A rafter is a part of a pitched roof support system that is not used in a single copy, but is used as a truss structure. This part consists of vertical racks, inclined rafter legs and inclined struts. If necessary, the rafters are reinforced at the bottom to the rafter beams.
What is a rafter
The rafter is the element that forms the basis of the whole system, it consists of inclined struts, inclined rafter legs and vertical racks. The support is carried out in wooden chopped buildings on the crowns. But if we are talking about frame buildings, then the support is made on the strapping from above, while in stone houses they are installed on the Mauerlat, which are bars with a maximum thickness of 160 mm. Mauerlat can be located along the length of the building or be located only under the rafter leg. In the case when the rafter leg has a section of insignificant width, the elements sag over time. In order to exclude this phenomenon, you should use a lattice that containsstruts, racks and crossbars.
For struts and crossbars, boards are used, the width of which can be 150 mm, while the thickness is 25 mm. To fix the rafter leg, a puff is used that connects the lower parts of the rafter legs. When sliding along the tightening, the end of the element may violate the integrity. In order to prevent slipping, the rafter leg must be strengthened with a puff by cutting. The rafters must be 400 mm from the edge.
Need to use
All of this is used to give the roof a quality of stability when exposed to high loads. As a result, the roof acquires the properties of reliability, and the rafters transfer the load from the weight of the entire system and snow to the internal supports of the building. If the building has small spans, then layered rafters should be used. If there are no intermediate supports, then a hanging rafter structure should be used.
Where rafters are used
Rafter is an element that is part of one large system for strengthening the roof. Depending on what design features the roof will have, different truss systems are used. In modern construction, certain requirements are imposed on rafters and roofing systems in general, among them:
- practicality;
- low installation and manufacturing costs;
- durability;
- strength;
- easy to install;
- functionality; aesthetics.
A rafter is an element that can be used in the construction of lean-to, double-pitched and sloping roofs. These elements are also present in the roof of Sudeikin. In the first case, rafters in the form of beams are used, their support is carried out on the walls, quite often this allows the roof to be exploited. The roof structure in this case must be pre-designed, only in this way it will be possible to distribute the load on the roof used. The rafter, the meaning of which is mentioned in the article, can also be used in a gable roof, in which case the system has triangular trusses, which are located at a certain angle. The legs should be on the Mauerlat, while they are additionally equipped with crossbars and stretch marks.
If there is a desire to leave space for arranging the attic, then a sloping roof should be made, the rafter system of which will be more complex. In this case, several types of rafters are used at once. It is worth noting that Sudeikin's roof design is very original and attractive. In this case, the rafters are interconnected, forming four triangular slopes. This system is suitable for square jobs.
What is a rafter in terms of design features
You can build the roof yourself. The rafters in its composition can be inclined. In this case, the upper node is fixed with a hinge, and the lower one with a floating connection. Such designs of rafters in the formprofile systems are usually called non-thrust. In this system, there is no transfer of load to the Mauerlat. The ridge connection is made as rigid as possible, the Mauerlat is supported by a hinge. In this case, pushing forces are transferred to the walls. This system, which combines hanging and layered rafters, is also called a hybrid. Load redistribution is the basic principle of this system. The weight of the roof is taken by the rafters, which are butt-jointed and work in bending. At the same time, the ridge beam is not such an indispensable element, since it is almost inactive.
For reference
The spacer rafters, the photos of which are presented in the article, should be equipped taking into account the quality of the bolted connections. Beforehand, holes should be drilled in the products, the diameter of which should be one millimeter smaller than the diameter of the bolt or stud. If they are too large, then during the work the Mauerlat may be damaged.
Material selection
The word rafter is known today to every builder, but not every home master is familiar with what is the best material to use for the manufacture of these elements in the roof structure. The basis may be wood, monolithic reinforced concrete structures or metal. The latter are galvanized or steel, in the first case it is possible to obtain lightweight structures. When choosing a material, experts advise paying attention to the purpose of the building. At the same time, there must bethe expected loads on the roof are also taken into account. Wooden rafters are used most often; for this, high-quality glued beams or solid wood are selected. For work, you will need not only lumber, but also carpentry tools, as well as fasteners. If you decide to use glued laminated timber, then it should have a width ranging from 12 to 18 m, but solid logs and boards can have any design.
