Minimum roof slope for metal tiles. Selecting the minimum angle of inclination of a metal tile roof

Choice correct angle roof slopes are not only an aesthetic task, but, to a greater extent, a practical one. After all, the performance of the coating, the protection of the building from atmospheric influences - primarily precipitation, the durability of the structure and the consumption of materials - will depend on this parameter. Minimum slope Metal roofing, due to a number of material features, is more important than for other materials and is less flexible.

First of all, you should decide what a slope is, why it is needed at all, and how to cover the roof with metal tiles. The slope is the angle between the floor plane and the rafters.

It is calculated using common fraction in the following way:

i = h: (1/2L), where:

i – slope

h – height of the ridge above the ceiling

L is the width of the building, or the distance in width covered by a given section of the roof (for broken roofs, where the slope can change within one slope)

For example, with a building width of 8 m and a ridge height of 3 m, the slope will be equal to: 3:4 = 3/4, or 0.75. To express as a percentage this value multiplied by 100: = 75%

However, the angle is sometimes expressed in degrees - both systems have equal movement.

In this case, the real geometric value of the slope is displayed in degrees - the angle between the rafters and the ceiling.

These values ​​do not coincide, which is why confusion and errors often arise among builders, and sometimes among those who compile instructions.

Knowing the sides of a triangle, converting one quantity to another is not a problem.

However, for those who do not like to bother themselves with calculations for metal roof tiles, there are special conversion tables, like the following:

Degree	Percent	Degree	Percent	Degree	Percent
1	1,8	16	28,7	31	60,0
2	3,4	17	30,5	32	62,4
3	5,2	18	32,5	33	64,9
4	7,0	19	34,4	34	67,4
5	8,8	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	19,4	26	48,7	41	86,0
12	21,2	27	50,9	42	90,0
13	23,0	28	53,1	43	93,0
14	24,9	29	55,4	44	96,5
15	26,8	30	57,7	45	100

Although the roof is designed together with the entire building, there is still some room for maneuver until the creation of the rafter system, whether the slope of the roof is calculated from metal tiles, slate, or any other material.

If the foundation and walls have a certain margin of safety, then, at least within the same roofing material, the shape and slope of the roof can be varied.

Since the width of the building is a fixed value, and the length of the rafters is determined by the distance between the ridge and the point of support on the wall, the ability to change the angle of the roof remains only with the height of the ridge.

When the owner of the building has determined which slope he considers optimal for himself, the following table will help calculate the height of the ridge

To get the result, you need to take half the width of the overlap, find the desired angle in degrees in the table, and multiply it by the coefficient in the corresponding line.

The resulting value will be the required height of the ridge. All these calculations are applicable to a shed roof - but then you need to take not half the width of the roof, but the full one, and instead of the ridge the height of the larger one will appear external walls.

The same is true for hip (hatched) roofs, but in this case the slope of the end slopes is measured from the middle of the wall to the point where the slope rests on the end of the ridge.

There is a simple way to determine the required height of the ridge “in place”. It is necessary to put marks on each of the external walls along which the slope will go (it is better that they are located in the center of the length of the walls).

A cord is sequentially stretched between opposite marks; you can mark a line along it with chalk. Exactly in the middle of the cord (measured with a tape measure), you need to install a bar perpendicular to the ceiling (checked with a corner).

Now, by moving the string up the plank, you can, by measuring the angle at the wall, determine in what position of the string the required slope will be achieved. A mark is placed on the bar at this point.

If you now saw off the strip in this place, you will get a template that will allow you to cut without problems required quantity ridge supports of the required size.

If supports are not expected, then the same operation can be carried out at each end, fasten the measuring rods, and stretch the cord along their top. He will indicate the required joining height of the rafters.

What is affected by roof pitch? Two groups of factors can be distinguished - positive and negative, which are caused by its increase.

Positive:

• Rain hits the roof at a large angle, which virtually eliminates the possibility of it getting between the covering elements, as well as under the overhang of the slope
• With large slopes, the snow load on the roof is reduced, and at angles of 45 ° it is not taken into account at all. Eliminates the need for a snow retention system
• The main force load on the roofing material is “shearing” in the direction of the slope, which can be handled quite reliably by standard fasteners - nails and self-tapping screws
• Possibility of creating under-roof spaces, attics of larger area and with more correct geometry

Negative:

• Increased consumption of roofing material - for example, changing the slope from 15 ° to 45 ° on a simple roof will increase the required coverage area by more than 20%
• Increasing weight of the roof - after all, the weight of the covering and supporting structures will increase
• Large windage and, accordingly, wind load
• The complexity of organizing a drainage system - on linear meter sewer have to big square roof, the water flows down it at a higher speed. It is not a fact that for any slope it will be possible to select the appropriate section of the drainage tray - and this will require a drainage system in several tiers

Ultimately, the truth is somewhere in the middle - and here each homeowner is tied to his own climate zone,financial capabilities and other factors.

But, if a metal roofing device is chosen, the manufacturer’s instructions impose certain restrictions.

Different companies indicate different acceptable values ​​- from 12° (and even 10°) to 15°.

Since the material is relatively new, there are no SNiP requirements for this parameter for it. But practice suggests that this angle should still be at least 14°.

If the manufacturer does not stipulate special restrictions on the maximum angle, it can be accepted at any angle.

However, “medium” angles are the most ineffective in terms of snow load. It has been experimentally proven that in winter time snow accumulates most actively on roofs with a slope of 20-35°

This value is determined by the specifics of the material. The strength of metal tiles is its flexibility, which allows you to form quite complex designs for do-it-yourself metal tile roofing.

But this is also its weakness, since with a small slope or a large snow load, even a powerful supporting system cannot save it.

For example, installation of a valley when roofing with metal tiles is carried out over a continuous sheathing. However, at small angles, even this does not save.

After all, since the groove is the internal junction of the slopes, snow pockets can form here in winter. The increased mass of precipitation puts pressure on the metal and bends it, opening access to the under-roof space.

In the event of a thaw and subsequent cooling, frozen water fixes and widens the cracks, promoting further leaks.

A small slope contributes to the same effect in heavy rain - the water does not have time to go down the slope, and has high pressure on the roof. Metal tiles with a high wave height are less susceptible to this - their bending strength is higher.

All metal tiles are directional material, that is, they can be mounted in only one position. Therefore, a special rubber seal is placed at the bottom of each sheet, which somewhat reduces the effect of precipitation.

However, with intense exposure, sealing should be done less frequently than once every 3 years, otherwise it cannot be avoided overhaul roofs.

But the flexibility of the metal tile also affects its resistance to wind loads - if they are directed into the plane of the sheet and fall on a reliable sheathing - there will be no problems.

But if gusts come from the bottom or side, creating a tearing effect, sooner or later the material will bend or come off. That is why the protrusion beyond the edge of the sheathing is made so small - 40-50 mm, and the wind strips are attached both from the ends and from the eaves.

Summarizing all the factors, we can say that the minimum slope required by the instructions for installing a metal tile roof is an ideal value, assuming that all the requirements for the installation technology will be met flawlessly.

By setting a larger slope, you will, of course, have to spend money on an increased amount of material. But at the same angle of 45 degrees, you can save on installing expensive snow guards, and be calm about possible excessive snow and rain loads on the roof, getting under the overhang of the wind and blowing rain splashes there.

Metal tiles are sheet (0.38-0.55 mm) material made of galvanized steel, aluminum or copper alloys, produced by cold pressing. Profiling metal base with application of polymer protective coating made it possible to create an imitation of masonry ceramic tiles. The low weight of the sheet (about 5 kg) simplifies installation work.

The purpose of the roof is protection from exposure environment, drainage of melt and rain water, thermal insulation of the house. Correct calculation of the structure, slope angles, and compliance with assembly rules guarantee:

• comfortable climate inside the building,
• long life of the house without repairs.

Slope is a degree, percentage or fractional measure of the slope of the slope in relation to the ceiling. It depends on the indicator:

• degree of sediment removal;
• resistance to wind load;
• ridge height;
• roof area;
• weight of the structure;
• financial costs for roofing work.

Units

Manufacturers roofing materials indicate in the installation instructions for their products the recommended minimum roof slope. Units of measurement are different:

• Degree is a common indicator for measuring plane angles.
• Percentage – the degree of deviation of the slope from the horizon. The parameter is adopted in SNiP and SP. The reason is that with the degree measurement system there is a high probability of errors and deviations from the structural plan of the house.

The value 45° is taken as 100%.

Table for converting degrees to percentages:

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	7,0		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	23,0		28	53,1		43	93,0
14	24,9		29	55,4		44	96,5
15	26,8		30	57,7		45	100,0

Sign for calculating the slope of the slope: C = 5: 8 *100 = 62.5%, this corresponds to α ≈ 32°

In relative units - a simplified fractional value of the ratio of the height of the ridge (B) to the foundation (A). In our case: 5:8 = 1:1.6.

Degrees	Relates. unit		Degrees	Relates. unit		Degrees	Relates. unit
1	1/57,29		16	1/3,49		31	1/1,66
2	1/28,64		17	1/3,27		32	1/1,60
3	1/19,08		18	1/3,08		33	1/1,54
4	1/14,30		19	1/2,90		34	1/1,48
5	1/11,43		20	1/2,75		35	1/1,43
6	1/9,51		21	1/2,61		36	1/1,38
7	1/8,14		22	1/2,48		37	1/1,33
8	1/7,12		23	1/2,36		38	1/1,28
9	1/6,31		24	1/2,25		39	1/1,23
10	1/5,67		25	1/2,14		40	1/1,19
11	1/5,14		26	1/2,05		41	1/1,15
12	1/4,70		27	1/1,96		42	1/1,11
13	1/4,33		28	1/1,88		43	1/1,07
14	1/4,01		29	1/1,80		44	1/1,04
15	1/3,73		30	1/1,73		45	1/1,00

Calculation of what the angle depends on

The design of the roof includes the definition minimum angle metal roof slope. For this material, according to SNiP II-26-76*, 20% (≈12°) is recommended. The minimum acceptable angle is 10%. If parameters are less than recommended, sealing of sheet joints is required.

This indicator does not take into account the characteristics of the climate zone and the structural specifics of the house design. More exact value will give the project taking into account external factors exposure and the presence of an attic. Snow load - the effect of snow mass on the roof. The slope angle must be optimal.

Provides:

• minimal snow accumulation;
• integrity of the external ceiling, roofing material, drainage system;
• prevents sudden removal of accumulated snow.

The design of rafters is carried out with the definition minimum mass snow, during which the following occurs:

• Destruction is the value of the maximum snow mass (S), leading to the collapse of the ceiling.
• Deflection is a standard parameter; deformation of the structure occurs, but restoration is possible.

The area of ​​Russia is divided into eight climatic zones. SNiP 2.01.07-85* defines the territorial indicator of the total snow load per 1 m² of horizontal surface (Sg):

Unit	RF zones
	I	II	III	IV	V	VI	VII	VIII
kPa	0.8	1.2	1.8	2.4	3.2	4	4.8	5.6
kgf/m²	80.0	120.0	180.0	240.0	320.0	400.0	480.0	560.0

The calculation is performed using the formula: S = Sg*µ, where

• µ is the factor taking into account the slope of the loaded surface.

Values ​​of µ depending on the angular magnitude (α):

The influence of snow mass, determining the angle of inclination of any roof can be done using online programs calculators on specialized resources.

Standard = S*0.7.

• Wind load is the pressure of air flows on the eaves overhang and slope.

The minimum angle of a metal roof is determined by the wind influence on the structure. Factors influencing the number:

• climatic conditions of the area in which construction is taking place;
• building height;
• type of terrain.

According to SNiP 2.01.07-85*, wind impact is defined as the sum of the components:

• Pulsation force is an indicator applicable to buildings over 40 m.
• Design value of the average component of wind force at height z, Wр = Wо*k*C.

The Wo standard is a constant value obtained empirically on the territory of Russia.

Windy areas
	kPa	kgf/m2
Ia	0.17	17.0
I	0.23	23.0
II	0.3	30.0
III	0.38	38.0
IV	0.48	48.0
V	0.6	60.0
VI	0.73	73.0
VII	0.85	85.0

k is a coefficient that adjusts the wind load depending on the height z and the type of terrain.

C is the coefficient of aerodynamic influence, depending on the slope (α), the ratio of the roof vertical to the span width and the wind vector.

C1 – slope parameter from the windward direction. C2 – from leeward. A positive value is the impact on the slope, a negative value is from the surface.

Table for gable roof:

Coefficient	α, deg	Roof/building height
		0	0.5	1	More than 2
C1	0,0	0	-0.6	-0.7	-0.8
	20,0	0.2	-0.4	-0.7	-0.8
	40,0	0.4	0.3	-0.2	-0.4
	60,0	0.8	0.8	0.8	0.8
C2	≤ 60	-0.4	-0.4	-0.5	-0.8

Intermediate values ​​are determined by interpolation.

The last table confirms the effect of slope under wind load. An increase in the parameter increases the “windage” of the roof, and there is a possibility of the structure overturning. Decrease in indicator - the wind tends to lift and tear rafter system. Calculations of forces due to the influence of natural factors should reveal the minimum and optimal angle.

Calculation of the minimum angle of inclination mansard roof performed if attic space it is planned to be converted into residential. The room must have a sufficient ceiling height, which entails an increase in the slope of the slope.

Determining the minimum permissible angle takes into account:

• roof shape and type of rafter system;
• the desired height of the room (according to SNiP no less than 2.5 m);
• span length.

Approximate calculation of the minimum roof slope using the example of a gable roof:

• a is the distance from the ridge to the rafter, b is the vertical parameter of the room. Distance from ceiling to ridge: a + b;
• (a + b) : ½ c – slope in relative units (above is the conversion table).

Example: a = 2.5 m, b = 2.2 m, ½ *c = 5 m; a + b = 4.7 meters. For inclination angle pitched roof the span length is not multiplied by ½.

Value: 4.7: 5 * 100 = 94%, corresponds to α = 44° according to the table. In relative units: 4.7/5 = 1/1.06.

More accurate calculations can be made using the Pythagorean theorem using trigonometric function: tan (α) = (a + b)/ ½ s = 0.94. Using the Bradis table we find empirical data. Determination of the minimum slope of the tiles must be carried out taking into account the influence of wind force and snow mass.

How long a house will last and how long its roof will last depends directly on what kind of roofing material will be used. Naturally, it is also important how the building will look externally, as well as how environmentally friendly the roof will be. Nowadays, metal tiles have become the most popular material. It has high resistance to impact external environment, intensive loads, and also has good bearing capacity. Naturally, in addition to this, for long-term service, you need to correctly select the minimum angle of inclination of the metal roof. The article describes which optimal parameters to use for this characteristic.

Source dom.germanovich.com

What are the advantages of metal tiles

This material has a number of advantages:

Metal tiles light in weight. For one square meter falls from five to seven kilograms. It is used to cover the roof, which has a complex structure. Thanks to its lightness, there is no need to reinforce the rafters. This roof does not load the walls and foundation.

Due to the ease of installation of roofing material and the absence of the need for special tools, cost of work installation is relatively low.

This roofing material has wide color palette, so you can choose any of them to suit the overall tone of the building.

The tiles are made from thin sheets of steel, the thickness of which is from 0.4 to 0.7 millimeters. Thanks to her profile, she is able withstand heavy loads.

Anti-corrosion sheet roofing material protected galvanized and polymer protective layer, which is applied to the surface.

The main advantages of the material are durability, low cost and aesthetic appearance.

What is slope

The roof slope is the angle formed between the roofing material and the ceiling.

Source stroim-dom.net

In documents it is indicated as a percentage or degrees. It is calculated by mathematically dividing the distance from the highest point at the intersection of the rafters, which is called the ridge, by one-half of the entire width of the building. The slope of the roof depends on:

what material the building will be covered;

design frame roof and its main parts;

as far as the roof can resist atmospheric phenomena;

price works of master roofers;

weight all layers used.

On a note! If the slope of a metal roof is changed from 22 to 45 degrees, the slope will increase by 20%. And this will significantly affect the cost of roofing materials, as well as the weight of the entire structure. In this case, the slope must be determined during the design of the entire building in order to have an idea of ​​the load on the foundation.

What does the slope of the roof depend on?

For those people who do not understand construction at all, it is very difficult to determine exactly what the minimum roof slope should be. Here you need to take into account natural factors that constantly affect the roof. These include:

Snow layer, which will fall in winter. If the slope is greater, the snow will slide off on its own.

Source ko.decorexpro.com

On our website you can find contacts of construction companies that offer services roof design and repair. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

Ability wind resistance. In regions where winds constantly blow, you need to keep the slope minimal so that gusts of wind glide over the roof and do not create a sail effect.

Since this material for covering a building is very light, sparse lathing is allowed, but when installing rafters, you must strictly adhere to the distance and angle at which they will be installed.

How many degrees should the minimum angle have?

The minimum slope of a metal tile roof is 10 degrees. A slope is allowed that ranges from 10 to 90 degrees. When choosing the optimal slope angle, you need to take into account that at a small degree the space between the roof and the ceiling cannot be used for any economic purposes.

If the largest roof angle is set for metal tiles, then go out onto the roof in order to carry out technical work, it will be very difficult. Moreover, the larger the angle, the higher the ridge is located and, accordingly, the area that needs to be covered increases.

Thus, more roofing materials will be needed, and this will affect the budget. In addition, payments for roofing work will also increase Source bankfs.ru

When correctly calculating the roof slope angle for metal tiles, the calculator must take into account the following aspects:

Roof tile model. It should be noted that most manufacturers indicate the minimum slope of a metal tile roof in the product description.

Which roof view Planned: single or double slope.

How will it be clear the snow from the roof.

Having carried out all the calculations and taking into account the above points, provided that the length of the slope surface is 6 m.p., the minimum slope is set at 22 degrees. Naturally, this result is not indicated in technical documentation. He is being calculated experienced craftsmen in the process of observing roofs already in use.

Carrying out calculations

To determine more precisely what the minimum slope should be gable roof from metal tiles you need to know two numbers:

height from the top of the parapet to the ridge;

width building.

To make the calculation, the distance from the parapet to the ridge is divided by the value of half the wall and the result is the desired angle.

Source builld.ru

To determine the result as a percentage, the resulting number must be multiplied by 100.

Important! In order for the result to be accurate, you need to measure the distance to the ridge not from the surface of the ceiling, since this is a gross mistake, but from the top of the parapet.

Naturally, there are exceptions in construction when the slope is only 10 degrees. But this is done in the case of special construction recommendations. It should be taken into account that with such a slope an increased load is created on the surface when snow falls. This way the sheathing is made continuous. In addition, a waterproofing carpet must be laid on it. Also, special gaskets are placed under the butt sides of the roofing sheets.

Video description

In the video you can see the low angle of the roof:

Conclusion

It is best, when working with metal tiles, to know the instructions from the manufacturers and follow them all unquestioningly. In addition, we must remember that experience cannot be replaced by anything, therefore, everything installation work It's better to trust the professionals. Turning to a reliable construction company, you get speed of work and a documented guarantee.

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Among all modern roofing materials, metal tiles are considered the leader in consumer preferences. Why did this particular roof become so widely used? To answer this question you need to compare technical and performance characteristics metal tiles and other roofing materials.

Parameter	Brief comparative characteristics
	Weight metal sheets fluctuates between 5–7 kg/m2, the spread is associated with different thickness. The corrugated sheeting has the same mass; the differences between both roofs are only in the profile geometry. They only weigh less roll coverings, but they have limited areas of use. All other roofing materials weigh much more. For example, a square meter of ordinary slate can weigh more than 30 kg. The weight of the covering is an important technical parameter; the rafter system depends on it; sometimes the weight of the roof must be taken into account when calculating the foundation of a building.
	For the manufacture of metal tiles, thin sheet steel up to 0.6 mm thick is used. Such sheets can be cut without problems not only by electric, but also by hand. special tools. Disadvantage: significant amount of waste metal tiles when covering complex pitched roofs.
	If the material is made by responsible manufacturers, the thickness and quality of the zinc layer is precisely maintained for finishing outer layers innovative polymer coatings, then the service life can exceed fifty years. But the problem is that consumers do not have the opportunity to independently and objectively control the quality of galvanizing and parameters polymer paints, you have to trust the advertising of manufacturers or distributors. And among them there are quite a lot of unscrupulous ones. In terms of service life, metal tiles are second only to piece natural tiles, but only in the case of high-quality and expensive types coatings
	Despite the efforts of technologists to bring the appearance of metal and natural tiles, the similarity between them, except for the name, is very conditional. Color palette very wide, from natural to blue and other very original colors. This, on the one hand, increases design possibilities architects, and on the other hand, makes the already big difference even more noticeable appearance metal and natural tiles. The presence of the word “tile” in the product name is successful marketing ploy to increase the number of sales. Consumers react positively to such advertising - everyone has real respect for tiles.
	To compare, you need to take the average cost of all price categories, and the spread is quite large. By average cost metal tiles are cheaper only than piece coverings; other roofing materials have lower prices. In fact, you should take into account not only the cost of materials, but also the financial costs of their installation. With such a comprehensive comparison, metal tiles are second only to metal profiles.

If a decision is made to use metal tiles to cover the roof, then to ensure tightness, the manufacturers' recommendations should be strictly followed. They regulate several parameters of the rafter system and slopes, including the minimum angle of inclination.

Metal tiles

Why is the angle of inclination of metal tiles important?

This indicator is important not only for metal tiles, but also for all other types of roofing coverings. What parameters depend on the angle of inclination of a metal tile roof?

1. Step and material of lathing manufacturing. The best option laths for metal tiles are considered to be 20x30 mm slats, the distance between them depends on the characteristics of the profile, but in most cases it is 35 cm.

   

   If the angle of inclination of the slopes is large, then the pitch of the sheathing can be doubled, the load on it is significantly reduced. But you shouldn’t overuse it; during wind, large sheets of area can vibrate a little, which negatively affects the comfort of living and the longevity of the roof.

   

2. The distance between the rafter legs or their linear dimensions . The smaller the angle of inclination of the slopes, the greater the load on rafter legs. Accordingly, they should be made from thick lumber or the pitch between the elements of the rafter system should be reduced. A specific decision is made at the planning stage and takes into account maximum amount individual factors: architectural features of the project, location of the building, financial capabilities of developers, etc.

   

3. Wind and snow loads. The smaller the angle of inclination of the slopes, the more snow accumulates on the roof. The profile of metal tiles does not have a flat back plane; only the lower sections of the tiles located on the lines serve as stops, the step between them is approximately 35 centimeters. Accordingly, continuous lathing cannot be used for this roof to reduce the load and eliminate the risk of deformation. The minimum slope is limited by the thickness of the metal sheets and climatic zone location of the house. As for the dependence of the amount of overlap on the angle of inclination of the metal tiles, we will talk about this parameter a little lower; not everything is as simple as it seems at first glance.

   

4. Consumption of materials. Metal tiles do not belong to the category of budget roofing; every developer wants to save on the cost of the roof. Minimal amount materials required for flat roof, the higher the angle of inclination, the greater the consumption. Pitched roofs with a slope of 45° require twice as much metal tiles as to cover a flat roof of a building with the same parameters. Consumption increases not only for tiles, but also for vapor barriers, wind protection, insulation materials, rafter system materials, hardware, etc.

   

The process of selecting the right roof slope is one of the main activities. On the one hand, it has an aesthetic significance, and on the other, a practical one. This characteristic affects the general operational parameters, service life, and the amount of materials used. The minimum angle of inclination of a metal tile roof has some features that impose their own limitations. We will talk about them further.

Features of roofing material

The fact that metal tiles are so popular among the population in private construction can be explained by its positive aspects:

1. Light weight. Possibility of constructing complex geometric shapes. There is no need to further strengthen the rafter system. There is no high load on the walls and foundation of the house.
2. The installation technology is no different in complexity. Available even without special skills. No specialized equipment required.
3. Big choice color range. Can be matched to any home exterior.
4. The slope of the roof can withstand heavy loads due to the profiled waves.
5. Metal sheets are protected against corrosion by an external polymer coating.

Modern roofing coverings must have high functional and decorative characteristics, since they must provide high level protection and look attractive.

Metal tiles have gained popularity due to their long service life, operational properties and not a high price. However, it has its own characteristics and limitations on use.

During design, it is necessary to clearly understand what minimum roof angle is acceptable. The following will depend on it:

• Possibility of coating with one or another material;
• Design of the entire rafter system;
• Level of snow and wind load;
• Sediment removal efficiency.

Metal roofing can have a very slight slope. This is ensured by the rigidity of the sheets. Another advantage will be the possibility of unhindered removal of sediment due to minimal surface roughness.

What influences the choice?

The angle of inclination of a metal tile roof does not have standardized values. The minimum performance will be influenced by many parameters that need to be taken into account during the design phase of the project.

Wind loads. Calculated based on total area roof, average wind strength in the region of construction. All information on the region can be found in directories or the Internet.

Snow loads. In winter, snow collects on the surface and then slides off under its own weight. If the level is small, then the snow will have to be removed manually to eliminate the possibility of damage to the rafter system under its weight. With steeper slopes, the snow is removed faster on its own. Average level Snowfall in the region can also be found on the Internet or in relevant reference books. The project must be developed with safety margins in order to avoid possible deformations in the event of heavy snowfall.

The angle of inclination of a pitched roof made of corrugated sheets also depends on the type of heating, thermal insulation of the entire structure and the under-roof space. If the level of thermal insulation is insufficient, significant heat loss is observed. This may cause snow to melt and accumulate more slowly. The water will flow down. By performing thermal insulation measures, heat loss is reduced. As a result, snow will accumulate more actively. When calculating the slope without thermal insulation materials, there is a chance that the coating will not withstand increased snow pressure.

The amount of rainfall should also be taken into account. The optimal level will be no less than 22°. With a smaller slope, you will have to lay metal tiles using sealants. It will prevent liquid from penetrating through the joints.

In addition, it is necessary to take into account the shape of the structure. So, for single-slope ones, 20-30° will be ideal, for double-sloped ones - 20-45°.

Minimum slope values

In accordance with the requirements of SNiP, for rafters longer than 6 meters, the minimum angle of a corrugated roof is 14°. It is based on calculations of the average parameters of coating strength and load resistance. Despite this, during project development it is worth paying attention to the manufacturers’ recommendations.

In most cases, manufacturers indicate that the roof angle for metal tiles should be designed at 12°. Some manufacturers have options suitable for slopes of 11°. A decrease in parameters is associated with an improvement in individual technical parameters material – increased rigidity and a smoother surface.

It should be noted that metal tiles can be built in certain areas that do not receive heavy rainfall. A slight slope provides stability, but seriously increases snow load, because the snow doesn't slide down.

Roofs for houses made of metal tiles with minimal parameters allow you to reduce the consumption of materials during the construction process. Such roofs are preferable in southern regions where the amount of precipitation does not exceed normal.

Optimal values

The surface area directly depends on the slope. Steeper structures are not able to retain sediment on the surface, which is quickly removed downwards. However, tall ones have greater windage. In addition, more is spent. From this we can conclude that the higher the roof and steeper the slope, the more expensive it will be.

It must be taken into account that the increased windage of a roof with high ridges does not allow the construction of such structures in regions with strong winds. They are not able to withstand such influences constantly.

The slope, including the angle of inclination of a pitched roof made of corrugated sheets, affects the resistance to loads. To increase the strength of a structure with small slopes, it will be necessary to create more frequent sheathing. It will strengthen the entire rafter system, as well as overall reliability.

Even taking into account the absence of restrictions on the use of metal tiles for steep structures, it is still not very suitable for such structures. At more than 45°, the sheets are capable of sliding down under their own weight. This can be eliminated by arrangement additional points fixation.

Based on many years of construction experience and recommendations from manufacturers, we can say that the most optimal slope of a roof covered with metal tiles will be 22°. Precipitation does not linger on it. Economical to build. Durable and reliable, able to withstand severe wind loads.

How to calculate?

i = H / (1/2L)

i – slope that is calculated

H – size from ceiling to ridge

L – width of the house

The result can be converted into a percentage by multiplying by 100.

The most common values ​​are in degrees. They are calculated based on the trigonometric function arctan. There is nothing complicated, since there are tables for translation.

It is possible to use a similar calculation for two and single-pitched roofs. In the case of a single-pitch option, the full length of the span will be taken into account. If there are unequal slopes, then the distance from the ridge to the ceiling is applied. The angle of inclination should be determined separately from the slopes.

For roofs with complex structures and differences, slope correction factors are used regarding horizontal projections.

Positive and negative sides

When deciding, you need to take into account other factors that may have an impact. They can be positive and negative.

First, let's look at the positive criteria that influence construction.

1. Possibility of arrangement of living quarters (attics) of large areas;
2. At buildings with large values eliminates the possibility of water penetrating into joints and connecting elements. This helps to increase service life;
3. In areas with significant snow precipitation on roofs over 45°, they may not be taken into account. You can save on installing snow guards.
4. By correctly designing the ramp, you can do without the use of special fasteners.

Let's consider the negative points:

1. Increasing the slope leads to increased material consumption;
2. The weight of the roof also increases with increasing level of the slope. This is a direct increase in the load on the rafter system. Strengthening will be required;
3. At sharp corners and at significant altitudes the windage increases. Strengthening is also needed.
4. The drainage process becomes more complex. Required drainage system, having more throughput. Sometimes this is problematic.

Calculation process optimal slope consists in finding compromise solutions that will take into account all the features of the construction and appearance.