What is the primary function of ceiling joists in a building?

The primary function of ceiling joists is to support the roof and prevent walls from being pushed out. These joists are horizontal members that span the width of a room and are critical in maintaining the structural integrity of a building. By transferring the load of the roof down to the walls, ceiling joists help create a stable framework that resists the lateral forces that can occur due to wind or other environmental factors. This structural support is crucial, as it ensures that the building maintains its shape and integrity over time, preventing issues such as wall bulging or structural failure.

While insulating properties, decorative aspects, or accommodating plumbing and electrical systems are also important considerations in building design, they are secondary to the primary role of ceiling joists in load-bearing and structural support.