Methods of attaching rafters to the mauerlat: basic methods and schemes for attaching rafter legs. How to saw the rafters of a gable roof? Carved rafters

The service life of a house directly depends on how well all parts of its structure are made. And the roof is no exception here, because it is it that protects the floors from precipitation and sun rays. In addition, the roof allows excess moisture to be removed from the walls of the building. If you decide to make rafters with your own hands, you need to familiarize yourself with the features of their construction.

Today there are many types of roofs. Despite the diversity design features, all of them are attached to the frame of the house using rafters - wooden beams that can be installed either straight or at a certain angle to the walls. Subsequently, they are mounted on the beams wooden elements, on which, in turn, the roof is laid. Before making rafters, you need to familiarize yourself with the main design features different types roofs

Types of roofs and features of their construction

The easiest to set up with my own hands are single-pitch or gable roofs. They are the ones most often used in construction country houses. At the same time, shed structures are mainly erected when arranging outbuildings: sheds, temporary buildings and other utility rooms. In the construction of residential buildings, sloping or gable roofs are used.

There are also the following types of roof structures:

hip;
hipped (hipped);
crusades.

These types of roofs consist of complex structural elements, so if it is necessary to manufacture them, it is better to seek help from specialists.

If we talk about rafters, they are also divided into two types and can be layered or hanging. The support for hanging rafters is usually provided by external or interior walls building. The upper end of the beams is attached to the ridge girder. The lower parts of the beams rest against the outer supports, which are the walls of the house.

When installing hanging rafters, you must remember that this type of structure does not have an internal support point. Improper installation can result in the pressure of the roof elements on each other becoming too high, which can cause the walls to topple or collapse.

To prevent this from happening, all elements of such a structure must be firmly connected to each other. To do this at the bottom rafter system a tightening belt is installed to prevent expansion of the construction truss. The hanging truss structure can be assembled both on the house and on the ground. In the second case, in order to raise the roof of the building, you will need to use a truck crane.

Unlike hanging structure, layered rafters are attached not only to the ridge girder, but also to the internal support, which makes the process of constructing this system quite simple and does not require the use of special mechanisms and equipment.

Materials required for arranging the truss structure

Before making rafters for two pitched roof, you should decide what materials will be used for their manufacture.

Here you also need to focus on recommendations experienced builders. For example, many craftsmen do not recommend using logs for beams, due to their heavy weight. In addition, it is advisable to use self-tapping screws rather than nails as fastening materials. In both cases, the use of overlays and liners will be required.

The amount of materials that are needed to make rafters for the roof also depends on the option of assembling the rafter structure. Today there are several of them:

using racks;
using struts;
using both racks and struts.

Taking into account all the above factors, the following materials and tools will be required to arrange the structure:

wood boards or beams coniferous species thickness from 40 to 100 mm;
timber with a section of 10x10 cm for the roof ridge and the manufacture of planks and mauerlat;
steel strip clamps;
nails or screws;
staples;
axe;
inclinometer or laser level;
hammer or screwdriver.

Before carrying out work, you will need to calculate the difference between the walls of the building for the roof slope. This can be done using a formula with the following indicators:

In this case, W is the distance between the walls of the house, L is the angle of inclination of the roof, H is the difference between the walls.

Determining the cross-section of timber or boards for arranging the rafter system

Or the boards that will be used for the manufacture of elements of the rafter structure depends entirely on their length. So, with a rafter height of 3 m, material with a cross-section from 8x14 cm to 10x12 cm can be used. An element height of 4 m will require the use of boards or beams with a cross-section from 8x18 cm to 10x10 cm. Beams or boards with the largest cross-section 8x22 cm or 10x20 cm should be used when the length of the roof rafters is at least 5 m.

Carrying out work on the arrangement of the rafter system

In order to make the rafters correctly, you first need to install the Mauerlat. This term refers to a roofing element usually made from logs or timber. It is in the Mauerlat that every detail of the rafter structure is installed. Thanks to this element, the load from the weight of the rafters is distributed over the entire area of the house. The number of Mauerlats depends entirely on the number of pairs of rafters, since the lower end of each rafter element is fixed in a groove cut in the Mauerlat.

Mauerlats are installed on the walls of a building under construction. At the same time, on both sides, its extension beyond the walls of the house should be from 40 to 60 cm. The extensions should have same value along the entire length. Several methods can be used to install the Mauerlat: fixing with staples, winding with wire, fastening with long nails, etc.

In the places where the rafter elements are attached to the Mauerlat, we make grooves that must completely correspond to the tenon at the end of each rafter. The grooves should be located at the same distance, at least 6-8 cm from the end of the beam or log.

When the required number of Mauerlats of the same length are installed on the walls of the house, you can start installing the rafter system. The structure is made taking into account the step between the rafters of no more than 2 m. If the thickness of the timber or board is minimal (about 40 mm), the step can be made smaller.

In order for the roof rafters to be folded at the desired angle, a template is made from boards based on calculations using the formula presented above. Using this template, all the necessary distances are measured and a tenon corresponding to the groove in the Mauerlat is cut out. Based on the prepared template, spikes are made at the bottom of all rafter elements.

At the upper end of the elements, grooves are cut at a certain angle for attaching the ridge girder. The size of the angle depends on the angle of the roof and the size of the ridge beam. The ridge can be mounted above the center of the rafters or, conversely, under them. The use of a ridge increases the rigidity of the rafter structure.

It is possible to fasten rafters without a ridge purlin: this method is usually used in the construction of small buildings whose roof span is less than 4.5 m. In this case, the upper ends of the elements of the rafter system are cut at a certain angle so that each pair has a groove and a tenon, which will be securely fastened to each other.

The prepared rafters are raised to the base of the roof and mounted in grooves on the mauerlats. Each post can be secured either with staples or long nails. In the case when a ridge girder is used, it is advisable to install additional posts under the rafters, which will eliminate the possibility of them sagging. The posts are installed from a board, the cross-section of which is smaller than the cross-section of the rafters, and are fixed to the mauerlat.

When the roof rafters are installed, it is necessary to prepare the sheathing to secure the roof. The type of lathing depends entirely on what kind of roofing will be laid on the roof elements. For example, lathing with a pitch of 10 to 50 cm is suitable for fastening metal tiles, slate and sheet roofing materials. Lathing, the distance between the elements of which will be no more than 1 cm, will be required for rolled materials, slate sheets or soft roofing.

If necessary, do truss structure You can use the above recommendations with your own hands. If the work is done carefully and accurately, the roof of the house will be reliable and will last for a long time.

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.

DIY rafter system

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. Used in the construction of 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, giving greater 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.

Options for roofs with hanging and layered rafters

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

Installation of roof struts

Hanging rafter technology

Technology for making hip diagonal rafters

Since the rafters for a hip roof are installed 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.
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.

Pulling boards ( Hip rafters) using 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 roofing material, for example, corrugated sheeting, and lay it correctly.

When building a rafter system, it is important to monitor every detail to ensure the reliability of the structure. Special attention pay attention to the attachment point of the rafters to the Mauerlat. It is in this place that the main part of the load is transferred to the load-bearing walls. In this case, it is important not only how to fasten what to use, but also the accuracy of the cut. After all, if the board is not fully supported, then it can break and lead to the collapse of the roof. In this article we will look at how to cut rafters and what methods exist for this.

Types of fastening rafters

Depending on the constructive solution, the presence of internal walls and the calculated load, various types of fastening are used. Each of them implies its own option for preparing rafters for joining with the Mauerlat. The three main mounting methods are listed below:

hard;
layered;
sliding.

We will not consider the last option, since when using it there will be no need to make cuts. It is usually used when installing roofs on houses made of timber. It is most suitable, since wooden walls shrink over time. Because of this, the rafter system may change geometry and leaks will appear.

In other options, you will have to make precise cuts. You will need precision measuring instruments, a construction pencil and an electric or chainsaw.

The strength of the roof depends not only on how correctly the cuts were made. Consider the following tips:

Select for rafters quality materials, because even if you make precise cuts, the block may not withstand the load. You can’t save money here, as this part takes all the load on itself.
The mounting points with the Mauerlat must be free of wood defects, such as knots. Although they are stronger than wood, turbulences form around them, which break at the slightest load.
When installing a roof, do not hesitate to ask for help, as this is a dangerous and responsible task.

A well-executed junction of the rafter leg and the Mauerlat guarantees long term construction services.

Cutting out a seat

It is important to understand that making the perfect cut on construction site impossible. The reasons may be different: lack of high-precision tools, uneven position of the Mauerlat, inconvenient position, and so on. Therefore, relative to the design value, the angle of inclination of the slope may change. The main thing here is to maintain a single line of rafter position.

The easiest way to make the same cut on the rafters is to use a template. True, this option is not suitable in all cases, as roofs are often uneven. Then you will have to calculate the angle and location of the cutting on each rafter individually.

For the base of the template, take a piece of board, a piece of fiberboard or plywood, even thick cardboard will do. On the workpiece, draw a line from the bottom edge at a distance of no more than a third of the width of the rafter. The same line must be drawn on all the beams that you plan to trim. The fact is that cutting deeper is not recommended due to loss of strength. Next, mark the points at which the rafters will be adjacent to the mauerlat, make a perpendicular line relative to the previous line.

Now let's move on to making the template, determining the angles of the vertical and horizontal parts of the notch. To do this, attach the workpiece to the end of the Mauerlat, maintaining the slope of the future roof. Opposite the corner there should be a point of intersection of the lines that were made before. Draw the lines of the triangle and cut out the resulting template.

Before transferring the markings to the rafters, check the accuracy finished product. Walk along the roof and check the degree of connection along the entire length of the Mauerlat. Make adjustments if necessary, but don't wait ideal option. Differences of 2-3 millimeters are acceptable.

Maximum concentration is important so as not to go beyond the outlined boundaries. If you are not sure about own strength, then use hand tools. This way you will reduce the percentage of defects and the time for rework.

The second cut is made with an ax, since the power saw can be stuck. This also requires skill and strength. It is important to make sure that the ax is quite sharp, then the job will work better and you can avoid chipping.

Finally, check the resulting cut against the template and make adjustments if necessary. After which you can install the finished rafter leg or make seats on the remaining parts.

Trimming for direct joint with Mauerlat

A simpler option is to make a butt connection. To do this, you need to determine the location of the cut and its angle of inclination. For this purpose, two options can be used: theoretical and practical.

For the theoretical method, you need to have a good understanding of geometry and calculate the desired angle on paper. Divide the distance from the ridge to the eaves by the length of the rafter. So, you will get the cosine of the required angle. In order to transfer it to the workpiece, you can use either miter saw, or a special square.

If you don't have a special tool at hand, make a simple template. Take a durable material, such as chipboard. On the sheet, mark 500 mm along the bottom edge, then determine the tangent of the required angle and multiply by the measured length. Okay, you get the other side. right triangle. By marking all the boundaries and cutting out the workpiece, get the desired angle. The sawed-off parts can be assembled immediately or you can wait until the entire set is completed.

In practice, you can easily mark a separate rafter by attaching it to the design position. To do this, position the beam so that its lower part is flush with the Mauerlat. Draw a horizontal line from the corner to the bottom of the rafter; it should be strictly parallel to the wall. Now you can safely saw off with any available tool and install the part. The remaining part will serve as a template for the remaining rafters only if the base is level.

Knowledge of geometry helps not only in determining the angle of the rafter leg, but also in determining the height of the roof, the length of individual elements, and so on.

Rafter frame sets the geometric and operational parameters of a pitched roof. Due to violations in installation technology, due to flaws in the manufacture of its elements, system distortions, traditional leaks, and holes in the coating appear, threatening emergency situations. In order to build a reliable and stable roofing structure, you need to clearly know how to cut and install rafters with subsequent fixation to the supporting elements.

Classification rafter legs

Rafters, or rafter legs, are called wooden or metal beams, installed on the frame of the house at a given angle. They define the configuration roofing structure, take on and firmly resist the sum of permanent and temporary loads acting on the upper enclosing system of the building.

The structural simplicity of the rafter legs is extremely deceptive. In fact, these are quite complex elements that require careful marking and careful cutting. Inconsistencies in the connections of the rafter legs with the Mauerlat, with each other and with other components of the system lead to a change in the shape of the slopes, disruption of the integrity of the coating and destruction of the nodes.

On the other hand, proper installation of rafter legs can correct some errors in the construction of the frame of the house, and not aggravate the situation by clearly repeating and increasing differences in wall heights. True, in such situations, the frame elements are manufactured individually and scrupulously adjusted after the fact directly on site.

However, before understanding the specifics of installation, you need to find out what their design differences are, according to which rafter legs are divided into two groups:

Hanging. A type of rafters that do not have an upper support. At the top of the roof, the rafter legs rest against each other with their ends. So that under the weight of the components roofing pie and snow, this design did not burst the mauerlat beam; the hanging rafters were connected with a horizontally installed tie.
Layered. A type of rafter legs, laid on two supports of different heights. At the top, they most often rest on a ridge purlin installed in a cross to the rafters; less often, their ends, sawn at an angle, rest against each other. The bottom rests on the mauerlat beam or rests against it.

The scope of their application and installation technology depend on which group the rafter legs belong to. The hanging variety is assembled on the ground, and the trusses, made in the form of peculiar triangles, are lifted to the roof and mounted in a form fully prepared for installation.

The advantage of constructing a rafter frame using hanging technology is the safety of work and the ability to make node connections as accurately as possible. If the simplest version of a hanging truss with a tie at the bottom is used in the construction of the roof, you can abandon the installation of a Mauerlat, in the place of which a narrow leveling board is quite suitable.

The disadvantages of hanging technology accompany the advantages. For example, a truss assembled on the ground is much more difficult to transport to the installation site than boards and timber for layered rafters. There are restrictions on the spans to be covered: the limit is considered to be 14 m, above which it is unreasonable to install wooden beams that are prone to sagging without intermediate supports.

The rafter legs of the layered group, both top and bottom, rest on independent structures. Their tops are laid on a purlin structure, which is mounted on floor beams or on a beam that replaces the mauerlat on the inner wall. The bottom is either installed on the Mauerlat or rests against it, catching on the beam with a tooth or a support bar sewn in place of the tooth.

The advantage of layered systems is rightfully recognized as the ability to cover spans of almost any size. It’s just that as the overlapped space increases, the design becomes more complicated: it is supplemented with struts paired with racks, additional purlins coupled with beds, and contractions.

The layered structure takes longer to assemble and install, because it is constructed not from trusses, but from individual elements. However, this particular scheme has more opportunities for correcting defects in the frame or unevenly settled frame. Because Layered rafters are laid individually; it is possible to slightly change the position and size of the unit in order to ultimately form an impeccably leveled plane of the slope.

Specifics of manufacturing and laying rafters

It is clear that for the construction of the rafter system, lumber will be needed - long-length products from forest processing enterprises with clear geometric parameters. You will need a board or timber, which, naturally, does not have mounting cuts or notches for installation.

Why are cuts and cuts needed? The fact is that when placed on an edge, the boards and beams have too small a support area. They only contact the Mauerlat with one vestma thin line, because of which, at the slightest load from above, they can simply “move out” from their occupied position and drag the entire structure along with them.

In order to increase the support area at the junction of the rafters and the mauerlat, or it and an additional purlin, a corner notch is selected in the beam or board, a tooth is cut out, or a support bar is sewn on. If the top of the rafter is connected to a mirror-opposite analogue, then for a reliable stop you will need a cut, the plane of which must be clearly perpendicular to the horizon.

The basic rule in the construction of rafter frames is that the platforms chosen for support in the lumber are strictly horizontal and vertical. At the slightest violation of horizontality and verticality, stability is lost, structural parts shift under their own weight and the action of the load until the complete destruction of the system.

Let us note that the nodes of rafter systems are responsible for ensuring the possibility of slight displacement and rotation when the load is exceeded. These movements are necessary so that the structure bends slightly, moves slightly, but does not collapse and remains stable.

These subtleties should be known to both the craftsman who has decided to make and install rafters with his own hands, and the owner of a house under construction who does not want to pay for the poor-quality labor efforts of the construction team. Let's look at common options to understand the essence of the process.

Construction of a roof frame using hanging technology

Let's look at an example of constructing a rafter system over log house baths The span between the walls is small, it is easier and more reasonable to cover it with a hanging structure, the installation of which will be carried out on the bypasses of the ceiling beams - matits.

A log base is an almost ideal option for installing hanging systems, because it is easiest to cut it into the horizon, eliminating the need to adjust the rafters in case of violation of the foot geometry. There is no need to install a Mauerlat. However, the tie will have to be moved upward to bypass the upper crown of the frame and form a useful attic space.

Before installing the rafters, stage-by-stage preparation of the log house is carried out. On both sides of the foot, we align the bypasses according to the lace tied to the nails driven into the two outer beams. On top of the bypasses we cut off the slab so that the edge of each beam ends with a flat horizontal platform.

The layer formed after cutting off the upper convexity of the log along the edges of the beams is leveled to the horizon according to the level. We apply the specified control tool to three or more beams at the same time. If the level is not long enough to carry out such a check, use a long strip or board instead.

After trimming off all the excess, we mark the sockets for the rafter teeth. To do this, we again use nails and lace. Note that nest sampling sites can be marked on the crossings both before and after the construction of hanging trusses. However, it is much more convenient to make the nests before making the rafters. They will help you carry out fittings with higher accuracy.

To make your work easier, it is advisable to find the center of the log house on the side of the future tongs. At these points it is recommended to nail along a control strip, one of the edges of which will indicate the axis of symmetry. You can do without slats if you already have some experience in building roofs.

We sew two inch boards 10 - 15 cm longer than the designed length of the rafters at the top with a nail or bolt so that they can rotate around this connecting point.
On a strip installed in the center of the future gable, we mark the design height of the rafter system. We put another mark above it - this is the height of the tooth, more precisely, the length of the vertical line laid from the base of the tooth to its top.
We place the boards sewn at one point at the extreme bypasses so that the corner of each board rests on the future socket under the tooth.
We align the connection point of the boards with the top mark on the rail, which determines the length of the rafters with the tooth.
From the bottom corner of both rafters we set off the height of the tooth, return with the template blank to the ground and cut out the tooth according to the markings.
We return the template blank to its place, install it by inserting the teeth into the slots intended for them. It may happen that after installation the top of the workpiece does not coincide with the instructions of the staff. Then you need to pull out the nail and adjust the position of the top, making sure to mark a new point.
After adjusting the top, we draw a vertical line of their upcoming joint on both boards, measure the size of the crossbar and mark on the scraps of the board the shape of the overlays for the upper junction of the rafters.

If everything turned out exactly and no further adjustments are required, the template is ready. We return with him to earth. We disassemble the workpiece and make cuts along the marked lines. The parts obtained as a result of fitting and fitting will serve as a standard for the almost continuous production of roof trusses in the required quantities.

We will assemble hanging trusses on the ground. Their installation, as well as fitting, should be carried out by at least two people. One master simply cannot cope with similar work. The person at the top will install the truss, and the second will change its position according to the instructions of the plumb line. The position of each leveled and installed truss should be fixed with temporary spacers.

To increase the stability of the system, we will install racks under the rafters:

Let's mark the mats for the installation site of additional supports using the already proven method: we hammer in a nail on opposite sides and pull the string tight.
We will hollow out nests in the logs according to the markings.
Let's try on a piece of timber for the installation site. Let's mark a line on it, taking into account the height of the tenon.
Let's make a stand and two pads for attaching it to the rafter.
We will install the support we have made and similarly secure the position of the truss on the other side. We continue to work according to the verified scheme until we equip each rafter with additional support.

To ensure rigidity hanging system trusses are connected by wind ties - boards, poles or slats nailed from the inside of the structure. WITH outside The rigidity of the rafter frame will increase due to the construction of the sheathing.

The rafter legs are attached to the mats with 200 mm nails or corner brackets. In this plan metal corners and plates with perforations for fasteners are noticeably inferior traditional methods. To the sides of the rafters we nail fillets made of boards, the width of which is half the size of the material used in the manufacture of the rafters.

The length of the fillies should be 70–80 cm greater than the designed width of the overhang. This distance is needed to securely connect them to the rafter legs. The fillies can be cut in advance, or you can nail scraps of narrow boards to the rafters without preliminary cuts, and then draw a line for the cornice. However, the first option is more convenient and economical.

In most cases, as in the example given, the fillies must be partially buried in the bypasses of the mats, for this:

We note the actual width of the filly at the bypass.
We make two cuts with a saw according to the markings for 2/3 of the thickness of the filly. We also use a saw to cut the log between the outer cuts. We refine the recess with a chisel accompanied by a hammer.
We install the fillies in the formed recesses and sew them to the rafters with nails 100 mm long.

Upon completion of the installation of all fillies, we hammer a nail into the outermost ones. Pull the control cord and mark where the excess should be sawed off.

Installation of a layered roof frame

The construction of a rafter frame using layered technology has much in common with the installation of a hanging structure. The fitting is carried out in almost the same sequence, so it makes no sense to describe the actions twice. The main difference is in the methods of forming the upper node, because the tops of the layered rafters have a support - a ridge girder.

If the layered rafters at the top simply rest on the ridge girder, they are laid either with a run, i.e. parallel to each other, or with a strictly vertical joint, similar to the joining of hanging legs. However, in most cases, they try to secure the upper part with a notch or a vertical cut, tightly abutting it to the ridge beam.

There are schemes according to which the layered rafters rest not on the ridge, but on the side girder. In such situations, the top is formed according to the hanging principle, and the point of support on the purlin is formed with a corner notch.

Let us analyze the most popular option in private construction for constructing rafter legs based on the lower corner notch and on the ridge run through a vertical cut. Please note that the maximum cutting depth should not exceed 1/3 of the board width.

Option for marking with a construction square:

On the square we mark the height of the roof and half the span on a scale. These values display the slope of the slopes and set the main angles. The proportions must be kept exactly.
If further use of the square is not planned, then you can mark the deferred points with screwed bosses or short screws with screws; if you plan, then better paint, which can be removed with a solvent.
We apply a square to the laid flat board with the side on which the height of the roof is marked. We draw a line according to the readings of the square - this is the line of the upper cut of the rafter - the section of its interface with ridge run.
Cut along the marked line with a circular saw. We lay the board for sawing flat, as it should be when cutting wide. Longitudinal cuts are made on the edge.
From the top of the formed angle we set off the length of the so-called diagonal. This is the distance from the point of connection with the purlin to the outer edge of the Mauerlat or top harness, if a frame house is being built.
Move the square to this point. We draw a line parallel to the first one.
We turn the square over, move it along the workpiece so that 2/3 of the total distance is on the left, and 1/3 on the right. In the picture these are 8ʺ and 4ʺ.
The line of the smaller segment will mark the cut for us.

At the end, we draw the outline of the eaves overhang on the board, cut it along the outlined lines and use the rafter blank we made ourselves to cut the remaining elements of the roof.

You can apply the described method without a construction square and marking the roof parameters on it. It is enough to imagine the process to set aside the necessary distances with a conventional drawing tool. However, without experience, you can get confused in calculating angles and segments.

To help beginning builders, a template has been developed with options for forming corner notches. It will help you navigate the production of rafter legs from the most common lumber in this area.

In cases of laying rafter legs with notches in the upper and lower parts, it should be remembered that the depth of both notches must be the same so that the roof slope does not change during construction work. Usually, to create two equal notches, an auxiliary block is used, the thickness of which is no more than 1/3 of the thickness of the board.

The rafter blank is then installed edge-on on the mauerlat and on the purlin. The block is applied to the side in the area of the lower and upper node to outline the notch.

If a notch is needed only in the lower part of the rafter, and the top will rest on the purlin with a cut, the board is installed below on the mauerlat, and at the top on the purlin and block, so that as a result of cutting the angle of the slope does not change. At the bottom, a second block of a similar size is applied to the future node and, with its help, the outline of the future notch is outlined.

The same methods are used to form cuts with teeth. The only difference is in the shape.

The installation of layered rafters begins with the installation of two outer trusses. The elements are mounted one at a time, their position is carefully checked using a plumb level. Most often, the outer trusses are made from paired boards, because more load is distributed over them. They are fixed with temporary spacers, then connected with lace or strip to indicate the plane of the slope.

Ordinary rafters located between the outermost load-bearing trusses are installed according to the instructions with laces. If necessary, adjust the position of the legs according to the actual situation.

Video about installing rafter legs

Installation of rafters with fastening with metal corners:

How to make rafter legs with notches for mounting on the Mauerlat:

Construction of a rafter frame for a garage roof:

We have cited and described only part of the methods for constructing rafter frames. In reality, there are significantly more manufacturing and installation methods. However, analysis of the basic options allows you to perfectly understand how to properly make rafters and roof trusses, and how to saw them before installation.

KakPostroit.by 21.02.2017

The rafter system of a gable roof is a simple design that can be installed with your own hands even by a novice developer. You just need to make preliminary calculations, familiarize yourself with the details and stages of roof construction, and calculate the materials needed for installation. When making calculations, it should be taken into account that load bearing capacity a gable roof depends on the influence of loads on it from wind, snow, and the weight of materials.

To make the process of building a gable roof truss system as easy as possible for you, detailed information is presented below. step-by-step instruction for installing a rafter system with your own hands.

Requirements for building materials

For the installation of a rafter system the best option There will be the use of lumber from coniferous wood - pine, spruce or larch, grades I - III.

The material for the rafters is taken at least grade II, the mauerlat is made from boards or timber of grade II, material of grade II is taken for racks and purlins, the sheathing is made from lumber of grades II-III, it depends on the roof. Crossbars and tie-downs are made of Grade I material. Grade III material can be used on linings and linings.

Note! The lumber must be dry with a moisture content of no more than 20%. Before installation, it should be treated with fire retardants and antiseptics against fungal diseases.

Lumber should be stored under a canopy, providing protection from the sun and moisture. Level the storage area and cover the lumber with pads for ventilation.

For installation you will need fastening elements: ties, plates, studs, bolts with washers and nuts, self-tapping screws with EPDM gaskets, 2.8 mm thick, mounting tape, galvanized brackets.

Brackets are used when attaching the Mauerlat; they are secured with nails or self-tapping screws.

KR corners serve to attach the rafters to the mauerlat and prevent the rafters from moving.

All fastening material must be made of high quality material and be protected against corrosion.

Tools for constructing a rafter system

To install a gable roof rafter system, you will need the following set of tools:

tape measures of different lengths 5, 10, 20 meters;
markers, pencils;
cord for tensioning;
hammers, for various purposes, nail puller;
scissors, for cutting;
roofing knife;
putty knife;
scotch;
hacksaws, electric saw, electric drill with various drills and attachments;
screwdriver with attachments;
markings, horizontal and vertical levels;
slats, rulers;
polyurethane foam;
safety belt and rope - for safe work.

Keep all tools on the roof in a tool bag for safety reasons.

Types of rafter systems for a gable roof

Sent rafters

They rest on the mauerlat and racks installed on the internal wall, with a pitch equal to the rafters. To provide rigidity for spans of 6 m, additional struts are installed.

Scheme of layered rafters of a gable roof

Hanging rafters

If the building is small in width, you can arrange a rafter system where the rafters rest on the mauerlat or walls, without intermediate supports. The maximum span is 9 meters. Such roofs can sometimes be installed without a Mauerlat. The rafters are installed on the wall using spacers; in this embodiment, a bending moment acts on the rafters.

To unload, wooden or metal plates are installed. They securely strengthen the corner. For hanging rafters longer span The headstock and struts are installed. For hanging systems, the rafters are made with a larger cross-section, and lumber is chosen at least grade I II.

Scheme of hanging rafters of a gable roof

Calculation of the rafter system

You can determine the cross-section of a gable roof beam required in a rafter system by collecting all the loads acting on it: the weight of the covering, sheathing, snow, wind pressure, precipitation.

Constant loads can be determined by the weight of 1 m2 of roofing and sheathing. It is important that the weight per 1 m2 of roofing be in the range of 40-45 kg.

Variable loads from snow and wind are calculated using table values SNiP regulatory documents, depending on the height of the building and temperature zone. The load from snow is equal to its weight multiplied by a coefficient depending on the slope of the slope. All these calculations are performed during the project.

What if there is no project and the roof is being erected on a small building? You need to look at the construction of a house in the neighborhood, which is being carried out according to a design whose roof area is the same as your building. The gable roof rafter system will serve as a model.

Dimensions of timber for rafters

At the top point a ridge is laid that connects the rafters. The height of the ridge depends on the slope of the roof. The slope is affected by the choice of coating material. The minimum sizes are:

for tiled roofs, slate 22 gr.;
for metal tiles - 14 g;
ondulin - 6 g;
corrugated sheeting - 12 gr.

The optimal angle is 35-45 degrees. tilt, ensures rapid discharge of water and snow. In regions with strong winds, the roofs are made flat and then the angle of inclination is within 20-45 degrees.

The height can be determined using the formula: H=1/2Lpr*tgA. Where A is the angle of inclination, L is the width of the building.

The task is simplified when using a ready-made table. The coefficient depends on the width of the building and the angle of inclination. Multiply the coefficient by 1⁄2 the width of the building.

The rafters are made from pine or spruce bars, with a section of 50x100 mm, 50x150 mm.

The size of the rafters depends on the pitch. The pitch of the rafters is smaller, a larger number is installed, and the cross-section will decrease. The distance between the rafters on a gable roof ranges from 600 mm to 1800 mm, it all depends on the design of the roof and the materials used for its construction.

The roof does not end at the level of the walls; it is extended outward by 500 mm. The rafter leg can protrude, or a board or block can be built up. In this case, moisture does not get on the wall and the foundation is not poured.

Step-by-step installation of a gable roof truss system

The rafter system of a gable roof consists of the following elements:

Mauerlat.
Lay down.
Racks.
Rafters.
Struts.
Puffs.
Lathing.

Mauerlat installation

Fastening the Mauerlat to a monolithic reinforced concrete belt

Mauerlat evenly distributes the load on the walls of the building; its installation can be done in several ways:

attached to the wall through a reinforced concrete belt with studs;
studs are inserted into the masonry;
simple and common way to simple roofs, fastening with wire rod.

For it, take timber with a cross section of 100×100 mm, 150×150 mm or 200×200 mm. Which section to choose depends on the size of the roof and its covering. The Mauerlat is joined along its length; to do this, make 100 mm cuts, 500 mm long, fold the bars and fasten them with pins.

In the corners, the mauerlat is tied with notches into the floor of the timber, fastened with staples or bolts. For wooden buildings, the Mauerlat is the last crown. On brick walls, make a monolithic reinforced concrete belt with a cross-section of 400×300 mm. Along the belt, place threaded pins 12 mm in diameter, every 120 mm, for fastening.

Drill holes with a diameter of 12 mm in the Mauerlat, lay them so that the pins go into the holes. Tighten the top with nuts. First, we lay two layers of roofing felt or roofing felt under the block. On the outside of the wall, lay the mauerlat with bricks. Lay the Mauerlat on a horizontally and vertically level base. You need to check with a level that the surface is horizontal. Check diagonals. If necessary, level with pads.

Installation instructions for beds, racks, rafters, struts and tie rods

The installation of a gable roof rafter system with your own hands is carried out in the following order:

Install the beam with the rafters in place.
Mark the installation step of the rafter legs.
Prepare according to the size of the rack.
Install them if there is a need to secure them with spacers.
Lay the purlin. Check geometry. Install fasteners.
Try on the first rafter leg and mark the cutting areas.
Mark the points and install the rafters at the beginning and end of the roof, stretch the cord between them in order to align the remaining elements along it.
Having installed the rafter leg, we first attach it to the mauerlat, then to the ridge purlin, to each other.
Screw each second leg to the mauerlat with wire.

The rafters are fastened to the mauerlat using notches, stop corners and a hemmed support bar. Secure with nails or staples.

Methods for attaching rafters to the Mauerlat

Install the support posts on the beds or pads and overlays. A log is a beam 50×100 mm or 50×150 mm, laid on the middle wall along a layer of roofing felt. Place brick pillars under the linings, 2 bricks high.

The rafter legs are connected to each other at the ridge. Let's consider the common connection nodes of the rafter system:

They make cuts at one leg and cut down at the other. Insert one leg into the cut of the other and fasten with a bolt.
Install overlays, wooden or metal.
Using notches in the purlin, they are secured with nails or bolts.

Methods for connecting rafters on a ridge

To ensure the roof's resistance to wind loads, tie-rods, struts and purlins are installed. The tightening is a 100×150 mm block, purlins and struts are made from a 50×150 mm or 100×150 mm block.

With the installation of contractions, the reliability of the rafter structure increases. The sections of the timber are the same as the rafters. They are attached to the legs with bolts or nails. The device of struts adds rigidity to the structure. They are installed tightly to the surface of the rafters

Lumber has standard length 6 m. Rafters can be longer. Then you need to dock them. There are several connection methods:

Fasten by placing bars on both sides at the junction, connecting them with nails in a checkerboard pattern.
Connect with an overlap, one part of the rafters to another, at a distance of 1 meter, fasten with nails in an alternating order.
Make a cut obliquely, cut out part of the rafter legs, connect them, strengthening them with bolts.

Sheathing device

Lathing is installed along the roof rafters. It serves to distribute the load from roofing material and snow onto the rafters. Acting air gap between the roof and the rafter system.

The design of the sheathing depends on the roofing material used:

under soft tiles make the sheathing continuous, lay an anti-condensation film on the rafters, press it on top with a counter batten, nail the sheathing onto it, then OSB boards and underlay carpet, lay tiles on top.
Under the roof made of corrugated sheets, the sheathing should be sparse. The pitch of the sheathing depends on the brand of corrugated sheeting, its thickness and the angle of inclination of the roof.
The lathing for standard slate should be made in increments of 500 mm from a bar of 75×75 mm or 50×50, as well as boards from 30×100 mm. The design features of the roof should be taken into account when making the final choice of the appropriate option.

The lumber from which the sheathing is made is first or second grade pine. It is advisable to take the width no more than 14 cm. With a wider width, the boards may warp and damage roofing decking. The length of the nails should be three times the thickness of the sheathing. Lay the boards along the ridge. Install the first board of greater thickness to the height of the roofing.

Install continuous sheathing along the roof slope.

The first layer is to place a board along the ridge from it at a distance of 500-1000 mm to the next one and so on. Lay the second layer of sheathing along the rafters. Place the joint between the boards only on the rafters at intervals. Sink the nail, head and all, into the flesh of the wood.

Cornice overhangs

They are installed to protect against precipitation and play an aesthetic role. Eaves overhangs are arranged tightly without gaps. The final stage of installing the roof.

Diagram of the eaves overhang of a gable roof

Gable

The gable roof has two gables. They have the shape of a triangle, with the apex at the ridge and the sides coincide with the slopes of the roof. Gables support rafters and enclose attic space. They protect from wind and precipitation and provide stability to the roof.

In wooden buildings, the pediment is framed. In brick buildings, frame or brick. Gables made of brick or gas block are erected before the roofing is installed. They require very precise execution.

Frame pediments fit into the finished opening when the rafter system is already assembled.

The frame is made of bars or boards. The frame elements are connected on tenons or in the wood floor, all fastened with nails. They are sheathed by nailing boards, lining or siding, maintaining the color scheme in the decoration of the building facade. To construct a window opening, an additional frame is made under it according to the size of the window. If the attic is insulated, then the gable also needs to be insulated. The insulation is placed in the middle of the frame. Mineral wool insulation with reduced flammability is used. From the outside, the frame is covered with a hydro-windproof film or windproof membrane, With inside a vapor-proof film or a vapor-proof membrane is nailed under the finishing material.

The appearance of the house and its service life directly depend on how the roof protects the ceiling, how well it drains water from the base and from the walls. In our article we will talk about how to make rafters for your home, taking into account all the tips experienced craftsmen and excluding the most common mistakes.

Although there are many types of roofs, individual suburban construction The most common types are two types: single-pitched and gable roofs.

A pitched roof has the simplest design, which even a person far from construction can master. But such roofs are mainly used in the construction of auxiliary and outbuildings.

For residential premises, gable or sloping (mansard) roofs are most often installed. Despite some design difficulties, it is quite possible to build such a roof yourself, if you listen to the advice of the experts and carry out everything step by step, slowly, according to the preliminary design plan.

Hip roofs have a very complex design and quite labor-intensive. The installation of such roofs should be trusted to professionals. However hip roofs– the most reliable, they will withstand even under particularly strong wind loads.

A hipped (hipped) roof is used for square buildings. In fact. It is a type of hip roof.

Of all the above roofs, the most complex is the cross roof. She has complex structural elements– valleys (valleys). Such diagonal auxiliary rafters must be installed additionally.

This is a very labor-intensive job that does not tolerate haste and carelessness. Snow usually accumulates in these places, and the quality of the roof and its reliability depend on how well this structural part is executed.

Each of the above types of roofs consists of two main elements: the roof and. The roof is the enclosing part of the roof structure, the rafters are its load-bearing part.

Main types of rafters

Before making rafters, you need to find out their design features and decide on the option for their arrangement.

In roofing construction, there are two types of rafters:

Hanging.
Layered

Hanging - inclined beams mounted on supports with different heights. The outer walls of the house often act as support ( pitched roof) or external and internal walls at the same time (gable roof).

It is not at all necessary to secure the rafter legs in the same plane of the roof opposite the slopes. They can be laid alternately on the ridge run.

This alternating connection of rafters in the ridge allows you to set up a construction truss. To do this, you need to tie all the elements of the hanging rafters together into a rigid single structure.

It is important to know: the truss must be installed on the outer two supports. Thus, due to the lack of internal support, the rafter legs will rest against each other at the ridge connection, creating quite a strong horizontal pressure. If the load distribution is incorrectly calculated, then the thrust, transmitted to the walls, can even topple them.

In order to eliminate such a mistake, experts advise making a tightening belt at the bottom of the truss. Its main mission is to extinguish the resulting thrust.

What types of rafter systems are preferable when building a country house?

There can be no clear answer to this question. It all depends on the design of the house, the expected load on the roof and the choice of roofing material. So, layered ones have a simple structure; complex devices and mechanisms are not needed for their assembly.

In contrast, hanging rafters can even be assembled on the ground, but will require additional equipment (such as a truck crane) to get them into place.

Hanging rafters can also be assembled from individual elements directly on the house. Further work depends on how to install the rafters correctly.

So, it is important to know: you need to make a boardwalk on attic floor. And in order to attach the parts temporarily, you will need auxiliary jointing and braces made from boards.

Materials for rafters and their connections

Rafters are made of beams or boards. For this, coniferous wood is usually used. The thickness of the board should be at least 40-60 mm.

And that's all wooden structures should not have any defects in the form of knots or cracks, well dried. Since logs are heavy, many roofers do not recommend using them.

But rafters made from boards are easy to install and light in weight. You can even work with such material yourself, without the help of specialists.

Important: to connect the racks of the rafter system with the beam or purlin, we recommend using notches.

There are three options for assembling the rafter system:

With stands
With braces.
With racks and struts at the same time.

Let's look at how to make rafters correctly. Depending on the size of the span between the external walls, you need to use:

use boards for posts and rafters;
timber 10x10 cm - for designing the ridge girder;
The mauerlat and the bench can be made from logs, cutting them into two edges, or from the same timber (10x10mm).

When designing a ridge assembly, it is important to nail special clamps made of steel strip to the girder and to the mauerlat using large nails.

You can do without steel clamps, but then you will have to use thick wire twists (with a diameter of 6 mm).

How to make the right rafters for a stone or brick house? On a brick or masonry lay a continuous mauerlat.

In order to securely fasten it, we recommend placing a piece of timber or log (about 50 cm) under each rafter leg. And then, using clamps, secure it to metal hooks; they must first be installed below the Mauerlat by 30 cm.

How to properly make rafters in paving or chopped wooden houses? IN wooden buildings The rafters are laid on the upper crown of the wall.

They are secured with clamps that are nailed to the second crown. A truss plank truss can be equipped with spans (6-8 cm) or using a crossbar.

We arrange the structural elements of the truss as follows:

Single tightening using boards, the thickness of which is the same as on the rafters.
For double tightening, you can use slightly thinner boards (more than 40 mm).
For linings and crossbars, use boards with a thickness of 30 mm.

Let's look at an equally important issue: how to properly assemble the rafters, ensuring the roof is rigid in different directions? If the truss has the necessary rigidity, then this is quite sufficient for the longitudinal direction.

But, in order for the roof to withstand wind loads, it is necessary to install a pair of diagonal connections in the transverse direction, and in each of its slopes.

A little advice: diagonal connections can be made using boards 30-40 mm thick. For layered rafters under the ridge and between two neighboring drains, we recommend installing braces. However, if you plan to make a diagonal (oblique) flooring along the sheathing, then you don’t have to do the braces.

Determine the required rafter section

Several factors on which the cross-section of the rafters depends:

From the expected load on them (from the weight of the future roof and snow cap).
Depending on the size of the span.
From the installation angle and rafter pitch (i.e. from the roof slope).

For middle zone In Russia, it is preferable to install a gable roof with a slope of 30 degrees or more, with a rafter pitch of at least 120 cm.

Let's consider the dependence of the rafter cross-section on the length of the rafter leg:

So, in increments of 300 cm, boards with a section of 8x14 can be used for rafters; 6x14; 4x18 cm or bars with a section of 10x12 cm.
For a pitch of 400 cm, you can use boards with a section of 8x18; 6x20 cm or bars with a section of 10x16 cm.
For a step of 500 cm, you can use boards with a section of 8x22 cm or beams with a section of 10x20 cm.
In those structures where struts were used, the height of the board or beam can be slightly reduced.

Now that you have learned how to assemble the rafters correctly, you can safely get to work. To make lifting and moving wooden structures more convenient, call a friend for help.

After the rafters are installed, you need to work on the roof. Try to plan and carry out such work as quickly as possible in order to protect the rafter system from possible getting wet. It is best to do this in sunny summer weather.

Choose roof covering necessary taking into account the slope of the roof and its steepness. It is quite clear that the choice of roof covering also depends on the material capabilities not only during the initial installation of the covering, but also during its subsequent operation.

It is important to consider: the steeper the angle of the roof, the more money will be required for its arrangement. This is due to increased consumption necessary materials. But, at the same time, steep roofs drain much better rainwater and snow, accordingly they perform their function 100%, therefore they will also last much longer without repair.

Despite the fact that currently the roofing materials market is pleased with its variety and huge selection. However, a universal roofing material has not yet been invented.

So that it is inexpensive, suitable for a wide variety of weather and climatic conditions, lightweight and durable.

IN Lately more and more more people trying to make roofs for own home with your own hands.

Of course, a roof can be made from many different materials the most popular of which are slate, metal profile, plaque. But all these materials have one thing in common: rafters must be used to make the roof.

On specific example I would like to show you exactly how to make a roof using rafters and how to cut the rafters.

In order to make a roof using rafters, you need to do the following work:

1) First you will need to do calculation work. In our case, the length is 4 meters and 80 centimeters, and the width is 2 meters and 40 centimeters. After this, a calculation is made of exactly what length the rafters will be

2) Then, using a protractor, the desired angle of inclination is determined

4) If you need to make a hipped roof, you can use the drawings below

5) Then take the width and divide by 2 - it turns out 1200 on both sides. After this, we measure from the opposite line the size of 2163 cm - this is exactly the one that will be after measuring the angle;

6) in mirror image we will need to draw the other wing of our roof;

7) After this, 2400 cm is measured in the center and a triangle is drawn. These will be the so-called roof slopes;

8) Now that we already know how long the rafters should be, we will need to make them and cut the rafters correctly.

How to cut rafters correctly:

— First you will need to take the boards in the quantity you need;
— The boards are stacked, with the ends facing down;
— Two suitable strips are placed along the edges and attached to the rafters;
— On the entire pack of rafters, you must mark the length that is suitable for the roof;
— Then the corner of the rafters is cut.

Cut corners of rafters. In order to do this you need to make a triangle, which you can make yourself.

You can see what this triangle looks like below

Then an aluminum strip of the same size as the corner itself is set. Then a triangle is installed on the side of the rafters and an angle is drawn strictly along the plank.

Using the Mauerlat you will need to saw down this corner.
After this, you just need to assemble the finished roof from the rafters.

You can also watch the video installation of the rafter system

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. The rafter frame is 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:

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 rafter system and the building structure into a common structure and distributes the load on the walls.
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.
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.
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.
Tie-downs are crossbars made of boards connecting the rafter leg.
Racks are bars installed vertically; they are installed to support the ridge girder.
Overhangs are parts of the rafters that protrude beyond the walls. They allow precipitation to be removed from the house.
Struts - serve to strengthen the rafters, allowing you to create durable structures.
Lathing - boards necessary for tying rafters and laying roofing material.
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, various types of fastening are used: 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. Wind coefficient and snow load must be included when calculating the 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, install support posts, protecting against 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.