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 gable system there are 2 of them. Minimum thickness rafter leg 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 stand is placed only in the center, and supports the skate. For large roof sizes, as well as in houses with a 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 big role does not play.
	Asymmetrical system. Asymmetry is good not only for its original appearance; 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 is broken and classical designs 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 of the total load is taken by the wall.

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 covering 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 in the region. SNiP 2.01.07-85 will help you here; according to it, in Russia the 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 The angle of inclination is equal to or exceeds 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 fastening the Mauerlat, then comes the laying of 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 made of 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 the upper beam (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 this case, the installation of the Mauerlat was carried out on a built-in threaded pin; the pin was locked from above 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. Vertical racks are installed first on the Mauerlat. 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. On the reverse side of the rafter leg, exactly the same stand with a corner is installed. 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. We did not install central pillars, 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?

The roofing pie pattern on all pitched roofs is similar, but the installation technology and sequence of actions may be slightly different. 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 for a cold attic, and then (when money and time appear) insulate everything yourself.

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 placed under the metal tiles with a gap of about half a meter, and if you have ceramic tiles, then you need to focus on the sizes of the plates.

Insulating the roof from the inside is also easy. Plates mineral wool 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 the beginning home handyman. 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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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 construct 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.

In the construction of the rafter frame for pitched roofs use wooden and metal beams. 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 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.

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.

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, a waterproofing layer made of roofing felt, waterproofing material, etc. is required.

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.

Roof frame rafters wooden houses rest on the upper crown or on 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 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.

You can find it on our website, which may also help you a lot during construction.

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 the run - wooden beam, resting on racks 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 in use.

If the attic is cold and there is no intention of organizing useful rooms in it, 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 purlin must be clearly horizontal, but the location of the listed elements in the same plane is not necessary.
We process everything wooden parts structures before installation with fire retardants and antiseptics.
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” the contour of the building by 50 cm. If you plan to organize a canopy, separate mini-rafters are installed under it.

Another useful video about building a gable rafter base with your own hands:

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 overlays. 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

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 hanging attic structure is 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, planks, mauerlat, headstocks, racks, grade 2 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.

Video instruction on the installation of a hanging category truss structure:

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.

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 of 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. Using wooden beam It will be necessary to provide intermediate racks, which are located 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:

device monolithic belt along the edges 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 of trusses on the ground, after which they are lifted onto the roof and secured.

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 is necessary to use 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. In the case of a frame building, the support for the rafter legs is the upper frame of the 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. TO lightweight concrete include materials such as foam concrete, slag concrete, 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 - one row before the walls are cut, they insert into the masonry from the outside wooden blocks, impregnated with antiseptic. 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 the strapping beam, in the second, a special board 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 and various buildings for domestic and commercial purposes. In industrial and commercial enterprises, a gable roof is installed on buildings for various purposes that 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 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 step size mainly depends on the plumb line 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 using anchor bolts or other reliable means. 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 wide range of different 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 slightly less than the size of the 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 edged lumber for the device. 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 with protective materials against 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. The assembled structure of struts and ties is 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. The load from the corner connection of the roof rafters is distributed through the racks to 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.

To make additional parts, 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 tightening. 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 an attic in the attic space.

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) is a gable rafter system used for constructing roofs 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 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 options for installing hanging systems have been developed. Most are used for relatively small buildings without load-bearing structures inside 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 constructing 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 with any of available ways and fix the ridge on the 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.

The technology for installing gable roofs is simple; everything can be done with your own hands. 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 duties are the formation of smooth planes for laying the covering 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 is needed about the rules and principles of its design. The information is useful both for those who construct 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

Wooden and metal beams are used to construct the rafter frame for pitched roofs. 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 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 make nodal connections you will not need a welding machine or welder skills.

Rafters - a fundamental element

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, what interests us now is specifically the structure of the rafter system of a 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, a waterproofing layer made of roofing felt, waterproofing material, etc. is required.

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 cross-section and linear dimensions of wooden beams be 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.

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 laying clay tiles, for example, the optimal distance between the rafters will be 0.6-0.7 m, and for installing metal tiles and corrugated sheets, 1.5-2.0 m is acceptable. However, even if the pitch is exceeded, which is required for proper installation of the roof, 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.

Rafter structures of layered type

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 in use. If the attic is cold and there is no intention of organizing useful rooms in it, 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 purlin 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.

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.

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.

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 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 hanging attic structure is 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, planks, mauerlat, headstocks, racks, grade 2 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.

There are actually many more methods for constructing rafter systems for roofs with two slopes. We have described only the basic varieties, which in reality are 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

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 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

A gable roof consists of two inclined surfaces that have 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 internal 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 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. The struts and ties form a strong structure called a truss. 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 the external walls are located at a distance of less than 10 m. Also, between them there should no longer be walls that divide the space of the 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 the arrangement attic floor.

Layered rafters in their design have a support beam, which is placed in the middle. It is responsible for transferring the weight of the entire roof to the intermediate columnar support or middle wall located between 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 quality protection roofing covering.
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, in the amount of necessary 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, a 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 up the weight of each layer of the “pie” - thermal insulation, vapor barrier and waterproofing materials, rafter system, sheathing and the 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 the 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

The best option for a gable roof rafter system is a combination of inclined and hanging rafters. This design allows you to create a reliable gable roof and reduce costs Construction Materials. Consider the following recommendations when working:

Use only the highest quality wood as material. Beams that have cracks and knots should absolutely not be used.
The rafters have standard dimensions - 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 will not be 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. Also suitable mounting plates made of metal. 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 light, install 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 linings and metal fastening methods for this. 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 applies to 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 between rafters thermal insulation material, 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, 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

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

Design of a gable roof truss system

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

Gable roof diagram

Now about the components of the system and their purpose:

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

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

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

The difference in the design of layered and hanging rafters

With hanging rafters

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

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

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

Gable roof rafter system for small houses

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

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

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

Ridge knot and fastening of rafter legs to the backing board with a simple version of the system

For mansard roofs

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

Rafter system of a gable roof with a raised tightening and a crossbar insertion unit

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

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

For large houses

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

Gable roof rafter system for a large span and ridge and rafter insertion units

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

Straight and oblique cut for connecting the tie

For reliable joining, the connection point is reinforced with a steel plate mounted on bolts. Its dimensions should be more sizes notches - the outermost bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the notch.

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

Fastening struts for a rafter system with hanging rafters

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

Read how an attic roof works (with drawings and diagrams) here.

With layered rafters

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

The simplest version of layered rafters

Non-thrust schemes and notch units

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

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

A simple non-braced gable roof system with layered rafters

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

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

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

Option for attaching rafters without bracing to walls

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

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

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

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

Options for rafter systems with contractions

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

Schemes of rafter systems for gable roofs with contractions

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

Attaching the screed to the rafters and ridge beams

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

Read how to make a gable roof (photo report) here.

Layered rafter systems with struts

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

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

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

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

Rafter system with off-center vertical girder

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

System for houses with two internal load-bearing walls

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

Systems with rafter beams

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

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

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

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

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

Rafter structures for gable roofs

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 make nodal connections you will not need a welding machine or welder skills.

Rafters - a fundamental element

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.

Subtleties of fastening rafter legs

How to do without mind-boggling calculations?

On our website you can find a calculator for calculating a gable roof, which may also help you a lot during construction.

Rafter structures of layered type

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.

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 purlin 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.

Another useful video about building a gable rafter base with your own hands:

Hanging rafter systems

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.

Subtleties of long-span hanging systems

Hanging type for attics

A noticeable disadvantage of the hanging attic structure is 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.

Video instruction on the installation of a hanging category truss structure:

Design options Rafter systems

Layered or hanging
Expansion or non-expansion
Mounting methods

Modern buildings sometimes amaze our imagination with the most unusual shapes roofs They owe their stylish and impressive appearance to the variety of rafter structures. However, all of them are “assembled” in the skillful hands of an architect-designer, like a construction set connected in a certain order from standard elements.

Design options

Rafter systems for pitched roofs depend on their features.

Single-pitch – the simplest option in production. The peculiarity of its design is the absence of a ridge, racks and struts. Such roofs, as a rule, cover buildings with spans of 6–8 meters. Despite the simplicity of the design, with a reasonable approach, such simple design has its advantages. For example, on the south side, facing north, you can install quite big windows. This is the most convenient rafter system for an extension, garage, etc., especially since it allows you to “assemble” the roof from large sheet materials.

Another simple and cheap design is considered to be gable. However, it is not without its drawbacks. For example, in regular roof This type has too little space for an attic.

hip- not two, but four slopes. From a certain angle, it resembles an ordinary gable roof. However, its slopes do not completely cover the surface of the house - the remaining space on the sides is covered with lateral triangular hips. Thus, the roof turns out to be hipped and two types of rafters are used for its construction.

Multi-forceps- this is a structure that seems to consist of a set of gable roofs with multi-directional ridges. The rafter system of such roofs is the most expensive, but it makes it possible to arrange additional space in the attic.

Tent, thanks to its pyramid-like shape, is maximally resistant to wind loads. Moreover, snow does not linger on it. And this despite the fact that her rafter system is one of the simplest. True, the absence of gables does not allow even a small room to be equipped in the attic.

Rafter systems

Layered or hanging

The frame for the device consists of triangular-shaped elements, due to which, even when experiencing a large number of variable loads, the structure does not lose rigidity. Rafter systems of pitched roofs are divided into hanging and layered.

The choice of this or that type or method of fastening is based on the following parameters:

the dimensions of the building itself;
slope and shape of the roof;

Layered rafters

For buildings with a single- or gable roof, the use of layered rafters is more typical. This is a structure assembled from short beams or boards, having two or three rigid fastening points. In the first option, these are the walls of the building; in the case of a gable, a ridge is added, and the ridge beam in this case must be reinforced with racks. The latter are supported by beds. The length of the rafters in buildings with large dimensions exceeds 6 m. It is quite possible that additional supporting structures will need to be installed here. For example, build capital walls or columnar supports inside.

Hanging

This design is characterized by the absence of intermediate supports. Such rafters often cover spans exceeding 7 m. The wall remains the only support point for the rafter leg. As for the second end, in this case the upper parts of the rafter beam and the oncoming leg are joined. For this they use various ways: by means of a slotted tenon or metal plates, a half-wood connection.

Expansion or non-expansion

The reliability of the roof is primarily ensured by a careful calculation of the loads under which its frame is exposed. The rafters become, as it were, “conductors” of these loads on the external supports of the structure. The load that rafter legs exert on their supports can be of two types - spacer and non-spacer.

Spacer

The rafter beams in this design work in compression and bending, which causes a significant horizontal expansion force. It is naturally transferred to the walls. When installing a horizontal tightening, it will take on this thrust and this force will decrease. This farm element performs several functions:

connects the rafters,
serves as a support for them
does not allow the bases of the beams to move apart.

The tie can be installed at the base of the rafters, then it will act as a floor beam. It can be installed higher. With such a device, the tightening is called a crossbar. For large spans, as a rule, it is necessary to complicate the design of the trusses, that is, install not only tie rods, but other additional elements.

Non-thrust

The support for the lower ends of the rafter legs in this system are:

walls, and their upper ends are connected to each other by a purlin, which, in turn, rests on racks or
support frames formed by upper and lower purlins, racks and struts

The elements of the system function like beams, that is, exclusively in bending.

Mounting methods

Thrustless systems. Rafters of this type are installed so that one support turned out to be fixed, and the other - movable, and both of them should be able to rotate freely. In practice, there are three ways to eliminate dangerous loads acting on the walls in this case. The lower end of the rafter leg rests against the mauerlat. It is hemmed with a block and fixed using a notch with a tooth. It is also advisable to additionally insure the fastening with wire. The upper part of the beam is mounted on the ridge girder. For fastening, the principle of sliding support is used. An example would be the rafter system of a veranda.

The bottom of the rafter is fixed using a movable joint. To fix the top part after laying it on the ridge girder, use a bolt, nails, etc. This is the most common option for gable roofs.
Rigid fastening to the purlin using nails, pins or other fasteners.

In any embodiment, the following principle is observed: at one end the rafter leg is fixed on a support that operates on the sliding principle, allowing rotation, and at the other - on a hinge, allowing only rotation.

Spacers. Both supports, unlike non-thrust ones, are fixed. The installation is carried out according to the same construction schemes, only in this case the lower supports are fixed not to sliders, but to a hinge allowing one degree of freedom. You can nail support bars about a meter long to the bottom of the rafters, or attach the support to the Mauerlat with a “tooth”.

For small, lightweight roofs, it is possible to install them without a Mauerlat, but it should be taken into account that in this case the load is distributed unevenly along the wall.

A gable roof or gable roof is a roof with two slopes, i.e. having 2 inclined surfaces (slopes) of a rectangular shape.

Due to its design features, the frame of a gable roof ideally combines simplicity of design and maintenance with reliability and durability. These and many other parameters make the construction of a gable roof a practical and rational solution for private and commercial housing construction.

In this article, we will look at how to make a rafter system for a gable roof with your own hands. For effective perception of the material, it is presented in the form of step-by-step instructions from A to Z, from selection and calculations, to installation of the Mauerlat and sheathing under the roof. Each stage is accompanied by tables, diagrams, drawings, drawings and photos.

The popularity of the house roof is due to a number of advantages:

design variability;
simplicity in calculations;
naturalness of water flow;
integrity of the structure reduces the likelihood of leaks;
efficiency;
preserving the usable area of the attic or the possibility of arranging an attic;
high maintainability;
strength and wear resistance.

Types of gable roof

The installation of a gable roof truss system depends, first of all, on its design.

There are several options for gable roofs (types, types):

1. Simple gable roof - symmetrical

A simple gable roof is symmetrical. The most common roof design option due to its simplicity and reliability. Thanks to symmetry, a uniform distribution of loads on the load-bearing walls and mauerlat is achieved. The type and thickness of the insulation does not affect the choice of material.

The cross-section of the beam makes it possible to provide a reserve of bearing capacity. There is no possibility of rafters bending. Supports and spacers can be placed almost anywhere.

An obvious drawback is the impossibility of arranging a full-fledged attic floor. Because of sharp corners“dead” zones appear that are unsuitable for use.

2. Simple asymmetrical gable roof

Simple asymmetrical gable roof The construction of one angle of more than 45° leads to a reduction in the amount of unused area. There is an opportunity to do living rooms under the roof. At the same time, the requirements for calculations increase, because the load on the walls and foundation will be distributed unevenly.

3. Broken gable roof, with external and/or internal fracture

Broken gable roof, with an external and/or internal break. This roof design allows you to equip a full second floor under the roof.

Naturally, a simple gable rafter roof differs from a broken roof, not only visually. The main difficulty lies in the complexity of the calculations.

Design of a gable roof truss system

Building a roof of any complexity with your own hands requires knowledge of the purpose of the main structural elements.

The locations of the elements are shown in the photo.

Elements of a gable roof rafter system Elements of a gable roof rafter system - diagram 2
Elements of a gable roof rafter system - diagram 3

Mauerlat. Designed to distribute the load from the rafter system onto the load-bearing walls of the building. To arrange the Mauerlat, a timber made of durable wood is selected. Preferably larch, pine, oak. The cross-section of the beam depends on its type - solid or glued, as well as on the expected age of the structure. The most popular sizes are 100x100, 150x150 mm.
Advice. For a metal rafter system, the Mauerlat must also be metal. For example, a channel or an I-profile.

Rafter leg. The main element of the system. To make rafter legs, a strong beam or log is used. The legs connected at the top form a truss.

The silhouette of the roof truss defines appearance buildings. Examples of farms in the photo.

Roof truss system options

The parameters of the rafters are important. They will be discussed below.

Puff- connects the rafter legs and gives them rigidity.

Run:

Ridge run, is mounted at the junction of one rafter to another. In the future, the roof ridge will be installed on it.

Side purlins, they provide the truss with additional rigidity. Their number and size depend on the load on the system.

Rafter stand- vertically located beam. It also takes on part of the load from the weight of the roof. In a simple gable roof it is usually located in the center. With a significant span width - in the center and on the sides. In an asymmetrical gable roof, the installation location depends on the length of the rafters. With a broken roof and arrangement of one room per attic attic– the racks are located on the sides, leaving free space for movement. If there are supposed to be two rooms, the racks are located in the center and on the sides.

The location of the rack depending on the length of the roof is shown in the figure.

Rack location depending on roof length

Strut. Serves as a support for the stand.

Advice. Installing the brace at an angle of 45° significantly reduces the risk of deformation from wind and snow loads.

In regions with significant wind and snow loads, not only longitudinal struts are installed (located in the same plane as the rafter pair), but also diagonal ones.

Sill. Its purpose is to serve as a support for the rack and a place for attaching the strut.

Lathing. Designed for movement during construction work and fixation of roofing material. Installed perpendicular to the rafter legs.

Advice. An important purpose of the sheathing is to redistribute the load from the roofing material to the rafter system.

Having a drawing and diagram indicating the location of all the listed structural elements will help in the work.

Advice. Be sure to add information about the passage of the ventilation shaft and chimney to the gable roof rafter system diagram.

The technology of their installation is determined by the type of roof.

Selection of material for rafters

When calculating the material for a gable roof, you need to choose high-quality wood without damage or wormholes. The presence of knots for beams, mauerlat and rafters is not allowed.

For sheathing boards, there should be a minimum of knots, and they should not fall out. The wood must be durable and treated with the necessary preparations that will increase its properties.

Advice. The length of the knot should not exceed 1/3 of the thickness of the timber.

Calculation of the rafter system of a gable roof

Calculating the material parameters is an important step, so we present the calculation algorithm step by step.

Calculation of the rafter systemIt is important to know: the entire rafter system consists of many triangles, as the most rigid element. In turn, if the stingrays have different shape, i.e. are an irregular rectangle, then you need to divide it into separate components and calculate the load and amount of materials for each. After calculations, summarize the data.

1. Calculation of the load on the rafter system

The load on the rafters can be of three types:

Constant loads. Their action will always be felt by the rafter system. Such loads include the weight of the roof, sheathing, insulation, films, additional roofing elements, and finishing materials for the attic floor. The weight of the roof is the sum of the weight of all its constituent elements; such a load is easier to take into account. On average, the constant load on the rafters is 40-45 kg/sq.m.

Advice. To make a safety margin for the rafter system, it is better to add 10% to the calculation.

For reference: The weight of some roofing materials per 1 sq.m. presented in the table

Advice. It is desirable that the weight of roofing material per 1 sq.m. roof area did not exceed 50 kg.

Variable loads. Valid in different periods and with different strengths. Such loads include: wind load and its strength, snow load, precipitation intensity.

In essence, the roof slope is like a sail and, if you take into account the wind load, the entire roof structure can be destroyed.

Wind load on the roof

The calculation is carried out according to the formula: wind load is equal to the regional indicator multiplied by the correction factor. These indicators are contained in SNiP “Loads and Impacts” and are determined not only by the region, but also by the location of the house. For example, on a private house surrounded by multi-story buildings, there is less load. Standing separately Vacation home or the cottage experiences increased wind loads.

2. Calculation of snow load on the roof

The roof calculation for snow load is carried out according to the formula:

The total snow load is equal to the weight of the snow multiplied by the correction factor. The coefficient takes into account wind pressure and aerodynamic influence.

The weight of snow that falls on 1 square meter. roof area (according to SNiP 2.01.07-85) is in the range of 80-320 kg/sq.m.

Coefficients showing the dependence on the slope angle are shown in the photo.

Scheme for calculating the snow load on the roof

Nuance. When the slope angle is over 60 ° the snow load does not affect the calculation. Because the snow will quickly slide down and will not affect the strength of the beam.

Special loads. Accounting for such loads is carried out in places with high seismic activity, tornadoes, and storm winds. For our latitudes, it is enough to make a safety margin.

Nuance. The simultaneous action of many factors causes a synergy effect. This is worth considering (see photo).

Assessment of the condition and load-bearing capacity of walls and foundations

It should be borne in mind that the roof has significant weight, which can cause damage to the rest of the building.

Determining the roof configuration:

simple symmetrical;
simple asymmetrical;
broken line

The more complex the shape of the roof, the greater the number of trusses and rafter elements needed to create the necessary safety margin.

3. Calculation of the roof angle

The angle of inclination of a gable roof is determined primarily by the roofing material. After all, each of them puts forward their own demands.

soft roof – 5-20°;
metal tiles, slate, corrugated sheets, ondulin - 20-45°.

It should be noted that increasing the angle increases the area of space under the roof, but also the amount of material. What affects the total cost of work.

Calculation of roof slope angle

Nuance. The minimum angle of inclination of a gable roof must be at least 5°.

5. Calculation of rafter pitch

The pitch of the gable roof rafters for residential buildings can be from 60 to 100 cm. The choice depends on the roofing material and the weight of the roof structure. Then the number of rafter legs is calculated by dividing the length of the slope by the distance between the rafter pairs plus 1. The resulting number determines the number of legs per slope. For the second, the number must be multiplied by 2.

6. Calculation of the length of the roof rafters

The length of the rafters for the attic roof is calculated using the Pythagorean theorem.

Parameter "a"(roof height) is set independently. Its value determines the possibility of arranging a living space under the roof, the convenience of being in the attic, and the consumption of material for the construction of the roof.

Parameter "b" equal to half the width of the building.

Parameter "c" represents the hypotenuse of the triangle.

Advice. To the obtained value you need to add 60-70 cm for cutting and moving the rafter leg beyond the wall.

It is worth noting that maximum length timber - 6 m.p. Therefore, if necessary, the timber for the rafters can be spliced (extension, joining, joining).

The method of splicing rafters along the length is shown in the photo.

Methods for splicing rafters along the length

The width of the roof rafters depends on the distance between opposite load-bearing walls.

7. Calculation of the rafter cross-section

The cross-section of the rafters of a gable roof depends on several factors:

loads, we have already written about it;

type of material used. For example, a log can withstand one load, timber – another, laminated timber – a third;

rafter leg lengths;

the type of wood used in construction;

distances between rafters (rafter pitch).

You can determine the cross-section of the beam for the rafters, knowing the distance between the rafters and the length of the rafters using the data below.

Rafter cross-section - table

Advice. The larger the installation pitch of the rafters, the greater the load on one rafter pair. This means that the cross-section of the rafters needs to be increased.

Dimensions of lumber (timbers and boards) for a gable rafter system:

thickness (section) of the Mauerlat – 10x10 or 15x15 cm;

the thickness of the rafter leg and tie is 10x15 or 10x20 cm. Sometimes a beam of 5x15 or 5x20 cm is used;

run and strut - 5x15 or 5x20. Depending on the width of the foot;

stand – 10x10 or 10x15;

bench – 5x10 or 5x15 (depending on the width of the rack);

thickness (section) of the roof sheathing – 2x10, 2.5x15 (depending on the roofing material).

Types of gable roof rafter system

For the roof structure under consideration, there are 2 options: layered and hanging rafters.

Types of roof systems: with layered and hanging rafters

Let's consider each type in detail in order to make an informed choice.

Hanging rafters

They are used for roof widths of no more than 6 lm. Installation of hanging rafters is carried out by attaching the legs to the load-bearing wall and the ridge girder. The design of hanging rafters is special in that the rafter legs are under the influence of a bursting force. Hanging rafters with a tie installed between the legs reduce its impact. The tie in the rafter system can be wooden or metal. Often the ties are placed at the bottom, then they play the role of load-bearing beams. It is important to ensure that the tie is securely attached to the rafter leg. Because a bursting force is also transmitted to it.

Advice.
The higher the tightening is located, the greater strength it should have.
If the tightening is not installed, the load-bearing walls may simply “move apart” from the pressure created by the rafter system.

Layered rafters

They are used for arranging roofs of any size. The design of layered rafters provides for the presence of a beam and a stand. The bench lying parallel to the Mauerlat takes on part of the load. Thus, the rafter legs are, as it were, inclined towards each other and supported by a stand. The rafter legs of the layered system work only in bending. And the ease of installation also tips the scales in their favor. The only drawback is the presence of a stand.

Combined

Due to the fact that modern roofs are distinguished by a wide variety of shapes and complexity of configurations, a combined type of rafter system is used.

Combined view of the rafter system

After choosing the type of rafter system, you can accurately calculate the amount of materials. Write down the calculation results. At the same time, professionals recommend drawing up drawings for each roof element.

Installation of a gable roof rafter system

After the gable roof rafters have been calculated, installation can begin. We will divide the process into stages and give a description of each of them. The result will be a kind of step-by-step instructions containing additional information on each stage.

1. Attaching the Mauerlat to the wall

The beam is installed along the length of the wall on which the rafters will rest.

In log houses, the role of the mauerlat is played by the upper crown. In buildings built from porous material (aerated concrete, foam concrete) or brick, the Mauerlat is installed along the entire length of the load-bearing wall. In other cases, it can be installed between the rafter legs.

Material prepared for the website www.moydomik.net

Splicing the Mauerlat with each other (direct lock with bolts) Since the length of the Mauerlat exceeds the standard dimensions of lumber, it has to be spliced.

The connection of the Mauerlat to each other is done as shown in the figure.

How to connect the Mauerlat?

The beams are cut only at an angle of 90°. Connections are made using bolts. Nails, wire, and wooden dowels are not used.

How to attach the Mauerlat?

The Mauerlat is installed at the top of the wall. The installation technology provides several ways to attach the Mauerlat:

strictly in the center of the load-bearing wall;
with a shift to one side.

Advice.
The Mauerlat cannot be placed closer than 5 cm to the outer edge of the wall.

To protect the timber for the Mauerlat from damage, it is laid on a layer of waterproofing material, which most often is ordinary roofing felt.

Reliability of Mauerlat fastening important aspect construction. This is due to the fact that the roof slope is like a sail. That is, it experiences strong wind load. Therefore, the Mauerlat must be firmly fixed to the wall.

Methods for attaching the Mauerlat to the wall and rafters

Fastening the Mauerlat with anchors Anchor bolts. Ideal for monolithic structures.

Fastening the Mauerlat with wooden dowelsWooden dowels. Used for log houses and beams. But, they are always used with additional fasteners.

Fastening the Mauerlat with staples. Staples.

Fastening the Mauerlat to studs or fittings Stud or fittings. It is used if the cottage is built from porous materials (aerated concrete, foam concrete).

Fastening the Mauerlat with a sliding fastening Sliding fastening (hinged). Tying in this way allows for the displacement of the rafter legs when the house shrinks.

Fastening the Mauerlat with wire. Annealed wire (knitting, steel). Used as an additional mount in most cases.

2. Manufacturing of trusses or pairs

Installation is carried out in two ways:

installation of beams directly on the roof. It is not used often, since it is problematic to carry out all the work, measurements, and trimming at height. But it allows you to completely do the installation yourself;

assembly on the ground. That is, individual elements (triangles or pairs) for the rafter system can be assembled below and then raised to the roof. The advantage of such a system is faster performance of high-altitude work. The disadvantage is that the weight of the assembled truss structure can be significant. To lift it you will need special equipment.

Advice. Before assembling the rafter legs, you need to apply markings. It is very convenient to use templates for these purposes. The rafter pairs assembled according to the template will be absolutely identical. To make a template, you need to take two boards, the length of each of which is equal to the length of one rafter, and connect them together.

3. Installation of rafter legs

The assembled pairs rise to the top and are installed on the Mauerlat. To do this, you need to make a gash at the bottom of the rafter legs.

Advice. Since the slots on the Mauerlat will weaken it, you can only make cuts on the rafter leg. To ensure that the cut is uniform and fits tightly to the base, you need to use a template. It is cut out of plywood.

Methods of fastening the rafter leg are shown in the figure.

Methods for attaching a rafter leg

You need to start installing rafter pairs from opposite ends of the roof.

Advice. To correctly install the rafter legs, it is better to use temporary struts and spacers.

A twine is stretched between the rafter pairs. A twine is stretched between the fixed pairs. It will simplify the installation of subsequent rafter pairs. It will also indicate the level of the ridge.

If the rafter system is mounted directly on the roof of the house, then after installing the two outer rafter legs, the ridge support is installed. Next, the halves of the rafter pair are attached to it.

It is worth noting that the opinions of professionals differ on this issue. Some advise using a staggered fastening pattern, which will allow the increasing load to be distributed more evenly on the walls and foundation. This procedure involves installing one rafter per checkerboard pattern. After part of the rafter legs is installed, the missing parts of the pair are mounted. Others insist that it is necessary to mount each pair in a sequential manner. Depending on the size of the structure and the configuration of the truss, the rafter legs are reinforced with supports and racks.

Fixation with rafter brackets. Nuance. Additional structural elements are connected using cutting. It is preferable to fix them with construction staples.

If necessary, you can lengthen the rafter leg.

Methods for splicing rafter legs are shown in the photo.

Methods for splicing rafter legs

Advice. The method by which the mauerlat is lengthened (cut at 90°) cannot be used in this case. This will weaken the rafter.

4. Installing the ridge of a gable roof

The roof ridge unit is made by connecting the rafter legs at the top.

Roof ridge structure:

Method without using a support beam (see figure).

Installing a roof ridge without using a support beam

Method using rafter beams. Timber is needed for large roofs. In the future, it can become a support for the rack.

Method of laying on timber.

Installing a roof ridge using the overlay method
Installing a roof ridge using the overlay method

More modern variety The method shown in the photo can be considered for making a ridge assembly.

Method for making a ridge knot

Cutting method.

Installing a roof ridge using the cutting method

After the rafter system is installed, we perform major fastening of all structural elements.

5. Installation of roof sheathing

The sheathing is mounted in any case, and is designed for more convenient movement along the roof during the work process, as well as for fastening roofing material.

The sheathing pitch depends on the type of roofing material, for example:

for metal tiles - 350 mm (the distance between the two lower boards of the sheathing should be 300 mm).
for corrugated sheets and slate – 440 mm.
We lay a continuous sheathing under the soft roof.

Rafter system of a gable roof with an attic - video:

Conclusion

As you can see, despite its apparent simplicity, the installation of a gable roof rafter system contains many pitfalls. But, based on the recommendations given, you can easily build a reliable structure with your own hands.

Tags: Roof Gable roof Rafters

21.02.2017 1 Comment

The rafter system of a gable roof is a simple design that can be installed with your own hands even by a novice developer. You just need to make preliminary calculations, familiarize yourself with the details and stages of roof construction, and calculate the materials needed for installation. When making calculations, it should be taken into account that the load-bearing capacity of a gable roof depends on the influence of loads from wind, snow, and the weight of materials on it.

To make the process of building a gable roof rafter system as easy as possible for you, below is detailed step-by-step instructions for installing a rafter system with your own hands.

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Requirements for building materials

For the installation of a rafter system, the best option would be to use lumber from coniferous wood - pine, spruce or larch, grades I - III.

The material for the rafters is taken at least grade II, the mauerlat is made from boards or timber of grade II, material of grade II is taken for racks and purlins, the sheathing is made from lumber of grades II-III, it depends on the roof. Crossbars and tie-downs are made of Grade I material. Grade III material can be used on linings and linings.

Note! The lumber must be dry with a moisture content of no more than 20%. It should be treated before installation fire retardant compounds and antiseptics against fungal diseases.

Lumber should be stored under a canopy, providing protection from the sun and moisture. Level the storage area and cover the lumber with pads for ventilation.

For installation you will need fastening elements: ties, plates, studs, bolts with washers and nuts, self-tapping screws with EPDM gaskets, 2.8 mm thick, mounting tape, galvanized brackets.

Brackets are used when attaching the Mauerlat; they are secured with nails or self-tapping screws.

KR corners serve to attach the rafters to the mauerlat and prevent the rafters from moving.

All fastening material must be made of high quality material and be protected against corrosion.

Tools for constructing a rafter system

To install a gable roof rafter system, you will need the following set of tools:

tape measures of different lengths 5, 10, 20 meters;
markers, pencils;
cord for tensioning;
hammers, for various purposes, nail puller;
scissors, for cutting;
roofing knife;
putty knife;
scotch;
hacksaws, electric saw, electric drill with various drills and attachments;
screwdriver with attachments;
markings, horizontal and vertical levels;
slats, rulers;
polyurethane foam;
safety belt and rope - for safe work.

Keep all tools on the roof in a tool bag for safety reasons.

Types of rafter systems for a gable roof

Sent rafters

They rest on the mauerlat and racks installed on the inner wall, with a pitch equal to the rafters. To provide rigidity for spans of 6 m, additional struts are installed.

Scheme of layered rafters of a gable roof

Hanging rafters

If the building is small in width, you can arrange a rafter system where the rafters rest on the mauerlat or walls, without intermediate supports. The maximum span is 9 meters. Such roofs can sometimes be installed without a Mauerlat. The rafters are installed on the wall using spacers; in this embodiment, a bending moment acts on the rafters.

To unload, wooden or metal plates are installed. They securely strengthen the corner. For hanging rafters of a larger span, a headstock and struts are installed. For hanging systems, the rafters are made with a larger cross-section, and lumber is chosen at least grade I II.

Scheme of hanging rafters of a gable roof

Calculation of the rafter system

You can determine the cross-section of a gable roof beam required in a rafter system by collecting all the loads acting on it: the weight of the covering, sheathing, snow, wind pressure, precipitation.

Constant loads can be determined by the weight of 1 m 2 of roofing and sheathing. It is important that the weight per 1 m 2 of roofing be in the range of 40-45 kg.

Variable loads from snow and wind are calculated using table values regulatory documents SNiP, depending on the height of the building and temperature zone. The load from snow is equal to its weight multiplied by a coefficient depending on the slope of the slope. All these calculations are performed during the project.

What if there is no project and the roof is being erected on a small building? You need to look at the construction of a house in the neighborhood, which is being carried out according to a design whose roof area is the same as your building. The gable roof rafter system will serve as a model.

Dimensions of timber for rafters

At the top point a ridge is laid that connects the rafters. The height of the ridge depends on the slope of the roof. The slope is affected by the choice of coating material. Minimum dimensions are:

for tiled roofs, slate 22 gr.;
for metal tiles - 14 g;
ondulin - 6 g;
corrugated sheeting - 12 gr.

The optimal angle is 35-45 degrees. tilt, ensures rapid discharge of water and snow. In regions with strong winds, the roofs are made flat and then the angle of inclination is within 20-45 degrees.

The height can be determined using the formula: H=1/2Lpr*tgA. Where A is the angle of inclination, L is the width of the building.

The task is simplified when using a ready-made table. The coefficient depends on the width of the building and the angle of inclination. Multiply the coefficient by 1⁄2 the width of the building.

The rafters are made from pine or spruce bars, with a section of 50x100 mm, 50x150 mm.

The size of the rafters depends on the pitch. The pitch of the rafters is smaller, a larger number is installed, and the cross-section will decrease. The distance between the rafters on a gable roof ranges from 600 mm to 1800 mm, it all depends on the design of the roof and the materials used for its construction.

Table of rafter sizes, depending on the step of their installation

Length rafters, mm	Distance between rafters, mm	Rafter beam cross-section size, mm
up to 3000	1200	80×100
up to 3000	1800	90×100
up to 4000	1000	80×160
up to 4000	1400	80×180
up to 4000	1800	90×180
up to 6000	1000	80×200
up to 6000	1400	100×200

The roof does not end at the level of the walls; it is extended outward by 500 mm. The rafter leg can protrude, or a board or block can be built up. In this case, moisture does not get on the wall and the foundation is not poured.

Step-by-step installation of a gable roof truss system

The rafter system of a gable roof consists of the following elements:

Mauerlat.
Lay down.
Racks.
Rafters.
Struts.
Puffs.
Lathing.

Mauerlat installation

Fastening the Mauerlat to a monolithic reinforced concrete belt

Mauerlat evenly distributes the load on the walls of the building; its installation can be done in several ways:

attached to the wall through a reinforced concrete belt with studs;
studs are inserted into the masonry;
a simple and common method for simple roofs, fastening with wire rod.

For it, take timber with a cross section of 100×100 mm, 150×150 mm or 200×200 mm. Which section to choose depends on the size of the roof and its covering. The Mauerlat is joined along its length; to do this, make 100 mm cuts, 500 mm long, fold the bars and fasten them with pins.

In the corners, the mauerlat is tied with notches into the floor of the timber, fastened with staples or bolts. For wooden buildings, the Mauerlat is the last crown. On brick walls, make a monolithic reinforced concrete belt with a cross-section of 400×300 mm. Along the belt, place threaded pins 12 mm in diameter, every 120 mm, for fastening.

Drill holes with a diameter of 12 mm in the Mauerlat, lay them so that the pins go into the holes. Tighten the top with nuts. First, we lay two layers of roofing felt or roofing felt under the block. On the outside of the wall, lay the mauerlat with bricks. Lay the Mauerlat on a horizontally and vertically level base. You need to check with a level that the surface is horizontal. Check diagonals. If necessary, level with pads.

Installation instructions for beds, racks, rafters, struts and tie rods

The installation of a gable roof rafter system with your own hands is carried out in the following order:

Install the beam with the rafters in place.
Mark the installation step of the rafter legs.
Prepare according to the size of the rack.
Install them, if necessary, with spacers.
Lay the purlin. Check geometry. Install fasteners.
Try on the first rafter leg and mark the cutting areas.
Mark the points and install the rafters at the beginning and end of the roof, stretch the cord between them in order to align the remaining elements along it.
Having installed the rafter leg, we first attach it to the mauerlat, then to the ridge purlin, to each other.
Screw each second leg to the mauerlat with wire.

The rafters are fastened to the mauerlat using notches, stop corners and a hemmed support bar. Secure with nails or staples.

Methods for attaching rafters to the Mauerlat

Install the support posts on the beds or pads and overlays. A log is a beam 50×100 mm or 50×150 mm, laid on the middle wall along a layer of roofing felt. Place brick pillars under the linings, 2 bricks high.

The rafter legs are connected to each other at the ridge. Let's consider the common connection nodes of the rafter system:

They make cuts at one leg and cut down at the other. Insert one leg into the cut of the other and fasten with a bolt.
Install overlays, wooden or metal.
Using notches in the purlin, they are secured with nails or bolts.

Methods for connecting rafters on a ridge

To ensure the roof's resistance to wind loads, tie-rods, struts and purlins are installed. The tightening is a 100×150 mm block, purlins and struts are made from a 50×150 mm or 100×150 mm block.

With the installation of contractions, the reliability of the rafter structure increases. The sections of the timber are the same as the rafters. They are attached to the legs with bolts or nails. The device of struts adds rigidity to the structure. They are installed tightly to the surface of the rafters

The lumber has a standard length of 6 m. The rafters can be longer. Then you need to dock them. There are several connection methods:

Fasten by placing bars on both sides at the junction, connecting them with nails in a checkerboard pattern.
Connect with an overlap, one part of the rafters to another, at a distance of 1 meter, fasten with nails in an alternating order.
Make a cut obliquely, cut out part of the rafter legs, connect them, strengthening them with bolts.

Sheathing device

Lathing is installed along the roof rafters. It serves to distribute the load from roofing material and snow onto the rafters. Plays the role of an air gap between the roof and the rafter system.

The design of the sheathing depends on the roofing material used:

under the soft tiles, make the sheathing continuous, lay an anti-condensation film on the rafters, press it on top with a counter batten, nail the sheathing onto it, then OSB boards and underlayment carpet, lay the tiles on top.
Under the roof made of corrugated sheets, the sheathing should be sparse. The pitch of the sheathing depends on the brand of corrugated sheeting, its thickness and the angle of inclination of the roof.
The lathing for standard slate should be made in increments of 500 mm from a bar of 75×75 mm or 50×50, as well as boards from 30×100 mm. The design features of the roof should be taken into account when making the final choice of the appropriate option.

The lumber from which the sheathing is made is first or second grade pine. It is advisable to take the width no more than 14 cm. With a wider width, the boards may warp and damage the roofing. The length of the nails should be three times the thickness of the sheathing. Lay the boards along the ridge. Install the first board of greater thickness to the height of the roofing.

Install continuous sheathing along the roof slope.

The first layer is to place a board along the ridge from it at a distance of 500-1000 mm to the next one and so on. Lay the second layer of sheathing along the rafters. Place the joint between the boards only on the rafters at intervals. Sink the nail, head and all, into the flesh of the wood.

Cornice overhangs

They are installed to protect from precipitation and play an aesthetic role. Eaves overhangs are arranged tightly without gaps. The final stage on roofing.

Diagram of the eaves overhang of a gable roof

Gable

The gable roof has two gables. They have the shape of a triangle, with the apex at the ridge and the sides coincide with the slopes of the roof. The gables support the rafters and enclose the attic space. They protect from wind and precipitation and provide stability to the roof.

In wooden buildings, the pediment is framed. In brick buildings, frame or brick. Gables made of brick or gas block are erected before the roofing is installed. They require very precise execution.

Frame pediments fit into the finished opening when the rafter system is already assembled.

The frame is made of bars or boards. The frame elements are connected on tenons or in the wood floor, all fastened with nails. They are sheathed by nailing boards, lining or siding, maintaining the color scheme in the decoration of the building facade. To construct a window opening, an additional frame is made under it according to the size of the window. If the attic is insulated, then the gable also needs to be insulated. The insulation is placed in the middle of the frame. Mineral wool insulation with reduced flammability is used. On the outside, the frame is covered with a hydro-windproof film or windproof membrane, with inside under finishing material nail a vapor-proof film or a vapor-proof membrane.

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