A rafter is a load-bearing roof structure that rests on load-bearing walls and is a support for the installation of roofing materials. Roof rafter drawings are designed taking into account the requirements of strength, rigidity - taking into account temporary and permanent loads.
Continuous loads are: the weight of the roof structure; periodic are: snow cover pressure, wind loads, people's weight during roof repair. When arranging the roof, the weight of building materials is taken into account. The weight of the truss systems should not greatly increase the load on the wall and foundation. Strict requirements are imposed on the quality of rafter materials.
The composition of the truss system:
Documentation for rafters - drawing, defines the structure of the roof, presents a visual image, helps to estimate the cost of materials. When designing a roof with an attic, the interior space is planned using the drawing. The rafter system includes:
I. The basis of the structure is Mauerlat: a beam that is strengthened along the walls of the building and holds the rafters.
II. Beams that determine the slope of the slope, and fix the structural elements - rafter legs.
III. Bars laid perpendicular to the rafter legs, which transfer the load from the roof and serve to lay the coating material - the crate.
IV. Retaining elements that serve to stiffen the structure:
a) racks;
b) ties;
c) struts;
d) lying down;
e) runs, etc.

Rafter plan drawing:
To bind the truss system to the load-bearing walls, the axes of the building are applied. Depending on the distance between the main walls, the design of the system is designed. Pipelines and ventilation ducts, chimneys are applied to the plan, with markings of the location relative to the racks. A device is drawn on the plan with incoming elements, connection nodes and dimensions that determine the relative position of the parts. The drawing indicates: the location of gables, attic windows, roof ribs, skates, etc.
Form of roof structures
I. Flat.
II. Shed.
III. Gable - consists of two inclined planes. From the end it has the shape of a triangle.
IV. Four-pitched: hip, half-hip, tent.
V. Vaulted.
VI. broken line.
VII. Pyramidal.
When building a building in areas with strong wind loads, a hip roof structure is used. Instead of the vertical walls of the pediment, there are triangular slopes, the other two slopes are trapezoidal: this is how hip roof rafters. Blueprints are created on the basis of calculations of the characteristics of the system. Calculated:
a) the height of the skate;
b) the length of the ridge beam and rafters;
c) the angle of the rafters;
d) roof area;
e) overhang extensions.
When designing buildings no more than 3 floors, a gable roof is used. Projects on the site gable roof rafter drawing, for different types of buildings.

03.11.2017

How to draw a roof plan. The subtleties of preparing a pitched roof plan. Stages of drawing up a drawing

In low-rise buildings, as a rule, attic pitched roofs on wooden rafters with a crate. slope roof is accepted depending on the material of the roof and the area of ​​construction. The minimum slopes of steel roofs are 14°, tiled roofs are 27°, corrugated asbestos-cement sheets are 18°. In areas with heavy snow cover, roof slopes of more than 30 ° should be taken.

The forms of attic roofs are determined by the outlines of the building in plan and the desire for architectural expressiveness. Roofs can be single-pitched, gable (the most commonly used), four-pitched (tent, hip, half-hip) and multi-pitched.

Drainage from the roof can be unorganized or organized. With an organized drain, the number of downpipes is taken at the rate of 1-1.5 cm 2 of the pipe section per 1 m 2 of the roof. The optimal distance between the drain pipes is 15-20 m. The removal of the roof eaves with an unorganized drain should be at least 500 mm, with an organized drain - at least 300 mm.

The load-bearing structures of the roof consist of rafters made of logs, beams or boards. The choice of the scheme of roof rafters is made depending on the width of the building and the nature of the location of the internal walls (supports), in accordance with the roof plan.

If there are internal load-bearing walls in the building plan, apply layered rafters, the main bearing elements of which

- rafter legs - work like obliquely laid beams, with the upper end resting on the ridge run, and the lower end on the Mauerlat of the outer walls. The maximum length of the rafter legs is no more than 6.5 m. If there are no intermediate supports in the building, then apply hanging rafters, which are the simplest type of truss truss, where inclined rafter legs transmit thrust to a horizontal puff.

The section of the elements of the rafters is taken constructively, by analogy with typical parts and textbook data. In order to avoid condensation and freezing of the insulation on the attic floor, it is necessary to provide through ventilation of the attic through dormer windows. Particular attention should be paid to the location of the Mauerlats, girders, racks, the development of nodes and the linking of the mates of individual roof elements to each other.

The gable roof system is a classic mansard roof design. They belong to the most common type of engineering solutions - tongs.

Important! Broken mansard roofs are variations of gable roofs. They can be located symmetrically and asymmetrically, be in one and two levels.

The optimal angle of inclination of a gable roof is 30-60 degrees. The sloping roof version reduces the total load on the load-bearing walls, distributing it over the surface. The advantage of this design is resistance to various weather conditions. The hip roof system is a four-pitched type of roof. The end surfaces (hips) are triangular in shape, the pitched surfaces are trapezoidal. There are modifications:

• Danish roof - combines in its design a gable and hip roof;
• half-hipped roof.

Hip roof truss system

A hipped roof system is a four-pitched roof, consisting of four isosceles triangles, closing with their vertices in one place. Very well suited for square buildings. A necessary condition for the construction of such a structure is the symmetry of all elements. The multi-gable roofing system is a complex multi-angled structure. May be at different levels. Such a system evenly distributes the load on the roof surface. It has a large number of internal and external angles of inclination with different values, as well as a large number of ribs-slopes.Dome (conical) roofing system - suitable for round structures. It is extremely rarely used in the construction of attic houses. But it looks great when building round turrets.

Advantages and disadvantages of pitched roofs

The simplest installation option is a pitched roof. Reinforced concrete slabs can be used as a material for construction. However, a more common mounting option is using a truss system. Advantages of shed truss roof structures:

2. You can do the installation yourself.
3. Light weight construction. Suitable for houses with light foundations.
4. It is mounted both on high-rise buildings and structures, and on small outbuildings on a private plot.
5. It is easy to equip the attic.
6. In open windy areas, single-slope structures with a small angle of inclination are used.

The disadvantages of single-slope structures include:

1. Low resistance to snow loads.
2. Increased waterproofing to prevent leaks. Permanent seasonal inspection and repair of small cracks and pits.
3. Cumbersome design appearance.

One of the simplest roof structures is a shed roof, its construction is within the power of even slightly experienced builders.

The most optimal angle of inclination of a shed roof is an angle of 45 degrees. It is recommended to construct such roofs in the southern windy dry areas. The arrangement of a shed roof in the northern snowy regions is highly discouraged.

Rules for installing the truss system

Rafter roofing systems are built according to the following rules:

1. The cross section of the beams cannot be less than 100x100 mm.
2. Mandatory waterproofing.
3. The bearing units fixed with brackets must be additionally fastened with steel strapping.
4. The moisture content of wooden elements should not exceed 10%.
5. All wooden elements are necessarily treated with an antiseptic and mosquito repellents.

Important! The best rafter material is needles. It is the most resistant to the atmospheric influence of the climatic environment.

Additionally, wooden elements are covered with fire-fighting agents. The general scheme for installing a roof truss system:

• arrangement of the frame;
• installation of rafters.

The truss roof structure is tightly and securely fixed. Then stepped recesses of the walls are mounted. After that, work on thermal insulation and waterproofing of the roof is carried out. After their completion, they begin to install the crate and lay the selected roofing. Then mortise or dormer skylights are installed and internal and external finishing works are carried out.

Building a house with a mansard roof

Stages of installation of the truss frame

1. The top beam is laid. All elements are fastened with staples and tied with steel. This will be the rafter frame.
2. Mauerlat installation. It is this system that is the main one for the entire roof of the attic. Boards 50 mm thick and bars 100x150 mm are used. Along the perimeter of the walls, a beam is strengthened and sheathed with a board, additionally tied with steel.
3. A layer of waterproofing is laid under the bars.
4. Rafter legs are raised. Marks are applied to the Mauerlat in increments of 15 cm and the bars are nailed.
5. Edge rafter legs are attached to the pediment. It is very important at this stage that the edge of the rafters make a straight line.
6. A level rope is attached to the rafters and the remaining rafters are installed.
8. The straps are joined together. A ridge beam is attached.

The rafter roofing system is completed. It remains to equip the crate, lay a hydro-barrier and insulation. The roof has been installed. Installation of the roof truss systemhttps://www.youtube.com/watch?v=gm9xv9JLozQ

Stages of drawing up a project drawing

The drawing of the roof for the attic begins with the choice of its shape, and the definition of the section of the rafters and the installation step.

1. To determine the size of the rafter legs, the following parameters are taken into account:

• slope angle;
• roofing material;
• climatic features of the area in which construction is underway.

1. The next step is to determine the number of rafters. According to the design of the truss roof, it can be both inclined and hanging. Before designing, you must select the type of structure.
2. Calculation of the roof sheathing. Allocate:

• continuous bituminous roll covering;
• ordinary sheet (wavy) coating.

1. The number of parts for fastening, other auxiliary thrust elements is calculated.

Mansard roof with layered and hanging rafters, with the removal of the bottom of the rafters beyond the wall

The drawing should include not only the visual performance of the roof structure, but also contain the following data:

• joining the roof with the parapet with a clamping profile;
• joining the roof with a parapet without a clamping profile;
• slope docking scheme;
• mansard roof layout with a door opening;
• calculation of the number of wooden elements of building materials and the amount of roofing;
• gutter equipment and snow-retaining elements.

Important! If you align the angles of inclination of the upper and lower slopes of the mansard roof, then in appearance it will resemble the classic design of a gable roof. At the same time, the scheme of the load-bearing thrust structure itself will remain unchanged in the standard version, which is used for broken roof structures.

When drawing a broken mansard roof, it is necessary to carefully calculate the dimensions of all structural elements. It is also necessary to remember about the reliability, durability and safety of the roof in the operation of the house. Calculation scheme of the attic roof https://www.youtube.com/watch?v=RWu2HiFXGpM

Drawing Executors

Each house is individual. Therefore, the drawing of a broken roof structure is carried out individually, taking into account the peculiarities of the region. Of course, you can do a roof drawing yourself if you are one hundred percent sure of your own expertise. SNIP standards when drawing up a drawing of a roof project are used by many construction design organizations. This avoids accidents. That is why it is recommended to transfer the work of drawing up a drawing to specialist developers. Construction of a mansard multi-pitched roofhttps://www.youtube.com/watch?v=LxeBA1cIkIw

When building a private house, it is important to think through all the nuances that may arise in the process of work, as well as initially determine what the appearance of the finished building will be. This can be done using the services of an experienced designer. But at the stage of creating a drawing, not only the type of foundation and the area of ​​\u200b\u200bthe future house is determined, but also the type of roof that will be used. Remember that no house will last long, and living in it will never be comfortable, unless you carefully plan and equip the roof. Before starting work on creating a roof, it is necessary to design it, as well as calculate the area of ​​\u200b\u200bthe structure. Experts in the construction industry argue that if you correctly approach this issue, the arrangement of the roof will not only be quick, but will also make installation work much easier and cheaper. It is extremely important to determine correctly the main elements of the section, so that during the implementation of the project it would not be necessary to make any adjustments and edits, redoing everything anew.

After developing the scheme, it is necessary to determine the most acceptable material that will be used to create the roof of the building. Do not forget that this range of work is strictly regulated by the regulatory requirements of the current standards. In this article, we will look at everything you need to know when arranging a roof, as well as exactly how a flat roof plan should be created.

General information about the design of the project

The graphical part of the calculations must necessarily visualize the entire range of work performed. The customer is provided with a flat roof roofing plan, a design drawing, certification, as well as other necessary documentation, if it is necessary for the implementation of the project. Today, a roofing scheme must be created if the building is equipped with an external drain. If you decide to give preference to the internal type, and the building itself is not capital, then you can refuse to create a technical drawing. Thanks to the view of the house from above, it is easy to determine the geometric characteristics of the floor, the installation features of the installation of load-bearing structures, as well as other components of the object.

As an addition to the drawings, there is a diagram of the arrangement of the gable, which clearly lists the design parameters. If the project requires cutting sheets, it is important to provide information about this. Particularly responsibly, one should approach the creation of drawings of a pitched roof, which make it possible to visualize the dimensions of the sheets, as well as the consumption of the material to be used.

Benefits of a flat roof

Of course, all people who decide to take on the construction of their own home often face the problem of choosing the most optimal type of roof. It is safe to say that the use of a flat roof in a building project will make the appearance of the finished house really stylish and modern. In addition, this type of design is easy to install and is considered a budget option. But do not forget about one significant drawback of this roof, which is that it is highly susceptible to the influence of environmental factors and needs thorough waterproofing work.

What you need to know about flat roofing

Below we list the main requirements that are put forward for this type of structure, namely:

Since precipitation should in no case accumulate on the roof surface, there should still be a slope. To ensure the durability of the structure and the reliability of the roof itself, it must be no less than 2%. The best option is 10-15 degrees.

If your area is characterized by prolonged and heavy rains or a large amount of precipitation in the cold season, then in this case only one slope is not enough. It is important to consider the creation of a complete drainage system. It can be both external and internal. One riser is able to serve a plot of about 150-200 square meters.
In suburban housing construction, often external drains are created using special overflow windows, which are equipped at the level of the roof storm water inlet. If the drain lines do not intersect, it is strongly recommended to display the perimeter of the facade in the roof plan.

It is important to note that the projects of private cottages often do not contain information about the angle of inclination, in which case, to correct the designer's mistake, you do not need to redo all the work again, but you just need to form a slope using various bulk materials, as well as screeds or slabs from polystyrene.

The subtleties of preparing a pitched roof plan

To begin with, it is worth noting that a pitched roof is a roof that is a prefabricated structure of sheets with a slope of no more than 10%. Given the design features, construction experts distinguish two types of roofing - with or without an attic. The most common and popular option is a roof consisting of 2 slopes. This design can be applied to any structure. In the context, it resembles a triangle, and the finished scheme should contain detailed information about such indicators as: the length, the location of each of the elements, as well as the section. It is extremely important during the design process to determine the principle of fixing the nodes, as well as fix this in the regulatory and technical documentation for the facility.

in this case, the arrow is made with main lines 2 ... 4 mm long, drawn at an angle of 45 ° to the extension line. Marks are located to the left of the facade along one vertical line; the shelf above which the numerical value of the mark is placed must be turned away from the image.

9. Circle the facade with solid thin lines; draw the ground level line with a solid main line and bring it beyond the contours of the facade by 15 ... 20 mm.

10. Above the completed facade, write the name of the image, in which you indicate the extreme axes, for example "FACADE 1-9"

An example of the implementation of the facade is given in App. 4.6.

Plan rafters to execute in M ​​1:200

1. Apply coordinate axes:

Their designations.

distance between them.

Distance between extreme axes.

2. Draw the inner border of the outer wall, observing the binding.

3. To the outside of the coordinate axis, set aside the width of the eaves.

4. Along the perimeter of the building, we lay the mauerlat on the inner edge of the outer wall.

5. In the corners of the building, we install crossbars to support the diagonal rafter legs.

6. From the corners of the building at an angle of 45 ° we draw diagonal rafter legs.

7. On the inner walls we lay the lower run (lying) above them we lay the lower run.

8. We lay out the rafter legs, starting from the support node through 1200-2000 mm, resting them on the Mauerlat at one end.

9. We install the racks starting from the support node, after 3-6 m.

10 We lay the shortened rafter legs in a checkerboard pattern along the diagonal rafter legs.

11. For the device of the cornice to each rafter leg and ... we attach the filly, and to the diagonal rafter legs on both sides.

On the plan of the rafters, with a dotted line, we depict ventilation and a frame for dormer windows.

Figure 10 - Plan of the rafters

An example of a rafter scheme is given in App. 4.7.

Roof plan to be executed in M ​​1:200

Pitched roof plan:

2. Use thin dashed lines to draw the outer edge of the outer walls, observing their binding to the axes.

3. Show the lines of the roof cuts (slopes), observing the amount of overhang (overhang) of the eaves.

4. Show the lines of the sloping ribs (at an angle of 45 °) and valleys, the line of the roof ridge.

5. Depict dormer windows that serve to exit to the roof, to illuminate and ventilate the attic.

6. Draw ventilation pipes in projection connection with the floor plan.

7. Depict, if required, a roof fence around the perimeter. The fence is installed for the safety of repair work and cleaning the roof from snow. The height of the fence is not less than 0.6 m. The fences on the roof should be provided for:

In buildings with a roof slope of up to 12% inclusive, the height from ground level to the cornice (parapet) is more than 10 m;

In buildings with a roof slope of more than 12% with a height of more than 7 m;

For exploitable flat roofs, regardless of the height of the building.

Fences are made of round or strip steel in the form of welded gratings, fixed on steel racks with braces. Steel racks and struts are installed on top of the roof and nailed to the roof sheathing. Under the legs of the racks and struts for reliable waterproofing, special gaskets made of sheet rubber are placed.

8. An external organized drainage system should be designed and gutters and downspouts should be depicted on the roof plan. The distance between the external drainpipes should be taken no more than 24 m; the cross-sectional area of ​​​​the drainpipe should be taken at the rate of 1.5 cm 2 per 1 m 2 of the roof area (SNB 5.08.01-2000. Roofs).

Calculate the number of downpipes. Specify the diameter of the downpipe D, for example D= 13 cm.

Find the cross-sectional area of ​​the pipe S pipes according to the formulas:

S pipes = πR 2

or S pipes \u003d πD 2 / 4, if the pipe is round,

S pipes \u003d 3.14 × 13 2 / 4 \u003d 132.665 ~ 133 cm 2

It is possible to accept pipes and rectangular cross-section. Calculate the area of ​​the roof S roofs.

Calculate how much roof area one downpipe will serve:

1.5 cm 2 pipes - 1m 2 roofs,

133 cm 2 pipes - X m 2 roofs,

X \u003d 133 / 1.5 \u003d 88 m 2.

Number of drainpipes:

N pipes = S roofs /88.

Place this number of drainpipes evenly around the perimeter of the roof in characteristic places; draw them on the plan, tie the axes to the coordinating axes.

The decision on what will be the gutters (wall or suspended), make your own.

Flat roof plan:

1. Apply the coordination axes, their designations, the distances between them and between the extreme axes.

2. Depict the parapet of the outer walls, the parapet of the wall at the place of the height difference of the building.

3. Draw ventilation pipes in projection connection with the floor plan.

4. Draw a shaft for access to the roof.

5. Depict, if necessary, fire escapes.

On each section of the roof, limited by walls, there must be at least two water intake funnels. Number of funnels N take on the basis that one funnel serves at least 800 m 2 of the roof:

N=S roofing /800.

If the area of ​​the non-exploited roof plot is less than 700 m 2, and the roof with landscaping is less than 500 m 2, it is allowed to install one funnel with a diameter of at least 100 mm (SNB 5.08.01-2000).

7. Place the funnels on the roof surface in such a way that the storm sewer risers pass through the auxiliary premises of the building (stairwells, bathrooms, vestibules, corridors, etc.). In the thickness of the walls, the installation of downpipes is not allowed. Draw funnels in circles, tie their axes to the nearest coordination axes of the building.

The erection of the roof is one of the most important stages of construction. The durability of the building itself and the level of comfort of living in it directly depend on the reliability of the "umbrella" from above, on its resistance to precipitation and any external influences.

Of all the variety of roof structures, gable can be attributed to the most popular, simply because of the relative simplicity of its construction. However, behind this "simplicity" lies a lot of different nuances, the need to carry out certain calculations and follow technological rules. However, this publication has the main task: to show that the installation of gable roof rafters with your own hands is a completely doable task, even for a novice builder.

Let's go through all the steps of the rafter installation process for such a roof together, from the basics of preliminary design to an example of practical implementation.

General arrangement of a gable roof

Basic concepts

Structural elements of the gable roof truss system

Let's make a reservation right away that this scheme, of course, cannot reflect the entire possible variety of designs, but the main parts and assemblies on it are shown quite clearly.

1 - Mauerlat. This is a board or beam that is rigidly attached to the upper end of the external load-bearing walls of the building. Its purpose is to evenly distribute the load from the entire roof system to the walls of the house, creating conditions for reliable fastening of the rafter legs at their lower fulcrum.

2 - rafter legs installed in pairs. They become the main load-bearing parts of the entire roof system - it is the rafters that set the steepness of the slopes, will be the basis for attaching the batten, roofing, and if the roof is planned to be insulated, then the entire thermal insulation "pie".

For the manufacture of rafter legs, high-quality boards or timber are used, and round timber can also be used. About the section of lumber, which will be sufficient to ensure that all possible loads can be guaranteed, will be discussed below.

The rafters may end on the Mauerlat, but more often they go beyond the perimeter of the walls of the house, forming a cornice overhang. However, lighter parts can also be used for this - the so-called "fillies", with which the rafter legs are increased to the required width of the overhang.

3 - skating run. It can be a beam, a board or even a composite structure. The run runs along the entire line of the ridge and serves to securely connect the upper points of paired rafter legs, connect all rafter pairs in order to impart overall rigidity to the entire roof structure. In various roof options, this run can be rigidly supported by racks, or tied only to the connection node of the rafter legs.

4 - puffs (contractions, crossbars). Horizontal details of the reinforcement of the system, additionally connecting paired rafter legs to each other. Several puffs located at different heights can be used.

5 - floor beams, which will serve as the basis for mounting the floor in the attic and the ceiling from the side of the room.

6 - and this beam simultaneously plays the role of a bed. This is a beam that runs along the entire length of the roof, which is a support for installing additional reinforcement parts for the truss system. The bed can be installed as shown in the figure (like a floor beam), or it can be rigidly laid on a main partition inside the building.

7 - racks (headstock) - additional vertical supports of the rafter legs, preventing their deflection under the influence of external loads. Racks at the top can rest against the rafters themselves, or against an additional run, longitudinally connecting the rafter legs at a certain height.

8 - braces. Often, with a large length of the rafter legs, their bearing capacity is not enough, and reinforcement only with racks does not provide the necessary strength. In these cases, diagonal reinforcing elements are used, resting on the bed from below, creating an additional point of support for the rafters. The number of struts and the place of their installation can vary in roofs of varying degrees of complexity.

Some differences between hanging and sloping gable roof systems

Gable roofs can be divided into two types of structures - with layered and hanging rafters. In addition, combined systems are widely used, in which both principles of construction are combined. What is the fundamental difference?

Laminated rafter system

This design of the truss system is characterized by the presence of support on the internal capital partition in the building. On the upper end of this partition, a bed is mounted, on which drains are supported, supporting the ridge run. Thus, the rafter legs are “leaned” on a vertical support, which makes the entire system as strong as possible.

This scheme is the most popular because of its reliability and relative ease of implementation. If it is possible to create an additional point of support in the center, then why not take advantage of this? True, if it is planned to place a living space in the attic, then vertical racks can sometimes become a hindrance. However, their presence is also sometimes “beaten up”, using, for example, an internal light partition for mounting.

Depending on the number and placement of internal partitions, the design of the layered truss system may vary. Some examples are shown in the illustration below:

Fragment “a” shows the simplest option, which, by the way, on short rafter lengths (up to 5 meters) may not even have struts shown - a row of central racks under the ridge run is enough

With an increase in the width of the building, the system naturally becomes more complicated, and additional reinforcing elements appear - puffs and struts (fragment "b").

Fragment "c" clearly demonstrates that the internal main wall does not have to be located exactly in the center, under the ridge. It is also possible such an option, as shown in the illustration, but with the condition that the displacement of the bed relative to the ridge does not exceed one meter.

Finally, fragment "d" shows how the rafter system can be supported in a large building, but with two main partitions inside. The distance between such parallel beds can reach up to a third of the width of the building.

Hanging rafter system

Graphically, this roof scheme can be depicted something like this:

It immediately catches the eye that the rafters rest only on the lower part, and then are connected to each other on the ridge. There is no additional support in the center, that is, the rafter legs seem to “hang”, which predetermines the name of such a system. This feature imposes certain restrictions on the use of hanging rafters - usually such a scheme is practiced with a distance between the bearing walls on which the Mauerlat is fixed, no more than 7 meters. Installed puffs only partially relieve the load from the external walls.

The illustration below shows several options for a hanging system. However, some of them already, rather, can be classified as combined.

Fragment "d" - hanging rafters are interconnected by a screed at the level of the Mauerlat or fixed to a powerful floor beam, forming a triangle with it. There are no other reinforcing parts. A similar scheme is permissible with a distance between walls of up to 6 meters.

Option "g" - for the same size house (up to 6 meters). The puff (bolt) in this case is shifted upwards, and is often used for filing the ceiling of the attic.

Options "e" and "h" are designed for a span between walls up to 9 meters. Multiple puffs may be used (or top puff in combination with bottom floor beam). Another approach is to install racks under the ridge run, by analogy with a layered system. Only as a lower point of support, it is not a bed on the main partition that is used, but the racks are supported by a puff or a floor beam. To call such an option purely “hanging” is already difficult, since here is clearly a combination of parts from both designs.

To an even greater extent, such a combination of two schemes is expressed in the "and" variant, which is designed for large spans, from 9 to 14 meters. Here, in addition to the headstock, diagonal struts are also involved. Often, such trusses are generally assembled on the ground, and only then they are lifted and set in place, connected to each other, thereby forming the entire roof frame.

So, in preparation for the construction of a gable roof, it is necessary to study the principles of the device of a particular system, evaluate their advantages and disadvantages, choose the best one for your conditions and draw up a graphic working diagram. It will be needed both when purchasing the necessary material, and for the production of the installation work itself. However, drawing up a drawing should still be preceded by some calculations.

Calculation of the basic parameters of the gable roof truss system

Let's take another look at the concept of a gable roof device to highlight those parameters that need to be calculated.

So, in the process of calculation, we need to decide on the following values.

The initial data is the length of the side of the house along the gable part (highlighted in blue - F), and the length of the house along the ridge (purple - D). It is assumed that the owners have already decided on the type of roofing in advance - since there will be certain restrictions on the steepness of the roof slopes. (angle a).

• The height of the ridge above the plane of the Mauerlat (H - green), or, conversely, determine the angle of the slope, starting from the planned height of the ridge.
• The length of the rafter leg (blue color - L), and, if necessary, the extension of the rafter to form a cornice overhang of the required width (l).
• Calculate the total loads that fall on the truss system in order to determine the optimal section of lumber for the manufacture of rafters, their installation step (red - S) and the allowable span length between the support points. All these parameters are closely interconnected.
• When these calculated values ​​\u200b\u200bare on hand, it is already easy to draw up a graphic diagram, determine the need and optimal arrangement of reinforcement elements, and calculate the amount of material for their manufacture.

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We calculate the steepness of the slope and the height of the ridge

The slope angle of the slopes can be determined by the owners according to various evaluation criteria:

• For purely aesthetic reasons - when the appearance of the building becomes "at the forefront". Many people like roofs with a high ridge, but at the same time, one must not forget that the wind load increases sharply on such a roof. Yes, and materials for the manufacture of a high roof will go immeasurably more. At the same time, on steep slopes, the snow load is reduced to almost zero - it is possible that for "snowy" regions this assessment parameter may become decisive.
• For reasons of useful use of the attic space. With a gable roof scheme, in order to achieve the maximum attic area, it is necessary to build slopes with a very steep slope, that is, with the same consequences as mentioned above.

• Finally, there may be a completely opposite approach - for reasons of economy, make a roof structure with a minimum height in the ridge. But in this case, you will have to focus on the minimum allowable slope angles for a particular type of roofing. To reduce the steepness below the indicators recommended by the manufacturer is to “plant a bomb” in your roof, both for reasons of its strength and durability, and from the standpoint of the waterproofing qualities of the coating.

It is not difficult to calculate the height of the ridge above the floor plane (Mauerlat). At the heart of the vast majority of nodes of any roofing system is a triangle, which, in turn, obeys strict geometric (more precisely, trigonometric) laws.

So, in our case, the width of the roof along the gable line is known. If the roof is symmetrical, then the ridge will be located exactly in the middle, and for calculations, you can simply divide the width F by two (the base of the triangle f=F/2). With asymmetrical slopes, you will have to project the top of the ridge onto line F, and measure the distances f1 and f2 from it to the edge of the triangle (to the Mauerlat) on each side. Naturally, in this case, the slope of the slopes will be different.

H =f × tga

In order not to force the reader to look for the values ​​​​of tangents and carry out calculations manually, a calculator is placed below, in which the necessary tabular values ​​\u200b\u200bare already entered.

1) Apply the coordination axes of the building.

2) Draw the outline of the walls.

3) Lay a Mauerlat on the outer walls along the perimeter of the building.

4) In the corners of the building, lay a support crossbar to support the diagonal rafter legs.

5) At an angle of 45 °, draw diagonal rafter legs from the corners of the building.

6) Lay a bed along the inner wall of the building and show the upper run.

7) Lay the rafter legs, starting from the support node, after a certain distance.

8) On the diagonal rafter legs, lay short rafter legs (spreaders) in a checkerboard pattern.

9) Install the racks at intervals of 3000 - 6000 mm, starting from the support node.

10) With a building width of more than 12 m, lay a crossbar to the rafter legs.

11) To form a cornice, a filly is nailed to each rafter leg, and fillies, called shorties, are nailed to the diagonal rafter legs on both sides.

An effective solution for the roof device is the use of layered rafters to cover spans up to 14 m with one internal support in the building and up to 16 m with two internal supports.

The rafters are connected using fixing bolts, staples or nails.

In the event that the distance between the supports (external or internal) is more than 7500 mm, in civil buildings the supporting foundation of the roof is roof trusses, representing a flat geometrically unchanging lattice system, consisting of separate interconnected elements (rods). Roof trusses can be wooden, metal-wooden, steel and reinforced concrete. Wooden farms are called hanging rafters.

The step of roof trusses with spans up to 9 m is 3-4 m, with spans over 10 m - 1.5-2 m.

Hanging rafter schemes

Dormer windows arrange in pitched roofs for lighting, ventilation of the attic, exit through them to the roof. They can be semicircular, triangular, rectangular. Lighting - through the glazed sash of the binding with a size of at least 0.6 × 0.8 m. For ventilation, wooden louvered grilles are used, located adjacent to the glazed sash of the dormer window. Dormer windows must be placed so that through ventilation is ensured. It is recommended to place the bottom of the window no higher than 0.8 - 1.0 m from the top of the attic.

Types of dormer windows

a - triangular; b - semicircular; c - rectangular; d - polygonal

1 - glazed parapet; 2 - louvre

A four-pitched roof, provided that it is properly erected, is distinguished not only by its presentable appearance, but also by its increased strength, which allows it to effectively withstand precipitation and strong winds. In this article, we will talk about what the device of the truss roof system of a hipped roof is, consider the varieties of such frames, and also describe a detailed work plan for their construction.

Comparative characteristics of frame types: tent and hip

The category of roof with four slopes includes 2 types of frame systems, which schematically look like square (hipped roof) and rectangular (hip roof) envelopes. In our country, the roof envelope is quite popular. The main feature of hipped roofs is the absence of gables. For the construction of the truss system of a hipped roof, in both cases, hanging and layered rafters are used. Their assembly methods are standard for roofs with any number of slopes.

Distinctive features of hipped roofs of various designs:

• In the case of a hipped frame, the roof consists of four isosceles triangles that touch at the vertices at one point. In this case, the functions of the ridge are assigned to the central support beam in layered structures, or to the upper point of the hanging truss truss.
• The hip-type roof assumes the presence of two triangular and two slopes in the form of a trapezoid. In this case, trapezoidal slopes are adjacent to the ridge beam with upper ribs, and triangular - with vertices. In this case, all four slopes are in contact with each other with lateral ribs.

Studying the plan of the truss system of a hipped roof, we can conclude that the choice of configuration of a hipped roof depends on the shape of the building. That is, square houses are covered with tent structures, and rectangular houses with hip roofs. In this case, you can use any roofing materials, both hard and soft.

When drawing up the drawings of the truss system of a hipped roof, the geometric shape should be clearly indicated, as well as the position of individual elements and projections of slopes with exact dimensions.

As a rule, hip and hip-type rafter systems are combined with traditional single-pitched, gable and sloping roofs within one object.

To support a four-pitched structure, you can use a Mauerlat, which is the upper trim on concrete or brick walls, as well as the upper crown of a log cabin. Layered technology is used in cases where it is possible to install an upper and lower support under each rafter leg.

• Mauerlat must be fixed with reinforcement in order to withstand bursting forces in the event of rigid fixation of the rafter legs with wooden plates or metal corners.
• If the upper part of the leg is fixed rigidly, and the lower part is hinged, the Mauerlat can be fixed in the usual way. In this case, with increased loads on the frame, the rafters will be able to move slightly.
• The bursting load and pressure on the Mauerlat will be leveled when using rigid fasteners on the lower part of the rafters and hinged ones on the upper heels.

Please note that the method of laying the mauerlat and the entire truss system should be provided for at the design stage of the building. In the absence of internal load-bearing walls and the impossibility of placing supporting elements for the central part of the roof, the technology of hanging rafters is used. However, most often, an inclined type of a stable frame is still installed, having provided in advance for the presence of load-bearing structures.

During the construction of hip and hip frames, such specific nodes of the truss system of a hipped roof are used:

• Diagonal legs from which the ridges of the slopes are made. In tent-type frames, such slanting legs combine the corners of the roof with its upper point. Hip frames involve joining the consoles of the ridge beam with the corners by means of diagonal rafters.
• Sprockets (semi-legs) - elements mounted at an angle of 90 degrees to the cornices. Since they are joined with diagonal rafters and are parallel to each other, their length will differ. Roof slopes are created from such elements.

The same structural elements are used to create valleys, with the only difference being that the corners are made concave.

It is the installation of slanted rafters that is the most difficult. Moreover, these elements will have an increased load, since they serve as a supporting element for fastening in the upper part of the sprigs, that is, they perform the functions of a skate. Therefore, before starting work, it is necessary to calculate the truss system of a hipped roof.

In general, the process of erecting a roof with four slopes includes the following steps:

1. Laying Mauerlat on brick or concrete walls. In log houses, this element is the upper crown.
2. Installation of a central support beam under a hipped frame or assembly of supporting structures for a hip roof.
3. Installation of layered rafter legs for a particular design.
4. Fastening diagonal rafters that align the corners of the roof with the central top or ends of the ridge.
5. Marking and installation of sprockets.

If a hanging type of truss system is assumed, then the first step in creating a tented structure will be the placement of a central truss in the shape of a triangle. When creating a hip-type structure, several truss trusses are attached at the initial stage.

hip roof construction

Since in private construction mainly hip roofs with layered rafters are used, we will consider in more detail the installation process of a four-pitched truss system of this design. The support for the structures will be floors placed on the Mauerlat.

Fixing by cutting will be carried out only at the junction of the ridge with the rafters, so the Mauerlat can be installed on conventional mounts. In the building under consideration, the box of the house has dimensions of 8.4 × 10.8 m. The roof on the plan will exceed the dimensions of the house by 40-50 cm on each side - this is the width of the cornice overhang.

Plan for laying supports on the Mauerlat

Depending on the material used to build the walls of the building, the Mauerlat can be laid in various ways.

• In the upper part of the walls of gas silicate or foam concrete blocks, it is necessary to pour a reinforced concrete belt in which to place anchors for the subsequent fixation of the Mauerlat.
• When constructing brick walls in their upper part, a side of 1-2 bricks is made in such a way that a depression for a wooden frame is formed in the center of the wall. As the masonry progresses, wooden plugs are placed between the bricks, to which the mauerlat will be fixed with brackets.

For Mauerlat you will need a bar with a section of 100 × 150 or 150 × 150 mm. When planning the use of space under the roof, thicker beams should be used. The elements of the frame are joined with oblique cuts, followed by reinforcement with nails, capercaillie or self-tapping screws, and in the corners with staples.

Next, you need to place overlap elements on the Mauerlat. They are made from bars with a section of 100 × 200 mm. The central beam is laid first. If the length of the lumber is not enough, it is made from two pieces of timber. Moreover, the junction should fall on the supporting element, for example, a load-bearing wall.

In this case, the beams are laid in 60 cm increments. As a rule, the box is not ideal, so the spacing between the beams can be slightly adjusted to smooth out imperfections. The indent from the walls of the house to the extreme beams located on both sides should be 90 cm. It is required for the installation of extensions.

Extensions are attached to the end parts of the floor beams. For convenience, at first they are placed only in those places where the rafters will be installed later. They are attached to the surface of the Mauerlat with nails, and to the beams - with dowels, large-section nails, self-tapping screws, after which the fastening is reinforced with corners.

Assembling the ridge section of the hipped roof

The central segment of the hip-type roof is nothing more than a traditional gable design. Therefore, its assembly is carried out according to the technology for pitched roofs. Although such a design usually provides for the presence of a bed on which supports are placed under the ridge, in this example, the functions of such an element are assigned to the central floor beam.

The ridge section of the roof is performed as follows:

• First, a support structure is assembled under the rafters, which will rest against the ridge beam with their upper heels. The ridge itself will be supported by three supporting pillars, of which the middle one is mounted directly on the central floor beam. In order to correctly install the two extreme pillars, transverse bars are placed under them on top of the ceiling, covering at least 5 beams in length. Struts provide additional structural stability. The supporting elements of the frame are made of timber with a section of 100 × 150 mm, and the struts are made of boards of 50 × 150 mm.
• To ensure that all rafters are the same, a template is made for cutting them. To do this, a board of the required length is tried on at the installation site, the cuts are marked, after which all the rafters are cut along it.
• The finished rafters are supported on the ridge beam by the cutting place, and the lower part is fixed on the take-out.

Usually, floor beams are placed perpendicular to the box so that the emphasis of the rafter legs in the central part of the roof falls on them. Since in this example the rafters are joined to the extension, additional supports must be installed. They are placed in such a way as to redistribute the load from the rafters and supports to the walls.

At the end, you need to install three rows of extensions on each side. After that, a cornice is attached to the floor beams and extensions strictly horizontally, facilitating further work with the roof.

Fastening the corner extensions of the truss system

In the corners behind the cornice board, it is necessary to install corner offsets.

They are attached like this:

• From the corner to the place of the conditional intersection of the floor beam with the extreme support of the frame, a cord is pulled.
• A bar is placed along its contour in the right place. On the bar, it is necessary to mark the places where it intersects the floor beam and the corner joint of the eaves. According to the markup, all excess is cut off.
• With the help of corners, the finished element is attached to the ceiling and the Mauerlat.

The same actions are performed with all the remaining offsets.

Roof rafters - drawings

The diameter of the diagonal rafters coincides with the dimensions of ordinary elements. Since in our example the slope of the trapezoidal slopes and hips is different, one of the slanting legs is placed slightly higher than the other.

The process of creating and installing braids is as follows:

• With the help of laces, we outline additional lines for marking the gash, pulling it to the corners and the center of the ramp from the top point of the ridge beam.
• Determine the angle between the top of the corner stem and the lace. This will be the angle for the bottom cut (α). The upper gash (β) is calculated by the formula: β=90º-α.
• We take a piece of board and cut one edge in it at an angle β. Having attached the workpiece to the place of joining the upper parts, we combine its edge with the lace. We mark the excess and saw off.
• In another blank for the lower heel, we saw off a section at an angle α.
• Using the templates obtained, the first diagonal rafter is cut out. If there is no whole board of the required length, the element is assembled from two pieces. They are spliced ​​using an inch board, 1 m long, placing it on the outside of the rafters. The finished item can be installed.
• Similarly, the second half of the diagonal rafters is made, not forgetting that it should be placed slightly lower than the first. The place of joining of the two halves of the sloping should not coincide with the segment of the splicing of the boards into one piece.
• Docking boards is made with nails at a distance of 40-50 cm.
• Next, along the lace on the rafter, you need to draw a gash line so that it can be docked with an adjacent diagonal element.

The manufacture of the remaining 3 parts is carried out in a similar way. Under each of these rafters, in places where beams with corner offsets are joined, supports are installed. Additional supports near the ridge are required if the span exceeds 7.5 m.

Assembly and installation of hip rafter legs

On a stretched lace from the ridge to the center of the slope, we measure the lower angle γ and calculate the opposite angle δ=90º-γ. Just as with diagonal parts, cut-out templates are made on the upper and lower heel of the element so that it fits snugly between the diagonal rafters. Having made the central rafter of the hip, it must be installed in the appropriate place.

Rigidity of the structure and reliable fastening of the shortest sprigs is ensured by installing short protrusions between the eaves and corner protrusions.

At the next stage, templates for sparrows are made:

• A piece of board is sawn off at an angle δ and tried on at the junction with a diagonal leg.
• Extra sections are distinguished, then they are sawed off. This template will be needed to create all the sprigs that will be installed on one side of the hip. For the other half, washed down on the blanks will need to be done from the opposite side.
• The lower heel of the sprigs is cut according to a template sawn off at an angle γ. Such a blank is suitable for creating lower joints on all sprigs.

The manufacture of sprigs is carried out taking into account the estimated length of the elements and according to the manufactured templates. They will fill the plane of the hips and the main slopes. The installation of these parts is carried out in such a way that the joints of the braids with the sprigs from opposite sides do not converge in one place, that is, apart. Corners serve as fasteners for connecting splints with diagonal rafters, and jagged plates or corners with outriggers and floor beams - whichever is more convenient.

The construction of a roof with a hipped type of frame is carried out using the same technologies as with a hip one. The only difference is the absence of a ridge in hipped roofs. In this case, the installation of the hipped roof truss system begins with the joining of the diagonal rafters, and then the rafters. If hanging rafters are used, the central truss is installed first.

Thus, a detailed study of the features of the construction of hipped roofs will allow you to start creating a frame structure with skill.