This structural joint connects intersecting heavy timbers. One beam receives a central projection, or cog, while the crossing beam receives a matching recess. It is highly effective at resisting lateral movement and is frequently used to secure floor joists to supporting girders without weakening the girder with a full-depth notch.
Heard on the job
The floor system relies on a cog joint at every joist intersection to keep the frame rigid.
Also heard as
- cogged joint
Related terms
Cog
A solid projection left on the end of a timber that fits into a matching notch on another timber.
Mortise-and-tenon joint
A traditional wood joint connecting two pieces at a right angle by inserting a peg into a hole.
Lap joint
A joint formed by overlapping two pieces of wood, often with half the thickness removed from each.