The popularity of attics is growing rapidly. For developers, this type of housing seems to be less expensive in comparison with the cost of equipping storey premises. In addition, many homeowners are attracted by the opportunity to implement specific architectural and design solutions, substantively developed by European experts. Why has the transfer of under-roofing zones into the housing stock been updated only in the last 10-15 years? The answer lies in the climatic difference between continental Europe and the European part of the Russian Federation. Only modern technologies in the field of insulating materials, they make it possible to choose insulation for the attic, which provides a comfortable microclimate in a "house without walls" located somewhere in the Moscow region.
It is important to choose the right insulation for the roof space
Arrangement of attic roofs is functionally and technologically different from work carried out on the main floors and in unheated attic spaces... Insulation of the attic is associated with an increased complexity of installation processes, the need for a thermophysical calculation, as well as the importance of competent development of ventilation and vapor protection.
In non-residential attic spaces, thermal insulation is placed in the niches between the ceiling beams. The roof structure in this case plays the role of a barrier that protects the building from wind load, thermal expansion and precipitation. Insulation for mansard roofon the contrary, it is part of a roofing sandwich designed to perform all the functions inherent in walls, ceiling and roof at once.
More moisture enters the attic than in the storey premises. Water in the form of rising vapors penetrates from below. The vapor barrier of the floor slab reduces the moisture intake, but does not reset it.
The second factor of air humidification is associated with the inevitable condensation on the underside of a tile or other roofing material... Moreover, the amount of this condensate on insulated roofs is greater than on cold ones due to the increased temperature gradient. In addition, the ventilated cold loft forms a buffer air cushion that effectively dries out the roof from below. The absence of such a buffer in the attics reduces the natural ventilation of wooden rafters and the insulation itself.
The location of the insulation directly under the roof slopes increases the rate of heat transfer, therefore the insulation for the attic should be more energy efficient than the insulation of the floor between the dwelling and the cold attic.
Insulation material selection criteria
What is the best way to insulate the attic? The study of the properties of heat insulators cannot give a substantiated answer to this question. It is necessary to correlate the characteristics of materials with their working conditions. The specificity of attics is expressed in three main rules for their insulation:
- Terms of performance of thermal insulation works. Usually fresh sawn wood is used for rafters. In this case, it is required to withstand at least six months before the insulation is carried out with materials with high vapor permeability.
Even when using dried wood, a pause of at least 2 weeks is required after installing the roofing.
- The choice of the thickness of the insulation. The intensity of heat flows through the roof is much greater than the loss of energy through walls or foundations. The usual thickness of mineral wool of 100 - 150 mm does not solve problems for attic insulation, even in the southern regions of Russia. It is necessary to use special calculator programs, where climatic conditions, dimensions building structures and materials of all sandwich layers. In temperate continental climates, the required design thickness of an insulator for a mansard roof is almost never less than 300 mm.
- Design of roof beams.
The height of the lumber profile should be 30 - 40 mm higher than the thickness of the thermal insulation layer. In this case, a sufficient ventilation gap is formed between the waterproofing and the insulation.
If work is underway to transfer the cold attic to the housing stock, then an additional lathing is usually used at the bottom of the rafters, which increases the mounting height to accommodate the insulation layer.
To determine which insulation is best for your attic roof, make a comparative assessment of the materials, taking into account the three rules outlined in the following order:
- Eliminate options that do not meet your fire safety requirements.
- Exclude options with a high vapor permeability of the insulation if you do not have time to dry the rafters.
- Calculate the required insulation layer thickness for several options.
- Make budget options. In this case, the exclusion of a vapor barrier membrane from the composition of the sandwich should be taken into account in the case of using insulating materials with a hygroscopicity close to zero.
Types of insulating materials used for insulating mansard roofs
First of all, it should be noted that insulating inclined surfaces with bulk materials is not only inconvenient, but also impractical, since the fragments rolling downward will block the ventilation gap. Therefore, sawdust, fluff pulp, expanded clay and similar heaters should be discarded. On the other hand, it is permissible to carry out insulation with plates obtained as a result of a mixture of the listed materials with clay or cement. However, the weight of such slabs should be taken into account in the calculation of roof trusses.
Fireproof heaters
The only relatively inexpensive fireproof heat insulator is mineral (basalt) wool. It is for this reason that it has long been the most popular option for use in attic sandwiches. How to choose a good mineral wool insulation for the attic? Will the regular roll-up isover that we use for walls work? Such material will work well, but ... not for long. The reason for this is the high capillary activity. Therefore, it is necessary to choose materials with special impregnations that reduce hygroscopicity: mineral wool ROCKMIN PLUS, Isover Pitched Roof and other brands, the names of which have a direct indication of the scope of application suitable for us.
Mixtures of insulating backfills with clay are also fireproof. The main problem clay insulation is a very large thickness of the insulating layer and its excessive weight.
Of the most modern developments, PIR slabs lined with heat-reflecting foil should be distinguished. They do not support combustion and have a record low thermal conductivity (0.024 W / m * K).
Heaters with the highest energy efficiency
Manufacturers of building thermal insulation have developed brands of extruded polystyrene foam (EPS) plates, specially designed for the arrangement of attics and roofs of cold attics. These are Penoplex Pitched Roof, TechnoNIKOL Carbon Solid and other materials with a thermal conductivity coefficient not higher than 0.030 - 0.034 W / m * K. The brands are distinguished by the possibility of ordering panels of increased length (up to 4.5 m), which significantly speeds up installation work.
EPS is a combustible material, but building codes allow its use in attics equipment. To increase fire safety, infrared screens with a foil layer should be used. Despite the fact that their vapor barrier function is not needed by EPS, the foil can significantly increase the resistance of the sandwich to fire.
On average, expanded polystyrene boards allow to reduce the thickness of the attic insulation layer by 20% in comparison with mineral wool. Spray polyurethane foam (PUF) and the aforementioned PIR boards are the champions in heat conservation. Due to the high toxicity of gases emitted during the temperature destruction of polyurethane foam, this material is not recommended for use in the equipment of residential attics. PIR boards are free from this drawback and are able to replace mineral wool with a 1.5-fold decrease in layer thickness.
Heaters with high specific noise absorption
Warming Zhivoizol - linen heat insulator
The soundproofing properties of mansard roof insulation can be very relevant when using metal tiles that enhance the noise of natural precipitation. Currently developed slab materials, characterized by a high coefficient of noise reduction with a small loss to mineral wool in energy efficiency. Among such developments, it should be noted pressed linen insulation known under the market brands "Termolen" and "ZhivaIzol". Slabs made of this material absorb noise in all frequency spectra by 20% - 30% more efficiently than mineral wool and EPS.
Conclusion
The choice of insulation for the attic roof should be carried out in parallel with the development of roof trusses and the construction of the entire sandwich, including roof cladding, membranes and battens. When transferring cold attics to housing stock, it is important to minimize the thickness of the insulating layer and use insulators with the lowest thermal conductivity coefficient.
The wrong choice of insulation, or its insufficient thickness, leads not only to cold in attic room... Even if you compensate for the low temperature with intensive heating, you may encounter:
- increased roof icing;
- a decrease in the service life of the roofing;
- failure of the drainage system.
Thus, competent design of a roofing sandwich for attics is important not only to provide comfort to residents, but also from the point of view of increasing the building resource.
The operation of attic rooms directly depends on the quality of their construction. Their peculiarity is that they do not have thick walls, their functions are performed by roof slopes. Therefore, temperature changes are felt in them more than in the whole house - they cool and heat up faster.
The situation can be improved by arranging the insulation layer. In the case of correct and high-quality performance, which is not observed sudden temperature changes during the day and over the seasons.
Thus, the thermal insulation layer makes it possible to make the microclimate of the attic room favorable, leveling the temperature in it.
When insulating a mansard roof, they resort to the same principles as when insulating ordinary roofs.
Thermal insulation scheme for the roof of the attic from the inside
The technology of insulating the attic roof involves the creation of a kind of multi-layer cake, each layer of which performs a specific function and complements the functional characteristics of other layers.
The mansard pie, when moving from inside the room to the outside, has the following structure:
You should not violate the sequence of the arrangement of the layers, as well as their presence. Most significant impact on comfortable living in attic floor influences the ventilation gap and thermal insulation. There are special requirements for their quality.
Features of roof ventilation attic type
High-quality roof ventilation system equipment will effectively resist the worst enemy of any building - condensation. Construction errors turn into both material costs for their elimination, and health disorders of the nervous system.
There are two ways of getting moisture into the house:
- external;
- interior.
With the first, everything is more or less clear. The second is associated with the fumes generated as a result of vital activity. Microscopic particles of moisture lead to the destruction of metal fasteners and insulation, rotting of the rafter system and, ultimately, the destruction of the house.
To avoid negative consequences, various systems for removing condensate moisture are created. The most optimal and effective is a combination of several methods.
Increased requirements for ventilation characteristics are imposed for attic (mansard) rooms, as well as houses covered with a soft roof.
The mechanism of condensation formation is based on the gradient (difference) between external and internal temperatures. To reduce it, it is imperative to create a free air space that ensures unimpeded air movement.
However, such spaces cannot always be created. Therefore, a ventilation and evaporation system is designed for mansard roofs. It is located in the attic pie - ventilation gap.
The choice of insulation
What kind of insulation to choose and buy? The most important component of the mansard pie is the thermal insulation layer. It is its quality that will determine the functionality of the room.
The type of insulation depends on the needs of the building, which in turn are determined by several factors:
They must be taken into account when choosing a heater. So, a thin insulation is not suitable for areas with low temperatures, but for warm regions it is acceptable. As a rule, for insulation of attics, they resort to roll or slab insulation and practically do not use backfill.
What should be the insulation?
Attic insulation must meet the following criteria:
- the material used should not give in to crushing and cracking. Its general properties should not change even in the most severe frosts, and should also remain unchanged after passing through a full freeze-thaw cycle;
- accumulation of moisture in the thermal insulation material is unacceptable... Otherwise, its insulating properties decrease, weight increases and loads on the entire roofing structure increase;
- the material must have low flammability indicators. Despite the fact that such materials are practically non-flammable, they are capable of under the influence high temperatures or open fire to melt. In this case, an important property of the insulating material is the absence of toxic substances in its composition. It must contain fire retardants - substances that slow down the spread of flame;
- maintaining its original shape throughout the entire operational period. This property is influenced by the resistance to cracks, cavities and other defects.
Types of insulation for attics: making the right choice
The modern construction market is saturated with a variety of insulation materials.
Along with the traditional ones, it also contains innovative thermal insulators:
- mineral wool;
- expanded polystyrene plates;
- liquid polyurethane;
- ecowool, etc.
Each of them has its own advantages. In order to correctly determine the insulation, it is necessary to get acquainted with its operational characteristics, talk with construction specialists, that is, it is possible to get large quantity information.
Commitment to sustainability makes more and more popular ecowool, which is a product of cellulose processing with the addition of antiseptics and fire retardants. Its low cost also attracts.
How to properly lay and protect the insulation from moisture?
Regardless of the type of roof, the insulation must be laid in the same way in the space between the rafters. When laying, it is not allowed to create a gap between the insulation and the rafters.
Thermal insulation should be 1/3 of the thickness of the rafter system.
When using thin insulation, multilayer styling is allowed. The insulation is fastened with staples.
A vapor barrier is used to protect the insulation from moisture.
It can be:
- film with mesh;
- polyethylene film;
- perforated film;
- fabric film.
If the attic is damp, it is better to use foil films.
- Use thermal insulation of the required density that retains its shape well.
- You should not use solid insulation materials, since they do not give tight joints. In these cases, polyurethane foam is not a way out.
- The use of waterproofing is mandatory.
- The prevention of the appearance of cold bridges is ensured by shifting the plates by ½ the length.
- Crevices should be avoided.
- Stop choosing the thickest insulation. So, if it is necessary to fill with 200 mm insulation, two 100 mm boards should be used, but not 4 50 mm boards.
- Follow the manufacturer's recommendations when performing installation work.
How to insulate with mineral wool?
Thermal insulation with mineral or basalt wool is carried out in several stages:
- cleaning surfaces from debris and dirt;
- installation of guide profiles. It is fixed at 60 cm height;
- special mineral glue; fixing the boards with construction fungi or dowels;
- reinforcement of fixed plates with special glue.
Insulation installation technology
Roof insulation begins with planning and performing preparatory work: 
- installation of windows;
- conducting communications;
- internal insulation of the roof structure.
The right step is work planning, which allows you to highlight the main stages and sequence of installation, as well as the acquisition of the required amount of building materials.
The next step is performed if necessary and consists in eliminating roofing defects.
- creation of a waterproofing layer. If traditional membrane materials are used, a ventilation gap must be created. Bars are attached to the top of the rafters;
- laying insulation material in the space between the rafters;
- fastening of waterproofing can be done with nails or staples.
When insulating with mineral wool blocks, they are placed in such a way that the length of the block is 2 - 3 cm longer than the rafter distance.
Soundproofing
The attic space can be divided by partitions into several rooms... In addition to all other work, soundproofing measures must be performed to make these premises comfortable for living.
Sound insulation of the under-roof space is provided by thermal insulation materials, since along with heat, they also have sound insulation properties. Technical specifications each of these materials contains sound insulation indicators.
As the thickness of the insulator increases, the quality of sound absorption increases. So, the use of 200 mm mineral wool insulation allows you to qualitatively isolate noise. Materials with a sound absorption coefficient of less than 0.6 should not be used. This is, for example, foam.
Window
Windows, vertical or inclined, installed in the roof slope are called dormers. They provide a large amount of light and fresh air in the room.
Modern windows for under-roof premises are characterized by high rates of thermal insulation and sound absorption. They can be remotely or electronically controlled.
Ventilation system
The roof ventilation system removes excess moisture from the entire roof structure. Thanks to the counter grill, a ventilation gap is created to ensure air circulation.
When the system is installed correctly, the ventilation ducts allow moist air to escape to the outside through the ventilation ridge or aerators.
Arrangement of the ventilation system involves air inflow either through the gutter or next to the eaves, the outflow of air should occur in the area of \u200b\u200bthe highest point of the roof.
When creating this system, you cannot do without additional capital investments, however, they are justified and will quickly pay for themselves, providing effective condensate drainage.
Attic vapor barrier
To protect the thermal insulation layer, special vapor barrier materials are used, which is a film.
It is applied to the inner side of the insulation (a 10 cm overlap is required both horizontally and vertically). All joints are sealed with a connecting tape.
The vapor barrier is also attached to rafter system... A prerequisite for laying this layer is to create a small gap with the help of strips.
Attics are wooden structures made of partition walls adjacent to the roof beams. Since the roof is made using pitched technology, an impressive space is formed under it, from which a living space can be made. The attic material, like the roof, does not have proper thermal insulation. It is also characterized by constant blowing, drafts. To make the room cozy and comfortable living in it, it is necessary to purchase insulation for the attic and perform a number of works on sheathing the attic.
Thanks to thermal insulation, it is possible to maintain a normal temperature for housing. Some materials can also provide sound insulation. By constructively improving the attic with the help of insulation, you can kill two birds with one stone. But which insulation is better for the attic? First of all, you need to understand the characteristics that a heat insulator should have, and then choose the most optimal one.
Requirements for insulation for the attic
The key criteria for choosing a material are its cost, durability and thermal insulation properties. Good insulation must have the following qualities:
- resistance to moisture;
- frost resistance;
- minimal hygroscopicity (the ability of the material to accumulate liquid in the structure);
- ecological cleanliness;
- lack of unpleasant odor;
- fire safety;
- water resistance;
- minimal deformability;
- thermal conductivity coefficient up to 0.04 W / m ° С.
It is hardly possible to find a material that would 100% meet the above requirements. Nevertheless, in the construction of private houses, a number of insulation materials are used that perfectly perform heat and sound insulation functions. These are:
- mineral wool;
- expanded polystyrene (aka polystyrene);
- foam materials (e.g. polyurethane foam);
- heaters made of natural fibers.
In addition to their structure, materials differ in price and complexity of handling. Further, each type of insulation is considered in detail.
Mineral wool
Outwardly reminiscent of the usual, mineral wool is made from different breeds, and is produced in the form of hard plates or mats (soft cloths). There are three groups of insulation in terms of composition:
- basalt (stone);
- glass wool;
- slag.
Basalt insulation is made from rocks of the gabbro-basalt group or marls (sedimentary rock of clay-carbonate structure). For comparison: gabbro-diabase is often used in sauna stovesbecause it retains heat perfectly and heats up quickly. The stone insulation has a vapor permeability of about 0.3 mg / m h Pa, and the thermal conductivity is about 0.035-0.04 W / m ° C. Fiber basalt wool do not prick, which makes it easier to cover the attic from the inside.
Glass wool is 1/5 of a mixture of soda, borax, limestone, sand, the rest is broken glass. The material is stronger, heavier than the basalt analogue, and also has greater elasticity. Withstands temperature fluctuations from -60 to +450 ° C without problems.
The slag material has the same length and thickness as basalt, but slightly less thermal conductivity. The fibers are quite sharp; this complicates the cladding from the inside of the room. Also has a high hygroscopicity. These shortcomings made the material the least demanded among representatives of mineral wool.
Each of the three types of material is an excellent sound insulator - insulation in the form of slabs belongs to class "A" for absorbing external noise, and mats - to group "B". It is often used as a fire barrier (not only in attics), since it has zero fire hazard (the most reliable group). Mineral wool is resistant to ultraviolet radiation, safe for humans, not afraid of pests (rodents or insects), does not reduce its effectiveness under the influence of aggressive chemicals. Nevertheless, the insulation is not without the following disadvantages:
- hygroscopicity is higher than desired (it forces additional layers to be laid when cladding from the inside - steam and waterproofing);
- irritates the skin (only need to work in long-sleeved clothing and wear gloves);
- profusely dusty (a respirator is also desirable);
- stands above other materials with similar properties.
There are negative sides, however, in demand, mineral wool is inferior only to expanded polystyrene, better known by a different name.
Styrofoam
The extruded material optimally combines the required parameters of an ideal insulation, being the most popular among consumers. The key advantage of expanded polystyrene is its low thermal conductivity, usually 0.03 W / m ° C. At least because of this indicator, insulation is preferable to mineral wool.
If the numbers don't tell you anything, it's worth turning to the practical side. When sheathing the attic from the inside, to achieve the same temperature in the room, a much smaller volume of foam is required than cotton wool. This achieves space savings and optimal resource consumption.
The practically zero hygroscopicity of the foam extends the life of the insulation layer. Water does not flow inside; this eliminates the possibility of mold and premature deterioration. Also, when using foam, the load on the roof will be minimal. By the way, not only because of its good hygroscopicity.
1 m3 of foam plastic weighs an order of magnitude less than a similar volume of mineral wool. Therefore, it is easier to work with it, and the load on the load-bearing roof beams does not increase regardless of the season.
Polyfoam for cladding the attic or other premises of a private house is mainly made in the form of plates, which save time when fastening. You can completely insulate the attic with polystyrene foam alone.
Ease of use is remarkable for the following material, which, when solidified, resembles foam, but is supplied in liquid form.
Polyurethane foam
PPU is one of the highest quality roof insulation materials. This is achieved by the fact that it is applied to vertical and inclined surfaces from the inside in a liquid form, and when solidified, it slightly increases in volume, effectively filling cracks or holes.
Low weight, low coefficient of thermal conductivity comparable to foam, resistance to extreme temperatures and other advantages put polyurethane foam in a row with mineral wool and expanded polystyrene. The fact that polyurethane foam is difficult to apply to the inner sloped surface of the roof is just a delusion. Good material adhesion prevents complications.
After curing, polyurethane foam acquires a single structure (like foam), which does not allow moisture or steam to pass through. This eliminates the need for additional vapor and waterproofing. However, there is one caveat - the cost.
The work of insulating the attic roof from the inside of the PPU requires special equipment... Most of the offices providing interior cladding services require 300-400 rubles (from 1 m2) for applying foam. It is not difficult to calculate how many extra thousand rubles you can give to specialists.
Polyurethane foam is applied in a small layer with a thickness of 4 to 10 cm. This is enough, since the thermal conductivity is 1.5-2 times better than rolled materials.
If the user has large amounts of money to insulate the attic from the inside, the PPU will become the best option purchases. Once having completed the work on applying the material to the inside of the roof, you can hope for 30-35 years of a comfortable indoor temperature.
Natural fiber materials
In Central and Eastern Europe, insulation made of flax, wood, hemp, fastened together with starch or polyester, has become widespread. There are products based on wood sawdust or seaweed. They are good, but not applicable for the attic, because they take up a large volume. Russia learned about such heaters about a dozen years ago.
Natural materials have a capillary structure that allows vapors or air masses to pass through. Their advantages include:
- safety for humans;
- fire resistance;
- the characteristics of noise and heat insulation are close to the properties of polyurethane foam, foam, mineral wool;
- do not generate dust and do not prick when lining from the inside;
- self-regulation of the indoor climate;
- no shrinkage;
- long service life (more than half a century);
- no need for special clothing when working.
Examples of natural insulation - Ecowool, Ecolin, cotton fabric; these and other names are sometimes found on the shelves of hardware stores.
Little-known materials that are not inferior in quality to generally recognized ones. Perhaps in 10-15 years they will gain popularity.
The cost of various heaters
- mineral wool (from 400 rubles per 1 cubic meter);
- foam and polyurethane foam (1000-3000 per cubic meter);
- natural insulation (the price reaches 10-15 thousand rubles per cubic meter).
If you have a sufficient amount of finance, it is recommended to insulate the attic from the inside with foam or polyurethane foam. Cheaper material (cotton wool) is also good, only it will take longer to tinker with it.
Based on the above characteristics of the materials used for lining the attic, the user can decide how best to insulate the attic and start implementing the plans. Each material is good in its own way, but science has not yet come up with an ideal one. Based on wishes or possibilities, among dozens of types of heaters, you can choose the most acceptable one.
The question of which insulation is better for the attic is relevant for those who decided to equip a living space under a high pitched roof of a private house. The attic differs from an ordinary room at home by increased heat loss. This is due to the fact that usually it does not have capital external walls without window openings, and on both sides and from above the room is separated from the street only by a roofing system of small thickness.
Mineral wool insulation
Criteria for choosing insulation for the attic
High-quality insulation allows you to make the attic suitable for year-round residence... When choosing a heat insulator, you need to pay attention to the performance characteristics of materials, including compare:
- noise insulation properties;
- ease of installation;
- moisture resistance;
- resistance to biological destruction;
- lifetime;
- profitability;
- environmental friendliness;
- fire safety.
But the main quality by which the material for insulation is assessed is its coefficient of thermal conductivity, on which the ability to retain heat in the room depends.
From the point of view of ease of installation and use of insulation, preference should be given to universal materials. If the same heat insulator can be used for walls, roof and floor, the insulation of all structures will last the same period.
Soundproofing properties are an especially important parameter if the roofing flooring is made of metal (seam roofing, metal roofing, corrugated board). Gusts of wind, rain and hail make such a roof "sound", and staying in the attic will be uncomfortable.
Plate heaters from a well-known manufacturer Since the roof frame is usually assembled from wood, it is advisable to use insulation that is resistant to fire and does not spread combustion. Otherwise, accidental ignition will lead to the fact that the entire attic and the roof will quickly be engulfed in fire.
To on wooden structures of the rafter system and gables, condensation did not form and the insulation did not lose its thermal insulation properties due to the penetration of moisture, it is necessary to insulate the attic room with a vapor and moisture proof material, or use a reliable hydro and vapor barrier. This affects the speed and laboriousness of the installation of the insulation layer, affects the preferences when choosing a material.
Insulation thickness
Table 1. Dependence of the thickness of the insulation on the thermal conductivity coefficient
The manufacturer indicates the thermal conductivity coefficient on the packaging of the material. This indicator depends on the production technology and the density of the insulation. The table below shows the average values:
Table 2. Coefficients of thermal conductivity of some heaters
Polyurethane foam and ecowool are modern materials that can be used as a heat insulator for attic rooms, but their installation requires the use of specialized equipment, inviting specialists. The rest of the popular heat insulators are produced in the form of plates or roll materials of various densities and thicknesses.
The insulation is cut along the width of the span between adjacent rafter legs (or the gap between the battens on the walls) and a bullet is inserted. If the estimated thickness of the thermal insulation layer exceeds the width of the rafter leg, bars of a suitable section are packed onto the rafters from the side of the room.
The most effective is a two-layer insulation - after the gaps between the rafters are filled with a heat insulator, another layer of roll material (it is possible with a foil vapor barrier outer surface) is attached over the rafters with solid butted strips. This will eliminate the formation of cold bridges.
Laying heat insulator between rafters Let's take a closer look at the main pros and cons of popular heaters that are suitable for thermal insulation of the attic roof and gables.
Fiber roll and slab insulation
- glass wool;
- mineral wool;
- stone (basalt) wool.
Their key advantage and disadvantage at the same time is the ability to pass steam. In theory, humid, warm air from the attic will escape through the breathable inner lining, heat insulator and roof system, which will help maintain a favorable indoor climate. In practice, there are the following difficulties:
- an increase in the moisture content of a fibrous insulation leads to a sharp decrease in its thermal insulation properties;
- the insulation that has gained moisture (especially glass wool) is crumpled, deformed, forming cold bridges;
- the wood of the truss system begins to rot from contact with moisture.
To avoid these problems, it is necessary to mount a vapor barrier on top of the insulation from inside the room. And between the roofing and thermal insulation must be laid waterproofing material.
Roofing cake with waterproofing over insulation Air exchange through fiber insulation will be carried out only if the waterproofing and vapor barrier layer is made of special gas-permeable membranes. The vapor barrier should allow air to pass through, but retain moisture from the room. A gas-permeable waterproofing barrier must release moisture from the insulation and prevent water from entering it.
Membrane materials are much more expensive than conventional or reinforced film, roofing material or glassine. But these investments will justify themselves due to the durability of not only insulation, but also the roof truss system.
Superdiffusion membrane If a film is used as a vapor barrier, this will reduce the cost of construction, but this will nullify the important advantage of fibrous insulation - gas permeability. You should not use perforated film, as it allows steam to pass through, which will accumulate in the insulation.
Performance characteristics of fiber insulation
Glass wool. Its positive qualities include:
- fire safety (2 degree of fire resistance);
- environmental safety (does not contain resins);
- unattractiveness for mice (do not build nests and passages);
- affordable price.
The main disadvantage is that when working with the material, stinging glass dust is formed, the installation of the heat insulator requires accuracy and the use of protective equipment. In addition, over time, glass wool tends to deform, crumple, especially when moisture penetrates.
Mineral wool... The composition of the material includes fibers of various origins (material of manufacture - clay, stone, quartz sand, glass, etc.). Mineral wool is characterized by a multi-layer heterogeneous structure with air lenses. Due to this, the material dampens sound waves well. Choosing mineral wool (primarily Isover, Ursa) is recommended for those who have decided to make metal roofing.
Such a heat insulator is fire-resistant, does not rot, and is easy to assemble. But rodents can settle in it, whose nests, passages and waste products reduce the operational properties of the insulation.
Basalt wool... Consists of fibers obtained by melting rock. Withstands heating up to 1000 degrees, does not spread combustion. Basalt wool should be chosen carefully, checking the certificates of quality and safety: some manufacturers, in an effort to reduce the cost of production, use resins that emit toxic substances.
Basalt wool Basalt wool is resistant to fungus, but can be damaged by rodents. This is a good noise isolator, easy to install. But when choosing a material for insulating a rafter system, one should take into account the rather large weight of stone wool slabs.
If you have to choose a fibrous heat insulator, pay attention to the density of the material. The heat insulator should not lose its shape even after prolonged use. For mineral, basalt wool, the density indicator should be about 40-45 kg / m3.
Polymeric materials for insulation
Choosing a polymer heat insulator for the roof and walls of the attic. It can be polystyrene, extruded polystyrene foam (these two types of insulation are produced in the form of sheets and plates of different thicknesses), as well as polyurethane foam, which is applied to structures by spraying.
The advantages of polymer insulation include low weight and low thermal conductivity. Such insulation will not overload the rafter system and will successfully cope with the task of keeping warm.
The disadvantages of polymer insulation include extremely low vapor permeability. Gas exchange is not carried out through the insulated structures, therefore, you cannot do without a well-thought-out ventilation system in the attic.
Attic insulation with polyurethane foam Thermal insulation made of extruded polystyrene foam (foam) and polyurethane foam will not allow heat and steam to pass to the roof truss frame, therefore, there is no need to install a vapor barrier from the side of the room. Despite the fact that the dew point during the internal insulation of the gables will shift towards the heat insulator, moisture that is dangerous for wood will not condense.
All joints and abutments of foam insulation must be filled with polyurethane foam and (after removing excess foam) glued with reinforced tape so that the insulation layer is airtight.
Manufacturers produce penoplex of various densities. For pitched roofs and attic walls, where heat loss is high, it is advisable to use slabs with a density of 30-35 kg / m3.
If you decide to choose an inexpensive foam plastic, it is better to install insulation according to the same principle as fiber board materials. Unlike extruded polystyrene foam with a solid closed-cell structure, the foam consists of many individual granules pressed into a board. Technological pores remain between the structural elements, which are capable of passing steam to the wooden structures.
The suitable density of the foam is 35 kg / m3, at a break, the material should not crumble into individual balls. Since the foam smolders when ignited with the release of toxic substances and is easily gnawed by mice, this is not the best material for internal insulation.
Polymeric insulation for the attic should not be considered as a soundproofing material for the roof - it will not save rain drops from knocking. But if you insulate the floor with it, it will reduce the vibration load from steps, creating acoustic comfort in the rooms under the attic.
The chosen insulation option will last long yearsif you buy good stuff and take into account all the subtleties of its installation.
Equipping the roof with insulation is one of the most important stages in the construction of a roof, which is designed for long-term operation.
External insulation
This process is not difficult and is carried out according to the following algorithm:
- Primarily the rafters from the bottom hemmed with plywood or edged board.
- Thereafter carry out the laying of a layer of thermal insulation... The surface of the layer and the joints are glued with foil tape. It is very important to lay the vapor barrier on the right side, because this material is able to function in one direction.
- Next, the insulation material is laid... In this case, free space should be avoided, it is necessary that the insulation lay tightly.
- The next step is hydro-barrier layout on top of the rafter structure... Bonding is also carried out with a specialized tape.
- Penultimate make ventilation gaps... This process is carried out using a rail that is placed over the hydro-barrier. The height of the rail is selected depending on the parameters of the roofing. If the roof is of a corrugated type, then the standard of the slat is 20-30 mm, if the roof is flat, then 50 mm.
- The last carry out the installation of the lathing and lay the roof.
Considering that the material does not have protection against precipitation, the work should be carried out only in clear weather.
External insulation
Insulation of the attic roof from the inside
At first glance, one can decide that this method of insulation is more reliable and practical due to the fact that precipitation does not fall on the material, because protected by a roof covering.
However, this method has disadvantages.:
- It is very inconvenient to install most of the material from the bottom side up, and it is impossible to fix roll materials in some places;
- The rafter system contains elements to strengthen the structure, the mating points of which are not protected by heat-insulating material.
Stages of installing a heat-insulating layer internally:
- Installation starts from the bottom of the roof and a film with waterproofing properties is laid with an overlap, held together with adhesive tape. In places located near walls, the coating should have a larger margin, which is adjusted after the completion of the entire process.
- Equip the structure with counter rails, which are attached to the rafter system with nails. This is necessary to ensure a ventilation gap and a snug fit of the layers to each other.
- Thereafter carry out the laying of insulation.
- The last step is vapor barrier equipment, which is fixed with overlapping construction brackets.
CAUTION!
It is not recommended to seal cracks and gaps with construction foam. In order to avoid unnecessary distance between the sheets, it is best to stack them with a margin of 5 m.
Internal insulation
Conclusion
Which installation method to choose for arranging a thermal insulation structure for a mansard roof largely depends on the individual parameters of the structure. You should initially study in full all the nuances and conditions.
Useful video
In this you will learn how to properly insulate the attic roof:
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