What is the term for the parallel beams that provide support for the ceiling or subfloor?

The term for the parallel beams that provide support for the ceiling or subfloor is "joist." Joists are horizontal supports typically made from wood or steel, and they are positioned in parallel rows to form a framework that bears the load of the structure above, such as a floor or ceiling. They help distribute weight evenly across the building, ensuring stability and strength.

Rafters, while also structural elements, are generally used in the construction of roofs rather than floors or ceilings. Studs are vertical framing members used primarily in wall construction. Trusses, on the other hand, are engineered structural components that consist of triangular frameworks. Each of these terms refers to different components in construction, which helps clarify the specific role that joists play in supporting horizontal structures within a building.