Steam waterproofing: what is it and what is it used for?

Applications

Waterproofing film is often used during the construction of summer cottages, wooden cottages, houses and baths. Also common is the waterproofing of the foundation with a film.

Foundation waterproofing

In this case, the film for waterproofing the foundation performs several functions at once:

• Main waterproofing layer. For this, diffusion films are used that do not allow moisture to pass through.
• Auxiliary waterproofing layer. It is created using polyethylene. A waterproofing film for the foundation is placed between the screed and insulation or between the main waterproofing and the ground. In some cases, it is laid under concrete. Polyethylene is also used as the main waterproofing, as it is resistant to sudden changes in temperature and high humidity.

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Types of gluing waterproofing

Floor waterproofing

Waterproofing is used to protect the floor from water vapor. It is used both in private houses and in apartments. The floor waterproofing film creates a special coating that protects the screed from moisture and fumes from the floor slabs.

The material is overlapped. For greater reliability, it is welded using a construction hair dryer. The floor waterproofing film is laid in one layer. After that, the screed and reinforcement of the floor are made. When the surface is completely hardened, the protruding membrane waterproofing is trimmed.

Roof waterproofing

If you do not take care of the waterproofing of the roof, it will lead to its leakage. High humidity accelerates the metal corrosion process, and the roof is destroyed much faster. A special film is used to waterproof the roof. It is located under the roof. This provides a good level of ventilation in the under-roof cake. Waterproofing is used for insulated and non-insulated roofs.

The material is attached to the rafters. However, it should not touch the insulation. There should be a small gap less than one and a half meters between it and the insulation. Special slats and crate are stuffed on top. The waterproofing should not sag too much.

It is necessary to place the waterproofing in this way so that the film covers the gable and cornice overhangs. In this case, the lower canvas is fixed to the cornice.

Wrapping waterproofing materials

Reinforced propylene film for waterproofing

The range of polymer films for waterproofing concrete screed and foundations allows you to choose the most optimal option, which combines the main characteristics of the material and its practical application. The most common types of plastic films:

• polyethylene;
• polypropylene;
• polyvinyl chloride;
• made of synthetic rubber.

The thickness of the film web ranges from 200 microns to 1.5-2 mm, most builders advise choosing a polyethylene or polyvinyl chloride (PVC) film before buying a waterproofing material, leaving roofing material among outdated materials. Polyethylene and polyvinyl chloride (PVC) films are able to withstand tough operating conditions for more than a dozen years.

The main advantages of the film for waterproofing the floor should be highlighted:

• high strength and resistance to weathering, especially when using a multilayer film reinforced with lavsan or fiberglass mesh;
• extended operating temperature range (up to 100 ° С), which allows using the film when installing heated floors;
• extensibility and elasticity, no breaks under dynamic impact;
• chemical resistance, lack of reaction to the penetration of aggressive substances.

High density PVC film

The main disadvantage is the likelihood of accidental puncturing of the film with a carelessly prepared bulk base, when sharp edges of gravel or gravel can damage the film covering, or the possibility of damaging the film layer during further installation of the floor covering using nails and self-tapping screws.

After that, it is necessary to impregnate the surface of the concrete screed with a special primer, which will strengthen its structure, stop dust formation and enhance the waterproofing properties of the coating. Before waterproofing the old coating, the concrete surface is cleaned and leveled, the cracks are examined and embroidered, they are filled with mortar or mastic, the protrusions are removed with abrasive devices. The application of a primer that penetrates all micropores will help smooth out minor surface imperfections.

Polyethylene film withstands deformation loads well

When installing a floor with a heat-insulating layer, the film is placed under the heat-insulating material and on top of it. In the event that the roll width is not enough to cover the room, the film canvases are laid with an overlap of 20 cm and glued with mounting tape. The film is laid on a cleaned and leveled surface with output to the walls 10-15 cm higher than the intended final floor covering.

To achieve the maximum effect, film waterproofing can be laid in two or three layers, in each layer shifting the location of the seams relative to each other. The use of a film waterproofing in a concrete screed completely prevents the loss of cement laitance and contributes to the formation of a strong concrete structure, since the ripening of concrete must take place in conditions with a certain degree of humidity.

Which side to put the vapor barrier

After the end of the installation of the insulation, vapor barrier work is carried out. Surprisingly, not all builders know which side to lay the vapor barrier film on to the insulation. In this situation, what can we say about “home craftsmen”? There is a general rule - the film is always laid with the smooth side to the insulation layer, rough - inside the room (attic) or on the street.

But you don't have to bother at all - large manufacturers always supply each roll with instructions. And to make it clear where which side is, they put pictograms. The problem arises only if the film has already been cut from the roll and the instruction has fallen out. But here there is a simple solution: take a picture of the instruction from another similar roll with a smartphone.

How to distinguish the inside from the outside

Experienced professionals use other tips:

• the outside is fleecy, the inside is smooth. Easily identified by tactile, touch;
• with different colors of the sides, the lighter one fits into the insulation;
• when unrolling the roll, the inner side always faces the floor;
• the logo is always at the top;
• foil materials are stacked with foil towards themselves.

If there are no markings on the roll at all, then this is a vapor barrier film, not a membrane. It does not matter which side it is laid on, since it creates a barrier for steam in both directions in the same way.

How to check which film you purchased

When buying several types of film, sometimes it becomes necessary to find out what type it belongs to. For this, a piece of material is cut off, two glasses are taken (two circles).Boiling water is poured into one. The second glass is placed on the first, with hot water, previously covered with foil. If condensation does not appear on the walls, turn the film over and put the glass back.

A dry surface indicates type B - the classic type of vapor barrier. If the walls of the container are wet only once - type A, one-sided membrane. The appearance of condensation twice indicates that the film belongs to waterproofing materials and has nothing to do with vapor barrier.

Features of laying specific vapor barrier materials

Above are considered theoretical recommendations for the device of vapor protection. Many site visitors are interested in which side to put the vapor barrier of different classes or specific manufacturers:

• "Izospan AM" - is laid with the brown (dark) side outward, white to the insulation;
• "Izospan V" - the smooth side should fit snugly to the insulation, the rough coating should look inside the room;
• plastic wrap is stacked on either side;
• foil-clad reflective vapor barrier ("Penofol") is mounted with the metallized side inside the room (baths, steam rooms, saunas);
• the membranes are laid in accordance with the pictogram printed on their seamy side;
• polypropylene with a one-sided polypropylene lavsan coating with the smooth side is stacked to the insulation, wicker - inside the room;
• foil films in rooms with a standard temperature regime are laid with the metallized side to the insulation.

What happens if you put it on the wrong side

Among experts to this day there is no single point of view on the processes taking place inside the insulation when laying the vapor barrier material on the wrong side.

Some believe that condensation will begin to form not outside the film, but in the insulation, causing destructive processes in it, others - nothing terrible has happened and it is not worth running to redo the thermal insulation carried out if a mistake was made.

There is generally an original explanation for the rough side - this is the result of joining two strips of vapor barrier film during the production process. It is easier to glue to such a surface, and it costs money to additionally grind the other side. To explain to buyers such a technological technique, a fairy tale about different sides of the film with different functions was invented.

If we take anti-condensation protection as a basis, then those who claim that nothing terrible will happen are right. But here the parties in dispute are missing an important point. The film is called windproof. And here there is a very big difference in how it is laid.

To make it easier to understand what we are talking about, you need to conduct a simple experiment: take a fabric with a pile on one side and alternately on each side, putting it tightly to your mouth, blow through it. There will be practically no resistance from the smooth side, since the villi flutter freely in the wind. From the side of the pile, everything is not so simple. You will have to make an effort, since the villi, pressing against the fabric, clog the pores through which air passes.

A simple experiment shows that it is still worth following the recommendations of the manufacturers.

Roof and wall vapor barrier. Where is it installed and why is it needed?

Let's consider a different situation. Steam has entered the structure and moves outward through the layers. Passed through the first layer, the second ... and then it turned out that the third layer is no longer so vapor-permeable as the previous one.

As a result, steam trapped in the wall or roof does not have time to leave it, and a new "portion" is already supporting it from behind. As a result, before the third layer, the vapor concentration (more precisely, saturation) begins to grow.

Remember what I said earlier? Steam moves from warm to cold. Therefore, in the region of the third layer, when the steam saturation reaches a critical value, then at a certain temperature at this point, the steam will begin to condense into real water. That is, we got a "dew point" inside the wall. For example, at the border of the second and third layers.

There was an obstacle in the way of the steam. Steam saturation has increased and condensation is likely to form

This is what is often observed by people whose house is sewn up from the outside with something that has poor vapor permeability, for example plywood or OSB or DSP, but there is no vapor barrier inside or it is made of poor quality. Rivers of condensate flow along the inner side of the outer skin, and the cotton wool adjacent to it is all wet.

Steam easily enters the wall or roof and "slips through" the insulation, which, as a rule, has excellent vapor permeability. But then it "rests" on the outside material with poor penetration, and as a result, a dew point forms inside the wall, right in front of the obstacle in the path of steam.

There are two ways out of this situation.

1. It is long and painful to select the materials of the "cake" so that the dew point does not end up inside the wall under any circumstances. The task is possible, but difficult, given that in reality, the processes are not as simple as I am describing now.
2. Install a vapor barrier from the inside and make it as tight as possible.

It is along the second path that they go in the west, making an airtight obstacle on the way of steam. After all, if you do not let steam into the wall at all, then it will never reach the saturation that will lead to condensation. And then you can not rack your brains over what materials to use in the "pie" itself, from the point of view of the vapor permeability of the layers.

Moreover, the most popular material for this "they have" is ordinary polyethylene 200 microns. Which is inexpensive and has the highest resistance to vapor permeation, after aluminum foil. Foil would be even better, but it's tough to work with.

In addition, I pay special attention to the word sealed. In the west, when installing a vapor barrier, all joints of the film are carefully glued. All openings from the wiring of communications - pipes, wires through the vapor barrier, are also carefully sealed

The installation of an overlapping vapor barrier, popular in Russia, without gluing the joints, can give insufficient tightness and, as a result, you will get the same condensate.

Vapor barrier does not let steam into the wall and, accordingly, the likelihood of getting enough steam for condensation is greatly reduced

Non-glued joints and other potential holes in the vapor barrier can cause a wet wall or roof, even if the vapor barrier itself is present.

I would also like to note that the mode of operation at home is important here. Summer cottages, in which you visit more or less regularly only from May to September, and maybe several times in the off-season, and the rest of the time the house is standing without heating, can forgive you some of the flaws of vapor barrier.

But a house for permanent residence, with constant heating - does not forgive mistakes. The greater the difference between the external "minus" and the internal "plus" in the house - the more steam will enter the external structures. And the more likely it is to get condensation inside these structures. Moreover, the amount of condensate in the end can amount to tens of liters.

Differences from other species

On the market of modern building steam-waterproofing materials, new types are constantly appearing for the protection of building structures. This is due to the steady development of the chemical industry, which is constantly improving the insulation properties.

Unlike other materials, waterproofing films are supplied in rolls, which makes it easier to correctly measure the required amount of material. This thin and lightweight coating is very easy to install. Self-adhesive tape is the easiest to use.

In addition to protecting against moisture, a vapor-waterproofing film protects the foundation from chemicals contained in groundwater

This is especially important, since even the floor and walls made of concrete without reliable protection from moisture will begin to crack and collapse, not to mention the wooden base, which will undergo rapid decay.

In addition, we must not forget that for the reinforcement of concrete floors and walls, steel rods and wires are used, which are susceptible to corrosion in a humid environment.

Installation features

The filling of the floor consists of several layers, which include logs, waterproofing material, a strip of insulation, a preliminary floor, a vapor barrier and an insulating spray. The filling is completed with a top coat. Before this, the vapor barrier must be prepared in advance. If the building is being built from scratch, then there will be no difficulties with this. Before flooring, pre-floor boards are treated with a disinfectant. This is followed by a vapor barrier material. It is recommended to cover it with a protective layer against moisture. If the house is erected, then the following work is carried out:

1. First, a major overhaul is done. For this, old flooring and other building structures are removed.
2. Then the lags and the rough coating are checked for strength. If they are not strong enough and rotted, then they are replaced with new ones.
3. The next step is to remove all unnecessary garbage. Small specks are removed with a vacuum cleaner.

The vapor barrier is placed on a flat floor. Before installation, you need to find out which side it should be installed on. If an ordinary polyethylene film is used, then you do not need to determine the side. When Izospan is used for flooring, it must be laid with the light side to the insulation.

Read also: the correct installation of Izospan to the insulation.
Thanks to vapor barrier, your home will always have a favorable and comfortable microclimate

To carry out work with a vapor barrier, you will need tape. With its help, strips of individual layers of the coating are combined. This must be done in order to increase the strength of the vapor barrier layer. Individual sections of the material are overlapped. When installing a vapor barrier, no special knowledge is required. The material must be rolled out on the floor and secured with small nails. It is easier to use adhesive tape for this purpose.

Particularly shaped floor areas are additionally treated with a bitumen-based coating agent. In difficult places, it is difficult and problematic to correctly fix the vapor barrier flooring. Insulation is laid on top of the vapor barrier layer. It is used if the protective coating is used not only inside, but also outside. For the insulating layer, mineral wool, polystyrene or expanded polystyrene are used. These materials are placed close to the logs to avoid the formation of holes through which cold will subsequently penetrate.

Vapor barrier is an important step in floor installation. This material should not be neglected or waterproofing spray should be used instead. Thanks to the vapor barrier, a favorable and comfortable indoor climate is formed.

More details about why you need a vapor barrier:

Types of waterproofing

Floor waterproofing is the process of applying protective materials to form an impermeable layer.

Depending on the application technology, this procedure can be divided into several types:

1. Coating room. Ideal for concrete subfloors. Arrangement technology involves the application of solutions to surfaces that need to be protected. It is relatively rare for horizontal bases.
2. Okalechnaya. This type of waterproofing is the most common and versatile. It is used not only in the construction of floors, but also to protect walls. This approach involves gluing roll-up waterproofing materials (plastic wrap, etc.) to the substrate using special adhesives.
3. Tough. Waterproofing of this type involves the use of special plasters. Apply them in thin layers on rough surfaces. This approach is rarely used, since it is the most difficult and time consuming.

Using a vapor barrier

Inside any room there is a certain microclimate, which is ensured by the correct waterproofing for the floor. In the residential building, food is prepared, floors are washed, and showers are used.Due to these actions, a large volume of steam is generated in the air, which goes beyond the boundaries of the walls of the room. It intensely affects all elements of the building, and condensation drops settle on the walls, ceiling and inside the floor.

To protect floors from moisture, it is necessary to use vapor barrier materials.

Moisture is absorbed into all materials used to build a home. Condensation ends up inside the wood, penetrates into the insulating layer and lowers the performance of the manufactories used, leading to their destruction. Vapor barrier is needed for rooms located on the ground floor under the basement or above the ground. In such a building, the floors are subject to increased humidity. Vapor barriers are placed to reduce the level of water entering the floors. At the same time, the movement of air in the room does not decrease at all, and its jets go outside, allowing the building to "breathe".

Vapor barrier is essential for timber buildings. It is also used for concrete structures.

The vapor barrier material should be laid as follows:

• the vapor barrier is fixed to the floor;
• followed by a heater;
• then a second layer of vapor barrier is applied;
• after that, the final floor is laid.

The second layer of vapor control is important because it creates a barrier to wet steam from the building. The foil is installed in such a way that the heat-ventilation gap between the finished flooring and the vapor barrier is observed. The strips of film are glued together using tape or collecting tape.

Read more about vapor barrier in this video:

> Waterproofing material is needed to prevent moisture from entering the building from the street. If water gets into the insulation, the thermal flooring ceases to store heat. This characteristic will be noticeable in winter, when the water inside the floor is converted into ice crystals. The floor becomes colder from this and it will be uncomfortable to live in the building. To prevent this from happening, a layer of steam-waterproofing film for the floor is installed.

The moisture barrier is placed inside the concrete floor. It is needed to protect the materials that are included in the structure of the diffusion base, and protects the floor filling from moisture protruding inside the room (for example, from condensation resulting from cooking and other activities accompanied by the release of moisture and steam). The main differences between materials:

1. Insulations made from a waterproofing coating do not allow moisture, but they can allow evaporation to pass.
2. Steam and moisture insulation helps to retain moisture and steam.
3. The vapor barrier does not have a membrane structure.

To maintain a comfortable temperature in the house, it is necessary to install a layer of steam-waterproofing film

It should be borne in mind that not all waterproofing materials are considered vapor-permeable.

Types of vapor barrier films

Most often, polypropylene and polyethylene films, liquid rubber and diffuse membranes are used as vapor waterproofing. Previously, roofing material and other materials were used. Benefits of using polyethylene film:

1. This is the cheapest available material that is used for a vapor barrier floor membrane.
2. It can be used for installation inside floor filling. Care should be taken when working so that the film does not accidentally break.
3. Some types of materials are perforated.

It is better to use a material with perforation for laying a waterproofing layer, and without it - for a vapor barrier. This is because there are small holes in the material. Whichever film is used, a fan gap must be made for it. It still has to be done, so many do not think about the presence of perforation.

Now you can choose products that have better properties than plain polyethylene. The material has an aluminum reflective layer.The coating has good performance as a vapor barrier and is used in buildings where high humidity is observed.

More about DIY vapor barrier:

> When the humidity level in the room drops, the film dries up and is ready to absorb condensation and vapors again. When laying the material, it is taken into account that the anti-condensate and the absorbing layer must be turned in the opposite direction from the insulation. There is a small ventilation space between the insulating product and the vapor barrier layer.

Diffuse membranes are the most expensive type of vapor barrier. Such material is able to "breathe" and protects the room from moisture. Features of double-sided and single-sided membrane materials:

When using a one-sided type of flooring, it is important to keep track of which side it will face towards the insulation.
Double-sided flooring can be laid as you like.

Membranes have different vapor permeability data. They are made of non-woven synthetic material in several rows. When installing them, there is no need to leave an opening for ventilation. Among modern membranes, there are "intelligent" ones.

For the room to "breathe" it is necessary to use diffuse membranes

They combine several properties:

1. They are used as a vapor barrier that guarantees good waterproofing.
2. They are heat-insulating flooring.
3. They can adjust the steam level taking into account the ambient temperature.

Liquid rubber is rarely used. It is mainly used for concrete structures. It is represented by a polymer-bitumen composition, which is made on the basis of water. Rubber can be applied effortlessly. It is enough to spray it on the base of the floor, creating a durable, seamless coating.

Liquid rubber after flooring resembles a carpet. After polymerization, it will not be able to pass any elements through itself. Usually such rubber is applied automatically or manually. The manual method is used for small spaces.

In this video about floor insulation above the basement:

2> How to choose a suitable hydro-vapor barrier?

In the matter of choosing any insulating material, the value of the structure that is planned to be provided with this protection increases. That is, to begin with, the threats to the place of application are determined, and then a hydro-vapor barrier film is purchased. How to choose this material is not an easy question; several points should be taken into account in it. First, you need to determine the origin of the membrane itself. This is usually polyethylene. It is advisable to choose a perforated film, as it is the most durable. With skillful installation, it can provide a durable and effective barrier against moisture and wind.

If tensile strength is not a fundamental criterion, then a flat hydro-vapor barrier film may also be suitable. The price in this case will be low - a roll can be purchased for 1000-1200 rubles. If a reinforced film with a metal layer is purchased, then you should be ready to pay 2000-3000 rubles for it. But with its help, you can effectively provide not only functional insulation, but also durable.

Waterproofing of interfloor ceilings

The material should be laid between the ceiling finish and its rough surface, as well as on the floor beams over the insulation. In this case, an increased gap of up to 20 cm is also made. To ensure the tightness of the barrier, the waterproofing film for the floor is additionally fastened with a special tape. This material is also supplied by the insulator manufacturers and serves as a connecting element.

It is important to note that if the rooms connected by the insulated interfloor floor have different temperature regimes, then it is necessary to select an insulating material with extended functionality. So, in addition to hydro and vapor barrier, it is necessary to provide for the ability of the barrier to reflect heat fluxes.

For example, a waterproofing film that is planned to be laid in the attic or attic should have similar qualities.