Minimum Stairway Width
Okay here's another one
of those tricky stairway building codes that I tried to simplify.
The minimum width for any stairway is 44 inch, for any buildings with
more than 50 occupants. This building code might apply to large public
buildings that would require people to pass each other as they walk up
and down the stairs, without being inconvenienced.
Reference: 2012
International Building Code - 1009.4 page 253
The minimum width for any stairway that has less then 49 occupants is 36
inches. This would include individual dwellings or houses.
I simplified the verbiage used in most building codes, so that almost
anyone could understand it. When you read the building codes in the
I.B.C., they're confusing and hard for me to validate.
There are
other exceptions to and for this building code, but these are the
basics.
I suggest that you check out the
maximum hand rail projection
page, because I also found a building code that requires a minimum distance
of 36 inches in between handrails and this would be a problem for anyone
planning on building a stairway smaller than 45 inches wide.
Yes, to
answer your question, these building codes are confusing and can only be
interpreted by your local Building Department officials.
Decorative trim and skirt boards can't protrude more
than an inch and a half into a stairway.
To measure the minimum clear width of any stairway, measure from
finished wall
to finished wall. In the picture above, this measurement would be from
the right side of the finished drywall or wallboard to the left side.