From the climatic zones in which your personal home is located and from which types of building materials it is built, the shape of the entire roof, options and methods of attaching the rafters should be chosen. This is considered the main part of the system that holds the entire roof.
Diagram of the roof truss system.
Roof overlapping is a complex process that is carried out according to special rules. For example, fixing rafters to floor beams is done in several different ways:
Installation of all elements is carried out according to special rules. Let's start with the fact that there are 2 types of fixed bars:
Fastening the rafters to the floor beams is a complex process that requires special attention. Hanging bars usually have only one point of support - this is the wall of the house. As a consequence, there is a horizontal spacer pressure throughout the truss system.
Figure 1. Connection diagram of rafters with a tooth and a spike.
In order to reduce it, use a bar or board. This is the so-called tightening. They connect the feet of each counter rafters of the ceiling together. Thus constructed indistinct triangle adjacent to the wall of the house. It happens that the puffs are replaced by the bars of the floors installed perpendicular to the walls.
Such rigid attachment of rafters to beams is often used in the construction of penthouses. It is important to note that it is better to use such a mount if you are sure that the walls of the house you are building are strong enough and will withstand all the point gravity from the rafter bars.
When connecting wooden rafters for lightweight roofs, as a rule, slabs of overlap are selected that have a cross section only 5x15 cm wide. 550 mm.
Also, the rafter log itself is also carried outside the wall of the house. It must be attached to the edge of the ceiling beam itself.
Attaching rafters to beams is one of the important processes during the construction of the roof. In order to prevent possible sliding of the structural elements along the roofing board, the rafter board must be securely fastened using the following mounting options:
Depending on the angle at which the rafters are located, they are joined by either 2 or 1 tooth to the floor beams. This design allows you to distribute pressure from concrete boards to the entire system.
Figure 2. Connection scheme of the rafter with a double tooth, a bolt and a clamp.
Fastening of rafters and girder bars using a single tooth is used if the roof of the building has a steep shape. In other words, if the angle between the board elements and the beam is 35 ° or more. For reliable adhesion of the roof elements, a tooth with a spike is made in the rafter itself.
A special stop is created in the counter part, having a notch for a spike, which is usually recessed 1 / 4-1 / 3 of the total thickness of the counter board. Cut deeper is not worth it, so as not to weaken the beam itself (Fig. 1).
The cutting of sockets to the ceiling beams is usually carried out 250 mm from the extreme side of the hanging element. A single tooth can be made with a spike.
If the roof of the house being built has a rather flat form (less than 35 °), then the rafters are mounted differently. They are reinforced with a help of a cutting with 2 teeth. This is necessary to increase the supporting area of the rafter on each beam. The connection can be made in several ways:
Inserts in the beamed boards are usually created at the same depth. But if you need to install them at different depths, you should take into account an uncomplicated rule. The second tooth is performed at half the thickness of your beam, and the first at 1/3 of the thickness (Fig. 2).
The overlap can be constructed differently. There is an even more complicated mounting option - a joint at the end of a special tightening. Then the tooth-emphasis is placed in the foot of the rafters in such a way that the first plane of the tooth is at the end of the plank beam.
Another plane should rest against the girder created in the bar, which is usually made 1/3 the thickness of your entire beam. Masters advise to build a tooth-emphasis as far as possible from its edge.
By the way, for arranging your entire system, metal or wooden fasteners can be used when installing the beams. Usually use such wooden parts as:
The fixing of rafters is performed using metal elements, from which the following can be distinguished when creating the system:
The roof overlap must be strong enough.
To give the whole structure and your timber greater reliability, rafters and beams are attached with clamps and bolts, and then fastened with wire loops or iron ribbons.
This entire unit is fixed on the wall of a house under construction on an extreme bolt or on a specially bricked crutch.
Materials for rafters:
Tools for rafters.
This ensures the strongest fastening of rafters. This will allow your design to stand for more than a dozen years.
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