Reliably connect wooden beams statically


For the stability of timber trades, the connections of the wooden beams provide each other. A typical roof truss consists of drawbars and additional fittings. Decisive are the force impacts, which are caught, redirected and distributed by a professional connection. The weakest connection determines the construction quality.

Force effects and possible consequences

When connecting wooden beams almost all physical laws regarding the action and propagation of mechanical force are considered. Every single connection has to bear a heavy load and has to absorb additional secondary forces. The directions and types of force are manifold:

  • From above acting pressure load
  • Side-acting pressure load
  • Side-acting traction
  • Vertical acting traction
  • Vertically acting pressure force
  • Vertical pulling force
  • Nonspecific twisting power

The connections must prevent several mechanical components and consequences for the entire timber trade:

  • slip
  • create tension
  • Break
  • Tear
  • splinter
  • Deform

Peak loads and connection points

In the static calculation of a roof truss or the carport, the variables are considered in the force effect. Coverage weight, roof type, wind, precipitation and temperatures provide peak loads leading to the required load levels.

The values ​​for the entire trade can be used to determine the loads for each individual connection of the wooden beams. These differing loads additionally vary due to position and bar thickness. Only in rare cases, a roof truss made of wood beams without screws can develop sufficient bearing capacity and load resistance.

Naturally, the tapping of the beams forms the resistance to the main load at this connection point. In most cases, these are the pressure forces from above. Lateral and vertical forces are absorbed by bolting the beams.

More than the sum of its parts

In addition to the internal connection stability, the tread construction also absorbs total force. Vertical supports and cross braces distribute power and reduce the impact energy on the individual connection points.

The connection of wooden beams to a trade can not be done in isolation to the form of the construction. Due to the nature of the structure, individual connections can be relieved or others more stressed.

Tips & Tricks

If, according to your calculations, you are not conclusive about which load will be exposed to each individual connection of your wooden beams, you should absolutely seek the advice of a specialist such as a carpenter, structural engineer or structural engineer.


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