Tags: 12", 12in, 305mm, bd-1200, bottom, build, build deck, BuildDeck, concrete, concrete floor, concrete roof, Deck, decking, dwg, elevated slab, Floor, front, green roof, insulated roof, long span, mezzanine level, Roof, room, safe, saferoom, section, Shelter, side, slab, span, stirrup, suspended slab, t beam, t-beam, top, tornado shelter, twelve