A nosing is the leading edge of a stair tread that extends beyond the riser beneath it. This design feature adds additional surface area for foot placement, which increases safety and stability when using stairs.
Benefits:
- Safety: Nosing increases the surface area of each step, providing more space for foot placement and reducing the likelihood of slipping. This is especially beneficial in environments where steps might be used quickly or in slippery conditions.
- Visibility: By extending slightly over the riser, nosing makes each step more visible, which helps users judge the step depth more accurately and avoid missteps. This is particularly important in dimly lit areas or for users with visual impairments.
- Comfort: The rounded or beveled edge of the nosing can make stairs more comfortable, reducing the impact on the feet when ascending or descending the steps.
| OSHA | IBC | IRC | |
|---|---|---|---|
| Required | Not required | Not required | Not required |
| Size | – | Maximum Nosing = 1.25” | Min ¾ – Max 1.25” |
| Code | 1910.25(f)(5) Stairs must have a minimum tread width of 7 inches (18 cm), measured at the nosing or leading edge or nosing of the tread. Nosing is not required. | 1011.5.2 There is no requirement to provide a nosing, but the maximum nosing projection is 1.25 inches. | R311.7.5 10 inches minium tread depth, plus a required nosing of at least ¾ inch. If a tread of at least 11 inches is provided, there is no required nosing. The maximum permitted nosing is 1.25 inches. |
