How to calculate the height of the roof - how to correctly calculate the height of the ridge of a gable roof. Roof height in relation to the width of the house and how to calculate the height of the ridge for different types of roofing Calculating the height of a gable roof

Options for calculating the roof ridge area have their own characteristics. You should know the following values:

• The sum of the entire length of the skates;
• Width and length of the structure;
• What is the number of ridges and total length;
• How many stingrays are present and what type are they.

When covering the ridge with soft and flexible materials, use the following formula:

Roof area = (2 x overhang width + length of the entire house) x (2 x overhang width + width of the entire house) / cos (angle slope). With all this, the entire coverage area must be taken into account, and valleys must be calculated separately. Then, the amount of material used will depend on the type of metal tile used.

The structure of a gable roof is almost similar to structures of other pitched types.

To cover the roof use:

• Slate;
• Metal tiles.

Roofing units contain units for ventilation passages of shafts and chimneys that go through the roof covering. The individual method of constructing units and their quality directly depend on the type of roof.

A gable roof consists of the following structures:

• Rafters;
• Lathing;
• Overhangs;
• Mauerlat;
• Thermal insulation;
• Horizontal ribs;
• Waterproofing;
• Racks;
• Endovy.

To calculate a soft roof, take into account:

• Structural elements;
• Calculation of the height of the roof and rafter system;
• Take into account the overhangs of the cornices, overlaps and overlaps of the ridges.

The entire calculation will be exactly the same as for a gable roof, but there are some differences. The main difficulty is that this roof will have more than one angle of inclination, and before starting the calculation, we recommend that you use the “golden ratio” rule, which will allow you to fit the contour of the roof into a circle. This action will help you avoid the most common drawback: if the calculation is done incorrectly, the roof will look very ugly.

Pay special attention to the calculations, because the entire reliability of the structure, its long service life and aesthetic appearance will depend on this. Do the calculations in advance, otherwise you may lose a significant amount of money and waste time redoing all the shortcomings.

The process of selecting the best parameters for a gable roof is always a search for a compromise between the desired shape of the frame, the desire to obtain a beautiful high structure and the requirements for ensuring the strength and stability of the roof. In addition, the size of the gable roof will have to be linked to the weather “tricks” of the local climate and your own financial capabilities.

What determines the height of the ridge of a gable roof?

To get a durable and beautiful design, first of all, you need to choose the optimal angle of inclination of the gable roof. This is a basic parameter; it must be selected based on the following criteria:

• The strength of the rafter system, the higher the angle, the less the load on the frame from snow, the faster and more efficiently precipitation is removed;
• The presence of strong winds and a correctly selected angle helps reduce pressure on the roof slope;
• Height and dimensions of the attic space. The larger the volume of the attic air cushion, the warmer the gable roof will be. 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 loading the walls of the house, and the higher the cost of construction.

At what angle is the optimal ridge height for a gable roof?

Unlike the design process, during actual construction it is quite difficult to work with angular values. To directly determine and accurately set the slope angle, you will need precise measuring equipment. Instead of the angle of inclination of the rafter beams, it is easier to use linear values, for example, the length of the rafters, the size of the span or the height of the ridge. In this case, the desired angle of inclination can be easily calculated using trigonometric formulas by measuring the height of the ridge and the distance between the rafter supports on the mauerlat.

Climatic and technological restrictions on the height of the ridge of a gable roof

For areas where the main factor is open space and, accordingly, 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, this significantly reduces the thermal insulation qualities of a gable roof and reduces the amount of usable space in the attic.

Secondly, a roof with a reduced ridge height is no longer pressed by air flows against the building frame, but tends to be overturned or torn away from the supporting surface. This situation is much worse than the situation with windage, since a gable roof is not designed for excess internal pressure. Thirdly, certain types of roofing material cannot be laid on roof slopes with an extremely low ridge height. If such a situation arises, it is better to seek advice from specialists in a specific type of roofing material, who will help calculate the safety margin and installation method.

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

1. The maximum amount of wet snow that has fallen in a given area over the past tens of years is determined;
2. Based on the future dimensions of the house frame and financial capabilities, the maximum size of the rafters and the load-bearing capacity of the roof frame are determined with the established thickness of the snow cover. The number of rafters, lifting height and pitch are calculated based on the methodology set out in SNiP 2.01.85 “Loads and impacts”;
3. If the size of the timber for 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 the gable roof can be ignored. When the ratio of the height of the ridge above the horizon of the Mauerlat 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. In an intermediate position, when the angle of inclination of the gable roof increases from 20° to 60°, the correction reduction factor changes monotonically from 0.7 to 0.1.

The optimal height of the ridge of a gable roof

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 benefits of such a modification are, at first glance, obvious. You can increase the amount of usable space and arrange, for example, an attic or even a balcony. It is relatively easy to assess changes in the shape and size of the 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. Let us consider, as an example, the change in the characteristics of the height and dimensions of a gable roof for the smallest building measuring 6x4 m and a wall height of 2.5 m. 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 beam will be 2.9 m. At the same time, the useful 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 useful space used can, if desired, be increased to 1.5 m. In this area, you can organize a bedroom or a recreation room, which, in fact, is what the attic is used for.

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

You can try to increase the width of the comfortable zone of the attic 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, is 1.5 m, which is quite consistent with the average parameters of an attic for a country house.

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

Alternative option

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

The size of the usable area of ​​the attic in the broken roof version is larger than that of a gable scheme with an increased ridge height by 15%, the amount of timber and roofing materials consumed is 19% and 7% more, respectively. The cost of work for a broken circuit is 30-33% higher. The gable roof structure is 0.8 m higher, but the center of gravity of the frame is lower than the center of pressure, which allows it to be more stable in strong winds, despite the fact that the angle of the rafters is 60 degrees higher than the angle of the top row of the broken roof.

In addition, large air “bags” above the ceiling and in the side walls of the gable attic well insulate and soundproof the room. For a long stay in the attic, a broken pattern is more suitable due to increased comfort. Whereas for a country house or bathhouse 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, a gable roof with an increased height of the ridge beam becomes significantly more expensive than the cost of a similar-sized broken roof.

Conclusion

It should be noted that the calculation of the required ridge height largely depends on the type of roofing material. The vast majority of roofing materials, from tiles to ondulin, fit perfectly on a slope with an inclination angle of 60°. Due to the fact that the roof slope is a single plane, the laid roof has a significantly higher resistance to any form of precipitation. Broken structures often suffer from rainwater leakage during heavy rain and wind precisely at the fracture line.

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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 the required amount of 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.

In modern construction, almost all roof shapes existing in architecture are common. Single- and double-slope, as well as four-slope (hip) types are 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 of a triangular shape.

Gable roofs are usually mounted on a garage or garden gazebo. 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 junction of the rafter legs, is 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 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, this is the accumulation of snow on the roof; during the year, this is wind exposure, which is greater the larger the area of ​​the 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. With a sufficient angle of inclination, 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 a “golden mean” between increasing and decreasing the angle of the roof.

We draw your attention to

about OSB boards - a material for roofing sheathing.

You may also find this article about ondulin useful.

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 maintain optimal operating conditions for the house in conditions of large amounts of 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 theorem known to everyone since school years, 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 of 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 design of the ridge of a pitched roof.

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

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

ratings, average:

The aesthetic indicators, architectural specifics and technical characteristics of the house depend on the height of the roof ridge. When developing a project, it is extremely important to correctly determine the correct size of the structure. To get an ideal result, we suggest that today you figure out how to calculate the height of the ridge of a gable roof, and which method is best to use in independent calculations.

Guidelines for choosing ridge height

The ridge is the horizontal edge of a gable roof, formed at the junction of the vertices of its inclined planes. Without the slightest doubt, the height of the ridge is considered one of the most significant parameters that determine the proportions of the roof.

Both underestimating and overestimating it can lead not only to disruption of the architectural picture, but also to operational problems. The ardent desire of the home owner to realize his own ideas often runs counter to technical requirements, familiarization with which will help to avoid serious mistakes.

In order to make the process of studying the value being studied simpler and more understandable, let’s imagine the future roof in the shape of an equilateral triangle. This is the most common option. In addition, there are asymmetrical gable roofs with slopes varying 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 will divide the 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 we have presented, it is also the leg of the right triangle and the height of the ridge.

Landmark No. 1: Atmospheric phenomena

It is pointless to argue with climate reality; it is necessary to adapt to its inexorable dictation and adapt. Atmospheric phenomena that influence the choice of ridge height include:

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

Landmark No. 2: Availability of an attic

In the family of gable roofs there are attic and non-attic representatives. In the first case, the attic space is separated from the frame 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 either residential or non-residential. The height of the ridge of residential roofs is determined by the ease of movement. Structures with an usable attic are constructed mainly according to a broken pattern, which involves the construction of a rafter system of two tiers.

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

It is calculated by adding the height of the tallest future owner 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 safety standards. In addition, the size of the attic space should not create barriers to maintenance. The building code regulations indicate that the attic must have 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 complex structures, the width and height of the through passage can be reduced by 40 cm in both directions.

In the second “atticless” case, the space under the roof is not separated from the box by a ceiling. Usually it is located below: at the level of the ceiling system of the previous floor. Attic roofs are called “combined”, which refers to the connection of the space under the roof with part of the space of the foot.

Prominent representatives of structures without an attic are of the semi-attic type. They are erected according to the usual gable scheme, but the mauerlat is laid on walls no less than 1.4 m high. The height of the ridge of a half-slope attic is measured from the bottom edge of the mauerlat.

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

Low roofs for garages, small domestic buildings, and warehouses are constructed without an attic or attic floor. The installation of a ceiling in such situations is neither economical nor reasonable from the point of view of access for maintenance.

Guideline No. 3: Type of roofing

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

As roof designers, we are interested in the angle of its slope, because... it is directly dependent on the type and technical characteristics of the roofing covering. This will help 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 roofing elements, the greater the angle of inclination of the pitched planes. Numerous joints of piece coverings create the prerequisites for moisture to penetrate under the roof, therefore it is necessary to speed up the precipitation.
• The lower the roof, the fewer joints and seams there should be on the covering. Large-sheet and roll roofing is a priority for construction.
• The heavier the covering, 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 load puts pressure on the rafter system and the ceiling.

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

Typically, the range of suitable inclination angles is indicated by roofing manufacturers in the instructions. Manufacturers' recommendations should be followed for the sake of long-term service of the structure.

Knowing the recommended angle of inclination, the width of the eaves overhangs and the dimensions of the house box, you can use simple geometric constructions to find the height of the ridge. However, not only the graphical method is used in roof design.

The slope of the slopes is indicated in degrees, percentages or a decimal fraction, the numerator of which indicates the height of the ridge, 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 last option.

There are few people who want to set the angle of inclination of the slope with a construction protractor on site. Moreover, the process of installing layered rafters, for example, is carried out on an already installed ridge girder. Those. You need to know the height of the ridge girder in advance. This is another good reason that stimulates interest in calculating the height of the ridge.

There is a general attitude towards the percentage expression of roof slope both among craftsmen and among home craftsmen. Percentages will only help to confuse things. The most acceptable method of displaying the slope is the ratio of the height of the ridge to half of the span being covered. It is most often used on a construction site.

Knowing the height of the ridge, you don’t have to look at the design documentation every minute. Simply by measuring, the middle of the gable wall is determined. At the resulting point, a block or pole is nailed strictly vertically. From the top edge of the Mauerlat pre-installed on the wall, the size we are studying is laid upward. They are guided by it when constructing a rafter system.

Methods for determining the height of the ridge

To calculate the height of the ridge of a gable roof, the area of ​​the planes and other dimensions of the designed structure, there are a significant number of calculator programs on the network. All calculations are carried out automatically, I am pleased with the speed and simplicity of the procedure. True, it is difficult to check the results of the calculations without a visual representation of the planned roof configuration. And if you accidentally enter an erroneous number, it will be possible to discover “amazing” sizes only at the construction site. Therefore, it is better to understand the features of construction and calculations in advance, so that a banal flaw does not cause extremely high costs.

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

Mathematical and graphical methods

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

• Mathematical. It consists of calculating the size using the formula for calculating the length of one of the sides of a right triangle.
• Graphic. It consists of constructing a scale diagram of the roof and obtaining the height of the ridge.

To perform mathematical calculations, the formula a= b × tgα is used, where a is the desired height of the ridge; b – half the span width; tgα is the slope angle chosen by the house owner based on technical specifications and recommendations of the roofing manufacturer.

Graphically, the height of the ridge is determined at the intersection of the axis of symmetry of the roof and the slope line laid at a given angle from the extreme point of the eaves overhang. Let's look at one of the illustrative examples of graphical construction to get an idea of ​​the process.

Let us note an important nuance. Using the described methods, the rise of the roof is calculated, and not the total height of the ridge. The actual 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 rafters does not protrude above the line of the ridge girder.

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

The sheathing built over the rafters and the thickness of the roofing are usually neglected in calculations. Minor deviations during roof construction are practically unavoidable; in fact, 5-7 cm of roofing with sheathing has almost no effect on anything.

Practical calculation example

Let us use a specific example to analyze the procedure for calculating the height of the ridge. This is how North American carpenters who specialize in the construction of low-rise frame houses calculate the dimensions of a gable roof. Fundamentally, the process is no different from the actions of craftsmen in other countries.

The example has a purely technological specificity: the attachment point for the lower heels of the rafter legs to the base is attached with a notch. The rafters rest on the ridge board. If this is not taken into account when drawing up the diagram and performing calculations, the slope will change, which is extremely undesirable when choosing the limit value of the slope angle recommended by the coating manufacturer.

The independent constructions are based on the same equilateral triangle, divided into two symmetrical halves. We know the width of the span of the house box and the angle of inclination, because it is selected according to the type of roofing.

The algorithm for calculating the height of the ridge comes down to the following steps:

• Let's build a scaled diagram and plot on it the exact dimensions of the box being equipped. The most convenient and understandable scale is 1: 100, according to which 1 cm is displayed on a scale of 1 m. If working with such a reduction is uncomfortable, you can choose a smaller or larger scale.
• Let's find the middle of the span and draw the axis of symmetry of the roof upward from the resulting point.
• Using a protractor, we plot the slope of the designed roof from the corner of the box. We draw a slope line according to the marked angle.
• The intersection of the axis of symmetry of the roof and the slope line of the slopes, i.e. diagonals, will give us the opportunity to estimate at what height the ridge board will be located.
• We outline schematically the outline of the ridge girder and the support post on which the girder will be laid. Their axis of symmetry must coincide with the axis of symmetry of the roof. You just need to put half the thickness of the ridge board on both sides of the axis and draw arbitrary lines.
• The base line of the triangle, the diagonal and the nearby side face of the ridge girder, together with the post, define the required triangle, the vertical leg of which is the rise of the roof.
• We reduce the rise by 1/3 of the thickness of the board, i.e. to the cutting depth of the lower rafter assembly.
• From the resulting height, we set aside the width of the ridge board and draw out the ridge purlin, then the ridge post.
• We draw out the rafter leg on a scale, not forgetting that it will sag by 1/3 of the width due to the notch. To simplify the work, we draw a straight line parallel to the diagonal at a distance of 2/3 of the thickness of the rafter board.

Simply put, the height of the ridge is the sum of the rise of the roof and 2/3 of the thickness of the rafter board. In practice, there will still not be impeccable accuracy, but the error can be considered insignificant and quite acceptable according to the construction standards for the construction of wooden structures, prescribed in the collection SP 64.13330.2011. Ideally, the processes of compression and crushing of the wooden parts of the system should be taken into account.

Video example of a skate device

The video will introduce you to the option of constructing the ridge of a gable roof, similar to the design described in the example:

A well-designed roof with a correctly calculated ridge height will look great. Its components will not create conditions for leaks and premature wear of the structure. It is not difficult to master the calculation methods we propose.

The height of the roof affects the appearance of the house, the complexity of assembling the rafter frame and technical characteristics. Therefore, it is important to pay special attention to determining the size and only after that 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.

What affects the height of the skate?

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

In this article, we will assume by default 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;
• attic space;
• atmospheric phenomena.

Now let's go through each point in more detail.

Roof covering

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

1. 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 metal roofing material can occupy the entire length of the slope.
2. The height of the ridge roof also affects the number of joints. As the angle decreases, the number of connections and overlaps should also decrease. Therefore, large-sheet and roll materials are considered the most reliable options.
3. Heavy roofing elements are placed on steep slopes. Roofs made of slate and ceramic tiles have a large mass, so they have 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 the need for a slope angle of 7-10° as 100%, then an angle of 45° will require a 150% overrun, and an angle of 60° will require 200%.

The size of the slopes relative to the width of the house will change 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 space 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 meter or more, depending on your preferences.

If the attic space is non-residential, then the height of the ridge is calculated under the influence of fire safety. One of the clauses 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 rafter systems, these dimensions can be reduced by 0.4 m. This space will provide free air exchange and passage for repairs, inspection.

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

Attic structures are popular in the construction of garages, warehouses and other small domestic 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, different cities have their own “golden” slope. Atmospheric phenomena include the following factors:

1. Precipitation. The more snow it rains in your area, the more slope you need to make. The height of the roof increases accordingly. If this condition is neglected, then the likelihood of leaks increases.
2. Wind. For areas with medium and low winds there is no difference in the height of the ridge. But like this, where strong, gusty winds often blow, the roof slope usually 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.
3. 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 larger the angle you need to make. The reason is the increased load on the rafter system. It is recommended to give preference to slopes with a slope greater than 45°.

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

Methods for calculating ridge height

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

• mathematical;
• graphic.

Let's look at the mathematical method of calculation. As already mentioned in the first subtitle, the default is a gable isosceles roof. We have the opportunity to calculate the required height if we know the slope angle and the distance between the slopes. Now you will need a Bradis table and a calculator. In the reference literature we find the value of the tangent of our angle, and then multiply it by half the length between the slopes. The result is the height of the ridge.

Let's look at the calculation using a real example. Let's assume that our building has dimensions of 7x10 meters. At the same time, we are in an area with average winds, and we use metal tiles as roofing. We are not planning 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 = 2.94. This means that the height of the ridge of the gable roof, from the bottom of the mauerlat, is 2.94 meters.

The graphic method is suitable for those who have a sheet of paper, a pencil and a ruler with a protractor on hand. All you need is to draw a sectional view of the roof, keeping to scale. To do this, draw a horizontal line and mark the boundaries of the roof base on it. Determine the middle and draw a perpendicular. Using a protractor, draw a line on one side 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 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 result from the need to provide ventilation under the metal tiles and sheathing.

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

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Last revision: 01/29/2016

When constructing any building, one of the most significant moments is the correct calculation of the height of the roof ridge, as well as its area. If the ridge height is low, a large amount of snow can accumulate on the roof, which will create additional load on the entire structure. On the other hand, with a sufficiently high ridge and a large coverage area, the windage of the roof increases, which can become a problem in strong winds. Therefore, it is important to know how to calculate the height of the roof ridge, preventing its premature destruction.

Features of roof design

When designing any building, it is important to correctly calculate the roof parameters. All possible loads must be taken into account here, as well as the required amount of roofing materials. In this case, one of the main parameters will be the correct slope of the slopes of the structure. In typical gable roofs, the slopes typically range from 12 to 45 degrees. There is a known direct relationship between this angle of inclination and the loads created by the weight of the roof on the entire roof structure of the building.

Note! It is necessary to further strengthen the rafter system, which will entail additional construction costs. If you reduce the slope of the slopes, then the load on all structural elements will increase due to precipitation.

It is equally important to correctly calculate the rafter system. This is caused by the transfer of the total load from the rafter legs to the load-bearing walls of the building. In turn, the rafter legs are determined by the size of their cross-section and length. Such structural elements are selected based on the current loads on the roof, taking into account the angle of the slopes. To ensure the necessary safety margin, experts recommend slightly increasing the results obtained for calculating the thickness of the rafter legs.

Since the roof configuration can be different, the calculation of the necessary parameters will be made depending on certain features. To correctly calculate the height of the roof, you should always take into account the number of slopes and its shape. Neglecting such characteristics will lead to errors in calculations. Without such data, it will be impossible to determine the roof area, as well as calculate the required amount of materials for the roofing. The height of the ridge affects the length and configuration of the rafters.

Main settings

When building their own house, each owner will definitely be faced with calculating the height of the roof level. Before determining such a parameter, it is necessary to consider the following nuances:

• number of stingrays;
• the presence of a residential attic or attic;
• the angle of inclination of the slopes, taking into account possible precipitation;
• selected roofing material.

In this case, one should take into account the simple dependence of the amount of precipitation and the angle of inclination of the slopes. The amount of material required for the roofing can be determined by first calculating the height of the roof. In practice, a slope of 45 degrees implies an increase in the cost of the roof by 1.5 times compared to a flat slope design.

It is believed that the regulatory requirements for the building determine the proportions and height of the roof ridge. Meanwhile, this parameter can be calculated knowing the actual dimensions of the walls of the structure. In this case, the calculation of the height of the ridge can be determined using simple geometric formulas. To do this, you need to know the width of the structure, as well as the angle that determines the slope of the roof slopes.

Calculations

Parameters such as the height of the roof ridge and the angle of inclination of its slope are directly related. In addition, the selected roofing material also affects the angle of the roof. For example, soft tiles can be laid on a roof that has a slope of 11–90 degrees. Ceramic tiles require a slope limit of 60 degrees.

It is also necessary to take into account the aesthetic component, therefore it is necessary to ensure that the height of the roof ridge matches the height of the building. The fact is that an excessively flat or too high roof can negatively affect the appearance of the structure. Taking into account the existing climatic conditions, the most optimal option is considered to be the roof inclination angle, which is 35–45 degrees. A roof with a flatter structure will be subject to increased loads due to precipitation.

If we take the height of the ridge as one of the legs of a right triangle, then the other leg will be half the width of the building. Accordingly, the length of the slope will be considered the hypotenuse. In accordance with the trigonometric formula, the length of a leg in such a triangle will be equal to the length of the second leg multiplied by the value of the tangent of the angle at the base. For example, let’s take a building width of 6 m with a roof slope angle of 40 degrees. Referring to the Bradis trigonometric table, we determine the tangent of an angle of 40 degrees. It will be equal to 0.83. It turns out that half the width of the house - 3 meters - needs to be multiplied by 0.83. As a result, we obtain the height of the roof ridge of such a building, which will be 2.49 m.

No house can be imagined without a roof. This design is necessary, because thanks to it, the entire building is protected from environmental influences, and the correct structure of the roof makes it possible to build an attic or attic.

The roof is exposed to various atmospheric phenomena. If you choose the wrong angle of the slope, and, accordingly, the height, then there is a risk that gusty winds or heavy rainfall can damage the integrity of the structure. At best, you will have to carry out minor repairs, at worst, you will have to rebuild the structure.

When designing the construction of any facility, not a single parameter should be neglected, including the value of the roof height. The following series of arguments will confirm the importance of correctly defining such a parameter:

1. Long service life and reliability. The most important characteristic that interests every home owner. An optimally selected roof height will allow the structure to be resistant to the existing loads exerted by roofing materials and other structures, seasonal loads, such as the mass of snow.
2. Aesthetics of appearance. When building a house, it is important to take care of its appearance. Incorrect parameters used in the design will not allow the house to look complete and aesthetically pleasing.
3. Convenience. Due to the height of the roof, you can build an attic space in the house and adapt it for living or storage, which provides certain amenities and increases the living space of the house.

The highest point of the roof is called the ridge. In other words, this is the junction of the inclined planes of the roof, located in a horizontal plane.

If the height of the roof level is calculated incorrectly and is below or above the required value, then this promises not only an imbalance in the architecture, but also problems during the period of use. The height parameter must correspond to the technological processes.

Atmospheric loads

What does it depend on

A very important parameter that will have to be taken into account in calculations and on which the reliability of the structure depends is the angle of inclination.

There are a number of factors on which this parameter depends, as well as the value of the height of the structure.

Atmospheric phenomena

It is necessary to adapt to such a factor, because it is pointless to resist such phenomena.

Among the atmospheric factors that affect the roof, there are the following:

1. Wind. The angle of the slope is selected depending on the weather conditions inherent in the area in which the house is located. If gusty winds prevail in the region, then the angle is chosen to be no more than 10-20 degrees. In other cases, the wind does not affect the angle of the roof slope.
2. Precipitation. Region that experiences heavy rainfall It is recommended to choose a slope angle greater than 45 degrees. This roof design allows precipitation to drain quickly.
3. Snow mass. Similar to the previous factor, the choice of height depends on the abundance of grazing snowfall in winter. It is advisable to choose a slope angle of 45 degrees or more if snow falls frequently and in large quantities in the region.

All information about the characteristics of the above parameters can be found from SNiP 2301-99.

The need to create an attic

Non-residential buildings are usually built without an attic. and quite light, for example, garages and sheds. For a residential building, it is always necessary to provide an attic space. To use it or not is a personal matter for everyone.

The need to construct an attic space is a factor that affects the value of the roof height based on the comfort of movement around the future room. Namely, there is a need to move around the attic and use it as a residential or storage space.

If the premises are intended to be non-residential, then There are a number of rules for this design:

• fire safety requirements for the house are taken into account when calculating the height of the roof;
• the size of the room should not be an obstacle to maintenance;
• It is necessary to have a through passage, 1.6 m high and 1.2 m long.

Roof type

There are special rules based on which the roof height parameter is determined. regarding the material for its coating:

1. If in roofing material a lot of custom items, then the angle of inclination is selected as large as possible.
2. If the roof is selected low, then joints in the roofing material should be kept to a minimum.
3. For large mass materials, select maximum angle so that the total weight of the material is evenly distributed over the surface.

NOTE!

These parameters should be taken into account together to ensure reliable and long service life of the roof.

Roof height in relation to the width of the house

From this angle, the roof height is determined based Pythagorean theorem. To do this, the cross section of the structure is represented as an equilateral triangle.

The parameter required for calculations is roof angle. The height of the structure is leg of a right triangle.

The calculation is carried out as follows:

1. Necessary determine tangent selected value for the slope angle.
2. Knowing the width of the house, one side adjacent to the corner can be calculated by dividing the value by 2.
3. Next, the existing values ​​​​need to be substituted under the well-known formula a = b * tan a.
4. Using this principle, you can understand the dependence of the height of the ridge on the width of the house. The greater the width of the house, the greater the slope angle.

Ratio of house width to ridge height

Height of the ridge of a gable roof

How to calculate the height of the ridge of a gable roof and not make mistakes? Above is the easiest way to determine the height of the roof for its gable variety. A mathematical formula is used for this. But there is another method of calculation - graphical. Initially, a drawing is made on paper, after which the resulting values ​​are measured.

The principle of this method is to transfer the actual parameters of the roof structure in an exact proportional relationship on a smaller scale.

Despite the fact that the method is considered not as accurate as the mathematical one, it is convenient for many and also allows you to find out the necessary results.

The algorithm of actions is as follows:

1. An isosceles triangle is drawn and is drawn to the meridian - this will be the height of the ridge.
2. It is necessary to draw a triangle starting from the previously selected angle of inclination depending on the individual parameters of the house and its location.
3. In order to accurately draw the angle of the roof, you should use a protractor.
4. After the triangle has been drawn, the resulting meridians are measured, i.e. ridge height.

This method is especially convenient for those who are going to equip the attic for a residential space. In this situation, it is possible to clearly identify and indicate all the necessary parameters.

Height of gable roof

Calculation of the height of a hipped roof

Despite the fact that the hipped roof type is much more complex in design, in the calculations you can use parameters and formulas based on the principle of calculating the height of the gable roof variety.

The hipped roof has two types:

1. Tent. In this design, all roof slopes have the same length, area and are identical in shape. This variety is used in regions with strong winds. It can withstand strong gusty winds and high loads.
2. Hip. The slopes are represented by two triangles and trapezoids. This type requires significant costs for materials for its construction, however, it is ideal for installing an attic floor. However, this design is not suitable for regions where there are strong gusty winds. In such conditions, the structure needs additional strengthening.

In any of the listed types of roofs for calculations it is necessary to find the figure of a right triangle in the design. This will allow you to determine the values ​​you are looking for.

For a hipped roof, the following method is suitable for calculating the height of a gable roof:

1. A right triangle can be found in the design.
2. In the figure found, mark the hypotenuse, which will be the rafters, and the other side – the width of the house, divided by 2.
3. Based on the tilt angle parameter (tg angle), the third side of the figure is calculated, which represents the height.

Hip roof height

Useful video

You can learn how to determine the height and angle of the roof from the video lesson:

Conclusion

Determining the height for your future home yourself is a simple, but responsible task. Considering that this is a fairly important parameter on which the reliability of the entire structure depends, it is better to entrust such work to specialists. Especially if there are doubts about determining the angle of inclination of the slope. Special design programs will also help in this matter.

In contact with

• The construction of a private house is completed by erecting the roof. This is a particularly important stage, since the reliability of the structure depends on the competent execution of this process. The construction process itself can be roughly divided into several stages, starting from installing the Mauerlat to laying the roofing.

  When installing roofing material on slopes, cracks usually form at the point where they converge at the very top of the roof. Therefore, an element is needed that, on the one hand, will protect the under-roof space from the penetration of precipitation and melt water, and on the other hand, will provide roof ventilation. This is the so-called roof ridge (photo below).

  This element is defined as follows. The ridge of the roof of a house is the top edge located horizontally at the junction of the slopes. It also includes those associated with this rib. Thus, this is a prefabricated structure consisting of a collection of several fragments. Installing a ridge on a roof requires a little theoretical training and basic construction skills, that is, in fact, anyone can cope with this task.

  Types of ridge construction

  The ridge on the roof is formed by closing the planes of the slopes. It has two versions and depends on.

  • A beam that is installed on vertical posts supported by tie rods or on ceiling beams, or is fixed to the gables. It serves as a support for the top of the rafters.
  • A purlin (ridge base) laid at the top of rigid triangular trusses exposed one after another from rafter legs connected in pairs, which are interconnected by jumpers. The role of a purlin can be a roof ridge log with a wide cross-section or two 5 cm thick boards sewn at an angle.

  From all this it follows that first of all we are dealing with the component of a gable roof. However, it can also be found in structures with a more complex configuration. For example, or , in which it is displaced.

  Relatively recently, asbestos cement was used to decorate the ridge, but today manufacturers more often offer galvanized roof ridges. The dimensions of galvanized ones are usually standard: their length is approximately two meters, and the width of the shelves is 25-30 cm.

  Depending on the installation location, there are three main options for the ridge:

  • straight, becoming a gable roof. It is installed strictly horizontally;
  • mortise, which are cut into the internal joints of the roof slopes, below the main one;
  • crossed, suitable for installation on multi-slope structures in places where the planes cut into the main roof intersect.

  How to calculate the height of the ridge of a gable roof

  The required value depends on several factors, but, as a rule, the type of attic is considered decisive.

  In the general case, the slope of the slope and the dimensions of the building and, as a derivative, the type of material are taken into account. The calculations use data from a specially designed table, in which the width of the building and the magnitude of the slope are related through a coefficient.

  

  Let’s say the width of the building is 8 m and the slope is 40°. The height of the ridge of a gable roof is calculated according to the following scheme: half the width is multiplied by a coefficient, the value of which is found from the table. Thus, the height or distance between the top point of the roof ridge and the ceiling is 4x 0.86 = 3.44.

  The height of the chimney relative to the roof ridge SNiP

  

  There is an opinion that regarding the ridge of the roof, it is determined solely by the desire of the homeowner and the exterior of the house. However, it is not. In fact, the efficiency of heating equipment, the quality removal of combustion products, and the level of energy consumption depend on it.

  Correct calculation of this parameter is based

  • at the location of the pipe in relation to the ridge;
  • the slope of the slopes;
  • the presence of objects or trees near the house that are higher than it;
  • intensity of wind and snow loads characteristic of a given area.

  Let us present the optimal values ​​of the required value for some structures:

  • Flat roof. Regardless of the cross-section, the height of the pipe should be more than half a meter.
  • Pitched roof. Let L= distance from the ridge strip. At
  • L = 1.50 m, the height of the pipe cannot be 50 cm of the purlin or the enclosing parapet more than 50 cm;
  • 1.5 < L< 3 м, труба предполагается выше этих элементов;
  • L > 3 m, then the parameter is determined along an imaginary line that is 10 ◦ with the horizon line.

  How to make it yourself

  

  The purlin is made of steel or wood. When building private houses, the second option is mainly used, since steel ones are quite heavy.

  • Installation is carried out after completing the main stages of roofing. The basic principle of laying the ridge trim elements is to lay the outer fragments on the side of the gables, through which the mounting cord is pulled. The lace is leveled and temporarily fixed to the opposite gables. It will serve as a guide for the remaining fragments.
  • It is recommended that two people work together. After installing and fastening the first structural element, move on to the next. The fragments are laid with a spacing of about 20 cm, which allows for better waterproofing of the structure. In the same way, all elements are laid and secured along the slope.

  Attention!

  Particular attention should be paid to fastening the outer elements, since they are exposed to maximum wind loads.

  

  • However, adjustment alone, even if the shelf width is more than 20 cm, is not enough to ensure sufficient waterproofing. In any case, there will be gaps through which drops of rain or snow blown by the wind can get under the roof. You can put a layer of glass wool in the groove, but try not to compact it too much, as this may interfere with ventilation.
  • There is another way: instead of glass wool, use self-adhesive foam tape (filler), which is laid along the edge of the shelf from the bottom. But this material is quite expensive, and the result obtained is similar to the option using glass wool.
  • A ventilation compartment must be provided. Otherwise, condensation cannot be avoided, even if the roof has been reliably protected from moisture.

  On a note

  If, due to the peculiarities of the roofing structure, it is not possible to equip it or at least provide the required gap, then to combat attic dampness, windows are installed in the end parts.

  How to attach a ridge to a roof: from corrugated sheets, on slate

  The method of fastening depends entirely on the material of the protective strip. Figured elements are often made from the same material.

  

  A mandatory procedure is waterproofing wooden roof elements. Before installing the finishing elements, the purlin is covered with roofing felt tape.

  • . Let's look in more detail at how to install a ridge on a roof made of corrugated sheets.
  • The roof structure assumes that there is a gap of approximately 5 cm between the covering and the top in the ridge area, which provides ventilation. In the same area parallel to the axis on both sides of the roof, sheathing bars are additionally mounted.