When erecting a roof, you should decide on its angle of inclination, which will depend not only on the wishes of the developer, the desired contours and design of the house. Roofing material plays a big role in this parameter. When working with metal tiles, the angle will be different from the possible angle allowed when working with slate or metal.
What affects the slope
There are several factors that have the greatest influence on the choice of a certain angle of a metal roof. Among them we can separately highlight:
- wind load;
- snow load;
- roof shape;
- average precipitation.
To calculate this parameter, it is necessary to know exactly the total area of the slope and the wind force characteristic of a particular region. It’s easy to calculate the area of the slope yourself, but you’ll have to look for the wind force in special reference books. When erecting a roof, it is necessary to take into account the possible maximum wind load that occurs during cataclysms.
Snow load
This is a value that represents the total mass of snow that can remain on the roof until it slides off. This parameter is of great importance in the calculation, since the weight of snow can easily deform it if there are errors in the calculations.
For each area, the reference books contain certain figures for the average amount of snow; the information in the reference books has been collected by specialists for more than ten years and is completely true.
Thermal insulation
Thermal insulation of the roof also affects its condition. This is due to the fact that with poor thermal insulation, the roof warms up and the amount of snow on it gradually decreases. Afterwards, the roof does not warm up and the amount of snow on its surface gradually increases.
If the calculation of the structure was carried out without taking into account thermal insulation, then it will probably not withstand the snow load after insulation; this point should be taken into account.
The shape also influences the choice of a particular angle. So, for single-pitched roofs it is customary to make a slope from 20 0 to 30 0, and for gable roofs from 20 0 to 45 0. This is due to the design features of each type of roof.
It became possible to achieve such a good result by reducing the roughness and using a special surface coating.
The minimum slope of a metal tile roof cannot always be applied. The low slope of a metal tile roof has both positive and negative aspects.
Positive aspects of a small angle of inclination:
- reduced consumption of roofing material;
- reduced weight;
- ease of installation of weirs.
Negative moments of a small angle:
- use of reinforced sheathing;
- high requirements for load capacity due to the likelihood of large amounts of snow accumulation;
- increased requirements for the tightness of all joints due to the small angle of incidence of water during rain;
- lack of possibility of creating attics or large attics.
Positive aspects of a large roof slope:
- The possibility of moisture getting into the joints of the roofing material during rain is almost completely eliminated. This is due to the large drop angle;
- reduced, and at angles from 45 0 practically absent snow load. No need to install a snow retention system;
- the ability to use simple fasteners such as screws and nails;
- the possibility of creating attics and attic spaces.
Negative points of a large slope:
- high consumption of material, both roofing and rafter systems;
- heavy roof weight;
- high wind load due to the large windage of the roof;
- The difficulty of drainage is due to the large area on which water accumulates.
The best option is to use an average roof slope angle, which allows you to get the best performance. Calculating the correct angle always comes down to finding a compromise between the strength of the roof and possible architectural delights.
Metal tiles are one of the most popular roofing materials due to their lightness and ease of installation. The only difficulty that arises for developers is the question of what minimum slope of a metal tile roof is allowed during construction. The optimal angle of inclination is determined at the design stage, taking into account all the factors, which we will discuss below.
What determines the amount of slope
In order to correctly calculate the roof slope, it is necessary to take into account several factors that determine this value:
- snow masses;
- wind;
- roof insulation.
Snow load is the level of snow that will accumulate on your roof without sliding down under the weight of its weight.. It is very important at the design stage to find out what the level of snow precipitation is in a given region in order to make all calculations correctly and prevent possible deformation of the roof under the weight of snow.
Types of pitched roof construction
. Information about the wind strength in the development region, as well as all possible cataclysms for this region, should also be studied in advance.In addition, the minimum angle of inclination of a metal tile roof is influenced by the presence of heating pipes and thermal insulation of both the roof and the house itself. Very often you can come across such a picture when two adjacent houses with the same roof slope have different levels of snow masses on the roof. If you look closely, the house with the least amount of snow necessarily has heating or heating pipes, the heat of which heats it up.
However, if you increase the thermal insulation of the roof, the snow will melt much worse, because the roof will no longer give off heat that melts the snow masses. That is why calculations are made simultaneously with the choice of insulation.
Roof shape and rainfall level
Minimum value The angle of the roof is influenced by many factors, including the shape of the roof and the level of precipitation. The minimum slope of a metal tile roof is only 14 degrees. However, this value is considered suitable only for ideal operating conditions: in a mild warm climate, without precipitation in the form of snow or rain.
If you plan to have a pitched roof structure, the optimal slope of the elements is 30 degrees. If the roof is built with two slopes, it is worth making a slope of 40-45 degrees.
As already indicated, the amount of precipitation has a direct impact on the choice of the minimum angle of inclination of the metal tile roof. For example, if it is less than 22-25 degrees, then sooner or later moisture will begin to fall directly into the roofing joints. In addition, a small slope will not allow snow masses to roll freely from the slope of the roof; they will lie like a dead weight on the roof, compacting and gradually deforming it.
On the other hand, an angle of 25 degrees is ideal for windy, windy areas, because the level of blowing will be minimal.
Heating consumption at different roof angles A small angle of inclination is used extremely rarely in private construction.. The optimal operating conditions for a house with a small roof slope are a warm, mild climate where sunny days predominate, because heating of such roofs occurs mainly from solar energy. Thus, our terrain is not very suitable for such a design.
The angle of inclination practiced in domestic construction is much greater than the minimum, i.e. 14 degrees. The main task is to find the optimal value for a particular roof, so to speak, the golden mean between a good level of resistance to both precipitation and winds.
How to choose the optimal value
The greater the angle of inclination of the structure, the larger its entire area, i.e. the windage of the metal tile roof increases, and the snow will roll straight down without stopping on it.
Snow doesn't roll off the roof
Naturally, the larger the total area of the tile covering, the greater the material consumption. Thus, a roof with a high angle of inclination costs much more.
That is why most developers do not immediately strive to make the greatest slope, but try to find the minimum permissible slope angle, which will allow them to save significantly.
In addition, the overall strength of a roofing structure made of metal tiles can be increased not only by reducing the angle of inclination, but also by using frequent sheathing.
Lathing with a minimum distance between elements will create a kind of shock-absorbing cushion and increase the strength of the internal roof structure.
Lathing strengthens the structure Thus, if your region has the most unfavorable conditions, including a large amount of snow precipitation, then it is better to strengthen the sheathing and make the slope angle larger. Well, if there is little precipitation in the region, but there are very strong gusts of wind, it makes no sense to make a maximum slope, because it will be subject to enormous wind load and may not withstand it. It is best to choose the average value.
Our huge country is located in different climatic zones. If there is strong wind and snow in the Far North and Far East, then in the South of Russia there may be rain and wind. You need a very responsible approach to choosing roofing material and calculating the slope of the roof of your house. The most practical choice is metal tiles because they are inexpensive, durable and beautiful. But the angle of the roof depends on the expected wind load and precipitation typical for your region. So what should be the minimum pitch angles for your metal roof? This question needs to be answered.
In this article
Properties of roofing material
In modern construction, a wide variety of roofing coverings are used, but metal tiles are deservedly considered one of the most popular materials. In many countries, materials such as tiles have long been produced. Therefore, the use of metal not only reduces the final cost of the product, but also serves as a harmonious continuation of ancient traditions. The high technical characteristics of metal tiles include:
- the use of galvanized sheet metal and its coating with durable polymer paints to impart anti-corrosion properties;
- wide choice of color architectural solutions;
- manufacturability and ease of installation of the roof, which does not require the use of special tools and devices;
- the lightness of the material, allowing it to be installed at high altitudes and in complex rafter structures;
- no heavy load on the rafters due to the low weight of the sheet;
- with a relatively thin sheet, it can withstand quite large loads, since it has stiffening ribs.
All of the listed properties allow the use of this coating in difficult climatic conditions. To calculate the amount of material, you need to know the minimum angle of inclination of a metal roof.
How to determine the roof pitch in your area
To calculate the strength of the roof structure and the amount of material required, you need to know the optimal roof slope.
- It is necessary to take into account a number of circumstances, including:
- projected number of slopes;
- used under-roof space;
- Efficiency indicators;
weight of the structure.
It would seem that the steeper the slope, the better, but this leads to increased material consumption and increased weight, as well as to a large wind load on the structure. Therefore, there is such a thing as the optimal angle of inclination of a metal tile roof.
Steep slopes, ranging from 30 to 45 degrees, are more suitable for regions with lower temperatures and frequent snowfalls, but the increasing wind load on the roof and the building as a whole must be taken into account. It is also important to take into account the strength characteristics of metal tiles, which are laid down by the manufacturer of the material. In the case of steep slopes, it is necessary to fasten the sheets more often than usual, because they are prone to sliding under the influence of gravity. The greater the angle of inclination of the roof, the more labor-intensive and less economical it will be to install.
There are two loads on the roofing material, which, in terms of technical strength, oppose each other.
The steeper the roof slopes are constructed, the greater the angle of inclination, the easier it is for precipitation to mix on them without lingering on the surfaces of the slopes. But at the same time, the roof area increases, threatening an increase in wind loads. Therefore, it is worth choosing the optimal option based on two parameters, taking into account the factor of increasing the cost of the structure due to increasing the size of the roof structure.
What is the optimal roof slope angle recommended by the manufacturers of this building material? After the tests, companies producing metal tiles recommend using it when the slope is inclined from 11 to 45 degrees. In this case, the most acceptable angle of inclination is from 12 to 22 degrees. Building codes and regulations do not give clearly defined recommendations on this matter, but the preferred one, with a slope length of about 6 meters, is an inclination angle of 14 degrees. We have come to the choice of the most economical method of covering the roof, which is determined by such a concept as the minimum slope of a metal roof.
What is the minimum slope and how to determine it
Depending on the climate zone, architectural design and aesthetic preferences of the home owners, the following types of roofs are erected:
- multi-gable roof with a complex and slender structure;
- vaulted roof as an element of national culture in architecture;
- hip roof, complex hipped structure;
- hip roof, combination of isosceles triangles;
- gable roof, widespread and time-tested;
- the roof is pitched, used mainly for technical and utility rooms or as an element of a more complex structure.
Multi-gable and vaulted roofs are not suitable for the use of metal tiles, which are used only in the elements of these structures. While hip roofs are quite widely used in the middle zone and are characterized by a choice of minimum slope angles ranging from 22 to 45 degrees. Hip roofing is used as a decorative element, and the angle of inclination of the isosceles triangles is directly dependent on the area covered by the tent. This structural element is very economical to manufacture, and the angle of inclination ranges from 35 to 45 degrees.
One of the most popular roofs is gable. The manufacturer recommends maintaining minimum roof slope angles ranging from 12 to 14 degrees. Given the harsh climate, it can be recommended to expand these limits from 14 to 22 degrees of slope. It is with these characteristics that the roof resists possible strong winds well, and also represents an almost monolithic structure that prevents moisture from penetrating into the under-roof space of the building.
For single-pitch roofs, the minimum slope angles range from 11 to 14 degrees, since large slope angles create a danger of the roof falling off in multidirectional gusts of wind. In the climatic conditions of Russia, you need to adhere to the minimum slope of the slopes from 14 to 22 degrees. When building in flat or mountainous areas, it is necessary to take into account the landscape and wind rose, depending on the time of year.
When choosing the type of roof, each person’s taste preferences play a decisive role. Everyone wants to build a house so that it is beautiful, comfortable and lasts for many years. The roof crowns the building and receives special attention because it not only decorates, but also protects from the effects of an aggressive environment. In order for it to serve for many years, it needs to be properly designed and built correctly. And to save money, you need to choose the correct slope of this roof for metal tiles, taking into account the climatic conditions of your region.
The determination of the roof slope is largely influenced by the type of roofing material and climatic conditions. The functionality and reliability of the roofing have a strong impact on the performance properties of the structure. That is why a competent calculation of the roof slope relates not only to aesthetics, but also to the practical components of a modern roof.
Criteria for choosing a roof slope
To determine the optimal roof slope, several factors must be taken into account. Climatic conditions and wind strength, as well as financial capabilities, allow us to calculate the minimum roof slope. Any increase in these values can significantly affect many indicators.
A greater slope allows rainwater to flow down much faster and not seep through minimal roofing defects inside. The snow mass leaves steep roofs more easily, and with a roof slope of more than forty percent, the snow load will be minimal.
However, it should be taken into account that such positive aspects are offset by an increase in the consumption of building materials and can negatively affect the volume of drainage, which contributes to the difficulty of drainage.
The main factors that must be taken into account when calculating the roof slope angle are:
relate:
- type of rafter system;
- roofing material;
- climate features;
- roof configuration;
- purpose of the building;
- features of the design and appearance of the building;
- purpose of the attic space.
The purpose of the attic is especially important to consider for two-or. If the attic is not planned to be used as a living space, then it is not advisable to significantly raise the ridge part and increase the roof slope. If you want to equip a residential attic space, it is recommended to make the roof slope as significant as possible.
The optimal roof slope is carried out in accordance with building codes. Such standards specify the minimum roof slope values in accordance with the type of roofing materials and taking into account all parameters of snow and wind loads.
Requirements in the snip when installing metal tiles
The entire scope of roofing work is carried out in accordance with the recommendations of SNiP, which regulate acceptance taking into account the roof slope, regardless of the roof configuration.
Tilt angle
The slope is the angle between the slab plane and. The angle of the roof slope affects the installation work on the roof. A small angle requires additional waterproofing using silicone sealant, which helps prevent moisture from entering the fasteners and joints.
In addition, the overlap also has a significant impact. Thus, changing the roof slope also changes the overall consumption of metal tiles.
Calculation of the angle of inclination
To correctly calculate the angle of the roof slope, you should apply the simplest mathematical formulas, taking into account the height of the ridge, the length of the span and the rafters. The calculation is based on the height of the ridge and the dimensions of the roof space:
- residential attic space;
- unused attic space;
- used attic space;
- ventilated type of space.
The calculation of the angle is based on the absence of the possibility of precipitation accumulating on the roof surface. As a rule, this angle is at least three degrees.
Most often, the formula Y = H: (1/2*L) is used to calculate the slope, where
- Y – the desired slope value;
- H – indicator of the height of the ridge above the ceiling;
- L – indicator of the width of the structure.
It should be taken into account that when calculating the slope of a sloping roof, the value can vary within the slope and the value L is taken to be the width distance that is covered by a given roofing section. It is allowed to use special table values to calculate the roof slope.
If you plan to install a residential building, then for calculations you should:
- divide the width of the pediment by two (we get the value A);
- we find the height of the roof, which most often has a value of 180 centimeters and obtain the value B;
- substitute the obtained values into the formula sine Y=A/B;
- We use the Bradis table, according to which we round the found value up. The resulting result will be the roof slope angle.
Minimum permissible slope
In accordance with building codes, the values of the minimum roof slope values for different types of roofing materials have been obtained, which take into account permissible snow and wind loads:
- slate and natural tiles – 20°;
- profiled sheet – 12 °;
- rolled roofing materials - the minimum roof slope is inversely proportional to the number of layers of roofing;
- – 6 °;
- – 14°.
Positive Features:
- raindrops flow faster along the roof at a large angle and do not fall between the roofing elements and under the overhang;
- a large slope reduces the snow load, which eliminates the need to install snow retention systems;
- the main level of force load on roofing sheets “shifts” in the direction of the slope, which allows the use of standard fasteners in the form of nails and self-tapping screws;
- It is allowed to create residential and non-residential under-roof premises with the correct geometry and significant footage.
Negative Features:
- the consumption of roofing materials increases significantly, and an increase in the roof slope by thirty degrees leads to an increase in the area under coverage by almost twenty-five percent;
- the weight of the roof increases as a result of the increased mass of the roof covering and supporting structures;
- the formation of a significant degree of windage and an increase in wind load;
- problems in organizing drainage in the form of the need to install multi-tier drainage systems.
The optimal angle of roof slopes is a value that entirely depends on climatic conditions, the type of roofing material chosen for installation, as well as the financial capabilities and preferences of the homeowner.
Let's sum it up
The installation of a metal tile roofing requires the use of a minimum angle of inclination, which helps ensure the stability of the roof against significant wind and snow loads.
An incorrectly calculated roof slope angle can provoke the formation of so-called “blowing” of the roof, which can cause a significant excess load on the rafter system and will inevitably lead to destruction.
If metal tiles are chosen as a roofing material, then it should be taken into account that for this relatively new material there are no clear SNiP requirements and you must follow the manufacturer’s instructions.
Most often, manufacturers of metal roofing tiles indicate from ten to fifteen degrees as permissible roof slope values.
An increase in roof slope necessitates the creation of additional reinforcing structures, and a decrease entails additional costs for waterproofing materials.
The durability and quality of the roof directly depends on the correct selection of covering material. Not least important selection criteria are appearance and compliance with environmental standards. Among experts, the opinion has long been strengthened that they fully meet these requirements.
Of the three types of metal roofing material, the profiled sheet covering stands out favorably imitating natural tiles - metal tiles.
Its base is rolled steel, coated with an aluminum-zinc composition to resist harmful environmental influences. For increased stability, add an additional finishing layer to the metal polymer coating applied. In this article you will learn how to calculate the roof angle for metal tiles and what factors affect the roof covering.
Affordable price and improved performance characteristics allow metal tiles to occupy a leading position in the roofing materials sales market.
The positive aspects of its use are:
- a light weight - about 5 kg/m2, as a result, there is no need to build a complex one;
- does not require special installation skills;
- wear resistance;
- long service life;
- elegant and festive look, suitable for any design development.
Among the shortcomings, users and experts most often note:
- increased noisiness during rain or hail;
- need for use due to avalanche-like snowfall;
- a large number of fastening elements that are directly exposed to precipitation;
- A grounding device is required to protect against the build-up of static electricity.
NOTE!
Please note that there is a type of metal tile with additional protective layer as a topping made of natural stone chips. Unlike classic spraying, this composite coating gives a solid appearance and protects the house well from noise penetration.
Roofing sheet composition
Qualitative indicators metal tile roofing in many ways depends on:
- the required minimum steel sheet thickness – not less than 0.4 mm. With a small slope, a coating with a thickness of less than 0.4 mm may not withstand the snow load. Increasing the slope, to reduce this impact factor, increases the possibility of increased wind load, which also negatively affects metal thinner than the specified value;
- emerging corrosion from possible damage during transportation or unprofessional work using a grinder when cutting sheets. Important in cases where it is impossible to do without using a grinder, treat the cutting area with a protective compound ;
- mandatory presence of an anti-condensation screen made of . Need to know that a superdiffusion protective membrane cannot be used as such an anti-condensation material, since its use implies more frequent and prolonged exposure to moisture on the inner surface of the sheet.
What factors affect the roof?
Basic factors negatively affecting condition and durability metal tiles are divided into three types:
Short-term
- the weight of people and building materials during the installation and maintenance of the roof;
- standard snow loads;
- temperature climatic influences;
- wind loads.
Long-term
- snow loads below the established norm;
- impact due to deformation of the supporting base.
Special
- seismic impacts;
All components in the construction of the rafter system are guaranteed to ensure the resistance of the metal tile covering to the maximum permissible overloads.
Sheets of profiled metal have sufficient rigidity, so they are not required. But when installing a rafter system, it is necessary to correctly calculate the pitch and angle of inclination of the rafter leg.
Roof angle for metal tiles
Minimum angle metal roof slope is 10 degrees.
Permissible slope metal tile roof can be values ranging from 10 o to 90 o.
When choosing the optimal slope, you need to take into account that if the slope is too small, it will be difficult to use the attic space.
In the case of a large building height, it may be difficult to access the roof to carry out technical activities. An increase in the angle of inclination results in an increase in surface area, which will negatively affect the final cost of materials and work performed.
Correct calculation tilt angle parameters impossible without taking into account such components:
- which model of corrugated metal tile surface will be chosen for use. The characteristics of some manufacturers initially include data on the minimum permissible slope;
- what kind of design is meant - single-slope or double-slope;
- possibility of snow removal after .
Taking these conditions into account, without having additional input in the form of a special climatic zone, we can take as a basis the optimal slope with a slope length of about 6 m. is 22 degrees.
This figure is not found in technical documents on roof construction; it was obtained experimentally as a result of observations of the metal-tiled surface in use.
How to choose a roof angle for metal tiles?
How to correctly calculate the optimal slope?
To accurately calculate the angle of inclination it is necessary know two sizes:
- height of the truss structure, in other words, the vertical distance from the top of the parapet on which the rafter leg rests, ;
- the width of the house itself.
For a pitched roof, the slope will be the value obtained by dividing the height of the structure by the width of the house. In the case of calculating a gable roof, the height is taken and divided by half the width of the house. Since it is customary to express slopes as a percentage, the resulting figure is multiplied by 100.
To obtain a more accurate result, use not the floor slab as a reference point for the distance to the ridge, as many people mistakenly believe, namely parapet top, as bases for supporting rafters.
In practice, there are options for installing roofs; the minimum slope for metal tiles is less than 10 degrees. Such exceptions apply special recommendations for construction.
The pitch of metal tiles depending on the angle of inclination of the roof
In view of the increased snow load, a reinforced structure of the rafter system with a device is made continuous sheathing. If all standards are observed, a waterproofing carpet is laid on it. When laying sheets under transverse and longitudinal joints, special gaskets are installed.
Useful video
We invite you to watch a video tutorial on how to measure the roof angle yourself: