Shoring must protrude above the top of the excavation by how many inches?

• A. 3 feet
• B. 24 inches
• C. 18 inches
• D. 1 foot

Answer: (C)

Shoring is used to support trench walls and prevent cave-ins, especially near the edge where soil can shift and workers are standing or moving material. The protection must extend above the top of the excavation by a minimum amount so that the shoring stays engaged and provides a safe barrier above the trench opening. The required minimum extension is eighteen inches. This leaves enough overlap to maintain the protective system’s effectiveness even if the trench face starts to move and gives workers and equipment a safer edge to work near. Distances smaller than eighteen inches don’t meet the protection standard, while larger distances exceed the minimum but aren’t the required amount for this rule.