Arrangement of a roof with a cold attic. The specifics of installing a cold roof made of metal tiles How to make a cold roof correctly

Currently, when building a private house, specialists use all kinds of roof structures, but most often they install a cold roof. This is ideal when the attic is not planned to be used as a living space. Below we will talk about how to properly install a cold roof from a metal tile.

The advantages of this option

The device of such a roof is quite simple - you will need to build a structure, lay a layer of waterproofing, crate and counter-lattice, roofing. The main thing, when erecting a cold roof, is to provide a ventilation gap for the possibility of removing condensed moisture. This is necessary so that the supporting structure and roofing material do not deteriorate under the influence of moisture.

By itself, the installation of such a roof should not be accompanied by complications in the process of work, it is only necessary to correctly fix the roofing so that it does not let precipitation through the joints into the under-roof space. Before creating a roofing pie for a cold attic, you should complete the entire list of calculations, determine the slope of the slopes, the pitch of the crate, and choose the appropriate method for fixing sheets of metal tiles.

What is a cold roof

The technology of a cold roof made of metal tiles involves the initial construction of a truss system, after which a membrane and a plastic film will be laid on it to ensure. They fill the counter-lattice, the crate and lay the roofing in the form of a metal tile.

Such a roof is characterized by the fact that it does not need to lay thermal insulation - all that is required is to equip ventilation outlets under the ridge and on the slopes to remove moisture. Make sure that all preliminary calculations are made as accurately as possible.

Roof installation has the following features:

If over time you plan to equip a warm roof, then the choice of a membrane for protection against moisture should be careful. If it is planned to equip the attic, then a PVC membrane must be present.
If in the future it is not planned to insulate the roof, then it will be necessary to lay microperforated waterproofing, which is used specifically for cold roofs. Thermal insulation cannot be laid with such a film, however, in case of further insulation, it will be necessary to purchase a new membrane. Otherwise, in the future, the roof will lose its protection from moisture, the insulation will not have time to dry out, and the roofing material will begin to rust over time.

Installation steps

Let's figure it out so that it lasts a long time. When laying the membrane to protect against moisture, it should be borne in mind that it should remain with a slight sag, somewhere around 20 mm. In this way, it will be possible to achieve a runoff of condensed moisture, thereby protecting the rafter system and other roof elements from decay. To enable water to evaporate in time, without stagnation and thus creating an unfavorable environment, care should be taken to include a ventilation gap in the project, which is located between the moisture-repellent film and the roof ridge.

This implies that the clearance will allow air flows to easily circulate in the space under the roof, removing all condensate. The installed membrane must be free of ruptures and other damage. To fix it, it is best to use a construction stapler. The layers of the membrane are laid with a slight overlap, and its edges are sealed with adhesive tape.

The structure of the roof with a cold attic is such that it can be used in regions with any climatic features. Quite a few people believe that this type of roof is not applicable for the northern regions, although in fact it is not. Often in such regions, cold attic rooms are most often installed. The attic itself is insulated, and the cold roof in no way affects the internal microclimate of the upper floors. You don’t even need to use the attic, because laying a layer of insulation between the upper floor and the under-roof space eliminates all the nuances that affect heat loss.

When installing a cold roof made of metal tiles, it is necessary to take care of the thermal insulation of ventilation openings, chimneys and exits to the attic. In this case, it will be possible not to worry about the accumulation of condensate, icing, heat loss, or leakage of rain and melt water.

A cold roof can be covered with almost any roof covering, however, metal tiles, due to the ease of installation, are used much more often. Some other types of roofing materials, in particular soft roofing, are also well suited in this situation, but they require a lot of time and money during installation.

The structure of the roofing cake for metal tiles, including waterproofing

Covering a cold attic with a metal tile is the most convenient and easiest way to equip a roof. In this case, the roofing pie will consist of a waterproofing material laid on the rafter frame, battens and roofing (metal tiles). Actually, the laying of such a coating is carried out very quickly, the main thing is to understand correctly. The insulating film is fixed with staples or nails, then it is additionally pressed with a counter-lattice screwed with self-tapping screws. The lathing of the battens is carried out taking into account the dimensions of the metal tile. The board for the crate is taken with dimensions of 25-100 mm, and sometimes plywood or particle boards are used if continuous flooring is required.

Laying a film or membrane for attic waterproofing is done freely, with some sagging. However, it is worth making sure that the integrity of the coating is not violated, that is, any holes or cracks are excluded. As a rule, the film can sag by 15-25 mm. In this way, ventilation of the inner side of the waterproofing membrane is achieved, and condensed moisture is removed to the eaves and further to the drain. Neglecting such a simple rule will eventually provoke premature deformation of the roof frame and the entire roof.

The peculiarity of a metal roof is such that the film for a cold roof is not able to reduce the noise level that occurs during intense rain falling on the metal. Therefore, living quarters with such roofing are provided with a layer of thermal insulation that absorbs strong noise. Without such a layer, only non-residential attic spaces are usually equipped.

So, a cold roof will include the following layers:

From the inside of the room, a vapor barrier is laid for a cold roof, which only releases moisture to the outside and prevents it from penetrating into the living rooms.
Next, install the truss frame for the roof.
The next layer is mounted waterproofing material. The film is laid with sagging to drain condensate.
Next, a counter-lattice is attached, which presses the waterproofing, fixing it, and provides ventilation gaps.
Then the crate is stuffed to fix the roofing. It is made of slats 50 × 50 mm and is laid along the slopes with an indent of 35-45 cm. Based on the type of roofing and the slope of the slopes, the step of the crate and the thickness of the board for it may vary.
The last is the metal tile flooring.

Tools and consumables for a cold attic device

It is noteworthy that the laying of metal tiles does not require too complex professional construction tools. You can use the elementary set that every man has in his household.

In addition to lumber for the truss frame, battens and counter battens, an insulating membrane or film for vapor and waterproofing is required, as well as a sufficient number of metal tiles purchased from one lot.

All elements are fastened with brackets, self-tapping screws, galvanized nails and even anchor bolts. However, it is worth remembering that they must be of high quality so that the roof does not begin to collapse ahead of time.

As for laying roofing, in addition to profile sheets, ridge elements, valleys (internal and external), eaves and wind strips, as well as snow retainers and gutters will be required.

The main difference between a cold roof and a warm one is the presence in the latter of a layer of insulating material placed between the layers of hydro and vapor barrier. It is advisable to perform a cold roof only if the attic will not be used as a living space.

Today, in the construction of a residential building, various options for roof structures are used, but the simplest is a cold roof. Such a device is great when the attic space is not used as a residential additional space. The very scheme of such a roof is very simple: load-bearing structures, waterproofing, lathing and counter lathing, plus roofing material.

The features of the installation of such a cold roof are that it is necessary to provide a ventilation gap for the removal of condensate in order to protect not only the supporting structures, but also the roofing in the form of a metal tile from the negative effects of moisture.

The installation of such a roof itself does not differ in any difficulties, the main thing is to properly fix the profiled metal sheet so that precipitation does not penetrate through the joints under its surface. Before starting construction, you should make all the required calculations, calculate the angle of inclination, the step of the crate, decide on.

Features of a cold roof

A cold roof differs from a warm one in its design, although its design itself is extremely simple. The only thing to consider is the option of roofing. When using metal tiles, it is necessary to provide a ventilation gap for the correct removal of condensate from the under-roof space. This is done so that the steel sheet does not corrode.

The device of a cold roof is the installation of a truss system, on which a membrane or plastic film is laid for waterproofing. After that, a counter-lattice, a crate and a coating in the form of a metal tile are nailed.

The features of such a roof are the complete absence of a layer of heat insulator, the presence under the ridge and on the slopes to remove moisture. Design and installation are not difficult, the main thing is to correctly carry out all preliminary calculations.

The installation itself includes the following features:

If it is planned in the future, then it is necessary to approach very carefully the choice of a membrane to protect against excess moisture. For the future attic, only specialized waterproofing in the form of membranes made of PVC is suitable.
If further insulation is not planned, then microperforated waterproofing is used, designed specifically for cold roofs. Such a film does not allow thermal insulation materials to be laid next to it, that is, with further insulation, you will have to spend money on a new membrane. If this condition is not met, then the roof will practically not be protected from moisture in the future, the insulation will be constantly wet, and the roof covering will be subject to corrosion.

Sequence of work

To lay the waterproofing membrane, it must be remembered that its installation is carried out with some sag, approximately 20 mm. Such a device allows the condensate to drain, that is, the rafters and other roof elements are protected from moisture. In order for the water to evaporate effectively, and not to stagnate, creating an unfavorable atmosphere, it is necessary to ensure the presence of a ventilation gap, which is made between the waterproofing film and the roof ridge.

Such a gap allows air to circulate unhindered in the under-roof space, removing all traces of condensate. The roof protection membrane itself should not have ruptures or other defects; it should be fixed using a construction stapler.

Be sure to overlap, the edges of the film must be fixed with adhesive tape.

Of the features that distinguish a cold roof, it should be noted that it can be built for any climatic region. Many mistakenly believe that this type of roof is completely unsuitable for the northern region, but this is not so. It is here that a cold attic is a traditional solution for a residential building. The attic floor itself is insulated, that is, the use of a cold roof does not affect the internal microclimate of the upper floors. The attic itself may not even be used, since the installation of a layer of insulation between the upper floor and the under-roof space solves all problems regarding heat loss.

When constructing a cold roof, one should not forget about such a stage of work as the correct insulation of technological openings and exits. To do this, all ventilation shafts, chimneys, entrances to the roof surface must be insulated. This will avoid such troubles as icing, condensation, penetration of precipitation, heat loss.

To cover the roof of this design, you can use a variety of roofing materials. Most often it is a metal tile, the installation of which does not pose any problems. This option is considered optimal, since all laying work is carried out in the shortest possible time, no additional work is required. You can use other materials for coating, for example, flexible tiles. But here a number of technological difficulties already arise that can make installation more expensive and complicated. Therefore, the use of a metal profiled sheet is preferable in this case.

Roofing pie under the metal tile

The device of a cold roof under a metal tile is one of the simplest options. In addition to load-bearing structures, such a roof includes roofing material in the form of metal tiles, a crate, and a waterproofing layer. The installation of such a roof is very simple: a waterproofing film is attached to the rafter system using a construction stapler or small galvanized nails. After that, it is pressed with self-tapping screws on wood, with which the counter-lattice will be attached, the step of which depends on the type of metal tile sheet. The size of such boards should be 25 by 100 mm, in some cases a continuous coating of plywood or chipboard sheets is used.

A waterproofing film (it can be a special PVC membrane or a polyethylene film) should be laid on the roof with a slight sag. At the same time, gaps and other defects are unacceptable on it. The level of sagging of the roofing film should be from 15 to 25 mm. This will ensure proper ventilation of the underside of the waterproofing, removal of condensate from it to the eaves, and then to the gutter. If this is not done, it will be subject to the negative effects of moisture, and this will lead to destruction.

When installing a cold roof made of metal, it must be remembered that the metal sheet and a thin layer of waterproofing do not provide adequate protection against noise, which can occur during heavy rain. It is for this reason that cold steel sheet roofs are rarely made without insulation, which acts as an excellent sound insulator. The cold attic therefore turns out to be unused.

The structure of such a roof includes the following mandatory layers:

From the side of the residential premises, first there is a layer of vapor barrier with one-sided permeability, that is, condensate is released from the room, but does not penetrate inside.
Roof truss system, longitudinal runs, that is, the supporting structure.
Waterproofing. The film should sag a little to allow condensation to escape.
A counter-lattice, the installation of which is carried out parallel to the installed rafters. The boards of the counter-lattice press the waterproofing, providing its additional fastening.
The lathing of the cold roof is made of a wooden beam, the cross section of which is most often 50 by 50 mm. Its installation is carried out in increments of 35-45 cm along the slopes. The step may vary, as well as the material for the crate, it depends on what type of metal tile is used, what slope for the roof was chosen.
Sheets of metal tiles.

What else is required?

To install a roof with such a design, it is necessary to take the simplest tools and materials that do not differ in high cost. In addition to wooden boards for the rafter system, battens and counter battens, a vapor barrier, a waterproofing membrane, and an estimated number of metal tile sheets should be prepared. Staples, galvanized nails, self-tapping screws for wood and metal are used as fasteners. When calculating steel sheets, it must be remembered that various additional elements may be needed, for example, ridge tiles, valleys, cornices, and so on.

The device of a cold roof differs from a warm one in that in this case a layer of insulation is not used, that is, there is no layer of insulation between the vapor barrier and the waterproofing membrane. Such roofs are applicable in the case when the attic space under them is not used.

Comfortable living in the house is impossible without a well-equipped roof. In order to reduce heat loss in the cold months of the year and create a favorable microclimate for people staying in the house, different materials are used, including corrugated board.

Thanks to the multi-layer roofing cake containing a layer of thermal insulation, heated air does not leave the premises in cold weather. Installation of a vapor barrier under corrugated roofing helps to maintain low thermal conductivity.

Why do I need a vapor barrier under corrugated board

Many homeowners are interested in whether it is possible to cover the roof with corrugated board without waterproofing, and why it is needed.

The vapor barrier layer in this case is equipped to achieve certain goals:

To protect the insulation from the penetration of wet fumes. The fact is that as a result of its wetting, an increase in thermal conductivity occurs. In addition, the penetration of moisture leads to the destruction of the material.
To prevent the accumulation of liquid in the thermal insulation layer and the direction of water vapor to the outside.

Water vapor is always present in the air of residential buildings. They are partially removed from the premises by the ventilation system, while the rest remain. Steam-saturated warm air rushes to the ceilings, where it cools, and the moisture that has appeared penetrates into the roofing materials.

The insulation has a porous structure and therefore absorbs wet fumes. In the process of getting wet, the thermal conductivity of the material increases, and it retains heat worse in the house. To prevent the penetration of moisture into the porous structure of the insulation, a vapor barrier is mounted under the corrugated board.

A film for arranging a vapor barrier layer is placed on the side of the premises in order to protect the material for thermal insulation and elements of the roof structure from vapor penetration.

Features of the choice of material for vapor barrier

The building materials market has a wide range of special films for mansard and cold roofs used for the construction of a vapor barrier layer.

In order to make the right decision as to whether a vapor barrier is needed for corrugated board, it is necessary to have information on a number of factors:

Before purchasing materials for profile flooring, it is necessary to deal with the financial side of the construction. If the defining moment is the price, then choose economical products.

In terms of efficiency, vapor barrier films differ in performance and should be familiarized with in advance.

When choosing a material, the characteristics of a particular room are taken into account. For a heated building, a foil film will be the best purchase, but for a cold roof made of corrugated board, inexpensive glassine will be enough. When a roof is erected on a building that is visited occasionally, a vapor barrier made of polypropylene or ordinary polyethylene film will be required.

Vapor barrier products for the roof

To lay a layer of vapor barrier under corrugated board or other roofing, films are used.

The following most popular types are presented on the construction market:

polyethylene film. This inexpensive household material has long been used as a vapor barrier. It delays the steam coming from the living quarters. Polyethylene is cheaper than membranes and reinforced films. It has a big minus - insufficient strength, since it can be easily damaged during installation. To make the insulation reliable, the film is laid out in two layers. It is attached with a special stapler to the inner crate, observing a step of 1.0–1.5 meters. In case of damage to the material, a patch must be made. To do this, the puncture site is sealed with construction tape. You should also fix the joints.
Reinforced polyethylene. It is inexpensive but of good quality. It is made from several layers of polyethylene and reinforced with a polypropylene mesh for strength. Despite the low weight, such a film is strong enough and it is more difficult to damage it during the fastening process. Due to the reinforcement, the material is more rigid. The film is fixed with a special tape. The choice of this material can be called the optimal combination of affordable price and good quality.
glassine. It has been used to create a vapor barrier for a long time. It is a reliable protection against moisture, is durable, has a long service life, but, unfortunately, it has a lot of weight. Despite the cheapness, glassine is not recommended for use in residential areas. In case of heating, the material begins to emit an unpleasant odor, and after laying the corrugated board, its temperature rises frequently. For the reason described above, glassine is used when the answer to the question of whether waterproofing is needed under the corrugated roof of a cold roof of a non-residential attic is positive. It is convenient to use for laying waterproofing over the crate.
Polypropylene film. It is a durable material for vapor barrier laid under profiled sheets. It is produced in a similar way to a polyethylene multilayer film, but it has an embossed layer. On films with a smooth surface, condensation accumulates, then it collects in drops and from time to time they fall to the floor. A film with a rough surface is produced on the basis of cellulose and viscose. It is able to absorb moisture and this feature prevents the formation of drops. Further, under the condition of lowering the humidity of the air, the collected condensate evaporates. Mount the film with an anti-condensate surface to the room. For the correct installation work, you must study the instructions from the manufacturer of the product. This type of film is one of the best options for a vapor barrier under a profiled sheet.
foil. At its core, it is a kind of polyethylene or polypropylene products. She has not only a reinforcing mesh, but also a thin layer of aluminum that reflects infrared rays and helps to keep warm. As a result of using a foil film, heat loss is reduced by more than 10%. The cost of such an insulator is higher compared to other types of vapor barrier materials, but its installation allows you to save on heating costs. The foil film is laid with an aluminum coating towards the room. Between it and the wall decoration should leave a gap of about 5 centimeters. There should also be a small gap to the insulation. To fix the film, self-adhesive tape is used, and the joints are covered with aluminum tape, and then the vapor barrier layer is sealed.

Waterproofing cold roofs - is it necessary?

The space under the cold type roof is not heated, but the temperature inside is always different from the outside. For this reason, condensate collects from below the profiled sheets. Therefore, the answer to the question: “When a cold roof is being built, is waterproofing necessary?” unambiguous. Of course it is.

This layer will prevent moisture vapor from entering the wooden elements of the truss system and other parts of the roof structure. Waterproofing is laid on top of the rafters and then fixed with a counter-lattice. Next, mount the crate and profiled sheet.

When the waterproofing layer does not prevent steam from escaping to the outside, then there is no need to equip a vapor barrier for a cold roof. Rising up, water vapor enters through the film under the corrugated board and dries up in that place due to the movement of air flows. In this case, roofing material, polypropylene, glassine and polyethylene are not suitable. For a cold roof, experts recommend using a non-woven vapor permeable membrane.

Vapor barrier device

Do I need a vapor barrier for a cold roof? No, because it is equipped only for warm roofs, so that moisture does not get into the insulation.

The panels of the vapor barrier layer are laid with an overlap of about 15 centimeters. For the selected type of film, a connecting tape is selected. Small slats for her can be wooden or metal.

Vapor barrier under corrugated roofing: is it necessary to waterproof a cold roof, can it be covered without it under a corrugated sheet

Everything you need to know about choosing a vapor barrier for cold and mansard roofs

When planning your home project, you always want it to be warm and cozy.

To do this, follow the instructions when carrying out construction work.

Also, enough attention must be paid to the insulation of the roof, in particular, the competent provision of all types of insulation.

How to choose a vapor barrier for the roof and not make a mistake? First, let's get acquainted with the types of vapor barrier materials.

What is vapor barrier?

In residential premises there is always water vapor that circulates inside it. And according to the laws of physics, it rises with warm air. Over time, it will penetrate into the under-roof space, where it starts absorbing heat.

To avoid these consequences, it is necessary to install a vapor barrier, which should be present in any roofing cake. Some believe that finishing the attic with a cladding that prevents moisture from entering eliminates negative consequences. But it is recommended to always use a special coating, which is placed between the ceiling and the insulation.

What vapor barrier to choose for the roof?

There are the following types of vapor barrier for the roof:

Painting shop

Used more frequently for high-rise buildings, soft roofs made of roofing felt, iron roofing sheets, where insulation is not used. This vapor barrier is well suited for flat roofs. The main difficulty in using mixtures of this kind is the preparation of the surface before application. For this type of insulation, the following compositions are used as:

hot bitumen;
bitumen-cookersalt mastic;
varnish based on chlorinated rubber or polyvinyl chloride.

Pasting (membrane)

This species is more popular, especially in individual construction. Materials for this kind of insulation are produced in rolls and this provides some advantages:

simplification of styling;
ensuring a tight connection when overlapping;
reduction in the number of seams.

Types of pasting vapor barrier materials

waterproofing. Prevent the penetration of steam into the insulation. Have a special perforation which allows vapors to escape. It is mounted with a certain gap from the roofing, which promotes air circulation between the outer and under-roof space. Possesses unidirectional steam permeability, keeps thermal insulation dry.
Anti-condensation. Equipped with a special fleecy layer, which is located on their inner surface. It retains moisture and prevents ingress on thermal insulation. Moisture quickly disappears due to air circulation in the gap. This type of insulation should be laid with an absorbent layer towards the interior of the room. Fastened with a counter-lattice.
Vapor proof. Provide impenetrable protection to the inside of the roof insulation. Sometimes they have a layer aluminum foil, which is capable of reflecting some of the radiant energy back inward. Fitted with a ventilation gap to the insulation. Provides good protection against moisture, while retaining heat.
membranes. They are modern vapor barrier materials that can prevent moisture from escaping, while passing air. When using membranes, an air gap is often not necessary. This material for roof vapor barrier has gained great popularity these days.

Special arrangement of such roofs does not require laying two layers: thermal insulation and vapor barrier. This saves money and building resources. Water vapor that passes through the film is between the waterproofing and the corrugated board, from where it is removed by the air flow.

Therefore, the main task when installing a cold roof is ensuring good ventilation, which is provided by creating a gap with the help of a counter-lattice.

Cold roof device

Do I need a vapor barrier under the corrugated roof of a cold roof? No, it is not needed, the main thing is to take care of good ventilation.

Vapor barrier for mansard roof

The most commonly used materials are: glassine, roofing material and foil insulation. Modern membranes are also quite effective., which have proven themselves in this sector and are excellent for the vapor barrier of soft roofs.

First of all, it is necessary to seal and insulate various structural elements. The vapor barrier is laid on the insulation and fixed by a method that corresponds to the surface material.

Fastening to concrete, brick and metal surfaces is carried out using double-sided adhesive tape, laid with 10 cm overlap. And it is attached to the tree with nails or stapler staples.

The foil film is installed with a reflective layer inside the room so that the thermal energy remains inside the building. Between the heat-insulating and vapor barrier part, a gap is provided for ventilation, as well as to create a warm air barrier.

Detailed diagram of the roofing pie of the mansard roof

The joints of the film are glued with adhesive tape from a material with a close coefficient of thermal expansion. It is better to press the junctions of the foil to the wall with planks with a sealant applied under them.

Vapor barrier under corrugated board or metal tile

The metal tile is a heat-conducting coating, therefore, with the onset of cold weather, condensate causes irreparable harm to it. To solve this problem, it is necessary to provide the roof with competent vapor barrier and waterproofing. Before choosing, you should decide which is more important: price or efficiency? Let's look at which vapor barrier is best for a metal roof:

Cheap option - glassine and polyethylene

glassine can last a long time, while has sufficient flexibility and low cost. However, its large mass, unpleasant odor when heated, and installation difficulties make it not the best option.

Polyethylene retains steam well and protects the heat-insulating layer from moisture. It is cheap, but polyethylene is very easy to damage. It is difficult to mount it yourself. Due to the significant mass, it is difficult to install the film by the standard method to the corrugated board. Therefore, installation takes place to the inside of the cladding using a stapler. The film is mounted in two layers.

Reinforced film, foil, membranes

In terms of price, it is also an acceptable option. Reinforced film consists of several layers with a reinforcing fabric mesh that adds strength. Light weight and rigidity allow you to install such insulation yourself. Fastened with self-adhesive tapes. A significant drawback is the lack of an anti-condensate layer, which can adversely affect the insulation.

Scheme of the device of a roof from a metal tile

What vapor barrier to choose for a roof under a metal tile? One of the best options is foil. It has a low heat permeability, which allows you to keep warm in the room, low weight and sufficient strength. The big disadvantage of this material is the tendency to form corrosion.

Conclusion

The penetrating power of steam is sometimes underestimated, which leads to a rapid failure of thermal insulation. Therefore, it is necessary to responsibly approach the issue of vapor barrier and take into account all the nuances when choosing materials and carrying out work. This will ensure a long service life of the future building.

Which vapor barrier to choose for the roof: choose a vapor barrier for a flat, attic, cold roof

Not sure which vapor barrier to choose for your roof? We will tell you about the types of vapor barrier for the roof, consider whether a vapor barrier is needed for a cold and mansard roof. We will also talk about which vapor barrier material is suitable for a flat roof and a roof made of corrugated board and metal tiles.

Do you need a vapor barrier under a cold roof?

Today, more and more developers are asking this question. The fact is that a cold roofing system allows you to build a residential building for relatively little money, when an insulated roof requires enormous costs both financially and in terms of time and effort. Realizing that such a system is in a sense better, many developers have wondered if a vapor barrier is needed under a cold roof?

Cold roof construction in a residential building

Many developers who want to save some money on construction seek to purchase the cheapest materials, but at the same time, so that the quality of the entire building does not suffer much from this. This is possible if primitive two slopes are used as a rafter system, corrugated board as a covering, and the roof is made cold.

The design features of such a roof can be listed on the fingers, since there is no need to lay heat-insulating material, a vapor barrier layer and other components that are often found on insulated roofs. If you all doubt the savings, then it is safe to say that the cold version will cost 50-60% less than the insulated design. In addition, the work can be carried out independently, therefore, the savings will increase even more.

A cold roof pie, in most cases, includes the following products:

rafter legs
waterproofing material
Control lathing
crate
Profiled metal sheet

Do I need waterproofing under the metal roof of a cold roof?

It is worth noting that all metal surfaces have one similar feature, they collect condensate. Waterproofing, which is part of the roofing pie with a cold roof, will correct this problem and protect the room from incoming moisture, both from the outside and from the inside. Many developers, when building an insulated roof, advise their friends not to lay a vapor barrier layer if they are building a building with a cold type of roof. They think that the cold will remove the condensation that is visible on metal products, but they are greatly mistaken.

Condensation occurs due to the temperature difference between the roof space and the external environment. Naturally, when the attic is not heated and not insulated with anything, the difference will be small, but still it is sufficient to provoke the release of moisture from the air. As you can see, condensate will form regardless of the type of roof, therefore, the question posed at the beginning of the paragraph can be answered unequivocally: yes, it is needed.

An example is outbuildings, the owners of which do not care much about their service life. In such buildings, the roofing cake is the most primitive and even violates building codes and regulations. Most often, a roofing cake consists of rafters, discharged lathing and roofing. All layers of vapor barrier and waterproofing were simply thrown out. Despite this fact, this building can stand for a significantly long period, or vice versa, fall apart after a couple of years. Here you are already lucky, but why take risks if you can do everything in a quality way?

Risks cannot be allowed on residential buildings, as someone's life may depend on it. I am not exaggerating, because if the condensate affects the rafter system and other roof elements for a long time, it will simply destroy them, which can lead to the fall of the entire roofing pie.

Waterproofing and ventilation of a cold roof

If you are laying a micro-perforated product, then such a layer will block moisture from the outside, but water vapor can pass through this area without problems. It can be said that the installation of vapor barrier products on roof slopes is not necessary in this case. After the steam penetrates inside, it is between the waterproofing material and the metal coating, from where it is removed by natural ventilation.

With increased air humidity, condensation processes begin, so moisture accumulates on the reverse side of the film and penetrates into all roofing materials. In connection with this fact, it is not recommended to use materials such as polyethylene and polypropylene, roofing felt, and glassine for the construction of a cold roof.

The ventilation system of cold roofs is quite simple. To create it, gaps are left, which, as a rule, are located along the cornice overhang. Air masses pass through them, collect all the humidified air and remove it through a cold triangle located in the ridge part of the roof.

The counter grille is a design to provide additional ventilation. Most often it can be found on complex roofing systems, where products with a high degree of waterproofing are used as a coating, for example, metal, shingles and others. The gap that is created by installing a counter-batten allows fresh air to dry the roofing pie from both sides, so structures with such a pie last much longer than the others.

Cold roof. Do buildings need waterproofing?

First of all, it should be noted that outbuildings differ significantly from residential buildings both in their structure and volume. The vast majority of developers are trying to save on the construction of secondary structures, so the issue of waterproofing is more relevant than ever. Before answering the question posed, let's deal with the coverage. To date, corrugated board is one of the cheapest materials, so I will talk about buildings covered with it.

Manufacturers from different countries are striving to produce such products so that the whole world begins to use it. If you are a fan of corrugated board, then today, such material is a sheet of metal with an anti-condensation coating.

In its appearance, it practically does not differ from its counterparts. A synthetic composition is applied from the inside, it looks like felt. Due to the large number of pores, this material is able to retain up to 1 liter of water per square meter. After the surface has been saturated with moisture, ventilation comes into play and if it is done in accordance with all the rules and regulations, then the drying process will not take much time.

Thanks to the laying of such a “cunning” coating, the need for laying a vapor barrier and waterproofing layer is removed, but it should be understood that the weight of such a coating will vary depending on weather conditions. When making the necessary calculations, it is very important to take into account these parameters and use them in the calculations. It is worth noting that the finished roof will be much cheaper, because it will not have almost half the roofing cake.

Installation of waterproofing for a cold roof

So, based on the information obtained above, you realized that the waterproofing material is laid regardless of the type of roof and the functional purpose of the building. However, if you want to save money, you can use roofing with an anti-condensation layer, but not all people like metal coatings, so I will now tell you the general principle of laying waterproofing.

First of all, an inexperienced roofer must repeat the safety precautions and the principle of working at height. After that, he puts on a special uniform, which should include the following: personal protective equipment, good shoes with non-slip soles and a mounting belt.
After the rafter legs are fixed in place, you can start laying the vapor barrier layer. It is attached to the rafters with a construction stapler and pressed against the crate. With a small slope, the strips of material are placed across the slope, and along the strongly sloped slopes. To improve the quality of laying this layer, the joints are smeared with bitumen or glued with double tape.

Next, the counter-lattice is laid. It creates the necessary air gap, thanks to which moisture will be removed from the roofing cake.
A waterproofing material is laid on top of the konroblattice.
After that, proceed to the installation of sheets of corrugated board.

Most developers strive to cover as much length as possible with one strip of profiled sheet. This is justified by the fact that in this way fewer joints are obtained, therefore, the waterproofing qualities of the entire roof increase significantly. You can do all the work yourself, but to increase efficiency it is better to invite 1-2 partners.

Do I need a vapor barrier under a cold roof: waterproofing under a metal tile

If you are wondering: do you need a vapor barrier under a cold roof? Then after reading this article you will understand everything. It describes the nuances of insulation and the technology of laying suitable materials.

Cold roofing from corrugated board: device and technology

A house with a cold attic is far from uncommon in modern construction. This solution is especially relevant for outbuildings, as well as cottages. Often a cold corrugated roof is also made in residential buildings, when the main area of \u200b\u200bthe house is enough for its owner and there is no need to make an attic.

The device of a cold roof is expedient, first of all, for economic reasons. Firstly, you save on materials, and secondly, by isolating a large under-roof space from the rest of the house, you do not spend money on heating it. And thirdly, installing a cold roof is much easier than laying a full-fledged roofing pie.

The device of a cold roof from corrugated board in a residential building

The design of a cold roof is very simple. On slopes, neither insulation, nor vapor barrier, nor, moreover, finishing is needed. Naturally, the savings in this case are very significant, given that the price of thermal insulation and finishing is 50-60% of the cost of the entire roof. In addition, due to the simplicity of the design, a do-it-yourself cold roof made of corrugated board fits without any problems.

The cold roof pie consists of the following elements:

Rafter;
Waterproofing film or membrane;
Counter grille;
crate;
Decking.

Cold roof waterproofing: is it necessary?

Waterproofing a cold roof will protect the room from possible leaks and condensation that forms on the inside of the metal roofing. Since condensate is released on metal surfaces during temperature changes, there is a common misconception that it will not occur when an uninsulated corrugated roof is installed.

Naturally, such an opinion is not true, because, despite the fact that the roof space is not insulated and heated, the temperature inside will still differ from the temperature outside, and often quite significantly. Therefore, the answer to the question: “Will there be condensation on the corrugated board if the roof is cold?” - unequivocal: "Yes, it will."

In this regard, it becomes obvious whether waterproofing is needed under the cold roof corrugated board. The consequence of its absence will be that the condensate will fall on the ceiling, increasing the humidity in the attic. This will lead, at best, to accelerated damage to wooden structures, and at worst, to a catastrophic decrease in the heat-insulating properties of the insulation if it is unprotected.

The waterproofing membrane of the cold roof is laid on the rafters and fixed with a counter-lattice, after which the crate is already mounted for the installation of corrugated board.

If you are not going to insulate a cold roof in the future, then microperforated film can be used as waterproofing, which is much cheaper than special membranes. However, it must be mounted with a mandatory sag of 20-30 mm so that moisture flows into the space between the rafters, and does not moisten them, seeping through due to the capillary effect.

Vapor barrier and cold roof ventilation

Since the micro-perforated films prevent the penetration of moisture from the outside, but do not interfere with the passage of water vapor, vapor barrier of a cold attic on the roof slopes is not required. Water vapor, passing through the film, is between the waterproofing layer and the corrugated board, from where it is removed by the air flow.

If the waterproofing film for a cold roof retains water vapor, this will lead to excessive moisture in the room and, as a result, dampness. In addition, with increasing humidity, steam will condense already on the film from the inside. Therefore, ordinary polyethylene and polypropylene films, as well as outdated materials such as roofing material or glassine, are not suitable for waterproofing a cold roof.

Ventilation of a cold roof is very simple and is ensured by creating a gap with a counter batten: the air flow enters under the roofing through the eaves and exits through the ridge.

The presence of a counter-lattice is a prerequisite for good ventilation. It is this gap of several centimeters between the film and the crate that allows the air flow to pass unhindered under the roofing.

Ventilation of a cold attic is carried out using conventional dormer windows, which should be located in such a way as to ensure the passage of air flow during ventilation through the entire room. If the dimensions of the roof space are large, the ventilation of a cold attic in a private house can be improved using a classic supply and exhaust scheme.

If you are planning to insulate a cold attic in the future

In the event that a cold roof made of profiled sheet is a temporary option, and in the future you plan to insulate it to create a full-fledged living space, microperforated film should not be used as waterproofing. The fact is that it is impossible to mount a heater close to it - if this is done, the film will lose all its waterproofing properties and begin to let water through.

This film must be replaced with a non-woven vapor permeable membrane. In particular, those types of Tyvek or Dorken membranes that can be laid directly on the insulation are perfect for these purposes. Of course, they are more expensive, but their use will reduce the thickness of the roofing cake by 80-90 mm. If you already use micro-perforated foil as waterproofing for a cold corrugated roof, you must ensure a gap of at least 50 mm between its lowest point, taking into account sagging, and thermal insulation.

In addition, the vapor barrier of a cold roof converted into an insulated one is not needed, since the steam will pass through the insulation and, without lingering in it, will be removed through the film or membrane.

Cold roof from corrugated board in utility rooms

For sheds, change houses and other utility rooms, a cold roof made of profiled sheet is the best option. In this case, it is recommended to use a special corrugated board with an anti-condensation coating.

Such a profiled sheet is coated on the reverse side with a special synthetic composition, which is similar in structure to felt. Due to the large number of small air cavities, this material can hold a fairly large amount of moisture - up to 1 liter per m2. Thus, with an increase in humidity, the anti-condensation coating absorbs water, which then evaporates under the action of cold roof ventilation.

Thanks to the use of a profiled sheet with an anti-condensation coating, the design of a cold roof becomes much simpler and cheaper, since neither waterproofing nor a counter-lattice is needed. In addition, such material is indispensable for gazebos, verandas, sheds and other open structures, since waterproofing is not used in them in principle, and condensate appears no worse than in a cold attic.

Installation of a cold roof from corrugated board

The cold roof of a house from a profiled sheet is easy to install and can be easily assembled by hand without the involvement of specialists.

First, waterproofing is mounted, with sagging, if microperforated film is used as it. It is fixed with the help of bars of the counter-lattice, nailed to the rafters parallel to them.

Then the crate of the house is performed.

Next, the direct installation of a cold roof from corrugated board is carried out. If the width of the roof slopes is less than the maximum possible length of the corrugated sheet, then it is laid without transverse joints at all, which improves the tightness of the coating. Side joints are made in 1-2 waves, depending on the slope of the roof and the grade of the profiled sheet.

The technology of a cold roof is quite simple, so its installation is carried out quickly enough. However, all the wooden components of the roof must be pre-treated with special compounds that will prevent them from rotting, as well as from mold and fungus.

How to insulate a cold roof?

Often the device of a cold attic is just an intermediate stage. Most cold roofs are insulated over time in order to increase the living space of the house. This is easy to do, since there is no need to redo the cold roof pie - it is, in fact, the top of the insulated roof pie.

In order to make an attic out of a cold attic, you just need to add a layer of insulation and finishing. If, as we recommended, you used a waterproofing vapor-permeable membrane as a waterproofing, and not a microperforated film, then the material for thermal insulation is laid tightly between the rafters. Then an internal crate is made with bars of the required thickness, between which a second layer of insulation is mounted. They can also be fixed finishing - wooden boards or drywall.

When insulating a cold attic, a vapor barrier layer is not needed, since water vapor from inside the room will pass through the insulation and exit the roofing pie through the waterproofing membrane into the under-roof space. Therefore, before insulating a cold roof, do not forget to treat all internal wooden structures with rotting compounds.

In addition to this method, insulation of a cold roof attic can also be performed using polyurethane foam spraying. This is one of the fastest and easiest options, and it is also considered one of the best insulation on the market. It is fireproof, has excellent heat-insulating properties, is durable, resistant to acids and alkalis, and does not rot.

In addition, the insulation of a cold roof from corrugated board with polyurethane foam allows you to create a continuous layer of thermal insulation, in which not only there will be no gaps, but also the rafters will be closed. The only downside to this method is the cost. Also, you will not be able to do this work yourself, because it requires expensive equipment.

Cold attic device: ventilation, waterproofing, insulation

The device of a cold roof in a residential building and utility rooms: technology, features and ways to save. How is cold roof waterproofing and attic ventilation carried out? How to insulate a cold corrugated roof?

The device of a cold attic in a building involves, as you know, the use of a lightweight version of the roof, which is also called "cold". A characteristic feature of such roofs is the absence of a layer of insulation in them, which is mounted between the vapor barrier layer and the membrane waterproofing.

Note! This type of coating is usually made in cases where the attic space located under them is not residential and is used only as an auxiliary room.

Thus, the implementation of the cold attic project is usually reduced to the arrangement of the roof, which should include the following elements:

roofing material of your choice;
protective waterproofing layer;
main crate;
counterlattice.

The presence of an additional crate with a waterproofing layer attached to it entails the formation of free spaces used as ventilation ducts that protect structural elements from condensate.

From a purely technical point of view, the installation of roof structures of this type is quite simple. When organizing it, due attention must be paid to the choice of roofing material that provides the required surface tightness and excludes the possibility of moisture penetration to wooden structures.

Roofing from a metal tile

Preparing a "cold" roof for a metal tile is the simplest and most convenient option for its arrangement, as a result of which a kind of cake is obtained from roofing material, a waterproofing layer and wooden crates.

The preparation of such a roof is not particularly difficult and includes the following simple operations:

First of all, a waterproofing film is hemmed to the rafters with the help of small nails or a construction stapler.
Then this film is covered with boards of a counter-lattice, which is mounted on the rafters using wood screws (the selected installation step depends on the size of the metal tile sheet).
In some cases, to prepare the surface of the counter-lattice, a continuous coating is used, recruited from sheets of moisture-resistant plywood.

As a waterproofing layer, a special PVC membrane or an ordinary polyethylene film can be used, fastened at its location with a slight sag (from 15 to 25 mm). Such sagging creates conditions for ventilation of the waterproofing layer and removal of the condensate formed on it towards the eaves (gutter tray).

You should pay your attention to a number of conditions that must be considered when arranging a cold roof. Firstly, the boards of the counter-lattice must be packed parallel to the rafters used as the base of the entire structure, thereby providing additional fastening of the waterproofing hemmed to it.

Secondly, the lathing of such a roof should be made of a wooden beam with a section of 50 × 50 mm, installed in increments of 35–45 cm along its slopes. In this case, the choice of the step size (as well as the material for the crate) depends on the type of metal tile you use, as well as on the angle of inclination of the blood.

When installing a cold attic under the tiles, it should be understood that a thin metal sheet and a waterproofing layer will not provide you with proper sound insulation. At the same time, the noise level in the under-roof space (during heavy rain, for example) due to the lack of a layer of insulation can significantly exceed the value normalized in SNiP.

Some subtleties of roofing installation

Experienced experts advise paying attention to the following circumstances of arranging a cold attic:

In the event that you plan to insulate the attic space in the future, it is necessary to approach the choice of a moisture-proof membrane with full responsibility. The best option in this case is the use of a waterproofing layer in the form of a PVC membrane.
If roof insulation is not expected in the near future, it is best to use a micro-perforated waterproofing film designed specifically for cold roofs.

The fact is that when using such a film, its contact with insulating materials is unacceptable, therefore, in the case of insulation, you will first have to dismantle it and only after that lay a new waterproofing. If this condition is not observed, the required reliability of the structure protection is not guaranteed by the manufacturer, and the insulation placed in the "pie" will be exposed to moisture.

Among the materials present on the Russian market, most often used for arranging a cold roof, the following items can be distinguished:

superdiffusion membrane brand "TechnoNIKOL";
polymer coatings under the names "Pural" and "Prisma";
metal tile brand "Supermonterrey".

The product under the name "TechnoNIKOL" is a film membrane consisting of 2 layers of non-woven polypropylene and a layer of polypropylene film and providing the possibility of one-sided vapor diffusion.

Pural polymer coating is a membrane-type material made on the basis of polyurethane and has excellent anti-corrosion properties. In addition, it is resistant to mechanical stress and can be operated in a wide temperature range.

A product called "Prism" (UK) is a film metallized coating, consisting of 95% zinc and only 5% aluminum. The addition of aluminum to the material makes it possible to increase its protection against corrosive and mechanical influences.

The multi-colored tile covering "Supermonterrey" is made in the form of metal sheet blanks of a standard size, having a thickness of about 0.5 millimeters.

Video

This video provides an overview of cold roof materials:

Most pitched roofs in our country have a cold attic in their design. This name is due to the air temperature in the attic, which should not differ much from the air temperature outside the house. With such an arrangement of the attic, a sufficiently large buffer air zone is formed, which allows you to effectively control the temperature in the attic with its proper arrangement.

Cold loft design

When building the roof of a house, many people think about making a cold attic or attic under it? The easiest way to organize a roof with a cold attic. Building an attic will cost several times more and will require more labor costs.. Although, it is undeniable that the attic will significantly expand the living space.

Cold loft roofs have the following main ingredients in their pie:

roofing;
attic outer walls (applicable for gabled roofs with gables);
insulated ceiling between living space and attic.

Ventilation is provided by eaves and ridge ducts. The air passing through the cornice openings is called supply air, and the air exiting through the ridge is called exhaust air. Additionally, ventilation can be done through dormer windows on gables or roof slopes. Windows are equipped with louvered grilles for the possibility of adjusting the intensity of ventilation.

Dormer windows are located on opposite roof slopes so that there are no unventilated areas.

Dormer windows can be rectangular, triangular and semicircular. Their lower part should be at a height of no more than 0.8-1.0 m from the floor in the attic, and the upper part should not be lower than 1.75 m from the floor in the attic. They can also serve as an exit to the roof of the house to inspect the roof, ventilation and chimney elements.

Steam and thermal insulation of a cold attic

For a roof with a cold attic, it is most important to minimize heat loss through the attic floor. For both wooden and reinforced concrete floors, vapor barrier is mandatory. It is laid on the ceiling itself and protects the insulation from vapors that can condense in the heat insulator, passing through the ceiling of the living space. As a heater, plate and bulk materials can be used. The ceiling pie consists of a vapor barrier, floor beams and insulation.

The following types of heat insulators are often used in ceiling ceilings:

polystyrene and foam boards;
or mats;
expanded clay granules;
fuel or granulated slag;
sawdust with lime or clay;
pumice.

The thickness of the required insulation layer is selected depending on the calculated winter temperature using the table below.

Winter temperature is calculated according to SNiP 2.01.01-82 (construction climatology and geophysics) or is selected by regions of the Russian Federation from the corresponding climate maps.

Insulation is placed between the joists or beams of the ceiling, and a plank flooring is made on top for attic passages. Logs are usually 50 mm thick, and deck boards are 25-35 mm thick.

For ventilated attic spaces, soft or semi-solid heat-insulating materials are considered the most optimal.

Attic waterproofing device

Waterproofing roofs with a cold attic, according to many experts, is a controversial issue. Some say that waterproofing must be present under the roofing material, and someone categorically recommends abandoning it. Much here depends on the type of roofing material and the angle of inclination of the roof slopes.

Metal roofs are most susceptible to corrosion that occurs with possible small leaks or from condensation. Therefore, once again we draw your attention to the fact that ventilation plays one of the main roles in the fight against condensate.

For flat metal roofs, experts recommend installing superdiffusion membranes. It will prevent moisture from entering the outside of the roof when blowing snow or rain. No matter how well the roof is laid, there is always the possibility of minimal leaks. That is why, having overpaid a little, you will receive additional protection against moisture ingress on the insulation in the ceiling of a cold attic.

Possible leaks or condensate when it gets into hydrophobic heaters significantly reduce their heat-insulating properties.

If, for example, slate is used as a roofing material, then waterproofing can be abandoned. There is also a corrugated board with an anti-condensation coating on the market, which can hold up to 1 liter of water per 1 m 2. For our part, we recommend that you always use waterproofing membranes, because this is the cheapest and easiest additional way to protect your roof from possible leaks.

When installing waterproofing membranes, a counter-lattice is used. It performs the function of a fixing rail and, due to its height, provides the necessary clearance for ventilation of the under-roof space. The device of the crate of a cold attic is no different from insulated roofs. The dimensions of the crate and its pitch determine the type of roofing to be installed.