Hi, I have a couple question regarding the preparation of the sub-floor for underfloor heating, I hope someone can help me. I will be having UFH installed in my kitchen, it is a suspended timber floor, the finished surface is to be tiled. I intend to prepare the floor myself, the plan being to remove the existing floor boards (to reduce the final overall build-up) and screw 18mm ply directly to the joists, with a further 10mm on top, running in the other direction, staggering joints as suggested by the BS. 1) Will this provide a stiff enough base (considering I have removed the original floor boards) for my tiling? Or do I need a thicker ply build-up? 2) What build up is required above the ply, ie screed or insulation mats? I expect the answer my depend on whether I am having electric or hot water - Ideally I would like hot water as I have heard it is a 'more even heat' any advice on this and how it would effect the base required would also be much appreciated. Thanks in advance for your help.