Fire rated caulking around outlets

JoeNorm

Senior Member
Location
WA
I'd like to seal the small gap between the drywall and my electrical boxes. Is there an appropriate fire rated caulk for this purpose?

thanks
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
If you need to preserve the fire rating of the membrane you probably need to use a putty pad. If you are sealing for draft stopping and just want to up your game you can use the standard fire caulk. However, since merely running a bead of caulk around the edge of a box isn't part of any listed system, you won't really be able to claim any fire resistance, other that the fact it wont torch up like the usual Great Stuff, although Great Stuff does make a "fire barrier" product.
 

tom baker

First Chief Moderator
Staff member
I use the $2.00 latex painters caulk, for non fire wall applications. This is good up to 3/16". Over that I would use water putty which sets up like cement.
 

flashlight

Senior Member
Location
NY, NY
I used plaster of paris mixed with joint compound, sets up slow enough to work, fireproof, and finishes smoother than other products.
(That's not usually my job, should be with the drywall finisher, but faster if I did it rather than raise an issue with GC.)
If it was more than a few boxes, say 5 to 10, then I would ask the GC to have it done.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Electrician
If for some reason it really does need to be fire caulked you will need to use an approved assembly per the UL Orange books, any thing else is a waste of effort and money and should be rejected by a building / fire inspector.

I would say draft stopping is all that is necessary and most caulks will do the job.

Roger
 

DBoone

Senior Member
Location
Mississippi
Occupation
General Contractor
I agree, it's amazing how much draft will come through a building and out or into the receptacle cutouts.

Caulk around the perimeter of the box to seal between drywall and box....what is a good way to seal the knockouts inside a plastic box to keep air from passing through ?
 
Location
Minnesota
Occupation
ee
Caulk around the perimeter of the box to seal between drywall and box....what is a good way to seal the knockouts inside a plastic box to keep air from passing through ?
If not an airtight rated box (or to close a dialated foam perforation in one), acoustic sealant from the outside of the box. from the inside of the box after the fact or remodeling, a UL rated acoustic putty (QuietPutty, PuttyPads etc.) since the caulk makes a mess of the box. Avoid spray foam in a box or where cotiguous with the box’s openings as ignition temperature of the cheap brands (GreatStuff etc.) is 120 C and not UL listed. A lot of folks just seem to use latex caulk, which while not a listed method, seems just fine.
 

DBoone

Senior Member
Location
Mississippi
Occupation
General Contractor
If not an airtight rated box (or to close a dialated foam perforation in one), acoustic sealant from the outside of the box. from the inside of the box after the fact or remodeling, a UL rated acoustic putty (QuietPutty, PuttyPads etc.) since the caulk makes a mess of the box. Avoid spray foam in a box or where cotiguous with the box’s openings as ignition temperature of the cheap brands (GreatStuff etc.) is 120 C and not UL listed. A lot of folks just seem to use latex caulk, which while not a listed method, seems just fine.
Thanks for the response!
 
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