Great Stuff Foam

I’ve seen great stuff foam sprayed into openings but I’ve never seen it applied in the attic this way. Any ideas as to why this would be sprayed here? The insulation was pulled up when I entered the attic otherwise I would not have seen this. It was sprayed in several areas throughout.


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What’s that black stuff out at the eave?

One possibility, Looks like they added a nailer for the drywall to the side of the truss/joist. Great stuff is an awesome drywall glue, perhaps this was a fast remedy to needing something to nail to. If you have a 12’ 1" room and 12’ drywall, and missed the joist, this is a hokey but effective way to hold it still.
Is there a wall below it? Seen it used to fill air gaps to stop the chimney effect.
If this is a manufactured home, they use it as drywall glue. some homes have NO screws in the drywall at all. Simply foam and go. Its actually very strong.

I can only imagine it was sprayed in to seal air leaks…

It was a manufactured home. Thanks for the information.

This PU foam is not from a can but is a spray application (Froth Pack is Dow’s name for their version ). It was applied from above so should be for airsealing, the most common use for this particular product.

I have seen videos of how they build these ceilings, and heard second hand reports… They start with the drywall upside down, and laying flat the whole length of the ceiling. Then they take the trusses on a jig, and lower them on top. Using industrial foam, they spray either side of the drywall along the stud as shown. give it a minute to solidify, and then they lift it up. No screws whatsoever.

The product is made by DOW Chenical, and yes it is used in some factory built homes. Rock still needs to be screwed. spacing for screws are greater when they use this glue.

Thanks for the information guys.

I’m on my second modular home and both ceiligns were done this way.


This is kinda cool. It supports the Foam securing theory.

This one too in particular :57 seconds in. and 4:51