The more carefully they are done preliminary calculations, and in particular, the more correctly the pitch of the rafters for metal tiles is determined, the more reliable the frame of the future roof will probably be.
If, during calculations, the load on the rafter structure is determined incorrectly, or the parameters of the rafters are underestimated, in the future such errors may cause damage to the roof covering or changes in shape rafter legs, and also lead to the collapse of the rafter base.
When calculating the roof structure, it is also necessary to calculate the distance that will be between the rafters. Determining these parameters is not particularly difficult if you correctly use the general methods for calculating such distances, accepted among specialists.
Calculation of the pitch between rafters
The gap between the rafter legs is usually called the pitch of the rafters or the step of the rafter legs.
Usually in a roof structure this distance should not be more than one meter, the permissible minimum is 60 centimeters.
To calculate for a given roof length required quantity rafters, accordingly, to determine the pitch of the rafters, you must proceed as follows:
- The length of the slope is measured along the eaves of the roof.
- The resulting value is divided by the unit of measurement, in this case by the selected rafter pitch. For example, when the rafter pitch is 1 meter, the length is divided by 1, if the pitch is 80 cm, then by 0.8, etc.
- At the next stage of calculations, one is added to the result obtained, then this value is rounded up. This way the required number of rafters that are supposed to be installed on one roof slope is determined.
- The total length of the slope will need to be divided by the resulting number of rafters - as a result, we obtain the value of the interaxial gap between the rafters, which is called the rafter pitch.
For example, with a roof slope length of 27.5 m and a rafter pitch 1 m long, the calculation will be as follows:
Accordingly, 29 rafters will be needed for the roof slope.
So, 95 cm is the gap between the axes of the rafters installed on the roof slope.
However, the general calculation methodology does not take into account the features of certain roofing materials.
The most common types of coatings can be considered in detail - how, according to the recommendations of professionals, the pitch of the rafters should be selected during construction rafter system depending on the type of roofing material chosen.
Rafter spacing for metal roofing
During construction country houses The most common roofing material is metal tiles.
Metal tile roofing looks like clay tile flooring, but has multiple advantages over clay roofing..
- As for installation, sheet metal tiles are much more technologically advanced, and the time spent on roof construction is significantly reduced.
- such roofing material much lighter in weight than tiles made of natural clay: the difference in weight is 1 sq.m. will be about 35 kg - depending on the thickness of the natural tiles.
With such a reduction in the weight of the roof deck, it is possible to significantly reduce the requirements for many parameters when calculating the rafter system for metal tiles. For example, you can increase the installation pitch of the rafters, reduce their thickness, and reduce the cross-section of the sheathing bars for metal tiles.
To cover the roof with metal tiles, the gap between the rafters is determined in the region of 60-95 cm at the cross section structural element 150 by 50 mm.
According to experts, a thickness of 15 cm will be sufficient for insulation placed between the rafters, and this thickness will be enough for good thermal insulation of the roof. But for reliability, it is better to choose insulation with a thickness of 20 cm. With this indicator, the cross-section of the rafter leg also increases to 20 cm.
To improve ventilation of the space that is intended to be filled with insulation, when installing rafters, a series of holes with a diameter of 10 mm are drilled in them (rafters) near the top edge.
In general terms truss structure for metal tiles is fundamentally no different from any other. Perhaps its only peculiarity is that the upper support of the rafters is placed not on the ridge beam, that is, on the side, but on the ridge girder - from above.
Between the joined wooden parts at the top, a free zone is created, which ensures air circulation, which reduces the risk of condensation forming under the roof deck - this is important for metal surface material.
When installing the roof of a wooden house, which involves replacing the mauerlat with an upper log crown, an incorrect calculation of the rafter pitch will make any changes almost impossible, since notches are usually made in the crown in order to increase the reliability of fastening.
Elements for strengthening the rafter system
A fastening element such as rafter tightening is used when the roof is erected using hanging rafter elements.
To tighten the rafters, a horizontal beam or log is used, attached to the base of the rafter legs - this can significantly reduce the horizontal expansion forces that act on the walls of the building.
A tie can also be installed above the base of the rafters, but with this method it is made somewhat more powerful, which subsequently has a beneficial effect on the durability of the roof.
The filly is an extension of the rafter leg, which is attached to the leg with ordinary nails. The rafter fillet is made from a board half as high and thick as the rafter leg. Moreover, its length is approximately 1-1.2 meters, of which one half forms an overhang, the second provides attachment to the rafters.
When installing a rafter system under metal tiles, or under any other roofing material, special corners for fastening rafters are used to fix its elements. The advantages of such an element are ensuring high bearing capacity, as well as the ability to fasten without the use of special tools. The wooden structures of the rafter system and the corners are connected using screws or nails.
Rafter processing
There are two main problems for which rafters need impregnation:
- Protection against fungus and insects. If the rafters are not treated with antiseptics in a timely manner, there is a high risk of grinder beetles appearing in the wood, which will gradually gnaw away at the wooden parts of the roof.
Fungus and mold pose no less danger to rafters. Improper installation of roofing materials can lead to such undesirable results as mold and fungal colonies, and these factors destroy rafters even faster than insects.
Having correctly calculated all the necessary parameters of the future rafter system, you can begin its construction, maintaining confidence in its future reliability and durability.
Metal tiles are a lightweight, durable, effective roofing material, ideal problem solver 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 your 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 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. Outside 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.
In order for traditional behavior steel roofing did not bother the owners and did 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 they 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 one, clearly not intended for use attic space it makes more sense to place insulation between 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 most simple option In the construction of a rafter system for laying metal tiles, a design with two slopes is rightfully recognized. Its rectangular planes are ideal for laying sheets of similar shape. The hip or one will require much more effort with 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 arrangement will be increased by purchasing 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. The lines of all structural parts of a gable roof are 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, design features which depend on the architectural data of the box being equipped. Manufactured and produced 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, along which air flows wash the thermal insulation and inner surface metal tiles.
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 extending the life cycle of the roof itself and wooden parts 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 is prohibited from contacting the insulation so that moisture does not appear in its 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 air gap between the waterproofing and the metal covering and serves as the basis for installing sheets of metal tiles.
- Finish coating.
As a waterproofing roofing systems bitumen varieties cannot be used under metal tiles and corrugated sheets roll materials. 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 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 - truss 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 ventilation gap, fixing waterproofing and fastening 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 eaves line is always less step between row laths. So it is necessary that the first transverse step of the sheet lies exactly on the base.
Video instructions for installation work
The video will clearly introduce you to the process of constructing a rafter system and installing metal tiles:
The diagrams for the construction of rafter systems with insulated and cold roofing pies, disassembled “on the shelves,” represent a general guide to the actions of an independent roofer. In fact, designs are modernized and adapted to the real conditions of a particular facility. However, they may well serve as the basis for your own development.
The distance between the rafters for metal tiles necessarily takes into account the forces resulting from wind and snow loads, the dead weight of the structures, and the roof. In addition, the following factors influence the pitch of rafters for metal tiles:
- pipe location - wooden roof elements should be 25-35 cm away from the chimney and should not interfere with the straight paths of ventilation ducts and vent pipes;
- roof configuration - it is necessary to have a rafter leg at the junction of the ridge of a gable or hip roof.
All wooden elements of the rafter system are made from coniferous trees, the humidity of which does not exceed 20%.
The pitch of the rafter legs is calculated at the design stage to prepare an estimate. This will significantly reduce the amount of waste and cuttings of lumber.
What do you need to know when choosing the optimal distance between rafters?
Roofing diagram with hanging rafters.
Having collected the loads present during the strength calculation, the designer distributes them evenly across load-bearing walls. The principle of calculation is the same for layered, hanging rafters, only the schemes for fastening the elements in the ridge and on the mauerlat differ.
The minimum and maximum spacing of wooden rafters for metal tiles are regulated at 0.7 m and 1.2 m, respectively.
When choosing a pitch of 60 - 100 cm, the length of the rafters cannot exceed 6 m; if it is reduced, a spread of up to 1.2 m is allowed. If you place the legs more than 60 cm, this will unnecessarily weigh down the roof and increase the construction budget. If you increase the pitch by more than 1.2 m, the load-bearing capacity and service life of the structure will sharply decrease.
A continuous lathing made of wood-containing slabs adds strength and rigidity to the rafter system. In this case, it is allowed to increase the pitch by 0.3 - 0.2 m compared to periodic lathing made of timber or edged boards. However, to save construction budgets, continuous sheathing for metal tiles is used extremely rarely. The material has sufficient strength and rigidity due to additional transverse profile ribs.
A step greater than 1.2 m is not used even when using rafters made of rolled metal, despite the sufficient safety margin of the material. This is due to the possible deflection of roofing sheets during heavy snowfalls and hurricane winds.
The cross-section of the timber from which the rafter legs are made also affects the pitch of the rafters, since the support area of the sheathing and the weight of the roof change. The best option a beam of 150 x 50 mm with a discharged sheathing with a pitch of 4 - 7 cm is considered, depending on the pitch of the transverse wave.
Calculation example for a gable roof
When carrying out a project by specialists initial stage known roofing material. In order to find out the recommended rafter pitch, you can use the SNiP tables, and then adjust the value in accordance with the operating conditions. An example table is shown below:
| Leg section (cm) | Rafter pitch (cm) depending on their length (m) | ||
| 5 | 4 | 3 | |
| board 20 x 2 | 70 | 120 | – |
| board 18 x 2 | – | 100 | – |
| board 16 x 2 | – | 70 | 130 |
| beam 22 x 6 | – | 120 | – |
| timber 20 x 5 | – | 110 | – |
| beam 18 x 5 | – | 90 | 150 |
| log 180 | 90 | 150 | – |
| log 150 | – | 90 | 150 |
| log 140 | – | 70 | 140 |
| log 130 | – | – | 110 |
The table values correspond to the rafters of simple single-pitched roofs. First, the section of the leg is selected, the length of the element, and the distance between the centers of the log or beam are obtained automatically. At the next stage, the length of the slope in the ridge is divided by the pitch of the rafters with the addition of one. Thus, the number of legs is calculated with the number rounded up. Then it remains to adjust the distance between the wooden rafters according to the fact. For example, with a ridge length of 7.5 m, a rafter leg with a section of 16 x 2 cm (board) 4 m long, the result will be:
7.5/0.7 = 10.7 + 1 = 11.7 pcs. round up to 12 rafters.
Specifying the size allows you to calculate the center-to-center distance for installation after installing the outer legs:
7.5/12 = 62.5 cm.
Dormer windows are placed between adjacent rafters; in places where pipes and chimneys pass, the legs are shifted to the distance specified in SNiP. All other elements of the system remain in place, the area adjacent to the pipes is strengthened if necessary:
- a bench is cut into two adjacent legs;
- a short rafter is cut into it at one end, the second is adjacent at the ridge to the element of the opposite slope;
- the offset legs in the upper part rest on a ridge girder attached to at least two trusses.
Thus, the system receives the necessary rigidity without loss of load-bearing capacity, and the fire safety requirements of wooden roof parts are met.
Material of rafter legs
The rafter material is often timber 25 x 10 cm – 15 x 4 cm, which allows reducing the construction budget.
When choosing lumber with natural moisture, the developer is guaranteed to experience shrinkage of the structure in the first year and a half by 5-7 cm in height. By increasing the estimate for the arrangement of the rafter system by 70%, you can purchase laminated veneer lumber, significantly reducing structural loads, and doubling the roof service life.
The distance between the rafters will remain unchanged, however, instead of planed timber 17.5 x 5 cm, recommended by building codes for five-meter legs spaced every 0.6 m, you can get by with glued laminated timber of a smaller section 15 x 4 cm. Transportation costs will be reduced and work at height will be easier , cut of material.
Prefabricated rafters from boards are used in the same truss fastening scheme hip roof. The upper slopes are made of single boards, the lower ones are made of three boards, sewn with self-tapping screws offset in rows.
The choice of metal rafters is justified when the roof configuration is complex, there is an abundance of ventilation pipes, chimneys, which are not possible to bypass in compliance with SNiP and fire safety requirements. In this case, the pitch between the rafters increases as much as possible, since rolled metal is much stronger than lumber.
If the rafters are attached at the bottom to the mauerlat, the step of the legs is not critical; the elements can, if necessary, be shifted to the required distance in any direction. If a support scheme is used on tie rods, which are floor beams, it is much more difficult to displace individual elements. In this case, the amount of cutting waste during sheathing increases draft ceiling, floor of the attic or attic space.
In the vast majority of cases, when repairing a roof, the choice falls on metal tiles.
In addition to the long list of economic and operational benefits, this material It is also interesting for its suitability for self-installation.
Even basic skills will be enough home handyman so 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:
- Economic expediency.
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 long term operation. - 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. In addition, a lightweight 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 use in the design roofing sheet a few protective words. Therefore, the metal base of the canvas is not afraid of either prolonged exposure to moisture or direct sun rays, no 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 set of traditional tools for finishing work:
- electric screwdriver;
- jigsaw or circular saw;
- marker;
- construction stapler with staples;
- metal scissors;
- scotch;
- laser plane builder or construction level;
- roulette.
Important! To cut sheets of metal tiles, you cannot use grinders with abrasive discs operating at high speeds. Their use will lead to overheating of the steel base, melting and destruction of the polymer protective coating. Such damage greatly reduces the service life of the roof.
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.
Funds will also be required personal protection and auxiliary devices: ladder, scaffolding, brush for sweeping away debris, etc.
Find out more about laying corrugated sheets on a gable roof:
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 installation work configuration, 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 sheet of metal roofing will be absorbed into 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 front boards(8) and cornice 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 Convenient with the ability 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 installation of the drain is carried out after laying the metal tiles, then use short hooks, the upper part of which is under roof covering does not start.
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.
Attention! Metal roofing and bitumen waterproofing are incompatible materials. When the roof heats up under the sun, the bitumen will melt and the canvas will lose its ability to repel moisture.
Learn how to make a pediment gable roof with your own hands:
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 horizontal waves on a sheet of metal tile 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 topmost beams of the sheathing 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 of a dormer window) form intersections at a slight angle, the installation of a special strip is required - 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 cornice boards. 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 brick 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;
- 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 fixed to the sheathing by tightening the screws.
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.
For detailed instructions on installing metal roofing, see this video:
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 atmospheric precipitation and sharp gusts of wind penetrating under the metal tiles. In addition, the end strip also performs decorative function: when correct installation its upper edge overlaps crest waves of metal tiles. Screw end strip start 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 layer waterproofing material strip of 150 mm.
Fastening is carried out 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 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.
Attention! Drainpipes are installed with the crimp down, otherwise leaks cannot be avoided.
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.
Further into the space between rafters a layer of insulating material is placed behind the counter-trikes, which additionally reduces noise metal roofing.
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.
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 following describes the safety rules that must be followed when working with metal tiles: video:
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, given 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 an 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 design should be obtained that appearance and its shape resembles a rafter system. 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– in this case, beams or corners should be used, nails and staples are used much less often, the peculiarity 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 of load-bearing capacity will be significantly reduced, which will negatively affect the metal tile structure.
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 quite high level 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 is to choose wooden blocks with a cross-section of 150*150 mm, while the sheathing can be installed at intervals of 4 to 7 cm. In this case, it is recommended to take into account the pitch 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.
