Installation of cold roofs. Cold roof made of metal tiles. Vapor barrier under corrugated sheets or metal tiles

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

Installation of a cold roof made of corrugated sheets

The installation of a cold roof is advisable, first of all, for economic reasons. Firstly, you save on materials, and secondly, by isolating a large area of ​​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.

This article is devoted to how to properly make a cold roof from corrugated sheeting.

Installation of a cold roof made of corrugated sheets in a residential building

The design of a cold roof is very simple. The slopes do not require any insulation, vapor barrier, or, moreover, finishing. Naturally, the savings in this case are quite 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 cold roof made of corrugated sheets can be installed with your own hands without any problems.

The cold roof pie consists of the following elements:

1. rafters;
2. waterproofing film or membrane;
3. counter-lattice;
4. sheathing;
5. corrugated sheeting

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 condensation is released on metal surfaces when there is a temperature difference, there is a common misconception that it will not occur if an uninsulated roof made of corrugated sheets is installed.

Naturally, such an opinion is not true, since, despite the fact that the under-roof room is not insulated or 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 sheeting if the roof is cold?” - unequivocal: “Yes, it will be.”

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

Installation of waterproofing film with sagging

The waterproofing membrane of the cold roof is laid on the rafters and secured with a counter-lattice, after which the lathing for installing the corrugated sheeting is installed.

If you do not intend to insulate a cold roof in the future, then you can use microperforated film as waterproofing, which costs much less than special membranes. However, it must be installed 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 ventilation of cold roofs

Since microperforated films prevent the penetration of moisture from the outside, but do not interfere with the passage of water vapor, a vapor barrier for a cold attic on the roof slopes is not required. Water vapor, having passed through the film, ends up between the waterproofing layer and the corrugated sheet, from where it is removed by an air flow.

If a 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, as humidity increases, steam will condense on the film from the inside. Therefore, ordinary polyethylene and polypropylene films, as well as outdated materials such as roofing felt or glassine, are not suitable for waterproofing cold roofs.

Ventilation of a cold roof is very simple and is achieved by creating a gap using a counter-lattice: the air flow enters under the roofing through the eaves and exits through the ridge.

Always make a counter-lattice

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

Ventilation of a cold attic is carried out using ordinary dormer windows, which must be located in such a way as to ensure the passage of air flow when ventilated throughout the room. If the size of the under-roof space is large, the ventilation of a cold attic in a private house can be improved using a classic supply and exhaust circuit.

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

If a cold roof made of corrugated sheets 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 insulation cannot be installed 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 ideal for these purposes. They, of course, are more expensive, but their use will reduce the thickness of the roofing pie by 80-90 mm. If you already use microperforated film as waterproofing for a cold roof made of corrugated sheets, you must provide a gap of at least 50 mm between its lowest point, taking into account sagging, and thermal insulation.

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

Cold roof made of corrugated sheets in utility rooms

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

Corrugated sheeting coated on the inside with an anti-condensation coating

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

Thanks to the use of corrugated sheets with anti-condensation coating, the design of a cold roof becomes much simpler and cheaper, since neither waterproofing nor counter-lattice is needed. In addition, such material is indispensable for gazebos, verandas, canopies and other open structures, since they generally do not use waterproofing, and condensation appears no worse than in a cold attic.

Installation of cold roofing from corrugated sheets

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

Then the house is sheathed. About how to make it and what step to choose depending on the brand of profiled sheet -.

Next, the direct installation of a cold roof made of corrugated sheets 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 any 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. Read more about installing a cold roof made of corrugated sheets.

Don't forget to treat the rafter system

Cold roofing technology is quite simple, so its installation is quite quick. However, all wooden components of the roof must be treated in advance with special compounds that will prevent them from rotting, as well as mold and mildew.

How to insulate a cold roof?

Often, installing a cold attic is just an intermediate stage. Most cold roofs are insulated over time in order to increase the living space of the home. This is easy to do, since there is no need to redo the cold roof pie - it is, in fact, the upper part 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, rather than a micro-perforated film, as waterproofing, then the thermal insulation material is laid closely between the rafters. Then the internal lathing is made with bars of the required thickness, between which a second layer of insulation is mounted. They can also be used for finishing with wooden boards or drywall.

Insulating a cold attic using sprayed polyurethane foam

When insulating a cold attic, a layer of vapor barrier 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 compounds that prevent rotting.

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

In addition, insulating a cold roof made of corrugated sheets using polyurethane foam allows you to create a continuous layer of thermal insulation, in which not only will there be no cracks, but the rafters will also be covered. The only drawback of this method is the cost. Also, you will not be able to do this work yourself, since it requires expensive equipment.

No roofing material is perfect. Even in its main quality - protection from moisture. And in cases where the roof is covered impeccably, and there are no leaks during rain or melting snow, condensation still remains on the inside of the roof.

To protect the rafter system and the attic of a cold roof from condensation, waterproofing is installed as part of the roofing pie. And the fact that it also protects against “small” leaks is a bonus in the form of a time reserve to eliminate roof leaks.

In what cases is waterproofing needed for a cold roof?

There are not that many roofing materials available. If we consider only, the list will be reduced to several species. And depending on the characteristics of the material itself, the installation technology and the purpose of the building, waterproofing is not always necessary.

Metal roofing

Metal roofing can be sheet or piece. Sheet materials are,. Piece covering - roofing checker and roofing scales.

Regardless of the size of the element and the laying technology, the “layering” is the same for everyone:

• rafters;
• waterproofing;
• counter-lattice to ensure the required ventilation gap;
• sheathing;
• roof.

The presence of waterproofing and a ventilation gap in the under-roof space is mandatory both for heated houses for year-round use and for unheated cottages or outbuildings.

Any roofing metal has high thermal conductivity and low heat capacity. As the temperature drops daily, the roof cools much faster than the air inside the attic. And it will appear almost every day, even in summer.

In winter, if the building is heated, the air in the attic will be even warmer - any thermal insulation of the ceiling is not absolute. Just like any vapor barrier, it does not provide complete protection against the penetration of warm air vapor into the attic from the room. And there are also chimneys and ventilation ducts, which also serve as a source of heat.

Waterproofing protects the attic and rafter system. And to prevent the counter-lattice and sheathing from getting wet, there must be a ventilation gap in the under-roof space.

Slate and ondulin

Although these materials are different in composition, the likelihood of condensation appearing on their surface is low.

Slate is best in this regard. Its surface texture can be compared to an anti-condensation waterproofing film. A rough surface can retain condensation until conditions for its evaporation and weathering occur. Therefore, waterproofing is not needed for a cold slate roof.

As an example, we can cite Soviet-built apartment buildings - in most “Khrushchev” buildings, slate is laid over lathing without waterproofing. And the only reason the attic gets wet is roof leaks.

Ondulin has almost the same properties. On the manufacturer’s website, as one of the “economy” options for installing a cold roof, a laying diagram without waterproofing is given. And this option is suitable for country houses and summer cottages, summer kitchens and outbuildings.

For permanent residences, roofing made of slate and ondulin without waterproofing is considered not reliable enough. And here it is recommended to lay waterproofing roll materials. standard - the film is attached to the rafters with a slight sag, counter-lattice beams are stuffed on top and.

Roof tiles

There are several types of roofing material where this term is present:

Bituminous shingles. Waterproofing is provided at the level of installation technology from the manufacturer. This is one that also serves as an additional fixing element. The bitumen contained in shingles and carpet bakes together when the roof heats up from the sun.

Composite tiles. This is a kind of metal tile with a small sheet size. The differences lie in the composition of the protective and decorative layer. As with any metal roof, waterproofing must be installed underneath it.

Ceramic and cement-sand tiles. They differ from each other in composition, shape, manufacturing technology. But despite this, installation proceeds according to general principles. And the manufacturers of these types of roofing also stipulate the presence of waterproofing when describing them.

What waterproofing materials can be used

There are three types of modern materials:

Superdiffusion membranes. They have good waterproofing properties and high vapor permeability. They are rarely used in cold roofs due to their high cost and excessive “breathing” properties. The main purpose is to protect the insulated roof. It is installed on non-insulated roofs if there are plans for further insulation and the attic is in use.

Diffusion membranes. Good waterproofing properties and average vapor permeability. The optimal choice for slate, ondulin, ceramic and cement-sand tiles.

Water vapor barrier films with anti-condensation surface. This is a universal material that is characterized by high waterproofing properties and limited vapor permeability. Such materials can also be used as a vapor barrier.
Recommended as . They block most of the water vapor in the warm air, which is then ventilated through the eaves and ridge vents of the attic ventilation and through the dormer window.

How to lay film correctly

The waterproofing film is mounted from bottom to top with an overlap of panels of at least 15 cm. The fastening is carried out to the rafters. The film should sag between the rafters, but no more than 2 cm. Additionally, a sealing tape is glued on top, and then a counter-lattice block is nailed.

If it is necessary to increase the length of the canvas, then the joint should be on the rafter leg. Extensions are also done with an overlap of 15 cm.

The superdiffusion film is laid on the ridge without tearing. When installing other types of waterproofing materials in the ridge area, it is necessary to leave a “gap” of about 5 cm on each side.

Is it possible to use roofing felt?

Sometimes roofing felt and its analogues are used as waterproofing for pitched roofs. But these materials are intended for waterproofing flat roofs over a continuous floor.

The technological map of the TechnoNikol company for the installation of bitumen roll materials indicates that the roofing material is attached to the base using mastics or by fusing.

Mechanical fasteners at large roof slope angles are used as additional “point” fixation to prevent bitumen waterproofing from slipping in hot weather. And this limits the scope of use of roofing felt on pitched roofs.

On those roofs where the slope angles are large and the technology for laying the roof is continuous, lathing is not needed, it is not economically profitable to install it, even though roofing felt is cheaper than waterproofing films. But only mechanical fastening along a row sheathing does not provide sufficient reliability of fixation due to the low tensile strength of roofing material.

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 this arrangement of the attic space, a sufficiently large buffer air zone is formed, which allows you to effectively regulate the temperature in the attic if it is properly arranged.

Cold attic design

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

Cold attic roofs have the following main components in their pie::

1. roofing;
2. attic external walls (applicable for gable roofs with gables);
3. insulated ceiling between the living space and the attic.

Ventilation is provided by eaves and ridge vents. The air passing through the eaves openings is called supply air, and the air leaving through the ridge is called exhaust air. Additionally, ventilation can be done through dormer windows on the gables or roof slopes. The windows are equipped with louvered grilles to allow the ventilation intensity to be adjusted.

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

Dormer windows can be rectangular, triangular and semicircular in shape. Their lower part should be at a height of no more than 0.8-1.0 m from the floor of 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, a vapor barrier is mandatory. It is laid on the ceiling itself and protects the insulation from vapors that can condense in the heat insulator after passing through the ceiling of the living room. Slab and bulk materials can be used as insulation. The ceiling pie consists of a vapor barrier, floor beams and insulation.

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

• expanded 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 estimated winter temperature using the table below.

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

The insulation is laid between the joists or ceiling beams, and a boardwalk is made on top for the attic passages. Joists are usually 50 mm thick, and decking 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, while others categorically recommend that it be abandoned. Here, a lot depends on the type of roofing material and the angle of inclination of the roof slopes.

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

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

Possible leaks or condensation entering hydrophobic insulation materials significantly reduce their thermal insulation properties.

If, for example, slate is used as a roofing material, then waterproofing can be abandoned. There is also corrugated sheeting with an anti-condensation coating on the market, which can hold up to 1 liter of water per 1 m2. For our part, we recommend always using 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 serves as a fixing strip and, due to its height, provides the necessary clearance for ventilation of the under-roof space. The installation of lathing in a cold attic is no different from insulated roofs. The dimensions of the sheathing and its pitch determine the type of roofing being installed.

At the moment, in the process of constructing a country residential building, different options for high-quality modern structures for the roofing part of a building or structure can be used. A relatively simple one among them is the cold roof. Such a device is optimally suited in cases where the common attic space is not used as a residential space for some reason.

The design scheme of such a plan is characterized by simplicity; there are elements such as high-quality waterproofing, load-bearing elements and roofing. There are some installation features of this design. They consist in the fact that it is imperative to provide a high-quality ventilation gap designed to remove accumulated condensate.

This is necessary so that the load-bearing structural elements, as well as the roofing itself, are effectively protected from the adverse effects of moisture.

The installation of such a roof itself is not characterized by any difficulties. The most important thing that needs to be done is to properly fasten all the profiled metal sheets present.

This must be done so that precipitation cannot penetrate through the numerous joints under its surface. Before starting the construction process, it is worth carrying out such important steps as:

• Make all necessary calculations;
• It is imperative to calculate the parameters of the angle of inclination of the roof structure;
• It is important to determine the pitch of the sheathing;
• You also need to decide on the method of fastening sheets of roofing material.

Compliance with these rules will allow the construction process to be completed quickly and efficiently.

The one described differs from the warm roof in its relative simplicity. The only thing that must be taken into account is the special type of roofing material and its flooring.

When using modern metal tiles, it is recommended to provide an effective ventilation gap that will properly remove condensation from the room located under the roof. This is necessary so that the steel element is not subject to corrosive destructive processes.

The device of this design is the installation of a rafter system; a membrane or high-quality film is mounted on it. Then the counter-lattice, sheathing, as well as the covering, that is, metal tiles, are secured.

The main features of this design include the complete absence of a heat-insulating layer; there are also special ventilation holes, they are located strictly under the ridge and on all slopes without exception.

These devices are used for efficient removal of water. The process of professional design and subsequent installation will not present any difficulties for the master; the most important thing is to correctly carry out all the calculations.

The process of high-quality and professional installation itself consists of such features as:

1. If you are planning a device, you will need to competently select a high-quality protective membrane for effective protection from excess moisture. For an attic room, only special high-quality waterproofing can be suitable, which can take the form of an ordinary membrane, which is usually made from PVC.
2. If you do not need to use the room in the future, you can use special micro-perforated waterproofing. It is needed specifically for this design, like a cold roof. Such material does not make it possible to lay different thermal insulation in the immediate vicinity; any further insulation will require spending money on the purchase of new material.

Important! If such conditions are not met, the roof will not be protected from moisture after some time. In this case, the insulation will always be wet, and the roofing material will be severely damaged by destructive corrosion.

For the installation process of a high-quality waterproofing membrane, it is necessary to remember that it can be installed with a certain sag of approximately 20 mm. This factor makes it possible to arrange the drainage of drops, which effectively protects rafters and other structural elements of the roof from excess moisture.

In order for water to be eliminated as efficiently as possible and not to stagnate, thereby creating a relatively unfavorable environment, it is imperative to provide a high-quality ventilation hole. It is carried out between the film and the roofing ridge.

Such a gap makes it possible to circulate under the roof without problems, and all traces of moisture and condensation will also be effectively removed.

Important! During the work, it is very important to ensure that the protective membrane does not have ruptures or any other defects, and it is fastened using a special construction stapler. It is mandatory to overlap, that is, all edges of the film must be secured using tape.

Of all the main features inherent in a cold roof, it is worth noting that it is possible to build it, if necessary, for any region of the country. Many people assume that this type of coating may not be suitable for some regions, but in reality this is far from the case.

For a standard living space, having a cold, unheated attic is a traditional solution in all respects.

It is worth noting that the use of a roof of this type will not affect the temperature of the upper floors. The attic space itself may not be used at all, and heat loss is solved by installing a layer of high-quality insulation between the upper floor and a special under-roof space.

In the process of constructing a cold roof, it is worth remembering such a stage of the work as proper insulation of all existing technological exits and openings. These are such structural elements as:

• Chimneys;
• Special mines;
• Entrances leading to the roof surface.

All of them require special thermal insulation. High-quality work will allow you to quickly avoid such unpleasant moments as the appearance of large amounts of condensation, icing, heat loss and the penetration of precipitation.

A device of such a design as a cold roof is one of the most common options due to its simplicity. The roofing pie contains the following layers:

• On the side of the rooms there is a layer of high-quality waterproofing, which has one-sided permeability;
• Roof truss system;
• Film from moisture, necessarily sagging a little;
• Counter-lattice, the construction of which is carried out strictly parallel to the previously installed rafters. Wooden boards of this system firmly press the waterproofing, that is, they provide another high-quality fastening;
• The sheathing of this cold roof design is made from high-quality timber made of wood. Its cross-section should be 50 by 50 mm. It is installed in a certain step, approximately 40 cm, but it is directly based on the category of metal tiles used;
• The topmost layer is the metal tile itself.

1. A film is secured to the rafters using a special stapler or small galvanized nails, which provides waterproofing.
2. Then it is pressed with fastening devices.
3. The step directly depends on the category of metal tiles used.
4. The size of such boards should be on average 25 by 95 mm.
5. Sometimes professional builders use a continuous-structure coating made from sheets of high-quality plywood.

The film, which provides effective protective waterproofing, must be laid with sagging, but other defects are strictly unacceptable. The degree of sagging of the roof covering should be approximately 15-25 mm. This will provide an opportunity to guarantee the highest quality ventilation, as condensate will be removed.

The moisture will first go into the strip on the eaves, and then into the gutter. Neglecting this process will result in moisture completely destroying the roof.

When building a cold roof made of metal tiles, you must remember that a sheet of this material does not provide protection from noise. That’s why no one lives in the attic; it’s cool and noisy there.

To install a cold roof, you need to take relatively simple tools, as well as consumables that can be purchased relatively inexpensively. Special staples are used as the necessary fastening devices; these can be self-tapping screws or galvanized nails.

Important! In the process of calculating sheets of roofing material, you need to remember that you will definitely need additional elements such as valleys, ridge tiles, cornices, and so on.

The design of a standard cold roof differs from an insulated structure precisely in the absence of an insulation layer. Such a roof is erected if the attic will not be used as a living space.

Read in the article

Material characteristics

Metal tiles are a roofing covering based on galvanized steel with a polymer or paint layer, used for the construction of cold or warm roofs. It is produced by cold rolling from steel billets. The strengths of metal tiles are:

• A light weight. One square meter of metal tiles weighs 5.5-6.5 kg, which makes it possible to install them on thin lathing without reinforcing the roof rafter frame.
• Long service life. High-quality metal tiles, as well as additional elements made of galvanized steel, can be used for more than 20-25 years with proper maintenance and timely repairs.
• Corrosion resistance. The zinc layer and polymer coating reliably protect the steel from exposure to water, so the metal tiles are not subject to corrosion.
• High load-bearing capacity. Thanks to the wavy profile, metal tiles have high load-bearing capacity and do not deform under intense loads.
• Resistant to temperature changes. Temperature changes do not affect the strength properties and integrity of the material, so it is used in all climatic zones.

Important! It is recommended to lay metal profile coverings on single-pitched and multi-pitched roofs with a slope of at least 12 degrees. To install a cold roof, you will need the roofing material itself, as well as additional elements: valleys, ridges, eaves or gable strips, drainage elements, soffits for filing eaves, lightning protection, snow retainers

The design of a warm roof involves the additional use of insulation and vapor barrier.

Structure of a metal tile sheet

Possible sizes of metal tile sheets

Ventilation

The relative complexity of the metal tile roof design requires additional measures to ensure sufficient ventilation of the internal spaces of the roof.

Ventilation patterns differ when using cold and warm types of roofing.

The air exits through the holes located in the roof ridge. With this scheme, it is possible to stop air exchange when an ice crust forms in the internal space due to a temperature difference, which makes it not the most reliable method of ventilation.

A cold roof makes it possible to build a more extensive and reliable ventilation system. With this scheme, pipes are constructed that pass through the roof and exit into the attic. Dormer windows are constructed on the roof slopes. The installation of such ventilation is relatively expensive, but the reliability of this system is at a high level.

IMPORTANT!
In a warm roof, no additional bulky structures are constructed; air circulation is ensured by creating gaps between the insulation and metal tiles, as well as by the correct location of the sheathing.

The main mistakes when installing a roofing pie under metal tiles

1. Carrying out measurements and calculating the required materials must be entrusted to experienced specialists. Otherwise, mistakes may result in additional costs for purchasing missing items or unnecessary costs for extra materials.
2. When unloading, metal tiles must not be dragged along the ground. When handling the material in this way, the inner layers of the polymer coating are damaged, which subsequently leads to corrosion of the metal.
3. Metal tile sheets cannot be saved, since increasing the length creates additional joints. In the future, they will become a potential source of depressurization of the roofing pie and moisture getting inside.
4. Metal tile sheets should not be bent too much. This negatively affects the topography of the roofing. During installation, the joints of the sheets will be uneven. The resulting gaps will allow moisture to penetrate. Visually, these defects are very noticeable, which greatly spoils the appearance of the entire roof.
5. The service life of the external coating will be significantly reduced if it is installed without a counter-lattice.
6. During the construction of the roof, it is necessary to level the sheathing. An uneven base leads to deformation of metal tile sheets, the formation of gaps at the joints and a decrease in the service life of the material.
7. Under no circumstances should you use a grinder to cut sheets of metal tiles. The abrasive wheel burns through the polymer coating, and hot particles falling on the surface of the material spoil it. The same mistake is made by those who use a grinding machine with an abrasive wheel. Cutting metal tiles with this tool leads to the fact that not only the polymer coating deteriorates, but also the zinc layers are burned through. Subsequently, rusty stains form in these places.
8. If mineral wool slabs are deformed or crushed during the installation process, it will reduce its thickness and lose its thermal insulation properties.
9. The joints of sheets of metal tiles, the places where the material connects to chimneys, as well as the junction with windows cannot be filled with polyurethane foam. Such a mistake speaks more about negligence than the builder’s ignorance of his business. Polyurethane foam is sensitive to ultraviolet radiation, when exposed to which it crumbles.
10. Installation of a metal roof pie is a responsible process, so it is necessary to select qualified builders to attract it.

Video: how not to fasten metal tiles

Compliance with construction technology, selection of high-quality materials and the involvement of experienced specialists will allow us to produce high-quality roofing for metal tiles. These conditions will guarantee the durability and strength of the constructed structure.

Materials used

We found out that waterproofing is the most important element of a roof covered with metal tiles. But what should a high-quality water-protecting layer be like? The requirements for waterproofing are as follows:

• it must have increased fire resistance;
• good steam flow;
• strength and reliability indicators must be high;
• the material should not deteriorate due to sudden temperature changes and should not be afraid of ultraviolet radiation;
• the layer must withstand a certain level of mechanical loads;
• waterproofing should not be susceptible to pest attack or mold development;
• it must also cope well with its main tasks and not cause harm to human health.

Laying waterproofing material

Various types of materials can be used for waterproofing. They all have a lot of differences from each other, including different resistance to light, strength, quality and durability.

In most cases, special roofing films having several layers are used for waterproofing metal tile roofs. There is a reinforcing and absorbent layer. The first provides protection from precipitation, and the second is able to absorb moisture coming from the inside, so that condensation cannot accumulate on the waterproofing and mold will not form. Also, on both sides the material usually has a polyethylene lamination.

Roofing films

This coating has special pores that allow the passage of vapors that form inside the house, but at the same time do not allow moisture coming from outside to spoil the materials from which the roof is made. This feature of the material, called vapor permeability, is especially important if the attic space is converted into an attic and is used as a living space.

Exiting vapor and waterproofing on the roof, screwing in metal tiles

Advice! When choosing a material for waterproofing, it is important to pay attention to its service life. It should coincide with the service life of the metal tiles, so that you do not have to dismantle the roof and lay waterproofing again if it fails, and the main roofing material will still be usable

The service life of the special film used under metal tiles is 50 years.

Name	Short description
Standard or classic	A film with low vapor permeability, for which it is important to equip the so-called double-circuit ventilation, which will be located between the roofing and waterproofing materials, as well as between the film and the insulating layer of the roof. The gaps between them should be 3-5 cm. The material is ideal for constructing a cold roof or a roof with a simple structure.
Anti-condensation	A material that also requires the creation of dual-circuit ventilation. The film is equipped with a moisture-absorbing fleecy layer that perfectly retains excess water. This is a fairly dense material, rough to the touch, durable and resistant to ultraviolet radiation. But the vapor permeability of such a film is low.
Superdiffusive	The best material for roof waterproofing, as it has increased vapor barrier performance and does not require dual-circuit ventilation. It is enough to leave gaps between the film itself and the roofing. Installation of this film is simple, it has a long service life. The main disadvantage is the high price.

Isover Tyvek Solid roofing film

On a note! Hydrobarriers made from bitumen and bitumen mastic, which are widespread and still in use today, should not be used for arranging a metal tile roof.

Of course, for temporary roofing you can use cheaper film, but for capital construction it is better to take high-quality, albeit expensive, material. There is no need to save money here and it is better to buy a diffusion membrane coating. All indicators of the purchased film are shown on the edge tape that frames the material. The film is produced in rolls 1.5 m wide and 50 m long. The density of the material is about 140 g/m2. A prominent representative of the optimal material for laying under metal tiles is Izospan AM or AS.

Izospan AM

Izospan AS

Insulation of a metal tile roof with foam plastic

Scheme of insulating a metal tile roof with foam plastic.

Foam plastic has become quite widespread as insulation under metal tiles. In addition to the low price, it has the following properties:

• due to the lightness of the material, insulation does not require additional strengthening of the load-bearing roof structures;
• the insulation is very easy to install, it can be processed with any tools;
• polystyrene foam is environmentally friendly and does not cause allergies;
• resistant to biological substances, therefore not susceptible to mold or bacterial growth;
• good resistance to moisture and temperature changes;
• insulation using polystyrene foam will last a long time;
• the insulation has good soundproofing properties;
• the foam structure of the foam provides low thermal conductivity, which allows it to retain heat perfectly;
• low price.

Foam can be used to insulate roofs of any type, but it is best suited for flat roofs. Insulating complex pitched roofs using polystyrene foam requires good skills, since during installation you need to try to avoid the formation of cold bridges - seams and joints. In some cases, it can be difficult to achieve this result due to the rigidity of the foam. In this case, there is a possibility that condensation may accumulate in the resulting voids, resulting in the destruction of the roof rafters or corrosion of the metal parts of the roof frame.

Insulation of the roofs of residential buildings should be carried out only using special foam plastic, which does not emit harmful fumes when heated and is a fireproof, self-extinguishing material. When determining the thickness of the foam, it is necessary to take into account the thickness of the rafters. If the thermal insulation material is laid in 2 layers, it may be greater than the thickness of the rafters, which will lead to the need to build them up for subsequent finishing.

When choosing foam plastic for metal tiles, it is necessary to take into account its density, which is the main indicator of the ability to withstand loads. For example, for pitched roofs it is better to use a material with a density of 15 kg/m3 and a thickness of 100 mm, and for flat roofs in use - PSB-35 foam plastic.

Calculation of the amount of metal tiles

To calculate the required number of sheets of material, you first need to decide on the type of profile and the manufacturer of the metal tile - you will need the exact dimensions of the material itself, and each profile has its own. Then you need to make accurate measurements of the slopes - length, height, if any, you need to measure all the protrusions or other decorative elements that will need to be sheathed with roofing material. If the roof has a complex shape, it is better to draw a plan, put down all the dimensions and then start doing the calculations.

Number of rows

It is best to look for metal tiles not in stores or markets. It is advisable to contact the manufacturer directly. The point is not only in the price - it may not differ very much, but in the fact that many workshops/factories offer to cut sheets of the required sizes. The minimum sheet height is 0.7 m, the maximum is 8 m. That is, you can order the required number of sheets covering the roof slope from the ridge to the overhang (taking into account the eaves overhang).

This option is good because a metal tile roof will not have horizontal joints, which means there will be less chance of leaks. The second plus is the minimum amount of waste and a smaller amount of the material itself (due to the absence of horizontal overlaps, several square meters are saved). Disadvantages - difficulties with delivery, lifting long sheets to the top, inconvenient installation.

Calculation of a rectangular roof slope

When using sheets of standard sizes, the height of the roof slope is divided by the useful length of the sheet. The resulting figure is always rounded up. The useful length is obtained after subtracting the amount of horizontal overlap from the total length - from 100 to 200 mm. The flatter the slope, the greater the overlap of the sheets is necessary so that precipitation cannot get into the under-roof space. On roofs with a slope of up to 12°, one sheet overlaps the other by at least 200 mm, with a slope of 12° to 30° the overlap is 150-200 mm, more than 30° - 100-150 mm. The specified amount of overlap is subtracted from the total length of the sheet, this will be the “useful length”.

An example of calculating the number of rows of metal tiles on a roof. Let the length of the slope be 4.5 m, the useful length of the sheet is 2.3 m. Divide 4.5 by 2.3, we get 1.95, round to the nearest whole number - we get 2 rows. In this case, only a small part of one sheet will go to waste, but there are times when more than half is cut off. This is very unprofitable, since this piece cannot be used anywhere else.

Number of sheets in a row

Take the length of the slope and divide it by the usable width of the sheet. This parameter is indicated in the technical specifications for metal tiles. Most often it is 110 cm (1.1 m). We round the resulting number up to obtain the number of sheets in the row.

An example of calculating metal tile sheets in a row. Let the length of the overhang be 8 m, the useful width of the sheet 1.1 m. When dividing, we get 7.27 pieces, but round up to a larger integer and we get 8 pieces in one row. Moreover, more than 2/3 of one sheet will go to waste.

Features of hip roofs

Hip roofs have slopes that are triangular or trapezoidal. Here it is necessary to select the length of the sheet in order to minimize the amount of waste.

An example of the layout of metal tile sheets on a hip roof

The height is selected so that no more than half goes to waste. It is quite difficult to do this manually, and there is still a significant error - there will be 20-25% more waste than when calculated using programs. They are usually available from sellers and manufacturers. It is better to provide them with an accurate calculation, and first measure the parameters of the roof at home (or call a measurer), and then try to select the dimensions yourself. Then you can compare the amount of material needed, calculated by you and proposed.

Determining the number of additional elements

A metal tile roof requires a large number of different additional elements (additions), which form the ridge, the edge of the overhang, the sides of the slope, the passage of the pipe, the valley (the junction of two adjacent roof slopes). The more complex the shape of the roof, the greater the amount of additions required. With a simple gable roof, ridge elements and caps, cornice and pediment strips will be needed. That's all.

What types of additional elements are there for metal roofing and why are they needed?

Despite the wide variety of extras, they are all considered the same. Take the length of the surface on which it needs to be mounted and divide by the useful length of the element. It is usually standard and is 1.9 m (total length 2 m). The result obtained is rounded up.

Proper arrangement of ventilation

Regarding this point, metal roofing is simply unique of its kind. Despite all the efforts to make the coating airtight and protect the roofing pie as much as possible from precipitation, there are many difficulties when working with this material. This is all due to the unusual shape of the metal tile, which allows snow and raindrops to gradually fly under the covering.

And this is already bad for insulation, and for any insulation. Therefore, proper ventilation is needed here, which will immediately bring out such random snowflakes or drops. That is why, when insulating a metal tile roof, the only correct option is forced ventilation. Believe me, natural will not be enough.

Additionally, be sure to use a guide. The flow guide is used in eaves overhangs. Its main purpose is to direct and remove air from the thermal insulation material, thereby protecting it from possible snow blowing during a snowstorm. On the other hand, the flow guide prevents loose mineral wool from scattering along the eaves or roof ventilation ducts.

This unusual product is made from impregnated moisture-resistant cardboard. Izover air guides for the rafters are designed in steps of 90 or 120 cm, but if desired, you can handle non-standard steps

Pay attention to the photo of this step-by-step instruction for insulating a metal tile roof - the pink unusual detail is the flow guide:

Metal tile top layer of roofing

Just as the roof itself is a definite completion of the structure, so a material such as metal tiles is the upper part of the roofing pie.

Important! Competent professional installation of high-quality metal tiles, which have high quality characteristics, is a guarantee of the most efficient operation of the roofing covering. This material is able to serve for a huge number of years without loss of quality; the roof will please every home owner for a long time.
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Modern professional manufacturers of this material guarantee that the total service life of metal tiles, subject to compliance with all installation and application standards, can reach 50 years. This attracts a large number of developers and also determines their choice.

An important element that is responsible for the quality and practicality of the roofing cake, which is directly responsible for the tightness of an element such as a roof, is an element such as a seal. It is installed on special ridges, to such elements as wind, valley and special wall strips.

Important! It is required to carry out the most thorough inspection of the entire roof surface approximately twice a year for preventive purposes.

Particular attention must be paid to all additional elements present, structural joints and any connections.
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Important! All materials used must be high-quality calibrated and very well dried, strictly in natural conditions. Before installing the lathing or counter-lattice, it is best to treat the materials used with special antiseptics and substances such as fire retardants.

Diagram of a metal tile roof.

A single-pitched unloaded roof can be insulated with slabs of increased rigidity. For a gable roof, in some cases, insulation with materials of low density, but with a foil-coated one-sided surface, is allowed. It is especially convenient to use such products in the thermal insulation of the attic. The roof is covered from the inside so that the foil is on top - the heat will be reflected and partially returned to the room.

A properly insulated roof is a multi-layer structure:

• protective film;
• thermal insulating material;
• waterproof membrane;
• lathing made of wooden slats;
• layer of metal tiles.

After 5-6 years, new insulation will be needed, which will entail extra costs. Therefore, you should remember: following the technology will help you avoid mistakes when insulating the roof and save a lot of time and effort, and correctly selected materials will ensure warmth in the premises for many years. Metal roofing is the best solution for your home! The next article will tell you how to insulate ventilation on a metal roof.

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Creating a ventilation space

Ventilation under the roof– a mandatory element, since it serves several purposes at once:

• removes moisture accumulating under the roof;
• prevents the formation of icy areas and equalizes the temperature over the entire surface in winter;
• prevents the penetration of street heat in hot weather.

A special ventilated roof ridge is designed to remove air, and the air flow occurs through the overhang of the eaves. Without properly installing the ventilation system, you will soon encounter the problem of high humidity, and as a result, the structure will quickly begin to deteriorate.

Metal tiles on roofing felt

A common type of substrate for metal tiles is roofing felt. This material can be used for an uninsulated attic..

This scheme has a lot of advantages:

• roofing felt – inexpensive substrate, which will significantly save your repair costs;
• installation of the substrate does not require special skills;
• roofing felt – popular building material, so you can buy it everywhere.

However, for high-quality installation of metal tiles on roofing felt, you need follow certain rules:

• Under no circumstances should sheets be laid directly on roofing material; this creates favorable conditions for the structure to shift. It is necessary to make the sheathing in two layers: 1 - along the roofing felt, 2 - under the wave of metal tiles;
• as an alternative, you can fill ordinary slats along the installed rafters;
• To prevent fire and simplify ventilation of the room, it is worth constructing ventilation holes.

Roofing installation is best left to professionals. However, if you are determined to carry out all the work yourself, then carry it out in accordance with the established requirements. Only in this case can you obtain a durable and reliable design.

Pitched roofs

Advice. A pitched roof can be insulated from the inside when steam and waterproofing has already been installed. It is better to carry out insulation with your own hands while the roof is being built.

Pitched roofs are, as a rule, a load-bearing frame system, which includes rafters, Mauerlat, ridge, sheathing, struts and other elements. The load-bearing parts of the system are usually made of metal profiles or wood. In such a multilayer structure, a layer of thermal insulation is placed inside the supporting frame. Glass wool and lightweight mineral wool slabs are best suited for insulating pitched roofs.

Installation procedure and features

Before covering the roof with metal tiles with your own hands, you need to familiarize yourself with the rules for working with the material:

• First of all, you need to take care of proper storage - in ventilated stacks, arranged with bars.
• When cutting, do not use an angle grinder (grinder), but cut only with a jigsaw or metal scissors. The grinder overheats the metal, which causes the zinc to evaporate, and the material will begin to rust at the cut points.
• Start laying the sheets from the lower right corner (the installation diagram for metal tile sheets is in the photo below).
• When installing, wear soft, well-fitting shoes and step only on the lower part of the wave.

How to cover a roof with metal tiles: rules

Next we will talk about the device. Metal roofing comes in two versions: with a cold or insulated attic. Depending on the type chosen, the order of work changes - when arranging a warm attic, two more layers are added - insulation and a vapor barrier membrane on the room side.

Cold metal roofing

This type of roofing is suitable if the attic space is planned to be non-residential. Then all the insulation is concentrated in the ceiling, and the function of the roof is only to protect from precipitation and wind. The order of work is as follows:

• The first sheathing strip (higher) is installed along the overhang.
• The drip strip is attached to it.

A waterproofing membrane is spread over the rafters. Installation begins from the bottom, the film is rolled out along the overhang. The lower edge of the film extends onto the drip bar, ending after the inflection line. The film is attached with strips 30-35 mm thick to each rafter leg, not in a stretched manner, but with a mandatory sagging of 2-2.5 cm. The second row of film overlaps the first by at least 15 cm, the joint is glued with a special adhesive tape (sold in the same place where and membrane). The membrane is attached to the drip strip with self-tapping screws (galvanized or stainless steel).

Cold roofing made of metal tiles: layer density

• Sheathing boards (bars) are attached to the strips that hold the film at the selected pitch. Use galvanized or stainless steel screws, the same type of nails with a large flat head. The length of the screws and nails is three times the thickness of the sheathing strips.
• Sheets of metal tiles are laid on the sheathing, aligning them strictly along the overhang (if it definitely runs horizontally). Adjacent sheets overlap by one wave, installation is carried out from bottom to top, with obligatory horizontal overlap by the required amount (see above).
• Mount ridge elements and end strips. They are fastened with the same screws as metal tiles, in increments of 10 cm.

Warm roof

When installing an insulated roof made of metal tiles, a thermal insulation material is added to the roofing pie, which is attached between the rafters, and a vapor barrier film, which is placed on the rafters from the attic side. Further, the entire installation process is similar.

Diagram of a warm roof made of metal tiles

How to attach sheets

When we cover a roof with metal tiles, we need to position the screws correctly. There are several rules that must be followed:

• Self-tapping screws are installed in the lower part of the wave, 2 cm below the step.
• The bottom row, along the overhang, is attached to each wave. Fasteners are also installed in places of horizontal and vertical joints.
• The waves between the horizontal joints are attached through one in a checkerboard pattern.

These rules are clearly shown in the diagram. In a graphical representation, some things are easier to understand.

Scheme of fastening metal tiles with self-tapping screws

Cold or warm roof

There are two types of roofing using this material, which differ in their characteristics. Cold roofing does not use insulation; it is suitable for cases where insulation can be laid in the attic floor. Warm roofing is done in cases where the living space is located directly under the roof.

Cold roof.

Two layers of materials are used - waterproofing (to protect the interior from possible condensation) and metal tiles. Both layers are separated from each other by counter-lattice and sheathing, and ventilation is provided at the junction of the slopes. For waterproofing, PVC or a thick film is used; the material should not be fully tensioned; the film should sag by about 25 mm, which improves moisture drainage. The waterproofing layer is attached to the rafters and fixed under the sheathing.

Used in houses where the attic will not be used as a living space

Warm roof.

The basis of this type of construction is insulation, which additionally performs the function of sound insulation. For this, various types of insulation can be used. The thickness of the insulation depends on the characteristics of the building and the climate of the region, generally its layer is at least 15 cm. Another important indicator of insulation is fire resistance. Thermal insulation is located in the space between the rafters; a vapor barrier layer is used below the thermal insulation and waterproofing. Small gaps are made between the layers to ensure ventilation. All layers at the same time must be sufficiently dense (so that there are no voids where moisture accumulates) and not thick (so as not to interfere with ventilation).

This scheme is used to arrange a warm room under the roof.

When purchasing materials, it is necessary to maintain the cross-section of the boards so that repairs will not be necessary in the near future. To equip the roof, metal roof tiles, additional elements, boards, screws and other consumables are purchased. The price of the structure will depend on the type of coating chosen, insulation, size and shape of the roof. The average cost of one meter of roof is 1-1.5 thousand rubles. Counting the amount of materials should be left to qualified craftsmen.

The shape of the roof plays an important role in determining the price
On our website you can find contacts of construction companies that offer the service. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

The issue of waterproofing and ventilation

The metal has high thermal conductivity. This means that in the warm season it will heat up like a frying pan, and freeze in winter. You can somehow cope with high temperatures in summer. And in winter, a cold roof will consume a lot of heat, which can lead to large bills for heating the house. Due to temperature changes, already in the fall, when it is cold at night and still warm during the day, a huge amount of condensation forms. Smudges form that flow under the coating and threaten the thermal insulation material. Even if the roof is insulated, the thermal insulation material may become wet, causing it to cease to perform its functions over time.

Therefore, the main point in installing a warm roof made of metal tiles is the creation of a waterproofing barrier that will protect the heat insulator from leaks from the inside of the metal covering.

The hydrobarrier is a special reinforced membrane that covers the roof slopes. Its function is to protect the thermal insulation material from accidental leakage of water from rain and snow and from condensation, which is an integral companion of a metal roof.

It is not enough to simply protect the thermal insulation layer from leaks. It is necessary to ensure that the roof structure is provided with good forced ventilation, due to which all condensate will be ventilated outside.

Waterproofing device using polypropylene film

An alternative option for waterproofing a warm roof covered with metal tiles can be a two-layer waterproofing polypropylene membrane. On the one hand, such a coating has a layer of non-woven material that absorbs condensation. On the other hand, there is a hydrobarrier with ventilation pores, through which drops of formed water will come out. Such a membrane is laid with the first layer inside, where the thermal insulation is located, and with a hydrobarrier - to the outer layers of the roof.

Double-layer polypropylene film designed specifically for roof waterproofing

Super diffuse coating

The superdiffuse membrane is one of the latest developments in the field of waterproofing and building materials in general. Its properties resemble leather, and the development of such a coating came from the textile light industry - membrane materials have been used in sportswear since the middle of the last century.

They differ from conventional polypropylene films in the number of layers - in a superdiffuse membrane there are up to four of them! All layers have pores in their structure through which drops of condensate are discharged. Multilayering ensures the membrane's tensile strength. The last outer layer of the coating has an ultraviolet filter.

Superdiffuse membranes - the last word in roof waterproofing

Superdiffuse coatings are available in roll and mastic form. The second type is also called “self-leveling roofing”. It is considered more economical compared to rolls, but loses in vapor barrier properties. And, due to its consistency, its use is allowed only on horizontal surfaces. An additional complexity is created by the surface coating technology - the layer of mastic must be uniform, and this task is difficult for even professionals to cope with. Therefore, in private construction they use a roll modification more - you can handle its installation yourself.

The advantage of a super-diffuse coating is that it can be used as temporary roof protection before installing metal tile sheets on an insulated roof. This greatly facilitates the construction of a roof with other coverings, as is the case with soft tiles.

Selection of material for insulation

Thermal insulation materials for metal roofing are quite varied, but the most popular are polystyrene foam, polyurethane foam and mineral wool. These insulation materials are light in weight, which means that the pressure on the floors will be minimal. In addition, they are environmentally friendly, easy to use and last a very long time, provided that the thermal insulation is laid in compliance with the technology. If a metal roof is insulated somehow, even the most modern and expensive materials will not help.

It is worth considering that the thickness of the roof’s thermal insulation layer should not be less than 15 cm and exceed 25 cm.

Metal tile diagram.

Most often, mineral wool slabs are chosen as insulation for metal tiles. Cotton wool in rolls is also suitable, but it is not so convenient to lay, so slabs can be called an ideal option.

As practice shows, insulation of a smaller thickness will not provide good thermal insulation, and a layer that is too thick will put extra pressure on the ceilings, and the roof will become less reliable. To correctly calculate the required volume of material, you need to multiply the total roof area by 0.2.

Types of substrates

The substrate for metal tiles should 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 rooms. Substrates for residential premises (such as an attic) are subject to certain requirements, while those for a cold attic are subject to different requirements.

The underlay for a cold attic is much simpler than for a heated attic. The counter-lattice is attached to the rafters, and the sheathing is attached to it. Free space is left between them for air circulation.

A film is placed on the sheathing to protect wooden structures from moisture, which penetrates into the attic through leaks in the tiles.

For a warm attic, the design of the substrate looks different. The sheathing and counter-lattice 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 condensation that forms on the inner surface of the metal tile due to the difference in temperature between the outside air and the inside.

Functional diagram of a roofing pie for a warm metal roof.

To top it off, 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.

An air space of 2 to 4 cm is left between the waterproofing and the insulation for air ventilation.

Depending on the climate in your region, choose the insulation material and its thickness. An insulating film is placed below. And the living space is sheathed on top of the film at the request of the developer. This design is called a “roofing pie”. It is optimal for protecting the roof structure from external and internal adverse conditions.

Roofing pie structure for metal tiles, including waterproofing

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

The film or membrane for waterproofing the attic is laid freely, with some sagging. However, it is worth making sure that the integrity of the coating is not compromised, 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 inside of the waterproofing membrane is achieved, and condensed moisture is removed onto the eaves strip and further into the drain. Neglecting such a simple rule will ultimately provoke premature deformation of the roof frame and the entire roof.

The peculiarity of a metal roof is that cold roofing film is not able to reduce the noise level that occurs when intense rain falls on the metal. Therefore, residential premises 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:

• A vapor barrier for a cold roof is laid from inside the room, which only releases moisture to the outside and prevents it from penetrating into the living rooms.
• Next, install the rafter frame for the roof.
• The next layer is a waterproofing material. The film is laid with sagging to drain condensate.
• Next, a counter-lattice is attached, which presses the waterproofing, securing it, and provides ventilation gaps.
• Then the sheathing is stuffed to secure the roofing. It is made from slats 50x50 mm and laid along the slopes with an indentation of 35-45 cm. Based on the type of roofing and the slope of the slopes, the pitch of the sheathing and the thickness of the board for it may vary.
• The last thing to do is lay the metal tiles.

Pie of roof insulation made of metal tiles without counter-lattice

The lathing, attached to the frame of the rafter system without a counter-latt, tightly presses the elements of the roofing pie, leaving no gaps for ventilation of the structure. In this case, only horizontal openings remain between the sheathing beams. This is not enough, since warm air and steam will rise, and tightly pressed structural elements will hinder this process. As a result, all evaporated moisture will settle on the wooden elements of the frame, and if the vapor barrier layer is damaged, inside the insulation. This will lead to the fact that the wood will begin to rot after the first winter, and the insulation will become unusable.

The counter-lattice creates the required distance between the rafter system and the roofing pie, which allows ventilation of the entire frame. In this case, the water will not linger and settle on the structural elements, but will go out together with the flow of warm air.

Even if all the layers of the roofing pie are already installed on the rafter frame without a counter-lattice, the situation can be saved. To do this, wooden blocks with a cross-section of 20x40 cm must be secured to the inside of the rafters parallel to their edge. A vapor barrier membrane must be secured on top using a stapler. In this case, the necessary distance for ventilation is formed between the vapor barrier and the insulation.

If there is no ventilation gap in the roofing pie, the moisture does not evaporate, but settles on wooden structures and insulation

Roof thermal insulation

For high-quality thermal insulation of the roof of a structure such as an attic or the living part of an attic, the following modern finishing materials should be used:

• Special basalt materials as insulation;
• High-quality semi-rigid insulation, which belongs to the semi-rigid category;
• Mineral high-quality insulation;
• Ecowool;
• High-quality glass wool;
• High-quality extruded synthetic polystyrene foam.

All such materials that provide thermal insulation are characterized by a low degree of thermal conductivity, but are leaders in the construction of roof insulation. This is based on a large number of defined indicators.

How to make waterproofing

When insulating a roof covered with metal tiles, be sure to install a water barrier. This is a special reinforced, vapor-permeable film that protects the attic space from condensation, dust and accidental rain or snow.

Pay special attention to the first problem - it is on metal tiles and corrugated sheets as a metal material that condensation quickly accumulates. After all, metal always heats up quickly and cools down just as quickly, creating a significant temperature difference between the object and the air - ideal conditions for the settling of water vapor in the form of droplets

When steam condensation reaches a critical point - the dew point - water molecules in the air bind and turn into water. The main conditions for this are high indoor humidity and temperature differences. Plus a poorly designed vapor barrier, of course. And thanks to the micro-perforation of modern water vapor barriers, a small ventilation will be created, which will help such droplets evaporate faster. A good budget option.

Polypropylene films with an anti-condensation layer are also suitable for solving this problem. One side of such barriers is made of non-woven geotextile, and the other is waterproofing. The textile insert of such a film adsorbs moisture and steam and removes them through the ventilation gaps. What’s good is that such a film can be left on the roof without a roofing covering for quite a long time, which is why work at heights goes more smoothly.

And finally, new superdiffuse membranes. Their use allows you to create only one air gap between the film and the roofing - and all the condensation will come out on its own. This provides wind protection, protection of insulation, and effective removal of steam from the entire roofing pie. In addition, the membrane itself can be laid directly on the insulation without any additional sheathing - a valuable saving! See what a modern membrane looks like and how different it is from ordinary polyethylene film, even in appearance:

But purchasing a good roof membrane can be a challenge. Even if you contact an official dealer of a manufacturer with a memorable advertisement, it is not a fact that you will end up with a quality product in your hands. Sometimes unscrupulous sellers offer to look at advertising samples of films that have a noticeable rough structure and a certain color and appearance, but in the end they sell a roll of film with slightly different qualities. At the same time, when buyers try to deal with the “forgery,” they refer to the manufacturer’s legal right to change both the color and texture of the products at their discretion. Those. one thing is advertised, another is sold - not often, but this happens periodically in the construction market.

Therefore, when purchasing a superdiffuse membrane, be sure to check it for the following key characteristics:

• Vapor permeability: 0.02-0.03 m.
• Tensile strength: not less than 140 N/5cm.
• Tear-out strength: not less than 50N/200mm.
• Water resistance: degree W1, and the water column is greater than 2000 mm.
• UV stability: 3 months.

Based on these characteristics, membranes are divided into certain groups. Some can be placed directly on the rafters, others can only be in contact with the insulation. And the tensile and tearing strength is the durability of the film itself.

Roofing waterproofing

The process for materials such as metal tiles is carried out with all types of roofing, that is, insulated or not. The installation of a waterproofing membrane is able to perform the following functions:

• Protection from large amounts of condensation that accumulates on the insulation;
• Effective protection against large amounts of moisture in rafter systems. Waterproofing the entire attic or loft.

Important! The film used must contain small holes, which are designed to create effective ventilation air exchange in the installed
system.

The modern market offers a diverse range of high-quality films designed for metal tiles. Despite this, effective waterproofing of roof coverings on pitched roofs can only be carried out using special membranes.

This demand is based on high anti-condensation properties. The level of film density and its fire resistance and ultraviolet resistance must be selected with full consideration of the operational characteristics of the roof.

The process of fastening the membrane is carried out using a special stapler with special staples and strictly to the rafter system. A sheathing is mounted on top of the film, but it should sag no more than 2 cm, thereby providing the necessary ventilation gap that the roof needs.

Installation of additional elements

The installation of a metal roof does not end with laying the roofing material. To make the structure more durable, protected from atmospheric moisture and complete, it is necessary to install valleys, a ridge profile and cornice strips. The work is performed in the following order:

1. Install the ridge profile. It is attached to the sheathing along the ridge connection with roofing screws. To protect the ends of the profile from water ingress, a special seal is used.
2. Fix valleys and other valley elements. To protect the joints between the slopes and the junctions with vertical surfaces, special strips are installed.
3. Eaves and gable overhangs are equipped with special strips that protect from moisture and wind.
4. The eaves and gable overhangs are covered with soffits. These perforated panels protect the lower surface of the slope, not protected by waterproofing, from contact with water.
5. Install drainage, snow barriers and lightning protection.

Remember! Valleys, ridges, junction strips and gutters are not decorative elements of the roof. They perform the function of protecting the canvas from leaks, sealing it. Provided the roofing pie is properly equipped and auxiliary components are used, a metal tile roof will last 20-30 years.

Additional roofing elements for metal tiles

Metal tiles are used to cover pitched roof structures. It is laid on the supporting roof frame - the rafter system. Insulation of a metal roof It is recommended to carry out using a roofing pie made between the rafters. This technology is considered the most effective and gives excellent heat saving results.

We can say that in the end, the maximum preservation of heat depends on the filling of the pie. Properly selected and installed, it prevents cooling of the living spaces of the attic and attic, prevents the penetration of moisture from the outside and ensures its removal directly from the pie itself.

The main layers of the roofing pie

It is impossible not to note the roofing material itself – metal tiles. The extent to which the roof and the elements of the “filling” of its roofing pie will be protected from the aggressive effects and physical stress of natural phenomena, snow, rain, and wind largely depends on compliance with the technology of its installation. The safety, absence of wetting and effectiveness of the thermal insulation layer are ensured by waterproofing film, one or two ventilated gaps (depending on the type of waterproofing material) and a vapor barrier material.

Metal roof waterproofing designed to prevent moisture from entering from the outside. Depending on the purpose of the attic space, it can be either vapor-tight or vapor-permeable.

The waterproofing film is attached to the rafters at the top using staples or galvanized nails. In this case, it is necessary to allow a slight sagging of the canvas up to 1 cm in order to protect it during temperature changes. The sheets are laid across the roof slope with an overlap of the top sheet on the bottom sheet by 10 cm. It is desirable that the waterproofing material have high vapor permeability, otherwise it will be necessary to provide another ventilated layer in the roofing pie.

On top of the waterproofing layer, counter-lattice bars are laid along the rafters, and sheathing bars are laid across. The height of the counter-lattice bars is selected based on the length of the roof slope and the size of the required ventilation gap, and the pitch of the lathing in accordance with the horizontal wavelength of the metal tile, since the roofing material will be attached to it.

For a metal roof, it is especially important to have ventilation for the under-roof space. In its absence, condensation, which forms when the internal and external temperatures differ on the inside of the metal tile, can lead to disastrous consequences for the roof structure

For metal roofs, including those made of metal tiles, it is necessary to use special membranes - anti-condensation membranes.

This material is one-sided, and it should be laid with the rough side facing the insulation.

Thermal insulation layer of a metal roof It is recommended to make it from breathable materials, usually with a fibrous structure. They are based on basalt or fiberglass. These insulation materials have good thermal insulation characteristics and excellent noise reduction. Another advantage is that they are not flammable. The total thickness of the mineral wool layers under the metal tile roof of an energy-efficient house is at least 20 cm. Fiberglass insulation, due to its structure, has many air gaps, which ensures their low thermal conductivity.

In general, the performance characteristics of mineral wool and fiberglass are similar, although the thermal conductivity of fiberglass is lower.

Penoizol is also used as insulation - liquid foam, a new generation of thermal insulation material.

It is necessary that the thermal insulation mats or slabs be semi-rigid. This way they will hold well in vertical and inclined planes.

Their length should be 2–3 cm greater than the distance between the rafters. The number of layers of insulation to be laid is calculated depending on the thermal conductivity coefficient of the material used for insulation.

Vapor barrier layer of a metal roof protects the insulation from moisture that comes from inside. It is also attached to the rafters, only from below, using galvanized nails or staples. Similar to laying the waterproofing film, an overlap is performed. To ensure tightness, all “dangerous” junction areas, for example, to walls, pipes, windows, are taped with special tape.

The installation of the roof, insulation and other elements is carried out without deflections, gaps and irregularities with a tight fit to each other, with the exception of ventilation ducts.

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Choosing the right insulation

Here we come to the main question. For convenience, let's break it down into separate important points.

Sorptive humidity of insulation

Do you know why wet insulation quickly loses its thermal insulation properties? The fact is that the thermal conductivity of water is exactly 25 times greater than that of air - that's one, and the water itself seems to glue the fibers together - that's two. That is why, when choosing insulation for a roof, carefully study its three main qualities: sorption humidity indicator, vapor permeability and water absorption. After all, on a roof with metal tiles as a roof covering, the issue of dampness is acute. Not to mention the constant condensation on the metal surface, which always finds a way to get to the insulation through invisible holes in the waterproofing.

So, sorption humidity is the hygroscopic humidity of insulation under certain conditions. Those. the higher this value, the worse, because for roofing insulation, water-repellent properties are primarily important. And they are directly affected by the presence of special hydrophobic additives in the material.

For clarity, let's look separately at the issue of humidity in a typical home. So, according to sanitary requirements for residential premises, normal humidity is 30-45%, and 30% is the threshold below which the air becomes too dry and even unfavorable for health. But in European countries, 45-60% is considered normal humidity. But keep in mind that the humidity level in the house can reach 80%, especially if more than two people live together and the wall decoration is almost vapor-tight. The moisture simply has nowhere to go, and it rises up to the roof, which then leads to problems with the insulation, if you think through the roofing pie well. You remember how a metal roof loves to collect condensation under it?

Of course, all responsibility can be immediately shifted to the vapor barrier. For example, aluminum is considered one of the best:

Water-absorbing properties of insulation

But I’ll have to disappoint you a little: not a single vapor barrier in the world can protect the insulation 100%. Real figures are in the range of 70-80% if the vapor barrier is of high quality, and 50-60% if it is the simplest

And, if we take into account the fact that such insulation is still affected by condenser moisture on the other side (metal tiles again), then you need both high-quality vapor barrier and insulation, which, as far as possible, is not afraid of water and retains its properties for a long time even in such extreme conditions.

And this is already such a quality of insulation as water absorption - this is the ability of the material to absorb moisture upon contact with water and retain it. The lower the water absorption of the insulation, the better - this way it will stay dry for as long as possible, even with high dampness. In this regard, polystyrene foam, for example, is a leader among other insulation materials.

So, in addition to polystyrene foam, stone fiber naturally has water-repellent properties, which only need to be slightly enhanced. Here are step-by-step instructions on how to insulate such a roof:

Vapor permeability of insulation

And finally, vapor permeability is the ability of insulation to pass water vapor through itself and remove it out into the ventilation opening. This is one of the most important factors that affect the thermal insulation of a roof. And in such a roofing cake, vapor permeability should also be high!

Modern ecowool is one of the best in this regard:

Cleanliness of insulation

There is another problem: some insulation materials generate dust, and their lint particles, together with warm air, rise and gradually clog the vapor-permeable holes. As a result, over the years, the quality of even the best “breathable” membrane deteriorates. Therefore, it is better not to insulate such a roof with sawdust at all, like with cheap mineral wool. Only from well-known manufacturers!

And special under-tile fastening systems, which are just beginning to appear on the Russian market, but have long been recognized abroad, are well suited in this regard:

Let's summarize: the lower the indicators of water absorption and sorption humidity, and the higher the vapor permeability, the better the thermal insulation qualities of the material for insulating a metal roof. Choose the right material, study our photo instructions - and go!

Roofing pie for metal tiles

Installing a cold roof under metal tiles is one of the simplest options. In addition to supporting structures, such a roof includes roofing material in the form of metal tiles, lathing, and a layer of waterproofing. 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 this, it is pressed with wood screws, which will be used to attach the counter-lattice, the pitch 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 covering of sheets of plywood or chipboard is used.

Roofing pie diagram.

The waterproofing film (this can be a special PVC membrane or polyethylene film) should be laid on the roof with slight sagging. At the same time, ruptures 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, drainage of condensate from it to the eaves strip, and then into the drainage tray. If this is not done, the roof structure will be subject to the negative influence of moisture, and this will lead to destruction.

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

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

Roofing pie installation diagram.

1. On the side of the living quarters, first there is a layer of vapor barrier with one-way permeability, that is, condensation is released from the room, but does not penetrate inside.
2. The roof truss system, longitudinal purlins, that is, the supporting structure.
3. Waterproofing. The film should sag slightly to allow condensation to escape.
4. Counter-lattice, the installation of which is carried out parallel to the installed rafters. The counter-lattice boards press the waterproofing, providing its additional fastening.
5. The sheathing of a cold roof is made of wooden beams, 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 pitch may vary, as well as the material for the sheathing; it depends on what type of metal tile is used and what slope was chosen for the roof.
6. Metal tile sheets.

What else is needed?

To install a roof with this design, you need to take the simplest tools and materials that are not very expensive. In addition to wooden boards for constructing the rafter system, sheathing and counter-lattens, you should prepare a vapor barrier, a waterproofing membrane, and the estimated number of sheets of metal tiles. Staples, galvanized nails, wood and metal screws are used as fastening elements. When calculating steel sheets, you must remember that various additional elements may be needed, for example, ridge tiles, valleys, cornices, etc.

The design 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 when the attic space underneath is not used.

Organization of drainage

If you plan to equip the roof with a drain, then you should use eaves boards to strengthen the slope. They are laid along the overhangs in grooves made in advance in the rafters. It is to these boards that the hooks should be attached to fix the gutter, correlating their pitch with the pitch of the rafter system.

If the organization of an organized drainage system is not part of your plans, then a front board, which is attached to the ends of the rafters, is used to fasten the roofing elements along the edges of the roof. This end strip not only serves as a decorative element, but also prevents the metal tiles from rattling during strong winds.