What are joists primarily used for in construction?

Joists are primarily horizontal structural members used in construction to frame floor or ceiling structures. They span the distance between walls or beams and provide the necessary support for the weight of the materials above, such as floors or ceilings. This load-bearing capability is crucial for ensuring structural stability and integrity in a building.

In the context of flooring, joists are often part of a framework that distributes weight across a surface. They help resist bending and deformation when subjected to loads, providing a solid foundation for floor finishes and ensuring that the space above is safe and functional.

The other options, though relevant to construction in various ways, do not accurately describe the primary function of joists. Decorative ceilings involve aesthetic elements rather than structural support, and while joists may accommodate electrical wiring or drainage systems, their core purpose remains focused on framing and supporting the overall structure.