[Greenbuilding] PEX location in concrete slab

[Chris Green]

Ken Beiser wrote:
 >I was planning to tie the PEX to the rebar putting the PEX closer to 
the slab surface. Does anyone have any preferences or advice?<

These details are fresh in my mind because we just did a slab a few 
weeks ago on the job I'm on now.
The pros tie it to the top of the rebar, as you are planning on doing, 
and of course the rebar itself is spaced about 1"to 1 1/2" from the 
insulation and poly underneath it with those little riser blocks.

If you haven't already purchased the insulation, I would recommend using 
the foil covered material, with the foil side facing up when placing it. 
That foil reflects a lot of heat...
If you also lay down rigid foam on the outside of the foundation, ( 
"exulation" ) the foil faces downwards. I spent five or six  hours  
earlier this week jigsawing together left-over 1" thick pieces to put 
down a 2" layer of foam outside the house and under the slab which will 
hold the front stairs.

As a personal preference, I would also seal the under-slab poly with 
Tuck Tape, but this isn't normally done in my area for some reason....of 
course, it is an awfully dry area and radon gas doesn't seem to be an 
issue locally.

Cheers,

Chris Green.