Substrate for corrugated board on a cold roof. Do I need to lay waterproofing under the profiled sheet on the roof of the shed

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 colossal costs, both financially and in terms of time and effort. Realizing that such a system is in a sense better, many developers asked themselves whether a vapor barrier is needed under a cold roof?

Construction of a cold roof in a residential building

Many developers who want to save some of the money on construction are looking 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 is used 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 thermal insulation material, a vapor barrier layer and other components that are often found on insulated roofs. If you all doubt the savings, then we can say with confidence that the cold version will cost 50-60% less than the insulated structure. In addition, the work can be carried out independently, therefore, the savings will increase even more.

Cold roof cake, in most cases, includes the following products:

Rafter legs
Waterproofing material
Counter battens
Lathing
Profiled metal sheet

Do you need waterproofing under the cold roof metal tiles?

It should be noted that all metal surfaces have one similar feature, they collect condensation. The waterproofing that is part of the cold roof cake will correct this problem and protect the room from the incoming moisture both from the outside and from the inside. When constructing an insulated roof, many developers advise their friends not to install a vapor barrier if they are going to build a building with a cold roof type. They think that the cold will remove the condensation that is visible on metal products, but they are very mistaken.

Condensation occurs due to the temperature difference between the roofing room and the external environment. Naturally, when the attic is not heated and is not insulated by anything, the difference will be small, but still it is sufficient to provoke the release of moisture from the air. As you can see, condensation 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.

As an example, we can cite 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. Most often, a roofing cake consists of rafters, a discharged sheathing and a roof covering. All layers of vapor barrier and waterproofing were simply thrown out. Despite this fact, this building can stand for a significantly long period, and maybe vice versa, fall apart in a couple of years. Here you are already as lucky, but why risk it if you can do everything in a high-quality way?

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

IMPORTANT: If at the beginning of construction you decided to build a cold roof, but later after a certain period you will insulate it, then it is most advisable to lay a micro-perforated film as a waterproofing product. Its properties are practically the same, but according to the price tag, it is much lower than the membranes.

Cold roof waterproofing and ventilation

If you are laying a micro-perforated product, then such a layer will block the access of moisture from the outside, but at the same time water vapor can pass this area without problems. We can say that the installation of vapor barrier products on the roof slopes is optional in this case. After steam penetrates inside, it is between the waterproofing material and the metal cover, from where it is removed by natural ventilation.

IMPORTANT: When a dense waterproofing film is used that traps water vapor, this leads to a significant increase in air humidity and, as a rule, dampness in the room.

With increased air humidity, condensation processes begin, so moisture accumulates on the back of the film and penetrates into all roofing materials. Due to 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 for cold roofs is fairly straightforward. To create it, gaps are left, which, as a rule, are located along the eaves overhang. Air masses pass through them, collect all humidified air and remove it through the cold triangle located in the ridge part of the roof.

The counter grill is a construction 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 cake on both sides, therefore, structures with such a cake last much longer than others.

Cold roof. Do you need waterproofing on outbuildings?

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

Manufacturers from different countries strive to produce such products so that the whole world can start using it. If you are a fan of corrugated board, then today, such material is a sheet of metal with an anti-condensate coating.

In appearance, it practically does not differ from its counterparts. A synthetic compound 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 is saturated with moisture, ventilation comes into play and if it is done according to all the rules and regulations, then the drying process will not take much time.

Thanks to the installation of such a "tricky" 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 these parameters into account and use them in the calculations. It is worth noting that the finished roofing will be much cheaper, because it will not have almost half of the roofing pie.

Installation of waterproofing for cold roofs

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 coatings with an anti-condensate 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 will put on a special outfit, 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, strips of material are placed across the slope, and on strongly sloping slopes along. To improve the quality of laying this layer, the joints are coated with bitumen or glued with double tape.

IMPORTANT: Before installing the lathing, it is very important to treat its elements with special protective solutions, which will increase the degree of fire of the wood and protect it from decay.

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 placed on top of the lattice.
After that, proceed to the installation of corrugated sheets.

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.

Comfortable living in a 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 multilayer roofing cake containing a layer of thermal insulation, heated air does not leave the room in cold weather. Installation of vapor barrier under the corrugated board on the roof helps to maintain low thermal conductivity.

Why do you need a vapor barrier for corrugated board

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

In this case, the vapor barrier layer is equipped to achieve certain goals:

To protect the insulation from moisture vapor penetration. 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 heat-insulating layer and directing water vapor outward.

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. Warm air saturated with vapors rushes to the ceilings, where it cools, and the moisture that appears penetrates the roofing materials.

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

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

Features of the choice of material for vapor barrier

Let's think about what kind of vapor barrier to choose for the roof, so that its efficiency is at the proper level and the cost is affordable. On the building materials market, there is a large assortment 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 you need a vapor barrier for corrugated board, you need to have information on a number of factors:

price;
efficiency of use;
expediency.

Before purchasing materials for profile flooring, you need to deal with the financial side of construction. If price is the determining factor, then economical products are chosen.

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, foil film will be the best purchase, but for a cold roof made of corrugated board, an inexpensive glassine will be enough. When a roof is being erected on a structure that is rarely visited, a vapor barrier made of polypropylene or ordinary plastic wrap will be required.

Vapor barrier products for roofs

To lay a layer of vapor barrier under the corrugated board or other roof covering, 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 traps steam from living quarters. Polyethylene is cheaper than membranes and reinforced films. It has a big drawback - 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. For 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 its 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 reliable protection against moisture, is durable, has a long service life, but, unfortunately, it is heavy. Despite its cheapness, glassine is not recommended for use in residential premises. In case of heating, the material begins to emit an unpleasant odor, and after laying the corrugated board, its temperature rises frequently. For the above reason, glassine is used when the answer to the question of whether waterproofing is needed under the decking of the cold roof of a non-residential attic is positive. It is convenient to use for laying waterproofing on top of the lathing.
Polypropylene film... It is a durable material for vapor barrier laid under profiled sheets. It is produced similarly to a polyethylene multilayer film, but it has a relief layer. Condensation accumulates on films with a smooth surface, then it collects into drops and from time to time they fall on 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, provided that the air humidity drops, the collected condensate evaporates. Mount the film with an anti-condensation surface to the room. For the correct execution of 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 type of polyethylene or polypropylene product. It 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 foil-clad film, heat losses are reduced by more than 10%. The cost of such an insulator is higher compared to other types of vapor barrier materials, but its installation saves on heating costs. It is also necessary to know which side to fix the vapor barrier correctly. Lay the foil film with an aluminum coating towards the room. A gap of about 5 centimeters should be left between it and the wall decoration. 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 is airtight.

Cold roof waterproofing - is it necessary

The space under the cold roof is not heated, but the temperature inside is always different from the outside. For this reason, condensation collects at the bottom of the profiled sheets. Therefore, the answer to the question: "When a cold roof is being built, is waterproofing necessary?" unambiguous. Of course you do. Correctly laid waterproofing on the roof under the corrugated board will exclude the ingress of moisture into the under-roof space.

This layer will prevent wet fumes from getting on the wooden elements of the rafter system and other parts of the roofing structure. The waterproofing is laid on top of the rafters and then secured with a counter-lattice. Next, the crate and the professional sheet are mounted.

When the waterproofing layer does not interfere with the escape of steam to the outside, then there is no need to equip a vapor barrier for a cold roof. Having risen up, water vapors fall through the film under the corrugated board and dry out in that place due to the movement of air currents. 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 you need a vapor barrier for a cold roof? No, since it is equipped only for warm roofs so that moisture does not get into the insulation.

The sheets 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 it can be wood or metal.

Roofing profiled metal sheets are one of the most common roofing materials. The popularity of corrugated board is due to the democratic price, ease of installation, low weight. However, along with the obvious advantages, this material has no less noticeable disadvantages. One of them is increased condensation. Under certain conditions, heavy dew falls on steel sheets, both outside and inside. Because of this, from time to time a little rain literally drizzles under the roof. Wooden structures and insulation have to be protected from condensation. The authors of some articles posted on the Internet argue that a waterproofing layer should be located under the steel sheets and even allow themselves to give advice on the choice of material. However, in fact, waterproofing for corrugated board is not needed, and sometimes it is contraindicated.

It should be understood: by no means all materials designed to protect against moisture are waterproofing.

Waterproofing

It is absolutely waterproof, withstands a fairly large water pressure (continuous flow of water), is very durable and resistant to atmospheric influences, ultraviolet radiation, which allows it to be used in an open state. Waterproofing is suitable for the construction of hydraulic and underground structures, building foundations, flat roofs. Waterproofing materials include bitumen and bitumen-polymer roll insulation, mastics, polymer membranes, special cement-polymer penetrating compounds, bentonite clay slabs.

When installing a flat roof, the waterproofing layer can simultaneously serve as a roof covering

Vapor barrier

As the name suggests, it does not allow water vapor to pass through. Roll waterproofing materials and polymer membranes can cope with this task, but they are inconvenient for use in lightweight wall and roof structures. It is much easier to attach thin and lightweight reinforced polyethylene vapor barrier films to the frame. And they are much cheaper. The vapor barrier is also waterproof and able to protect against rain. But it does not have sufficient mechanical strength and resistance to ultraviolet radiation, which does not allow the use of vapor barrier in an open form, but only under the protection of roofing and wall cladding.

Reinforced polyethylene and polypropylene vapor barrier films are mainly used for roofing. The mounted truss structures in the warm season are allowed to be left uncovered for a couple of months, protected only by a vapor barrier. It will protect the wood from precipitation. But no longer, the resistance of the film to ultraviolet light is limited, it can also not withstand the snow load.

Wind and moisture insulation

Wind and moisture insulation for the roof is able to protect the fiber insulation from being blown by the wind, to a certain extent retains liquid water, but at the same time freely passes water vapor. Due to such selective properties of moisture transmission, wind and moisture insulating films are also called diffusion membranes. They can be made of polymer fibers (non-woven canvas) or perforated film, there are also combined options.

Due to the presence of pores, the diffusion, wind and moisture protection membrane allows water vapor to pass through. But the size of these pores is so small that water droplets falling on the surface do not penetrate the film. Surface tension prevents this from happening. However, if the membrane is wetted for a long time and abundantly, sooner or later it will get wet, "it will leak." Wind and moisture protection is not suitable as protection against heavy rain, immediately after its installation, the roof should be covered with a roof covering

What is a roofing film (membrane)

It is clear: if the film is under-roofing, it means that it is placed directly under the roofing. One of its main functions is to protect the rafter system and insulation (if any) from condensation, which can abundantly fall out on profiled metal sheets. Any of the above insulation materials will cope with it: hydro (steam) insulation, diffusion membrane (wind insulation). However, these are not all the tasks that the roofing film is designed to solve. What exactly is required of it and how to choose the right under-roofing film (membrane) directly depends on the type of roofing. Consider two types of roofs: cold attic and warm attic.

Recently, there has been a tendency to call vapor barrier a roofing film, and wind moisture insulation - a roofing membrane. This is not entirely correct use of the terms, but it just so happened. The main thing is in the difference in the physical properties of these materials.

It is important to know: unfortunately, the Internet is full of confusion on this topic, and ignorant sellers of building materials and illiterate builders also contribute. Often, wind and moisture insulation and vapor barrier are called waterproofing. This is wrong, you need to understand that this is not the same thing, materials have different physical properties, they are designed for different types of roofs.

Roof above the cold attic

There is no need to insulate the attic roof, but you can ventilate it by making holes in the gable walls or filing.

In our case, the fundamental difference between a cold attic and a mansard (combined) roof is how they are ventilated, how excess moisture is removed from wood and insulation

Thus, moisture from the inside of the attic is removed due to good internal ventilation, it is only necessary to protect the structures from condensation that forms on the underside of the roofing. Installation of waterproofing under the corrugated board is possible. Once they did it, they rolled roofing material under corrugated asbestos-cement sheets (slate). Theoretically, you can use old linoleum, sheets of plastic, tin and other unnecessary trash that does not allow water to pass through. However, a special vapor barrier film will last longer, it is easier to fix, it is very inexpensive. You can also use a diffusion membrane, but there is not much sense in this: it will cost more, and its properties of passing water vapor will be unclaimed.

The roof structure of a cold attic should include a vapor barrier film

It is important to know: for a cold attic roof, the best roofing film is a vapor barrier, but any type of moisture-wicking material will do.

Roof over a warm attic

The mansard roof has to be insulated, and the insulation and wooden structures have the ability to absorb moisture from the air. It will not work to ventilate them from below, from the side of the premises, the air there is more humid than outside. On the contrary, from the inside, the roof must be protected from moisture by covering the rafters with a vapor barrier film. The only way to keep the wood and mineral wool from damp is to ensure their ventilation from the outside, making sure to leave a ventilated air gap with a height of at least 4 cm between the roofing and the under-roofing film.Hydro (steam) insulation will not ensure the escape of water vapor, therefore, only vapor-permeable wind and moisture insulation is used for mansard roofs (diffusion membrane).

Correct construction of the attic roof and walls of the frame house. From the inside, the structure should be protected by a vapor barrier, from the outside by wind and moisture protection. But not the other way around!

It is important to know: the only suitable option for a roofing film (membrane) for a standard attic roof structure is a diffusion membrane.

There is a version of the combined (attic) roof, in which a vapor-proof hydro or vapor barrier is used as a roofing film. But in this case, it is necessary to ensure effective ventilation of the space both above and below the film, the total height of the ventilation gaps will reach 10 cm. This solution is effective, but complicates the design and is rarely used. Please note that the underlay (4), closer to the overhang, is brought out over the steel apron (15), and that into the gutter of the gutter system. This should always be done, it is to ensure that condensate flows out of the roof structure.

In conclusion, let us say that not only the comfort of living in the house, but also the durability of the structure depends on how correctly the roof structure is selected and the materials for its installation are chosen. If you do not have sufficient knowledge in the field of construction, do not have the time or desire to delve into the intricacies of modern technologies, the best solution would be to entrust the execution of important work to experienced professionals.

Video: what is waterproofing for

The so-called roofing "pie" consists of many layers. Each owner of a private house decides for himself what should be present in it and what will be a waste of money. For example, roof insulation may not be installed if the room will not be used as. What about waterproofing? Is it worth installing it, especially if the roof is covered with such a reliable material as corrugated board? And if so, how is it done? This will be discussed in the article.

Do you need such an additional layer

Before proceeding to consider the question of how the roof is waterproofed from corrugated board, it is worth understanding whether it is needed at all. If you are going to build a cold roof, in the attic space of which there will be no living space, then the roofing "pie" can be greatly simplified. In this regard, many people have a question, why spend extra money on the installation of waterproofing under the corrugated board.

But this opinion is erroneous. This additional protective layer is still necessary. There are several factors that confirm the need for waterproofing even a cold roof. Let's list the main ones:

Precipitation. No matter how well the roof is made and the profiled sheet is reliably laid, there is no guarantee that in case of heavy rain or snow in combination with wind, moisture will not get under the covering. Water will always find even a small gap through which it can seep.
Wear of attachment points. During operation, the corrugated board is exposed to temperatures and other factors. As a result, the attachment points may loosen. As a result, water will begin to seep under the roof of the house.
Condensation is another reason for waterproofing under the corrugated sheet. Due to the fact that the roof covering is constantly exposed to temperature changes, droplets of moisture can form under it. If water gets on the rafter system, the tree will start to rot and the entire roof structure of your house will quickly fail.

As you can see, it is better that the roof waterproofing is made of corrugated board. Of course, you will have to spend money, time and effort, but with this additional protection, your roof will last much longer. At the same time, minor damage to the covering made of corrugated board will not cause you problems.

What should be the waterproofing

This additional layer is part of the roofing "pie". No matter how reliable the corrugated board is, a lot depends on this multilayer structure. Therefore, special requirements are imposed on waterproofing, namely:

the material selected must be of high density. It is best for this figure to be at least 0.04 kg per square meter. In this case, waterproofing under the corrugated board will be able to withstand high water pressure;
ability to withstand a wide range of temperatures. Waterproofing of a cold roof made of corrugated board should easily tolerate cooling down to -50 degrees and heating up to +100 degrees. The selected material should not change much in size from heating and cooling. Plus, there should be no destruction from frequent (the temperature during the day and at night can be very different) drops;
fire resistance. The corrugated board itself does not burn. This is one of its advantages. But other roof components, such as the rafter system, are made of material that can catch on fire. Therefore, it is advisable to choose a safer material for waterproofing under corrugated board;
another condition is UV resistance. Of course, the corrugated board will cover everything that is under it from the sun. But small gaps may still exist. Therefore, the material chosen for waterproofing the roof from the corrugated board should easily withstand exposure to direct sunlight.

There is also a requirement for vapor permeability. But it mostly refers to the option when a residential attic will be made from the attic space. For the option of a cold roof made of corrugated board, this parameter is not so important. In this case, little water vapor will form in the attic, so the waterproofing layer may not let them through.

What material is better to use

We found out whether waterproofing is needed for a cold roof corrugated board, now it's worth finding out what materials are suitable for this. Modern industry produces a wide range of similar products. It is quite easy to choose an option that will satisfy you both in terms of quality and cost.

Among the most popular materials used for waterproofing roofs made of corrugated board are the following:

If you have enough funds, then it is better to choose the last of the listed options for waterproofing the roof under the profiled sheet. But whatever material you choose, the most important thing is editing. If the waterproofing for the corrugated board is done correctly, then the house will be reliably protected.

How the work is carried out

And how to properly waterproof the roof of a house covered with corrugated board? What are the nuances of this work? Here you should use the advice from experts. The very work on waterproofing for corrugated board is carried out as follows:

the selected material must be stacked on. You can cover from top to bottom (from the ridge to the eaves) and across the roof. Experts recommend using the second option. In this case, the waterproofing will be more reliable. Although the first installation option is much easier to perform;
for any type of installation, the layers of waterproofing are overlapped. It will depend on. The steeper the roof, the less overlap is done. Experts recommend that, with an angle of inclination of more than 30 degrees, the upper layer should go to the lower minimum of 15-20 centimeters. If the roof is flatter, then the overlap is at least 25 centimeters. Another separate recommendation concerns the hip roof option. Here the overlap needs to be increased by five centimeters;
the material itself can be fastened to the crate with staples. Better to choose another option. The waterproofing is fixed with laths and nails. It turns out a counter-lattice. In this case, a small space is formed between the corrugated board and the film. It will serve for the under-roof. This will ensure less condensation on the corrugated board;
all joints between the layers of waterproofing must be repaired. For this, it is convenient to use simple or construction tape;
it is very important to treat the tension of the waterproofing correctly, it should not be there at all. The film or membrane should lie loosely, with a slight sagging of two centimeters. Only in this case will this additional protective layer work effectively;
if a film or membrane is chosen for waterproofing the roof under the corrugated board, then all installation work should be done with caution. These materials can easily tear, which means that the protection will be unreliable.

There is no need to do vapor barrier under a cold roof. In this article, we'll take a closer look at why this isn't necessary.

Why a vapor barrier is not needed for a cold roof

A cold roof is a rafter system on which a waterproofing material is laid. It will prevent moisture from entering the under-roof space and protect the rafter system from premature destruction. Then a counter-grill is mounted to ensure natural ventilation: the air flow enters the roof and removes excess moisture. Usually a bar of 50 * 50 mm is used.

Since there are no significant temperature changes in the roofing "pie", the dew point will be shifted to the insulation of the last floor (warm air will condense in the insulation in front of the attic), therefore no vapor barrier required in a cold roof, but it will be needed in front of the insulation on the last floor, in front of the attic.

Do I need cold roof waterproofing?

Yes, definitely needed... No matter how ideal the roof is, no one is safe from water getting into a microcrack or a minimum gap. From such a gap in the future, there can be big troubles, especially if access to the inner surface is hidden: something is undermining somewhere, and where it is unclear. Waterproofing in such cases is needed, even if there is no insulation.

If the roof is metal, then waterproofing will protect against premature corrosion. Since the thermal conductivity of the metal is higher than that of slate, ondulin or bituminous tiles, condensation will also form more often.

Laying of the waterproofing film is carried out with a slight sagging (about 20-25 mm) so that the condensate flows freely onto the eaves strip, and from it into the gutter. In this case, the supporting structure of the roof will also be protected, and a ventilation gap is provided for effective evaporation of moisture.

Ondutis films for cold roof waterproofing

Waterproofing films Ondutis D (RV) are intended for waterproofing cold roofs.

The film is a gray fabric with the addition of a protective layer and UV stabilizer. This film is used for waterproofing cold or insulated metal-coated roofs. It retains moisture and protects the under-roof space from the harmful effects of condensation and cold air on the inside of the roof.

Ondutis Smart D (RV) is produced with adhesive tape applied to the base, which simplifies installation and reliably insulates joints and overlaps.