The standard set of protective materials for the walls of the house includes insulation and waterproofing. The first regulates the temperature, and the second does not allow the passage of moisture. But in the “work” complex, two layers can form condensate, which adversely affects both the insulation material and the protected base. To eliminate such phenomena, vapor barrier of the walls helps, which delays and prevents the spread of water vapor.
The principle of operation of the vapor barrier
To understand how a vapor barrier works, you should turn to the concept of “dew point”. This is the temperature level at which moisture goes into a dew state - that is, the process opposite to evaporation. For this phenomenon, a combination of several microclimatic indicators is necessary, with which the insulator works. At home, the level of humidity and temperature is always higher than street temperature, which determines the desire of moisture to go outside. This process just leads to condensation on the walls of the house.
Here it must be emphasized that moisture is not only directed naturally upward, but leaves through any cracks and gaps in the building frame. And even a heater with a waterproofing insulator cannot act as a complete obstacle to this process. How does vapor barrier at home help? This layer, thanks to the sealing function, creates the conditions for moisture to come out with minimal losses, without leaving condensate (dew) on building materials and insulation.
Vapor barrier film
The most common material for providing the vapor barrier function is film. On average, such insulators maintain a throughput of 0.5 g / m2 per day. That is, there is no talk of perfect sealing, but the film fully provides protection of walls and structures from direct steam exposure with the consequences of dampening. Manufacturers produce film vapor barrier walls in yellow, green and blue colors. Depending on the conditions of use, it is possible to use materials with reinforcement, that is, a reinforced structure, if there are threats of mechanical damage. Expensive film insulators have a fiberglass treatment that improves both external resistance and tensile strength.
PVC membrane for vapor barrier
There are a lot of options for combined insulation on the market, in which hydroprotection and a vapor barrier are combined. Such coatings are characterized by a thick structure and multifunctionality. One of the layers of hydro vapor barrier is a membrane. It effectively regulates the passage of water vapor, and also protects the adjacent insulation from moisture.
But there are also separate membranes made of polyvinyl chloride (PVC), which can be used as an independent protection against water vapor. If you plan a completely tight vapor barrier inside on the walls, then it is quite possible to give preference to polymer membranes. The fact is that they are not fixed by a standard sheath or hardware along the edges of the waterproofing, but by means of a heat pile. The molten material eliminates gaps and gaps in the insulation structure. In other qualities, polyvinyl chloride is also not inferior to a conventional vapor barrier film. Its top layer is protected by a textured coating that gives the material strength and resistance to damage. The main composition includes modifiers and additives that improve the susceptibility of high temperatures and UV rays.
How to choose the right material?
Despite the same function and principle of operation, materials for vapor barrier are not the same. There are various characteristics that you should rely on when making your choice. One of the main ones is protective qualities. We are talking about mechanical protection, which is provided by the already mentioned reinforcement layer, foil and other coatings. Next, pay attention to durability. This is a complex parameter that depends on the internal structure of the material, resistance to aggressive environments, physical influences, etc. What is more important, is the compatibility of the vapor barrier of the walls with related materials that regulate temperature and humidity. Docking with metallic coatings is completely excluded, as is the combination of synthetic and natural organic insulators. It is advisable to select a film or membrane from the series of one manufacturer.
General recommendations for the installation process
Before insulating work, the general structure of materials regulating the microclimate of materials should be considered. As a rule, vapor barrier is placed between thermal and waterproofing. That is, it separates a humid environment and a dry, retaining heat. The most important task during installation is to ensure high-quality fixation. There are different ways of fixing the material, due to its structure and operating conditions. The simplest method is using self-adhesive strips that the manufacturer himself applies to the surface of the insulator. Such installation of vapor barrier of the walls has disadvantages in the form of low strength and fragility, but with tight clamping from the side of the heat and hydraulic panels, it can justify itself.
As already noted, to ensure maximum sealing effect, it is better to use membranes that are laid and fixed by heat welding. But this option will require the use of special equipment, not to mention the burner handling skills. As for the use of traditional fasteners, this option is suitable when performing vapor barrier walls from the inside, where third-party damaging factors will not affect the film. Rigid fixing of a self-tapping screw or screws with screws in combination with retaining profiles is, of course, more reliable, but there is a risk of tearing at the very passage line of the mounting elements.
Which side to install the insulator?
The fundamental issue that determines the most effective configuration for the placement of vapor barrier material. If glassine is used as an insulator, then it is better to lay it with the inside to the insulation. Bituminous black surface should be facing the room. A simple single-layer film is fixed by either side to the heat insulator. It does not have pronounced protective properties with the exception of reinforcement, but even in this case, the reinforcing fibers equally support the strength of the overall structure. But there is also a special fleecy vapor barrier of the walls. Which side to attach it to? These are two-layer materials that are installed tightly to the insulation with a smooth surface, and the pile turns outward. Almost all metallized and foil coatings are attached with their protective side to the room. The same foil will act as a mechanical barrier and a heat reflector, so it focuses on external space.
Steam insulation technology inside
The requirements for decoration in the room are not as high as on the outside. It is enough to think over the components of the insulating “pie” and make the installation. For frame houses, it is recommended to use a construction stapler for fastening. It allows you to reliably fix the thin layers of insulation, hydro- and vapor barrier. Installation should be done to the harness or to the racks of the frame. The wall material itself should not be mated to the mount. According to experts, proper vapor barrier of the walls does not allow dense mixing of two protective layers. It is for the effective removal of condensate between the hydro- and vapor isolator that a small gap should remain for ventilation. By the way, for this purpose, manufacturers of film materials do not provide absolute sealing to the materials, leaving air tolerance.
Outdoor vapor barrier technology
The problems of isolating the house from the outside are a whole complex of threats that affect the facade. Therefore, proper physical protection is indispensable. A frame structure is formed, including a crate. Its skeleton is made of a metal profile or wooden bars with counter-rails. It should be noted that outside the vapor barrier of the walls is arranged in two layers. The first fits under the crate. It is enough to glue the edges of the material, and fix the wooden or metal frame from the outside. In the niche of the crate, heat insulating plates and hydroprotection are placed. This is followed by a closing counter-battens with panels on which a second vapor barrier layer is laid. Installation is being completed by the facade cladding.
Features of vapor barrier of wooden houses
Solid wood is more susceptible to adverse effects of moisture and condensation. Dampness is a direct factor due to which the processes of biological destruction of walls begin with the appearance of fungus and mold. How to perform vapor barrier for the walls of a wooden house? The structure of the insulation system will be the same, and the difference lies in two points:
- Laying the vapor barrier must be comprehensive. It is necessary to isolate not only walls, but also floors with a ceiling structure, an attic and other surfaces of the house. If the process of decay begins in one damp corner, then in the future we should expect its development in places protected by the insulator.
- Prior to installation, a comprehensive treatment of wood with protective impregnations should be carried out. It is also necessary to seal the log structure, since “cold bridges” often trigger the destruction of material that is constantly under cold and in damp.
Joint Processing
Laying can be done end-to-end and overlap. It depends on the mounting method and the type of insulator itself. At the final stage, after the installation is completed, it is necessary to examine the coating for the detection of insufficiently sealed areas. These are not technological tolerances for air circulation, but clearances left as a result of a technical error or improper installation. How to eliminate such defects? The choice of materials for embedding depends on the design itself. For example, vapor barrier of wooden walls can be carried out with the addition of viscous mixtures with butyl rubber, polymer compositions and butylene. On the contrary, cracks on flat surfaces are recommended to be removed with hard mats and panels. Foamed polyethylene products are usually used, which also strengthen the insulating “pie”.
Vapor barrier manufacturers
There are a lot of means of insulation and water protection on the market, but a specialized barrier for water vapor is a narrow segment. The best known brand in Russia is Izospan, which offers tools for external and internal protection. The main thing is to choose the right marking. For example, vapor barrier for the walls of a wooden house can be carried out by means of Izospan B. Axton offers several options for vapor protection - in particular, a non-woven membrane is produced for building structures that protects surfaces from moisture and steam. Premium materials are developed by the American company Tyvek, focusing on external protection. For complex insulation, combined wind and vapor barrier films are recommended.
Conclusion
The targeted device of the barrier against the passage of water vapor has become fashionable not so long ago. Previously, such functions were entrusted to waterproofing and a thick plastic film. Today, reliable vapor barrier of the walls can be ensured at the lowest cost with the thinnest layers of polymeric materials. And again, do not forget that the walls are only part of the frame, the protection of which will not matter without proper insulation of adjacent structures. Another thing is that in each case, an insulator with suitable characteristics, protective properties and optimal throughput is selected.