Ways to insulate wooden beams of the attic floor. Why insulate attic floors? Attic floor insulation options

The roof protects various buildings and structures from rain and wind. The attic under the roof serves as a boundary between the warm air from the house and the cold environment. To reduce the outflow of heat from the heated room to the outside, thermal insulation of the attic space is used.

Why insulate?

For comfortable living conditions in winter, houses are heated, consuming a huge amount of heat carriers. Every year the cost of heating only increases. In order to save costs and reduce heat loss, energy-saving double-glazed windows are installed and the walls, floor and ceiling are insulated with heat-insulating materials.

More than a third of the heat from the house comes out through the roof as warm air rises. Through an uninsulated ceiling, warm streams leave the living quarters and rush to the attic, where, in contact with the roof covering, they form condensate on the floor beams and the rafter system. High humidity leads to deterioration of the material and the reproduction of fungi, reducing the durability of the roof structure.

If the attic space is actively used or serves as an attic, then the roof itself is insulated. When the attic is not in use, the attic floor is insulated. Installation is carried out on the beams of a cold attic.

In this case, you can achieve the multifunctionality of the heater:

protection from hot hot air in the attic in the summer allows the living space to remain cool;
sound absorption function: noise from howling wind and precipitation is reduced;
retention of warm air indoors during the heating season is achieved by creating an insulating barrier.

The use of various types of insulation will reduce the level of heat loss by 20%, which will extend the life of the roof without repair and replacement of wooden elements.

Types of attic floors

Depending on the location, the floors are divided into interfloor, attic, basement or basement. To create a ceiling and floor in buildings, load-bearing elements are constructed, consisting of beams and slabs. Reinforced concrete slabs, steel and wooden beams are used as attic floors. When erecting brick and panel high-rise buildings, reinforced concrete floors are used. Beam ceiling is used in low-rise construction. On wooden beams there is a beam, logs and boards of large section, laid on load-bearing walls.

Each type of flooring, wooden or concrete, has its own advantages and disadvantages. Reinforced concrete floors are durable and fire resistant, but difficult to install and require increased wall strength during construction. Wooden floors have a lower load on load-bearing walls, are suitable for construction with any type of building materials, they are mounted without the involvement of construction equipment. The disadvantage of wood is its fire hazard, so wooden structures need additional treatment with flame retardant impregnations.

Whatever material the attic floor is made of, it is necessary to carry out thermal insulation work, since the thermal conductivity of concrete and wood is high. The insulation scheme consists of a vapor barrier, the insulation material itself and waterproofing, forming a layered cake that helps to perform a protective function for the roof and heated rooms.

Attic floors, which serve for multi-level division of premises, must meet certain characteristics:

Strength. Ceilings must withstand heavy loads.
Fire resistance. The limit of resistance to fire is regulated by technical requirements. It is different for all materials: concrete withstands 1 hour, and untreated wood - 5 minutes.

Variety of materials

Before choosing a material for insulation, you need to understand the variety of heat insulators produced, taking into account their main properties and characteristics. According to the type of laying, thermal insulation products are divided into: rolled, bulk and slab.

Rolled

Mineral wool is produced in the form of soft rolls. This fibrous material comes in three varieties - stone wool, glass wool and slag wool. For raw materials in the production of stone wool are alloys of rocks. Glass wool is produced from sand, dolomite and glass waste. For slag wool, metallurgy waste is used - slag. Attics are insulated with basalt and glass wool.

Mineral wool has the following advantages:

do not burn, melt at high temperatures;
rodents do not start;
available;
convenient for installation;
have a low weight.

The negative point when using cotton wool is its hygroscopicity and low environmental friendliness. Cotton wool absorbs water well, reducing its thermal insulation qualities. When laying glass wool, you must follow safety rules and use personal protective equipment. The environmental friendliness of the material is low, since phenol-formaldehydes, which are harmful to human health, are used in the production of mineral wool.

To prevent moisture from penetrating into the wool, it is necessary to strictly observe the laying technology with vapor barrier films and a waterproofing layer, leaving gaps for ventilation. With proper insulation with mineral wool and compliance with all technical requirements, it is possible to achieve an economical and high-quality heat-insulating layer.

Rolled polyethylene foam, or isolon, is used for complex thermal insulation and as a hydro vapor barrier. It is a foamed polyethylene 0.3-2.5 cm thick with a one-sided foil layer. Isolon has heat-removing, fire-resistant and hydrophobic qualities.

Bulk

In the form of fractions of different sizes, the following types of bulk heaters are used:

sawdust;
straw;
slag;
vermiculite;
expanded clay;
foam glass;
ecowool;
polyurethane foam.

Houses were insulated with sawdust for a long time, until modern heaters were launched into mass production. The main advantages of sawdust are high environmental friendliness due to the naturalness of raw materials, low weight and availability of material for a penny cost. The main disadvantage of sawdust is the combustibility of the material. Also, when moisture is absorbed, sawdust can become moldy. The sawdust layer is easily damaged by mice.

Straw insulation is a traditional rustic method of keeping the heat in the house. It is lightweight and affordable material. Due to the high thermal conductivity, the straw layer should be large - up to half a meter.

The downsides are obvious:

straw serves as a good habitat for rodents;
ignites quickly and burns well;
gets wet and rots;
caking, reducing the layer of insulation.

Slag is a raw material obtained from metallurgy waste. Slag pumice and blast-furnace slag has long been used as a cheap filling insulator. It is non-flammable, durable and cheap material.

As a result of swelling of mica, vermiculite is formed - a natural, lightweight, durable insulation. The thermal conductivity coefficient is comparable to mineral wool. Its adsorbing qualities allow not to install hydroprotection. Vermiculite is not affected by fire.

Expanded clay is a light clay granules. Natural mineral material is environmentally friendly, durable and non-combustible. Among the advantages of expanded clay insulation, it is worth noting the ease of installation - the granules simply scatter around the attic with a layer of the required thickness. In order to achieve reliable thermal protection in different regions, expanded clay is laid with a thickness of 20-40 cm. A large layer of expanded clay is heavy, so the possibility of loading on wooden floors is taken into account.

Foam glass refers to backfill low-heat-conducting heaters. In production, glass industry waste is foamed, obtaining a high-quality insulator. Foam glass differs in moisture resistance, durability, environmental friendliness and durability. The high cost of foam glass is a limitation for widespread use.

Ecowool is a modern cellulose insulation.

Advantages of using ecowool:

natural anti-allergic composition;
antipyretic substances give fire resistance;
when wet, does not lose thermal conductivity.

Polyurethane foam belongs to the category of bulk insulation. Polyurethane foam is a liquid plastic that does not need a vapor barrier and waterproofing. It has the lowest coefficient of thermal conductivity, giving high thermal insulation properties to a small thickness of insulation. The coating is applied in a continuous layer without seams, closing all the cracks. Water-repellent qualities do not allow fungi and bacteria to multiply in the attic space. Solidification strength does not give a chance to get rodents. Substances are added to the composition that give polyurethane fire resistance.

Polyurethane has only one drawback - the high price. This is due to the use of professional foam compression equipment. We have to resort to the help of specialized companies.

in slabs

Plates and mats of different sizes are produced:

Styrofoam;
extruded polystyrene foam;
mineral wool;
reeds;
seaweed.

Styrofoam boards are made up of polystyrene granules.

Polyfoam has the following features:

low thermal conductivity makes it an effective heat insulator;
very light, easy to install;
highly flammable, emits toxic substances when the temperature rises;
waterproof;
not resistant to mechanical stress;
The popularity of polystyrene foam is due to its low cost.

Extruded polystyrene foam is the same foam produced by extrusion. This allows you to save all the advantages of the foam, acquiring an increased density that can withstand heavy loads. Grooves are provided in the expanded polystyrene plates, which facilitates installation without gaps and creates a continuous coating.

One option for producing mineral wool is slabs, often coated on one side with reflective aluminum foil. The foil acts as a vapor barrier and reflects heat out of the house. The miniplate is convenient to use for self-assembly.

Reed mats and algae ladders are produced in the form of compressed briquettes. As raw materials, natural, natural, light materials are used - reeds and algae. High environmental and vapor-permeable properties allow them to be used for wooden buildings. The problem of fire safety is helped by the processing of raw materials with fire-resistant compounds.

How to choose?

When choosing thermal insulation materials, the type of overlap and the features of the insulation are taken into account. The characteristic qualities of a heat insulator become a decisive criterion.

A number of factors are taken into account:

thermal conductivity level. The best insulation has low thermal conductivity with a small layer thickness.
Fire resistance and frost resistance. The material must not ignite.
Ease of installation.
Durability. The insulation must be durable, not collapsing under the influence of adverse conditions.
Ecological purity. The more natural the composition of the material, the safer it is for human health.
Price. In private construction, price often becomes the main criterion.

Taking into account all the features of the material, you can choose the right insulation for the house. Often the most optimal choice is mineral wool insulation. Compliance with the installation instructions will allow you to perform high-quality thermal insulation work.

Calculation of the thickness of the insulation

In accordance with the requirements of SNiP for building insulation materials, the thickness of the insulation depends on the type of thermal insulation, the duration of heating and the average temperature in winter in a particular region.

The thickness of the insulation is calculated based on the thermal conductivity of a particular material. This indicator is indicated on the packaging of the purchased insulation. Moreover, they select the upper limit of the norm for a humid environment.

Features of the work

The type of overlap determines the peculiarity of thermal insulation work. Methods for laying thermal insulation differ depending on the type of insulation.

On reinforced concrete slabs

It is easy to insulate an attic with a reinforced concrete slab floor, since the attic floor is even. As a heater, mineral wool rolls, a slab version and any bulk varieties are suitable. The weight of the material can be ignored, since reinforced concrete slabs can withstand heavy loads.

Since the roof of a cold attic performs only the function of protection from rain, snow and, in part, wind, special attention should be paid to the thermal insulation of the floor. Insulation of the attic floor is carried out using various heat-insulating materials with the obligatory organization of wind protection, especially from the side of the eaves of the roof.

Insulation of the ceiling in two layers using mineral wool rolls

As a rule, insulation is laid directly on the floor of a cold attic. Naturally, provided that the attic will not be operated. This will save on a layer of waterproofing film, as well as on the organization of a full-fledged floor covering.

How to insulate the attic floor and what materials can be used for this - read below.

What should be the thickness of the attic floor insulation?

The thickness of the thermal insulation layer does not depend on which design of the attic floor on wooden beams or reinforced concrete is chosen. On the packaging of any insulation, the coefficient of thermal conductivity λ is indicated, and it has two values: λA - for a dry environment, and λB - for a wet one. The lower this coefficient, the better the insulating properties of the material. It is on the basis of this value that the calculation of the attic floor insulation is made.

The thickness of the attic floor insulation is:

α = R 0 λB

where R 0 is the coefficient of resistance to heat transfer, which, according to the standards, is 4.15 m² ° C / W.

Insulation of the attic floor on wooden beams

In most small houses and cottages with a cold roof, wooden floors are used, so it is their thermal insulation that we will consider first of all.

The device of the attic floor on wooden beams, as a rule, is as follows:

Bottom floor lining.
Vapor barrier.
Cover beams.
Insulation.
Waterproofing.
Finishing.

The installation of a ceiling in a private house with a cold attic begins with the laying of load-bearing beams. Since their maximum length is usually 4 meters, for rooms of greater width it is necessary either to build supports or use metal girders.

Scheme of a wooden attic floor with two layers of insulation

After the beams are laid, a vapor barrier is made for the ceiling of the cold attic. To do this, a vapor barrier film is attached to them from below, which protects the insulation from the penetration of moisture from the lower room. When you are insulating the wooden floor of the attic, it is advisable to use special reinforced multilayer materials made of polyethylene or polypropylene as a film, since it is stronger and much easier to attach.

It is best when the vapor barrier layer is continuous. However, the design of a wooden attic floor does not always allow this. If for some reason the vapor barrier cannot be placed under the beams, the film is laid between them with an overlap on them and fixed with a special adhesive tape to ensure tightness.

Don't forget to impregnate the wood

The device of a wooden attic floor involves the risk of damage to the supporting structures due to decay. Therefore, before laying the cold attic cake, all wooden beams and crates should be impregnated with special solutions that prevent rotting and mold formation.

Next, the attic floor is insulated along the beams, for which the heat-insulating material is laid between them. If you use loose insulation, then it should be carefully leveled and made sure that it fills all the voids.

The minimum thickness of thermal insulation for insulating an attic wooden floor, calculated by you using the formula above, may be greater than the width of the supporting beams. In this case, a crate of bars of the size you need is attached across them. Then another layer of insulation is laid between them with the obligatory overlap of the joints of the previous layer.

Avoid cold bridges

It is recommended to close the attic floor beams with a layer of thermal insulation even if their width is sufficient to accommodate the insulation of the calculated thickness. The fact is that so-called cold bridges are formed through them, in connection with which heat losses in the house increase.

Attic flooring on wooden beams is usually performed with a floor made of ordinary flooring made of processed boards laid across the battens or support beams. However, thick plywood, chipboard, MDF and other similar materials can also be used as a finish.

If you want to use a leveling screed as a finish, then waterproofing a cold attic over a layer of insulation is a must.

Insulation of the attic floor on a reinforced concrete slab

If you need to insulate the attic floor on reinforced concrete slabs, then this can be done in two ways: with and without the crate.

The first method is universal, but most often used for light types of insulation. The cold attic attic floor device in this case will look like this:

Attic floor vapor barrier in progress cold attic, which should cover the entire layer of insulation also from the sides. Since the vapor barrier simply needs to be laid on the floor, it is not necessary to use specialized materials for these purposes - an ordinary cheap plastic film will do.
On top of the film with a narrow side wooden block placed a width equal to half the required thickness, which the insulation for a cold attic should have. The distance between the bars is usually taken equal to the width of the roll or plate of the selected brand of insulation.
between boards insulation for the attic floor. If it is necessary to use several layers of heat-insulating material in thickness, it is laid with overlapping joints of the previous layer.
Across the already laid bars, exactly the same, at the same distance from each other. Between them, a second layer of thermal insulation of the attic floor is laid.
Above vapor-permeable waterproofing of a cold attic is laid, which is fixed either with a special adhesive tape or a thin bar nailed along the crate. This stage can be omitted if high-quality waterproofing of the cold roof from corrugated board has already been completed before.
across the bars nailed floor boards or walkways are laid for movement.

Since it is very important to properly insulate the ceiling under a cold roof in order to save on heating the house, I recommend using the above transverse thermal insulation laying scheme. Such an attic floor device minimizes the possibility of forming a cold bridge through wooden bars, since most of them will be insulated with a heater.

The second method of warming a cold attic on reinforced concrete slabs without the use of a crate is suitable in cases where moisture-resistant solid types of insulation are used for thermal insulation, which can withstand a significant load without loss of properties.

Scheme of the device for overlapping the attic on a reinforced concrete slab

In this case, the vapor barrier of the attic floor is also laid first. Next, the attic floor slabs are insulated with a layer of thermal insulation of the calculated thickness.

A leveling screed is poured over it. The finished floor is already laid on the screed. If the insulation of the concrete attic floor is carried out with aerated concrete and materials similar in density and properties, then you can do without hydro and vapor barrier, as well as screeds.

Insulation for the attic floor: which one to choose?

Before you insulate the attic floor, you need to choose a heat-insulating material that is right for you. Unfortunately, there is no universal option, the better to insulate the attic floor. This choice depends on many factors, the most significant of which are:

heat-insulating properties of the material;
fire safety;
price;
ease of installation;
environmental friendliness;
hygroscopicity;
strength;
resistance to decay, temperature, acid and alkali.

You must decide which of these factors are most important to you, and which can be neglected.

Insulation of the ceiling of a cold attic with mineral wool

Mineral wool is one of the most popular materials for floor insulation. The best characteristics for insulating the attic floor of a house are its variety based on basalt fibers, which is called stone (basalt) wool.

Insulation based on basalt fibers belongs to the class of non-combustible materials with a melting point above 1000 ° C; and has excellent thermal insulation properties. However, it easily absorbs moisture, so when using it, the requirements for hydro and vapor barrier are especially high.

Insulation of the attic floor with mineral wool is best done using rolls, since the joints between the plates, albeit not much, but reduce the effectiveness of thermal insulation. It must be laid close to the beams or guides, but avoiding jamming.

Mineral wool laid in two layers when insulating the attic floor

The installation of mineral wool is very simple, so this heat-insulating material is most often chosen when they want to insulate the attic floor with their own hands without involving specialists. During work, do not forget to use personal protective equipment: thick rubber gloves, goggles and clothing that covers the entire body. For people prone to allergies, this kit must be supplemented with a respirator.

Advantages:

fire safety;
Environmental friendliness;
Ease of use;
Relatively low price.

Flaws:

Tendency to form seals, good creasing;
Hygroscopicity.

Insulation of the attic floor with foam

Styrofoam is a very inexpensive material, which, in fact, is expanded polystyrene foam and retains heat due to these "bubbles" with air. It is cheap, has good thermal insulation properties, is moisture resistant and can withstand fairly large compressive loads.

Styrofoam boards of various thicknesses

However, all its advantages are more than covered by one drawback - this material is fire hazardous. Already at 80 °C; foam plastic melts with the release of a huge amount of harmful substances, and at a temperature of 210 ° C; ignition occurs. Therefore, insulating the attic floor over wooden beams with foam plastic is not a good idea. However, it can be used between non-combustible materials, for example, when laying as insulation on a concrete slab with a screed.

Advantages:

High heat-insulating properties;
Low price;
Moisture resistant;
Resistant to decay;

Flaws:

fragility;
Very combustible;
Deformed already at a temperature of 60 °C;
It is an excellent hiding place for mice.

Insulation of the attic floor with extruded polystyrene foam

Extruded (extruded) polystyrene foam is made from the same material as polystyrene, but using a fundamentally different technology. On the territory of the CIS, heaters of this type from the Penoplex company are most common. The performance properties of extruded polystyrene foam are much better than those of polystyrene, especially with regard to the ignition temperature of the material.

Extruded polystyrene foam in slabs of various thicknesses

However, the insulation of a wooden attic floor with foam plastic is still not recommended. Despite the fact that open combustion of this heat-insulating material occurs at a sufficiently high temperature, it is still a fire hazard. Firstly, extruded polystyrene foam supports combustion, and secondly, it releases very caustic and toxic substances when heated even to very low temperatures, and they are the cause of death in a fire in most cases. Therefore, penoplex is far from the best option than insulating the attic floor of a house, even if it is reinforced concrete.

Advantages:

High heat-insulating properties;
Moisture resistant;
Resistant to decay;
High density;
Withstands fairly large loads;
Light weight.

Flaws:

When heated above 80 °C; begins to release toxic substances;
Fire hazardous;
Deforms when heated.

Insulation of the attic floor of the house with polyurethane foam

Polyurethane foam slabs are one of the best insulation materials available. This material has excellent thermal insulation properties, it is durable, resistant to chemical and bacteriological influences, non-hygroscopic and fireproof.

Polyurethane foam insulation in the form of a plate with a foil coating

Polyurethane foam is the best way to insulate an attic floor in a private house. If you can afford it. It is the high cost that is its main and, probably, the only drawback. Because of it, it may even be difficult to purchase this material in small towns.

Advantages:

The best heat-insulating properties among the considered materials;
Fireproof;
Unaffected by moisture and chemicals;
Does not rot;
Eco-friendly;
Convenient to use.

Flaws:

Price.

Warming the ceiling of a cold attic with sawdust

Previously, in the absence of other materials, the insulation of a cold roof with sawdust was a ubiquitous phenomenon. Now this method of thermal insulation is used by those who like its environmental friendliness. At the same time, despite popular belief, the design of the attic floor with the use of such a heater is by no means cheap. Sawdust is not stacked “dry”, but in a special solution, the manufacture of which requires money and a lot of time.

The composition of the sawdust solution for warming a cold attic is as follows:

10 buckets of sawdust(we need exactly wood, which are formed during sawing and processing of wood, furniture sawdust - too small for these purposes);
1 bucket of hydrated lime(fluffs);
1 bucket of cement;
5-10 buckets of water with antiseptic, for example, with boric acid, soap or blue vitriol (fill in gradually with a watering can, the total amount depends on the size of the sawdust).

The resulting mixture is placed on the base between the beams and rammed. The thickness of the layer of such insulation for the attic floor should be at least 300 mm, but it is better to do more, since the thermal insulation properties of the sawdust solution can vary greatly. On top of such a heater to cover the attic, walkways are laid for movement, which can be used as sheets of chipboard or thick plywood.

Advantages:

Comparative cheapness;
Environmental friendliness;
Good thermal insulation properties.

Flaws:

Labor-intensive self-production;
The thickness of the attic floor is large;
Complicated installation;
Differences in thermal insulation properties depending on the composition.

Insulation of the attic floor with expanded clay

Another relatively cheap material that can be used to insulate the attic floor in a private house is expanded clay. It is made by firing clay and is one of the most environmentally friendly building materials. In addition, expanded clay has good thermal insulation properties, is fireproof, durable and inert to acids and alkalis.

With the help of expanded clay, you can insulate both reinforced concrete and wooden floors of the attic. However, in the latter case, you need to carefully consider the calculation of the bearing capacity of the beams, since expanded clay thermal insulation weighs much more than modern heaters. Concrete attic floor slabs can easily withstand very heavy loads, so expanded clay can be used for them without additional calculations.

Good thermal insulation properties;

Fireproof;

Resistant to acids and alkalis;

Not subject to decay;

Durable;

Low cost.

Flaws:

Difficulty in installation.

Attic spaces, the frame of which is presented in the form of wooden trusses, are correctly referred to as "cold". These objects are not particularly resistant compared to reinforced concrete structures, but they have their own advantages.

Basically, they come down to the great possibilities of using heat-insulating materials. The classic attic floor on wooden beams is equipped with a heater with an ordinary carpentry tool, unlike reinforced concrete, where special equipment is needed.

Insulation of the attic floor, in addition to insulation, requires the installation of a competent vapor barrier and hood that prevent the formation of mold and fungus. And if you follow the technology correctly when installing the insulating material, then air exchange will be guaranteed.

The design of the attic directly depends on the parameters of the building and the purposes involving the use of this room. The under-roof space is assigned the role of a kind of air gap separating warm heated rooms from a cold roof.

At the same time, the floor in the attic room performs two tasks:

insulating. In the attic of the house, the air temperature is almost the same as the street indicators of degrees. In this case, the floors have an insulating function, thereby preventing the penetration of cold air into the living quarters.

Carrier. In most cases, the overlap along the wooden beams between the attic space and the upper floor of the house, as well as the walls, has a load-bearing function. In this regard, it must be reliable and durable, as people move along it, utensils are stored or any equipment is placed.

Therefore, in order to know the allowable load on attic floors, it is necessary to make a calculation. Then, based on their results, draw up a project from which it will be seen how to properly insulate the attic floor in the building.

The choice of material for insulation

The attic insulation technique is simple, since the material is laid directly on the floor, in the gap between the rafters and the wooden floor beams. If you plan to use the attic as an attic, then you need to insulate the roof.

To insulate the floor between the beams in the attic, several types of heaters are used:

Mineral wool.
Styrofoam.
Styrofoam.
Sawdust.
Expanded clay.
Foam.

Consider each warming product in more detail.

Mineral wool insulation

In order to save heat, the material must be placed between steam and waterproofing films. Vapor barrier protects against moist air masses that form in residential premises near the ceiling, especially at the junction with walls. The second layer protects the wool from water ingress from the roof through microcracks and holes in the roof.

They insulate the attic of the house most often from the side of the floor, rather than from the ceiling of the lower floor. For this, mineral wool is a reliable, low-cost insulating material with high compression, allowing you to cover the surface not only of the floor, but also of beams of various shapes. Such insulation is sold in rolls or plates of different thicknesses.

At the same time, it has the following advantages:

budget cost.
Ease of installation.
Rodents do not start in such a heater.
High fire safety material.
The ability to isolate any uneven surface.

At the same time, when working with mineral wool, it is necessary to take protective measures: wear tight clothing, work with glasses and protective gloves, and it is also advisable to use a respirator.

Styrofoam

Insulation of the attic space with foam plastic is a good option for converting it into an attic, suitable for year-round use. Such a material has a low thermal conductivity, as it is produced in the form of foamed air granules pressed into plates.

During installation, the foam must be cut in such a way that the plates fit snugly between the attic floors. Any gaps and cracks become "bridges" for the penetration of cold, and thereby significantly degrade the quality of insulation.

At the same time, it is necessary to observe the distance between the foam plastic plate and the waterproofing film of at least 2-3 cm. It is recommended to use it as a heater with a thickness of 70 mm, and in regions with a harsh climate - 100 mm.

Attention! When installing a vapor barrier film, you need to pay attention to the fact that it is facing the insulation with the right layer, according to the instructions. Otherwise, the opposite effect will be produced: all the steam will be directed towards the insulating material.

Extruded polystyrene foam

When insulating the ceiling of a residential building along attic floors, for many builders this material is considered the best option. This insulation does not cause difficulties during installation, it can be laid under any overlap of beams.

It also saves space, since you can get by with two to three times less thickness than when using the same mineral wool. Extruded polystyrene foam is different in appearance, since it is produced by different manufacturers. To insulate attic floors, the density of such a material should be about 32-34 kg / m, and its thickness should be from 40 to 100 mm.

And also manufacturers of polystyrene foam produce curly elements that lay out complex fragments in the attic floor. This insulation is convenient for installation in two layers: the first is laid between the attic floors, and the second layer is applied end-to-end along the bottom row, overlapping the wooden beams.

The main disadvantage of such a heater is that it is combustible. To reduce the fire hazard, you can lay mineral wool with expanded polystyrene, or add antipyrine.

Expanded clay

Expanded clay for the attic of a house is a traditional method of thermal insulation of a technical floor. This material is poured between wooden floors with a layer thickness of at least 150 mm. Such a mass is a universal tool that can isolate floor structures, and it can also be used as thermal insulation in conjunction with other bulk materials.

Attention! Expanded clay is a fairly light insulation, but when a thick layer is applied, the bearing surface of the floor will carry a large load.

Thermal insulation is best carried out at the construction stage of the building, since it is easy to waterproof the ceilings of the rooms under the attic and provide for an exhaust hood.

To do this, a vapor barrier film is covered on the ceiling to protect the expanded clay layer from getting wet. It is not recommended to pour it directly on the floor boards for another reason: during the operation and operation of the premises, a lot of dust is released, which penetrates into the living rooms.

Sawdust

Sawdust is a product of lumber processing in the woodworking industry. This is the cheapest insulation for attic floors, since you can buy sawdust at any sawmill for free. Thus, sawdust is now, as an option, a reliable heat insulator in attic spaces.

On a note! Sawdust are of organic origin, therefore, they are completely harmless to human health. Since ancient times in Russia, sawdust mixed with clay has been used as a heater in attics.

Sawdust has the following advantages:

Low cost insulation. Probably, the popularity of such a heater lies precisely because of this factor: its cost is almost equal to the consumption during transportation.
Safety for human health. Wood chips and sawdust do not cause skin irritation, allergies, poisoning, which cannot be said with full confidence about modern heaters.
Low thermal conductivity. Unlike wood, chips have a porous structure, so they have an underestimated heat conductivity.
Easy installation. To form a heat-insulating layer in the attic floors, no special skills are required. You just need to mix sawdust with clay or lime, and then pour it into the space between the attic floors.

The only significant drawback is the fire hazard of the material, despite the mixture with other non-combustible substances.

Foam

Recently, two types of insulating material have become popular for attic floor insulation: blown wool and ecowool. The latter material consists of 80% of cellulose fibers produced from waste paper, and 20% of additives, which are fire-fighting and antiseptic components.

Such a material has low thermal conductivity, it is very light, and looks like ordinary polyurethane foam. Both types of insulation are usually sprayed on boards between wooden beams, but sometimes ecowool is used in granules in a friable state. In this case, this mixture, as an option, is simply poured between the floor beams and compacted.

vapor barrier

The vapor barrier film protects the wooden floors of the beams from moisture formed in the air of residential premises. In addition, it protects the floors from the appearance of mold and fungus in the heat-insulating material.

Regardless of how the attic floor is made, the vapor barrier for the floor should form a continuous carpet that prevents the penetration of condensate. Particular attention should be paid to the joints with walls, where there is a high probability of condensate penetration. To do this, the covering film is overlapped and its edges are glued with adhesive tape.

Warming technology

For the correct application of insulation, follow the step-by-step instructions:

Step #1. Inspect and, if defects are found, correct them. Treat boards and timber with antiseptics and fungicides.

Step #2 Lay out the vapor barrier material, seal all gaps with mounting tape.

Step #3 Lay out (pour) insulation into the openings of wooden floors on the floor.

Step #4 Pay special attention to the joints between the plates of insulating material. Apply additional insulation if necessary.

Step #5 Lay the waterproofing film with an overlap, fasten the joints with mounting tape.

Step #6 Separately, install insulation on the ventilation duct, chimney pipes in the form of basalt wool, perlite, and it is advisable to install a special corrugation on top.

Installation of wooden beams of the attic floor

Attic ceilings are designed to separate living rooms from the under-roof space. They do not allow cold air to pass through, so their main task is their thermal insulation. And also various equipment is often installed in the attic.

In this regard, another important task is to create a solid foundation that can withstand this load. Thus, the safety of people, their comfortable living, as well as the durability of the structure depend on the quality arrangement of the wooden floor.

Attic flooring on wooden beams - standards, requirements

According to the requirements of SNiP 31-02, attic floors must withstand thermal, statistical, acoustic and fire conditions. In addition - to be energy-saving, therefore, reliable thermal insulation should be installed on the floors.

When installing an attic floor on wooden beams, all sanitary and hygienic requirements must be strictly maintained. When erecting a frame, it is necessary to build a structure, and then insulate the attic floor. At the same time, the same temperature should be maintained between the lower part of the attic and the living room. The difference in indicators in degrees according to the standards is allowed no more than 4˚С.

For the structural elements of the attic, a dry, seasoned beam with a section of 100 × 150 or 200 × 250 mm should be used, while the humidity in it is allowed no more than 20-30%. The distance between the supporting beams depends on the load, but usually it is taken at intervals of 3 to 6 meters. In addition to the bearing load, wooden floors need an ultimate margin of safety.

It must be borne in mind that the indicator of the smallest load on such load-bearing beams is 100 kg / sq. m. And the period of trouble-free operation of wooden floors according to the standards is 60 years. It is due to the fact that the wood is affected by fungus and insects, as well as a change in the strength of the beams under the influence of possible condensate.

For more information about the regulatory requirements for attic floors, see the video:

In particular, the joints between the rafters and the wall, as well as the supporting beams of the ceiling, should be protected with insulating material. Subject to all these conditions, the house will serve you faithfully for a long time.

Warming the attic floor of the house allows you to save more heat inside the room, and not spend it on heating a cold attic. Well, if it is used as a utility room (technical attic) or as an attic, but if not? Then it is pointless to spend resources on heating an unheated attic space.

That is why it is worth making the insulation of the cold attic ceiling using heat-insulating materials. You can perform insulation from the side of the attic or from the side of the room (inside / outside). It is best to do this during the construction period of the building, or immediately before the final finishing of the room. But even during the operation of the house, there is no reason not to insulate the ceiling from the attic.

The thickness of the attic floor insulation is standardized using SNiP II-3-79 "Construction Heat Engineering". This manual contains detailed recommendations on the choice and formulas for calculating the resistance to heat transfer of various thermal insulation materials. The calculations take into account not only the type of material, but also the average annual temperature, the duration of the heating season, the wall material of the house.

The attic floor insulation technology depends on the material chosen.

In this article we will consider the most popular heaters.

Mineral wool is a heater, the fibers of which are arranged in a certain way. Namely, this randomness leads to the fact that an air cushion is formed between the fibers, which informs the insulation of its properties. However, the same feature of cotton wool increases the ability to absorb moisture. To avoid this, you need to know how to properly install mineral wool.

Benefits of mineral wool:

high density;
long service life;
Fire safety;
ease of installation;
the use of mineral wool for insulation of horizontal surfaces does not lead to its caking, slipping and, as a result, the formation of cold bridges.

Among the disadvantages: the ability to absorb moisture.

There are three main ways to lay cotton wool: continuous, in grooves or in cells (see photo). The choice of method depends on what load will fall on the floor in the future. The most stable frame is obtained in the latter case.

First stage

It starts with laying the vapor barrier film. The film will allow you to remove the steam that rises from a warm living space to a cold attic. To lay the film correctly, you need to carefully read the markings applied to it. Be sure to observe an overlap of 100 mm.

Attic floor insulation technology with mineral wool Otherwise, the beams may rot.

At the junction of the film and walls or other protruding surfaces, it is necessary to raise it to a height equal to the thickness of the insulation plus 50 mm. and glue it with tape or wrap it on the insulation plate.

Second phase

Insulation (wool) is being laid. This is a fairly simple process. Slabs or strips are easily cut with a construction knife to the desired size.

When laying the sheet, make sure that there are no gaps left or that the mineral wool material is not strongly squeezed. Both will lead to a decrease in the quality of insulation. Typical mistakes in the photo.

a) insufficient thickness of the heat-insulating material;

b, c, d) the thickness of the attic floor insulation is incorrectly selected.

insulation with foil will increase the resistance of the material to heat loss. The sheet is laid with the foil side down.

the insulation should not protrude beyond the beam. If such a situation has arisen, the beam must be extended with a wooden beam or an additional rail to the thickness of the insulation.

a thin insulation laid in two layers retains more heat than one thick one. In this case, the plates must be laid in a checkerboard pattern.

if there are protruding structural elements in the attic, for example, a chimney pipe, you need to raise the insulation to a height of 400-500 mm. and fix it.

Third stage

Waterproofing is carried out if the attic is not supposed to be used, and the truss system is not protected by a waterproofing film. If the roofing material is separated from the attic with a film, then you can proceed with the final stage.

Draft floor. It is laid over the insulation and serves as the basis for the final finish.

The process according to the installation technology is similar to the insulation of the attic floor with polystyrene foam.

The advantages of these materials:

low cost;
ease of operation;
waterproof.

Among the disadvantages: flammability.

Attic floor insulation technology with polystyrene foam or polystyrene foam

The installation process of rigid insulation based on RїРµРЅРѕРїР»Р°СЃС‚Р° is more than simple and can be done by hand. The work can be divided into two stages:

surface leveling. To ensure high-quality insulation, there should be no significant irregularities on the floor of the base. You can eliminate such differences by performing a screed with a sand-cement mortar.

slabs are laid butt-to-butt or between beams. The presence of a bar increases the strength of the floor.

Insulation of the attic floor with foam plastic Draft coating

Styrofoam must be protected from destruction with a film in a non-residential attic. In a frequently used or residential attic, you need to somehow move, so it is better to equip an OSB subfloor or a sand-cement screed over polystyrene foam or polystyrene foam.

Sawdust is finely chopped wood.

Advantages:

naturalness;
no toxic impurities;
light weight;
material availability.

The disadvantage is flammability.

Attic insulation technology with sawdust

before proceeding with the insulation with sawdust, they need to be prepared. Namely, mix cement and water with sawdust in a ratio of 10:1:1.

Pour the attic floor with the finished mixture and level it. It is worth noting that it is possible to use sawdust as a heater without using a frame only in a non-residential attic. Otherwise, when walking on the floor, sawdust will be compressed, and the concrete screed will collapse.

build a cellular structure from a bar. Pour a solution with sawdust into each cell. The advantage of this method is that a subfloor can be laid along the timber. And the attic will be usable

Expanded clay is obtained by firing clay.

Advantages:

low thermal conductivity;
naturalness;
environmental friendliness;
ease;
availability.

The disadvantage is associated with the difficulty of lifting expanded clay to the height of the attic.

Expanded clay is usually used if it is necessary to insulate the attic floor over the slabs.

Expanded clay attic insulation technology

The work is carried out in three stages:

the plate is inspected for cracks and cracks. They are sealed with mortar or covered with thick paper. The protruding elements do not create difficulties with backfilling of expanded clay.

mount a crate from a bar. A rough floor will be laid on it in the future.

loose insulation is poured onto the stove and leveled with a conventional rake. Layer thickness 250-300 mm. You can move around expanded clay without restrictions.

Insulation of the attic floor with expanded clay Tip: when filling expanded clay, it is better to combine granules of different sizes (diameters). This way you can avoid the appearance of voids.

At the end, a subfloor is mounted or poured with a sand-cement screed.

Please note that the insulation of the attic wooden floor has some nuances:

the tree is subject to decay, which means that the steam rising up must pass freely. Improper installation of films or the use of non-breathable materials, such as roofing felt, will lead to the destruction of wood in the future.

using foil insulation, you need to place it with the foil down. So the wood will be protected from water ingress and at the same time, it will not accumulate steam moisture.

"Correct" - use a superdiffusion membrane or vapor barrier film

"Wrong" - to lay a special film without marking or even a regular film

The scheme of insulation of the attic floor for heaters of various types is given below.

Attic floor insulation scheme - 1

Attic floor insulation scheme - 2

moydomik.net

A bit from the history of roofing

Since ancient times, people have built private households with such high quality that they could stand for 100 years. At the same time, it was not cold to live in them, and the natural wood roof frame was always dry. As for the shape of the roofs on such buildings, they were most often built with two slopes, and had a slight slope.

This choice was explained by the fact that the snow that fell in winter had to linger on the roof and act as a natural insulation. In the attic of the building, one, less often two windows were made. They were closed for the winter and then the air in the under-roof space played the role of a heat insulator.

During the summer, the windows were opened slightly at night to cool the temperature in the attic. In the heat they were closed, and the air did not heat up. So in the attic they regulated the temperature.

In winter, when snow fell, it covered the roof with a continuous carpet and thus was a roofing natural heat insulator. Even in severe frosts, the temperature in the under-roof space did not drop below zero. As a result, the house was warm in cold weather.

At the same time, the roof slopes were not insulated so that the snow on them would not melt. The rafter system was left open, thereby allowing its inspection and maintenance. Therefore, in such attics, only floors were thermally insulated.

If the roof slopes are insulated, then the attic becomes a heated attic, which has a different functional purpose.

Building materials for floor insulation - the better to insulate

A large selection of building materials is presented on the domestic market. To decide how to insulate the ceiling of a cold attic, it is necessary to take into account the conditions in which the heat insulator will be operated.

There are a number of requirements for a heater:

preservation of its original qualities at temperatures from -30 to +30 degrees;
in hot weather, the material should not emit substances harmful to people and freeze in severe frost;
you need to choose a fire-resistant heat insulator if lighting is planned in the attic;
products must be moisture resistant so that when wet, their original properties do not decrease.

Before you purchase materials for insulating the floor of an unheated attic in a private household, you need to consider what the floor is made of. If these are wooden beams, then bulk, roll or slab heaters are used. When the ceiling was created from concrete slabs, bulk or slab insulators that are heavy in weight can be used. Often a cement screed is poured on the floor.

In the form of plates and mats they sell:

mineral wool;
extruded polystyrene foam;
Styrofoam;
straw;
seaweed.

In the form of rolls are made:

mineral wool;
stone and glass wool;
algae ladders.

One of the most popular options for arranging thermal insulation is the insulation of the attic floor with mineral wool.

Bulk materials include:

expanded clay;
sawdust;
straw;
reeds;
ecowool;
granular foam;
slag.

When laying insulation in the attic in a wooden house, you need to use natural, environmentally friendly and breathable materials.

Mineral wool attic insulation

This modern and popular insulation is produced in rolls or mats. Mineral wool does not burn, does not rot, various microorganisms and rodents are not dangerous to it.

Insulation of the attic floor with mineral wool is carried out in stages:

First lay the lining material on the floor. In the case of an economy option, inexpensive glassine is laid on the floor. A more expensive and high-quality device will be a flooring device made of a vapor barrier film, which is mounted with an overlap.
At the same time, the joints of the segments are glued with adhesive tape or fastened with wooden slats, fixing them with a stapler.
The width of the thermal insulation material is selected taking into account the technical standards for a particular region. The mineral wool between the lags is laid out tightly, leaving no gaps. Tape is used to seal the joints.
After the installation of the insulation is completed, even boards are placed on the logs and this is how the floor in the attic is formed.

The above solution on how to insulate the attic of a private house with mineral wool gives the material the ability to "breathe" and ventilate when moisture gets on it. To prevent the penetration of moist air into the insulation, waterproofing is mounted under the roof.

When working with mineral wool, you need to use protective equipment, such as a respirator, goggles, gloves and overalls.

Application of extruded polystyrene foam

Styrofoam (expanded polystyrene) refers to loose materials, so it is used if it is necessary to insulate a floor made of logs and beams. For thermal insulation of plates, extruded polystyrene foam is used, which is denser than conventional foam.

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

After it dries and becomes hard, the thermal insulation slabs are poured with a concrete mixture about 4–6 centimeters thick. After hardening, the screed becomes suitable for use as an attic floor. If desired, you can lay the final coating on the screed.

Insulation of a cold attic with ecowool

Ecowool is a lightweight and at the same time loose heat insulator, consisting of cellulose, it also contains flame retardants, such as boric acid and borax. Before starting work, a film is laid on the floor. For laying ecowool, a special blowing machine is used.

The heat-insulating layer is applied continuously, without leaving even the slightest gaps. Ecowool contains a large volume of air, so a layer of 250-300 millimeters is enough. When performing insulation, it should be remembered that shrinkage of this material occurs over time. Therefore, a layer of ecowool is applied with a margin of 40-50 millimeters.

Then the insulation must be moistened with water or with a solution. It is prepared from 200 grams of PVA glue and a bucket of water. The broom is moistened in the solution and the cotton wool is well moistened. After drying, lignin is formed on the heat-insulating layer - a crust that prevents the insulation from moving.

Which method of attic insulation from the above options to choose depends on the specific situation.

kryshadoma.com

And for those who like to delve into absolutely all the subtleties of construction - a useful video:

What insulation is suitable for the attic?

It is necessary to insulate the attic floor when the attic space is not planned to be used for housing. Those. we are talking about a cold attic, the roof slopes of which are not insulated at all. And far from all the same materials are already suitable for overlapping, they are selected for slopes.

Mineral wool: no harmful dust

So, when insulating the attic floor with mineral wool, it is correct to use the so-called tension method. Its essence is that first the insulating material is laid - and so that it registers between the beams.

After that, a slab or rolled mineral wool insulation with a total thickness of about 150 millimeters is laid on it in three layers, and it is covered with a vapor barrier film on top. After that, plywood, which should be no thinner than 18 millimeters.

Expanded polystyrene and foam: ease of installation

High-quality insulation of the attic floor with expanded polystyrene is also obtained, the main advantage of which is that there is no need for vapor barrier, and all gaps are easily sealed with mounting foam.

Inflatable insulation: fashion and rationality

Recently, it has become especially popular to insulate the attic floor by blowing.

The main advantage of blown insulation is that it fills all the voids that exist by itself and creates an even continuous layer. In which there are no joints, no seams and no adjoining, and for which there is no need to cut separate small pieces of prickly insulation to plug something.

Today, for the insulation of cold attics in Russia, two types of blown insulation are mainly used: ecowool and blown wool.

Ecowool up to 80% consists of cellulose fibers, which are produced from ordinary waste paper, and 20% from additives such as snowstorm as a fire retardant and boric acid as an antiseptic. Such a heater has a high thermal conductivity.

But blown wool is obtained by grinding ordinary mineral materials for thermal insulation, which for some reason did not pass the product acceptance.

For example, they did not have sufficient density or the correct structure of the fibers. And such material is crushed and packed under high pressure, and therefore it is easy to transport it to the site of the facility, where everything will be loosened again upon arrival.

But still, ecowool is most often used as a material. The insulation itself in the process looks like this: one person must remain near the installation and monitor its normal operation, while loading the material. And the second person goes up to the attic with the hose, makes a cruciform incision on the vapor barrier (just between the beams), inserts the hose into this incision, and fills the cavity with material.

Plus, relatively inexpensive bulk materials are used to insulate a cold attic:

What parameters of the heater should be paid attention to?

In no case do we urge you to purchase the most expensive heat-insulating materials to insulate your attic floor. But note that the more and longer any well-known company produces materials for this purpose, the more it pays attention to quality, changing their bulk density, improving their products and increasing thermal insulation coefficients. And that already says something.

For the rest, always pay attention to such parameters of heaters that are important for a wooden floor, and have none for concrete - and vice versa.

Parameter number 1. Biostability

We are talking about the fact that in such a heater, which often remains open, bugs or some other living creatures do not start. This is especially true of mice, who love to live in a warm and dry (and, most importantly, deserted) attic.

Another important requirement for attic insulation is water resistance. Raindrops accidentally falling into it or simply moisture should not lead to the process of decay.

Glass wool is recognized as one of the most resistant heaters:

Parameter number 2. Thermal conductivity

The main requirements for insulation for the attic floor is the ability to maintain thermal insulation properties for a long time.

When buying a heater, also pay attention to such an interesting point: modern manufacturers of thermal insulation materials always indicate in the technical specification three coefficients of thermal conductivity of the material at once: in a dry state, at a temperature of 10 ° and 25 °, and humidity categories A and B.

You need to look at the coefficient of thermal conductivity in a dry state, or at a temperature of 10 degrees, because this is exactly the normal climatic situation in the attic. For a more accurate and detailed thermal calculation, you will need a SNiP table.

Now let's take a moment. When choosing a heater, you will probably be advised to take a heater with the lowest possible degree of thermal conductivity. But in fact, this only makes sense for residential attics, because when you have to insulate the roof slopes, then too thick materials cannot be laid between the rafters. Therefore, materials are needed here that will conduct heat as poorly as possible, but at the same time have a small thickness.

But for the attic floor, just the thickness of the insulation is not a critical factor, and you can save on this. Just take a cheaper insulation, but thicker, albeit with high thermal conductivity. You are all compensated by the height of the insulation itself.

Parameter number 3. Weight

Depending on the chemical composition, each insulation has its own volumetric mass. So, materials such as basalt, glass and any other inorganic and organic compounds are most often used as the basis for fibers. From their type, the heat-insulating material itself becomes either light or heavy. And the shape of all these materials is provided precisely by the elasticity of the fibers: how much they straighten between the floor beams.

Note that heavy insulation keeps its shape better due to the rigidity of its fibers. And foam insulation has the best stability for attic floor insulation, which in this parameter is equated to hard stone wool. But there is a moment: the same mineral wool insulation that was inserted between the floor beams can be easily straightened and pressed tightly against the wood, but the foam will not do this, and voids form - the bridges are cold. Therefore, you will have to additionally use a can of foam to close all the cracks.

On the other hand, if the attic floor is insulated on a reinforced concrete slab with foam-based materials, then there will only be pluses. Not to mention the fact that the attic concrete floor itself already has a considerable weight and creates a serious load on the walls and foundation of the house, and the use of light insulation for it is only a big bonus.

And unlike the concrete floor, the attic floor is able to withstand a fairly limited load. Therefore, the weight of the insulation in this regard is also not the last moment. After all, there are already many variations here: the same cubic meter of thermal insulation can weigh as much as 11 kilograms, and all 350 - this is the norm.

One of the heaviest heaters is basalt wool:

Parameter number 4. Moisture resistance

Rain moisture or roof leaks accidentally getting into the insulation should not start the rotting process. It is bad if after six months or a year the new insulation begins to decompose from the inside, while emitting an unpleasant smell of dampness.

Therefore, attic floor insulation on wooden beams and on concrete is quite often done using polystyrene foam or polystyrene foam, which are known for their almost zero hydrophobicity.

Parameter number 5. Environmental friendliness

Another point: the attic insulation should not emit any toxic and pungent substances in terms of smell, despite the fact that, perhaps, no one will walk in such an attic.

It's all about ventilation: sooner or later, the insulation molecules are picked up by the air and brought into the living quarters, which can be unsafe for the residents of the house. Therefore, choose a heater that meets sanitary standards.

Parameter number 6. Shape saving

Another important point is the form stability of the selected insulation. So, special laboratory tests have shown that over time, heat loss through the gaps between the plates or the matte heat insulator can reach 40%. And this despite the fact that the material itself during the same time may not change its thermal conductivity at all, if at the same time it remained dry.

Therefore, the stability of the shape and dimensions of the material over time is very important. For the concrete floor of the attic, such gaps will not be critical, because here the floor itself is quite heat-insulating, which cannot be said about the attic floor.

But the problem is that in the technical information for modern heat insulators such a parameter as shape or stability cannot be found.

Parameter number 7. Fire safety

And the last point: attic insulation must meet all fire safety requirements. Take the same popular ecowool, which is not just made from ordinary waste paper and pieces of newspapers. It would seem that everything is simple and ingenious, why don't you cut the paper into smaller pieces too, and just fill the attic with it? Would it be worse? After all, the principle of friability is also involved here, like in animal hair, when air molecules get stuck between small elements.

Let's just say: yes, the insulating properties of this method will not be worse, but it is the old dry paper and wood that most often leads to an unexpected fire. That is why modern cellulose insulation is necessarily treated with special chemicals against fire.

If we are talking about the combustibility of materials, then it is important that the insulation not only does not burn, but also has attenuation. Just remember that everything burns at the epicenter of the fire, both iron and concrete, but if a spark falls on the attic floor, then the insulation should not light up. That's what it's all about.

This is what the attic insulation cake itself should look like:

Vapor barrier questions: how, on which side and is it necessary?

For the insulation of roofing made of wood and concrete, the vapor permeability of the insulation is of great importance. So, all heaters that are made today in the form of plates and rolls can be conditionally divided into "wool" and "foam", as building contractors like to do.

To "cotton" we will refer heat-insulating materials from organic and mineral fibers - these are mineral wool, stone wool and glass wool insulation. All these materials are formed by the hardening of plastic masses of very different chemical origins. And all these materials have approximately the same coefficient of thermal conductivity: within 0.04.

All these materials are made up of fibers that are intertwined with each other. They do not form any closed pores, and water vapor easily enters and escapes through them. Therefore, all wadded heaters are vapor-permeable materials. Why, under production conditions, their fibers are additionally coated with a special water-repellent substance, and the heaters also turn out to be hydrophobized: a water molecule from water vapor is not allowed to penetrate and wet the insulation. It can only cling to its surface, and when a critical mass accumulates, it transforms into drops and rolls down. It turns out that hydrophobized cotton wool insulation is not a wet vapor-permeable material.

Therefore, until now, scientists from all over the world cannot come to an unambiguous conclusion: the vapor permeability of building insulation is good or bad. Let's just say that if you equip the attic floor on wooden beams, you'd better lay vapor-permeable materials on it so that the wooden rafters, which have taken on moisture from the lower living quarters (and water vapor always rises), can freely give it to the insulation . And they will easily come out of the insulation - through ventilation alone is enough. But in terms of floor insulation on concrete, there is not much difference. But there is such a moment here: when using vapor-permeable heaters, it is important that the ventilation of such an attic is organized in accordance with all the rules, and a separate ventilation system will not interfere.

Note that there are no fibers in foam insulation, since such material is literally made from air. All foam insulation consists of a cellular structure, with closed bubbles and not closed, like a kitchen sponge. Therefore, such heat insulators can be both vapor-permeable and non-vapor-permeable. For example, extruded polystyrene foam, which is better known to us as polystyrene, passes water vapor between the balls, but extruded polystyrene foam does not.

Interestingly, you can use not only one type of insulation, but two at once to compensate for each other's shortcomings. But at the same time, a heat-insulating material with a lower vapor permeability must necessarily lie in front of a heater with a high vapor permeability. That is, first polystyrene foam, then cotton wool. Otherwise, in the opposite case, a material with a lower vapor permeability will become a certain vapor barrier for another material, it will simply begin to rot and there will be nowhere for moisture to go.

How to insulate a concrete attic floor

If we are talking about the insulation of the attic floor of concrete, then the thermal insulation must necessarily be in the form of two or three layers with overlapping joints of each lower layer. Moreover, it is very important that the entire surface be leveled so that there are no irregularities of more than 5 millimeters anywhere - this is not difficult to achieve with modern leveling compounds.

For concrete attic floors, extruded polystyrene foam slabs are ideal as thermal insulation. They don't need a vapor barrier, but if you put styrofoam - it's not extruded polystyrene foam, and then, of course, you need it.

Additionally, if you later need to walk on such a floor, you can make a cement-sand screed up to 4 centimeters and put two layers of drywall sheets. Just be sure to make masonry mesh paths for such a screed that you will walk along. Be sure to glue the joints between the foam polystyrene plates with tape so that cement milk does not leak between the plates.

The attic floor itself can be insulated both at the manufacturing stage and at almost any time during the operation of the house itself. Of course, for the attic it is much more correct to insulate the floor even before you move into your new home.

More details about the process itself:

How to insulate a wooden attic floor

So, there are two main ways to insulate the attic floor: laying a heat-insulating layer inside the structure of the attic floor, and laying insulation on top of it. For a cold and non-residential attic, it is not necessary to cover the insulation with something on top and build a full-fledged floor. But then be sure to leave the running ladders - separate paths from the sparse flooring throughout the attic area, this is necessary for roof maintenance.

Under the insulation, you need to put a vapor barrier, and in the form of a trough, so that it can protect the insulation from water vapor, which comes from the lower living quarters. But there is an exception to this rule: if the insulation was laid with good resistance, for example, it is foam or extruded polystyrene foam, then vapor barrier is not needed here. But if we are talking about an attic with a particularly wet regime, for example, above a kitchen or a sauna, then a vapor barrier layer must be installed here.

Another method is tension, when the vapor barrier only sags slightly between the beams. The disadvantage of this method is that in this way the insulation between the beams is not inserted tightly enough.

And if the overlap is also made from ready-made companies, then this option is not suitable at all, because such voids quickly become the so-called cold bridges. Therefore, in Russia the method is more popular, in which the insulation is first laid, then it is covered with a vapor barrier, and only then - with a finishing floor.

So, this is what the whole process of warming looks like:

Step 1. A vapor barrier is fixed between the beams using a construction stapler.
Step 2. Next, mineral wool slabs are cut so that their width is corresponding to the step of the beams.
Step 3. These plates are carefully inserted into the gap between the beams.
Step 4. For a while, while the ceiling is not yet ready below, so that the insulation does not fall between the beams, it is supported by draft bars or a strong thread stretched especially for this.
Step 5. Next, a diffuse membrane is quickly mounted on top of the insulation - so that steam can easily escape through it, and drops from above from the slopes do not penetrate inside.

But let us also note such a moment about the last step. Many experts believe that no diffuse membranes or windproof films are needed for insulation, because in a cold attic, thermal insulation will dry due to natural ventilation of convection air flows that easily penetrate through holes and dormer windows.

If you are finishing building a house, almost finishing work has already been done and you don’t know whether to take on the attic or whether this business can wait, and in general what is needed at this stage, this article will help you. Here we look at attic insulation with different types of materials, with step-by-step illustrations, expert advice and a helpful video.

We will also reveal many important points why insulation is so necessary and what the attic floor pie should actually be like on wooden beams and on a reinforced concrete slab - step by step.

What insulation is suitable for the attic?

Mineral wool: no harmful dust

Expanded polystyrene and foam: ease of installation

Inflatable insulation: fashion and rationality

Recently, it has become especially popular to insulate the attic floor by blowing.

Today, for the insulation of cold attics in Russia, two types of blown insulation are mainly used: ecowool and blown wool.

But blown wool is obtained by grinding ordinary mineral materials for thermal insulation, which for some reason did not pass the product acceptance.

Plus, relatively inexpensive bulk materials are used to insulate a cold attic:

What parameters of the heater should be paid attention to?

For the rest, always pay attention to such parameters of heaters that are important for a wooden floor, and have none for concrete - and vice versa.

Parameter number 1. Biostability

Another important requirement for attic insulation is water resistance. Raindrops accidentally falling into it or simply moisture should not lead to the process of decay.

Glass wool is recognized as one of the most resistant heaters:

Parameter number 2. Thermal conductivity

The main requirements for insulation for the attic floor is the ability to maintain thermal insulation properties for a long time.

Parameter number 3. Weight

One of the heaviest heaters is basalt wool:

Parameter number 4. Moisture resistance

Therefore, attic floor insulation on wooden beams and on concrete is quite often done using polystyrene foam or polystyrene foam, which are known for their almost zero hydrophobicity.

Parameter number 5. Environmental friendliness

Another point: the attic insulation should not emit any toxic and pungent substances in terms of smell, despite the fact that, perhaps, no one will walk in such an attic.

Parameter number 6. Shape saving

But the problem is that in the technical information for modern heat insulators such a parameter as shape or stability cannot be found.

Parameter number 7. Fire safety

This is what the attic insulation cake itself should look like:

Vapor barrier questions: how, on which side and is it necessary?

How to insulate a concrete attic floor

More details about the process itself:

How to insulate a wooden attic floor

So, this is what the whole process of warming looks like:

Step 1. A vapor barrier is fixed between the beams using a construction stapler.
Step 2. Next, mineral wool slabs are cut so that their width is corresponding to the step of the beams.
Step 3. These plates are carefully inserted into the gap between the beams.
Step 4. For a while, while the ceiling is not yet ready below, so that the insulation does not fall between the beams, it is supported by draft bars or a strong thread stretched especially for this.
Step 5. Next, a diffuse membrane is quickly mounted on top of the insulation - so that steam can easily escape through it, and drops from above from the slopes do not penetrate inside.

How to leave running ladders in a heater

If you use soft thermal insulation materials to insulate the attic floor, you need to make running ladders above them - but only so that cold bridges do not turn out. Therefore, it is better to take either rigid materials, or insert the legs of the ladders directly into the insulation.