Knots of residential wooden roofs. Types and diagrams of rafter systems: overview and recommendations for installing a roof rafter system

When designing any residential building, architects Special attention pay attention to the roof, since it performs not one, but several functions at once, depending on its design features. It must be said that not all future homeowners are satisfied with an ordinary gable roof, although it can be called the most reliable, since it has only two pitched planes and one joint between them. Many are attracted to more complex designs, which add special attractiveness and originality to the building. Other, more practical homeowners prefer attic structures, which can simultaneously serve as a roof and a second floor.

The basis of any roof is an individual rafter system, which has its own design features. It will be much easier to choose the right roof frame if you figure out which ones in advance. types and diagrams of rafter systems used in construction practice. After receiving such information, it will become more clear how difficult such structures are to install. This is especially important to know if you plan to build the roof frame yourself.

Main functional tasks of rafter systems

When arranging pitched roof structures, the rafter system serves as a frame for covering and for holding materials “ roofing pie" With proper installation of the frame structure, the necessary conditions will be created for the correct and non-insulated types of roofs that protect the walls and inner space houses from various atmospheric influences.

The roofing structure is also always the final architectural element of the exterior design of the building, supporting it with its appearance stylistic direction. However, the design features of rafter systems must first of all meet the strength and reliability requirements that the roof must meet, and only then the aesthetic criteria.

The frame of the rafter system forms the configuration and angle of inclination of the roof. These parameters largely depend on natural factors, characteristic of a particular region, as well as the desires and capabilities of the homeowner:

• Amount of precipitation in different periods of the year.
• Direction and average speed winds in the area where the building will be erected.
• Plans for the use of space under the roof - arranging residential or non-residential premises in it, or using it only as air gap for thermal insulation of rooms below.
• Type of planned roofing material.
• Financial capabilities of the homeowner.

Atmospheric precipitation and the strength of wind currents place a very sensitive load on the roof structure. For example, in regions with heavy snowfall, you should not choose a rafter system with a small slope angle, since snow masses will linger on their surface, which can lead to deformation of the frame or roofing or to leaks.

If the area where the construction will take place is famous for its winds, then it is better to choose a structure with a slight slope of the slope so that sudden gusts that occur do not tear off individual elements of the roof and roofing.

Main elements of roof structure

Parts and components of rafter systems

Depending on the chosen type of rafter system, the structural elements used can vary significantly, however, there are parts that are present in both simple and complex systems roofs

To the main elements of the rafter system pitched roof relate:

• Rafter legs that form the roof slopes.
• - wooden beam, fixed to the walls of the house and used to fix the lower part of the rafter legs on it.

• A ridge is the junction of the frames of two slopes. It is usually the highest horizontal line roof and serves as a support on which the rafters are fixed. The ridge can be formed by rafters fastened together at a certain angle or fixed on a ridge board (purlin).
• Sheathing is slats or beams mounted on rafters with a certain pitch and serving as the basis for the flooring of the selected roofing material.
• Supporting elements, which include beams, purlins, racks, struts, ties and other parts, serve to increase the rigidity of the rafter legs, support the ridge, and connect individual parts into an overall structure.

In addition to the mentioned design details, it may also include other elements, the functions of which are aimed at strengthening the system and optimally distributing roof loads on the walls of the building.

The rafter system is divided into several categories depending on the various features of its design.

Attic space

Before moving on to considering different types of roofs, it is worth understanding what an attic space can be, since many owners successfully use it as utility and full-fledged residential premises.

The design of pitched roofs can be divided into attics and attics. The first option is called this way because the space under the roof has a small height and is used only as an air layer insulating the building on top. Such systems usually include or have several slopes, but located at a very slight angle.

An attic structure that has a sufficiently high ridge height can be used in different ways, be insulated and not insulated. These options include attic or gable option. If you choose a roof with a high ridge, then mandatory it is necessary to take into account wind loads in the region where the house is built.

Slope slope

To determine the optimal slope of the roof slopes of a future residential building, first of all you need to take a closer look at the low-rise neighboring houses that have already been built. If they have been standing for more than one year and can withstand wind loads, then their design can safely be taken as a basis. In the same case, when the owners set a goal to create an exclusive original project, unlike standing nearby buildings, it is necessary to familiarize yourself with the design and operational features of various rafter systems and make the appropriate calculations.

It should be taken into account that the change in tangential and normal values ​​of wind force depends on how large the slope of the roof slopes is - the steeper the slope angle, the higher value have normal forces and less tangent forces. If the roof is flat, then the structure is more affected by the tangential wind load, since the lifting force increases on the leeward side and decreases on the windward side.

Winter snow load should also be taken into account when designing the roof. Usually this factor is considered in conjunction with the wind load, since on the windward side the snow load will be much lower than on the leeward slope. In addition, there are places on the slopes where snow will certainly accumulate, putting a large load on this area, so it should be reinforced with additional rafters.

The slope of roof slopes can vary from 10 to 60 degrees, and it must be selected not only taking into account the consolidated external load, but also depending on the roofing covering that is planned to be used. This factor is taken into account because roofing materials differ in their weight; to secure them, a different number of elements of the rafter system is required, which means that the load on the walls of the house will also vary, and how large it will be also depends on the angle of the roof. Of no small importance are the characteristics of each coating in terms of resistance to moisture penetration - many roofing materials in any case require one or another slope to ensure the free drainage of storm water or melting snow. In addition, when choosing a roof slope, you need to think in advance about how the cleaning process will be carried out and repair work on the roof.

When planning a particular angle of the roof slopes, you need to know that the fewer joints between the sheets of roofing, and the more airtight they are, the less you can make the slope of the slope, of course, if you are not planning to arrange a residential or utility room in the attic space.

If a material consisting of small elements is used to cover the roof, for example, ceramic tiles, then the slope of the slopes must be made steep enough so that water never lingers on the surface.

Considering the weight of the roofing material, you need to know that the heavier the covering, the larger the angle of the slopes should be, since in this case the load will be correctly distributed over the rafter system and load-bearing walls.

The following materials can be used to cover the roof: or profile sheet, galvanized steel, corrugated asbestos concrete and bitumen-fiber sheets, cement and ceramic tiles, roofing felt, soft roofing and other roofing materials. The illustration below shows the permissible slope angles for various types roofing coverings.

Basic designs of rafter systems

First of all, it is worth considering basic types rafter systems relative to the location of the walls of the house, which are used in all roof structures. Basic options are divided into layered, hanging, and combined, that is, including elements of both the first and second types of systems in its design.

fastenings for rafters

Layered system

In buildings where internal load-bearing walls are provided, a layered rafter system is often installed. It is much easier to install than a hanging one, since the internal load-bearing walls provide reliable support for its elements, and in addition, this structure will require less materials.

For rafters in this system, the defining reference point is the ridge board, on which they are fixed. The non-thrust type of layered system can be arranged in three options:

• In the first option, the upper side of the rafters is fixed on a ridge support, called a sliding one, and their lower side is fixed by cutting to the mauerlat. Additionally, the rafters in the lower part are fixed to the wall using wire or staples.

• In the second case, the rafters in the upper part are cut at a certain angle and connected to each other using special metal plates.

The lower edge of the rafter legs is attached to the Mauerlat with movable fasteners.

• In the third option, the rafters are rigidly fastened in the upper part with bars or treated boards located horizontally, parallel to each other on both sides of rafters connected at an angle, and a ridge girder is clamped between them.

In the lower part, to secure the rafters, just as in the previous case, they are used sliding fastenings.

It is necessary to explain why sliding fasteners are often used to secure rafters to the mauerlat. The fact is that they are able to relieve load-bearing walls from excessive stress, since the rafters are not rigidly fixed, and when the structure shrinks, they have the ability to move without deforming general design roofing system.

This type of fastening is used only in layered systems, which also distinguishes them from the hanging version.

However, in some cases, for layered rafters, a spacer system is used, in which the lower end of the rafters is rigidly fixed to the Mauerlat, and to relieve the load from the walls, tie-downs and struts are built into the structure. This option is called complex, as it includes elements of a layered and hanging system.

Enter the requested values ​​and click the "Calculate rafter length" button

Excess value Lbc (meters)

Length of the horizontal projection of the rafter Lсд (meters)

Calculation conditions:

Required width of eaves overhang (meters)

Number of overhangs:

Gable rafter system

Gable rafter systems are the most popular for one-story private houses. They look neat, fit well into any style of construction, are reliable and can be used, depending on the angle of their slope, for arranging an attic under living rooms, utility rooms or simply to create an air gap that retains heat in the building.

wood screws

For a durable and reliable roof, it is important to make all components of the rafter system with high quality. We'll figure out what this means right now.

Rafters are the skeleton of the roof, which supports the internal and external cladding, insulation, waterproofing and other elements. They are also very often used as the basis for communications. The roof and, accordingly, the rafters are subject to enormous loads, which can reach 200 kg/m2. This is the weight of building materials, snow with leaves and other debris. What are the gusts of wind worth?

Roof rafters as a basis for communications

When carrying out repair work, this system must withstand not only the weight of a person, but also the necessary equipment. Moreover, all these parameters are strictly individual and depend on a number of factors, ranging from configuration to climatic zone. However, in any case, the roof and all its elements must be sufficiently reliable, and only then can we feel truly protected.

First you need to familiarize yourself with the terminology. The foundation of the entire system can rightly be called the Mauerlat. It is a beam on which the structure is attached. Its main function is to uniformly distribute loads on the walls. But the beam on which the sheathing is fixed is called rafter leg. This is the most important element that determines the angle of inclination of the slope and the general appearance of the roof. The rafter legs are held together by the purlin. It is located both on top and on the side. Depending on this, there are ridge and side runs. The lower part of the legs is secured with a tightening.

Mauerlat for fastening the truss structure

Thanks to the struts and racks, the rafter beams are positioned as stable as possible. Edged boards are laid perpendicular to the legs - sheathing. It serves as the basis for the roofing material. And the junction of the roof slopes is usually called the ridge. A continuous sheathing is placed on it to make this part of the roof as reliable as possible. The continuation of the rafter legs is the fillies. They are located under an overhang that protects the walls from precipitation. Very often these structural elements are the first to begin to rot, since they are most susceptible to negative influence weather conditions, while the legs themselves can serve for a very long time. The reliability of the entire structure depends on how high quality absolutely each fastening unit is. We will talk about them in more detail.

This concept combines a number of structural elements, since they consist of sheathing, racks and braces. In fact, this rigid structure is the skeleton of the roof. Depending on the size and personal wishes, there are four types of farms. If the width of the house is from 12 to 24 m, then a segmented or trapezoidal shape would be most suitable. For larger structures, up to 36 m wide, a polygonal one is suitable. But the classic triangular one will be an excellent solution for the construction of houses with a width of 9–18 m.

Roof trusses of different sizes

The material also plays a huge role. The most commonly used material is wood. In this case, the installation of beams occurs by cutting and subsequent fixation with nails, screws and other fasteners. However, the use of wood is not relevant in all cases. So, if the span length exceeds 16 m, then trusses with stretched metal posts will be more suitable, since they will ensure reliable fastenings wooden elements in this case it will be difficult. Still popular combined type, which simultaneously uses both wood and metal parts.

A ridge is a horizontal edge at the junction of two slopes. There is a suspended and hanging type rafter system. In the first case, the skate is installed on racks located parallel long walls. It is very important to ensure maximum contact between the rafters and the ridge; for this purpose, appropriate cuts are made. Fixation is done with nails.

Skate at the junction of two slopes

If we are talking about a hanging structure, then the ends of the rafter legs are connected in pairs. To ensure such a connection, the end of each beam is cut at an angle equal to the slope of the roof. Next, the rafters are connected by cut planes and fixed with nails driven at an angle. It is imperative to cover the joint with a metal plate or wooden overlay.

Pair connection of rafter legs

When connecting by cutting into half a tree, maximum strength is achieved. To do this, at the junction, the rafter legs are connected to the ledge. Then a hole is drilled for a 14 mm bolt. Further fixation is achieved through bolted connections. When it comes to a sliding system, in this case the ends of the legs are connected by means of metal plate hinges.

This is the next attachment point for rafter systems, which we need to look at in more detail. There are two technologies for fixing beams to the Mauerlat. Rigid mounts exclude any shifts, vibrations, turns, torsion and other manipulations. To achieve a similar effect, a gash is made on the leg. Next, the connection is additionally fixed with nails, wire, screws and other auxiliary elements. Usually several nails are driven in at an angle so that they intersect inside the Mauerlat. And then another nail is driven in vertically.

Washed down on the legs for attachment to the Mauerlat

Sliding fastenings are obtained thanks to special fasteners. There are one, two or three degrees of freedom of this coupling. This connection is perfect for wooden houses, since rigid fixation may be severely damaged during shrinkage. Such a mobile connection can be achieved in several ways. The leg rests against the Mauerlat with a hemmed block or sawn tooth and is rigidly fixed using a metal corner. In this way, rigidity of the fastening in the horizontal plane is achieved. In the upper part, the legs are connected by notches, while a bevel is made on the horizontal platform to ensure a sliding connection.

Sliding element fastenings

If you drive only one nail at the place of fixation to the Mauerlat or use special flexible plates, then the connection will be sliding in this part of the rafter system.

Now let's look at the typical components of a wooden rafter system. A special feature of this roof is the presence of hips. This type has a number of advantages. They are more durable, since the load is distributed evenly over the entire surface, and are not afraid of strong winds and precipitation, economical. However, they are more complex technologically.

Typical hip roof components

This roof consists of two long trapezoidal slopes, although they do not cover the entire area; triangular hips are installed at the ends of the building at an angle. In this case, typical elements appear - additional slanted rafter legs, from which the end slopes are formed. The connection of diagonal beams can be different. Both hanging trusses and a layered structure fixed to the mauerlat are popular.

Roof made of trapezoidal slopes and triangular hips

If the rafters of the slopes rest on the ridge, then the sloping legs should be adjacent to the console of the ridge girder. It is very important that the console outlet be at least 100 mm, but not more than 150 mm. The lower part of the diagonal rafters is fixed to the Mauerlat or a special beam on the wall of the house. Sometimes wooden beams are used to make rafter legs; in this case, the mowing elements are fixed to a special board (beater) fixed to the truss. But the installation to the outer hanging truss is done using a truss. In this case, be sure to make cuts on the leg beams at an angle corresponding to the inclination hip stingray.

All kinds of wooden buildings, both residential and utility, remain in demand, even despite a wide range of modern building materials. During their construction, competent roof construction plays an important role, since only in this case the buildings will be truly warm and durable.

Wood has always been used as a building material. Wherever forests predominated, it was the most reliable and available material For local residents. They not only built houses from wood, but also covered them with roofing. Wooden roofing copes well with the functions of moisture and heat protection, not to mention exclusive appearance. Wood roofing still occupies a leading place among roofing materials today.

Types of wooden roofing

For the installation of such a roof they use various materials made of wood:

• Shingles look like thin planks made from alder, spruce and aspen. It is laid in layers, maintaining a checkerboard pattern. There can be four or six layers. Shingles are an excellent heat insulator and do not allow noise to pass through. Condensation does not accumulate under such a roof, so additional ventilation is unnecessary.
• Shindel are split planks of irregular shape. As it is also called, wooden shingles are laid with an overlap in a checkerboard pattern. To make the material, hard wood is used, for example, larch or Canadian red cedar.
• The ploughshare, spade-shaped planks, is well known to us from images of royal chambers or boyars' mansions. Even today, domed and hipped roofs are usually covered with this material.
• Shingles are planks that are cut with a saw. This is a fairly versatile material and is suitable for roofs of various configurations and areas.
• Tes, as the name suggests, are boards that are hewn directly from a tree trunk. Therefore, the structure of the wood is clearly visible on them. The main raw materials for them are conifers.

Advantages and disadvantages

Among the advantages of this coating, we first note its environmental friendliness wooden roof.

• its device does not require the use of high-tech equipment and complex instruments;
• the coating is completely sealed;
• there is no need to lay a vapor barrier layer;
• under such a roof it is warm in cold weather and cool in hot weather;
• light weight;
• excellent sound absorption:
• exceptionally long service life - about one hundred years.

Of course, there is of this type coatings and imperfections, e.g.

• high price level;
• complexity of installation;
• low fire safety.

However, they do not in any way affect the desire of homeowners to have a really beautiful and environmentally friendly home.

Installation Features

A wooden roof is the result of several manufacturing operations. To perform them, you need tools for woodworking, as well as special devices. Its durability and stability are largely due to the competent organization of installation work: whether it is convenient equipment or the quality of connecting the nodes of wooden roof structures.

During the installation process, various methods of connecting parts are used, for example, simple nails, spikes, or others.

Let's consider the structure of the main components of a wooden roof : locks, notches, tenons.

Carpenter's Castle. The joints of wooden parts acquire strength, thereby increasing the rigidity of the structure. There are two types of locks

• onlay. They are the simplest to implement. In everyday life, you can more often hear another name - half-tree, since the sampling on a workpiece in the form of a rectangle is made to half its thickness. Overlay parts can be connected at an angle of 90˚, T-shaped or crosswise. After joining the workpieces, they are fastened either with nails or dowels, or with glue. The fastening option depends on the expected loads at the junction;
• into the frying pan. This is a more difficult option to execute, but, on the other hand, these locks are resistant to high operating loads. To connect parts of the same thickness, use a simple frying pan. On one of the blanks a trapezoid is cut out from the end, on the other - a nest, similar in both shape and size. If a simple frying pan is supplemented with cutting, then it will also be possible to connect parts with different thicknesses. In this case, the depth of the nest should correspond to the thickness of the first workpiece.

Tenon connection- the most aesthetically pleasing, but their execution requires high qualifications. It consists of two elements - a spike and a socket or eye, located on two parts. The tenon is a protrusion that is located at the end of the first and fits into the eye on the second. The tenons and sockets must be adjusted so that the wood fibers do not collapse when they fit tightly into each other. If the fit is too tight, the wood in the spaces between the joining elements may peel off, but if it is loose, the result will be a weak joint.

Rafter notches used in the construction of rafter legs. The method of making cuts of this type has some peculiarities, since the rafter and floor beams are located at an angle. When constructing roofs, stops and so-called frontal notches are more often used, since they are very reliable and at the same time they are not difficult to perform.

This is a type of connection where forces from one part are transferred to another part without intermediary working connections. If we are talking about installation loads, then to transfer them it is necessary to install auxiliary metal fasteners: bolts, brackets, pins or others.

On a note

When constructing a wooden roof log houses, roofing components are made using the same fasteners.

Installation technology

• Board roofing. It is laid in two ways:

1. transverse, which involves laying boards parallel to the ridge;

2. longitudinal, the boards in this option are laid parallel to the gable eaves of the slope.

Laying is done:

• in one row. Each subsequent board overlaps the previous one by 50 mm;
• two rows. The middles of the boards of the next row should be aligned in this case with the joints of the boards in the previous one. For residential buildings, it is recommended to use double-row installation.

In the upper part of the plank covering it is necessary to provide a special groove designed to drain water.

• Shingle roof. Installation of shingle coverings (shingles, shingles, ploughshares) is more complicated and more labor-intensive. Typically, roofing elements are fastened using nails, preferably copper.

On a note

For some types of wooden coverings, the tenon and groove fastening principle is used.

A shingle roof is assembled onto a solid or sparse sheathing made of timber with a cross-section of at least 50 mm. The pitch of the sheathing should be equal to one third of the length of the shingles. For outbuildings, two-layer masonry is used; for residential buildings, three-layer masonry is more suitable.

Important points about the device

• Wood coverings, as a rule, are laid on pitched roofs with an angle of inclination of at least 25˚.
• On outbuildings it can be flat. Such a roof requires the presence of a waterproofing layer, say, made of roofing felt. Waterproofing material laid on a flat base made of sheet material. In extreme cases, it can be laid out from boards, maintaining a gap between them of no more than 10 mm.
• By traditional technology Wood covering devices, waterproofing is optional. Nevertheless, today many craftsmen still recommend laying membrane films under the coating.
• The membrane is spread over the rafters, then a counter-lattice made of timber is placed on top of the waterproofing layer on the rafters. Then the sheathing under the main flooring is assembled along it.
• On steep slopes, it is enough to apply waterproofing only in problematic areas of wooden roofs, for example, on valleys, along eaves, in places where pipes pass, etc.
• Installation of shingles begins from the middle of the eaves. The elements of the initial row are laid as tightly as possible, and they should protrude beyond the cornice.
• Each subsequent row is laid with such an overlap as to cover the joints of the previous two.
• Roof ridges are decorated with special ridge elements. They are laid overlapping and fixed along the lower edge with nails.

In order for a constructed building to last for more than one year, it needs both a reliable foundation and strong system roofs that can withstand the vicissitudes of the weather. The roof must withstand heavy loads with dignity: heavy snowfalls, sharp gusts of wind, heavy downpours. The roof truss system is best suited for this.

Roof trusses and its types

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

The dimensions and design of the rafters depend on:

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

The rafter system has:

• sheathing - beams laid perpendicularly on the rafter legs;
• ties that absorb tensile forces;
• wooden racks located in a vertical position;
• mauerlat - a beam, the installation of which is carried out along the wall, the rafters rest on it;
• rafter legs are a kind of wooden beams that bear the main load of the roof.

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

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

Characteristics of hanging rafters

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

If the roof of the house complex design, types of rafters can be alternated. For example, if there are supports or a middle main wall, layered rafters are installed, and if there are no such elements, hanging rafters are installed.

Features of layered rafters

For a layered rafter system, the house must be additionally equipped load-bearing wall, located in the middle. Layered rafters are distinguished according to the following characteristics:

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

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

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

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

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

Roof trusses for various roof types

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

Rafter truss for gable roof

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

The rafter system of a gable roof includes two rectangular inclined planes. Top part The front side of the building resembles a triangle. Main components gable roof- this is the mauerlat and rafter legs. In order to properly distribute the load across the rafters and walls, struts, crossbars and racks are installed, thanks to which you can create a durable, rigid, elementary and lightweight structure for installing a structure for a gable roof.

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

You can install sparse or solid sheathing on top of the rafters, and then attach bitumen coating, tiles or some other type of material to it. The rafters and the sheathing itself are usually made of beams or boards, which are fastened with nails, bolts or metal fasteners. Metal profiles can be used as rafters, thereby covering significant spans. There is no need to use extra racks and struts.

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

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

Rafter system for hip roof

When arranging a system for a hip roof, installation will be required different types rafters:

• narozhniki (short);
• lateral;
• hip main;
• obliques (diagonal elements that form a slope in the shape of a triangle).

The rafter legs, located on the side, are made of boards, and they are mounted identically to the parts of a traditional pitched roof with a pitched or hanging structure. Hip main rafters are layered parts. For splices, boards or bars are used, attached not only to the Mauerlat, but also to the diagonal beams.

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

To prevent the hip roof from deforming from heavy loads, you should accurately calculate the angle of inclination of the diagonal beams for the rafters

Maintain symmetry when installing diagonal beams for rafters, otherwise the roof will deform under significant load.

Rafter system for a sloping roof

A broken roof is a structure with rafters that consist of several individual elements. Moreover, they should be located at different angles relative to the horizon. And since the bottom rafter part is located almost vertically, the attic space of the building receives additional area, thanks to which it can be used as residential. The installation of this type of roof is carried out during the construction of a four- or gable rafter structure.

Calculate four-slope system rafters are needed by professionals, but you can make a gable sloping roof yourself, since its installation is very simple. To do this you need to install support frame, which should consist of purlins as well as racks. Horizontal parts are secured with hanging rafters. But the supports are attached to the Mauerlat sloping roof shortened rafter legs.

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

"Cuckoo" in a roof truss

The so-called cuckoo on the roof is a small protrusion that is located on attic floor. Here is a window for better lighting attic room. The installation of the “cuckoo” is carried out carefully, while monitoring the parameters of the entire structure: depth of cut, angle of inclination and other factors. However, before this, the necessary measurements are made.

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

After the installation of the roof truss is completed, sheathing is laid, the type of which depends on the roof covering purchased. Installation of the sheathing is done continuously or with a certain step. Boards, OSB and plywood sheets are usually used for it. In addition, the installation of roofing material must be identical throughout the entire roof.

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

A “cuckoo” on the roof is a small protrusion on the attic floor, under which there is an additional window.

Chalet roof rafter truss

The peculiarity of this design is that the canopies and overhangs are moved outside the house. In addition, there must be rafters and roof beams extending up to three meters on the sides of the building. Each of these elements is secured with a bracket to the wall of the building in the lower part. Next, tie the edges of the beams. They serve as a support for covering the roof of the building.

But creating large overhangs, it is necessary to install the reinforced belt in parallel with the installation of studs for the Mauerlat. It is necessary to make anchors that help secure the consoles. In this case, the rafters will be perfectly fixed with anchors and, in addition, with mortises.

To carry out the side cornices, a ridge beam is made, after which beams are placed at the level of the mauerlat, which must be identical to the length of the ridge. The truss, and subsequently the building materials for the roof, rest on these structural details.

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

A chalet-style roof is characterized by canopies placed several meters outside the house

Rafter truss designed for soft roofing

Soft roofing is done different ways, however, there are common characteristics in the technological methods of its construction. Initially, you need to prepare. When arranging a roof for a house made of foam concrete or other material, a mauerlat is first installed, then in the upper crowns of the building a cut is made for the ceiling beams in increments of up to one meter. The distance between the boards is calculated based on the type of rafter structure.

1. Install individual parts of the rafter system. To completely eliminate the risk, the rafter boards are attached to the ground with screws. After the roof truss is created, it is raised to the top of the building.
2. Secure all elements of the rafters to the ceiling, internal boards, jibs, as well as crossbars. Further, this base for the roof will become a single whole structure.
3. The next stage is the sheathing, which is installed under the soft roof with small gaps or no gaps at all. Gaps of no more than 1 cm are allowed. Quite often, leveling plywood is installed on top of the boards. Its sheets are laid according to the method brickwork. The resulting joints are not aligned with the gaps between the plywood and the board.

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

Self-production of the rafter system

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

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

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

1. A template is made according to which the truss is assembled. Take 2 boards corresponding to the length of the rafters and connect them together at just one edge with a nail.

   A template for rafters called “scissors” will help you quickly assemble the entire roof rafter system

2. The result is a design called “scissors”. Its free edges are placed on supports at the points of contact between the rafter legs. The result should be the final angle, that is, the angle at which the roof slope will be inclined. It is fixed with several long nails and transverse boards.
3. A second template is made, thanks to which the cuts are installed on the rafters. It is made from plywood.
4. Special mounting cuts are cut on the rafters (a prepared template is used for these purposes) and connected at an angle of inclination of the slope. You should end up with a triangle going up the stairs to the roof. Next, it must be attached to the Mauerlat.
5. Initially, two side gable rafters are installed. Their correct installation in the vertical and horizontal planes occurs due to temporary struts attached to the rafters.

   For proper installation of the entire rafter system, the first pair of rafters is installed on the roof

6. A cord is stretched between these tops of the rafters. It will indicate the future ridge and the level of other rafters located in the gap.
7. Raise and install the remaining rafters at the initially calculated distance, which should be at least 60 cm from each other.
8. If a bulky rafter structure is envisaged, then it is additionally strengthened with struts, supports, and so on.

   The bulky structure of the rafters is additionally strengthened with struts and supports

9. A ridge beam is installed on special supports, to which not only short, but also diagonal and intermediate elements of the rafters are attached.

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

Typical components of a standard rafter system

The strength of the rafter structure depends on the ideally selected section of the boards, as well as on High Quality rafter nodes. The connection of parts for the roof structure is done according to established rules.

Main typical units in the rafter system:

• rafter support assembly on the mauerlat;
• ridge;
• unit for combining the top ties and the entire rafter system;
• securing the strut, rack, as well as rafters and beams.

After the design of the rafter system has been chosen, it is necessary to draw up a plan in which to highlight all the nodes. They are made differently in each design as it depends on different nuances: type of roof, its size, angle of inclination.

Rafters from profile pipe is a metal structure that is assembled using lattice rods. The production of such farms itself is a very labor-intensive process, but also more economical. To make rafters, paired material is used, and gussets are connecting elements. The structure of the rafters from profile pipes is assembled on the ground, using riveting or welding.

Thanks to such systems, any spans are blocked, but the correct calculation must be made. Provided that all welding work is done efficiently, in the future all that remains is to transfer the structural elements to the top of the building and assemble them. Load-bearing rafters made from profile pipes have many advantages, such as:

Crossbar in the rafter system

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

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

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

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

The fastening is available with a mortise or overhead. In general, the crossbar is a design unit, as is the entire system of roof slings.

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

Fastening the rafter system

To ensure the reliability of the rafter system, you must first find out how they are attached to the supporting roof and ridge. If a fastening is made to prevent deformation of the roof when the house shrinks, then the rafters are secured on top with a hinge plate or a nut and bolt, and below with a sliding support.

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

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

In the layered system, the rafter legs are not connected to each other, since they are attached to the ridge girder.

The rafters are attached to the mauerlat using the cutting method, which is made in the rafter leg. Thanks to this fastening method, the roof support will not weaken. Cutting is also done when installing rafters on floor beams. In this case, a cut is also made in the support beam.

Video: how to make rafters with your own hands

Thus, an ideally selected rafter system and their design characteristics will help create the basis for a reliable roof for your home.