The dimensional stability of tji joists help them resist warping twisting and shrinking that can lead to squeaky floors.
Tji roof rafters.
The applicability of this detail is based on the joist reaction at the support.
The tji rafter run is 18 feet.
This detail is intended to reinforce the tji j oist end and not to transfer thrust loads at the rafter heel.
In a typical roof framed with dimension lumber the rafters rest on the exterior wall top plate at the lower end and bear against a ridge board at the top.
Conventional framing the first thing to understand is how a roof framed with wood i joists differs structurally from a traditional stick framed roof.
One more important detail.
The second floor flat ceiling will tie into the tji at 12 feet hence the need for a vented assembly.
Technical bulletin tb 805 shows a detail for reinforcement of tji joists slope cut to match a rafter pitch.