Vapor barrier for pitched roofs. Vapor barrier film for roofing. Optional accessories: adhesive tapes and adhesive tapes
TechnoNIKOL is a leading manufacturer of roofing, steam and waterproofing materials in Russia and the CIS. Factories producing polymer-based vapor barrier are located in Russia, Belarus, Lithuania, Ukraine and the Czech Republic. TechnoNIKOL vapor barrier meets European requirements, quality and safety standards, which allows it to be successfully used for low-rise residential and industrial construction of houses with various insulation systems.
Vapor barrier materials are designed to protect the insulation from condensate that forms inside the room. The installation of a roof and wall insulation system is not allowed without the use of vapor barrier in accordance with SNiP 23-01. The vapor barrier of the roof prevents the formation of condensate on the materials that make up the roofing “pie”, ensuring the preservation of the optimal microclimate in the house for a long time. The use of a vapor barrier prevents the appearance of mold, fungus, and unpleasant odors.
The vapor barrier layer is laid immediately before the installation of the thermal insulation material. The choice of vapor barrier material depends on the temperature and humidity conditions in the room, the climate of the region, financial possibilities, the material of the roof, walls. TechnoNIKOL vapor barrier film is made of high-quality polymers and has a multilayer structure, due to which optimal vapor permeability and high strength are achieved.
Important! Before laying the foil, carefully study the "Installation and Design Guide for Roofing" issued by the manufacturer. Strictly follow the instructions and do not use the material for other purposes.
The TechnoNIKOL company produces several types of vapor barrier:
- for pitched roofs, with the ability to partially pass steam;
- for flat roofs, having high strength, elasticity;
- reinforced, reinforced three-layer film of high strength;
- universal, applicable to all types of roofs.
Physical and mechanical characteristics of TechnoNIKOL vapor barrier films
Vapor barrier OPTIMA
The peculiarity of this material is excellent vapor permeability and at the same time a high rate of vapor barrier. This is possible thanks to a three-layer membrane in which the top and bottom layers are made of non-woven polypropylene, and the middle layer is a vapor-permeable film. The combination of OPTIMA material with fibrous insulation provides the temperature and humidity in the room as close as possible to a log house, creating comfortable conditions for year-round living.
Technical characteristics of OPTIMA vapor barrier:
- tensile load along the length and width - 160 and 120 N / 5 cm;
- vapor permeability - 5 Gy / (m / day);
- thickness - 0.3;
- water resistance - > 2 m of water. pillar;
- operation at temperatures from -40 to +85 degrees;
- high resistance to UV rays.
OPTIMA is a universal material and is used for the installation of a vapor barrier layer in insulated attics, sloped roofs without insulation, ceilings, external walls with a multilayer structure (ventilated facade), as well as for walls with internal insulation of any type. Steam penetrates through the bottom layer, lingers in the vapor-permeable layer. Part of the steam passes through the top layer and the insulation into the environment, providing the "breathing" properties of the roof. The material is easy to use, produced in rolls 1.5 m wide. OPTIMA is a TechnoNIKOL film, the vapor barrier and strength characteristics of which allow it to be used as a wind protection in areas with an unstable climate.
Vapor barrier for pitched roof
Vapor barrier for flat roofs
Vapor barrier TechnoNIKOL for a flat roof is a three-layer polymeric material, all layers of which are made of polyethylene. The film has a double effect:
- Protects the roof from the penetration of water from the outside, i.e. from precipitation.
- Provides protection for flat roof elements from steam generated indoors.
TechnoNIKOL is laid on concrete surfaces under insulation or on a profiled sheet, mounted before laying thermal insulation. Compared to OPTIMA, this material has higher tensile strength and higher vapor permeability at a smaller thickness.
Important! The use of vapor barriers for flat roofs that are not intended for this purpose will not provide the required protection against atmospheric precipitation and will lead to the destruction of the roof structure.
Technical characteristics of TechnoNIKOL vapor barrier for a flat roof:
- tensile load along the length and width 160 and 170 N/5 cm;
- thickness - 0.12;
- water resistance -> 1 m of water. pillar;
- medium UV resistance.
A three-layer membrane for flat roofs can be used in private low-rise construction, in the construction of high-rise buildings, buildings from quickly erected structures.
The TechnoNIKOL reinforced vapor barrier film, whose technical characteristics are significantly superior to conventional films for pitched and flat roofs, consists of three layers. The main layer is a reinforcing mesh made of durable polyethylene strips. This reinforced layer is covered on both sides with laminated polyethylene. Reinforcement provides the material with increased stability, and lamination - high vapor permeability.
Durable reinforced vapor barrier
Specifications:
- tensile strength along the length and width 250 and 160 N/5 cm;
- vapor permeability - 1.1 Gy / (m / day);
- use at temperatures from -40 to +70 degrees
The material is produced in the form of dense rolls 1.5x50 m. Reinforced film is strong, durable, not subject to mold, decay, corrosion. It is intended for the installation of a vapor barrier layer for attics, mansards, sloping and flat roofs. Due to its high strength and heat-resistant characteristics, the membrane can be used in the external insulation system. Reinforcing mesh made of polyethylene helps to retain heat, acting as an additional heat insulator, and layers of polyethylene retain condensate, preventing it from penetrating into the insulation.
Important! When calculating the load on the roof, it must be taken into account that the specific gravity of the reinforced film significantly exceeds the weight of conventional three-layer ones. In some cases, to reduce the load on the roof, reinforced vapor barrier should be abandoned.
Reinforced film can be used with all types of insulation: fibrous, foam and polystyrene foam. The manufacturer recommends combining it with a heater of its own production based on polystyrene, produced under the Technoplex trademark.
A type of reinforced vapor barrier is the Svitap 110 D windproof film, designed to protect surfaces from dust and moisture. This material is used in industrial construction and for the construction of low- and multi-storey buildings in special climatic zones. Windproof reinforced vapor barrier can only be used for ventilated flat, pitched roofs or as a waterproofing material for ventilated facades.
Reinforced vapor barrier for pitched roofs
Advantages and disadvantages of materials
The advantages include:
- high tensile and tensile strength;
- not subject to rotting, prevents the formation of mold, fungus;
- high rates of vapor permeability and water resistance;
- fire safety, the film does not support combustion;
- the ability to use in the Russian climate;
- compliance with the norms of the Russian Federation and the Customs Union;
- affordable prices.
The disadvantage of TechnoNIKOL polymer insulation is considered to be low resistance to sunlight in most types of films. The rolled material should be covered as soon as possible with the next layer of roofing or insulating “pie” in order to minimize exposure to UV rays.
The affordable cost of TechnoNIKOL is the reason for its popularity among private developers and construction companies. Prices for different types of film from the manufacturer are presented in the table below. Depending on the region and the specific supplier, prices may vary.
Installation of TechnoNIKOL vapor barrier
Vapor barrier can be installed in three versions:
- When installing internal insulation of walls or roofs, on the inside of the insulation under the finishing of the room.
- As a vapor barrier in uninsulated attics.
- When installing an external wall insulation system, residential attics, ceilings.
In each case, the installation will have its own characteristics, which we will discuss in more detail.
Vapor barrier in the internal insulation system
In this case, TechnoNIKOL is located on the inside of the insulation in the form of vertical or horizontal stripes. Fastening is carried out directly to the insulation or to the wooden slatted frame using a construction stapler with medium-sized staples, as well as using dowel-nails made of galvanized sheet with a wide “mushroom” hat. Strips of material are hermetically glued together with a mounting tape.
The extreme strips must be brought 20-30 cm beyond the insulated surface and carefully sealed. Wooden or metal slats are installed on top if the room will be finished with siding, drywall, cork panels.
Important! Between the interior finish and the vapor barrier layer, a ventilation gap of at least 3 cm must be provided.
All joints must be sealed, otherwise the vapor barrier will not perform its function: condensate will penetrate into the insulation layer, it will lose its thermal insulation properties and the walls will become damp.
Vapor barrier in non-insulated roofs
The TechnoNIKOL vapor barrier film is rolled out on the rafters and fastened with dowel-nails or building brackets. The strips of material are overlapped, starting from the eaves to the roof ridge. The overlap of the strips horizontally should be at least 15 cm, and vertically - 20 cm, while the vertical joints should be located on the rafters.
Important! The formation of joints, creases, sagging on the film is unacceptable. this contributes to the accumulation of moisture.
Accumulated moisture must be removed along the lower edges of the film into the drainage gutters. A frame of wooden slats is laid on top of the vapor barrier layer, and then the final finish.
Vapor barrier in the external insulation system
Reinforced vapor barrier TechnoNIKOL, the technical characteristics of which allow it to be used in external insulation, can be mounted horizontally or vertically on top of the heat-insulating material. Fastening is carried out with staples or dowel-nails. Reinforced film can be fixed on either side. Joints must be securely sealed with adhesive tape or mounting tape. Joints adjacent to the structure must be additionally sealed with foam or outdoor sealant.
When installing a ventilated facade and other types of insulation using TechnoNIKOL films, it is necessary to constantly monitor the integrity of the material, preventing it from breaking.
External insulation using TechnoNIKOL
Video: production of TechnoNIKOL vapor barrier films
TechnoNIKOL is a modern material that meets all the requirements for vapor barrier in combination with various heaters. High quality and affordable price have made the products of TM TechnoNIKOL one of the most popular in the market of the CU countries. When choosing this vapor barrier, be sure to pay attention to the characteristics of the insulated surface and buy the material that best suits its type: a pitched or flat roof, a wall or an insulated attic.
Purpose and location of the vapor barrier
It is known that the roofing cake consists of several layers (that's why it is called so). It may include a different number of layers, but hydro, heat and vapor barriers remain unchanged. And if the waterproofing is designed to prevent moisture from penetrating inside the house from above, then the vapor barrier does not allow evaporation from the inside to enter the roofing pie.
It is extremely important to place the vapor barrier below the thermal insulation material, otherwise it will absorb steam coming from below, swell and become damp. However, we all know that there are non-insulated roofs, can they really be made without vapor barrier? Unfortunately, no - the vapor barrier not only preserves the insulation, but also maintains a comfortable indoor climate. If it is not there, the house will be very stuffy and humid, and cozy housing will turn into an ordinary greenhouse.
In order to fully appreciate and understand the roof vapor barrier device, you should study the structure of the roofing pie:
- Roof covering can be continuous or consist of segments (tile, slate). It is laid on a wooden crate or a monolithic base.
- Waterproofing layer - protects subsequent layers from the penetration of moisture from the outside. It is a waterproof non-woven material that is attached to the crate, leaving a small gap between the next layer.
- Insulation - roofing heat-insulating materials are plates with minimal thermal conductivity. They can be made from pressed mineral or rock wool, styrofoam or polyurethane foam. Depending on the material, water absorption is also different, which also affects the choice of vapor barrier. Polyurethane foam and polystyrene are practically not afraid of moisture, but mineral and stone wool require the installation of high-quality vapor barrier.
- Vapor barrier layer - films or membranes are installed on the crate immediately after the insulation and leave a gap between the sheathing ceiling material to ensure natural ventilation. When the water vapor coming from below hits the membrane, condensate will form, which will flow down and dry out due to the ventilation of the under-roof part.
Even the highest quality and most modern vapor barrier will not “work” if you do not take care of roof ventilation. Ventilation is important at any time of the year - in winter it will help to keep warm and prevent ice on the roof, and in summer it will give more coolness.
If a vapor barrier is missing or incorrectly installed in the roof of the house, this will inevitably lead to the formation of non-weathered condensate, dampness, mold and fungi. Eventually the wood structures and roof elements will rot and collapse.
Vapor barrier materials
Today in the construction market you can find a lot of roofing materials. Most of these are films based on polyethylene. They are waterproofing, vapor barrier and antioxidant. The latter are special in that they are covered on the inside with an absorbent fleecy fabric layer that actively collects condensate, preventing it from getting onto the next layer of the roofing pie.
Previously, parchment was the main material for roof vapor barrier. Today, only overly economical builders use it, but if you look at the performance characteristics of glassine and compare them with the qualities of modern materials, then the benefits of the latter will be obvious.
Depending on the physical and technical parameters, three types of vapor barrier films can be distinguished:
All film materials used for vapor barrier must have good elasticity, be tear-resistant and be as comfortable to use as possible. It is extremely important that the vapor barrier film does not tear during fixing, but wraps around the fastener. Even in case of accidental mechanical damage to the roof, for example, due to a tree branch that fell during a hurricane, the vapor barrier must maintain integrity, minimizing losses. Ideally, the thickness of the roof vapor barrier should be such that the material can withstand the load of thermal and waterproofing if the battens and rafters fail.
Vapor barrier isospan
One of the most popular materials in the domestic market is isospan roof vapor barrier. It is relatively inexpensive, has impeccable performance, durability and ease of installation. Izospan can be used for waterproofing and as a vapor barrier at the same time.
The manufacturer offers several different modifications of Izospan, each of which is designed for a specific purpose, but there are also universal films. Therefore, it is very important to clarify the characteristics of the selected material before purchasing, so as not to accidentally buy the wrong variation of Izospan.
Izospan V is widely used among professional builders and self-taught owners. It can be combined with any type of roofing. In addition to protecting the insulation from moisture, it does not allow the microfibers from the cake to crumble into the room, as is often the case with other materials.
Vapor barrier installation
It does not matter whether you are making a vapor barrier for a flat roof or working with a gable roof - the film or membrane should be installed only after the insulation has been laid.
Features of installation of vapor barrier:
- Cloths can be installed both vertically and horizontally.
- If you prefer horizontal installation, start installation from above.
- Lay the pieces of cloth with an overlap of at least 10 cm. Be sure to glue the seams with single-sided or double-sided adhesive tape.
- Choose a wide ribbon of at least 10 cm.
- Double-sided tape is glued inside the overlap - first stick it on the bottom layer, then remove the protective coating and fix the top one with an overlap.
- If you are laying a vapor barrier along the rafters without a rough filing of insulation, overlap and fix the sheets directly on the rafters.
- The vapor barrier is attached to a wooden crate or rafters with a construction stapler or galvanized nails (they do not rust).
- It is recommended to strengthen the places where the sheets are glued with clamping strips. This advice is especially relevant for roofs with a slope of up to 30 degrees and with loose thermal insulation.
- At the junction points to the aisles, hatches or dormer windows, a so-called dormer apron should be organized through the roof, which is usually included in their package. If it is not available, glue 2-sided butyl tape around the perimeter of the window frame or opening.
- In places where water pipes pass through the roof, wrap the vapor barrier material down, wrap it around the pipe and seal it tightly with electrical tape.
When the vapor barrier is laid, attach antiseptic-treated bars on top of it at a distance of 50 cm from each other. Thus, you will create an air corridor where condensate will quickly evaporate, and the film will not touch the ceiling sheathing. If you are using a vapor barrier membrane, the bars are optional. But they will come in handy to occupy this space with various communications. If you are planning to finish the interior of the house with drywall, use a galvanized metal profile instead of wooden bars.
Errors when installing vapor barrier
Very often, when arranging a roofing pie, builders make mistakes that lead to fatal consequences. If you confuse the location of the insulating layers, the roof may become unusable after a year of operation.
We have prepared a list of the most common mistakes when installing a vapor barrier:
- The joints of the film are not hermetically sealed, as a result of which the effectiveness of the vapor barrier is reduced to a minimum, the insulation becomes damp, and the truss structures begin to rot.
- Using a narrow adhesive tape to seal the seams - during operation, adhesive tape 5 cm wide or less will simply peel off. The recommended tape width is 10 cm or more.
- There is no deformation margin when working with window openings - any house shrinks, so it is required to leave a margin in the form of a fold of 20-30 mm.
- The film around the roof windows is not protected by the interior decoration - if this is not done, after a few months of operation, the vapor barrier will completely become unusable and collapse under the influence of sunlight.
- The film wraps around the rafters - if the vapor barrier material goes around the rafter legs, moisture will penetrate to the wooden elements, as a result of which they will begin to rot.
- Where the vapor barrier is adjacent to the internal walls of the house, shafts or chimney, it is necessary to take into account the specifics of the irregularities to which the material will be attached in order to ensure the tightness of the fixation.
- If you are attaching the film to a rough brick wall or rough wood surface, you can only do this with polyurethane, acrylic adhesive or synthetic rubber.
- Do not use polyurethane adhesive tapes and butyl rubber tapes, as they do not adhere well and may soon peel off the surface.
The penetrating power of water vapor is extremely high, so you should approach the vapor barrier device very responsibly. In addition to the popular Izospan, TechnoNIKOL roof vapor barrier is widely used today. The most important thing is to correctly select the materials and install them in the right sequence, then the roofing pie will last for decades without repair.
Vapor barrier
VAPOR INSULATION OF THE ROOF. VAPOR PROOFING OF WALLS.
Modern, energy-efficient residential buildings are built using contemporarythermal insulation materials. With their help, not only the outer walls are insulated, but also the ceilings and the roof. However, for durable and reliable thermal insulation of the cottage, it is important to pay attention not only to the choice of high-quality insulation, but also to the vapor barrier device.
In a heated room, moist steam is formed, the pressure of which is much higher than atmospheric pressure. Steam puts pressure on all building envelopes - walls, ceilings, roofs, trying to get out. Modern thermal insulation materials based on mineral fiber have good vapor permeability, i.e. "breathe". However, in winter, at sub-zero temperatures, moisture vapor inevitably “gets stuck” in the heat-insulating material: having reached the dew point (the section of the wall where conditions arise for the transformation of steam into water), the steam will not be able to move on and will begin to condense. The result - the insulation, and sometimes the wall itself, will get wet. To avoid this, another layer is added to the structure - a vapor barrier.
1. Vapor barrier
2. Frame
3. Roof
The purpose of using a vapor barrier is to prevent the ingress and accumulation of moisture in the insulation. Vapor barriers are widely used in the construction of pitched and flat roofs, frame-type walls. In other words, the vapor barrier creates a vapor barrier on the inside of the insulation to keep the insulation dry for the entire service life.
The ability of vapor barrier materials to prevent steam from entering the thermal insulation from inside the room reduces the likelihood of an increase in the thermal conductivity of the insulation due to possible condensation of water in it. The installation of a vapor barrier layer is a very important stage in the production of work, especially in the case of frequent temperature changes. If the vapor barrier is poorly installed, then the thermal insulation and the frame of the roof and wall quickly lose their functional characteristics, the house becomes damp, mold and fungus start up. The vapor barrier layer must be airtight. The joints of the canvases are glued together, and the junctions are glued with sealing paste.
HEAT-REFLECTING VAPOR INSULATION
Recently it has become widespreadvapor barrier membranes, which also partially perform the functions of thermal insulation, with a special heat-reflecting layer. The vapor barrier metallized material is made on the basis of kraft paper with aluminum foil applied. This material seems to be very effective in isolating baths and saunas. Its use allows, on the one hand, to prevent the penetration of water vapor into the wall structure, and on the other hand, thanks to the aluminum coating with a reflectivity of more than 95%, significantly reduce heat loss through the walls.
FLAT ROOF VARIATION
Vapor barrier in flat roofs plays an extremely important role. The vapor barrier layer is a barrier to the penetration of moisture vapor from the warm space below into the thickness of the insulation. As a result, the thermal insulation remains dry, retaining all the declared thermal insulation properties. As a vapor barrier membrane in flat roofs, as a rule, a polyethylene film with a density of at least 180 g / m2 and a thickness of at least 200 μm is used. Particular attention should be paid to the resistance of the film to ultraviolet radiation - ordinary polyethylene quickly loses its strength properties under the influence of sunlight, and it is not always possible to quickly close the vapor barrier film with insulation.
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Vapor barrier performs one of the most important functions in the preservation of the entire roofing. If there is no vapor barrier in the roof, the under-roof layers are quickly saturated with vapor from the interior, which completely destroys them over time. In addition, such a structure begins to freeze in winter, thaw in spring, and mold, fungus and similar problems appear in it.
But modern technologies for the construction of residential buildings cannot be imagined without close attention to efficient energy saving. Therefore, insulating materials are selected especially carefully and thoughtfully, which are presented on the market in a huge number, of various types and functional purposes. And TechnoNIKOL acted quite wisely in this regard, having developed only a few solutions, but each of which is universal for its task.
The domestic company TechnoNIKOL is rightfully considered one of the largest international manufacturers of building materials. This company has its own research centers, actively studying world experience and developing new technologies. In total, TechnoNIKOL has its production sites in 7 countries of the world and provides its products to more than 80 countries.
Specifically for the roof, it produces roll coatings, drainage and polymer membranes, thermal insulation, sealants, soft tiles, and even materials for transport and road construction (not only inverted roofs):
Let's take a closer look at each of these solutions.
Vapor barrier for pitched roofs: a thoughtful barrier
Such a vapor barrier for TechnoNIKOL roofing, popular in Russia, is presented in three versions:
Vapor barrier films
The standard TechnoNIKOL vapor barrier film has a three-layer structure. Its strength and reliability are provided by both outer layers, which are non-woven propylene sheets. Both serve as a frame for the middle layer, a polypropylene film with a special vapor control function. And all these layers are connected in the factory using the technology of low-temperature ultrasonic welding.
In addition to standard vapor barrier films, TechnoNIKOL has one type of vapor barrier - reinforced. It is based on a mesh of polyethylene fiber and strips, which are laminated on both sides with a film. Such a mesh gives strength to the material, and double-sided lamination - the necessary vapor permeability. And for the manufacture of such products, serious equipment is involved:
Super diffuse membranes
By the way, today it has become quite fashionable to produce materials for construction and repair, which are inherently universal. These combine several functions at once and greatly facilitate all the work. This is what TechnoNIKOL vapor barrier is good for: the technical characteristics of its membranes differ significantly from each other.
So what is a membrane? This is a single or double layer PVC sheet with an embedded mesh that serves as reinforcement. Such a web has good tensile strength and minimal risk of deformation due to temperature. But be prepared for the fact that all the same, some percentage of moisture through subtle damage to the membrane, poorly sealed joints, or the material itself simply cannot withstand all 100% of the steam. But, if you correctly left a gap above the insulation on the other side of the roof, such a small amount of moisture can easily be removed from it.
Such multilayer vapor barrier protective films and membranes from TechnoNIKOL allow you to save not only heat, but also a healthy microclimate in the living room. And he, in turn, will take care of the health of the household and the durability of the furniture with appliances inside the room.
In addition to the insulated roof, TechnoNIKOL super diffuse membranes are also used to protect cold roofs:
Separately, we note a special type of superdiffuse membranes from TechnoNIKOL - this is Optima. It is a microporous three-layer membrane, especially durable. It provides diffusion of water vapor, but does not allow water to pass into the roofing cake. Its special modification is a reinforced membrane.
foil vapor barrier
TechnoNIKOL also has such a fashionable and unusual vapor barrier as reflective. We are talking about the membrane "Varobarrier". In fact, this is the first domestic material of this type. Compared to foreign counterparts, it is also affordable. Such a membrane has high breaking characteristics, it even withstands the weight of a person and remains intact after the fall of improvised tools. Needless to say, in terms of its properties, it is much better than conventional vapor barrier films.
The Vapor Barrier membrane is self-adhesive, and therefore it is easy to work with it. Such a vapor barrier is also intended for installation in roof structures, in which there is a load-bearing base made of galvanized profiled sheet. At the same time, its self-adhesive backing is recognized as a serious advantage during installation. After all, such material not only quickly fits, it is also not affected by strong gusts of wind. The maintainability of the membrane was also noted. Workers can easily move on such a roof, right on the membrane, and it can even serve as a temporary roof during a break in work.
And the "Varobarrier" is produced in the following two versions:
- Vapor barrier "SF 500" - for reliable protection against steam. Also, "Varobarrier" 500 passes 4 times less steam than a conventional vapor barrier, but the material of the "SF 1000" vapor barrier is rightfully considered almost 100% impermeable.
- Vapor barrier "SF 1000" - for especially wet rooms. The steam barrier brand "SF 1000" is intended for rooms with a special high humidity, these are pools, saunas, baths, and with a500 absolutely for all types of buildings with normal humidity. The bursting characteristics of the vapor barrier are estimated at 600 m 500 n. Such a vapor barrier can be used in a building with absolutely any fire safety class.
The TechnoNIKOL company has recently been producing a special foil insulation for baths, where the heat-insulating layer itself is covered on both sides with aluminum foil, which simultaneously serves as a reliable vapor barrier! Such plates are inserted into the crate, clamped with slats and facing material, and no additional fastening with films or membranes is needed. At the same time, the insulation turns out to be environmentally friendly, without dust or fumes that are harmful to health, and everything has the highest vapor barrier of all offered markets. And the plates are also light, thin, well matched to the standard distance between the rafters.
What to choose for the vapor barrier of a pitched roof?
Let's explain in more detail when a TechnoNIKOL film is needed in a roofing pie, and when a superdiffuse membrane is needed.
You probably know that all heat-saving materials are divided into types according to the nature of their pores, which are closed and open. The difference is that in closed pores the air does not communicate with atmospheric air, but in open ones it does.
Therefore, if materials with open pores are used as thermal insulation, then it is enough to use a windproof coating - vapor-permeable membranes - to prevent the effects of wind. We are talking about special perforated film membranes that allow water vapor to pass through on one side and retain water on the other. And even if you use a rather weak vapor barrier on an open-pore insulation, but on the other side of the insulation there is a vapor-permeable membrane, then such a design can also be considered competent and reliable.
It is only important, guided by modern SNIPs, to organize natural ventilation using holes in the ridge. In this design, meeting with a vapor barrier, water vapor remains in a significant amount on the other side, and what nevertheless leaked out easily passes through the insulation, vapor-permeable membrane and is carried out into the atmosphere by air flow.
Vapor barrier for flat roofs
For the vapor barrier of flat and inverted roofs, TechnoNIKOL offers its own special products - the built-up material "Bipol". It is obtained by double-sided application of a bitumen-polymer binder filler on a polyester or fiberglass base, after which it is all protected on both sides with protective layers: coarse-grained, fine-grained dressing and polymer film.
Here are the solutions in which such vapor barrier is implemented:
The Bipol vapor barrier not only protects the roofing pie from steam, but is also resistant to possible mechanical damage, which often occurs even during installation:
Optional accessories: adhesive tapes and adhesive tapes
To connect films, TechnoNIKOL produces two types of adhesive tapes - butyl rubber and acrylic. Acrylic tape - double-sided, specially designed by TechnoNIKOL for vapor barrier films and membranes. It is made of polyester mesh and coated on both sides with a special adhesive based on acrylic dispersion. Thanks to all this, such a tape is resistant to tearing and has a high bonding strength.
In addition, both acrylic and butyl rubber tapes comply with EU safety and environmental standards, which is already important:
Features of installation of TechnoNIKOL vapor barrier
If you yourself undertake the installation of a vapor barrier from this manufacturer, then pay attention to this moment: about 12-20 cm from the edge of the canvas there is a gray strip that indicates the vapor-permeable border of the film. Photos 6 and 7:
Such a vapor barrier can be mounted both horizontally and vertically, on the inner side of the thermal insulation. If you attach the canvas:
- to wooden elements, then use staples from a mechanical stapler or galvanized nails with a flat wide head;
- to other surfaces such as plastic, glass or metal, then use a double-sided adhesive tape from the same manufacturer. And after fixing the film, be sure to close all the holes with a connecting tape as well.
Due to the strength of the films and membranes of this manufacturer, all installation work is easy, accurate and does not cause any difficulties.
The main purpose of the vapor barrier layer is to protect against the ingress of water vapor rising from the room into the roof structure. The vapor barrier of a flat roof has its own characteristics: a slight slope of such a roof makes the use of upper waterproofing vapor-permeable layers undesirable.
The need for vapor barrier
Water vapor constantly circulates in indoor living spaces. The warm air saturated with them rises in the direction of the roofing cake and gradually accumulates under the ceilings. After that, diffusion occurs, during which water molecules penetrate through the leaky ceiling into the inner layers of the insulation, gradually filling the pores and accumulating there. Having reached the waterproofing layer located under the roofing, the moisture undergoes condensation, and when the temperature drops, it forms an ice crust, completely freezing the insulation material. As the temperature rises, the ice crust melts, and the resulting moisture completely flushes out the internal filling of the roof structure. The insulation layer becomes completely unusable or significantly loses its heat-insulating qualities.
So, with an increase in the percentage of moisture content of the insulation material by 1%, the thermal conductivity increases by 32%; in the case of 5% moisture, there is an almost twofold loss of heat-insulating qualities.
It is necessary to protect against the effects of steam those surfaces that serve to separate warm and cold zones. These are those areas that are in the area of active contact with warm and cold air inside the building.
Increased moisture inside the roofing pie also leads to rotting of the wooden parts of the structure, the formation of fungus, mold, and corrosion of metal guides.
To prevent steam from entering the heat-insulating layer, the accumulation of moisture in the insulation material and building structures, to accelerate and facilitate the release of excess steam, a vapor barrier or vapor barrier is used.
The vapor barrier is a special material and film, the purpose of which is to protect the heat-insulating layer and the roof structure from the ingress of steam and the subsequent formation of condensate.
Differences between hydro and vapor barrier
A common mistake of inexperienced builders who independently carry out installation work is to use the same type of material for the construction of these two different systems. Externally, the rolls are identical, in addition, both materials do not allow moisture to pass through.
The fundamental difference between these films is the ability to pass heat and vapor-saturated air. Some even tend to believe that there is a certain type of highly permeable roof vapor barrier that can be successfully used for waterproofing. The error lies in the fact that a material with high vapor permeability can no longer be a vapor barrier.
The waterproofing layer retains the water coming from the side of the roof covering, while at the same time making it possible for the air saturated with water vapor to escape from the insulation layer. It is the waterproofing that must have increased permeability.
In the case when the coating does not have such a quality, moisture begins to accumulate in the insulating layer, which over time leads to the loss of quality characteristics of the material.
Vapor-permeable waterproofing roofing film is one of the main parts of a warm roof.
The function of the vapor barrier is to protect the insulation from moisture rising from the interior. The effectiveness of a vapor barrier material increases as its vapor permeability decreases. The newest high-quality films pass only a few grams of steam per 1 sq. surface meter.
Important points when choosing a vapor barrier
The choice of vapor barrier for a flat structure must be carried out by the designer. This takes into account the following points:
- temperature zone of the building location;
- construction of a roofing pie;
- type of roof operation.
In the case of a new roofing on an insufficiently dried base or directly on top of the old coating, the base does not qualify as a vapor barrier. A steel profile cannot serve as a vapor barrier either. Despite its integrity, moisture is able to penetrate through the cracks in the areas of fasteners and joints.
Requirements for vapor barrier of flat structures and rules for its construction
- The main requirement for a vapor barrier system is absolute tightness. The material used for this purpose must be firmly stitched or welded.
- In modern construction, the roofing base is increasingly being created on the basis of steel profiled sheets to increase the level of fire safety at home. In order to achieve the greatest resistance of the roof to fire, vapor barrier (in particular, bituminous) materials are located between the insulation layer and the profiled sheet.
- For the vapor barrier device, materials with a degree of incombustibility G2 should be used. To create the bottom layer, you can use completely non-combustible materials. In this case, the vapor barrier layer should pass in the middle, between the heaters. It can be arranged on the basis of bitumen-polymer materials. To increase fire resistance, only mechanical fastening of the insulation layer should be used.
In areas of contact between the roof and the wall, the vapor barrier is wrapped onto the wall so that it extends beyond the boundaries of the insulation. The vapor barrier material is glued to the wall and clamped from above with galvanized rails. This is done to improve the reliability of fastening. In all areas of the connection, the vapor barrier must adhere firmly to all protrusions, irregularities, and components of the flat roof structure.
Composition of vapor barrier coatings
Until recently, vapor barrier, as well as waterproofing a flat roof, was carried out exclusively with the help of roofing material and glassine. Some builders and homeowners are still using these materials to save money. However, such savings are costly: in just a few years, there may be a need for repairs.
In principle, roofing material vapor barrier can be used, but when constructing roofs of structures that do not need a high level of reliability: utility buildings, garages, etc. It is recommended to use it not as the main, but as an auxiliary material. In many cases, roofing material is quite suitable for flat roofing.
Vapor barrier membranes and films
Today, a fairly wide selection of modern materials for vapor barrier is provided for the roof device. These include new vapor barrier membranes and films.
Polymeric membranes of the latest generation are a multilayer material that is characterized by increased strength and excellent performance. Vapor barrier materials based on polypropylene or polyethylene are almost always reinforced.
When installing membranes, builders use a fairly advanced technology for connecting seams to each other using a stream of hot air. The advantages of this method are speed, increased safety, excellent results.
For vapor barriers on concrete-based flat roofs, bituminous membranes are an excellent choice. They are welded onto a concrete base. The material is flexible and is able to independently recover in areas of fracture or deflection. With its use, even fastening areas become impervious due to the fact that the bitumen completely envelops them.
They are not subject to damage due to unevenness of the concrete base. High quality material is offered by Bikroelast, TechnoNIKOL, Linokrom, Bikrost. A significant disadvantage of bituminous material is its significant specific gravity.
Recently, non-perforated type vapor barrier films have become very popular, which are widely used to create both flat and pitched structures with various coatings:
- reinforced fabric on a polymer basis;
- reinforced films with double-sided lamination and a screen based on aluminum foil, the function of which is to reflect heat into the interior of the living space.
Laminated membranes are attached directly to the insulation layer from the inside of the room. At the same time, a distance of 4-6 cm from the inner lining is maintained: it is necessary for ventilation, since condensation can occur directly on the film due to the effect of vapors rising from the room.
Films come in different densities, differ in the level of flammability and resistance to ultraviolet radiation. The material used in them is completely safe for health, resistant to the development of mold and does not rot.
To remove excess moisture from the insulation layer, the latest generation of anti-condensate material is used - anti-condensate films. They are made on the basis of fleecy fabric, on the inside of which a special absorbent layer is applied, which retains accumulated moisture and contributes to its rapid weathering. The film must be in contact mainly with air, and not with a solid surface - otherwise it loses its performance.
When choosing a vapor barrier, you should pay attention to the highest quality material - super-diffusion breathable membranes. The distinctive properties of this ultra-thin material (layer thickness is from 0.2 mm) are lightness, strength, long service life of 30-50 years.
Superdiffusion vapor barrier can have two or three layers.
The components of the two-layer material are polypropylene fabric and one layer of polyethylene laminate.
The basis of a three-layer vapor barrier is mesh polypropylene, laminated on both sides with a polyethylene film.
Today's construction market also offers modified versions of membranes with an additional effect, designed for specific operating conditions.
Vapor barrier for a flat roof with a metal coating. This design is subject to significant surface overheating. For this reason, for seam roofs, as well as roofs with a coating based on metal tiles, profiles, films are used that do not lose their quality characteristics under the influence of high temperatures.
Application of reflective vapor barrier it is advisable in the case of the presence of powerful convection currents and if it is necessary to maintain the maximum possible amount of heat in the room. The metallic type coating perfectly reflects the heat rays that are characterized by increased intensity. Such materials are an ideal choice for a sauna or bath.
High strength films are applied at the device of roofs of the operated type. They are an excellent alternative to roofing material, besides they are smaller in thickness.
Vapor barrier material Izospan
This latest generation material creates a reliable vapor barrier and serves as an excellent protection for the insulation layer and supporting building structures from damage caused by condensate.
Installation of vapor barrier is carried out on the inside of the heat-insulating coating. The two-layer structure of the material provides reliable protection of the insulation and saves thermal energy in the building structure.
One surface of Izospan has a smooth texture, and the other has a roughness, due to which drops of condensate are held on it with subsequent evaporation.
The material prevents the development of mold, fungi that can cause significant damage to the wooden elements of the roof structure, and serves as an excellent protection of metal parts from corrosion.
Installation of Izospan is carried out on the supporting parts of the frame along the inside of the heat-insulating layer. Fastening can also be done on the rough sheathing using a simple stapler. The work takes little time, and the result is excellent during the operation of the roof.
The use of Izospan minimizes the likelihood of penetration of thermal insulation particles with a fibrous structure into the interior of the room.
Mounting
The vapor barrier of a flat roof is carried out in the process of installation work on the installation of roofing materials. Laying of the vapor barrier film is carried out after the installation of thermal insulation. For fastening to supporting structures, a construction stapler or special galvanized nails with a flat head are used.
Separate panels should be overlapped to each other with overlapping of the previous one by 10 cm and subsequent gluing with adhesive tape. It is also necessary to carry out thorough gluing in the areas adjacent to the protrusions of such building structures as antenna racks, chimneys, attic windows, ventilation ducts. Reinforced vapor barrier film can be laid on any surface to the heat-insulating material.
Having completed the laying of the vapor barrier on the logs, they begin to fasten the horizontal bars. It should be done every 50 cm. The function of the bars is to fix the vapor barrier layer and arrange an air gap between the interior finish and the film: its presence is necessary for the effective removal of accumulated condensate from the vapor barrier film.
Today, products of excellent quality are offered by the following companies:
- German DELTA;
- Czech JUTA;
- TYVEK (Luxembourg);
- TechnoNIKOL (Russia).
During the laying of a vapor barrier film on flat structures, there is a possibility of damage to it by materials in contact with it from above or below. Therefore, when installing roofing, extreme caution must be exercised.
FINDINGS:
- The main purpose of the vapor barrier layer is to protect against the ingress of water vapor rising from the room into the roof structure.
- A common mistake of inexperienced builders is the use of the same type of material for the installation of hydro and vapor barriers.
- The effectiveness of a vapor barrier material increases as its vapor permeability decreases.
- The main requirement for a vapor barrier system is absolute tightness.
- Today, a new generation of materials is used for the construction of a flat roof - vapor barrier membranes and films.
- To remove excess moisture from the insulation layer, anti-condensation films are used.
- The use of reflective vapor barrier is advisable in the presence of powerful convection currents and if it is necessary to maintain the maximum possible amount of heat in the room.
- High-strength films are used in the installation of roofs of the exploited type.
- Laying of the vapor barrier film is carried out after the installation of thermal insulation.
See in the video how to install a hydro-vapor-permeable membrane on the roof.