Membrane for attic roof. Insulating the attic from the inside: possible problems and ways to solve them

Back in 1630, the architect Mansart proposed using attic space for residential purposes. This is how the attic appeared - comfortable room. And it will become even more comfortable if you insulate the attic from the inside. The key to effective thermal insulation is the following rules: creation of a continuous insulation contour, provision of waterproofing and vapor barrier, arrangement.

Materials used

Not all insulators are suitable for do-it-yourself attic insulation. Optimal choice– slabs made of stone wool. They are fire resistant and vapor permeable, do not deform and almost do not absorb water. And here polystyrene foam boards and builders try not to use fiberglass mats. The former cannot boast of fire resistance, the latter lose their thermal insulation properties over time.

Most often, in this case, lightweight materials are used so as not to put a large load on the main structures. Therefore, when making it, they prefer to use wood or a thin cold-formed metal profile.

During installation, you must not take the product by hand. exact size frame cells rafter system. If the insulator is calculated based on the size of the cell, it will not perform its functions: the material will “dry out” and small cavities will form through which the cold will seep.

When a slab of the selected insulation is taken with a reserve, it fits tightly into the space between the rafters and even after “drying out” the cotton wool fills the entire cavity.

We make thermal insulation of slopes

The roof, under which the attic space itself is located, is supported by a structure: sheathing and rafters, which are installed in increments of 600-1000 mm. Consequently, stone wool slabs are placed in spacers between the rafters. If the thickness of the insulation is greater than the cross-sectional height of the rafters, wooden beams treated with an antiseptic are attached to them using screws.

To remove moisture that has entered the under-roof space, an air gap is left between the roof and the insulator. If the roof is made of galvanized corrugated sheets, tiles or metal tiles, then the gap thickness should be 25 mm. If the roof is laid with flat sheets (asbestos-cement, galvanized, soft bitumen tiles), a gap of at least 50 mm is required.

Builders also recommend taking care of a layer of windproof, vapor-permeable material. If we are talking about building a house from scratch, a windproof film is attached over the rafters wooden blocks. In the case where the attic is being landscaped on an existing attic, the wind barrier layer is attached to the rafters either with nails or wooden slats.

Vapor barrier

It is very important when starting to insulate the slopes, to properly do the attic vapor barrier with your own hands. This is necessary to ensure that water vapor does not penetrate from the living space into the under-roof space.

As a rule, the roof does not allow water vapor to pass through well, so condensation forms on the inside and on the sheathing due to temperature differences.

Over time, this can lead to negative consequences: destruction of the frame of the structure, a decrease in the level of thermal insulation, and the appearance of leaks on the ceiling.

To prevent this from happening, the thermal insulation layer is additionally protected with a vapor barrier material (ordinary polyethylene film or a membrane specially designed for this purpose will do). He is laid with inside slabs with an overlap of 150-200 mm, and then secured with wooden slats.

The vapor barrier material must be airtight. By the way, some thermal insulation materials have a special base made of foil. It allows you to protect the roof from condensation: during installation, you need to make sure that the insulation is placed with foil inside the room.

Finishing

It will be correct to finish the attic only after all procedures related to the thermal insulation of the slopes have been completed. The inside of the attic floor can be finished with plasterboard, plywood, clapboard or boards.

The finishing material is attached to bars or to metal profiles. If the insulation is not equipped with a vapor barrier film, but with vapor barrier foil, the finishing material is fixed at a distance of 5 cm from the foil. This allows you to reduce heat loss.

It must be remembered that the outflow of heat in the attic occurs not only through the slopes, but also through the end walls (gables). Insulation of attic walls is carried out in two ways. The most effective is external (when the heat-insulating layer is located on outside pediment). This option is acceptable for houses built from timber, logs, brick and foam concrete.

But external insulation is not always possible. Then the attic floor is insulated from the inside. In terms of technology, it is not much different from insulating a conventional frame wall:

a windproof layer is installed on the frame beams, after which insulation is placed;
if the frame is less thick than the insulating layer, then additional bars are installed;
After the installation of the insulator is completed, the wall is covered with a vapor barrier.

Please ensure that the vapor barrier layer is not interrupted either at the gable or on the slopes. This can be achieved by fastening the panels of vapor barrier film overlapping.

Working with stone walls

For stone walls you'll have to make the system from scratch. An alternative to the above insulation materials is the use of blocks made from alabaster chips. The best option is wood fiber boards, that is, fiberboard. Fiberboard has many advantages. So, one product with a thickness of 1.2 cm is similar to a 4.5 cm brick. In addition to heat-insulating properties, it is distinguished by sound-proofing properties. The slabs are treated with an antiseptic substance, so they are not susceptible to microorganisms or mold.

In general, fiberboard is a rather brittle, lightweight and soft-to-touch material. Outdoor area The product has a smooth surface, and the inner one is corrugated. The slabs do not react to sudden temperature changes, are quickly cut into pieces and do not deform under the influence of different loads. Wallpaper rolls are glued to the outer area of the insulation, which will create home comfort on the floor.

The correct way to insulate gables with wood fiber boards is as follows:

a slab measuring 250x122 cm is lifted to the desired area, after which it is strengthened from below with plank supports shaped like the letter “T”;
the slab is nailed to the wall surface. The length of the fastening elements is more than 3.5 cm.
Under the heads of the nails, special plates measuring 1.5 * 1.5 cm made of thin aluminum - “duralumin” - are placed.

Fastening is carried out in a checkerboard pattern and so that the caps are buried in the material, otherwise the surface will not be smooth and this will ruin the finish.

Working with the floor

When insulating the attic, it makes sense, in addition to the gables and ceiling, to insulate the floor surface. There are two popular methods. The first involves dismantling the old coating and then laying two layers of roofing felt. Following them are placed fibreboards of certain brands. We are talking about M-20 and Pt-100. At the end, the finished floor is laid again.

The second method is based on the use carpets special type. First, the baseboards are dismantled, and fiberboard is nailed on top. Carpet materials are glued to the slabs. Before gluing, it is necessary to keep the products unfolded in a dry place for 14 days - this is exactly the time needed for shrinking and leveling.

Another option for preserving heat is to place another layer of thermal insulation under the already installed layer. This is done as follows:

on interior lining In the attic, a frame made of beams is installed, between which insulator slabs are placed (stone wool is ideal). The height of the bars should be equal (or less) to the thickness of the insulation layer;
the thermal insulation layer is protected by a vapor barrier material - it is attached to the frame bars.

Interior finishing

The inside of the attic can be finished with clapboard, plasterboard or plywood. It must be remembered that when using this particular attic thermal insulation technology, the usable area of the room, as well as its height, is significantly reduced. The advantage is that you don’t have to dismantle the roof, so you can get to work not only in summer, but also in winter.

Insulating the attic also involves insulating the floor below it. There are times when, as optimal option A combined approach is suitable. It consists in insulating the ceiling on top of the existing thermal insulation. Inclined surfaces attic room are finished from the inside. In both cases, we must not forget about the thermal insulation of the gables.

So, insulating the attic from the inside is perhaps the only way to obtain a comfortable microclimate. In addition, correctly selected thermal insulation will allow you to pay less for heating even in very cold winters.

P When deciding to operate an attic, a private homeowner should first of all think about insulation and vapor barrier of this room. The comfort of living in the attic, as well as heating costs, depend on the competent execution of these works. We will talk about how to do a vapor barrier in an attic with your own hands in this article.

Condensation or water vapor is the worst enemy of the rafters and roof insulation. The scope of work for attic repairs can be compared with new construction, which indicates the importance of monitoring work on vapor barrier equipment. The attic vapor barrier is installed from the inside of the room.

When designing and constructing attics, it is necessary to take into account two main mechanisms for the movement of water vapor and, as a consequence, humidification of the structure - diffusion and convective transfer of vaporous moisture.

What is diffusion

Diffusion is the movement of vapor from an area with high partial pressure to an area with lower pressure.
In the cold season, this transfer occurs from the warm interior of the attic towards the cold street with low partial pressure. In summer, the direction of diffusion transfer changes, and water vapor, which is in large quantities in the outside air, tends to enter the relatively cool and dry attic room.

How more difference temperature and humidity between the street and the room, the stronger the diffusion flow. In the path of this flow is the entire attic structure - diffusion roofing film, insulation, vapor barrier material and interior decoration. Therefore, the diffusion permeability of these materials determines the amount of vapor passing through diffusion. Since the roofing film and mineral insulation have very low resistance vapor permeability, these layers can be ignored and the vapor permeability of the structure can be assessed only by the properties of the vapor barrier material, which is expressed by the indicator Sd [m] - the equivalent thickness of the resistance to water vapor diffusion.

What is convection

Convection is the uncontrolled movement of air and the water vapor it contains through unconsolidated layers insulating materials. The intensity of this transfer is influenced by the wind speed outside the building and the size of the cracks. IN modern designs attics with one ventilation gap and a diffusion under-roof membrane and vapor barrier perform the function of air insulation. Both protective layers are reduced to a safe level or completely eliminate the convective transfer of moisture contained in the warm air of the attic (exfiltration) during the cold season and the infiltration of external humid and hot air into the attic in the summer.

As a rule, in real construction conditions both mechanisms of humidification are present, but if diffusion transfer depends on the choice of vapor barrier and partial pressure difference, then convective transfer is 100% dependent on the quality insulation works and from the complete set with system accessories - adhesives and tapes. When comparing diffusion and convection in terms of moisture in the structure, convection is a disproportionately more dangerous process due to the amount of water vapor entering the roof structure.

Study of air movement in the attic

The Institute of Building Physics (Germany, Stuttgart) in 1989 conducted research and comparative calculations of moisture transfer by both processes, which were subsequently confirmed by laboratory tests. The results were published in the German Construction Journal (Deutsche Bauzeitschrift, No. 12/89, p. 1639). Studies have shown that, depending on the pressure difference between the street and the interior of the attic, convective moisture transfer is hundreds of times greater than humidification due to diffusion. Main negative consequence moistening the thermal insulation results in a significant reduction in the heat transfer resistance of the entire structure, which leads to increased operating costs.

In addition, conditions are created for moisture and mold damage. load-bearing structures roofs (wooden and metal). Increased breathability significantly reduces air quality during interior spaces home due to the transfer of both construction and external dust. The microclimate and comfort of living in the attic are deteriorating. It is not uncommon for homeowners to complain about “cold from the floor” when the heating of a private home is fully turned on. And the source of cold can be breathable walls, especially if they are framed, ceilings, wall and floor junctions, windows, electrical appliances, heating equipment pipes and wiring. It’s no wonder that one of the common sayings among roofing inspectors is “Outlet Tornado” when a draft speed of more than 4-6 m/s is recorded.

Numerous tests carried out in various countries, determine highest speed air flow of 0.2 m/s, which is not perceived by humans as uncomfortable. Maximum permissible speed European standards is 2 m/s. In private houses equipped with climate control systems, it is especially important to provide high-quality protection from convective air movement, since a breathable roof and walls significantly reduce the efficiency of their operation and also lead to increased costs for maintenance and air conditioning of the house. Practical experience roofing works in Europe and Russia fully confirms that the greatest danger to an insulated roof is represented by loose overlaps of vapor barrier and its junction with walls and other structural elements roofs. The job of a professional roofer is to eliminate or minimize the uncontrolled movement of air and the water vapor it contains through the roof structure.

Selection of vapor barrier material

Currently, designers and roofers have at their disposal wide choose vapor barrier materials; moreover, the best developers and manufacturers offer a system of vapor barrier materials that combines films, tapes and adhesives, as well as technical solutions. Typically, the type and characteristics of vapor barriers depend on design features attic and temperature and humidity operating conditions of the room.

Vapor barrier materials

Single layer films

Single-layer films made of polyethylene (advantages: transparent material allows you to easily control the quality of insulation, high Sd (more than 100 m) with a thickness of more than 200 microns, sufficient elongation at break; disadvantages: low strength in places where the stapler is attached with staples).

Reinforced multilayer films

Reinforced multilayer films made of polyethylene (advantages: transparent material and increased strength; disadvantage: low Sd due to the strong thinning of the layers in the places where the reinforcing mesh is interlaced). In Europe, reinforced films weighing at least 200 g/m2 are used to a limited extent.

Polymer woven films

Polymer woven films with a single layer lamination (advantage: high strength; disadvantages: not transparent material, low Sd due to a thin continuous layer of polymer and very low elongation at break).

Multilayer films made of polyethylene

Multilayer films made of polyethylene with a reflective layer (advantages: high strength and diffusion resistance Sd > 100...150 m, heat conservation due to its re-reflection into the attic, self-adhesive tapes along the edge of the roll; disadvantage: opaque material).

Self-adhesive roll polymer-bitumen materials

Self-adhesive roll polymer-bitumen materials are very simple to use - they are glued to a solid base (for example, OSB or concrete) over a layer of primer, can be used on steep surfaces and do not require additional gluing of overlaps with tapes.
OSB - used as a vapor barrier only in rooms with normal humidity and in houses without wet finishing works. The main segment of such vapor barrier is frame and prefabricated houses or houses insulated with blown-in cellulose wool. It is necessary to use tapes for gluing overlaps and junctions. On roofs with complex geometry, the use of OSB vapor barrier is associated with very high complexity of installation and the cost of additional accessories. Therefore, OSB is recommended for use on houses with simple geometry, and in wet rooms of such houses it should be additionally laid film vapor barrier. It is not allowed to use OSB on logs and timber houses due to the large settlement of the walls.

Adaptive attic vapor barrier

Adaptive attic vapor barrier with variable vapor permeability made of polyamide is used only for renovation of rooms with normal humidity. Its use in new construction or reconstruction of buildings with high humidity is not allowed.

During new construction or renovation of pitched roofs, only the use of a system solution can guarantee high reliability and durability of the roof. Therefore, the use of films alone, even the best ones, will not answer modern requirements the customer – to protect his roof from bad weather and provide comfortable living conditions. Ultimately, the home owner evaluates the quality of roof insulation based on the comfort of living and the cost of operation.

Taking into account the constant increase in energy, protecting insulation from steam and convective air exchange is becoming one of the most important from the point of view of the homeowner’s costs for heating and air conditioning his home. Most often problems manifest themselves in the most difficult places roofs – at junctions with walls, pipes and skylights, in valleys and ridges, when constructing roof penetrations and in places where rolls overlap. Therefore, the use of adhesives, connecting and sealing tapes is a necessary factor for solving problems in such critical areas of the roof. A wide variety of accessories allows the professional roofer to choose the most suitable way unit design depending on the quality of the surface and conditions of use.

Quality control of vapor barrier and air permeability

The installation of a vapor barrier is a hidden work, so it is necessary to check and accept the work before installing the finishing material. It is recommended to take photographs or videos of completed work. Particular attention should be paid to overlaps and junctions of vapor barriers, as well as to the sealing of utility lines.
Unfortunately, the laying of pipes and wiring most often causes damage to the vapor barrier layer and subsequent problems with the formation of condensation and moisture in the entire structure.

However, carrying out only a visual inspection cannot guarantee a reliable result, since it is impossible to identify all defects. In Europe, instrumental testing has long been practiced, which provides almost 100% reliability of inspection and detection of defects. In practice, the simplest and most frequently used visual ways using powder, smoke (smoke generator) or water mist (ultrasonic steam generator).

These tools are only indicators that identify problem areas. To quantify air permeability, thermal anemometers are used, which are capable of measuring the local speed of air flow at a specific location in the vapor barrier. A general assessment of the tightness of the vapor barrier of the entire house is given by the BLOWER DOOR method (see the article “BLOWER DOOR Technologies”, ROOFING, 01-2008).

Conclusions:

Abundance on Russian market vapor barrier films of various brands, it would seem, makes it possible to ensure that the attic vapor barrier works without problems. However, really professional quality can only be achieved by using an insulation system:
A film correctly selected for a specific roof structure and the temperature and humidity conditions of the building;

A residential attic space is called an attic. It must be warm and suitable for year-round use, so the roof is insulated. Fiber insulation materials that are safe for humans are used as thermal insulation materials for residential premises. They have a number of advantages, but when wet they reduce their performance. This can happen due to roof leaks or condensation. In addition, over time, moisture leads to the destruction of materials, including the interior decoration of the attic, and to the appearance of mold. The article will discuss which waterproofing to choose for the attic.

The task of attic waterproofing is to protect the under-roof space and the room from moisture leakage due to rain or melting snow. Often moisture penetrates due to damage to the roof or due to a loose ridge and snow blowing under it.

Water getting on the insulation negatively affects its qualities, and with prolonged exposure leads to destruction. Traditionally, fiberglass treated with bitumen was used for this. But today modern materials with better qualities have appeared. In addition, they are much more convenient to work with. First of all, we are talking about membrane films, which not only perform the function of waterproofing, but also prevent the formation of condensation, have the function of wind protection and vapor protection.

Vapor barrier and wind protection of attic roof

Due to air movement and steam pressure, condensation occurs. This is especially true in winter, when there is much more vapor in a warm room than outside. As a result, diffusion occurs, in which steam penetrates into the under-roof space.
When there is ventilation in the house, this leads to active air movement and increased pressure. Air and steam tend to escape through cracks or joints of materials.
Finishing materials, which are most often used to clad walls and ceilings, are vapor permeable and do not prevent moisture from penetrating the roof structures. Therefore, it is advisable to protect the thermal insulation from the inside with polyethylene films, membranes or foil films.

The film for waterproofing the attic from the inside is produced in wide rolls, which allows you to keep the number of joints to a minimum. A vapor barrier will only work if the fabric is absolutely intact, so all joints are made with an overlap, and the connections to the pipes are additionally glued.
The recommended overlaps are 10 cm and should be on the frame element in order to secure them most firmly with a construction stapler or lath. Minimum thickness films 0.15 mm.
If communications are planned to be carried out through the film, they must be tightly glued with reinforced tape.
When is thermal insulation performed? pitched roof attic, it is important to protect the insulation from cooling from blown cold air or wind. Special slab insulation, which has the highest compressive strength, copes well with this function. In terms of their vapor-permeable properties, they do not differ from other slabs, but the best way resist the wind. This insulation retains heat better and is an excellent soundproofing material. This is especially important if the roof is made of metal.

Tip: wind protection, vapor barrier and waterproofing of the attic are necessary when insulating it. Any roofing material on a pitched roof is not a continuous covering, so there is always a risk of moisture penetration from precipitation.

Materials for attic waterproofing

For waterproofing, films are used that are attached directly under the roofing material. These include:

polypropylene films;
non-woven membrane materials;
polyethylene films that do an excellent job of hydro- and vapor barrier in the attic.

Often these materials are interchangeable. Thus, vapor barrier films are used as under-roof waterproofing, and waterproofing films are used as a vapor barrier from the inside of the room.

Advice: there is so-called simple waterproofing, but for the attic it is better to use waterproofing material with anti-condensation effect. It has an absorbent fleecy layer that functions to retain drops of water, thereby preventing it from reaching the insulation.

Polyethylene film for attic waterproofing

Modern polyethylene films designed for waterproofing mansard roof, are reinforced with fabric or a special mesh. This material acquires high strength and does an excellent job of retaining moisture from the outside and steam from inside the room.

There are two types:
1. perforated. Its surface is covered with microholes. Which are able to retain moisture, but not steam. Therefore, its function is waterproofing;
2. non-perforated. It has a monolithic fabric that copes well with vapor barrier.
Regardless of the type used, a ventilation gap of 5 cm must be provided in the roof pie.
In addition to traditional films, roll polyethylene with an aluminum layer is on sale. It can be made of foil or sprayed aluminum. This reflective layer allows you to additionally retain heat in the room.
The best quality are foil polyethylene films such European manufacturers, like POLYCRAFT, JUTAFOL N AL, DELTA-REFLEX.
Their moisture-proof properties are very high, so they are suitable for use in roofs of any design.

Polypropylene film for attic waterproofing

Reinforced polypropylene films compare favorably with their polyethylene counterparts due to their much higher strength. They're not afraid ultraviolet rays and will reliably protect the attic space from precipitation.

One side of this film has an anti-condensation coating. In this way, it protects the thermal insulation material from the formation of condensation. This coating is made from viscose fibers with cellulose. It is characterized by high moisture absorption and ability to retain it. According to experiments, the anti-condensation layer absorbs a large number of water and, holding it, does not form drops, which is guaranteed to protect the insulation and roof structures from getting wet.
When the conditions that caused the condensation disappear, the air flow from the vent will quickly dry the material.
When using such films, it is important not to mix up the sides; the glossy layer is placed on the outside, and the absorbent, rough layer is placed towards the insulation.

Anti-condensation films for attic waterproofing

This is a type of waterproofing material, one side of which is rough. It absorbs moisture formed by condensation and retains it. When water accumulates, it does not form into droplets. And it is securely held by the material until air circulation in the ventilation gap between the film and the insulation brings it out.

In addition, anti-condensation films have excellent moisture-resistant characteristics and will protect the ceiling from water leaks that could get through cracks in the roof.

Vapor barrier films for attic waterproofing

It protects against small particles of water and steam. It only works if the fabric is solid, and if there is the slightest tear or gap at the joint, moisture will penetrate into the insulation.
Not only the joints of the fabric are sealed, but all places where the vapor barrier film adjoins the walls and communications are sealed.
When using a vapor barrier in the attic, between it and finishing material There should be a ventilation gap of 2-3 cm to prevent the formation of condensation on the inside of the material.
It also has 2 sides, the manufacturer indicates on the packaging how to position it correctly.

Diffusion membrane for attic waterproofing

This is a modern breathable material that is completely vapor permeable, but at the same time protects the roof from precipitation, condensation and wind. Hence the second name - vapor-permeable wind-moisture-proof membrane.
It is made in a non-woven way from synthetic fibers. Its main advantage is the saving of under-roof space, because the height of the ceilings of the attic floor is usually small. This is possible due to its characteristics and the ability to attach directly to the insulation, without installing a ventilation gap. You can use the resulting space differently - add an additional layer of thermal insulation.

They are most often used not only in the construction of new houses with an attic floor, but also when arranging a cold attic into a living space. In this case, there will be no need to reconstruct the rafter system.
The initial cost of diffusion membranes differs slightly from the price of other vapor barrier materials. But during operation it will show maximum energy efficiency and allow you to save on heating.

How to choose waterproofing for the attic

The material used to waterproof the roof in the attic depends on several indicators.

First of all, this is the angle of the roof. If the angle is sharp, then it is enough to install an under-roof windproof or vapor barrier membrane. A roof pie whose slopes are more gentle will already require a waterproofing anti-condensation film.
When there are 2 ventilation gaps in the attic roof structure, simple waterproofing materials are used. And with a single ventilation circuit, preference is given to diffusion membranes.

Since we are talking about waterproofing a residential heated attic, it is better to provide two layers of moisture-proof films. For example, with a conventional vapor barrier film and windproof membrane. Or with only one vapor barrier anti-condensation membrane, but with two ventilation circuits.

Advice: the best solution will be the design of insulation and waterproofing of an attic roof with 3 films. If we start from the living space, the pie looks like this: drywall, vapor barrier film, insulation, windproof film, ventilation gap, plastic film, ventilation gap and roofing material.

The film should be stored in a dark, closed room. If it has already been mounted on the roof or walls, then it must be closed immediately facing material. The membrane is destroyed quite quickly under the influence of ultraviolet radiation and wind. Indoors, non-woven vapor barrier should not be located near lamps or heaters. This also leads to the destruction of its structure.

How to waterproof an attic with your own hands

Since it is impossible to insulate an attic without waterproofing, this process must be considered in its entirety.

The roofing material does not have heat-preserving qualities. Therefore, if we are talking specifically about a residential attic, then it should be used only environmentally safe materials. Most often this is mineral wool or glass wool. Both of these materials have high heat and sound insulation properties. This is especially important if the roof is made of metal. But all these qualities are reduced to zero when the insulation gets wet. Therefore, it is necessary to properly think through all the components of the design.
If the house is new, then it is easier to carry out work from the bottom up, starting from the lower layers and ending with the roof. If the house has already been built, and the roof is insulated during operation, then there is no choice and the work proceeds in the opposite direction. Consider the option of working in a house under construction.

A vapor barrier film is nailed onto the roof rafters from below with a tight tension using a construction stapler. To prevent the staples from tearing the material, it is pressed on top of the fastenings to each rafter with a lath, which is mounted on self-tapping screws (in the case of a wooden structure).
In the resulting cells, the walls of which are rafters, and the bottom is a vapor barrier, thermal insulation material is laid in a checkerboard pattern with overlaps. With a thickness of 5 cm, 3 layers are made.
The top is covered with windproof waterproofing. The top is also fixed with slats. Their thickness will provide the necessary ventilation gap. The width of the ventilated gap directly depends on the roof material. So, if you choose corrugated sheeting, metal tiles or ondulin with a profile, then it is enough to leave 2.5 cm for air flow. For flat material, the ventilation circuit between the waterproofing material and the roof sheathing is provided at least 5 cm. Ventilation will be carried out from the roof eaves to its ridge.
Practice shows that the best effect in protecting the insulation under the roof can be achieved by using modern materials from trusted manufacturers, such as Izospan or Tyvek. Using regular polyethylene film gives worse results due to the formation of condensation, and the old way waterproofing with roofing felt, according to professionals, is unacceptable.

Advice: all seams and joints of films are taped with tape; this is the only way to guarantee that moisture will not penetrate inside.

DIY waterproofing

Do you need waterproofing in an unheated attic?

If the house is being built taking into account that in the future it is possible to convert the attic into an attic, then waterproofing will significantly speed up this process. But, if there is no such desire, is it necessary to install protection from moisture and wind under the roof without thermal insulation material?

Even if there is absolute confidence in the quality roofing material, in its correct installation, which guarantees the protection of roof structures from the penetration of moisture into them from slanting rain or blowing snow, pull them onto the rafters waterproofing film still necessary. Since moisture penetrates not only from the outside, but also from the inside in the form of condensation. Water droplets form on the roof covering and lead to its corrosion.
For an unheated attic, you can use any type of waterproofing materials: polyethylene film, diffusion membrane or anti-condensation film. Preference is given to anti-condensation materials, since they are cheaper than diffusion materials. And unlike polyethylene films, able for a long time hold the condensation until it evaporates naturally.
Condensation forms especially often in cold attics when communications such as fireplace pipes, chimneys, etc. pass through them. Even if they are securely closed with thermal insulation material, some of the heat will still pass out, which will lead to a temperature difference and the formation of condensation.

If you still plan to convert the attic into warm attic, then waterproofing must initially be carried out using diffusion materials.

The attic in the house has its advantages and disadvantages. Which? About this As the voting results show (), a house with an attic attracts approximately 50% of readers.

Work on insulating the attic is carried out either from above before installing the roof covering, either from below, after the house is protected from precipitation.

The first option is from above, it is more convenient to install, and allows you to carry out work faster and with better quality.

With the second option - from below, you can postpone the work and costs of arranging the attic until later.

The designs of insulated roofs in both cases are somewhat different.

Insulating the attic from above

In this article, we will consider the use of steam-wind-moisture barrier membranes in the construction of an insulated roof of an attic floor using the example of a system protective materials brand Izospan. You can read about the materials of this system in the article.

Installation of an insulated attic roof

1. Roof covering
2. Wind- and moisture-proof film Izospan AS, AM
3. Counterrail
4. Insulation
5. Vapor barrier Izospan B
6. Rafter
7. Interior decoration
8. Lathing

Scheme for protecting attic insulation from wind, moisture and condensation in Fig. 2

Wind and moisture protection of attic insulation

Fig.2. To protect the attic insulation from wind, moisture and condensation, a ventilated gap is arranged, and films and Izospan membranes are laid below and above.

Why protect insulation from wind?

Mineral wool insulation, which is usually used for roof insulation, has an open porous structure.

Air moving in the ventilated gap easily penetrates the insulation, blowing heat out of it. The effectiveness of thermal insulation due to air infiltration can be reduced by almost half.

In addition, air moving under the influence of wind in the gap tears off and carries away particles of insulation. Weathering of the insulation occurs - over time, its density and thickness decreases, the insulation becomes a source of dust, which can penetrate into the house.

To prevent these processes, the insulation on the top side of the ventilated gap is covered with windproof, vapor-permeable material.

In addition, the wind-moisture-proof membrane (item 2 in Fig. 1) protects the insulation and load-bearing structural elements from under-roof condensation, snow and atmospheric moisture, which can be blown into the gaps of the roofing covering or penetrate into the joints of roofing sheets due to capillary suction.

The wind-waterproof membrane should not prevent steam from escaping from the insulation (vapor permeability of at least 750 g/m 2 per day).

In the construction of an insulated roof, it is recommended to use vapor-permeable roofing membranes Izospan AM or Izospan AS as waterproofing and wind protection. Materials Izospan AM and Izospan AS laid directly on the insulation without a ventilation gap between them.

Izospan AM and Izospan AS are not intended for use as a main or temporary roofing covering for the period of installation.
Izospan AM and Izospan AS are laid with the white side facing the insulation.
When installing an insulated roof, Izospan AM (Izospan AS) is rolled out and cut directly on top of the insulation. Installation is carried out with horizontal panels overlapping, starting from the bottom of the roof. Overlapping panels at horizontal and vertical joints - at least 15 cm.

The stretched material can be additionally strengthened on the rafters with brackets using construction stapler.

On top of the material, 4x5 wooden antiseptic counter-battens are attached vertically along the rafters. cm on nails or screws. The place of the vertical overlap or the junction of two horizontal panels must be pressed against the rafters with a counter batten.

Lathing or continuous plank flooring is mounted along the counter-battens, depending on the type of roofing.

For weathering water vapor and roof condensation a ventilation gap must be provided between outer side material Izospan AM (Izospan AS) and roofing covering for counter rail thickness 4-5 cm.

In addition, to ensure ventilation of the under-roof space ventilation holes are provided in the lower part of the roof and in the ridge area for air circulation.

The material Izospan AM (Izospan AS) is fastened in a tense position so that water can roll freely over its surface. The bottom edge should provide a natural drainage of moisture from the surface of the membrane into the gutter.

Vapor barrier for attic insulation

Vapor barrier film(position 5 in Fig. 1) performs several functions at once:

Protects the insulation from penetration of water vapor from the attic room. From the article you can learn why, without a vapor barrier, insulation will accumulate moisture and collapse.
In addition, vapor barrier performs another function - it reduces heat loss.
The material protects the living space from the penetration of microfibers (dust) of the insulation.

Izospan B used as a vapor barrier in insulated roofs of exploited attics with various types roofing covering.
When installing an insulated roof, the Izospan V vapor barrier is mounted on the inside of the insulation on the rafters or along the rough sheathing using a construction stapler or galvanized nails. Installation is carried out from bottom to top with horizontal panels overlapping with overlap at horizontal and vertical joints of at least 15 cm.

When decorating a room with clapboard (plywood, decorative panels etc.) the vapor barrier is secured along the frame with vertical antiseptic wooden slats 4x5 cm., and when finishing with plasterboard - galvanized profiles.

The material is installed with a tight fit with the smooth side to the insulation, with the rough side down. The interior decoration of the room is attached to a slatted frame or galvanized profiles with a ventilation gap of 4-5 cm.

To ensure the tightness of the vapor barrier, it is recommended to fasten the panels of Izospan B material together with Izospan KL or SL connecting tape. Places where Izospan materials meet wooden, concrete and other surfaces are glued with Izospan ML proff adhesive tape.

Instead of Izospan B, Izospan RS, Izospan C or Izospan DM can be used as a vapor barrier when installing an insulated roof. The installation diagram is similar.

Heat-reflecting vapor barrier for attic insulation

Can be used as a vapor barrier heat reflective vapor barrier: Izospan FS; Izospan FD And Izospan FX. The material is mounted on the inside of the insulation (on the rafters or along the rough sheathing using a construction stapler or galvanized nails) with the metallized surface facing the room.

There must be an air gap of 4-5 in front of the metallized surface of the membrane cm. Only in this case does it happen reflection of heat flow, which increases thermal resistance coverings. Installation is carried out with horizontal panels overlapping, starting from the bottom of the roof. Overlapping of material at horizontal and vertical joints - at least 15 cm(Izospan FX - end-to-end).

Vapor barrier sealing

The vapor barrier layer prevents the insulation from getting wet. In places with defective vapor barriers, the insulation becomes saturated with moisture in winter. These places begin to freeze, fungus and mold appear on the walls, and the insulation itself gradually deteriorates.

Careful sealing of the vapor barrier layer is a necessary condition for long and reliable service of thermal insulation and wooden roof parts. The same thing happens if water gets into the insulation from above. But developers, due to misunderstandings, often neglect the threat of moistening the insulation from below, from inside the room.

TO wooden parts The vapor barrier film is secured using staples with a stapler. It is glued to the metal profiles of the sheathing with double-sided tape. The vapor barrier film is laid with 10 cm. overlap. The film should not be stretched too much, since the film changes its size when the temperature changes.

The joints of the film are glued with tape made from a material with a similar coefficient thermal expansion. The junction of the film to the walls is more reliable press with planks and apply sealant underneath them to the wall, since adhesive tapes do not adhere well to rough surfaces.

It is more reliable to make film joints over a hard surface, where, in addition to gluing, the joints can be pressed with spacers, sheathing bars, secured with staples, etc. Passages through the vapor barrier of chimneys and ventilation pipes are also carefully sealed. Don't neglect sealing plumbing piping and electrical wiring.

Choosing insulation for the attic

To insulate the attic, it is recommended to choose fireproof mineral wool insulation. In summer, the roof can heat up to 60 degrees C, and in winter, up to 25% of the heat can escape through a thin layer of wet insulation. Therefore, it is so important to lay a sufficient layer of insulation and prevent it from getting wet.

Modern energy saving standards recommend providing the attic roof with a heat transfer resistance of 4-5 m 2 *K/W. In order to obtain the economically justified heat transfer resistance required by the standards, it is necessary to lay layer of mineral wool insulation 20 - 25 thick cm.
How to calculate the thickness of attic insulation

The height of the roof rafters, as a rule, does not exceed 15-18 cm. Additional layers of thermal insulation are placed between the bars of the internal sheathing, or bars of the required height are nailed to the rafters from below.

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Soundproofing the attic

In addition to good thermal protection, the outer fencing of the attic must provide sufficient sound insulation of the attic rooms from airborne noise. People sleeping in the attic should not be awakened by the impact of raindrops or hail on the metal roof covering.

Therefore, the external fencing of the attic is subject to fairly stringent sound insulation requirements.

In accordance with current standards, the airborne noise insulation index of the external fence of the attic - Rw, must be at least 45 dB. The same mineral wool insulation is used as sound insulation and against airborne noise as for thermal insulation.

To achieve this indicator in the external enclosures of the attic the thickness of mineral wool sound insulation must be at least 250 mm. If the thickness is less, then the sound insulation will not meet the standards. Thus, the thickness of the mineral wool thermal and sound insulation of the attic is selected based on two conditions: thermal insulation and sound insulation. The thickness is the greater of the two indicated.

Insulating the attic when working from the inside

Features of the attic insulation design when performing work from the inside, under the installed roofing, are clearly visible in the figure below (to zoom in, press the Ctrl and + keys simultaneously):

If the overlap top floor made in house wooden beams, then the floors and partitions in the attic should be light in weight and provide the necessary sound insulation. In this case, it is best to make it with gypsum fiber sheets (GVLV) or other boards, and also install it. Just such an option is shown in the figure.

Note, frame partition should cut through the attic sheathing as far as possible, and the base of the partition should rest on the subfloor. This design will prevent sound transmission to the adjacent room bypassing the partition, through the finished floor covering and attic cladding.

If special measures are not taken, then soundproofing of attic rooms with frame external walls, partitions, floors and ceilings will be insufficient.

If the ceiling of the upper floor in a house with an attic is made of reinforced concrete slabs or, then on such a floor it is more profitable to lay partitions made of brick, as well as light gypsum or concrete building blocks.

Watch the video, which clearly shows the thermophysical processes in an insulated roof and the basic installation rules. While watching the film, remember the need for wind protection with mineral wool insulation.

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Quite often in modern life, there is a need to use all available space for a comfortable stay. The improvement of the attic space deserves special attention.

As practice shows, from the attic you can make excellent living room or living room. The disadvantage of these rooms is that it takes a lot of effort to create comfort and coziness. For attic spaces, a slightly different insulation option is required, as well as protection against leakage and fungus formation.

Modern construction companies are able to turn any attic into a well-equipped living room in the shortest possible time. The downside is that such services will cost you a pretty penny, which is not always affordable for the average citizen. But don’t despair ahead of time, because high-quality waterproofing the attic space can be built independently.

The attic floor is known to be most susceptible to heat loss. That is why the choice of materials must be taken seriously special attention. In addition, the space in this room has the largest area of contact with the street, which introduces additional difficulties. To avoid problems with roof leaks and to avoid damage to the furnishings of the room, high-quality waterproofing is required.

Insulation of areas of this type is carried out in a certain sequence, and it is necessary to use only quality materials. Otherwise, there is a risk of doing all the work in vain. When selecting a material, you should pay attention to its moisture-proof qualities.

Also, its behavior during temperature changes deserves special attention. It is desirable that when heated the material does not expand, and when cooled it does not contract and has elastic properties.

At the moment, construction markets offer a huge abundance of waterproofing materials. Their main differences lie in cost, installation option, as well as some physical characteristics. Typically, waterproofing an attic roof is done using roll-type materials.

Often, for such work, waterproofing perforated films with anti-condensation characteristics or films - membranes made of polymers are used. When installing any waterproofing material, a strict sequence of certain actions is observed.

A similar point when carrying out work is to ensure a small gap between the film and insulation, which serves as a space for ventilation. This nuance is not required for all similar materials.

Most suitable examples For waterproofing work in the attic, the following materials are used:

The polymer-bitumen coating is based on polyester or fiberglass. The material is available in in roll form. This type of waterproofing coating is a more modern analogue of roofing felt with better effects.
. For such a product, there is no need to leave a gap between the waterproofing and insulation, this is due to high vapor permeability. Most often, such membranes are used for waterproofing roofs with complex geometry.
The most common material is . First of all, this is due to its low cost and excellent waterproofing qualities. Widely used for pitched roofs.
With help modern technologies, was developed new way Waterproofing involves spraying a special insulating layer onto the inside of the roof. For such work, polyurethane foam is used. The main task of such spraying is insulation, but due to the specific composition, it has excellent waterproofing qualities. It is worth noting that spraying is expensive and is not always affordable for the average buyer. In addition, to use it, you will additionally need to use special equipment.

Material mounting options

During the final construction work, when it comes to the roof, the installation of waterproofing materials is carried out immediately before the roof covering is laid.

It is necessary to carefully glue the joints to increase the tightness. It is very important to create the maximum possible tightness so that the film does not burst due to temperature changes. When using film, do not stretch it too much. The material is attached directly to the rafter supports or to the floors, after which the sheathing is laid on top of it.

If the attic is insulated and insulated after construction work, then waterproofing material is sewn from the inside. In this case, the material used is attached to the rafters using a construction stapler. All joints, as in the previous case, are glued to create the best tightness.

Recommendations for proper waterproofing of an attic roof

To achieve the best result, the waterproofing material is laid in compliance with all installation technologies. Next, once the waterproofing material is installed correctly, the installation of a thermal insulation layer follows.

For achievement best quality, it is advisable to carry out work in the following sequence:

When waterproofing the attic floor, it is very important to achieve the maximum possible tightness of the moisture protection layer. To do this, the taped joints are inspected for possible gaps. The waterproofing coating used must cover the entire surface of the roof. It is necessary to ensure the maximum possible adhesion of the material to all elements that have access to the roof.
To create a gap between the waterproofing layer and insulation material, you can use slats 2-3 cm thick. If diffuse membranes are used to contain moisture, it is recommended to take care of a tight fit of the insulation.
The material responsible for thermal insulation must fit tightly to the rafters. Otherwise, cold bridges may form, which will not have a favorable effect on the cozy atmosphere in the room. Therefore, the insulation is cut into several large sizes and tightly packed between the rafters. If polystyrene foam is used as insulation, the resulting seams can be sealed with polyurethane foam. To optimally select the amount and thickness of insulation, you should pay attention to the climatic conditions that exist in your region.
Next, you will need to protect the insulation from moisture that forms inside the attic floor space. To do this, you can use vapor barrier materials that are attached to the rafters. Using film in this case, it is laid overlapping, after which all joints are taped for tightness. Only after this are the bars sewn onto the surface, to which the interior decoration of the attic floor will be attached. The resulting gaps between the bars will play the role of ventilation.

In the end, all you have to do is choose the material for the interior decoration. In this case, the most popular are plasterboard sheets or wood cladding products. There are a lot of such options at the moment. Here everyone can choose something individually, giving the attic floor a comfortable and cozy atmosphere.

Currently, create high-quality and comfortable conditions on the attic floor, every owner strives country house or cottage. The process of bringing such premises to the desired result involves a lot of effort. However, every owner correct calculations and carrying out the work, will be able to achieve the desired result. After which, you can observe your work with a touch of pride.