Commercial Building Inspector B2Footings and FoundationsMedium
A commercial building inspector is reviewing the design for a continuous concrete footing supporting a 12-inch thick masonry wall. The footing is required to extend a minimum distance beyond the face of the wall on each side. According to the IBC, what is the minimum projection of the footing beyond the face of the masonry wall?
- A6 inches
- B8 inches
- C4 inches
- D2 inches
Show answer & explanationAnswer & explanation
Correct answer: A. 6 inches
IBC Section 1809.4 states that the footing projection beyond the face of the foundation wall or column shall be not less than 2 inches (51 mm) and not more than the thickness of the footing. For a typical masonry wall, a 6-inch projection is common and generally the minimum required to adequately distribute the load.
Why the other options are wrong
- B. 8 inches would provide good load distribution but is not the minimum required by code for this scenario.
- C. 4 inches is a common projection, but 6 inches is often preferred and required for wider walls or heavier loads.
- D. 2 inches is the absolute minimum projection allowed by IBC, but often insufficient for practical load distribution for a 12-inch wall.
Footing Projection
The horizontal distance a footing extends beyond the face of the wall or column it supports, critical for distributing loads over a wider soil area.
- Prevents concentrated stress on the soil.
- Minimum 2 inches (IBC 1809.4).
- Maximum projection is footing thickness.
Memory trick: Footing Width: Wall Extends, Load Spreads