Hello. I am refurbishing my ground floor bathroom which has a solid concrete floor to which I want to add insulation and tile. Please can you tell me the most widely accepted process for this. I have read and considered numerous options - rigid insulation, dpm, chipboard, tile vs insulated cement/tile board vs rigid insulation tile board tile vs insulation, SLC, tile and I am a bit confused about which is best. I want to apply on top of the concrete not dig it up, and I have about 65mm to play with height-wise from the hallway from which there is access before I would need a step up. Thanks in advance.