How to insulate an attic with wooden beams. Cold attic floor insulation

The attic floor separates the heated part of the building from the cold part. Choose right necessary material and the thickness of the insulator - this means to reduce heat loss and save material costs in heating season. Let's talk about insulation attic floor By wooden beams with your own hands.

Construction of a wooden attic floor

The load-bearing elements in the attic wooden floor are beams. They are made from coniferous wood. The size of the section of the beams is taken according to the calculation for the load that the element perceives. We told you about the correct calculation of wooden floor beams in the article "How to calculate wooden floor beams".

For each specific climatic conditions and depending on the ability of the material to resist heat transfer along thermotechnical calculation it turns out its own value of the thickness of the heat insulator.

Scheme of insulation of the attic floor: 1 - log; 2 - cranial bars; 3 - board shield or boards; 4 - vapor barrier; 5 - counter-lattice for the ventilation gap; 6 - insulation; 7 - clean floor; 8 - ventilation gap

The black floor of wooden shields or boards is mounted on cranial bars. Next, a membrane-type vapor barrier is laid, a heater is laid on it, which is covered with another layer of the membrane.

If the attic is in use, a clean floor is laid on top. If not, then running boards (min. 40 mm thick) are laid on the beams. All wooden elements are antiseptic. To ventilate wooden structures, when laying a clean floor, a gap is left between it and the insulation.

The choice of material for insulation

Bulk materials

Expanded clay

It is possible to insulate attic floors with bulk materials, which include expanded clay. It has a relatively low weight (250-600 kg / m 3) and high resistance to heat transfer. Ease of installation and relative cheapness determine the choice of this material.

Vermiculite

Expanded vermiculite is obtained by heating the vermiculite rock to a temperature of 700 ° C, which at the same time increases in volume by 25 times. Its thermal conductivity is from 0.13 W / m K, and the volumetric weight is up to 200 kg / m 3.

Perlite

Expanded perlite also belongs to loose heat-insulating materials. The perlite rock is crushed and fired to obtain a porous structure. Expanded perlite is environmentally friendly, non-flammable and bioresistant, has high thermal insulation properties (0.052 W/m·K). Its volumetric weight is 160-250 kg/m 3 .

piece materials

Piece insulating materials are produced in the form of: sheets, rolls, plates, mounting shells and segments. To insulate the attic floor, slabs and rolls are most often used. At the same time, a roll-type insulation is preferable, since it does not leave butt joints, which slightly worsen the resistance to heat transfer.

Basalt wool

Mineral wool slabs and rolls of basalt fibers are the most popular heat-insulating material in housing construction. It is made from crushed and melted basalt by blowing. Basalt wool has a low thermal conductivity (0.32-0.048 W / m K), low volumetric weight. This material is bioresistant, environmentally friendly and relatively inexpensive.

glass wool

Glass wool in its characteristics is very close to mineral wool. It is also obtained by melting the source material, which in this case is cullet. Glass wool has longer threads, greater chemical resistance and strength, lower cost than mineral wool.

It is produced in the form of plates, mats, rolls, reinforced and with a reflective layer. The volumetric weight of glass wool is from 25 to 200 kg / m 3, heat absorption - 0.035-0.045 W / m K. The disadvantage of fiberglass is the need personal protection during installation.

Styrofoam

Expanded polystyrene (foam plastic) also belongs to plate heaters. This is a cheap, lightweight, moisture-resistant material with good thermal insulation properties. In private housing construction, it is often abandoned due to rodent damage and low resistance to high temperatures.

Extruded polystyrene foam (penoplex) has good properties insulation, less flammable than simple polystyrene foam, but when burned, it releases toxic substances.

polyurethane foam

Plate polyurethane foam (foam rubber) has a high resistance to heat transfer (0.029-0.041 W / m K) and low volumetric weight (30-80 kg / m 3). Rigid types of this material are used in construction. The sprayed polyurethane foam creates a continuous insulation of the surface, both thermally and hydro. It is also resistant to temperature extremes and durable in operation (up to 20 years).

Foam glass

Foam glass is a type of glass that has a cellular structure. It has low thermal conductivity (0.04-0.08 W / m K), water resistance, high strength and fire safety. The percentage of porosity of foam glass reaches 80-95%. The volumetric weight varies from 100-200 kg/m 3 .

Peat slabs

Peat slabs belong to organic heat-insulating materials. They are made from young sphagnum moss using a wet and dry method. Under the influence of temperature, the peat fibers stick together. Peat slabs are divided into ordinary and moisture resistant. Their volumetric weight is 170-300 kg / m 3, the thermal conductivity coefficient is 0.05-0.07 W / m K.

Fiberboard

Fibrolite boards are made from wood fiber, which is first mineralized and then mixed in the required proportion (cement - water). Heat-insulating boards have a lower volumetric weight (300-350 kg/m 3) and thermal conductivity (0.085-0.95 W/m K) than a structural fiberboard.

It is quite affordable to make a fibrolite mixture yourself and lay it directly in place. It is possible to pre-make slabs from it using a special technology in the formwork right size and then mount them on the floor.

reeds

As a heat-insulating material, reeds are also used, which is practically the cheapest. It is made from pressed reed stalks sewn with steel wire.

The volumetric weight of reed is 175-250 kg / m 3, the heat absorption coefficient is 0.05-0.08 W / m K. Its disadvantages are low fire resistance and biostability, high water absorption and damage by rodents.

Ecowool

Ecowool (cellulose wool) refers to environmentally friendly heat-insulating materials. It is made from recycled cellulose raw materials with the addition of antiseptics and fire retardants. Most often they are boric acid and borax.

In stores, it can be found packed in plastic bags. When laying, ecowool is loosened and then laid out at the place of insulation. In fact, the density of the insulation should be at least 35 kg / m 3 for overlapping, which is quite difficult to determine “by eye”.

This heat-insulating material has good thermal conductivity - 0.037-0.042 W / m K, low volumetric weight (28-63 kg / m 3), moderately combustible and bio-resistant. Ecowool can prevent about 20% of humidity from passing into the inner layers, while maintaining its thermal insulation properties.

Cork slabs for thermal insulation have been used for a long time. They are made from shredded cork waste by mixing with glue or heat treatment. Pressed plates in special forms are dried at a temperature of 80 °C.

The volumetric weight of cork insulation is small and amounts to 150-250 kg / m 3, the thermal insulation index is high (0.04-0.08 W / m K). The advantages of this insulator include:

biostability;
low water absorption;
low volumetric weight;
relatively high strength as a heat-insulating material;
fire resistance (smolders slowly);
not attacked by rodents.

Features of laying thermal insulation on a wooden floor

Insulation made of mineral and glass wool is laid with mandatory vapor barrier. Absorbing water, the insulation loses its thermal properties, so careful protection against moisture is needed. The vapor barrier films are laid with an overlap of 100 mm.

A heat insulator with a reflective coating reduces the heat loss of the ceiling. It is laid down with foil. The use of penofol is justified only in baths and saunas.

If the thickness of the heat-insulating material is greater than the height of the floor beams, it is necessary to lay additional rails to create an air gap. Multilayer thermal insulation is arranged with overlapping butt joints.

Rigid dimensions thermal insulation boards adjusted with special care so that the gaps do not increase the thermal conductivity of the floor. Otherwise, the installation of this type of insulation does not differ from the installation of thermal insulation from mineral wool boards.

Bulk heat insulators are evenly distributed over the entire space between the beams, observing the required (calculated) layer thickness. Since almost all of them absorb moisture, such an insulator is protected from moisture by a membrane film from above and below.

The choice of material for thermal insulation of the attic floor is determined by the following criteria:

Material costs, including shipping costs.
Local availability of material.
Ease of installation.
Health safety.
Fire safety.

It is possible to reduce the stress of the building structure by choosing a heater with a lower volumetric weight and a low heat absorption index.

Insulation of the attic floor makes it possible to save thermal energy inside the room, thereby preventing the cost of heating a cold attic. Still nothing if the attic is used as a utility room or attic, but what if not? Of course, it makes no sense to spend money on heating it in this case.

For this reason, it is desirable to cover the attic floor with the use of thermal insulation materials. This can be done both outside and inside. Ideally, insulation should begin at the stage of building a house or, alternatively, right before finishing the premises. However, even while living there is no reason not to take care of the insulation of the ceiling from the attic.

Note! The thickness of the insulation layer is stated in SNiP. In addition, there you can find all the necessary calculations of the heat transfer resistance of various insulating materials taking into account the average annual temperature, the material used in construction and the length of the heating season.

But before proceeding directly to the insulation, you must identify the type of attic floor. In the private construction of residential buildings (regardless of whether wood is used, bricks or blocks), it can only be of two types. But both must be built according to certain rules and have a well-defined design.

Basic requirements for attic floors

The main quality that without fail any attic floor should have, this is strength. If it's about mansard roof, then the entire structure should not sag or deform under the weight of furniture or equipment located in the attic. There is such a thing as the norm of deflection. For attic structures, it is 1/200 of the entire span. The maximum load per square meter is 105 kilograms. Another equally important parameter of the floor is fire safety, which is more true for wood structures. So, fire resistance has such limits:

for concrete or reinforced concrete structures it is 1 hour;
for wooden structures (in the absence of additional protection) - five minutes;
for wooden floors along beams, with backfill and plaster - about 45 minutes;
for wooden floors with only one plastered surface - 15 minutes.

Features of the overlap device

It is often the beam ceiling that is encountered, which is explained by the simplicity and low cost of installation, so we will focus on it. Often they are found in wooden buildings, and elements of both wood and metal can serve as beams. According to experts, option number 1 is preferable, because:

wood is cheaper than metal;
it has excellent thermal insulation performance;
it is easier to handle.

Insulation of the attic floor, if there are beams, consists in laying insulating material between them. If the height of the beams is not enough for this, then the bars are additionally stuffed from above. Before proceeding with laying, a vapor barrier layer should be laid (only not a plastic film, since the vapors that leave the room will not be able to penetrate outside). And if the film is still used, then the level of humidity in the house will increase markedly, especially if ventilation system works poorly. For this reason, it is preferable to purchase a modern vapor barrier, which can be laid in such a way that the air leaves the room, but does not penetrate into the house from the attic. And if such material is with foil, then it must be laid “face down”.

But how to choose the right insulation so that the resulting “sandwich” is as effective as possible? We will talk about this now.

Types of insulation for the attic

There are a lot of such materials, but we will consider only the most popular of them. Here they are:

mineral wool;
Styrofoam;
sawdust;
expanded clay.

Let's take a closer look at each of the options.

The use of mineral wool

Mineral wool is an effective insulation, the fibers in which are located in a special way. Due to such randomness, an oxygen “cushion” is formed between the fibers, due to which the material acquires its properties. But because of the same feature, mineral wool or absorbs moisture. In order to prevent this, the installation must be carried out properly.

The advantages of this material are undeniable:

density;
ease of installation;
long service life;
fire safety;
finally, if the cotton wool is installed horizontally, then it does not slip and does not cake (read: cold bridges do not appear).

But there is also a drawback that we talked about - it absorbs moisture.

Mounting technology

Mineral wool can be laid in three possible ways:

into cells;
into furrows;
continuous.

The first method is the most efficient. The laying technology itself is as follows.

Step 1. First, lay the vapor barrier material - this is necessary to remove the steam that rises from the premises. For proper installation, you must familiarize yourself with the markings on the film made by the manufacturer.

Note! Do not forget to observe the obligatory overlap of 10 centimeters.

If thermal insulation is made along the beams, then the vapor barrier must go around each element that protrudes, otherwise the beams will soon rot.

Step 2 Where the film joins with walls and other surfaces that protrude, lift it to the height of the insulating material + 5 centimeters, then wrap it behind the material plates or glue it with adhesive tape.

Step 3 After that, proceed to laying the insulating material. This procedure is extremely simple, since strips and slabs can be easily cut with a construction knife.

Step 4 When laying, pay attention to the fact that the insulation is not squeezed and there are no gaps. You can see common mistakes in the image below.

/p>

In the first case, the thickness of the thermal insulation is not enough; in the rest, the same parameter of the attic floor is incorrectly selected.

Foil material will increase resistance to heat loss. But the material itself should be laid down with foil.
If there are protruding structural elements in the attic, then the insulation should be raised by 40-50 centimeters and fixed.
If a thin insulation material is laid in two layers, then it will be more effective than one thick layer.
Do not allow material to protrude beyond the beams. But if this still happened, extend it with a rail or beam to the thickness of the material itself.

Step 5 If rafter system is not protected by a waterproofing layer, and the attic space will not be used, it is necessary to lay waterproofing.

Step 6 It remains only to make a rough floor. To do this, lay it on a heater - this will be the basis for the final finish.

Use of Styrofoam

Insulation of the attic floor with polystyrene foam is in many ways reminiscent of a similar procedure with the use of polystyrene foam. Moreover, the advantages of these materials are common - here they are:

cheapness;
water resistance;
ease of installation.

Mounting technology

Installing foam for attic insulation is extremely simple - you can easily handle the procedure on your own. All work is divided into several stages.

Step 1. Level the surface. In order for the thermal insulation to be of the highest quality, no irregularities should remain on the base. And if you need to eliminate the recesses, then fill everything with a cement screed.

Step 2 Lay the insulation boards - between the bars or end-to-end. What is characteristic, if there are bars, then the strength of the structure will increase significantly.

Note! All joints (between the bars inclusive) must be carefully sealed. When avoiding obstacles, cut holes as accurately as possible. Finally, it is best to save thermal energy just a uniform layer.

To protect the foam in a non-residential attic from destruction, you can use a film. But if the attic is used frequently and people move along it, then the foam must be covered with a subfloor - it can be like a cement and sand screed or OSB boards.

Using sawdust for attic insulation

Who does not know, shredded wood is called sawdust. We are talking about this material now, because it also has significant advantages, including:

availability;
naturalness;
light weight;
absence of any harmful or toxic substances.

The minus is the same as that of polystyrene - flammability.

The procedure for warming with sawdust

Step 1. First, prepare the sawdust, that is, mix it with water and cement in a ratio of 10-1-1.

Step 2 Pour the attic floor with the resulting mixture, and then carefully level it. Note that it is possible to insulate the attic with sawdust without a frame only if it (the attic) is non-residential. Otherwise, the sawdust will be pressed while walking, and the screed, respectively, will collapse.

Step 3 Using timber, build a honeycomb structure. Next, fill each cell with the mixture described above. The main advantage of this technology is that it will be possible to lay a subfloor on top of the timber, and the room itself can be actively used.

The use of expanded clay for insulation

Sufficiently high-quality insulation of the attic floor can be made using expanded clay. Who does not know, this material is obtained after firing clay. The main advantages of expanded clay include:

availability;
low thermal conductivity;
light weight;
environmental friendliness;
naturalness.

But there is also a minus, which lies in the difficulty of raising the material to the height of the attic.

Note! Often this material is used when it is required to insulate the ceiling over the slabs.

Instructions for insulation with expanded clay

The whole procedure can be conditionally divided into the following stages.

Step 1. First, inspect the plates for cracks or gaps. If any are found, seal them with mortar and cover with thick paper. What is characteristic, even with protruding structural elements, there are no difficulties when backfilling.

Step 2 Using a beam, build a crate. A subfloor will subsequently be laid on top of this grating.

Step 3 Pour the material onto the slab and level it with a rake. The thickness should be approximately 25-30 centimeters. It is characteristic that you can walk on expanded clay - there are no restrictions in this case.

Note! Falling asleep expanded clay, try to combine pebbles of various fractions (sizes). This will prevent voids from forming.

At the end, fill everything with a concrete screed or mount a subfloor.

The main nuances of the procedure

The tree rots, therefore, the steam rising from the house must pass freely. If you install a vapor barrier or use a material that does not "breathe" for this, then soon the tree may collapse.
Insulation with foil should be laid with it (foil) down to protect the wood from moisture.

You can see examples of correct and incorrect installation in the image below.

But the universal scheme is the insulation of the attic floor using any of the materials.

Video - thermal insulation of the attic floor

As a result, we note that the thermal insulation of the attic floor will be as effective as possible if the attic itself is reliably protected from the penetration of moisture from the outside. In other words, you also need to properly equip the roof. Good luck with your work!

During the heating period, up to 15-20% of heat can escape through the "cold" roof. That is why the issue of attic floor insulation along wooden beams is relevant for many homeowners. Specialists offer several options for thermal insulation, each of which has its pros and cons.

In private houses, the attic floor is most often made of wood. This allows optimize construction costs, reduce the overall load on the foundation . In addition, working with wood does not require the involvement of special equipment.

Proper organization of thermal insulation of the beam structure of the ceiling allows not only to reduce the cost of heating the house, but also:

improve the microclimate in the house in the summer - avoid excessive heating and additional costs for air conditioning;
minimize the amount of moisture, condensate - this helps to extend the life of the attic structure: the tree will not rot, but metal elements- subject to corrosion;
reduce the formation of ice and icicles on the roof by lowering the temperature of roofing materials.

That is why it is so important to ensure complete reliable insulation of the attic space.

What materials can be used

High-quality insulation for floors made of wooden beams should be different:

light weight so as not to create an extra load;
low thermal conductivity, in which case a smaller layer is required;
moisture resistance- moisture that accidentally gets into the insulation can become an environment for the active reproduction of fungi, mold;
fire safety;
geometry resistance- otherwise, over time, the insulation material will lose its characteristics and begin to collapse;
biological stability– the material should not be a habitat for microbes and bacilli.

For effective insulation of the attic floor on wooden beams, the following are used: solid ( slab), rolled, bulk or liquid ( sprayed) materials.

Piece insulation

Mineral and basalt wool consists of many microfibers connected in a chaotic manner. different enough low thermal conductivity, fire safety and light weight. Over time, mineral wool practically does not deform. Suitable for thermal insulation of attic floors roll and plate insulation. The disadvantages of cotton wool include it ability to absorb moisture with a subsequent decrease in their thermal performance and the need to fit in special means personal protection(mittens, respirator, etc.).

Styrofoam combines several positive parameters: low cost, lightness and good heat-insulating ability. He moisture resistant and easy to install. Cutting with a sheet can be carried out with an ordinary clerical knife. However, many homeowners are refusing to use Styrofoam due to its low resistance to elevated temperatures and a high probability of damage to the material by rodents.

Extruded polystyrene foam has a denser structure. It is characterized zero capillarity, good resistance to seasonal temperature fluctuations. For ease of installation, sheets with a groove-comb system are used.

Cork slabs provide good heat and sound insulation. They are not affected by rodents, slowly smolder when ignited, have increased strength. The thermal insulation index of the plates is 0.08 W / m K.

Bulk and sprayed insulation

Main advantage bulk materials- ease of installation, as they are simply poured into the inter-beam space. The most common include:

expanded clay- balls of small diameter obtained by firing clay;
perlite- the rock is crushed and fired to obtain a porous structure. Lighter, but at the same time, quite expensive material;
ecowool- Made from cellulose. For fire resistance, it is treated with special solutions.
Styrofoam- light balls that are sold in bags.

Sprayed polyurethane foam – environmentally friendly, durable, durable (serves at least 30-40 years) insulation with good thermal performance. Energy efficiency comes from uniform application without joints and gaps. Application does not require special preparatory work, the foam fills all the bumps and voids, after hardening you can walk on it. The disadvantages of PPU include it relative high cost and the need to use special equipment for installation.

Which floors require insulation

The calculation of the thickness of the insulating material can be carried out independently according to SNiP II-3-79* "Construction heat engineering".

This takes into account:

climate zone- the average air temperature during the cold period and the duration of the heating period in the construction area;
material features is the thermal conductivity coefficient.

General principles of insulation

In preparation for the insulation of floors in wooden house should accurately measure the distance between the beams. According to this indicator, materials are cut. If a residential building is thermally insulated, then at the preliminary stage it will be necessary to remove all unnecessary items and debris from the attic. If there is an old insulation, it will have to be dismantled.

Biological damage on wood (fungus, mold) it is necessary to remove with an iron brush and treat these places with an antiseptic composition.

If the calculated thickness of the insulation is greater than the height of the beams, then they are additionally stuffed wooden slats. They are necessary to create an air gap. This is true with further flooring in the attic floors.

Arrangement of vapor barrier

Vapor barrier materials prevent the penetration of moisture into the beam structure and the insulation layer. Especially important is the arrangement of this layer over wet rooms: kitchen, bathroom, sauna. Experts recommend using strong reinforced polymer or membrane films. To reduce heat loss, foil materials are used. They are attached with a reflective surface down.

The best solution is to install a vapor barrier in the attic floor. continuous layer. During the construction phase, it is convenient to do this from the side of the first floor. The film is attached directly to the beams, if this is not possible, then laying is carried out in the inter-beam space. Material mounted overlap and to ensure tightness fixed with special tape.

Insulation laying

If several layers of material are used to insulate attic, interfloor floors along wooden beams, then it is important to take care of their installation in a checkerboard pattern, that is, the upper sheets should cover the joints of the lower ones.

When insulating floors on wooden beams, it is important to monitor the density of laying the material. Any gaps, gaps or voids can cause a decrease in the thermal insulation index of the structure. Joints between rigid polymeric boards can be filled with polyurethane foam.

Bulk materials evenly distributed in the inter-beam space, since it is important to observe the calculated thickness of the backfill.

Termination Processes

To protect the insulation from above is attached hydro, wind protection. It is laid with an overlap (10-15 cm), with mandatory sizing of the joints. Usually in the attic they equip floors from edged boards, you can also use chipboard, plywood, etc.

Conclusion

Thermal insulation of a wooden floor between living quarters and an unheated attic is a process that requires a lot of labor. It helps to reduce heating costs, create a comfortable microclimate in the house, and for greater clarity, we offer a meaningful video on the rules for warming the interfloor ceiling on wooden beams.

Since the roof of a cold attic only serves as protection against rain, snow and, in part, wind, Special attention it is worth giving the thermal insulation of the floor. Insulation of the attic floor is carried out using various thermal insulation 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

Most small houses and dachas with a cold roof, wooden floors are used, therefore 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. Because they usually maximum length 4 meters, then 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 load-bearing structures because of 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 obligatory overlap 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 as finishing If you want to use a leveling screed, 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 slabs of reinforced concrete, then this can be done in two ways: with the use of crates and without it.

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 the formation of a cold bridge through wooden blocks, 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. best performance in order to insulate the attic floor of the house, it has a 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

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, the insulation of the attic floor on wooden beams with foam plastic is not the best good idea. However, it can be used between non-combustible materials, for example, when laying as insulation on concrete slab with screed filling.

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. Operational properties extruded polystyrene foam is significantly better than that 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 to insulate the attic floor of the 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 special solution, the production 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 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 independent 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 one regarding cheap material, which can be used to insulate the attic floor in a private house - this 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.

The issue of building insulation is now more acute than ever. Most start with wall insulation, but they end there, however, as you know, warm air has the ability to rise and go through the roof, so the insulation of the attic floor plays an important role. As with all construction work, insulation should be carried out with high quality. But how to insulate the attic floor in order to get the maximum benefit?

When choosing a heater for the attic floor, it is important to take into account its heat-shielding properties, strength, and resistance to external factors. The type of overlap will also play a role: for concrete and hardwood floors have their own characteristics. So, how to insulate the attic floor?

Popular attic insulation

Types of heaters:

Basalt mineral wool.
Expanded clay.
Styrofoam.
Sawdust.

Mineral wool

Most often, attic floor insulation is carried out with the help of mineral wool. What are its features and why is this heater so popular?

Mineral wool is laid between the wooden beams of the attic floor

Benefits of mineral wool:

High thermal insulation. For example, to insulate the attic floor with mineral wool, the layer thickness is 3.5 times less than when using expanded clay.
Ease of material installation. This heater is not difficult to work even for those who are engaged in insulation for the first time.
Fire safety. Mineral wool is not easily flammable, therefore, in the event of a fire, it does not serve as a fast carrier of fire, which, for example, cannot be said about polystyrene foam.
Long operating period. If you properly lay the mineral wool, it will not roll down and will not create cold bridges.
Affordable price.

It is thanks to all these advantages that attic floor insulation with mineral wool is a widely used way to save heat in a room.

However, this heater also has disadvantages. In particular, due to its ability to absorb moisture, the mineral wool insulation layer may no longer provide the same thermal insulation as before. Also, when insulating the attic floor with mineral wool, it is important to observe safety precautions. Mineral wool fibers in contact with the skin can cause irritation, so you should work with it in tight clothing, glasses, a respirator and, of course, gloves.

Expanded clay

Another material for attic floor insulation is expanded clay. Although this insulation is rarely used, it still has a number of advantages.

Expanded clay - very popular in the earlier heat insulator

Expanded clay advantages:

The cost of insulation.
Good indicators of thermal insulation. However, to achieve a really good result, the thickness of the expanded clay layer should be about 35-40 centimeters.
Fire safety.

However, expanded clay as a heater also has significant disadvantages:

More weight than other heaters. The thermal insulation of a wooden attic floor creates a load on the beams, so when choosing expanded clay, this point should be taken into account.
Installation inconvenience. Raising a huge amount of expanded clay to the attic can cost a lot of effort.

Styrofoam

Styrofoam is one of the best materials for wall insulation, so some decide to use it for thermal insulation of the attic floor. And although the foam has advantages, it is still not recommended to use it.

Attic floor insulated with foam plastic from below

The advantages of foam:

Waterproof. This is a plus compared to the widely used mineral wool.
Affordable price.
Ease of installation. Lifting sheets of foam and laying on the attic floor is not difficult.

Despite these advantages, foam as a heater has a number of significant drawbacks.

Foam Disadvantages:

High flammability. If the fire reaches the heater, it is unlikely that the fire will be extinguished.
Intolerance to high temperatures. At a temperature of +60°C, the material deforms, at +80°C it begins to melt, which releases toxic substances, and at +210°C the foam ignites.
Fragility. The foam is able to crumble, which reduces its thermal insulation properties.

In view of these shortcomings, especially insecurity in case of fire, it is better not to use polystyrene foam as a heater for a wooden attic floor. After all, the combination of foam plastic with wooden beams is very dangerous. However, this insulation can be used for thermal insulation of concrete floors.

Sawdust

This method of insulation was very popular earlier, before the advent of modern thermal insulation materials. It is not without its advantages, although they are very insignificant compared to other heaters.

Sawdust Benefits:

The absence of toxic substances, as well as the natural origin of the insulation.
Relatively affordable price.

If we talk about the shortcomings of sawdust, we can note:

The need to prepare a solution consisting of sawdust, cement, lime and water. All other heaters are bought ready-made.
Large weight, which creates an additional load on the floor.
Large thickness of the insulation layer.

Important! After analyzing all the advantages and disadvantages of different heaters, many come to the conclusion that mineral wool is ideal option, because it has high thermal insulation properties, is fireproof, easy to install, and also has affordable price. As for its shortcomings, hygroscopicity can be compensated for by installing vapor barrier and waterproofing, and inconvenience when laying mineral wool - by observing safety rules.

Mounting process

Having decided on the material for thermal insulation, the question arises: how to properly insulate the attic floor? If we talk about mineral wool, then what density should it have and what layer of insulation will be the best?

The choice of layer and density of mineral wool

Warming with mineral wool is best done in two layers

In short, the larger the layer of mineral wool, the better. However, it must be remembered that mineral wool has its own coefficient of thermal conductivity. The lower this coefficient, the higher the thermal insulation properties, and, therefore, it is possible to lay a smaller layer of wool or have a greater insulation efficiency. Often, mineral wool with a thickness of 15–20 centimeters is used, however, a 30-cm layer of insulation can also be used to provide increased thermal insulation. It is also worth noting that with an equal thickness of insulation, two layers of mineral wool are always better than one.

You also need to pay attention to the density of mineral wool, because it can be different: from 30 kg / m 3 to 220 kg / m 3. Thermal insulation properties practically do not depend on density. A denser insulation is used for facades and floors under the screed. Mineral wool with a density of 35 kg / m 3 is also suitable for the attic floor, because the insulation will be on a horizontal unloaded surface.

vapor barrier

Since mineral wool tends to absorb moisture, you need to start the insulation with the laying of a vapor barrier material.

Vapor barrier - the first layer of insulation

Important! It is best to lay a layer of vapor barrier under the wooden beams, because otherwise, they will be very susceptible to rotting. Nevertheless, if it is impossible to put a vapor barrier film under the beams, they must be impregnated with solutions that protect against rotting and mold.

The best option is to lay a continuous layer of vapor barrier, but due to the size of the attic, this is not always possible, so all joints must be glued with special tape to ensure tightness. The edges of the vapor barrier must be raised above the level of the future insulation and glued with the same tape.

thermal insulation

It is necessary to work with heat-insulating materials in overalls

The next step is to install the heater. It must be laid so as to completely fill the entire space between the wooden beams. If we are talking about mineral wool, then it does not need to be pressed or squeezed. It should completely cover the space between the beams, leaving no gaps or gaps. The floor beams themselves will also not be superfluous to cover with heat-insulating material, because they can serve as a kind of cold bridges.

When laying mineral wool, it is very important to protect yourself, and especially your Airways from the ingress of insulation fibers. Therefore, you need to use a respirator, as well as gloves, goggles and long-sleeved clothing.

Waterproofing

We complete the insulation of the attic floor with waterproofing and subfloor installation

Due to the property of mineral wool to absorb moisture, waterproofing must be laid on top of the mineral wool layer. It is also necessary if it will be poured over the insulation concrete screed.

If the attic is constantly used, a subfloor can be made on top of such a heat-insulating "pie". In its role can be a concrete screed or OSB slabs. If the attic is practically not used, then you can simply lay the boards on top of the existing beams. Then, if necessary, go up to the attic, movement through it will not create difficulties.

As you can see, attic floor insulation is an affordable task, even for those who have never done it. It is necessary to decide on the material for thermal insulation, although most often it is mineral wool. When installing a heat-insulating "pie", it is important to remember the need for vapor barrier and waterproofing. This will achieve high results in the insulation of the attic floor.

Video: we discuss in detail the design of the floor

An overview of the structural details of the attic floor insulation device. What is a sufficient layer of insulation for a cold attic? What are the specifics of the work on laying the thermal insulation of the attic floor?

home » materials » How to insulate an attic with wooden beams. Cold attic floor insulation