When we discuss a set of roofing materials, one of the most common questions is “do you really need waterproofing?”.

When it comes to a residential attic, the situation is already clear: yes, waterproofing is definitely needed, and not just any kind of waterproofing, but a diffusion membrane.

And when it comes to a cold attic, one sometimes remembers the village grandfather / grandmother, and maybe the parental home. And it confuses things a bit.

Most of us come from the countryside, urban dwellers in several generations are actually a minority. Therefore, we all remember such houses. And these houses stood for many decades, many still stand. And there was no waterproofing there at all ...

Maybe she doesn’t need it, and people are reinsured for how much in vain ...

Is it that simple? Let's figure out how old village houses lived without waterproofing using a real example.

And let's take not the simplest case - a metal roof. Which, in addition to leaks, is also subject to condensation.

To do this, I climbed into the same grandmother's attic. First of all, I was convinced that the roof of the house, which had stood without a major overhaul for more than fifty years, is quite efficient and will stand for another “-twenty” years with proper care.

What is the secret of its longevity - even without waterproofing ...

1. Absorbent natural insulation.

In the attic there is a thick layer of absorbent material. In our case, a mixture of dry soil with pieces of bark and coniferous-deciduous litter. In different areas, the “recipes” for this backfill were different - depending on nature, traditions and local crafts. Only sawdust, clay with sawdust, various slags ... These backfills have in common that, firstly, they served as an affordable and inexpensive insulation, and secondly, they worked as an absorbent layer that could retain a fairly large amount of moisture inside - if suddenly the roof "dripped" with condensate or due to a leak.

Such a "diaper" did not allow moisture to the interior trim and floor beams.

Modern heaters, on the contrary, are made as hydrophobic as possible. This means that any significant leakage is likely to go immediately to the underlying layers.

2. Excellent attic ventilation.

Sewing gables - from a board with slots. Filing overhangs - from a board with slots. Roofs were usually made simple, architectural originality was not pursued. Our object, for example, is a simple "gable". As a result, even without special structures for air exchange, there are no problems with attic ventilation. Water vapor - whether hanging in the air in the form of fog, or evaporating from the insulation - quickly escapes with the movement of air.

Overhang filing (photo with flash and without)

Gable sewing (photo with flash and without)

Modern materials for finishing gables and filing overhangs, as a rule, have poor air permeability and do not provide a large amount of water vapor to the external environment. Air vents and other cold attic ventilation designs are designed not to dry out leaks and dripping condensate, but to release a relatively small amount of excess moisture. In addition, modern roofs come in very complex shapes - and in such cold attics, simple ventilation solutions will not be enough.

3. Simplicity and accessibility of monitoring and repair.

The attic in the village house, although it was non-residential, was almost always used for storing various things and for other household needs. Therefore, they constantly climbed it. As a result, the roof was always under surveillance. And it was easy to inspect the roofs - nothing was covered with trim or intermediate layers, everything was in plain sight. As a result, leaks were easily noticed and quickly fixed. Temporarily - with a substituted basin, and then - with local repairs. With repairs, everything is also easier than on modern houses - it is easy to get to any place and to any node, even from above, even from below.

The modern way of life rarely leaves time to regularly inspect the roof for any minor defects. Nowadays, a country house is created in order to build everything reliably for decades - and to do other, more pleasant things.

Do the examples of old village houses end up being an argument for not needing waterproofing? Probably not. Everything worked differently there.

Now - other materials, other standards of aesthetics and maintenance, otherwise the physics of the roofing system is built in modern houses.

We wish all parental homes that still serve faithfully, comfort and longevity.

And to everyone who builds new "family nests" - success in construction.

Useful materials

Vapor barrier of the attic floor of a cold attic protects wooden floor structures and insulation from steam entering them from the premises of the house. Steam condensing on the beams can contribute to the damage of wood by fungi and mold, thereby reducing the 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 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 losses 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 pass steam (only vapor barrier).
2. foil vapor barrier— does not pass steam and reflects thermal radiation (steam and thermal insulation). Such a vapor barrier is mounted with a foil side to the premises.

Vapor barrier of attic floors with foil materials due to its characteristics, it is the most preferred in 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 an attic staircase with an insulated hatch (Thermo). To exit from the attic to the roof, we recommend installing deaf or glazed exit hatches on the roof (Velux, Vilpe, etc.)
2. Para - or super-diffusion moisture-proof membrane - for effective removal of steam from a heater.
3. Insulation - mineral wool boards. The recommended thickness for the Moscow and Leningrad regions is 300mm. 200mm are laid in the interbeam space, the remaining 100mm are laid perpendicular to the laid layers - counter-warming. For comparison, building codes in Finland determine the thickness of the insulation from 400 to 500 mm. It is recommended to postpone the laying of the insulation as much as possible - not earlier than 6 months after the completion of the construction of the house box. Because for the construction of the floor, mainly a bar of natural moisture is used. The beam must dry properly, otherwise, there is a high probability of wood damage by fungi and mold, which entails additional costs for dismantling / installation work and wood treatment with bleaches and antiseptics.
4. Control grille and ventilated gap. For effective ventilation and removal of steam from the surface of the waterproof membrane.
5. Cover beams. As a rule, in private housing construction, a board 50x200mm or a bar of natural moisture 100x200mm is used.
6. Crate - the basis for laying insulation. As a crate, it is recommended to use a board 100x20 (25) mm and lay it in 70-80 mm increments. The resulting cracks will form an additional air thermal layer under the insulation. That. Insulation plates (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 punching 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 the insulation as much as possible (see above).
7. Attic vapor barrier on wooden beams- fastened with a construction stapler from below to the draft ceiling (batten), which allows you to cut off the pairs from the entire floor structure. It is necessary to overlap the vapor barrier rolls at least 15-20 cm and carefully glue them with aluminum adhesive tape. Be sure to form laps on the walls of 15-20 cm and carefully glue them (start under plaster and other wall decoration). Carefully seal the places where chimneys, ventilation pipes and other utilities pass through the attic floor using special sleeves. The best vapor barrier material is high-density polyethylene film from 200g/m² and above.
8. Close attic - finished ceiling is attached to the vapor barrier. On the crate, guides, the final ceiling is installed (OSB, drywall, etc.). For the best fire protection, it is recommended to "sew up" the ceiling with drywall sheets in 2 layers.

Vapor barrier of a cold attic floor (scheme):

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

When ensuring the insulation of a private house and the insulation of 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, in a temporarily unheated room, heat can escape through the space of a cold attic. Therefore, the issue of attic insulation must be addressed without delay.

1 Why is attic floor insulation necessary?

Insulation of the cold floor of the attic with stone or mineral wool, by and large, is necessary in little used premises, which are properly equipped with special roof ventilation.

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

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

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

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

The presented insulation is the most suitable for this type of work, it can also be used to insulate the floor surface in the living 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, then moisture rising from the floor of the house will lead to the formation of condensate.

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

1.1 Attic insulation requirements

The process of insulating the floor of the attic 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 size of heat loss, but also on the duration of the operational life of the entire truss structure and roofing.

The fact is that the water vapor inside the heated room diffuses to the attic of the house. In order for the applied insulation 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 moisture by vapors of ascending heated air using a special vapor-tight material.

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

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

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 the entire roofing pie increases. The thermal insulation performance of the structure is also reduced due to the fact that the tightness of the vapor barrier layer has been broken.

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

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

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

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

1.2 Features of insulation of beam ceilings

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

Insulation of the ceiling with mineral wool from the side of the attic

The lower part of the ceiling is sewn up with 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, a subfloor covering is laid. It can be a tongue-and-groove board, plywood sheet or OSB board. Mineral wool is adjusted to a special vapor barrier prepared in advance.

An alternative to it can serve as an ordinary film made using 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 desired thickness parameters. The surface of the beams must be equipped with an additional insulating layer.

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

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

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

2 Why is mineral wool used for attic insulation?

In most cases, when insulating attic floors, the choice of the consumer falls on mineral wool. Its advantage lies in the fact that its installation does not require special skills.

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

Attic insulation with mineral wool

High soundproofing 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. Mineral wool is presented in three varieties, it can be basalt glass and stone.

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

This may be a carbonate-type rock, which regulates the level of acidity of the substance, which entails an increase in the service 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

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

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

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

The process of warming attic floors begins with the selection of the necessary tools and additional materials. 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 attic floors or beams.

To enhance the thermal insulation qualities, 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 roof space, he will collide with a layer of insulation. Due to the fact that mineral wool is generally recognized as a vapor-tight material, it will take all the outgoing moisture into itself.

If it is left without the necessary access of air and sunlight, it will gradually shrink and, in the end, will lose all its heat-insulating qualities.

Attic cold interfloor overlapping 20 cm min.

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 thermal insulation thickness parameter directly depends on the climatic conditions in the region.

Insulation of the ceiling of a cold attic with mineral wool

Warming the ceiling of a cold attic with mineral wool - advantages. Features of warming the 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 attic construction. The air temperature of such a room, as a rule, is slightly higher (by no more than 4 degrees) than that of the air outside.

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

• roofing;
• external attic walls;
• insulated ceiling between the attic and the living space below it.

It should be noted that the insulation of the ceiling of a 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 considered option has a number of advantages:

• reliability of waterproofing coating. It is achieved by reducing the number of superstructures protruding above the roof, which, as a rule, are its weakest points;
• ease of operation. The existing internal under-roofing space makes it easy to inspect and maintain all floor and roof structures;
• the overlap area is less than the area of ​​the pitched roof, respectively, the area of ​​​​possible heat loss is reduced;
• the presence of an additional operating room.

In order for the advantages of the cold attic design 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 of the cold attic.

Organization of ventilation

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

• removal of excess water vapor penetrating through the ceiling from below from the residential part of the building in order to prevent the appearance of condensate and moisture of the insulation and the roof truss system;
• creation of an optimal microclimate.
• Ventilation occurs due to two types of products:
• 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 ​​\u200b\u200bthe products should vary from 2 to 3.33 sq.m. This calculation is performed in accordance with the norms of SNiP, and it is quite simple to make it. It equally applies to various options for a roofing cake coated with metal tiles, corrugated board or soft tiles.

The basic rule for the location of the vents is as follows: the most efficient operation of the ventilation system is with the maximum removal 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 overhangs and along the entire length of the roof ridge.

Often, additional ventilation is performed through dormer windows installed on 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 non-ventilated areas, dormer windows should be located on opposite slopes.

Usually dormers are of three types:

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 ingress of birds, the air vents are equipped with protective nets or gratings, and blinds are installed on the dormers.

Thermal insulation options

The design of a 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 side of the attic;
• from the inside of the residential part of the building.

Thermal insulation from the attic

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

The sequence of work stages:

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

This node is one of the many possible ones that fulfill the basic requirements for warming the cold attic floor and allow you to get the following advantages:

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

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

Thermal insulation from inside the living room

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

• the ceiling level is lowered;
• 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 thermal insulation material and the finishing material.

The implementation of thermal insulation from the inside is quite 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 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 bars of the crate with additional fastening with dowels to the ceiling;
• gypsum board or stretch ceiling is attached as a finish to the suspended ceiling.

There are many other possible ways to insulate the ceiling, but with all the differences in the technologies and materials used, the basic principles should be consistent with those given above.

Conclusion

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

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

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

Source: www.hugebuilding.ru

Roof device with a cold attic

Most pitched roofs in our country have a cold attic in their design. This name is due to the air temperature in the attic, which should not differ much from the air temperature outside the house. With such an arrangement of the attic, a sufficiently large buffer air zone is formed, which allows you to effectively control the temperature in the attic with its proper arrangement.

Cold loft design

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. Building an attic will cost several times more and will require more labor costs.. Although, it is undeniable that the attic will significantly expand the living space.

Cold loft roofs have the following main ingredients in their pie:

1. roofing;
2. attic outer walls (applicable for gabled roofs with gables);
3. insulated ceiling between living space and attic.

Ventilation is provided by eaves and ridge ducts. The air passing through the cornice openings is called supply air, and the air exiting through the ridge is called exhaust air. Additionally, ventilation can be done through dormer windows on gables or roof slopes. Windows are equipped with louvered grilles for the possibility of adjusting the intensity of ventilation.

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

Dormer windows 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 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, it is most important to minimize heat loss through the attic floor. For both wooden and reinforced concrete floors, vapor barrier is mandatory. It is laid on the ceiling itself and protects the insulation from vapors that can condense in the heat insulator, passing through the ceiling of the living space. As a heater, plate and bulk materials can be used. The ceiling pie consists of a vapor barrier, floor beams and insulation.

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

• polystyrene and foam boards;
• mineral wool boards 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 calculated winter temperature using the table below.

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

Insulation is placed between the joists or beams of the ceiling, and a plank flooring is made on top for attic passages. Logs are usually 50 mm thick, and deck 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, and someone categorically recommends abandoning it. Much here depends on the type of roofing material and the angle of inclination of the roof slopes.

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

For flat 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, having overpaid a little, you will receive additional protection against moisture ingress on the insulation in the ceiling of a cold attic.

Possible leaks or condensate when it gets into hydrophobic heaters significantly reduce their heat-insulating 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 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 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 of the crate of a cold attic is no different from insulated roofs. The dimensions of the crate and its pitch determine the type of roofing to be installed.

Temperature regime of a cold attic

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

You can evaluate the effectiveness of a heat insulator using a temperature measurement of the top layer of insulation. An electronic thermometer is immersed in a heater by 10-20 mm.

As you can see, the arrangement of a cold attic pie does not differ in particular constructive complexity. The main task is to provide the necessary intensity of ventilation and the thickness of the heat-insulating layer in the ceiling ceiling.

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

The device and design of the cold attic pie. Vapor barrier ceiling and waterproofing in a cold attic. The optimal 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 heaters need to be protected from the penetration of atmospheric water from the outside and household fumes from the inside. The vapor barrier device cannot be neglected, because this component of the insulation system plays no less a role than waterproofing. It is especially important to know how a vapor barrier is constructed for a ceiling in a wooden floor, since materials that are extremely sensitive to excess water are used in its construction.

The role of vapor barrier in construction

However, if during the construction of a house with insulation systems violations of technological rules were made, water will begin to linger in the building envelope. At best, the result will be increased heat loss, a feeling of perpetual cold and dampness. At worst, destruction or damage to structures is coming, dictating a mandatory overhaul.

Steam protection attic

According to the requirements of building codes in winter, the temperature within the cold attic should not exceed that outside by more than 5 - 6º C. The rules outlined in SP 17.13330.2011 state that in order to equalize the temperature and humidity parameters inside and outside the attic, it is necessary to arrange a natural type of ventilation.

The specifics of the vapor barrier device

• glassine

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

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

Source: krovgid.com

Attic insulation 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 beams of the floor. If the attic is provided heating system and people will live there, then the insulation is laid 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 acrylic-based materials.

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 suited for attic insulation with mineral wool than stone wool. The latter is too brittle, and it has considerable weight.

As you already understood, the insulation of the cold attic of a private house with mineral wool is carried out by laying thermal insulation between the supporting beams directly on the draft ceiling of the first floor. Due to the high hygroscopicity of mineral wool, a vapor barrier film must be used. In principle, even plain polyethylene can be used. There will be no special loads on the film 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.

Attic insulation with mineral wool, technology:

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

The vapor barrier tapes must overlap, the joints are glued with double-sided tape. Mineral wool is placed at random so that there are no cold bridges at the junction of the insulation to the beams.

Insulation of a cold attic with mineral wool is always preceded by a calculation of the thickness of the thermal insulation. In any case, the layer will be at least 10 cm. Mineral wool is produced with a thickness of 5 cm or more. It is better to lay the thermal insulation in two layers with offset 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 on top of the beams. It is advisable to close the insulation with waterproofing before this - a material that does not allow water to pass through, while passing steam, but only in one direction. It is important not to confuse which side to lay the waterproofing, 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 a country house. To do this, a heat exchanger is built in above the furnace.

Insulation of a heated attic with mineral wool

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

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

• vapor barrier - fastened with a stapler to the rafters. Fitted with overlap and stretch. Joints are sealed;
• mineral wool - placed by surprise. You can use glass wool of any configuration (mats, slabs, rolls) or basalt wool in slabs with a soft end;
• waterproofing - a three-layer polypropylene diffusion membrane. Tapes are laid horizontally and overlapped, starting from the edge of the roof;
• counter-lattice - the section of the bars depends on the length of the roof slopes;
• finish coating.

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 how to insulate 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 frame house thermal insulation. Also, the insulation is laid on the floor 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, it must pass from one surface to another and preferably without joints. If there is a junction, then the thermal insulation must be pressed tightly against each other.

With such an installation, no doubt, more material will go, but in the future there is a benefit. You do not have to heat the square meters that are not used 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 floor 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, as it does not break and, after compression, restores its previous shape. It is lightweight and does not overload the load-bearing floor beams and truss system. If you use stone wool, then you need to take plates with a soft end so that they can be inserted between the guides by surprise. A vapor barrier is laid between the heated room and the insulation. When laying thermal insulation on the roof, waterproofing is also needed, which is placed on the outside. There must be a ventilated gap between the waterproofing and the finish.

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

On the ceiling 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 condensate and further destruction, and also prevents the appearance of mold and mildew in the insulation boards.

Design device features

A 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 disturbed, which will lead to the formation of condensate on the roof.

The floor of the attic is the ceiling, which simultaneously serves as the ceiling of the living space. With a decrease in street temperatures, the overlap becomes prone to the appearance of condensate, the formation of which is due to the temperature difference in its lower and upper parts. In order to prevent droplets of condensate from penetrating 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, moist 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 any type of bases, including concrete and wooden floors. Isover plates, 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 vapor barrier the ceiling in a cold attic. Its disadvantage was a rather large weight and labor costs during installation. Today, the construction market offers a large selection of vapor barriers that differ in the form of release, 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 a membrane:

• 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 a warm climate, subject to moderate temperatures: under the influence of extreme influences, it quickly loses its performance properties and collapses. The disadvantages include the low strength of polyethylene, which can lead to material ruptures even at the laying stage. Often used as a vapor barrier, glassine is very similar in its properties to polyethylene: it also retains moisture well, but at the same time does not let air through at all.

• A more practical type of vapor barrier is polypropylene.. Such a film tolerates thermal shocks well and has high resistance 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 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 are membranes. The insulator is designed in such a way that the ability to pass steam is possible only in one direction. Due to this property, moisture is quickly removed, and air is exchanged between the ceiling and the attic. In the domestic construction market, the Isospan model is considered the most famous, the fleecy structure of which is able to retain condensate droplets and quickly evaporate them. The installation of a membrane coating involves the mandatory formation of a ventilation space designed to ensure that the liquid has 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. The isolant is a film coated 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 operation it is prone to the appearance of mold and fungus. The disadvantages include its low hygroscopic properties.

• Mylar coated kraft paper can withstand temperatures up to 140 degrees. This allows you to use it as a vapor barrier material in the construction of baths. The disadvantages include low resistance to the chemical composition of detergents.
• Foil fiberglass It 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 vapor barrier of the ceiling are represented by varnishes and mastics. The compositions are applied to the surface of the floor and after complete drying form a thin film that can retain moisture and pass air. This contributes to 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 areas and, if contacted, may be harmful to health, therefore, when using them, personal protective measures must be observed.

Compliance with simple laying rules and operating standards will significantly extend the life of the vapor barrier.

• The film material should be fixed with staples or small nails, placing a thin wooden rail under the fasteners. This will better press the material to the base and reduce the likelihood 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 in the presence of thermal insulation.
• During laying, it is recommended to carefully control the tension of the material: the film must be in a free position. This will avoid rupture of 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 sufficient to use a membrane or reinforced polypropylene film, and only foil vapor barriers should be used in the construction of baths.

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

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

For more information on ceiling vapor barrier, see below.

If an apartment or a private house has an unheated and, accordingly, a cold room above the ceiling, homeowners may encounter an unpleasant problem - condensation on the ceiling surface. To avoid this trouble, with a cold attic, a ceiling vapor barrier is essential. 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, it is a thin film through which water cannot penetrate. In a ceiling situation, it prevents the warm, moist air rising upwards from escaping from the room. To create a vapor barrier layer in different situations, you can use different materials:

• 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 insulation layer or settling on the cold surface of concrete floors. Other vapor barriers are able to pass some of the air through themselves, but retain moisture. Films with a layer of foil applied do not allow moist air masses to pass through themselves and have one more function - they reflect part of the heat back into the room.

Polyethylene and glassine

These insulating agents create a moisture-impervious barrier. However, they not only prevent water from entering the insulation layer or falling on cold floor structures, but also prevent air circulation. Therefore, in a room with polyethylene or glassine as insulation against moisture on the ceiling, it is necessary to equip a ventilation system for normal air exchange.

Such insulators do not have too many advantages, and if life 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

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 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 norm. At the same time, there are certain features of the installation of such membranes - a ventilation gap is necessary to remove moist air vapor. Therefore, the installation of a decorative ceiling covering from the side of the room is carried out on a crate or frame, which will create the necessary space for ventilation.

Liquid coatings

A fairly new solution, created thanks to the achievements of chemists. It looks like a normal 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 pass air, but prevent the passage of water vapor. Such materials are often used to vaporize the ceiling from the side of a cold attic.

In addition, it will be a very effective solution if flat roofing is being processed 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 areas. Be sure to familiarize yourself with the characteristics of the selected paintwork.

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

The vapor barrier device cannot be neglected, because this component of the insulation system plays no less a role than waterproofing. It is especially important to know how a vapor barrier is constructed for a ceiling in a wooden floor, since materials that are extremely sensitive to excess water are used in its construction.

The role of vapor barrier in construction

From the inside, building structures are constantly affected by steam flows emitted during compulsory household work, breathing of household members, taking hygiene procedures, etc. Penetration of water suspended in the air into enclosing and warming the house systems adversely affects their technical and operational properties.

On steam-moistened surfaces, colonies of fungi settle at a brisk pace, with surprising speed rendering almost all types of building materials unusable. Rotting and decaying wooden elements. Wet insulation loses about half of its insulating qualities, because. the water contained in it significantly increases the thermal conductivity.

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

The predominant volume of evaporation, according to its own physical nature, is directed upwards in order to "exit" into the atmosphere through the enclosing systems. The air currents that include steam most actively “attack” the ceiling, the upper segment of the walls and the roof structure. They need to be strongly protected from the penetration of water in the air.

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

However, if during the construction of a house with insulation systems violations of technological rules were made, water will begin to linger in the building envelope. At best, the result will be increased heat loss, a feeling of perpetual cold and dampness. At worst, destruction or damage to structures is coming, dictating a mandatory overhaul.

Steam protection attic

The function of the vapor barrier film in the thermal insulation cake is to prevent the penetration of airborne water into building structures. This means that it is the vapor barrier that must stop the evaporation, so as not to let through at all, or to reduce to the minimum values ​​\u200b\u200bwhat managed to pass through it.

We have already found out that in our regions, steam, along with the air flow, most often moves out of buildings. Only in the summer heat is reverse current possible. The vapor barrier layer should be the first in the path of moist air. Therefore, it is laid from the side of the operated premises in front of thermal insulation.

A vapor barrier on the ceiling is carried out if it is not intended 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.

True, it is still necessary to protect the materials of the cladding of the slopes and the truss frame. From external influences, waterproofing is installed, from the formation of condensate, which occurs due to the difference in temperatures inside and outside the structure, a ventilation system is arranged.

According to the requirements of building codes in winter, the temperature within the cold attic should not exceed that outside by more than 5 - 6º C. The rules outlined in SP 17.13330.2011 state that in order to equalize the temperature and humidity parameters inside and outside the attic, it is necessary to arrange a natural type of ventilation.

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

The specifics of the vapor barrier device

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

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

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

Therefore, materials with a vapor permeability close to zero or equal to fractions of one are generally selected for the vapor barrier device. 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.

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

• Vapor barrier. Layer made with 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 rails.
• Thermal insulation. A layer performed by backfill, roll or slab 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 operation of the attic is not expected, then the thermal insulation is laid without waterproofing and wind protection.
• Waterproofing. A layer made of a diffusion membrane or perforated polyethylene. It is arranged only in the case of attic operation, it is laid under the flooring or flooring.

If the use of the attic is not planned, then there is no need for a waterproofing device on top of the insulation layer. It is transferred to the slopes, where it does the job of protecting the entire roofing system from atmospheric water. The insulation layer over the ceiling also does not need wind protection, because. the enclosing structure itself protects from blowing heat out of its thickness.

To maintain the roofing system, ladders are installed within the unused attic. They are laid directly on the logs if slab or roll material is used. Ladders are installed on legs if the insulation was formed by filling expanded clay. Insulators loosely laid in the attic need to be “loosened” periodically so that the insulating 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 peculiar bumpers entering the walls. Those. so that this barrier is not only between the ceiling and thermal insulation, but also between the insulation and the parts of the walls in contact with it. Each beam or wall of the shields must cover the protective material.

Laying vapor barrier material on the floor is made:

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

Regardless of the scheme of the floor device, the vapor barrier for the ceiling under the attic in a wooden house should form a solid carpet that does not let water through or conducts it in a minimal amount. For this, the panels of the rolled material are laid with the overlap indicated by the manufacturer, the size of which is indicated in the instructions, and glued together with one- or two-sided adhesive tape.

The vapor barrier material should be rolled out over the ceiling in the same way as it was wound by the manufacturer. You don't need to flip or rewind anything. In order not to confuse the laying sides, the side in contact with the overlap is designated by the manufacturer.

How to choose the right material

It is important not only to lay the vapor barrier correctly, but also to choose the most suitable material for its construction. Tandem vapor barrier - insulation must work perfectly, preventing the possibility of wetting the heat-insulating cake.

The oldest version of the steam protection device is greasy clay, which was used to process the ceiling from below or above. Paired with clay, a dry soil-vegetative layer was used, which prevents the penetration of hot air in hot weather and cold air in cold weather. Instead of earth, fine peat, shavings, sawdust, dry leaves and similar materials can be used.

Instead of obsolete insulation varieties, materials are now used that are specifically designed to protect against steam and heat leaks. Their laying is much easier and significantly 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, the following are now used:

• glassine. A budget option with a vapor permeability of about 70 mg / m² per day. It is mainly used in domestic buildings that do not require an increase in humidity levels above standard values.
• Polypropylene and polyethylene films. Vapor permeability is calculated in units, approximately 3 - 5 mg / m² per day. For the most part, these are reinforced materials that are resistant to temperature extremes, mechanical stress and UV radiation. Suitable for arranging wooden floors for backfill insulation.
• Foil-clad vapor barrier membranes. 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 ability to pass steam varies over a wide range from 3 to 15 or several tens of mg/m². These are the newest varieties of universal purpose. In an exploited attic floor, they can be installed on the lower and upper sides of the thermal insulation.

Anti-condensate varieties are available 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, it prevents the penetration of moisture from the outside.

Video about the rules of the vapor barrier device

An example of laying 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:

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

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.

Description

The device of a cold attic is the simplest solution in terms of technology, especially when compared with an alternative warm option or attic construction. The air temperature of such a room, as a rule, is slightly higher (by no more than 4 degrees) than that of the air outside.

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

• roofing;
• external attic walls;
• insulated ceiling between the attic and the living space below it.

It should be noted that the insulation of the ceiling of a 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 considered option has a number of advantages:

• reliability of waterproofing coating. It is achieved by reducing the number of superstructures protruding above the roof, which, as a rule, are its weakest points;
• ease of operation. The existing internal under-roofing space makes it easy to inspect and maintain all floor and roof structures;
• the overlap area is less than the area of ​​the pitched roof, respectively, the area of ​​​​possible heat loss is reduced;
• the presence of an additional operating room.

In order for the advantages of the cold attic design 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 of the cold attic.

Organization of ventilation

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

• removal of excess water vapor penetrating through the ceiling from below from the residential part of the building in order to prevent the appearance of condensate and moisture of the insulation and the roof truss system;
• creation of an optimal microclimate.
• Ventilation occurs due to two types of products:
• 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 ​​\u200b\u200bthe products should vary from 2 to 3.33 sq.m. This calculation is performed in accordance with the norms of SNiP, and it is quite simple to make it. It equally applies to various options for a roofing cake coated with metal tiles, corrugated board or soft tiles.

The basic rule for the location of the vents is as follows: the most efficient operation of the ventilation system is with the maximum removal 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 overhangs and along the entire length of the roof ridge.

Often, additional ventilation is performed through dormer windows installed on 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 non-ventilated areas, dormer windows should be located on opposite slopes.

Usually dormers 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 ingress of birds, the air vents are equipped with protective nets or gratings, and blinds are installed on the dormers.

Thermal insulation options

The design of a 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 side of the attic;
• from the inside of the residential part of the building.

Thermal insulation from the attic

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

The sequence of work stages:

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

This node is one of the many possible ones that fulfill the basic requirements for warming the cold attic floor and allow you to get the following advantages:

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

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

Thermal insulation from inside the living room

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

• the ceiling level is lowered;
• 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 thermal insulation material and the finishing material.

The implementation of thermal insulation from the inside is quite 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 foam):

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

There are many other possible ways to insulate the ceiling, but with all the differences in the technologies and materials used, the basic principles should be consistent with those given above.

Conclusion

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

Vapor barrier of the ceiling of the last floor is an obligatory part of the complex work on the insulation of the cold attic ceiling. For concrete bases, it is enough to seal the seams hermetically, lay a vapor-proof film on top of the slabs in a continuous layer, then a heater and a waterproofing membrane. Vapor barrier and insulation of wooden floors are done differently.

What is vapor barrier for?

Perform the following functions:

• protect the insulation from moisture vapor entering it together with warm air from the heated room;
• prevent the creation of conditions for the wetting of structural 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" must meet the requirements of SP 23-101-2004, which regulates the design standards for thermal protection.

According to clause 8.5 of the general provisions, technical solutions must ensure reliable waterproofing of heat-insulating materials and 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 draft ceiling boards stuffed from the side of the room. Such a device determines the specifics of the sequence of layers. If on a 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 the wooden structural elements.

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

1. They equip the ceiling - a draft ceiling is hemmed to the beams (number 8 in the diagram).
2. From the side of the room, the hemmed 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 barrier, then the anti-condensate rough surface or the metallized layer should face the inside of the room.
3. The overlap between the panels, regardless of the laying direction, is 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-proof tape.
6. A gap is required between materials with an anti-condensation or reflective surface and a fine finish of the ceiling. It is provided by stuffing rails with a thickness of 4 - 5 cm.

deposit photos

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

Mineral wool is laid between the beams on the surface of the false ceiling (in soft mats or in rolls). 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 the insulation is required along the perimeter of the cold attic to a width of 1 m or more. In private houses, with a relatively small building area, they do it simply - with a high vapor permeability (superdiffusion) ability, they are 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. Attached to the floor beams and around the perimeter. The overlap between the panels is 15 - 20 cm.

Counter rails 4-5 cm thick are stuffed along the beams (number 3 in the diagram), which provides a ventilation mode for the heat-insulating layer.

The floor is laid along the counter-rails.

What you need to know so that it does not drip from the ceiling

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

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

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