Do-it-yourself wooden rafters for a gable roof. The design of the gable roof truss system

A gable roof is used for various wooden houses. You can even assemble the structure with your own hands, as it is simple, unlike a four-slope or attic. The main building materials for installation are boards and beams made of timber or logs. After reading the article to the end, readers will find out what are the main elements of a gable roof frame, and how to assemble it with your own hands and calculate the cross section and length of the beams. Pro .

The truss system of a gable roof for the construction of a house from a bar consists of: a rafter leg, a mauerlat, a filly, a ridge, struts, racks and a crate. In order to assemble with your own hands, you need to represent the design in full. We will discuss each element in more detail below.

Mauerlat

Mauerlat is the main load-bearing part of the gable roof frame structure. It consists of a beam located around the entire perimeter of the house, on load-bearing walls. Under the construction of a house from glued beams or other types of lumber, it is fastened with binding and metal brackets.

Through the Mauerlat, the load from the entire rafter system is transferred to the load-bearing walls of the house. The size of the Mauerlat for a wooden house is 100x100 mm or 150x150 mm. Coniferous wood is used for this knot. Before laying, the timber is treated with an antiseptic and waterproofed with a bituminous tape.

rafter leg

The main contour of the future roof is assembled from the rafter legs. For the roof frame of a wooden house, a material with a section of 50x150 or 100x150 mm is used. The rafter legs are laid in the shape of a triangle. The entire system rests on the rafter legs, and it depends on the quality of the material whether the roof can withstand wind and snow loads.

The weight of the entire roof structure is transferred through the legs to the Mauerlat. Rafter legs are mounted in increments of 60-120 cm, depending on the severity and fastening of the future roof. The heavier it is, the more often the step of mounting the legs of the truss system.

Skate

A ridge is a connecting beam of two rafter parts of a slope in the upper part. It is mounted strictly horizontally at the connection of the legs.

For a wooden gable roof, a bar with a section of 100x100 mm is used as a ridge. It is pre-treated with an antiseptic.

Filly

The filly is an element that plays the role of a roof overhang. This part is attached to the rafter leg if its length is not enough to form an overhang of at least 200 mm. If the rafter leg is enough, then you can not mount the filly.

For mounting, boards of a smaller size and section than the legs are used. The filly makes the installation of the frame easier, since the beams for the legs no longer need a large length. If the roof is assembled by hand, then experts recommend choosing this option.

Sill

This is a bar, which is placed horizontally on the internal load-bearing walls of the log house. The main load from the racks of the truss system falls on the bed, and he transfers it to the supporting wall.

The installation uses a material with a cross section of 100x100-150x150 mm.

Racks

Drains are attached vertically from the ridge to the internal load-bearing wall. For their manufacture, a material with a section of 100x100-150x150 mm is used after calculations. In the rafter system, they play the role of redistributing the load from the ridge to the load-bearing wall.

Puffs

Puffs connected to the legs of the frame have the shape of a triangle. It is a fastener in the system. It is thanks to the puffs that the legs do not scatter in different directions under the pressure of the structure and roof.

Struts

Struts consist of pieces of boards mounted at an angle. With the help of struts, the load from the rafter legs is redistributed to the load-bearing walls. In connection with puffs, the struts form trusses. The farm consists of several struts and one puff. They use trusses to transfer the load if the spans are too large.

crate

Roof sheathing device

They make a crate from boards or not thick bars. In the rafter system, the crate is attached perpendicular to the legs to them. With the help of the crate, the load from the roof structure (roof, insulation, vapor barrier -) is evenly distributed over all rafter legs. Another function of the crate is the connection of the rafter legs to each other into a single system. Even a non-edged board is suitable as a crate. But first you need to peel off the bark from it.

If the roof is rolled, for example, bituminous, then instead of boards, sheets of plywood are used as battens. So the substrate under the roof acquires a hard and even surface, on which it is easy to roll out the same roofing material.

All of the listed parts of the frame of the gable structure are dried and treated with antiseptic impregnations before installation, you can do it yourself. Otherwise, the truss system will quickly rot.

What is the truss system for a gable roof

The contraction of the rafters for a gable roof for the construction of a house from profiled timber can be used strung or hanging.

Hanging structure

This system has a structure based on the side load-bearing walls of the log house. But at the same time, the rafters interact negatively with the walls, bursting them. To avoid this, in the frame of a gable roof, the legs are pulled together with special puffs. The drawstrings and legs form a triangular mount that has rigid ribs and the structure does not deform over time.

In the truss structure, floor beams can play the role of puffs. So the design can be used as an attic. For greater strength, a puff of at least 50 cm from the roof ridge is also installed on top of the rafter part.

It is necessary to make such a design if the span between the load-bearing walls of the log house is not more than 10 cm. If this span is larger and there is a load-bearing wall between it that divides it in half, then the hanging system can be mounted

Layered structures

The layered rafter system is installed on a log house with any span. Its feature is in the support beam, which is located in the middle in the span of the walls. It is advisable to use such a design when the distance between the bearing walls is more than 10 m.

If there is a load-bearing column between the main load-bearing walls, then you can use the attic version of the layered rafters. In this case, the rafters will be attached to the column, and additional rafters will be made between the columns. But to do it without certain skills is difficult.

How to calculate roof rafters

Before you start making a roof frame with your own hands, you need to calculate the length and thickness of the beams.

Calculation of the section of beams

The cross section of the rafter beams is directly related to their length and fastening pitch. To determine the ratio of these indicators, there are special calculators with which it is not difficult to calculate and GOSTs.

Calculation of the ratio of the length and section of beams in the form of a table:

Rafter beam length, m	Cross section of the material used, mm		Rafter step, m
	Beam or board	Log
From 1-3	80x100, 90x100, 90x160	100, 150, 160	1 – 1,35
From 3-4	80x160, 80x180, 90x180	160, 180	1,40 – 1,70
From 4-5	80x200, 100x200	200	1,40 – 1,75
From 5-5.8	100x200	200	1,10 – 1,40
From 5.9-6.5	120x220	240	1,10 – 1,40

Judging by the numbers, if the length of the rafters is large, then the distance between them decreases, and the cross section increases. If you take rafters of a smaller section and do not make the necessary calculation, then over the years the roof will sag.

Saw off beams - legs after the calculation is made, you need to have the same length and mount each pair on this straight line.

Subtleties of mounting a gable roof

The main stages of building a roof frame with your own hands consist of:

1. Mauerlat mount
2. Installation of rafter legs
3. Mounting the skate
4. Bundle of legs
5. crate

How professionals do the installation of the roof can be seen on the provided video:

On the video you can see the finished frame from the timber and its description, each node clearly. Readers will find Mauerlat, rafter legs, their fastening, etc. on the video.

Mauerlat mount

In wooden houses, you can not mount an additional Mauerlat. Its role will be played by the upper log or timber. But if the roof structure should be higher, then you need to bind the timber.

The laying of the timber begins with its insulation; for this, the walls are covered from above with a double layer of roofing material. The bar is processed and stacked. In the corners it is connected with their own hands with the help of metal staples and cuts in half the section.

Mauerlat is placed strictly parallel to the opposite wall so that the rafter legs are subsequently the same.

More information on how to attach the rafters to the Mauerlat can be seen in the video below:

The video clearly shows how the fastening of the legs - beams to the beam from professionals should look like.

Installation of rafter legs

For the exact location of the rafter legs, a pencil mark and a meter are made on the Mauerlat. But before that, you need to draw up a diagram or calculation of their location.

The preparation of the rafter legs begins with a cut from the bottom side to 1/3 in width, a cut is made. Their leg will rest on the Mauerlat. From what material the rafters will be depends on the option of their fastening.

The slope of the future roof will depend on the angle at which the beams are fixed. You need to make it not very gentle and steep. It is better to make a calculation before this according to the indicators of the region. If the wind loads are large in the territory of residence, then the angle cannot be more than 20 ° С. At high precipitation rates, the slope is made at 35-40 ° C. So snow and precipitation will not accumulate, and the roof will self-clean.

In the upper part, the rafter legs are connected to the ridge with iron brackets into a single structure.

A bunch of rafter legs at a hanging structure

Beams - legs are assembled together even before their installation. The connecting elements can be bolts or nuts with iron plates. After completing the collection of triangular mounts with rafter legs, they begin to install from the two extreme ones. Then two subsequent ones are installed. It is necessary to fix the frame with temporary jibs. They are removed at the end of installation.

After the legs are completely mounted, fillies are attached to them. The size of the overhang of the future roof will depend on their length. For a wooden house, this distance is taken as maximum to prevent water from entering the walls.

Installation of rafters in a layered structure

With this installation, the rafters begin to be mounted from the bed, on which two supports are installed. A ridge beam is mounted on top of the supports. Additional rigidity of the structure is given by the jibs.

Rafter legs are attached to the ridge beam. If at the same time take the length of the rafter legs a little more and file them with a circular saw after twisting, then the work will be more productive.

Lathing installation

After the installation of the rafter legs is completed, they begin to fasten the crate. At the same time, markings begin from the ridge, where two massive wide boards are first mounted.

It is necessary to mount the crate along the entire length of the gable roof with a step under a certain roof.

When the rafter system is fully assembled, the overhang and gables of the roof are sewn up. After that, the roofing material is laid and the structure is insulated. We talked about how to properly insulate the roof HERE.

As can be seen from the article, it is not difficult to do the work with your own hands, but imagining what the construction of a gable roof looks like, you can easily make a plan and calculation for your log house. And the material that will be used during installation, it is desirable to choose the best and highest quality.

The simplest gable roof in execution is at the same time the most reliable. The availability of do-it-yourself execution does not give rise to self-confidence - before starting work, you need to thoroughly familiarize yourself with the design features in order to competently make decisions and execute them.

Scheme and features of the gable roof device

A gable roof is a roof formed by the intersection of two rectangular slopes at a certain angle. Such a device is the most reliable and simple, so even a person with average carpentry skills can mount a gable roof on their own.

The base of the roof is a truss system that acts as a support for the roofing cake and topcoat. The service life of the roof and the comfort of living in the house depend on its strength and reliability. The truss system, subjected to regular wind and snow loads, must be securely fastened to the building body. This problem is solved with the help of a Mauerlat, which is firmly fixed to the upper plane of the walls of the house. Thus, an almost monolithic system is created that reliably protects the interior of the house from any manifestations of the external environment.

Photo gallery: how you can use the space under a gable roof

Under the gable roof, you can arrange a residential attic A gable roof with a Danish half-hip ennobles the exterior of the building and allows you to increase the size of the attic The attic above the garage can be used to store spare parts, arrange a rest room, or equip a warehouse for household equipment. The area of ​​​​the attic under a gable roof depends on the height of the ridge and the angle of inclination of the slopes

The design of the gable roof truss system

A roof with two opposite slopes is the most common construction used in individual housing construction. The line of intersection forms a ridge, and the side openings of the extreme rafter legs serve for the construction of gables - vertically located walls that create a closed under-roof space. To obtain a strong and durable structure, many retaining and reinforcing elements are used, giving additional rigidity to the entire structure. The gable structure is based on a triangle - the most rigid geometric figure. The rafter system consists of the following main elements:

1. Mauerlat is a wooden beam that acts as a connecting element between the box of the house and its truss system. It is attached to the walls with threaded studs, anchor screws or wire bundles. The size of the cross section of the beam is from 100x100 to 150x150 mm and depends on the size of the building, its number of storeys and the shape of the roof.
2. Rafter leg - a wooden beam measuring 50x150 or 100x150 mm, connected at the top of the roof with a ridge and resting on the Mauerlat with the opposite end. Rafters are the main load-bearing element of the roofing system, which perceives all types of external loads: wind, snow, rain and the own weight of the structure.

   Rafter trusses form the power frame of the roof and determine its geometric shape.

3. Lying - a bar made of wood, laid horizontally with support on an internal load-bearing wall. The size of the bed, as a rule, is equal to the size of the Mauerlat. Supports roof racks.
4. Tightening - an element used in hanging truss systems. Its purpose is to compensate for the tensile forces that occur at the lower ends of the rafter legs.
5. Racks - square bars that transfer part of the load from the rafters to the beds.
6. Struts - structural elements that transfer part of the load from the rafter legs to the puff. Thus, a truss is formed with increased strength characteristics.
7. Counter-lattice - wooden bars ranging in size from 25x50 to 50x50 mm, stuffed onto the upper edge of the rafters. The purpose of the counter-lattice is the formation of a ventilation gap between the crate and the waterproofing film. This element is required when installing a roofing pie in the attic.
8. Lathing - a supporting base for installing the finishing coating of the roof. The lathing is solid or sparse and can be made of 25 mm thick boards, waterproof plywood, OSB sheets and other similar materials. The choice of the design of the crate depends on the characteristics of the finish coating.
9. Skate - a horizontal beam along which opposite slopes intersect.
10. Roof overhang - is a continuation of the rafters at a distance of up to 40 cm from the walls of the building. It protects the walls from getting wet, and also serves to accommodate spotlights, which are an integral part of the ventilation system of the under-roof space. With insufficient length of the rafters, the overhang is formed by additional details for their lengthening - filly.

    The truss system of a gable roof consists of triangular trusses, based on a Mauerlat and a ridge, battens and several auxiliary elements that reinforce the structure.

Calculation of the load on the rafter system of a gable roof

The rafter system experiences certain loads, which can be divided into two types.

1. Permanent loads acting independently of any other factors. Their value is determined by the design of the roofing pie and consists of the weight of waterproofing and vapor barrier films, insulation, additional elements, fasteners and any other elements of the roofing, including the finish. In practice, the average weight of all components of the roof of a house is about 40–45 kg / m 2. More precisely, this value can be calculated by summing the values ​​​​of the specific load of each material used, which can be taken from the lookup tables. When calculating the weight of the roof, it is recommended to lay a safety margin of 10%.

   When calculating the load, the weight of each element of the roofing pie is taken into account

2. Variable loads. These include the effects of wind and snow, depending on their intensity. In fact, the roof of the house is a sail that takes the load from the wind. The force of direct impact on the roof along the normal depends on the angle of inclination of the slope - the smaller it is, the lower the load. At the same time, turbulences appear on the lee slope, and a load appears on the roof with a reverse impact vector. With hurricane winds, the pull-off force can reach 630 kg/m 2 . Variable loads include snow impacts. It should be noted that they also have clearly defined regional indicators.

   Wind loads are a risk factor for roofs as they create large tearing and overturning forces.

Obviously, a careful calculation of the loads from snow and wind, taking into account local climatic conditions, is vital when choosing a roof structure and materials. These loads can be determined from a map compiled on the basis of SNiP 2.01.07–85.

On the map, you can determine the magnitude of the wind and snow load in the construction region

The values ​​of snow and wind load marked on the maps for each region are called standard. In order to obtain the calculated snow load, the standard value must be multiplied by a special coefficient that takes into account the angle of the roof. This ratio is equal to:

• 1 with a slope of less than 25 o ;
• 0.7 at an angle of inclination from 25 to 60 o ;
• 0 for steeper slopes.

The calculated wind load is determined by multiplying the standard value by a factor that takes into account the height of the building and the type of terrain in which construction is underway.

Table: correction factor for calculating wind load (taking into account the height of the building and the type of terrain)

The specific load of the most popular roofing materials can be taken from the following table.

Table: weights of some roof materials

It is possible to take into account the peculiarities of the impact of different types of loads only in the aggregate, therefore, calculations of this nature should be entrusted to an experienced specialist.

Video: calculation of the truss system

Types of gable roof truss systems

According to the principle of the device, truss systems are of two types:

1. Hanging.
2. Layered.

Hanging rafters are used for buildings in which the load-bearing supports are located at a distance of up to 10 meters in the absence of an intermediate wall inside the building box. For other cases, it is necessary to use a layered truss system.

Features of the hanging truss system

The support for the hanging rafters are the outer walls. Since the arch has a connection at the top point, when vertical loads are applied to it, bursting loads are created on the lower supports. To compensate for them, puffs are used - horizontal ligaments between the lower ends of the rafter leg. The result is a rigid power triangle. When constructing an attic room, floor beams are used as puffs. Various design solutions for a hanging truss system are possible:

1. A simple three-hinged arch. It is a triangular structure. In this case, the tightening works only in tension and is not a support. Therefore, it can be replaced with a conventional metal beam. The connection of the cornice assembly in this case is performed by a simple orthogonal tie-in using wooden overlays or metal plates.

   The three-hinged arch is the simplest truss truss design for a gable roof.

2. Three-hinged arch with reinforcement. This scheme was previously used in the construction of industrial buildings, when the span exceeded 6 meters. At the same time, the puff is suspended on a headstock made of wood. The knots are connected using metal parts and are equipped with devices for tension adjustment. The main load in such a system falls on the ridge of the roof. In individual housing construction, such truss systems are not used.

   A three-hinged arch with reinforcement differs from a simple one by the presence of a vertical stiffener (headstock) and the ability to adjust the tension at the joints

3. Hinged arch with raised puff. In this version, the rafter leg is partially unloaded through the roof ridge with a suspension to a raised puff. It rises to a height of at least 2.2 m from the level of the attic floor. Such a system is ideal for arranging an attic room in the under-roof space. The connection of the puff with the rafters is made by a tie-in, as a result of which the connection in the node becomes fixed.

   Hinged arch with raised drawstring ideal for attic roofing

4. A three-hinged arch with a crossbar is used to strengthen the truss system by creating an additional power triangle. The system is used with significant bursting loads. The connection of the crossbar with the rafter must be fixed, otherwise the entire system will not have the necessary rigidity.

   An additional horizontal element (crossbar) gives the system greater resistance to bursting loads

The crossbar, unlike the lower tightening, works in compression, not in tension.

In addition to those listed, other elements are also used to strengthen the roofing skeleton. Very popular are the struts and racks located in the system at the places of the greatest loads on the rafters.

In the most loaded places, roof trusses can be reinforced with struts and struts.

Video: rafter system step by step

Rafter systems of layered type

Laminated rafters are used for buildings with a width of more than 10 meters. They are characterized by the presence of a load-bearing wall inside the building, which is an additional support for the truss system. Layered structures are of several types:

In non-thrust layered systems, the main load from the roof frame is transferred to the Mauerlat

Determining the pitch of the rafters of a gable roof

The task of ensuring sufficient strength of the truss system is solved by selecting the material for the manufacture of its elements and calculating the parameters of their installation. The pitch of the rafters is one of these elements and is selected depending on the weight of the roofing cake. The distance between the support beams is usually set within 0.6–1.5 m. The actual step between the rafters depends on the geometry of the roof and is calculated as follows:

1. The number of rafter legs is determined. To do this, you need to use the ratio n \u003d L / d 1 + 1, where n is the number of rafter legs, L is the length of the roof along the ridge, d 1 is the desired distance between the rafters.
2. The estimated distance between the rafters is calculated, for which the length of the roof along the ridge is divided by the amount obtained in the previous paragraph: d = L / n.

For example, consider a variant with a roof length of 13 m with a preferred distance between rafters of 750 mm (option for a roof with ceramic tiles).

1. The number of rafter legs n \u003d 13000 / 750 +1 \u003d 18.33. Since the number of rafters must be an integer, we round this value up to 19.
2. Rafter pitch d = 13000: 19 = 684 (mm).

Thus, on the roof of our choice, the rafters must be installed in increments of 68.4 mm.

It should be remembered that the result obtained is the distance between the axes of the rafters.

Knots of the truss system of a gable roof

We have already considered the main types of connections in the nodes of the supporting structure of the roof above. But it makes sense to dwell in more detail on auxiliary materials that make it possible to make the truss system more reliable and durable.

It is possible to strengthen the fastening of parts during the installation of the truss system using metal plates and corners of various shapes

Such products are made of galvanized steel up to 1.5 mm thick. They have a different configuration and can be installed on any type of connection.

Photo gallery: types of connections in the nodes of the gable roof truss system

In the ridge part, the rafter legs are usually connected by bolted flat plates. To strengthen the structure of the truss system, it is necessary to select metal plates that correspond to the configuration of the fastening unit Sliding junctions of nodes unload the truss structure Junction points in the truss system can be further reinforced with metal inserts Depending on the type of truss system used, there are different ways of attaching the ridge assembly. On flat joints operating under heavy loads, it is convenient to use nail plates

All docking nodes of the truss system have the function of strengthening the rafters due to the redistribution of loads and strengthening of the bearing elements. So, in the lower part, the rafters are supported on the Mauerlat at a right angle, for which they perform the corresponding inserts.

To strengthen the rafter system, they try to use connections with maximum bearing capacity, for example, inserting the rafter into the Mauerlat at a right angle

In addition, metal mounting plates are used for additional reinforcement in the docking nodes. The same principle is used when installing struts to the rafters. In any case, the mating parts must work "on the stop" and not move during operation.

Any parts must be loaded along their axis

There are three main types of nodes in the truss system:

1. Skate connections. This is the joining of two rafter legs at a given angle along the line of intersection of the slopes. They can be articulated or deaf. The former are used when constructing a truss system on timber or log houses, which tend to sag and rise depending on the season for almost the entire period of operation. Blind joints are used in the roof systems of houses made of building stone. In such buildings, a reinforced belt is installed on top of the wall, which takes on lateral loads.
2. Fastening the lower ends of the rafter legs to the Mauerlat. Since they are at an angle to the support beam, a sliding vector is created, directed outward from the building. To compensate for it, a tie-in is made in the Mauerlat, and a heel is made on the rafters. The rafter is inserted into the groove with an emphasis on it and fastened with a nail through the edge of the beam into the Mauerlat. Additional supporting parts made of bars are also used. In cases where the rafter beam must move (on wooden log cabins), sliding fasteners are used. They make it possible to compensate for seasonal changes in the height of the walls.
3. Other nodes. All other parts of the truss systems are essentially thrust elements working in compression, rarely in tension. They are installed by cutting into mating parts to prevent them from moving under load. Such details include crossbars, struts, racks, stops and other similar details.

For a stronger connection, the additional elements mentioned above are used.

Installation of a gable truss system

Currently, the construction market offers services for the manufacture of custom-made roof trusses for specific buildings. It should be noted that this service has a number of advantages:

1. Guaranteed product quality, ensured by the use of special equipment and assembly technologies.
2. Fire safety, as all parts of the trusses are flame retardant treated.
3. Extended service life, which is achieved by antibacterial treatment of products with special compounds.
4. Ease of installation of finished farms.

The only drawback of this method of installing the truss system is the relatively high cost of products.

For self-construction of a gable roof, you can use ready-made roof trusses ordered from professional manufacturers

Assembly of roof trusses on the ground

The assembly of rafters on the ground is used in cases where there is a flat area of ​​sufficient size directly next to the house for the manufacture of trusses. At the same time, not complete trusses are mounted, but rigid structures of three or four parts, which can be lifted to the installation site by the efforts of two or three people. The ascent is made with the help of ropes along the sleds. The advantage of this assembly method is the possibility of using a single template, which ensures high manufacturing accuracy of each structural element. A possible option for partial installation of trusses below is as follows:

1. Make a slipway for assembling trusses. It consists of three sites, the distance between which corresponds to the length of the mating parts. They can be assembled from several boards or bars located in the same horizontal plane.

   For the convenience of assembling the truss on the ground, a free area of ​​​​a certain size and auxiliary elements are required on which structural details can be placed.

2. To assemble the first truss, you need to take two rafter legs and a puff - lower or upper.
3. Having laid out the parts on the slipway, place them in accordance with the truss drawing and fasten them with nails. Check the truss blank for compliance with the dimensions specified in the technical documentation. If necessary, correct the location of the components.
4. Perform the final fixation of parts in the truss nodes using additional mounting plates. Nail plates can be installed using a power clamp, using additional thick steel pads under its jaws.

   Power clamp allows you to pre-pull the nail plates, and then fix them in any convenient way

5. Lay the details of the second truss on top of the first and fix with clamps, exactly following the contours of the lower truss, which plays the role of a template. After assembling the second farm, remove it to the side.
6. Make the required number of farms, repeating the operations from the previous paragraph. Thus, full compliance of all manufactured trusses is ensured.

   When manufacturing roof trusses according to one template, they will exactly repeat the size and shape of each other

Installation of the truss system at the installation site is carried out as follows:

1. The first two farms rise to the roof. To do this, you can use an inclined flooring of several bars and fairly strong ropes.
2. Gable trusses are installed first at the ends of the roof. They need to be set strictly vertically and fixed to the Mauerlat with temporary jibs.

   First you need to install gable trusses

3. Between the gable trusses, a construction cord is stretched perpendicular to the location of the rafter legs.
4. Each subsequent truss is installed in compliance with the previously calculated rafter pitch.

   In order for all truss trusses to be installed evenly, twine is stretched between the extreme structures

5. After the installation of the last truss, the entire structure of the truss system is reinforced with girders, after which the temporary fasteners are dismantled.
6. Next, the rest of the structural elements are mounted - jibs, ridge beams, beds, racks, etc., provided for in the design of the truss system.

Additional strength to the roof is given by the crate, stuffed last.

Assembly of rafter legs directly at the installation site

Local assembly of rafters is used on small roofs. At the same time, blanks are fed up, from which the necessary details are cut. Installation is carried out from the bottom up, starting with the installation of the rafter legs. The horizontal level of the truss system is controlled by tensioned cords, and the verticality of the truss assembly is controlled by a plumb line. The installation order is the same: gable trusses are mounted first, then the rest in any convenient order.

The assembly of the rafter system directly on the roof begins with the installation of racks and a ridge run, on which the rafters are laid

Accurately fulfilling the requirements of the drawings, you can mount the truss system yourself. It is almost impossible to do this alone, so the participation of one or two assistants is mandatory.

Video: do-it-yourself installation of rafters

When assembling a truss frame for a gable roof, it is important to follow certain rules:

1. All wood used for the installation of the truss system must be treated with antiseptic and fire-fighting compounds.
2. When working with hand-held power tools, the safety requirements specified in the instructions must be observed.
3. Installation of nail plates cannot be done by hammering, this leads to their deformation. A clamping tool must be used during installation.
4. A layer of waterproofing must be laid under the Mauerlat. Traditionally, ruberoid is used for this.
5. When installing the truss system, you need to use fasteners with a protective coating.
6. Installation of the truss system should be carried out in dry calm weather.

Video: gable roof for metal tiles

Like any roofing system, a gable roof requires careful and responsible attitude. Mistakes in the construction of such roofs are usually expensive. Not only the careful selection of materials is important, but also their competent use. However, most of the work can be done independently. I wish you success!

A gable roof is a simple but effective roof that reliably protects a building from wind and precipitation. Installation of the gable roof truss system can be done independently, but first you should familiarize yourself in detail with the design and the basic rules for its construction.

The truss system consists of several parts, each of which plays an important role.

In addition, the gable roof truss system may have additional elements necessary to strengthen the structure:

• struts - bars located at an angle between the rafters and the puff;
• headstock - beams installed vertically in the center of the truss system (required for roofs whose width is within 6.0 - 7.5 m);
• crossbar - a beam installed parallel to the tightening, pulling together the rafter legs (used for roofs up to 6 m wide).

About the types of truss systems

The device of the gable roof truss system is carried out in two ways.

1. Hanging rafters rest on top of each other, the bottom - on the Mauerlat. To increase reliability in the lower part, the rafter legs are connected by a crossbar. This system is suitable for use in roofing buildings up to 10m wide. This is the only possible solution for projects that do not include a load-bearing wall in the central part of the structure.
2. Laminated rafters, in addition to the Mauerlat and the ridge beam, also have an additional point of support - bars vertically mounted on the middle load-bearing wall, called girders. The frequency of installation of runs coincides with the step between the rafters.

Calculation of the truss system of a gable roof

• The height of the ridge depends on the distance between the load-bearing walls on which the rafter legs rest, as well as on the planned slope of the roof. The latter is chosen based on local conditions: for snowy areas, the angle of the roof slope should be large, and for windy areas - smaller. An angle between 35-45 degrees is considered optimal.
• The height of the ridge is determined by multiplying half the distance between the rafter legs by the tangent of the slope angle (table value).
• The distance between the rafter legs and the length of the rafters affect the choice of the beam section (see table).

• The length of the rafter is calculated by dividing the ridge height value by the sine of the slope angle.

The formula below is used in the calculations.

So, the actions in calculating the roof come down to three points:

• we calculate the length of the slopes (the distance from the bottom point of the ridge and the edge of the overhang);
• make adjustments for additional elements: parapets, skylights, firewall walls;
• we select roofing material and calculate its quantity.

Note: the amount of roofing material and the time required for its installation depend on the height of the ridge.

How to make a gable roof truss system

Before proceeding with the installation of the truss system, it is necessary to check the level of the load-bearing walls: the horizontal discrepancy should not exceed 5 mm. All corners must be straight (unless otherwise provided by the project). In the places where the Mauerlat is attached, studs made of steel rods with a diameter of 10-14 mm are installed in advance with a step of 1-1.5 m. The lower ends of the studs are laid with bricks in three rows.

Do-it-yourself gable roof truss system: installing a Mauerlat

The installation of a gable roof truss system begins with the laying and fastening of the Mauerlat. Here is a step by step installation guide for you.

1. In the place where the Mauerlat is laid, 2-3 rows of roofing material are laid - for waterproofing.
2. The distances between the studs are measured, all dimensions are transferred to the Mauerlat bars.
3. Holes are drilled in the wood in the marked places.
4. A beam with a section of 100 × 100, 150 × 150 or 200 × 200 mm is laid over the load-bearing walls on studs, which should protrude by 30-40 mm. There should be some distance between the Mauerlat and the outer side of the walls. This gap can be bricked up.
5. Mauerlat bars are attached to the studs using large-diameter washers and nuts. Welding nuts are allowed.

Note: in the case when fastening with studs is not possible, use the binding of the Mauerlat with wire or wooden brackets. A long wire with a diameter of 3-4 mm is immured into the wall 3 rows before the end of the masonry. Staples made of wood are used in wooden houses.

Installing rafters: basic rules

At this stage, it is important to observe the accuracy of the location of the parts and ensure their reliable fastening. For this are used:

• steel corners;
• studs with washers and nuts;
• brackets;
• metal plates.

The truss system of a gable roof assumes compliance with the following rules during the preparatory work.

1. For rafters, well-dried, seasoned wood is selected. The moisture content of the material should not exceed 2.5%, otherwise the boards and beams may be deformed.
2. Wood of the 3rd grade is suitable for struts and racks, but it is necessary to minimize the number of knots.
3. All parts made of wood should be treated with flame retardants and antiseptics.

Sequence of actions during installation.

Some nuances of mounting the crate

The details of the crate are fastened with self-tapping screws perpendicular to the rafters. According to the density, the following types of crates are distinguished:

• solid: OSB boards or moisture-resistant plywood are laid on top of the rafters with a small compensation gap at the joints (used for roll and other flexible roofing materials);
• sparse: the distance between the bars is 450 mm or more (for example, for slate);
• standard: between the elements of the crate should be 200-400 mm (for tiles and metal tiles).

Important: the crate is attached to all rafter legs. Wood is selected without knots and grooves. "Cyanosis", the presence of rot and damage by pests are not allowed.

Rafter system of a gable roof. Pediment: ways of tying

The decoration of the pediment can be made in various materials. Your attention is the truss system of a gable roof (photo and description of some techniques for decorating a pediment).

Rafter system of a broken gable roof

In order to increase the roof space, to make it residential, they construct a gable sloping roof. Such a design can be represented in the form of three triangles, one of which is located above the attic ceiling, and the other two are on the sides.

The technology for creating a broken gable roof provides for a certain sequence of actions.

1. In the ceiling beams, tie-ins are prepared for mounting the racks. In the case of a floor device using concrete slabs, beds are laid on them.
2. Install vertical racks and attach struts. The structure without struts can be assembled.
3. Lay side runs.
4. Alternately, the legs of the layered rafters are mounted. If necessary, contractions are additionally fixed.
5. Hanging type trusses are made on the ground, all the parts are connected and then lifted to be installed in their place.
6. In the case of the use of layered rafters, the side runs are connected by beams that serve as details of the ceiling of the under-roof space. In the beams, tie-ins are made for fastening the racks of the ridge beam.
7. Install the ridge bar.
8. Attach layered rafter legs.
9. Mount the crate, the type of which is selected depending on the roofing material.

At the end of the article on how a gable roof truss system is created, a video with expert comments.

The roof of a building is an important and responsible structural element that performs several functions at the same time. The main task is to protect walls and ceilings from the ingress of rain or melt water, which destroys the materials of the walls and the entire structure as a whole. Additional functions are the conservation of thermal energy, ensuring the operation of various life support systems at home, protection from wind, dust and other atmospheric and climatic manifestations. The roof structure is complex, the roof covering, which takes on all the main tasks of sealing and cutting off from low temperatures, needs a reliable and durable carrier system.

Gable roof and its features

The roof is one or more planes covered with a roof and designed to cut off external weather or atmospheric manifestations. Each plane is called a pitch, so a gable roof, by definition, has two protective planes. They can be symmetrical or asymmetrical, have the same or different angles. The configuration is determined by the architect's intention, the climate in the region, the presence of strong winds, etc. The most common are symmetrical gable structures, as they create a uniform load on the walls and foundation.

Slope angle

Roof planes must necessarily have a slope that ensures the flow of snow or water. The angle value is a design indicator, it cannot be chosen arbitrarily. Factors affecting the choice of slope:

1. The amount of snow falling in winter, typical for a given region.
2. The number of rains, their strength and duration.
3. Prevailing winds, their strength and duration, the possibility of squally gusts or hurricane values.

The meaning of calculating the angle of inclination of the slopes is to determine the optimal position of the planes, which ensures the timely melting of snow, the runoff of rainwater and, at the same time, does not create excessive resistance to wind currents. Loads from snow in winter amount to tons, and gusts of wind create a significant impact on the supporting structures of the house and the foundation. We have to look for a "golden mean" that allows you to get a sufficient slope with low wind resistance. In some regions with certain prevailing winds and high rainfall, an asymmetric roof shape, sloping on the windward side and steep on the leeward slope, becomes the best choice. To achieve such a shape, it is necessary to create two planes of different areas with a fracture line located outside the axis of symmetry of the building. When creating a house project, it is imperative to take into account the prevailing direction of the winds so that the load falls on the slopes of the roof and creates a minimum stress on the supporting structures.

What is a truss system

Gable roofs usually have vertical continuations of the walls from the end part - gables. Small buildings may not have a truss system at all, when the roof is laid on longitudinal planks laid on the slopes of opposite gables. For larger buildings, it is necessary to have a strong support. This is how the assembly of the gable roof truss system looks like with your own hands:

Roofing is able to ensure the tightness of the outer protective layer, not letting in moisture or wind. At the same time, the roof has no bearing capacity, it needs a well-organized support system. As such, rafters perform several tasks:

• create a reference plane for the roof, form a frame;
• form the configuration of the roof, create the required number of planes - slopes;
• provide the necessary rigidity and strength;
• connect the roof to the supporting structures of the building.

The functions performed put forward a lot of requirements for the system, the main of which are strength and the ability to maintain shape despite a long service life and tolerated loads. Here is an example of the simplest way to calculate the strength of each individual rafter:

Externally, the gable roof rafters look like two rows of sloping slats, connecting at the top. To ensure the strength and rigidity of the structure, there are various elements that need to be considered in more detail.

Elements of the truss system

Rafter construction is one of the most complex of all building systems. It consists of:

1. Mauerlat. A strapping belt made of timber 100 × 150 or 150 × 150 mm, laid along the perimeter of the walls in the upper end part. It serves as the basis for the rafters, connects the roof to the walls.
2. Sill. It is laid along the longitudinal axis of the building, provides support for vertical support elements. It is used only on buildings with an internal middle load-bearing wall.
3. Sprengel. Reinforces Mauerlat corner joints. It is a kind of strut laid horizontally and providing a diagonal ligament.
4. Puff. Connects the opposite bars of the Mauerlat, compensating for the bursting load from the inclined elements.
5. Rack (grandmother). A vertical piece that supports a skate.
6. Skate (run). A horizontal bar (or board) that forms the upper edge of the roof, connecting inclined planes - slopes.
7. Rafters (rafter legs). Inclined planks forming the planes of the slopes. With their lower ends they rest on the Mauerlat beam, with their upper ends on the run.
8. Struts. Inclined elements that serve as additional supports for the rafters at the points of greatest load. Installed perpendicular (or at a slight angle) to the rafters.

Important! The above list is not exhaustive, there are still many different elements of truss systems, but they are usually not used on gable roofs.

What are rafters made of

The material for the manufacture of rafters is traditionally wood - timber and edged boards. The advantages of wooden parts of the truss system:

1. Relatively light weight, eliminating high loads on the supporting structures of the house.
2. Availability, prevalence of material.
3. Wood is easily processed, cut, combined.
4. High maintainability of the material. Any element can be replaced or put in order during operation.
5. Durability, reliability of a design.

There are also disadvantages:

1. Wood is susceptible to decay, mold or fungus.
2. High susceptibility to water, the ability to absorb and release moisture.
3. Swelling, wood changes linear dimensions.
4. Wood is flammable.
5. Installation of rafters requires the use of material with high requirements for moisture and quality.

Recently, an alternative type of rafters has appeared - metal. They are devoid of most of the shortcomings of wooden parts, are not afraid of water, are strong and durable. The disadvantages include only the possibility of corrosion (although the metal has a protective coating), relatively high weight and increased complexity of the connection compared to wood. In addition, metal rafters are much more expensive, which limits their use in private housing construction. The main consumers of such parts are the builders of large facilities that need a strong roof of large dimensions. The loads experienced by the truss system in such conditions are very high and require the use of reinforced parts.

The process of installing a metal truss system is nothing more difficult than the process of assembling a wooden structure. You can verify this for yourself:

There are combined truss systems that use both metal and wooden elements. This option allows you to slightly reduce the weight of the structure, it is more economical and easier to install. The only crucial point is the need for waterproofing the joints of metal and wooden parts, since the condensate that forms on the metal can get on the wood, cause rotting and failure.

Types of truss systems

There are two options for the design of truss systems:

• with hanging rafters;
• layered truss system.

The fundamental difference between these options is the fulcrum of the rafter legs. The first option involves attaching the base of the rafters to the Mauerlat and connecting them at the top point when the run (ridge) rests on them. The second option provides a more durable run with load-bearing functions, and the rafters are fully fixed to the Mauerlat and to the ridge beam.

Both options are actively used. In practice, they differ little from each other, since the features of the implementation of one type or another directly depend on the size of the building and the design of the load-bearing walls. The construction of medium-sized houses forces the use of structures that are more similar to the layered type, which provides greater strength and rigidity of the system. Let's consider both options in more detail:

Hanging rafter system

The traditional option for using hanging rafters is small houses, with a maximum distance between supports of up to 6 m. This is due to the appearance of an additional load - in addition to the weight of the roof and exposure to atmospheric factors, the rafters receive self-supporting properties. With an increase in the size of the house, the load becomes excessive and requires reinforcement of the structure.

A feature of hanging truss systems is the bursting force applied to the Mauerlat. To compensate for this pressure and protect the walls from deformation and subsequent destruction, puffs located at the bottom of the rafter legs are necessarily used. During construction, they often resort to the manufacture of so-called. truss trusses having the shape of an isosceles triangle. They are made on the ground or assembled directly on the top of the house and installed on the roof Mauerlat as a finished structure. This method somewhat speeds up the process of creating a roof, since elements of the same type are used, which allows you to repeat the same operations several times and get the right number of elements.

Layered truss system

The construction of houses of medium and large sizes requires the creation of a strong and rigid truss system. The weight of the roof, snow and wind loads force the use of a layered type of system. It differs, first of all, in the installation technique. First, supporting elements are installed - Mauerlat, bed, racks and run. They have a high bearing capacity and are designed to take significant loads, so they are made of timber. Rafter legs are installed based on the Mauerlat from below and on the run in the upper part, with a large length they are reinforced with struts.

Experts note the great reliability of the layered truss system. When assembling, there are no ready-made parts of the structure, so all work is carried out directly on top of the building. There is no need to lift heavy finished elements, only material is fed up. Each bar is installed separately, which ensures the accuracy and tightness of the connection, avoiding poor-quality installation or errors. In comparison with structures with hanging rafters, layered truss systems significantly benefit in strength and allow you to get a better and more durable supporting structure. In regions with high rainfall, snowy winters, strong gusty winds, a layered truss system for a gable roof is much preferable and more reliable.

How to choose the optimal design of gable roof rafters

The main selection criterion is the size and purpose of the building. Small houses that do not have a large area of ​​​​roofing can do with lighter support structures. Medium-sized buildings, large buildings must have a strong and powerful truss system that can withstand the pressure of snow, wind, and withstand the weight of the roof. In order to decide how to make a roof correctly, it is necessary to find out the climatic features in the region, the amount of precipitation, the possibility and frequency of strong winds, heavy snowfalls, etc. These data are included in the calculation, they are available in the tables of SNiP or in reference literature.

At the same time, one should not be too zealous and build an overly powerful truss system for a small house. It must be remembered that power is an additional material, and therefore an increase in the weight of the structure. The optimal choice will allow you to get a fairly strong and lightweight system that does not overload the foundation and walls, but fully provides protection from external atmospheric manifestations.

Installation of a gable roof truss system

Consider how to properly install the rafters with your own hands on a gable roof. The task is difficult, but quite solvable. The main condition will be the possession of the necessary knowledge and accuracy, thoroughness in performing all the necessary operations. A simpler option is a system with hanging rafters, but it is more correct to consider complex structures, since layered rafters on a gable roof are more reliable, and the work technique is almost the same.

Preparatory operations

First of all, you need to make a careful calculation of the system. For an unprepared person, such a task will certainly be overwhelming, but the solution may be to use an online calculator, of which there are many on the Internet. It is easy to use them - you need to substitute your own data (roof dimensions, other values) into the windows of the program and get ready-made parameters for the truss system. For more accurate values, you can repeat the calculation on another calculator.

The second step will be the acquisition of material. Consider a more complex case - making a wooden truss system with your own hands. For it, you will need a wooden beam measuring 100 × 150 or 150 × 150 mm, as well as an edged board 50 mm thick. On the quality of the material should pay close attention. Wood should not have defects:

• rotten areas;
• traces of insect activity;
• cracks;
• the number of knots should be limited, you should not choose material with dead (dropped out) knots;
• wood moisture should be in the range of 18-22%.

The selected and purchased material must be folded in the area under a canopy. It is impossible to tightly lay boards or timber on top of each other, it is necessary to use gaskets for free air movement. An example of proper storage of lumber:

Important! Of great importance is the presence of resin in wood. If a tapping (resin collection) was performed on the site, then the material becomes lighter and dries faster. At the same time, the risk of damage by a fungus, rotting or absorption of atmospheric moisture increases.

In any case, the purchased material must be kept for some time (at least a couple of weeks) on the site in order to gain atmospheric humidity characteristic of this region. If you start construction immediately, there is a risk of distortion of the structure, the occurrence of unnecessary stresses.

The next and final step of the preparatory operations must necessarily be the bactericidal treatment of purchased wooden materials:

Important! If you want the roof to serve you for at least 50 years without a single repair, you need to treat the wood with an antiseptic. This simple operation will avoid damage to the lumber by bark beetles, and will also prevent the material from rotting.

Do-it-yourself installation of gable roof rafters

Consider how a do-it-yourself gable roof truss system is made. The work is carried out in stages, in strict order. Since the installation of a structure with hanging rafters is somewhat simpler, consider a more labor-intensive option - installing a layered timber truss system for a gable roof.

The first step in installing rafters for a gable roof with your own hands is to prepare the walls of the building without a Mauerlat. An example is shown in the photo:

The mounting surface of the walls is leveled with a small layer of mortar. After the solution is completely dry, bituminous waterproofing is applied on top of it, or one layer (strip) of roofing material is laid. Next, a board is laid on top of the "sandwich".

The second step is the installation of the Mauerlat. How to do this is shown in detail in the photo below:

The beam piping is installed on a waterproofed base formed by the inner part of the end of the walls. A brick or block ledge is usually installed along the outer edge, providing protection against water ingress from outside. Sometimes Mauerlat is made from edged boards, which is justified given the small size of the building and roof. For insulation, a double layer of roofing material is used, with an intermediate application of heated bitumen. The connection of the beam both in the longitudinal and in the transverse direction is made in half a tree. Studs are used to strengthen the strapping. Before finally putting the beam in place, holes are made at the end of the walls for deepening the ends of the studs or dowels, installing anchor bolts.

Then the bed is installed. Installation is carried out in a similar way, on a waterproofed base. The connection with the Mauerlat is made in half a tree, reinforced with metal staples or nails.

Racks are installed. They are mounted on a bed, additionally reinforced with struts or struts. A run is attached to the top of the racks.

Installation of rafter legs begins. They are attached to the Mauerlat and run with nails. To illustrate, here are a few examples:

There are also metal fasteners for gable roof rafters, which provide high-quality connection of parts. It must be remembered that between wood and metal there must be a gasket made of roofing material or glassine. The installation step of the rafter legs is determined by calculations made in advance. The durability and reliability of the roof depends on the accuracy of observing the dimensions. Here is an example of assembling truss trusses on nail plates:

At the end of the installation of the gable roof truss system, the crate is installed.

There are two types - the crate itself and the counter-crate. The first type is used in the absence of insulation, and if it is planned to be installed, then both layers are mounted. In such cases, the counter-lattice provides the necessary ventilation gap between the roof and the insulation and at the same time serves as a support for the roofing material. The crate performs the function of supporting the insulation and provides the necessary clearance between the rafters and the counter-crate.

In parallel with the crate, a roof overhang is made. It provides protection of the ends of the walls from water. It is impossible to form an overhang immediately during the installation of the rafter legs, therefore, work is carried out at the final stage. To form an overhang, an edged inch board is used, from which a continuation of the rafter line is made, taking into account the thickness of the crate, extending beyond the perimeter of the walls by the required amount.

Do-it-yourself installation of gable roof rafters allows you to significantly save money, complete all the work at a convenient time for yourself and gain valuable experience in performing such work. The main condition for obtaining a high-quality result will be accuracy, thoroughness in the implementation of all actions, preliminary familiarization with the rules and features of the installation of a particular element.

Video instructions

The gable roof truss system is considered one of the simplest in purely constructive terms. It consists of only a few elements, the number of which decreases or increases due to the size of the roof itself. But with apparent simplicity, the process of erecting a gable roof itself requires knowledge of some of the nuances that affect the quality of the final result.

Rafter system for a gable roof

What is a gable roof

From the name it becomes clear that the roof structure is two slopes that have a rectangular shape in the plane. More often, the slopes have the same dimensions, but there are so-called asymmetric designs in which the slopes differ in size from each other.

In this case, the slopes are set to each other at a certain angle, which is called the slope. The line of contact is the ridge beam, which is part of the truss system. In a simple way, it is called a ridge, and it is the highest point of the roof.

The side planes formed by the slopes are called gables. They are triangular in shape. After the construction of the roof, the sidewalls are lined with sheet or panel materials: plywood, OSB, even boards, etc.

What is a gable roof truss system

The basis of the structures of the slopes are rafter legs, they are also rafters. They are made either from lumber (beams, boards), or from a steel profile (corner, channel). In private housing construction, wood is used. It is easier to work with, plus lumber is cheaper.

The device of the gable roof truss system is not only rafters. In addition to them, there are several other mandatory elements. The photo below shows all the elements of a gable roof. Let's designate them.

Each of the elements of the roof has its own purpose.

Elements of the gable roof truss system

Mauerlat. In fact, this is a beam on which the rafters rest. Its purpose is to evenly distribute the load from the rafters on the walls of the house. If the Mauerlat is not used, then the rafters will put pressure on the walls pointwise, that is, large stresses will arise at the installation sites, which will lead to cracking of the walls.

rafters installed at an angle.

Skate, he is a ridge beam or run. Its task is to form a place for joining the rafter legs. A ridge beam is an optional element of a gable roof. There are designs in which it is not installed. But more on that below.

Puffs. They are not always used, but only on hanging rafters or if the rafter system is installed on a wide house.

floor beams that form the ceiling in the room and the floor in the attic.

One of the floor beams, which is called lying down. It additionally functions as a base for the support posts that support the rafters. Not always used.

Support legs, they are grandmas supporting the rafter legs. They are installed only if the span of the house is at least 6 m.

Struts, they are also diagonal props. They are used only if the support posts cannot ensure the overall reliability of the truss system.

There is another element that is clearly visible in the photo below. These are support posts for the ridge run. They are installed if the design of the truss system is heavy. That is, the entire structure is assembled under heavy roofing material, for example, under ceramic tiles.

Sloped rafters with support posts under the ridge run

You might be interested! A warm roof is an important detail in the construction of an energy-efficient home. From the article at the following link you can find out.

Types of rafters

The roof truss system (gable) can be assembled from layered or hanging rafters.

Layered

They got their name because the lower ends rest on the walls of the house, the upper ends on the ridge run. In this case, the truss elements are subjected to loads that bend them. The design is reliable, durable, with a large bearing capacity.

The photo above just shows the rafter system of a layered view. It is clearly seen that the legs rest in the upper part on the skate. In this case, there are two types of fastening of the rafters themselves in the upper part:

fastening is made to the ridge:

fastening is made between each other with an emphasis on the ridge (photo above).

hanging

It is necessary to immediately indicate that this type of truss system can be used if the distance between the walls of the house does not exceed 12 m. Because the rafters abut the lower ends against the walls, and the upper ends only between themselves (there is no ridge run in the structure). Hence the low bearing capacity with a large expansion.

Hanging rafters for the roof have one purely design flaw - a large support load on the walls of the house. To reduce it, puffs are installed between the legs to form a rigid triangle. Often, the functions of the puffs are performed by the load-bearing floor beams.

If necessary, strengthen the hanging rafters, install racks and struts under them.

Hanging gable roof rafters

Installation of a gable roof truss system

Two types of truss system determine two types of their assembly technology. Let's consider each separately.

Installation of layered rafters

There is a certain sequence for assembling layered rafters.

Two extreme support posts are installed under the ridge beam. They will not only support the beam, but also be the elements that form the gables of the building. Attach them at the bottom to the Mauerlat. At the same time, they are strictly set vertically, and the upper ends are in the same horizontal plane. To do this, a strong thread is pulled between the racks, the level is checked for horizontalness. If there are deviations, then one of the supports (low) is raised using wooden supports.

Intermediate support posts are mounted along a horizontally stretched thread in increments of 2-2.5 m. To prevent the beams of the racks from moving, they are supported with temporary fasteners: props or puffs.

A ridge beam is laid on the racks, which is attached to them.

Produced in pairs installation of gable roof rafters. Installation can be started from either side. Fastening is immediately carried out to the Mauerlat and to the ridge. The main thing is to maintain the distance between the legs, which is determined depending on the severity and bearing capacity of the roofing material. Usually this parameter is indicated in the project of the house.

If necessary, intermediate support posts and struts are mounted.

Installing rafters on a ridge along a stretched thread

Installation of hanging rafters

The technology for installing hanging rafters is different. To do this, the entire structure, assembled from two rafters and puffs, is assembled on the ground. That is, roof trusses are prepared in the required quantity, which then rise to the roof. Sometimes craftsmen assemble trusses on the roof. Collected one - installed, collect the next.

It should be noted that such farms have a significant mass. Lifting them manually is difficult and dangerous, so they use the services of a crane. And this increases the cost of construction.

Hanging trusses assembled on the ground

The most difficult thing is to set farms. All of them are installed at the installation site with a planned step, where they are temporarily fixed with jibs and props. Then a thread is pulled between the extreme farms. It must be set so that, firstly, it is stretched strictly along the horizon, and secondly, according to a design that is higher than the rest.

It remains only to raise the truss structures, which turned out to be below the stretched level. And the last - the installation of the crate, which will secure all the trusses into one truss system. Please note that at the bottom of the rafters will be fixed to the Mauerlat.

You may be interested! When the installation of the truss system is completed, the turn of roofing comes. From the article at the following link you can find out.

Rafter calculation

length of rafter legs;

the step of their installation;

section of the lumber used.

Everything is simple with the length, for this you will have to use the Pythagorean theorem, which is based on the formula: c 2 \u003d a 2 + b 2, where c is the hypotenuse of the triangle (this is the rafters), a and b are the legs. The latter are the height of the roof and half the width of the house. All parameters can be easily measured.

The length of the rafter is l 2 + H 2

It is more difficult with the installation step, because a lot will depend on the mass of the roofing material and the loads from natural precipitation. The larger both loads, the smaller the installation step. But, as practice shows, this parameter varies from 60 cm to 2 m. The latter indicator is used if corrugated board with large corrugation parameters, for example, H75, is used as a roofing material.

As for the section of the rafter legs, here, as in the case of the installation step, loads are taken into account, as well as the length of the legs and their installation step. Here the dependence is as follows: the greater the load, step and length, the larger the cross section.

Video description

In the video, the installation process of the truss system:

And one moment. Rafters for a gable roof are laid at a certain angle (indicated by the letter “a” in the photo). The slope is selected with the calculation of the choice of roofing material. That is, some coatings cannot be laid on roofs if the angle of inclination is less than required. Here are some ratios:

the minimum angle of inclination of the truss system for slate is 22 °;

for corrugated board - 12 °;

for metal tiles - 14 °;

soft tiles - 15 °.

The ratio of the roof slope to the type of roofing material

On our website you can find contacts of construction companies that offer a turnkey roof design and repair service. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Generalization on the topic

Gable roofs are traditional designs. But from the article it becomes clear that there are two truss systems that form the basis of the construction of roofs. The one that fits the size of the house is selected. As a selection criterion, the loads that put pressure on them are also taken into account. Therefore, it is important to correlate everything correctly, taking into account the nuances of construction processes.