What are joists typically used for in construction?

Joists are crucial structural components in construction, primarily designed to support floors or ceilings. They are horizontal members that span open spaces and bear loads from above, distributing weight to walls or beams. This structural role is fundamental for ensuring stability and safety within a building. By providing a framework for flooring and ceilings, joists contribute significantly to the overall integrity of a structure, allowing for even weight distribution and providing the necessary strength to prevent sagging or failure over time.

The other options do not accurately represent the primary function of joists in construction. While joists play a vital role in supporting structural elements, they do not serve decorative purposes, directly support the roof structure (which typically involves rafters), or act as insulation within walls. Understanding the specific function of joists is essential for recognizing how they contribute to the overall design and stability of buildings.