IEBC Converting Basement unhabitable space into R-2

[IsaArch]

Hey! I have a question on what may trigger a change of occupancy and compliance with Chapter 10 of IEBC.

This is an R-2 structure of 3 units. Unit #1 is undergoing Level 2 alterations, and it's currently two floors (first and second). The owner would like to finish the basement to add sf and living area to unit #1.
Aside from number of stories and SF compliance, is this considered a change in occupancy since the basement is currently unhabitable space and will now be new R-2 square footage ?
Trying to avoid the sprinkler requirement.

Thank you!!

 

[steveray]

Good first post and Welcome!.....Is the basement currently fire separated? These get a little tough as they may call it R2 or possibly S1 based on what the basement has been used for. A discussion with the AHJ is a good place to start....Finishing the basement may get you sprinklers anyway..People underground gets risky...

 

[classicT]

Get the original CO and see what the basement was classified as. If the whole thing was R-2, no change of occupancy. If it lists S-1/2, then it is likely to be a change of occupancy.

Take note that it would likely be a Level III Alteration all together though- >50% of building area.

2021 IEBC Section 604 Alteration—Level 3
604.1 Scope​

Level 3 alterations apply where the work area exceeds 50 percent of the building area.