The king post truss is one of the most common truss forms used in timber framing. Some, but not all king post trusses utilize struts (diagonal beams coming from the bottom chord). In this detail we take a close look at king post top joinery- and one way to treat the junction of king post, top chord and ridge, which would occur whether or not struts are incorporated.
In order to securely join the top chords (the upper diagonal part of the truss) to the king post (the vertical beam), there is a bit of shaping to all the members. The top chords are cut in a fashion similar to a birds mouth of a rafter sitting on a plate. The diagonal edges of the chords set into matching recesses cut into the king post.
To connect the king post to the horizontal ridge, a full-depth tenon is cut into the post, and it nestles into a matching mortise cut into the ridge beam.
The top chords are further secured to the king post with structural screws, and the king post and ridge are bonded with hardwood pegs to create a strong and attractive king post truss.