Scheme of installation of the truss system. Do-it-yourself gable roof. Calculation of the parameters of the rafter legs

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The roof has great importance for the integrity of the whole house. Therefore, many are interested in how to properly assemble the rafter system so that it is reliable and does not have to be repaired soon. There are many types of roofs, some of them can be seen in the photo, but single-pitched and double-pitched structures are the most popular. Let's figure out how to make the truss system correctly.

Roof types

Before moving on to how to make a truss system, you need to figure out what the common types of roofs are.

Shed roof - the simplest, even a person who does not have much experience in construction can handle its creation. However, this type of roofing is mainly used in the construction of outbuildings. For residential buildings, gable or mansard (broken) roofs are usually made. These designs are more complex, but you can easily deal with them on your own if you know how to make rafters. gable roof and follow all the recommendations of specialists (read: "").

The most reliable roofs are hip ones, they can withstand even huge loads. They are recommended to be done in regions where there is a lot of snow and strong winds often blow. But their design is also very complex, so it is better to entrust their construction to professionals.

A hipped (four-pitched) roof is used in the construction of square buildings; in its design, it is a kind of hip roof.

The most complex roof is a cross. In its construction, complex structural elements- valleys (grooves). These diagonal auxiliary rafters are installed as additional elements. When building such a complex roof, haste is unacceptable. Most of the snow accumulates in the area of ​​​​the grooves, and the reliability of the roof depends on how to make rafters in these places.

Each type of roof consists of rafters and roofing. The rafters are the load-bearing part of the roof, and the roof surface is the enclosing part.

Types of rafters

Before you put the rafters, you need to find out about them design features and decide on the installation option.

There are two types of rafters: layered and hanging .

hanging rafters - these are inclined beams mounted on supports with different heights. Support can be the outer walls of the house (in the case pitched roof) or both internal and external walls (with a gable roof). Rafter legs do not have to be laid in the same plane opposite the slopes. They can be mounted alternately on the ridge run. Alternate laying of rafters in the ridge area makes it possible to create a truss truss. To this end, all parts are interconnected into a single rigid structure.

Materials for rafters

As for the rafters from the boards, they are not heavy, and they are convenient to install. You can easily work with this material on your own without resorting to outside help. Many experts do not advise making connections with nails - it is better to use self-tapping screws. If the work will be carried out with the help of nails, do not forget about the lining and liners.

As for how to build a truss system, it is better to use cuttings to connect racks with a run or a bed.

Do-it-yourself installation of the truss system, in detail on the video:

Rafter system connection options

The rafter system can be connected in three ways:

• struts;
• racks;
• at the same time struts and racks.

How to properly make the rafters depends on the span between the outer walls. A beam of 10x10 centimeters is used to create a ridge run. Lezhen and Mauerlat can be made from logs, hewn them into two edges, or by taking a beam of 10x10 centimeters.

When making ridge knot it is necessary to nail special clamps made of steel strip to the Mauerlat and run with large nails, taking into account. You can not use steel clamps, but then you need twists of thick wire with a diameter of 6 millimeters.

Regarding how to make a brick or stone house, then a Mauerlat must be laid on the masonry. For its reliable fastening, it is recommended to place a piece of log or timber about 50 centimeters under each rafter leg. Then they are attached with clamps to metal hooks that were previously installed 30 centimeters below the Mauerlat.

Many people have a question about how to make rafters on the roof wooden houses. Rafters in wooden buildings are laid on the upper crown of the wall. A plank truss truss can be created using a crossbar or with spans (6-8 centimeters). Its structural elements are arranged as follows. Make a single puff with the help of boards, the thickness of which is equal to the thickness of the rafters. For double tightening, thinner boards are used (thickness from 40 millimeters). For the crossbar and overlays, 30 mm parts are taken.

How to determine the cross section of the rafters

Before you properly lay the rafters, you need to decide on their cross section.

This setting depends on:

• span dimensions;
• expected load (wind force, weight of snow cover and roofing material);
• step and angle of installation of rafters (roof slope).

There is a dependence of the cross section of the rafters on the length of the rafter leg.

It is expressed as follows:

• with a step of 300 centimeters, bars with a section of 10x12 centimeters or boards with a section of 6x14, 8x14 or 4x18 centimeters are used;
• with a step of 400 centimeters, bars with a section of 10x16 centimeters or boards with a section of 6x20, 8x20 centimeters are used;
• with a step of 500 centimeters, bars with a section of 10x20 centimeters or boards with a section of 8x22 centimeters are used.

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Roofing must be selected taking into account the slope of the roof. Also, the choice of material for the roof depends on financial capabilities. The greater the angle of the roof slope, the more funds will be required to create the roof - this is due to the increased consumption of materials. However, steep roofs are better rain water and snow, so they are more reliable and will last longer. But considering huge selection roofing materials on the market, this will not cause any difficulties.

Creating a truss system for a bath

As for how to make rafters for a bath, it is better to choose a gable roof - then there will be an attic in the building, which can be used to store brooms and other bath accessories (read: ""). Thus, it is desirable to create a truss system for a gable roof, it is easier and more practical.

Rafter system - strong roof frame for holding roofing and other elements.

How well the roof frame is arranged depends on the strength of the roof as a whole.

Otherwise, its functionality, the ability to protect the building from external influences and provide heat in the house may deteriorate.

Therefore, you need to correctly approach the choice of truss systems and correctly draw up a rafter plan.

And you can read how to calculate the truss system.

Depending on the purpose of the room, size gable roof, the device of the rafter system is classified as follows: hanging system and layered.

Hanging system

Hanging rafter gable roof system It is supported only by the load-bearing external walls of the building.

Depending on the width of the span, the roof project, the installation of hanging systems has features.

For small houses

It is advisable to erect a hanging structure for buildings where the distance from one wall to the opposite does not exceed 6 meters. The frame looks like a triangle.

To strengthen the bearing capacity of the faces of the frame triangle, several methods are used:

• Foundations rafter legs at the top they are fixed with overlays;
• Use bars of a larger section on the side parts;
• The bars are fixed by cutting them into the ridge element;
• The slopes for the canopy equipment are built up by cutting an opening for the frame beam in the extended boards so that they converge behind the line passing from the edge of the inner wall to the slope of the rafter.

Using these methods, it is possible to distribute the load throughout the structure.

Strengthening the frame triangle

For mansard roofs

When arranging the frame under, you should pay attention to some points:

• Mandatory installation of the Mauerlat, on which the frame beam is installed by cutting;
• Installation of a crossbar - the basis for a ceiling canopy of a floor. The most effective mounting option is to cut the crossbar into the rafter with a semi-swing;
• The length of the bevel board should be longer than the wall line;
• The cross section of the frame bars should be maximum;
• The puff should be secured with a suspension. With a long tightening, it is required to strengthen it in the center with the help of nailed boards from above and below.

CAREFULLY!

Particular attention should be paid to the fastening of the elements, since the attic is under load from the outside and inside.

In addition, the truss system of a gable roof with an attic is equipped with heaters, which increases the load.

Rafter frame for mansard roofs

For big houses

With a span of more than 6.5 meters, the installation of a hanging system requires the installation of more fixing elements in order to prevent sagging of the tightening, which causes its own weight.

Points to consider:

• It is advisable to make a puff from two bars by cutting, secure with metal plates;
• In the central part of the frame, a headstock should be installed;
• For a confident distribution of gravity to the headstock and rafters, it is better to attach struts, as well as other holding elements.

When installing a suspension-type system, it can sometimes do without mounting a Mauerlat and limit itself to installing boards on a film. In addition, the hanging system is distinguished by the absence of complex nodes, which facilitates the work on arranging the roof frame.

Hanging system

Layered system

The difference between a layered type structure and a hanging one is that the structure has additional support points inside the room. A prerequisite for installing a layered system is the installation of a Mauerlat.

The design of the system provides for the installation of both expansion and non-expansion frame.

Strutless frame

A non-expanding frame should be installed in houses with log walls. When installing rafters, their bases must be attached to the Mauerlat.

Options for attaching the base of the system to the Mauerlat:

• By beveling the sole of the rafter leg in such a way that its area with the Mauerlat is the same, and the cut does not exceed 0.25 cm of the height of the beam. At the same time, the rafters, without connecting to each other, are attached to the ridge element on both sides;
• By connecting with one nail the rafters at the ridge - at the top, and swivel with a flexible metal plate to the Mauerlat - at the bottom.

When attaching rafter legs without connecting them in the ridge part should Special attention pay attention to the accuracy of the calculations.

Even with minor discrepancies in the scheme, the expansion pressure will act on the walls of the building, which can lead to the collapse of the walls.

Strutless frame

With contractions

To strengthen the structure and give it stability, fights are mounted to the racks of the structure. You should use a beam of the same section as for the rafters. To increase the strength of the fight, they are nailed on both sides of the timber.

The same mounting option is effective for firmly fixing the ridge element, which prevents the roof from moving in a horizontal direction.

Frame with contractions

with braces

Struts enhance the bearing capacity wooden frame and provide the strength of the rafter board.

An important requirement when installing the strut is a correctly measured cut angle, which makes it possible to fit the strut tightly to the connected elements.

ATTENTION!

If, with a layered system, the supporting part is located in the center of the frame base, then the brace is attached at an angle of 45 ° to the horizontal line, if the support is closer to one of the load-bearing walls, then the attachment angle may be different: from 45 ° to 53 °.

It is advisable to erect a frame with struts in places where there is a possibility of planting a foundation, or in wooden buildings where slight wall shrinkage is acceptable.

Frame with braces

With two supports indoors

When there are two supports in the form of internal walls, then when arranging the rafter legs, beams are placed under them. If the beams are not installed, then a rack resting on an internal support is nailed to the base of the rafters.

The rafter beams are installed on load-bearing supports. On the supports inside the room, beds are installed, on which the load from the rafter beams from the racks falls. The rafters are cut so that they fit snugly against each other, and fixed.

With this design, the ridge run is not installed.

To ensure the rigidity of the structure, puffs are attached.

The stability of the structure is ensured by means of racks, which are installed horizontally from the inner base to the rafter leg, and jointing - wooden beams that connect the bases of the racks obliquely.

If the structure is spacer, then a beam is attached above the girder, connecting the frame legs - a crossbar.

Layered system

Types of truss systems

Mansard roof rafters

Before installing the truss system under the attic, it is necessary to correctly calculate the load of the roof and take into account other factors, which may affect its functionality. All wooden elements must be treated with antiseptics.

Installation of the truss system is carried out in stages:

• Install the Mauerlat on the waterproofing layer. They fasten the board to the walls with staples or nails and tie it with metal wire to hooks prepared in advance in the wall;
• Frame elements are cut;
• The main rectangle is made from puffs and racks;
• Two middle runs are mounted, to which the lower rafters are attached;
• The structure can be raised to the roof, where the upper rafters are already installed, connecting them at the upper base, securing the ridge beam and the side run;
• Reinforce the structure with the necessary elements: puffs, racks, struts, additional stops.

After installing the frame, a vapor barrier film is laid on it, elements and a covering material are installed.

Mansard roof device

The device of rafters for the attic

The gable roof attic has the simplest hanging system.

For attic floor it is advisable to make ready-made trusses on the ground, and then raise them to the roof, after installing the Mauerlat.

The trusses consist of rafter legs, firmly fixed by tightening at the lower base. You can additionally use struts or headstock.

Of great importance is the fastening of puffs on the rafters. It is recommended to install puffs so that their bars are located half a meter behind the wall line, then there is no need to additionally install an overhang.

You can read how to make rafters yourself.

Farms are fixed with the help of upper and lower runs.

Rafter system for the attic

Gable roof truss system: elements

When arranging the frame of a gable roof, elements are used:

• Mauerlat. An element that is attached to a load-bearing wall. The entire structure of the truss frame is mounted to it;
• Run. A beam connecting the rafter legs on the sides and in the ridge element;
• Puff. A beam attached to the rafter legs, preventing their divergence;
• Grandmother. A beam located vertically and fixed at the ridge and puff;
• Strut. Plank connecting at an angle the bed and the rafter;
• Rack. Vertically rests on the bed and rafters;
• . Beam connecting the upper bases of the rafters;
• filly. The built-up part of the rafter for the overhang;
• Overhang. Additional design, serves to protect the outer wall from rain;
• Crate. Lattice installed on the truss frame for attaching the top layer.

The combination of several elements (rafters, racks, braces) in one plane is called a truss.

Gable roof truss system, drawings and photos below:

Drawing of the elements of the truss system

Knots of the truss system of a gable roof

Reliable fastening of structural units provides strength and endurance of the structure, increases its service life.

The strength of the base of a gable roof depends not only on proper fastening.

It also consists of correct calculation all elements of the frame, from the verified definition of the type of structure at the design stage.

Rafters for a gable roof are connected to different structural elements.

The main components of the design:

• With beam: fasten either with a spiked tooth or a tooth with an emphasis. Additionally, corners are used. They are mounted to the beam by cutting out an emphasis for the spike in the beam with a socket. A single tooth is attached with a spike and an emphasis. If a cut is made, then the distance from the edge of the bar should be 0.2 - 0.4 m;
• With Mauerlat: with rigid fastening, corners are used or washed down, which is fixed with nails or staples, when hinged - moving metal fasteners, when washed down - a nail or staple;
• With skate: cutting off the edge at an angle, fasten end-to-end with nails, fastening with a bracket or patch board. Overlapped boards are fastened with a bolt or studs.

Depending on the span, the elements are fixed:

• grandmother. Top - with brackets and a collar, bottom - with a collar;
• Strut. The top is attached to the rafter, the bottom - to the headstock;

  The truss system of any object is equivalent to the value of the load-bearing structural elements of the house. The roof plays the role of a node under which the stiffening ribs of the building are assembled. Accordingly, when installing the roof with your own hands, it is required to give the maximum value to all structural units, even when using simple option- duplex.

  

  Advantages of gable roofs

  There are a lot of options for pitched truss systems. Among them, simple symmetrical is especially popular. Why? Here are her virtues:

  • On the basis of a gable roof, variations are created to reflect the special architecture of the building.
  • Simple calculations, easy to understand.
  • The one-piece design creates favorable conditions for the dryness of the internal space and the unhindered flow of water, snow and ice.
  • The maintainability, strength and durability of a gable roof are much higher than other options.

  Depending on the size, homeowners always have the opportunity to equip the under-roof space, make it a full-fledged floor or attic. In a word, a gable roof is the right and profitable solution for any object, whether it is a residential building, a summer house or a bathhouse.

  Elements of the truss system

  Depending on the type of roof, structural elements vary. Without knowledge of the appointments of each, it is impossible to arrange a reliable coverage at home. Let's analyze in detail:

  Mauerlat

  The basis of the truss system. It is a beam with a section of at least 150 mm, or an I-beam channel, if the roof structure is metal. It is located on the bearing walls of the object. Its purpose is to distribute the load of the system evenly throughout the structure of the house.

  

  Rafter leg

  Structural basic unit of the system. Together with others, it forms a truss system - strengthening the strength of the entire roof. It is made of a wooden beam, which is not inferior in cross section to Mauerlat or profile pipes.

  

  Rafter rack

  Vertical bar or pipes. Depending on the variant of the gable roof, the pillars can be located in the center and / or on the sides. They take part of the weight of the entire truss system, which is why the cross section is 150 mm.

  Rafter girders

  Horizontal beams laid on racks and under the ridge to support the rafter legs. They provide structural rigidity and relieve stress on trusses.

  Puffs and braces

  Connecting beam for rafters. The action is similar - relieving the stress of a beam or metal and making the structure rigid.

  

  lying down

  Mounting support for racks and struts. To securely connect these two elements, you need a large cross-section beam - 150 mm or a thick-walled pipe of impressive diameter.

  Lathing beam

  Elements laid perpendicular to the rafters. Serve to install the selected roofing and create a multilayer protective cake. The cross section is small - 40–50 mm.

  If the planned roof structure is made of wooden beams, you should carefully consider the quality of the wood upon purchase - the beam should not have knots interspersed, be made of soft wood.

  The wood must also natural humidity, otherwise it will begin to dry right in the system structure, cracking, deforming the roof model, depriving it of reliability and safety.

  Calculation of the truss system

  double roof - complex structure. The project takes into account many factors - natural nuances, wind, constant and variable loads. It is extremely difficult to make calculations on your own, without special knowledge about the climate of the area, the characteristics of the material for the manufacture of the system, and the nuances of pressure distribution.

  Ideally, the calculations are at the mercy of professionals, you can independently choose only the material for coating - the following parameter depends on its type:

  Tilt angle

  The minimum angle of inclination of the roof relative to the parallel of the earth is 5 degrees. However, its dependence comes from the chosen roofing material. In this capacity, traditional slate, profiled sheet, flexible and metal tiles are used.

  

  They are guided by the following rule: the steeper the slope, the more textured the roof can be.
  From 5 degrees for laying rolled protective insulation of the roof. The number of layers matters - up to 15 degrees three-layer coatings, above - two- and single-layer coatings.

  • From 6 - ondulin.
  • From 11 - slate.
  • From 12 - corrugated board.
  • From 14 to 20 - metal tiles.
  • From 15 to 45 - soft roof.

  Thus, the resulting precipitation - snow, water - will not linger on the surface, although complete cleaning requires one's own efforts or the involvement of specialists for the installation of the Anti-Ice system.

  Determining the parameters of the rafters - step, length, section

  The rarer the step, the more impressive the cross-section of the beam or the diameter of the pipes should be. As a rule, for load-bearing structures, this parameter is at least 150 mm, 100 mm - for country houses and related construction - gazebos, baths, outbuildings.

  Next, you need to set the number of rafters per slope: its length is divided by the installation step, which is from 60 to 100 cm + 1 extreme leg. Multiplying the result by 2 gives the total. Depending on the section of the beam, the amount of rafter legs and the installation step vary.

  The length of the rafters is simply calculated if the school knowledge about the right triangle is left in the luggage. The rafter leg is equal to the hypotenuse of the resulting figure. The calculation is as follows: A² + B² = C², where - A is the height of the roof, B is half the length of the pediment, C is the length of the rafter leg. To the resulting value is always added from 30 to 70 cm for cornice overhangs.

  Types of truss systems

  Before getting down to work, it is important to choose a truss system option for a gable roof. There are few of them, each has its own advantages and disadvantages:

  hanging

  Suitable only for a standard roof width of 6 m, respectively, this is the length of the rafter leg. Fastening occurs by fixing the ends to the ridge run and the bearing wall. Be sure to install a puff that levels the stress and pressure of the structure.

  In addition, they will play the role of load-bearing beams. Without them, the structure will disperse under weight. The advantages of the option are in the absolute dryness of the roof surface during the off-season, and in less deformation at the time of shrinkage.

  

  Layered

  The option is suitable for any roof width. Reliability and stability is ensured by fixing the bed to the Mauerlat. Thus, the pressure is leveled by the rack, which reduces the tension in the rafter legs. The advantage of the system is simplicity, but the design requires large investments - additional lumber is required to equip the beds.

  hybrid

  These systems are typical for multi-pitched roofs, where transitions are accompanied by numerous reinforcements, beams, posts, beds, slopes and other elements for the stability of the entire structure. The device is expensive and complicated, so only a professional should deal with the project and construction. At least curate it.

  Do-it-yourself installation of a gable roof

  So, when the option of the truss system is selected, lumber is purchased, a roof project is drawn up, you can get to work. You cannot deviate from the sequence of steps. This threatens to delay installation and loss of structural reliability.

  Mauerlat mount

  If the length of the beam for installing the Mauerlat is insufficient, an extension is made. Using the half-tree cutting method, the ends are connected. Additional fasteners are anchor bolts. Do not use self-tapping screws, dowels or nails - they are unreliable. Mounting to the wall is as follows:

  • There must be a margin of at least 5 cm from the edge.
  • Holes are drilled along the wall for inserting fasteners. Similar actions are carried out with a bar.
  • Mauerlat is attached to the edge with steel studs. The fastening step is more often 2 times than the distance between the rafter legs. Subsequently, before installing the main units, they are guided by metal marks.

  Important - before laying the Mauerlat, the edge of the wall is protected with waterproofing. Spread one layer even if the house is made of wood.

  Making and fixing rafters

  Roof trusses are convenient in that they can be assembled on the ground into a finished structure and moved to the roof. This will reduce installation time, however, the model is heavy and lifting equipment will be required, which, of course, will increase the cost of the project.

  For budget construction, another method is suitable:

  • At the bottom and top of the rafter legs, a gash is made to attach to the Mauerlat and the ridge run. This must be done separately with each unit, after lifting the wood up.
  • Places for fixing are marked on the Mauerlat and a ridge run is installed: racks are installed along the gables, on which a beam is placed. If the length is not enough, it is increased, but in a different way, unlike the Mauerlat - a board is screwed to the junction from both sides.
  • Depending on the chosen model of the truss system - layered, hanging - they make cuts in the ridge beam, Mauerlat or drill holes in them for fasteners.
  • Next, begin the installation of rafter legs from opposite ends of the roof, gradually moving towards the middle. Between the corners of the extreme trusses, it is not bad to stretch the cord to exactly match the entire horizontal part.
  • Between themselves, the rafter legs are connected by puffs and struts. Under the ridge part, at the angle formed by the rafters, wooden linings are stuffed, and the ends themselves are tightened with bolts.

  More recently, professional builders have begun to use sliding fasteners for roof installation. Metal plates securely hold the bearing elements and at the same time move due to shrinkage. This cancels out its effects.

  The work of fixing the rafters is hard and long. You should calculate the time in advance - you can not leave the roof unfinished during the rainy season, otherwise the rigidity of the structure will be lost in the future due to absorbed moisture.

  Gables and framing

  The side parts of the roof - gables, are made in the form of ready-made shields from boards and are completely installed at the top. Difficulties should not arise - it is only important to carefully file them at the required angle. It is necessary to fasten the crate only after the final appearance of the roofing is known. For example:

  • Under the corrugated board, the step of the crate beam will be 440 mm.
  • The metal tile is fastened to the crate in increments of 350 mm.
  • A soft roof needs a solid plywood coating.

  It is important to note the places for passage chimney- the crate should not come into contact with brick or metal surface. The distance to the hot unit is at least 15 cm. Before installing the lathing, the finished roof is covered with waterproofing with allowances extending beyond the edges of the walls. Then the beam is mounted.

  If it is decided to make an insulation cake from above, then first the vapor barrier is strengthened from the inside, then the selected material is put into the boxes formed by the rafter legs. Next, waterproofing and wind protection.

  Then it is required to re-mark the contours of the rafter legs with a beam 20 * 20 and then fill a new layer of the crate, along which the roofing material will be laid - the formation ventilation ducts. This method will save the capacity of the under-roof space if the owners are going to use it for a specific purpose.

  Roofing material flooring

  Regardless of the type of roofing raw material, installation starts from the edges of the roof and leads it up, laying one unit on top of the other. Thus, rain moisture will not get under the material.

  The method of fastening depends on the type of material - soft tiles or tiles with a bitumen or polymer base are fused. Solid profiled sheets - ondulin, metal tiles - are fixed in pre-drilled holes to the crate, using rubber pads to seal and preserve the anti-corrosion layer.

  As a result: the description of the installation of the truss system and the roof is easy only on the screen or paper. In reality, the process is complex and multifaceted. Therefore, if knowledge is not enough, it is better to invite professionals to work - their work is always guaranteed.

  The truss system is the roof frame, which is the basis for the roofing decking.

  The rafter system is designed to withstand the load of the roof, taking into account natural loads: winds, snow, rain.

  The roof option is approved at the design stage.

  The purpose of the roof includes several functions: warmth in the house, protection of the premises from natural phenomena, therefore the truss system must be given special attention.

  You can read how to calculate the truss system.

  It is customary to classify truss systems so that the task of choosing a variant of the future roof is easier to solve:

  • Shed. The most simple. More suitable for utility rooms, baths, small private houses, gazebos. Provides for the inclined position of the structure at a slight angle (no more than 25°);
  • gable. Used for small houses and suburban buildings. They have the shape of a triangle rafter boards connected by a beam and located at a certain angle;
  • Gable broken lines. They have two slopes with a fracture, thanks to which it is possible to increase the area of ​​the attic;
  • Tri-slope (semi-hip). They have two trapezoidal slopes, which are connected by one end triangular slope (hip);
  • Four-slope (hip). Used for residential buildings require a significant amount of labor. They have two end triangular slopes and two trapezoidal;
  • Tent. Used for square buildings. They consist of four triangular slopes, the upper corner of which is connected in the center of the roof;
  • Multi-forceps. Consist of trapezoidal or other slopes different forms, interconnected.

  The most suitable designs for - and broken gable. There are others, but they are less common and not as practical as those listed above.

  Rafter structures are also classified into:

  • Hanging. With this type of roof frame due to the lack of load-bearing walls in the room;
  • Layered. Rafter installation option, providing support on a load-bearing internal wall or support in a building.

  The calculation of the material for the roof frame when designing a building is based on the intended configuration and load. Do-it-yourself rafters are not difficult to do, it is important to approach the matter wisely.

  

  Rafter systems of layered and hanging type

  Calculation of the load on the rafters

  To correctly calculate the load on the rafters, it is necessary to take into account many factors that can affect the severity of the structure.

  Important metrics to consider:

  • Constant load: includes a mass of roofing cake, covering material;
  • Temporary load: constant and maximum amount of snow, rain, intensity of wind gusts, and in areas with high seismic activity - the effect of storm winds, tornadoes, hurricanes.

  In addition, you should keep in mind the mass and strength of the rafter legs, as well as pay attention to the fastening of the gable roof rafters and the installation option.

  

  Scheme of truss systems

  The distance between the rafters of a gable roof and the thickness of the rafters

  The rafter pitch of a gable roof is the empty space between the rafters. The functionality of the roof depends on the correct calculation of the step. As a rule, the step is about a meter.

  For a more accurate calculation of the distance between the rafters, there is a certain calculation scheme:

  1. Determine the length of the slope.
  2. The length of the slope is divided by the distance between the rafters.
  3. To determine the number of rafter boards, one is added to the resulting value and rounded up. This determines how many boards are needed per slope.
  4. The length of the slope is divided by the number of boards, get the distance between the rafters.

  This calculation is not always final.

  Additionally, you should take into account the load of the roofing (its mass), the thickness of the rafters, as well as the dimensions of the rafters for a gable roof.

  The thickness of the rafter board largely depends on the covering material:

  • . Boards are used with a section of 5x20 cm at a step of 60 to 90 cm with a decking of a batten with a section of 4x5 cm;
  • . Rafter boards - 5x15 cm, step - from 60 cm to 95 cm;
  • . The cross section of the board is 6x18 cm or 5x15 cm, the distance between the bars is from 80 cm to 130 cm;
  • . The cross section of the rafter is 5x15 cm, 5x10 cm with a step of 60 cm to 90 cm;
  • . The cross section of the beam is the same as on the corrugated board with a step of 60-80 cm.

  All indicators should be taken into account and the thickness of the rafter should be accurately calculated so that there is no excessive load on the foundation.

  Incorrect calculation of the length of the gable roof rafters, as well as incorrect calculation of the pitch indicators, can lead to sagging of the roof.

  Do-it-yourself installation of gable roof rafters requires taking into account the weight of the rafter board and all additional fasteners designs.

  

  What is the truss system

  Rafter construction - a complex system and installing a gable roof truss system is not an easy task. truss system consists not only of rafter boards, but also of other additional elements:

  • Mauerlat. An element that distributes the entire load evenly on the supports;
  • Run. Boards fastening the legs of the rafter: at the top - a ridge, on the side - a side run;
  • Puffs. Connecting beam, which prevents the divergence of the rafter legs;
  • Struts, racks. Bars that fix the stability of the rafters, resting on the bed;
  • . Lattice of bars, which is superimposed perpendicular to the rafters. Transfers the load of the covering material to the truss frame;
  • . Connecting beam, which serves as a union of roof slopes;
  • Filly. If the length of the rafter legs is insufficient, they are mounted to form an overhang;
  • Roof overhang. Goes beyond the bottom line of the slope to prevent precipitation from falling on the walls.

  The rafter system implies rafters, stretch marks, braces and racks located in the same plane. They are located in such a way that the main load of the roof structure falls vertically on the external load-bearing walls. Therefore, the manufacture of gable roof rafters is a very important process.

  

  What is the gable roof truss system

  Installation of a rafter system with layered rafters

  A layered rafter system is used when the span does not exceed 6.5 meters.

  In the presence of load-bearing structures inside the building, it is possible to install additional racks.

  The main support of the rafter legs is the Mauerlat.

  Mauerlat installation

  Before mounting the Mauerlat, it is necessary to install an armored belt. It consists of a formwork in which reinforcement is laid and poured with concrete. At the base, with concrete that has not yet hardened, studs are installed, to which the Mauerlat is then attached.

  Mauerlat - a bar that fits on a support ( bearing wall) and is the base of the truss frame. Pre-laid layer waterproofing material. If the length of the beam is not enough for the length of the wall, then it is increased.

  • Check if the diagonals are equal. A discrepancy of a few centimeters can lead to a frame conversion;
  • Fix the corners of the Mauerlat;
  • Attach the Mauerlat with studs or wire. The studs are tightened in two stages, having previously drilled holes for them.

  The stability of the roof structure depends on how firmly the Mauerlat is installed.

  Therefore, it is necessary to take seriously the fastening of the Mauerlat to the bearing support.

  

  Mauerlat installation

  Sill

  After the Mauerlat has dried (after 5 days), the installation of the bed is marked on the Mauerlat beam: its axis should be with the same indentation on each side of the Mauerlat beam. The bed is attached to a two-layer waterproofing layer anchor bolts. To the wall from the inside, the bed should be fixed with twists of wire or staples. Next, markup is made for installing the rafters.

  

  Installation of a gable roof truss system

  The anchor points of the layered rafters are the walls and racks inside the frame. The rafters are mounted with hinged attachment points. When using sliders for fastening, a slight lowering of the roof frame is ensured in the first years of the roof's service life.

  This installation method is necessary to prevent distortion, as in the early years the building settles a little.

  Rafter beams should be fixed either by installing them in prepared grooves and strengthened with fasteners, or by attaching plank linings.

  

  Installation of rafters

  ridge knot

  The rafters are joined end-to-end, cutting off the edge of the bar so that the angle when connecting opposite beams corresponds to the angle of the slope. Hammer the rafters under the ridge with nails. A variant is possible in which the beams are connected by bolts, a nail or a hairpin, that is, they overlap.

  If necessary (if provided by the project), a cut is made in roof beams for fastening the ridge beam (run).

  

  ridge knot

  Racks

  Racks are attached with a short span - in the center, on the sides and center - with a wider roof base. Fastening is carried out vertically from the ridge to the inner wall.

  

  Run

  Run - a connecting beam for fixing rafter legs. Fastens with bolts or brackets to the rack.

  

  Filly installation

  The final step in the installation of the layered system is the installation of filly with a short length of rafter legs for overhang. To install the visor, it is necessary to install additional small rafter boards.

  

  

  Installation of a rafter system with layered rafters

  Do-it-yourself gable roof truss system: installation with hanging rafters
  

  truss system, equipped with hanging rafters, is a triangular structure, where the sides are rafters, and the base is a puff connected to the lower heels of the rafters.

  Installation of a hanging-type truss frame can do without installing a Mauerlat: a board that is fixed on a two-layer waterproofing can replace it.

  If the structure has a large span, then struts, headstocks, crossbars are attached to it.

  Racks in the hanging system are not provided.

  Puffs

  The puff is the longest beam of the roof frame. To prevent it from sagging, it is necessary to fasten headstock - boards that are attached to the top of the structure on one side, and to the puff - on the other. Fasten with bolts or overlays made of wood. The slack can be adjusted using the threaded collars.

  

  The device of the truss system

  Installation of strut beams

  The headstock can be supplemented with strut beams, forming a rhombus, where two struts are the lower sides, and the rafters are the upper ones, the upper corner is the ridge. Thus, the struts rest against the headstock, distributing the load.

  

  Strut beams

  rafters

  Rafters of a hanging structure are mounted like a layered one. When installing attics, the puff is installed closer to the ridge, providing more space under the ceiling. The tightening in this case is fastened by cutting with bolts.

  ATTENTION!

  When installing a hanging system, a prerequisite for installation is the accuracy of calculations and the strength of the rafters and puffs.

  The presence of errors leads to the displacement of the axes of the elements of the system, which provides a distortion of the structure.

  How to install rafters for a gable roof will tell you this photo:

  

  Rafter installation

  

  hanging rafters

  How to strengthen the rafters of a gable roof

  It is necessary to reinforce the rafters of a gable roof when the load calculation is incorrect or frame defects are found.

  Strengthening can be done with:

  • Balok, which are installed in order to transfer the load to them;
  • Strut mounting with an inclined mount with an emphasis on lying down;
  • Overlays of double-sided rails;
  • Increase in the section of the rafter beam in the place of supports on the strut by applying planking from boards with nails or bolts;
  • board wall, which are attached to the rafters in places where snow is expected to accumulate to increase the bearing capacity of the rafters.

  You can resort to strengthening the Mauerlat beam and the base roof beam. Due high humidity and reduced ventilation, these parts of the frame are more prone to decay, therefore, when arranging the roof special attention needs to be paid

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  When building private households, the projects of houses with a gable roof are considered the most popular, they can be seen in the photo. The design of such roofs is simple compared to hip roofs (they are also called hip roofs). To create a gable roof frame, use wooden beams and boards, the small weight of which allows you to build a truss system with your own hands.

  Elements of gable roofs

  The design of a gable roof includes the following elements:

  • rafters . They consist of inclined struts and vertically arranged racks;
  • rafter leg . For its manufacture, boards with a section of 100x150 or 50x150 millimeters are needed. With the help of rafter legs, a triangular contour of a gable roof is formed. The loads resulting from weather conditions and the weight of the roofing are transferred by the rafter legs to the Mauerlat, and that to the load-bearing walls of the building. When installing a gable roof at home, the installation step of the rafter legs should be at least 60 centimeters, and a maximum of 120 centimeters. The heavier the roofing, the more often they should be installed;
  • struts . Such an element from the trimming of the board is mounted at a certain angle and thereby transfers the load to the load-bearing elements down from the rafter legs. Rafters, several struts and tightening together are the components of the truss truss, which withstands loads and transfers them in the presence of wide spans to the walls;
  • racks . They are vertical rafter elements that transfer the load from the roof ridge to the load-bearing internal walls of buildings. They are made from a bar with a section of 150x150 or 100x100 millimeters;
    

    
    

  • Mauerlat . That's what they call wooden beam, which is installed and fixed on load-bearing walls on threaded rods or on anchors built into the surface. necessary to transfer loads from rafter legs to load-bearing walls. As a manufacturing material, a bar made of coniferous lumber and having a square section measuring 150x150 or 100x100 millimeters is used. Mauerlat beams located on opposite walls should be parallel so that the dimensions of the rafter legs are the same length;
  • skate . This horizontally located element is necessary for connecting the slopes in their upper part. It is formed by connecting the rafter legs at the top point when a gable roof is being installed;
  • filly . They are used if the length of the rafter legs is not enough to create an overhang on the roof. they are part of a board that has a smaller section than the boards used in the manufacture of rafter legs. The installation of a gable roof can be greatly facilitated if this element is used, since then legs of a shorter length are made for the rafter structure;
  • sill . It is a horizontally fixed beam with a section of 150x150 or 100x100 millimeters. It is located on the inner load-bearing wall and its functions include the distribution of loads from the roof racks after;
  • puff. This is one of the elements of a hanging truss structure, which with rafter legs forms a geometric figure - a triangle - and thus helps them stay in place, and not move apart;
  • eaves . It is necessary to protect the walls from getting wet as a result of rainfall, its outer edge must protrude at least 40 centimeters;
    

    
    

  • crate . The device of a gable roof involves the installation of roofing material, for its installation it is necessary to make a crate. To do this, bars or slats are attached to the rafter legs perpendicular to their direction. Due to the presence of the crate, the load from natural phenomena and the own weight of the roof is evenly distributed on the rafter legs. Also, the crate, which can be solid or sparse, fastens the legs of the rafters into a single one. For soft roof, for example, from bituminous tiles, this element is made from sheets of moisture-resistant plywood.

  The roof of the house is created using lumber from coniferous wood, and so that they do not become unusable due to decay during operation, before building a gable roof, they are first treated with antiseptic compounds.

  Rafter systems: their types and differences

  Rafter systems are of two types: hanging and layered.

  
  

  Hanging rafters, together with floor beams, are used as puffs for building an attic when a gable roof of a house is being built with your own hands (read: ""). In addition to the lower puff, an upper puff is also required at a distance of at least 50 centimeters from the ridge. Hanging truss systems are created when the distance between two outer walls is no more than 10 meters, and there is no internal load-bearing wall dividing the interior of the building into two halves.

  Laminated rafters are installed when there is a support beam that transfers the weight of the roof from the ridge to the load-bearing wall located in the middle between the outer walls of the house. If instead of a bearing inner wall there are columns, different types rafters alternate. Layered rafters will rest on the columns, and they will be mounted between the columns.

  Installation of gable roof rafters, detailed video:

  
  

  Features of creating a gable roof

  For competent construction, drawings of a gable roof and design documentation are used, in which all its dimensions are indicated (in more detail: "").

  When the walls of the house are built of logs or timber, the upper timber performs the function of the Mauerlat. But, if the walls of the building are made of brick, for attaching the Mauerlat to the supporting base before the gable or hipped roof, at least 10 mm metal threaded rods are mounted in the masonry and bolts with washers are used. When performing, an interval of 1-1.5 meters is observed between adjacent fasteners. To avoid wetting the walls, waterproofing is laid from two layers of roofing material.

  
  

  The types of gable roofs are varied, but in any case, the slope of the slopes on them should be 15-20 degrees in areas with strong winds, and where it falls a large number of precipitation, 35-40 degrees, then snow and water will quickly roll off the roof surface. These nuances must be taken into account even before.

  
  

  When layered rafters are used, first of all, a bed is installed, and supports are mounted on it, on which a ridge beam is placed. To fix the structure, jibs are used. Then, the rafter legs are mounted on the ridge beam, while their length should be slightly longer than necessary, so that after twisting the two rafters together, the protruding ends can be cut off. The use of this technology can significantly speed up the construction of a gable roof.

  After the installation of the rafter system is completed, the gables and the overhang are sewn up and the installation of the roofing begins. To purchase material, you need to know how to calculate the area of ​​\u200b\u200ba gable roof and thus not be mistaken with its quantity. To do this, determine the area of ​​\u200b\u200beach of the two slopes by multiplying its length (height) by the width (length of the ridge). Note that it is very important to initially correctly calculate .