Our deck insulation kit is for use when installing a gas fire pit on a wood or composite deck. The insulation provides flame and excess heat protection around input flex line connections. This basalt insulation is for inside the fire pit enclosure or bowl and meant to place over a layer of paver blocks (1" min. thickness) commonly found at your local builder's store. Incoming gas stub must protrude through the deck, paver blocks and insulation for fire pit flex line connection. Kit includes basalt insulation and instructions. Basalt insulation measures 39.3" x 39.3" (1 square meter). Larger fire pits will require more pieces, insulation is easily cut with utility knife.