Simple truss system. Installation of the truss system

When building your house, you will definitely face many difficulties. First you need to draw up a project, then prepare the material, and then proceed to the construction of the building. Each stage has its own characteristics and difficulties, if you do not get to know them in advance, then construction can easily be delayed. For example, the installation of a truss system. The durability of the whole house depends on the correct implementation of this stage. And how to do it right?

At the beginning about the design itself

Installation of the truss system is carried out in a certain sequence. To know how to do the job, you must first get acquainted with the design itself. The roof truss system consists of the following main elements:

• The Mauerlat serves as the lowest "tier" of the truss system. It is a wooden beam located around the entire perimeter of the building. Mauerlat serves two purposes. Firstly, it evenly distributes the load from the rafter system to the walls of the house. Secondly, the Mauerlat allows you to align the base horizontally;
• Rafter pairs are the main element of the entire system. It is he who takes on all the loads, and also connects other components;
• Run. It is a wooden beam. Most often, it is installed up, at the ridge and connects the rafters. Also, in some cases, a bottom run is installed. In this case, it serves as an additional fastening element of the rafter legs;
• Puff. It is mandatory to use it in . The puff fastens the lower ends of each pair together. In some cases, the element may be in the upper part of the rafter triangle;
• Struts, racks. The elements serve as additional support for the rafter legs;
• Filly. Additional element. Mounting the filly is necessary in order for the overhang.

The truss system has both mandatory and optional components. For example, Mauerlat. It is used almost always, with the exception of houses made of wooden beams. Here you can do without an element. In this case, the role of the Mauerlat will be performed by the upper beam.

Some specialists also include a crate in the truss system. This structure serves as a support for the roofing material. In some cases, a solid, and in others, a discharged crate is required. The first option is used for soft roofing.


System types

Rafters are the basis of the entire roof structure. It is they who take on all the loads and transfer them to the walls. If we are talking about a gable roof, and it is this option that is used most often, then the truss system itself can be made in two main versions:

• . Such truss systems are used in cases where the house has a small width. The length of the span should not exceed six meters. The hanging system implies the emphasis of the rafters only on the Mauerlat or directly on the walls. From above, the pairs simply connect to each other, there is no ridge run. From below, the rafters are additionally attached to each other, in pairs, with stretch marks;
• . Such a rafter system is used if a load-bearing wall or column passes in the middle of the house. They serve as a support for the installation of the ridge run. The layered truss system is used in the construction of wide houses.

Often a combination is also used. For example, it is used in the construction of gable roofs. In this case, extensions depart from the main building at a right angle. The main house is covered with a roof using a layered truss system. Side extensions, since they are usually not wide, can be “covered” with a hanging structure.


Installation order

The correct installation of the truss system is carried out in a certain sequence. Much depends on the characteristics and type of roof. The simplest option is a flat roof. In this case, special skills are not required. It is enough just to lay the beams, creating the necessary slope, and install the battens and roofing materials on them.

The second most difficult is considered a gable roof. It is about her and will be discussed. Knowing the sequence in the case of a gable roof, you can easily navigate in other options.

The sequence of actions when installing the truss system is as follows:




At the end of the installation of the truss system, the installation of the crate is carried out. The waterproofing material must first be laid. If this is not done, then the wooden elements will get wet and quickly fail.


There are some features of installing a truss system on a house built of wood. Firstly, Mauerlat is not used in this case. Secondly, the rafters themselves are attached to the upper crown of the walls without fail in a sliding way. This is necessary due to the nature of the wood. It starts to dry out over time. If the rafters are fixed in a rigid way, then the entire system will definitely lead and the roof will simply collapse.

Features of installation of different types of roofs

There are many options for roofing. Each owner chooses according to his preferences and tastes, the features of the house itself are also taken into account. Depending on the type of roof, the installation of the truss system is carried out with some differences, namely:




Gable and shed roofs can be built independently. To install the truss system, you need little skills in carpentry and a clear calculation and planning of your actions. All calculations can be easily done using special programs on the Internet. You can also find installation instructions there.

For other roofing options, quite a lot of experience is required. That is why their construction is most often trusted by professionals. Of course, in this case, the cost of the roof will increase significantly. But you will have a guarantee that everything is done correctly. And this means that the house will be reliably protected from external influences and will stand for more than a decade.

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 structure to support a gable 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 - the optimal shape of the truss 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 is less than 12 m. A design feature is a high spreading 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 is a wooden beam, which usually has a 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 the correct execution of the “hemp”, one 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 the 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 basis of the roof, the reliability and strength of the roof, its ability to withstand precipitation and wind depends on it. The design of the truss system is determined by the shape of the roof and the features of the layout of the house, as well as the materials used. A do-it-yourself truss system is usually made of wood, but other materials, such as a metal profile, can also be used.

Types of rafters and their application

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

1. Laminated rafters based on a ridge run and Mauerlat. They are used in the construction of a single-pitched, simple gable roof, as well as one of the elements of a hip and sloping mansard roof.
2. Sliding rafters - a type of layered rafters used for wooden buildings that give a lot of shrinkage. Their difference is the sliding fastening of the rafters to the Mauerlat, which allows you to compensate for the shrinkage of the walls without deformation of the roof.
3. Hanging rafters - a system of rafters tied with crossbars or puffs, usually used in the construction of a simple gable roof, as well as the upper rafters of a mansard roof. In the hanging rafter system, there is no ridge run, and in the upper part the symmetrical rafter legs rest directly on each other.
4. Sloping rafters, otherwise called angular or diagonal. They are used to make a three-pitched or four-pitched roof, as well as for roofs with complex geometry.

Elements of the truss system

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

• Mauerlat - a beam fixed on the upper plane of the walls around the perimeter of the whole house;
• Beds - support bars laid on internal load-bearing partitions or columns;
• Beams of the ceiling of the upper floor;
• Racks and supports;
• Runs - horizontal support elements laid along the roof axis on racks.

The truss truss consists of the following elements:

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

Narozhniki - short rafters resting on diagonal rafters in a hip roof.

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

Laminated rafter technology

1. Before construction begins, it is necessary to sketch the roof and calculate its dimensions. The cross section and pitch of the rafters, as well as the need to install additional supports and struts, are also determined by calculation.
2. Support elements are laid and exposed: mauerlat, beds and floor beams, racks, ridge and intermediate runs. These operations are described in detail in articles on various types of roofs:
3. Make a rafter template. To do this, take a board with a width corresponding to the estimated length of the rafters, with the same width, but with a smaller thickness - it is lighter and easier to fit exactly in place. The board is applied to the installation site of the extreme rafter with one end to the ridge run, the other to the Mauerlat.
4. At the top of the template mark the top gash. The shape of the cut should be such that the board lies on the ridge run and at the same time fits snugly against the opposite rafter. The depth of the cut should be no more than 1/3 of the width of the board.
5. After sawing out the upper cut, the template is once again applied in place and the lower cut is marked out - it should rest on the Mauerlat, without leaving large gaps. The end of the template is filed at an angle so that the cut is in a vertical plane.

   

6. The resulting template is applied at the installation site of all rafter legs, checking whether it will be necessary to fit in place. If the template fits perfectly (which rarely happens), you can immediately make the required number of rafter legs. If you need to adjust the bottom notch, then only the upper part of each rafter is cut out according to the templates, and the bottom notch is done in place each time.
7. The rafters are placed with the established step calculation. Usually it is from 50 to 120 cm and depends on the type of roofing, namely on its severity, and on the expected snow load. The heaviest coatings are slate and ceramic tiles, but they are rarely used today. More often, the choice is made in favor of more modern, light and reliable materials: metal tiles, ondulin, soft roofing. For them, the pitch of the rafters can be chosen about 100 cm without performing complex calculations.
8. First, rafters are installed from the side of the gables. The rafter leg is supported on the ridge run and the Mauerlat and fixed on two nails 100-150 mm in each attachment point. Having installed the rafter pair, they additionally fasten it: in the upper part with the help of metal plates and self-tapping screws on one side and corners with a stiffener on the other, in the lower part - with brackets or also on the corners.

   

9. After installing the rafters from both gables of the roof, a twine is pulled between them and the rest of the rafters are aligned along it. Rafters are fastened in the same way.

   

10. Install struts, if required by the results of the calculation. The struts are made from the same material as the rafters. A board of suitable length is applied at the desired angle to the rafter and the bottom cut is marked. It is important to consider what the brace will rely on: on the floor beam or on the bed, the shape of the lower gash depends on this. After completing the lower cut, the brace is put in place and the cut line along the rafters is marked. The prepared brace is placed at a distance between the beams and rafters and secured with metal plates or corners.

Roof strut installation

Technology for the implementation of hip diagonal rafters

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

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

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

The roof is a complex and important architectural element of any building. Its construction should be treated with special attention, it must be remembered that the installation of a truss system requires considerable experience in performing such work and a special tool. It is not worth taking on the creation of a roof for those who hold a carpentry and measuring tool in their hands for the first time - the results of the activity can be very negative.

There are two types of roofs, depending on the number and placement of rafter support points, but each developer can, at his own discretion, slightly change the specific design of the truss system. This takes into account the operating conditions of the building, the purpose of the attic space, the climatic zone of the location, the technical parameters of lumber and roofing. Of course, the type of truss system is influenced by the personal experience and preferences of developers.

Before proceeding with the manufacture of rafters, you should decide on their type, method of attachment and linear dimensions. Only in this case, you can be sure of the strength and safety of the structure.

How do various factors affect the parameters of the rafters?

This knowledge will help you make the right decisions both during the manufacture of rafters and during their fixation directly in place. Mistakes in the construction of the truss system are too expensive, you should not show excessive self-confidence.

What influences the choicesizes andwaysmountsrafter

A very important point. The task of any fixation is to ensure the stability of the connection node, while it can be fixed or have one or more degrees of freedom. This cannot be achieved without knowledge of the loads affecting the rafter legs. Loads can be permanent and temporary, dynamic and static, unidirectional and multidirectional.

1. Constant vertical forces. Arise due to the impact of roofing and roof insulation materials. Due to the fact that the rafter legs are located at an angle to the vertical force, they are subject to bending and bursting loads. The magnitude of the forces is determined after the construction of the diagram, on the basis of specific bending and bursting forces, the thickness and width of the boards for the rafters are selected. Fasteners must prevent the spreading of the truss system.
2. Variable vertical forces. Appear in winter, the value depends on the height of the snow cover.
3. Lifting wind forces. As a result of gusts of wind, lifting forces act on the roof. They do not affect the dimensions of the rafter legs, efforts are taken into account only when choosing the type of fixation, it must provide for and hold such loads.
4. Lateral efforts. The value depends on the windage of the roof. As a result of gusts of wind, lateral forces act on the truss system. They increase bending and tearing loads. This feature must also be taken into account during the manufacture and installation of rafter legs.

There are options for rigid fastenings of truss trusses; for this, metal plates, corners, self-tapping screws and nails are used.

Sometimes it is required to use floating rafter connections to compensate for changes in the size of wooden houses. For floating connections, special fasteners and bolts are used. The second allows the rafter legs at the top to turn a little.

Another example of a free rafter connection is a sliding one. It is used on wooden log cabins and makes it possible to compensate for the natural shrinkage of the house.

What elements are used to increase the stability and bearing capacity of the rafters

As a result of the correct choice of the truss system and methods of fixing its elements, the structure must be stable, compensate for natural fluctuations in linear parameters and withstand various loads that occur during operation. To fulfill the conditions during the fixation of the rafters, additional fixation elements can be used.

Runs

Most often they are mounted in the ridge part of the system, the upper ends of the rafter legs rest on them. To increase stability, cuts may be provided. The top connection is rigid or floating on bolts. On large roofs, girders can be installed in the middle of the rafter legs or in other places with critical loads.

vertikaflax racks

They are installed to strengthen the rafters; due to the use of racks, elements can be made from thinner lumber. Vertical racks with their upper end abut against the rafters, and with their lower end against the bed or ceiling beams.

corneraboutpores

Retain bending and expansion forces, universal use. Corner stops can be placed in any places of the rafter leg that cause concerns about strength. Due to such stops, the resistance of the rafters to bending and tearing forces is significantly increased.

Puffs(crossbars)

Purpose - to keep the rafter legs from sprawling, they are used on hanging rafter systems. Most often they are placed in the upper part of the truss; boards with a thickness of about 20–25 mm can be used for manufacturing. The fact is that they work in tension, lumber holds such efforts well. Boards do not work well in compression, quickly bend and lose their original strength indicators.

Knuckleadki

They are used in the upper ridge part of the rafters, due to the use of puffs, the strength of the knot connection increases. Puffs can be made of wood, plywood, OSB or metal.

Bosses(stops)

They have many specific names. They are ordinary pieces of boards 30–40 cm long and 40–50 mm thick, fixed at the bottom of the rafters. They rest against the Mauerlat and do not allow the structure to slip. The use of bosses allows you to perform a rigid connection of elements without sawing the rafters. We talked about the problems that arise in connection with sawing in this article above.

Prices for various types of timber

Options for connecting the ridge knot of the rafter legs

The horse is one of the main and most loaded elements of the truss system. The node has several connection options, you should choose a specific one depending on the general parameters of the roof.

With a large length of slopes, it is better not to use a ridge beam, but instead to put two parallel runs and puff crossbars. This design is easier to do, it is more stable and safe.

For a hanging roof, you should choose the most reliable ways to connect the rafter legs, these systems have a minimum number of additional stops.

Prices for various types of fasteners for rafters

Fasteners for rafters

step by stepwithtruction of the mouthanew rafters

For rafter legs, coniferous boards 50 × 200 mm, first-class lumber, are used. The boards must not have traces of rot or fungus, significant malformations and deep cracks. It is strictly forbidden to use low-quality lumber for the manufacture of the truss system.

To increase the protection of roof elements from decay, it is recommended to use fire protection.

Rafter blanks should be impregnated at least twice, while the material must be dry and clean. Processing is done on a flat area in dry and clear weather.

It can be impregnated with a roller, brush or air gun. It is not recommended to use household hand sprayers - too long and hard. Boards can be lifted up after complete drying of the impregnation.

Our gable roof has a ridge run, vertical supports rest against a bed located on a load-bearing wall in the middle of the building.

Practical advice. If the house is quite high and the boards are heavy, then it is recommended to make an elementary device to protect window openings from damage. To do this, two boards are knocked down in the form of a square, the length and width are selected taking into account the parameters of the opening. The device is installed on the windowsill, and the rafter boards do not damage the foam blocks during lifting.

Prices for fire-retardant impregnations

Preparatory operations

The manufacture of rafters begins with preparatory operations.

Step 1. Raise the rafter boards into the attic. For convenience, place them evenly along the length of the building, put one end on the Mauerlat, and the other on the run bed. First you need to install the extreme rafters on both sides of the roof of the house, pull a thread between them and install and align all the remaining ones along it.

Step 2 Check again the position of the ridge run. It should be located exactly in the middle of the roof. Its displacement by 1–2 centimeters will not affect the strength of the roof as a whole, but it will somewhat complicate the manufacture of rafters and the laying of roofing materials. In addition, an experienced builder may notice a mismatch in the size of the slopes and, accordingly, the asymmetry of the roof. It is recommended to achieve a situation so that the ridge run is located along the line of symmetry, if this is not associated with great difficulties. The final decision is made by the foreman on site and depends on the magnitude of the offset and the amount of work to correct the error.

How to straighten a run?

1. Attach a batten board to the Mauerlat, it is lighter, easier to lift and fix. The second end should lie on the run. The board is nailed to the Mauerlat with an ordinary smooth nail or screwed with a self-tapping screw.
2. Climb to the top of the run and use a tape measure to check the distance from the edge of the run to the Mauerlats installed on opposite walls. Work very carefully, it is advisable to use insurance. Unfortunately, in practice, few people follow the safety rules, but in vain. Falls from height can cause very serious injury.
3. Align the purlin to the center and secure the board. To increase rigidity, fix the same board on the other side of the run.

Now everything is ready, you can proceed to the manufacture and installation of rafters.

Installationrafter legs

If you work alone, then you need to fasten a piece of rail to the run at the place where the first rafter is fixed. A rafter board will be temporarily fixed to it to prevent it from slipping down.

And at this time, you can perform work on the manufacture and preparation for connecting the upper part of the rafters.

Step 1. Lift and install the rafter board in place, clamp it to the previously fixed rail with a clamp.

Step 2 Draw lines to cut out the thrust pad. This is done in two stages. First, draw a horizontal line. To do this, press the rail, square or other even object firmly against the horizontal surface of the run.

Second, draw a vertical line. Now the ruler or square should be pressed against the side surface of the run.

Important. The width of the ruler should be no more than 2-3 cm, it is not necessary to make deep cuts and greatly reduce the width of the rafter leg, it loses its maximum design strength.

Make the same markup at the bottom of the rafter. Only now the ruler needs to be pressed against the Mauerlat surfaces.

Step 3 Remove the board and carefully cut out the seats. You can work with a hacksaw or an electric circular hand saw.

Practical advice. If the cuts are made with an electric circular saw, then it is better to cut in two steps. First cut to the mark, then turn the board over and cut again to the mark. Knock out the cut piece with a hammer, and remove the remaining protrusion with a chisel or chisel. No need to go behind the line with a saw and try to cut off the ledge in one go. This method increases the cut by 3–5 cm, depending on the diameter of the disk, which significantly reduces the bearing performance of the rafter.

Step 4 Install the prepared rafter in place and check the correctness of its manufacture. Do the same operations with the second leg of the farm.

Step 5 Place the rafters with an emphasis on the Mauerlat and the run, pull them together with a clamp in the upper part. Find the middle of the run and transfer the line to the rafters, use a level or building square (only if the plane of the run is strictly horizontal).

Step 6 Saw through two rafters at the same time along a vertical line. The boards must be tightly clamped with a clamp. Pay maximum attention, the saw blade should be perpendicular to the plane of the rafters. If you cut it obliquely, then the ridge joint will not fit tightly, and this reduces the stability of the truss system and is considered an obvious construction defect.

With a lack of practical experience in performing such work, the first leg may have a gap in the ridge part, if it is within 1–2 mm, then there is nothing to worry about. If it is more than 4 millimeters, then you need to correct the element. See which planes of the thrust pads do not allow the upper cut to fit tightly. Approximately indicate the amount of additional cut. Remove the rafter and remove the interfering protrusions. Check the connection again, if there are gaps, repeat the operation. As practice shows, experience appears on the second or third rafter and no further corrections need to be made.

Step 8 Secure the rafter legs firmly in place. For this, it is recommended to use metal plates and corners, it is simple and easy to work with them, the strength fully meets the requirements for the truss system.

For each pair of rafters, you will need one large reshaped plate to connect the ridge knot, two 50x50mm corners for fixing to the run and two 60x80mm corners for screwing to the Mauerlat. The thickness of the metal is at least two millimeters.

In the same way, install the extreme rafters on the other side of the house, pull the threads between them. One at the top and bottom and one in the middle. So that they do not interfere during the manufacture of rafters, make a gap between the thread and the plane of about one centimeter.

Real professionals never make one rafter in the attic of a house. Such an algorithm of work significantly increases the construction time, complicates the process itself and makes it unsafe. It is very dangerous to work with electric tools on unsuitable sites, injuries from them are severe, often causing disability.

If the house is delivered with high quality with exact observance of dimensions and rules, then the rafter legs are made according to one template on the ground. Finished elements are assembled on the roof. This technology increases labor productivity by 3-5 times, at the same time the quality of the rafter system is improved, it is more reliable and durable. Of course, the wages of builders also increase proportionally. They work from the development and receive money not for the time spent in the attic, but for the assembled roof.

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Video - Manufacturing and installation of rafters on a gable roof

The truss system of a gable roof is a simple design that is available for a do-it-yourself device even for a novice developer. It is only necessary to make preliminary calculations, familiarize yourself with the details and stages of the construction of the roof, and calculate the materials needed for installation. When calculating, it should be taken into account that the bearing capacity of a gable roof depends on the influence of loads from wind, snow, and the weight of materials on it.

In order to make the process of building a gable roof truss system as easy as possible for you, below is a detailed step-by-step instruction for installing a truss system with your own hands.

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Requirements for building materials

For the installation of a truss system, the best option would be to use sawn timber from coniferous wood - pine, spruce or larch, grades I - III.

The material for the rafters is taken not lower than grade II, the mauerlat is made from boards or timber of grade II, for racks and girders material of grade II is taken, the crate is made from grade II-III lumber, it depends on the roof. Crossbars, puffs are made of Grade I material. On linings, linings, material of grade III can be used.

Note! Lumber must be dry with a moisture content of not more than 20%. Before installation, it should be treated with flame retardants and antiseptics against fungal diseases.

You need to store lumber under a canopy, providing protection from the sun and moisture. Level the storage area, shift the lumber with linings for ventilation.

For installation, fasteners are required: ties, plates, studs, bolts with washers and nuts, self-tapping screws with EPDM gaskets, 2.8 mm thick, mounting tape, galvanized brackets.

Brackets are used when fastening the Mauerlat, they are fastened with nails or self-tapping screws.

KR corners serve to attach the rafters to the Mauerlat, prevent the rafters from moving.

All fixing material must be made of high quality material and protected against corrosion.

Tools for the construction of the truss system

To install the gable roof truss system, you will need the following set of tools:

• tape measure, different lengths 5, 10, 20 meters;
• markers, pencils;
• cord, for stretching;
• hammers, various purposes, nail puller;
• scissors, for cutting;
• roofing knife;
• putty knife;
• scotch;
• hacksaws, electric saw, electric drill with various drills and nozzles;
• screwdriver with nozzles;
• markings, horizontal and vertical levels;
• rails, rulers;
• mounting foam;
• safety belt and rope - for safe work.

Keep all roofing tools in a tool bag for safety.

Types of truss systems for a gable roof

sent rafters

They rely on the Mauerlat and racks installed on the inner wall, with a step equal to the rafters. To give rigidity during spans of 6 m, struts are additionally placed.

The scheme of the rafters of a gable roof

hanging rafters

If the building is of a small width, it is possible to arrange a truss system when the rafters rest on the mauerlat or walls, without intermediate supports. The maximum span is 9 meters. Such roofs can sometimes be arranged without a Mauerlat. The rafters are installed on the wall, using gaskets, on the rafters in this embodiment, a bending moment acts.

To unload, put wooden or metal lining. They securely reinforce the corner. For hanging rafters of a larger span, a headstock and struts are installed. For hanging systems, the rafters are arranged with a larger section, and the lumber is chosen not lower than grade I II.

Scheme of hanging rafters of a gable roof

Calculation of the truss system

It is possible to determine the cross-section of a gable roof beam in the truss system by collecting all the loads acting on it: the weight of the coating, lathing, snow, wind pressure, precipitation.

Permanent loads can be determined by the weight of 1 m 2 of roofing, battens. It is important that the weight per 1 m 2 of the roof is in the range of 40-45 kg.

Variable loads from snow, wind are calculated according to the tabular values ​​of SNiP normative documents, depending on the height of the building, temperature zone. The load from snow is equal to its weight multiplied by a coefficient depending on the slope of the slope. All these calculations are carried out during the project.

And if there is no project, and the roof is being erected on a small building? You need to look at the construction of a house in the neighborhood, which is being carried out according to the project, the roof area is the same as your building. The gable roof truss system will serve as a model.

Rafter beam dimensions

At the top point, a ridge is laid that connects the rafters. The height of the ridge depends on the slope of the roof. The slope is influenced by the choice of coating material. The minimum dimensions are:

• for tiled roofs, slate 22 gr.;
• for metal tiles - 14 gr.;
• ondulin - 6 gr.;
• corrugated board - 12 gr.

The optimal angle is 35-45 gr. slope, provides a quick discharge of water and snow. In regions with strong winds, the roofs are made flat and then the angle of inclination is within 20-45 degrees.

You can determine the height by the formula: H \u003d 1 / 2 Lpr * tgA. Where A is the angle of inclination, L is the width of the building.

The task is simplified when using a ready-made table. The coefficient depends on the width of the building and the angle of inclination. Multiply the coefficient by 1⁄2 of the width of the building.

The rafters are made from pine or spruce bars, with a section of 50 × 100 mm, 50 * 150 mm.

The size of the rafters depends on the pitch. The pitch of the rafters is smaller, a larger number is installed, the cross section will decrease. The distance between the rafters at a gable roof is in the range from 600 mm to 1800 mm, it all depends on the design of the roof and the materials used for its construction.

The roof does not end at the level of the walls, it is extended 500 mm outwards. The rafter leg can protrude, or a board or bar is built up. In this case, moisture does not fall on the wall, the foundation is not poured.

Step-by-step installation of the design of the gable roof truss system

The gable roof truss system consists of the following elements:

1. Mauerlat.
2. Lie down.
3. Racks.
4. Rafter.
5. Struts.
6. Puffs.
7. Crate.

Mauerlat installation

Mauerlat fasteners to a monolithic reinforced concrete belt

Mauerlat evenly distributes the load on the walls of the building, its installation can be done in several ways:

• fasten to the wall through a reinforced concrete belt with studs;
• studs are inserted into the masonry;
• a simple and common way for simple roofs, fastening with wire rod.

For him, take a bar with a section of 100 × 100 mm, 150 × 150 mm or 200 × 200 mm. Which section to choose depends on the size of the roof and its coverage. The Mauerlat is joined along the length, for this, make a 100 mm cut, 500 mm long, fold the bars and fasten with studs.

In the corners, the Mauerlat is tied with cuts to the floor of the beam, fastened with brackets or bolts. For wooden buildings, Mauerlat is the last crown. On brick walls, make a monolithic reinforced reinforced concrete belt, with a section of 400 × 300 mm. Align the pins with a thread of 12 mm in diameter along the belt, through 120 mm, for fastening.

Drill holes with a diameter of 12 mm in the Mauerlat, lay them so that the pins go into the holes. Tighten with nuts from above. Previously, we lay two layers of roofing material or roofing felt under the bar. On the outside of the wall, lay the Mauerlat with bricks. Laying the Mauerlat on a horizontally and vertically even base. It is necessary to check the horizontal level of the surface. Check diagonals. Align with pads if necessary.

Installation instructions for beds, racks, rafters, struts and puffs

Do-it-yourself do-it-yourself installation of a gable roof truss system is carried out in the following order:

1. To carry out the installation of the bed, with the sent rafters.
2. Mark the installation step of the rafter legs.
3. Prepare according to the size of the rack.
4. Install them, if necessary, unfasten them with spacers.
5. Lay a run. Check geometry. Install fastener.
6. Try on the first rafter leg, mark the cutting points.
7. Mark the points and install the rafters at the beginning and end of the roof, pull a cord between them in order to align the rest of the elements with it.
8. Having installed the rafter leg, we attach it first to the Mauerlat, then to the ridge run, to each other.
9. Screw every second leg with wire to the Mauerlat.

The fastening of the rafters to the Mauerlat is done with the help of notches, thrust corners and a hemmed support bar. Reinforce with nails or staples.

Methods for attaching rafters to the Mauerlat

Install the support posts on the beds or linings and linings. A bed is a beam 50 × 100 mm or 50 × 150 mm, laid on the middle wall along a roofing felt lining. Place brick columns under the lining, 2 bricks high.

The rafter legs are connected to each other on the ridge. Consider the common connection nodes of the truss system:

1. They make cuts at one leg and washed down at the other. Insert one leg into the cut of the other and fasten with a bolt.
2. Install overlays, wooden or metal.
3. With the help of cuts in the run, they are fixed with nails or bolts.

Methods for connecting rafters on a ridge

For the stability of the roof to wind loads, puffs, struts and runs are installed. The tightening is a bar 100 × 150 mm, runs and struts are made from a bar 50 × 150 mm or 100 × 150 mm.

With the installation of contractions, the reliability of the rafter design increases. The sections of the beam are the same as the rafters. They are attached to the legs with bolts or nails. The bracing device adds rigidity to the structure. They are installed tightly, to the surface of the rafters.

Lumber has a standard length of 6 m. Rafters can be longer. Then you need to connect them. There are several connection methods:

1. Fasten by applying bars on both sides at the junction, connect them with nails in a checkerboard pattern.
2. Overlap, one part of the rafter to another, at a distance of 1 meter, fasten with nails in a variable order.
3. Run a cut obliquely, cut out part of the legs of the rafters, connect them, reinforcing them with bolts.

Lathing device

A crate is laid along the roof rafters. It serves to distribute the load from the roofing material, snow on the rafters. It plays the role of an air gap between the roof and the truss system.

The design of the crate depends on the accepted roofing material:

• under the soft tiles, make the crate continuous, an anti-condensate film is laid on the rafters, it is pressed on top with a counter rail, the crate is nailed onto it, then the OSB boards and the lining carpet, we lay the tiles on top.
• under the roof of the corrugated board, the crate should be sparse. The step of the lathing depends on the brand of corrugated board, its thickness and the angle of the roof.
• make a crate for standard slate in increments of 500 mm from a bar 75 × 75 mm or 50 × 50, as well as boards from 30 × 100 mm. It is necessary to take into account the design features of the roof, with the final choice of a suitable option.

The lumber from which the crate is made is pine of the first or second grade. It is advisable to take a width of no more than 14 cm. With a width of more, the boards can warp and damage the roofing. The length of the nails should be three times the thickness of the crate. Lay boards along the ridge. Set the first board of greater thickness to the height of the roofing.

To arrange a continuous crate along the slope of the roof.

With the first layer, lay a board along the ridge from it at a distance of 500-1000 mm next, and so on. With the second layer, lay the crate in the direction along the rafters. Arrange the joint between the boards only on the rafters in a run. The nail is sunk completely with the head into the pulp of the wood.

Cornice overhangs

Arranged to protect against precipitation, play an aesthetic role. Eaves overhangs suit tightly without gaps. The final stage in the construction of the roof.

Scheme of the device of the eaves overhang of a gable roof

Gable

The gable roof has two gables. They have the shape of a triangle, with the apex at the ridge and the sides coincide with the slopes of the roof. Gables support the rafters and enclose the attic space. Protect from wind and precipitation, give stability to the roof.

In wooden buildings, the pediment is made frame. In brick buildings, frame or brick. Gables made of brick or gas block are erected before the roofing device. They require very precise execution.

Frame gables fit into the finished opening when the truss system is already assembled.

The frame is made of bars or boards. The frame elements are connected on spikes or to the floor of a tree, all fastened with nails. They are sheathed by nailing boards, lining or siding, maintaining the color in the decoration of the facade of the building. For the device of a window opening, an additional frame is made under it according to the size of the window. If the attic is insulated, then the pediment also needs to be insulated. Insulation is laid in the middle of the frame. A mineral wool insulation with reduced flammability is used. From the outside, the frame is upholstered with a hydro-windproof film or a windproof membrane, from the inside, a vapor-tight film or a vapor-tight membrane is nailed under the finishing material.

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