Membrane vapor-permeable waterproofing: types, applications and reviews

After you have warmed the walls of the house, during which time inexpensive mineral wool was chosen , a problem may arise that some areas of the walls are damp. In order to avoid such negative consequences, it is necessary to use a vapor-permeable membrane.

Application Features

The process of warming the walls and arranging the roofing structures involves the use of such films that fit under the layer of mineral wool. If you are facing the task of warming from the inside, then it is necessary to provide a barrier to water evaporation. It is not recommended to use a material that has perforations or pores. The coefficient of vapor permeability for this layer should be minimal. It is preferable to use a film of polyethylene, which can be reinforced.

Aluminum foil will not be superfluous. Do not forget that when using a vapor barrier you need to think about the availability of a ventilation system. There are also special films on which anticondensate coating is applied. Such a vapor-permeable membrane can not form a condensate on its surface. The material is usually placed under layers that are susceptible to corrosion. This can include a galvanized sheet, corrugated board and metal (the latter does not have a protective inner coating).

The film will not allow wet fumes to get to the metal. To do this, there is a rough fabric layer on the back side, which is necessary to collect moisture. Lay the film with an anticondensate coating with the fabric side facing down, retreating approximately 2-6 cm from the layer of mineral wool. Those building membranes that can pass evaporation are used when the walls are insulated from the outside, they protect the materials from gusts of wind and can be laid in the structures of pitched roofs. Their use is also advisable in unsealed facades, when it is necessary to lay a protective layer against moisture. For permeability, the films have perforations and microscopic pores. The moisture that accumulates in the thermal insulation must pass through them into the ventilation system.

The main types of vapor permeable waterproofing membranes

The membrane is permeable to several types. It:

• Material of the presolidodiffusion type;
• Diffusion membrane;
• Superdiffusion membrane.

The first variety is capable of passing about 300 g of vapor per day. This indicator is relevant for every square meter. If it is a diffusion membrane, the vapor permeability coefficient can vary from 300 to 1000 g / m ² . In superdiffusion membranes, this figure exceeds 1000 g / m ² . For the reason that the pre-diffusion membranes are protected from moisture, they can be used under the roof as an outer layer. It is necessary to provide an air gap between the thermal insulation and the film.

With facade insulation, such materials can not be used, because they do not pass steam well. After all, when it's dry enough on the street, dust can get into the pores from the ventilation. This will cause the film to cease to "breathe", and the condensate will settle on the layer of insulation.

Reviews about the vapor-permeable membrane

Membrane vapor permeable must be stacked by special technology. If we are talking about a diffusion or superdiffusion membrane, then the pores are large enough, so they will clog up pretty soon. This makes it necessary to have an air gap for ventilation from the lower side. According to users, while not having to mess around with the installation of the lath and counter-rake. On sale it is possible to meet not only diffusion films, but also their volumetric variety. As the buyers emphasize, the interlayer for ventilation is located inside them. Due to this, the condensate is unable to penetrate into the roof of the metal. The principle of operation of such a material is the same as that of an anticondensate film. However, there are differences. As the domestic craftsmen emphasize, the volumetric membrane is able to remove moisture from the heater. After all, if the metal roof has a slight slope in the range of 3 to 15 °, then the condensate from the lower side can not flow down. He will undermine the galvanized coating and gradually completely destroy it.

How to install the membrane - on the inside or outside of the heater?

The vapor-permeable waterproofing membrane must necessarily be laid down by a certain technique. If it is necessary to heat-insulate the facade, then the vapor discharge film must be located on the outside. Whereas if it is necessary to insulate the roof, then a film with an anticondensate coating of bulk or diffusion type is laid on top of mineral wool. In this case, it is necessary to follow the technology, which is used in the arrangement of ventilated facades. If the roof does not have a heater, then the film layer should be at the bottom, under the rafters. With thermal insulation of the upper ceiling of rooms under the attic, the vapor-permeable membrane must be laid from the bottom of the heater. A vapor-permeable waterproofing membrane should also be used for internal insulation of walls. In this case, it should not have perforation, and lay it on top of the mineral wool, inside the room.

How to lay the membrane - the wrong side or face?

As practice shows, for many people it remains a mystery which side to lay the vapor-permeable membrane. If the film has the same back and front, then the question is immediately removed. However, it is not always possible to find two-sided films on sale. If we are talking about an anti-condensate variety, then there will be a fabric side from the inside, and at the installation it should be turned into the interior of the room. It is also necessary to turn the metal coating on the foil membrane.

If a diffusion membrane has been purchased vapor permeable, then you should familiarize yourself with the instructions. In it, the manufacturer usually indicates the technology of laying the material. However, one and the same company can produce single-sided and double-sided films. Determine the outer and inner sides can be by color. If the membrane has two sides, then one of them is painted in a brighter shade, usually the outer side of the material.

How to choose a membrane

If you need a wind-moisture-proof vapor permeable membrane, then you can pay attention to the most often purchased by buyers option "Izospan A", which is designed for laying in the under-roof space. It is used to protect against condensation and wind elements of walls and roof during the construction of the building. The membrane should be located under the roofing or wall lining on the outside of the thermal insulation. The outer side is a water repellent smooth surface, while the inner side has a rough anticondensate structure. It is intended to delay moisture and subsequent evaporation in the air stream. This windproof vapor permeable membrane is easy to use, it is characterized by high mechanical strength and environmental safety. In evaporation there are no harmful substances, and the properties of the material can be preserved for a long time. The material is resistant to bacteria and chemicals.

Features of stacking material "Izospan A"

The vapor-vapor-permeable membrane "Izospan A" is used as a windproof membrane for the arrangement of heat-insulated roofs, the angle of which must not be less than 35 °. As an external coating, profiled sheets or bituminous shingles can be made.

Features of the membrane "Megaflex"

Do you need a vapor permeable membrane? Which is better, you need to decide before you go shopping. One of the types of such materials is "Megaflex", which is a three-layer structure. Two outer layers are microperforated, and the inner layer is a reinforced film. Reinforcing mesh gives strength to the material, while double-sided lamination provides waterproofing properties.

The material has micro perforation, which guarantees the ventilation of water vapor coming from the interior. This moisture-proof vapor permeable membrane is able to protect the under-roof space from humidity, dust and soot, to protect the materials from external moisture and internal condensate. If wind protection is required, then a version of "Megaflex D 110 Standard" should be used, which is rolled out with horizontal overlaps with an overlap of 15 cm.

Conclusion

A hydro-windproof vapor permeable membrane that protects materials from moisture, wind and fumes should be present in insulated roofs and ventilated facades. In the first case, the gap is arranged by the method of constructing a counter-grate, whereas when the facade is insulated, a gap can be obtained when mounting horizontal profiles or racks.