Replies

1. 
   Zdesign | Jun 13, 2019 04:27pm | #1

   The drywall layer needs to be continuous and any penetrations need to be 1 hour rated as well. If you get into the 2 hour assemblies its a bit different. Make sure to review the UL Assembly requirements also.

2. Expert Member
   MALCOLM TAYLOR | Jun 13, 2019 09:16pm | #2

   Moose Head,

   I don't know what code you are under, but here the answer is no. The studs at the intersection of the walls, and drywall on the interior walls, provide the equivalent fire rating.

   I'd suggest you talk to your Building inspector to confirm what the requirements are there.

3. Expert Member
   BILL WICHERS | Jun 13, 2019 09:29pm | #3

   All you need to do to build a fire rated wall is to build one of the listed assemblies. For a 1 hour wall, this is usually one layer of 5/8” type X drywall on both sides of a regular 2x4 studwall (either wood or metal studs). 2 hour walls are two layers. All penetrations (wires, pipes, doors, everything) need to be made using listed materials rated for the same number of hours as the wall. It’s important not to miss the firestopping of any holes in the wall assembly.

   You tape and mud the drywall in the usual. The idea is to make sure smoke, hot air, and flame can’t get through the wall anywhere more easily than going through the drywall panels themselves. The purpose of a fire rated wall is to slow down the spread of fire (that’s what the “hour rating” part is about), usually to give people time to get out of a burning structure.

   Bill

4. 
   Peter Yost | Jun 14, 2019 03:08pm | #4

   Good code coverage of this issue in this resource: https://basc.pnnl.gov/code-compliance/air-sealing-and-insulating-common-walls-party-walls-multi-family-buildings-code

   Peter