Construction of the roof truss system. Types of gable roof rafter system: for small and large houses Rafters from boards assemblies

At the heart of every roof is a large number of beams, rafters, posts and purlins, which are collectively called the rafter system. Over the centuries-old history, many types and methods of its organization have accumulated, and each has its own characteristics in the construction of nodes and cuts. Read more about what a rafter system can be gable roof and how the rafters and other elements of the system should be attached, let’s talk in more detail.

Design of a gable roof truss system

In cross-section, a gable roof is a triangle. It consists of two rectangular inclined planes. These two planes are connected at the highest point into a single system by a ridge beam (purlin).

Now about the components of the system and their purpose:

Mauerlat is a beam that connects the roof and walls of a building, serves as a support for rafter legs and other elements of the system.
Rafter legs - they form the inclined planes of the roof and are the support for the sheathing under roofing material.
Ridge purlin (bead or ridge) - combines two roof planes.
A tie is a transverse part that connects opposite rafter legs. Serves to increase structural rigidity and compensate for thrust loads.
Lezhny - bars located along the mauerlat. Redistribute the load from the roof.
Side purlins - support the rafter legs.
Racks - transfer the load from the purlins to the beams.

There may still be fillies in the system. These are boards that extend the rafter legs to form an overhang. The fact is that to protect the walls and foundation of the house from precipitation, it is desirable that the roof ends as far from the walls as possible. To do this, you can take long rafter legs. But the standard length of lumber of 6 meters is often not enough for this. Ordering non-standard is very expensive. Therefore, the rafters are simply extended, and the boards with which this is done are called “fillies”.

There are quite a few designs of rafter systems. First of all, they are divided into two groups - with layered and hanging rafters.

With hanging rafters

These are systems in which the rafter legs rest only on the external walls without intermediate supports (load-bearing walls). For gable roofs the maximum span is 9 meters. When installing a vertical support and a strut system, it can be increased to 14 meters.

Hanging type rafter system The good thing about a gable roof is that in most cases there is no need to install a mauerlat, and this makes the installation of rafter legs easier: there is no need to make cuts, just bevel the boards. To connect the walls and rafters, a lining is used - a wide board, which is attached to studs, nails, bolts, crossbars. With this structure, most of the thrust loads are compensated, the impact on the walls is directed vertically downwards.

Types of rafter systems with hanging rafters for different spans between load-bearing walls

Gable roof rafter system for small houses

There is a cheap version of the rafter system when it is a triangle (photo below). Such a structure is possible if the distance between the external walls is no more than 6 meters. For such a rafter system, you can not make calculations based on the angle of inclination: the ridge must be raised above the tie to a height of at least 1/6 of the span length.

But with this construction, the rafters experience significant bending loads. To compensate for them, either rafters of a larger cross-section are taken or the ridge part is cut in such a way as to partially neutralize them. To give greater rigidity, wooden or metal plates are nailed on both sides at the top, which securely fasten the top of the triangle (also see the picture).

The photo also shows how to extend rafter legs to create a roof overhang. A notch is made, which should extend beyond the line drawn from the inner wall upward. This is necessary to shift the location of the cut and reduce the likelihood of the rafter breaking.

Ridge knot and fastening of rafter legs to the backing board when simple version systems

For mansard roofs

Option with installing a crossbar - used when. In this case, it serves as the basis for lining the ceiling of the room below. For reliable operation systems of this type, the crossbar cut must be hingeless (rigid). The best option- half frying pan (see picture below). Otherwise, the roof will become unstable to loads.

Please note that in this scheme there is a Mauerlat, and the rafter legs must extend beyond the walls to increase the stability of the structure. To secure them and dock them with the Mauerlat, a notch is made in the form of a triangle. In this case, with an uneven load on the slopes, the roof will be more stable.

With this scheme, almost the entire load falls on the rafters, so they need to be taken with a larger cross-section. Sometimes the raised puff is reinforced with a pendant. This is necessary to prevent it from sagging if it serves as a support for ceiling cladding materials. If the tie is short, it can be secured in the center on both sides with boards nailed to the nails. With a significant load and length, there may be several such belays. In this case, too, boards and nails are enough.

For large houses

If there is a significant distance between the two outer walls, a headstock and struts are installed. This design has high rigidity, since the loads are compensated.

With such a long span (up to 14 meters), it is difficult and expensive to make the tie in one piece, so it is made from two beams. It is connected by a straight or oblique cut (picture below).

For reliable joining, the connection point is reinforced with a steel plate mounted on bolts. Its dimensions must be larger than the dimensions of the notch - the outer bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the notch.

In order for the circuit to work properly, it is necessary to make the struts correctly. They transfer and distribute part of the load from the rafter legs to the tie and provide structural rigidity. Metal pads are used to strengthen connections

When assembling a gable roof with hanging rafters, the cross-section of lumber is always larger than in systems with layered rafters: there are fewer load transfer points, therefore each element bears a greater load.

With layered rafters

In gable roofs with layered rafters, their ends rest on the walls, and middle part rest on load-bearing walls or columns. Some schemes push through the walls, some don't. In any case, the presence of a Mauerlat is mandatory.

Non-thrust schemes and notch units

Houses made of logs or timber do not respond well to thrust loads. For them they are critical: the wall may fall apart. For wooden houses The rafter system of a gable roof must be non-thrust. Let's talk about the types of such systems in more detail.

The simplest non-thrust rafter system diagram is shown in the photo below. In it rafter leg rests on the mauerlat. In this version, it bends without pushing the wall.

Pay attention to the options for attaching the rafter legs to the Mauerlat. In the first, the support area is usually beveled, its length being no more than the section of the beam. The depth of the cut is no more than 0.25 of its height.

The top of the rafter legs is laid on ridge beam without fastening it to the opposite rafter. The structure turns out to be two pitched roofs, which in the upper part are adjacent (but not connected) to one another.

The option with rafter legs fastened at the ridge part is much easier to assemble. They almost never push against the walls.

To operate this scheme, the rafter legs at the bottom are attached using a movable connection. To secure the rafter leg to the mauerlat, one nail is driven from above or a flexible steel plate is placed from below. See the photo for options for attaching rafter legs to the ridge girder.

If you plan to use heavy roofing material, it is necessary to increase the load-bearing capacity. This is achieved by increasing the cross-section of the rafter system elements and strengthening the ridge assembly. It is shown in the photo below.

Reinforcing the ridge assembly for heavy roofing material or for significant snow loads

All of the above gable roof schemes are stable in the presence of uniform loads. But in practice this practically never happens. There are two ways to prevent the roof from sliding towards a higher load: by installing a screed at a height of about 2 meters or by struts.

Options for rafter systems with contractions

Installing contractions increases the reliability of the structure. In order for it to work properly, it needs to be secured to them with nails at the places where it intersects with the drains. The cross-section of the timber for the scrum is the same as for the rafters.

They are attached to the rafter legs with bots or nails. Can be installed on one or both sides. See the figure below for attaching the screed to the rafters and ridge girder.

In order for the system to be rigid and not “creep” even under emergency loads, it is enough in this option to ensure rigid fastening of the ridge beam. In the absence of the possibility of its horizontal displacement, the roof will withstand even significant loads.

Layered rafter systems with struts

In these options, for greater rigidity, rafter legs, also called struts, are added. They are installed at an angle of 45° relative to the horizon. Their installation allows you to increase the span length (up to 14 meters) or reduce the cross-section of beams (rafters).

The brace is simply placed at the required angle to the beams and nailed on the sides and bottom. An important requirement: the strut must be cut accurately and fit tightly to the posts and rafter leg, eliminating the possibility of it bending.

Systems with rafter legs. The top is a spacer system, the bottom is a non-spacer system. The correct cutting nodes for each are located nearby. At the bottom - possible schemes strut fastenings

But not in all houses the average load-bearing wall is located in the middle. In this case, it is possible to install struts with an angle of inclination relative to the horizon of 45-53°.

Systems with struts are necessary if significant uneven shrinkage of the foundation or walls is possible. Walls can settle differently depending on wooden houses, and the foundations are on layered or heaving soils. In all these cases, consider installing rafter systems of this type.

System for houses with two internal load-bearing walls

If the house has two load-bearing walls, install two rafter beams, which are located above each of the walls. The beams are laid on the intermediate load-bearing walls, the load from the rafter beams is transferred to the beams through the racks.

In these systems, a ridge run is not installed: it provides expansion forces. The rafters in the upper part are connected to one another (cut and joined without gaps), the joints are reinforced with steel or wooden plates, which are nailed.

In the upper non-thrust system, the pushing force is neutralized by the tightening. Please note that the tightening is placed under the purlin. Then it works effectively ( top diagram on the image). Stability can be provided by racks, or joints - beams installed diagonally. In the spacer system (in the picture it is below) the crossbar is a crossbar. It is installed above the purlin.

There is a version of the system with racks, but without rafter beams. Then a stand is nailed to each rafter leg, the other end of which rests on the intermediate load-bearing wall.

Fastening the rack and tightening in the rafter system without a rafter purlin

To fasten the racks, 150 mm long nails and 12 mm bolts are used. Dimensions and distances in the figure are indicated in millimeters.

In order for the roof to have high strength and reliability, special attention will need to be paid to the rafter system. In addition to correctly performed calculations and drawings, fasteners for rafters and all its elements are of no small importance in the stability of the structure.

Construction of the rafter system.

In addition to the load of precipitation, the rafters must withstand the weight of the sheathing and total weight roofing pie, which must be taken into account when selecting fastenings.

The rafter system is spatial design, consisting of the following elements:

In order to understand how all parts of the rafter system are attached to each other, you need to understand what components it consists of, what fasteners are used in each case and what they are. During assembly load-bearing structure Roofs use fastening elements, both steel and wood.

Main connection points of the rafter system

Scheme for attaching the Mauerlat to the wall.

Before connecting the Mauerlat and the rafter leg together, the first will need to be firmly connected to the wall. The Mauerlat is a thick beam (15x15), laid along the axis of the wall and parallel to the ridge of the beam, on which the rafter legs rest. The assigned functions of this element of the supporting structure are to distribute the load from the rafters, the weight of the roofing pie and precipitation throughout the entire wall, including internal supports. In other words, the foundation for the entire roof is the Mauerlat. It is laid on the axis of the wall and secured to it. In this case, there are several connection methods.

Method one. When installing a roof of a large area, an armored belt is poured along the entire length of the wall, into which metal pins are immediately embedded for the M12 thread every 2 m. this method As a fastener for the Mauerlat to the wall there will be studs that pass right through the beam and are attracted to the wall using a nut and washer. At small area roofs where there is no heavy load on the wall are dispensed with without a mauerlat and the rafters are attached directly to the studs embedded in the masonry process.

Method two. Another one quite affordable way To make the rafter system stable is to attach the Mauerlat to the wall using wire. To do this, you will need to lay the middle of the wire between the rows of bricks 3 rows before the end of the masonry. Its length should be sufficient to tie and pull the Mauerlat to the wall. You can also do without a Mauerlat and secure the rafter with wire directly to the wall. But such a connection will give a point load on the wall, which can affect its integrity

The pattern of attaching the rafter leg to the mauerlat can be rigid or sliding. The type of connection depends on the shape of the roof and the type of rafters, which can be hanging or layered.

Rigid and sliding connection of the lower part of the rafters with the Mauerlat

Main components of roof trusses.

The connection nodes in this case will be made of wood and can have several types:

A tooth that has only an abutment.
A tooth that has a spike and a stop.
The emphasis is directly on the beam.

A single tooth notch is used for roofs with a large angle of inclination, where the angle between the mauerlat and the rafter is more than 35º. To do this, you will need to cut out a tooth with a spike in the rafter leg, and create a nest for it in the mauerlat. The use of a tenon allows you to avoid lateral displacement of the rafters. The double tooth notch is used when installing flatter roofs. The latter method is used extremely rarely.

Lately, more and more often wooden mount for rafters is replaced by metal, since it allows not only to obtain more reliable design rafter system, but also significantly reduce the work on its installation. Therefore, metal rafter bolts, staples, plates, clamps, hinges and various corners are used as additional fasteners.

Example of a sliding connection...

The most used method of rigid connection is driving nails from the sides at an angle into the mauerlat. Thus, internal crossing occurs within it. Next, to finally secure the connection, a third nail is driven vertically. Another way to prevent lateral displacement of the rafter leg is to secure it on the sides with metal corners.

The scheme for movable fastening of rafters in the lower part is used for houses built from rounded logs or timber. Since during operation the rafter system is in motion due to changes in its physical properties, i.e. the building shrinks.

A rigid fastening scheme in this case is unacceptable, since such movements can lead to the destruction of the wall. This means that the fastening points need to be flexible. In such cases, special hinge joints are used, which are called slides or corners with an oblong hole for fasteners. The sliding interface in this mount achieves two levels of freedom by free movement one of the fastening elements.

Nodal ridge connection

The ridge connection of the rafter system can be obtained in three ways: end-to-end, overlapping and on a ridge beam.

Scheme of the ridge connection of the rafter system.

Butt. The upper part of the rafter leg must be cut at an angle equal to the slope of the roof. The opposite leg is also adjusted to the appropriate angle, but tilted in the other direction. Next, they are connected to each other at the top point using a nail, which must be driven into the end of the rafters, gripping the opposite end. In addition to nails, special plates are used to connect joints more firmly. Such fasteners can act as wooden plank 30 mm, and a metal fixing double-sided pad. Bolts or nails are used to install it.

The next two methods will be similar to the first, but have a slight difference. When fastening with an overlap, the upper parts of the rafter legs will be connected to each other by their sides. Last option carried out by connecting each rafter directly to the ridge beam. In this case, threaded rods with washers and bolts are used as fasteners.

If trusses are used to stiffen the rafter system, then to ensure good resistance to wind loads it will be necessary to install required amount diagonal ligaments. The presence of a brace and strut (rafter leg) in the supporting structure helps the gables of the house to be more stable. Installation of the brace is carried out by resting the upper part against the corner of the pediment, and the lower part rests against the main floor beam. The brace helps reduce the load on the rafters in the center. Its installation is carried out at an angle of 45º. Diagonal connections are secured using clamps, angles, and plates.

Types and features of metal fasteners for rafters

If previously craftsmen used such fasteners wooden elements(bars, pads, dowels, metal staples, wooden pins, wedges), now such methods are inferior to more modern species. The construction market has a large the lineup metal fasteners, which are now much stronger and make the process of installing the rafter system much easier. The manufacturing technology of these elements uses metal, the thickness of which varies from 1.5...3.0 mm, which allows the product to be more resistant to loads compared to any other material. In addition, rafter fasteners are available in any size and allow you to carry out the technological process with great precision.

Types of fastening elements for rafters.

Metal rafter fasteners, which can be perforated or nailed, include:

perforated mounting tape;
corners;
plates;
beam support;
beam support;
wire tie;
self-tapping screws;
bolts with nuts;
corners of the Kyrgyz Republic;
WB brackets;
LK fasteners.

The use of perforated products makes it possible to securely secure the rafters with all parts of the system and ensure good rigidity and strength at any angle. They are characterized by the presence of many holes for bolts, screws and self-tapping screws, with the help of which fastening to wood is carried out. The size of the product is adjusted by trimming to desired length and width.

Also, fasteners can be nailed. However, the use of this type is possible only in factory conditions using the cutting method, which bends the cone-shaped part. This operation is carried out by special machines under pressure.

KR angles have a large number of modified types, which reduce the risk of breakage of the bolted connection during natural settlement of the structure. Fastening is carried out without the use of special equipment using screws and nails.

WB brackets are used to fasten the support beam console when installing wooden floors in houses made of rounded logs or timber. In this case, no insertion is made on the rafter leg, which does not weaken its load-bearing capacity. The connection is made using anchor bolts, nails or screws.

LK rafter fasteners are applicable in sub-rafter systems where it is necessary to connect rafters and beams. It has the same advantages as WB fasteners, but the process is carried out only with screws or nails. Used in the construction of wooden houses.

Fasteners in the rafter system play a huge role. The strength and service life of the entire roofing pie depends on it. Therefore, the choice of type and method of fastening should be treated with great attention.

Fasteners for rafters: strength and reliability of the roof

In order for the roof to have high strength, special attention Requires fasteners for rafters. The type of connection will depend on the shape of the roof and the type of rafter system.

Attaching rafters to the Mauerlat: connection methods

Rafters are the main load-bearing structural elements roofs. Correct and reliable fastening of the rafters to the mauerlat eliminates the risk of deformation and collapse of the roof under its own weight and external loads.

Basic fasteners

To install the rafter legs on the Mauerlat and secure them firmly, use different kinds notch (inset) and metal rafter fasteners:

wire ties;
corners;
plates;
WB brackets;
KR corner;
LK fasteners;
self-tapping screws;
nails;
perforated mounting TM;
bolts, studs complete with nuts and washers.

The connection of rafters and mauerlat can be made using brackets. In this case, no tie-in is made into the rafters, thus this key structural element is not weakened. Mounting brackets are made of 0.2 mm thick steel with anti-corrosion zinc coating. The brackets are attached to the wooden beam and rafters with self-tapping screws, nails or anchor bolts.

LK fasteners allow you to attach the rafter to the mauerlat, as well as connect other elements of the system. When installing this fastener, anchor bolts are not used.

The use of perforated mounting tape allows you to strengthen the connection unit. The perforated tape makes the connection of the rafters with the Mauerlat stronger and does not weaken the supporting structures, since it does not violate their integrity. Installation requires screws or nails.

The KR corner and its modifications are widely in demand fastener rafter system. It is used when it is necessary to securely install rafter legs on the mauerlat. The corner adds strength to the joints, increases load-bearing characteristics design, eliminates the displacement of rafters under high operating loads. The corner does not need to be cut into the wooden elements of the rafter system; it is mounted with self-tapping screws or rough nails (equipped with special protrusions).

Metal fasteners for the rafter system must be made of quality material with reliable anti-corrosion protection - this guarantees its strength and durability.

In what cases is a Mauerlat required?

Mauerlat is often called the roof foundation. This structure, made of logs or timber, allows not only to securely fasten the rafters, but also to ensure uniform load transfer to the walls and foundation of the structure.

When building houses from timber or logs, the role of support for the rafters is performed by the upper frame of the walls; installation of additional structures is not required.

For buildings whose walls are made of piece materials(brick, foam concrete or aerated concrete blocks, etc.), installation of a Mauerlat is necessary. This is due to the fact that walls of this type do not cope well with point, undistributed loads. In addition, blocks made of foam material are not strong enough to securely fix the rafter system - fasteners can be torn out of the block under load. Thus, installation of a Mauerlat is required.

To wooden beam, laid on the longitudinal walls of the building or along the entire perimeter (depending on the type of roof) was firmly attached to the base, it is recommended to first create a reinforced concrete belt in the upper part of the walls. Fasteners for the support beam are embedded into a monolithic beam with a height of 200 mm and a width that matches the width of the wall. These are anchor bolts or studs with a diameter of 14 mm, located strictly vertically. To eliminate the possibility of them being pulled out of the concrete under high loads, the lower ends of the studs or bolts should be bent. The embedded fasteners are located in increments of no more than 1.5 m.

The use of studs with a diameter of less than 14 mm can lead to deformation of the fastener under loads.

In the timber from which the Mauerlat is mounted, holes should be made corresponding to the location of the studs. The beam is put on the studs, washers are put on the free threaded end of the fastener and nuts are screwed on. This technology allows you to securely fasten the roof base to the wall.

Before installing the timber, it is necessary to lay a waterproofing layer to prevent damage to the wood under the influence of moisture.

Principles of attaching rafters to the Mauerlat

Installation of rafters on a support beam may be required when creating spacer and non-spacer rafter structures. Installation of layered or hanging rafters on the Mauerlat is performed using a rigid or sliding connection. Depending on the design features, methods of attaching the rafters to the Mauerlat are selected.

A rigid connection implies the complete exclusion of displacement of elements relative to each other, the absence of influences such as shear, torsion, and bending. The necessary rigidity of the connection is ensured if the rafters are attached to the mauerlat with corners with a support bar, or a special “saddle” cutout is made in the rafter leg. The location of the cutout in the rafter is additionally secured with self-tapping screws, nails, staples, and bolts. In addition, it is necessary to perform a wire twist that connects the rafter attachment point with the Mauerlat and the anchor mounted in the wall.

When constructing roofs of wooden houses, a special fastening element (“sled”) is used, which allows for a sliding connection. The attachment point of the rafters to the mauerlat with a certain degree of freedom of the rafters makes it possible to avoid deformation of the roof during the shrinkage of a house made of timber or logs.

Installation of rafters using a corner

When choosing how to attach the rafters to the Mauerlat, you must proceed from the design features of the roof. If we're talking about not about wooden buildings, then the joint must be rigid.

If the installation of the rafters is carried out with a “saddle” cut out, then the work technology is as follows:

a cutout is made in the rafter leg in such a way that the horizontal part of the rafter can be installed on a wooden beam, and the angle of inclination of the rafter leg must correspond to the angle of inclination of the slope;
the rafter is fixed with three nails, two of which are driven in on both sides of the rafter leg at an angle (crossing should occur inside the Mauerlat), and the third nail is driven in vertically from above;
Additionally, the fastening unit is fixed with staples and rolled wire.

This fastening of the rafters to the Mauerlat provides the necessary rigidity and strength of the assembly.

A fairly common technology is the installation of rafters using a metal corner and hemming beams. The rafters are attached as follows:

the rafter leg is cut at the required angle to ensure the slope of the roof slope specified by the project;
a hemming beam is mounted along the edge of the mauerlat, the length of which is about 1 meter, the rafter rests rigidly against it along the pressure line - this design eliminates the shift of the rafter leg under thrust loads;
on the sides, the rafters should be fastened to the mauerlat using metal corners - fastening the rafters to the mauerlat with these elements makes it possible to avoid transverse displacement of the rafter leg;
the finished fastening unit is additionally reinforced with wire rod.

Attaching the rafters to the mauerlat should be carried out following the instructions; details of the work technology can be found in the video.

The rafters are attached to the wooden support beam using special corners. Subspecies of the corner of the Kyrgyz Republic include:

models KR11 and 21 (improved KR1 and KR2) are equipped with oval holes for anchoring, which can significantly reduce the risk of breakage of the fastening element when the building settles or the structure is loaded;
model KP5 allows you to fasten structural elements with high load-bearing capacity;
model KR 6 (reinforced corner) is made of 3 mm steel, has an oval hole for anchoring, and is used for installation of heavy structures.

Load-bearing and auxiliary elements of wooden truss structure are also fastened using a KM mounting angle made of perforated steel. Its advantages include the possibility of fastening with self-tapping screws and screws, without the need to use special equipment for installation.

Reinforced angle KMRP is used for connections at 90° angles. Its use allows you to securely install wooden rafters on the support beam. The angle can be adjusted.

Correct fixation of the rafter legs on the Mauerlat is the key to the durability and reliability of the roofing structure. The scheme for attaching the rafters to the mauerlat may be different, but there are general installation rules:

it is important to ensure a tight fit of the planes of the wooden elements, which requires careful and precise execution of cuts and notches;
using bolted connections It is necessary to install washers or metal plates to avoid the nut from sinking into the wood - this can lead to destruction of the fastening unit.

The use of pads is prohibited, as over time they deform, which leads to improper distribution of loads on the roof and entails deterioration performance characteristics, destruction.

Fastening rafters to the Mauerlat: how to fasten, fastening point, methods

Find out how to attach rafters to the Mauerlat. Types and methods of connecting rafters, a diagram of the fastening units of the Mauerlat and rafters along with a video.

How to choose the right fasteners for installing a rafter system

The frame of the rafter system and the foundation of any roof is the Mauerlat. In wooden houses, its functions can be performed by the upper crown of the frame, and in brick and concrete walls A powerful timber base is installed.

Mounting the Mauerlat

1. In houses made of laminated veneer lumber or logs, a Mauerlat is not required. If the height of the load-bearing walls is not enough, an additional crown-mauerlat is laid. For its fastening, forged brackets and steel dowels (spikes) are used.

2. Mounting the Mauerlat on brick walls possible in several ways:

– in the process of laying load-bearing walls, studs with a diameter of at least 14 mm are walled up to a depth of 3 or more upper rows of bricks. The lower end of the pin should be bent at a right angle in the shape of the letter “L”. The length of the free part of the pin should be 3-4 cm greater than the thickness of the Mauerlat;

- on final stage load-bearing wall masonry is poured reinforced belt. “L”-shaped studs or anchor bolts with a diameter of at least 14 mm are embedded into it. The length of the open part of the fastening elements should be 3-4 cm greater than the thickness of the Mauerlat.

The distance between the studs (anchor bolts) is selected as a multiple of the rafter pitch and is equal to 1.0. 1.5 m.

Before installing the Mauerlat, a layer of waterproofing material must be laid on the stone walls.

Fastening the rafters

1. Houses made of logs or timber shrink during use, and their geometric parameters change. In such conditions, the roof must have some independence. When rigidly fastening the rafter system, the roof wooden house warps, and roofing materials are destroyed. In the worst case, this can lead to destruction of the house frame, so the rafter connections are made movable.

Rafters in the ridge can be attached in two ways:

– movable connection using an M16 bolt;

– connection using a plate hinge. In this case, on each rafter with 4 M10 bolts. M12 are attached with two steel plates. The role of the hinge is performed by an M16 bolt.

The rafters are fastened to the mauerlat using so-called “sleds”. The bracket and bracket are fastened with nails, while the rafter has the ability to move slightly relative to the Mauerlat along its longitudinal axis.

2. If the house is made of brick or cinder block, rigid fastening of the rafters is used. In this case, the ridge connection is made in the following ways:

– fixed butt joint. In this case, the rafters are fastened with nails, and the entire assembly is reinforced with an additional steel or wooden cover - a crossbar. The crossbar is attached to the rafters with M10 bolts. M12 or nails respectively;

– a fixed connection with a half-tree insert. In this case, the rafters are connected with an M16 bolt, and the assembly is reinforced with a crossbar.

The rafters are fastened to the mauerlat using reinforced steel corners. M10 bolts are used to fasten the corners. M12 and nails.

Clamps, wire ties and mounting perforated tape are used as additional fastenings for fixed units.

All threaded connections are performed using metal washers or plates.

When fastening structural parts with nails, you must adhere to the following rule: the length of the nail should be 2-3 times the thickness of the element being pierced.

How to choose the right fasteners for installing a rafter system

For novice craftsmen who are building a house with their own hands, the rafter system is perhaps the most complex design. Mounting methods raise the most questions individual elements and the fasteners used. The stability and durability of the roof largely depend on these components, so we will talk about them in more detail.

Attaching the rafters to the mauerlat

The reliability of the roof structure directly depends on how correctly its entire supporting system is installed. And its main elements are rafters. The whole system consists of rafter legs that support and expand additional elements, such as struts, crossbars, side purlins, support posts and braces. The rafter legs are connected on a ridge beam from above, and their lower edges very often rest on a mauerlat mounted on the side load-bearing walls of the building.

Attaching the rafters to the mauerlat

Since the Mauerlat bears the heaviest load, it is made of powerful timber. Its cross-section is determined by the massiveness of the entire rafter system, but generally the size ranges from 150 × 150 to 200 × 200 mm. This load-bearing element is designed to evenly distribute the load from the entire roof and roof structure onto the load-bearing walls of the building. The rafters are attached to the mauerlat in various ways. They are selected locally depending on the type of rafter system (which can be layered or suspended), its complexity and massiveness, and the magnitude of the total loads to which the entire roof structure will be subjected.

Types of connecting nodes “rafters - Mauerlat”

First of all, there are sliding and rigid fastenings of rafters to the Mauerlat.

1. Sliding mounts consist of two separate elements, one of which has the ability to move relative to the other.

These fasteners can be of different designs - closed and removable.

Closed sliding mount

A closed mount consists of an angle, which is attached on one side to the Mauerlat, and on the other side has a special slot-like eye. It installs metal loop with holes for fastening to the rafters. Thanks to the free, unfastened vertical side of the corner, the fastening allows the rafters to move somewhat if necessary, without exerting a deforming effect on the walls of the building.

Open type movable sliding mount

The open fastening is designed according to the same principle, and differs only in that the metal loop is not inserted into the eye, but simply the upper part of the vertical shelf of the angle bends down after installation, thereby fixing the connection.

Video: example of installing a movable mount on a rafter leg and mauerlat

2. Types of hard There are many more fastenings. They are selected depending on the massiveness of the wooden structural elements and the method of installing the rafters on the mauerlat.

Various rigid mounts

This includes metal corners different sizes, LK fasteners, which will securely fix the rafter installed using a saw, without damaging it with fastening screws or nails.

LK fasteners are produced in several sizes, so they can be selected to suit any thickness of bar or board. The thickness of the metal from which these fasteners are made is 2 mm, no matter what size they are. Depending on the size, fasteners have different designations.

It should be noted that these fasteners are suitable not only for connecting rafters to the mauerlat - they are also used for fixing the “floor beam - mauerlat” assemblies.

LK fastenings in action

The main advantage of this fastener- this is maximum rigidity and reliability of the connection of wooden elements.

Fastening rafters with a cut to the Mauerlat using corners is carried out on both sides, which ensures the required rigidity.

Angle with reinforced bending rib

There are corners designed for fastening rafters without cuts. They have higher shelves and are screwed on with a large number of screws. They are made from metal 2 thick; 2.5 or 3 mm.

Fastening the rafters to the mauerlat with corners

KR 11 and KR21 are improved corners, often marked as K R1 and KR2. These elements have an oval-shaped anchor hole, which reduces the risk of bolt breakage in the event of shrinkage of the structure.

Corners series KR

KR5 and KR6 are angles used for fastening elements that bear a large load-bearing load. The corner to K P6 is also equipped with an oval hole, and it is recommended to use it when creating a rafter system on a new house, which will still shrink. These models are in demand when installing structures that have a lot of weight.

Angle to K M is made of perforated steel and is used for fastening rafters with a large cross-section. It is especially suitable for wooden buildings. This corner secures the structural elements very reliably, and when using it, there is no need to insert the rafters into the mauerlat - it is enough to cut out the correct angle first.

Reinforced corner KMRP series

The KMRP corner is used to fasten parts of the rafter system at right angles, including the rafters with the Mauerlat. It also differs from conventional angles in its elongated hole, which allows displacement during shrinkage without damaging the mounting bolt. It can be used in structures where it is impossible to insert one element into another.

KMRP corners are produced from steel 2 mm thick. Three varieties are available:

Another option for fastening the rafters to the mauerlat is to install them between two boards, sawn at a certain angle, and additionally fixed at the bottom using metal corners or LK fasteners.

Fastening the rafters between two planks

This fastening of the rafters provides good rigidity and reliability. This method is well suited in cases where the rafter needs to be secured at the desired angle, lifting it above the horizontal plane of the Mauerlat, but securing it to the vertical outer side.

The method of attaching rafters to a mauerlat made of timber is not very large section. This is done by strengthening the beam with wooden pads of the required thickness.

Fastening using reinforcing lining

Sections of boards are attached to the mauerlat using nails or self-tapping screws in the places where the rafter legs will be installed.

In this case, cuts are made in the rafters required configuration and depth. The rafter legs are securely fixed to the wall using steel wire, which is secured to a driven steel spike.

Fixation with wire twist

In addition to the above-described fastening methods, the rafters are nailed to the Mauerlat using staples. It should be noted that this method is quite common and has been used for a very long time. If these elements are properly secured, the rafter system will last for many years.

Fastening “the old fashioned way” - with brackets

The staples can be of different sizes and are driven in at different joints.

Another fastening element that is used as an auxiliary element is TM perforated tape. It is used to strengthen the fastening unit if additional fixation is necessary.

Metal perforated tape often comes to the rescue

In some cases, this element may be irreplaceable, so it also cannot be excluded when installing rafter legs on the mauerlat.

Features of rafter systems

The rafter system is selected depending on the location of the load-bearing walls of the building. Each of the systems has its own additional supporting or tightening elements.

Types of rafter systems

Layered rafters

A system with layered rafters is distinguished by the fact that it has one or more support points, in addition to load-bearing walls. In this regard, a significant part of the load is removed from the side walls.

Layered rafters supported by a solid partition

In the form of additional supporting elements, side posts and “headstocks” are used, supporting the ridge and secured to the floor beams. And the beams themselves, in turn, simultaneously serve as tension for the structure, and also lighten the load from the rafter system on the load-bearing walls.

Rafters with sliding fastenings

Layered rafters are attached to the Mauerlat most often with sliding joints, which can move when the walls shrink or deform, leaving the roof structure intact. This is especially important to take into account in new buildings, since any newly built building necessarily shrinks under the influence of temperature fluctuations and ground movements.

Hanging rafters

The rafters are called hanging due to the fact that they have no other supports besides the two side load-bearing walls. It turns out that they seem to hang over the internal space of the building. In this case, the entire load from the roof frame structure falls on the Mauerlat.

Rafters in a hanging type system

To attach hanging rafters to the mauerlat, rigid fastenings are used with no degree of freedom of movement, since frame construction has only two points of support.

To remove part of the load from the walls of the building, additional elements are used, such as struts, headstocks and bolts, which pull the system to the ridge beam and evenly distribute the load on all walls. The crossbars are installed parallel to the floor beams and tighten the rafters together. Without these additional parts, the design may become unreliable.

Calculation of rafter installation

In order for the rafter system to be reliable and durable, in addition to the optimal connection method, you need to choose the correct spacing of the rafter legs. This parameter is selected depending on the size of the rafters (their cross-section and length between support points), as well as on the roof structure.

In this table you can obtain information about the necessary parameters for installing a reliable rafter system.

Several rules for attaching rafters to the Mauerlat

In order for the fastenings to be reliable, it is necessary to follow a number of rules that are provided for this process:

If metal connecting parts are used for fastening, then they must be fastened to the wooden connecting elements with maximum care - with high-quality self-tapping screws of the required length.
If the rafters are to be laid in grooves in the mauerlat, then the dimensions must be precisely adjusted. This will ensure tight reliable installation rafters into the prepared cut, which should have a depth of ⅓ of the mauerlat. However, it should be remembered that such a rule will only be valid if the power plate is made of a powerful block with a cross-sectional size of at least 150 × 150 mm.

Gaps on the Mauerlat

In order not to weaken the Mauerlat, most often cuts are made in the rafter leg itself at the desired angle, and additionally the knot is then fixed with corners. In this case, the cut should not exceed ¼ of the thickness of the rafters. This fastening is rigid and can be used in a hanging rafter system.

In this embodiment, the cut is made on the rafter leg

When using bolts to fasten rafters with slopes, tie-rods and other wooden elements, it is necessary to install a washer or metal plate on the bolt to avoid the nut from sinking into the wood and, accordingly, weakening the structure.
Fastening rafters to the mauerlat only with nails or self-tapping screws is considered unreliable, so it is necessary to use corners or other metal fasteners of various configurations.

Wide selection of metal fasteners

When installing rafters on wooden walls, whether it is a hanging or layered system, it is recommended to attach them to the Mauerlat with a sliding fastening, especially if the roofing material is quite heavy.

Attaching rafters to the mauerlat - how to do it correctly?

One of the most important connecting units in a roof structure is the attachment of the rafters to the mauerlat. There are several approaches to solving this problem.

The reliability of the roof structure directly depends on how correctly its entire supporting system is installed. And its main elements are rafters. The entire system consists of rafter legs that support and expand additional elements, such as struts, crossbars, side girders, support posts and braces. The rafter legs are connected on a ridge beam from above, and their lower edges very often rest on a beam fixed to the side load-bearing walls of the building.

Types of connecting nodes “rafters - Mauerlat"

First of all, there are sliding and rigid fastenings of rafters to the Mauerlat.

1. Sliding mounts consist of two separate elements, one of which has the ability to move relative to the other.

These fasteners can be of different designs - closed and removable.

A closed mount consists of an angle, which is attached on one side to the Mauerlat, and on the other side has a special slot-like eye. A metal loop with holes for fastening to the rafters is installed in it. Thanks to the free, unfastened vertical side of the corner, the fastening allows the rafters to move slightly if necessary, without having a deforming effect on the walls of the building.

The open fastening is designed according to the same principle, and differs only in that the metal loop is not inserted into the eye, but simply the upper part of the vertical shelf of the angle bends down after installation, thereby fixing the connection.

Video: example of installing a movable mount on a rafter leg and mauerlat

2. There are many more types of rigid fastenings. They are selected depending on the massiveness of the wooden structural elements and the method of installation on the Mauerlat.

This includes metal corners of different sizes, LK fasteners that will securely fix the rafter, installable by sawing it down without damaging it with fastening screws or nails.

LK fasteners are produced in several sizes, so they can be selected to suit any thickness of bar or board. The thickness of the metal from which these fasteners are made is 2 mm, no matter what size they are. Depending on the size, fasteners have different designations.

Designation	Size in mm
LK-1L	40×170
LK-2P	40×170
LK-3L	40×210
LK-4P	40×210
LK-5L	40×250
LK-6P	40×250

It should be noted that these fasteners are suitable not only for connecting rafters to the mauerlat - they are also used for fixing the “floor beam - mauerlat” assemblies.

The main advantage of this fastener is the maximum rigidity and reliability of the connection of wooden elements.

Fastening rafters with a cut to the Mauerlat using corners is carried out on both sides, which ensures the required rigidity.

There are corners designed for fastening rafters without cuts. They have higher shelves and are screwed on with a large number of screws. They are made from metal 2 thick; 2.5 or 3 mm.

Designation	Size (length height width, metal thickness) in mm	Designation	Size (length height width, metal thickness) in mm
Reinforced corner	105 × 105 × 90 × 2	Reinforced corner KP5	140 × 140 × 65 × 2.5
Reinforced corner	130 × 130 × 100 × 2	Reinforced corner KP6	105 × 172 × 90 × 3.0
Reinforced corner	105 × 105 × 90 × 2	Reinforced corner KP7	145 × 145 × 90 × 2.5
Reinforced corner	50 × 50 × 35 × 2	Reinforced corner KP8	145 × 70 × 90 × 2.5
Reinforced corner	70 × 70 × 55 × 2	Reinforced corner KPL1	90 × 90 × 65 × 2
Reinforced corner	90 × 90 × 40 × 2	Reinforced corner KPL11	90 × 90 × 65 × 2
Reinforced corner KP1	90 × 90 × 65 × 2.5	Reinforced corner KPL2	105 × 105 × 90 × 2
Reinforced corner KP11	90 × 90 × 65 × 2.5	Reinforced corner KPL21	105 × 105 × 90 × 2
Reinforced corner KP2	105 × 105 × 90 × 2.5	Reinforced corner KPL3	90 × 50 × 55 × 2
Reinforced corner KP21	105 × 105 × 90 × 2.5	Reinforced corner KPL4	70 × 70 × 55 × 2
Reinforced corner KP3	90 × 50 × 55 × 2.5	Reinforced corner KPL5	50 × 50 × 35 × 2
Reinforced corner KP4	70 × 70 × 55 × 2.5	Reinforced corner KPL6	60 × 60 × 45 × 2

A few additional words need to be said about some of the corners shown in the table, since their description requires clarification:

— KR 11 and KR21 are improved corners, often marked as TO P1 and KP2. These elements have an oval-shaped hole for anchoring, which reduces the risk of bolt breakage in the event of shrinkage of the structure.

— KR5 and KR6 are angles used for fastening elements that bear a large load-bearing load. Corner TO P6 is also equipped with an oval hole, and it is recommended to use it when creating a rafter system on a new house, which will still shrink. These models are in demand when installing structures that have a lot of weight.

— Corner TO M is made of perforated steel and is used for fastening rafters with a large cross-section. It is especially suitable for wooden buildings. This corner secures the structural elements very reliably, and when using it, it is not necessary to insert the rafters into the mauerlat - it is enough to cut out the correct angle first.

— The KMRP corner is used to fasten the parts of the rafter system at right angles, including the rafters with the Mauerlat. It also differs from conventional angles in its elongated hole, which allows displacement during shrinkage without damaging the mounting bolt. It can be used in structures where it is impossible to insert one element into another.

KMRP corners are produced from steel 2 mm thick. Three varieties are available:

Angle designation	Dimensions in mm
	a	b	c
KMRP1	60	60	60
KMRP2	80	80	80
KMRP3	100	100	100

Another option for fastening the rafters to the mauerlat is to install them between two boards, sawn at a certain angle, and additionally fixed at the bottom using metal corners or LK fasteners.

This fastening gives good rigidity and reliability. This method is well suited in cases where the rafter needs to be secured at the desired angle, lifting it above the horizontal plane of the Mauerlat, but securing it to the vertical outer side.

A method of attaching rafters to a mauerlat made from timber of not too large a cross-section. This is done by strengthening the beam with wooden pads of the required thickness.

Fastening using a reinforcing lining

Sections of boards are attached to the mauerlat using nails or self-tapping screws in the places where the rafter legs will be installed.

In this case, cuts of the required configuration and depth are made in the rafters. The rafter legs are securely fixed to the wall using steel wire, which is secured to a driven steel spike.

In addition to the above-described fastening methods, the rafters are nailed to the Mauerlat using staples. It should be noted that this method is quite common and has been used for a very long time. If these elements are properly secured, the rafter system will last for many years.

Fastening “the old fashioned way” - with staples

The staples can be of different sizes and are driven in at different joints.

Another fastening element that is used as an auxiliary element is perforated tape TM. It is used to strengthen the fastening unit if additional fixation is necessary.

In some cases, this element may be irreplaceable, so it also cannot be excluded when installing rafter legs on the mauerlat.

Features of rafter systems

It is selected depending on the location of the load-bearing walls of the building. Each of the systems has its own additional supporting or tightening elements.

Layered rafters

A system with layered rafters is distinguished by the fact that it has one or more support points, in addition to load-bearing walls. Due with this, with side walls, a significant part of the load is removed.

In the form of additional supporting elements, side posts and “headstocks” are used, supporting and secured to the floor beams. And the beams themselves, in turn, simultaneously serve as tension for the structure, and also lighten the load from the rafter system on the load-bearing walls.

Hanging rafters

To attach hanging rafters to the Mauerlat, rigid fastenings are used with no degree of freedom of movement, since the frame structure has only two points of support.

The hanging rafter system is braced and therefore puts a lot of pressure on the walls.

Calculation of rafter installation

In order for the rafter system to be reliable and durable, in addition to the optimal connection method, you need to choose the correct spacing of the rafter legs. This parameter is selected depending on the size of the rafters (them and the length between the support points), as well as on the roof structure.

In this table you can obtain information about the necessary parameters for installing a reliable rafter system.

Installation pitch of rafter legs in mm	Length of rafter legs in mm
	3000	3500	4000	4500	5000	5500	6000
600	40×150	40×175	50×150	50×150	50×175	50×200	50×200
900	50×150	50×175	50×200	75×175	75×175	75×200	75×200
1100	75×125	75×150	75×175	75×175	75×200	75×200	100×200
1400	75×150	75×175	75×200	75×200	75×200	100×200	100×200
1750	100×150	75×200	75×200	100×200	100×200	100×250	100×250
2150	100×150	100×175	100×200	100×200	100×250	100×250	-

Use it in the article on our portal.

Prices for various types of fasteners for rafters

Rafter fasteners

Several rules for attaching rafters to the Mauerlat

In order for the fastenings to be reliable, it is necessary to follow a number of rules that are provided for this process:

If metal connecting parts are used for fastening, then they must be fastened to the wooden connecting elements with maximum care - with high-quality self-tapping screws of the required length.
If the rafters are to be laid in grooves in the mauerlat, then the dimensions must be precisely adjusted. This will ensure a tight, reliable installation of the rafters into the prepared cut, which should have a depth of ⅓ of the Mauerlat. However, it should be remembered that such a rule will only be valid if the power plate is made of a powerful block with a cross-sectional size of at least 150 × 150 mm.

In order not to weaken the Mauerlat, most often cuts are made in the rafter leg itself at the desired angle, and additionally the knot is then fixed with corners. In this case, the cut should not exceed ¼ of the thickness of the rafters. This fastening is rigid and can be used in a hanging rafter system.

When using bolts to fasten rafters with slopes, tie-rods and other wooden elements, it is necessary to install a washer or metal plate on the bolt to avoid the nut from sinking into the wood and, accordingly, weakening the structure.
Fastening rafters to the mauerlat only with nails or self-tapping screws is considered unreliable, so it is necessary to use corners or other metal fasteners of various configurations.

When installing rafters on wooden walls, whether hanging or layered, it is recommended to fasten them to the Mauerlat using a sliding fastening, especially if the roofing material is quite heavy.

Video: several examples of attaching rafters to the Mauerlat

The roof structure will be strong and will last a long time, without being deformed by a variety of external influences, if the calculations of all elements are made correctly, and all fastening units are correctly selected and installed correctly.

The rafter structure is the skeleton of the roof, which must take on and evenly distribute the weight of the roofing materials. If you correctly assemble the wooden frame under the insulation, waterproofing film and finishing coating, you will be able to achieve a noticeable increase in the load-carrying capacity of the rafter system.

Main elements of the rafter system

The wooden roof frame is assembled from the following parts:

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 pie;
The Mauerlat serves as the basis for the roof frame
rafter legs are irreplaceable parts of the wooden skeleton of the roof, determining the angle of inclination of the slopes and the appearance of the upper part of the house;
ridge girder - a beam fixed in a horizontal position and, like a spine, connecting all the rafters of the roof frame in their upper part;
The ridge girder is located exactly in the middle of the building
side purlin - a horizontal beam, which differs from the ridge purlin in that it is fixed in the middle of the rafters of each roof slope;
tightening - a spacer that unites two opposite rafters so that they do not move apart;
Tightening and struts are necessary for proper distribution of the load on the Mauerlat
racks - vertical frame elements placed under the ridge and side purlins to support the rafters and ridge beams, and also, if necessary, placed under the middle part of the rafter legs;
Racks can support not only the roof ridge, but also the rafters
struts - parts that rest against the leg, due to which the rafter legs become more stable;
bench - a beam placed 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;
The bench is located on the inner wall parallel to the mauerlat beam
roof ridge - the area where two slopes combine, along which a continuous sheathing is installed, which is necessary to strengthen the described part of the roof;
The ridge is formed in the highest zone of the rafter system
fillies - elements used in arranging an overhang when the rafter legs are not long enough;
The fillies lengthen the rafter legs
roof overhang - zone wooden frame, protecting the walls of the house from contact with large amounts of precipitation;
The 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 perpendicular to the rafters

Main connecting nodes

The main components of the rafter system are:

roof truss - connection rafter pair, stretch marks, as well as racks and braces;
ridge knot - combination of two opposite rafters;
a link made of a mauerlat and a rafter resting on it;
a module including a run, a stand and a bench;
connection of the rafters with the strut and the stand.

The most complex element of the roof frame, according to the author, is the roof truss, which is distinguished by the fact that:

The ridge knot also has several features:

The rafters and mauerlat become a single link, which is characterized by the following:

A module of purlins, racks and beams is formed by driving construction brackets, steel dowels or overlays made of steel strips into the places of their connections.

An assembly of a beam, a rack and a purlin allows you to divide the load between the external and internal walls of the building

Struts, racks and rafters are assembled into a single module, creating cuttings. To prevent their connection from being weak, construction staples are used.

An assembly of struts, posts and rafters allows you to soften the pressure on the internal wall of the house

Methods of fastening rafters

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

Connection with Mauerlat

Rigid fastening of the rafters to the Mauerlat ensures that there are no displacements of the assembly elements. It is performed by cutting in a certain sequence:

To speed up the work, make a template from a piece of board or thick cardboard. A line is drawn on the workpiece, departing from the side edge at a distance equal to 1/3 of the rafter width, and then the point of contact with the mauerlat beam is marked, along which a second line is drawn, perpendicular to the first.
If the rafter width is more than 200 mm, then the cut is made at a depth of 70 mm
At the angle of inclination of the roof slope, the template is placed against the edge of the Mauerlat, making sure that the point marked on the piece of wood is strictly opposite the corner of the beam. 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 manufactured template is assessed for correctness by placing it on the Mauerlat in several places. If the groove made turns out to be smaller or larger than needed, then the pattern is made again, correcting the mistake.
The template is placed on a horizontal rafter. The triangle in the pattern is outlined with a pencil. The same is done 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 in the rafters every time. Otherwise, the notches will be created at different distances from the ridge.
The triangles drawn on the rafters are cut out hand hacksaw. Use the tool slowly, so as not to accidentally increase the depth of the groove in the rafter leg. If you have the skills to work with an electric saw, you can make notches with this device. However, one must keep in mind that an instrument powered by electricity is much less responsive to the hand and is capable of moving to the side.
A triangular cut allows the rafters to rest against the mauerlat
The correct size of the grooves made is checked with a template. If inconsistencies are found, the notch is corrected with a hacksaw.
The two outer rafter legs are placed at the top of the house. They are inserted into the Mauerlat using grooves, secured on 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 after another.

Builders without experience can take note of the technology of attaching rafter legs to the mauerlat with a stripe of a thrust block. With this method of creating a node, 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 to the Mauerlat with a stripe of a thrust bar, do the following:

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

Choice sliding rafters justified only when a ridge beam is provided for the main elements of the roof frame, into which they could rest with their upper part.

When the rafters are fixed to the mauerlat using the sliding method, certain steps are taken:

The layered method of attaching rafters to the mauerlat is adopted when the purchased lumber turns out to be shorter than necessary. Also, this method of fixing the main elements of the rafter system is used during the repair of a roof of complex configuration.

When fixing the rafters to the mauerlat using the layered method, only 3 tasks are performed:

Video: installing rafters

Alignment with floor beams

You can attach rafters to the floor beams only if you are 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 point-like. Without fear or doubt, the rafters are attached to the floor beams if they are building a light mansard roof . At the same time, as ceiling beams

use boards with a section of 5x15 cm.

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

To firmly secure the rafter legs to the floor beams, perform the following tasks:

Wall mount

If for some reason the rafters have to be fixed directly to the walls, then they will definitely need to be connected with a tie. As the author of the article, who helped build the roof of the utility room, was personally convinced, it will relieve some of the stress transmitted by the rafter legs from the house. Under no circumstances should rafters be directly connected to external walls

buildings, if they are built from foam or gas blocks. These materials easily transfer their moisture to the wood and are unable to retain fasteners.

The rafters can be fixed to the wall using a sliding method, but this is not the most reasonable solution

To securely fix the rafter legs to the walls, it is necessary to take certain measures:
Make a notch with one tooth on the rafters at the desired angle.
Place the rafters on the walls with their ends and drive a nail 10–12 cm long into them.

Since the ridge of the roof experiences serious pressure from the entire rafter system, roofers with extensive experience create a ridge assembly in five ways: end-to-end, on a beam, overlapping, in a groove, in half a tree.

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

When attaching 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 pointed, but flat.

If you make a ridge knot by fastening the rafters together with an overlap, you will need to perform several simple tasks:

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

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

Video: construction of a roof frame with a ridge girder connecting the rafters

The construction of the rafter system should not be started until it is possible to understand the features of attaching the rafters to other elements of the supporting structure of the roof. By the way, among in various ways There are options for fixing rafter legs not only for experienced builders.

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 yourself, you need to know how to properly make the fastening points of the rafter system so that the roof is reliable and safe.

Construction of the rafter system

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

Mauerlats are responsible for distributing loads on the walls. These beams take the weight of the entire roof and lie on the walls.
Rafter legs- These are inclined beams that create the required angle of inclination of the roof.
Purlins are horizontal beams that hold the legs together. There is a ridge girder located at the top, and side girders located on the slopes.
The puffs are located horizontally and do not allow the rafter legs to move apart, forming rigid triangles with them.
Racks and struts(rafter legs) - additional elements on which the rafter legs rest. They rest against the beds.
The beam is a horizontal beam located under the ridge; the posts and struts rest on it. The purpose of the bench is to redistribute the point load from the racks.
The ridge is the junction of the roof slopes.
Lathing - bars or boards that are placed perpendicular to the rafters. Roofing material is laid on it. The purpose of the sheathing is to distribute its weight.
An overhang is an elongated edge of a slope that protects walls from precipitation. If the length of the rafter legs is not enough to create an overhang, additional elements are used - fillies.

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

Also in the roof structure there are roof trusses. This is a continuous assembly consisting of rafter legs, braces, racks and struts (braces, jibs). The truss can be not only triangular, but also trapezoidal, segmental or polygonal. Which type of truss to choose depends on the size of the house. If the distance between the walls is 9-18 m, then a triangular truss is suitable. For houses with a width of 12 to 24 m, trapezoidal or segment trusses are used. If the building width is larger (up to 36 m), then polygonal trusses are used.

The main fastening points for the roof truss system are beam, ridge and mauerlat.

Types of rafter systems

Rafters can be hanging or layered.

Hanging ones rest on the walls and create space. To reduce it, ties are made at the base of the rafters, which connect the rafters and form triangles with them. Hanging systems various types 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 no more than 9 m, then the rafters are supported by a vertical beam - the so-called headstock. It is located under the ridge.

If the width of the house is from 9 to 13 m, additional struts are installed, which rest against the rafters at one end and against the headstock at the other.

For a house width of 13-17 m, two vertical racks, connected at the top by a crossbar (fitting), as in the figure.

Layered rafters rest on a load-bearing wall or columns inside the building. With this method, the rafter has three or more support points. The layered type of rafter system creates less load 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 interior walls, they can be symmetrical or asymmetrical.

How the parts of the rafter system are connected

To connect wooden elements together, nails, bolts, studs are used, as well as metal plates and angles to strengthen the nodes. Additionally apply wooden blocks or plates.

Fastening methods:

teeth into a spike,
teeth point blank,
emphasis at the end of the crossbar.

The use of metal fasteners does not reduce the load-bearing capacity, since their insertion is not required, unlike fastening, for example, using the tooth-to-tenon method.

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

Attaching to the 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 can be attached to the mauerlat in two ways: rigid and sliding.

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

Each rafter is nailed with three nails: two of them should be crossed, and the third should be located vertically.
Fastening with a bracket: one end of it is driven approximately into the middle of the support beam, and the other is turned 90 degrees and driven into the rafter.
Fastening with wire rod: a clamp is made from wire folded in 4 rows, with which the rafter is screwed to the beam. 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 the hard method is that when the building settles, 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 by such fastening elements that do not impede their movement within certain limits. This method is used in wooden buildings that can settle. Using 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 means that the rafter can rotate in a circle. In this case, they are secured with one nail or screw. The two degrees of freedom are circular rotation and horizontal displacement. To do this, the rafters are attached to the mauerlat with metal brackets. Special corner sleds are also used.

With a sliding connection 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 notch on the rafter leg.

Important! The notch 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 emphasis on the beam) or movable (with a tooth on the outside). Sometimes, instead of cutting out a tooth, an additional block is used.

Ridge connection

After the rafter leg is secured to the Mauerlat, they move on to the ridge attachment point. This connection can be made in three ways: end-to-end, to the ridge girder and overlapping.

For end-to-end fastening, the rafters are cut at the top 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 wooden plate is attached, which is also nailed or attached with bolts.

When attached to a ridge girder, a ridge beam (purlin) is additionally laid between the rafters; this method is more labor-intensive.

When fastening with overlap, the rafters located on opposite sides overlap each other and touch their side 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, so various techniques are used.

It is necessary to cut out a tooth and a tenon in the heel of the rafter, and cut out a stop of the appropriate size in the beam.
The attachment point should be 25-40 cm from the hanging edge of the beam.
The mounting socket should be 1/4 - 1/3 deep of the beam thickness.
Together with the tooth, a spike is cut out, which prevents the rafter from moving to the side. This connection is called a “tooth with tenon and stop”.

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

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

All wooden elements are treated with an antiseptic and fire-resistant compound before installation.
The thickness of any wooden part should not be less than 5 cm.
Rafters without posts and struts are not made longer than 4.5 m.
The Mauerlat must be positioned strictly horizontally.
It is recommended to make the racks and struts as symmetrical 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 and 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 take on the entire weight of the roofing materials and resist wind loads. Therefore, it is very important to build a rafter system in compliance with technology.