What is the bend of space


In the case of an undeveloped roof space, the collar beam is only stressed in the direction of the grain (under pressure), but if the space above is used, it is also stressed in terms of bending due to traffic and dead loads.

Collar beam roofs used to be designed with tenons and offset, but this leads to a weakening of the rafters at the most stressed point. Today, an offset is usually formed with cleats and the collar beam is secured to the rafter on the side with board straps. In many cases, the collar beam is also formed by two pliers-like wooden profiles stiffened against each other with fodder blocks, which are connected to the rafters by dowels or nails. The other construction points correspond to those of the rafter roof.

Expertise on the subject

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