The online gable roof calculator will help you calculate the rafter slope angles, required amount lathing, maximum load on the roof, as well as the materials necessary for the construction of a roof of this type with given dimensions. You can calculate the roof from such popular roofing materials as slate, ondulin, ceramic, cement-sand and bituminous shingles, metal tiles and other materials.
The calculations take into account the parameters given in TKP 45-5.05-146-2009 and SNiP "Loads and Impacts".
A gable roof (also known as a gable or gable roof) is a type of roof that has two sloping ramps that run from the ridge to the outer walls of the building. This is the most common roof type today. This is explained by its practicality, low construction costs, effective protection of premises and aesthetic appearance.
Rafters in the structure gable roof lean on each other, connecting in pairs. On the front side, gable roofs are in the shape of a triangle, such ends are called tongs or gables. Usually, an attic is arranged under such a roof, which is illuminated with the help of small windows on the gables (attic windows).
When entering data into the calculator, be sure to check with additional information marked with the icon.
At the bottom of this page, you can leave feedback, ask your own question to the developers, or suggest an idea for improving this calculator.
Explanation of calculation results
Roof angle
The rafters and roof slope are inclined at this angle. It is understood that a symmetrical gable roof is planned. In addition to calculating the angle, the calculator will inform you how the angle corresponds to the norms for the roofing material you have chosen. If you need to change the angle, then for this you need to change the width of the base or the height of the roof rise, or choose another (lighter) roofing material.
Roof surface area
The total area of the roof (including overhangs of a given length). Determines the amount of roofing and insulation materials that will be needed for the work.
Approximate weight of roofing material
The total weight of the roofing material required to fully cover the roof area.
Number of overlapped rolls of insulation
Total amount insulating material in rolls, which is required to insulate the roof. The calculations are based on rolls 15 meters long and 1 meter wide.
Maximum load on rafter system... The calculations take into account the weight of the entire roofing system, the shape of the roof, as well as the wind and snow loads of the region you specified.
Rafter length
The full length of the rafters from the beginning of the ramp to the ridge of the roof.
Number of rafters
The total number of rafters required to build a roof at a given pitch.
Minimum cross-section of rafters, Weight and Volume of timber for rafters
The table shows the recommended cross-sectional dimensions of the rafters (according to GOST 24454-80 Lumber conifers). To determine compliance, the type of roofing material, the area and shape of the roof structure, as well as the loads exerted on the roof are taken into account. The adjacent columns show the total weight and volume of these rafters for the entire roof.
Number of rows of crate
The total number of battens for the entire roof. To determine the number of rows of crate for one slope, it is enough to divide the resulting value by two.
Uniform distance between battens
Use the value shown here to install the battens evenly and avoid unnecessary overruns.
Number of battens with standard length
To frame the entire roof, you will need the number of planks shown here. The calculations are based on the standard 6-meter board length.
The volume of lathing boards
The volume of the boards in cubic meters will help you calculate the cost of the crate costs.
Approximate weight of crate boards
Estimated total weight of the sheathing boards. The calculations use the average density and moisture values for coniferous wood species.
The crown of the construction of a house is always the roof, and what it will be depends not only on the wishes of the homeowner, but also on how to calculate the angle of inclination of the roof.
Installation rafter legs usually does not cause difficulties if there are the necessary fasteners, however, when checking the angle at which the slopes will be laid, you can make a mistake if you do not know some of the subtleties. For example, a very high roof in an area with strong winds will constantly be subjected to heavy loads and, as a result, will most likely be destroyed. Therefore, in order to avoid this, sometimes it is worth giving preference to a not too spectacular, but stable low roof. There are many such examples, but consider the factors themselves that affect the height of the roof. What can it depend on?
As it has already become clear, before calculating the angle of inclination of the roof, first of all, it is necessary to take into account the climatic features of the region. So, for example, the sharper the gable roof, the worse the snow holds on it and the easier rainwater flows from it. However, we already know what such a steep slope is fraught with in strong winds. In places where the sun is hot, it is better to erect ramps with a minimum slope or do without them altogether, that is, to make a flat roof surface, which receives and transfers heat the more, the larger its area. The latter increases in proportion to the steepness of the slope.
The flatter the roof, the higher the likelihood that strong gusts of wind and rain will drive moisture under the edges. roofing.
Among other things, you should consider how the space under the rafter system will be used - as an attic or as a residential attic. In the first case, the distance to the ridge is less than the average height of a person. In the second case, it is necessary that there is enough comfortable space for movement, that is, the clearance in the center of the room should be at least 2.5 meters and, preferably, at least one and a half meters at the lowest point of the ceiling. A significant effect on the angle of the roof slope can be exerted by the coating material, which can only be laid at a certain degree of steepness of the slope.
The most important thing in any room is its usable area, that is, one that can be used for arranging furniture and movement, as well as for storing things. It is sometimes difficult to use some areas of the space where the lowest point of the ceiling cladding is located. However, such places can just be set aside for storing things by making built-in lockers and cabinets there. Another thing is the free movement zone, its area directly depends on the height of the ridge, and therefore on the angle of the roof.
Let's look at an example. Let's say the width of the house is 9.5 meters. If you want space above your head within 3 meters, at least in the center of the room, then the angle between the slopes should be at least 35 degrees, since already at 30 the height of the ridge will be slightly more than 2.5 meters. However, it should be borne in mind that then the width of the space available for free movement (up to a two-meter ceiling level) will turn out to be slightly more than 3.5 meters. If you adhere to the same height at the lowest points of the inclined ceiling, and at the same time make the roof angle 30 degrees, then the width of the room will be reduced to 2.4 meters. It will be most comfortable in the attic under a roof with an angle of more than 40 degrees, but it should be borne in mind that in such a structure, in comparison with a gentle slope (about 10 degrees), the wind load increases by almost 5 times.
In general, the dependence of the angle of inclination of the roof on the height of the ridge only facilitates the calculations of the rafter system.
Roof angle calculator
Choose any 2 known values, enter them.The rest of the values will be calculated automatically.
However, for calculations, you need to know the basics of geometry well enough. Most often, the cross-section of the roof structure from the side of the gables is a triangle, equilateral, isosceles, or another type. Accordingly, using the simplest formulas, you can calculate the length of any side and the angle adjacent to it, knowing the base and height. In this case, in addition to a measuring tape, we need a Bradis table, since we will have to face tangents.
Typesetting materials also do not tolerate steep slopes, for the simple reason that they can slide under their own weight at the slightest prerequisite for this, such as a stormy gust of wind. However, the angle cannot be made too small, since in this case the mass of the roofing material will unnecessarily load the supporting structures, that is, rafters, lathing and other elements. The optimal angle is considered to be 22 degrees, sufficient so that moisture can flow freely during rain and not be blown out by the wind under the joints.
With regard to corrugated board and metal tiles minimum slope- 12 and 14 degrees, respectively, flat enough for precipitation to flow down from the roof, and at the same time its tightness at the joints is not disturbed. V big side the steepness can increase without restrictions, however, taking into account the fact that big square the roof has a solid mass. Also, one should not forget about the wind load and high windage of roofs with an angle close to 45 degrees. The optimal slope is about 27-30 degrees.
But at soft tiles, which consists of individual pieces material of a typical size, the angle of the roof is related to the density of the sheathing. If the slopes are very gentle, then the distance between the planks should be made as small as possible. This is due to the fact that the snow masses can become an unbearable load for the coating. In the event that the steepness of the slopes is maintained within 30-40 degrees, the lathing step is allowed to be larger, up to 45 centimeters.
An online calculator for calculating a shed roof will help you calculate the optimal slope of the slope, the size and total number of rafters, battens, as well as the amount of materials required for building a roof. The calculator's database contains popular roofing materials: slate, ondulin, cement-sand, ceramic and bituminous tiles, metal tiles. This calculator allows you to calculate the dimensions of both sloped and flat roofs.
The calculations take into account the parameters given in TKP 45-5.05-146-2009 and SNiP "Loads and Impacts".
A pitched roof is the simplest type of roof used in buildings today. Such a roof requires minimal consumption of materials and labor costs, since there is only one slope in it. This type of roof is often found in modern buildings, as a rule, these are outbuildings, sheds, garages and other similar structures. Such a roof can provide for an attic or do without it.
For the construction of this type of roof, they are used different kinds roofing and insulation materials. The angle of inclination for a pitched roof can be anything, however, in most cases, small angles are used, up to a flat roof. The smaller the angle, the more important it is to clear the roof of snow in a timely manner, since the load on the roof increases with a decrease in its slope.
When entering data into the calculator, be sure to check the additional information marked with this icon. You will find more information here.
At the bottom of the page, you can leave feedback, ask your own question to the developers, or suggest an idea for improving the calculator.
Explanation of calculation results
Roof angle
The rafters and roof slope are inclined at this angle. The calculator not only takes into account the angle you specified, but also determines how compatible it is with your chosen roofing material. You can change the angle of inclination of the roof through the width of the base or the height of the roof rise.
Roof surface area
The total area of the roof (including overhangs of a given length). Determines the amount of roofing and insulation materials that will be needed for the work.
Approximate weight of roofing material
The approximate weight of your selected roofing material required to cover the entire roof.
Number of rolls of insulation material
Determines the total amount of insulation material based on a roll length of 15 meters and a width of 1 meter. Calculations are made taking into account 10% overlap.
Maximum load on the rafter system. The calculations take into account the weight of the entire roofing system, the roof structure, as well as the wind and snow loads of the region you specified.
Rafter length
The full length of the rafters from the beginning of the ramp to the ridge of the roof.
Number of rafters
The total number of rafters required to erect a roof with a given pitch.
Minimum cross-section of rafters, Weight and Volume of timber for rafters
The table shows the recommended sizes of rafter cross-sections (according to GOST 24454-80 Softwood lumber), which you can use when building a roof with specified parameters. The calculation is carried out taking into account the specified roofing material, area, angles and regional loads. The adjacent columns display the total weight and volume of these rafters for the entire roof structure.
Number of rows of crate
The total number of battens for a given roof size. We also recommend that you consult with the sellers of the roofing material you have chosen about the required step of fastening this material to the battens. This can adjust the pitch or dimensions of the crate you specify.
Uniform distance between battens
Use this value to evenly install the battens and avoid unnecessary overruns.
Number of battens with a standard length of 6 meters
For the lathing of the entire roof, you will need this number of boards. When calculating, the standard board length is used - 6 meters.
The volume of lathing boards
The required volume of boards for the lathing in cubic meters.
Approximate weight of crate boards
Estimated total weight of the sheathing boards. To calculate the mass, the average density and moisture values for conifers are used.
Every potential homeowner should know how to calculate the angle of the roof. country house or a summer residence, because not only the cost of the roofing material depends on the angle of inclination and construction works, but also the very safety of living. Correct geometry roofing allows you to save on building materials and create a structure that prevents the accumulation of snow caps and ice blocks on the roof, the collapse of which can damage both the structure and households. Therefore, in this article we will provide methods for calculating the optimal angle of inclination of the slope.
V residential buildings there are four main types of roofs that can be used. Single slope option will do an annex or an outbuilding, but does not look at all on the main building. The only real plus of this type is the minimum consumption of roofing material, but there may be problems with safety. Almost all the snow that falls on a flat slope lingers, therefore, such roofs are cleaned by hand, getting out on the slope.
A gable roof does not require the construction of a complex frame
The gable version, built on the basis of two slopes, allows you to create a safe roof from which snow caps of any thickness will come off. In addition, the gable roof looks very presentable and does not require the construction of a complex frame. The hip version and its derivatives are a four-slope structure with a complex frame and a relatively low consumption of roofing material. Not all specialists are able to build such a structure - the abundance of joints (especially in the attic or half-hip version) requires more skill and time to assemble the roof. Indeed, in the event of an error, it will flow, flooding a residential building.
The multi-pliers option is a multi-slope design complex shape... This option will only be built by experienced roofers. A multi-gable roof takes more building material and time, making this the most expensive option possible. Moreover, a complicated form (such a roof has five or more slopes) can both decorate and overload the exterior of the home, creating a feeling of excessive complexity, evocative irritation in people with a delicate architectural taste.
And if you choose according to the ratio of the simplicity of the design and the calculations carried out, the volume of building materials used and the presentable exterior, then the best option there will be a gable roof with two slopes. It is this design that we will consider, trying to understand how to calculate the angle of inclination of the roof for a country house or summer cottage.
Before calculating the optimal roof geometry, you should be familiar with the roof structure to understand the process and the terminology used. This will not take much time, since the option we have chosen consists of 7 original elements:
- 1. Mauerlat - logs at the base of the frame, which are laid on the load-bearing wall.
- 2. The ridge is the upper edge of the roof. In our case, this is not really a detail, but the place where the roof slopes meet.
- 3. Lezhnya - beams under the ridge of the roof, laid on the same level with the Mauerlat.
- 4. Racks - a vertical beam connecting the bed and the ridge girder (beam under the upper edge).
- 5. Rafters - beams supported by the Mauerlat and the ridge girder of the roof.
- 6. Lathing - alternation of longitudinal slats, laid on top of the rafters and forming the basis of the frame for the roof slope.
- 7. Strut - a beam laid at right angles to the rafter and extended to the point of junction of the rack and the bed.
At the base of the frame are logs that are placed on load-bearing walls(mauerlata)
The total number of elements depends on their functional purpose... For example, there is always one bed at the roof, and at least two of the Mauerlat. The number of rafters is always paired and equal to the number of struts. Well, and the number of racks is determined by dividing the sum of the rafters by two. Indeed, there is only one rack for each pair of rafter legs. And now about the most important thing - the roof angles we calculate are formed by the base plane (horizontal) and the rafter line, laid at an angle to the Mauerlat.
Technically, the slope of the roof can be varied from 0 to 90 degrees. In the first case, we will get a flat roof, and in the second - a pitched roof (the second slope should be less than 90 °).
Snow load - important factor for determining the angle of inclination of the roof
The geometry of the roof with two slopes and corners differs from the limit values, but it cannot be any, the possible slope of the rafters is determined under the influence of the following factors:
- Wind and snow load. The correct slope should help save on frame construction. After all, the higher such a load, the more rafters, struts and struts will be needed.
- The type of roofing. Each type of roof structural material imposes a restriction on the minimum and maximum value of the calculated angle.
- The cost of building materials - the lower the slope, the cheaper the construction. After all, if the slope of the roof is zero, then the area of the slope is equal to the dimensions of the roof slab. And with an increase in the slope, the area of the slope also grows. And if you have chosen an expensive building material, then the correct slope will help save on its purchase.
- The dimensions of the structure itself - the height of the ridge should correspond to the distance between the Mauerlats. Otherwise, you will get distorted proportions and violate the aesthetics of the exterior of the house.
Moreover, all the factors mentioned above are interrelated, therefore they are considered only in combination, when the optimal geometry of the roof is calculated. How to do it? We will talk about this below in the text.
The optimal angle of inclination should not lead to an increase in snow and wind loads, distort the exterior of the house and force you to buy more roofing and building material... Therefore, to determine its value, we will consistently move along all the above parameters, choosing optimal size for each of them. Then we will calculate the slope based on the average value and permissible limits for the roofing material.
The most optimal angle of inclination of a gable roof is about 37 degrees
For a wind load, the optimum slope is 0 degrees. In this case, it does not add height to the structure. Therefore all multi-story houses have flat roof... In addition, zero slope results in a minimum slope area. In this case, it is equal to the floor area (ceiling or floor). For snow load, the optimal angle is 60 degrees. Roofs with such angles do not accumulate snow on the slopes, which makes it possible to ignore the snow load as such. As a result, the average slope for snow and wind is 30 degrees ((0 + 60) / 2). This value lies beyond the threshold value (25 degrees), which allows to reduce the calculated snow load by 30 percent and does not increase the wind load.
The optimal exterior gives the ratio of the height of the rack and the distance between the Mauerlat and the bed in the proportions of 3: 4 or 1: 1 (in the case of an exploited roof). That is, the tangent of the slope angle in this case will be equal to 0.75 (3/4) or 1.0 (1/1), which corresponds to angles of 37 and 45 degrees. The average angle for the exterior and wind / snow load is 37.5 degrees ((30 + 45) / 2), which corresponds to the optimal proportion of 3: 4 (the ratio between the height of the ridge and half the width of the building from the side of the pediment).
That is, the optimal slope angle should be as close as possible to 37 degrees. Moreover, in snowy regions, it can be brought closer to 45 or even 50 °, and in the southern regions, it can be reduced to 30 °. After all, the snow and wind load even in middle lane Russia are related in a ratio of 4: 1. On average, about 200-210 kilograms of snow or the equivalent of 35-40 kilograms of wind presses on a square meter of the roof structure. Therefore, counteracting snow in our latitudes will be more relevant.
From the point of view of roofing materials, the angle of 37 ° allows the use of such varieties as two-layer roofing felt (roofing felt), galvanized with seams, tongue-and-groove shingles, and slate when arranging the roof.
As you can see, at this angle, you can pick up material for every taste and wallet. From the position rational use space, this angle is also beneficial in that the attic equipped inside the roof will give at least 4 square meters useful area for each meter of length of the bed, and the area outer cover will fluctuate within 13 m 2 per meter of ridge length. That is, 37 ° will also be beneficial from an economic point of view.
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The process of erecting a roof can stop if you do not think in advance about such things as the angle of inclination of the roof and the roofing material used. Since these two indicators have a direct impact on each other, they should definitely be taken into account on an equal footing. Recall that roofs can have one, two or four slopes. Depending on the type, it is necessary to choose the correct angles of the slopes and materials. In this article, we will talk just about how to calculate the angle of inclination of the roof.
What affects the angle of the roof slope?
The exact angle depends on a number of factors:
- the selected roof material;
- climatic features region;
- the intended purpose of the building.
In the case of a gable roof or more complex design, the choice of angle is influenced not only by the characteristics of the climate, but also by the purpose of using the attic. So, for example, if it is non-residential, that is, it is used to store various things, then there is no need to organize a large height of the under-roof room. Well, if there is a full-fledged attic under the roof, then you cannot do without a high roof with large slope angles.
But what should you pay attention to in the end? On design solution, that is, on the project of the building, on the selected roofing material, on the amount of precipitation and the strength of the winds.
Obviously, for regions with strong winds, it is necessary to erect a roof with small angles - this allows to reduce the load on the rafter system, as well as to avoid the unpleasant effect of "tearing" the roof. The same roof structure will be useful for houses erected in sunny regions with high air temperatures and low rainfall. For regions with pronounced atmospheric phenomena(rain, hail, snowfall), the angle of inclination of the roof should be large - up to 60 degrees. This allows the roof and rafters to be relieved from the load of snow and water. In addition, due to the rapid removal of sediments from the surface, the likelihood of leakage of roofing material at the joints is reduced.
In order to calculate the angle of inclination of the roof, all of the above must be taken into account. As a rule, the slope angles of the slopes within the range of 20-45 degrees are considered optimal. Before, it is worth considering the width of the wall, that is, the distance from the beginning of the slopes, since with an increase in this value, the angle can be significantly reduced, without limiting the attic in height.
Metal roofing
It is well known that metal tiles are much heavier than other materials. That is why it is worth very carefully calculating the bearing capacity of the rafter system. It is especially important to take into account the weight of the material in regions with strong winds. Dynamic loads are extremely Negative influence on the material and supporting structure, this is especially pronounced at large angles of inclination of the roof.
For roofs erected using metal tiles, the average angle of inclination is 22 degrees. According to the observations of professionals, it is this slope that prevents the accumulation and penetration of moisture at the joints, it is good to drain snow and water, and also withstand wind loads. in this case, it should be at least 14 degrees. For soft tiles, this figure is 11 degrees, while such a roof requires the organization of a continuous sheathing.
Roof from corrugated board
This material is very popular. It is lightweight, easy to install and repair. In addition, it is very easy to fix the sheets of corrugated board on the crate. The minimum angle of such a roof is 12 degrees. It is this recommendation that is indicated in the instructions of most material manufacturers.
Roofing made of rolled "soft" materials
Such materials include ondulin, roofing material, membrane coatings. Depending on the number of layers used to cover the roof, the angle of inclination can vary from 2 to 15 degrees. So, for a two-layer roof, the slope is 15 degrees, while three-layer construction allows you to cover flat roof with an angle of inclination of 2-5 degrees.
Membrane coatings can be used for the construction of roofs of absolutely any configuration, regardless of its complexity. So, the angle of inclination of a hipped roof (its individual elements) can be from 2 degrees.
As can be understood from all of the above, the chosen angle of inclination depends on the decision of the owner. But this takes into account the loads on the supporting structure (static and dynamic). It is also important to take into account the type of lathing and its pitch, since these parameters depend precisely on the angle of inclination. For small angles, the pitch of the lathing is on average 35-45 cm.
The angle of inclination of the roof directly affects the consumption of roofing material. So, the larger the angle, the more material will be required to cover the planes.
During the selection of roofing material, you can use following tips:
- with a low slope of the roof (up to 10 degrees), the roof can be covered with gravel and stone chips. In this case, take a layer of gravel equal to 15 mm, and stone chips - 5 mm;
- at more pronounced angles of inclination of the roof, waterproofing with bitumen must be used. For roll materials, among other things, it is necessary to cover with a protective material;
- asbestos cement sheets and corrugated board require mandatory sealing of the seams. In this case, all joints are made double.