Under tile insulation and/or Ditra from Schluter

[TimB100]

Hi Chaps

I'm trying to sort out what to put down on my chipboard floor for waterproofing and insulation.

My floor is chipboard and is in a loft conversion. I want underfloor heating and have been advised that I really should have a layer of insulation. I can buy underfloor insulation panels from a number of suppliers, I was going to go for 6mm to prevent too much of a step from an adjacent room. The whole lot inc tiles wants to be around 20mm.

Now I know I need some system to allow for flexing of the chipboard, Ditra from Schluter seems to be popular, but do I need to have insulation under that? Can I use just the undertile insulation boards and lety that handle the flexing?

Thanks

Tim

[gildasd]

Seems a bit low, the norm here is between 6 and 8cm depending on the foam.