The structure of the truss system. Types and arrangement of a gable roof. Installation instructions for beds, racks, rafters, struts and puffs

A roof with two slopes is the most common option for completing the box of a private house. In its manufacture, it is important to correctly select the cross-sections of the supporting elements, securely fasten the nodes and choose the right type of construction. truss system gable roof does not have great difficulties and may well be made by hand.

Classification of truss systems according to the method of support

The structure can be classified in two ways. The first of them is the method of supporting the bearing elements. The gable roof truss system of the house in this case includes the following types:

with layered rafters;
with hanging rafters.

Kinds gable roof with layered and hanging rafters

Roofing with the use of layered rafters involves their support at two points. The design in this case avoids the occurrence of a serious spacer. To do the installation yourself, you will need the following basic elements:

rafter legs;
Mauerlat;
crossbar;
intermediate racks and struts with a large span of load-bearing beams;
crate and counter-crate;
overlays persistent bars.

At the top point, the installation provides for leaning on the crossbar. The installation also provides support at the lowest point - Mauerlat. You can assemble such a structure for a house with your own hands only in two cases:

Options for assembling a layered gable roof system

A layered system is possible if the distance between the gables is not large. That is, such an installation is suitable for a small house with your own hands. The greatest length of the structure, which allows the construction of a wooden crossbar without additional reinforcements, is 6 m. For large spans, it will be necessary to install metal beams as a crossbar. When using a wooden beam, it will be necessary to provide intermediate racks, which are located on average every 2 meters. This can be avoided only when using glued laminated timber of a sufficiently large cross section as a crossbar. In this case, a free layout of the space becomes impossible - the racks in the middle of the room cannot be removed.
The second option, when it is possible to install a layered gable roof system with your own hands, is the presence of a wall in the middle of the house. The device in this case provides that the beam, on which the rafters will rest at the top point, will transfer the load to the inner wall. In this case, the supporting structure should not be confused with the partition. The partition rests on the floors, and installing the wall of the house with your own hands involves resting it directly on the foundations. Such a device is suitable for buildings with sufficient width, where it makes sense to install a wall fence in the middle.

The second option is hanging rafters. They are more complex in calculation, but allow the device to roof space open plan houses. The design assumes the absence of a supporting wooden or metal bar in the upper part. Installation involves supporting the rafters only at the lowest point. In the upper part, the bearing beams are securely connected to each other. Installing such a system is like a farm. The design works on thrust, so it is important to prevent excessive horizontal load on the walls of the house. You can do this by doing the following:

the device of a monolithic belt along the edge of the walls;
it is necessary to make a reliable fastening of the Mauerlat of a gable roof to the wall of the house with your own hands;
to eliminate the spacer, a contraction is established.

Installation of a hanging truss system

The fight or screed becomes one of the significant elements of the gable roof of the house. It prevents the expansion of the walls under the action of thrust. The following types of fights can be distinguished:

located at the attic floor level;
located at the level of the attic ceiling.

It is worth noting that the second option provides less reliability, since the higher the element is mounted, the stronger the rafters have an effect on it. If the fight turns out to be too long, you need to make it stronger with your own hands. For this, additional elements of the gable roof of the house are installed - suspensions. They connect the skate to the middle of the puff, which prevents it from sagging.

The gable roof truss system with hanging rafters allows installation with pre-assembly of trusses on the ground, then raise them to the roof and fix them.

This option is only suitable if you have lifting equipment, since the finished gable roofs of the house will become too large and heavy to lift with your own hands.

Classification by type of slope

The second division can be made depending on how the ramp line is designed. The views here suggest the presence of two options:

Gable roof with broken and straight slopes

With straight slopes. The easiest way to do. Allows you to get the job done without any hassle. The disadvantage of this do-it-yourself roofing option is the reduction in attic space.
With broken slopes. Such types of roofing are more difficult to perform. It is assumed that there is a line along which the angle of inclination changes. The angle of inclination of the lower part of the slope must be made greater than that of the upper. Thus, it turns out to raise the ceiling of the attic and increase the free space. The installation of the roof is carried out with the installation of an additional crossbar at the fracture site.

These types involve a choice between them, depending on the wishes of the future owner of the building.

The main elements of the roof

The rafter system of the gable final part of the building consists of many elements. Installation should begin with a detailed study of each of them and the choice of their sections.

When installing elements under a metal tile or other coating, it implies the use of a bar with a section of 150x150 or 200x200 mm. It is this size that allows you to most optimally distribute the load. then you need to choose a method of fixing it depends on the material of the walls. There are several options:

The scheme of fastening the Mauerlat to the wall

Frame, timber or log walls do not require the installation of a Mauerlat. In the case of a frame building, the top framing of the walls serves as a support for the rafter legs. during the construction of fences from timber or logs, the upper crown becomes the Mauerlat. It is important to correctly fix these elements in the wall structure.
When used for the construction of lightweight concrete, additional reinforcement will be required. Lightweight concretes include materials such as foam concrete, cinder concrete, expanded clay concrete. They can collapse if the roof is not supported centrally on them. To evenly distribute the load, a monolithic reinforced concrete belt is poured along the edge of the walls. During work, a special wire, studs or bolts are laid in it, on which the Mauerlat will be fastened.
For brick means, it is possible not to provide a reinforced concrete belt. In this case, to connect with the strapping beam, a wire is inserted into the masonry, which is then wrapped around the Mauerlat and twisted. The second option - one row before the walls are cut into the masonry from the outside wooden blocks impregnated with an antiseptic. Such plugs and Mauerlat are fastened with staples. It is also possible to use studs and bolts, for fixing which will require pouring a monolithic belt.

An important point is waterproofing.

When installing, it is important to provide roofing material, linokrom or waterproofing at the junction of concrete or brick with wood. This is required to prevent the wood from rotting on contact with material of a different moisture content.

After fixing the Mauerlat, rafter legs are installed. Their cross section is selected depending on the pitch of the supporting beams, their span, snow load and type of coating. When installing a frame under a metal tile with a step of 60 cm, it is recommended to follow the following recommendations, depending on the span:

3 m - 4x15 cm;
4 m - 5=15 cm;
5 m - 5x17.5 cm;
6 m - 5x20 cm.

Table of average values of rafter legs

These are average values, in order to perform a more accurate calculation, it is better to contact a specialist or study additional literature.

There are two ways to fasten the rafter legs to the Mauerlat:

with a notch;
without her.

Fastening rafter legs to the Mauerlat with and without a notch

In the first case, they washed down on the strapping beam, in the second, a special plank is nailed to the rafters, which becomes a persistent bar. Further, for both methods, the work is performed in the same way. With the help of metal corners, the inclined beam is fixed so that it does not move relative to the design position along the Mauerlat. Additionally, nails are driven in at an angle.

Scheme of fastening rafters with wire and brackets

In addition, you will need to fasten the rafter to the wall. The implementation of this measure is provided for in the regulatory documents. You can do this in two ways:

on brackets (suitable for wooden buildings);
using wire twisting (a more time-consuming option, but the only one possible for stone houses).

You can perform fastening according to the norms through one leg. This is necessary for a more secure attachment of the roof to the box of the house.

If you do the work correctly, you can not worry about its condition even in the strongest winds.

Racks, ties, struts

Such elements are most often made of boards. The optimal thickness is in the range of 32-50 mm. Racks are an exception. Here you can use boards with a thickness of 50-100 mm. Fastening is carried out on studs or using support bars.

Gable roof truss system: design and nodes

A gable roof is the most common in construction. For proper installation, it is recommended to study the device of the gable roof truss system.

The device of the truss system of a gable roof

The gable roof truss system is designed for roofing in the form of two rectangles located at a certain angle to each other in the upper part of the structure. This design is often used in the construction of private low-rise buildings, various buildings for household and household purposes. At industrial and commercial enterprises, a gable roof is installed on buildings for various purposes, which have a significant length several times greater than the width. The design contains two slopes of different lengths. On the front side, a short slope with a large angle of inclination is installed, on the back - a long one, with a smaller angle of inclination. This configuration allows the main part of atmospheric precipitation to be directed to the non-working zone of the enterprise territory.

Figure 1. Scheme of fillies.

The construction of a gable roof is one of the low-cost options that does not require significant physical effort.

It is performed relatively simply with little experience working with wood material.

Typical bearing elements of the system, specific terms

Figure 2. Scheme of the crate.

In the manufacture of details of the gable roof truss system, softwood lumber is used. Hardwood is undesirable due to its high specific gravity. Most of the elements have specific names that are understood mainly by specialists:

Lezhen - timber with a section of 150x150 mm, 180x180 mm. Laid on the surface of the inner bearing wall. Designed for leveling the surface and distributing loads from racks.
The rafter leg, or rafter, is a piece of timber or thick board. The main element of the triangular roof structure, bearing the main load from snow, rain, wind and other atmospheric phenomena. The distance between the rafter legs can be from 0.6 to 1.2 m. The step size mainly depends on the plumb line of the roofing material, in some cases, the characteristics of the roofing material should be taken into account.
Mauerlat - a square beam with a side size of 150-180 cm. It is laid on the surface of external load-bearing walls. When installing, it must be fixed with anchor bolts or in another reliable way. Distributes the load from the rafter legs to the load-bearing walls.

All parts of a gable roof are interconnected in various ways. Previously, structures were assembled mainly using staples, nails, threaded studs. Now manufacturers building materials offer a wide range of different brackets for assembling roofs of any configuration. Most parts are fastened with self-tapping screws required diameter and length with reinforcement with special spikes in the brackets.

Additional elements of the rafter system

Figure 3. Scheme of an arch with three hinges.

In addition to load-bearing parts, additional reinforcing elements are used in the structures:

Filly (Fig. 1) - used to increase the length of the rafter legs. Are established in the lower part for the device of cornice overhang. The thickness of the filly is somewhat less than the size of the rafters.
Roof overhang, or cornice overhang, is a roof element protruding from the edge of the wall by about 40-50 cm. Designed to protect walls from atmospheric precipitation.
The ridge is an element that connects all the rafter legs of the system in the upper part. Installed in a horizontal position.
Sheathing (Fig. 2) - boards or bars installed for fixing the roof. They are located perpendicular to the rafter legs, additionally performing the function of their fastening. They take the main effort from the roofing material, distribute it to the rafters. For the device, it is desirable to use edged lumber. With limited funds, you can use unedged, clearing it of bark. If the roof is soft material, the crate is made solid. This option can be made from boards or plywood treated with protective materials from high humidity. When corrugated board is used, the crate is performed with a certain step, depending on the weight of the material and its design features.
Struts - elements made of timber or thick boards that reinforce the main structure. Distribute the force from the rafter legs to the bearing parts. The assembled structure of struts and puffs was called a farm - an enlarged part with the necessary margin of safety.
Racks - are made from pieces of lumber of rectangular or square section. Are established in vertical position under a descent of slopes. Load from corner connection The roof rafters are distributed through studs onto an internal load-bearing wall.
Puff - a bar or board that fastens the rafters in a hanging system. Creates a rigid triangle shape between rafter legs, compensating for sprawl.

For the manufacture of additional parts, you can use lumber with a section similar to that of load-bearing parts. In order to save money, you can calculate and purchase products of a smaller section.

Two typical ways to arrange truss systems

Figure 4. Scheme of connecting the lower ends of the parts.

The gable roof truss system can be arranged in two main ways:

hanging rafter system;
layered system.

The hanging system is used for buildings with a distance between the outer walls of less than 10 m, without an internal load-bearing wall in the middle of the building. In a different configuration of the building, a layered rafter structure is used.

If the building has columns located along one of the central axes, it is possible to use combined option. Rafter legs located above the columns are mounted with emphasis on the surface of the columns, hanging rafters are installed between them.

Hanging truss system

In structures of this type, the installation of truss beams is carried out on the surface of the outer walls. The disadvantage of this method is the occurrence of force, bursting the walls. To compensate for the load, the beams are pulled together by tightening. The design takes the form of a rigid triangle that retains its shape under the influence of loads. In some cases, floor beams can play the role of puffs. Such a scheme is used when arranging an attic in the attic space.

Hanging rafters can be made in various versions:

Scheme of the reinforced structure.

A simple version of the arch with three hinges (Fig. 3) - the design is a rigid triangle, the two sides of which are the rafter legs. The main load creates a bending force on the parts. The force on the third side is aimed at stretching the structure, so instead of a wooden part, a steel tie can be used. The connection of the lower ends of the parts can be assembled in various ways (Fig. 4), by inserting beams into a puff, using wooden elements or metal brackets.
Reinforced structure (Fig. 5) - a gable truss system used for roofing of large industrial buildings with a distance between walls of more than 6 m. This system is not suitable for use in small residential buildings. A design feature is the distribution of the puff weight on the skate. Since it is almost impossible to find solid lumber of the required length (6 m or more), the puff is made from segments. The connection of all elements is carried out by a straight or oblique inset. The central part is called the headstock. The connection of the headstock with a tightening is performed by a collet twist with the possibility of adjusting the tension.
The device of an arch with a tightening in the upper part of the rafters (Fig. 6) is used for equipment in the attic space of the attic. At the same time, the tensile force in the rafter beams increases. The lower ends of the beams are attached to the Mauerlat bars. The fastening should limit the movement of the beams to the sides along the beam, but allow sliding across. This ensures uniform load distribution and stability of the entire system. Rafter beams should form an overhang.

Many variants of hanging-type systems have been developed. Most are used for relatively small sizes buildings without load-bearing structures inside buildings. For larger buildings, a layered rafter system should be used.

Layered truss system

The main difference of this system is the installation of a vertical beam resting on an internal load-bearing wall located in the middle of the building. This design is necessary when a gable roof is installed on a building with a wall spacing of more than 10 m.

Figure 6. Arrangement of an arch with a puff at the top of the rafters.

A properly executed system of non-expanding rafter beams allows you to get rid of the forces that burst the walls. The surface of the slopes is subjected only to the bending force. There are 3 main options for the device of such systems. With all options, the lower ends of the rafters are attached according to the sliding support method. For insurance, an additional mount is installed between the support bar and the rafter leg.
You can use a steel strip, wire tie. The options differ in the method of connecting the upper ends of the rafters, docking with the ridge beam. One of the options involves laying rafters on a beam in the form of a sliding support with a cutout device. Mounting can be done using brackets or special brackets. The gable roof, arranged according to the following option, is the most popular because of the simplicity of the device. The top of the rafters can be made end-to-end or overlay with cutting grooves. The corner must be fastened in any of the available ways and fixed on the ridge beam. The third option involves a rigid connection of the run and rafters. For mounting on rafter legs, pieces of boards are stuffed on two sides. A large bending force is formed on the beam, but the load on the rafter beams is reduced.
A gable roof for a building with dimensions up to 14 m must have a reinforced truss system. One of the options for increasing strength is the installation of a strut. The part bears the load from rafter leg, experiencing a compressive force. To correctly select the installation position of the element, you need to measure the angle of 45-53 ° from the horizontal plane of the building. An additional support device turns an ordinary beam into a reinforced version, consisting of two spans. To install the struts, calculations are not required, you just need to fix it under the rafter, cutting out the joint angle with maximum accuracy.

Two device technology pitched roofs simple, everything can be done by hand. Work must begin with the installation and fastening of the base to the walls, then mount the gables. It is desirable to carry out work on the manufacture of rafter beams and enlargement of structures on the ground, to lift the assembled elements, install them on the building, and fix them with temporary fasteners. After assembling and installing all the elements, you should fix the crate and proceed with the installation of the roof.

Gable roof truss system: installation and diagrams

The gable roof truss system is designed for roofing in the form of two rectangles located at a certain angle to each other in the upper part of the structure.

Do-it-yourself gable roof truss system: an overview of hanging and layered structures

Rafters perform a number of significant roofing functions. They set the configuration of the future roof, perceive atmospheric loads, and hold the material. Among the rafter duties are the formation of even planes for laying the coating and providing space for the components of the roofing pie. In order for such a valuable part of the roof to flawlessly cope with the listed tasks, information about the rules and principles of its construction is needed. The information is useful both for those who are building a gable roof truss system with their own hands, and for those who decide to resort to the services of a hired team of builders.

Rafter structures for gable roofs

In the device of the truss frame for pitched roofs, wooden and metal beams are used. The starting material for the first option is a board, log, timber. The second is constructed from rolled metal: channel, profile pipe, I-beam, corner. There are combined structures with steel most loaded parts and wood elements in less critical areas.

In addition to the "iron" strength, the metal has a lot of disadvantages. These include heat engineering qualities that do not satisfy the owners of residential buildings. Disappointing need for the use of welded joints. Most often, industrial buildings are equipped with steel rafters, less often private change houses assembled from metal modules.

In the case of self-construction of truss structures for private houses, wood is a priority. It is easy to work with it, it is lighter, “warmer”, more attractive in terms of environmental criteria. In addition, nodal connections do not require a welding machine and welder skills.

Rafters - a fundamental element

The main "player" of the frame for the construction of the roof is the rafter, among the roofers called the rafter leg. Beds, braces, headstocks, girders, puffs, even Mauerlat may or may not be used depending on the architectural complexity and dimensions of the roof.

The rafters used in the construction of the gable roof frame are divided into:

Layered rafter legs, both heels of which have reliable structural supports under them. The lower edge of the layered rafter rests on the Mauerlat or on the ceiling crown of the log house. The support for the upper edge can be a mirror analogue of an adjacent rafter or a run, which is a beam horizontally laid under the ridge. In the first case, the truss system is called spacer, in the second, non-spacer.
hanging rafters, the top of which rests against each other, and the bottom is based on an additional beam - puff. The latter connects the two lower heels of adjacent rafter legs, resulting in a triangular module called a truss truss. The tightening dampens the tensile processes, so that only a vertically directed load acts on the walls. The design with hanging rafters, although it is spacer, does not transfer the spacer itself to the walls.

In accordance with the technological specifics of the rafter legs, the structures constructed from them are divided into layered and hanging. For structural stability, they are equipped with struts and additional racks. For the arrangement of supports for the top of the layered rafters, beds and girders are mounted. In reality, the truss structure is much more complicated than the elementary patterns described.

Note that the formation of a gable roof frame can generally be carried out without roof structure. In such situations, the alleged planes of the slopes are formed by slegs - beams laid directly on the bearing gables. However, we are now specifically interested in the device of the gable roof truss system, and it can involve either hanging or layered rafters, or a combination of both types.

Subtleties of fastening rafter legs

Fastening the truss system to brick, foam concrete, aerated concrete walls is made through the Mauerlat, which in turn is fixed with anchors. Between the Mauerlat, which is wooden frame, and with walls made of these materials, a waterproofing layer of roofing material, waterproofing, etc. is mandatory laid.

The top of the brick walls is sometimes specially laid out so that something like a low parapet is obtained along the outer perimeter. So it is necessary that the Mauerlat placed inside the parapet and the walls do not burst the rafter legs.

Roof frame rafters wooden houses rest on the upper crown or on the ceiling beams. The connection in all cases is made by cutting and duplicated with nails, bolts, metal or wooden plates.

How to do without furious calculations?

It is highly desirable that the cross section and linear dimensions of the wooden beams be determined by the project. The designer will give clear calculation justifications for the geometric parameters of the board or beam, taking into account the entire range of loads and weather conditions. If available home master there is no design development, his path lies on the construction site of a house with a similar roof structure.

You can ignore the number of storeys of the building under construction. It is easier and more correct to find out the required dimensions from the foreman than to find them out from the owners of a shaky unauthorized construction. After all, the foreman is in the hands of documentation with a clear calculation of the loads per 1 m² of roof in a particular region.

The installation step of the rafters determines the type and weight of the roofing. The heavier it is, the smaller the distance between the rafter legs should be. For laying clay tiles, for example, the optimal distance between the rafters will be 0.6-0.7 m, and for the installation of metal tiles and profiled sheets, 1.5-2.0 m is acceptable. However, even if the step required for the correct installation of the roof is exceeded, there is a way out . This is a reinforcing counter-lattice device. True, it will increase both the weight of the roof and the construction budget. Therefore, it is better to deal with the step of the rafters before the construction of the rafter system.

Craftsmen calculate the pitch of the rafters according to design features buildings, tritely dividing the length of the slope into equal distances. For insulated roofs, the step between the rafters is selected based on the width of the thermal insulation boards.

Rafter structures of layered type

Rafter structures of the layered type are much simpler in execution than their hanging counterparts. A justified plus of the layered scheme is to provide full ventilation, which is directly related to the longevity of the service.

Distinctive design features:

Mandatory presence of support under the ridge heel of the rafter leg. The role of a support can be played by a run - wooden beam, based on racks or on the inner wall of the building, or the upper end of an adjacent rafter.
The use of Mauerlat for the construction of a truss structure on walls made of brick or artificial stone.
The use of additional runs and racks where the rafter legs, due to the large size of the roof, require additional support points.

The minus of the scheme is the presence structural elements affecting the layout of the internal space of the operated attic. If the attic is cold and the organization of useful premises is not supposed to be in it, then the layered construction of the truss system for the installation of a gable roof should be preferred.

A typical sequence of work on the construction of a layered truss structure:

First of all, we measure the height of the building, the diagonals and the horizontalness of the upper cut of the skeleton. When identifying vertical deviations of brick and concrete walls, we eliminate them with a cement-sand screed. Exceeding the heights of the log house we squeeze. By placing chips under the Mauerlat, vertical flaws can be dealt with if their magnitude is insignificant.
The floor surface for laying the bed must also be leveled. He, the Mauerlat and the run must be clearly horizontal, but the location of the listed elements in the same plane is not necessary.
We process all wooden parts of the structure before installation with fire retardants and antiseptic preparations.
on concrete and brick walls we lay waterproofing for the installation of a Mauerlat.
We lay the Mauerlat beam on the walls, measure its diagonals. If necessary, we slightly move the bars and turn the corners, trying to achieve the perfect geometry. Align the frame horizontally if necessary.
We mount the Mauerlat frame. The splicing of the beams into a single frame is carried out by means of oblique cuts, the joints are duplicated with bolts.
We fix the position of the Mauerlat. Fasteners are made either with brackets to wooden plugs laid in the wall ahead of time, or with anchor bolts.
We mark the position of the bed. Its axis should recede from the Mauerlat bars at equal distances on each side. If the run will be based only on racks without lying down, the marking procedure is carried out only for these columns.
We install the bed on a two-layer waterproofing. We fasten it to the base with anchor bolts, with inner wall connect with wire twists or staples.
We mark the installation points of the rafter legs.
We cut out racks according to uniform sizes, because our bed is set to the horizon. The height of the racks must take into account the dimensions of the section of the run and the bed.
Installing racks. If provided by the project, we fix them with spacers.
We lay the run on the racks. We check the geometry again, then install the brackets, metal plates, wooden mounting plates.
We install a trial rafter board, mark the places of trimming on it. If the Mauerlat is set strictly to the horizon, there is no need to adjust the roof rafters in fact. The first board can be used as a template for making the rest.
We mark the installation points of the rafters. Folk craftsmen for marking usually prepare a pair of slats, the length of which is equal to the gap between the rafters.
According to the markup, we install the rafter legs and fasten them first at the bottom to the Mauerlat, then at the top to the run to each other. Every second rafter is screwed to the Mauerlat with a wire bundle. In wooden houses, the rafters are screwed to the second crown from the top row.

If the rafter system is done flawlessly, the layered boards are mounted in random order. If there is no confidence in the ideal structure, then the extreme pairs of rafters are installed first. A control twine or fishing line is stretched between them, according to which the position of the newly installed rafters is adjusted.

The installation of the truss structure is completed by installing the filly, if the length of the rafter legs does not allow the formation of an overhang of the required length. By the way, for wooden buildings, the overhang should “go beyond” the contour of the building by 50 cm. If the organization of the visor is planned, separate mini-rafters are installed under it.

Hanging truss systems

The hanging type of truss systems is a triangle. The two upper sides of the triangle are folded by a pair of rafters, and the puff connecting the lower heels serves as the base. The use of tightening allows you to neutralize the effect of the spread, therefore, only the weight of the crate, the roof, plus, depending on the season, the weight of precipitation, acts on walls with hanging truss structures.

The specifics of hanging truss systems

Characteristic features of hanging type truss structures:

Mandatory presence of a puff, made most often of wood, less often of metal.
The ability to refuse the use of Mauerlat. A frame made of timber will be successfully replaced by a board laid on a two-layer waterproofing.
Installation on the walls of ready-made closed triangles - roof trusses.

The advantages of the hanging scheme include the space under the roof free from racks, which allows you to organize an attic without pillars and partitions. There are disadvantages. The first of these is the limitation on the steepness of the slopes: their slope angle can be at least 1/6 of the span of a triangular truss, steeper roofs are strongly recommended. The second disadvantage is the need for thorough calculations for the competent device of cornice nodes.

Among other things, the angle of the truss truss will have to be set with jewelry accuracy, because. the axes of the connected components of the hanging truss system must intersect at a point, the projection of which must fall on the central axis of the Mauerlat or the lining board replacing it.

Subtleties of long-span hanging systems

Puff - the longest element of the hanging rafter structure. Over time, it, as is typical of all lumber, deforms and sags under the influence of its own weight. Owners of houses with spans of 3-5m are not too concerned about this circumstance, but owners of buildings with spans of 6 meters or more should think about installing additional parts that exclude geometric changes in tightening.

To prevent sagging in the installation scheme of the truss system for a large-span gable roof, there is a very significant component. This is a pendant called a grandmother. Most often, it is a bar attached with wooden surfs to the top of the truss truss. You should not confuse the headstock with the racks, because. its lower part should not come into contact with the puff at all. And the installation of racks as supports in hanging systems is not used.

The bottom line is that the headstock, as it were, hangs on a ridge knot, and a puff is already attached to it with the help of bolts or nailed wooden plates. Threaded or collet type clamps are used to correct slack.

Adjustment of the tightening position can be arranged in the zone of the ridge knot, and the headstock can be rigidly connected to it with a notch. Instead of a bar on non-residential attics reinforcement can be used to make the described tightening element. It is also recommended to arrange a headstock or suspension where the puff is assembled from two bars to support the connection area.

In an improved hanging system of this type, the headstock is complemented by strut beams. The stress forces in the resulting rhombus are extinguished spontaneously due to the competent arrangement of the vector loads acting on the system. As a result, the truss system pleases with stability with a slight and not too expensive upgrade.

Hanging type for attics

In order to increase the usable space, the tightening of the rafter triangles for the attic is moved closer to the ridge. A perfectly reasonable move has additional advantages: it allows you to use puffs as the basis for filing the ceiling. It is attached to the rafters by cutting with a semi-frying pan with a duplication of a bolt. It is protected from sagging by installing a short headstock.

A noticeable drawback of the attic hanging structure is the need for accurate calculations. It is too difficult to calculate it on your own, it is better to use a ready-made project.

Which design is more cost effective?

Cost is an important argument for an independent builder. Naturally, the price of construction for both types of truss systems cannot be the same, because:

In the construction of a layered structure for the manufacture of rafter legs, a board or beam of small section is used. Because layered rafters have two reliable supports under them, the requirements for their power are lower than in the hanging version.
In the construction of a hanging structure, the rafters are made of thick timber. For the manufacture of puffs, a material similar in cross section is required. Even taking into account the rejection of the Mauerlat, the consumption will be significantly higher.

Saving on the grade of material will not work. For the bearing elements of both systems: rafters, purlins, beds, Mauerlat, attendants, racks, lumber of the 2nd grade is needed. For crossbars and puffs working in tension, you will need the 1st grade. In the manufacture of less responsible wooden slips, the 3rd grade can be used. Without counting, we can say that in the construction of hanging systems, expensive material is used to a greater extent.

Hanging trusses are harvested on open area next to the object, then transported assembled upstairs. To lift weighty triangular arches from a bar, you will need equipment, for which you will have to pay rent. And the project for complex nodes of the hanging version is also worth something.

There are actually many more methods for constructing truss systems for roofs with two slopes. We have described only the basic varieties that are actually applicable for small country houses and buildings without architectural ideas. However, the information provided is sufficient to cope with the construction of a simple truss structure.

Do-it-yourself gable roof truss system: device, design, installation

In order for the truss system of a gable roof to be built competently and firmly with your own hands, you need information about the rules and principles of the device, fastening and

Construction of houses

During construction one-story houses the roof with two slopes is very popular. This is due to the speed of construction of the structure. In this parameter, only a single-pitched roof can compete with a gable roof. The device has a double slope rafter roof not too complicated. And you will successfully master this work on your own.

The design of the gable roof truss system

The gable roof consists of two inclined surfaces that have a rectangular shape. Thanks to this, precipitation, which is represented by rain and melt water, flows off the roof in a natural way. The gable roof has enough complex structure. It consists of such structural units: Mauerlat, rafter system, filly, ridge, roof overhang, bed, struts, puffs, crate and racks:

Mauerlat. This element performs the functions of transferring and distributing the load created by the rafter system on the load-bearing walls of the house. For the manufacture of Mauerlat, a bar is used, which has square section- from 100 to 100 to 150 to 150 mm. It is better to use softwood. The beam is placed around the perimeter of the building and fixed to the outer walls. For fastening use special rods or anchors.
Rafter leg. Rafters form the main frame of any roof. In the case of a gable roof, they form a triangle. The rafters are responsible for the uniform transfer of loads to the Mauerlat. First of all, those that arise from precipitation, wind and the weight of the roof itself. For the manufacture of rafters, boards are used that have a section of 100 by 150 or 50 by 150 mm. Choose a rafter pitch of about 60-120 cm, depending on the type of roofing material. When using a heavy coating, place the rafter legs more often.
Skate. This element connects two slopes at the top of the roof. The ridge is formed after connecting all the rafter legs.
Filly. They act as a continuation of the rafters and form the overhang of the gable roof. It is customary to install fillies if the rafter legs are very short and do not allow an overhang to form. To make this structural unit, take a board that has a smaller section than the rafter. The use of fillies facilitates the construction of the truss system, as it allows the use of short rafters.
Eaves. This part of the design of the gable roof truss system is responsible for draining water from the walls during rain and at the same time preventing them from getting wet and quickly destroyed. The overhang protrudes from the wall, as a rule, by 400 mm.
Sill. It is located on the inner wall and serves to evenly distribute the load from the roof racks. For the manufacture of bedding, a beam is used, which has a section of 150 by 150 or 100 by 100 mm.
Racks. These vertical elements are responsible for transferring the load from the ridge to the interior walls. To create this element, prepare a beam that has a square section of 150 by 150 or 100 by 100 mm.
Struts. They are needed to transfer loads from the rafters to the load-bearing walls. Struts and puffs form a solid structure called a truss. Such a device is designed to withstand loads at large spans.
Puff. This structural unit, together with the rafters, forms a triangle. It does not allow the rafters to part in different directions.
Crate. This design consists of boards and bars. They are attached perpendicular to the rafters. Sheathing is necessary to evenly distribute the weight of the roof covering and the loads created by weather phenomena on the rafters. In addition, the crate is required to fasten the rafters together. When arranging a soft roof to create a crate, you should not use boards and bars, but moisture-resistant plywood.

Varieties of gable roof truss system

There are gable truss systems with hanging and layered rafters. Ideally, the design contains a combination of them. It is customary to install hanging-type rafters if the outer walls are located at a distance of less than 10 m. Also, there should no longer be walls between them that divide the space of a residential building. The design with hanging rafters creates a bursting force transmitted to the walls. It can be reduced if you arrange a puff made of wood or metal and place it at the base of the rafters.

The rafters and tightening form a rigid geometric figure- triangle. It is not able to deform under loads that are in any direction. The puff will be stronger and more powerful if it is placed higher. The floor beams act as puffs. Thanks to their use, the hanging rafter system of a gable roof acts as the basis for the arrangement attic floor.

Laminated rafters in their design have a support beam, which is located in the middle. It is responsible for transferring the weight of the entire roof to the intermediate column or middle wall located between the outer walls. It is recommended to install rafters if the outer walls are placed more than 10 m apart. If there are columns instead of internal walls, you can alternate between rafters and hanging rafters.

Do-it-yourself gable truss system

The roof must be strong to withstand various loads - precipitation, gusts of wind, the weight of a person and the roofing itself, but at the same time light, so as not to put a lot of pressure on the walls of the house. A properly arranged gable rafter roof evenly distributes the load on all load-bearing walls.

Calculation of a gable roof

The choice of a gable roof slope will depend on the material you have chosen for laying on the roof and architectural requirements:

When building a gable roof, remember that it must slope at an angle of more than 5 degrees. It happens that the slope of the roof reaches 90 °.
For areas with heavy rainfall, and when roofing does not fit tightly, make steep slopes. In this situation, the angle should be 35-40 ° so that precipitation does not linger on the roof. But such an angle does not allow building a living space in the attic. The output will be a broken roof structure. It will have a flat upper part, and on the lower part there will be a sharp slope.
In regions with strong gusts of wind, sloping roofs are equipped. If constant winds prevail in the area, then make a slope of 15-20 ° for high-quality protection of the roofing.
It is best to choose the middle option. Equip a gable roof that is not too steep. But also the slope should not be very gentle.
When choosing a large angle of the roof, its windage increases, and, accordingly, the price of the gable roof truss system and the crate. After all, such a slope entails an increase in the area of \u200b\u200bthe roof and, accordingly, the number required material- construction and roofing.

When buying materials for the construction of a gable roof, it is useful to calculate its area:

Find the area of one slope of the structure, and then double the result.
Ideally, a slope is an inclined rectangle that is placed along a long load-bearing wall. To determine the area of a slope, multiply its length by its width.
The length of the slope is equal to the length of the wall. In addition, the length of the ledge of the roof above the gable is added to the length. Remember that the protrusions are present on both sides.
The width of the slope is the length of the rafter leg. To it is added the length of the ledge of the roof above the load-bearing wall.

In order to properly design the structure, it is recommended to carry out an accurate calculation of the gable roof truss system, including determining the loads and characteristics of the rafters:

When erecting a roof for a standard building that has one floor, the design load on the roof will consist of two values. The first of them is the weight of the roof, the second is the load from external factors: precipitation and wind.
Calculate the weight of the roof by adding up the weight of each layer of the "pie" - heat-insulating, vapor barrier and waterproofing materials, truss system, battens and directly roofing material. Calculate the weight per 1 m2.
Increase the result by 10%. You can also take into account the correction factor. In our case, K=1.1.
If you plan to change the design of the roof over time and increase the angle of its inclination, then include a margin of safety in the calculation. Take more immediately high performance loads than those that you received at the time of calculation. It is recommended to build on the value, which is 50 kg per 1 m2.
When calculating the load exerted by atmospheric phenomena, take into account the climatic features of the area where the building is located. In this calculation, take into account the slope of the slope. If the gable roof forms an angle of 25 degrees, then take the snow load equal to 1.
If the roof is equipped with a greater slope - up to 60 degrees, the correction factor reaches 1.25. Snow load for an angle greater than 60 degrees is not taken into account.
The rafters transfer the entire load from the created structure to the load-bearing walls. Therefore, their parameters must also be taken appropriately. Select the section and length of the rafter leg, depending on the current load on the roof and the angle of the slope. Increase the values obtained by 50% to ensure a high margin of safety.

Mauerlat installation methods

The construction of any roof begins with the installation of a Mauerlat:

If logs or timber were used to build the walls, then the upper timber will act as a Mauerlat, as shown in the photo of the gable roof truss system.
If you used bricks to build walls, then brick the metal rods into the masonry. They must have a cut thread for attaching the Mauerlat. Install rods every 1-1.5 m. Choose rods with a diameter of at least 10 mm. Lay waterproofing between masonry and Mauerlat.
For walls made of ceramic or foam concrete blocks, pour concrete on top. Be sure to make the layer reinforced. It should have a height of approximately 200-300 mm. Be sure to attach metal rods that are threaded to the reinforcement.
For Mauerlat, use a beam that has a section of 15 by 15 cm. It will act as a kind of foundation for the truss system.
Lay the Mauerlat on the top edge of the wall. Depending on its design, the Mauerlat can be laid along the outer and inner edges. Do not place it close to the very edge, as otherwise it may be torn off by the wind.
Mauerlat is recommended to be placed on top of the waterproofing layer. To connect all the parts into one whole, use bolts and metal plates.
To avoid sagging, make a lattice of racks, struts and a crossbar. To do this, take boards measuring 25x150 mm. The angle between the strut and the leg of the rafter should be as straight as possible.
If using a rafter leg that is too long, install another support. She must lean on the bed. Each element is associated with two adjacent ones. As a result, a stable structure is created around the entire perimeter of the roof.

Rafter leg attachment

The best option for a gable roof truss system is a combination of sloping and hanging rafters. This design allows you to create a reliable gable roof and reduce the cost of building materials. Consider the following recommendations when working:

Use only the highest quality wood as a material. Beams that have cracks and knots should not be used.
Rafters have standard dimensions - 50x150x6000 mm. When the beams are longer than 6 m, it is recommended to increase the width of the board so that the beams do not break under their own weight. Take boards 180 mm wide.
First, make a template for the rafter leg. Attach the board to the floor beam and the end of the ridge beam. Having outlined two lines, saw off a board along them. The template is ready.
Cut the rafters according to this pattern. After that, do the top washed down on them.
Take the resulting workpiece, bring it to the floor beam to mark the lower cut in place.
Install all rafters. At the same time, remember that after installing one leg, you must immediately install the opposite one. So you will quickly remove the lateral loads on the ridge beam.
If the slope is too long, then standard boards will not be enough to make a rafter leg. In this case, you can splice two boards together. To do this, sew on them a piece of wood of a similar section. It should have a length of 1.5 - 2 meters. According to the diagram of the gable roof truss system, the joint should always be at the bottom. Under it, install an additional rack.
Attach the rafter leg to the ridge beam with nails. Use self-tapping screws to fasten the rafters to the floor beam. Metal mounting plates are also suitable. In addition, a few nails are added.
If you are building a structure exclusively from hanging rafters, then skip the next step. When erecting a structure with layered rafters, you need to think about the supports that are installed on their floor. To reduce the deflection of the rafters, correctly calculate the location of such supports.
If you're building a gabled mansard roof, the intermediate studs will form the frame for the side walls.
When performing this work, maintain a certain step of the beams. Set its size at the design stage.
After installing the rafters, attach the ridge. It is located on their upper edge. For fastening use metal corners or staples. Bolts are the most popular.

Giving structure rigidity

After installing the gable roof truss system, strengthen it using the technology below:

For smaller buildings, such as saunas, cottages, utility buildings, and roofs with a simple hanging rafter system, connect each pair of rafters from below with a tightening and from above using a crossbar.
For large buildings that are light at the same time, provide a lightweight roof. The walls must support it.
If the house has a width of 6-8 m, then the structure should be tightened. Install in the middle of the support. Such racks are called grandmas. Place them at each pair of rafter legs.
If the span of the walls reaches 10 meters, then reinforcing beams will be needed. The struts act as an additional support for the rafter legs for tightening. They are attached to each rafter - closer to the ridge or in the middle of the rafter leg. Fasten them to the bottom end of the headstock and to each other as shown in the gable roof truss video.
In a situation with long roofs, gable beams should be relieved. This is done by installing braces. The upper end should rest against the corner of the gable. The lower one is mounted on the central floor beam. For fasteners, use a beam that has a large cross section. So you can prevent them from breaking if there are strong gusts of wind.
In areas where winds predominate, the rafters must be resistant to such influences. Strengthen them by installing diagonal ties. Boards are nailed from the bottom of one rafter to the middle of the next.
For greater rigidity, when creating the most critical fasteners, it is better not to use nails. Use pads and metal fasteners for this. Nails will not be able to provide high-quality fastening, since the wood can dry out after some time.

Lathing of the truss system

The final stage of the construction of the gable roof truss system is the creation of the crate. It is on it that you will lay the roofing. Carry out the work in the following sequence:

Select a dry timber for the crate. It should not have cracks or knots. Nail the bars on the bottom. Attach two boards near the ridge so that there are no gaps. The lathing must withstand the weight of the top roofing material and not sag under the weight of the workers.
If you will equip a soft roof, make two layers of sheathing. One is sparse, the other is solid. The same applies to roll roofing. To begin with, parallel to the ridge beam, place boards that are 25 mm thick and no more than 140 mm wide. A small gap is allowed - no more than 1 cm. Lay a continuous layer on top. To do this, it is better to use roofing plywood, slats or boards of small thickness. After that, check that there are no errors left on the crate - bumps and knots. Also check that the nail heads are not sticking out.
Lay one layer of timber under the metal tile. It should have a section of 50 by 60 mm. Do the same when using slate or steel roofing sheets. Maintain a step between the timber, depending on the roofing you choose - from 10 to 50 cm. Hammer nails closer to the edges of the board, and not in the middle. Drive hats deep. So they will not be able to damage the roof later. If you are making a crate for a metal tile, then remember that the connection of the timber at the same level should fall on the rafters.

When you have installed and strengthened the gable roof truss system, you can start installing the roofing pie. Place a thermal insulation material between the rafters, a layer of vapor barrier and waterproofing. When using insulation in slabs, calculate in advance the pitch of the rafters for its installation. At the final stage, fasten the roofing material.

The device of the gable roof truss system, Building Portal

Construction of houses In the construction of one-story houses, a roof with two slopes is very popular. This is due to the speed of construction of the structure. For this setting,

The gable truss system is chosen by many owners of residential buildings. This is due to its high practicality and ease of creation. If you carefully study the structure of the gable roof truss system, then the process of its formation can be done by hand. The resulting design is highly reliable and durable, and also guarantees excellent protection of the building from cold and precipitation.

Main elements of the system

The design of the gable roof truss system is considered simple. It consists of a variety of elements made of wooden elements with different lengths, configurations and sections. The main nodes include:

Mauerlat. Represented by a beam with a section in the form of a square. To create it, coniferous wood is usually used. Its dimensions vary from 10 to 15 cm. It is laid along all the load-bearing walls of the building. It is fixed to them with the help of anchors or special rods. If you make and attach it correctly, then it will evenly distribute the load from the rafter legs along all the walls of the structure.
Rafter legs. They are created from a bar with dimensions of 15x10 or 15x5 cm in section. With their proper connection, a roof contour is formed that has the shape of a triangle. It must be strong and reliable in order to withstand heavy loads from rain and wind. Rafter legs must be fixed at a distance of about 1 m from each other.
Sill. It is created from a square wooden beam, the cross section of which is . It is laid horizontally on a load-bearing wall inside the building. Due to it, the load coming from the roof racks is evenly distributed.
Puff. This element is used if a hanging structure is selected. It is installed on top of the resulting triangle of rafter legs, which ensures its stability.
Racks. To create them, a square beam is used. They are in a vertical position. They bear the load from the ridge, after which it is transferred to the load-bearing wall inside the building.
Struts. The installation of these elements is necessary in order to obtain a special transmission element located between the rafter legs and various load-bearing parts. Due to their reliable connection with a tightening, the creation of a strong structure is guaranteed.
Crate. It is assembled from bars or boards. Installed perpendicular to the legs of the rafters. It provides the transfer of gravity from the roof of the roof to the legs of the rafters. It is advisable to use to create this element edged boards. If you plan to create a coating on the roof of soft roofing materials, for example, shingles, then by all means the crate must be continuous.
Skate. It is represented by the topmost element of the entire roof. Due to it, its two slopes are connected. Its assembly is carried out by connecting the legs of the rafters at the top of the roof. It must be placed in a horizontal position.
Eaves. It protrudes from each wall of the building by about 40 cm. Its installation is due to the need to protect the walls from water flows as a result of precipitation.
Filly. Provides the ability to create a roof overhang. They are used exclusively in a situation where short rafter legs are used, so they are lengthened by fillies.

Important! The step between the legs of the rafters is chosen in accordance with the severity of the roof, since the more weighty it is, the smaller this gap should be.

Thus, the installation of a gable roof truss system is considered quite simple, so it is not difficult to make this design with your own hands.

Types of structures

The rules and features of the installation of this design depend on the selected variety.

Types of gable roof truss system:

All options have their own characteristics, so their characteristics are preliminarily evaluated. If you plan to install a gable roof truss system with your own hands, then a simple symmetrical design is chosen.

Important! The basis for obtaining the ideal result is competent calculations, and if they are incorrect, then the roof will not be reliable and durable, and it will also be dangerous to live in such a house.

How to choose the material to create the system?

When choosing a material, the following rules are taken into account:

rafters are created exclusively from high-quality wood, on which there are no rotten areas, damage, knots or other shortcomings;
edged boards are purchased to form the crate;
all wood should be well treated with antiseptics and fire retardants.

Important! Knots are allowed, but their length cannot be more than 1/3 of the thickness of the timber used.

Calculation rules

To make the gable roof truss system reliable and of high quality, a lot of attention is paid to competent calculations. They should affect all elements of the future design:

Load calculation. Any system is affected by two types of load. The constants will regularly act on the structure, and this includes the weight from the roofing of the roof, battens, thermal insulation material, waterproofing, extensions and finishing materials used for the attic. Typically, this load is 40 kg / m. sq. Variable loads can have different strengths, as they include wind, snow exposure and precipitation intensity. To calculate the load, the wind load of a particular region is multiplied by a special correction factor.
Determining the angle of inclination. A roof with two slopes may have different angle slope, and it is determined by the roofing material used. If mounted soft roof, then for it a slope is selected in the range from 5 to 20 degrees, or metal tiles vary from 20 to 45 degrees.
Snow load calculation. In winter, the roof can accumulate a large number of snow. In order to avoid any problems with the structure, the frame must withstand these loads. The calculation requires the weight of the snow to be multiplied by the correction factor.
Definition . The gap between these elements is usually chosen in the range from 60 to 100 cm, and the final choice depends on the roof and the weight of the roof.
Definition . To do this, it is recommended to use the standard Pythagorean theorem.
Determination of the section of the rafters. This parameter is influenced by several important factors: roof loads, the type of materials used, the length of the rafter legs, as well as the step between them.

Important! When calculating loads, the possibility of a storm or tornado is additionally taken into account, since if the house is located in a region where such loads can appear, then a margin of safety is made for the roof, read more:.

Types of rafters

Before direct work on creating a gable roof with your own hands, you should make a special plan, which will contain a drawing and layout of the entire structure. This takes into account which rafters will be used, since the following types can be used:

. Suitable for small buildings. Their installation consists in fixing the legs to the bearing wall of the structure, as well as to the ridge run. A feature of the use of these elements is that a bursting force acts on the rafter legs, and puffs are used to reduce this effect. They can be made from wood or metal.
Layered. Suitable for roofs of any shape and size. The layered design is used in conjunction with racks and lying down. The bed is laid parallel to the fixed Mauerlat, so a certain part of the load is transferred to it. This allows you to tilt the legs of the rafters, which are additionally supported by the rack, to each other.
Combined. They are used when using unusual gable roof configurations.

After determining the main design parameters, the calculation of the required amount of material begins. Then you can proceed to the direct creation of the truss system.

Assembly of the structure

The do-it-yourself truss system of a gable roof is created only after the preliminary formation of drawings and plans. The scheme of future contraction should be clear and correctly calculated. For this, it is recommended to use special computer programs.

Important! In the presence of Money it is allowed to contact specialized construction companies for the correct calculation.

Installation of a gable roof truss system is divided into successive stages:

to the walls of the building. Its installation is carried out along their entire length. If the house is made of logs, then the Mauerlat acts as its upper crown. If the building is selected cellular concrete or brick, then it is mounted on top of the load-bearing wall along its entire length. It is required to splice the Mauerlat, for which the bars are sawn at a right angle and connected with bolts. It can be fastened with an offset to the side of the wall or in its center. Laying is carried out on a waterproofing layer, for which roofing material is usually used.
Creation of roof trusses. To do this, it is allowed to install bars on the roof or form a structure on the ground, after which it rises to the roof. The second option is often chosen, since it is difficult to perform work on the roof of the house. But to raise the structure made, you will have to use special equipment. Before connecting the legs of the rafters, the correctness of their size and location is checked.
. The formed pairs rise to the roof, after which they are laid on the Mauerlat. For the competent performance of the work, special cuts are made from the bottom of the legs. The process begins with the ends of the roof, located opposite to each other. To obtain a perfect result, temporary fasteners are used when installing the elements. A rope is pulled between the fixed pairs, making the installation of subsequent elements simplified. All rafter legs are mounted, and the correct step between them is checked. Next, a special skate support is installed. All additional elements used in the rafter system are fixed by cutting and brackets. It is allowed to lengthen the rafter legs if necessary.
Skate installation. It is created with the help of a competent connection on top of all rafter legs. Different methods are used for its formation, and it is allowed to use a support bar for this or you can work without it. If a beam is used, then it is allowed to put a skate on it or use the cutting method.
The rafter system is considered to be done, but in order for it to be strong and reliable, it is necessary to thoroughly fix all the elements, therefore, all temporary fasteners are eliminated, in place of which high-quality products are used to fix all parts of the system.
Lathing installation. This design is intended for easy movement on the roof, and also serves as the basis for laying the roof. Its type and parameters depend on the chosen roof. A solid crate is created if a soft roof is selected. has a distance between the boards within 35 cm. For or slate, this parameter is 44 cm.

In previous articles that described the roof structure, we already said that the hanging rafters rest on the Mauerlat with their lower end, and the upper ends of adjacent rafters abut (either directly or through a ridge board) against each other. In the most simplified version, this is shown in Fig. 1:

Picture 1

I think it is obvious to everyone that with such an arrangement, there are bursting loads on the walls. To reduce them, puffs are added to the truss truss. But let's talk about everything in order.

As an example, let's take a house with a semi-attic in the Volgograd region. The sum of snow and wind loads is 155 kg/m 2 . The dimensions of the house box are 8x10 meters. The thickness of the walls is 50 cm. The angle of inclination of the slopes is 40 ° (see Fig. 2):

Figure 2

STEP 1: We install . In this design, in addition to the usual loads, bursting forces will act on it, tending to move it off the wall. For more reliable fastening, you can add more metal mounting plates to the anchor bolts (or studs) (see Fig. 3). The plates can be fixed to the wall, for example, with frame anchors, and to the Mauerlat, you can use nails, self-tapping screws, and capercaillie.

Figure 3

STEP 2: We determine the required section of the rafters. We make the calculation in the "Arch" tab (see Fig. 4):

Figure 4

The cross section of the rafters is taken 50x200 mm in increments of 60 cm.

A question may immediately arise here. Where do we get the distance from the ridge to the puff (crossbar). We have it equal to 2 meters. Earlier on the site, we already said that before proceeding with the construction of the roof, we need to make a drawing of it on paper, be sure to scale (in all proportions). If you know how, you can draw on the computer. Further, according to this drawing, we determine all the dimensions and angles of interest to us.

Puffs are installed between hanging rafters to reduce bursting loads on the walls. The lower the puff, the more useful it is. Those. the less bursting load falls on the walls. But since in our example, the puffs still play the role of the ceiling beams of the attic floor, we determine the height of their location based on the height of the ceilings we need. I took this height of 2.5 meters (see Fig. 5):

Figure 5

STEP 3: We make a template for the lower rafter cut. To do this, we take a piece of board of the section we need about a meter long, apply it to the Mauerlat at our angle of inclination of the slopes of 40 ° (orient yourself along the pediment) and make the markup, as shown in Figure 6:

Figure 6

The vertical and horizontal lines we need (shown in blue) are drawn using a level. Depth washed down 5 cm.

So let's make a template.

STEP 4: We install a ridge board, through which all the rafters will be interconnected. First you need to outline the place of its installation.

We take the template made earlier and apply it to the Mauerlat. We are interested in the size shown in Figure 7 (here it is 18 cm):

Figure 7

Let's call the lower point on the Mauerlat point "A".

We transfer the resulting size to the top of the pediment, make markings in accordance with Figure 8:

Figure 8

Let's designate the lower right corner as point "B". Now we can measure the distance from the attic floor to point B (the length of the temporary posts).

We install strictly vertically temporary racks from a 50x200 board and put a ridge board of the same section on them. Under the racks for their fixation, you can put a board fixed with simple dowel nails to the floor slabs (see Fig. 9). It is not necessary to fasten strongly, then we will remove it. The distance between the racks is not more than 3 meters.

Figure 9

We fasten the ridge board to the gables with metal brackets. The stability of the racks is provided by jibs.

Perhaps you could see somewhere how hanging rafters are installed without a ridge board (see picture on the left). This method is very familiar to me, we used to do this too.

But when we tried the option with a ridge board, we settled on it. Despite the fact that it takes some time to install the racks and the ridge board, the subsequent installation of the rafters is much more convenient and faster. In the end, you win in time. In addition, the design is more stable and more geometrically even.

STEP 5: We manufacture and install rafters.

We do the rafter like this: we take a board of the desired length, apply a template to one end, mark it out and make the bottom washed down. Then we measure the distance between points "A" and "B" with a tape measure (see Fig. 7-8). We transfer this size to our workpiece and make the top washed down. The angle we need for the top notch is on our template (see Fig. 10). We have it equal to 90 ° + 40 ° = 130 °

Figure 10

Thus, we put all the rafters (see Fig. 11)

Figure 11

The connection of the rafters with the Mauerlat here does not look the same as it was, for example, I think you have already understood that this is due to the presence of bursting loads, which were not in that version. However, in future articles you will see that this option is just one of the possible, and not the only correct one. We will use more familiar to us washed down. The main thing is to securely fasten the rafters to the Mauerlat.

At the top, the rafters will protrude beyond the ridge board. You can drive small bars between them, or you can leave it as is. This, in principle, does not play any role (see Fig. 12):

Figure 12

We fasten the rafters to the ridge with nails or self-tapping screws. It is not necessary to install any additional fasteners here. In general, in this design, thanks to the lower gash, the rafters are obtained, as it were, sandwiched between the Mauerlat and the ridge board.

STEP 6: Installing braces.

We make them from boards of the same section as the rafters. There is no need to make any cuts and cuts here. We make puffs superimposed on the rafters. We fasten them with several nails and tighten them with a threaded stud with a diameter of 12-14 mm (see Fig. 13):

Figure 13

Thus, we install all the puffs and remove our temporary racks on which the ridge board was placed:

Figure 14

Now you can guess the purpose of the small windows in the upper part of the pediment. Through them, ventilation of the insulation will be carried out, which will lie on the ceiling of the half-attic floor (between puffs).

STEP 7: We attach the filly of the cornice overhang to the lower ends of the rafters (see Fig. 15). We make them from boards with a section of 50x100 mm. We make the length of the filly such that we get a cornice overhang of the width we need (40-50 cm), and that it overlaps the rafter by at least 50 cm. We fasten the filly with several nails and tighten it with 2 threaded studs. In the middle part, for additional emphasis on the wall, you can fasten a small bar to the filly with nails or self-tapping screws.

Figure 15

Please note that at the junction of the filly of the overhang with the Mauerlat, we do not drink on it, because. this will reduce it and without that not a large cross section. Here we first make a small cut in the Mauerlat itself (see Fig. 16):

Figure 16

To make the cornice even, use a lace. First put the extreme fillies, then pull the lace between them and put all the rest. In Figure 17 the shoelace is shown in blue.

Figure 17

Step 8: The following steps are already known to us from previous articles. We put the fillies on the pediment and fasten the wind boards (see Fig. 18):

Figure 18

STEP 9: Now we can leave the cornices in the form in which they are.

Let's see another version of the eaves overhangs (see Fig. 19):

Figure 19

Such "earrings" are made from inch boards 10-15 cm wide. We fasten them with self-tapping screws.

Thus, now it remains for us to hem the siding belts to the bottom of the cornices; having fixed a protective film on the rafters, make a counter-lattice and a crate; cover the roof with roofing material. We have covered these steps in previous articles. I think it makes no sense to repeat here and when considering other roof structures in the future.

The roof is an important structure of the house. She completes the construction of the building frame, after which only the finishing remains. The most common execution scheme with two slopes. The gable roof is made by hand without much difficulty, you just need to understand the technology.

Roof structure

Before you start installing a gable roof, you need to figure out what it is. The design differs from all other gables. You can bring the following varieties of them, depending on the method of assembling the truss system:

shed - gables have the shape of a trapezoid or a right triangle;
gable is characterized by triangular gables;
four-slope (hip) has no vertical edges.

The main elements of the gable roof system are:

rafters;
Mauerlat;
crossbar;
struts;
racks;
contractions (screeds);
crate;
thrust bars and pads.

Rafters are the main supporting structures. When building with your own hands, it is important to choose their cross section correctly, otherwise an emergency situation may arise.

Preparing to start work

Before you make a gable roof, you will need to select materials. Installation begins with the choice of wood. To build with your own hands robust design resistant to external factors, you will need to follow these recommendations:

For construction, it is better to choose conifers of the first or second grade

it will be right to choose coniferous wood materials (spruce, pine, larch are more resistant to decay);
the assembly of the structure is carried out from wood of the first or second grade, the use of the third for critical elements is unacceptable;
it is better to choose those lumber that is produced in the northern regions, the more difficult the growing conditions of the tree, the denser its structure;
they try to choose the material that is cut down at the end of the cold period of the year (February-March).

load from snow cover (snow area);
weight of roofing;
rafter step;
span (distance between reference points);
insulation thickness.

A heat-insulating layer is required when designing a living space in the under-roof space of a house - an attic. Most often, do-it-yourself installation of mineral wool material is performed to improve thermal insulation characteristics. At the same time, it is important to provide a ventilation gap between the heat insulator and the roofing. The height of the rafter leg should not be less than the thickness of the insulation. To increase the clearance, such an element of the system as a counter-lattice is introduced - a bar that is nailed parallel to the rafter leg and increases its height.

The most convenient rafter pitch for a private house is the one that provides a clear distance of 0.58 m between them.

This allows you to correctly install mineral wool slabs without undercuts and additional elements. For such a step, the following recommendations for the cross section can be given, depending on the span:

span 3 m - rafter size 40x150 mm;
4 m - 50x150 mm;
5 m - 50x175 mm;
6 m - 50x200 mm.

It is important to know the following: load-bearing capacity and bending resistance are more affected by height than width. If necessary, increase the bearing capacity more effectively increase the height.
Another element whose cross section will need to be selected is the crate. The most optimal value will be a thickness of 32 mm. With increased load, the value is increased to 40 mm.

The remaining components of the truss system of the house are assigned constructively, based on what lumber is available. But at the same time, strength requirements should still be taken into account.

Immediately after purchasing the material, before the assembly of the system begins, you will need to process all the elements with special compounds with your own hands.

Gable, like any other roof of the house, needs the following types of protection:

antiseptic, produced without fail, allows you to prevent the processes of decay and the occurrence of mold and fungus (even if installation is not planned some time after the purchase of wood, processing is carried out immediately);
flame retardant, optional, but very important, increases the ability of the tree to resist fire, which increases the safety of the building.

Installation of the truss system at home

To build a roof at home with your own hands, you need to do all the work in a certain order. Installation of elements does not cause difficulties, but the quality of nodes and connections must be controlled. The most important areas are:

fastening the Mauerlat to the wall;
fastening rafters to the Mauerlat;
fastening the rafters to each other.

To properly build a roof with your own hands, the work should be done in the following order:

Mauerlat installation;
installation of rafters at a design angle;
fastening of the legs in the upper part;
unfastening of load-bearing structures with the help of racks, struts and contractions;
installation of counter-lattices, battens, waterproofing;
do-it-yourself insulation of the roofing system;
installation of the lower lathing, installation of roofing.

Mauerlat fastening to the wall

When installing with your own hands, it is important to understand where to put the Mauerlat. A bar with a section of 150x150 mm or 200x200 mm is installed on the inner edge of the outer walls. At the same time, it is important to ensure sufficient thermal insulation of such a site. The outer part of the fence in this area can be made of the same material as the walls.

In this case, laying is performed at an angle equal to the slope of the slopes. The second option is to fill the space with expanded clay concrete. These methods are relevant for stone houses (brick, foam concrete, expanded clay concrete, etc.). If you plan to build a frame or wooden house the upper trim or the crown of the wall will act as a Mauerlat.

There are several ways to get the job done:

Staple fastening. To do this, wooden blocks are installed in the penultimate row of masonry, to which the lower part of the brackets will be attached, and the upper part is wound into the Mauerlat. Wooden corks must be impregnated with an antiseptic.
Wire attachment. To perform this option, you will need to lay a wire 3-4 mm thick in the masonry walls or a monolithic belt, its length should be such as to wrap the beam and twist the wire rod.
Fastening with bolts or studs. The options are similar, but the first one provides more reliability. Fasteners are laid in a monolithic belt. After that, the beam is laid on studs or bolts. To make holes for them in the right places, lightly tap on the Mauerlat. The resulting recesses will be places for drilling holes. After their preparation, the beam is finally installed in the design position and tightened with nuts.

When building a house, it is also important to know how to build up the Mauerlat. Standard sizes lumber - 6 m, and the walls can be longer. To connect two elements along the length, you will need to perform a direct lock. To do this, cut out the lower part of one element, and the upper part of the other. Fastening is done with bolts. It is not recommended to cut at an angle in this case. With the help of a direct gash, corner joints are also made.

The choice of mounting method for the Mauerlat largely depends on the material of the walls, more precisely on its strength. For lightweight concrete, a mandatory event will be the pouring of a monolithic belt around the perimeter.

It is important to provide waterproofing between wood and stone material. For this, roofing material, linokrom or hydroisol are most often used.

There are two most common options for doing do-it-yourself work when building a house:

with a gash;
without drinking.

In both cases, the rafters are additionally fixed with metal corners on both sides. When using a system with a gash, you will need to process the timber at an angle corresponding to the slope of the roof of the house. When installing without a gash, it is necessary to prepare a support beam with your own hands, which will not allow the system element to move across the Mauerlat. As an additional fixation, nails are hammered and a wire is twisted from the leg to the wall (you can perform such an attachment through one leg).

2 types of fastening rafters to Mauerlat

How do-it-yourself gable rafters of the house will be installed, for detailed and visual information, it is recommended to familiarize yourself with the series “knots of wooden roofs of residential rural buildings”. This album contains a large number of options for fixing all the elements that will help you complete the installation without errors.

Among the wide variety of types of roofs, it has been the most popular for several centuries. The relative simplicity of the design, excellent stability, adaptability to different climatic conditions are weighty arguments, proven by many years of construction practice. The following information will be useful to those who will build the gable roof truss system with their own hands and to those who decide to use the services of professionals to understand and control the work.

Types of gable roofs

A gable roof, also called a gable roof, consists of two inclined rectangular planes - roof slopes, which are installed at a certain angle to the outer walls of the building. Due to the angle of inclination of the slopes, a natural runoff of natural precipitation (rain, melt water) is provided.

Roofs with uneven slope angles (i.e. the location of the ridge is not through the center of the building) and various lengths cornice overhangs are used if the customer wishes to express the architectural feature of his housing. Such a roof, in terms of design, looks quite original, but has the disadvantage of irrational use of the attic space.

A broken gable roof is applicable in cases where there is a need to use an attic space for an attic. In such a roof, the increased volume of the attic makes it easy to equip the attic, which is protected from moisture and insulated.

A gable symmetrical roof has an isosceles triangle at its base. The orthodox form and unpretentiousness during construction made it a favorite not only of professional builders, but also of beginners.

Half-hip roof - one of the varieties of gable roofs, which is distinguished by its original appearance and creates high-quality protection of the pediment. This type of roof is especially in demand in areas with high wind load.

The first thing you should pay attention to when organizing the construction of a gable roof is its angle of inclination. To a lesser extent, it depends on architectural features, but to a greater extent on the climatic features of the region in which the roof will be erected and on the type of roof being installed. Roofs with a steep angle of inclination are installed in regions that are subject to frequent rainfall. Areas with strong wind zones require the installation of gentle slopes to relieve the structure from wind loads.

The angle of inclination of the slopes can lie in the range from 5 to 90 °. A common option is a roof with a slope angle of 35-45 °. This option is the most economical, in terms of the consumption of building materials and even distribution of the load around the entire perimeter of the building. With such an angle of inclination, the attic space is made of a cold type and in the future it is not suitable for living in it.

If it is necessary to equip the attic space for a living room, then it is necessary to use a broken gable roof. In this case, the upper part of the roof will become more gentle, and the lower part will have a steep slope. The attic space will increase and it will be possible to use it for attic housing. For this type of slope, the design of the truss system will become more complicated compared to using a simple option.

Types of truss systems for gable roofs

The technology of the rafter system for a gable roof has differences in the use of support bases for rafters. There are hanging and layered systems of rafters. Accordingly, truss systems use hanging or layered rafters in their design. There is a third option - a hybrid, when both types are installed in the truss system.

Hanging rafters are used in structures with a distance between supports of no more than 6-6.5 meters.

Laminated rafters are installed in buildings with a load-bearing middle wall or with columnar supports inside.

The load-bearing structural elements in a gable roof are the truss system and the Mauerlat.

The rafter system includes such elements as: rafter legs, vertical racks, inclined struts, crossbars, spacers, ridge run. All these elements, connected into a single structure, form the truss system, as such.

The material from which the rafters and other structural elements are made can be made of wood, iron and reinforced concrete.

Before using the material, it is necessary to pay attention to the fact that the knots that have come across do not exceed one third of the thickness of the material in their length!

Mauerlat is a bar with a section from 100 × 100 mm to 200 × 200 mm, which is placed under the rafter leg or laid along the entire perimeter of the structure. Its purpose is to distribute a uniform load on the outer walls.

Mounting of the Mauerlat takes place on the upper wall edge. Installation takes place either along the axis of the wall, or with an offset to the outer or inner edge of the wall (but not more than 50 mm from the outer edge). Before installing the Mauerlat, a waterproofing material is placed under it, which, most often, is roofing material. The connection of the Mauerlat links must be strong and occurs with the help of direct locks.

The device of the truss system

The main types of roof structures:

rafter legs of opposite slopes are connected by horizontal puffs (for a house width of up to 6 m);
the ridge run is supported by vertical posts, additionally inclined struts are used (for houses up to 10 m wide with an empty attic, the design is designed for high loads);
horizontal girders resting on vertical racks act as additional points of support, the rafters are connected by puffs (for a house width of up to 15 m).

Rafter structures are made of timber with a cross section of at least 50 × 150 mm. The location of the crossbar is carried out at the level of the future ceiling of the attic.

If, when building a house with your own hands, it is possible to raise finished trusses to the installation site, it is recommended to make rafters on the ground using the first A-shaped frame element as a template.

Rafter legs are recommended to be made from a single bar, but if necessary, the bar can be spliced on both sides with nails or self-tapping screws. The pitch of the rafters can be calculated based on the dimensions of the sheet insulation. First of all, the extreme A-shaped elements are installed, on which the ridge run is attached, made of a 100 × 150 beam or a 50 × 150 board. The ridge run gives rigidity to the entire frame.

In order not to weaken the Mauerlat, the fastening slots are made in the rafters, as a result of which the rafter with the horizontal plane of the slot lies on the surface of the Mauerlat, and the protrusion rests against vertical plane Mauerlat. Fixation is carried out with three nails, two of which are driven on both sides of the rafter, and the third through its upper plane.

Exists various ways fixing rafters in the upper part of the gable roof, which you can do yourself:

The edges of each pair of rafters are cut in such a way that, when the cut planes are mated, the rafter legs form a given angle of inclination of the roof. Then the rafters are fastened together with wooden planks using nails, or metal plates with bolted connections. A nail with a length of at least 150 mm should be hammered into the upper plane of the rafters;
The rafters of different slopes are placed on the installed ridge run, while they must be cut so that the horizontal section is equal in width to half the thickness of the ridge beam. The rafters are fixed to each other with metal strips, which should be placed above the span (hanging connection, requires rigid fastening of the legs to the Mauerlat);
Overlapping - the simplest option, the rafters are tilted at the same angle and connected with studs or bolts using wide washers.

At the next stage, such types of elements as runs, racks, struts, etc. are mounted, if they are included in the selected frame scheme. During installation, it is important to control the verticality and horizontality of the structures. Mistakes made during the construction of the roof are almost impossible to correct.

Design features

The traditional, widespread option is symmetrical gable roofs with straight slopes - gable roofs. The optimal angle of inclination of the slopes is about 45 ° - this design is able to withstand serious snow and wind loads.

If you want to equip the attic, other types of roofs are used. In particular, this is a gable roof with broken slopes - in the upper part the slopes are gentle, and in the lower part they have a sharp slope. For roofs of this type, it is necessary to build a truss system of a more complex design.

In some cases, an asymmetrical gable roof is performed, the ridge of which is located offset from the center. The scheme of such a roof is developed taking into account the characteristics of the building. A gable roof can also be half-hip. In this case, the design differs from the gable roof by the presence of sloping roof elements above the gables.

Installation of the truss system

Before starting the installation of the gable roof truss system, it is necessary to fasten the Mauerlats to the longitudinal walls using anchor bolts. Next, you should decide on the optimal section of the rafter legs, which depends on their length and the distance between them. To do this, you need to produce. If it is required that the lumber have a different width and length of the rafter legs, then the required size is achieved by splicing (building) them with fasteners.

To use insulation, you should choose a rational distance between the rafters so that you have to cut the heat-insulating material as little as possible.

If you plan to build a roof structure with your own hands, you need to make a calculation based on the width of the roof and its height to the ridge. The standard scheme involves the creation of a rafter structure, which is based on an isosceles triangle. Simple geometric constructions and calculations make it possible to calculate the length of the rafter legs: the allowance for the cornice overhang should be added to the square root of the sum of the squares of the height to the ridge and half the width of the roof.

The number of rafters required depends on the length of the roof and the chosen roofing material. Usually the pitch of the truss structures is 1.2 - 1.5 m. It is not recommended to exceed these values.

Based on the length of the rafter leg and the length of the roof ridge (including allowances for overhangs), the roof surface area is calculated - for this, the indicated values \u200b\u200bmust be multiplied.

When calculating lumber, it is necessary to take into account the presence of such elements of the truss structure as:

Mauerlat;
skate;
rafter legs;
racks;
crossbars;
struts.

Depending on the type of roofing material, the type of crate is determined. It can be sparse (with different pitches) or solid; for soft coatings, continuous sheathing with sheet material is performed. If a half-hipped roof is being installed, it is also necessary to calculate the amount of roofing and structural material for the device of hips - triangular cut tops above the end walls of the house.

All wooden elements require treatment with special compounds that prevent rotting, pest damage, and fire.

Installation of rafters occurs in the following order:

Mauerlat mount

A do-it-yourself rafter frame can be attached to floor beams, but in this case all loads on building construction focus on the attachment points of the floor beams. This option is suitable for small light buildings.

To ensure an even distribution of the load on the upper surface of the walls parallel to the ridge of the future roof, a Mauerlat is mounted, which will serve as the basis of the frame. For the manufacture of Mauerlat, a wooden beam with a section of 150 × 150, 100 × 150 or 100 × 100 is used. It is attached to the wall in one of the following ways:

Calculation of loads and angle of inclination

An accurate calculation of the gable roof truss system is the key to the future strength and reliability of the house. When designing complex roof structure it should only be calculated by a professional. You can independently calculate the roof with small area using simple formulas.

At the very beginning, they are determined with the angle of inclination of the roof slopes. An angle of 5-15° is suitable for a small number of roof coverings. In view of this, the roofing material is first selected, and only then the truss system is calculated. At an angle of inclination above 45°, any roof covering is suitable, but material costs also increase.

It is also necessary to do, depending on the climatic region. Snow load limits are in the range of 80-320 kg/m 2 . On a roof with a slope angle of not more than 25°, the coefficient of transition from snow cover to the roof is 1. For roofs with a slope of 25-60°, the coefficient is assumed to be 0.7.

For example, when the load of the snow cover on the ground is 120 kg/m2, the load on the roof with a slope of 25-60° will be 120×0.7=84 kg/m2.

The wind load is calculated using the coefficient of change in wind pressure and aerodynamic influence.

The weight of the roofing pie is calculated - a constant load, which includes the weight of the batten, counter battens, insulation, roofing material, and also, in the case of an attic, the weight of the interior decoration of the ceilings. The average value of the constant load ranges from 40-50 kg/m 2 .

A properly designed truss system, made by hand, is able to withstand high loads, including:

wind pressure;
snow cover pressure;
person's weight.

The roof should not exert strong or uneven pressure on building structures that transfer the load to the foundation of the house.

Its load resistance depends on the angle of inclination of the roof. The larger the angle, the stronger the frame should be. This parameter also affects the choice of roofing material.

Conclusion

The device of a gable roof implies the creation of a high-quality roofing pie. The gable structure is insulated with sheet or roll materials. It is important to perform high-quality vapor barrier. Used for finishing different kinds roofing materials, from standard slate to high-tech tiles.