Nodes of a wooden truss system. Truss system nodes - how to make a reliable roof? Rigid rafter attachment

The rafter system is the frame of the roof of the house, which carries and evenly distributes the weight of the roofing cake, sometimes reaching up to 500 kg / m2. The reliability of this kind of skeleton depends on three factors: the accuracy of the calculation, on the basis of which the number and section of the supporting elements are selected, the material from which it is made, and also on the correctness of the fastening technology. Knowing how to properly fasten the rafters, you can significantly increase the bearing capacity of the frame, making it more durable and reliable. Errors in installation, on the contrary, lead to tangible loss of strength and deformation of the roof. In this article, we will talk about the main types and methods of fasteners with which you can qualitatively install the rafters with your own hands.

The roof truss of a house is a system of interconnected supporting elements made of wood or metal, which give the structure its shape, slope, and also evenly distribute its weight between the load-bearing walls. Its main component is the rafter legs, which are beams installed at an angle, which are connected in pairs along the slope, forming a ridge at the top point of their connection. There are two main types of rafters:

Forced. Inclined rafters are called supporting elements, which in the roof structure have two points of support - on the ridge girder and the Mauerlat. A rafter system of this type is used in structures that have one or more load-bearing walls inside, on which the rafters can be "leaned". Such fastening of the rafters allows them to be relieved by using additional vertical supports.
Hanging. Hanging elements are called elements that have only one point of support, located where the rafters are attached to the wall or Mauerlat. The hanging-type rafter system experiences a load not only on bending, but also on expansion, therefore it is reinforced by horizontal compensating elements (crossbars, puffs, contractions).

Note! In most of the most popular rafter systems, the rafters are attached to the Mauerlat. Mauerlat is a massive beam or beam with a section of 150x150 mm or 200x200 mm, laid along the load-bearing walls of the structure, on which the rafter legs will subsequently rest. It relieves pressure on the walls of the house and also distributes the weight of the roofing cake evenly. You can attach the Mauerlat to the upper belt of the walls using anchor bolts or embedded metal studs.

Main connectors

The rafter frame is called a system because all of its elements are closely interconnected and fixed, as a result of which the roof structure acquires a stable shape, rigidity and high load-bearing capacity. Each connecting node between its parts is a vulnerable spot that can easily deform under load, so all fasteners must be performed strictly according to technology. Experienced craftsmen distinguish the types of joints in the roof structure:

Fastening the rafters to the ridge beam. This connecting node is typical only for layered rafter systems, in which the upper part of the rafter leg rests on the ridge girder, fixed on vertical racks. Attaching the rafters to it can be done using metal pads, nails or sliding slide mounts.
Fastening the rafters to the Mauerlat. The most important fastening point of the rafter frame is the junction of the Mauerlat bar with the rafter legs. You can fix the rafters on it with nails, metal corners or wooden bars.
The connection of the rafters to each other. To lengthen the rafter legs, if the length of the ramp exceeds the standard length of lumber, they are assembled from several elements connected to each other using nails, glue or metal pads.
The connection of the rafter legs with auxiliary supporting elements. In the structure of the rafter frame, the rafters can be connected with a tie, crossbar or struts to increase rigidity, strength and bearing capacity.

Please note that any cuts performed to attach the rafters to beams, mauerlat or other structural elements of the frame lead to a decrease in their strength, therefore experienced craftsmen recommend connecting them together using corners and overlays.

Fixation methods

When deciding how to attach the rafters to the Mauerlat or ridge girder, it is necessary to choose the right fastening accessories. The modern construction market has a huge assortment of fasteners of various designs and sizes. The main criteria for choosing fasteners are the material used for the manufacture of the rafters, their cross-section, as well as the type of load to which they are subjected. There are the following ways of attaching the rafters:

Experienced craftsmen believe that the most reliable way to fix the rafters is to use metal corners, which firmly connect the wooden elements to each other, rigidly fixing the angle between them. The corner overlapping the joint between the rafter leg and the ridge bar or Mauerlat serves as a kind of space between them.

Types of mounts

Wood is a natural material that, in the process of leveling out moisture and drying, shrinks significantly, due to which the linear dimensions of the structure change. That is why experienced craftsmen recommend erecting a roof for timber and log houses, a year after construction, when the shrinkage process passes from an active to a passive phase. If you fix the wooden frame elements rigidly, then after drying, the roof of the house may deform. Therefore, the following types of fasteners are used to connect the rafters:

Interestingly, there are several options for combinations of movable and fixed connecting nodes. The most common are rafter systems with one rigid and two sliding fasteners, which provide sufficient mobility with a high strength and rigidity of the structure.

Types of fasteners

Among experienced roofers, disputes do not subside, the more effective it is to fasten the rafters to the floor beams and the Mauerlat. However, in most cases the catch is that in these conditions it is more practical to use nails or screws. Both of these fasteners have their own advantages and disadvantages:

The good thing about nails is that to hammer them in, you only need a hammer, which is in every household. However, some masters complain that it takes too long to hammer them manually. It is worth recalling that special serrated nails are used to fix the rafters, which reliably adhere to the wood.
To assemble the rafter frame, use galvanized self-tapping screws that are not afraid of corrosion. Due to the thread, they are firmly screwed into the thickness of the wood, reliably fixing the elements to each other. Screwing them up quickly and conveniently with a portable screwdriver. The disadvantage of this type of fastener is that, when dismantling, it is long and dreary to remove the screws from the tree.

Most experienced roofers agree that for fixing the rafter legs it is better to use galvanized brushed nails, the length of which is 5-3 mm longer than the thickness of the lumber. Correctly selected fasteners are the key to high-quality and long-term fixation of the roof frame, which will not be afraid of either mechanical influences or wind load.

Video instruction

The attachment points of the rafters must provide the necessary strength of the roof frame. It is important to choose the right technology for assembling the elements of the rafter system among themselves and their attachment to the supporting contour, so that the finished roof is able to withstand the design loads.

Features of roofing structures

The task of layered and suspended roof truss systems is the most uniform transfer of the load of the truss structure, which, in turn, distributes the load on the load-bearing walls and the foundation of the building. The truss structure is usually a Mauerlat (a beam laid lengthwise on each load-bearing wall). It can also be floor supports (stacked across the wall) or the upper crown of a frame made of timber or logs.

The choice of the method of attaching the rafters to the Mauerlat depends on their type. The shear structure forces the Mauerlat to work in shear, while the hanging trusses work in compression, the direction of which coincides with the orientation of the load-bearing walls.

Setting the tightening

Installation of a gable roof requires the installation of a rafter system of a layered or hanging type. In order to mount a rigid suspended truss truss that does not transmit spacer loads to the walls, it is required to correctly perform the attachment points for horizontal lintels - puffs and crossbars.

Depending on which roof structure was chosen, the brace can be mounted at the base of the rafters and act as a floor beam. The rafter truss, which is attached to the Mauerlat, is equipped with a crossbar - a jumper located closer to the ridge to give rigidity. In mansard roofs, the crossbars are the basis for the ceiling sheathing.

When installing the tightening, it is recommended to connect the joint by the method of "cutting into the rafter with a semi-pan" using a fastening screw. This method of installation requires precise adjustment of the elements, since with large gaps, at the mating points, the attachment unit may collapse under load.

An easier way is overlapping installation. In this case, the jumper is made from a board or two boards installed on both sides of the rafter leg. Nails are used as fasteners. The assembly can also be a bolted connection, but this will reduce the load-bearing capacity of the rafters by 20%.

Another option is to install a crossbar. Installation of this type of assembly became possible after the invention of nail plates. The design is capable of withstanding high loads - reliability is ensured due to the tight abutment of parts and strong fixation on both sides due to the large number of teeth on the plate.

The cross-section of a bar or board for the manufacture of a spreader bar must coincide with the cross-section of the rafter.

Mauerlat: attachment points for rafter legs

The support of wooden rafters on the Mauerlat can be performed using two technologies:

rigid attachment to the Mauerlat;
sliding mount to the Mauerlat.

With a rigid attachment, any kind of displacement of the rafter leg, which rests on the Mauerlat (bends, shifts, torsion), is completely excluded. For this purpose, when installing the roof truss system, the installation of the rafters can be carried out using a hemming bar, which prevents the rafter leg from slipping at the point of support. Lateral shifts with this connection method are eliminated by the installation of metal corners.

In the second version of the rigid attachment of the rafter leg to the Mauerlat, it is necessary to gash (saddle) at the bottom of the rafter bar or board. The plane of support must be horizontal; for this, the saw in the rafters is made at an angle corresponding to the slope of the slope. To fix the knot on both sides, the rafters are driven at an angle along a nail (inside the Mauerlat they must be crossed), from above, a third nail is driven vertically through the rafter into the Mauerlat.

A sliding mount is usually used when erecting a rafter system on a house from a bar or log. In this case, the basis for supporting the rafter legs is not the Mauerlat, but the upper crown of the log house. To avoid deformation of the roof when the house shrinks, it is necessary to make a knot with a certain degree of freedom for the rafter leg. Often for this purpose, a special metal fastener is used - a sliding support ("slide"). Its upper part is a loop that moves along a guide fixed on the rafter leg when the geometry of the frame changes.

Other methods of mounting the sliding assembly are also used. A saw is performed in the rafter leg, the beam is set with a cut on the upper rim, after which it is fixed in one of the following ways:

by means of one vertically driven nail;
with the help of nails hammered from both sides, crossing in the Mauerlat;
by means of a staple;
by performing a single fixing with steel fixing plates.

This method of fastening allows the elements of the system to move relative to each other when the geometry of the building structures changes.

Ridge connections

The device of a roof rafter system with two slopes implies the presence of a horizontal rib in the upper part of the roof, formed as a result of the abutment of the slopes - the ridge. The ridge knot can be performed in several ways, the choice depends on the type of rafter system and the characteristics of the building itself.

The slab construction involves attaching the rafter legs to the ridge girder - a horizontal beam located on racks parallel to the long walls of the house. The upper ends of the rafter legs should be cut at an angle corresponding to the angle of inclination of the slopes. The abutments of the cut ends of the rafters to the ridge should be as tight as possible. Nails are used as fasteners. Inclined rafters are used if it is possible to install racks on the inner wall or columnar supports for attaching the ridge girder. In addition, the walls must be equipped with a Mauerlat to support the rafters.

Assembling a hanging type truss requires joining the upper ends of a pair of rafter legs. To do this, the end of each of the rafters is cut at an angle equal to the angle of inclination of the roof, the beams are connected by cut planes - it is required to ensure their tightness. They are fixed with two nails driven at an angle into the upper planes of the rafters. Then, on each side, a wooden lining or metal plate is nailed, which cover the joint.

To provide the ridge with the necessary strength, a cut can be made in half a tree: in this case, instead of a butt joint mating plane, the rafters are connected with a ledge. Next, a through hole is drilled for a stud or bolt with a diameter of 12 or 14 mm, nuts with wide washers are used for fastening.

If it is necessary to install sliding supports on the wall of the log house or create abutments (mating the rafters with the Mauerlat) with a certain degree of freedom, special attention should be paid to the ridge. It is recommended to make a movable joint assembly so that the roof does not deform with uneven shrinkage of the structure. For this purpose, the ends of the rafters are connected by a metal plate hinge.

Hip roof truss system units

A feature of the hip roof is the shape of its slopes: long slopes are trapezoidal, end slopes (hips) are triangular. Installation of such a rafter system requires the installation of diagonal (slant) rafter legs, which form triangular slopes. The principle of fastening diagonal rafters in the upper part depends on the structural features of the main part of the roof. It can be formed from hanging type trusses, or it can be a frame with a ridge girder and layered rafters attached to the Mauerlat.

If the layered rafter legs of the trapezoidal slopes rest on the ridge beam (girder), then the slant rafters must be supported on the ridge girder console. The outlets of the console behind the rafter frame should be 100-150 mm. The lower part of the diagonal rafter legs is attached to the Mauerlat or a beam fixed to the wall.

If the rafters need to be supported on the extreme hanging truss, then the principle of creating an attachment point depends on the section of the lateral rafter legs. A sprengel with a stand is mounted if the rafter legs are made of a board. The diagonal rafters rest on the sprengel. In a situation where a beam was used for the manufacture of rafter legs, the rafter rafters can be attached to the surf - a board with a thickness of 5 mm or more, fixed on the rafter truss.

On the slant rafters, a cut is made at an angle corresponding to the angle of inclination of the hip slope in order to ensure a tight connection with the sprengel or treadmill. For the strength of the nail connection, clamps and wire strands can additionally be used.

The shortened rafter legs (rafters) with the upper part rest on the slant rafter, with the lower one attached to the Mauerlat on the wall. The attachment point to the diagonal beam can be performed:

using the method of washing down with a nail fastener;
by means of a socket connection;
by attaching bars with a section of 50x50 mm on both sides and along the entire length of diagonal rafters and rafters.

Auxiliary elements

To enhance the rigidity and reliability of truss structures, it is often required to install a brace, an additional run or support posts. Runs for layered rafters allow you to provide the rafter leg with an additional point of support. The girder is a horizontal beam, fixed on vertical posts, parallel to the ridge. The attachment point is made using metal corner plates or an internal metal bar and an external straight bracket.

Wooden rafter braces reduce the span of rafter legs (including rafter rafters). The angle of inclination of the brace to the horizontal plane must be at least 45 °. If the rafter is made of a log or a bar, a strut is cut with a steel dowel installed at an angle of 90 ° to the abutment site, or the joint is closed from the outside with a plate.

If it is necessary to strengthen the roof frame, it is required to install a brace under each rack, on which the layered rafter rests. In this case, all the braces of one slope abut against a common bed. Brackets are used for fastening.

Special attention is required for the struts of the extreme spans, which are affected by the maximum snow and wind load. Fastening points when mounting the brace to the rack or purlin are made using pads and bolts.

The rafter system is the skeleton of the roof. It is she who is responsible for the strength of the roof, its reliability and resistance to loads. When building a house on your own, you need to know how to correctly make the attachment points for the rafter system so that the roof is reliable and safe.

The device of the rafter system

The rafter system consists of many elements, each of which performs its own task.

Mauerlats are responsible for the distribution of loads on the walls. These beams carry the weight of the entire roof and rest on the walls.
Rafter legs- these are inclined beams, which create the required angle of inclination of the roof.
Girders are horizontal beams that hold the legs together. There is a ridge run, located at the top, and side ones, located with the slopes.
The puffs are located horizontally and do not allow the rafter legs to part, forming rigid triangles with them.
Racks and struts(rafter legs) - additional elements on which the rafter legs rest. They run into the beds.
Lezhen - a horizontal beam under the ridge; racks and struts rest on it. The task of the bed is to redistribute the point load from the racks.
The ridge is the junction of the roof slopes.
Lathing - bars or boards that are stuffed perpendicular to the rafters. Roofing material is laid on it. The task of the crate is to distribute its weight.
Overhang - an elongated edge of the slope that protects the walls from precipitation. If the length of the rafter legs is not enough to create an overhang, additional elements are used - filly.

The structure of the rafter system is shown in the figure.

Also, roof trusses are distinguished in the roof structure. This is a solid knot consisting of rafter legs, stretch marks, struts and struts (braces, jibs). The truss can be not only triangular, but also trapezoidal, segmental or polygonal. Which type of farm to choose depends on the size of the house. If the distance between the walls is 9-18 m, then a triangular truss will do. For houses with a width of 12 to 24 m, trapezoidal or segmental trusses are used. If the width of the building is greater (up to 36 m), then polygonal trusses are used.

The main attachment points for the roof truss system are girder, ridge and Mauerlat.

Types of rafter systems

Rafters can be hanging and layered.

Hanging ones rest on the walls and create a spacer. To reduce it, tightens are made at the base of the rafters, which connect the rafters and form triangles with them. Hanging systems of various types are used for houses no more than 17 m wide. Depending on the width of the building, they are arranged in different ways.

If the width of the house is not more than 9 m, then the rafters are supported by a vertical bar - the so-called headstock. She is under the ridge.

If the width of the house is from 9 to 13 m, struts are additionally installed, which with one end abut against the rafter legs, and the other against the headstock.

With a house width of 13-17 m, two vertical posts are used, connected at the top with a crossbar (fitting), as in the figure.

Reinforced rafters rest on a load-bearing wall or columns inside the building. With this method, the rafter has three or more points of support. The rafter type of rafter system creates less stress on the walls of the building and is more durable; it is used for buildings of greater width. Such roofs can be arranged in different ways, depending on the location of the internal walls, they can be symmetrical or asymmetrical.

How to connect parts of the rafter system

To connect wooden elements with each other, nails, bolts, pins, as well as metal plates and corners are used to strengthen the nodes. Additionally, wooden blocks or plates are used.

Fastening methods:

teeth into a thorn,
teeth point-blank,
stop at the end of the crossbar.

The use of metal fasteners does not reduce the bearing capacity, since they do not need to be cut in, in contrast to fastening, for example, by the method of teeth in a tenon.

Rafters can be not only wooden, but also metal. For fastening metal rafters, various corners, brackets, perforated mounting tape, plates, bolts with nuts or self-tapping screws are used.

Mount to Mauerlat

If the wall is concrete, then a reinforced stiffening belt is made in its upper part, in which studs are provided. The Mauerlat will be attached to them.

Rafters to the Mauerlat can be attached in two ways: rigid and sliding.

The first method is more popular. For fastening, special corners with a support bar are used. There are several ways to attach the rafters to the Mauerlat.

Each rafter is nailed with three nails: two of them must be crossed, and the third is located vertically.
Fastening with a bracket: one end of it is hammered into approximately the middle of the support bar, and the other is turned 90 degrees and hammered into the rafter.
Fastening with wire rod: a clamp is made from a wire folded in 4 rows, with which the rafter is screwed to the bar. Instead of wire, a special perforated tape is also used. Sometimes this method is used in addition to other fastening methods.
Using corners: the corner is screwed to the Mauerlat and the rafter leg. It is better to use corners with two rows of holes and a stiffener.

The disadvantage of a rigid method is that when the building subsides, the walls may be damaged. Therefore, rigid fastening is used in brick buildings.

The sliding method implies that the rafters are connected to the Mauerlat with such fasteners that do not impede their movement within certain limits. This method is used in wooden buildings that can sink. With the help of special fastening methods, it is possible to achieve that the rafter will have one, two or three degrees of freedom. In the latter case, a special hinge is used.

One degree of freedom implies that the rafter can rotate in a circle. In this case, they are fastened with one nail or screw. The two degrees of freedom are circular rotation and horizontal offset. For this, the rafters are attached to the Mauerlat with metal brackets. Special skid angles are also used.

With a sliding joint in small buildings with a not very heavy roof, the fastening is done without cuts. If the building is large, it is recommended to make this knot with a saw cut on the rafter leg.

Important! The saw cut is cut precisely on the rafter, and not on the Mauerlat, so as not to damage or weaken the beam.

In this case, the fixation can be either rigid (with an emphasis on the beam) or movable (with a tooth on the outside). Sometimes, instead of sawing out the tooth, an additional bar is used.

Ridge connection

After the rafter leg is attached to the Mauerlat, they go to the ridge attachment point. This connection can be made in three ways: end-to-end, to ridge girder and overlap.

For end-to-end fastening, the rafters are cut in the upper part at an angle equal to the slope of the roof, and connected with nails (150 mm), driving them into the upper planes of the rafters, so that the nails enter the end of the opposite rafter. For strength, a metal plate or a wooden pad is attached, which is also nailed or bolted.

When attached to a ridge girder, a ridge beam (girder) is additionally laid between the rafters, this method is more laborious.

When overlapping, the rafters located on opposite sides go over each other and touch with their lateral surfaces. They are connected with bolts, nails or studs.

Beam node

The rafters are attached to the beams as follows. The main task of fastening is to prevent the rafters from sliding along the beam, therefore various techniques are used.

In the heel of the rafter, it is necessary to cut out a tooth and a spike, and a stop of the appropriate size is cut out in the beam.
The attachment point should be 25-40 cm away from the hanging edge of the beam.
The mounting socket should be 1/4 to 1/3 deep of the beam thickness.
Together with the tooth, a spike is cut out, which does not allow the rafter to move sideways. Such a connection is called a "spike and stop" tooth.

If the roof is flatter (its angle of inclination is less than 35 degrees), then the rafters are fixed in such a way that the area of their contact with the beam increases. Then use the following methods:

When creating a roof rafter system, it is important to remember the following.

Before installation, all wooden elements are treated with an antiseptic and a refractory compound.
The thickness of any wooden part should not be less than 5 cm.
Rafters without racks and struts are not made longer than 4.5 m.
Mauerlat should be placed strictly horizontally.
Racks and struts are recommended to be done as symmetrically as possible.
You cannot add elements to the calculated rafter system - this can lead to the appearance of loads where they are not needed.
At the junction of wood with stone (brick) masonry, waterproofing is needed.

A properly made rafter system is the key to the reliability of the roof. It is the rafters that bear the entire weight of the roofing materials and withstand wind loads. Therefore, it is very important to build a rafter system in compliance with the technology.

The rafter structure is the skeleton of the roof, which must take over and evenly distribute the weight of the roofing materials. If you correctly assemble a wooden frame for insulation, a waterproofing film and a topcoat, you can achieve a noticeable increase in the carrying capacity of the rafter system.

The main elements of the rafter system

The timber roof frame is assembled from parts such as:

Mauerlat - a kind of base for roofing elements, attached along the entire perimeter of the building to the upper edge of the outer walls in order to disperse the pressure of the roofing cake;
Mauerlat serves as the basis for the roof frame
rafter legs - irreplaceable parts of the wooden roof skeleton, which determine the angle of inclination of the slopes and the appearance of the upper part of the house;
ridge girder - a bar fixed in a horizontal position and, like a spine, connecting all the roof frame rafters in their upper part;
The ridge run is located exactly in the middle of the building
side girder - a horizontal bar, which differs from the ridge girder in that it is fixed in the middle of the rafter legs of each roof slope;
tightening - a spacer connecting two opposite rafters so that they do not part;
Tightening and braces are necessary to properly distribute the load on the Mauerlat
racks - vertical frame elements placed under the ridge and side girders in order to support the rafters and ridge beams, and also, if necessary, substituted under the middle part of the rafter legs;
Racks can support not only the ridge of the roof, but also the rafters
struts - parts resting on the bed, due to which the rafter legs become more stable;
log - a bar located on the upper edge of the inner wall of the building parallel to the ridge and serving as a platform for attaching racks and struts;
Lezhen is located on the inner wall parallel to the Mauerlat bar
roof ridge - the area where two slopes are combined, along which a solid lathing is installed, which is necessary to strengthen the described part of the roof;
The ridge is formed in the highest area of the rafter system
filly - elements used in the arrangement of the overhang, when the rafter legs are not long enough;
The filly lengthen the rafter legs
roof overhang - a zone of a wooden frame that protects the walls of the house from contact with a large amount of precipitation;
An eaves overhang is constructed to protect the walls from rain
sheathing - beams or boards, nailed perpendicular to the rafters and serving as a platform for attaching roofing materials.
Sheathing boards are laid out perpendicular to the rafters

Main connectors

The main nodes of the rafter system are:

rafter truss - connection of a rafter pair, stretch marks, as well as racks and braces;
ridge knot - combining two opposite rafters;
a link from a Mauerlat and a rafter resting on it;
a module that includes a girder, a rack and a bed;
connection of rafters with a strut and a rack.

The most complex link in the roof frame, according to the author, is a truss truss, which differs in that:

The ridge knot also has several features:

Rafters and Mauerlat become a single link, which is characterized by the following:

A module is formed from a purlin, a rack and a leg by driving construction brackets, steel pins or strips of steel strips into their joints.

The knot of the bed, the post and the purlin allows the load to be shared between the outer and inner walls of the building

The braces, posts and rafters are assembled into a single module, creating clearings. So that their connection is not weak, construction brackets are used.

A knot of struts, racks and rafters allows you to soften the pressure on the inner wall of the house

Methods for attaching rafters

In the lower part, the rafters can be connected to both the Mauerlat and the floor beams. Sometimes, for example, in frame construction, they are fixed directly to the wall. And in the upper part, the rafter legs are combined with the ridge. Each designated node can be created in several ways.

Mauerlat connection

The rigid fastening of the rafters to the Mauerlat guarantees the absence of any displacement of the assembly elements. It is performed by cutting in a certain sequence:

To speed up the work, a template is made from a piece of board or thick cardboard. A line is drawn on the workpiece, leaving a distance equal to 1/3 of the rafter width from the side edge, and then marking the point of contact with the Mauerlat bar, along which a second line is drawn, perpendicular to the first.
If the width of the rafter is more than 200 mm, then the cut is made at a depth of 70 mm
At an angle of inclination of the roof slope, the template is placed to the edge of the Mauerlat, making sure that the point marked on the piece of wood is strictly opposite the corner of the bar. Two lines are drawn from it with a pencil - vertical and horizontal, as a result of which a triangle is obtained on the workpiece, which is carefully cut out.
The prepared template is evaluated for correctness by placing it on the Mauerlat in several places. If the groove made is less or more than necessary, then the pattern is made anew, correcting the mistake.
The template is placed on a horizontal rafter. The triangle in the pattern is outlined with a pencil. Do the same with the other rafter legs. At the same time, make sure that the horizontal line of the groove in the pattern is in the same place of the rafter every time. Otherwise, the notches will be created at different distances from the ridge.
The triangles drawn on the rafters are cut out with a hand hacksaw. They act slowly with the tool, so as not to accidentally increase the depth of the groove in the rafter leg. With the skills of working with an electric saw, you can make grooves with this device. True, it must be borne in mind that a tool operating from the mains is much less obedient to the hand and is able to go to the side.
The triangular cut allows the rafter to rest against the Mauerlat
The correctness of the size of the grooves made is checked with a template. If inconsistencies are found, the notch is corrected with a hacksaw.
Two extreme rafter legs are placed on top of the house. They are inserted with grooves into the Mauerlat, fixing from the sides with metal corners or brackets.
A rope is pulled along the bottom edge between the two installed elements. Then the remaining rafter legs are attached to the Mauerlat one by one.

The technology of attaching the rafter legs to the Mauerlat with a stripe of a persistent bar can be taken into account by builders without experience. With this method of creating a knot, as the author of the article noted, it is possible to change the position of the rafters until it becomes completely correct.

To connect the main elements of the roof frame with the Mauerlat with a stripe of a persistent bar, do the following:

When building a roof frame for a wooden frame, which always shrinks, they prefer to use the sliding method of attaching the rafters to the Mauerlat. Thanks to him, it is possible to avoid deformation of the rafter structure and deterioration of the stability of the upper row of logs, which replaces the Mauerlat.

The choice of sliding rafters is justified only when a ridge beam is provided for the main elements of the roof frame, against which they could abut with their upper part.

When the rafters are fixed to the Mauerlat with a sliding method, certain steps are taken:

The forced method of attaching the rafters to the Mauerlat is adopted when the purchased lumber was shorter than necessary. Also, this method of fixing the main elements of the rafter system is used during the repair of a roof of a complex configuration.

When fastening the rafters to the Mauerlat using the layered method, only 3 tasks are performed:

Video: installing rafters

Alignment with floor beams

It is possible to fasten the rafters to the floor beams only being sure that the walls of the building will withstand the pressure of the roof frame. Still, in the absence of a Mauerlat, the load on the house is not uniform, but pointwise.

Without fear and doubt, the rafters are attached to the floor beams if they are building a light mansard roof. In this case, boards with a section of 5x15 cm are used as ceiling beams.

The rafters are not connected to the Mauerlat, but to the attic beams, if they know for sure that they will withstand the pressure exerted

To firmly fix the rafter legs on the floor beams, perform the following tasks:

Wall mount

If, for some reason, the rafters have to be fixed directly on the walls, then they will definitely need to be tightened. She, as the author of the article, who helped build the roof of the utility room, was personally convinced, will remove from the house some of the stress transmitted by the rafter legs.

In no case should the rafters be directly connected to the outer walls of the building if they are built of foam or aerated blocks. These materials freely transfer their moisture to the wood and are unable to retain the fasteners.

On the wall, the rafters can be fixed with a sliding method, but this is not the most reasonable solution.

In order to securely fix the rafter legs on the walls, it is necessary to take certain measures:

At the right angle, make a wash down on the rafters with one tooth.
Install the rafters on the walls with their butt ends and drive a nail 10–12 cm long into them.
If necessary, attach metal corners to the sides of the rafters.

Since the ridge of the roof is under severe pressure from the entire rafter system, experienced roofers create a ridge knot in five ways: end-to-end, on a beam, overlapping, in a groove, in a half-tree.

To create a ridge knot by joining opposite rafters butt-to-end, do the following:

When attaching the rafters to a beam, or rather, to a special ridge girder, they act in a special way:

When the rafters are connected to the beam, the ridge is not spiky, but flat.

If the ridge knot is made by fastening the rafters with an overlap, then you will need to perform several simple tasks:

To connect the rafter legs into a ridge knot using a groove, several skillful carpentry actions are performed:

Having chosen the method of connecting rafters in half a tree, do the following:

Video: construction of a roof frame with a ridge girder connection

You should not start the construction of the rafter system until you can figure out the features of attaching the rafters to other elements of the roof supporting structure. By the way, among the various methods of fixing rafter legs, there are options not only for experienced builders.

In any building, the main elements to which the maximum load falls are the foundation, walls and roof. The quality of the installation of the roof largely depends on whether the truss system is installed correctly or not. If the attachment points of the rafter system do not meet certain requirements, then such a roof will not serve even the minimum operational life without repair work.

Requirements for the rafter system

The rafter system of any roof must meet such important requirements as:

Maximum rigidity. Any node of the frame must withstand the load without being subjected to deformation or displacement. The triangle obtained when arranging the rafter system must ensure the rigidity of the structure, and its maximum stability;
Optimal weight. Depending on the roofing material, the material used for the rafters is selected. Timber is usually chosen, but metal can be used for heavy roofs.
Important! To prevent damage to the rafters, their rotting and the formation of fungus on the wood, it is treated with an antiseptic, and metal structures - with anticorrosive compounds.
High quality materials used. The wood used as rafter legs should be free from cracks and chips.

Varieties of rafter systems

The roof can be equipped with one of the types of rafter system, of which there are only two:

Hanging rafters;
Roof rafters.

Hanging rafter system

Such a system is optimal in the case of a gable roof, when the span between the walls is no more than 6 meters, but when installing additional elements it is also applicable for wider openings. The Mauerlat serves as the lower base for the support, while the upper part of the structure abuts against each other. Such a design also contains a tightening - necessary to relieve the load from the walls, by reducing the spacing of the rafters. Beam braces are installed below the rafter legs and can function as floor beams.

Attention! The role of tightening can not necessarily be performed by a wooden beam, it can also be a floor made of reinforced concrete structures, which in some houses is equipped with the upper floor.

If the tightening is located above the bottom of the rafter system, then it is called a deadbolt. The important points of arranging a rafter system of this type include:

It should not be allowed that the roof overhang rests on the lower part of the rafter legs, which are displayed outside the wall. In such a situation, it is best to use a filly (the width of the overhang is set within one meter). With this arrangement, the rafter will rest on the Mauerlat. The cross-section of the timber for the filly is chosen smaller than for the rafters;
To give the roof additional rigidity, and prevent it from wobbling and destruction by strong gusts of wind, a wind board is nailed to the slope, to the Mauerlat from the ridge;
When the moisture content of the material used to equip the rafter system is more than 18%, precariousness should be provided, which will cause the wood to gradually dry out. This is why fasteners should be bolted or screws and not nails.

Roof rafter system

This arrangement is applicable for roofs with wall spacings from 10 meters (maximum 16 meters). The slope can be made at any angle, and there are load-bearing walls or supporting columns inside the building. From above for the rafters, the ridge girder serves as the main support, and from below this function is performed by the Mauerlat. The inner girder is supported either by the inner wall or by the posts. Due to the presence of only vertical type of loads, there is no need to mount the tightening.

With a 16-meter span, the ridge run is replaced by two side structures, which will be supported by racks.

Important! The absence of bends of the rafter legs is ensured by such nodes as struts and crossbars.

Particular attention to the arrangement of the roof using a layered rafter system should be paid to the following nuances:

Features of calculations of the gable roof rafter system are shown in the video:

The main nodes of rafter systems

The main nodes of the roof truss system include:

Rafters. They function as a skeleton, supporting the internal and external elements of the roof, and also serve as the basis for laying communications;
Mauerlat. This is a kind of roof foundation, which is a beam on which the entire structure is installed. It performs an important function - even distribution of the load of the entire structure;
Run. Designed for fastening rafter legs together and can be located both from above and from the side;
Tightening. Serves to fix the rafters at the bottom of the structure;
Braces and struts. Provide the most stable location of the rafter beams;
Skate. The junction of the roof slopes;
Filly. These are the extensions of the rafter legs, which are sometimes equipped;
Rigel. It is necessary for high-quality and reliable support of load-bearing elements;
Sill. Crossbar required for load distribution.

In addition to the listed elements, the structure includes attachment points for the roof truss system. When performing them, it is imperative to follow certain rules.

Important! It is absolutely not worthwhile to carry out a simple fastening of the base to the crossbar, as this can lead to the complete destruction of the rafter system.

The following types of fasteners should be used:

With emphasis on the end of the crossbar;
Teeth point-blank;
Teeth into a thorn.

The number of teeth should be chosen depending on the slope of the slope, and additional structural reliability can be created using metal corners.

Description of the main fasteners for the installation of the rafter system

If in the process of building a house a rounded log or timber was used, then it is not necessary to create an armored belt. produced on the upper bar or on the wall log. For this purpose, the connection of the Mauerlat with the rafters, different methods of cuts (cuts) are used.

What fasteners are used to fasten metal rafters:

Plates.
Fasteners LK.
Corners.
Brackets WВ.
Self-tapping screws.
Varieties of the corner of the Kyrgyz Republic.
Wire ties.
Perforated mounting tape TM.
Bolts with nuts.
Brackets WВ.

If brackets are used when connecting the rafters to the Mauerlat, then they are not cut into the rafters, which helps to strengthen the bearing capacity. Usually, metal brackets are produced, and the metal is galvanized and has a thickness of 0.2 cm. Brackets are reinforced with nails, anchor bolts or screws.

You can use the LK fastener by creating attachment points not only for rafters with a Mauerlat, but also for other various elements that make up the roof structure. The LK fastener is anchored to wood, just like the brackets, with the exception of the use of anchor types of bolts.

Mounting perforated tape allows you to strengthen the connecting nodes when erecting roofing systems. It is used not only to create stronger nodes, but also to strengthen the elements for additional use in order to give rigidity or strength to the system as a whole. The perforated mounting tape is fastened with screws or nails, therefore it is used to strengthen the structure of the rafter system of any roof, the integrity of which will not be violated.

Using the corners of the KR and their various modifications, the attachment points are reinforced so that they can effectively participate in the connection of the Mauerlat and the rafters. Providing adequate strength to the nodes of the roof is permissible when using corners, which makes it possible to increase the load-bearing characteristics of the roof structure.

The use of metal connecting elements is not associated with cutting corners into the roofing system. This will not reduce the load-bearing capacity of the roofing system. You can use corners for connection using screws or nails, the protrusions of which resemble a ruff.

How are the knots connected in the ridge part?

There are three main types of fastening in the ridge parts of the roofing system:

Butt joint.
Fastening based on a ridge girder.
The ridge joint is overlapped.

For the purpose of fastening, in the first way, the ridge part is cut from the upper edge at an angle that is the same as the angle of the roof slope. Then it is resting against the necessary rafter, which must also be cut at an angle, but on the opposite side of the roof. A special template is sometimes used to trim the corners.

The nails for connecting the rafters under the ridge must be 150 mm or more, two of them are needed. Each nail is driven into the rafters at the top of the rafters at the appropriate angle. The sharp end of the nailed nail usually goes into the rafter cut from opposite sides. Strengthening the ridge joint can be achieved by placing a metal plate on the side or a wooden lining on it so that it is enough to tighten it with bolts or nails.

The connection in the second way, that is, through the ridge girder, is associated with the strengthening of the rafters on the ridge beam. A purlin is one of the additional support beams or beams, which is a support for the rafters. It is located parallel to the ridge or Mauerlat. The method differs from the previous one in that a ridge beam is laid between the rafters, which are cut at an angle, which is a laborious process, therefore this method is used less often.

A more common method is similar to the first, but it differs in that the fastening is made with an overlap, and the joint method is not used. At the same time, the rafters should touch the ends, not the side surfaces. Tighten the rafters with a bolt or hairpin, nails. This connection is used by many masters in practice.

In general, it is possible to install rafters on a Mauerlat by creating structures of roofing rafter systems that are spacer or non-spacer. This determines the choice of the appropriate method of connecting the Mauerlat and the rafters, which can be similarly reinforced to the ridge.

The main shortcomings in the installation of attachment points for the rafter system

The problem of choosing the method of attaching the rafter system to the structure of the building is very important when creating attachment points. Often, when creating knots, the Mauerlat serves as a support for the rafters. The Mauerlat bar is fastened “tightly” with anchor bolts to the reinforced stiffening belt.

A possible drawback is an unanchored stiffening belt, which can lead to overturning of the Mauerlat beam and a violation of the stability of the roof truss system. Roof loosening occurs, and the roof slides down at the same time. The fastening is no longer effective due to incorrect placement of the anchor bolts or incorrectly drilled holes.

If the nuts are overtightened onto the bolts, then the attachment point becomes fragile and undergoes rapid destruction. In this case, wire twisting is sometimes used to create a fastening point.

During the construction of the rafter system, the safety of the connections must be observed.

For example, if a rafter structure is combined with a ceiling without taking into account the bearing capacity of the attic floor, then this is the most dangerous moment that can lead to the destruction of the building.

If the tightening is changed to a prefabricated reinforced concrete floor beam designed for bending, then the use of precast concrete beams should be effective due to their rigid fastening in a reinforced floor stiffening belt, which is arranged using a reinforcing cage. Its axis should go in the same direction as the acting forces.

At the same time, the presence of shortcomings in the process of creating a rafter system, which is a load-bearing wooden floor structure, often arises due to a misunderstanding of the functions performed by a tightening and a bolt in the entire roofing system. The tightening differs from the girder in that it is a longitudinal, and the girder is a transverse beam.

The construction of the rafter system is associated with the creation of a spacer system operating on the principle of divergence at the bottom of the planes, which occurs under the influence of not only their own weight, but also the load that falls on the line of intersection of the planes, which should be prevented by the cross beam, that is, tightening.

When starting to build a roof, you should find out all the points associated with making certain mistakes that arise when working on the construction of a rafter system. The device of the roof of the house is associated with possible difficulties and shortcomings that do not allow achieving the set goal.

Mauerlat is one of the main elements of the roof structure. The rafters are attached to it. The operational period of the entire roof depends on the high-quality creation of the truss structure.

The main methods of supporting rafters

There are several technologies for supporting the rafters on the Mauerlat. It is possible to carry out rigid fixation of the structure. It does not allow any displacement of the rafter leg. To do this, use a hemming beam, thanks to which the rafters are prevented from sliding at the point of support, and metal corners, which eliminate any lateral shift of the structure.

The rafter foot sliding joint is used in wooden houses. Moreover, the main element for its emphasis is the upper crown, and not the Mauerlat. To prevent damage to the roof, the support unit for the rafters is made as free as possible. To do this, use a sliding support, which, when the log shrinks, is displaced along a guide fixed on the leg.

The sliding bearing unit can be made using a different technology. A gash is made in the rafters, which should adjoin the upper rim of the log house. For fixing the beams, it is permissible to use any fasteners: staples, nails or steel plates.

Fasteners for installation work

In order to qualitatively connect the rafters with the Mauerlat, you will need materials and tools such as:

dry timber;
boards;
axe;
hacksaw;
hammer;
roulette;
plumb line;
level;
screwdriver;
drill;
Bulgarian.

Particular attention should be paid to the availability of all fasteners. The fixing of the beams is done with galvanized steel beam brackets, which do not reduce the load-bearing capacity of the structure. There is no need to cut the brackets into the beams.

You also need to buy perforated mounting tape, which will strengthen the Mauerlat nodes. With its help, a strong connection of all structural elements is made. The tape also does not cut into the beams. For its reliable fixation, nails and self-tapping screws are used.

In addition to brackets and perforated tape, in order to securely support the rafters to the Mauerlat, you should purchase:

universal bar connectors;
fasteners for rafters;
embedded supports;
wire rod;
steel corners;
rack mountings;
self-tapping screws;
nails;
staples;
plates;
galvanized nails;
studs with washers and nuts;
anchor bolts.

Create a ridge and install the bottom of the rafters

Installation work begins with the ridge part of the roof structure. You can install the rafters in one of three ways:

end-to-end;
to run;
overlap.

The butt joint of the structure involves cutting the upper part of the rafter leg. This is done at an angle that is equal to the slope of the roof slope. On the skate, a pair of legs are connected. To obtain the same support unit for the Mauerlat elements, you should use a ready-made template.

A feature of fixing the rafters to the run is the presence of a ridge beam. This option for arranging the Mauerlat is highly reliable. But often such a rafter support system provides for the installation of additional supporting structures, which will lead to a decrease in the functionality of the attic. Naturally, this method is not suitable for small roofs.

The technology for installing rafters with an overlap is in many ways similar to their installation on a ridge girder. The main difference is that the connection of the upper legs is overlapped. This leads to a strong connection of the structure, since the studs hold two elements at once.

The connection of the lower ends of the rafters is carried out depending on the material of the walls. In the presence of wooden housing construction, the upper trim of the wall can act as a supporting element. If foam blocks (or aerated concrete) were used during the construction of the house, then the rafters are supported on the Mauerlat.

The device of a reinforced reinforced concrete belt is the optimal solution in the case of using masonry building materials. This technology does not provide for the creation of any methods of fixing the rafter system. Vertically located anchor bolts act as fasteners for the timber. The main thing is that when pouring concrete mortar, the pins are located in a strictly vertical position.

Connection of rafters with beams and Mauerlat

After fixing the top and bottom of the rafters, they should be fixed to the beams. It is clear that you can connect the rafters to the beam with just nails. But this is not the best solution. Such a mount will not be as reliable as possible. To prevent slipping of all elements, the fixing of the rafter structure to the beams takes place by using the “spike” and “tooth” connections.

If there is a steep roof slope (more than 35º), one-tooth cutting technology is used. At the bottom of the rafter, a tooth with a spike is made. Nests created in the beam should have a depth of 30% of the beam thickness. The device of rafter connections is carried out at a distance of 0.3-0.4 m from the extreme part of the beam. This prevents the beams from chipping due to the heavy load from the leg pressure.

When arranging a roof with a slope of up to 35º, the rafters are installed by expanding the interface area of the main structural elements. Usually the rafter leg is covered with a beam. For this purpose, holes for two teeth are cut in the rafter leg:

thorn with an emphasis;
one more emphasis.

The depth of the cut when fixing the rafters to the beam is within 30% of the beam thickness.

Better connections can be obtained by using bolts or clamps. This technology involves the use of wire loops, with the help of which the assembly is fixed to the anchor bolts located in the wall of the building.

Leaning on the Mauerlat is the most common option for securing the bottom of the rafters. A cutout of such a size is made in the rafter leg so that it can be easily put on the Mauerlat without any problems. Otherwise, during the operation of the roof, the bar may move.

In some cases, the Mauerlat must be “equipped” with a reverse recess. It depends on the type of wood from which the bar is made. If hardwood was used for its production, a slot is made, which, in combination with the recess of the rafters, will create a locking element. When making coniferous beams, a cutout is not required, as it will weaken the structure.

The most acceptable option for a Mauerlat is a rigid coupling of the rafter system.

This technology can be done in one of two ways:

using hemming bars and corners made of metal;
by installing saddles on the rafters.

The first option is that a support bar is used to place the rafters on the Mauerlat. Rigid support of the rafter leg is made. Reliable fixation of the structure is carried out with metal corners. This prevents lateral movement of the structure.

The second option is more popular. For fasteners, nails are used that are directed towards each other and hammered in at an angle. Two hammered nails are crossed. Then another nail is driven in. The third nail should be in an upright position. The fastening unit made will be characterized by maximum rigidity if additional fastening is carried out using a wire rod.

At the beginning of the attic roof planning, a rafter system is selected to serve as a supporting structure. The type of truss system required is determined based on the type of roof.

Depending on the system chosen, these can be wooden beams used as a roof frame that holds the composite building materials of the entire structure, or concrete elements that create supports, called rafter legs. Before starting work, the wooden components are impregnated with special compounds that protect the roof from fire and decay. The durability of the roof directly depends on the quality of this procedure.

Varieties of rafter systems and the device of their nodes

The rafter system is divided into two main types: layered and. Since the joints in each of the systems have different characteristics, a certain type of rafter is selected based on the properties of the preferred roof, including its architectural features.

The main factors when choosing the right type of system:

general roof functionality;
pressure force of roofing building materials on the structure;
the prevalence and frequency of precipitation in the territory where the house is located.

The hanging type of rafters does not have supports located in the gaps. For this reason, a reinforced thrust appears, which is transmitted horizontally to the walls of the structure. To reduce this indicator, a tension member made of wood or metal is introduced into the support assembly, designed to combine the rafter legs. Thus, the knots of the hanging rafters acquire the shape of a triangle. The tightening element is located at the base of the legs, it acts as a crossbar (most often used in gable roof structures) and works in bending and compression. The strength of the connection with the base of the supports depends on the height of the tightening element.

The overlapping type of rafters is often set up in buildings where there is a central support column or load-bearing wall. The rafters rest their limbs against the sides of the building, and the central part rests on a column or other support inside the house. Such a structural unit is designed for bending function. Inclined supports create less stress on the components of the building, so their installation is not as laborious as in the case of hanging rafters. In addition, it does not require large material costs.

There are also options for arranging the roof, combining both types of rafters. In this case, each type alternates, that is, areas without bearing walls are equipped with hanging rafters, and areas with the necessary supports are layered.

Competent arrangement of the rafter system

The main factor in the high strength of the roof in the future construction is the competent arrangement of all nodes and anchor points.

In the case of layered rafters, at least 3 support points are assumed for the attic roof. This value can change if the span exceeds the standard limits. For example, if the span is no more than 10 m, only one additional support is required.

The hanging leg assembly is assembled based on span dimensions. On small spans, the latching element is most often replaced by a deadbolt. With large span sizes, the latching elements sag, and the supports go into bending.

Thus, dangling nodes can have the following differences in relation to the span size:

Figure 1. Diagram of the device Mauer.

9 m. Supports must be restrained with a wooden block installed perpendicular to the attic floor. In the area of the base, it is reinforced with staples, and the tightening elements are fastened with special clamps.
13 m. Fastening is carried out using struts, which abut against the top with the top, and with the lower part against the perpendicular beam. The spacing between the supports should not be more than 5.5 m.
17 m. The base must be reinforced with special devices. For the top, a truss structure is used: the tightening elements are attached to two wooden bars, and a crossbar is mounted between them.

Knot fastening methods

Regardless of whether the existing truss system needs to be replaced or built from scratch, a certain set of rules must be followed when fixing its nodes.

First of all, the simplest fastening of the crossbeam and the base of the support should be avoided, as this can have a devastating effect on the entire roofing system.

Figure 2. Attaching the rafter leg to the Mauerlat.

In other words, from the load created by building materials or atmospheric precipitation, the ends of the supports slide off, and the rafter system is damaged. This leads to its complete collapse. To prevent such an outcome, it is necessary to improve the reliability of these nodes. This is achieved using the following types of fastening:

teeth in a tenon;
teeth point-blank;
emphasis on the end of the crossbar.

One or two teeth can be used depending on the slope. To increase the reliability of the connection, you can create additional fasteners using metal corners.

Roof lathing attachment points

The main attachment points for the rafter system are:

beam;
mauerlatny;
ridge.

Beam attachment point

Figure 3. Diagram of the ridge connection of the rafter system.

In the rafter leg, teeth are created into a tenon, and a socket is cut out in the crossbar, which corresponds to the cut teeth. In this case, the socket should occupy no more than 30% of the entire thickness of the crossbar.

If, during the construction of the roof, lightweight materials were used, and its slope is less than 35 °, the bases of the supports are placed so that the area of their stop is much larger than the beam. This can be achieved by using a two-toothed 2-stud insert, a stop (with or without a stud), and two studs in the lock.

The system nodes are fastened either with hardware with metal corners, or wood blocks, linings and spikes.

Mauerlat mount

There are 2 technologies for Mauerlat support fastening: rigid and sliding (Fig. 1).

In the first case, a strong connection is established between the rafter and the Mauerlat without the possibility of sliding, bending and jumping out. This is achieved by placing special corners with a support bar. The formed knot must be fastened with a reliable wire using hardware. The nails are driven in at a certain angle from the side so that they are in a crossed state in the Mauerlat. The last nail is nailed vertically. This method is the most popular.

In the second case, the fastening is carried out using a special mechanism that allows a certain element (in this case, the rafter) to move in the desired direction (Figure 2).

To create such a connection, you will need to make a tie-in on the supports, and then lay them on the Mauerlat. As in the previous case, both parts of the knot are secured with two crossed nails and one vertical at the top. The boards are fixed to the Mauerlat with metal brackets. After that, the support base is released behind the wall and fastened with plates and sleds. Thus, the emphasis is on the Mauerlat, but all components of the rafter system can move within acceptable limits.

This method is most often used when erecting a roofing system of wooden buildings (logs, frame), which are characterized by subsidence. It is worth remembering that with a rigid mount there is a possibility of damage to the walls of the structure.

Ridge attachment point

Such a knot can be created in two ways: butt and overlap (Fig. 3).

The first method involves trimming the tops of the supports at the same slope as the corner of the roof. They are resting on opposite supports, which also need to be trimmed. The fastening is created with two nails (150 mm), hammered from above at a certain angle, so that they are adequately positioned inside each rafter. To increase reliability, the seams between the supports are fastened with wooden plates or metal plates.

The second method is the most popular. It differs from the first method by the overlapping method. In this case, the supports are connected not by the ends, but by the side parts, after which they are fixed to the bolts.