Installation of metal roofing tiles with a cold attic. How to make a cold roof from metal tiles - installation instructions. Vapor barrier and ventilation of cold roofs

Currently, in newspapers and on Internet sites that provide information related to construction, a large number of offers for the provision of services that provide roofing installation for country houses and country cottages.

In most cases, they mean insulated roofing, which is often called a roofing pie. At the same time, there is almost no mention of cold roofing. And completely in vain, since it is she who represents optimal solution, especially for some type of buildings. In addition, this is a very affordable option for a wide range of the population in terms of its cost.
This article aims to provide information about in what cases it is better to install a cold roof and how to do it.

Typically, the decision to install a cold roof is due to financial considerations or the lack of great need for a warm roof. As an example, we can mention the construction of a country house in which it is not planned to have attic room. In this case, there is no need to insulate the attic. This option is acceptable for outbuildings, for which it is enough to insulate only the ceiling, leaving the roof cold. This example can also be modular houses, made up of block containers. The modules themselves are insulated. All you need to do is install a cold roof. It is quite clear that this type of roofing is quite suitable for country houses, sheds, gazebos, holiday houses and other structures. IN rural areas houses, as a rule, have non-livable attics and, accordingly, a cold roof, which allows saving significant money.

What is a cold roof?

In constructive terms cold roof does not present any difficulties. To protect the attic space from condensation that occurs on the inner surface of the roof, a membrane with waterproofing properties or a film is fixed to the rafters.
Before installation roofing covering, stuff the counter sheathing and sheathing. Exits are installed under the ridge and on the slopes, through which water vapor is removed from the space under the roof. Besides, dormer windows also serve for attic ventilation. The absence of difficulties during installation and subsequent operation of a cold roof is due to the simplicity of its design.
In the case when it is planned to insulate the attic or make an attic in the future, it is necessary to use a TYVEK type membrane for waterproofing, since micro perforated film, which is usually used when installing cold roofs, does not make it possible to ensure the necessary tightness of the insulation.
If the roof will not be insulated, then it is quite possible to get by using micro perforated film, which has a lower cost. Its installation provides for a sag of 20 mm, which ensures water flows into the middle of the purlin and protects the rafters from moisture. The waterproofing in the ridge area is broken in order to provide an outlet for air.
There is an opinion that in regions where there are severe winters, it makes no sense to install a cold roof. It is worth noting that it is erroneous. The history of cold roof and attic equipment goes back hundreds of years. The use of such roofs is possible in any area. It is only necessary to comply with the conditions for insulating the attic floor, which are required by the standards of the given area of residence. In regions where there are large readings of negative air temperatures, special attention should be paid to insulation technological equipment, which will avoid the appearance of condensation, which will inevitably lead to icing.
As a covering for cold roof Various can be used that do not require the installation of a solid base. A completely suitable option would be to use either a profiled sheet. They are distinguished by reliability, manufacturability and durability. Those that have a polymer coating are especially recommended, which can significantly increase the service life of the roof.
An example is Colorcoat-coated steel, which is produced in England by Tata Steel. The guaranteed service life is 20 years, while in reality such a roof will last at least 50. For those who believe that the profiled sheet does not meet their aesthetic needs, we can recommend the use of metal tiles. looks similar to natural material and at the same time is distinguished by its low weight and the absence of difficulties during installation.

Or maybe it's even simpler?

Of course, this is quite possible, especially if you have to install a roof on buildings that will not subsequently need insulation. The use of a profiled steel sheet with an anti-condensation coating will greatly simplify installation work, reduce costs.
This material has the structure of synthetic felt, which is applied during the manufacturing process to the back surface of the profiled sheet. The interweaving of polyester fibers creates air cavities in huge quantities. This structure gives the coating the ability to accumulate and retain large amounts of moisture, the amount of which can reach 1 liter per m2. An increase in air temperature leads to intense evaporation of water.
In this way, you can solve the problem of condensation that appears on the inner surface of the roof without using waterproofing. And although in this case there is some increase in cost roofing material, it is compensated by the absence of the need to install counter lathing, install a waterproofing film, and reduce the time required for installation by almost 2 times. At the same time, facilitating preventive examinations and current repairs roofs.
Installing a roof made of anti-condensation coating is similar to work using conventional corrugated sheeting. It does not require the use of special tools or specific skills. As a result, the use of this material for roof installation can reach 30% savings from the estimated cost.
The use of an anti-condensation coating can be a godsend for those who install a roof on buildings that do not have an attic floor. For the most part, this applies to buildings with a pitched roof. These can be verandas, garages, sheds, gazebos. They do not require the use of film to provide waterproofing. To all the other advantages of this type of coating, one can add a reduction in the noise of wind, rain and hail, by an average of 2 dB, easy cleaning from dirt, and the absence of fungus and mold.
Opportunities for original solutions
Nowadays, the market for construction materials is so diverse that for those who want to give their roof an original look, practically nothing is impossible. This statement can also be applied to a cold roof. The entry of a large amount of light into the attic, veranda or gazebo will be ensured by the installation of transparent inserts made of profiled polycarbonate. And canopies, if they are small in size, can even be completely transparent.
The advantage of a profiled sheet made of polycarbonate, undoubtedly, is its ability to transmit light, which lasts for 10 years of operation. To it you can add high resistance to low temperatures and mechanical stress, and the ability to reduce the intensity of ultraviolet radiation.
For cold roof interesting solution This may include the installation of hatch windows in non-residential premises, the purpose of which is to use them as emergency exits. Installing a row of these windows in the attic will allow you to use it as a dining porch or solarium. It is very convenient to sit in it during bad weather. This option, by the way, will be useful for those whose plot size does not allow installing a gazebo.

Cold roof, in which they find their combination design features and the ability to apply modern solutions and materials, allow us to consider it almost an ideal option for the construction of cottages and country houses. In addition, its installation is affordable for any ordinary consumer.

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::

roofing;
attic external walls (applicable for gable roofs with pediments);
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 top part no lower than 1.75 m from the floor in the attic. They can also serve as an exit to the roof of the house to inspect the roof, ventilation and chimney elements.

Steam and thermal insulation of a cold attic

For a roof with a cold attic, it is most important to minimize heat loss through the attic floor. For both wooden and reinforced concrete floors Vapor barrier is mandatory. It is laid on the ceiling itself and protects the insulation from vapors that can condense in the heat insulator 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 method 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.

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

The advantages of this option

The installation of such a roof is quite simple - you will need to erect a structure, lay a layer of waterproofing, lathing and counter-lattice, and a roofing covering. The main thing when erecting a cold roof is to provide a ventilation gap to allow condensed moisture to drain away. This is necessary to ensure that the supporting structure and roofing material do not deteriorate under the influence of moisture.

The installation of such a roof itself should not be accompanied by complications during the work; you just need to correctly fasten the roof covering so that it does not allow precipitation to pass through the joints into the under-roof space. Before creating a roof pie for a cold attic, it is worth performing the entire list of calculations, determining the slope of the slopes, the pitch of the sheathing, and choosing the appropriate method for fixing the metal tile sheets.

What is a cold roof?

The technology of cold roofing from metal tiles involves the initial construction of a rafter system, after which a membrane and polyethylene film will be laid on it to ensure waterproofing of the roof under the metal tiles. They fill the counter-lattice, the sheathing and lay the roof covering in the form of metal tiles.

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

Roof installation has the following features:

If over time you plan to install a warm roof, then the choice of membrane to protect against moisture must be careful. If you plan to install an attic, then a PVC membrane must be present.
If there are no plans to insulate the roof in the future, then it will be necessary to install micro-perforated waterproofing, which is used specifically for cold roofs. You cannot lay thermal insulation with such a film, however, in the case of further insulation, you will need to purchase a new membrane. Otherwise, in the future the roof will lose protection from moisture, the insulation will not have time to dry, and the roofing material will begin to rust over time.

Installation stages

Let's figure out how to properly install metal tiles so that they last a long time. When laying the membrane to protect against moisture, it should be taken into account that it should remain with a slight sag, about 20 mm. In this way, it will be possible to ensure the drainage of condensed moisture, thereby protecting the rafter system and other roofing elements from rotting. To allow water to evaporate in a timely manner without stagnating and thereby creating an unfavorable environment, care should be taken to include in the design a ventilation gap, which is placed between the moisture-repellent film and the roof ridge.

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

The design of the roof with a cold attic is such that it can be used in regions with any climatic conditions. Quite a lot of people believe that this type of roofing is not applicable to northern regions, although in fact this is not the case. Often in such regions, cold attic spaces are most often installed. The attic itself is insulated, and the cold roof does not in any way affect the internal microclimate of the upper floors. You don’t even have to use the attic, because laying a layer of insulation between the top floor and the under-roof space eliminates all the nuances that affect heat loss.

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

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

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 covering is very quick; the main thing is to understand how to cover a roof with metal tiles correctly. 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 from the cornice strip and further into the drain. Neglect of such 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.

Tools and supplies for installing a cold attic

It is noteworthy that laying metal tiles does not require overly complex professional construction tools. You can use a basic set that every man has in his household.

In addition to lumber for the rafter frame, sheathing and counter-lattice, an insulating membrane or film for vapor and waterproofing is required, as well as a sufficient number of metal tile sheets purchased from one batch.

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

As for laying the roofing, in addition to profile sheets, you will need ridge elements, valleys (internal and external), cornice and wind strips, as well as snow retainers and gutters.

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

Specifics of installing a cold roof made of metal tiles

Today, when constructing a residential building, they use various options roof structures, but the simplest is a cold roof. This device is perfect when the attic space is not used as additional living space. The very scheme of such a roof is very simple: load-bearing structures, waterproofing, sheathing and counter-lattice, plus roofing material.

Cold roof installation diagram.

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

The installation of such a roof itself does not differ in any difficulties, the main thing is to correctly fasten the profiled a metal sheet in such a way that precipitation does not penetrate through the joints under its surface. Before starting construction, you should make all the required calculations, calculate the angle of inclination, the pitch of the sheathing, and decide on the method of fastening the metal tile sheets.

Features of a cold roof

Cold roofing scheme.

A cold roof differs from a warm roof in its structure, although its design itself is extremely simple. The only thing that needs to be taken into account is the roofing option. When using metal tiles, a ventilation gap must be provided for proper removal of condensate from the under-roof space. This is done so that the steel sheet is not subject to corrosion.

The installation of a cold roof involves the installation of a rafter system on which a membrane or polyethylene film is laid for waterproofing. After this, the counter-lattice, sheathing and covering in the form of metal tiles are nailed.

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

The installation itself includes the following features:

If a device is planned in the future warm roof, then you need to be very careful when choosing a membrane to protect against excess moisture. For a future attic, only specialized waterproofing in the form of membranes made from PVC is suitable.
If further insulation is not planned, then micro-perforated waterproofing is used, designed specifically for cold roofs. Such a film does not allow thermal insulation materials to be laid next to it, that is, with further insulation, you will have to spend money on a new membrane. If this condition is not met, then the roof will be virtually unprotected from moisture in the future, the insulation will be constantly wet, and the roof covering will be susceptible to corrosion.

Sequence of work

Device diagram pitched roof without insulation.

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

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

An overlap must be made; the edges of the film must be secured with tape.

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

Diagram of a standing seam roof.

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

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

Roofing pie for metal tiles

Installing a cold roof under metal tiles is one of the most simple 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: on rafter system The waterproofing film is attached 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.

Scheme roofing pie.

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 negative influence 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. Cold attic therefore it turns out unusable.

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

Roofing pie installation diagram.

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.
The roof truss system, longitudinal purlins, that is, the supporting structure.
Waterproofing. The film should sag slightly to allow condensation to escape.
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.
Cold roof lathing is made from wooden beam, the cross-section of which is most often 50 by 50 mm. Its installation is carried out in increments of 35-45 cm along the slopes. The 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.
Metal tile sheets.

What else is needed?

To install a roof with this design, you must take the most simple tools and materials that are not very expensive. In addition to wooden boards for constructing the rafter system, sheathing and counter-lattice, 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.

Cold metal roofing

Metal roof installation

The beginning of the installation of metal tile roofs is to measure the slopes and establish the perpendicularity of the ends of the roof in relation to the lines of the ridge and eaves. The lathing for sheets of metal tiles is made of boards with a cross-section of 32x100 mm with a distance between the ribs of 350 mm, i.e. equal dimensions between the ribs of the metal tile. If the size of the transverse ribs of the metal tile is different, for example 400 mm, then the sheathing is arranged accordingly. On cornices, the distance from the outer edge of the cornice board is 300 mm (Fig. 144).

Boards at the end areas and boards of ribbed sheathing facing the eaves should be located higher than other boards. The edges of the sheets of metal tiles must be covered with continuous sheathing of boards to secure them firmly. Installation of metal tile sheets begins from the end sections. First, a guide board should be secured to the edge of the cornice. There will be a guide line from it. It is advisable to first secure 3-4 sheets with one screw on the ridge, align them along the eaves, then secure them completely: first attach the first sheet to the ridge, then the second sheet. Secure the overlap with a screw along the top of the wave. The groove on the edge of each sheet should be covered by the adjacent sheet. The edge with the groove of each subsequent sheet is placed under the previously laid, previous fixed sheet, which holds the sheet being mounted (if installation starts from the left end). To secure sheets of metal tiles to the sheathing, you can use self-tapping bolts A4 9x27 with seals or self-tapping screws with a sealing washer (6 screws per 1 m2). Drill the holes for the bolts with a drill. Bolts should be installed perpendicular to the sheets on every other corrugated fold, on the bottom of the groove and on the underside of the cross fold.

All further overlaps are performed at the transverse border of the sheet. The overlap length is approximately 250 mm. The overlaps are secured with bolts or screws. The ridge is covered with special ridge elements with a seal. They have a semi-cylindrical shape and fit well on the upper ends of the profile sheets of metal tiles (Fig. 145). The end elements protect the roof from rain and wind.

Eaves elements protect the cornice and sheathing from water leaking from the roof (Fig. 146).

To prevent the formation of condensation on the cold inner surface of the metal tile, conditions should be created for ventilation under the roof from the eaves to the ridge, and rolled material should be placed under the sheathing (Fig. 147).

Metal roof valleys are made using a special valley element. An intermediate structure is mounted on the casing located below. A valley element is bolted to this structure (Fig. 148).

The gaps between the metal tiles and the gutter element, as well as under the ridge in all places where there are leaks and gaps, are sealed using any silicone and other curing sealant, or using special sealing tapes nailed to the profile with small nails. When cutting a sheet or when drilling, the resulting metal chips must be swept away so as not to spoil the coating. During installation, you should wear shoes with soft soles and step only in the areas of the sheathing and in the deflection of the wave.

The sheets are fastened with bolts or screws in accordance with the diagrams. To access the roof, the metal tile sheets have an element with a hole made of fiberglass, appearance and the pattern of which is the same as that of a sheet of metal tiles. Installing a metal tile roof requires 30 different components. In addition, a ladder to climb to the roof, walkways, a ladder on the roof, drainpipes, hooks for gutters. Metal tile sheets are supplied by size. The length of each type of sheet should be equal to the length of the slope plus the cornice (Fig. 149). To ensure complete installation and reliability of the roof, factories supply the site with a wide variety of components, such as a rectangular ridge; semi-cylindrical ridge, ridge end element, end elements of cornices, external and internal corners, sheet structures for roof access, etc.

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Roofing made of sheet steel. Preparatory work

Waterproofing for roofs under metal tiles

Increased humidity under the roofing leads to rotting wooden structures roof and wetness of the insulating material. Damage to the structure of the tree leads to its destruction and large-scale and costly repairs cannot be avoided.

Roof waterproofing under metal tiles is designed to protect wooden elements and thermal insulation (if any) from moisture, which different ways can penetrate under the roof:

from condensation, formed on the inner surface of the metal tile due to high air humidity and/or penetration of moist fumes from residential premises into the attic;
from moisture penetrated through the holes in the fasteners.

depositphotos

Types of waterproofing films

All waterproofing roll materials for roofs under metal tiles are divided into two main types:

waterproofing films;
diffusion membranes.

The main difference between waterproofing films and diffusion membranes is that the former do not allow both droplet moisture and water vapor to pass through, while the latter retain droplet moisture, but are easily overcome by water vapor.

Waterproofing films are several times cheaper than membranes. Therefore, it is better to use them for moisture protection of a cold roof. This will reduce material costs without losing protective properties.

If the roof is insulated with mineral wool or other heat-insulating material, then it is recommended to use a diffusion membrane, which will release steam that has penetrated from the insulation, but will not allow moisture to penetrate into the insulation.

In addition to vapor permeability, waterproofing film materials also differ in other parameters: base material (polyethylene, polypropylene, etc.), density, strength, UV resistance, service life. Detailed review Read the films here.

The technology of waterproofing depends on the brand of material used and the type of roof - cold or insulated.

For a cold roof

A cold roof means there is no insulation in it. When waterproofing it, both a diffusion membrane and a waterproofing film with low vapor permeability - polyethylene or polypropylene - can be used.

* Strength - maximum tensile force in the longitudinal and transverse directions.

The film is laid directly on the rafters with a slight (about 20 mm) sagging. Laying is done in strips starting from the eaves upwards with the bottom layer overlapping the top layer by 50-100 mm. The joint between the sheets is sealed with adhesive tape.

If a “breathable” film is used, you need to pay attention to which side it is laid up, it depends on this correct work. This information can be found in the instructions for the material, usually the side with the logo should face up.

There should be a ventilation gap above the waterproofing film. To install it, counter-lattice strips 50 mm thick are nailed onto the rafters over the film, and the lathing is already attached to them.

For roofs with insulation

Waterproofing an insulated roof is more difficult and expensive. There are two options for waterproofing depending on the type of material used.

Waterproofing with two gaps

If a film with low vapor permeability is used, it is necessary to create two ventilation gaps - between the insulation and the film and between the film and the sheathing.

Typically, insulation is laid between the rafters flush with their top surface. Therefore, to create the first gap, you need to nail the counter-lattice strips to the rafters and lay the film on them without sagging. Then, strips are placed on top of the film to the counter-lattice, providing a second gap, and to them the lathing for the metal tiles.

The advantage of the two-gap method is that a cheaper waterproofing film can be used instead of a diffusion membrane.

The disadvantage is that it is more labor intensive. In addition, ensure double clearance in areas of valleys, chimney outlets and skylights it can be difficult and sometimes impossible.

Waterproofing with one ventilation gap

In most cases, it is more advisable to use this option, which creates only one ventilation gap - between the film and the sheathing.

To implement it, you will need a diffusion membrane that can effectively transmit water vapor, even when laid without a gap, directly on the insulation. It is attached to the rafters according to the usual rules - with the upper strips overlapping the lower ones and sealing with adhesive tape.

Membranes require installation with a certain side up.

But even if a “breathing” membrane is used, the ventilation gap between it and the sheathing must be ensured - using the same counter-lattice nailed to the rafters.

Strength*, N/50mm	Vapor permeability, Sd	Weight, g/sq.m	Note
DELTA®-VENT N	220/165	0,02	130	The best choice if funds allow
Tyvek Soft	165/140	0,02	58	Very light and reliable membrane from DuPont
YUTAVEK 115	260/170	0,02	115	Price quality
Izospan AM	160/100	0,03	-	Budget membrane, medium strength
Ondutis SA115	160/90	0,02	100	Better steam permeability than Izospan, but less resistant to UV rays

Is it possible to use roofing felt?

Our usual roofing material, which several decades ago was almost the only waterproofing material, is inferior in every way (except perhaps price) to new products for waterproofing.

Its service life is significantly inferior to that of modern waterproofing films; it burns well and emits a strong, bad smell. Experts do not recommend using it for waterproofing under metal tiles.

What makes metal roofing different: types, structure, layers

Metal tiles are a popular and reliable roofing material that appeared more than thirty years ago and today occupies one of the leading positions among roof coverings. country houses due to its advantages: lightness, durability, ease of installation, aesthetic appearance. Since the late 90s, metal tiles have become popular in Russia. It is a profiled sheet of galvanized steel with polymer coating resistant to ultraviolet radiation and aggressive environments. Using metal tiles, you can create exquisite roofs of complex shapes.

Types of roofing

Depending on the presence of insulation in the roof slopes, two types of roofing are distinguished: warm and cold.

A combination of layers of insulation, roofing, waterproofing and vapor barrier membranes, interior decoration It is commonly called a roofing pie.

A metal roof will significantly improve the appearance of any building.

If the roofing pie is not constructed properly, condensation will accumulate in the space under the covering, which will cause corrosion of the metal, dampening of the insulation and wooden structures. Moisture can penetrate into the roof elements in the form of steam from the premises of the building, in the form of precipitation, and also settle as condensation on the cold inner surface of the metal tile.

For normal functioning of the roof, each layer must be selected in accordance with the climatic characteristics of this region and laid according to technology. This is the only way to ensure the durability of the structure and the comfort of the inhabitants of the house. Failure to comply with this rule may result in consequences such as:

large heat losses;
uncomfortable indoor climate;
mold and mildew;
heating of the coating, which will lead to the formation of ice, icicles on the roof, and therefore to excessive load on the structure, which is dangerous for people.

The choice of roof slope is influenced by wind and snow loads on the roof

Cold metal roofing

The simplest, and therefore cheapest, design is the cold roof. Only the attic floor is insulated. The main thing that needs to be done is to provide a high-quality ventilation gap to remove accumulated condensate and to properly fasten all elements of the metal tile covering to prevent precipitation from penetrating through numerous joints.

The simplest and cheapest type of roofing is a cold roof.

Warm metal roofing

If living quarters are located in the attic, it is called an attic. To create conditions suitable for living, it is necessary to insulate the roof. Insulation is laid between the rafters, often in several layers. The construction of such a roof is more labor-intensive and expensive. Before starting work, it is necessary to determine the amount of insulation for local conditions. Usually its thickness is selected in accordance with SNiP and multiplied by the area of the slopes.

The only difference between a warm roof and a cold one is that the second does not use heat and vapor barrier material.

Roof layers under metal tiles

The most practical and cheapest type of roof for metal tiles is a wooden rafter system. It is very important to perform it correctly so that it can withstand all wind and snow loads and does not significantly change its geometric dimensions over time. Instability will lead to deformation of the metal tiles, the formation of cracks and other damage to the roof. It is recommended to make the slope angle at least 14°, otherwise a lot of snow will linger on the roof.

Roofing pie under a cold roof

After installing the load-bearing frame, the following steps are performed to create a roofing pie:

A waterproofing membrane or waterproof polyethylene film (also called condensate film) is laid over the rafter legs. The membrane easily allows steam to pass towards the ventilation gap and is laid without sagging, unlike the film, which must sag by about 20 mm to drain condensate away from wooden structures. But metal tile manufacturers do not recommend using diffusion and superdiffusion membranes for waterproofing to prevent steam condensation from interior spaces on the metal coating. The waterproofing is laid horizontally from the eaves to the ridge with an overlap of 15 cm and the joints, joints and junctions with other roof elements are sealed with adhesive tape. As a rule, all waterproofing manufacturers have a special tape. The material is attached to the rafters with a construction stapler.

Roof waterproofing film allows steam to pass through easily

Next, it is necessary to create a ventilation gap between the metal tile and the waterproofing, for which the latter is first pressed to the rafters with counter-lattice slats, onto which the sheathing is then laid. Typically, a 50 by 50 mm beam or a 25 by 100 mm or 32 by 100 mm board is used. The boards are fastened in increments depending on the width of the transverse waves of the metal tile, so that the boards are located just below the break of the wave. The distance between the first two elements, counting from the bottom, is made a little smaller in order to be able to release the metal tile sheet over the edge of the cornice. The ridge part of the sheathing is usually double. In places where the valley passes (the internal junction of two roof slopes), as well as other massive structures on the roof (stairs, bridges, snow guards), the sheathing is made continuous.

After laying the waterproofing, a ventilation gap should be created

By the way, for some types of buildings (for example, utility or office premises), the lack of waterproofing may be justified. Its main purpose is to protect the internal space from water from the side of the tiles. If there are no sources of steam in the room, the roof is well ventilated, or if you are confident in the quality of the metal tiles, you can save on waterproofing. In any case, you need to be aware of the risks and think everything through carefully so that you don’t have to re-lay the metal tiles later.

Before laying metal tiles, do not skip important steps - laying the membrane and creating the sheathing

Roofing pie for a warm roof

IN warm roofs Insulation and vapor barrier are laid under the waterproofing. In this case, the sequence of layers is as follows:

Metal tiles.
Sheathing and counter-lattice forming a ventilation gap.
Waterproofing.
Additional ventilation gap.
Thermal insulation, possibly with the formation of additional sheathing.
Vapor barrier.
Another lathing for attaching interior trim.

The first three points in this list are similar to a cold roof with minor features of installing waterproofing, which are created by the presence of insulation in a warm roof:

installation of a superdiffusion membrane is carried out directly over the insulation;
the diffusion membrane is attached without a tight fit to the insulation, so as not to disrupt its vapor-conducting ability;

When installed, the superdiffusion membrane should not fit tightly against the insulation

Nowadays there is a huge amount of thermal insulation materials on the market. for various purposes, characteristics and prices. When installing, you should take into account their features and be sure to follow the manufacturer’s recommendations.

As thermal insulation under metal tiles, glass wool or mineral wool based on basalt is used, which are also sound insulators, have good fire-fighting properties and vapor permeability. Mats of such insulation are easily laid between the rafters, covering difficult areas of the space under the roof, unlike polystyrene foam boards. In order for thermal insulation to retain its properties, it must remain dry. all year round . The minimum thickness of insulation should be 150 mm. At the same time, to organize a ventilation gap between the waterproofing and the insulation, the width of the rafter board must be 30–50 mm greater than the thickness of the latter, otherwise the ventilation gap is created by an additional counter-batten along the rafters. It is recommended to make the distance between them 10–20 mm less than the width of the insulation mat (usually 600 mm) for more dense installation. If it is laid in several layers, then each subsequent layer should overlap the joints of the previous one in order to avoid cold bridges. When laying the insulation, it is not recommended to strongly crush or deform it, otherwise it will lose its properties.

When constructing a roof with insulation, it is necessary to comply with the technology

It should also be said about the disadvantages of cotton insulation. Firstly, this is the dependence of their characteristics on moisture content. No matter what kind of hydro-vapor barrier we use, over time the material will gain moisture. Secondly, such insulation materials generate dust, and this process intensifies as they deteriorate, so it is necessary to take care of the high-quality protection of residential premises from dust. Thirdly, in cold areas, the layer of mineral wool or glass wool when insulating roofs can reach 250 mm or more, which requires the organization of additional lathing for its installation, and therefore leads to increased costs.

After the insulation has been laid, it is covered with a vapor barrier membrane on the side of the room and lathing for interior decoration is attached.

Video: brief instructions on the basics of installing layers of roofing pie

Building a roof under metal tiles does not require special knowledge and skills, but it is labor-intensive. It is advisable that the work be carried out by a team. Therefore, it is recommended to order the installation of large-area roofs from construction organizations. It is better to first clarify whether the selected company cooperates with manufacturers of building materials or has its own production. As a rule, such companies try to strictly adhere to construction technologies.

Today, when constructing a residential building, various roofing design options are used, but the simplest is a cold roof. This device is perfect when the attic space is not used as additional living space. The very scheme of such a roof is very simple: load-bearing structures, waterproofing, sheathing and counter-lattice, plus roofing material.

The installation of such a roof itself is not difficult; the main thing is to correctly fasten the profiled metal sheet so that precipitation does not penetrate through the joints under its surface. Before starting construction, you should make all the required calculations, calculate the angle of inclination, the pitch of the sheathing, and decide on.

Features of a cold roof

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

The installation itself includes the following features:

If you plan to do so in the future, you need to be very careful when choosing a membrane to protect against excess moisture. For a future attic, only specialized waterproofing in the form of membranes made from PVC is suitable.
If further insulation is not planned, then micro-perforated waterproofing is used, designed specifically for cold roofs. Such a film does not allow thermal insulation materials to be laid next to it, that is, with further insulation, you will have to spend money on a new membrane. If this condition is not met, then the roof will be virtually unprotected from moisture in the future, the insulation will be constantly wet, and the roof covering will be susceptible to corrosion.

Sequence of work

An overlap must be made; the edges of the film must be secured with tape.

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

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.

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, it will be subject to the negative influence of moisture, and this will lead to destruction.

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

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.
The roof truss system, longitudinal purlins, that is, the supporting structure.
Waterproofing. The film should sag slightly to allow condensation to escape.
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.
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.
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-lattice, 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.

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- This , . 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 also mandatory for heated houses year-round residence, 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 the condition for its evaporation and weathering occurs. Therefore, waterproofing is not needed for a cold slate roof.

An example is apartment buildings Soviet-built - most “Khrushchev” buildings have slate 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 houses permanent residence roofing made of slate and ondulin without waterproofing is considered insufficiently reliable. 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. It's kind of metal tiles with a small leaf size. The differences lie in the composition of the protective and decorative layer. As for any metal roofing It is necessary to lay waterproofing 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 uninsulated roofs if there are plans for further insulation and the attic is in use.

Diffusion membranes. Good waterproofing properties and average vapor permeability. 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 installed 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 designed for waterproofing flat roof over a continuous floor.

In the technological map of the TechnoNikol company for the installation of bitumen roll materials It is indicated that the roofing felt 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.