Hi I have an upstairs bedroom and the floorboards are not in great condition (gaps and not very level). So before we put laminate down I am going to cover the floor with sheets of 12mm ply. Question is, If I screw every 150mm on the ply, do I need to leave an expansion gap around the edges, like I would with the laminate? The laminate will be floating, so no nailing or gluing it. Thanks, Alan.
No gap just nice and tight butting up to each board. 150mm is correct and 100mm around the perimeter of each board, choose a screw that will not go the full depth of the floorboards due to any pipework or electrical wiring that may be underneath.