![Frightened :frightened:](./images/smilies/frightened.gif)
Initially, I had put rubber-bottom rugs over the floor. I glued them down with spray adhesive, but they let go within a year and it was wet under them. The rugs provided almost no insulation value.
![Mad :x](./images/smilies/econ_steamingmad.gif)
Left over from building my boat, I had 2 quarts of 2-part expanding polyurethane foam. I taped the holes underneath, mixed and poured on the liquid to a 1/4 depth across the metal floor. 20 minutes later (on a hot day) it expanded to an almost universal thickness of 1.5 to 2 inches. I used a Surform plane after it hardened to smooth/flatten it out, then put 3/8 inch MDO plywood over it and .024 diamond plate aluminum. I pulled the tape. Water and rust were never a problem again.
![Cool 8)](./images/smilies/econ_kewl.gif)
Polyurethane glue (Gorilla Glue) exposed to air with nothing to keep it from swelling up is single-part expanding polyurethane foam.
![Surprised :o](./images/smilies/econ_oh.gif)
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