One of the biggest design issues we're considering for the townhouse we're thinking about building is the partywalls. We wanted to use SIP, but have to deal with properly fire rating and protecting the SIP wall where it is a party wall. There are existing houses on each side, so this is building a SIP house between two existing houses. Typical methods of wrapping and siding the SIP are not possible.

The solution we dug up is maybe using a 'shaft wall' system. We'd lay in a couple sheets of fire rated board as the exterior layer and then the SIP panel would go in as the interior layer.

Anyone seen this before? What are the moisture issues? Other issues? Better solution?

What rating are you trying to acheive?      do you intend to use the SIPs party wall for bearing ?

I usually advise clients to leave panels out of the project for fire rated walls because of the lack of testing. A rated shaft wall assembly is a good idea but it seems costly to have a panel wall built right next to it. I would suggest building a load bearing fire rated wall conventionally for the party walls.

This duplex was built 3 years ago at NTM homes by all volunteer labor and used out tested panel in the partywall as shown installed in the 2nd, 3rd, & 4th picture

http://southernsips.com/job_diy.html


Our panels are tested for 1 hour separation wall assembly and can be used up to 3 stories

If you don't have access to the outside face of the walls, unit masonry is the most practical and cost effective.

Chris K, can you explain how they would assemble your rated wall assembly given their situation of infilling between two townhouses?

Your wall assembly probably has a 1 hour non load bearing rating. That's not a problem I guess, you just have to support your floors & roof with the front and back walls.

Posted By SimonD on 14 Feb 2011 11:37 PM
If you don't have access to the outside face of the walls, unit masonry is the most practical and cost effective.

Chris K, can you explain how they would assemble your rated wall assembly given their situation of infilling between two townhouses?

Your wall assembly probably has a 1 hour non load bearing rating. That's not a problem I guess, you just have to support your floors & roof with the front and back walls.

Oh my gosh, I avoid block as much as possible, scaffolding three stories, it is not at all cost effective or practical to bring in another trade when the SIP framer can accomplish it,

No infilling needed ........balloon frame wall

Simon ...... Don't assume anything!     Our SIP wall assembly is a 1 hour LOAD BEARING assembly ( 1299 # per LFT)


Notice this picture with partywall supporting 2 roof box beams, one from each unit

this issue is, how do you protect the outside of that SIP panel if you can't reach it (because it is infill). Or do steel SIP panels not need to be wrapped, sided?

keep in mind, i'm asking about building a SIP house pre-existing adjoining houses on each side ('rowhouses', townhouses). The issues are how to make the area separation walls (party walls) fire rated, moisture protected, and assemble it all without 'outside' access to the panels once they go up.

Of all the SIP types metal SIPs would be the ones to use in this application if you could prove that putting two 2 layers of fire code drywall to the interior side of the metal SIP wall would create a 1 hour separation. In my opinion, this would satisfy the 'intent' of the code because the adjacent homes would also have their own fire separations. Maybe you could get 'special approval' from your local jurisdiction on this configuration.

Posted By SimonD on 16 Feb 2011 03:08 AM
Of all the SIP types metal SIPs would be the ones to use in this application if you could prove that putting two 2 layers of fire code drywall to the interior side of the metal SIP wall would create a 1 hour separation. In my opinion, this would satisfy the 'intent' of the code because the adjacent homes would also have their own fire separations. Maybe you could get 'special approval' from your local jurisdiction on this configuration.

It has already been proven, That is how the test was conducted