Design gable roof for private houses it is chosen most often, since it is the best option for ease of installation and ease of use, for strength and reliability, as well as for a style solution. A gable roof is also called gable and has two slopes, which can be located in relation to each other under the same or different angles, that is, it can be an isosceles or a versatile triangle. The last option more and more often it can be found among new buildings, as it becomes 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 lathing fixed to the rafters has its own parameters for each of the coatings.

Gable roof: rafter system under which it has its own characteristics, must be carefully studied and calculated in advance, before buying 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, since you will have to choose the most suitable for a particular structure.

• Simple equilateral gable construction

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

Symmetry in this system helps to achieve a uniform load on the Mauerlat and load-bearing walls... At the right choice section of the bar for arranging the rafter system and the Mauerlat, these details will provide the necessary long-term operation roof safety margin. Correctly installed struts, struts and tightening will add additional reliability to the structure.

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

• Simple asymmetrical gable design

The asymmetrical gable design differs from traditional system the fact 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 ​​the attic space, in which it is quite possible to equip a living space, of course, with proper insulation.

Another important advantage of such a structure can be a smaller slope, which is recommended to be planned from the leeward side of the building, where it is always assembled on the roof a large number of snow. A small slope, but with a large steepness, will not hold large snowdrifts on its surface.

The disadvantage of an 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 rafter system can be called a rarity, although thanks to this arrangement of slopes in the attic space, enough large room, which can be used as a residential or utility room.

In addition to such a rafter system, a broken gable structure can be attributed to attic option installation of rafters.

Both ramps are "broken" - a clear win in useful area attic space

3 - A stand installed on a bed.

4 - rafter.

5 - Lathing.

The elevated system differs from the hanging system in that it is installed on a structure that has internal capital partitions. Capital interior walls are used to fix the bed on them, on which the racks are installed, supporting the ridge girder, with which the upper ends of the rafter legs are fastened. Then the sheathing boards are fixed on the rafters.

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

rafters

Hanging rafter system

The hanging rafter system diagram looks as shown in the illustration, and includes the following main elements:

1 - Bearing walls.

2 - Mauerlat.

3 - Rafters.

4 - Lathing.

5 - Tightening (crossbar).

The hanging rafter system is mounted on two external load-bearing walls, on which the Mauerlat is pre-fixed. This roof option can only be applied if the distance between the load-bearing walls is no more than 7000 mm, since apart from them additional support for truss structure there is no roof. Such a system is usually equipped with puffs supported by slopes - these elements will remove some of the load from the walls of the building.

In addition to overhead and hanging systems, there are combined options which include individual elements of both designs.

When the rafter system is selected, it is recommended, before purchasing materials, to draw up detailed drawing roofs with marked dimensions - this will make it easier to calculate the amount of everything you need 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, you will have to carry out some

How to calculate the parameters of a gable rafter system

Correctly calculate the parameters of the elements for installation works- very important. To do this, it is first recommended to make a list of everything you need and make the calculation step by step. All calculations should be made with a margin of 10 ÷ 15%, avoiding unnecessary savings, which will be to the detriment of the quality and strength of the structure.

If it is decided to do this part of the work independently, it is imperative to check with the technical documents developed by specialists, for example, posted in SNiP.

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

Loads 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 film, fasteners, finishing materials for the interior of the attic. The weight of all the elements and materials required for the roofing "pie" is summed up, and on average, an optimal value of 40-45 kg / m² should be obtained. It is advisable to calculate the materials so 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 structure. These include the following effects:

— weight of people with 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 effect 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 written off, but the windage of the roof increases significantly, and the wind becomes the dominant external influence.

Calculation data can be found in SNiP 2.01.07-85 * “Loads and Actions” in the “Snow Loads” and “Wind Loads” sections. In this case, 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 a hill, a detached structure or surrounded by other buildings.

A convenient algorithm for calculating loads will be given below.

• Special loads. This category includes factors such as seismic effects, hurricane winds, deformation processes due to soil subsidence, which are usually called force majeure. 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 is to be installed on an old building, it is necessary to calculate the bearing capacity of the foundation and walls, since the new roof may have a greater weight than the old one. Such calculations can only be professionally carried out by specialists, but it is imperative to make such calculations, otherwise you will not only have to change the roof, but also repair the entire structure. In this case, specialists will need to provide a roof project, which will indicate all its parameters.

The angle of inclination of the rafter system slopes 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 himself 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.

Increasing the slope angle will significantly expand the attic space, but it will take more to build such a roof building materials and, of course, the cost of construction will increase significantly.

So, any gable rafter system, it doesn't matter whether it is symmetrical or not, can be represented in the form of a triangle.

Its vertices:

- dot "but"- this is the outer point of intersection. Angle "A" is adjacent to this vertex, which determines the steepness of the roof slope.

- dot « b "- the top of the ridge.

- dot "with"- the intersection of the plumb line from the ridge with the overlap or simply the upper 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" for the formation of a cornice overhang.

According to the well-known trigonometric relations:

H =D × tgA

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

All this makes it easy to do the calculator below. Changing the value of the angle " BUT" you can come to the optimal height value " N ".

Before installing the rafter system, the question arises, with what step to put the floor beams. Correctly calculating the distance between the rafters means subsequently preventing deformation or even destruction of the roof frame. After reading the article to the end, readers will find out what the distance between the rafters should be for of various kinds roofs and how to make the correct calculation.

Even at the design stage of a wooden house, all load calculations must be made. This also applies to the rafter system. This is especially important in wooden housing construction, since the top link is often used instead of the Mauerlat. It is difficult to correct errors in such a design later. For correct calculation the distance between the beams is a technique.

The span of the roof frame for the construction of a house from a bar usually exceeds 1 m, and the smallest allowable value is 60 cm, such indicators are indicated in GOSTs (see figure). You can correctly calculate the length of the rafters, their step, as follows:

Using a tape measure, the length of the roof slope is measured, the result is divided by the step size of the roof frame. For example, if the distance between the rafters is 1 m, then you need to divide by 1, if 70 cm, then by 0.7. The resulting figure is added to 1 and rounded to the nearest higher number. This allows you to determine the number of beams for one roof slope.

You need to divide the length of the future slope by the result obtained. The result is the distance between each rafter.

For example, consider a roof, the slope of which is 25.5 m and a step of 0.6 m. You need to calculate the following indicators: 25.5: 0.6 = 42.5, to 42.5 + 1 = 43.5. We round this figure to the nearest higher integer, we get 44. This number roof beams for 1 slope of the future roof.

Now we calculate the span between the rafters: 25.5: 44 = 0.58 m.It turns out that you need to put the legs of the frame every 58 cm.This way you can easily calculate the pitch of any roof frame, single-pitched or complex, without taking into account the roof. But professionals recommend their calculations for a certain type of roof.

Rafter leg step depending on material

Since each forging material has its own characteristics and characteristics. Among the most common are:

1. Decking. It has a different thickness and shape of the tropeziform bend. Costs from 120 rubles.
2. Ceramic tiles. Expensive material from 670 rubles. Has 12 color options.
3. Metal tiles. It's over cheap stuff unlike ceramic and costs from 320 rubles.
4. Ondulin. The soft roof insulates the house from rain, hail, etc. Costs from 340 rubles.
5. Slate. Most economical option from 90 rubles

The step size for the most common types of coverage is discussed below.

Step of rafter beams for corrugated board

The distance between the roof beams depends on the size of the sheet that the corrugated board has. The pitch of the beams of the roof frame under the corrugated board is taken as standard not less than 60 cm and not more than 90 cm.

If this distance is greater, then boards with a large section are attached between the rafter beams. The cross-section of the rafter legs for the corrugated board is chosen 50x100 or 150 mm.

The most important thing to consider when going to fasten the corrugated board is the crate. They make it from a board with a section of 30x100mm, you need to mount it with a span of 50 cm. It depends on the brand and thickness of the corrugated board and the slope of the roof.

So a 15 ° roof, C 10 brand corrugated board is mounted on a solid crate, C 21 corrugated board is mounted on a crate with a span of 30 cm. The largest C 44 corrugated board is mounted on a crate with a pitch of 50 cm, up to 1 m. chimney passage, ventilation hood, etc.

Step of rafter beams for ceramic tiles

The specificity of the installation of the truss system for laying ceramic tiles is associated with the weight of this roof. Ceramic tiles are made of clay, and this roof has a weight 9-10 times more than that of a metal tile. Calculation of the load on the rafter system for ceramic tiles is 40-60 kg / m 2.

Beams for the roof truss system are made for ceramic tiles only from dried material. The section is suitable for 50x150 or 60x180 mm. The standard distance between the rafter legs when roofing tiles is 80-120 cm. The span depends on what slope the roof has. At an angle of 15 °, the span between the rafters is 80 cm, at 750 through 1 m 30 cm.

When calculating the step, you need to take into account the length of the beam. Taking the maximum length, the distance between the rafters is minimal. And, on the contrary, with the minimum length of the rafters, the step is maximum.

When laying ceramic tiles, it is important to take into account that you will need to move along the roof. The safest step of the rafter legs for such a movement is 80 cm.

It is important when laying ceramic tiles to calculate the span of the sheathing. This distance is directly related to the size of the roofing material. A standard shingle sheet is 40 cm long. It is laid with an overlap of 50 to 90 mm. Calculating the step of the battens, the size of the overlap is subtracted from the length of the tiles. The result is a step of 305-345 mm.

For shed roof it is not difficult to make a calculation for the construction of a house from a profiled bar. If the roof is of a complex multi-pitched shape, then each distance between the rafters is calculated separately for the sheathing step. By fixing the cord on the opposite side of the roof slope, you can easily mark the rows.

Features of the roof frame for metal tiles

Metal tiles are used more often than ceramic or corrugated board. Externally, the roof resembles ceramic tiles, but unlike it, it is easier to install and lighter.

The metal tile weighs from 35 kg / m 2 of the roof. This makes it possible to lighten the structure of the rafters and use beams with a smaller section. The step between the rafter legs of the roof frame increases and is equal to 60 to 90 cm. The beam is used with a section of 50x150 mm.

To create a ventilated space in the beams under the roof, holes with a diameter of 12-13 mm are drilled.

The design of the roof frame for metal tiles is not much different from corrugated board or ceramic tiles. But there is a small feature: the support from above is attached to the ridge girder from above, and not from the side as in other cases. So under metal tiles a ventilated gap will appear, which will exclude the accumulation of condensate.

Features of rafter legs for ondulin

Ondulin is soft roof used for the construction of a house from laminated veneer lumber or other material. Ondulin is produced in the form of sheets; it looks like painted slate, but lightweight. This material is great for wooden houses both low-rise and large.

The rafter beams under the ondulin are placed with a distance of at least 60 cm, a maximum of 90 cm.For the rafter system, use a bar made of conifers wood with a section of 50x150 or 50x200 mm. A smaller section will not provide sufficient strength to the rafter girders.

The lathing on the rafters is made of a material with a cross section of 40x50 mm with a step of 60 cm.This is quite enough for fastening ondulin sheets with an overlap of 30 cm. Ondulin is fastened with special nails that are sold in the kit.

Features of the rafter system for slate

Slate is rarely used for roofing modern houses... But in suburban construction and households. buildings, this material is irreplaceable. He has low cost and easy to assemble.

Slate rafters

Rafter legs for slate are used with a section of 50x100 or 50x150 mm. The fastening step between the rafters is not less than 60 cm and not more than 80 cm.

The slate crate is made of 50x50 mm bars or wide board 30x100 mm. The lathing is laid from the steps, depending on the roof slope. For a steep pitched roof, it is 45 cm. Consumption is 4 bars per 1 sheet of slate. For a flat slope or gable roof 63-65 cm, so the consumption is reduced to 4 bars per sheet.

The step of the rafter system under the slate differs by the roof structure. For households. buildings are often mounted shed.

Dimensional feature between the rafter beams at a pitched and a gable roof

Whether a safety margin is needed during installation depends on what shape the roof is. And the distance between the rafter beams directly depends on this.

Single slope rafter system

A pitched roof is more durable and easier to assemble. The thickness of the rafters is selected depending on the type of wood, its strength and the specificity of a particular structure. The step between them can be 60-140 cm. The distance also takes into account whether the structure will be insulated. If so, then the step should correspond to the width of the insulation.

The thickness of the rafter beams must be calculated depending on the roof slope. For a slight slope of 15-20º, you can use a material with a section of 50x100 mm. For a steep slope of 45º, a more durable section of 50x150 mm is needed.

Gable rafter system

If the calculation of the step of the legs of the frame of a pitched or other type of roof is not correct, then the roof can be taken away, and the beams will sag and bend from the weight of the structure. In this case simple repairs not enough, you will have to redo the entire structure. Therefore, it is so important to correctly calculate the distance between the legs of the rafters, depending on the roofing material used: corrugated board, ceramic or metal tiles, ondulin or slate, etc.

Another name for the gable roof variety is gable.

It has two identical sloped surfaces. The roof frame structure is represented by a rafter system.

At the same time, pairs of rafters leaning against each other are united by a crate. At the ends, triangular walls are formed, or in another way, tongs.

A gable roof is easy enough .

At the same time, very important point for installation is the correct calculation of the required parameters.

The attic truss system contains the following elements:

• Mauerlat. This element serves as the basis for the entire roof structure, is attached along the perimeter of the walls from above.
• Rafters. Boards of a certain size, which are attached at the required angle and have a support in the Mauerlat.
• Skate. These are the designations for the convergence of the rafters at the top.
• Rigeli. They are located horizontally between the rafters. Serve as an element of adhesion of the structure.
• Racks. Supports that are placed vertically under the ridge. With their help, the load is transferred to the load-bearing walls.
• The brace. Elements at an angle to the rafters to take the load off.
• Sill. It is similar to the Mauerlat, only it is located on the internal load-bearing floor.
• Fight. A bar located vertically between the supports.
• . Roof installation structure.

Calculation of the rafter system of a gable roof - online calculator

Calculator Field Labels

Please indicate the roofing material:

Select material from the list - Slate (wavy asbestos-cement sheets): Medium profile (11 kg / m2) Slate (corrugated asbestos-cement sheets): Reinforced profile (13 kg / m2) Corrugated cellulose-bitumen sheets (6 kg / m2) Bituminous (soft, flexible) shingles (15 kg / m2) From galvanized sheet (6.5 kg / m2) Sheet steel (8 kg / m2) Ceramic tile (50 kg / m2) Cement-sand tile (70 kg / m2) Metal tile, corrugated board (5 kg / m2) Keramoplast (5.5 kg / m2) Seam roofing (6 kg / m2) Polymer-sand tile (25 kg / m2) Ondulin (euro slate) (4 kg / m2) Composite tile (7 kg / m2) Natural slate (40 kg / m2) Specify weight 1 square meter of coverage (? Kg / m2)

kg / m 2

Enter the parameters of the roof (photo above):

Base width A (cm)

Base length D (cm)

Lift height B (cm)

Side overhang length C (cm)

Front and rear overhang length E (cm)

Rafters:

Rafter pitch (cm)

Wood grade for rafters (cm)

Side rafter working area (optional) (cm)

Crate calculation:

Sheathing board width (cm)

Sheathing board thickness (cm)

The distance between the boards of the crate
F (cm)

Calculation snow load(pictured below):

Select your region

1 (80/56 kg / m2) 2 (120/84 kg / m2) 3 (180/126 kg / m2) 4 (240/168 kg / m2) 5 (320/224 kg / m2) 6 ​​(400/280 kg / m2) 7 (480/336 kg / m2) 8 (560/392 kg / m2)

Wind load calculation:

Ia I II III IV V VI VII

Height to the ridge of the building

5 m 5 m to 10 m 10 m

Terrain type

Open area Closed area Urban areas

Calculation results

Roof angle: 0 degrees.

The tilt angle is suitable for of this material.

It is advisable to increase the angle of inclination for this material!

It is desirable to reduce the angle of inclination for this material!

Roof surface area: 0 m 2.

Approximate weight of roofing material: 0 kg.

Number of rolls insulating material with 10% overlap (1x15 m): 0 rolls.

Rafters:

Load on the rafter system: 0 kg / m 2.

Rafters length: 0 cm.

Number of rafters: 0 pcs.

Lathing:

Number of rows of battens (for the entire roof): 0 rows.

Uniform distance between battens: 0 cm.

The number of battens with a standard length of 6 meters: 0 pcs.

The volume of the crate boards: 0 m 3.

Approximate weight of crate boards: 0 kg.

Snow load region

Calculator fields description

It is quite simple to make all the calculations before starting work on the construction of the roof. The only thing that what is required is scrupulousness and attentiveness, you should also remember to check the data after the process is complete.

One of the parameters, which cannot be avoided in the calculation process total roof area. It should be initially understood what this indicator represents, for a better understanding of the entire calculation process.

There are some general provisions that are recommended to be followed in the calculation process:

1. The first step is to determine the length of each of the slopes. This value is equal to the intermediate distance between the points at the very top (on the ridge) and the lowest (cornice).
2. Calculating such a parameter all additional roofing elements, for example, overhangs and any kind of structures that add volume.
3. At this stage also the material must be defined, from which the roof will be constructed.
4. Do not need to be considered when calculating the area, ventilation and chimney elements.

ATTENTION!

The above points are applicable in the case of a conventional roof that has two slopes, but if the house plan assumes the presence of an attic or another type of roof shape, then the calculations are recommended to be carried out only with the help of a specialist.

Best of all, a gable roof rafter system calculator will help you in calculations.

Calculation of the rafter system of a gable roof: calculator

Calculation of rafter parameters

In this case, you need to start from a step, which is selected individually taking into account the roof structure. This parameter is influenced by the selected roofing material and the total weight of the roof.

This indicator can vary from 60 to 100 cm.

To calculate the number of rafters you need:

• Find out the length of the slope;
• Divide by the selected step parameter;
• Add 1 to the result;
• For the second slope, multiply the exponent by two.

The next parameter to determine is the length of the rafters. To do this, you need to recall the Pythagorean theorem, this calculation is carried out on it. The formula requires the following data:

• Roof height. This value is chosen by everyone individually, depending on the need to equip the living space under the roof. For example, this value will be equal to 2 m.
• The next value is half the width of the house, in this case - 3m.
• The quantity you need to know is the hypotenuse of the triangle. Having calculated this parameter, starting from the data for the example, it turns out 3, 6 m.

Important: to the result obtained, the length of the rafters should be added 50-70 cm with the expectation of a gash.

Besides, it is necessary to determine what width to choose the rafters for installation.

You can make rafters with your own hands, you can read how to do this.

For such a parameter, you need to consider:

Determination of the angle of inclination

It is possible for such a calculation proceed from roofing material, which will be used in the future, because each of the materials has its own requirements:

• For the size of the slope angle must be more than 22 degrees. If the angle is less, then this promises the ingress of water into the gaps;
• For this parameter should exceed 14 degrees, otherwise, sheets of material may be torn off in a fan;
• For the angle may not be less than 12 degrees;
• For bituminous shingles this indicator should be no more than 15 degrees. If the angle exceeds such an indicator, then there is a possibility of material slipping from the roof during hot weather, because the attachment of the material is carried out on the mastic;
• For roll-to-roll materials, the angle can be varied from 3 to 25 degrees. This indicator depends on the number of layers of material. Large quantity layers allows you to make the slope of the slope large.

It should be understood that the larger the slope angle, the more free space under the roof, however, more material is required for such a structure, and, accordingly, costs.

You can read more about the optimal tilt angle.

Important: the minimum allowable slope angle is 5 degrees.

The formula for calculating the angle of the slope is simple and obvious, given that initially there are parameters for the width of the house and the height of the ridge. Having presented a triangle in a section, you can substitute data and carry out calculations using Bradis tables or an engineering-type calculator.

You need to calculate the tangent acute angle in a triangle. In this case, it will be equal to 34 degrees.

Formula: tan β = Нк / (Losn / 2) = 2/3 = 0.667

Determining the angle of inclination of the roof

Calculation of loads on the rafter system

Before proceeding with this section of calculations, you need to consider all kinds of loads on the rafters. , which also affects the load. Types of loads:

Load types:

1. Constant. This type of load is constantly felt by the rafters, it is provided by the roof structure, material, lathing, films and other small elements of the system. average value this parameter is equal to 40-45 kg / m 2.
2. Variable. This type of load depends on the climate and the area of ​​the structure, since it is precipitation in this region.
3. Special. This parameter is relevant if the location of the house is a seismically active zone. But in most cases, the added strength is sufficient.

Important: best of all when calculating strength, make a margin, for this, 10% is added to the resulting value. It is also worth taking into account the recommendation that 1 m 2 should not take on weight, more than 50 kg.

It is also very important to take into account the load exerted by the wind. Indicators of this value can be taken from SNiP in the "Loads and Impacts" section.

• Find out the parameter of the weight of the snow. Basically, this indicator varies from 80 to 320 kg / m 2.;
• Multiply by the factor that is required for accounting wind pressure and aerodynamic properties. This value is indicated in the SNiP table and is applied individually. Source SNiP 2.01.07-85.
(in this example) that will need to be purchased for construction.

To do this, it is necessary to divide the resulting value of the roof area by the area of ​​one sheet of metal tile.

• The length of the roof in this example is 10m. To find out such a parameter, you need to measure the length of the skate;
• The length of the rafter has been calculated and is equal to 3.6m (+ 0.5-0.7m.);
• Based on this, the area of ​​one slope will be equal to - 41 m 2. Total value area - 82 m 2, i.e. area of ​​one slope multiplied by 2.

Important: do not forget about the allowances for the roof peaks of 0.5-0.7 m.



Roofing set

Conclusion

All calculations are best checked several times to avoid errors. When this painstaking preparatory process will be completed, you can safely proceed to the purchase of material and prepare it in accordance with the received dimensions.

After that, the process of installing the roof will be simple and quick. And in the calculations, our gable roof calculator will help you.

Useful video

Video instructions for using the calculator:

In contact with

Construction of the roof of the building - important stage in the construction of a house, while it is necessary to calculate the step of the rafters as accurately as possible, since the reliability and service life of the roof will depend on this.

If the master does not pay attention to the calculations and installs the rafters, focusing only on his own eye, then the frame will turn out to be either too heavy, moreover expensive, or fragile.

General calculation rules

The step of the rafters is the distance from one to the other rafter leg. It is believed that such a distance is set in the range from 60 cm to 100 - 120 cm (determined with optimal width, you need to take into account the dimensions waterproofing materials and insulation).

The exact pitch of installing rafters for a gable roof can be calculated according to the following diagram:

• we measure the length of the slope along the eaves of the roof;
• we divide the measurement data by a certain step (we determined the step of 1 m - we divide by 1, if the step is 0.8 m - we divide by 0.8, etc.);
• add 1 to the resulting number;
• we round the total (upwards) - we see the number of rafters for installation on one slope of a gable roof;
• the length of the ramp is divided by the resulting number and we get the exact step between the rafters.

For example, the length of the roof slope is 30.5 meters, taking into account the width of the rolls of insulation and waterproofing, a step of 1 meter is chosen.

30.5 m / 1 m = 30.5 + 1 = 31.5. Rounding up gives a result of 32. 32 rafters are required per roof frame.

30.5 m / 32 pcs. = 0.95 cm - the value of the distance (step) between the centers of the rafters.


However, this formula does not take into account the nuances of certain roofing materials, therefore, in the future, the article will consider how to calculate the correct pitch of the rafters for the most demanded coatings.

It is especially worth highlighting the rafter system when erecting a hip roof (envelope). The construction of such a roof begins to be built precisely from the hip legs, into which the rest of the rafters are then cut.

A hip that is over 6 m in length is often reinforced by stitching it in two pieces. Otherwise, the installation and calculation of the pitch of the rafters for a hip roof are similar to the installation and calculation of a gable roof.

System of rafters for ceramic and metal tiles

The use of metal tiles in the construction of private houses is the most common phenomenon, which is facilitated by whole line its positive qualities.

Firstly, it is the low weight of the coating, which facilitates installation and helps to reduce the load on the supporting structures.

Secondly, large roof areas can be quickly covered with sheets of metal tiles, which is very convenient, especially if you choose a gable roof option.

The pitch of the rafters under the metal tile is set in the range from 60 to 95 cm, since the relatively low weight of the roof does not require increased resistance. Due to the low weight of the coating, the thickness of the rafters can also be reduced.



As for the thickness thermal insulation material used for insulating roofs made of metal tiles, experts believe that when installing an attic under it, for greater confidence in reliability, thermal insulation of 20 cm can be used, in other cases 15 cm is enough.

A feature of roofs covered with metal tiles is the possibility of condensation accumulation.

This can be avoided by organizing ventilation during the installation of the rafters: for this, at a short distance from the top in the rafters, you need to drill several holes (about 10 mm in diameter).

As for the installation of a rafter frame under a coating such as natural (ceramic) tiles, you must remember about its high weight.

In comparison with other modern materials, tiles are 10 or more times heavier. Given this feature, experts recommend using exclusively dry wood under it in order to avoid sagging after drying.

For rafters, in this case, you need to use a bar with a section of 50 - 60 mm * 150 - 180 mm; the width of the step of the rafter legs is set in the range of 80 - 130 cm, while the greater the degree of the roof slope, the greater the distance between the axes of the rafters.

The step of the rafters is also dependent on their length: the greatest length will require the smallest distance, and vice versa. IN otherwise the roof frame will lose the necessary stability.

Taking into account the size of the tiles (as a rule, its length does not exceed 40 cm), it is necessary to correctly calculate the width of the step of the sheathing stuffed on the rafters.

From the length of the slope, you need to subtract the length of the bottom row and the number of centimeters between the crate and the last bar.

Frame for ondulin, corrugated board and soft roof

Such types of roofs as corrugated board and ondulin are relatively new on the market of materials. At the same time, they are successfully used both for gable and hip roofs.

The weight of these materials is practically equal to the weight of the metal tile, therefore the calculation of the step width of the rafters will be similar to the calculation when laying metal sheets... The step of the rafters under the corrugated board is determined from the range of 60 - 90 cm, under the ondulin - 60 - 100 cm.

The sufficient thickness of the rafters themselves when covering the roof with ondulin and corrugated board is 50 * 200 mm.

If it is necessary to increase the distance between the centers of the rafters, then the strength of the transverse lathing can be increased.

The rule for installing the lathing under the corrugated board is similar to installing the lathing under the metal tile: the last board must be taken wider than the others (as a rule, 15 cm thicker).

The lathing for ondulin must be made continuous to increase the resistance of the material to various weather conditions.

Speaking about the device of the truss system for a soft roof, it is worth remembering the types of such material presented on the markets: this is a roll type of roof and bituminous tiles.

The name itself suggests that for a soft roof it is necessary very solid foundation to withstand heavy snow cover, gusts of wind and torrential rains.

The main requirements for roof frames for soft roofs are that they must be strong and even.

The strength should be calculated for the thickness of the snow characteristic of the region in which the structure is being erected, and for average weight an adult male to be able to troubleshoot.

A flat roof should be for the reason that it excludes the possibility of sagging under the influence of the above-described weather phenomena.



Between the axes of the rafters for a roof frame with a soft roof, the step should be small, no more than 50 cm.

If the step is still larger, you will need to make a rough crate, on which the main one will be mounted, solid.

The counter lattice will help the soft roof not to bend and will increase its service life by an order of magnitude. For solid lathing, a 30 mm board is more often used, or OSB plate 20 mm.

If a soft roof is provided as a covering for a hip roof with the organization of an attic space, then it is necessary to think about its insulation, having thought over a filing for laying insulation, hydro and vapor barrier.

These are all the subtleties of the roof frame device for a soft roof.

Slate roof rafters

Despite wealth and diversity modern materials, good old slate remains quite popular. The use of expensive roofing coatings is far from always justified, and this is when an asbestos-cement sheet comes to the rescue.

The weight of the slate is quite impressive, while its installation does not require any grandiose lathing. This is because such a roof itself is strong enough.

For the construction roof frame in this case, rafters with a section of 150 * 40 mm and a bar with a section of 35 * 35 mm for the lathing are required.

Lumber for the construction of the frame should be stacked and kept for some time to give the same level of moisture.



After completing the drying process, it is necessary to determine the bend. The rafter legs are recommended to be installed with the concave part (tray) upwards - so the water, if it hits the rafters, will slide down, bypassing the attic space.

Before starting the installation, the beams are checked for knots in them and rejected, since the knotty material may not withstand the severity of the roof.

In this case, rafter fasteners are made with nails, the optimal length of which is 15 - 20 cm.

Nails should pierce the beam through, but the protruding ends should never be bent, since it is required to maintain the mobility of the structure.

When the wood dries out and deforms, this technique will prevent cracking of the slate sheets.

The lathing for the device of a slate roof can be solid or sparse. Solid is made from a sheet of OSB or plywood and is more often used when laying flat slate.

Sparse is typical for stacking on it wave slate... For a sheet with standard size 1.75 m the pitch of the lathing is about 80 cm. It makes no sense to make the lathing more frequent, since the slate has a sufficient margin of safety.

After analyzing the materials of the article, you can independently start erecting the frame of a gable and hip roof, having determined for yourself their features and properties of roofing materials.

It will not be superfluous to remind that the calculation of the rafter step is a very responsible occupation, and it is necessary to approach it responsibly, as this will avoid mistakes and speed up the progress of work in the future.

When carrying out installation work, it is very important to correctly determine the step of the rafters for the metal tile. It is important to understand that it is quite difficult to make such calculations and it is on how correctly everything is done that the level of roof strength directly depends. Many experts argue that the operational life of not only the roof, but also the structure itself depends on the level of reliability of fastening the metal tile to the rafters. As a result of the fact that the metal tile has a rather large weight, the rafter system must be strong. In addition, beginners will not be able to lay roofing material. In order to properly carry out the installation work, it is recommended to take a responsible approach to calculating the step of the rafter system.

The device of the rafter system for metal tiles

Do-it-yourself rafter system for metal roofing is not as difficult as making the appropriate calculations. It is important to understand that the type of system used depends entirely on the type of roof. Today, the most popular option is the rafter system for a gable roof for metal tiles. Such rafter systems, as practice shows, are excellent for installing metal tiles on the roof of a dwelling. To equip the rafters use wooden blocks different lengths- the choice, as a rule, directly depends on the length of the legs. Many experts recommend paying attention to the fact that it is necessary to choose the correct angle of inclination, which can vary from 15 to 30 degrees - this value is considered optimal.

Calculation of the distance between rafters for metal tiles

The step of the rafters under the metal tile is the distance from one rafter leg to the other, if you put it differently, the roofers call this distance the step of the rafter system. This distance directly depends on the selected type of roofing. As practice shows, for all roofing materials, including metal tiles, this size varies from 0.6 to 1.2 m.However, it is important to understand what is best to carry out accurate calculations distances for each material separately - there must be an individual approach.

Before proceeding with the installation work, it is necessary not only to determine the distance between the rafters, but also to understand how much material is required for the legs. To find out the step of the rafters of a gable roof under a metal tile or a pitched roof, it is recommended to adhere to the following recommendations:

1. The first step is to calculate the length of the roof slope from the metal tile. Measurements, as a rule, are carried out along the eaves of the roof.
2. After that, it is possible to select an arbitrary step. It is important to take into account the fact that the step limits for metal tiles can vary from 0.6 to 1 m. For example, initially it became necessary to adhere to a distance of 0.8 m. The length of the ramp should be divided by the selected value for the step of the rafter system. Suppose that the length of the slope is 12 m, it turns out that 12 / 0.8 and it turns out 15. After that, you need to add 1 to the resulting value. In the case when the number is fractional, then it should definitely be rounded up. Thus, it turns out 15 + 1 = 16. This value shows how many rafter legs should be installed on the roof. Then you need to take the length of the slope and divide it by the resulting number of legs. It turns out that 12/16 and it turns out 0.75 m.

Many experts recommend entrusting these works to professionals, which will allow you to get the desired result in the future. It is important to understand that there is a high probability that mistakes will be made, which will ultimately negatively affect finished structure roofs.

Attention! As practice shows, such calculations can be used for any roofing materials.

Installation of rafters under metal tiles

Since the installation work is carried out at a high altitude, if necessary, you can assemble the frame for the supporting rafter system on the ground, and then lift and fix it on the roof. For these purposes, it is best to create a special template or a diagram of the rafter system for metal tiles from boards, according to which the installation will be carried out.

The whole process is carried out in stages:

1. First of all, the boards are raised above the wall of the building, leveled and fixed with nails.
   
   
2. According to the project, the boards should be aligned at a certain angle of inclination, after which all elements are securely fixed.
   
   
3. Ultimately, a design should be obtained that, according to appearance and the shape resembles a rafter system. Manufacturing must be carried out taking into account the calculations made.
   
   
4. Then you need to lower the template to the ground and install all the finishing elements.

You should also not forget about the installation of supporting elements, namely the Mauerlat. Laying is carried out on load-bearing walls in a longitudinal position. Special pins or wire rods are used as fasteners.



The next step is installation ridge run, which is used as a support for all roofing. For work, you will need to use a bar or a hewn log. In cases where the length of the slope does not exceed 6 m, then additional support elements can be dispensed with.



When the installation of all the elements has come to an end, you can proceed with the installation and further installation work on arranging the rafter system according to the attached template.

Mauerlat can be fixed in several ways:

• rigid connection- in this case, a bar or corners should be used, nails and staples are used much less often, a feature is the fact that it will be necessary to additionally tie the rafters to the wall, using anchors for these purposes;
• sliding way- in such cases, a hinge connection must be created, it can be done due to the joining of elements with cuts.

During work, the step distance of the rafter system must be observed.

When choosing a rafter pitch for metal tiles, you should pay attention that the distance should not be less than the minimum allowable value and more than the maximum allowable value, that is, it can vary from 0.6 m to 1.2 m.

If it was decided to choose a distance from 0.6 to 1 m, then the length of the rafters in this case should not be more than 6 m.In the event that it is reduced, it is allowed to make a breakdown of up to 1.2 m.

If the legs of the rafter system are installed more often than 0.6 m, then this will only contribute to a significant weighting of the roof and, as a rule, to an increase in costs. If necessary, the distance can be 1.2 m, but it is important to understand that in this case the level bearing capacity will be significantly reduced, which will negatively affect the construction of metal tiles.

If necessary, you can increase the level of strength, then this will require a continuous crate of wood-based panels... In such situations, the pitch can vary from 0.2 to 0.3 m. This option it is used extremely rarely, since its implementation requires much more investment.

An interval of 1.2 m is almost never used during installation work. This is due to the fact that despite the rather high level strength, the metal tile will begin to sag under the weight of snow in winter period time or with strong gusts of wind.

An important value is the cross-section of the timber used for arranging the rafter system. It depends on him what distance will be chosen. The best option the choice of wooden bars with a cross section of 150 * 150 mm is considered, while the lathing can be installed with an interval of 4 to 7 cm. In this case, it is recommended to take into account the step of the shear wave.



Conclusion

The step of the rafters under the metal tile can be determined only after the corresponding calculations have been carried out. It is important to understand that if the distance is rather small, this can significantly increase the consumption of material and the budget of the project, and if the distance is made too large, then during operation the roofing material will begin to sag, which will lead to deformation of the metal tile.