What are roof trusses? In every house, the roof plays an important role, which crowns it and protects it from the weather. The roof truss is a frame – the skeleton of the roof, usually made of wood. Its task is to transfer the load from the roofing, the load of its own weight, snow or wind, as well as between the individual truss elements by means of barbed connections. Rafter systems are the key elements of each roof truss.
The most important load-bearing element of the roof structure
Roof trusses are a prefabricated structure made of posts, beams and cross-braces, and after assembly they create a reliable foundation for the future roof. The roof trusses of single-family houses are mainly made of wood, which is exposed to the environment. In places where the wood is in contact with other materials, it is necessary to install gaskets that will serve as a moisture barrier from the roof side, a vapor barrier from the living quarters side. Remember to install ventilated gaps and treat the wood with flame retardants and antiseptics. The most optimal and reliable version of wooden roof trusses is triangular. It can withstand heavy loads and is most often used in private construction. It should be noted.
What is the characteristic of a wooden roof truss?
The most popular are wooden trusses, and their advantages include:
- Simplicity of manufacture and ease of installation
- Environmental safety
- Can be used in large spans (up to 18 meters)
- Ease of insulation installation
- Relatively low weight of the structure.
Installation of wooden trusses
When assembling the roof truss structure, reinforced metal corners are installed along the perimeter of the walls and ceilings. For reinforcement, special anchor nails are used for metal fasteners. In addition, the pre-assembled farms are positioned according to the level and connected to each other. The roof truss is the simplest type of roof truss, but also the least stable. There are two main types of roof truss structures: layered (rafter and beam), when a pair of rafters together with a wooden ceiling beam form a three-part structure resting on the outer walls of the building. And the beams that make up the wooden floor rest directly on the wall.
Hanging (truss with rafters resting on the walls), when the rafters are connected at the ridge and rest on the supporting walls, and the latter are attached to the crown. The truss consists of only two elements, and the overlap takes over the function of the third side of the triangle. The price of roof trusses varies depending on the province and the complexity of the roof and ranges from 52 to 70 per m2.
The girder roof truss is one of the most commonly used roof structures. It is relatively easy to manufacture and economical. It has a structure similar to the rafter system, but a horizontal element is added here – a girder – a structural part connecting and strengthening both rafters, usually located in the middle of the rafter’s length or slightly higher. There are two types of girder roof structures:
Wooden roof trusses are used in civil engineering for arranging sloping roofs in individual residential and auxiliary buildings. The design of the rafter system depends on the type of gable roof, the size and configuration of the building. High-quality workmanship and installation of the rafter system ensures the safety of the house and its reliable protection.
The basic elements of the structural triangle, giving rigidity to the entire structure, are: rafters, they form two sides of the structural triangle. When assembling the rafter system, the rafter legs are laid along the roof slope. The roof sheathing is fixed on rafter legs. Additional rigidity of wooden trusses is provided by auxiliary elements: support, struts, vertical stands.
Materials for trusses
Materials for the production of roof trusses are selected taking into account the purpose of the building and the loads they must withstand. Devices such as solar panels, water tanks or ventilation chambers can be mounted on a sloping roof, thus ensuring the strength of the truss elements through the proper selection of materials for their manufacture.
In the general case, the elements of the truss structure can be made of wood, rolled metal, reinforced concrete. In residential construction, wooden trusses are used, made of beams of various cross-sections, of boards. Wooden rafters impress with the simplicity of manufacture and assembly, the wooden elements are conveniently fitted in place, they can be easily hung or shortened and even folded. Installation of roof trusses during the construction of a private house is carried out at a height of 5 meters or more.
Important! Roof trusses are a structure that must always be made with high precision. This is the only way to ensure a solid foundation for the roof. Therefore, it is worth seeking help from professionals who are well aware of all the subtleties of creating such structures.