For many owners of private houses and developers, it is a problem to determine how to properly install a vapor barrier on the ceiling. Such an insulation layer is needed to protect the insulation from moisture from the side of the room (for example, household fumes).
Moisture worsens the thermal insulation properties of the material, therefore, a special barrier is arranged in its path. As a rule, such work is performed by professionals. But the developer himself needs to know the basics and how the vapor barrier is subsequently operated.
Why do i need
It’s not enough to know how to properly install a vapor barrier on the ceiling of a bathhouse or a living room, you still need to understand why this is done. Many believe that if they do not plan to make a heated room out of the attic, then neither steam nor thermal insulation is needed. In fact, both of them are still necessary, if only in order to reduce heat loss.
Just with an unheated attic, the insulating layer can be laid directly on the reinforced concrete floor or placed in the space between the wooden logs.
But regardless of this, it is necessary to lay a vapor barrier material under the thermal insulation layer. It prevents the penetration of steam into other elements of the roofing cake, which is especially important for rooms with high humidity, including a bathhouse or kitchen.
Due to the presence of this layer on the wooden elements of the frame, mold does not appear and the fungus does not develop.
How will the vapor barrier be located
Which side to properly install the vapor barrier on the ceiling and what is the layout of this layer, excites many when installing a roofing cake. In fact, everything here depends on how the attic is used.
If the unheated room and space do not plan to be used somehow, then the material is laid only on the ceiling plane. In this case, the insulation does not need additional waterproofing or wind protection, although the hydrobarrier along the slopes is still arranged so that atmospheric precipitation does not penetrate.
If the attic will be used for storage of things, for some household purposes, including drying clothes, then the insulation in the roofing pie must be closed with vapor barrier on both sides. On pitched planes, they still do waterproofing.
Types of materials
Different types of materials are used for vapor barrier, including:
- Film. This is the simplest and cheapest material. They produce it in rolls, based on viscose and cellulose fibers. The material has a porous structure, which made it possible to retain excess moisture. Film thickness can vary between 10-200 microns, width - 2.5-6 m. The material is suitable for cladding both wall and ceiling surfaces. This is a fairly practical and reliable option for vapor barrier. The material can withstand high temperatures and humidity. Therefore, the correct installation of vapor barrier on the ceiling in the bath often involves the use of film material. But he has his flaws. This is mainly relative fragility. In addition, if high temperatures last for a long time, it can be destroyed. Therefore, for the steam room itself is usually not used, only for other rooms in the bath.
- Kraft paper. It is a construction cardboard with a protective coating, most often - foil, less often - lavsan (such material is more expensive). It is mainly used for vapor barrier in rooms with normal humidity. It can be used in the bath. But only for the rest room, not for the steam room.
- Membrane materials. Considered the most popular option. Their distinctive feature can be considered a special two-layer structure. In it, each layer performs its function - one prevents the penetration of fumes, while at the same time, the second provides air circulation.
- Lubricants. This group includes polymer-bitumen mixtures produced under industrial conditions. They can be used even for rooms with high humidity. After application, they polymerize, which makes it possible to obtain a durable wear-resistant vapor barrier layer that provides maximum protection against evaporation, and in addition has high noise and heat insulation characteristics.
Sometimes foil materials are isolated in a separate group. In addition to the already mentioned variety of kraft paper, it is also vapor barrier made of fiberglass and some other options.
The best vapor barrier materials
Despite the abundance of a variety of insulating materials, most often in private construction, homeowners give preference to two brands - Izospan and Dekker.
Despite the fact that they are produced using different technologies, they have one common property - ease of installation, which is often a key factor for such construction.
Izospan and its properties
Most often, in private low-rise construction, membrane materials are used as the most practical and simple to install. One such option is, for example, Izospan. This is a special film on a polymer (more precisely, polypropylene) basis.
Films of different thicknesses and, accordingly, different degrees of strength are produced. In any case, they provide effective protection of the insulating material from the damaging effects of moisture.
The company produces several types of material: FS, FX, FB. In the first case, we are talking about a polypropylene-based membrane on which metallized spraying is applied, in the second - on foamed polyethylene, in the third - on a foil insulator made from kraft paper.
The choice depends on the purpose of the room itself.
Decker vapor barrier materials
Decker REFLEXX Aktiv materials are considered good vapor barrier. They are used where energy efficiency is important and it is planned to install a thermal insulation layer with a thickness of 250 mm or more.
Instead of the traditional aluminum foil coating, a special spraying layer with a high reflectivity is used here. It is not susceptible to oxidation, increases the vapor and heat insulation properties of the material.
The Decker Klimat Aktiv vapor barrier has also worked well. It does not have a reflective layer, but it also has the same good characteristics.
Many are interested in how to properly install Decker vapor barrier on the ceiling. In general, the process occurs according to the algorithm described below. But special tapes are used to glue the material.
In no case should you take household adhesive tapes, only intended for professional use and branded. Ordinary can peel off pretty quickly.
Mounting technology
Laying vapor barrier on the ceiling requires an integrated approach. This is the only way to prevent heat loss and protect roofing materials from moisture. Regardless of what type of insulation material is used, such work is carried out in several stages.
How to lay the vapor barrier on the ceiling:
- Training.
- Installation of waterproofing material.
- Laying a heat-insulating layer.
- Installation of vapor barrier.
- Final surface cladding (performed for decorative purposes).
Each of these stages has its own characteristics, taking into account the type of material used.
How to install film and membrane materials
Before you put the vapor barrier on the ceiling, you need to carry out preparatory work. If this is not just an unheated room that will not be used, but an attic, then preparatory work will take more time.
After all, you need to clean the surface of the base from dust and debris, level it, covering the cracks with the appropriate compounds, and then primer and dry this plane.
Preparatory work
Sometimes preparatory work involves more operations. For example, if necessary, it will be necessary to repair the beams of the ceiling. It is especially true for houses that have long been in operation - in this case, it is necessary to check the integrity of all elements, carry out repairs, remove all traces of fungus and mold.
All wooden elements are treated with a fire retardant and fungicidal agent to prevent infection by microorganisms. This is equally important for both old and new homes. At the same stage, all work on the installation of utilities is carried out.
Installation work
The algorithm for installing film materials is as follows:
- The film is pre-cut according to measurements, mounted on the ceiling with an overlap of strips (its value is 10-15 cm, not more), and then fastened using a construction stapler.
- The film is laid with the clean side to the insulation, the side with the logo will be on the outside.
- For joints to be strong and reliable, they use a special waterproof tape (for example, there is a good tape brand "Ondutis"), and those places that adjoin directly to the passage elements need additional insulation. They are also glued with tape, but with higher characteristics.
- The vapor barrier film is laid loosely so that it does not stretch, even if the material sags slightly - it’s even better because it will provide a margin of safety in case of a sharp temperature drop.
- Wooden bars are installed on top of the film.
When everything is ready, you can begin decorating. Membrane materials are laid in a similar pattern.
Laying vapor barrier in the bath
In this room, with a combination of high temperatures and humidity, vapor barrier is especially important. Moreover, such work is carried out both for the ceiling and for walls and floors. Additionally, surfaces can be treated with protective compounds.
But only a few know how to put vapor barrier on the ceiling in the bath. Such work is usually carried out in the following order:
- Preparing a log ceiling. To do this, it must be sheathed with boards (recommended thickness - 6 cm). A foil material is fixed on top of such a crate (a thickness of 100 microns is sufficient).
- A uniformly softened clay is applied to the foil layer and laid on top of the selected vapor barrier material.
- Heat-insulating material is laid on the layer described above; mineral or basalt wool is usually used for a bath (recommended thickness is 5 cm). Seamless insulation is sometimes recommended. In such cases, choose ecological wool or expanded clay.
- A moisture protective membrane is still installed on the insulation layer, which is an additional preventive measure.
In the bathhouse, a vapor barrier of the roof is also carried out, that is, the insulation is closed from moisture on both sides.
Laying vapor barrier: important points
Proper installation of the ceiling insulation requires knowledge of some of the nuances of working with such materials.
First, you need to protect the vapor barrier, in no case should you pierce such material with nails. In order not to damage it, the stapler and ribbons mentioned above are used.
Secondly, a ventilation gap of at least 5 cm should be provided between the film or membrane material and the decorative finish. This is important for rooms with high humidity, as well as for country houses that are not constantly heated in the cold season, but periodically.
At the same time, where the vapor barrier material intersects with the chimney, you need to take care of the tightness of the joints. Then the whole system will last a long time and will be quite effective.