Stair Tread Nosing Requirements

This is another one of those building codes that can be difficult to interpret or understand. This just might be one of the most violated stair building codes that I can think of. Maybe it's just not that big of a deal.

Special Note: Some stairways do not have a stair tread nosing and I couldn't find one building code book that required a stair tread nosing for any type of stairway.

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 This information could be incorrect or outdated.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.

The minimum distance that a stair tread nosing can protrude is 3/4 of an inch The maximum distance is 1 1/4 inches.

Stair tread nosing cannot have more than 1/2" curvature.

The 2010 California Building Code Book does not allow more than a 9/16 of an inch bevel on the stair nosing. Remember, if you're not sure and you're not going to contact your local building department, to verify any of these building codes, stick to the bare minimum or maximum's.

For example, the maximum stair tread nosing requirements for the State of California is 9/16 of an inch and other building codes, it's 1/2". Since one half of an inch is smaller than 9/16 and were talking about maximum curvature or bevel, make sure that your stair nosing doesn't exceed one half of an inch curvature or bevel, just to be safe.



This measurement is from the face of the finished stair riser, to the face of the finished stair tread.		The half inch curvature can be angled or round in shape. It simply can't have a radius larger than one half inch.