Winder Tread or Step Minimum
The only way we can validate this particular building code
will be to verify the exact location of the
winder walkline.
The
minimum tread depth for a winder type design stairway is 11
inches and will be measured horizontally along the walkline
between steps, from face of nosing on the upper step to face of
nosing on the step you're measuring.
Reference: 2012
International Building Code - 1009.7.2 page 254
Attention: Don't forget to check with your local building department to verify any building codes on this website. This information could be incorrect or outdated. Building codes are updated regularly and to some building departments have different interpretations for certain building codes.