The code requires additional rebar to be used if the spacing between rebar in the stem wall exceeds what measurement?

• A. 12 inches
• B. 24 inches
• C. 18 inches
• D. 6 inches

Answer: (C)

The spacing of vertical rebar in a stem wall is limited to keep the concrete able to carry bending and tensile forces without cracking too widely. When gaps between the bars get larger than a certain distance, the concrete between them can’t transfer tension effectively, leading to larger, uncontrolled cracks and weaker performance under load. Therefore, if the spacing exceeds 18 inches, you need to add more rebar to bring the spacing back to 18 inches or less. This often means adding another vertical bar or staggering additional bars so the wall remains a well-reinforced element that can properly transfer load and resist movement.