How to calculate the roof height correctly is the simplest and most accurate way. Accurate calculation of the height of a gable roof How to determine the height of the ridge of a gable roof

Many beginning builders are often faced with the question of how to determine correct height skate gable roof. Even they understand the importance of this parameter, which directly affects the reliability and strength of the roof. The solution to this problem was well known to the ancient peoples.

What affects the height of the ridge?

There is a direct relationship between the height of the ridge and the angle of the roof slope. With a low ridge, the roof slopes will be flat, and in a snowy winter they can cause serious troubles for the house and its inhabitants. If the ridge is too high, then instead of snow it will fully resist the pressure of the wind, with it the house will look more like a sailboat. In addition, both very low and very high roofs are not very attractive. Who wants to build an ugly new house?

The climatic conditions of our country dictate optimal angle tilt around 40±5 degrees.

About the calculation formula

The height of the ridge of a gable roof is calculated using the simplest geometric formula. In it, the height of the ridge is one leg of a right triangle, and half the length of the base of the pediment is the other leg. The length of the slope represents the hypotenuse. If you remember school geometry, you will find that to find the length of an unknown leg (ridge), you should multiply the length of the second leg (half of the base) by the tangent of the opposite angle (roof slope):

Ridge length = half base * tg roof angle

An example for clarity: with a house width of 5 meters and a roof angle of 40 degrees (its tangent is 0.83), the height of the ridge is equal to 5/2 * 0.83 = 2.075.

A little about the process of installing a roof ridge with two slopes

Installing a ridge, as well as the entire roof, is a labor-intensive and complex task; it cannot be done alone. It starts from the edges; before installation, a thin cord is stretched, with the help of which the strict horizontality of the ridge line is controlled. Connecting elements Use special self-tapping screws equipped with gaskets that do not allow moisture to pass through and protect against corrosion processes.

So, we need to calculate the height of the roof. First of all, choose the type of roof. There are quite a lot of them, for example we will choose the most simple types roofs: single-pitched, gable and hipped. More complex designs are calculated similarly, since each element complex roof and is one of the types listed above simple roofs. Then we determine what the roof slope should be. All types of roofing (except attic) have the same angle of inclination. It ranges from 11 to 70 degrees, but the most acceptable solution for Russian latitudes is an angle of 35-45 degrees. This is due to the fact that flat roofs with an angle of less than 35 degrees in winter they experience a large snow load. With an increase in slope of more than 45 degrees, the roof begins to experience increased wind loads.

Next, let's remember geometry. The height of the skate is a leg in a right triangle, in which the second leg is: for pitched roof– width of the house; for a gable roof - the width of the house divided by 2; for a hip roof - the diagonal of the house divided by 2. Thus, the height of the ridge can be calculated by multiplying the length of the leg known to us by the tangent of the angle of inclination of the roof. The table of tangents can be taken from any geometry textbook, as well as on Internet portals dedicated to construction (where they are proudly called coefficients for calculating the height of the ridge).

For example: we have a house 8 m wide, on which two pitched roof with a slope of 35 degrees. The tangent of 35 degrees is 0.7. The height of the ridge is therefore 8m/2 x 0.7= 2.8m.

Calculation of rafter length and pediment area

In a similar way, you can calculate the length of the rafter leg - it is the hypotenuse in the above-described right triangle. Its length, accordingly, is equal to the length of the known leg, divided by the cosine of the angle of inclination of the roof. For example: in a house 8 m wide with a gable roof with a slope of 35 degrees, the length of the rafter leg (to the point of adjoining the wall and the mauerlat) will be equal to: 8m/2 / cos35 = 8m/2 / 0.819 = 4.88m. We add the length of the roof canopy (0.3-0.5 m) to the resulting value, and we get the required length of the rafter leg.

For single-pitched and gable roofs, knowing the height of the ridge, you can easily calculate the area of the pediment: it is a triangle in which the ridge is the height and the width of the house is the base. Calculation of the area of a triangle (remember again school course geometry) is done as follows: the length of the base is multiplied by the height and divided by 2. Thus, the area of the pediment in the house we are already familiar with will be equal to: 8 x 2.8/2 = 11.2 sq.m.

As you can see, calculating the height of the roof is not difficult!

How to calculate roof height

What is important to know for calculations and the dangers of errors

Types and shapes of modern roofs
Ridge run and slope angles
Roof height calculations different forms
Roof calculation using online resources
What to consider when starting roof calculations

The final stage of building any home (whether it is a spacious main dwelling or a small country house) is the arrangement of the roof. It is this that gives the exterior a presentable and complete appearance. But at the same time it performs very important function– retains heat, creates a cozy, most comfortable and pleasant atmosphere inside. It is this element of any structure that, without exaggeration, is called one of the most important.

What does the height of the structure depend on and what is taken into account when performing pre-installation calculations

It is especially important to know how to calculate the roof height for a house, and to understand exactly how to do it correctly. This is why you need to take some time to study this issue. Inaccuracies made in pre-installation calculations lead to serious problems, which are then too difficult to cope with. Often, to eliminate errors, you have to start roofing work all over again.

For example, if the slopes are made with a small angle of inclination, then winter snowfalls will cause serious damage to such a structure (due to the accumulation of snow, there is a risk that the roof will break). It is logical to assume that you can simply do a high skate and all problems will be solved. But this is not true either, because a roof that is too high is most vulnerable to gusts of wind.

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

The design parameters are largely influenced by a number of other factors, for example, there is a direct dependence on the layer the required insulation or installation of snow guards. The dimensions of the ridge are related to the characteristics of the rafter system, but at the same time they can increase the total area of the roof and the amount of materials required for its arrangement.

Everything described 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 roofing structures?

The type of roof has the most direct impact on the calculation and the formulas used for it, as well as on the amount and, therefore, on the consumption of material that needs to be purchased for roofing.

Today the following structures are most often erected:

single-pitched (it is preferable to use it for outbuildings);
gable (most popular for residential buildings);
hipped. Same great choice for residential buildings. There are a variety of options here: spectacular hipped ones (their characteristic feature is the same size and shape of all slopes) or complex hip ones (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 break allows you to increase the area of the attic.

Ridge and determination of rational slope angles

To calculate different roof shapes, 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 hipped and domed ones.

If the structure is simple, gable, then there is only one, but if it is complex, then there are two or more ridges. During the construction of the roof, the rafter legs rest on the ridge purlins, and based on what roofing material is chosen for the final covering, the base of the ridge is selected.

Knowing how to calculate the height of the roof correctly is necessary to build a reliable and durable structure, as well as to predict preliminary construction costs and plan a budget. When calculating the rational angle of inclination, the material from which it was decided to lay the roof is taken into account: some roofing coverings can be laid at an angle of up to 90 degrees, while others can only be laid at an angle of 15 to 60 degrees.

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

Examples of calculations that are easy to do yourself

Basically, if we are talking about simple designs roof, then you will need very little to calculate the height of the roof: a calculator and several well-known principles from the basics of geometry, which are taught in the school curriculum.

The basic principle of calculation is taken from the rule that the length of one leg in a right triangle will be equal to the length of the other if 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 take the angle 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 selected gable design, then in this case the height of the ridge is also very simple to calculate: 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. For clarity, consider what is described above, how to calculate the height gable roof using the example of a house whose width will be 10 meters . So, for the calculations:

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

The most used today are hipped structures, and to calculate them 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 the length directly ridge girder, and rafter system.

Most complex calculations accompanied by roof installation mansard type, characteristic feature which can be called the presence of two slopes with a break, which from the outside makes it general form as if “broken”. Arrangement sloping roof will increase the functional area of the attic. The calculation of a hip roof is based on the example already discussed above of calculating the height of a gable roof, 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 angle values:

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

To simplify calculations, but at the same time quickly obtain the most accurate result, experts prefer to use the “ golden ratio ", for this, in the drawing the outline of the roof is inscribed in a circle. By resorting to this lucky 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 general appearance of the structure being unaesthetic, inharmonious and simply ugly.

Where to go for help: online resource and consultants

If the roof being built has a complex shape, then it requires more voluminous, lengthy settlements. For calculations, data on the cross-section of the rafters, the pitch between them, and the size of the spans are used truss structure. In addition, the dimensions of roof windows, chimneys, the presence of parapets and overhangs are taken into account; it will 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 turning to assistants who can be found on the Internet. These could 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 performs calculations based on them.

When choosing who to turn to for help, remember that a hip roof is an expensive structure, so it does not tolerate errors and inaccuracies. The correctness of the calculations made must be guaranteed. For beginners, calculating hip, hip and hipped roofs turn out to be quite complex, so it is better to entrust them to a design specialist with experience in this field. You can only do calculations related to single-pitch structures for outbuildings and garages, or simple gables built to cover a small country house.

Calculation of roof parameters is the most important stage,

concerning the construction of the roof. It is its result and accuracy that influences how reliable the structure will be, how long it will last, and whether it will have an attractive and harmonious appearance. There is no need to waste time and effort double-checking the results and making sure they are accurate. This is a guarantee that you will have the most durable home, designed for many years of use and providing comfort, coziness and warmth.

Accurate and correctly calculated data will help avoid extra costs for the purchase of materials, and this is reasonable savings during construction.

The Russian hut is gable. The rafter system for it is quite simple, and this has ensured great popularity of this type of roof. Hip roof(four-slope), for example, is geometrically more complex. It is more difficult to calculate and build, so we will take on the calculation of a symmetrical roof with two slopes.

Its calculation consists of determining the length of the rafters that form pairs. Each of these pairs joins its neighbors roof trusses using lathing. The ends of the roof are triangular gables. The length of the rafters, as well as the height of the roof, will be determined by its angle. How to choose it correctly? This will be determined by the prevailing weather in the area.

Selecting the ridge height

Anyone who has been to the Baltic countries or Scandinavia has noticed that the roofs of the villages there are peaked. This is due to the high amount of precipitation, which, in turn, is explained by the predominance of a marine and temperate climate. Water immediately drains from such a roof, and snow does not linger at all. However, the proximity to forested hills reliably protects these settlements from strong winds, so the large windage of such roofs is not of great importance.

Arab houses had flat roofs because the amount of rainfall in desert areas is minimal. But strong dry winds do occur in such areas.

In the same place where the winds rage middle lane, you can find houses with completely different roofs - almost flat or arched, because the absence 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 sets of rules 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 imagined in the form of a triangle, which in fact is each of its gables. Such a triangle will be obtuse. Divide it along the axis of symmetry into two right triangle. 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 * tan α, where:
α is the roof angle taken from the rule book.

The tangent of this angle can be calculated by engineering calculator or use math tables. The resulting leg b is the height of the roof.

Knowing both sides, 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, overhanging 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 like a canopy over the gables, 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 = 3 * tan 45° = 3 * 1

But even without using this formula, you can guess that with an inclination angle of 45°, our right triangle will turn out to be equilateral. That is, even without tables and a calculator, it will become clear that the height of the roof will be equal to 3 m, that is, half the width of the house.

One of the main elements of the structure is the roof. The viability of the house and the peace of its residents depend on its quality and correctly chosen form.

Any pitched roof consists of several basic elements. These include:

Rafter system;
Lathing;
Roof.

A preliminary calculation when designing a house should help determine required amount materials for its construction. Based on this, a budget (estimate) of expenses is drawn up. It is impossible to calculate the cost of a roof without determining its shape and height.

Types of roofs

IN modern construction Almost all roof shapes existing in architecture are common. Gable and four-slope (hip) species are also widespread.

In addition to them, there are also hip roofs, domed roofs, broken roofs (attic) and complex multi-slope roofs.

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

Roofs gable construction usually mounted on, . The gable roof with an attic also looks original.

The rafter system of such roofs consists of paired parts located at an angle to the horizontal line. A plank or continuous sheathing ensures their stability.

The upper part of gable roofs, the joint rafter legs received the name of the skate. This is the most top part the entire building on which many owners of private houses install decorative.

To determine the roof area and calculate the number of boards for sheathing, 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.

Parameters affecting roof height

The roof is the upper part of the building, so it absorbs all the loads falling on it. IN winter period- this is the accumulation of snow on the roof, during the year - wind exposure, which is greater, the more larger area slopes and the steeper they are located relative to the horizontal.

When designing, you can slightly reduce the influence of weather factors. So, when using smooth roofing materials, such as corrugated sheets or metal tiles, you can significantly reduce the amount of snow that will accumulate. If sufficient, it will slide down without significantly increasing the load on the rafter system and sheathing.

To reduce wind loads, it is advisable to make roofs with a lower slope. But this is fraught with the formation of large snowdrifts, which, when the snow melts, can lead to the collapse of the roof. Therefore, it is necessary to find " golden mean» between increasing and decreasing the angle of roof inclination.

Determining the height of the ridge

The first method is mathematical

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

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

To comply optimal conditions operation of the house in conditions large quantities precipitation and fairly strong winds, the slope angle of the roof slopes is taken in the range of 20° - 45°. The Pythagorean theorem and the Bradis table will help you calculate the height of the ridge of a gable roof based on the specified parameters.

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

Let us give the value of the tangent of angles from 20° to 45° in increments of 5°.

For example, let’s 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 40°. In accordance with the above formula, the leg at our disposal will have a length of 3 meters (6:2=3).

The tangent of an angle of 40° is determined from the table. It is equal to 0.839. We multiply the numbers we know and get:

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

Method two - graphical

Less accurately, without using mathematical formulas and tables, you can determine the height of the ridge by drawing a section of the roof on a small scale. To do this, draw an isosceles triangle and draw a 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, it is possible to obtain an approximate value of the desired quantities.

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

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

Watch a video about building a ridge for a gable roof and installing rafters: