What is the name of the beam used to support floors or roofs?

The beam used to support floors or roofs is called a joist. Joists are horizontal structural components that span an open space and are used to support the weight of flooring or roofing materials. They are essential for creating a sturdy framework that can distribute loads evenly across the structure, ensuring stability and safety.

Joists are typically made from materials such as wood, steel, or engineered wood products, which provide the necessary strength and support. Their positioning is critical in framing, as they help create a level surface for the placement of flooring or roofing materials and prevent sagging or deflection over time.

In comparison, rim boards are used at the edges of floor systems, headers are designed to provide support above openings like doors and windows, and stringers are the inclined supports in stair construction. While each of these components plays an important role in carpentry and construction, joists are specifically designated for the purpose of supporting floors and roofs.