At the same time staircase code measurements do allow for some flexibility since most measurements are accompanied by minimums or maximums.
Building basement stairs code.
A prime example is the standard stair width.
Maximum 7 3 4 inch stair riser height.
Minimum 10 inch stair tread depth with nosing or minimum 11 inches with no nosing.
Minimum 6 8 headroom height clearance for stairway.
The nosing on treads believe it or not has a code minimum and maximum of how far the nosing projects over the next stair.
Building codes often require insulation and moisture barriers.
To a maximum of 1 in.
Nosings are required to overhang a minimum of in.
Imagine having a 12 high stair in place with a riser height of 9 and a tread depth of 9.
This becomes an issue when stairs are installed in tight locations under codes that vary greatly from today s current international building code ibc variants.
This stair would have 16 treads 9 deep for a total run of 11 3.
The international residential code for one and two family dwellings irc and the international building code ibc address staircase railings.
As long as the 3 foot width standard is met you can expand the stairs width as far as you wish.
Irc stair railing code.
These are two model codes and are offered as suggested guidelines for local code authorities to follow at their discretion.
Staircase code states that stairs must be 3 feet wide or wider.