LOG CONSTRUCTIONS
Log construction: log over log is the most primitive construction of logs, in which the horizontal elements are just set one on top of another.
This system allows a corner, but this construction is covered only by half: one log shuts the surface, and the space between two logs is open.
This stave architecture or log on log system can only be used for objects for drying: hay sheds, sheds for
nuts or chestnuts.
Log construction with notches has to be used for real walls with a shut surface. Here we can use simple mathematics: each log is sawn to halfway.One half sawn log plus one half sawn log composes an even construction.
The mathematical calculation is thus as follows:
½ + ½ = 1
For a connection between logs composing a wall, alternating sawing is needed. Mathematics again:
¼ + ½ + ¼ = 1
The sum is always the same: one, but in the latter system a constructionally sound and sealed wall is built (Juvanec 2009a).
A problem is the quality of the logs: circular logs are natural trunks that are not even, and they are narrower at the top. If necessary, the connection between the logs can be sealed with other sealing material.
This stave system can be used for simple objects only.
Half joints or a timber construction with half-trimmed logs is the most usable in carpentry.
The thickness of a wall is very important for its insulation, thicker material is a better insulator.
The best joints can be built in trimmed logs, the best insulation with whole logs, with a circular profile outside.
A timber construction with half-trimmed logs meets both needs: thick logs in the wall and partially hewn logs at the edge. This system can be found in remote regions or in countries with less wood.
Timber construction with pins uses a transverse movement, prevented with the 'groove and notch' system, but in and out movement is possible. Pins are needed for such occasions. Pins are made of very hard wood. They are vertically inserted into holes, alternately in each beam. The edge can be even and fixed. The inner pin cannot be seen from the outside. A pin connecting only two elements has a head and a point: the head prevents it from falling out, and the point enables exactness of the whole composition. A wooden pin works only when swollen; it uses the moisture from the air. A parched pin becomes smaller, thinner and falls out of the construction. On the other hand, iron and steel nails work with the help of deformation.
Timber construction with overhung timberwork is the strongest construction in wood, where pins are not needed. The beams are joined alternately: ¼ and ¼, with the solid part of ½.
The overhung part can be at least as long as the profile: this means a square in cross-view. The beam could of course be longer – but without any practical reason.
On the front, the overhangs are visible as the profile of the beam, as the length of the overhang plus the shadow of the first element (Zwerger 2012). In normal view, the intersection of the beams can be seen as a decorative element on the elevation. It is not, it is pure construction.
Dovetail construction (visible, open and hidden) is in a visual sense the most interesting system. The principal characteristic of the dovetail system is the design: the shape of the joint prevents it from pulling out.
The dovetail system provides two possibilities: open or hidden. The open system can be seen and, in some places (in Germany, for instance: Werner 1988), the front pieces are designed in various shapes: animals, people, even as letters of the alphabet (Zwerger 2020). A dovetail can be straight or oblong. The latter is very hard professional work, but spherical surfaces are laid more exactly, which means that they are not only more decorative, but more constructionally sound (Juvanec 2012).
The operation of the hidden system in dovetail is the same, but the details are hidden within (Zwerger 2020). It is not as strong as the open variant, but the outer corner is even, without any visible details. A hidden dovetail is used mostly in furniture; it can't be achieved with primitive tools.