Roof strut. How to install a gable roof truss system - a step-by-step guide. What elements are used to increase the stability and bearing capacity of the rafters

The rafter system is the basis of any roof. The complexity or accessibility of the roof structure depends on the type of roof chosen. Today we will talk about the simplest option - the rafter system for a gable roof. Experienced specialists tell about the structure of the roof frame, the features and functions of its elements, and how the truss system of a gable roof is made with their own hands.

Gable roof: types and benefits

Recall that a gable roof is a type of roof consisting of two planes (slopes) connected at an angle of a certain degree. It can be simple (symmetrical or asymmetric) and complex - broken.

The rationality of choosing a roof of two slopes is determined by its following advantages:

• Profitability and simplicity of erection, in comparison with other roof structures.
• Ease and availability of service at any time of the year.
• Reliability and durability against wind, snowfall, hail and other natural influences.
• The possibility of arranging the attic.
• Better hydro and thermal insulation.

The necessary theoretical minimum for the construction of the truss system

The pitched roof structure is made of metal or wooden beams. Metal is a more "problematic" material. It makes the entire roofing system heavier, cools down and heats up quickly, is more difficult to install and requires the use of professional welding equipment. Based on this, in the construction of private houses (especially with their own hands), wood is mainly used.

There are two main options for the implementation of the truss system for a gable roof - a hanging type device (each rafter leg has two points of support) and a layered method (the rafters are connected at the bottom by a puff, forming a triangular truss, a carrier beam is installed in the middle). A layered structure is necessary if there is a distance of more than 10 meters between the bearing walls. Look at the image:

What does the system of truss elements consist of? Imagine a 3D projection. The skeleton of the roof consists of a mauerlat (rafter base), rafter legs, a ridge, racks, girders, lying, puffs, struts and battens. Mauerlat, lying and puffs are the lower parts of the system on which the entire future roof is being built. First, take a look at the illustration below, and then consider each element separately:

Mauerlat - the basis of all foundations

Mauerlat is a bar made of solid wood (mainly coniferous species) with a cross section of 10-15 cm. These are the optimal dimensions for the required strength and durability of the entire roof structure. The beam is laid on the load-bearing walls of the house to redistribute the spacer load on them.
There are two ways to install the bars of the truss base - with the transfer of load to the walls and without the transfer of gravity. The choice of mounting option for the Mauerlat should depend on the severity of the roofing system, the coating, the thickness of the load-bearing walls and the perimeter of the roof.

In the latter version, the Mauerlat is placed in a pocket, closer to the inner edge of the wall, and fastened to wooden corks with staples (each cork corresponds to the size of a brick and is part of the top row of brickwork).

The bars that take the load are mounted on the load-bearing walls from above with the help of anchors. Masters advise laying a rigid frame on a concrete base in the form of a belt in the wall. High-quality waterproofing is necessarily laid under the Mauerlat.

Details can be found in the video:

Lying - Basic Load Distributor

Lezhen performs functions similar to Mauerlat, and has the same dimensions. Beams are laid on internal load-bearing walls to evenly distribute loads from vertical struts and struts.

See the illustrations for the installation master class:

Rafter legs - ribs of the roofing skeleton

Rafters can be called the main component of the roof frame. This element cannot be left unused or replaced by another part. The legs of the rafters are wooden beams, the cross-sectional size of which can vary from 5 to 15 cm. The rafters rest on the Mauerlat and are interconnected by a ridge.

The installation process of the rafters can be seen in this video:

Skate - a small nuance with great meaning

The final element of the junction of two slopes is called the roof ridge. This is a rib located vertically at the highest point of the roof. A ridge run is mounted at the junction of the rafters. After that, the roof ridge is installed on it. This element fastens the rafters, performs a ventilation function and gives the roof aesthetics.

Racks - receivers of the main loads

Racks are powerful beams that take part of the load of the truss structure. They are installed vertically, usually in the center of the truss. If the project provides for an attic, then the racks are placed on both sides, closer to the roof slopes. When the attic is divided into two rooms, the racks are placed both in the center and on the sides.

Runs - rafter support

Ridge and side runs serve as a stiffener for roof trusses. The greater the load on the system (snowy winters, heavy roofing, large roof area, etc.), the more purlins should be installed on the roof slopes.

Tightening - truss element connector

This structural detail performs the function of fixing the rafters at the base. Thus, a rafter triangle is formed - a farm. Puffs may not be installed in layered systems.

Struts - the strength of the structure

The struts serve as a support for the uprights and strengthen all structural elements. Experts recommend installing struts at an angle of 450. This increases the strength of the system and protects it from deformation under the influence of snow masses and wind.

Lathing - the basis for a roofing cake

Lathing - horizontal wooden slats with a section of 40-50 mm, located on the slopes perpendicular to the rafters. The main purpose of the crate is to fix the roofing material. The frequency and thickness of the battens depends on its type. In addition, the crate helps to move materials during the roofing and serves as an additional element of structural strength.

Overhang elements - final moments

The edge of a roofing system is called an overhang. This is a protrusion of the rafter system above the wall by about 40 cm. The overhang box consists of the following elements: filly (slats connecting with rafters), frontal and cornice boards. The purpose of the overhang is to protect the walls from getting wet during rains and melting snow.

A step-by-step guide to installing a gable roof truss system

To get started, we suggest that you familiarize yourself with the illustration that we have prepared for you:

And now consider the three main stages of the process of installing a simple gable roof truss system:

Stage 1: Calculations and drafting

Work should begin with the preparation of the roof project. It will contain all sizes, shapes and types of fasteners of structural elements. To create a quality project, you need to make the following calculations:

1. Calculation of constant and variable loads on the truss system. Constant loads include the weight of the roof and finishing materials (the attic is also taken into account additionally). Variable loads are the force of wind, rain, snow, etc. The maximum load can be considered as the main load of up to 50 kg per square meter of roof, and the variable load can be up to 300 kg (taking into account possible snow blockages).
2. Accounting for seismic activity, storm winds and features of the location of the house. For example, if the house is surrounded by other buildings, then the load on the roof is significantly reduced.
3. The choice of the angle of inclination of the gable roof. When calculating the angle of inclination, the following factors are taken into account: the higher the angle, the more materials will go to the roof (and money, respectively); the slope depends on the roofing material - the softer the roof, the smaller the angle of inclination (for example, for soft tiles, an angle of 5-200 is selected, and if you use slate or ondulin, you must select a slope of 20-450).
4. Calculation of the pitch and length of the rafters. The step length between the trusses varies from 60 to 100 cm. The heavier the roofing, the more often the rafters need to be distributed. To calculate the length of the rafter, we use the Pythagorean theorem, taking the rafter leg as the hypotenuse of the triangle. The first side will be considered half the width of the house, and the second - the selected roof height. Then we add another 60-70 cm of margin to the hypotenuse we found.

When all calculations are made, you need to make a drawing of parts, connections and the entire project as a whole.

Stage 2: Acquisition and preparation of the necessary materials and tools

For work, it is necessary to purchase lumber, according to calculations, bolts, corners, anchors and other connecting parts, and prepare the appropriate tools (drills, levels, meters, jigsaw, etc.). Wood for load-bearing beams and rafters must be solid and of high quality - knots and wormholes are unacceptable.

Antiseptic, anticorrosive and fireproof wood treatment is a must at this stage. You can start working with the material one day after processing.

Stage 3: Installation of the roof truss structure

It is better to mount the roof frame in dry, non-windy weather, so as not to encounter additional difficulties during operation. At this stage, we will dwell in more detail and consider step-by-step instructions for installing the truss system.

Installing the truss system: a step by step guide

Step 1. Laying the Mauerlat and the bed. There may not be a bed if there are no more load-bearing walls inside the house. Before laying the Mauerlat on the walls, it is necessary to lay a waterproofing material, for example, roofing material. We measure the tape of the desired width, cut it off and lay the waterproofing on the edge of the wall (where the frame will be installed).

We mark the beams of the desired section and length, trim and begin to form the base frame. Mauerlat should be located on the outer edge of the wall (if a hanging structure is planned) or in a special niche on the wall in front of the threshold (if the roof system is layered). The beds under the racks are laid on the internal load-bearing partitions. The Mauerlat is attached to the wall and wooden plugs with brackets, studs and anchors.

And we invite you to familiarize yourself with the illustration that we have prepared for you:

When laying the frame along the entire length of the wall, we may encounter the need to connect the base beam. They should be performed by cutting the bars at an angle of strictly 90 degrees. Fastening is carried out with high-quality bolts.

How not to damage bricks or blocks when lifting roof boards?

Choose the edge of the wall through which it is most convenient to feed the beams for the roof frame. This edge must be protected with a wooden square. Two trimmings of a rough board about a meter long will do, which need to be knocked together at a right angle. Put the square on the outer edge of the work wall. Now you can lift the boards without fear of damaging walls or window sills with them.

Step 2 Installation of rafters. The first step is to install the extreme rafters. In order for the rafters to be held evenly, we install the racks in the center. We attach the racks to the Mauerlat using an iron corner and self-tapping screws. This temporary part is removed after the installation of all rafters. We fasten the extreme rafters with crossbars and install a ridge run. Mounting type - metal corner, self-tapping screws and studs.

The illustration shows the process of mounting the rafter legs and attaching the rafters to the run:

But how to attach the rafters to the Mauerlat:

Between the extreme farms, it is imperative to stretch the construction thread along which we will level all the slope rafters.

Now we mount all the truss elements according to a pre-marked scheme. We join the rafters over the ridge run.

For more information about the process of installing rafters, see this video:

A system of special racks will help strengthen the rafter legs. On the Mauerlat, wooden bars are fastened from boards of the same thickness as the rafters. The bars must be fixed in increments equal to the selected distance between the rafter legs according to the markup. The length of each board is approximately 40 cm. These racks will transfer the load to the power plate and load-bearing floors. The bars must be fixed to the base with steel corners. Now the rafter legs need to be installed so that one side of each is adjacent to the rack. Then, on the other side of each rafter, we fasten the same rack and grab all three parts with 12 mm studs.

After mounting all the legs of the rack, they are cut flush with the bevel of the rafters from the side of the street. From the inside, an empty corner is formed between the uprights, which must be closed with a wooden triangle (you can use trimmings from bevels).

All rafter legs should be additionally strengthened with crossbars, racks, struts and the joints should be reinforced with metal plates. The full process of strengthening the rafters can be viewed on the video:

Step 3. Waterproofing and crate. On the finished rafter ribs, you need to lay a high-quality waterproofing vapor-permeable material under the crate. The entry of the insulating sheet (sheet to sheet) is 15 cm. A counter crate of wooden battens is stuffed onto the waterproofing along the ribs of the rafters. From above, a crate of the same rails is installed perpendicular to the rafter legs.

When installing the frame, it is necessary to take into account the presence of a chimney and the obligatory ventilation of the ridge. The distance between the boards of the crate is on average 300 mm. This scheme is suitable for all types of solid roofs. When choosing a soft roofing material, the crate is made of solid sheets of moisture-resistant plywood.

The rafter system is ready. Now it's the turn of the installation of roofing material, internal insulation of the roof and the arrangement of the attic (if such is provided for by the project).

So, it's time to answer the main question of our topic: is it worth doing it all with your own hands? Do not believe anyone who tells you that it is easy and simple. But if you have golden hands and a great desire to make a high-quality roof "for yourself", then go ahead! We wish you good luck!

Properly designed and assembled according to technology, the roof serves as a barrier that prevents cold air and moisture from entering the house. Outside, with the naked eye, we see only a small part of the structure - the roofing. But the roof frame, which is the most important component, performs the main supporting functions and absorbs the effects of wind and snow loads.

So that it does not deform as a result of operation, it is necessary to correctly calculate the cross-sectional value of its elements and determine the distance between them, taking into account the weight of the roofing material, slope and climatic conditions. In this article we will tell you what the gable roof truss system of a house is, what it consists of, how it is designed and assembled by hand.

The truss system for a gable roof of a house is a system of interconnected supporting elements, which together form the frame of the structure.

It is made of wood or metal in accordance with the calculation of the loads that will affect them during operation. The roof truss frame performs the following functions:

1. Gives roof slopes the necessary slope. The traditional shape in the form of an equilateral rectangle of a gable roof is given precisely by the truss frame, which forms a slope between the base of the roof and its ridge. The angled surface allows snow and water to slide freely off the slope.
2. Distributes the load from the weight of the roofing cake. The weight of the roofing cake, taking into account the snow load, can reach up to 500 kg / m2, so the gable roof is subjected to intense load, especially in winter. The rafters of a gable roof evenly distribute the weight that falls on them, and then transfer the load to the load-bearing walls and foundation of the house.
3. Serves as a basis for fixing thermal insulation and roofing material. The rafter frame of the roof serves as a kind of skeleton of the structure around which its “body” is built. Thermal insulation should be installed between the rafter legs, and a roofing covering is fixed on the crate, which protects against moisture penetration.

Please note that the design of the gable roof truss system is quite complicated to design and assemble, especially if the master does not have enough experience. Indeed, in order for it to be able to withstand heavy loads, it is necessary to correctly calculate the cross section of the rafters and the pitch of the rafters, taking into account the slope and length of the slopes, the roofing material used, and also draw up a drawing according to which the assembly will be performed.

Types of truss systems

Rafter systems differ in many factors, their composition depends on the layout of a wooden or brick house, the total weight of the roofing pie, the material from which the frame is made, and the type of roofing.

An important characteristic of the design is their bearing capacity, which determines how much weight they can withstand without deformation. According to the characteristic features, the following types of truss systems are distinguished:

Layered

A rafter frame of a layered type is a frame whose rafters have 2 points of support. The upper end of the leg rests on a ridge run, mounted on vertical posts fixed to the inner wall. And with the lower end it is installed on the Mauerlat.

The assembly of a rafter system of a layered type on a gable roof is possible only if there is at least 1 load-bearing partition or capital column inside the house. Such a construction is often called non-thrust, because the second fulcrum of the rafters compensates for the bursting load on the walls of the house, which is assumed by the hanging frame installation scheme.

Rafter legs of a layered type experience only a bending load, which can be eliminated by various struts. The layered truss system allows you to cover houses up to 14 meters wide.

hanging

The hanging truss system is distinguished by the fact that its rafters rest only with their lower end on a Mauerlat beam mounted on external load-bearing walls. The upper end of the rafter legs of this design does not rest on anything, but, as it were, hangs in the air, which causes 2 types of load: bending and bursting.

The bursting load of such an arrangement of elements on the outer walls is so great that it has to be compensated with the help of numerous crossbars and ties, due to which the rafter pairs are tied together.

The device of a gable roof with hanging rafters consists of triangular trusses, the rigid form of which is not subjected to loads. It is believed that the complexity of the hanging circuit is much higher.

Do-it-yourself do-it-yourself rafter system of a gable roof is mounted without difficulty, if you correctly calculate the pitch of the rafters, that is, the distance between the rafters and the size of their cross section.

Combined

Combining the best of both systems, it is recognized as the most reliable. It is used in cases where, indoors, not walls, but columns are used as a support inside the house. Then the hanging and layered rafters can be alternated to strengthen the structure with additional elements, without increasing the consumption of building materials.

Important! A sliding rafter roof is another type of frame, which differs in that the rafter legs are mounted on the Mauerlat not with a rigid mount, but using a movable support. The sliding mount allows the roof to change dimensions within the power reserve during the shrinkage of a wooden house.

Design

The device of the truss system of a gable roof of any of the listed types is a combination of auxiliary and supporting elements. They evenly distribute the weight of the roofing cake, and also compensate for the bursting and bending loads that occur between them.

The cross section, length and pitch of the rafters are determined using an engineering calculation that takes into account the weight of the roofing pie, the climatic conditions in the construction region, and the slope of the structure. The composition of the truss frame of a gable roof usually includes the following elements:

1. Mauerlat. Mount the Mauerlat beam on the outer walls of the house, on which the roof slopes rest. It serves to soften the pressure on the supports and evenly distribute the load from the weight of the roofing cake. It is made of a durable beam with a section of 150x150 mm or 200x200 mm and is attached to the upper belt of the walls using anchor bolts or long metal studs.
2. Sill. This is an analogue of the Mauerlat, only it is installed on internal load-bearing walls, and vertical stands must be placed on it for mounting a ridge run.
3. rafter legs. This term refers to the elements of the frame, which are made of boards with a cross section of 150-40 mm and are installed at an angle to the base of the roof, forming the angle of inclination of the slope. What to do the distance between the rafters, their length and thickness is determined by calculation, taking into account the total load to which they are subjected during operation.
4. puff. A puff is called beams that are placed horizontally and connect the legs of one rafter pair to each other in order to reduce the bursting load on the outer walls of the structure. A crossbar is a puff installed under the very ridge of the structure.
5. Racks. A stand is a vertical beam placed on a bench to support a ridge run. It is easy to determine what distance should be between the racks, because it repeats the step of the rafters.
6. Struts. Diagonally located supports that support the rafter legs in the middle or at the bottom, preventing their deflection, are called struts.

Please note that only the calculation of temporary and permanent loads to which they will be subjected during operation can determine how to properly position the elements of the truss system. Calculating the total weight of the roofing cake helps determine the correct distance between the rafters, calculate their length and the required thickness.

The calculation of the gable roof truss system is based on the fact that in the frontal dimension it has the shape of an equilateral triangle, the sides of which can be easily calculated using simple trigonometric formulas.

These simple calculations help determine the optimal distance between the rafters, their thickness and length. The design calculation is performed in the following sequence:

• Determine the design and slope of the roof. There are various ways to choose the type and slope of the roof structure. This parameter depends on the climatic conditions and performance characteristics of the selected roofing material.
• Determine the total load on the structure. To do this, they sum up the constant loads (the weight of the roofing, their weight of the frame, thermal insulation and ceilings) with the temporary loads (snow load, wind load), multiply by a correction factor that takes into account the slope of the slopes, and then add 10-15% to this figure to the frame had some margin of safety.
• Calculate the length of the rafter legs. To do this, use the Pythagorean theorem, because the truss truss is an equilateral triangle. It turns out that the square of the length of the rafter leg is equal to the sum of the squares of the height of the blood and half the length of the laying. Knowing how to calculate the length of the rafters, you can calculate the height of the ridge.
• Determine the section of the elements. The optimal section of the elements is selected according to the tables in accordance with the length of the rafter legs and the distance between them. The higher these indicators, the thicker the rafter should be.

Remember that before you calculate the rafters on the roof, you need to decide on the basic design parameters. In particular, it is necessary to know exactly the height of the ridge and the slope of the roof, as well as the dimensions of the room to be covered. The result of the calculation of the roof elements should be a detailed diagram of the truss system, reflecting their dimensions and the angles between them.

We calculate the angle of inclination

The angle of inclination of the slopes is selected not depending on aesthetic preferences, but based on weather conditions, taking into account the roofing material. Steeper slopes of 40-45 degrees are built in areas with a large amount of snow cover, and more gentle slopes of 10-20 degrees in places with strong gusty winds.

Keep in mind that the steeper the slope, the higher the consumption of materials, the greater the total cost of the roof. Be sure to take into account the requirements of the material:

1. Tiles, slate require a slope of at least 22 degrees, otherwise, precipitation seeps through the joints between the elements.
2. The metal tile is laid at an angle of at least 14 degrees, as it suffers greatly from gusts of wind, it can deform or even fly off.
3. Soft roofing allows a slope angle of up to 5-10 degrees, making it possible to cover slopes of any geometry with it.
4. Ondulin is considered one of the most reliable materials and can even be used for roofs with a slope of less than 6 degrees.
5. Profiled sheets cannot be laid at an angle of less than 15 degrees, however, it is advisable to treat slopes even with an acceptable slope with a sealant for better waterproofing.

Assembly technology

Before mounting the roof frame, it is necessary to calculate the parameters of its elements, based on the calculation of the total load on the structure, and also create a detailed drawing reflecting its results.

Having a frame diagram in front of you, it is much easier to qualitatively install the gable roof truss system. The assembly technology of the structure implies the following sequence:

1. First, a Mauerlat is laid on the upper belt of the outer walls, on which the slopes will rest, and a bed is mounted on the inner partitions, if the system is layered. These elements must be firmly fixed with anchor bolts or studs.
2. Then the rafters are fastened. They are fixed with nails to the Mauerlat, and are also interconnected using a metal lining. It is worth recalling that in the rafters they make a drink under the Mauerlat beam, and not vice versa. First, the installation of rafters located on the edge is carried out in order to set the level along which the rest of the pairs will be aligned.
3. After installing the rafters, auxiliary supporting elements should be installed that will support them - struts, puffs, contractions. In order to more reliably fix the crossbar, its end is made with a protrusion half the thickness of the beam and it is hemmed to the rafters, fixing it with nails in several places.
4. A crate is nailed over the rafter legs, on which the roofing material is fixed. The material and pitch of the lathing is selected in accordance with the characteristics of the roofing material and the slope of the roof.

Remember that a well-designed and well-assembled truss system is a guarantee of strength, reliability and durability of a gable roof. Therefore, do not neglect the help of professional roofers and designers when creating a roofing design for your home.

Video instruction

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

The design of the gable roof truss system

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

Now about the components of the system and their purpose:

• Mauerlat - a beam that connects the roof and walls of the building, serves as a support for the rafter legs and other elements of the system.
• Rafter legs - they form the inclined planes of the roof and are the support for the crate under the roofing material.
• Ridge run (bead or ridge) - combines two roof planes.
• A puff is a transverse part that connects opposite rafter legs. Serves to increase the rigidity of the structure and compensate for bursting loads.
• Beds - bars located along the Mauerlat. Redistribute the load from the roof.
• Side runs - support the rafter legs.
• Racks - transfer the load from the runs to the beds.

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

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

With hanging rafters

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

The hanging type of gable roof rafter system is good because in most cases there is no need to install a Mauerlat, and this makes the installation of rafter legs easier: no need to make cuts, just mow the boards. To connect the walls and rafters, a lining is used - a wide board, which is attached to studs, nails, bolts, crossbars. With such a structure, most of the bursting loads are compensated, the impact on the walls is directed vertically downwards.

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

Gable roof truss system for small houses

There is a cheap version of the truss system when it is a triangle (photo below). Such a structure is possible if the distance between the outer walls is not more than 6 meters. For such a rafter system, it is possible not to calculate the angle of inclination: the ridge must be raised above the puff to a height of at least 1/6 of the span length.

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

The photo also shows how to grow rafter legs to create a roof overhang. A notch is made, which should go beyond the line drawn from the inner wall upwards. This is necessary to move the incision site and reduce the likelihood of a rafter breaking.

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

For mansard roofs

Option with the installation of a crossbar - used when. In this case, it is the basis for filing the ceiling of the room below. For reliable operation of this type of system, the crossbar notch must be hingeless (rigid). The best option is semi-pan (see the picture below). Otherwise, the roof will become unstable to loads.

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

With such a scheme, almost the entire load falls on the rafters, therefore they must be taken with a larger section. Sometimes the raised puff is reinforced with a suspension. This is necessary to prevent it from sagging if it serves as a support for ceiling sheathing materials. If the puff is short, it can be secured in the center on both sides with boards nailed to the nails. With a significant load and length, there may be several such insurances. In this case, boards and nails are also enough.

For big houses

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

With such a long span (up to 14 meters), it is difficult and expensive to make a one-piece puff, because it is made from two beams. It is connected by a straight or oblique cut (picture below).

For reliable docking, the junction is reinforced with a steel plate mounted on bolts. Its dimensions should be larger than the dimensions of the cut - the extreme bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the cut.

In order for the circuit to work properly, it is necessary to correctly make the struts. They transmit and distribute part of the load from the rafter legs to the puff and provide structural rigidity. Metal strips are used to reinforce the connections.

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

With rafters

In gable roofs with layered rafters, their ends rest on the walls, and the middle part rests on load-bearing walls or columns. Some schemes burst walls, some do not. In any case, the presence of a Mauerlat is mandatory.

Bezporny schemes and knots of cuts

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

The simplest non-spacer scheme of the truss system is shown in the photo below. In it, the rafter leg rests on the Mauerlat. In this embodiment, it works on a bend, without bursting the wall.

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

The top of the rafter legs is laid on the ridge beam without fastening it to the opposite rafter. Two shed roofs are obtained according to the structure, which adjoin (but do not connect) one with the other in the upper part.

It is much easier to assemble the option with rafter legs fastened in the ridge part. They almost never give a thrust on the walls.

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

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

Strengthening the ridge assembly for heavy roofing material or with significant snow loads

All of the above gable roof schemes are stable in the presence of uniform loads. But in practice, this almost never happens. There are two ways to prevent the roof from sliding in the direction of greater load: by installing a brace at a height of about 2 meters or by struts.

Options for truss systems with contractions

The installation of contractions increases the reliability of the structure. In order for it to work normally, at the places where it intersects with drains, you need to attach nails to them. The cross section of the beam for the scrum is used the same as for the rafters.

They are attached to the rafter legs with bots or nails. Can be installed on one or both sides. The knot for attaching the bout to the rafters and the ridge run, see the figure below.

In order for the system to be rigid and not “crawl” even under emergency loads, it is enough in this embodiment to provide a rigid fastening of the ridge beam. In the absence of the possibility of its displacement in the horizontal, the roof will withstand even significant loads.

Rafter systems with braces

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

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

Systems with rafter legs. Above is a spacer system, below is a non-spacer system. The nodes of the correct felling for each are located nearby. Below - possible schemes for attaching the strut

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

Bracing systems are necessary if significant uneven shrinkage of the foundation or walls is possible. Walls can sit differently on wooden houses, and foundations on layered or heaving soils. In all these cases, consider the installation of truss systems of this type.

System for houses with two internal load-bearing walls

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

In these systems, a ridge run is not installed: it gives expansion forces. The rafters in the upper part are connected to one another (cut and joined without gaps), the joints are reinforced with steel or wooden plates, which are nailed.

In the upper non-expansion system, the expanding force is neutralized by tightening. Please note that the puff is placed under the run. Then it works efficiently (the top diagram in the figure). Stability can be provided by racks, or jointing - beams installed obliquely. In the spacer system (in the picture it is below), the cross member is a crossbar. It is installed above the run.

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

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

To fasten the racks, nails for 150 mm and bolts 12 mm are used. Dimensions and distances in the figure are in millimeters.

A roof with two slopes is the most common option for completing the box of a private house. In its manufacture, it is important to correctly select the cross-sections of the supporting elements, securely fasten the nodes and choose the right type of construction. The truss system of a gable roof does not have great difficulties and may well be made by hand.

Classification of truss systems according to the method of support

The structure can be classified in two ways. The first of them is the method of supporting the bearing elements. The gable roof truss system of the house in this case includes the following types:

• with layered rafters;
• with hanging rafters.

Types of a gable roof with layered and hanging rafters

Roofing with the use of layered rafters involves their support at two points. The design in this case avoids the occurrence of a serious spacer. To do the installation yourself, you will need the following basic elements:

• rafter legs;
• Mauerlat;
• crossbar;
• intermediate racks and struts with a large span of load-bearing beams;
• crate and counter-crate;
• overlays persistent bars.

At the top point, the installation provides for leaning on the crossbar. The installation also provides support at the lowest point - Mauerlat. You can assemble such a structure for a house with your own hands only in two cases:

Options for assembling a layered gable roof system

1. A layered system is possible if the distance between the gables is not large. That is, such an installation is suitable for a small house with your own hands. The greatest length of the structure, which allows the construction of a wooden crossbar without additional reinforcements, is 6 m. For large spans, it will be necessary to install metal beams as a crossbar. When using a wooden beam, it will be necessary to provide intermediate racks, which are located on average every 2 meters. This can be avoided only when using glued laminated timber of a sufficiently large cross section as a crossbar. In this case, a free layout of the space becomes impossible - the racks in the middle of the room cannot be removed.
2. The second option, when it is possible to install a layered gable roof system with your own hands, is the presence of a wall in the middle of the house. The device in this case provides that the beam, on which the rafters will rest at the top point, will transfer the load to the inner wall. In this case, the supporting structure should not be confused with the partition. The partition rests on the floors, and installing the wall of the house with your own hands involves resting it directly on the foundations. Such a device is suitable for buildings with sufficient width, where it makes sense to install a wall fence in the middle.

The second option is hanging rafters. They are more complex in calculation, but they allow the installation in the under-roof space of a free-plan house. The design assumes the absence of a supporting wooden or metal bar in the upper part. Installation involves supporting the rafters only at the lowest point. In the upper part, the bearing beams are securely connected to each other. Installing such a system is like a farm. The design works on thrust, so it is important to prevent excessive horizontal load on the walls of the house. You can do this by doing the following:

• the device of a monolithic belt along the edge of the walls;
• it is necessary to make a reliable fastening of the Mauerlat of a gable roof to the wall of the house with your own hands;
• to eliminate the spacer, a contraction is established.

Installation of a hanging truss system

The fight or screed becomes one of the significant elements of the gable roof of the house. It prevents the expansion of the walls under the action of thrust. The following types of fights can be distinguished:

• located at the attic floor level;
• located at the level of the attic ceiling.

It is worth noting that the second option provides less reliability, since the higher the element is mounted, the stronger the rafters have an effect on it. If the fight turns out to be too long, you need to make it stronger with your own hands. For this, additional elements of the gable roof of the house are installed - suspensions. They connect the skate to the middle of the puff, which prevents it from sagging.

The gable roof truss system with hanging rafters allows installation with pre-assembly of trusses on the ground, then raise them to the roof and fix them.

This option is only suitable if you have lifting equipment, since the finished gable roofs of the house will become too large and heavy to lift with your own hands.

Classification by type of slope

The second division can be made depending on how the ramp line is designed. The views here suggest the presence of two options:

Gable roof with broken and straight slopes

1. With straight slopes. The easiest way to do. Allows you to get the job done without any hassle. The disadvantage of this do-it-yourself roofing option is the reduction in attic space.
2. With broken slopes. Such types of roofing are more difficult to perform. It is assumed that there is a line along which the angle of inclination changes. The angle of inclination of the lower part of the slope must be made greater than that of the upper. Thus, it turns out to raise the ceiling of the attic and increase the free space. The installation of the roof is carried out with the installation of an additional crossbar at the fracture site.

These types involve a choice between them, depending on the wishes of the future owner of the building.

The main elements of the roof

The rafter system of the gable final part of the building consists of many elements. Installation should begin with a detailed study of each of them and the choice of their sections.

When installing elements under a metal tile or other coating, it implies the use of a bar with a section of 150x150 or 200x200 mm. It is this size that allows you to most optimally distribute the load. then you need to choose a method of fixing it depends on the material of the walls. There are several options:

The scheme of fastening the Mauerlat to the wall

1. Frame, timber or log walls do not require the installation of a Mauerlat. In the case of a frame building, the top framing of the walls serves as a support for the rafter legs. during the construction of fences from timber or logs, the upper crown becomes the Mauerlat. It is important to correctly fix these elements in the wall structure.
2. When used for the construction of lightweight concrete, additional reinforcement will be required. Lightweight concretes include materials such as foam concrete, cinder concrete, expanded clay concrete. They can collapse if the roof is not supported centrally on them. To evenly distribute the load, a monolithic reinforced concrete belt is poured along the edge of the walls. During work, a special wire, studs or bolts are laid in it, on which the Mauerlat will be fastened.
3. For brick means, it is possible not to provide a reinforced concrete belt. In this case, to connect with the strapping beam, a wire is inserted into the masonry, which is then wrapped around the Mauerlat and twisted. The second option - one row before the walls are cut, wooden blocks impregnated with an antiseptic are brought into the masonry from the outside. Such plugs and Mauerlat are fastened with staples. It is also possible to use studs and bolts, for fixing which will require pouring a monolithic belt.

An important point is waterproofing.

When installing, it is important to provide roofing material, linokrom or waterproofing at the junction of concrete or brick with wood. This is required to prevent the wood from rotting on contact with material of a different moisture content.

After fixing the Mauerlat, rafter legs are installed. Their cross section is selected depending on the pitch of the supporting beams, their span, snow load and type of coating. When installing a frame under a metal tile with a step of 60 cm, it is recommended to follow the following recommendations, depending on the span:

• 3 m - 4x15 cm;
• 4 m - 5=15 cm;
• 5 m - 5x17.5 cm;
• 6 m - 5x20 cm.

Table of average values ​​of rafter legs

These are average values, in order to perform a more accurate calculation, it is better to contact a specialist or study additional literature.

There are two ways to fasten the rafter legs to the Mauerlat:

• with a notch;
• without her.

Fastening rafter legs to the Mauerlat with and without a notch

In the first case, they wash down on the strapping beam, in the second, a special plank is nailed to the rafters, which becomes a persistent bar. Further, for both methods, the work is performed in the same way. With the help of metal corners, the inclined beam is fixed so that it does not move relative to the design position along the Mauerlat. Additionally, nails are driven in at an angle.

Scheme of fastening rafters with wire and brackets

In addition, you will need to fasten the rafter to the wall. The implementation of this measure is provided for in the regulatory documents. You can do this in two ways:

• on brackets (suitable for wooden buildings);
• using wire twisting (a more time-consuming option, but the only one possible for stone houses).

You can perform fastening according to the norms through one leg. This is necessary for a more secure attachment of the roof to the box of the house.

If you do the work correctly, you can not worry about its condition even in the strongest winds.

Racks, ties, struts

Such elements are most often made of boards. The optimal thickness is in the range of 32-50 mm. Racks are an exception. Here you can use boards with a thickness of 50-100 mm. Fastening is carried out on studs or using support bars.

Gable roof truss system: design and nodes

A gable roof is the most common in construction. For proper installation, it is recommended to study the device of the gable roof truss system.

The device of the truss system of a gable roof

The gable roof truss system is designed for roofing in the form of two rectangles located at a certain angle to each other in the upper part of the structure. This design is quite often used in the construction of private low-rise buildings, various buildings for domestic and household purposes. At industrial and commercial enterprises, a gable roof is installed on buildings for various purposes, which have a significant length several times greater than the width. The design contains two slopes of different lengths. On the front side, a short slope with a large angle of inclination is installed, on the back - a long one, with a smaller angle of inclination. This configuration allows the main part of atmospheric precipitation to be directed to the non-working zone of the enterprise territory.

Figure 1. Scheme of fillies.

The construction of a gable roof is one of the low-cost options that does not require significant physical effort.

It is performed relatively simply with little experience working with wood material.

Typical bearing elements of the system, specific terms

Figure 2. Scheme of the crate.

In the manufacture of details of the gable roof truss system, softwood lumber is used. Hardwood is undesirable due to its high specific gravity. Most of the elements have specific names that are understood mainly by specialists:

1. Lezhen - timber with a section of 150x150 mm, 180x180 mm. It is laid on the surface of the internal load-bearing wall. Designed for leveling the surface and distributing loads from racks.
2. The rafter leg, or rafter, is a piece of timber or thick board. The main element of the triangular roof structure, bearing the main load from snow, rain, wind and other atmospheric phenomena. The distance between the rafter legs can be from 0.6 to 1.2 m. The step size mainly depends on the plumb line of the roofing material, in some cases, the characteristics of the roofing material should be taken into account.
3. Mauerlat - a square beam with a side size of 150-180 cm. It is laid on the surface of external load-bearing walls. When installing, it must be fixed with anchor bolts or in another reliable way. Distributes the load from the rafter legs to the load-bearing walls.

All parts of a gable roof are interconnected in various ways. Previously, structures were assembled mainly using staples, nails, threaded studs. Now manufacturers of building materials offer a wide range of different brackets for assembling roofs of any configuration. Most parts are fastened with self-tapping screws of the required diameter and length, reinforced with special spikes in the brackets.

Additional elements of the rafter system

Figure 3. Scheme of an arch with three hinges.

In addition to load-bearing parts, additional reinforcing elements are used in the structures:

1. Filly (Fig. 1) - used to increase the length of the rafter legs. Are established in the lower part for the device of cornice overhang. The thickness of the filly is somewhat less than the size of the rafters.
2. Roof overhang, or cornice overhang, is a roof element protruding from the edge of the wall by about 40-50 cm. Designed to protect walls from atmospheric precipitation.
3. The ridge is an element that connects all the rafter legs of the system in the upper part. Installed in a horizontal position.
4. Sheathing (Fig. 2) - boards or bars installed for fixing the roof. They are located perpendicular to the rafter legs, additionally performing the function of their fastening. They take the main effort from the roofing material, distribute it to the rafters. For the device, it is desirable to use edged lumber. With limited funds, you can use unedged, clearing it of bark. If the roof is made of soft material, the crate is made solid. This option can be made from boards or plywood treated with protective materials from high humidity. When corrugated board is used, the crate is performed with a certain step, depending on the weight of the material and its design features.
5. Struts - elements made of timber or thick boards that reinforce the main structure. Distribute the force from the rafter legs to the bearing parts. The assembled structure of struts and puffs was called a farm - an enlarged part with the necessary margin of safety.
6. Racks - are made from pieces of lumber of rectangular or square section. Are established in vertical position under a descent of slopes. The load from the corner connection of the roof rafters is distributed through the posts to the internal load-bearing wall.
7. Puff - a bar or board that fastens the rafters in a hanging system. Creates a rigid triangle shape between rafter legs, compensating for sprawl.

For the manufacture of additional parts, you can use lumber with a section similar to that of load-bearing parts. In order to save money, you can calculate and purchase products of a smaller section.

Two typical ways to arrange truss systems

Figure 4. Scheme of connecting the lower ends of the parts.

The gable roof truss system can be arranged in two main ways:

• hanging rafter system;
• layered system.

The hanging system is used for buildings with a distance between the outer walls of less than 10 m, without an internal load-bearing wall in the middle of the building. In a different configuration of the building, a layered rafter structure is used.

If the building has columns located along one of the central axes, it is possible to use a combined option. Rafter legs located above the columns are mounted with emphasis on the surface of the columns, hanging rafters are installed between them.

Hanging truss system

In structures of this type, the installation of truss beams is carried out on the surface of the outer walls. The disadvantage of this method is the occurrence of force, bursting the walls. To compensate for the load, the beams are pulled together by tightening. The design takes the form of a rigid triangle that retains its shape under the influence of loads. In some cases, floor beams can play the role of puffs. Such a scheme is used when arranging an attic in the attic space.

Hanging rafters can be made in various versions:

Scheme of the reinforced structure.

1. A simple version of the arch with three hinges (Fig. 3) - the design is a rigid triangle, the two sides of which are the rafter legs. The main load creates a bending force on the parts. The force on the third side is aimed at stretching the structure, so instead of a wooden part, a steel tie can be used. The connection of the lower ends of the parts can be assembled in various ways (Fig. 4), by inserting beams into a puff, using wooden elements or metal brackets.
2. Reinforced structure (Fig. 5) - a gable truss system used for roofing of large industrial buildings with a distance between walls of more than 6 m. This system is not suitable for use in small residential buildings. A design feature is the distribution of the puff weight on the skate. Since it is almost impossible to find solid lumber of the required length (6 m or more), the puff is made from segments. The connection of all elements is carried out by a straight or oblique inset. The central part is called the headstock. The connection of the headstock with a tightening is performed by a collet twist with the possibility of adjusting the tension.
3. The device of an arch with a tightening in the upper part of the rafters (Fig. 6) is used for equipment in the attic space of the attic. At the same time, the tensile force in the rafter beams increases. The lower ends of the beams are attached to the Mauerlat bars. The fastening should limit the movement of the beams to the sides along the beam, but allow sliding across. This ensures uniform load distribution and stability of the entire system. Rafter beams should form an overhang.

Many variants of hanging-type systems have been developed. Most are used for relatively small buildings without load-bearing structures inside buildings. For larger buildings, a layered rafter system should be used.

Layered truss system

The main difference of this system is the installation of a vertical beam resting on an internal load-bearing wall located in the middle of the building. This design is necessary when a gable roof is installed on a building with a wall spacing of more than 10 m.

Figure 6. Arrangement of an arch with a puff at the top of the rafters.

1. A properly executed system of non-expanding rafter beams allows you to get rid of the forces that burst the walls. The surface of the slopes is subjected only to the bending force. There are 3 main options for the device of such systems. With all options, the lower ends of the rafters are attached according to the sliding support method. For insurance, an additional mount is installed between the support bar and the rafter leg.
2. You can use a steel strip, wire tie. The options differ in the method of connecting the upper ends of the rafters, docking with the ridge beam. One of the options involves laying rafters on a beam in the form of a sliding support with a cutout device. Mounting can be done using brackets or special brackets. The gable roof, arranged according to the following option, is the most popular because of the simplicity of the device. The top of the rafters can be made end-to-end or overlay with cutting grooves. The corner must be fastened in any of the available ways and fixed on the ridge beam. The third option involves a rigid connection of the run and rafters. For mounting on rafter legs, pieces of boards are stuffed on two sides. A large bending force is formed on the beam, but the load on the rafter beams is reduced.
3. A gable roof for a building with dimensions up to 14 m must have a reinforced truss system. One of the options for increasing strength is the installation of a strut. The part takes on the load from the rafter leg, experiencing a compressive force. To correctly select the installation position of the element, you need to measure the angle of 45-53 ° from the horizontal plane of the building. An additional support device turns an ordinary beam into a reinforced version, consisting of two spans. To install the struts, calculations are not required, you just need to fix it under the rafter, cutting out the joint angle with maximum accuracy.

The technology for installing gable roofs is simple, you can do everything yourself. Work must begin with the installation and fastening of the base to the walls, then mount the gables. It is desirable to carry out work on the manufacture of rafter beams and enlargement of structures on the ground, to lift the assembled elements, install them on the building, and fix them with temporary fasteners. After assembling and installing all the elements, you should fix the crate and proceed with the installation of the roof.

Gable roof truss system: installation and diagrams

The gable roof truss system is designed for roofing in the form of two rectangles located at a certain angle to each other in the upper part of the structure.

Do-it-yourself gable roof truss system: an overview of hanging and layered structures

Rafters perform a number of significant roofing functions. They set the configuration of the future roof, perceive atmospheric loads, and hold the material. Among the rafter duties are the formation of even planes for laying the coating and providing space for the components of the roofing pie. In order for such a valuable part of the roof to flawlessly cope with the listed tasks, information about the rules and principles of its construction is needed. The information is useful both for those who are building a gable roof truss system with their own hands, and for those who decide to resort to the services of a hired team of builders.

Rafter structures for gable roofs

In the device of the truss frame for pitched roofs, wooden and metal beams are used. The starting material for the first option is a board, log, timber. The second is constructed from rolled metal: a channel, a profile pipe, an I-beam, a corner. There are combined structures with steel most loaded parts and wood elements in less critical areas.

In addition to the "iron" strength, the metal has a lot of disadvantages. These include heat engineering qualities that do not satisfy the owners of residential buildings. Disappointing need for the use of welded joints. Most often, industrial buildings are equipped with steel rafters, less often private change houses assembled from metal modules.

In the case of self-construction of truss structures for private houses, wood is a priority. It is easy to work with it, it is lighter, “warmer”, more attractive in terms of environmental criteria. In addition, nodal connections do not require a welding machine and welder skills.

Rafters - a fundamental element

The main "player" of the frame for the construction of the roof is the rafter, among the roofers called the rafter leg. Beds, braces, headstocks, girders, puffs, even Mauerlat may or may not be used depending on the architectural complexity and dimensions of the roof.

The rafters used in the construction of the gable roof frame are divided into:

• Layered rafter legs, both heels of which have reliable structural supports under them. The lower edge of the layered rafter rests on the Mauerlat or on the ceiling crown of the log house. The support for the upper edge can be a mirror analogue of the adjacent rafter or a run, which is a beam horizontally laid under the ridge. In the first case, the truss system is called spacer, in the second, non-spacer.
• hanging rafters, the top of which rests against each other, and the bottom is based on an additional beam - puff. The latter connects the two lower heels of adjacent rafter legs, resulting in a triangular module called a truss truss. The tightening dampens the tensile processes, so that only a vertically directed load acts on the walls. The design with hanging rafters, although it is spacer, does not transfer the spacer itself to the walls.

In accordance with the technological specifics of the rafter legs, the structures constructed from them are divided into layered and hanging. For structural stability, they are equipped with struts and additional racks. For the arrangement of supports for the top of the layered rafters, beds and girders are mounted. In reality, the truss structure is much more complicated than the elementary patterns described.

Note that the formation of a gable roof frame can generally be carried out without a truss structure. In such situations, the alleged planes of the slopes are formed by slegs - beams laid directly on the bearing gables. However, we are now specifically interested in the device of the gable roof truss system, and it can involve either hanging or layered rafters, or a combination of both types.

Subtleties of fastening rafter legs

The truss system is fastened to brick, foam concrete, aerated concrete walls through the mauerlat, which in turn is fixed with anchors. Between the Mauerlat, which is a wooden frame, and the walls of these materials, a waterproofing layer of roofing material, waterproofing, etc. is necessarily laid.

The top of the brick walls is sometimes specially laid out so that something like a low parapet is obtained along the outer perimeter. So it is necessary that the Mauerlat placed inside the parapet and the walls do not burst the rafter legs.

The rafters of the frame of the roofs of wooden houses rest on the upper crown or on the ceiling beams. The connection in all cases is made by cutting and duplicated with nails, bolts, metal or wooden plates.

How to do without furious calculations?

It is highly desirable that the cross section and linear dimensions of the wooden beams be determined by the project. The designer will give clear calculation justifications for the geometric parameters of the board or beam, taking into account the entire range of loads and weather conditions. If there is no home design development master at his disposal, his path lies on the construction site of a house with a similar roof structure.

You can ignore the number of storeys of the building under construction. It is easier and more correct to find out the required dimensions from the foreman than to find them out from the owners of a shaky unauthorized construction. After all, the foreman is in the hands of documentation with a clear calculation of the loads per 1 m² of roof in a particular region.

The installation step of the rafters determines the type and weight of the roofing. The heavier it is, the smaller the distance between the rafter legs should be. For laying clay tiles, for example, the optimal distance between the rafters will be 0.6-0.7 m, and for the installation of metal tiles and profiled sheets, 1.5-2.0 m is acceptable. However, even if the step required for the correct installation of the roof is exceeded, there is a way out . This is a reinforcing counter-lattice device. True, it will increase both the weight of the roof and the construction budget. Therefore, it is better to deal with the step of the rafters before the construction of the rafter system.

Craftsmen calculate the pitch of the rafters according to the design features of the building, tritely dividing the length of the ramp into equal distances. For insulated roofs, the step between the rafters is selected based on the width of the thermal insulation boards.

Rafter structures of layered type

Rafter structures of the layered type are much simpler in execution than their hanging counterparts. A justified plus of the layered scheme is to provide full ventilation, which is directly related to the longevity of the service.

Distinctive design features:

• Mandatory presence of support under the ridge heel of the rafter leg. The role of the support can be played by a run - a wooden beam resting on racks or on the inner wall of the building, or the upper end of an adjacent rafter.
• The use of Mauerlat for the construction of a truss structure on walls made of brick or artificial stone.
• The use of additional runs and racks where the rafter legs, due to the large size of the roof, require additional support points.

The minus of the scheme is the presence of structural elements that affect the layout of the internal space of the operated attic. If the attic is cold and the organization of useful premises is not supposed to be in it, then the layered construction of the truss system for the installation of a gable roof should be preferred.

A typical sequence of work on the construction of a layered truss structure:

• First of all, we measure the height of the building, the diagonals and the horizontalness of the upper cut of the skeleton. When identifying vertical deviations of brick and concrete walls, we eliminate them with a cement-sand screed. Exceeding the heights of the log house we squeeze. By placing chips under the Mauerlat, vertical flaws can be dealt with if their magnitude is insignificant.
• The floor surface for laying the bed must also be leveled. He, the Mauerlat and the run must be clearly horizontal, but the location of the listed elements in the same plane is not necessary.
• We process all wooden parts of the structure before installation with fire retardants and antiseptic preparations.
• We lay waterproofing on concrete and brick walls for the installation of a Mauerlat.
• We lay the Mauerlat beam on the walls, measure its diagonals. If necessary, we slightly move the bars and turn the corners, trying to achieve the perfect geometry. Align the frame horizontally if necessary.
• We mount the Mauerlat frame. The splicing of the beams into a single frame is carried out by means of oblique cuts, the joints are duplicated with bolts.
• We fix the position of the Mauerlat. Fasteners are made either with brackets to wooden plugs laid in the wall ahead of time, or with anchor bolts.
• We mark the position of the bed. Its axis should recede from the Mauerlat bars at equal distances on each side. If the run will be based only on racks without lying down, the marking procedure is carried out only for these columns.
• We install the bed on a two-layer waterproofing. We fasten it to the base with anchor bolts, connect it to the inner wall with wire twists or staples.
• We mark the installation points of the rafter legs.
• We cut out racks according to uniform sizes, because our bed is set to the horizon. The height of the racks must take into account the dimensions of the section of the run and the bed.
• Installing racks. If provided by the project, we fix them with spacers.
• We lay the run on the racks. We check the geometry again, then install the brackets, metal plates, wooden mounting plates.
• We install a trial rafter board, mark the places of trimming on it. If the Mauerlat is set strictly to the horizon, there is no need to adjust the roof rafters in fact. The first board can be used as a template for making the rest.
• We mark the installation points of the rafters. Folk craftsmen for marking usually prepare a pair of slats, the length of which is equal to the gap between the rafters.
• According to the markup, we install the rafter legs and fasten them first at the bottom to the Mauerlat, then at the top to the run to each other. Every second rafter is screwed to the Mauerlat with a wire bundle. In wooden houses, the rafters are screwed to the second crown from the top row.

If the rafter system is done flawlessly, the layered boards are mounted in random order. If there is no confidence in the ideal structure, then the extreme pairs of rafters are installed first. A control twine or fishing line is stretched between them, according to which the position of the newly installed rafters is adjusted.

The installation of the truss structure is completed by installing the filly, if the length of the rafter legs does not allow the formation of an overhang of the required length. By the way, for wooden buildings, the overhang should “go beyond” the contour of the building by 50 cm. If the organization of the visor is planned, separate mini-rafters are installed under it.

Hanging truss systems

The hanging type of truss systems is a triangle. The two upper sides of the triangle are folded by a pair of rafters, and the puff connecting the lower heels serves as the base. The use of tightening allows you to neutralize the effect of the spread, therefore, only the weight of the crate, the roof, plus, depending on the season, the weight of precipitation, acts on walls with hanging truss structures.

The specifics of hanging truss systems

Characteristic features of hanging type truss structures:

• Mandatory presence of a puff, made most often of wood, less often of metal.
• The ability to refuse the use of Mauerlat. A frame made of timber will be successfully replaced by a board laid on a two-layer waterproofing.
• Installation on the walls of ready-made closed triangles - roof trusses.

The advantages of the hanging scheme include the space under the roof free from racks, which allows you to organize an attic without pillars and partitions. There are disadvantages. The first of these is the limitation on the steepness of the slopes: their slope angle can be at least 1/6 of the span of a triangular truss, steeper roofs are strongly recommended. The second disadvantage is the need for thorough calculations for the competent device of cornice nodes.

Among other things, the angle of the truss truss will have to be set with jewelry accuracy, because. the axes of the connected components of the hanging rafter system must intersect at a point, the projection of which must fall on the central axis of the Mauerlat or the lining board replacing it.

Subtleties of long-span hanging systems

Puff - the longest element of the hanging rafter structure. Over time, it, as is typical of all lumber, deforms and sags under the influence of its own weight. Owners of houses with spans of 3-5m are not too concerned about this circumstance, but owners of buildings with spans of 6 meters or more should think about installing additional parts that exclude geometric changes in tightening.

To prevent sagging in the installation scheme of the truss system for a large-span gable roof, there is a very significant component. This is a pendant called a grandmother. Most often, it is a bar attached with wooden surfs to the top of the truss truss. You should not confuse the headstock with the racks, because. its lower part should not come into contact with the puff at all. And the installation of racks as supports in hanging systems is not used.

The bottom line is that the headstock, as it were, hangs on a ridge knot, and a tightening is already attached to it with the help of bolts or nailed wooden plates. Threaded or collet type clamps are used to correct slack.

Adjustment of the tightening position can be arranged in the zone of the ridge knot, and the headstock can be rigidly connected to it with a notch. Instead of a bar in non-residential attics, reinforcement can be used to manufacture the described tightening element. It is also recommended to arrange a headstock or suspension where the puff is assembled from two bars to support the connection area.

In an improved hanging system of this type, the headstock is complemented by strut beams. The stress forces in the resulting rhombus are extinguished spontaneously due to the competent arrangement of the vector loads acting on the system. As a result, the truss system pleases with stability with a slight and not too expensive upgrade.

Hanging type for attics

In order to increase the usable space, the tightening of the rafter triangles for the attic is moved closer to the ridge. A perfectly reasonable move has additional advantages: it allows you to use puffs as the basis for filing the ceiling. It is attached to the rafters by cutting with a semi-frying pan with a duplication of a bolt. It is protected from sagging by installing a short headstock.

A noticeable drawback of the attic hanging structure is the need for accurate calculations. It is too difficult to calculate it on your own, it is better to use a ready-made project.

Which design is more cost effective?

Cost is an important argument for an independent builder. Naturally, the price of construction for both types of truss systems cannot be the same, because:

• In the construction of a layered structure for the manufacture of rafter legs, a board or beam of small section is used. Because layered rafters have two reliable supports under them, the requirements for their power are lower than in the hanging version.
• In the construction of a hanging structure, the rafters are made of thick timber. For the manufacture of puffs, a material similar in cross section is required. Even taking into account the rejection of the Mauerlat, the consumption will be significantly higher.

Saving on the grade of material will not work. For the bearing elements of both systems: rafters, purlins, beds, Mauerlat, attendants, racks, lumber of the 2nd grade is needed. For crossbars and puffs working in tension, you will need the 1st grade. In the manufacture of less responsible wooden slips, the 3rd grade can be used. Without counting, we can say that in the construction of hanging systems, expensive material is used to a greater extent.

Hanging trusses are assembled in an open area next to the object, then transported assembled upstairs. To lift weighty triangular arches from a bar, you will need equipment, for which you will have to pay rent. And the project for complex nodes of the hanging version is also worth something.

There are actually many more methods for constructing truss systems for roofs with two slopes. We have described only the basic varieties that are actually applicable for small country houses and buildings without architectural ideas. However, the information provided is sufficient to cope with the construction of a simple truss structure.

Do-it-yourself gable roof truss system: device, design, installation

In order for the truss system of a gable roof to be built competently and firmly with your own hands, you need information about the rules and principles of the device, fastening and

Construction of houses

When building one-story houses, a roof with two slopes is very popular. This is due to the speed of construction of the structure. In this parameter, only a single-pitched roof can compete with a gable roof. In the device, a gable rafter roof is not too complicated. And you will successfully master this work on your own.

The design of the gable roof truss system

The gable roof consists of two inclined surfaces that have a rectangular shape. Thanks to this, precipitation, which is represented by rain and melt water, flows off the roof in a natural way. The gable roof has a rather complex structure. It consists of such structural units: Mauerlat, rafter system, filly, ridge, roof overhang, bed, struts, puffs, crate and racks:

1. Mauerlat. This element performs the functions of transferring and distributing the load created by the rafter system on the load-bearing walls of the house. For the manufacture of Mauerlat, a beam is used, which has a square section - from 100 by 100 to 150 by 150 mm. It is better to use softwood. The beam is placed around the perimeter of the building and fixed to the outer walls. For fastening use special rods or anchors.
2. Rafter leg. Rafters form the main frame of any roof. In the case of a gable roof, they form a triangle. The rafters are responsible for the uniform transfer of loads to the Mauerlat. First of all, those that arise from precipitation, wind and the weight of the roof itself. For the manufacture of rafters, boards are used that have a section of 100 by 150 or 50 by 150 mm. Choose a rafter pitch of about 60-120 cm, depending on the type of roofing material. When using a heavy coating, place the rafter legs more often.
3. Skate. This element connects two slopes at the top of the roof. The ridge is formed after connecting all the rafter legs.
4. Filly. They act as a continuation of the rafters and form the overhang of the gable roof. It is customary to install fillies if the rafter legs are very short and do not allow an overhang to form. To make this structural unit, take a board that has a smaller section than the rafter. The use of fillies facilitates the construction of the truss system, as it allows the use of short rafters.
5. Eaves. This part of the design of the gable roof truss system is responsible for draining water from the walls during rain and at the same time preventing them from getting wet and quickly destroyed. The overhang protrudes from the wall, as a rule, by 400 mm.
6. Sill. It is located on the inner wall and serves to evenly distribute the load from the roof racks. For the manufacture of bedding, a beam is used, which has a section of 150 by 150 or 100 by 100 mm.
7. Racks. These vertical elements are responsible for transferring the load from the ridge to the interior walls. To create this element, prepare a beam that has a square section of 150 by 150 or 100 by 100 mm.
8. Struts. They are needed to transfer loads from the rafters to the load-bearing walls. Struts and puffs form a solid structure called a truss. Such a device is designed to withstand loads at large spans.
9. Puff. This structural unit, together with the rafters, forms a triangle. It does not allow the rafters to part in different directions.
10. Crate. This design consists of boards and bars. They are attached perpendicular to the rafters. Sheathing is necessary to evenly distribute the weight of the roof covering and the loads created by weather phenomena on the rafters. In addition, the crate is required to fasten the rafters together. When arranging a soft roof to create a crate, you should not use boards and bars, but moisture-resistant plywood.

Varieties of gable roof truss system

There are gable truss systems with hanging and layered rafters. Ideally, the design contains a combination of them. It is customary to install hanging-type rafters if the outer walls are located at a distance of less than 10 m. Also, there should no longer be walls between them that divide the space of a residential building. The design with hanging rafters creates a bursting force transmitted to the walls. It can be reduced if you arrange a puff made of wood or metal and place it at the base of the rafters.

At the same time, the rafters and tightening form a rigid geometric figure - a triangle. It is not able to deform under loads that are in any direction. The puff will be stronger and more powerful if it is placed higher. The floor beams act as puffs. Thanks to their use, the hanging truss system of a gable roof acts as the basis for the arrangement of the attic floor.

Laminated rafters in their design have a support beam, which is located in the middle. It is responsible for transferring the weight of the entire roof to the intermediate column or middle wall located between the outer walls. It is recommended to install rafters if the outer walls are placed more than 10 m apart. If there are columns instead of internal walls, you can alternate between rafters and hanging rafters.

Do-it-yourself gable truss system

The roof must be strong to withstand various loads - precipitation, gusts of wind, the weight of a person and the roofing itself, but at the same time light, so as not to put a lot of pressure on the walls of the house. A properly arranged gable rafter roof evenly distributes the load on all load-bearing walls.

Calculation of a gable roof

The choice of slope of a gable roof will depend on the material you have chosen for laying on the roof and architectural requirements:

• When building a gable roof, remember that it must slope at an angle of more than 5 degrees. It happens that the slope of the roof reaches 90 °.
• For areas with heavy rainfall, and when the roofing does not fit snugly, steep slopes are made. In this situation, the angle should be 35-40 ° so that precipitation does not linger on the roof. But such an angle does not allow building a living space in the attic. The output will be a broken roof structure. It will have a flat upper part, and on the lower part there will be a sharp slope.
• In regions with strong gusts of wind, sloping roofs are equipped. If constant winds prevail in the area, then make a slope of 15-20 ° for high-quality protection of the roofing.
• It is best to choose the middle option. Equip a gable roof that is not too steep. But also the slope should not be very gentle.
• When choosing a large angle of the roof, its windage increases, and, accordingly, the price of the gable roof truss system and the crate. After all, such a slope entails an increase in the area of ​​\u200b\u200bthe roof and, accordingly, the amount of necessary material - building and roofing.

When buying materials for the construction of a gable roof, it is useful to calculate its area:

1. Find the area of ​​one slope of the structure, and then double the result.
2. Ideally, a slope is an inclined rectangle that is placed along a long load-bearing wall. To determine the area of ​​​​a slope, multiply its length by its width.
3. The length of the slope is equal to the length of the wall. In addition, the length of the ledge of the roof above the gable is added to the length. Remember that the protrusions are present on both sides.
4. The width of the slope is the length of the rafter leg. To it is added the length of the ledge of the roof above the load-bearing wall.

In order to properly design the structure, it is recommended to carry out an accurate calculation of the gable roof truss system, including determining the loads and characteristics of the rafters:

1. When erecting a roof for a standard building that has one floor, the design load on the roof will consist of two values. The first of them is the weight of the roof, the second is the load from external factors: precipitation and wind.
2. Calculate the weight of the roof by adding up the weight of each layer of the "pie" - heat-insulating, vapor barrier and waterproofing materials, truss system, battens and directly roofing material. Calculate the weight per 1 m2.
3. Increase the result by 10%. You can also take into account the correction factor. In our case, K=1.1.
4. If you plan to change the design of the roof over time and increase the angle of its inclination, then include a margin of safety in the calculation. Take immediately higher load indicators than those that you received at the time of the calculation. It is recommended to build on the value, which is 50 kg per 1 m2.
5. When calculating the load exerted by atmospheric phenomena, take into account the climatic features of the area where the building is located. In this calculation, take into account the slope of the slope. If the gable roof forms an angle of 25 degrees, then take the snow load equal to 1.
6. If the roof is equipped with a greater slope - up to 60 degrees, the correction factor reaches 1.25. Snow load for an angle greater than 60 degrees is not taken into account.
7. The rafters transfer the entire load from the created structure to the load-bearing walls. Therefore, their parameters must also be taken appropriately. Select the section and length of the rafter leg, depending on the current load on the roof and the angle of the slope. Increase the values ​​obtained by 50% to ensure a high margin of safety.

Mauerlat installation methods

The construction of any roof begins with the installation of a Mauerlat:

• If logs or timber were used to build the walls, then the upper timber will act as a Mauerlat, as shown in the photo of the gable roof truss system.
• If you used bricks to build walls, then brick the metal rods into the masonry. They must have a cut thread for attaching the Mauerlat. Install rods every 1-1.5 m. Choose rods with a diameter of at least 10 mm. Lay waterproofing between masonry and Mauerlat.
• For walls made of ceramic or foam concrete blocks, pour concrete on top. Be sure to make the layer reinforced. It should have a height of approximately 200-300 mm. Be sure to attach metal rods that are threaded to the reinforcement.
• For Mauerlat, use a beam that has a section of 15 by 15 cm. It will act as a kind of foundation for the truss system.
• Lay the Mauerlat on the top edge of the wall. Depending on its design, the Mauerlat can be laid along the outer and inner edges. Do not place it close to the very edge, as otherwise it may be torn off by the wind.
• Mauerlat is recommended to be placed on top of the waterproofing layer. To connect all the parts into one whole, use bolts and metal plates.
• To avoid sagging, make a lattice of racks, struts and a crossbar. To do this, take boards measuring 25x150 mm. The angle between the strut and the leg of the rafter should be as straight as possible.
• If using a rafter leg that is too long, install another support. She must lean on the bed. Each element is associated with two adjacent ones. As a result, a stable structure is created around the entire perimeter of the roof.

Rafter leg attachment

The best option for a gable roof truss system is a combination of sloping and hanging rafters. This design allows you to create a reliable gable roof and reduce the cost of building materials. Consider the following recommendations when working:

1. Use only the highest quality wood as a material. Beams that have cracks and knots should not be used.
2. Rafters have standard dimensions - 50x150x6000 mm. When the beams are longer than 6 m, it is recommended to increase the width of the board so that the beams do not break under their own weight. Take boards 180 mm wide.
3. First, make a template for the rafter leg. Attach the board to the floor beam and the end of the ridge beam. Having outlined two lines, saw off a board along them. The template is ready.
4. Cut the rafters according to this pattern. After that, do the top washed down on them.
5. Take the resulting workpiece, bring it to the floor beam to mark the lower cut in place.
6. Install all rafters. At the same time, remember that after installing one leg, you must immediately install the opposite one. So you will quickly remove the lateral loads on the ridge beam.
7. If the slope is too long, then standard boards will not be enough to make a rafter leg. In this case, you can splice two boards together. To do this, sew on them a piece of wood of a similar section. It should have a length of 1.5 - 2 meters. According to the diagram of the gable roof truss system, the joint should always be at the bottom. Under it, install an additional rack.
8. Attach the rafter leg to the ridge beam with nails. Use self-tapping screws to fasten the rafters to the floor beam. Metal mounting plates are also suitable. In addition, a few nails are added.
9. If you are building a structure exclusively from hanging rafters, then skip the next step. When erecting a structure with layered rafters, you need to think about the supports that are installed on their floor. To reduce the deflection of the rafters, correctly calculate the location of such supports.
10. If you're building a gabled mansard roof, the intermediate studs will form the frame for the side walls.
11. When performing this work, maintain a certain step of the beams. Set its size at the design stage.
12. After installing the rafters, attach the ridge. It is located on their upper edge. For fastening use metal corners or staples. Bolts are the most popular.

Giving structure rigidity

After installing the gable roof truss system, strengthen it using the technology below:

• For smaller buildings, such as saunas, cottages, utility buildings, and roofs with a simple hanging rafter system, connect each pair of rafters from below with a tightening and from above using a crossbar.
• For large buildings that are light at the same time, provide a lightweight roof. The walls must support it.
• If the house has a width of 6-8 m, then the structure should be tightened. Install in the middle of the support. Such racks are called grandmas. Place them at each pair of rafter legs.
• If the span of the walls reaches 10 meters, then reinforcing beams will be needed. The struts act as an additional support for the rafter legs for tightening. They are attached to each rafter - closer to the ridge or in the middle of the rafter leg. Fasten them to the bottom end of the headstock and to each other as shown in the gable roof truss video.
• In a situation with long roofs, gable beams should be relieved. This is done by installing braces. The upper end should rest against the corner of the gable. The lower one is mounted on the central floor beam. For fasteners, use a beam that has a large cross section. So you can prevent them from breaking if there are strong gusts of wind.
• In areas where winds predominate, the rafters must be resistant to such influences. Strengthen them by installing diagonal ties. Boards are nailed from the bottom of one rafter to the middle of the next.
• For greater rigidity, when creating the most critical fasteners, it is better not to use nails. Use pads and metal fasteners for this. Nails will not be able to provide high-quality fastening, since the wood can dry out after some time.

Lathing of the truss system

The final stage of the construction of the gable roof truss system is the creation of the crate. It is on it that you will lay the roofing. Carry out the work in the following sequence:

1. Select a dry timber for the crate. It should not have cracks or knots. Nail the bars on the bottom. Attach two boards near the ridge so that there are no gaps. The lathing must withstand the weight of the top roofing material and not sag under the weight of the workers.
2. If you will equip a soft roof, make two layers of sheathing. One is sparse, the other is solid. The same applies to roll roofing. To begin with, parallel to the ridge beam, place boards that are 25 mm thick and no more than 140 mm wide. A small gap is allowed - no more than 1 cm. Lay a continuous layer on top. To do this, it is better to use roofing plywood, slats or boards of small thickness. After that, check that there are no errors left on the crate - bumps and knots. Also check that the nail heads are not sticking out.
3. Lay one layer of timber under the metal tile. It should have a section of 50 by 60 mm. Do the same when using slate or steel roofing sheets. Maintain a step between the timber, depending on the roofing you choose - from 10 to 50 cm. Hammer nails closer to the edges of the board, and not in the middle. Drive hats deep. So they will not be able to damage the roof later. If you are making a crate for a metal tile, then remember that the connection of the timber at the same level should fall on the rafters.

When you have installed and strengthened the gable roof truss system, you can start installing the roofing pie. Place a thermal insulation material between the rafters, a layer of vapor barrier and waterproofing. When using insulation in slabs, calculate in advance the pitch of the rafters for its installation. At the final stage, fasten the roofing material.

The device of the gable roof truss system, Building Portal

Construction of houses In the construction of one-story houses, a roof with two slopes is very popular. This is due to the speed of construction of the structure. For this setting,

The truss system of any object is equivalent to the value of the load-bearing structural elements of the house. The roof plays the role of a node under which the stiffening ribs of the building are assembled. Accordingly, when installing the roof with your own hands, it is required to give the maximum value to all structural units, even when using a simple option - gable.

Advantages of gable roofs

There are a lot of options for pitched truss systems. Among them, simple symmetrical is especially popular. Why? Here are her virtues:

• On the basis of a gable roof, variations are created to reflect the special architecture of the building.
• Simple calculations, easy to understand.
• The one-piece design creates favorable conditions for the dryness of the internal space and the unhindered flow of water, snow and ice.
• The maintainability, strength and durability of a gable roof are much higher than other options.

Depending on the size, homeowners always have the opportunity to equip the under-roof space, make it a full-fledged floor or attic. In a word, a gable roof is the right and profitable solution for any object, whether it is a residential building, a summer house or a bathhouse.

Elements of the truss system

Depending on the type of roof, structural elements vary. Without knowledge of the appointments of each, it is impossible to arrange a reliable coverage at home. Let's analyze in detail:

Mauerlat

The basis of the truss system. It is a beam with a section of at least 150 mm, or an I-beam channel, if the roof structure is metal. It is located on the bearing walls of the object. Its purpose is to distribute the load of the system evenly throughout the structure of the house.

Rafter leg

Structural basic unit of the system. Together with others, it forms a truss system - strengthening the strength of the entire roof. It is made of a wooden beam, which is not inferior in cross section to Mauerlat or profile pipes.

Rafter rack

Vertical bar or pipes. Depending on the variant of the gable roof, the pillars can be located in the center and / or on the sides. They take part of the weight of the entire truss system, which is why the cross section is 150 mm.

Rafter girders

Horizontal beams laid on racks and under the ridge to support the rafter legs. They provide structural rigidity and relieve stress on trusses.

Puffs and braces

Connecting beam for rafters. The action is similar - relieving the stress of a beam or metal and making the structure rigid.

lying down

Mounting support for racks and struts. To securely connect these two elements, you need a large cross-section beam - 150 mm or a thick-walled pipe of impressive diameter.

Lathing beam

Elements laid perpendicular to the rafters. Serve to install the selected roofing and create a multilayer protective cake. The cross section is small - 40–50 mm.

If the conceived roof structure is made of wooden beams, you should carefully consider the quality of the wood upon purchase - the beam should not have interspersed knots, be made of soft woods.

Also, wood must have natural moisture, otherwise it will begin to dry right in the system structure, cracking, deforming the roof model, depriving it of reliability and safety.

Calculation of the truss system

A gable roof is a complex structure. The project takes into account many factors - natural nuances, wind, constant and variable loads. It is extremely difficult to make calculations on your own, without special knowledge about the climate of the area, the characteristics of the material for the manufacture of the system, and the nuances of pressure distribution.

Ideally, the calculations are at the mercy of professionals, you can independently choose only the material for coating - the following parameter depends on its type:

Tilt angle

The minimum angle of inclination of the roof relative to the parallel of the earth is 5 degrees. However, its dependence comes from the chosen roofing material. In this capacity, traditional slate, profiled sheet, flexible and metal tiles are used.

They are guided by the following rule: the steeper the slope, the more textured the roof can be.
From 5 degrees for laying rolled protective insulation of the roof. The number of layers matters - up to 15 degrees three-layer coatings, above - two- and single-layer coatings.

• From 6 - ondulin.
• From 11 - slate.
• From 12 - corrugated board.
• From 14 to 20 - metal tiles.
• From 15 to 45 - soft roof.

Thus, the resulting precipitation - snow, water - will not linger on the surface, although complete cleaning requires one's own efforts or the involvement of specialists for the installation of the Anti-Ice system.

Determining the parameters of the rafters - step, length, section

The rarer the step, the more impressive the cross-section of the beam or the diameter of the pipes should be. As a rule, for load-bearing structures, this parameter is at least 150 mm, 100 mm - for country houses and related construction - gazebos, bathhouses, outbuildings.

Next, you need to set the number of rafters per slope: its length is divided by the installation step, which is from 60 to 100 cm + 1 extreme leg. Multiplying the result by 2 gives the total. Depending on the section of the beam, the amount of rafter legs and the installation step vary.

The length of the rafters is simply calculated if the school knowledge about the right triangle is left in the luggage. The rafter leg is equal to the hypotenuse of the resulting figure. The calculation is as follows: A² + B² = C², where - A is the height of the roof, B is half the length of the pediment, C is the length of the rafter leg. To the resulting value is always added from 30 to 70 cm for cornice overhangs.

Types of truss systems

Before getting down to work, it is important to choose a truss system option for a gable roof. There are few of them, each has its own advantages and disadvantages:

hanging

Suitable only for a standard roof width of 6 m, respectively, this is the length of the rafter leg. Fastening occurs by fixing the ends to the ridge run and the bearing wall. Be sure to install a puff that levels the stress and pressure of the structure.

In addition, they will play the role of load-bearing beams. Without them, the structure will disperse under weight. The advantages of the option are in the absolute dryness of the roof surface during the off-season, and in less deformation at the time of shrinkage.

Layered

The option is suitable for any roof width. Reliability and stability is ensured by fixing the bed to the Mauerlat. Thus, the pressure is leveled by the rack, which reduces the tension in the rafter legs. The advantage of the system is simplicity, but the design requires large investments - additional lumber is required to equip the beds.

hybrid

These systems are typical for multi-pitched roofs, where transitions are accompanied by numerous reinforcements, beams, posts, beds, slopes and other elements for the stability of the entire structure. The device is expensive and complicated, so only a professional should deal with the project and construction. At least curate it.

Do-it-yourself installation of a gable roof

So, when the option of the truss system is selected, lumber is purchased, a roof project is drawn up, you can get to work. You cannot deviate from the sequence of steps. This threatens to delay installation and loss of structural reliability.

Mauerlat mount

If the length of the beam for installing the Mauerlat is insufficient, an extension is made. Using the half-tree cutting method, the ends are connected. Additional fasteners are anchor bolts. Do not use self-tapping screws, dowels or nails - they are unreliable. Mounting to the wall is as follows:

• There must be a margin of at least 5 cm from the edge.
• Holes are drilled along the wall for inserting fasteners. Similar actions are carried out with a bar.
• Mauerlat is attached to the edge with steel studs. The fastening step is more often 2 times than the distance between the rafter legs. Subsequently, before installing the main units, they are guided by metal marks.

Important - before laying the Mauerlat, the edge of the wall is protected with waterproofing. Spread one layer even if the house is made of wood.

Making and fixing rafters

Roof trusses are convenient in that they can be assembled on the ground into a finished structure and moved to the roof. This will reduce installation time, however, the model is heavy and lifting equipment will be required, which, of course, will increase the cost of the project.

For budget construction, another method is suitable:

• At the bottom and top of the rafter legs, a gash is made to attach to the Mauerlat and the ridge run. This must be done separately with each unit, after lifting the wood up.
• Places for fixing are marked on the Mauerlat and a ridge run is installed: racks are installed along the gables, on which a beam is placed. If the length is not enough, it is increased, but in a different way, unlike the Mauerlat - a board is screwed to the junction from both sides.
• Depending on the chosen model of the truss system - layered, hanging - they make cuts in the ridge beam, Mauerlat or drill holes in them for fasteners.
• Next, begin the installation of rafter legs from opposite ends of the roof, gradually moving towards the middle. Between the corners of the extreme trusses, it is not bad to stretch the cord to exactly match the entire horizontal part.
• Between themselves, the rafter legs are connected by puffs and struts. Under the ridge part, at the angle formed by the rafters, wooden linings are stuffed, and the ends themselves are tightened with bolts.

More recently, professional builders have begun to use sliding fasteners for roof installation. Metal plates securely hold the bearing elements and at the same time move due to shrinkage. This cancels out its effects.

The work of fixing the rafters is hard and long. You should calculate the time in advance - you can not leave the roof unfinished during the rainy season, otherwise the rigidity of the structure will be lost in the future due to absorbed moisture.

Gables and framing

The side parts of the roof - gables, are made in the form of ready-made shields from boards and are completely installed at the top. Difficulties should not arise - it is only important to carefully file them at the required angle. It is necessary to fasten the crate only after the final appearance of the roofing is known. For example:

• Under the corrugated board, the step of the crate beam will be 440 mm.
• The metal tile is fastened to the crate in increments of 350 mm.
• A soft roof needs a solid plywood coating.

It is important to note the places for the passage of the chimney - the crate should not come into contact with a brick or metal surface. The distance to the hot unit is at least 15 cm. Before installing the lathing, the finished roof is covered with waterproofing with allowances extending beyond the edges of the walls. Then the beam is mounted.

If it is decided to make a warming cake from above, then first the vapor barrier is strengthened from the inside, then the selected material is put into the boxes formed by the rafters. Next, waterproofing and wind protection.

Then it is required to re-mark the contours of the rafter legs with a beam 20 * 20 and then fill a new layer of the crate, along which the roofing material will be laid - the formation of ventilation ducts. This method will save the capacity of the under-roof space if the owners are going to use it for a specific purpose.

Roofing material flooring

Regardless of the type of roofing raw material, installation starts from the edges of the roof and leads it up, laying one unit on top of the other. Thus, rain moisture will not get under the material.

The method of fastening depends on the type of material - soft tiles or tiles with a bitumen or polymer base are fused. Solid profiled sheets - ondulin, metal tiles - are fixed in pre-drilled holes to the crate, using rubber pads to seal and preserve the anti-corrosion layer.

As a result: the description of the installation of the truss system and the roof is easy only on the screen or paper. In reality, the process is complex and multifaceted. Therefore, if knowledge is not enough, it is better to invite professionals to work - their work is always guaranteed.