A king post is a vertical structural member in a traditional truss design, running from the center of the bottom chord up to the peak where the two sloped top chords meet, providing central structural support within the truss’s overall triangulated framework.
This traditional truss configuration, called a king post truss, is one of the oldest and simplest truss designs, historically used in barns, churches, and other structures requiring open interior spans without intermediate columns.
Because king post trusses are often visually striking when left exposed, this traditional design element has found renewed popularity in contemporary architecture seeking a timber-frame aesthetic.
What Does a King Post Involve?
- A vertical member at the truss’s center
- Connection to the bottom chord below
- Connection to the peak where sloped chords meet
- Often traditional joinery in timber-frame applications
Why Are King Posts Important?
Within a king post truss, this central vertical member helps resist the bottom chord’s tendency to sag under load, working in tension to support that horizontal member from the peak above, a structurally elegant solution using minimal material for the achieved span. This efficient use of material is part of why the design remained popular for centuries before more modern engineered truss configurations became available.
Modern applications sometimes use a king post design primarily for its architectural appearance, incorporating the traditional form into contemporary timber-frame or exposed-beam construction even when the actual structural engineering relies on additional modern reinforcement not visible in the exposed timber elements. This blend of historical form and modern engineering keeps the design relevant in contemporary building.
King Post vs. Newel Post
A king post is a structural truss component supporting a roof structure. A newel post serves an entirely different function, anchoring a staircase’s handrail at the top or bottom of a flight, sharing only the word post despite their unrelated structural roles.