Originally Posted By: Brettski
Thanks esshup; good input.
The issues with mesh being "pulled up" in a slab is one of the oldest in the book. The only time you can feel somewhat assured that it was done correctly is when you pour the slab yourself. Even then, it's not as accurate as rebar on chairs. If you saw my threads on the boat launch and our shed, you'd know that I'm a rebar guy. I oughta be; my first job out of high school was making shop drawings for placing and sizing rebar for architectural drawings. Working in a steel warehouse that fabricates rebar helps, too. ;\)
OK, so it's rebar in the slab. Believe me, 2' o.c. is unheard of. It's 12" O.C E/W.
I agree about the 12" o.c to aid in navigating the pour zone; been there, dun that.
5" slab; no biggie. Fibreglas additive; jury's still out, but I'm not opposed to it.
Yeah, familiar with the staples. I know squat about the thermodynamics, but assumed having the tubing centered in the slab would make more sense. I can see the "radiant" wisdom in sandwiching it between the slab and the foam insulator layer. 5/8" ID, eh?...

Tubes located deeper in the concrete will result in more even surface temperature and are less vulnerable to screws drilled to the floor.
To locate the tubes in the concrete you need a friend in the fire department. They have infrared imaging camera. It works very well. You can also use infrared thermometer, push the trigger and pass it over the floor and watch the display. The tube is just below the maximum temp measured. This works best when the floor is turned on after few days of being off.

We live in a barn (aircraft hanger) converted to a house.
0.7 ac leaky pond.