When building a house, the issue of vapor barrier overlap does not initially arise. The homeowner begins to think about this problem when it comes to warming the room. It turns out that not all home masters know how to equip a vapor barrier layer. It is also important to decide which material to use for this. Indeed, a simple film, for example, is used less and less today.
The need for vapor barrier in the ceiling
Vapor barrier for the ceiling in a wooden floor is necessary. This will prevent the penetration of vapors into the insulation layer. Materials will be protected from the damaging effects of moisture. This will avoid contact of moist air with a heater. If you neglect these rules, then it will be covered with mold, as well as fungus. At the same time, the entire construction will serve much less. After all, structures must be reliably protected from negative influences.
The presence of a vapor barrier layer allows not only to protect materials from water, but also to reduce heat loss. If coatings with a foil layer are used, they will reflect most of the heat, sending it back to the room. But humid air can freely go outside. The main task of such a coating is to protect the thermal insulation from moisture accumulation in it.
Material selection
Before you will be able to carry out vapor barrier for a ceiling in a wooden floor, you must purchase the material, taking into account the budget for the work, as well as the goals. Based on this, we can distinguish the following materials:
- polyethylene;
- films with a membrane effect;
- glassine;
- varnishes;
- mastics;
- foil materials.
If we are talking about films with a membrane effect, they will not allow moisture to pass inside the premises. Among other things, they prevent it from going out. Varnishes and mastics have the same effect. But one of the cheapest materials is glassine. Quite often, experts do not advise using ordinary plastic film for the installation of a vapor barrier layer. It is used only in the most extreme cases. Such a coating will not allow air to pass, turning the building into an airtight box. At the same time, the rooms are not ventilated, condensate accumulates on the surface of the film. As a result, moisture settles indoors, causing mold and mildew.
Suppose you decide that you need a vapor barrier for the ceiling in a wooden floor. In this case, glassine can be used only if there was not enough money for a better material. It is not durable. They choose it most often for the reason that it has a low cost. According to experts, the best solution is vapor barrier based on liquid mastics or membrane films. With their help, it is possible to reliably protect the floor, providing the exit of wet vapors to the outside.
Recommendations for installing a vapor barrier
The vapor barrier for the ceiling in the wooden floor must not only be correctly selected, but also installed according to the technology. As a rule, the material is placed indoors. If the temperature drops during the cold season are large enough, and frosts reach below 30 ° C, then vapor barrier is installed on both sides. This will eliminate the occurrence of condensation in the thermal insulation and save more heat indoors. But that is not all. It should be remembered that the vapor barrier must be laid on the ceiling until the moment you arrange the insulation layer. The canvases are stretched without sagging or wrinkles. Neighboring pieces overlap. All joints are glued with construction tape, which allows for air passage.
Vapor barrier - a film that is fixed with special nails with a wide hat. Such fasteners can be replaced with brackets of a construction stapler. Under them should be laid gaskets made of cardboard or any other similar material to prevent tearing of the film. The step between the attachment points should not be more than 30 cm. When the film is planned to be hemmed to the rough floor, fixing is carried out using metal profiles or crate elements.
Quite often, home masters think about how a vapor barrier is installed correctly. Which side to lay this material, it is important to decide before the start of work. Thus, the smooth side of the film should face outward, in the direction of the rough overlap. If mixed up, then you can get the opposite effect. It lies in the fact that water vapor will settle inside the thermal insulation. This will certainly lead to the destruction of the material. A small gap should be left between the vapor barrier and the roofing material. This is true when the vapor barrier is planned to be laid on both sides. This approach will allow the circulation of moist air and freely go outside.
Installation Specialist Tips
When laying a vapor barrier layer, it is necessary to exclude the presence of holes and gaps between the sheets. This will protect the thermal insulation and structural elements of the building. If you apply sheet vapor barrier, then laying is carried out from the roof. The material is located under a layer of insulation after its full installation. Outside should be another layer of vapor barrier. This will guarantee the best protection for the insulation. Liquid vapor barrier for the ceiling is applied externally to the previously prepared structure. After the first coat has dried, two more should be applied with a gap for complete drying. It is better to carry out such work in warm weather. It is important to wait until there is rainfall.
During the construction of any house, vapor barrier is required . Which side to lay this material, you should ask at the initial stage of the work. For example, foil cloths are quite actively used today for a vapor barrier layer. They have one advantage, which is the ability to reduce heat loss. To do this, the foil side should be facing inside the room so that the heat goes back to the house.
Reviews of standard vapor barrier for the ceiling
If you still think what vapor barrier to choose for the ceiling of the house, then you should listen to the opinion of property owners. They argue that the standard will work correctly if you place it on the inside of the building envelope. Water vapor will not pass into the ceiling and to the insulation. The most common materials of this type are: TechnoNIKOL, Izospan, and Ecolife.
Reflex layer vapor barrier reviews
Vapor barrier - materials that can be combined into one group. As one subspecies, we distinguish variants with a reflex layer. According to users, they have a reflective effect. Do not let steam pass, radiant heat goes into the room. They perform the function of additional thermal insulation. Their use, according to home masters, is most effective when increased steam formation is noted. The most widely used are Penofol and Alucraft.
Controlled permeability vapor barrier reviews
If you wondered what to use for vapor barrier of the ceiling, then you can consider materials with limited permeability. As buyers emphasize, this approach is rational when housing is not constantly operated. This includes country houses. The vaporization cycle is not stable. And after the departure of the owners when arranging a vapor barrier layer with limited permeability, the steam will go outside. According to customers, such membranes are able to maintain the desired level of vapor barrier. Their permeability is Sd = 2–4 m.
Variable permeability vapor barrier reviews
This type can be used when repairs are carried out in the area of the attic floor. With this approach, the vapor barrier can only be laid on top, while the ventilation gap is not equipped. The permeability coefficient in this case varies within 5 m, which is true for a dry membrane; if we are talking about wetted material, then the mentioned parameter is 0.2 m. Most often, consumers choose Delta-Sd-Flexx, which refers to this type of vapor barrier.
Membrane Reviews
Membranes are considered a new type of vapor barrier materials. According to customers, they serve as a vapor and hydro barrier. If we compare them with films, then the latter do not let water and steam pass, which is completely independent of the direction. If we are talking about membranes, they are characterized by unilateral permeability. This indicates that it does not matter at all which side to lay them on. Property owners emphasize that steam will pass through the material, while water will not be able to leak towards. It is noteworthy that the membranes can be single, double and multilayer. The most economical is the second option. Moreover, the effectiveness in all cases remains at the same level.
The cost of vapor barrier materials
Vapor barrier is a film that can be produced by different companies. If we are talking about the waterproofing material of the Izospan company, then the variety indicated by the letter B will cost the consumer 1,000 rubles. If you want to choose the Isospan A wind-proof membrane, then you will have to pay 1,500 rubles for it. On sale you can also find goods to protect the material from steam and water. If it has the name "Izospan D", then you will have to pay 1,400 rubles. Vapor barrier for a ceiling in a wooden floor, the price of which is 1300 rubles, can also be represented by a reinforced film. If you prefer this variety, then you can consider Polinet Lux, which has the following dimensions: 2x25 m.
Conclusion
The types of vapor barrier for the ceiling were considered above. Depending on your budget, as well as your goals, you can choose one of them. It is not always advisable to save, because, for example, an ordinary film may not fulfill the tasks assigned to it.