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Re: Two Family Dwelling Fire Separation
Chip,
As soon as you go from two units to three units, the one- and two-family dwelling parts no longer apply. Townhouses are defined as three or more, thus the townhouse parts apply.
That means the *2 hour* fire rated wall now may either: a) extend to the roof and the roof is protected for 4 feet to each side of that 2 hour fire rated wall, or, b) the 2 hour fire rated wall extends at least 30 inches above the roof.
If the roof is to be protected to 4 feet to each side of the wall, how can you do that with any openings in there? No plumbing vents, no exhaust vents, no dryer vents, no ridge vents.
Staggering roof sheathing ...
I've always seen it specified to be staggered, however ...
From the 2004 FRC. (underlining is mine)
- R803.2.3 Installation.
- - Wood structural panel used as roof sheathing shall be installed with joints staggered or nonstaggered in accordance with Table R602.3(1), or APA E30 for wood roof framing or with Table R804.3 for steel roof framing.
Thus, it depends on the engineering, I've just never seen any which allowed for "nonstaggered".
I know the trusses are 24" o.c., however, it is common for the first trusses next to the separation wall to be less, which means it takes two spans plus (meaning 3 spans) to make 4 feet.
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