On Jun 24, 11:36 am, bill wrote:
You have it way backwards.

You need to do some reasearch.

He is. That's why he's asking the question.

1.) Thisnset
2.Backerboard
3.Screws
4.Thinset
5.) Heating Pad(on top of wet thinset, let it dry then lay tile like
normal)
6.)Thinset
7.)Tile

You'll use easy mat or 1/4 inch hardbacker not 1/2 inch

Unless there is a clearance problem there's no prohibition against
using 1/2" backer on the floor.

www.Totalflooring.org

Post question onwww.totalflooring.organd get professional answers if
you like.

Doesn't seem to be too professional of an answer when you ignore what
the OP wrote. He is installing PEX, not electric radiant, so I'm not
sure why you're trying to redesign his system for him.

A goodly number of electric mat radiant manufacturer's prefer the mat
to be attached to the backerboard prior to the thinset being applied.
Wedi board is far superior to using backer board as it insulates the
subfloor and more heating dollars end up in the conditioned space
instead of in the structure - one manufacturer specifically recommends
Wedi under their mat.

R