What is the minimum roof angle? Roof slope

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

Peculiarities

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

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

The theory of calculations may also be of interest to the home owner. For example, such knowledge makes it possible to check whether the professionals used the correct methodology. They also help to correctly present your original ideas. In addition, the calculated parameters allow us to determine required quantity building materials and for rafter system, and for roofing.

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

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

• one horizontal plane;
• one plane of the roof slope.

This parameter is measured from the top edge to the base of the rafter system. When calculating, only sharp corners, since there are no obtuse slopes by definition. Steep slopes are rare. Typically, they are used for decorative design(for example, when they build turrets in the Gothic style).

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

To get a better idea of ​​what it should look like, you can take a protractor and look at the degree divisions.

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

Kinds

Experts distinguish several main types of roofs.

• Single pitch roof. In this case, the roof looks like a flat plane. She has distinctive parameters in height.

• Gable roof. It is a reliable, easy-to-install option. The roof includes two slopes connected at right angles.

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

• Vaulted roof type. It is rare because it involves a limited selection of materials. Such options are built only from brick or stone. The rarity of choosing such roofs is also due to their heaviness. In small private construction this type is practically not used.

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

Experts also highlight types of roofing that can subsequently be used., and options that are not subject to exploitation. If professionals classify a roof as a non-exploitable type, this means that there is practically no space between the roof itself and the upper ceiling. This territory can be used, but only as a technical one. For example, this is the case with a low-slope pitched roof.

Shed roofs are the most beneficial for construction. They require minimal costs for materials, and the work can be done independently. If the roof has a slight slope, then on its surface you can create a resting place without constructing a complex attic.

The space under the roof can be used if the roof type is pitched. The attic area can be used for household needs. It can also expand your living space.

The choice of one type of roof or another is associated with many nuances. One of the main ones is the climate factor.

Climate influence

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

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

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

To eliminate the risk of breaking the roofing material, a strong rafter system is installed, since a large weight will affect the entire structure.

It is worth remembering that the greater the inclined angle of the roof, the more money will have to be spent on construction. Costs are also associated with the choice of roof covering option (not all materials can be installed on high pitched roofs).

For different materials

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

Slate covering or tiles can be laid on a roof with a minimum slope of 22 degrees. On roofs with a lower slope, moisture will accumulate and seep in at the joints of the parts. If the roof has slopes with a lower degree, you can use roofing felt and other bituminous materials, which are mounted in one piece.

Manufacturers of profiled sheets claim that this material can be laid at a minimum permissible angle of 12 degrees. Moreover, if the slope angle is minimal, then the joints between the sheets must be sealed with sealant.

For metal tiles The minimum possible slope of the slope is 14 degrees. At the same time, there are rules for arranging floors. For example, if the angle is more than 45 degrees, then the installation location of the ridge board changes. The method of mounting the ridge itself also changes. For small values, an aeroroller is attached between the ridge strip and the tile. It prevents snow from penetrating under the roof.

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

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

When choosing a particular covering material, you should take into account not only the characteristics of the slopes, but also the strength values ​​of the roof. Structures must support not only their own weight, but also the weight of the roofing material. In addition, all roofing system must successfully withstand external loads.

The slope of the slopes is often associated not only with the choice of materials, but also with the choice of the type of sheathing. If the angle of the slope is small, then a continuous sheathing is installed. Also, when installing a flat roof, it is necessary to install a drainage system. There are regulatory parameters for any roofing options. They should be kept in mind even if the simplest flat option is chosen.

Standard values

Installing a flat roof is a simple undertaking. The main thing is to use the right material High Quality. The slope of a flat roof is also important.

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

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

Today you can find special slabs on sale that have high thermal insulation qualities. Such plates have a wedge shape. It is enough to lay the material on a flat surface. The result is a slope corresponding to regulatory indicators. The only drawback of the material is its fairly high cost.

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

When creating a ramp, it is worth considering the roof area. For a garage roof, for example, it is worth considering one slope, which will be directed into the drainage funnel. Slope for standard house size 80 sq. m will be 2-4 slopes. In this case, all of them must be sent to drainage system in order to freely deliver water to it.

How to calculate?

If there are usually no difficulties with the installation of a flat roof, then engineering calculations are required to install a roof with several slopes. The easiest way is to calculate and determine the values ​​in degrees. For example, to arrange a roof with a slope of 30 degrees, you can use a mathematical method.

This will require two measurements.

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

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

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

Experts do not always use a conversion table in their measurements. The coefficient in percentage can be used equally with the coefficient in degrees. In general, professionals use special tools in calculations. For example, you can measure the area parameter using a special inclinometer.

The tool is a ruler with a rack. One axis contains the usual scale in centimeters, the other - a pendulum. If the rack with divisions lies horizontally, then the pendulum will show zero. When measuring the slope, the rod is installed perpendicular to the ridge. In this case, the scale shows the result for a specific value immediately in degrees.

Currently on the market you can find the most different instruments, which can be used to measure slopes. Levels can be either drip-type devices or electronic devices. In this regard, the mathematical measurement method cannot be considered relevant. Modern devices allow for more accurate calculations.

All over the globe there are thousands and thousands of architectural traditions in terms of appearance roofs But modern architects have completely changed the idea of ​​culture suburban construction, introducing pitched roof forms as ideally combined with landscape design and diverse in execution. Of course, this new fashionable tone was set by the residents of Australia, where the absence of snow at all is like natural phenomenon allows them to create whatever their imagination dictates with the architecture of residential buildings.

But in the snowy regions of Russia such a roof can be built, but with the appropriate slope and in the right direction. In a word, main parameter functionality - the angle of inclination of a pitched roof, which we will now teach you how to calculate.

Step 1. Calculate permanent and dynamic loads

First of all, calculate the loads on a pitched roof. They are usually divided into constant and dynamic. The first is the weight of the roofing covering, which is always located on the roof, installations such as antennas and dishes, a chimney, etc. Those. everything that will be on the roof both day and night.

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

Snow loads

So, if you make a pitched roof slope of 30°, in winter the snow will press on it with a force of 50 kg per square meter. Just imagine having one person per meter sitting on your roof! This is the load.

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

The minimum angle that must be so that snow can slide off a pitched roof on its own is 10°. And the maximum is 60°, because there is no point in making the roof steeper. The same applies to snow, which clings even more to such a roof.

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

Wind loads

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

Combined loads

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

What if you and a friend have to climb out onto the roof during a heavy storm and snowfall? Is the design designed to withstand snow, wind, and the legs of at least two people at the same time? This is how trouble happens.

Step 2. Select the roof slope

The slope of a pitched roof is in a fairly wide range: from 6° to 60°. It all depends on the area in which you are planning to build: if you need to successfully dump tons of snow every winter, then make the slope steeper; if you plan to protect yourself from the wind, then make it flatter. And also from many other factors, including aesthetic ones.

Steep pitched roofs

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

Low-slope pitched roofs

The speed of flowing rain and melt water on low-slope slopes is much lower, and therefore there is a risk of water stagnation, dirt collecting and ice getting stuck. On such roofs, moss quickly develops and leaves stick to it. Especially if the roof covering is rough.

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

But, if such a building rises big roof at home, then it’s okay:

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

Therefore, the lower the angle of inclination of such a roof, the more you need to take care of its waterproofing so that melt and rain water cannot penetrate into the rafter system. Therefore, roofing coverings such as membranes, roll insulation or solid sheets are already needed here.

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

Minimum pitched roof angle

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

Moreover, at a certain angle pitched roof directs the air flow in the desired direction, capturing precipitation and removing it. Remember this!

Step 3. Determine the slope requirements

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

Ventilated design

These are installed in buildings closed type. Ventilation is provided by vents and special voids between the insulating layers, through which air passes, capturing droplets of moisture from the insulation and carrying them outside.

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

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

Non-ventilated design

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

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

Combined design

Such roofs combine the design of both previous types. Here required slope The roof is given due to thermal insulation. It turns out to be economical, but in winter you will have to constantly clear off the snow.

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

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

Step 4. Calculate the exact angle of the slope

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

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

There is another interesting point: many architects specifically calculate the angle of a pitched roof so that it is equal to angle the elevation of the sun in a given area in mid-spring. Then you can calculate down to the millimeter when and what kind of shadow there will be, which is important for planning terraces in front of the house and other recreation areas.

Step 5. Limiting the choice of roofing covering

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

• Profiled sheeting: min 8° - max 20°.
• Seam roofing: min 18° - max 30°.
• Slate: min 20°- max 50°.
• Soft roof: min 5° - max 20°.
• Metal tiles: min 30° – max 35°.

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

You will be surprised, but today, especially for low-slope roofs, the same types of roofing coverings are being developed that are usually used with a slope of at least 30°. For what? This is the fashion in Germany, which has reached us: the pitched roof is almost flat, and the roof is stylish. But how? It’s just that manufacturers are improving the quality of locks, making the overlap area larger and thinking more carefully about protection from dirt. That's all the tricks.

Step 6. Deciding on the rafter system

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

Hanging rafters

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

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

Or like in this project:

Layered rafters

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

Sliding rafters

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

The point is simple: the more nodes there are in the rafter system, the more flexible and durable it is. The more a pitched roof can withstand the pressure of the weight of the roofing and snow without breaking. But there are rafter systems where the connection is generally static:

Step 7. Calculate the height of the pitched roof

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

Method number 1. Geometric

A pitched roof has the shape of a right triangle. The length of the rafter leg in this triangle is the hypotenuse. And, as you remember from your school geometry course, the length of the hypotenuse is equal to the root of the sum of the squares of the legs.

Method number 2. Trigometric

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

1. Let us denote by A the length of the rafter beams.
2. Let us denote by B the length of the rafters from the wall to the ridge, or the length of part of the wall in this area (if the walls of your building are of different heights).
3. Let X denote the length of the rafters from the ridge to the edge of the opposite wall.

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

X = A / sin Y

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

Method No. 3. Online calculators

Have you figured it out? Now let's move on to the construction of the roof itself:

We hope you figured it out easily!

It has a number of advantages, such as: its installation will require less materials, ease and simplicity of installation and additional usable territory.

Many people do not associate the phrase flat roof with a slope. Although this is far from true. Even the smoothest roof has its own slope, even if it is minimal.

At a minimum, this is necessary so that melt water and water after rain can easily flow into the installed funnels, which are part of the internal drainage system, or into the gutter of the external system.

In addition, on such a roof it is easy and simple to install additional, necessary equipment. To date, There are several types of flat roofs:

• Operated roof;
• Unused roof;
• Traditional roofs;
• Inversion roofs.

The slope that should be on this type of roof is is approximately 1-5 degrees, if you neglect this, then water, both rain and melt, will accumulate, which in turn will damage the roof.

In summer, you may not encounter such a problem, since rainwater dries out under the rays of the sun. In winter and autumn, such water can freeze at night and melt during the day.

Puddles form, which ultimately leads to moisture gradually penetrates into the insulation. The essence of the mechanism is that moisture penetrates into the layer, which means that inevitable leaks occur.

But this is not the only problem. In addition, puddles on the roof can contain dust, which eventually settles to the bottom. Seeds of various herbs and plants can fall into this puddle and germinate there.

Often on the streets you can find houses with grass or thin trees on their roofs. It is logical that this spoils the roof and also spoils the aesthetic appearance of the entire building.

To avoid such a nuisance, and thereby extend the life of your roof, it is necessary to carry out the roof tilting procedure. Such complex manipulation is carried out at the time of construction itself.

The process itself is quite complex and includes many different structured activities. The purpose of this procedure is to ensure that the roof itself acquires the required slope.

But before you start pitching the roof, you need to find out what a flat roof consists of.

Flat roof

In essence, it is a cake made of several layers:

• Direct basis, which represents reinforced concrete slabs, which have a certain wave height;
• , which can be made from different materials, such as bitumen, or rolled materials;
• Next layer -, which can be made of mineral wool or other durable material.

The components of such a pie can be changed if the builder wants to make the entire roof using new building materials. It is worth understanding that such a procedure as slope, carried out immediately at the time of laying the insulation.

It is important that in addition to these main layers of the roof, there must also be water intake funnels or gutters.

The angle of the roof slope is very important, and it depends on many parameters. The first thing you should pay attention to is the wind exposure. If you live in an area where there are frequent strong winds, then it is worth making a small angle of inclination.

CAREFULLY!

If you make a strong slope of a flat roof, then the wind can tear out roofing sheets. It is important to note that the angle of the roof dictates the necessary conditions for the rafter system, as well as for all components of the roof, namely: rafters, sheathing pitch.

Obviously, the steeper the slope of the roof itself, the faster the outflow of water.

Slope in percent

Minimum angle and calculation of roof slope

The minimum slope angle can be determined based on the materials of the roof itself:

• If the roof is made of , then her minimum slope must be at least 12 degrees(according to SNiP). If the roof is made of, the angle increases to 15 degrees. It is important to understand that the cracks in the material and other joints must be treated with a special sealant - frost-resistant/water-resistant. If the angle of inclination is 15 degrees, then the sheets of material should be overlapped by about 200mm, if the angle is smaller, then the overlap should increase;
• The minimum slope angle may be in cases where if the roof of your house is made of artificial materials. These, in turn, include membrane coatings and bitumen-based materials. It is logical that by the magnitude of the slope angle, The number of layers of the roof also affects. If, for example, the roofing is carried out in two layers. then a tilt angle of 15 degrees is quite sufficient;
• Having covered the roof, it is worth understanding that 11 degrees of inclination angle is quite enough, but in this case you need to make a continuous type of sheathing.

Such a process as the slope of a flat roof, made from such materials:

• Extruded polystyrene (technoNIKOL);
• Wool, both mineral and glass/basalt based;
• Polyurethane foam;
• Foam concrete;
• Foam glass;
• Various types of backfill materials.

Each of the materials has its pros and cons. And before you start work, it is worth correctly calculating the angle of inclination. In fact, this calculation is quite easy to carry out; for this you need to use a protractor, or use fairly simple mathematical formulas.

Despite the fact that a flat roof is called flat, it still needs a slope. The minimum slope for a flat roof is 1 degree or 1.7%.

In the instructions for using bitumen and polymer coatings for deviation it is indicated that optimal angle the tilt should be 1.5 degrees. A tilt of 1-2 degrees is acceptable.

Everything is very simple here. You need to know the height of the roof and its width. Next, simple trigonometric formulas will help calculate the immediate angle (sine, cosine, tangent). And from the existing table, which was calculated earlier, you can find out the value as a percentage.

There is another way to calculate - the value of the roof height must be divided by half the width, and the result already obtained must be multiplied by one hundred, after which, in the table, you can find out the percentage value of the future inclination angle. This option is faster, but in terms of accuracy they are both correct.

Minimum slope

Sloping a flat roof using bulk materials

If you decide that the tilting procedure will be carried out using bulk materials, then the first thing worth noting is the scheme according to which it is necessary to carry out such a procedure:

1. First of all, on its own concrete base, it is necessary to lay a layer of glass insulation. This material not only has a long service life (30-35 years), but also has high waterproofing performance;
2. Further, it is necessary to pour the main material on it - expanded clay. But at the same time, everyone needs to create the right bias;
3. Necessarily you need to cover a layer of expanded clay with a special plastic film . It is important to note that it must be overlapped;
4. Further, it is necessary to apply the prepared sand-cement screed , doing it smoothly, slowly. Its essence is to level the layer of expanded expanded clay;
5. After these events you can begin shape the roofing “pie”, according to the developed .

Remember that when laying each layer, you need to ensure that the previously prepared angle of inclination is maintained.

ATTENTION!

If you are worried that the expanded clay will move when you start laying sand-cement screed on top of it, you can fill it with cement laitance. But it is worth understanding that because of it, the structure becomes heavier.

If you want to create minimum angle slope, and the roof area is not particularly large, then sand-cement mortar will be enough.

Bulk material

Thermal insulation materials

Another good material for roof pitching is thermal insulation materials. Experts say that this is the most affordable option.

Its advantage is that it is quite light and quite cheap, which is very important in construction important role. Mineral wool, the most best material. The process diagram is quite simple.

It is necessary to attach the material to the base itself, using self-tapping screws or dowels. Some prefer sheets of such cotton wool to be glued to a previously cleaned base, special glue. This process can be performed both during and during roof installation.

Thermal insulation material

Foam concrete

A good material that can be used to slope a flat roof is foam concrete. It is immediately worth noting that this procedure must be carried out using special equipment.

A layer of foam concrete is poured onto the base itself, but at the same time the angle of inclination is noted, and only after make a special screed from foam fiber concrete. Next, it is important to apply waterproofing material.

A huge advantage of this tilt option is high thermal insulation rate, as well as other mechanical characteristics . For example, strength and durability.

Speaking of minuses, there are some here too, or rather one. This is the price. She's tall enough. And again, it will not be possible to carry out such a procedure on your own. Therefore, in this case it is worth turning to professionals.

• If the roof has minimum slope, then it is important to note that in this case, needs to be installed correct systems drain. The slope itself is done exclusively to the side (funnel, gutter);
• If your roof is bitumen, you should make the slope angle less than 6 degrees, while The bottom layer of waterproofing must be made of membrane materials;
• It is important to know that with small slope angles, it is necessary to ventilate the under-roof space itself, what does all the stingrays have to do with it. The thickness of the gap also depends on the value of the angle (the larger the angle, the smaller the thickness and vice versa).
In contact with

• Choosing a roof slope only based on your aesthetic preferences would be somewhat reckless. Since the reliability and strength of the future structure largely depend on the correctly calculated value of the angle of inclination, taking into account climatic features terrain. That is, the roof slope should be optimal from both a practical and aesthetic point of view.

  The fact that ideally “flat” roofs simply cannot be beyond doubt. After all, rainwater must somehow be drained from it. Therefore, a slope is made on them in order to obtain at least the minimum slope of a flat roof.

  It ensures the most efficient collection of rainwater from the surface of the roof covering and directs it either to the parapet or to the internal drains.

  minimum roof angle

  The minimum roof slope depends on many parameters, including the material waterproofing coating, the type of roof itself (standard or inverted), the number of waterproofing layers, and more.

  Basic requirements that determine the slope of a flat roof: SNIP

  What will be the minimum roof slope, depending on various factors, is dictated by special building regulations and norms.

  The dependence of the roof slope angle on waterproofing is regulated by clause 4.3 of SP 17.13330 for 2011, according to which the slope of a flat roof varies in the range of 1.5–10%. Large angles (up to 24%) are performed extremely rarely, since the choice of material for waterproofing that would not slide to the base of the sloping roof when the temperature rises is very difficult.

  On a note

  The smallest slope for a flat roof is 1.5% or 1°.

  As a rule, a roof with a low slope has quite large area surface and achieving its ideal value is very problematic. There will likely be areas where water will stagnate, which can cause wear on the roofing material or leaks. You can perform the slope geometry relatively accurately using a screed. It is also possible to use polystyrene concrete or foam concrete filling. To increase strength, a layer is already placed on top of the laid layer. thin layer durable concrete screed.

  In turn, there is specific connection between steepness roofing structure and the number of layers of waterproofing. The larger it is, the water naturally leaves faster, which means that fewer waterproofing layers will be required (clause 5.5).

  The inclination can be easily checked using a bucket of water. Water is poured onto the selected area; if the water flows almost completely to the funnel, then the slope is flat roof sufficient. A similar check can be carried out on the entire roof surface.

  At the design stage, it is determined by calculation how many water intake funnels are required for a given roof, and already during construction, with the help of slopes, it is necessary to ensure unhindered outflow of water into the funnel from any point on the roof.

  How to calculate the roof slope: which method is better

  As you know, in addition to flat (sloping) structures, there are also pitched and high ones, and there are even more materials for roofing. In order to correctly navigate this diversity, according to SNiP, special tables and diagrams have been developed that reflect the relationship between the steepness of the slope and the type of roof.

  The roof slope is determined by the following parameters:

  • the type and amount of material intended for roofing;
  • necessary protection from wind and moisture;
  • ridge height for repairing an existing roof.

  How to calculate the angle of inclination in degrees and percentages

  Calculator for calculating roof slope

  

  Using this calculator is extremely simple. In fact, any roof can be divided into ordinary gable roofs, the calculation of which is based on a triangle. It is on this position that the work of the calculator is based. The following parameters are used:

  • H – the height of the ridge, that is, the leg of a right triangle;
  • W – second leg, equal to half base width;
  • L is the length of the rafters, also known as the hypotenuse.

  By substituting two known parameters, you can almost immediately determine the slope angle of a roof with similar characteristics. By the way, the third parameter is calculated automatically. The calculator software uses the properties of an isosceles triangle and simple trigonometric formulas.

  Using a protractor

  

  This device, which is also called an inclinometer, has a simple design: several slats with marked divisions and a pendulum. When making calculations, the main rail is placed perpendicular to the ridge. The pendulum pointer indicates the required angle on the division scale. As you can see, nothing complicated.

  Formula for calculating roof slope

  

  And finally, the required steepness of the slope can be calculated by yourself without using slope measuring instruments, mathematically. To do this you will need to know the value

  • vertical height (H), measured from the highest point of the slope, usually the ridge, to the lowest point - the cornice;
  • laying - the horizontal distance from the bottom to the projection of the top point of the slope.

  The angle of inclination of the roof is calculated in degrees or percentages and indicated in the drawing by the letter “i”.

  Mathematically, the percentage of roof slope is calculated as follows.

  i = H: L, i.e. the roof slope angle is found from the ratio of the roof height to the pitch.

  Then, to obtain the desired value as a percentage, the value of the resulting ratio is multiplied by 100. A special table of ratios helps express the slope value in degrees.