From trunk to beam

Although you can build a truss with round trunks, it does not happen often. The main reason is that a trunk consists of heartwood surrounded by sapwood. The sapwood is very sensitive to insect attack and is best removed. To make wood joints it is easier to work with rectangular beams. There are various techniques for turning a round trunk into a rectangular beam.

A somewhat heavier trunk can be divided into thinner sections by splitting it. If the grain of the wood is straight enough, a log can be nicely split into two or four parts using a splitting axe and splitting wedges. This places the center of the wood on the outside of the beam, which is not desirable for all beams.

Most beams in half-timbered structures are squared with broad axes.

Video: From trunk to beam - 1. with Mathijs Huyghebaert

Trunks can also be sawn lengthwise, for example with a pit saw. The trunk is often first squared and then sawn through. A trunk can be sawn in half to get two mirrored up braces, for example. Up braces are braces that are often slightly curved and are set up in pairs.

You can also finish logs with a carpenter's adze, but this was mainly done for curved pieces. Adzes are typically used in shipbuilding, but less so in half-timbered construction.

More information about these tools can be found in the carpenter's tool sheets on ID-DOC.