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Spray foam on party wall


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Hello All,

I just wanted to ask for some feedback. I did an inspection on a 2011 townhome and in the attic, there was spray foam over the party walls. There is a hole at the top of one party wall which I am asking to be sealed, but what are your views on the spray foam? How can it affect the fire rating of the wall? I did not make any holes to measure the drywall and verify a proper 5/8" . How would you write it up?

Thanks in advance for any opinions you may have





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It is definitely spray foam. It may have an intumescent latex barrier on it, but I'm not 100% sure if even that is considered ok. The building doesn't have sprinklers and it's a residential home. I think it would require a fire wall. This is just a new one on me. Wondering if anyone else has seen it or has an opinion on it?

This is an intumescent latex barrier:



Edited by Gibsonguy
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Townhouse= "A single-family dwelling unit constructed in a group of three or more attached units in which each unit extends from the foundation to roof with open space on at least two sides."

Townhouses require a 2-hour separation. The photo does not depict a 2-hour assembly.

Ironically, the same building, but used as apartments can get away with draftstopping (shown in the photo).

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Townhouses are typically considered a separate building and would require a fire separation all (I believe one hour is acceptable under certain conditions, but 2 hours is standard-not positive). A typical gypsum party wall is 2" thick.

In condo building sometimes attic spaces extend over more than one unit. This depend upon the size of the attic. There can be draft-stopping walls between firewalls. In a modern building 5/8" would not be used in a firewall. I believe it would be ok in a draft-stopping wall. Whenever I see something non-standard regarding firewalls I have to look up the details because I don't deal with them often enough. 

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