The optimal angle of inclination of a gable roof. Roof Pitch What should be the minimum slope of a tiled roof?

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The foundation and the roof are the two most important and complex architectural elements of any building. Roof load-bearing elements rafter system, and its performance largely depends on the angle of inclination of the slopes. Ordinary developers choose the optimal roof slope based on criteria other than designers.

They are not entirely interested in calculations for the strength of bearing nodes, they are of little interest in the influence of the angle of inclination gable roof on the cost and complexity of the truss system, etc.

What do ordinary developers pay attention to?

Roof Angle Options	Short description
	Every owner wants to have beautiful house with their individual differences. On the outside of the house big influence renders the angle of inclination of the slopes. Architects have their own requirements for buildings, houses must organically fit into the style of existing buildings. This parameter is especially strictly applied when the house is located within the city. Quite often, local governments make decisions prohibiting the violation of the traditional architectural appearance. It is impossible, for example, to build a house with a roof slope of 45 °, if all the buildings on this street have a slope of no more than 20 °.
	This factor has very little effect on the optimum angle. Roofing materials have only general recommendations for installation on flat and sloping roofs. Flat roofs have a slope angle of less than 10°, all structures with a slope angle exceeding these values are considered sloped. The technology of installation of roofing materials with an angle of inclination of 15 ° is no different from the technology roofing works on slopes with a slope of 45 °. There is, however, a limitation for piece tiles, it can be installed on roofs with an inclination angle of at least 22 °.
	The greater the angle of inclination of the slopes, the higher the attic space. Such roofs are built for buildings with attics. Developers pay great attention to this factor, but not everything is as simple as it might seem at first glance.

These wishes are taken into account by architects during the design and calculation of elements of roof systems. But a fairly large number of purely engineering factors are added to them, which have a decisive influence during the calculation of the parameters of the truss system. And the angle of inclination of the slopes is not the only one among them, all values depend on each other and cannot be ignored when developing a project.

How designers choose the optimal angle

Calculations are made on the basis of SNiP 2.01.07-85. Placed norms are used during calculations taking into account permanent, temporary and special loads and their various combinations.

SNiP 2.01.07-85. The PDF file will open in a new tab

What loads are taken into account when determining the angle of the roof

Loads are divided into several categories depending on the duration of their impact: long-term, short-term and special.

Long-term (permanent) loads on the truss system. These include the weight of roofing materials, insulation, wooden elements of the roof structure. This category should include loads arising from thermal expansions and changes linear dimensions due to changes in the relative humidity of lumber. Regulatory temperature changes are determined by formulas separately for heated and unheated premises. The weight of the snow cover is also considered a long-term load on the rafter system and must be taken into account when determining the optimal angle of inclination. rafter legs.
short-term. The rafter system is influenced by the weight of workers, stored building materials, the mass of special equipment and tools used during construction, and wind loads.
Special loads. Efforts arising during natural disasters, earthquakes, explosions, with a sharp loss bearing capacity one or more loaded nodes of the truss system.
Special loads include earthquakes and natural disasters

When determining the angle of inclination of the roof, the maximum possible combination of loads is taken into account. Both of these parameters affect the thickness and length of the rafter legs. The calculation of the truss system and the angle of inclination of the slopes is done according to the limit states, taking into account all adverse factors.

The maximum deflections and movement of the rafter legs are regulated regardless of their linear dimensions and should not lead to partial depressurization of the roof. For all types of roofs, regardless of the angle of inclination, the following conditions are put forward:

the safe operation of buildings must be guaranteed;
structural integrity cannot be compromised even during short-term peak loads;
the appearance of the roof should not change the entire period of operation.

Moreover, each requirement must be fulfilled independently of the others. The limit values for the deflection of the rafters are limited taking into account the operational characteristics of the roofing materials. If the standard values do not have a noticeable effect on the appearance, then they are not adjusted.

Practical advice. It is much easier to ensure the integrity of the roofing pie of the roof not by increasing the strength of the truss system, but by using special structural compensators.

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. It 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 school 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 gable roof Houses. 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 a unique design of the facade 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. The complex design is offset by the spectacular appearance of the roof 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:

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.
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.
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.
For roofs covered with metal tiles, the minimum angle is 14 degrees.
For roofs covered with onduline, the minimum angle is 6 degrees.
For soft tiles 11 degrees is considered a small angle, and regardless of the selected angle, there is required condition- installation of a continuous crate.
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 question of how to calculate the angle of inclination of a roof with a shed design is a difficult task for those craftsmen who are just starting to learn the basics of roofing. This is due to the selection of parameters that determine the difference in the design of the roof. Consider its main components:

rafter system and additional accessories;
crate;
roof threshold from layers of thermal insulation, waterproofing and vapor barrier;
roofing material.

It should be borne in mind that a large angle of inclination will require the use of a significantly larger amount building materials, thereby increasing the cost of building a roof up to 20%. When building in regions with a large wind load, use the design shed roof with a slight angle of inclination, which in most cases is located to the windward side. This provides significant resistance to wind loads. For this reason, a competent calculation of the angle of inclination contributes to a high level of savings in roofing materials, subject to all building codes and regulations. The determining factors in this are:

climatic features of the area in which construction is carried out;
roofing material;
purpose of the building.

The dependence of the angle of inclination on the type of roofing material

When choosing a roofing material, it should be borne in mind that it has a direct impact on the structure being built and its cost. The calculation of the angle of inclination of the slopes should be carried out taking into account the type of roofing material. For this, it is recommended to use the table below.

The table shows that the roofing material is the determining factor in the implementation of the calculations.

When using a soft roof, the angle of inclination is much smaller compared to slate.

The calculation should also take into account the atmospheric features of the area where the construction takes place. One of the features of roofs with an angle of inclination of 300 is the accumulation of snow on the leeward side and an increase in the load on roofing materials, and truss system.

Formula for the correct calculation of the required parameters

Since a shed roof rests on walls with different heights, the angle of inclination is formed during the construction of walls with different levels of height. In construction documentation, it is allowed to accept the angle of inclination in the range from 5 to 60 °. For areas with increased precipitation in the winter season, the calculated value lies in the range from 45 to 60°. When calculating the angle of inclination of the slopes, the load of atmospheric precipitation is taken into account, which is associated with the design features of shed roofs and the mechanical strength of roofing materials. In general, the formula has the following form:

where L of the wall is the height of the pediment of the wall;

L length - the length of the wall of the house;

A is the angle of inclination.

For building one pitched roof you should calculate the length of the rafters, which is determined by the following formula:

To find sinA and tgA, use the special tables below:

Calculation example

House wall length: L length =5 meters;

Roof pitch: A=25°;

Let's determine the height of the wall: L walls \u003d 5 × tg25 ° \u003d 5 × 0.47 \u003d 2.35 meters;

Determine the length of the rafters: L rafters =2.35÷sin25°=2.35÷0.42=5.6 meters.

To obtain reliable calculation results, add the length of the front and rear overhang to the length of the rafter leg. They will serve optimal protection houses from precipitation.

Competent calculation of the roof is associated with the aesthetic appearance that it will have as a result of the completion of construction. Most owners of modern homes prefer high roofs, which give the building a slender, classic look. Another advantage is the possibility of arranging a spacious attic. But, from a financial point of view, the construction of a flat roof is much cheaper than its pointed counterparts.

Advantages of a pitched roof

A shed roof has many advantages that make it the most popular option for arranging residential buildings and structures. Its main advantages include:

simple design;
the construction of a shed roof requires significantly less building materials than its other varieties;
simple and easy installation;
low construction cost;
high resistance to wind loads;
short construction time.

Disadvantages of a shed roof structure

In addition to the advantages, the shed roof has the following disadvantages:

during its construction there is no possibility to equip a comfortable attic; it's connected with design features roofing;
reduced level of thermal insulation, which is due to the minimum amount of free space under the roof.

The calculation of the angle of the roof slope allows even at the preliminary preparatory stage get reliable data on the amount of materials needed for the construction of a pitched roof. The use of the correct methodology for obtaining calculated data provides the optimal ratio between the cost of erecting a roof and its operational characteristics. To save financial resources during construction, it is not at all necessary to reduce the reliability of the roof or refuse to use high-quality materials. It is important to carry out a competent and correct calculation in a timely manner, which will reflect the true cost of construction.

Calculation of the angle of inclination of a shed roof. Learn how to find the slope of a shed roof using the formula for calculating the angle of inclination

We determine the optimal and minimum slope of a pitched roof

Roofs with one slope are in vogue. There are many reasons for this, including their practicality, low cost and characteristic appearance. The slope of shed roofs in most cases differs from gable and hip roofs: it is smaller. Consider what determines the optimal and what limits the minimum slope of a shed roof.

What the norms say: we study SNiP “Roofs”

The updated version of SNiP II-26-76 "Roofs", updated within the framework of SP 17.13330.2011, states that the slope of a flat roof should be from 2 ° to 12 °. It is logical to assume that the norms assume a value for a pitched roof over 12 °. However, SNiP does not contain any information about the slope of the pitched roof. The value of 12 degrees is optional. In fact, the border between a flat and a pitched roof is not fixed by regulation and is often determined “by eye”.

One of the factors indicating that the roof is shed is the use of roofing material on it intended for pitched roofs (all types of tiles, sheet materials, corrugated board, etc.). Flat roofs have an average slope of 3° and are covered, with rare exceptions, with rolled bituminous materials. rolled bitumen roof successfully can be arranged on pitched roofs.

Determine the optimal angle of inclination

The optimal slope of a shed roof is dictated by the architectural and planning features of the building. With the same slope as a gable roof, the ridge of a single-pitched roof will turn out to be twice as high, so single-pitched roofs are more gentle. For a barn, garage, veranda, in most cases, 10-15 ° will be enough. A shed roof is economical, especially for small buildings. As a rule, a slope of 10-15 ° is sufficient.

A shed roof is of little use for organizing an attic in a classic form: one part of the room will turn out to be too low, the other too high, it is difficult to use such a volume rationally. Even with the construction of the attic floor, it is hardly worth making a slope of more than 30 °. A non-attic shed roof, relatively sloping (10-20 °) allows you to equip rooms with different ceiling heights on the floor. Living rooms are taken out to the higher part, bathrooms, utility rooms, stairs to the lower part.

If the layout provides for levels of floors shifted along the marks, a steep shed roof with a slope of 20-35 ° will be rational.

Calculate the minimum slope

The limiting factor for the minimum and maximum slope is the manufacturer's recommendations for specific types of roofing materials. Shed roofs are quite flat, we will be more interested in the minimum values.

The rolled built-up bituminous roofing allows you to cover any roofs, including flat ones. Only the maximum angle of 25° is limited, although it is better not to go beyond 15° in order not to complicate the installation. The most durable and reliable bitumen-polymer materials, the top layer is sprinkled with stone chips. Roll materials are glued to bituminous mastic hot way.

Asbestos-cement corrugated sheets (slate) require a rather large slope. For reinforced profile sheets, it must be at least 25 °, for a regular profile - 35 °. It should be noted that the overlap of the sheets of the upper row is taken depending on this value. The higher it is, the more overlap.

The so-called "Euro-slate" is less demanding on the steepness of the surface, a minimum of 6 ° is allowed. When installing bituminous corrugated sheets, not only the amount of overlap, but also the design of the crate depends on the slope: at 6-10 ° it should be continuous, at 10-15 ° a step of bars or boards of 45 cm along the axes is taken, with a larger value, 60 cm is sufficient.

Metal tiles can theoretically be laid with a slope of 10°. But with a parameter of 10-20 °, all the joints of the sheets will have to be sealed, and this is not an easy task. rational decision there will be the use of metal tiles for roofs with a slope of more than 20 ° without additional sealing.

The corrugated board can serve as a roof covering for roofs with a slope of 5 °. At 10 °, the overlap is increased, a sealing tape is laid at the joints.

Seam roofing, both from standard elements with a factory seam, and in the manufacture of a seam on galvanized steel sheets directly on the construction site, is used for bases with a slope of 8 °. Under the condition of sealing seam joints, the value can be reduced to 3 °.

Bituminous shingles are used for slopes of at least 11°. At a value of up to 18 °, the lining layer must be continuous, with a larger value, it is enough to roll the rolls only along the outer contours of each of the roofing planes and additionally isolate the holes.

Ceramic and concrete tiles require a slope of 22°. It can be reduced to 10° if an additional waterproofing layer is placed under the tiles. Tiles are quite heavy and are rarely used for shed roofs.

The data provided is not completely accurate. Each manufacturer of roofing materials sets its own requirements, they may vary slightly. In addition, the slope largely depends on the snow load for a particular area. The less snow, the flatter the roof can be. There are territorial standards that set the minimum depending on the climatic features of the area.

We have found that the angle of the shed roof is determined by the architecture of the building and is limited by technical requirements. The calculation of the truss system to ensure the necessary strength with a rational consumption of materials should be entrusted to specialists.

We calculate the minimum angle of inclination of a pitched roof for an optimal result

The angle of inclination of a shed roof is much lower than that of a gable roof. What are the design factors that limit the minimum slope

Features of calculating the angle of inclination of a pitched roof

The shed roof has gained considerable popularity due to the relative ease of installation and financial profitability. This type of roof is becoming a frequent choice in the construction country houses. With a shed roof, you can reliably protect the building from the wind and negative impact other weather phenomena, if the angle of inclination of the shed roof with respect to the windy side is correctly calculated.

A shed roof will last longer and will more reliably protect the building from the effects of weather conditions if its rafters rest on walls of different heights, and they will be less affected by gusts of wind.

According to experts, even a person without special skills can install a pitched roof. They argue that it is enough to observe all the necessary security measures and theoretically familiarize yourself with the features of the progress of the work. This ease of installation and the minimum amount of materials used are the primary advantages that attract many consumers who build vacation homes today.

For maximum safety, when installing a shed roof, you should use the most reliable ladders and remember to wear rescue harnesses.

The design features of a pitched roof make it possible to completely avoid

An example of calculating the angle of inclination of a shed roof

irrational use of space in the room. Shed roofing does not provide for the presence of an attic and few comfortable attics.

In addition to summer cottages, shed roofs are equipped with garages, sheds, outbuildings for various purposes, and quite often residential buildings. In residential buildings, roofing of this kind helps to create a more unique design of the room. Also, often the equipment of a shed roof in a residential building requires the characteristics of the area. Thus, it is possible to minimize the amount of rainwater and melted snow flowing onto the roadway.

Varieties of pitched roofs

Depending on whether roof ventilation is provided in the room, two types of shed roofs are distinguished:

Ventilated. Usually used in the construction of buildings of a closed type. The angle of inclination of a shed roof in this case ranges from 5 to 20%. Ventilation is a void specially allocated for the passage of air between the waterproofing and heat-insulating layer of the roof. This allows you to significantly increase the life of the roof of the building.

When installing a shed roof with the provided ventilation system, it is necessary to make holes on the sides of the building at the level of the roof. This will ensure constant air exchange, regardless of wind direction.

Not ventilated. Most often used in the construction of terraces. The angle of inclination in this case is in the range of 3-6%. The open type of the room requires special care, especially in winter.

There is also a combined version of shed roofs with and without ventilation. In this case, thermal insulation provides a slight slope of the pitched roof. At the same time, there is a significant saving in the creation of the structure, but they create certain inconveniences during operation. So, in winter, with a large amount of snow that has fallen, it is necessary to constantly clean the roof, reducing the load on it.

What are the advantages of pitched roofs?

In addition to the minimum amount of materials used and the ease of installation, as mentioned earlier, there are a number of other advantages due to which a shed roof is chosen during the construction of buildings for various purposes.

If wood is a scarce material in the region where the building is planned to be erected, a shed roof will be the most financially advantageous option for the developer. Its installation involves the use of a minimum of wood.
The minimum slope of a single-pitched roof significantly reduces the windage index. Thus, the space of the room under the roof will be used most rationally, it will not be necessary to equip the least comfortable and little functional attic.
This type of roof can be easily used in commercial buildings with walls of different heights.
If there is a roadway on one side of the building, a shed roof will avoid dumping large amounts of snow and rainwater onto the road.

To eliminate the possibility of damage to the roof by gusts strong wind, it is necessary to install a special curb on the waste side, reinforced with galvanized iron or tiles.

Rafter system for shed roofs

The roof truss system is, in fact, its skeleton. That is why its primary task is to evenly distribute the mass of the material of the roof itself on the supports on which it is attached. Also, when forming the truss system, one should take into account the force of the impact of winds and precipitation in a given area.

It is imperative to increase the indicator of the expected load on the truss system, calculating it, as they say, with a margin.

When developing a shed roof, one should take into account the plan of the walls that act as a support, the characteristics of the ceiling of the attic and interior partitions, external parameters of the building, as well as the distance of the largest span.

The angle of the roof and the ease of its installation depends on the type of attachment of the truss system to the supports. So, there are three types of attachment:

Hanging rafters are used if it is not possible to provide support for the rafters in the distance between the side supports. In this case, the assembly of trusses takes place on the ground, and then the finished structures are carefully transferred to the extreme supports. This process takes the most time and effort. Complicates its presence of large spans. The load-bearing elements of the roof are usually made of softwood, metal and reinforced concrete. The most suitable section of the rafters is 5 * 15 centimeters. The bars for the crate should be characterized by a cross section of 5 * 5 sentiments.

Inclined rafters suggest support on the outer walls of the leading elements at an angle. In the upper part of this type of rafter, they rest on a beam fixed with struts and racks. Partitions act as a support for the struts. Also, external bearing walls. The length of the distance between the truss systems can vary between 60 and 140 centimeters. This distance depends on the thickness of the tree and the parameters of the material used for the roof. The support for the structure are walls, characterized by different heights. Most often, inclined rafters are selected when arranging the roof of utility buildings.

Do not forget about turning the slope of the roof relative to the windy side.

Sliding rafters use a log in the ridge as a support. When connecting the rafters to the walls, in this case, special elements called "sliders" are used. Sliding rafters are most often used in the arrangement of roofs in log buildings. Thanks to the use of this type of rafters, it is possible to compensate for the rather large shrinkage of the log house, preventing damage to the building at the junctions of its main elements.

Materials used in the formation of pitched roofs

When wondering how to determine the angle of inclination of the roof, it is first necessary to take into account the material from which the roof is planned to be created. So, there are certain limits for the permissible slope for different types roofing material:

The slope of the corrugated roof can vary from 8 to 20 degrees.
If a metal tile is chosen as the material for the roof, its minimum slope can be 25 degrees.
For a slate roof, the minimum slope angle increases to 35 degrees.
Seam roof can be at an angle in the range of 18-35 degrees.

Do not try to make the angle of inclination less than eight degrees, since such a roof can fail even under the weight of snow with a high level of precipitation.

Once the most suitable roof angle for a particular building has been determined, it will be necessary to raise the facade wall of the building so that its height in relation to the back wall forms a set slope. In such calculations, it is simply impossible to do without the use of certain trigonometric formulas, therefore, often for correct calculations, you should contact experienced specialists in drafting projects of a similar plan.

Shed roof slope angle: minimum and optimal roof slope - how to calculate?

The article angle of inclination of a pitched roof will tell you how to calculate the angle of inclination of the roof, which angles of inclination are minimum and optimal for various kinds roof coverings, as well as calculation examples and factors influencing the choice and calculation of the roof angle.

How to correctly calculate the angle of inclination and height of a shed roof

Throughout the globe, there are thousands and thousands of architectural traditions in terms of appearance roofs But modern architects have completely changed the idea of culture. suburban construction, introducing shed roof shapes as ideally combined with landscape design and varied in performance. Of course, this new fashionable tone was set by the inhabitants of Australia, where the absence of snow in general as a natural phenomenon allows them to create everything that fantasy dictates with the architecture of residential buildings. But in the snowy regions of Russia, such a roof can be built, but with an appropriate slope and in the right direction. In a word, the main parameter of functionality is the angle of inclination of a shed roof, which we will now teach you to calculate.

Step 1. Calculate permanent and dynamic loads

First of all, calculate the loads on the shed roof. They are usually divided into permanent and dynamic. The first is the weight of the roofing that is always on the roof, installations such as antennas and dishes, a chimney, and so on. Those. everything that will be on the roof day and night.

And dynamic loads, or, as they are also called, variables, are those that happen from time to time: snow, hail, people, repair materials and tools. And also the wind, which, well, loves to tear off pitched roofs due to their windage.

Snow loads

So, if you make a pitched roof slope of 30 °, in winter the snow will press on it with a force of 50 kg for each square meter. Just imagine that on your roof there will be one person per meter! Here is such a load.

And if you raise the roof to above 45 °, the snow will most likely not be able to linger at all (it also depends on the roughness of the roofing). But for middle lane In Russia, where snowfalls are moderate, it is enough to make a shed roof within 35-30 °:

The minimum angle that must be in order for the snow to be able to descend from the shed roof itself is 10 °. And the maximum is 60 °, because it makes no sense to make the roof steeper. The same applies to snow, which clings even more to such a roof.

That is why the owners of shed outbuildings often take up a shovel in winter. Only the coverage area saves: the smaller it is, the less likely it is that the snow will be able to bend the material.

Wind loads

But in windy regions, it is impossible to build roofs with steep slopes at all. For comparison, a shed roof slope of 11° experiences exactly 5 times more wind force than a 45° slope. In view of this, please note that a shed roof is always made with a low part to the leeward side.

Combined loads

And be sure to calculate for a shed roof such a value as a combination of the most unfavorable permanent and temporary loads. Those. the critical point that the truss system must be able to withstand. By the way, this is often forgotten! They think that the roof will withstand the snow, the wind too ...

But what if you and your friend have to climb onto the roof in a strong storm and snowfall? Is the structure designed to withstand the snow, the wind, and the feet of at least two people at the same time? This is how trouble happens.

Step 2. We select the slope of the roof

Shed roof slope - in a fairly wide range: from 6 ° to 60 °. It all depends on the terrain in which you are going to build: if you need to successfully dump tons of snow every winter, then make the slope steeper, if you plan to protect yourself from the wind, then more gentle. And from many other factors, including aesthetic ones.

Steep pitched roofs

The larger the angle of such a roof, the faster water flows down it into the gutters. Neither leaves nor dirt will linger here, and therefore the roofing itself will last much longer. In addition, on such a roof, the visual aesthetics of the chosen shingles or a metal profile, which often plays a big role for the owners.

Sloped shed roofs

The speed of flowing rain and melt water on low-slope slopes is much lower, and therefore there is a risk of stagnant water, collecting dirt and ice getting stuck. On such roofs, moss quickly develops and foliage sticks. Especially if the roofing is rough.

As for rainwater, the main requirement for the roof is that the water on it, when snow melts or after rain, does not remain on the surface of the roofing material, but easily rolls off. If it has a too low slope (for a certain area), then the liquid will stand for a long time in all bumps and seams. And the longer - the more chances she has to get inside and create many problems in the form of dampness, deteriorated insulation and corrosion of the metal elements of the roof:

But, if a large roof of the house rises above such a building, then it's okay:

But there is still a plus here: the smaller the angle of inclination of a shed roof, the closer the geometry interior spaces to the traditional cube. And, therefore, it is perceived easier and used with greater benefit.

Therefore, the lower the angle of inclination of such a roof, the more it is necessary to take care of its waterproofing so that melt and rainwater cannot penetrate the rafter system. Therefore, roofing materials such as membranes, rolled insulation or solid sheets are already needed here.

With a standard angle of inclination, a pitched roof is built as follows:

Minimum angle of pitched roof

A shed roof, the angle of which is only 3-5%, is often made inverted. Those. subject it to certain additional loads: walk on it, grow a garden on it, or even use it as an open terrace. Like here:

In addition, at a certain angle, a shed roof directs the air flow in the right direction, capturing precipitation and diverting it. Remember this!

Step 3. Decide on the slope requirements

In functional terms, shed roofs are divided into three main types: ventilated, non-ventilated and combined. Let's consider each option in more detail.

Ventilated design

These are equipped in buildings of a closed type. As ventilation, there are air vents and special voids between the insulating layers, through which the air, passing through, captures moisture droplets from the insulation and carries them out.

If such ventilation is not provided, then moisture will remain inside the insulation (and it still gets into it, albeit a little), and the insulation will begin to dampen and deteriorate. And as a result, the entire roofing pie will gradually collapse.

But a ventilated shed roof has its limitations. So, the angle of inclination for it can only be in the range from 5% to 20%, otherwise the air will not be able to effectively pass through the vents.

Non-ventilated design

This type of pitched roof is built on terraces and outbuildings. Typically, the angle of such a roof is in the range of only 3-6%, although there are no restrictions on it.

Ventilation in such roofs is not needed because the air in a room without walls or with wide doors often open (as is the case with a garage) itself ventilates well, carrying any water vapor outside. Which, by the way, by themselves are not particularly formed in such buildings:

Combined design

Such roofs combine the device of both previous types. Here, the desired slope of the roof is given by thermal insulation. It turns out economically, but in winter you will have to constantly clean off the snow.

But the arrangement of such a shed roof is already different, because dynamic loads are now added to variable and static loads. And usually everything looks like this: corrugated board below, on it - two layers of insulation and good waterproofing.

The angle of the shed roof also depends on such parameters as the type of connection of the rafters to the Mauerlat or walls. Let's take a closer look.

Step 4. Calculate the exact slope angle

The angle of a shed roof is called the angle at which the rafters and the slope of the roof are inclined to the horizontal plane of the ceiling. And take this scheme seriously if you want to provide your roof with the correct mechanical strength:

The angle of inclination of the slopes is measured in percent and degrees. But, if degrees are even more or less clear (thanks to the school geometry course), then what are percentages? Percentage is the ratio of the difference in the height of the ridge and the cornice to the horizontal of the slope, multiplied by 100.

There is another interesting point: many architects specifically calculate the angle of a shed roof so that it is equal to the angle of elevation of the sun in a given area in the middle of spring. Then it is possible to calculate to the millimeter when and what kind of shadow will be, which is important for planning terraces in front of the house and other places of recreation.

Step 5. We limit the circle of choice of roofing

Modern roofing materials also have their own requirements for the minimum and maximum angle of inclination of a pitched roof:

Decking: min 8°- max 20°.
Seam roof: min 18°- max 30°.
Slate: min 20°- max 50°.
Soft roof: min 5°- max 20°.
Metal tile: min 30° - max 35°.

Of course, the smaller the angle, the cheaper materials you can use: roofing material, corrugated board and the like.

You will be surprised, but today the same types of roofing are being developed specifically for low-slope roofs that are usually used with a slope of at least 30 °. For what? Such is the fashion in Germany, which has come down to us: a shed roof is almost flat, and the roof is stylish. But how? It's just that manufacturers improve the quality of the locks, make the overlap area larger and think over the protection against dirt more carefully. That's all the tricks.

Step 6. We decide on the truss system

And from the chosen angle of inclination of the roof and the loads planned for it, we determine the type of fastening of the rafters to the walls. So, there are three types: hanging rafters, layered and sliding.

hanging rafters

Hanging rafters are the only option when the connection must be rigid, but there is no way for the rafters to be supported between the side supports.

Simply put, you only have external load-bearing walls, and no partitions inside. Let's say this is a rather complex truss system, and its construction must be approached with responsibility. The whole problem is in large spans and in the pressure that is exerted on the walls:

Or like in this project:

Rafters

Here, the entire roof is already pressing on at least three supports: two external walls and one internal. And the rafters themselves are used here dense, with a section of at least 5x5 cm of bars and 5x15 cm of rafter legs.

sliding rafters

In this rafter system, a log in a ridge serves as one of the supports. And to connect the rafters with it, such special elements as "sliders" are used. These are metal elements that help the rafters move forward a little when the walls shrink to avoid cracks. Very little! And thanks to this device, the roof easily tolerates even a fairly noticeable shrinkage of the log house, without any damage.

The bottom line is simple: the more nodes in the truss system, the more flexible and durable it is. The more a shed roof is able to withstand the pressure of the weight of the roofing and snow, and at the same time not break. But there are truss systems where the connection is generally static:

Step 7 Calculate the Height of a Shed Roof

Here are three of the most popular ways to accurately calculate the desired height of the future roof.

Method number 1. Geometric

Shed roof has the form of a rectangular triangle. The length of the rafter leg in this triangle is the hypotenuse. And, as you remember from school course geometry, the length of the hypotenuse is equal to the root of the sum of the squares of the legs.

Method number 2. trigometric

Another option for calculating the length of the rafter legs is this:

Let A be the length of the rafters.
Let B denote the length of the rafters from the wall to the ridge, or the length of the part of the wall in this area (if the walls of your building are of different heights).
Let X be the length of the rafters from the ridge to the edge of the opposite wall.

In this case, B \u003d A * tgY, where Y is the angle of the roof, and the length of the slope is calculated as follows:

In fact, all this is not difficult - just substitute the desired values, and you will get all the parameters of the future roof.

Method number 3. Online calculators

By the way, modern online calculators will also help to calculate the required angle of a pitched roof. Usually they are adjusted to the current SNiPs - "Load and Impact" TCP 45-5.05. But this method can only be used as an additional one.

Calculated? And now we turn to the construction of the roof itself:

We hope you understand everything easily!

The angle of inclination, height and slope of a shed roof: how to calculate

Simple step by step instructions, convenient tables and clear calculation schemes. A step-by-step guide to calculating the angle of inclination of a shed roof.

The construction of the roof is one of the important stages of construction. The roof protects the home and performs an aesthetic function, making the design of the building complete. Choice suitable material- not the only significant nuance. It is also necessary to correctly calculate the slope of the roof. This article will tell you how to do this.

Peculiarities

IN modern projects country mansions take into account a large number of requirements. Performers are forced not only to comply with the norms, but also to implement the wishes and whims of customers. However, regulatory requirements are still in the foreground, because the roof, first of all, must be reliable. Therefore, often architectural delights fade into the background.

Roofing should fulfill its intended purpose - to protect against moisture. In some cases, thermal and sound insulation is required. This may be necessary to increase the functionality of the premises under the roof. Therefore, the design of the roof can not be called a simple matter. This work requires extreme responsibility, especially if the customer insists on a complex configuration. IN different situations professionals use a variety of techniques. Calculations are made using the appropriate software.

The theory of calculations may be of interest to the owner of the house. For example, such knowledge makes it possible to check whether professionals have applied the correct methodology. They also help to correctly present their author's ideas. In addition, the calculated parameters make it possible to determine the required amount of building materials for both the truss system and the roofing.

The peculiarities of the calculations are that professionals use different values for measurements. For example, not everyone measures the slope angle in degrees. In the usual everyday life of some masters, there are such concepts as a percentage or relative aspect ratio. You also need to know what is taken as the angle of the roof.

The angle of inclination of the roof is formed by the intersection of two parameters:

one horizontal plane;
one flat roof slope.

This parameter is measured from the top edge to the base of the truss system. When calculating, only acute angles are taken into account, since there are no obtuse-angled slopes by definition. Steep slopes are rare. Typically, they are used for decorative design(for example, when building turrets in the Gothic style).

Roofs can be steep attic view. In this case, the lower rafters are placed at a very large angle. On ordinary roofs, slopes up to 45 degrees are mounted.

For a better idea of how it should look, you can take a protractor and look at the divisions indicating degrees.

The value of the oblique angle is calculated as the ratio of the parameters of the ridge to half the width of the structure, multiplied by 100. Most professional builders use the so-called tabular graphs. Depending on the indicators, roofs are usually divided into types.

Kinds

Experts distinguish several main types of roofs.

Single roof. In this case, the roof looks like a flat plane. It has distinctive height parameters.

Double roof. It is a reliable, easy-to-install option. The roof includes two slopes connected at a right angle.

Hip roof. It is supplied with four slopes, two of which are triangles, and two more are trapezoids. The top of such a roof looks cut off. Despite the complexity of the design, such roofs are very economical in terms of material consumption.

Vaulted type of roof. It is rare, as it involves a limited choice of materials. Such options are built only from brick or stone. The rarity of the choice in favor of such roofs is also due to their heaviness. In small private construction, this type is practically not used.

Multi-gable type of roof. It is complex in configuration, but very beautiful. Such a roof is difficult to lay due to the many junctions and lintels.

Also, experts identify types of roofing that can be subsequently exploited., and options that are not subject to exploitation. If professionals classify the roof as unexploited, this means that there is practically no space between the roof itself and the upper floor. This territory can be used, but only as a technical one. For example, this is a low-slope pitched roof.

Shed roofs the most favorable for construction. They require a minimum of material costs, but the work can be done independently. If the roof has a slight slope, then on its surface it is possible to realize a place of rest without constructing a complex attic.

The space under the roof can be used if the type of roof is pitched. The attic area can be used for economic needs. Also due to it, you can expand the living space.

The choice of this or that type of a roof is connected with many nuances. One of the main ones is the climatic factor.

Climate influence

For example, a huge load on roof structure may be due to wind. Even a slight increase in the slope angle increases the wind load. For example, if the angle of inclination of the roof is 30 degrees more than the standard values, the wind load becomes five times greater. Therefore, even a slight increase in performance can play a cruel joke on the owner of the house during a natural disaster.

No less destructive effect on the quality of the roof precipitation. At the same time, a well-chosen slightly larger slope will avoid the accumulation of snow on the surface. There will be no snow melting at all with a roof slope of 30 degrees. And with a slope of 45 degrees, the normative indicators for the snow load on the roof will be observed.

In northern countries (Sweden, Finland, Norway, etc.) it is customary to make very high pitched roofs. It is obvious that snow does not linger on high slopes. However, it is generally accepted that some snow layer on the roof plays the role of additional thermal insulation.

To eliminate the risk of a break in the roofing material, a strong rafter system is carried out, because a lot of weight will affect the entire structure.

It is worth remembering that the greater the slope of the roof, the more funds will have to be spent on construction. Also, costs are associated with the choice of roofing option (not all materials can be laid on high pitched roofs).

For different materials

Before choosing a roofing material, you should carefully consider technical features coatings. This will help you accept optimal solution and choose the most reliable option. There are rules that determine the relationship between the angle of inclination of the roof and the applied roof structure.

Slate or shingles can be laid on a roof with a minimum slope of 22 degrees. On roofs with a smaller slope, moisture will accumulate and seep inside at the joints of the parts. If the roof has slopes with a smaller degree, roofing material and other bituminous materials can be used, which are mounted in one piece.

Profiled sheet manufacturers claim that this material can be laid at a minimum allowable angle of 12 degrees. Moreover, if the slope angle is minimal, then the joints between the sheets must be glued with a sealant.

For metal tiles, the minimum possible slope of the slope is 14 degrees. At the same time, there are rules for arranging floors. For example, if the angle is more than 45 degrees, then the mounting location of the ridge board changes. The method of mounting the skate itself also changes. For small values, an aero roller is attached between the ridge bar and the tile. It does not allow snow to penetrate under the roof.

For a roof covered with ondulin, the minimum possible slope is 6 degrees. For soft tiles, the optimal surface slope is 11 degrees. Although for this material a larger slope is acceptable. In this case, the crate must be necessarily continuous.

Membrane-type coatings are more versatile. pvc membrane, EPDM membrane, TPO membrane is modern materials suitable for roofs of any shape. The versatility of materials is due to excellent technical specifications and long service life.

When choosing one or another coating material, one should take into account not only the features of the slopes, but also the strength values of the roof. Structures must support not only their own weight, but also the mass of the roofing material. In addition, the entire roofing system must successfully withstand external loads.

The slope of the slopes is often associated not only with the choice of materials, but also with the choice of the type of crate. If the slope angle is small, then a solid crate is mounted. Also, when installing a flat roof, a drainage system is required. For any type of roofing, there are regulatory parameters. They should be kept in mind even if the simplest flat option is chosen.

Standard values

Arranging a flat roof is a simple undertaking. The main thing is to use the right high quality material. Equally important is the slope of a flat roof.

In fact, a flat roof is not completely horizontal. On such a roof, a slope equal to 15 degrees is constructed. Slopes must be present, since only in this case the water will drain into the drains. If the slope is not done in accordance with established standards, stagnant water will form on the roof surface.

When choosing one or another basis, the type of construction should be taken into account. For example, if the floors are wooden, then additional weight for the roof is contraindicated.

To date, on sale you can find special plates that are distinguished by high thermal insulation qualities. Such plates are wedge-shaped. It is enough to lay the material on a flat surface. You will get a slope that meets the standard indicators. The only drawback of the material is the rather high cost.

When using other materials, first you need to make sure that the surface is absolutely flat. Then beacons are installed on it. The slope should be directed to the drains.

When creating a slope, it is worth considering the area of \u200b\u200bthe roof. For the roof of a garage, for example, it is worth considering one slope, which will be directed into the drain funnel. Razuklonka for a standard house measuring 80 square meters. m will be 2-4 slope. At the same time, all of them must be sent to the drainage system in order to freely deliver water to it.

How to calculate?

If there are usually no difficulties with arranging a flat roof, then engineering calculations are necessary to install a roof with several slopes. The easiest way to calculate and determine the values \u200b\u200bis in degrees. For example, for arranging a roof with a sloping angle of 30 degrees, you can use the mathematical method.

This will require two measurements.

Vertical height (H). The value is measured from the top of the inclined plane to the bottom of the rafter system (from the ridge to the eaves).
Pawn (L). This is the horizontal length from the middle of the bottom of the slope to the eaves.

Mathematical calculation is made according to the formula. You can calculate the desired parameter like this: I \u003d H: L. For example, the laying length is 5 m, and the height is 3 m. In this case, the slope will be equal to 0.6 (when calculating I = 3: 5). This value must be multiplied by 100. It turns out 60 percent.

To convert the value to degrees, you can use a special ratio table. It can be found in specialized textbooks. Sometimes such a table can be found on sale in construction hypermarkets. It is not necessary to convert relative values. With the values from the above example, the angle of inclination will be 30 degrees.

Specialists in their measurements do not always use a conversion table. The coefficient in percent can be used in the same way as the coefficient in degrees. In general, professionals use special tools in calculations. For example, you can measure the area parameter using a special inclinometer.

The tool is a ruler with a rail. One axis contains the usual scale in centimeters, the other - the pendulum. If the scale bar is horizontal, then the pendulum will indicate zero. When measuring the slope, the rail is set perpendicular to the ridge. In this case, the scale shows the result for a specific value immediately in degrees.

Currently on the market you can find a variety of tools that can measure slopes. Levels can be both drip-type devices and electronic devices. In this regard, the mathematical method of measurement cannot be considered relevant. Modern appliances allow for more accurate calculations.

The content of the article

Several factors influence the minimum roof slope, not the least of which is the climate of a particular region. The roof, in addition to protecting the interior of the house from exposure external environment, experiences loads from them. Snow cover, summer rains, wind - all these factors have an impact on the choice of both the shape of the roof and its slope.

What affects the slope of the roof slope?

In areas where strong wind loads prevail, it is customary to make a slight slope of the roof. In such areas, a high roof creates additional windage, which can lead to its failure. In order to minimize these risks, it is necessary to make a reinforced truss system, which leads to a significant increase in the cost of the entire construction.
In areas with heavy snow loads, roofs are erected with a slope of up to 45 degrees or more. On such a roof, snow will not linger, therefore, the rafter system does not need to be made reinforced. For roofs with such a slope, the load from the snow cover is no longer taken into account.

Low-slope roofing is carried out in regions with low rainfall and abundance sunny days. In this case, the roofs are built more flat. For roofs with a minimum slope, it is recommended to use membrane roofing materials that reliably protect the roof from leaks.

The abundance of the sun gives a strong heating of the roofing material, which, as a rule, for flat roofs is selected from rolled or piece materials on a bitumen basis. Often, in order to protect the roof from overheating, pebbles are sprinkled on their surfaces, sod or green coatings are made.

But even in this case, the minimum slope of a flat roof must be supported by a drainage system so that even a meager amount of precipitation does not linger on the surface of the roofing.

The drainage system on flat roofs can be both external and internal. Internal drain suit in areas with severe winters. In this case, the drainage system will not be exposed to the destructive effect of low negative temperatures. In any case, the slope of the roof is made towards the water intake funnels in such a way that water can drain into them by gravity.

Slope angle and roofing material

The choice of roofing material also affects the angle of the slope of the roof slopes. Materials with a smooth surface will help drain water from the roof more quickly. Conversely, materials with a rough surface will prevent the rapid outflow of water.

Roof slope angle , in turn, dictates the conditions for the selection of the truss system and all components of the roof - rafters, sheathing step, roofing material. Naturally, the steeper the roof slope, the better and faster the outflow of water. In addition, a high roof looks better and there is more choice of roofing for it.

As for roofing materials, each of them has its own recommended roof slope.

minimum roof pitch and cover

The minimum slope of the roof from corrugated board make it equal to 12 degrees, for a roof covered with metal tiles, the slope increases to 15 degrees. But with such a small angle of the roof slope, all joints between individual sheets or other elements must be treated with a water and frost-resistant sealant. In addition, if the roof slope angle is 15 degrees or more, the profiled sheet is laid with an overlap of 200 mm, with a smaller slope angle, the overlap increases by two waves. The step of the crate under the profiled sheet also depends on the angle of the roof slope. The greater the slope, the wider the crate step becomes. With a minimum slope angle, the crate can be continuous.

Roll or piece roofing materials based on bitumen, as well as membrane coatings, ondulin, can be laid on the roof with a minimum slope of only two degrees or more. When choosing rolled materials, the number of layers of soft roofing affects the angle of inclination. The more layers, the lower the angle of the roof slope, as its waterproofing ability increases. If a soft roof is made from 1 or two layers of rolled material, then the angle of the roof slope can reach up to 15 degrees.

Soft tiles(ondulin) can be laid on a roof with a slope angle of 11 degrees, but the crate in this case must be continuous.

Minimum slope of a pitched roof covered with asbestos cement sheets or ceramic tiles the slope of the roof slope must be at least 22 degrees. You should also not forget that the smaller the angle of slope of a pitched roof covered with slate or natural tiles, the greater the load is created on the truss system along the entire plane of the slope. Therefore, the truss system must be calculated taking into account the slope of the roof.

How and with what is the angle of the roof slope measured?

The slope angle of any roof can be calculated using geometric functions or a device called an inclinometer. The angle of the roof slope can be measured in degrees, percentages or their ratios.

The mathematical approach to the calculation is to first find out the length of the legs or hypotenuse. The hypotenuse will be a straight line represented by the roof slope. The opposite leg will be the distance from the ceiling to the ridge, the length of the adjacent leg is the distance from the middle of the ceiling to the cornice overhang of one of the roof slopes.

Knowing two of the three values using trigonometric functions, you can easily calculate the minimum slope of a soft roof. The resulting value of the sine, cosine or tangent, depending on the dimensions of which components of the right triangle were used, is used to find the percentage value of the roof slope angle using an engineering calculator.

Another way to determine the angle of the roof slope is to determine the ratio between the height from the ceiling to the ridge and half the width of the ceiling. The height is divided by ½ the width of the building and multiplied by 100. Further determination takes place according to a special table.

Roofs made with a minimum slope must be equipped with the correct drainage system. The slope of the roof is made towards the water intake funnels, if provided internal system catchment, and towards the gutters, if an external catchment is arranged.