Rafter installation. Types of rafters and their application

The basis of a beautiful and reliable roof is solid construction truss system. It is important to mount it so that it serves long years, especially in difficult places adhering to the walls of the building, chimneys and pipes of the ventilation system. Depending on the weight of snow, wind load and the severity of the roof, it is necessary to choose the correct pitch of the rafters and the layout of the articulation nodes individual elements truss group. We will consider options for attaching parts of the structure to floor beams and ridges, ways to increase the load capacity of rafter legs and step-by-step installation of trusses and a complex roof as a whole.

The device of the truss system

The construction of the roof is the final stage in the construction of the house, it determines the degree of protection of the building from atmospheric influences and the appearance of the entire building as a whole. The roof frame, on which the roof and insulation are mounted, is called the truss system. The device of the rafter group depends on the type of roof and its complexity, on climatic conditions and on the purpose of the attic. It is mounted on a Mauerlat, fixed on the walls of the house along the perimeter, and consists of the following elements:

• floor beam or puff - a horizontal beam based on a Mauerlat;
• hanging or layered rafter legs, which are attached at the bottom to a puff or Mauerlat, and at the top they are connected and form a ridge;
• run - a beam connecting the trusses of the truss group;

  Depending on the type and size of the roof, truss systems are layered, hanging or combined, but their main elements are largely the same.

• racks, crossbars, struts and fights are auxiliary elements, which are necessary to give strength to the rafters and the entire roof structure;
• jockeys - used on hip roofs and are shortened rafters;

  The diagonal rafters of the hip roof are fastened with sprenels and trusses to ensure even distribution of the load.

• sprengels - designed to give strength to the diagonal rafters of the hip roof;
• filly - are used to lengthen the rafters and sprigs and form a cornice overhang;
• frontal boards - are attached to vertically cut rafters or filly and serve for mounting droppers, windshields and brackets of the drainage system;
• counter-lattice - mounted on the rafters and used to create a ventilation gap between the waterproofing layer and the roofing material;
• crate - stuffed perpendicular to the counter-crate and serves for fastening roofing material.

More complex types roofs are formed from a combination of pitched, hipped and hip types, their truss system is also assembled from the described elements.

The basis of any system of rafters and trusses is a rigid triangular connection, which gives strength to the roof structure and allows it to withstand the weight of snow and wind.

Rafter device options

The rafter system of any kind is designed to create inclined pitched surfaces from which precipitation flows down without accumulating on the roof. In addition, the sloped surface better resists multidirectional wind loads. When installing a truss system, the following types of rafters can be used:

From these types of rafters are assembled different types roofs Consider the most popular device options pitched systems different configuration.

Shed roofs are used in construction country houses, garages, bathhouses and utility rooms. Such roofs are made using the simplest truss system, which can become more complicated with increasing slope length. If the distance between the walls of the building is more than 4.5 m, then the rafter legs are reinforced with struts. For spans of more than 6 m, it is necessary to use two rafter legs on each side or install an additional vertical stand with symmetrical slopes.

The choice of the design of a single-pitched truss system depends on the length of the slope, while the use of composite beams is allowed

As the length of the slope increases, the design of the truss system becomes more complicated with rigid triangular elements and contractions, which gives it additional strength.

Based on the experience of the author of this article, for soft roofing materials with small slope angles, it is necessary to use a solid plywood crate with a thickness of 12 mm or more. When sheet roofing material is used, the sheathing step should be reduced to 10 cm, the overlap should be increased to 15 cm, and the joints of the sheets should be additionally sealed.

Gable and broken attic structures

The gable type of roofs, traditional for the entire territory of our country, remains popular today. This is facilitated by the simplicity and reliability of the truss system, as well as the ability to equip a cold or inhabited attic. Usually, gable roof with an attic it is formed by hanging rafters without an average support, and its rigidity is provided by crossbars and side posts, which serve as walls and ceiling of the attic room.

Gable and broken mansard roofs are very popular in suburban construction due to the possibility of equipping an additional living under-roof space

Broken gable roofs are distinguished by the largest volume of the built-in attic, frame system here it is represented by a combination of hanging and layered rafters with different slope angles.

Gable truss systems are characterized by simplicity of design, high strength and minimum consumption building materials, such roofs are often used in budget suburban construction.

Four-pitched rafter systems

Four-pitched roofs are formed by two trapezoidal and two triangular slopes and have a complex structure of the truss system with support frame, on which ordinary and diagonal beams are mounted. The space between the rafter joists is filled with spears, and the truss resting on the corner lintels serve as an additional support for the diagonal legs.

Four-slope truss systems are typical for hip and half-hip roofs, under which you can place a spacious attic room

Four-pitched roofs are perfectly protected from multidirectional gusts of wind and give the building a special chic, but their disadvantage is an expensive and difficult to install truss system.

The basis for the truss system of the half-hip roof is the walls of the building, on which the Mauerlat, girders and longitudinal trusses are located.

The truss group of a semi-hip roof, as a rule, rests on the side and front walls of the building and has a slightly different design with truncated triangular slopes.

The device of the supporting frame of hipped roofs

rafters hipped roofs in the upper part converge at one point and form a multifaceted pyramid. To increase the strength of the connection of the rafter legs, special docking elements, sheathing bars and additional sprigs are used.

The rafters of the tent system converge at the top at one point and are fastened together with ties, in the lower part they are fixed with cuts

Hip roofs give the building a unique look, but differ increased consumption roofing and lumber. Most often they are used on outbuildings, gazebos, and in a truncated version - as bay window roofs.

Multi-gable truss groups

Multi-gable roofs are pitched fragments cut at right angles to each other and forming at the junction internal corners or valleys. The rafters of such a roof have different lengths, and the assembly of this structure requires professional skills, since the size and angle of inclination of the slopes may differ from each other.

The truss system of a multi-gable roof forms eight triangular slopes, at the junction of which there are valleys

Roofs of this type are designed to provide daylight roof space and have a very attractive appearance, but they are quite difficult to mount and insulate.

The passage of ventilation and chimney pipes through the roof sometimes requires the displacement of the rafter legs with a violation of the selected step between them. But if there are pipes of sufficiently large dimensions, combined into one block, this is not enough. It is necessary to cut the rafters at the place where the pipes pass and connect the cut sections with other rafters with bars fixed to the corners. The distance between the pipe and the wooden elements must correspond to a fire gap of 130–150 mm.

rafter system around chimney built taking into account the fire gap, and the cutout is reinforced with additional racks

Next, the trimmed rafters are fastened with the help of vertical racks to puffs or floor beams. Thus, a box is created around the pipe, which does not come into contact with its hot surface and, if necessary, is filled with non-combustible heat-insulating material.

Roofing over old roofing

In service roofing subject to natural wear and tear. If there is no deformation of the old truss system and you are convinced that it will last for a long time, then repairs can be made quickly and efficiently. When there is no time to dismantle the old roof, you can lay a new coating directly on top of the old roof. To do this, you need to know exactly where the roof beams with a counter-lattice and batten boards.

In my personal opinion based on practical experience, for a new roofing, it is better to choose corrugated board, metal tiles or ondulin, which will not create a large load on the structures of the old roof.

Video: roof replacement without dismantling the old one

The step of the rafter legs when installing the roof

When installing the roof, the rafters are installed at a certain distance from each other. This distance is called a step. Recommendations for choosing the pitch of the truss system are set out in SNiP II-26-76 * "Roofs". The decision must be made taking into account the following parameters:

• roof type;
• the length of the slopes and the angle of inclination;
• type of roofing material;
• section of rafters;
• expected wind and snow load.

The pitch and number of rafters can be selected based on recommendations and adjusted to suit the particular roof. For simple gable roofs with cold attics, the calculation can be made based on the following table.

Table: choice of length, pitch and section of rafters

Mansard and complex roofs require a stronger truss system with more frequent trusses and pitch changes at butt sections with different type stingrays. On such roofs, a beam with a section of 50X150 and 100X200 mm serves as rafters, and the pitch is selected in the range from 60 to 120 cm.

During the construction of roofs with habitable attic room a larger beam is selected, and the rafters are installed more often to increase the strength of the truss

According to the observations of the author of this article, the dimensions have an indirect effect on the choice of step. insulation material. For example, standard width insulation is 60 cm, and the permissible pitch of the rafters with a section of 50X150 mm per pitched roof is in the range from 60 to 120 cm. Prudent owners choose a step multiple of 59 cm in order to mount heat-insulating mats between the rafters tightly and without gaps.

Complex roof construction

Complex roofs include multi-level architectural solutions, which are often distinguished by a mixture of styles, for example, pitched roof bay window or combination hip design with tent element. Even an ordinary multi-gable roof with gables at different levels often has a very complex truss system. The design of such systems is carried out in accordance with the requirements of SP 64.13330.2011 "Wooden structures" and SP 17.13330.2011 "Roofs". To design work professional specialists should be involved, since even a small mistake can lead to marriage and the loss of expensive materials.

Complex roofs should be built only according to ready-made design solutions that contain all the necessary information for the selection of materials and describe the sequence of installation work

The truss system of complex roofs can be divided into simpler components, and at their junctions, valleys, vertical racks and horizontal ridge-type beams can be mounted.

When installing complex truss systems, it is important to ensure that a gap for under-roof ventilation is maintained on all slopes, otherwise condensate will damage the rafters, battens and insulation layer.

Video: complex roofs

The nodes connecting the elements of the truss group perform the function of providing a rigid and durable fastening of parts. The assembly quality of the nodes is subject to increased requirements, since in these connections there is a uniform distribution of the load from the load-bearing elements to the puffs, floor beams and mauerlat. The main types of connections that are used during the installation of rafters include the following nodes:

There are also particularly complex connections, for example, the junction of the diagonal rafters of the hip roof to the purlin and the Mauerlat, or the knot broken roof where five parts of the truss system are connected.

When assembling a sloping roof Special attention should be given to the transition node of the hanging rafters to the layered ones, since five load-bearing elements are connected in them at once

Consider the attachment point for rafters, racks, runs and puffs using the example of a broken line mansard roof. In it, a vertical post is connected with a tie-in to a horizontal run and a puff, then a lower rafter leg is mounted to them, which rests on the puff with the help of a tie-in and a metal bracket. Then the upper truss truss is fastened with ridge ties and also cuts into the puff and is fixed on the bracket. In other nodes of the rafter system, which are used on various types roofs, the same principles for connecting parts are used. As fasteners nails, self-tapping screws, bolts, perforated metal strips and corners of various designs are used.

Installation of the truss system

Before starting the construction of the truss system, it is necessary to carry out preparatory measures to ensure efficient and quick assembly. It is necessary to create a safe environment for work, prepare a place for cutting and making templates, as well as ensure the availability of lumber and fasteners. During the installation process, working drawings and the following tools will be required:

• goniometer (malka), level, construction pencil, cord;
• chain saw for rough cutting and trimming;
• circular saw, jigsaw;
• electric drill, screwdriver;
• hammer, chisels.

Before assembly, it is necessary to make templates of the same type of elements of the truss system and make sure that they fit well and fit well at the installation site.

Roof trusses must be made according to a single template, and this can be done both on the ground and directly at the work site

The final stage preparatory work is cutting lumber in size, impregnating elements with flame retardant and antiseptic compounds and natural drying for at least a day.

In the absence of project documentation for the roof, it is important to choose in advance how to fix the rafter legs in the ridge and cornice parts, as well as Constructive decisions for connecting parts in various docking and other nodes.

The rafters are fastened to the floor beams or puffs in the lower part different ways depending on the complexity of the farm and the length, and therefore the weight of the rafter legs. Rafters with a length of less than 4 m and a cross section of 50X100 mm are sufficient to be attached to the beams with a plank knot or using metal plates, cutting the timber at the required angle and using surfs.

The choice of the method of attaching the rafter legs to the Mauerlat or floor beams depends on the angle of inclination of the slopes, the weight and length of the rafters, as well as on the expected external load

With large values ​​of the length and weight of the rafter legs and the expected snow and wind load, the connection must be made with a frontal cut, single or double tooth. In this case, sub-beam linings are used to ensure a snug fit of the threaded studs. Before installation, it is necessary to create templates that will ensure the correct cutting of materials at the cutting unit and the perfect fit of the elements. To avoid chipping at the edges of the floor beam, it is necessary to cut to a depth of at least 2 cm and at a distance of 1.5 h from the edge of the beam (where h is the height of the beam).

It is important that the holes for the threaded studs are located at an angle of 90 ° to the upper plane of the rafters, as this will ensure a snug fit and secure attachment of the parts to each other without displacement or distortion.

How to make cuts on truss beams

In the process of assembling the truss system, it is necessary to join the elements with different angles tilt. For marking cuts, notches and corner connections are used building levels and goniometric tools, and with mass production templates are made of the same type parts. Washdowns on the rafters can be done in the following sequence.

1. The beam is exposed to the Mauerlat and the ridge run, they are marked according to the level vertical lines and the exact position of the cut.
2. The angle of inclination is fixed on the bevel, and the dimensions of the insert are measured with a tape measure or square.
3. With the help of a square and a goniometer, the measurement results are transferred to the workpieces, after which the cutting angles and the dimensions of the cutting spikes are marked.
4. On the marked workpiece, the necessary cuts are made.

Places for cuts are marked in several stages using a construction pencil and goniometric tool

Diagonal rafters or sprigs come to the joint at different angles in two planes, in this case, using the level, it is marked vertical angle joint, and then the desired angle of contact is fixed with a small one and transferred to the part.

According to the author of the article, cutting the material according to a single sample is not an unnecessary operation, since the time spent on making templates is more than paid off during the installation process, which is significantly accelerated and becomes more rational and of high quality. It is necessary to pay attention to the good condition of the goniometric tool and use only proven specimens.

Do-it-yourself installation of the truss system step by step

Many owners, in order to save money, mount the roof of the house on their own. With some building experience, this decision is fully justified, since even complex roofs it is quite possible to assemble with your own hands, having project documentation. In the absence of a project, you must make a drawing yourself future design with the main parameters and dimensions of the elements of the truss system.

Rafter truss blanks can be assembled on the ground or directly on the roof. Usually a triangle is made from two side beams and a lower puff, all other elements are mounted after the truss is in a vertical position. Each design must be made according to a template made in advance and tested at the installation site. With a significant length and weight of structural elements, assembly is carried out in stages.

Installation is carried out in the following sequence.

1. For threaded rods reinforced belt or the last crown of walls along the perimeter are mounted solid bars mauerlat to ensure even distribution of the load from the truss system to the walls of the building.

   In the houses of their concrete or building blocks, the Mauerlat is installed on studs embedded in the armored belt, in wooden buildings its role is usually played by the last crown of the wall

2. Floor beams or puffs are attached to the Mauerlat with brackets, metal corners or bolts. When using long and massive rafter legs, vertical racks are mounted in the middle of the floor beams, and ridge runs are attached to them.
3. The first blank for the roof truss is installed from one edge of the roof (on the pediment). A tie-in is made on the rafter legs, and they are attached to the Mauerlat, floor beams and ridge run.

   Roof trusses on the gables are installed first

4. The second blank is installed in place of another pediment.
5. Both farms are fixed in vertical position, which is controlled by the level or plumb.
6. Guide cords are pulled between the installed trusses.

   Guide cords are pulled between the truss trusses installed on the gables to control the correct position of the intermediate elements

7. Intermediate truss structures are installed with the selected step. All of them should be aligned vertically and along the stretched cords.
8. Ridge and additional horizontal runs are mounted (if they are provided for by the design).
9. The rafters are reinforced with crossbars, racks and other elements provided for by the project.

   After installing all roof trusses, horizontal girders and additional reinforcing elements are mounted

10. On hip roofs, ordinary rafters are first installed, based on a ridge run and a mauerlat, and then diagonal rafters and rafters are alternately placed.
11. With the help of gable and frontal boards, overhangs are formed that protect the walls of the building from precipitation.
12. Attached to the rafters waterproofing film with a sag of no more than 20 mm and bars of a counter-lattice, which provide a ventilation gap between the waterproofing and the roofing. Then a longitudinal crate is laid, which serves as the basis for the roofing.
    

    Installation of a waterproofing film, counter-lattice and lathing completes the assembly of the truss system

Experience shows that with a rafter length of more than 6 m, it is necessary to build them up at the joints using a spike, double-sided pads and using threaded studs or bolts installed in increments of 15 to 20 cm. The joint must be reinforced with additional racks or struts. In 2010, using this technology, the author installed a roof with a length of rafter legs of more than eight meters, so far no deflections or other changes in shape have been found on the slopes.

Complex roofs are mounted starting from the main ones. load-bearing structures on which the truss system is based. Then ordinary and diagonal rafter legs, sprigs and auxiliary elements are installed. In conclusion, different types of fragments are joined together in single structure.

According to the author of this article, who mounted three roofs of varying complexity with his own hands, the installation of the truss system can and should be done by yourself. The first roof was cut and assembled according to the drawing in four days, and on the fifth and sixth day waterproofing, sheathing, frontal boards and roofing material were installed. The second roof took three and a half days, and the third was erected in two days. With the growth of skill and with proper planning of work, the installation of the truss system is significantly accelerated. If you have building experience, then installing a roof with proper quality is not difficult at all. In case of difficulties, it is necessary to involve design engineers or professional builders for advice, who will help in a difficult situation.

Video: device and installation of the truss system

We considered the options for assembling the truss system at the junction with pipes, over old roofs, at the points of contact with the Mauerlat, as well as in the case of complex truss structures. Along the way, we studied some ways to connect elements of trusses and slopes. The roof can be assembled with your own hands, it is important to strictly follow step by step instructions and strictly observe safety precautions, then success will be ensured.

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Installing rafters: 2 simple instructions for doing it yourself

Construction planned roof frame but don't know where to start? I will tell you how the installation of rafters is carried out on houses made of gas silicate blocks and on frame-type buildings. As a result, you will be able to choose the right simple instructions and apply it in the construction of your country house.

Installation of rafters on a brick house

As an example, consider how to independently install a truss system on a gable roof for a suburban brick house. The peculiarity of this roof is that in the attic you can arrange an attic with your own hands.

The facade walls turn into pediments made of the same wall material. This fact will simplify the task, since the roof frame will be built between the gables. In addition, a roof built between brick gables is more stable in terms of wind load.

The peculiarity of this roof frame is that it will be built without timber, but only from boards. The problem of the absence of a beam will be solved by a longitudinal connection of two boards, for example, this will be done when laying down. This approach is due to saving money, since two 200 × 50 mm beams will cost less than a 200 × 100 mm beam.

Construction technology

Illustration	Step-by-step instruction
	Preparation of materials. To assemble the truss system, we will use a board 200 × 50 mm. In addition, you will need fasteners and waterproofing materials. Before work, we impregnate lumber with an antiseptic and dry it.
	Mauerlat installation. In accordance with the previously proposed drawings, we put the power plates on the side bearing walls. Before installing beams, over brickwork we lay out a bituminous substrate. We fasten the Mauerlat to the wall with anchor bolts with a diameter of at least 12 mm. We select a bolt installation step of at least 1.5 m.
	Installation of the bed. Laying the bed on the intermediate wall is carried out according to the same principle as the installation of Mauerlats. The difference is that we lay the bed in two boards, since the distribution of loads on it will be greater than on the outer walls.
	Installation of the ridge run. On the bed, close to the gables, we fasten the extreme vertical racks. So that the racks do not move during installation, we temporarily fix them with diagonal struts. On top of the racks, with the help of perforated metal corners, we fasten a horizontal beam - a ridge run, on which the tops of the rafter legs converge. Following the example of the extreme racks, in the interval between the run and the bed, we install intermediate additional supports in increments of 80 cm.
	Fitting the first rafter. We apply a board installed on the edge to the run and the Mauerlat. On the board at the level of the run and at the level of the Mauerlat, we draw the edges of the notch with one horizontal and one vertical side. As a result, the edge of the overhang of the beam below the Mauerlat should be at least 60 cm. Cut out the corners according to the markings.
	Rafter fit. Following the example of one blank, identical cuts are made on another board. Then the beams are installed on the run and seized with a clamp. By level, we mark a strictly vertical center line, along which we cut the combined boards. The result should be a skate, as shown in the photo.
	Rafter fastening. We fasten the beams combined on the run with perforated metal corners at the bottom and at the top. Besides, ridge knot additionally tighten using a perforated metal plate. All fastenings are carried out on self-tapping screws. For greater reliability, we use colored self-tapping screws, as they are galvanized. Black self-tapping screws are only suitable for temporary installation.
	Rafter installation. On the contrary, the already assembled truss truss, we install the last truss. Between established structures we pull the cords, one at the level of the ridge, the other in the middle and one more closer to the Mauerlat. We install and align the intermediate rafters along the cords.
	Installing puffs. To strengthen the truss trusses at the level of the bed, we fasten horizontal struts, which must go through the edge of the opposite rafters on both sides. We make a puff from a board placed on the edge. We fasten the board to the rack with self-tapping screws, and to the diagonal beams with self-tapping screws and a bolt with a nut through cap washers. We install similar puffs at the bottom of each farm. We cut the side ends of the puffs flush with the surface of the rafters. Subsequently, the installed puffs will be used as floor beams.
	Trimming overhangs. We mark each overhang so that there is a recess for fastening the eaves board and a vertical cut for installing a wind board. You can take measurements on each board separately, or you can make one template and go around all the overhangs with it and evenly transfer the markup According to the markings made, we cut off all the overhangs with a miter saw.

Installation of rafters on a frame house

I offer another example where the installation of the truss system will be carried out on frame house 6×6. At the heart of the house, a wooden lattice frame was used for subsequent filling with insulation and sheathing with slab materials.

Since the construction will be carried out on a frame house, the requirement for rafters, as well as for the selection of roofing material, is one - this is a small weight without compromising the strength of the structure. Therefore, during construction, it will be correct to use a dry board 200 × 50 made of wood conifers.

Assembly technology

Illustrations	Description of the main stages
	Installation of floor beams. Across top harness walls are installed laid on the edge of the board - logs. The optimal installation step, which ensures high strength in combination with an acceptable floor weight, is 35-40 cm. Laid floor beams in the structure frame house will be the basis of the farms.
	Rack mounting. The rack is assembled from two boards folded flat. One board is 2.4 m long, and the other is shorter - 2.2 m. The protrusion resulting from the difference in length will be used as a stop for the run. We install the rack according to the level and support the struts during the installation of the entire structure. The dimensions of the stand are approximate, and you can adjust them, taking into account the selected angle of inclination of the slopes.
	Installation of the remaining racks and run. Following the example of the first rack, an extreme rack is installed. The run is attached so that the horizontal beam lies on the steps. The run-out on the extreme racks is provided for the subsequent sheathing of the pediment. Intermediate supports are installed between the extreme racks.
	Mounting the junction of the rafters to the beams. One end of the rafters is laid on the run, while the other end is laid on bottom harness. The edge of the rafter is fastened with nails directly into the floor beam. Thus, we carry out the installation of two extreme boards, we stretch a cord between them and install intermediate beams along the cord.
	Mounting the ridge knot. Docking top edges rafters on a preliminary washed down end to end. FROM inside the junction of the rafters is fastened with a wooden lining, as shown in the photo. The trims can be cut from scraps that you will have left when assembling the uprights. The overlay and the ridge knot are connected with nails, plus a metal mounting bracket fixed on self-tapping screws is installed at the junction of the overlay to the run.

Summing up

Now you know how to properly install rafters for roofs with two slopes. If you still have questions about the proposed instructions, you can ask them in the comments to this article.

If you want to express gratitude, add a clarification or objection, ask the author something - add a comment or say thanks!

Installation of rafters is one of the key stages in the construction of the roof. To prevent the rafter system from deforming and collapsing under high loads during operation, the rafters must be properly fixed.

Calculation of the pitch of the rafters

When designing the truss system, special attention is paid to this issue. The strength characteristics of the roofing system depend on the section of the rafters and the step of their installation.

The pitch of the rafters is the distance between adjacent rafter legs. The minimum pitch of the rafters is 60 cm, the maximum is more than 1 meter. A simplified version of the calculation of the pitch of the rafters involves the use of a table:

The length of the slope along the eaves must be divided by the rafter step selected in the table, then add one to the resulting value and round up to an integer. The resulting result means required amount rafter legs per slope. Then the length of the slope along the eaves should be divided by the calculated number of rafter legs - the final number corresponds to the value of the center distance between the rafters.

This calculation method is general, it does not take into account the specifics of roofing and the type of insulation used. If it is planned to lay a roll or slab heat insulator, it is recommended to adjust the pitch of the rafters to the size of the material. It should be noted that the width of the cotton insulation should be 1-1.5 cm more than the span between the rafters.

When determining how far to put the rafters, you should also pay attention to the recommendations for installing the selected roofing.

Material preparation

Do-it-yourself installation of rafters requires not only knowledge of the process technology, but also the correct preparation of the wooden elements of the system for installation. The rafters are made from edged board or timber, the section of lumber is selected at the design stage of the roof. The tree should not have cracks, wormholes or other damage.

Rafter legs should be made of well-dried softwood to prevent their deformation.

Wooden elements must be treated with fire retardant and bioprotective compounds. Before proceeding with the installation, it is necessary to determine the method of attaching the rafters to the Mauerlat or beams, with a view ridge connection. In accordance with the project, metal and wooden fasteners are selected, including:

• plates (made of metal or wood);
• bolts or studs with nuts and wide washers;
• nails, self-tapping screws, staples, etc.;
• wire rod.

Types of rafters and features of their installation

When erecting the roof of a house, hanging or layered rafters are used. In some cases, a combination of both may be used. Hanging ones rely only on the walls of the building, and layered ones require the installation of additional supporting structures, so this option is primarily used if there is an average load-bearing wall or support pillars inside the building box.

Sloped rafters bottom rest against the Mauerlat, respectively, the walls of the structure must have sufficient width for the installation of a special supporting structure made of timber with a section of 150 × 150 mm. Top part layered rafters rests on a ridge run. Thus, the installation requires the installation of a run, for which middle wall or poles should be mounted racks.

Hanging rafters rest only on the walls. This design can be mounted both on the Mauerlat and on thin walls without laying the Mauerlat. In this case, the floor beams protruding beyond the plane of the wall on both sides of the building serve as a support for the lower part of the legs. Hanging rafters are connected by a jumper (puff, crossbar) which relieves bursting forces. When overlapping large runs, truss trusses are reinforced additional elements to enhance structural rigidity. When installing hanging rafters on a Mauerlat, a low puff can serve as a floor beam.

Before you put the rafters, you need to mount the scaffolding. This makes it possible to provide the necessary safety and convenience of work.

Installation of the upper ends of the rafters

When choosing how to install rafters, it is important to evaluate the complexity of the work and the weight of the truss structures. If the assembled farm has a relatively small weight, or it is possible to use lifting equipment, then the structures are easier to assemble on the ground, and then lift and mount on the roof. If the elements of the system are heavy and have to be lifted manually, then the trusses are assembled on the roof. The installation technology of roof trusses is described in the video instructions.

The connection of the upper ends of the rafters can be performed in different ways. First of all, this is a butt mount. On the opposite rafter legs, cuts are made under right angle. Then the rafters are docked with the resulting ends and fastened to two nails. The connection is additionally reinforced with a wooden or metal lining.

The overlap of the rafter legs is carried out using bolts or studs with wide washers and nuts. In this case, the rafters are in contact with planes.

If the rafter system is mounted on wooden house with gables made of timber or logs, it is required to put the rafters on the walls using sliding fasteners in order to avoid deformation of the roof during shrinkage of the structure. Accordingly, in the ridge part, the rafters must be connected in a special way: the rafter legs must be located with a gap, and they are fastened with a special movable connecting element from metal.

In the presence of a ridge beam, installation of truss trusses on the ground is not required - the rafter legs are installed one at a time and attached to the ridge run.

The ridge run must be located strictly horizontally so that the rafter system evenly distributes the load experienced by the roof.

Methods for installing rafters on walls

The lower ends of the rafters are attached to beams or mauerlats. Hanging rafter trusses mounted according to the template rise to the roof. First of all, extreme farms are installed. In the tightening, two or three holes are required to attach the rafters to the beams laid on the upper crown of the log house.

If a hanging rafters mounted on stone building, it is required to use special fasteners - the so-called "ruff", made of durable steel. This fastener is driven into every fourth row of brickwork. With the help of loops extending from the ruff, you can fix the beams. It is recommended to use a solid beam as a Mauerlat - in this case, the load will be evenly transferred to the walls.

On buildings made of brick or other material that is not prone to shrinkage, the rafters should be fixed rigidly. To do this, a cutout is made in the rafter leg, Bottom part which should lie firmly on the Mauerlat. The rafter is fixed with three nails (two are driven in on both sides at an angle, and the third is vertically on top) and tied with wire. A connection can also be used with the help of corners and a support bar that prevents the rafters from shifting.

Proper installation of rafters implies the implementation of a fire break in the place where the roof passes through chimney. If, during its arrangement, the installation of a special rafter system is provided, this should be taken into account when installing a shortened rafter leg (from the Mauerlat to the chimney structure). Between structural elements and pipe, the distance must be at least 130 mm.

During the construction of private houses, the roof is most often made gable. There are reasons for this. First, it is reliable. Handles wind and snow loads well. The second - it is compatible with any roofing. The third is relatively inexpensive. The fourth is a simple design that is difficult to spoil. Fifth - it looks attractive. All this, and more gable roof it is built with its own hands without the presence of special knowledge, determines its popularity.

Do-it-yourself assembled gable roof ready for installation of roofing

Step-by-step installation of a gable roof

As you saw above, there are a lot of truss systems. Accordingly, when assembling each has its own characteristics, but in general the order is the same. It is necessary to say about the general step: pre-drying and processing of wood. This step is required if you bought fresh lumber, not dried.

The use of raw wood in the construction of the roof natural humidity will lead to problems: the beams will bend, they will dry out, the geometry will change. All this will lead to tension points and at the slightest sign of overload (lots of snow, strong wind or rain) negative processes will begin. Their elimination is a complex and costly undertaking. Therefore, either buy dry wood (no more than 20%, ideally chamber drying 8-12%), or buy material a couple of months in advance, put it in ventilated piles. After that, treat with the necessary impregnations (from fungal attack and to reduce flammability) and only after that use it in the installation of the truss system.

Timber must be dried in ventilated stacks. To do this, they are laid in short pieces of boards. They are placed a meter from the edges and further through the meter. Spacers must be installed under the bottom

We will talk about the main stages of assembly, about how to make a gable roof with your own hands in this section.

Mauerlat

The assembly of the gable roof truss system begins with the installation of the Mauerlat. It must be set strictly horizontally, therefore, before starting installation, the horizontalness of the wall to which it is attached is carefully checked, if necessary, it is leveled cement mortar. You can continue work after the solution gains 50% strength.

Depending on the system, this is a beam with a section of 150 * 150 mm or a board with dimensions of 50 * 150 mm. It is attached to top row wall masonry. If the house is wooden, its role is played by the upper crown. If the walls are made of light building blocks - foam concrete or aerated concrete and others - their rigidity is not enough to redistribute the load. In this case, a reinforced concrete belt is made over the last row of masonry, into which embedded fasteners are embedded - wire or studs. A bar or board is then mounted on them.

There are several ways to connect walls and Mauerlat:

• In the masonry (in the reinforced concrete belt) a smooth rolled wire of large diameter is fixed (two ends stick up). The board is then rendered in necessary places holes through which the wire is threaded. She then twists and bends.
• Studs with a diameter of at least 12 mm are immured in the wall. Under them, holes are made in the Mauerlat, a beam / board is placed) and tightened with nuts with wide washers.
• Aligning the beam or board along the outer or inner edge of the wall, take a drill with a diameter of 12 mm, make holes for the anchor bolts. They (the same diameter of 12 mm) are hammered to the very hat, then tightened with a key.

The distance between the studs (wire) should not be more than 120 cm. Cut-off waterproofing must be laid on the wall (belt) under the Mauerlat. It can be rolled roofing felt or waterproofing in two layers, it can be smeared with bituminous mastic.

Rafter installation

There are more than a dozen types of gable roof truss systems. First of all, you need to choose what yours will look like. Further, in order to make it easier to work, a template is made from thin boards for all cuts, cuts and other similar details. To do this, you may need to assemble the first form on the roof, and then make templates for the finished one.

The assembly order depends on the type of truss system. If the rafters are layered, they are installed gradually, assembling from the elements directly on the roof. In this case, it is convenient if the beams of the ceiling are laid and, if possible, the draft flooring of the attic or attic.

In systems with hanging rafters, a farm is assembled on the ground - a ready-made triangle of puffs and rafter legs with all the required struts, racks. The required number of farms is assembled at once. Then they are lifted to the roof, placed vertically there and attached to the Mauerlat.

On the one hand, this is convenient - it is easier to work on the ground, with a high assembly speed, the accuracy is high: one farm is not much different from the other, which simplifies the procedure. But it can be difficult to raise finished trusses, especially for large buildings. To make this easier, two inclined boards are installed, which at one end rest against the ground, and the other sticks out a little above the wall. Farms are brought closer to this “lift”, one by one they are installed below, ropes are tied and pulled along the boards to the roof. In the absence of a winch or crane, this is the most acceptable method.

The assembly of rafters requires certain knowledge: how and in what order to mount them, how to mark and make cuts. See the video for the assembly of one of the schemes with a headstock.

Assembly order of the truss system

Everything, the do-it-yourself gable roof is assembled and ready for installation of roofing material.

The process of installing the rafters itself raises enough questions, but there are many ways and it is impossible to tell about them all. See one of them in the video. The system is large and went up to the roof in parts, and there it was already assembled into a single structure. For big houses it's comfortable.

Features of the installation of the truss system of a wooden house

difference wooden houses consists in the fact that the frame shrinks, and this leads to a change in the geometry of the truss system. If the elements are fixed rigidly, the roof may fall apart. Therefore, the mounts are made floating. There are special sliding fasteners, which in this case attach the rafters to the upper crown and to the girders, if any (see photo).

In order for the rafter to move freely during shrinkage, its long part is fixed strictly parallel to its edge, and the support is placed strictly perpendicular. If necessary, a platform is cut out under it. Mark the mount so that the hook is in the lowest position or near it. They are mounted on special self-tapping screws that come with the kit (ordinary ones do not fit). If the installation is done on a log, so that the rafter leg does not slip along it, a semicircular hole is cut out in the lower part, on which it will rest.

Such fasteners are sold on any construction market, it is called "slippery". How to attach the slippery to the beam, see the video.

Video on assembling and installing a gable roof truss system

Building a gable roof with your own hands is not easy: there are a lot of subtleties and nuances, there are different ways fixings, extensions. Describing them in words is a thankless job. This is the case when it is better to see. Below is a selection of videos that you might find useful.

Video report on how a gable roof is made

The story of the owner of the house about the stages of construction. There are interesting technical points that may be useful.

Two types of rafter connection: rigid and sliding

Video about the two most problematic types of connections.

How to determine the angle of the rafters

Full video report on the assembly of the truss system

This movie is just under an hour long, but the entire process is shown from start to finish with plenty of detail. The roof is placed on, but when installed on buildings of a different type (except for wooden houses), there is no difference.

It is better to entrust the installation of rafters to specialists, the roof is not the element of the building with which you can experiment. However, it is necessary to know the basics and features of how to put rafters on a house, if only in order to control the quality of work and be able to build a simple truss structure.

How to properly put the rafters on the house - let's deal with the terms!

If most people more or less imagine what a rafter is, then a problem may arise with the rest of the terms found in the case of a roofer. Mauerlat, crossbar, bed, stand, brace, run - it is unlikely to do without the help of specialized literature or an experienced builder! However, if you are reading this article, then you can do without them.

• Mauerlat is traditionally wooden beam with a section of 15 * 15 cm, which acts as an extreme lower support for the rafters, distributing the load from the joining points of the rafters to the entire upper wall area. Recently, instead of wood, metal is often used; for Mauerlats, these are channels and I-beams. Mauerlat is installed with a slight indent from the outer edge of the wall and fixed. To prevent rotting and corrosion from below, the beams are insulated with roofing felt or other waterproof material. It is with this element that the installation of rafters often begins.
• Lezhen - additional beam to distribute the load from the rafters along the entire perimeter of the walls. They differ from Mauerlats in that the beds are installed inside complex truss structures, that is, they are not obligatory element roofs, but only as an addition in the right cases.
• Rack - vertical beam, which reinforces the truss structure from the inside. In turn, girders are installed on the racks, which are supported by struts - inclined beams that support horizontal elements and counteract compression or skew of the structure.
• Run - a horizontal beam that crosses the rafters perpendicularly along the entire length of the roof. Three types of purlins can be distinguished in the roof structure - ridge purlins (on which the rafters converge at the top of the roof), side purlins and Mauerlats, which are described above.
• Crossbar - a beam that is installed between the rafter legs, increasing the strength of the structure and its stability. Usually the cross section of the crossbars is 10 * 15 cm.
• Rafter legs or rafters - beams on which the roofing is directly installed. Rafter is also a common name for the whole roof structure. For this element, a bar with a section of 10 * 15 cm is used. For the manufacture of a plank truss system, it is used pine board with a section of 50 * 150 mm or 60 * 200 mm.

Before installing the elements, it is necessary to accurately calculate their number, as well as take into account the possible loads on the rafters: they can be one when installing slate, others for tiles and third for.

For example, shed roof, built from a minimum number of elements, can easily withstand sheets of metal or slate, while under the tiles, over time, the rafters can deform, bend, which means that you will need to additionally strengthen the structure with racks or struts, and also use beams with a large section.

How to install the rafters - layered or hanging?

Rafter structures are divided into two groups - layered and hanging. Hanging rafters are usually built on the roofs of buildings without internal load-bearing walls. Hanging structure it rests on a ridge run and power plates, and at the bottom it is fastened with puffs, which prevent the rafters from moving apart under the influence of a load. It should be noted that much more timber is spent on hanging rafters, since this ensures their stability. You can save wood on plank rafters, since log options take 15-20% more timber.

Sloped rafters are installed on those buildings that have load-bearing walls inside, since this type requires a minimum of three support points. Layered elements can block the span maximum length up to 6.5 meters. If there is a need to increase the width of the covered area, then this can be easily achieved by installing additional supports: with one additional riser, the width can be increased to 12 meters, and with two - up to 15!

Depending on the section of the beams that are used for the manufacture of rafter legs, the spacing of the rafters varies from 0.8 to 1.2 m. The construction of the rafter frame, including runs, racks and struts, provides special stability to the rafter legs. This type is most often used in private construction, since on the one hand it turns out strong and reliable roof, and on the other hand, layered rafters are very economical- wood on them, in comparison with hanging ones, is needed many times less. Quite often, a roof is constructed by combining both types.

How to put rafters on the roof - what for?

To begin with, guided by detailed instructions, as given in a separate article, calculate how much material you need. Before installing the elements of the truss structure, they must be treated with compounds against fungi, insects and flame retardants that prevent ignition. Having spent on these compositions before putting the rafters on the roof, you will extend their service life by decades.

How to put rafters on the roof - step by step diagram

Step 1: Installing Mauerlats

The most important connection in the layered versions is the place where the rafter leg rests on the Mauerlat. It is with the fixing of the Mauerlat that the installation begins. To do this, metal pins are pre-concreted in the walls, which go deep into the walls by at least 40 cm. Wire twists with a diameter of at least 6 mm will also be suitable for the same purposes.

Step 2: Making the layout

Raise up two beams, which will be rafter legs. Cut notches on the left and right leg for emphasis on the Mauerlats, do not forget to mark for yourself which side of which beam belongs to. Install the bars, joining them at the top to make marks for the notches at the top. Notches are needed in order to make a connection with an emphasis, and not an overlap - this is considered extremely unreliable even with strong nailing.