Exposure to moisture adversely affects the state of wall and floor structures, therefore waterproofing is performed as a mandatory measure of their protection. At the same time, in some rooms, such as basements and attics, condensate can accumulate, emitting water vapor. Its impact on building materials is also negative, although not to such a high degree. Comprehensive sealing of structures could eliminate all sorts of problems due to contact of building materials with moisture. Partly such problems are solved by vapor barrier. This is a material that regulates the vapor permeability, protecting the target surface or even the room from destructive processes. How to install a vapor barrier? Installation and fastening of the coating is carried out in several technological stages. In the course of work, the features of the selected insulator and the conditions for its future use are taken into account.
What is a vapor barrier?
Most often, this film material is yellow, blue or white. There are also membranes with green and gray shades in which the waterproofing effect is enhanced. The film may have reinforcing reinforcement in the form of plastic thin fibers, as well as external coatings like a layer of foil-coated aluminum. The inclusion of protective coatings is performed in order to strengthen the insulator on surfaces that are subject to mechanical stress. How to install a vapor barrier to minimize the negative effects of third-party influence? In this regard, there are many opinions related to laying techniques by one side or another. This issue will still be considered, however, it is the protective function that is best manifested in the combined installation of a vapor barrier and insulation, which is often performed in the form of relatively rigid plates.
Types of material
The film itself or the membrane can be made of different materials that differ in technical, physical and operational qualities. The following films are considered the most popular:
- Polyethylene. As a rule, a reinforced canvas with perforations, which can be used in the arrangement of ventilation shafts, where the exclusion of the "greenhouse" effect is required. Modern versions of polyethylene insulators are covered with an aluminum protective layer, although in terms of strength this is far from the best tool for a vapor barrier.
- Polypropylene More resistant to mechanical stresses, the material is also characterized by the inclusion of layers of viscose with cellulose. This makes it possible to retain moisture, preventing the passage of condensate to the insulation.
- Kraft paper based films. A special category of metal-coated vapor barriers. For example, such modifications are present in the Isospan line. The material is quite dense, and therefore requires a non-standard approach to installation. How to lay vapor barrier "Izospan" from kraft paper? Firstly, the coating is used on roofs, where it is necessary to protect the overlap of the rafter system. Secondly, the rolling is carried out on a stable platform, after which it is covered with a wooden crate. The edges are gently fixed to the supporting frame with a construction stapler.
- Non-woven diffusion membranes. A new generation of vapor isolators that “breathe” and effectively regulate the passage of water vapor. That is, two opposing tasks are balanced in a balanced way - the “greenhouse effect” is eliminated, but at the same time, sufficient throughput of the protective coating is maintained.
Preparation for work
Before starting work, it is necessary to prepare a tool with consumables, a workplace and the insulator itself. For work, you will need measuring devices, a hammer, a screwdriver, scissors, the same stapler, etc. It is important to evaluate in advance what materials you will have to deal with in specific conditions. Sometimes laying insulators affects installation structures, for example. The same is with consumables - an action plan should be outlined in advance and you will determine which fasteners are required. For example, how to lay a vapor barrier on a vertical surface? Obviously, fixing devices like wooden planks or even a full crate will be required. The only thing that is excluded is the use of metal profiles, since water vapor can lead to corrosion damage.
The following is the order of the workplace and material. The target surface is cleaned of dust, dirt and repaired if there are serious structural damage. The vapor barrier film is checked for integrity, compliance with dimensions and volume requirements.
Material Installation Instructions
Universal technology for installing a vapor barrier looks like this:
- The material is spread on the floor or pressed against a vertical surface.
- The edges are fixed with a stapler.
- If adhesive tapes are provided at the edges, then the protective coating is removed and the film is glued to the target area.
- If it is planned to install parts of the canvas, then the joints are overlapped with a grip of 5-10 cm.
- The fixed film is additionally pressed with bars or a wooden crate. But how to install vapor barrier in the floors, if installation by the type of superstructure of wooden planks is not possible? In this case, the material will have to be spread at the level of draft logs or in the niche of the floor frame. This problem is solved at the construction stage of the building frame. In extreme cases, it will be necessary to lay the insulator without the crate under the decorative flooring.
- The lath is fastened with anchors or self-tapping screws, after which it is covered with sheet wood-chip material.
Wall Mounting Features
In a wall covering, a vapor insulator most often mates with a heater. The crate system is also used in the supporting structure, but in this case, the counter crate is also integrated. First, a mineral wool slab is superimposed and fixed on the prepared frame of the bars, and then vapor barrier follows. Which side should be laid to the insulation? Installation is carried out inside to thermal insulation. There is a simple rule that the protective part turns to the room and covers the insulation. Further, the work continues according to the general technology - the material at the edges is fastened with a small hardware, and then closed with a counter-crate.
Laying roofing vapor barrier
The rear vapor barrier of skates is usually made with a glassine. At this point, the fixation points must be marked, since the installation will not be carried out according to a specially prepared crate, but to the elements of the rafter structure. Moreover, it is important to calculate the places of passage of intermediate beams between the slopes, which should be framed by a vapor barrier for the roof. How to stack the material in this case? The difficulty lies in the fact that the work will be done on an inclined surface, which is very inconvenient. Fastening is carried out by brackets, as well as on an adhesive basis. As a supplement, the material is clamped with long strips along the entire length of the laying line.
Differences in the laying of single and double layer films
Single-layer insulation is usually made of polyethylene. These are thin film coatings that need reliable mechanical protection at the installation site. Representatives of this group include the Akston vapor barrier. Which side to lay this coating? If we are talking about the non-woven membrane fabric of the “C” series, then the fastening can be done on either side. This is a universal single-layer vapor and water insulator, insensitive to external influences. Two-layer coatings have some features that affect their styling. Firstly, it is also a thick and protected material with a wide range of tasks. And secondly, from different sides functional layers can be. The purpose of each of them will determine the laying side. As a rule, one of the coatings has a mechanically resistant base with a heat reflector.
How to lay a vapor barrier on the floor?
In the floor system, insulation can be laid either under the rough flooring with the crate, or in the structure of the warm floor, and most often under the external decorative coating. In any case, the same physical effects are taken into account, therefore, the side facing up should be covered by a wear-resistant substrate. How to lay a vapor barrier on a warm floor? Prior to filling the water circuits or electric mats, a dense waterproofing system with a heat-resistant primer is laid. Further it will be possible without fixing, but evenly install a vapor barrier in combination with a heater.
Vapor barrier in a wooden house - what to consider?
Thin polypropylene membranes are optimally suited for the insulation of wooden structures. They are good because they effectively protect against condensation and other wet vapors. Since wooden houses have high thermal insulation requirements, you will have to use a combined installation scheme. Which side to install the vapor barrier to the insulation in this case? On the part of the warm rooms, three-layer polymer sheets are laid with the protected part out. Conversely, on the cold side, you can install additional superdiffusion membranes - by the same principle with external protection.
Recommendations for the progress of work
Experts recommend in the process of working activities to take into account the following nuances:
- Cloths are cut not strictly according to the size of the working area, but with slight excesses - by 1-2 cm.
- All joints must be immediately sealed either with adhesive mounting tapes, or with construction adhesive.
- If cold bridges are observed in the finished design (street air circulation), then the vapor barrier is not installed correctly and a check of joints is required. There is a greater likelihood of gaps with a structural gap.
- Combined laying with other insulators is always carried out flush.
Conclusion
When constructing critical structures, repairing or laying facing material, it will not be out of place to assess whether a vapor barrier is needed in this place. It practically does not conceal free space and is inexpensive, but its function of protecting building materials is very useful. The main thing is to perform the installation correctly. For example, how to determine which side to install the vapor barrier? First of all, you need to focus on a protective coating with a heat reflector. It should address the room. If it is not there, then you will have to identify the most sensitive side with an open membrane - it is pressed to the place of laying. In extreme cases, it is possible to perform double-sided thermal insulation, which will close the vapor barrier on both sides. The outer part can be protected with a waterproof seal.