How high must concrete and masonry foundation walls extend above the finish grade level?

Concrete and masonry foundation walls must extend a minimum height above the finish grade level to prevent moisture intrusion and ensure proper drainage away from the foundation. The North Carolina Residential Code specifies that the correct minimum height is 4 inches for unvented foundations and 6 inches for vented foundations.

This height serves crucial purposes: it helps to keep the foundation above potential water accumulation and provides a barrier against soil moisture, which can lead to deterioration and structural issues over time. Ensuring that foundation walls meet this requirement is essential for maintaining the integrity of the building structure.

Thus, option C is accurate as it aligns with the code's requirements regarding the necessary height for foundation walls above grade.