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

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

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

But then be prepared for the following disadvantages:

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

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

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

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

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

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

How to draw up a project for a future roof?

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

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

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

The angle of inclination of a gable roof is made from 5° to 90°. But the most proven and standard option– 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 regulation of heat exchange. But when the under-roof space is planned to be residential, attic, they initially plan a so-called sloping gable roof. Its difference is that the slopes in the middle have a kind of kink, which changes their angle to a steeper one. This design is quite suitable both for arranging an attic and for protecting the entire house from bad weather.

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

Constant and variable roof loads

The same loads determine what rafter pitch you need for your gable roof. Pick up required section This table will help you with rafter legs:

Indicators of rafters for deflection

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

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

Reinforcing elements for rafters

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

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

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

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

Determining the type of roof: cold or warm?

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

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

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

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

Determine the type of rafter system: layered or hanging?

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

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

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

Selecting material for rafters

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

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

Dry board: economical option

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

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

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

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

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

Durable metal: resists moisture

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

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

Beams: the benefits of high-quality wood

The timber is more durable, but is bad because it has heavy weight and in the places of fastenings it is necessary to make cuts. For the log this is not only a problem, but also some loss bearing capacity such a rafter leg. But so far this material is the most popular for making rafters.

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

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

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

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

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

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

Treatment with antiseptics and propylents

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

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

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

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

Video tip on the topic of processing rafters:

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

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

Making the correct cuts on the rafters

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

And follow these instructions:

You will have to tinker with the rigid mount:

If we're talking about about moving parts, then follow this principle:

In practice, everything is actually simple:

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

How to assemble a rafter system?

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

Build on the ground or on the roof?

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

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

Attention to strength - rules for increasing length

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

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

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

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

Preparing roof trusses

Fasten rafters needed using:

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

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

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

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 are making the roof, connect the beams with cut planes and secure with two nails. Cover the joint with a wooden cover or metal plate.

Another useful master class:

Lifting and installation of finished trusses

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

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

The rest is a matter of technique:

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, this issue is given Special attention. 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 means required amount 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.

Preparation of material

Installing rafters with your own hands requires not only knowledge of the process technology, but also proper preparation wooden elements systems 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, and 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 section of 150×150 mm. Top part layered rafters rest 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. About installation technology roof trusses explained in the video instructions.

The connection of the upper ends of the rafters can be done different ways. First of all, this is a butt mount. On the opposite rafter legs, cuts are made under the right 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 wooden house with gables made of timber or logs, it is necessary to install 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.

In the presence of 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 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 roof passes chimney. 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). Between structural elements and the pipe the distance must be at least 130 mm.

+10

Rafter system- 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:

1. 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.
2. Sliding rafters are a type of layered rafters used for wooden buildings giving 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.
3. 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.
4. Sloping rafters, otherwise called corner or diagonal. Used to perform three-slope or hipped roof, 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 the inner load-bearing partitions or columns;
• Floor beams of the upper floor;
• Racks and supports;
• Purlins – 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

1. 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.
2. Supporting elements are laid and positioned: mauerlat, floor beams and beams, racks, ridge and intermediate purlins. These operations are described in detail in articles dedicated to various types roofs:
3. 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.
4. 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.
5. 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.

   

6. 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.
7. The rafters are installed at the calculated step. Typically it ranges from 50 to 120 cm and depends on the type of roofing covering, namely its severity, and the expected snow load. The heaviest coverings are slate and ceramic tiles, but they are currently rarely used. More often, the choice is made in favor of more modern, lightweight and reliable materials: metal tiles, ondulin, soft roof. For them, the rafter pitch can be chosen to be about 100 cm without performing complex calculations.
8. 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 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 on the corners.

   

9. 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.

   

10. 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

1. Since the rafters are for hip roof install diagonally usual ways their fastenings 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.
2. 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.
3. 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.

The most important and difficult stage is the installation of the rafter system. The operation of the roof is associated with constant and periodic loads in the form of snow or gusts of wind.

To figure out how to make a rafter system with your own hands, you need to decide on its components. Rafter frame used for any type of roof, it differs in the level of complexity during installation. Single-pitch and gable roofs are considered simple designs. Hip or hip roofs provide a reliable roof, but are difficult to calculate and install rafters.

When choosing the size of material for the frame, many factors must be taken into account. The cross-section of the rafters and load-bearing base must withstand the weight of the roof, climatic loads, and the weight of the devices installed on the roof (if any are installed).

Essential elements

For the skeleton gable roof The following elements are required:

1. Mauerlat is a beam of considerable size 150×150 mm or 200×200 mm, which is laid and secured around the perimeter of the walls. It connects the truss system and the building structure in general structure, distributes the load on the walls.
2. The ridge is the highest point of the roof at which the rafter legs are connected. The longitudinal beam helps to hold the structure and ensures stability under wind loads.
3. Rafters - made of boards with a cross-section of 70×150 mm, they bear the entire load. Rafter legs are created from the boards, which are attached in increments of at least 60 cm.
4. Lezhen – a beam located parallel to the ridge. Its dimensions are equal to the Mauerlat. The bench is a support for racks and other elements.
5. Tie-downs are crossbars made of boards connecting the rafter leg.
6. Racks are bars installed vertically; they are installed to support the ridge girder.
7. Overhangs are parts of the rafters that protrude beyond the walls. They allow precipitation to be removed from the house.
8. Struts - serve to strengthen the rafters, allowing you to create durable structures.
9. Lathing - boards necessary for tying the rafters and laying them roofing material.
10. Fillies - when the length of the rafters is not enough for an overhang, additional boards are filled with “fillies”.

Types of rafter systems

Several types of rafter systems are used to construct the frame of a gable roof.

Layered - the choice of this design implies the presence of a support in the form of a wall in the center of the building. They receive three points of support and experience only bending load. The upper part of the rafter leg rests on the purlin, and the lower part on the mauerlat. This system allows the use of thinner lumber, lower costs and lighter weight construction.

Hanging - rafter legs rest only on the walls, so they experience a large load. To add strength, they are connected by tightening. Such rafters are usually assembled at the bottom and delivered directly for installation.

Complex roof shapes require non-standard solutions, for them, combinations of hanging and layered rafters are used.

When installing a hipped roof, the basis of the frame is the diagonal rafters connecting the ridge girder and the corners of the building. They are supported by rafts - short rafters, which, together with ordinary side rafters, form the basis of the roof slope.

Preparation of material

The service life of the rafter structure depends on the quality of the lumber and its processing. For structural elements, it is necessary to select dry wood with a moisture level below 22%. It should be smooth and without knots. Before installation, all parts are treated with two layers of antiseptic and a fire retardant. When processing, you should use a brush rather than a spray, then the composition will be better absorbed. When choosing lumber, preference is given to coniferous wood.

Fastening

The durability of the structure will be ensured by proper installation of the rafter system with your own hands. To connect the rafters use different kinds fastenings: staples, nails, shaped steel parts - corners and plates, which are screwed with self-tapping screws.

Rafter section

The dimensions of the timber used for rafters are influenced by:

• span size;
• impact of climatic features;
• the angle of the slope and the step of fastening the rafter legs.

The constant load is calculated from the total weight of the roofing material, insulation and waterproofing. As the distance between the rafters increases, material of a larger cross-section is required. The wind and snow load coefficient must be included when calculating the cross-section. Common rafter sizes are 50x150 mm and 60x200 mm.

Rafter length

The base of a symmetrical gable roof is an isosceles triangle. Knowing the height of the ridge, you can calculate the length of the rafter using the Pythagorean theorem. In this case, it is the hypotenuse, and half the width of the queen and the height of the roof are the legs.

Installation of rafters

The first step in installing a rafter system for any type of roof is laying and fastening the Mauerlat. Waterproofing in the form of roofing material must be laid underneath it. This beam requires drilling holes along the length into which studs embedded in the masonry are inserted and tightened with a nut.

Having created the basis for the frame, a template is made according to which all the rafter legs for the hanging system are assembled on the ground. To create a sample, take two thin boards equal in length to the rafters and fasten them with a nail at the ends. This blank is set to the width of the purlin, and the resulting angle is fixed with pieces of board.

A second template is used to mark the mounting cuts at the top and bottom of the rafters. Its base is plywood. When assembling the legs, you need to strictly follow the template so that you do not have to redo the structure. The upper part of the rafters is connected by a wooden or metal plate.

If the assembled roof trusses have significant weight, you will have to use equipment or devices for lifting.

The first pair of rafters is installed on opposite gables. It is fixed with temporary struts and leveled. A cord is stretched between the legs as a guide for installing the remaining trusses. The structure is connected by crossbars, struts and supports.

With a short span, the rafters are not fastened with a ridge girder. A roof with a width of more than five meters requires reinforcement of the structure with a ridge beam. This beam is attached both under the rafters and above them. The connection occurs with a gash and plates. For long rafters, support posts are installed to prevent sagging.

The completion of the installation of the rafter system will be the fastening of the sheathing.

To know how to properly perform a truss structure, you can watch a video describing the stages of work.

Video