When a loose brick stack reaches a height of 4 feet, it must be tapered back by how many inches for every foot of height above that level?

The correct answer is based on established safety practices in construction, particularly when dealing with retaining wall structures and stacking materials like bricks. When a loose brick stack reaches a height of 4 feet, it is crucial to ensure stability to prevent the risk of collapse. For every foot of height above this 4-foot threshold, tapering back by 2 inches is recommended.

This tapering back reduces the vertical load's direct pressure on the lower layers of bricks, distributing the weight more evenly and enhancing the overall structural integrity. It effectively widens the base of the stack as it rises higher, providing a more secure foundation and reducing the likelihood of topple.

In construction guidelines, this tapering is a standard measure adopted to ensure that stacks of materials maintain stability as they grow taller, especially when working with materials that may not have inherent cohesive strength when stacked loosely.