Calculation of a gable roof: area, rafters, height. Calculation of a gable roof: principles for selecting proportions and counting consumables Calculation of the height of a gable roof

Determine the size and only after that purchase the material. In order to make calculations, it is not necessary to contact specialized organizations. In the article we will discuss how to correctly calculate the height of the roof, as well as what affects it.

What affects the height of a skate?

A ridge is a horizontal edge connecting the tops of two roof slopes. Overestimation and underestimation of the height negatively affects the operation of the roof, spoils appearance building. Therefore, when calculating, it is not enough to be guided only by your own taste. Before calculating the height of the skate, it is important to pay attention to various technical conditions.

In the article, we will default to roofs with equal slopes in length and angle of inclination. This will make it easier to determine the height, although all the principles described apply to asymmetrical structures.

According to geometry, one of the slopes will be the hypotenuse, and the distance from the ridge to the base will be the leg.

type of roofing;

Now let's go over each item in more detail.

Roofing

Different materials have their own slope requirements. The calculation of the height of the ridge will depend on this indicator. There are general principles for choosing material depending on the slope angle:

For small piece elements, the slope of the slope should be greater than for long ones. sheet materials. This is due to the fact that when moisture accumulates in the joints, leaks may appear. Therefore, skates for slate roof higher than skates on a metal roof. The fact is that the length of the wave slate is only 1.75 m, and the metal roofing material can occupy the entire length of the slope.
The height of the ridge roof also affects the number of joints. With an underestimation of the angle, the number of joints and overlaps should also decrease. Therefore, large-sheet and roll materials are considered the most reliable options.
Heavy roofing elements are placed on steep slopes. The roofs are made of slate and have a large mass, so they make a steep slope. So, they do not bend the rafter beams.

It is worth remembering that the steeper the slope, the more material will be needed to cover the roof. So, if we take as 100% the need for a slope angle of 7-10 °, then an angle of 45 ° will require 150% overrun, and an angle of 60 ° - all 200%.

The dimensions of the slopes relative to the width of the house will change along with the height of the ridge.

Attic space

There are two types of houses: with and without an attic. Each option has its own conditions for calculating the height of the ridge. If the attic is residential, then 30-40 cm is added to the height of the tallest owner. But it is better to think about the guests by making the ceiling at a height of 2.4 meters. But it is important to remember that this is only the ceiling, not the height of the roof. Here you will need to add another half a meter or more, depending on preferences.

If the attic is non-residential, then the height of the ridge is calculated under the influence of fire safety. One of the points obliges the owners to provide a through passage under the roof with a height of at least 1.6 meters and a width of 1.2 m. With complex truss systems, these dimensions can be reduced by 0.4 m. This space will provide free air exchange and passage for repairs, inspection.

Barren buildings are built in such a way that additional walls are erected over the ceiling of the previous floor. For example, in semi-mansard buildings, the height of the walls is increased by 1.4 meters. In such structures, the height of the roof is measured from the lower edge of the Mauerlat. Such designs are suitable for climatic zones with strong winds. This makes it possible to reduce the slope of the slope.

Non-attic structures are popular in the construction of garages, warehouses and other small residential buildings. Usually they do not provide for an attic floor, thereby saving material and time.

atmospheric phenomena

Climatic conditions directly affect the height of the ridge. Therefore, in different cities there is a "golden" slope slope. Atmospheric factors include the following:

Precipitation. The more snow it rains in your area, the more slope you need to do. Accordingly, the height of the roof also increases. If this condition is neglected, then the likelihood of leaks increases.
Wind. For areas with medium and low winds, there is no difference in the height of the ridge. But so, where strong, gusty winds often blow, usually the roof slope does not exceed 10 °. This imposes certain restrictions on the materials used. Without taking into account the strength of the wind, you risk losing the entire roof structure.
The amount of snow. There is a relationship between the steepness of the slope and the amount of snow. The more it falls in winter, the greater the angle you need to make. The reason is the increased load on the truss system. It is recommended to give preference to slopes with a slope of more than 45 °.

You can determine the features of the region of residence by contacting the local weather service or reference literature. The regulatory documentation SNiP 23-01-99 or SP 20.13330.2011 has weather maps and recommendations for construction.

Ways to calculate the height of the ridge

The calculation of the height of the roof largely depends on your preferences. There are two main ways:

mathematical;
graphic.

Let's deal with the mathematical method of counting. As already mentioned in the first subheading, a gable isosceles roof was taken by default. We have the ability to calculate the required height if we know the slope angle and the distance between the slopes. Now you need a Bradis table and a calculator. In the reference literature we find the value of the tangent of our angle, and then we multiply it by half the length between the slopes. The result is the height of the skate.

Let's consider the calculation on a real example. Suppose that our building has dimensions of 7x10 meters. At the same time, we are in an area with medium winds, and we use metal tiles as roofing. We do not plan to equip the attic, but we will take the slope equal to 20 ° so that rainwater drains without problems.

It turns out that the length of the leg is 7/10 = 3.5 meters. According to the table, the tangent of 20° is 0.839. Now we multiply the resulting numbers: 3.5 * 0.839 \u003d 2.94. So the height of the skate gable roof, from the bottom of the Mauerlat, is 2.94 meters.

The graphical method is suitable for those who have a sheet of paper, a pencil and a ruler with a protractor at hand. All that is needed is to draw the roof in section, observing the scale. To do this, draw a horizontal line, mark the boundaries of the roof base on it. Determine the midpoint and draw a perpendicular. On one side, use a protractor to draw a line at the desired angle. The intersection point will show the height, you just need to measure it with a ruler.

The resulting result will be approximate, you still need to add 2/3 of the thickness to it. rafter leg. Small deviations are acceptable and do not critically affect the operation of the roof. These errors are made up of the need to make ventilation under the metal tile and battens.

In order to mark the desired height in reality, it is enough to determine the middle of the building. Then nail a vertical bar or pole at the desired height. After the calculation has been made, try to transfer it as accurately as possible from paper to a real building. Then the roof will last for many years and will not leak on the rainiest days.

What is important to know for calculations and what are the dangers of errors
Types and forms of modern roofs
Ridge run and slope angles
Calculations of the height of roofs of various shapes
Roof calculation using online resources
What to consider when starting roof calculations

The final stage in the construction of any house (be it a spacious main dwelling or a small country house) is the arrangement of the roof. It is she who gives the exterior a presentable and complete look, but at the same time performs a very important function - it retains heat, creates a cozy, most comfortable and pleasant atmosphere inside. It is this element of any structure, without exaggeration, that is called one of the most important.

What determines the height of the structure and what is taken into account when performing pre-assembly calculations

It is especially important to know how to calculate the height of the roof for a house, and to understand exactly how to do it correctly. That is why you need to take some time to study this issue. Inaccuracies made in pre-wiring calculations lead to serious problems that are too difficult to deal with later. Often, to eliminate errors, you have to start work on arranging the roof again. For example, if the slopes are made with a small angle of inclination, then winter snowfalls will cause serious harm to such a design (due to the accumulation of snow, there is a risk that the roof will break). It is logical to assume that you can just make a high ridge and all problems will be solved, but this is not the case, because a roof that is too high is most vulnerable to gusts of wind.

Thus, when starting to calculate the roof and slope angles, as well as the arrangement of the roof, it must be remembered that its height is significantly influenced by:

the general square of the building;
climatic conditions (as you may have guessed, in regions with snowy winters, sloping roofs are not recommended, which are optimal for warm continents);
material for arranging the roof, as well as battens;
selected form;
height of the main building;
personal preferences and tastes of the owner.

A number of other factors also largely affect the design parameters, for example, there is a direct dependence on the layer of insulation laid or the installation of snow retainers. The dimensions of the ridge are related to the features of the truss system, but at the same time they can increase the total area of \u200b\u200bthe roof and the amount of materials required for its arrangement.

All of the above confirms the fact that the strength of the structure, the durability of its operation, the aesthetics and harmony of the external appearance of the building depend on the size of the roof.

What are the common types of modern roof structures

The type of roof has the most direct influence on the calculation and the formulas used for it, as well as on the amount and, therefore, on the consumption of the material that needs to be purchased for the roof. Today, the following structures are most often erected:

shed (it is preferable to use it for outbuildings);
gable (the most popular for residential buildings);
four-slope. Also a great choice for residential buildings. Various options are provided here: spectacular tented ones (a characteristic feature of which is the same size and shape of all slopes) or complex hips (their feature is the participation of two triangular hips and two slopes with a break (trapezoid shape));
attic (consists of two slopes, but always with a break). This fracture allows you to increase the area of the attic.

Skate and determination of rational slope angles

For calculations of different forms of roofing, such a value as the size of the ridge is used. This name refers to the upper, horizontally located edge of the structure, which was formed at the intersection of two roof slopes (inclined planes).

There is a ridge on all types of roofs, except for hipped and domed ones. If the design is simple gable, then it is one, but if it is complex, then the skates are formed from two or more. During the construction of the roof, the rafter legs rest on the ridge runs, and based on which roofing material is chosen for the final coating, the base of the ridge is also selected.

To know how to calculate the height of the roof of a house correctly is also necessary for the construction of a reliable and solid construction, as well as in order to predict the preliminary costs of construction, and plan the budget. In calculating the rational angle of inclination, the material from which it was decided to lay out the roof is taken into account: some roof coverings can be laid at an angle of up to 90 degrees, while others can only be laid from 15 to 60 degrees.

When choosing which slope of the planes to choose a roof for your home, you need to take into account the functionality, the overall appearance of the resulting structure (after all, you want to get an aesthetic structure) and climatic conditions. As practice shows, for European countries, an angle of 35-40 degrees can be called an ideal solution.

Examples of calculations that are easy to do on your own

In principle, if we are talking about simple roof structures, then it will take quite a bit to calculate the height of the roof: a calculator and a few well-known principles from the basics of geometry, which are still taught in the school curriculum.

We take the basic principle of calculation from the rule that the length of one leg in a right triangle will be equal to the length of the other, if it is multiplied by the tangent of the angle formed with the base.

we measure the width of the building (let's say we have a four-meter house);
we accept the angle value equal to 35 degrees (as the recommended optimal option for European latitudes);
we calculate the tangent, it is obtained for a given angle of 0.7002;
4 meters * 0.7002 = 2.8 meters.

If a gable design is chosen, then in this case it is also very easy to calculate the height of the ridge: the width of the house can be divided by “two”, and then multiplied by the tangent of the angle formed by the slope of the slopes. Consider for clarity the above described how to calculate the height of a gable roof using the example of a house whose width will be 10 meters . So, for calculations:

take an angle equal to 35 degrees;
we calculate the tangent, it turns out 0.7002;
10 meters / 2 * 0.7002 = 3.5 meters.

The most used today are four-pitched structures, and for their calculation you can use the same principle (formula) as for how to calculate the height of the ridge of a gable roof, but only the width of the house is divided not by two, but by four. Plus, doing calculations for hipped roof, it is important to take into account directly the length of the ridge run, as well as the truss system.

The most complex calculations are accompanied by the arrangement of a mansard-type roof, a characteristic feature of which can be called the presence of two slopes with a break, which from the side makes its general appearance as if “broken”. Arrangement of a sloping roof will increase the functional area of the attic. Based on the calculation hip roof the above example of calculating the height of a gable roof is laid down, but do not forget that the roof has not one angle of inclination, but several. Before moving on to settlement operations, you need to decide on them. Practice shows that it is best to choose the following angles:

for the lower - over 40 degrees;
for the rest - less than 40 degrees, but always more than 15.

To simplify the calculations, but at the same time to get the most accurate result quickly, experts prefer to use the “golden section” method; for this, the roof outline is inscribed in a circle in the drawing. By resorting to this successful rule, you can easily solve the question of how to correctly calculate the height of the roof, and most importantly, avoid inaccuracies in the calculation, which in practice will lead to the fact that general form structures will be unaesthetic, inharmonious and simply ugly.

Where to go for help: online resource and consultants

If the roof being erected is of complex shape, then it also requires more voluminous, lengthy calculations. For calculations, data on the cross section of the rafters, the step between them, the size of the spans of the truss structure are used. In addition, the dimensions of the roof windows, chimneys, the presence of parapets and overhangs are taken into account, it will definitely be necessary to analyze the possibility of supports and the endurance of the foundation.

Today, anyone who does not know how to calculate the height of a roof can do this by contacting assistants who can be found on the Internet. These can be specialists who are ready to provide you with such services online, or a special Internet resource called a "calculator", in which case the site visitor enters the requested data and the system makes calculations based on them.

When choosing who to turn to for help, remember that the hip roof is an expensive design, so it does not tolerate mistakes and inaccuracies. The correctness of the calculations performed must be guaranteed. For beginners, the calculations of four-slope, hip and hipped roofs turn out to be quite complicated, so it is better to entrust them to a designer with experience in this field. On your own, you can only deal with calculations relating to single-slope structures for outbuildings and garages, or simple gable structures built to cover a small country house.

The classic roof of a Russian hut is a gable roof. The rafter system for it is quite simple, and this has ensured great popularity for this type of roof. A hip roof (four-pitched), for example, is geometrically more complex. It is more difficult to calculate and build, so let's take on the calculation of a symmetrical roof with two slopes. Its calculation consists in determining the length of the rafters that form pairs. Each of these pairs is attached to the adjacent roof trusses with the help of a crate. The ends of the roof are triangular gables. The length of the rafters, like the height of the roof, will be determined by its angle. How to choose it correctly? This will tell the weather prevailing in the area.

Skate height selection

Those who have been to the Baltic countries or Scandinavia could notice that the roofs of village houses there are pointed. This is due to the high amount of precipitation, which, in turn, is explained by the predominance of the maritime and temperate climate. Water immediately flows from such a roof, and snow does not linger at all. However, the neighborhood with forested hills reliably protects these settlements from strong winds, so the large windage of such roofs is not of great importance. In Arab houses, the roofs were flat, because the amount of precipitation in the desert area is minimal. But strong dry winds do occur in such regions. In the same place where winds rage in the middle lane, you can find houses with completely different roofs - almost flat or arched, because just the lack of windage or good streamlining plays a big role. And if such houses used to be built intuitively, based on the experience of generations, today for different regions of Russia, sets of rules have been created that describe wind and snow loads on the roof. In particular, this is SP20.13330.2011, developed on the basis of SNiP 2.01.07-85* "Loads and Impacts". In the central region of the country, for example, it is recommended to choose the height of the ridge so that the angle of inclination of the slopes is approximately 30–45 °. It is this angle that will make it possible to calculate both the height of the roof ridge and the length of the rafters.

Let's turn to school geometry. Our roof must be presented in the form of a triangle, in fact, which is each of its gables. Such a triangle will be obtuse. We divide it along the axis of symmetry into two right-angled triangles. We received two legs, one of which (a) is known to us - this is half the width of the house. The second leg (b), which is not yet known, is the height of our roof.
b = a * tg α, where:
α - the angle of the roof, taken from the set of rules. The tangent of this angle can be calculated on an engineering calculator or use mathematical tables. The resulting leg b is the height of the roof. Knowing both legs, we can calculate the value of the hypotenuse. This is the approximate length of the rafters. However, since the roof often extends beyond the walls of the house, hanging over them, the length of the rafters can be increased. It all depends on the architecture of a particular building. Knowing the length of the rafters and the length of the roof itself, which in this dimension can also protrude beyond the edges of the house, hanging over the gables with a visor, we can already calculate its area, and therefore the amount of roofing material.

Calculation example

Let's say the house has a width of 6 m. Divide it in half and get 3 m. This is our leg a. The slope angle recommended for building a house in this area is 45 °.
b \u003d 3 * tg 45 ° \u003d 3 * 1 That is, even without tables and a calculator, it will become clear that the height of the roof will be 3 m, that is, half the width of the house.

The height of the roof affects the appearance of the house, the complexity of assembling the truss frame and technical characteristics. Therefore, it is important to pay special attention to sizing and only then purchase material. In order to make calculations, it is not necessary to contact specialized organizations. In the article we will discuss how to correctly calculate the height of the roof, as well as what affects it.

A ridge is a horizontal edge connecting the tops of two roof slopes. Overestimation and underestimation of the height negatively affects the operation of the roof, spoils the appearance of the building. Therefore, when calculating, it is not enough to be guided only by your own taste. Before calculating the height of the skate, it is important to pay attention to various technical conditions.

According to geometry, one of the slopes will be the hypotenuse, and the distance from the ridge to the base will be the leg.

type of roofing;

Now let's go over each item in more detail.

Roofing

For different materials have their own requirements for the steepness of the slope. The calculation of the height of the gable roof ridge will depend on this indicator. There are general principles for choosing material depending on the slope angle:

For small piece elements, the slope of the slope should be greater than for long sheet materials. This is due to the fact that when moisture accumulates in the joints, leaks may appear. Therefore, ridges for a slate roof are higher than ridges for a metal roof. The fact is that the length of the wave slate is only 1.75 m, and the metal roofing material can occupy the entire length of the slope.
The height of the ridge roof also affects the number of joints. With an underestimation of the angle, the number of joints and overlaps should also decrease. Therefore, large-sheet and roll materials are considered the most reliable options.
heavy roofing elements placed on steep slopes. Roofs made of slate and ceramic tiles have a large mass, so they make a steep slope. So, they do not bend the rafter beams.

The dimensions of the slopes relative to the width of the house will change along with the height of the ridge.

Attic space

Barren buildings are built in such a way that additional walls are erected over the ceiling of the previous floor. For example, in semi-mansard buildings, the height of the walls is increased by 1.4 meters. In such structures, the height of the roof is measured from the lower edge of the Mauerlat. Such structures are suitable for climatic zones with strong winds. This makes it possible to reduce the slope of the ramp.

Non-attic structures are popular in the construction of garages, warehouses and other small residential buildings. Usually they do not provide for an attic floor, thereby saving material and time.

atmospheric phenomena

Climatic conditions directly affect the height of the ridge. Therefore, in different cities there is a "golden" slope slope. Atmospheric factors include the following:

Precipitation. The more snow it rains in your area, the more slope you need to do. Accordingly, the height of the roof also increases. If this condition is neglected, then the likelihood of leaks increases.
Wind. For areas with medium and low winds, there is no difference in the height of the ridge. But so, where strong, gusty winds often blow, usually the roof slope does not exceed 10 °. This imposes certain restrictions on the materials used. Without taking into account the strength of the wind, you risk losing the entire roof structure.
The amount of snow. There is a relationship between the steepness of the slope and the amount of snow. The more it falls in winter, the greater the angle you need to make. The reason is the increased load on the truss system. It is recommended to give preference to slopes with a slope of more than 45 °.

Ways to calculate the height of the ridge

The calculation of the height of the roof largely depends on your preferences. There are two main ways:

mathematical;
graphic.

It turns out that the length of the leg is 7/10 = 3.5 meters. According to the table, the tangent of 20° is 0.839. Now we multiply the resulting numbers: 3.5 * 0.839 \u003d 2.94. This means that the height of the gable roof ridge, from the bottom of the Mauerlat, is 2.94 meters.

The resulting result will be approximate, you also need to add 2/3 of the thickness of the rafter leg to it. Small deviations are acceptable and do not critically affect the operation of the roof. These errors are made up of the need to make ventilation under the metal tile and battens.

At the stage of designing a gable roof, it becomes necessary to calculate the amount of roofing material. To do this, find the area of \u200b\u200ba gable roof, taking into account gable and cornice overhangs, superstructures, ventilation, etc. To calculate the area, it becomes necessary to calculate a number of roof parameters. The main parameters include:

roof pitch;
length along the ridge run or cornice overhang (which is one and the same);
slope length;
height from ceiling to ridge.

After determining the slope gable roof you need to calculate the height of the skate. Knowing the height of the ridge, you can use trigonometric expressions to calculate the length of the slope, which is the length of the rafter leg.

Height can be calculated in two ways:

using a right triangle
using a table of ratios of the angle of inclination to percentages.

The height is calculated in the first way using the values of the angle of inclination and half the width of the house. Let's consider an example for clarity. The width of the house is 12 meters, the slope is 40°.

a=c×tg A=6×tg 40°=6×0.84=5.05 m.

To find the tangent of 40 °, the Bradis table was used, as in the example above.

In order not to look for a value in the Bradis table, you can use the engineering calculator that is installed on any operating system!

The second option for determining the height of the ridge is to use the ratio table below.

When finding the area of \u200b\u200ba gable roof, the following points must be taken into account:

The total area will be the sum of the areas of each of the slopes. Therefore, first find the area of one slope and multiply by two;
Rarely, but there are cases when slopes in a gable roof may differ in one or more parameters (sizes). In this case, the calculation of the area of each slope is performed separately. The total area is found by summing the areas of individual slopes;
It should be noted that if the roof slope is an irregular rectangle (that is, at least one of the corners of the quadrilateral is not equal to 90 °), then you should “break” the slope into simpler shapes and find areas for them. When such a situation arises, the slope is divided into a rectangle and a right triangle;
When finding the area, do not take into account chimneys, dormer and dormer windows, ventilation holes;
Gable and cornice overhangs, parapets, firewall walls are taken into account.

where Ldd is the length of the house (9 meters);

Lfs - length value gable overhang(0.6 meters);

Lc - the length of the rafter leg, i.e. slope length (4 meters);

Lks - the length of the cornice overhang (0.4 meters).

S=(9 2×0.6)×(4 0.4)=10.2×4.4=44.9 m2.

S=2×44.9=89.8 m2.

In the case of using a tile or rolled material, the length of the slopes will decrease by 0.6-0.8 meters.

The area of \u200b\u200ba gable roof is calculated in order to find out required amount material to be placed on the roof. The steeper the slope of the roof, the more material will be required to cover it. It is recommended to purchase material with a margin of 8-15%. This overspending is caused by the overlap with which the material is laid. To determine the missing material, you should use the table, which takes into account the slope and determines the material safety factor.

When calculating the area of \u200b\u200ba gable roof, it is necessary to correctly make all measurements and use the roofing calculator on the Internet to check the self-calculation. In addition, if the calculation is done correctly, you will not have to buy additional material.

In modern construction, almost all forms of roofs existing in architecture are common. One-slope and two-slope, as well as four-slope (hip) species are widespread.

In addition to them, there are hipped roofs, and domed, and broken (attic) and complex multi-pitched.

Among the most widely used roofs are gable roofs, which are a simple structure consisting of two inclined slopes and two gables - vertical walls of a triangular shape.

Gable roofs are usually mounted on a garage. garden gazebo. The gable roof with an attic also looks original.

The truss system of such roofs consists of paired parts located at an angle to the horizontal line. Their stability is ensured by a plank or solid crate.

Upper part two pitched roofs, the junction of the rafter legs was called the ridge. This is the uppermost part of the entire building on which many owners of private houses install a decorative weather vane.

To determine the area of \u200b\u200bthe roof and calculate the number of boards for the crate, roofing material and the length of the logs themselves, you need to learn how to calculate the height of the ridge.

You can quickly and accurately calculate a gable roof, including determining the height of the ridge, using an online calculator on the Internet.

To calculate the height of the ridge of a gable roof, it is necessary to present its design in a cross section. It will be an isosceles triangle. Therefore, the height of the skate will be the height of this triangle.

Having built the height (perpendicular to the base of the triangle), we get two right-angled triangles, in which one of the legs will determine the parameter we need. The second leg can be determined by dividing by 2 the total width of the house.

To comply with the optimal operating conditions of the house in conditions of high rainfall and sufficiently strong winds, the slope angle of the roof slopes is taken in the range of 20o - 45o. Calculate the height of the ridge of a gable roof, based on the specified parameters, will help the Pythagorean theorem and the Bradis table.

According to the theorem known to everyone since school years, the length of one leg (ridge height) will be determined as the product of the second leg (half the width of the house) by the tangent of the angle opposite the desired leg (roof slope angle).

We give the value of the tangent of the angles from 20o to 45o with a step of 5o.

For example, we calculate the height of the ridge for a standard wooden house 6x8 meters, located in the middle zone of our country, with a roof slope of 40o. In accordance with the above formula, the leg at our disposal will have a length of 3 meters (6:2 = 3).

Thus, with the specified parameters, the height of the ridge from the house will be 2.517 meters.

Less accurately, without the use of mathematical formulas and tables, you can determine the height of the ridge by making an image of the roof section on a small scale. To do this, draw an isosceles triangle and draw the median, which will also be the height.

The angle at the base of the triangle must be accurately drawn using a protractor. When correcting for the accuracy of mathematical tools, you can get an approximate value of the quantities you are looking for.

Important! After completing the process of mounting the ridge on the roof, it is necessary to cover the ridge run with lightweight side tiles. This is required by the installation of a pitched roof ridge.

Thus, the height of the gable roof ridge is calculated. When planning to use an attic space, it is necessary to determine optimal parameters internal space for the free movement of residents and guests of the house.

Gable roof truss system: device, installation, drawings and diagrams, photos and videos

Calculation of a gable roof: parameters, area and consumption of materials

How to make a gable roof gable with your own hands: device, materials, installation, photo and video

Roof and roof repair

The gable roof is the most popular roofing structure, which is equipped with private residential buildings, baths, garages and other buildings. The construction of a roof of this type - rational solution the issue of protecting the interior from the penetration of precipitation, wind and cold. In the process of designing a gable roof, the calculation of the height of the ridge, the determination of the slope and the area of \u200b\u200bthe slopes take center stage.

You can calculate the height of the ridge and the area of \u200b\u200bthe gable roof and other related parameters without using the calculator program. This requires knowledge of elementary geometric formulas, which, we hope, you have not forgotten since your school days. You can independently calculate the skate with two simple methods:

Mathematical. This method is based on the formula for calculating the length of the leg of a triangle. If you imagine a gable roof in a vertical section, it forms an isosceles triangle. The height of the ridge is the segment that runs from the middle of the base to the top of the triangle (roof). To determine what this distance is, you need to use the formula:
a= b x tanα, where
a is the height of the skate,
c - the distance between the slopes along the eaves,
α - the angle formed by the base of the roof and the slope.
By calculating the height of the ridge, you can calculate the area of \u200b\u200bthe pediment, as well as how much lumber will be needed to sew it up. The calculator program uses a mathematical method to calculate.

The formula for calculating the height of the ridge of a gable roof

Graphic. The graphical method is based on the construction of a scaled drawing that reflects the length and width of the house, as well as the actual slope of the slopes of the gable roof. A frontal projection of the box of the house is drawn on a sheet of paper, then the angle between the base of the roof and the slope is measured using a protractor. The distance from the eaves to the ridge connection is measured with a ruler and translated based on the scale. The graphical method for determining the height of the ridge does not require calculation, but errors occur at least when using it.

Calculation of the length of the rafters and the area of \u200b\u200bthe gable

Depending on the magnitude of the slope of the roof slopes, the peculiarity of its operation depends.

It is customary to distinguish 4 types of roofs:

high, with an angle of 45-60 degrees;
pitched, with a slope of 30 to 45 degrees;
gentle, the slope angle of which is 10-30 degrees;
flat. A slope of 10 degrees or less.

The choice of the value of this parameter is influenced, first of all, by natural factors that are characteristic of the area.

The strongest wind great pressure renders on roofs high.

Because such roofs, due to the large angle of inclination, have a very large area.

A large surface area has a very high windage.

Accordingly, the load on the entire structure of the truss system is very high.

And if you decide to arrange a high roof with a very large slope, then you should take care of a very solid foundation.

However, in areas where strong winds prevail, it is unsafe to arrange and flat roofs.

With this type of roof, increased pressure will be exerted on the lower part of the slope in strong winds.

And if the roof fastening is weakened, the entire structure may fail.

Therefore, in areas where strong winds are frequent, it is recommended to arrange pitched roofs with a slope of 25 - 30 degrees.

If the wind force is small, then the slope of the roof can be 30-45 degrees.

If in the area where the house is being built, during the cold season there is heavy snowfall, then a roof with a large slope angle should be built.

In this case, the high roof is out of competition.

On roofs with a large slope, snow does not linger.

It is for this reason that in all northern countries the roofs on buildings are very high (Sweden, Finland, Norway, etc.).

The smaller the angle of the roof slope, the longer the fallen snow will be on the slopes.

The more weight will affect the entire structure.

If the design of the truss system is made with a large margin of safety, then some layer of snow on the roof is not bad.

It provides a little extra insulation.

However, if the design of the truss system of the structure is not designed for a large load, then there may be big problems.

The strength of the truss system, the higher the angle, the less the load on the frame from snow, the precipitation is removed faster and more efficiently;
The presence of strong winds, the right angle helps to reduce pressure on the roof slope;
The height and dimensions of the attic space. The more volume air cushion attic, the warmer the gable roof will turn out. If you correctly calculate and plan the height of the ridge beam, the attic can be turned into an additional living room.

Important! In addition to the above conditions, it is necessary to take into account the weight of the structure, the longer the rafters and overhangs of a gable roof, the greater its weight, which loads the walls of the house, and the higher the cost of construction.

For areas where the main factor is open space, respectively, strong wind loads, the height of the ridge is most often calculated based on the recommendations of the roofing material manufacturer.

In such conditions, the main factor determining the stability of a gable roof is the wind load. Rainwater and wet snow do not pose a particular threat due to the sweeping effect of horizontal air currents, so there is no need to increase the angle of inclination of the roof structure. Moreover, with a significant height of the ridge, the windage of the gable roof and the pressure on the walls of the building sharply increase.

Experts do not recommend reducing the height of the ridge beam to a minimum. Firstly, it significantly reduces the thermal insulation qualities of a gable roof and reduces the amount of usable space in the attic.

Secondly, the air currents no longer press the roof with a reduced ridge height to the box of the building, but tend to overturn or tear it off the supporting surface. This situation is much worse than the situation with windage, since a gable roof is not designed for excessive internal pressure. Thirdly, certain types of roofing material cannot be laid on roof slopes with an extremely low ridge height.

If a large amount of precipitation in the form of wet snow is recorded on the ground, the height of the gable roof ridge and, accordingly, the steepness of the slopes is calculated according to the following scheme:

The maximum amount of wet snow that has fallen in a given area over the past decades is determined;
Based on the future size of the box at home and financial capabilities, determine maximum size rafters and the load-bearing capacity of the roof frame at a specified snow cover thickness. The number of rafters, the height of the rise and the step are calculated based on the methodology described in SNiP 2.01.85 "Loads and impacts";
If the size of the beam under the rafters turns out to be prohibitively large, it is necessary to increase the height of the ridge, but so that the angle of inclination of the gable roof does not exceed the optimal values for the selected roofing material.

When calculating the load on the rafters, it is assumed that with a ridge height that provides an angle of inclination of more than 60 °, the weight of the snow mass on the surface of a gable roof can be ignored. If the ratio of the height of the ridge above the Mauerlat horizon to the distance between the lower supports of the rafters is less than ¼, the snow pressure on the roof is taken into account in full.

Often, the decision to increase the height of the ridge is made not to reduce the load on the roof, but to increase the usable space of the attic. The benefit of such a modification, at first glance, is obvious. You can increase the amount of usable space and equip, for example, an attic and even a balcony. It is relatively easy to evaluate changes in the shape and size of the under-roof space using the diagram shown in the figure.

Before making a decision, try to calculate the geometry of the consequences of increasing the height of the ridge. Consider, as an example, the change in the characteristics of the height and dimensions of a gable roof for the smallest building with a size of 6x4m and a wall height of 2.5m. A sketch of the roof structure is shown in the figure.

With an optimal height of the ridge above the floor slab of 2 m, the length of the rafter will be 2.9 m. At the same time, the usable space under the gable roof will be only 4x1.8x0.5 m. This is enough for ventilation and roof insulation work. The width of the usable space, if desired, can be increased to 1.5 m. On this area, you can organize a bedroom or a rest room, for which, in fact, the attic is used.

An angle of inclination of 45 ° with a ridge height of 2 m provides optimal structural strength, if you choose the right material and calculate the beam consumption for the construction of rafters, you can get a very moderate cost of the rafter system, primarily due to the absence of struts and struts.

You can try to increase the width of the attic comfort zone from 0.5 m to 1.5 m. In this case, the height of the ridge and the angle of inclination of the gable roof will increase to 3.6 m and 60 °, respectively. The space available for use has increased from 1.5 m to 2.5 m, the comfort zone, or the area within which you can walk without bending down, is 1.5 m, which is consistent with the average attic parameters for a country house.

The length of the rafters has increased from 2.9 m to 4.2 m. It is expected to increase the cost of timber for the gable roof frame by 30% due to the need to install additional power elements - crossbars and struts. If you correctly calculate the loads and the method of fastening, the structure will be as strong as in the previous version.

Even a cursory comparison of the two options, without trying to calculate the exact characteristics, allows us to draw certain conclusions.

The size of the useful area of the attic in the broken version of the roof is larger than that of the gable scheme with an increased height of the ridge by 15%, the amount of timber and roofing materials was spent more by 19% and 7%, respectively. The cost of work for a broken circuit is 30-33% higher. The gable roof construction is 0 higher.

In addition, large air "bags" above the ceiling and in the side walls of the attic of the gable version well insulate and soundproof the room. For a long stay in the attic room, a broken circuit is more suitable due to increased comfort. Whereas for a country house or a bath it is quite possible to use the design of a classic gable roof with an increased height of the ridge beam.

The above comparison is valid only for small-sized gable and broken circuits. As the size of the house increases, the gable version of the roof with an increased height of the ridge beam becomes much more expensive than the cost of a similarly sized broken pattern.

Determining how high the roof ridge should be if there is an attic, you need to calculate two values: the height of the lower segment of the roof and the height of its top, based on the lower tier. The lower tier often has a height of 2.0-2.03 meters.

In addition, you need to take into account the height of the tallest owner of the house, adding 30-40 cm to this indicator, so that it is convenient and safe to move around in the room. The dimensions of the upper part of the sloping roof can be loved, they will be determined by the individual preferences of the owners.

Calculation of a gable roof: area, height and other parameters

lean-to;
gable (gable);
four-slope.

Knowing the slope of the slopes, and using trigonometric tables, you can determine the tangent of any angle. The obtained values are substituted into the formula, and at the output we find out the height of the ridge. Let's take a simple example. There is a house 6 * 9 m. The estimated angle of inclination of the roof is 40 degrees. We divide the width of the house in half and get the value of the leg b, equal to 3 meters. From trigonometric tables we learn that the tangent of an angle of 40 degrees is 0.84. Then the height of the ridge is 3*0.84=2.52 m.

Arab houses had flat roofs because the rainfall in the desert was minimal. But strong dry winds in such parts happen.

In the same place where the winds rage in the middle lane, you can find houses with completely different roofs - almost flat or arched, because the lack of windage or good streamlining plays a big role.

And if earlier such houses were built intuitively, based on the experience of generations, today for different regions Russia has created codes of practice that describe wind and snow loads on the roof. In particular, this is SP20.13330.2011, developed on the basis of SNiP 2.01.07-85* "Loads and Impacts". In the central region of the country, for example, it is recommended to choose the height of the ridge so that the angle of inclination of the slopes is approximately 30–45 °. It is this angle that will make it possible to calculate both the height of the roof ridge and the length of the rafters.

S=2×44.9=89.8 m2.

● The main types of pitched roofs include: single-pitched, double-pitched (aka gable), four-pitched. In private housing construction, a gable roof is one of the most common. This is a fairly simple design - two slopes rest on separate and overlapping pairs (connected to each other by a crate of rafters). From the ends of the roof there are two gables, which include the so-called "dormer windows" that contribute to the illumination of the interior space in the attic.

● When calculating the height of a gable roof, the first step is to determine which slope angle will be the most rational. To do this, it is better to refer to the regulatory documents that regulate this type of construction work: SP 20.13330.2011 Loads and impacts. Updated version of SNiP 2.01.07-85*.

In this set of rules there is a formula for calculating the snow load for roofs with a gable roof and the formula for wind action is given. The permissible angle of inclination of the roof, depending on the climatic and weather conditions of a particular region, may be different. For the central regions of the Russian Federation, the permissible angle of inclination is in the range of 30-45 º.

● After the tilt angle is determined. you can begin to calculate the height of the roof ridge. Let's use simple tricks from practical geometry.

Imagine a roof in the form of a triangle. The required height of the skate will perform the function of the unknown leg A, which will divide the area of the triangle into two more, but already right-angled triangles. Formula for calculating the leg. A \u003d B x tgA. The second leg B is 1/2 the width of the house.

The design of a gable roof is usually carried out along the long side of the building. The tangent of the angle is determined from the table, based on the value of the degree of slope.

Roof pitch, in degrees

We substitute the obtained values \u200b\u200binto the formula: A \u003d B x tg A and we get the desired height of the roof ridge.

The building with dimensions of 6x9 meters, the angle of inclination of the roof is 40 º. We divide the width - 6 m in half: 6. 2 \u003d 3. This is the leg B - its value \u003d 3. According to the table, we determine that tg 40 º \u003d 0.84. To find the optimal height of the ridge, we substitute all the initial values \u200b\u200binto the formula: A \u003d 3 x 0.84 \u003d 2.52. It turned out that the most acceptable ridge height is 2.52 m.

● Simple calculations the desired height of the gable roof when designing a private house will help in the future to avoid serious problems in the operation of one of the main components of the entire structure.

Use of site materials subject to obligatory hyperlink to this resource.

As you can see, calculating the height of the roof is a simple matter!

29.04.2013 at 12:04

Gone are the days when only two types of roofing materials were used for covering: tiles and slate.

There are a lot of roofing materials today!

Each material has its own individual technical characteristics and this must be taken into account when calculating the required value of the angle of inclination.

After all, it may happen that the material you like in terms of its parameters simply does not fit.

There is a concept of the minimum value of this parameter.

For each of the materials, this parameter is different.

And if the angle of inclination obtained as a result of your calculations turns out to be less than the minimum value for the roofing material you have chosen, then you cannot use it for roofing.

In the future, a lot of problems can arise if you violate this rule:

for any piece of stacked roofing materials, such as tiles or slate, the minimum slope is 22 degrees. It is with this value that moisture does not accumulate at the joints and moisture does not seep inside the roof;
the angle of inclination for rolled materials (roofing felt, bicrost, etc.) depends on how many layers you plan to lay. If there are three layers, then the slope can be 2-5 degrees. If there are two layers, then it needs to be increased to 15 degrees;
corrugated board manufacturers recommend that when constructing a roof from this material, arrange a slope angle of 12 degrees. Decking can also be used at lower values, but in this case it is necessary to glue the joints of the sheets with a sealant;
for metal tiles, the value of this parameter is 14;
for ondulin - this is a value of 6 degrees;
minimum slope For soft tiles equals 11 degrees. But at the same time, a prerequisite is a continuous crate;
for membrane roofing there are no strict requirements for the minimum value of this parameter.

It's about the minimum values.

My advice is to stick to these rules.

So that in the middle of winter you do not have to re-roof the entire roof.

If it rains and snows often in the region, then the roof will be optimal, the slope angle of which will be 45 - 60 degrees.

After all, it is necessary to remove the load from water and snow from the roof as soon as possible.

Because the strength of the truss system is not unlimited.

And thanks to the large slope of the roof, rain and snow will descend as quickly as possible.

If in the region where the house is built, there are constantly strong winds, then the roof is treated differently.

With a smaller slope, its windage decreases.

And there is no exorbitant load on the roofing material and rafters.

Also, the roof will not tear off during sudden gusts of wind.

In this case, the optimal angle of the roof slope is 9 - 20 degrees.

Very often in the region there is both snow and wind.

For example, the Orenburg region.

In this case, choose the average value of the angle of inclination.

As a rule, its value is in the range of 20 - 45 degrees.

If you pay attention, most pitched roofs have exactly this meaning.

S=2×44.9=89.8 m2.

The amount of precipitation. The more precipitation falls in the construction region in winter, the higher the roof ridge is located. to get steep slopes, from the surface of which the snow slides off by gravity. For middle lane Russia's recommended slope is 40-50 degrees. To teach this indicator with a house width of 6 m, the skate must be raised at least 2.52 m.

Zoning of Russian regions according to the amount of precipitation in winter

Type of roofing material. The nature of the roof covering surface is reflected in the recommended roof pitch. If the surface is rough, then the angle of the slopes is increased to facilitate the descent snow masses. If the roofing material is nasty, then the slope is chosen in the area of \u200b\u200bthe lower limit of the recommended values, since an increase in this parameter increases the area and weight of the slopes.

To better understand what should be the ratio of the roof to the house, you need to imagine the roof in the form of an equilateral triangle. This implementation is the most common. There are, of course, asymmetrical double-sided roofs, in which the areas of the slopes differ. But since the slopes of opposite sides are often equal, the height of the gable roof ridge is determined in a standard way.

An equilateral triangle is divided into two equal parts. The line from the top of the triangle to its base is the axis of symmetry, and, in our case, the height of the ridge.

Another option for a non-attic room is with space combined with the main box. As a rule, its location is at the same height as the ceiling of the previous floor. Attic lofts are built according to a gable scheme, while the Mauerlat must be laid on walls above 1.4 meters. In the case of a half attic, the height of the ridge starts from the bottom of the Mauerlat.

Another factor affecting how to calculate the height of a gable roof ridge is the type of roofing material used.

To select the appropriate roofing, given the height of the ridge, you can use some rules:

The height of the slope of the pitched plane is the higher, the smaller the piece units of the roof. A large number of joints most often cause moisture to get under the roof, so in such cases it is very important to make the precipitation converge faster.
The lower the slope of your roof, the less butt joints should be present on it. It is best in such situations to cover the roof with large-leaf and roll materials.
The greater the mass of the coating, the steeper the slope of the roof should be. It turns out that the higher the ridge, the less effort is exerted on the rafter system and the ceiling.

Mathematical - in this case, the calculation of the size occurs according to the formula for determining the length of one of the sides of a right triangle.
Graphical - you will need to create a roof diagram to scale.

Calculation of the angle of the roof

The slope of the slopes is determined at the design stage and depends on the choice of roofing, climatic conditions, the type of attic space (cold or attic), the design of the roof itself.

If the house will be built in places with strong wind loads, then they try to make the slope small in order to reduce the load on the roof. In the case of building a house in regions with heavy rainfall, the slope is made significant (up to 60 °) in order to reduce the load from snow, melt and rainwater.

However, there is a need to know the value of the slope angle on the erected roof. In this case, an inclinometer or simple trigonometric formulas are used.

But, most often, a novice builder does not have an inclinometer at hand, and geometry comes to the rescue. Let's take a gable roof and consider its section along the ridge. The resulting section is a shed roof, the shape of which is a right triangle.

The first leg acts as half the width of the house. The second leg is the height from the ridge to the ceiling. The hypotenuse is the length of the slope. Knowing any two parameters, you can easily calculate the slope. Let's give an example for greater clarity and understanding.

where A is the angle of the roof slope;

c - half the width of the house;

b is the length of the rafter leg.

The resulting value is the radian measure of the angle. To convert radians to degrees, we use the Bradis table, which is widely available on the Internet. The desired slope will be 66 °.

How to calculate the height of the roof?

A ridge is a horizontal edge of a gable roof, formed at the junction of the vertices of its inclined planes. Without the slightest doubt, we will attribute the height of the ridge to the most significant parameters that set the proportions of the roof.

Both underestimation and overestimation of it can lead not only to a violation of the architectural picture, but also to problems in operation. The ardent desire of the owner of the house to realize own ideas often runs counter to technical regulations, familiarization with which will help to avoid serious errors.

In order to make the process of studying the value under study easier and more understandable, let's imagine the future roof in the form of an equilateral triangle. This is the most common option. In addition to it, there are asymmetrical gable roofs with slopes that differ in area.

However, the angle of inclination of both structural components is most often equal, therefore the height of the ridge is calculated according to the standard scheme.

For convenience, we divide an equilateral triangle into two symmetrical parts. The line passing from the top of the triangle to its base is the axis of symmetry of the figure presented by us, it is also the leg of the right triangle and the height of the ridge.

There is no point in arguing with climate reality, it is necessary to adapt to its inexorable dictation and adapt. Atmospheric phenomena that affect the choice of ridge height include:

. In areas where the weather conditions are characterized by frequent gusty winds, it is customary to build flat and low-pitched roof structures with an inclination angle of up to 10º. In regions with weak and moderate winds, the height of the ridge can be any.

Precipitation. Precipitation is a potential threat of leaks, due to which they become damp, then the elements of the rafter system and the roofing pie gradually become unusable. From roofs with a steepness of more than 45º, precipitation is removed much faster than from flat structures.

Snow mass. In areas with heavy winter precipitation, the construction of roofs with a slope of more than 45º is recommended in order to optimize the rate of snowfall. from lower and flat roofs snow will need to be cleared more frequently.

The indicated characteristics will be prompted by the local meteorological service. You can independently find them in the collection with rules and tables on building climatology SNiP 23-01-99 or according to the zoning maps given in SP 20.13330.2011.

In the gable roof family, there are attic and non-attic representatives. In the first case, the attic space is separated from the box of the house by a ceiling. They are also called "separate", which confirms the architectural independence of the premises between the roof structure and the ceiling.

Attic representatives are residential and non-residential. The height of the ridge of residential roofs is set by ease of movement. Structures with an exploited attic are built mainly according to a broken pattern. involving the construction of a truss system of two tiers.

The height of the ridge of an exploited attic roof consists of two values: the height of the lower part of the roof and the height of the top of the roof, erected on the lower tier. The height dimension of the lower tier is usually taken from 2.0 to 2.3 m.

It is calculated by adding the growth of the tallest of the future owners and a margin of 30 - 40 cm, necessary for the convenience and safety of movement. The size of the top of the sloping roof is arbitrary, depending on the taste preferences of the owners.

The height of the ridge of non-residential attics is determined by fire regulations. In addition, the size of the attic space should not create obstacles for maintenance. The building code regulations indicate that in the attic there should be a through passage along the entire roof of at least 1.6 m in height and 1.2 m in length. In short sections of a composite structure, the width and height of the through passage can be reduced by 40 cm in both directions.

In the second "non-attic" case, the space under the roof is not separated from the box by a ceiling. It is usually located below: at the level of the ceiling system of the previous floor. Non-attic roofs are called "combined", which just indicates the connection of the space under the roof with part of the space of the foot.

Bright representatives of structures without an attic are of the semi-mansard type. They are raised in the usual way. gable scheme, but the Mauerlat is laid on walls with a height of at least 1.4 m. The height of the ridge of the half attic is measured from the lower edge of the Mauerlat.

The practicality of building a semi-mansard roof in regions with high wind load is difficult to overestimate. Thanks to its construction, the minimum lateral load acts on the roof, and the owners receive a comfortable and very spacious additional floor.

no attic and attic floor build low roof garages. small household buildings, warehouses. Covering in such situations is neither economical nor reasonable in terms of access for maintenance.

We have already represented the gable roof as an equilateral triangle. And the height of the skate was represented by the leg of its rectangular counterpart, obtained by dividing the structure into two symmetrical parts. In our created geometric figure all components are interconnected, including angles and side lengths.

We, as roof designers, are interested in the angle of its slope, because. it is directly dependent on the type and specifications roofing. It will help to determine the optimal height of the designed structure.

There are several rules for selecting roofing material, taking into account the height of the ridge and the steepness of the roof, these are:

The smaller the piece elements of the roof, the greater must be the angle of inclination of the pitched planes. Numerous joints of piece coatings create the prerequisites for the penetration of moisture under the roof, so it is necessary to accelerate the precipitation.
The lower the roof, the fewer joints and seams should be on the floor. The priority for the arrangement of large-sheet and roll roofs.
The heavier the coating, the steeper the roof should be built. The weight of massive elements will be distributed in projection per unit area of the base. As a result, the higher the ridge, the less the load puts pressure on the rafter system and the ceiling.

True, the arrangement of a steep roof with a high ridge will cost more. The construction of a structure with a slope of 45º will take 1.5 times more material than covering a flat roof with a steepness of up to 7 - 10º. And if the slopes are tilted at an angle of 60º, the costs will double.

Usually interval suitable angles slope manufacturers of roofing are indicated in the instructions. The recommendations of the manufacturers should be followed in the name of the long-term service of the structure.

Knowing the recommended angle of inclination, the width of the cornice overhangs and the dimensions of the house box, it is possible to find the height of the ridge in the course of simple geometric constructions. However, in the design of roofs, not only the graphic method is used.

The slope of the slopes is indicated by degrees, percentages or decimal fractions, in the numerator of which the height of the ridge is indicated, in the denominator - half of the overlapped span. All three slope expressions are interrelated, but on a construction site it is more convenient to use the latter option.

There are few who want to postpone the angle of inclination of the ramp with a construction protractor at the facility. Moreover, the process of installing layered rafters, for example, is carried out on an already installed ridge run. Those. you need to know the height of the ridge run ahead of time. This is another one of the good reasons that stimulates interest in calculating the height of the skate.

To the percentage expression of the slope of the roof, there was a general attitude both among the masters and among the home craftsmen. Percentages will only help to confuse. The most acceptable method of displaying the slope is the ratio of the height of the ridge to half the span to be covered. It is most often used on the construction site.

Knowing the height of the ridge, you can not peep every minute in the project documentation. Simply by measuring, the middle of the gable wall is determined. At the point obtained, a bar or pole is nailed strictly vertically. From the upper face of the Mauerlat pre-installed on the wall, the size we are studying is laid upwards. It is guided by the construction of the truss system.

To calculate the height of the ridge of a gable roof, the area of \u200b\u200bplanes and other dimensions of the designed structure, there are a significant number of calculator programs on the network. All calculations are carried out automatically, the speed and simplicity of the procedure pleases. True, it is difficult to check the results of the calculations without a visual representation of the planned roof configuration.

Independent designers will need memories of a school trigonometry course and a desire to build diagrams to scale using a monitor or a regular paper sheet.

To determine the height of the ridge of the roof structure, the following methods are used:

Mathematical. It consists in calculating the size according to the formula for calculating the length of one of the sides of a right triangle.
Graphic. It consists in building a roof scheme on a scale to obtain the height of the ridge.

For the production of mathematical calculations, the formula a \u003d b × tgα is used, where a is the desired height of the ridge; b - half the width of the span; tgα is the slope angle chosen by the owner of the house on the basis of technical regulations and recommendations from the roofing manufacturer.

Graphically, the height of the ridge is determined at the intersection of the axis of symmetry of the roof and the line of the slope, laid out at a given angle from the extreme point of the cornice overhang. Let's take one of good examples graphic construction to get an idea of the process.

Let's note an important nuance. The described methods calculate the rise of the roof, and not the total height of the ridge. The real value depends on the technology of fastening the top of the rafters. In hanging systems, the height of the ridge remains unchanged. Similarly, in layered versions, if the top of the rafter does not protrude above the line of the ridge run.

If the tops of the rafter legs rise above the run, then 2/3 of the thickness of the board or timber used in the construction of the rafter system should be added to the roof rise. It is believed that the depth of the cut reduces the thickness of the material by a third.

Influence of atmospheric phenomena

The climatic factor is the variable that must be taken into account when designing a roof.

Atmospheric phenomena that will affect the height of the roof include:

The strength of the wind. In regions characterized by fairly frequent gusts of wind, it is better to build flat and low-pitched roof structures with a slope of up to 10 degrees. Where the winds are restrained, the skate can be set to any height.
Precipitation. Precipitation is always considered the most likely threat, causing leaks that lead to the gradual destruction of the rafter system and the entire roofing pie. For example, from roofs with a slope of 45 degrees, precipitation descends significantly faster than from more gentle ones.
Snowfall volumes. In regions where heavy winter precipitation falls from year to year, it is best to build a roof with a slope exceeding 45 degrees. In this way, faster snow removal can be achieved, which cannot be said for low-slope roofs, where most of the snow will have to be removed by hand.

All this data can be obtained from the local weather service. Alternatively, you can get them yourself in the literature on building climatology SNiP 23-01-99 or according to the available zoning maps SP 20.13330.2011.

Functions of the ridge joint

The location of the ridge in the rafter system of a gable roof

The main function of the ridge is to be a support for the upper part of the roof rafters. It connects all pairs of rafters together, giving rigidity to the structure, evenly distributing the weight of the roofing material of the gable roof.
Ensuring air circulation. The air gap formed at the site of the ridge equipment protects the truss frame from air stagnation and decay, provides ventilation for all wooden elements, due to which the service life of a gable roof is increased.

Important! In the process of designing the roof, you need to choose and correctly calculate the height of the ridge. If the room located under the roof vault is used as a residential area, then the choice is made based on the desired ceiling height, in other cases, the calculation is performed based on the recommended angle of inclination of the slopes.

The window of the online calculator that calculates the height of the ridge

The easiest way to make calculations is using a special calculator program, by entering the initial data into which you can determine the height of the ridge, the area of \u200b\u200bthe slopes and the roof space.

How to calculate roof height

For correct calculation the height of the roof ridge, and also, so that the height of the roof in relation to the height of the house is chosen correctly, you can use one of the many calculator programs that can be easily found on the Internet. Using them is very simple, the calculation results are fast and accurate.

The only negative is that it is not so easy to check the finished calculation results without the possibility of a visual demonstration of the planned roof structure. In addition, if you accidentally enter the wrong number into such a calculator, then it will be possible to find an error only during construction. Therefore, it will be much better if you check all the numbers and design features even before the calculations so that the minimum error in the future does not cost you significant unplanned costs.

In order to calculate the height of the roof ridge as accurately as possible, you will need knowledge of trigonometry, as well as the ability to build buildings to scale according to the scheme. You can use either a monitor or a simple paper sheet for this.

To start calculating a gable roof, specify the scale of the drawings.

Select the required roof option: 1 - a simple gable roof, 2 - a roof with an adjoining element (the so-called dormer window). Please note that the second option is more difficult and more expensive to implement than the first, and the junction (the so-called valley) is a potentially dangerous place for leaks that requires special attention during installation.

Fill in the dimensions in millimeters (mm):

Y- The height of the roof, the distance from the attic floor to the ridge. Affects the angle of inclination of the roof. If you plan to equip a non-residential attic, you should choose a small height (less material for rafters, waterproofing and roofing will be required), but sufficient for revision and maintenance (at least 1500 mm). If it is necessary to equip a dwelling under a roof arch, to determine its height, it is necessary to focus on the height of the tallest family member plus 400-500 mm (approximately 1900-2500 mm). In any case, the requirements of SP 20.13330.2011 (updated edition of SNiP 2.01.07-85*) must also be taken into account. It should be remembered that on a roof with a small angle of inclination (small height), precipitation may linger, which negatively affects its tightness and durability. However, a high roof becomes more vulnerable to strong wind gusts. The optimal angle of inclination is in the range of 30-45 degrees.

X- The width of the building.

C- The size of the overhang. The overhang protects the walls and foundation of the house from atmospheric precipitation. For one and two-storey houses with drainage system minimum size C- 400 mm (according to SNiP II-26-76 *), without the organization of external water flow, not less than 600 mm. The optimal overhang is approximately 500 mm. Consider the climate features of your region in accordance with SP 131.13330.2012 "Construction Climatology" (Updated version of SNiP 23-01-99*).

B– The length of the roof, taking into account the overhangs beyond the gables.

If you have chosen roof option #2 (with a dormer window), also enter the following values:

Y2– Height of the adjoining triangular element;

X2– Width of the base;

C2- Protrusion, i.e. distance from the base to the edge of the overhang.

Roof building materials:

S1- Rafter width.

S2- Rafter thickness.

C3- Rafter pitch, i.e. distance between adjacent rafters.

S1 And S2- important parameters that determine the reliability of the entire truss system. Rafter section (width S1 and thickness S2) depends on the loads acting on it. The own weight of the rafter system, lathing, roofing cake - these are constant loads; temporary - snow, wind; special - seismic effects, industrial explosions). Also, the choice of the width and thickness of the rafters is influenced by the quality and type of material used (board, timber, glued laminated timber), the length of the rafter leg, the distance between the rafters. Approximate section of the beam and rafter pitch ( C3) for different lengths is given in the table.

Rafter length, mm	Rafter pitch, mm	Rafter section, mm
Up to 3000	1200	80x100
Up to 3000	1800	90x100
Up to 4000	1000	80x160
Up to 4000	1400	80x180
Up to 4000	1800	90x180
Up to 6000	1000	80x200
Up to 6000	1400	100x200

When choosing a section of rafters, it is imperative to take into account the recommendations of SP 64.13330.2011 " Wooden structures» », SNiP II-26-76* «Roofs» and establish the load bearing capacity in accordance with SP 20.13330.2011 «Loads and impacts».

C4– Roof outlet (overhang) from the side of the gables. Optimal value C4 approximately 500 mm.

O1, O2- the width and thickness of the board of the crate stuffed on the rafters. According to SNiP II-26-76 * "Roofs", the lathing is made of bars with a minimum section of 30 × 50 mm.

R– The spacing between the boards of the battens depends on the roofing material used (for example, the spacing of the tile wave). The value of the quantity R recommended by SNiP II-26-76* "Roofs". In particular, the base for the roof of asbestos-cement corrugated sheets - slate of civil buildings with an attic should be a crate of ordinary bars with a section of 60x60 mm. To ensure a tight longitudinal overlap, all odd-numbered lathing bars should have a height of 60 mm, and even-numbered 63 mm. The step of the battens of the crate should be no more than 750 mm. Wood is used for battens conifers in accordance with the requirements of SNiP II-25-80 "Wooden structures".

L1 And L2- The length and, accordingly, the width of a sheet of roofing material depends on its type and production features. Pay attention to the compliance of the parameters declared by the manufacturer with regulatory documents (for example, GOST 30340-95 for slate, GOST R 56688-2015 for ceramic tiles, GOST 24045-2010 - corrugated board).

Approximate values for the length and width of roofing materials for a gable roof are shown in the table.

Type of roofing material	Height L1, mm	Width L2, mm
Decking	1000-1400	800-1200
Slate (GOST 30340-95)	1750	980, 1125, 1130
Ceramic tiles	310, 333, 347	190,190, 208
bituminous tiles	1000	317
metal tile	1120, 1180	1040, 1100
Ruberoid	1000	750, 1005, 1025
Euroslate (Ondulin)	2000	950
Galvanized steel	720-1800	2000, 2500
roofing iron	510-1000	710-2000

L3– Roof sheet overlap in percent. The value of the overlap depends on the type of roofing material, the angle of the roof and are regulated by SP 17.13330.2011 "Roofs" (Updated edition of SNiP II-26-76). The required overlap of the roofing material is often indicated by the manufacturer on the packaging.

The calculator allows you to calculate the dimensions of a gable roof: the length and width of the roof sheet for each slope, and the roof area. The required length and number of rafters and battens for the construction of a gable roof truss system. The volume of lumber for the manufacture of rafters and battens. The number of rows of boards of the crate. Also, the calculator will calculate the gable and the height of the ridge of a gable roof. Calculate the amount of roofing and under-roofing insulating material required for a gable roof (necessary to provide vapor barrier, protect insulation and roofing material from condensate, calculated taking into account 10% overlap). With such data, you can find out the price of building a gable roof, more accurately determine the amount of material needed. Notice what better materials for rafters, battens you can order, the lower your roof costs will be (less rejected wood). It is also advisable to consult a qualified roofer (especially if you have chosen the second roof option with an adjoining element), it is better not to make a mistake than to correct it later.

Properly selected and mounted roof will withstand any weather vagaries and will last for decades. What will be the roof of a country house, and what materials it will consist of, is determined at the design stage. It is better to entrust the technical nuances of design to professionals. Before making the final choice, the future owner needs to get an idea about the features of various types of roofs and (importantly) about the amount that the chosen design and roofing material will cost. At this stage, a roofing calculator will help you calculate the material for a gable roof, or any other - this is a quick way to get a detailed answer.

The calculator will help you estimate the cost of a roof in the early stages of planning Source colourbox.com

Online roof calculator

To find out the approximate cost of a roof, of various types, use the following calculator:

Parameters for calculating roofs and roofing material

Before calculating the roof of the house, the calculator will request certain data. One of them is the type of roof. There are two criteria by which you can determine the type of roof: the angle of the roof and the number of slopes (planes). If the angle of inclination of the roof is zero, the roof is called flat, if it is greater than zero - pitched. Pitched structures, in turn, are divided into types, depending on the number of slopes. In private low-rise construction, several types of roofs are common, including:

Shed. It looks rather modest, but the simplest constructively and the least expensive in construction. It is a plane supported by walls of different heights. shed roof can be seen on a garage, shed, or modern high-tech project. Such constructions are described by a small number of parameters and are calculated on all online calculators.

Common forms of pitched structures Source remokna.in.ua

Gable (gable). The most common, classic version with two rectangular inclined planes connected by a ridge and a centuries-old history. The vertical triangular planes between the slopes are called gables (tongs). In modern private construction, the symmetry of the slopes is an optional condition. They can have a different slope and vary in size (broken lines), which opens up great opportunities in the design of roof structures. A gable roof is ideal for an attic. For calculations on the online calculator, parameters such as the length and width of the slopes, the length of the overhangs and the height of the structure are used.

Hip (four-slope). The main slopes are called hips and look like trapeziums, and the pediments are located not vertically, but at an angle, turning into slopes. The hip system is much more difficult to design and install than the previous ones, but this is offset by increased structural stability. In addition, the hip roof allows you to raise the ceiling for the attic, making it much more comfortable. The calculation of the hip roof on the online calculator has certain subtleties (the base can be square or rectangular) and includes the angle of inclination of the slopes.

Multi-forceps. A complex structure consisting of several tongs (gable elements). The calculation of such a roof is a job for an experienced architect. There are online calculators that calculate the roof area of a three-gable roof, but they give a very approximate calculation result.

The complexity of the rafter system of a multi-gable roof excludes independent planning. Source yandex.ru

Attic. The slope consists of two elements: the lower, steeper, and the upper, gentle. This design allows you to increase the useful area of \u200b\u200bthe room, but in order to calculate it on an online calculator, you will need at least a preliminary drawing and understanding of the structure of the truss system.

Types of roofing materials

The issue of roofing material is also decided at the design stage. His choice is influenced not only by the preferences of the designer, but also by more real factors, including the amount of precipitation and the strength of the wind in the region. The online calculator makes it possible to find out not only the quantity, but also the cost of the selected material. A roof calculator is usually set up to calculate the following materials:

Decking.

metal tile.

Soft (roll) roof.

Rebate coating(steel, aluminum or copper).

Roof tiles. Ceramic (piece), flexible (soft), cement-sand, composite.

Slate(mainly for outbuildings).

Calculator for calculating metal tiles (works with several types of roofs) Source amvita.ru

The main elements of the roof structure

The roof of a country cottage is not only a decorative detail and a visiting card of the building, but also a complex engineering system. It includes a variety of building details, the main of which are the following:

Mauerlat. A beam that fits over load-bearing walls. It is a support for the truss system and transfers the load from the roof to the building.

rafters. Bars or boards located at an angle, the basis of the system. The online calculator allows you to calculate some parameters of the truss system.

Auxiliary elements . Racks, beams, girders and puffs serve to fix the rafters and strengthen the structure.

Skate. The upper edge of the roof, the intersection of the slopes.

crate. Lattice structure on which the roofing material is attached. For some types of roofing, continuous flooring is required. The lathing parameters on the online calculator are calculated quite well, especially for a roof of a simple design.

Main structural elements truss system Source kafmt.ru

On our site you can find contacts of construction companies that offer the service of designing country houses. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

What is calculated on the online calculator: types and possibilities

Even with ready-made drawings in hand, the future owner will not always find time for their careful study and painstaking calculations on paper. Among all the ways to solve the question of how to calculate the roof of a house, the calculator in online mode will become the best option. There are two types of calculators that perform a certain type of calculation:

Standard Roof Calculator

The most common type that allows you to get the basic parameters, from the angle of the rafters to permissible load on the roof. In the calculation of roofing material, as a rule, there are all popular options (all kinds of tiles, slate, ondulin and other materials). Widely presented are calculators for calculating a single and gable and hip roof; there are services for calculating a hipped roof or attic. The online gable or shed roof calculator is designed for simple tasks; more advanced calculation programs must be downloaded and installed on your computer.

Fragment of an online hip roof calculator Source citymang.ru

Construction Calculator

For calculations, complex calculation algorithms are used, as a result, you can get not only tables of numbers, but also a set of detailed drawings, as well as 3D visualization. IN construction calculator, as a rule, you can calculate the roof of any type. In addition to the main parameters, you can find out how much lumber is needed, choose the best insulation and vapor barrier. The drawings will show the layout of the truss system and the battens and will allow you to control the correct angle of inclination and the location of the rafters.

The device of an online calculator for calculating a gable roof

The gable roof truss calculator is an easy-to-use tool that allows you to perform basic structural calculations. The interface of any service has a convenient and intuitive look and looks like a set of empty fields with explanations. For the convenience of visitors, next to the page are placed schematic drawings various types of roofs with parameters applied to them.

Before starting calculations, you should familiarize yourself with the designation of the fields. Source stankotec.ru

The user needs to enter the desired value (size) in each field or select an option from the available ones. When filling out, you should pay attention to the dimension - parameters can be entered in cm or mm. After filling in the fields, you press the calculation key and get the desired result in the form of the following data:

Number of roofing materials. The calculator will allow you to calculate the amount of metal tiles (or other material) for a country house with a gable, hip or other roof.

Calculation of the truss system and roof gable. According to the given wall width and height to the ridge, the service will help determine the length of the rafters and the area of the roof gable.

To calculate the material for the roof of the house, the "gable" program will require you to enter the following values:

Roof dimensions. There are separate fields for entering height, width (on each side) and overhang.

Rafter dimensions. Sets the width and thickness, as well as the distance between the rafters and the distance to the edge of the roof.

Video description

About the calculation of the roof on the construction calculator in the following video:

Lathing parameters. Enter the width and thickness of the boards, the distance between them.

Roofing material parameters. If a roofing sheet is selected, set the height, width and overlap of the sheet.

The result of the calculation will be the following parameters:

Roof size. The height and width of the canvas, the total area.

rafters. Number and length of rafters. The volume of the required material (in cubic meters) is also calculated.

crate. The calculation shows the number of rows of boards, the length of each part and the volume of the boards of the crate.

Roofing material. The area of \u200b\u200bhydro and vapor barrier is calculated. So, if roofing material or glassine is chosen as the roofing material, the calculator shows the required number of rolls (based on the size of the roll), taking into account the overlap.

roofing material. The calculator determines not only the coverage area, but also the weight and the required amount of the selected material.

Calculator for calculating the main elements of a gable roof Source stankotec.ru

Calculation of additional parameters

Many online services calculate additional, no less useful values:

Roof slope. The calculator will determine not only the optimal angle value, but also tell you if it is suitable for the selected roofing material. By changing the height of the lift or the width of the base, it is possible to achieve full compliance with the angle of the material.

Calculation of wind and snow load. For some areas, this load may be the determining factor for choosing the type of roof. You will need to enter additional information into the calculator: construction region, type of terrain, height to the ridge of the building, type of wood for the rafters.

Chimney calculation. For safe operation, it is necessary to determine the height of the chimney relative to the roof ridge. Incorrect design can affect the stable operation of heaters and lead to unplanned financial expenses (if rework is required).

When calculating the chimney, the presence of obstacles near housing is taken into account Source stroim-dom.radiomoon.ru

Limitations in using the online calculator

Roofing calculators offered by Internet resources are an affordable and very fast way to get the necessary information. But like any mechanisms designed for the mass user, such calculators tend to use generalized methods of calculation. Worst of all, the calculation process is hidden from the person who turned to the calculator; it is very difficult to double-check the output information.

The calculator for calculating the roof of a house may contain some (permissible) parameter variations, which, nevertheless, will affect the final result. Among the possible results, which may contain inaccurate (approximate) values, there are:

Determining the total amount of roofing material

The building material is never butt-to-joint, so the surface area of the roof and the area of coverage will always be different. When calculating, the roofing area is standardly increased by 15% - this provides a margin for overlap formation.

Video description

About calculating a gable roof with a free calculator in the following video:

If the roof has a complex structure, the calculation also becomes more complicated, since an experienced designer simultaneously solves the additional problem of minimizing waste. For such purposes, different algorithms are used (with different cumulative errors and with different results), which one is embedded in the calculator is known only to its developers.

It is believed that the calculator helps to save on the purchase of building materials. But when installing a complex-shaped roof, in this case it often turns out that extra (often expensive) materials were purchased. The reverse situation, when there is not enough material and you have to pay for an unplanned purchase and delivery, is no less annoying.

Determination of the slope for the roof

Building codes prescribe minimum slope ratings for each roofing material. They are calculated taking into account the slope of the roof and additional indicators (wind and snow load). Specialists perform calculations in accordance with the norms of SNiP "Loads and Impacts" and additional design standards. It is not possible to check what indicators the roofing calculator uses in its work.

Some calculators take into account additional parameters (the presence of skylights and drainage systems) Source stankotec.ru

Roof calculation: how to avoid mistakes

Calculations can be done in one of the following ways:

Calculate the roof manually. If you have basic knowledge of geometry, do preliminary calculations can also be done manually. To do this, it is enough to stock up on paper, a pencil, an ordinary calculator, and remember that any roof is a set of simple shapes (rectangles and triangles), the calculation of the area of \u200b\u200bwhich is described by the simplest formulas from the school course. The method does not work well if the calculations become more complicated. They take a lot of time and increase the risk of error.

Calculation of the roof to carry out in online service . It should be borne in mind that the values are always averaged; your planned home may require a custom solution.

Check the calculation of the roof with a calculator manually. Online roofing calculators are a convenient way to model a roof structure and find out the required amount of building materials. Calculation simple designs it is easy enough to check, but if you do not have a specialized education, confusion with coefficients and percentages is inevitable. Differing results will cause lengthy rechecks and error checking, as well as distrust of the calculator's abilities (or your own).

Checking the results of the calculation will require time and care. Source transsib6.ru

Professional calculation of the roof. For preliminary calculations in order to determine the materials and construction of the roof, this method is clearly not suitable. But when ordering a turnkey house, the construction company will prepare a full-fledged project, which will indicate all the calculations for the calculations and the estimate. In addition, specialists can make preliminary calculations for you even at the stage of discussing the project.

Conclusion

An online roofing calculator is considered to be a good tool for determining the main parameters of a future roof. But professional builders recommend using it only for a rough estimate of the quantity and cost of building materials. Also, the calculator can become an indispensable tool for comparing the costs of various technologies.