Joists are supports for which of the following?

Joists are horizontal structural members used to support floors and ceilings. They are crucial in distributing the load from above to the walls or beams below. Typically made from wood or steel, joists are spaced apart to create a framework that can hold the weight of people, furniture, and other items on a floor or ceiling.

In residential construction, joists provide a foundational structure that allows for the installation of flooring materials and can also serve as the base for ceiling finishes. Their role is essential in maintaining the integrity and stability of these horizontal surfaces, ensuring they can perform their functions effectively.

When considering the other options, walls are generally supported by vertical elements such as studs or columns rather than joists. Roof shingles are installed on a roof deck, which is supported by rafters, not joists. Basements are typically supported by foundation walls and do not directly interact with joists in the same way floors and ceilings do. Therefore, the most accurate description of what joists support in construction is floors and ceilings.