Making the roof of a house is an important and responsible task. From quality top structure the integrity of the building and the peace of the residents will directly depend. Before starting work, it is necessary to select the right boards for the rafters and other roof parts, perform their high-quality pre-treatment and correctly connect them, preparing them for laying the roofing material.

Types of roofs

Currently for residential buildings and outbuildings, about ten different types of roofs are used. Some of them are more familiar to us, others are very rare. The main design options are:

Pitched roofs made using straight rafter systems:

• single-pitched;
• gable;
• hipped - hip and half-hip (with a ridge) and hipped (without a ridge);
• multi-tongs:
• conical

Pitched roofs with curved rafters:

• semicircular;
• hemispherical.

Almost all types of roofs are based on special parts that provide the roof with the necessary strength and give it the desired shape. It's about about the rafters.

Requirements for the quality of rafters

For the manufacture of rafters they use edged boards different sections. The most common parts are with a cross section of 50x150 or 50x200. Square beam or rectangular section is not used, since it cannot provide the necessary strength of the structure or will significantly make it heavier. Always install rafters on edge with your own hands. In this direction, the parts are more durable and not subject to bending.

Installation rafter system outbuildings

It is better to choose boards for work coniferous species. This is due to several of their features:

• the presence of resin prevents the formation of rot in the material;
• such parts have a relatively low weight, unlike, for example, birch boards of the same section;
• Coniferous material is more affordable, and it is much easier to find it at sawmills.

In addition, be sure to pay attention to elements in the wood such as knots. The presence of rotten falling out elements, which could lead to a decrease in the strength of the rafter leg in the future, is not allowed.

Preparing rafter system parts for installation

Before you begin installing the roof truss system with your own hands, we recommend that you carefully treat the surface of all wood parts used in the work.

Preliminarily inspect the purchased lumber and select the best quality. Boards with falling knots can be used in pieces, for example, when lengthening or for making racks (headstocks), struts, crossbars and other roofing parts. After selection sufficient quantity lumber is processed with special protective compounds, preventing rotting and burning.

You can apply fire retardants and antiseptics with your own hands in the following ways:

• by immersion;
• brush or paint roller;
• spraying.

Each method is good for one purpose or another. After one layer of impregnation has dried, it is recommended to re-treat. It is advisable not to mix formulations for different purposes in one container.

Choosing the optimal rafter system

Having selected quality boards 50x150, and having processed them with your own hands, we proceed to the installation of the rafter system. Before starting work on the perimeter of walls made of bricks or blocks, it is necessary to lay a mauerlat - a beam that will serve as a support for the lower parts rafter legs.

It is secured using threaded rods recessed into the wall or steel wire laid in the masonry seam. In buildings made of timber or logs, the role of the mauerlat is played by the upper crowns of the log house.

Depending on the size of the span between the walls of the house, we choose the option for installing rafters. There are systems with hanging rafters or layered ones, resting on an intermediate load-bearing wall.

Roof options: 1) With hanging rafters. 2) With layered rafters

The first type of structure has a horizontal transverse beam - a tie. In the second, this element is missing. For support, the ridge beam rests in several places on the intermediate wall of the house. This is not entirely convenient in the case of making an exploitable under-roof space - an attic, but it is optimal when big flights between the walls.

Determining the number of trusses

To determine the quantity required lumber to make rafters, for example, 50x150 boards, you need to calculate the required number of trusses - pairs of rafters connected at the required angle. On average, the span between them is 0.9-1.2 meters or slightly less. The determining criterion is the roofing material to be used.

Thus, for ondulin, the manufacturer recommends a rafter installation pitch of 0.6-0.9 meters, for metal tiles - one of the most common materials in last years– 0.65-0.95 meters. Great importance When choosing the inter-rafter distance, the slope angle of the slopes also plays a role, which depends on the snow and wind load in each specific area.

Having determined the step size, we divide the length of the walls by this indicator and add one to take into account the installation of gable trusses. Let's get the quantity rafter pairs. By multiplying this number by two we determine the required number of rafters. We calculate the length of the boards using the Pythagorean theorem, knowing the same slope angle and the span of the walls.

We install the rafter system - we assemble the trusses

Having decided on the number and size of the rafters, you can begin assembling the roof truss system with your own hands. As a rule, they try to install pre-assembled trusses. They can be made either attic floor at home and on the ground and ready to raise.

In any case, several templates will help make your work much easier.

The first of them is a rafter of the required length with the ends sawn at the required angle. If necessary, the edges can be cut not in a straight line, but with ledges to facilitate the installation of parts. For example, if the rafters are supported by timber, fastening can be done with steel angles, perforated steel tape or nails. In all cases, a figured cut will increase the quality of installation.

The second template is a sheet of plywood with stops nailed at the required angle, into which the upper ends of the rafters are inserted and connected by crossbars - transverse boards with a section of 50x150, providing the necessary rigidity of the rafter pairs. If free space allows, you can use one self-assembled truss as a template.

Installing farms

Trusses prepared with your own hands are lifted up. It is convenient to start installation with the outer pairs, called pediment ones. They are installed vertically, controlling the position using a plumb line or a board nailed to the wall of the house, and fix the position using additional slopes. The lower ends of the truss rest on the mauerlat beam or on the crowns of the log house. They are nailed to them with No. 100 nails.

Methods for attaching a rafter leg to a mauerlat

Having fixed the outermost truss, the rest are fastened, observing the span between them. To control this value, you can pre-cut spacers from a 50x150 board with your own hands and not measure the distance for each pair. After installation, the corners of the trusses are additionally connected with a ridge beam or board. Additionally, lathing will help secure the rafters.

The roof frame must be reliable and durable. But without proper calculations this is difficult to achieve. In the process of carrying out calculations, they determine at what distance to place the rafters on the roof.

What can result from an incorrect or inaccurate calculation of the loads to which the truss structure will be subjected? To the very negative consequences, ranging from deformation of the rafter legs and damage to the roof covering and ending with the collapse of the base of the roof frame. Therefore, when designing buildings, the list of mandatory calculations contains data on what the distance between the roof rafters should be. There is a certain technique that allows you to calculate this value.

Method for calculating the distance between rafters

The distance between the rafters on the roof is called the rafter pitch. As a rule, the pitch of the rafter legs in a roof structure usually exceeds one meter, and the minimum gap ranges between 60 centimeters.

Calculation required quantity rafters for a roof of a certain length and the pitch of the rafters are made as follows:

Rafter structure for metal tiles

When constructing suburban private real estate, metal tile roofing can be found most often. This roofing material is similar to decking made from clay tiles, but compared to it has a number of advantages. Sheet metal tiles are easy to install, so you can build a roof in a shorter time; the rafter system for metal tiles is also not complicated.

Metal tiles are lighter than ceramic products; the difference in weight sometimes reaches 35 kilograms per square meter depending on the thickness of the products (read also: " "). Thanks to a significant reduction in the weight of the roof deck, it becomes possible to reduce the thickness of the elements of the rafter structure and the cross-sectional dimensions of the sheathing bars, and to increase the installation pitch of the rafters.

Under the metal tile covering, rafter legs are mounted at a distance of 600 to 950 millimeters, while the cross-section of the construction material is 150 by 50 millimeters. According to experts, in this case, if you place insulation 150 millimeters thick between the rafters, then such thermal insulation will create comfortable conditions for staying in the attic room. At the same time, for greater reliability, it is advisable to choose 200 mm insulation.

When installing rafters, to ensure ventilation of the space filled with insulation, holes with a diameter of 10-12 millimeters are drilled in the rafters near the upper roof.

The technology for creating a rafter system for metal tiles does not differ significantly from designs for other types roofing materials. The only peculiarity is that the upper support of the rafters is mounted on ridge run from above, and not from the side, onto the ridge beam. The presence of a free zone between the rafters ensures air circulation under the roof deck, and this, due to the use of metal material, reduces the risk of condensation.

Rafter system of a pitched roof, main advantages and characteristics ").

The distance between the rafters of a gable roof is made taking into account the size of the heat insulator that is laid between them. The approximate step between the rafter legs is 1-1.2 meters (read: ""). Rafters regulate the amount of roof overhang.

The reliability of the roof and its service life mainly depend on how correctly the calculations are made.

One of the most important parameters rafter system is how far apart the rafters are located.

After all, the distribution of the load on the frame depends precisely on this desired parameter.

If the calculation is made incorrectly, deformation may occur and the roof will collapse.

Therefore, it is extremely important to accurately calculate the spacing when drawing up a roof project.

Basic principles of calculation

The pitch of the rafters is the distance from one rafter leg to the other.

When constructing roofs of private houses, this value is 1 meter.

But this figure is approximate.

To obtain Exact size interval, it is necessary to perform a calculation bearing capacity rafter system of the selected type.

For execution correct calculation the following scheme should be used:

• first you need to determine the length of the roof slope;
• Now the resulting figure should be divided by the value of the approximately selected rafter pitch. If you previously selected its value as 1 meter, then you need to divide by 1.

  If you chose 0.8, then you should divide by 0.8, etc.;

• after that, one is added to the result obtained and the resulting value is rounded up. This action is necessary in order to receive exact amount rafters that will need to be installed on one slope;
• the total length of the slope must be divided by the number of rafter legs obtained in the previous calculation. And we get the exact distance between them.

To understand this better, let's look at an example.

Having measured the length of the roof slope, we got 27.5 meters.

We choose a step of 1 meter to make it more convenient to count.

Further calculations will look like this:

Now we add the unit 27.5 m +1 = 28.5 m.

Round up to the nearest value and get the number 29.

That is, 29 rafter legs must be installed on one slope of our roof.

Now we divide the length of the roof by their number: 27.5/29 = 0.95 m.

This means that in our case, the pitch of the rafter legs should be 0.95 meters.

This is a general calculation.

In which the peculiarities of a particular roofing material are not taken into account.

And he can significantly change this parameter.

When you know what kind of material you will use on the roof, you will have to make some changes to the calculation procedure.

Optimal and minimum value

The step is a unit of calculation.

After all, it depends, first of all, on the load on the roof frame and the cross-section of the rafter legs.

You can take a thick board for their construction and make the interval between them 120 cm.

At this distance, the sheathing may begin to sag.

And how to install the insulation?

After all, most materials have a width of 1 meter.

So when calculating, they take an approximate step of 1 meter.

The minimum distance between is 70 cm.

And to receive optimal value For each material it is necessary to perform calculations.

Determining the pitch for a pitched roof

The pitched roof is the simplest.

After all, in roof truss Such a roof has only rafter legs.

There are no struts, racks, or braces in its design.

Such a roof is usually installed on garages, outbuildings, and bathhouses.

In order to determine the pitch of the rafters on pitched roof, you can use the table:

As can be seen from the table, rafter step depends on their length and cross-section.

Distance between rafters for a gable roof

A gable roof is much more common than a shed roof.

And it’s easy to explain such popularity: the design is very simple, but despite all the simplicity gable roof is distinguished by its reliability.

Its design can be easily adjusted to any climatic conditions and any roofing material.

When calculating the pitch of the rafters gable roof, everything is done according to common system calculation (see above).

If the slopes have the same length, then it is enough to perform calculations for one slope.

If the slopes are of different lengths, then the calculation is performed for each slope.

It should be remembered that limit values 70 and 120 cm.

What is the pitch depending on the roofing material

Ondulin

If ondulin is used as a roofing material, then the rafter system is constructed from pine boards with a cross-section of 50 x 200 mm, and the rafters should be located at a distance of at least 60 cm and no more than 90 cm from each other.

A sheathing of timber with a cross-section of 40 x 50 mm is laid on top.

Metal tiles

Metal roofing is most often used in the construction of country houses.

Because this material is much lighter than ceramic or cement tiles.

Although appearance very similar to her.

A small one makes it possible to use boards of a smaller cross-section when creating a rafter system, and to use thinner bars for sheathing.

Reducing the size of the elements of the rafter leg system, in turn, reduces the load on the walls of the building and its foundation.

When constructing a rafter system under metal tiles, the rafters are mounted in increments of 60 - 95 cm.

The cross-section of the material is 50 x 150 mm.

According to experts, if you place insulation with a thickness of 150 mm in the space between the rafters, then attic The most comfortable living conditions will be created.

To ensure ventilation of the space where the insulation is laid, when installing the rafter system, holes near the upper roof with a diameter of 12 mm are drilled.

The technology for manufacturing a rafter system for metal tiles does not differ significantly from the technology for manufacturing a frame for other roofing materials.

Its only difference is the installation at the top.

The upper support is mounted not on the side of the ridge beam, but on the ridge girder.

The presence of a free zone between the rafters allows air to fully circulate under the flooring, which helps prevent condensation from forming.

Ceramic tiles

The design of the system for ceramic tiles has its own characteristics.

After all, clay is used to make such roofing material.

And this is very heavy material.

If you compare metal tiles and ceramic tiles, the latter weighs 10 times more.

Accordingly, the rafter system is significantly different.

For 1 square meter of roof surface there is a load of 40 - 60 kg, depending on the manufacturer and brand of the product.

The rafters for such a frame system are made of wood that has undergone long-term drying.

Such wood should have a moisture content of no more than 15%.

A beam with a cross-section of 50 x 150 or 60 x 180 mm is used.

It's more reliable.

And the distance between can be 80 - 130 cm.

The exact value can be given if the angle of inclination of the slopes is known.

If the angle of inclination is 15 degrees, then the pitch of the rafters will be 80 cm.

And if the angle of inclination, for example, is 75 degrees, then the step can be greater - 130 cm.

The interval between rafters is not greater than 130 cm.

Also, when calculating the pitch of the rafters, their length is taken into account.

The larger the dyne, the smaller the distance between them.

The shorter the rafter legs, the greater the distance can be made.

If the angle of inclination is 45 degrees, then the roofer can safely move on the roof if the rafter pitch is 80 cm.

Corrugated sheet

When creating a rafter system for corrugated sheets minimum distance between is 60 cm.

The maximum size is 90 cm.

If for some reason the pitch of the rafters is more than 90 cm, then it becomes necessary to install cross-section boards of large cross-section.

The rafter legs themselves can have a cross-section of 50 x 100 or 50 x 150 mm.

Slate

Despite the appearance large quantity new roofing materials, asbestos-cement slate remains one of the most popular.

If you plan to lay slate on the roof, then the rafters should have a cross-section of 50 x 100 or 50 x 150 mm.

The distance between them is made no less than 60 and no more than 80 cm.

The lathing is made of timber with a cross-section of 50 x 50 mm or boards with a cross-section of 25 x 100 mm.

When installing any building structure It should be remembered that there are still unforeseen situations.

And, therefore, at and the distance between them it is necessary to provide a safety margin.

Video about installation of the rafter system.

Any rafter system is formed from numerous rafters, for the creation of which timber or boards are used. Most often, boards are chosen due to their affordable cost, but their strength is considered not too high compared to timber.

Important! The durability of the roof and the safety of living in the house depend on the quality of the selected lumber.

Requirements for rafter boards

Roof rafters can withstand significant impacts from snow, wind and roofing, therefore, in the process of their creation, certain rules must be taken into account that they must comply with.

Important! During the formation of rafters, not only right choice their size and cross-section, but also the material used to create them.

It is considered optimal to choose timber for rafters , but this material is expensive, so boards are often purchased to reduce costs. Only high-quality wood is selected, and often the choice falls on pine needles or larch.

When searching for boards used to create rafters, the basic requirements for them are taken into account:

Boards are purchased only from trusted sellers who provide buyers with information about the product. To do this, there must be special accompanying documentation, and it contains information:

• type of wood used to make boards;
• name and number of the product standard;
• Name production organization engaged in its production;
• number of units in one package;
• date of release of boards;
• dimensions of lumber, as well as its moisture content.

Important! Wood is natural material, therefore, various biological influences lead to its destruction, so it is important to choose the boards wisely, as well as protect them with special protective compounds.

Rafter boards must be treated before use different compositions:

• treatment with high-quality antiseptics that will prevent the material from rotting;
• impregnation with fire retardants that protect wood from fire;
• treatment with pest and insect repellents.

Only with the right choice of boards and after their high-quality processing is it possible to make rafters that not only high quality, but also resistance to various influences.

What size should the rafters be?

After being selected optimal board for rafters, you can begin to create a special drawing and diagram of the future rafter system. To do this, determine the cross-section, length, width and other parameters of the rafters, which, after manufacturing, will be connected to each other in the correct sequence.

The size of the rafters can vary significantly, since this parameter is influenced by many factors. These include the dimensions of the house and roof, the chosen design of the rafter system, possible wind loads and other similar influences. It would be best to use the following recommendations:

• the minimum size is 50x150 mm;
• if significant spans are created, then the size is selected 150x150 or 250x100;
• Larger rafters are often used if it is planned to build a large building shopping pavilion or other large building.

Important! To accurately know the optimal dimensions of the rafters for the roof, you need to correctly calculate this indicator.

For the calculation, it is important to determine what load will affect the roof as much as possible, which allows you to select the cross-section and other parameters of the rafters. Additionally, it is possible to use special standard values, but they do not take into account certain climatic conditions different regions, so experts prefer to carry out correct calculations, materials on the topic: , .

Correct determination of rafter dimensions

When determining optimal sizes rafters, it is important to consider how thick the board used to create the rafters should be.

Important! The thickness of the board has a direct impact on the strength of the products created from it.

It is advisable to use for these purposes a board whose thickness varies from 4 to 6 cm. If a rafter system is being erected in small buildings intended for economic use, then to reduce costs it is allowed to use boards 3.5 cm thick. For a residential building, it is recommended to choose products , the thickness of which will not be less than 5 cm.

When choosing the width of the board, you must take into account the length of the opening that overlaps the rafters. The longer the rafters should be, the wider the board used to create them:

• if the length of the rafters is approximately 6 m, then it is advisable to use a board whose width is approximately 15 cm;
• if the length of the legs exceeds 6 m, then the width of the board should be 18 cm;
• if you want to get an even longer rafter leg, then building up the elements is used, and the places where there is an overlap should be located next to the ridge part of the roof.

The cross-section of the rafters is calculated depending on a certain optimal distance between them, and the length of the elements is also taken into account. During work, it is necessary to decide what constant loads will affect the roof from wind and snow. The weight of the created rafter structure, the angle of inclination of the slope, as well as the length of the opening that needs to be covered are taken into account. When calculating, it is additionally taken into account how wide the structure is.

Important! To facilitate calculations, it is recommended to use special computer programs, which are freely available on the Internet, and with their help they not only ensure quick results, but also guarantee the accuracy of the values.

After determining the cross-section of the rafters, you need to decide at what distance from each other they will be installed. directly related to their cross-section, so if these parameters are not correctly determined, this may negatively affect the reliability and durability of the roof.

Important! It is allowed to reduce the cross-section of the rafters if special struts are used.

Basic rules for choosing boards

The rafter board must meet numerous requirements and conditions described above. To really choose quality material, it is recommended to use certain expert advice. These include:

Important! If it will be purchased material with a high humidity level, it is not allowed to use it for the construction of a rafter system, since it will be fragile, and there is also a danger for living in a house with such a roof, since after a short period of time the geometry of the structure will be damaged.

If several unsuitable elements are found in one batch of boards, it is not recommended to use them to create important parts of the roof, so they are used for additional elements.

Before installing the rafter system, the question arises at what step to install the floor beams. Correctly calculating the distance between the rafters means preventing subsequent deformation or even destruction of the roof frame. After reading the article to the end, readers will find out what the distance between the rafters should be for various types roofs and how to correctly calculate.

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

The span of the roof frame for the construction of a house made of timber usually exceeds 1 m, and the smallest permissible value is 60 cm, such indicators are indicated in GOSTs (see figure). You can correctly calculate the length of the rafters and their pitch using the following option:

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

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

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

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

Rafter pitch depending on material

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

1. Profiled sheeting. It has different thicknesses and tropezoidal curve shapes. Costs from 120 rubles.
2. Ceramic tiles. Expensive material from 670 rubles. Has 12 color options.
3. Metal tiles. It's more cheap material unlike ceramic and costs from 320 rubles.
4. Ondulin. A soft roof insulates the house from rain, hail, etc. Costs from 340 rubles.
5. Slate. Most economical option from 90 rub.

We will consider the step size for the most common types of coverage below.

Spacing of rafter beams under corrugated sheeting

The distance between the roof beams depends on the size of the sheet that the corrugated sheet has. The pitch of the roof frame beams under the corrugated sheeting is standardly taken to be no less than 60 cm and no more than 90 cm.

If this distance is greater, then boards with a larger cross-section are attached between the rafter beams. The cross-section of the rafter legs under the corrugated sheet is selected 50x100 or 150 mm.

The most important thing to consider when planning to attach corrugated sheets is the sheathing. It is made from boards with a cross-section of 30x100mm; it must be mounted with a span of 50 cm. It depends on the brand and thickness of the corrugated sheeting and the slope of the roof.

So a roof of 15º grade C 10 corrugated sheeting is mounted on continuous sheathing, corrugated sheet C 21 is mounted on the sheathing with a span of 30 cm. The largest corrugated sheet C 44 is mounted on the sheathing in increments of 50 cm to 1 m. In this case, before attaching the sheathing, you need to think about the free passage of the chimney, ventilation hood, etc.

Spacing of rafter beams for ceramic tiles

Specifics of installation of the rafter system for laying ceramic tiles due to the weight of this roof. Ceramic tiles are made from clay, and this roofing weighs 9-10 times more than metal tiles. The calculation of the load on the rafter system for ceramic tiles is 40-60 kg/m2.

Beams for the roof rafter system for ceramic tiles are made only from dried material. The cross section is suitable 50x150 or 60x180 mm. The standard distance between the rafters for a tile roof is 80-120 cm. The span depends on the slope of the roof. At an angle of 15º, the span between the rafters is 80 cm, at 750 every 1 m 30 cm.

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

When laying ceramic tiles, it is important to consider that you will need to walk on the roof. The maximum safe step of the rafter legs for such movement is 80 cm.

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

For a pitched roof for the construction of a house made of profiled timber, it is not difficult to make calculations. If the roof has a complex, multi-pitched shape, then each distance between the rafters is calculated separately per sheathing step. By securing the cord on the opposite side of the roof slope, you can easily mark the rows.

Features of the roof frame for metal tiles

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

Metal tiles weigh from 35 kg/m2 of roofing. This makes it possible to lighten the rafter structure and use beams of smaller cross-section. The step between the rafter legs of the roof frame increases and is equal to 60 to 90 cm. The beam is used with a section of 50x150 mm.

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

The design of the roof frame for metal tiles is not much different from corrugated sheets or ceramic tiles. But there is one small feature: the support from above is attached to the ridge girder from above, and not from the side as in other cases. This will create a ventilated gap under the metal tiles, which will prevent the accumulation of condensation.

Features of rafter legs for ondulin

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

Rafter beams under the ondulin are placed with a distance of at least 60 cm, maximum 90 cm. For the rafter system, softwood timber with a section of 50x150 or 50x200 mm is used. A smaller cross-section will not provide sufficient strength to the rafter purlins.

The sheathing on the rafters is made of material with a cross-section of 40x50 mm in increments of 60 cm. This is quite enough for fastening sheets of ondulin with an overlap of 30 cm. Ondulin is fastened with special nails, which are sold as a set.

Features of the slate rafter system

Slate is rarely used for roofing modern houses. But in dacha construction and household This material is irreplaceable in buildings. It is low cost and easy to install.

Slate rafters

Slate rafter legs are used with a section of 50x100 or 50x150 mm. The fastening spacing between the rafters is no less than 60 cm and no more than 80 cm.

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

The pitch of the rafter system under slate differs in the roof structure. For households buildings are often installed with a single slope.

Feature of the size between the rafter beams on a single-pitched and gable roof

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

Single-pitch rafter system

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

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

Gable rafter system

If you do not calculate the pitch of the frame of a pitched or other type of roof correctly, the roof may move away, and the beams will sag and bend due to the weight of the structure. In this case simple repairs If you can't do it, you'll have to redo the entire structure. Therefore, it is so important to correctly calculate the distance between the legs of the rafters, depending on the roofing material used: corrugated sheets, ceramic or metal tiles, ondulin or slate, etc.