International Building Code 419.1
General. Occupancies in Groups I-1, R-1, R-2 and R-3
shall comply with the provisions of this section and other applicable
provisions of this code.
International Building Code 419.2
Separation walls.Walls separating dwelling units in the
same building and walls separating sleeping units in the same
building shall comply with Section 708.
International Building Code 419.3
Horizontal separation. Floor/ceiling assemblies separating
dwelling units in the same buildings and floor/ceiling
assemblies separating sleeping units in the same building shall
be constructed in accordance with Section 711.