Spray foam on party wall

[Gibsonguy]

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

[Marc]

Trying to figure out why anyone would spray foam the attic portion of a party wall in a condo bldg.  Nope, I can't figure it out.

I don't think spray foam passes for intumescent caulk.

Marc

[Chad Fabry]

It doesn't look like spray foam, it looks more like the cementitious stuff they use on structural steel. That said, the party wall isn't necessarily required to be fire rated, it may be a smoke wall if the building has sprinklers and the attics have small enough areas.

 

[Gibsonguy]

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:

http://www.netzerotools.com/handi-foam-m10000-ignition-barrier-5-gallon

 

Edited April 28, 2017 by Gibsonguy

[Gibsonguy]

Maybe it's this? A kind of foam with an intumescent property.

http://www.firechemicals.com/Firex.html 

I can feel the foam like density and insulation properties when I touched it in the attic. This product looks pretty interesting. I can see how thermal resistance is important. I may have answered my own question here. 

 

[Marc]

Party wall between two units in a condo bldg needs a 2-hour rating or maybe that's just in my state.

Marc

Edited April 28, 2017 by Marc

[Gibsonguy]

Thanks Marc. It isn't a condo building... Just a town home. I appreciate the feedback. 

[Marc]

Alright.  Perhaps someone could correct me on terminology: I thought a townhome was one unit in a multi-story condo building.

Marc

[Gibsonguy]

I always thought of it as row housing attached on both sides. Is this one of those Canadian/American things?...

 

[Tom Corrigan]

Condo is a type of ownership. Townhouse is a type of construction. 

Ever see a detached one family building in condo project? It usually confuses everyone.

Tom Corrigan

[John Kogel]

I would just describe it as well as possible in the report.

I think it is an improvement over the usual taped drywall, often with the tape falling off.

A townhouse, in Canada at least, has usually a ground floor entry, a bit of a yard and a second storey.

[Chad Fabry]

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).

[mjr6550]

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.