Rafters from boards: how to make a roof rafter system yourself? Strong roof: roof rafter system and its types Series for the nodes of the pitched wooden rafter system.

The rafter system is the basis of the roof; the reliability and strength of the roof, its ability to withstand precipitation and wind depend on it. The design of the rafter system is determined by the shape of the roof and the features of the layout of the house, as well as the materials used. The do-it-yourself rafter system is usually made of wood, but other materials can also be used, for example, a metal profile.

Types of rafters and their application

The choice of a rafter system is a crucial step that requires knowledge of the design of each type of roof. Rafters can be:

Roof rafters supported by a ridge girder and a Mauerlat. They are used in the construction of a single-pitched, simple gable roof, as well as one of the elements of a hip and sloping mansard roof.
Sliding rafters are a type of layered rafters used for wooden structures that give high shrinkage. Their difference is the sliding fastening of the rafters to the Mauerlat, which makes it possible to compensate for the shrinkage of the walls without deforming the roof.
Hanging rafters - a system of rafters strapped with crossbars or ties, usually used in the construction of a simple gable roof, as well as as the upper rafters of a mansard roof. In the hanging rafter system, the ridge girder is absent, and in the upper part the symmetrical rafter legs rest directly on each other.
Oblique rafters, otherwise called corner or diagonal. They are used to make a three-pitched or four-pitched roof, as well as for roofs with complex geometry.

Elements of the rafter system

Any rafters are designed to distribute and transfer the load of the roof to the walls of the house. The main elements on which the rafters rest are:

Mauerlat - a bar fixed on the upper plane of the walls along the perimeter of the entire house;
Legs - support beams laid on internal load-bearing partitions or columns;
Top floor beams;
Racks and supports;
Girders - horizontal support elements laid along the roof axis on the posts.

The roof truss consists of the following elements:

Rafter legs - boards or beams that form the contour of the roof and are laid with a certain pitch;
Puffs or crossbars are horizontal elements that tighten the paired rafter legs together;
Braces - supports set at an angle and supporting the rafter legs;
Fillets - boards fixed at the lower end of the rafters and forming the overhangs of the roof;

Narozhniki are short rafters supported by diagonal rafters in a hip roof.

All these elements in private construction are usually made of wood - beams or coniferous boards, dried in a natural way. The tree is impregnated with an antiseptic, which makes it possible to extend its service life. The thickness and section of the elements is determined by calculation.

Technology for performing layered rafters

Before starting construction, you need to sketch the roof and calculate its dimensions. The section and pitch of the rafters, as well as the need to install additional supports and struts, are also determined by calculation.
Support elements are laid and exposed: Mauerlat, beds and floor beams, racks, ridge and intermediate runs. These operations are described in detail in the articles on various types of roofs:
A rafter template is made. To do this, take a board with a width corresponding to the calculated length of the rafters, with the same width, but with a smaller thickness - it is lighter and easier to fit exactly in place. The board is applied to the installation site of the extreme rafter with one end to the ridge girder, the other to the Mauerlat.
In the upper part of the template, mark the upper cut. The shape of the saw should be such that the board lies on the ridge girder and at the same time fits snugly against the opposite rafter. The depth of the cut should be no more than 1/3 of the board width.
After cutting the upper cut, the template is again applied in place and the lower cut is marked - it should rest on the Mauerlat, without leaving large gaps. The end of the template is sawed off at an angle so that the cut is in the vertical plane.
The resulting template is applied at the installation site of all rafter legs, checking whether a fit will be needed in place. If the template fits perfectly (which rarely happens), you can immediately make the required number of rafter legs. If you need to adjust the bottom cut, then only the upper part of each rafter is cut out according to the templates, and the bottom cut is made in place each time.
The rafters are placed with a set calculation step. It usually ranges from 50 to 120 cm and depends on the type of roof covering, namely on its severity, and on the expected snow load. The heaviest coatings are slate and ceramic tiles, but these are rarely used today. More often, the choice is made in favor of more modern, lightweight and reliable materials: metal tiles, ondulin, soft roofing. For them, the pitch of the rafters can be chosen about 100 cm without performing complex calculations.
First, the rafters are installed from the side of the gables. The rafter leg is supported on the ridge girder and the Mauerlat and fixed on two 100-150 mm nails at each attachment point. Having installed the rafter pair, they additionally fasten it: in the upper part with the help of metal plates and self-tapping screws on one side and corners with a stiffener on the other, in the lower part - with brackets or also on corners.
After installing the rafters, a twine is pulled between them from both gables of the roof and the remaining rafters are aligned along it. The rafters are fastened in the same way.
Install struts, if required by the results of the calculation. The braces are made of the same material as the rafters. Apply a board of suitable length at the desired angle to the rafter and mark the bottom cut. It is important to take into account what the brace will rely on: on a floor beam or on a bed, the shape of the bottom cut depends on this. After performing the lower cut, the brace is placed in place and the cutting line is marked along the rafters. The prepared strut is placed between the beams and the rafters and fixed with metal plates or corners.

Installation of struts on the roof

Technology of execution of hip diagonal rafters

Since the rafters for the hip roof are installed diagonally, the usual methods of fastening them are not suitable. In addition, the load on the diagonal rafters is much higher than on the layered or hanging ones, so the material for their implementation must have a larger section. You can use a beam with a thickness of 100 mm, but practice shows that it is more convenient to make these rafters from two folded and bonded boards of standard thickness.
The diagonal rafters are supported with the upper end on the racks, with the lower end on the Mauerlat bars converging at right angles. They are marked in place, and their main feature is that the cuts are performed not perpendicular to the plane of the board, but at an angle of 45 degrees. When performing rafters from spliced \u200b\u200bboards, first one side is performed with oblique cuts, then the second, in a mirror image.
The boards are pulled together with screws, nails or hairpins. The hip rafters are fixed with pads and screws.

A video will help you better understand the basic techniques for erecting a rafter system with your own hands.

When performing any rafter system with your own hands, it is important to carefully secure all nodes and connections and remember that the roof is the main protection of your house from bad weather. Therefore, it is important not only to make a high-quality frame, but also to choose a suitable one, for example, corrugated board, and lay it correctly.

At the heart of each roof is a large number of beams, rafters, posts and purlins, which are collectively referred to as the rafter system. Over the centuries-old history of the types and methods of its organization, a lot has accumulated, and each has its own characteristics in the construction of nodes and cuts. We will talk in more detail about what the rafter system of a gable roof can be and how the rafters and other elements of the system should be attached.

The structure of the gable roof truss system

In section, the gable roof is a triangle. It consists of two rectangular inclined planes. These two planes are connected at the highest point into a single system by a ridge bar (run).

Now about the components of the system and their purpose:

Mauerlat - a beam that connects the roof and walls of the building, serves as a support for the rafter legs and other elements of the system.
Rafter legs - they form the inclined planes of the roof and are the support for the sheathing under the roofing material.
Ridge girder (bead or ridge) - combines two roof planes.
Tightening is a transverse piece that connects opposite rafter legs. Serves to increase the rigidity of the structure and compensate for bursting loads.
Beds are bars located along the Mauerlat. Redistribute the load from the roof.
Side Girders - Supports the rafter legs.
Racks - transfer the load from the girders to the benches.

Fillets may still be present in the system. These are boards that lengthen the rafter legs to form an overhang. The fact is that to protect the walls and foundation of the house from precipitation, it is desirable that the roof ends as far as possible from the walls. To do this, you can take long rafter legs. But the standard length of lumber of 6 meters is often not enough for this. Ordering a non-standard is very expensive. Therefore, the rafters are simply grown, and the boards with which they do it are called "filly".

There are quite a few constructions of truss systems. First of all, they are divided into two groups - with layered and hanging rafters.

With hanging rafters

These are systems in which the rafter legs rest only on the outer walls without intermediate supports (load-bearing walls). For gable roofs, the maximum span is 9 meters. When installing a vertical support and a system of struts, it can be increased up to 14 meters.

The hanging type of gable roof rafter system is good because in most cases there is no need to install a Mauerlat, and this makes the installation of rafter legs easier: you do not need to make cuts, it is enough to mow the boards. To connect the walls and rafters, a lining is used - a wide board, which is attached to studs, nails, bolts, crossbars. With such a structure, most of the bursting loads are compensated, the effect on the walls is directed vertically downward.

Types of rafter systems with hanging rafters for different spans between load-bearing walls

Gable roof rafter system for small houses

There is a cheap version of the rafter system when it is a triangle (photo below). Such a structure is possible if the distance between the outer walls is no more than 6 meters. For such a rafter system, you can not calculate the angle of inclination: the ridge must be raised above the tightening to a height of at least 1/6 of the span length.

But with this construction, the rafters experience significant bending loads. To compensate for them, either rafters of a larger section are taken or the cutting of the ridge part is made so as to partially neutralize them. To give greater rigidity in the upper part, wooden or metal plates are nailed on both sides, which securely fasten the top of the triangle (also see not the picture).

The photo also shows how to extend the rafter legs to create a roof overhang. A cut is made, which should go beyond the line drawn up from the inner wall. This is necessary in order to displace the notch and reduce the likelihood of breaking the rafter.

Ridge knot and fastening of rafter legs to the backing board with a simple system version

For mansard roofs

The version with the installation of the crossbar is used for. In this case, it is the basis for filing the ceiling of the room below. For reliable operation of this type of system, the crossbar cut must be non-hinged (rigid). The best option is semi-rotten (see the picture below). Otherwise, the roof will become unstable to loads.

Please note that in this scheme there is a Mauerlat, and the rafter legs should extend beyond the walls to increase the stability of the structure. To fix them and dock with the Mauerlat, a cut is made in the form of a triangle. In this case, with an uneven load on the slopes, the roof will be more stable.

With this scheme, almost all the load falls on the rafters, therefore they must be taken of a larger section. Sometimes the raised tie is reinforced with a suspension bracket. This is to prevent it from bending if it supports ceiling sheathing materials. If the tightening is short, it can be secured in the center on both sides with boards nailed to the nails. With a significant load and length of such insurance, there may be several. In this case, too, planks and nails are enough.

For large houses

With a significant distance between the two outer walls, a headstock and struts are installed. This design has high rigidity, since the loads are compensated.

With such a long span (up to 14 meters), it is difficult and expensive to make an integral tightening, therefore it is made of two beams. It is connected with a straight or oblique cut (figure below).

For a secure fit, the joint is reinforced with a bolted steel plate. Its dimensions should be larger than the dimensions of the cut - the extreme bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the cut.

In order for the circuit to work normally, it is necessary to make the braces correctly. They transmit and distribute part of the load from the rafter legs to the tightening and ensure the rigidity of the structure. Metal pads are used to strengthen the connections

When assembling a gable roof with hanging rafters, the cross-section of lumber is always larger than in systems with layered rafters: there are fewer load transfer points, therefore, each element has a large load.

With layered rafters

In gable roofs with layered rafters, their ends rest on the walls, and in the middle part they rest on load-bearing walls or columns. Some schemes burst the walls, some don't. In any case, the presence of a Mauerlat is required.

Non-thrust diagrams and cutting units

Houses made of logs or beams do not respond well to spacer loads. For them, they are critical: the wall can fall apart. For wooden houses, the rafter system of a gable roof must be non-thrustable. Let's talk about the types of such systems in more detail.

The simplest spreader-free diagram of the rafter system is shown in the photo below. In it, the rafter leg rests on the Mauerlat. In this version, it works for bending without bursting the wall.

Pay attention to the options for attaching the rafter legs to the Mauerlat. In the first, the support area is usually beveled, while its length is no more than the section of the beam. The depth of the cut is no more than 0.25 of its height.

The top of the rafter legs is laid on the ridge beam, without fastening it to the opposite rafter. The structure turns out to be two single-pitched roofs, which in the upper part adjoin (but do not connect) one to the other.

It is much easier to assemble the version with rafter legs fastened in the ridge part. They almost never give space to the walls.

For this scheme to work, the rafter legs at the bottom are attached using a movable joint. To secure the rafter leg to the Mauerlat, one nail is hammered from above or a flexible steel plate is placed from below. For the options for attaching the rafter legs to the ridge run, see the photo.

If the roofing material is planned to be used heavy, it is necessary to increase the bearing capacity. This is achieved by increasing the cross-section of the elements of the rafter system and strengthening the ridge assembly. It is shown in the photo below.

Reinforcement of the ridge knot for heavy roofing material or with significant snow loads

All of the above gable roof schemes are stable in the presence of uniform loads. But in practice, this practically does not happen. There are two ways to prevent the roof from sliding towards a higher load: by installing a scrum at a height of about 2 meters or with struts.

Variants of rafter systems with scrapes

Installation of scrapes increases the reliability of the structure. In order for it to work normally, in the places of its intersection with the drains, you need to fasten it to them with nails. The cross-section of the timber for the fight is used the same as for the rafters.

Attached to the rafter legs with bots or nails. Can be installed on one or two sides. See the figure below for attaching the scrum to the rafters and the ridge girder.

In order for the system to be rigid and not "crawl" even under emergency loads, it is sufficient in this version to provide a rigid fastening of the ridge bar. In the absence of the possibility of its horizontal displacement, the roof will withstand even significant loads.

Systems of layered rafters with struts

In these options, for greater rigidity, rafter legs are added, which are also called struts. They are installed at an angle of 45 ° to the horizon. Their installation allows you to increase the span length (up to 14 meters) or reduce the cross-section of the beams (rafters).

The brace is simply placed at the required angle to the beams and nailed from the sides and bottom. An important requirement: the brace must be cut accurately and fit tightly to the uprights and rafter leg, excluding the possibility of its deflection.

Systems with rafter legs. Above the spacer system, from the bottom - non-spacer. The nodes of the correct felling for each are located next to each other. Below - possible schemes for attaching the strut

But not all houses have the middle load-bearing wall in the middle. In this case, it is possible to install struts with a tilt angle of 45-53 ° relative to the horizon.

Strut systems are necessary if significant uneven shrinkage of the foundation or walls is possible. Walls can sit in different ways on wooden houses, and foundations on layered or heaving soils. In all these cases, consider the device of this type of rafter system.

System for houses with two internal load-bearing walls

If the house has two load-bearing walls, two truss beams are installed, which are located above each of the walls. Benches are laid on the intermediate bearing walls, the load from the rafter beams is transferred to the benches through the racks.

In these systems, the ridge run is not installed: it provides thrust forces. The rafters in the upper part are connected to one another (they are cut and docked without gaps), the joints are reinforced with steel or wooden lining, which are nailed.

In the upper non-thrust system, the tightening force is neutralized by the tightening. Please note that the tightening is placed under the purlin. Then it works efficiently (top diagram in the figure). Stability can be ensured by uprights, or by joists - beams installed obliquely. In the spacer system (in the picture it is below), the cross member is the crossbar. It is installed above the purlin.

There is a variant of the system with racks, but without the rafter beams. Then a stand is nailed to each rafter leg, which rests on the intermediate bearing wall with the second end.

Fastening the rack and tightening in the rafter system without a rafter girder

For fastening the racks, 150 mm nails and 12 mm bolts are used. Dimensions and distances in the figure are in millimeters.

The basis of any rafter system is the rafters, which are usually subdivided into the layered type, hanging rafters, as well as hanging trusses equipped with sleepers. Roof rafters are among the most reliable structural elements and have a characteristic difference in the form of intermediate support posts, which can be erected in the conditions of internal walls, arches or ceiling beams.

Differences between hanging and layered rafters

A rafter system is most often used in buildings that have additional rows of walls. Such walls are used as additional supports for the rafter system. At the same time, the parameters of the building can reach eighteen meters, subject to the presence of two additional supporting elements.

The main requirement is no more than eight meters of span between two supports. The rafter step depends on the characteristics of the calculations and can be 80-120 centimeters. The lower segments of the layered rafter system are supported in the form of special rafter beams, as well as a Mauerlat.

Support posts and purlins are separated by struts, which relieve the purlins and give the entire structure the required degree of rigidity. In addition, the struts serve as unloading elements for the legs of the rafter system and allow you to increase the parameters of the overlapped width of the room. Rafter legs that are longer than the standard dimensions of the lumber used can be of an integral design.

The difference between hanging and layered rafters

The hanging type of rafter system has characteristic differences from the layered type... Only the supporting walls act as a support for the lower ends of the rafters, and the rafter legs of this design have a load in both directions of the mounted rafter system.

In addition, the suspended structure has a significant degree of loads that expand the supporting walls. Such loads are leveled by means of special ties that unite the legs in a hanging rafter system. Wood or metal can be used as a material for puffs, and a horizontal at a convenient height is always selected for location. It should be borne in mind that the higher the puffs are located, the more durable the fastening to the rafter system should be.

Most often, the layered type of rafters is used to equip gable roofs over structures with a wall length of no more than six meters.

The structure of the rafter system

The main elements of the layered rafter system are the inclined type of beams, which must be placed along the roof slope. The element-by-element composition of the correct layered rafter system is as follows:

rafter legs, which are the element to which the lathing structure is mounted;

girders, which are elements of the rafter system, which fit not only on the main walls, but also on pillars of an intermediate nature;

racks, struts, benches, mauerlat, which are used to strengthen the entire structure and allow more evenly distributing the entire rafter load on the purlins and the supporting type of structures.

The need for application

A rafter roof structure is necessary in cases when it is required to bridge spans with a maximum length of six meters to six and a half meters, subject to the condition for the presence of additional supporting structures in the form of columns or walls capable of supporting the racks.

The most expedient design feature is the use of a sliding support for the rafter system, which allows the attachment of various intermediate rafters to the Mauerlat.

Fastening the rafters to the Mauerlat

Spans with maximum lengths in conditions of private housing construction are extremely rare. That is why, when erecting individual buildings, it is recommended to use the layered type of rafters.

The technology is based on the support of rafter legs on the Mauerlat, but in the case of wooden buildings, the upper wall row takes over the function of the Mauerlat. Such a joint is the most important in a layered rafter system. The use of the crossbar, which tightens the rafter legs, makes it possible to increase the span length to eight meters, in the conditions of one support - up to twelve meters, and when using two supports - up to sixteen meters.

Calculation of roof elements

Any configuration and structural features of the roofing system are decided at the stage of building design. Roof construction fundamentally affects the range of materials used in the installation process and the construction of the load-bearing walls. That is why the rafter structure, which will serve as a support for the roof, as well as the sheathing frame are the main subjects of roof calculations.

For a competent section of the rafter legs, the indicator of their length is taken as the basis.

If the span between the rafters is 100 centimeters:

length less than three meters - bars 8x10 cm or logs 10 cm;
length 3-3.6 meters - bars 8x13 cm or logs 13 cm;
length 3.6-4.3 meters - bars 8x16 cm or logs 16 cm;
length 4,3-5 meters - bars 8x18 cm or logs 18 cm;
length 5-5.8 meters - bars 8x20 cm or logs 20 cm;
length 5.8-6.3 meters - bars 10x20 cm. or logs 20 cm.

If the span between the rafters is 140 centimeters:

length less than three meters - bars 8x13 cm or logs 13 cm;
length 3-3.6 meters - bars 8x16 cm. or logs 16 cm;
length 3.6-4.3 meters - bars 8x18 cm or logs 18 cm;
length 4,3-5 meters - bars 8x20 cm or logs 20 cm;
length 5-5.8 meters - bars 10x20 cm or logs 22 cm;
length 5.8-6.3 meters - bars 12x22 cm. or logs 24 cm.

If the span between the rafters is 175 centimeters:

length less than three meters - bars 9x10 cm or logs 15 cm;
length 3-3.6 meters - bars 8x18 cm or logs 18 cm;
length 3.6-4.3 meters - 9x18 cm bars or 18 cm logs;
length 4,3-5 meters - bars 10x20 cm. or logs 20 cm.

If the span between the rafters is 213 centimeters:

length less than three meters - bars 9x16 cm or logs 16 cm;
length 3-3.6 meters - bars 9x18 cm or logs 18 cm;
length 3.6-4.3 meters - bars 10x20 cm. or logs 18 cm.

Features of mounting and fastening

The entire technological process for the rafter layered system consists of several main stages:

preparation of lumber according to the calculations;

if necessary, splicing the elements missing along the length using self-tapping screws or nails;

production of templates for rafters, racks and struts;

lifting the prepared lumber to the roof;

installation of racks and a ridge beam run provided by the roof structure and fastening the racks to supporting structures to prevent unwanted movements;

installation of rafters to fasteners and fixing them in the preferred way on the Mauerlat;

the upper rafter connections should be fixed to the ridge beam or to each other;

if horizontal contractions are designed, then it is necessary to fix them;

installation of supporting structures, including struts and trusses;

if the plumb lines can be affected by the structural features of the roof and rafter legs, then it becomes necessary to pre-install them;

in the case of the support of the rafter legs in the Mauerlat by means of a tooth or thorn, it is necessary to perform lengthening with fillets, which are sheathed around the entire perimeter with a solid type of crate.

Further, the completed rafter structure using layered rafters is sheathed with crate, on which a roofing cake with vapor barrier is mounted and, and then insulation and roofing are performed.

For more information on installing rafters, see the video.

The standard coefficient of shrinkage of a log house, the height of which is about three meters, is about five percent. Thus, the shrinkage of a house in one year can be about twenty centimeters, which negatively affects the load-bearing elements of the roof. When designing, competent builders make up two options - the initial one and taking into account the shrinkage.

Hanging rafter systems are devoid of such problems.... For the layered type of rafters, it will be necessary to apply one of several possible options:

wait for the final shrinkage of the structure;

apply a rafter system with sliding supports;

to perform the strengthening of all supporting structures with expansion joints, which are allowed to use screw jacks.

Summing up

When installing wooden rafters on stone supports, proper insulation should be performed using two layers of roofing material or any other waterproofing material.

When using layered rafters for arranging roofs of an attic type, it is necessary to install an internal timber frame under the lower rafters, and rest the upper rafter legs against the ridge girder mounted on the racks.

To make the connection of the rafter leg with the Mauerlat, it is recommended to use a slider or hard pinching.

For the layered type of rafters, a butt joint is allowed, which is performed by means of metal plates. For such a connection, it is required to leave a significant end angle, which, in the process of converging, allows the rafters to emphasize each other.

The overhead rafter system can be made with an overlay connection, which means drilling special holes for the fastening bolts.

In order for the constructed building to serve for more than one year, it needs both a solid foundation and a strong roofing system that can withstand the vicissitudes of the weather. The roof should withstand heavy loads with dignity: heavy snowfalls, sudden gusts of wind, heavy rainfall. The roof rafter system is best suited for this.

Roof trusses and its types

The rafter system is the basis of the roof, which focuses on the supporting elements of the structure and also serves as a frame for various types of materials for the roof: insulation, waterproofing, various coatings.

The dimensions and design of the rafters depend on:

purchased material;
the size of the building;
dimensions of the house;
building material for rafters;
individual customer preferences;
roof loads relevant for a certain region.

The rafter system has:

crate - beams that fit in the perpendicular direction on the rafter legs;
screeds that absorb tensile forces;
upright wooden racks;
mauerlat - a bar, the installation of which is carried out along the wall, the rafters are placed on it;
rafter legs are a kind of wood beams that take on the main load of the roof.

Each of the above factors is very important, since it is necessary to understand which type of rafter system will be optimal for a particular situation.

When it comes to low-rise buildings, wood structures are the most common. In many cases, three types of truss trusses are used: hanging rafters, layered rafters and a mixed rafter system.

Characteristics of hanging rafters

Hanging rafters are the most elementary type of rafter systems, their characteristics:

If the roof of the house is of a complex structure, the types of rafters can be alternated. For example, if there are supports or an average main wall, layered rafters are installed, and in the absence of such elements, hanging rafters.

Features of layered rafters

For a layered rafter system, the house must be additionally equipped with a load-bearing wall located in the middle. Distinguish layered rafters on the following grounds:

The design of the combined system is the most complex, since it includes parts of two other types of rafters - hanging and layered. It is used for the attic roof. The walls of the rooms, which are located on the second floor, are formed by vertical supports, these supports are also intermediate posts for rafter beams.

The part of the rafters that connect one end of the racks functions as a crossbar for the ramps located on the side, and for the upper part of the structure they are tightening.

At the same time, the horizontal bars perform the following functions: for the upper slopes - the Mauerlat, for the side ones - the ridge bar. To increase the strength of the roof, struts are mounted that connect the side slopes and vertical posts.

The combined sling system to manufacture is the most complex and time consuming, but these disadvantages are fully compensated by the increase in the load-bearing qualities of the roof in the absence of unnecessary supports, especially when there is a need to bridge significant spans in the building.

You can increase the bearing qualities of the roof using a mixed rafter system

Roof trusses for various roof types

During the construction of a certain building, rafter systems of one type or another are necessarily used, and the type of roof will completely depend on the project of the future structure.

Roof truss for gable roof

A gable roof is a common roof construction for residential buildings that have no more than three stories. Preference is given to just such a design due to the technical characteristics of the inclined shape of the rafter system, and also due to the fact that the installation work is carried out easily and simply.

The gable roof truss system includes two rectangular inclined planes. The upper part of the building looks like a triangle from the front side. The main components of the gable roof are the Mauerlat and the rafter legs. In order to properly distribute the load along the rafters and walls, struts, crossbars and racks are mounted, thanks to which you can create a durable, rigid, elementary and easy installation scheme for a structure for a gable roof.

A gable roof is considered the simplest roof system; it is used for residential buildings of no more than three floors.

On top of the rafters, you can mount a sparse or solid lathing, and then attach a bituminous coating, tiles or some other type of material to it. The rafters and the sheathing itself are usually made of beams or planks, which are fastened with nails, bolts or metal fasteners. Metal profiles can be used as rafters, thereby overlapping significant spans. In this case, you do not need to use extra racks and struts.

The device of the rafter system for a gable roof allows you to evenly distribute all the existing load along the perimeter of the building. The lower ends of the system focus on the Mauerlat. They are fixed with fasteners or metal brackets. By the angle of inclination of the rafters, you can determine at what angle the roof slopes will be inclined.

The rafter system for a gable roof allows you to evenly distribute the load from the roof along the perimeter of the building

Rafter system for hip roof

When arranging a system for a hip roof, you will need to install different types of rafters:

wives (shortened);
lateral;
hip main;
oblique (diagonal elements that form a ramp in the shape of a triangle).

The rafter legs located on the side are made from planks, and they are mounted identically to the details of a traditional pitched roof with a layered or suspended structure. Hip main rafters are layered parts. Planks or bars are used for the handicraftsmen, which are attached not only to the Mauerlat, but also to the diagonal beams.

To install this type of structure, the angle of inclination is accurately calculated, as well as the section of the support beams. The dimensions of the parts also depend on the length of the span.

To prevent the hip roof from deforming under heavy load, the angle of inclination of the diagonal beams for the rafters should be accurately calculated

Observe symmetry when installing diagonal rafter beams, otherwise the roof will deform from a significant load.

Sloping roof rafter system

A sloping roof is a structure with rafters, which consist of several separate elements. Moreover, they should be located at different angles relative to the horizon. And since the lower rafter part is almost vertical, the attic room of the building receives additional space, so that it can be used as a living room. The device of this type of roof is performed during the construction of a four- or gable structure of rafters.

Professionals need to calculate a four-slope rafter system, but a gable broken roof can be made independently, since its installation is very simple. For this, it is necessary to install a support frame, which should consist of purlins, as well as racks. The horizontal parts are fixed with hanging rafters. But the supports of the broken roof are fixed to the Mauerlat with the shortened legs of the rafters.

The assembly of rafters for a broken gable roof can also be performed by non-professionals, since the installation of such a roof is very simple

"Cuckoo" in the truss farm

The so-called cuckoo on the roof is a small ledge that is located on the attic floor. A window is located here for better illumination of the attic room. Installation of "cuckoo" is carried out carefully, while controlling the parameters of the entire structure: the depth of the cut, the angle of inclination and other factors. However, before that, the necessary measurements are made.

The first stage of work begins with the installation of the Mauerlat (a beam with a section of 10x10 cm, which is needed to support the lines). The rafter system acts as a skeleton for the roofing material. To give the structure rigidity, spacers are used, which are mounted between the two legs of the rafters.

After the installation of the truss is completed, the crate is laid, the type of which depends on the purchased roof covering. The installation of the lathing is done in continuous or with a certain step. For it, boards, OSB and plywood sheets are usually used. In addition, the installation of the roofing material must be identical throughout the roof.

The main difficulty in installing such a rafter system is the location of the inner corners. Snow can accumulate in these places, which means that the load will increase, which is why a continuous crate is made.

A "cuckoo" on the roof is a small ledge on the attic floor, under which there is an additional window

Chalet roof truss roof truss

A feature of the device of this design is the removal of visors, as well as overhangs outside the house. In addition, there should be roof rafters and beams extending up to three meters along the sides of the building. Each of these elements is fixed with a bracket to the building wall at the bottom. Next, the edges of the beams are tied. They serve as a support for covering the roof of the building.

But creating large overhangs, it is necessary to install the reinforced belt in parallel with the installation of the Mauerlat studs. It is necessary to make anchors to help secure the consoles. In this case, the rafters are perfectly fixed with anchors and, moreover, with tie-ins.

To take out the side cornices, a ridge bar is made, after which beams are brought out at the level of the Mauerlat, which should be identical to the length of the ridge. The truss is based on these details of the structure, and in the future - the building material for the roof.

When designing a building, the angle of the roof-chalet is calculated based on the characteristics of the local climate and other factors. With a slope angle of about 45 °, the load from the snow is not taken into account, since with this option it will not linger on the roof. At the same time, the sloping roof will withstand the load from the snow, but it is necessary to install a reinforced truss truss. Before installing the roof-chalet, a building project is being prepared, because the originality of the roof itself, as well as the long cornices and its overhangs, oblige this.

Chalet-style roofs are characterized by canopies extended several meters outside the house.

Roof truss for soft roofs

A soft roof is made in various ways, however, there are general characteristics in the technological methods of its construction. Initially, you need to prepare. When equipping a roof for a house made of foam concrete or other material, a Mauerlat is first installed, then a cut is made in the upper crowns of the building under the ceiling beams in steps of up to one meter. The distance between the boards is calculated based on the type of rafter structure.

Separate parts of the rafter system are mounted. To completely eliminate the risk, the boards of the rafter legs on the ground are attached with screws. After creating a truss, it is lifted to the top of the building.
All the elements of the rafters are fixed with ceiling overlap, internal boards, jibs, and also crossbars. Further, this base for the roof will become a single whole structure.
The next stage is the lathing, which is installed under the soft roof with little or no gaps. Gaps of no more than 1 cm are allowed. Quite often, leveling plywood is installed on top of the boards. Its sheets are laid using the brickwork method. The resulting joints are not aligned with the gaps between the plywood and the board.

If the length of the crate boards is not enough, then the joints of the parts must be located in different places. In this way, you can correctly distribute the areas that have been weakened.

Independent manufacture of the rafter system

Before the installation of the rafter system begins, the Mauerlat must be fixed to the longitudinal walls with anchors. Next, you need to decide on the desired section of the legs for the rafters, depending on the distance and their length. If there is a need to increase the length of the rafters, then connect them with various fasteners.

When using different insulation, you need to choose the ideal distance between the rafter elements in order to reduce the amount of insulation scraps.

Installation of the rafter system must be done in the following order:

A template is made according to which the farm is assembled. 2 boards are taken, corresponding to the length of the rafters, and connected to each other from one edge only with a nail.

A rafter template called "scissors" will help you quickly assemble the entire roof truss system
The result is a structure called "scissors". Its free edges are placed on supports at the points of contact of the rafter legs. As a result, the final angle should be obtained, that is, the angle at which the roof slope will be inclined. It is fixed with several long nails and transverse planks.
A second template is made, thanks to which the cuts are installed on the rafters. It is made of plywood.
On the rafters, special assembly cuts are cut out (a prepared template is used for this purpose) and they are connected at an angle of inclination of the slope. You should get a triangle going up the stairs to the roof. Next, it must be attached to the Mauerlat.
Initially, two side gable rafters are mounted. Their correct installation in the vertical and horizontal plane is due to temporary struts attached to the rafters.

For the correct installation of the entire rafter system, the first pair of rafters is installed on the roof
A cord is pulled between these tops of the rafters. It will indicate the future ridge and the level of other rafters located in the gap.
Raise and mount the remaining rafters at the initially calculated distance, which should be at least 60 cm from each other.
If a bulky rafter structure is provided, then it is additionally reinforced with struts, supports, and so on.

The bulky structure of the rafters is additionally reinforced with struts and supports
A ridge bar is installed on special supports, to which not only short, but also diagonal and intermediate rafter elements are attached.

Correct fastening of the ridge bar ensures the reliability of the entire rafter system

Typical nodes of a standard rafter system

The strength of the rafter structure depends on the perfectly matched section of the boards, as well as on the high quality of the rafter assemblies. The connection of parts for the roof structure is done according to the established rules.

The main typical nodes in the rafter system:

support node of the rafters on the Mauerlat;
ridge;
unit for combining the upper puffs and the entire rafter system;
fastening the brace, rack, as well as rafters and beams.

After the design of the rafter system has been chosen, it is necessary to draw up a plan in which all the nodes are selected. In each structure, they are made in different ways, since it depends on different nuances: the type of roof, its size, the angle of inclination.

Rafters from a profile pipe are a metal structure that is assembled using lattice rods. The very production of such farms is a very time consuming process, but also more economical. For the manufacture of rafters, paired material is used, and kerchiefs are connecting elements. The structure of the rafters from shaped pipes is assembled on the ground, while riveting or welding is used.

Thanks to such systems, any spans are overlapped, but the correct calculation must be made. Provided that all the welding work will be done with high quality, in the future it remains only to transfer the structural elements to the top of the building and assemble them. Bearing rafters from a profile pipe have many advantages, such as:

Crossbar in the rafter system

The crossbar is a fairly broad concept, but in the case of roofs, it has a certain meaning. The crossbar is a horizontal beam that connects the rafters. This element prevents the roof from expanding. It is made of wood, reinforced concrete, and also metal - it all depends on the type of structure. And the crossbar serves to distribute the load that the rafter system has.

It can be fixed in various places between the legs of the sling. There is a direct pattern here - if the crossbar is fixed higher, then the timber for its installation must be selected with a large section.

There are many ways to fix the crossbar to the rafter system:

bolts;
nuts;
studs with washers;
special fasteners;
nails;
mixed fasteners, when different types of fasteners are used in parallel.

The mount exists with a cut-in or overhead. In general, the crossbar is a design unit, as well as the entire roof slings system.

The crossbar in the rafter system is designed to strengthen the roof structure

Fastening the rafter system

To ensure the reliability of the rafter system, it is necessary to first figure out how they are fastened to the supporting roof and ridge. If fastening is made to prevent deformation of the roof during shrinkage of the house, then on top of the rafters are fixed with a hinge plate or nut and bolt, and below with a sliding support.

Hanging rafters need a tighter and more reliable fastening in the ridge, so in this case you can apply:

overhead metal or wooden plates;
cutting method;
connection with long nails.

In the layered system, the rafter legs are not interconnected, since they are attached to the ridge run.

The rafters are fastened to the Mauerlat by the cutting method, which is done in the rafter leg. Thanks to this method of fastening, the roof support will not weaken. Cutting is also done when installing the rafters on the floor joists. In this case, the cut is made in the support beam.

Video: how to make rafters with your own hands

Thus, a perfectly matched rafter system and their design characteristics will help create the foundation for a reliable roof for your home.