Extend beams like a carpenter

When extending a beam, a stable connection between the two components must be created. Since beams usually take on a static function, a professional carpenter connection should always be created. Four classic designs are available, which are used by carpenters to "shoe on".

Force effects determine types of connection

Often extending a wooden beam is a repair. After removing damaged, friable and rotted beam parts, fitting a new part to the sawn-off beam is equivalent to making a length connection.

In the case of a professionally executed shoeing, as the longitudinal joining in technical language is called, the static stability is centered on the nature of the dovetailing of the beam. In doing so, several possible forces must be taken into account:

  • bearing load
  • thrust
  • traction
  • sideshifting
  • Twisting and twisting power

Four classic connection methods

In order to use the proper longitudinal connection when restoring a wooden beam, the properties of the four common methods must be observed.

1. Leaf stroke

The simplest type of longitudinal connection for extending the wooden beam is the blade thrust. At each end of the beam to be joined together, half of the beam volume is removed. The two ends are pushed together and glued and / or screwed. Sub-species such as the Gerberstoß can have beveled recesses, which produce greater stability by their vertical course. The blade thrust absorbs the bearing load and compression forces well, but has weaknesses in all other force effects.

2. Straight hook blade

When fastening with a straight hook blade, the respective beam ends are tapered to two different depths. The doubly offset and at the outer edges of the beam lower rejuvenation forms a mutually inserting "hook". Advanced species can be associated with double "hooking" by quadruple vertical displacement of the tapers. The hook blade forms a tension- and pressure-resistant extension of wooden beams.

3rd pin thrust

The pin thrust consists of a beam end of a center groove as a pin and a counter-notch on the opposite end of the beam. A straight groove is inserted into the notch. Subspecies can be implemented with vertical tenon and notch shapes. The symmetrical and double vertical dovetail pin is the most elaborate and stable pin thrust. In addition to compressive strength, this compound offers above all resistance against sideways pushing and pulling forces.

4. Tap leaf kick

The journal thrust is a combination of blade and pin thrust. The taper is provided at a bar end with a groove on the header. Opposite a slot insert serves to connect. In particular when shoeing wooden beams that have supporting functions for roofs or ceilings, this most stable type of connection should be implemented professionally. Their stability also includes twisting and twisting forces from all directions.

Extend only with healthy wood

To avoid creating a static vulnerability by extending a beam, only healthy wood should be spared from removal when working. Brittle, splintering or otherwise damaged wood leads to the limited stability of each and also professionally executed extension when connecting the wooden beams.

Tips & Tricks

If you use professional connection techniques, it is possible to do without screws.

Video Board: How To Install Huge Beams with Joinery