At what angle to make the roof. Calculation of the angle of the roof

Building any roof is not as easy as it seems. And if you want it to be reliable, durable and not afraid of various loads, then beforehand, even at the design stage, you need to make a lot of calculations. And they will include not only the amount of materials used for installation, but also the determination of the angles of inclination, the area of ​​\u200b\u200bthe slopes, etc. How to calculate the angle of the roof correctly? It is from this value that the rest of the parameters of this design will largely depend.

The design and construction of any roof is always a very important and responsible business. Especially if we are talking about the roof of a residential building or a roof with a complex shape. But even the usual shed, installed on a nondescript shed or garage, just needs preliminary calculations.

If you do not determine the angle of inclination of the roof in advance, do not find out what optimal height the ridge should have, then there is a great risk of building such a roof that will collapse after the first snowfall, or that’s it. finishing coating it will be torn off even by a moderate wind.

Also, the angle of inclination of the roof will significantly affect the height of the ridge, the area and dimensions of the slopes. Depending on this, it will be possible to more accurately calculate the amount of materials required to create the rafter system and finish.

Units

Remembering the geometry that everyone learned in school, it is safe to say that the angle of the roof is measured in degrees. However, in books on construction, as well as in various drawings, you can also find another option - the angle is indicated as a percentage (here we mean the aspect ratio).

Generally, slope angle is the angle formed by two intersecting planes- overlapping and directly the slope of the roof. It can only be sharp, that is, lie in the range of 0-90 degrees.

On a note! Very steep slopes, the angle of which is more than 50 degrees, are extremely rare in pure form. They are usually used only for decorative design roofs, may be present in the attic.

As for measuring the angles of the roof in degrees, then everything is simple - everyone who studied geometry at school has this knowledge. It is enough to sketch a roof diagram on paper and use a protractor to determine the angle.

As for the percentages, then you need to know the height of the ridge and the width of the building. The first indicator is divided by the second, and the resulting value is multiplied by 100%. Thus, the percentage can be calculated.

On a note! At a percentage of 1, a typical degree of inclination is 2.22%. That is, a slope with an angle of 45 ordinary degrees is equal to 100%. And 1 percent is 27 minutes of arc.

Table of values ​​- degrees, minutes, percent

What factors affect the angle of inclination?

The angle of inclination of any roof is influenced by a very large number of factors, ranging from the wishes of the future owner of the house to the region where the house will be located. When calculating, it is important to take into account all the subtleties, even those that at first glance seem insignificant. Into one beautiful moment they can play their part. Determine the appropriate angle of inclination of the roof should be, knowing:

• types of materials from which the roof pie will be built, starting from the truss system and ending with the exterior finish;
• climate conditions in the area (wind load, prevailing wind direction, precipitation, etc.);
• the shape of the future building, its height, design;
• purpose of the building, options for using the attic space.

In those regions where there is a strong wind load, it is recommended to build a roof with one slope and a small angle of inclination. Then at strong wind the roof is more likely to stand and not be torn off. If the region is characterized a large number of precipitation (snow or rain), then it is better to make the slope steeper - this will allow precipitation to roll / drain from the roof and not create additional load. Optimal slope pitched roof in windy regions it varies between 9-20 degrees, and where there is a lot of precipitation - up to 60 degrees. An angle of 45 degrees will allow you to ignore the snow load in general, but in this case the wind pressure on the roof will be 5 times greater than on a roof with a slope of only 11 degrees.

On a note! The greater the roof slope, the large quantity materials will be required to create it. The cost increases by at least 20%.

Pitch angles and roofing materials

Not only climatic conditions will have a significant impact on the shape and angle of the slopes. An important role is played by the materials used for construction, in particular - roofing.

Table. Optimum slope angles for roofs of various materials.

On a note! The lower the roof slope, the smaller the pitch used to create the crate.

The height of the skate also depends on the angle of the slope.

When calculating any roof, the reference point is always taken right triangle, where the legs are the height of the slope at the top, that is, at the ridge or the transition of the lower part of the entire rafter system to the top (in the case of attic roofs), as well as the projection of the length of a particular slope onto the horizontal, which is represented by ceilings. There is only one constant value here - this is the length of the roof between the two walls, that is, the length of the span. The height of the ridge part will vary depending on the angle of inclination.

Knowing the formulas from trigonometry will help to design the roof: tgA \u003d H / L, sinA \u003d H / S, H \u003d LхtgA, S \u003d H / sinA, where A is the angle of the slope, H is the height of the roof to the ridge area, L is ½ of the entire length roof span (with a gable roof) or the entire length (in the case of a shed roof), S - the length of the slope itself. For example, if it is known exact value the height of the ridge part, then the angle of inclination is determined by the first formula. You can find the angle using the table of tangents. If the calculation is based on the angle of the roof, then you can find the ridge height parameter using the third formula. The length of the rafters, having the value of the angle of inclination and the parameters of the legs, can be calculated using the fourth formula.

What affects the angle of the roof

Roof construction is final stage building a house. But no less important than building walls. After all, the roof protects our housing from bad weather, and the aesthetic side of our home depends a lot on the type of roof.

It just so happened, but flat roofs in our country can only be found near high-rise buildings. Cottages and private houses are crowned with pitched roofs. And one of the main design indicators in the construction of a house, builders consider the angle of inclination of the roof. Let's look at how to correctly calculate this indicator, what it depends on and how it affects the construction of the roof as a whole.

Types of roofs and their dependence on the angle of inclination

Depending on the device of the roof, there are several types of roofs:

1. Single roof. The roof is inclined plane, which lies on the walls of different heights. For such a roof, any material is suitable.
2. Gable roof. This is a fairly reliable and easy to install roof. Consists of two slopes. You can also choose absolutely any material for the roof.
3. Shaft cover. The roof is a structure in which several isosceles triangles close at one point with their vertices. The rafter system of such a roof is quite complicated, but Supplies it needs a minimum.
4. Hip roof. It has four slopes (two triangular and two trapezoidal). The tops of the roof have been cut off. By their design, the roofs are very complex, but very economical in terms of material consumption.
5. Vaulted cover. Such roofs are made only of brick or stone. And since they are very heavy, today in individual construction almost never used
6. Multi-gable roofs. A very complex but beautiful configuration of many junctions and edges.

So, the roof is considered pitched if the angle of inclination of the roof exceeds 10 degrees.

Allocate exploited and non-exploited roofing.

An unused roof is when there is almost no space between the roof itself and the upper ceiling, or this space is intended for technical purposes. Such roofs can be flat roofs with a slope angle of 2 to 7 degrees. In such roofs, the height of the space between the roof and the ceiling is not more than one and a half meters.

Building flat roofs is profitable. Minimum cost for materials and labor. The wind won't blow. Again, you can equip an additional place to relax. IN Lately it is very popular to lay green roofs on such roofs. But precipitation can ruin such a roof. Therefore, it is unprofitable to make completely flat roofs. Precipitation in puddles will accumulate on the surface of the roof and destroy it.

In order to create a natural outflow of water, a layer of ceramite is poured onto flat roofs under a certain slope.

Pitched roofs allow you to use the space under the roof for household needs - an attic, an attic, or even equip living rooms in them with careful insulation.

Factors on which the angle of inclination of the roof most depends

The main factors affecting the slope of the roof include:

• natural factors. The slope of the roof depends on the climate of the area where the construction will take place. The wind exerts a huge load on the roofing of the roof and on the truss system as a whole. Slightly increasing the slope angle (approximately 30 degrees) increases wind load almost 5 times. But even a slight angle can also play into the hands of the elements. So it will be easier for him to get into the roof through the joints of the coating and easily tear off the roof. Precipitation can also be destructive to performance characteristics roofs. But with the help of a well-chosen bias, you can avoid these troubles.

Remember that the maximum snow load on the roof of the roof is achieved by observing the angle of the roof slope of 30 degrees. And at 45 degrees, snow and rain do not linger on the roof at all.

Thus, it is obvious that if you are going to build a house in a region where rainfall is very frequent, then a roof slope of 45 degrees is just right. But if there is not so much precipitation, but the wind blows all year round, then best option– Roof with a slope of 30 degrees.

How to calculate slope angle

How to determine the roof slope that will be optimal for your new home?

Remember what more angle slope of the roof, the more costs you will incur for construction work.

The slope is calculated as the ratio of the size of the ridge to half the width of the building and multiplied by 100. professional builders in the case of calculating the roof slope indicators, there are instructions and calculations. Most of them use calculation matrices and special charts. You can find them on the World Wide Web.

The influence of the slope of the roof on the choice of roofing material (and not only)

An ideal roof that would suit all regions and roofing materials has not yet been invented.

So, the slope was calculated. Now we select the roofing material. Slate and shingles are suitable for roofs with an angle of more than 20 degrees. If the slope is smaller, then water will run into the joints, snow will clog, which means that the life of the roof itself will decrease.

Roll materials based on bitumen are used when covering flat roofs or the angle of inclination of the roof, which exceeds 30 degrees. At high level heating such roofs by the sun and with a greater slope, the roof can simply slide off.

Metal profiles and metal tiles are used on roofs with a slope of at least 10 degrees.

And here is a list of the most common roofing materials:

1. Tiling. Today it is almost wildly popular. There are many varieties of this material. These roofs are easy to repair. But to give finance for given material will have a lot But this material is very durable. Its service life can be calculated not only in decades, but also in centuries.
2. Roof panels. Such panels are made directly at factories and in the final form they represent almost finished roof. The panels immediately contain several layers - both thermal insulation and vapor barrier and the plate itself. Installing these boards is very easy. No special equipment needed. The panels are attached to each other with a special tape. But such material is very expensive.
3. Metal profile. Galvanized steel sheets. Relatively light and durable material. Rust resistant and environmentally friendly. Today you can choose any color and size and direction of the waves. Manufacturers give a guarantee for this material for a period of 75 years.
4. Piece materials from wood, such as shingles, shavings and shingles. Typically, such materials modern construction no one is using it anymore. This material is not durable, can rot, micro-organisms multiply and is easily flammable.
5. Slate. This material is now for a long time remains reliable in operation, easy to install and inexpensive to purchase. Moisture-resistant, frost-resistant, fireproof. Yes, and the appearance today, manufacturers have improved. You can choose a slate of any desired color.

When choosing a roofing material, remember that the denser its structure, the smaller the roof slope should be.

When using sheets of metal profiles and metal tiles on sloping roofs, it is recommended to pass the joints with a moisture-resistant and frost-resistant sealant. As well as the size of the overlap of the sheets during the installation of the roof of these materials also depends on the angle of the roof. The steeper the roof, the less overlap. This also applies to slate.

When installing the roof, do not forget about the ventilation of the space under it. pitched roofs must also be equipped with a drainage system.

Thus, we can conclude that the angle of the roof is a very important indicator. Not only the quality of work depends on it, but also the life of the roof itself. The main thing is to correctly calculate the value, choose the desired roof structure, high-quality roofing material and a good team of workers. And, of course, not all of this will require some voluminous budget. Good luck with your building!

The crown of building a house is always the roof, and what it will be depends not only on the wishes of the homeowner, but also on how how to calculate roof pitch.

Installation rafter legs usually does not cause difficulties if there are necessary fasteners, however, when checking the angle at which the slopes will be laid, you can make a mistake if you do not know some of the subtleties. For example, a very high roof in an area with strong winds will be constantly subjected to heavy loads and, as a result, will most likely be destroyed. Therefore, in order to avoid this, sometimes it is worth giving preference to a not too spectacular, but stable low roof. There are many such examples, but consider the factors themselves that affect the height of the roof. What might she depend on?

As it has already become clear, before calculating the angle of the roof, it is first necessary to take into account the climatic features of the region. So, for example, the sharper the gable roof, the worse snow is retained on it and flows off it more easily. rainwater. However, what is fraught with such a steep slope, with a strong wind, we already know. In places where the sun is hot, it is better to build slopes with minimal slope or do without them altogether, that is, make a flat surface of the roof, which receives and transfers heat the more down, the larger its area. The latter increases in proportion to the steepness of the slope.

The more sloping the roof, the higher the likelihood that strong gusts of wind and rain will drive moisture under the edges roofing.

Among other things, you should consider how the space under truss system- as an attic or as a residential attic. In the first case, the distance to the ridge is less than the average height of a person. In the second case, it is necessary that there be enough comfortable space for movement, that is, the clearance in the center of the room should be at least 2.5 meters and, preferably, at least one and a half meters at the lowest point of the ceiling. The roof slope can be significantly affected by the roofing material, which can only be laid at a certain degree of slope.

The most important thing in any room is its effective area, that is, one that can be used for arranging furniture and moving, as well as for storing things. In sometimes it is difficult to use some areas of space where the lowest point of the ceiling sheathing is located. However, such places can just be taken away for storing things by making built-in lockers and cabinets there. Another thing is the zone of free movement, its area directly depends on the height of the ridge, and hence the angle of the roof.

Let's look at an example. Let's say the width of the house is 9.5 meters. If you want space above your head within 3 meters, at least in the center of the room, then the angle between the slopes should be at least 35 degrees, since already at 30 the height of the ridge will be slightly more than 2.5 meters. However, it should be borne in mind that then the width of the space available for free movement (up to a two-meter ceiling level) will turn out to be a little more than 3.5 meters. If you keep the same height at the lowest points of the sloping ceiling, and at the same time make the roof angle 30 degrees, then the width of the room will be reduced to 2.4 meters. It will be most comfortable in the attic under a roof with an angle of more than 40 degrees, however, it should be borne in mind that in such a design, in comparison with a gentle slope (about 10 degrees), the wind load increases by almost 5 times.

In general, the dependence of the angle of inclination of the roof on the height of the ridge only facilitates the calculations of the truss system.

Roof Angle Calculator

However, for calculations, you need to know the basics of geometry quite well. Most often, the section of the roof structure from the side of the gables is a triangle, equilateral, isosceles or another type. Accordingly, using the simplest formulas, you can calculate the length of any side and the angle adjacent to it, knowing the base and height. At the same time, in addition to the measuring tape, we will need the Bradis table, since we will have to deal with tangents.

Typesetting materials also do not tolerate steep slopes, for the simple reason that they can move out under their own weight at the slightest prerequisite for this, such as a storm gust. However, the angle cannot be made too small either, since in this case the mass roofing material will unnecessarily load the supporting structures, that is, the rafters, the crate and other elements. An angle of 22 degrees is considered optimal, sufficient for moisture to drain freely during rain and not be blown by the wind under the joints.

With regard to corrugated board and metal tiles, the minimum slope is 12 and 14 degrees, respectively, gently sloping so that precipitation flows off the roof, and at the same time its tightness at the joints is not violated. In a larger direction, the steepness can increase without restrictions, however, taking into account the fact that a large roof area has a solid mass. Also, one should not forget about the wind load and the high windage of roofs with an angle close to 45 degrees. Optimal slope- about 27-30 degrees.

But at soft tiles, which consists of separate pieces of material standard size, the angle of the roof is related to the density of the crate. If the slopes are very gentle, then the distance between the planks should be made as small as possible. This is due to the fact that snow masses can become an unbearable load for the coating. In the case when the steepness of the slopes is maintained within 30-40 degrees, the step of the crate is allowed to be larger, up to 45 centimeters.

The comfort of operation and the reliability of the building mainly depend on how well and competently the construction of the roof is carried out, and also on how correct the slope of the roof is. about him and will be discussed Further.

The slope of the roof of the house mainly depends on the design of the facade and the roof of the building, and the material chosen for the coating is also an important feature. The slope is taken into account depending on climatic conditions the region in which the new building is being built. For example, in areas where there is heavy rainfall, and in winter period very heavy snowfalls, choose a ramp slope from 45 to 60 degrees. Such an angle of inclination is specially designed, as it allows you to reduce the load, especially in winter, on the roofing system, since snow simply will not accumulate on the roof, but will slide down due to its own weight.

And if they are constructing a roof for a region where strong and constant winds are typical, then they choose the minimum one, since this reduces the so-called "sail" of the roofing. Basically, the angle is chosen from 9 to 20 degrees. Therefore, the most universal solution is a value chosen between the two ranges above, i.e. it is best to make an angle of 20-45 degrees. A slope of 20 to 45 degrees has another advantage - the ability to use most roofing materials purchased in today's markets.

Varieties of roofs of houses

Varieties of roofs: a - gently sloping gable, b - steep gable, c - hip four-slope, d - single-slope (in the form of a desk), e - broken (mansard) gable, e - hipped four-slope, f, h, i - half-hip (mansard) four-slope.

The most common for utility or utility buildings is the shed roof shape of the house, which does not offer an original design, but at the same time attracts with its simplicity of construction and its low cost. The design of such a roof consists of walls and roofing material laid on them.

The slope in this case should be from 9 to 25 degrees, since most often it is these roofs that are later covered with corrugated board. Such a rather small angle of inclination is formed due to the lack of an attic area.

Another fairly common type is the gable roof of the house. Its design consists of two slopes (two planes), connected by a ridge (one line). The walls are the ends of the building and they are called gables. They often provide doors that will allow you to use the attic as an additional room, in addition, these doors play the role of ventilation (ventilation openings). Making such roofs is easier than everyone else.

Modern designers and just builders often make hip roofs. They allow you to perform unique design façade and roof of a broken shape. In such structures, the slope angle can be absolutely anything, depending on the imagination and taste of the person who designs the roof structure. There are practically no restrictions on the use of roofing material in the construction of such roofs. Complex design compensated by spectacular appearance roofs of the house, and the more complex the general plan, the more original design hip roof it might work out.

A more complex type of hip roof is mansard roof broken shape, the purpose of the construction of which is the use of attic space in a residential area, while it is necessary to make insulation and vapor barrier.

Due to rather high angles of inclination and slopes of a broken shape, a space is formed, of which the entire attic floor. In addition, it would be appropriate to make the so-called "dormer" windows, which will serve as an additional decoration of the facade. And you just need to perform insolation (lighting the room with sunlight).

You should also familiarize yourself with the data on the smallest angle for various materials:

1. For piece materials, such as tiles and slate, the smallest angle is considered to be 22 degrees. This prevents moisture from accumulating at the joints and seeping into the building.
2. For roll materials the minimum angle of inclination will be selected depending on the number of layers laid. With a three-layer coating, the angle will be from 2 to 5 degrees, with a two-layer coating - 15 degrees.
3. A small angle of inclination of a corrugated roof is 12 degrees. At small angles, according to the recommendations of the manufacturers, the joints should be additionally glued with sealants.
4. For roofs covered with metal tiles, the minimum angle is 14 degrees.
5. For roofs covered with onduline, the minimum angle is 6 degrees.
6. For soft tiles, a small angle is 11 degrees, while regardless of the selected angle, there is required condition- installation of a continuous crate.
7. Membrane covers have a minimum angle of 2 degrees.

Roof Slope Calculation Example

The angle of inclination of the roof is calculated, as we have already said, taking into account the climate of the area and the selected coating material. The height of the ridge and the value of the rise of the rafters are determined with a square or the width of the span is calculated, divided in half and multiplied by the corresponding coefficient from the table.

For example, if the width of the house is 10 m, and equal to 25 degrees, then the height to which the rafters must rise is calculated by multiplying 5 m (half the width of the house) by the coefficient from the table (0.47) and we get 2.35. It is to a height of 2.35 that the rafters should rise.

The metal tile is considered one of the most convenient and popular roofing materials. Featuring a high bearing capacity, strength, ease of installation, metal tiles are little subject to mechanical stress. When planning the layout of the material, it is necessary to calculate the correct slope for the metal tile and observe the technological details of installation. Then the roof will serve for a long time and will not require an early renewal.

The slope of the roof is an important defining structure, formed by an angle cut off by the floor plane and roof slope. The indicator is expressed as a percentage or degrees, calculated by dividing the height of the ridge by 1/2 of the width of the building. The angle of inclination of a roof made of metal tiles is regulated by SNiP and the supplier's instructions. The indicator depends on factors such as:

1. Roof covering application.
2. The ability of the roof to effectively remove natural precipitation, withstand winds and other climatic phenomena.
3. Roofing price.
4. The mass of the roofing cake.

A fairly new coating, metal tile, is not so strictly regulated by standards. Therefore, the manufacturer himself often advises the indicator minimum angle, relying on specifications products. The calculation is made according to the thickness of the sheet, bearing capacity basics and method of laying roofing. However, there are optimal values on which to rely:

• With a slope of 6 meters in length, the minimum slope according to SNiP must be at least 14 °.
• The permissible slope of the roof of metal tiles should be in the range of 14-45 °.
• The optimal value of the angle is 22°, this indicator is sufficient for the normal removal of precipitation with a slope area of ​​​​less than 6 meters.

The choice of the roof slope is not always simple, therefore, based on the indicators of SNiP, one should take into account the following recommendations for the equipped slope slope:

1. The level of snow load in the construction region. To determine the indicator, you need to take information from the directory and calculate the average annual amount in the winter. The thicker the snow cover, the greater the level of slope, otherwise the snow mass will linger on the roof, which will lead to deformation of the sheets.
2. Wind load - the indicator also depends on the characteristics of the region. At the maximum intensity of wind flows, the angle of inclination is small, which reduces the windage of the slopes.

Advice! The number of hurricanes, tornadoes and other natural disasters. The information is taken from reference books.

Features of metal roofs with a small slope

The lowest slope angle is 14 °, but experienced roofers lay materials when calculating an angle of 10-14 °. And to ensure the reliability of the roofing carpet and reduce the risk of leaks, the following actions are performed:

• The frequency of the laths in the crate increases by reducing the inter-rafter step.
• The rafter system is strengthened by means of a frequent or continuous crate.
• Significantly increase the number of overlaps! Despite the recommendations of manufacturers for a horizontal overlap of 8 cm, a vertical overlap of 10-15 cm, the overlap increases by the width of the wave. Thanks to this method, the strength of the roofing carpet increases and the risk of leaks on the roof of a small slope is eliminated.
• Carefully seal the joints with a silicone-based sealant.

Advice! All measures taken are temporary, so a visual inspection of the roof once a year will not hurt.

Determination of the roof slope by geometric dimensions or in degrees

The formula for calculating the steepness of the slope for a roof made of metal by size, for example, for gable roof calculated using the following formula: I = H/(1/2L), where:

• I - the desired angle for the metal tile;
• H - the distance from the border of the ceiling to the ridge, that is, an indicator of the height of the rafter structure;
• L - dimensions of the width of the building.

To find the percentage, the resulting index i is multiplied by 100. And for the expression in degrees, you should use trigonometric function or find the value in the corresponding table:

Important! This type calculation is suitable for single, gable roofs. For a single-slope, the entire span length is taken into account. In the case of arranging a roofing carpet with an asymmetrical slope, the roof angle is calculated from the distance from the projection point of the ridge element to the ceiling for each slope separately.

The optimal angle for a roof with complex structural elements a correction factor for projection in the horizontal direction is taken into account:

• Roof angle 1: 12 (7°) - K = 1.014;
• 1:10 (8°) = 1.020;
• 1:8 (10°) = 1.031;
• 1:6 (13°) = 1.054;
• 1:5 (15°) = 1.077;
• 1:4 (18°) = 1.118;
• 1:3 (22°) = 1.202;
• 1:2 (30°) = 1.410.

Criteria for choosing the angle of inclination

When calculating the angle of inclination of a roof for a metal tile, you need to know that a small steepness has its advantages:

1. economical consumption of materials;
2. reduction in the weight mass of the roofing carpet, the sheet windage index, which minimizes the risk of defects during heavy winds;
3. convenience and simplicity of arranging drainage systems.

But there are also disadvantages, if the slope of the roof is minimal, then:

1. it is necessary to seal the joints as much as possible, since the almost complete absence of a drain increases the possibility of moisture penetration through the attachment points;
2. it will be necessary to remove snow blockages on the roof more often so that the metal tile is not subjected to increased load;
3. the need to equip a powerful crate will require a calculation of the bearing capacity of the base and complicate the fastening of roofing elements;
4. under flat roof it is not always possible to equip spacious residential / non-residential premises.

But if the slope of the roof is large, for example, 45 °, then, despite the free melting of the snow cover, the mass of the coating is increased, due to which the sheets simply slide off. The way out is to strengthen the fasteners and strict adherence to the installation technology of the roofing carpet. In addition, when the angle of inclination of the metal roof is too steep, the consumption of roofing material increases, as with the arrangement of curly slopes.

In order not to calculate which angle will be better, take the recommendations of experienced roofers as a basis: for shed roofs is 20-30 °, for gable - 25-45 °. AND a little advice: when arranging the lathing with frequent steps, a kind of shock-absorbing cushion is obtained that strengthens the roofing carpet. Knowing the calculation formula, it is easy to calculate different variants the steepness of the slopes and decide which angle to give preference to, depending on the weather, climatic conditions and the financial component: whatever one may say, on roofs with a minimum slope, material consumption is less.