fleecy structure of which is capable of retaining condensate droplets and quickly evaporating them. Installation of a membrane coating requires the formation of a ventilation space designed to provide room for liquids to evaporate.

Foil materials

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

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

Dacron-coated kraft paper can 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 of detergents.
Foil fiberglass fabric 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 providing ceiling vapor barrier are represented by varnishes and mastics. The compositions are applied to the surface of the ceiling and, after complete drying, form a thin film that can retain moisture and allow air to pass through. This promotes good ventilation of the floors and significantly reduces the likelihood of mold and mildew.

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

Choice of insulation

The methods of insulating the ceiling of the upper floor of the ceiling along beams in a private house are very diverse. When doing the work yourself, the insulation is placed between the joists and provides reliable thermal insulation and noise protection. There are many options for insulating a structure, the most common of which are:

insulation with mineral wool;
laying expanded polystyrene (foam plastic or penoplex) on wooden beams;
filling with expanded clay;
insulation with sawdust;
filling the ceiling space with foam.

Each of these options has its own characteristics and advantages.

Mineral wool insulation

The material is available in two versions: plates and rolls. Insulating the attic floor with mineral wool has the following advantages:

Styrofoam

Foam plastic has become one of the most common materials for thermal insulation. It has earned its place in the top three thanks to its very attractive price. Using this insulation in an individual home provides the following advantages:

high degree of protection;
resistance to rotting and mold and mildew;
low degree of water absorption;
ease of installation and no need for complex tools and protective equipment;
the light weight of the material prevents excessive load on the structure and allows for insulation from below.

Extruded polystyrene foam

More often this material is called a shorter word - penoplex.
Being the closest relative of foam plastic, penoplex is devoid of most of its disadvantages. In the process of improving performance characteristics, the cost has increased. The material is produced fireproof, it has sufficient strength for use as a base for flooring and is light in weight for use in ceiling construction. Do-it-yourself installation is quite simple. This issue is discussed in detail in the article. The text discusses options for using both penoplex and polystyrene foam for different types of floor construction.

For people who decide to build their own wooden house, the naturalness of the materials is usually important. Here penoplex, like foam plastic, loses to other types of insulation due to its artificial origin.

Expanded clay or sawdust

If you decide to use completely natural materials in your home, these two types of insulation will become indispensable helpers. They do not have high heat-protective characteristics, like previous types, but provide reliable protection from the cold with a sufficient layer thickness. Sawdust can be obtained almost free of charge; expanded clay is also an inexpensive material.

Insulation of the attic floor can be carried out by non-professionals and does not require special skills. The application is limited by the physical characteristics of these materials: they cannot be used for thermal protection from below.

Heat protection foam

Polyurethane foam insulation is a fairly new material in construction. When constructing a building yourself, this method can provide high speed work and reliable protection from the cold. You can read about insulating a building, including attic floors, with foam in the article.

This provides a large selection of materials for insulation and significant savings on construction.

A large percentage of heat losses occur precisely through the ceiling of the upper floor, which is why it is so important to choose the right insulation and follow the installation technology. Are you insulating your house for winter and don’t know how to insulate the attic floor using wooden load-bearing beams? Having gained experience in this matter, I will accurately convey the technical aspects of thermal insulation, and also describe step by step the procedure for carrying out the work

Are you insulating your house for winter and don’t know how to insulate the attic floor using wooden load-bearing beams? Having gained experience in this matter, I will accurately convey the technical aspects of thermal insulation, and also describe step by step the procedure for carrying out the work.