What should be the minimum slope of a corrugated roof? Roof slope made of corrugated sheets - how to choose the right one? Roof under corrugated sheet with low slope
It is important to understand that if the house has a pitched roof, then one wall will be significantly higher than the other.
This leads to increased consumption of building materials.
Before you begin calculating the slope of the roof, you need to understand the degree of impact on. There are two types of loads - dynamic and constant.
To permanent loads include those which will affect roofing Always, regardless of the time of year. This includes the chimney, antenna, the weight of the roof itself, etc.
Regarding dynamic loads, then these are non-constant quantities, i.e. weight that affects the roof from time to time. Such an impact can be caused by the weight of a person who periodically visits the roof to carry out any work, the weight of snow and hail, the impact of wind, etc.
If the roof slope is 30 0, then the force of snow will be 50 kilograms per square meter. If you increase the angle pitched roof up to 45 0, then most likely the snow will not linger on the roof.
That's why this value should be selected based on your region of residence, i.e. based on the amount of precipitation.
At the same time, if you want the snow to melt off the roofing on its own (at least some part of it), then the minimum slope value should be 10 0. The maximum value is 60 0.
Be that as it may, owners of houses with pitched roofs carry out self-removal of snow from the roof to reduce the load on the roof.
Wind loads
The design of a pitched roof is such that it is always made with a low part towards the leeward side in order to reduce the load from the wind.
Combined loads
Many people ignore this fact, which often leads to unpleasant situations. This type of load represents the maximum impact, which ends up on the roofing at some point.
It is necessary to provide for the critical load, consisting of permanent and dynamic influences, that the roof can withstand.
Let's imagine a situation when there is a snow storm outside, i.e. the roof is exposed to both strong wind and snow mass at the same time. In addition, a person is forced to climb onto the roof to adjust the antenna or he has to pick up a toolbox, it doesn’t matter.
It turns out that in addition to snow and wind, the weight of the human body is added. If you do not take this fact into account, the roof may not withstand.
Dependence of slope on the choice of roofing material
In addition to various atmospheric phenomena, the slope will be influenced by the roof covering that a person uses in this particular case.
Here are the minimum values for various materials:
- , or any other piece material can be used on the roof, the minimum slope value of which is 22 0.
- If you apply rolled materials , then the number of layers matters. A two-layer coating will require at least 15 0, and if the material is spread in three layers, then from 2 to 5 0 will be enough.
- If used, the minimum tilt angle should be 12 0. If this value is smaller, then you will need extra work in the form of gluing joints for better sealing.
- The angle at is 14 0.
- The angle at equals 6 0.
- will require at least 11 0 tilt.
ATTENTION!
If you intend to install a pitched roof, then not every roofing material you like may be suitable for you.
This means that if the slope of your roof is less than the minimum parameter characteristic of a particular material, then you should refuse to use it.
Angle of inclination depending on roofing covering
How to measure the pitch of a pitched roof
We have already said that with pitched roofs the height of the walls will be different. That is why the slope of a pitched roof will be formed at the time of construction of the walls themselves, on which the roof will be subsequently installed.
If in your region there is large number snow, then the values should be 45-60 0. If you are in a temperate zone, then the parameters will be as follows - 5-60 0. Of course, the minimum angle of inclination must also be taken into account, depending on the material used.
Lwalls = Llength * tgQ,
Where Lwalls — this is the height of the pediment;
Llength — this is the length of the wall;
Q - this is the angle of inclination.
It is also necessary to take into account the lengths of the rafters. It is calculated using the following formula:
Lrafters = Lwalls / sinQ.
The values of sine and cotangent should be taken from this table:
Here is an approximate calculation. Let's say we use ordinary tiles, so the minimum angle of inclination is 22 0. To calculate, we take 25 0 - the value of Q.
The length of the wall is 7 meters, i.e. Llength = 7m.
Lwalls = 7 meters * tg25 = 7 * 0.47 = 3.29 meters.
Lrafters = 3.29 / sin25 = 3.29 / 0.42 = 7.83 meters.
Minimum slope angle of a pitched roof
To calculate the minimum slope of a pitched roof directly affects the level of precipitation, which may be different for each region.
If you live in a "snowy" area, then the pitched roof should be quite steep, i.e. within 45 0.
In this case, the snow will not linger on the roof, which will significantly reduce the load on the roof.
If your area doesn't get a lot of snow, then 25 0 is enough.
The situation is opposite in those regions where there are strong winds . Here you need to build roofs with a slight slope so that the load from the wind is minimal.
Also big role when choosing the minimum angle of inclination, the type of roofing material, which we talked about a little earlier, plays a role. You can read more about the minimum angle and its calculation.
Minimum angle
The optimal angle of inclination of a pitched roof made of corrugated sheets
Corrugated sheeting is a rather “harmful” material, because it has many layers with different sizes waves, as well as the thickness of the material itself.
According to SNiP, the minimum slope for residential premises whose roofs are covered with corrugated sheets is 12 degrees. According to the same rules, optimal parameter this inclination should be 20 degrees.
For a long time, pitched roofs were considered the domain of garages or various non-residential premises, but in lately the situation is changing. Many people note the fact that when choosing this type of roof, interior design the room becomes more original, although more troublesome in terms of decoration.
But this does not stop those who value not only reliability in their home, but also attractive appearance.
Optimal angle
The large size of the corrugated sheeting, which allows one sheet to cover the area from the ridge to the eaves, makes it tempting to make the roof almost horizontally - this is the easiest way to install structures. It is better to abandon such an idea solely because the minimum slope of a roof made of corrugated sheets can result in damage to the roof in winter from snow loads, and in summer the penetration of water into the under-roof space under the influence of strong winds. On the other hand, the steeper the roof slope, the less snow will linger on it, and water has no chance at all of wetting the ceiling in the house. But such a roof is more difficult to build. How to find the golden mean, what angle of inclination to choose so that it is easier to build and the under-roof space is guaranteed to remain dry?
Angles in general, including the angle of inclination of the roof, are usually measured in degrees. But in SNiP it is customary to measure slopes as percentages, which are determined by the ratio of the height of the roof from the floor to the ridge to the distance from the projection of the ridge on the floor to the eaves, multiplied by 100. For example, 1: 9.5 x 100 = 10.5%. Therefore, to make it clear what angles we are talking about, we present a table of correspondences.
| Degrees | % | Degrees | % | Degrees | % |
|---|---|---|---|---|---|
| 1 | 1,7 | 16 | 28,7 | 31 | 60,0 |
| 2 | 3,5 | 17 | 30,5 | 32 | 62,4 |
| 3 | 5,2 | 18 | 32,5 | 33 | 64,9 |
| 4 | 7 | 19 | 34,4 | 34 | 67,4 |
| 5 | 8,7 | 20 | 36,4 | 35 | 70,0 |
| 6 | 10,5 | 21 | 38,4 | 36 | 72,6 |
| 7 | 12,3 | 22 | 40,4 | 37 | 75,4 |
| 8 | 14,1 | 23 | 42,4 | 38 | 78,9 |
| 9 | 15,8 | 24 | 44,5 | 39 | 80,9 |
| 10 | 17,6 | 25 | 46,6 | 40 | 83,9 |
| 11 | 19,3 | 26 | 48,7 | 41 | 86,0 |
| 12 | 21,1 | 27 | 50,9 | 42 | 90,0 |
| 13 | 23 | 28 | 53,1 | 43 | 93,0 |
| 14 | 24,9 | 29 | 55,4 | 44 | 96,5 |
| 15 | 26,8 | 30 | 57,7 | 45 | 100,0 |
When the roof slope is from 6° to 12°, it is necessary to seal the longitudinal and transverse joints between the sheets. For slopes greater than 12°, sealing joints is not necessary. It is enough to adhere to the recommended parameters for overlapping sheets in the longitudinal and transverse directions. But all this general requirements building codes and regulations. What else influences the choice of roof slope from corrugated sheets?
Here are the main points that determine not only the slope, but also much more:- Financial opportunities come first.
- The building plan determines the very shape of the roof.
- The presence or absence of an attic.
The desire to have an attic also results in significant costs both for its arrangement and for the design of the entire system of rafters and sheathing. Snow and wind loads, unfortunately, do not depend on the financial capabilities of the construction customer. Quite the contrary - they dictate their terms and force them to bear certain costs to ensure the strength and safety of the roof in general and the roof in particular.
It is always desirable to slope the roof so that the snow does not linger on it, but rolls down almost immediately when it snows. Unfortunately, this is not always possible and not in all regions. In some conditions, spontaneous snow melting is generally not desirable for safety reasons. In such cases, snow-retaining structures are installed on the roof, and the snow is thrown down, subject to the necessary organizational and technical specifications. The design of the rafters and the rigidity of the corrugated board are of particular importance here. 
IN recent years Hurricane winds occur even in places where previously they were only heard about on the radio and seen on TV. Therefore, it is especially necessary to pay attention to wind loads during new construction and when repairing old roofs. It is not always possible to reduce the windage of a roof, so a slope that allows you to reduce the lifting force will partially help solve the safety problem. It is also necessary to take measures to eliminate the possibility of gusts of wind blowing under the sheets and subsequently tearing them off. All necessary constructive solutions for this there is. You just need to strictly follow them when carrying out construction and installation work. With the help of snow and wind load maps, you can decide on the choice of the profile height of the corrugated sheet and the angle of the roof. The profile height directly affects the rigidity of the profiled sheet, and therefore its bearing capacity. A more rigid corrugated sheet can withstand a greater snow load, which means the roof can be made flatter. On the other hand, the smaller the angle of inclination of the roof, the greater the chance that in strong winds it may not be protected from moisture penetration into the roofing “pie” through the joints of the corrugated sheeting. And a flatter roof requires stronger support in the form of a complicated rafter structure. 
The presence or absence of an attic in the construction plans also has an impact on these aspects of the roof structure, since the area and height of the ceiling in the attic directly depends on the magnitude of the slope. The greater the angle of inclination of the roof slope, the greater the useful volume of the attic. 
There is also a relationship between the slope angle, the section of the flooring profile and the roof sheathing. If the angle of inclination of the roof is less than 10°, it is recommended to make the sheathing continuous, the transverse overlap of the corrugated sheets should be at least 300 mm, and in the longitudinal direction it is better to lay two waves of the next sheet on top of the previous sheet. With a slope of 10° to 15° in the longitudinal direction, you can limit yourself to one wave, and for a transverse overlap, 200 mm is enough. The sheathing pitch can reach 450 mm. When the angle of inclination exceeds 15°, the sheathing pitch can be increased and the overlap reduced. 
Of course, the pitch of the sheathing also depends on the height of the profile. The more rigid the profiled sheet is, the larger the pitch can be. The latter can also be changed depending on the cross-section of the board or timber used. Sheathing sections depending on the roof slope and rafter pitch, mm |
||||||
| Lathing pitch, mm | Roof slope |
|||||
1:3 and flatter |
||||||
| Rafter pitch 0.9 m | Rafter spacing 1.2 m | Rafter pitch 0.9 m | Rafter spacing 1.2 m | Rafter pitch 0.9 m | Rafter spacing 1.2 m | |
| 250 | 22x100 | 25x100 | 22x100 | 25x100 | 22x100 | 32x100 |
| 300 | 22x100 | 25x100 | 22x100 | 32x100 | 25x100 | 32x100 |
| 400 | 22x100 | 32x100 | 22x100 | 32x100 | 25x100 | 38x100 |
| 450 | 22x100 | 32x100 | 25x100 | 32x100 | 32x100 | 38x100 |
| 600 | 25x100 | 32x100 | 25x100 | 32x100 | 32x100 | 38x100 |
| 750 | 32x100 | 38x100 | 32x100 | 38x100 | 32x100 | 50x100 |
| 900 | 32x100 | 38x100 | 32x100 | 38x100 | 38x100 | 50x100 |
| 1200 | 32x100 | 50x100 | 32x100 | 50x100 | 38x100 | 50x100 |
| 1500 | 50x100 | 50x100 | 50x100 | 50x100 | 50x100 | 50x100 |
Selecting a slope option
Ultimately, the right to determine the slope of a corrugated sheet roof remains with the customer. After all, it is obvious that such a number of factors influencing the strength characteristics of the roof imposes certain restrictions. But at the same time, they presuppose freedom of choice. For example, with all the “aggravating” loads on the roof, you can use a corrugated sheet with greater rigidity than what is expected in the calculations, or reduce the pitch of the rafters and increase the cross-section of the timber for the sheathing. This will reduce the angle of the roof. When performing installation, in any case, it is necessary to follow all the recommendations of building codes and regulations, as well as practitioners, and then even the most minimal slope of a corrugated roofing will not cause problems during operation and will not become a reason for disappointment.If the rafter system were strong and the corrugated sheeting was of high quality, then the angle of inclination would not be so important! This is what many owners of private houses think when planning to build a roof. And if you are also one of them, we advise you to carefully read the information presented below. Today you will find out what the minimum slope of a corrugated sheet roof is, and why it is so important to strictly adhere to these standards.
What kind of roofs do craftsmen distinguish by type of slope?
1. Flat roofs– when the slope is inclined at an angle of no more than 5 degrees. We can see this option on multi-storey buildings and large commercial buildings.
2. With minimal slope– from 5 to 12 degrees. Such roofs are found in southern regions where there is almost no precipitation, and in windy areas.
3. Pitched roofs – with an angle from 15 to 25 degrees. Such roofs are less sensitive to precipitation accumulation. This option is most popular in the central regions of Russia.
4. Steep roofs– angle 40 degrees or more. Steep slope is popular in construction country houses, where attic spaces are very often installed. This angle requires strengthening the rafter system, taking into account wind loads.
And right away, a small three-part master class on building a roof with a minimum angle of inclination:
Why do builders propose to make a minimum roof slope?
A professional craftsman will never advise you on the minimum roof slope unless there is a good reason for it. These include the following:
- Construction is taking place in areas with the strongest wind loads;
- You use the most reliable brand of corrugated sheeting that can withstand heavy loads (snowfall), or there is almost no snow in your region;
- You are constructing a temporary roof for a house or outbuildings;
- Or everything is much simpler - you insist on a minimum slope, because you hope to save on the consumption of roofing material.
By the way, very often experts in determining the roof angle talk not only about degrees, but also percentages, and even coefficients. How to understand them? Let's look at the illustration:
Is it really possible to save a lot of money on corrugated sheets on a flat roof?
Some savings, of course, are present with a low roof slope. However, gentle slopes require more overlap of materials, more expensive sealing of joints, and better quality waterproofing membrane, and strengthening the rafter system (if there are strong winds in the region). Thus, the savings are minimal, and the risks do not disappear.
How to calculate the roof slope angle yourself?
To do this, let's look at the illustration:
Roof slope and factors influencing it
There are several major factors that determine the choice of roof slope, and many minor ones. Let's look at the main ones:
- Type of building and its purpose;
- Weather conditions terrain;
- Characteristics of the roofing material;
- Additional measures to strengthen and insulate the roof.
I. Type of building and its purpose
What is the minimum roof slope for corrugated sheets? This question is answered by SNiP standards, which set out recommended indicators for the regions of our country.
Thus, according to official data, the minimum slope slope for roofing with corrugated sheets for outbuildings is 8 degrees, for residential buildings - 10 degrees. This angle allows water to not pass through at the joints of sheets and at fastening points, and can withstand a small layer of snow (15-20 cm).
This is data on the minimum permissible slope, but there is also such a thing as a recommended minimum slope. In this case, experts call the minimum figure - 12 degrees, and the optimal - 20 degrees. Note that many construction companies insist on precisely this minimum angle, and otherwise, they do not give any guarantees for work. Why is this so? It is these figures that allow the load to be evenly distributed across roofing system and load-bearing partitions of the house, do not additionally seal seams and fastenings, do not double overlap materials and ensure safe convergence of precipitation.
Another important point when choosing the degree of slope - the presence of an attic. If you are planning attic room, then you need to choose a roof slope of at least 40 degrees.
II. Weather conditions of the area
1. Wind. More from school course Physics and geography, we can conclude that a strong wind tries to overturn a high roof, and lift a flat roof. That is why experts advise choosing a minimum roof slope for windy regions and reliable fastening roof frame to base:
2. Rain. Rain is not only excess moisture, which penetrates under a flat roof faster than under steep slopes. This is also the mechanical force with which the drops hit the roof. The higher the slope angle, the less impact force rain or hail. Note that in some cases these weather phenomena may well deform or pierce the material. Therefore, if you live in a region where such weather is not uncommon, then you should think about the maximum possible roof slope. By the way, the maximum for corrugated sheeting is also quite sharp - up to 70 and even 75 degrees.
3. Snow. Snow is a uniform load that lingers on a low roof and can reach up to 500 kg per 1 m2 (in some regions of Russia). With such a load, a roof with a slope of 8-20 degrees can simply collapse on the owners’ heads. To do this, in snowy regions, experts recommend increasing roof slope up to 40-45 degrees:
Of course, there are areas where all weather disasters can occur frequently and even simultaneously. In this case, trusted specialists in your locality, or neighbors who know exactly how their roofs react to the local vagaries of nature, will help you calculate the angle of the roof. Data on wind and sediment loads on planes in your area, which can be found on the corresponding maps, will help with the calculations.
III. Characteristics of roofing material
Corrugated sheets are galvanized steel profiled sheets with a polymer coating. The latter makes the material resistant to corrosion and allows it not to retain precipitation during correct tilt stingray:
IV. Additional measures to strengthen and insulate the roof
If you are determined to make a minimal roof slope from corrugated sheets, then you should think about additional measures to strengthen the rafter system and laying high-quality waterproofing on the slopes from the inside, and on the joints from the outside.
With a minimum slope of a roof with corrugated sheets, you must:
- Select the size of the rafters to be at least 100x200 mm and install them in increments of at least 60 cm;
- Strengthen the fastening of the Mauerlat to the load-bearing external partitions. The Mauerlat should be reinforced with threaded spiers;
- Strengthen the fastening rafter legs using wire, anchors and metal corners;
- Place a high-quality waterproofing membrane under the insulation;
- Install the counter-lattice and sheathing at intervals of at least 40 cm. If the slope is less than 12 degrees, then it is better to make a continuous sheathing from high-quality moisture-resistant plywood;
- Overlap the corrugated sheets onto each other by at least 20 cm (it’s best to have 2 sheet waves);
- Carefully seal all seams and fastening points with construction sealant.
An example of installing a profiled sheet with a minimum slope
So, let's summarize. A small roof slope is good for outbuildings, garages, houses located in regions with strong wind loads and sunny southern areas. However, nothing is impossible! If you take all the necessary measures, take into account the conditions and important factors, given above, you can build an excellent low-pitched roof for your home. We wish you success!
The roof of any building is important element. To install the structure, high-quality and high-strength building materials are selected. The most popular material used by consumers can be called corrugated sheeting. The angle of the roof must be chosen taking into account the appearance of the building, SNIP, design and much more. The choice of roof slope is influenced by many factors.
Factors influencing the choice of slope
It is necessary to note three main reasons that have a significant impact on the choice of the angle of inclination of the structure in percentage:
- wind strength and direction;
- amount of rain;
- snow depth.
A small slope angle has its advantages and disadvantages. The advantage of a slight slope is its resistance to strong gusts of wind. The downside is the additional careful sealing of all joints of the coating to avoid leakage during heavy heavy rains (water drains from such roofs much more slowly). In some regions, the winter is too long and a large layer of snow accumulates on the roofs. From roofs whose slope angle is insignificant, the snow layer moves off much more slowly.
When the roof structure is not strong enough, it causes the roof to collapse. You have to remove the snow yourself. To avoid such unpleasant situations, all structural elements should be strengthened. Need to install additional elements to strengthen the rafters. The snow layer must be cleared from the roof in a timely manner.
The choice of corrugated sheets for covering a pitched roof should be approached carefully: the durability of the structure depends on this. The configuration of the profiled sheets plays an important role in this case. The most rigid are products with a high wave. Profiled sheets universal use and wall products have a less rigid structure. It is equally important to take into account financial capabilities when purchasing the necessary material.
Characteristics
An important role when choosing the roof slope angle is played by the technical characteristics of the corrugated sheet. For making of this material They use special steel, the sheet thickness of which should be about 0.7 mm. The steel sheet is treated with a special composition containing zinc, as well as a polymer or paint substance. Next, the processed sheet is processed on a special machine. After this, it takes on a wave-like shape. The waves can be in the shape of a trapezoid or a rectangle. This is necessary to increase the strength and reliability of the material. There are three types of corrugated sheets. It can be roofing, wall or mixed.
Distinctive Features of this material consist in thickness the steel used for its production, low profile height, affordable cost. This type of building material is the best option for finishing wall surfaces, making fences and roofs small sizes. For making load-bearing type material used steel sheets, having a greater thickness than wall option corrugated sheets The peculiarity of this building material is the additional stiffening ribs.
Thanks to additional ribs, the covering made of load-bearing corrugated sheets can withstand much greater loads. The scope of application of such building materials is quite wide. It is used in the construction of garages, hangars and other buildings, as well as for covering roofs large size. Due to excellent technical characteristics a universal type of corrugated sheet can be used in construction for any purpose.
Corner
There are special building codes, which clearly outline the optimal standards for installing and creating various coatings buildings. To cover a roof made of corrugated sheets, the minimum angle of inclination of the structure is about 8 degrees, based on building regulations. In this case, continuous or frequent sheathing should be installed. According to construction professionals, a flatter structure can be installed, but subject to certain nuances. With a smaller slope of the roof angle, it is enough just to increase the overlap between the sheets of corrugated sheets. Be sure to treat all joints with a special silicone sealant. This will help avoid leakage.
Types
There are three types of roofs made of corrugated sheets.
Low slope
With this type of roof slope, material consumption increases significantly. This leads to additional financial costs. The consumption is due to the large overlap of one sheet on another (horizontally and vertically) of about 20 cm. In addition, it is necessary to additionally protect the rafters from moisture. For this purpose, it is advisable to use a special membrane material. This measure is necessary to ensure waterproofing of the coating. The angle of inclination of a low-slope structure is usually less than 14 degrees.
Medium slope
It's more economical option installation of the structure. The angle of inclination of a medium-slope roof ranges from 15 to 30 degrees. In this case, the overlap of one sheet of corrugated sheet onto another is much less. This allows you to significantly save on building materials. Consequently, financial costs are reduced.
Steeply inclined
The slope of this roof structure is more than 30 degrees. Installation of corrugated sheets is carried out with minimal overlap. This type of installation of a building roof structure is the most economical and less expensive.
Dependence on roof slope
During the construction process, industrial buildings are most often installed flat roofs. Roofs with one slope are installed on outbuildings. Residential buildings, as a rule, have gable, hip and hip roofs. The corrugated sheet covering is installed on a strong, reliable base that can withstand the significant weight of the structure. With the help of the base, the weight of the corrugated sheet is evenly distributed over the entire surface of the roof. The type of sheathing should be selected depending on the roof slope.
During the installation of low-slope structures coated with corrugated sheets, the profile height of which is about 20 mm, sheathing should be used for the construction of edged board about 3 cm thick. In order for the support of the structure to be stronger and more reliable, a solid base should be installed. To install low-slope roofs covered with corrugated sheets with a profile height greater than 35 mm, it is permissible to construct a base in the form of a lattice. The distance between the boards in such a sheathing should not exceed 30 cm. When installing a medium-slope roof covered with corrugated sheets, the profile height of which is about 44 mm, the best option for installing the base would be to use a board about 3 cm thick. The permissible distance between the boards should be no more 50 cm.
Advantages
Before choosing a roof slope, you need to know the benefits of a minimum slope. The advantage of building a roof with a minimal slope is the low consumption of material.
- Installing such a roof is much easier and safer.
- There is no ridge in the design of this roof model. Thanks to this, there is no need to seal it.
- The load on the foundation and building structure is much less than that of roof models with a large slope.
The greater the roof slope, the greater the load on the foundation and structure of the building. At the same time, material consumption increases.
Flaws
Disadvantages this option There are quite a lot of roofs. During heavy, heavy rain, moisture drains from such a roof more slowly than from steeper roofs. Water will penetrate into joints and cracks. Therefore, the construction of a roof with a slight slope requires careful sealing (especially joints and overlapping areas of corrugated sheets).
To cover this type of roof, the best option would be to use only load-bearing corrugated sheeting, which is more durable and has a high profile. The covering of a steep roof can be made from any corrugated sheet. Universal, wall and load-bearing profiled sheets are suitable. Precipitation will not linger on such coatings.
When installing a roof with a slight slope, the angle of which is less than 12 degrees, the consumption of building materials increases significantly. In this case, it is necessary to increase the overlap of one sheet onto another; additional sealing of joints and overlaps will be required. However, if the roof slope is from 12 to 15 degrees, it is quite possible to do without sealant. That's why optimal angle For the slope of a roof made of corrugated sheets, an angle of 12 to 30 degrees is considered.
Despite the fact that installing a steep roof will require a fairly large number of boards, significant savings will be obtained on the purchase of corrugated sheeting. You can purchase less expensive versions of corrugated sheets with a low profile height. With a minimum roof slope angle, installing a residential attic is absolutely impossible. Installing a roof with a minimum slope angle involves installing more complex design rafter system. The design must be more durable and reliable to withstand significant loads and heavy weight. You will have to reduce the pitch between the rafters and choose a more durable material. This will affect the weight load on the carriers.
Wind and snow loads
When choosing and calculating the angle of inclination of a roof made of corrugated sheets, it is important to take into account many various nuances. The climatic conditions of the area where the construction of the building is planned plays an important role in this. It is necessary to first study the features of the local climate, the approximate amount of precipitation throughout the year, the strength and direction of the wind, and the approximate height of the snow cover. Roofing material must withstand weather conditions.
For regions where strong winds prevail, the best option is to install a roof with a minimum slope. This will prevent the structure from collapsing during strong gusts of wind. However, it should be noted that flat roofs they may also get hurt in the process. Therefore, it is necessary to correctly calculate the optimal minimum roof slope angle for a given area.
In addition to the wind load, the calculation of the roof inclination angle of a building has a significant influence snow load. It is no secret that in many territories in winter period A significant amount of snow falls, forming a heavy snow cover. Even the strongest rafter system design cannot always withstand such loads. Therefore, the best option in such areas is to install steep roofs. You can install a roof with a minimum slope, but in this case you will have to promptly clear the roof of snow cover in order to avoid destruction of the roof.
Installation nuances
Roof installation with minimal inclination most popular in regions with warm climatic conditions and little precipitation. The roof structure is installed taking into account the climate and is additionally equipped with thermal insulation and ventilation. This is necessary to reduce the heating of the room and rid it of condensation. These operations are carried out in accordance with generally accepted instructions, using high-quality raw materials.
In order for the roof to reliably protect the house and last as long as possible, during its construction it is necessary to take into account at what angle it will be built in relation to the house itself. Great influence At the same time, climate, wind rose, and abundance of precipitation in the populated area where the house is being built have an impact. But the material that will serve as the roof is also important.
First of all, it should be noted that roofing with corrugated sheets is ideal if the length of its slope is less than 12 meters. When laying corrugated sheets on the roof, it is important to comply with all the requirements of SNiP, which recommend the use of wall, universal corrugated sheets, as well as profiled sheets for floors and with a wave height above 20 mm. When choosing a profiled sheet, you must ensure its compliance polymer coating climate features.
It has already been taken as a rule to measure the angle of the roof in degrees or percentages:
One degree is equal to 1.7 percent, and 45 degrees is equal to 100 percent.
The higher the angle of the roof, the less snow will put pressure on it in winter, and the faster water will drain away in summer. However, the influence of the wind rose (in other words, the windage of the roof) increases significantly. If the roof slope is insignificant, then the influence of the wind will decrease, but the load on the roof from precipitation will correspondingly increase, which means you will have to think about ensuring reliable sealing and water resistance of the roofing material.
Depending on climatic conditions, in which the house is built, the angle of inclination is taken into account. Where there is a lot of rainfall, it is best to make the roof at an angle of 45 degrees so that raindrops or snow do not linger on the roof. If the area is dominated by dry and warm days, then the angle of inclination should be minimal (in the case of corrugated sheeting, 8 - 10 degrees). The same roof slope would be appropriate in areas where storm winds are possible.
For materials such as corrugated sheets, SNiP recommend a slope of 20 degrees (36.4 percent). This is an ideal slope for a profiled sheet. But the roofs on houses are made differently and their angle of inclination is not always 20 degrees. Therefore, there is a minimum permitted roof slope angle for each material selected for the roof, including profile sheets.
The minimum degree of slope angle of a corrugated roof for industrial or commercial buildings is 8 degrees (14.1 degrees), for residential buildings - 10 degrees (17.6 percent). If the roof is laid in several layers (for example, two), then these numbers will increase, that is, the roof slope angle must be increased to prevent moisture from accumulating at the joints of the corrugated sheeting.
The smaller the slope angle, the wider the sheets will have to overlap, which will reduce the effective area of the material. So, for example, with a tilt of 35 degrees. the overlap should be 15 cm, from 15 to 30 g. – 20 cm, less than 15 degrees, two waves of the profile sheet overlap, and its joints (both longitudinal and transverse) can be sealed.
Calculations for calculating the angle of inclination
To make calculations to calculate the angle at which the roof will be inclined, an inclinometer is often used - a device specially designed for this. But it is possible to make calculations yourself, armed with knowledge of trigonometry.
This is where the formula comes in handy right triangle. The legs will represent the gap between the ridge and the ceiling and the gap between the eaves slope and the center of the ceiling. The hypotenuse is the slope of the roof measured in a straight line. Having found out these distances and applied to them trigonometric function, it is possible to easily calculate the most small value roof slope angle.
By dividing the height of the ridge by the length of the slope, we obtain the sine of the angle of the roof slope. Using calculations on a calculator, its value is determined in degrees (percentage). If it is more convenient to use the cosine or tangent functions, then the correspondence of ½ the width of the overlap and the length of the roof slope or the height of the ridge and ½ the width of the overlap is used.
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