Ensuring a reliable level of vapor barrier in the house is the key to maintaining a stable level of air humidity in relation to the temperature outside. Vapor barrier, unlike insulation, does not easily maintain temperature, but protects the room from exposure to steam and condensation. Many people, when they start installing insulation and vapor barriers, wonder which side to lay the vapor barrier so that it works properly.
The question of which side to lay thermal insulation correctly is very important when preparing work. To understand which side you need to lay the vapor barrier film on the surface, evaluate the entire process of laying the walls, including the installation of insulation. And only then will it be clear which side, where, what needs to be put.
General description of the vapor barrier process
Prepare the base so that it is dry and clean by first coating it with primer. Metal surface should be cleaned of fat. A vapor barrier must be installed on the roof immediately.
On the floor and walls lay the insulation first, then waterproofing, and only then - vapor barrier material, while the film should not be stretched too tightly and should not hang down.
Vapor barrier has the following advantages:
- moisture evaporates faster;
- regulation of the room microclimate along with insulation;
- protection against fungi and mold;
- increasing the service life of building materials.
Installation of vapor barrier materials is carried out in accordance with certain rules. To protect the insulation, vapor barrier material must be placed on inside the room between the thermal insulation layer and internal lining. Also correct styling vapor barrier depends on what material you use.
So, the principle of vapor barrier operation is as follows:
To install a vapor barrier, regardless of the material used, materials such as:
- wooden laths;
- metallic profile;
- construction stapler;
- self-tapping screws;
- metal scissors;
- double-sided tape;
- regular or construction tape.
Classification of vapor barrier materials
The material used for vapor barrier must be durable, have low thermal conductivity and be fire resistant. Universal material for this purpose no, materials such as are used for vapor barrier:
Vapor barrier technology
The algorithm for installing a vapor barrier looks like this:
How to properly install vapor barrier on the ceiling
The ceiling, roof, floor and walls are subject to vapor barrier. Let's start by describing the process of laying vapor barrier materials on the ceiling.
The ceiling needs a vapor barrier due to protection from negative influences water vapor that is formed due to high humidity in room. Household needs such as washing, bathing, cleaning, cooking and much more contribute to an increase in indoor humidity.
The warm air released as a result of these processes goes up and wants to go outside, but runs into the ceiling. A vapor barrier will increase the service life of roofing materials; it will also minimize the likelihood of mold and mildew in the attic. In addition, the ceiling will become more fire resistant.
To lay a vapor barrier on the ceiling, you need rolled material attach to draft ceiling surface and press metal profile or lathing. When you start rolling out the rolls, stripes will appear, butt them together with an overlap of 10–15 cm. To seal the joints, use special self-adhesive tapes.
How to perform a vapor barrier on the floor, roof and walls
It is necessary to isolate the floor from steam, first of all, on the first floors above basements, as well as in baths and saunas. The material is laid after installing the insulation and waterproofing material. Film needed don't pull too hard, but also not to allow it to sag. Then overlap it double-sided tape or special staples.
Please note that the vapor barrier must be laid in two layers, with the bottom and outside insulation, as well as on top of it.
For vapor barriers in large rooms, you need to use liquid rubber made from bitumen. It is applied manually or using a compressor. When it dries, an elastic film of rubber appears in its place, impervious to moisture.
And as a vapor barrier for roofing, it is best to use double-sided diffuse membrane. It should be installed with internal and outside, the membrane must be placed on the heat-insulating material itself without gaps. Bitumen can also be used, which is laid in rolls on top of the roof and secured with counter battens.
Equipping walls with vapor barriers is largely similar. The material must be attached to the wall along its perimeter with a stapler, and each panel must overlap the other by 15 cm; they must be glued together with construction tape. Thin slats are laid on top.
Sheet material is mounted on a frame made of metal or wood. The barrier is secured with self-tapping screws, and the joints are sealed with adhesive tape. On the outside, thermal insulation works before installing the insulation, creating together with it subsequently three-layer protection system.
So, as you can see, installing a vapor barrier is not as difficult as it might initially seem. Thanks to it, you will protect your room from moisture and extend its service life. building materials.
During construction country house or private bath important stage is thermal insulation of various surfaces. In addition, the insulation itself needs high-quality and reliable vapor barrier protection. To prevent negative impact external factors and the formation of condensation on the thermal insulator, any homeowner should have a general understanding of how to properly install a vapor barrier to ensure the long life of the entire structure.
The most popular for their performance characteristics are breathable multilayer membranes, which are designed to create reliable vapor barrier protection.
They consist of three layers, each of which performs important function. The first layer prevents the penetration of steam into the insulation, the second provides the necessary strength of the base, and the third protects against moisture from the outside.
Each individual layer has the necessary perforation for good air exchange. The first layer removes excess moisture, allowing dried air to penetrate. The reinforcing layer retains warm air masses inside thanks to a special weaving of threads. The third layer provides a sufficient level of traction inside the structure.
Some types of membranes have an additional anti-condensation layer based on viscose or cellulose. She holds excess moisture, deposited on paper fibers. To naturally remove moisture from the membrane, a technological gap of 2.5 cm is provided between the vapor barrier and the finishing surfaces.
Features of vapor barrier installation
An important stage in protecting insulating materials is laying a reliable vapor barrier layer. All work is carried out during the repair or reconstruction of a finished building or during the construction of a new building. To correctly install a vapor barrier, you need to understand how to connect membrane sheets and which side to fix them to the insulating base.
Preparatory work
On at this stage work is carried out to select the appropriate type of vapor barrier, taking into account the features of the installation process, operational characteristics and material requirements.
Before laying a vapor barrier, careful surface preparation will be required. It is important to consider the type of material used in the construction of floors, walls, ceilings and roofing structures.
- During the construction of a log house, all structural elements are treated with protective antiseptics and fire retardants.
- When carrying out repair and reconstruction work, complete dismantling is carried out finishing, cleaning and preparation of surfaces:
Wooden elements are treated with compounds against aging, rotting and burning. Concrete, block and brick surfaces treated with deep penetration antiseptic compounds.
Proper preparation of surfaces will ensure a long service life of the insulating material and the entire structure.
Technology for laying vapor barrier on the ceiling
If the roof structure and interfloor ceiling are made of wood, then the installation of a membrane for waterproofing is carried out on a prepared base.
Roll or block insulation is installed in the space between the rafters and joists; the best option is mineral or basalt wool. Next, you can lay vapor barrier protection on the ceiling surface.
When the thickness of the insulation is equal to the height of the logs, an additional slatted counter-lattice is installed to maintain natural ventilation.
It is necessary to install a vapor barrier on the ceiling with a slight overlap on the walls around the perimeter, and special attention should be paid to the corners. It is better to place the joints on the joists and glue them on both sides with tape on a reinforced base.
Important! When installing a vapor barrier, sagging and deformation of the panels should be avoided.
For thermal insulation of flat roofs or concrete ceiling mounted from the inside waterproofing film on self-adhesive tape, then a lathing made of wood or metal is installed.
The height of the sheathing is determined based on the thickness of the thermal insulation material and the minimum technological gap for ventilation. The installation pitch is 3 cm narrower than the width of the heat insulator, which allows for high-quality styling insulator into the prepared sheathing cells.
Technology for laying vapor barrier on the floor
The installation scheme for vapor barrier protection on the floor is similar to how the material is laid on wall and ceiling surfaces.
The wooden floor is insulated using joists, on which a waterproofing layer is laid. Next, insulation is placed in the space between them - wool on a mineral or basalt basis. After this, vapor barrier material is laid.
The rolled material must be laid with an overlap of 12 cm, with the joints carefully sealed with metallized tape on both sides. A properly laid vapor barrier should completely cover the floor surface with an overlap of up to 10 cm on the walls.
To install a vapor barrier on a concrete base, you will need to install a sheathing, in the cells of which a waterproofing layer and a heat insulator will be laid.
Choosing a side for installing a vapor barrier
Once the material for the vapor barrier has been selected, you should consider important question– which side to attach the vapor barrier to the insulation. Such materials can be fixed as follows:
- Polyethylene films (reinforced and plain) are laid on any side, which does not worsen protective properties material.
- Foil films are installed with the reflective side facing the inside of the room to effectively reflect heat.
- Anti-condensation films are mounted with a fabric surface inside the room, treated - to a heat-insulating base.
- Membranes of any type are attached with a smooth surface to the heat insulator, and with a rough surface - inside the room.
- Foam-based insulators are laid similarly to membrane materials.
Important! Before laying the vapor barrier to the insulation, it is recommended to lay out the prepared material on a flat surface to correctly determine the inner and outer sides.
The face or the back of a vapor barrier?
If a breathable membrane is used to create a protective barrier, the main thing is to determine which side to lay the vapor barrier on - face or back.
The vapor barrier cake must be placed so that the protection is directed towards the heat insulator on both sides with the smooth back side, and with the rough front side facing the inside of the room.
The rough surface provides protection from moisture penetration into the insulation, and the smooth surface promotes maximum heat accumulation.
Determining the width of the overlap when installing the membrane
There are special markings along the edge of the insulating membrane to determine the width of the overlap of the sheets, which ranges from 8 to 20 cm.
The vapor barrier strips on the roof should be laid in a horizontal plane from bottom to top, overlapping each other with a width of 15 cm. At the ridge the overlap is 18 cm, at the valley - 25 cm.
On walls, ceilings and floors, the canvases are mounted with an overlap of 10-15 cm.
Is a layer required for ventilation?
At the bottom of the membrane vapor barrier there is a 5 cm ventilation gap, which helps prevent the formation of condensation on surfaces and heat insulation.
Diffusion membranes can be attached to insulation, plywood sheets or OSB. In a membrane with an anti-condensation layer, gaps up to 6 cm wide are located on both sides.
To create a gap for ventilation when insulating the roof structure, a counter-lattice is used. In the process of fastening a ventilated facade, a technological gap is created when installing racks located perpendicular to the vapor barrier.
Elements for fastening vapor barrier
To securely fasten membrane or film vapor barriers, wide-headed nails or metal construction staples are used. Most practical option fasteners - counter rails.
To increase the tightness of the structure, individual vapor barrier elements are additionally glued with double-sided adhesive tape or wide metallized tape.
To ensure long service life modern insulation materials, you will need high-quality vapor barrier protection. Otherwise, it will be difficult to obtain the optimal ratio of temperature and humidity indicators in the premises. The main thing in this matter is to choose the right material and know how and which side to lay to the heat insulator.
One of the main criteria comfortable life There is an optimal temperature level in the house, as well as a suitable humidity level. Provide good performance Properly installed layers of heat, moisture and vapor barrier will help. Moreover, correctly laid layers not only improve the microclimate in the house, but also protect the floors from the effects of various factors, including humidity. How to properly install a vapor barrier on the floor?
Floor vapor barrier
Hydro-vapor barrier film
How to properly install a vapor barrier on the floor
Why is vapor barrier needed?
Each house has its own specific microclimate inside. Here a person prepares food, takes a shower or bath, and does wet cleaning. Thanks to all these processes, a fairly large amount of steam is released into the air floating in the room, which tries to find a way out beyond the walls of the rooms. It has a fairly strong effect on all elements of the structure, and drops of moisture settle on the surface of the walls, ceiling, and inside the floor pie. The resulting condensate, willy-nilly, begins to penetrate into the structure of the materials used to build the house - it is absorbed into the wood, penetrates into the insulating layer, reducing performance characteristics materials, destroying them.
Floor insulation
In rooms located on the first floors directly above the ground or basement, the floors also experience increased exposure to humidity. Here, moisture also affects the materials from below. And the vapor barrier is installed precisely with the aim of reducing the level of impact on the floors, while this type of material does not interfere with air circulation at all - its flows can easily go outside, the rooms will “breathe”.
On a note! Vapor barrier is especially necessary when building houses made of wood. However, it will not be superfluous when constructing concrete structures, since it will reduce the level of humidity in the building.
Instructions for installing a vapor barrier
What is the difference between hydro- and vapor barrier
Vapor barrier is a thin film that is installed inside the floor pie. However, quite often it is confused with waterproofing, but these are completely different materials. So, the waterproofing layer is designed to prevent moisture from entering the room from outside. If water does reach the insulation, its characteristics will deteriorate significantly - it will no longer retain heat. This will be especially felt in winter, when the water inside the insulating layer turns into ice crystals. The floor will become colder, and in general it will no longer be so comfortable to be in the room. To prevent this from happening, it is necessary to lay a layer of waterproofing. In general, it does not allow precipitation to pass through it, groundwater and is laid outside the floor pie.
Waterproofing the floor on the ground
The vapor barrier is installed inside the floor pie. And it will protect the materials included in the structure of the base, no longer from moisture from the outside, but from condensation coming from inside the room, which is formed due to breathing, cooking and other processes accompanied by the release of steam and moisture.
Scheme of floor arrangement on beams
The main difference between these two types of materials is their structure. Waterproofing coatings They do not allow moisture to pass through, but are quite capable of allowing evaporation to pass through. But vapor barriers retain both moisture and steam, thereby protecting the insulation. Thus, the vapor barrier does not have a membrane structure as such.
Vapor barrier laid on the floor
On a note! Not all types of waterproofing materials are vapor permeable.
Types of vapor barrier materials
Several basic types of materials can be used to create a vapor barrier layer. This is a polyethylene or polypropylene film, the so-called diffuse membrane or liquid rubber. Previously, only roofing felt, roofing felt and other similar materials were used.
Polyethylene film
Polyethylene film is the cheapest and simplest material used to create a vapor barrier layer. It is quite thin, and therefore during installation it is important to be careful not to tear it. The film may or may not have fine perforations.
On a note! There is an opinion that film with perforation is used for waterproofing, and without it - for vapor barrier. This is due to the presence of small holes in the material.
Vapor barrier film "Yutafol N 110"
However, in any case, no matter what the film is, when using it you will have to create a ventilation gap. And since it will have to be done anyway, many do not think about the presence of perforation and simply buy the material that costs less.
Now there is another subtype of films made of polyethylene - it has a reflective layer coated with aluminum. This material has higher vapor barrier properties and is usually used in rooms where there are high levels of humidity and air temperature.
Vapor barrier film with foil coating
Polypropylene film is characterized by high quality and strength. It is easy to install and can last for many years. Polypropylene film is made not only from polypropylene - it also has an additional cellulose-viscose layer that can absorb quite a lot of moisture and retain it. At the same time, as the humidity level decreases, the layer dries out and is again ready to absorb it.
Polypropylene vapor barrier
When laying this type of film, it is worth remembering that the anti-condensation absorbent layer should be turned away from the insulation. And between the vapor barrier layer itself and the insulating material, a small gap is left for ventilation.
Diffuse membranes are perhaps the most expensive vapor barrier option. They are considered to be of the highest quality, are called “breathable” and are capable of not only protecting building materials from excess moisture, but also regulating the humidity level. Membranes are divided into single- and double-sided, and the materials are mounted in different ways - if when laying a one-sided version of the membrane it is important to observe which side it will be turned to the insulation, then the double-sided one can be laid as you like.
Such membranes are characterized by significant vapor permeability. They are made from a special non-woven artificial material and can have several layers. There is no need to leave a gap for ventilation during installation.
Diffuse membrane
On a note! Among the membranes there are those that are called “intelligent”. They combine several properties at once - they are able to work as a vapor barrier layer, provide waterproofing and are also a thermal insulation material. This type of membrane is able to regulate the level of steam depending on the levels of indicators such as temperature environment and indoor humidity.
When creating a wooden floor cake, liquid rubber is used extremely rarely for vapor barrier; it is more suitable for concrete bases. However, it is still a common enough option to talk about. This rubber is a polymer-bitumen composition prepared on the basis of water. It is applied very simply - sprayed on the base, and forms a seamless and durable coating - a kind of rubber carpet. When the polymerization process is completed, the material will not be able to pass through any substances.
Liquid rubber
Liquid rubber can be applied automatically and used to process spacious structures, or manually - this option is suitable for small rooms.
Brands of materials for creating vapor barriers
There is a wide variety of different brands of vapor barrier materials on the materials market. They have a lot of differences and may differ in price, quality and other factors.
Table. Brands of materials.
| Tyvek | Well protects against steam and moisture | Denmark | 5500 rub./50 sq. m. |
| Izospan | Protects from moisture, wind, steam | Russia | 13 rubles/sq.m. |
| Brane | Russia | 1100 rub./70 sq. m. | |
| Domizol | Excellent protection against steam, moisture, wind | Russia | 13 rubles/sq.m. |
| Polyethylene | It breaks, but protects well from steam | Russia | No more than 10 rubles/sq.m. |
"Izospan B"
Izospan is especially popular. There are several subtypes of it, and for floors it is recommended to purchase Izospan V. It is a two-layer version of the membrane. On one side it is smooth, and on the other it is slightly rough. The rough side holds capillary moisture well, absorbing it.
Installation features
The floor pie is made of several layers, including logs, a layer of waterproofing material, a subfloor, a layer of insulation, a vapor barrier layer, a layer soundproofing material and finishing coating. Before installing a vapor barrier, it is necessary to prepare the surface. If the structure is being built from scratch, then there will be no problems with installing this layer. The subfloor boards are simply treated with antiseptic preparations, leveled, and a vapor barrier material is laid on top of them. It is also recommended to cover protective compounds and lags.
Floor insulation with mineral wool
If the house has already been built and is undergoing a major renovation, then first it is important to remove the old flooring and other previously used materials. Next, it is important to check the strength of the logs and the rough foundation - if they sag or rot, they will have to be dismantled and replaced with new ones. All the trash in front further work removed, the smallest specks are removed using a vacuum cleaner.
The vapor barrier layer must be laid on a flat base without protruding nails. Otherwise it may be damaged. Immediately before installation, it is important to determine which side the vapor barrier material will be mounted. As for ordinary polyethylene film, there is no need to determine the side. If Izospan is used, then it is important to look at its color on both sides. It is laid with the light side facing the insulation. If the material has pile, then this side is mounted towards the room - the pile will absorb excess moisture.
Laying vapor barrier "Izospan"
On a note! To work with vapor barriers, a material such as tape is useful. It is used to connect the joints of individual coating strips. This is necessary to improve the tightness of the vapor barrier layer. In this case, individual strips of material are laid with an overlap of 15-20 cm on each other.
Installing a vapor barrier does not require special knowledge. The material is rolled out over the surface of the prepared floor and secured to it using small nails and a construction stapler. However, the easiest way is to use special adhesive tape.
Places that are difficult to reach or have an unusual shape are best treated with a bitumen-based coating agent. The reason for these actions is that in such places it will be quite problematic to lay and properly fasten vapor barrier material.
The process of laying "Izospan"
The insulation itself will be laid directly on top of the vapor barrier if the material is used to protect it from moisture not only from the inside, but also from the outside. Foam plastic, mineral wool or expanded polystyrene can be used as an insulating layer. It should fit very tightly wooden joists so that cold bridges do not form.
Another layer of vapor barrier is mounted on top of the insulation layer. It will no longer allow moisture coming from inside the room to reach the insulation and be absorbed into it.
On a note! Foil film perfectly reflects infrared radiation. Therefore, it is laid with the shiny side facing the room.
How to lay a vapor barrier
The vapor barrier must be installed in compliance with the technology, although in general this process is quite simple and understandable to everyone.
Step 1. Windproof material is spread over the subfloor.
Laying windproof material
Step 2. The film is laid so that its edges overlap the wooden logs.
The film is attached to the logs
Step 3. The material is fixed using a construction stapler along the joists.
A stapler is used for fixation
Step 4. After this, insulation boards are laid on the laid material. They must cover all the space between the joists.
Laying insulation
Step 5. Adhesive tape is glued along the perimeter of the wall in its lower part before installing the vapor barrier layer.
Adhesive tape is applied around the perimeter
Step 6. A vapor barrier layer is laid. Pieces of the required size are laid across the joists with a slight overlap on the walls. The film is laid so that it sags a little in the middle.
Laying vapor barrier
Step 7 The film is fixed using a construction stapler on the joists.
Fastening vapor barrier material with a stapler
Step 8 edge vapor barrier film, placed on the wall, is glued to it using the adhesive tape installed earlier.
Vapor barrier film placed on the wall is glued to adhesive tape
Step 9 The junction of the next layer of film is sealed using adhesive tape, which is glued along the edge of the previously laid layer.
The joints between the film pieces are sealed with adhesive tape.
Step 10 A new piece of material is laid so that there is an overlap at the location of the adhesive tape. The rest of it is again fixed to the joists using a construction stapler.
The second piece of vapor barrier film is laid
Step 11 The floor is being installed.
Floor installation
Video - Installing vapor barrier
Video - Vapor barrier films for floors “Ondutis”
Vapor barrier is a layer in the floor cake that should not be neglected, much less replace it with waterproofing material. It is thanks to vapor barrier that it will be possible to create a microclimate favorable for life in the house.
When renovating a house, it is important to follow the technologies for dismantling, processing and assembling all surfaces: walls, ceiling, floor, roof. Often, home-grown builders neglect such an important detail as vapor barrier material, out of ignorance or arguing that it is unnecessary. It often happens that those hired repair teams make unforgivable mistakes for which you still have to pay. In fact, a vapor barrier serves as a barrier to the penetration of moisture from outside into the floor “pie”, preventing the occurrence of condensation, fungus and rotting processes. Therefore, it is extremely important to know how to choose the right way to lay a vapor barrier on the floor and which side.
Variety of materials
To protect surfaces and insulation from moisture use:
- reinforced polyethylene film;
- aluminum coated film;
- film made of propylene fibers;
- membrane vapor barrier.
What where When?
The main role of a vapor barrier material is to protect wooden structures and insulating material from moisture, rotting and, as a result, premature destruction.
It is extremely important to use it on lower floors, above basements and basements, and especially above bathrooms and kitchens. It is also necessary to remember that the insulation protection must be double-sided, since wet mineral or glass wool almost completely loses its thermal insulation qualities. That is, the film is placed between the finished floor and the insulation material, as well as between the insulation and the subfloor. However, often the bottom layer is replaced with waterproofing.
Which side should I lay?
You need to know which side to lay the vapor barrier on the floor. Extremely important nuance, since incorrect installation technology for the material will negate all its properties.
A man lays vapor barrier material on the floor
Here are the instructions:
- The double-sided film is placed with the smooth side facing the insulation and the corrugated side facing up. The rough surface acts as a filter for steam and even the smallest drops of water.
- It is customary to lay polypropylene with the wicker side away from the insulation, and the smooth side inside.
- Installation of foil vapor barrier is carried out with the aluminum side facing the room, as it tends to reflect infrared radiation.
- Individual installation technology is possible for individual brands and types of vapor barrier materials.
- Before use, be sure to read which side to place the vapor barrier on the subfloor and insulation.
Laying algorithm
It's not complicated:
- First, the old flooring is dismantled down to the subfloor. Then the base is prepared: debris is removed, cleaned, leveled, treated with antiseptic and primer. Old floor beams or joists that have begun to collapse must be replaced with new ones.
- Hydro and vapor barrier of the subfloor is carried out, preventing moisture from entering the insulation from the ground or lower rooms. Film strips are laid right side(see above) overlap by 15-20 cm. The edges must be glued with reinforced or double-sided tape. Also, the vapor barrier should extend 10-15 cm onto the walls and joists. It can be attached to beams and joists with metal brackets.
- A layer of insulation is laid on top of the film with the seams staggered and a thickness of at least 20-30 cm.
- A second layer of vapor barrier is laid on top of the insulation, also with an overlap and gluing the joints. If installation is carried out on wooden floor joists, it is necessary to lay the film so that it sag slightly: this way a ventilation gap is created between it and the finished floor. However, it is also recommended to put counter-battens on the logs on top of the vapor barrier, which will prevent the film from coming into contact with the finished floor.
- The finished floor is filled and then finished with the finishing floor covering.
Now you know how to install a vapor barrier on the floor and will not make the mistake of doing your own repairs.
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In winter, when it’s frosty outside but the inside of the house is cozy and warm, unnoticeable steam forms in the rooms. And this steam must leave the room freely. To accomplish this task, a vapor barrier is installed. You need to know which side to lay the vapor barrier on the floor, walls or ceiling.
Why do you need a vapor barrier?
Vapor barrier material is used for normal moisture circulation indoors. If you ignore the vapor barrier, then moisture in the air can enter the insulation and gradually destroy the material.
If the construction of buildings is carried out from a material that is already insulated, then the vapor barrier will serve as protection against the entry of harmful substances into the premises.
Insulation is a heat-insulating material. Depending on the origin of the feedstock, it is divided into:
What kind of vapor barrier is needed?
- organic thermal insulation - the basis is wood, plants, peat, animal hair;
- inorganic thermal insulation - mineral wool, fiberglass, concrete.
The installation of a vapor barrier layer is carried out to maintain a comfortable temperature inside the house, preventing air from penetrating through the cracks of the building.
When using insulation that absorbs moisture well, you cannot do without a vapor barrier. In its absence, moisture is absorbed into the structure of the insulation and there it turns into water. With time thermal insulation characteristics insulation material will decrease. After a certain period, it will be possible to observe the appearance of fungus and mold. The use of a vapor barrier creates a kind of shield between the insulation and the internal air of the apartment.
Correct installation of the vapor barrier will allow the insulation to last a long time and effectively.
Types of vapor barriers
In modern construction, vapor barrier is successfully used to protect organic and inorganic thermal insulation materials. It comes in the following types:
- Film.
- Diffusion membrane.
- Energy saving membrane.
- Roll vapor barrier.
Film– a blind vapor barrier material that retains moisture and does not allow moisture to pass through. Due to its low cost and excellent waterproof characteristics, the film is used not only in the construction industry, but also for domestic needs. Films vary in thickness, number of layers, and surface quality. It can be smooth on the outside and rough on the inside. Water always remains on the surface of the film.
Summary table of vapor barrier film properties
Diffusion membrane. This type of vapor barrier material consists of a polymer film and polypropylene and has limited vapor permeability. Water vapor contained in the insulation immediately evaporates.
Energy saving membrane resistant to elevated ambient temperatures due to its metallized outer layer. Vapor barrier should be installed in rooms with high humidity and temperature. The material is capable of reflecting infrared radiation.
Roll vapor barrier allows moisture to pass in two directions. Convenient to use when insulating large surface areas.
The thermal insulation and vapor barrier characteristics of a structure depend on the choice of material. A careful approach to the selection of the necessary products will ensure the comfort and coziness of the premises and will help extend the service life of the entire structure.
Principles of installing vapor barriers to different surfaces
Manufacturers of vapor barrier films, focusing on consumer desires, produce their products in different directions:
Vapor barrier installation options
- for work on and under the roof;
- on vertical wall surfaces;
- on the floor.
Vapor barriers can be installed on any surface. When using vapor barrier material on wooden structures use a film with a membrane. Polymer or bitumen mastic can be used for any type of surface. On concrete walls It is recommended to install a vapor barrier with a metal outer layer.
Its use will be much more effective if the working side is prepared in advance. Preliminary work depends on the characteristics of the material with which the building is built.
Breathable membranes
When building a wooden house, first they impregnate everything wooden surfaces special means against insects and harmful bacteria. Only after completing a set of preparatory work are they started to install the vapor barrier layer.
Most quality material for insulation of wooden floors - breathable membranes. The body of the membrane consists of a layer of anti-condensation fibers that absorb and accumulate moisture. There are single-sided and double-sided membranes. In the latter option, moisture is absorbed from both sides at once, so the double-sided breathable membrane can be laid with either side to the floor.
When carrying out a major overhaul, all outdated insulating coatings are dismantled. Surfaces are thoroughly cleaned and impregnated with special disinfectants. Then you can lay the vapor barrier. Concrete surfaces do not require special treatment with special means; they just need to be cleaned.
Features of installation on various surfaces
Installation of a vapor barrier layer is not particularly difficult; it must be done carefully preparatory work and know the main stages of installation.
Laying on the floor
Film – best option insulating the floor from moisture. On the ground floor, the insulation layer below is protected by a waterproofing device, and closer to the premises - by a roll of insulating film, which is laid overlapping. The joints are taped with metallized tape or tape.
If it is interfloor or attic floor, then the film is unfolded with the smooth side down to protect against water vapor coming from the slab or floor logs.
Laying vapor barrier on the floor
Ceiling insulation
Used in rooms with high moisture content in the air. These can be bathrooms, showers, baths, saunas. The vapor barrier is securely overlapped and the joints are sealed. The reflective side of the material is directed indoors. Special attention given to the corners of the room, the insulation should overlap slightly on the walls around the entire perimeter of the room.
Ceiling insulation with vapor barrier
Vertical surfaces
For such surfaces, diffusion membranes are used, which allow air to pass through rather than moisture. The walls must “breathe”, so impermeable film is not used. In case of external work, the product is laid with the smooth side facing the insulation. When installing, the film is slightly stretched.
Wall insulation
Roof mounting
The purpose of the vapor barrier is to protect the rafters from mold and prevent the formation of condensation in the insulating layer. Installation is carried out with an overlap and sealing of the seams. The main condition is to ensure the tightness of the roof in combination with vertical elements building.
Roof vapor barrier - device
Basements, balconies and underground structures
Balconies, basements and underground rooms are in contact with cold outside air. For balconies, dense foamed polyethylene is used, the reflective side of which is directed indoors. For other structures, membrane film is used.
Insulation of underground structures
How to distinguish the vapor barrier side
When working with vapor barrier materials, it is necessary to find out which side the product should be laid in relation to the insulation. The location of the vapor barrier will determine the degree of moisture absorption by the insulation and its service life. The instructions for the product indicate how to install it correctly. But what if there are no instructions? In this case, the installation method is determined independently, taking into account the following points:
- if there are sides of different colors on the vapor barrier material, the lighter one is placed next to the insulation;
- the outer side of the product has a rough surface;
- If in doubt, take a glass of hot water and place it on the vapor barrier area. Condensation forms on the waterproof side.
The polyethylene film is laid with either side facing the insulation, while the diffusion film has one smooth surface, which should lie towards the insulation. By preventing the insulating layer from getting wet, it allows moisture to pass through the smooth side without hindrance.
Installation of vapor barrier
- By placing the barrier with its smooth side facing the thermal insulation, the influx of steam and the formation of rotting processes in wooden structures are eliminated;
- when installing a thermal insulation layer outside the building, the insulating layer is placed outside the room;
- the film should fit tightly to the insulating layer;
- When sealing joints, wide adhesive tapes and tapes are used;
- when working with window and door openings, it is necessary to leave a small supply of vapor barrier film;
- The film should be protected from direct sunlight;
- Before starting work, the most critical places are determined - areas of interaction between warm and cold air.
When performing work on installing a vapor barrier film, it is important that the product is attached correctly. Otherwise, the error will lead to ineffective thermal insulation.
When building and renovating a home, you have to deal with many unfamiliar concepts. One of these is vapor barrier. From the name it seems clear that this material should cut off steam, but why and where. After all, there was no vapor barrier before? Did not have. But the toilet and bathtub were on the street, they didn’t do laundry at home, and they used glassine and roofing felt. These are also vapor barrier materials. Well, then let’s figure out how vapor barrier differs from waterproofing and what types it comes in. You will also need to find out which side to lay the vapor barrier on, how to install it and what to fasten it with.
As you know, water molecules are larger than steam molecules, so not every material that does not allow water to pass through does not allow steam to pass through. That is, not every waterproofing material retains water vapor, so waterproofing materials divided into two groups:
- Vapor permeable waterproofing. This is precisely waterproofing, which retains only water without interfering with the passage of steam.
- Vapor barrier or vapor barrier. Water does not pass through these materials in any form.
Once again: vapor-permeable waterproofing conducts steam, but does not conduct water. The vapor barrier/vapor barrier does not conduct either steam or water. As you can see, they work differently, so they have different areas of application.
An example of the use of vapor barrier and waterproofing in a floor structure along joists
Let's give an example. Vapor-permeable waterproofing is used in floor construction along joists with mineral wool insulation. It is hemmed from the bottom and prevents water from penetrating into the thermal insulation, but does not prevent steam from escaping from the mineral wool. This allows you to maintain the insulation in normal condition.
In the same case, the vapor barrier is placed on top of the insulation - on the room side. IN in this case it protects the insulation from both steam and water penetration. How does the whole structure work? The vapor barrier does not allow water to pass through, which can be spilled on the floor in the room, and it does not allow steam to pass from the room into the insulation. But, all the same, some part of the steam gets inside the insulation through imperfect joints and other defects. Due to the fact that the bottom of the insulation is lined with vapor-permeable material, it can evaporate.
The simplest pie of a wooden floor using joists with insulation If such a floor is made above the underground, the moisture that penetrates into the underground from the soil through the vapor-permeable film enters the insulation. This is not very good, but a vapor barrier placed on top prevents moisture from entering the house. And wet insulation dries out if there is ventilation in the underground. So, in order for the floor to be dry and warm, it is necessary that there are properly arranged vents in the base.
Is it possible to replace waterproofing with vapor barrier in this cake or vice versa? No. If you lay a vapor barrier underneath, the water will be trapped in the insulation. There it will accumulate and either break through the film somewhere and spill out, or it will simply lead to the insulation turning into dust.
Vapor barrier in a concrete floor pie
In the insulated floor pie concrete base everything is exactly the opposite. Let’s say right away that a vapor barrier layer is not always needed. This layer is needed if:
- concrete is poured on the ground;
- unheated room below;
- below is a room with high humidity (bathroom, kitchen, swimming pool, laundry room, etc.).
If concrete floor above a heated room, neither waterproofing nor vapor barrier is required. You can pack them just in case, but you can also save money.
As you can see, a vapor barrier is laid below, and a vapor-permeable moisture barrier is installed on top. Why? Because the situation is the opposite. Concrete will not be harmed by high humidity, it will only become stronger, so it is very logical to lock moisture in concrete and this can be done with the help of a vapor barrier. It will cut off both capillary suction and prevent the vapor form from leaking into the insulation.
Using a vapor barrier for a wooden floor over a concrete slab It is better to lay vapor-permeable waterproofing on top of the thermal insulation. It will prevent water from getting inside, but will help maintain the normal humidity of the thermal insulation, as it will not prevent evaporation. Is it possible to replace steam and waterproofing here? Again, no. Otherwise, everything will not work correctly.
What type of vapor barrier is there?
As you already understood, if insulation is installed in the floor structure, which absorbs water and changes its properties when wet (mineral wool in any form, for example), it is necessary to take measures to ensure that moisture in no form penetrates into the insulation. This is why vapor barrier materials are used.
A vapor barrier is a material that does not conduct water vapor. There are two types:
- with one-way conductivity;
- vapor-tight.
With one-way conductivity - these are membranes. They are more like non-woven fabric. In any case, on one side they have non-woven fabric. They do not allow steam to pass in one direction, but they do so in the other. This type of material appeared not so long ago, and if it “works” as it should, it’s a very good thing. But while there is little experience in using it, they are trying to avoid it.
Materials that do not conduct steam at all, in any direction, are made on the basis of film. Most often this polyvinyl chloride film(PVC), but other polymers can also be used. The most durable polystyrene, but it is also the most expensive. Vapor-proof films can be reinforced - three-layer or without reinforcement.
There are also vapor barrier materials with a heat-reflecting effect. They can be distinguished by a shiny surface on one side (there are materials on both sides that reflect heat). A shiny surface can be:
- thin foil glued to the surface;
- metallized lavsan;
- metallized polypropylene.
What is metallized film used for? It reflects thermal radiation into the room. This way you can save on heating costs. Here's just one thing: reflection works when there is an air gap. That is, in a floor pie it makes sense to use such a film in floors along joists. It can be used to cover mineral wool, spreading a reflective shiny layer into the room.
How to check if the vapor barrier is working
There is a very simple way to check the effectiveness of a vapor barrier. You need a small piece of material and two glasses of the same diameter. Pour boiling water into one glass, cover it with a piece of the material being tested, and place the second glass upside down on top. If the material works as it should, the second glass remains dry.
If drops form on the walls, “fog” appears, the material conducts steam. Perhaps you have a vapor barrier with one-way conductivity, then you need to turn it over and repeat the tests. The situation has not changed? This is a vapor-permeable material with two-way vapor conductivity.
Checking the operation of the vapor barrier
Which side to lay the vapor barrier on?
As a rule, membranes have one side rougher and the other smooth. The rough side is often positioned as anti-condensation - drops of condensation do not form on it. In practice, no difference was found between membranes with and without an anti-condensation surface. The thermal insulation underneath is in the same condition.
Which side should vapor barrier membranes be laid on? Depends on where you are using them. But the general rule is the smooth side towards the insulation, the rough side towards the room (outside). In general, serious manufacturers provide each roll with instructions that spell out the installation rules. Read it before you start. It specifies exactly which side to install the vapor barrier from that particular manufacturer. If you buy material by the meter and not by the roll, either ask for instructions or take a photo of it.
When using film, it does not matter which side the vapor barrier is placed on. She doesn't pass steam in both directions There are a couple of tips that will help you decide which side to lay the vapor barrier without instructions:
- The material is placed so that the roll rolls out to the right.
- Logo facing up.
- If the film has a metallized layer, the shiny side should face you.
If there are no markings on the film, and it really is a film and not a membrane (with or without reinforcement, it doesn’t matter), it doesn’t matter which side to lay the vapor barrier on. Films have the same characteristics in both directions, so the side does not matter here.
If roofing felt is used as a hydro-vapor barrier, it also does not matter how it is laid. It is important to make sealed seams and follow other installation rules.
How to lay a vapor barrier correctly
The importance of vapor barrier, we hope, is clear and how a vapor barrier differs from waterproofing too. We also seem to have figured out which side to put the vapor barrier on. All that remains is to find out how to install it correctly. There are only a few rules, but they are all subordinated to one goal - to make the coating truly airtight and vapor-tight. Therefore, if the manufacturer recommends certain types of joint tapes, it is better to use them. You can, of course, buy the most ordinary tape, but the savings will not be that big, but the damage from a poorly taped joint can be significant. It can even negate the whole idea of a vapor barrier. So, here are the rules by which you need to lay a vapor barrier:
When installing a floating floor on the ground, a vapor barrier film is spread on concrete preparation or on a concrete floor. When laying the material, in places where it bends on the walls, make small folds - 3-4 cm each. If this is not done, the film or membrane is stretched and voids form in the corners. Technologically, this is not fatal, there will be no great harm, but the vapor barrier stretched in the corners easily breaks, and a torn vapor barrier will not hold anything in place. Now you know not only which side to put the vapor barrier on, but also how to lay it correctly. That is, you can do everything right.
How and with what to fasten
If a vapor barrier is used in a floor pie along joists, there are options for its installation.
To be absolutely sure that no steam will pass through the holes near the brackets, foamed polyethylene or polypropylene can be laid between the film and the fixing bar. These materials are often used as a backing for laminate flooring. The material also does not allow steam to pass through, and due to its “foaming” it has considerable elasticity. It will definitely block the steam access.
How and with what to attach vapor barrier to walls? Any more or less serious manufacturer of vapor barrier films has specialized connecting tapes. They are available for different wall materials, so choosing is easy. These tapes themselves have double-sided adhesive. The gluing procedure is as follows:
It's that simple. Once glued, the excess can be cut off. And finally, you know not only which side to lay the vapor barrier on, how to lay it correctly, but also how and with what to fasten it.
When insulating a house, it is important to lay the vapor barrier facing the insulation correctly. After all, if the norms are violated, cold will enter the house, and the heat inside will not be retained. In our article we will take a closer look at all the nuances of installing a vapor barrier.
Which side should the vapor barrier be laid against the insulation?
Before determining which side to install the vapor barrier, you should consider the installation locations vapor barrier membrane:
- If your insulation will be installed from the facade, then the vapor barrier should be fixed from the outside. This way you will make waterproofing;
- The space under the attic, for example, the ceiling or ceiling, requires laying a vapor barrier membrane underneath the insulation;
- When treating the roof and ceiling, it is necessary to use an antioxidant vapor barrier. Diffusion and volumetric coatings are in demand. They should be laid on top of mineral wool;
- If your roof and ceiling do not have additional insulation, then in this case the vapor barrier is attached to the rafters from the bottom side;
- When thermally insulating the floor and walls from the inside, it is necessary to additionally lay a vapor barrier film on the outside of the mineral wool.
Many builders, even those with extensive experience, do not pay attention to which side to attach the vapor barrier film to the insulation. When choosing a vapor barrier film, it is better to give preference to a material whose front and back sides are the same.
But many people choose options with different sides, and often with an antioxidant insulator. In this case, you need to know that the fabric surface is the wrong side. It is located in inner part rooms. The metal plane of the foil membrane should also be positioned. That is, the shiny side faces the interior of the room.
Regardless of the vapor barrier material, it is laid with the rough side facing the room and the smooth side facing the insulation.
When purchasing diffusion components, you should carefully study the instructions for use. Various manufacturing companies produce double-sided and single-sided vapor barrier films.
In most cases, the dark side of the film is the outer side.
What types of vapor barrier membranes are there?
Membranes used in construction are:
- Vapor permeable.
- With vapor barrier properties.
When using mineral wool as insulation, to protect it from moisture with inside arrange an additional layer of vapor barrier. If the walls are protected from the outside, there should be no pores or perforations in the components.
When choosing, you need to pay attention to the vapor permeability coefficient. It should be as small as possible. A good option There will be a purchase of ordinary plastic film. The material that is additionally reinforced will be of higher quality. And if the vapor barrier has an aluminum foil coating, then such a film will be of high quality and durable. Using a vapor barrier indoors increases humidity. Therefore, do not forget about installing a high-quality ventilation system.
Special vapor barrier films contain an antioxidant coating. With its help, moisture does not accumulate on the insulation. They are often used in areas that are susceptible to corrosion. For example, in materials such as corrugated sheets, metal tiles and others. The rough back surface helps remove moisture. The fabric side should face outward, so that a distance of 2 to 6 cm is maintained from the insulation.
The building membrane is used to insulate the outside of the house. It is able to protect the material from bad weather conditions and carries out evaporation. Usually the vapor barrier has small pores and therefore water is removed from the insulation into the ventilation ducts. Thanks to this, the insulation dries quickly.
There are several types of vapor-permeable films:
- Diffusion membranes. The vapor permeability coefficient can be from 300 to 1000 g/m2.
- Pseudo-diffusion. They allow no more than 300 g/m2 of vapor to pass through during the day.
- Superdiffusion membranes. The evaporation coefficient is more than 1000g/m2.
The pseudo-diffusion type of vapor barrier is a high-quality protection against moisture, so it is often laid under the roof as an outer layer. Do not forget about the arrangement of the air gap. The disadvantage of this type is poor vapor conductivity, so this film is not used for facade treatment. Condensation will begin to accumulate on the surface of the insulation, as dust and various debris will clog into the pores of the membrane.
In the other two types, clogging of pores is eliminated. Therefore, you can not leave an air gap and additionally install lathing or counter-battens.
In membranes of diffusion films of volumetric design, a ventilation layer is pre-provided. The structure of such a film is very similar to the antioxidant type. The only difference is the release of moisture from the insulation. If the roof slopes slightly, condensation will not drain through the bottom.
The need for an air gap at the membrane
It is always necessary to leave an air gap. A gap of 5 cm is placed on the underside of the film. This way you can avoid condensation on the floor, walls or insulation. When using diffusion film, it can be attached to moisture-resistant plywood, plinth or thermal insulation. A layer for ventilation is installed on the outside. When using an antioxidant component, an air gap of 4-6 cm should be made on both sides.
When installing a vapor barrier on the roof and ceiling, to create a ventilation gap, you need to install an additional counter-latten made of wooden blocks. When installing horizontal posts and profiles that are positioned perpendicular to the wall and film, a gap should be left for the ventilated façade.
Rules for attaching vapor barriers
You can attach the film to the walls, ceiling or floor using a stapler or wide-headed nails. But the best quality option would be to use counter rails.
The vapor barrier film should be laid with an overlap of at least 10 cm. After attaching the vapor barrier, the joints must be glued special tape or tape.
For a qualitative relationship between moisture and temperature building structure, and membranes will also help for a long service life. Without their participation, it is impossible to achieve such qualities. When installing a vapor barrier, all rules must be followed. Many manufacturers indicate on the packaging recommendations for installing vapor barriers.
It’s a pity, but any good thing, any excellent material can be ruined. The worst thing is when it happens out of ignorance. This fully applies to the insulation and protection of the thermal insulator. Failure to comply with technology leads to disastrous consequences. The house is cold, energy consumption has not decreased, and there is leaking from the ceiling. When opened, it turns out that the insulation is damp, the rafters have begun to rot. At this moment we begin to remember: “so that this doesn’t happen?”
The following types of insulation are produced and widely used:
- polyurethane foam;
- expanded polystyrene (extruded and foamed);
- organic (natural);
- mineral (basalt).
Due to its high hygroscopicity, the latter type of insulation requires the mandatory installation of a vapor barrier.
There are several types of vapor barrier:
- roll with impregnation;
- liquid (coating);
- adhesive (sheet and roll);
- polyethylene (films);
- reflective (with aluminum coating);
- “breathable” (membranes).
For most materials used for vapor barriers, it does not matter which side they face in one direction or another. This is possible due to the uniformity of the components used, the solidity of the structure, and the simplicity of the design. When laying the last two types, it is necessary to understand which side to attach the vapor barrier to.
Choosing vapor insulation
Before choosing and purchasing a vapor barrier material, you need to figure out which one will provide reliable protection for the insulation in specific conditions.
Use roll materials with impregnations of bitumen or coal tar are recommended for temporary insulation of structures during construction. They are not convenient and difficult to install. Sealing of joints is ensured by gas burners, which is not very convenient and safe indoors.
It is not entirely rational to insulate the ceiling and walls with coating compounds due to the fairly high cost of the material and increased labor intensity. This method is more suitable for insulating concrete floors in rooms with high humidity (washing rooms, steam rooms). When applied in two layers, they provide complete waterproofing of enclosing structures.
Protecting installed insulation from steam using adhesive materials is not justified due to high labor costs. Such insulators are successfully used to insulate joints of various building materials and communication passages.
When installing polyethylene film as a vapor barrier, the question of which side to lay correctly does not arise.
It has identical opposite surfaces. Some experts recommend using it only for wind protection, temporary protection of insulation from atmospheric precipitation, insulation of concrete floors. It should be remembered that polyethylene used in this capacity ensures complete insulation of the enclosed space with tight joints. When there are temperature changes or differences between the internal and external environments, water condensation forms on its surface, which will ultimately end up in the insulation. To prevent this process, good ventilation of the protected volume must be ensured.
- short service life;
- low strength under mechanical stress;
- high degree of deformation at high and low temperatures.
What bad steam has in store for us?
During human activity, air saturated with water in varying concentrations is released into the surrounding atmosphere. Cooking, washing, watering indoor plants, cleaning increases the concentration of steam. He climbs up and tries to leave the room with high temperature outside, where the temperature is lower. Due to temperature changes, it condenses and settles on the objects surrounding it: joists, rafters, insulation.
Even wood treated with protective antiseptics and painted iron are rented out With I, and begin to rot and rust. Mineral heat insulator, when moistened by 5%, retains heat 2 times less.
The main reason for what is happening: either a completely missing vapor barrier, or ignorance of which side to lay the vapor barrier against the insulation.
What does the membrane consist of and how does it work?
“Breathing” membranes are a complex set of materials that perform different functions. One cuts off steam, the second is a power base, the third prevents moisture from entering from the outside. Some films have only two layers (there is no reinforcing layer). Understanding the functioning of the material leads to an understanding of how to properly install a vapor barrier.
Each layer has holes for air passage. The small diameter of the first level cuts off moisture, allowing the dried flow to pass further. The reinforcing layer does not interfere with its passage, due to the rather rare arrangement of the power threads. The larger diameter of the holes in the third layer creates the necessary draft to prevent air stagnation in the membrane.
Some vapor barrier products have a special anti-condensation layer made of viscose and cellulose. It is rough to the touch. It is in it that moisture is retained, settling on thin fibers. Accumulated moisture is removed naturally. To ensure evaporation, a ventilation gap is arranged between the material and finishing room at least 25 mm.
Let's look at how to attach a vapor barrier and how to lay it, using the Nanoizol membrane as an example.
We insulate roofs and walls with external insulation
Installation of vapor barrier on the roof and wall begins before laying the insulation. If you install the vapor insulation incorrectly, you will have to disassemble the entire “pie”.
After treating the frame with an antiseptic, a vapor barrier film is installed on the roof or wall.
It is installed from the inside close to the joists (rafters) or rough sheathing. Fixed with staples or galvanized nails on a wooden base.
A vapor barrier is installed on concrete, block and brick surfaces using connecting tape.
On the walls and inclined surfaces The vapor barrier film must be laid from bottom to top in horizontal stripes. At the same time, overlap the lower panel with the upper panel by 10 cm. At the same time, the vapor barrier provides wind protection for the insulation.
Correctly lay the vapor barrier, with the smooth side close to the insulation, the rough side inside the room (against the wall). The tightness of the connection to the enclosing structures, pipelines, and ventilation must be ensured with connecting tape.
After correct installation vapor barrier on the ceiling, a lath of 3x5 cm is installed for installation of the finishing, insulation is laid on the wall. Protect the wall insulation from external influences using windproof film and finishing.
Insulation of interior partitions
During reconstruction or major renovation In a private house, you have to isolate heated rooms from unheated ones. For example, a cold corridor (entry) from living rooms. In this case, which side should the vapor barrier be laid on?
All wooden materials frames are treated with septic tanks to protect against insects and rot.
Installation procedure:
- a counter-rail is placed on the enclosing structure, providing a ventilation gap;
- it is necessary to attach a vapor barrier to the laid slatted frame with the smooth side facing the inside of the room;
- frame racks are installed on top of it;
- insulation is laid between the racks;
- a vapor barrier film is installed on the installed racks, with the rough surface facing the room;
- Nanoizol is secured to the frame using staples or nails with a wide head, then counter-battens, followed by installation of front panels or trim.
We protect interfloor ceilings
Correct installation of vapor barrier frame floor is done as follows:
- depending on the material used, the supporting structures are treated with compounds that provide long-term protection during operation;
- on the underside of the ceiling, Nanoizol is secured with staples or tape, with the rough side facing the inside of the room and secured with longitudinal counter-battens;
- Thermal insulation is placed on top of the frame close to the insulator (the height of the racks should be equal to the thickness of the insulation);
- a vapor barrier is laid out on top of it with its smooth side close to the insulation and fastened with longitudinal counter-battens (the overlap of adjacent panels should be at least 20 cm, the panels are connected to each other with connecting tape);
- The floor of the upper floor and the ceiling of the lower floor are installed across the counter slats.
Cutting off the attic and basement
How to make a vapor barrier for an unheated basement and attic?
Correctly installing the vapor barrier of the base is somewhat more difficult than in other cases.
It must be assumed that it is best to carry out work in the following sequence:
- we provide a ventilation gap of at least 5 cm between the ground level and the expected floor level;
- we lay pre-treated logs at a distance equal to the width of the insulation;
- We fix the subfloor from a board (you can use an unedged one) or slats onto the floor joists;
- Nanoizol must be laid with the rough surface down, going around the logs;
- we lay the heat insulation (the insulation should be placed with slight compression to prevent slipping during operation);
- after laying the thermal insulator, we install the vapor barrier with the rough side up;
- we secure the insulation material with a counter batten with a height of at least 25 mm;
- We install the finishing floor.
Vapor barrier and installation of attic insulation is carried out in the same manner as for interfloor slabs. It is necessary to lay the Nanoizol vapor barrier with a rough surface towards the inside of the room, and a smooth surface towards the insulation. If the attic is not heated, we install waterproofing under the roofing material, protecting the upper part of the insulation with the subfloor of the attic.
Protection from water and steam in baths and saunas
The material coated with thin aluminum foil works well to provide reliable water vapor barrier in damp rooms with elevated temperatures. An example of such insulation is Izobond FS premium class. Aluminum foil ensures that up to 90% of the released energy is returned to the room. This allows you to quickly raise the temperature in steam rooms and maintain it at high level without additional energy consumption.
Proper vapor barrier involves treating the frame with septic tanks to protect it from insects and rot. After installing the external insulation, the membrane is laid on the insulated ceiling and walls with the foil side facing the inside of the room. It is easier to lay a vapor barrier on the ceiling by first cutting the rolled sheet into pieces of the required length, taking into account the required penetration vertical surfaces not less than 10 cm.
The installation instructions do not provide for overlap of aluminum vapor barrier. Ensuring tightness is done with aluminum self-adhesive tape. When using reinforced double-sided construction tape, at least 10 cm of insulation layers are applied. This ensures that the properties of the tape, which is not intended for use in high temperatures, are preserved.
The acquired knowledge of which side to lay the vapor insulation against the insulation, the correct fastening of the vapor barrier, will ensure the preservation of heat in the house and comfortable conditions functioning of the insulation for a long time.
