What structural component bears the weight of a building?

Joists are critical structural components that bear the weight of a building, particularly in the flooring system. They are horizontal beams that span between walls or supports and are designed to support loads from the floor above, distributing these loads down to the building's foundation. The way joists are engineered allows them to effectively handle both live loads (the weight of furnishings, people, and moving objects) and dead loads (the weight of the building materials themselves).

While walls, slabs, and trusses also play important roles in a building's structural integrity, joists specifically focus on supporting flooring systems and transferring loads from one area to another. Walls provide vertical support and enclose spaces; slabs represent a flat surface that creates floors and ceilings; and trusses are used to support roofs, providing an efficient way to span large areas. Each component has its own function within the overall framework of a building, but in terms of direct load-bearing related to floors, joists are the most relevant choice.