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Roof waterproofing under a metal tile - is it needed and which one to choose

Is waterproofing necessary?

To answer the question - do you need a hydrobarrier for the roof, you need to figure out what a metal tile is. Unlike natural, i.e. ceramic tiles, it represents the material.

When installing any sheet covering, gaps form at the joints. As a result, even a large angle of inclination of the slope does not protect the roof from the penetration of moisture into these cracks. The fact is that snow can clog in them, and water can also flow during oblique rain.

But, this is not the only reason why a roofing cake cannot do without a waterproofing layer. As you know, metal has a very high thermal conductivity. For this reason, on the surface of sheets with back side condensation is formed.

Accordingly, if you do not use a hydro-barrier, in the cold season the roof will constantly “drip”. Therefore, we can definitely say that a metal tile without waterproofing cannot be laid.

What waterproofing to use

Currently on the market big choice waterproofing materials. Most often, the following types of modern films are used under metal tiles:

• Reinforced polyethylene;
• Polypropylene;
• Diffuse.

But which of these materials to choose? To answer this question, we will further consider all these coatings, and get acquainted with their features.

Reinforced polyethylene

These films are waterproofing materials, i.e. they do not pass not only water, but also steam ( wet air). Therefore, they are used only for cold roofs. The film is a three-layer material consisting of two layers of polyethylene and a reinforcing mesh in the center.

Advantages. The film has the following positive qualities:

• Tensile strength. This quality is due to the presence of a reinforcing mesh;
• UV resistant. Coating can long time be in the sun;
• Tightness. Roofing film reliably protects the roofing space from moisture.

Flaws. The disadvantages include instability to punctures and other mechanical damage.

Please note that service life and other operational properties largely depends on the quality of the material itself.

Polypropylene

Polypropylene films can be both vapor barrier and waterproof, i.e. able to pass moist air. The latter are used for insulated roofs. Below we consider in more detail the features of the "warm" roofing cake.

As a rule, polypropylene films are single-layer, two-layer and three-layer. The more layers the film has, the stronger, more durable and more reliable it provides protection of the under-roof space from moisture. Of course, three-layer membranes are the most expensive.

Advantages:

• Strength. The coating has good tensile strength and is also puncture resistant;
• Durability. High-quality polypropylene film lasts longer than polyethylene.

Flaws. The disadvantages include less UV resistance.

On sale you can find special anti-condensation films for metal tiles. They have a rough outer surface which traps moisture and allows it to evaporate.

If you choose between polyethylene or polypropylene film, it is impossible to say unequivocally that one of them is better. Therefore, when choosing between any specific models, compare their characteristics.

diffuse

Diffuse membranes are designed exclusively for warm roofs. Their main feature is that they are able to pass moisture in one direction, i.e. out. This property is necessary for the construction of a "warm" roofing cake, which has the following structure:

1. Vapor barrier that prevents the penetration of moisture into the insulation;
2. Thermal insulation;
3. A diffuse membrane that allows moisture to escape, which in any case penetrates into the insulation.

It can be seen from this that the diffuse membrane for warm roof just needed.

Price

I suggest that you familiarize yourself with the cost of all the above coatings. The indicated prices are valid for autumn/winter 2017.

We mount the film

Finally, let's look at how the installation of a waterproofing film is performed. This operation includes several steps:

So, the laying of the hydrobarrier is carried out as follows:

Illustrations	Actions
	Laying the first canvas. Waterproofing usually starts immediately after installation truss system: Roll out the roll and align with the edge of the overhang; Fix the film with a stapler.
	Sealing. Glue the joints of the film with sealing tape or double-sided tape. It is also advisable to glue the areas above the paper clips with sealing tape so that depressurization does not occur in these places.
	Sheathing fastening: To ensure a ventilation gap, be sure to fasten a counter-lattice over the film parallel to the rafter legs; Fasten the battens perpendicular to the battens. As a rule, under the metal tile, the pitch of the boards is 300 mm.

Conclusion

Now you know what kind of waterproofing to choose for a metal tile and how to fix it. If you have any difficulties with the choice or styling, please contact me in the comments, and I will be happy to help you with advice.

Waterproofing under the metal tile is a mandatory layer that protects the attic from condensation. And if we take into account that the joints of the roof elements do not differ in tightness, then this is also an additional impermeable barrier to leaks. It is only important to choose the right materials and scheme for a particular type of roof ...

Roofing materials that protect the building from the action of precipitation from the outside cannot fully ensure the “dry” mode of operation of the attic. Especially when it comes to metal roof. And the reason is condensation. Therefore, waterproofing under a metal tile is an obligatory layer of a roofing pie. But what should be the waterproofing of the roof under the metal tile, which one to choose and how it is laid, our article will tell.

Such waterproofing of the roof will provide reliable protection even when leaking roofing material

Causes of condensation and its negative consequences

Daily temperature fluctuations outside and a relatively constant temperature inside lead to the fact that even in summer a rather large difference in the partial pressure of water vapor in the air inside the house and outside its walls is created. Of course, when air conditioners work in the heat, this is not so. But the rest of the time, warm, moist air will tend to go outside, and according to the laws of physics, the main direction is the ceiling and roof. If there is no absolute vapor barrier in its path, then it will reach the cold metal of the roof and the moisture from it will condense.

Note! Someone calculated that as a result of life, one person “evaporates” up to 4 liters of water per day (sweating, hygiene, wet cleaning, washing, cooking). And there may be pets in the house and houseplants which also evaporate moisture.

"Dry" air in a residential area is generally contraindicated. And during the heating period, its humidity is raised specially

But besides the influence of humidity interior spaces, there is still atmospheric moisture, which, together with the outside air, penetrates into the under-roof space. Therefore, even with reliable vapor barrier, it is impossible to completely prevent the conditions for the appearance of condensate. And this is bad for both an insulated roof and an uninsulated one.

What is bad condensate for the roof and attic

The condensate has a harmful effect, first of all, not on the steel of the metal tile. And although the "wet mode" is not the best for ferrous metal, it is reliably protected by a layer of zinc and paintwork.

Moisture can penetrate through such protection to the metal only if the layers are mechanically damaged.

Therefore, the assertion that waterproofing under a metal tile prevents early metal corrosion is not justified (it would be logical to “wrap” the entire roof in plastic wrap). In addition, mandatory ventilation of the under-roof space vents excess moisture, and the metal is not in constant contact with water.

Condensation is harmful to rafters, mauerlat and other wooden load-bearing elements roofs, as well as for insulation (in a cold attic - lying on the floor, in a warmed one - as part of a roofing pie). And dampness in the attic is bad in any case, especially if an attic is equipped there.

Note! Waterproofing under the metal tile also serves as an additional waterproof layer in case of penetration of rain or melt water through leaky joints of the roofing material in overlaps and junctions with other surfaces.

Such seals under the metal tile are placed only on the ridge and cornice. The impermeability to precipitation of the joints between the sheets is ensured by overlapping

On our website you can find contacts construction companies who offer . You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

How is the waterproofing of a metal roof

The device for waterproofing the roof under the metal tile has a standard scheme. Although there are certain differences depending on the type of waterproofing materials and methods for draining condensate outside the roof.

The waterproofing of the metal tile is designed so that the condensate formed on the surface of the metal, when it enters the waterproofing material, should roll down to the roof eaves. Therefore there is a few prerequisites for any scheme:

styling roll waterproofing run along the rafters, and lead it from the bottom up, with an overlap of panels of at least 150 mm;

waterproofing carpet should be continuous layer;

overlap size adjacent vertical panels should be at least 150 mm, and the overlap joint should fall on the rafter leg;

all joints must be glued self-adhesive tape from the same material as the waterproofing;

bottom edge of the canvas on the cornice they are attached with self-adhesive tape to a metal dropper ( cornice plank), from which condensate flows either outside the roof onto the blind area (with an unorganized drain), or into the gutter;

Roof waterproofing with organized drain"ends" at the gutter

stuffed on the rafters distance bar with a section height of at least 50 mm - it provides a ventilation gap between the waterproofing and the roof (it is then attached step crate for the installation of metal tiles);

to avoid the penetration of condensate in the places where the distance bar is attached to the rafters, under it install sealing tape;

along the perimeter of the entire layer, as well as at junctions with other surfaces waterproofing is glued adhesive tape.

Metal roof waterproofing materials

Water tightness is not the only requirement for waterproofing materials under metal roofing. In order to normally transfer the installation process along the rafters, they must have good strength to mechanical stress.

For non-insulated pitched roofs, it is possible to use materials with limited vapor permeability. And for insulated roofs, it is recommended to use materials with high vapor transmission characteristics - at least 1000 g / m 2 per day.

The last condition is necessary to create a normal humidity regime for the insulation. Waterproof but "breathable" materials are called membranes (with high performance– superdiffusion membranes).

This is how the structure of a two-layer membrane looks like - impermeable to water and permeable to steam

Note! There are schemes of insulated roofs in which vapor-proof materials are used as roof waterproofing. But these schemes have a more complex device.

Membranes can be either single-layer or multi-layer. For the most part, they have stable vapor permeability characteristics, but they can also have a variable vapor resistance value.

Modern hydro- and vapor barrier materials for inclined metal roofs are made of polymer woven or nonwoven fabric. This is due to both operating conditions and installation technology. And in reality, this is such a waterproofing for a roof under a metal tile which is better today.

About roofing material

The statement about the possibility of using roofing material (or bituminous and polymer-bitumen roll materials similar in composition) for waterproofing metal tiles is incorrect.

Regardless of the reinforcing material of the base and the composition of the binder, all types of bituminous roll materials are practically impervious to steam. And this limits the scope. They are used as a vapor-tight layer under the insulation on floors made of reinforced concrete slabs or roofing sheeting in flat roofs.

Lining roofing felt on pitched roof can be attached to a discharged crate, but with a small step between the boards. To the rafters, like a membrane of polymer materials, it is not fixed

On pitched roofs, bitumen and polymer bitumen roll materials they are used only on a continuous crate of OSB3, OSB4 boards or moisture-resistant plywood, the vapor permeability of which is almost the same. BUT solid crate used for "soft" roofing materials - the same roofing material or shingles.

You can, of course, make your own discharged crate for the roofing material flooring, and fasten it with nails, but these are laying patterns for other roofing materials. Moreover, in such cases it is necessary to use a board, to do the crate with a small laying step, and this will come out more expensive than even with a multilayer membrane.

And as the last argument against the roofing material - the company TechnoNikol in both of its systems pitched roof with LUXARD composite tiles (similar to metal, but with surface layer from stone chips) uses a three-layer superdiffusion membrane made of polypropylene as a waterproofing layer. Moreover, it is indicated in the diagram as a classic cold roof, and the attic. Although the company's product catalog contains a large assortment waterproofing rolled bituminous materials.

This is what it looks like standard scheme pitched non-insulated roof from the TechnoNikol Company

Features of installing waterproofing for different types of roofs

The general principles for waterproofing the roof of a house under a metal tile have been described above. They apply to both the cold attic and the attic. The differences are only in the vapor-permeable characteristics of the materials. But not everything is clear here - each manufacturer indicates its own schemes.

Video description

How to carry out the installation of roof waterproofing and lathing under the metal tile in the following video:

Uninsulated roof

The TechnoNIKOL company does not distinguish between the nature of the operation of the attic, and everywhere indicates a superdiffusion membrane as a waterproofing layer.

Another equally reputable domestic manufacturer of Gex (he owns trademark Izospan) allows the use vapor barrier materials to create a layer of waterproofing under the metal tile of a cold roof. There is no fundamental contradiction in the schemes, since cold roof ventilation has two circuits:

roof space- in the ventilation gap eaves overhang metal tiles to the ridge;

truss system- from holes in the eaves of the attic for air flow to the "break" of the waterproofing film under the roof ridge.

The second circuit just provides weathering excess moisture from the attic, including from the floor insulation. And already the insulation must be covered with a superdiffusion membrane.

Video description

Another option for waterproofing, see the following video:

insulated roof

For waterproofing the insulation and the truss system, TechnoNikol in its scheme indicates a superdiffusion membrane. The difference from an uninsulated roof is that it is laid with a gap up to the rafter leg - for this, another 2.5 cm high counter-lattice bar is attached to the rafters. roof space. And the vapor barrier is used for its intended purpose - they are attached to the crate in front of the insulation, when viewed from the side of the heated room.

The installation of an insulated roof using Izospan materials has two options:

No gap between insulation and waterproofing. In this case, a superdiffusion membrane is used, which is attached directly to the rafter legs without additional counter-lattice beam. There is only one gap between the waterproofing and the metal tile, which is responsible for both removing water vapor from the insulation and for weathering moisture from condensate.

A typical scheme of an insulated roof with a metal tile, in which the waterproofing is attached to the rafters without an additional spacer

with gap. The Geksa company indicates this option as optimal for attics. covered with metal tiles. For waterproofing, Izospan DM is used, which is listed in the catalog as a vapor barrier. high strength. This scheme has two bars of the counter-lattice: the first is for the gap between the insulation and the film, the second is for the gap between the film and the metal tile. And both gaps have their own “zone of responsibility”: the first is for weathering water vapor from the insulation, the second is for condensate evaporation.

The presence of a second ventilated gap worsens the thermal insulation of the roof

Conclusion

According to the device, the abundance of schemes, the range of materials and the number of technologies, the roof is perhaps the most hard part at home. Of course, she does not have such a responsible "role" as the foundation. But correcting errors and repairing is a costly undertaking, and the leakage of the roof will entail restoration. interior decoration at home. And it is better when professionals are involved in the design and installation of the roof.

All developers are wondering what to put under the metal tile in order to save on long years wooden elements roof structures, and the roof itself. The durability of the rafters and longitudinal beams, the air temperature in summer and winter in the attic directly depend on the choice of the substrate for the tiles. First of all, you must follow all the recommendations of the tile manufacturer.

Of the metal tile, it includes several insulating layers, which have an important function in protecting the entire house from negative impact cold, moisture, noise.

What role does the substrate play in the operation of the house, what types of substrate are there and in what cases is one or the other used? Let's try to sort out these issues.

Substrate varieties

The substrate for the metal tile must be selected depending on the purpose of the attic space.

There are substrates for cold rooms and there is a substrate for residential, that is, heated premises. There are certain requirements for substrates for residential premises (such as an attic), and others for a cold attic.

Underlayment for a cold attic is much simpler than for a heated attic. A counter-lattice is attached to the rafters, and a crate is attached to it. Leave between them free space for air circulation.

A film is placed on the crate to protect wooden structures from moisture that penetrates into attic space through leaks in the tiles.

For warm attic the design of the substrate looks different. The crate and the counter-crate are also attached. But more stringent requirements are imposed on waterproofing. In this case, it should not only protect the attic from moisture from the outside, but also from the condensate that forms on inner surface metal tiles due to the temperature difference between the outside air and the inside.

On top of this, the waterproofing film must ensure the removal of water vapor rising from the lower rooms so that the insulation remains dry and does not lose its qualities.

Between waterproofing and insulation leave air space 2 to 4 cm for air ventilation.

Depending on the climate in your area, choose the insulation material and its thickness. Below lay the film for insulation. And already on top of the film sheathe the living space at the request of the developer. This design is called a "roofing pie". It is optimal for protection roof structure from external and internal adverse conditions.

Substrate from roofing material

It is laid on only if there is a crate and only with a cold roof.

Roofing material as a substrate is used only for cold attic spaces. To put or not to put roofing material under the metal tile, each developer decides for himself. It should only be noted that if the roof is cold and the attic is well ventilated, then roofing material can be laid, but in this case it is necessary to provide an air cavity between the roofing material and the tiles.

If the roof is old and already covered with roofing material, then in this case it is possible on top of it, having previously mounted a crate for the air gap.

But most experts are skeptical about such a device and believe that it is best not to put the roofing material under the metal tile, because, in the end, this will lead to damage to the roof.

Roof waterproofing

The waterproofing layer protects thermal insulation material and the entire wooden structure of the roof from the effects of rain and snow, which get inside when strong wind. In addition, the film prevents the ingress of condensate from inside tiles for thermal insulation.
can be done in two ways:

1. Mount the crate on the thermal insulation and put a film on it, thereby providing a gap between them of 2-4 cm for ventilation.
2. And you can put the film directly on the thermal insulation without a gap. But at the same time, it is necessary to use a special membrane-diffuser. Such a film will not let moisture in from the outside and at the same time absorb that which rises from the lower rooms in the form of wet vapors.

And although the membrane-diffuser film has a higher cost compared to ordinary film, it has undoubted advantages. It is placed directly on the insulation, and there is no need for an air gap. In strong winds, it significantly reduces heat loss.

Being waterproof from the outside, the film is able to absorb vapors from the inside, that is, such a roof will “breathe”. As a result wooden structures roofs will stay dry and last much longer.

Warming and vapor barrier

The thickness of the insulation depends on climatic conditions region and reaches 20 cm.

Depending on the climatic conditions in your area, thermal insulation under the metal tile choose a thickness of 15 to 20 cm.

The heater is made from mineral wool. It is produced in rolls or pressed plates.

The insulation is cut 10 mm wider than the distance between the rafters. During laying, it is inserted into place and, starting from the middle, is gradually pressed in, trying to avoid wrinkling and deformation. In this case, the insulation must fit snugly against the rafters, the joints must be sealed.

To protect the insulation from moisture that rises from the lower rooms in the form of vapors, you need to put the last layer of the so-called roofing pie. This layer is made up of polyethylene film, reinforced mesh. It must be laid with an overlap of 10 cm, starting from the bottom.

To finishing material did not touch the film, the strips are attached to it and the trim is already attached to them.

Ventilation under the roof

The waterproofing film / membrane protects against moisture from the outside, the vapor barrier - from internal moisture. The installation of such double-circuit insulation provides an upper and lower air outlet/inlet.

Ventilation must be provided under the roof. This is due to several reasons:

1. Ventilation removes moisture from under the roof. Moisture leads to corrosion metal structures and to the destruction of concrete and brick parts.
2. Ventilation equalizes the temperature under the entire roof and thus prevents the formation of frost, as it damages the roof and the drainage system.
3. AT summer time the temperature in the attic decreases.

Ventilation air enters through the eaves lining and exits through the ventilated roof ridge. If the ridge does not provide for an air outlet, that is, a “deaf ridge”, then in this case roofing valves are installed.

They are used both on cold and insulated roofs under metal tiles. There are also valves that can be installed on the roof ridge.

Roofing errors

Typical mistakes that must be avoided when building a "roofing pie":

1. Under no circumstances should you put vapor barrier film instead of waterproofing. In this case, the moisture that has entered the insulation will remain in it;
2. Also, you can not put a film for waterproofing instead of a vapor barrier. In this case, the roof will not "breathe".
3. Do not lay the membrane-diffuser film backwards. And in this case, moisture will get into the insulation and stay there.
4. Be sure to observe the number of all ventilation gaps in the "roofing pie". Since the metal tile is very afraid of the appearance of moisture on its back side.
5. Don't skimp on roofing. It has long been known that the miser pays twice. By purchasing cheap low-quality goods, in the future it will turn into expensive repairs for you.

It is much easier to do well right away than to fix it later.

If you arrange the roof according to all the rules, then it will serve you for many years, keep your house warm in bad winter weather and give coolness in the summer heat.

Metal tile is a convenient, reliable, lightweight, aesthetically attractive material widely used in roofing. In cottage construction, a metal roof is a kind of de facto standard.

An important role in terms of durability and reliability of the roof device will play waterproofing. During its installation, specially designed films are used, and the installation itself is carried out according to a special technology that provides a high-quality roof hydrobarrier.

Roof waterproofing made of metal tiles is a component of long-term operation of the roof

The construction market has a large number of various roofing materials and some developers are sure that with right choice and quality installation roofing, it is quite possible to do without waterproofing. A similar opinion exists regarding the metal-tiled roof. However, it is not.

A roof made of metal tiles has many gaps through which atmospheric precipitation (snow, rain) penetrates. Over time, under the influence of strong gusts of wind, the weight of the snow cover, the flow of rainwater, the tightness of the metal tile is broken. In addition, the roof covering is constantly exposed to water vapor leaving the interior of the facility.

To avoid negative consequences when arranging a metal-tiled roof, it is necessary to include a layer of waterproofing in the "roof pie". It's in equally applies to both "cold" roofs and insulated ones.

Thus, the waterproofing of the roof under the metal tile performs the following tasks:

• prevents the penetration of moisture from the outside;
• prevents the accumulation of condensate on the roofing;
• improves the thermal insulation of the entire room.

Metal roofs are durable and reliable. The main thing during their installation is to observe the technology of laying the "roofing pie" and adhere to the principle of optional tightness.

A little water may enter small intertile gaps, but high-quality waterproofing should divert this water and prevent its accumulation. Thanks to small gaps in the coating and micro-perforation of the hydro-barrier, ventilation of the supporting wooden crate is ensured (its service life is extended) and the internal and external air pressure is equalized, which prevents the roof from falling off during strong winds.

Materials for waterproofing metal roofing

quality waterproofing requirements

Parameters of high-quality waterproofing of a metal roof:

• fire resistance;
• high vapor permeability;
• endurance, strength, reliability;
• resistance to temperature fluctuations sun rays and other atmospheric influences;
• the ability to resist deformation and retain properties under mechanical loads and changes in natural factors;
• effective removal of moisture from the under-roof space;
• environmental safety for human health (do not contain or emit harmful substances into the atmosphere);
• resistance to pests, mold and rot.

The service life of the waterproofing layer must correspond to the service life of the metal tile coating, otherwise after some time it will be necessary to repair the roof

If the waterproofing is not replaced in time, then structural elements roofs (sheathing, insulation, beams and supports) will gradually begin to deform and rot. The indoor climate will worsen, and the roof will no longer be reliable.

types and characteristics of waterproofing materials

The range of materials for waterproofing and roofing, and walls, and the floor of the premises is very diverse. They differ in thickness, resistance to UV rays, color and other characteristics.

Used for waterproofing metal roofs roofing film- a three-layer material having a braided (bearing) reinforcing lattice, which is laminated on both sides with a polyethylene film. The film acts as a hydro-barrier and has vapor permeability.

Bitumen-based waterproofing materials and mastics are not recommended for waterproofing under metal tiles.

There are several types of waterproofing film:

As a waterproofing layer for a "cold" roof, roofing material can be used, but at the same time, an air gap must be left between the layer of metal tiles and roofing material

It is necessary to store the hydro-barrier film in places inaccessible to UV rays. For the arrangement of a metal-tiled roof, it is necessary to use a low-combustible type of waterproofing (has the designation "special"). Such material prevents the spread of fire in case of fire and does not form combustible droplets that can become additional source ignition.

Installation of waterproofing under metal roofing

basic rules for waterproofing a metal roof

Work on waterproofing the roof of metal tiles must be carried out, adhering to the following rules:

sequence of waterproofing works

When waterproofing a metal roof, special attention is paid to preparatory work which include:

1. Construction of the truss system. Calculation roof structure must be made at the design stage of building a house.
2. Install the cornice board and frontal board. This is necessary to give strength and rigidity to the structure.
3. Mount the gutter hooks for the gutter system.

Preparatory measures require literacy and professionalism from the contractor, since the quality of their implementation affects not only the waterproofing of the roof, but also the stability and reliability of the entire building

For the installation of waterproofing, it is necessary to prepare the following tools and materials:

• scissors for cutting waterproofing film;
• roulette;
• marker;
• long wooden slats;
• a hammer;
• construction stapler;
• screwdriver;
• metal staples.

Consider the sequence of installation of waterproofing under the metal tile:

features of waterproofing cold roofs

When arranging a cold sloping roof made of metal tiles, the presence of an attic space is necessarily provided. The attic must be equipped with a ventilation grill or a window through which moisture vapor will escape.

In this case, roofing felt, a vapor-tight film or a superdiffusion membrane can be used as waterproofing.

When installing a highly permeable membrane, ventilation windows and grilles can be left in the attic - this will help retain additional heat and protect the attic from rain, snow and street dust. The attic of the house will remain dry and clean. Wasps, birds and insects will not be able to penetrate into it, and the window can be glazed.

Waterproofing of metal roofing - important aspect when building a house, which should not be neglected. High-quality and competent waterproofing of the roof will improve the thermal insulation of the room and extend the life of the roof.

The cold roof structure includes a waterproofing layer, as well as a batten, a load-bearing frame, a counter batten and a roof deck.

When installing a cold roof, a ventilation gap is provided between the waterproofing and the roofing material.

The gap provides active air circulation in the under-roof space, contributes to the effective evaporation of moisture from the surface of the waterproofing and prevents corrosion. metal roofing.

Why is it necessary to install waterproofing under an uninsulated metal roof?

Condensation protection

The waterproofing layer primarily serves to protect the metal roof from condensation that appears from the interior due to the difference in temperature inside and outside the house.

In the absence of waterproofing, condensate will accumulate on the inner surface of the metal roof and gradually destroy it. This, in turn, will lead to leaks and shorten the life of both the roofing material and the supporting roof frame.

Protection against atmospheric precipitation and leaks

For all the seeming strength of the metal tile, it has "weak links": the points of attachment of the flooring to the crate and the overlaps of the modules.

With heavy rainfall and gusty wind, moisture can penetrate into the under-roof space along the junction line of metal-tile sheets, and in case of weakening of the fastening of the hardware and deformation of the sealing elements, through the mounting holes.

Converting an attic into a residential attic

If in the future you have a desire to re-equip non-residential attic into a dwelling, then with the existing waterproofing layer, the process of arranging a roofing pie will be greatly facilitated.

What is suitable for waterproofing a cold metal roof

When choosing a hydrobarrier for a metal roof, you should not save too much - overhaul roofs in case of corrosion of the flooring and deformation of the truss system will cost much more. Therefore, cheaper polyethylene and polypropylene films it is better to prefer more efficient superdiffusion and anti-condensation membranes.

For waterproofing under cold roof suitable film