Final answer:
When installing floor joists, the crown should face upward towards the ceiling. This method helps prevent sagging floors as the house settles and the joists bear weight over time.
Step-by-step explanation:
When installing floor joists, the crown of each joist should face upward, towards the ceiling. The crown refers to the slight arch that can be seen when looking at the edge of the joist from the side. To clarify, the crown is the slight curvature that is typical in lumber, which can cause the board to bow if not accounted for. This upward installation ensures that any deflection under load will help flatten the joist rather than exaggerate the bowing. Additionally, this technique helps reduce the likelihood of having a sagging floor over time as the structure settles and bears weight.