The minimum depth of footings below the undisturbed ground surface shall be

The minimum depth of footings below the undisturbed ground surface shall be

• A. 6 Inches
• B. 24 Inches
• C. 18 Inches
• D. 12 Inches

Answer: (A)

The main idea is that footings must be set on stable soil by embedding them a bit below the natural ground surface. The undisturbed ground surface is the natural grade before any excavation. By placing the bottom of the footing at least six inches below that surface, you ensure the footing rests on soil that hasn’t been disturbed by digging and is less prone to surface-related movement. This helps provide reliable bearing capacity and protects against issues like settlement from loose surface soils or frost effects near the surface. Deeper depths (twelve, eighteen, or twenty-four inches) are chosen only in specific circumstances (such as frost depth or poor soils), but for this standard requirement the minimum is six inches.

The main idea is that footings must be set on stable soil by embedding them a bit below the natural ground surface. The undisturbed ground surface is the natural grade before any excavation. By placing the bottom of the footing at least six inches below that surface, you ensure the footing rests on soil that hasn’t been disturbed by digging and is less prone to surface-related movement. This helps provide reliable bearing capacity and protects against issues like settlement from loose surface soils or frost effects near the surface. Deeper depths (twelve, eighteen, or twenty-four inches) are chosen only in specific circumstances (such as frost depth or poor soils), but for this standard requirement the minimum is six inches.