LiteDeck Insulating Concrete Form for floors, safe-rooms and roofs. A better option over Span-crete (precast plank) Similar to BuildDeck and Insul-deck. Lite-Deck insulates, drywall can be attached without furring, electrical and plumbing can be recessed.
We stock LiteDeck WRS in 4'x4'x8" and 2'x4'x8" at $6 sf . BuildDeck is another good product that we stock.