North Carolina Building Contractor License Practice Exam

Which type of mortar bond is typically considered the weakest?

1. Stack bond

2. Running bond

3. Flemish bond

4. English bond

The correct answer is: Stack bond

Stack bond is typically considered the weakest type of mortar bond because it lacks the interlocking structure that other bonds provide. In a stack bond, the bricks are laid directly on top of one another in a vertical line without any staggered joints, which means there are no overlapping bricks to distribute weight and stress effectively. This leads to a weaker overall structure, making it more susceptible to cracking and failure under load. In contrast, other bonds such as running bond, Flemish bond, and English bond incorporate various patterns of overlapping bricks that enhance their strength and stability. The interlocking nature of these bonds allows for better load distribution and provides additional resistance to lateral forces, contributing to a much more durable and resilient masonry wall.