Calculation of a gable roof yourself. Online roofing calculator or how to calculate the roofing covering for an attic roof yourself? Assessment of the condition and load-bearing capacity of walls and foundations

A gable roof is formed on the basis of a frame that combines the simplicity of the device and unsurpassed reliability. But the skeleton of a roof consisting of two rectangular slopes can boast of these advantages only if carefully selected rafter legs.

Parameters of the gable roof rafter system

You should start making calculations if you understand that the rafter system gable roof- this is a complex of triangles, the most rigid elements of the frame. They are assembled from boards, the size of which plays a special role.

Rafter length

Determine the length of strong boards for rafter system formula will helpa²+b²=c², derived by Pythagoras.

The length of the rafter can be found by knowing the width of the house and the height of the roof

The parameter “a” indicates the height and is independently selected. It depends on whether the under-roof space will be residential, and also has certain recommendations if an attic is planned.

Behind the letter "b" is the width of the building, divided in two. And “c” represents the hypotenuse of the triangle, that is, the length of the rafter legs.

Let’s assume that the width of half the house is three meters, and it was decided to make the roof two meters high. In this case, the length of the rafter legs will reach 3.6 m (c=√a²+b²=4+√9=√13≈3.6).

You should add 60–70 cm to the figure obtained from the Pythagorean formula. The extra centimeters will be needed to carry the rafter leg beyond the wall and make the necessary cuts.

The six-meter rafter is the longest, so it is suitable as a rafter leg

The maximum length of timber used as a rafter leg is 6 m. If a strong board is required longer length, then they resort to the method of fusion - nailing a section from another beam to the rafter leg.

Section of rafter legs

For various elements of the rafter system, there are standard sizes:

• 10x10 or 15x15 cm - for mauerlat timber;
• 10x15 or 10x20 cm - for the rafter leg;
• 5x15 or 5x20 cm - for purlin and bracing;
• 10x10 or 10x15 cm - for a stand;
• 5x10 or 5x15 cm - for a bed;
• 2x10, 2.5x15 cm - for laths.

Thickness of each part load-bearing structure roofing is determined by the load that it will experience.

A beam with a section of 10x20 cm is ideal for creating a rafter leg

The cross-section of the rafter legs of a gable roof is affected by:

The most significant effect on the cross-section of the rafter legs is the pitch of the rafters. An increase in the distance between the beams entails increased pressure on the supporting structure of the roof, and this obliges the builder to use thick rafter legs.

Table: rafter cross-section depending on length and pitch

Variable impact on the rafter system

The pressure on the rafter legs can be constant or variable.

From time to time and with varying intensity, the supporting structure of the roof is affected by wind, snow and precipitation. In general, the roof slope is comparable to a sail that is under pressure natural phenomena may tear.

The wind tends to overturn or lift the roof, so it is important to make all the calculations correctly

The variable wind load on the rafters is determined by the formula W = Wo × k x c, where W is the wind load indicator, Wo is the value of the wind load characteristic of a certain area of ​​Russia, k is a correction factor determined by the height of the structure and the nature of the terrain, and c is the aerodynamic factor coefficient.

The aerodynamic coefficient can vary from -1.8 to +0.8. A negative value is typical for a rising roof, while a positive value is typical for a roof on which the wind presses. At simplified calculation with a focus on improving strength, the aerodynamic coefficient is considered equal to 0.8.

Calculation of wind pressure on the roof is based on the location of the house

The standard value of wind pressure is determined from map 3 of Appendix 5 in SNiP 2.01.07–85 and a special table. The coefficient taking into account the change in wind pressure with height is also standardized.

Table: standard value of wind pressure

Table: k coefficient value

It's not just the terrain that affects wind loads. Great importance has a residential area. Behind the wall of tall buildings the house is in almost no danger, but in an open space the wind can become a serious enemy for it.

The snow load on the rafter system is calculated using the formula S = Sg × µ, that is, the weight of the snow mass per 1 m² is multiplied by a correction factor, the value of which reflects the degree of roof slope.

The weight of the snow layer is indicated in SNiP “Rafter Systems” and is determined by the type of terrain where the building is built.

The snow load on the roof depends on where the house is located

The correction factor, if the roof slopes tilt less than 25°, is equal to one. And in the case of a roof slope of 25–60°, this figure decreases to 0.7.

When the roof is sloped more than 60 degrees, the snow load is discounted. Still, snow rolls off a steep roof quickly, without having time to negative influence to the rafters.

Constant loads

Loads acting continuously are considered to be weight roofing pie, including sheathing, insulation, films and Decoration Materials for arranging an attic.

The roofing pie creates constant pressure on the rafters

The weight of the roof is the sum of the weight of all materials used in the construction of the roof. On average it is 40–45 kg/sq.m. According to the rules, per 1 m² of rafter system there should not be more than 50 kg of roofing material weight.

To ensure that there is no doubt about the strength of the rafter system, it is worth adding 10% to the calculation of the load on the rafter legs.

Table: weight of roofing materials per 1 m²

Number of beams

How many rafters will be needed to arrange the frame of a gable roof is determined by dividing the width of the roof by the pitch between the beams and adding one to the resulting value. It indicates an additional rafter that will need to be placed on the edge of the roof.

Let's say it was decided to leave 60 cm between the rafters, and the length of the roof is 6 m (600 cm). It turns out that 11 rafters are needed (including the additional timber).

Rafter system gable roof- this is a structure made of a certain number of rafters

The pitch of the beams of the supporting roof structure

To determine the distance between the beams of the supporting roof structure, you should pay close attention to such points as:

• weight of roofing materials;
• the length and thickness of the beam - the future rafter leg;
• degree of roof slope;
• level of wind and snow loads.

It is customary to place rafters at 90–100 cm intervals when choosing a lightweight roofing material

A normal step for rafter legs is 60–120 cm. The choice in favor of 60 or 80 cm is made in the case of constructing a roof inclined at 45˚. The same small step should be taken if you want to cover wooden frame roofs heavy materials like ceramic tiles, asbestos cement slate and cement-sand tiles.

Table: rafter pitch depending on length and cross-section

Formulas for calculating the rafter system of a gable roof

Calculation of the rafter system comes down to establishing the pressure on each beam and determining the optimal cross-section.

When calculating the rafter system of a gable roof, proceed as follows:

1. Using the formula Qr=AxQ they find out what the load on linear meter each rafter leg. Qr is the distributed load per linear meter of a rafter leg, expressed in kg/m, A is the distance between the rafters in meters, and Q is the total load in kg/m².
2. Proceed to determining the minimum cross-section of the rafter beam. To do this, study the data from the table included in GOST 24454–80 “Lumber coniferous species. Dimensions".
3. Based on standard parameters, choose the section width. And the section height is calculated using the formula H ≥ 8.6 Lmax sqrt(Qr/(BRbend)), if the roof slope is α< 30°, или формулу H ≥ 9,5·Lmax·sqrt(Qr/(B·Rизг)), когда уклон крыши α >30°. H is the section height in cm, Lmax is the working section of the rafter leg maximum length in meters, Qr - distributed load per linear meter of rafter leg in kg/m, B - section width cm, Rbend - bending resistance of wood, kg/cm². If the material is made from pine or spruce, then Ri can be equal to 140 kg/cm² (grade 1 wood), 130 kg/cm² (grade 2) or 85 kg/cm² (grade 3). Sqrt is the square root.
4. Check whether the deflection value complies with the standards. It should not be greater than the figure obtained by dividing L by 200. L refers to the length of the working section. Correspondence of the deflection value to the ratio L/200 is feasible only if the inequality 3.125·Qr·(Lmax)³/(B·H³) ≤ 1 is true. Qr denotes the distributed load per linear meter of the rafter leg (kg/m), Lmax is the working section of the rafter leg maximum length (m), B is the section width (cm), and H is the section height (cm).
5. When the above inequality is violated, the indicators B and H increase.

Table: nominal dimensions of thickness and width of lumber (mm)

Example of load-bearing structure calculation

Let us assume that α (roof inclination angle) = 36°, A (distance between rafters) = 0.8 m, and Lmax (working section of the rafter leg of maximum length) = 2.8 m. First grade pine material is used as beams , which means that Rben = 140 kg/cm².

Cement-sand tiles were chosen to cover the roof, and therefore the weight of the roof is 50 kg/m². Total load (Q) experienced by each square meter, equal to 303 kg/m². And for the construction of the rafter system, beams 5 cm thick are used.

The following computational steps follow from this:

1. Qr=A·Q= 0.8·303=242 kg/m - distributed load per linear meter of rafter beam.
2. H ≥ 9.5·Lmax·sqrt(Qr/B·Rben).
3. H ≥ 9.5 2.8 sqrt(242/5 140).
4. 3.125·Qr·(Lmax)³/B·H³ ≤ 1.
5. 3.125·242·(2.8)³ / 5·(17.5)³= 0.61.
6. H ≥ (approximate height of the rafter section).

In the table standard sizes you need to find a cross-sectional height of the rafters that is close to 15.6 cm. A suitable parameter is 17.5 cm (with a section width of 5 cm).

This value is quite consistent with the deflection in regulatory documents, and this is proven by the inequality 3.125·Qr·(Lmax)³/B·H³ ≤ 1. Substituting the values ​​(3.125·242·(2.8)³ / 5·(17.5)³) into it, we find that 0.61< 1. Можно сделать вывод: сечение пиломатериала выбрано верно.

Video: detailed calculation of the rafter system

Calculating the rafter system of a gable roof is a whole complex of calculations. In order for the beams to cope with the task assigned to them, the builder needs to accurately determine the length, quantity and cross-section of the material, find out the load on it and find out what the pitch between the rafters should be.

When designing a private house, it is necessary to take into account many various parameters. If they are calculated incorrectly, then the strength of the structure will be in great doubt. The same applies to the roof of the house. Here, even before the start of construction, you need to find out the height of the ridge, the roof area and much more, including calculating the length of the rafters. And how to make the final calculations will be discussed in this article.

What type of roof

How to calculate the length of the rafters? This question will be of interest to everyone who builds a house on their own. But to answer it, you should first find out many other parameters. First of all, you should decide on the type of roof, because the length of the slope and rafters will depend on this. The most common option is considered gable design. But here there are several options, namely:

1. Symmetrical - this is the most common type gable roof. Its popularity is due to its simplicity of design and simple calculation of all necessary parameters. Another plus is the uniform distribution of loads on the rafter system. But there are also disadvantages. Not good rational use areas. This is especially important if you are getting ready. A large number of sharp corners creates many “dead” zones, which cannot be used rationally.
   
2. Asymmetrical. In this case, the slopes are located at different angles. As a result, it increases rational area. But even here there are some drawbacks. Such a gable roof requires more complex calculations. If done incorrectly, the structure may not withstand loads that are not distributed evenly.
   
3. The broken line is the most efficient design if you want to do attic floor. In this case, the rafter legs will “break” at a certain distance from the ridge. As a result, there will be more free space under the roof, and the entire area will be used more efficiently. In this case, calculating the parameters of the rafters, including their length, will be even more difficult.
   
   

You can consider even more complex designs, for example multi-level ones. Such roofs will look very attractive. But to make calculations, and especially to build a rafter system, in this case, without the help of professionals will be almost impossible. Therefore, in most cases, we are limited to the three above-mentioned gable roof options.

System type

Calculating the length of the gable roof rafters will also depend on the system used. Here experts distinguish the following two main varieties:

1. . This is the simplest option. In this case, the rafter legs rest only on the Mauerlat. Their upper part is simply connected to each other. This system is used if the width of the house is small. In this case, the length of the rafters should not exceed six meters. It is not advisable to use the hanging option with an asymmetrical gable roof.
2. - This is a more durable rafter system. It is used if there is an axial line running through the middle of the house. bearing wall. In this case, supports are installed and ridge run, on which it is attached top part rafter legs.

Can also be used combined option. It is often used in the construction of houses with complex geometry. Here it will be more difficult to calculate the length of the rafters and other system parameters. If you have this option, then it is better to entrust everything to a specialist. In this case there will be less mistakes, which means the roof will last longer and will not cause you problems during operation.


What else to consider

The type of roof and the system used are not all the parameters that will be required in order to calculate the length of the rafters of a gable roof. Before you calculate everything, you need to find out a lot more information, namely:




In addition, when calculating the length of the rafters, you should find out what overhangs should be. Not a single roof can do without this “additional” element. Overhangs play the role of protection, which protects the walls of the house and its foundation from being washed away by water flowing from the roof.

They can be a continuation of the rafters or made as independent elements. In the latter case, boards called “fillies” are attached to the main structure. At their core, they are an extension of the rafters.

What length to choose overhangs is up to the home owners themselves. According to existing building regulations, this parameter should be in the range from 50 to 60 centimeters. You shouldn’t do less, otherwise the walls and foundation may suffer. Sometimes overhangs are made more than one meter. In this case, a small canopy is created along the wall, which can be used for relaxing or storing things.


Making calculations

How is the length of the rafters calculated? If the roof has a symmetrical shape, then calculating this parameter is not difficult. To do this, use the formula of the Pythagorean theorem, namely: C is equal to the square root of A squared plus B squared, where:

• C is the required rafter length;
• A is the height at which the ridge is located (from the base of the roof);
• B is half house width.

Moreover, using this formula you can calculate the length of the rafters only up to. The length of the overhangs is not taken into account here. If they are a continuation of the rafters, then their length must be added to the calculated parameter.

How to make a calculation if the roof is asymmetrical? In this case, the slopes will be different. But even here you can use the Pythagorean theorem. You can calculate the rafters for the roof using the same formula, only first find out the value of parameter “B” (in the first case it equal to half width of the house). If the roof is asymmetrical, then at the design stage you will calculate at what distance from the walls the ridge will be located. It is this value that is taken as the “B” parameter. As a result of the calculation, you will get the length of each of the rafter legs (on the left and right slope). As you can see, there are no problems with calculations here either.

There is another way to calculate rafters. In this case, the slope angle is used. This formula is a little more complicated than the previous one. The length of the rafters (for a gable symmetrical roof) will be equal to the sum of 0.5 and the height from the base of the roof to the ridge divided by the cosine of the slope angle.

Another name for the gable roof type is gable roof.

She has two identical inclined surfaces.The roof frame structure is represented by a rafter system.

In this case, pairs of rafters leaning against each other are united by sheathing. Triangular walls, or tongs in other words, are formed at the ends.

A gable roof is quite simple .

At the same time very important point For installation it is necessary to correctly calculate the required parameters.

The attic rafter system contains the following elements:

• Mauerlat. This element serves as the basis for the entire roof structure and is attached along the perimeter of the walls from above.
• Rafters. Boards of a certain size, which are attached at the required angle and are supported in the mauerlat.
• Horse. These are the designations of the place where the rafters meet at the top.
• Crossbars. They are located in a horizontal plane between the rafters. Serve as a coupling element for the structure.
• Racks. Supports that are placed in a vertical position under the ridge. With their help, the load is transferred to load-bearing walls.
• Strut. Elements located at an angle to the rafters to divert the load.
• Sill. Similar to the Mauerlat, only located on the internal load-bearing floor.
• Fight. A block placed vertically between supports.
• . Structure for roof installation.

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

Field designations in the calculator

Specify roofing material:

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

kg/m2

Enter the roof parameters (photo above):

Base width A (cm)

Base length D (cm)

Lifting height B (cm)

Length of side overhangs C (cm)

Front and rear overhang length E (cm)

Rafters:

Rafter pitch (cm)

Type of wood for rafters (cm)

Working area of ​​the side rafter (optional) (cm)

Lathing calculation:

Sheathing board width (cm)

Sheathing board thickness (cm)

Distance between sheathing boards
F (cm)

Calculation of snow load (pictured below):

Select your region

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

Wind load calculation:

Ia I II III IV V VI VII

Height to the ridge of the building

5 m from 5 m to 10 m from 10 m

Terrain type

Open area Closed area Urban areas

Calculation results

Roof angle: 0 degrees.

The tilt angle is suitable for of this material.

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

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

Roof surface area: 0 m2.

Approximate weight of roofing material: 0 kg.

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

Rafters:

Load on the rafter system: 0 kg/m2.

Rafter length: 0 cm

Number of rafters: 0 pcs.

Lathing:

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

Uniform distance between sheathing boards: 0 cm

Number of sheathing boards standard length 6 meters: 0 pcs.

Volume of sheathing boards: 0 m3.

Approximate weight of sheathing boards: 0 kg.

Snow load region

Description of calculator fields

It is quite simple to make all the calculations before starting work on building a roof. The only thing is what is required is scrupulousness and attentiveness, You should also not forget about checking the data after completing the process.

One of the parameters that cannot be avoided during the calculation process is total area roofs. You should initially understand what this indicator represents in order to better understand the entire calculation process.

There are some general provisions which are recommended to be followed during the calculation process:

1. The first step is to determine the length of each slope. This value is equal to the intermediate distance between the points at the very top (on the ridge) and at the bottom (the cornice).
2. Calculating such a parameter it is necessary to take into account all additional roofing elements, for example, overhang and any kind of structures that add volume.
3. At this stage also the material must be specified, from which the roof will be constructed.
4. No need to consider when calculating the area of ​​ventilation and chimney elements.

ATTENTION!

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

The gable roof truss system calculator will best help you with your calculations.

Calculation of the rafter system of a gable roof: calculator

Calculation of rafter parameters

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

This indicator can vary from 60 to 100 cm.

To calculate the number of rafters you need:

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

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

• Roof height. This value is chosen by everyone individually, depending on the need to equip a living space under the roof. For example, this value will be equal to 2 m.
• The next value is half the width of the house, in this case – 3m.
• The quantity that needs to be known is hypotenuse of the triangle. Having calculated this parameter, starting from the example data, we get 3.6 m.

Important: to the result obtained for the length of the rafters, you should add 50-70 cm, taking into account the cut.

Besides, you should determine what width to choose rafters for installation.

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

For this parameter you need to consider:

Determining the angle of inclination

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

• For The size of the slope angle must be more than 22 degrees. If the angle is smaller, this means water will get into the gaps;
• For this parameter must exceed 14 degrees, otherwise, sheets of material may be torn off like a fan;
• For the angle can be no less than 12 degrees;
• For bitumen shingles this indicator should be no more than 15 degrees. If the angle exceeds this figure, then there is a possibility of the material sliding off the roof during hot weather, because the material is attached to mastic;
• For roll-type materials, variations in the angle value can range from 3 to 25 degrees. This indicator depends on the number of layers of material. A larger number of layers allows you to make the slope angle larger.

It is worth understanding that the larger the slope angle, the more area there is free space under the roof, however, more material is required for such a design, and, accordingly, more costs.

More details about optimal angle tilt you can read.

Important: minimal permissible value The slope angle is 5 degrees.

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

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

Formula: tg β = Hk / (Lobas/2) = 2/3 = 0.667

Determining the angle of the roof

Calculation of loads on the rafter system

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

Types of load:

1. Constant. This type of load is constantly felt by the rafters; it is exerted by the roof structure, material, sheathing, films and other small elements of the system. average value this parameter is 40-45 kg/m2.
2. Variable. This type of load depends on the climate and the area where the building is located, since it is caused by precipitation in a given region.
3. Special. This parameter is relevant if the location of the house is a seismically active zone. But in most cases, additional strength is enough.

Important: best when calculating the strength, make a reserve, for this, 10% is added to the resulting value. It is also worth taking into account the recommendation that 1 m2 should not bear a weight of more than 50 kg.

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

• Find out the snow weight parameter. This indicator mainly varies from 80 to 320 kg/m2;
• Multiply by the coefficient that is necessary to take into account wind pressure and aerodynamic properties. This value is indicated in the SNiP table and is applied individually. Source SNiP 2.01.07-85.
(in this example) that will need to be purchased for construction.

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

• The length of the roof in this example is 10m. To find out this parameter, you need to measure the length of the skate;
• The length of the rafters was calculated and equals 3.6 m (+0.5-0.7 m);
• Based on this, the area of ​​one slope will be equal to 41 m2. General value area – 82 m2, i.e. area of ​​one slope multiplied by 2.

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



Roofing kit

Conclusion

It is best to check all calculations several times to avoid errors. When this painstaking preparatory process will be completed, you can safely begin purchasing material and prepare it in accordance with the received dimensions.

After this, the roof installation process will be simple and quick. And our gable roof calculator will help you with the calculations.

Useful video

Video instructions for using the calculator:

In contact with





All parameters must be specified in millimeters

B- Roof length.

Y- Height.

C— Overhang distance.

X— Roof width.

Y2- Extra height.

X2— Additional width.

This program will help you perform an accurate calculation of building materials for roofing: the number of rafters and sheathing boards, roofing material (roofing felt, glassine), quantity sheet material(metal tiles, slate, nulin or ondulin).
Our online calculator will calculate other useful roof dimensions.

The presented program performs calculations in two versions: type 1 - simple gable roofs, type 2 - gable roofs with 2 side gables.

If the designed roof has only one side gable, then in this case we perform calculations according to type 1, and then according to type 2. Based on the calculation results, you will be able to determine the required volume of materials: roofing, sheet, rafters and sheathing boards.

Otherwise, you will make a mistake in the calculation, since the program takes into account the cutouts for the side fronts when calculating the parameters of the main roof.

Based on the calculation results, you receive the volume and size of the material for one roof slope, and the entire volume and size will be indicated in parentheses.

When calculating the volume and useful sizes additional roof, You receive two parameters in brackets: the volume and size of one or two additional roofs.

Important! It is worth considering that the program performs calculations over the entire roof area when determining the number of sheets of roofing material.

For example, it takes 7.7 sheets per row, and only 2.8 rows. Based on the calculation results, you will receive 3 real building rows.

If you want to get the exact number of sheets for the future roof, you need to reduce their height until you get a whole number of rows.

Don't forget to set the exact length of the overlap.

Important! In type 2 mode, when calculating the volume of material for the rafters of the main roof, the program does not take into account the cutouts for the side gables. This calculation of the gable roof truss system is related to the design of the program itself.

You can also use the remaining building material for the rafters to build or repair a house, otherwise you can make corrections to the calculations.

An accurate calculation of the approximate cost of a roof depends on correct basic measurements.

Important! Don’t forget to purchase building materials with a 5-10% reserve for waste.

DIY gable roof

First of all, we need a diagram (drawing or design) of a gable roof, according to which we will make all the calculations (indicated above).

The procedure for constructing a roof is quite simple, but the sequence of certain steps must be followed.

Before installing beams or transfers for the future floor, you need to determine whether the attic will be built or just attic space. As a rule, for a simple attic it is enough to choose a 150x150 mm board. If you are planning to build an attic, then it is best to choose a beam with the same size. To increase the strength of the frame, beams or boards should be mounted exclusively on the walls.

The process of fixing the beams is carried out taking into account the release from the outer edge of approximately 400 mm to prevent precipitation or wind from getting under the roof.

We will use a board cut to 50X150 mm when arranging the attic frame, and fixation is carried out with roofing nails. To give the gable roof stability, it is necessary to carry out all measurements correctly, trying to eliminate errors.

Now let's move on to assembly truss structure, starting the installation from the gables, using the method already described above. At the same time, we saw off the lower parts of the boards, which will give our rafter structure additional stability.

When the structure is fully erected for gable roof, we begin to cover with roofing materials.

Advantages of a gable roof:

• This design is quite simple to construct, which allows you to do all the work yourself without the expensive help of specialists;
• The building materials used are affordable;
• The large angle of inclination of the roof perfectly drains water during precipitation;
• Absence complex structures and kinks, greatly facilitate the construction and cladding of the roof.

A simple online calculator will accurately calculate the length of the rafters, the length of the overhang of the rafters, and the cutting angle of the rafters. Start calculating rafters right now!

DIY rafter system

This calculator is indispensable for those who decide to make DIY rafters. A smart online calculator will accurately calculate the length to the overhang of the rafters, the length of the overhang, the angle of cut and the distance from the edge of the rafter to the beginning of the cut. Online calculator suitable for calculating the rafters of a gable roof and a single-pitched roof.

The permissible range of roof slope angle is from 20° to 60°; the smaller the angle, the less lumber is needed for the farm, but the greater the angle, the more spacious it will be under the roof of the second floor of the house. If you choose an angle of 30°, then for a building width of 10 m, the elevation of the ridge above the top floor will be 2.5 m. The length of the rafter legs will be 7 meters, of which 6.2 are above the house, and the rest will extend beyond the roof. The minimum overhang size is usually taken to be 50 cm for safety from bad weather. Rafters 7 meters long are considered the maximum permissible for an inclined design to the roof ridge, if the length of the rafters is more than 7 meters, additional reinforcement of the gable roof in the form of beams is required. When calculating rafters for a gable roof the step between individual lags is 80-130 cm. The exact pitch size depends on the weight of the roof, the amount of precipitation and wind load in your region of construction. All rafter blanks must be treated with antiseptic and fire-fighting compounds.