How to make a gable roof truss system with your own hands. Do-it-yourself rafters: roof rafter systems and their installation

Installing rafters with your own hands is not as easy as it might seem at first. This dangerous and difficult work requires the mandatory presence experienced craftsman. Therefore, if the decision is made to install truss system, it is best to call a specialist for help. So you can protect yourself and not doubt the quality of the work performed.

Do-it-yourself installation of rafters is considered one of the most difficult and responsible processes when installing the roof of a house. After all, it is on the rafters that the bulk of the load falls. It is imperative to adhere to the rules, observe the order of work and pay attention to even the smallest subtleties.

Selection and preparation of wood

First you need to calculate for the roof truss system required amount the main material, which will be wood. The calculation is made based on the total area of the future roof. But it is unlikely that it will be possible to produce it on your own, so it is best to entrust this matter to specialists. In this case, it will be more profitable to pay the money than to redo everything and buy the material again.

FROM special attention You also need to consider the choice of wood. To make the roof truss system reliable, you need to choose only high-quality wood. It must be remembered that only a thick one is suitable for rafters. wooden beam. Ordinary boards are considered unreliable.

Much depends on the type of wood. Light woods are considered the most suitable for rafters, because too heavy wood will create a lot of pressure on the walls, which will gradually lead to their destruction. Lightweight and at the same time durable wood is the best option, and most suitable for such purposes conifers because they are light and have enough resins. As practice shows, it is the resinousness that gives the rafters high stability before adverse weather conditions.

wood requirements

There are certain criteria that you must be guided by when preparing a tree for rafters. Let's consider them in more detail.

In no case should the moisture content of the wood exceed 2.5%. And in order to make sure that the tree is ready for use as rafters, it is necessary to keep it in a dry, warm place for some time. Only the laid out wood will not be deformed in the future.
Everything wooden elements the future truss system must be subjected to fire and antifungal treatment. It is convenient to do this with the help of special compounds that are simply applied in a thick layer to the tree. Partially absorbed, such compounds create a protective film on the surface of the tree.
When selecting individual bars for elements of the truss system, it is recommended to take into account the type of wood. As a rule, wood of the first grade is used for rafters and their puffs of a hanging rafter system. The second grade is also suitable for the layered system, the third grade can be used with confidence for racks and struts of the truss system, which will serve as auxiliary elements.

A wooden beam for the construction of a truss system can be harvested independently or bought ready-made. When buying, be sure to check the quality of the tree, then make sure that there are not a lot of knots on the timber.

Rafter system for a gable roof

Any scheme for installing the truss system can be selected, depending on the type of roof. But consider the most common system that is successfully used for the construction of gable roofs, which are most popular in the construction of small residential buildings.

Preparing the elements

To install the rafters with your own hands, you should prepare the walls. To do this, on all load-bearing walls should be fixed wooden bars, which will exactly match their thickness. After that, a waterproofing material is placed on them, for which it is better to choose a thick roofing material. After it is fixed, you need to mark the location of the rafters. Care must be taken to mark the corners of the walls. Please note that if the markings are not the same at the ends of the same wall, the rafters will eventually be installed crookedly.

How to put the rafters correctly? First you need to make the first rafters, which will serve as a model. It is necessary to install long wooden bars on the outer parts of the walls of the house opposite each other and fasten them at the top. After that, lower them to the ground and take this model for the manufacture of all other rafters and their fasteners. Please note that there may be 2 or more samples, depending on which geometric shape house, and what are the distances between other opposite walls.

It is very important to always observe the same pitch of the rafters, which is chosen independently depending on the number of rafters. Practice shows that the smaller the step, the more reliable the truss structure will be. On average, the pitch of the rafters is about 50 cm.

It is best to use a timber a little longer so that there is always at least a small margin.

Each individual truss system is made according to the principle of an ordinary right triangle. That is, a timber of the required length is taken, its middle is marked. Then another bar is nailed to this middle perpendicularly. And after that, a second beam is nailed to such a beam, the length of which is equal to the length of the first. So it will turn out to make the nodes of the rafter system qualitatively. As a result, the first and last beams are connected at the top, forming an angle of 90 °. The number of such triangles is equal to the number of load-bearing walls. In this case, each triangle will be attached to a separate wall.

Rafter installation

But how to install the roof rafters correctly in order to avoid distortions in the future?

Installing rafters is no easy task. To do this, make markings on each wall for the installation of rafters, and then proceed with the installation. First you need to connect opposite walls planks - beds. After that, racks are nailed to them, and only then pre-made triangles are attached to them.

In order for all other rafters to hold well, it is also necessary to provide a run, which can be attached both on top of the puff and under it. This will turn out a kind of square, on which the rafter legs will already be attached. The photo clearly shows how the section of the truss system between two opposite walls will look like as a result.

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

frame gable roof by virtue of design features perfectly combines ease of installation and maintenance with reliability and durability. These and many other parameters make the construction of a gable roof practical and rational decision for private and commercial housing construction.

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

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

design variability;
simplicity in calculations;
natural flow of water;
the integrity of the design reduces the likelihood of leaks;
profitability;
preservation of the useful 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 primarily on its design.

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

The most common version of the roof device due to its simplicity and reliability. Due to the symmetry, a uniform distribution of loads on the load-bearing walls and the Mauerlat is achieved. The type and thickness of the insulation do not affect the choice of material.

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

A clear drawback is the impossibility of arranging a full-fledged attic floor. Due to sharp corners, “blind” zones appear that are unsuitable for use.

The device of one angle more than 45° leads to a decrease in the amount of unused area. There is an opportunity to make living rooms under the roof. At the same time, the requirements for the calculation are increasing, because. the load on the walls and foundation will be distributed unevenly.

This roof design allows you to equip a full-fledged second floor under the roof.

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

The design of the gable roof truss system

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

The locations of the elements are shown in the photo.

Mauerlat. Designed to distribute the load from the truss system to the load-bearing walls of the building. For the arrangement of the Mauerlat, a beam 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 estimated age of the structure. The most popular sizes are 100x100, 150x150 mm.
Advice. For a metal truss system, the Mauerlat must also be metal. For example, a channel or an I-profile.

rafter leg. The main element of the system. For the manufacture of rafter legs, a durable beam or log is used. The legs connected from above form a farm.

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

Rafter parameters are important. They will be discussed below.

puff- connects the rafter legs and gives them rigidity.

Run:

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

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

Rafter rack- 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 sloping roof and the arrangement of one room on attic loft- 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.

Strut. Serves as a support for the rack.

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

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

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

crate. It is intended for movement during construction works and fixing of roofing material. It is installed perpendicular to the rafter legs.

Advice. important purpose lathing - redistribution of the load from the roofing material to the truss system.

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

Advice. Be sure to add data on the passage of the ventilation shaft and chimney to the scheme of the gable roof truss system.

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

The choice of material for rafters

When calculating the material for a gable roof, you need to choose quality wood no damage or wormholes. The presence of knots for beams, Mauerlat and rafters is not allowed.

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

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

Calculation of the truss system of a gable roof

The calculation of material parameters is an important stage, so we present the calculation algorithm step by step.

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

1. Calculation of the load on the truss system

The load on the rafters can be of three types:

Permanent loads. Their action will always be felt by the truss system. Such loads include the weight of the roof, lathing, insulation, films, additional elements of the roof, finishing materials for . The weight of the roof is the sum of the weight of all its constituent elements, it is easier to take into account such a load. On average, the value of the constant load on the rafters is 40-45 kg / sq.m.

Advice. To make the margin of safety 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 the roofing material per 1 sq.m. roof area, did not exceed 50 kg.

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

In fact, the roof slope is like a sail and, given the wind load, the entire roof structure can be destroyed.

The calculation is carried out according to the formula: wind load is equal to the indicator for the region, multiplied by the correction factor. These indicators are contained in the 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 high-rise buildings, there are fewer loads. Standing separately Vacation home or cottage experience increased wind loads.

2. Calculation of the snow load on the roof

The calculation of the roof 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, which falls on 1 sq.m. roof area (according to SNiP 2.01.07-85) is in the range of 80-320 kg / sq.m.

The coefficients showing the dependence on the slope angle are shown in the photo.

Nuance. With a slope angle of more than 60 ° snow load does not affect the calculation. Since the snow will quickly slide down and will not affect the strength of the timber.

Special loads. Accounting for such loads is carried out in places with high seismic activity, tornadoes, 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 bearing capacity of walls and foundations

It should be borne in mind that the roof has a significant weight that can harm the rest of the building.

Determination of the roof configuration:

simple symmetrical;
simple asymmetric;
broken line.

The more complex the shape of the roof, the large quantity roof trusses and sub-rafter elements are needed to create the necessary margin of safety.

(banner_advert_2)

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

soft roof - 5-20°;
metal tile, slate, corrugated board, ondulin - 20-45 °.

It should be noted that increasing the angle increases the area of \u200b\u200bthe space under the roof, but also the amount of material. What affects the overall cost of work.

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

5. Calculation of the pitch of the rafters

The pitch of the rafters of a gable roof 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 number, you need to multiply by 2.

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 dwelling under the roof, the convenience of being in the attic, the consumption of material for the construction of the roof.

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

Parameter "c" is the hypotenuse of the triangle.

Advice. To the value obtained, you need to add 60-70 cm. For cuts and removal rafter leg behind the wall.

It should be noted that the maximum length of the beam is 6 r.m. Therefore, if necessary, the timber for the rafters can be spliced (building, joining, joining).

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

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

7. Calculation of the section of the rafters

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

load, we already wrote about it;

type of material used. For example, a log can withstand one load, a beam - another, a glued beam - a third;

rafter leg length;

type of wood used in construction;

distance 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 step of the rafters, the greater the load on one rafter pair. So, the cross section of the rafters needs to be increased.

Dimensions of lumber (beams and boards) for a gable truss system:

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

the thickness of the rafter leg and puffs 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 leg;

rack - 10x10 or 10x15;

bed - 5x10 or 5x15 (depending on the width of the rack);

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

Types of gable roof truss system

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

Consider each type in detail in order to make an informed choice.

hanging rafters

They are used with a roof width of not more than 6 r.m. The installation of hanging rafters is carried out by attaching the legs to the load-bearing wall and the ridge run. The design of hanging rafters is special in that the rafter legs are under the influence of a bursting force. Hanging rafters with a puff installed between the legs can reduce its influence. The puff in the truss system can be wooden or metal. Often puffs are placed at the bottom, then they play a role bearing beams. It is important to ensure that the puff is securely fastened to the rafter leg. Because a bursting force is also transmitted to it.

Advice.
The higher the puff is located, the greater the strength it should have.
If the puff is not installed, the load-bearing walls can simply “disperse” from the pressure created by the truss system.

Rafters

They are used in the arrangement of roofs of any size. The design of the layered rafters provides for the presence of a bed and a rack. Lying lying parallel to the Mauerlat takes on part of the load. Thus, the rafter legs seem to be inclined towards each other and are supported by the rack. The rafter legs of the layered system work only for bending. And the ease of installation also tips the scales in their favor. The only downside is the stand.

Combined

Due to the fact that modern roofs differ in a large variety of forms and complexity of configurations, a combined type of truss system is used.

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

Installation of a gable roof truss system

After the gable roof rafters are calculated, installation can begin. We break the process into stages and give a description of each of them. Get a kind step-by-step instruction containing additional information for 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 cabins, 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.

The material was prepared for the site www.site

Since the length of the Mauerlat exceeds standard sizes lumber, it has to be spliced.

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

How to connect the Mauerlat?

Washed down the bars is made only at an angle of 90 °. Connections are made using bolts. Nails, wire, wooden dowels are not used.

How to fix the Mauerlat?

The Mauerlat is installed on top of the wall. Mounting technology provides for several ways to mount the Mauerlat:

strictly in the center of the bearing wall;
offset to one side.

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

To protect the Mauerlat beam from damage, it is laid on a layer waterproofing material, which most often acts as an ordinary roofing material.

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

Methods for attaching the Mauerlat to the wall and rafters

Anchor bolts. Ideal for monolithic construction.

Wooden dowels. Are used for fellings from a log and a bar. But, they are always used with additional fasteners.

Staples.

Stud or armature. It is used if the cottage is built of porous materials (aerated concrete, foam concrete).

Sliding fastening (hinged). The bundle in this way allows you to ensure the displacement of the rafter legs when the house shrinks.

Annealed wire (knitting, steel). Used as additional mount In most cases.

2. Production of roof trusses or pairs

Installation is carried out in two ways:

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

assembly on the ground. That is, individual elements (triangles or pairs) for the truss system can be assembled at the bottom, and then raised to the roof. The advantage of such a system is faster work at height. The downside is that the weight assembled structure roof truss can be significant. To lift it, you need special equipment.

Advice. Before assembling the rafter legs, you need to mark up. It is very convenient to use templates for this purpose. The truss pairs assembled according to the template will be exactly the same. 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 are interconnected.

3. Installation of rafter legs

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

Advice. Since the slots on the Mauerlat will weaken it, you can only cut down on the rafter leg. To wash down was the same and fit snugly to the base, you need to use a template. It is cut out of plywood.

Methods for attaching the rafter leg are shown in the figure.

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

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

A twine is stretched between the fixed pairs. It will simplify the installation of subsequent rafter pairs. And also, it will indicate the level of the skate.

If the rafter system is mounted directly on the roof of the house, then after installing the two extreme rafter legs, the ridge support is installed. Further, half of the rafter pairs are attached to it.

It is worth noting that the opinions of professionals differ on this issue. Some advise using a staggered mounting order, which will evenly distribute the increasing load on the walls and foundation more evenly. This order involves the installation of one rafter in a checkerboard pattern. After part of the rafter legs is installed, the missing parts of the pair are mounted. Others insist that you need to do a consistent installation of each pair. Depending on the size of the structure and the configuration of the truss, the reinforcement of the rafter legs is carried out with props and racks.

Nuance. Additional structural elements are connected by cutting. It is preferable to fix them with building brackets.

If necessary, you can lengthen the rafter leg.

Methods for splicing rafter legs are shown in the photo.

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

4. Installing the gable roof ridge

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

Roof ridge device:

Method without using a support bar (see fig.).

A method using a rafter bar. Timber is needed for large roofs. In the future, it can become a support for the rack.

The method of laying on the beam.

More modern variety manufacturing a ridge knot can be considered the method shown in the photo.

Cutting method.

After the truss system is installed, we make a major fixing of all structural elements.

5. Installation of the roof lathing

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

The step of the lathing depends on the type of roofing material, for example:

under the metal tile - 350 mm (the distance between the two lower boards of the crate should be 300 mm).
under a professional flooring and slate - 440 mm.
under the soft roof we lay a continuous crate.

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

Conclusion

As you can see, despite the seeming simplicity, the installation of a gable roof truss system contains many pitfalls. But, based on the above recommendations, you can easily build robust design with your own hands.

The arrangement of a gable roof is considered a very practical and right decision in the construction of a residential or commercial building. This option combines the relative simplicity of execution and reliability, ease of maintenance and long service life. In this material, we will talk about how to install a gable roof truss system with your own hands, what are its varieties, and how to calculate the dimensions of its individual elements. Our step-by-step instructions will allow you to deal with any complications that may arise in the process.

A roof with two slopes has a whole list of advantages:

ease of calculation;
various options performance;
saving materials;
the possibility of natural outflow of water;
low probability of water leakage due to the integrity of the structure;
the possibility of arranging an attic or attic;
reliability and long service life;
ease of preventive maintenance.

Varieties of gable roofs

Consider the main types of roofs with two slopes, the truss system in which will differ slightly in execution.

Symmetrical gable roof

This is the simplest gable roof, however, the most reliable and in demand. Symmetrical slopes allow you to distribute the load on the Mauerlat and load-bearing walls evenly. In this case, the type and thickness of the insulation layer do not affect the choice of roofing material. Thick beams of rafters have a sufficient margin of safety, so they will not sag. In addition, spacers can be installed at your discretion.

Among the shortcomings this option it can only be noted that the angle of the slopes is too sharp, which makes it difficult to use the attic floor and creates “deaf” zones that have no use.

Roof with two asymmetrical slopes

If the angle of inclination of the slopes is made more than 45º, some unused areas of space can be used. It will even be possible to equip a living space in the attic. However, some additional calculations will be required, as the load on the walls will become uneven.

Broken roof with external or internal break

This configuration makes it possible to place a spacious attic or attic under the roof. However, in this case, more complex engineering calculations will be required.

The design of rafters for arranging a roof with two slopes

The design of the gable roof truss system assumes the presence of such components:

Mauerlat. It is a durable bar made of oak, pine, larch or other strong wood, which is laid around the perimeter on the bearing walls of the building. The purpose of the Mauerlat is to evenly distribute the load. The cross section of the bars is chosen based on their structure - solid or glued, as well as on the age of the building. The most commonly used beams are 100 × 100 or 150 × 150 mm.
rafters. The whole structure is created from such elements (read also: ""). Connecting at the top point, two rafters form a farm. They are made from logs or durable bars.
puff. This part serves to grip the rafters and ensure their rigidity.
Runs. In those places where the rafter legs are joined, a ridge run is attached, on which the skate will subsequently be mounted. And with the help of side runs, the frame of the rafters is given additional strength. The expected load determines the size and number of such elements.
Rafter rack. This is a vertical beam that partially takes over the weight of the roof. If the gable roof scheme is simple, then one such beam is placed in the center. For a long span, three bars may be required - one in the center and two on the sides. If an asymmetrical roof is being erected, then the location of such a beam is determined by the length of the rafter legs. under the rafters for broken roof racks are placed on the sides to make room for movement. Beams are placed in the center and sides if there are two rooms.
Struts. These are rack supports. If significant winds and precipitation are expected in winter period, install longitudinal, as well as diagonal racks.
Sill. A rack for rafters rests on it, and struts are also attached.

crate. The selected roofing material is attached to it, and you can also move along it during work. Fix the crate perpendicular to the rafters. Please note that the crate allows you to evenly distribute the mass of roofing material over the rafter system.

The scheme for installing a gable roof truss system will greatly facilitate everything construction works. How such a scheme will look depends on the type of roof.

Please note that the material for the truss system must be of the highest quality, treated with flame retardant and antiseptic agents. There should be no knots or cracks on the beams for rafters, Mauerlat and racks. Only a small number of knots are allowed on the crate, firmly seated in the wood.

Calculation of frame elements for a gable roof

The rafter system of a simple gable roof consists of a set of triangular trusses - this form gives the structure maximum rigidity. Such figures are the easiest to calculate. However, if the rays different shape, resulting in irregular rectangles. In this case, they are divided into more simple shapes and carry out calculations for each element separately. At the end, all data is summed up.

Please note that the more complex the shape of the roof, the more trusses and other details will be required to ensure its strength. All of them increase the total mass of the roof, which, if calculated incorrectly, can damage the load-bearing walls.

The load on the rafters according to the scheme

There are three types of load:

Constant. This is a value that will not change throughout the lifetime of the roof. This category includes a lot of roofing material, insulation, hydro and vapor barrier, battens, additional roof parts, as well as interior decoration attic. That is, the summed value of the mass of the elements will be the expected load. Her average value is 40-45 kg/m 2 , but not more than 50 kg/m 2 . It is desirable to provide a margin of safety equal to 10% of the total mass.
Variable. This refers to the intensity of precipitation, the load from snow and wind, which can vary significantly depending on the time of year or weather conditions.
special. This group includes extreme natural phenomena - earthquakes, tornadoes, strong winds. In these cases, the margin of safety is made significantly larger than usual.

We determine the slope of the slopes before installation

The slope of the slopes is calculated based on the type of roofing material:

soft roof - from 5º to 20º;
slate, ondulin, tiles, corrugated board - from 20º to 45º.

Note that the sharper the slope, the more material will be required for roofing.

Rafter pitch and length

As a rule, this value for residential buildings ranges from 60-100 cm. The type of roofing material and the total mass of the roof matter here. The number of rafters per slope is calculated by dividing its length by the step size plus one. For the entire roof, the value is doubled.

The length of the rafter leg is calculated using the Pythagorean theorem. If a maximum length a beam of 6 meters is not enough, it can be increased with other segments.

Rafter section

You can determine the cross section of the rafters based on the following data:

wood type;
type of material - logs, beams and so on;
rafter length.

Here are the approximate dimensions of lumber for a truss system for a gable roof:

mauerlat, section 10 × 10 or 15 × 15 cm;
puffs and rafter legs, 10 × 15 or 10 × 20 thick, in some cases a bar with a section of 5 × 15 or 5 × 20 cm is used;
for struts and girders - beams 5 × 15 or 5 × 20 cm, based on their width of the rafters;
racks - section 10 × 10 or 15 × 15 cm;
beds, section 5 × 10 or 5 × 15, based on the thickness of the racks;
crate, section 2 × 10 or 2.5 × 15 cm - the value is determined by the type of roofing materials.

Varieties of truss systems

There are two main types of truss systems for roofs with two slopes - hanging and layered. Let's describe each of them separately.

hanging rafters

The installation of a gable roof with hanging rafters is advisable only with a roof width of 6 meters. Such rafters are mounted on a ridge run on one side, and on a load-bearing wall on the other. They experience bursting forces, which is the main feature of a gable roof with hanging rafters. The puff for them can be made both from wood and from metal. If you install puffs from below, then they perform the function of load-bearing beams. It is extremely important to firmly fasten the puff, since it also experiences a bursting force. Tightening is needed, first of all, to prevent damage to the load-bearing walls - otherwise they may fall under the pressure of heavy rafter legs.

Rafters

In this case, the size of the roof does not matter. The assembly of this type of truss system assumes the presence of a bed and support posts. Part of the load is transferred to the bed, which is laid parallel to the Mauerlat. It turns out that the rafters are adjacent to each other at the top point and are additionally supported by a rack. In such a system, the rafter legs experience only bending force. They are mounted much easier than hanging ones. True, support racks are required.

Combined type

Often the roof is given a rather complex shape, which requires the construction of truss systems. mixed type. Professionals recommend making detailed diagram with calculations for each element of the truss system, so that in the process of work the data is always at hand.

Do-it-yourself installation of rafters for a gable roof

Laying Mauerlat on the walls

This element is attached to bearing wall along its entire length. If it's about log house, then the upper crown can serve as a Mauerlat. For buildings made of aerated concrete or brick, a Mauerlat equal to the length of the wall will be required. Sometimes this detail can be laid between the rafters.

With a lack of material length for the Mauerlat, several pieces can be spliced. At the same time, the edges are sawn at 90º and joined with bolts - wire, dowels or nails are not suitable.

There are two ways to lay a Mauerlat on top of a load-bearing wall:

symmetrically in the center;
offset in the desired direction.

Mounting of the Mauerlat is carried out on a pre-laid waterproofing layer of roofing material. This will protect the wood from rotting.

It is worth taking a responsible attitude to the process of attaching the Mauerlat, since in strong winds it must withstand a particularly heavy load.

As fasteners for Mauerlat, you can use the following consumables:

Anchors, which are indispensable for monolithic materials.
Wooden dowels. These parts are used in houses made of timber and logs, although they require additional fastenings.
Staples.
Reinforcement or special studs. This option is preferable for buildings made of foam or aerated concrete.
knitting or steel wire- This is an auxiliary fastener, used almost always.

Assembly of trusses or trusses

Farm assembly can be done using one of the following methods:

Beams for rafters are assembled and mounted directly on the roof of the building. This process is quite laborious, since all measurements, trimming and coupling of the bars will have to be done at a height. However, you can do it on your own, without the involvement of technology.
Trusses or truss pairs can be fixed to the ground, and then the finished elements can be raised to the roof of the building. On the one hand, this simplifies the process of installing rafters, and on the other hand, due to heavy weight construction, its rise to the top will require special equipment.

Please note that it is worth starting the assembly of truss pairs only after marking. And if you make a template in advance, for which you take two boards equal to the length of the rafters, and connect them together, then all pairs will turn out to be exactly the same.

Installation of rafters

After assembly and lifting to a height, the installation of gable roof rafters is carried out wooden house. To fix them on the Mauerlat, cuts are made at the bottom of the rafters. The first to install two trusses from opposite ends of the roof.

After that, a rope is pulled between the starting pairs, along which all the other truss trusses will be aligned and the ridge will be installed.

Now you can mount the remaining pairs in compliance with the calculated step between them. In cases where pairs are assembled directly on the roof, a ridge run is attached between the two end trusses. Subsequently, rafters are installed on it.

The order of installation of halves of rafters according to the opinions of professionals may differ. Some prefer to lay the bars in a checkerboard pattern so as not to overload the foundation and walls during work. Others tend to install pairs of rafters in series. Be that as it may, rafter legs may need props and racks - it all depends on the size of the roof and the shape of the trusses.

Skate mount

A ridge is an element that is formed by attaching rafters at the top point. As soon as all the details of the truss system for a gable roof are installed, it is necessary to perform a major fixing of all structural elements.

Lathing installation

The presence of lathing is mandatory in the construction of any roof. It not only supports the roofing material and allows it to be securely fastened, but also makes it possible to move along the roof during work.

The distance between the individual boards is chosen based on the type of roofing material:

soft roofing is laid on a continuous crate without gaps;
for a metal tile, a crate is needed with a step of 35 cm (between the two lower rows - 30 cm);
slate and corrugated board can be laid on the crate in increments of 44 cm.

Results

Thus, in order to assemble a truss system for a roof with two slopes, many nuances should be taken into account and any possible complications should be foreseen. We hope that our advice will help you cope with this difficult task and create a high-quality and durable roof for your home.

is not an easy task. This statement is obvious and understandable both for a professional builder and for a person who is only superficially familiar with the issue. There are no trifles in this business, and each of the stages of construction requires careful study and many years of experience. practical application acquired knowledge. And although, thanks to the development of technologies, the production of many materials and the improvement of tools, the work is greatly facilitated, some stages are a task that can only be carried out by a person who really understands the essence of the material.

It is especially important to figure out how to install the rafters on the roof. It is immediately necessary to make a reservation that if there is no proper experience in carrying out such work, then it makes no sense to take on them. But on the other hand, any experience is a matter of time, and the essence lies in knowledge, so it will not be superfluous to study the issue at least in theory.

First you need to say a few words about what a rafter is. So it is customary to call the main element of the roofing system, which is a long bars located vertically and at an angle relative to the walls. It is the rafters that are the original basis of the entire roof. Its main elements are mounted on top of the rafters, which means that mistakes made at the stage of installation of the truss system will lead to a violation of the installation technology and the rest of the roof. talking plain language, improper installation of rafters is the current roof. That is why the question of how to properly mount the truss system is of paramount importance when it comes to the roof of the house.

Types of rafters

Speaking about the installation of the truss system, it should be noted that there are two main technologies for completing the task.

Overhead rafters.
Hanging rafters.

These technologies are very different from each other, so it is quite true to consider each option separately and in more detail.

Rafters

Roof rafters are roof elements that, when installed, in addition to the fulcrum on the Mauerlat and among themselves, provide for the installation of special racks, which will also be supported. As a result, it turns out that the resulting spacer stresses and subsequent mechanical loads exerted by the remaining elements of the roof are evenly distributed and mutually compensated.

As for how exactly to install layered rafters on a house, it is useful to know here that there are several installation methods. The main differences relate to the methods of fixing the rafters to the Mauerlat and connecting the rafter legs to each other.

First, the bars used as rafter legs must be prepared. The point is that in the place of their contact with each other, it is necessary to choose half the thickness of the beam so that when the rafters are connected to each other, they are strictly in the same plane, without displacement.
In addition, at the junction of the rafter leg and the Mauerlat, special cuts can be made on the rafters, which will help ensure that the supports do not move apart.
At the top, the rafters, in addition to fixing with each other, are attached to an additional support - a longitudinal beam, which is laid across the direction of the rafters. Thus, the rafters are firmly fixed already.
Further, the rafter legs can be additionally pulled together at the top or bottom, and possibly in both places, if the situation so requires.

If we talk directly about the methods of fastening the rafters, then there are also many options. For these purposes, one can also use construction staples(convenient for attaching rafters to the Mauerlat), and a variety of auxiliary struts and ties, as well as steel mounting plates and the like. Self-tapping screws, studs, wooden wedges, the brackets mentioned above, and in general everything that the situation and experience in carrying out such work will allow.

hanging rafters

Another option for manufacturing a truss system is the installation of hanging rafters on the house. By by and large the process of installing supports using this technology may resemble the one described above, but this is not entirely true, for a number of reasons, one of which is that for the installation of hanging rafters it is not necessary to install a central support like a longitudinal beam, as is necessary in the case described above. The rafters are connected to each other and to the Mauerlat, so it turns out that they seem to be hanging on the frame of the house. This somewhat simplifies the work on the technical side and allows you to mount the truss system on houses that do not have a central load-bearing wall.

As for how to install hanging type rafters, this happens in in general terms in the following way:

First, the bars are connected to each other. At this stage, it is necessary to ensure that the joints are even and strong.
Then I set the formed rafter legs on top of the log house and fix it.

It is important to understand that this process may seem simple only in words, since it entails not only the application of physical effort, but also the use of a sufficiently large amount of knowledge and skills, which not everyone can boast of.

The fastening of the rafter legs to each other can be carried out, as in the first variant, in several ways. For example, you can pull the rafters together with a horizontal bar at the bottom, just above the Mauerlat level, or vice versa, equip an additional screed at the top, closer to the convergence of the rafters. And you can combine options, which will only add strength to the structure. But here it is important to remember that any excesses are not good for the cause.

The more additional elements the truss system will have, the more weight the entire roof will have, which means that the load will be greater both on the walls and on the foundation.

Another way to further strengthen the hanging rafters is to equip them with a special supporting support, called the "headstock". First, the rafter legs are pulled together with a beam below, and then, using this beam as a support element, a vertical support is installed. In addition to the "headstock" you can use angular spacers, but it is important to remember that for the reasons described just above, excessive enthusiasm for the supports is inappropriate.

Concluding the above, we can add that it is, in principle, possible to put the rafters with your own hands. However, for this it is necessary to have both knowledge and experience, and if they are not, then better job entrust to professionals, and to acquire knowledge, you can limit yourself to the “position” of an assistant. Among other things, as a source additional information on topics of interest, you can use the relevant videos that will help you understand the essence of the issue and clearly demonstrate the upcoming process.

Video

Watch Larry Hohn's educational film on how to build a roof:

One of the most important stages in the construction of a house is the installation of the roof, because for this you need to choose best option rafter locations. To build a roof yourself, you need to consider several options for installing the roof, as well as learn about the sequence of actions performed.

Rafter system design

For each house, a rafter system should be designed that is suitable for this particular building. If this is not done, then the load will be distributed unevenly, which can lead to a skewed roof.

For creating right project it should be taken into account that:

If it is necessary to lay the insulation, the truss system must be done in such a way as to facilitate further work. Heaters are usually sold in widths
1200 mm, so the step between the rafters should be selected taking into account precisely this characteristic. Otherwise, the insulation will have to be cut off constantly.
The power of the supports is determined by the cross section of the beam from which they are made. Attention is also drawn to the condition of the wood. It is better to choose resinous bars, as they are used longer.

Wood pretreatment and preparatory work

Before starting work, the timber must be treated with special compounds so that it is protected from the effects of microorganisms and fire. Antiseptic is applied prior to installation. The composition should be applied with hard brushes.

In order for the composition to protect the wood for as long as possible, it is applied in two layers (before this, the material is dried). Installation of rafters on the roof occurs only after the complete drying of the applied compositions.

Preparation begins with checking all walls and ceilings, as well as taking measurements. If in some places the wall deviates from the horizontal, this is corrected by using cement screed. If the house is built of wood, irregularities are removed by installing wood linings.

To make work easier, install scaffolding. They should be at roof level.

Mauerlat

Mauerlat is the base on which the load acts, therefore it is from him that the construction of the truss system begins. The location of this element is carried out in such a way as to evenly distribute the load from each support. This element of the truss system is a log or beam that is laid on external walls. This option for creating a truss system is the most effective.

Important ! so that moisture on the Mauerlat does not reduce its service life, two layers of roofing material are laid under the timber.

A bar with a cross section of 10X15 cm is used as a Mauerlat. This element is laid after the completion of the construction of the walls. After laying before fixing, the horizontal is determined using building level. The most popular method of fastening is the use of anchor bolts.

The bolts are fixed on the reinforced belt during the completion of the wall construction. After that, holes are drilled in the beam, which coincide with the location of the bolts.

Types of rafters

Before building a rafter system, it is necessary to determine the type of rafters used. They are divided into 2 types:

on the slope;
hanging.

If the building is small, only simple rafters are used, which are attached to the Mauerlat and interconnected by a crate. If the structure is large (for example, a residential building), then more construction is carried out. complex design roofs. Before installing the rafters of a gable roof with your own hands, the slope is selected, which is determined based on the expected load from snow and wind.

Hanging rafters are structures that are supported in only two places. This means that with such a scheme, intermediate supports are not used. Distinctive feature this type of rafters is to create a bursting load on the walls of the building. This type of frame is used most often in the construction of residential buildings. If the angle of the roof slope is less than 45 degrees, then additional elements are installed. Most often, puffs are used that connect the rafters to each other.

Important ! The higher the tightening, the stronger it should be.

For the construction of a layered truss system, a third support is required, which is usually another load-bearing wall.

Preparing for installation

Before starting work, prepare necessary tools and expendable materials. To avoid dangerous situations, it is better to build scaffolding near the house. Do not forget about personal insurance.

For work you will need:

timber, the cross section of which is 15X15 cm;
waterproofing material;
adjustable wrench, which will be needed when tightening the anchor bolts;
building level;
a hammer;
drill;
nails.

For rafters, a bar is selected, the section of which is 50X200 mm

Installation steps

Installation of gable roof rafters is as follows:

lifting the beam to the roof;
sawing out a part of the lower ends of the rafter legs in such a way that a reliable connection is formed in contact with the Mauerlat;
connection of paired rafter legs;
installation of extreme rafters and their connection with the help of a ridge run.

In order for the rafter legs to be connected to each other more reliably, half of their thickness is cut out in the place where they are connected. Cutting parts of the rafters takes place on the ground, since it is inconvenient to do this on the roof.

Before installing the rafters, the Mauerlat is marked in order to observe the selected step between the supports. Usually the distance between them is one meter. The same marks are applied to the ridge run.

Methods for installing rafter legs on walls

If the rafters are installed on brick walls, they are fixed with a device called a "ruff". It is a metal element that is driven into the wall from the inside of the building and covers the rafters with a loop.

On all structures that do not shrink, fastening occurs by cutting out recesses in the rafters for attaching to the Mauerlat. Attachment occurs with nails or corners.

Important ! between the rafter system and the pipe there must be a distance of at least 130 mm.

Strengthening the rafter legs with additional elements

If the rafter system has already been created, but the owner of the house has learned that it is not adapted to the loads that will affect it, he needs to strengthen the rafters. This happens by inserting additional wooden beams, which have the name of help. Attachment to the rafters occurs with the help of metal clamps or toothed plates.

Also, strengthening can occur when there is too much load in the middle of the rafters, which threatens to break the timber. To avoid this, additional overlays are created on the connection area with the support. New part truss system can be built both above and below the old roof elements.

If the installation is higher, then in addition to strengthening the roof, a change in slope also occurs. This method avoids the loss of time for a complete replacement of the rafters and involves securing new rafter legs to those that have already been installed. The process of changing the roof begins with the removal of the crate. After this, the installation of new elements takes place, which, by the method of connection, do not differ from the old truss system.

In some cases, it is necessary to strengthen the bottom of the rafter leg. This is necessary in situations where the Mauerlat begins to rot and become less reliable. To strengthen the rafter legs, struts are attached, resting against the Mauerlat or an additional bed. For more reliable fastening, notches are cut out on the rafters. Additional elements fastened with nails.

Ways to strengthen damaged structures

Methods for restoring damaged parts of the roof include:

installation of wooden linings;
creation of bar prostheses;
the use of overlays based on the beam.

The first method is used for single damage to the rafter legs. To strengthen the element of the truss system, wooden linings are attached and fixed with bolts or nails. Additional elements must rest securely against the Mauerlat and be fixed in this position by twisting.

Bar prostheses are more often used for massive damage to rafters. To strengthen, first, temporary supports are installed so that the rafters are in a fixed position. After that, the damaged parts of the structure are cut out. Then a prosthesis is put on, which rests on the Mauerlat.

The overlays that rest on the beam are used when part of the Mauerlat has rotted. In this case, this section is cut out. To support the rafter leg, an additional reinforcing brace is created, which abuts against a pre-fixed beam. The beam is located below the Mauerlat, if the wall structure allows it. In order to make a crate in a place where there is no longer any support, an additional board is attached, on which the crate is attached.