How to properly install the truss system. The preparatory stage for the installation of rafters

is not an easy task. This statement is obvious and understandable both for a professional builder and for a person who is only superficially familiar with the issue. There are no trifles in this matter, and each of the stages of construction requires careful study and years of experience practical application acquired knowledge. And although, thanks to the development of technologies, the production of many materials and the improvement of tools, the work is greatly facilitated, some stages are a task that can only be carried out by a person who really understands the essence of the material.

It is especially important to figure out how to install the rafters on the roof. It is immediately necessary to make a reservation that if there is no proper experience in carrying out such work, then it does not make sense to take on them. But on the other hand, any experience is a matter of time, and the essence lies in knowledge, so it will not be superfluous to study the issue at least in theory.

First you need to say a few words about what a rafter is. So it is customary to call the main element of the roofing system, which is a long beams located vertically and at an angle relative to the walls. It is the rafters that are the original basis of the entire roof. Its main elements are mounted on top of the rafters, which means that mistakes made at the stage of installation of the truss system will lead to a violation of the installation technology and the rest of the roof. talking plain language, improper installation of rafters is the current roof. That is why the question of how to properly mount the truss system is of paramount importance when it comes to the roof of the house.

Types of rafters

Speaking about the installation of the truss system, it should be noted that there are two main technologies for completing the task.

1. Overhead rafters.
2. Hanging rafters.

These technologies are very different from each other, so it is quite true to consider each option separately and in more detail.

Rafters

Roof rafters are roof elements that, when installed, in addition to the fulcrum on the Mauerlat and among themselves, provide for the installation of special racks, which will also be supported. As a result, it turns out that the resulting spacer stresses and subsequent mechanical loads exerted by the remaining elements of the roof are evenly distributed and mutually compensated.

As for how exactly to install layered rafters on a house, it is useful to know here that there are several installation methods. The main differences relate to the methods of fixing the rafters to the Mauerlat and connecting the rafter legs to each other.

• First, the bars used as rafter legs must be prepared. The point is that in the place of their contact with each other, it is necessary to choose half the thickness of the beam so that when the rafters are connected to each other, they are strictly in the same plane, without displacement.
• In addition, at the junction of the rafter leg and the Mauerlat, special cuts can be made on the rafters, which will help ensure that the supports do not move apart.
• At the top, the rafters, in addition to fixing with each other, are attached to an additional support - a longitudinal beam, which is laid across the direction of the rafters. Thus, the rafters are firmly fixed already.
• Further, the rafter legs can be additionally pulled together at the top or bottom, and possibly in both places, if the situation so requires.

If we talk directly about the methods of fastening the rafters, then there are also many options. For this purpose, building brackets can be used (convenient for fixing rafters to the Mauerlat), and various auxiliary struts and ties, as well as steel mounting plates and the like. Self-tapping screws, studs, wooden wedges, the staples mentioned above, and in general everything that the situation and experience in carrying out such work will allow, can be used as consumable fasteners.

hanging rafters

Another option for manufacturing a truss system is home installation. hanging rafters. By and large, the process of installing supports using this technology may resemble the one described above, but this is not entirely true, for a number of reasons, one of which is that for the installation of hanging rafters it is not necessary to install a central support like a longitudinal beam, as is necessary in the case described above. The rafters are connected to each other and to the Mauerlat, so it turns out that they seem to be hanging on the frame of the house. This somewhat simplifies the work with technical side and allows you to mount truss system on houses that do not have a central load-bearing wall.

As for how to install hanging type rafters, this happens in in general terms in the following way:

• First, the bars are connected to each other. At this stage, it is necessary to ensure that the joints are even and strong.
• Then I set the formed rafter legs on top of the log house and fix it.

It is important to understand that this process may seem simple only in words, since it entails not only the application of physical effort, but also the use of a sufficiently large amount of knowledge and skills, which not everyone can boast of.

The fastening of the rafter legs to each other can be carried out, as in the first variant, in several ways. For example, you can pull the rafters together with a horizontal bar at the bottom, just above the Mauerlat level, or vice versa, equip an additional screed at the top, closer to the convergence of the rafters. And you can combine options, which will only add strength to the structure. But here it is important to remember that any excesses are not good for the cause.

How large quantity additional elements will have a truss system, the more weight the entire roof will have, which means that the load will be greater, both on the walls and on the foundation.

Another way to further strengthen the hanging rafters is to equip them with a special supporting support, called the "headstock". First, the rafter legs are pulled together by a beam below, and then, using this beam as a support element, a vertical support is installed. In addition to the "headstock" you can use angular spacers, but it is important to remember that for the reasons described just above, excessive enthusiasm for the supports is inappropriate.

Concluding the above, we can add that it is, in principle, possible to put the rafters with your own hands. However, for this it is necessary to have both knowledge and experience, and if they are not, then better job entrust to professionals, and to acquire knowledge, you can limit yourself to the “position” of an assistant. Among other things, as a source additional information on topics of interest, you can use the appropriate videos that will help you understand the essence of the issue and clearly demonstrate the upcoming process.

Video

Watch Larry Hohn's informative film on how to build a roof:

The rafter system is the supporting load-bearing frame for the roof. That is why it must be reliable, since the durability of the entire structure directly depends on the quality of the material from which the elements of the system are made, and the professionalism of its assembly.

it is quite possible to manufacture and install, having a master nearby who has already done this more than once. Without experience in this work and a reliable adviser, it is dangerous to take it yourself - it is better to entrust this event to a team of qualified craftsmen. However, if you nevertheless decide to try your hand, then you need to approach all the details of the system with all responsibility and caution, since the work is not only difficult, but also quite dangerous.

In order for the entire roof system of the house to last a long time, dried wood is selected for the manufacture of its elements. conifers. For rafters, a beam is needed, having a size of 100 ÷ 150 × 50 ÷ 60 mm.

Coniferous wood is light in weight, which is favorable for the entire construction of the house, since a heavy rafter system, creating a lot of pressure on the walls, can lead to damage and destruction.

Another advantage of coniferous material for the construction of the foundation for the roof is a high percentage of cm of leafiness in its structure, which means an increased ability to withstand atmospheric moisture.

For the manufacture of elements of the truss system, it must meet certain requirements that directly affect the durability of the entire structure:

• Wood for mounting the rafter system must be aged, which will eliminate the risk of its deformation in the structure.
• The moisture content of wood should be no more than 2-2.5%.
• If a hanging rafter system is arranged, then for the puffs and the rafters themselves, wood of only the first grade must be taken.
• When building a layered system, the second grade of material is also suitable.
• For retaining elements - racks and struts, you can also use the third grade of wood, however, while trying to choose raw materials, on which the minimum number of knots.
• The exact thickness of the blanks is selected depending on the weight of the selected roofing material and on weather conditions in this region. This is especially true for the maximum thickness of the snow cover in winter period. For example, for middle lane Russian regions, it is necessary to calculate the load on 1 sq..m . roofs in 180÷200 kg.
• In addition, the parameters of the rafter legs depend on overall dimensions truss system and its slope.
• Before installing the system, the wood must be subjected to anti-fungal and fire-fighting treatment.

When installing a structure, you need to know and types of loads that the entire roof system is exposed - they are also taken into account when choosing the parameters of the rafters and installing the structure.

• Live loads are the weight of a person at repair work ah roofs, snow cover in winter and the force of gusts of wind.
is the weight of roofing, insulation and insulating materials.
• Seismic effects are special types of loads if the structure is located in seismically hazardous regions.

General design of the truss system

The most common the truss system has the shape of a triangle and is intended for arrangement. It includes several triangular elements, consisting of two rafter legs and auxiliary supports, and couplers. Each such triangular structure is called a rafter. The triangular elements of the system are located at a certain distance from each other, and most often it is from 50 to 80 cm.

This form has become traditional, as it creates better rigidity and reliability of the structure. It can end at the level of the walls or be continued for the installation of overhangs, which can be 40 centimeters or more long. Sometimes the rafters ending on the walls are built up with additional bars - “fillies”.

So, as mentioned above, the rafters are one triangular section, which includes:

• Two rafter legs connected on a ridge beam, or without its use, directly to one another.
• Braces or rafter legs are struts that support the rafter leg and lighten the load that falls on it. They rest against the bed and are fixed to it.
• Racks or vertical supports, consisting of bars. They, like the spacers, support the rafter leg, but closer to the center of the triangle. The rack is installed on the bed.
• A crossbar is a board that holds two rafter legs together.
• The fight is two crossbars fixed on both sides of the rafter leg. It performs the same task as the crossbar - it gives structural rigidity.
• Grandma is vertical beam ok, which is retaining and is installed in the middle of the triangle, resting against the floor beam and supporting the ridge. This part is used in hanging rafter systems.
• Run - they connect individual rafters in common system. They are parallel to the wall.
• Puffs are floor beams that connect the rafter legs, closing the rafter triangle.
• - a powerful bar installed at the upper end of the wall structure, to which elements of the truss system are subsequently attached.

There are three types of truss systems - these are layered, hanging and combined, i.e. including elements of both one and the other.

Hanging system

The hanging rafter system is used to cover buildings without internal main walls. The rafter legs are laid on the Mauerlat, fixed on the load-bearing walls.

Since a large one falls on such a system, which is transferred to load-bearing walls, the following additional elements are used to relieve this stress:

• A puff that simultaneously performs the role of a floor beam. It can be used with a span of up to 6 meters. If the span is larger, then it is raised higher along the rafter leg, and in the lower part the triangle is also closed with a floor beam.
• Headstock supporting the ridge, it is mandatory to install if the span between the bearing walls is more than eight meters.
• Struts extending from the headstock at an angle and supporting the rafter legs.
• Support that strengthens the rafter leg.
• A ridge beam is required in this system.

All elements are attached to each other metal corners, staples or twisted with screws.

Layered system

The layered system is more stable and reliable, thanks to additional supports in the form of capital partitions inside the building. Their presence makes it possible to attic extra room.

When making such a decision, the racks in the truss system are installed closer to the load-bearing walls, freeing up space.

In this system, the rafter legs are installed on the Mauerlat, which is fixed to the side load-bearing walls. For the reliability of the installation, rafter legs special grooves are cut out, and the elements are fastened together with brackets.

A ridge beam in this system is desirable if a large span is formed between the load-bearing walls, and it is planned to arrange a living space in the attic. The same applies to puffs, which in this case are fixed at the level of the ceiling of the future room.

You also need to know that the mauerlat must be very securely fixed to the wall with pins that extend 350 ÷ 400 mm deep into the wall, since it receives a large weight and dynamic load from the entire rafter system.

If it is assumed that the main walls of the building can shrink slightly, then the lower parts of the rafters are attached to the Mauerlat sliding fasteners, enabling the element to take the desired position without harming either the walls or the entire truss system.

Video: gable roof truss system

Installation of the truss structure

Having prepared suitable material and having a roof design project, you can proceed with its installation.

Gable roof

Mauerlat bars are fixed on the load-bearing walls on a pre-laid waterproofing material - ruberoid, and they mark the installation of rafters. It is very important to make the markings on both sides of the installation in the same way, otherwise the rafters will be skewed.

• The first rafters are adjusted and rigidly fastened directly at a height so as not to make mistakes in fastenings and in samples for installation on.
• Then, they are lowered down, and all the other rafters are made according to the first sample. On the ground, it is much easier and safer to fit all structural elements to each other and make reliable fastenings.
• When sawing the bars under the rafters, it is necessary to leave a small margin, i.e. make them a little longer than required so that you can fit them in place.
• To make it easier to navigate, exposing the first rafters, they take a beam, the length of which is equal to the distance between the outer edges of the walls - this will be the base or hypotenuse of the future triangle.
• The middle of the bar is determined, and a perpendicular board is temporarily nailed to it, having a height from the front wall of the structure to skate - peaks equilateral triangle.
• Then, laid out and fixed sides - legs triangles, they are rafter legs.

• If a hanging rafter system is selected, then the puffs are immediately marked and fixed.
• If it is planned to install additional fasteners, then they are fixed already in place, after installing the rafters on the roof.
• Further, the first rafters are first raised and temporarily installed. On each of them, places are marked where rectangular selections will be made to fix them on the Mauerlat.
• Then, the rafters are lowered down again, and grooves are cut out on them, having a right angle.

• For the first pair, taking it as a sample, the same grooves are measured and cut out on the remaining rafters.
• Further, two triangles rise to the walls, which are installed at the beginning and end of the future one. If provided ridge beam, then both installed parts are immediately connected to them.

Video: how the rafters are attached to the Mauerlat

• Cords are stretched along each slope between the already mounted rafters, which will also serve as guidelines for aligning the rest of the structure.
• First installed rafters are immediately reinforced by racks, struts and other elements of the system that give rigidity and reliability to the structure.
• Further, the remaining rafter pairs are raised and installed.
• If necessary, they are interconnected by runs and beds.
• When installing the rafter system, all its elements are temporarily fixed, since it is possible that some of them will have to be adjusted and reinstalled later. They are thoroughly fixed only after reconciliation of the entire system. Then corners, brackets, and, if necessary, sliding elements are used for fastenings. AT different places connections, self-tapping screws, nails, bolts, staples and studs are used.

If necessary, the rafters can be extended with "fillies"

• After the system is basically installed, the rafters can “filly” on overhangs - this is done so that the walls of the building are as well as possible covered from moisture getting on them during rain.
• The next stage of work is the device of the crate on top of the rafters. The thickness and width of the boards for this part of the structure are selected taking into account the installation technology of the selected roofing material - this will depend on the width, weight and length of its sheets.

Video: installation of a gable roof truss system

Single slope systems

It is generally accepted that a shed system is used only when constructing the roof of garages, sheds, gazebos and other non-residential buildings, but this is not at all the case. Such a roof also serves perfectly to cover residential buildings, and under it you can even arrange an additional warm room if you correctly calculate the slope of the structure.

A single-slope system can be considered as half gable roof, but with some deviations. For example, if when installing a gable roof, the gable part is the width of the building, then with a shed roof, its length.

The pediment can be raised from brick or wooden beams and boards. Its height will depend on the selected roof slope. The gable of the roof is raised high if an additional room is arranged under it.

The rafters in this system are easier to lay, but if the distance between the walls is large enough, then it is still necessary to install additional supporting elements for rigidity.

To correctly identify desired angle slope, you need to rely on the following factors:

• The thickness of the snow cover in winter and the average amount of precipitation in other seasons.
• The weight roofing, which is planned to cover the truss system.
• Temporary loads, in the form of gusts of wind.

The angle of this type of roof can vary from 5 to 45, and sometimes there are buildings with an angle of even 60 degrees.

Installation of a single-slope version is carried out on site, i.e. at a height, since the pediment and back wall buildings.

If the slope of the roof in a one-story mansion is not too large, then the rafters can be extended forward from the front or back of the house. This is done in order to arrange a veranda or terrace under the roof.

Attic systems

The most difficult to perform - attic systems roofs

If it is immediately laid down in the project to make the attic of the house residential, then you can choose one of two roof structures. The choice will depend on the desired attic area and ceiling height. It can be a gable with a high ridge or a broken mansard roof.

Gable roof

To arrange under a gable roof additional room, the space must be free from various additional fasteners. Therefore, you will have to get by with a minimum number of them.

Mandatory in this design will be racks and puffs - they will also perform the functions of the crate, on which it will be attached finishing material walls and ceiling of the building.

But in this case, it is very important to use massive bars for the floor beams, which will calmly withstand the weight of the truss system with insulation and roofing material, plus the entire load given by the pieces of furniture that will be installed in the room. In addition, it is necessary to mount the bars of the floor beams at a small distance from each other, which should not exceed 50 ÷ 60 cm, but in order for the walls of the building to withstand the entire load without problems, they must be quite massive and strong.

Installation of the system takes place in the same sequence as a gable roof.

Attic "broken" design

The mansard roof structure of the house is more complex than the usual gable, but its advantage is that living space, which is obtained as a result of its installation, will be much larger, and the ceiling will be higher.

An approximate diagram of the attic "broken" system

This type of roof is called broken, as the system consists of two parts, in each of which the rafters are located at a different angle.

The side rafters can be positioned at an angle of 30 or 45 degrees from the vertical - this is the most common installation options.

The top is fixed at an angle that can vary from 5 to 30 degrees from the horizon.

AT attic construction both rafter systems can be used. lower rafters it is preferable to arrange according to a layered system, but if there are no capital partitions in the building, then a hanging one can also be used. In the latter case, beams attic floor, as well as rafters, should be installed at a distance of no more than 50-60 cm from each other. It should be noted that the walls must be well fortified, since the load on them will be quite serious, much more significant than with a gable roof.

• The beginning of the construction of the lower truss system begins with the installation of racks, fixed with strapping from above, and from below - by floor beams. The distance between the rack systems will be the width of the room, and their height determines the height of the room.

Start of installation - installation of two rows of racks

• This frame will determine the placement of the remaining elements of the system.
• Next, you need to find the middle of the distance between the rows of racks, and this will determine location in the upper part of the attic. In this place, a vertical bar is installed, the same height as the rack system.

• Then, side rafters are installed, they are fixed to the rack strapping and a beam overlap, thus, triangles are obtained in which the rack and beam overlaps form a right angle.
• When all the side elements are installed, proceed to the installation of floor beams, they are also attached to the strapping bar and the end side rafter. A diagram of this bundle is shown in the first figure in this section.
• Further, the floor beams are connected to each other by a horizontal rail, which is stuffed on top of them, in the middle of the structure.
• Ridge rafters are installed, which are supported by struts. They are attached to the rail connecting the floor beams.

• On the ridge, the rafter legs can be fixed to the ridge board or connected by a metal or wooden plate to each other
• Sometimes, for structural rigidity, a supporting headstock is installed between the ridge and the floor beam.

• The crate of the gable walls is made with openings for windows. If the entrance is from the street, then on one of the gables, in addition, an opening for the door is provided.

• Further, if necessary, the entire truss system is sheathed with sheathing or plywood, if roofing material is chosen. soft roof, for example, flexible tiles.

Video: an example of installing a truss attic system

To equip the truss system is not at all simply, and you cannot cope with this work alone - you will need at least two assistants. It is desirable that at least one of the invited masters has some experience in this field of construction.

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

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

The roof option is approved at the design stage.

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

You can read how to calculate the truss system.

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

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

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

Rafter structures are also classified into:

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

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

Rafter systems of layered and hanging type

Calculation of the load on the rafters

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

Important metrics to consider:

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

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

Scheme of truss systems

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

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

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

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

This calculation is not always final.

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

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

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

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

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

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

What is the truss system

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

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

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

What is the gable roof truss system

Installation of a rafter system with layered rafters

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

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

The main support of the rafter legs is the Mauerlat.

Mauerlat installation

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

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

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

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

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

Mauerlat installation

Sill

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

Installation of a gable roof truss system

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

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

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

Installation of rafters

ridge knot

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

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

ridge knot

Racks

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

Run

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

Filly installation

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

Installation of a rafter system with layered rafters

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

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

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

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

Racks in the hanging system are not provided.

Puffs

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

The device of the truss system

Installation of strut beams

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

Strut beams

rafters

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

ATTENTION!

During installation hanging system prerequisite installation is the accuracy of calculations and the strength of the rafters and tightening.

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

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

Rafter installation

hanging rafters

How to strengthen the rafters of a gable roof

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

Strengthening can be done with:

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

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

The construction of a truss system is a rather complicated and responsible business. However, it can be done independently if you follow certain rules.

This article will talk about the elements of the roof structure, as well as how to put the rafters on the roof.

Before placing the rafters on gable roof, you need to find out what elements the roof structure consists of. It consists of:

• Mauerlat. This is a beam rigidly fixed along the load-bearing walls of the building. For its manufacture, as a rule, a bar with a section of 15 by 15 centimeters is used. serves as the bottom, and also evenly distributes the load created by the roof structure on the walls of the building. Between bearing wall and Mauerlat beam should be located waterproofing material, for example, roofing material. If the roof frame is made of metal, channels or I-beams are used as Mauerlat.

• Rafter legs. are the main element roof frame. Their size is taken in accordance with the design calculations. The lower parts rest on the Mauerlat beam, and the upper parts on the ridge beam. For their manufacture, regardless of the type of structure being erected, it is recommended to use pine board section 150 by 50 mm or 200 by 50 millimeters.

• Run. It is a horizontally located beam that perpendicularly crosses the rafter legs along the entire length of the roof. There are three types of runs in the truss structure: side, ridge and Mauerlat.

• Sill. It is a horizontal bar that is mounted on an internal load-bearing wall. This element serves as a support for the racks and evenly distributes the load they create. Beds install complex truss systems. In other words, this roof element is optional and is applied where necessary.

• Puff. It is an element of a hanging rafter system. The puff forms a triangular truss with rafter legs. This element reduces the expansion force created by the hanging rafters on the walls of the building. The location of the tightening depends on the type of roof structure being erected.

• Rigel. This element, like the puff, connects the rafters. The crossbar makes the structure more durable and stable. For its manufacture, a bar with a section of 10 by 15 centimeters is usually used. On the crossbar, in contrast to the tightening, there is a compressive load, and not a tensile one.

• Racks. It is a bar installed vertically. It is used if the width of the building is large enough. This element strengthens the truss system from the inside. Runs supported by struts are installed on the racks.

• Struts. They are inclined beams supporting horizontal elements. Struts reinforce the structure of the truss and counteract the distortion and compression of the roof structure.

• Roof overhang. This is part of the rafter legs protruding beyond external walls buildings by about 40 centimeters. The overhang protects the outer walls of the building from rain and melt water rolling down from the roof.

• Filly. It is a piece of board. Used to lengthen the lower part of the rafter leg.

Tools and materials

The roof structure should be made of coniferous wood. The moisture content of the wood used should be less than two percent. Before use, the material must be treated with special protective equipment.

For the manufacture of hanging rafters and puffs, they are made from first grade wood. Rafter legs are made of wood of the first and second grade. It is possible to use a tree of the third grade only for the manufacture of struts and racks.

The strength of the roof structure depends on:

• Reliability of connections;

• The quality of the material used;

• Correctness of the performed calculations.

Before you put the rafters on the roof, you need to prepare the following tools and materials:

• Axe;

• A hammer;

• Level;

• fasteners;

• waterproofing material;

• boards;

• Pencil;

• Chainsaw;

• Electric drill;

• A set of drills for an electric drill;

• Nails or screws;

• Roulette;

• Cord.

For the manufacture of stops, a bar or edged board. Wood elements should be treated with bio-protective and fire-retardant materials.

Before installation, you must select the type ridge connection and a method of fixing rafters to beams or mauerlat.

Calculation of the pitch of the rafters

This issue must be given special attention, because the strength of the roofing system depends on their cross section.

When calculating the distance between the rafters, the permanent and temporary loads on the roof being erected should be taken into account. The following elements create a constant load:

• roofing material;

• rafter system;

• roofing pie (vapor barrier, insulation, waterproofing);

• elements of decoration of the attic or residential attic.

• the weight of a worker performing roof repairs or maintenance.

To perform calculations (section and step of the rafter legs), theoretical knowledge is required, as well as practical skills. You can determine the approximate parameters of the roof structure using the following table:

When choosing a rafter pitch, it is necessary to take into account the type thermal insulation material. It is important to remember that the span between adjacent rafters should be 10 - 15 millimeters less than the width of the cotton insulation.

Also, when choosing the distance between the rafters, it is necessary to take into account the recommendations for laying the selected roofing material.

Types of truss system

There are two types of rafters: hanging and layered. Each type will be considered separately.

hanging

Hanging truss systems are used in cases where there are no internal supports (columns, walls) in the house. This design is supported by external retaining walls.

In this case, the rafters work in compression and bending. exert a bursting force on the outer walls of the house. To reduce it, use a puff.

The puff is made of a wooden beam or metal. Its location depends on the design of the roof being built.

For example, when building a roof attic type the puff is located at the base. In this case, it performs the functions of a floor beam. The higher the puff is located, the greater the load on it.

A hanging truss structure is used if the distance between the supports is less than 6.5 meters. For the manufacture of these rafters, boards, logs, or timber are used. To connect elements to each other, use:

• steel profiles;

• cuts;

• bolts;

• nails;

• pins.

Rafters

Rafters of this type are used in buildings with capital inner wall. These elements are usually made of wood.

The internal elements (column, wall) serve as a support for the layered truss system. This is their main difference from the rafters of the layered type.

rafters of this type work only for bending. Layered roof structures compared to hanging ones, they are more cost-effective and lighter.

How to put rafters on the roof

Installation of gable roof rafters consists of the following steps:

1. Making a truss truss template. It is necessary to lift two boards on ceiling, and then connect them together from one edge with nails. Next, you need to install the free ends of the boards on support beam and fix the angle between the boards. To do this, you need to nail the transverse jumper. Then you need to lower the resulting template onto the support beam and mark the angle of trimming the rafter legs with a pencil. It should be noted that the strength and reliability of the entire roof structure will depend on the quality of the template made.
2. Lower the made template down and start making rafters. The template must be well fastened so that when it is lowered, the angle between the rafters is not disturbed. The first manufactured truss truss is lifted onto the building and installed on the base.
3. Mark the cut point on the Mauerlat and rafter legs and cut with a chainsaw. Next, you need to start assembling the next truss truss.
4. Install on the Mauerlat beam along the edges of the building the first two roof trusses. The rafters installed along the edge of the Mauerlat beam are fixed on both sides with the help of props. Then pull a cord between them to determine the level. Rafter trusses must be installed perpendicular to the base of the ceiling.
5. It is necessary to assemble the remaining roof trusses after the level is set and all fasteners are checked. The rafters will not move if two boards are hammered between them. Next, you need to fix the cross bars and supports.
6. Perform installation of a vapor barrier, heat-insulating and waterproofing layer. Roofing material is attached to the crate. Its step depends on the chosen material for the roof.

This video shows how to put the rafters on the roof:

As you know, the truss system is the main Basic structure roofs. It is she who "holds" the entire load of the roofing "pie", as well as all the loads from snow and wind. That is why its construction must be treated "responsibly". How to install such a system? How are roof trusses installed? What are the nuances to be considered here? This and other issues related to the truss system will be discussed in the article.

General concepts

Installing rafters is one of the milestones construction of any roof. Most often, this work is entrusted to professionals, as it is quite difficult. But, if you have some experience in construction and carpentry, then you can do it yourself. But before proceeding with the installation of rafters, you should familiarize yourself with the roof structure itself.

This system includes the following components:

1. Stingrays. Their number depends on the type of roof. The most common option is a double-sided one. It is this main part of the roof that is supported by the rafters that you will lay.
2. Along the perimeter of all walls, from above is made. This element can be omitted if the house is built of wooden beams. The lower end of the rafters is attached to the Mauerlat. This element is necessary so that the weight of the entire system is evenly distributed on the walls.
3. Skate. This is top part roofs. Here slopes and rafters converge. This element is present in any type of roof except single-sided version.
4. Endova. It may not be included in all designs. The valley is present in cases where the slopes, and, accordingly, the rafters, form an incoming angle.
5. Overhang or cornice. This element is designed to ensure that precipitation flowing from the roof does not damage the walls and foundation. The overhang can be a direct continuation of the rafters or be their separate component. The cornice can recede from the walls to any distance acceptable to you, but it should not be less than thirty centimeters.
6. Roof. This part will directly protect your building from external influences. The roof may look like a kind of "pie". If in a, then you will have to install thermal insulation and other layers. If there is no attic, then it is enough to lay the roofing material and waterproofing.

The rafter system is the "backbone" of the entire roof. It is she who will carry all the loads from the roofing "pie" and other components. Therefore, the technology for installing rafters must be strictly observed. Proper installation will guarantee a long service life of the entire structure.


Material for rafters

During the construction of the roof, it is important to responsibly approach each stage. Installing rafters is "serious". But, if these elements are of poor quality, then from correct installation little will matter. Rafters can quickly fail and then you cannot avoid serious repair work.

Before proceeding with the DIY installation, you should select the material for these basic elements of the entire roof system. What option can be used? Here, experts will offer the following:




You can install wood rafters with your own hands, using only a regular carpenter's kit. The most commonly used bars. In some cases, boards can also be used. The most important thing is that the material is of high quality. Do not use boards or bars that have been in use for a long time.


Training

Before putting the rafters, you should go through the preparatory stage. First of all, you should draw up a diagram. Without an exact drawing correct installation rafters is impossible. When drawing up a diagram, the following points should be considered:

1. What truss system will be used. There are two options - this is layered and. In each case, the installation of rafters is carried out according to its own rules. This must be taken into account.
2. Decide on the slope angle. Various parameters are taken into account here. First of all, natural conditions in your region. The smaller the angle of inclination, the more snow accumulates. At the same time, it decreases wind load. With a large angle of inclination, the opposite is true. Secondly, recommendations from the manufacturer of the roofing material should also be taken into account.
3. Loads. Before drawing up a diagram, you should decide what forces will act on the entire structure. Based on this, all parameters of the rafters themselves and the frequency of their installation are calculated. Both variable and permanent loads are taken into account. The first includes atmospheric influences - these are precipitation and wind. Permanent loads include the weight of all roof components, including installed equipment, read more: .
4. The parameters of the rafters themselves. Here you need to calculate their length and cross section. These values ​​will depend on design features the roof itself, and from the loads that it must withstand, read also:.

After drawing up the scheme, you should prepare everything necessary materials and tools. Special attention it is worth paying the rafters themselves and other components of the truss system. Wood is a tricky material. Therefore, the installation of rafters should begin with their processing with various impregnations.


In addition, you need to carefully inspect each board or beam that will be used. If signs of decay or a large number of knots, then it is better not to use such material for installing rafters. You also need to pay attention to the moisture content of the wood. This parameter should not exceed ten percent.

In addition to wood for rafters, you need to prepare other materials and tools. First of all, stock up on fasteners. Installation of rafters is carried out using mainly nails. But besides this, metal brackets, corners and other devices can be used.

If we are talking about tools, then a regular carpenter's set will do just fine. Do-it-yourself installation of rafters is carried out using a saw, an ax, a planer, a drill and other tools. In addition, you should prepare devices for marking.

Methods for connecting rafters

Wood is excellent for processing. That is why, of course, in addition to all other advantages, it is chosen when building a roof. Due to the ease of processing, there are many ways to connect wooden elements. Before you start installing the rafters, you should know how they can be attached to each other, built up and connected to other components of the system.

You can use the following options to perform these tasks:




There are other methods on how to put rafters on the Mauerlat. Each particular option has its pros and cons. But in addition to the Mauerlat, the rafters must also be fixed to each other. This is done at the top of the roof ridge.

There are also many ways here. Installation can be carried out using bolts, plates, hinges or using a groove.


We carry out installation

And how to install rafters on the roof? What are the nuances and subtleties here? First of all, you should remember about safety. Laying rafters on high altitude- it is dangerous. It is best to do before installation scaffolding. But such a thing is very expensive and rarely used. Therefore, the installation of rafters on the roof should be carried out with the means personal protection- these are mounting belts and so on.

In addition, doing everything with your own hands and alone is an almost impossible task. It will be impossible to lift and put the rafters alone. Wood weighs a lot. In addition, the structures themselves will be quite large. Therefore, you cannot do without an assistant.

The very technology of installing rafters on the roof is as follows: