My first question is, is it needed. We are putting tile on the top floor of our home. As I look into radiant floor heating it almost seems like it would be best to put it on the underside of the subfloor. That would require removing parts of the ceiling from the finished basement. Am I completely misunderstanding the best way to install this heating? I would like to avoid putting it on top of the subfloor and using thinset as I see that being a disaster.