A double oven range appliance and a gas burner and floor assembly for an oven appliance are provided. The gas burner and floor assembly includes a cooking chamber bottom panel with a projection defining a plurality of openings. A gas burner is positioned above the plurality of openings. A floor panel is positioned below the cooking chamber bottom panel. An insulation panel is mounted to the floor panel such that the insulation panel is disposed below the plurality of openings. The gas burner and floor assembly can assist with limiting heat transfer along a vertical direction while also providing a suitable flow of air at the gas burner.