WPC Co-Extrusion Decking 140 x 20 mm (3.576 kg/m) is the slim board in our dense co-extrusion range. It comes off the same core recipe as the 140 x 23 mm - a volumetric density of 1.277 g/cm3 against 1.280 - so the density is identical and only the height drops by 3 mm. Those 3 mm buy you three things: lower total weight per square metre (0.54 kg less per meter), which matters on rooftops, balconies and mezzanines with load limits; a deck that sits lower, so steps, edge trims and transitions to doors or interior floors are far easier to detail; and less material per square metre, for a friendlier purchase cost. The weather resistance comes from a shell that is grown onto the core during extrusion - one composite body with no interface to peel - so it will not delaminate or lift. No paint, no wax. The density of a solid co-extrusion board, with less height, less weight and less cost - that is the 140 x 20 mm.