What is the minimum roof pitch? Roof slope: why is this parameter so important and how to calculate it correctly. Roof slope degree-percentage ratio

One of the most important tasks in designing a roof made of profiled metal is calculating the angle of inclination. You’ll have to put aesthetics aside and think through all the details: the roof-to-roof ratio parameter total area affects the presence or absence of free attic space, problems with snow melting and resistance to wind loads. That's why it's important to know minimum slope roofs made of corrugated sheets, possible maximum values ​​and objective reasons for choosing one or another value of the slope slope being arranged.

According to construction regulations, the permissible minimum slope of a corrugated roof is 8°. With this level of slopes, the roof remains resistant to wind loads and minimizes the risk of precipitation penetration. The sheathing pitch in this case is 0.4 m.

However, an indicator of 8° is allowed for utility buildings, industrial use, for residential buildings the permissible slope is at least 10°. When laying out the roofing carpet in two or more layers, the slope of the corrugated sheet roof should be even greater. That is why construction companies rarely agree to work with roofs whose slopes are less than 12° steep. Maximum indicator The angle for the profiled sheet reaches 70°. Thus, when thinking about the slopes of the structure being built, you should take into account other parameters that affect the level indicator.

Important! Optimal choice The slope angle is considered to be 20°. In this case there is no need high costs material, it is possible to lay out in 2 layers, good melting of snow deposits is ensured and the risk of moisture seeping through the fastener holes is minimal.

Accepted construction terms:

1. The flat roof has an inclination angle of up to 5°;
2. Pitched - from 20° (considered the most practical and convenient for the construction of private buildings);
3. A roof with a low slope of up to 25° is suitable for arranging attic spaces without large windows;
4. Steep slopes up to 40° are made if it is necessary to arrange a spacious residential attic with large windows;
5. The large roof has an angle of 45-60°.

Small slope of slopes: advantages and disadvantages

The main advantages of a flat roof:

• Minimum consumption of materials;
• Comfortable, lightweight and safe work for installation of roofing sheets;
• Absence ridge element, which means worries about sealing it, cutting and laying out metal elements.

In addition, flat roofs are a lighter load on the rafter system. The steeper the slope, the more massive the roof, therefore: a reinforced base, accurate calculation of endurance, etc.

Disadvantages with minimum angle:

1. Insufficient movement of precipitation. Snow and rain flows off a flat roof less quickly, so careful sealing of all joints and cracks will be required. The limiting indicator at which you do not have to spend a lot of time sealing joints is considered to be an angle of 12°; a smaller angle requires sealing with special hermetic agents at all joint points of the roofing material.
2. The selected angle of inclination of a corrugated roof recommends the type of material. Yes, for flat pitched roofs shown roofing sheet with a high wave - it better withstands loads. For more steep slopes Can be used universal wall type material - reduced pressure on the corrugation and ensuring the natural descent of sedimentary phenomena minimizes the risk of sheet deformation.

Important! When building a roof with a slope angle of 12-14 ° the overlap increases when laying out the sheets, but for now the usual sealing of the substrate is sufficient. Reducing the angle of inclination for corrugated sheeting will require both an increase in material consumption due to frequent overlap, and the use more sealant. Therefore, the roof slope level should be from 15 to 30°.

Despite the fact that when arranging steep roofs you will have to spend time and money on arranging an elongated rafter system, good savings are gained on the material. In addition, a spacious under-roof space is obtained; by making it insulated, the developer reduces heat loss by at least 10-12%. And finally, the small angle of the roof slope is a complex reinforced rafter system that will bear a massive load. A minimum roof slope will require more additional supporting elements.

Additional considerations when choosing a slope angle

Even having decided to make a small angle of the roof slope, the developer does not always get what he wants. The choice of indicator is influenced by the climatic conditions of the region: wind, snow loads, frequency and abundance of precipitation.

Thus, the minimum slope of a corrugated roof is indicated in regions with high wind intensity. This option reduces the “windage” of the roofing material. SNiP requirements recommend the following values:

1. With average wind loads, the roof steepness limit should be 35-45°;
2. Strong winds – 15-25°;
3. Hurricane winds – up to 8°.

However, to equip completely flat roof it’s not worth it, hurricane phenomena “cope” perfectly with both overly steep roofs and flat ones. An average of 8-14° will be optimal.

The second factor is snow load; there are regions where precipitation levels reach 75 kg/m or more. It is not easy for a flat roof to withstand such a mass; the rafter system will not be able to withstand the load and will simply break, or the owner will have to clean the snow cover every day. The optimal roof angle for natural snow melting is 25-45°. In this case, significant strengthening of the rafters will not be required; the piles of snow themselves will roll down perfectly.

How to calculate the angle of inclination yourself and without formulas? It’s all quite simple: look at your neighbors’ roofs, how steep their slopes are and follow their example. As a rule, development is carried out at the most optimal level, and it is impossible to make a mistake here. Otherwise you will have to use special trigonometric formulas and tables of values.

Advice! To avoid studying complex calculations, you should determine the height of the ridge to the ceiling to half the width of the ceiling. Now divide the height indicator by half the width of the building, divide the resulting result by 100 - the required figure is ready.

Shed roof

When erecting a shed-type structure, it should be remembered that the slope of a shed roof made of corrugated sheets is also calculated based on the level of precipitation and wind loads. If there is heavy snow cover in the region, a temperature of 45° is allowed. With average precipitation pitched roof maybe 25° steepness. But it all depends on the wind: the stronger it is, the minimum the steepness of the slope should be

Important! Minimum indicator for tilt pitched roof according to SNiP for residential buildings is 12 °, the optimal figure is considered to be 20°.

The reliability of any building, as well as the comfort of living in it, depend mainly on how well its roof is constructed.

And one of the criteria for the quality of a roof is its slope.

Since the amount of roofing material depends on its size, the choice of the angle of inclination and its preliminary calculations are carried out before the purchase of the selected roofing material begins.

What affects it

Depending on the slope of the roof slopes, the features of its operation depend.

It is customary to distinguish 4 types of roofs:

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

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

Strong winds place the greatest pressure on high roofs.

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

U large area the surface has a very high windage.

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

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

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

With this type of roof bottom part the stingray will turn out to be high blood pressure in strong winds.

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

Therefore, in areas where strong winds often occur, it is recommended to arrange pitched roofs with an inclination of 25 - 30 degrees.

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

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

In this case, the high roof is beyond competition.

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

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

The smaller the roof slope, the longer the fallen snow will remain on the slopes.

The more weight will affect the entire structure.

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

It provides a little extra insulation.

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

We choose the slope depending on the roofing material used

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

Today there are a huge number of roofing materials!

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

After all, it may happen that the material you like is simply not suitable according to its parameters.

Minimum tilt angle

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

This parameter is different for each material.

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

A lot of problems can arise in the future if you break this rule:

• for any piece of inlaid roofing materials, such as tiles or slate, the minimum slope is 22 degrees. It is with this value that moisture does not accumulate at the joints and moisture does not leak into the roof;
• tilt angle for roll materials(roofing felt, bicrost, etc.) depends on the number of layers you plan to lay. If there are three layers, then the slope can be 2-5 degrees. If there are two layers, then it needs to be increased to 15 degrees;
• Manufacturers of corrugated sheets recommend setting a slope angle of 12 degrees when installing a roof from this material. Corrugated sheeting can be used at lower values, but in this case it is necessary to glue the joints of the sheets with a sealant;
• For metal tiles the value of this parameter is 14;
• for ondulin it is a value of 6 degrees;
• minimum slope for soft tiles equals 11 degrees. But at the same time, a prerequisite is a continuous sheathing;
• There are no strict requirements for membrane roofing coverings. minimum value this parameter.

This is about minimum values.

I'll give you some advice - stick to these rules.

So that in the middle of winter you don’t have to re-cover the entire roof.

Now about the optimal values

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

Because the strength of the rafter system is not unlimited.

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

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

With a smaller inclination, its windage decreases.

And there are no excessive loads on the roofing material and rafters.

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

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

Very often there is snow and wind in the region.

For example, Orenburg region.

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

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

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

We calculate its value

For a single slope

Since a pitched roof rests on walls of different heights, the formation of a given angle of inclination is carried out by simply raising one of the walls.

We draw a perpendicular L d along the wall, originating at the point where the short wall ends and resting on the wall that has the maximum length.

The result is a right triangle.

If the length of the wall L сд is equal to 10 meters, then to obtain a slope angle of 45 degrees, the length of the wall L bc should be equal to 14.08 meters.

For gable

The calculation principle for a gable roof is similar to the previous principle.

Let's look at an example

Leg C is half the width of the building.

Leg a is the height from the ceiling to the ridge.

The hypotenuse is the length of the slope.

If we know any two parameters, then the angle of inclination can be easily calculated using a calculator.

If the width is 8 and the height is 10 meters, then you should use the formula:

cos A = c+b

Width c = 8/2 = 4 meters.

As a result, the formula looks like this:

cos A = 4/10 = 0.4

Using the Bradis tables, we find the value of the angle to which a given cosine value corresponds.

It is equal to 66 degrees.

For hipped

And again you can’t do without roulette and Bradis tables.

Knowing several parameters, you can easily calculate others.

Including the angle of inclination of the hipped roof.

It should be remembered that all dimensions must be taken as accurately as possible.

And it will help to measure the slope of an already built roof special tool— inclinometer.

After all, if you make a mistake, then the angles of inclination, length and area may not be correct.

This means that you will make a mistake in the amount of material required or the strength of the roof will be lower than planned.

Watch a video about the slope of the ramps.

Sergey Novozhilov - roofing materials expert with 9 years of experience practical work in area engineering solutions in construction.

Metal roofs are a practical and popular solution for the construction of private low-rise buildings. This roofing material is characterized by high bearing capacity, resistance to mechanical damage external factors environments and intense loads. Durability and reliability finishing coating depend not only on quality, these characteristics are influenced by the roof design, including the correctly selected minimum slope. In this article we will tell you how to choose the right slope angle and check it for compliance with SNiP.

Roof slope – important parameter structure, which indicates the angle formed by the plane of the floors and the roof slope. This indicator is expressed as a percentage or degrees. It is calculated as the result of dividing the height of the ridge by half the width of the building. The angle of inclination of the slope depends on the technical and operational properties

1. material and is regulated by SNiP and manufacturer’s instructions. It depends on: Possibility of using one type or another.
2. roofing
3. Design, composition and cross-section of rafter frame elements.
4. The ability of a roof to effectively drain precipitation.
5. Cost of roofing work.

Weight of the roofing pie.

Note! If the slope of a metal tile roof is increased from 22 degrees to 45 degrees, the area of ​​the slope will increase by 20%, which will affect the cost of materials (finish coating, waterproofing, insulation, wood), as well as the weight of the structure. It is necessary to decide on the optimal angle of inclination during the preparation of the project in order to correctly determine the load on the foundation.

Optimal values Metal roofs are relatively new constructive solution

• , therefore, the technology of its installation and operation is not clearly regulated by SNiP. Information on what the minimum roof slope should be is provided by the manufacturer, since this indicator directly depends on the technical characteristics of the material itself.
• This indicator is calculated in accordance with the thickness, load-bearing capacity and method of laying the roofing.
• According to SNiP, the minimum angle of inclination of a metal tile roof, if the length of the slope is 6 meters, must be at least 14 degrees.

The permissible slope for a metal roof is in the range of 14-45 degrees. The optimal angle of inclination, which ensures effective removal of precipitation with less impact on the slopes, should be 22 degrees. Important! The minimum slope of a metal tile roof allowed by manufacturers is 11 degrees. Some brands of material can be laid even if the slope is 10 degrees steep. A reduction in this indicator was achieved by the use of new, smoother polymers and more

durable steel

It can be difficult for a non-professional builder to correctly select the minimum angle of inclination of a metal tile roof. This indicator, in addition to SNiP requirements and manufacturer’s recommendations, is influenced by other factors that also need to be taken into account.

When choosing the steepness of the slope, the following are taken into account:

Please note that the choice of slope slope depends on the roof design. The optimal angle of inclination of the slopes of a pitched roof made of metal tiles is 20-30 degrees, and that of a gable roof is 20-45 degrees.

Features of roofs with a small slope The minimum recommended pitch for a metal roof is 14 degrees, however experienced craftsmen

1. can efficiently lay this type of roofing material, even if the slope of the slopes is within 10-14 degrees. To increase the reliability of such a design and reduce the risk of leaks, the following measures must be taken: Increase the frequency of the sheathing slats and reduce the pitch between the rafters. To minimize the risk of roof collapse due to intense snow load, it is necessary to strengthen rafter frame structures and install frequent or.
2. continuous sheathing
3. Increase overlaps. Manufacturers recommend when installing metal tiles to make a horizontal overlap of 8 cm, and a vertical overlap of 10-15. To eliminate the possibility of leakage in structures with gentle slopes, you can increase the overlap at the joints of the sheets. Insulate joints. To prevent the penetration of melt and rain water between the joints of the sheets, you can treat the seams silicone sealant

, although this measure has a limited duration.

Experienced craftsmen claim that the easiest way to make a roof made of metal profiles reliable is to follow the manufacturers’ recommendations and strictly adhere to the recommended angle of inclination.

Video instruction The reliability of the building and the comfort of living in it depend on the quality of roof construction. Its design is selected optimal for local operating conditions. Special meaning

has such a parameter as the slope of the roof, which will be discussed further. The angle of the roof slope depends not only on its design and the features of the facade of the house, on the selected roofing material, but also on other factors. It is necessary, first of all, to take into account the climatic conditions of the area where the building is being erected. Where the number of drops in precipitation is high, a large roof angle is preferable (within 45-60 degrees): this contributes to better snow melting, which means reducing the load on the roof. It also becomes less likely that the surface of the floor will freeze due to compaction of snow covers.

If the building is being erected where weather conditions prevail strong winds, it is advisable to choose the minimum roof slope angle to reduce the windage of the structure. Otherwise, the structure is in danger of rapid destruction. Most often the tilt range is in in this case– 9-20 degrees.

The greater the slope of the roof slope, the easier the snow cover comes off it.

But basically, the optimal roof slope angle is selected in average values, that is, from 20 to 45 degrees. It is suitable for almost any type of roofing material, for example, corrugated sheeting or metal tiles, which are very popular today.

In areas with a warm climate, where sunny days much more than cloudy ones will be more acceptable flat roofs: their area is smaller than that of other types of structures, which means heating from sun rays will occur to a lesser extent. But such a structure should not be absolutely horizontal: the slope of a flat roof should be at least within 3-5 degrees. The minimum slope of the flat roof will ensure normal drainage of rain and melt moisture.

Types of roofing structures

Utility and utility buildings are often built with a pitched roof: it is easy to install and does not require large expenses. In essence, such a building has different heights walls with ceilings laid on them. The slope of the ceiling is selected within the range of 9-25 degrees, which is well suited for corrugated sheets and metal tiles. This design requires ventilation of the under-roof space.

But the most popular is the gable one: two planes located at an angle are connected along the ridge line. Other (end) planes are vertical and are called pediments. They may have doors to access the balcony or external staircase.

There are many options for roofing structures

Hip ceilings, the most popular representatives of which are hipped ones, are aesthetically very attractive. In such cases, especially in more complex structures, the slopes can be any: it depends on the chosen design and personal preferences of the developers. Dignity hip roofs– in the absence of restrictions on the use of roofing material.

Option hip design– attic: attic space It is used as a residential building, so the requirements for insulation are very high. Free space under the ceiling is formed due to the high angle of inclination of all slopes, in which the presence of skylights.

Dependence of roof structure on floor material

Before choosing a roofing material, you should study its technical characteristics: this will help you optimally approach the issue and choose the most reliable one. In addition, there is a rule that determines the dependence of the slope angle on the roofing material used.

We list the main ones:

When choosing the slope value, the strength characteristics should be taken into account roofing structure: the safety margin must be enough not only to withstand its own weight and the weight of the roofing material, but also to withstand external loads (gusts of wind, snow). Also, the type of sheathing for laying most materials also depends on the slope of the slope: for small values ​​of this parameter, either a continuous sheathing or with a small pitch (350-450 mm) is installed. When erecting any roof, especially a flat one, it is necessary to install a system of slopes and drainage. If the area is particularly large, you will need additional drain.

Calculation of the angle of inclination

The design must meet the following requirements: be strong enough, provide reliable protection from precipitation, have good thermal and sound insulation. It is also important that there is access for repairs and maintenance. How to calculate the angle of the roof so that all these conditions are met? Experts recommend using simple options its devices, which include single-pitch, gable, hip (and half-hip), and attic.

Roofs can have a design of any complexity, with different slope angles

Single-pitch roofs are most convenient for verandas, outbuildings and outbuildings. The principle of creating a single-pitch roof is the same as other types: rafters and sheathing are installed, after which the roofing material is laid. The latter plays a decisive role: for corrugated sheeting an angle of 8-11 degrees is required (it is better to do 20), for metal tiles - at least 25, for slate and seam roofing - 35 degrees.

If climatic conditions allow, it is better to make a roof with a slope of 45 degrees: this will allow you to neglect calculations related to the mass of snow. This is an almost ideal pitched roof: the angle of inclination will not complicate its installation and will facilitate maintenance (snow will not accumulate on its surface). But in this case, it will be necessary to strengthen the rafters and sheathing, since the wind pressure on the structure increases 5 times. It should also be taken into account that this will require high costs for materials - approximately 1.5 times.

Roofing material must be selected depending on the roof slope

As can be seen from the graph, each slope corresponds to a certain group of roofing waterproofing materials. There are 11 of them in total, with the inclined lines corresponding to the angle of inclination of the slope. The thick line indicates how the height of the ridge relates to ½ of its depth. It can be seen that the segment h is equal to half of the horizontal segment, designated by the fraction ½. The numbers at the tops of the semicircular scales correspond to the angle of inclination (in degrees), the vertical scale also indicates in percentage. When choosing any roof configuration, you should adhere to these recommendations and purchase roofing materials suitable for your chosen option.

In order to make it clear how the roof slope angle is calculated, we will give an example of calculating the smallest slope angle of a roof with tile waterproofing. On the graph we find a semicircular curve corresponding to this covering: this will be the curve indicated by the number 2. Tracing it to the point of intersection with the vertical scale, we find that the minimum slope of such a roof is 50%.

Taking into account the fact that the slope of the slope is the ratio of the height of the ridge to ½ of its depth, we calculate the slope. That is, with a ridge height h = 4 m and a slope equal to L = 15 m, the slope will be determined as h: (L/2) = 4: (15/2) = 0.53. To display it as a percentage, multiply the result by 100 and get 53%. This value of this parameter guarantees good drainage of rainwater. The minimum slope in the valley is 1%.

Features of calculating a gable roof

Gable roof is the most successful and widespread design. There are several reasons for this: high reliability, relative simplicity, low cost design. When constructing a roof, not everyone chooses the optimal angle of inclination correctly. gable roof.

In the areas strong winds, it is necessary to calculate the gable roof so that its slope does not cause too strong wind loads. The greater the angle of inclination of the structure, the higher its windage.

You cannot reduce it to values ​​less than 25 degrees: precipitation will be less easily removed from the roof, and dampness may appear in the under-roof space. Making it larger than 60 degrees is also not recommended: a strong impulse of faith can destroy the roof. The roof does not have to have symmetrical slopes: if you orient the building with a more gentle slope to the south, the roof will dry better after rain.

Conditions for using roofing materials depending on the slope angle

Useful attic area and drainage system

Effective area attic room depends on the roof structure: the greater the slope angle, the larger the area and vice versa (this is clearly shown in Figure 2). When constructing an attic, you have to make a compromise between the area that can be easily used, the cost of building a roof and the strength of the structure.

The method of removing precipitation can also be different. There are external or internal organized and unorganized - only external. The latter involves installation drainpipes and gutters, while wall and suspension systems mounted on roofs with a slope greater than 15%. The gutters are attached with a minimum slope of 3 degrees, their sides are made with a height of about 120 mm.

The usable area of ​​the attic depends on the angle of the roof.

The distance between the pipes should be no more than 23 m. The cross-section of the pipe should ensure normal drainage of water and is selected depending on the area of ​​the slope. External drains of an organized type are more suitable for areas with a warm climate. Internal drains used for cold climatic conditions. Such systems consist of a funnel for receiving water, a riser, an outlet and a discharge pipe. The main condition is that water drainage must be ensured at any air temperature.

Installing a roof is a very important task that requires the participation of highly qualified workers. Installation errors can cost home owners dearly. To avoid troubles, roofing work should be entrusted to specialists with sufficient experience: this will guarantee the reliability of the building and the comfort in it.

Every potential homeowner should know how to calculate the roof pitch country house or cottages, because not only the cost of the roofing material and construction work, but also the safety of living. The correct geometry of the roof allows you to save on building materials and create a structure that prevents the accumulation of snow caps and ice blocks on the roof, the collapse of which can damage both the structure and household members. Therefore, in this article we will present methods for calculating the optimal angle of inclination of the slope.

IN residential buildings There are four main types of roofs that can be used. Single-pitch option Suitable for an extension or outbuilding, but does not look at all on the main building. The only real plus of this type- This minimum consumption roofing material, but there may be safety issues. Almost all the fallen snow is retained on the flat slope, so such roofs are cleaned manually by climbing onto the slope.

A gable roof does not require the construction of a complex frame

The gable version, built on the basis of two slopes, allows you to create a safe roof from which snow caps of any thickness will come off. Besides, gable roof it looks very presentable and does not require the construction of a complex frame. The hip variant and its derivatives are hipped design with a complex frame and relatively low consumption of roofing material. Not all specialists are capable of building such a structure - the abundance of joints (especially in the attic or half-hip version) requires more skill and time to assemble the roof. After all, in case of an error, it will flow, flooding a residential building.

The multi-gable option is a multi-slope design complex shape. This option can only be built by experienced roofers. A multi-gable roof requires more building materials and time, making this option the most expensive option available. Moreover, a complicated shape (such a roof has five or more slopes) can both decorate and overload the exterior of a home, creating a feeling of excessive complexity, evoking feeling irritation in people with fine architectural taste.

And if you choose according to the ratio of the simplicity of the design and the calculations carried out, the volume of building materials used and the presentability of the exterior, then the best option there will be a gable roof with two slopes. It is this design that we will consider when trying to understand how to calculate the angle of inclination of the roof for a country house or cottage.

Before calculating the optimal roof geometry, you should become familiar with roof design to understand the process and terminology involved. This will not take much time, since the option we have chosen consists of 7 original elements:

1. 1. Mauerlat – logs at the base of the frame, which are laid on a load-bearing wall.
2. 2. Ridge - the upper edge of the roof. In our case, this is not exactly a detail, but a place where the roof slopes meet.
3. 3. Beams - beams under the ridge of the roof, laid at the same level as the mauerlat.
4. 4. Racks – vertical beam, connecting the bed and ridge run(beam under the top edge).
5. 5. Rafters - beams resting on the mauerlat and ridge girder of the roof.
6. 6. Lathing - alternating longitudinal slats laid on top of the rafters and forming the basis of the frame for the roof slope.
7. 7. Strut - a beam laid at right angles to the rafters and stretched to the point where the post and the beam meet.

At the base of the frame there are logs that are placed on load-bearing walls(mauerlat)

The total number of elements depends on their functional purpose. For example, there is always one bed near the roof, and at least two for the mauerlat. The number of rafters is always paired and equal to the number of struts. Well, the number of racks is determined by dividing the sum of the rafters by two. After all, for every couple rafter legs there is only one stand. And now about the most important thing - the roof angles we calculate are formed by the plane of the base (horizontal) and the line of the rafters laid at an angle to the mauerlat.

Technically, the slope of the roof can vary from 0 to 90 degrees. In the first case, we will get a flat roof, and in the second, a pitched roof (the second slope should be less than 90°).

Snow load is an important factor in determining the roof pitch

The geometry of the roof with two slopes and angles differs from the limit values, but cannot be any; the possible value of the slope of the rafters is determined under the influence of the following factors:

• Wind and snow load. The correct slope should help save on frame construction. After all, the higher the load, the more rafters, racks and struts will be needed.
• Type of roofing. Each variety construction material roofing imposes restrictions on the minimum and maximum values ​​of the calculated angle.
• Cost of building materials - the lower the slope, the cheaper the structure. After all, if the roof slope is zero, then the area of ​​the slope is equal to the dimensions of the roofing. And as the slope increases, the area of ​​the slope also increases. And if you have chosen an expensive building material, then the correct slope will help you save on its purchase.
• The dimensions of the structure itself - the height of the ridge should correspond to the distance between the mauerlats. Otherwise, you will get distorted proportions and ruin the aesthetics of the house's exterior.

Moreover, all the factors mentioned above are interrelated, so they are considered only as a whole when calculating the optimal roof geometry. How to do it? We will talk about this below in the text.

The optimal angle of inclination of a gable roof should not lead to an increase in snow and wind loads, distort the exterior of the house and force the purchase of more roofing and building material. Therefore, to determine its value, we will sequentially move through all the mentioned parameters, selecting optimal size for each of them. After which we will calculate the slope based on the average value and acceptable limits for the roofing material.

The most optimal angle of inclination of a gable roof is about 37 degrees

For wind load optimal slope– this is 0 degrees. In this case, it does not add height to the building. Therefore everything multi-story houses have a flat roof. In addition, zero slope gives minimum area stingray In this case, it is equal to the area of ​​the ceiling (ceiling or floor). For snow loads, the optimal angle is 60 degrees. Roofs with such angles do not accumulate snow on the slopes, which makes it possible to ignore snow load as such. As a result, the average slope in snow and wind is 30 degrees ((0+60)/2). This value lies beyond the threshold value (25 degrees), which allows reducing the calculated snow load by 30 percent and does not increase the wind load.

The optimal exterior gives the ratio of the height of the rack and the distance between the mauerlat and the floor in the proportions of 3:4 or 1:1 (in the case of an exploited roof). That is, the tangent of the slope angle in this case will be equal to 0.75 (3/4) or 1.0 (1/1), which corresponds to angles of 37 and 45 degrees. The average angle for the exterior and wind/snow load is 37.5 degrees ((30+45)/2), which corresponds to the optimal proportion of 3:4 (the ratio between the height of the ridge and half the width of the building on the gable side).

That is, the optimal slope angle should be as close as possible to 37 degrees. Moreover, in snowy regions it can be closer to 45 or even 50°, and in southern regions– reduce to 30°. After all, snowy and wind load even in middle lane Russia have a ratio of 4:1. On average, about 200-210 kilograms of snow or the equivalent of 35-40 kilograms of wind presses per square meter of roofing structure. Therefore, counteracting snow in our latitudes will be more relevant.

From the point of view of roofing materials, an angle of 37° allows the use of such varieties as two-layer roofing felt (roofing felt), galvanized seams, tongue-and-groove tiles, and slate when arranging the roof.

As you can see, at this angle you can choose a material to suit every taste and budget. From the position rational use space, this angle is also beneficial due to the fact that an attic equipped inside the roof will give at least 4 square meters usable area for every meter of length of the bed, and the area outer covering will fluctuate within 13 m 2 per meter of ridge length. That is, 37° will also be beneficial from an economic point of view.