Final answer:
The building code requires floor joists to have complete bearing on their supporting structures, whether wood or metal, to ensure structural integrity.
Step-by-step explanation:
The correct answer to the question “Code says all floor joists need _____ bearing on wood or metal?” is complete bearing. In the context of building construction, floor joists are horizontal structural members used to support the floor.
They must have complete bearing on the support structure, which can be wood or metal, to ensure proper distribution of load and the structural integrity of the building. An incomplete bearing could lead to structural failures, uneven floors, or safety hazards.