Home insulation is carried out using modern materials. This allows you to reduce heat loss and the cost of paying utility bills in the cold season. One of the common materials that are used when arranging a heat-insulating layer is vapor barrier. It has certain properties. Why vapor barrier is needed, the features and varieties of this material will be discussed in detail below.
General definition
Why do you need vapor barrier? This question often arises among novice builders, landlords, and apartment owners who decide to make their own repairs. If thermal insulation is required, several different materials are used. Their choice depends on the characteristics of the operation of the facility, the tasks of the insulation, as well as the budget for construction and repair work.
It is worth saying that with improper installation, work will need to be redone in the next few years. In order for the insulation to perform the functions assigned to it, it is often required to apply vapor barrier. This is a special material that performs certain functions.
The fact is that the humidity level in the room can change under the influence of various factors. And with temperature differences, condensation may appear not only on the walls, but also inside the thermal insulation layer. This is due to a certain ratio of humidity and temperature at which the dew point moves inside the room. Because of this, condensation forms.
Almost all building materials let steam through. This process does not affect only glass, metal. Inside and outside the room, steam can be converted to condensate at a certain temperature. It falls most often inside walls, roofs, accumulating in the structure of the heat-insulating layer. Many heaters, saturated with liquid, begin to pass heat from the room. As a result, the room will have to be heated more often, spending additional expensive energy resources.
Water inside the insulation can freeze in severe frost. It irrevocably destroys its structure. And when the warming comes, the ice will melt. Water will begin to leak through the walls, overlapping the inside of the room. The interior decoration in this case will be irreparably damaged. To prevent such negative consequences, vapor barrier is used. Its main purpose is to prevent steam from the premises inside the insulation. Vapor barrier shifts the dew point. This prevents the destruction of thermal insulation, the formation of mold on materials, which, in turn, extends the life of wooden structural elements. They will not rot. Therefore, vapor barrier of a wooden house is necessary. For other buildings, its use is also necessary.
The difference between vapor barrier and waterproofing
Do you need vapor barrier when warming a house? The answer is yes in most cases. However, you need to understand that this material is slightly different from the usual waterproofing. The structure of these foams is not the same. Vapor barrier is needed to protect structures and insulation from vapors that form inside the house. The film may have different bandwidths.
Some types of vapor barrier have pores. This is a layered material. Each of its components performs certain functions. Waterproofing does not possess such qualities. This is a permanent material through which steam or water does not pass. Therefore, waterproofing is used to protect walls, roofs from moisture from the outside. Rain and snow may fall on these structures. Waterproofing does not allow water to enter the walls, roof, foundation, etc.
Another purpose of waterproofing is to prevent the ingress of water, which can seep through the soil to the foundation. Therefore, waterproofing is used to create the foundation. It protects the construction of the base of the house from the "overhead" during the melting snow or with heavy rainfall in the autumn.
Taking into account the facts presented, one can answer whether a vapor barrier is needed outside the building. When creating a layer of insulation, both types of materials are needed. Just the sequence of their installation will be different.
Varieties
Studying the question of whether vapor barrier is needed in the house, it should be noted that this material should be used when creating a layer of insulation. However, for the film to perform the functions assigned to it, one should acquire a suitable variety. There are several options for vapor barrier. They differ in operational characteristics and scope. The following vapor barrier categories can be distinguished:
- Roll films that can be impregnated with different compositions.
- Liquid coating.
- Sheet adhesive vapor barrier.
- Polyethylene films.
- Foil materials.
- Membranes that are able to pass a certain amount of steam (able to "breathe").
Each of these groups has a specific area of ​​application. Therefore, you need to understand for what purposes the material is acquired. Otherwise, he will not cope with the tasks assigned to him.
Impregnated roll materials have bitumen or the like in their structure. They are acquired to create temporary isolation. It should be borne in mind that the installation of this material is quite problematic. Joints can only be sealed with a gas burner.
Coated varieties are quite expensive. They are used to create the floor in the bath, bathroom. Adhesive-based materials are more suitable for creating a vapor barrier layer at the places of installation of communications or at the joints of building materials. Completely cover the surface of the walls, the ceiling is expensive. And hard enough.
Polyethylene film
Considering why vapor barrier is needed, it should be noted that its use is extremely necessary in rooms with high humidity. However, in dry residential premises it is necessary. Polyethylene films are on the market. This material from all of the listed options is the most inexpensive. Therefore, it is often purchased. But it is worth considering that not in all cases this type of vapor barrier is applicable.
Polyethylene films can be mounted on the base by either side. Due to the nature of the structure, the scope of this material is limited. Most often, such a film is suitable as a temporary wind protection, and also prevents the penetration of precipitation into the structures. Condensation may appear on the surface of such a film under certain conditions. Therefore, such materials require proper installation.
The life of the plastic film is limited. It quickly collapses under the influence of external factors. If you want to install a high-quality thermal insulation layer that does not require replacement for a long time, it is better to give preference to other types of vapor barrier. It is advisable to lay polyethylene films on the base when creating a concrete floor.
Membrane type vapor barrier
Considering the recommendations on whether it is necessary to make vapor barrier in an apartment and a private house, it is worth considering another type of materials. These are membranes. They are capable of transmitting steam with greater or lesser intensity. These are multilayer structures that have the ability to "breathe". Each layer performs certain functions.
Each layer has holes through which droplets of vapor pass further. To the process was one-sided, the holes have different diameters. In the first layer, the pores are minimal. This is necessary in order to cut off part of the moisture, not to let it inside the insulation structure.
Some types of membranes have reinforcement. It does not allow the material to deform under temperature fluctuations. This significantly extends the life of the vapor barrier. However, reinforcement is not found in all membranes. This must be considered when choosing a material.
The third layer has pores whose diameter is larger than in the first layer. This allows air to flow in one direction. This configuration promotes quality traction. Water will not stagnate in the material. This layer may be roughened. Using such a material, you need to know whether a gap is necessary for vapor barrier. Between it and the main finish, a gap should be left, the width of which should be at least 2.5 cm. Water stagnates in a natural rough layer. It should be diverted naturally. This provides ventilation clearance.
Combination of vapor barrier with heaters
Experienced builders argue that the use of vapor barrier in some cases is completely optional. In order to find out whether such material is needed in a particular case, it is necessary to determine with what heaters the film is necessarily used.
On sale are many options for thermal insulation. If the insulation is porous, able to absorb moisture, its performance is markedly reduced. These varieties are primarily mineral wool. This popular insulation when wet is not able to retain heat inside the building. Therefore, it is worth creating a vapor barrier layer for it.
Many novice builders are interested in needing vapor barrier foam? This is a heater that is created on a synthetic basis. It repels water and is not able to let steam through. Therefore, it may seem that vapor barrier is not required for such a material. However, it is not.
Steam is a substance that can penetrate even the smallest gaps. Sheets of foam are mounted on the surface of the base on glue. Under them remains a small air gap. Under certain conditions, condensation may accumulate in this gap. Over time, a fungus will develop here, rotting processes will appear. Steam penetrates through the cracks between the plates of insulation. To prevent this process, it is worth purchasing a vapor barrier.
A film is not required if foamed polyurethane foam is applied to the surface of the wall. This material is so close to the surface that no air gap forms under it. In the structure there are not even minor gaps. Therefore, the walls will be reliably protected from steam and condensate.
Film for the balcony
Knowing why vapor barrier is needed, it should be noted that for different rooms, as well as surfaces, this material is required to a greater or lesser extent. So, often vapor barrier is used when creating a layer of insulation on a balcony or loggia. Here you can’t do without it.
The loggia is a barrier between the house and the street. It is here that due to temperature changes, condensate most often forms. The area of ​​windows on the balcony is significant. It is glass that is distinguished by a low temperature. This contributes to the spread of moisture inside the insulation layer. To prevent this from happening, you need to use the correct vapor barrier.
The film should not be just a three-layer membrane. It should have a layer of foil. In this case, she will most effectively cope with the tasks assigned to her. The foil will further prevent the loss of infrared rays. Heating a loggia or balcony in this case will be much more efficient.
Considering the question of whether vapor barrier is needed when warming a house, you should find out the nuances of carrying out similar work for its various constituent elements. They may differ when creating thermal insulation of walls, roofs, floors, etc.
Walls
Do you need vapor barrier walls? The insulation in this case can be mounted both inside and outside the room. If the insulation layer is mounted from the side of the room, vapor barrier in most cases is needed. Especially important is its use for brick, concrete walls. Here, the probability of condensation stagnation is higher than that of wooden structures. Therefore, the use of a membrane in this case is necessary. However, with an increased level of humidity for wooden walls, it is required to use protective films for internal insulation.
With internal insulation, the dew point shifts. Condensate in this case may occur precisely in the structure of the insulation. It is possible to refuse the membrane only if external insulation was performed, and indoor insulation performs an additional function.
When creating a layer of insulation from the outside, vapor barrier is not needed. No steam is generated here. If it does appear, then it does not penetrate deep into the structure, being excreted naturally. Only when decorating the bath outside requires the use of a membrane.
Floor
Do you need vapor barrier in the house when arranging flooring? The answer depends on the characteristics of the room. It is recommended to use membranes for the floor on the balcony. At the same time, no film is needed for interfloor ceilings. Only waterproofing is used here.
An exception can only be the premises of baths, saunas, showers. Here the steam is much larger, so the use of a membrane will be appropriate.
Roof and ceiling
Do you need a vapor barrier of the ceiling and roof. The answer is definitely positive. Steam always rises. It is the ceiling that takes the brunt. Even in a dry room, when installing a heater, a membrane is mounted. Moreover, it is installed first. A heater is already attached to it.
For the roof, the membrane is also extremely important. It is installed from the attic or attic. Next is the insulation. Waterproofing is mounted on it. The top layer is roofing material.
Having considered why vapor barrier is needed, you can make the right decision about the appropriateness of its use in certain conditions.