ok...
i filled the "studs" in my express with expanding foam. i used the big gap stuff as the space is 2-3" wide and forms a channel about 50 something inches tall...i used the smaller gap stuff for the rest of the nooks and crannies inside the van where it was impractical to use xps boards.
it filled the gap wonderfully...i worked slowly and layered it as i went up. it sure expanded more than i thought it would so i have some trimming...
what i did not expect was the strength of the expansion OUTWARD towards the body skin...
i now have vertical lines running up the side of my van visible from the outside...sort of like creases...
i cant believe it did that. these "studs" have so many large holes to allow the stuff to expand out into the interior (and it did) that i never would have thought it would do that. ive used all varieties of the stuff in home remodeling countless times, even around windows and doors. im very comfortable with the stuff
i wouldnt say the body is ruined but im so upset.
weather is too crummy to take pics so ill have to do it later. heads up to those that use it in a similar fashion. im really surprised by this.