How to set the roof rafters yourself. What influences the choice of sizes and methods of fastening rafters

During the construction of any building, the completion of the main work is the construction of such an element as the roof. Its importance is exceptional in general for the entire structure, because the basis is a special truss system. It is the rafters for the roof in the future that will have to withstand any load from external adverse factors.

In this article

Beginning of work

The construction of the roof of any building is carried out using wooden or metal rafters. It is a specially designed system of series-connected elements that provide the load-bearing capacity of the entire roof as a whole.

In preparation for the assembly of rafters for the roof, it is imperative to draw up a drawing indicating all dimensions. This will be needed when calculating the right amount building materials.

For wooden rafters it is worth using dried wood, which is not affected by fungus and rot. And also you can not use a tree in the presence of large cracks and splits on it.

Metal rafters for the roof should not have visible and hidden deformations. No areas of corrosion are allowed. And most importantly, in no case should roof rafters be installed without treatment with anti-corrosion compounds.

wooden rafters

Do-it-yourself wooden roof rafters do not present any particular problems even for people who do not have a special architectural education.

But we must remember that there are certain foundations from which you should not deviate. First of all - this existing species truss systems.

Dimensions of truss elements

For wooden rafters, the most common is the use of timber and boards.

For supporting elements, a beam section of 100 * 100 mm is taken. If a board is used, then the minimum is 100 * 50 mm. The size of the board is also allowed 200 * 50, but no more. If, in order to save money, it was decided to use logs, their minimum diameter should be from 100 mm. And at the same time they must be necessarily processed and cleaned.

Before putting the rafters on the roof, you can use a special Internet service for exact definition the required dimensions of all elements where you need to make the main parameters of the roof. Or you can make all the calculations manually, taking the data taking into account the snow and wind load in the required region of the country.

It must be remembered that minimum distance between the rafters should be from 60 to 100 cm. Otherwise, the roof may be unreliable and not withstand the subsequent operational load.

The sequence of installation of elements of a wooden truss system

To build a reliable roof with your own hands, you must follow a certain sequence of actions.

The fire-fighting composition increases the degree of fire resistance of wooden materials in the event of a fire in the event of an emergency.

Fastening truss elements

To fasten all elements of wooden rafters, self-tapping screws with a length of more than 70 mm should be used. They must be made of stainless steel or with anti-corrosion treatment. This helps to prevent the occurrence of spot rot, which can subsequently spread to all elements.

Special mounting plates, beam holders and beam connectors with mounting brackets must also be made of anti-corrosion materials.

To join each element, it is necessary to make geometric cuts. With their help, additional adhesion between structural elements will be provided.

To install metal rafters, you may need to use a special welding equipment, since, in addition to the bolted nut connection, some elements require precisely welding together.

What is the result?

Following such simple rules and conditions, it will be possible to independently build a truss system of almost any complexity and the required type, depending on the needs of the owner of the house.

It is worth remembering that in no case should you allow savings on the quality of building materials. And in case of doubts about the correctness of the actions performed and uncertainty about own forces You should definitely seek professional help.

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Installing rafters: 2 simple instructions for self-fulfillment

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

Installation of rafters on a brick house

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

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

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

Construction technology

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

Installation of rafters on a frame house

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

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

Assembly technology

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

Summing up

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

December 12, 2017

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The installation of rafters, as well as the creation of the entire roof, is a very important process. Taking into account that the base of the roof can be fixed to the wall using improvised means for lifting, subsequent work on its creation, which includes the installation of rafters, will be impossible without scaffolding, which also includes mobile structures. Scaffolding is used to lift materials to the desired height, in addition, they can be used as a working platform for a person and a place for laying building materials.

The device of the truss system.

Preparation of scaffolding and scaffolding

Do-it-yourself rafter installation can seem like a lot of work, but if you follow all the tips and follow them correctly, the process will be fun. If you are building a house, then you must use at least 3 scaffolds, in any case, their number should not be less than 2. For work, it is better to make mobile scaffolding, as they are very convenient. Installation of rafters should begin only after all safety issues have been resolved, in no case should this be neglected, since health is more important than construction speed.

Types of truss systems.

If there is no internal load-bearing wall in the house, that is, there is no additional support, and the construction legs rest only on the outer walls of the house, then hanging rafters should be used.

What is a rafter? Translated from the Old Russian language, this is a design to support two pitched roof. And the rafter legs are inclined, with the help of which the roof slope is formed. The rafter legs are usually connected by "grandmothers" or "fillies", which are made vertically. The puff is a horizontal beam, with its help the rafter legs are connected.

Varieties of rafter designs

Roof structures, as a rule, contain the following components:

Schemes of layered rafters and their application.

1. Rafter legs are used to form the slope.
2. To transfer part of the load - columns or internal supports.
3. Various inclined elements (braces, braces) that perform the same functions as the racks.
4. Elements that fasten rafter legs to each other. Usually floor beams are used for this.

Triangle - optimal shape roof truss. This design has the highest rigidity.

Despite the many possible roof shapes, two types of rafters are commonly used:

1. Layered truss system;
2. hanging rafters.

Figure 1. Installation of rafters.

The first case is used subject to the presence of internal load-bearing elements in the building structure. At the same time, the rafter legs have an emphasis not only on external walls, but also on internal columns or supports. Racks are used to transfer the load. Figure 1 shows the mounting schemes of the rafters.

The hanging structure has an emphasis only on the outer walls, and in the ridge the rafters rest on each other. Hanging rafters are used in the absence of intermediate supports, while the span width is less than 12 m. The design feature is high rate expansion load, to reduce it, special puffs are used. The legs of such a rafter system should be strengthened with struts, which will also reduce the pressure on the load-bearing walls.

Walls made of brick or stone require the installation of a Mauerlat. Mauerlat - wooden beam, which usually has a cross section of 150x150 mm and is fixed with special studs. These studs must be pre-embedded into the wall. A waterproofing layer must be laid under the Mauerlat.

Do-it-yourself installation of hanging rafters on the Mauerlat: step by step instructions

For work you will need the following tools:

Scheme and installation of hanging rafters.

• axe;
• a hammer;
• knife for precise fitting of parts;
• pencil;
• plumb;
• roulette;
• building level.

To install the rafters, it is necessary to take a beam, the length of which will be 6 m, and the section 50x200 mm. It should be noted that if the cross section is suddenly small, then after some time, such a structure may sag. Based on the case described above, the roof slope, namely its angle, should be 33 º. The next step in installing the rafters is that, using scaffolding, you need to raise 2 beams and connect them at the top.

Knots of layered rafters.

1. On the rafter legs, you need to “cut the heel” in the following way so that the rafter rests well on the Mauerlat.
2. With the next rafter, you need to do the same. It will be nice if the rafter legs are marked as “left” and “right”.
3. After completing these works, the rafter legs must be connected.
4. After that, at the place where the rafter legs are connected, it is necessary to perform a “stump” with the correct angle, so that the rafters at the top are not overlapped, and then fastened with nails. This method is unreliable, as the rafters rest against each other.
5. For correct execution"Hemp" should initially attach one rafter to another, then draw a line of their connection (you can use a pencil for this) and only then saw off.
6. To prepare building material on the ground, you need to measure and make several templates at once.
7. Having done all the operations, we begin the installation of the rafters, first on one gable, and then on the other. Using nails, we fasten the rafters to the Mauerlat.
8. The following pairs of rafter legs are prepared according to ready-made patterns on the ground;
9. Then you need to pull the thread along the ridge between the already finished pairs of rafters and proceed with the installation of all the remaining rafters.
10. The distance at which the rafters are installed is 70 cm. Of course, in fact, it can be within 68-73 cm from each other. This is considered optimal distance for the roof, as it is reliable, and such a distance between the rafters will be convenient in the future when you stretch the film.
11. For these purposes, it is necessary to initially mark the Mauerlat, and then install the rafters on it.
12. It is worth noting that the adjustment must always be carried out with the help of a thread that is pulled between the rafters, when necessary, it will be possible to adjust the height of the rafter legs on the spot. In some cases, you need to put small boards under your feet.
13. Adjustment in the lower part in width, which is between the two rafters, is made according to the indicated markings on the Mauerlat. As for the upper part, here the adjustment is carried out using a temporary board with the same markings. This means that after each pair of rafters is installed, a board is temporarily nailed to the top of the left and right rafters according to the markings already made in advance, which correspond to the markings applied to the Mauerlat.
14. In the described case, the hanging rafters will need to be connected with a horizontal bar, that is, with a puff, due to the large distance between the supporting walls. It is worth paying attention to the fact that initially the rafter pairs were connected by a horizontal board in the area of ​​\u200b\u200bthe ridge, thus forming a ridge knot.

Gable roof installation.

In the case under consideration, due to the large distance between the bearing walls, where the width of the house itself is about 11 m, the puff will not consist of one bar, but of several interconnected boards. Such a puff, made of several boards, will help solve several problems at once:

• the result is a tightening of the desired length:
• it is worth noting that the strength and reliability of tightening made of 3 boards with a total thickness of 60 mm is much higher than if it is one beam with a thickness of 60 mm.

Quality roof: summing up

For the required length, 4 and 6 m boards were cut, after which they were fastened with nails, twisted with nuts and studs with rafter legs.

Under constant control, you need to keep the distance that is between puffs. It should be the same as that between the rafter legs.

To do this, you need to use narrow boards, as in the case of adjusting the distance of the rafter pairs at the ridge, which are marked and correspond to the markings on the Mauerlat. Always keep your distance under control!

In addition to all this, the puff and the skate were connected by another 1st board. Given the fact that there is no retaining wall, the puff will simply bend, unable to support its own weight. In order to avoid such troubles, the tightening together with the ridge of the rafter pair are connected by a “headstock”. All of the above actions must be done with each rafter pair.

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 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, the upper corner of which is connected in the center of the roof;
• Multi-forceps. Consist of trapezoidal or other slopes different forms, interconnected.

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

Rafter structures are also classified into:

• Hanging. With this type of roof frame due to the lack of load-bearing walls in the room;
• Layered. 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 rafters. gable roof and mounting options.

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

This calculation is not always final.

Additionally, the load 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

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

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

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

What is the gable roof truss system

Installation of a rafter system with layered rafters

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

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

The main support of the rafter legs is the Mauerlat.

Mauerlat installation

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

Mauerlat - a beam that is laid on a support (bearing wall) and is the base of the truss 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 from the inside, the bed should be fixed with twists of wire or staples. Next, markup is made for installing the rafters.

Installation of a gable roof truss system

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

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

Rafter beams should be fixed either by installing them in prepared grooves and 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 inner wall.

Run

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

Filly installation

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

Installation of a rafter system with layered rafters

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

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

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

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

Racks in the hanging system are not provided.

Puffs

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

The device of the truss system

Installation of strut beams

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

Strut beams

rafters

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

ATTENTION!

When installing a hanging system 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 the bearing capacity of the rafters.

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

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

Calculation of the pitch of the rafters

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

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

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

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

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

Material preparation

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

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

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

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

Types of rafters and features of their installation

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

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

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

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

Installation of the upper ends of the rafters

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

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

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

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

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

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

Methods for installing rafters on walls

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

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

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

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

If the rafter leg rests on the Mauerlat without an overhang, then special boards - fillies - should be installed to create a roof overhang.

The installation of rafters when installing a broken mansard roof has its own characteristics. In this case, first of all, a rectangular frame of racks and girders is mounted. Then, hanging truss trusses with a crossbar strut are attached to the girders, mounted on racks. Next, each rack is connected by a short rafter to the Mauerlat.

Do-it-yourself installation of rafters: how to set it correctly and over what distance

Learn how to install rafters with your own hands. Choice correct distance and how to install the rafters along with the video.

Installation of rafters: the specifics of sawing and the rules for installing the truss system

The truss frame sets the geometric and operational parameters of the pitched roof. Due to violations in the installation technology, due to flaws in the manufacture of its elements, distortions of the system, traditional leaks, holes in the coating appear, threatening emergencies. In order to build a reliable and stable roof structure, you need to clearly know how the sawing and installation of rafters is performed, followed by fixation to the supporting elements.

Classification of rafter legs

Rafters, or rafter legs, are wooden or metal beams installed on the house box at a given angle. They determine the configuration of the roof structure, take on and steadfastly resist the sum of permanent and temporary loads acting on the upper enclosing system of the building.

The structural simplicity of the rafter legs is extremely deceptive. In fact, these are quite complex elements that require careful marking and accurate cutting. Inconsistencies in the connections of the rafter legs with the Mauerlat, with each other and other components of the system lead to a change in the shape of the slopes, a violation of the integrity of the coating and the destruction of nodes.

On the other side, competent installation rafter legs can correct some errors in the construction of the box at home, and not aggravate the situation by a clear repetition and intensification of wall height differences. True, in such situations, the frame elements are made individually and scrupulously adjusted in fact directly at the facility.

However, before dealing with the specifics of installation, you need to find out what their design differences are, according to which the rafter legs are divided into two groups, these are:

• Hanging. Type of rafters that do not have an upper support. At the top of the roof, the rafter legs rest against each other with their ends. So that under the weight of the components of the roofing cake and snow, such a design does not burst the Mauerlat beam, the hanging rafters are connected with a horizontally installed puff.
• Layered. A kind of rafter legs, stacked on two supports of different heights. At the top, they most often rely on a ridge run installed in the cross to the rafters, less often they rest against each other, cut down at an angle. The bottom rests on the Mauerlat beam or rests against it.

The scope of their application and installation technology depend on which group the rafter legs belong to. The hanging variety is collected on the ground, and the trusses, made in the form of peculiar triangles, are raised to the roof and mounted in a form completely prepared for installation.

The advantage of building a truss frame using hanging technology lies in the safety of work and the ability to perform as accurately as possible nodal connections. If the simplest version of a hanging truss with a puff at the bottom is used in the construction of the roof, you can abandon the Mauerlat device, in place of which a narrow leveling board is quite suitable.

The disadvantages of hanging technology are accompanied by advantages. For example, a truss assembled on the ground is much more difficult to transport to the installation site than boards and timber for layered rafters. There are restrictions on overlapping spans: the limit is considered to be 14 m, above which it is unreasonable to install sag-prone wooden beams without intermediate supports.

The rafter legs of the layered group both top and bottom are based on independent structures. The top of them is laid on a purlin structure, which is mounted on the floor beams or on the bed, replacing the Mauerlat on the inner wall. The bottom is either installed on the Mauerlat, or rests against it, catching on the bar with a tooth or a support bar sewn instead of a tooth.

The advantage of layered systems is rightfully recognized as the possibility of overlapping almost any span in size. It’s just that with an increase in the overlapped space, the design becomes more complicated: it is supplemented with struts for a couple with racks, additional runs, coupled with beds, fights.

The layered structure is assembled and mounted longer, because. it is built not from farms, but from individual elements. However, just this scheme has more opportunities to correct the shortcomings of a box or an unevenly settled log house. Because layered rafters are stacked individually, it is possible to slightly change the position and size of the node, in order to eventually form a perfectly aligned slope plane.

The specifics of the manufacture and installation of rafters

It is clear that for the construction of the truss system, lumber will be needed - long-length products of timber processing enterprises with clear geometric parameters. You will need a board or timber, on which, of course, there are no mounting cuts and cuts for installation.

Why are cuts and cuts needed? The fact is that when placed on an edge, boards and beams have too little support area. They are in contact with the Mauerlat with only one vestma in a thin line, because of which, at the slightest load from above, they can tritely “move out” from their position and drag the entire structure with them.

In order to increase the area of ​​\u200b\u200bsupport in the junction of the rafter and Mauerlat, or it and an additional run, a corner cut is selected in a beam or board, a tooth is cut out or a support bar is sewn on. If the top of the rafter is paired with a mirror-opposite counterpart, then for a reliable stop, you will need a gash, the plane of which must be clearly perpendicular to the horizon.

The basic rule in the construction of truss frames is that the platforms selected in the lumber for support are strictly horizontal and vertical. At the slightest violation of horizontality with verticality, stability is lost, structural parts are displaced under their own weight and load, up to the complete destruction of the system.

Note that the nodes of the truss systems are entrusted with the obligation to ensure the possibility of a slight displacement and rotation when the load is exceeded. These movements are necessary in order for the structure to bend slightly, move slightly, but not collapse and maintain stability.

These subtleties should be known both to the master who decided to do the manufacture and installation of rafters with his own hands, and to the owner of the house under construction, who does not want to pay for the poor-quality labor efforts of the builders team. Let's analyze the common options to understand the essence of the process.

Hanging roof frame construction

Consider an example of the construction of a truss system over log cabin baths. The span between the walls is small, it is easier and more reasonable to block it with a hanging structure, the installation of which will be carried out on the bypasses of the ceiling beams - matrices.

The log base is an almost ideal option for installing hanging systems, because. it is easiest to cut it into the horizon, eliminating the need to adjust the rafters in case of a violation of the geometry of the foot. There is no need for a Mauerlat device. However, the puff will have to be moved up in order to bypass the upper crown of the log house and form a useful attic space.

Before performing the installation of the rafters, a phased preparation of the log house is carried out. On both sides of the foot, we align the bypasses according to the lace tied to the nails hammered into the two extreme beams. On top of the bypasses, we cut off the slab so that the edge of each beam ends with a flat horizontal platform.

The surface formed after squeezing the upper bulge of the log along the edges of the beams is aligned to the horizon according to the level. We apply the specified control tool to three or more beams at the same time. If the level is not long enough to carry out such a check, use a long rail or board instead.

After squeezing all the excess, we mark the nests for the rafter tooth. To do this, we again use nails and lace. Note that it is possible to draw nest sampling sites on the bypasses both before the construction of hanging trusses and after. However, it is much more convenient to make nests before making rafters. They will help to carry out the fitting with higher accuracy.

To facilitate your work, it is advisable to find the center of the log house from the side of future tongs. At these points, it is recommended to nail along the control rail, one of the edges of which will indicate the axis of symmetry. You can do without rails if you already have some experience in the construction of roofs.

• We sew two inch boards 10–15 cm longer than the designed length of the rafters at the top with a nail or bolt so that they can rotate around this connecting point.
• On the rail installed in the center of the future tongs, we mark the design height of the truss system. We put one more mark above it - this is the height of the tooth, more precisely, the length of the vertical laid off from the base of the tooth to its top.
• We set the boards sewn at one point to the extreme bypasses so that the corner of each board rests against the future socket under the tooth.
• We combine the connection point of the boards with the upper mark on the rail, which determines the length of the rafters with the tooth.
• From the lower corner of both rafters, we set aside the height of the tooth, return with the template blank to the ground and cut out the tooth according to the markup.
• We return the template blank to its place, install it by inserting the teeth into the sockets intended for them. It may happen that after installation, the top of the workpiece does not match the directions of the rail. Then you need to pull out the nail and adjust the position of the top, be sure to mark a new point.
• After fitting the tops, we draw on both boards vertical line their upcoming joint, measure the size of the crossbar and mark on the scraps of the board the shape of the overlays for the upper joint of the rafters.

If everything turned out exactly and no more adjustments are required, the template is ready. We return with him to the ground. We disassemble the workpiece and make cuts along the marked lines. The parts obtained as a result of fitting and fitting will serve as a standard for the practically in-line production of roof trusses in the required quantity.

We will assemble hanging farms on the ground. Their installation, as well as fitting, should be carried out by at least two people. One master simply can not cope with such work. The performer at the top will install the truss, and the second one will change its position according to the plumb line. The position of each leveled and installed truss should be fixed with temporary struts.

To increase the stability of the system, we will install racks under the rafters:

• Let's mark the matrices under the place of installation of additional supports in an already proven way: we will hammer in a nail from opposite sides and pull the cord.
• We will hollow out nests in the logs according to the markings.
• Let's try a piece of a bar to the installation site. We mark on it the line washed down, taking into account the height of the spike.
• We will make a rack and two linings for attaching it to the rafter.
• Install the support made and fix the position of the truss truss on the other side in the same way. According to the verified scheme, we continue to work until we equip each rafter with an additional support.

To ensure the rigidity of the hanging system, the truss trusses are connected by wind ties - boards, poles or slats nailed from the inside of the structure. On the outside of the truss frame, rigidity will increase due to the construction of the crate.

The rafter legs are attached to the matrices with 200 mm nails or angle brackets. In this regard, metal corners and plates with perforation for fasteners significantly lose traditional methods. To the sidewalls of the rafters we nail fillies made of a board, the width of which is half less material used in the manufacture of rafters.

The length of the filly should be 70 - 80 cm more than the designed width of the overhang. This distance is necessary for their reliable connection with the rafter legs. The fillies can be cut in advance, or without preliminary cuts, you can nail the trimmings of a narrow board to the rafters, and then draw up the line of the eaves. However, the first option is more convenient and economical.

In most cases, as in the example above, fillies must be partially buried in the mats bypass, for this:

• We note in fact the width of the filly at the bypass.
• We make two cuts with a saw according to the markup for 2/3 of the thickness of the filly. We also saw the log between the extreme cuts with a saw. We refine the recess with a chisel, accompanied by a hammer.
• We install the fillies in the formed recesses, sew them with rafters with nails 100 mm long.

Upon completion of the installation of all fillies in the last ones, we hammer in a nail. We pull the control cord and mark where to saw off the excess.

The device of the layered roof frame

In the construction of a truss frame using layered technology, there is much in common with the installation of a hanging structure. The fitting is carried out in almost the same sequence, so it makes no sense to describe the actions twice. The main difference is in the methods of forming the upper node, because the tops of the layered rafters have a support - a ridge run.

If at the top the layered rafters are tritely based on a ridge run, they are laid either with a run, i.e. parallel to each other, or with a strictly vertical joint, similar to the docking of hanging legs. However, in most cases upper part they try to fix it with a notch or a vertical cut with a tight fit to the ridge beam.

There are schemes according to which the layered rafters are based not on the ridge, but on the side run. In such situations, the top is formed according to the hanging principle, and the point of support on the girder is made out with a corner cut.

Let us analyze the most popular option in private construction for the construction of rafter legs based on the lower corner cut and on the ridge run through the vertical gash. Note that the maximum depth of the cut should not exceed 1/3 of the width of the board.

Option for marking with a construction square:

• On the square, we mark the height of the roof and half the span on a scale. These values ​​reflect the slope of the slopes and set the main angles. The proportions must be exactly maintained.
• If further use of the square is not planned, then the delayed points can be marked with screwed bosses or short screws with screws, if planned, then it is better with paint that is removed with a solvent.
• We apply a square to the board laid flat with the side on which the height of the roof is marked. We draw a line according to the indications of the square - this is the line of the upper cut of the rafter - the section of its interface with the ridge run.
• Cut along the marked line with a circular saw. Lay the board for sawing flat, as it should be when cutting in width. Longitudinal cuts are made with setting on the edge.
• From the top of the formed angle, we set aside the length of the so-called diagonal. This is the distance from the junction point with the run to the outer edge of the Mauerlat or upper trim, if equipped frame house.
• We move the square to this point. We draw a line parallel to the first.
• We turn the square over, move it along the workpiece so that 2/3 of the total distance is on the left, and 1/3 on the right. In the picture, these are 8ʺ and 4ʺ.
• The line of a smaller segment will just designate a cut for us.

At the end, we draw the outline of the cornice overhang on the board, cut it along the outlined lines and use the rafter blank made by ourselves to saw the rest of the roof elements.

You can apply the described method without a building square and marking the parameters of the roof on it. It is enough to imagine the process in order to set aside the necessary distances with a conventional drawing tool. However, without experience, you can get confused in the calculations of angles and segments.

To help novice builders, a template has been developed with options for forming corner cuts. It will help you navigate the manufacture of rafter legs from the most common lumber in this area.

In cases of laying rafter legs with notches in the upper and lower parts, it should be remembered that the depth of both notches must be the same so that during construction works the slope of the roof has not changed. Usually, for the device of two equal cuts, an auxiliary bar is used, the thickness of which is not more than 1/3 of the thickness of the board.

The rafter blank is then installed with an edge on the Mauerlat and on the run. The bar is applied on the side in the area of ​​​​the lower and upper nodes to outline the cut.

If the cut is needed only in the lower part of the rafter, and the top will be based on the run with a cut, the board is installed at the bottom on the Mauerlat, and at the top on the run and the bar, so that as a result of cutting, the slope of the slope does not change. At the bottom, a second bar of the same size is applied to the future node and the outline of the future cutting is outlined with it.

The same methods are used to form cuts with a tooth. The difference is only in the form washed down.

The installation of layered rafters begins with the installation of two extreme trusses. The elements are mounted one at a time, their position is carefully checked using a plumb line. Most often, extreme farms are arranged from paired boards, because. they carry more load. They are fixed with temporary spacers, then connected with a cord or rail to indicate the plane of the slope.

Ordinary rafters located between the extreme load-bearing trusses are installed according to the instructions of the laces. If necessary, correct the position of the legs according to the actual situation.

Installation of rafters: how to make and lay rafters for the roof with your own hands

We understand how the rafters are installed. An overview of the technologies that you need to follow for those who want to properly make roof rafters with their own hands.

Do-it-yourself rafters and installing them on the roof

The truss system is the basis of the roof. Therefore, the installation of rafters with your own hands must be approached with a great deal of responsibility. The durability of the roof will depend on how well you perform the calculation and assembly of the rafters.

Rafters take on all the loads: from the roof, snow, wind. Therefore, it is important that the wood for them is ideal. There should be no chips, cracks on it, there should be no knots, traces of rot and other flaws.

Types of truss systems

There are hanging and layered rafters.

The slopes form the slopes of the roof. Supports for them are internal and external walls. Rafters are used mainly for roofing with one slope.

For gable roof they are used only when the structure of the house has an additional supporting wall.

Hanging rafters are good because they can be used for large spans without additional supports. Additionally, crossbars are mounted, which reduce the load on the roof from snow.

Do-it-yourself hanging rafters on the roof are installed if the span is not more than seven meters.

For larger values, it is necessary to additionally mount a vertical spacer (headstock). With a distance between spans of more than nine meters, struts are nailed to the rafter legs at an angle.

It is impossible to imagine a roof truss without additional spacers. Keep this in mind when installing a truss system with your own hands. For example, tightening prevents the rafter legs from spreading, which can occur due to pressure exerted on the roof. But one puff is not enough. The bars under load will begin to sag and may break. To avoid this, crossbars are installed, as well as "grandmothers".

And these conditions apply to the construction of any roof. Even the roof of a frame house built with your own hands needs various reinforcements, despite the fact that the construction of such a roof is one of the lightest.

But before proceeding to the construction of the roof, it is necessary to build a house. You can read about how to build a frame house here. Houses using this technology quickly became popular not only in our country. They are being built in short time, do not require huge cash outlays, have good operational characteristics, environmentally friendly.

The main thing you should pay special attention to when self assembly rafters - the quality of the connections. Let's talk about this in more detail.

Hard connection

To join the rafter legs with the Mauerlat, a rigid connection is often used. Its essence is that at the end of the rafter leg, a cutting is made at an angle of 90 degrees. With this part, the leg rests securely on the Mauerlat.

For a stronger connection, the rafter is fixed to a horizontal bar metal corner or three nails: two - at an angle, one - on top.

sliding joint

With a sliding joint in the Mauerlat, a groove is made into which the rafter leg is inserted. Fastening is carried out using a "sled" with self-tapping screws or nails.

Connecting rafters to each other

You can attach the rafters to each other at the top in several ways. 1 way - butt fastening. To do this, the ends of the rafter legs are overlapped on top of each other. Next is a vertical cut. After that, the rafters are applied end-to-end to each other and fixed with two nails at an angle. Additionally, you can use a metal plate, which is mounted between the rafter legs at the top.

Building rafters: timber

You can build up rafters from a bar by cutting down. To do this, cuts are made at the ends of the bars, with a length equal to twice the height of the section. The height of the cuts should be equal to 1/5 of the height of the timber.

After joining the bars, a bolt hole is drilled in them, the bars are connected.

Rafter extension: board

There are more connection options here. You can overlap the boards. The length of the overlap is approximately the same as half the length of the board.

A secure connection is made using ten nails driven in at a 45 degree angle.

You can join the boards end-to-end, and nail a board on the seam on both sides.

When installing rafters with your own hands, you must constantly ensure that they are located exactly on the same level. It is better to collect farms directly in the attic, as they are very heavy, and it is rather difficult to lift them without special equipment. The dimensions and shape of the rafters are also acquired already at the top.

Before proceeding with the construction of the roof, it is necessary to separate the floor with a ceiling. Ceilings in a house made of foam blocks are part of the overall design of the house, which is not inferior in importance to the foundation and roof.

If you have already made ceilings, then think about it, maybe you want to make a roof under the room. Houses in which part of the volume under the roof is equipped as a living space are called houses with an attic.

Features of the construction of the roof of the house from foam blocks are described in this article. When erecting a roof, it is necessary to strive to reduce its weight so that the load on the walls is small. However, if the house has a reinforced concrete frame, then this recommendation can be deviated from.

Self-installation of the truss system

Installing a truss system is a simple process. First, you need to assemble a farm on the roof. You can do this in any way, depending on its type.

It is convenient to make a truss with a puff at the bottom.

First, a timber or board of the required length is cut off. They will play the role of a puff. To do this, the distance between the walls of the house is measured with a call to the walls themselves. Next, a vertical beam (board) is prepared, which will stand between the puff and the rafter legs. Its length must be adjusted so that when the rafter legs are connected to it at the top point, it turns out required slope stingrays. Make calculations taking into account the fact that the roof should hang at least half a meter over the eaves.

The first farm should be used as a template. A second farm is immediately made on it. All calculations must be recorded. After you have built the rafters with your own hands, you need to install the assembled structures along the edges of the roof and pull the rope between them. When installing intermediate trusses, it is necessary to control their height on it.

Before installing intermediate trusses, it is necessary to make markings along the perimeter of the roof in order to accurately maintain the step between the rafters during installation. When all the roof trusses are mounted, you can proceed with the installation of the battens, counter battens, lay the roofing material and insulate the roof.

Do-it-yourself construction of rafters and the process of installing them on the roof of your house

The rafter system is the skeleton of the roof. So that it does not crumble, you must follow the elementary rules for making wood for rafters and be able to assemble them correctly and

How to put rafters on a gable roof: expert advice

If a decision is made to build a house or a small outbuilding, then it is necessary to protect the building from moisture, and for this you need to make a roof. The roof in its design can be different, but in most cases a gable roof is used. Proven for centuries, it is easy to install and compatible with any type of roofing. Its installation is carried out on the crate, and it is stuffed on the rafters. In order for the roof to last for a long time, you need to know exactly how to properly put the rafters on the roof.

The most actively used material from which rafters are made is wood. Coniferous blanks are usually used, since the structure impregnated with resin allows the wood to retain its qualities for a long time and has a low weight. When choosing a material, it is desirable to avoid boards with knots and large cracks. It is not recommended to use freshly sawn boards and beams for the manufacture of a truss frame, the tree should be dried.

Rafters need to be assembled into a triangular truss, this design allows for optimal rigidity, and it affects the bearing capacity of the entire building.

Components of the roof structure

Rafter systems are divided into two types:

1. Hanging. They are used if the width of the wall along the pediment does not reach 10 m. When using a hanging system, the rafters are leaned on the side walls, and to equalize the load, they are connected by tightening.
2. Layered. They are used in the presence of load-bearing walls, if the width of the wall along the pediment is greater than 10 m. In order to strengthen the rafter system, a vertical beam is placed in the middle, through which the entire load is distributed on the walls, as well as the bed.

The installation of the truss system must begin with the Mauerlat. The place for its installation is planned in the process of building the walls. To do this, you need to lay out a ledge on the outside of the wall, and lay the Mauerlat at the inner edge. For its fastening use:

• binding wire;
• anchor bolts;
• corks made of wood;
• rebar cut into pieces.

The intended place for laying the Mauerlat must be waterproofed, and the beam must be treated with an antiseptic. To reduce the number of joints, the beam must be chosen to the maximum length. If suddenly the length of the beam turned out to be small, you need to make an oblique washed down, and then connect the two parts using self-tapping screws, nails and staples. The length of the cut should be up to 1 meter.

For the manufacture of rafter legs, you need to cut the boards of the required length. A 50 × 20 beam is well suited for this. The connection should not be located in the middle, the required offset is 1/3 of the entire length of the rafters.

For small buildings, truss trusses are easier to assemble on the ground and then lift to the roof.

You need to start putting rafters from the extreme gable trusses. building level the verticality of their installation is controlled. And for the precise installation of intermediate trusses, it is desirable to pull the cord from above and below.

The rafter legs are installed in increments of 0.6 to 1.2 m, and the trusses are fixed to each other with a temporary fixator.

After installing all the trusses, they are fastened with a board in the upper belt, and the latches are removed.

If the span is more than 6 m, and there is a load-bearing wall in the center of the house, then the rafters must be installed differently. Supports are installed in the center, and a ridge beam is mounted on them. Rafters are alternately attached to it. Installation, as usual, begins with the extreme supports. Between them it is necessary to pull the cord to install the remaining rafters in the same plane. An additional beam can be installed between the internal supports, it will reinforce the ridge beam.

Having decided on the angle of inclination and the height of the roof, a template can be made to facilitate marking work. All rafters are of the same length, so you can wash down on the ground, and assemble the prepared structure at the top.

If the rafters are placed without a central run, then they can be overlapped between themselves. The upper points must be fixed rigidly, and a bolt should be installed below.

Having familiarized yourself with how to install rafters, on a small building you can correctly do this work on your own.

How to put rafters on a gable roof: expert advice

How to put rafters on a gable roof correctly: expert advice

Do-it-yourself gable roof truss system - device instructions

A gable roof or gable roof is a roof with two slopes, i.e. having 2 inclined surfaces (slopes) of a rectangular shape.

Gable Roof Frame Effect design features perfectly combines ease of installation and maintenance with reliability and durability. These and many other parameters make the construction of a gable roof a practical and rational solution for private and commercial housing construction.

In this article, we will consider how to make a gable roof truss system with your own hands. For effective perception of the material, it is presented in the form of step-by-step instructions from A to Z, from selection and calculations, to installation of a Mauerlat and a crate under the roof. Each stage is accompanied by tables, diagrams, drawings, drawings and photos.

The popularity of the roof with a house is due to a number of advantages:

• design variability;
• simplicity in calculations;
• natural flow of water;
• the integrity of the design reduces the likelihood of leaks;
• profitability;
• preservation of the useful area of ​​​​the attic or the possibility of arranging an attic;
• high maintainability;
• strength and wear resistance.

Types of gable roof

The installation of a gable roof truss system depends primarily on its design.

There are several options for gable roofs (types, types):

1. Simple gable roof - symmetrical

Simple gable roof - symmetrical The most common version of the roof device due to its simplicity and reliability. Due to the symmetry, a uniform distribution of loads on the load-bearing walls and the Mauerlat is achieved. The type and thickness of the insulation do not affect the choice of material.

The cross section of the beam makes it possible to provide a margin of bearing capacity. There is no possibility of bending the rafters. Supports and spacers can be placed almost anywhere.

A clear drawback is the impossibility of arranging a full-fledged attic floor. Due to sharp corners, “blind” zones appear that are unsuitable for use.

2. Simple asymmetrical gable roof

Simple asymmetric gable roof The construction of one angle greater than 45° leads to a reduction in the amount of unused area. There is an opportunity to make living rooms under the roof. At the same time, the requirements for the calculation are increasing, because. the load on the walls and foundation will be distributed unevenly.

3. Broken gable roof, with external and / or internal fracture

Broken gable roof, with an external and / or internal fracture This roof design allows you to equip a full-fledged second floor under the roof.

Naturally, a simple gable rafter roof differs from the broken line, not only visually. The main difficulty lies in the complexity of the calculations.

The design of the gable roof truss system

Building a roof of any complexity with your own hands involves knowledge of the purpose of the main structural elements.

The locations of the elements are shown in the photo.

Elements of the truss system of a gable roof Elements of the gable roof truss system - scheme 2
Elements of the gable roof truss system - scheme 3

• Mauerlat. Designed to distribute the load from the truss system to the load-bearing walls of the building. For the arrangement of the Mauerlat, a beam of durable wood is selected. Preferably larch, pine, oak. The cross section of the beam depends on its type - solid or glued, as well as on the estimated century of construction. The most popular sizes are 100x100, 150x150 mm.

Truss truss silhouette defines appearance buildings. Examples of farms in the photo.

Roof truss options

Rafter parameters are important. They will be discussed below.

• puff- connects the rafter legs and gives them rigidity.

• Run:

• • Skate run, mounted at the junction of one rafter to another. In the future, a roof ridge will be installed on it.

• • Side runs, they provide the truss with additional rigidity. Their number and size depend on the load on the system.

• Rafter rack- a vertical beam. It also takes on part of the load from the weight of the roof. In a simple gable roof, it is usually located in the center. With a significant span width - in the center and on the sides. In an asymmetrical gable roof - the installation location depends on the length of the rafters. With a sloping roof and the arrangement of one room on attic loft- racks are located on the sides, leaving free space for movement. If there are supposed to be two rooms, the racks are located in the center and on the sides.

The location of the rack depending on the length of the roof is shown in the figure.

Location of the rack depending on the length of the roof

In regions with a significant wind and snow load, not only longitudinal struts are installed (located in the same plane with the rafter pair), but also diagonal ones.

• Sill. Its purpose is to serve as a support for the rack and a place for attaching the strut.

• crate. It is intended for movement during construction works and fixing of roofing material. It is installed perpendicular to the rafter legs.

The presence of a drawing and a diagram indicating the location of all the listed structural elements will help in the work.

The choice of material for rafters

When calculating the material for a gable roof, you need to choose high-quality wood without damage and wormholes. The presence of knots for beams, Mauerlat and rafters is not allowed.

For boards, there should be a minimum of knots, and they should not fall out. Wood must be durable and treated with the necessary preparations that will enhance its properties.

Calculation of the truss system of a gable roof

Calculation of material parameters milestone, therefore, we present the calculation algorithm step by step.

Calculation of the truss system It is important to know: the entire truss system consists of many triangles, as the most rigid element. In turn, if the slopes have different shape, i.e. are an irregular rectangle, then you need to divide it into separate components and calculate the load and the amount of materials for each. After calculations, summarize the data.

1. Calculation of the load on the truss system

The load on the rafters can be of three types:

• Permanent loads. Their action will always be felt by the truss system. Such loads include the weight of the roof, lathing, insulation, films, additional elements of the roof, finishing materials for the attic floor. The weight of the roof is the sum of the weight of all its constituent elements, it is easier to take into account such a load. On average, the value of the constant load on the rafters is 40-45 kg / sq.m.

For reference: The weight of some roofing materials per 1 sq.m. presented in the table

• Variable loads. They operate at different times and with different strengths. Such loads include: wind load and its strength, snow load, precipitation intensity.

In fact, the roof slope is like a sail and, given the wind load, the entire roof structure can be destroyed.

Wind load on the roof

The calculation is carried out according to the formula: wind load is equal to the indicator for the region, multiplied by the correction factor. These indicators are contained in the SNiP "Loads and Impacts" and are determined not only by the region, but also by the location of the house. For example, on private house, surrounded by high-rise buildings, there are fewer loads. A detached country house or cottage is experiencing increased wind loads.

2. Calculation snow load on the roof

The calculation of the roof for snow load is carried out according to the formula:

The total snow load is equal to the weight of the snow multiplied by the correction factor. The coefficient takes into account wind pressure and aerodynamic influence.

The weight of snow, which falls on 1 sq.m. roof area (according to SNiP 2.01.07-85) is in the range of 80-320 kg / sq.m.

The coefficients showing the dependence on the slope angle are shown in the photo.

The scheme for calculating the snow load on the roof

• Special loads. Accounting for such loads is carried out in places with high seismic activity, tornadoes, storm winds. For our latitudes, it is enough to make a safety margin.

Assessment of the condition and bearing capacity of walls and foundations

It should be borne in mind that the roof has a significant weight that can harm the rest of the building.

Determination of the roof configuration:

• simple symmetrical;
• simple asymmetric;
• broken line.

How harder shape roofs, the greater the number of roof trusses and sub-rafter elements is needed to create the necessary margin of safety.

3. Calculation of the angle of the roof

The angle of inclination of a gable roof is determined primarily by the roofing material. After all, each of them puts forward their own requirements.

It should be noted that increasing the angle increases the area of ​​\u200b\u200bthe space under the roof, but also the amount of material. What affects the overall cost of work.

Calculation of the angle of the roof

5. Calculation of the pitch of the rafters

The pitch of the rafters of a gable roof for residential buildings can be from 60 to 100 cm. The choice depends on the roofing material and the weight of the roof structure. Then the number of rafter legs is calculated by dividing the length of the slope by the distance between the rafter pairs plus 1. The resulting number determines the number of legs per slope. For the second number, you need to multiply by 2.

6. Calculation of the length of the roof rafters

Rafter length for attic roof calculated using the Pythagorean theorem.

Parameter "a"(roof height) is set independently. Its value determines the possibility of arranging a dwelling under the roof, the convenience of being in the attic, the consumption of material for the construction of the roof.

Parameter "b" equal to half the width of the building.

Parameter "c" is the hypotenuse of the triangle.

It is worth noting that maximum length timber - 6 m.p. Therefore, if necessary, the timber for the rafters can be spliced ​​(building, joining, joining).

The method of splicing the rafters along the length is shown in the photo.

Methods for splicing rafters along the length

The width of the rafters for the roof depends on the distance between opposite load-bearing walls.

7. Calculation of the section of the rafters

The cross section of the gable roof rafters depends on several factors:

• load, we already wrote about it;

• type of material used. For example, a log can withstand one load, a beam - another, a glued beam - a third;

• rafter leg length;

• type of wood used in construction;

• distance between rafters (rafter pitch).

You can determine the cross section of the beam for the rafters, knowing the distance between the rafters and the length of the rafters, using the data below.

Rafter cross section - table

Dimensions of lumber (beams and boards) for a gable truss system:

• thickness (section) of the Mauerlat - 10x10 or 15x15 cm;

• the thickness of the rafter leg and puffs is 10x15 or 10x20 cm. Sometimes a beam of 5x15 or 5x20 cm is used;

• run and strut - 5x15 or 5x20. Depending on the width of the leg;

• rack - 10x10 or 10x15;

• lying down - 5x10 or 5x15 (depending on the width of the rack);

• thickness (section) of the roof lathing - 2x10, 2.5x15 (depending on the roofing material).

Types of gable roof truss system

For the considered roof structure, there are 2 options: layered and hanging rafters.

Types of roof system: with layered and hanging rafters

Consider each type in detail in order to make an informed choice.

hanging rafters

They are used with a roof width of not more than 6 r.m. The installation of hanging rafters is carried out by attaching the legs to the load-bearing wall and the ridge run. The design of hanging rafters is special in that the rafter legs are under the influence of a bursting force. Hanging rafters with a puff installed between the legs can reduce its influence. The puff in the truss system can be wooden or metal. Often puffs are placed at the bottom, then they play a role bearing beams. It is important to ensure that the puff is securely fastened to the rafter leg. Because a bursting force is also transmitted to it.

The higher the puff is located, the greater the strength it should have.

If the puff is not installed, the load-bearing walls can simply “disperse” from the pressure created by the truss system.

Rafters

They are used in the arrangement of roofs of any size. The design of the layered rafters provides for the presence of a bed and a rack. Lying lying parallel to the Mauerlat takes on part of the load. Thus, the rafter legs seem to be inclined towards each other and are supported by the rack. The rafter legs of the layered system work only for bending. And the ease of installation also tips the scales in their favor. The only downside is the stand.

Combined

Due to the fact that modern roofs differ in a large variety of forms and complexity of configurations, a combined type of truss system is used.

Combined view of the truss system

After choosing the type of truss system, you can accurately calculate the amount of materials. Record the calculation results. At the same time, professionals recommend drawing up drawings for each element of the roof.

Installation of a gable roof truss system

After the gable roof rafters are calculated, installation can begin. We break the process into stages and give a description of each of them. Get a kind of step-by-step instruction containing additional information for each stage.

1. Attaching the Mauerlat to the wall

The beam is installed along the length of the wall on which the rafters will rest.

In log cabins, the role of the Mauerlat is played by the upper crown. In buildings built of porous material (aerated concrete, foam concrete) or brick, the Mauerlat is installed along the entire length of the load-bearing wall. In other cases, it can be installed between the rafter legs.

Splicing the Mauerlat to each other (direct lock with bolts) Since the length of the Mauerlat exceeds standard sizes lumber, it has to be spliced.

The connection of the Mauerlat with each other is done as shown in the figure.

How to connect the Mauerlat?

Washed down the bars is made only at an angle of 90 °. Connections are made using bolts. Nails, wire, wooden dowels are not used.

How to fix the Mauerlat?

The Mauerlat is installed on top of the wall. Mounting technology provides for several ways to mount the Mauerlat:

• strictly in the center of the bearing wall;
• offset to one side.

Mauerlat cannot be placed closer than 5 cm to the outer edge of the wall.

To protect the beam for the Mauerlat from damage, it is laid on a layer of waterproofing material, which most often acts as an ordinary roofing material.

The reliability of fastening the Mauerlat is an important aspect of construction. This is due to the fact that the roof slope is like a sail. That is, it experiences a strong wind load. Therefore, the Mauerlat must be firmly fixed to the wall.

Methods for attaching the Mauerlat to the wall and rafters

Mauerlat fastenings with anchors Anchor bolts. Ideal for monolithic construction.

Mauerlat fastenings with wooden dowels Wooden dowels. Are used for fellings from a log and a bar. But, they are always used with additional fasteners.

Mauerlat fastenings with brackets Staples.

Mauerlat mounts on studs or fittings Stud or fittings. It is used if the cottage is built of porous materials (aerated concrete, foam concrete).

Mauerlat mounts with a sliding mount sliding mount(articulated). The bundle in this way allows you to ensure the displacement of the rafter legs when the house shrinks.

Mauerlat fastenings with wire Annealed wire (knitting, steel). It is used as an additional fastening in most cases.

2. Production of roof trusses or pairs

Installation is carried out in two ways:

• installation of bars directly on the roof. It is not used often, since it is problematic to perform all the work, measurements, trimming at a height. But it allows you to completely do the installation yourself;

• assembly on the ground. Those., individual elements(triangles or pairs) for the truss system can be assembled at the bottom, and then raised to the roof. The advantage of such a system is faster work at height. The downside is that the weight assembled structure roof truss can be significant. To lift it, you need special equipment.

3. Installation of rafter legs

The collected pairs rise up and are installed on the Mauerlat. To do this, at the bottom of the rafter legs, you need to make a drink.

Methods for attaching the rafter leg are shown in the figure.

Methods for attaching the rafter leg

You need to start installing rafter pairs from opposite ends of the roof.

A twine is stretched between the rafter pairs A twine is stretched between the fixed pairs. It will simplify the installation of subsequent rafter pairs. And also, will indicate the level of the skate.

If the rafter system is mounted directly on the roof of the house, then after installing the two extreme rafter legs, the ridge support is installed. Further, half of the rafter pairs are attached to it.

It is worth noting that the opinions of professionals differ on this issue. Some advise using a staggered mounting order, which will evenly distribute the increasing load on the walls and foundation more evenly. This order involves the installation of one rafter in a checkerboard pattern. After part of the rafter legs is installed, the missing parts of the pair are mounted. Others insist that you need to do a consistent installation of each pair. Depending on the size of the structure and the configuration of the truss, the reinforcement of the rafter legs is carried out with props and racks.

Fixing with rafter brackets Nuance. Connect additional elements structures with cutting. It is preferable to fix them with building brackets.

If necessary, you can lengthen the rafter leg.

Methods for splicing rafter legs are shown in the photo.

Methods for splicing rafter legs

4. Installing the gable roof ridge

The ridge knot of the roof is made by connecting the rafter legs at the top.

Roof ridge device:

• Method without using a support bar (see fig.).

Installation of the roof ridge without the use of a support beam

• A method using a rafter bar. Timber is needed for large roofs. In the future, it can become a support for the rack.

• The method of laying on the beam.

Installing the roof ridge by laying on a beam Installing the roof ridge by laying on a beam

• More modern variety manufacturing a ridge knot can be considered the method shown in the photo.

Method for making a ridge knot

• Cutting method.

Installation of the roof ridge by cutting

After the truss system is installed, we make a major fixing of all structural elements.

5. Mounting the roof sheathing

The crate is mounted in any case, and is designed for more convenient movement along the roof during work, as well as for fixing roofing material.

The step of the lathing depends on the type of roofing material, for example:

• under the metal tile - 350 mm (the distance between the two lower boards of the crate should be 300 mm).
• under corrugated board and slate - 440 mm.
• under the soft roof we lay a continuous crate.

Conclusion

As you can see, despite the seeming simplicity, the installation of a gable roof truss system contains many pitfalls. But, based on the above recommendations, you can easily build a reliable structure with your own hands.

Gable roof truss system - calculation, installation, do-it-yourself installation of rafters

Double pitched roof system. The technology of the truss system for a gable roof. Calculation of load and elements (rafters). Installation of the truss system (installation of the Mauerlat,