One of the important stages of any construction is the construction of the roof of the building, the basis of which is the installation of the rafter system. The uniform distribution of the weight of the roof on the frame, the reliability of the roof and the duration of its operation as a whole will completely depend on how correctly the rafter pitch is chosen, i.e., the distance between them. With any minor calculation error, damage and collapse of the entire roof can occur.

Collection of required design values \u200b\u200bto establish the rafter pitch

The rafter system includes the following components:

• farms;
• ridge and side runs;
• mauerlat;
• diagonal elements.

Farms consist of a crossbar, the basis, rafter legs, binding and fixing elements. The rafters are beams located along the slopes, the lower ends of which are connected to the Mauerlat, and the upper ends to the girders.

The rafter pitch is the exact distance between the two rafter legs.

In order to get the exact indicated value, you first need to find out the values \u200b\u200bof some values \u200b\u200bimportant for this.

All calculations on the roof covering system should be done correctly at the design stage of the house. You can carry out such a responsible matter yourself or entrust it to specialists. The more accurate the calculations, the stronger the base for the roof.

To correctly make all the required calculations, including the size of the rafter pitch, you need to know:

• permanent and temporary loads;
• their size;
• ramp angle;
• type of roofing;
• rafter manufacturing material;
• type of roof.

One of the indicators that must be taken into account when calculating the rafter pitch is considered constant and temporary loads. These include:

• weight of roofing and truss structure;
• weight of the roof interior;
• snow cover weight;
• the weight of the person performing the roof maintenance.

It should be noted that these data are taken in special tables developed by scientists, depending on climatic zones, for various territorial regions.

The slope angle can be determined by knowing the length of the wall of the house and the height of the roof. The steeper the roof, the more it is installed, since the load on such roofs will be transmitted mainly to the bearing walls. After further calculations, the length of the rafters is easily calculated. Most often they have standard values: 4 and 6 m.

For the manufacture of a roofing system, coniferous wood is well suited. Lumber should be of high quality, without knots, rot. Before work, all wooden elements must be treated with antiseptic special compounds.

The step of the rafters will also depend on the type of roof, i.e., on the functional features and its shape. The size of a simple and complex roof will be different.

How the type of roofing will affect the step of the rafters should be considered in more detail.

General technology for calculating the distance between rafters

Having made all the necessary measurements, it is possible to make a constructive calculation of the rafter pitch. Based on practice, this indicator is in the range from 0.6 to 1.0 m.

To independently perform this calculation correctly, you must adhere to the following technology:

1. The total length of the roof slope is taken.
2. The optimal step of the truss truss is selected.
3. The length of the slope must be divided by the step of the rafters.
4. The unit is added to the obtained value.
5. To get an integer, the result is rounded up.
6. This calculation is the number of trusses (truss legs) located on one slope of the roof.
7. Now the entire length of the roof slope is divided by the obtained value, showing the number of farms. This determines the pitch of the rafters.

It should be noted that this calculation is made in the center of future rafters. However, the calculations cannot be considered accurate and constant. In each case of building the roof of a house, the angle of the roof slope, the features of the selected roofing material, and other indicators are taken into account. In this regard, it is necessary to consider the features of choosing the step of the rafters for the most common roofing materials: metal and ceramic tiles, corrugated board, slate and ondulin.

Features when choosing the distance between the rafters for metal and ceramic tiles

Metal tile as a roofing is extremely common in both urban and suburban construction. The design of the roof truss system when using a metal tile will not differ much from the general scheme. However, due to the fact that this building material has a small weight, rafters and other elements of the system can be taken of a smaller cross section, i.e., with a lower margin of safety. The distance between the rafters when using a metal tile is 60-95 cm. Performing all installation works on a roof made of a metal tile is much easier than from other roofing materials. A feature of the device of the crate of this material is that the board near the cornice should be about 1.5 cm thicker than the others. Usually, the cross section of rafters made of metal is 50x150 mm.

Ceramic tile is a roofing material having significant weight, which is 10 times the weight of a metal tile. In this regard, it is necessary to more thoroughly approach the calculation of the roof truss system. should be increased slightly - up to 60x180 mm. The average distance between the rafters for coating of ceramic tiles is set in the range of 0.8-1.3 m. The angle of the slopes of the slopes must be taken into account: the distance between the rafters is greater, the higher the roof.

The length of the rafter legs in this case will have a strong influence on the result.   The distance between the rafters decreases with increasing length. With their long lengths, increased loads can occur on the deflection, which can be significantly reduced if you additionally install a system of struts, props and other elements.

Features when choosing the step of the rafters for slate, corrugated board and ondulin

The most common roofing material is slate. This is due to its low cost, ease of installation, the ability to replace when damaged individual elements of the roof.

Features of the crate for slate is its thinned type, consisting of any type of board or timber, but with a mandatory cross-section of at least 30 mm. This is necessary for the correct and high-quality distribution of the weight of the slate on the crate.

The optimal distance between the rafters when combining the load from the weight of the slate sheets should be 80 cm. You should constantly take care of the margin of safety of the rafter system, which may be due to various unforeseen circumstances. Otherwise, its installation under a slate roof does not differ from other options.

Now you should pay attention to some features when installing the rafter system for such roofing materials as corrugated board and ondulin.

The weight of corrugated board and ondulin is much lighter than that of ceramic tiles or slate, so the technology for installing rafters for these materials is practically no different from installing a metal tile. The distance between the rafters for the roof from corrugated board is 60-90 cm, and from ondulin - 60-100 cm.

If it is necessary to increase the distance between the rafter legs, it is necessary to strengthen the design of the system with the transverse elements of the crate.

The device of the crate for corrugated board is very similar to the device of the crate of metal tiles. It is important to remember that in this case, the last board should have a slightly larger thickness than all the others.

A feature of the installation of the crate for ondulin should be considered the need for its continuous type for high-quality resistance to various loads. In some cases, a thinned-out crate can also be used, but then the step between the rafters should be no more than 30 cm.

Thus, knowing how to make all the necessary measurements, knowing the basics of installing the rafter system for the basic materials for the roof (tiles, decking, slate and ondulin), you can correctly calculate the distance between the rafters.

It is pointless to argue about the importance of a roof for any building. No wonder over the entire history of mankind, more than a dozen different types of roofs were invented, from simple to quite complex in design and construction. An important element in planning the construction of the roof is the step between the rafters - strong bars, which are the basis of the structure. This will be discussed in this article.

The distance between the base of the roof slopes is not a constant and depends on the following components:

• type of roof;
• slope angle;
• the type of roofing material proposed for installation;
• rafter section sizes.

Before proceeding with the process of erecting the upper structure of the house, a calculation should be made, determining the optimal distance between the rafters.

Gable Roof Step

The most common in our country are gable roofs. They are a structure having two parallel planes, with an angle of inclination relative to the horizon from 20 to 50 degrees.

With insufficient slope of the gable roof in snowy areas, there is a danger of accumulation of large snow masses, which can lead to destruction of the structure. An increase in the angle of slopes in regions with a predominance of strong winds is also fraught with a high load and the danger of breaking not only the roof, but the entire structure as a whole.

Roof system

Most private homes have an exploited roof space called the attic. This design is characterized by increased ramp height, which is caused by the need to create a living room of convenient height. As a rule, the slopes of the attic roof are broken, having a varying angle of slope. For their installation, a double rafter system is used.

The steepness of the lower slopes of the attic roof significantly exceeds the slope of their upper extensions. The plane load perceived by them is not great. Due to this, the rafters in the lower part can be installed with the maximum pitch. The upper ridge slopes are recommended to be mounted with a reduced gap from each other.

Rafters in a pitched roof

For household buildings and some private houses, roofs with one slope are used. Due to the limitation of the angle of inclination, high pressure is exerted on them. Experts recommend using lumber of increased cross-section for rafters of a pitched roof, with the installation of a minimum pitch from each other.

When calculating the distances at which roof beams are installed, special attention should be paid to the amount of snow load in a particular area. With a small slope, this characteristic is of great importance. Roofing material for such roofs is better to choose with a minimum dead weight, which will reduce bending load.

Hip roof truss system

The most difficult in construction is the rafter system of the hip roof. This type is called four-slope, since the roof is formed not only by side, but also by additional end slopes, where the rafters are installed not on the ridge, but on corner bowstrings. This makes special demands on the organization of the roofing frame.

Under the hip roof, the attic is not often arranged. This is due to the small angle of the rafters and the roof as a whole. In the case of an increase in the angle of the slopes to the horizon, the distance between the rafters is increased, with a decrease, on the contrary. An additional aspect of the calculation is the roofing material used.

The dependence of the pitch of the rafters on the roofing material

In addition to snow and wind loads related to variables, a constant (static) also acts on the roof, the force of which depends on the roofing material used. It is no secret that various types of roofs have their own mass, which can differ by 10 or more times.

The right choice of material affects not only the upper, but also all other parts of the construction of a residential building and other buildings. Not without reason, when designing the foundation, it is necessary to determine the choice of roof in advance.

Roofing

Currently, one of the most common roofing materials is a profiled sheet, produced in galvanized or followed by a polymer coating. The distinguishing features of the profiled sheet include the following parameters:

1. High corrosion resistance;
2. As a result, a long (over 15 years) life;
3. Easy installation even without the necessary qualifications;
4. Low sheet weight (weight 1 m 2 is 4-5 kg).

Since this roofing material does not exert a high load on the rafter system, the distance between the elements is selected as high as possible for a particular angle of inclination. In addition, the profiled sheet does not require high strength characteristics from the roof lathing. All this together allows you to minimize the total load on the foundation and walls.

Roofing

The second common type of steel roofing material is metal. This type of profiled sheet, successfully imitating natural clay material, but with a lower mass (10 or more). A feature of rafters for metal tiles is a smaller section size.

Choosing at what distance to install the rafters, you should first be guided by the dynamic load. Like the professional sheet, the metal tile is not demanding on the size of the rafter legs and is well mounted on the crate from an inch board of coniferous species. All this makes a metal roof low-cost.

Rafter system for ondulin

In the 21st century, wavy sheet materials were replaced by a more durable and lightweight analogue - ondulin. Among others - the most lightweight material. The mass of the sheet does not exceed 6 kg.

The small thickness of the ondulin sheets at slope angles of less than 15 ° requires the arrangement of a continuous crate of plywood sheets, for example, which will require an appropriate rafter step. This should be noted when calculating.

Slate roof

Not so long ago, wavy material from an asbestos-cement mixture called slate was widespread. High mass and fragility are the main disadvantages, however, to this day he finds his fans in the construction of various outbuildings.

A high mass, comparable with the weight of clay tiles, will not allow the same rafter system to be used as under a metal tile. Building standards determined the minimum angle of the slope of the roof from slate to 22 about or more. Otherwise, the load from the material itself and the rafter system with the crate exceeds the permissible parameters. The pitch of the inclined bars, as well as their cross section, are selected individually in each case.

Polycarbonate on the roof

In recent years, more and more often, on the roofs of porches and arbors, an artificial polymer material - polycarbonate - has been used. Available in two versions - monolithic and cellular. The first in its properties is similar to ordinary quartz glass, but significantly exceeds it in strength. The second has less mechanical properties, but high thermal insulation and light transmission.

Cellular polycarbonate is standardly much lighter than a monolithic fellow. It is used as a roof without the use of a battens, provided that the step does not exceed ½ of the width of the sheet of material. The high strength of the monolithic analogue also allows you to avoid transverse rafters of the elements. Sufficient flexibility allows you to cover semicircular roofs on a metal frame, the step of which does not exceed 0.9 meters.

Thematic Material:

Rafters under the soft roof

The original pattern can be obtained through the use of soft roofing materials creeping with an adhesive layer. Which are installed on a continuous crate of plywood or OSB. The rafter pitch should allow the sheets to be fixed, so it is chosen as a multiple of ½ of the width. Given the standard plywood dimensions of 1520x1520 mm, the center distance between the rafters will be: 1520: 3 \u003d 506 mm.

Step rafters for insulation

Installation of residential under-roof spaces is often combined with the laying of insulation sheets in the rafter gap. The most common are slabs with dimensions of 600x1000mm. We use these parameters as starting points.

The scheme of calculating the step of the rafters

According to construction standards, the pitch of the roof rafters is in the range of 0.6 - 1 meter. Its final calculation is performed according to a simple formula, depending on the total length of the roof. To calculate, you must perform the following list of actions:

1. determine what distance should be between rafters for your specific construction conditions. The directory determines the magnitude of wind and snow loads in the area.
2. the length of the roof is divided by the desired distance, adding one. The result will be equal to the number of rafter legs that are installed on one roof slope. In the event that the value is not an integer, it is rounded.
3. the length of the roof is divided by the number of rafters calculated above, we get the final step in meters.

For example, with a slope of 30 degrees, the maximum distance between the rafters of a gable roof under a metal tile is 0.6 measure. The length is assumed to be 16 meters. Consequently:

1. 16:0,6+1=27,66;
2. rounding the result, we get 28 rafters per slope;
3. 16: 28 \u003d 0.57 meters - the center distance of the rafter legs for these specific conditions.

As you can see, the calculation technology is not complicated, but this is only an approximate scheme. Taking into account many other parameters mentioned above can make certain adjustments.

The design of the gable roof for private houses is most often chosen, since it is the best option for ease of installation and ease of use, for strength and reliability, as well as for the style solution. The gable roof is also called gable roofing and has two slopes that can be located in relation to each other at the same or different angles, that is, it can be an isosceles or versatile triangle. The latter option is increasingly seen among new buildings, as it becomes a fashionable style decision. And, in addition to originality, such a roof has some positive features that simplify its operation.

A similar type of rafter system can be used for all types of roofing materials, but the lath, fixed to the rafters, for each of the coatings has its own parameters.

Gable roof: the rafter system under which has its own characteristics, must be carefully studied and calculated ahead of time, before purchasing materials and carrying out its installation. Let's try to understand these issues.

Varieties of gable roof structures

First you need to figure out what designs of gable roofs are, as you have to choose the most suitable for a particular building.

• Simple equilateral gable design

This version of the gable structure can be called traditional and the most used, as it is easy to install and maintain, and also characterized by durability and reliability.

Symmetry in this system helps to achieve a uniform load on the Mauerlat and load-bearing walls. With the right choice of the cross-section of the beam for arranging the rafter system and the Mauerlat, these parts will provide the necessary margin of safety for the long-term operation of the roof. Correctly installed racks, struts and tightenings will give additional reliability to the design.

The disadvantage of this system for arranging inside the attic space of the premises is that after installing the walls and ceiling a large area is occupied by blind areas in the corner areas of the structure, which remain unused.

• Simple asymmetric gable design

Asymmetric gable structure differs from the traditional system in that its slopes are located at different angles. So, one of them is usually more than 45 degrees, which allows you to increase the usable area of \u200b\u200bthe attic space, in which it is quite possible to equip a living room, of course, with proper insulation.

Another important advantage of this design can be a smaller slope, which is recommended to plan on the leeward side of the structure, where a lot of snow is always collected on the roof. A small in size, but with a large steepness slope will not delay large snowdrifts on its surface.

The disadvantage of the asymmetric design can be attributed to its more complex calculation to achieve an even distribution of the load on the walls of the house.

• Broken gable structure

This gable roof system can be called a rarity, although due to this arrangement of slopes in the attic space, a rather large room is formed, which can be used for a residential or utility room.

In addition to such a rafter system, a mansard option for installing rafters can also be attributed to a broken gable structure.

3 - Stand mounted on the bench.

4 - Rafter.

5 - Crate.

The vapor system differs from the suspension system in that it is installed on a building with internal capital partitions. The main internal walls are used to fix a lodge on them, on which racks are installed that support the ridge run, with which the upper ends of the rafter legs are fastened. Then, on the rafters, the boards of the crate are fixed.

This design is more popular than hanging, as it is reliable and easy to install.

rafter mounts

Hanging rafter system

The scheme of the hanging rafter system looks like the one shown in the illustration, and includes the following main elements:

1 - Bearing walls.

2 - Mauerlat.

3 - Rafter.

4 - Crate.

5 - Tightening (bolt).

The hanging rafter system is mounted on two external load-bearing walls, on which the Mauerlat is previously fixed. This version of the roof can only be applied if the distance between the bearing walls is not more than 7000 mm, since there is no additional support for the roof truss structure except for them. Such a system is usually equipped with puffs supported by slopes - these elements will remove part of the load from the walls of the building.

In addition to overhead and hanging systems, there are combined options that include individual elements of one and the other design.

When the rafter system is selected, it is recommended before buying materials to draw up a detailed drawing of the roof with the dimensions put down - it will be easier to calculate the amount of everything needed and the amount for their purchase. In addition, such a scheme will greatly help to carry out installation work. But in order to draw up a drawing, some

How to calculate the parameters of a gable rafter system

Correctly calculate the parameters of the elements for installation work is very important. To do this, it is first recommended to make a list of everything necessary and make the calculation step by step. All calculations should be made with a margin of 10 ÷ 15%, avoiding excessive savings, which would be at the expense of quality and structural strength.

If it is decided to do this part of the work yourself, you must always consult the technical documents developed by specialists, for example, posted in SNiP.

The main directions of calculation will be three interrelated quantities - the slope of the ramp, the height of the ridge over the ceiling and the length of the rafter legs. Further, having linear parameters, it will be necessary to determine the cross-section of the material for the rafters. But it, in turn, already depends on the loads falling onto the rafter system.

The load on the rafter system

The loads on the rafter system are divided into three categories:

• Constant loads. This category includes those that will constantly keep the rafter system in tension - insulation, if provided, roofing, windproof, hydro- and vapor barrier films, fasteners, finishing materials for the inside of the attic. The weight of all the elements and materials necessary for the roofing “pie” is summed up, and on average, the optimal value of 40-45 kg / m² should be obtained. It is advisable to calculate the materials in such a way that the weight of 1 m² does not exceed 50 kg / m², especially if a roof system with hanging rafters is used.
• Short-term loads.   Such loads occur periodically and can have different effects on the design. These include the following effects:

—   weight of people during repair work;

—   climatic temperature effects;

—   possible loads from ice.

These external loads are highly dependent on the characteristics of the region of construction. In addition, their value directly depends on the steepness of the slopes. So, for example, on gentle slopes, the snow load will play a decisive role. With an increase in the steepness of the roof, the influence of snow pressure decreases, but the dependence on the wind effect increases. On slopes with a steepness of over 60 degrees, the snow load is completely deducted, but the roof windage increases significantly, and the wind becomes the dominant external influence.

Data for calculations can be found in SNiP 2.01.07- 85 * “Loads and impacts” in the sections “Snow loads” and “Wind loads”. At the same time, it is necessary to take into account not only the region where the house is located, but also the place of its construction - a lowland or hill, a separate building or surrounded by other buildings.

A convenient algorithm for calculating the loads will be given below.

• Special loads. This category includes factors such as seismic effects, hurricane wind, deformation processes due to subsidence of the soil, which are usually called force majeure circumstances. It is impossible to foresee everything, and in order for the roof to withstand all these tests, it is recommended to lay an additional margin of safety when purchasing materials and installing the structure.

If the roof will be installed on an old building, it is necessary to calculate the bearing capacity of the foundation and walls, since the new roof can have more weight than the old one. Such calculations can be carried out professionally only by specialists, but such calculations must be performed without fail, otherwise you will have to not only change the roof, but also make repairs to the entire structure. In this case, specialists will need to provide a roof design in which all its parameters will be indicated.

The angle of inclination of the slopes of the rafter system and the height of the ridge

The angle of the roof slopes is determined by the choice, since each of them requires a personal calculation. Often the manufacturer of a particular brand of coating gives the necessary recommendations, but if we talk about general requirements, for example, for our case - metal tiles, then for it the slope angle should be at least 20 degrees.

An increase in the slope angle will significantly expand the attic space, but for the construction of such a roof more construction materials will be required and, of course, the cost of construction will increase significantly.

So, any gable roof system, whether symmetrical or not, can be represented as a triangle.

Its peaks:

- point "a"   - this is the external intersection point. The angle “A” adjoins this peak, which determines the steepness of the roof slope.

- point « b "   - the top of the skate.

- point "from"   - the intersection of the vertical line from the ridge with the overlap or just the top level of the wall.

The known initial value is « D "   the length of the base of the triangle. For a symmetrical roof, this is half the span. For asymmetric options - it may be different, it is not difficult to determine.

"N"   - the height of the ridge above the base (overlap);

« L "- the length of the rafter leg, which, if desired, can be increased by "M"to form a cornice overhang.

According to the known trigonometric relations:

H \u003dD × tgA

Thus, it is possible either to determine the height of the ridge from a given angle A, or, conversely, by planning a certain height of the attic in advance, to determine the slope of the ramp.

All this makes it easy to make the calculator below. By changing the value of the angle A"   you can come to the optimal height value " N ".

It is pointless to argue about the importance of a roof for any building. No wonder over the entire history of mankind, more than a dozen different types of roofs were invented, from simple to quite complex in design and construction. An important element in planning the construction of the roof is the step between the rafters - strong bars, which are the basis of the structure. This will be discussed in this article.

The distance between the base of the roof slopes is not a constant and depends on the following components:

• type of roof;
• slope angle;
• the type of roofing material proposed for installation;
• rafter section sizes.

Before proceeding with the process of erecting the upper structure of the house, a calculation should be made, determining the optimal distance between the rafters.

Gable Roof Step

The most common in our country are gable roofs. They are a structure having two parallel planes, with an angle of inclination relative to the horizon from 20 to 50 degrees.

With insufficient slope of the gable roof in snowy areas, there is a danger of accumulation of large snow masses, which can lead to destruction of the structure. An increase in the angle of slopes in regions with a predominance of strong winds is also fraught with a high load and the danger of breaking not only the roof, but the entire structure as a whole.

Roof system

Most private homes have an exploited roof space called the attic. This design is characterized by increased ramp height, which is caused by the need to create a living room of convenient height. As a rule, the slopes of the attic roof are broken, having a varying angle of slope. For their installation, a double rafter system is used.

The steepness of the lower slopes of the attic roof significantly exceeds the slope of their upper extensions. The plane load perceived by them is not great. Due to this, the rafters in the lower part can be installed with the maximum pitch. The upper ridge slopes are recommended to be mounted with a reduced gap from each other.

Rafters in a pitched roof

For household buildings and some private houses, roofs with one slope are used. Due to the limitation of the angle of inclination, high pressure is exerted on them. Experts recommend using lumber of increased cross-section for rafters of a pitched roof, with the installation of a minimum pitch from each other.

When calculating the distances at which roof beams are installed, special attention should be paid to the amount of snow load in a particular area. With a small slope, this characteristic is of great importance. Roofing material for such roofs is better to choose with a minimum dead weight, which will reduce bending load.

Hip roof truss system

The most difficult in construction is the rafter system of the hip roof. This type is called four-slope, since the roof is formed not only by side, but also by additional end slopes, where the rafters are installed not on the ridge, but on corner bowstrings. This makes special demands on the organization of the roofing frame.

Under the hip roof, the attic is not often arranged. This is due to the small angle of the rafters and the roof as a whole. In the case of an increase in the angle of the slopes to the horizon, the distance between the rafters is increased, with a decrease, on the contrary. An additional aspect of the calculation is the roofing material used.

The dependence of the pitch of the rafters on the roofing material

In addition to snow and wind loads related to variables, a constant (static) also acts on the roof, the force of which depends on the roofing material used. It is no secret that various types of roofs have their own mass, which can differ by 10 or more times.

The right choice of material affects not only the upper, but also all other parts of the construction of a residential building and other buildings. Not without reason, when designing the foundation, it is necessary to determine the choice of roof in advance.

Roofing

Currently, one of the most common roofing materials is a profiled sheet, produced in galvanized or followed by a polymer coating. The distinguishing features of the profiled sheet include the following parameters:

1. High corrosion resistance;
2. As a result, a long (over 15 years) life;
3. Easy installation even without the necessary qualifications;
4. Low sheet weight (weight 1 m 2 is 4-5 kg).

Since this roofing material does not exert a high load on the rafter system, the distance between the elements is selected as high as possible for a particular angle of inclination. In addition, the profiled sheet does not require high strength characteristics from the roof lathing. All this together allows you to minimize the total load on the foundation and walls.

Roofing

The second common type of steel roofing material is metal. This type of profiled sheet, successfully imitating natural clay material, but with a lower mass (10 or more). A feature of rafters for metal tiles is a smaller section size.

Choosing at what distance to install the rafters, you should first be guided by the dynamic load. Like the professional sheet, the metal tile is not demanding on the size of the rafter legs and is well mounted on the crate from an inch board of coniferous species. All this makes a metal roof low-cost.

Rafter system for ondulin

In the 21st century, wavy sheet materials were replaced by a more durable and lightweight analogue - ondulin. Among others - the most lightweight material. The mass of the sheet does not exceed 6 kg.

The small thickness of the ondulin sheets at slope angles of less than 15 ° requires the arrangement of a continuous crate of plywood sheets, for example, which will require an appropriate rafter step. This should be noted when calculating.

Slate roof

Not so long ago, wavy material from an asbestos-cement mixture called slate was widespread. High mass and fragility are the main disadvantages, however, to this day he finds his fans in the construction of various outbuildings.

A high mass, comparable with the weight of clay tiles, will not allow the same rafter system to be used as under a metal tile. Building standards determined the minimum angle of the slope of the roof from slate to 22 about or more. Otherwise, the load from the material itself and the rafter system with the crate exceeds the permissible parameters. The pitch of the inclined bars, as well as their cross section, are selected individually in each case.

Polycarbonate on the roof

In recent years, more and more often, on the roofs of porches and arbors, an artificial polymer material - polycarbonate - has been used. Available in two versions - monolithic and cellular. The first in its properties is similar to ordinary quartz glass, but significantly exceeds it in strength. The second has less mechanical properties, but high thermal insulation and light transmission.

Cellular polycarbonate is standardly much lighter than a monolithic fellow. It is used as a roof without the use of a battens, provided that the step does not exceed ½ of the width of the sheet of material. The high strength of the monolithic analogue also allows you to avoid transverse rafters of the elements. Sufficient flexibility allows you to cover semicircular roofs on a metal frame, the step of which does not exceed 0.9 meters.

Thematic Material:

Rafters under the soft roof

The original pattern can be obtained through the use of soft roofing materials creeping with an adhesive layer. Which are installed on a continuous crate of plywood or OSB. The rafter pitch should allow the sheets to be fixed, so it is chosen as a multiple of ½ of the width. Given the standard plywood dimensions of 1520x1520 mm, the center distance between the rafters will be: 1520: 3 \u003d 506 mm.

Step rafters for insulation

Installation of residential under-roof spaces is often combined with the laying of insulation sheets in the rafter gap. The most common are slabs with dimensions of 600x1000mm. We use these parameters as starting points.

The scheme of calculating the step of the rafters

According to construction standards, the pitch of the roof rafters is in the range of 0.6 - 1 meter. Its final calculation is performed according to a simple formula, depending on the total length of the roof. To calculate, you must perform the following list of actions:

1. determine what distance should be between rafters for your specific construction conditions. The directory determines the magnitude of wind and snow loads in the area.
2. the length of the roof is divided by the desired distance, adding one. The result will be equal to the number of rafter legs that are installed on one roof slope. In the event that the value is not an integer, it is rounded.
3. the length of the roof is divided by the number of rafters calculated above, we get the final step in meters.

For example, with a slope of 30 degrees, the maximum distance between the rafters of a gable roof under a metal tile is 0.6 measure. The length is assumed to be 16 meters. Consequently:

1. 16:0,6+1=27,66;
2. rounding the result, we get 28 rafters per slope;
3. 16: 28 \u003d 0.57 meters - the center distance of the rafter legs for these specific conditions.

As you can see, the calculation technology is not complicated, but this is only an approximate scheme. Taking into account many other parameters mentioned above can make certain adjustments.

The roofs of modern private houses can have different configurations. The most popular type of roof is gable. The unconditional advantages of such a roof, the owners of suburban areas consider reliability, a pretty attractive appearance and cost-effectiveness. The design of the roof of this type is extremely simple, and therefore to erect it will not be difficult, including with your own hands.

Light and durable sheet materials - this is what the gable roof is most often sheathed. Decking, for example, for such a design is just perfect. The roof of this variety protects the interior of the house well, lasts a long time and is inexpensive. Of course, the procedure for erecting the rafter system under the corrugated board, as well as under any other material, has some of its own characteristics.

Where to begin

How is the gable roof going? under the corrugated board it will turn out reliable, and the roof itself will be neat only if a detailed design project has been previously drawn up. When developing the latter, you need:

determine the angle of inclination of the slopes;

determine the type of materials necessary for the construction;

make detailed drawings of the frame indicating the method of connecting all nodes.

If all these operations are performed without errors, you will end up with a solid gable roof. The rafter system for corrugated board, the drawing of which can be done using, for example, special software on a computer, will last as long as possible.

Load calculation

This step in the design of the roof can not be skipped in any case. Correctly performed calculations are the key to the end result in a durable gable roof. The rafter system for corrugated board (photo of the assembly of such a frame can be seen below) is mounted taking into account the following parameters:

the weights of all used for materials;

The values \u200b\u200bof the last two indicators can be found in special tables developed specifically for each specific region.

All the numbers obtained as a result of the calculations must be added and multiplied by a reliability coefficient of 1.1. Having performed the calculation of the gable roof truss system in this way, it will be possible to determine first of all the type of materials necessary for the assembly. Also, taking into account the final load indicator, the optimal angle of the roof frame supports is chosen.

Slope angle

In addition to the load, the choice of this indicator should also take into account the features of the roofing material itself. The angle of inclination of the slopes can be any, but not less than 12 degrees. If you make the roof more gentle, then it will leak. In this case, the sheets themselves will begin to bend under the weight of snow in the winter. That is, the roof will have to be constantly repaired. And this, of course, is an additional cost.

In Central Russia, taking into account the wind and snow loads, it is almost everywhere possible to erect roofs with a slope angle of 30-45 degrees. This option is ideal for corrugated board. In the southern regions, the angle of inclination of the slopes of the roofs of houses can be smaller, and in the northern regions, on the contrary, it can be large.

Among other things, when choosing a method of installing rafters, it is worth considering the way in which the attic will be used in the future. If it is supposed to be insulated and equipped for a living room, it is better to make steep slopes. But of course, in this case, the construction of the roof will cost a little more, since you will have to use more materials.

What to build from

What concrete materials can such a gable roof be built from? with your own hands which, in any case, is a responsible matter, should, of course, be as reliable as possible. But one of the advantages of corrugated board is that it has a small weight. Therefore, it is not necessary to use any special, very durable materials for assembling the frame for it. For rafters of such a roof, a standard beam of 150x100 mm is quite suitable. Lumber of a larger section is advisable to use only if the attic is supposed to be used as a living room. Rafters for such a roof are usually made of 200x100 mm timber.

The crate can be assembled from a trim board 30x100-150 mm. Lumber too wide cannot be used in this case. After some time, such boards will simply dry out and become very distorted, which will negatively affect the reliability of the roof. Under the Mauerlat, it is better to take a thicker beam - 200x150 mm.

Step between structural elements

Too often, frame supports for light metal sheets are also optional. The optimal distance between the rafters of the gable roof under the corrugated board is 60-80 cm. As for the battens, the step between its elements is selected taking into account the variety of sheets used. So, for a thick material 0.6-0.7 mm with a profile height of 3.5 cm, boards can be stuffed at a distance of up to 1.5 m from each other.

For standard grade H sheeting, the lathing pitch is usually 60-70 cm. The same distance is suitable for CH material. Thin sheet C is mounted on a crate packed in 10 cm increments or on a 12 mm solid plywood or OSB sheets knocked down.

How the gable roof is going. Rafter system for corrugated board

The roof frame of the house is mounted in a few steps:

mauerlat is installed;

rafters are mounted;

if necessary, insulation is installed;

the rafters are tightened with a waterproof insulator;

the crate is stuffed.

Mauerlat installation

They begin to assemble such a structure as a gable roof made of corrugated board, with their own hands from the installation of this particular element. Mauerlat mounted on top of the box of the building. As a basis for the rafter system, this element is used only on brick, monolithic or block walls. In cobblestone and chopped, its role is played by the upper crown. Fasten the beam to the walls using anchor bolts. You can also use steel pins, galvanized wire with a thickness of 5 mm or staples.



Methods for attaching rafters

The supports themselves can be attached to the Mauerlat in two ways. For brick, block and monolithic houses, rigid fixing technology is used. In this case, they are attached to the Mauerlat using galvanized steel corners and self-tapping screws or a “knot” of three nails (one on the upper plane, two on the sides).

On the chopped and cobblestone walls, the rafters are mounted using the sliding method. The fact is that such houses in the first time after the construction give a strong shrinkage. Therefore, a rigidly fixed roof frame in the future can simply lead. When the sliding method of installing rafters is used, special fixing elements, "skids", providing support mobility in a small range.

How to install

You need to mount the supporting elements of the frame correctly. In this case, you get a neat symmetrical gable roof. The rafter system for corrugated board, as well as for any other material, must be assembled using a template. In this case, all legs will have the same length. For gable roofs from corrugated board, they can use either simple straight rafters (with the edge cut off at the necessary angle), and the option with landing nests for Mauerlat. Between themselves at the top of the frame support is usually fastened using special thick steel plates.

The first farms are always installed. Further, a cord is pulled between their highest points. Then, focusing on it, establish intermediate farms. On large roofs between the extreme paired rafters, a ridge run on supports is pre-mounted. The latter are securely fixed to the floor beams.

Installation of insulation and waterproofing

If the attic is supposed to be made residential, during the construction of the roof it will, of course, have to be insulated. Mineral wool is most often used on corrugated roofs for this purpose. As a support under it from the attic side, a wire is pulled onto the rafters. Mats themselves are set by surprise.

The waterproofing on the rafters is sewn with a slight sag (2 cm). It is impossible to stretch a film strongly. Otherwise, when the frame moves, it can simply break. Install the waterproofing strips horizontally from the bottom up with an overlap of at least 10-15 cm.



Installation of the lathing

Support boards under the sheets of corrugated board to the rafters are fastened with nails with a diameter of about 3-3.5 mm. The length of the fasteners should be twice the thickness of the fixed elements themselves. Assembly begins from the eaves. Boards should be fastened to each rafter with two nails. The last two rows of the ridge are filled without a gap.

After the crate is assembled, you can proceed to sheathing the frame with the corrugated board itself. At the final stage, the gables of the roof are studded with a board.

What you need to know

Wood - the material is very easy to process and at the same time quite durable. That is why the rafter system of a gable roof with their own hands is assembled most often from a timber and a board. However, unfortunately, the lumber cannot boast of too long a service life. Sooner or later, the roof frame of the building begins to crack or rot. Therefore, before its assembly, the timber and boards must be treated with special compounds that increase their moisture resistance.

Another disadvantage of wood is combustibility. In order to minimize the risk of fire, the lumber used to erect the building frame should, among other things, be carefully treated with a tool that increases their fire resistance.



Here in this way the gable roof is going. The rafter system under the corrugated board, as you see, is mounted elementarily. Nevertheless, the installation of a roof frame is a very responsible matter. In case of violation of any technologies, the owners of the house in the future will necessarily have problems with leaks, the need to replace individual elements, etc. Therefore, it is worthwhile to approach the assembly of the roof truss system with maximum responsibility.