Hello I want to insulate my external garage to use as a games room it's roughly 4.5m squared I have a concrete slab which was laid on a dpm. The walls and ceiling are to be insulated for the floor I wanted to put down a water proof membrane on the slab followed by 100mm jab lite insulation followed by 18mm 8x2 floorboards ideally a floating floor do I need a membrane between the insulation and chip board or is this OK ?
