Installing rafters yourself - expert recommendations. How to properly make a rafter system for a gable roof with your own hands How to make rafters for a roof

Installation of rafters is one of the key stages of roof construction. To ensure that the rafter system does not deform or collapse under high loads during operation, the rafters must be properly secured.

Calculation of rafter pitch

When designing a rafter system, special attention is paid to this issue. The strength characteristics of the roofing system depend on the cross-section of the rafters and the pitch of their installation.

The rafter pitch is the distance between adjacent rafter legs. The minimum pitch of the rafters is 60 cm, the maximum is more than 1 meter. A simplified version of calculating rafter pitch involves using the table:

The length of the eaves slope must be divided by the rafter pitch selected in the table, then add one to the resulting value and round up to a whole number. The resulting result indicates the required number of rafter legs per slope. Then the length of the slope along the eaves should be divided by the calculated number of rafter legs - the final number corresponds to the value of the center distance between the rafters.

This calculation method is general; it does not take into account the specifics of roofing coverings and the type of insulation used. If you intend to lay a roll or slab insulator, it is recommended to adjust the pitch of the rafters to the size of the material. It should be taken into account that the width of the cotton insulation should be 1-1.5 cm greater than the span between the rafters.

When determining at what distance to install the rafters, you should also pay attention to the recommendations for installing the selected roofing covering.

Preparation of material

Installing rafters with your own hands requires not only knowledge of the process technology, but also proper preparation of the wooden elements of the system for installation. The rafters are made from edged boards or timber; the cross-section of the lumber is selected at the roof design stage. The tree should not have cracks, wormholes or other damage.

Rafter legs should be made of well-dried coniferous wood to prevent their deformation.

Wooden elements must be treated with fire retardant and bioprotective compounds. Before you begin installation, you need to decide on the method of attaching the rafters to the mauerlat or beams, and the type of ridge connection. In accordance with the project, metal and wooden fasteners are selected, including:

plates (made of metal or wood);
bolts or studs with nuts and wide washers;
nails, screws, staples, etc.;
wire rod.

Types of rafters and features of their installation

When constructing the roof of a house, hanging or layered rafters are used. In some cases, a combination of both may be used. Hanging ones rest only on the walls of the building, while layered ones require the installation of additional supporting structures, so this option is primarily used if there is a middle load-bearing wall or support pillars inside the building box.

The lower part of the layered rafters rests against the mauerlat; accordingly, the walls of the structure must have sufficient width for the installation of a special supporting structure made of timber with a cross-section of 150×150 mm. The upper part of the layered rafters rests on the ridge girder. Thus, installation requires the installation of a purlin, for which racks should be mounted on the middle wall or pillars.

Hanging rafters rest only on the walls. This design can be mounted both on the Mauerlat and on thin walls without laying the Mauerlat. In this case, the support for the lower part of the legs is provided by floor beams protruding beyond the plane of the wall on both sides of the building. Hanging rafters are connected by a jumper (tightening, crossbar) which relieves the pushing forces. When covering large purlins, the trusses are reinforced with additional elements to enhance the rigidity of the structure. When installing hanging rafters on a mauerlat, a low-lying tie can serve as a floor beam.

Before installing the rafters, it is necessary to mount the scaffolding. This makes it possible to ensure the necessary safety and convenience of work.

Installation of the upper ends of the rafters

When choosing how to install rafters, it is important to evaluate the complexity of the work and the weight of the rafter structures. If the assembled truss has a relatively light weight, or it is possible to use lifting equipment, then it is easier to assemble the structures on the ground, and then lift and install them on the roof. If the elements of the system are heavy and have to be lifted manually, then the trusses are assembled on the roof. The technology for installing roof trusses is described in the video instructions.

The connection of the upper ends of the rafters can be done in different ways. First of all, this is a butt mount. On the opposing rafter legs, cuts are made at the desired angle. Then the rafters are joined with the resulting ends and attached to two nails. The connection is further reinforced with a wooden or metal overlay.

Attaching the rafter legs with an overlap is done using bolts or studs with wide washers and nuts. In this case, the rafters are in contact with the planes.

If the rafter system is mounted on a wooden house with gables made of timber or logs, it is necessary to install the rafters on the walls using sliding fasteners to avoid deformation of the roof during shrinkage of the structure. Accordingly, in the ridge part, the rafters must be connected in a special way: the rafter legs must be positioned with a gap, and they are fastened together using a special movable metal connecting element.

If there is a ridge beam, installation of rafter trusses on the ground is not required - the rafter legs are installed one at a time and attached to the ridge girder.

The ridge run must be positioned strictly horizontally so that the rafter system evenly distributes the load experienced by the roof.

Methods for installing rafters on walls

The lower ends of the rafters are attached to beams or mauerlats. The hanging rafter trusses, assembled according to a template, rise to the roof. The outer trusses are installed first. It is necessary to make two or three holes in the tightening to attach the rafters to the beams laid on the upper crown of the frame.

If hanging rafters are mounted on a stone building, it is necessary to use special fasteners - the so-called “ruff”, made of durable steel. This fastener is driven into every fourth row of brickwork. Using the loops extending from the ruff, you can secure the beams. It is recommended to use a strong beam as a mauerlat - in this case the load will be evenly transferred to the walls.

On buildings made of brick or other material that is not prone to shrinkage, the rafters should be firmly secured. To do this, a cutout is made in the rafter leg, the lower part of which should lie firmly on the Mauerlat. The rafter is fixed with three nails (two are driven in on both sides at an angle, and the third vertically from above) and tied with wire. A connection using corners and a support bar can also be used to prevent the rafters from shifting.

Proper installation of rafters involves making a fire break in the place where the chimney passes through the roof. If its arrangement involves the installation of a special rafter system, this should be taken into account when installing a shortened rafter leg (from the Mauerlat to the chimney structure). The distance between the structural elements and the pipe must be at least 130 mm.

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The rafter system is the roof frame, which is the basis for laying roofing coverings.

The rafter system is designed to withstand the load of the roof, taking into account natural loads: winds, snow, rain.

The roof option is approved at the design stage.

The purpose of the roof includes several functions: warmth in the house, protection of the premises from natural phenomena, therefore The rafter system needs to be given special attention.

You can read how to calculate the rafter system.

It is customary to classify rafter systems so that the task of choosing a future roofing option is solved easier:

Single-pitch. The simplest ones. More suitable for utility rooms, bathhouses, small private houses, gazebos. Provides for an inclined position of the structure at a slight angle (no more than 25°);
Gable. Used for small houses and country houses. They have the form of a triangle, in which the rafter boards are connected by a beam and are at a certain angle;
Gable broken lines. They have two slopes with a fracture, thanks to which there is an opportunity to increase the attic area;
Three-slope (half-hip). They have two trapezoid-shaped slopes, which are connected by one end triangular slope (hip);
Four-slope (hip). Used for residential buildings, require significant labor costs. They have two end triangular slopes and two trapezoidal ones;
Tent. Used for square-shaped buildings. They consist of four triangular slopes, the upper corner of which is connected in the center of the roof;
Multi-pincer. Consist of trapezoidal or other slopes of various shapes, connected to each other.

The most suitable designs for - and broken gable. There are others, but they are less common and not as practical as the above.

Rafter structures are also classified into:

Hanging. With this type of roof frame due to the lack of load-bearing walls in the room;
Layered. Rafter installation option, providing support on a load-bearing internal wall or support in a building.

When designing a building, the material for the roof frame is calculated based on the intended configuration and load. It’s not difficult to make rafters for yourself, it’s important to approach the matter wisely.

Rafter systems of layered and hanging type

Calculation of the load on the rafters

To correctly calculate the load on the rafters, it is necessary to take into account many factors that can affect the weight of the structure.

Important indicators to consider:

Constant load: includes the mass of the roofing pie and covering material;
The load is temporary: constant and maximum amount of snow, rain, intensity of wind gusts, and in areas with high seismic activity - the effect of storm winds, tornadoes, hurricanes.

In addition, you should keep in mind the weight and strength of the rafter legs, and also pay attention to the fastening of the gable roof rafters and the installation option.

Scheme of rafter systems

The distance between the rafters of a gable roof and the thickness of the rafters

The rafter pitch of a gable roof is the empty space between the rafters. The functionality of the roof depends on the correct calculation of the pitch. As a rule, the step is about a meter.

To more accurately calculate the distance between rafter boards, there is a specific calculation scheme:

Determine the length of the slope.
The length of the slope is divided by the distance between the rafters.
To determine the number of rafters, one is added to the resulting value and rounded up. This is how they determine how many boards are needed for the slope.
The length of the slope is divided by the number of boards to obtain the distance between the rafters.

This calculation is not always final.

Additionally, you should take into account the load of the roofing (its weight), the thickness of the rafters, as well as the dimensions of the rafters for a gable roof.

The thickness of the rafter board largely depends on the covering material:

. Boards are used with a cross-section of 5x20 cm at a pitch of 60 to 90 cm with a sheathing section of 4x5 cm;
. Rafter boards - 5x15 cm, pitch - from 60 cm to 95 cm;
. The section of the board is 6x18 cm or 5x15 cm, the distance between the bars is from 80 cm to 130 cm;
. Rafter cross-section - 5x15 cm, 5x10 cm with pitches from 60 cm to 90 cm;
. The cross-section of the beam is the same as for corrugated sheeting at a pitch of 60-80 cm.

All indicators should be taken into account and the thickness of the rafters should be accurately calculated so that there is no excessive load on the foundation.

Incorrect calculation of the length of the gable roof rafters, as well as incorrect calculation of the pitch indicators, can lead to sagging of the roof.

Installing the rafters of a gable roof with your own hands requires taking into account the weight of the rafter board and all additional fastenings of the structure.

What does the rafter system consist of?

Rafter structure is a complex system and installing a gable roof rafter system is not an easy task. Rafter system consists not only of rafter boards, but also of other additional elements:

Mauerlat. An element that distributes the entire load evenly across the supports;
Run. Boards holding the legs of the rafters together: at the top - a ridge, at the side - a side girder;
Puffs. A connecting beam that prevents the rafter legs from diverging;
Struts, racks. The bars, which fix the stability of the rafters, resting on the bed;
. A lattice made of bars, which is applied perpendicular to the rafters. Transfers the load of the covering material to the rafter frame;
. A connecting beam that serves as a connection between the roof slopes;
Fillies. If the length of the rafter legs is insufficient, they are mounted to form an overhang;
Roof overhang. Extends beyond the bottom line of the slope to prevent precipitation from entering the walls.

The rafter system involves rafters, braces, braces and racks located in the same plane. They are located in such a way that the main load of the roof structure falls vertically on the external load-bearing walls. Therefore, the manufacture of gable roof rafters is a very important process.

What does a gable roof truss system consist of?

Installation of a rafter system with layered rafters

A layered rafter system is used when the span length does not exceed 6.5 meters.

If there are load-bearing structures inside the building, it is possible to install additional racks.

The main support of the rafter legs is the mauerlat.

Mauerlat installation

Before installing the Mauerlat, it is necessary to install an armored belt. It consists of formwork, into which reinforcement is laid and filled with concrete. At the base, when the concrete has not yet hardened, studs are installed, to which the Mauerlat is then attached.

Mauerlat is a beam that is laid on a support (load-bearing wall) and is the base of the rafter frame. A layer of waterproofing material is pre-laid. If the length of the beam is not enough to cover the length of the wall, then it is increased.

Check the equality of the diagonals. A discrepancy of a few centimeters can lead to refurbishment of the frame;
Secure the corners of the Mauerlat;
Attach the Mauerlat using pins or wire. The studs are tightened in two steps, having previously drilled holes for them.

The stability of the roof structure depends on how firmly the Mauerlat is installed.

Therefore, it is necessary to take seriously the attachment of the Mauerlat to the supporting support.

Mauerlat installation

Sill

After the Mauerlat has dried (after 5 days), mark the installation of the plank on the Mauerlat timber: its axis should be equally spaced on each side of the mauerlat beam. The bed is attached to a two-layer waterproofing layer with anchor bolts. The bench should be secured to the wall from the inside with twisted wire or staples. Next, markings are made for installing the rafters.

Installation of a gable roof rafter system

The supporting points of layered rafters are the walls and racks inside the frame. The rafters are mounted with hinged fastening units. When using sliders for fastening, a slight lowering of the roof frame is ensured in the first years of the roof's service.

This installation method is necessary to prevent distortions, since in the first years the building settles a little.

The rafter beams should be secured either by installing them in prepared grooves and strengthening them with fasteners, or by attaching board overlays.

Installation of rafters

Ridge knot

The rafters are connected end-to-end by cutting the edge of the beam so that the angle when connecting the opposite beams corresponds to the angle of the slope. They hammer the rafters under the ridge with nails. An option is possible in which the beams are connected with bolts, nails or pins, that is, with an overlap.

If necessary (if provided for by the project), a cut is made in the rafter beams to attach the ridge beam (purlin).

Ridge knot

Racks

The racks are attached with a short span - in the center, on the sides and in the center - with a wider roof base. The fastening is carried out vertically from the ridge to the inner wall.

Run

Purlin - a connecting beam for securing rafter legs. Attaches with bolts or brackets to the rack.

Filly installation

The final stage of installation of the layered system is the installation of fillets with a short length of rafter legs for the overhang. To install the canopy, it is necessary to install additional small rafter boards.

Installation of a rafter system with layered rafters

DIY gable roof rafter system: installation with hanging rafters

Rafter system, equipped with hanging rafters, is a triangular structure, where the sides are rafters, and the base is a tie connected to the lower heels of the rafters.

Installation of a hanging type rafter frame can be done without installing a Mauerlat: a board that is fixed to a two-layer waterproofing can replace it.

If the structure has a large span, then struts, headstocks, and crossbars are attached to it.

There are no racks in the hanging system.

Puffs

The tie is the longest beam of the roof frame. To prevent it from sagging, it is necessary to attach headstocks - boards that are attached to the top of the structure on one side, and to the tie on the other. Fastened with bolts or wooden plates. Using threaded clamps, you can adjust the sagging tightening.

Construction of the rafter system

Installation of strut beams

The headstock can be complemented by strutted beams, forming a rhombus, where two struts are the lower sides, and the rafter boards are the upper ones, the upper corner being the ridge. Thus, the struts rest against the headstock, distributing the load.

Strut beams

Rafters

The rafters of a hanging structure are mounted similarly to a layered one. When installing attics, the tie is installed closer to the ridge, providing more space under the ceiling. In this case, the tightening is secured by cutting and bolting.

ATTENTION!

When installing a hanging system, a prerequisite for installation is the accuracy of calculations and the strength of the rafters and tightening.

The presence of errors leads to displacement of the axes of system elements, which ensures distortion of the structure.

This photo will tell you how to install rafters for a gable roof:

Installation of rafters

Hanging rafters

How to strengthen the rafters of a gable roof

It is necessary to strengthen the rafters of a gable roof when the load calculation is incorrect or frame defects are detected.

Strengthening can be done using:

Beams, which are installed to transfer the load to them;
Installation of struts with an inclined mount with an emphasis on the bed;
Application of double-sided slats;
Increasing the cross-section of rafter beams in the place of supports on the strut by applying sheathing from boards with nails or bolts;
Wall made of boards, which are attached to the rafters in places where snow accumulation is expected to increase the load-bearing capacity of the rafters.

You can resort to strengthening the mauerlat beam and the base of the rafter beam. Due to increased humidity and reduced ventilation, these parts of the frame are more susceptible to rotting, so when arranging the roof special attention needs to be paid

Is it time to install a roof? The very first thing you need to do is install the rafter system. This work is very important and complex, and therefore you need to carefully read our advice.

A little theory - what do you need to know about the rafter system?

First of all, we need to talk about the types of rafter systems and their characteristics. So, this system consists of the following elements:

rafter legs;
racks and vertical supports;
struts;
puffs - an element that connects the rafter legs.

You should also distinguish between rafters by type. Rafter systems are divided into:

Layered. They should be used if the building has internal partitions or other supports. In this case, the “legs” of the structure must rest on both the external and internal walls.
Hanging - in which the “legs” of the structure rest only on the outer walls. A distinctive feature of this design is that its construction requires tightening due to high thrust loads.

Several important technical characteristics

When choosing a method for installing rafters, it is necessary to assess the complexity of the work and the weight of the future structure. If the assembled product is lightweight or you can bring special lifting equipment to the site, then it is best to assemble the rafters on the ground, and then lift it to the roof of the building, where you can do all the other work. If the structure is heavy, then it will have to be assembled directly on the roof - this is easier and safer.

It is very important to connect the upper parts of the rafters correctly. This work can be done using several methods. First of all, butt jointing, when cuts are made on the opposite rafter legs at the required angle. Next, the rafters need to be joined along the resulting ends and secured with several nails. For a safer connection, secure the products with a metal pad.

You can attach the rafter legs with an overlap - in this case, the structural elements touch each other with planes. If you are going to make a rafter system in a house with fronts that are made of logs, then the rafters must be installed on the walls using the sliding fastening method. Thanks to this, you will be able to avoid deformation of the roof in the event of shrinkage of the house.

If you decide to use this method, then you need to keep in mind that it is quite difficult to do it yourself. Fastening is done as follows: the “legs” of the rafters must be placed with a gap, fastening them together using a specialized movable metal element. Now we proceed to the actual construction of the rafter system with our own hands.

Mauerlat - what is it and what is it for?

The construction of the rafter system must begin with the installation of the Mauerlat - this is the basis for the future structure. Mauerlat is a log or beam that is fastened along the entire perimeter of the external walls. Undoubtedly, it is possible to make a structure without a Mauerlat, but building such a structure with your own hands will be quite difficult and even risky. It is very important to follow all the recommendations exactly so that the base for the rafter system 100% fulfills the functions assigned to it.

Important Tips:

Before laying the Mauerlat, you need to insulate the walls using a suitable waterproof material. To save money, you can put several layers of roofing felt.
Installation of logs is carried out on a reinforced belt with a slight indentation from the edges of the walls.
It is best to choose logs of antiseptic wood with a cross section of 10*15 cm.

To make it easier to do the work yourself, the beams must first be laid out from one front to the other along the entire length of the wall. After this, you can take measurements: lay out the beams level, making sure the distance between them is even. Next you can attach the beams to the walls. As we have already said, it is preferable to carry out installation on a reinforced belt, using anchor bolts as fastening products - it is better to fasten them when pouring the reinforced belt. Also, do not forget to drill holes in the beam itself.

Important: if you want to achieve a perfectly even position of the bolts, before pouring the “belt”, attach the board to the bolts and give the fasteners a vertical position using a square.

We place the base prepared with our own hands on stands consisting of planks, after which we carefully lower the beams onto the bolts, removing a plank each time. Finally, screw the washer onto the bolt. Now it’s time to learn how to make a rafter system with your own hands.

Do-it-yourself rafter system installation

We have already talked about installing the Mauerlat. Now it’s time to move on to the main point of installing the rafter system - the installation of floor beams and ridge beams. But first things first. Floor beams are beams with a cross section of 20*10 or 15*10 cm. The length of the products should be such that when laid on the walls, the beams form a projection that will correspond to the width of the cornice.

In simple terms, the beams must extend beyond the walls at a certain distance. The bars are installed in one direction, leaving an equal distance between them.

To avoid errors while performing work, you should follow a clear sequence of actions:

We install the boards with our own hands, retreating from the edge of the walls by an average of half a meter.
We stretch a cord between the beams - it will serve as a kind of “beacon” for installing the next beams.
The distance between the “legs” of the structure must be selected based on the cross-section of the rafters. So, if you decide to choose “floor” boards measuring 5*15 cm, then the step should be approximately 60 cm. It is worth noting that this will greatly simplify all further work. And all thanks to the fact that the width is most often 60 cm, which means there will be no need to trim anything.
We proceed to the installation of transverse beams, one part of which should be in contact with the outer beam, and the second part should extend beyond the walls. The gap between such jumpers should be about 1 m.
We attract the beams to the base (mauerlat) using nails, you can also use self-tapping screws and steel corners (for reliability).

To make your work as convenient as possible during the construction of the rafter system with your own hands, lay ordinary boards on the beams.

Now it's time to talk about installing ridge beams. This stage consists of several steps:

Installation of auxiliary racks, which are U-shaped struts made of wood. Professional experts advise that the height of the struts be equal to the height of the first floor.
We assemble the racks at opposite ends of the structure and install intermediate beams, maintaining a step of 2.5 meters.
After installing the racks, we place a ridge beam on top (a wooden board with a cross-section of 5*20 cm). Secure the structure with self-tapping screws.

Since the rafters must be the same length, it is advisable to make a template in advance to determine the length. To do this, take one board measuring 2.5*15 cm, apply it to the beam and to the ridge, and put marks at the points of contact and saw off the unnecessary part - you can make blanks using this template. However, it is worth noting that not everyone can achieve perfect evenness, so be prepared for the fact that during the installation process you will have to use a saw more than once.

If you neglect this advice, the ridge may bend, which may make the structure not so reliable.

After you have installed the rafter system, you need to waterproof it, create a sheathing and cover the structure with roofing material. Now you know how to assemble the rafter system - the roof is almost ready. We hope our tips will help even you do the job yourself.

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 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

Choosing a rafter system is a crucial step that requires knowledge of the design of each type of roof. Rafters can be:

Layered rafters supported by a ridge girder and a mauerlat. They are used in the construction of a single-pitched, simple gable roof, and also as one of the elements of a hip and sloping mansard roof.
Sliding rafters are a type of layered rafters used for wooden buildings that exhibit high 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 tied together with crossbars or tie rods, usually used in the construction of a simple gable roof, as well as as the top rafters of an attic roof. In a hanging rafter system, there is no ridge purlin, and in the upper part the symmetrical rafter legs rest directly on each other.
Sloping rafters, otherwise called corner or diagonal. They are used to make three-pitched or hipped roofs, as well as for roofs with complex geometry.

Elements of the rafter system

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

Mauerlat is a beam fixed to the upper plane of the walls along the perimeter of the entire house;
Bedding - support beams laid on internal load-bearing partitions or columns;
Floor beams of the upper floor;
Racks and supports;
Purlins are horizontal supporting elements laid along the axis of the roof on racks.

The roof truss consists of the following elements:

Rafter legs - boards or timber that form the contour of the roof and are laid at a certain pitch;
Tightenings or crossbars are horizontal elements that tighten paired rafter legs together;
Struts - supports placed at an angle and supporting the rafter legs;
Fillers are boards attached to the lower end of the rafters and forming roof overhangs;

Rafts are short rafters resting on diagonal rafters in a hip roof.

All these elements in private construction are usually made of wood - timber or naturally dried softwood boards. The wood is impregnated with an antiseptic, which extends its service life. The thickness and cross-section of the elements is determined by calculation.

Technology for making layered rafters

Before construction begins, it is necessary to sketch the roof and calculate its dimensions. The cross-section and pitch of the rafters, as well as the need to install additional supports and struts, are also determined by calculation.
Supporting elements are laid and positioned: mauerlat, floor beams and beams, racks, ridge and intermediate purlins. These operations are described in detail in articles devoted to various types of roofs:
Make a rafter template. To do this, take a board with a width corresponding to the estimated length of the rafters, with the same width, but with less thickness - it is lighter and easier to precisely adjust to the location. The board is applied to the installation site of the outer rafter with one end to the ridge girder and the other to the mauerlat.
At the top of the template, mark the top notch. The shape of the cut should be such that the board rests on the ridge girder and at the same time fits tightly to the opposite rafter. The depth of the cut should be no more than 1/3 of the width of the board.
After cutting out the top cut, the template is once again applied in place and the bottom cut is marked - it should rest on the Mauerlat without leaving large gaps. The end of the template is filed at an angle so that the cut is in a vertical plane.
The resulting template is applied to the installation site of all rafter legs, checking whether adjustment will be necessary in place. If the template fits perfectly (which rarely happens), you can immediately make the required number of rafter legs. If adjustments to the bottom cut are needed, then only the upper part of each rafter is cut out using templates, and the bottom cut is made in place each time.
The rafters are installed at the calculated step. Typically it ranges from 50 to 120 cm and depends on the type of roofing, namely its weight, and the expected snow load. The heaviest coverings are slate and ceramic tiles, but they are rarely used nowadays. More often, the choice is made in favor of more modern, lightweight and reliable materials: metal tiles, ondulin, soft roofing. For them, the rafter pitch can be chosen to be about 100 cm without performing complex calculations.
First, install the rafters on the gable side. The rafter leg is supported on the ridge purlin and the Mauerlat and secured to two nails 100-150 mm in each fastening point. Having installed the rafter pair, they additionally fasten it: in the upper part with the help of metal plates and screws on one side and corners with a stiffener on the other, in the lower part with staples or also with corners.
After installing the rafters from both gables of the roof, string is pulled between them and the remaining rafters are aligned along it. The rafters are fastened in the same way.
Install struts if the calculation results require it. The struts are made of the same material as the rafters. Apply a board of suitable length at the desired angle to the rafters and mark the bottom cut. It is important to consider what the strut will rest on: the floor beam or the beam; the shape of the bottom cut depends on this. After completing the bottom cut, the strut is placed in place and the cutting line along the rafters is marked. The prepared strut is placed between the beams and rafters and secured with metal plates or corners.

Installation of roof struts

Technology for making hip diagonal rafters

Since the rafters for a hip roof are installed diagonally, the usual methods of fastening them are not suitable. In addition, the load on diagonal rafters is much higher than on layered or hanging ones, so the material for their implementation must have a larger cross-section. You can use timber with a thickness of 100 mm or more, but practice shows that it is more convenient to make these rafters from two folded and fastened boards of standard thickness.
The upper end of the diagonal rafters rests on the racks, and 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 made 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 made with oblique cuts, then the second, in a mirror image.
The boards are pulled together using screws, nails or studs. The hip rafters are secured using overlays and self-tapping screws.

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

When making any rafter system with your own hands, it is important to carefully secure all components and connections and remember that the roof is the main protection of your home 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.

Construction of a reliable rafter system is one of the most difficult tasks when constructing the roof of a country house, cottage or garage. And yet, do not rush to give up - today we will refute the popular belief that such work is beyond the capabilities of a beginner. Knowing the rules for calculating, sawing and installing a roofing frame, you can build a roof no worse than specialists. In turn, we will try not only to talk about the structure, design and construction features of various types of rafter systems, but also share the secrets of experienced craftsmen.

What is called a rafter system and how is it structured?

Any, even the most shabby roof is based on a strong power frame called a rafter system. The rigidity of the roof, and therefore its ability to withstand even the strongest wind and snow loads, depends on how correctly this structure is installed.

The rafter system is the roof’s power frame, which absorbs all wind and snow loads

The best material for making rafters (trusses) is considered to be timber or a thick board made of coniferous wood. And there is an explanation for this - pine or spruce lumber is relatively light in weight, and the presence of natural resins makes it quite durable. Even if the timber has a slight residual moisture, it will not move when dried, which is no less important a factor than ease of use and long service life.

Depending on the size of the roof, the supporting elements of the structure can have a cross-section from 50x100 mm to 200x200 mm or more. In addition, the length of the roof directly affects the number of rafters, because they are installed in small increments - from 60 cm to 1.2 m.

Structural elements of the rafter system

The main requirement for a wooden frame is the ability to withstand bending and torsion. For this reason, a triangle shape is best for timber frame trusses. Moreover, they can consist of several parts:

rafter legs - the base of the roof frame, which has the greatest influence on the size and geometry of the slopes;
crossbars (bolts) - boards that tie together a pair of rafter legs;
purlins are transversely installed beams, due to which the rafters are connected into a single structure;
racks - vertical supports that serve to support rafter legs or prevent purlins from deflecting;
struts - the same racks, only placed at an angle to the vertical;
beds - boards attached to the attic floor on which supports are installed;
Mauerlat - a support beam installed on load-bearing walls, to which the lower parts of the rafter legs are attached;
fillies - pieces of timber or boards that are nailed to the lower ends of the trusses and are used to arrange roof overhangs.

Additional elements of the rafter system make the roof frame more durable, rigid and stable

When choosing a roof frame design, it is important to find that golden mean that will allow you to obtain a strong and reliable structure at minimal cost. For this reason, you can deviate a little from the established canons, if the matter does not concern the rigidity of the entire structure. For example, it is quite possible to do without fillies, and form the eaves overhang using longer rafter legs. Or use not a solid Mauerlat, but pieces of timber laid only in the places where the rafter legs are attached - it all depends on the engineering ingenuity and experience of the roofer.

Rafter classification

Depending on the roof structure and the purpose of the attic space, a wooden frame can consist of several types of rafters:

Features and types of rafter systems

To make an informed choice, you need to understand the features of various types of rafter systems and know the strengths and weaknesses of each design.

Roof frame with hanging rafters

Since the principle of fastening hanging rafters does not require additional support points, this design is used for buildings no more than 6 m wide. Installation of unsupported trusses involves fastening each pair of legs to opposite main walls, while their upper parts are fixed directly to the ridge girder.

A roof frame with hanging rafters transfers only vertical forces to the walls, therefore it has simpler attachment points to load-bearing walls

During operation, a force acts on the hanging rafters, tending to push the structure apart. To compensate for the bursting force, a crossbar made of wooden beams or a metal profile pipe is installed between the rafter legs. If the attic space will be used for household purposes, then the upper lintel is secured as close to the ridge as possible, and the lower edges of the pairs of rafter legs are connected with ties. This scheme allows you to increase the useful height of the attic without at all reducing the strength of the frame. By the way, if the lower lintels are made of timber with a cross-section of more than 100x100 mm, then they can also be used as load-bearing beams. It is necessary to ensure a reliable connection between the tie rods and the rafter legs, since significant pushing forces are also applied to the place where they are attached.

Roof with layered rafters

Layered rafters require the installation of at least one support, so they are used for buildings with internal load-bearing walls. The maximum length of a single span should not exceed 6.5 m, otherwise the strength and rigidity of the roof frame will suffer. To increase the width of the roof, the rafter system is reinforced with intermediate supports. Even one additional post allows you to increase the width of the roof up to 12 m, and two - by more than 15 m.

A system with layered rafters is an ideal option when you need to build a large roof width

The stability of layered trusses can be increased by using a sub-rafter frame with purlins, racks and struts. In addition, this rafter system requires much lower lumber costs. The versatility, strength and cost-effectiveness have long been appreciated by both construction companies and individual developers, most often using roofing structures with layered beams in their projects.

Combined options

Today, the roofs of country houses amaze with the elegance of their design, whimsical shapes and variety of configurations. Such complex structures can be built in only one way - by combining both types of rafter systems in one frame.

The combination of layered and hanging trusses allows you to obtain a rafter system of any configuration

Even for the construction of not the most complex sloping roofs, both rafter systems are used at once. Right-angled triangles located on the sides are layered rafter structures. And they are connected due to the upper tie, which at the same time plays the role of a tightening for the upper hanging rafters.

Procedure and rules for installing roof frames

Since two types of roof frames are used in the construction of roofs, we will consider the installation technology of each structure separately. However, before starting construction work, it is necessary to study methods of fastening structural elements to each other.

Construction of a roof with hanging rafters

It was already mentioned above that hanging rafters are most often used in the construction of small or undemanding buildings. In this case, a log house is an almost ideal option, since you can do without a mauerlat. The lower part of the rafter legs is attached to the upper crown or the edges of the ceiling beams (matits) protruding beyond the perimeter of the walls. In the latter case, the tie must be moved upward - this will allow the timber to be placed over the finishing log and make the attic more comfortable.

To increase the height of the attic space, the tie should be installed as close to the top of the roof as possible

Preparatory work

The geometry of the slopes depends on how well the beams for the rafters are prepared. A cord stretched between nails driven into the outer beams will help to level the supporting surfaces.

It is necessary to cut down the slab, obtaining flat areas for installing trusses. After this, you should definitely check how accurately they lie in the same plane. This can be done with the help of a long, even rod and a level.
Before installing the trusses, the supporting surfaces are aligned with the cord
After removing excess wood, you need to make a recess in each beam for the rafter tenon. You can draw the locations of future nests using the same nails and cord as in the previous case. Although recesses for the rafters can be made both before and after the manufacture of the trusses, experts advise doing them first - this will allow fitting to be carried out with higher accuracy and convenience.
The method of fastening the rafters depends on many factors - the type of support beams, their cross-section, features of the roof overhang, etc.
Professional roofers recommend installing an additional guide - a vertical strip - in the center of the span of each gable. One of its sides is used as an axis of symmetry, which will make it possible to ensure strict adherence to the geometry of the structure.
In order to simplify the process of marking and installing the roof frame, use vertical slats installed along the center line of the roof

Making rafters

In order for the rafters to have the same dimensions and configuration, they are made according to a pre-made template. To make it, we suggest using the following instructions:

Take two shawl boards and bolt them together to create a structure similar to a drop-down compass. The threaded connection should not be overtightened - the structure should rotate around the top. Be sure to check that the slats are 10–15 cm longer than the rafters - this will be needed to take into account the height of the abutment tooth.
The simplest template allows you to get roof trusses of the same size and configuration
Make two marks on the staff installed as a guide. The lower one should correspond to the height of the rafter system, and the upper one should be spaced from it to the height of the mounting protrusion.
Place the template on the matrix so that the corners of the boards rest against the recesses for the rafter teeth.
In order for the structure to successfully cope with thrust loads, the thrust tooth at the end of the rafter leg is inserted into a recess on the floor beam
Align the axis of rotation of the “compass” with the top mark on the rail and set the height of the tenon from the lower corners of the jig.
Lower the template down and cut the teeth along the drawn line. After this, lift the device onto the roof and insert the spikes into the sockets on the motherboard. Check that the sample axis coincides with the bottom mark on the vertical staff. If necessary, move the bolt in the desired direction and fix the angle between the boards with a cross member.
Several methods are used to fasten trusses - it all depends on the type of support beams, the design of the roof frame and the cross-section of its elements
Having adjusted the template to the height, apply vertical joining lines to each board. Finally, measure the length of the transom and use scrap boards to create a template for making caps for the tops of the trusses.
To attach the crossbar to the rafters, overlays from sections of inch boards are used

After the template is lowered to the ground, it is disassembled and cuts are made according to the applied markings. In addition, a separate pattern is constructed according to which the ends of the rafter legs will be cut. The manufacture and assembly of hanging rafters is most often done below, lifting the finished structures onto the roof. If the weight and dimensions of the assembled trusses do not allow them to be pulled up manually, then the assembly is carried out on site. In this case, the components of the rafter system are fixed with nails ranging in size from 100 to 200 mm.

How to install rafters on a roof

In order to lift and install the trusses, you will need the help of at least one person. Trying and plumbing the rafters alone is an extremely difficult task - you will have to attach them to the struts more than once and descend from the roof many times to check the deviation from the vertical plane.

With the help of a rafter tooth, it is possible to obtain such a reliable connection that only one nail can be used for final fixation

When lifting the assembled rafters upward, first mount the outer structural elements, and then the central and intermediate ones. To strengthen the structure, a support is installed under each leg:

Having aligned the hanging rafters to the level, they are fixed with temporary spacers. After this, the lower ends of the beams are nailed to the matrix or floor beams.

Various temporary structures significantly simplify the process of installing rafters at level

There is no need to resort to newfangled methods of fixation using various corners and perforated plates. The reliable “old-fashioned” method of fastening using nails 200 mm long or construction staples will be much better both in terms of strength and reliability, and in cost. At this stage, you don’t have to worry about the structure looking flimsy.. After the remaining elements of the rafter system are installed and the sheathing is completed, the structure will acquire the necessary rigidity and stability.

Video: making and installing hanging rafters with your own hands

Features of installation of layered rafters

The process of manufacturing and installing layered rafters is generally very similar to the construction of a suspended roof frame. The main difference is at the top point and is due to the fact that the tops of the layered beams rest on the ridge girder. In this case, the connection with the latter is performed in several ways:

simple adjoining apart (in parallel to each other);
with making a vertical joint (the same as when connecting the paired legs of a hanging truss);
by tightly fitting the beams to the upper beam (using a vertical cut or notch).

If the design of the wooden frame provides for the support of trusses on the side purlin, then the rafters are connected end-to-end, and in the places adjacent to the purlin, recesses are made.

To fasten layered rafters, use nails, construction staples or linings made of wood and metal

To ensure structural strength, the notches should not be too deep. Experts recommend making recesses no more than a quarter of the thickness of the timber or a third of the width of the board.

Individual developers most often resort to installing rafters in the following way:

the upper part rests on the ridge beam through a vertical cut;
From below, the rafter legs are held in place by a corner notch.

It is convenient to use a construction square for marking. After the scale is selected, the values of the slope rise and half the span are plotted on the sides of the right triangle. Thanks to this, it will be possible to obtain the slope angle of the slope without resorting to mathematical calculations.

To make rafters, we suggest using the most convenient method:

At first glance, this method is very tricky. However, even a quick glance at the instructions provided is enough to master it perfectly. Of course, you can set aside the necessary distances and make markings using a calculation method, but it will be much easier to get confused when calculating angles and distances.

It should be remembered that the cuts made in the rafter legs must be absolutely identical, otherwise the roof slope will be uneven. To do this, you can use a wooden block as a template. It is only important that its thickness does not exceed 1/3 of the thickness of the workpiece.

For the most common slope angles, there are templates, the configuration of which has already been calculated by professionals. By using one of these patterns, you can significantly simplify the task of marking the corners of notches.

Templates with marked notch angles allow you to simplify the process of making rafters

Assembly and installation of a layered structure

Video: installation of rafter legs of a layered roofing system

Methods for connecting rafter joists

When choosing timber for large roof trusses, you have to look for a reasonable compromise between the length and thickness of the rafters. The reason for this is the features of the standard range of lumber, in which longer beams have an increased cross-section. On the other hand, their use is not always justified both technologically and due to the increased cost of the structure. The way out of this situation is to lengthen the rafter legs by splicing. The rigidity and mechanical strength of the beam depends on how correctly the joint is made, so the connection is made strictly according to a certain method.

Oblique cutting method

The method of splicing with an oblique cut is that inclined cuts (cuts) are formed on the mating parts of the beams. They should be carried out especially carefully - after combining both parts of the beam, there should be no gaps left, otherwise deformation will appear at the junction.

When splicing with an oblique cut, there should be no gaps or gaps between the mating surfaces, which could weaken the rafter and cause its deformation.

When making cuts, leave a small transverse section with a height of at least 15% of the rafter thickness - the presence of the end part will make the connection more durable. To calculate the optimal length of an oblique cut, it is necessary to multiply the height of the beam at the cutting site by two. The truss is fastened with nails, clamps or bolted connections.

Connection by rallying

To lengthen the rafter using the joining (stitching) method, the edges of the boards are overlapped and a stand is installed in the center of the junction area. The elements are fastened using nails, which are driven in according to a certain pattern:

along the edges of the ends - every 45–90 mm;
along the edges of the sewn boards - in a zigzag pattern, in increments of 50 cm.

Connecting boards by joining allows you to do without additional pads, but requires the installation of additional support in the center of the junction area

In order for the beam to successfully cope with operational loads after joining, the length of the joining section (T) is calculated using the formula T = 0.42 × L, where L is the length of the overlapped span.

Frontal support

The connection by frontal extension consists in the fact that the edges of the individual parts of the rafters are carefully trimmed and butted together. For fastening, lumber linings with a thickness of at least 1/3 of the section of the main beam are used. The length of the overlays is determined by the formula L = 3 × h, where h is the width of the board.

When splicing with a frontal stop, a monolithic structure will be obtained only with the correct placement of fasteners

All parts are fixed using nails or bolted connections. In the first case, nails are driven in two parallel rows, trying to place the fasteners in a zigzag pattern. The threaded connection is made in a checkerboard pattern, determining the number of bolts depending on the length of the linings.

Composite length extension

To build up a rafter leg, it is not at all necessary to use both parts of the same section. With a composite extension, a single element can be lengthened by using two boards that are sewn onto its side planes. The resulting gap is filled with scraps of lumber of length l = 2 × h in increments of L = 7 × h, where h, as before, is the thickness of the element being extended.

Composite extension of rafters allows you to attach crossbars, supports and other structural elements in the most convenient way

Expert advice on making rafters and assembling roof frames

When starting to independently design and install a rafter system, be sure to consult with experienced roofers regarding the specifics of constructing roofs in your area. Perhaps their advice will save you from trouble and help you save time and money. In turn, we offer several recommendations that will help make the structure more reliable and durable:

If a beam of minimal cross-section is used to make the mauerlat or top trim, then cuts can weaken it. For this reason, cutouts should only be made at the lower ends of the rafter legs.
To prevent precipitation from falling on the wooden frame and walls of the house, the roof must have an overhang. To equip it, use pieces of timber (fillies), which increase the length of the rafter legs, or make trusses of increased size.
Connections using cuts at an angle of 90 o cannot be used.- in this case, the resistance of the element to load forces is significantly reduced.
If the elements of the rafter system are connected with threaded fasteners, then wide washers or metal plates are installed under the heads of the bolts and nuts. Thanks to the increased area, the fasteners will not be pressed into the wood.
All wooden parts of the structure must be thoroughly impregnated with antiseptic and fire retardant.
When determining the cross-section of the puffs, they are guided by how close they will be to the ridge. The shorter the connecting beam, the greater the load it bears and the more powerful the lumber and bolted fasteners are used.
When determining the cross-section of the timber for the manufacture of rafters, do not forget to take into account the thickness of the thermal insulation layer.

Video: recommendations from experts on the correct connection of roof frame elements

https://youtube.com/watch?v=GbTAu5-flfs

Modern materials and technologies make it possible to build a roof of any configuration and purpose. Given such diversity, it is simply impossible to consider all options in detail within one article. However, based on the basic principles of construction discussed here, you can easily cope with the most complex structure. The main thing is to pay attention to detail, be attentive and careful in your work. And then the roof will not only be a reliable functional superstructure, but also a true decoration of your home.

Thanks to my varied hobbies, I write on various topics, but my favorites are engineering, technology and construction. Perhaps because I know many nuances in these areas, not only theoretically, as a result of studying at a technical university and graduate school, but also from the practical side, since I try to do everything with my own hands.