Final answer:
The given statement is false. Joists should be installed with the crown facing up, not down. This ensures they level out over time under the weight of the building materials, and prevents exacerbation of natural sagging which can cause structural issues.
Step-by-step explanation:
The statement 'Joists are installed with the crown down' is false. When installing joists, they should actually be installed with the crown facing up. The crown refers to the natural curvature of the wood, where the center of the joist is slightly higher than the ends. This is done with the expectation that over time, and with the weight of the building materials and eventual live load, the joist will settle into a level position rather than sagging. Installing joists with the crown down would exacerbate the natural sagging process and could lead to structural problems.