Floor joists should primarily support the weight of the floor between which two elements?

Floor joists are essential structural components that are primarily designed to support the weight of the floor system. They run horizontally and span the distance between the key structural elements in a building. In this context, the correct choice refers to the relationship between floor joists and the other elements that they connect.

The floor joists are supported at their ends by different structural elements, typically girders or beams on one side and the sill plate or foundation on the other. This configuration allows them to effectively distribute the load from the floor surface above (such as furniture, occupants, and other materials) down to these supporting structures. By spanning the space between the sills at the foundation level and the girders, floor joists can maintain the stability and integrity of the floor system.

Understanding this structural layout is crucial for builders to ensure that the load-bearing capacities are sufficient and that the framing adheres to local building codes and standards. The other choices, while they represent important elements in construction, do not accurately describe the primary load-bearing relationship of floor joists. Knowing the role of sills and girders in supporting the joists clarifies their purpose in the overall structural framework of a building.