The quality and durability of the roof is largely dependent on the correct calculation of the step of the rafter. It affects the laying of the insulation, fastening the roofing material and the installation of the challenges. Pay attention only to the requirements for the distance under roofing sheets, then problems can arise with insulation plates. And on the contrary, driving under the dimensions of the insulation you can make a frame too weak, and the threat of collapse will arise. How to correctly calculate the distance between the roof rafters? Talk about this in our article.
As a rule, a step between rafters depends on several factors. But usually the distance ranges between 0.6 and 1.2 meters. These indicators are rounded, in practice, the distance may differ for several centimeters in a smaller side. To accurately determine, the following calculations must be performed:
- Determine the length of the skate, measuring on the front side of the house. Suppose that it turned out 17.8 meters.
- Divide the resulting indicator on the planned step of the rafter. If it was decided that the distance between the beams will be 0.8 meters, then 17.8 / 0.8 \u003d 22.25.
- Next, the result is rounded in a large side and add a unit: 23 + 1 \u003d 24. At this stage, the number of required rafters is determined.
- Now we calculate the distance between the beam axes. For this, the length of the skate must be divided into the number of rafters: 17.8 / 24 \u003d 0.74 m.
So, you define the real distance at which rafters should stand for a roof from metal tile or some other material.
Often, specialized calculators are used when planning the roof frame. Basic data contributes in them and get a ready-made result. Nevertheless, the program should not completely trust, as some conditions can only take into account a person. When calculating, you can understand how the system works, what loads are valid. If necessary, adjustments are made, reinforcing or facilitating design. An independent calculation will help more accurately determine the desired step of the rafted two-tie and single-sided roof.
Calculation of the step depending on the roofing material
For each coating, their own norms and sizes that are presented to the rafter system are developed. The main factors are the strength of the material, its weight and resistance to external loads. Consider the main types of coatings.
Professor
The step of the rafted under the corrugated floor may vary from 0.6 to 0.9 m. The final result depends on the additional conditions that will talk below. If for some reason the step should be greater, add a transverse board with a large cross section. At the same time, the rafter is usually selected with dimensions of 50x100 or 50x150 mm.
In addition to the rafter, the cape of 30x100 millimeters is used. The gap between the boards should be about 0.5 meters. It can be more, it all depends on the type of professional flooring and the height of the wave. Clamps protruding beyond the borders of the eaves must have a thickness of 1.5 cm more than usual. This is done at the calculation of the need to fasten the ventilation, chimney or drainage.
Ceramic tile
The main complexity of the design of the rafter frame under ceramic tiles is the weight of the material of la roof. He is heavier than the professional flooring 10 times and per square meter ranges from 40 to 60 kg.
Under such a coating is used dry beams, with humidity of only 15%. Their cross section should be either 50x150 or 60x180 mm. With such indicators, the maximum allowable distance between the rafters can be 1.3 meters. The minimum permissible step through which it is possible to put rafters is 0.8 m. On the final solution affects the bias of the roof: at 15 °, the step is made of 0.8 m, at 75 ° - 1.3 m.
The calculation of a rafter foot is also taken into account than it is shorter than it, the greater the gap, and vice versa. In addition, if the slope is less than 45 °, and it is planned to move on the surface, the beams are set in increasingly 0.85 m.
The distance between the shell boards is selected so that each root intersection has its own base. The standard length of the material is 400 mm, and the amount of the allen during installation varies between 55 and 90 mm. It turns out that the distance between the central axes of the crate can be either 310, or 345 millimeters.
Metal tile.
In recent years, the question is especially acute: how to determine the distance between rafters for metal tile?. It simulates a more expensive ceramic material, but it has the positive properties of the professional flooring. Installation of such a coating is simple and does not require large financial costs. All this makes the material attractive for roofs of private houses.
The mass of metal tiles is less ceramic, so a simple frame is required. The sections of the beams are reduced to 50x150 mm and increases the step between the crate. Step rafted under metal tile ranges between 0.6 and 0.95 m.
Ondulin
The permissible step for coating from ONDULIN is 0.6-0.9 meters. Standard cross section of rafted - 50x200 millimeters. Such dimensions will allow you to withstand the generated load of roofing pie to the bathous roof.
On top of the counterclaims fasten the crate of bars with dimensions of 40x50 millimeters. The step between the central axis is 600 mm.
Additional factors
When calculating the step, the rafter draws attention not only to the type of roofing coating. Many other points are taken into account, the data on which can be found in reference books and slips. Here are some of the factors:
- Snow and wind load. The more snow falls in the winter and the stronger the wind blows, the smaller the distance between the beams should be. But if you increase the angle of the roof of the roof over 45 °, then it is allowed to increase step.
- Selection of insulation. To reduce costs on the insulation plates, it is recommended to take into account their standard dimensions. Release mats width 600, 800 and 1200 mm. If you neglect this condition, then a large number of subsoring will appear, the bridges of the cold and the construction will delay.
- Lumber quality. It takes into account the breed of wood, grade and section. As mentioned above, the strength affects how well the beam was dried. By purchasing wood, pay attention to the evenness and availability of vice in the form of bitch and traces of pests.
- Overlapping and tightening beams. If under the double-tie roof, the attic floor is equipped, then the maximum distance between the rafters is 0.75 meters.
The calculation of the distance between the beams for a two-sheet and a single-pate roof is different. Even if there is a few rods, for everyone you need to make calculation individually. This is especially true to buildings with different front cornices.
Taking into account all these factors can be determined at what distance to install rafters. Although all calculations can be made independently, since reference data is in free access, it is better to turn to professionals. They have experience in design, faster determine the required distance between the rafters. So, you will avoid possible errors and you will be safe.
The construction of the rafting roof system and the subsequent roof flooring is the most important steps in any construction. This is a very complex, conjugate comprehensive training, which includes the calculation of the main elements of the system and the acquisition of the materials of the desired section. Not every novice builder will be able to design and sanit a complex design.
However, often during the construction of the sale buildings, structures of economic or utility purposes, garages, canopies, arbors and other objects, the special complexity of the roof is not at all - the simplicity of the design is emerging, the minimum number of materials and the speed of work, which are quite silent For independent execution. It is in such situations that the rafting system becomes a kind of wig -beric
In this publication, the main focus is made on the calculations of the single roof design. In addition, the most typical cases of its construction will be considered.
The main advantages of single-sided roofs
Despite the fact that not everyone likes the aesthetics of the building, over which a single-table roof is mounted (although the question itself is ambiguous), many of the owners of country sites in the construction of buildings, and sometimes even a residential building, choose this option, guided by a number of advantages Similar design.
- Materials for a single rafter system, especially if it is erected over a small economic extension, it will take quite a bit.
- The most "tough" flat figure is a triangle. It is he who is based on almost any rafter system. In a single-table system, this triangle is rectangular, which significantly simplifies the calculations, since all geometric relations are known to each who ended up high school. But this simplicity does not affect the strength and reliability of the whole design.
- Even if the leading independent construction, the area owner never faced the construction of the roof, the installation of a single-table rafter system should not cause excessive difficulties from him - it is quite understandable, not so complicated. Often, at the overlapping of small hozpostroops or other incoming structures it is quite possible not to do something that without calling the team of specialists, but even without inviting assistants.
- With the construction of the roof design, the speed of work is always important, naturally, without loss of quality - I want to protect the structure from the weather whims as possible. Under this parameter, a single-table roof is definitely a "leader" - there are practically no complex connecting nodes in its design, taking a mass of time and requiring high-precision fit.
How significant are the shortcomings of a single sump system? Alas, they are, and with them also have to be reckoned:
- An attic with a single-board roof or is not expected at all, or it turns out so small that it is necessary to forget about its wide functionality.
- Based on the first point - there are certain difficulties in ensuring sufficient thermal insulation located under the single room roof. Although, of course, it can be corrected - nothing prevents the insulation of the roofing shelter itself or to arrange insulated attic overlap under the rafter system.
- Single roofs are usually done with a slight bias, up to 25 ÷ 30 degrees. It entails two consequences. First, not all kinds of roofing coatings are suitable for such conditions. Secondly, the significance of the potential snow load increases dramatically, which should be taken into account when calculating the system. But with such slopes, the effect of wind pressure on the roof is significantly reduced, especially if the slope is correctly located - in the windward side, in accordance with the prevailing winds in this area of \u200b\u200bthe terrain.
- Another disadvantage, perhaps, can be attributed to very conditional and subjective - this is the appearance of a single-piece roof. He may not come to the soul of lovers of architectural delights, they say, very simplifies the look of building. This can also be argued. The first - simplicity of the system and the economy of the construction often play still a decisive role in the construction of utility structures. And three times - if you see an overview of residential buildings, then you can meet very interesting design options, in which the stop is made on a single-sided roof. So, as they say, do not argue about tastes.
How is a single-table soling system calculated?
General principles for calculating the system
In any scenario, a single roof system is a design of the sleeve rafting legs installed parallel to each other. In itself, the name - "urban" suggests that the rafters are based on (crowded) into two rigid points of the support. For the convenience of perception, we turn to a simple scheme. (By the way, to the same scheme will be returned more than once - when calculating the linear and angular parameters of the system).
So, two points of support of the rafting leg. One of the points (IN) Located above odd (BUT) for a certain value of exceeding (h). Due to this, the slope of the skate, which is expressed by the angle α.
Thus, as already noted, the basis of the construction of the system is a rectangular triangle ABCin which the base is the horizontal distance between the points of the support ( d.) - most often it is the length or width of the built building. Second catat - excess h.Well, the hypotenuse is the length of the rafter leg between the points of the support - L.Corner at the base (α) determines the roof ridge steer.
Now consider the main aspects of the selection of the design and the settlement of the calculations somewhat more.
How will the necessary slope of the skate be created?
The principle of the arrangement of the rafter - parallel to each other with a certain step, with the necessary angle of the slope of the skate - the general, but this can be achieved in various ways.
- The first is that even at the stage of developing a project of the building, the height of one wall (shown in pink) is immediately laid with exceeding h. relative to the opposite (yellow color). The two remaining walls, which goes parallel to the roofing slope, is given a trapezoidal configuration. The method is quite common, and although somewhat complicates the process of erection of walls, but it extremely simplifies the creation of the very rapid roof system - almost everything is ready for this.
- The second method can, in principle, consider the first to be the first. In this case, we are talking about frame construction. Even at the project development stage, the vertical frame racks on one side above the same magnitude is laid in it. h.compared to the opposite.
On the above graphs and on those that will be placed below, the schemes are made with simplification - not shown by Maurylalat, passing along the top end of the wall, or the strapping bar on the frame structure. It does not change anything in principle, but in practice without this element, which is the basis for mounting the rafter system, can not do.
What is Mauerlat and how is it mounted on the walls?
The main task of this element is the uniform distribution of the load from the rafter feet on the wall walls. The rules for selecting the material and on the walls of the house - read in a special publication of our portal.
- The following approach is practiced in the case when the walls have an equal height. Exceeding one side of the rafter legs over the other can be provided with the installation of vertical racks of the height h..
The solution is simple, but the design is obtained, at first glance, somewhat unstable - each of the "rafting triangles" has a certain degree of freedom to the left - right. This is simply eliminated by the fastening of the transverse bars (boards) of the crates and the firmware of the rectangular frontal part of the roof from the facade side. Fronton triangles remaining on the sides are also sewn with wood or other material convenient for the owner.
fastening for timing
- Another solution to the problem is the installation of a roof using single-table farms. This method is good in that it is possible after the calculations are perfectly assembled and fit one farm, and then, taking it as a template, make the required number of exactly the same structures on Earth.
Such technology is convenient to apply in the case when, by virtue of its long-length, require a certain amplification (this will be discussed slightly below).
The rigidity of the entire rafter system is already laid in the farm design - it is enough to install these assemblies to the Mauerlat with a certain step, entry on it, and then combine the farms with the strapping or transverse bars of the crate.
Another advantage of this approach isferring and the role of the rafter foot, and the beams of overlapping. Thus, the problem of thermal insulation of overlapping and flow lifting is significantly simplified - everything will be ready for this immediately.
- Finally, one more case - it is suitable for the situation when a single roof is planned over the house of the extension.
On the one hand, the rafter legs are based on the frame racks or the wall of the erected extension. From the opposite side there is a capital wall of the main building, and the rafters can rely on the horizontal run fixed on it, or on individual attachments (brackets, mortgage bars, etc.), but also aligned horizontally. The line of attachment of this side of the rafter legs is also done with exceeding h.
Please note that despite the differences in the approaches to the installation of a single-table system, in all versions there is the same "rafting triangle" - it will be important for the calculations of the parameters of the future roof.
Which way to provide a roofing scat?
It would seem - a celebrating question, however, with him it is necessary to decide in advance.
In some cases, for example, if, options are special and no, the skate should be located only in the direction of the building, so that the free stock of the storm water and the tales snow is provided.
There are already certain opportunities for the preferably structure. Of course, it is not enough when the option is considered, in which the rafter system is placed in such a way that the direction of the slope accounted for the facade part (although this solution is not excluded). Most often, bias are organized back or one of the sides.
Here you can already take on the criteria for choosing the external designer design of the built building, the features of the area of \u200b\u200bthe site, the convenience of laying the communications system of stormwater collection, etc. But still it is necessary to keep in mind certain nuances.
- The optimal arrangement of a single-table roof is in the windward side. This allows you to minimize the wind effect that can work with the lifting application of the strength vector when the slope turns into a peculiar wing - the wind is trying to rip the roof up. It is for single-sided roof that is essential. During the wind, the same in the roof, especially at small angles of rolling rods, the value of the wind exposure will be minimal.
- The second aspect of the choice is the length of the skate: it can be placed along it with a rectangular building along it or across it. It is important here to take into account the fact that the length of the rafted without amplification can not be infinite. In addition, the longer the span of the raftered by the inter-point points of the support, the thicker should be in the cross section of the lumber, which comes to the manufacture of these parts. This dependence will be explained a little later, already during the calculations of the system.
Nevertheless, the rule is practiced that the free length of the rafter legs should usually not exceed 4.5 meters. With an increase in this parameter, additional elements of the construction enhancement are provided. Examples are shown in the illustration below:
Thus, when the distance between opposite walls from 4.5 to 6 meters, it is already necessary to install an entropilege (pan), located at an angle of 45 °, and resting on the rigidly fixed support bar (liten). With distances up to 12 meters, you will have to install a vertical rack in the center, which should rely on or reliable overlap, or even on the capital partition inside the building. The stand is also resting in a litter, and in addition, a boar is installed in each of the sides. This is all the more relevant due to the fact that the standard length of sawn timber usually does not exceed 6 meters, and the rafter foot will have to do composite. So without an additional support, it will not work out anyway.
A further increase in the length of the skate leads to an even greater complication of the system - there is a need to install several vertical racks, with a step of no more than 6 meters, with a support for the sperm walls, and with the binding of these racks by the fights, with the installation of the same subspaves and on each rack, and on Both external walls.
Thus, it is necessary to think well where it will be more profitable to orient the direction of the roofing rod also for considerations of simplifying the design of the charter system.
self-tapping screws
What angle of the ridge of the skate will be optimal?
In the overwhelming majority when it comes to a single-table roof, an angle of up to 30 degrees is selected. This is due to a number of reasons, and the most important of them has already been mentioned - a strong vulnerability of a single-table design to a wind load from the facade side. It is clear that by following the recommendations, the direction of the skate is oriented into the covered side, but this does not mean that the wind on the other hand is completely excluded. The steeper the angle of the slope - the more significant the lifting force becomes, and the greater load on the breakdown will be the roofing design.
In addition, single-sided roofs with a large tilt angle look somewhat incomprehensively. Of course, it is sometimes used in bold architectural and design projects, but we are talking about more "landed" cases ...
It is too gently sloping, with an angle of a slope to 10 degrees, is also not too desirable, for the reason that the load on the truss system from snowsells increases sharply. In addition, with the beginning of the melting of the snow, the appearance of a nondes on the lower edge of the skate, which makes it difficult to make a free approach of melt water.
An important criterion for choosing an angle of steepness of the skate is and conceived. It is no secret that for different roofing materials there are certain "frames", that is, the minimum permissible angle of the roof slope.
The angle of the slope of the skate itself can be expressed not only in degrees. Many masters are more convenient to operate with other parameters - proportions or percentages (even in some technical sources you can find a similar measurement system).
Proportional calculus is the ratio of the length of the span ( d.) to the lifting height of the skate ( h.). It may be expressed, for example, by the ratio of 1: 3, 1: 6 and so on.
The same relation, but already in absolute value and the percentage given to the percentage gives a slightly different expression. For example, 1: 5 - it will be a steepness of the skate in 20%, 1: 3 - 33.3%, etc.
To simplify the perception of these nuances, a table with a graph-diagram showing the ratio of degrees and percentage is placed below. The scheme is completely scaled, that is, it can easily translate some values \u200b\u200bto others.
The red lines show the conditional separation of the roof: up to 3 ° - flat, from 3 to 30 ° - the roof with a small slope, from 30 to 45 ° - the average steepness, and above 45 - cool slopes.
The blue arrows and the corresponding numeric designations (in circles) show the established lower bounds of the use of one or another roofing material.
 |
|||
|---|---|---|---|
| № | The magnitude of the slope | Type of permissible roofing (minimum level of slope) | Illustration |
| 1 | from 0 to 2 ° | A completely flat roof or with an inclination angle to 2 °. At least 4 layers of a rolled bitumen coating applied in "hot" technology, with a mandatory upper sputter of fine-flow gravel, drowning into molten mastic. | |
| 2 | ≈ 2 ° 1:40 or 2.5% | The same as in paragraph 1, it will be enough 3 layers of bituminous material, with a mandatory spript | |
| 3 | ≈ 3 ° 1:20 or 5% | At least three layers of bituminous roll material, but without gravel swelling | |
| 4 | ≈ 9 ° 1: 6,6 or 15% | When using rolled bitumen materials - at least two layers pasted on mastic hot way. It is allowed to use some types of professional flooring and metal tile (according to the manufacturer's recommendations). | |
| 5 | ≈ 10 ° 1: 6 or 17% | Asbesto-cement slate wavy sheets of reinforced profile. EuroShorter (singleline). | |
| 6 | ≈ 11 ÷ 12 ° 1: 5 or 20% | Soft bituminous tile | |
| 7 | ≈ 14 ° 1: 4 or 25% | Flat asbestos cement slate reinforced profile. Professional flooring and metal tile - practically without restrictions. | |
| 8 | ≈ 16 ° 1: 3.5 or 29% | Sheet steel roofing with a folded connection of adjacent sheets | |
| 9 | ≈ 18 ÷ 19 ° 1: 3 or 33% | Slate asbestos-cement wavy conventional profile | |
| 10 | ≈ 26 ÷ 27 ° 1: 2 or 50% | Natural ceramic or cement piece tile, shale or composite polymer tiles | |
| 11 | ≈ 39 ° 1: 1.25 or 80% | Roofing coating made of chips, duncut, natural shingle. For lovers of special exotic - creating roof | |
Owning such information and having hints for the future roofing, it will be easier to decide with the angle of steepness of the skate.
metal tile.
How to set the desired angle of the skate?
Let us turn again to our basic scheme of the "rafter triangle" placed above.
So to set the desired angle of the slope of the skate α , it is necessary to ensure the elevation of one side of the rafter foot h.. The ratio of the parameters of the rectangular triangle is known, that is, to determine this height - the difficulty will not submit:
h. = d. × tG. α
The value of Tangent is a table value that is easy to find in the help reference or in tables published on the Internet. But in order to simplify our reader as much as possible, a special calculator is located below, which will allow calculations literally in a few seconds.
In addition, the calculator will help solve, if necessary, and the inverse problem - changing the angle of the slope in a certain range to select the optimal value of the exceeding, when this criterion becomes determining.
Calculator for calculating the top point of the installation of the rafter
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.
Before the construction of the rafter system and the organization of the roof, a number of simple events should be conducted, which will perform the key to the integrity of the design. This includes choosing a type of roof.
It can be hanging or a weak, and there may be a combined option. This is when two types are combined in the same structure.
Temporary loads are snow cover on the roof in winter, water flows from the rain in summer, the wind, the load that a person has, conducting service work during the operation of the roof and others.
The permanent loads include the weight of the most rafter system, the weight of the roofing material and the underpants cake, the mass of the interior decoration, if the building is assumed to organize the attic on the attic.
When creating a single-table or double-screw roof project, first of all choose the type of rafter design, the angle of inclination of roofing rods, as well as materials for construction construction. When calculating the distance between the rafters, the load should be taken into account that will affect the roof of the construction during operation.
- The weight of the roofing material;
- The weight of the building materials, of which the rapid roof frame was built;
- Weight of insulation, vaporizolation, waterproofing;
- The weight of the mansard finishing material or a residential attic room.
The roof of the structure also affects the following temporary loads:
- Snow weight;
- The weight of the employee performing the maintenance and repair of the roof.
For the correct calculation of the step, the rafter should be taken into account the cross-section of the elements of the design of the structure, the presence of the roof thermal insulation, the type of crate and roofing coating. Calculations should be performed on the basis of Snip 2.01.85 "Loads and Impact".
Video on how to perform the calculation of the rafter system:
Distance calculation scheme between rafters
All counts are conducted at the design stage of the building. They are performed by the designer engineers of that organization where the project of the house was ordered.
If the project was not compiled and the person relies only on the experience of masters who are entrusted to the construction of a roof, then in this case, you need to become familiar with the relevant documentation. It SNiP 2.01.85 "Loads and Impact" and "Changes with SNiP 2.01.85".
There is a detailed schedule of calculations and a map of the country's climatic zones.
Further are determined with the type of roofing system and the purpose of the attic room. After all, depending on whether this is a unwapped attic or a living room, then the load on the rafters will be different, and, therefore, the course of calculations changes.
In the calculations, the climatic zone must be taken into account, where work is carried out, the construction material of the rafted and its cross section.
So, the step of rafters is the distance between the rapid legs. It can vary within 0.6 m - 1.0 m.
The course of calculations:
- first, the length of the roof skate length is measured. Next, this value is divided into the length of the step of the selected material. This indicator is taken from SNIPA and for each building material, it is unique and depends on the segment of the beam;
- the result of previous calculations add a unit and rounded towards a larger number. Thus, it turns out a whole value and it indicates the required amount of beams;
- the length of the roof slide is divided into the resulting integer. The result will show how many beams need to build a high-quality and durable roof.
Experts point to the next feature of the roofs with a steep slide. When they are erected, you can reduce the distance between the rafyles. This is caused by the movement of the load from the beams on the wall of the house.
Distance between rafyles for different types of roofing
However, the calculation of the distance between the rafters is so unambiguously carried out. After all, this indicator depends on the type of structural roof material used.
Distance between the beams for the roof from metal tile
The average weight that has on the roof equals 35 kg / m². To keep it with the roof should have a step of 0.6-0.9m. It uses a timber with a cross section of 50x150mm. 
However, metal tile is often used in the construction of country houses and cottages. And in such structures, the attic room is often equipped under a residential room.
This leads to the installation of roofing pie and all sorts of insulation, which, in turn, have an additional load on rafters. Therefore, it is recommended to increase the cross section of a bar for beams. This is especially true of regions with low air temperatures in winter. Recommended dimensions of rafted 50x200mm.
In addition, the distance between the rafters can be customized under the width of the insulation. This will not only increase the carrying capacity of the roof, but also simplifies the arrangement of the heat insulating layer, will reduce the consumption of the insulation.
Distance between the beams for the roof of the corrugated
The recommended step of the rafted for the roof is 0.6 m - 0.9 m. However, it is necessary to take into account the operational characteristics of the profession itself. If the step is big, then the professional flooring "will lead" under its weight, thereby changing the geometry of the roof and its technical characteristics.
To prevent such a need to mount additional boards with a large cross section as a crate. They will perform the role of rafters in some way.
The cross section of the rafter for the roof from the professional flooring 50x100 mm or 50x150 mm. The crate is performed from the board, cross section of 30x100 mm.
Distance between the beams for the roof of ceramic tiles
Ceramic tile - heavy material for the roof. It has a load on rafters in the range of 40-60 kg per m². That is why the distance between the rafters in this case will be minimal - 80-130 cm. The more weight, the smaller the distance. However, the last indicator may decrease, depending on the angle of inclination of the roof. What it is more, the less you can mount the beams.
Mounting design for Ondulin
The step of the rafter feet for ondulin should be 60-100 centimeters. For the manufacture of rafters used lumber with a cross section of 200 × 50 mm. This is enough to create the most durable and reliable rafter frame.
It should be noted that under this roofing material you need to make a solid crate. Due to this, the material will better resist snow loads and solar effects.
Sometimes the shuthent type of crates is used. For its manufacture, a wooden timber is used. The distance between adjacent elements should be less than 30 centimeters. This option is usually more costly compared to a solid crate.
Slinge system under slate
Roofing coating from slate is considered the most common in Russia. The main reason is the low cost of this roofing material, the ease and speed of the installation work. Also important advantage is the ability to replace individual damaged slate sheets to new ones.
The distance between the rapid legs for the roof from slate should be 80 centimeters. Such a distance is considered the most optimal.
The lattice under the slate should be extended. For its manufacture, a board is applied or a sequence with a cross section of at least 30 millimeters. It is such a thickness of a bar or board that is required for the qualitative distribution of the weight of roofing and winter precipitation.
When erecting the rafter system, you should remember the constant reserve of strength. It may be needed in case of bad weather and with mechanical loads.
Stropyl frame under the soft roof
The soft roof includes soft tiles, bitumen polymer and bitumen rolled materials, as well as roofing membranes. The main advantages of the roof of this type include low weight, as well as the absence of the need to build a massive system of rafters.
The minimum step of the rafter is 60 centimeters, and the maximum - 150 centimeters. When erecting a rafter frame for a soft roof, the angle of inclination should be taken into account. In other words, the smaller the hijacking of the inclination of the roofing rods, the less you need to make the distance between the rapid legs for the solid crate.
The distance between the rafters also depends on the material from which the lamp will be manufactured. The greater the thickness of the sheet of plywood or OSP, the more you can take the step of the rafter.
Roofing from sandwich panels
The roof of this type is usually erected on the construction of angar type or houses from the sip-panels. The sandwich panels have a bending rigidity, so they do not need to install traditional rafter feet.
If the spans from the top of the wall to the skate of the double roof are small, then the sandwich -panels are mounted without additional supports.
With the length of the spans, more than 400 centimeters must be installed for additional runs. When building a roof from sandwich - panels on a residential building, a traditional rafting framework is often built. However, in this case, the distance between rapid legs can be made large, as they serve as a support for the runs.
Choose the distance between the rafters pushing out the length of the bearing walls and the length of the material for the runs. The roof of the sandwich panels can withstand high operational loads.
Erecting the rafter frame for polycarbonate
Recently, polycarbonate is often used in the construction of roofing. It is used in the construction of canopies, winter gardens and arbors. The rafting frame and the crate is made of metal or wood.
Polycarbonate differ in weight, which depends on the thickness of the sheet. The pitch of the polycarbonate crates should be from 60 to 80 cm. The crate made of metal or wood is attached to rafters (direct or arched shape).
The distance between the plumbing feet under the polycarbonate, as a rule, is 150- 230 cm. To properly calculate the distance between the rafters, it is necessary to take into account the glazing area, the thickness and size of sheets. It should also be remembered that polycarbonate sheets are mounted with small gaps.
The distance between the rafyles is one of the key parameters affecting the strength of the structure. The competent calculation of the installation step of the rafter allows you to build a roof resistant to high operational loads.
Loads on the roof and calculation of the rafter system
The development of a single-table or twin roof project begins with a selection of the type of a rafter system, an angle of inclination of the rod (the height of the roof) and the construction materials for the construction of the structure. The calculation of the distance between the rapid legs is performed taking into account the loads that the roof will test during operation. Permanent loads included:
- weight of materials from which a rafter system is made;
- roofing weight;
- the weight of the materials of the roofing pie (waterproofing, vapor insulation, insulation);
- weight elements of decoration of a housing attic or attic.
In addition to constant loads, the roof is experiencing temporary to which:
Upon step implies the distance between the rafters of one slope. Performing the calculation of a single-table, nipce or complex roof, usually follow the following scheme:
- it is measured the length of the future roof scope;
- the resulting value is divided into the optimal numeric value of the string;
- the unit is added to the value, the result is rounded;
- the bottom of the roof skate is divided into rounded result.
The final result will allow you to determine what distance you should put the rafting legs. The definition of the step cannot be extremely accurate, as it is required to take into account a number of additional factors, including the width of the insulation, the features of the edge of the crate under various types of roofing material. If the chimney roof is designed, the step can be adjusted to the location, so that it does not have to clean the part of the rafter and put the supporting structure, such as a special rafting system.
Distance between rafyles for slate
Slate - traditional roofing material. Its advantages include such characteristics as resistance to external influences (excluding mechanical) and low cost. Slate allows you to create a roofing coating, which can be replaced by the replacement of individual elements. Slate has a lot of weight and requires the installation of a fairly powerful rafting system. The calculation of the distance, on which it is necessary to put rafters for slate, is carried out taking into account the cross section of the bar for the manufacture of rafting legs.
The optimal solution is the installation of the system for slate, in which the gap between the rafters should be at least 800 mm. In order for the design to slate to withstand not only the weight of the material, but also increased external loads, the neckenet is performed from a bar or a board with a cross section of at least 30 mm. By performing the calculation of the rafter system for slate, it should be revealed that this material has sufficiently large restrictions on the choice of the angle of slope.
Raftered under metal tile
Metal tile is actively used as a practical and aesthetic roofing material during the arrangement of a single-table, plumbing, holm or complex roof. The framework for metal tile is built according to the standard principles. To calculate, at what distance it is better to put rafyroids, it is necessary to take into account the load and the angle of inclination of the roof. Metal tile characterizes a relatively low weight, so that it can serve as a replacement for old roofing coating from slate or ceramic tiles. At the same time, the rafters will not need to strengthen or change the step of their installation.
The standard step of rafted under metal tile is 600-900 mm. The cross section of the elements can be 50-150 mm - this is enough to create a reliable frame for metal tile. But if the insulation is assumed, the layer of which in areas with low winter temperatures should be 200 mm, for rafters for metal tile, it is recommended to use the 200x50 timber pump so as not to mount an additional system that holds the insulation. The gap between rafters for metal tile is better to fit under the width of the leaf or rolled heat insulator.
Profile: rafters and doom
Professional flooring refers to the easy and convenient in the use of roofing materials. A galvanized or covered with a decorative and protective layer, professional flooring can be used both for mounting a single-table roof of the utility room or garage and for a two-tie roof of a residential building. How to calculate the distance required to install rafters under the professional flooring?
To ensure the necessary stiffness of the design, it rafters under the professional flooring is enough to put 600-900 mm in increments. It is necessary to pay attention to the angle of inclination of the roof. The calculation shows that at high external loads, professional flooring is better laying on the system with a minimum step. But if the distance between the rafters under the professional flooring is close to the maximum, and the angle of the roof of the roof is small, the design is enhanced by using a more frequent crate. In this case, the pitch of the crate under the professional flooring should be about 50 mm, the width of the elements is at least 100 mm.
Slinged system for soft roof
The soft roof includes bitumen and bitumen polymer rolled materials, roofing membranes, as well as soft tiles. The soft roof characterizes the relatively low weight and the lack of the need to mount the massive rafter design.
The minimum distance between the rapid legs is 600 mm, the maximum is 1500 mm. When installing support under the soft roof, it is important to take into account the angle of inclination of the slopes: the less angle, the smaller the distance between the supports for the solid crate should be. The choice of material is also influenced by the thickness of the material for the crate - the thicker the sheet of plywood or osp, the greater there may be a step of installation of the rafting legs.
Ondulin: Calculation of rafters
Ondulin (bituminous slate) is laid on a flat solid crate made of sheet material. This allows roofing coating to successfully resist wind and snow loads. ONDULIN ONDULET BUILT ON THE REDUCE, which should be located in a step of 600 - 1000 mm, depending on the angle of tilt the two-screw or a single roof.
Scroll under ondulin is made from a bar with a cross section of 200 × 50 mm. Choosing, at what distance to put the rafter feet for the design of the ondulin, it is recommended to take into account the width of the insulating material to simplify its installation. This calculation allows to reduce the financial costs of roofing.
Sandwich panel roof
The roof of the sandwich is most often erected on houses from sip-panels or the construction of angar type. A feature of the sandwich is its bending rigidity, which allows you to do without installing traditional rafters. Small spans from the skate of the two-sheet roof to the top of the wall (or the distance between the supporting structures of a single-table roof) allow the installation of a sandwich without additional supports.
If the length of the span exceeds 4 meters, you need to install additional runs. To mount the roof of a sandwich on a residential building, a traditional rafter system is often installed, but in this case the rafter can be placed with a big step - they perform the support function for runs. The distance between the rapid legs is selected based on the length of the existing material for the runs and the length of the bearing walls. Sandwich technical parameters allow the roof to withstand high operational loads.
Polycarbonate: construction of the support structure
Polycarbonate has recently been actively used as roofing material. First of all, polycarbonate is in demand during the construction of arbors, canopies, winter gardens. The doomle and the rafter system for polycarbonate can be made of wood or metal.
Polycarbonate varies on their weight depending on the sheet thickness. The polycarbonate cable is recommended to perform 600-800 mm in increments. The lamp (wooden or metal) is mounted on rafters, which can be straight or have an arched shape. Typically, the gap between the polycarbonate rafters is from 1500 to 2300 mm. To correctly calculate, at what distance it is better to start rafters, it is necessary to take into account the area of \u200b\u200bglazing, the size and thickness of the sheets, take into account that the polycarbonate is attached to the gaps on the thermal expansion.
Distance between Double and Single Roof rafters
Find out how much the distance between the rafters needs to be done for a two-tie and single roof. The maximum distance between rafters for metal tile, ondulin and soft roof.
Distance between rafyles: Principles and examples of calculations of the step of a rafter system
The task is to correctly calculate the distance between the rafters - very responsible. From how seriously you begin to go to her decision, not only the reliability and durability of the roof will depend on, but all subsequent works on it: laying of the insulation, installation of roofing coating, setting the challenges. If you put a rafted step under the roof sheets, as many make it, it is not a fact that the insulation will then be included between the rafters. If you only focus on the insulation - the first winter with its abundant Russian snow will crush the rafter system. That is why the whole point is to pick up the optimal step of rafters on for all skates, and here we will teach you now.
What depends on the arrangement step of the rafter?
So, the distance between the rafyles is determined by such important factors:
- Roof shape (duct, single or multicate).
- The angle of inclination of the roof.
- The parameters of the timber that is used for the manufacture of rafters (width, thickness).
- The design of the rapid system (ulissive, hanging or sliding).
- The combination of all loads on the roof (the weight of the coating, atmospheric phenomena, etc.).
- Material of the crate (20x100 or 50x50) and its parameters (solid, with 32 cm spaces, 20 cm or solid plywood)
And each of these parameters should be taken into account what this article is about.
Decorative rafters: 0% load
First of all, decide with the most important point: the type of roof and its appointment. The fact is that the roof of a residential building in winter withstands a large snow cap, a permanent wind at an altitude and is often insulating it from the inside, but to the rafter system of a small arbor hidden under the crowns of trees, there are completely different demands.
For example, if you build pergola in its classical understanding, it does not matter exactly what the distance between the rafters will be, this is a purely aesthetic factor:
In the above illustration, it can be seen that even in such a building there is a step of rafters. After all, here it provides both aesthetic factor, and the rigidity of the structure itself. But choose a step arbitrary.
Functional rafters: detailed calculation
We approach the main question: What distance should there be between the roof rafters of a residential building? Here, be patient and carefully examine all the nuances.
Item 1. Wall Length and Sick Stroke
The first thing the installation step of the rafter on the roof of the residential building is usually choosing a constructive size of the building, although taking into account many other factors.
For example, the easiest way to install rafters in 1 meter increments, so it is standard 7 rafters with a length of 6 meters. At the same time, you can save, putting them with a distance of 1 and 2 meters, and it turns out exactly 5 rafters. You can also put up with a distance of 2 and 3 meters, but it is to strengthen the crate. But it is extremely unwanted to take a step of rafted more than 2 meters.
Paragraph 2. Effect of snow and wind loads on the shape of the roof
So, we stopped on the fact that the average distance between the rafters of the ordinary roof is 1 meter. But, if there is a significant snow or wind load in the area, or the roof is more or less common or just heavy (for example, covered with clay tiles), then such a distance must be reduced to 60-80 cm. But on the roof with a slope of more than 45 degrees it can be Even increase at a distance of 1.2 m-1.4 m.
Why is it so important? Let's figure it out. The fact is that the air flow faces in its path with a wall under the roof of the building, and there is a twist, after which the wind strikes the roof into the pannies. It turns out that the wind stream is like a ridicule of the roof, but at the same time striving to lift it. And in the roof at this moment, there are forces that are ready to rip it or knock on - these are two windward sides and one lifting.
There is one more power that arises from the wind pressure and acts perpendicular to the slope, trying to induce the roofs of the roof. And the greater the angle of inclination of the roof of the roof, the more safe wind power and less tangents matter. And the greater the angle of the skate, the less you need to put rafters.
Understand, make you a high roof or a common one, will help this map of the average wind load value:
The second point: in the Russian region, such an atmospheric phenomenon like snow constantly affects the standard roof of the house. And here, too, you need to take into account that the snow bag usually accumulates more on some side of the roof than another.
That is why in such places where such a bag is possible, you need to insert twin rafting legs or make a solid crate. The easiest way to determine such places on the wind rose: with a windward side, they put single rafters, and with leeward - paired.
If you are for the first time building a house, then I do not get your own worldview, and determine the average snow load for its locality according to official data:
Item 3. Question of insulation and standard width of mats
If the roof you will be insulated, then the step of the rafter is advisable to put under the standard dimensions of the insulation slabs, and this is 60, 80 cm and 120 cm.
Modern insulation today is selling a standard width, usually on the same standard step of rafters. If then take them and customized under the existing parameters, then there will be a lot of waste, cracks, cold bridges and other problems.
Clause 4. Quality and strength of the used sawn timber
It also has the most important thing that you use for the construction of the rafter system. So, for each breed of wood there is its own regulatory documentation, which concerns its bearing ability:
Because For the manufacture of a rapid roof system in Russia, pine and fir are most often used, their flexural strength and features of use have long been spelled out. If you use the wood of other breeds, you can display the correction factor.
In addition, if there are cross sections, wrinkles or holes for the bolts, in this place it is necessary to calculate the carrier ability of the bar with a coefficient of 0.80.
Paragraph 5. Distance between tightening and overlap beams
Another point: if the roof is built with the linked rafting farms, and their lower belt is used simultaneously as the ceiling beams, then the distance between farms needs to be made within 60-75 cm to take into account the design of the future floor.
Paragraph 6. Loads for rafting nodes
So, here are the main loads that act on the rapid roof system:
- Static, which includes the weight of the very rapid system, the weight of the roof lying on the roof of snow and the challenges.
- Dynamic, which includes the strength of the wind, unexpected damage to the roof, human weight and equipment for repair and similar factors.
And all these factors are capable at a certain point to affect the roof at the same time, and therefore there is a concept as critical value. This is exactly the value of loads in which the roof does not withstand and deform.
Therefore, if the building is built with significant spans, the steel rafting farms are necessarily applied. The fact is that the voltage in such rods is already absent, and the entire load falls on the nodes - compressive and tensile forces are affected here. And the distance between such farms is calculated depending on the type of roof and the design of the roof itself.
Usually, a unified farm is put with a span, a multiple of six, and therefore there is a distance between the farm nodes, a multiple one and a half meters.
Paragraph 7. The weight of the rafter system and roofing cake
Do not forget that the main purpose of the rafter is to keep the whole roof on itself, and its weight is crucial:
Paragraph 8. Convenience of roofing
It affects the distance between the rafters is also such a factor as the selected roofing coating. The higher the slope of the roof, the more roofing materials will be used. And what they are harder, the more likely they will have to put rafters. But what about a solid doom? The fact of the matter is that it has its own weight:
Each type of roof is its optimal step of rafters. After all, many standard sheets on the edges must be attached directly to rafters or the crate, and it is important that they coincide. Otherwise, the roof covering will easily turn into a daytime hell at height, believe me.
That is why even before the start of installation you need to make a layout, check all several times. And know some important subtleties for each of the types of coatings.
Determination of the totality of loads on the roof as a whole and raftered separately
So, we determined that, in addition to other constructive factors, a whole set of loads act on the rapid roof system at the same time: the weight of the rafter system, the snow cap, the wind pressure. After you fold all the loads together, be sure to multiply them to the coefficient of 1.1. So you will all calculate unexpected favorable conditions, that is, lay additional 10% percentage.
And now you only have to divide the total load on the planned number of rafters and see if each of them will cope with its task. If it seems that the design will be sickly - boldly add 1-2 rafters in the total, and you will be calm for your home.
You need to make a calculation for destruction, i.e. On the full load, which acts on the roof. All these loads are determined by the technical characteristics of materials and the bottom.
The standard roof construction is rafters, lattice runs, and each of these elements works only on the load that presses it precisely on it, and not on the overall roof as a whole. Those. For each separate stage, its load is valid, the overall, but divided by the amount of rafter legs, and the change in the step of their location, you change the area of \u200b\u200bloading area on the rafter - reducing it, or increasing. And, if you have a rafted step, it is inconvenient to you, then work with the parameters of the cross section of the rafting legs, and the total carrying capacity of the roof will increase by times:
With this calculation, try to achieve that the longest rafter was in your project for no more than six and a half meters, otherwise, splicing in length. Now explain more. So, on the roofs with the slope slope up to 30 degrees, the so-called "flexible elements" rafter. Those. They work on bending, and they have certain requirements. And the possibility of the deflection of the rafter is calculated by a special formula, and, if the result exceeds the norm, then the rafters are increased in height and again make a new calculation.
But on the roof with the bias of the warehouses more than 30 degrees, which rafters are already considered "flexible-compressed" elements. That is, they affect not only a uniformly distributed load, which causes the bending of rafters, but also efforts that are already acting along the axis of rafters. Simply speaking, here rafters not only bend a bit under the weight of the roof, but also squeezed from the skate to Mauerlat. In addition, a stretch must be checked and a bolt, which usually restrains two rafting legs.
As you can see, it will be cope with such calculations even far from the construction of a person. The main thing is to consider everything, to be attentive and ready to spend a little more time on the design, so that then all the work goes like oil!
Distance between raps: what step should be between rafters
Detailed instructions, how to correctly calculate the distance between the rafaceans of the roofs of different structures, with the accounting amount of loads and the material used.