- Landing must be as wide as stair, and not less than 36" length
- Ext doors must have landing on each side. shit.
- Stairs min 36" clear
- Handrails project less than 4.5 inches
- Space between handrails > 31.5" with one rail,
27" with two handrails
- Max riser height 7.75". All risers must be within 3/8".
- Min tread depth 10", 3/8" total tolerance.
- Nosing between 3/4" and 1.25 inch with solid risers
- Handrails on at least one side when 4 or more risers
- Handrail height 34-48" from stair nose
- Handrail perimiter 4-6.25". Max cross section 2.25".
rounded edges, radius min 0.25mm. (e.g. sand edges)
- Guards when 30" or grater above grade
- Guard height min 36"
- Guard cannot pass a sphere if 4" diameter
- 6" sphere can pass under guard at stair corner
188.8.131.52 CHAPTER 3 - BUILDING PLANNING:
A. Section R301 - Design criteria. See this section of the IRC except as provided below:...
F. Section R3184.108.40.206 Risers. The riser height shall be not more than eight inches (203mm). ... Open risers are permitted provided that the openings located more than 30 inches (762 mm), as measured vertically, to the floor or grade below do not permit the passage of a four-inch-diameter (102 mm) sphere. Exceptions: (1) The opening between adjacent treads is not limited on spiral stairways. (2) The riser height of spiral stairways shall be in accordance with Section R3220.127.116.11.
G. Section R318.104.22.168 Treads. The tread depth shall be not less than nine inches (229mm)....
Interesting. Note, the 4" sphere rule seems to be applied to open risers in NMAC.
However, also interesting, rise can be 8", tread 9", not the 7.75 and 10" limits of IRC
So... NM could have issue with my open risers.