Teardrops n Tiny Travel Trailers

I have searched the Foamies forum specifically for the Subject line with no results.

Has anyone used specifically, Great Stuff's "pro construction adhesive" for joining foam panels ?

I have seen one youtube non-foamie builder that swears by it, including it's ability to glue pink and blue foams to other substrates. But he does not do any foam to foam joints that are structurally crucial.

I have reviewed a million contributors samples of other glue tests, but never seen this product tested in the foamies environment. Perhaps it is a newer product that was not available at the time.

Foam really shouldn't be thought of as a critical structural element, except for the shear bond between panel skins. In this case the area is relatively large, so the glue joint strength can be relatively weak per square inch because there are enough square inches to satisfy the loading requirements. Butt joints between foam pieces will only ever be as strong as the foam itself. The strength of a foam panel, or SIP, comes from the skins and how far apart the inner skin is from the outer skin. The foam only has to separate the skins and keep them from buckling (and the internal cabinets and bulkheads mostly take the buckling loads, so again, we can get away with using foam as our core).

Try to break a butt joint of foam over your knee and it breaks immediately next to the glue joint. Try to peel glued canvas up off of the surface of a foam panel and it peels right up like it's barely attached, breaking the surface granules of foam just under the glue joint. This peeling load is a point load, or line of contact without much area, so it doesn't take much force. But try to shove or pull a glued canvas sideways off of a panel of foam (ala pulling the tablecloth out from under the place settings) and you will understand the useful shear strength that I speak of much better.