Rafter system for metal tiles. Correct calculation of rafter spacing for metal tiles Construction of a roof frame for metal tiles

Metal tiles are one of the modern materials for roofing, combining an impressive appearance and affordable cost with a number of important technological advantages. The process of installing it is not too complicated: after familiarizing yourself with how to install a roof deck made of metal tiles, you can do such work with your own hands.

Of course, another option is always possible: save yourself the hassle by entrusting all the work to professionals. However, such a choice will cost much more, as a result of which not everyone will like this alternative.

So, if, after weighing all the pros and cons, we decided that we would cover the roof with metal tiles ourselves, then first of all we should familiarize ourselves with the technology and features of this process.

Characteristics of metal tiles

Metal tile material is a type of metal profile product that has a wavy surface characteristic of tiles. Its sheets are made from galvanized steel, and then a coating of polymer compounds is applied to them, giving the products an impressive appearance and resistance to adverse external factors.

Metal tile roofing has a number of important advantages, including the following:

High strength, resistance to mechanical and wind loads.
Light weight products and ease of installation. Covering a roof with metal tiles is not difficult; it does not require too much physical effort or the development of too complex skills.
Aesthetic appearance.
High resistance to corrosion processes.
Long service life of several decades.
Affordable price.

Having carefully studied the technology and procedure for covering a roof with metal tiles, you can carry out this work yourself, saving noticeably. It would be worth noting that the cost installation work accounts for more than a third of the total costs of roofing.

Composition and design of metal tile roofing

Laying metal tiles on the roof is the process of installing a multi-layer structure consisting of the following parts:

A vapor barrier layer, represented by a film that allows steam to pass through, but blocks condensation and water to prevent the insulation from getting wet. The vapor barrier film is laid on the lower surface of the rafters, after which it is secured using a construction stapler.
Rafters, the quantity and strength of which largely determine reliability roofing generally. You should accurately calculate the attachment points of the rafters and the distance between them, and then carefully install them.
A layer of insulating material that is attached between the rafter legs of the structure. For this reason, the width of the insulation should be taken into account when arranging the rafter frame.
A waterproofing layer, the material of which is laid over the rafters and protects the wooden frame structures from exposure to moisture or condensation.
Lathing used for subsequent laying of metal tiles. Its function is to evenly distribute the weight of the roofing covering.
Metal tiles laid on top of the sheathing structure, followed by fixation using self-tapping screws.

It should be noted that metal tile roofing can be of two types: cold and warm. The cold roof does not contain vapor barrier and thermal insulation layers. Naturally, such a roof will cost much less, but with this option, heating the attic and upper floor will present significant difficulties. Therefore, if the question is how to cover an attic roof with metal tiles, it is better to use a warm roofing option.

Stages and procedure for installing a metal tile roof with your own hands

To ensure the reliability and long service life of a metal tile roof, you must first study in detail the features and rules of installation work, and then adhere to them during the installation process.

If we take a closer look at the question of how to properly cover a roof with metal tiles, the step-by-step instructions for this work are as follows:

Arrangement of rafter structures. The rafter frame can be metal, but more often it is made of coniferous wood, which is impregnated with an antiseptic and fire retardant. First, the support beam of the Mauerlat is installed, which is fixed using anchor bolts or metal pins mounted in the concrete. Next, the timber ties that secure the Mauerlat are installed at a distance of 1-1.2 meters from each other. After this, vertical posts are mounted in the middle of each of the strings, at intervals of 1-1.2 meters, using temporary supports for them. Then a ridge beam is laid on top of the racks, onto which the rafter legs are then attached. The distance between the rafters can vary, usually from 60 to 120 centimeters, and depends on the weight of the roof, the thickness of the rafters themselves and the width of the insulation.
Covering the rafters with a layer of waterproofing material, which is laid horizontally, with some sagging and without tension, in order to avoid breakthrough under the weight of water. The waterproofing material is attached directly to the rafters using staples or stainless steel nails with a wide head.
Installation of lathing, for the construction of which they are used wooden slats about 3 centimeters thick, or sheets of moisture-resistant plywood. The spacing between the sheathing elements can also vary depending on the weight and steepness of the roof - for flatter roofs this distance should be smaller, and the sheathing itself should be stronger.
Installation of an eaves strip, to secure which a front board is mounted in the area of the roof eaves to the ends of the rafters. The cornice strip is laid on top of the front board and fixed with galvanized nails.
Installation of a vapor barrier layer, which is then covered with a layer of thermal insulation. Vapor barrier material laid on the lower surface of the rafter legs, and the subsequent installation of insulation is carried out between the rafter elements. Can be used as a thermal insulation material mineral wool, glass wool, polyurethane foam, polystyrene foam, etc.
Installation of additional valley elements, which are fastened to the sheathing structure.
The flooring of the metal roofing itself. This process also includes several stages. First, if necessary, metal tile sheets are cut to fit the surface to be covered. Then the bottom row of sheets is laid out, with an overlap of 10-20 centimeters. Next, the subsequent rows are laid. It is advisable to treat the joint areas between the sheets with sealant to prevent water leakage. All sheets of metal tiles are secured using galvanized self-tapping screws with a press washer.
After completion of the laying of the main part of the roof structure, the installation of ridge, end and other additional elements is carried out, as well as the installation of the roof drainage system.

How to roof different types of roof

Although in general the installation of metal tile coverings has much in common, regardless of the roof structure, nevertheless, for certain types of roofs this process may have certain differences and nuances. For example, for someone who is going to cover a hipped roof with metal tiles, or is thinking about how to cover a sloping roof with metal tiles, it is important to study some additional features in this matter before getting down to work. Otherwise, during installation and further operation you may encounter quite significant problems and unforeseen situations.

The classic and simplest roofing options are single-pitched and double-pitched structures. When looking for a solution on how to cover a gable roof with metal tiles with your own hands, you just need to follow general plan the work outlined above. The answer to the question of how to cover a pitched roof with metal tiles is even simpler. In this case, there is no need to equip the ridge and valleys, and all that is required is the direct installation of the roof itself. You just need to remember that pitched roofs can be with or without an attic, and like other roofs, they can be equipped with either an insulated or a cold version.

It is somewhat more difficult to install multi-pitched roofs, as well as roofs with complex structures. This may include, for example, covering the roof of a sloping roof with metal tiles. Broken roofs can have different numbers of slopes that continue each other, increasing the interior space and comfort of the living space as a whole. The process of arranging a sloping roof made of metal tiles with your own hands is generally the same as for conventional roofs, however, it is additionally required to close the joint areas that can allow water to pass through during precipitation. In this case, the waterproofing is laid along the slopes, and in the same way you can install insulation material and lathing.

In the case of complex roofs with four or more slopes, it is recommended to use special steel elements that support the rafters and keep their location unchanged. The use of strong steel supports is also desirable for the most loaded ridge beams. It should be noted that hipped roofs differ from gable roofs in the absence of gables, instead of which additional triangular slopes are installed at the end sections. This type of structure is more difficult to install, but is characterized by greater reliability and durability.

Finally, it should be taken into account that building a roof with your own hands may require builders to use non-standard solutions and ideas, practical choice which always depends on a particular situation.

How to cover a roof with metal tiles: we lay a gable and hipped roof with our own hands, how to cover it correctly, step-by-step instructions

DIY metal roofing

Metal tiles are one of the popular roofing materials, which are characterized by reliability, durability and affordability. In order to carry out high-quality work on covering the roof with metal tiles with your own hands, you must follow the instructions below. But first, let's look at what is so remarkable about this material and what disadvantages it has.

Advantages and disadvantages of metal tiles

Among the advantages of this coating are:

Light weight, which allows you to cover the roof without much effort;
The work will not cause difficulties and no special training will be required; it is enough to have basic knowledge in this area;
The service life is very long, which allows for a long time don’t think about covering;
Affordable price and high wear resistance are no less important criteria when choosing a roofing material;
Such material does not burn, and under the influence of high temperatures does not melt or deform;
A huge selection and stylish appearance will allow you to find suitable option everyone without exception.

The only drawback that many buyers cite is its noise. But even this can be dealt with if you take care of sound insulation when covering.

We cover the roof with metal tiles correctly: step-by-step instructions

To do this work yourself correctly, you must follow all the rules outlined in the step-by-step instructions. So, where to start:

Carry out the necessary calculations to find out the amount of materials, not forgetting about the insulation and fasteners;
Cover around the chimney;
Lay the material using one of the options.

Calculation of the amount of metal tiles per roof

Typically, the width of a full sheet is greater than the working area. This difference can be from 80 to 120 mm. therefore, when purchasing material you need to know exact dimensions working covering.

To perform the calculation correctly, you need to focus on the following formula:

The greatest length of the material is divided by its width. The resulting figure must be rounded upward.

First you need to measure the length of the slope, while the overhang of the cornice must also be taken into account;
The overlap is 0.15 m per row. If it is possible to lay the coating in one row, then the overlap does not need to be taken into account.

Having measured both indicators, they are added together.

If the purchased metal tiles were made to order according to certain sizes, then in order to correctly calculate all the indicators it is better to use the help of specialists.

The sizes of such material range from 70 cm to 12 meters.

But the most optimal option would be a coating with dimensions of 4 - 4.5 m.

Apron equipment

Where the chimney passes through the ceiling, care should be taken to take care of the inside of the junction.

Do-it-yourself installation of the apron should be done according to the following scheme:

The base material must match the color of the strips;
The groove made in the pipe should be about 15 cm deep, and the slope should be slight;
Heat-resistant insulation must be installed on the chimney pipe. The place of contact must be glued with tape;

Where chimney passes the roof level, it is wrapped with a special film.

A decorative apron can be installed when the sheets of metal tiles are laid on the roof. External abutment slats are placed on the chimney so that their upper part moves into the prepared groove. For more reliable protection, the joints are filled with heat-resistant sealant. And the lower part of the slats needs to be attached with self-tapping screws to the sheathing.

And to protect the brick chimney from possible cracking, the pipe must be wrapped with polymer-coated steel with your own hands. To ensure good ventilation, it is necessary to leave a small gap, about 20 mm.

Chimney with round must be insulated where the roof surface passes. To do this, you can take a special tape that has the ability to self-expand. It perfectly seals all holes, including the entire diameter.

Installation of metal tiles: sequence of work

To ensure that installing the roofing yourself does not cause much difficulty, you need to take care of the method of supplying the metal tiles to the roof. To do this, it is recommended to make logs.

If the roof is large or it is not possible to store all the purchased material near the house, then you can try to make a kind of rack with your own hands. All materials will need to be transferred there, and then installed. To prevent the sheets from being damaged during storage, they must be arranged with slats during moving.

As soon as the metal tile is in place, the protective film coating should be removed.

If you have to walk on laid material, you need to know how to do it correctly so as not to damage it. The first is caution. Before you step on anything, you need to carefully select a place for it. Secondly, movements should be carried out only along the sheets and step only between the waves of material.

If you need to walk across the covering, then the place where your foot will step should be a fold. Thirdly, you need to wear soft shoes when covering the roof, this will help avoid damage to the material.

If you have to cover it in rainy weather, then water may get into the joints. All moisture is squeezed up under the force of the second sheet. To completely eliminate moisture accumulation, each sheet of material contains a special groove, which helps drain unnecessary water. There are some species that have such a groove on both sides, but mostly it is on one side, on the right. When laying sheets of metal tiles, you should ensure that this groove is covered by the subsequent coating.

Having laid the beginning of the row, you can continue to cover in any direction:

The direction of installation is chosen for personal reasons regarding convenience. But the beginning of installation should begin from the side on which there are no cuts or bevels. You need to cover, focusing on another roof slope or valley.

If the process begins on the left, then the sheets laid after should lie on the wave of the sheet in front of it. And the groove should be on the left side of the coating.

If the laying principle provides for a direction from the right, then the groove is overlapped using the edge of the next sheet, ending up under the wave of material. The second method of covering is much easier and simpler, since shifting of the laid material is eliminated. But it is also very easy to scratch.

Whatever method of laying this work is carried out, the initial sheets should be placed parallel to the cornice, and the length of the overhang should not be more than 50 mm.

You can cover the roof with sheets using two technologies:

Place the material in one row;
Perform multi-layer styling.

How to lay metal tiles in one row

This technology involves installation to the right of the edge. This means that the coating should be leveled, focusing on the ends and cornices. When the first sheet is aligned with them, it needs to be fixed in the middle, not far from the ridge. Subsequent materials are applied with slight overlap. Usually, one wave of sheet is enough for good strength. After aligning the second sheet in relation to the first, it is also fixed, but not in the middle, but together with the previous sheet. Using this method, blocks of 4 sheets are laid out. The resulting block is aligned with respect to the cornice and end and, leaving room for overhang, the entire structure is attached to the sheathing boards. Last page You need to fasten it in the block when the last block has been adjusted. In the figure below, you can take a closer look at this installation method.

Multi-row fastening method

This installation method involves covering the roof according to the following scheme:

The roof needs to be on the right side. The initial sheet must be leveled relative to the end and cornice. Another covering element is mounted on top and attached to the first sheet, after aligning the two sheets. The next sheet must be mounted to the left of the first covering element, and also fastened to it. The fourth element should be laid on top of the third, and this continues until the end of the roof. Having completed two rows of such covering, the block is fixed on a wooden crate.

In the figure below you can see the described circuit.

Laying material on the ridge

Before installation begins, markings should be made on the slope and the central axis should be determined. On one sheet of metal tile you should do the same, mark the central axis. Place the surface of the slope and the sheet of material together; the latter must be secured with a self-tapping screw. Subsequent sheets should be laid on both sides of the ridge using one of the above methods.

What points you need to pay attention to

Metal tiles should be fastened only at the point where the sheathing boards touch;
The bottom sheet must be mounted, passing one wave over the step;
Subsequent rows are fastened at a short distance relative to the steps;
When attaching the material from the beginning of the end board, it is necessary to use all the waves;
The laid material must fit tightly to the sheathing boards;
When covering vertically, the material is secured using self-tapping screws into the recess of the waves.

Having examined the process of covering the roof with sheets of metal tiles with your own hands, you need to pay attention to the processing of the sheets.

It is prohibited to use a grinder when working with metal tiles, as the coating can be damaged, and this will lead to further corrosion. For these purposes, it is recommended to use cutting electric scissors or a jigsaw. A hacksaw for metal work is also suitable.
Areas of damage to the material must be treated with paint to avoid further rusting.

In the figure below, you can see how to lay the material yourself.

In the picture shown, number 3 means waterproofing film;

Number 4 means sheathing;
Number 21 - end board;
Number 22 - outer corner;
Number 23 - self-tapping screw.

End strip

If it is installed correctly, then it serves not only as decorative element, but also as a protective one. It allows you to protect fasteners from the harmful effects of environmental factors. Preventing moisture from entering is also within her purview.

It is intended for refining external joints. Removing excess moisture is also within its power. When attaching the upper valley, it is necessary to ensure that the screws do not damage the lower valley; this can lead to damage to the waterproofing.

straight.

If the roof has a slope with a straight bend, then the sheathing boards should be placed fairly close to each other. The coating material must cover the area of the direct fracture, with a small protrusion.

If the roof has a reverse bend, then it is necessary to use a wall connection, which will act as a connecting element. Where there is a reverse break, the sheathing boards should be fairly close to each other. And between the metal tile and the junction there should be a layer of sealant.

Construction of a gable roof rafter system for metal tiles

Metal tiles are a lightweight, durable, effective roofing material that ideally solves the problems of low-rise construction. Its steel endurance is perfectly combined with undeniable technological advantages. Laying large-sized sheets is done tens of times faster compared to piece-meal competitors. It lasts a long time and does not require a powerful base. You can install the roof and build a simple frame for installation with your own hands. There will be no difficulties in work if you know how a gable roof is structured - the rafter system for metal tiles and the installation process must take into account the technical and technological features coverings.

Metal tiles - roofing with an “iron” character

Metal tiles belong to the class of rolled products. In essence, it is the old familiar sheet steel, profiled in two mutually perpendicular directions. The longitudinal and transverse waves formed as a result of profiling give the sheets a similarity to the ceramic roofing prototype. The outer side is equipped with a colored polymer film that performs protective and decorative functions.

Disadvantages of the material and ways to eliminate them

The ability to imitate roofing ceramics did not rid the material of the standard disadvantages of metal. Thin sheets quickly heat up under the sun's rays and quickly say goodbye to the heat at the slightest drop in ambient temperature. There is no insulation: heat and sound waves easily penetrate inside the steel roof and go outside unhindered. The list of disadvantages is significantly supplemented by the ability to collect condensate due to the difference in the thermal properties of the coating itself and the rafter frame elements in contact with it.

Low insulation performance and condensation are two “scourges” metal roofing. You can get rid of them by arming yourself with information about the proper construction of a frame with a correctly laid roofing pie. If the installation of the rafter system for metal tiles is carried out in accordance with all technological requirements, complications with laying the material and operating the structure will not arise.

To ensure that the traditional behavior of a steel roof does not bother owners and does not cause premature wear, it is necessary to correctly distribute the layers roofing pie. Responsibility for distribution lies with the rafter system, the list of responsibilities of which includes:

Retention of the components of the roofing pie, which are laid on top, below and between the rafters.
Formation of air channels that eliminate condensation, and often the possibility of its occurrence.
Preparation of a number of supports aligned in one plane for the installation of future slopes by laying profiled sheets.

If we figuratively compare the roofing system with a living organism, then let’s say this: the “patient” will live and function normally only with a healthy supporting apparatus. In our case with a rafter frame. The method of dealing with the shortcomings of a steel coating lies precisely in choosing and strictly following an impeccably suitable installation scheme for the rafter system for the subsequent installation of metal tiles.

Types of rafter systems for metal roofing

Roofs with metal tile covering are erected over permanent and temporary residences. Gazebos, verandas, and bathhouses covered with metal “scales” look interesting. Depending on the purpose of the structure and the conditions of its operation, roofs with metal tiles are installed with or without insulation. The presence of thermal insulation is closely related to the structure of the rafter frame:

For insulated roofs, a system is constructed that includes three insulating layers and one or two ventilation circuits.
For cold roofs, a system with one insulating layer and one ventilation circuit is installed.

Insulated roof structures are erected if planned all year round actively use the attic. The rafter frames of warm roofs are designed so that the insulation boards are located in the space between the rafters. Analogs without insulation are installed on small dachas and buildings intended for temporary residence.

A roof without thermal insulation is also constructed in the case of insulation attic floor. For example, above a bathhouse or residential building with a low attic space that is clearly not intended for use, it is more reasonable to lay insulation between the ceiling beams or above them.

In the construction of rafter frames, rolled metal and lumber are used for laying profiled sheets. Hardware properties are closer to coatings, but wood is more suitable for the tasks of private construction. It is easier to work with it for an independent owner who has decided to build and cover the roof with his own hands.

It’s easy to make all the frame elements yourself from lumber, assemble and connect them into a rafter system. Wood is warmer and more attractive in terms of environmental aspects.

Advantages of a gable design

The simplest option for constructing a rafter system for laying metal tiles is rightfully recognized as a design with two slopes. Her rectangular planes ideal for laying sheets of similar shape. A hip or broken mansard roof will require much more effort and diligence. Many owners are depressed by the increased consumption of large-sheet material for roofing structures with full-length and shortened hips, and are not happy with the complexity of cutting.

Manufacturers claim that the optimal design for laying metal tiles will be a design with a slope angle of 12 to 15º. Structures of lesser steepness must be equipped with a reinforced waterproofing carpet. On steeper roofs, the number of fasteners increases and the installation step decreases. In both situations, the budget for the arrangement will be increased due to the purchase of additional insulating materials and hardware products.

Depending on the size of the metal tile and the dimensions of the structure being installed, the sheets are laid in one, two or more rows. Laying in one row is a priority, because transverse seams reduce insulation parameters and are potentially dangerous for leaks. Manufacturers consider the best sheet length for arranging the roofs of private houses to be 4-4.5 m. Among the offers of most metal tile suppliers there is a very popular service for cutting sheets to size, which is incredibly convenient for laying on slopes with custom sizes. The length of the sheet is equal to the sum of the length of the slope and the length of the overhang, which is 0.4-0.6 m, depending on the architectural solution.

The metal tiles are mounted on the sheathing, which in turn is attached to the rafter system. Lines of all structural parts gable roof strictly vertical and horizontal, which significantly facilitates the process of laying profiled sheets with similar edges. If the rafter system is built without flaws, then there will be no problems with installing the sheathing and roofing.

Construction of the rafter system

We found out that the rafter system works in tandem with the roofing pie. The layout of the rafter frame is directly related to the number of “cake” layers. Let's analyze the most complex insulated design option and find out which components we do not need to build a cold roof.

The rafter structure of a gable roof is a series of alternately installed pairs of rafter legs, the design features of which depend on the architectural data of the box being equipped. The manufacture and installation of a gable roof truss system is carried out in accordance with the rules regulated by:

Layered technology, requiring two specific supports for the top and bottom of each rafter leg. It is used if the building has an internal load-bearing wall or rather powerful columns are installed instead. The use of the layered method is allowed if the ridge girder racks can be installed on floor beams with high load-bearing capacity or if the floor is made of reinforced concrete slabs.
Hanging technology, requiring support only for the bottom of the rafter legs. The top of the elements of the hanging rafter system rests against each other in pairs. It is used if the box does not have an internal load-bearing wall and the ability to install supports under the ridge girder.

Option 1 - rafter frame for a warm roof

The use of insulation forces one to resort to technological tricks, thanks to which the layer important for the structure can retain its insulating qualities. And they will inevitably shrink when wet, because... The water that appears in the body of the material will facilitate the passage of heat waves.

Water appears in thermal insulation in three situations:

Penetration of household fumes attacking thermal insulation from inside the structure being used.
Formation of condensation due to the difference in temperature outside the building and in the attic.
Leaks observed during snowmelt and heavy precipitation, resulting from non-compliance with technology and operational errors.

A properly laid roofing pie, correctly distributed and securely fixed by the rafter system, is simply required to eliminate the listed misfortunes. In addition, the responsibilities of the truss structure include the formation ventilation ducts, through which air flows wash the thermal insulation and the inner surface of the metal tile.

Ventilation channels created by installing lathing and counter-lattice create conditions for regular ventilation and removal of condensate from the space under the roof, thereby prolonging life cycle the roof itself and the wooden parts of the rafter system.

If we imagine a conventional cut of a warm roofing pie with a rafter system from the inside of an already finished structure, then the sequence of layers and ventilation ducts will be as follows:

Lining, plasterboard panels or similar material used for interior decoration attic space.
Internal lathing designed to secure the vapor barrier layer to the rafters.
Vapor barrier that prevents household fumes from penetrating into the insulation.
Rafters between which insulation is laid. The width of the rafter leg should be 3-4 cm greater than the thickness of the thermal insulation. In other words, the specified gap for ventilation must remain between the upper plane formed by adjacent rafters and the outer surface of the insulation. If the thickness of the insulation is equal to the width of the rafters, i.e. The thermal insulation lies flush with the conventional plane of the slope; a lathing made of timber with a side of 30 or 40 mm is nailed to the rafter legs. This will create the required gap.
Waterproofing, which is laid either on the rafters, if there was no need to install a counter-lattice, or on a counter-lattice. Classic polyethylene waterproofing film It is forbidden to come into contact with the insulation so that moisture does not appear in the body. Waterproofing materials of the class of polymer diffuse membranes are allowed to lie directly on the insulation, because they are able to let excess moisture out without letting it in. Therefore, when using polymer membranes, there is no need to create a ventilation channel between the hydro- and thermal insulation.
External sheathing that simultaneously performs three significant functions. It is used for fastening waterproofing, to form another vent between the waterproofing and the metal covering and serves as the basis for installing sheets of metal tiles.
Finish coating.

Bitumen varieties of rolled materials cannot be used as waterproofing of roofing systems under metal tiles and corrugated sheets. When heated, the insulation and roofing will release substances that destroy each other's structure.

Let's summarize. A standard roofing pie for an insulated roof has three layers and two ventilation circuits, if classic waterproofing was used in construction. There are three layers and one ventilation channel in a cake with polymer diffuse waterproofing. All components are attached to the rafter system, which must withstand the weight of the materials and the snow load. For the domestic middle zone, the total load is approximately 200 kg/m².

Most often, rafter legs for metal roofs are made from boards with a cross-section of 50×100 or 50×150 mm, if the rafter installation step recommended by the material manufacturer has been followed. If the distances between the rafter legs are greater than the recommended value, the cross-section of the outer sheathing should be increased.

Option #2 - rafter structure for a cold roof

The diagram of a roof structure without insulation clearly confirms that it does not contain a heat-insulating layer. This means that there is also no need to install all types of insulation protection from getting wet. However, waterproofing is still needed to protect the wooden rafter system in case of leaks. And ventilation between the water-repellent material and metal coatings should also be built.

A cross-section of a cold roofing cake for metal tiles looks like this:

Rafter legs, the cross-section of which is calculated without taking into account the weight of the insulation and related components.
A waterproofing layer laid over the rafters.
Lathing designed to provide a ventilation gap, fix waterproofing and fasten sheets of metal tiles.

The sheathing for both types of rafter systems is laid in a special way. The step of its installation is determined by the distance between adjacent transverse steps of the metal tile sheet. The distance depends on the brand of roofing, on average it is 300, 350 and 400mm.

The dimensions of the starting lath should be different from the subsequent ordinary bars. For example, if all ordinary laths are made of a block with a cross-section of 30x50mm, then to make the very first element from the eaves line you need to take a block of 50x50mm. The distance between the starting block and the cornice line is always less than the step between the row laths. So it is necessary that the first transverse step of the sheet lies exactly on the base.

The procedure for laying metal tiles on a gable roof

In the vast majority of cases, when repairing a roof, the choice falls on metal tiles.

In addition to a long list of economic and operational benefits, this material is also interesting because it is suitable for self-installation.

In this case, even the basic skills of a home craftsman will be enough to ensure that the roof is not only durable and practical, but also attractive in appearance.

Advantages of metal tiles

The widespread use of metal tiles is due to the combination of the following advantages in this type of roofing material:

Compared to most other roofing coverings, metal tiles have a relatively low cost.

What makes purchasing such a roof even more profitable is the ability to avoid hiring builders to install it, as well as its long service life.

Light weight.

With an average weight of 1 sq. m of material is about 6 kg, the total mass of the roof is relatively small. This allows you to do without the use of a powerful and expensive rafter system. Besides, light roof does not require the installation of continuous sheathing, which simplifies the calculation of the roof and reduces the cost of work.

Resistance against external factors. Protection is provided by the use of several security words in the design of the roofing sheet. Therefore, the metal base of the canvas is not afraid of prolonged exposure to moisture, direct sunlight, or damage during installation or hail.
Aesthetics. The production technology of metal tiles allows you to create absolutely any texture. Accordingly, on the market you can easily choose an option suitable for the overall exterior of the building. The range is further expanded by the possibility of painting sheets in all shades of the palette.
Fire safety. The basis of the metal tile is a sheet of galvanized steel. This material is completely non-flammable, making it absolutely fireproof.

The indicated advantages of metal roofing make it the most practical, affordable and attractive externally a roofing option.

Materials and tools

To install metal tile sheets you will need a kit traditional instruments for finishing work:

electric screwdriver;
jigsaw or circular saw;
marker;
construction stapler with staples;
metal scissors;
scotch;
laser plane builder or construction level;
roulette.

Of the materials, in addition to the metal tile itself and its accessories, you will need the following:

bars 50 x 50 mm;
boards 100 wide and 25–35 mm thick;
sheet waterproofing material;
wooden slats;
galvanized screws, nails.

You will also need personal protective equipment and auxiliary equipment: a ladder, scaffolding, a brush for sweeping away debris, etc.

Structure of the roofing “pie”

The basis for creating a roof made of metal tiles is rafter system. In a gable (or gable, as it is more often called in everyday life) roof, the rafter system has the most convenient configuration for installation work, since it forms only two planes.

A layer of waterproofing material (3) is laid on top of the rafter system. Without it, moisture condensing on a metal roofing sheet will be absorbed into the wooden structures under the roof, destroying them. Waterproofing also helps in cases where the roof begins to leak.

Vertical slats - counter-lattice (4) - are attached to the waterproofing material along the rafters. Their purpose is to organize a ventilated space between the waterproofing and the sheathing.

In addition, the roof structure contains frontal boards (8) and eaves strips (10). The first ones are stuffed onto the end part of the rafters (1) and protect from moisture falling with the wind. The latter serve to remove moisture flowing down the waterproofing layer.

Installation procedure

On gable roofs metal tiles are laid first on one slope, and then on the other.

Laying sheets of metal tiles should begin with lower slope angle.

All installation work on roofing is carried out in several stages:

Checking the geometry of load-bearing roof elements

At this stage, the diagonals of the roof slopes are measured and compared using a tape measure. If they coincide, then the roof has a rectangular shape suitable for laying metal tiles.

In addition, you need to use a level or builder to make sure that the ridge and both cornices are strictly horizontal. The flatness of the slopes must also be checked. Emergency sections of the rafter system are being repaired.

Installation of the frontal board and filing of the roof overhang

The place where the front board is attached (8) is the end (bottom) part of the rafters (1). This roofing element is fixed with galvanized nails.

Front boards should not completely isolate the under-roof space from the street. To ensure free passage of air, ventilation gaps must remain between them.

WITH reverse side of the frontal board, a horizontal filing is installed under the roof overhang. As such, you can use perforated plastic panels. This option is convenient because it allows you to use fastening j-straps for plastic, nailed to the front board from behind. If boards are used, ventilation slots should be left between them.

Installation of gutter hooks

Hooks(9) should be placed in a straight line with a slope towards the planned drainage. Reliable drainage will be ensured by the slope angle from 5 mm per meter of gutter.

The most practical and easy to install are hooks of extended length. They are sewn to the bottom of the rafters on top of the front board. To ensure the vertical position of the hook, grooves of the required depth are cut in the board and the bottom of the rafters.

First of all, the upper part of the hook is nailed or screwed to the top of the rafters. Then it is bent to the required position and fixed on the end of the rafters. If the drainage system is installed after laying the metal tiles, then short hooks are used, the upper part of which does not go under the roofing.

Laying waterproofing material

Rolled water-repellent materials (films) are used for the roofing “pie”. As it moves onto the rafters, the roll unfolds horizontally along the eaves. You should start from the bottom of the roof. Each subsequent strip is laid with an overlap on the bottom one. The amount of overlap is 15 cm.

The waterproofing sheets (3) should be fixed with a construction stapler. The material is allowed to sag up to 2 cm. The joints are taped with tape. The top and bottom of the film are determined by the factory markers applied to it.

Along the rafters on top of the waterproofing they are stuffed vertical(4) and horizontal(6) battens made of wooden planks. They are nailed along the central part of the rafter beams.

Installation of sheathing

The bars or boards of the horizontal sheathing begin to be packed from below, from the eaves. The first beam of the sheathing must have a cross-section larger than the cross-section of the remaining beams. When installing it, it is necessary to control strict parallelism to the cornice. Installation of metal tile sheets begins with fixation on the lower beam of the sheathing. Therefore, the appearance of the entire roof will largely depend on the accuracy of its installation.

The pitch of the sheathing beams depends on the distance between the horizontal waves on the metal tile sheet and must coincide with it. Most often the pitch is 300, 350 or 400 mm. The only exception is the step up to the second beam of the sheathing. Here it should be reduced by 70 mm.

The most top bars the battens are also stuffed with decrease step, right up to nailing the beams tightly. This will facilitate the installation of ridge elements and add strength the entire structure. Around roof and dormer windows, chimneys, ventilation ducts and other additional elements(bridges, snow guards, etc.) the sheathing should also be strengthened by stuffing a continuous web of beams.

Installation of curtain rods

The planks are attached along the entire cornice using galvanized self-tapping screws. The fastening pitch is 300 mm. If the length of one bar is not enough, then it is increased. In this case, the planks are laid overlapping with overlaps of 50–100 mm.

The eaves strip is attached with a slight tension, then the roofing material will be more resistant to gusts of wind and less noisy.

Installation of the lower valley

Where the roof planes (for example, the slope of the roof of a house and the slope of the roof dormer window) form intersections at a slight angle; installation of a special strip is required - the lower valley (20b).

A continuous plank sheathing (7) is placed under it. Boards with a cross section of 150 x 25 mm are applied as lathing material.

Under the lower valley you will need a continuous strip of sheathing about 300 mm wide.

The position of the lower valley is selected so that its edge in the overhang area passes over the cornice board. The sheet of metal tiles and the lower valley strip are not directly fastened together, but are laid with porous insulation.

Installing a chimney outlet bypass

For a brick chimney pipe, the procedure will be as follows:

A layer of waterproofing is applied around the perimeter with an overlap of 50 mm on the pipe. For fixation, you can use heat-resistant tape;
bypass strips (28) are installed;
A groove about 15 mm deep is cut along the pipe, into which the upper edges of the bypass strip are inserted. You can only tap on solid bricks; it is prohibited to do this on masonry joints;
The drainage bar organizes the drainage of water, which either drains into the nearest valley or is directed to the eaves.

The decorative pipe surround is not installed at this stage of the work; metal tiles are laid first. For round chimneys, the lining is made of sealing tape. To ensure a tight fit to the pipe, the tape will need to be cut along the top edge in several places before gluing.

Installation of metal tile sheets

If it is possible to lay sheets along the entire roof slope in one row, the installation order will be as follows:

the outermost sheet is applied and its position is verified relative to the eaves and side section of the roof;
the first sheet is fixed in the upper part with one self-tapping screw;
the next sheet is laid with an overlap in the wave and aligned vertically;
the sheets are sewn together with self-tapping screws, but the threads should not be screwed into the beams;
the following sheets are mounted in the same way;
the resulting assembly is once again verified relative to the ridge and cornice;
The screws are screwed into the sheathing.

If the height of the sheet is less than the length of the slope and you have to lay the metal tiles in several rows, the procedure will be as follows:

the first two sheets are laid according to the same pattern as for single-row installation;
the third sheet is placed on top of the first with a horizontal offset of 150 mm, after which these two sheets are fastened together;
the next sheet is placed above the second and attached to it horizontally. With the third sheet, fastening is carried out on the vertical side;
four fastened sheets are aligned together and, by tightening the screws, fixed to the sheathing.

At the final stage fixation produced at the bottom of each wave by bottom cut sheets. In places where vertical overlap, screws are screwed into crest waves. Distance between self-tapping screws should be chosen with this calculation: there should be 6–8 pieces per square meter.

Dormer window device (“cuckoo”)

The location of the "cuckoo" is determined early. When laying sheets of metal tiles, areas corresponding to configurations dormer window.

Roofing pie under the window neatly sawed out. By perimeter windows are being installed additional sheathing beams.

Gaps between the timber and the sheet of metal tiles are sealed. To drain water, install valleys the top and bottom of the dormer window.

Installing the end strip

The purpose of this slats(29) – protection from precipitation and sharp gusts of wind penetrating under the metal tiles. In addition, the end strip also performs decorative function: when installed correctly, its upper edge overlaps crest waves of metal tiles. Screw The end strip starts from the side of the cornice. If it is necessary to build up, provide an overlap in 100 mm.

Installation of the upper valley

The purpose of this element is to drain water, in addition, upper valley(20a) makes roof joints more aesthetically pleasing.

For installation, use self-tapping screws, screwing them in so that don't disturb waterproofing layer. Between the upper valley panel and the surface of the metal tile, a self-expanding insulation.

Installation of junction strips

These planks allow you to organize careful And sealed transition from the roof surface to adjacent walls and other structural elements of the building and roof.

The connection to the wall is arranged according to the same principle as the connection to the chimney.

Installation of ridge strips and external corners

Before installation ridge strip you should make sure that the gap between the waterproofing sheets of adjacent roof slopes is not less than 20 cm. On top of the top continuous sheathing you can lay additional a layer of waterproofing material in a strip of 150 mm.

The ridge is fastened with self-tapping screws screwed into sheathing through the covering wave. To increase the ridge strip, organized overlaps, serving as additional ribs rigidity.

End parts of the ridge are closed with external corners fixed with self-tapping screws. Between the metal tile and the ridge strip is laid insulation made of elastic material.

Installation of stairs, walkway, roof railing and snow guard

Roofing accessories made of metal tiles are mounted on top of the roofing.

Their places placement are determined in advance and are intensifying additional beams and sheathing boards.

Particular attention is paid to installation snow guard(21). It is fixed to the rafters complete reinforced screws.

Installation of a drainage system

When installing water drainage systems The following rules should be followed from the roof:

to one drain pipe it is forbidden install more than 10 meters of drainage gutter;
Part gutters above the funnel should be cut at an angle with sides in 100–110 mm;
funnel should be located under the gutter at a distance of 150 mm.

All elements of the drainage system, including plugs, funnels, etc., have a fixation system among themselves. However, after installation work is completed, they should be further processed. silicone sealant.

Roof grounding with a separate bus

Since metal tiles have the ability to conduct electricity, then for safety reasons it should be provided with a system grounding.

Grounding is done by connecting electrical wires large section with one end to the roof (through a self-tapping screw). The second end is securely attached to metal structure buried in the ground depth at least a meter.

Post-installation processing

Metal tiles require periodic inspection(semiannually). From the roof and drainage system clean up debris and leaves, and the surface cleanse with a soft brush.

Canvas in problem areas Can tint, this will increase its corrosion resistance.

Installing counter battens under the rafters

The system of counter-battens under the rafters allows you to insulation roofs. They are used as counter rails wooden beams or planks nailed.

Laying vapor barrier and fastening with slats

Leave insulation open is unacceptable, since moisture can get on it and negate the entire insulating effect. To prevent this, apply to the insulation vapor barrier film(16). This material does not allow moisture to pass through, but effectively allows water vapor to pass through, leaving the insulation dry

Wooden slats are placed on top of the vapor barrier for fixing whole pie.

How to build a garage with a gable roof with your own hands, read in this article.

Safety precautions

Work on installing the roof of gable roofs refers to work with high level of danger, and the more slope stingrays, the stricter the safety requirements. Don't neglect them, take care of yours health:

be sure to wear safety belt, tied with a strong rope to a strong part of the building;
work in shoes that have good clutch with surface;
stairs And forests securely fasten to the walls of the house;
roof protect scaffolding, scaffolding, mesh or sides with a height of at least 1 m.

When working with metal tiles the following rules should be adhered to:

always use mittens;
to not allow applying excessive force to metal;
take into account the strength of the wind and windage sheets of metal tiles.

In addition, it will not be superfluous to use all available devices that make work easier. Eg, inclined guides from long boards will not only increase safety when rise sheets, but will also ensure the safety of the material.

In general, installation of metal tiles on gable roof does not pose a serious problem. It is enough to follow safety rules and follow all recommendations to get reliable And beautiful roofing at the lowest possible cost.

The procedure for laying metal tiles on a gable roof: how to install it correctly with your own hands, technology step by step, video

In the vast majority of cases, when repairing a gable roof, the choice falls on metal tiles. In addition to the long list of economic and operational advantages, this material is also interesting for its suitability for self-installation.

When carrying out installation work, it is very important to correctly determine the pitch of the rafters for the metal tiles. It is important to understand that making such calculations is quite difficult and the level of strength of the roof directly depends on how correctly everything is done. Many experts argue that the service life of not only the roof, but also the structure itself depends on the level of reliability of fastening the metal tiles to the rafters. Due to the fact that metal tiles have quite a lot of weight, the rafter system must be strong. In addition, beginners will not be able to lay roofing material. In order to carry out installation work correctly, it is recommended to take a responsible approach to calculating the pitch of the rafter system.

Construction of a rafter system for metal tiles

Making a rafter system for metal tiles with your own hands is not as difficult as making the appropriate calculations. It is important to understand that the type of system used depends entirely on the type of roof. Today, the most popular option is the rafter system for a gable roof under metal tiles. Such rafter systems, as practice shows, are excellent for installing metal tiles on the roof of a residential building. For arranging rafters they use wooden blocks different lengths - the choice, as a rule, directly depends on the length of the legs. Many experts recommend paying attention to the fact that it is necessary to choose the right angle of inclination, which can vary from 15 to 30 degrees - this value is considered optimal.

Calculation of the distance between rafters for metal tiles

The pitch of the rafters for metal tiles is the distance from one rafter leg to the other; to put it differently, roofers call this distance the pitch of the rafter system. This distance directly depends on the type of roofing chosen. As practice shows, for all roofing materials, including metal tiles, this size varies from 0.6 to 1.2 m. However, it is important to understand that it is best to carry out accurate calculations of the distance for each material separately - there must be individual approach.

Before starting installation work, it is necessary not only to determine the distance between the rafters, but also to understand how much material will be required for the legs. To find out the pitch of the rafters of a gable roof under metal tiles or a pitched roof, it is recommended to adhere to the following recommendations:

The first step is to calculate the length of the metal roof slope. Measurements are usually taken along the roof eaves.
After this, it is possible to select an arbitrary step. It is important to take into account the fact that the pitch limits for metal tiles can vary from 0.6 to 1 m. For example, initially it became necessary to maintain a distance of 0.8 m. The length of the slope should be divided by the selected value for the pitch of the rafter system. Let's assume that the length of the slope is 12 m, it turns out that 12/0.8 and the result is 15. After this, you will need to add 1 to the resulting value. In the case when the number turns out to be fractional, then it should definitely be rounded up. Thus, it turns out 15+1=16. This value shows exactly how many rafter legs should be installed on the roof. Then you will need to take the length of the slope and divide it by the resulting number of legs. It turns out that 12/16 and it turns out to be 0.75 m.

Many experts recommend entrusting this work to professionals, which will allow you to get the desired result in the future. It is important to understand that there is a high probability that mistakes will be made, which will ultimately negatively impact the finished roof structure.

Attention! As practice shows, such calculations can be used for any roofing materials.

Installation of rafters under metal tiles

Since installation work is carried out at a high altitude, if necessary, you can assemble the frame for the load-bearing rafter system on the ground, then lift it and fix it on the roof. For these purposes, it is best to create a special template or diagram of the rafter system for metal tiles made from boards, according to which installation will be carried out.

The whole process is carried out in stages:

First of all, the boards are lifted above the wall of the building, leveled and fixed with nails.
According to the project, the boards must be aligned at a certain angle of inclination, after which all elements are securely fixed.
Ultimately, a structure should be obtained that resembles a rafter system in appearance and shape. Manufacturing must be carried out taking into account the calculations made.
Then you need to lower the template to the ground and install all the finishing elements.

You should also not forget about the installation of supporting elements, namely the Mauerlat. Laying is carried out on load-bearing walls in a longitudinal position. Special pins or wire rods are used as fastening elements.

The next step is the installation of the ridge girder, which is used as a supporting part for all roofing. For the work you will need to use timber or a hewn log. In cases where the length of the slope does not exceed 6 m, you can do without additional supporting elements.

When the installation of all elements has come to an end, you can begin installation and further installation work on arranging the rafter system according to the attached template.

The Mauerlat can be secured in several ways:

rigid connection- V in this case beams or corners should be used, nails and staples are used much less often; a special feature is the fact that it will be necessary to additionally tie the rafters to the wall, using anchors for these purposes;
sliding method– in such cases, a hinged connection must be created; it can be achieved by joining the elements with cuts.

During operation, the pitch distance of the rafter system must be observed.

When choosing a rafter pitch for metal tiles, it is worth paying attention that the distance should not be less than the minimum permissible value and greater than the maximum permissible value, that is, it can vary from 0.6 m to 1.2 m.

If it was decided to choose a distance from 0.6 to 1 m, then the length of the rafters in this case should not be more than 6 m. In the event that it is reduced, it is allowed to make a spread of up to 1.2 m.

If the legs of the rafter system are installed more often than every 0.6 m, this will only contribute to a significant weighting of the roof and, as a rule, an increase in costs. If necessary, the distance can be 1.2 m, but it is important to understand that in this case the level bearing capacity will be significantly reduced, which will negatively affect metal tile structures.

If necessary, you can increase the level of strength, but for this you will need to make a continuous sheathing of wood boards. In such situations, the step can vary from 0.2 to 0.3 m. This option is used extremely rarely, since its implementation requires much more investment.

An interval of 1.2 m is almost never used during installation work. This is due to the fact that despite the fairly high level of strength, the metal tiles will begin to sag under the weight of snow in winter period time or during strong gusts of wind.

The cross-section of the timber used for arranging the rafter system is also important. It depends on him what distance will be chosen. The best option The choice of wooden blocks with a cross-section of 150 * 150 mm is considered, while the sheathing can be installed at intervals of 4 to 7 cm. In this case, it is recommended to take into account the step of the transverse wave.

Conclusion

The pitch of the rafters for metal tiles can only be determined after the appropriate calculations have been made. It is important to understand that if the distance is quite small, this can significantly increase the consumption of material and the project budget, and if the distance is made too large, then during operation the roofing material will begin to sag, which will lead to deformation of the metal tile.

A gable roof or gable roof is a roof with two slopes, i.e. having 2 inclined surfaces (slopes) of a rectangular shape.

Gable roof frame in effect design features ideally combines simplicity of design and maintenance with reliability and durability. These and many other parameters make the construction of a gable roof a practical and rational solution for private and commercial housing construction.

In this article, we will look at how to make a rafter system for a gable roof with your own hands. For effective perception of the material, it is presented in the form of step-by-step instructions from A to Z, from selection and calculations, to installation of the Mauerlat and sheathing under the roof. Each stage is accompanied by tables, diagrams, drawings, drawings and photos.

The popularity of the house roof is due to a number of advantages:

design variability;
simplicity in calculations;
naturalness of water flow;
integrity of the structure reduces the likelihood of leaks;
efficiency;
preserving the usable area of the attic or the possibility of arranging an attic;
high maintainability;
strength and wear resistance.

Types of gable roof

The installation of a gable roof truss system depends, first of all, on its design.

There are several options for gable roofs (types, types):

The most common roof installation option due to its simplicity and reliability. Thanks to symmetry, a uniform distribution of loads on the load-bearing walls and mauerlat is achieved. The type and thickness of the insulation does not affect the choice of material.

The cross-section of the beam makes it possible to provide a reserve of bearing capacity. There is no possibility of rafters bending. Supports and struts can be placed almost anywhere.

An obvious drawback is the impossibility of arranging a full-fledged attic floor. Due to sharp corners, “dead” zones appear that are unsuitable for use.

The arrangement of one angle of more than 45° leads to a reduction in the amount of unused area. There is an opportunity to do living rooms under the roof. At the same time, the requirements for calculations increase, because the load on the walls and foundation will be distributed unevenly.

This roof design allows you to equip a full second floor under the roof.

Naturally, a simple gable rafter roof differs from a broken roof, not only visually. The main difficulty lies in the complexity of the calculations.

Design of a gable roof truss system

Building a roof of any complexity with your own hands requires knowledge of the purpose of the main structural elements.

The locations of the elements are shown in the photo.

Mauerlat. Designed to distribute the load from the rafter system onto the load-bearing walls of the building. To arrange the Mauerlat, a timber made of durable wood is selected. Preferably larch, pine, oak. The cross-section of the timber depends on its type - solid or glued, as well as on the expected age of the structure. The most popular sizes are 100x100, 150x150 mm.
Advice. For a metal rafter system, the Mauerlat must also be metal. For example, a channel or an I-profile.

Rafter leg. The main element of the system. To make rafter legs, a strong beam or log is used. The legs connected at the top form a truss.

The silhouette of the roof truss determines the appearance of the structure. Examples of farms in the photo.

The parameters of the rafters are important. They will be discussed below.

Puff- connects the rafter legs and gives them rigidity.

Run:

Ridge run, is mounted at the junction of one rafter to another. In the future, the roof ridge will be installed on it.

Side purlins, they provide the truss with additional rigidity. Their number and size depend on the load on the system.

Rafter stand- vertically located beam. It also takes on part of the load from the weight of the roof. In a simple gable roof it is usually located in the center. With a significant span width - in the center and on the sides. In an asymmetrical gable roof, the installation location depends on the length of the rafters. If there is a broken roof and one room is arranged in the attic, the racks are located on the sides, leaving free space for movement. If there are supposed to be two rooms, the racks are located in the center and on the sides.

The location of the rack depending on the length of the roof is shown in the figure.

Strut. Serves as a support for the stand.

Advice. Installing the brace at an angle of 45° significantly reduces the risk of deformation from wind and snow loads.

In regions with significant wind and snow loads, not only longitudinal struts are installed (located in the same plane as the rafter pair), but also diagonal ones.

Sill. Its purpose is to serve as a support for the rack and a place for attaching the strut.

Lathing. Designed for movement during construction work and fixation of roofing material. Installed perpendicular to the rafter legs.

Advice. An important purpose of the sheathing is to redistribute the load from the roofing material to the rafter system.

Having a drawing and diagram indicating the location of all the listed structural elements will help in the work.

Advice. Be sure to add information about the passage of the ventilation shaft and chimney to the gable roof rafter system diagram.

The technology of their installation is determined by the type of roof.

Selection of material for rafters

When calculating the material for a gable roof, you need to choose high-quality wood without damage or wormholes. The presence of knots for beams, mauerlat and rafters is not allowed.

For sheathing boards, there should be a minimum of knots, and they should not fall out. The wood must be durable and treated with the necessary preparations that will increase its properties.

Advice. The length of the knot should not exceed 1/3 of the thickness of the timber.

Calculation of the rafter system of a gable roof

Calculating the material parameters is an important step, so we present the calculation algorithm step by step.

It is important to know: the entire rafter system consists of many triangles, as the most rigid element. In turn, if the slopes have different shapes, i.e. are an irregular rectangle, then you need to divide it into separate components and calculate the load and amount of materials for each. After calculations, summarize the data.

1. Calculation of the load on the rafter system

The load on the rafters can be of three types:

Constant loads. Their action will always be felt by the rafter system. Such loads include the weight of the roof, sheathing, insulation, films, additional roofing elements, finishing materials for. The weight of the roof is the sum of the weight of all its constituent elements; such a load is easier to take into account. On average, the constant load on the rafters is 40-45 kg/sq.m.

Advice. To make a safety margin for the rafter system, it is better to add 10% to the calculation.

For reference: The weight of some roofing materials per 1 sq.m. presented in the table

Advice. It is desirable that the weight of roofing material per 1 sq.m. roof area did not exceed 50 kg.

Variable loads. They act at different times and with different strengths. Such loads include: wind load and its strength, snow load, precipitation intensity.

In essence, the roof slope is like a sail and, if you take into account the wind load, the entire roof structure can be destroyed.

The calculation is carried out according to the formula: wind load is equal to the regional indicator multiplied by the correction factor. These indicators are contained in SNiP “Loads and Impacts” and are determined not only by the region, but also by the location of the house. For example, a private house surrounded by multi-story buildings experiences less load. Standing separately Vacation home or the cottage experiences increased wind loads.

2. Calculation of snow load on the roof

The roof calculation for snow load is carried out according to the formula:

Full snow load equal to the weight of the snow multiplied by the correction factor. The coefficient takes into account wind pressure and aerodynamic influence.

The weight of snow that falls on 1 square meter. roof area (according to SNiP 2.01.07-85) is in the range of 80-320 kg/sq.m.

Coefficients showing the dependence on the slope angle are shown in the photo.

Nuance. When the slope angle is over 60 ° the snow load does not affect the calculation. Because the snow will quickly slide down and will not affect the strength of the beam.

Special loads. Accounting for such loads is carried out in places with high seismic activity, tornadoes, and storm winds. For our latitudes, it is enough to make a safety margin.

Nuance. The simultaneous action of many factors causes a synergy effect. This is worth considering (see photo).

Assessment of the condition and load-bearing capacity of walls and foundations

It should be borne in mind that the roof has significant weight, which can cause damage to the rest of the building.

Determining the roof configuration:

simple symmetrical;
simple asymmetrical;
broken line

How more complex form roof, the greater the number of trusses and sub-rafter elements needed to create the necessary safety margin.

The angle of inclination of a gable roof is determined primarily by the roofing material. After all, each of them puts forward their own demands.

soft roof - 5-20°;
metal tiles, slate, corrugated sheets, ondulin - 20-45°.

It should be noted that increasing the angle increases the area of space under the roof, but also the amount of material. What affects the total cost of work.

Nuance. Minimum angle The slope of the gable roof should be at least 5°.

5. Calculation of rafter pitch

The pitch of the gable roof rafters for residential buildings can range from 60 to 100 cm. The choice depends on the roofing material and the weight of the roof structure. Then the number of rafter legs is calculated by dividing the length of the slope by the distance between the rafter pairs plus 1. The resulting number determines the number of legs per slope. For the second, the number must be multiplied by 2.

Rafter length for attic roof calculated using the Pythagorean theorem.

Parameter "a"(roof height) is set independently. Its value determines the possibility of arranging a living space under the roof, the convenience of being in the attic, and the consumption of material for the construction of the roof.

Parameter "b" equal to half the width of the building.

Parameter "c" represents the hypotenuse of the triangle.

Advice. To the obtained value you need to add 60-70 cm for cutting and moving the rafter leg beyond the wall.

It is worth noting that maximum length timber - 6 m.p. Therefore, if necessary, the timber for the rafters can be spliced (extension, joining, joining).

The method of splicing rafters along the length is shown in the photo.

The width of the roof rafters depends on the distance between opposite load-bearing walls.

7. Calculation of the rafter cross-section

The cross-section of the rafters of a gable roof depends on several factors:

loads, we have already written about it;

type of material used. For example, a log can withstand one load, timber - another, laminated timber - a third;

rafter leg lengths;

the type of wood used in construction;

distances between rafters (rafter pitch).

You can determine the cross-section of the beam for the rafters, knowing the distance between the rafters and the length of the rafters using the data below.

Rafter cross-section - table

Advice. How more step installation of rafters, the greater the load on one rafter pair. This means that the cross-section of the rafters needs to be increased.

Dimensions of lumber (timbers and boards) for a gable rafter system:

thickness (section) of the Mauerlat - 10x10 or 15x15 cm;

the thickness of the rafter leg and tie is 10x15 or 10x20 cm. Sometimes a beam of 5x15 or 5x20 cm is used;

run and strut - 5x15 or 5x20. Depending on the width of the foot;

stand - 10x10 or 10x15;

bench - 5x10 or 5x15 (depending on the width of the rack);

thickness (section) of the roof sheathing - 2x10, 2.5x15 (depending on the roofing material).

Types of gable roof rafter system

For the roof structure under consideration, there are 2 options: layered and hanging rafters.

Let's consider each type in detail in order to make an informed choice.

Hanging rafters

They are used for roof widths of no more than 6 lm. Installation of hanging rafters is carried out by attaching the legs to the load-bearing wall and the ridge girder. The design of hanging rafters is special in that the rafter legs are under the influence of a bursting force. Hanging rafters with a tie installed between the legs reduce its impact. The tie in the rafter system can be wooden or metal. Often the ties are placed at the bottom, then they play the role of load-bearing beams. It is important to ensure that the tie is securely attached to the rafter leg. Because a bursting force is also transmitted to it.

Advice.
The higher the tightening is located, the greater strength it should have.
If the tightening is not installed, the load-bearing walls may simply “move apart” from the pressure created by the rafter system.

Layered rafters

They are used for arranging roofs of any size. The design of layered rafters provides for the presence of a beam and a stand. The bench lying parallel to the Mauerlat takes on part of the load. Thus, the rafter legs are, as it were, inclined towards each other and supported by a stand. The rafter legs of the layered system work only in bending. And the ease of installation also tips the scales in their favor. The only drawback is the presence of a stand.

Combined

Due to the fact that modern roofs are distinguished by a wide variety of shapes and complexity of configurations, a combined type of rafter system is used.

After choosing the type of rafter system, you can accurately calculate the amount of materials. Write down the calculation results. At the same time, professionals recommend drawing up drawings for each roof element.

Installation of a gable roof rafter system

After the gable roof rafters have been calculated, installation can begin. We will divide the process into stages and give a description of each of them. The result will be a kind of step-by-step instructions containing additional information on each stage.

1. Attaching the Mauerlat to the wall

The beam is installed along the length of the wall on which the rafters will rest.

In log houses, the role of the mauerlat is played by the upper crown. In buildings built from porous material (aerated concrete, foam concrete) or brick, the Mauerlat is installed along the entire length of the load-bearing wall. In other cases, it can be installed between the rafter legs.

Material prepared for the website www.site

Since the length of the Mauerlat exceeds the standard dimensions of lumber, it has to be spliced.

The connection of the Mauerlat to each other is done as shown in the figure.

How to connect the Mauerlat?

The beams are cut only at an angle of 90°. Connections are made using bolts. Nails, wire, wooden dowels are not used.

How to attach the Mauerlat?

The Mauerlat is installed at the top of the wall. The installation technology provides several ways to attach the Mauerlat:

strictly in the center of the load-bearing wall;
with a shift to one side.

Advice.
The Mauerlat cannot be placed closer than 5 cm to the outer edge of the wall.

To protect the timber for the Mauerlat from damage, it is laid on a layer of waterproofing material, which most often is ordinary roofing felt.

The reliability of the Mauerlat fastening is an important aspect of construction. This is due to the fact that the roof slope is like a sail. That is, it experiences strong wind load. Therefore, the Mauerlat must be firmly fixed to the wall.

Methods for attaching the Mauerlat to the wall and rafters

Anchor bolts. Ideal for monolithic structures.

Wooden dowels. Used for log houses and beams. But, they are always used with additional fasteners.

Staples.

Stud or fittings. It is used if the cottage is built from porous materials (aerated concrete, foam concrete).

Sliding mount (hinge). Tying in this way allows for the displacement of the rafter legs when the house shrinks.

Annealed wire (knitting, steel). Used as an additional mount in most cases.

2. Manufacturing of trusses or pairs

Installation is carried out in two ways:

installation of beams directly on the roof. It is not used often, since it is problematic to carry out all the work, measurements, and trimming at height. But it allows you to completely do the installation yourself;

assembly on the ground. Those., individual elements(triangles or pairs) for the rafter system can be assembled at the bottom and then raised to the roof. The advantage of such a system is faster performance of high-altitude work. The disadvantage is that the weight assembled structure roof truss can be significant. To lift it you will need special equipment.

Advice. Before assembling the rafter legs, you need to apply markings. It is very convenient to use templates for these purposes. The rafter pairs assembled according to the template will be absolutely identical. To make a template, you need to take two boards, the length of each of which is equal to the length of one rafter, and connect them together.

3. Installation of rafter legs

The assembled pairs rise to the top and are installed on the Mauerlat. To do this, you need to make a gash at the bottom of the rafter legs.

Advice. Since the slots on the Mauerlat will weaken it, you can only make cuts on the rafter leg. To ensure that the cut is uniform and fits tightly to the base, you need to use a template. It is cut out of plywood.

Methods of fastening the rafter leg are shown in the figure.

You need to start installing rafter pairs from opposite ends of the roof.

Advice. To correctly install the rafter legs, it is better to use temporary struts and spacers.

A string is stretched between the fixed pairs. It will simplify the installation of subsequent rafter pairs. It will also indicate the level of the ridge.

If the rafter system is mounted directly on the roof of the house, then after installing the two outer rafter legs, the ridge support is installed. Next, the halves of the rafter pair are attached to it.

It is worth noting that the opinions of professionals differ on this issue. Some advise using a staggered fastening pattern, which will allow the increasing load to be distributed more evenly on the walls and foundation. This order involves installing one rafter in a checkerboard pattern. After part of the rafter legs is installed, the missing parts of the pair are mounted. Others insist that it is necessary to mount each pair in a sequential manner. Depending on the size of the structure and the configuration of the truss, the rafter legs are reinforced with supports and racks.

Nuance. Additional structural elements are connected using cutting. It is preferable to fix them with construction staples.

If necessary, you can lengthen the rafter leg.

Methods for splicing rafter legs are shown in the photo.

Advice. The method by which the mauerlat is lengthened (cut at 90°) cannot be used in this case. This will weaken the rafter.

4. Installing the ridge of a gable roof

The roof ridge unit is made by connecting the rafter legs at the top.

Roof ridge structure:

Method without using a support beam (see figure).

Method using rafter beams. Timber is needed for large roofs. In the future, it can become a support for the rack.

Method of laying on timber.

A more modern version of making a ridge knot can be considered the method shown in the photo.

Cutting method.

After the rafter system is installed, we perform major fastening of all structural elements.

5. Installation of roof sheathing

The sheathing is installed in any case, and is designed for more convenient movement along the roof during work, as well as for fastening roofing material.

The sheathing pitch depends on the type of roofing material, for example:

for metal tiles - 350 mm (the distance between the two lower boards of the sheathing should be 300 mm).
for corrugated sheets and slate - 440 mm.
under soft roof We lay a continuous sheathing.

Rafter system of a gable roof with an attic - video:

Conclusion

As you can see, despite its apparent simplicity, the installation of a gable roof rafter system contains many pitfalls. But, based on the recommendations given, you can easily build a reliable structure with your own hands.

Rafter system under metal tiles is one of the most economical designs modern roofs. This is due to the low weight of the steel profile sheets of the coating and the absence of solid bases such as OSB or plywood. Process correct installation A lot of literature, instructions, and videos are devoted to roofing elements. The process of choosing a rafter system for an individual developer is less clear. This article makes an attempt to inform the average reader how to choose the right rafters for metal tiles.

The design of the rafter system depends on the shape of the roof, the shape and size of the building. There are two main design diagrams rafter systems: Layered rafters are a simple and reliable non-expanding rafter system in which rafter beams rest (lean) at the top and bottom on walls or beam elements. This rafter system is most popular in individual construction. The layered system consists of rafter legs resting on the mauerlat below and on the girder at the top, racks resting on beds and linings, as well as struts, struts and trusses. Hanging rafters are a more complex system, used in the absence of internal walls, as a rule, with large distances between supports. This design is a spacer design, in which the expansion force is damped by tightening. The structural elements of the system are various types of roof trusses. The advantage of this system is that all elements can be manufactured and assembled either on site or in a factory. In the latter case, all that remains is to complete the larger assembly and installation. The use of such a system is justified for projects with short construction periods.
Another advantage is that finished elements, as a rule, are subjected to fire-bioprotective impregnation in the factory. In addition, enterprises have big choice ready-made design solutions for different types roofs

Dimensions and sections of rafter system elements

Ideally, all elements of the house, including the roof, are developed in detail by the design organization. If there is no project or we are talking about reconstruction, then the following information will be useful.

For the manufacture of load-bearing structures For roofs, wood with a moisture content of no more than 25% should be used. The components can be made of logs, timber and edged boards.

Total massiveness of elements rafter roof depends on the distance between the load-bearing walls of the building, the climatic region of construction and the slope of the roof. The larger the span, the amount of snow and the heavier the roof structure, the more massive the supporting roof frame.

Geometry of layered rafters

Although the cross-section of almost all elements of the rafter system is calculated value, is defined in the construction literature minimum section rafter legs as 50×100 mm, Mauerlat 150×100 mm, and minimum height beds and spacers – 150 mm. It should be noted that the section of the rafters 50x100 mm looks like fireplace matches on the roof, and is often increased for visual comfort. Layered rafters work as bending elements and are calculated depending on the span of the building and the effective load.

So, among the known quantities there is the length of the roof, the span of the building (the distance between the supports C), the height of the roof, and, at a minimum, a general idea of the snow load. Among the unknowns there is the pitch of the rafters (B), the section of the rafters (a×b). Getting rid of the unknowns, we will assign the pitch of the rafters for the metal tiles. The rational distance varies between 0.6 and 1.2 m. If the roof has rafters made of logs, then the pitch of the rafters can be increased to 1.8 m. In a situation with metal tiles, this is not necessary, since you will have to make a thicker sheathing.

Rafter spacing from 0.6 to 0.9 m is mainly used for roofs with a cold attic and single rafters. It should be noted that the minimum pitch is rarely used, and installation is carried out in steps of at least 0.7 m. If an attic floor is not expected, any rafter pitch can be used for a cold attic. Sections of rafter legs for simple roofs with normal conditions in the climatic zone of central Russia can be preliminarily determined from the following table.

Roof slope, degrees	Rafter leg pitch, m	Board section
Roof slope, degrees	Rafter leg pitch, m	Distance between supports, m
20 - 30		3,0	3,5	4,0	4,5
	0,7	50×120	50×150	50×175	50×175
	0,9	50×150	50×175	50×175	50×200
	1,2	50×175	50×200	2×50×150	2×50×200

The cross-section of the sheathing with a rafter pitch of up to 0.7 m is recommended to be 25 × 50 mm; with an inter-rafter distance of 0.7 to 0.9 m, the size of the bars is 35 × 50 mm, and a rafter pitch of 0.9 m to 1.2 m requires sheathing sections 50×80 mm.

Mansard roof

With a mansard roof the situation is different. Since the time of all-Union unification and typification (experienced builders will understand), the modular dimensions of insulation boards have remained the same: sheet 600x1200 mm (TechnoNIKOL additionally produces insulation boards measuring 500x1000 mm). If you plan to place a living space in the attic space by making an attic roof, the option with maximum step rafters Moreover, with the insulation thickness starting from 150 mm and the need to make air gap 50 mm for ventilation of the under-roof space; a cross-sectional height of the rafter board of 200 mm is required. And with a more massive insulation layer (from 200 mm), which is not uncommon in our country, it is necessary to stuff even additional slats. Thus, if there is insulation between the rafters, a pitch of 1200 mm is taken from the condition of ease of installation of the insulation without additional trimming, the possibility of installation various types dormer windows and manufacturability of the ventilation device for the under-roof space. With a distance between the rafters of 1.2 m and a snow load for the 4th snow region and above (everything north of Sergiev Posad, St. Petersburg, the entire Volga region to Syzran, and further through the Ural ridge), the installation of paired rafter legs is required. The cross-sections of the elements can be preliminarily determined from the table below.

table 2

Roof slope, degrees	Rafter leg pitch, m	Section of the rafter leg
		Distance between supports, m
		3,0	3,5	4,0	4,5	5,0
20 - 25	1,2	2×50×150	2×50×175	2×50×175	2×50×200	2×50×200

You need to connect two boards through spacers with a pitch of no more than 1 meter. A rafter system made of paired boards is more reliable than a single system. And in order to sleep completely peacefully under a new roof, you need to contact the designers to calculate the roof elements. I recommend watching the following video:

The trend for the construction of gable roofs is growing not at all thanks to newfangled trends or the aesthetic appearance of such structures alone. Practical in practice and at the same time very attractive in terms of cost - these are the decisive criteria.

The rafter system of a gable roof can be made in many different forms. Freedom of choice also affected the issue of roofing materials. With proper calculations, such a frame can be used for all types of coatings. And to install metal tiles, known for their stability and low weight at low cost, you will need to take into account many important aspects.

In this article

Variability of execution

The right start would be to choose the very roof that will not only protect the owners from bad weather, but will also satisfy a number of other requirements:

Simple gable design – traditional version. Moreover, it is also found almost everywhere. Both roof slopes are symmetrical (located at the same angle to each other), due to which the load on the Mauerlat and load-bearing walls is distributed evenly. Deflection of the rafters is excluded in principle. On the other hand, the attic space under this structure is physically impossible to fully equip. The reason for this is the sharp corners that form the so-called. "dead" zones.
A simple asymmetrical gable roof - the slopes are located at different angles to each other. Usually one of them has a slope of more than 45 degrees, which gives much more possibilities for arranging the attic space. In addition, it is possible to make another slope of smaller dimensions by reducing the angle of inclination. If it is planned on the leeward side, then precipitation on such a surface will not linger long. Please note that designing this type of roof requires more complex calculations, because the load on the walls with the foundation will no longer be distributed evenly.
A broken gable is a rarely seen, but at the same time quite practical alternative. Its difference is that one slope is not smooth, but with an additional “kink” inward (at an obtuse angle). There is even more available space for arranging a room under the roof, but at the same time, the requirements for the design of the structure also increase.
A mansard gable roof is very close to a broken roof, but is distinguished by obtuse outward bends on both slopes at once.

Basics of the whole design

Regardless of the complexity of the layout, any structure of a gable roof truss system will consist of the following elements:

Mauerlat is a base that distributes the load from the rafters onto the load-bearing walls. This protects the building from deformation. It is a beam made of pine, oak or larch wood.

Rafters - form the slopes of the roof, being also its main load-bearing elements. You can use beams, logs and boards as rafters. The dimensions of the material are calculated based on the distance between the rafters, the load of the roofing and the amount of sediment in the region.

rafter leg

additional element

● Crossbar (tightening) - by installing this element between each pair of rafters, it “tightens” them in some way, giving them even greater rigidity. It can be mounted both in the lower part of the rafter legs, simultaneously becoming an attic floor beam, and in the upper part.

Puffs are especially in demand in hanging type rafter systems, which will be discussed below.

The ridge is the top of the roof. It represents the upper edges of the rafters, which are secured to each other by a purlin:

● These can be wooden or metal overlays, which are cut according to the angle between the rafters and are attached to them on both sides.

● A board mounted on an edge can also be used as a skate.

● Not only the board will do just as well, but also the overlays from the first option (they are also attached to both sides of the rafters).

Ridge purlin is a connecting link for rafter legs, which can consist of 1-2 boards or timber. Installed on racks.

Often, side purlins are installed in mansard roofs, which form a two-tier roof structure.

Racks are vertical support bars that support the frame. They give the entire structure rigidity and stability, taking part of the load from the walls. Depending on the layout of the room, the roofs are installed in different places of the attic floor (attic floor) or on a beam mounted on the beams:

Standard option

● Along the side edges of the attic – the rafters rest on the posts. Often used in broken gable structures.

● On the sides and in the center - for those cases when the span width is too large. Or if there is more than one room in the attic.

To avoid sagging of the rafter legs, struts are also installed on the racks. These are the same retaining elements mounted at the top of the racks at an angle of 45 degrees. Struts are primarily in demand for houses located in areas with snowy winters and hurricane winds.

Sheathing is the basis for installing the roofing covering, the load of which is evenly distributed over this element onto the roof frame. Fixed on the rafters (in a position perpendicular to them).
An overhang is a part of the roof protruding from the sides of a house. Protects the walls of the house from sedimentary moisture flowing from the roof.

The wood for a gable roof must be of the highest quality. It is fundamentally unacceptable to have knots on beams that will be used as rafters or mauerlat. However, for sheathing the requirements are slightly softer - a minimum of knots (if none of them exceed 1/3 of the thickness of the beam) will still not become an obstacle to operation. But at the same time they should not fall out of the wood.

Each block, board or log must be pre-treated with antiseptics to protect them from natural pests. In addition, these materials should be stored only in dry and well-ventilated areas. The wood should not be excessively damp at the time of installation, so as not to rot soon after installation.

Layered or hanging?

The most important criterion when calculating the rafter system of a gable roof is the walls of the house. Their location will determine which type of structure will be preferable.

Sloped roof - if the house has an internal load-bearing wall, then this option is the most suitable. In addition, the slanted structure is distinguished by its ease of installation and high level of reliability.
A wooden beam (wooden beam) is installed on the main internal walls. Racks are mounted on it, which support the ridge girder. The upper ends of the rafters are attached to the latter, after which the sheathing is mounted on the entire structure.
Hanging roof - when the layout of the house does not initially provide load-bearing walls inside, the rafter structure will rest on the side walls of the building. Important note: the distance between the latter should not exceed 7 meters, otherwise they will not be physically suitable for supporting the structure.

A mauerlat is mounted on two external load-bearing walls, on which the rafter legs (secured at the upper corners with a ridge purlin) rest. Installing ties between the rafters, reinforced by slopes, allows you to partially relieve the bursting effect of this structure.

Both types are suitable for covering with metal tiles. Having chosen an option that suits the characteristics of your home, it’s time to move on to more subtle calculations.

What should the structure be prepared for?

The design of a gable roof rafter system can be called correct only when it is capable of maintaining the stability of the entire roof under certain loads.

First of all, this concerns the weight of the roof (in particular, metal tiles weigh 3.5-4.5 kg/m2), sheathing, insulation/waterproofing/vapor barrier materials. On average, these components should not put pressure on the rafters by more than 40-45 kg/m2. To guarantee stability, add another 10% to the resulting value - this is a calculation for a constant load.

The local climate can also bring surprises. We are talking about the intensity of precipitation, winds, snow load:

Wind: determined by the product of the regional indicator multiplied by the correction factor (all these values are contained in SNiP “Loads and Impacts”). In addition, if the house is surrounded by high-rise buildings or other objects with a higher height, then the wind loads will be much less. And the situation is completely opposite if the house is separate.
Full snow load: product of snow weight and correction factor (it takes into account both wind and aerodynamic effects). SNiP 2.01.07-85 contains the values of these parameters. They range from 80 to 320 kg/m2.
Special loads. By the way, uncharacteristic for our latitudes. This category includes high seismological activity, storms, tornadoes and hurricanes. For those in whose area such phenomena are not regularly observed, it is enough to make a simple safety margin described above.

Please note that roofs with "non-smooth" slopes (i.e. those whose shape is not a regular rectangle) require a different approach to load calculations. Such a slope is conventionally divided into separate zones. For each of them, the required amount of materials is individually calculated (as for “regular rectangles”). To complete the data on such a slope, all the results obtained from its sections are summarized.

Detailed frame calculations

The angle of inclination of the roof depends on both climatic factors and the roofing material:

When covering a roof with metal tiles, the minimum angle is 20 degrees, and the maximum should not exceed 45.
For areas with snowy winters, it is recommended to make the roof angle as sharp as possible. Thanks to this, snow will not accumulate on it to a critical mass.
If strong winds prevail at the location of the house, then the roof should be flatter. Otherwise, there is a high chance that it will simply be blown away during the next rush.

But it is not enough just to have sufficient steepness of the slopes. After all, parameters such as the length and pitch of the rafters are no less important:

The length of the rafters is determined by the ever-current Pythagorean theorem. Let us denote the desired value as “C”. “A” is the height of the roof (the distance from its top to the attic floor), and “B” is half the width of the building. The sum of the squares of “A” and “B” is equal to the square of the value “C”. Take the root of this result and get the required length of the slope.

Do not forget to add an additional 60-70 cm to it, intended to form the roof overhang. If rafters of the required length are not found, then you just need to install additional “fillies”.

The optimal pitch of the rafters, which will allow you to support the roof made of metal tiles, is the range from 80 to 100 cm (with a rafter cross-section of 50x150 mm).

The number of required elements is equal to the result of dividing the length of the slope by the pitch of the rafters (add 1 to the resulting value). For both sides of the roof, this result must be multiplied by two accordingly.

The remaining design details are applied depending on the values of the previous parameters:

Mauerlat is a timber with dimensions of 120x120 mm, 150x150 mm and more.
A puff is a board whose cross-section varies from 30x150 to 45x150 millimeters.
Racks, struts - usually timber with a cross section from 100x100 to 120x120 millimeters is used.
Bench - its cross-section should be the same as that of the rack (because it will be attached to it).

The pitch of the sheathing depends on the magnitude of the transverse wave of the metal tile:

● For a wave of 300 millimeters – 300 mm pitch of the sheathing (in the area of the roof overhang – 230 mm)

● For 350 – 350 (in the overhang area – 280)

● For 400 – 400 (in the overhang area – 330)

In addition, there are different dimensions of lumber for sheathing. The most popular option is a cut board 24 (25) x 100 millimeters, suitable for arranging simple and light roofs. There are also sizes of 32x100 mm - they are suitable for laying metal tiles on the base of a galvanized sheet (the thickness of which is at least 0.5 mm). Often used in complex structures roofs.

Step-by-step installation analysis

The first thing you need to do is lay waterproofing material on the wall of the building. But only if it is made of brick or stone (for wooden ones you can skip this step). An ordinary roofing felt material, which is attached to mastic, will suffice.

After this, we take on the Mauerlat, which can be installed in any of two ways:

On a threaded rod mounted in a reinforcing concrete belt (it is laid along the top of the walls on which the Mauerlat will be installed). To do this, holes are drilled in the timber, the diameter of which should exceed the diameter of the stud by 2-2.5 mm.
Fastening with expansion anchor bolts. Holes of the required sizes are drilled for them, and after installation, these fasteners are tightened to fix the power plate.

If, after installation of this element, protruding ends of the studs/anchors remain, they must be cut off with a grinder. After this, marks are applied to the mauerlat indicating the places where the rafter legs are inserted.

We make cutouts on the rafters that go deep into the board (but no more than a third of its width). These cuts should fit snugly against the outer edge of the Mauerlat.

For rigid fastening of the rafters, you can install metal corners, screwing them to the markings on the Mauerlat. A rafter leg is laid between them, fixed to these corners using self-tapping screws or through bolts. Please note that it is more convenient to fasten the corners to the rafters when the latter is connected to its pair in the area of the ridge.
The sliding mount is more versatile because... provides the rafters with the possibility of slight mobility. This saves the roof structure from deformation when the walls shrink (the mobility of the rafters makes it possible to compensate for these fluctuations).

Now it's time for the rafters. The first two pairs are mounted on the border with the gables, tried on and adjusted to each other. After this, they are fixed in the area of the ridge and a cord is pulled between these two pairs. It will be a guide for the correct installation of the remaining rafters.

Having lined up all the other rafters on the Mauerlat along the line of the lace, they must be fastened with a ridge girder. It is attached to each pair with metal corners on both sides.

When the required rigidity is achieved, the rafters are secured to the Mauerlat. At the same time, strings are installed on them (if there is a load-bearing wall inside - on the upper part of the rafters, if not - on the lower part).

The centers of fixation of the racks are determined (on internal load-bearing walls or on tie rods located in the lower part of the structure). Struts are attached to the installed racks for additional stability of the frame. If the length of the rafters does not allow the formation of a roof overhang, then they are “extended” with fillets.

After this, waterproofing is attached to the rafter frame:

Rolled products are laid with longitudinal lines horizontally from the eaves. The overlap is approximately 10-15 centimeters. Fixation using a stapler with staples.
When dealing with a diffuse membrane, it is necessary to monitor its position. The marked side must face the street.

A counter-lattice is screwed onto the rafters on top of the waterproofing using self-tapping screws. It presses the material and leaves a ventilation gap above it.

Next, it is recommended to take care of the roof overhang. We attach a wind board to the end side of the rafters. On top of it, rafters and counter battens we install the first batten of the sheathing. We install drain holders on it (the step between them is 1 meter) and a metal wind strip. The latter protects the wood from moisture. The distance between the remaining slats of the sheathing, as already described earlier, depends on the transverse wave of the metal tile.

You can begin installing metal tiles on the finished sheathing:

If the sheets of this material cover the entire length of the slope in size, then installation will be very simple. The first sheet is applied from the edge of the slope and attached to the sheathing with self-tapping screws. The next one is mounted with an overlap on one wave. Thus, the tiles are installed along the entire perimeter of the roof.
Be sure to make sure that there is a gap of 5-7 centimeters in the area of the ridge, which will provide ventilation for the roof structure.
If the sheets are not very tall and do not cover the slope from top to bottom, then their installation accordingly begins from the cornice. The overlap of sheets in one row is one relief wave. In the same way, all horizontal rows of metal tiles are laid on top of each other.

A gap on the ridge of 5-7 centimeters is also required.

The final touch to the roof structure is the ridge element. This should be any breathable seal. Good ventilation will help avoid moisture accumulation in the roofing “pie”.
Do not forget that all elements are attached using self-tapping screws with a rubber O-ring under the press washer. It protects drilled holes from sedimentary waters.

What do we end up with?

The process of installing a gable roof and designing a rafter system for metal tiles is very expensive and by no means the easiest. Particular vigilance is required not so much during installation as during the initial calculations of all design parameters. Just one slightest mistake can soon lead to negative consequences.

However, a do-it-yourself rafter system for a gable roof is a more than realistically possible idea.

But taking into account all possible difficulties, a couple of assistants when assembling the structure, as well as preliminary consultations with experienced specialists on calculations and design issues, will significantly determine the quality of the result for the better.