What is the minimum depth required for stair treads?

The minimum depth required for stair treads is critical for ensuring safety and accessibility. A tread depth of 11 inches allows for a safe and comfortable footing as individuals ascend or descend the stairs. This measurement helps to prevent slips and falls, as a larger surface area provides greater stability.

In building codes and regulations, a tread depth of at least 11 inches is commonly required to promote ease of use, especially in commercial and public buildings where foot traffic can be heavy. The uniformity in depth also contributes to a predictable experience for users, making stairs more approachable for people of all ages and abilities.

Smaller depths, such as 9 or 10 inches, may not provide sufficient space for individuals to place their entire foot securely, potentially leading to a higher incidence of accidents. While 12 inches might provide ample tread space, it may be excessive in many contexts, but it does not violate safety requirements. Therefore, 11 inches stands as the best standard, striking a balance between safety and design.