Skeptical about foam
I have heard of others using the insulation foam to fix similar problems and understand that they have met with success. It is certainly a much quicker and cheaper solution than the 'proper' way to do it. I would be interested to know how this repair has held up with time.Simply filling the void between core and deck with foam wouldn't take care of the moisture in the core, which is more than likely the cause of the delamination in the first place. Rot requires air and water intrusion into the core material. This is to say that you might have 'fixed' the problem of a spongy deck, but your core might rot out underneath it!Don casey recommends drilling many small holes and attempting to dry the core out with heat fun, acetone, or dry air. If this works then you simply expoxy the laminate back to the newly dry core, fair the holes and your done. However, many times the core is so waterlogged this doesn't work and you must cut the top 'skin' of fiberglass off and replace the core material. It's up to you, but my personal opinion is that the foam fix is sort of a band-aid approach which doesn't actually address the problem. Again, I haven't done that type of repair (the foam one) and I offer my opinions with full respect to others who have given theirs.Cheers,Josh