An exterior stairway in an R3 occupancy- how far from property line and how to protect...
Some thoughts/ background information....
1) Check with Planning/Zoning to see if an exterior stairway in an R-3 can be located this close to property line!
2) Exterior stairways are talked about in Section 1024.3 of the 2007 CBC. You would need minimum 10 ft separation from property line. I'm not sure that this section applies to our scenario though.
3) Table 602 has exterior wall fire rating information based on fire separation distance (FSD). Footnote "f" does not require fire rating if the FSD is at least 5 ft.
1) If Planning/Zoning allows the exterior stairway to be 3 ft from property, then the exterior stairway should be one-hour fire-resistance construction, OR Heavy Timber construction (Heavy Timber may be used as equivalent to one-hour fire-resistive rating per footnote "d" in Table 601).
2) If the stairway is located such that the closest it gets to the property line is 5 ft, then I would not require fire-resistance construction for the stairway.
If there is no R-3 exception, in a small sloped lot situation how can you get up to an entry door if the only possible location for stairs is either the side yard (3ft) or the front corner, avoiding the garage door. This seems impossible on a 25 to 35 ft wide lots.
How many concrete steps on grade could you build before it becomes a stair? One or more risers according to definition 1002. How can you have any walkway around a building without it being 100% level or possible small slope if at ONE step it becomes a stair and needs 10ft separation from the property line?
Table R302.1 of the IRC indicates that a fire separation distance of five feet would suffice for an exterior stairway.
Chuck daleo, CBO