Deck-O-Seal® DECK-O-FOAM® 1413030 .5" x 3" x 50' Polyethylene Expansion Joint Filler. Deck-O-Foam expansion joint filler is a flexible, lightweight, non-staining, polyethylene, closed-cell expansion joint filler. It is a chemical-resistant, ultraviolet stable, non-absorbent, low-density, cost-effective, compressible foam that offers an extended service life in both interior and exterior applications