In individual construction gable roofs are much more common than other options. The explanation lies not only in practicality for our latitudes, but also in design rafter system.

To arrange a gable roof, the rafters are laid along the simplest scheme, without requiring either serious calculations or complex installation works

In this case, material consumption will be minimal, and strength design - maximum.

Rafter system options

Despite all simplicity structures, rafter systems can be created under a gable roof several types.

Here the choice will depend on how you plan to use attic space and what are the design features of the house itself.

So, roof slopes can be made equal or various lengths. The latter option gives the cottage’s exterior originality and allows it to better adapt to the wind rose and climatic features.

By type of structure rafter systems, gable roofs are divided into the following main ones groups:

Layered rafters

A similar rafter system is used in houses that have in their middle part longitudinal main wall. In this case, it is transmitted from the ridge through the vertical elements to central load-bearing wall. The skate itself takes on the weight rafter legs, delivering the entire system without the need for cross members.

Hanging rafters

This option is the most practical with a house width from 6 to 14 m. Small permissible width home for such a system is explained by significant load on the walls. The rafters rest with all their weight on the walls, the limit strength which is not unlimited.

To reduce the load on the walls, hanging rafters are introduced into the structure additional reinforcement elements: struts, tightening, headstock, crossbars, etc. Strengthening nodes can be located arbitrary Therefore, they are often given a double functional load. For example: Tightenings installed at the lowest point of the rafter system also successfully cope with the role of beams ceiling ceilings

Main design elements

Individual elements and nodes rafter frames can be made of both wood and reinforced concrete. In individual construction, the first option is more common.

The rafter system consists of the following structural elements:

which is a high-strength beam that is laid on load-bearing walls and takes on the weight of the rafters;
rafter legs. These are inclined beams, which are the basis for connecting all elements and determine the shape of the roof;

horse, formed by the junction of roof slopes;
fillies. These are boards or pieces of timber that are used to extend rafter legs to create an overhang if the rafters are not long enough;

eaves, performing the function of protecting walls from snow and water coming off the slopes;
racks, removing part of the load from the rafter legs. Installed vertically under purlins;
struts in the form of inclined beams, the upper part supporting the purlins, and the lower resting against the bench or mauerlat;

puff, connecting the rafter legs horizontally, preventing them from diverging;

lying down - longitudinal beam laid in the same plane with the Mauerlat under the ridge;
sheathing, stuffed across the rafter legs. Thanks to the lathing, the weight of the roofing material is distributed more evenly.

The elements of the rafter system are connected to each other either with nails or bolts through drilled holes. Joints converging at an angle can be reinforced with overhead metal plates or boards.

Important! When preparing material for creating a wooden rafter system, it is necessary to pay attention not only to the quality of drying and absence of damage, but also to the presence of knots. If there are any, their dimensions should not exceed a third of the thickness of the board or timber.

Installation steps

Installation sequence rafter system gable roof will be as follows:

Fastening the Mauerlat

For the device, either logs trimmed at the top and bottom are used, or

Minimum section material – 100 x 150 mm.

Before the final styling Mauerlat will require preparation:

two layers of dense material are applied to the upper part of the load-bearing wall waterproofing material;
the timber is impregnated with solution antiseptic For
individual parts of the Mauerlat are laid out along the walls to determine their lengths. Checked along the way density landing in a prepared place.

fasten Mauerlat can be done in any available way, however more reliable and the easiest way to use anchor fasteners:

anchor bolts strictly vertically fixed on load-bearing walls;
in the bars of the Mauerlat are drilled out holes;
the Mauerlat is mounted on the bolts and finally fixed.

Since the timber has a significant cross-section, its laying over long fastening bolts are often problematic. To simplify the task, before laying the timber on the wall, stacks of thin boards are placed flush with the cut of the bolts. As these boards are removed from under the timber, it will be pushed onto the bolts evenly along its entire length.

Commit the Mauerlat beam can be either screwed on with nuts and washers, or welding piece of reinforcement.

Installation of rafters

Sequence of actions during installation rafters will be like this:

two beams of the first pair are lifted onto the working platform rafter legs, the length of which must be calculated in advance;
in places connections rafter legs with a mauerlat are marked and cut out on them fastening cut;
at the upper junction(under the ridge) both rafter legs are trimmed Thus, to the point overlap they could tightly connect;
the joint of the rafter legs is fixed with nails or bolts. Next, the work is repeated for each pair of rafter legs. Optimal step rafters at the same time - 70 cm;
timber is installed and fixed puffs;
installed under the upper joint of the rafter legs vertical beam (grandmother);
a horizontal one is placed on top of the rafters sheathing.

Ridge installation

To give rigidity rafter system with a central support must be installed ridge run.

It is advisable that there be under it carrier wall. In its absence, planks are laid on parallel load-bearing walls, and beams are installed on them for additional strengthening the support.

For the manufacture of ridge girders, profiled timber with a section of 100 x 150 mm or board with a cross section of 50 x 150 mm or more.

And they are calculated taking into account the wind and snow load on the roof of the house.

Check carefully using a level horizontality ridge run and its parallelism cut the wall.

Attention! Due to incorrect installation of the ridge girder, problems may arise with the installation of roofing materials, leaks will appear, which will lead to emergency roof repairs.

Ridge part rafter system must have maximum possible strength. A certain degree of rigidity of the entire structure is provided runs. However, at the highest point it will be necessary to create an additional stiffening rib.

For this sheathing in the upper part of the roof should be packed tightly. Optimal width reinforced part of the sheathing under the ridge - 40–60 cm. The durable ridge part will not only provide a high level of safety roofing works, but also will make it easier even laying roofing.

From thoughtfulness and thoroughness the execution of the rafter system largely depends efficiency the entire roof. But building a neat, inexpensive and beautiful roof is quite accessible to any home craftsman. You just need to study diagram installation of rafters, purchase material and do not deviate from time-tested recommendations.

For more information on the construction of a gable roof truss system, see video:

A roof with two slopes is the most common option for completing the box of a private house. When manufacturing it, it is important to correctly select the sections of the load-bearing elements, securely fasten the nodes and choose the right type of structure. The rafter system of a gable roof is not very complicated and can easily be made with your own hands.

Classification of rafter systems according to the method of support

The design can be classified according to two criteria. The first of them is the method of supporting load-bearing elements. The gable roof truss system of the house in this case includes the following types:

with layered rafters;
with hanging rafters.

Types of gable roofs with layered and hanging rafters

The construction of a roof using layered rafters involves supporting them at two points. The design in this case avoids the occurrence of serious expansion. To do the installation yourself, you will need the following basic elements:

rafter legs;
Mauerlat;
crossbar;
intermediate posts and struts for large spans load-bearing beams;
sheathing and counter-lattice;
lining thrust bars.

At the top point, installation involves resting on the crossbar. The installation also provides support at the lowest point - the Mauerlat. You can assemble such a structure for your home 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 small house with your own hands. The greatest length of the structure, which allows the installation 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 wooden beams, it will be necessary to provide intermediate posts, which are placed on average every 2 meters. This can only be avoided by using laminated veneer lumber of a sufficiently large cross-section as a crossbar. In this case, free planning 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 to have 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. This 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 to calculate, but allow installation in the under-roof space of a free-plan house. The design assumes the absence of a supporting wooden or metal beam in the upper part. Installation involves supporting the rafters only at the lowest point. At the top, the supporting beams are securely connected to each other. Installing such a system resembles a farm. The structure works under tension, so it is important to prevent excessive horizontal load on the walls of the house. This can be accomplished by performing the following activities:

installation of a monolithic belt along the edge of the walls;
it is necessary to securely fasten the gable roof mauerlat to the wall of the house with your own hands;
To eliminate the thrust, a contraction is established.

Installation of a hanging rafter system

The screed or screed becomes one of the significant elements of the gable roof of a house. It prevents the walls from expanding under the influence of thrust. The following types of fights can be distinguished:

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

It is worth noting that the second option provides less reliability, since the higher the element is mounted, the stronger the impact the rafters have on it. If the contraction turns out to be too long, you need to strengthen it with your own hands. To do this, additional elements of the gable roof of the house - pendants - are installed. They connect the ridge to the middle of the puff, which prevents it from sagging.

The rafter system of a gable roof with hanging rafters allows installation with pre-assembly trusses on the ground, then lift them to the roof and secure them.

This option is suitable only 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 stingray

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

Gable roof with broken and straight slopes

With straight slopes. The easiest way to do it. Allows you to get the job done without major difficulties. The disadvantage of this do-it-yourself roofing option is the reduction in attic space.
With broken slopes. These types of roofing are more difficult to implement. 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 larger than that of the upper one. This way you can raise the attic ceiling and increase the free space. The roof is installed with the installation of an additional crossbar at the fracture site.

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

Basic roof elements

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 selection of their sections.

When installing elements under metal tiles or other coverings, it means using timber with a cross-section of 150x150 or 200x200 mm. It is this size that allows for the most optimal distribution of the load. Next, you will need to choose a fastening method; it depends on the material of the walls. There are several options:

Scheme for attaching the Mauerlat to the wall

Frame, timber or log walls do not require the installation of a Mauerlat. When frame building serves as a support for the rafter legs top harness walls When building fences from timber or logs, the upper crown becomes the Mauerlat. It is important to properly secure these elements in the wall structure.
When using lightweight concrete for construction, additional reinforcement will be required. Lightweight concrete includes materials such as foam concrete, slag concrete, and expanded clay concrete. They can collapse if the roof is not placed centrally on them. To distribute the load evenly, a monolithic reinforced concrete belt is poured along the edge of the walls. During work, special wire, pins or bolts are placed in it, onto which the Mauerlat will be attached.
For brick structures, a reinforced concrete belt may not be required.. In this case, to connect to the strapping beam, a wire is inserted into the masonry, which is then wrapped around the mauerlat and twisted. The second option is one row before the walls are cut into masonry with outside wooden blocks impregnated with antiseptic are introduced. Such plugs and Mauerlat are fastened with staples. It is also possible to use studs and bolts, the fastening of which will require pouring a monolithic belt.

An important point is waterproofing.

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

After securing the Mauerlat, the rafter legs are installed. Their cross-section is selected depending on the pitch of the load-bearing beams, their span, snow load and type of coating. When installing a frame under metal tiles at a pitch 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; to perform a more accurate calculation, it is better to contact a specialist or study additional literature.

There are two ways to attach the rafter legs to the mauerlat:

with a notch;
without her.

Attaching rafter legs to the mauerlat with and without a notch

In the first case, a cut is made on a strapping beam, in the second, a special plank is nailed to the rafters, which becomes a thrust block. Further, for both methods, the work is performed in the same way. Using 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 using wire and staples

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

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

You can perform fastening according to the norms through one leg. This is necessary to more securely attach the roof to the frame of the house.

If the work is done correctly, you won’t have to worry about its condition even in the strongest winds.

Racks, ties, struts

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

Gable roof rafter system: design and components

The gable roof is the most common in construction. For proper installation, it is recommended to study the structure of the rafter system of a gable roof.

Construction of a gable roof rafter system

The rafter system of a gable roof is designed to construct a roof in the form of two rectangles located at a certain angle to each other in the upper part of the structure. This design is quite often used in the construction of private low-rise buildings, various buildings for domestic and economic purposes. In industrial and trading enterprises gable roof installed on buildings for various purposes, having a significant length exceeding the width several times. 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 rear side - a long one, with a smaller angle of inclination. This configuration allows the bulk of atmospheric precipitation to be directed to the non-working area of the enterprise territory.

Figure 1. Diagram of fillies.

Construction of a gable roof is one of the low-cost options and does not require significant physical effort.

It is relatively simple to perform if you have a little experience working with wood materials.

Typical load-bearing elements of the system, specific terms

Figure 2. Sheathing diagram.

In the manufacture of parts of the gable roof rafter system, softwood lumber is used. It is undesirable to use hardwood due to its large specific gravity. Most elements have specific names that are understandable mainly to specialists:

Lezhen - timber with a section of 150x150 mm, 180x180 mm. Placed on the surface of the internal load-bearing wall. Designed to level the surface and distribute loads from the racks.
A rafter leg, or rafter, is a piece made of timber or thick boards. The main element of a 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 pitch 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 is 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 secured with anchor bolts or other reliable method. Distributes the load from the rafter legs to the load-bearing walls.

All parts of a gable roof are connected to each other in different ways. Previously, structures were assembled mainly using staples, nails, and threaded rods. Now manufacturers of building materials offer a large assortment various brackets for assembling roofs of any configuration. Most parts are fastened with self-tapping screws of the required diameter and length, reinforced with special tenons in the brackets.

Additional elements of the rafter system

Figure 3. Diagram of an arch with three hinges.

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

Fillies (Fig. 1) - used to increase the length of the rafter legs. Installed in the lower part for the installation of eaves overhang. The thickness of the fillies is several smaller sizes rafters
A roof overhang, or eaves overhang, is a roof element that protrudes beyond the edge of the wall by about 40-50 cm. Designed to protect walls from precipitation.
The ridge is an element that connects all the rafter legs of the system in the upper part. Installed in a horizontal position.
Lathing (Fig. 2) - boards or bars installed to secure the roof. They are located perpendicular to the rafter legs, additionally performing the function of their fastening. They take the main force from the roofing material and distribute it to the rafters. It is advisable to use for the device edged lumber. If you have limited funds, you can use unedged, clearing it of bark. If the roof is made of soft material, the sheathing is made continuous. This option can be made from boards or plywood, treated protective materials from high humidity. When corrugated sheeting is used, the lathing is performed with a certain step, depending on the weight of the material and its design features.
Struts are elements made of timber or thick boards that strengthen the main structure. Distribute the force from the rafter legs to the supporting parts. Assembled structure from the struts and tightenings, it was called a truss - an enlarged part with the necessary margin of safety.
Racks - are made from pieces of lumber of rectangular or square cross-section. Installed in a vertical position under the ramp. Load from corner connection The roof rafters are distributed through the racks onto the internal load-bearing wall.
Tightening - a block or board that secures rafters in a hanging system. Creates a rigid triangle shape between the rafter legs, compensating for the force of spreading.

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

Two typical methods of constructing rafter systems

Figure 4. Connection diagram of the lower ends of the parts.

The rafter system of a gable roof can be arranged in two main ways:

hanging rafter system;
layered system.

The hanging system is used for buildings with a distance between external walls of less than 10 m, without an internal load-bearing wall in the middle of the building. With another building configuration, 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. The rafter legs located above the columns are mounted with emphasis on the surface of the columns, and hanging rafters are installed between them.

Hanging rafter system

In structures of this type, the installation of rafter beams is carried out on the surface of the external walls. The disadvantage of this method is that it creates a force that pushes the walls apart. To compensate for the load, the beams are tightened using a tie. The structure takes the form of a rigid triangle that retains its shape under load. In some cases, the role of tie bars can be performed by floor beams. This scheme is used when installing attic space attics.

The designs of hanging rafters can be made in various options:

Scheme of reinforced structure.

A simple version of an arch with three hinges (Fig. 3) - the structure is a rigid triangle, two sides of which are the rafter legs. The main load creates the bending force of 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 the tie, using wooden elements or metal brackets.
Reinforced structure (Fig. 5) - a gable rafter system used for roofing large buildings industrial purposes 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 weight of the tightening on the ridge. Since it is almost impossible to find solid lumber of the required length (6 m or more), the tie is made from lengths. The connection of all elements is carried out by direct or oblique insertion. The central piece is called the headstock. The connection of the headstock with the tightening is done by collet twisting with the ability to adjust the tension.
The device of an arch with a tightening in the upper part of the rafter beams (Fig. 6) is used when installing 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 sideways movement of the beams along the beam, but allow sliding across. This ensures uniform load distribution and stability of the entire system. The rafters must form an overhang.

Many system design options have been developed hanging type. Most are used for relatively small buildings without supporting structures inside the buildings. For larger buildings, you need to use a layered rafter system.

Layered rafter 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-to-wall dimension of more than 10 m.

Figure 6. Arrangement of an arch with a tightening at the top of the rafter beams.

A correctly executed system of non-thrust rafter beams allows you to get rid of the forces pushing the walls apart. The surface of the slopes is subjected only to bending forces. There are 3 main options for designing such systems. In all options, the lower ends of the rafter beams are fastened using the sliding support method. For insurance, an additional fastening is installed between the support beam and the rafter leg.
You can use a steel strip or wire tie. The options differ in the method of connecting the upper ends of the rafter beams and connecting them to the ridge beam. One of the options involves laying the rafters on a beam in the form of a sliding support with a cutout device. Fastening can be done using brackets or special brackets. The gable roof, constructed according to the following option, is the most popular due to the simplicity of the device. The top of the rafter beams can be made end-to-end or overlay with grooves cut out. The corner must be fastened using any of the available methods and fixed to the ridge beam. The third option involves a rigid connection of the purlin and rafter beams. For fastening to the rafter legs, pieces of boards are stuffed on both sides. A large bending force is generated 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 rafter system. One option to increase strength is to install a strut. The part takes on the load from the rafter leg, experiencing a compression force. To correctly select the installation position of the element, you need to measure an angle of 45-53° from the horizontal plane of the building. The additional support device turns a conventional beam into a reinforced version consisting of two spans. To install the struts, no calculations are required; you just need to secure it under the rafter beam, cutting out the joining angle with maximum precision.

Technology of device two pitched roofs simple, you can do everything yourself. Work must begin with the installation and fastening of the base to the walls, then mount the gables. It is advisable to carry out work on the manufacture of rafter beams and enlargement of structures on the ground, lift the assembled elements, install them on the building, and fix them using temporary fasteners. After assembling and installing all the elements, you should secure the sheathing and begin installing the roof.

Gable roof rafter system: installation and diagrams

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

Do-it-yourself rafter system for a gable roof: a review of hanging and layered structures

Rafters perform a number of significant roofing functions. They set the configuration of the future roof, absorb atmospheric loads, and hold the material. Among the rafter's responsibilities is the formation of smooth planes for laying the covering and providing space for components roofing pie. In order for such a valuable part of the roof to flawlessly cope with the listed tasks, information is needed about the rules and principles of its design. The information is useful both for those who are constructing 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 device rafter 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, angle. There are combined structures with the most heavily loaded steel parts and wood elements in less critical areas.

In addition to its “iron” strength, metal has many disadvantages. These include thermal qualities that are unsatisfactory to the owners of residential buildings. The need to use welded joints is disappointing. Most often, industrial buildings are equipped with steel rafters, and less often, private cabins assembled from metal modules.

In the matter of independent construction of rafter structures for private houses, wood is a priority. It is not difficult to work with, it is lighter, “warmer”, and more attractive in terms of environmental criteria. In addition, to perform nodal connections you will not need welding machine and welding skills.

Rafters - a fundamental element

The main “player” of the frame for constructing a roof is the rafter, which among roofers is called a rafter leg. Beams, braces, headstocks, purlins, ties, even a Mauerlat may or may not be used depending on the architectural complexity and dimensions of the roof.

Rafters used in the construction of gable roof frames are divided into:

Layered rafter legs, both heels of which have reliable structural supports under them. The lower edge of the layered rafter rests against the mauerlat or the ceiling crown of the log house. The support for the upper edge can be a mirror analogue of the adjacent rafter or a purlin, which is a beam laid horizontally under the ridge. In the first case, the rafter 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 - a tie. The latter connects the two lower heels of adjacent rafter legs, resulting in a triangular module called a rafter truss. Tightening dampens the tensile processes, so that only vertically directed load acts on the walls. Although a structure with hanging rafters is braced, the bracing itself does not transmit to the walls.

In accordance with the technological specifics of rafter legs, the structures constructed from them are divided into layered and hanging. For stability, the structures are equipped with struts and additional racks. To support the top of the layered rafters, planks and purlins are installed. In reality, the rafter structure is much more complex than the elementary templates described.

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

Subtleties of fastening rafter legs

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

The top of brick walls is sometimes specially laid out so that along the outer perimeter there is something like a low parapet. This is so that the mauerlat placed inside the parapet and the walls do not push apart the rafter legs.

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

How to do without mind-boggling calculations?

It is highly desirable that the section and linear dimensions wooden beams were determined by the project. The designer will provide clear calculation justification for the geometric parameters of the board or beam, taking into account the entire range of loads and weather conditions. If the home craftsman does not have a design development at his disposal, his path lies on the construction site of a house with a similar roofing structure.

You don’t have to pay attention to the number of floors of the building being constructed. It is easier and more correct to find out the required dimensions from the foreman than to find out them from the owners of a shaky self-built building. After all, in the hands of the foreman is documentation with a clear calculation of the loads per 1 m² of roof in a specific region.

The installation pitch 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 styling 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 corrugated sheets, 1.5-2.0 m is acceptable. However, even if the pitch required for proper 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 understand the pitch of the rafters before constructing the rafter system.

Craftsmen calculate the pitch of the rafters according to the design features of the building, simply dividing the length of the slope into equal distances. For insulated roofs, the pitch between the rafters is selected based on the width of the insulation slabs.

Rafter structures of layered type

Layered rafter structures are much simpler to construct than their hanging counterparts. A reasonable advantage of the layered scheme is to ensure adequate ventilation, which is directly related to long-term service.

Distinctive design features:

It is mandatory to have support under the ridge heel of the rafter leg. The role of support can be played by a purlin - a wooden beam resting on posts or on the internal wall of the building, or the upper end of an adjacent rafter.
Using a Mauerlat to erect a truss structure on walls made of brick or artificial stone.
The use of additional purlins and racks where the rafter legs, due to the large size of the roof, require additional support points.

The disadvantage of the scheme is the presence of structural elements that affect the layout of the internal space of the attic being used. If the attic is cold and it is not intended to organize useful rooms, then the layered structure of the rafter system for installing a gable roof should be given preference.

Typical sequence of work for the construction of a layered truss structure:

First of all, we measure the heights of the building, the diagonals and horizontality of the upper cut of the frame. If we identify vertical deviations in brick and concrete walls, we eliminate them with a cement-sand screed. Exceeding the heights of the log house is cut off. By placing wood chips under the mauerlat, vertical flaws can be combated if their size is insignificant.
The floor surface for laying the bed must also be leveled. It, the Mauerlat and the girder must be clearly horizontal, but the location of the listed elements in the same plane is not necessary.
We treat all wooden parts of the structure with fire retardants and antiseptics before installation.
We lay waterproofing on concrete and brick walls for installation of the Mauerlat.
We lay the mauerlat beam on the walls and measure its diagonals. If necessary, we slightly move the bars and turn the corners, trying to achieve the ideal geometry. Align the frame horizontally if necessary.
We mount the Mauerlat frame. The beams are joined into a single frame using oblique notches; the joints are duplicated with bolts.
We fix the position of the Mauerlat. Fastening is done either with staples to wooden plugs installed in advance in the wall, or with anchor bolts.
Mark the position of the prone position. Its axis should recede from the mauerlat bars at equal distances on each side. If the run will rest only on posts without supports, we carry out the marking procedure only for these posts.
We install the bed on a two-layer waterproofing. We attach it to the base with anchor bolts, and connect it to the inner wall with wire twists or staples.
We mark the installation points of the rafter legs.
We cut out the racks to uniform sizes, because... Our bed is exposed to the horizon. The height of the racks should take into account the cross-sectional dimensions of the purlin and beam.
We install racks. If provided by the design, we secure them with spacers.
We lay the purlin on the racks. We check the geometry again, then install brackets, metal plates, and wooden mounting plates.
We install a test rafter board and mark the cutting areas on it. If the Mauerlat is set strictly to the horizon, there is no need to adjust the rafters on the roof after the fact. The first board can be used as a template for making the rest.
We mark the installation points of the rafters. For marking, folk craftsmen usually prepare a pair of slats, the length of which is equal to the clearance between the rafters.
According to the markings, we install the rafter legs and fasten them first at the bottom to the mauerlat, then at the top to the purlin 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 made flawlessly, the layer boards are installed in any order. If there is no confidence in the ideal structure, then the outer pairs of rafters are installed first. A control string or fishing line is stretched between them, according to which the position of the newly installed rafters is adjusted.

The installation of the rafter structure is completed by installing fillets, if the length of the rafter legs does not allow forming an overhang of the required length. By the way, for wooden buildings the overhang should extend beyond the contour of the building by 50 cm. If you plan to organize a canopy, separate mini-rafters are installed under it.

Hanging rafter systems

The hanging variety of rafter systems is a triangle. The two upper sides of the triangle are folded by a pair of rafters, and the base is the tie connecting the lower heels. The use of tightening allows you to neutralize the effect of the thrust, therefore, only the weight of the sheathing, roof, plus, depending on the season, the weight of precipitation, acts on walls with hanging rafter structures.

Specifics of hanging rafter systems

Characteristic features of hanging type rafter structures:

The obligatory presence of a tie, most often made of wood, less often of metal.
Possibility to refuse to use the Mauerlat. A timber frame can be successfully replaced by a board laid on double-layer waterproofing.
Installation of ready-made closed triangles – trusses – on the walls.

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 them is restrictions 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 detailed calculations for the proper installation of cornice units.

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

Subtleties of long-span hanging systems

The tie is the longest element of a hanging rafter structure. Over time, as is typical for all lumber, it becomes deformed and sags under the influence of its own weight. Owners of houses with spans of 3-5 meters 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, there is a very significant component in the installation diagram of the rafter system for a long-span gable roof. This is a pendant called a grandmother. Most often it is a block attached with wooden pegs to the top of the truss. The headstock should not be confused 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 hangs, as it were, on the ridge assembly, and a tightening is attached to it using bolts or nailed wooden plates. To correct sagging tightening, threaded or collet-type clamps are used.

The tightening position can be adjusted in the area of the ridge assembly, and the headstock can be rigidly connected to it by a notch. Instead of a bar in non-residential attics, reinforcement can be used to make the described tension element. It is also recommended to install a headstock or hanger where the tie is assembled from two beams 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 proper placement of vector loads acting on the system. As a result, the rafter system is stable with minor and not too expensive modernization.

Hanging type for attics

In order to increase usable space the tightening of the rafter triangles for the attic is moved closer to the ridge. A completely reasonable move has additional advantages: it allows you to use the puffs as a basis for lining the ceiling. It is connected to the rafters by cutting with a half-pan and duplicating with a bolt. It is protected from sagging by installing a short headstock.

A noticeable disadvantage of the attic hanging structure lies in the need for accurate calculations. It is too difficult to calculate it yourself; 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 rafter systems cannot be the same, because:

In the construction of a layered structure, a board or beam of small cross-section is used to make rafter legs. Because layered rafters have two reliable supports underneath 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. To make a tightening, a material with a similar cross-section is required. Even taking into account the abandonment of the Mauerlat, the consumption will be significantly higher.

It will not be possible to save on the grade of material. For the load-bearing elements of both systems: rafters, purlins, beams, mauerlat, headstocks, racks, 2nd grade lumber is needed. For crossbars and tensile ties, grade 1 will be required. In the manufacture of less critical wooden overlays, grade 3 can be used. Without counting, we can say that in the construction of hanging systems, expensive material is used in greater quantities.

Hanging trusses are assembled in an open area next to the facility, then transported, assembled, upstairs. To lift weighty triangular arches from timber, you will need equipment, the rental of which will have to be paid. And the project for complex nodes of the hanging version is also worth something.

There are actually many more methods for constructing rafter 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 tricks. However, the information presented is enough to cope with the construction of a simple truss structure.

Do-it-yourself rafter system for a gable roof: device, design, installation

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

Construction of houses

When constructing one-story houses, a 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 design of the gable rafter roof is not too complicated. And you will successfully master this work on your own.

Design of a 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, drains from the roof naturally. The gable roof has a rather complex structure. It consists of the following structural units: mauerlat, rafter system, fillies, ridge, roof overhang, bed, struts, tie-downs, sheathing and racks:

Mauerlat. This element performs the functions of transferring and distributing the load created by the rafter system onto the load-bearing walls of the house. To make the Mauerlat, timber is used, which has a square cross-section - from 100 by 100 to 150 by 150 mm. It is better to use coniferous wood. The timber is placed around the perimeter of the building and secured to the external walls. For fastening, special rods or anchors are used.
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 cross-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 heavy coverings, place rafter legs more often.
Horse. This element connects the two slopes at the top of the roof. The ridge is formed after connecting all the rafter legs.
Fillies. 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 the formation of an overhang. To make this structural unit, take a board that has a smaller cross-section than the rafter. The use of fillies facilitates the construction of the rafter 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 collapsing. The overhang from the wall, as a rule, protrudes 400 mm.
Sill. It is located on the inner wall and serves to evenly distribute the load from the roof pillars. To make the bed, a timber is used, which has a cross-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 internal 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. The struts and tightenings form robust construction which is called a farm. Similar device designed to withstand loads over large spans.
Puff. This structural unit, together with the rafters, forms a triangle. It does not allow the rafters to move in different directions.
Lathing. This structure consists of boards and bars. They are attached perpendicular to the rafters. Lathing is necessary to evenly distribute the weight of the roof covering and the loads created by weather conditions onto the rafters. In addition, sheathing is required to fasten the rafters together. When arranging a soft roof, moisture-resistant plywood should be used to create sheathing rather than boards and bars.

Types of gable roof rafter system

There are gable rafter systems with hanging and layered rafters. Ideally, the design contains a combination of them. It is customary to install hanging rafters if external walls located at a distance of less than 10 m. Also, between them there should no longer be walls 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 make a tie 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 capable of deforming under loads that appear in any direction. The tightening will be stronger and more powerful if it is positioned higher. The tie beams are the floor beams. Thanks to their use, the hanging rafter system of a gable roof serves as the basis for arranging the attic floor.

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

DIY gable rafter 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 much pressure on the walls of the house. A properly constructed gable rafter roof evenly distributes the load across all load-bearing walls.

Calculation of a gable roof

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

When erecting a gable roof, remember that it must slope at an angle of more than 5 degrees. It happens that the roof slope reaches 90°.
For areas with heavy rainfall, and when the roofing does not fit tightly, steep slopes are made. 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 solution will be a broken roof structure. It will have a flat top part, and a sharp slope at the bottom.
In regions with strong gusts of wind, flat roofs are installed. 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. Make sure the gable roof is not too steep. But the slope should also not be very gentle.
When choosing a large roof angle, its windage increases, and, accordingly, the price of the gable roof rafter system and sheathing increases. After all, such a slope entails an increase in the roof area and, accordingly, the amount required material– construction and roofing.

When purchasing materials for constructing 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, the slope is an inclined rectangle that is placed along a long load-bearing wall. To determine the area of the 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 roof overhang above the gable is added to the length. Remember that there are tabs on both sides.
The width of the slope is the length of the rafter leg. The length of the roof overhang above the load-bearing wall is added to it.

In order to correctly design the structure, it is recommended to carry out an accurate calculation of the rafter system of a gable roof, 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 the weight of each layer of the “pie” - thermal insulation, vapor barrier and waterproofing materials, rafter system, sheathing and roofing material itself. Calculate the weight per 1 m2.
Increase results by 10%. You can also take into account the correction factor. In our case K=1.1.
If you plan to change the roof structure over time and increase its angle of inclination, then factor in a safety margin into the calculation. Immediately take higher loads than those you received at the time of calculation. It is recommended to start from a value of 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. When making this calculation, take into account the slope of the slope. If the gable roof forms an angle of 25 degrees, then assume a snow load of 1.
If the roof is equipped with a greater slope - up to 60 degrees, the correction factor reaches 1.25. Snow loads for angles greater than 60 degrees are not taken into account.
The rafters transfer the entire load from the created structure to the load-bearing walls. Therefore, their parameters must be taken accordingly. Select the cross-section and length of the rafter leg, depending on effective load on the roof and the corner of the slope. Increase the obtained values by 50% to ensure a high safety margin.

Mauerlat installation methods

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

If logs or beams were used to build the walls, then the top beam will act as a Mauerlat, as shown in the photo of the gable roof rafter system.
If you used brick to build the walls, then wall up metal rods into the masonry. They must have a thread cut for attaching the Mauerlat. Install rods every 1-1.5 m. Choose rods with a diameter of at least 10 mm. Lay waterproofing between the masonry and the 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 have threads to the reinforcement.
For the Mauerlat, use a beam that has a cross-section of 15 by 15 cm. It will act as a kind of foundation for the rafter system.
Place 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, otherwise the wind may blow it off.
It is recommended to place the Mauerlat on top of the waterproofing layer. To connect all parts into one, use bolts and metal plates.
To avoid sagging, make a lattice from racks, struts and crossbars. To do this, take boards measuring 25x150 mm. The angle between the strut and the rafter leg should be as straight as possible.
If you use a rafter leg that is too long, install another support. She should rest on the bed. Each element is associated with two neighboring ones. The result is a stable structure around the entire perimeter of the roof.

Fastening rafter legs

Most the best option gable roof rafter system - a combination of inclined 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 best materials as materials. quality wood. Beams that have cracks and knots should absolutely not be used.
The rafters have standard sizes– 50x150x6000 mm. When 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 the board along them. The template is ready.
Cut the rafters according to this template. After this, make the top cut on them.
Take the resulting workpiece and bring it to the floor beam to mark the bottom cut in place.
Install all rafters. At the same time, remember that after installing one leg, you must immediately install the opposite one. This way you will quickly remove the lateral loads on the ridge beam.
If the slope is too long, then standard boards not enough to make a rafter leg. In this case, you can join two boards together. To do this, sew on them a piece of wood of a similar cross-section. It should have a length of 1.5 - 2 meters. According to the gable roof rafter system diagram, the joint should always be at the bottom. Install an additional stand under it.
Attach the rafter leg to the ridge beam using nails. To attach the rafters to the floor beam, use self-tapping screws. Metal mounting plates are also suitable. In addition, a few nails are added.
If you are building a structure entirely from hanging rafters, then skip the next stage. When erecting a structure with layered rafters, you need to think about the supports that are installed on the floor. To reduce the deflection of the rafters, correctly calculate the location of such supports.
If you are building a gable mansard roof, the intermediate posts will become the frame for the side walls.
When performing this work, maintain a certain pitch of the beams. Set its size at the design stage.
After installing the rafters, attach the ridge. It is placed along their upper edge. For fastening use metal corners or staples. And the most popular are bolts.

Rigidizing the structure

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

For small buildings, such as saunas, cottages, utility buildings, and roofs with the simplest hanging rafter system, connect each pair of rafters from below using a tie, and from above using a crossbar.
For large buildings that are also lightweight, choose a light roof. The walls must support it.
If the house is 6-8 m wide, then the structure should be strengthened. Place the support in the middle. Such racks are called headstocks. 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 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 lower end of the headstock and to each other, as shown in the video about the gable roof rafter system.
In situations with long roofs, the gable beams should be relieved. This is done by installing braces. The top end should rest against the corner of the gable. The lower one is mounted on the central floor beam. For fastening, use a beam that has a large cross-section. This way you can prevent them from breaking if there are strong gusts of wind.
In areas where winds prevail, the rafters must be resistant to such influences. Strengthen them by installing diagonal braces. The boards are nailed from the bottom of one rafter to the middle of the next.
For greater rigidity, when creating the most critical fastenings, it is better not to use nails. Use pads for this and metal methods fasteners Nails will not be able to provide high-quality fastening, since the wood can dry out after some time.

Lathing of the rafter system

The final stage of installing a gable roof rafter system is the creation of sheathing. It is on this that you will lay the roofing covering. Carry out the work in the following sequence:

Select dry timber for sheathing. There should be no cracks or knots on it. Nail the beams from below. Attach two boards near the ridge so that there are no gaps. The sheathing must withstand the weight of the upper roofing material and not bend under the weight of the workers.
If you arrange soft roof, make two layers of sheathing. One is sparse, the second is continuous. The same goes for roll roofing. To begin, place boards parallel to the ridge beam 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 this, check that there are no errors left on the sheathing - irregularities and knots. Also check that there are no nail heads sticking out.
Place one layer of timber under the metal tiles. It should have a cross section of 50 by 60 mm. Proceed in the same way when using slate or steel roofing sheets. Maintain a step between the beams, depending on the roofing you choose - from 10 to 50 cm. Hammer the nails closer to the edges of the board, and not in the middle. Drive the hats in deep. This way they won’t be able to damage the roof later. If you are making sheathing for metal tiles, then remember that the connection of the timber at the same level should fall on the rafter.

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

Construction of a gable roof truss system, Construction Portal

Construction of houses When constructing one-story houses, a roof with two slopes is very popular. This is due to the speed of construction of the structure. According to this parameter with

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Step-by-step installation of a gable roof - a guide for the home craftsman

Professionals consider the gable system to be the simplest and most affordable, this is partly true, but for the home craftsman self-installation Roofs of any configuration can become a problem. Therefore, next we will analyze step by step all the stages of constructing a gable structure, starting with professional terminology and ending with the arrangement of the roofing pie.

Basic concepts and subtleties

Before you go to the store for materials and try to do something with your own hands, it would be useful to understand what exactly you want, because gable systems come in several types. And to create a basic project, you need to know the basic principles and terminology.

What and what is it called

Mauerlat- this is a beam that serves as a support for the rafter legs and is mounted along the perimeter of the external load-bearing wall. The minimum cross-section of such a beam is 100x100 mm. It can be monolithic or stacked, that is, consist of 2 beams of smaller cross-section;
Rafter leg- this is an inclined beam with its lower side resting on the mauerlat, and the upper connection of such beams forms a ridge; in a gable system there are 2 of them. The minimum thickness of the rafter leg is 50 mm. The width of the beams can be from 150 mm or more;
Farm- the connection of two rafter legs (triangle), called a truss. The number of trusses depends on the length of the building, the minimum truss pitch is 600 mm, the maximum is 1200 mm. The choice of pitch depends on the weight of the roofing pie, as well as on the snow and wind load in the area;
Horse- the upper line of connection of the rafter legs and two roof planes, it is also called the ridge girder;
fillies- overhangs from the edge of the rafter leg to the outer load-bearing wall. A frontal board is placed on the front side of the overhang, which often serves as a support for installing roof drain gutters;

Racks- vertical supports that take on a significant part of the weight of the rafter structure. In small houses, the post is placed only in the center, and supports the ridge. For large roof sizes, as well as in houses with residential attic intermediate racks are installed;
Struts- small beams that are mounted at an angle and provide additional stability to the trusses;
Puff- a horizontal beam connecting 2 adjacent rafter legs. It can also be called a fight or a crossbar;
Sill- this is to some extent an analogue of the Mauerlat, only here the beam is mounted on top of an internal load-bearing wall or several internal walls;

Lathing- boards stuffed on top, perpendicular to the rafters. The sheathing can be continuous or with gaps, it all depends on the weight and structure of the roofing pie;
Run- an analogue of ridge beams, but ordinary purlins are mounted along the entire roof plane, they strengthen the trusses and serve as additional support for the rafter legs.

Types of gable structures

Illustrations	Explanations
	Symmetrical system. The symmetrical rafter system is considered the most reliable and easiest to install. The loads here are distributed evenly, so the thickness of the roofing pie does not play a big role.
	Asymmetrical system. Asymmetry is good not only for its original look, it is easier to arrange a living space under such a roof. But, at the same time, much more calculations will be required, because the loads on the base and the roofing pie vary greatly.
	Broken roof. Formally, such a roof already has more than 2 slopes, but the installation procedure for broken and classical structures is similar. Therefore, they are combined into one direction.

What is the difference between layered and hanging systems?

If the distance between the external walls does not exceed 10 m, and there is no permanent wall inside the house, then hanging rafters are installed. They rest on the Mauerlat and are pulled together at the bottom by ceiling beams, plus in some cases additional transverse ties are installed.

Installation of layered rafters can only be carried out if there are permanent walls inside the house. In this case, the size of the building does not matter much. The layered system is much more practical and durable, because a significant part total load takes over the pier.

A few words about calculations

When calculating any roof, 3 main components are taken into account - constant, variable and special loads.

Constant loads include, first of all, the weight of the roofing and the rafter system itself. In unheated attics, this weight often does not exceed 30 kg per 1 m², and if you are installing a full-fledged roofing pie with insulation, then the weight here can reach up to 50 kg;

Variables include snow and wind loads. To calculate, you need a wind rose and average precipitation for the region. Here SNiP 2.01.07-85 will help you, according to it in Russia snow load ranges from 80 to 320 kg/m². Both snow and wind loads are multiplied by a factor depending on the angle of the roof, and this factor is constant;

If your gable roof has a slope angle equal to or greater than 60º, then the snow load can be ignored; snow is not retained on such a roof. But the wind pressure here is much higher.

Special stresses include natural disasters such as earthquakes and hurricanes. Fortunately, there are few such places in our country, so they are rarely taken into account in calculations. The video below in this article provides detailed instructions for calculating the roof.

Stages of installation of a gable roof

The entire installation can be divided into mounting the Mauerlat, then installation in progress rafters, racks and struts, and it all ends with the arrangement of the roofing pie.

How to install the Mauerlat

Fastening the Mauerlat, first of all, depends on what material your house is built from. So, if the house is brick or made of cinder block, then a couple of layers of roofing material are rolled out over the wall and the Mauerlat beam is screwed on top with anchor bolts or any other studs.

With houses from cellular concrete(foam or aerated concrete) everything is a little more complicated. Neither an anchor bolt nor a pin will hold in such a block, so a reinforced reinforced concrete belt is poured around the entire perimeter of the wall, into which iron pins are initially embedded to secure the Mauerlat.

In wooden houses, the rafter system is mounted without a mauerlat at all; more precisely, the role of the mauerlat is played by the upper beam.

Rafter legs in wooden houses are connected to top beam(with a Mauerlat) according to the sliding principle, that is, not rigidly. This installation allows the rafters to move as the house shrinks.

We install a simple rafter system

Illustrations	Recommendations
	Mauerlat. IN in this case The installation of the Mauerlat was carried out on a built-in threaded pin; the pin was locked on top through a washer. Plus, an anchor bolt was driven nearby for strength.
	Extreme farms. To keep the outer trusses in the desired position, they were screwed in the center and additionally secured with spacers and posts. These racks are needed only during the installation of the rafter system; then they are dismantled.
	Connection of rafters with Mauerlat. Stage 1. The first to be installed on the Mauerlat are vertical racks. They are cut from the same timber as the rafter legs. The outer racks are fixed with two corners, 8 screws in each, and the middle ones are fastened in the same way, with only 1 corner.
	Stage 2. WITH reverse side Exactly the same stand with a corner is installed on the rafter leg. The rafter leg itself is connected to the posts with long self-tapping screws and through pins with a diameter of 12 mm.
	Stage 3. On the outer trusses, in addition to the mounting on the Mauerlat, intermediate racks are also installed (they are not subsequently removed).
	Stage 4. A triangle is rigidly attached between the two posts holding the rafter legs on the mauerlat.
	Ridge run. Stage 1. The ridge beam must pass exactly under the connection of all trusses. To secure this beam, 2 tie-rods were installed on the outer trusses, and the beam itself was screwed to the tie-rods with corners. Bars of this cross-section are usually 6 m long, so they can be extended if necessary. To make the connection strong, we attached the same bars on both sides and tightened everything with 4 12 mm studs.
	Stage 2. For reliability, the connections of the rafter legs were tightened with metal plates with 6 12 mm studs, 3 studs in each beam. If there are not enough such overlays with studs for each truss, then pull at least the outer ones, and fix the rest on both sides with plates on self-tapping screws.
	Tightenings on the end trusses. On the outer trusses, the tie rods are installed inside, between the rafter legs, and secured on both sides with metal plates.
	Tightenings on intermediate trusses. 2 tie-rods are placed on the intermediate trusses, they are applied on both sides and tightened with two studs (12 mm) and four self-tapping screws.
	Reference point. In order to align the intermediate trusses in the same plane, immediately after installing the outer trusses, a cord is stretched between them and the remaining trusses are mounted along it.
	Cutout in the rafters. In order for the rafter legs to rest more firmly on the Mauerlat, triangular cutouts are made in them. But such cutouts are made only in block houses; in wooden houses there are no cutouts, where the rafters must slide.
	fillies. There should be at least 30 - 40 cm from the edge of the rafter to the wall. In this case, 50 cm was made. A tolerance of 10 cm was left for insulation and wall cladding with siding.
	Rafter system - the result. We have created a lightweight hanging type rafter system. B-pillars We didn’t install it, so the attic can be made habitable. The puffs on the middle trusses are paired, and on the outer trusses they are single. At the top point of the trusses there is a single ridge beam. Since the system is hanging, the rafter legs have double reinforced fastening.

There is one more important point: in wooden houses, in addition to the sliding fastening of the rafter legs to the mauerlat, it is advisable to also make the ridge connection movable. The easiest way is to screw metal plates on both sides of the rafter legs and “sew” these plates together with a central pin, as in the photo below.

How does a roofing pie work?

Roofing pie diagram for everyone pitched roofs similar, but the installation technology and sequence of actions may differ slightly. If there are enough funds for quick installation, then the pie is installed from the bottom up and the entire roof is completed in a maximum of a week. But if the house is being built gradually, then they act differently.

If you have limited financial resources, you can first install a roof under cold attic, and then (when money and time appear) insulate everything with your own hands.

To begin with, a vapor barrier is installed on top of the rafter system. The rolls are rolled out perpendicular to the rafters and cover each other from bottom to top. As the roll is rolled out, the membrane is nailed to the rafters with counter batten bars (50x50 mm), and the main batten is placed on top of these bars.

After the first roll is rolled out and secured, the next one is rolled out on top of it with an overlap of 150 mm. After which it is also fixed with a counter-lattish, onto which the lathing is stuffed. There is no need to measure the overlap of the next roll; there is a line on it for this purpose.

The pitch of the under-roof sheathing can be different, for example, the slats are packed under the metal tiles with a gap of about half a meter, and if you ceramic tiles, then you need to focus on the dimensions of the plates.

Insulating the roof from the inside is also easy. Mineral wool slabs are simply inserted from below between the rafters. Then the insulation is hemmed with another membrane, onto which the final finishing of the attic can be sewn.

If you prefer soft bitumen shingles, then the diagram below shows step-by-step instruction its arrangement.

Conclusion

A gable roof is a good choice for a novice home DIYer. I tried to highlight the main stages and subtleties of its arrangement. If you still have questions, write in the comments, I will try to help.

October 9, 2017

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Properly designed and assembled according to technology, the roof serves as a barrier preventing cold air and moisture from entering the house. From the outside, with the naked eye we see only a small part of the structure - the roofing. But the roof frame, which is the most important component, performs the main supporting functions and takes on the effects of wind and snow loads.

To prevent it from deforming as a result of operation, it is necessary to correctly calculate the cross-sectional size of its elements and determine the distance between them, taking into account the weight of the roofing material, slope and climatic conditions. In this article we will tell you what the rafter system of a gable roof of a house is, what it consists of, how it is designed and assembled with your own hands.

A rafter system for a gable roof of a house is a system of interconnected supporting elements that together make up the frame of the structure.

It is made of wood or metal in accordance with the calculation of the loads that will affect them during operation. The roof rafter frame performs the following functions:

Gives the roof slopes the necessary slope. The traditional shape in the form of an equilateral rectangle of a gable roof is given by the rafter frame, which forms the slope between the base of the roof and its ridge. The angled surface allows snow and water to slide freely off the slope.
Distributes the load from the weight of the roofing pie. The weight of the roofing pie, taking into account the snow load, can reach up to 500 kg/m2, so the gable roof is subject to intense load, especially in winter. The rafters of a gable roof evenly distribute the weight that rests on them, and then transfer the load to the load-bearing walls and foundation of the house.
Serves as a basis for attaching thermal insulation and roofing material. The rafter frame of the roof serves as a kind of skeleton of the structure around which its “body” is built. Thermal insulation should be installed between the rafter legs, and a roofing covering should be fixed to the sheathing, which protects against moisture penetration.

Please note that the design of a gable roof truss system is quite complex to design and assemble, especially if the craftsman lacks experience. After all, in order for it to be able to withstand intense loads, you need to correctly calculate the cross-section of the rafters and the pitch of the rafters, taking into account the slope and length of the slopes, the roofing material used, and also draw up a drawing according to which the assembly will be carried out.

Types of rafter systems

Rafter systems differ in many factors; their composition depends on the layout of the wooden or brick house, the total weight of the roofing pie, the material from which the frame is made, as well as the type of roofing covering.

An important design characteristic is their load bearing capacity, which determines how much weight they can support without deformation. According to their characteristic features, the following types of rafter systems are distinguished:

Layered

A layered rafter frame is a frame whose rafters have 2 support points. The upper end of the leg rests on a ridge girder mounted on vertical posts fixed to the inner wall. And with the lower end it is installed on the Mauerlat.

Assembly of a layered rafter system on a gable roof is possible only if there is at least 1 load-bearing partition or main column located inside the house. This design is often called non-thrust, because the second support point of the rafters compensates for the thrusting load on the walls of the house, which is assumed by the hanging installation of the frame.

Rafter legs of the layered type experience load only in bending, which can be eliminated by various struts. The layered rafter system allows you to cover houses up to 14 meters wide.

Hanging

The hanging rafter system is distinguished by the fact that its rafters rest only with their lower end on a mauerlat beam installed on the external load-bearing walls. The upper end of the rafter legs of this design does not rest on anything, but seems to hang in the air, which is why 2 types of load arise: bending and expansion.

The thrust load of such a layout of elements on the external walls is so great that it has to be compensated with the help of numerous crossbars and ties, due to which the rafter pairs are tied together.

The structure of a gable roof with hanging rafters consists of triangular trusses, the rigid form of which is not subject to loads. The complexity of the dangling circuit is believed to be much higher.

The rafter system of a gable roof can be easily installed with your own hands if you correctly calculate the pitch of the rafters, that is, the distance between the rafters and the size of their cross-section.

Combined

Combining the best of both systems, it is recognized as the most reliable. It is used in cases where columns, rather than walls, are used indoors as support inside the house. Then hanging and layered rafters can be alternated to strengthen the structure with additional elements without increasing the consumption of building materials.

Important! A sliding rafter roof is another type of frame, which differs in that the rafter legs are installed on the Mauerlat not using a rigid fastening, but using a movable support. Sliding mount allows the roof to change dimensions within the power reserve during the shrinkage of a wooden house.

Design

The construction of a gable roof truss system of any of the listed types is a set of auxiliary and supporting elements. They distribute the weight of the roofing pie evenly, and also compensate for the bursting and bending loads that arise between them.

The cross-section, length and pitch of the rafters are determined using an engineering calculation that takes into account the weight of the roofing pie, climatic conditions in the construction region, as well as the slope of the structure. The rafter frame of a gable roof usually includes the following elements:

Mauerlat. Install the Mauerlat beam on the outer walls of the house, on which the roof slopes rest. It serves to soften the pressure on the supports and evenly distribute the load from the weight of the roofing pie. It is made of durable timber with a cross-section of 150x150 mm or 200x200 mm and is attached to the upper chord of the walls using anchor bolts or long metal studs.
Sill. This is an analogue of the Mauerlat, only it is installed on internal load-bearing walls, and vertical supports must be placed on it for mounting the ridge girder.
Rafter legs. This term refers to frame elements that are made from boards with a cross-section of 150-40 mm and are installed at an angle to the base of the roof, forming an angle of inclination of the slope. The distance between the rafters, their length and thickness are determined using calculations that take into account the total loads to which they are subjected during operation.
Puff. A tie is called a beam that is placed horizontally and connects the legs of one rafter pair to reduce the thrust load on the external walls of the structure. The crossbar is a tie installed under the very ridge of the structure.
Racks. A stand is a vertical beam placed flat to support the ridge girder. It is easy to determine what distance should be between the racks, because it follows the pitch of the rafters.
Struts. Diagonally located supports that support the rafter legs in the middle or at the bottom, preventing them from bending, are called struts.

Please note that determining how to correctly position the elements of the rafter system can only be done by calculating the temporary and permanent loads to which they will be subjected during operation. Calculating the total weight of the roofing pie helps determine the correct distance between the rafters, calculate their length and required thickness.

The calculation of the rafter system of a gable roof is based on the fact that in the frontal dimension it has the shape of an equilateral triangle, the sides of which can be easily calculated using simple trigonometric formulas.

These simple calculations help determine the optimal distance between the rafters, their thickness and length. The design calculations are performed in the following sequence:

Determine the structure and slope of the roof. There are various ways to select the type and slope of the roofing structure. This parameter depends on the climatic conditions and performance characteristics of the selected roofing material.
Determine the total load on the structure. To do this, sum up permanent loads (the weight of the roofing, the weight of the frame, thermal insulation and floors) with temporary loads (snow load, wind load), multiply by a correction factor that takes into account the slope of the slopes, and then add 10-15% to this figure so that the frame had some margin of safety.
Calculate the length of the rafter legs. To do this, they use the Pythagorean theorem, because the truss is an equilateral triangle. It turns out that the square of the length of the rafter leg is equal to the sum of the squares of the height of the blood and half the length of the laying. Knowing how to calculate the length of the rafters, you can calculate the height of the ridge.
Determine the cross section of elements. Optimal cross section elements are selected from tables in accordance with the length of the rafter legs and the distance between them. The higher these indicators are, the thicker the rafters should be.

Remember that before you calculate the rafters for the roof, you need to decide on the basic design parameters. In particular, it is necessary to know exactly the height of the ridge and the slope of the roof, as well as the dimensions of the room being covered. The result of the calculation of roof elements should be detailed diagram rafter system, reflecting their sizes and angles between them.

Calculating the angle of inclination

The angle of inclination of the slopes is selected not depending on aesthetic preferences, but based on weather conditions, taking into account the roofing material. Steeper slopes of 40-45 degrees are constructed in areas with a lot of snow cover, and flatter slopes of 10-20 degrees in places with strong gusty winds.

Keep in mind that the steeper the slope, the higher the consumption of materials, the higher the final cost of the roof. Be sure to take into account the requirements of the material:

Tiles and slate require a slope of at least 22 degrees, otherwise precipitation will seep through the joints between the elements.
Metal tiles are laid at an angle of at least 14 degrees, since they suffer greatly from gusts of wind, they can become deformed or even fly off.
The soft roof allows an inclination angle of up to 5-10 degrees, making it possible to cover slopes of any geometry.
Ondulin is considered one of the most reliable materials and can be used even for roofs with a slope of less than 6 degrees.
Corrugated sheets cannot be laid at an angle of less than 15 degrees, however, it is advisable to treat slopes even with an acceptable slope with sealant for better waterproofing.

Assembly technology

Before installing the roof frame, it is necessary to calculate the parameters of its elements, based on calculating the total load on the structure, and also create detailed drawing, reflecting its results.

Having a frame diagram in front of you, it is much easier to carry out high-quality installation of the rafter system of a gable roof. The technology for assembling the structure implies the following sequence:

First, the Mauerlat is laid on the upper belt of the external walls, on which the slopes will rest, and on internal partitions If the system is layered, install a bed. These elements must be firmly fixed using anchor bolts or studs.
Then the rafters are fastened. They are fixed with nails to the Mauerlat, and are also connected to each other using a metal plate. It is worth remembering that the rafters are cut to fit the mauerlat timber, and not vice versa. First, the rafters located on the edge are installed in order to set the level along which the remaining pairs will be aligned.
After installing the rafters, you should install auxiliary supporting elements that will support them - struts, tie rods, tie rods. To fix the crossbar more reliably, its end is made with a protrusion half the thickness of the beam and it is cut to the rafters, fixing it with nails in several places.
A sheathing is nailed over the rafter legs, onto which the roofing material is fixed. The material and pitch of the sheathing are selected in accordance with the characteristics of the roofing material and the slope of the roof.

Remember that a well-designed and high-quality rafter system is the key to the strength, reliability and durability of a gable roof. Therefore, do not neglect the help of professional roofers and designers when creating a roofing design for your home.

Assemble the rafters of the two roof slopes. Review of the existing gable roof rafter scheme