The attic is a room equipped under the roof, used for permanent residence or just to have a good time. Attics are widely popular in many countries, but for their comfortable arrangement, it is very important to equip them with a thermal insulation system that prevents heat loss through the roof slopes.

Basic requirements for insulation for an attic roof

To insulate the roof of an attic, various thermal insulation materials can be used, when choosing between them, pay attention to the following characteristics:

• low thermal conductivity;
• high frost resistance and resistance to defrosting;
• resistance to significant temperature fluctuations;
• low hygroscopicity, minimal moisture absorption;
• non-flammability;
• long period of operation.

On the other hand, when choosing insulation, factors such as slope and shape are also important. roof slopes, climatic and weather conditions of the area, the purpose of the attic being equipped, etc. Not only the preference for one material or another depends on such nuances, but also what density of insulation is needed for the attic, the thickness of the insulation mansard roof and some other parameters.

Basic materials for arranging thermal insulation of the attic

The choice of insulation materials on a modern construction market quite large, however, the following are most often used for thermal insulation of attic roofs:

• mineral wool;
• Styrofoam;
• polyurethane foam.

Each of these materials has its own characteristics, advantages and disadvantages, which are worth dwelling on in more detail. Let's figure out which insulation is best for an attic roof in order to make the right choice.

Mineral wool - density and thickness of mineral wool

Mineral wool is perhaps the most common insulation for attic roofs due to its low cost and good thermal insulation qualities. In addition, the advantages of this material are also fire resistance, good breathability and low hygroscopicity. On the other hand, the thermal insulation characteristics of mineral wool are significantly reduced when wet, which makes it mandatory to equip it with waterproofing and vapor barrier membranes.

Mineral wool has several varieties:

• glass wool;
• slag;
• basalt or stone wool.

Glass wool is made from the finest glass fibers 5-15 microns thick and 15-50 millimeters long. It has an elastic and durable structure, and requires great care when working: to avoid irritation, when laying it, wear a protective suit, gloves, goggles and a respirator. Resistant to temperatures from minus 60 to plus 450-500 °C.

Slag wool, made from blast furnace slag, contains fibers 4-12 microns thick and approximately 16 millimeters long. This material can withstand heating up to 300 °C, but is ineffective when arranging thermal insulation of the attic due to its high hygroscopicity. In addition, slags with residual acidity can have an aggressive effect on metal surfaces, which is also a significant disadvantage. The disadvantages of slag wool are also its fragility and “prickliness”, which creates inconvenience when working with it with bare hands.

Basalt (stone) wool is made from gabbro-basalt or diabase with composite and binding additives. Its fibers are approximately the same size as those of slag wool. In terms of technological characteristics, this material is superior to all other types of mineral wool, and therefore is especially often used for thermal insulation of attic roofs. Stable when heated up to 600 °C (some types - up to 1000 °C). When using this type, the elasticity and density of mineral wool for attic insulation are sufficient so that the material does not wrinkle or settle when installed on slopes.

As for the required thickness of mineral wool for insulating an attic, it largely depends on climatic conditions, averaging 15-30 centimeters. It is clear that in regions with colder and more humid climates, the thickness of the insulation for the attic roof should be relatively greater.

Styrofoam

Foam plastic is a modern thermal insulation material based on polystyrene foam. Its structure is hardened polystyrene foam, inside of which there are many air bubbles.

The advantages of polystyrene foam are light weight, excellent thermal insulation characteristics, low hygroscopicity and good sound insulation properties, which, combined with an affordable cost, make it one of the most preferred materials for insulation. At the same time, the disadvantages of polystyrene foam, which should be taken into account when arranging an attic, are flammability, instability to high temperatures and ultraviolet rays, as well as low strength.

To improve performance characteristics, some manufacturers treat foam products with fire retardants, which increases their service life by several years, which makes attic insulation with foam economically profitable.

It should also be said about what layer of insulation is needed for the attic if this material is used. The required thickness for most climatic zones is 15-20 centimeters, but in frosty regions it makes sense to increase it to 25-30 centimeters.

When installing thermal insulation mansard roof made of foam, it is important to ensure good ventilation of the under-roof space, since this material is not “breathable”. Otherwise, this may lead to condensation, mold and putrefactive processes.

Polyurethane foam

Polyurethane foam is a polymer insulation, which is a type of foamed plastic with a cellular structure. The cells are filled with a gaseous substance, which provides effective thermal insulation properties of this material.

The advantages of polyurethane foam are versatility, low flammability, lack of hygroscopicity, resistance to aggressive chemical influences, low thermal conductivity and durability. Although in terms of thermal insulation characteristics it is slightly inferior to foam plastic and mineral wool, it is several times longer than them in terms of service life.

Polyurethane foam insulation is available both in the form of slabs and in the form of sprayed liquid mixtures. The last option is the most versatile and effective: it can be applied to any material, while closing all the cracks and gaps.

It should be noted that if in the case of tiled materials the calculation of insulation for the attic may present certain difficulties, then when spraying liquid polyurethane foam no special calculations are required. The whole process can easily be carried out with your own hands in a short time - all you need is the presence of a thermal insulation composition and equipment for spraying it.

Another important advantage is that liquid polyurethane foam is sprayed without seams or joints, completely repeating the complex shapes of inclined and other surfaces. This results in significantly more effective thermal insulation. Therefore, if we talk about what thickness of insulation should be in the attic, then a layer of 10-15 centimeters is usually sufficient.

Tiled forms of polyurethane foam are also used for insulating attic roofs, but are somewhat less convenient and practical.

Other types of insulation for attic roofs

Along with those listed, other materials are sometimes used for thermal insulation of attic roofs, although their prevalence is not so great.

For example, in some regions it has not lost its importance old method– insulation with felt. Besides, in last years New types of effective thermal insulation materials, which appeared on the construction market relatively recently, are also gaining popularity. This includes, for example, ecowool and modern fiberglass insulation. It is also worth noting that, along with the considered types of insulation, their foil varieties are often used, the cost of which is somewhat more expensive.

It is clear that the calculation of attic insulation may have certain features depending on the type of insulation used and a number of other factors.

So, for example, the answer to the question - how thick should the attic insulation be - can be broadly formulated as follows:

• the greater the thermal conductivity of the material, the greater the thickness of the thermal insulation layer should be;
• for areas with a milder climate, thinner insulation is required, for more severe climatic zones - vice versa;
• a large number of joint areas and seams contributes to heat loss, necessitating the need for greater thickness of insulation.

The correct choice of material for thermal insulation and well-made calculations serve as the basis for ensuring thermal comfort in the attic room, literally contributing to a warm atmosphere in it at any time of the year.

The popularity of attics is growing rapidly. Developers consider this type of housing to be less expensive compared to the cost of equipping floor premises. In addition, many homeowners are attracted by the opportunity to implement specific architectural and design solutions, substantively developed by European specialists. Why has the transfer of under-roof zones to housing become actualized in our country 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 make it possible to choose insulation for the attic, providing a comfortable microclimate in a “house without walls” located somewhere in the Moscow region.

It is important to choose the right insulation for the under-roof space

The installation of attic roofs is functionally and technologically different from the work carried out on the main floors and in unheated attic spaces. Insulation of the attic is associated with increased complexity of installation processes, the need for thermophysical calculations, as well as the importance of proper development of ventilation and vapor protection.

In non-residential attic spaces, thermal insulation is laid in the niches between the ceiling beams. In this case, the roof structure plays the role of a barrier that protects the building from wind load, temperature expansion and precipitation. Insulation for the attic roof, on the contrary, is included in roofing sandwich, designed to simultaneously perform all the functions inherent in the walls, ceiling and roof.

More moisture enters the attic than the floor spaces. Water penetrates from below in the form of rising vapor. Vapor barrier of the floor ceiling reduces the flow of moisture, but does not eliminate it.

The second factor in air humidification is associated with the inevitable condensation on the bottom surface of the tiles or other roofing material. Moreover, the amount of this condensate on insulated roofs is greater than on cold roofs due to the increased temperature gradient. In addition, a ventilated cold attic forms a buffer air cushion, effectively drying the roof from below. The absence of such a buffer in attics reduces the natural ventilation of wooden rafters and the insulation itself.

Placing thermal insulation directly under the roof slopes increases the rate of heat transfer, so insulation for the attic should be more energy efficient than insulating the floor between the dwelling and the cold attic.

Criteria for selecting insulating material

What is the best way to insulate an attic? Studying the properties of thermal insulators cannot give a substantiated answer to this question. It is necessary to correlate the characteristics of materials with their operating conditions. The specificity of attics is expressed in three main rules for their insulation:

1. Timeframe for completing thermal insulation work. Typically, freshly sawn wood is used for rafters. In this case, it is necessary to wait at least six months before insulation is carried out with materials with high vapor permeability.
   

   Even when using dried wood, a pause of at least 2 weeks is necessary after installing the roofing.

2. Choice of insulation thickness. The intensity of heat flow through the roof is much greater than the energy lost through the walls or foundation. The usual thickness of mineral wool of 100 - 150 mm does not solve the problem of attic insulation even in the southern regions of Russia. It is necessary to use special calculator programs where you substitute climatic conditions, dimensions building structures and materials of all layers of the sandwich. In conditions of a temperate continental climate, the required design thickness of the insulator for a mansard roof is almost never less than 300 mm.
3. Design of rafter 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 convert a cold attic into housing, then additional sheathing is usually used at the bottom of the rafters, increasing the installation height to accommodate the insulating layer.

To determine which insulation is best for your attic roof, make comparative assessment materials taking into account the above three rules in the following order:

1. Eliminate options that do not meet your requirements fire safety.
2. Eliminate options with high vapor permeability of insulation if you do not have time to dry the rafter wood.
3. Calculate the required insulation layer thickness for several options.
4. Create budget options. In this case, it is necessary to take into account the exclusion of a vapor barrier membrane from the sandwich composition in the case of using insulating materials with hygroscopicity close to zero.

Types of insulating materials used for insulating attic 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 down will block the ventilation gap. Therefore, sawdust, fluff pulp, expanded clay and similar insulation materials should be abandoned. On the other hand, it is permissible to carry out insulation with slabs obtained from a mixture of the listed materials with clay or cement. However, the weight of such slabs should be taken into account when calculating trusses.

Fireproof insulation

The only relatively inexpensive fireproof heat insulator is mineral (basalt) wool. It is for this reason that she for a long time remains the most popular option for attic sandwich applications. How to choose a good mineral wool insulation for the attic? Is the usual rolled isover that we use for walls suitable? Such material will work well, but... not for long. The reason for this is high capillary activity. Therefore, it is necessary to choose materials with special impregnations that reduce hygroscopicity: mineral wool ROCKMIN PLUS, Izover Pitched Roof and other brands whose names have a direct indication of the area of ​​application that suits us.

Mixtures of insulating backfill with clay are also fireproof. The main problem with clay-mixed insulation is the very large thickness of the insulating layer and its excessive weight.

Among the most modern developments, PIR boards lined with heat-reflecting foil should be highlighted. They do not support combustion and have a record low thermal conductivity coefficient (0.024 W/m*K).

Insulation materials with the highest energy efficiency

Manufacturers of building thermal insulation have developed brands of extruded polystyrene foam (EPS) slabs specifically designed for the installation of attics and cold attic roofs. These are Penoplex Pitched Roof, TechnoNIKOL Carbon Solid and other materials with a thermal conductivity coefficient of no higher than 0.030 - 0.034 W/m*K. Brands are distinguished by the ability to order panels of increased length (up to 4.5 m), which significantly speeds up installation work.

EPPS - flammable material, But building codes allow its use in attic 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, foil can significantly increase the fire resistance of the sandwich.

On average, polystyrene foam boards make it possible to reduce the thickness of the attic insulation layer by 20% compared to mineral wool. The champions in heat conservation are sprayed polyurethane foam (PPU) and the already mentioned PIR boards. Due to the high toxicity of gases released during thermal destruction of polyurethane foam, this material is not recommended for use in residential attics. PIR boards do not have this drawback and are able to replace mineral wool with a 1.5-fold reduction in layer thickness.

Insulation materials with high specific noise absorption

Insulation with Zhivoizol - linen heat insulator

The noise insulation properties of attic roof insulation can be very important when using metal tiles, which enhance the noise of natural precipitation. Currently, slab materials have been developed that are characterized by a high noise reduction coefficient with a slight loss in energy efficiency to mineral wool. Among such developments, it should be noted pressed flax insulation, known under the market brands “thermolen” and “ZhivaIzol”. Plates made of this material absorb noise in all frequency spectra 20% - 30% more effectively than mineral wool and EPS.

Conclusion

The choice of insulation for an attic roof should be carried out in parallel with the development of roof trusses and the design of the entire sandwich, including roof cladding, membranes and sheathing. When converting cold attics into housing, 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, not only leads to cold in the attic room. Even if you compensate low temperature intense heating, you may encounter:

• increased roof icing;
• reducing the service life of the roofing covering;
• failure of the drainage system.

Thus, competent design of a roofing sandwich for attics is important not only to ensure comfort for residents, but also from the point of view of increasing the service life of the building.

Video on the topic: how to properly insulate an attic

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Which insulation is best for an attic roof - choose from 5 options

Highly insulated attic floor- This excellent solution shortage of living space. It is possible to insulate a room under a roof with your own hands, but with such an abundance of thermal insulation materials on the modern market, it is important not to make a mistake with your choice. To make it easier for you to decide on the type and thickness of the material, then we will analyze in detail the characteristics of 5 insulation materials, plus I will make a short review of prices.

Where to look when choosing

The attic belongs to quite specific residential premises. The main difference is the absence of main walls. More precisely, some models have so-called attic walls (a continuation of the main wall), but their height often does not exceed 1.2 m, so they do not play a big role in thermal insulation.

Since there is no capital base, the entire load in terms of insulation falls on the thermal insulation materials. There are general ideas about what insulation for an attic floor should be.

• One of the most basic parameters when choosing a material is the thermal conductivity coefficient. Remember - the lower the thermal conductivity coefficient, the better the thermal insulation is considered;

• The material must be resistant to sudden temperature changes; during such changes it should not crack or shrink. In the attic part, the thermal insulation from the street is separated only by the roofing material and a windproof membrane, so it is important how many freezing cycles the insulation can withstand;
• The level of hygroscopicity is no less important for any insulation, because the ability to absorb moisture at times and moreover a short time can increase thermal conductivity. But even if the material is hygroscopic, it is desirable that when it dries it does not lose its properties;
• According to statistics, the attic space is considered the most fire hazardous; a dry, unprotected roof will burn out in 5–7 minutes during a fire. Ideally, the insulation should not burn at all or at least not support combustion;
• The complexity of the arrangement technology plays an important role. Even if you don't intend to do it yourself, than more difficult installation, the more the craftsmen will have to pay for it;
• Thermal insulation occupies the bulk of the roofing pie and at such a concentration it is important that the material is completely safe for humans. Living in a poisonous “bag” is not the best The best way save.

In practical terms, when it comes to purchasing, it is important to choose the thickness of the insulation. The thickness of the material depends on several factors:

• First of all, from the material itself, but we will talk about this later;
• The second criterion is density; here it is important to find the golden mean, and for each climate zone this mean is different;
• Again, hygroscopicity, water-permeable materials must be taken with reserve;
• But most main characteristic Thermal conductivity influences the thickness; it should be as low as possible.

What kind of insulation does the market offer?

If you are looking for a universal insulation that is the best in all respects, then I will tell you honestly - this does not exist in principle. Depending on the roof design and climate zone, there are more and less common materials.

Option No. 1: foam

Polystyrene foam is considered a proven, reliable and, importantly, inexpensive insulation material. It contains only about 3% polystyrene, and the remaining 97% is air. Polystyrene is indifferent to moisture, which means it does not absorb moisture at all.

With any insulation of a house, there is such a thing as the dew point. In a nutshell, this is the place where plus and minus meet; it is in this zone that condensation settles. So, with foam plastic, the dew point is inside the slab and, in principle, there cannot be condensation there.

The slabs are light, but at the same time quite rigid, which greatly facilitates calculations and installation. Like most insulation materials, polystyrene foam has good soundproofing properties. Although not everything is so smooth, this material also has a number of serious disadvantages.

The fact that the material does not absorb moisture is good, but at the same time, it does not allow it to pass through. The attic is the upper room in the building, therefore there is the highest concentration of household fumes.

If you decide to insulate the attic with polystyrene foam, you will have to install forced ventilation, otherwise the vapors will condense under the ceiling, which will lead to mold, after which the wood of the rafters will begin to deteriorate, and with a high concentration, water will simply drip from the ceiling.

Polystyrene foam supports combustion, although it does not burn strongly; in the event of a fire it will release harmful, suffocating gases. Foam plastic is safe for humans, but rodents love to live in these slabs and it is very difficult to get them out.

For middle zone In Russia, slabs with a thickness of 50–70 mm are enough, in Siberia you need to lay 100 mm, and the further north you go, the thicker it is. As for the brand, slabs from PSB-S-25 and denser are used here.

The prices in the article are current in the fall of 2017.

Option No. 2: extruded materials

Extruded polystyrene foam is, figuratively speaking, an advanced brother of polystyrene foam. The same polystyrene is used here, only the sheets are made by extrusion; as a result, instead of compressed balls, a monolithic slab of foamed polystyrene is obtained.

Many people consider such well-known brands as “Penoplex” and “Technoplex” to be independent types of insulation. So - all this is extruded polystyrene foam, produced by different manufacturers.

Such slabs are distinguished by lower thermal conductivity, compared to foam plastic; it is lower by about a third. Where polystyrene foam is installed with a thickness of 70 mm, EPS can be installed with a thickness of 50 mm, plus the durability of the boards is at least 30–40 years, versus 20–25 years for polystyrene foam.

As for the minuses, almost everything that foam plastic has was transferred to extruded polystyrene foam (except that rodents do not live in it), plus it is almost 2 times more expensive.

Option No. 3: different types of mineral wool

Not everyone knows, but the term mineral wool combines several different materials, which differ in their characteristics.

Absolutely all types of wool absorb moisture, but high-density boards have the ability to retain their characteristics after drying.

Illustrations	Recommendations
	Stone wool. This direction is made from volcanic minerals. Insulating the attic with stone wool is considered the most the best solution. It is absolutely harmless, quite durable and does not burn. Most often, basalt wool is used for these purposes; it’s just that this mineral is the most common, and therefore affordable. The thickness of the slabs for attic insulation starts from 100 mm.
	Glass wool. Glass wool is much cheaper than its stone sister. The material is environmentally friendly, but not all brands of glass wool are good; budget models shrink quickly and require caution during installation (small glass needles dig into the skin).
	Slag. In terms of its thermal insulation characteristics, slag wool is not much inferior to stone types of wool, but it is not worth using for insulation of interior spaces. This material is made from blast furnace slag and during operation, the slag releases vapors of phenol and other dangerous poisons.

For the attic and, in general, any roofing project, mineral wool should be taken in high-density slabs. Under no circumstances use soft mats; they are not suitable for roofing and will quickly become unusable.

Option No. 4: ecowool

A new unique material called ecowool is nothing more than a product of recycling waste paper. 80% of it consists of natural cellulose, the rest goes to additives and binders.

Ecowool is ideal for the attic, but to apply it to the walls and ceiling you need to invite specialists with special compressor equipment. This material is sprayed onto the surface. But thanks to the additives, it does not burn and does not lose its properties after getting wet.

Option No. 5: polyurethane foam

An excellent material for insulating any surface. In its structure, polyurethane foam is partly similar to polyurethane foam, although the composition is different. There is no need to worry about the solidity of the layer here, because the material is sprayed onto the walls and, after hardening, forms a sealed shell.

Polyurethane foam is durable, lightweight and does not support combustion, everything about it is good, except that the price of the material is quite high and specialists with equipment are needed to install it.

Conclusion

The attic is a specific room and when choosing insulation for it, you need to take into account all the pros and cons that were mentioned above. The video in this article contains other interesting nuances of choice. If you have any questions, write in the comments, I will try to help.

October 16, 2017

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September 7, 2016
Specialization: Capital construction works(laying a foundation, erecting walls, constructing a roof, etc.). Internal construction work (laying internal communications, rough and fine finishing). Hobbies: mobile communications, high technology, computer equipment, programming.

I recently started converting the attic in my client's house from junk storage into living space. And I wondered what is the best attic insulation to use in this case? After all, each of the heat insulators on the market has its own characteristics, which are better manifested in certain conditions.

Therefore, today I will tell you how to choose a thermal insulation material for the job. I think this information will be of considerable interest to everyone who is going to build a house and equip it with their own hands.

Features of choosing insulation for the attic

When arranging an attic, it is necessary to carry out insulation. Moreover, regardless of whether this room will be used in winter or not. Properly selected and installed thermal insulation material not only prevents unproductive heat loss, but also protects the room from heat, creating a microclimate inside that is comfortable for people to stay in.

In addition, the insulating pie makes it possible to protect and increase the service life of building structures - roofing material, rafters, sheathing, and so on.

After insulation, all parts will be protected from moisture and temperature fluctuations, which destroy the internal structure of the material. However, to achieve the benefits described above, you must use the right insulation material.

When considering the question of which insulation to choose for the attic, first of all, it is necessary to take into account the climatic conditions of the area where the dwelling is built. The characteristics of the material used depend on this – primarily its density and thickness.

In addition, it is important to pay attention to the design features of the walls, roof, gables, roof angles, shape of the room, etc. In some cases, the attic configuration is so complex that sheet materials It will be very difficult to perform thermal insulation and you will have to choose more technologically advanced options.

When choosing the best insulation for an attic room, I would advise you to pay attention to several more important criteria, which are shown in the table below.

Characteristic	Description
Temperature resistance	Thermal insulation must maintain its technical characteristics and operational properties both in severe frost in winter and in hot summer. Consecutive cycles of defrosting and thawing should not reduce the thermal conductivity of the insulation and destroy its internal structure.
Hydrophobicity	The material must be waterproof or not accumulate water inside the insulating pie. Moisture not only reduces the performance properties of the heat insulator, but also destroys it, reducing its service life.
Fire safety	Preference should be given to those materials that do not ignite during a fire and do not support the spread of flame. As a last resort, you need to buy insulation materials that contain fire retardants, which contribute to the self-extinguishing of the insulating layer. Please note that some types of insulation, when ignited, emit toxic smoke, making it difficult for people to evacuate.
Saving dimensions	The insulating material must maintain its geometric dimensions throughout its entire service life. Otherwise, after installation, the thermal insulation will shrink, forming islands of cold that nullify all efforts to insulate the under-roof space.
Strength	If you are thinking about which insulation to choose for arranging a floor, then give preference to durable heat insulators that can withstand constant dynamic and static loads. Otherwise, you need to design a system with logs to protect the insulating pie.
Ease	It is better to purchase insulation that has minimal weight so that after installation it does not put a significant load on the structural elements roofs, attic floor And load-bearing walls building.

Considering the above, I cannot say 100% how better insulation insulate the attic. Therefore, I will describe the technical characteristics of the materials that are most acceptable, from my point of view, so that you can choose the option that suits you.

Specifications

There are many insulating materials, but for arranging a room under a roof, in my opinion, those indicated in the diagram below are most suitable:

Option 1 - Mineral wool

When talking about this type of insulation, I will have in mind one type of thermal insulation - basalt wool, since it has higher technical characteristics than glass wool and slag wool.

This heat insulator is made from a volcanic mineral - basalt. Raw materials are melted in furnaces at high temperature, after which thin fibers are formed from it, which are then glued together with resins.

Thanks to this, the material acquires increased strength and does not pose a danger to human health. However, these are not all the advantages that I personally value and thanks to which I most often use basalt wool in my work.

Other advantages are:

1. Low thermal conductivity. Fibers in basalt wool are spaced from each other at a certain distance, and the spaces between them are filled with air, which, as is known, conducts poorly thermal energy. The thermal conductivity coefficient of the material is 0.032-0.048 W/(m*K), so the thickness of mineral wool for effective insulation is no more than 10 cm.
   To convince you, I will resort to some comparison. A standard 10 cm layer of insulation with a density of 100 kg per cubic meter retains heat with the same efficiency as a 110 cm wall made of red brick or a 160 cm wall made of silicate blocks.

1. High vapor permeability. Insulating the attic with mineral wool from the inside in no way prevents air from penetrating through the roof structure. This is due to the fact that the material has an open cell structure filled with air.
   This is very important for living quarters, where human activity generates a large amount of water vapor. Excess moisture will escape through the insulation layer, creating a comfortable microclimate for living in the attic. The vapor permeability of mineral wool is 0.3 mg/(m*h*Pa).
2. Minimal moisture absorption. The material has hydrophobic properties, so it does not lose its technical characteristics when water flows through the roof space. The basalt wool fibers themselves are absolutely waterproof, and the accumulation of moisture inside the insulating cake is prevented by hydrophobic additives in the adhesive resins.
   Research shows that in direct contact with liquid, high-quality basalt wool absorbs no more than 2% of the liquid from its own volume. However, I still recommend using waterproof membranes when constructing a roofing pie.

1. Fire safety. Cotton wool is made from a mineral of volcanic origin, so it does not ignite in a fire. According to the classification of building materials, the described insulation has the NG index (non-flammable). Basalt wool melts and loses its properties when the temperature exceeds 1100 degrees Celsius.
   Based on the above, basalt wool is like no other material suitable for arranging attics. The insulation layer in this case will not only perform heat-insulating functions, but also serve as a fire barrier.
2. Mechanical strength. As I already said, the fibers of basalt wool in the insulation are located chaotically and many of them are oriented perpendicular to the insulating mats, which determines the ability of the material to withstand high compressive loads.
   When the insulation mats are deformed by 10%, it has a compressive strength ranging from 5 to 80 kPa ( exact value depends on the density of the material).
   Translated into simple language, this means that dense mineral mats can be used to insulate the attic floor under. At the same time, the integrity of the insulating layer is fully guaranteed throughout the entire service life.

1. Soundproofing properties. The open structure of the material ensures that the insulating layer absorbs sound waves very effectively. For an attic, this criterion is one of the most important, since the noise made by rain falling on a hard roof often causes discomfort for people living in the attic.
   Moreover, mineral wool has the ability to reverberate sound waves, therefore protecting not only the attic itself, but also the adjacent rooms from noise.
2. Environmentally friendly. Mineral fibers themselves are absolutely safe for humans, however, formaldehyde resins used for gluing can become a source of emissions harmful to health chemical compounds. To avoid this, the material is subjected to secondary heat treatment, during which the phenol is neutralized. The final emission is much less than the safe level established by regulations, and is no more than 0.05 mg per square meter. meter of material per hour.
   Another advantage of basalt wool is that the mats themselves do not prick, do not cause irritation to the skin and allergic reactions in people who are prone to this.

1. Biological and chemical resistance. Mineral wool is absolutely neutral to aggressive biological environments. Mold and fungus do not develop in the thickness and on the surface of the insulation, the material is not prone to rotting, and is not damaged by rodents and insects.

In addition, basalt fiber withstands exposure well chemical substances, therefore it can come into contact with building mortars and is not damaged by acids dissolved in rainwater, which can leak under the roofing.

1. High price. There are more economical solutions that are not inferior in efficiency to the material described above.
2. Presence of seams. Mineral mats are joined to each other and to the rafters. As a result of a loose fit, cold bridges may form in these places.

Option 2 - Expanded polystyrene

I often used ordinary polystyrene foam, which is correctly called polystyrene foam, to insulate attics, although with some reservations. And the point here is not only in cost (and the price of polystyrene foam is really the lowest among alternative materials), but also in large quantities other benefits.

I'll tell you about the most important of them:

1. Low thermal conductivity. As with mineral wool, polystyrene foam does not conduct heat well due to the air contained inside. However, here the gas is enclosed in small closed cells glued together. Moreover, the polymer occupies only 2% of the total volume of insulation, and the rest is filled with air. Considering that the latter is devoid of convection, this has a positive effect on the heat-retaining properties.
   The thermal conductivity coefficient of expanded polystyrene is lower than that of mineral wool and ranges from 0.028-0.034 W/(m*K). However, the exact answer to the question of what layer is needed to insulate attic walls depends on the density of the selected material. In most cases, 5-10 cm is enough.
2. Classic construction foam does not allow air to pass through due to its hermetically sealed structure. To equip the attic, you can use extruded polystyrene foam, which transmits from 0.015 to 0.019 mg/(m*h*Pa).
   And if we talk about water absorption, then the opposite is true. Simple polystyrene foam can absorb up to 4% of liquid from its own volume, and extruded polystyrene foam - no more than 0.5%.

1. Good strength. Both regular and extruded polystyrene foam tolerate mechanical loads well. But if you are going to insulate the attic floor using a reinforced concrete slab, then buy EPS. If ordinary foam plastic can withstand a bending load of 0.02 to 0.2 kg per square centimeter, then for extruded foam this figure is 0.4-1 kg.
2. Chemical cost. Polystyrene foam is good because it does not react in any way to household detergents, alkaline solutions and mineral fertilizers. In addition, it can be coated with bitumen resins, cement mortars and similar materials.
   However, polystyrene foam disintegrates upon contact with acetone, turpentine, varnishes, drying oil and petroleum products. In addition, it is not recommended to expose polystyrene foam to direct ultraviolet rays, so the insulating layer in the attic must always be protected with external decorative materials.

1. Sound absorption. Expanded polystyrene does not absorb sound well. However, if you lay it in a layer of 10 cm, it copes with the absorption of noise during rain. But if necessary, polystyrene foam must be combined with effective sound insulators in order to completely damp out noise from outside.
2. Antiseptic. Manufacturers of expanded polystyrene carried out Scientific research, which proved that the development of any living organisms on the surface of this insulation is impossible. Therefore, using polystyrene foam to insulate the attic, you can be 100% sure that mold and mildew will not appear in the insulating layer.
   Rodents are a different matter. Although they do not feed on polystyrene foam granules, they still like to build passages and nests in the thermal insulation layer. Damaged foam loses its heat-retaining properties. If your house is located in a remote summer cottage, abounding in mice, it is better to give preference to basalt wool, which is too tough for them.

1. Flammability. Polystyrene foam, as you probably know, belongs to the category of the most flammable insulating materials (G3 and G4). In addition, the material is highly flammable and contributes to an increase in the source of fire, while emitting toxic smoke that is harmful to human health.
   To insulate the attic, it is necessary to use only such polystyrene foam, in the production of which substances - fire retardants - are added to the composition of the raw materials. They will not protect the foam from fire, but will limit the spread of fire and make it possible to evacuate people from the attic floor.
2. Lifetime. The service life of the insulation provided by the manufacturer is 30 years. However, such results can be achieved if the technology for installing and operating polystyrene foam is strictly followed.
   The most important thing is to choose the right thickness of the insulating layer during the insulation process. For central Russia, it is enough to install a sheet of polystyrene foam 10 cm thick or two sheets of 5 cm each. If you use thinner foam, the effectiveness of thermal insulation will be low; if it is too thick, the insulating cake will collapse as a result of exposure to some external factors.

1. Environmentally friendly. In the production of polystyrene foam, no gases are used that are harmful to the environment. However, during operation the insulation begins to oxidize. Moreover, this process takes place faster in classic polystyrene foam compared to EPS.
   The oxidation process begins when the surface is heated above 30 degrees Celsius. This releases toluene, formaldehyde, methyl alcohol, acetophenone and many others. hazardous substances. Therefore, when using polystyrene foam to insulate attics, it is necessary to equip ventilation gaps, promoting cooling of the material.

As you can see, expanded polystyrene - regular and extruded - can be used to insulate the attic, albeit with some reservations. However, the latter are entirely justified by the savings in money.

If for you economic factor it doesn’t matter, I recommend paying attention to sprayed insulation, which I will discuss below.

Option 3 - Polyurethane foam

This insulation belongs to the category of sprayed heat insulators. It is made from polymer raw materials, which foam as a result of a special chemical reaction and, after hardening, form a porous insulating layer of closed cells filled with carbon dioxide.

To insulate attics, you can use two types of insulation:

1. Two-component. Formed by mixing a polyol (component A) and a polyisocyanate (component B) into special device followed by spraying the mixture onto insulated structures using a gun connected to a compressor. This composition is used to insulate large surfaces.
2. One-component. Supplied in metal cans with a capacity of 1 liter, completely ready for use. Spraying occurs using a gun on which the container is placed. Such insulation (for example, Polinor) is used to treat small, hard-to-reach areas of the attic and is often combined with other insulation materials.

Two-component polyurethane foam comes in different densities and structures. For interior work For insulation of the roof space, I recommend using Ecotermix 600 with an open cell structure and a density after hardening of 9 to 12 kg per cubic meter.

Due to its porosity, the material has a low thermal conductivity coefficient and effectively protects the room from unproductive heat loss.

Now I’ll tell you about the specific technical characteristics of sprayed polyurethane.

1. Low thermal conductivity. Carbon dioxide is as bad a conductor of thermal energy as atmospheric air. Therefore, in terms of thermal conductivity, this insulation is not inferior to the alternatives described above.
   The exact value of λ is 0.023 W/(m*K) for a material with a density of 32 kg per cubic meter. I usually spray polyurethane foam so that its surface, after hardening, is at the same level as the lower edge of the rafters. That is, the insulation layer is 100-150 mm.

1. Moisture absorption and air infiltration. The material does not absorb water, so there is no need to take additional measures to protect it from moisture. In addition, it well protects insulated structures from exposure. This property is used to insulate metal parts and pipes, which are simultaneously protected from corrosion.
   As for vapor permeability, it all depends on the structure of the cells. The material for outdoor use has closed pores and is therefore not classified as “breathable”.
   And the attic can be insulated with an open-cell insulator, which allows you to remove excess moisture from the wooden rafters and regulate the level of water vapor in the air.
2. Good strength. After hardening, polyurethane foam has sufficient compressive strength. Therefore, the insulation layer can not only be covered with sheet materials such as plywood or drywall, but also plastered with a thin layer of cement mortar.
   What also attracts me personally is the ability of polyurethane foam to further strengthen the very truss structure roofs, strengthening the enclosing walls of the attic and not placing a large load on other structural elements.

1. Chemical resistance. The insulation tolerates contact well with alkali-containing building materials, as well as acids dissolved in rainwater. What you should be wary of is contact with petroleum distillates, which melt the foam.
   Another important point– UV protection. Polyurethane foam disintegrates when exposed to sunlight, so it must be carefully protected from them.
2. Sound absorption. According to this indicator, the foam is more reminiscent of polystyrene foam than mineral wool. It protects the room well from impact noise created by raindrops falling on metal tiles or profiled sheets. But polyurethane foam cannot be used as an independent sound insulator.
   Sprayed insulation with an open cell structure absorbs airborne noise better, so use it.

1. Antiseptic. The presence of polymers in the spray foam and zero water absorption means that microorganisms cannot develop on the surface and in the thickness of the insulating layer, so additional antiseptic treatment of the insulating layer is not required.
   The same applies to insects and rodents. Mice don't like foam, so you don't have to worry about such an unpleasant neighborhood.
2. Flammability. The material, due to the presence of fire retardants in component A, belongs to categories G2 and G3. Although the insulation is flammable, it does not contribute to the spread of an open flame.
   In addition, the material has the ability to self-extinguish, since when melted it is released from the cells carbon dioxide, reducing the oxygen concentration at the fire site.

1. Lifetime. Research shows that polyurethane foam is guaranteed to retain all technical characteristics and performance properties for at least 50 years.
   And if the installation technology is followed, the insulating layer will last as long as the rafter structure of the enclosing walls of the attic itself.
2. Environmentally friendly. The level of emission of harmful chemicals after application and hardening of polyurethane foam does not exceed those specified regulatory documents quantities .

Despite the high cost of not only the material, but also the installation services, polyurethane foam is often used for thermal insulation of attics, as it has many positive properties:

1. High adhesion to any surfaces. When sprayed from a mounting gun, polyurethane foam adheres to any surface, regardless of their porosity, roughness, temperature, slope, and so on. Therefore, you can spray foam directly onto rafter system roofs, without the use of additional fasteners.
2. Simplicity and speed of application. Thanks to the installation procedure mentioned above, the time required to process the room is minimized. Usually, it is possible to insulate a medium (and even large) attic within one working day. But for this it is necessary to have the necessary equipment, the purchase or rental of which is quite expensive.
3. Multifunctionality. The material not only plays the role of an effective heat insulator, but also protects the attic rafter system from the destructive effects of moisture and cold.

But, as in all other cases, only you will have to decide whether to use polyurethane foam. Although I personally see no reason to abandon the described insulation technology.

Summary

Now you know about everyone technical specifications popular materials and you can make an informed choice yourself. The video in this article, presented below, tells how to insulate an attic from the inside with your own hands using mineral wool.

What insulation did you choose? You can post your answers in the comments to the material.

September 7, 2016

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The modern building materials market is replete with a variety of insulating materials. But when the question concerns complete thermal insulation for a home, you need to know the main requirements for insulating materials. In this article we will tell you which insulation for the attic is better and what characteristics of the material need to be taken into account to keep your home warm and cozy in winter.

Your insulation should be durable and immune to external factors

Any builder with experience in roofing works, will tell you that the roof of the house must be well insulated. When choosing a material, focus primarily on the characteristics and needs of the structure. We live in a temperate climate, characteristics which is hot in the summer and severe frost in the winter. This means that your insulation must be durable and impervious to external factors.

One of the key criteria in choosing is the thickness of the attic insulation, on which the reliability and durability of the structure depends. For cold northern regions, you will have to choose thermal insulators as thick as possible, but for residents southern regions, where in winter the air temperature does not drop much below zero, you can choose those that are thinner and lighter.

Video about attic insulation

Most universal insulation- based on mineral wool. It is relatively inexpensive, but is suitable for almost any weather conditions. Although in some cases it is worth using polyurethane or other more expensive material that can fill the empty space more tightly.

We do not recommend using backfill insulation for roof insulation. Its thermal conductivity is quite high, which is why it simply cannot fully protect your home from the cold. It is much better to choose a roll or slab insulation for mansard roofs with low thermal conductivity.

Manufacturers, as a rule, set their own recommendations for laying insulation. If you follow them, you can significantly increase the service life and reliability of the structure. All available on this moment materials differ in the way they are laid depending on their weight, appearance and other characteristics.

It is best to choose insulation materials that weigh little, but are quite strong and rigid. You also need to remember the density of the material.

It is best to choose insulation materials that weigh little, but are quite strong and rigid.

In our climate zone, snowfalls are very frequent in winter, so it is necessary to take into account the load from the snow cover. Heavy weight on the roof can lead to significant deformation. As a result, thermal insulation is greatly deteriorated. As a result, you will have to do the home insulation work all over again. And this is not only a big waste of time, but also money.

You also need to take into account the slope of your roof. The smaller the angle, the more snow will accumulate on it in winter, and during rain, the greater the likelihood of leakage.

The roof is one of the most important structures in a house. We advise you to make the choice of material strictly according to the following criteria:

• Expect that there may be severe frosts in winter. The thermal insulation layer must withstand them. When a sudden change in temperature occurs, the material should not distort, crack or sag.
• Take moisture resistance and fire safety indicators seriously. Even when directly exposed to fire, it should not ignite. Today on the construction market you can find materials with fire retardants that prevent combustion and slow down the spread of fire. We strongly recommend using these. If we talk about the dangers of moisture, then when the insulation is saturated with water, its properties are greatly deteriorated. Water itself is an excellent conductor of temperatures, so wet insulation simply will not perform its functions. In addition, when the material gets wet, it becomes heavily deformed and gains weight, and the entire roof structure comes under heavy load.
• The selected insulation should keep its shape as efficiently as possible. It is better that the material is complete, without unnecessary seams, than to insulate the attic roof of the house with piecemeal remains in order to save money. Make sure you don’t have to pay twice - such material will not be able to fully perform its functions and even the most beautiful room it will be uncomfortable in the attic due to blowing air from under the roof.

The selected insulation should keep its shape as efficiently as possible.

There are really a lot of materials on the market. Among the most popular are fiberglass, mineral wool and polystyrene boards. But they are already quite outdated. We do not recommend using them. Today, much better quality products and liquids are being created that tightly fill voids and insulate the room from the cold.

Mainly heat loss during use modern means decreases by 50% or more. In addition, this allows you to save on other materials. For example, foam glass is extremely resistant to moisture, which eliminates the need to apply a layer of waterproofing. Foam glass is also characterized by very low thermal conductivity and impermeability to vapor particles. But let's consider other options.

Video about the process of attic insulation

• Polyurethane. It is sold in a liquid state, but when you apply it to a surface, it hardens and becomes very durable. As with foam glass, waterproofing is also not required. It is very convenient for attics with a complex structure, where it is almost impossible to work with standard materials. All empty space is completely filled with foam, ensuring low thermal conductivity. Excellent performance properties, long service life and overall ease of application - distinctive features modern polyurethane. The polyurethane board is blown out using a special machine and waited until it hardens. It's easy even without construction experience.
• Ecowool. One of its main advantages is environmental friendliness. It is made from exclusively natural materials. It's basically just regular cellulose. In addition, many manufacturers add fire retardants and active antiseptics to the material, which makes ecowool protected from fungus and mold. And it must be said that in comparison with other materials it costs an order of magnitude cheaper. Even a layer of 20 cm can cope with the worst weather conditions. If you can’t decide how best to insulate the attic from the inside, then this is one of the most affordable and practical options. When you use ecowool, it must be precisely adjusted to the size of the compartments between the rafters. It is laid in two layers for better heat conservation. But do not forget that it is sensitive to moisture, which is why a waterproofing layer must be installed.
• Polystyrene and other hard materials. Working with them is somewhat more problematic. They need to be laid on a sheathing or rafter structure. But when blown in correctly, it is polystyrene that provides the best thermal insulation for the attic.

When blown in correctly, it is polystyrene that provides the best thermal insulation of the attic

Remember that improper thermal insulation can cause many additional problems - roof icing, icicles, etc. Therefore, it is very important not only to choose the right way to insulate the attic from the inside and outside, but also to correctly carry out all the work on installing thermal insulation.