home > Water supply > Mauerlat is it necessary to put on. Mauerlat for the roof: what is it and how to do it. What is the secret of the quality of the truss system: the three main rules of the master

Mauerlat is it necessary to put on. Mauerlat for the roof: what is it and how to do it. What is the secret of the quality of the truss system: the three main rules of the master

Proper and durable fastening of rafters during the construction of a house is one of the key points of the entire construction process. Therefore, it is important that all components of the system are accurately matched, installed in place and firmly fastened into a single structure. It is undesirable for the builder to proceed with the installation of rafter elements without a pre-drawn scheme and the calculation of the quantity and range of required materials and accessories.

The roof truss system is the frame and skeleton of the roof.

The structural basis of the system

Rafters, i.e., the supporting base of a pitched roof, are log or block beams on which the so-called roofing pie is laid. The composition of the latter includes a layer of vapor barrier, waterproofing material and the final roofing. The soles of the rafters, i.e. their lower part, are attached directly to the wall of the building or to the Mauerlat. At the top, the rafters are laid by building them up from separate parts in a straight line, or at the required angle, and attached to the roof purlin or its ridge.

Hanging rafters can experience deformation loads, including compression and bending, which creates a significant bursting force. This is due to the fact that the fastening is made without additional support. This is permissible for the walls of the house, the distance between which does not exceed 6.5 m. Otherwise, a horizontal beam is installed - a puff, designed to evenly distribute the load. Very often it is also used as the basis of the overlap.

Figure 1. Elements and connection of layered rafters.

Roof structure with intermediate piers, requires the installation of layered rafters. The rafter soles are fixed to the Mauerlat, and the top to the roof ridge. In the middle, such rafters rest on supporting pillars or intermediate walls. This significantly reduces deformation and overload and makes the truss system fastening strong and durable.

An important part of the supporting base of the roof is the Mauerlat. It is made of timber, with a minimum section of 15 x 15 cm. For log cabins, Mauerlat can be omitted, but capital buildings made of concrete and brick are not built without it. Mauerlat is installed parallel to the roof ridge on the walls along the length of the house. Why is it necessary to make a concrete reinforced base with vertical mortgage screws on the walls. Mauerlat is put on these screws and fastened with nuts. (Fig. 1: Rafter attachment patterns.)

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Accessories for rafters

The fasteners for the rafter system are metal. It consists of:

steel corner;
perforated tape for tightening system elements;
nails, staples, screws, bolts, hairpins, knitting wire;
metal plates;
mounting "sled" to prevent deformation during shrinkage of the structure.

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Connection methods

It is necessary to determine how to fix the rafters when designing attachment points. For example, they are attached to the Mauerlat in a rigid way.

For such an attachment, “saddles” are cut out on the soles of the rafters according to the template. With the help of them, the beams are mounted on the Mauerlat, which remains solid. The “saddle” and the Mauerlat are joined with nails: one is hammered vertically in the middle, and the other two are driven at a slight angle to the carrier beam. You can also use metal corners, for fixing which nails with special spikes on the leg are used. Another mounting option is a retaining beam, installed under the sole of the rafter with an emphasis.

Elastic fastening of rafters is used in buildings made of beams or logs, since structures made of them shrink significantly in the first years after the construction of the house. The lack of the required fastening play can lead to failure or collapse of the roof. For sliding fastening, a steel corner with elliptical nail holes or special fastening “sleds” is used.

For work on fixing the structure, the following tools are required:

roulette;
building level;
square;
hammer;
wrenches;
electric drill;
saw;
screwdriver;
pencil.

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Roof installation without mauerlat

If the rafters are fastened directly to the floor beams, a point distribution of the weight of the roof comes out. Therefore, the beams must be elongated and protrude 40 cm beyond the line of the walls. To maintain the same angle when fastening across the beams, it is necessary to pull the string. It will become a guide when cutting grooves under the soles of the rafters.

Fastening rafters with a beam is made in the following ways:

spiked tooth;
stubborn tooth;
emphasis on the end of the beam.

The required number of teeth (1 or 2) is determined by the angle of inclination of the sole of the rafters. Having inserted the rafter ends into the grooves, they are additionally fixed on the beams using a bolted connection or steel corners.

When fastening with a beam is carried out by cutting, a single tooth is enough. For this method of fastening, the following rules must be observed:

The connection of the beams with the truss system is carried out if an angle of 35 ° is formed between them.
A protrusion with a spike is made at the base of the sole of the rafter, and a corresponding nest is made in the carrier beam.
The depth of the socket should be less than 25 - 30% of the width of the sole.
To avoid chipping the end under the pressure of the rafter's leg, the cut is performed by retreating 25 - 40 cm from the cantilever end of the beam.
To prevent lateral displacement allow teeth with stops or spikes;

A hollow roof with an angle of inclination not reaching 35 ° requires a cut, carried out in the following ways:

In 2 spikes;
Point-blank without spikes or with 1 spike;
In a castle with 2 spikes.

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Fastening the ends to the roof ridge

The question of how to attach the rafters to the upper roof beam is solved using 1 of 3 schemes:

Directly with nails or plates, cutting off the upper parts of the rafters according to the template at the required angle.
For overlapping, long bolts, nails or studs are used.
Butt-mounting on a roof ridge requires sawing out a "saddle" at the sole, as well as at the top end to support the ridge beam.

Rafter extension.

To increase the length of the rafters to the size of the roof, you need:

Make an oblique cut and connect the segments with a bolt with a diameter of 10-12 mm or more;
Butt-join and secure with overlay bars, which are fixed with nails;
Connect with an overlap with a cutout of at least 1 m, placing fasteners on both sides.

On the structure of rafters, lathing and roofing material many forces are at work. The lingering snow presses with its whole mass, the wind tries to tear it off. To prevent the roof from “driving” at your house, there is a time-tested building technique - the Mauerlat device.

Mauerlat - what is it and is it always needed? Photo

Builders, like most professionals, have a lot of tricky words that often confuse ordinary people. Almost everyone knows what a "base" is. But what is a Mauerlat and why is it needed - to a few. So let's tell you a secret: Mauerlat- this is what the roof rests on, more precisely, its entire truss system. In fact, this is the foundation, the foundation of the roof, which combines all its elements into a single structure.

Mauerlat performs two functions:

Compensates for the bursting force from the rafters.
Holds the roof on the wall.

If there is snow on the roof, especially melted snow, then the force of gravity generated by it is weakened by the value of the sine roof pitch angle. In addition to reducing the perceived load, the slope also changes the direction of the force acting on it. It becomes not vertical, but directed slightly to the side, outward. This is the pushing force.

Its value can be so significant that if the wall is made of discrete material (brick, aerated concrete blocks, concrete panels), then a rafter tree fixed directly on it can destroy the masonry. The solution to the problem is to fix a long beam on the upper edge of the wall - Mauerlat. The roof truss system is attached to it. For reliability, the mauerlat is laid around the entire perimeter of the upper edge of the main wall, forming a solid frame.

The slope of the roof, in addition to reducing the pressing force, also reduces and roof windage. However, not enough to be absolutely sure that the roof will not be blown away by a gust of wind. To compensate for the tearing force, the Mauerlat must be firmly fixed to the wall.

Mauerlat is being done from the same material as the entire truss system. Therefore, it can be not only made of wood, but also of iron. The main condition is that the rafter should be (ideally) a single inseparable structure, in extreme cases - securely docked.

Mauerlat arranged as a separate structure only in houses whose main walls are made of brick, aerated concrete blocks, rubble stone, adobe and other "discrete" building material. In wooden houses, the Mauerlat can be the last crown, especially firmly fixed on the previous ones. There is no need to arrange such a special design in frame houses.

How to arrange?

For the Mauerlat device, beams must be used, the cross section of which is equal to thirds of the thickness of the main wall. Usually a bar with a section of 150 or 200 mm is suitable for this. You should not take it thicker, since this is an additional load on the wall, and it is quite difficult to lift bars of such a section to a great height.

If the Mauerlat beams are joined, then the length of each part should be as large as possible. To illustrate this, the following example can be given: the standard length of any lumber is 6 meters. If the wall on which the rafters will rest is 8 meters long, then for the Mauerlat you need to take two beams of 4 meters each. Using a six-meter beam and a two-meter saw-off would be a mistake.

Before strengthening the beam on the wall, it must protect from moisture. To do this, it is enough to wrap it with roofing material and fix it with a construction stapler (the height of the staple is at least 10 mm).

Mauerlat beam laid on the inside edge main wall or exactly along the center line. Otherwise, you will not be able to securely fasten it. At the junction with the cross beam, a half-tree is washed down, a hole is drilled and a dowel is clogged. The connection angle is fixed with a construction bracket. It must be hammered so that the hypotenuse of an isosceles right triangle is formed.

How to fix on the wall?

In order for the Mauerlat to hold securely, all fasteners must be placed in the thickness of the masonry of the main wall. The easiest way to strengthen in masonry is long soft steel wire staples. It wraps around the Mauerlat, twists tightly, and the rest is bent. Bolts fixed in the masonry are more reliable, but marking and drilling holes in the beam is a long and painstaking task.

It is possible with building brackets, if wooden inserts are installed in the masonry under it (saw-off bars). They must be installed so that the bracket is hammered into the end, otherwise there is a risk that the liner will burst.

Mauerlat can be made from three boards 150 mm wide and 50 mm thick. The first of them is fastened with an anchor screw, the next two are nailed on top with nails 150 mm long. This method is convenient because the boards are easier to lift to a height. In addition, the anchor bolt can be installed already in the finished masonry, for example, if the installation of the roof is already done by you personally or by another construction team, and the previous builders did not install fasteners.

In conclusion, I would like to say that Mauerlat- an important and necessary detail in the design of the house. It is not worth neglecting her device. There are only two unshakable rules: use as long solid beams as possible and securely fasten them to the wall masonry. Otherwise, you can be guided by a sense of proportion and common sense.

We have already talked about the hip roof in one of the previous articles on the site. There was described the design of the roof with the support of the rafters on the Mauerlat. After the publication of the article, I received many requests to show how to make a hip roof with rafters resting on floor beams, and also to answer the question of whether it is possible to make a hip roof with different slope angles.

Thus, I wanted to “kill two birds with one stone” with one example. Now we will consider the construction of a hip roof with rafters resting on floor beams and with different slope angles.

So, let's say we have a box of a house made of heat blocks (polyblocks) 8.4x10.8 meters.

STEP 1: Install the Mauerlat (see Fig. 1):

Picture 1

STEP 2: We install long floor beams with a section of 100x200 cm in increments of 0.6 meters (see Fig. 2). I will not dwell on the calculation of beams anymore.

Figure 2

The very first we put beams that run strictly in the middle of the house. We will navigate along them by installing a ridge beam. Then we put the rest with a certain step. For example, we have a step of 0.6 meters, but we see that 0.9 meters are left to the wall, and one more beam could fit, but it does not. We leave such a span especially for "removals". Its width should not be made less than 80-100 cm.

STEP 3: Installing takeaway. Their step is determined when calculating the rafters, about which a little later (see Fig. 3):

Figure 3

For now, we only put the extension corresponding to the length of the skate, which will be equal to 5 meters. The length of the ridge is greater than the difference between the length and width of the house, which is 2.4 meters. What does this lead to? This leads to the fact that the corner rafter will not be located at an angle of 45 ° in plan (in the top view), and the angle of inclination of the slopes and hips will be different. For slopes, the slope will be more gentle.

It is enough to fix the removal on the Mauerlat with nails. We attach them to a long floor beam, for example, like this (Fig. 4):

Figure 4

There is no need to make any cuts in this knot. Any washed down will weaken the floor beam. Here we use two LK-type metal rafters on the sides and one large nail (250 mm) driven through the beam into the end of the stem. We hammer the nail with the very last one, when the stem is already fastened to the Mauerlat.

STEP 4: We install the ridge beam (see Fig. 5):

Figure 5

All elements of this design, except for the struts, are made of timber 100x150 mm. Struts from a board 50x150 mm. The angle between them and the overlap is at least 45°. We see that under the extreme racks there are bars resting immediately on five floor beams. We do this to distribute the load. Also, to reduce the load on the floor beams and transfer part of it to the load-bearing partition, struts were installed.

We determine the installation height of the ridge beam and its length for our house ourselves, making a preliminary sketch on paper.

STEP 5: We manufacture and install rafters.

First of all, we make a template for the rafters of the slopes. To do this, we take a board of the desired section that is suitable in length, apply it, as shown in Figure 6, and make markings using a small level (blue lines):

Figure 6

The height of the bar, which we put on the takeaway for marking the lower gash, is equal to the depth of the upper gash. We made it 5 cm.

According to the template obtained, we make all the rafters of the slopes, based on the ridge beam, and fix them (see Fig. 7):

Figure 7

In such structures, where the rafters do not rest on long floor beams, but on short extensions, we always put small supports under the rafters above the Mauerlat, forming, as it were, a small triangle and unloading the attachment point of the extension to the beam (see Fig. 8):

Figure 8

It is not necessary to bring these supports further inside the roof, and even more so to put them at the junction of the removal with the beam. Most of the load from the roof is transmitted through them (this can be seen in the calculation program) and the floor beam may simply not withstand.

Now a little about the calculations. When choosing a section of rafters for a given roof, we calculate only one rafter - this is the rafter of the slope. It is the longest here and its angle of inclination is less than the angle of inclination of the hip rafters (explanation - we call a roof slope in the form of a trapezoid a slope, a hip - a roof slope in the form of a triangle) Example results in Figure 9:

Figure 9

Yes, I forgot to say. Who has already downloaded this calculation program from my website before December 1, 2013. There is no ʺSling.3ʺ tab. To download the updated version of the program, go to the article again at the link: http://stroyu-dom-sam.ru/stropilnaya-sistema/

This article has also been slightly corrected due to feedback from some readers, for which special thanks to them.

STEP 6: We add the takeaway and fasten the wind boards (see Fig. 10). We add enough offsets so that there is room for attaching the corner offset. Wind boards at the corners are just stitched together, controlling their straightness. Check visually for sagging corners. If so, put temporary props under them directly from the ground. After installing the corner offsets, these supports are removed.

Figure 10

STEP 7: We mark and set the corner offset.

To begin with, we need to pull the cord along the top of the floor beams, as shown in Fig. 11

Figure 11

Now we take a beam of a suitable length (the cross section is the same as for all extensions) and put it on top of the corner so that the lace is in the middle of it. From below on this bar with a pencil we mark the lines of cuts. (see fig. 12):

Figure 12

We remove the lace and install the timber sawn off along the marked lines (see Fig. 13):

Figure 13

We attach the corner offset to the Mauerlat with the help of two roofing corners. We fasten it to the floor beam with a 135 ° corner and a large nail (250-300 mm). Corner 135 °, if necessary, bend with a hammer.

Thus, we put all four corner offsets.

STEP 8: We manufacture and install corner rafters.

At the hip roof, which I described earlier, the angles of inclination of the slopes and hips were the same. Here, these angles are different and therefore the corner rafter will have its own characteristics. We also make it from two boards of the same section as the rafters. But we sew these boards together not quite usually. One will be slightly lower than the other (about 1 cm, depending on the difference in the angles of the slopes and hips).

So, first of all, we pull 3 laces on each side of the roof. Two along the corner rafters, one along the middle hip rafter (see Fig. 14):

We measure the angle between the lace and the angular offset - the bottom washed down. Let's call it "α" (see Fig. 15):

Figure 15

We also mark the point "B"

We calculate the angle of the upper gash β = 90°- α

In our example, α = 22° and β = 68°.

Now we take a small piece of board with a rafter section and saw down one end on it at an angle β. We apply the resulting blank to the ridge, combining one edge with the lace, as shown in Fig. 16:

Figure 16

On the workpiece, a line was drawn parallel to the side plane of the adjacent slope rafter. On it, we will make another gash and get a template for the upper gash of our corner rafter.

Also, when we apply the workpiece, it is necessary to mark point “A” on the rafter of the slope (see Fig. 17):

Figure 17

Now we make the first half of the corner rafter. To do this, take a board of suitable length. If one board is not enough, we sew two boards. You can temporarily sew it by trimming an inch long about a meter into self-tapping screws. We make the upper washed down according to the template. We measure the distance between points "A" and "B". We transfer it to the rafters and make the lower washed down at an angle "α".

We install the resulting rafter and fix it (see Fig. 18):

Figure 18

Most likely, due to its length, the first half of the corner rafter will sag. It is necessary to put a temporary stand under it approximately in the middle. It is not shown in my drawings.

Now we make the second half of the corner rafter. To do this, we measure the size between the points "C" and "D" (see Fig. 19):

Figure 19

We take a board of suitable length, make the top cut at an angle β, measure the distance "C-D", make the bottom cut at an angle α. We install the second half of the corner rafter and sew it with the first nails (100 mm). We drive the nails into a run-up after about 40-50 cm. The result is shown in Fig. 20:

Figure 20

The upper end of the second half of the corner rafter must be cut down again. We do this with a chainsaw right in place (Fig. 21):

Figure 21

In the same way, we make and install the three remaining corner rafters.

STEP 9: We install racks under the corner rafters. First of all, it is imperative to put a rack resting against the junction of the corner offset with the floor beam (see Fig. 22):

Figure 22

If the length of the span covered by the corner rafter (its horizontal projection) is more than 7.5 meters, we put more racks at a distance of about ¼ of the span from the top point of the corner rafter. If the span is more than 9 meters, add racks in the middle of the corner rafters. In our example, this span is 5.2 meters.

STEP 10: We install two central rafters of the hips. At the beginning of the 8th step, we already pulled the laces to measure them.

We make the rafters in this way - we measure the angle of the lower gash "γ" with a small one, we calculate the angle of the upper gash "δ":

We measure the distance between the points "K-L" and make a rafter along it. We cut the ends at the corners we have determined. After that, the upper end must be sawed again (sharpened) taking into account the angle "φ", which is also measured using a bevel (see Fig. 23):

Figure 23

STEP 11: Adding takeaway to the corners. We make the most extreme extensions that do not reach the Mauerlat lightweight, from a board 50x200 mm (see Fig. 24):

Figure 24

STEP 12: We install the guards. How to make sprigs, I described in detail in the first article about the hip roof. Here the principle is absolutely the same, so I will not repeat myself (see Fig. 25):

Figure 25

We fasten the sprigs to the corner rafter using a 135 ° metal corner, bending it if necessary.

After installing all the sprigs, it remains for us to hem the cornices from below and make a crate. We have already talked about this many times.

Hip roof with hanging rafters

Hip roof with hanging rafters: we study the device

Structures with hanging rafters are in demand when building a roof supported only on the outer walls of the house. This principle of construction is applicable for both gable and hip roofs.

Design features of the hip roof

The calculation and construction of a hip roof is much more difficult than the construction of single-pitched and dual-pitched structures. The four-pitched hip roof has two slopes in the form of a trapezoid, and two triangular slopes (hip). This configuration allows you to withstand high wind loads, reliably protect building structures from external influences. In addition, the resulting spacious attic space can be used as a living space (windows for natural light are mounted on the roof slopes).

A four-pitched roof with a ridge run can be erected in two ways: with layered or hanging rafters. The use of layered roofs allows you to make the roof lighter, simplifies the calculation and installation. But in this case, it is required that the building has a load-bearing middle wall. Hanging rafters in the construction of a hip roof can be used with a small width of the building and the absence of internal walls. The operational load is transferred to the outer walls of the building.

The angle of inclination of the slopes of a four-pitched roof with hanging rafters should be more than 40 °.

The hanging rafters of the hip-type roof rest either on the floor beams or on the Mauerlat. The design of the truss system requires accurate calculations and the preparation of detailed drawings indicating the principles of installation of fasteners. For small buildings of the correct geometric shape, calculations can be performed independently, in other cases it is recommended to turn to professionals, since project errors will cause a significant decrease in the reliability of the roof during operation.

At the first stage of calculations, it is necessary to choose the angle of inclination of the hip roof, which directly affects its height. For a system with hanging rafters, the optimal angle of inclination is 40 - 60 °. The higher the ridge is located, the more material will be required to build the roof. At the same time, a high roof is the best option for regions that are characterized by a large amount of precipitation. A flatter roof has less windage and better resists wind loads.

When choosing the angle of inclination of the hip roof, it is recommended to adhere to the golden mean rule and proceed from aesthetic considerations. You can choose the angle of inclination of the slopes, and based on this, calculate the height of the ridge. Or vice versa, determine the desired height of the roof, and then calculate the angle of its inclination.

When calculating the hip roof, it is required to ensure the correct positioning of the ridge run. It should be located strictly parallel to the load-bearing side walls, exactly along the central axis of the building and equidistant from the end walls. Otherwise, the center of gravity of the roof will be shifted, which will lead to an uneven distribution of the load on the truss structure and load-bearing walls, which is fraught with deformation and destruction of the roof.

The drawings prepared as part of the development of the project must contain information about the location, cross section, shape and size of all elements of the truss system. Their appearance and design features, attachment features, span width, ridge length, roof height are taken into account.

Roof truss system

The main elements of the rafter system of the hip-type roof include:

mauerlat / floor beams (support for rafter legs);
ridge run (an element that, together with the rafters, determines the configuration of the roof);
ordinary side rafters (connect the ridge and load-bearing walls);
diagonal (corner, slanting) rafters (directed from the corners of the walls to the ridge);
central rafter hip;
sprigs (shortened rafter legs connecting the rafters with the Mauerlat);
struts and racks (used as additional supports);
crossbars (provide a rigid connection between the rafter legs in pairs);
sprengel (acts as an additional support for the diagonal rafter).

During the construction of a hip roof using hanging rafters, a ridge run is not installed. Instead, central trusses are mounted - rafter legs connected by crossbars for rigidity. The rafter system in the central part of the future hip roof is carried out in exactly the same way as in the construction of a gable roof. Roof trusses are recommended to be made on the ground according to a pre-prepared template in order to accurately comply with all dimensions. When installing trusses, it is necessary to check the verticality of each structure. It is important that the extreme truss trusses are at the same distance from the corresponding end walls of the building: this will ensure the correct geometry and symmetry of the hips.

After mounting a row of trusses in the ridge part of the resulting system (on both slopes), bars or boards are mounted that connect the trusses to each other. Then, rafters are attached to the extreme trusses, resting on the corners of the building. At the next stage, the central hip rafter is mounted (on each triangular slope) and the sprigs.

Roof trusses can be based on a Mauerlat or floor beams. When developing a project, it should be borne in mind that in the second case, the step of laying the beams must correspond to the step of the rafters. If the truss system provides for the installation of trusses on the Mauerlat, then the puffs located at the bottom of the trusses will not only ensure the rigidity of the structure, but can also serve as floor beams.

Lower tightening can be used if the span does not exceed 6 meters. If hanging rafters are mounted in a span of 6 to 7.5 meters, it is necessary to use crossbars in the upper part. With a span length of 7.5 - 9 meters, the upper part of the rafters should be tied with a puff using a headstock (rack). If the span is from 9 to 10 meters, the previous type of structure should be reinforced with struts.

Before proceeding with the installation of the truss system, it is necessary to check the geometry of the walls of the building. The upper part of the walls (Mauerlat, floor beams) must be located strictly horizontally.

Principles for the manufacture and installation of rafters

Installation of diagonal rafters is a key stage in the construction of a hip roof. It is important to ensure the correct geometry of the structure so that the truss system evenly distributes the operating loads of the roof.

The diagonal rafters are longer than the side rafters, they rest on the corners of the building frame, and in the upper part they are connected to the ridge element of the roof. Rafter half-legs (shortened) - sprigs, in turn, rest on the sloping ones. The rafters are subject to increased strength requirements, as they carry an increased load, acting as the supporting elements of the system. The total load on the diagonal rafters is twice that of conventional rafter legs. The lower part of the rafters rests against the Mauerlat or a beam laid at the corner of the wall, or rests on them, depending on the design principle - expansion or non-expansion.

Sloping rafters can be made from durable glued beams of the required length. But, most often, double boards are used, spliced in compliance with certain requirements. Splicing a diagonal rafter leg allows:

increase the resistance of the element to loads due to the double section;
to make a continuous beam of the required length;
unify the dimensions of the details of the hip roof.

Unification allows you to use the same material for the manufacture of diagonal elements as for standard rafter legs - the use of boards of the same standard size simplifies design solutions in the design and installation of truss system nodes.

One or two supports are installed under the diagonal rafter. The boards are spliced along the length so that the joints are located at a distance of 0.15L from the center of the support. Accordingly, the length of the boards for the manufacture of rafters is selected depending on the length of the span and the number of required supports. In particular, if a hip roof requires a diagonal rafter 10 meters long, it is recommended to use boards 7 and 3 meters long to position the post 1/4 of the span from the top end of the rafter. In this case, the structure will be able to withstand the design loads - it is not recommended to place supports under the middle part of the rafter.

The role of support under the diagonal rafter is a strut or stand made of timber or paired boards. The angle of installation is of no fundamental importance if the strut rests against a solid reinforced concrete floor (with laying a waterproofing layer). If the rack rests against the bed, the installation angle is usually 35 - 45 ° to the horizontal plane.

Additional supports are installed according to the following principle. A span of up to 7.5 meters requires the use of one brace. If the span is 7.5-9 meters, a support is installed at the bottom of the rafter, or a truss truss is mounted. With an increase in the length of the span, an additional support is installed. If the ceiling is not strong enough, it is necessary to lay an additional intermediate beam to stop the uprights.

Sprengel - a beam that crosses the angle formed by two walls adjacent to each other. A truss truss is a structure in which the rafters are supported by supports that lie on the trusses. The whole system is reinforced by two struts. For the manufacture of a trussed truss, a beam of 100 × 150 mm is used for beams, 100 × 100 for racks and 50 × 100 for struts.

Mounting the top of the diagonal rafters

The upper end of the rafters is attached to the ridge part of the outer truss truss when installing a system with hanging rafters. This may require the use of a sprengel or surf (a short board with a thickness of 50 mm or more), to which the ends of the diagonal rafters sawn at the required angle are attached. If the surf is placed indented from the ridge, you get a Danish half-hip four-pitched roof. The following types of fasteners can be used to fasten the rafters in the upper part:

The sprockets are attached to the rafters by cutting or with the device of cranial bars (the second option allows you to get a more rigid structure). The cross section of the bars, which are sewn onto the rafters on both sides, is 50 × 50 mm. The sprockets should be supported on the rafters with a shift so that the joints of the bars do not form at one point.

Hip roof truss system: device specifics and description of the installation process

Hip roofs offer an impressive list of compelling benefits. Among them are a spectacular shape, uniformity of heating and reliable protection of the house from precipitation. Due to the absence of gables, hip structures are not afraid of significant wind loads. Compared to gable options, there is much less reason to fear deformations. The list of pluses can be continued, but their flow is slowed down by a very weighty circumstance: the hip roof truss system does not please with the simplicity of the device. However, complexity will not stop an independent builder if he is familiar with the nuances of building a hipped frame.

Characteristic features of hip roofs

Hip roofs differ from their gable counterparts in that there are no vertical walls of gables in their design. The place of the pediments was taken by triangular slopes located at the ends, significantly reducing the real and visual volume of the roof. The economic effect of volume reduction is a moot point. When cutting large-sheet material into hip slopes, costs, on the contrary, increase. For example, laying a profiled sheet or installing a metal tile will force you to fork out for the purchase of a coating one and a half times more than for the arrangement of a standard pitched structure. The purchase of piece material will reduce the construction budget, because you won’t have to spend money on sheathing the ends of the roof.

By analogy with any of the building structures, the hip roof can be divided into simple geometric shapes. In the simplest version, without conjugations and valleys, she has two pairs of symmetrical slopes: two triangles and two trapezoids. On this basis, the hip roof received the parallel name "four-pitched".

Viewed from the front, its section resembles an ordinary triangular gable roof. In profile, the structure has a trapezoidal configuration, which can also be divided into a rectangle with two mirror-image triangles on the sides. The shape of the trapezoid depends on the architectural preferences of the owner. It is determined by the ratio of the length of the cornice overhang to the length of the ridge. The part of the structure, bounded by a rectangle, is constructed in accordance with hanging or layered technological roofing standards.

The hips that replaced the gables are set at a certain angle to the horizon, because. they are obliged to adjoin the inclined sides of the trapezium. It is in their device that the main snag of the hip truss system lies, because it will not work with the usual pitched method. After all, the ridge run does not completely cover the slope. Therefore, the rafter legs of the hips and the triangular parts of the large slopes associated with them literally have nothing to lean on with their upper heels.

The support for them will be special sloping rafter legs connecting the ridge run with the corners of the structure. If you look at the hip rafter structure from above, then the rafters will look like diagonals. The installation direction was the reason for obtaining the second technological name - "diagonal". Naturally, rafter legs of different sizes in length will rely on the diagonals, because. they are installed perpendicular to the roof overhangs. They have their own name - narozhniki.

Summing up the information, we get that the following will be involved in the construction of the truss frame for the hip roof:

Ordinary rafter legs, resting on the lower part on the Mauerlat or on the floor beams. Depending on the type of support, they can be hanging or layered.
Diagonal rafters connecting the corners of the roof and the edges of the ridge run. Note that they are used not only in the arrangement of the convex corners of the hip roofs, but also in the construction of the concave corners of the valleys.
Narozhniki, forming the planes of the hips and parts of large slopes adjacent to the rafters.

The installation of hanging and layered rafter legs is carried out according to the rules according to which a gable roof truss system is being built. We will deal with their diagonal counterparts and with rafter half-legs-spiders.

Diagonal rafter legs

Taking into account the diagonal arrangement, it is easy to guess that the length of the slopes is greater than the length of ordinary rafter legs. In addition, they serve as supports for the sparrows. In view of what the rafters are loaded one and a half times more than ordinary analogues. Therefore, it is customary to make them paired from two boards with a section equal to the same size of material for ordinary rafter legs.

Pairing of slanted rafters simultaneously solves three technical problems:

Allows you to safely increase the load due to the double cross-section of the bearing element.
Provides the opportunity to obtain a diagonal structural element of any length without sections weakened by building.
Eliminates the need for purposeful purchase of rafter timber.

Due to their length, diagonal rafters need additional supports, the number of which depends on the length of the rafter leg.

Supports for diagonal rafters

Regardless of the scale of construction, any scheme of the hip roof truss system includes supports to reinforce the diagonal rafter legs. If the design size of the swath is more than 9m, i.e. it covers a span equivalent in meters, its stability is provided by two additional supports. For smaller spans, one support located in the upper zone of the span is sufficient.

As a support for the diagonal rafters can be used:

Rack installed vertically directly on the ceiling. A piece of waterproofing is laid between it and the ceiling if the rack is to rest against a reinforced concrete slab.
Strut. It is installed, as it should be for braced rafters, at an angle, the size of which is allowed to vary from 45º to 53º. The magnitude of the slope does not play a special role. It is important that the brace itself supports the rafter in the most loaded area. The lower heel of the strut rests on the bed.
Sprengel. It is a T-shaped short beam of timber, turned upside down. It is used in the construction of large spans that require two or more reinforcing supports. The sprengel is installed so that its base is perpendicular to the rafter. It is located at the bottom of a large span closer to the corner of the roof. Instead of a sprengel, a regular short stance can be used.

They make additional supports again from a double board or bar, installed at the most loaded points.

The nuances of supporting slanting rafters

The upper heel of the diagonal rafter rests on the ridge run in various ways. The choice of method depends on the design features of the truss system:

In truss structures with one run along the central axis of the roof, the diagonal rafter legs rest directly on the run consoles.
In truss systems with two runs and plank rafter legs, the diagonal rafters rest on a truss, which in turn rests on both runs.
In truss frames with two runs and rafters made of timber, in addition to the sprengel, a surf is used - a plank shorty that stitches ordinary rafter legs in the ridge area. The thickness of the reinforcing shorty is from 5 cm or more.

The heel of the diagonal rafters for landing on one of the listed upper stops is hemmed in fact. Fastening is done with nails. If necessary, fixation can be strengthened with wire twists or metal clamps.

The lower heels of the braids can rest against the corner of the Mauerlat or a specially installed corner beam. You can just lean on them. Diagonal rafter legs are fastened with metal brackets, nailing over a wooden lining or corners.

Narozhniki and methods of their device

The spears form hips and triangular parts of large slopes. The top of the half-leg rests on the rafter, the lower heel on the mauerlat, mortise beam or wooden floor beam.

Installation of sprockets can be carried out:

By cutting. In the braids, nests are chosen so that the half-legs of adjacent slopes are not located opposite each other. It is recommended that the distance between the cuts be at least 20 cm. Therefore, in the installation step, the spawners are allowed to move so as not to cut down the nests at one point.
By installing cranial bars serving as supports for the semi-legs. Bars 50 × 50mm are built up along the lower edges on both sides of the diagonal rafter. Their presence allows you to abandon the cuts, significantly weakening the bearing element.

The second option is easier to work with and is preferable due to the increased rigidity of the structure. In addition, it absolutely does not oblige to change the installation step of the half-rafters: they can be located opposite each other. The sprigs are attached to the Mauerlat or beams in the same way that they used to install ordinary rafters.

Elementary hip truss system

The easiest way to crown a suburban property with a four-slope structure is to buy and install ready-made roof trusses. However, it is much more interesting, more useful, cheaper to do the installation of a hip roof and a truss system suitable for it with your own hands. Especially if it is planned to build it over a small outbuilding, gazebo or summer kitchen. On simple structures, it is even worth practicing before applying efforts to more responsible objects.

Note that in the example below there is no overlap, the attic is not fenced and there is no insulation. Snow practically does not linger on the slopes, i.e. the rafter legs are subject to the minimum load by their standard standards. The principle of scatter between the spawners has not been preserved. All nodal connections are made with a nail trap and metal corners. The contractor will need a 5 × 25 cm board for the manufacture of rafter legs and a run, as well as moisture-resistant plywood for the construction of a continuous crate, because the building is planned to be covered with bituminous tiles.

Stage 1: Modeling and design

Regardless of the architectural complexity of the building structure, it needs a project. It will help determine the optimal form and save you from buying unnecessary materials. For a simple hip roof with a standard truss system, super-complex drawings are not required, but at least a simple sketch is necessary.

Instruction for simplified design:

We measure the width / height / length of the building. According to the data, we draw the profile and full face of the building on a sheet of paper on a scale, for example, 1:50. This means that all dimensions will need to be divided by 50. That is. the wall of the house with dimensions of 5 × 2.5 m on a home-made drawing will be shown as a rectangle with sides of 10 × 5 cm. If it comes out too small, you can choose a larger scale - 1:40, 1:25, etc. It is advisable to duplicate the finished sketch a couple of times in stock.
We choose the optimal height of the roof and the angle of its steepness. To do this, on one of the duplicates of the sketch, draw several options for the outline of the roof. We determine the most successful and measure the angle of inclination of future slopes with a protractor.
We mark on the duplicate of the sketch the installation points of the layered rafters, this is a step. We need to divide both walls into equal segments. It is not necessary that the installation step under the hip and pentagonal slope be the same. In the example, the distance between the rafter legs on both walls of the building is 20 inches, which is 50.8 cm. In fact, the installation step can vary from 0.4 to 2.1 m. However, we note that too often installed rafters will significantly increase the consumption of material, and too rarely will force the structure to be reinforced with an additional counter-lattice.
Decide on the length of the skate. Let's draw it on a duplicate of the template, given that the ridge beam must connect a whole number of pairs of rafters. Set aside equal distances from both edges of the long walls.
We transfer all the results to the main sheet and calculate how much material is needed. We consider the length of the rafters on the outer sides, taking into account the length of the cornice overhangs of 40-50 cm. Plywood consumption is calculated by the number of solid panels per each plane of a hipped roof.

By the number of rafters, we calculate the number of fasteners. We need nails in literally all nodal fasteners. There should be a pair of corners for each rafter leg. Do not forget to buy a board with a small margin in case of flaws in your own work. To install a hip roof on brick and foam concrete walls, you will need a bar for the construction of a Mauerlat. It is not needed if the installation of the truss system is carried out on wooden walls.

Stage 2: Construction of the main part of the hip roof

First of all, we will build auxiliary scaffolding on the basis that a full-length home master should be placed between the plane of a home-made stand such as a high bench and a ridge run.

The start of the installation of the truss system for the future hip roof is the installation of the ridge part of the structure:

We nail to the walls of the building connected with the hips along an auxiliary board, one edge of which should coincide with the central axis. Between the boards we stretch the lace, repeating the central axis.
We try on a pair of rafters to the end of the building. They should intersect directly under the lace. In fact, we outline the lines of saw cuts of the upper heels, not forgetting that there will be a run 5 cm thick between the rafter legs.
According to the templates obtained, we prepare layered rafters.
We install the rafter legs in pairs according to the marks of the main part of the system. Temporarily fasten with one nail.
We install the ridge run between the upper heels, which previously freely leaned against each other.
We nail the rafters to the run.
We attach the bottom of the rafters to the Mauerlat or the upper crown of the house with metal corners.

We dismantle the auxiliary boards, we will no longer need them.

Stage 3: Construction of hip slopes

We fasten the hip part of the rafter system in the same way: the lower heels are cornered to the Mauerlat or to the upper crown, the upper ones are fixed with nails. We work in the following sequence:

We try on the first slope rafter to the slope, we mark the cut line in fact. The bottom of the rafter must pass exactly through the corner marking point.
Saw off the marked excess. We nail the diagonal leg to the ridge console, fix the bottom with corners.
We do the same with the other three braids.
We fill the hip ramp with sprigs, having previously tried on each detail to the right place and sawed off the excess.
We install pentagonal ramps.

At the end of the work, the rafters through one are screwed with wire twists to the wooden corks laid in the walls or to the second crown, so that the structure is not torn off by a strong gust of wind. There is a way to lay twists of annealed wire into the masonry during the construction process for the subsequent fixation of the truss system. On top of the wire twist there should be three more rows of brickwork or two rows of foam blocks.

A crate is laid on the finished rafter system. In the case of a soft roof, as in the above case, the crate is made solid from inches, plywood or similar plates as a coating. Between the plates or boards leave a gap of 3 mm. For hard materials, the crate is constructed from a bar with the step recommended by the instruction.

Construction of complex hip roofs

The principle of the construction of hip roof frames with a more complex architecture is slightly different from the above example. The sequence of work is exactly the same. True, the layered rafter legs are still more reasonable and more reliable to fix with the help of cuttings. It is highly desirable to use supports for diagonal rafters. And before mounting the ridge part, support frames are installed with a bed at the bottom and a ridge run at the top. Another change in the angle of inclination of the slopes when supported by a notch should be taken into account at the design stage.

Hip roof: truss system and structure installation

A four-pitched roof is familiar to most developers. But its second name - hip can confuse even an experienced builder. It's all about the triangular end slopes (hips), which replaced the vertical gables.

Why did the creators of such a roof need to complicate the construction of a gable roof, you ask?

There are several reasons for this:

The aerodynamics of a hip roof is better than that of a gable roof. Therefore, it steadfastly resists strong winds.
Triangular slopes make the roof rigid and reliable.
The hip design makes it possible to install wide cornice overhangs along the perimeter of the building, protecting the facade of the building from rain.
The aesthetic appearance of such a roof is better than a gable roof.

The device and varieties of hip roofs

In order to understand how a hip hipped roof is arranged, consider its main elements.

As can be seen from the diagram, the main elements of this roof are the same as those of a gable roof. There is a ridge run, rafters and mauerlat for attaching them to the wall, racks that support the ridge and struts that unload the middle part of the rafter legs.

The wind beam holds the rafters together during the installation of the roof, and the filly lengthens them, forming roof overhangs. Differences begin with diagonal rafters forming hip slopes. Short rafter legs adjacent to the diagonal rafters are called rafters. To reduce the deflection of long hip beams, sprengels are placed under them. This is the name of short T-shaped racks-stands, cut into the Mauerlat with their ends.

Depending on the width of the building and the presence of internal walls on hip roofs, two types of truss structures are used:

The name of each speaks for itself. Hanging rafters rest only on the outer walls. In the upper and lower parts, they are connected by horizontal tie-beams, which ensure the rigidity of the structure. The rafters in the ridge joint are supported by vertical posts, in the middle part - by struts, and the ends are placed on the outer walls.

In addition to the classic hip roof, there are several varieties of it, created for reasons of aesthetic appeal:

half-hip 4-pitched (Danish);
gable semi-hip (Dutch);
tent (4 identical hip slopes);
hip with a broken slope.

Calculation features

The process of calculating a hip roof can be divided into three stages:

The choice of the angle of inclination of the slopes, depending on the type of roofing material.
Determination of the lengths of the structural elements of the roof, based on the drawings of the cross-section of the building and the plan of the floor to be covered.
Selection of the cross section and pitch of the rafters along their length, taking into account the type of wood used and the normative snow load of the construction region.

The angle of inclination of the slopes depends on the material of the roof. Therefore, when making a diagram of a truss structure, it is necessary to take into account its minimum value recommended by the standards (in degrees):

for slate - 22;
soft tiles - 11;
metal tiles - 14;
corrugated board - 12;

For a roof made of a waterproof membrane, the angle of inclination of the slopes can be any. Based on the minimum allowable slope value, its actual value is chosen depending on the purpose of the attic space.

If a living space is built under the hip roof, then its slopes should have an angle of inclination that allows comfortable movement within the "residential zone".

The actual length of the structural elements of the roof is most easily determined by drawing the truss system in a scale convenient for measurements.

Knowing the length of the rafters, their pitch and cross section can be found in the table. Here the dependence of the geometric dimensions of the rafters on the type of wood and the magnitude of the snow load of the construction region is indicated.

This table can also be successfully used in reverse order. By choosing the pitch and section of the rafters, the type of wood and the amount of snow load, you can easily find the maximum length of the rafters allowed by the standards.

The cross section of the Mauerlat beam must be no less than the cross section of the rafter leg. Most often it is 10x15 cm, 15x15 cm or 15x20 cm. The cross section of the ridge beam is usually equal to the cross section of the rafter legs.

For the lathing, a board 25 mm thick is used, stuffing it at the interval recommended for the selected roofing. For the installation of a solid flooring on the roof frame, an OSB plate with a thickness of 12-15 mm is used.

Mounting Features

Judgments circulate on the Internet that the installation of a hip roof is very difficult and time-consuming. There is some truth in this, but, in essence, the assembly of this structure is not much different from the construction of a conventional gable roof.

The process of installing a hip roof truss system includes several stages:

1. A mauerlat is laid along the perimeter of the walls. In this case, it is placed on steel threaded studs embedded in the masonry and tightened with nuts. At the docking sites (at the corners of the house and at the splicing points), landing planes are selected on the Mauerlat, cutting off half of the beam.

2. The further sequence of work depends on the width of the overlapped span (roof area). This point must be taken into account at the stage of drawing up a drawing or a roof diagram.

Racks supporting the ridge beam can be dispensed with if the width of the building (span) is less than 7.5 meters. With a house width of 6 to 7.5 meters, the hanging rafters in the upper part must be connected with a crossbar (a beam with a section of 50x100 mm).

If the width of the building is small (up to 6 meters), then lower puffs (floor beams) will be sufficient to ensure the rigidity of the truss system.

Having laid the Mauerlat, the central axis is marked on the end walls. Two extreme racks are set along it and fastened with temporary struts to the floor beams. If the building is covered with panels, then a central beam is laid along them (the cross section is the same as that of the Mauerlat). The lower ends of the extreme racks are fixed on it.

Intermediate racks are placed in increments of 1-2 meters. If the house is covered with beams, then the racks can be mounted on them, fixing them with brackets or self-tapping screws.

3. A ridge beam is laid on the racks, the places for installing the rafter legs are marked on the Mauerlat and they are mounted. To attach the rafters to the Mauerlat, a notch is used (a cutout is made on the rafter leg for tighter contact).

4. The hip (sloping, diagonal) rafters are fixed with the lower end to the Mauerlat, and with the other end to the junction of the ridge beam and the extreme ordinary rafters.

After that, short rafter legs (spiders) are attached to them.

Anyone who wants to make a hip roof with their own hands must remember that the main attention here is paid to the quality of assembly of nodes. It is very responsible to approach the installation of the ridge beam, the joining of the diagonal rafters with the ridge and with the sprigs.

On large roofs, the standard length of the beam (6 meters) is not enough to make a solid diagonal rafter. Therefore, it is assembled from two parts, securely fixing them together.

The overhangs of the hip roof are made by stuffing on the rafter legs trimmings of a beam or a thick board (filly) that extend beyond the perimeter of the walls by 50-100 cm.

Having completed the installation of the truss system, the crate is nailed to it and the roofing material is laid.

Mauerlat is a special belt laid along the perimeter of the upper end of the external load-bearing wall of the building and designed for attaching rafter legs. Wood is considered a traditional material for the manufacture of this element of the truss system, but if a metal frame is installed under the roof, then metal rolled metal - an I-beam, a channel or profiles can also be laid as a Mauerlat.

Mauerlat for do-it-yourself installation is relatively easy - there are several different technologies for this. But at the same time, it should be remembered that the more reliably it is fixed to the wall, the longer the life of the entire structure of the truss system will become.

Mauerlat purpose

Mauerlat serves to securely connect the box of the house and the structure of the roof and roof. In addition, it is designed to evenly distribute static loads around the entire perimeter of the building from the weight of the roof, consisting of a massive truss system and a roofing “pie”.

Another task that this element of the truss system is designed to perform is to counteract the load from the roof sail, which can contribute to damage to the structure or even its breakdown during strong winds. In a word, the roof is "attached" to the walls.

You can find roofs, the rafters of which are laid on the upper part of the walls or fixed to the floor beams without installing a Mauerlat. In this case, the load from the rafter legs will be concentrated in the places of their support without being distributed over the entire wall, which can eventually lead to damage to the wall structure.

Since it is a connecting link between structures made of materials of different characteristics, and high loads fall on it, its installation must be approached with special responsibility.

Mauerlat manufacturing materials

Mauerlat can be made of wooden beams, boards, logs, as well as metal profiles - channel, pipe, I-beam.

Most often, Mauerlat is made from timber. Its cross-sectional size to a certain extent depends on the size, and hence the weight of the future roofing system, as well as on the size of the rafter legs.

However, given that the mauerlat must fit firmly along the end of the wall, distributing the load, the hiding or bending stresses in it are small, and the wood copes well with the compressive load. Therefore, in most cases, the Mauerlat does not require complex calculations of the Mauerlat section, and bars with sides that are multiples of 50 are usually used, starting from 100 × 100.

The table below shows the dimensions of the lumber sections most commonly used in the construction of roof structures in individual construction.

Table of sizes of wooden elements of the truss system:

Elements of the truss system	Lumber section, mm
Mauerlat	Timber 100×100, 100×150, 150×150, and sometimes more.
rafter legs	Board or timber 60 × 150, 80 × 150, 100 × 200 - according to the results of calculations
Runs	Timber 100×100, 100×150, 100×200.
Puffs (crossbars)	Board 50×100, 50×150.
Racks	Beam 100×100, 150×150.
Struts, filly, eaves box board	Board 50×100.
Wind end and hemming boards	Board 20×100, 25×150.

Beam for Mauerlat must be chosen carefully, paying attention to its evenness and integrity. Behavioral, deformed lumber should not be purchased even for the sake of economy, since it will be more difficult to install it on even wall surfaces without creating internal stresses in it. The wood should not have deep and wide cracks and knots.

Knots are dangerous not only because they differ from all wood in their density and the release of resin from them, as many people think, but also because they significantly weaken the timber. In addition, if a rafter fastener falls on a knot, it will be more difficult to screw a fastener into it or hammer a bracket, and besides, they will not hold well in such a wood structure.

Boards fastened together are used for lighter truss systems that do not have an insulating "pie", for example, when building a country summer house. For this version of the Mauerlat, for example, boards with a thickness of 30 ÷ 50 mm, laid in one or two layers, are suitable.
Mauerlat is rarely made of metal elements, but profiles are sometimes used for combined options, which include both wood and metal.

When using this option, the load from the rafters is distributed not only to the wood, but also to the pipe laid on top of the timber through wooden liners and pulled to the Mauerlat with clamps. When choosing pipes for strengthening the Mauerlat, it is necessary to adhere to some criteria for their selection:

- since the pipes will be passed through through holes in the lower part of the rafters, they should not have too large a diameter - 40 ÷ 50 mm is enough.

- it is necessary to take only a new pipe, and before installation it must be coated with anti-corrosion paint.

Holes in the rafters for the passage of the pipe must be made, departing from their lower edge by about 100 ÷ 120 mm.

Cutouts are made in the wooden Mauerlat, against the bottom of which the end side of the rafter leg will rest. Sometimes on the Mauerlat board, holes for installing rafters are formed by fixing at a certain distance from each other pieces of timber with a height of 80 ÷ 100 mm. The width between the installed segments of the bars should exceed the thickness of the rafter, by about 8 ÷ 10 mm, so that it freely enters the prepared gap.

Due to the fact that the rafters are not rigidly fixed to the Mauerlat, but are installed on sliding fasteners, the system will be able to move slightly when the structure shrinks.

This diagram shows an option using a combined version of a Mauerlat, consisting of a wooden one and a pipe extending beyond the bearing walls along their length. This design feature allows you to immediately make the basis for a protective visor on the gable part of the roof.

The main ways to install Mauerlat

Having chosen the material for making the base for the rafters, you need to decide whether the reinforcing belt will be poured along the top of the wall. This structural element is reinforcing and is provided, as a rule, on block, brick or backfill walls, giving the roof a reliable foundation. If the walls are monolithic, or the brickwork is made in several rows in thickness, then the reinforcing belt is abandoned in order to simplify work, save money and facilitate the entire structure of the house.

Thus, there are two types of arranging the base for the Mauerlat - with and without pouring the reinforcing belt.

To ensure high-quality ventilation of the attic space and avoid decay of wooden structural elements, experts recommended fixing the Mauerlat 300 ÷ 500 mm above the attic floor beams.

Mounting the Mauerlat to the walls can be done in various ways, depending on the existing base:

The mauerlat beam along the entire perimeter of the building is rigidly connected into a single frame. Since lumber usually has a standard length of 6 m, Mauerlat is assembled from several pieces of timber. They are spliced together with an oblique cut or half a tree, and the junction is additionally fastened with self-tapping screws, screws or wooden dowels.

The corner nodes of the frame are fastened with metal plates or brackets. The frame can be additionally fixed with brackets to the wall. One side of this element is driven into the Mauerlat, and the other into the wall. In the presented Mauerlat mounting scheme, this fixation option is shown on the left side.

The connection in half a tree can be made on a stud embedded in the wall in advance, or with anchor fasteners driven into the through holes of the combined parts of the timber.

This type of fixing the Mauerlat on the walls is possible without a reinforcing belt.

On the right side of the above diagram, the installation of a beam on a reinforced concrete belt is shown, into which studs are embedded at a certain distance to fix the Mauerlat on them.

This installation method is used for light filling walls or for those built from foam concrete and gas silicate blocks. In such a design, the main load from the rafter system falls on the reinforcing belt, and evenly distributes it around the entire perimeter.

Let's consider both cases - with and without a reinforcing belt, in more detail

Installing a Mauerlat on a wall without a reinforcing belt

Basic mounting and mounting options

There are four options for installing a mauerlat on a brick wall without a reinforcing belt. The simplest and therefore most common when the beam is fixed on top of the wall to the waterproofing material:

- For the entire thickness of the wall surface, when the walls are one brick thick.

- At the level of the inner surface of the wall, in which a wooden cork ¼ brick deep is embedded below the upper end. In this case, the bracket is driven into the Mauerlat and the cork.

- At the level of the inner surface of the wall, on the upper face of which, in front of the Mauerlat, from its outer side, a wooden bar-cork of a smaller cross section, treated with a bituminous primer, is fixed.

- At the level of the inner surface of the wall, on top of a cork board previously fixed on it, having a brick height.

The installation of a wooden Mauerlat on the wall is thought out in advance, taking into account the preparatory stage, which is carried out even during the laying of the walls:

The masonry rises above the floor beams by three or four brick rows. The surface of the wall must be flat. Then another row of bricks is laid, but on the inside of the wall, instead of a brick, a processed cork bar is installed, having a thickness equal to the height of the brick.

Then, another brick row is laid on top, overlapping the auxiliary wooden element.

Further, a waterproofing material is laid along the inner edge of the wall, on top of which a Mauerlat beam is laid. On the rest of the width of the wall, next to the Mauerlat, another row of bricks is laid - this will protect the wooden part from external moisture. On this horizontal side, the beam must also be separated from the brick by a layer of waterproofing.

After the mortar in the masonry has completely hardened, a bracket is driven into the Mauerlat and the auxiliary cork bar, fixing the wooden base on the wall.

rafter mount

In the second case, the masonry of the wall is made entirely of bricks to the required height. When laying the next row, approximately in the middle of the wall thickness, wooden plugs treated with bitumen are mounted, and a “shelf” for the Mauerlat is left on the inside. On the outside, next to the cork, a brick is laid. Further, waterproofing is spread over the surface, and a Mauerlat is fixed on top of it, which is fixed with brackets to the plugs.
In the third option, all work is carried out in the same way as in the second, but the masonry ends two rows before the desired height. Then, at the level of the inner edge of the end of the wall, corks are embedded, impregnated with bitumen, having a width greater than the width of the Mauerlat, by about 50 ÷ 60 mm, and a height equal to the height of the brick. Next to them, a row of bricks is placed to the width of the wall or with a protrusion outward. On top of the wooden cork, stepping back from its inner edge 10 ÷ 15 mm, a Mauerlat is laid, which is covered from the outside with one row of bricks.

The masonry is carried out with the bricks shifted outward by 30 ÷ 50 mm, while a stepped ledge is formed. Due to the fact that the outer brick row rises above the level of fixing the Mauerlat, additional thermal insulation of the structure is provided, which is not observed in the simplest version of fixing, when a wooden beam is simply installed on the waterproofed upper end of the wall.

It is worth focusing on waterproofing. This material is laid so that it separates the raw wood from the brick or other masonry material. For waterproofing, not only roofing material, but also linocrom, technonikol or hydroisol can be used.

Fasteners

Mauerlat can be permanently fixed to the wall in various ways - with brackets, wire, threaded rods or anchor bolts. How this is done will be discussed below.

wire stranding

If it is planned to fix the Mauerlat on a wire twist, then it is laid along the inner edge of the wall, and brickwork is made along the outer edge.

For work, you will need a steel wire - “rolled wire”, having a diameter of 5 ÷ 6 mm. It is laid at the stage of wall construction for 4-5 rows of masonry to the top, usually doubled. The free length of the ends of the wire on both sides of the wall should be left so much that it is enough to twist on the inner edge of the installed Mauerlat.

The twist itself is carried out using a mount or scrap.

Another option for fixing the Mauerlat with twisting is that the ends of the wire embedded in advance are passed through through holes drilled in the beam.

In this case, the wire is lifted from both sides to the edge of the wall, then it is bent and passed through the through holes of the Mauerlat from below, and then twisted so that the timber is pressed tightly against the upper surface of the wall. Fastening with twisting is done in steps equal to the installation step of the rafters - the connecting nodes are between adjacent rafter legs.

Staples

As mentioned above, in some cases, wooden plugs are embedded in the brickwork, which have a width and height equal to the size of the brick. Sometimes they practice a cork from a bar that runs along the entire wall parallel to the Mauerlat.

Corks must be treated (impregnated) with bituminous primer in the most careful way, in order to avoid atmospheric moisture absorption by the wood. The tab of wooden plugs has already been described above, and it remains only to consider attaching the Mauerlat to them with brackets.

In order for the bracket to fit neatly into the wood without splitting it in two, it is recommended to drill holes according to the markings, equal in diameter to the ends of the bracket. Then the bracket is installed in the marked holes and hammered into them.

Installing the Mauerlat on studs

Another option for attaching the Mauerlat is to install it on metal threaded studs or on reinforcement bars embedded in the masonry. This method of fastening is used if the walls of the building will have a high load. Studs are usually placed between the rafters at a distance equal to the installation step of the rafter legs. This distance can sometimes be increased, but in any case it should not exceed 1500 mm.

Fixing is done in the following order:

Segments of reinforcement are prepared, bent at the bottom in the form of the letter G, or studs, with a diameter of 10 ÷ 14 mm, in the lower part of which a horizontal segment is welded, having a length equal to the length of the brick. This form of the stud is necessary for a more rigid installation of the element in the masonry.
If the L-shaped version of the stud or reinforcement is selected, then it will be enough to deepen it into the masonry in three rows, that is, approximately 200 mm. If even studs are installed, then it is recommended to fix them by 350-400 mm.
The next step is to lay waterproofing material on the top row of masonry. In order for the waterproofing to lie flat on the wall surface, holes are cut in the rolled material at the points where the studs come to the surface.
Further, on the Mauerlat beam, markings are made for the holes through which it will be put on the studs. This process can be carried out quite simply, even without a ruler and a pencil. To do this, the beam is installed from above, on protruding studs, and it is tapped from above with a hammer in the areas where the fasteners are located. Dents should remain on the beam, through which through holes will be drilled. The diameter of the holes should exceed the diameter of the stud by 2 ÷ 3 mm so that the timber can be easily put on the fasteners, without distortions.
If the beam is installed on studs that have a thread in the upper part, then a wide washer is put on them and the nut is tightened. If the Mauerlat is mounted on reinforcement, then its free end must be bent at a right angle and fixed to the surface of the timber with powerful nails, which are hammered and then bent.

Anchors

This type of fastening is suitable for Mauerlat, which will have both a small and a high load. The main difference between the anchor fastening of the beam to the wall is that it does not require any preliminary embedded elements.

The anchor fastening consists of two elements - the expansion anchor itself, installed in a hole drilled for it in the wall and beam, and a screw that is inserted into it and on which a nut is screwed on top. When tightening the nut, the screw moves progressively upwards, together with the conical head, which pushes the "petals" apart and ensures a secure fixation of the fastener.

Installation work on installing the Mauerlat in this way is carried out in the following order:

A waterproofing material is laid on the wall.
A mauerlat beam is laid on top of it.
Next, markings are made, along which through holes will be drilled.
Anchors should have a diameter of 10 ÷ 15 mm, respectively, holes are drilled with a drill of 12 ÷ 17 mm. The drill must pass through the beam and go deep into the wall by at least 180 ÷ 200 mm.
The next step is to drive anchors with a screw part into the holes, onto which a nut is then screwed with a wrench, under which a wide washer is placed.

Fastening the Mauerlat to the reinforcing belt

A reinforcing belt for a rafter system will never be superfluous, even if the walls of the building are strong enough, since the mounting of the Mauerlat on it is as reliable and durable as possible. For some buildings, a reinforcing belt is simply necessary, for example, this applies to backfill or walls built from aerated concrete blocks. Aerated concrete is quite fragile and holds fasteners very poorly on its own.

Creating a reinforcing belt

A reinforcing belt for installing a Mauerlat can be done without helpers. Of course, if the work is carried out by one person, it will go much more slowly, but the main thing in this case is the opportunity to save money.

The reinforcing belt is a strip of concrete, inside which a metal frame of reinforcement passes. The width of the belt should correspond to the width of the wall, its height is 200 ÷ 250 mm, and it runs along the entire perimeter of the building. It is very important to provide that the number of fasteners must be equal to the number of rafter legs. Therefore, having calculated in the roof structure, the step of the location of fasteners embedded parts is calculated.

In order for the belt to be strong and not crumble, cement M400 ÷ 500 is taken to prepare the mortar, and the finished concrete from it is poured into the formwork in one go.

The mortar for pouring the reinforcing belt is made from cement, crushed stone and sand, in proportions of 1:3:3. Sometimes plasticizers are added to the mixture, which allow the poured solution to dry out evenly, reduce the amount of water used when mixing it.

Briefly, the process of pouring a concrete belt is shown in the table below:

Illustration	Brief description of the operation to be performed
	The first step for pouring the reinforcing belt is the formwork. It can be made from different materials. Most often, boards are used to mount this box, and bars are used to fasten them. This is the most affordable material, which, after the belt hardens, can be removed and reused. It is quite possible to use lumber of the third grade. In order for the poured solution not to seep into the gaps between the boards and into the joints between them and the wall, it is necessary to fix dense polyethylene on the wooden walls from the inside, which can be removed after the concrete has hardened.
	Another version of the formwork consists of two layers - this is plywood with a thickness of at least 10 mm, fixed to the wall from the outside, and insulation material installed from the inside of the structure and pressed against the plywood sides.
	It is advisable to install the insulation on the waterproofing sealant, and also glue the corner joints of the material with it, and then wait for it to dry. Then the solution poured into the formwork will remain completely inside the formwork.
	Another option is non-removable polystyrene foam formwork. It is a hollow block that is assembled into a single structure, and it is also desirable to fix them on the wall with a waterproof sealant. This design is both a formwork and a thermal insulation layer, which will reduce the impact of a powerful cold bridge through the concrete belt, and will keep warm in the attic. However, it makes sense to use foam blocks or an inner layer of thermal insulation on the formwork if the roofing system itself is completely insulated. From whatever material the formwork is erected, its upper edge must be carefully aligned horizontally using a level.
	The next step is to assemble the reinforcing structure. Along the inner walls of the formwork, along the upper and lower edges, with an indent from the top and bottom of 15 ÷ 20 mm, reinforcement is installed.
	The reinforcement is tied with a thinner wire, and the shape of the frame should generally repeat the shape of the inner space of the formwork.
	Between themselves, the individual parts of the reinforcement are fastened with a wire twist.
	In order to form the necessary clearance between the inner walls and the reinforcement system, and at the same time the structure was fixed in one position, special clamps are installed on the reinforcement rods.
	The "star" retainer is most often used to create a gap between the formwork wall and the reinforcement, which must be filled with a layer of concrete mortar. Clamps are produced under different numbers, which determine the thickness of the concrete layer that will separate the reinforcement and, in this case, the insulation, and in other cases, the outer edge of the wall or formwork to be poured. That is, the reinforcing structure is completely hidden inside the concrete and will be there completely safe from corrosion. The distance can be from 15 to 75 mm. Clamps are installed in increments of 500 ÷ 750 mm.
	Having completed the reinforcement of the formwork, at a distance equal to the step between the rafters, studs are installed, since in this embodiment they are embedded in the belt reinforcing the building. At the bottom of the hairpin should be L-shaped. On this bend, it is installed on the bottom of the formwork, in the middle part of the reinforcing structure, and is rigidly fixed with wire twists in two places - on the horizontal lower and upper lintels. The studs should stand strictly vertically and in one line, and rise above the future belt by the thickness of the Mauerlat, plus 50 ÷ 80 mm.
	The next step is to fill the formwork with concrete mortar, the surface of which is leveled along the walls of the box. The surface of the reinforced belt is leveled using a rule or a flat board.

After the reinforcing belt hardens (this process should take at least 15-18 days, or even more, depending on its thickness), you can proceed to the installation of the Mauerlat. This process will no longer differ from a similar operation, when the studs were embedded in the brickwork.

Video: the original solution to the issue of creating a reinforced belt under the Mauerlat on an aerated concrete wall

Other ways to install Mauerlat mounts

In addition to the above, there are other ways to fix the studs into the concrete of the reinforced belt for installing the Mauerlat.

log staples

A. The formwork is installed according to the same principle - from boards, plywood or foam non-removable blocks. In addition, the formwork walls can even be made of ordinary or aerated concrete bricks.

A reinforcing structure is also installed inside the formwork, but the studs are mounted differently before pouring into the mortar formwork.
The wooden walls of the formwork are fastened together with jumpers, installed at the same distance from each other - it must correspond to the fastening step. The middle is determined on the rails, at the found point a hole is drilled with a diameter of 2 ÷ 2.5 mm larger than the diameter of the stud.
Further, the stud itself is installed in the hole, having a height of 100 ÷ 150 mm more than the height of the belt and Mauerlat. From below, a stud is screwed into a nut - at the point of emphasis at the bottom of the formwork, that is, at the end of the wall of the house. Additionally, it is desirable to fix the stud with two nuts on the jumper itself in order to install it strictly vertically. The upper nut will then be easy to remove during the removal of the formwork. All other studs are installed in the same way.
When all the embedded elements are installed, the concrete mortar is poured into the formwork and leveled to the level of the walls.

If in this way the studs are installed in a formwork made of brick or aerated concrete, then wooden linings with a hole for the stud can be simply installed without even fixing them to the walls.

The concrete mortar in the formwork must also harden and gain strength for at least 15 days. Stripping is allowed only after the concrete has gained at least 70÷75% of branded strength.

B. Mauerlat can be anchored to the reinforcing belt in the same way as to walls built from other materials.

IN. If it is decided to fix the wooden beam with a wire, then it is screwed to the reinforcement, prudently installed inside the formwork and protruding from both sides of the belt.

Waterproofing layer under the Mauerlat

Waterproofing on the end part of the wall or on the concrete belt is laid to save the mauerlat beam from penetration into the wood by capillaries from building structures and, accordingly, to prevent decomposition processes. Waterproofing is recommended to be laid over the entire width of the wall, and for better adhesion of the material to the wall material, it is fixed to bituminous mastic, which in itself is a good waterproofing agent.

Holes are cut in the waterproofing material if it is mounted on top of embedded studs. The material is necessarily stretched, since it should not have folds or gaps between it and the concrete belt.

It is necessary to work with mastic carefully so as not to spoil the outer side of the walls, especially if it is not covered with a finishing material.

A few words about fixing rafters on the Mauerlat

As mentioned above, the purpose of the Mauerlat is to evenly distribute the load from the truss system over the entire surface of the wall. And how it will perform its function will depend on how the entire roof structure will behave when exposed to additional loads in the form of wind or snow drifts.

There are two ways to fix the rafters to the Mauerlat - hard and sliding, and which one to choose - first of all depends on which roof is chosen for installation - layered or hanging.

Rigid mount

Rigid fastening implies the complete exclusion of displacements of any parts of the system. It is most often used for a gable layered rafter system, which has additional support in the form of a capital partition inside the building.

For mounting a rigid structure, several types of fastening are used:

- Support beam and metal corners.

- Cutting the rafter leg into the Mauerlat and additional fastening with corners. The cut in the rafter should not be more than ⅓ of its width.

- Fixing the rafter leg with puffs and a metal corner.

- Cutting using a cutout in the Mauerlat and staples driven into the rafters and Mauerlat.

- Additionally, a notch on the rafter rested against the Mauerlat is often fastened with nails driven in at an angle.

It should be noted here that if the house is being built from a log or timber, the role of the Mauerlat is most often performed by the upper log, on which the rafter legs are fixed.

sliding mount

Sliding fastening is most often used in a gable hanging system, where the rafters rest only on the external load-bearing walls and do not have additional intermediate support. Sliding elements fixed to the rafters and Mauerlat allow the structure to move when the house shrinks or when external loads increase on it.

This design is especially important for wooden log cabins, since after construction shrinkage is inevitable, sometimes reaching up to 15%, and, as a rule, it passes unevenly.

The deformation processes of the elements of the truss system can also affect during its operation. So, in rainy times, wood can swell from moisture, as it is quite hygroscopic, and in winter frosts and in extreme heat it can dry out.

rafter mount

In addition to the sliding fastenings of the rafter legs on the Mauerlat, a hinge made of movable plates can also be installed as a ridge joint. This type of fastening of elements also helps the roof structure to remain intact when its geometry changes during periods of shrinkage or other fluctuations.

In order for the roof to be reliable in any situation, before starting installation, it is necessary to draw up its drawing and calculate all the parameters. If the construction process is carried out for the first time, then the best option would still be to seek help from specialists, since the strength of this structure depends on many nuances that are simply unknown to a beginner due to inexperience.

At the end of the publication - another interesting video - the home master shares his experience of installing a Mauerlat on a monolithic wall.

Video: do-it-yourself Mauerlat installation

Not every person, when arranging the roof of a house, wants to spend energy and money on a Mauerlat device. There are several points that allow the developer to do without this element of the roof structure.

If the installation of the truss system is carried out directly to the floor beams, then there is a point distribution of the mass of the roof. To do this, you need to use longer beams, they should be 40 cm longer than the width of the walls. When attaching the beams, you need to stretch the string, which will serve as a guide for the correct manufacture of grooves for installing the rafters.

The rafters are connected to the beam in several ways:

with a spiked tooth;
with the help of a persistent tooth;
focusing on the end of the beam.

How many teeth are required (1 or 2) will tell the angle of the slope of the sole of the rafters. The ends of the rafters are installed in the grooves, and they are fixed on the beams with metal corners or bolts. If the rafters are connected to the beam using a notch, then one tooth is enough.

In this case, it is necessary to follow several rules:

Installation of a roof on a wall made of brick or foam blocks

When installing the roof on the walls of these materials, they make an armored belt. If it cannot be done, then when erecting walls, steel wire is laid in them. The upper 3-4 walls between bricks or blocks lay pieces of wire around the entire perimeter. This fastening is not considered very reliable, the reason is that the wire is gradually loosened.

A liquid or chemical anchor, when installing a roof without a Mauerlat, is more reliable. There are 2 elements in its design - a polymer adhesive and a steel rod. It differs from mechanical one in the absence of bursting stress created in the wall material.

Important! A simple anchor will be held in the wall due to the expansion of the material and the resulting friction. In contrast, the chemical one penetrates into all pores, fixing the metal rod tightly.

For success, it is important to prepare a deep hole. Chemical anchors can be installed even in high humidity - it is permissible to carry out work even under water. The manufacturers claim that it is capable of serving for more than 50 years, they have only one limitation - nothing can be welded to it.

If welding is used, the metal will heat up from it, and the resins in the adhesive mass will melt, as a result of which the fastener will lose the necessary strength.

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