Do-it-yourself installation of layered rafters. How to make roof rafters: selection of step and section. Full video report on the assembly of the rafter system

The rafter system is the basis of the roof, the reliability and strength of the roof, its ability to withstand precipitation and wind depend on it. The design of the rafter system is determined by the shape of the roof and the features of the layout of the house, as well as the materials used. A do-it-yourself rafter system is usually made of wood, but other materials can also be used, for example, a metal profile.

Types of rafters and their application

The choice of a rafter system is a crucial step that requires knowledge of the construction of each type of roof. Rafters can be:

Roof rafters supported by a ridge girder and a Mauerlat. They are used in the construction of a single-pitched, simple gable roof, as well as one of the elements of a hip and sloping attic roof.
Sliding rafters are a type of layered rafters used for wooden structures that give a large shrinkage. Their difference is the sliding fastening of the rafters to the Mauerlat, which makes it possible to compensate for the shrinkage of the walls without deforming the roof.
Hanging rafters - a system of rafters strapped with crossbars or ties, usually used in the construction of a simple gable roof, as well as as the upper rafters of a mansard roof. In the hanging rafter system, the ridge girder is absent, and in the upper part the symmetrical rafter legs rest directly on each other.
Oblique rafters, otherwise called angular or diagonal. They are used for making three-pitched or four-pitched roofs, as well as for roofs with complex geometry.

Elements of the rafter system

Any rafters are designed to distribute and transfer the load of the roof to the walls of the house. The main elements on which the rafters rest are:

Mauerlat - a bar fixed on the upper plane of the walls along the perimeter of the entire house;
Legs - support beams laid on internal load-bearing partitions or columns;
Top floor beams;
Racks and supports;
Girders are horizontal support elements laid along the roof axis on the pillars.

The roof truss consists of the following elements:

Rafter legs - boards or beams that form the contour of the roof and are laid with a certain pitch;
Puffs or crossbars are horizontal elements that pull the paired rafter legs together;
Braces - supports set at an angle and supporting the rafter legs;
Fillies - boards fixed at the lower end of the rafters and forming the overhangs of the roof;

Narodniks are short rafters supported by diagonal rafters in a hip roof.

All these elements in private construction are usually made of wood - timber or coniferous boards, dried in a natural way. The tree is impregnated with an antiseptic, which makes it possible to extend its service life. The thickness and section of the elements is determined by calculation.

The technology of performing layered rafters

Before starting construction, you need to sketch the roof and calculate its dimensions. The section and pitch of the rafters, as well as the need to install additional supports and struts, are also determined by calculation.
Support elements are laid and exposed: Mauerlat, beds and floor beams, racks, ridge and intermediate runs. These operations are described in detail in articles on various types of roofs:
A rafter template is made. To do this, take a board with a width corresponding to the calculated length of the rafters, with the same width, but with a smaller thickness - it is lighter and easier to fit exactly in place. The board is applied to the installation site of the extreme rafter with one end to the ridge girder, the other to the Mauerlat.
At the top of the template, mark the upper cut. The shape of the gash should be such that the board lies on the ridge girder and at the same time fits snugly against the opposite rafter. The depth of the cut should be no more than 1/3 of the board width.
After sawing out the upper cut, the template is again applied in place and the lower cut is marked - it should rest on the Mauerlat, without leaving large gaps. The end of the template is sawed off at an angle so that the cut is in the vertical plane.
The resulting template is applied at the installation site of all rafter legs, checking if a fit will be needed in place. If the template fits perfectly (which rarely happens), you can immediately make the required number of rafter legs. If you need to adjust the bottom cut, then only the upper part of each rafter is cut out according to the templates, and the bottom cut is made in place each time.
The rafters are placed with a set calculation step. It usually ranges from 50 to 120 cm and depends on the type of roof covering, namely its severity and the expected snow load. The heaviest coverings are slate and ceramic tiles, but these are rarely used today. More often, the choice is made in favor of more modern, lightweight and reliable materials: metal tiles, ondulin, soft roofing. For them, the pitch of the rafters can be chosen about 100 cm without performing complex calculations.
First, the rafters are installed from the side of the gables. The rafter leg is supported on the ridge girder and the Mauerlat and fixed on two 100-150 mm nails at each attachment point. Having installed a rafter pair, they additionally fasten it: in the upper part with the help of metal plates and self-tapping screws on one side and corners with a stiffener on the other, in the lower part - with brackets or also on corners.
After installing the rafters, a twine is pulled between them from both gables of the roof and the remaining rafters are aligned along it. The rafters are fastened in the same way.
Install struts, if required by the results of the calculation. The braces are made of the same material as the rafters. Apply a board of suitable length at the desired angle to the rafter and mark the bottom cut. It is important to take into account what the brace will rely on: on the floor beam or on the bed, the shape of the bottom cut depends on this. After completing the lower cut, the strut is placed in place and the cutting line is marked along the rafters. The prepared strut is placed between the beams and rafters and fixed with metal plates or corners.

Installation of struts on the roof

Technology of execution of hip diagonal rafters

Since the rafters for the hip roof are installed diagonally, the usual methods of fastening them are not suitable. In addition, the load on the diagonal rafters is much higher than on the layered or hanging ones, so the material for their implementation must have a larger section. You can use a beam with a thickness of 100 mm, but practice shows that it is more convenient to make these rafters from two folded and fastened boards of standard thickness.
The diagonal rafters are supported with the upper end on the racks, with the lower end on the Mauerlat bars converging at right angles. They are marked in place, and their main feature is that the cuts are performed not perpendicular to the plane of the board, but at an angle of 45 degrees. When making rafters from spliced boards, first one side is performed with oblique cuts, then the second, in a mirror image.
The boards are pulled together with screws, nails or hairpins. Hip rafters are fixed with pads and self-tapping screws.

A video will help you better understand the basic techniques for erecting a rafter system with your own hands.

When performing any rafter system with your own hands, it is important to carefully secure all nodes and connections and remember that the roof is the main protection of your house from bad weather. Therefore, it is important not only to make a high-quality frame, but also to choose a suitable one, for example, corrugated board, and lay it correctly.

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The roof is essential to the integrity of the entire home. Therefore, many are interested in how to properly assemble the rafter system so that it is reliable, and soon it does not have to be repaired. There are many types of roofs, some of them can be seen in the photo, but the most popular are single-slope and gable structures. Let's figure out how to make the truss system correctly.

Roof types

Before moving on to how to make a rafter system, you need to understand what the common types of roofs are.

A pitched roof is the simplest one, even a person who does not have much experience in construction can cope with its creation. However, this type of roof is used mainly in the construction of outbuildings. For residential buildings, gable or mansard (broken) roofs are usually made. These structures are more complex, but you can easily cope with them on your own if you know how to make gable roof rafters and follow all the recommendations of specialists (read: "").

The most reliable roofs are hip roofs, they can withstand even huge loads. It is recommended to do them in those regions where there is a lot of snow and strong winds often blow. But their design is also very complex, so it is better to entrust their construction to professionals.

The hip (hipped) roof is used in the construction of square buildings; by its design, it is a type of hip roof.

The most difficult roof is the cross. During its construction, complex structural elements are used - valleys (gutters). These diagonal auxiliary rafters are installed as additional elements. When building such a complex roof, haste is unacceptable. In the area of the grooves, the bulk of the snow accumulates, and the reliability of the roof depends on how to make the rafters in these places.

Each type of roof consists of rafters and a roof covering. The rafters are the supporting part of the roof, and the roof surface is the enclosing part.

Types of rafters

Before you put the rafters, you need to find out about their design features and decide on the installation option.

There are two types of rafters: layered and hanging .

Hanging rafters - these are inclined beams mounted on supports with different heights. The support can be the outer walls of the house (in the case of a pitched roof) or both interior and exterior walls (in the case of a gable roof). Rafter legs do not have to be laid in the same plane opposite the slopes. They can be mounted alternately on a ridge girder. The alternating laying of the rafters in the ridge area makes it possible to create a rafter truss. For this purpose, all the details are connected together into a single rigid structure.

Materials for rafters

As for the rafters made of boards, they are not heavy, and they are convenient to install. You can easily work with this material on your own without resorting to outside help. Many experts advise against making connections with nails - it is better to use self-tapping screws. If the work will be carried out with the help of nails, do not forget about the linings and inserts.

As for how to build a rafter system, it is better to use cuts to connect the racks with a run or a bed.

Do-it-yourself installation of the rafter system, in detail on the video:

Connection options for the rafter system

The rafter system can be connected in three ways:

struts;
racks;
simultaneously with struts and struts.

How to make the rafters correctly depends on the span between the outer walls. A 10x10 cm beam is used to create a ridge run. Lezhen and Mauerlat can be made from logs by cutting them into two edges, or by taking a beam of 10x10 centimeters.

When decorating the ridge knot, it is necessary to nail special clamps made of steel strip with large nails to the Mauerlat and the girder, taking into account. It is possible not to use steel clamps, but then twists from a thick wire with a diameter of 6 millimeters are needed.

Regarding how to make a brick or stone house, then a Mauerlat must be laid on the masonry. To secure it securely, it is recommended to put a piece of log or timber about 50 centimeters under each rafter leg. Then they are attached with clamps to metal hooks that were previously installed 30 centimeters below the Mauerlat.

Many people have a question about how to make rafters on the roof of wooden houses. Rafters in wooden buildings are placed on the upper crown of the wall. A plank truss can be created with a crossbar or with spans (6-8 centimeters). Its structural elements are arranged as follows. A single tightening is made using boards, the thickness of which is equal to the thickness of the rafters. For double tightening, thinner boards (from 40 millimeters thick) are used. For the deadbolt and overlays, take 30 mm parts.

How to determine the cross section of the rafters

Before placing the rafters correctly, you need to decide on their cross section.

This parameter depends on:

span dimensions;
estimated load (wind force, weight of snow cover and roofing material);
step and angle of installation of rafters (roof slope).

There is a dependence of the cross-section of the rafters on the length of the rafter leg.

It is expressed in the following:

with a step of 300 centimeters, beams with a section of 10x12 centimeters or boards with a section of 6x14, 8x14 or 4x18 centimeters are used;
at a step of 400 centimeters, beams with a section of 10x16 centimeters or boards with a section of 6x20, 8x20 centimeters are used;
with a step of 500 centimeters, beams with a section of 10x20 centimeters or boards with a section of 8x22 centimeters are used.

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The roof covering must be selected taking into account the slope of the roof. Also, the choice of material for the roof depends on financial capabilities. The larger the slope angle of the roof, the more funds will be required to create the roof - this is due to the increased consumption of materials. However, steep roofs are better at draining rainwater and snow, so they are more reliable and will not require repairs longer. But given the huge selection of roofing materials on the market, this will not be difficult.

Creation of a truss system for a bath

As for how to make the rafters for the bath, it is better to choose a gable roof - then the building will have an attic room that can be used to store brooms and other bath accessories (read: ""). Thus, it is desirable to create a rafter system under a gable roof, it is easier and more practical.

Roof installation is a complex technological process, which includes the stages of design, assembly of the frame, flooring of roofing material and installation of auxiliary elements. While it is not easy to properly design a roof to keep the cost of roofing down, with some basic building skills and tools, you can do it yourself. In this article, we will describe in detail the sequence of actions necessary to independently carry out the installation of the roof truss system of a private house.

The roof rafter frame is a combination of wooden elements that form a kind of "skeleton" of the structure that supports the roof slopes, giving them the necessary shape. If desired, the rafter system can be made by hand, the main thing is to correctly calculate the loads and determine the composition of the structure. The functions of the roof frame are:

Support for roof slopes. The rafter legs give the surface of the roof slopes the slope necessary so that melt or rain water can be efficiently drained from them, and snow masses come off on their own.
Roof weight distribution. A correctly calculated frame structure evenly distributes the weight of the roofing cake on the load-bearing walls and the foundation of the structure, preventing deformations and subsidence of the supports.
Place for fixing the roofing material. Those who have blocked the roof with their own hands at least once know that the frame crate serves as the basis for fixing the waterproofing coating.

Note! The rafter frame is made of wood or galvanized metal. The choice of material determines the cost of roofing, service life and load-bearing capacity of the roof. Experienced craftsmen believe: if the length of the slope does not exceed 6 meters, it is much more rational to make these elements from wood.

Project creation

Before you make the rafters for the roof of a private house with your own hands, you need to create a working design of the structure, taking into account the climatic conditions in the area where the construction is taking place, the method of using the attic space, and the type of roofing. All these factors are taken into account when calculating the loads that affect the roof frame. To determine the required load-bearing capacity and create a roof project, it is necessary to determine:

The cumulative load on the rafters. To do this, constant loads (the weight of the rafter system itself, insulation, roofing material and waterproofing) are summed up with temporary loads (snow, wind and natural load). The total weight of the roofing cake when using thermal insulation can reach up to 700 kg.
The height of the roof ridge. This indicator is calculated based on the desired slope of the slopes and the width of the structure to be covered. Also, the method of using the attic affects the height of the ridge: if a residential attic is equipped in it, the ridge must be located at least 250 cm from the ceiling.
The slope of the slopes. The angle of inclination of the roof slopes is calculated as the quotient of the height of the ridge and half of the roof base. This factor depends on the climatic conditions in the construction region, as well as the characteristics of the roofing material.

Important! The result of calculating the total loads, the height of the ridge and the slope of the slopes is a correctly designed, detailed diagram of the rafter frame, which will facilitate the manufacture of the structure with your own hands, and also reduce the risk of errors.

Selection and preparation of material

To make a strong and durable truss frame for the roof of a private house, hardwood or metal profiles are used. The final cost, weight, service life and bearing capacity of the finished structure depend on the choice of material. For DIY work, experienced craftsmen recommend choosing wood. In order for the rafters to serve for a long time, it is necessary to check the compliance of the sawn timber with the standard:

The moisture content of lumber used for making rafters with your own hands should not exceed 19-21%. Damp wood during the drying process can crack, warp, which causes deformations and distortions in the roof.
The tree must be healthy. That is, it should have a light color characteristic of the breed, not have foci of decay, mold, darkening or traces of pests.
For the manufacture of rafters, it is recommended to choose straight, even boards without a large number of knots, as they reduce the strength of the supports.

Please note that the wooden truss frame will last a long time, before starting work on assembling the structure, they will process the components with a deep penetration antiseptic with their own hands, and to reduce firefighters, impregnation with a fire-blocking compound is performed.

Mauerlat bookmark

Installation of the truss system of a low-rise building begins with the laying of the Mauerlat. These terms denote a support bar, which is mounted on the upper trim of the load-bearing walls where the roof slope rests on them. The number of Mauerlat beams involved in the design always coincides with the number of slopes. Mauerlat is made from a thick wooden beam with a thickness of 10-15 cm. The laying of this frame element is carried out in accordance with the following rules:

Mauerlat is mounted only if the box of the house is made of brick, concrete, gas silicate, foam block. In wooden buildings, the role of the mauerlat is played by the upper rims of the log house, firmly fixed with metal brackets or dowels.
Some types of layered rafter systems do not provide for the installation of a Mauerlat, since they do not exert a bursting load on the walls of the structure.
Strong waterproofing is always laid between the wall of the house and the Mauerlat to prevent condensation from settling or wood decay. For these purposes, use glassine, roofing material or roofing felt.
It is not allowed to make a tie-in under the rafter legs in the Mauerlat, since each violation of the integrity reduces the strength of the beam.
The Mauerlat bar is fastened with studs embedded in the wall of the house, or with long anchor bolts.

Do not forget that before installation, it is advisable to treat the Mauerlat with a deep penetration antiseptic to prevent wood decay, and also impregnate it with a fire retardant to protect the roof frame from fire.

Assembly technology

The degree of complexity and sequence of assembly of the roof truss frame depends primarily on the design and type of rafters. To do the installation yourself, it is better to choose simpler gable structures. If load-bearing walls are provided inside the house, then a layered rafter system can be used. The assembly of the frame takes place in several stages:

Mauerlat bookmark and bed. At this stage, it is important to firmly fix the support beams along the load-bearing walls with metal studs or anchors.
On the bed, laid on the inner bearing wall, vertical posts are installed with a step of 1.2-1.5 meters. To keep them upright, temporary supports are installed.
A ridge run is laid on the racks from above. It pulls together the vertical supports and serves as the basis for the installation of rafter legs.
Mount the rafter legs. One end of the rafter is attached to the Mauerlat, and the other to the ridge girder.
Perpendicular to the rafters, the crate is nailed, on which the roofing is laid.

Remember that you can only overlap a wooden house with your own hands after the box has completely shrunk. To compensate for the change in the geometry of the roof, movable fasteners are used that adapt to the size of the house.

Video instruction

In building your dream home, you are already on the home stretch, and it's time to figure out the intricacies of the rafter system? Let's just say: pleasant worries await you: calculating the angle, weight and safety factor of rafters, an agreement with a familiar craftsman or a 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 node is being done correctly, we have prepared this article for you. So, let's figure out how to make high-quality rafters for a gable roof with your own hands so that it is no worse than purchased ones.

Short terms of production.
Technological precision of all details.
The same, already adjusted dimensions of all structural elements.

But then be prepared for the following disadvantages:

High cost (at least twice as high as if you planed the rafters yourself).
Delay in delivery (especially in season).
The use of low-quality or under-dried wood (and then "lead" the roof).

So convenience or quality? If this is not the first time for you to cut or cut something out of wood, feel free to start making rafters! This is how it all looks in real life:

Rafters in the construction world in simple language are usually divided into basic ones, i.e. carriers, on which the roof is held, and auxiliary ones, which are located inside the roof and serve as a support for hemming the ceiling and walls of the attic (if such 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.
Rigeli.
Rafter legs.
Spacers.
Ridge run.

It is better to entrust the calculation of complex roof structures with multiple elements to a professional, but you can cope with a small roof of a private house. 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?

The golden rule applies in the construction of roofs - measure seven times, and cut off 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 better in a special program. Only after that, according to your ZD model of the future roof, mark exactly where and what kind of connections of the rafters with the Mauerlat and between themselves will be.

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

Determine the angle of inclination of the roof: calculate the loads

The angle of inclination of the gable roof is made from 5 ° to 90 °. But the most proven and standard option is 35 ° -40 °, where loads are most rationally distributed 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 heat exchange control. But when the under-roof space is planned for residential, attic, the so-called broken gable roof is initially planned. Its difference is that the slopes in the middle have a kind of break, which changes their angle to a steeper one. And for arranging the attic, and for protecting the whole house from bad weather, this design is quite suitable.

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

Constant and variable roof loads

It depends on the same loads what step of the rafters needs to be done for your gable roof. This table will help you choose the desired section of the rafter legs:

Indicators of rafters for deflection

Even strong-looking rafters may not be suitable for the construction of the roof of a residential building due to the fact that they do not have sufficient deflection performance. There are separate items in the SNiP section, which are called “Loads and Impacts”.

And the easiest way to increase the deflection strength of the rafters is to make a larger section. A little more difficult is to reinforce it with a special beam, bringing its edge to the brace.

Reinforcing elements for rafters

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

If you have a suspicion or even an accurate calculation that a simple roof structure will not withstand future loads, make additional reinforcement elements for it. Such prevention never hurts, but it will save you from many problems. Note that it is especially offensive when the garage roof collapses - right onto the car. And for a residential building, such problems are not a joy.

Strengthen the rigidity of the rafter structure with 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 girder is a horizontal beam that is parallel to the ridge and fixed on vertical posts. More on video:

Determine the type of roof: cold or warm?

And now about the concept of an attic. If you are building the roof of a bathhouse or a small master's room, it can be done using the most simplified technology - you put the rafters, connected in a ridge and covered with sheets of roofing material. But for the roof of a residential building, where ventilation is important, this principle cannot be dispensed with. There will already be at least three levels:

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

It is so convenient to lay insulation, because the roof of a residential building is distinguished by the fact that heat rises upward and, in the absence of thermal insulation, the roof covering is constantly heated.

Bottom line: in winter, the snow melts and slides down, freezing and accumulating even more at the cold cornice. There are a lot of problems from this: long dangerous icicles, and a 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 over 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. So, rafters are divided into layered, hanging and hybrid.

Hanging rafters are usually the lot of small and light roofs, the distance between the supports of which does not exceed 6 meters. But in buildings with a load-bearing middle wall or additional supports for the roof fortress, layered rafters are arranged. Or here is such a combined option:

Another difference is that the hanging rafter system makes the Mauerlat work in compression, and the layered one - in shear. But the main task of both layered and hanging rafters is to transfer the loads of the entire roof to the walls and foundation as evenly as possible.

We select the material for the rafters

So, if you have decided on the future loads, it's time to choose the right material. As it for the manufacture of rafters, they are usually used:

Wood. Solid wood, boards or glued beams.
Lightweight metal profile. These are galvanized steel profiles.
Black metal. These are I-beams and steel channels.
Heavy reinforced concrete structures for industrial construction.

Dry board: the economical option

If heavy loads are not expected on the rafter system, then make the rafters from dry planed boards with a small section. But if in your area it is not uncommon for knee-deep snow and the roofing material is not easy, then you will have to make glued some of the constituent elements. 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. Not less than 50 mm! Moreover, the longer the rafter leg is planned, the wider the board itself should be. So, rafters with a length of 6 meters will have to be made from a board with a width of 150 mm, and even longer - from a board of 180 mm.

For the roof of a frame house, this is really one of the best options!

And the rafters from the board are the most economical, and at the same time they are almost not inferior in strength to the timber ones. It is only important to choose the right cross-section and use high-quality material. Therefore, when buying material, be sure to take a special device for measuring the moisture content of wood and use it. There is nothing worse than raw rafters. And it's not just about the future mold: such a roof will lead and warp, because this material changes its shape when it dries. At the rafters, fastenings will fly and even the covering of your gable roof will bounce off in places. In a word, you will not end up with problems!

But from an ordinary board, it is most convenient to splicate the rafters along the length:

Durable metal: resists moisture

And, you will be interested to know that rafters can be made not only from wood! So, iron truss systems, which were once used exclusively for industrial construction, are returning their former popularity today. And, note, this material for the roof has many of its advantages, the most valuable of which is the complete absence of fungus from dampness. The under-roof space, after all, most often "pleases" with accidental leaks.

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

Bars: the benefits of quality wood

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

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

Humidity not 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 running meter - no more than three knots, and each of them - no more than 30 mm in diameter.

Therefore, when buying wood for rafters, be sure to check the documents with the seller, which speak about the quality of the products.

The type of wood is also important. The fewer knots and cracks on the bars, the better. Some varieties also delight in good moisture resistance and resistance to decay 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 decay. But special processing is still needed.

And take into account this fact: when making a rafter system, you need to purchase 5-7% more material than necessary, because it will not always be possible to make a perfect rafter cut or a cut of the required depth. Overruns will still be, and therefore stock up on them in advance so that for the entire rafter system you have a tree of the same moisture content and properties.

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

Treatment with antiseptics and propylene

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

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

But the choice of means for processing today is huge. These are universal protective agents, and a variety of fire retardants, and antiseptics. It is easy to decide: if you are building in a sufficiently hot and arid area, first of all use fireproof impregnations, which deprive the wood of its natural flammability. And if your house will stand where the air humidity is high almost all year round, protect it from decay.

You can, of course, use both drugs - but not mixing, otherwise all the material will deteriorate. You just need to choose one agent as an impregnation, and the second as a protective surface layer. Just try to breed everything in the concentration indicated by the manufacturer. But do not process frozen or damp wood with anything: its fibers simply will not absorb anything.

Video tip on the topic of rafter processing:

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 a film from the inside and make a "bathroom" for future rafters. Moreover, it is advisable to turn all this on the ground, as soon as you bring the material to the place, tk. in the finished rafter system, it will be difficult to get to the internal elements of the connections. And they are the most defenseless in terms of moisture ingress. Dry after processing the part so that all sides are ventilated and for at least 24 hours.

Do not forget also that wood, like any natural material, is biodegradable. 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 get down 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 a 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 are doing!

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 fact, everything is quite simple and is somewhat similar to a children's designer. The easiest and most convenient way is to make trusses right 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 the starting point: if you have the opportunity (a crane, for example) to drag 200 kg of one farm onto the roof - drag, if not - lift each individual rafter 50 kg each with the help of improvised means and assemble it on the spot.

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

Attention to strength - length extension rules

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

To rally the boards together, folding them with wide sides and stitching them with nails.
Lay the boards in half the length, resulting in a particularly strong rafter leg that can withstand considerable loads.
Make an oblique cut at the ends to create a vertical anti-slip stop, and connect with a bolt.
Lay two boards with an overlap in length of a meter, connecting the rafters with pins or nails.

Also take into account when calculating that the ridge of the roof accounts for about 50% of the load from the entire rafter system. Therefore, always make a ridge beam so that its safety margin is at least 25% more than originally calculated.

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

Cooking roof trusses

You need to fix the truss nodes using:

External straight staple.
Metal corner plate.
Internal metal rod.

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

Let's start with an overview of proven old-fashioned methods:

Here's how they work:

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 make the roof, connect the beams with cut planes and fix with two nails. Cover the joint with a wooden plate or a metal plate.

Another useful master class:

Lifting and installing ready-made trusses

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

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

The rest is a matter of technology:

The roof is a complex and important architectural element of any building. Its construction should be treated with special attention, it must be remembered that the installation of the rafter system requires considerable experience in performing such work and a special tool. You should not undertake the creation of a roof for those who for the first time hold a carpentry and measuring tool in their hands - the results of activity can be very negative.

There are two types of roofs, depending on the number and placement of the rafter support points, but each developer can, at his discretion, slightly change the specific structure of the rafter system. This takes into account the operating conditions of the building, the purpose of the attic, the climatic zone of the location, the technical parameters of lumber and roofing. Of course, the appearance of the rafter system is influenced by the personal experience and preferences of the developers.

Before proceeding with the manufacture of rafters, you should decide on their type, method of fastening and linear dimensions. Only in this case, you can be sure of the strength and safety of the structure.

How do various factors affect the parameters of the rafters?

Physical factor	A brief description of the effect on the parameters of the rafters
	The rafters must withstand snow and wind loads. During the calculations, you need to take the actual maximum values of snow cover from the tables of building codes and regulations, take into account the strength and wind rose. The data allows you to find out the total load on the roof slope, depending on its area and angle of inclination. Further, it is already possible to determine the dimensions of the rafters, their number and step. In this case, a safety factor must be included. The fact is that lumber does not have stable and identical strength values, too many unforeseen factors affect these indicators. For most cases, boards of 50 × 150 mm or 50 × 200 mm are used for the manufacture of rafter legs.
	Gable roofs can be layered and suspended. For hanging roofs, you need to make rafters from more durable boards. This takes into account the method of fixing the elements to the Mauerlat. If a cut is made, then the width of the boards should increase by the size of the cut. The fact is that the cut in this place automatically reduces the width of the material that takes the load. If a transverse cut with a length of 60 mm is made on a board 200 mm thick, then only the remaining width of 140 mm is taken into account. Accordingly, if, when calculating the loads, rafters from 200 mm boards are selected, but during fastening, unintended cuts of 60 mm are made, then the width of the blanks for the rafters increases to 260 mm. This remark is made for those who like to abuse the various cuts and cuts for the rafter end rafters. Currently, there are many special devices that allow you to firmly fix the rafter in the desired position without filing.
	For residential buildings, the rafters must have a safety margin of at least 1.4 of the calculated values. For non-residential buildings, the coefficient is reduced to 1.2. Conclusion - the dimensions of the rafter boards on houses are larger than on garages and other outbuildings.
	Residential attics (attics) must have an insulated roof. The width of the rafters should correspond to the thickness of the insulation layer. At the same time, you need to adjust the step between the rafter legs, depending on the standard width of the insulation. If in a given climatic zone the optimal thickness of the roof insulation is 200 mm, then it is recommended to choose the same width for the rafters. Various extensions of narrow rafter legs during roof insulation are not considered the right solution.

This knowledge will help you make the right decisions both during the manufacture of rafters and during their fixation directly in place. Mistakes in the construction of a rafter system are too expensive, you should not show excessive self-confidence.

What influences the choicesizes andwaysfasteningsrafter

A very important point. The task of any fixation is to ensure the stability of the connection node, while it can be motionless or have one or more degrees of freedom. This cannot be achieved without knowing the loads that affect the rafter legs. Loads can be permanent and temporary, dynamic and static, unidirectional and multidirectional.

Constant vertical forces... They arise due to the influence of roofing and insulation materials of the roof. Due to the fact that the rafter legs are located at an angle to the vertical force, they are subjected to bending and bursting loads. The magnitude of the forces is determined after plotting the diagram, based on the specific bending and expanding forces, the thickness and width of the boards for the rafters are selected. Fasteners should prevent the rafter system from creeping.
Variable vertical forces. Appear in winter, the value depends on the height of the snow cover.
Raising wind forces. As a result of gusts of wind, lifting forces act on the roof. The dimensions of the rafter legs are not influenced, the efforts are taken into account only when choosing the type of fixation, it must provide for and hold such loads.
Lateral forces. The value depends on the windage of the roof. As a result of gusts of wind, lateral forces act on the rafter system. They increase bending and pull-off loads. This feature must also be taken into account during the manufacture and installation of rafter legs.

There are options for rigid fastenings of trusses, metal plates, corners, screws and nails are used for this.

Sometimes it is necessary to use floating rafter joints to compensate for changes in the size of wooden houses. For floating connections, special fasteners and bolts are used. The latter allow the rafter legs at the top to rotate slightly.

Another example of a free connection of rafters is a sliding one. It is used on wooden log cabins and makes it possible to compensate for the natural shrinkage of the house.

What elements are used to increase the stability and bearing capacity of the rafters

As a result of the correct choice of the rafter system and the methods of fixing its elements, the structure must be stable, compensate for natural fluctuations in linear parameters and withstand various loads that arise during operation. To fulfill the conditions during the fixation of the rafters, additional fixation elements can be used.

Runs

Most often they are mounted in the ridge part of the system, the upper ends of the rafter legs rest on them. To increase stability, cuts may be provided. The top connection is rigid or floating with bolts. On large roofs, purlins can be installed in the middle of the rafter legs or in other places with critical loads.

Vertikalinen racks

They are installed to strengthen the rafters; due to the use of racks, elements can be made from thinner lumber. The upper end of the vertical posts abuts against the rafters, and the lower end against the bed or ceiling beams.

CornerOpores

Retains bending and expansion forces, universal use. Corner stops can be placed in any place of the rafter leg, causing concern about the strength. Due to such stops, the resistance of the rafters to bending and tearing forces is significantly increased.

Puffs(crossbars)

Purpose - to keep the rafter legs from spreading, are used on hanging rafter systems. Most often they are placed in the upper part of the truss; for manufacturing, you can use boards with a thickness of about 20-25mm. The fact is that they work in tension, lumber holds such forces well. Boards do not work well in compression, they quickly bend and lose their original strength.

Tiltadki

They are used in the upper ridge part of the rafters, due to the use of puffs, the strength of the knot connection increases. Ties can be made from wood, plywood, OSB or metal.

Lugs(stops)

They have many specific names. They are ordinary pieces of boards 30–40 cm long and 40–50 mm thick, fixed in the lower part of the rafters. They rest on the Mauerlat and do not allow the structure to slip. The use of bosses allows you to perform a rigid connection of elements without filing the rafters. In this article, we talked about the problems arising in connection with filing above.

Prices for various types of timber

Connection options for the ridge knot of the rafter legs

The ridge is one of the main and most loaded elements of the rafter system. The node has several connection options, the specific one should be chosen depending on the general parameters of the roof.

With a large length of slopes, it is better not to use a ridge bar, but instead put two parallel runs and tightening bolts. This construction is easier to make, more stable and safer.

For a hanging roof, you should choose the most reliable ways to connect the rafter legs; these systems have a minimum number of additional stops.

Prices for various types of fasteners for rafters

Fasteners for rafters

Step by step inwithTruktion of mouthanew rafters

For rafter legs, 50 × 200 mm coniferous boards, first grade sawn timber are used. Boards cannot have traces of rot or fungus, significant malformations and deep cracks. It is strictly forbidden to use low-quality lumber for the manufacture of the truss system.

To increase the protection of the elements of the roof from decay, it is recommended to use fire-retardant protection.

The blanks of rafters should be impregnated at least twice, while the material should be dry and clean. Processing is done on a level surface in dry and clear weather.

It can be impregnated with a roller, brush or pneumatic tool. It is not recommended to use household hand sprayers - it is too long and difficult. The boards can be lifted to the top after the impregnation is completely dry.

Our gable roof has a ridge girder, the vertical supports rest on the bench located on the load-bearing wall in the middle of the building.

Practical advice. If the house is quite tall and the boards are heavy, it is recommended to make an elementary device to protect the window openings from damage. To do this, two boards are knocked down in the form of a square, the length and width are selected taking into account the parameters of the opening. The device is installed on the windowsill, and the rafter boards do not damage the foam blocks during lifting.

Prices for fire retardant impregnations

Preparatory operations

The manufacture of rafters begins with preparatory operations.

Step 1. Lift the rafter boards into the attic. For convenience, place them evenly along the length of the building, put one end on the Mauerlat, and the other on the girder bed. First, you need to install the extreme rafters on both sides of the roof of the house, pull a thread between them and install and align all the remaining ones along it.

Step 2. Check the position of the ridge run again. It should be located exactly in the middle of the roof. Its displacement by 1–2 centimeters will not affect the strength of the roof as a whole, but it will somewhat complicate the manufacture of rafters and the laying of roofing materials. In addition, an experienced builder may notice a mismatch in the dimensions of the slopes and, accordingly, the asymmetry of the roof. It is recommended to achieve a situation that the ridge run is located along the line of symmetry, if this is not associated with great difficulties. The final decision is made by the foreman on the spot and depends on the amount of displacement and the amount of work to correct the error.

How to align the purlin?

Attach a sheathing board to the Mauerlat, it is lighter, easier to lift and fix. The other end should be on the girder. The board is nailed to the Mauerlat with an ordinary smooth nail or screwed with a self-tapping screw.
Climb to the top of the girder and use a tape measure to check the distance from the edge of the shoulder strap to the Mauerlats installed on opposite walls. Work very carefully, it is advisable to use insurance. Unfortunately, in practice, few people follow the safety rules, but in vain. Falls from a height cause very serious injury.
Align the purlin to the center and secure the board. To increase rigidity, fix the same board on the other side of the purlin.

Now everything is ready, you can start making and installing rafters.

Installationrafter legs

If you are working alone, then a piece of rail must be screwed to the girder at the place of fixation of the first rafter. A rafter board will be temporarily fixed to it to prevent it from sliding down.

And at this time, you can carry out work on the manufacture and preparation for the connection of the upper part of the rafters.

Step 1. Lift and install the rafter board, clamp it to the previously fixed rail with a clamp.

Step 2. Draw lines to cut out the abutment. This is done in two stages. First, draw a horizontal line. To do this, press the rail, square or other flat object firmly against the horizontal surface of the purlin.

Second, draw a vertical line. Now the ruler or square should be pressed against the side surface of the purlin.

Important. The width of the ruler should be no more than 2-3 cm, it is not necessary to make deep cuts and greatly reduce the width of the rafter leg, it loses its maximum design strength.

Make the same markings at the bottom of the rafters. Only now the ruler needs to be pressed against the surfaces of the Mauerlat.

Step 3. Remove the board and carefully cut out the seats. You can work with a hacksaw or an electric circular hand saw.

Practical advice. If the cuts are made with an electric circular saw, then it is better to cut in two steps. Cut to the mark for the first time, then turn the board upside down and cut again to the mark. Use a hammer to knock out the cut piece, and remove the remaining protrusion with a chisel or chisel. You do not need to go over the line with the saw and try to cut off the protrusion in one go. This method increases the cut by 3-5 cm, depending on the diameter of the disc, which significantly reduces the bearing performance of the rafters.

Step 4. Install the prepared rafter in place and check if it was made correctly. Do the same operations with the second leg of the truss.

Step 5. Place the rafters with an emphasis on the Mauerlat and the girder, tighten them with a clamp at the top. Find the middle of the purlin and transfer the line to the rafters, use a level or construction square (only if the plane of the purlin is strictly horizontal).

Step 6. Saw two rafters at the same time in a vertical line. The boards should be tightly clamped with a clamp. Make sure that the saw blade is perpendicular to the plane of the rafters. If you saw it obliquely, then the ridge joint will fit loosely, and this reduces the stability of the rafter system and is considered an obvious building defect.

With a lack of practical experience in performing such work, the first leg may have a gap in the ridge part, if it is within 1–2 mm, then there is nothing to worry about. If it is more than 4 millimeters, then you need to correct the element. See which planes of the thrust pads do not allow the upper cut to fit tightly. Indicate the approximate amount of additional cut. Remove the rafter and remove the obstructing projections. Check the connection again, if the gaps remain - repeat the operation. As practice shows, experience appears on the second or third rafter and no further corrections need to be made.

Step 8. Fasten the rafter legs firmly in place. For this, it is recommended to use metal plates and corners, it is simple and easy to work with them, the strength fully meets the requirements for the rafter system.

For each pair of rafters, you will need one large reformed plate to connect the ridge knot, two 50 × 50mm corners for fixing to the girder and two 60 × 80mm corners for screwing to the Mauerlat. The thickness of the metal is at least two millimeters.

In the same way, install the extreme rafters on the other side of the house, pull the threads between them. One at the top and bottom and one in the middle. To prevent them from interfering during the manufacture of rafters, make a gap between the thread and the plane of about one centimeter.

Real professionals never make one rafter in the attic of a house. Such an algorithm of work significantly increases the construction time, complicates the process itself and makes it unsafe. It is very dangerous to work with electric tools on unsuitable sites, the injuries from them are severe, and often cause disability.

If the house is delivered with high quality, with exact observance of the dimensions and rules, then the rafter legs are made according to the same template on the ground. The finished elements are assembled on the roof. This technology increases labor productivity by 3–5 times, at the same time improves the quality of the rafter system, it is more reliable and durable. Of course, the wages of builders are also increasing proportionally. They work from the site and receive money not for the time spent in the attic, but for the assembled roof.

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