I'm in a little over my head and the politics are starting to get stirred up. We use 2009 IBC.Proposed A2, came in as a Type VB, but has a mezzanine over 1/3 of the floor area; so two story. The RDP is now calling out a 2 hr wall against the existing building and calling it a IIIB. However the wall has already been framed as a one hour wall and they used standard wood studs (not fire-treated lumber). IBC 602.3 seems to say that Type IIIB is noncombustible with the exception of fire treated wood for studs. I think a VA would be doable. Basically I have a structural engineer playing architect (which our state code allows).Can they use a two-hour wall (standard studs) against the existing building along with one-hour walls on the others and call it a IIIB? I don't see it. I'm thinking either go VA or take the mezzanine down to 1/3 the lower floor area and use a one-hour wall against the existing building and call it a VB. I really appreciate your help!
View attachment 1756
AR-M455N_20130130_145414.pdf
AR-M455N_20130130_145414.pdf
View attachment 1756
AR-M455N_20130130_145414.pdf
AR-M455N_20130130_145414.pdf