Diffusion membranes: application, installation

In the installation of building structures, in addition to the basic properties and performance characteristics of the materials used, auxiliary elements play an important role. Among them, a special place is occupied by insulators, which ensure the integrity of the basic structure. Essential function of this component in roofing. Due to the insulating layer, a barrier is formed before precipitation and other external influences. In the market there are different means of providing such protection, but the most effective material is the waterproofing diffusion membranes, which are laid directly in the roof structure. But roofing systems are not limited to the scope of application of this coating. For example, the insulator is also used in the laying of floor and wall materials.

General information about diffusive insulators

Especially for the preservation of the technical and physical properties of the roofing, the builders use waterproofing roofing films. Most of them are realized in the form of rolls, which externally practically do not differ from each other in any way. Evaluate the same insulators can be based on different criteria, among which the vapor permeability. Actually, this is the main quality of polymer films, which causes the possibility of their structure to pass water vapor. In the language of specialists, this parameter is called the diffusion flux density. In practice, the use of vapor permeability determines the intensity of moisture passing through the roof into the rooms used. Thus, diffusion membranes minimize the possibility of penetration of sediments and their derivatives under the roof. Similar functions are performed by almost all specialized waterproofing agents, but the ability to withstand the intense effects of precipitation under conditions of gusty wind is also referred to as membranes. Also, if conventional insulation layers form only basic protection against rain drops and snow, then the diffusion film becomes an effective barrier to water vapor.

The principle of the membrane

A common problem with many waterproofing agents is the accumulation of moisture in one place - usually in front of an impenetrable layer. Proper installation provides special channels for liquid removal, but this method does not eliminate all operational problems. The diffusion membranes, which are included in the roofing "pies", work on a different principle. It acts not passively, but actively, that is, do not provide a stationary barrier, but at the expense of a special layer conducts moisture from the heater to the place of future run-off or weathering. Therefore it is very important to have the right side of the material in the work area.

The very structure of the functional fabric of such insulators resembles a capillary pump, which is formed by two layers. Fleecy fabric serves as a collector of moisture and transfers it to areas with perforations. Further along the microscopic holes, droplets with steam seep onto the outside of the web. In such a moisture drain scheme there is a risk of liquid contact with the metal elements of the roofing structure. To prevent corrosion, a volumetric diffusion membrane is used on a polypropylene non-woven basis. Also, to save moisture-sensitive materials will help films with increased throughput - they quickly provide moisture removal, reducing the chances of destructive processes.

Types of membranes

There are different types of coatings of this type by several criteria, but the main thing is the degree of vapor permeability. In particular, low- and high-permeability insulators are isolated. The first category includes diffusion membranes, which consist of 2-3 layers with reinforcing mesh. Such a material has average capacity to conduct water vapor, but as a universal protection against precipitation can be the best solution. High-permeability materials exhibit a higher level of throughput, which is why they are also called superdiffusion films. Again, the high rate of moisture holding does not allow it to condense, which helps to protect the warming layer from destruction. For this reason, builders simplify the insulation layers, relieving them of ventilation gaps.

Also, in some cases, special types of vapor-permeable films are used, among which the mentioned bulk membranes. This material is usually used to insulate the seam and metal coatings. Mount volumetric separation diffusion membranes with an upper air gap on the roofs made of aluminum, steel, titanium and other metals.

Characteristics of diffuse membranes

The main performance indicator of such materials is vapor tightness. But other characteristics are also taken into account when selecting - for example, grammature, water resistance and temperature resistance. As for the grammage, it denotes the mass of the film, which increases in proportion to the thickness of the material. Also, as the weight increases, the mechanical strength of the insulation also increases. On the market you can find films that range from 60 to 270 g / m ² . It is also important and the resistance of the coating to water pressure. This characteristic indicates the watertightness, which has a diffusion membrane in a specific design. There are different methods for estimating this parameter, but the simplest is a system that provides for marking by classes W1-W3. Thus, the membership of the membrane in the category W1 indicates that the material can withstand the water column pressure, whose height is 20 cm, for 2 hours.

In addition to precipitation and humidity, damage to waterproofing films can cause warm sunny weather. In the standard version, these materials withstand a peak temperature effect in the range of 80-100 ° C. As for resistance to ultraviolet radiation, for example, the diffusion membrane "Technonikol" in the basic version can be exposed to direct sunlight for 3 months. For enhanced modifications, this time interval increases to 4 months.

Application in roofing construction

In the composition of the roof, the insulation membrane provides protection to the insulation and internal parts of the structure. The layer performs several functions simultaneously - besides protecting moisture and steam it also protects the roof elements from weathering. It is wrong to refer the tasks of this material to the isolation of the building's premises. The main functions of the membrane still extend to the protection of the warming layer, which, in turn, regulates the humid, and in some cases also the temperature, regimes. During the design of the membrane device, it is necessary to prevent the possibility of water draining from the film surface to the heat insulator at the junctions. As a rule, the under-roof diffusion membrane is adjacent to the ventilation ducts, fireplace and chimneys, antenna racks and other third-party components, the intersections with which must be isolated.

Application of membranes in the device of floor coverings

Ensuring reliable insulation is required in the premises themselves. So, the floor surfaces retain their decorative and technical qualities only in conditions of optimal temperature and humidity regime. Of course, there are materials that are not sensitive to the same effects of moisture, but wood surfaces do not. Usually, the use of diffusion membranes in floor coverings is limited to creating an auxiliary substrate for the insulation. However, the floor on which works are performed can have a value. The most demanding is the lower level in the private house, especially if it connects the living quarters with the basement.

Application in facing of walls and facades

With the help of a diffusion film they also provide protection against weathering and moisture of thermal insulation materials that are part of ventilated facades. The membranes are placed on the outside, thus allowing the excess moisture and steam to pass through the vented gap in the lining. Installation is carried out directly on the facade of the house together with heat-insulating panels. By the way, if a metal bearing frame is used in the design, a volumetric diffusion membrane will ideally be used that will create a natural drain of moisture without the risk of corrosion. If you plan to use in the decoration of siding or lining, the film should be fixed close to the outside of the insulation under the decorative lining. This is one of the simplest ways to use diffuse insulators, since it requires minimal effort in terms of installation - it is enough to use a construction stapler or galvanized studs and fix the material to the supporting structure.

Installation of diffusion membrane

With the external method of material placement, it is desirable to perform the operation in dry weather and together with fixing the heat insulator. The membrane should be rolled out over the entire working surface and fixed with cloves or staples. Classical installation on the roof involves laying horizontal strips with an overlap of about 15 cm. At the same vertical joints of the endings should be placed on rafters. All points and lines of gaps between individual pieces of material are fixed with a butyl rubber or acrylic tape. Ventilation clearance is not required if the diffusion membranes are to be installed on the roof, but when laying the insulator on the facade surfaces it is better to provide for it. In winter, the load on the thermal insulation material is significantly increased, so it is recommended that in autumn the roof revision be checked for the density of the membrane adherence to the insulator. If the rafters have a thickness greater than that of the heat insulator, the vapor-tight material should be pressed against the side of the rails with a size of 2x3 cm. Also, for this task, you can use construction clamps. In the course of work, one should be guided by the fact that the lower edge of the membrane ensures unimpeded removal of moisture in a special drainage gutter.

Manufacturers

Non-woven vapor-proof material is represented on the market by different manufacturers, among which there are many domestic ones. In particular, the diffusion membrane "Technonikol" allows you to arrange waterproofing, which simultaneously protects the structure from contact with moisture and gives the surfaces "breathe". The material of this line is presented in several versions, including with reinforcing fibers. Also, users have gained the confidence of the superdiffusion film "Technonikol", which is made of a three-layer microporous material. The difference of this insulator is the two-side application of non-woven polypropylene, which performs a protective function for the main interlayer. Such a membrane is advisable to use it in roofing, which requires not only a high-quality performance of insulation tasks, but also the preservation of the strength properties of the structure.

A well-known manufacturer of vapor-proof waterproofing agents is DuPont, which specializes in protecting wall and roofing systems through air and water filtration. Under this brand comes the diffusion membrane Tyvek, which is a multifunctional hydrosensitive film. The material has a mesh structure formed by polymer fibers. Unlike competing insulators, Tyvek coatings are environmentally friendly. That is, they can be used both in exterior finishing and in the structure of internal facing coatings. In both cases, the inclusion of a diffusion film of this brand will ensure the dryness and durability of the finish.

Conclusion

The traditional methods of insulating layers usually do not require special installation conditions. It is enough to pick up a sheet or a plate of the appropriate size and fix the material on the working site. By this principle, it is usually mounted and a thermal insulation material, and waterproofing. The diffusion membrane, in turn, guarantees a higher operational effect than conventional insulators. But to achieve it, it is important to observe the rules for locating and fixing vapor-proof films with respect to the heat-insulating layers. Roof structures in this respect are the most difficult, since moisture-releasing material can contact other coating components and roof systems. Also, initially, communication for drainage, with which the diffusion material will interact, should be provided. From the installation point of view, installation of insulators on walls and facade structures looks a bit easier. In such cases, after all, the task of preserving the ventilation properties of the coating, which is realized due to the inclusion of a vapor-impermeable membrane in the composition of the insulation layer, is the first place.