Core TradesQuestion 125 of 700
For a one-story wood-frame dwelling on stable soil with no deeper frost-line requirement, what is the MINIMUM depth below the undisturbed ground surface to the bottom of an exterior footing?
a.6 inches
b.9 inches
c.12 inches
d.24 inches
Explanation
The prescriptive minimum is 12 inches below the undisturbed ground surface, which places the bearing surface below loose surface soils. A local frost line may require going deeper, but 12 inches is the baseline. 6 and 9 inches are too shallow to reliably reach firm bearing, and 24 inches exceeds the minimum for this case.
Law Reference: 2025 CA Residential Code §R403.1.4Practice all 700 questions free — no signup required.
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