During the construction of any building, various types of work are performed, and the correct implementation of each stage is the key to obtaining a high-quality result. So, during the construction of the roof, the installation of rafter systems occupies an important place. In this case, you need to take into account many points, such as calculating the step of the rafters, the angle of inclination, and so on.
Tent roof truss system
The tent-type roof is made with a four-slope rafter system, while all sides (hips) of the roof are isosceles triangles. The design consists of four hips, slightly differing in geometric shapes (the ends of the roof are triangles, and the transverse sides are made in the form of trapezoids).
Installation of rafter systems of this type is carried out using the following elements:
- Sloped (diagonal) rafters - these elements are sent to the corners of the building.
- Handicrafts - shortened load-bearing parts. They are attached at one end to the Mauerlat, and at the other to the mowing elements.
- Braces and racks.
- Crossbar (to strengthen the structure when spacer pressure occurs).
- Lezhin - a support for racks and struts.
- Sprengel - additional support for a long span.
- Run - a beam that is installed parallel to the Mauerlat (extreme support for rafters).
It should also be noted that there are two types of rafter systems for a tent roof, which differ in type of execution:
- Hanging design. Installation of rafter systems of this type is carried out in the absence of walls inside the structure.
- The layered system. This design is used in the presence of an average load-bearing partition, or columnar supports are provided at intervals when laying the foundation of a building made of reinforced concrete.
System calculation
Installation of rafter systems must be carried out with a preliminary calculation of structural elements. At the same time, the main points are highlighted:
- The step of the bars of the crate depends on what material the roof is made of: for metal tiles it is 35-40 cm, for sheets of steel - 25 cm, cement-sand tiles - 37.5 cm.
- The calculation of the length of the rafter legs and other mounting supports is carried out depending on the angle of the roof. This value is taken according to established standards (SNiP). It depends on the amount of precipitation, wind loads and the roofing materials used.
- The location and type of supports for diagonal rafters is provided depending on the size of the span. So, with a length of up to 7.5 m, struts or racks are carried out, which are attached to the upper part of the strut elements. And with a span of more than 9 m, sprengels and racks can also be used.
Installation procedure
Installation instructions for a rafter system of four slopes, if only the main points are highlighted, will have the following form:
- Installing the Mauerlat on the walls, when laying, a special recess can be provided or special fasteners are installed to protect against horizontal shift. Before that, you need to check the geometry of the walls.
- Installation of sloping rafters. This work begins with the opposite elements, they are attached to the Mauerlat using sprengels. At the same time, for high-quality connection, trimming is performed on rafters from two sides.
- Scaffolds are attached to the rafters through the tiled bars. Corner parts are parallel to the central elements.
- To increase the strength in the corners provide trusses with racks or install a transverse beam that connects the central rafters. It is attached with several racks.
Such work as installing the rafter system (the price will significantly decrease) can be done independently. Of course, for this it is necessary to have construction skills and some engineering knowledge.