Roof pitch calculator online. Why measure the slope of the coating and on what factors does this value depend

Many owners of suburban real estate say that the roof own house should be not only reliable, but also beautiful. Achieve maximum functionality and beauty appearance of the considered structure, it is possible to correct selection materials, as well as the calculation required slope. In our article we will describe how to calculate the angle of the roof. To do this, it is necessary to have data on wind and snow load, construction site and pavement properties.

Before determining the angle of the roof in degrees, you need to find out for what purposes the attic will be used. If this part of the house is a residential slope, it should be maximized, which will increase the height of the ceilings and make the rooms more spacious. The second way out of this situation will be the device of a broken line mansard roof. In most cases, a similar design is made gable, but some may have four slopes. Here you need to carefully calculate everything, because with an increase in the height of the ridge, the useful volume of the attic increases. At the same time, the area of ​​coverage and financial investments in the installation of the roof increase.

• With an increase in the height of the ridge, financial investments in the materials used for coating increase;
• Slopes with a large area are more affected by the wind. If we take two buildings with the same overall dimensions, but having a different angle of inclination in degrees (for example, 11 and 45), then the load from wind flows of the same strength on the second house will be almost 5 times higher.
• If you do not know how to find the angle of inclination, take it large from 60 degrees. On such roofs, precipitation and snow do not linger.
• Not every roofing product can be used on large slopes. The angle of inclination refers to the ratio of the height of the slope to half the width of the house.

Roofs with a small slope angle have a reduced area compared to steep roofs, they are much cheaper, but certain nuances must also be taken into account when installing such a coating:

• The device of special snow retainers to prevent avalanches. One of the options for removing snow masses is a special heating device to accelerate the melting of snow.
• With minor differences in the heights of the coating, there is a high probability of moisture penetrating into the roof structure through the joints. To prevent the roof from leaking, it is necessary to use reinforced waterproofing.

As you can see, designs with a slight slope have more disadvantages than positive qualities. In this regard, every builder must know how to determine the angle of the roof in degrees.

How the amount of slope depends on the material used

The roof of a country house or master's building may have low or steep slopes. During the design of this structure, it is necessary to calculate the cross section of the rafters and the distance between them. How to determine the angle of inclination for different roofing materials, many are trying to understand, but these values ​​\u200b\u200bare already calculated.

During the installation of rolled waterproofing materials, when the roofing material is laid in two layers, the slope of the coating should not exceed 15 degrees. Many would like to know how to determine the angle of the roof in degrees if it is covered with three layers shingles. In this case, the described indicator can vary from 2 to 5 degrees.

pay attention to the following nuances devices:

• The built-up roofing material is recommended for use with a slope of up to 25˚ in two layers, from 0 to 10˚ - in three layers. If there is a roof with a slope of 10 ... 25 degrees, one layer of rolled materials can be laid, but the front surface of such a coating must have a special protective layer.
• Asbestos-cement sheets are used on roofs with a slope of up to 26˚.
• The minimum slope for natural tiles is 33 degrees;
• Profiled sheet or metal tile - 29 degrees or more.

The consumption of roofing products also depends on the parameter under consideration. so designs with slight slopes are much cheaper than analogues with an angle of more than 45 degrees.

What affects slope?

All roofs used may have different shape and the number of slopes. For example, garages or other household buildings may have only one slope, barns have two such planes, but the roofs of civil buildings consist of two or four slopes. How to determine the angle of the roof in degrees, many builders are perplexed. According to experts, such calculations can be carried out using special matrices or graphs. In addition, you can find out the angle of the roof from the geometry course using a triangle. Most often described structural element reminiscent of this figure.

At the design stage of the roof, you need to select the necessary products and carry out necessary calculations. It is noted that the type of coating is taken into account when calculating the angle of any pitched structure. If the owner of the building does not know how to calculate the slope correctly, then this value is in the range of 9-20 degrees. When designing the roof of a building, consider the following nuances:

• the purpose of the building;
• the material from which the coating is made;
• climatic features of the construction region.

If you plan to install a roof with two or large quantity slopes, you need to pay attention not only to the listed requirements, but also to the construction area. It is also necessary to take into account the purpose attic space. If the attic will be used to store unnecessary things, then it makes no sense to make it high and increase the consumption of roofing material. When using a residential attic space, it is necessary to choose rafters with a maximum cross section and place them at a small distance from each other.

The dependence of the angle on the construction site

In regions with permanent strong winds slope should be kept to a minimum. In this regard, the load from air flows on the roof will be small. High roofs suffer from wind much more than low ones. This is not to say that the wind does not tear off the coating from roofs with a slight slope. Next, we will learn how to find the angle of inclination of the roof for buildings built in regions with constant winds:

• With a low intensity of air flow, the slope has a value of 34-40 degrees;
• In the presence of strong winds this figure is reduced to 15 ... 25 degrees.

In areas with a lot of precipitation, it is advisable to increase the slope to 60˚. Such a slope will allow you to quickly remove snow and water beyond the coverage. The roof slope usually varies in the range of 9 ... 60˚, but the range of 19 ... 44 degrees is considered the most common slope options.

Calculation example

And now let's take a look at how to calculate the angle of inclination of the roof using a specific example. First you need to find out the height of the ridge in relation to the base. This parameter depends on the purpose of the attic. If this room will be used as an attic, then we will need one more value - the length of the pediment or base.

How to measure the angle of inclination if the height from the base of the roof to the ridge is 1.8 meters, and the length of the gable is taken as a multiple of 6 meters. First you need to divide the "sole of the triangle" into two parts, and then calculate the sine of the angle using the Pythagorean theorem.

In our case, this is the value of the sine of the angle, which is found from the ratio of the adjacent side to the opposite side. First, we divide the triangle into two equal parts 6/2=3. Now we calculate the sine desired angle 3/1.8= 1.6. We look into the Bradis table and see that this value corresponds to an angle of 59 degrees.

Any house is crowned with a roof - one of the main structures of the building, protecting it interior spaces from rain and snow. One of the main criteria for any roof is the steepness of the slopes. Since a flat roof is distributed mainly only in multi-storey residential and industrial construction, this issue is especially relevant for owners of private houses and cottages.

The amount of roofing material depends on the size of the roof slope, so the choice of the angle of inclination and its preliminary calculations should be made before the purchase of roofing material.

Consider how to determine the angle of inclination pitched roof and its connection with the design of the entire roof structure.

In this article

What determines the slope of the roof?

The angle of inclination of the roof directly affects its performance characteristics. In construction, 4 types of roof structures are distinguished:

• Steep with a slope of 45-60°;
• Pitched - 30-45 °;
• Gentle - 10-30 °;
• Flat with a slope of less than 10°.

The definition of this value depends on a number of factors:

• The impact of the wind. The wind exerts the greatest pressure on steep roofs, as they have the greatest windage due to their large area surfaces. When arranging similar design important Special attention pay attention to the strength of the truss system.

In areas with a high wind load, it is also dangerous to arrange flat and sloping roofs: if the structure is weakly fastened, it may fail. Thus, in areas with strong winds, the recommended roof slope angle is in the range of 25-30°.

In areas where a significant amount of snow falls during the cold season, a steep roof, on the contrary, has advantages. Snow does not accumulate on it. With a smaller angle, the snow will lie on the roof longer, creating an additional load on truss system.

It is not necessary to equip a steep roof: a certain amount of snow lingering on the roof in winter period, It has useful property keep warm. However, it is important to calculate the load exerted by the snow cap on the structure in order to prevent its collapse.

• Roofing material. Each type of roof has its own restrictions on the angle of inclination of the slopes. If you plan to use a specific roofing material, then it is important at the design stage to correlate the desired slope of the roof with its technical specifications.
• Attic size. The angle of the roof directly affects the size of the room below it. The steeper the roof and the higher the ridge, the more spacious the attic and vice versa. When planning a room under a roof, one should not forget about the risks inherent in steep construction, and its high cost compared to the construction of more gently sloping roofs. A broken type can come to the rescue in this situation, which allows you to save the maximum volume for arranging the room, saving on the height of the ridge.

Minimum Tilt Angle

Such a concept as the minimum angle of inclination of the roof is related to the roofing material used. All roofs are supplied with technical specifications, which, among other things, clearly indicate the pitch limits for use. It is impossible to violate these rules, since in this case the roofing material will not retain its original functions and advantages.

Consider the main roofing and the minimum angles for them:

• Piece roofing materials (slate, tiles) are laid on roofs with a slope of 22 °. This indicator is due to the fact that in this case at the junctions roofing elements water does not accumulate and, accordingly, cannot seep under them;
• Working with roll materials the type of roofing material is important to determine in advance with the number of layers. If it is planned to lay 2 layers, then the roof angle should be at least 15 °, when laying 3 layers, this value can be reduced to 2-5 °;
• The professional flooring is mounted at a slope from 12 °. A lower value will require the treatment of all joints with sealant;
• The metal tile spreads at a value of 14 °;
• Ondulin - from 6 °;
• Soft tiles can be laid on a roof with a slope of 11 ° in the presence of a continuous crate;
• Membrane roofing materials are the only ones for which the minimum threshold is not indicated. They can be successfully used on flat roofs.

Following the above rules is extremely important, since even a slight violation of them will result in the destruction of the roof and, possibly, damage to the truss system.

Calculation of the angle of inclination

In addition to the minimum angle, there is such a thing as the optimal angle of inclination. With it, the roof is exposed to minimal possible loads from the side of wind, snow, etc. Let's give examples of such optimal values:

• In areas with frequent precipitation in the form of rain and snow, it is optimal to build a roof with a slope of 45-60 °, as it quickly gets rid of precipitation, which minimizes the load on the truss system;
• If the roof is being built in a windy region, then it will be good to place its angle of inclination in the range of 9-20 °. She will not play the role of a sail, catching the passing wind, but she will not capsize with its sharp gusts;
• In areas where both wind and snow occur regularly, average values ​​of 20-45° are used. This range can be called universal for pitched structures.

Independent calculation of the angle of the slopes is reduced to a simple geometric process, which is based on a triangle. Its legs are the height of the ridge and half the width of the house, the hypotenuse is one of the slopes. And the angle between the hypotenuse and the leg is the desired value of the steepness.

The angle of the roof is in direct relation to the height of the ridge. There are two options for calculating these values:

• Known roof height. If there is a desire to equip a spacious roof under the roof living room with an acceptable ceiling height, then the height of the ridge can be determined in advance. Having known two legs, it is easy to find out the value of the desired angle.

We accept the following notation:

• H is the height of the ridge;
• L is the width of half of the house;
• α is the desired angle.

We find the tangent of the desired angle using the formula:

tg α =H/L

We learn the value of the angle from the obtained value from a specialized table of tangents.

• Pre-determined angle of inclination. If you want to use a specific roofing material or due to weather conditions in the region, the roof slope can be determined in advance. By its value, you can determine the height of the ridge of the house and check whether it is possible to create a living room under this roof. For the arrangement of the premises, the height of the ridge must be at least 2.5 m.

We leave the conventions from the previous example and substitute the known values ​​​​into the following equation:

H=L*tg α

Thus, the process of calculating the angle of inclination is much simpler and faster than the analysis of all populations to determine its optimal value for a particular region and building.

Due to the fact that the pitched roof rests on walls that have different height, then the calculation of the given angle of inclination is carried out by simply raising one of the walls of the house.

We draw a perpendicular along the wall L sd (the length of the wall of the house), originating at the point where the short wall ends and resting on the wall with the maximum length.

If the length of the wall of the house L cd is 10 meters, then in order to get an angle of inclination of 45 degrees, the length of the wall L bc must be equal to 14.08 meters.

Conclusion

In roof design, finding the optimal angle of inclination has importance. This parameter depends on the correct estimate weather conditions, the choice of roofing material, the desire to create a living space. Its correct definition is the key to a long and successful roof service in all weather conditions.

The roof is an important structural part of the house, performing a number of the most important functions. It protects against atmospheric adversity and removes precipitation, provides insulation and makes a solid contribution to the formation of its own building style. In order for such a significant structure to "excellently" cope with the entrusted work, it is necessary to thoroughly think over the project and scrupulously figure out the dimensions.

Careful analysis and calculation gable roof required by both independent craftsmen and owners of suburban property using the services of construction organizations. Let's figure out how to do it right.

The roof, resembling an inverted V in a section, leads the list of pitched structures for a reason. In terms of simplicity of construction and economy, a gable roof has practically no rivals. For centuries, proven in practice, they are the basis for the construction of most roofing structures.

Unpretentious pitched planes do not require complex cutting of the coating and other materials, which results in an impressive amount of waste. No specific tricks are needed to implement intricate configurations. Precipitation does not linger on sloping surfaces, so there is no need to strengthen the waterproofing. As a result, the installation of a gable roof is often cheaper than a shed roof.

A roof with two slopes can be an independent object or part of a complex of structures of a similar or different form. The simplest version of it does not have built-in dormer windows and canopies over entrance porch, i.e. there are no additional fractures, ridges and accompanying valleys.

The absence of convex and concave corners deprives the master of "pleasure" to suffer with a number of difficult operations. Again, the owners will not get imaginary pleasure from leaks, which often appear at the joints of the pitched roof elements.

In principle, no one bothers fans of bizarre architecture to equip two slopes with numerous built-in structures. True, there are limitations on climatic grounds: in areas with a high volume of winter precipitation, the construction of roofs with numerous components is undesirable. In the grooves formed by excesses are created favorable conditions for the accumulation of snow deposits. They will have to be cleaned faster than usual, and excessive zeal in the field of snow removal can cause damage to the coating with all the consequences.

However, adherents of simple and clear forms should not relax either. The corner roof configuration must be perfectly matched and calculated, otherwise it will not be able to perform the entrusted work flawlessly.

Despite the deceptive elementality, in the definition optimal shape designs have tricks. It is impossible to overcome and circumvent them without knowledge technological subtleties, because all the parameters of the structure are interconnected:

• The width of the gable roof depends on the dimensions of the box and the type of coating, which in turn affects the selection of the steepness of the slopes.
• The slope of the roof depends on the climatic features of the construction area and on the type of roofing material.
• The combination of the above circumstances, width and slope, determines the height of the structure, which in the end may not meet architectural requirements and aesthetic considerations.

The impeccably designed roof has all the proportions perfectly matched. Its width and height determine the rise and slope necessary for the removal of precipitation in a particular area. Lower is impossible for technical reasons, higher is expensive and unreasonable, unless the unique architecture requires it.

Note that, coupled with an increase in steepness, the construction budget also increases. According to the slope, roofing material is selected. Focusing on its weight and specifics, they design and calculate truss frame. The calculation of the truss frame is carried out taking into account the listed parameters and taking into account the loads acting from the outside on the structure.

The interdependence of the proportions of the roof, the complexity of the device of the truss frame and the nuances of the selection of the coating makes it necessary to determine best form by random selection. If something does not fit, replace or strengthen bearing structures. Fortunately, and the assortment on construction market now ample, and all sorts of ways have been developed to strengthen the structure.

If you are afraid of the upcoming calculations and shuffling of data, it is better to resort to a win-win solution - standard project. It is not for nothing that abroad all the houses of one settlement are equipped with roofs of equal height and covered with material of the same color and characteristics. Typification allows you to maintain landscape identity and reduce design costs.

However, even a typical design solution is not a panacea for technical troubles and aesthetic shortcomings. We must not forget about the individual dimensions of the box over which it is planned to build a roof. Compatriots deny leveling in height and steepness, so we still want to deal with the proportions roof structure.

Step by step calculations

The configuration and dimensions of any pitched roof are set by the truss frame. On the ribs rafter legs slopes are laid, forming a dihedral angle. They construct truss systems from rolled metal and wood, use industrial structures and lumber in construction.

Let's take a look at the options available for the effort independent master, i.e. construction method of erecting a roof frame from lumber.

Stage # 1 - choosing the type of truss system

The method of constructing a gable roof is indirectly related to the dimensions, but without taking into account the difference in the arrangement of structures, it will be difficult to understand the geometric parameters.

In the construction of gable roofs, two traditional technologies are used:

• Layered, according to which the top and bottom of the rafters have a strong fulcrum. The walls of the house, equipped with a Mauerlat, serve as the lower support. The top of the layered rafter legs rests on a running beam that forms a ridge. The girder is supported on a specially built for it support system, on the inner wall or on the stone pediments of the box, erected to the roof device. The layered method is mainly used in the arrangement of large houses with an internal bearing wall or near columns.
• hanging, according to which the tops of the rafters rest only against each other. The walls serve as a support for the bottom, as in the previous case. Hanging rafter legs form equilateral triangle, whose base is called the puff. Taken together, such a system does not create thrust, i.e. does not transfer the bursting load to the walls of the box. Rafter triangles are installed either ready for installation, i.e. assembled on the ground, or constructed from separate rafters on site. The absence of an upper support makes adjustments to the scope of use: the hanging method is used in the arrangement of only small buildings with small spans.

Schemes of truss systems of both types include a minimum structural elements when overlapping boxes up to 8-10m wide.

When arranging spans larger, there is a danger of deformation of the rafter legs. To eliminate sagging and deflection wooden parts from lumber, install reinforcing elements: struts, contractions, side runs, etc.

Additional details provide rigidity and stability of a large structure, but increase the load. How the total load is determined and produced, we have already analyzed.

Step #2 - Width Calculation

Both types of wooden truss systems are built along the floor beams or along the Mauerlat. How the width of the roof is calculated depends on the type of base:

• When mounted on floor beams, it is they who form the cornice overhang, i.e. determine the dimensions of the roof.
• When installed on a Mauerlat, the width of the roof is determined by adding three values. You need to sum up the width of the box and two projections of the width of the cornice overhang. However, only the bearing part of the width of the roof, equal to the width of the box, is used in the calculations.

Mauerlat function in frame buildings performs top harness, at the same time connecting disparate elements into a single frame. AT wooden construction the Mauerlat is the upper crown, folded with a bar or log.

In the case of using the "beam" scheme of the device, the so-called mats are used - bars or logs laid under the upper crown of the foot as an overlap.

Cornice overhangs roofs mounted on a mauerlat can be formed directly by rafter legs, fillies sewn to them or a brick ledge. The latter option, of course, is used in the construction of brick walls. The choice of overhang width is dictated by the type roofing and the material from which the walls are composed.

• For slate roof no more than 10cm;
• For bituminous tiles in the range of 30-40cm;
• For metal tiles 40-50cm;
• For profiled sheet 50cm;
• For ceramic tiles 50-60cm.

Walls made of logs and timber require enhanced protection from slanting rains, therefore the overhangs above them are usually increased by 10-15 cm. If the limit value of the overhang width recommended by the manufacturer is exceeded, it is necessary to provide for measures to strengthen it.

It is possible to install external struts on the walls or support pillars, which can simultaneously play the role of structural elements of the terrace, porch, veranda.

Stage # 3 - determining the slope

The angle of inclination of the slopes is allowed to vary over the widest limits, on average from 10º to 60º s tolerances round trip. Traditionally, both planes of a gable roof have equal angles of inclination.

Even in asymmetrical structures for residential buildings, they are mainly located under equal angle, and the effect of asymmetry is achieved by constructing different-sized slopes. Most often, differences in the slope of the main parts of the roof are observed during construction. country houses and household items.

The procedure for determining the optimal steepness of a gable roof is significantly influenced by three factors:

• The type of coating, coupled with the weight of the crate intended for it. The type of roofing material determines the installation technology and the method of arranging the base for its fastening. The denser the roof is, the lower the value of the slope can be. The fewer overlaps and joints between the elements of the coating, the lower the roof is allowed to be. And vice versa.
• Roof weight with. A heavy coating located at an angle to the horizon presses on the base only with its projection. In short, the higher the slope, the less mass is transferred to the floor. Those. under a heavy roof you need to build a steep roof.
• Climatic specificity of the region. The high slope helps to quickly drain snow and water, which is highly desirable in areas with significant rainfall. However, high slopes are very sensitive to the effects of winds that tend to overturn them. Therefore, in regions with characteristic strong winds, it is customary to build gently sloping structures, and in areas with abundant rainfall, roofs with a high slope.

In the regulatory documentation used in calculating the angles for the construction of gable roofs, there are units that can confuse inexperienced home builders in roofing. The most simple quantity expressed in dimensionless units, the most understandable - in degrees.

The second version conveys the ratio of the height of the roof to half its width. To determine it, a line is drawn from the central point of overlap to the top of the roofing triangle. The real line is drawn on the diagram of the house, imaginary at the facility. The value is indicated either as a percentage, or as a mathematical ratio such as 1: 2.5 ... 1: 5, etc. In percentages, it is wiser and more inconvenient.

Stage # 4 - determining the height of the skate

A roof with two slopes, at the request of the owner, may or may not have an attic. In the attic spaces of gable roofs, it is not supposed to arrange useful premises. There is for this. However, the height of the attic used for servicing and inspecting roofs at an angle is not arbitrary.

According to the requirements of the fire service from the top to the ceiling should be at least 1.6 m. The upper limit is dictated by the aesthetic beliefs of the designers. They argue that if the height of the roof is greater than the height of the box, then it seems to “press” on the building.

The height of the ridge top for those arranged along the beams hanging roofs The easiest way to determine the drawing method:

• We draw a diagram of the box of the house on a scale.
• We are looking for the middle of the upper floor.
• From the middle up we lay the axis of symmetry.
• On either side from the middle, we set aside half the width of the roof - we get the extreme point of the overhang.
• With the help of a protractor, from the extreme point of the overhang, we draw a straight line at an angle recommended by the roofing manufacturer. The point of its intersection with the axis will be the top of the roof. We measure the distance from the top to the overlap, we get the height.

To get a complete picture, on the diagram you need to draw a second slope in a similar way. Parallel to the lines of the drawn slopes, two more lines must be drawn at a distance equal to the thickness of the rafter legs on the same scale.

If the configuration of the roof does not suit you, you can "play" with the height on paper, changing the position of the vertex point and the slope of the roof within reasonable limits. The same manipulations can be carried out in one of the drawing programs.

When drawing the outline of a roof constructed using layered technology, the thickness of the running beam should be taken into account. With impressive power, it will slightly shift the position of the slopes.

Craftsmen believe that the calculations of the elements of the truss system for the construction of a gable roof can generally be reduced to calculating only the section of the run. This is the most loaded element, all the others have the right to be thinner. For example, if calculations show that for ridge run material 100 × 150mm is required, then for rafters, supports, struts, a board of 50 × 150mm is enough.

The process of finding the height of structures with overhangs formed by filly is slightly different from the described method. It’s just that the slope angle is drawn not from the extreme point of the overhang, but from the lower attachment point of the rafter to the Mauerlat. In any case, it is better to choose variations with the steepness and dimensions of the gable roof planned for construction on “paper” than on the construction site.

Stage # 5 - calculation of material consumption

A normal owner thinks ahead of time about the construction budget. True, in the preliminary estimate, by definition, there will be inaccuracies. The process of erecting a gable roof will impose its own adjustments on the initial calculation of the material, but it will help to find out the amount of basic expenses.

The preliminary estimate should include:

• Beam for the Mauerlat device. In residential construction, lumber with a cross section of 100 × 150 mm to 200 × 200 mm is used. The footage is calculated around the perimeter of the box with a 5% margin for processing and connections. A similar material is purchased for the bed device, if it is designed.
• Board for the manufacture of rafters. Most often, for the manufacture of rafter legs, material is used with a cross section from 25 × 150 mm to 100 × 150 mm. The footage is determined by multiplying the length of the outer edge by the number. The material is purchased with a margin of 15-20%.
• A board or bar for making struts, puffs and supports with a section of 50 × 100, 100 × 100 mm, depending on the project. You also need a margin of about 10%.
• Material for the device of the crate. Its consumption depends on the type finish coat. The crate is constructed either solid, if it will be produced, or sparse for corrugated board, metal tiles, ordinary tiles, slate, etc.
• Roll waterproofing, the footage of which determines the type of roof and the steepness. High roofs are covered with a waterproofing carpet only along the overhangs, the ridge and in convex or concave corners. Gentle ones are covered with a continuous carpet.
• Finish coating. Its amount is calculated by summing the area of ​​​​the slopes. If there are embedded dormer windows, then their areas are also calculated. Only calculated as a rectangle, not in fact. The amount of laying stock is recommended by the coating manufacturers.
• Material for sheathing gables and overhangs.
• Corners, plates, self-tapping screws, staples, nails. We need anchors and studs, their number will tell the project.

You will also need shaped elements for arranging through passages through the roof, valleys, overhangs, ridge. The cost estimate presented is valid for a cold design. For an insulated roof, it will be necessary to purchase a heater and vapor barrier film, a bar for the counter-batten and material for roof sheathing from the inside.

We have selected for you a number of video clips in which construction technologies are analyzed in more detail:

To calculate everything before building a roof with an angle is a necessary and very useful thing. Despite the uncomplicated form and ease of installation, there are technological nuances in the process of calculations and construction. Preliminary design and sizing will help to take them into account and correctly apply.

Online calculator for calculations pitched roof will help to calculate the optimal angle of inclination of the slope, the size and total number of rafters, battens, as well as the amount of materials required for the construction of the roof. The calculator base contains popular roofing materials: slate, ondulin, cement-sand, ceramic and shingles, metal tile. This calculator allows you to calculate the dimensions of both sloping and flat roof.

The calculations take into account the parameters given in the TCP 45-5.05-146-2009 and SNiP "Loads and Impacts".

Shed is the simplest type of roof used in buildings today. Such a roof requires a minimum consumption of materials and labor costs, since there is only one slope in it. This type of roof is often found in modern buildings, as a rule, these are outbuildings, sheds, garages and other similar structures. Such a roof may include an attic or do without it.

For erection of this type roofs apply different kinds roofing and insulation materials. The angle of inclination for a shed roof can be anything, however, in most cases, small angles are used, up to a flat roof. The smaller the angle, the more important it is to clear the roof of snow in a timely manner, since the load on the roof increases along with a decrease in its slope.

When entering data into the calculator, be sure to check with additional information marked with this icon. Here you will find additional information.

At the bottom of the page, you can leave feedback, ask your own question to the developers, or suggest an idea to improve the calculator.

Explanation of calculation results

Roof slope

At this angle, the rafters and roof slope are inclined. The calculator not only takes into account the angle you specify, but also determines how compatible it is with your chosen roofing material. You can change the angle of inclination of the roof through the width of the base or the height of the roof.

Roof surface area

The total area of ​​the roof (including overhangs of a given length). Determines the amount of roofing and insulation materials that will be needed for the work.

Approximate weight of roofing material

Estimated weight of your chosen roofing material required to cover the entire roof.

Number of rolls of insulating material

Determines the total amount of insulation material based on a roll length of 15 meters and a width of 1 meter. Calculations are made taking into account 10% overlap.

Maximum load on the truss system. The calculations take into account the weight of the entire roofing system, roof structure, as well as wind and snow loads in the region you specified.

Rafter length

The total length of the rafters from the beginning of the slope to the ridge of the roof.

Number of rafters

The total number of rafters required to build a roof with a given pitch.

Minimum section of rafters, Weight and Volume of timber for rafters

The table shows the recommended sizes of rafter sections (according to GOST 24454-80 Softwood lumber), which you can use when building a roof with the given parameters. The calculation is performed taking into account the specified roofing material, area, angles and regional loads. The adjacent columns display the total weight and volume of these rafters for the entire roof structure.

Number of rows of battens

The total number of rows of sheathing for a roof of given dimensions. We also recommend that you consult with the sellers of the roofing material you have chosen regarding the required step of attaching this material to the crate. This may adjust the pitch or dimensions of the crate you specified.

Uniform spacing between boards

To evenly install the crate, avoiding unnecessary overspending, use given value.

The number of boards of the crate with a standard length of 6 meters

For the crate of the entire roof, you will need this number of boards. Used in calculations standard length boards - 6 meters.

The volume of boards of the crate

The required volume of boards for the crate in cubic meters.

Approximate weight of batten boards

Estimated total weight of the boards of the crate. To calculate the mass, the average values ​​​​of density and moisture for coniferous wood are used.

The slope of the roof slopes - what it depends on and how it is measured.

Such an important fact for the roof is its slope. Roof slope- this is the angle of inclination of the roof relative to the horizontal level. According to the angle of inclination of the roof slopes there are low-slope(sloping), medium inclination and roofs with steep(highly inclined) stingrays.

low slope roof that roof, the installation of which is carried out based on the smallest recommended angle of inclination of the slopes. So for each roofing there is a recommended minimum slope.

What determines the slope of the roof

• From the ability of the roof to protect the structure from external factors and impacts.
• From the wind- the greater the slope of the roof, the more value attributable wind loads. With steep slopes, wind resistance decreases, and windage increases. In regions and places with strong winds, it is recommended to apply a minimum roof slope to reduce the load on the roof's load-bearing structures.
• From roofing (material) - Each roofing material has its own minimum angle of inclination at which this material can be used.
• From architectural ideas, solutions, local traditions- so in different regions preferred for a particular roof structure.
• From atmospheric precipitation: snow loads and rainfall in the region. On roofs with a large slope, snow, dirt and leaves will not accumulate in huge quantities.

What is the roof pitch measured in?

The designation of the roof slope in the drawings can be either in degrees or as a percentage. The slope of the roof is indicated by the Latin letter i.

In SNiP II-26-76, this value is indicated as a percentage (%). AT this moment there are no strict rules for designating the size of the roof slope.

The unit of measure for roof slope is degrees or percentages (%). Their ratio is shown in the table below.

Roof slope degree-percentage ratio

degrees	%		degrees	%		degrees	%
1°	1,75%		16°	28,68%		31°	60,09%
2°	3,50%		17°	30,58%		32°	62,48%
3°	5,24%		18°	32,50%		33°	64,93%
4°	7,00%		19°	34,43%		34°	67,45%
5°	8,75%		20°	36,39%		35°	70,01%
6°	10,51%		21°	38,38%		36°	72,65%
7°	12,28%		22°	40,40%		37°	75,35%
8°	14,05%		23°	42,45%		38°	78,13%
9°	15,84%		24°	44,52%		39°	80,98%
10°	17,64%		25°	46,64%		40°	83,90%
11°	19,44%		26°	48,78%		41°	86,92%
12°	21,25%		27°	50,95%		42°	90,04%
13°	23,09%		28°	53,18%		43°	93,25%
14°	24,94%		29°	55,42%		44°	96,58%
15°	26,80%		30°	57,73%		45°	100%

You can convert the slope from percent to degrees and vice versa from degrees to percent using the online converter:

Roof pitch measurement

The slope angle is measured using an inclinometer or mathematically.

Inclinometer- this is a rail with a frame, between the slats of which there is an axis, a division scale and to which a pendulum is fixed. When the rail is in horizontal position, shows zero degrees on the scale. To measure the slope of the roof slope, the inclinometer rail is held perpendicular to the ridge, that is, in vertical level. On the scale of the inclinometer, the pendulum indicates the slope of a given roof slope in degrees. This method of measuring the slope has become less relevant, since now there are various geodetic instruments for measuring slopes, as well as drip and electronic levels with inclinometers.

Mathematical calculation of the slope

• Vertical Height (H) from top point slope (usually a skate) to the level of the lower (cornice)
• Foundation ( L ) - horizontal distance from the bottom of the slope to the top

Using a mathematical calculation, the value of the slope of the roof is found as follows:

The angle of the slope of the slope i is equal to the ratio of the height of the roof H to the laying L

i \u003d H : L

In order to express the slope value as a percentage, this ratio is multiplied by 100. Further, to find out the slope value in degrees, we translate according to the ratio table above.

To make it clearer, let's look at an example:

Let it be:

Laying length 4.5 m, roof height 2.0 m.

The slope is: i = 2.0: 4.5 = 0.44 now multiply by × 100 = 44%. We translate this value according to the table into degrees and get - 24 °.

Minimum slope for roofing materials (coverings)

Roof type	Minimum roof pitch
	in degrees	in %	in the ratio of the height of the slope to the laying
Roll roofs bituminous materials: 3 and 4 layers (welded roofing)	0-3°	up to 5%	until 1:20
Roofs made of rolled bituminous materials: 2-layer (welded roofing)	from	15
seam roof	from 4°
Ondulin	5°		1:11
Wavy asbestos cement sheets (slate)	9°	16	1:6
Ceramic tiles	11°		1:6
bituminous tiles	11°		1:5
metal tile	14°
Cement-sand tiles	34°	67%
wooden roof	39°	80%	1:1.125