Residential Building Inspector Practice Exam

What is the minimum thickness allowed for masonry walls that are 9 feet in height in a one-story dwelling?

1. 4 inches

2. 5 inches

3. 6 inches

4. 8 inches

The correct answer is: 6 inches

The minimum thickness of masonry walls in residential construction is influenced by structural requirements, stability, and building codes. For walls that reach a height of 9 feet in a one-story dwelling, the minimum thickness of 6 inches is specified to ensure adequate strength and stability. Masonry materials, such as concrete block or brick, require sufficient thickness to withstand lateral and vertical loads, especially at greater heights. A thickness of 6 inches provides enough mass and resistance against potential failure modes such as buckling or cracking due to stress. Additionally, this thickness supports proper connections to other structural elements and ensures compliance with applicable building codes that address load-bearing requirements. Thinner walls, such as options with 4 or 5 inches, may not provide the necessary support and may raise questions regarding safety and durability. An 8-inch wall, while certainly sturdy, exceeds the minimum requirement for this specific height and type of dwelling. Therefore, 6 inches strikes the right balance between structural integrity and code compliance for a masonry wall in this context.