Under which condition are stepped footings required according to code?

Under which condition are stepped footings required according to code?

• A. Stepped footings are not permitted
• B. If the ground surface slopes more than one unit vertical to ten units horizontal or where necessary to change the top footing surface elevation
• C. Only where necessary to change the top footing surface elevation
• D. Only when the ground surface slopes more than one unit vertical to ten units horizontal

Answer: (B)

Stepped footings are used to follow changes in ground grade so the wall sits on a level, properly bearing surface. The code requires stepping when the ground surface slopes enough that a single horizontal footing surface wouldn’t provide a level bearing, specifically when the slope is steeper than 1 vertical unit in 10 horizontal units (a 1:10 slope). It’s also required whenever it’s necessary to change the top footing surface elevation to match the grade around the wall. If there’s no significant slope and no need to adjust the top-of-footing elevation, stepping isn’t required. This combination—slope greater than 1:10 or a need to alter the top footing elevation—explains why the correct condition is the one that covers both scenarios.

Stepped footings are used to follow changes in ground grade so the wall sits on a level, properly bearing surface. The code requires stepping when the ground surface slopes enough that a single horizontal footing surface wouldn’t provide a level bearing, specifically when the slope is steeper than 1 vertical unit in 10 horizontal units (a 1:10 slope). It’s also required whenever it’s necessary to change the top footing surface elevation to match the grade around the wall. If there’s no significant slope and no need to adjust the top-of-footing elevation, stepping isn’t required. This combination—slope greater than 1:10 or a need to alter the top footing elevation—explains why the correct condition is the one that covers both scenarios.