Profiled metal flooring can be attributed to an inexpensive, but durable material that is used to cover the roof of industrial, residential and many other outbuildings.
This material is famous for its strength, resistance to corrosion and other mechanical and natural phenomena. If the minimum angle of inclination of the roof from the profile flooring is calculated correctly in advance, then water drainage and snow removal will be effective, and the roofing from it will last about 20–25 years.
Factors affecting the slope of the roof
The main factors by which the magnitude of the slope of the roof from the profile sheet is determined are climatic features the region where the building is located. Namely:
- The level of snow falling in winter.
- The amount of rainfall that falls at one time.
- The power of the wind.
snow pressure
Snow puts the biggest load on the roof of the house. If, for example, rainwater rapidly leaves the roof, then snow, accumulating on the ceiling of the building, can linger on it for quite a long time. Therefore, first of all, when calculating the slope of the roof slope, it is the snow load that is taken into account.
For example, in regions with heavy snowfalls, in order to avoid a large accumulation of snow on roof slopes, they are made with a minimum slope of 20-25 degrees. But in this case, a reinforced truss system with a large number of racks and struts is required, while the roof becomes heavier, the load on the foundation increases.
In order to relieve the weight of the roof structure, the slope is about 45 degrees without additional reinforcement of the rafters.
That is, the steeper the slope of the roof is made, the more difficult it is for the snow mass to stay on the roof slopes. And the snow under its own weight will surely slide off the roof.
wind load
If in the region where the building is being built, there is a danger of demolition of the roofing by strong gusty winds, then the roofs are made more gentle to lower the windage.
According to the developed Building Regulations (SNiP), the angle of the roof slope with an average wind load should be in the range of 35-45 degrees. In strong gusty winds, the slope of the roof is set in the range of 15-25 degrees. That is, in regions with frequent strong winds, in order to minimize the windage of the roof, a slope value close to the minimum is selected. But this cannot be called the optimal solution, since even with the complete absence of a roof slope, it can be blown away by gusts of wind.
The value of the angle of the roof
When choosing the angle of inclination of a shed roof, one should also take into account the characteristics of the profile sheet selected for covering. For example, corrugated board, which has a rather large wave height, can even be used for a roof without any slightest slope. But a wall profiled sheet with shallow waves is suitable for covering roofs with steep slopes.
When using roofing from a profile sheet, it should be remembered that with a minimum slope, water during heavy rain does not always have time to quickly drain from the roof and, naturally, at its joints it can seep under the cover. Therefore, it is recommended, with a minimum slope of the slopes (within 8 degrees), to lay tape sealant under all longitudinal and transverse joints. Sealing can be dispensed with only if the slope angle is at least 12 degrees.
According to SNiP, the angle of inclination of a shed roof made of corrugated board can be even smaller and reach almost 6 degrees, but at the same time, when joining, the sheets must be superimposed on each other within 250–300 mm and carefully treated with silicone sealants.
The main quality of a roof with a minimum slope is such an overlay of sheets so that rainwater is not blown under the joint of the profiled coating by gusts of wind.
But for a load-bearing profile flooring with large waves 114 mm high, an angle of even 6 degrees can only be a convention. It is often used for flat roofs, where it plays the role of the main floor, holding the insulation and waterproofing layer of the soft roof.
Advantages and disadvantages of the minimum slope
Consider advantages of pitched roofs covered with a profiled sheet with a slight slope:
But, in addition to the advantages, the roof with a slight slope has some significant disadvantages:
Characteristics of profiled sheet
For the correct choice of the slope of the roof, covered with a profiled sheet, you need to familiarize yourself with the operational and technical characteristics of this building material.
Profiled flooring is made by stamping or rolling a thin metal sheet with a thickness of 0.5-0.7 mm through special roller rollers, after which it is coated with zinc and various paint and varnish or polymer compositions.
The profile formed on the surface of the sheet increases its strength and ability to withstand large vertical loads in a horizontal position.
Separation of sheets by profile
According to the height of the profile waves, the profiled sheet is divided into three types:
Building material advantage
Profiled steel sheet is different from other roofing materials:
- High strength.
- Long period of operation.
- Small weight.
- Corrosion resistance.
The sheet, according to building codes and regulations, with the right selection of wave heights, can be used to cover buildings with a minimum slope of about 8 degrees. In this case, rainwater practically does not overlap through its waves, which means that it is not necessary to seal the joints between the sheets.
The flooring is well adapted to adverse climatic conditions, which makes it possible to work with it at any time of the year.
Rules for laying profile material
The laying of this profile material to a certain extent depends on the slope of the erected roof, so you need to follow some rules for installing sheets for their further high-quality operation.
For example, the optimal slope of a slope erected above a residential building is considered to be 20 degrees, and the minimum is within 12 degrees. For industrial buildings, the slope can be about 8 degrees.
But these values can change downward and depend on the installation technology of the profiled coating. If, for example, when joining, the overlap of sheets is minimal, then it is mandatory to lay a waterproofing tape between them at the seams or coat them with a special hermetic compound.
In any case, when the roof slope is less than 14 degrees, the overlay of sheets should be within 200 mm, but not less.
On the ridge and valleys, sealing is carried out using seals specially designed for this, made of material that does not allow water to pass through, but allows air to pass freely. In addition, small gaps are left on the ridge for ventilation of the roof.
Of particular note is the laying of sheets on the roof with a slope of less than 12 degrees. Here, in addition to transverse overhead joints, sealing should be carried out along all vertical seams.
According to building codes, the overlay of sheets on horizontal seams should be as follows:
- When the slope of the roof slope is within 12-30 degrees, the overlap can be 150-250 mm.
- When the roof slope is within 30 degrees or more, the lining can be performed in the range of 100-150 mm.
The relationship between the profile and the crate
Buildings intended for industrial use are often covered with shed or flat roofs, and residential buildings can be with two or more slopes.
But any roof covering must be laid on a solid base (batten) that can withstand high loads and evenly distribute them on floor beams in industrial buildings, or on rafters used in residential buildings.
The pitch of the crate depends not only on the slope of the roof, but also on the height of the profile waves of the sheet being mounted. The higher the waves, the greater the load the sheet can withstand.
The lathing is usually selected according to the type of sheet and the slope of the roof slope:
- For example, the wave height of a sheet with a roof slope of up to 15 degrees is no more than 20 mm. In this case, according to the standards, the crate must be continuous, made of edged boards with a thickness of 20-30 mm.
- With the same roof slope (15 degrees), if a profiled sheet with a wave height of more than 35 mm is laid, then the crate can be in increments of 300 mm.
- If the height of the profile wave is more than 44 mm, and the roof exceeds a 15-degree slope, then the boards on the crate can be used with a thickness of 30 mm or more and fastened in increments of 350-500 mm.
It should be noted that when constructing a flooring from a profiled metal sheet, a certain pattern can be traced: the smaller the slope of the roof slope, the greater the overlay of the upper sheets on the lower ones should be. This is required to protect the roof from leaking at a slight slope, blowing water under the sheets and tearing off the roof in strong gusty winds.
One of the main parameters in the characterization of the roof is the angle of inclination of its slopes relative to the horizontal plane, or slope. A number of important operational and structural features of the roof depend on the value of this indicator. Therefore, the slope is not chosen arbitrarily, but depending on the climatic conditions of the area, the wind rose, the amount of precipitation, the design of the truss system, roofing and the length of the slopes. We will look at roofing material such as profiled steel sheet or corrugated board and the minimum roof slope recommended by the building codes.
The slope is usually measured in percent or degrees, while the ratio between them is determined from the tables, 1 ° = 1.7%, but 45 ° = 100%.
With the maximum slope of the roof, the snow load is reduced to a minimum and rainwater is drained easily and quickly, but at the same time, the windage of the roof increases many times over. With minimal slopes, windage can be neglected, but the requirements for tightness and watertightness of the roof increase, and the load created by snow pressure also increases. Therefore, for different roofing materials, optimal and minimum slope values \u200b\u200bare recommended.
Table of ratios of degrees and percentages of slope
For a builder who independently determines the angle of inclination of the slopes of his roof, it is enough to recall the basics of trigonometry. So, the height of the ridge will be equal to the opposite leg, half the width of the ceiling (the width of the house) or the lower puff will be equal to the adjacent leg, the length of the slope will be the hypotenuse. We should determine the angle between the hypotenuse (slope) and the adjacent leg (overlap).
By dividing the height of the ridge by the length of the rafter leg or slope, we get the sine of the angle of inclination. Further on the table or using a calculator, you can easily determine its value in degrees or percentages. You can also use cosine or tangent to define an angle. These are the ratios of half the width of the overlap to the length of the slope or the height of the ridge to half the width of the overlap, respectively.
L - hypotenuse, H - height of the ridge, B / 2 - half the width of the overlap
There is another way to determine the slope of the roof, which is based on the fact that the height of the ridge (speaking of the height of the ridge, here and earlier it meant the distance from the ceiling to the upper point of intersection of the rafters) is divided by half the width of the ceiling and multiplied by 100. Next, the slope is determined according to the table.
Thus, when designing a truss system, we have two given values: the width of the house and the desired angle of inclination. Next, using simple trigonometric functions, we calculate the distance from the ceiling to the ridge and the length of the rafters.
Characteristics of profiled sheet
A profiled sheet, or corrugated board, is a building material that is a cold-rolled steel sheet, stamped in the form of a corrugated or trapezoidal profile. Next, the steel is coated with a layer of zinc or aluminum for anti-corrosion properties. At the final stage of production, the product is cut, and the sheets are painted by spraying a polymer powder dye using an electrostatic field, followed by heat treatment. The result is a galvanized steel profiled sheet with a protective polymer coating, which can have different colors.
Profiled sheets are used as enclosing or bearing material in the construction of walls and roofs, as well as fences and other structures. The wall sheet is indicated by the letter "C", the roofing sheet is "H", the universal one is "NS". The length of the sheet can vary from 0.1 to 12 meters, the width - from 1.035 m to 1.8 m. The useful width differs from the overall width by 4 - 5 cm due to the overlap of the sheets during installation. The thickness of steel is different and ranges from 0.4 to 1 mm.
The most common corrugation shape is a trapezoid
The height of the corrugations (waves or profile trapezoid) for roofing profiled sheets is 20 or more millimeters. For small spans or with a continuous crate, it is also possible to use smaller corrugations with a height of 8 mm or more.
The minimum slope of a profiled sheet roof implies frequent or continuous lathing; with an increase in the slope, the lathing step also increases. The maximum step for corrugated roofs is up to 4 meters.
The crate for the profiled sheet is used differently, more often not solid
Roof slope from profiled sheet according to SNiP
Building codes recommend making a roof slope of corrugated board equal to 20 ° or 36.4%. At the same time, the minimum slope for industrial and economic facilities with a bearing profile must be at least 8 ° or 14.1%. For residential facilities and facilities intended for permanent human use, the minimum slope is assumed to be 10° or 17.6%.
At the same time, it should be taken into account that with a decrease in the angle of inclination of the slopes, the transverse and longitudinal overlap of the sheets increases, i.e. their effective area decreases. With a slope of more than 35 °, the overlap is at least 150 mm, if the slope is from 15 to 30 degrees - at least 200 mm, if the slope does not exceed 15 ° - the overlap is at least two waves long, while the joints should be treated with silicone or thiokol sealant. It is necessary to process both transverse and longitudinal joints.
It is better to entrust the installation of corrugated board to professionals
Decking is a good building material in terms of price / quality ratio, in addition, it looks good and has a wide color palette of coatings in its assortment. However, the quality of its installation and the skill of the roofer, the selection of materials for the roofing cake, insulation and waterproofing play a very important role. Therefore, trusting roofing work with profiled sheets, as well as the choice of the roof itself, is necessary only for competent specialists and experienced professionals with good recommendations.
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Today, in the vast market for roofing materials, profiled sheet has gained great popularity. It is successfully used in both industrial and private construction. In addition to high performance, corrugated board also has a beautiful appearance - the ability to order a sheet of the right size greatly facilitates its installation. The only thing is that you need to observe the correct slope of the roof from the profiled sheet.
Consideration of the minimum slope is necessary not only from the standpoint of seeing the image of the future home. This issue is also relevant in connection with the climatic conditions of the area of the proposed construction.
Advantages of profiled sheet as a roofing material
Let's mark it right away
- high strength,
- operational reliability,
- ease,
- aesthetics.
It can be used with a slope of at least 8 ° (1: 7) according to SNiP. The slope of the roof in this case does not allow rainwater to overflow through the waves of corrugated board. The same applies to the effect of snow load. This is a significant advantage, since it allows roofing work to be carried out all year round, regardless of the vagaries of nature. Profiled sheets are adapted for use in adverse conditions. He is not threatened with corrosion after rain, as well as burnout under the rays of the sun.
This building material is widely used to cover large pitched roofs. The increased rigidity of the ribs prevents it from deforming, it is durable and economical.
Basic rules for roof construction
The method of laying the material when installing the profiled sheet on the roof to a large extent determines the slope of the roof from the corrugated board. When working with it, you should adhere to certain features of laying and operating rules.
What should be the slope of the roof
The minimum slope of a roof from a profiled sheet for residential buildings is considered to be - 12 °, -20 ° is considered optimal, and from a corrugated board for industrial buildings it is equal, respectively, - 8 °.
These limits may change depending on the number of layers laid down. For example, if laying is carried out in two layers, then the slope must be increased in order to prevent various sediments from accumulating at the joints of the profile sheet. To protect them from precipitation, the joints are coated with a hermetic filler.
- In the case when the slope of the roof is less than 14 °, then when laying the overlap of adjacent sheets in the horizontal direction should not be less than 20 cm.
At the junction with the valley and the ridge, sealing is carried out using special profiled seals. Such a gasket does not allow precipitation to fall under the roof elements during severe weather, such as heavy rain. When it is installed like this, a gap is left sufficient for air movement.
It should be especially noted that in the process of roof overlapping with an angle of inclination of 12° or less, the joints of horizontal and vertical overlaps of profile sheets are sealed using silicone sealant.
- 15–30°, overlap is required in the range from 15 to 20 cm.
- More than 30° - allowed overlap from 10 to 15 cm
How the profiled sheet is attached to the roof structure
For fastening corrugated board to roof structures made of wood, special self-tapping screws for roofing are most suitable, which are made at the end with a drill and equipped with a neoprene gasket. Unlike here, the fastening is carried out only at the bottom of the wave.
The self-tapping screws used are 4.8 x 35 mm. To fix the skates in the upper part, larger self-tapping screws are used, 8 cm long. You should also take care of vapor and waterproofing, and the presence of a gap that provides ventilation for the space under the roof. These requirements are mandatory.
Which crate to choose
In industrial and industrial facilities, the roof is usually flat or shed. For flat roofs, load-bearing corrugated board is used, having a profile height starting from 4.4 cm. It is welded onto a metal frame. Then an unexploited flat roof is arranged over it.
For pitched roofs, they mainly take a profiled sheet, the profile height of which is not less than 3.5 cm, and the sheet thickness is about 0.6 / 0.7 mm.
It is important to know that the higher the profile, the more load it can withstand.
The size of the crate determines the wave height of the used sheet and the slope of the roof from the profiled sheet.
- If corrugated board of the C20 brand is used for work, then with a slope of less than 15 °, a continuous crate is performed, and the overlap of the sheets is in two corrugations.
- With an angle of less than 15 ° and the material used is C35, it is recommended to choose a step of 30 cm for the crate, with an overlap in one wave. In some individual cases, a step of 65 cm is allowed.
- Another brand of profiling sheet - C44 and more. In this case, the distance between the laths is increased to 500 mm, possibly more. If the steepness of the slope exceeds 15 °, the structure for the sheets is performed in increments ranging from 350 to 500 mm, depending on the height of the corrugation of the corrugated board.
- With any slope of the roof, it is also supposed to arrange a drainage system, which will be "responsible" for the correct removal of precipitation and excess moisture from the roof surface. Its slope should be organized so that when installing the internal catchment system, it is directed towards the funnels for receiving water, or towards the gutters, if there is an external catchment area. It is also important that the optimal slope of the roof from the profiled sheet is ensured.
- When organizing a slope of up to 10 °, it is recommended to lay special membrane coatings that are able to reliably protect the roof from moisture and damage to materials.
It is important to know that if the slope of the roof decreases, then the ventilation gap must be increased accordingly.
- When installing profiled sheets, you must follow all the requirements for laying conditions, fastening spacing and the recommended overlap size. In particular, they are mounted with an overlap on the base to ensure that the under-roof space is protected.
Neglect of any of the required criteria can lead to disastrous consequences.
The angle of inclination of the slopes with respect to the horizontal plane is an important indicator for the roof. It affects the design and performance and is therefore selected after analysis of the finished roofing. For example, a profiled sheet imposes special requirements on the slope of the roof.
The concept of roof slope
The slope of the roof refers to the intensity of the slope of the roof in relation to the horizon. This indicator is denoted by the Latin letter İ and is expressed both in degrees and as a percentage.
In the documentation, the roof slope is usually expressed as a percentage, although there are no strict requirements for designating its size.
Tilt measurement
The angle of inclination is determined by an inclinometer - a device with a division scale - or by calculation using a formula from a mathematics course.
Inclinometer - a tool with an axis, a pendulum and a division scale
A special tool is used only in exceptional situations; usually, to calculate the roof slope, they resort to the mathematical formula i \u003d H / L. i is the angle of inclination of the slope, H is the vertical height (from the ridge to the eaves), L is the interval from the bottom to the top of the slope horizontally (laying length).
The angle of inclination of the roof is the result of dividing the height of the roof by the length of the laying
In order to convert the value of the slope of the roof into percentages, it must be multiplied by 100. And the resulting percentages can be converted into degrees using a special table.
Table: the degree of slope of the roof in two measures
| degrees | % | degrees | % | degrees | % | ||
| 1° | 1,7% | 16° | 28,7% | 31° | 60% | ||
| 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% | ||
| 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° | 38,9% | ||
| 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% | ||
| 13° | 23% | 28° | 53,1% | 43° | 93% | ||
| 14° | 24,9% | 29° | 55,4% | 44° | 96,5% | ||
| 15° | 26,8% | 30° | 57,7% | 45° | 100% |
Roof pitch measurement example
Let's say that the height of the roof is 2 m, and the laying length is 4.5 m. This means that the calculation of the roof slope is as follows:
- i = 2.0: 4.5 = 0.44.
- 0.44×100 = 44%.
- 44% \u003d 24 ° (according to the table for converting percent to degrees).
Video: calculating the angle of inclination of the ramp
The minimum threshold for the slope of the roof from corrugated board
The minimum roof slope limit is determined by the type of roofing material.
When the roof is slightly tilted, the topcoat may not turn the slopes into a kind of sail. But he will have to be as durable, airtight and impervious to moisture as possible.
The extreme value for the angle of inclination of the roof from the profiled sheet in residential buildings is 12 °. And a “reasonable” slope of a roof made of corrugated board is considered to be 20 °, which ensures that the roof will be a reliable structure. The roof of non-residential premises is suitable for an angle of inclination equal to 8 °.
These norms may be invalid only in the situation of mounting several layers of material on the roof. Suppose, when installing building materials in two layers, the slope of the roof is necessarily increased, otherwise water will seep into the places where one sheet is combined with another.
The minimum slope of the profiled roof is 8 degrees
The smallest roof slope affects the construction of the truss system and lathing, as well as the laying of corrugated board.
The steeper the slopes, the more racks are used
A wooden structure for profiled sheets on an almost flat roof is created with tiny gaps or absolutely without them. The material is laid out on the crate with a relatively large overlap, which reduces its effective area.
Compared to a slope of 15–30°, which requires sheets to touch 2–3 cm, a slope of 10° forces the builder to impose one metal profile on two waves of the other.
There is no maximum limit for the angle of inclination of the corrugated roof. Profiled sheets can even cover slopes inclined by 70 °, if the weather conditions in the area where the construction is being carried out do not contradict this.
Permissible slope of the roof with profiled sheets
To find out what is the permissible angle of inclination of a roof covered with corrugated board, pay attention to the following few points:
Imagine that the house is located near Novgorod, where the area is called the third snow, and the roof is planned to be built from materials such as:
- professional sheet C21 with a thickness of 0.6 mm and a working width of 1 m, 1 m² of which weighs 5.4 kg;
- basalt slabs with a thickness of 10 cm and a density of 150 kg / m³, which increases the mass of raw materials to 15 kg;
- pine timber with a section of 20 × 20 cm, laid every 65 cm, which is why the weight of 1 m² of the crate will be 28.3 kg;
- additional materials, the weight of which can be equated to 3 kg.
It turns out that the actions for calculating the angle of inclination of the roof from the profiled sheet are as follows:
- The mass of the roof is determined taking into account all materials (5.4 + 15 + 28.3 + 3 = 51.7 kg / m²).
- The mass of the roof is found, taking into account the coefficient that makes it possible to change building materials under the influence of various factors (51.7 kg / m² x 1.1 \u003d 56.87 kg / m²).
- Using a special map, they will find out what is the snow pressure on the roof in the region of its construction. In the Novgorod region, the snow load is equated to 180 kg / m². This value is multiplied by a correction factor µ depending on the degree of roof slope. With a minimum slope (up to 25°) it is 1, with a maximum (from 60°) - 0, and with an average (25–60°) it is determined by the formula µ = (60° - α) x (60° - 25° ), where α is the desired roof slope.
Each of the eight regions has its own snow load index.
- On a map indicating the wind load for each region of Russia, find the value for the area near Novgorod. It belongs to the Ia wind region, which means it is characterized by a wind pressure of 23 kg / m².
The calculated value of wind pressure is in the range from 24 to 120 kg / m³
- According to the formula W \u003d Wn x Kh x C, the wind load acting on the roof is calculated. Wn is the ultimate load for the selected area, Kh is a coefficient dependent on the height of the house, and C is the aerodynamic coefficient, which is determined by the angle of the roof and ranges between 1.8 and 0.8. It turns out that in this situation the wind load is 18.4 kg/m² (23 x 1 x 0.8 = 18.4 kg/m²).
- It is summarized that the pressure on the roof, caused by the weight of the materials and the effect of wind with snow, is 255.27 kg / m² (56.87 + 18.4 \u003d 180 \u003d 255.27 kg / m²). This means that the C21-1000-0.6 profiled sheet with a bearing capacity of 253 kg / m² (with a step of the support beams of 1.8 meters) needs such an angle of inclination that the load is less than this value. That is, it is necessary to stop the choice on a roof slope of more than 25 °.
- Taking note that a slope of more than 60 ° is unreasonable, determine the permissible angle of the roof. To do this, the required value of the correction factor (180 (60-α) (60–25) + 75.27 \u003d 253) is inserted into the formula for calculating the roof load. It turns out that under given conditions, the angle of inclination of the roof should be 26 °, and preferably 30 °, so that the roof is more reliable.
Table: the value of the height coefficient for determining the wind load
Selection of corrugated board, taking into account the degree of slope of the roof
Under the slope of the roof, the material has to be specially selected. This is due to the different parameters of the sheets (width, height and thickness). For example, the profiled sheet of the H75 brand is distinguished by a significant thickness (about 1.2 mm) and an impressive profile height (7.5 cm), which requires that it be used only in the construction of a roof with a slope of at least 8 °.
The parameters of the profiled sheet of different brands vary greatly, which means that the material is not suitable for roofing with any slope slope
Table: the influence of the roof slope on the grade of the profiled sheet and its installation
| The degree of slope of the roof, expressed in degrees | Brand of metal profile for roofing | The step between the elements of the crate | The amount of overlap of sheets in one line |
| More than 15° | NS-8 | - (without gaps) | Two combs |
| Up to 15° | NS-10 | - (without gaps) | Two combs |
| More than 15° | 30 cm | One comb | |
| Up to 15° | NS-20 | - (without gaps) | One comb |
| More than 15° | 50 cm | One comb | |
| Up to 15° | S-21 | 30 cm | One comb |
| More than 15° | 65 cm | One comb | |
| Up to 15° | NS-35 | 50 cm | One comb |
| More than 15° | 1m | One comb | |
| Up to 15° | NS-44 | 50 cm | One comb |
| More than 15° | 1m | One comb | |
| At least 8° | H-60 | 30 cm | One comb |
| At least 8° | H-75 | 40 cm | One comb |
Thinking about what the slope of the corrugated roof should be, they turn to a rather large list of requirements and norms. But there is also a table of recommended values, which reduces the work of determining the angle of inclination of the roof to a minimum.
The roof of any building is an important element. For the installation of the structure, high-quality and high-strength building materials are selected. The most popular and used material among consumers can be called corrugated board. The angle of inclination of the roof must be chosen, taking into account the appearance of the building, SNIP, design and much more. Many factors influence the choice of roof slope.
Factors affecting the choice of slope
It should be noted three main reasons that have a significant impact on the choice of the angle of inclination of the structure as a percentage, these are:
- wind strength and direction;
- the amount of rain;
- snow cover height.
A small slope angle has its advantages and disadvantages. The advantage of a slight slope is resistance to strong gusts of wind. The downside is the additional thorough sealing of all joints of the coating in order to avoid leakage during heavy heavy rains (water from such roofs runs off much more slowly). In some regions, the winter is too long, a large layer of snow accumulates on the roofs. From roofs, the slope of which is insignificant, the snow layer moves out much more slowly.
When the roof structure is not strong enough, it leads to the collapse of the coating. You have to clear the snow yourself. To avoid such unpleasant situations, all structural elements should be strengthened. It is necessary to install additional elements to strengthen the rafters. It is necessary to clean the roof from the snow layer in a timely manner.
The choice of a profiled sheet for covering a shed roof should be approached carefully: the durability of the structure depends on this. An important role is played by the configuration of profiled sheets. The most rigid are products with a high wave. Professional sheets of universal use and products for walls have a less rigid structure. It is equally important to take into account financial possibilities when purchasing the right material.
Characteristics
An important role in choosing the angle of the roof slope is played by the technical characteristics of the profiled sheet. For the manufacture of this material, special steel is used, 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 and varnish substance. Next, the processed sheet is processed on a special machine. After that, it takes on a wave-like shape. Waves can be in the form of a trapezoid or a rectangle. This is necessary to increase the strength, reliability of the material. There are three types of decking. It can be roofing, wall and mixed.
Distinctive features of this material are in the thickness used for its production of steel, low profile height, affordable cost. This type of building material is the best option for finishing wall surfaces, making fences and roofs of small sizes. For the manufacture of a bearing type of material, steel sheets are used that are thicker than the wall version of corrugated board. The peculiarity of this building material is the additional stiffeners.
Thanks to the additional ribs, the bearing corrugated board can withstand much higher loads. The scope of such building material is quite wide. It is used in the process of building garages, hangars and other buildings, as well as for covering large roofs. Due to the excellent technical characteristics, the universal type of profiled sheet can be used in construction for any purpose.
Corner
There are special building codes that clearly state the optimum standards for the installation and creation of various building coverings. To cover a roof made of profiled sheet, the minimum angle of inclination of the structure is about 8 degrees, based on building codes. In this case, a continuous or frequent crate should be installed. According to professional builders, a flatter design can also 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 board. 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 board.
low-slope
With this type of roof slope, material consumption increases significantly. This leads to additional financial costs. Consumption is due to a large overlap of one sheet on another (horizontally and vertically) of the order of 20 cm. In addition, it is necessary to additionally protect the rafters from moisture. To do this, it is advisable to use a special membrane material. This measure is necessary to ensure the waterproofing of the coating. The angle of inclination of a low-slope structure is usually less than 14 degrees.
medium slope
This is a more economical installation option. The angle of inclination of a medium-slope roof is from 15 to 30 degrees. At the same time, the overlap of one sheet of corrugated board on another is much less. This allows you to significantly save on building materials. Consequently, financial costs are reduced.
Steep
The slope of such a roof structure is more than 30 degrees. Installation of a professional flooring is made with the minimum overlap. This type of installation of the roof structure of the building is the most economical and less costly.
Dependence on the slope of the roof
In the process of construction, flat roofs are most often installed on industrial buildings. Roofs with one slope are installed on outbuildings. Residential buildings, as a rule, have gable, four-slope and hip roofs. Installation of a profiled sheet coating is carried out on a solid, reliable base that can withstand a significant weight of the structure. With the help of the base, the weight of the corrugated board is evenly distributed over the entire surface of the roof. Choose the type of crate should be depending on the slope of the roof.
In the process of mounting low-slope structures coated with a profiled sheet, the profile height of which is about 20 mm, for the construction of the crate, an edged board with a thickness of about 3 cm should be used. In order to make the structure support stronger and more reliable, a solid base should be mounted. For the installation of low-slope roofs covered with corrugated board with a profile height of more than 35 mm, it is permissible to build a base in the form of a grid. The distance between the boards in such a crate should not exceed 30 cm. When installing a medium-slope roof coated with profiled sheets, the profile height of which is about 44 mm, the best option for mounting the base would be to use a board with a thickness of about 3 cm. The allowable 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 minimum 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. This eliminates the need for sealing.
- The load on the foundation and building structure is much less than on roof models with a large slope angle.
The greater the angle of the roof slope, the greater the load on the foundation and building structure. As a result, material consumption increases.
Flaws
There are quite a few disadvantages of this roof option. During heavy rainfall, moisture drains from such a roof more slowly than from steeper roofs. Water will seep into joints and cracks. Therefore, the construction of a roof with a slight slope requires careful sealing (especially joints and overlaps of profiled sheets).
To cover this type of roof, the best option would be to use only load-bearing corrugated board, which is more durable and has a high profile. Covering a steep roof can be made from any corrugated board. Suitable universal, wall and bearing profiled sheets. Precipitation on such coatings will not linger.
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 on another; additional sealing of joints and overlaps will be required. However, if the angle of the roof slope is from 12 to 15 degrees, it is quite possible to do without sealant. Therefore, the optimal angle for the slope of a roof made of corrugated board is an angle from 12 to 30 degrees.
Despite the fact that a fairly large number of boards will be required to install a steep roof, significant savings will be obtained on the purchase of corrugated board. You can purchase less expensive profiled sheet options with a small profile height. With a minimum angle of roof slope, the installation of a residential attic is absolutely impossible. Installing a roof with a minimum angle of inclination involves the installation of a more complex structure of the truss system. The design must be stronger and more reliable in order to withstand a significant load and heavy weight. You will have to reduce the step 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 from a profiled sheet, it is important to take into account many different nuances. The climatic conditions of the area where the construction of the building is planned play 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, the approximate height of the snow cover. Roofing material must withstand the effects of weather factors.
For regions where strong winds prevail, the best option is to install a roof with a minimum slope. This will avoid the destruction of the structure during strong gusts of wind. However, it should be noted that flat roofs can also suffer in this case. Therefore, it is necessary to correctly calculate the optimal variant of the minimum roof slope angle for a given area.
In addition to the wind load, the calculation of the angle of inclination of the roof of the building is significantly influenced by the snow load. It is no secret that in many areas a significant amount of snow falls in winter, forming a heavy snow cover. Even the most durable construction of the truss system cannot always withstand such loads. Therefore, the best option in such areas is the installation of steep roofs. It is possible to install a roof with a minimum slope, but in this case it will be necessary to clear the roof of snow cover in a timely manner in order to avoid the destruction of the roof.
Installation nuances
Installing a roof with a minimum slope is most popular in regions with warm climatic conditions and low rainfall. The roof structure is mounted taking into account the climate, additionally equipped with thermal insulation and ventilation. This is necessary to reduce the heating of the room and get rid of condensate. These operations are carried out in accordance with generally accepted instructions, using high-quality raw materials.
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