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Roof installation is a complex multi-step process. To independently assemble and install a rafter system, you need to carefully study the methods of connecting elements, calculate the length of the rafters and the slope angle, and select the appropriate materials. If you don’t have the necessary experience, take on complex designs not worth it. The best option for a residential building small sizes– do-it-yourself gable roof.

A standard roof of this type consists of the following elements:

Mauerlat is a timber laid on top of the walls along the perimeter of the building. It is secured using threaded steel rods embedded in the wall or anchor bolts. The timber must be made of coniferous wood and have a square section of 100x100 mm or 150x150 mm. The Mauerlat takes on the load from the rafters and transfers it to the external walls.

Rafter legs- these are long boards with a cross section of 50x150 mm or 100x150 mm. They are attached to each other at an angle and give the roof a triangular shape. The structure of their two rafter legs is called a truss. The number of trusses depends on the length of the house and the type of roofing. Minimum distance between them is 60 cm, the maximum is 120 cm. When calculating the pitch of the rafter legs, you should take into account not only the weight of the covering, but also the wind load, as well as the amount of snow in winter.

It is located at the highest point of the roof and most often represents a longitudinal beam connecting both slopes. The beam is supported from below by vertical posts, and the ends of the rafters are attached to the sides. Sometimes the ridge consists of two boards that are nailed to the top of the rafters on both sides and connected at a certain angle.

Racks are vertical beams with a cross section of 100x100 mm, located inside each truss and used to transfer the load from the ridge run to the load-bearing walls inside the house.

The struts are made from scraps of timber and installed at an angle between the posts and rafters. Strengthened with struts side faces trusses, the load-bearing capacity of the structure increases.

Tie - a beam connecting the lower parts of the rafters, the base of the truss triangle. Together with the struts, such a beam serves to strengthen the truss and increase its resistance to loads.

A log is a long beam with a cross section of 100x100 mm, laid along the central load-bearing wall, on which the vertical posts rest. Lezhen is used when installing layered rafters when the run between the outer walls is more than 10 m.

The sheathing consists of boards or timber placed on the rafters. The sheathing can be continuous or with gaps, depending on the type of roof. It is always attached perpendicular to the direction of the rafters, most often horizontally.

If there is no more than 10 m between the external walls and there is no load-bearing wall in the middle, arrange hanging rafter system. With this system, the upper ends of adjacent rafters are sawn at an angle and connected to each other using nails, excluding the installation of racks and ridge beams. The lower ends of the rafter legs rest on the external walls. Due to the absence of racks, the attic space can be used for arranging an attic. Very often, the function of tightening is performed by floor beams. To strengthen the structure, it is recommended to install the top tie at a distance of 50 cm from the ridge.

If there is a central supporting wall, the arrangement is more justified layered rafter system. A bench is laid on the wall, support posts are attached to it, and nailed to the posts ridge beam. This installation method is quite economical and easier to implement. If the ceilings are interior spaces are designed on different levels, racks are replaced brick wall, dividing the attic into two halves.

The roof installation process includes several stages: attaching the Mauerlat to the walls, assembling the trusses, installing the rafters on the floors, installing the ridge, and attaching the sheathing. All wooden elements Before assembly begins, they are thoroughly treated with any antiseptic composition and dried in air.

To work you will need:

• timber 100x10 mm and 150x150 mm;
• boards 50x150 mm;
• boards 30 mm thick for lathing;
• roofing felt;
• metal studs;
• jigsaw and hacksaw;
• hammer;
• nails and screws;
• square and building level.

IN wooden houses The functions of the mauerlat are performed by the logs of the last row, which significantly simplifies the work process. To install the rafters, just cut inside log grooves of the appropriate size.

IN brick houses or buildings made of blocks, installation of the Mauerlat occurs as follows:

The mauerlat bars must form a regular rectangle and be in the same horizontal plane. This will facilitate further installation of the roof and provide the structure with the necessary stability. Finally, markings are made on the beams for the rafters and grooves are cut along the thickness of the beam.

When choosing a hanging rafter system, it is necessary to assemble the trusses on the ground and then install them above the floors. First you need to draw up a drawing and calculate the length of the rafter legs and the angle of their connection. Typically, the roof slope is 35-40 degrees, but in open, heavily blown areas it is reduced to 15-20 degrees. To find out at what angle to connect the rafters, you should multiply the angle of the roof by 2.

Knowing the length of the run between external walls and the angle of connection of the rafters, you can calculate the length of the rafter legs. Most often it is 4-6 m, taking into account the eaves overhang 50-60 cm wide.

The upper ends of the rafters can be fastened in several ways: overlapping, end-to-end and “into the paw”, that is, with grooves cut out. Metal plates or bolts are used for fixation. Next, the lower and upper ties are installed, and then the finished trusses are lifted up and installed above the floors.

The outer trusses are attached first: using a plumb line, the rafters are aligned vertically, the length of the overhang is adjusted and attached to the mauerlat with bolts or steel plates. To prevent the truss from moving during installation, it is reinforced with temporary beams made of timber. After installing the outer rafters, the rest are set, keeping the same distance between them. When all the trusses are secured, take a board with a cross-section of 50x150 mm, the length of which is 20-30 cm longer than the length of the cornice, and nail it along the upper edge of the slope. The same is done on the other side of the roof.

The first option: a rectangular groove is cut out on the rafter leg at the point where it contacts the mauerlat, 1/3 of the width of the beam. Stepping back 15 cm from the top of the box, a steel spike is driven into the wall. The rafter is leveled, the grooves are aligned, then a wire clamp is placed on top and the beam is pulled close to the wall. The ends of the wire are securely fastened to the crutch. The lower edges of the rafters are carefully cut off circular saw, leaving an overhang of 50 cm.

Second option: the upper rows of walls are laid out with a stepped cornice of bricks, and the mauerlat is placed flush with the inner surface of the wall and a groove is cut out in it for the rafter. The edge of the rafter leg is cut to the level top corner cornice. This method is simpler than others, but the overhang is too narrow.

Third option: ceiling beams extend beyond the edge outer wall by 40-50 cm, and roof trusses installed on beams. The ends of the rafter legs are cut at an angle and rest against the beams, secured with metal plates and bolts. This method allows you to slightly increase the width of the attic space.

Installation of layered rafters

Figure 1 shows the cutting of rafter struts into a beam laid on intermediate supports, and Fig. 2 - resting the rafter leg on the mauerlat

The procedure for installing a layered rafter system:

When the main elements are fixed, the surface of the rafters is treated with fire retardants. Now you can start making the sheathing.

For the sheathing, timber 50x50 mm is suitable, as well as boards 3-4 cm thick and 12 cm wide. Waterproofing material is usually laid under the sheathing to protect the rafter system from getting wet. The waterproofing film is laid in horizontal strips from the eaves to the roof ridge. The material is spread with an overlap of 10-15 cm, after which the joints are secured with tape. The lower edges of the film should completely cover the ends of the rafters.

Between the boards and the film it is necessary to leave ventilation gap, so first they stuff it onto the film wooden slats 3-4 cm thick, placing them along the rafters.

The next stage is covering the rafter system with boards; they are stuffed perpendicular to the slats, starting from the roof eaves. The pitch of the sheathing is influenced not only by the type of roofing, but also by the angle of inclination of the slopes: the greater the angle, the greater the distance between the boards.

After completing the installation of the sheathing, they begin cladding the gables and overhangs. You can cover the gables with boards, plastic panels, clapboard, waterproof plywood or corrugated sheeting - it all depends on financial capabilities and personal preferences. The sheathing is attached to the side of the rafters; nails or screws are used as fasteners. Overhangs are also hemmed various materials– from wood to siding.

Video - DIY gable roof

Any rafter system is formed from numerous rafters, for the creation of which timber or boards are used. Most often, boards are chosen due to their affordable cost, but their strength is considered not too high compared to timber.

Important! The durability of the roof and the safety of living in the house depend on the quality of the selected lumber.

Requirements for rafter boards

Roof rafters can withstand significant impacts from snow, wind and roofing, so in the process of their creation certain rules must be taken into account that they must comply with.

Important! During the formation of rafters, not only right choice their size and cross-section, but also the material used to create them.

It is considered optimal to choose timber for rafters , but this material is expensive, so boards are often purchased to reduce costs. Only high-quality wood is selected, and often the choice falls on pine needles or larch.

When searching for boards used to create rafters, the basic requirements for them are taken into account:

Boards are purchased only from trusted sellers who provide buyers with information about the product. To do this, there must be special accompanying documentation, and it contains information:

• type of wood used to make boards;
• name and number of the product standard;
• the name of the production organization involved in its production;
• number of units in one package;
• date of release of boards;
• dimensions of lumber, as well as its moisture content.

Important! Wood is a natural material, therefore various biological influences lead to its destruction, so it is important to choose the boards wisely, as well as protect them with special protective compounds.

Rafter boards must be treated before use different compositions:

• treatment with high-quality antiseptics that will prevent the material from rotting;
• impregnation with fire retardants that protect wood from fire;
• treatment with pest and insect repellents.

Only with the right choice of boards and after them high-quality processing It is possible to make rafters that are not only of high quality, but also resistant to various influences.

What size should the rafters be?

After being selected optimal board for rafters, you can begin to create a special drawing and diagram of the future rafter system. To do this, determine the cross-section, length, width and other parameters of the rafters, which, after manufacturing, will be connected to each other in the correct sequence.

The size of the rafters can vary significantly, since this parameter is influenced by many factors. These include the dimensions of the house and roof, the chosen design of the rafter system, possible loads from wind and other similar influences. It would be best to use the following recommendations:

• the minimum size is 50x150 mm;
• if significant spans are created, then the size is selected 150x150 or 250x100;
• Often larger rafters are used if it is planned to build a large trade pavilion or other large structure.

Important! To accurately know the optimal dimensions of the rafters for the roof, you need to correctly calculate this indicator.

For the calculation, it is important to determine what load will affect the roof as much as possible, which allows you to select the cross-section and other parameters of the rafters. Additionally, it is possible to take advantage of special standard values, but they do not take into account certain climatic conditions of different regions, so experts prefer to carry out correct calculations, materials on the topic: , .

Correct determination of rafter dimensions

When determining optimal sizes rafters, it is important to consider how thick the board used to create the rafters should be.

Important! The thickness of the board has a direct impact on the strength of the products created from it.

It is advisable to use a board for these purposes, the thickness of which varies from 4 to 6 cm. If the rafter system is being erected in small buildings intended for economic use, then to reduce costs it is allowed to use boards 3.5 cm thick. For a residential building, it is recommended to choose products whose thickness will not be less than 5 cm.

When choosing the width of the board, you must take into account the length of the opening that overlaps the rafters. The longer the rafters should be, the wider the board used to create them:

• if the length of the rafters is approximately 6 m, then it is advisable to use a board whose width is approximately 15 cm;
• if the length of the legs exceeds 6 m, then the width of the board should be 18 cm;
• if you want to get an even longer rafter leg, then building up the elements is used, and the places where there is an overlap should be located next to the ridge part of the roof.

The cross section of the rafters is calculated depending on the specific optimal distance between them, and the length of the elements is also taken into account. While working, you need to decide which permanent loads will affect the roof from wind and snow. The mass of the created truss structure, the angle of inclination of the slope, as well as the length of the opening that needs to be covered. When calculating, it is additionally taken into account how wide the structure is.

Important! To facilitate calculations, it is recommended to use special computer programs, freely available on the Internet, and with their help not only provides fast receipt result, but also guarantees the accuracy of the values.

After determining the cross-section of the rafters, you need to decide at what distance from each other they will be installed. directly related to their cross-section, so if these parameters are not correctly determined, this may negatively affect the reliability and durability of the roof.

Important! It is allowed to reduce the cross-section of the rafters if special struts are used.

Basic rules for choosing boards

The rafter board must meet numerous requirements and conditions described above. To really choose quality material, it is recommended to use certain expert advice. These include:

Important! If material is purchased from high rate humidity, then it is not allowed to use it for the construction of a rafter system, since it will be fragile, and there is also a danger for living in a house with such a roof, since after a short period of time the geometry of the structure will be disrupted.

If several unsuitable elements are found in one batch of boards, it is not recommended to use them to create important parts of the roof, so they are used for additional elements.

Making the roof of a house is an important and responsible task. The integrity of the structure and the peace of the residents will directly depend on the quality of the upper structure. Before starting work, it is necessary to select the right boards for the rafters and other roof parts, perform their high-quality pre-treatment and correctly connect them, preparing them for laying the roofing material.

Types of roofs

Currently for residential buildings and outbuildings used about ten various types roofs Some of them are more familiar to us, others are very rare. The main design options are:

Pitched roofs made using straight rafter systems:

• single-pitched;
• gable;
• hipped - hip and half-hip (with a ridge) and hipped (without a ridge);
• multi-tongs:
• conical

Pitched roofs with curved rafters:

• semicircular;
• hemispherical.

Almost all types of roofs are based on special parts that provide the roof with the necessary strength and give it the desired shape. We are talking about rafters.

Requirements for the quality of rafters

For the manufacture of rafters they use edged boards different sections. The most common parts are with a cross section of 50x150 or 50x200. Square or rectangular beams are not used, since they cannot provide the necessary strength of the structure or will significantly make it heavier. Always install rafters on edge with your own hands. In this direction, the parts are more durable and not subject to bending.

Installation of the rafter system of an outbuilding

It is better to choose boards for work coniferous species. This is due to several of their features:

• the presence of resin prevents the formation of rot in the material;
• such parts have a relatively low weight, unlike, for example, birch boards of the same section;
• Coniferous material is more affordable, and it is much easier to find it at sawmills.

In addition, be sure to pay attention to elements in the wood such as knots. The presence of rotten falling out elements, which could lead to a decrease in the strength of the rafter leg in the future, is not allowed.

Preparing rafter system parts for installation

Before you begin installing the roof truss system with your own hands, we recommend that you carefully treat the surface of all wood parts used in the work.

Preliminarily inspect the purchased lumber and select the best quality. Boards with falling knots can be used in pieces, for example, when lengthening or for making racks (headstocks), struts, crossbars and other roofing parts.

After selecting a sufficient amount of lumber, it is treated with special protective compounds that prevent rotting and burning.

• You can apply fire retardants and antiseptics with your own hands in the following ways:
• by immersion;
• brush or paint roller;

spraying. for various purposes in one container.

Choosing the optimal rafter system

Having selected high-quality 50x150 boards and processed them with our own hands, we proceed to the installation of the rafter system. Before starting work on the perimeter of walls made of bricks or blocks, it is necessary to lay a mauerlat - a beam that will serve as a support for lower parts rafter legs.

Fasten it with threaded rods, recessed into the wall or steel wire laid in the masonry seam. In buildings made of timber or logs, the role of the mauerlat is played by the upper crowns of the log house.

Depending on the size of the span between the walls of the house, we choose the option for installing rafters. There are systems with hanging rafters or layered ones, resting on an intermediate load-bearing wall.

Roof options: 1) With hanging rafters. 2) With layered rafters

The first type of structure has a horizontal transverse beam - a tie. In the second, this element is missing. For support, the ridge beam rests in several places on the intermediate wall of the house. This is not entirely convenient in the case of making an exploitable under-roof space - an attic, but it is optimal for large flights between the walls.

Determining the number of trusses

To determine the amount of lumber required for the manufacture of rafters, for example, 50x150 boards, it is necessary to calculate the required number of rafter trusses - pairs of rafters connected at the required angle. On average, the span between them is 0.9-1.2 meters or slightly less. The determining criterion is the roofing material to be used.

Thus, for ondulin, the manufacturer recommends a rafter installation pitch of 0.6-0.9 meters, for metal tiles - one of the most common materials in last years– 0.65-0.95 meters. Great importance When choosing the inter-rafter distance, the slope angle of the slopes also plays a role, which depends on the snow and wind load in each specific area.

Having determined the step size, we divide the length of the walls by this indicator and add one to take into account the installation of gable trusses. Let's get the number of rafter pairs. By multiplying this number by two we determine the required number of rafters. We calculate the length of the boards using the Pythagorean theorem, knowing the same slope angle and the span of the walls.

We install the rafter system - we assemble the trusses

Having decided on the number and size of the rafters, you can begin assembling the roof truss system with your own hands. As a rule, they try to install pre-assembled trusses. They can be made both on the attic floor of the house and on the ground and lifted ready-made.

In any case, several templates will help make your work much easier.

The first of them is a rafter of the required length with the ends sawn at the required angle. If necessary, the edges can be cut not in a straight line, but with ledges to facilitate the installation of parts. For example, if the rafters are supported by timber, fastening can be done with steel angles, perforated steel tape or nails. In all cases, a figured cut will increase the quality of installation.

The second template is a sheet of plywood with stops nailed at the required angle, into which the upper ends of the rafters are inserted and connected by crossbars - transverse boards with a section of 50x150, providing the necessary rigidity of the rafter pairs. If free space allows, you can use one self-assembled truss as a template.

Installing farms

Trusses prepared with your own hands are lifted up. It is convenient to start installation with the outer pairs, called pediment ones. They are installed vertically, controlling the position using a plumb line or a board nailed to the wall of the house, and fix the position using additional slopes. The lower ends of the truss rest on the mauerlat beam or on the crowns of the log house. They are nailed to them with No. 100 nails.

Methods for attaching a rafter leg to a mauerlat

Having fixed the outermost truss, the rest are fastened, observing the span between them. To control this value, you can pre-cut spacers from a 50x150 board with your own hands and not measure the distance for each pair. After installation, the corners of the trusses are additionally connected with a ridge beam or board. Additionally, lathing will help secure the rafters.

Are you already at the finish line in building your dream home, and it’s time to understand the intricacies of the rafter system? Let's just say: pleasant worries await you: calculating the angle, weight and safety factor of the rafters, an agreement with a familiar craftsman or company, or preparing all the necessary tools for independent carpentry work.

And so that tomorrow all these worries do not become a headache and you do not worry about whether this or that knot is being done correctly, we have prepared this article for you. So, let's figure out how to make high-quality rafters for gable roof with your own hands so that it is no worse than purchased ones.

• Short production times.
• Technological precision of all details.
• Identical, already adjusted dimensions of all structural elements.

But then be prepared for the following disadvantages:

• High cost (at least twice as much as if you planed the rafters yourself).
• Delay in delivery (especially during the season).
• Using low-quality or under-dried wood (and then the roof will “sink”).

So convenience or quality? If this is not your first time carving or planing something out of wood, feel free to take on making rafters! Here's what it all looks like in real life:

Rafters in the construction world on in simple language It is customary to divide the main ones, i.e. load-bearing ones, on which the roof is supported, and auxiliary ones, which are located inside the roof and serve as support for hemming the ceiling and walls of the attic (if one is planned). The strength and reliability of the future roof depends on how accurately and correctly you calculate the rafter system in advance.

The rafter system of any gable roof itself consists of the following basic elements that you need to make:

• Mauerlat.
• Vertical racks.
• Crossbars.
• Rafter legs.
• Spacers.
• Ridge run.

Complex roofing structures with multiple elements it is better to entrust the calculation to a professional, but with a small roof of a private house you can handle it. To do this, you will need these simple formulas that will help you find out how thick the rafters should be, with what slope and what span:

How to draw up a project for a future roof?

Used in roof construction Golden Rule- measure seven times, and cut only once. And first of all, it is important for you to understand that each rafter leg has its own individual location. Therefore, first, be sure to draw up a detailed project, and preferably in a special program. Only after this, using your 3D model of the future roof, mark exactly where and what kind of connections the rafters will have with the Mauerlat and with each other.

It is important to determine as accurately as possible the angle of inclination of the rafters and at what angle they need to be cut. And don’t worry about how to make all these rafters for a gable roof yourself: all you need is a regular machine.

Determining the angle of inclination of the roof: calculating the loads

The angle of inclination of a gable roof is made from 5° to 90°. But the most proven and standard option is 35°-40°, where loads are distributed most rationally and building materials are consumed.

Straight slopes are built when in the future there will be only a non-residential attic under the roof, the main function of which is ventilation and regulation of heat exchange. But when the under-roof space is planned to be residential, attic, they initially plan a so-called sloping gable roof. Its difference is that the slopes in the middle have a kind of kink, which changes their angle to a steeper one. This design is quite suitable both for arranging an attic and for protecting the entire house from bad weather.

Please note that most roofing materials are only suitable for pitches greater than 45°.

Constant and variable roof loads

The same loads determine what rafter pitch you need for your gable roof. This table will help you choose the right section of rafter legs:

Indicators of rafters for deflection

Even strong-looking rafters may not be suitable for constructing the roof of a residential building due to the fact that they have insufficient deflection properties. There are separate paragraphs in the SNiP section called “Loads and Impacts”.

And the easiest way to increase the deflection strength of rafters is to make the cross-section larger. It’s a little more difficult to strengthen it with a special beam, bringing its edge to the strut.

Reinforcing elements for rafters

The more racks, struts and contractions, the more durability and stability the entire rafter system has.

If you have any suspicions or even an exact estimate that simple design the roof will not withstand future loads, make one for it additional elements gain. Such prevention will never hurt, but it will save you from many problems. Note that it is especially offensive when the garage roof falls in - right on top of the car. And such problems are not a joy for a residential building.

The rigidity of the rafter structure is enhanced by struts, additional purlins and support posts. The braces are designed to reduce the span of the rafter legs. Their angle of inclination to the horizontal is usually at least 45°.

A purlin is a horizontal beam, which is located parallel to the ridge and is fixed to vertical racks. More details in the video:

Determining the type of roof: cold or warm?

And now about the concept of the attic. If you are building a roof for a bathhouse or a small utility room, it can be done using the most simplified technology - install rafters, connect them at the ridge and cover them with sheets of roofing felt. But for the roof of a residential building, where ventilation is important, this principle cannot be used. There will already be at least three levels:

1. The upper or first level of the rafters is about 200 mm.
2. The average one is always equal in height to the auxiliary rafters.
3. The third one is already on the edge of the wall.

This makes it convenient to lay insulation, because the roof of a residential building is characterized by the fact that heat rises upward even in the absence of thermal insulation roof covering constantly heats up.

The result: in winter, the snow melts and slides down, freezing and accumulating even more at the cold cornice. This causes a lot of problems: long dangerous icicles, and clogged drainage system, and the gradual destruction of the entire roof. Decide for yourself!

Determine the type of rafter system: layered or hanging?

So, now is the time to think about the support bases for future rafters, which also need to be prepared in advance and on which many parameters of the roof itself will depend. Thus, rafters are divided into layered, hanging and hybrid.

Hanging rafters are usually the lot of small and light roofs, the distance between the supports does not exceed 6 meters. But in buildings with a load-bearing middle wall or additional supports, layered rafters are installed to strengthen the roof. Or like this combined option:

Another difference is that the hanging rafter system forces the Mauerlat to work in compression, while the layered rafter system works for shear. But the main task of both layers and hanging rafters– transfer the loads of the entire roof to the walls and foundation as evenly as possible.

Selecting material for rafters

So, if you have decided on future loads, it’s time to choose suitable material. The following are usually used for making rafters:

• Wood. Solid wood, boards or laminated veneer lumber.
• Lightweight metallic profile. We are talking about galvanized steel profiles.
• Black metal. These are I-beams and steel channels.
• Heavy reinforced concrete structures for industrial construction.

Dry board: economical option

If large loads are not expected on the rafter system, then make the rafters from dry planed boards with a small cross-section. But if knee-deep snow is not uncommon in your area and the roofing material is not light, then some of constituent elements you will have to make glued ones. That's the whole difference.

It is most convenient to make elongated side rafters and diagonal rafter legs from the board. So, a 40 mm thick board, which is often used for outbuildings, is not suitable for a roof. At least 50 mm! Moreover, the longer the rafter leg is planned, the wider the board itself should be. So, rafters 6 meters long will have to be made from boards 150 mm wide, and even longer ones - from boards 180 mm wide.

For the roof frame house this is truly one of the most best options!

And also rafters made from boards are the most economical, and at the same time they are almost as strong as lumber. It is only important to choose the right section and use high-quality material. Therefore, when purchasing material, be sure to take with you special device to measure wood moisture content and use it. There is nothing worse than damp rafters. And it’s not just a matter of future mold: such a roof will begin to warp and warp, because this material changes its shape when it dries. The fastenings at the rafters will fly off and even the covering of your gable roof will bounce off in places. In a word, there will be no problems!

But it is most convenient to splice rafters along the length from a regular board:

Durable metal: resists moisture

And, you will be interested to know that rafters can be made not only from wood! Thus, iron rafter systems, which were once used exclusively for industrial construction, are regaining their former popularity today. And, let us note, this roofing material has many advantages, the most valuable of which is the complete absence of fungus from dampness. After all, the space under the roof most often “pleases” with random leaks.

And the work itself with such rafters during installation is no more difficult than with wooden ones - see for yourself:

Beams: the benefits of high-quality wood

The beam is more durable, but the disadvantage is that it has a lot of weight and you have to make cuts in the fastening areas. For the log this is not only a problem, but also some loss bearing capacity such a rafter leg. But so far this material is the most popular for making rafters.

Most suitable for the manufacture of rafters is lumber that meets the requirements of GOST 8486-86 or 2695-83. And this:

• Humidity no more than 18%, measured with a moisture meter.
• Cracks that are not through and do not exceed half the length of the board.
• For each linear meter– no more than three knots, and each of them is no more than 30 mm in diameter.

Therefore, when purchasing wood for rafters, be sure to check the documents from the seller, which indicate the quality of the product.

The type of wood is also important. The fewer knots and cracks there are on the beams, the better. Some varieties also boast good moisture resistance and resistance to rot and pests. For the roof this is what you need. Therefore, we recommend making rafters from coniferous wood, which is rich in resin, and resin is a natural barrier against rotting. But special processing still needed.

And also take into account this fact: when manufacturing a rafter system, you need to purchase 5-7% more material than necessary, because it will not always be possible to make an ideal rafter cut or notch of the required depth. There will still be overspending, so stock up on it in advance so that you have wood of the same moisture content and properties for the entire rafter system.

Otherwise, if any individual elements you had to purchase roofs separately; they may take longer to dry (wood always dries), or vice versa. The distortions can be considerable, i.e. the entire roof frame will be constantly exposed to different physical forces of tension and pressure. Any experienced roofer will tell you how bad this is and what it entails. Therefore, take more material for making rafters than you plan. If everything goes smoothly, there will be something to use to make the first bench in front of the new house.

Treatment with antiseptics and propylents

And at this stage it is already important to protect the future rafter system from biological destruction. You don’t want your roof to collapse after a couple of years of use, do you? Therefore, be sure to treat the wood for the rafters with fire and bioprotection.

The rafters are usually impregnated with an antiseptic and then treated with a fire retardant on top. You can also alternate this processing several times. If you use universal impregnation, be aware that it usually contains products with different service life. For example, fire protection will end before bio.

But the choice of means for processing today is huge. These are also universal protective equipment, and a variety of fire retardants and antiseptics. It’s easy to decide: if you are building in a fairly hot and dry area, first of all use fireproofing impregnations, which deprive the wood of its natural flammability. And if your house is located where the air humidity is almost high all year round– protect from rotting.

You can, of course, use both drugs - but just do not mix, otherwise the whole material will deteriorate. You just need to choose one product as an impregnation, and the second as a protective surface layer. Just try to dilute everything in the concentration indicated by the manufacturer. But do not treat frozen or damp wood: its fibers simply won’t absorb anything.

Video tip on the topic of processing rafters:

Note that a brush or spray when processing rafters gives little result - complete immersion and subsequent drying are much better. Just use a regular container, cover it with film from the inside and make a “bathtub” for future rafters. Moreover, it is advisable to do all this on the ground, as soon as you bring the material to the site, because in the finished rafter system it will be difficult to reach the internal elements of the connections. And they are the most defenseless in terms of moisture penetration. After processing, dry the parts so that all sides are ventilated for at least 24 hours.

Do not forget also that wood, like any natural material, subject to biological destruction. Therefore, in addition to fire-bio-protection, it is important to consider waterproofing in all places where the rafter system adjoins the brick walls of the house, if any.

Making the correct cuts on the rafters

Now let's move on to practice. First of all, you definitely need to make a convenient template according to which you will make even, identical rafters:

And follow these instructions:

You will have to tinker with the rigid mount:

If we are talking about moving units, then follow this principle:

In practice, everything is actually simple:

As you can see, the eyes are afraid, but the hands do!

How to assemble a rafter system?

Finally, the rafters are ready, and you can start installing them.

Build on the ground or on the roof?

So, in reality everything is quite simple and somewhat similar to the children's designer. The easiest and most convenient way is to make trusses directly on the ground, and only then raise them. It is a little more difficult to assemble the rafters directly on the roof, but it is easier to lift them there. This is where you start: if you have the opportunity (a crane, for example) to drag 200 kg of one truss onto the roof - drag it, if not - lift each individual rafter 50 kg using improvised means and do the assembly on the spot.

So, first of all, for convenience, make a template according to which you will assemble the roof trusses, and another template for mounting cuts on the rafters (use plywood). All you have to do is cut out mounting cuts on the rafters, attaching a template, and connect them together at a certain angle. This triangle is called a roof truss.

Attention to strength - rules for increasing length

If the thickness or length of the board is not enough to make a normal rafter leg, extend the rafters. And there are several ways:

1. Connect the boards together by folding them with their wide sides and stitching them with nails.
2. Lay the boards half the length, resulting in a particularly strong rafter leg that can withstand considerable loads.
3. Make an oblique cut at the ends to create a vertical anti-slip stop, and connect with a bolt.
4. Lay two overlapping boards a meter long, connecting the rafters with pins or nails.

Also keep in mind when calculating that the roof ridge accounts for about 50% of the load of the entire rafter system. Therefore, always make a ridge beam so that its safety margin is at least 25% greater than originally calculated.

And the most vulnerable parts of the rafter structures are the lower ones, those that rest on the Mauerlat.

Preparing roof trusses

Fasten rafters needed using:

• External straight bracket.
• Metal corner plate.
• Internal metal rod.

You can also connect such rafters with studs - this will even be stronger. To do this, instead of making a cut, we now make a cut into half the tree and connect the rafters with a ledge. Next, drill a hole for a 12-14 mm stud and secure it with nuts and wide washers.

Let's start with a review of proven old-fashioned methods:

When assembling a hanging type truss, you need to connect the upper ends of the rafter legs. To do this, cut the end of each at exactly the same angle at which you are making the roof, connect the beams with cut planes and secure with two nails. Cover the joint with a wooden cover or metal plate.

Another useful master class:

Lifting and installation of finished trusses

Already on the roof, first of all, you need to start by installing those rafters that form the two outer trusses of the gable roof (they are also called gable). To further secure them, install temporary struts. Next, stretch a strong cord between the outermost peaks of the trusses, which will become a level for the intermediate rafters.

Now we lift and place all the remaining trusses at a distance of at least 0.6 meters from each other. Again, if some of your structures turn out to be quite cumbersome, support them with the same temporary supports.

The rest is a matter of technique:

The roof frame must be reliable and durable. But without proper calculations this is difficult to achieve. In the process of carrying out calculations, they determine at what distance to place the rafters on the roof.

What can result from an incorrect or inaccurate calculation of the loads to which the truss structure will be subjected? To the very negative consequences, ranging from deformation of the rafter legs and damage to the roof covering and ending with the collapse of the base of the roof frame. Therefore, when designing buildings, the list of mandatory calculations contains data on what the distance between the roof rafters should be. There is a certain technique that allows you to calculate this value.

Method for calculating the distance between rafters

The distance between the rafters on the roof is called the rafter pitch. As a rule, the pitch of the rafter legs in a roof structure usually exceeds one meter, and the minimum gap ranges between 60 centimeters.

Calculation of the required number of rafters for a roof of a certain length and the pitch of the rafters is carried out as follows:

Rafter structure for metal tiles

When constructing suburban private real estate, metal tile roofing can be found most often. This roofing material is similar to decking made from clay tiles, but compared to it has a number of advantages. Sheet metal tiles are easy to install, so you can build a roof in a shorter time; the rafter system for metal tiles is also not complicated.

Metal tiles are lighter than ceramic products; the difference in weight sometimes reaches 35 kilograms per square meter depending on the thickness of the products (read also: " "). Thanks to a significant reduction in the weight of the roof deck, it becomes possible to reduce the thickness of the elements of the rafter structure and the cross-sectional dimensions of the sheathing bars, and to increase the installation pitch of the rafters.

Under the metal tile covering, rafter legs are mounted at a distance of 600 to 950 millimeters, while the cross-section of the construction material is 150 by 50 millimeters. According to experts, in this case, if you place 150 millimeters thick insulation between the rafters, then such thermal insulation will create comfortable conditions for staying in the attic room. At the same time, for greater reliability, it is advisable to choose 200 mm insulation.

When installing rafters, to ensure ventilation of the space filled with insulation, holes with a diameter of 10-12 millimeters are drilled in the rafters near the upper roof.

The technology for creating a rafter system for metal tiles does not have significant differences from structures to other types of roofing materials. The only peculiarity is that the upper support of the rafters is mounted on the ridge girder from above, and not on the side of the ridge beam. The presence of a free zone between the rafters ensures air circulation under the roof deck, and this, due to the use of metal material, reduces the risk of condensation.

Rafter system of a pitched roof, main advantages and characteristics ").

The distance between the rafters of a gable roof is made taking into account the size of the heat insulator that is laid between them. Approximate step between rafter legs 1-1.2 meters (read: ""). Rafters regulate the amount of roof overhang.