rosegamble
Registered User
Hello! I was hoping to get some help with fire-rated wall requirements between duplex units. The 2018 IRC states that the requirements for duplexes are 1 hour (R302.3), but 2 hours for townhouses (R302.2). In general, the rules for duplexes over townhouses seem more lax, both in terms of rating requirement and vertical continuity (parapets, etc).
I have a simple building I'm designing with a demising wall between two residential units (duplex). Per the IRC, the 1 hour rating is required to be continuous from the foundation to the underside of the roof sheathing.
The rated wall in between is a 2x6 with a layer of Type X on each side (UL listed, from USG). The two-story structure has a flat roof, but a high crawl space below a wood-framed first floor assembly. If indeed the rating has to be continuous all the way up, I'm having trouble figuring out the detail for these conditions: (1) junction of demising wall and framed wood floor, and (2) junction of demising wall and the ceiling (in other words, how is the protection maintained during the floor assembly?). Does anyone know of any approved details that meet the intent of IRC 302.2 (i.e. are continuous)?
Thanks so much.
I have a simple building I'm designing with a demising wall between two residential units (duplex). Per the IRC, the 1 hour rating is required to be continuous from the foundation to the underside of the roof sheathing.
The rated wall in between is a 2x6 with a layer of Type X on each side (UL listed, from USG). The two-story structure has a flat roof, but a high crawl space below a wood-framed first floor assembly. If indeed the rating has to be continuous all the way up, I'm having trouble figuring out the detail for these conditions: (1) junction of demising wall and framed wood floor, and (2) junction of demising wall and the ceiling (in other words, how is the protection maintained during the floor assembly?). Does anyone know of any approved details that meet the intent of IRC 302.2 (i.e. are continuous)?
Thanks so much.