S.C. Code Regs. 8-1219. IRC Section R326.3 Story above grade plane

A habitable attic shall be considered a story above grade plane.

Exceptions: A habitable attic shall not be considered to be a story above grade plane provided that the habitable attic meets all the following:

1. The aggregate area of the habitable attic is not greater than three-fourths of the floor area of the story below.

2. The occupiable space is enclosed by the roof assembly above, knee walls, if applicable, on the sides and the floor-ceiling assembly below.

3. The floor of the habitable attic does not extend beyond the exterior walls of the story below.

4. Where a habitable attic is located above a third story, the dwelling unit or townhouse unit shall be equipped with a fire sprinkler system in accordance with Section P2904.