What distinguishes the head-of-wall joint?

The head-of-wall joint is characterized by its specific location at the top of a wall. This joint is crucial in providing a flexible connection between a wall and the structure above it, such as a ceiling or floor slab. Its placement at the top allows for the accommodation of building movement, differential settling, and expansion, which is essential for maintaining the integrity of both the fire-resistance rating and the containment of smoke and heat in the event of a fire.

Understanding the role of the head-of-wall joint is significant for firestop applications, as it is where firestop systems must be installed to ensure they are effective in preventing the passage of fire, smoke, and gases between different building compartments. The proper installation at this location helps to uphold the overall fire safety performance of the building.

Other options do not accurately define the head-of-wall joint: while it may relate to vertical space in terms of separation, it is specifically identified by its horizontal top location. The joint can be found in both interior and exterior walls, not limited to any single type of wall.