All you need to know about rafting farms

During the construction of any roof, the most important is safety and reliable protection against negative environmental influences. To achieve this, it is necessary to use wooden or metal systems rafters.

What it is?

A plump farm is called a whole complex of structural elements, which includes doom, discoloration, racks. After assembly, the design will be a reliable “skeleton” of the future roof.

Under the rafter farm, first of all refers to a hard structure, relevant when building scanty roofs. The main task of the farm is to distribute the main load that the walls of the structure have. Most often such structures from wood are made, but it is possible to install from similar materials.

The basis when erecting a wooden typical design, rounded bars protrude, ordinary boards. Additional elements are joined to the main design, literally waving into the necessary sections. If the parts are made of boards, the bolts, ring knipes, and nails participate in the accession.

Farms having metallic bases of stretched shape are used when the construction of large-scale buildings, when the span has a length of over 16 meters. If we are talking about the construction of the design with the help of stretched racks from the boards, it is difficult to achieve reliability of the attachment of nodes. However, if you use metal elements, then firmly fasten the nodes are quite easy.

To assemble a wooden farm, you need to make a lot of effort. Much faster the process will go, if used not only wooden parts, but also metal. This type of assembly is called combined.

When building residential buildings, extremely rare planners resort to the roof option with open farms. Most often farm just close with special ceiling overlap. With the construction of the construction of the production orientation on the roof, there are open farms.

The carriers of such a design often become beams. Construction beams are made on the basis of reinforced concrete, stacked under rafters and overlap the steps of the columns in length 12, 18 m. These parts of the design perform the role of an intermediate support.

Primary requirements

Regardless of the type of building materials, before the main finish, it is necessary to build a strong and reliable construction, whose main task will be the stability and strength of the roof.

If the design with elements from submistropyl and rafter complexes was erected correctly, then its reliability is guaranteed. Construction with ease will withstand the load of any type, whether they are temporary or permanent.

Farm material and construction requires maximum strength, safety and stability.

Review of species

When choosing a design and material from which the roof belated will be made, the material of the walls themselves should be taken into account. Columns made of metal or reinforced concrete canvases, driving systems and walls from bricks will become a reliable support for carrier bases.

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Farm characteristics allow them to classify them according to the parameters:

  • architectural design design;
  • Scheme in statics;
  • lattice type;
  • Outlines of rafter belts.

The most important criterion for the classification of farms is the outline of the belts. It is calculated when taking into account the parameters of the span, structural features of the roof, as well as when taking into account the level of possible load. The choice of material also directly depends on the slope (the bull slope is taken at the maximum height).

  1. With the construction of flat roofs, farms equipped with parallel belts are most commonly involved.
  2. If steel or asbestos-cement sheet floors have become the material for the construction of the roof, then the support system in the form of a trapezium becomes the best option.
  3. In private construction, you can most often meet the structures of triangular configurations.
  4. When taking into account the outlines, the selection of the grid. If systems in the form of a trapezoid or species with parallel belts are activated, then the lattices of triangular forms become the best option. The lattice is strengthened with additional racks.
  5. Frequently used lattices equipped with shprengels

On the basis of constructive design

For design design, all farms can be divided:

  1. on heavy (double-lit), with two shaped sheets in the design nodes;
  2. Light (single), in the design of which only one sheet.

During the construction of buildings that have a long span (industrial buildings), large weight designs are used. When erecting huge industrial premises, the “skeleton” of the roof performs the role of a frame that supports support systems.

By material

By varieties of materials, farms system can be created:

  • from wood;
  • of steel;
  • Combined.

Form Selection Tips

Consider how to make a choice of formal configuration design. In order for the selection of forms to be correct, the following criteria are important:

  • type of roof coating material;
  • There are or no overlap on the ceiling;
  • the angle of inclination of the roof;
  • Features of the compounds of the rafter elements.

When building a flat roof covered with bitumen rolls, it is better to use designs in the form of a rectangle or a trapezium.

If the corner of the angle is above 12 degrees, and if the coatings are hard, then it is better to use constructions in a triangular format.

Selection of material

The most responsible and important is the choice of material for construction. Special requirements are presented to the material: it should provide the highest strength, be sufficiently rigid and not deformed. Relevant and price indicator, because the cost is a fairly tangible factor, especially in private construction.

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Wood is considered one of the most popular and inexpensive building materials.

Designs made of wood are relevant for the following cases:

  • When erecting the roofs of the attitude of the attic;
  • when installing objects both industrial and other orientations;
  • When restoration of flat roofs of various buildings.

The main features of wood farms, compared with similar constructions, can be called the following:

  • Design speed increased several times;
  • Automated installation and simplicity of all stages of construction;
  • Easy when carrying out installation works (items are ready, they remain only to install them correctly);
  • the ability to realize even the most bold design ideas in relation to configuration, forms and other aspects;
  • The design weighs relatively a bit;
  • The possibility of installation in situations where the spills have large dimensions (maximum length – 18 m);
  • the ability to warm up, the overall simplicity of this procedure;
  • excellent technical and operational qualities;
  • The material is considered suitable for processing in industrial environments, and therefore refers to the first category of fire safety materials;
  • Ecology.


Steel structures from the profile pipe can boast of increased rigidity, unlike wooden competitors. Due to this quality, metal systems rafters are often used in case the designs need to give an additional rigidity. This is a good option if high-length farms are installed, over 10 meters. In this situation, not only rafters must be made of steel, but also the supports of the skate, and the Mauerlat bar.

Installation should be made not using the combined parts of wood, and when using special chamber profiles.

For fasteners, rafters are needed. Corses that have been welded.

The main advantages of the farms of steel:

  • Higher strength compared to other options;
  • resistance to various corrosion phenomena and physical influence;
  • The material is not able to rot and has special resistance to deformation;
  • long service life;
  • If it is required to overlap the perimeter of a large-sized building, it is very easy to do with steel elements.

Some minuses of metal structures:

  • The design itself weighs a lot, the use of such elements gives an additional burden on the roof;
  • When installing, you must use a special technique (to raise products to a certain height);
  • Details do not withstand too sharp temperature differences and can be deformed;
  • quite high cost.

Farms from steel are divided into three types:

  • having parallel belts;
  • in the form of a triangle;
  • polygonal.

To build a soft roof perfectly fit the rafter structures having parallel belts. You can also use polygonal models.

If materials are used in the form of sheets, then the best option will be the design of the triangular form.

Farms that are produced in factories are suitable for universal sizes of flights – 18, 24, 30 and 36 meters long.

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When creating decisions of structures and belts, corners are most often used. Separate elements are fastened through welding. The most reliable can be called the design, with the arrangement of belts of which the beams with wide shelves were involved (brazers).

Production itself is not too complicated, such a way of work requires a smaller amount of material. At the same time, the strength and reliability of the design remain at the height.

Features of load calculation

When installing the rafter system, it is important not only to correctly determine the best form of form and material, but also carry out the calculation of the planned loading.

Loads can be divided into three types:

  • unchanged: this type includes the total weight of the roof;
  • temporary: weight of snow cover or land, strong wind stream;
  • Special type of load: earthquake opportunity.

The system of rafters, created with the help of beams and farms, becomes carrier. Consists of such a system from a variety of elements. When installing a specific type of construction and its shape, it is important to understand that it is always a very responsible process. Each stage has its own value, but a special place is given to the design. All calculations must be made correctly, many factors are taken into account, because the safety of future construction depends on it.

Calculation is based on the most complex calculations, which can only be professional.

Montaja technology

As an example, below presents the easiest option of the mounting work of the rafter system (used when building a single-piece roof). Design can be performed with your own hands.

  1. First you need to calculate the drop in the walls between the walls: TGL x W. Icon “sh” denotes the distance between two walls-supports. Tangent angle (roofing slope) is indicated by the “TGL” icon.
  2. After the calculation should prepare the desired number of rafters from the boards, processing wood by antiseptic.
  3. Next follows Maurolat. The board must be commensurate with the size of the diameter of the walls. The beam must be strengthened very hard and hard, it will be worth a good waterproofing. When installing, it is necessary to observe the horizontal position of the design.
  4. Then the sections for laying the rafter bases are designated (after designation of such sites, notes are cut).
  5. Farms must be so located so that they go to the protrusion on the supporting structure by about 30 cm. Calcular can be made using construction brackets and special bolts.
  6. The outcome of the work will be the laying of the root and backups. If the base rafters exceeds 4.5 meters in length, then the backups are simply necessary. Next strucks installed on top of the installed structures.

About how the assembly of a lumpy farm occurs, you can learn from the video below.

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