We are at first fix stage now and I am sold on manifold idea with Hep2o pipes. 

I wanted to check best practice for Hep2o pipe routing on Ground floor. We have very thin joists and we are planning to fill 70mm PIR in them. 

Do people keep pipes in first floor joists and chase down the wall or put the pipes above insulation on suspended floor. 

Also do I need anything to protect Hep2o from PIR or vice versa

 

I searched the Internet and can't find anything relevant. 

Additional question, should I not use Hep2o under cold suspended floor and use copper for ground floor 

What ever you use will need insulation so not sure it matters that much what you use.  If you are insulating makes sense to have the pipes above or in the insulation.