Technical characteristics of the isospan film. Hydro - vapor barrier "Izospan B"

Trademark"IZOSPAN" is presented on the domestic market since 2001, products are produced Russian company HEXA in Tver. Inherent in materials of the Izospan brand specifications, high quality and durability make it possible to supply products for construction from Tver on a par with foreign counterparts of European production. At the same time, Izospan costs less, which provides the domestic brand with constant popularity among professional builders and owners. country houses... We will tell you how Izospan waterproofing differs from vapor barrier, consider the range of products, including high-strength construction films. The technical characteristics characteristic of Izospan D make it possible to use the material as a temporary roof covering.

Izospan is construction films, membranes and tapes designed to protect fibrous insulation and wooden structures from being blown by wind and water, both in liquid and vapor form. Scope of application - multilayer building structures, mainly outdoor. These include pitched roofs, external insulation systems for buildings (ventilated facades). Films and membranes cannot be dispensed with in the construction of a modern frame house... They are also used when constructing wooden interfloor floors. Let's take a closer look at the assortment and characteristics of Izospan, let's talk about the features of the use of materials in the specific conditions of private suburban construction.

In the photo Izospan D, which covered the rafter system. The developer did not have time to lay the roofing in a warm season, but this is not a big deal. Strong polypropylene film will withstand until spring, snow and strong winter winds will not damage it

Multilayer building structures and moisture

To understand how to use Izospan correctly, you will have to understand some issues of construction technologies:

Modern building technologies include various multi-layer structures. They are most justified and popular in low-rise construction. These are frame walls, pitched roofs, ceilings, ventilated facades. The supporting part of the structure - racks, rafters, etc., is often made of wood. The gaps between them are filled with an effective heat insulator. As a rule, fibrous materials are used: mineral wool, ecowool (fluff pulp).

In a multi-layer frame construction, a vapor barrier from the inside and a vapor-permeable membrane from the outside are required.

Such heaters, along with useful properties, also have disadvantages: they are blown through when exposed to the wind and get wet in conditions of high humidity. As a result, their thermal insulation properties are noticeably reduced. The wooden frame is also "afraid" of moisture. It enters porous materials from the air, in the form of water vapor. For most of the year, the humidity inside the house is much higher than outside. Accordingly, from the inside of the house, it is necessary to prevent the penetration of steam into the multi-layer structure. Isolate from steam. Outside the building, the air, as a rule, is less humid, which makes it possible to ventilate and dry the insulation.

If you provide good ventilation, free moisture escape from the insulation and timber frame, their moisture content will be minimal. Accordingly, in a multi-layer structure, vapor-permeable materials should be located on the outside. The above is true for heated homes. For unheated and well-ventilated buildings, vapor permeability does not matter.

Please note: In a multi-layer heat-insulated structure, INSIDE - STEAM PROTECTION, and FROM OUTSIDE - VAPOR PROTECTION. Not the other way around. If, for example, Izospan A and Izospan B are confused, the wall or roof will become waterlogged, which will inevitably damage the building.

From the inside, they are protected from moisture by a vapor barrier film (vapor barrier), and ventilation from the outside is provided by a vapor-permeable membrane (wind protection). Please note that the windproof membrane must not come into contact with the roofing and wall cladding. To remove water vapor, there should be a ventilation gap between them with holes in the lower and upper parts of the walls and roof.

Differences between vapor-permeable membranes and vapor barrier films

On construction sites and forums, you can read, and from the lips of builders and private developers hear such terms as "Izospan waterproofing", "Izospan steam-waterproofing" and "Izospan film". And sellers of building materials will tell you more about the "Izospan superdiffusion membranes".

In the case when the walls are insulated stone building according to the ventilated facade method, vapor barrier is not only not required, but also categorically not allowed. All you need is a vapor-permeable membrane that protects the insulation layer from the street side

It happens that the speakers themselves do not understand the difference between the materials or use the terms incorrectly. Often this confusion leads to the wrong choice of materials, as a result of which the thermal performance of the enclosing structures deteriorates and their service life decreases. To avoid such mistakes, you need to clearly understand how Izospan materials and their analogs differ, as well as what they are used for. In accordance with their purpose, they are divided into two groups: vapor barrier films and vapor-permeable membranes:

Vapor barrier films

Vapor barrier films are impervious to water, steam and wind. That is, they are practically sealed. They are made, as a rule, of polyethylene and more durable polypropylene, to increase strength they can be reinforced. They are also called "Izospan vapor barrier", but this definition is correct only to a certain extent. Indeed, the film is waterproof.

If it is used in the "pie" pitched roof, condensation water or leakage from a leaky coating will not penetrate into the attic. But for underground structures and flat roofs, the standard Izospan B waterproofing film is not the best, it is not strong enough and weather-resistant. True, the characteristics of Izospan B, the cheapest film, are low, there are better materials that can be used for waterproofing concrete floors. But nothing more.

Reflective Izospan sheet is laid as insulation under the heating floor

Application of vapor barrier films:

  • Protection against high humidity of multilayer insulated structures is mounted from the inside, from the side of the room. These are frame walls, pitched roof rafters and wooden floors on the ground floors of buildings without basements.
  • Protection against condensation and possible leaks of rafter structures in an uninsulated ventilated attic. In this case, the vapor barrier is placed on the outside, under the roof covering.

    Please note: The vapor barrier can be placed in the "pie" of the pitched roof from the street side only if the attic is not insulated and well ventilated .

  • In interfloor wooden floors, the Izospan film is placed under and above the insulation. Izospan for floor in wooden house plays the role of not so much a vapor barrier as it prevents the spread of the smallest fibers mineral wool into the premises.

The openings in vapor permeable membranes are large enough to allow water vapor to pass through, but too small for liquid water to enter. Membranes often have a rather complex multilayer structure and during installation it is important not to confuse the orientation: the canvas turns outward with a strictly defined side

Vapor permeable membranes

Vapor-permeable membranes are single or multi-layer nonwoven fabrics with tiny holes. The size of the holes and their number is such that the membrane is not blown by the wind, but when there is a difference in air humidity on the sides of the film, water vapor diffuses towards the side where the air is drier. This allows excess moisture to be removed from the building structures, ventilate them. Liquid water, falling on a vapor-permeable membrane, is not able to penetrate the barrier, the surface tension force interferes. Of course, we are talking about a relatively small amount and pressure of water: individual drops or a little rain. If the membrane is left unprotected by a roofing or wall covering under heavy rain, water will flow through it.

Application of vapor barrier diffusion membranes:

  • Ventilation of multilayer enclosing structures and their protection from liquid water (condensate). Located outside, from the street side. Frame walls, pitched roofs, wooden floors on the ground floors of buildings without basements.
  • The membrane can be used in interfloor wooden floors, but Izospan film is cheaper.

Please note: A vapor-permeable membrane differs from a vapor barrier film in its ability to transmit water vapor. It is important to understand this difference.

It is clear from the diagram general principle application of Izospan materials: outside - vapor-permeable membrane, inside - vapor barrier film

What technical characteristics are important for evaluating the properties of building membranes and films

In order to understand the differences between Izospan materials, and also to be able to compare them with the products of other companies, it is advisable to know which indicators are most significant for assessing the properties of building films. An ordinary consumer does not need to go into details, measurement methods and calculation formulas, but the characteristics that are important for Izospan should be named:

  • Vapor permeability - the ability of a membrane to pass water vapor, provided that the atmospheric pressure on both sides of the membrane is the same, and the partial vapor pressure is different. Characteristic - vapor permeability coefficient, unit of measurement - mg / (m · h · Pa).
  • Resistance to vapor permeation - the ability of the film to retain water vapor, measured in m2 · h · Pa / mg.

Both vapor permeability and resistance to vapor permeability depend on the properties of the material and its thickness. The methods for determining and calculating the values ​​are given in SP 50.13330.2012.

  • Water resistance - the water pressure that the canvas can withstand until the moment of leakage, is measured in millimeters of a water column.
  • Breaking load characterizes the strength of the web. This is the maximum load that a film or membrane can withstand without breaking. Measured in centi-newtons (H x cm).
  • UV stability is the time (months) during which a material can be exposed to ultraviolet radiation outdoors without deterioration.

In the photo Izospan A, the marking of the canvas reflects the purpose of the material, its technical characteristics

Assortment and technical characteristics of Izospan

Depending on the purpose, the materials of the GEXA company are divided into four groups.

Vapor permeable membranes

We already know the purpose of vapor-permeable diffusion membranes: they protect multilayer structures from wind and external moisture outside buildings, ensuring the removal of water vapor from the insulation and the wooden frame. The abbreviation for Hexa membranes contains the letter "A". We repeat once again that building membranes and films are fundamentally different materials... If the seller or potential contractor uses the wrong term "Izospan A film" or an incomplete definition of "Izospan A waterproofing", this is a reason to doubt his qualifications. The manufacturer produces five types of Izospan A vapor-permeable membranes, the technical characteristics of which differ. There are differences in usage:

  • ISOSPAN A is a single-layer membrane, the simplest and most inexpensive. The low water resistance of Izospan A, the vapor permeability characteristics do not allow the material to be used in pitched roofs, it is used only in vertical wall structures, including ventilated facades.

  • IZOSPAN A with flame retardants. The technical characteristics of Izospan As OZD are almost identical to the A grade, but the canvas has fire-fighting properties. It is recommended to use it for external insulation of wooden buildings.

  • IZOSPAN AM is a multilayer membrane with increased water resistance, which makes it possible not only to use it in the "pie" pitched roof with high condensation, but also place directly on the insulation without a gap. This simplifies the roof structure and saves money.

  • IZOSPAN AS, whose technical characteristics in terms of steam permeability coincide with the properties of the AM brand, are somewhat stronger, which is important for large roofs with a significant rafter pitch.

  • IZOSPAN AQ proff is an extra strong membrane with high vapor transmission and water resistance. Recommended for all types of multi-layer ventilated walls and roofs of critical facilities. The most effective, durable and expensive membrane.

Vapor barrier films

Construction films impermeable to water, steam and wind. They are installed from the inside of multilayer walls and roofs of heated buildings, they are also used to protect the walls and roofs of unheated buildings from the weather from the outside.

  • IZOSPAN B is the least durable, but the cheapest vapor barrier. It is not worth counting on the technical characteristics of Izospan B to be high. Izospan B, whose characteristics in terms of strength and durability leave much to be desired, is perfect for utility structures, interfloor ceilings. For a responsible object, a house in which you are going to live for a long time, it is worth using a more reliable and expensive film. For example, Izospan S, the technical characteristics of which are higher.

  • IZOSPAN C is a film that can be used not only as a vapor barrier, but also as a waterproofing when installing floors on the ground and on a concrete base.

  • IZOSPAN D is a two-layer extra strong vapor barrier film. Technical characteristics of Izospan D allow it to withstand the snow load, the canvas can be used as a temporary covering for a pitched roof. But no more than a period of UV stability, which is 3 months in summer and 4 months in winter.

  • IZOSPAN RS is reinforced with glass threads, which increase its tensile strength. Like grade "C", it can be used for flooring on the ground and even for waterproofing flat roofs. True, not as a coating, but only on the bottom of a multi-layer "cake" to protect the insulation from water vapor.

  • IZOSPAN RM is a three-layer reinforced vapor barrier film designed for roofs and floors.

Reflective vapor barrier

Reflective insulation Izospan is a film, the technical characteristics of which allow us to say that the material combines four functions: insulation from steam, water, wind and thermal protection of building structures. It cannot serve as a full-fledged insulation, but the foil layer reflecting infrared rays inside the premises reduces the heat loss of the building. Varieties:

  • IZOSPAN FB is made of kraft paper and metallized lavsan, intended for baths and saunas.

  • IZOSPAN FS is made of polypropylene and has a metallized coating. It is used in multi-layer constructions and underfloor heating screeds.

  • ISOSPAN FD is similar to the FS brand, but has increased strength.

  • IZOSPAN FX is made of foamed polyethylene, coated with a metallized lavsan layer. Izospan FX insulation, the technical characteristics of which are quite high in terms of thermal insulation, are not very strong. Therefore, it is more rational to use it as a substrate for underfloor heating.

Connecting tapes

Tapes are construction tape on special bases, designed for gluing together different types Izospan canvases, sealing films and membranes. Separately, we will highlight SUL - a self-adhesive sealing tape. It has a different function. SUL is glued to the rafters over the already mounted membrane. The tape is designed to prevent moisture penetration into the wood through fasteners(nails, screws). Recommended for use when the roof slope is less than 22º.

We have only in general terms mentioned the range of insulating materials of the company GEXA, you can find out more about their use on the manufacturer's website.

You can determine how to properly use Izospan materials by carefully studying technical materials on the manufacturer's website. Under the roof, outside, the builders install the Izospan AM membrane, and from the inside, from the attic side - Izospan D, the photo illustrates this well

In conclusion, we will say that we have told only a small fraction of what you need to know to successfully build your own home using multi-layer building structures. This task requires certain knowledge from the performers and careful observance of the technologies prescribed by building codes and recommended by manufacturers. If you are not going to deeply study this issue on your own and do the work with your own hands, entrust the design and construction of your own house only to trusted specialists.

When building an energy-intensive home, the main task is to provide effective thermal insulation. There are many types of insulation materials available to do this. But sometimes it alone is not enough to successfully solve the task. It can retain heat well inside the house in stable conditions - with moderate humidity. But when the weather outside changes - the temperature drops and the humidity rises, the effectiveness of thermal insulation decreases in this place, since without special protection, its humidity also increases. Therefore, in order to achieve this goal, other materials are required to protect the thermal insulation and various structures of the room from the negative effects of moisture. One of these materials is Izospan.

What is Izospan - what is it for?

Izospan is widely known today in the Russian building materials market, it is a domestic brand manufactured in the form of a membrane film, and has a wide range of applications. It is an excellent means of protecting against moisture that affects both outside and inside the room.


Izospan characteristics

Izospan is an effective protective agent against moisture of any type: water, steam, condensation, etc. It can be different types, depending on this, some types are used to protect the insulation in the roof, others are used to protect the structure of the cold roof. In addition to all this, it serves as a good waterproofing for walls, in interfloor ceilings, on basements - in concrete and other moisture-absorbing floors.

There are several varieties of it, each of which has its own functional affiliation.


What is Izospan

Isospan types and technical characteristics

Izospan can be divided into four large groups- A, B, C, D, each type has its own design features, which determines their functional purpose

Izospan category A

The design of this category has effective moisture protection properties, as well as allows for protection from the wind. The main task is to protect the thermal insulation layer of the house from the outside. The structure of the membrane is as follows - the surface is smooth and does not allow moisture to pass through. The inner side is porous, which makes it possible to effectively eliminate the accumulated moisture from the insulation side. The material is mounted on the outside of the insulation layer, under roofing material or if it is a wall, then under the facing material.

When used on a roof, according to technical recommendations, its angle of inclination should be at least 35 °. It should also be noted that it should be laid in the absence of precipitation.

Technical characteristics of Izospan A

  • Composition: Propylene 100%
    • : 190/139 N / 5cm
  • Water vapor permeability, not less: 3500 g / m2 / day
  • Water resistance not less: 330 mm water column,
  • Application temperature: -60 to + 80 0 С
  • Dimensions (edit): Width 1.4 -1.6 m,
  • Square: 35; 70 sq.m


Izospan A - photo

Izospan category B

This type has a two-layer construction, upper layer with a smooth surface, the bottom without roughness - it retains condensate drops and promotes their rapid evaporation.

Izospan B protects internal building elements from water vapor emanating from the inside of the room. It is laid on the inside of the room on the insulation, suitable for both walls and roofs, can be used in ceilings.

Specifications Izospan B

  • Composition: Propylene 100%
    • : 130/107 N / 5cm
  • Resistance to vapor permeation m2 hour Pa / mg, not less: 7.0
  • Water resistance not less: 1000 mm water column,
  • Application temperature: -60 to + 80 0С
  • Dimensions (edit): Width 1.4 -1.6 m,
  • Square: 35; 70 sq.m


Izospan B photo

Category C

This type allows you to effectively protect the internal structures of buildings from steam, condensate. The structure is similar to the types described above, excellent for steam and waterproofing of any type of roof, including flat. They are used to protect wooden structures in cold-type roofs (also suitable for insulated roofs).

Izospan S is also used in cement-concrete screeds in basement ceilings and in the foundations of any wet rooms.

Any building under construction now, or already built, industrial or residential, is literally surrounded by heat-insulating materials from all sides. They create comfort in the room, save heat, reduce the influence of atmospheric phenomena such as rain, snow, wind, etc.

But, as it turned out, this reliable thermal insulation layer, which protects buildings, itself requires protection from both moisture and wind. And it serves as such a protection modern material, one hundred percent polypropylene, which is called isospan A, B, C, D, the instructions for use for which we will consider.

Creating a barrier for an existing barrier is the main purpose of Isospan. Let's look at the general technical characteristics of the new Izospan heat insulator, see photos and videos, talk about its types and installation methods different types material, and which side to put it to the insulation.

Izospan: technical characteristics

- highest strength
- good elasticity
- environmental safety (isospan does not emit harmful substances)
- ability to withstand high pressure

To the above, it can also be added that some types of isospan have fire-fighting properties if special refractory particles were added to them at the production stage. All types of isospan are well resistant to ultraviolet rays and withstand temperatures the environment from -60 to + 80 degrees.

Taking into account the fact that isospan was developed in several forms, let us touch on in detail the characteristics of the main modifications of the insulator: these are types A, B, C and D. This is necessary to know if you intend to use isospan in the construction or insulation of buildings.

Roof covering with isospan


Izospan A- This is a kind of membrane that protects the structure from moisture (waterproofing), and helps to remove water vapor from the insulation. It is used to protect walls and facades of premises for any purpose. With its protective properties, it extends the service life of the insulation. It can be safely called wind and waterproofing protection for your home.

Material tensile strength: 190/140 mm (long / cross)
UV stability: 3-4 months
Water resistance: 300 mm
Water vapor permeability: not less than 2000

Izospan type A reliably provides thermal insulation of the insulation and has:

- good resistance to external mechanical stress
- resistance to harmful substances (chemistry, bacteria)

When installing isospan, the following question often arises: which side to the insulation to lay it?

Izospan A is mounted from the outside of the insulation. When installed on an insulated roof, it is cut into wide strips and overlapped so that the smooth surface remains outside.

Installation starts from the bottom of the roof. When working with Isospan A, do not allow it to come into contact with itself, since the waterproofing properties of Isospan are greatly reduced with such direct contact.

Make sure that during the installation of this type of isospan there are no different kinds of swelling or sagging, because in gusts of wind, it will create popping, banging and other unpleasant noises in the room. Isospan A is fastened with rails with nails. A free space of 5 cm is left between the sides of the insulator. We are watching a video about izospan: which side to lay on the insulation.

If Isospan A is used as a wind and hydro-barrier for insulation, then isospan B you can call it a vapor barrier. Any insulation, even the most modern, is saturated with water vapor over time. The task of Isospan B is to create a barrier to these vapors inside the building.

The material has 2 layers and is used to preserve the surface:

- sloped roof
— interior walls
- frame walls
- attic, basement floors

Isospan B properties:

- breaking load prod. / Trans. N / 5 cm not less than 130/107
- vapor permeability about 7
- water resistance 1000 mm water column

Since isospan B consists of two layers, each side has its own functions. Its smooth part provides the adhesion strength of the insulator to the main insulation layer. The rough or fluffy side helps to retain moisture particles and drain condensation.

Izospan B is laid on the inside of the heat-insulating layer when using a stapler. Installation is carried out in the direction from bottom to top, overlapping, while ensuring a tight contact of materials. On the side with a fleecy surface, create a free space of at least 50 mm.

Izospan B


Izospan S has very similar characteristics to isospan B, they are similar in structure, they also have a structure of 2 layers, but isospan C is more durable, heavy-duty, used to protect the floor, interfloor ceilings, cold roofs. The extra strength and special reliability of this type also determine its price, which is higher than the price of Isospane V.

Isospan C properties:

- made of 100% polypropylene
- breaking load 197/119 prod. / Trans. N / 5cm
- resistance to vapor permeation - 7 m2hPa / mh
- water resistance - 1000 mm water column

Isospan C use:

1. Water and vapor barrier of non-insulated sloped roof
2. Flat roof
3. Water and vapor barrier of frame walls
4. Vapor barrier wooden floors horizontal type
5. Steam and moisture insulation of concrete floor

On pitched roof surfaces, it is installed horizontally, with an overlap (15 cm), the work takes place from the bottom up. A special tape is applied to the formed joints. Fasteners are made using rails.

When working with ceilings, Isospan C is placed on top, overlapping, leaving a small gap of 50 mm from the film, heat insulator and floor. When working with concrete floors, Isospan of this type is mounted directly on concrete surface, and a screed is carried out on top.

Roof waterproofing with isospan


Izospan D is a modern high-strength vapor and waterproofing material. This type of isospan can be called a polypropylene woven fabric having a two-layer structure.

A feature of Isospan D is that, in comparison with other types of polypropylene materials, it has the ability to withstand very significant mechanical influences during installation, and is also able to withstand a large snow load.

Scope of isospan D

It is used in construction as a waterproofing and vapor barrier for under-roofing, in non-insulated pitched roofs, as well as for protection various designs made of wood. Serves as a reliable barrier on the way of under-roof condensate, as well as atmospheric phenomena in the form of snow, wind, especially in those places where the roof is not laid tightly enough.

Izospan D is used to form a temporary coating layer for waterproofing the roof and walls of buildings (up to 4 months). Also, this type of isospan has proven itself well as a waterproofing layer when working with floors on a concrete and earthen base, and when insulating basement floors in buildings with high humidity.

Used for insulation:

— flat roof
- floors on a concrete base
- basement floors
- sloped roofs

Izospan D


Physical and mechanical properties of Isospan D:

- breaking load prod. / Trans. N / 5cm: 1068/890
- resistance to vapor permeability m2hPa / mh: not less than 7
- water resistance: 1000 mm water column
- UV resistance: 3-4 months.

Izospan D finds its application in works, in order to preserve internal parts houses and insulation from the influence of water vapor accumulating inside the room. It should be noted that the installation of Isospan D, like other types of Isospan, is easy enough, which in itself provides a good, constantly growing demand for this modern insulating material.

When laying Isospan D on an uninsulated roof of an inclined shape, the material is cut directly on the rafters. It does not matter which side of the insulator is mounted to the surface. Isospan D canvases are laid horizontally, with an overlap.

Work starts at the bottom of the roof and continues upward. The joints formed during the laying of the material are connected with a special adhesive tape. The stretched, ready-to-use material is fastened vertically to the rafters with wooden slats and studs.

As you can see, at very good characteristics, modern insulating material isospan it is quite simple to use and does not require any special skills and knowledge when installing it. But the functions that Izospan will undertake will ensure the reliability and durability of the operation of your entire thermal insulation system. Watching the video.

Thermal insulation of a building and its protection from atmospheric moisture are the basis of comfort and a guarantee of the durability of structures. Construction works aimed at solving such problems, it is impossible to perform well without the use of special steam and waterproofing materials.

For high-quality protection of structures from steam and moisture, brand names should be preferred when purchasing.

Vapor barrier Izospan, for example, is represented by a wide range of products, each of which is optimally suited for a particular type of work. This allows not only to qualitatively protect the insulation from sticking and weathering, but also to save on insulation work. Since we are talking about such a popular insulating material as Izospan, we will dwell on it in more detail.

The range of the brand currently includes 14 positions of roll insulation.

The first group is represented by vapor-permeable membranes, which differ in density, strength and vapor permeability. Their resistance to solar ultraviolet (UF-stability) is the same and ranges from 3 to 4 months. This parameter must be taken into account, since it shows how long such a membrane can stand under the open sun without losing quality.

Membrane Izospan A designed to protect insulation and supporting structures from under-roof condensation, atmospheric moisture and wind. Reviews of this type of isolation are mostly positive. This material is excellent for steam and waterproofing of all types of sloped roofs. Install it on the outside of the insulation.

Izospan AS - a three-layer polypropylene membrane designed to insulate roofing, wall structures and insulation from external moisture and water vapor coming from inside the room.

Izospan AM - universal vapor-permeable two-layer membrane. It is used to protect insulation and roofing elements from weathering and condensation.

Izospan A with flame retardants (OZD) eliminates the risk of fires in structures during welding, waterproofing walls and basements using a blowtorch.

What is the difference between these types of insulation? The strongest and most durable is the AS brand. Izospan A passes water vapor best of all (3000 g / m2 / day). For Izospan AS and AD, this figure is 1000 and 1550 g / m2 / day, respectively.

Despite the lower vapor permeability, membranes of the AS and AD brands can be installed directly on the insulation. Izospan A for high-quality steam removal requires an air gap, which is made by stuffing a counter-rail onto the rafters. Therefore, the labor intensity and consumption of materials when installing this insulation will be higher.

The next class of insulation of this brand is characterized by a lower price and a wide range of applications - Izospan polypropylene vapor barrier films B, C, D and DM.

Isospan B film optimal as a vapor barrier that reliably protects thermal insulation and structures in a pitched warm roof, interfloor ceilings, light frame walls, attic and basement ceilings.

Izospan has B, C, D and DM the structure of the canvas is two-layer. One side of these films is made smooth, and the other - rough. Roughness in this case is necessary for better retention of water condensate and faster evaporation.

Which side to put isospan on is easy to understand even for a beginner... Water vapor, passing through this material, condenses on its outside... Therefore, Izospan grades B, C, D and DM are always laid with the rough side out.

The instruction for use of Izospan S indicates that it can be laid not only in the roof (warm and cold), but also used as a waterproofing for all types of bases (earthen, sandy, crushed stone). This material has proven itself well in the construction of concrete floors in rooms with high humidity.

Izospan grades D and DM are distinguished by increased resistance to solar radiation and high tensile strength (a 5 cm wide strip of this material can withstand a load of up to 106 kg). Therefore, it can be used for temporary roofing without fear of rupture of the canvas due to the snow load. For grades B and C, the strength is significantly lower - 13.0 and 19.7 kg / 5 cm, respectively.

Relatively recently Izospan RS and RM films have appeared on sale reinforced with polypropylene mesh. Their breaking strength is 41.3 and 39.9 kg / 5 cm, respectively.

The next group of Izospan materials is represented by FS, FD, FB and FX insulating films ... This is very interesting materials, since they have implemented a progressive method of thermal insulation - reflection of infrared radiation.

Such films not only reliably protect walls and insulation from condensation, wind and precipitation, but also make a significant contribution to increasing the level of energy saving.

These materials absolutely do not allow water vapor to pass through, therefore, they should be used only in rooms where a forced mechanical ventilation system works. Another area of ​​application is reflective underfloor heating and wall screens behind radiators.

Different brands of Izospan heat-reflecting insulation differ from each other only in mechanical strength and type of material. Izospan FD has the highest strength (80 kg / 5 cm). It is followed by the FB, FS and FX brands (35, 30, and 17.6 kg / 5 cm).

Izospan FS and FD are made of double polypropylene film. One side of it is metallized and plays the role of a reflective screen.

The FX brand is made of 2 to 5 mm thick foamed polyethylene covered with a metallized film. The basis of Izospan FB, which is often called bath foil, is kraft paper laminated on one side with metallized lavsan.

The reflection coefficient of thermal infrared radiation for these types of insulation is the same and is 90%.

Installation of Izospan does not apply to complex types of work... Laying of panels of waterproofing can be carried out vertically or horizontally, depending on the location of the lathing frame for internal or external wall cladding.

Installation diagram of membranes and films Izospan

  • 1 - roofing material;
  • 2 - lathing;
  • 3 - Izospan membrane (A, AS or AD)
  • 4 - lathing;
  • 5 - rafter leg;
  • 6 - film Izospan D, Izospan B or Izospan C;
  • 7 - insulation;
  • 8 - inner lathing;
  • 9 - filing (drywall, lining).

Ventilated facade insulation diagram

  • 1 - facade decoration;
  • 2 - supporting structure;
  • 3 - membrane Izospan A;
  • 4 - thermal insulation;
  • 5 - wall

Insulation of basement and interfloor overlap on wooden joists

  • 1 - finishing floor;
  • 2 - black floor;
  • 3 - distance rail;
  • 4 - isospan B;
  • 5 - lags;
  • 6 - hemming board;
  • 7 - isospan C;
  • 8 - thermal insulation;
  • 9 - fixing rail;

The Izospan insulation is fixed with a chiseled fastener or with the help of lathing bars. When installing panels, it is necessary to maintain an overlap of at least 10 cm. All joints should be carefully glued for high-quality sealing. For this, the manufacturer completes its insulation with Izospan FL metallized tape.

You will understand how to lay Izospan at the points of abutment to the walls and other structures of the building by watching the videos of the installation companies that they post on the Internet. On our own behalf, we add that in this work it is especially important to carefully fix all the junction areas and reliably seal them using a special Izospan SL butyl rubber tape.

At the end of our review, we present an indicative list of prices for Izospan insulation.

Useful video

The device of moisture and vapor barrier is a very important stage of construction. One of the best materials used for this purpose is isospan. It belongs to the category of relatively new products used in the protection of structures. The manufacturer provides a wide range of insulating films that differ in purpose.

You will learn everything about the range of membrane films labeled as isospan A, B, C, D from our article. We have described in detail the popular insulating materials, given their technical characteristics. Independent DIYers will find installation manuals and useful tips.

For the most part, isospan is produced in the form of a membrane or film. Both versions have a vapor barrier function. There are types that are 100% waterproof and unilaterally permeable to moisture. If we consider the types of this material separately, then each is intended for separate tasks.

The term isospan hides four broad groups - A, B, C, D. They are distinguished by individual design features.

Isospan is used in the device, installation of cold roofs, the construction of baths, as an insulator for enclosing structures. The material is especially effective as protection of insulation systems and wooden elements from putrefactive processes, and metal ones from corrosion.

There is isospan used inside buildings, and other varieties are intended for outdoor use. Isospan is also available universal application... In any case, its use makes it possible to significantly prolong the operation time of the insulation, which, under the influence of moisture, quickly loses its properties.

There are three main groups of isospan: moisture- and windproof, steam- and moisture-proof, vapor-proof. Materials included in the second group are used for interior finishing work

Vapor-proof isospan is used for both indoor and outdoor work. According to the functionality of the material, it is divided into classes.

Insulation material group A

The material marked with the letter "A" belongs to the first group. It is characterized by high density, therefore, it is irreplaceable when insulating attics, walls, roofs. Fungi and mold do not develop on it.

This diffusion membrane retains water, but steam passes through it unhindered. Polypropylene is used for manufacturing. It strengthens and protects thermal insulation from the influence of outdoor atmospheric moisture or cold air from the side of a room that is not heated.


Izospan A is an excellent wind barrier for ventilated facades. It neutralizes the consequences caused by the onslaught of side winds that favor the escape of heated air from the heat-insulating layer.

In order for Izospan A to fully reveal its capabilities, it is necessary to follow the technology exactly during installation. Since air jets pass through it only unilaterally, in no case should the sides be confused. Otherwise, the insulating layer will get wet due to the accumulation of moisture in it.

Isospan A is produced in rolls with a width of 1.6 m. The area of ​​the material in a reel is 35.7 m². Optimum temperature limits for operation are -60 - 80⁰. For three, or even four months, the membrane can be influenced by ultraviolet radiation without loss of characteristics. Subsequently, these aggressive rays will gradually reduce the UV stability of the material.

Izospan marked with the letter A may contain fire retardant additives. Then, to all its characteristics, one more is added - protection against fire. This brand belongs to the G1 flammability group, and according to the flame propagation rate - to the RP1 group.

The material can withstand quite high breaking forces - from 125 longitudinal and from 95 N / 5 cm transverse. This is facilitated by special additives that strengthen the structure of the material.

The vapor permeability of the material is at least 3500 g / m² day. Water resistance parameter - 330 - mm. water Art. Based on these characteristics, it is advisable to use Isospan A when installing ventilated facades, frame enclosing structures, roofs with double lathing and slopes at an angle of 35⁰.


The 3-layer AS membrane well insulates both wall and roof structures from street moisture and steam. The presence of such a barrier guarantees the safety of the insulation

In contrast to the A-group membrane, the AM film has a two-layer structure. She also found application to protect insulation, roofing elements from condensation, weathering.

These types of insulation have a number of differences:

  1. AS- the most durable, in addition, stands out for a rather significant service life, but the steam transmission rate is only 1000 g / m² per day.
  2. A - best view by steam capacity.
  3. AD- a strong membrane with a vapor permeability of 1500 g / m² per day.

There are differences in terms of installation. If grade A is selected, an air gap is required, otherwise the steam will be discharged ineffectively. Membranes AS, AD are mounted directly on the insulation.

The second group marked B

This vapor barrier has a slightly lower price.

The technical parameters of Isospan B are as follows:

  • composition - polypropylene;
  • application temperatures - -60 - 80⁰;
  • water resistance - 1000 mm of water. With t. Minimum;
  • UV resistance - 3 - 4 months;
  • minimum vapor permeability - 7 gr. per m² per day;
  • The structure is two-layer.

Used as a subroofing film in frame enclosing structures, in interior partitions... On the one hand, it is smooth, the opposite side is rough, it is on it that moisture is retained and it evaporates.

With its help, the building is insured against penetration inside, walls, systems in a private house.


Isospan grade B is laid so that the rough side is on top. It is a high-quality steam and waterproofing for rooms with traditionally high humidity - bathrooms, toilets, showers, basements

The price of this brand is the most democratic. Unlike grade A, this material is not attached from the top of the insulation, but from its bottom side. Do it from the bottom up, then overlap. For better capture of water vapor, a 5 cm gap above the rough layer is required.

Features of the material of group C

With regard to resistance to vapor permeation, water resistance, UV stability, this type of insulation does not differ from the previous material. Isospan brand C has the same temperature range: (-60) - (80⁰). The difference in breaking load, here it is greater - longitudinal minimum 197, transverse - 119 N / 5 cm.

The two-layer film is particularly durable. Polymer membranes of group C are used for waterproofing and vapor barrier for protection, attics, roofs with a slope of maximum 35⁰.

They are used as a waterproofing substrate for metal tiles, as it perfectly protects the rafter system from rain and melt water. In addition, it is a good waterproofing for different types of substrates. The material is also used in the case of concrete floors in places of high humidity.

Description of brand D products

A distinctive feature of Isospan D is its good UV resistance. Tensile strength is also high - longitudinal breaking load - not less than 1068 N / 5 cm, 890 - transverse.

Due to its high strength, grade D polypropylene fabric can withstand considerable mechanical forces during installation and operation, including the weight of snow. For this reason, it is quite suitable as a non-permanent roof that functions normally for about 4 months.

The material also proved to be good in the role of under-roof waterproofing in cold roofs. It saves wooden elements from the destructive influence of moisture penetrating from the outside, as well as wind, snow, which may end up there through leaks in the roof. It is also an effective waterproofing layer in basement ceilings.

Installation instructions for isospan

Steam, moisture and wind protection of a building is a complex event. Using glassine or plastic wrap is ineffective. Izospan is specially designed for this purpose and its high qualities have been tested in practice.

For installation, in addition to Isospan itself, a stock of tools and fasteners is required:

  • special scissors;
  • self-tapping screws;
  • construction stapler;
  • connecting tape;
  • metal profile or wooden slats.

It should be remembered that the membrane is attached to the walls both from the inside of the room and from the outside, and on the roof - only from the inside. The peculiarities of a particular type of isospan are reflected in the instructions for use of the material.

Mounting the diaphragm of group A

The best use of this thermal insulation, waterproofing, windproof membrane is to protect the frame wall of low-rise buildings from moisture and wind. It is mounted on the outside of the insulation layer under the outer finishing of the building.


The outer side of Isospan A does not allow moisture and wind to affect the state of the insulation. Internal - prevents the formation of condensation, because has the property of removing steam

Isospan A is laid in accordance with its technical characteristics on top of the insulation along a special frame.

The technology is simple and does not require special qualifications:

  1. The roll is unrolled and cut into panels of the required size.
  2. Sections of the membrane are alternately placed on the frame horizontally with an overlap with the straight side outward, starting from the bottom, and moving upward.
  3. Attach the protection to the frame with an overlap using a construction stapler or other method. The minimum overlap both horizontally and vertically is 100 mm.
  4. The material is additionally strengthened. To do this, the stretched panels are pinned to the rafters with a construction stapler.
  5. To seal the overlap, the joints of the panels are fastened with a 2-sided Isospan KL tape.
  6. Self-adhesive tape is laid in the area of ​​attachment.
  7. On top of the isospan layer, wooden counter-rails are attached vertically to the frame. They are pre-treated with an antiseptic. The size of the slats is 40 x 50 mm. They act as a supporting structure for external cladding - in the form of lining, siding, etc.

A prerequisite is a ventilation gap equal to the thickness of the counter batten between the isospan layer and the outer skin. The bottom edge of the membrane is positioned so as to divert the dripping moisture into the drain of the building's basement.

Laying the film Am and As in the insulated pitched roof


The material protects the supporting structure and insulation from condensation collecting under the roof, as well as from snow, wind, moisture that enter through loose laying of the coating

The membrane is laid without a ventilation gap, so there is no need to arrange an additional crate between the insulation layer and isospan. Fix it taut.

The sequence of operations is as follows:

  1. The roll is rolled out and cut directly on top of the insulation.
  2. The panels are laid out horizontally, turning the white side to the insulation. Start of installation - the lower part of the roof. The segments overlap horizontally and vertically by at least 15 cm.
  3. Strengthen the membrane along the rafters with a stapler.
  4. The joints are fastened with solid 2-sided tape isospan KL.
  5. The traces of fastening with nails or self-tapping screws are closed - they are glued with a self-adhesive strip along rafter legs and other elements. This is especially true for roofs with a slight slope - up to 22⁰.
  6. Wooden antiseptic slats 4 x 5 cm are vertically fastened on top of the tape along the rafters.
  7. The crate is mounted on the counter-rails. Based on the type of roof, it can also be a continuous flooring.

To eliminate the under-roof condensation between the front side of the film and the roof covering, a condensation gap is arranged using slats about 50 mm thick.


For free air movement in the space under the roof, the bottom of the roof and the ridge area are supplemented with ventilation holes. Moisture from the membrane surface flows into the drain along the lower edge of the membrane

When installing isospan along the crate, a slight sagging is allowed. A membrane without insulation is practically useless.

Application of insulating material B

This type of membrane perfectly performs the function of a vapor barrier, which protects the insulation layer from water vapor rushing upward from the side of the room, and also protects the space of the rooms from the ingress of insulation particles into them.

Mount it from the side of the insulation, directed inside the room. Installation is carried out using a construction stapler on rafters or rough sheathing. Sometimes galvanized nails are used for this purpose. That's right, when the flat side is closely adjacent to the insulation.

Work starts from the bottom. The vertical and horizontal overlap is the same as when installing other types of isospan - from 150 to 200 mm.

As in the case of Isospan Am, the joints are glued with Izospan KL, SL strapping tape. The contact points of the material with structures of any material are sealed by using a one-sided adhesive tape isospan ML proff.


If the room is finished with clapboard, the vapor barrier is fixed using wooden slats impregnated with a septic tank 4 x 5 cm.For plasterboard sheathing - galvanized profiles

To wooden base interior decoration fixed with a ventilation gap of approx. 40 mm. In the case of using Isospan as a vapor barrier for a frame wall, it is fixed from the inside of the insulation to the loaded frame parts or to the rough sheathing.

A stapler is used as a tool, although the use of galvanized nails is also possible. It is laid on the insulation with the flat side to it. When decorating walls with plasterboard, galvanized profiles are used, clapboard - wooden counter-rails.

Izospan as a vapor barrier attic floor placed in between finishing material ceiling - rough ceiling. Turn to the last one smooth surface... In this case, the ventilation gap is also mandatory.

The vapor-permeable membrane of grade B is also a good hydro-vapor barrier for interfloor floors. Mount between ceiling decoration and a draft system. The rough side is turned down. Fastened over the beams with an overlap.

Between the insulation layer and the final vapor barrier layer, between the finishing floor and the vapor barrier layer, between the finishing ceiling material and the lower layer of Isospan B, arrange a ventilation gap.

The bottom of the basement floor must be protected with a layer of steam and waterproofing. This must be done so that moisture does not penetrate from the ground to the insulation and other structural elements. The recommended type of isospan for this purpose is D.

The best option for using brand D

Isospan type D for a cold pitched roof is an excellent hydro-vapor barrier. By using it, they protect the elements and structures of the attic room, made of wood, from under-roof condensation, snow, wind, atmospheric moisture.

Starting the installation of a protective barrier for a cold pitched roof, Isospan D is spread, cut out. All this is done right on the roof rafters. The advantage of the material is that it does not matter which side to attach this isospan, which is very convenient.

Horizontal sections are overlapped, traditionally starting from the bottom of the roof structure.

Conclusions and useful video on the topic

Video # 1. How to properly lay the vapor barrier in the house:

Video # 2. The sequence of work when arranging the interfloor and ceiling overlap:

Video # 3. Demonstration of the process of laying a vapor barrier film B to protect the roofing cake from household steam:

Laying hydro and vapor barriers is an extremely simple process, but the protection they provide to structures is very effective. Protection against atmospheric water and household vapors - a guarantee of a long service life of materials used in construction.

The key point when choosing a certain type of protection is the specific place and circumstances of its installation. In this regard, when purchasing material, you need to carefully study the permissible options for its use.

Tell us about how you used Izospan insulating films in the arrangement of the attic at your own dacha or in country house... Share useful information on the topic of an article that may be useful to site visitors. Please leave comments, post photos, ask questions in the block below.

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