Which side is the waterproofing membrane placed on the floor? Laying waterproofing on the roof. How to lay a vapor barrier on the floor

Insulating a roof or room with a heat insulator ( mineral wool, glass wool, loose foam) capable of transmitting and accumulating moisture, it is necessary to install a vapor barrier layer. Moisture that gets into the thermal insulation significantly worsens its performance properties, increasing thermal conductivity. In addition, due to the humid environment, wooden structures with which the insulation comes into contact quickly begin to rot and collapse. At the stage of preparation for insulating a roof or house, it is important to figure out which side to lay the vapor barrier against the insulation - a violation of the technology will lead to steam from the room penetrating into the thermal insulation layer.

What kind of vapor protection is needed?

Types of vapor barrier materials

The primary issue is the choice of material that will protect the insulation from moisture. Classic roofing felt and glassine, which were used for water vapor barrier, have given way to modern polymer films with different performance parameters. Membranes used in construction are divided according to vapor permeability into completely impermeable films and partially permeable (diffusion) films.

Manufacturers offer the following types of vapor barrier membranes: :

• polyethylene film (can be used to insulate a roof or floor, the barrier is vapor and waterproof);
• reinforced polyethylene film (higher strength);
• aluminum foil film (used for internal insulation, mounted with the reflective side facing the room - additionally helps to retain heat, primarily designed for use in saunas and baths);
• film with anti-condensation coating (prevents moisture condensation, intended for installation in structures with metal elements prone to corrosion - corrugated sheets, metal tiles, etc. the film is mounted with the treated side facing the heat insulator).

Reinforced polyethylene film If, when insulating rooms in a house, a completely impermeable film is used to create a vapor barrier, it is necessary to provide effective ventilation of the rooms that can remove excess moisture outside.

Vapor barrier films with a porous structure differ in their ability to diffuse. Due to the pores in the barrier, moisture from the insulation leaves to the outside, due to which the heat insulator retains its operational properties, and those in contact with it metal constructions do not rust, wooden ones do not rot. Among vapor-permeable membranes there are differences :

1. Pseudo-diffusion. During the day, up to 300 g/m2 of vapor is passed through.
2. Diffusion. The amount of evaporation passed per day ranges from 300 to 1000 g/m2.
3. Superdiffusive. The evaporation rate exceeds 1000 g/m2.

The vapor barrier film of the first type is classified as effective protection from moisture and are used for internal insulation of structures (from the room side). If a pseudo-diffusion membrane is mounted on top of a fiber insulation on an external wall, the vapor barrier will trap moisture in the insulation. Diffusion and superdiffusion membranes, which simultaneously serve as a wind barrier, are suitable for façade insulation.

Principles for installing a vapor barrier

Laying a vapor barrier is an important stage in the work of insulating structures with fibrous materials that can accumulate moisture. The work is carried out as part of the repair or reconstruction of the house or at the stage of preparation for finishing new construction. You need to know how to properly fasten membrane sheets together to ensure a continuous layer that protects against moisture penetration, and how to attach the film to structures. Before laying the vapor barrier film, it is also necessary to determine which side it needs to be placed towards the insulating material.

Preparatory stage

To insulate a block or wooden house or arrange a bathhouse, thermal insulation materials are used, which must be protected from moisture accumulation. For this purpose, a material that does not allow evaporation is installed on the walls inside the house, on the ceiling or floor, on the inside of the roofing pie. Or a diffusion membrane for facade insulation.

On preparatory stage you should choose a vapor barrier option taking into account the installation features and requirements for the characteristics of the film. Popular options include Izospan (and its analogue Megaizol), a membrane material with high performance parameters. The manufacturer offers a line of membranes with various technical indicators, which allows you to choose a material depending on its purpose - vapor barrier for roofs, ceilings, wall structures made of wood or concrete.

Those who plan to build a bathhouse, not without reason, believe that foil film will reliably protect the mineral wool insulation from getting wet and help maintain high temperature indoors due to the reflection of thermal radiation. Along with the classic “insulation + vapor barrier” scheme, today ready-made non-combustible heat-insulating mats with a foil-coated vapor-proof surface are used.

Correctly attaching reflective vapor barrier

Before laying a vapor barrier, it is necessary to properly prepare the surfaces of the structures. The preparation technology depends on the material from which the walls, floor, ceiling or roof are made. It also takes into account what kind of work is being carried out at the site - construction or repair :

1. When building a wooden house, all wooden structural elements must be treated with compounds against rotting, pest damage and fire.
2. During the repair work, the finishing is first dismantled, the surfaces are cleaned, while:
   • wooden structures are treated with an antiseptic and fire retardant.
   • Concrete and block structures are treated with an antiseptic if they are damp and there is a risk of mold, as well as in wet rooms.

Because of improper preparation wall structures, ceilings or rafter systems can become unusable over time or become a source of fungal spores that can provoke allergies, asthma attacks, and exacerbation of respiratory diseases.

How to install a vapor barrier on a ceiling

Installation of a vapor barrier layer on the ceiling is required when insulating a flat or pitched roof in a house without an attic, when insulating a basement, as well as residential premises above which a cold attic is located. The ceiling in the bathhouse is also insulated and vapor-insulated. Before laying a vapor barrier on a roof made of a concrete slab, on a reinforced concrete or wooden floor from the inside, the surface of the structure should be prepared.

The fabric made of film or pseudo-diffusion membrane must be solid so that there are no joints through which moisture can penetrate into the insulation. If the width of the roll material is not enough, the strips will have to be joined together. The recommended overlap of the canvases is from 10 to 20 cm, while the joints on both sides are carefully taped with reinforced construction tape.

Fastening the vapor barrier membrane The foil film sheets are laid without overlap - end-to-end, and the seam is taped with aluminum tape.

If the base of the roof or ceiling is a wooden structure, you first need to lay a waterproofing membrane (solid sheet) and attach it to the base (a vapor barrier material can be used).

Then, in the spaces between the floor joists or rafters, a heat insulator is placed in the form of mats or rolled material made of mineral (basalt) wool. After this, you can lay a vapor barrier on the ceiling. If the thickness of the heat insulator corresponds to the thickness of the logs, you should nail a counter-lattice made of slats to create a ventilation gap.

The vapor barrier should be placed on the ceiling in such a way that the fabric extends along the entire perimeter of the walls and that all corners are closed. The joints of the canvases should be on the floor joists - this will allow them to be securely fixed. To properly install a vapor barrier on the ceiling, monitor the tension of the canvas, it should not sag .

Ceiling installation

We will also consider how to lay a vapor barrier on concrete floor. To insulate a ceiling or flat roof made of a concrete slab from the inside, you need to attach a waterproofing coating (vapor barrier film) to it using self-adhesive tape, and then install a sheathing made of bars or a metal profile.

The correct height of the sheathing should be selected taking into account the thickness of the insulation and the ventilation gap, the installation step should be 1-2 cm less than the width of the insulation, so that mats made of insulating materials fit into the cells at odds. How to attach a vapor barrier to the sheathing will be described in detail below.

How to lay a vapor barrier on the floor

Installation of a vapor barrier membrane on the floor is similar in technology to how vapor barriers are installed for walls and ceilings. After preparing the base of a wooden floor when insulating along the joists, before laying the vapor barrier on the floor, a waterproofing carpet is installed, which should go around the joists. Then a thermal insulator made of mineral wool is inserted between the joists. After which the vapor barrier is laid, it is important to know how to lay the film correctly.

The overlap of the sheets of rolled material should be at least 10 cm, with the joint taped on each side. The resulting canvas is secured in such a way that the overlaps lie on the floor joists, and along the entire perimeter the evenly stretched canvas extends 5-10 cm onto the walls.

Insulated floor with air gap

Before laying a vapor barrier on a concrete floor, it is necessary to install a sheathing, between the elements of which the waterproofing and insulation will be placed. Further work is carried out according to the standard scheme.

Fastening principles

If concrete structures or wooden walls are insulated, it is necessary to install sheathing made of bars. It is convenient to attach the film to the resulting sheathing, to the ceiling or rafter system using staples and a construction stapler. You can also secure the vapor barrier material with nails with wide heads or pads under the heads. It is advisable to use galvanized nails - they do not rust. Films and membranes are placed on concrete structures using a special connecting tape.

Overlap when installing vapor barrier

In order to properly fasten the vapor barrier, the canvas should be carefully pulled, and the fastening elements should be placed in small increments - no more than 30 cm. Installation rules require careful attention to the fastening of the canvas around the perimeter - it is spread and fixed in such a way as to exclude the possibility of moisture penetrating into the insulation.

Before attaching the vapor barrier, make sure that the sheet is positioned right side to thermal insulation.

Which side to install the vapor barrier material

Let's consider which side of the film or membrane is laid to the insulation :

• polyethylene film (simple or reinforced) can be attached to either side - this does not affect the functionality of the barrier;
• the foil film is placed with the shiny side facing the room so that the barrier reflects heat;
• the antioxidant film is attached with the treated side to the structures, the fabric side to the room;
• the membrane should be facing the smooth side towards the heat-insulating material, and the rough side towards the room.

Rule for laying vapor barrier to insulation If the front side of the membrane looks similar to the back side, and it is difficult to determine how to properly lay the material, you can conduct an experiment. Cover the bowl of boiling water with a small piece of membrane - whichever side the condensation appears on is the side that is waterproof; it should be facing the insulation.

It is important to know which side to lay the vapor barrier against the insulation if the membrane is used to install a waterproofing barrier - front or back. Thermal insulation “pie” with internal insulation it is mounted in such a way that the smooth side of the membrane faces the insulation on both sides. That is, the rough layer of vapor barrier should be facing towards the room, and when installing a waterproofing carpet - towards the structure that is being insulated.

Installation features

It is important not only to install the vapor barrier correctly, but also to ensure ventilation gap between the vapor-tight layer and the cladding of the structure for finishing, for which counter battens are placed along the sheathing. Moisture settling on the rough side of the laid vapor barrier sheets will evaporate naturally without damaging the finish.

Diagram of an insulated roof with a ventilation gap

If the vapor barrier is installed correctly, the insulation is reliably protected from moisture. Almost half of the problems associated with freezing and damage to structures are associated with defects in the installation of the vapor barrier.

Which side should the vapor barrier be laid against the insulation?

Preface. When building a private house, special attention should be paid to vapor barrier of the ceiling, floor, walls and roof. If this important step is skipped, the building's structural elements will not last long. We’ll talk further about why it is important to install a vapor barrier in a private home and how to do it correctly.

Review of insulation materials

Properties of Rockwool Light Butts

Minvata Izover: characteristics

Knauf insulation: characteristics

Properties of Ursa PureOne mineral wool

Why do you need a vapor barrier for insulation?

A special film that protects the heat-insulating material from moisture is necessarily included in the “pie” of the walls or roof. The fact is that due to the difference in temperature, especially in winter, condensation settles on the walls and ceiling indoors and outdoors. As a result, the heat insulator gets wet and stops performing its functions. The house is getting cold. In addition, moisture leads to damage to the structural elements of the building.

Depending on the variety, the cost of the material may vary. For example, a regular vapor barrier polyethylene film costs about 500 rubles per roll. The foil version will cost about 1400-1800 rubles. A three-layer diffusion membrane will cost about 4000-5000 rubles. The popular vapor barrier “Izospan” will cost about 800-1000 rubles. per roll.

Types of vapor barrier materials

Vapor barrier in a frame wall. Photo

There are only three main types of films designed to protect mineral wool or expanded polystyrene from moisture:

Standard. The cheapest and not particularly durable type of vapor barrier. In most cases, this is ordinary thick polyethylene film.

Foil. It is more expensive than polyethylene, but at the same time, in addition to the vapor barrier itself, it performs another function - it reflects heat back into the room. Owners of country houses are often interested in which side to lay the vapor barrier on the walls and ceiling. This question usually arises in relation to this variety. Let's look at how such a film is actually mounted below.

Membrane. Features limited vapor barrier. This allows you to control the removal of moisture from the room.

Basic rules for laying vapor barrier

Of course, before you go to the store to buy film, you need to make all the necessary calculations. This procedure is completely easy to perform. All you need to do is calculate the area of ​​all structural elements of the house that require protection. The calculation is made taking into account the width of the vapor barrier film and the required overlaps.

How to distinguish the inside from the outside

Photo of vapor barrier under magnification

If the manufacturer’s instructions are missing or do not contain the necessary information about which side of the film is considered internal, then you should independently determine this based on external factors. Please note the following:

If the waterproofing film has a different color on both sides, then the light side of the isospan is laid against the insulation;
. The side of the waterproofing that faces the floor when rolled out is considered internal and should face the insulation;
. External side it is made fleecy so as not to allow moisture to pass through, and the inner side is smooth and is laid towards the insulation.

Which side should the vapor barrier be placed on the insulation?

Of course, it’s also worth knowing how to install this type of vapor barrier. In this case, as in all others, the sheathing is initially installed. The sheets are mounted on it and secured with self-tapping screws. The joints are taped with tape.

Which side to lay the vapor barrier on the floor

Video. Which side to lay Izospan on the insulation

(votes, average: out of 5)

Vapor barrier: everything you need to know about protecting insulation from moisture

What is vapor barrier, why is it needed, and how is it performed? I've thought about this before. Now, having gained experience in this matter, I will accurately convey the technical aspects and describe step by step the technology for installing vapor barriers.

The vapor barrier affects not only the effectiveness of the insulation, but also the durability of the structure

Why do you need moisture protection?

Why do you need a vapor barrier at all? As you might guess, its purpose is to protect surfaces from steam. Moreover, we are talking not only about visible steam, but also moisture, which is always present in the air.

Inside the home, the humidity level is almost always higher than outside, which is explained by cooking, washing and taking water procedures. Since steam moves towards the cold - out, excess moisture can significantly reduce the service life building structures and insulation efficiency.

Insulation of walls from the inside with mineral wool must be done using a vapor barrier film

Protection is necessary in the following cases:

• When insulating walls from the inside with mineral wool. As is known, the level of vapor permeability and moisture absorption of mineral wool is quite high.
  Therefore, the absence of a vapor barrier can lead to the accumulation of moisture inside the insulation. This in turn will lead to a decrease in the efficiency of the insulation, dampness of the walls, the formation of fungus, etc.;

Frame walls insulated with foam plastic from the inside must be protected from moisture with a vapor barrier

• When insulating frame structures. Vapor barrier is necessary for frame walls, wooden floors and pitched roofs, not only when using mineral wool insulation, but also polymer insulation, which has zero vapor permeability.
  The fact is that zero vapor permeability of thermal insulation leads to the fact that all moisture rushes into the elements of the wooden frame. As a result, the tree quickly becomes unusable;

Vapor barrier film must be used when insulating floors

• When insulating floors. In this case, vapor barrier allows you to protect the insulation from rising steam.

If mineral wool is used inside partitions, vapor barrier need not be used, since there are no temperature differences in the partitions that could lead to the formation of condensation.

As we found out, the vapor barrier should not allow air to pass through, which carries moisture. Therefore, the vapor barrier film should not be confused with waterproofing, which often has the ability to allow air to pass through.

Currently used following materials for vapor barrier:

Polyethylene

Polyethylene films are the cheapest vapor barrier option. As a rule, polyethylene film is used for waterproofing interfloor ceilings and walls.

Single-layer polyethylene film is cheap, but not durable

Kinds. There are several types of polyethylene films:

• Single layer. The cheapest, but not durable, and also unstable to mechanical loads;
• Reinforced. They are a three-layer material. The middle layer is made of fiberglass mesh.

Reinforced film has tensile strength

Thanks to the reinforcing layer, the film has higher strength and durability;

• Foil. The main feature of these films is their ability to reflect heat.

The photo shows a polypropylene vapor barrier film - it has high strength and long service life

Polypropylene

Polypropylene vapor barrier films are the most popular, as they are superior to polyethylene films in all respects. In particular, they are stronger, more durable, and resistant to UV radiation and temperature changes.

Another feature is that these films usually have a two-layer structure. As a result, one side has a rough surface.

One side of the polypropylene vapor barrier has a rough surface that retains moisture

This is done so that the villi retain moisture on the surface of the coating and thereby allow it to evaporate. Beginners often ask which side to put the vapor barrier on?

The material is laid with the smooth side against the insulation, and the rough side against the cladding. True, if you mistakenly attached the canvas with the rough side to the insulation, this is not a critical mistake, since in any case the material does not allow moisture to pass through.

Therefore, a ventilation gap is required between the film and the finishing material.

Vapor barrier axton from the French manufacturer Leroy Merlin has proven itself as a reliable and durable material

Price. Below are the prices for popular vapor barrier materials that have proven themselves well:

Nuances of installing vapor barrier films

Basic Rules

So, we have figured out the types of vapor barrier materials. However, the quality and effectiveness of steam protection depends not only on the type of material, but also on the quality of its installation.

Therefore, finally, we will consider the technology of laying vapor barriers. But first, I will give some important installation rules:

• The vapor barrier is attached to the housing side. Since steam flows move from inside the room to the outside, vapor protection is always installed with inside, which allows for a sealed circuit;

The vapor barrier is always mounted on the inside of the insulation

• The film must be positioned correctly relative to the insulation. I have already said above which side to lay the vapor barrier against the insulation - smooth towards the thermal insulation, rough towards the finishing;

Diffuse membrane allows moisture to pass in one direction

• On the outside, the insulation is protected by waterproofing. It is almost impossible to provide complete protection of thermal insulation from steam. To allow penetrating moisture to leave the insulation, it is covered on the back side with a waterproofing diffusion membrane.
  This material is capable of transmitting moisture only in one direction;
• The vapor barrier coating must be airtight. To ensure that the film does not allow steam to pass through, it is necessary to seal the places where it is adjacent to the frame, and also to glue the joints of the films with double-sided adhesive tape.

Installation technology

Let's look at the film installation technology using the example of vapor barrier for frame-type walls. This procedure can be divided into several stages:

Instructions for using vapor barrier are as follows:

Sources:

Often waterproofing is installed water-repellent side in the direction from which moisture can penetrate. For example, roof waterproofing is laid on top of the insulation with a water-repellent layer facing up. And on the floor and walls, the water-repellent layer is directed away from the insulation, while waterproofing can be used both inside and outside the building.

How to determine the water-repellent side for different types of waterproofing:

Read also: Which side to lay Ondutis films

Which side is the waterproofing placed on the floor?

Depending on which side protection from moisture is needed, the waterproofing spreads:

• water-repellent side down - when laying under moisture-absorbing insulation on concrete or earthen floors;
• water-repellent side up - directly under the screed to protect floors in very wet areas.

Read also: Installation of waterproofing for the floor

Which side to lay waterproofing on walls

The principle of waterproofing walls is the same as that of floors. If you need to protect the insulation or walls from an internal source of moisture, the waterproofing is attached inside with the water-repellent side facing the room. And to protect the walls from the outside, the moisture-repellent layer should be directed towards the street.

See also: Video of wall waterproofing

Which side is the waterproofing placed on the roof?

The water-repellent side of the roof waterproofing should be directed outward from the insulation. After all, with its help, the insulation is protected from moisture penetrating from the outside - when precipitation or condensation forms under the roofing. The rough side should absorb moisture from the insulation and evaporate it.

See also: Roof waterproofing video

Which side to lay waterproofing under metal tiles

Due to its characteristics, metal roofing (made of corrugated sheets, metal tiles) requires special waterproofing - special anti-condensation films. This the only kind waterproofing, which is attached with the fleecy side facing out. It is thanks to the moisture-absorbing outer layer that protection is achieved metal roofing from corrosion - all absorbed moisture quickly drains away without lingering.

See also: Video of waterproofing under metal tiles

Do you need waterproofing on the ceiling?

The ceilings in the rooms are covered only with vapor barrier; waterproofing on the inside of the rooms is not used even in the bathroom or sauna. Otherwise interior decoration will regularly get wet - because the waterproofing will remove condensation from the insulation into the room.

January 12, 2017

Implementation of each new technology in the construction industry provides an opportunity for a person to improve their own home, which as a result becomes even more reliable, safe and comfortable. But for this it is also necessary to strictly adhere to established standards and construction norms during the construction of a house.
One of the main structural elements of a house that ensures comfortable living in it is the roof. Therefore, it is imperative to know the technology of laying a vapor barrier layer on the roof.

The need to install a vapor barrier

The steam generated inside the room mixes with warm air and, according to the laws of physics, rises. But, since its further advancement is impeded by the roof of the house, it penetrates the thermal insulation layer, beginning its destructive effect.

In winter, due to the sharp difference in internal and external temperatures, steam will be contained in the insulating material. As a result of sub-zero temperatures, the steam will first turn into frost, then into ice, respectively, the thermal insulation layer will freeze and remain in this state until the onset of heat, then thaw. As a rule, the consequences of such a process are the complete loss of the protective properties of the insulating material, that is, its unsuitability for further use.

In order to prevent failure of the insulation after just a year of operation, it is necessary to install a vapor barrier on the roof. The vapor barrier material will prevent moisture from entering the insulation and, accordingly, will significantly extend its service life.

Materials used to construct a vapor barrier layer

Previously, the only material installed to protect the roof from moisture was glassine. Today, a wide variety of building materials are used to construct a vapor barrier layer on the roof.

• Regular low density polyethylene film. Due to its low density, experienced roofers do not recommend using it in private housing construction, as there is a high risk of damage during installation and operation.
• Polyethylene film reinforced with a polymer mesh. This is a denser, stronger insulating material, which is most often used for arranging the roofs of agricultural enterprises. It is also not recommended as a vapor barrier for roofing in multi-apartment and private housing construction, since microscopic cracks form at the junction of polyethylene with reinforcing elements, through which steam can penetrate.
• Bag fabrics made from polypropylene threads, which are subsequently laminated using molten low-density polyethylene. The thickness of the vapor barrier material is half that of a reinforced polyethylene film. This vapor barrier material is used for arranging cold roofs.
• Aluminum foil, which has zero vapor permeability.
• Cardboard laminated on one side with polyethylene film.

A vapor barrier fabric made of several protective layers is used for roofs over rooms in which swimming pools, showers, laundries, etc. are installed.

Which side is the vapor barrier installed on?

• A standard vapor barrier film consists of two layers. At the same time, on the one hand, it has a rough surface that holds back drops of condensation, on the other, it has an absolutely smooth surface. It is the smooth side of the vapor barrier film that is adjacent to the insulating material, and the rough side is directed into the room.
• When using foil film for vapor barrier, which is intended not only to protect insulation, roofing, and foundations, but also to return thermal energy back into the room, it is laid with a reflective surface in the room.
• A vapor barrier membrane that can allow air to pass through, protecting the foundations and roofing from moisture penetration, provides the structure with the ability to “breathe.” When using a double-sided vapor barrier membrane that has identical surfaces, it can be laid on either side. If a one-sided membrane is used to install a vapor barrier, then the reverse side of the material is indicated by the manufacturer.

When purchasing any type of vapor barrier material, be sure to read the instructions for its use provided by the manufacturer.

Basic rules for laying vapor barrier film

After determining which side of the room or insulation you need to lay the vapor barrier material on, you can proceed directly to its installation. In this case, the following rules must be observed:

• First– installation of thermal insulation is carried out, soundproofing material, then a vapor barrier film.
• Second– the film should be well stretched, there should be no sagging areas.
• Third– the vapor barrier material is attached using ordinary adhesive tape (adhesive tape). You can also use nails with a wide head (30 cm pitch) or a furniture stapler as fastening elements, which will greatly facilitate the work and reduce the time it takes to complete it. The film can be secured with wooden slats, which are screwed in increments of 30 cm.
• Fourth– individual sheets of vapor barrier film are laid with an overlap of up to 15 cm. In this case, it is necessary to make ventilation gaps up to 5 cm wide.
  This general rules use of vapor barrier material, but when laying it on different reasons, roofing has its own characteristics.

Roof vapor barrier

Providing moisture protection to the walls of the house is only 50% of the work, since the bulk of the evaporation is directed upward. It is also impossible to avoid the formation of condensation as a result of heavy atmospheric precipitation. As a rule, the roof of the house takes the brunt of the impact.

It is also necessary to understand that poor-quality installation of vapor barrier performed on the roof will contribute to a decrease in the temperature inside the house, an unfavorable odor, the formation of dampness, mold, corrosion of metal structural elements, etc. Therefore, it is quite important to use high-quality vapor barrier material and install it correctly.

To protect the roof of a house, experienced roofers recommend using membrane-type vapor barrier materials that allow air to pass through and do not allow moisture to pass through. Membrane vapor barrier will also help remove excess moisture from insulation material. Membranes of a double-sided design will work on both surfaces of the roof covering.

Sequence of materials

When arranging the roof of a house, it is important that the construction materials are in the following sequence:

1. Roof covering
2. Counter-lattice
3. Lathing
4. Waterproofing
5. Rafters
6. Insulation
7. Vapor barrier
8. Roof filing

Vapor barrier is one of the important points when building a house, as it protects the elements of the main structure of the house from mold, rot, rust and other negative influences that help reduce their service life. And also a high-quality layer of vapor barrier will provide optimal temperature regime for a comfortable stay.

Very often, various concepts are confused in the building materials market; even sales consultants can give incorrect information. The names used are waterproofing, vapor barrier, hydrovapor barrier, diffusion membranes, breathable membranes, wind protection, etc.

Water vapor barrier for roofing

How to correctly name materials taking into account their properties and what are their differences?

1. Waterproofing. These materials allow steam to pass through, but do not allow water to pass through. Modern membranes are manufactured using innovative technologies. Depending on the type they have various indicators in terms of vapor permeability, the higher the vapor permeability values, the better performance characteristics. May be called breathable or diffusion membranes. They do not interfere with the removal of steam from the insulation and protect it from condensation drops. Of course, wind protection is also done at the same time.

   Roof waterproofing

2. Vapor barrier. Does not allow steam or water to pass through. Its task is to minimize the amount of steam penetrating into the insulation from residential premises. Accordingly, hydrovapor barrier is the same vapor barrier.

   Vapor barrier of complex roof

Confusion also arises because there are traditional materials (roofing felt, polyethylene film, aluminum foil) that are called waterproofing. But they do not fully correspond to modern membrane water vapor barrier materials. And roofing felt, and polyethylene film, and aluminum foil do not allow steam and water to pass through, from the point of view modern coatings they should be called vapor barriers or hydrovapor barriers, which are actually the same thing. And membrane waterproofing allows steam to pass through and allows the thermal insulation of the roofing pie to dry. Such confusion arose due to the desire of manufacturers to advertise their products using all available methods. Developers are attracted by unfamiliar “scientific” names; they buy the most expensive materials, although there are many cheaper materials on the market with the same physical characteristics.

Types of waterproofing

ISOSPAN AQ proff	Moderately flammable and non-flammable material, can work at temperatures -60°C +80°C, roll width 1.6 m, length 43.75 m.	4600 rub./roll.
	Equivalent diffusion resistance 0.03 Sd/m, vapor permeability 1300 g/sq.m/24 hours. Roll width 1.5 m, length 50 m.	7700 rub./roll.
JUTA Yutavek 115	Roll length 50 m, width 1.5 m. Temperature range -40°C +80°C, equivalent thickness of diffusion resistance 0.037 Sd/m. Moderately flammable.	4000 rub./roll.
	There is 75 m2 of membrane per roll, density 140 g/m2. Highly flammable material, can operate at temperatures of -40°C +80°C.	8400 rub./roll.

Types of vapor barrier

ISOSPAN FD proff	Vapor permeability 0 sq.m.h.Pa/mg, use at temperatures -60°C +80°C is allowed. Roll width 1.2 m, length 58 m. Moderately flammable and moderately flammable.	RUR 3,650/roll
JUTA Yutafol N 96 silver	Roll length 50 m, width 1.5 m, density 96 g/m2. Temperature stability -40°С +80°С., tensile strength 210 N. Highly flammable.	1300 rub./roll.
	Equivalent thickness of diffusion resistance 150 Sd/m, highly flammable, moderately flammable. Vapor permeability 3.1 × 10^-6 mg/(m×h×Pa).	9500 rub./roll.
	Vapor permeability 19 g/sq.m/24 h, can be used at temperatures -55°C +80°C. Density 60 g/m2.	1000 rub./roll.
TYVEK AIRGUARD REFLECTIVE	Roll length 50 m, width 1.5 m. Has a reflex layer, diffusion resistance thickness 2000 Sd/m. Can operate at temperatures -40°C +80°C.	RUB 13,400/roll

Why do you need hydro- and vapor barrier roofing?

Unfortunately, even many professional builders intentionally, to increase the estimated cost of work, or out of ignorance, incorrectly use various insulating membranes during roof construction. When, what and for what purposes should steam and waterproofing protection be used?

Non-insulated roofs

Such roofs can have different coatings; depending on their characteristics, a decision is made on the need for additional insulating materials.

1. Roofing made of metal tiles, profiled sheets, asbestos-cement slate, natural or artificial piece tiles.

   Metal roofing does not require vapor barrier

   There is no need to use hydro-vapor barrier under these roofing coverings, although there are often cases when roofers install it under metal tiles and profiled sheets. It's a waste of time and money. The fact is that condensate evaporates without problems due to natural ventilation, and any additional protection only complicates this process. A vapor barrier will never completely protect the coating from steam penetration; there is no way to make the protection airtight; in any case, air will find cracks and enter the under-roof space. If you make a vapor barrier layer, and even without special additional vents, then the operating conditions of the roofing coverings will only worsen, and accordingly, their service life will decrease.

2. Soft roofing coverings.

   Waterproofing is required for soft roofing

   Here it is recommended to use waterproofing as an additional guarantee of the tightness of the coating. The point is that it's soft bitumen shingles laid on a continuous sheathing, natural ventilation processes are significantly slowed down. A constantly wet OSB board or plywood loses its original properties. Surfaces become deformed and roof leaks increase even more. To reduce the risk of such negative problems, simple waterproofing is used. It does not allow steam or water to pass through.

Everything is clear with uninsulated roofs; now we should consider more complex types of roofing pies.

Warm roofs

These are very popular types of roofs, allowing the use of attic spaces for residential attics. Modern materials are used as insulation; depending on their type, certain protective membranes are recommended. How do the technical parameters of thermal insulation affect the choice of hydro- and vapor protection?

Styrofoam

This means not only polystyrene foam, but also all its derivatives: expanded polystyrene, penozol, etc. There are quite a few varieties polymer insulation, in terms of their performance, they fully meet the requirements of most developers. It is generally accepted that these insulation materials have two significant drawbacks: flammability and the release of harmful chemical compounds into the air. Is it really? Modern foam plastics do not support open combustion; they melt when the temperature increases, and begin to burn when heated to more than +800°C. For your information, wood ignites at a temperature of approximately +400°C. So, this indicator does not have a noticeable effect on the fire safety of the house.

Using expanded polystyrene as roof insulation

Now a little about the release of harmful substances. You need to know that absolutely all chemical building materials emit harmful compounds in one quantity or another. This includes varnishes used for furniture or flooring, plastic decorative elements and wall decoration, etc. But according to these parameters, they are approved for use by government regulatory organizations; foam plastic also has this approval.

Example of roof insulation

Conclusion - use foam plastic to insulate roofs without any worries. Compared to mineral wool, it has very important advantage– does not completely absorb moisture. For a warm roof with foam plastic, there is no need to use steam and waterproofing, and this significantly reduces the cost roofing works.

Mineral wool

A very fashionable thermal insulation material for roofing at the moment. We will not dwell on the advantages; we will point out the main operational disadvantage: mineral wool reacts extremely negatively to an increase in relative humidity. It sharply increases thermal conductivity, heat saving indicators tend to zero. In addition, wet mineral wool significantly accelerates the process of rotting of wooden structures of the rafter system.

Mineral wool reacts extremely negatively to increased relative humidity

For such a roofing pie, it is necessary to use hydro- and vapor barrier. But this should be done with skill, technology errors lead not only to deterioration of microclimate parameters in attic rooms, but also cause destruction of the rafter system, structural elements rot and lose their load-bearing characteristics. The roof has to be not only repaired, but completely covered. The cost of such work is much higher than the cost of constructing a new roof covering.

Roof insulation with mineral wool involves the use of hydro- and vapor barriers

TechnoNIKOL stone wool: insulation characteristics

Negative consequences of improperly installed water vapor barrier

Water vapor barrier is installed on the inside of the attic space. Its function is to minimize the amount of steam entering the mineral wool layer. It is impossible even theoretically to make the protection completely airtight.

Attaching the vapor barrier

What consequences incorrect installation water vapor barrier?

1. A sharp increase in the thermal conductivity of structures makes it difficult to maintain comfortable temperatures in the room. Due to the fact that air circulates least in the corners, these areas are considered dead zones. In corners, the temperature of wall coverings often drops below the dew point, and steam condenses on surfaces. Long-term high humidity creates ideal conditions for mold growth.
2. On finishing coatings stains, dirty spots, etc. may form on the ceilings and walls of the attic. This indicates more complex problems with the insulating layer of the roof. The reason for the occurrence of unpleasant situations is the wrong choice of water vapor barrier or gross violations of installation technology.

   At best, they do not allow water to pass through, and steam freely enters the mineral wool. In winter, condensation periodically freezes/thaws in the upper part of the insulation, water flows down and over time all the mineral wool becomes wet. Water conducts heat well (thermal conductivity increases) and gradually penetrates the surface of the upper finishing of the walls of the room. They have to be repaired or completely replaced. But it is not advisable to make repairs without eliminating the cause; after a short time, the problem will reappear. The only correct solution is to completely redo the water vapor barrier and insulation, and this is time-consuming and expensive.

3. Insufficient thickness of the insulating layer. Unfortunately, often the thickness of the thermal insulation layer does not exceed ten centimeters. Building codes recommend for the Moscow region a mineral wool thickness of more than 15 cm; if it is less, then the wool will inevitably freeze, regardless of the quality of the water vapor barrier installation. As a result, the same negative consequences appear as those described above.

   If the thickness of the standing insulation is insufficient, a number of negative consequences will arise

Practical advice. A warm roof is exactly the type of house design during the construction of which it is better to play it safe than to try to simplify existing technologies.

Currently, there is a large selection of different modern hydro-vapor barriers, their characteristics are not much different, but the price varies widely. You can use modern nonwoven materials manufactured using the most innovative technology. But practitioners advise doing something smarter - using traditional, cheap and very effective materials as a water vapor barrier.

1. Polyethylene film. It is better to take a thickness of at least 50 microns; the film perfectly protects mineral wool from steam. The only significant drawback of polyethylene film is a negative reaction to hard ultraviolet rays. Under their influence, the intermolecular bonds of the polymer chains are disrupted, the film loses its plasticity, and cracks under minor loads. Special additives slightly increase the resistance of the material to UV rays, but do not make it completely resistant. There are no problems for the roofing pie; the polyethylene film is completely protected from harmful influence ultraviolet rays, which increases its service life to hundreds of years. Another advantage of this material is that the sleeve width can reach three meters, and after cutting, the size of a single film increases to six meters. This makes it possible to finish most mansard roofs no seams at all or with a minimal number of them. Fewer joints means fewer points of moisture penetration into the mineral wool layer.

   Polyethylene film

2. Aluminium foil. It is also completely sealed against moisture vapor, but this material has three significant drawbacks. The first is the high cost compared to plastic film. The second is low levels of physical strength. Third, the foil cannot stretch and breaks through with slight vibrations of the rafter system. This complicates the use of the material; in total, in terms of actual performance indicators, it is much inferior to polyethylene film.

   Smooth aluminum foil 150 microns

3. Water vapor barrier based on coatings with liquid rubber or modified bitumen. In the construction of warm roofs for residential premises it is rarely used due to unpleasant odor, but technical or industrial warm rooms can be finished with them.

   Bitumen mastic for roofing

Important. The prospect of building a warm roof should be considered at the design stage of the house. This will help you choose the optimal dimensions of the rafter legs and the pitch between them, determine the need for installation and the parameters of the slats for the interior decoration of the walls of the attic premises. Another advantage of this approach is that the rafter system is made with a minimum number of different stops and supports, thereby reducing the number of points of probable depressurization of the protective layer.

How to properly install hydro-vapor barrier

A very important point when building a warm roofing pie. Water vapor barrier is designed to limit the penetration of water vapor from the living spaces of the attic into the thickness of the mineral wool. We have already mentioned above that it is better not to insulate the roof at all than to do it incorrectly. Practice shows that if technology violations are critical, then the rafter system will have to be repaired in 7–10 years. What is a warm roof repair? This includes dismantling roofing coverings, waterproofing (vapour-permeable wind protection), and removing thermal insulation. Next you need to go inside the premises, shoot external finishing walls and water vapor barrier. Final stage– revision of the rafter system and replacement of failed load-bearing elements.

How should you make a roofing pie to avoid such problems?

Step 1. Carefully inspect the material and place it correctly. All inscriptions should be facing the room, and not vice versa. You need to start laying the water vapor barrier layer of the pie from the ridge part. Roll out the roll so that it is located in the middle of the structure. You need to work on a stepladder and with an assistant. Roll out the roll in parts, making preliminary fixations every 1.5–2.0 m. The final one should be performed only after the material is completely leveled, there are no folds or kinks.

All signs must face the room

Step 2. Secure the water vapor barrier with a construction stapler, the distance between the staples is approximately 25–30 cm.

Fastening the blade

Important. There is no need to nail the staples too often; this will only increase the number of holes. The material is light and fits without problems.

It is advisable to install thermal insulation after covering the roof. During roofing work, it is necessary to lay out a vapor barrier (wind barrier) and secure it with strips. Then put a counter-lattice on the slats, it will provide ventilation of the under-roof space, condensed water will be naturally removed. Roofing materials are laid after preparing the vapor barrier layer.

Some builders do the opposite, first installing a water vapor barrier inside the premises, and then laying insulation and covering the roof. This order of work cannot be considered optimal. The fact is that if mineral wool gets wet due to precipitation, it will have to be removed and dried. This greatly complicates the construction of a warm roof and deteriorates its quality.

Step 3. The second layer is rolled out parallel to the first; you should gradually move down towards the cornice. After alignment, secure the membrane with staples.

Step 4. Very carefully seal the junction of the water vapor barrier to the chimneys.

The junction of the water vapor barrier to the chimney

Use special sealing tape for this; never buy low-quality additional materials. If the adhesive tape has insufficient adhesion characteristics, then after a short time it will come off, and a large gap will form between the surface of the chimney and the water vapor barrier. It is impossible to notice it in time due to the finishing interior walls, and the appearance of visible condensate leaks will require complex repairs.

Step 5. The overlap between the rows should be within 10 cm, glue them carefully.

The overlap between the rows is taped

Experienced builders advise first nailing small slats to the rafters in these places. For what? Firstly, they will create a gap between the mineral wool and the hydro-vapor barrier, which will improve the conditions for removing trapped moisture. Secondly, if there are slats under the overlaps, then you can press the tape firmly, the sealing will be more reliable.

The slats are nailed down

Practical advice. When installing the insulation, take measures so that it does not rest against the water vapor barrier. Mineral wool must be fixed in the space between the rafters. This can be done with rope made of synthetic materials, metal profiles or wooden slats. The fact is that mineral wool bends and sags a little over time under the influence of gravity. Unforeseen forces begin to affect the water vapor barrier, it bends, and the sealed joints become depressurized.

Roof insulation

A roll of vapor diffusion membrane is rolled out parallel to the ridge

The overlap between the vapor diffusion membrane sheets is 10-15 cm

Fixing the canvas

Sealing the joints of the vapor diffusion membrane with self-adhesive tape

Organization of the ventilation gap

There are 10 cm gaps in the bars every 2 meters

The membrane is secured with slats

After completing the work, you need to carefully inspect the roof surface again and correct all detected problem areas. Particularly carefully monitor the connection of the water vapor barrier to various pipes and other engineering structures. Experienced builders recommend finishing them with any silicone sealants before fixing the membranes. They will completely fill the seams in masonry building materials and improve the quality of water vapor barrier. And this, as already mentioned, plays a decisive role in the longevity of operation and the heat-saving efficiency of buildings.

Video - Water vapor barrier, insulation, roof waterproofing

There are two fundamental approaches to the technology of laying rolled waterproofing material for waterproofing basement foundations residential buildings, buildings and structures. The first considers the laying of rolled material at the joints of seams and mates in the form of two separate technological operations. Each pairing has at least two degrees of protection.

a) laying the material overlapping; b) laying the material end-to-end.

The second considers the laying of rolled weld-on waterproofing material as a single technological operation. In this case, we have one degree of protection for joints, seams and interfaces, which is extremely undesirable for underground construction due to the lower reliability of the resulting waterproofing membrane from roll materials.

Single-layer waterproofing membrane with one degree of protection in seams and interfaces. Laying rolled waterproofing material with an overlap.

In underground structures, the seams between laid roll materials are subject to shear forces. This is especially typical when there is a load of soil when filling the pit sinuses and there is no or poor quality screen protecting the membrane. Typically, the strength of a weld obtained by fire treatment is quite high.

The adhesion (cohesion) of the glued material to the concrete for tearing off (tearing off the strip) must be at least 2 N/mm (20 kgf/cm). The choice of roll material for waterproofing basements of private houses, industrial buildings, and buildings is made in accordance with the requirements of standards developed for bridges, tunnels and roofs.

Domestic roll fused bitumen-polymer materials that today provide the creation of high-quality waterproofing membranes include Technoelast, Technoelastmost B, Technoelastmost S, Technoelast SOLO, Rubiteks.

A single-layer waterproofing membrane made of rolled waterproofing fused materials is recommended for use in underground construction with a possible water pressure of up to 0.05 MPa (5m). The thickness of the material can be 3-5 mm. In case of higher water pressure, it is recommended to use a two- or three-layer membrane made of fused materials. Moreover, its thickness from several layers reaches 12-15 mm.

For Russia, when designing a waterproofing membrane from roll-fed waterproofing materials, one should be guided not by the level of location groundwater for a given construction site, and the possible water level from the ground level. That is, if the pit has a depth of 5 m, the calculated column of water acting on the waterproofing membrane should be assumed to be 5 m. This is due to the fact that in the spring, when the soil freezes, water penetrates to the contour of the structure from above and creates the maximum possible static pressure.

If this is not taken into account by the design, the structure may float up, the membrane made from rolled waterproofing welded materials may rupture, and cracks may appear in the structures.

Structures laid below the predicted level of groundwater rise should be expected to rise to the design loads according to the formula.

When laying materials, great attention should be paid to preparing the concrete surface. It must be dry and clean. Typically, a concrete substrate with a moisture content of no more than 5% is considered dry. But often when laying waterproofing membranes on massive concrete structures, it is necessary to take into account deep moisture. Most often, moisture measurements are made using a building materials moisture meter, a universal moisture meter MG4U, but you can determine the presence of moisture by laying a plastic film on the surface of the concrete. If moisture does not accumulate or condense underneath it within 2-3 hours, then the concrete surface can be used for the application of rolled waterproofing overlay materials.

All concrete and reinforced concrete substrates must be treated with a primer before laying the surfaced materials. Approximate primer consumption is 0.25-0.5 kg/m². To prepare bitumen, use petroleum construction bitumen, bitumen primer TechnoNIKOL No. 01, bitumen emulsion primer TechnoNIKOL No. 04.

The main advantage of rolled materials is the uniform thickness, which is ensured during their production at the factory, which determines the uniformity of their application throughout the treated area. Thickness finished materials ranges from 0.5 to 5 mm, and the width is up to 1 m.

Certain difficulties also arise when isolating various interfaces, including different types materials. When backfilling a pit or embankment of a structure, the use of special protective measures is required. Before applying the materials, sharp protrusions on the working surfaces should be eliminated so that they do not cause damage to the membrane made of rolled weld-on waterproofing materials during its installation and backfilling with soil. Backfilling operations should begin immediately after installation of the fused-beam membrane. Soil compaction should be 0.90-0.92 of the original.

The surface on which the material is applied must be smooth, clean, dry, without sharp protrusions and depressions, dust, dirt, oils, paint.

Laying of rolled waterproofing fused materials on walls is always done from the bottom up according to the “fish scale” principle. Laying the rolls on top of each other should ensure unhindered drainage of water. Retaining walls, screeds, bitumen-impregnated fiberboards, and polystyrene sheets are used as protective layers before backfilling. The most critical places are interfaces, communication entries and expansion joints.

Laying rolled materials from bottom to top according to the “fish scale” principle

1 - first layer; 2 - second layer; 3 - overlap of sheets.

Installation of a waterproofing membrane at the wall-floor interface of a buried structure (section)

1 - waterproofing key; 2 - protective coating made of polystyrene; 3 - fillet made of cement-sand mortar (Tekhnoruf B60 fillet, interface with vertical surfaces); 4 - waterproofing membrane made of rolled waterproofing fused materials; 5 - concrete or mortar preparation.

1 - floor slab; 2 - protective screed; 3 - waterproofing membrane made of rolled fused waterproofing materials; 4 - concrete or mortar preparation; 5 - primer layer; 6 - mastic coating; 7 - two-layer membrane at the wall-floor junction; 8 - waterproofing membrane made of rolled fused waterproofing materials; 9 - protective coating made of polystyrene.

Input device into a structure made from an external contour waterproofing membrane

1 - concrete structure; 2 - primer for sealant, if required by the project; 3 - sealant (bitumen-polymer sealant TechnoNIKOL No. 42, Sazilast 21 two-component polysulfide curing sealant);
4 - anti-adhesive gasket; 5 - injection of cement-sand mortar at low or high blood pressure(pressure depends on the width and depth of the gap);
6 - waterproofing membrane made of rolled waterproofing fused materials along the outer contour; 7 - additional reinforcement around the sleeve;
8 - possible location of the leak detection system between the membrane and the structure; 9 - sealed seam to ensure water tightness.

A waterproofing membrane made from rolled waterproofing materials will work efficiently if it and its elements are designed and constructed in such a way that they meet two main purposes:

• a) initial operational characteristics;
• b) requirements for durability and operational reliability.

For Russian conditions, one of the most important properties of waterproofing membranes made from rolled waterproofing fused materials is their resistance to temperature changes. The coefficient of thermal expansion of bitumen-based materials is very different from that of concrete.

Bituminous materials heat up quickly, but also cool down quickly. The location of waterproofing membranes made from these materials in an area of ​​active temperature exposure can lead to their failure. As measures that can to a certain extent reduce the negative consequences of temperature exposure on a waterproofing membrane made of rolled waterproofing fused materials, we can recommend the selection of materials resistant to negative temperatures, even if they will not experience this effect during operation (Tekhnoelast, Tekhnoelastmost B, Technoelastmost C). This will increase the cost of the design, but will reduce operating costs.

In addition, it is necessary to calculate the deformation stability of waterproofing membrane coatings of rolled materials when temperatures change. When the air temperature decreases, tensile stresses arise in waterproofing coatings based on organic materials. This is further aggravated by the unequal layer thickness at the seams and joints.

It is difficult to underestimate the importance of such a stage in the construction of a house or other structure as vapor barrier. This term means various ways and means designed to exclude or minimize the penetration of moisture in the form of condensation into structural materials. It is important to determine which side to lay the vapor barrier on, and the tips or instructions below will help with this.

Insulation materials are the most vulnerable to moisture. Under the influence of moisture, the structure of most modern insulation materials is damaged, and as a result, their thermal insulation properties decrease or disappear. However, this is far from the only threat posed by condensate penetration. In a humid and closed environment, fungal organisms, that is, mold, which is completely unnecessary there, begin to actively develop. They negatively affect the reliability and durability of load-bearing structures, especially wooden ones.

Vapor barrier material options

The modern building materials market has a wide range of vapor barrier coatings. They are divided according to many characteristics, primarily by vapor permeability, which is needed to select the location for installing the insulation. Also, vapor barrier materials have a fairly wide price range, which should also be taken into account when choosing a material.

The main types of vapor barrier are:

1. Traditional vapor barrier film;
2. Film with a layer of aluminum foil;
3. Membrane film.

Unfortunately, there is no material that is equally acceptable for any area of ​​vapor barrier, be it a roof, walls, one of the floors, or a foundation. Therefore, it is extremely important to take into account the structure of the materials being coated, the purpose of the insulation and the area of ​​coverage, and based on this, choose the right specific material, as the instructions will tell you.

In addition, it is necessary to take into account the characteristics of each type of vapor barrier. If a vapor barrier film made of polyethylene is installed, it would be correct to leave gaps, because in addition to insulation from steam, the film is completely airtight, so condensation will form in a closed structure without air access.

Features of membranes

Membranes, in addition, are divided into pseudo-diffusion, diffusion and super-diffusion. They differ in vapor permeability coefficient, which is 300 g/m2, 300-1000 g/m2 and more than 1000 g/m2, respectively. Based on this characteristic, the suitability of membranes for insulating certain structures is determined. Pseudo-diffusion practically does not allow moisture to pass through, and is most suitable for vapor barrier of the outer layer under the roof. However, an air cushion is needed between the film and the insulation. And such films are completely unsuitable for insulating facades. The pores of the membrane become clogged with external dust, and condensation begins to remain directly on the material.

The remaining types are more versatile due to their larger pore diameter. This makes it difficult to clog them and allows you to avoid leaving air gaps.

Correct placement of material

A key role in achieving good insulation of structures is played by which side to lay the vapor barrier. The answer to this question also depends on the chosen vapor barrier material:

1. Vapor barrier polyethylene film is laid with either side facing the insulation, but there are special vapor-condensate films with roughness for better evaporation of condensate. In this case, the film is placed with its smooth side facing the insulation. Such details are usually determined by the attached instructions.
2. Laying a vapor barrier from a diffusion membrane, by analogy with a vapor-condensate film, is done with the smooth side facing the insulation.
3. Materials containing energy-saving foil should be correctly mounted with the foil side facing the inside of the room, because it reflects heat.

It is important to consider the following features:

1. Vapor barrier material, whether it is rolled or sheet, is laid only overlapping and secured with special tape that prevents the passage of air in the gaps.
2. Under no circumstances should damage (breaks, cuts) to the insulating material be allowed, even if they were formed during the process or after installation they must be sealed.

DIY vapor barrier

Vapor barrier of a room is a procedure that can be done with your own hands. If you take into account the above rules, correctly determine which side the insulation is laid on, and choose the right material, then even without the help of professional builders, it will be done reliably.

The most indicative would be a do-it-yourself floor vapor barrier. Before installing insulation and vapor barriers, it is strongly recommended to treat underground structures with compounds against wood rot and against insects. This treatment is of particular importance for structures located closest to the ground and foundation. After this, the logs are installed, and the subfloor of the first floor floors is mounted on top of them. This will be the basis on which the floor vapor barrier is laid.

The selected vapor barrier material is laid on top of the subfloor, with an overlap of 15–20 centimeters. It can be secured with nails or a construction stapler, but the most correct would be the previously mentioned adhesive tape. Places that are difficult to reach, abutments to walls and raised areas of floors, require additional treatment with bituminous material, because it is almost impossible to properly lay film in such places. After laying the vapor barrier, the installation of thermal insulation begins. It is important to lay these materials (mineral wool, polystyrene foam and others) close to the joists.

The vapor barrier of the floor, however, does not end there. Moisture can get into the insulation from inside the house from the first floor. Therefore, when insulating, you need to lay another layer of vapor barrier, similar to the bottom layer. Any type of membrane insulation is most suitable for this purpose. This layer is also overlapped. You can confidently lay the main floor on top of it. In this case, you need to leave 1-2 centimeters as a gap.

Conclusion

With the correct choice of side, which insulation is laid to the insulation, as well as the correct choice of the vapor barrier material itself, reliable vapor barrier of the floor will be ensured. And it, in turn, is one of the important components of the overall reliability and durability of buildings.

Laying waterproofing, its features, choice of materials for its implementation

Important features when laying hydro- and vapor barriers must be taken into account when building any structures, otherwise inattention at these stages can lead to disastrous consequences during the operation of the house

Which side to lay the waterproofing film

Proper waterproofing of a building is one of the most difficult and critical stages of construction or renovation.

If the waterproofing material is laid incorrectly, then within six months the residents of the house will be able to observe an unpleasant picture in the form of:

• high room humidity;
• getting the insulation wet, which will very soon collapse from such exposure;
• poor heat retention inside the house due to a wet insulating layer.

To avoid the above problems, it is initially important to lay the waterproofing correctly, namely on the side recommended by the manufacturer. Below we will answer the question of which side to lay the waterproofing under different types building materials and different parts building.

Under metal tiles

Under the layer of metal tiles, the waterproofing film is laid with the markings up, horizontally from the ridge to the eaves, with an overlap of 15 cm. The film should only be attached to the joists or rafters using a stapler. It is important to remember about the film sag, which must be under the metal tile layer (about 2 cm). It will help air circulate freely and protect the film itself from premature destruction.

Waterproofing floors in rooms such as bathrooms and kitchens requires maximum precision in laying the moisture barrier layer. In this case, the waterproofing film is attached with the unmarked side to the insulation.

The roof waterproofing stage begins with laying insulation. Then at him even layer A waterproofing film is spread into the joint. The film is laid with the logo facing up, with the adhesive layer directed towards the insulation. Be sure to take into account the ventilation gap for normal air circulation between materials.

To waterproof walls inside the house, the film is mounted with the logo facing up, with the unmarked surface facing the insulation.

Laying the waterproofing film on the walls outside the house is carried out on the insulation, with the markings facing up. The film is secured with a construction stapler with an overlap of 15-20 cm.

To the ceiling

Waterproofing films are laid with the unmarked side facing the insulation layer or the ceiling.

Properly laid waterproofing is a guarantee of long service life of the insulation. Keep this in mind and take into account the recommendations of the manufacturer of waterproofing films during repairs and/or construction.

Which side to lay the waterproofing film

Which side to lay the waterproofing film on? Proper waterproofing of a building is one of the most difficult and critical stages of construction or repair. If the waterproofing material

Which side is the correct way to lay a vapor barrier in a house?

The tendency to insulate everything has led to the fact that most people absolutely do not understand why a vapor barrier is needed in a house. Well, let's try to find out.

So, the air humidity in any living space is higher than outside - because of this, steam is formed. In the summer, it freely escapes through the ventilation system and a layer of insulation, but in the winter, a phenomenon is observed that people say “the walls are crying.”

Vapor barrier concept

This happens when steam does not find a way out and condensation settles in the walls or on the ceiling. As a result, the walls become damp, mold forms on them, and the thermal insulation material becomes saturated with moisture and completely loses its protective properties. Prolonged contact of walls with moisture will lead to cracks.

To avoid such a situation, when repairing or building a house, it is necessary to add a vapor barrier layer to the insulation to eliminate any possibility of steam or moisture getting into the thermal insulation layer, as well as walls and other structural elements of the house. After all, all walls are susceptible to moisture formation, and not just the insulating layer, since steam accumulates along the entire perimeter of the home, which separates the warm zone from the cold one. This includes basements and roofs, if they are not heated.

Vapor barrier materials

The cheapest and short-lived materials for vapor barrier are glassine or polyethylene. But they have long since become a thing of the past, and modern materials have replaced them:

Roofing membrane options

1. The membrane is perforated. Small holes are pierced in it and moisture comes out through them. The vapor permeability coefficient is very low, so this material is used only as an under-roof vapor barrier for a cold sloping roof. After all, during frost, steam will settle directly on the membrane, which will significantly reduce its vapor permeability.
2. Porous membrane. The structure of this material most closely resembles a filter due to the presence of pores between the fibers. Steam seeps through them. Accordingly, the coefficient of vapor permeability is determined by the size of the pores and the moisture-repellent properties of the walls. But if the environment is heavily polluted, in particular with dust or exhaust gases, then the pores become clogged and the vapor permeability of this material is significantly reduced.
3. Three-layer superdiffusion membranes. Most reliable material, where each layer serves to perform a specific function. This membrane has no holes, so dust or wet sediment will not damage this material. The three-layer membrane is perfect for urban environments and also performs excellent vapor permeability and moisture protection functions.
4. Double-layer film membranes. Used over insulation. This is a relatively inexpensive replacement for a three-layer vapor barrier. The absence of one protective layer slightly impairs the reliability of the membrane; this material is used for internal vapor barrier of roofs and walls.

Tools

Vapor barrier materials are quite easy to damage, which should not be done under any circumstances, since if the film is damaged, moisture will penetrate into the insulation and over time it will completely lose its protective properties.

During installation, wooden slats, sublattices, or a metal, galvanized profile are used. The material is secured with self-tapping screws, staplers or nails.

If the vapor barrier layer is thin, for example, a regular film, then you can use tape; it reliably connects the joints.

Work process

Floor vapor barrier

Performed directly in the premises on the ground floor. This operation is also carried out for rooms where humidity is significantly increased.

First, you need to carry out waterproofing - this is a set of protective measures against the harmful effects of water. Waterproofing is laid on the cement screed. For floors and walls, a coating material is more suitable - a special moisture-resistant substance that is applied in several layers to structural elements to prevent corrosion or other harmful effects of water.

A layer of insulation is laid behind the waterproofing layer, and it is covered with a one-inch thick board. A vapor barrier layer is laid on top of the board.

When the main material is film (perforated, polyethylene), it is secured with double-sided tape so that it does not sag.

Since a vapor barrier is necessary to prevent condensation from getting on the insulation, how to properly lay the material with the smooth side outward, then it will stop any moisture.

The same should be done with a vapor barrier, which is covered with aluminum on top; the shiny side should be in the room to retain moisture, and the rough side should be applied to the insulation.

The vapor barrier is always overlapped. The distance between the joints should be 15 cm. It is glued together with tape or special tape, and then secured with a stapler to the board that is located under it.

The best way to vapor barrier a floor is to use liquid rubber made from bitumen. How does it work? Liquid rubber is applied on top of the boards. When it dries, it becomes an elastic waterproof film that is very well glued to the floor and does not allow moisture to pass through.

Vapor barrier of walls

There are two types - external and internal vapor barrier. The process itself is almost completely similar to the previous one.

For internal vapor barrier, a vapor barrier film is attached along the entire perimeter of the wall using a stapler or galvanized nails. The question often arises of how to properly install a vapor barrier. If the contents of the vapor barrier contain foil, then its shiny edge is located inside the room. When using foam propylene material, the rough side is applied to the wall.

The canvases are laid horizontally, starting from the bottom. The joints must overlap, and then, for reliability, they are glued with tape or mounting tape. Galvanized profiles are mounted on top, on which drywall is then laid. There must be ventilation gaps between the drywall and the vapor barrier.

External vapor barrier is a set of measures to protect insulation from harmful effects external environment, which can come from both outside and inside, through damage to the wall covering.

To protect the insulation from the outside, it is necessary to use a wind-moisture-proof, vapor-permeable membrane, strong enough to protect the walls and insulation from wind and moisture, but with the ability to release steam out of the fiber insulation.

This material is laid starting from the bottom, along the outside of the insulation. The rough structure allows steam to pass through, so it should be laid correctly against the insulation, and the smooth, water-repellent side should remain outside.

They are mounted on a wooden frame with an overlap, there should be at least 15 cm between the joints. And then they are secured with a construction stapler. Wooden slats are installed on top of the covering, which carry the outer skin.

Another feature of the water-repellent material is that the lower edge serves to drain the flowing moisture to the basement drain of the building, otherwise the foundation may sag.

Roof vapor barrier

This is also done both from the outside and from the inside.

If the roof is insulated with a special thermal fiber, then a two-layer vapor-permeable membrane is used to protect against the negative influence of the external environment. The top layer reliably protects the insulation from snow, wind and moisture, as well as in places where the roof is defective. The internal vapor-permeable layer of the membrane allows for unhindered removal of under-roof condensate.

The material is rolled out horizontally relative to the roof slope, and then secured to the rafters using a stapler. In this case, it is necessary to correctly lay the vapor-permeable membrane with the rough side facing the insulation. After all, the smooth side provides a water-repellent effect.

Wooden slats 4-5 cm thick are fixed on top using nails or self-tapping screws. The slats create a ventilation effect, which is necessary to ventilate condensation that forms when steam collides with the cold surface of the roof. Then a lattice of wooden beams is mounted along the slats or, if the type of roof requires it, a solid board deck, onto which the top layer of the roof is attached.

For non-insulated roofing, a three-layer superdiffuse membrane is used. It protects each structural element, as well as the attic itself, from steam and condensation formed by it. In addition, the three-layer membrane retains moisture from negative atmospheric phenomena penetrating through roof damage, such as:

Mounted on wooden slats without taking into account the side. Lay it horizontally with an overlap. They are fixed on top with slats to ensure ventilation, then the roofing condensate will evaporate correctly.

The vapor barrier of the roof from the inside is done using a two-layer film. We must not forget that the smooth side provides protection from moisture, and the rough side retains drops of condensation until they evaporate. Therefore, it is correct to lay such a vapor barrier with the rough side facing the ceilings, the smooth side should go out.

Vapor barrier is great way extend the service life of the external enclosing structures of the house, as well as protect the insulation layer from moisture that occurs through condensation or water that penetrates through damage to the external finishing layer or through damage to the roof.

Which side to lay the vapor barrier and waterproofing towards the insulation, instructions for correct installation materials

What is vapor barrier. What materials to use for vapor barrier. How to lay it correctly, which side. Process description.

Which side to lay waterproofing on?

Often waterproofing is installed water-repellent side in the direction from which moisture can penetrate. For example, roof waterproofing is laid on top of the insulation with a water-repellent layer facing up. And on the floor and walls, the water-repellent layer is directed away from the insulation, while waterproofing can be used both inside and outside the building.

How to determine the water-repellent side for different types of waterproofing:

Which side is the waterproofing placed on the floor?

Depending on which side protection from moisture is needed, the waterproofing spreads:

• water-repellent side down - when laying under moisture-absorbing insulation on concrete or earthen floors;
• water-repellent side up - directly under the screed to protect floors in very wet areas.

Which side to lay waterproofing on walls

The principle of waterproofing walls is the same as that of floors. If you need to protect the insulation or walls from an internal source of moisture, the waterproofing is attached inside with the water-repellent side facing the room. And to protect the walls from the outside, the moisture-repellent layer should be directed towards the street.

Which side is the waterproofing placed on the roof?

The water-repellent side of the roof waterproofing should be directed outward from the insulation. After all, with its help, the insulation is protected from moisture penetrating from the outside - when precipitation or condensation forms under the roofing. The rough side should absorb moisture from the insulation and evaporate it.

Which side to lay waterproofing under metal tiles

Due to its characteristics, metal roofing (made of corrugated sheets, metal tiles) requires special waterproofing - special anti-condensation films. This is the only type of waterproofing that is attached with the fleecy side facing out. It is thanks to the moisture-absorbing outer layer that the metal roof is protected from corrosion - all absorbed moisture quickly drains away without lingering.

Do you need waterproofing on the ceiling?

The ceilings in the rooms are covered only with vapor barrier; waterproofing on the inside of the rooms is not used even in the bathroom or sauna. Otherwise, the interior decoration will regularly get wet - after all, the waterproofing will remove condensation from the insulation into the room.

Which side to lay the waterproofing on: towards the insulation, correctly

How to correctly and which side to the insulation you need to lay waterproofing and waterproofing film: on the floor, ceiling, roof and walls. Answer from construction experts.

One of the most difficult tasks in construction is waterproofing buildings. The main protection of waterproofing is to protect the roof from rain and capillary moisture. It is especially worth paying attention to how to lay the insulation, and make sure which side all the materials are placed.

Waterproofing material is designed to protect not only the building from moisture, but also the insulation, thanks to which it will last much longer.

Waterproofing not only protects the building itself from water penetration inside, but also protects the insulation, which affects its properties. When wet, insulation loses its heat-insulating properties, which can lead to its destruction. Water that penetrates into the premises will also negatively affect the appearance of the building.

First, it is worth understanding that waterproofing and drainage are not mutually exclusive concepts.

Before building a foundation, walls, etc., you need to take care of drainage, especially if the house is located in areas where water accumulates or there is high groundwater.

Secondly, it is worth choosing waterproofing materials based on climatic conditions, as well as depending on the area.

The waterproofing of the building must be thought out at the design stage; if not thought through, it will lead to additional costs that are not comparable to those that will occur during construction and re-installation of all materials.

Waterproofing can be very different: coating, plaster, polymer, penetrating, injection, roll.

Insulation using roll and sheet materials

Pasted waterproofing is sheets or rolls, the base of which is made of moisture-resistant mastics.

Depending on what type of waterproofing is chosen, it must be installed correctly.

Pasted waterproofing consists of rolls or sheets in which special layers of waterproof mastics are applied to the base. The most common and most familiar materials- this is roofing felt, glassine and roofing felt. Based on the fact that these materials are cardboard based, it should be taken into account that they can only be applied to horizontal surfaces.

The adhesive waterproofing must be placed with the side facing the hydrostatic pressure, sandwiched between the protective coating and the structure that is being insulated.

However, this type has a number of significant disadvantages: it is not resistant to rotting, short-lived and poorly resistant to water. It is difficult to lay on the roof; it requires thermal preparation. And in a torrential downpour, the roof may drip, unable to withstand the pressure.

Waterproofing work should be carried out in several stages:

• initially apply a primer;
• the soil layers are dried;
• if necessary, putty is applied and it must be dried;
• paint layers are applied and these are also dried;
• The coating is subjected to heat treatment or exposure.

Emulsion-mastic compositions must be placed hot, for this the following technical requirements must be observed. Bitumen insulation must be heated to 180 degrees. It should be no more than 20 mm thick with an intermediate layer of 1.5 mm.

Scheme of the main surface waterproofing coatings

When applying tar, the temperature range is within 130 degrees plus minus 10 degrees, with the thickness of all coatings being the same as for bitumen. The work must be periodically inspected and measurements taken at the control area and recorded in a log.

Before laying the roof with roll insulation, it is necessary to level the surface; unevenness should not exceed 2 cm.

This type of roll insulation also includes paint insulation, which is optimally suited for vertical surfaces.

Bitumen-polymer modified waterproofing

This type of waterproofing is used for both the top and bottom layers of the roof, as well as for leveling. There are two types: one-sided and two-sided. This type of waterproofing differs from the usual roofing felt in its resistance to rotting due to its non-rotting base. They are produced on the basis of non-woven fabrics, fiberglass and fiberglass, elastic polyester bases.

The advantages of this type of insulation include a high service life, a wide temperature range in which this material can be used: it varies from -25 to +30 degrees. High resistance to hydrostatic pressure, resistance to aggressive environments, low water absorption. High speed of installation due to its simplicity and the ability to lay on uncured concrete.

Before performing work using the method loose laying the surface must be cleaned and dried. There should be no precipitation or puddles at the work site. It is necessary to remove all oil stains and traces of cement; for this, use a sandblasting unit. It is necessary to ensure which side the waterproofing is laid.

Before work, the material is allowed to rest so that it takes on its dimensions.

This type of waterproofing is characterized by a long service life and a wide temperature range.

Tools required for working with roll waterproofing:

• gas torch for welding longitudinal and end overlaps;
• rolling roller, used in case of insufficient flow of bitumen mass from the seam;
• bandage tapes or special strips at least 20 cm wide;
• self-tapping screws or dowel-nails with a fastening pitch of 25 cm.

Waterproofing film

It is used for any construction work and is the most durable and can withstand direct hydraulic pressure. The most durable of all films is perforated and flat.

Perforated film is thick, brown, gray or black, has perforated cells in the form of cones or parallelipids. It is placed on the floor or wall in cells with the side on the protected surface. It is used for both vertical and horizontal insulation, in places of increased water accumulation, for the installation of “green” roofs.

Flat film does not differ in appearance from ordinary garden film, but is much stronger and more resistant to aggressive environments. It is used for moisture protection of walls in the basement, foundations, and comes in black or dark gray.

This film is used when constructing a floor on the ground; in this case, it is placed under a layer of foam-based insulation. When insulating a floor with mineral fibers, the film is placed on the material, then a layer of flooring is laid.

This type of film is used for waterproofing bathtubs, since tiles cannot guarantee impermeability from water, which accumulates in the seams, which manifests itself in dampness of the walls.

Under-roof protection

Under-roof insulation is carried out using a variety of types of waterproofing materials.

The most important tip to remember is how to properly install waterproofing. Be sure to place it glossy side up. Otherwise, condensation will accumulate and drain into the room, which will lead to inevitable re-laying of the material, and this cannot be done without dismantling the entire roof. Therefore, the operation of the house and its final cost depend on which side it is laid.

It is best to fasten waterproofing material under the roof using galvanized nails with a wide head.

If you are placing special materials, you must do this in the following order:

• a film is placed on the heat-insulating material;
• a film is pulled over the ridge of the house or edge with an overlap of at least 20 cm, with the glossy side up;
• We nail the counter-battens and fasten a strip of polymer film on top.

When installing a roof window, place the film on the window frame and secure it. The width of the film placed on the window frame is no more than 5 cm. The joint must be completely sealed. Flexible corner elements are installed to drain water onto the roof.

The under-roof insulation is installed using a stapler or nails with a wide galvanized head. Counter-lattice bars with a cross section of 40 by 25 mm are nailed on top of the film.

Water should not be allowed to drain onto the insulation; additional insulation is required at the intersections with structural elements penetrating inside.

Insulation protection

It can be of two types: simple and with anti-condensation action. In this case, there are polyethylene, polypropylene and non-woven breathable ones. Polyethylene films are used for both vapor barrier and waterproofing.

Non-perforated films are used to protect against water, and perforated films - against steam.

There is a large number modern materials that can protect the insulation, for example, membrane and roofing films, reinforced mesh or special fabric. They must be laid with the right side facing the insulation, otherwise, instead of protection, the insulation will be destroyed.

Diffusion membranes must be laid on the insulation itself, this will save space and reduce unnecessary costs. The strength of membranes is much higher than that of films. We must not forget that membrane materials are one-sided, and which side you place it on will depend normal functioning the entire roof structure and the insulation itself.

There are membrane films with cone-shaped holes, which are located so that steam and water come out rather than being trapped inside.

Place the insulation between the hydro- and vapor barrier, in this case the reflective surface of the vapor barrier, fixed from the inside of the under-roof space, will function well. When using polyethylene or polypropylene films, a gap is needed for ventilation; in this case, install drywall.

You cannot skimp on materials, and it would be good to supervise the workers when it comes to waterproofing.

Ivan, Rostov-on-Don asks a question:

I started building a summer house, but I don’t know which side to put the waterproofing in in certain cases. A neighbor in the area had an accident. In the spring, water began to leak from the ceiling, causing significant damage to the newly completed interior. It is clear that his mistake was precisely in the waterproofing of the roof. So I want to know in advance how to do it right so as not to repeat his mistakes. After all, this may lead to the need to dismantle the roof in the future.

The expert answers:

To answer in detail the question of which side to lay waterproofing on, you need to know what type of waterproofing coating will be chosen in a given case.

Correct installation of adhesive waterproofing

Pasted waterproofing is characterized by the fact that it has on its basis thin layer mastics made from a special composition with increased moisture resistance. Ruberoid, roofing felt and glassine are just such materials. All of them are either rolled or sheet. Since the basis for them is ordinary cardboard, these materials are laid only on a horizontal surface. Otherwise, damage to the integrity of the material is inevitable, which will lead to leakage.

The adhesive waterproofing is clamped between the outer layer of protection and the surface to be insulated. It is placed with the protective (usually smooth) side in the direction from which exposure to moisture is expected. You need to know that when covering the roof, the surface is leveled so that the differences are not more than 2 centimeters.

In the presence of significant advantage Due to its low cost, this type of insulation has a number of disadvantages.

1. Poor rot resistance.
2. Fragility.
3. Insufficient resistance to strong water pressure.
4. Difficult installation on the roof.
5. The need for heat treatment during installation.

These shortcomings can lead to the roof leaking after a while.

Return to contents

Application of waterproofing film

This material has the best strength of all. It can withstand powerful water pressure. It can be used in any construction work on any surface. This film can be either flat or perforated. The perforated material is thicker and darker in color. Perforation cells are made in the form of small cones and parallelepipeds.

Waterproofing should be laid with the honeycomb side on the desired surface. It doesn’t matter whether it’s the floor or the walls, the ceiling or the roof. This film can be used on both vertical and horizontal surfaces. It has become especially popular when installing “green” roofs, as it can withstand large amounts of water.

Flat film is similar to garden polyethylene film, which is used to construct greenhouses. However, unlike it, it is more durable. It comes in black or dark grey. Since this coating is very resistant to aggressive environmental influences, it is used to protect walls in basements and foundations.

This film can be used to create a ground floor. At the same time, it is placed under the foam. If insulation made from polymer fibers is used, a film is first placed on them, and then the floor. In addition, it is a good waterproofing material for swimming pools, fountains, bathtubs and other similar hydraulic structures. This unique material can be placed on any side.

In order for the house to be reliably protected from moisture, it is important not only to select roofing and waterproofing materials, but also to correctly install the roofing pie. In this case, it is worth paying no less attention to the installation of waterproofing than to roofing coverings. In this article we will talk about the installation of waterproofing films and membranes.

Installation of films and membranes

Installation of waterproofing films

[*]In order for air to pass through the ridge, the waterproofing material should not reach it by 40-50 mm.

Ventilation gap when installing waterproofing film

* Note: Perforated film MUST be laid in such a way that the perforation is oriented outward. Otherwise, the action of the film will begin to let moisture into the roof and not release steam from the inside, which will mean the opposite of its purpose. With such “protection” the roof will begin to leak and rot.

Installation of anti-condensation film

• The film is installed in dry weather after installing the roof rafter system and laying insulation.
• The distance between the rafters should not exceed 1.2 m.
• The anti-condensation film is laid out on the rafters with the absorbent surface down. In this case, its lower surface should not touch the insulation.
• Secure with staples of a construction stapler or galvanized nails with a wide head.
• The film is installed from the eaves to the ridge of the roof, overlapping in horizontal stripes. The overlap of the strips horizontally is about 15 cm, vertically - no less than 20 cm.
• The joints of the film should be on the rafters.
• All joints are fastened together using mounting adhesive tape.
• Installation is carried out so that the film is stretched evenly, without folds or creases. There should be a sag of 1-2 cm in the center of the rafter distance. This is necessary to drain condensation from wooden structural elements.
• the distance between the film and the insulation should be 40-60 mm.
• The lower edge of the film should ensure the removal of flowing moisture into the drainage gutter.
• After installation, the film covering is secured using 3x5 cm slats, which are nailed on top along the rafters with galvanized nails. A sheathing that matches the specific roofing system is installed on top of the slats.

* Notes on installing waterproofing films

• During installation, it is necessary to exclude the possibility of moisture draining from the upper surface of the film onto the insulation.
• It is necessary to especially carefully isolate the intersections with penetrating structural elements: stove and fireplace pipes, ventilation ducts, antenna stands, etc. At the intersection point, a trapezoidal incision is made in the film. The top and bottom flaps are retracted and secured to the penetrating part or to the nearest horizontal sheathing member using sealing tape. The side flaps are pulled upward and secured to the penetrating element in a similar manner.
• The adjoining of the material to the roof windows is carried out in accordance with the manufacturer’s (window) instructions.
• In valleys and on inclined hip and hipped roofs the film is first laid along the axis of the ridge or valley.
• Horizontal strips of material on the roof slopes are laid overlapping on top.

Installation of diffusion and superdiffusion membranes

Diffusion and superdiffusion films and membranes will better protect your home from moisture, as they have high vapor permeability.

Membrane design

Installation of volumetric diffusion membranes

• Volumetric membranes are laid parallel to the eaves overhang on a continuous flooring
• Along the top edge, the material is secured with roofing nails (galvanized with a sealing gasket) or staplers.
• The subsequent roll should overlap the attachment points by approximately 7 cm.
• In the overlap area, both rolls are glued together with special glue.
• A self-adhesive sealing tape (usually made of polyurethane foam) is installed on top of the film to provide waterproofing where the counter batten is attached with nails.
• work can be carried out down to an air temperature of -5 C.

*Notes for installing diffusion membranes

Installation of vapor barrier films

Vapor barrier films are attached to the inside of the roof structure, usually on either side (except for films with a layer of foil).

• The film is attached from the inside of the thermal insulation to the load-bearing wooden elements of the roof structure.

Installation of vapor barrier film

*Notes for installing vapor barrier film:

This article provided basic recommendations for the installation of roofing films and membranes. Usually, all work on roofing and its protection is entrusted to professionals, but it will be much easier for you to control the progress of work if you know the main points of installing hydro- and vapor barriers.

Nowadays, metal tiles are often used to decorate the roofs of buildings - the material is reliable and beautiful. However, the durability of any roof and its performance characteristics largely depend on how well the roof space is constructed. Waterproofing a roof under metal tiles is one of the main elements that should not be forgotten during the construction of a building for any purpose.

Why is it so important to have a waterproofing layer under the roof, including under the one that will be covered with metal tiles? Isn't just one enough? finishing material to drain water? So, waterproofing performs several functions, providing reliable protection the roof, the space underneath and the interior of the building.

The main function is protection of all elements located in the under-roof space from moisture. The roof is far from the simplest structure to implement, and its structure is multi-layered. During construction, they are used as rafters and beams, as well as to create sheathing. wooden boards, bars or metal elements. Both materials categorically do not like excess moisture. And waterproofing will provide reliable protection of these elements from it.

Attention! If the roof is insulated, then inside its pie there is both heat-insulating and insulating materials. They also do not like moisture and only a waterproofing layer can provide them with protection from its effects.

Properly installed waterproofing will also allow get rid of the accumulation of condensation moisture in the under-roof space. It is formed due to the temperature difference between the inside of the house and the street and can also affect Negative influence for all materials used in the construction of the roof. Condensation can gradually destroy them and cause leaks and reduce the service life of materials.

On a note! The waterproofing layer will make it somewhat easier to convert the attic into attic room, if such a desire arises among the owners of the house.

Materials used

We found out that waterproofing is the most important element of a roof covered with metal tiles. But what should a high-quality water-protecting layer be like? The requirements for waterproofing are as follows:

• it must have increased fire resistance;
• good steam flow;
• strength and reliability indicators must be high;
• the material should not deteriorate due to sudden temperature changes and should not be afraid of ultraviolet radiation;
• the layer must withstand a certain level of mechanical loads;
• waterproofing should not be susceptible to pest attack or mold development;
• it must also cope well with its main tasks and not cause harm to human health.

Can be used for waterproofing different kinds materials. They all have a lot of differences from each other, including different resistance to light, strength, quality and durability.

In most cases, special roofing films having several layers are used for waterproofing metal tile roofs. There is a reinforcing and absorbent layer. The first provides protection from precipitation, and the second is able to absorb moisture coming from the inside, so that condensation cannot accumulate on the waterproofing and mold will not form. Also, on both sides the material usually has a polyethylene lamination.

This coating has special pores that allow the passage of vapors that form inside the house, but at the same time do not allow moisture coming from outside to spoil the materials from which the roof is made. This feature of the material, called vapor permeability, is especially important if the attic space is converted into an attic and is used as a living space.

Advice! When choosing a material for waterproofing, it is important to pay attention to its service life. It must coincide with the service life of the metal tiles, so that you do not have to dismantle the roof and lay waterproofing again if it fails, and the main roofing material will still be usable. The service life of the special film used under metal tiles is 50 years.

Name	Short description
	A film with low vapor permeability, for which it is important to equip the so-called double-circuit ventilation, which will be located between the roofing and waterproofing materials, as well as between the film and the insulating layer of the roof. The gaps between them should be 3-5 cm. The material is ideal for constructing a cold roof or a roof with a simple design.
	A material that also requires the creation of dual-circuit ventilation. The film is equipped with a moisture-absorbing fleecy layer that perfectly retains excess water. This is a fairly dense material, rough to the touch, durable and resistant to ultraviolet radiation. But the vapor permeability of such a film is low.
	The best material for roof waterproofing, as it has increased vapor barrier performance and does not require dual-circuit ventilation. It is enough to leave gaps between the film itself and the roofing. Installation of this film is simple, it has a long service life. The main disadvantage is the high price.

On a note! Hydrobarriers made on the basis of bitumen and bitumen mastic, you should not use metal tiles for roofing.

Of course, for temporary roofing you can use cheaper film, but for capital construction it is better to take high-quality, albeit expensive, material. There is no need to save money here and it is better to buy a diffusion membrane coating. All indicators of the purchased film are shown on the edge tape that frames the material. The film is produced in rolls 1.5 m wide and 50 m long. The density of the material is about 140 g/m2. A prominent representative of the optimal material for laying under metal tiles is Izospan AM or AS.

Preparing for work

Laying the waterproofing layer requires preparatory work. They include the creation of a rafter system designed according to preliminary calculations, installation of cornice and end boards. Only after this the waterproofing is laid.

Certain tools will be useful for installing waterproofing. These are a tape measure, scissors, a hammer, a marker, a construction stapler, and a screwdriver. You will also need to purchase bars and screws.

Laying process

Installation of the layer can be carried out in two ways: in the first case, the film is laid directly on the rafters in strips parallel to the cornice and attached with a slight sag between the rafters. If you need to leave a ventilation gap between the metal tile and the film, then the film is fixed to the counter-lattice above the rafters. The film can also be mounted perpendicular to the cornice strip. Here it is laid on the finished sheathing and fixed by tension.

Let's look at how the waterproofing layer is installed under metal tiles using a detailed example.

Preparatory work

Step 1. According to the house design, a rafter system is being erected. In this case, it is made of wood, which especially needs protection from moisture, so there is no question of installing waterproofing.

Step 2. The vapor barrier layer is being installed. A special film is attached using construction staples around the perimeter of the building under the rafters and directly to them. Work is carried out in the inner part of the roof. The roll is carefully rolled out and the film is mounted in its intended place.

Step 3. Individual vapor barrier strips must be laid overlapping each other, and all overlaps, as well as the junctions of the material with all structural elements of the roof (pipes, ventilation, etc.) are sealed with adhesive tape.

Step 4. Counter-lattice slats are nailed to the frame on top of the film - it is on them that the entire interior decoration of the attic space will be fixed.

Step 6. Thermal insulation is laid on the vapor barrier between the rafters. The laying is done very tightly in order to reduce the number of cold bridges. This concludes the preparatory work.

Laying the waterproofing layer

After all the preparatory work has been completed, the waterproofing film is installed. In this case, the Tecafol Super membrane is used as a material protecting against moisture.

Step 1. The membrane roll is rolled out on the surface of the insulation along the roof eaves. It is important to lay the material on the correct side, which will be determined by the installation instructions for the selected type of film (usually the material is fixed with that side facing the roofing, where the edge tape has a bright and rich color). The film is laid with a slight sag (about 2 cm). This measure will allow you to get rid of excessive tension and rupture of the material in the event of a sudden temperature change.

Attention! The film should initially be laid on the correct side. You cannot twist or turn it over during installation, as it will lose some of its waterproofing properties.

Step 2. The film is fixed to the wooden rafters using a construction stapler. Instead, you can use nails with a wide head.

Step 3. Next, the second strip of waterproofing is spread. It is laid with an overlap on the first one (15 cm). If the angle of inclination of the slope does not exceed 30 degrees, then the overlap between the individual layers should not be less than 25 cm. The joints can be additionally taped with double-sided adhesive tape.

Step 4. The second strip of the waterproofing membrane is fixed. Thus, the film covers the entire thermal insulation material. In places where pipes, hatches and other structural elements are located, it is necessary to securely fix the material. It is also important to remember that the waterproofing layer is not brought to the ridge of the roof - there should be a ventilation gap of 5 cm. It will be closed with a ridge strip.

Step 5. Along the rafters, directly through the waterproofing film, sheathing bars with a cross-section of 4x5 cm are attached using self-tapping screws. They will additionally fix the film on the rafters.

Step 6. Counter-lattice bars are attached across the sheathing bars in increments of 35 cm - it must correspond to the pitch of the metal tiles. Next, the tiles themselves are installed directly.

It is worth remembering that a gap of 5 cm must be maintained between the tiles and the waterproofing. Otherwise, the required air circulation will not be ensured. There may be no gap above the insulation if a high-quality diffuse membrane is used.

Video - Installation of a hydraulic barrier

Rules for installing hydrobarrier film

When working with waterproofing, it is important to remember several installation rules:

Cold roofs – do you need waterproofing?

The answer to this question will be unequivocal - a waterproofing layer is needed in any case. But since in this case there will be no insulation in the roofing pie and will be provided good ventilation materials, then you can use roofing felt or glassine, which will be cheaper than expensive film. But in this case, it is necessary to form a ventilation gap between the roofing felt and the metal tile.

Waterproofing is a very important layer in the roofing pie of a roof covered with metal tiles. You should not neglect it, so that later there will be no problems with leaks or a reduction in the service life of the materials used to create the roof.

Video - Installation of metal roofing

When installing a roof, the most important issue is waterproofing. It protects the wooden parts of the roof from rain and melt water. Prevents the destructive effects of condensation under the roof space. Provides reliable ventilation and protection of insulating materials from getting wet.

In addition, the waterproofing layer serves as protection against wind. The penetration of cold air underneath significantly increases the cost of heating.

With the development of construction technologies, the roofs of private buildings have changed significantly. New ones have appeared roofing materials, which require other water protection technologies. However, along with modern technologies, there are still cheaper materials for roof waterproofing.

There are two commonly used materials:

• Waterproofing with roofing felt
• polyethylene, reinforced with hydrobarrier

The traditional material for protecting wooden roof structures was roofing felt. This is cardboard impregnated with bitumen, which was attached to the rafters with an overlap of adjacent strips of 10-12 cm. To protect the joints from moisture penetration, they were coated with molten bitumen.

Laying on the roof is carried out by at least 3 workers (two on the roof and one below). Roofing felt is attached to the roofing frame with nails with wide galvanized heads. Wavy slate was laid on top. Thanks to the waves, the slate was ventilated, which prevented the accumulation of moisture under it.

It was a simple and very affordable roofing method that can still be found today. However, this method has a number of disadvantages that significantly affect the service life of the supporting roof frame.

The basis of roofing felt is paper, which in itself significantly reduces its service life when exposed to moisture. The joints of bitumen strips crack after temperature changes after 4-5 years and begin to let moisture through. This is caused by the aging of bitumen, as a result of which intermolecular bonds are destroyed.

When installed on rafters, bituminous roofing felt can easily tear from a slight load. In addition, the roll of this waterproofing is not light in weight, which also makes it difficult to install at height.

Using a hydrobarrier made of reinforced polyethylene film refers to modern technologies. It would not be entirely correct to call this material a film, because it has micro-holes for ventilation. It is more of a membrane than a film. With a small thickness, this material has high strength and low weight.

It is important to know! When laying a hydrobarrier, it is necessary to consider which side to mount the strips of material on the rafters.

The film should be laid on the rafters with the side without inscriptions or in accordance with the instructions that come with the kit. Often the installation sides are indicated on the hydrobarrier. In this case, condensation will not be able to leak out pos. If you mix it up, the water will pass through the membrane onto the thermal insulation. Wet mineral wool will lose its thermal insulation properties.

Laying steam and waterproofing under metal tiles or corrugated sheets

Waterproofing a roof under corrugated sheets or metal tiles requires technology. Only in this case is their service life of 50 years guaranteed.

The installation technology is as follows: laying the first strip of the hydrobarrier begins from the bottom of the roof. The roll is rolled out across the rafters and secured to them with staples or galvanized nails with a wide head.

The next strip is laid with an overlap of 10-15 cm on the previous one and is also attached to the rafters. The joints between two sheets in places of vertical joining are fastened with wide butyl rubber tape. Two sheets are fixed with galvanized nails to the rafters by fastening a counter batten with a width of 20-40 mm

It is important to know! There is no need to install a hydraulic barrier under tension. It is recommended to attach the film between the rafters with a sag of no more than 20 mm.

Counter battens provide a technological gap to ventilate the space between the corrugated sheet and the waterproofing. When the installation of waterproofing on the roof is completed, sheathing is installed to secure the corrugated sheet or. Reiki wooden sheathing with a cross section of 20 x 40 mm, fastened with nails in a direction perpendicular to the rafters.

An attic roof or the roof of any other building requires a 50 cm fastening step for the slats. All counter slats and sheathing beams are first treated with an antiseptic solution. It prevents the formation of fungi and protects the tree from insects. After installing the slats, you can install the corrugated sheet.

Particular attention should be paid to waterproofing around chimney pipes, ventilation and air ducts. According to the technology, a polyethylene membrane is glued to the chimney to prevent rainwater and condensation from getting under the roof. Butyl rubber double-sided tape is used as an adhesive material. The overlap should be at least 10-15 cm.

To further protect the waterproofing around the chimney from overheating, it is recommended to lay a layer of thermal insulation between the brickwork and the asbestos pipe. It is also worth noting that the waterproofing membrane can withstand heating up to 120 degrees C, and double-sided tape is resistant to temperatures of + 70 degrees.

Proper waterproofing of a building is one of the most difficult and critical stages of construction or renovation.

If the waterproofing material is laid incorrectly, then within six months the residents of the house will be able to observe an unpleasant picture in the form of:

• high room humidity;
• getting the insulation wet, which will very soon collapse from such exposure;
• poor heat retention inside the house due to a wet insulating layer.

To avoid the above problems, it is initially important to lay the waterproofing correctly, namely on the side recommended by the manufacturer. Below we will answer the question of which side to lay waterproofing under different types of building materials and in different parts of the building.

Under metal tiles

Under the layer of metal tiles, the waterproofing film is laid with the markings up, horizontally from the ridge to the eaves, with an overlap of 15 cm. The film should only be attached to the joists or rafters using a stapler. It is important to remember about the film sag, which must be under the metal tile layer (about 2 cm). It will help air circulate freely and protect the film itself from premature destruction.

On the floor

Waterproofing floors in rooms such as bathrooms and kitchens requires maximum precision in laying the moisture barrier layer. In this case, the waterproofing film is attached with the unmarked side to the insulation.

On the roof

The roof waterproofing stage begins with laying insulation. Then a waterproofing film is spread over it in an even layer at the joint. The film is laid with the logo facing up, with the adhesive layer directed towards the insulation. Be sure to take into account the ventilation gap for normal air circulation between materials.

On the walls

To waterproof walls inside the house, the film is mounted with the logo facing up, with the unmarked surface facing the insulation.

Laying the waterproofing film on the walls outside the house is carried out on the insulation, with the markings facing up. The film is secured with a construction stapler with an overlap of 15-20 cm.

To the ceiling

Waterproofing films are laid with the unmarked side facing the insulation layer or the ceiling.

Properly laid waterproofing is a guarantee of long service life of the insulation. Keep this in mind and take into account the recommendations of the manufacturer of waterproofing films during repairs and/or construction.