In construction terminology, what does 'joist' refer to?

In construction terminology, a 'joist' refers to a horizontal structural element that is used to support beams or the flooring or ceilings above. Joists are typically aligned parallel to one another and spaced at regular intervals to create a framework upon which materials like floorboards or ceiling panels can be attached. This horizontal positioning is crucial for distributing loads, such as the weight of people and furniture in a building, across larger spans and preventing structural sagging or failure.

Understanding the function of joists is important for assessors as well, as they can influence property value and structural integrity. The other options do not accurately describe a joist; vertical support members are known as posts or columns, insulation refers to materials used for thermal resistance, and decorative trim pieces are used for aesthetic purposes and do not bear structural loads.