What is the minimum thickness (nominal) for an 8-foot high hollow masonry foundation wall that is 4 feet below finish grade on the exterior?

The minimum thickness for an 8-foot high hollow masonry foundation wall, particularly one that is 4 feet below finish grade, needs to consider several factors such as structural integrity, soil pressure, and lateral loading. A nominal thickness of 8 inches is generally considered adequate for this height and depth, as it provides sufficient strength and stability.

Hollow masonry blocks, when constructed with this thickness, can effectively handle the weight of the wall as well as the lateral forces exerted by the surrounding soil, particularly when buried in the ground. The thickness also allows for the necessary reinforcement typically required for such structural components, ensuring that the wall can withstand the forces exerted on it over time.

Choosing a thickness larger than 8 inches may provide additional safety and resistance to structural failure, but it may not be necessary for a wall of this height and in this application. Thus, 8 inches meets the minimum standards established in most building codes for foundation walls under these conditions.