A series of knots of wooden roofs of public buildings. Roof truss system. Sloped truss systems

The roof system is the part of the roof structure on the outside that is supported load-bearing structure. It includes a crate and a truss system. The triangle underlying this system should be a rigid and most economical structural element that contains the attachment points for the roof rafters.

The main characteristics of the nodes of the truss system

The main attachment points of the roof truss system are shown in fig. 1. They imply the presence of a rafter leg (Mauerlat - 1), a rafter leg ( ridge run- 2), racks (puffs - 3). The design of the truss system is the main load-bearing element of the roof.

All roof attachment points must be of sufficient strength to eliminate a significant degree of risk associated with roof collapse. The consequences of a mistake made when connecting elements can be the most unpredictable.

Figure 1. The main attachment points of the roof truss system: 1 - mauerlat, 2 - ridge run, 3 - puffs.

First, the rafters are installed on the Mauerlat if the building has brick walls. Similar nodes are provided for concrete blocks, then it is necessary to create a reinforced concrete stiffening belt, and it is necessary to insert studs into its design. Their location should be at a distance of 1 to 1.5 m from each other, and their diameter should be more than 14 mm. The top of the studs must be equipped with a special thread.

Mauerlat is drilled, making holes that are necessary for attaching elements to it. Each of the holes must be the same size as the diameter of the stud, and its pitch must correspond to the distance between the studs. A nut is put on each protruding end of the stud and tightened, which ensures the strength of the connection between the Mauerlat and the wall. The rafters should be connected to the Mauerlat in such a way that their weakening does not occur. bearing capacity.

Description of the main fasteners for mounting the truss system

If during the construction of the house a rounded log or timber was used, then it is not necessary to create an armored belt. produced on the upper beam or on the log of the wall. For this purpose, Mauerlat connections with rafters are used different ways notch (notch).

What fasteners fasten metal rafters:

Plates.
Fasteners LK.
corners.
Brackets WW.
Self-tapping screws.
Varieties of the corner of the KR.
Wire ties.
Mounting tape perforated TM.
Bolts with nuts.
Brackets WW.

If brackets are used when connecting the rafters to the Mauerlat, then they are not cut into the rafters, which helps to strengthen the bearing capacity. Metal brackets are usually produced, and the metal is galvanized and has a thickness of 0.2 cm. The brackets are strengthened with nails, anchor bolts or screws.

You can use the LK fastener by creating attachment points not only for rafters with a Mauerlat, but also for various other elements that make up the roof structure. Fastener LK is fixed to wood, like brackets, with the exception of the use of anchor types of bolts.

Mounting perforated tape allows you to strengthen the connecting nodes in the construction of roofing systems. It is used not only to create stronger nodes, but also to strengthen elements for additional use in order to give rigidity or strength to the system as a whole. They fix the perforated mounting tape with screws or nails, so it is used to strengthen the structure of the rafter system of any roof, the integrity of which will not be violated.

With the use of KR corners and their various modifications, the attachment points are reinforced so that they can effectively participate in the connection of the Mauerlat and rafters. Ensuring appropriate strength of the roof units is permissible when using corners, which improves the load-bearing characteristics of the roof structure.

The use of connecting elements made of metal is not associated with the insertion of corners into the roof system. This will not cause a decrease in the bearing capacity of the roofing system. You can use corners for connection using screws or nails, the protrusions of which resemble a ruff.

How are the knots connected in the ridge part?

There are three main types of fastening in the ridge parts of the roofing system:

Butt connection.
Mounting on the basis of a ridge run.
Ridge joint overlap.

For the purpose of fastening, the ridge part is cut off in the first way with top edge at an angle that is the same as the angle of the roof slope. Then he is pushed into necessary rafter, which should also be cut at an angle, but on the opposite side of the roof. A special template is sometimes used to trim corners.

Nails for connecting the rafters under the ridge should be 150 mm or more in size, two of them will be needed. Each nail is driven into the rafters at the top of the rafters at the appropriate angle. The sharp end of the nail usually enters the cut of the rafter from opposite sides. Strengthening the ridge joint can be achieved by applying a metal plate to it from the side or wooden lining so that it is enough to pull it with bolts or nails.

The connection in the second way, that is, through the ridge run, is associated with the strengthening of the rafters on the ridge beam. The run is one of the additional support beams or beams, which is a support for the rafters. It is located parallel to the ridge or Mauerlat. The method differs from the previous one in that between the rafters, which are sawn at an angle, a ridge beam is laid, which is a laborious process, therefore this way used less often.

A more common method is similar to the first, but it differs in that the fastening is overlapped, and the joint method is not used. The rafters should be in contact with the ends, and not the side surfaces. The rafters should be pulled together with a bolt or hairpin, nails. This connection is used by many masters in practice.

In general, it is possible to install rafters on a Mauerlat by creating structures for roof truss systems that are expansion or non-expansion. This determines the choice of the appropriate method of connecting the power plate and rafters, which can be similarly strengthened to the ridge.

The main shortcomings in the installation of attachment points for the truss system

The problem of choosing the method of attaching the truss system to the structure of the building is very important when creating attachment points. Often, when creating nodes, the Mauerlat serves as a support for the rafters. The fastening of the Mauerlat beam is carried out “tightly” with the help of anchor bolts to the reinforced stiffening belt.

A possible drawback is an unanchored stiffening belt, which can lead to the overturning of the Mauerlat beam and the stability of the roof truss system. There is a loosening of the roof, and the roof is sliding down. Due to erroneous placement of anchor bolts or incorrectly made holes, the fastening is no longer effective.

If the nuts are screwed onto the bolts with an overtightening, then the fastening assembly becomes fragile and is subject to rapid destruction. In this case, wire twisting is sometimes used to create an attachment point.

During the construction of the truss system, the safety of the joints should be observed.

For example, if roof structure combined with the floor without taking into account the bearing capacity of the attic floor, then this is the most dangerous moment that can lead to the destruction of the building.

If the tightening is changed to a precast concrete floor beam designed for bending, then the use of prefabricated reinforced concrete beams should be effective due to their rigid fixation in reinforced belt floor stiffness, which is arranged using reinforcing cage. Its axis must go in the same direction as the acting forces.

At the same time, the presence of shortcomings in the process of creating a truss system, which is a load-bearing wooden floor structure, often arises due to a misunderstanding of the functions performed by the puff and crossbar throughout roofing system. The puff differs from the crossbar in that it is a longitudinal, and the crossbar is a transverse beam.

The construction of the truss system is associated with the creation of a spacer system that works on the principle of divergence at the bottom of the planes, which occurs under the influence of not only their own weight, but also the load that falls on the line of intersection of the planes, which should be prevented by the transverse beam, that is, tightening.

Getting to the roof device, you should find out all the points associated with the assumption of certain errors that occur when performing work on the installation of the truss system. The device of the roof of the house is associated with possible difficulties and shortcomings that do not allow achieving the goal.

When designing any residential building, architects pay special attention to the roof, as it performs not one, but several functions at once, depending on its design features. I must say that not all future homeowners are satisfied with the usual 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 more complex structures, which add a special attraction and originality to the structure. Other, more practical homeowners prefer attic structures, which are simultaneously capable of performing the role of a roof and a second floor.

The basis of any roof is an individual truss system, which has its own design features. Making the choice of the desired roof frame will be much easier if you figure out in advance which ones types and schemes of truss systems used in building practice. After receiving such information, it will become more clear how complex such structures are in installation. This is especially important to know if the roof frame is supposed to be built independently.

The main functional tasks of truss systems

When arranging pitched roof structures, the truss system is a frame for covering and for holding materials of the "roofing pie". With proper installation frame structure will be created the necessary conditions for correct and non-insulated types of roofs that protect the walls and interior of the house from various atmospheric influences.

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

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

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

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

If the area where the construction will be carried out is famous for its winds, then it is better to choose a structure with a slight slope of the slope so that the sharp gusts that occur do not rip off individual elements of the roof and roof.

The main elements of the roof structure

Details and nodes of truss systems

Depending on the type of truss system chosen, the structural elements used can vary significantly, however, there are details that are present in both simple and complex roof systems.

The main elements of the pitched roof truss system include:

Rafter legs forming roof slopes.
- wooden beam, fixed on the walls of the house and serving to fix the lower part on it rafter legs.

The ridge is the junction of the frames of two slopes. He 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 (run).
Sheathing - these are slats or beams mounted on rafters with a certain step and serving as the basis for the flooring of the selected roofing material.
Retaining elements, where you can take beds, girders, racks, struts, ties and other parts, serve to increase the rigidity of the rafter legs, support the ridge, link individual parts into a common structure.

In addition to the above structural details, other elements can be included in it, the functions of which are aimed at strengthening the system and optimal distribution of roof loads on the walls of the building.

The truss system is divided into several categories depending on different features of its design.

attic space

Before proceeding to review different types roofs, it is worth figuring out what an attic space can be, as many owners successfully use it as utility and full-fledged living quarters.

The design of pitched roofs can be divided into non-attic and attic. The first option is called just that because the space under the roof has a small height and is used only as an air layer that insulates the building from above. Such systems usually include or have several slopes, but located at a very slight angle.

The attic structure, which has a sufficiently large ridge height, can be used in different ways, be insulated and not insulated. These options include attic or gable option. If a roof with a high ridge is chosen, then in without fail 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 the future residential building, first of all, you need to look at the already built low-rise neighboring houses. If they have been standing for more than one year and steadfastly withstand wind loads, then their design can be safely taken as a basis. In the same case, when the owners set the goal of creating an exclusive original project, unlike the buildings standing nearby, it is necessary to familiarize yourself with the design and operational features of various truss systems and make appropriate calculations.

It should be borne in mind that the change in the tangent and normal values \u200b\u200bof the wind force depends on how large the slope of the roof slopes is - the steeper the angle of inclination, the greater value have normal forces and smaller tangents. If the roof is sloping, 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 combination with the wind load, since the snow load on the windward side will be much lower than on the leeward slope. In addition, there are places on the slopes where snow will definitely collect, giving a big load on this area, so it should be strengthened with additional rafters.

Roof slopes can vary from 10 to 60 degrees and must be selected not only with regard to the consolidated external load, but also depending on the roofing that is planned to be used. This factor is taken into account because roofing materials differ in their mass, their fixing requires a different number of elements of the truss system, 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 slope. Equally important are the features of each coating in terms of resistance to moisture penetration - in any case, many roofing materials need one or another slope to ensure free descent storm water or melting snow. In addition, when choosing a roof slope, you need to think in advance 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 the coating, and the tighter they are, the less you can make the slope of the slope, of course, if it is not supposed to be arranged in attic space residential or business premises.

If, however, 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 the water never lingers on the surface.

Given the weight of the roofing material, you need to know - the heavier the coating, the greater the angle of the slopes should be, since in this case the load will be correctly distributed to the rafter system and load-bearing walls.

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

Basic structures of truss systems

First of all, it is worth considering the basic types of truss systems regarding the location of the walls of the house, which are used in all roof structures. The basic options are divided into layered, hanging, and also combined, that is, including elements of both the first and second types of systems in their design.

fasteners for rafters

Layered system

In buildings where internal load-bearing walls are provided, a layered truss 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, fewer materials will be required for this design.

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

In the first version, 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 with wire or staples.

In the second case, the rafters in the upper part are cut at a certain angle and interconnected using special metal plates.

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

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

In the lower part, sliding fasteners are used to fix the rafters, just as in the previous case.

It is necessary to explain why sliding fasteners are often used to fix the rafters on the Mauerlat. The fact is that they are able to save the 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, a spacer system is used for layered rafters, in which the lower end of the rafters is rigidly fixed to the Mauerlat, and in order to remove the load from the walls, puffs and struts are built into the structure. This option is called complex, as it includes elements of a layered and hanging system.

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

Wood has always been used as a building material. Wherever forest tracts prevailed, she was the most reliable and available material for local residents. They not only built housing from wood, but also covered the roof with it. The wooden roof perfectly copes with the functions of moisture and heat protection, not to mention the exclusive appearance. The covering from wood and today occupies the leading place among roofing materials.

Varieties of wooden roofing

For the device of such a roof, various materials from wood are used:

Shingles in appearance are thin boards made of alder, spruce and aspen. It is laid in layers, maintaining a checkerboard pattern. Layers can be four or six. Shingles is an excellent heat insulator and does not let noise through. Under such a roof, condensate does not accumulate, so it is unnecessary to additionally arrange ventilation.
Shindel are split planks with irregular shape. As it is also called, wooden tiles are laid with an overlap in a checkerboard pattern. For the manufacture of the material, solid wood is used, for example, larch or Canadian red cedar.
Ploughshare, spade-shaped planks, are well known to us from the images of the royal chambers or boyar towers. Even today, domed and hipped roofs are usually covered with this material.
Gaunt is a plank that is obtained through a cut with a saw. This is a fairly versatile material, and it is suitable for roofs of various configurations and areas.
Tes, as the name implies, boards that are hewn immediately from a tree trunk. Therefore, the structure of wood is clearly visible on them. Their main raw material is conifers.

Pros and cons

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

its device does without the use of high-tech equipment and sophisticated tools;
the coating is completely sealed;
no need for laying a vapor barrier layer;
under such a roof it is warm in frosts and cool in the heat;
light weight;
excellent noise reduction:
exceptionally long service life - about a hundred years.

Of course, this type of coating also has disadvantages, for example,

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

However, they do not 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 competent organization installation work: whether it's comfortable equipment or the quality of the knot connection wooden structures roofs.

During the installation process, various ways connecting parts, for example, simple nails, spikes or more.

Consider the device of the main nodes of a wooden roof : locks, cuttings, spikes.

carpenter's castle. The joints of wood parts acquire strength, thereby increasing the rigidity of the structure. There are two types of locks

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

spike connection- the most aesthetic, but their execution requires high qualifications. It consists of two elements - a spike and a socket or eye, located on two parts. A spike is a protrusion that is located at the end of the first and enters the eye on the second. Spikes and sockets must be adjusted so that when tightly fitting into each other, the wood fibers do not collapse. If the fit is too tight, the wood between the joints may peel off, but if it is loose, a weak joint will result.

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

This is a type of connection where forces from one part are transferred to another part without intermediate working connections. If we are talking about mounting loads, then for their transfer it is necessary to install auxiliary fasteners made of metal: bolts, brackets, pins or other.

On a note

During the construction of the wooden roof of log houses, the roofing units are performed using the same fasteners.

Mounting technology

Tiled roof. It is laid in two ways:

transverse, which involves laying boards parallel to the ridge;

2. longitudinal, the boards in this option are laid in parallel gable cornice stingray.

Laying is performed:

in one row. Each subsequent board at the same time overlaps the previous one by 50 mm;
two rows. The middle 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 two-row laying.

A special groove must be provided in the upper part of the tesovy coating, designed to drain water.

Shingled roof. Installation of a shingle cover (shindel, shingles, plowshares) is more difficult and more laborious. Usually, roofing elements are fastened using nails, preferably copper.

On a note

For some types of wooden coatings, the tongue and groove fastening principle is used.

The shingle roof is assembled on a solid or sparse crate, stuffed from a beam with a cross section of at least 50 mm. The step of the crate should be equal to one third of the length of the shingle. For outbuildings, two-layer masonry is used; for residential buildings, three-layer masonry is more suitable.

Important points of the device

Wooden coverings, usually placed on pitched roofs with an inclination angle of at least 25˚.
On outbuildings, it can be flat. Such a roof assumes the presence of a waterproofing layer, say, from roofing material. waterproofing material laid on a flat base made of sheet material. In extreme cases, it can be laid out from the boards, keeping a gap of no more than 10 mm between them.
By traditional technology wood flooring devices waterproofing is optional. Nevertheless, today many masters still recommend laying membrane films under the coating.
The membrane is spread over the rafters, then a counter-lattice of timber is stuffed on top of the waterproofing layer on the rafters. Then, along it, a crate is assembled under the main flooring.
On steep slopes, it is enough to lay waterproofing only in problem nodes wooden roofs, for example, on valleys, along cornices, in places where pipes pass, etc.
Installation of shingles starts from the middle of the eaves. The elements of the initial row are laid as tightly as possible, and they should protrude beyond the eaves.
Each next row is laid with such an overlap to overlap the joints of the two previous ones.
Roof ridges are decorated with special ridge elements. They are overlapped and fixed along the lower edge with nails.

Private construction is unique in that most developers try to build a building with an individual touch. All possible design tricks, advice from friends and acquaintances can be used here, but whatever the house, it is very important to mount the main components. If it is built of wood, then the log house can be purchased at ready-made, and as for the roof, everything is more complicated here. The nodes of wooden roof structures are the most important part of the construction. They must be executed perfectly correctly so that the building will serve you as long as possible.

Knots of a wooden roof

If you have ever been present at the construction of the roof of a house, then you probably know that the rafter system is a kind of skeleton of the roof. A roofing cake is laid on them, a coating, with reverse side possibly sheathed facing material. Over their entire service life, the rafter legs hold colossal weights, which under certain conditions can reach the mark of 200 kilograms per 1 square meter. This value can be achieved if the owners do not maintain the roof and enough a large number of debris, leaves and snow.

At the time of construction of the roof, it must support the weight of several workers and their equipment. Such a load is purely individual, because it is difficult to predict the exact figures if you do not know how much the workers will weigh or what equipment they will take with them. Therefore, very often roofs are built in such a way that no matter how high the load, it can withstand it. Only in this case, work and further operation will take place in a calm and safe mode.

The next most important element is called Mauerlat or, in other words, the support beam. It is a kind of foundation for the entire roof. This element must be durable, therefore, in most cases, coniferous wood is used for its harvesting. Mauerlat can be attached to the wall in many ways, but the most popular and simple are: fastening using embedded parts or anchors. For the first method, special metal parts are laid in the process of building walls, and are released at the end.

The support beam holds the rafters, which means that it bears their weight and the load that they can withstand. The calculation for the selection of truss elements is quite simple and at the same time complex. It is very easy to calculate one equation, but it is not always possible to find all the nuances and insert them into the formula, so many developers simply take products with a large cross section and do not bother. This is partly true, but what if this is not enough. This problem can be solved with the help of all kinds of struts and props.

If you are faced with a volumetric roof, then the matter will not do without struts and racks. Thanks to these elements, the rafter legs feel as stable as possible. An important part of the entire system is the crate. It can be arranged by a discharged method or a continuous one. If the roofing material is hard, then you can use the first, and if soft, then only the second. As a rule, the discharged crate is stuffed over the eaves overhangs in a continuous way, thereby increasing the stability of the entire overhang and making it stronger.

The ridge knot is a very important part of any roof. It not only protects the two planes from dust and moisture, but also allows moist air to leave the attic. This is especially important when the coating or something in roofing cake completely isolates materials from moisture. Humid air has no choice but to begin to condense and destroy all elements of the truss system.

IMPORTANT: Before installing wooden elements, it is very important to process them protective compounds. Antiseptics protect the lumber structure from rotting and the growth of harmful microbes, and flame retardants increase fire resistance.

roof truss

On large slopes, trusses are indispensable. This design differs from an ordinary roof in that there are racks and braces here, which increase the maximum load on the wood several times. Often a farm is arranged all over the roof, but sometimes it can also be found locally.

It is advisable to arrange a truss truss if the width of your house is in the range from 12 to 24 meters. As a rule, trapezoidal or segmental trusses are arranged on buildings with large volumes. When the width of the building is even greater and this value does not exceed 36 meters, then a polygonal one will do. Standard designs with a width of 9 to 18 meters are content with triangular.

Beyond the Form roof truss The material from which it is made plays a very important role. In most cases, this is wood, but metal can also be used. Self-tapping screws or nails are used to fasten lumber together. In cases where the span is more than 16 meters, a combined truss is best suited. It includes elements of wood and metal.

The nuances of fastening rafter legs

As you already know, the nodes of wooden roofs are the most important component of the construction of a building, and what could be more important than fixing the roof frame. Rafter legs can be attached to the support beam in two ways.

hard
sliding

In the first case, you will get the most stable connection, which deprives the structure of all kinds of shifts, vibrations, turns, and similar manipulations. This can be achieved with a gash or a cut. After the leg is inserted into the created slot, it is fixed with nails, wire, anchors or any other fasteners.

Sliding docking looks very different. It has three degrees of freedom of conjugation. It should be noted right away that this method of fastening is most rationally used in wooden houses, since they tend to shrink a lot, as a result of which rigid knots can be seriously damaged. To create such an attachment, you will need to rest the rafter leg against the Mauerlat, where a tooth connection was previously arranged or an additional beam was nailed. Such parts are connected using a metal corner. As for the upper part, here the connection is made by the same cut, and the edge is sawn along the oblique so that a sliding connection is provided.

IMPORTANT: If you are not comfortable with rigid or semi-rigid freedom, you can install special flexible plates, thereby achieving a fully sliding docking.

ridge knot

As I said earlier, the skate is one of the important components of any truss system where two slopes are joined. As a rule, it is located at the very top of the roof, but there are also such structures where there is more than one skate, for example, mansard roof, there are 3 of them at once.

Rafter legs are almost always created so that they are as close as possible to the ridge element. This will provide better protection against dust and precipitation.

In roofing, there are two types of truss systems. The first is layered, and the second is hanging. If we consider the first, then here the connection occurs by cutting into half a tree. Thanks to this technique, maximum strength is ensured. As for the hanging rafters, here their lower part is joined in pairs. This can be achieved by cutting each beam at a certain angle, which is equal to the roof pitch. After that, they are applied to each other with saw cuts and matched with nails so that each fastener penetrates through the cut into another beam.

Often you can find ridge elements with a perforated body. Small holes do not allow small rodents and birds to enter the attic, and the quality of natural ventilation increases several times.

Complex parts of the hip roof

The hip roof is suitable for almost all types of buildings, so it is best to sort out all the difficulties on it. hallmark hip design is obviously the presence of hips. This truss system boasts the following advantages:

Durability. Due to the correct distribution of the load, the truss elements are subject to less pressure, therefore, they are in relative rest.
Low windage. The material on such a roof is very difficult to pry even the strongest winds.
Resistant to all types of precipitation.
Cost-effective option for large structures.
The optimal angle of inclination allows the use of almost any roofing material.
The hip roof is quite voluminous, so in the attic you can equip living room. To create additional lighting, skylights can be inserted into the slopes, which will also be auditory at the same time.

A rather difficult device can be attributed to the weak side.

The appearance of the roof includes only a few paired figures: a trapezium and a triangle. They are opposite each other, so that the truss system can be considered symmetrical. At the points of contact of these slopes, rafters are arranged. You can attach them to the rest of the system using trusses and a layered structure.

The sloping beams in the lower part are attached to the Mauerlat, or a beam that is placed on inner wall. From above, the support goes to the ridge, so the legs must be adjacent to the ridge run.

Any roof must be laid according to the norms and rules of the construction business. This is the only way to achieve a high-quality and safe design. When working at height, remember safety precautions.

For a durable and reliable roof, it is important to make all the nodes of the truss system with high quality. What this means, we will analyze right now.

The rafter is the skeleton of the roof, on which the inner and outer skin, insulation, waterproofing and other elements are held. Also, very often they are used as the basis for communication. Huge loads fall on the roof and, accordingly, the rafters, which can reach 200 kg / m 2. This is the weight of building materials, snow with foliage and other debris. And what about gusts of wind?

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 necessary equipment. Moreover, all these parameters are strictly individual and depend on a number of factors, ranging from the configuration to the 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 Mauerlat can rightly be called the foundation of the entire system. It is a beam on which the structure is attached. Its main function is to evenly distribute the loads on the walls. But the beam on which the crate is fixed is called the rafter leg. This essential element, which determines the angle of inclination of the slope and general form roofs. Between themselves, the rafter legs fasten the run. It is located both on top and on the side. Depending on this, there are ridge and side runs. At the bottom of the leg are fixed with a puff.

Mauerlat for fastening the truss structure

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

This concept combines a number of structural elements, as they consist of crates, 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 the most suitable would be a segmented or trapezoidal shape. 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 wood. In this case, the beams are mounted by cutting and subsequent fixing with nails, self-tapping screws and other fasteners. However, the use of a tree is not relevant in all cases. So, if the span length exceeds 16 m, then trusses with stretched metal racks will be more suitable, since it will be difficult to ensure reliable fastening of wooden elements in this case. The combined type is also popular, in which both wooden and metal parts are used at the same time.

The ridge is a horizontal rib at the junction of two slopes. There is a layered and truss system of a hanging type. In the first case, the skate is mounted on racks parallel to long walls. It is very important to ensure the maximum adjoining of the rafters to the ridge; for this, appropriate cuts are made. Fixation is done with nails.

Skate at the junction of two slopes

If it's about hanging structure, then the ends of the rafter legs are connected in pairs. To ensure such a pairing, 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 hammered at an angle. Be sure to close the junction metal plate or wooden lining.

Pair connection of rafter legs

When connected with a notch in half a tree, maximum strength is achieved. To do this, at the junction, the rafter legs are connected to the ledge. Then a hole for a 14 mm bolt is drilled. Further fixation is achieved by bolting. 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 truss systems, which you need to dwell on in more detail. There are two technologies for fixing beams to the Mauerlat. Rigid fastenings exclude any shifts, vibrations, turns, torsion and other manipulations. To achieve a similar effect, a drink is made on the leg. Further, the connection is additionally fixed with nails, wire, self-tapping screws and other auxiliary elements. Usually, several nails are hammered at an angle so that they cross inside the Mauerlat. And then another nail is driven vertically.

Washed down on the legs for attachment to the Mauerlat

Sliding mounts are obtained thanks to special fasteners. There is one, two or three degrees of freedom of this conjugation. This connection is great for wooden houses, since rigid fixation during shrinkage can be severely affected. Such a mobile connection can be provided in several ways. The leg rests against the Mauerlat with a hemmed bar or sawn tooth and is rigidly fixed with a metal corner. Thus, the rigidity of the fastening in the horizontal plane is achieved. At the top, the legs are connected by notches, while a bevel is made on a horizontal platform to provide a sliding connection.

Sliding fastening elements

If only one nail is driven in at the place of fixation to the Mauerlat or special flexible plates are used, then the pairing will turn out to be sliding in this part of the truss system.

Now let's focus on the typical nodes of the wooden truss system. The peculiarity of such a 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, they are not afraid strong winds and rainfall, economical. However, they are more technologically complex.

Typical hip roof nodes

This roof consists of two long trapezoidal slopes, while they do not cover the entire area, triangular hips are installed at an angle from the ends of the building. In this case, typical elements appear - additional sloping rafter legs, from which 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.

Roofing from trapezoidal slopes and triangular hips

If the rafters of the slopes rest on the ridge, then oblique legs at the same time, they must be adjacent to the console of the ridge run. It is very important that the console outlet is not less than 100 mm, but not more than 150 mm. Bottom part diagonal rafters is fixed to the Mauerlat or a special beam on the wall of the house. Sometimes a wooden beam is used to make rafter legs, in which case the slanting elements are fixed to a special board (surfboard) fixed on the farm. But the installation to the extreme hanging farm is done by means of a sprengel. At the same time, cuts are made on the beams of the legs at an angle corresponding to the slope of the hip slope.