Suspended rafters, how to calculate and secure naslon

The roof structure is a complex system with support elements, a waterproofing coating, insulation and vapor insulation. All roofing units are exposed to temporary and permanent loads, so they must have a high bearing capacity to avoid deformation or even collapse of the roof. To ensure durability and long service life, an accurate calculation determines the composition of the frame, the distance between its elements, as well as their cross section. As a rule, in the private housing construction the napsled roof system is used, which allows to block structures up to 16 meters wide. In this article we will talk about its structure, features and main nodes.

Device and functions

A structure consisting of interconnected supporting elements supporting roof slopes is called a roof truss system. It performs the functions of a kind of frame, which gives the slope and shape of the roof. Installation of the roof structure is carried out only after the calculation of the loads that will affect it during operation. Correctly designed frame will solve the following problems:

1. Used as a base for fixing roofing material. Installation of waterproofing material on the surface of the slope perform on the crates of the roof frame, which evenly distributes the weight of the coating, and also gives it a rigid shape.
2. Forms the slope of the roof structure. The rafter legs of the frame are installed under a slope to the base, due to which the roof acquires a triangular shape. The inclined surface of the slope allows water and snow to slide freely without increasing the load on the elements of the supporting system.
3. Gives the structure rigidity and carrying capacity. The roof is subject to severe stress due to the large weight of the roofing, thermal insulation, the weight of the roof frame itself and the snow cap, so the roof system must have high strength properties and redirect the weight of the roof to the bearing pillars.

Note! The roof system of the naval type is called the roof supporting structure, which includes vertical pillars resting on the internal load-bearing walls. Installation of such a frame is carried out if in the middle of the house there is a capital wall installed on the foundation. A roof with a suspended truss system is subjected to bending stress only, due to which it does not require compensating expansion elements.

Composition

Before you install the roof, you must make an exact calculation of the loads that will affect it, as well as a detailed project. These simple calculations will help determine which elements will be included in the slant rafter system, calculate their cross-section and the distance between them. If the roof has a support on the internal load-bearing walls, then its frame consists of the following components:

• Mauerlata and lying down. These terms are called supporting elements of the roof structure, fixed on the upper tier of the walls, on which the roof slopes are supported. They are made of coniferous wood with a section of 100x100 mm or 150x150 mm. Lent is characterized in that it is mounted on the internal bearing partitions, and it can be fixed vertical posts supporting the ridge.
• The rafter. Suspended rafters are installed in pairs along the slope of the roof. Their peculiarity is that they have 2 points of support - on the mauerlat and on the ridge run. Due to this, the structure is durable and does not feel the stress on the burr. The step between the rafters, the thickness of the legs determines the calculation, taking into account the weight of the roofing and climatic conditions.
• Subrafter elements. Subrafter elements are called additional supporting elements, thanks to which the roof acquires a large bearing capacity. This category includes vertical supports, called drains, horizontal puffs, as well as struts supporting the rafters.
• Crates. The crate is mounted perpendicular to the rafter legs, and the roofing material is being installed on it. The calculation of loads determines whether the base of the roof should be solid or lattice.

Important! In designing a slant roof system, the main thing, before mounting, is to correctly calculate the permanent and temporary loads that a roof of a house is subjected to. Distinctive features of the frame of this type is the use of internal load-bearing walls for the installation of bilge, vertical construction, supporting the ridge structure.

Kinds

Roof twitches several types of loads, including the load on the expansion and bending. To compensate for these voltages, as well as to make the truss system stable and rigid, a large number of compensating elements are used, the cross section of which determines the calculation. To prevent deformations of the frame, the installation of the roof is carried out using movable mounts. Suspended rafters are of the following type:

1. Without a trace. The installation of the nacelle frameless nacelle frame is carried out with the help of movable fasteners, thanks to which, even after fixation, the system components can compensate for the load on the bearing walls. Suspended rafter legs of this type are fastened on one side with a hinge, and on the other with a slider.
2. Spacer. Expansional rafters of the nylon type have not two degrees of freedom, but one. One end of the leg in this case is fixed rigidly, and the other with a slider, hinge or other movable mount. Spacing truss frame provides for installation of the power plate, as it has a slight arching effect on the external bearing supports.

Experienced roofers to overlap wooden houses that have not yet completed the process of shrinking, use supportless truss frameworks, the movable supports of which can compensate for the deformations that occur with the gradual drying of wood. The calculation is that the non-fixed construction will settle together with the box at home.

Special features

The design of the glazing truss frame of the roof depends on many factors. The composition of the system is affected by the slope of the slopes, the climatic conditions in the construction zone, the selected roofing material. To take into account all these criteria, you need to perform the calculation of the loads on the roof. Depending on the width of the overlapping structure, the roof frame of the roof has the following features:

• To overlap structures up to 10 meters wide, a single bearing support on which vertical posts are mounted is sufficient. To compensate for the deflection of long truss legs, set the struts.
• To overlap structures up to 10–14 meters wide, one internal load-bearing wall is also enough. However, to strengthen the truss frame, consisting of a mauerlat, log, truss legs, trusses, racks and struts, use horizontal inhibitions that compensate for bursting load.
• To overlap a 16-meter-wide structure, 2 internal load-bearing walls are required. In this case, the roof frame consists of a mauerlat, log, rafters, struts, racks, bolts and tightening.

Keep in mind that the maximum length of the truss legs of the laminated frame is limited to the standard size of lumber, which is 6 meters. Of course, you can make razor rafters or put in fillies, but this design will be less durable.

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