Minimum clear walking path of 26 inches. 5-foot diameter or larger stair will provide this width each tread will have a minimum of 7 1/2 inch tread depth at 12 inches from the narrow edge. All treads will be identical The tread rise shall not be more than 9 1/2 inches high. Minimum headroom of 6 foot 6 inches shall be provided, measuring plumb from the edge of the platform down to the tread below. Landing width shall not be less than the required width of the stairway. Minimum spiral stair tread width is 26 inches – Salter’s code platforms start at 31 inches wide.
Stair balusters shall be spaced so a 4-inch object cannot pass between. The IRC Code permits a 4 3/8 inch space Balcony/Well Enclosure guardrail balusters shall be spaced so a 4-inch object cannot pass.
Balcony/Well Enclosure guardrail height shall not be less than 36 inches – If your state or municipality requires 42-inch tall guardrails, the sales order must reflect this detail.
Handrail grip size:
Type I-Handrails with a circular cross section shall have an outside diameter of at least 1 1/4 inches and not greater than 2 inches. Our standard circular handrail is 1/2 inch diameter. This will address the UBC minimum cross section of 1/2 inch diameter. If the handrail is not circular, it shall have a perimeter dimension not greater than 6 1/4 inches.
Type II-Handrails, with a perimeter greater than 6 1/4 inches, shall provide a graspable finger recess area on both sides of the profile. For further information on our Type II options, please contact our sales department.
Spiral stairways: Spiral stairways are permitted, provided the minimum clear width at and below the handrail shall be 26 inches (660 mm) with each tread having a 190 mm minimum tread depth at 914 mm) from the narrower edge. All treads shall be identical and the rise shall be no more than 241mm. Minimum headroom of 6 feet 6 inches (1982mm) shall be provided.