Final answer:
Floor joists are designed to support the weight of a structure, specifically between the headers, subfloor, girders, and the second floor. Headers and girders play crucial roles in transferring loads to the joists.
Step-by-step explanation:
Floor joists are a critical part of a structure's support system, typically located between the headers and the subfloor and the girders and the second floor. They essentially serve as the backbone of the floor's support, bearing the weight of everything above them, including the subfloor, finished flooring, and any furniture or people occupying the space. The headers or rim joists, are the parts of the support system that transfer floor and live loads onto the support joists. The girders or beams, on the other hand, support the joists themselves.
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