What is the minimum stair tread depth?

What is the minimum stair tread depth?

• A. 10 in
• B. 12 in
• C. 11 in
• D. 13 in

Answer: (C)

Stair tread depth is about how much horizontal space each step provides for the foot to land and rest securely. A sufficient depth helps prevent slipping and ensures consistent foot placement from step to step. The minimum depth recognized by safety standards is 11 inches. That amount gives enough surface for most of the foot to sit on the tread, promoting stability as you step. Treads deeper than this (like 12 or 13 inches) are fine but not required, while a tread depth as small as 10 inches would be considered too shallow and potentially unsafe.

Stair tread depth is about how much horizontal space each step provides for the foot to land and rest securely. A sufficient depth helps prevent slipping and ensures consistent foot placement from step to step.

The minimum depth recognized by safety standards is 11 inches. That amount gives enough surface for most of the foot to sit on the tread, promoting stability as you step. Treads deeper than this (like 12 or 13 inches) are fine but not required, while a tread depth as small as 10 inches would be considered too shallow and potentially unsafe.