Ship manufacturing systems usually use metal sheet metal or wooden panel boards.
Rock-wool or styrofoam are used as a thermal and sound insulation. Metal sheets fold up into two layers by crossing the joints and tighten with rivets. Two-component elastic adhesives are used between the metal sheets, thus achieving the strength of the floor. Metal sheets 2-5 mm are used. It also neccessary to separate it from other constructive parts min 10 mm.
Wooden floating floors are usually done in one layer, but of course it depends on the type of wooden panels.