Attaching the truss to the Mauerlat. Knots of the rafter system: how to fasten correctly. Types of metal plates

The rafter system is the frame of the entire roof. It is this structure that takes on all the loads and is the basis for the roofing. But for this system to work properly and reliably, the rafters must be secured correctly. This work can be done in various ways. Much will depend on the location where the rafter legs are attached, as well as on the type of system itself. So how to complete the task correctly? What options for fastening rafters are there? This is what we will talk about.

We attach it to the Mauerlat

The rafter system is a rather complex structure. It includes many elements. That is why it is very important to correctly attach each part to the right place. When constructing the frame of the future roof along the entire perimeter of the walls of the house. This element must evenly distribute all loads. This is where the lower part of the rafters is most often fastened. An exception can only be if the role of the mauerlat is played by the top beam of a wooden house. But in this case, the fasteners are made in the same way.

So how to do it? What options do professional builders offer? There are several methods of fastening, namely:

The first fastening option is called rigid. This connection is considered the most reliable. But at the same time you will have to spend more effort and time. The essence of this fastening of rafters is as follows. A gash is made in the leg. Its geometry should repeat the shape of the Mauerlat. The depth of the cut should not be more than one third of the width of the rafters. To make your work easier, you can make a template. It is done along the first rafter. Then, using the template, you can file the rest. But this option can only be used if the power plate is flat and lies strictly horizontally. Otherwise, each fastener will need to be adjusted individually.
You can also secure the rafters using a stop block. This method is quite simple, so it is recommended for beginners. In this case, the rafters are fastened to the mauerlat using two bars. They are boards with a thickness of at least 40 millimeters. They need to be secured on both sides of each rafter. This is best done with nails. Next, the thrust bars are attached to the Mauerlat itself. With this method of fastening the rafters, it is easy to adjust both the angle of the slope and the length of the overhangs.
Another option for performing this type of work is to use the sliding method. It is worth fastening in this way if the house is made of wood. This material shrinks. To prevent the rafter system from “falling apart,” all connection points must be movable. In order to fasten using the sliding method, you need to purchase special fasteners. This design consists of two parts. One is mounted on the rafters, the other on the mauerlat. The result is a movable mount, read also:.

These are the main types of connection between rafters and Mauerlat. Quite often they are combined. For example, if you need to cover a log house with a roof (the walls are made of logs), then the sliding method is used. But for greater strength, the rafters are cut in an arc. This method is more labor-intensive and not every “newbie” can do it.

Video on the topic:

We attach to the ridge purlin and to each other

The rafters must be fastened not only at the bottom, but also at the top. Much will depend on the type of system itself. If the layered version is used, then the rafters will be attached from above to the ridge beam or purlin. In the case of application, things are a little different. In this case, the rafters need to be fastened to each other.

How to properly attach the rafters at the top? What methods can be used here? Experts will answer these questions as follows:

Video on the topic:

There are other options for similar fastening. For example, some experts recommend using the tongue-and-groove system. But this method requires serious carpentry skills. Therefore, it is not used so often.

How to stitch

If the house is small in width, then there will be no special problems with finding material for construction. But if the structure is large, then an operation such as fastening rafters from several parts or building up may be necessary. How can you cope with such a task? Here builders advise fastening the parts together in one of the following ways:

Diagonal or main rafters cannot always be made from a solid board or timber. In this situation, you cannot do without merging the two parts. But when doing this work, you need to remember the basic rule. Such a connection must be strong, because it will be influenced by strong loads. Therefore, fastening must be done efficiently and slowly.

What is used at work

How to attach the rafters to the Mauerlat or to each other was discussed a little higher. There are many options to make this work. But to ensure a strong connection, the correct fastening devices must be used. Of course, first of all we are talking about nails. It is with their help that rafters and other elements of the system are most often secured. But there are other devices.

When constructing the roof of a house, the following elements can be used:

special mounting perforated tape;
metal corners;
steel plates;
beam and beam support;
nail plates;
wire tie;
bolts with nuts;
staples;
corners of the Kyrgyz Republic;
WB brackets;
LK fasteners and so on.

Fasteners for the rafter system are available in a wide range. Each of them has its own application features, pros and cons. Quite often, metal corners and plates are used for reliable fastening. Such fasteners for rafters allow you to securely hold them in place. For a skate, a corner is most often used.

Plates for fastening rafters can be either simple steel strips or have a nail type. The latter option does not require additional fastening (nails or screws are not used here). On the back side of the plate there are already thin and sharp protrusions, with the help of which it is mounted. But there is one subtlety here. A nail plate can only be used if the rafter pair is assembled on a horizontal surface, and only then installed in its place.

Another fastening element is very often used - staples. They are a metal rod bent at both ends at right angles. Using staples, you can strengthen the places where the rafters are attached to the mauerlat or to the ridge beam.

KR corners are produced in a large assortment. Their main goal is to prevent the bolted connection from loosening. WB brackets are used to attach rafters to wall beams. In this case, there is no need to make cuttings. Therefore, their use greatly simplifies and speeds up work.

Fastening the rafters to the ridge girder, mauerlat or to each other is an important task. To do this work correctly, you should use the following recommendations from experts:

It doesn’t matter what material the walls of the house are made of, you always need to make a Mauerlat. Foam block, brick or something else, all this will not give the desired horizontalness. As a result, fastening the rafters will be more difficult. In addition, the Mauerlat will allow you to evenly distribute the load on the walls. The only exception can be a house that is made of beams or logs. But even here it will be difficult to do without a Mauerlat if the topmost row is not laid strictly horizontally.
If the rafter legs are sewn from two parts, then the connection must be strengthened. In this case, struts or racks are installed under it. In this case, to attach additional supports, you can use plates of various types.
If the rafter system does not use a ridge purlin (suspended structure), then the upper connection point of the truss should be strengthened. In this case, in addition to the usual fastening of the rafters to each other, metal corners or plates are used.
The installation of a hip roof frame can cause particular difficulties. Here, in addition to the main rafters, diagonal and rafters are used. It is with their fastening that difficulties may arise. The upper end of the diagonal rafters is attached to the end of the ridge girder and to the main rafter. In this case, the cutting method is used. On the diagonal rafter itself, cuttings should be made or special bars should be filled. The nazhniki will attach themselves to them.
If you rigidly attach the rafters to the Mauerlat using a template, then you need to be careful. First of all, you must make sure that both horizontal and vertical positions are maintained. The Mauerlat should lie flat. Having made the template, do not rush to make cuts on the remaining rafters. You should go through all the attachment points. This is necessary to check if the template fits perfectly.
When doing installation, first install two outer trusses on both sides of the house. Then a rope is pulled between them. It will serve as a guide so that the remaining rafter pairs are fastened at the same level.
If the method with thrust bars is used, then there is no need to make additional elements to prevent it from tipping over. But only if the fastening is made on both sides of the rafters. In all other options, additional devices are required to prevent tipping over.
The sliding mount may not always be used. Since there will be no reliable support from below, a ridge run must be required. Therefore, this method of attaching rafters to the Mauerlat is used only with a layered system.
Another nuance concerns the sliding method. If one is used, then the rafters should be attached to the top using a hinge joint. It can be used to relieve vertical loads.
When choosing a place where the rafters will be attached, you should avoid problem areas. These are mainly bitches. The area around them is quite fragile. If you attach the rafters here, the connection will be unreliable. If a place prone to rot is found on the site, then such a wooden element should absolutely not be used.

The rafter system is the frame of the roof of the house, which carries and evenly distributes the weight of the roofing pie, sometimes reaching up to 500 kg/m2. The reliability of this unique frame depends on three factors: the accuracy of the calculation, on the basis of which the number and cross-section of the supporting elements are selected, the material from which it is made, as well as the correctness of the fastening technology. Knowing how to properly fasten rafters, you can significantly increase the load-bearing capacity of the frame, making it stronger and more reliable. Installation errors, on the contrary, lead to significant losses in strength and deformation of the roof. In this article we will talk about the main types and methods of fastenings with which you can qualitatively install rafters with your own hands.

The rafter frame of the roof of a house is a system of interconnected supporting elements made of wood or metal that 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:

Layered. Layered rafters are called supporting elements that have two points of support in the roof structure - 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 rafters can be “leaned.” This fastening of the rafters allows you to relieve them through the use of additional vertical supports.
Hanging. Hanging elements are those that have only one support point, located where the rafters are attached to the wall or mauerlat. A hanging type rafter system experiences load not only in bending, but also in expansion, so it is strengthened by horizontal compensating elements (crossbars, tie rods, tie rods).

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 cross-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 softens the pressure on the walls of the house and also evenly distributes the weight of the roofing pie. You can attach the Mauerlat to the upper chord of the walls using anchor bolts or embedded metal studs.

Main connecting nodes

The rafter frame is called a system because all 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 point that can easily deform under load, so all fastenings must be carried out strictly according to technology. Experienced craftsmen identify the types of connections in the roof structure:

Attaching the rafters to the ridge beam. This connecting unit is typical only for layered rafter systems, in which the upper part of the rafter leg rests on a ridge girder mounted on vertical posts. The rafters can be attached to it using metal plates, nails or sliding slide fasteners.
Fastening the rafters to the mauerlat. The most important fastening point of the rafter frame is considered to be the junction of the mauerlat beam with the rafter legs. You can fix the rafters on it using nails, metal corners or wooden blocks.
Connecting the rafters to each other. To lengthen the rafter legs, if the length of the slope exceeds the standard length of lumber, they are assembled from several elements connected to each other using nails, glue or metal plates.
Connection of rafter legs with auxiliary supporting elements. In truss frame construction, rafters can be connected to tie rods, transoms, or struts to increase rigidity, strength, and load-bearing capacity.

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

Fixation methods

When deciding how to attach rafters to a mauerlat or ridge girder, you need to choose the right fastening hardware. The modern construction market has a huge range of fasteners of various designs and sizes. The main criteria for choosing fasteners are the material used to make the rafters, their cross-section, as well as the type of load to which they are subjected. There are the following methods of fastening rafters:

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

Types of fastenings

Wood is a natural material that, in the process of equalizing humidity and drying, causes significant shrinkage, which is why 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 the active to the passive phase. If you fix the wooden frame elements rigidly, then after drying the roof of the house may become deformed. Therefore, the following types of fastenings are used to connect 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 high strength and rigidity of the structure.

Types of fasteners

There is ongoing debate among experienced roofers as to what is the most effective way to attach rafters to floor beams and mauerlat. However, in most cases the problem is that in these conditions it is more practical to use nails or self-tapping screws. Both of these fasteners have their own advantages and disadvantages:

Nails are good because all you need to hammer them in is a hammer, which is available in every household. However, some craftsmen complain that hammering them in by hand takes too long. It is worth recalling that special jagged nails are used to fix the rafters, which securely adhere to the wood.
To assemble the rafter frame, galvanized self-tapping screws are used, which are not afraid of corrosion. Due to the thread, they are firmly screwed into the thickness of the wood, securely fixing the elements together. Screwing them in quickly and conveniently with a portable screwdriver. The disadvantage of this type of fastener is that during dismantling, removing screws from wood is long and tedious.

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

Video instruction

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 for 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 - a zone of a wooden frame that protects 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:

rafter truss - a connection between a pair of rafters, braces, as well as posts and braces;
ridge knot - combination of two opposite rafters;
a link made of a mauerlat and a rafter resting on it;
a module that includes 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, during 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.

Connection with Mauerlat

Rigid fastening of the rafters to the Mauerlat ensures that there is no displacement 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 on 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 saw. 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 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 it, it is possible to avoid deformation of the rafter structure and deterioration in the stability of the top 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, 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. In this case, boards with a section of 5x15 cm are used as ceiling beams.

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.

In no case should rafters be directly connected to the external walls of the building 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.
If necessary, attach metal corners to the sides of the rafters.

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 the various methods of fixing rafter legs, there are options not only for experienced builders.

Attaching the rafters to the mauerlat is one of the most important moments in the construction of a house, in particular when installing the roof.

The entire complex roof system rests on the Mauerlat, which is its basis, the so-called foundation of the entire roof.

It is the Mauerlat that protects load-bearing walls from distortions associated with roof pressure, while equally distributing the load along the entire length of the walls.

The rafters, in turn, are the main structural parts of the roof.

The main components for connecting rafters to the Mauerlat

To begin with, it is worth highlighting the main mounting elements for installing the roofing system.

These include:

corners - used when necessary to firmly install the rafter legs on the mauerlat. Capable of making the fastening more durable. The advantage is that there is no need to make cuts in the wooden parts - the corners are secured with ruff nails or self-tapping screws;
brackets are made of galvanized steel. Installation is carried out without cutting down the wood; the brackets are secured with anchors, nails or screws;
perforated mounting tape - used for additional fixation of the connection unit, giving the roofing system tenacity. Installation requires screws or nails;
LK fasteners, “sleds” - used to protect the roof from deformation during soil subsidence and shrinkage of the building;
bolts with nuts, nails, wire ties, self-tapping screws, and some other elements.

All connecting parts must be of high quality and reliable - you should not skimp on this.

It is necessary to exclude the use of all kinds of gaskets, which over time can become deformed and fall out.

The rafter structure consists of a mauerlat, valleys, rafter legs, ridge partitions, purlins, and sheathing.

To understand how all the components are connected to each other, you need to determine what the coupling nodes of the Mauerlat and rafters are.

To begin with, the Mauerlat is attached to the axis of the wall. There are few fastening methods.

The first method is suitable when installing a large roof area. To do this, an armored belt is poured around the entire perimeter of the wall, into which metal pins are immediately inserted.

In this case, the Mauerlat will be attached to the wall with studs that pass through the beam and are mounted.

When using the second method, the Mauerlat is attached to the wall using wire. To do this, you need to lay it between layers of bricks (3-4 rows before the end of the masonry).

In this case, you can fix the rafter with wire directly to the wall. However, this kind of connection can compromise the integrity of the wall.

If the knot is attached to a beam, then a “tooth with a tenon” is prepared in the rafters, and a stop for the tenon must be cut out in the beam with this socket.

The notch is made at a distance of 0.2 - 0.5 m, starting from the part of the beam that hangs down. A single “tooth” is made with a spike that will prevent it from moving to the sides.

In the case of a flat roof, if the degree of inclination is less than 30°, then the rafter legs are mounted with increased support on the beam.

There are three types of ridge connection: end-to-end, overlapping, and attached to a ridge beam.

In the first case, one part of the rafters must be cut at the same degree as the slope of the roof, and then it must be rested against the corresponding rafter on the reverse side (they must be cut equally).

It is advisable to cut corners using a stencil. For fixation, 2–4 nails are usually used. The joint is secured by placing a plate of wood or metal on it.

Installation on a ridge beam is similar to the previous mount. The difference is that a ridge beam is fixed between the rafters cut at an angle. This type of knot is complex, for this reason it is practically not used in construction.

Overlapping is the most popular method, although it is similar to the first. The main difference is that the connection is made not end-to-end, but overlapping. The rafters are connected by side cuts. Attract them with nails, bolts or studs.

Schemes and methods of attaching rafters to the Mauerlat

Fastening the rafters is one of the most important moments in roof construction. The condition of the roof under different circumstances (snowfalls, showers, temperature fluctuations) will depend on the method of fastening the support beams.

Rigid fastening scheme

For single-pitched and gable roofs, a rigid installation scheme of the rafter system to the base is used.

The system of this fastening eliminates the possibility of affecting the connections of the nodes. During the operation of the roof, possible shifts and deformations of the roofing system are minimized.

High strength is based on the use of metal corners. Additionally, it is recommended to fix the beam to the base on both sides with special corners - this will help prevent lateral displacements.

The installation of the rafter system is carried out at the desired angle, and it is necessary to set a certain slope for the structure, fixing it with side nails. When using a rigid design, anchors and wire are often used.

Sliding mounting option

Everyone knows that wood expands when there is high humidity, and contracts during hot and dry weather.

For this reason, in the construction of wooden houses, not a rigid, but a sliding scheme is often used.

When using this fixation scheme, in certain cases, the nodes of the truss structure may shift in the desired direction. The gable roof design is suitable for using this fastener.

There are several types of fastening for this scheme. So, you need to make a recess on the rafter leg, then fasten the Mauerlat and the beam, then secure everything with nails.

Moreover, this must be done in such a way that the nail passes right through the beam and sits firmly in the base.

Another type of fixation can be done using metal staples and special plates. An element called “sled” is very often used.

Despite the fact that the scheme is called sliding, all structural elements are securely fastened together, but if necessary, they are evenly shifted.

The use of this fastening scheme is due to the fact that over time the soil shifts and the foundation sags - this leads to damage to the roof frame.

The sliding scheme helps to avoid unnecessary changes and destruction of the roof structure.

How to attach rafters to the mauerlat? It depends on the location of the load-bearing walls. Methods of attaching rafters to the mauerlat are divided into layered and hanging. Layered, in turn, are divided into spacer and non-spacer.

Layered method of fastening rafters

The use of a non-thrust device for rafter legs makes the pressure on the load-bearing walls less. On a pre-fixed tightening there are vertical posts, which will be the support points. This method is suitable for single-pitch and gable roofs that have a main load-bearing wall.

The support unit of the rafters to the mauerlat is often made hinged (sliding). If you use movable hinges in the connections, the roof structure can be lowered by several centimeters.

This property is very useful in the first years after construction, since over time the new building settles.

If, together with the supporting walls, the roof does not change its position, then the walls of the building may be subject to deformation or destruction. This will not happen if the rafters are attached in a layered manner.

When using rafter fasteners of the spacer system, rigid fasteners must be used without the use of hinges.

In this design, all connections are made thanks to the support bar. It turns out that the top of the attached rafter rests on the top of the corresponding rafter on the other side.

How to properly fasten the rafters in this case? Fastening to the required Mauerlat must be carried out to the wall.

For this purpose, a rigid frame is suitable, fixed to the wall with anchors or brackets, in the corners of which special corners must be installed.

This design is suitable if you need to install a roof for small houses. For large buildings, the Mauerlats are installed in special concrete gutters and fastened with anchors. The main load in such a system falls on the gutter and is used in the construction of cinder block buildings.

Hanging mounting scheme

Hanging rafters are intended for use in the construction of buildings without load-bearing walls inside. The support points in this case are only the external load-bearing walls.

The fastening of this design is carried out by a rigid type unit. Other options are not suitable, since the connection of rafters with a mauerlat on the walls is the only support for the entire pitched or gable roof.

Rafters installed in a hanging manner place a strong horizontal load on the walls.

To reduce pressure, puffs (crossbars) are used. They are installed at the base of the structure perpendicular to the rafters. Attached to all the beams, the crossbars hold the rafters together.

You cannot build a roof with hanging rafters without using tie-downs.

A few important nuances

you need to use only high-quality materials. There is no point in saving on this, since the durability of the roof and the safety of the residents of the house directly depend on the reliability of the structure. Negligence during roof installation is fraught with all sorts of displacements or, even worse, collapse of the entire structure;
all work should be carried out extremely carefully; the use of different gaskets is unacceptable;
It is not recommended to use the installation of rafters without a Mauerlat, as there may be a risk of distortion and damage to the integrity of the walls of the house;
the most suitable method is the sliding fixation method, which will avoid deformation of the rafter system in the event of soil subsidence.

The arrangement of the roof of the house should be approached very seriously - you should not rush when attaching the rafters to the mauerlat.

Before starting construction work, the truss structure must have a clear design; all places of connecting nodes must be immediately identified.

A sufficient supply of all mounting elements of proper quality is required. With this approach, you can be confident in the reliability and durability of the roof.

The rafter system is the basis for the entire roofing structure. The safety of the roof directly depends on how well this system is designed and how firmly its component elements are connected to each other. No less important is the correct choice of building materials: both wood for the rafters themselves and fastening fittings. So, what constructive solution to choose for organizing the rafter system so that the roof can successfully cope with the effects of winds and the weight of snow cover in winter? How to fasten rafters so that there is no risk of premature deformation or destruction of the roof? We will talk about the main points regarding the installation of rafters below.

Basic terms

1. Rafters- these are beams made of logs or beams that are the support for the roofing “pie”, which includes both the finishing roofing covering and the hydro- and vapor barrier layers. The lower part of the rafters - the rafter legs - can rest either on the wall of the building itself or on the mauerlat. The upper parts of the rafters are connected to each other end-to-end or overlapped at an angle, and then attached to the ridge beam or purlin. The main types of rafters are:

Layered, which are suitable for roofs with intermediate columnar supports. The lower part of such rafters (leg) rests on the mauerlat, the middle part on an intermediate wall or support, the upper part on the ridge. Thus, the rafters experience less stress.

Hanging ones, which do not have additional support, which means they work both in bending and compression, and also create a significant bursting force. To strengthen the structure, a tie is used - a horizontal beam that is attached to the rafter legs and at the same time can serve as a floor beam.

2. Mauerlat is a massive beam, usually a beam with a cross-section of at least 15x15 cm, which is laid on the axial walls parallel to the ridge. The Mauerlat is fastened to the wall using studs recessed into a reinforced concrete belt. The Mauerlat is placed on the protruding parts of the studs, and then the fastening is reinforced with nuts. The Mauerlat is necessary so that the load from the roof structure is evenly distributed along the entire length of the axial walls, and does not represent separate points. In light structures, for example, houses made of timber or log cabins, it is allowed rafter fastening directly onto the top crown or beam of the wall, without erecting a mauerlat. Capital buildings made of brick and concrete blocks must have a Mauerlat.

The most comprehensive information about rafters can be obtained from Wikipedia.

Overview of fastening fittings for rafter installation

There are several types of fastening elements for arranging a rafter system. All of them are united by the material of manufacture – metal. The most popular types of fasteners are:

Corners that are used to strengthen nodes during installation of rafters. Corners not only make the fastening more durable, but also increase the load-bearing capacity of the structure. Another advantage is that there is no need to make recesses in the wood, that is, the integrity of the elements of the rafter system is not compromised. Corners fasten nails with ruff-type protrusions on the stem or screws.

Perforated tape, which also serves to give the rafter structure strength and additional rigidity.

Brackets, which are made of 2 mm galvanized metal and are attached to the wood with anchor bolts, screws or nails.

LK fasteners, similar in design to brackets and fixed with nails or screws.

“Sled” fasteners used for mounting the truss system of wooden houses in order to protect the roof structure from deformation during the shrinkage of the building.

Perforated metal plates.

Other types of fastenings that are used when arranging the rafter system are bolts with nuts, self-tapping screws, and wire ties.

The main types of connections found when arranging a rafter system

The approach to how to fasten rafters, is determined depending on the location of the attachment point:

rafters and mauerlat;
two bars when increasing the length of the rafters;
rafters and additional structural elements that strengthen the roofing system.

Scheme of rigid fastening of rafters to the Mauerlat

Rigid fastening of rafters is used when it is necessary to create a strong connection between the rafter base and the Mauerlat. An important requirement: the fastening should not be affected by factors such as torque, sliding, turning, etc. an effort.

The strength of the structure is ensured by:

equipping the rafter leg with a gash - the so-called “saddle”;
equipping the fastening unit with a stripe in the form of a support bar.

How fix the rafters correctly to the Mauerlat in this way? First, using a template, a recess (“saddle”) is created on the rafter leg in order to further place the rafter on the mauerlat. It is prohibited to make any cuts on the Mauerlat, because violating the integrity of this element can significantly reduce the load-bearing capacity of the entire rafter system!

After the rafter leg and the mauerlat are joined, the elements are fastened using three nails: two are driven into the sides of the rafters at an angle to the rafters and to each other, and the third is strictly vertical in the middle. A more reliable method of fastening is metal corners, which are fixed with nails with special protrusions on the leg.

The knot will be made even stronger by the supporting block, which is mounted under the rafter leg and rests against the mauerlat.

Photo of fastening the rafters to the Mauerlat Attaching the rafters to the mauerlat photo of attaching the rafters to the Mauerlat photo of attaching the rafters to the Mauerlat photo of attaching the rafters to the Mauerlat photo of attaching the rafters to the Mauerlat photo of attaching the rafters to the Mauerlat photo of attaching the rafters to the Mauerlat photo of attaching the rafters to the Mauerlat

Sliding rafter technology

Those who are interested in how to fasten rafters when arranging the roof of a house made of timber or rounded logs will want to know about sliding fastening. A rigid connection between the mauerlat and rafters is not suitable in this case, because wooden houses necessarily shrink in the first few years after construction. If the roof is not given some room to move in the direction of expansion/contraction, it may become deformed or even collapse.

With this method of fastening, the mauerlat and rafters are connected using special “sled” fittings or corners with elongated holes for nails.

Photo of the sliding fastening of the rafters to the Mauerlat

Video about the sliding method of fastening and its installation:

Installation of rafters on beams (when arranging a roof without a Mauerlat)

If you are planning to install a simple roof for a wooden house, the rafters can be attached to the floor beams. However, keep in mind that the distribution of the load from the roof will be point-wise and not distributed, as with a Mauerlat. With this constructive solution, the floor beams should protrude beyond the contour of the walls by about 40 cm. To ensure that all rafters are fixed at the same angle to the beams, a string is pulled across the latter, which will serve as a guide for cutting out grooves for installing rafter legs.

To make the fastening unit more durable, cuts are made both at the base of the rafter leg and in the floor beam. In the first case it is a “tooth with a spike”, in the second it is a socket for a spike. To avoid reducing the load-bearing capacity of the beam, the nest should have a depth of no more than 1/3-1/4 of its width.

Fastening the rafters in the upper (ridge) part

At this stage, you can act according to one of three schemes:

fasten the upper parts of the rafters, cut at the required angle (ideally according to a template), end-to-end using long nails, or even better, metal plates;

fasten the rafters with an overlap using a bolt and nut, studs or nails. This method is considered more reliable than the first because the rafters have a larger contact area;

fasten the rafters end-to-end and secure them to the ridge purlin. This scheme differs from the first method in that there is also a ridge beam. In this case, the “saddle” is made not only on the rafter leg, but also on the upper part, which will rest on the ridge girder. If the ridge is large, it may require additional supports, which is completely unsuitable for attics that will be used as living quarters.

Extension of rafters

As a rule, standard lumber has a length of up to 6 m. If the slope of your roof is longer, it is necessary to build up, or lengthen the rafters. Here, too, you can act differently:

using the method of oblique cutting (at an angle of 45°) and connecting parts of the rafters with a bolt with a diameter of at least 12 mm;

end-to-end, strengthening the connection with overlay beams fixed with nails in a checkerboard pattern;

overlapping, observing the intersection of rafter sections of at least 1 meter in length and the arrangement of fastening fittings in a checkerboard pattern.

Several axioms regarding fastening rafters

How fasten rafters, each builder chooses himself, based on the design features of the roof, the building as a whole, as well as the climatic conditions of the region (wind strength, snowiness in winter, etc.). However, there are several rules that must be followed in any case:

Use high-quality mounting hardware. If you want your roof to be durable and safe, you shouldn't skimp.

The most reliable types of fastening are metal corners, plates, bolted and stud connections. Nails and screws are accessories for temporary fastening of rafters.

When building a wooden house, be sure to use a sliding connection between the rafters and the mauerlat or wall to avoid deformation of the roof during the shrinkage of the building in the first few years of operation.

Make cuts on the rafters carefully so that in the future you do not have to use liners or cut out extra centimeters/millimeters already in place. The ideal option is to use a template. Please note that if the roof is complex, and rafters will be attached to the Mauerlat at different angles; each type of location will require its own template. For all cases, the rule applies: the depth of the cut should be 1/3-1/4 of the width of the rafter leg.

If you choose bolts with nuts as fastening hardware, be sure to use washers and other sealants that prevent the bolt head from “sinking” into the wood.

Thus, the arrangement of the rafter system of a house should be approached extremely carefully and responsibly. There should be no place for haste here. Before the actual installation work begins, the rafter system must be designed, and the locations of all fastening units must be determined. You should always have a sufficient number of good quality fasteners at your disposal. Only with this approach can we guarantee the strength and reliability of the roof, the absence of deformations and serious damage during the operation of the house. Build wisely and with soul, and you will definitely succeed!

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