Calculate the area of a sloping roof online calculator. Calculation for the construction of a mansard roof

Online calculator mansard roof will help to calculate the angles of inclination of the ridge and side slopes of the roof, the number and minimum cross section of the rafters, the volume of the sheathing and materials that will be needed to build the roof. Before designing the attic floor, read SNiP 2.08.01-89 "RESIDENTIAL BUILDINGS".

In calculations this calculator the parameters given in TKP 45-5.05-146-2009 and SNiP "Loads and Impacts" are taken into account.

A mansard (also broken, sloping) roof is a roof that has two slopes with different angles of inclination on each side. This technique helps to optimize the space under the roof and create a comfortable room under the roof (attic or attic floor). Similar roofs have been known since the 17th century. Today, the mansard roof has many varieties. In the attic can be both economic and residential premises.

A mansard roof can be built both at the first stage of construction, and built on top of an already finished building. Thus, the building can be enlarged living space without the need to build a full-fledged second floor.

When building a mansard roof, you need to take into account its specifics: the steep slopes of the side slopes require increased costs for the arrangement of the roof. Also, the attic floor needs enlarged windows and additional thermal insulation, especially if the premises in it are intended for housing.

When filling in the fields of the calculator, you can check additional information marked with an icon.

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Explanation of calculation results

Angle of inclination of the side rafters

At this angle, the side (steeper) rafters and the side slope of the roof 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. To change the angle of the slopes, you need to change the Laying Width (A1, A2) or the Lift Height (B1, B2).

The angle of inclination of the ridge rafters

The upper (hanging) rafters and the upper (sloping, ridge) roof slope are inclined at this angle. The calculator not only takes into account the angle you specify, but also determines how compatible it is with the selected roofing material. To change the angle of the ramps, change the Laying Width (A1, A2) or the Lift Height (B1, B2).

Roof surface area

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

Attic floor area

The total area of the attic (living area of the attic). Does not include space under side roof slopes.

Approximate weight of roofing material

Estimated total weight of roofing material required to completely cover the roof area.

Number of rolls of overlapping insulation material

The total amount of insulation material in rolls that will be required to insulate the roof. The calculations are based on rolls 15 meters long and 1 meter wide. An overlap of 10% is taken into account.

Load on the side / ridge truss system

Maximum load per lateral/ridge truss system. The calculations take into account the weight of the entire roofing system, the shape of the roof, as well as the wind and snow loads of the region you specify.

Side rafter length

It is measured taking into account the overhang of the roof to the junction with the ridge rafter.

Ridge rafter length

Measured from the joint with the side rafter to the roof ridge.

Number of side and ridge rafters

The total number of side and ridge rafters necessary for the construction of a roof with a given pitch.

Minimum section of side/ridge rafters, Weight and Volume of rafter beam

The tables show the recommended sizes of rafter sections (according to GOST 24454-80 Softwood sawn timber). The calculations take into account the roofing material, the area and shape of the roof structure, as well as the loads exerted on the roof. The adjacent columns show the total weight and volume of the rafters, based on their use for the entire roof structure.

Number of side/ridge rows of battens

The total number of side and ridge rows of battens required for the calculated roof.

The total number of rows of crates

The total number of rows of sheathing for the entire roof. To determine the number of rows of battens for half the roof, it is enough to divide the resulting value by two.

Uniform distance between the side/ridge boards of the purlin

To evenly install the batten and avoid unnecessary waste of materials, the value indicated here should be used.

Number of batten boards in standard length

For the roof sheathing, you will need the number of boards indicated here. When calculating, a standard 6-meter board length is used. The number of boards for the entire roof is indicated.

The volume of boards of the crate

The volume of boards in cubic meters will help you calculate the cost of the cost of the crate. The total volume of the crate for the entire roof is indicated.

Approximate weight of batten boards

Estimated total weight of all boards of the crate. The calculations use average density and moisture values for softwood.

The attic floor is the last in the house. To facilitate the design and load, lighter materials are used for its construction. The layout of the attic may differ from the lower floors. It can have its own unique windows and interior decoration. All this can be done if you correctly draw up an attic project and carry out the necessary calculations.

Varieties of attics

attic room in own house has many positive qualities, of which the main one is the presence of additional living space. The equipment of attic structures in the attic room can be carried out both in a house under construction and in a finished one. To do this, you must comply with the requirements normative documents during the construction of the attic and draw up the necessary drawings.

The attic should be located within bearing walls buildings and do not exceed this distance. Drawings of premises can have any form, depending on the purpose of the premises. There are three types of attic structures:

With the equipment of a separate floor on the same level.
With two levels of development.
With free floor equipment.

Based on the height, there are three types of attic:

Half attic. With a wall height of up to 0.8 meters.
Attic. With a front wall height of 0.8 to 1.5 meters.
Full floor. With a front wall height of 1.5 meters.

Mansard roof and its elements

There are several roof options for building equipment. They differ from each other not only in shape, but also in the type of construction and are divided into: two, three and four-slope, broken two-slope, half-hip and hip.

A gable roof is easy to install and can withstand high loads. It has symmetrical slopes and a triangular front view. With a building width of up to 6 meters, the slopes can have an angle of inclination of up to 45 degrees. If the width exceeds a distance of 6 meters, then the requirements of regulatory documents allow you to increase the specified angle to 60 degrees.

Three and four-pitched roofs have slopes of various sizes, with different mounting angles. Because of this, they are often called asymmetrical. The existence of such wooden structures give the building originality. But the installation of such a roof requires careful calculations and considerable financial costs.

The mansard broken gable roof is distinguished by the fact that its slopes are installed under different angle in relation to the base. An important positive aspect of such a roof is efficiency. roof structure and the ability to maximize the use of the internal area of the attic space.

Half hip and hip roofs are varieties of a simple gable. They form additional slopes from the front of the roof and its sides.

Components of the truss system

The bearing parts of the truss structure must be strong. Usually softwood is chosen for them. It almost does not give in to decay and is easy to process, withstands a sharp change in temperature and has a low specific gravity. The material prepared for installation must be treated with a refractory mortar and liquid to protect against wood pests and rodents. The truss structure includes several wooden and other elements: rafters, girders, mauerlat, crate, ridge, support post or strut, bed, puff and filly.

The rafters are the frame of the entire structure and are installed on the Mauerlat. The rafters are interconnected by girders and fastened with puffs. The outer crate is attached to the rafters and roofing material is mounted on it. In addition to the outer crate, there is also an inner one. Insulating material is laid between them. The battens perform an additional ventilation function. The slopes are combined into a skate. The bed is installed from the front wall to the ceiling, and struts and racks are mounted on it to give strength. To increase the length of the rafters of the structures, fillies are used, which increase the overhang of the roof.

Mauerlat and its fasteners

Mauerlat is the part of the truss system that holds the roof. Mauerlat is mounted along the entire carrier contour attic floor and is the basis of the entire truss system. The installation of the wooden parts of the Mauerlat is carried out directly on the armored belt. In this embodiment, the Mauerlat acquires greater rigidity. In addition, it serves as a connecting element between the roof and walls of the building.

Fasteners for Mauerlat must have a high margin of safety. Most often, the fastening of the Mauerlat is carried out using threaded studs, which are attached to the metal fittings located inside the formwork using a knitting wire. The diameter of the stud must be at least 10 mm. The length of the stud should exceed the thickness of the Mauerlat by 20-30 mm. The hole for the stud must be made in the place of the Mauerlat, on which the rafters will not rest, ideally in the center between the rafters. In this case, the pitch of the holes should be less than 1 meter. To do this, before installation, it is necessary to carry out the correct calculation of those places that will be drilled under the mounting stud.

Sloped roof calculation

The sloping mansard roof is the most popular. This is due to the fact that the shape of the roof allows you to maximize the usable area. On the example of such a roof, it is possible to calculate the components of the attic level. Before they are carried out, it is necessary to draw up a project and drawings for it.

Payment broken structures carried out according to the following components:

area calculation roofing;
determination of the angles of installation of the roof, in accordance with the way they were applied to the drawings;
calculation of the total mass of building materials for roofing equipment;
calculation of wooden rafters;
calculation of the dimensions of the side, ridge rafters;
determination of the size of the crate;
choice of insulation, calculation of the load on the truss system.

Now let's look at each item element by element.

Calculation of the dimensions of the roof and its angles of inclination

In order to calculate the total area of \u200b\u200bthe roof, it must be divided into figures. To do this, it is necessary to draw up drawings of the section of the attic room. The result will be trapezoids, rectangular and triangular shapes. Calculations of such structures and drawings for them are very simple. The areas of the figures are calculated separately. After that, the data of all figures are added to the total value.

The area of a rectangle is defined as: S = A x B, where A and B are the length and width, respectively.

The area of a triangle is calculated by the formula: S \u003d (A x h) / 2, where A is the width of the base, h is the height of the triangle

The area of the trapezoid is calculated: S = ((A + B)/2) x h, where A and B are the lengths of the lower and upper bases of the trapezoid, respectively, h is the height of the trapezoid.

The mounting angles of the slopes of broken structures are determined by special formulas. Drawings and calculations of the roof installation angles should be included in the overall design of the attic floor.

The installation angle of the side rafters of such a roof ranges from 55 to 65 degrees, and the installation angle of the upper part of the roof is about 30 degrees. The drawings made according to the calculations, indicating the dimensions, areas and angles of installation of the structure, can be used as the basis for the project.

Installation of attic rafters and roofing

The calculation of the load and weight of the material for roofing equipment is mandatory. The cross section directly depends on this value. rafter legs, as well as the distance between them during installation. The calculation of the mass of materials is carried out from the ratio per 1 square meter. After that, knowing the total area of the roof, the total mass of the roof is determined. If slate is used as a roofing material, then the approximate weight will be 11-14 kg / sq.m. For soft tiles this weight will be 9-16 kg / sq.m, zinc sheet - 3-6 kg / sq.m, ceramic tiles - 50-70 kg / sq.m.

To select the section and installation step of the rafters important role plays an average load. It should ensure the stability of the entire structure during heavy snowfalls and strong winds. For broken wooden structures, the average load must exceed 200 kg/m.p. To reduce the load on the roof, a correction factor is used. It is used when calculating the angles of the roof. If the slope is up to 20 degrees, then the coefficient is 1.5. At an angle of up to 55-65 degrees, the coefficient will decrease to 1.25. For roofs with a slope of 65 degrees or more, the amendment does not apply. It is easier to calculate such loads when the appropriate drawings are drawn up.

To calculate the total load on the building, in addition to the mass of the roofing material, the mass of the truss structure is determined. Take as a basis minimum size section of the rafters, which is 5x10 cm, and the density of wood with a moisture content of 18 percent. The mass of the rafter system with such parameters will be in the range of 500-600 kg / m3.

Due to the difference in the weight of the roof, the installation step of the rafters will change. With a minimum section of 5x10 cm, the installation step will have a distance of 80 cm if the roofing material is slate or ceramic tiles. When using metal tiles or ondulin as a roof, the installation step of the rafters will be a distance of 60 cm, and when using corrugated board - no more than 90 cm. Often, the rafter step is chosen according to the size of the insulation.

The choice of insulation and the calculation of the crate

Glass wool, polyurethane foam, extruded polystyrene foam, expanded polystyrene (polystyrene) are used to insulate the roof of the attic.

Mineral wool is most often used for thermal insulation of the attic roof. It has excellent fire performance, environmentally friendly, does not rot, can take desired shape, light weight and easy to work with. Expanded polystyrene (polystyrene) and its varieties have high thermal insulation characteristics, have a small weight, as a result of which it is possible to increase the thickness of the insulation.

The installation step of the crate and its density depend on the material of the insulation and the roof. The frame is made from wooden elements. If the roof is made of soft material, then plywood is used as a crate. For semi-rigid or rigid roofing material, a crate is installed with a board width of 20 cm and a step of 25-35 cm.

Determination of the dimensions of the side and ridge rafters

The calculation of the side and ridge rafters is carried out according to certain formulas. For skates, this is the formula for an equilateral triangle:

B \u003d B att / 2cosinus C,

where B is the length of the ridge rafter;

In zat - the length of the base or puff;

C - the angle of inclination of the rafters at the base.

Let's assume that the length of the base is about 4 meters, and the angle of inclination at the base is about 30 degrees. Substituting the data into the formula, we get the result:

B \u003d B zat / 2cosinus C \u003d 4 / 2x0.86 \u003d 2.3.

The length of the ridge wooden rafters is 2.3 meters.

To calculate the length of the side rafters, another formula is used:

B \u003d (B carn + H) / cosine Y,

where B is the length of the side rafter;

In karn - the length of the cornice;

H is the height of the support post;

U - the angle of inclination of the rafters.

We take as a basis the length of the cornice 0.5 m, the height of the support post 2.5 meters and the angle of inclination of about 60 degrees. After inserting the initial data into the formula, we will calculate:

B \u003d (B carn + H) / cosinus Y \u003d (0.5 + 2.5) / 0.5 \u003d 5.5.

The length of the side wooden rafters will be 5.5 meters.

Determination of the usable area of the attic

Before starting the construction and equipment of the attic floor, it is necessary to calculate its area. The calculation of the living area is made according to the formula:

S = A x B + 0.7 x C

S - attic area;

A - the total area of premises with a height of more than 2.5 meters;

B - the total area of premises with a height of 1.1 to 2.5 meters;

C - the total area of premises with a height of 0.8 to 1.1 meters;

0.7 is the correction factor. Applicable for more exact definition useful areas.

Skylights

The design of the attic space must have a section providing for installation and equipment window openings. The equipment is carried between the roof rafters. The width of the window opening should be less than the installation step of the rafters by 20 cm. In the places where windows are installed, to increase rigidity, transverse bars are installed in the rafter structure from above and below. Roof windows let in more light than front windows by 40-50%. The total area of window openings should not exceed 13% of the total roof surface. The distance from the floor to the bottom and top of the window opening should be less than 80 cm and not more than 220 cm, respectively.

Attic chimney and the need for insulation

The main function of the chimney is to remove smoke and combustion objects outside the building by means of draft. Combustion objects contain a variety of chemical compounds which, after combustion, are oxidized in contact with air. Oxidized, they settle on the inner surface of the chimney and eventually destroy it. Basically, such a reaction occurs from a change in temperature in cold weather, for example, at night. To prevent this from happening, the part of the chimney, which is located in the attic and above the roof, is equipped with thermal insulation. For chimney equipment, ceramic pipes or stainless steel are used. Most often, refractory bricks are used to build a chimney.

The thermal insulation of the chimney can be made in different options. For this, it is necessary to use materials that are specifically designed for this.

Ways of thermal insulation of chimneys

The main difficulty in installing a chimney is that it heats up during operation. The rafter system consists of wooden elements. When installing the roof and rafter system, it is necessary to maintain the distance between the chimney and the rafter system, to minimize the transfer of heat to flammable roof elements.

In order to prevent heating of the wooden parts, a two-sided protection called an apron is installed at the point where the pipe exits the roof. Its lower part is attached along the perimeter of the pipe under the roofing material. The upper half is also mounted along the perimeter of the chimney on top of the roof. For mounting the apron, galvanized steel is used.

Thermal insulation of chimneys is carried out depending on the type of chimney and is carried out in different ways.

If the chimney is brick, then several layers of lime and plaster are applied to it. To do this, a mounting grid, 2-3 cm thick, is attached over the entire area of \u200b\u200bthe pipe. When the grid is installed, the first layer of lime mass is sprayed. After the solution hardens, the second ball is sprayed, then the third and subsequent ones. After the desired thickness of the insulation is reached, the plaster is rubbed to a flat surface. If cracks appeared during the work, then they must be covered with the same lime mortar.

If used as a chimney asbestos pipe, that one is placed on top of it protective cover, which is 5-7 cm in diameter larger than the pipe itself. The free space between the pipe and the casing is filled with slag, stone or mineral wool and rammed.

In the same way, the thermal insulation of a smoke hood made of stainless steel is carried out.

After the thermal insulation of the chimney is completed, it can be finished with bricks.

Output

To make a full-fledged project, it is necessary to correctly calculate all the elements and details of the attic. If the calculation is made correctly, the construction technology and the requirements of regulatory documents are observed, then the attic room will serve for a long time.

Device attic at home

Take advantage online calculator ohm mansard roof for calculation required amount roofing materials of this type. Accurate calculation of the crate, the angle of inclination of the truss system, the load on the roof of the house.

Specify roofing material:

Select a material from the list -- Slate (corrugated asbestos-cement sheets): Medium profile (11 kg/m2) Slate (corrugated asbestos-cement sheets): Reinforced profile (13 kg/m2) Corrugated cellulose-bitumen sheets (6 kg/m2) Bituminous (soft , flexible) tiles (15 kg/m2) Galvanized sheet metal (6.5 kg/m2) Sheet steel (8 kg/m2) Ceramic tiles (50 kg/m2) Cement-sand tiles (70 kg/m2) Metal tiles, corrugated board (5 kg/m2) Keramoplast (5.5 kg/m2) Seam roof (6 kg/m2) Polymer-sand tile (25 kg/m2) Ondulin (Euro slate) (4 kg/m2) Composite tile (7 kg/m2) ) Natural slate (40 kg/m2) Specify the weight of 1 square meter of coating (? kg/m2)

kg/m2

Enter roof parameters:

Laying width A1 (cm)

Laying width A2 (cm)

Base length D (cm)

Lift height B1 (cm)

Lift height B2 (cm)

Length of side overhangs C (cm)

Front and rear overhang length E (cm)

Rafter:

Rafter pitch (cm)

Type of wood for rafters (cm)

Working section of the side rafter (optional) (cm)

Lathing calculation:

Purlin board width (cm)

Lathing board thickness (cm)

Distance between decking boards
(cm)

Snow load calculation:

Select your region using the map below

1 (80/56 kg/m2) 2 (120/84 kg/m2) 3 (180/126 kg/m2) 4 (240/168 kg/m2) 5 (320/224 kg/m2) 6 (400/280 kg/m2) 7 (480/336 kg/m2) 8 (560/392 kg/m2)

Wind load calculation:

Ia I II III IV V VI VII

Height to building ridge

5 m from 5 m to 10 m from 10 m

Terrain type

open area closed area urban areas

Calculation results

Angle of inclination of the side rafters: 0 degrees.

The angle of inclination of the ridge rafters: 0 degrees.

The angle of inclination is suitable for this material.

The angle of inclination for this material is desirable to increase!

It is desirable to reduce the angle of inclination for this material!

Roof surface area: 0 m2.

Attic floor area: 0 m2.

Approximate weight of roofing material: 0 kg.

Number of rolls of insulation material with 10% overlap (1×15 m): 0 rolls.

Rafter:

Load on the side truss system: 0 kg/m2.

Load on the ridge truss system: 0 kg/m2.

Side rafter length: 0 cm

Length of ridge rafters: 0 cm

Number of side rafters: 0 pcs

Reduce the pitch of the rafters!

Number of ridge rafters: 0 pcs

Reduce the pitch of the rafters!

Lathing:

Number of side rows of lathing (for the entire roof): 0 rows.

Number of ridge rows of lathing (for the entire roof): 0 rows.

The total number of rows of crates: 0 rows.

Uniform distance between the side boards of the crate: 0 cm

Uniform distance between the ridge boards of the crate: 0 cm

Number of batten boards standard length 6 meters: 0 pcs

Volume of boards of an obreshetka: 0 m 3 .

Approximate weight of the boards of the crate: 0 kg.

About the calculator

The online mansard roof calculator will help you calculate the angles of inclination of the side and ridge slopes, the number and required section rafters, the amount of lathing and other materials for the construction of the roof. You won't have to do extra calculations as this calculator includes most of the existing roofing materials such as shingles, cement-sand and ceramic tiles, metal tile, bituminous and asbestos-cement slate, ondulin. If you are using a non-standard material, or want to get more accurate calculations, you can specify the weight of your own roofing material by selecting the appropriate item in the drop-down list of materials.

Before designing an attic floor, read SNiP 2.08.01-89 "RESIDENTIAL BUILDINGS" in all seriousness.

Note!
The calculator makes calculations in accordance with the current SNiP "Loads and Impacts" and TCP 45-5.05-146-2009.

The device of the mansard (broken, sloping) roof is different in that on each side it contains two slopes with different angles of inclination: a steep lateral and a sloping hanging one. Thus, under the roof is formed comfortable space which can be used as a living space. This room is called the attic floor or simply the attic.

Attics were first built in the 17th century. The attic is relatively easy to build both during the initial construction of the building and as a superstructure on an existing building. Thus, it provides an alternative in the construction of an additional floor.

Since the side slopes are very steep, you should carefully choose building materials. Perhaps a mansard roof will require additional costs. This is especially important for residential attic rooms: They will need larger gable windows and improved thermal insulation.

When filling out the fields of the calculator, read the additional information located under the sign.

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