Hi, Just bought a house and want to lay floor tiles. Currently the area has a Kardean floor. The area to tile is partly in a new extension and the floor was screed, but this runs into the old part of the house which is floor boards. I also want to put in underfloor heating. My question is can I lay the insulation boards on top of the Kardean flooring (6 mm boards I think) and then board out the floor boarded area and tile over that? Or should I lift the Kardean tiles before Boarding? Any help greatly appreciated.