Foil vapor barrier: types and applications

Materials used in the construction of roofs and arrangement of premises with non-standard temperature and humidity operating conditions are endowed by manufacturers with special properties. They not only easily resist the attacks of steam-saturated hot air, but also create a “thermos” effect, due to which energy consumption for heating is greatly reduced.

These specific products include foil vapor barrier, the installation of which allows you to solve a lot of important problems in the construction of building structures.

Application area

The described materials are used as a vapor barrier in rooms with high humidity, such as baths and saunas. The film does not melt, does not release substances hazardous to human health into the air, and can be used at temperatures up to +120 °C.

When installing modern steam rooms, the reflective properties of foil vapor barrier are very important, because the sauna should warm up in a short time after heating the stove, and energy costs should be reduced. However, foil vapor barrier is used today not only in the bathhouse.

When building a frame house, conventional vapor barriers are increasingly being replaced with foil ones. With the same heating power, using this approach it is possible to increase the room temperature by 2 °C. However, such material must be used wisely, because it should not be used for internal thermal insulation of buildings made of concrete and brick, as well as other heat-intensive materials.

What kind of material is this?

Foil insulation is a roll of insulation consisting of 2-3 layers . The first layer is the base, the main material that performs a thermal insulation function. The second layer is foil glued to the base, reflecting heat into the room and protecting the base layer from external influences.

The third layer is a self-adhesive base covered with a protective film. This layer is not always present in insulation materials; if it is not present, then additional special glue is purchased for installation.

How does it work?

Due to the reflective effect, the foil returns the heat generated from any source .
In other words, foil insulation only works if there is an open source of heat in the house. This could be a UV heater, stove heating, or fireplace. The heated air will not escape into the walls, floor and roof to the street; the foil retains the heat indoors.

It also has waterproofing properties. If you lay a layer of foil insulation under the floor with the foil facing the wood, the wood will stop accumulating moisture from the ground. This way, floor joists and boards will not rot for many years to come.

Recommendations for use

If the walls are frozen, this will worsen the microclimate. As for a wooden house made of timber or logs, foil vapor barrier is ideal for internal insulation. It can also be used for unheated loggias, laying it under the finishing floor covering to make it warmer. When glazing open balconies, when the perimeter is supposed to be finished with sandwich panels that do not emit heat, foil vapor barrier allows you to reduce heating costs.

Rules for laying foil insulation

The foil side of the insulation should be directed inside the room.
There are rules for laying thermal insulation with foil.

• The parameters of foamed polyethylene allow the amount of living space to remain unchanged. You can lay the material using a simple construction stapler.
• You need to lay foil insulation on the floor so that the aluminum side of the material is located towards the inside of the room.
• Basalt wool is placed with the foil layer facing up. You need to work with this material in special protective clothing and a respirator, as it releases substances harmful to humans. For convenience, basalt is sawed into lamellas (strips) of the required width.
• It is important to attach polystyrene foam boards to the floor in the right direction. They are laid under linoleum close to each other. The foil ensures the tightness of the connection.

Each type of material is attached with the side with foil inside the room. If you lay the insulation incorrectly, most of its characteristics will become useless.

Types of foil vapor barrier

Foil vapor barrier is offered for sale today in a wide range. In order for the material to perform its functions, it is important to make the right choice. It is necessary to pay attention to the fact that the polymers included in the substrate may have different structures. They consist of polypropylene foam and polyethylene foam. For more impressive temperatures, the first option should be used, while the second is relevant for a less aggressive environment.

Foil vapor barrier for baths is presented in the “Penotherm” variety. In this case we are talking about a material that includes foamed propylene foam. The material can be used at temperatures ranging from -40 to +150 °C. Vapor barrier is characterized by a low-hazard toxicity class and moderate flammability. There is almost no thermal shrinkage during use.

If you want to install a heated floor system, you should prefer NPPLE. This variety can also be used for a steam room. Foil vapor barrier "Izospan FB" is designed to form a vapor barrier in saunas and baths. The material can be used at fairly high temperatures. That is why the Izospan vapor barrier plus foil insulation is excellent for particularly difficult conditions.

How to attach a vapor barrier

The choice of fastening method depends on the type of vapor barrier material used. Polyethylene and polypropylene films are secured with small nails or with staples and a construction stapler.

Construction stapler (mechanical)

In order to minimize damage, it is advisable to use wooden planks that press the film against the guides, and drive staples/nails into the plank. Membranes can be attached in the same way. They are not as torn as films made of polyethylene or polypropylene, and they are easier to work with.

Attaching the vapor barrier

The sheets of rolled materials are laid one on top of the other with an overlap of at least 10-15 cm, gluing the joints with adhesive tape. You can use specialized, foil or regular adhesive tape.

Double-sided adhesive tape UNIBOB based on cotton fabric. An adhesive layer based on synthetic rubber, which ensures high quality gluing of vapor-waterproofing sheets

Foil tape must be used at the joints of foil materials, otherwise most of their effectiveness is lost. When gluing joints of other materials, manufacturers recommend using their own adhesive tape, but they do not explain their differences and advantages.

Please note that during installation the vapor barrier sheets should not be stretched: they tend to stretch/shrink when temperatures change. To avoid ruptures during tension, you need to leave a small margin. It is considered normal for the canvas to “sag” by 1-2 cm during installation. This is especially true when laying a vapor barrier on a roof or in an unheated room.

When installing vapor barriers in places with complex terrain (protrusions, corners, etc.), it is advisable to seal the adjacent surfaces with tape: perfect tightness in such places is difficult to achieve, and this is the main condition for the effectiveness of protection. Therefore, any aids will be useful. It is also necessary to tape the edges of the vapor barrier around the perimeter of door and window openings to ensure a tight seal. In general, tightness is the basis for high-quality vapor barrier of a bathhouse, roof or any other room. Therefore, when carrying out work, pay maximum attention to this aspect.

Features of "Alufoma" and "Tepofol"

The polyethylene foam base is “Alufom”, which has a one-sided coating of aluminum foil. The operating temperature ranges from -60 to +100 °C. Vapor barrier performs the functions of sound, hydro, steam and heat insulation, and also reliably protects against radon. It can be used for thermal insulation of roofs and floors. The wrinkled texture allows you to bend around curved elements of small radii without tearing the coating.

Foamed polyethylene is the basis of Tepofol, which in different variations has a reflective layer on one or both sides. The temperature effect can vary from -60 to +100 °C. This vapor barrier can be used for thermal insulation of air ducts, roofs and walls, as well as for the installation of heated floors.

Foil vapor barrier for a home must be completely safe, such as Izolon, which is environmentally friendly. The base is foamed polyethylene foam. The vapor barrier is vapor-tight, durable, and is distinguished by the flexibility and softness of the foil layer.

Nuances of fastening and installation

Installation of insulation is not difficult; it is easy to cut and install. The work on the outside and inside is almost the same.

Main nuances:

• the surface on which the insulation is placed must be clean;
• the material is straightened so that it is smooth, without wrinkles;
• foil prevents heat from escaping, so it is laid with the outer side up;
• the insulator is glued end-to-end, the joints are taped;
• If the insulation does not have a self-adhesive layer, use special glue.

It is important that the glue used for fastening does not emit harmful substances and holds the material firmly.

Walls

The slabs are mounted using dowels on vertical surfaces.
Installation of insulation to the wall must be thoroughly thought out. An air gap is left between the material and the subsequent finishing to avoid condensation.

1. The membrane is fixed and the insulator is rolled out on top of it.
2. The material is fixed with slats. Their thickness should be greater than the main insulation.
3. Along the edges of the slats, the insulator is connected with staples.
4. The panels are finished over the slats; their thickness provides the necessary air gap.

When insulating with mineral wool, a film is laid to prevent steam and moisture from getting inside.

Floor

The joints are sealed with aluminum tape.
Warm floors, regardless of whether the base is wooden or concrete, are made the same way.

1. Clean the floor of debris before applying insulation.
2. Cover the base with a primer.
3. After drying, roll out the insulation. The strips are laid overlapping and secured with construction tape. You can lay out a backing underneath the linoleum, which will make the floor much warmer.
4. A finishing coating is applied on top of the insulating material.

If laying a heated floor is planned, the insulation must be laid with the reflective side up, then the reinforcing mesh, heating elements and finishing cladding.

The choice of insulation materials is quite wide. Each of them has distinctive characteristics. Application depends on which room needs to be insulated.

Features of "Penofol", foil vapor barrier for the attic

If you need a foil vapor barrier for the attic, then you may prefer Penofol, which is based on a material with a thickness ranging from 0.2 to 1 cm. The thickness of the foil is 20 microns. It is also important to take into account the reflection coefficient, it is equal to 97%.

On sale you can find material for use in harsh climates, in this case the thickness of the main layer will be 40 mm. The foil layer also creates a barrier to heat transfer due to foamed polyethylene, which has a huge number of pores filled with carbon dioxide and air. Penofol can be used independently or in combination with other thermal insulation materials. It is especially useful if it is necessary to insulate the surface and not lose the usable area of ​​the room.

Installation technology

Most often, vapor barrier materials with foil are used to equip a cold attic and a warm attic. In the first case, the insulation system must be installed along the ceiling, in the second - along the slopes.

To install a vapor barrier correctly , you need to adhere to generally accepted construction rules:

1. The vapor barrier of the slopes should be a continuous barrier that prevents the penetration of moisture. To do this, the canvases need to be sealed together with regular tape.
2. Strips of vapor barrier material are usually laid strictly horizontally. The first panel is fixed at the ridge girder, the second is placed on top to cover the edge of the installed panel on the side of the room that is being finished.
3. The canvas spreads from the attic side onto the wooden floor in strips, extending onto the walls along with vertical ceilings of 20 cm each. It turns out to be a kind of pallet with sides.
4. Then the material is rolled out as if the roll was formed by the manufacturer himself. The installation side is indicated on the vapor barrier - it cannot be changed at your discretion.
5. On pitched roofs, the material is stapled to the rafters from the inside. If they are fixed with a block, then a counter-lattice must be placed on top under further cladding.
6. If you need to put a vapor barrier in a system with open rafters, then it is placed along the outer ribs, then rigid slab insulation is installed. The fabric is secured with a stapler.
7. If you are installing a ceiling on the ceiling side, then you need to buy self-adhesive materials.

It is worth noting that accessories for foil insulation must be selected from the same manufacturer as the material. Of course, you can find universal tape on sale that is suitable for joining materials of any kind, but in the case of foil structures, you need to remember about tightness. Therefore, here it is better not to experiment with options for adhesive tape for gluing, but to take it from the same company that produces the foil sheets themselves.

Additional solution for the attic: “Ondutis R Termo”

This material is used for thermal insulation of metal and wooden structures. When insulating an attic space or installing a roof in a residential attic, the film allows you to retain heat and reduce heating costs.

The water resistance of this vapor barrier is 1000 mm of water column; as for the minimum vapor permeability, this parameter is less than 10 g/m2 per day. The material easily endures temperature changes ranging from -40 to +120 °C. When considering strength, you should pay attention to the breaking load, which is 150 N along and 130 N across. This indicates that this foil film can support the weight of an adult.

Required materials and tools

There are several types of foil materials in the retail chain. Their installation requires different materials and tools. Therefore, we provide a complete list of the required set of tools, specifying when and where they will be needed.

Materials you will need:

• foil insulation;
• wooden beam 50x50 mm for lathing;
• spacer bar (20x50 mm) for installing a counter-lattice;
• plasterboard or OSB for covering the frame;
• primer;
• adhesive for insulation - individually for a specific type of substrate (“CERESIT CT 190” for basalt wool, “CERESIT CT 85” for foam plastic);
• metal corners, self-tapping dowels for the wall and wood screws - fasteners for assembling the sheathing.

The tools you should have on hand are:

• homemade sawhorses or stepladder (you can use a strong table);
• a hammer drill or electric drill - will be required when attaching the sheathing trim to the wall;
• screwdriver;
• mixer attachment for stirring glue;
• glue container;
• wood hacksaw;
• construction knife with replaceable blades;
• putty knife;
• level;
• roulette.

The main advantages of Penofol

Before purchasing Penofol, it is important to pay attention to its advantages, among them the following should be highlighted:

• high environmental friendliness;
• low vapor permeability;
• ease of installation;
• ease of transportation;
• insignificant thickness;
• noise absorption ability;
• high fire safety;
• inaccessibility for rodents.

Which side should the vapor barrier be laid on?

Depending on the base to be insulated, insulation material can be laid in different ways.

For external walls

The rough side of the product is placed against the insulation, the smooth side towards the street. Insulation of rough floor subfloors is carried out in a similar way.

Correct installation of insulation.

For under-roof space

The dark side of the product is laid outwards, the light side is placed towards the insulation.

On the basement floor inside the house

The product is placed on a rough surface towards the heat insulator.

For ceilings, external walls and partitions

The smooth surface of the film is placed towards the insulator.

Rules for laying on floors, external walls and partitions.

Polyethylene foam mounting side with foil

Foamed polyethylene is applied to the wall, another heat insulator.

The main disadvantages of Penofol

Some consumers refuse to purchase Penofol when they learn about its shortcomings. Among them:

• high penetration;
• inconvenience during installation due to the need to use special adhesives;
• Insulating walls from the outside with Penofol involves using the material only as an additional layer of thermal insulation.

As for high penetration, it will manifest itself even at low pressure; this characteristic is due to the softness of the material.

Advantages and disadvantages

The advantages include:

• the service life of the material covered with foil increases from 25 to 75%;
• in addition to heat insulation, it demonstrates sound insulation properties;
• allows you to reduce heat loss, which leads to savings in money spent on heating the room;
• when using thermal protection with foil (maximum material thickness 5 mm), space in the house is saved;
• simple installation method and affordable price;
• light weight of the material.

Flaws:

• For thermal protection of external walls, foil insulation alone is often not enough - additional material has to be laid;
• the impossibility of pouring cement-sand mortar over the foil layer;
• the high cost of metallized tape, which is required to hold together individual pieces;

• To install thermal protection with foil on vertical surfaces, you have to purchase glue, which increases the estimated cost of the work.

Types of foil vapor barrier in the form of film

Foil vapor barrier for walls can be represented by film. It is able to protect the insulation from moisture that penetrates from the premises. If you use such a vapor barrier in a bathhouse, then the inner lining can be reliably protected from rot and mold that appear due to condensation after the steam room is turned off.

Such a foil reflective vapor barrier will reflect heat, and condensation simply will not settle. The film can be made from kraft paper; this option is inexpensive, easy to handle, hygroscopic, and quite easy to tear.

Vapor barrier can also be made on a polymer basis, in this case it is durable and strong, but will cost more. If there is aluminum coating on the surface, then the thickness will start from 0.3 microns, however, as the thickness of the coating decreases, the heat-reflecting abilities will deteriorate.

Foil vapor barrier for frame walls can have a base made of aluminum foil. In this case, the thickness of this layer will start from 10 microns, which will guarantee the maximum level of reflection. Such materials are susceptible to corrosion and therefore require additional protection. Experts advise insulating the walls of rooms with high humidity using aluminum-coated polymer-based foil films, since they do not corrode and can withstand high temperatures. They are durable, which greatly simplifies installation.

Films based on kraft paper can only be used in dry rooms; they cannot be used in bathrooms or kitchens. For heated floors, it is recommended to purchase a film with aluminum foil, which distributes heat, smoothing out cold bridges if the pipes are not laid tightly enough.

Principle of operation

Foil materials are a complex product with a layered structure. The base here is polypropylene fabric, fiberglass, and lavsan. These are components that are resistant to explosive effects, biological and chemical aggression.

The use of a durable non-woven or woven polymer base allows you to create a reliable base for metal foil, which itself cannot boast of particular strength. At the same time, flexibility convenient for installation is maintained. This composition eliminates the possibility of fungal colonies settling and rotting.

Vapor barrier materials on the working side are backed with metallized film. The positive qualities of both aluminum foil and the polymer base are preserved. Vapor barrier with foil copes with three tasks at once:

1. Insulation from precipitation and steam. The foil material protects the wall insulation system or roofing pie from steam penetration.
2. Reflection of thermal radiation. The metal coating serves as a kind of reflector; it interrupts the flow of heat waves, redirecting the stopped heat within the house.
3. Protection from ultraviolet rays and wind. Vapor barrier films are a durable barrier against wind. In the summer, they are able to reflect the sun's rays from the roof if they are installed with the working side facing outwards.

Varieties of "Penofol"

"Penofol" can be classified by type:

• A.
• IN.
• WITH.
• ALP.
• R and M.
• Super NET.
• AIR.

In the first type, the aluminum layer is applied only from the outside; this material is used in conjunction with polystyrene foam and styrodur. Type B is coated on both sides and is suitable for independent use. Type C is a self-adhesive material in which the outside is covered with foil, while the inside is polyethylene foam with contact adhesive.

ALP is “Penofol”, on top of the aluminum layer of which a polyethylene film is fixed. This material is laminated and can be used for needs in rural areas. One-sided foil embossed material are varieties R and M. But “Super NET” is used for thermal insulation of networks. The latter variety is suitable for air ducts.

Price

in the production of foil insulation on the Russian market :

• Jermaflex;
• Izolon;
• Penofol;
• Tepofol;
• Folgoizol;
• Ecofol.