Floor system is based on a 1025mm on center grid using 50mm 2x2, 2x3, or 2x4 joists as long as the bay size and 1x1 or 1x2 spacers of 1000mm length. A second suspended series of bay-length 1x1 joists may be used perpendicular to the main joists to support a sub-floor cladding with rigid insulation panel. Details for this in the Panel systems section.