Optima vapor barrier which side. Proper vapor barrier with your own hands

The roof structure is a complex system. It consists of several layers dissimilar materials, each of which performs its own unique function.

To provide comprehensive protection buildings from influence environment necessary quality performance all installation work, as well as the correct choice of base and insulating materials. This whole process is briefly called.

Standard Composition roofing cake includes:

Inner finishing layer;
The design of the crate;
Counter-breech;
(does not apply to a cold attic);
(about);
ventilation shafts or gaps;
Roof covering.

Why do you need a roof vapor barrier? Vapor barrier layer protects the roof from the penetration of water vapor into the thermal insulation. The fact is that insulating materials for the most part have porous structure, since the air contained in them performs the function heat insulator. When in contact with a colder environment, the vapor turns into condensate, which lingers in voids.

This can lead to a violation of the functionality of the heat-insulating material, as well as the occurrence of decomposition and decay processes in the summer. In winter, freezing water expands, thereby breaking bonds between cellular elements.

The main characteristic of a vapor barrier material is vapor permeability, depending on the density of the material. The values of this indicator can be found in the passport of the packaged building material.

Release form of vapor barrier films - roll. Vapor barrier can be made from various materials. Some of them have additional positive properties that increase operational efficiency. interior spaces building. Installing a vapor barrier on the roof is not as difficult as it seems at first glance, but it requires a careful approach and accuracy.

Types of vapor barrier

Single layer polyethylene films

Manufactured from low density polyethylene elevated degree steam penetration. This material often has defects associated with the ingress of foreign particles during manufacture. The cheapest type of insulating material.

Reinforced polyethylene films

Compared to single-layer polyethylene, reinforced vapor barrier has little greater thickness, as it includes a reinforcing frame. It is made up of polymer twisted threads located in mutually perpendicular directions. The mesh is fastened to the polyethylene base by warm pressing.

This technique does not affect the waterproofing and mechanical properties material, but reduce the degree of vapor barrier.

Anti-condensation film

Made from two layers: smooth and hairy. The smooth layer is attached to the surface to be insulated. The fleecy layer is created from cellulose fibers. Steam, falling on such a surface, clings to the fibrous structure, thereby preventing moisture from dripping onto the underlying structures. pitched roofs. Excess water is removed together with air through the ventilated space.

Polymers with a foil layer

They are made of penofol or foamed polypropylene, covered with a thin layer of metal. Thanks to the reflective properties metal surfaces this vapor barrier provides additional function protection against heat loss.

Membranes (film for roof vapor barrier)

Membrane vapor barrier materials are divided into five main classes:

Type A. It has increased resistance to moisture and wind. Fits between roofing and thermal insulation layer. Manufacturing technology - spunbond. Such a vapor barrier does not allow moisture to flow through the cracks. roofing material, as well as from the resulting condensate. The absence of a laminating layer allows the use of such membranes in roof structures with a slope over 35 degrees. To remove excess moisture, it is necessary to arrange ventilation holes from double crate located between the membrane and the insulation.
Type AM. Unlike Type A has a multilayer structure. It is located between the insulation and the roof, to provide adequate protection from negative atmospheric influences. The most common is a three-layer construction, consisting of two layers of spunbond with a diffuse film located between them. It acts as a waterproofing, as it allows steam to pass through, but retains water. Laying is carried out directly on the heat-insulating layer, which reduces labor costs for the device of the ventilation gap.
Type B. Double layer material. It consists of a layer of vapor barrier film and spunbond. It is used to protect the insulation from the internal vapors of the building. Applies only in insulated roof structures.
Type C. It is made similarly to type B membranes. It has a stronger and thicker spunbond layer, which provides better protection of the insulation from moisture. Used in insulated and non-insulated, pitched and flat roofs.
Type D. Consists of polypropylene fabric, protected on one side with a laminating polymer coated. The structure of the material allows it withstand significant mechanical stress. This causes it to be laid between the insulation and the attic floor screed, as well as in non-insulated roof structures.

Which side is the vapor barrier for the roof?

The principle of installation of vapor barrier materials depends on which side is the layer responsible for the repulsion of water vapor:

We figured out which side to lay the vapor barrier on the roof, now we will analyze in detail how to properly lay the vapor barrier on the roof.

Vapor barrier for the roof: how to properly install using special technology

Laying the vapor barrier on the roof is carried out as follows:

Laying can be done vertically and horizontally. In the second option, the installation of the roof vapor barrier is carried out starting from ridge part roofs. Each subsequent strip is superimposed on the previous layer. with an overlap, the value of which should not exceed 10 cm.

CAREFULLY!

When joining elements, a mandatory seam sealing, which provides optimal protection against moisture ingress into the gap between them. Most often, gluing is done with one- or two-sided adhesive tape or adhesive tape. In roofs with a slope of up to 3o degrees, additional fixation with wooden planks.

To wooden truss elements the vapor barrier is fixed with galvanized nails or a construction stapler.
When installing films and membranes near roof hatches, you need to use a special vapor barrier apron which is included as standard.
At the joints with ventilation pipes, film and membrane structures are wrapped down, wrapped around the pipe and tightly fixed with construction tape.
After laying the vapor barrier layer, it is necessary to nail wooden blocks. The rules for laying vapor barrier on the roof dictate the following rule - the step between the bars of the crate should be 500 mm. In this case, a ventilation gap is formed, and it is also carried out additional mount vapor barrier layer. Now you know how to lay a vapor barrier on the roof, you can move on to the issue of waterproofing.
If the vapor barrier for the roof was damaged, then small cuts or holes can be stick with special tape for vapor barrier membranes.

Roofing pie scheme

Gluing joints with adhesive tape

The final version of the vapor barrier

NOTE!

A tightly stretched film is the key to good vapor barrier.

Hydro and vapor barrier of the roof - what's the difference?

Useful video

And now we invite you to familiarize yourself with the video instruction on the vapor barrier of the roof:

Conclusion

Vapor barrier is the lightest and thinnest layer of the roof. But neglect of its structure can nullify all material and physical efforts to create quality roof. So don't neglect it important element, it will significantly increase the life of the entire building.

In contact with

Vapor barrier is a layer that protects the insulation or building construction from the penetration of wet steam, which in turn leads to the accumulation of condensate on them, loss useful properties and rot when exposed to moisture. To create a vapor barrier, completely impermeable double-sided or having one correct work surface films and canvases. It is extremely important to determine exactly which side to put the vapor barrier on the insulation, a mistake at this stage provokes an accelerated destruction of building materials and significant financial costs. The main guideline is the manufacturer's instructions, but often this document is not available when buying, the choice is made taking into account the type of vapor barrier film and installation conditions.

For normal or double sided reinforced polyethylene this problem is not relevant; in other cases, the working surface is impervious to steam. Most often, the vapor barrier is laid with a smooth side to the insulation, and protected - it turns to the source of steam penetration. Depending on the type of material, these are:

Laminate on cardboard (do not recommend laying on critical objects).
Reflective side of foil and aluminum roll coatings.
Hairy or rough flatness in antioxidant films coated with viscose or cellulose.
The vapor-tight side of the membranes is usually brighter.

Mounting on various surfaces

1. Laying vapor barrier on the floor.

Protection from steam and moisture is required when insulating floors or horizontal planes, assembling structures from timber. Reflective films that return heat to the house are considered optimal for the floor. During the construction or repair of the first floors, the insulation is protected by a layer of waterproofing, and from above - by rolled vapor barrier materials, overlapped (from 10 cm and above) with gluing with metallized tape. The situation is slightly different when arranging attic floors and floors: films are turned impervious side down to protect against steam penetrating through logs or slabs.

2. Vapor barrier of ceiling structures.

Most often, the need to close the ceiling occurs in baths, saunas, kitchens, showers and other facilities with high humidity. The larger the volume of vapors emitted and the higher their temperature, the more reliable the vapor barrier is required from them. To protect the ceilings of the steam room, dense aluminum, lavsan and antioxidant vapor barrier materials are well suited, for living rooms- the same, plus the usual penofol. A prerequisite is an overlap of at least 10-15 cm and sealing of the joints; for reliability, the vapor barrier is fixed on the ceiling with a grate or brackets. In this case, the reflective or vapor-tight side is directed exclusively to the inside of the room.

3. Vertical structures.

Installation of a vapor barrier when insulating walls is necessary when: using fibrous and cotton wool insulation, erecting frame wall panels, arrangement of ventilated facades, in the latter case, in addition, it performs the functions of wind protection. In all the points mentioned, it is not recommended to choose completely impervious films, the insulation must breathe, the best option Diffusion and superdiffusion membranes are considered to allow air to pass through, but not moisture and steam. For outdoor work, the vapor barrier is laid with a smooth side to the mineral wool or other insulation on the walls, rough - towards the street. The film or webs should not sag, but excessive tension is also unacceptable. On internal vertical walls, they are held by staples or upholstery with thin strips, with the vapor-tight side towards the room.

4. Roof vapor barrier.

The vapor barrier is obligatory layer when laying a roofing pie. It prevents the accumulation of condensate in the inner insulation layer and protects the rafters from fungus. The highest possible tightness is required from the vapor barrier, preference is given to antioxidant and reflective types, the vapor-tight side is directed into the attic. Overlap - from 15 cm, as well as gluing joints and seams. An important condition is the need to seal vapor barrier materials adjacent to vertical structures.

5. Other applications.

A vapor barrier is also needed when insulating basements and balconies (areas in contact with cold outdoor surfaces. For basement and underground areas, membrane films are considered the best, the walls and ceiling of the basement must breathe, the floors are insulated from the ground. For the installation of vapor barrier when insulating balconies and loggias, preference is given to foamed polyethylene with a reflective side directed into the apartment.This is almost the only case when materials are placed end-to-end, and not overlapping, but sealing adjacent areas is still required.

Possible mistakes

In addition to choosing the wrong side, technology violations include:

1. Lack of overlaps or insufficient insulation of joints.

2. Stretching thin films, especially on structures subject to temperature changes, this leads to their rupture. But excessive sagging is also not required.

3. Lack of ventilation gaps for evaporation of condensate from the vapor-tight side of the film (a vivid example of an error is the installation of the inner cladding directly on the bottom layer of the roofing pie).

Before laying the vapor barrier, it should be calculated required amount. Usage different types undesirable, although there are no clear standards in this case. A common mistake is to buy rolls strictly according to the area of working surfaces without a margin of 15% overlap and banal damage.

There is the only option when it is not necessary to put a vapor barrier - when building a house from wooden beam, but this exception does not apply to absorbent insulation materials and floors, they always need protection. Work is carried out in a warm and, if possible, dry time years, the films are protected from getting wet in every possible way. An important condition is a tight fit of the vapor barrier to the insulation ( ventilation gaps remain on the outer, reflective and impenetrable side), voids and sagging are unacceptable. All surfaces must be clean, free of grease and dry.

In case of doubt about the correctness of the decision, which side the vapor barrier is laid to the insulation, you should read the instructions again. Reflective and rough planes are easily determined, with membranes it is more difficult. Generally, the side facing down when the roll is unrolled is considered to be the inside. Experts advise paying attention to coloring: lighter shades are observed at the sides adjacent to the insulation. But there is a variety in which the matte (most often fabric) surface is vapor-tight. If this is not enough to reveal the desired properties, then the canvas or film rolls a little on the floor, the tightly fitting side of the material will be the inside.

When building a house, it is very important to follow all the rules and recommendations of material manufacturers. A small omission can lead to many problems that will render the materials used unusable. Therefore, a smart master always adheres to the recommended algorithms at each stage.

One of the most crucial stages of building a house is insulation. It depends on it temperature regime indoors in both cold and hot weather. Important role in this process, not only the insulation itself plays out, but also how reliably it will be protected from moisture, and if it does, then how it will evaporate from there. And it depends on the correct installation of the vapor barrier.

What is installation for?

The most common insulator is mineral wool. She has whole line advantages in comparison with analogues, but cotton wool absorbs moisture very well. Condensation will always form especially in cold weather. Due to the temperature difference (from the outside - cold, from the internal space - heat), condensation is inevitable. This will entail the accumulation of water in the insulation, which will lead to loss of thermal insulation, reduced service life, the formation of fungus and mold. These factors apply to other types of insulation.

That is why a vapor barrier is installed, which should protect the insulation from unwanted condensate, and if this is formed, then quickly and in its entirety it should pass and remove the resulting moisture.

You need to be careful with the choice of option, because the wrong choice can only aggravate the situation: collect all the moisture in the insulation, and not protect it from unnecessary moisture. There are four types of vapor barrier.

Vapor barrier type A

This type of insulation material is used to remove steam and moisture only with outside. It is used for vapor barrier of roofs with an inclination angle above 35 degrees.

Vapor barrier type B

Universal vapor barrier material. It has a two-layer structure that provides reliable protection from condensate. It is thanks to its two-layer structure all moisture is retained, and weathered throughout the day. And therefore it is very important to carefully look at which side to put the vapor barrier to the insulation. As a rule, it is produced in a film version.

Vapor barrier type C

This type differs from the previous one in increased density. Use it in places where there is a possibility of increased condensation. Naturally, this type of vapor barrier is more durable, since the thickness of its layer is greater.

Vapor barrier type D

This type of insulation represents a very strong vapor barrier which is made possible by its base. The base is made of a special propylene fabric, one side of which is covered with a laminating material. It is he who provides such high strength. This type can withstand very high loads, because of this it is used for roof insulation. In addition to holding high loads, it additionally protects against leakage.

The choice of a particular brand of vapor barrier depends on many factors: climate, wall material, floor covering or floor and insulation. For example, for the roof and external walls type C vapor barrier film is better, and for internal walls a type B barrier will suffice. But these are only recommendations. For roof vapor barrier, type B vapor barrier may well be suitable, and for walls, you can safely use brand C or even D.

After choosing a vapor barrier, it is also very important to install it correctly. This is not difficult, but requires care when laying, since in most cases the vapor barrier material has an outer and inner surface in relation to the insulation.

Side selection

There are two opinions among builders on which side to lay the vapor barrier to the insulation. Some believe that the vapor barrier should be attached to only one "correct" side, others - it does not matter which side fasten the vapor barrier. All vapor barrier membranes are of two types:

for one-sided installation, this type of vapor barrier is attached only on one side;
double-sided, with which you can work regardless of its side.

Before installing the vapor barrier, you should carefully study the instructions attached to the material itself. If there is none, remember the simple rules:

The outer side of the vapor barrier has a pile, in which moisture is retained, and then evaporates. The inside is smoother. It is the smooth side that should be in contact with the insulation.
If the vapor barrier material has a different color, then the light side will be inside, and should lie on the insulation.
Usually the vapor barrier is sold in rolls. When rolling out such material, the side that will be facing the floor will be inside.

If you still have doubts, you can do a little experiment. Take a small piece of vapor barrier and cover the mug with it. hot water. Condensation will appear on the side of the film that is waterproof, which means the inside.

Installation of vapor barrier film on the ceiling

After determining the inside and outside of the vapor barrier, further how to properly lay the vapor barrier does not raise questions. But still, a few nuances need to be taken into account:

Laying vapor barrier on walls and ceilings

After installing the insulation on the walls, laying takes place vapor barrier film. Which side to lay to the insulation was discussed above. You just need to consider the following:

When laying a vapor barrier film, there is nothing complicated and special skills no need. The main thing, as in any other work, is to be careful, take your time and read the instructions of the manufacturers of the material you are working with. Then there will be fewer mistakes, the house will be warmer, the mood will be excellent and pride in your creation.

First of all, you must follow the manufacturer's instructions, which clearly describes which side to lay the windshield. If there is no such instruction, there is a series general recommendations Applicable for windproof films:

wind protection spreads to the insulation with the “fleshy” side, unless otherwise indicated in the instructions;
if both sides are the same, the film is attached with the manufacturer's logo on the outside;
wind protection without markings and distinctive qualities of one of the sides can be placed in any convenient way.

Often, manufacturers roll rolls so that the wind protection is as easy to lay as possible - in the course of unwinding the roll.

Windproof films different kind, stacked differently:

Simple windscreen. These are perforated single-layer films that can be laid on either side of the insulation, as they have bilateral vapor permeability.
Wind and moisture protection. These are two-layer films that are laid with the moisture-repellent side out. This side is smooth, often with manufacturer's markings or painted in a different (non-white) color.
Superdiffusion membranes. Such material has a multilayer structure with high water resistance and vapor permeability. It is necessary to lay the membrane on the outside of the insulation and only with the marked side out.

Floor wind protection

On internal ceilings, the film is spread over the insulation with the marking outward, and with the plain side inward.

And to protect the wooden floor from blowing cold wind from an open plinth column foundation, the film is laid on the subfloor without gaps close to the insulation. In this case, it is laid with the inscriptions down.

How to install windscreen on a roof

Single-layer windproof films are laid under the roof on either side. But two-layer - only the smooth side up.

Some films and membranes are UV resistant due to a special coating. The manufacturer must specify this parameter. Such wind protection is attached to the rafters with the colored (protective) side up.

How to install windscreen on walls

On the walls, the wind protection is placed outside directly on the insulation (marked or colored side out). It is necessary to provide a ventilation gap between the film and exterior trim. In order for the wind protection to provide a sufficient level of protection against moisture, it must be mounted horizontally from the bottom up with an overlap of at least 10 cm. Inside, a vapor barrier is laid on the walls - it is very important

Moisture in the vapor state is present everywhere - it is part of the natural water cycle. Ignoring this factor when ensuring the energy efficiency of buildings and structures is unacceptable. It is known that waterlogging reduces the thermal resistance of wall materials by up to 30%. Today proper vapor barrier- an important part of the thermal protection of a building object.

For example, cheap Asian films contain plasticizers, which significantly reduce its adhesion to the adhesive base of fastening tapes. This means that after some time such a pseudo vapor barrier will consist of separate fragments of this material.

Steam protection requirements

The vapor barrier layer must meet the following requirements.
Provide design resistance to vapor permeability at a thickness of not more than 4 mm.
To have heat resistance, excluding the “creeping” of the material on vertical surfaces at temperatures up to 50 °C.
When exposed to positive and negative temperatures maintain the calculated resistance to vapor permeation and adhesion to connecting tapes or insulated surfaces.
Maintain elasticity, be continuous and vapor-tight at joints.

The material must have instructions for laying.

Types of vapor barrier materials

Glassine and ruberoid. traditional materials are sometimes still used today. Mounted on the flooring of boards or OSB boards.
Reinforced polyethylene films. Used as vapor barriers in saunas, swimming pools and bathrooms.
Reinforced polypropylene films, simple and with an anti-condensate viscose layer. It absorbs moisture, preventing its condensation. With the onset of the warm season, moisture evaporates. These films are durable and not expensive.
Diffusion or "breathing" membranes. The most promising view, allows the insulation to “breathe”, does not allow moisture to penetrate to it from the inside. Does not require air gaps may be single or double sided.
Special materials: aluminum-coated reflective films, polyethylene foam with aluminum foil - penofol.

A wide range of such materials allows you to choose the right one at the best price. But the best do-it-yourself vapor barrier- using modern films.

Conditions for effective vapor protection

Like everyone else construction works, vapor barrier device begin with preparatory work. The heater must be dry. Surfaces must be cleaned of dust and dirt, gaps must be repaired, leveled for a snug fit of the rolled vapor barrier material and the rails securing it.

Absolute impenetrability - proper vapor barrier, this is the basic requirement. Vapor barrier is being tested on serious objects with the help of an air door, which creates a reduced pressure.

The entry points for cable bundles and ventilation fittings are the weakest point. An unsealed hole with a diameter of a few millimeters, and vapor barrier installation does not justify itself. In full accordance with the laws of physics, this is where all the moisture from the room will rush.

Pledge normal operation vapor barrier - supply and exhaust ventilation. In modern practically hermetic houses, it must be mandatory: a different approach is unacceptable in principle.

The manufacturer always highlights the vapor barrier layer of the film material and indicates the correct orientation of the film during installation.

Where is vapor barrier required?

Steam protection is used to protect structures and insulation on surfaces that serve as a barrier between a heated and unheated room.

Attic, mansard and basements, floors.
External walls of heated premises.
Bathrooms, swimming pools, baths and saunas, kitchens.

Wall vapor barrier scheme - Photo 05

This list can include other surfaces that border between warm and cold air. An exception may be buildings made of timber: the tree itself proper vapor barrier and able to absorb excess moisture. It does not form condensation.

Wood floor protection

Mandatory over an unheated basement, underground, or other unheated volume. It is always arranged from the side of the heated room.

Logs are laid on the ceiling with a step of 600 mm, insulation is tightly laid between them, and vapor barrier material is already along the logs. The finish coat is applied to it.

Throughout the area wooden floor vapor barrier must be complete. To do this, the material is overlapped, the joints are glued with a tape that has vapor barrier properties.

When installing a wooden floor concrete floors before installing the lag, the surface of the concrete floor is covered with hydroprotection with careful sealing of the joints.

Ceiling protection

Here correct ceiling vapor barrier includes two layers of vapor barrier: on both sides of the insulation. Modern films such as "Izospan" provide vapor barrier for non-insulated roofs. A special very strong film is fixed on the rafters from below and prevents moisture from entering the under-roof space.

Wall protection

An important step in the protection of the building - proper wall insulation both outside and inside. When insulating walls inside the room, the film is attached on top of the insulation, inside the room. The strips of material are glued with tape, they are additionally pressed against the frame with a counter rail, on which the interior trim is attached.

On the outside of the wall vapor barrier installation is similar: the film closes the insulation from the outside, and the outer finishing material. The film is attached from the bottom up, 100-200 mm of film is produced on the plinth to protect the adjoining wall to the plinth.

Vapor barrier orientation

All of the above jobs do not require special qualifications, but sometimes do-it-yourself vapor barrier performed in violation of the material manufacturer's instructions. If the film on both sides has the same structure and color, then both sides are considered to be working.

When the sides are different, you need to carefully study the installation requirements. rule, which side to install the vapor barrier, general: if the film has a smooth and rough surface, then the rough side - it is she who will retain moisture - is located outside, and the smooth side is to the insulation. The reflective surfaces of the film always look outward: their smooth side faces the insulation.

Vapor barrier installation

Before buying a vapor barrier material, you must clearly understand which structures need protection. There are a lot of types of it on the market, so it is important to accurately determine the one you need. Only then will it be clear how to install vapor barrier and provide maximum protection.

In most cases, it should prevent the penetration of moisture to the insulation, therefore Special attention joints must be given. Reliable fastening of the film with the base provides fasteners with a wide head or furniture staples.