Refer to a typical single-family dwelling staircase. What is the minimum tread run for stairs (non-spiral) with an occupant load of less than 10?

Refer to a typical single-family dwelling staircase. What is the minimum tread run for stairs (non-spiral) with an occupant load of less than 10?

• A. 8 inches
• B. 12 inches
• C. 10 inches
• D. 9 inches

Answer: (C)

In stair design, the going, or tread run, is the horizontal depth of each step. A safe, comfortable stair needs enough depth for a foot to land securely and for proper footing as you rise or descend. For a typical single‑family dwelling, standards set a minimum going of 10 inches. This height provides enough space for most adults to place the heel and toe comfortably, reducing the risk of slipping or tripping. If the tread run were only 8 or 9 inches, it would be too shallow for safe footing. A 12-inch going would certainly meet safety needs and is acceptable, but it isn’t the minimum required. Therefore, the minimum tread run is 10 inches.

In stair design, the going, or tread run, is the horizontal depth of each step. A safe, comfortable stair needs enough depth for a foot to land securely and for proper footing as you rise or descend. For a typical single‑family dwelling, standards set a minimum going of 10 inches. This height provides enough space for most adults to place the heel and toe comfortably, reducing the risk of slipping or tripping.

If the tread run were only 8 or 9 inches, it would be too shallow for safe footing. A 12-inch going would certainly meet safety needs and is acceptable, but it isn’t the minimum required. Therefore, the minimum tread run is 10 inches.