# Duplex in the 2009 IRC



## benny (Apr 12, 2012)

In looking through the 2009 IRC for duplexes, the only requirements that I find are as follows:

One hour wall separation from foundation to underside of roof (R302.3).

Penetrations through rated walls have size limitations and require a rated fire stop system (R302.4.1).

Membrane penetrations require boxes listed for fire rated assemblies and shall be separated from boxes on the other side of the wall by the listed methods (R302.4.2).

Am I missing anything?


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## benny (Apr 12, 2012)

...besides the usual required for new construction of a single family residence.


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## fatboy (Apr 12, 2012)

And keep this in mind;

2. Wall assemblies need not extend through attic spaces

when the ceiling is protected by not less than 5/8-inch

(15.9 mm) Type X gypsum board and an attic draft

stop constructed as specified in Section R302.12.1 is

provided above and along the wall assembly separating

the dwellings. The structural framing supporting

the ceiling shall also be protected by not less than

1/2-inch (12.7 mm) gypsum board or equivalent.


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