The insulation of the duplex roof is a big pitch. Step rafted a bone roof. Scroll system for Ondulin

The construction of the roof of the structure is an important stage in the construction of the house, while it is necessary to calculate the step of the rafter as accurately as possible, since it is precisely that the reliability and service life of the roof will depend on this.

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

General rules for calculation

A step of the rafter is called the distance from one to another rafting leg. It is believed that such a distance is set in the range from 60 cm to 100 - 120 cm (aligned with the optimal width, it is necessary to take into account the size of waterproofing materials and insulation).

The exact setting step of the rafter for a bone roof can be calculated according to the following scheme:

• we measure the length of the skate on the roof eaves;
• we divide the data of the measurement to a certain step (determined step 1 m - divide by 1, if step 0.8 m - divide by 0.8, etc.);
• to the resulting number add 1;
• the result is rounded (in the direction of increasing) - we see the number of rafters to install on one slope of the liquid roof;
• the length of the skate is divided on the resulting number and get an accurate step between the rafters.

For example, the length of the roof skate is 30.5 meters, given the width of the heaters and waterproofing rolls, the size of 1 meter is selected.

30.5 m / 1 m \u003d 30.5 + 1 \u003d 31.5. Rounding in a large direction gives the result 32. The frame for the roof rope will take 32 rafters.

30.5 m / 32 pcs. \u003d 0.95 cm - the distance (step) between the rafted centers.

However, this formula does not take into account the nuances of certain roofing materials, so later in the article will be considered how to make the calculation of the right step of the rafted under the most popular coverage.

Especially it is necessary to highlight the system of rafters when the hip roof is erected (envelope). The design of such a roof is starting to construct precisely from the holm feet, which then cut the rest of the rafters.

Walma having a length of above 6 m is often amplified by crosslinking it from two elements. Otherwise, the installation and calculation of the step of the rafter for the holm roof is similar to the installation and calculation of the bounce.

System rafted under ceramic and metal tile

The use of metal tile in the construction of private sector houses is the most common phenomenon, which contributes to a number of its positive qualities.

First, it is a small weight of the coating, which makes it easier to install and helps reduce the loads on the supporting structures.

Secondly, metal tile sheets can quickly close the large roof areas, which is very convenient, especially if you choose a two-screw option.

The step of rafted under metal tile is set in the range from 60 to 95 cm, since a relatively small weight of the roof does not require increased resistance. Because of the low weight, the coating can be reduced and the thickness of the rafter.

As for the thickness of the heat-insulating material used for the insulation of the roofs of metal tiles, the specialists believe that the device under it is for greater confidence in reliability can be used thermal insulation 20 cm, in other cases, 15 cm.

A feature of the roofs covered with metal tile is the possibility of condensate.

You can avoid this by organizing when installing rafted ventilation: 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 frame of rafters under such a coating, as a natural (ceramic) tile, it is necessary to remember its high weight.

Compared to other modern tile materials harder at 10 or more times. Given this feature, experts recommend using an extremely dry wood under it, in order to avoid sagging after drying.

For rafters in this case, it is necessary to use a bar with a cross section of 50 - 60 mm * 150 - 180 mm; The width of the step of the rafter feet is set in the range of 80 - 130 cm, with the more degree of the lip of the roof, the greater the distance between the axes of the rafter.

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

Considering the size of the tile (as a rule, its length does not exceed 40 cm), it is necessary to correctly calculate the width of the shade of the crate, stroke.

From the length of the skate, you need to take away the length of the lower row and the number of centimeters between the crate and the last bar.

Frame for Ondulin, Profile and soft roof

Relatively new in the materials market are such types of roofs as professional flooring and Ondulin. At the same time, they are successfully used both when equipped with a duplex and a hip roof.

The weight of these materials is almost equal to the weight of the metal tile, so the calculation of the width of the step will be similar to the calculation when placing metal sheets. The step of rafters under the professional flooring is determined from the range of 60 - 90 cm, under the ondulin - 60 - 100 cm.

A sufficient thickness of the rafter when coating the roof ondulin and a professional flooring - 50 * 200 mm.

If you need to increase the distance between the rafted centers, then you can increase the strength of the transverse crate.

The rule of the installation of the crate under the professional flooring is similar to the installation of the crate under the metal tile: the last board must be taken more wider than the rest (as a rule, by 15 cm thicker).

An ONDULIN clamp must be made solid to increase material resistance to various weather conditions.

Speaking about the device of the rafter system under the soft roof, it is worth remembering the types of such material presented in the markets: this is a rolled type of roofing and bituminous tile.

The name itself suggests that for a soft roof, a very strong base is necessary, which will allow to withstand heavy snow cover, impulses of wind and heavy rains.

The main requirements for the frames of the roofs under the soft roof - they must be durable and smooth.

Strength should be calculated on the thickness of the snow characteristic of the region in which the structure is erected, and on the average weight of an adult man to have the ability to troubleshoot.

A smooth roof should be for the reason to exclude the possibility of sagging under the influence of the above-mentioned weather phenomena.

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

If the step is still greater, it will be necessary to make a draft crate to which the main, solid one will be mounted.

The counterclaim will help the soft roof. Do not ferment and increase its service life. For a solid cage, a 30 mm board is often used or an OSB 20 mm plate.

If the soft roof is provided as a coating for a holm roof with an organization of an attic space, then it is necessary to think about its insulation, having thought over the heater for laying insulation, hydro and vaporizolation.

These are all the subtleties of the roof skeleton device under a soft roof.

Slinged for slate roof

Despite the wealth and diversity of modern materials, the old-good slate remains quite popular. It is not always the use of expensive roofing coatings is justified, and it was then an asbestos-cement sheet comes to the rescue.

Slate weight is quite impressive, while its laying does not require some kind of grand crate. All because such a roof itself is strong enough.

For the construction of a roofing frame in this case, rafters are required with a cross section of 150 * 40 mm and a ram with a cross section of 35 * 35 mm for the crate.

Timber for the construction of a frame is to stack and withstand some time to give the same level of humidity.

After the drying process is completed, it is necessary to determine the bend. Stropile legs are recommended to install a concave part (tray) up - so water in the case of hitting the rafter rolled down, bypassing the attic space.

Before installing the installation, the bars check for the content of bitch and rejected, because the bitch material may not withstand the severity of the roof.

The rafter fasteners in this case produce nails, the optimal length of which is 15 - 20 cm.

Nails must flash the timber throat, but the peeking ends should never bend, because the mobility of the structure is required.

When drying and deforming a tree, this technique will allow preventing slate sheet cracking.

The cutter for the device of the slate roof can be solid or sparse. Solid make from a sheet of OSB or plywood and more often used with a flat slate flooring.

Spruce is characteristic of laying on her wave slate. For a sheet with a standard size of 1.75 m, the shaft step is about 80 cm. Making the crate more frequent makes no sense, since slate has a sufficient margin of safety.

After analyzing the materials of the article, it is possible to independently engage in the construction of a row and holm roof frame, determining their features and properties of the roofing materials.

It will not be superfluous to recall that the calculation of the rafter step is a very responsible occupation, and it is necessary to approach its markup responsibly, because it will avoid mistakes and accelerates the work in the future.

As you know, the roof of any structure is its upper part that can connect protective and decorative functions. Protects the roof mainly from the inwards on top of the building of atmospheric precipitation, at the same time as its kind, material and color of the roofing may emphasize the architectural feature of the building.

Wooden bars, of which the rigid roof frame is called rafters, the selected roofing material is already mounted directly on them.

As the buildings carry different functional filling (for example, residential buildings or production and technological buildings) and the roofs of various buildings differ from each other. Their form can directly depend on climatic conditions: from wind load or the number of drop-down snow. The roof from the latter is difficult to clean if its tilt is 30 0 and less, and the high "sailbo" of a high roof can be a serious problem with wind gusts of more than 18 m / s.

Among the huge variety of roofs, the majority usually consists of a roof and a set of building structures that hold this roof.

One of the main elements of these structures are, as a rule, wooden bars, which is mounted roofing. These bars are called rafters or farms. They are also elements of rigidity that determine the mechanical strength of the roof, as well as those guides that determine the angle of inclination of the roofing coating.

The rainfall can be located either from one to another outer wall of the building, with a specific inclination, or from the center (skate) of the roof to the outer wall. In the first way, single-sided roofs are arranged, on the second - double.

It can be assumed that the closer to each other these farms rafters will be located, the more reliably there will be a roof coating.

However, excessive use of materials takes the design and leads to the rise in the cost of construction. Therefore, the question of how to put rafters is one of the fundamental roofs when designing the roof.

The rafters are two species: the so-called "hanging", based on their ends only on the outer bearing walls, and those that are based on one of their ends on the inner bearing wall of the building or the inner column. Farms of the last species are called "urban".

The correct placement and fastening of these elements of the building is the basis of the fact that its upper part is not deformed under the influence of possible loads.

How to put rafters

General provisions

When designing the roof of the structure, determining the number of farms and the distance between them, necessarily take into account the desired cross section of the timber used for the device of the rafter, determine its material and the optimal length of the rafylic. Usually, the device rafter uses a timber from coniferous trees, cross-section from 50x150 mm (considered the most used) or more.

The length of the farms directly depends on the size of the building box, the type of roof, as well as from its height. The cross section of the used bar and the distance between the rafters define the strength of the carrier structure for the roof. The distance between the axes of the neighboring farms is called and is calculated when designing the roof. In practice, the applied step can take the value from 600 to 2000 mm. The specified step is interconnected with farm long: than they are shorter than, the longer the distance among themselves can be installed.

There is a generalized method of calculating the specified distance. It lies in the fact that the table defines the preliminary step of the rafted. Measuring then the sink length of the roof of one slope along the bottom edge, the resulting distance must be divided into a step defined on the table. The result obtained and the unit added to it after rounding to the most side will correspond to the number of required rafters for one rope of the designed roof.

The exact distance between the "legs" axes of the neighboring farms will be obtained by dividing the length of one roofing slope on the number of rafalines calculated for it.

In this way, it is possible to determine, after which the minimum distance can be installed solutions so that the roof bearing structure would correspond to the settlement requirements for the load.

However, the above method does not take into account possible additional loads on the design associated with the use of different roofing coatings, from slate to ondulin. Does not take into account the need to organize the free space between farms for placing the canvas or plates of the insulated insulation for the roof.

In the case when it is planned to use insulation tools, the width of the cavins or panels of which is known to be known, you can immediately determine what distance it is necessary to install rafters. It is recommended in such cases a step to equate to the width of the insulation, minus from 1.5 to 2 mm.

Recommendations for choosing a step of rafters for different roof coverage

For the roof from the corrugated floor, the step is selected from 600 to 900 mm. In this case, the timber is recommended for the optimal section - 50x150 mm.

For severe roofing from ceramic tiles, an increased load on rafters is characterized, about 60 - 70 kg / m 2. Step is recommended ranging from 800 to 1300 mm. Moreover, it may increase in proportion to an increase in the angle of inclination of the roof. For example, the distance between the farms should be no more than 800 mm if the angle of inclination of the roof does not exceed 15 0. With an increase in the specified angle to 70 0, the step can be increased to the maximum. The cross section of a bar for such a roof is recommended from 50x150 to 60x180 mm.

The device of the supporting structure of the roofing coating for metal tile is not much different from the standard one. The material, compared with ceramics, is easier almost twice: the load on 1 m 2 does not exceed 30 kg. Application recommended a timber with dimensions of 50x150 mm. Some features of the attachment of the upper ends of the rafter are associated with ensuring the ventilation of the metal roof to prevent the appearance of condensate.

The slate roof is an optimal solution for numerous buildings, despite the fact that this material is recognized as harmful and prohibited for use in European countries.
Recommendations for the installation of a rafter for roofing coating from a wavy slate type: They are put in between 600 to 800 mm, there may be 50x100 or 50x150 mm.

For roofing coating from ONDulina, it is proposed to be performed according to the recommendations acting for a slate roof. The modern innovative material ondulin looks like slate, but it is easier for the last time in five.

Determining the interconnection distance for multicate (tent) roofs are made separately for each slide. For the buildings in which the "box" is collected from logs or timber, the lower end of the rafaline is attached directly to the upper part of the outer bearing wall, and not to a special bruus, laid around the perimeter of the upper part of the building (Mauerlat). This installation method makes a particularly high error price when determining the step of the rafter, since it is very difficult to eliminate this error.

Carrier Slinged Design for Dersightener Roof

For such roofs, carrying structures for the roof are usually performed from a wooden bar. The step of the rafted for a skate with a length of no more than 15 m can be selected from 800 to 1000 mm. For attic with skates, more than 15 m long is recommended to use rafal farms from metal.

It should be noted that for all types of roofs, when determining the step, the rafter should take into account the presence of existing vertical structural elements of the building passing through the attic and roof. Such elements include chimneys and air ducts. When the calculated point of installation of the farm with the place of passing the existing pipe or other elements of the building, whose transfer is impossible to another part of the attic, it is necessary to change the plan for the placement of the rafter.

If the change in the specified plan for some reason is inappropriate, it is recommended that the rafter coincided on the place with the element of the building, to arrange it so that it is interrupted at the point of passage of the pipe. Moreover, the ends of this farm are cut in front of the transmitted pipe and after it should be based on the corresponding jumpers connecting the adjacent rafyroids.

It should be borne in mind that the nodes of such a "interception" of the farm should be performed with the necessary reliability and quality, which makes it possible to comply with the calculated reliability of the roofing coating structure.

It should be noted that the installation of rafters is part of a whole complex of very serious and very important construction works on the roof of the building. Being a constructive element of the roofing system of the roofing of the building, the rafters are indicated in terms of the roof project, which reflects the results of calculations of various possible loads.

Such calculations should take into account all sorts of factors affecting the designed structure in the complex:

• necessary and sufficient height and inclination of the roof;
• optimal material for the roofing device;
• parameters for its placement on the required crate and the overall weight of roofing;
• the required carrying capacity of the rafter design as a whole and the corresponding parameters of the Stropilin in particular;
• the method of fastening the roof to the walls of the building and the condition of the walls.

And other equally important data, without taking into account the constructed building and its roof may not withstand a variety of loads.

Therefore, in order not to deal with the inept agencies of the sore effects, it is better to entrust the issues related to the design and construction of buildings, professionals specialists who have the necessary experience and knowledge. At least in the part that concerns the calculations of the load on the rafter structures.

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

The distance between the basis of roofing rods is not a permanent value and depends on the following components:

• kind of roofing;
• the angle of tilt of the skate;
• the species of the proposed roofing material;
• the size of the cross section of the rafter.

Before proceeding to the construction process of the top construction of the house, calculate the calculation, determining the optimal, distance between the rafters.

Rapid roof rafters

Duscal roofs received the greatest distribution in our country. They represent a construction having two parallel planes, with an angle of inclination relative to the horizon from 20 to 50 degrees.

With an insufficient bias, the roof of the bone roof in the snow-covered areas is the risk of accumulating large snow masses, which can lead to the destruction of the structure. The increase in the corner of the rods in the regions with the predominance of strong winds is also fraught with high load and the risk of fault not only the roof, but also the structure as a whole.

Horry roof

Most of the private houses have an exploited underpowering space called attic. This design is distinguished by the increased slide height, which is caused by the need to create a residential room of a convenient height. As a rule, the slots of the attic roof are broken, having a changing angle of the slope. For their installation, a double rafter system is used.

The steepness of the lower semi-column of the attic roof significantly exceeds the tilt of their continuation. Plague load perceived by them is not large. Due to this, the rafters at the bottom can be installed with a maximum step. The upper skate rods are recommended to mount with a reduced gap from each other.

Single roof rafters

For household buildings and some houses in private, roofs that have one skate are used. Due to the restriction of the angle of inclination on them there is high pressure. Experts are recommended for a single-piece roof rafter use a lumber of an increased cross section, with the installation of the minimum step from each other.

When calculating the distance on which the roof beams are installed, special attention should be paid to the magnitude of the snow load in a particular area. With a small slope, this characteristic is of great importance. The roofing material for such roofs is better to choose with a minimum one's own mass, which will reduce the bending load.

Slinged Walm Roof System

The most complex in construction is considered the rafting system of the holm roof. This species is called a four-page, since the roof is formed not only by side, but also additional end skates, where the installation of the rafter is carried out not at the horse, but on the angular tents. This makes special requirements for the organization of roofing frame.

Under the holm roof, the attic is not satisfied. This is associated with a small angle of inclination of the rafted and the roof as a whole. In the event of an increase in the angle of the rods to the horizon, the distance between the rafters is increased, with a decrease - on the contrary. An additional aspect of the calculation also used the roofing material.

The dependence of the step rafters from the roofing material

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

The correct choice of material has an impact not only on the upper, but also on all other parts of the design of a residential building and other buildings. No wonder, when designing a foundation, it is necessary to decide in advance with the choice of roof.

Roofing from the professionalist

Currently, one of the most common roofing materials is a profiled sheet produced by galvanized or subsequent polymer coating. The following parameters will be attributed to the distinctive features of the professionalist:

1. High corrosion resistance;
2. As a result, long-term (more than 15 years) service life;
3. Easy installation even without the necessary qualifications;
4. The low mass of the sheet (weight 1 m 2 is 4-5 kg).

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

Roofing from metal tileage

The second common type of steel roofing materials is a metal tile. This kind of professional leaf, successfully imitating natural clay material, but with a smaller mass (10 or more). A feature of rafters for metal tile is a smaller section.

When choosing, at what distance, install rafters, first of all, should be guided by a dynamic load. Like a professional sheet, metal tile is not demanding of the size of the rafter feet and is well mounted on the crate of an inch coniferous boards. All this makes the metal roof of a small-time.

Scroll system for Ondulin

In the 21st century, a more durable and light analogue came to the change of wavy sheet materials - Ondulin. Among others - the most lightweight material. The mass of the sheet does not exceed 6 kg.

The small thickness of Ondulin sheets at the corners of the skates is less than 15 o, requires the arrangement of a solid crate of plywood sheets, for example, which will require the corresponding step of the rafter. This should be paid attention to the calculations.

Slate roof

Not so long ago, the widespread material was wetted from an asbesto-cement mixture, called slate. High mass and fragility are the main disadvantages, however, he finds his fans in the construction of various economic buildings.

The high mass, comparable to the weight of the clay tiles, will not allow the same rafter system as under metal tile. Construction standards defined the minimum angle of the roof of the roof from slate in 22 o and more. Otherwise, the load from the material and the rafter system with the crate exceeds the permissible parameters. The step of inclined bars, like their cross section, are selected individually in each case.

Polycarbonate roofs

In recent years, an artificial polymer material - polycarbonate has become more and more often on the roofs of the veranda. Available in two versions - monolithic and cellular. The first in its properties is similar to ordinary quartz glass, but significantly surpasses its strength. The second has smaller mechanical properties, but high thermal insulation and light effect.

Cellular polycarbonate is standardly much easier than a monolithic fellow. It is used as a roof without the use of the crate under the condition that does not exceed the ½ width of the material sheet. The high strength of the monolithic analog also allows to avoid transverse rafyles of elements. Sufficient flexibility allows semicircular roofs on a metal frame, the step of which does not exceed 0.9 meters.

Thematic material:

Raftered under the soft roof

The original pattern can be obtained due to the use of soft roofing materials, accumulating with the adhesive layer. Install that are installed on a solid crate of plywood or OSP. The step of the rafter should allow the fastening sheets, so it is chosen to a multiple ½ width. Subject to the standard sizes of plywood 1520x1520 mm, the mid-scene distance between the rafters will be: 1520: 3 \u003d 506 mm.

Step rafted under the insulation

Installation of residential underpants spaces are often combined with styling of insulation sheets in a rapid gap. The most common plates with dimensions of 600x1000mm. These parameters and use as starting.

Scheme calculating step rafters

For construction standards, the pitch of the roof rafters is located in the range of 0.6 - 1 meter. Its 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 how much distance should be between rafters for your specific construction conditions. According to the directories, the magnitude of wind and snow loads is determined in the area.
2. the roof length is divided into the desired distance, adding a unit. The resulting result will be equal to the number of rafting legs, which are installed on one rope of the roof. In the event that the value is not an integer, it is rounded.
3. the roof length is divided into the calculated above the number of rafters, we get the final step in meters.

For example, when the slope of the slope of 30 degrees, the maximum distance between the solid roof rafters is 0.6 measure. Length is assumed to be 16 meters. Hence:

1. 16:0,6+1=27,66;
2. rounding the result, we obtain 28 rafters on one slut;
3. 16: 28 \u003d 0.57 meters - the inter-axis interval of the rafter feet for these specific conditions.

As can be seen, the calculation technology is not complicated, but this is just an approximate scheme. Consideration of many other parameters specified above can make certain adjustments.

The design of the bartal roof for private houses is most often selected, as it is an optimal option for ease of installation and ease of operation, by strength and reliability, as well as in a stylistic solution. The bartal roof is differently called forcep and has two slopes that can be located relative to each other under the same or different angle, that is, it can be an anailed or versatile triangle. The last option is increasingly can be found among new buildings, as it becomes a fashionable style solution. And, besides originality, such a roof has some positive features that simplify its operation.

Such type of the rafter system can be used under all types of roofing materials, but the lattice, fixed on the rafter, has its own parameters for each of the coatings.

Diva roof: the rafter system under which has its own characteristics, should be carefully studied and is designed to still beyond the purchase of materials and carrying out its installation. Let's try to figure out these questions.

Dyed Designs of Duscal Roofs

To begin with, it is necessary to understand which constructions of the bantal roofs are, as you will have to choose the most appropriate for a particular structure.

• Simple equilateral duplex design

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

Symmetry in this system helps to achieve uniformity of the load on Mauerlat and carrier walls. With the right choice of a cross section for the arrangement of the rafter system and Maurolalat, these parts will provide the reserve of safety for long-term operation of the roof. Additional reliability of the design will give properly installed racks, soot and tightening.

The disadvantage of this system for arrangement inside the attic space of the room is that after installing the walls and the ceiling, a large area occupy a deaf zone in the corner areas of the designs that remain unreasted.

• Simple asymmetric duplex design

The asymmetric duct design differs from the traditional system by the fact that its slots are located at different angles. So, one of them is usually more than 45 degrees, which makes it possible to increase the useful area of \u200b\u200bthe attic space in which it is quite possible to equip a residential premises, naturally, with due insulation.

Another important advantage of such a design can be smaller on the area of \u200b\u200bthe skate, which is recommended to plan from the leeward side of the structure, where a large number of snow is always assembled on the roof. Small in size, but with a large steep slot will not delay the large snowdrifts on its surface.

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

• Loars banta design

This double rafter system can be called a rarity, although thanks to this location of the skates in the attic space, a sufficiently large room is formed, which can be used for a residential or economic room.

In addition to such a rafter system, the attic option of the rafter can be attributed to the broken bantal design.

Both skaters "breakdown" - explicit winnings in the useful area of \u200b\u200bthe attic room

3 - Stand installed on a litter.

4 - raftered.

5 - doom.

The slotted system differs from hanging in what is installed on a structure having internal capital partitions. Capital Internal Walls are used to secure Lenzny on them, on which racks are installed, supporting the skunk run, with which the upper ends of the rafter legs are fastened. Then on the rafters fixed the boards of the crate.

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

fastening for timing

Hanging rafter system

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

1 - bearing walls.

2 - Mauerlat.

3 - raftered.

4 - doom.

5 - tightening (Rigel).

The hanging system of rafters is mounted on two external bearing walls, which is pre-fixed by Maurylat. This roof option can be applied only if the distance between carrier walls is no more than 7000 mm, since besides them, an additional support for the rafter design of the roof is missing. Such a system is usually equipped with tightening, reinforced by slopes - these elements will remove part of the load from the walls of the structure.

In addition to crowd and hanging systems, there are combined options that include individual elements of the same design.

When the rafter systems are selected, recommended before buying materials, make a detailed drawing of the roof with populated sizes - it will be easier to calculate the number of all the necessary and amount for their acquisition. In addition, such a scheme will help to make assembly work. But in order to draw up a drawing, you will have to spend some

How to calculate the parameters of the bartal rafter system

Correctly calculate the parameters of elements for mounting work - it is very important. To do this, it is first recommended to compile a list of all necessary and make calculation step by step. All calculations should be made with a reserve of 10 ÷ 15%, not allowing excessive savings, which will be to the detriment of the quality and strength of the structure.

If this part of the work is decided to do it yourself, you must necessarily be asked for technical documents developed by specialists, for example, placed in SNiP.

The main settlements of the calculation will be three interrelated values \u200b\u200b- the steepness of the skate, the height of the skate over the overlap and the length of the rafter feet. Next, having linear parameters, it will be necessary to decide on the cross section of the material for the rafted. But it already, in turn, depends on the loads falling on the rafter system.

Loads on the truss system

Loads on the truss system are divided into three categories:

• Permanent loads. This category includes those that will constantly keep in the voltage of the rafting system -, insulation, if it is provided, roofing, windproof, hydro and vapor barrier film, fasteners, finishing materials for the inside of the attic. The weight of all the elements and materials needed for the roofing "cake" is summed up, and on average the 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 the roof system is used with hanging rafters.
• Short-term load. Such loads occur periodically and can have a different effect on the design. These include such impacts:

— Weight of people in repair work;

— climatic temperature effects;

— Possible loads from the land.

These external loads lie in a great dependence on the features of the construction region. In addition, their magnitude directly depends on the steepness of the rods. For example, snow load will play a crucifier on gentry skates. With increasing the roofs of the roof effect of snow pressure decreases, but the dependence on the wind exposure grows. On the rods of steepness over 60 degrees, the snow load is also charged at all, but the roof sailiness increases at times, and the wind becomes the dominant external influence.

Data for calculations can be found in Snip 2.01.07- 85 * "Loads and Impact" in the "Snow Load" sections and "Wind Loads". At the same time, it is necessary to take into account not only the region of the location of the house, but also the place of its construction is lowland or elevation, a separate structure or surrounded by other buildings.

A convenient load calculation algorithm will be shown just below.

• Special loads. This category includes factors such as seismic effects, hurricane wind, deformation processes due to the sedimentation of the soil, which are commonly called force majeure circumstances. It is impossible to foresee everything, and in order for the roof so that the roof sustain all these tests is recommended to lay an additional margin of strength when purchasing materials and installation of the structure.

If the roof is installed on the old building, it is necessary to calculate the supporting ability of the foundation and walls, since the new roof may have more weight than old. Such calculations can only be professionally implemented specialists, but it is necessary to make such calculations necessarily, otherwise you will have to not only change the roof, but also to repair the entire structure. At the same time, it will be necessary to provide the roof project in which all its parameters will be indicated.

The angle of inclination of the rafting system and the height of the skate

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

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

So, any double rafter system, no matter, symmetrical or not, can be represented as a triangle.

His vertices:

- point "but" - This is an external point of intersection to this top adjacent angle "A", which determines the steering wheel steering.

- point « b » - Top of the skate.

- point "from" - intersection of the sheer line from the skate with overlapping or just the upper wall level.

Famous initial value - « D » The length of the root of the triangle. For a symmetrical roof is half a span. For asymmetric options, it may be different, it is easy to determine.

"N" - the height of the skate over the base (overlapping);

« L »- the length of the rafter foot, which, if desired, can be increased by magnitude "M"for the formation of an eaves.

According to famous trigonometric ratios:

N \u003d.D × TGA.

Thus, it is possible either from a given angle value and determine the height of the skate, or, on the contrary, by planning a certain height of the attic room in advance, decide on the steep slide.

All this makes it easy to make the calculator located below. Changing the value of the angle " BUT" You can come to the optimal meaning of the height " N ".

The content of the article

When building the roof, first choose the type of the rafter system. This means that rafters must be a hanging or weak or the whole rafter system will consist of those and other rafters, i.e. combined. Calculate the distance between the rafters is not difficult, knowing the amount of loads that will act on the entire roof.

Loads are temporary and constant. Continuous loads include:

• weight of materials of the solo system itself;
• the weight of the roofing material;
• the weight of the roofing pie elements, if the roof is done insulated;
• the weight of the interior decoration of the attitude of the attic.

Temporary loads include: the weight of snow cover, the weight of a person in the production of roofing works and maintenance of the roof during operation, wind load and the weight of possible water flows in the summer.

What are the calculations based on?

The distance between the roof rafters is also calculated based on the selected material and the cross section of the rafter. All calculations are conducted at the design stage of the house by specialists of design organizations. To do this, they use reference documents and construction standards and rules governing this or that step of the rafter, the shaft step and other settlement values.

When building a private house, rarely who orders the project, where on the basis of calculations is recommended, what distance between the rafyles need to withstand. Most often, the developers rely on the experience of masters and trust themselves to conduct all calculations at the place. However, there are also such who wishes to make the calculation of the rafter and independently build a roof.

In this case, they must first of all decide on the type of roof, choose which the attic will be heated by residential or cold, since the type of the rafter system and the calculation of the distance between the rafters directly depends on these parameters.

Distance between Single Roof Slingers

Calculation for a single roof is the easiest. In the rafter system, it is not provided for racks and sidelines - only the rafted themselves. Such a roof is equipped most often on the utility rooms, garages, baths, etc.

The pitch of the sideline roof is presented in the table below and depends on the cross section of the bar:

If the developer wants to independently make loads on the rafter system, it will be useful for it to familiarize himself with such documents as Snip 2.01.85 "Loads and Impact" and "Changes with SNiP 2.01.85", where maps of climatic regions of Russia are laid.

As a material for the construction of the rafter, the wood of coniferous rocks is chosen, whose humidity is 20-22%. Boards, bars and other types of lumber must be smooth without swivel, rot, bitch and blue.

All wooden elements should be treated with antiseptics and antipirens to protect the tree from rotting and fire. The material used, the length of the rafter legs and the cross section of the bar also affects the calculations (we look at the table):

Approximate calculation

The step rafter is nothing but the distance between the rapid legs. As a rule, for residential individual homes, this indicator is 0.6-1.0 m.

At the magnitude of the step, the rafter influences a significant number of factors. The calculation of the desired amount of rafting legs is made in the following way:

• The length of the roof skate length is measured. After that, the amount obtained is divided into the selected step rate between the rafters.
• Then the unit is plusing to the resulting value and is rounded in a large side to get an integer. So get the number of required rafter feet for a given length of one roof slope.
• After that, the entire length of the roof of the roof is divided into the resulting integer (the number of rapid legs) and the result is the distance between the axes of future rafters, which is called the rafted step.
• The axis should be held in the center of the rafted. However, for a different type of roofing, the step of the rafter can change, it also changes depending on the corner of the roof slope.

for example : The length of the roofing slope is 16 meters, and the step value between the rafters is 0.6 meters. Consequently, 16 / 0.6 + 1 \u003d 27.66 \u003d 28 meters (the rafter is necessary for the device of the skate)

The greater the angle of the slope, i.e. than the roof is steeper, the step of the rafter can be done great. This is explained by the fact that the load on the steep roofs is distributed not to the entire plane of the roof, and mostly is transmitted to the bearing walls.

Stropil for ceramic tiles

Ceramic tile - material having a decent weight. Therefore, for the device, the roofing of the tiles should count on the cross section and the length of the rafter, given that one square meter of ceramics weighs almost ten times more than the weight of the metal tile.

• If in the design of the rafter system, it is supposed to arrange a tightening of the rafter, then its cross section should be increased.
• The rafters themselves must be made of dry healthy wood, their cross section should be 50x150 or 60x180 mm.
• The step of the rafter is made in the range of 0.8 -1.3 m for the coating of ceramic tiles, and its exact definition depends on the angle of the slope.

The higher the roof, the step of the rafter can be wider. For example, at an angle of a downhone 15 degrees, a step will be 80cm, and if the angle of the skate will rise to 75 degrees, the distance between the rafter footsteps will increase to 1.3m.

Another circumstance affects the magnitude of the step of the rafter - this is the length of the rafter feet. What they are longer, the step of them decreases. This is explained by the fact that at the maximum length of the rafter, elevated loads on the deflection are created. They can be reduced if you arrange a system of supporting racks, subposses and other elements of the rafter system that take part of the loads from the rafter.

Rafted for roofs from metal tile

The rafter system under metal tile is not much different from other terring structures. But in view of the fact that it has weight several times less than a ceramic tile, rafters and all other elements of the roof design can be performed with a smaller margin of strength, that is, a smaller cross section. The difference in the weight of the tiles of clay and metal is about 35 kg per 1 m square.

The step of the rafted under metal tile, as a rule, make 0.6-0.9m. The metal tile is widely used to cover country houses, in which attic rooms are often provided, therefore the roof is done insulated. The step of the rafter in such structures is configured under the dimensions of the insulation, which is inserted between the rapid legs.