Rafters or rafters. What are rafters? Main elements of the roof. What materials are needed for the rafter system?

Each roof is based on a large number of beams, rafters, posts and purlins, which are collectively called the rafter system. Over the centuries-old history, many types and methods of its organization have accumulated, and each has its own characteristics in the construction of nodes and cuts. Let's talk in more detail about what the rafter system of a gable roof can be and how the rafters and other elements of the system should be attached.

Design of a gable roof truss system

In cross-section, 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 by a ridge beam (purlin).

Now about the components of the system and their purpose:

• Mauerlat is a beam that connects the roof and walls of a building, serves as a support for rafter legs and other elements of the system.
• Rafter legs - they form the inclined planes of the roof and provide support for the sheathing under the roofing material.
• Ridge purlin (bead or ridge) - combines two roof planes.
• A tie is a transverse part that connects opposite rafter legs. Serves to increase structural rigidity and compensate for thrust loads.
• Lezhny - bars located along the mauerlat. Redistribute the load from the roof.
• Side purlins - support the rafter legs.
• Racks - transfer the load from the purlins to the beams.

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

There are quite a few designs of rafter 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 external walls without intermediate supports (load-bearing walls). For gable roofs, the maximum span is 9 meters. When installing a vertical support and a strut system, it can be increased to 14 meters.

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

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

Gable roof rafter system for small houses

There is a cheap version of the rafter system when it is a triangle (photo below). Such a structure is possible if the distance between the external walls is no more than 6 meters. For such a rafter system, you can not calculate the angle of inclination: the ridge must be raised above the tie 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, either rafters of a larger cross-section are taken or the ridge part is cut in such a way as to partially neutralize them. To give greater rigidity, wooden or metal plates are nailed on both sides at the top, which securely fasten the top of the triangle (also see the picture).

The photo also shows how to extend rafter legs to create a roof overhang. A notch is made, which should extend beyond the line drawn from the inner wall upward. This is necessary to shift the location of the cut and reduce the likelihood of the 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 installing a crossbar - used when. In this case, it serves as the basis for lining the ceiling of the room below. For reliable operation of a system of this type, the crossbar cut must be hingeless (rigid). The best option is in a semi-frying pan (see picture below). Otherwise, the roof will become unstable to loads.

Please note that in this scheme there is a Mauerlat, and the rafter legs must extend beyond the walls to increase the stability of the structure. To secure them and dock them with the Mauerlat, a notch 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 this scheme, almost the entire load falls on the rafters, so they need to be taken with a larger cross-section. Sometimes the raised puff is reinforced with a pendant. This is necessary to prevent it from sagging if it serves as a support for ceiling cladding materials. If the tie 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 belays. In this case, too, boards and nails are enough.

For large houses

If there is 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 the tie in one piece, so it is made from two beams. It is connected by a straight or oblique cut (picture below).

For reliable joining, the connection point is reinforced with a steel plate mounted on bolts. Its dimensions must be larger than the dimensions of the notch - the outer bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the notch.

In order for the circuit to work properly, it is necessary to make the struts correctly. They transfer and distribute part of the load from the rafter legs to the tie and provide structural rigidity. Metal pads are used to strengthen 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 bears a greater load.

With layered rafters

In gable roofs with layered rafters, the ends rest on the walls, and the middle part rests on load-bearing walls or columns. Some schemes push through the walls, some don't. In any case, the presence of a Mauerlat is mandatory.

Non-thrust schemes and notch units

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

The simplest non-thrust rafter system diagram is shown in the photo below. In it, the rafter leg rests on the mauerlat. In this version, it bends without pushing the wall.

Pay attention to the options for attaching the rafter legs to the Mauerlat. In the first, the support area is usually beveled, its length being no more than the 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. The structure results in two pitched roofs, which in the upper part are adjacent (but not connected) to one another.

The option with rafter legs fastened at the ridge part is much easier to assemble. They almost never push against the walls.

To operate this scheme, the rafter legs at the bottom are attached using a movable connection. To secure the rafter leg to the mauerlat, one nail is driven from above or a flexible steel plate is placed from below. See the photo for options for attaching rafter legs to the ridge girder.

If you plan to use heavy roofing material, it is necessary to increase the load-bearing capacity. This is achieved by increasing the cross-section of the rafter system elements and strengthening the ridge assembly. It is shown in the photo below.

Reinforcing the ridge assembly for heavy roofing material or for significant snow loads

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

Options for rafter systems with contractions

Installing contractions increases the reliability of the structure. In order for it to work properly, it needs to be secured to them with nails at the places where it intersects with the drains. The cross-section of the timber for the scrum is 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. See the figure below for attaching the screed to the rafters and ridge girder.

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

Layered rafter systems with struts

In these options, for greater rigidity, rafter legs, also called struts, are added. They are installed at an angle of 45° relative 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 brace is simply placed at the required angle to the beams and nailed on the sides and bottom. An important requirement: the strut must be cut accurately and fit tightly to the posts and rafter leg, eliminating the possibility of it bending.

Systems with rafter legs. The top is a spacer system, the bottom is a non-spacer system. The correct cutting nodes for each are located nearby. Below are possible strut mounting schemes

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°.

Systems with struts are necessary if significant uneven shrinkage of the foundation or walls is possible. Walls can settle differently on wooden houses, and foundations can settle on layered or heaving soils. In all these cases, consider installing rafter systems of this type.

System for houses with two internal load-bearing walls

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

In these systems, a ridge run is not installed: it provides 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-thrust system, the pushing force is neutralized by the tightening. Please note that the tightening is placed under the purlin. Then it works effectively (top diagram in the figure). Stability can be provided by racks, or joints - beams installed diagonally. In the spacer system (in the picture it is below) the crossbar is a crossbar. It is installed above the purlin.

There is a version of the system with racks, but without rafter beams. Then a stand is nailed to each rafter leg, the other end of which rests on the intermediate load-bearing wall.

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

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

To build a reliable roof, there are quite a lot of different materials, but the most important point in the construction of this building element is still its rafter system.

Almost every type of roof has its own peculiarities in the construction of rafters and other floors, but at this stage the construction is based on general provisions and principles that have not changed for many years; they create the margin of reliability that every roof should have. roof.

Let's take a closer look at the main types of rafter systems, as well as the materials from which they are made. We will tell you in detail how one system differs from another when constructing a roof yourself.

To put this as briefly as possible, the roof truss system is a necessary and important element of the building, which consists of a frame with supports on the load-bearing walls of the building. During the construction process, this frame must serve as a reliable basis for all types of materials, such as various types of insulation, waterproofing layers, and roofing materials.

The dimensions and design features of the roof and the entire rafter system depend on several factors:

• the overall size of the entire building;
• correct selection of materials;
• correct and accurate calculation of all future expected loads;
• personal preferences regarding the shape of the roof of the customer himself.
• personal preferences regarding the shape of the roof.

All of the above factors are very important to ensure that the rafter system of the house is selected correctly.

Each of these factors is certainly important for understanding what types of rafter system will be optimal for a particular situation.

What materials are needed for the rafter system?

Wooden rafter systems are perhaps one of the most common, and wood is one of the most reliable materials. This material is very attractive because it is quite easy to install, and the price is much cheaper than many others.

The most common material for arranging rafter systems today is wood. Often, when constructing wooden floors, timber from pine trees -150 millimeters is used. But you can also find boards along with this material, but they are usually sewn together.

Please note that this information primarily concerns construction in the private residential sector.

When multi-storey buildings are erected or in the case of the construction of industrial buildings, then metal rafter systems are used, as well as other materials.

In order for a wooden roof truss system to last as long as possible, it is necessary to treat them in a special way before installation. For this purpose, various compositions are used, here are the main ones:

• Antibacterial compositions - such compositions are aimed at protecting wood from negative rotting processes if the wood is exposed to water (this can happen if the wood is in roofing condensation);
• Fire-retardant compounds - everything is clear from the name; they protect the tree from fires.

There are no problems with processing either of these compounds today, because the market is literally overflowing with various preparations that will successfully protect wooden rafters.

When treating with these compounds, it is best to use an ordinary paint brush, since when using the spraying method, impregnation of the wood may not be sufficient.

Metal rafters- what is their advantage?

When constructing the roofs of industrial buildings, as well as apartment buildings, wooden rafters are not used; the most common option would be a metal rafter system with a technology called light steel frame.

This design of thin-walled galvanized metal profiles for roofs is quite reliable and durable. According to some manufacturers, it can last more than 100 years.

It is possible to note some of its advantages compared to wooden ones. Here are just a few of them:

• The fire safety of this material - this type of roof truss system consists of materials that are not subject to combustion, therefore, fire is excluded. If a fire does start, then this type of truss system will be able to contain the fire for some time and prevent the roof from collapsing;
• There is no need to carry out preventive work with fire-fighting or anti-fungal compounds;
• Long service life - at least 100 years. These structures are not susceptible to fungus, and the zinc coating provides anti-corrosion protection;
• The ability to install such rafters at any time of the year;
• Installation of such metal rafters is quite easy; you can only use a drill and a screwdriver;
• Very low loads on the load-bearing walls of the building, due to the low weight of the structures;
• Good performance for heat retention;

Is it necessary, a metal rafter system?

When constructing multi-apartment high-rise buildings, metal rafters are a good solution. Metal roof rafters can withstand heavy loads, and in this case, almost any material can be used to cover the roof.

But in the construction of private houses, such solutions based on metal structures can be found quite rarely. Still, metal is not a material that retains heat well, rather the opposite.

Therefore, when installing such structures, you need to remember that thermal protection in country and private houses when using metal structures will not be very good. But wooden rafter structures, on the contrary, retain heat very well, so wooden rafters are considered more cost-effective. They significantly reduce energy costs, and this has recently become a rather pressing issue.

Of course, if it is necessary to strengthen wooden structures with metal elements, then this can be done. But it is imperative to lay a layer of insulating material between metal and wooden structures so that negative rotting processes do not begin in the wood due to possible accumulation of condensate.

A solid metal rafter system can also be erected by welding. In this case, there will be no destructive processes, since the entire structure will consist of metal and will not have contact with wooden parts.

When installing metal structures in the roof, it is necessary to insulate it. Since metal structures are “conductors of cold”.

Quite often, metal structures are used for additional supports that are inserted under the ridge girder. After all, it is this part of the house that is subject to maximum loads.

But the main thing, no matter what material the truss structure is made of, the main criterion that it must meet is the reliability of the structure. In other words, all elements in the rafter structure must be secured as rigidly as possible.

Therefore, it is not surprising that most rafter structures are made in the form of a triangle, because this type of fastening, from time immemorial, has been considered the most reliable.

Roof shape and rafters

Depending on the shape of the roof, various types of rafter systems are used, for example:

• so-called hanging rafters;
• layered rafters;
• hip roofs and their rafter system.

Let's look at each of them more closely.

Hanging type of rafter system

The simplest type of rafter structures are hanging rafters. Here are their main features:

Rafters of this type have only two points on which they rest. These support points are the walls of the house itself.

The rafter legs should not rest on the walls by themselves; they should be secured to a special beam - the so-called Mauerlat. Mauerlat is a thick beam, which is fixed to the load-bearing wall with the help of studs or other types of fastenings.

This type of structure is able to withstand large bursting forces and then transfer it to the load-bearing wall.

In order to compensate for the bursting force, a tightening is done. It is designed to connect each rafter pair that is located below. Most often you can find a structure when it is installed at the very bottom. In this case, it can still play the role of covering the entire roof. Of course, no one forbids doing it higher, but in this case it is necessary to remember that the effort on this element increases many times over.

Tightening is an important element in a hanging rafter system, because it not only restrains the bursting force, but also effectively prevents the legs of the rafters from moving apart.

Layered rafters

The system of layered rafters differs from hanging rafters in that this system requires an additional middle wall.

If we consider the structure in more detail, we can highlight the following features.

Layered rafters, or rather their ends, rest on the walls of the house. While the middle part additionally rests on the load-bearing wall, which is located inside the house, or the emphasis is placed on additional supports in the form of pillars.

Another difference is that this type of rafter system works exclusively for bending. But the load that goes into compression does not affect them at all, since it goes into the middle additional support.

Thus, for a layered rafter system, all elements can be made much thinner, and the entire system can be lighter. Of course, this can lead to significant savings in building materials. Which can significantly reduce cash costs.

If a roof is being erected for a building of complex structure, then the types of rafters can be alternated. If there is a middle load-bearing wall (support), layered rafters are installed, and if there is none, hanging rafters are installed.

Rafters for hip roof

A special rafter system is required for hip hip roofs. This is explained by the fact that the geometry of this roof is much more complex, and its rafters are designed to perform different functions.

Let's consider several main types of such rafters:

• Mowing diagonal rafters are used to connect the corners of the house with the ends of the beam (ridge). They form the ribs of the roof being built. These are the longest and strongest of all rafters because they bear almost all the main load.
• Privates The central rafters are designed to connect the sides of the slopes of the ridge beam with the Mauerlat. They must be installed strictly parallel to each other.
• Corner rafters (springs) are much shorter than ordinary rafters. They are used to connect the Mauerlat to the slanted rafters, and not to the ridge. These rafters determine the plane of the slopes of the roof under construction.

The design of rafters for a hip roof, while somewhat complex, still, most importantly, must provide the necessary strength of a hip roof.

Thus, after studying the different types of rafter systems, you must choose the right design that is suitable specifically for your home. A successful roof shape and a strong, reliable rafter system will make your new home not only beautiful and individual, but also safe to live in.

Types of rafters

Rafters can be divided into suspended trusses, suspended trusses and suspended trusses with sleepers.

The ends of the layered rafters rest on the walls of the building, and the middle part (when the span between supports is more than 4.5 m) rests on intermediate supports. Hanging rafters rest only with their ends on the walls of the building. Hanging rafters are installed if the distance between the supports (outer walls) does not exceed 6.5 m. The presence of an additional support allows you to increase the width covered by the rafters to 12 m, and two supports to 15 m.

Design

The end of the rafter leg with a tenon

The end of the tie with a recess for the tenon of the rafter leg

Connecting the upper ends of the rafter legs

The rafters consist of:

• inclined rafter legs,
• vertical racks,
• and inclined struts.

The support of the rafters is made:

• In wooden cobblestone or log buildings on the upper crowns,
• in frame ones - on the top trim.
• in stone houses on the mauerlat, beams with a thickness of 140-160 mm.

The Mauerlat can be located along the entire length of the building or placed only under the rafter leg. If the rafter legs have a small cross-section, they may sag over time. To avoid this, it is necessary to use a special grille consisting of a rack, struts and a crossbar. To make racks and struts, boards 150 mm wide and 25 mm thick or wooden plates obtained from logs, the diameter of which must be at least 130 mm, are used.

To secure the rafter leg, a tie is used that connects the lower ends of the rafter legs of each rafter. When sliding along the tie, the rafter end can damage its integrity. To prevent slipping, it is recommended to engage the rafter leg into the tie with a tooth, a tenon, or both at the same time. In addition, it is advisable to install the rafters at a distance of approximately 300-400 mm from the edge.

filly- a piece of board that extends the lower end of the rafter leg to accommodate the roof overhang or continuous sheathing lying on the eaves.

Narozhnik- an element of the roofing system of a building, a shortened rafter leg that supports the section of the slope between the slanted rafter leg and the roof overhang.

see also

• Filly (design)

Literature

• Shepelev A. M. How to build a rural house. - M.: Rosselkhozizdat, 1976. - P. 184-191. - 352 s. - 150,000 copies.

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See what “Rafters” are in other dictionaries:

Rafters- – load-bearing structures of pitched roofs. Rafters consist of inclined rafter legs, vertical posts and inclined struts. If necessary, the rafters are connected at the bottom with horizontal rafter beams... Builder's Dictionary

Rafters- - load-bearing structure of pitched roofs, consisting of rafter legs, ridge girder, posts and struts, and sometimes tie rods. [STB 1725 2007] Term heading: Wooden products Encyclopedia headings: Abrasive equipment, Abrasives, Highways... Encyclopedia of terms, definitions and explanations of building materials

RAFTER- load-bearing structures supporting the sloping roof. They are usually made from timber, with significant spans from metal... Big Polytechnic Encyclopedia

rafters- Original. Suf. derivative (plural) from the verb stropit “to put rafters”, formed with the help of suf. from the general public. sling “log, roof, ceiling”, with insert t (cf. meet, sharp, etc.), related to other isl. hróf “roof, canopy”,… … Etymological Dictionary of the Russian Language

Mn. A series of logs connected at an angle at the upper ends and resting against the walls of the building at the lower ends, which form the basis of the roof. Ephraim's explanatory dictionary. T. F. Efremova. 2000... Modern explanatory dictionary of the Russian language by Efremova

Rafters, rafters, rafters, rafters, rafters, rafters (Source: “Complete accentuated paradigm according to A. A. Zaliznyak”) ... Forms of words

The main part of a roof that forms its shape. S. are constructed from beams installed obliquely (rafter legs). S. are placed on the upper frame of the wall (mauerlate), it helps to distribute the load evenly over the entire upper plane... ... Agricultural dictionary-reference book

Load-bearing structures of pitched roofs. They consist of inclined RAFTER LEGS, vertical POSTS and inclined STRUTS. If necessary, they are tied at the bottom with horizontal Rafter BEAMs. Source: Dictionary of architectural and construction terms... ... Construction dictionary

Crawling on four rafters. Perm. Crawling on all fours. Mokienko 1986, 94 ... Large dictionary of Russian sayings

Rafters- (rafter legs, hip legs) Inclined logs or beams forming the base of the roof, connected at the top at an angle, and at the bottom resting against walls or mauerlats. (Terms of Russian architectural heritage. Pluzhnikov V.I., 1995) ... Architectural Dictionary

Books

• Catcher in the rye. Higher up are the rafters, the carpenters. Banana fish are good to catch. The man who laughed. Blue period of de Daumier-Smith. Clumsy Paw, J.D. Salinger. The collection of works by J.D. Salinger includes famous works: “The Catcher in the Rye”, “Higher than the Rafters, the Carpenters”, “Good Banana Fish”, “The Man Who Laughed”,…

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The rafter system is a structure that provides the strength of the roof and serves as the basis for laying roofing material. It is shown in the photo.

The roof is a load-bearing structure that performs the following functions:

• gives the building a beautiful appearance;
• takes on external loads;
• protects the attic from the outside world;
• transfers the load from the sheathing and the material on it to the building walls and internal supports.

The main elements of the roof include sheathing, rafters and mauerlat. The supporting structure also includes additional fastening elements - crossbars, racks, rafter struts, spacers, etc. The reliability and strength of the roof is most influenced by the rafter system. Rafters are the main load-bearing part of the roof. The rafter system bears the weight of not only the roof covering, but also the snow cover and wind pressure. It must withstand all these impacts, so the calculation is made taking into account the type of roofing material and the climatic characteristics of the region.

Rafter system design

Connecting the rafters to each other gives rigidity to the roof frame, resulting in a strong rafter structure. The load on the rafters can be quite significant, for example, during strong winds, so the frame is tightly tied to the frame of the building.

In the construction of private houses and cottages, wooden rafter systems are usually used, which are easy to manufacture and install. If mistakes were made during the construction of the walls, these products can be easily processed: shortened, extended, hemmed, etc.

During installation, fasteners of the rafter system are used: bolts, screws, clamps, nails, staples. They are also used to strengthen the load-bearing roof structure. The interconnected elements of the roof create a truss, which is based on triangles, which are the most rigid geometric figure.

When choosing a material for the manufacture of a rafter system, it is necessary to take into account the structural and architectural nuances of the project. Do not forget about antiseptic and fireproof impregnation for them, as this affects the durability of the roof.

The system consists of rafter legs. The rafters are installed at the slope angle of the roof slopes. The lower sections of the rafter legs rest on the external walls using a Mauerlat, which helps to distribute the load evenly. The upper ends of the rafters rest on a beam under the ridge or on intermediate supports. Using a system of racks, the load is transferred to load-bearing internal walls.

Types of rafters

The design transmits a significant horizontal bursting force to the walls. In order to reduce the load, a stretcher is used to connect the rafter legs. It is done either at the base of the rafters or at a greater height. The tension at the base of the rafters is also a floor beam - this is important when creating attic roofs. When increasing the height of the brace, it is necessary to increase its power and ensure that it is securely attached to the rafters.

Part layered rafters includes: rafter leg, mauerlat, headstock, strut, tightening. This type of rafters is installed in buildings that have a middle load-bearing wall or intermediate supports in the form of pillars. Elements of this design work only in bending, performing the function of headstocks. The weight of the layered rafter system is less, and less materials are also required, so it is cheaper than a hanging system.

Installation of a layered system is done if the supports are no more than 6.5 meters apart from each other. If there is an additional support, the rafters sometimes cover a width of 12 meters, and if there are two supports, up to 15 meters.

Rafter legs most often rest not on the walls of the building, but on a special beam - a mauerlat. This element can be located along the entire length of the house or placed only under the rafters. If the structures are wooden, for the mauerlat they take a log or timber, which is the upper crown of the log house.

When laying brick walls, the mauerlat is a timber installed flush with the inner surface of the walls, fenced from the outside by a masonry protrusion. A layer of waterproofing is laid between this element and the brick - for example, you can put roofing felt in two layers.

If the width of the rafters is small, they may sag over time. To prevent this from happening, use a grid consisting of a rack, a crossbar and struts. At the top of the structure, a purlin is laid that connects the rafters or trusses. This is done regardless of the type of roof. Subsequently, the roof ridge is made on this run. In places where there are no load-bearing walls, the heels of the rafters rest against the side purlins - longitudinal beams of considerable power. The dimensions of these parts depend on the expected load.

When building private houses, rafters made of logs are used - they are lighter. Metal rafters are used to create roofs on multi-story residential buildings and industrial buildings.

Installation of rafter systems

The slope angles of the slopes are selected based on the type of building and the purpose of the attic space. The amount of slope is also influenced by the material chosen to create the roofing.

If roll products are to be laid, the angle of inclination should be 8-18 degrees. For tiles, the required angle is 30-60 degrees, for roofing steel or asbestos cement sheets - 14-60 degrees.

The installation of the rafter system begins after the construction of the load-bearing walls of the house (more details: ""). The design of the rafters of a log house differs significantly from systems for houses made of foamed aerated concrete, brick, frame wooden or panel houses. The differences are significant even with the same shape, type and type of roof. As for how to treat the rafter system, it is necessary to use antiseptic and fire-fighting agents so that the roof lasts a long time.

The main elements of the supporting structure are the sheathing. The roof is the outer part of the roof, which is laid on a supporting structure consisting of sheathing and rafters.

To produce rafters, material of a certain size is taken. Thus, the thickness of the rafters (section) is most often 150x50 and 200x50 millimeters. For lathing, beams and boards measuring 50x50 and 150x25 millimeters are usually used. The distance between the rafter legs is on average 90 centimeters. If the roof slope is more than 45 degrees, this step is increased to 100-130 centimeters, and if a huge amount of snow falls in the region, then it is reduced to 60-80 centimeters.

To make more accurate calculations regarding the gap between the building legs, you need to take into account their cross-section, the step between the supports (struts, ridge run, uprights), and the type of roofing material.

The floating rafter system is attached using special brackets, allowing the rafters to “sit down” along with the shrinkage of the gables and not hang over the ridge log.

In mountainous areas, the chalet rafter system is popular (more details: ""). A feature of this design is the significant protrusion of the roof beyond the load-bearing walls. Sometimes such a protrusion reaches two to three meters, and the angle of the roof slope is small. Snow does not linger on such a roof, so it lasts a long time. But the best option is a roof overhang of 1-1.5 meters (read also: “Characteristics and design of roofs: rafter systems”).

The installation of the rafter system must be carried out in strict compliance with all requirements. If you have no experience in construction, it is better to entrust the construction of the roof to specialists, since this is not an easy task, and the slightest mistakes can lead to its collapse.