Insulation for the attic roof. Ways to insulate the inside of the attic

23.06.2020

The arrangement of the attic with a competent approach solves the problem of the shortage of living space in a residential building. But in order to use the premises under the roof all season, high-quality thermal insulation is required, especially if the construction site is located in central Russia or even further north.

The building materials market offers traditional and new ways to solve this problem. In order not to get lost in the abundance of materials, our article will tell you which insulation is best suited for a mansard roof and gable, how to choose and install it.

Heat exchange in the attic

Attic thermal insulation is a relatively new building technology that has become popular after heating has reached the under-roof spaces. In attics that are not heated, insulation is not so important.

After all, the air gap between the ceiling and the slopes covered with a snow cap perfectly retains heat in the living rooms. Installation of a heating system in the attic floor changes the situation in reverse side: heated air rises to the ridge, and gives off its heat to the roofing material, due to which the snow melts from the roof.

To reduce energy losses, it is necessary to provide for the insulation of the mansard roof and the gable in one of the popular ways:

Compared to insulation from the inside, the outside is worse protected from moisture. In addition, so that the weight of the roof, snow does not damage the integrity of the layer, materials that can keep their shape well are chosen for external thermal insulation.

General material requirements

Although the quality and method of installation to a certain extent affect the effectiveness of the insulation of the mansard roof and gable, the main thing is to correctly determine which material is best for this task. The builder argues that a good insulation should have the following qualities:

Resistance to external factors. It is important for the thermal insulation material to withstand sudden temperature changes, repeated cycles of defrosting, freezing, without cracking, without changing its shape and structure during the entire period of operation.
Low hygroscopicity. The insulation for the pediment and the roof of the attic has a low hygroscopicity, that is, it does not absorb moisture. Since an increase in humidity reduces the effectiveness of thermal insulation by half, increases the weight of the roof structure leads to the formation of mold and rot.
Low thermal conductivity. Materials with low thermal conductivity do not heat up and "seal" the heat from inside the room, reducing the cost of heating the attic.
Safety. For sheathing the pediment and the roof, a heater with a high fire safety class is used, non-combustible and non-combustible. In addition, it is better to use materials that are not harmful to health and do not cause allergies.

When deciding which material is better to use for roof insulation, please note that the layer thickness is selected depending on the climatic conditions in the construction region - for middle lane Russia is recommended to use heaters with a thickness of at least 150 mm.

Types of materials

Mineral thermal insulation materials

This category includes insulation with a fibrous structure, produced in the form of a roll or slabs, called mineral wool. They are made from waste glass industry, metallurgical production.

But for attic insulation, builders recommend stone wool based on basalt. Its operating temperature is 800-900 degrees, it does not burn and does not support combustion, it has high thermal and sound insulation characteristics.

Usually stone wool is used for, since the slabs, and especially rolls, have a fairly soft structure that collapses under weight roofing material.

The thermal conductivity of this type of insulation is 0.035-0.04 W / m, but during operation and accumulation of moisture, this value increases by half over 3 years of use. Therefore, for effective thermal insulation protection of mineral wool from moisture is required with the help of waterproofing and vapor barrier.

Polymer heat-insulating materials

Recently, builders have begun to widely use materials based on expanded polystyrene to insulate the pediment and roof from the outside or from the inside. This method has become the most popular method in the reconstruction of old residential buildings. It has the following performance features:

A light weight. Layers of insulation based on expanded polystyrene weigh a few grams, so they do not increase the load on truss system.
Low hygroscopicity. Expanded polystyrene absolutely does not absorb moisture, therefore it does not suffer from dampness, mold, does not lose its thermal insulation qualities during operation.
Does not conduct heat and sound. These properties make expanded polystyrene indispensable for houses located in the area of busy highways and buildings with resonant roofing materials (metal tiles, corrugated board), which increase noise during rain.
fire resistance. Styrofoam-based insulation does not burn, but melts slowly, therefore it is considered safe.
Ease of installation. A wide range of material thicknesses from 10 to 500 mm facilitates its use in self-assembly. Also, its installation does not require a special tool, and you can cut the layers with a knife or saw.

The only drawback of expanded polystyrene is fragility. During installation and operation, the sheets are easily damaged, crumble. But this problem is solved by the use of extruded polystyrene foam, which is blown with special equipment under the film between the roof rafters.

Natural thermal insulation materials

Those who primarily appreciate environmental safety, as well as the natural origin of materials, should take a closer look at natural roofing insulation. They are produced from the fibers of industrial crops - hemp, flax.

In addition to cellulose, ecowool contains 12% antiseptic and fungicidal additives and 7% fire inhibitors. Performance characteristics of natural heaters in comparison with mineral ones:

Low thermal conductivity. The thermal conductivity of ecowool is lower than that of mineral materials, they are 0.032 W / kg.
The absorbency of ecowool is two times less than that of mineral heat-insulating materials based on glass, basalt, and slag.
Flammability class G1-G2, that is, in terms of fire protection, ecowool is less safe than mineral-based heaters.
Ecowool has a looser structure than mineral wool, its density is 30-75 g / cu. m.
Natural types of thermal insulation materials absorb sound 10% better.

Experienced builders note that ecowool is the best material for insulating log, frame, timber houses with an attic, since its characteristics are close to those of natural wood, its application reduces heating costs by 30%.

thermal insulation residential attics The same indispensable condition for comfortable use as the organization of natural lighting and ventilation. Remember that it is much more convenient and more efficient to insulate the attic during construction than during operation.

Video instruction

Mansards are wooden structures made of partition walls adjacent to roof beams. Since the roof is made using pitched technology, an impressive space is formed under it, from which you can make a living space. The attic material, like the roof, does not have proper thermal insulation. She is also characterized by constant blowing, drafts. To make the room cozy, and living in it comfortable, you need to purchase a heater for the attic and perform a number of works on the attic sheathing.

Thanks to thermal insulation, a normal temperature for housing is maintained. Some materials can also provide sound insulation. By constructively improving the attic with a heater, you can kill two birds with one stone. But what is the best insulation 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.

Attic insulation requirements

The key criteria for choosing a material are its cost, durability and thermal insulation properties. A good heater should have the following qualities:

resistance to moisture;
frost resistance;
minimal hygroscopicity (the ability of the material to accumulate liquid in the structure);
ecological cleanliness;
no unpleasant odor;
fire safety;
water resistance;
minimal deformability;
thermal conductivity coefficient up to 0.04 W/m°C.

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 heaters are used that perfectly perform heat and sound insulation functions. These are:

mineral wool;
expanded polystyrene (aka polystyrene);
foam materials (for example, polyurethane foam);
insulation made from natural fibres.

In addition to structure, materials differ in price and complexity of handling. The following is a detailed discussion of each type of insulation.

Mineral wool

Outwardly resembling ordinary mineral wool, mineral wool is made from various breeds, and is available in the form of rigid plates or mats (soft sheets). There are three groups of insulation according to composition:

basalt (stone);
glass wool;
slag.

Basalt insulation is made from rocks of the gabbro-basalt group or marls (sedimentary rock of a clay-carbonate structure). For comparison: gabbro-diabase is often used in sauna heaters, because it perfectly retains heat and heats up quickly. Stone insulation has a vapor barrier of about 0.3 mg / m h Pa, and thermal conductivity is about 0.035-0.04 W / m ° C. Basalt wool fibers do not prick, which facilitates the work of lining the attic with them from the inside.

Glass wool consists of 1/5 of a mixture of soda, borax, limestone, sand, the rest is broken glass. The material is stronger, heavier than the basalt counterpart, and also has greater elasticity. Without problems withstands temperature fluctuations from -60 to +450 ° C.

The slag material has the same length and thickness as basalt, but slightly lower thermal conductivity. The fibers are quite sharp; this complicates the lining from the inside of the room. It also has high hygroscopicity. These shortcomings made the material the least popular among the representatives of mineral wool.

Each of the three types of material is an excellent sound insulator - insulation in the form of plates belongs to class "A" in terms of absorbing outside noise, and mats - to group "B". Often used as a fire barrier (not only in attics) because 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. However, the insulation is not without the following disadvantages:

hygroscopicity is higher than desired (it forces additional layers to be laid during sheathing from the inside - vapor and waterproofing);
irritates the skin (it is required to work only in clothes with long sleeves and wear gloves);
dusts profusely (a respirator is also desirable);
stands above other materials with similar properties.

There are negative sides, however, in terms of demand, mineral wool is inferior only to expanded polystyrene, better known by a different name.

Styrofoam

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, which is usually 0.03 W / m ° C. At least because of this indicator, insulation is preferable to mineral wool.

If the numbers mean nothing, it is worth turning to the practical side. When sheathing the attic from the inside, to achieve the same temperature in the room, a much smaller amount of foam will be required than cotton wool. This achieves space savings and optimal resource costs.

The almost 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 of properties. 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 supporting beams of the roof does not increase regardless of the season.

Styrofoam for lining the attic or other rooms 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.

The following material is noteworthy for ease of use, which, when hardened, resembles foam, but is supplied in liquid form.

polyurethane foam

PPU is one of the highest quality roof insulation. This is achieved by the fact that it is applied to vertical and inclined surfaces from the inside in liquid form, and when hardened, it slightly increases in volume, effectively filling gaps or holes.

Not big weight, low coefficient of thermal conductivity comparable to polystyrene foam, resistance to extreme temperatures and other advantages put polyurethane foam on a par with mineral wool and polystyrene foam. The fact that polyurethane foam is difficult to apply to the inner sloping surface of the roof is just a delusion. Good adhesion of the material prevents complications.

After hardening, 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.

Work on the insulation of the attic roof from the inside of the PPU requires special equipment. Most offices that provide interior roofing services require 300-400 rubles (per 1 m2) for applying foam. It is easy to calculate how many extra thousand rubles can be given 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 sums to insulate the attic from the inside, PPU will be the best purchase option. Once having completed the work on applying the material to the inside of the roof, you can hope for 30-35 years comfortable temperature indoors.

Natural fiber materials

In Central and Eastern Europe, insulation made from flax, wood, hemp, fastened together with starch or polyester, has become widespread. There are products based on sawdust of a tree or seaweed. They are good, but not applicable for the attic, because they occupy a large volume. Russia learned about such heaters about a dozen years ago.

Natural materials have a capillary structure that allows evaporation or air masses to pass through. Their advantages include:

human safety;
fire resistance;
characteristics for noise and heat insulation are close to the properties of polyurethane foam, polystyrene, mineral wool;
do not dust and do not prick when sheathing from the inside;
self-regulation of the microclimate of the room;
no shrinkage;
long service life (more than half a century);
there is no need for special clothing when working.

Examples of natural heaters - Ecowool, Ecolen, 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);
polystyrene and polyurethane foam (1000-3000 per cubic meter);
natural insulation (the price reaches 10-15 thousand rubles per cubic meter).

If there is a sufficient amount of finance, it is recommended to insulate the attic from the inside with polystyrene foam or polyurethane foam. Cheaper material (cotton wool) is also good, only it will take longer to tinker with it.

Based on the characteristics of the materials used in attic sheathing listed above, the user can decide how best to insulate the attic and proceed with the implementation of plans. Each material is good in its own way, but science has not yet come up with an ideal one. Based on the wishes or possibilities, among dozens of types of heaters, you can choose the most acceptable one.

If the roof country house forms a spacious attic space, it can be used to expand the living space. The attic room can serve as a bedroom or an office, a sports room, a cinema or a billiard room. To use the extra space all year round, need good thermal insulation. Insulation of the attic does not require large material costs, especially since the work can be done by hand. It is only important to choose the right heat-insulating material and carry out the installation correctly.

Requirements for thermal insulation materials

The same technology that is used in construction is suitable for attic insulation. frame houses, however, increased requirements are imposed on materials and quality of work. The quality of the attic space thermal insulation will affect both the conditions for comfortable living and the durability of the roof. This is due to the fact that the walls of the attic room form gables and roof slopes - those surfaces that heat up the most in summer heat. In winter, on the contrary, blown by cold air currents, they cool down the fastest. If the thermal insulation is of poor quality, then the roof will let heat out. One should not think that the danger of such a situation lies in a banal increase in energy costs for heating the attic. Warm slopes will provoke snow melting, and this is fraught with many more serious troubles - from mechanical damage the top cover of the resulting ice until fungi and mold appear, destroying the roofing pie and the wooden structures of the truss system.

High-quality thermal insulation will make the attic comfortable for living both in the summer heat and in the winter cold

When choosing a material for attic insulation, it should be remembered that not only the thickness and number of layers of thermal insulation, but also the ease of installation depends on this. Based on the specifics of the use of heaters, they are subject to the following requirements:

Ability to withstand peak temperatures. The material must be frost-resistant and not break down at high temperatures, retaining its characteristics even after numerous freeze-thaw or heating-cooling cycles.
Durability. The service life of thermal insulation should not be lower, if not higher, than other materials used on the roof. This is due to the fact that it is much more difficult to replace a roofing cake than, for example, a top coating made of metal tiles or ondulin.
As low a coefficient of thermal conductivity as possible. It is best to take a heater with an indicator of no more than 0.05 W / m × K.
Maximum moisture resistance. Since condensation may appear in the under-roof space, the material should not absorb moisture and lose its properties when wet.
Fire safety. Thermal insulation must not burn or support combustion.
Light weight. The insulation should be lightweight so as not to create an increased load on the roof truss system. The total weight of the insulation can be determined by multiplying its density by the volume. Experts recommend using materials with a density of up to 50 kg / m 3.
The ability to maintain a given configuration. The insulation is laid in the gaps between the rafters in an inclined position. If you choose a material that can deform under its own weight, then over time it can slide down, forming voids inside the structure. It is necessary to choose thermal insulation that can long time keep the original size and shape.

What thermal insulation will be chosen affects the thickness of the roofing pie. Later we will look at how to calculate the amount of material needed.

What materials are suitable for attic insulation

You can make the attic suitable for living at any time of the year with the help of various heaters. Consider their features and highlight the strengths and weaknesses.

Mineral wool

To insulate the attic, you can use glass wool, mineral or slag wool. These materials have the following thermal and operational parameters:

high thermal resistance - up to 1.19 W / (m 2 / K);
low thermal conductivity - no more than 0.042 W / m × K;
light weight - from 15 to 38 kg per 1 m 2.

Cotton-type thermal insulation is a favorite option for home craftsmen if the roofing cake needs to be equipped from the inside of the room. It does not support combustion, has a minimum weight, and, importantly, rodents do not start in its layer. Slab samples perfectly retain their shape, and when laying fibrous insulation in the space between the rafters, no precise adjustment is required - mineral wool is easily distributed without seams and gaps.

Mineral wool produced in the form of rolls and slab materials

The only drawback can be considered increased hygroscopicity. Due to the appearance of moisture between the fibers, the thermal insulation properties of the material fall by more than half, and it itself begins to collapse. Therefore, mineral wool needs high-quality waterproofing from the side of the roof and the installation of a vapor barrier membrane from inside the attic room.

Polymer thermal insulation

Often used to insulate roof structures. polymer materials- expanded polystyrene and polyurethane foam. They perfectly retain heat and, due to their hydrophobicity, are not at all afraid of moisture.

Simple expanded polystyrene, which is also called polystyrene foam, is one of the most popular heaters on the building materials market. Good performance characteristics- minimum density, low thermal conductivity, moisture resistance and the ability to hold a given shape contribute to the idealization of this material. As a result, it is often used where it is strongly discouraged. Firstly, only non-combustible polystyrene of the G1-G2 brand is suitable for insulation of residential premises, and not the popular G3-G4, which ignites perfectly and burns out in a matter of minutes. If you choose the latter for warming the attic, then it will be unrealistic to survive in it during a fire. Secondly, the installation of ordinary polystyrene foam is not an easy task, since it is poorly cut and crumbles easily. Thirdly, this material is subject to aging and begins to deteriorate rapidly over time. And in conclusion, it should be noted that the foam is a favorite material for rats and mice, so it is used only where it will be covered with a layer concrete screed or hidden behind plaster.

Styrofoam is a type of gas-filled plastic that can be used to insulate an attic room.

The disadvantages of polystyrene are almost completely devoid of extruded polystyrene foam (EPS), which is well suited for thermal insulation of an attic room from the outside. To do this, the insulation boards are laid directly under the roofing material, on top of the elements of the truss system. The composition of extruded polystyrene foam includes flame retardants, so it does not burn well. Compared to foam, XPS has higher strength and stiffness, which makes it much easier to install. Like other polymeric materials, extruded polystyrene foam is waterproof, impervious to steam and has good energy-saving properties. This makes it the best option for insulating a mansard roof from the outside. By the way, EPPS will require quite a bit - a 100-mm layer will be enough to insulate the attic in most regions of our country.

Extruded polystyrene foam is best suited for roof insulation from the outside

polyurethane foam

Polyurethane foam (PPU) is a gas-filled plastic that is applied in liquid form to inner surface stingrays. When set, the material forms a rigid foam with excellent physical characteristics:

heat transfer - up to 0.027 W/m×K;
thermal resistance from 1.85 to 9.25 W/(m2/K);
thermal insulation density - from 30 to 86 kg / m 3;
weight - from 11 to 22 kg.

For the application of polyurethane foam, a special installation is used, in which the liquid mixture is foamed when air or CO 2 is supplied.

To insulate the roof with polyurethane foam, you will have to turn to specialists - you cannot do without special equipment and skills

This method of installation largely determines the advantages of the insulation, since when blowing out the under-roof space, there are no cracks, gaps and cold bridges in the form of open elements of the truss system. PPU does not support combustion and does not change shape. It does not break down over time and resists moisture well. By the way, the last factor causes low vapor permeability - the insulation does not allow the roof to "breathe", which is fraught with high humidity in the attic space.

In order for the air in the attic room to be fresh and light, and the wall surfaces not to be covered with mold and fungus, when insulating the roof with polyurethane foam, you should definitely consider a high-quality ventilation system.

Ecowool can be considered one of the best materials for home insulation work. This insulation is more than 80% cellulose fibers, therefore it has a low thermal conductivity and is well suited for filling the gaps between the rafters. Since cellulose in its pure form burns well and is destroyed by fungi, borax is introduced into its composition as a flame retardant and boric acid to protect against damage by biological organisms, including rodents.

The main physical properties of ecowool:

thermal conductivity - from 0.037 to 0.042 W/m×K;
density depends on the degree of laying and varies between 26–95 kg / m 3;
combustibility - group G2 according to GOST 30244;
vapor permeability - up to 03 mg / mchPa.

In terms of its operational properties, ecowool approaches mineral and polymer thermal insulation, surpassing them in many factors. So, unlike mineral wool, it absorbs moisture without a significant decrease in thermal conductivity. With an increase in humidity by 1%, a basalt slab will lose a tenth of its thermal insulation properties, while ecowool, when saturated with moisture up to 25%, will increase thermal conductivity by no more than 5%.

Ecowool is suitable for attic insulation in the form of plates of various thicknesses.

It is also important that when dried, cellulose insulation completely restores its original characteristics. At the same time, it can serve as a kind of buffer that can maintain a comfortable level of humidity in the room. Ecowool allows installation in a seamless way, therefore it forms a monolithic layer without gaps and cold bridges. Its breathability is almost two times lower than that of mineral heaters, and at the same time it remains elastic enough to dampen sound waves. When using ecowool, the attic will be best protected from external noise. And, finally, it is impossible to remain silent about the environmental friendliness and safety of this material. In its composition there is not a single chemical compound that could evaporate and release substances harmful to humans.

How to calculate the thickness of thermal insulation

To calculate which layer of insulation is needed to insulate the attic, builders use the formula from SNiP II-3–79 δ ut = (R - 0.16 - δ 1 / λ 1 - δ 2 / λ 2 - δ i / λ i) × λ ut, in which R is the thermal resistance of a slope, wall or floor (m 2 × ° С / W), δ is the calculated thickness of individual structural elements in meters, and λ is the thermal conductivity of the insulation (W / m × ° С) for used structural layers.

In a private house building, the formula is simplified to a simple equation δ ut = R × λB, where the last factor characterizes the thermal conductivity of the insulation used in W / m × ° С. The minimum thermal resistance of walls, roofs and ceilings depends on the region in which the construction is being carried out.

Table: thermal resistance values depending on the region of construction

Town	R (m 2 × ° C / W)
Town	For floors	for walls	For coatings
Anadyr	6,39	4,89	7,19
Biysk	4,65	3,55	5,25
Bryansk	3,92	2,97	4,45
Velikiy Novgorod	4,04	3,06	4,58
Derbent	2,91	2,19	3,33
Yekaterinburg	4,6	3,5	5,19
Irkutsk	4,94	3,76	5,58
Kaliningrad	3,58	2,71	2,08
Krasnoyarsk	4,71	3,59	5,33
Maykop	3,1	2,8	3,5
Moscow	4,15	3,15	4,7
Murmansk	4,82	3,68	5,45
Nalchik	3,7	2,8	4,2
Naryan-Mar	5,28	4,03	5,96
Nizhny Tagil	4,7	3,56	5,3
Omsk	4,83	3,68	5,45
Orenburg	4,49	3,41	5,08
Permian	5,08	3,41	4,49
Penza	4,15	3,15	4,7
Saint Petersburg	4,04	3,06	4,58
Saratov	4,15	3,15	4,7
Sochi	2,6	1,83	2,95
Surgut	5,28	4,03	5,95
Tomsk	4,83	3,68	5,45
Tyumen	4,6	3,5	5,2
Ulan-Ude	5,05	3,85	5,7
Chelyabinsk	4,49	3,41	5,08
Chita	5,27	4,02	5,9

The thermal conductivity characteristics of any thermal insulation material can also be found in the tables.

Table: thermal conductivity coefficients of materials

To determine the thickness of the insulation, it is not necessary to count everything manually. You can use the online calculator, which is easy to find on the Internet. All that is needed in this case is to enter the values climate zone, attic area, type of insulation and its scope. The program will do all the other calculations for you.

Attic insulation from the inside

The simplest and most convenient way to insulate the roof is thermal insulation from the side of the attic room. For this purpose, almost all known thermal insulation materials. Most often, mineral or glass wool is used - it affects low price these heaters. Extruded polystyrene foam is used a little less often, the installation of which causes more difficulties. And unfortunately, ecowool or polystyrene blowing is still very rarely used - the relatively high price and complexity of installing thermal insulation play a role here.

When insulating the attic from the inside, not only the walls, but also the floor are insulated

The durability of the materials used and the comfort inside the attic depends on how accurately the technology of thermal insulation measures will be observed. The most important role here is played by how correctly the roofing “pie” is laid. If we consider the structure from the inside out, then it consists of the following elements:

finishing with sheets of drywall, plywood or OSB, clapboard, etc.;
vapor barrier;
thermal insulation material;
waterproofing;
counter-lattice and crate with a ventilation gap;
roofing material.

It should be noted that vapor barrier is needed only when cotton materials are used for insulation - in this case, it will prevent the penetration of moist air from the attic room. When using polyurethane foam or expanded polystyrene, the need for a diffusion membrane is eliminated.

As for waterproofing, it is needed in any case, since it will serve as an additional barrier to protect the roofing pie and wooden elements truss system from moisture coming from outside. If fibrous insulation is used for thermal insulation, then superdiffusion membranes are used that can pass water vapor in one direction. During installation, they are oriented in such a way as to ensure the removal of moisture from wadded materials. In addition, to improve ventilation between the waterproofing and the roof, a ventilation gap of 5 to 10 cm in height is arranged.

When insulating with mineral wool, it is necessary to use a vapor barrier film

The whole process of roof insulation can be divided into several stages:

preparatory work;
preparation of thermal insulation material;
laying the heater in place;
fastening of thermal insulation;
finishing activities.

The insulation of the attic should be remembered from the design stage, not forgetting to take into account the peculiarities of thermal insulation work at all stages of construction. It should be decided from the very beginning what the walls of the attic will be. If sloping roof surfaces up to the floor itself act as their quality, then the roof slopes are insulated. In the event that vertical wall structures are installed, thermal insulation is installed on the involved sections of the roof, walls and adjacent sections of the ceiling.

Thermal insulation is installed on the used areas

Work order

Before proceeding with the thermal insulation of the attic, the insulation pie should be protected with a layer of waterproofing. This work must be done before laying the roofing material, otherwise it will not be possible to achieve complete tightness of the heat-insulating carpet. Laying the film membrane begins right on top of the rafters. The work is carried out from the bottom up, with an overlap of the previous canvas by 15 cm and gluing the joint with special adhesive tape. It is not necessary to stretch the film, it is better to leave a little slack. Deflection up to 20 mm per 1 running meter there will be enough material so that the membrane waterproofing does not break with the onset of winter frosts. For attaching the film to the rafters, it is best to use construction stapler. If such a tool is not at hand, then the waterproofing can be nailed with galvanized nails with wide hats.

You should think about protecting the thermal insulation cake from moisture even at the stage of roof construction.

To ensure normal ventilation of the space between the film membrane and the roofing material, lumber with a thickness of at least 25 mm is used as a lathing. They are attached to the rafter legs using corrosion-resistant self-tapping screws or galvanized nails 50–70 mm long.

To avoid accidental damage to the waterproofing film, holes in the crate are made in advance.

If the roof is covered with a soft roof, then a solid base of particle boards, OSB or moisture resistant plywood. Metal tiles, slate and other hard roofing materials are attached directly to the elements of the crate.

Then the installation is carried out from the side of the attic. In order not to make mistakes, you should follow the order of work:

Thermal insulation material is unpacked. Plate and roll insulation is laid out on a flat surface and left for a short time to straighten its fibers.
The mineral wool panel is cut into pieces, the width of which is 2–3 cm greater than the installation step of the rafter legs.
The standard width of roll insulation is 1.2 m, so for ease of installation, you should choose the same or halved distance between the rafters. In the latter case, the insulation is cut lengthwise, obtaining two canvases 0.6 m wide.
The cut insulation boards are laid in the gaps between the rafters. Initially, the thermal insulation will be held due to the “spread” installation, so each canvas is first pressed in the center, and then its edges are filled so that the insulation does not protrude beyond the rafters.
Mineral wool is covered with a vapor barrier membrane. As in the case of waterproofing, strips of material are laid horizontally, from the bottom up, with an overlap of at least 10 cm. The joints are glued with adhesive tape, and the film itself is attached to the rafters with staplers.
From lumber with a thickness of 2.5 cm, the lower crate is made. In the future, plasterboard structures or other finishing material will be attached to it.
The insulation layer is covered with a vapor barrier membrane, on top of which the battens are stuffed

Sometimes it is necessary to equip an insulated attic in a house with an already installed roof. In order not to dismantle the roofing material, the waterproofing membrane can be installed from the side of the room. To do this, wrap the rafters with a film, and the material itself is attached to the crate. The disadvantage of this solution is that the wooden roof structures remain unprotected if moisture begins to seep inside for some reason.

Video: thermal insulation of the attic floor with mineral wool

Features of insulation of the mansard roof from the outside

If the design of the attic presupposes the presence of wooden beams on the walls, or if its dimensions do not allow using a single centimeter of space, then the roof is insulated from the outside. It is best to do this at the stage of roof construction, because otherwise you will have to remove the roofing material.

Roof insulation from the outside can only be done with rigid thermal insulation.. The best material in this case is extruded polystyrene foam. As noted above, such a coating does not need vapor barrier, so the insulation pie consists of fewer layers:

slab thermal insulation;
waterproofing membrane;
crate with ventilation gap;
roofing material.

The main advantage of roof insulation from the outside is the uniformity of the thermal insulation layer. The undoubted advantage is the absence of cold bridges and the possibility of inspecting and repairing rafters without dismantling the roofing material.

The way in which the attic is insulated from the outside will increase the interior space of the attic and use the rafters as decorative elements interior

Work order:

All that remains to be done is to lay and fix the roofing material. Rigid types of coatings are attached directly to the crate, so you should take into account the distance between the timber at the stage of its installation. Under soft roof equip a solid base of OSB or plywood, which is protected by a layer of waterproofing. In this case, it is not necessary to install a waterproofing membrane over the insulation.

Video: everything you need to know about attic insulation

The thermal insulation of the attic room, in addition to, in fact, keeping the heat inside, allows you to solve a number of other problems. High-quality insulation will prevent overheating of the roof in the summer, which means that the room will be as comfortable as in any other room. V winter frosts the heat-insulating cake will not allow the melting of snow and the formation of ice, and during rain or hail it will serve as noise protection. It is only important to take into account the features of various heaters and perform the work competently, taking into account the rules and installation technology.

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The popularity of lofts 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 specialists. Why did the transfer of under-roof zones into housing stock become actual 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 an attic insulation that 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 under-roof space

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

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

More moisture enters the attic than the floor space. Water in the form of ascending vapor penetrates from below. The vapor barrier of the floor ceiling reduces the flow of moisture, but does not nullify it.

The second factor in air humidification is associated with the inevitable condensation on the lower surface of the tiles 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, a ventilated cold attic forms a buffer air cushion, effectively drying the roof from below. The absence of such a buffer in attics reduces natural ventilation wooden rafters and the insulation itself.

The location of thermal insulation directly under the roof slopes increases the intensity of heat transfer, so attic insulation should be more energy efficient than floor insulation between housing and a cold attic.

Criteria for the selection of insulating material

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

Terms of performance of thermal insulation works. Usually freshly 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 necessary after the installation of the roofing.
Choice of insulation thickness. The intensity of heat flows through the roof is much greater than the loss of energy through walls or foundations. The usual mineral wool thicknesses of 100 - 150 mm do 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 of building structures and materials of all layers of the sandwich. 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 heat-insulating 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 a housing stock, then an additional crate from the bottom of the rafters is usually used, increasing the installation height to accommodate the insulation layer.

To determine which insulation is best for your mansard 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 high vapor permeability of the insulation if you do not have time to dry the wood of the rafters.
Calculate the required insulation layer thickness for several options.
Make budget options. In this case, one should take into account the exclusion of a vapor barrier membrane from the composition of the sandwich in the case of using insulating materials with a hygroscopicity close to zero.

Types of insulation materials used for mansard roof insulation

First of all, it should be noted that it is not only inconvenient, but also impractical to insulate inclined surfaces with bulk materials, since the fragments rolling down 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 conduct 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 included 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 a regular roll isover that we use for walls work? 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: ROCKMIN PLUS mineral wool, Izover Pitched Roof and other brands, in the names of which there is a direct indication of the field of application that suits us.

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

Of 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 (0.024 W / m * K).

Heaters with the highest energy efficiency

Manufacturers of building thermal insulation have developed grades of extruded polystyrene foam (EPS) boards, specially designed for arranging attics and roofs of cold attics. These are Penoplex Pitched Roof, TechnoNIKOL Carbon Solid and other materials with a thermal conductivity coefficient of not more than 0.030 - 0.034 W / m * K. The brands are distinguished by the ability to order panels of increased length (up to 4.5 m), which significantly speeds up installation work.

XPS is a combustible 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 XPS, the foil can significantly increase the fire resistance of the sandwich.

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

Heaters with high specific noise absorption

Insulation with Zhivoizol - linen heat insulator

The soundproofing properties of mansard roof insulation can be very relevant when using metal tiles, which amplify the noise of natural precipitation. Currently developed board materials, characterized by a high noise reduction coefficient with a slight 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". Plates made of this material absorb noise in all frequency spectra 20% - 30% more efficiently than mineral wool and XPS.

Conclusion

The choice of insulation for the attic roof should be carried out in parallel with the development of roof trusses and the design of the entire sandwich, which includes roof cladding, membranes and battens. When converting cold attics into housing stock, it is relevant to minimize the thickness of the insulating layer and use insulators with the lowest thermal conductivity.

The wrong choice of insulation, or its insufficient thickness, leads not only to cold in the attic room. Even if you compensate for the low temperature with intensive heating, you may encounter:

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

Thus, the competent design of a roofing sandwich for attics is important not only for providing comfort to residents, but also in terms of increasing the life of the building.

Video on the topic: how to properly insulate the attic

The question of which insulation is best for the attic is relevant for those who decide to equip a living space under a high pitched roof of a private house. The attic differs from the usual room of the house in 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 a heater for the attic

High-quality insulation allows you to make the attic suitable for year-round use. When choosing a heat insulator, it is necessary to pay attention to the performance characteristics of the materials, including comparing:

soundproofing 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 evaluated 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, roofs and floors, the insulation of all structures will last the same period.

Soundproofing properties are a particularly important parameter if the roofing is made of metal (folded roof, metal tiles, corrugated board). Gusts of wind, rain and hail make such a roof “sound”, and staying in the attic will cause discomfort.

Plate heaters well-known manufacturer

Since the roof frame is usually made of wood, it is desirable to use a fire-resistant and non-flammable insulation. Otherwise, an accidental fire will lead to the fact that the entire attic and roof will quickly be engulfed in fire.

So that condensation does not form on the wooden structures of the truss system and gables and the insulation does not lose its thermal insulation properties due to moisture penetration, it is necessary to insulate the attic room with vapor and moisture-proof material, or use reliable hydro and vapor barrier. This affects the speed and complexity of the installation of the insulating layer, affects the preferences when choosing a material.

Insulation thickness

Table 1. The dependence of the thickness of the insulation on the coefficient of thermal conductivity

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. Thermal conductivity coefficients of some heaters

Polyurethane foam and ecowool - modern materials, which can be used as a heat insulator for attic rooms, but their installation requires the use of specialized equipment, the invitation of specialists. The rest of the popular heat insulators are available 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 laths of the lathing on the walls) and inserted by surprise. If the calculated thickness of the heat-insulating layer exceeds the width of the rafter leg, bars of a suitable section are stuffed onto the rafters from the side of the room.

Two-layer insulation is considered the most effective - after the gaps between the rafters are filled with a heat insulator, another layer of roll material (possible with a foil vapor barrier outer surface) is attached over the rafters with continuous joined strips. This will prevent the formation of cold bridges.

Laying a heat insulator between the rafters

Let us consider in more detail the main pros and cons of popular heaters that are suitable for thermal insulation of the attic roof and gables.

Fibrous roll and plate heaters

glass wool;
mineral wool;
stone (basalt) wool.

Their key advantage and at the same time a disadvantage is the ability to pass steam. Theoretically, moist warm air from the attic will escape through the breathable inner lining, heat insulator and roofing system, which will help maintain a favorable microclimate in the room. In practice, there are the following difficulties:

an increase in the moisture content of the fibrous insulation leads to a sharp decrease in its thermal insulation properties;
the insulation that has accumulated moisture (especially glass wool) is crushed, 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. A waterproofing material must be laid between the roofing and thermal insulation.

Roofing pie with waterproofing over insulation

Air exchange through fibrous insulation will be carried out only if the waterproofing and vapor barrier layer is made of special gas-permeable membranes. The vapor barrier must allow air to pass through, but retain moisture coming 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 ordinary or reinforced film, roofing felt or glassine. But these investments will justify themselves due to the durability of not only insulation, but also the roof truss system.

Super diffusion membrane

If a film is used as a vapor barrier, this will reduce the cost of construction, but this will nullify an important advantage of fibrous insulation - gas permeability. Perforated film should not be used, as it allows steam to pass through, which will accumulate in the insulation.

Performance characteristics of fibrous insulation

glass wool. To her positive qualities can be attributed:

fire safety (2nd degree of fire resistance);
environmental safety (does not contain resins);
unattractive for mice (do not build nests and moves);
affordable price.

The main disadvantage is that when working with the material, sharp glass dust is formed, the installation of a heat insulator requires accuracy and the use of protective equipment. In addition, over time, glass wool tends to deform, wrinkle, especially when moisture penetrates.

Mineral wool. The composition of the material includes fibers of various origins (production material - clay, stone, quartz sand, glass, etc.). Mineral wool is characterized by a multilayer inhomogeneous structure with air lenses. Due to this, the material dampens sound waves well. Mineral wool (primarily Isover, Ursa) is recommended for those who decide to make metal roofing.

Such a heat insulator is fire resistant, does not rot, and is easy to install. But rodents can settle in it, whose nests, passages and waste products reduce the performance properties of the insulation.

Basalt wool. Consists of fibers obtained by melting rock. Withstands heat up to 1000 degrees, does not spread combustion. Basalt wool should be chosen carefully, checking quality and safety certificates: some manufacturers, in an effort to reduce the cost of products, use resins that emit toxic substances.

Basalt wool

Basalt wool is resistant to fungus, but can be damaged by rodents. This is a good sound insulator, easy to install. But when choosing a material for insulating the truss 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 shape even during prolonged use. For mineral, basalt wool, the density index should be about 40-45 kg / m3.

Polymer materials for insulation

We choose a polymer heat insulator for the roof and walls of the attic. This can be foam, extruded polystyrene foam (these two types of insulation are available in the form of sheets and plates of various 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 thermal insulation will not overload the truss system and will successfully cope with the task of retaining heat.

The disadvantages of polymer insulation include extremely low vapor permeability. Gas exchange is not carried out through insulated structures, therefore, one cannot do without a well-thought-out ventilation system in the attic room.

Attic insulation with polyurethane foam

Thermal insulation made of extruded polystyrene (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 dangerous for wood will not condense.

All joints and junctions of thermal insulation made of foam plastic must be filled with mounting 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 losses are 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 mount the insulation according to the same principle as fibrous plate materials. Unlike extruded polystyrene foam with a solid closed cell structure, the foam consists of many individual pellets compressed into a board. Technological pores remain between the structural elements, which are able to pass steam to wooden structures.

A suitable foam density is 35 kg/m3, the material must not crumble into individual balls when broken. Since foam plastic smolders when ignited, releasing toxic substances and mice easily gnaw through it, this is not the best material for internal insulation.

Polymer insulation for the attic should not be considered as a soundproofing material for the roof - it will not save you from the sound of raindrops. 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 selected insulation option will last for many years if you purchase good material and take into account all the subtleties of its installation.