I am one of the owners of a family dock. The dock itself is made of up metal pipe with the older strofoam underneath keeping it afloat. The problem is, apparently we have a family of beavers that is chewing the styrofoam and living under the dock. It is steadily sinking a little at a time. The corp here says encapsulated styro is the only acceptable form of floatation. Where would I find this? And how many manufacturers of this product are out there??