What is the minimum tread depth required for winder treads between the vertical planes of adjacent treads at the intersections with the walkline?

The correct minimum tread depth required for winder treads at the intersections with the walkline is 11 inches. This standard is designed to ensure that there is sufficient space for safe foot placement, particularly when negotiating stairs that feature irregular tread configurations, such as winder treads that are narrower than standard treads.

Winder treads are typically used in staircases that change direction, and they are designed to provide a comfortable transition as one steps from one segment of the staircase to another. A minimum width of 11 inches promotes safety by allowing enough room for a foot to land squarely and securely, reducing the risk of slipping or misstepping.

Standards for tread depths are set to maximize both safety and functionality in design, ensuring that staircases can accommodate the needs of users while adhering to building codes. While other options might suggest larger dimensions, the key requirement is a minimum of 11 inches to provide adequate support for users on winder treads.